Title of Invention

"A VARIABLE-CAPACITY TURBOCHARGER WHICH CONTROLS THE OPENING DEGREE OF NOZZLE VANES"

Abstract

The object of this invention is to eliminate the quantity of exhaust gas supplied to the turbine without going through the channels between the nozzle vanes provided in a variable-capacity turbocharger. The nozzle unit 100 in the turbocharger 10 has; a mounting plate 102 and a side plate 104 installed in a recession 20 provided in the housing 20 in such a way that the side plate can move in the recession, both of which are provided parallel to the turbine shaft; a pushing means 116, 150 to push the side plate toward the mounting plate 102; and a limiting means 108 to limit the movement of the side plate parallel to the turbine shaft toward the mounting plate 102.

Full Text

The present invention relates to a variable-capacity turbocharger which controls the opening degree of nozzle vanes. This invention concerns a variable-capacity turbocharger. More specifically, it concerns an improvement of a nozzle unit for supplying exhaust gases to a turbine of the turbocharger. 1. Description of the Related Art A turbocharger is an effective means to increase the output of an internal combustion engine. A turbine is rotated by the exhaust gas from the engine, and a compressor mounted on the same shaft as the turbine pressurizes the air supplied to the engine. Turbochargers are currently installed in a variety of engines. However, the flow rate of the exhaust gas varies with the speed of the engine's revolution. The flow rate of the exhaust gas which is actually supplied from the engine will not always be that needed to produce the ideal operating conditions for the supercharger. To rectify this situation and allow the turbocharger's capacity to be used to its best advantage, a variable-capacity turbocharger has been developed. In a variable-capacity turbocharger, the flow of the exhaust gas in the turbine compartment is regulated according to the operating state of the internal combustion engine. This sort of variable-capacity turbocharger has a number of nozzle vanes on the nozzle unit of the turbine, which is inside a housing. FIG. 8 shows a partial cross section of the nozzle unit in a variable-capacity turbocharger belonging to the prior art. In FIG. 8, turbine 228 is supported by bearings in a main housing of the variable-capacity turbocharger in such a way that it is free to rotate. The exhaust gas from the internal combustion engine flows into housing 220 through an intake port of the variable-capacity turbocharger. It is supplied to turbine 228 by way of scroll channel 226 which is formed in housing 220 and nozzle unit 210 which forms the inlet to the turbine 228. The exhaust gas supplied to turbine 228 is then exhausted through the exhaust port after it has driven the turbine 228. Nozzle unit 210 comprises mounting plate 202, which is fixed to housing 220, and side plate 206, which is placed opposite mounting plate 202. A number of nozzle vanes 204 are placed at equal intervals along the circumference between the two plates. Side plate 206 is fixed to mounting plate 202 by supporting bolt 208, which goes through the plate 206. Nozzle vanes 204 have a shaft portion. They are mounted on mounting plate 202 in such a way that they are free to rotate with the shaft portion. to the turbine shaft toward the side plate. The spring plate is engaged with and fixed to the round projection. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a lateral view of the exterior of a variable-capacity turbocharger in which this invention is implemented. Figure 2 is a cross section of the turbine compartment in the first preferred embodiment. Figure 3 is a partially cut away frontal view of the variable-capacity turbocharger in Figure 1. Figure 4 is an enlargement of a portion of Figure 3. It shows the transmission mechanism which transmits the action of the actuator to the link plate and the elements which link the two. Figure 5 is a plan view of the link plate. Figure 6 is an exploded view of the transmission mechanism to transmit the action of the actuator to the link plate. Figure 7 is a cross section of the turbine compartment in the second preferred embodiment of this invention. Figure 8 is a partial enlarged cross section of a nozzle unit belonging to the prior art. In these drawings, 10 is turbine casing, 50 is actuator, 52 is rod, 54 is link member, 104 is nozzle vane, 106 is side plate, 112 is link plate, 116 is spring plate, 114 is lever, 120 is swinging member, 130 is bridge, 140 is roller, 150 is pressure? chamber. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this section we shall explain several preferred embodiments of this invention with reference to the appended drawings. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not clearly defined, the scope of the invention is not limited only to the parts shown, which are meant merely for the purpose of illustration. In this section we shall explain two preferred embodiments of the invention with reference to the appended drawings. Figure 1 illustrates the external appearance of a variable-capacity turbocharger 10 in which this invention has been implemented. Variable-capacity turbocharger 10 includes a housing, which comprises turbine housing 20, compressor housing 40 and main housing 30, which is between turbine housing 20 and compressor housing 40. Turbine housing 20 has an intake port 22 and an exhaust port 24. Compressor housing 40 has an intake port 44 and a discharge port 42. On the outside of the housings 20, 30 and 40 is actuator 50, which drives the nozzle vanes (to be explained shortly). Actuator 50 uses air pressure, or more specifically it uses the negative pressure of the air sucked into the internal combustion engine (not pictured) on which the variable-capacity turbocharger 10 is installed, to cause rod 52 to move forward and back. According to the present invention there is provided a variable-capacity turbocharger which controls the opening degree of nozzle vanes comprising: a turbine provided in a housing, which is free to rotate on a turbine shaft, a plurality of nozzle vanes arranged in nozzle units around said turbine in said housing, a link plate which rotates freely around said turbine provided in said housing, which is connected to said nozzle vanes by means of a plurality of levers, an actuator outside the housing, which is connected to said link plate through a transmission mechanism, wherein said nozzle unit has: a mounting plate fixed to the housing and a side plate installed in a recess provided in the housing, a pushing means to push said side plate toward said mounting plate, and a limiting means to limit the movement of said side plate parallel to the turbine shaft toward said mounting plate, characterized in that said pushing means to push said side plate is a pressure chamber created between said side plate and said recess. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 is a lateral view of the exterior of a variable- capacity turbocharger in which this invention is implemented. FIG. 2 is a cross section of a turbine compartment in the first preferred embodiment. FIG. 3 is a partially cut away frontal view of the variable-capacity turbocharger in FIG. 1. FIG. 4 is an enlargement of a portion of FIG. 3. It shows a transmission mechanism which transmits the action of an actuator to a link plate and the elements which link the two. FIG. 5 is a plan view of the link plate. FIG. 6 is an exploded view of the transmission mechanism to transmit the action of the actuator to the link plate. FIG. 7 is a cross section of the turbine compartment in the second preferred embodiment of this invention. FIG. 8 is a partial enlarged cross section of a nozzle unit belonging to the prior art. In these drawings, 10 is a turbine casing, 50 is an actuator, 52 is a rod, 54 is a link member, 104 is a nozzle vane, 106 is a side plate, 112 is a link plate, 116 is a spring plate, 114 is a lever, 120 is a swinging member, 130 is a bridge, 140 is a roller, and 150 is a pressure chamber. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this section we shall explain several preferred embodiments of this invention with reference to the appended drawings. The scope of the invention is not limited only to the parts shown, along with the shapes, relative positions and other aspects of the parts described in the embodiments, which are meant merely for the purpose of illustration. In this section we shall explain two preferred embodiments of the invention with reference to the appended drawings. FIG. I illustrates the external appearance of a variable-capacity turbocharger 10 in which this invention has been implemented. Variable-capacity turbocharger 10 includes a housing, which comprises turbine housing 20, compressor housing 40 and main housing 30, which is between turbine housing 20 and compressor housing 40. Turbine housing 20 has an intake port 22 and an exhaust port 24. Compressor housing 40 has an intake port 44 and a discharge port 42. posed surfaces are parallel and slide against each other. As can be seen in Figure 6, when the transmission mechanism is assembled, the locking unit is formed when cut-away portion 138 goes into roller 140, which is mounted on pin 126 of swinging member 120. Bridge 130 may be made of a metallic material, for example, austenitic stainless steel. As shown in Figure 6, roller 140 is roughly cylindrical, with the diameter of it's opening slightly larger than the exterior diameter of pin 126. The exterior diameter of the roller is slightly smaller than the gap between the sliding surfaces 138 of bridge 130. Roller 140 may be made of a metallic material, for example, martensite stainless steel. In this section we shall explain how this embodiment operates. When the internal combustion engine operates, as shown in Figure 1, a negative intake pressure is created according to its rate of revolution and the openness of its throttle, and then the pressure is controlled by a magnetic valve to transmit it to the actuator 50. The actuator 50 operates according to this pressure. Rod 52 moves forward and back in the axial direction •'to the right and left in Figure 1) according to the magnitude of the negative intake pressure. When rod 52 operates, link member 54 rotates on shaft 124 of swinging member 120 in response. As can be seen in Figure 1, link member 54, which is shown by solid lines, is in contact with bolt 56a on the top of stop 56. At this point nozzle vanes 104 are in the open position, the position which produces the maximum nozzle opening. When the engine is operating at low r.p.m., or the throttle is only slightly open, actuator 50 draws back rod 52. As rod 52 draws as far back as it can go, link member 54 moves into a position in which it is in contact with bolt 56b on the lower portion of stop 56, as shown by the dotted lines. At this point nozzle vanes 104 are in the position which produces the smallest nozzle opening. In this way the linear movement of rod 52 is converted by Link member 54 into the swinging motion of swinging member 120. Pin 126 of member 120 moves in an arc around axis 0 of shaft 122 as shown in Figures 4 and 5. At this point pin 126 and roller 140 are in cut-away portion 138 in bridge 130, and the pin is between roller 140 and surface 138a. It slides upward and downward against bridge 130 in the relationship shown in Figure 6, i.e., it slides along the axis of rotation of turbine 28. At the same time link plate 112 rotates around the circumference of boss 102a on mounting plate 102, with the rotary axis of turbine 18 as its center. When link plate 112 rotates, lever 114, which is connected to link plate 112, rotates along with nozzle vanes 104 with shaft 104a of vanes 104 as its center. As has been discussed, in prior art designs a space is provided between side plate 106 and nozzle vanes 104 to accommodate the thermal deformation of side plate 106. For this reason prior art designs allowed a portion of the exhaust gas which At the base of nozzle vanes 104 is shaft portion 104a, which is mounted to mounting plate 102 so that portion 104a is free to rotate the vanes between the open and closed positions. As shown in FIGS. 3 and 4, an end 104b of each shaft portion 104a of nozzle vane assembly 104 goes through mounting plate 102 in the axial direction. The shafts are connected to various levers 114 which correspond to the nozzle vanes. (See FIGS. 3 and 4). The nozzle vane 104 rotates via nozzle shaft 104a according to the rotation of lever 114. Each lever 114 has a hole 114b to receive the end 104b of one of the shaft portions 104a and a boss or shaft portion 114a on the side opposite the hole 114b. The shaft 114a of lever 114 can slide within an oblong hole 112d provided at regular intervals along the circumference of link plate 112. As shown in FIG. 2, there is a cylindrical boss 102a on the side of mounting plate 102 opposite nozzle unit 100. The annular link plate 112 (See FIG. 5) is mounted to the boss 102a so that it is free to rotate on the rotational axis of turbine 28. Link plate 112 has a series of oblong holes 112d at regular intervals along its circumference to receive the shaft portions 114a of levers 114. Further, link plate 112 has, on the same surface, a trapezoidal elongated portion 112a on one side. The end of the elongated portion 112a is divided into two portions to form locking arms 112c. The two arms 112c form a rectangular recess 112b. The variable-capacity turbocharger 10 of this embodiment also has a transmission mechanism to transmit "trre""action of the actuator 50 to link plate 112 as shown in FIGS. I and 2. The transmission mechanism includes rod 52 of actuator 50, link member 54 (see FIG. 1), which is connected to the end of rod 52 by pin 50a, swinging member 120 (see FIGS. 2 and 6), which is connected to the link member 54, and roller 140 and bridge 130, which are between member 120 and link plate 112, and which serve to connect the transmission mechanism to link plate 112. As can be seen in FIG. 6, swinging member 120 comprises arm 122, shaft 124, which extends along a given axis O from one end of arm 122, and is supported by turbine housing 20 through sleeve 118 in such a way that it can freely rotate, connector 128, which is on the end of shaft 124 and coaxial with it, and connected to link member 54 in such a way that it cannot move relative to the link member, and pin 126, which extends from the side of arm 122 opposite shaft 124 and is parallel to that shaft. Swinging member 120 may be made of a metallic material, for example, stainless steel. Ideally, it should be formed of a single piece of austenitic stainless steel. Swinging member 120, arm 122, shaft 124, connector 128 and pin 126 may be formed separately and welded together. Bridge 130 comprises two flat plates 132, which are positioned parallel to each other with a slight gap between them, and center unit 134, which connects the two plates 132. At the center unit 134 provided between the two plates 132 is a groove 136 in which the locking arms 112c of link plate 112 engage. Part of bridge 130, including center unit 134, is removed to the middle of the bridge to form cut-away portion 138. The two opposed surfaces are parallel and slide against each other. As can be seen in FIG. 6, when the transmission mechanism is assembled, the locking unit is formed when cutaway portion 138 goes into roller 140, which is mounted on pin 126 of swinging member 120. Bridge 130 may be made of a metallic material, for example, austenitic stainless steel. As shown in FIG. 6, roller 140 is roughly cylindrical, with the diameter of it's opening slightly larger than the exterior diameter of pin 126. The exterior diameter of the roller is slightly smaller than the gap between the sliding surface 138 of bridge 130. Roller 140 may be made of a metallic material, for example, martensite stainless steel. In this section we shall explain how this embodiment operates. When the internal combustion engine operates, as shown in FIG. 1, a negative intake pressure is created according to its rate of revokua©« arrd the openness of its throttle, and then the pressure is controlled by a magnetic valve rVO to transmit it to the actuator 50. The actuator 50 operates according te this ft pressure. Rod 52 moves forward and back in the axial direction (to the right and left in FIG. 1) according to the magnitude of the negative intake pressure. When rod 52 operates, link member 54 rotates on shaft 124 of swinging member 120 in response. As can be seen in FIG. 1, link member 54, which is shown by solid lines, is in contact with bolt 56a on the top of stop 56. At this point nozzle vanes 104 are in the open position, the position which produces the maximum nozzle opening. When the engine is operating at low r.p.m., or the throttle is only slightly open, actuator 50 draws back rod 52. As rod 52 draws as far back as it can go, link member 54 moves into a position in which it is in contact with bolt 56b on the lower portion of stop 56, as shown by the dotted lines. At this point nozzle vanes 104 are in the position which produces the smallest nozzle opening. In this way the linear movement of rod 52 is converted by link member 54 into the swinging motion of swinging member 120. Pin 126 of member 120 moves in an arc around axis O of shaft 122 as shown in FIGS. 4 and 5. At this point pin 126 and roller 140 are in cut-away portion 138 in bridge 130, and the pin is between roller 140 and a surface. It slides upward and downward against bridge 130 in the relationship shown in FIG. 6, i.e., it slides along the axis of rotation of turbine 28. At the same time link plate 112 rotates around the circumference of boss 102a on mounting plate 102, with the rotary axis of turbine 28 as its center. When link plate 112 rotates, lever 114, which is connected to link plate 112, rotates along with nozzle vanes 104 with shaft 104a of vanes 104 as its center. As has been discussed, in prior art designs a space is provided between side plate 106 and nozzle vanes 104 to accommodate the thermal deformation of side plate 106. For this reason prior art designs allowed a portion of the exhaust gas which should have gone into the channel between scroll channel 26 and nozzle vanes 104 to bypass the area between side plate 106 and nozzle We Claim: 1. A variable-capacity turbocharger which controls the opening degree of nozzle vanes (104) comprising: a turbine (28) provided in a housing (20), which is free to rotate on a turbine shaft (32), a plurality of nozzle vanes (104) arranged in nozzle units (100) around said turbine (28) in said housing (20), a link plate (112) which rotates freely around said turbine (28) provided in said housing (20), which is connected to said nozzle vanes (104) by means of a plurality of levers (114), an actuator (50) outside the housing (20), which is connected to said link plate (112) through a transmission mechanism, wherein said nozzle unit (100) has: a mounting plate (102) fixed to the housing (20) and a side plate (106) installed in a recess (20a) provided in the housing (20), a pushing means to push said side plate (106) toward said mounting plate (102), and a limiting means to limit the movement of said side plate (106) parallel to the turbine shaft (32) toward said mounting plate (102), characterized in that said pushing means to push said side plate (106) is a pressure chamber (150) created between said side plate (106) and said recess (20a). 2. A variable-capacity turbocharger as claimed in claim 1, wherein said pushing means to push said side plate is a spring plate mounted between said side plate and said recession. 3. A variable-capacity turbocharger as claimed in claim 2, wherein said side plate (106) has a doughnut shape whose center is the turbine shaft (32), said recess (20a) has a diameter greater than the diameter of said side plate (106), said recess (20a) has on the inner surface a round projection which protrudes parallel to the turbine shaft (32) toward said side plate (106), and a spring plate (116) is engaged with and fixed to said round projection. 4. A variable-capacity turbocharger which controls the opening degree of nozzle vanes substantially as herein described with reference to the accompanying drawings.

Documents:

61-del-2001-abstract.pdf

61-del-2001-claims.pdf

61-del-2001-complete specification (granded).pdf

61-del-2001-correspondence-others.pdf

61-del-2001-correspondence-po.pdf

61-del-2001-description (complete).pdf

61-del-2001-drawings.pdf

61-del-2001-form-1.pdf

61-del-2001-form-13.pdf

61-del-2001-form-19.pdf

61-del-2001-form-2.pdf

61-del-2001-form-3.pdf

61-del-2001-form-5.pdf

61-del-2001-pa.pdf

61-del-2001-petition-137.pdf

61-del-2001-petition-138.pdf