| Title of Invention | COMPACT HELICAN COMPRESSOR FOR MOBILE USE IN A VEHICLE |
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| Abstract | Disclosed is a compact helical compressor (1,2) for mobile use in a vehicle. Said helical compressor (1,2) comprises a helical compressor unit (1) that is driven by a motor unit. The rotational speed of the motor unit, which is allocated exclusively to the helical compressor unit (1), is adjustable in accordance with a control unit (8) in such a way that the helical compressor unit (1) generates compressed air at a predefined discharge rate that is independent of the drive unit (6) or the vehicle. |
| Full Text | Compact helical compressor for mobile use in a vehicle The present invention relates to a compact helical compressor for mobile use in a motor vehicle comprising a helical compressor unit which is driven by a motor unit. In vehicle technology, helical compressors are used wherever, despite restricted space being available, compressed air has to be generated in order to supply a compressed air on-board system. The design principle, known per se, of a helical compressor is inherently suitable for a particularly compact design and is described, for example, in the Laid-Open Publication DE 34 22 398. From the general prior art it is known that the helical compressors which are used in vehicles, such as utility vehicles or rail vehicles, are driven by means of the drive assembly of the vehicle, for example a diesel engine. This can either be done by directly coupling a helical compressor unit to this motor unit as described, for example, in US 3,811,805 as advantageous embodiment or alternatively it is, however, also possible to provide a transmission with a fixed transmission ratio between the drive assembly of the vehicle as a motor unit and the helical compressor unit. Such a transmission is usually embodied as a V- belt transmission. A disadvantage of this prior art is that the discharge rate of compressed air which is generated by the helical compressor unit is dependent on the rotational speed of the drive assembly of the vehicle. Therefore, the discharge rate of the helical compressor unit drops when the drive assembly rotates less quickly, that is to say for example if the vehicle is braked. Conversely, the discharge rate of the helical 1A compressor unit rises with a rising rotational speed of the drive assembly, for example if the vehicle is accelerated. As a result of this, it is possible to encounter the problem that at operating points at which there is a high demand for compressed air for the vehicle (for example when braking) only a low output rotational speed of the drive assembly is available for generating a corresponding discharge volume of compressed air, and it is not possible to ensure that compressed air is provided in accordance with demand. 2 In order to solve this problem, attempts have previously been made to equip the compressed air system of a vehicle with sufficiently large storage containers for compressed air, from which the necessary compressed air is made available at demand peaks. However, this solution has the disadvantage that such compressed air containers require a correspondingly large installation volume in the vehicle, which runs counter to the objective of a compressed air system which is as compact overall as possible. The object of the present invention is therefore to provide a compact helical compressor for mobile use in a vehicle whose discharge rate of compressed air is largely independent of the f1uctuating rotationa1 speed of the drive assembly. The object is achieved on the basis of a compact helical compressor according to the preamble of claim 1 in conjunction with its defining features. The subsequent dependent claims represent advantageous developments of the invention. The invention includes the technical teaching that the rotational speed of the motor unit which is assigned solely to the helical compressor unit can be adjusted in accordance with a control unit in such a • way that the helical compressor unit generates a predefined discharge rate of compressed air independently of the drive assembly of the vehicle. — 3 — The advantage of the drive of the helical compressor which, according to the invention, can be controlled in accordance with demand is that even at operating points at which there is a high demand for compressed air but with only a low output rotational speed of the drive assembly of the vehicle being available, a sufficient discharge rate of compressed air can be generated. It is largely possible to dispense with additional large compressed air containers. By using the control unit according to the invention it is possible to adjust the discharge rate, and thus the power consumption of the helical compressor according to the invention precisely to the requirements of a suitable motor unit and to adapt to changing requirements during operation at any time without further retrofitting of mechanical components, as is necessary, for example, when changing over the use of buses in public transport between town center mode and suburban mode. The motor unit which exclusively drives the helical compressor unit can be embodied in the manner of a hydraulic drive or in the manner of an electric motor. The decisive factor in the selection of the motor unit within the scope of the present invention is that it is suitable as an actuator element within the scope of the demand-oriented rotational speed controller put into practice here. The use of the controllable hydraulic drive permits energy-saving deactivation of the helical compressor according to the invention without coupling elements which are subject to wear, merely by changing the pivot angle on the hydraulic pump of the hydraulic drive, initiated by the control unit. The controllable hydraulic drive is preferably composed of a hydraulic motor which is connected directly by - 4 - flanges to the helical compressor unit and which an adjustable hydraulic pump supplies with pressure medium necessary for operation, wherein the adjustable hydraulic pump is actuated by means of the control unit. As an alternative to the noncontrollable hydraulic motor on the helical compressor unit it is possible also to provide a controllable hydraulic motor for this if a continuously present circuit is available. Furthermore, it is also conceivable to replace the hydraulic motor alternatively by an electric motor. An electric motor may, for example, be preferably used as a motor unit if the vehicle is embodied in the manner of a hybrid vehicle. In such a hybrid vehicle, the drive of the vehicle is primarily provided by means of an electric motor for which electric current is generated by means of a generator which is driven by a diesel engine. Excess electric current can be fed into a battery here. In such a hybrid vehicle electric current is therefore present in any case in order also to supply the separate electric motor of the helical compressor with the necessary operating energy. The separate electric motor is preferably embodied as a three-phase motor which receives its operating energy via a power inverter from the DC voltage generated by the generator. According to a further measure which improves the invention, the helical compressor unit is composed of preferably three housing parts which are connected to one another without external lines by mounting them one next to the other, and together they form the helical compressor unit. The housing parts are preferably embodied from cast metal. Within the housing parts it is possible to accommodate numerous functions in a space-saving fashion. Furthermore, this design eliminates all the external piping of the compressor functions. - 5 - A first housing part of the multi-component housing advantageously comprises at least one intake nonreturn valve with a compressor helical arrangement connected downstream, with an oil pre-separator unit connected downstream, containing an oil sump with a slosh preventer, with a pressure relief unit connected downstream (when it is switched off) . All these functional parts of the helical compressor unit can be efficiently integrated in a first, common housing part. In a second housing part which is assigned to the first housing part, the outflow contour of the helical compressor unit is preferably formed together with means for returning oil from the oil sump, at; least one oil filter with an optional oil thermostat and at least one oil inflow connector. With the aforementioned two housing parts it is advantageously possible to combine a third housing part. which preferably contains means for accommodating a fine oil filter, means for extracting oil, pressure holding valve means and nonreturn valve means. In the helical compressor unit which is preferably composed of the three abovementioned housing parts with respectively integrated components, it is possible to dispense with all the external and internal piping which is otherwise customary, in particular for relieving pressure when switching off, for returning oil from the fine precipitator etc. According to a further measure which improves the invention there is provision for the hydraulic motor to be coupled by means of a driver disk to the helical compressor unit in which the shaft ends of the hydraulic motor and helical compressor unit engage, wherein the driver disk is damped and lubricated by an oil 'circuit or a continuous grease lubrication means. - 6 - Using a damped driver disk of this type ensures particularly wear-free coupling of the hydraulic motor to the helical compressor unit. For this purpose, elastic couplings or rigid couplings are generally used provided there is no speed-changing drive via V-belts or a transmission. All these coupling means are subject to wear and permit only a rigid connection between the assembly comprising the hydraulic motor and the assembly comprising the helical compressor unit. According to another measure which . improves the invention, the oil circuit, which is necessary to cool the helical compressor unit, can be coupled via a heat; exchanger to a thermostatically controlled cooling circuit of the vehicle. This measure allows a separate temperature control of the oil circuit for cooling the helical compressor unit to be entirely dispensed with. As a cooling circuit of the vehicle it is possible to use the cooling circuit for lubricating the vehicle shaft, differential etc. or the engine cooling circuit. This also makes it possible to connect the heat exchanger directly to the helical compressor unit or alternatively to the drive assembly of the vehicle. Further measures which improve the invention are illustrated in more detail below together with the description of a preferred exemplary embodiment of the invention with reference to the figures, in which: fig. 1 is a block circuit diagram of a helical compressor with peripheral assemblies, fig. 2 is a perspective external view of a compact helical compressor, and fig. 3 is a graphic illustration of an adaptation of the discharge rate of compressed air in accordance with demand by means of appropriate control. - 7 - According to fig. 1, the helical compressor is composed of a helical compressor unit 1 which is driven by a hydraulic motor 2. In this context, the hydraulic motor 2 is coupled to the helical compressor unit 1 by means of a driver disk 3. The two shaft ends of the hydraulic motor 2 or helical compressor unit 1 enqaqe in the driver disk 3. The driver disk 3 is damped and lubricated by an oil circuit (not illustrated here In more detail). The hydraulic motor 2 is connected directly by flanges to the helical compressor unit 1. The hydraulic motor 2 is supplied with the pressure medium necessary for operation via an oi 1 ! i no 4 which is divided into a forward line and return Line. An adjustable hydraulic pump 5 which feeds the oil 1ine 4 is used for this purpose. The drive of the hydraulic pump 5 is provided by means of a secondary output of the drive assembly 6 from the vehicle with an intermediately connected transmission 7, which is embodied here in the manner of a gear mechanism. The actuation of the adjustable hydraulic pump 5, i.e. the angular adjustment of the drive part which is used for this purpose, is carried out in accordance with an electronic controller unit 8. This arrangement ensures that the discharge rate of compressed air which is provided by the helical compressor un.i t 1 is independent of the rotational speed of the drive assembly 6 of the vehicle. The helical compressor unit 1 is cooled here by .means of the cooling circuit 9 of the vehicle (not illustrated in more detail). For this purpose the oil circuit 10 which is necessary to cool the helical compressor unit 1 is coupled via heat exchanger 11 to the thermostatically controlled cooling circuit 9 of the vehicle. - 8 - Fig. 2 shows the compact helical compressor with a hydraulic motor 2 which is connected by flanges to the helical compressor unit 1. The helical compressor unit; 1 is composed of a multi-component housing, with a first housing part 12 containing an intake nonreturn valve 13, with an internal compressor helical arrangement (not shown here) which is connected downstream, with an internal oil precipitator unit which is connected downstream (and contains an oil sump with a slosh preventer), and with a pressure relief unit which is connected downstream. A second housing part 14 of the helical compressor unit 1 embodies the outflow contour of the helical compressor unit 1 and has means for returning oil from the oil sump of the first housing part 12 and an oil filter head 1b. Adjacent to the oi1 filter head 15, an oi1 in flow connector 16 is arranged on the second housing part. 14. A third housing part 17 is equipped with means for accommodating a fi.ne oil filter 18. Likewise, a pressure holding valve 19 and a nonreturn valve 20 are arranged on the third housing part 17. (All these functional parts are known functional units of helical compressors and therefore do not need to be described individually in terms of their interaction at this point). In the diagram according to fig. 3, the discharge rate in 1/min of the compact helical compressor of the type described above is illustrated plotted against the rotational speed 1/min of the drive assembly of the vehicle. It is apparent that the discharge rate of compressed air can be provided for two main demand ranges A and B, independently of the rotational speed of the drive assembly. This is made possible, as described above in detail, by the control unit which ensures that the controllable hydraulic drive can be adjusted in accordance with demand. - 9 - List of Reference Numerals 1. Helical compressor unit 2. Hydraulic motor 3. Driver disk 4. Oil line 5. Hydraulic pump 6. Drive assembly 7. Transmission 8. Control unit 9. Cooling circuit 10. Oil circuit 11. Heat exchanger 12. First housing part 13. Intake nonreturn valve 14. Second housing part 15. Oil filter head 16. Inflow connector 17. Third housing part; 18 . Fine oi1 fi1ter 19. Pressure holding valve 20. Nonreturn valve PCT/EP2005/013356 3003_K PCT - 10 - New Claims 1. A compact helical compressor (1, 2) for supplying a compressed air on-board system in a vehicle comprising a helical compressor unit (1) which is driven by a motor unit, the motor unit being embodied in the manner of a controllable hydraulic drive (2, 5), characterized in that the hydraulic drive is composed of a hydraulic motor (2) which is connected directly by flanges to the helical compressor unit (1) and which an adjustable hydraulic pump (5) supplies with pressure medium necessary for operation via an oil line (4), wherein the adjustable hydraulic pump (5) is actuated by means of a control unit (8), and the rotational speed of the motor unit which is assigned solely to the helical compressor unit (1) being able to be adjusted in accordance with the control unit (8) in such a way that the helical compressor unit (1) generates a predefined discharge rate of compressed air independently of the drive assembly (6) of the vehicle, the helical compressor unit (1) being composed of a multi-component housing, the first housing part (12) of which contains at least one intake nonreturn valve (13) with a compressor helical arrangement connected downstream, with an oil precipitator unit connected downstream, and the second housing part (14) of which contains the outflow contour of the helical compressor unit (1), and the third housing part (17) of which contains means for accommodating a fine oil filter (18). 2. The compact helical compressor as claimed in claim 1, characterized in that the oil precipitator unit contains an oil sump with a slosh preventer, with a pressure relief unit connected downstream when it is switched off. - 11 - 3. The compact helical compressor as claimed in claim 1, characterized in that the second housing part (14) also contains means for returning oil from the oil sump, at least one oil filter head (15) and at least one oil inflow connector (16). 4. The compact helical compressor as claimed in claim 1, characterized in that the third housing part (17) also contains means for extracting oil, a pressure holding valve (19) and a nonreturn valve (20). 5. The compact helical compressor as claimed in claim 1, characterized in that the three housing parts (12, 14, 17) are connected to one another without external lines by mounting them one next to the other, in order to form the helical compressor unit (1). 6. The compact helical compressor as claimed in claim 1, characterized in that the hydraulic motor (2) is coupled by means of a driver disk (3) directly to the helical compressor unit (1) in which the shaft ends of the hydraulic motor (2) and helical compressor unit (1) engage, wherein the driver disk (3) is damped and lubricated by an oil circuit or a continuous grease lubrication means. Disclosed is a compact helical compressor (1,2) for mobile use in a vehicle. Said helical compressor (1,2) comprises a helical compressor unit (1) that is driven by a motor unit. The rotational speed of the motor unit, which is allocated exclusively to the helical compressor unit (1), is adjustable in accordance with a control unit (8) in such a way that the helical compressor unit (1) generates compressed air at a predefined discharge rate that is independent of the drive unit (6) or the vehicle. |
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| Patent Number | 269897 | ||||||||
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| Indian Patent Application Number | 2222/KOLNP/2007 | ||||||||
| PG Journal Number | 47/2015 | ||||||||
| Publication Date | 20-Nov-2015 | ||||||||
| Grant Date | 17-Nov-2015 | ||||||||
| Date of Filing | 18-Jun-2007 | ||||||||
| Name of Patentee | KNORR-BREMSE SYSTEME FUR SCHIENEN-FAHRZEUGE GMBH | ||||||||
| Applicant Address | MOOSACHER STR. 80, 80809 MUNCHEN | ||||||||
Inventors:
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| PCT International Classification Number | F04C 29/00 | ||||||||
| PCT International Application Number | PCT/EP2005/013356 | ||||||||
| PCT International Filing date | 2005-12-13 | ||||||||
PCT Conventions:
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