Title of Invention	HIGH PRESSURE PUMP
Abstract	High-pressure pump (10) having a carrier element (12), a drive shaft (15) mounted rotatably in the carrier element (12), at least one pump unit (13, 13a), which is drivable by the drive shaft (15) and comprises a cylinder housing (14) having a cylinder space (32), which during the intended use is loaded with high pressure and in which is disposed an axially movable high-pressure piston (30) that is in working connection with the drive shaft (15) . The cylinder housing (14) is coupled to the carrier element (12) and the carrier element (12) is formed from a plastics material.

Title of Invention

HIGH PRESSURE PUMP

Abstract

High-pressure pump (10) having a carrier element (12), a drive shaft (15) mounted rotatably in the carrier element (12), at least one pump unit (13, 13a), which is drivable by the drive shaft (15) and comprises a cylinder housing (14) having a cylinder space (32), which during the intended use is loaded with high pressure and in which is disposed an axially movable high-pressure piston (30) that is in working connection with the drive shaft (15) . The cylinder housing (14) is coupled to the carrier element (12) and the carrier element (12) is formed from a plastics material.

Full Text	Description High-pressure pump The invention relates to a high-pressure pump. Such a high-pressure pump is preferably used as a feed pump for delivering fluid for an accumulator injection system for internal combustion engines of motor vehicles. Accumulator injection systems for i.e. engines of motor vehicles, for example in common rail systems, are intended to enable the provision of the required volume rate of flow and the necessary fluid pressure. The high-pressure pump in accumulator injection systems for motor vehicles is subject to extreme loads, in particular to mechanical stresses. In particular, such high-pressure pumps have to be able to take up high forces. As a result, heavy demands are placed both on the material and on the design of the high-pressure pump. As high-pressure pumps are subject' to pressures of for example up to 2000 bar, they have to withstand high stresses. US 5,985,207 discloses an arrangement including an electric motor, which is arranged in a motor housing, and a radial piston pump driven by the electric motor, having a pump housing for accommodating electrohydraulic valves. The pump housing has a pump bearing, the motor housing has a motor bearing. The bearing forces are fed into the pump housing. The object of the invention is to provide a high-pressure pump that even at high pump pressures enables reliable and precise operation while being subject to minimum wear. At the same time, the high-pressure pump is to be economical to manufacture. The object is achieved by the features of the independent claims. Advantageous developments of the invention are indicated in the sub-claims. The invention is distinguished by a high-pressure pump having a carrier element, a drive shaft mounted rotatably in the carrier element, and at least one pump unit, which is drivable by the drive shaft and comprises a cylinder housing having a cylinder space, which during the intended use is loaded with high pressure and in which is disposed an axially movable high-pressure piston that is in working connection with the drive shaft. The cylinder housing is coupled to the carrier element, the carrier element is 'embodied so as to take up forces between the high-pressure piston and the drive shaft, and the carrier element is formed from a plastics material. In the pump unit drivable by the drive shaft, during normal operation of the high-pressure pump a very high pressure is generated in the cylinder space by means of the high-pressure piston. This pressure has the effect that very strong forces may arise between the high-pressure piston and the drive shaft in working connection therewith. In order to be able to take up these forces, the carrier element is conventionally made of a metal. The invention comprises the discovery that plastics materials are also conceivable as a material for the carrier element, preferably if they have a high tensile and compressive strength. It is advantageous that, in the event of the use of a plastics material for the carrier element, a low weight of the high- pressure pump becomes possible. It is moreover possible to manufacture the high-pressure pump at low cost. In an advantageous development of the invention, the carrier element takes the form of a plastic injection-molded part. It is therefore possible also to manufacture complicated geometries of the carrier element. In particular, these complicated geometries may be due to recesses of the add-on parts. With injection molding, moreover, a highly accurate reproduction of detail is possible so that even close tolerances are reproducible. Furthermore, by virtue of the carrier element taking the form of a plastic injection-moulded part, inexpensive designs of the carrier element are possible. In a further particularly preferred embodiment of the invention, the plastics material is selected from the group of thermoset materials. With such plastics materials a high stability under load, in particular a good tensile and compressive strength is achievable. In a further preferred embodiment, the plastics material is selected from the group of mdlding materials made from phenolic compounds. In a particularly preferred manner the plastics material is selected from the Vyncolit group. Vyncolit materials have the advantage that they may exhibit a high tensile and compressive strength and good dimensional stability under temperature variations. For Vyncolit materials, moreover, a high resistance to fuels is achievable. In a further particularly preferred embodiment of the invention, the plastics material is reinforced with fibers from the group of glass fibers and carbon fibers. This enables in particular a high v compressive strength and, accordingly, good mechanical stability of the carrier element. In a further particularly preferred embodiment of the invention, the fibers in the plastics material are at least in sections aligned in one direction. This enables a very high compressive strength and hence very good mechanical stability of the carrier element. In a further particularly preferred embodiment of the invention, the carrier element contains graphite. This has the advantage of enabling particularly good sliding properties of the carrier element. In particular, this makes it possible to achieve a low-friction mounting of the drive shaft in the carrier element. In a further preferred embodiment of the invention, the carrier element has a carrier-element recess and at least one of the pump units is coupled to the carrier element by means of a screw that is introduced into the carrier-element recess. This enables a particularly simple and secure coupling between pump unit and carrier element. In a further particularly preferred embodiment of the invention, the screw is self-tapping. Thus, even without the formation of a thread in the carrier-element recess a secure coupling between pump unit and carrier element may be achieved. In a further particularly preferred embodiment of the invention, a threaded insert is disposed in the carrier-element recess and at least one of the pump units is coupled to the carrier element by means of a screw that is introduced into the threaded insert. In this way, a precise coupling of the pump unit in the carrier element is possible. In a further particularly preferred embodiment of the invention, the high-pressure pump is a radial piston pump having an even number of in each case two pump units disposed coaxially with one another, and in each case two pump units disposed coaxially with one another are coupled to one another by means of a coupling unit. This is particularly preferred because in this way the tensile forces, which arise as a result of the working connection between the high-pressure piston and the drive shaft in the carrier element and may be transmitted to the carrier element, may be taken up by the coupling unit. In a further particularly preferred embodiment of the invention, the coupling unit comprises one bearing associated with each pump unit as well as a tie-bolt, wherein the bearings and the tie-bolt are coupled to one another. Thus, the introduction of forces arising in the carrier element into the coupling unit may be realized in a simple manner. In a further particularly preferred embodiment of the invention, the tie-bolt takes the form of an anti-fatigue bolt. This is particularly advantageous because it allows temperature-related changes in the length of the coupling unit to be compensated. In a further particularly preferred embodiment of the invention, the pump units are hydraulically coupled to one another by a pipe, wherein the pipe is disposed outside of the carrier element, and one of the pump units has a connection element that is hydraulically coupled to the pipe. This makes it possible in a particularly simple way to prevent a loading of the carrier element with high pressure. Exemplary embodiments of the invention are described in more detail below with reference to the drawings, in which; Figure 1 shows a schematic view of a high-pressure pump in a first embodiment in longitudinal section, Figure 2 shows a schematic view of the high-pressure pump in a cross section along the line II-II of Figure 1, Figure 3 shows a perspective view of the high-pressure pump, and Figures 4a, 4b show detail representations of the high-pressure pump. In all of the figures elements of identical design or function are provided with the same reference characters. The figures show a high-pressure pump 10 having a carrier element 12 and pump units 13, 13a, which are disposed at an angle of 180° relative to one another. The high-pressure pump 10 has in the centre a drive shaft 15, which is in working connection with an eccentric ring 16 and is mounted in the carrier element 12 so as to be rotatable anticlockwise in a direction of rotation D (Figure 2). Instead of the eccentric ring 16, a camshaft may be used as drive shaft 15. In this case, the number of delivery- and compression strokes may be defined' by the number of cams. The number of delivery- and/or compression strokes in this case corresponds to the number of cams. The pump units 13, 13a are of an identical construction. In the following description the pump unit 13 is to be representative of all of the pump units. The pump unit 13 substantially comprises a cylinder housing 14, a cylinder space 32 disposed in the cylinder housing 14, a high-pressure piston 30 and a spring 20. The cylinder housing 14, the cylinder space 32, the high-pressure piston 30 and the spring 20 are disposed coaxially with one another. The cylinder housing 14 is formed from a metal, preferably a steel. The high-pressure piston 30 is mounted in an axially movable manner in the cylinder space 32 of the cylinder housing 14 and is in working connection with the eccentric ring 16. The high-pressure piston 30 is held in constant abutment with the eccentric ring 16 by means of the spring 20, which is supported preferably against the cylinder housing 14 and against the high-pressure piston 30. In this way, it is possible to prevent the high-pressure piston 30 from repeatedly lifting off and making renewed contact with the eccentric ring 16, which might result in damage to both the eccentric ring 16 and the high-pressure piston 30. In order to be able to fill the cylinder space 32 with fluid, the cylinder space 32 has a (non-illustrated) cylinder space supply line. The cylinder space 32 further has a (non-illustrated) cylinder space discharge line, through which fluid may be discharged from the cylinder space 32. The cylinder housing 14 is coupled to the carrier element 12. The carrier element 12 is formed from a plastics material, wherein the carrier element preferably takes the form of a plastic injection-moulded part. The carrier element 12 in the illustrated embodiment is of a two-part construction but may alternatively be of an integral design or comprise more than two parts. According to this embodiment the plastics material, from which the carrier element 12 is formed, is a thermoset material. Thermoset materials are capable of bearing extremely high mechanical loads and in particular exhibit good tensile and compressive strength. It is particularly preferred if the plastics material is a Vyncolit (registered trade mark), which may be obtained from the company Vyncolit. NV. These materials, in addition to good tensile and compressive strength, also exhibit good thermal stability. Particularly preferred are Vyncolit X7320, a glass-fiber- and mineral-filled phenolic molding compound with a low coefficient of thermal expansion, and Vyncolit BXE6952, a glass-fiber-reinforced phenolic molding compound with very high elongation at break. Also particularly preferred are Vyncolit materials of the type Vintec (registered trademark), in particular of the types Vintec CF8030, a carbon-fiber-reinforced phenolic molding compound, and Vintec CF8050, a carbon-fiber-reinforced phenolic molding compound, both of a high tensile and compressive strength. According to a developed embodiment the fibers in the plastics material are at least in sections aligned in one direction. In particular, the fibers in the plastics material should be aligned in such a way that the tensile and compressive forces that arise may be taken up well by the carrier element 12. In this way, a particularly high compressive strength of the carrier element is achieved. If the plastics material, from which the carrier element is formed, contains graphite, this is particularly advantageous because, even in the event of . the high-pressure pump 10 running dry, components made of such a material may still possess emergency running properties. The two pump units 13, 13a of the high-pressure pump 10 that are disposed coaxially with one another are coupled to one another by means of one or more coupling units 40. Each of the coupling units 40 comprises in each case a bearing 42 that is associated with one of the pump units 13, 13a and disposed at an outer side 34 of one of the pump units 13, 13a. In each case two bearings 42 are coupled to one another by means of a tie-bolt 44. By virtue of coupling the pump units 13, 13a by means of the coupling units 40, the forces acting in a radially outward direction during operation of the high-pressure pump are taken up particularly well by the coupling unit. The forces acting upon the carrier element 12 may therefore be reduced. The use of the coupling unit 40 on two pump units 13, 13a disposed coaxially with one another may be applied in any desired manner to high-pressure pumps having an even number of pump units 13, 13a, wherein in each case two pump units 13, 13a are disposed coaxially with, and at an angle of 180° to, one another. The carrier element preferably has (non-illustrated) reinforcing elements, preferably reinforcing ribs and/or bracing elements. These make it possible to achieve a high mechanical stability of the carrier element 12, particularly in terms of its compressive and tensile strength. Disposed between the pump units 13, 13a is a pipe 46, by means of which the pump units 13, 13a are hydraulically coupled to one another. The pipe 46 is disposed outside of the carrier element 12. One of the pump units 13, 13a has a connection element 48 that is hydraulically coupled to the pipe 46. By means of this arrangement the fluid that is loaded with high pressure by means of the high-pressure pump 10 may be discharged. The high compressive forces of the fluid therefore act upon the pipe 46, which is preferably formed from a metal, thereby preventing these forces from being transmitted to the carrier element 12 . An application of force to the carrier element 12 may therefore be kept low. Figures 4a and 4b show detail representations of the high-pressure pump 10. The carrier element 12 has a carrier-element recess 36. This allows the precise mounting in the carrier element 12 of threaded elements, preferably a screw 38, as in the present case for coupling the pump unit 13a to the carrier element 12 (Figure 4a). Alternatively, a threaded insert 39 is disposed in the carrier-element recess 36. In particular, given a carrier element 12 in the form of a plastic injection-moulded part, the threaded insert 39 may be directly encapsulated simultaneously with injection molding. The encapsulation of the threaded insert 39 in the carrier element 12 by injection molding is economical to realize and the threaded insert 39 is capable of bearing high mechanical loads. There now follows a detailed description of the mode of operation of the high-pressure pump 10. By virtue of a rotational movement of the drive shaft 15 in a direction of rotation D, the high-pressure piston 30 is moved by means of the eccentric ring 16 radially towards the drive shaft 15. At the same time the cylinder space 32 is filled with fluid. By virtue of the further rotational movement of the drive shaft 15, the high-pressure piston 30 is moved by means of the eccentric ring 16 axially away from the drive shaft 15 and, in so doing, compresses fluid situated in the cylinder space 32. The compressed fluid may finally, after the compression stroke, be discharged through the pipe 46. If the high-pressure pump 10 is for example a high-pressure fuel pump of an injection system of an i.e. engine, then the highly pressurized fluid may pass to a high-pressure fuel accumulator, the so-called common rail. By virtue of the working connection between the drive shaft 15 and the high-pressure piston 30, strong radial forces act in an outward direction owing to the high pressure in the cylinder space 32 in the carrier element 12 especially in the region of the pump units 13, 13a. These forces are taken up by the coupling unit 40 and by the carrier element 12 made of plastics material. Furthermore, because of the rotational movement of the drive shaft 15 in the carrier element 12 and the resultant friction in the area of contact between the drive shaft 15 and the carrier element 12 strong tangential forces act in this area of contact, which may be taken up by the carrier element 12 made of plastics material. We claim: 1. A high-pressure pump (10), having - a carrier element (12), - a drive shaft (15) mounted rotatably in the carrier element (12) - at least one pump unit (13/ 13a), which is drivable by the drive shaft (15) and comprises a cylinder housing (14) having a cylinder space (32), which during the intended use is loaded with high pressure and in which is disposed an axially movable high-pressure piston (30) that is in working connection with the drive shaft (15), wherein the cylinder housing (14) is coupled to the carrier element (12) and the carrier element (12) is embodied so as to take up forces between the high- pressure piston (30) and the drive shaft (15) and the carrier element (12) is formed from a plastics material. 2. The high-pressure pump (10) as claimed in claim 1, wherein the carrier element (12) takes the form of a plastic injection-moulded part. 3. The high-pressure pump (10) as claimed in claim 1 or 2, wherein the plastics material is selected from the group of thermoset materials. 4. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the plastics material is selected from the group of molding materials made from phenolic compounds. 5. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the plastics material is selected from the Vyncolit group. The high-pressure pump (10) 'as claimed in one of the preceding claims, wherein the plastics material is reinforced with fibers from the group of glass fibers and carbon fibers. The high-pressure pump (10) as claimed in claim 5, wherein the fibers in the plastics material are at least in sections aligned in one direction. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the carrier element (12) contains graphite. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the carrier element (12) has a carrier-element recess (36) and at least one of the pump units (13, 13a) is coupled to the carrier element (12) by means of a screw (38) that is introduced into the carrier-element recess (36). The high-pressure pump (10) as claimed in claim 9, wherein the screw (38) is self-tapping. The high-pressure pump (10) as claimed in one of the preceding claims, wherein in the carrier-element recess (36) a threaded insert (39) is disposed and at least one of the pump units (13, 13a) is coupled to the carrier element (12) by means of the screw (38) that is introduced into the threaded insert (39). The high-pressure pump (10) as claimed in one of the preceding claims, wherein the high-pressure pump (10) is a radial piston pump having an even number of in each case two pump units (13, 13a) disposed coaxially with one another, and in each case two pump units (13, 13a) disposed coaxially with one another are coupled to one another by means of a coupling unit (40). 13. The high-pressure pump (10) as claimed in claim 12, wherein the coupling unit (40) comprises one bearing (42) associated with each pump unit (13, 13a) as well as a tie-bolt (44), and the bearings (42) and the tie-bolt (44) are coupled to one another. 14. The high-pressure pump (10) as claimed in claim 13, wherein the tie-bolt (44) takes the form of an anti-fatigue bolt. 15. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the pump units (13, 13a) are hydraulically coupled to one another by a pipe (46) , wherein the pipe (46) is disposed outside of the carrier element (12), and one of the ' pump units (13, 13a) has a connection element (48) that is hydraulically coupled to the pipe (46). 16. A high-pressure pump substantially as hereinbefore described with reference to the accompanying drawings.

Full Text

Description
High-pressure pump
The invention relates to a high-pressure pump.
Such a high-pressure pump is preferably used as a feed pump for delivering fluid for an accumulator injection system for internal combustion engines of motor vehicles.
Accumulator injection systems for i.e. engines of motor vehicles, for example in common rail systems, are intended to enable the provision of the required volume rate of flow and the necessary fluid pressure. The high-pressure pump in accumulator injection systems for motor vehicles is subject to extreme loads, in particular to mechanical stresses. In particular, such high-pressure pumps have to be able to take up high forces. As a result, heavy demands are placed both on the material and on the design of the high-pressure pump.
As high-pressure pumps are subject' to pressures of for example up to 2000 bar, they have to withstand high stresses.
US 5,985,207 discloses an arrangement including an electric motor, which is arranged in a motor housing, and a radial piston pump driven by the electric motor, having a pump housing for accommodating electrohydraulic valves. The pump housing has a pump bearing, the motor housing has a motor bearing. The bearing forces are fed into the pump housing.
The object of the invention is to provide a high-pressure pump that even at high pump pressures enables reliable and precise operation while being subject to minimum wear. At the same

time, the high-pressure pump is to be economical to manufacture.
The object is achieved by the features of the independent claims. Advantageous developments of the invention are indicated in the sub-claims.
The invention is distinguished by a high-pressure pump having a carrier element, a drive shaft mounted rotatably in the carrier element, and at least one pump unit, which is drivable by the drive shaft and comprises a cylinder housing having a cylinder space, which during the intended use is loaded with high pressure and in which is disposed an axially movable high-pressure piston that is in working connection with the drive shaft. The cylinder housing is coupled to the carrier element, the carrier element is 'embodied so as to take up forces between the high-pressure piston and the drive shaft, and the carrier element is formed from a plastics material.
In the pump unit drivable by the drive shaft, during normal operation of the high-pressure pump a very high pressure is generated in the cylinder space by means of the high-pressure piston. This pressure has the effect that very strong forces may arise between the high-pressure piston and the drive shaft in working connection therewith. In order to be able to take up these forces, the carrier element is conventionally made of a metal. The invention comprises the discovery that plastics materials are also conceivable as a material for the carrier element, preferably if they have a high tensile and compressive strength.
It is advantageous that, in the event of the use of a plastics material for the carrier element, a low weight of the high-

pressure pump becomes possible. It is moreover possible to manufacture the high-pressure pump at low cost.
In an advantageous development of the invention, the carrier element takes the form of a plastic injection-molded part. It is therefore possible also to manufacture complicated geometries of the carrier element. In particular, these complicated geometries may be due to recesses of the add-on parts. With injection molding, moreover, a highly accurate reproduction of detail is possible so that even close tolerances are reproducible. Furthermore, by virtue of the carrier element taking the form of a plastic injection-moulded part, inexpensive designs of the carrier element are possible.
In a further particularly preferred embodiment of the invention, the plastics material is selected from the group of thermoset materials. With such plastics materials a high stability under load, in particular a good tensile and compressive strength is achievable.
In a further preferred embodiment, the plastics material is selected from the group of mdlding materials made from phenolic compounds. In a particularly preferred manner the plastics material is selected from the Vyncolit group. Vyncolit materials have the advantage that they may exhibit a high tensile and compressive strength and good dimensional stability under temperature variations. For Vyncolit materials, moreover, a high resistance to fuels is achievable.
In a further particularly preferred embodiment of the invention, the plastics material is reinforced with fibers from the group of glass fibers and carbon fibers. This enables in particular a high v compressive strength and, accordingly, good mechanical stability of the carrier element.
In a further particularly preferred embodiment of the invention, the fibers in the plastics material are at least in sections aligned in one direction. This enables a very high compressive strength and hence very good mechanical stability of the carrier element.
In a further particularly preferred embodiment of the invention, the carrier element contains graphite. This has the advantage of enabling particularly good sliding properties of the carrier element. In particular, this makes it possible to achieve a low-friction mounting of the drive shaft in the carrier element.
In a further preferred embodiment of the invention, the carrier element has a carrier-element recess and at least one of the pump units is coupled to the carrier element by means of a screw that is introduced into the carrier-element recess. This enables a particularly simple and secure coupling between pump unit and carrier element.
In a further particularly preferred embodiment of the invention, the screw is self-tapping. Thus, even without the formation of a thread in the carrier-element recess a secure coupling between pump unit and carrier element may be achieved.
In a further particularly preferred embodiment of the invention, a threaded insert is disposed in the carrier-element recess and at least one of the pump units is coupled to the carrier element by means of a screw that is introduced into the threaded insert. In this way, a precise coupling of the pump unit in the carrier element is possible.
In a further particularly preferred embodiment of the invention, the high-pressure pump is a radial piston pump having an even number of in each case two pump units disposed coaxially with one another, and in each case two pump units disposed coaxially with one another are coupled to one another by means of a coupling unit. This is particularly preferred because in this way the tensile forces, which arise as a result of the working connection between the high-pressure piston and the drive shaft in the carrier element and may be transmitted to the carrier element, may be taken up by the coupling unit.
In a further particularly preferred embodiment of the invention, the coupling unit comprises one bearing associated with each pump unit as well as a tie-bolt, wherein the bearings and the tie-bolt are coupled to one another. Thus, the introduction of forces arising in the carrier element into the coupling unit may be realized in a simple manner.
In a further particularly preferred embodiment of the invention, the tie-bolt takes the form of an anti-fatigue bolt. This is particularly advantageous because it allows temperature-related changes in the length of the coupling unit to be compensated.
In a further particularly preferred embodiment of the invention, the pump units are hydraulically coupled to one another by a pipe, wherein the pipe is disposed outside of the carrier element, and one of the pump units has a connection element that is hydraulically coupled to the pipe. This makes it possible in a particularly simple way to prevent a loading of the carrier element with high pressure.
Exemplary embodiments of the invention are described in more detail below with reference to the drawings, in which;
Figure 1 shows a schematic view of a high-pressure pump in a first embodiment in longitudinal section,
Figure 2 shows a schematic view of the high-pressure pump in a cross section along the line II-II of Figure 1,
Figure 3 shows a perspective view of the high-pressure pump, and
Figures 4a, 4b show detail representations of the high-pressure pump.
In all of the figures elements of identical design or function are provided with the same reference characters.
The figures show a high-pressure pump 10 having a carrier element 12 and pump units 13, 13a, which are disposed at an angle of 180° relative to one another.
The high-pressure pump 10 has in the centre a drive shaft 15, which is in working connection with an eccentric ring 16 and is mounted in the carrier element 12 so as to be rotatable anticlockwise in a direction of rotation D (Figure 2). Instead of the eccentric ring 16, a camshaft may be used as drive shaft 15. In this case, the number of delivery- and compression strokes may be defined' by the number of cams. The number of delivery- and/or compression strokes in this case corresponds to the number of cams.
The pump units 13, 13a are of an identical construction. In the following description the pump unit 13 is to be representative of all of the pump units.
The pump unit 13 substantially comprises a cylinder housing 14, a cylinder space 32 disposed in the cylinder housing 14, a high-pressure piston 30 and a spring 20. The cylinder housing 14, the cylinder space 32, the high-pressure piston 30 and the spring 20 are disposed coaxially with one another. The cylinder housing 14 is formed from a metal, preferably a steel.
The high-pressure piston 30 is mounted in an axially movable manner in the cylinder space 32 of the cylinder housing 14 and is in working connection with the eccentric ring 16. The high-pressure piston 30 is held in constant abutment with the eccentric ring 16 by means of the spring 20, which is supported preferably against the cylinder housing 14 and against the high-pressure piston 30. In this way, it is possible to prevent the high-pressure piston 30 from repeatedly lifting off and making renewed contact with the eccentric ring 16, which might result in damage to both the eccentric ring 16 and the high-pressure piston 30.
In order to be able to fill the cylinder space 32 with fluid, the cylinder space 32 has a (non-illustrated) cylinder space supply line. The cylinder space 32 further has a (non-illustrated) cylinder space discharge line, through which fluid may be discharged from the cylinder space 32.
The cylinder housing 14 is coupled to the carrier element 12. The carrier element 12 is formed from a plastics material, wherein the carrier element preferably takes the form of a plastic injection-moulded part. The carrier element 12 in the
illustrated embodiment is of a two-part construction but may alternatively be of an integral design or comprise more than two parts.
According to this embodiment the plastics material, from which the carrier element 12 is formed, is a thermoset material. Thermoset materials are capable of bearing extremely high mechanical loads and in particular exhibit good tensile and compressive strength. It is particularly preferred if the plastics material is a Vyncolit (registered trade mark), which may be obtained from the company Vyncolit. NV. These materials, in addition to good tensile and compressive strength, also exhibit good thermal stability. Particularly preferred are Vyncolit X7320, a glass-fiber- and mineral-filled phenolic molding compound with a low coefficient of thermal expansion, and Vyncolit BXE6952, a glass-fiber-reinforced phenolic molding compound with very high elongation at break. Also particularly preferred are Vyncolit materials of the type Vintec (registered trademark), in particular of the types Vintec CF8030, a carbon-fiber-reinforced phenolic molding compound, and Vintec CF8050, a carbon-fiber-reinforced phenolic molding compound, both of a high tensile and compressive strength.
According to a developed embodiment the fibers in the plastics material are at least in sections aligned in one direction. In particular, the fibers in the plastics material should be aligned in such a way that the tensile and compressive forces that arise may be taken up well by the carrier element 12. In this way, a particularly high compressive strength of the carrier element is achieved.
If the plastics material, from which the carrier element is formed, contains graphite, this is particularly advantageous

because, even in the event of . the high-pressure pump 10 running dry, components made of such a material may still possess emergency running properties.
The two pump units 13, 13a of the high-pressure pump 10 that are disposed coaxially with one another are coupled to one another by means of one or more coupling units 40. Each of the coupling units 40 comprises in each case a bearing 42 that is associated with one of the pump units 13, 13a and disposed at an outer side 34 of one of the pump units 13, 13a. In each case two bearings 42 are coupled to one another by means of a tie-bolt 44. By virtue of coupling the pump units 13, 13a by means of the coupling units 40, the forces acting in a radially outward direction during operation of the high-pressure pump are taken up particularly well by the coupling unit. The forces acting upon the carrier element 12 may therefore be reduced. The use of the coupling unit 40 on two pump units 13, 13a disposed coaxially with one another may be applied in any desired manner to high-pressure pumps having an even number of pump units 13, 13a, wherein in each case two pump units 13, 13a are disposed coaxially with, and at an angle of 180° to, one another.
The carrier element preferably has (non-illustrated) reinforcing elements, preferably reinforcing ribs and/or bracing elements. These make it possible to achieve a high mechanical stability of the carrier element 12, particularly in terms of its compressive and tensile strength.
Disposed between the pump units 13, 13a is a pipe 46, by means of which the pump units 13, 13a are hydraulically coupled to one another. The pipe 46 is disposed outside of the carrier element 12. One of the pump units 13, 13a has a connection element 48 that is hydraulically coupled to the pipe 46. By

means of this arrangement the fluid that is loaded with high pressure by means of the high-pressure pump 10 may be discharged. The high compressive forces of the fluid therefore act upon the pipe 46, which is preferably formed from a metal, thereby preventing these forces from being transmitted to the carrier element 12 . An application of force to the carrier element 12 may therefore be kept low.
Figures 4a and 4b show detail representations of the high-pressure pump 10. The carrier element 12 has a carrier-element recess 36. This allows the precise mounting in the carrier element 12 of threaded elements, preferably a screw 38, as in the present case for coupling the pump unit 13a to the carrier element 12 (Figure 4a). Alternatively, a threaded insert 39 is disposed in the carrier-element recess 36. In particular, given a carrier element 12 in the form of a plastic injection-moulded part, the threaded insert 39 may be directly encapsulated simultaneously with injection molding. The encapsulation of the threaded insert 39 in the carrier element 12 by injection molding is economical to realize and the threaded insert 39 is capable of bearing high mechanical loads.
There now follows a detailed description of the mode of operation of the high-pressure pump 10.
By virtue of a rotational movement of the drive shaft 15 in a direction of rotation D, the high-pressure piston 30 is moved by means of the eccentric ring 16 radially towards the drive shaft 15. At the same time the cylinder space 32 is filled with fluid. By virtue of the further rotational movement of the drive shaft 15, the high-pressure piston 30 is moved by means of the eccentric ring 16 axially away from the drive shaft 15 and, in so doing, compresses fluid situated in the
cylinder space 32. The compressed fluid may finally, after the compression stroke, be discharged through the pipe 46. If the high-pressure pump 10 is for example a high-pressure fuel pump of an injection system of an i.e. engine, then the highly pressurized fluid may pass to a high-pressure fuel accumulator, the so-called common rail.
By virtue of the working connection between the drive shaft 15 and the high-pressure piston 30, strong radial forces act in an outward direction owing to the high pressure in the cylinder space 32 in the carrier element 12 especially in the region of the pump units 13, 13a. These forces are taken up by the coupling unit 40 and by the carrier element 12 made of plastics material. Furthermore, because of the rotational movement of the drive shaft 15 in the carrier element 12 and the resultant friction in the area of contact between the drive shaft 15 and the carrier element 12 strong tangential forces act in this area of contact, which may be taken up by the carrier element 12 made of plastics material.

We claim:
1. A high-pressure pump (10), having
- a carrier element (12),
- a drive shaft (15) mounted rotatably in the carrier element (12)
- at least one pump unit (13/ 13a), which is drivable by
the drive shaft (15) and comprises a cylinder housing
(14) having a cylinder space (32), which during the
intended use is loaded with high pressure and in which
is disposed an axially movable high-pressure piston (30)
that is in working connection with the drive shaft (15),
wherein the cylinder housing (14) is coupled to the
carrier element (12) and the carrier element (12) is
embodied so as to take up forces between the high-
pressure piston (30) and the drive shaft (15) and the
carrier element (12) is formed from a plastics material.
2. The high-pressure pump (10) as claimed in claim 1, wherein the carrier element (12) takes the form of a plastic injection-moulded part.
3. The high-pressure pump (10) as claimed in claim 1 or 2, wherein the plastics material is selected from the group of thermoset materials.
4. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the plastics material is selected from the group of molding materials made from phenolic compounds.
5. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the plastics material is selected from the Vyncolit group.

The high-pressure pump (10) 'as claimed in one of the
preceding claims, wherein the plastics material is
reinforced with fibers from the group of glass fibers and
carbon fibers.
The high-pressure pump (10) as claimed in claim 5, wherein the fibers in the plastics material are at least in sections aligned in one direction.
The high-pressure pump (10) as claimed in one of the preceding claims, wherein the carrier element (12) contains graphite.
The high-pressure pump (10) as claimed in one of the preceding claims, wherein the carrier element (12) has a carrier-element recess (36) and at least one of the pump units (13, 13a) is coupled to the carrier element (12) by means of a screw (38) that is introduced into the carrier-element recess (36).
The high-pressure pump (10) as claimed in claim 9, wherein the screw (38) is self-tapping.
The high-pressure pump (10) as claimed in one of the preceding claims, wherein in the carrier-element recess
(36) a threaded insert (39) is disposed and at least one of the pump units (13, 13a) is coupled to the carrier element
(12) by means of the screw (38) that is introduced into the threaded insert (39).
The high-pressure pump (10) as claimed in one of the preceding claims, wherein the high-pressure pump (10) is a radial piston pump having an even number of in each case

two pump units (13, 13a) disposed coaxially with one another, and in each case two pump units (13, 13a) disposed coaxially with one another are coupled to one another by means of a coupling unit (40).
13. The high-pressure pump (10) as claimed in claim 12, wherein the coupling unit (40) comprises one bearing (42) associated with each pump unit (13, 13a) as well as a tie-bolt (44), and the bearings (42) and the tie-bolt (44) are coupled to one another.
14. The high-pressure pump (10) as claimed in claim 13, wherein the tie-bolt (44) takes the form of an anti-fatigue bolt.
15. The high-pressure pump (10) as claimed in one of the preceding claims, wherein the pump units (13, 13a) are hydraulically coupled to one another by a pipe (46) , wherein the pipe (46) is disposed outside of the carrier element (12), and one of the ' pump units (13, 13a) has a connection element (48) that is hydraulically coupled to the pipe (46).
16. A high-pressure pump substantially as hereinbefore described with reference to the accompanying drawings.

Documents:

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Patent Number

270258

Indian Patent Application Number

6817/DELNP/2008

PG Journal Number

50/2015

Publication Date

11-Dec-2015

Grant Date

07-Dec-2015

Date of Filing

07-Aug-2008

Name of Patentee

CONTINENTAL AUTOMOTIVE GMBH

Applicant Address

VAHRENWALDER STRABE 9, 30165 HANNOVER, GERMANY.

Inventors:

#	Inventor's Name	Inventor's Address
1	LEWENTZ, GUNTER	FATIMASTR. 13, 93093 DONAUSTAUF, GERMANY.

PCT International Classification Number

F04B 1/04

PCT International Application Number

PCT/EP2006/069838

PCT International Filing date

2006-12-18

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2006 006 555.7	2006-02-13	Germany