Turbocharger

Abstract

The present invention relates to a turbocharger. The turbocharger includes a turbine impeller, a turbine housing, a bearing housing, a compressor housing, a sealing plate, a variable nozzle mechanism, a through-shaft, and a spring member. The variable nozzle mechanism is located in the turbine housing and adjusts the amount of exhaust gas flowing toward the turbine impeller. The through-shaft extends through the bearing housing and is connected to the variable nozzle mechanism. The spring member pushes the through-shaft toward the compressor housing. The bearing housing and the sealing plate define a cooling chamber through which a coolant flows. The spring member is located in the cooling chamber.

Description

Technical Field

[0001] The invention relates to a turbocharger. Background Art

[0002] The turbocharger described in Japanese Unexamined Patent Application Publication No. 2020-076328 (JP 2020-076328 A) includes a turbine housing, a bearing housing, a sealing plate, a compressor housing, and a turbine impeller. The turbine housing accommodates the turbine impeller. The bearing housing is fixed to the turbine housing. The compressor housing is fixed to the bearing housing. The sealing plate is located between the bearing housing and the compressor housing.

[0003] The turbocharger described in JP 2020-076328 A also includes a variable nozzle mechanism, a through shaft and a spring member. The variable nozzle mechanism is located in the turbine housing. The variable nozzle mechanism adjusts the amount of exhaust gas flowing toward the turbine impeller. The through shaft extends through the bearing housing. The first end of each of the through shafts is connected to the variable nozzle mechanism. The second end of the through shaft is located between the bearing housing and the sealing plate. The spring member is installed at the second end of the through shaft. The spring member pushes the through shaft toward the compressor housing. With this arrangement, the variable nozzle mechanism is positioned in the turbine housing. Summary of the invention

[0004] In a turbocharger as described in JP 2020-076328 A, heat is transferred from the turbine housing to the sealing plate via the bearing housing and the through-shaft. Therefore, it is preferable to provide a cooling chamber through which a coolant flows for cooling the through-shaft, the sealing plate, etc. However, in order to provide the cooling chamber, the sealing plate and the compressor housing must be designed to be large enough to define the size of the cooling chamber, which may result in an increase in the size of the turbocharger.

[0005] One aspect of the present invention relates to a turbocharger, which includes a turbine impeller, a turbine housing, a bearing housing, a compressor housing, a sealing plate, a variable nozzle mechanism, a through shaft, and a spring member. The turbine impeller is configured to rotate by the flow of exhaust gas. The turbine housing accommodates the turbine impeller. The bearing housing is fixed to the turbine housing. The compressor housing is fixed to the bearing housing. The sealing plate is located between the bearing housing and the compressor housing. The variable nozzle mechanism is located in the turbine housing and is configured to adjust the amount of exhaust gas flowing toward the turbine impeller. The through shaft extends through the bearing housing and is connected to the variable nozzle mechanism. The spring member is configured to push the through shaft toward the compressor housing. The bearing housing and the sealing plate are configured to define a cooling chamber through which a coolant flows. The spring member is located in the cooling chamber.

[0006] In the turbocharger according to the above aspect, the space for accommodating the spring member can be effectively utilized as a cooling chamber, thereby eliminating the need to newly provide a cooling chamber in the compressor housing and the sealing plate. Therefore, the turbocharger is less likely or less likely to be large-sized as compared with the case where the cooling chamber and the space for accommodating the spring member are separately provided.

[0007] In the turbocharger according to the above aspect, the spring member may be a helical wave spring. Typically, the axial dimension of the helical wave spring is, for example, smaller than the axial dimension of the coil spring. Also, typically, for example, a change in force according to the elastic deformation amount of the helical wave spring is smaller than a change in force of the disc spring; therefore, the force applied to the object can be easily adjusted. Therefore, by the above arrangement, it is possible to suppress an increase in the size of the turbocharger in the axial direction of the helical wave spring while ensuring a sufficiently large force applied from the helical wave spring to the through-shaft.

[0008] In the turbocharger as described above, a plurality of through-shafts may be arranged on a circumference around the rotation axis of the turbine impeller, and the spiral wave spring may surround the rotation axis and be configured to push all through-shafts toward the compressor housing. Then, all through-shafts may be positioned to be equally spaced in a circumferential direction around the rotation axis.

[0009] In the turbocharger thus constructed, all through shafts can be pushed out by a single helical wave spring; therefore, an increase in the number of components is suppressed. Moreover, since a large diameter can be ensured as the diameter of the helical wave spring, sufficient elastic force of the helical wave spring can be easily ensured.

[0010] In the turbocharger according to the above aspect, the bearing housing may include a through hole through which the through shaft is inserted, and a sealing member may be located between the outer peripheral surface of the through shaft and the inner peripheral wall of the through hole, the sealing member sealing the gap between the through shaft and the through hole. By this configuration, the amount of exhaust gas flowing from the turbine housing to the compressor housing via the gap between the outer peripheral surface of the through shaft and the inner peripheral wall of the through hole can be reduced.

[0011] In the turbocharger configured as described above, the bearing housing may be configured to define a retaining space that retains the sealing member, and the retaining space may be communicated with a cooling chamber. The cooling chamber may have a substantially annular shape. With the turbocharger configured as described above, the retaining space is communicated with the cooling chamber, so that the sealing member is easily cooled by heat exchange with a coolant flowing through the cooling chamber.

[0012] In the turbocharger constructed as described above, a retaining plate holding the sealing member can be mounted on the bearing housing, and the sealing member can be sandwiched between the inner wall of the retaining space and the end face of the retaining plate. With the turbocharger constructed as described above, the sealing member abuts against the retaining plate, thereby preventing the sealing member from shifting closer to the compressor housing.

[0013] In the turbocharger according to the above aspect, the compressor housing may house the compressor impeller connected to the turbine impeller, and at least a portion of the cooling chamber may be located outside the compressor impeller in a radial direction perpendicular to the rotation axis of the turbine impeller. With the turbocharger thus configured, the temperature of the portion of the sealing plate located radially outside the compressor impeller is less likely or less likely to increase due to heat exchange between the portion of the sealing plate located radially outside the compressor impeller and the coolant flowing through the cooling chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0015] Figure 1 is a schematic view of an internal combustion engine in which a turbocharger as one embodiment of the present invention is installed;

[0016] Figure 2 is a cross-sectional view of a turbocharger;

[0017] Figure 3 yes Figure 2 An enlarged cross-sectional view of;

[0018] Figure 4 It is along Figure 2 A cross-sectional view taken along line IV-IV in FIG. 1 ; and

[0019] Figure 5 It is along Figure 4 A cross-sectional view taken along line VV in FIG. DETAILED DESCRIPTION

[0020] refer to Figures 1 to 5 , an embodiment as an example of the present invention will be described. First, a schematic configuration of an internal combustion engine 10 of a vehicle in which a turbocharger 20 of the present invention is used will be described.

[0021] like Figure 1As shown, the internal combustion engine 10 includes an intake passage 11, a cylinder 12, an exhaust passage 13, and a turbocharger 20. The intake passage 11 allows intake air to be introduced from the outside of the internal combustion engine 10. The cylinder 12 is connected to the intake passage 11. In the cylinder 12, fuel and intake air are mixed and burned. The exhaust passage 13 is connected to the cylinder 12. The exhaust passage 13 allows exhaust gas to be discharged from the cylinder 12.

[0022] The turbocharger 20 includes a compressor housing 30 , a sealing plate 40 , a bearing housing 50 , a turbine housing 60 , a compressor impeller 70 , a connecting shaft 80 , and a turbine impeller 90 .

[0023] The compressor housing 30 is installed in the intake passage 11. The turbine housing 60 is installed in the exhaust passage 13. The bearing housing 50 is fixed to the compressor housing 30 and the turbine housing 60, respectively, and connects the compressor housing 30 with the turbine housing 60. Therefore, the turbocharger 20 extends across the intake passage 11 and the exhaust passage 13. Although the sealing plate 40 is located between the bearing housing 50 and the compressor housing 30, Figure 1 The sealing plate 40 is not shown.

[0024] The turbine housing 60 accommodates a turbine impeller 90. The bearing housing 50 accommodates a connecting shaft 80. The bearing housing 50 rotatably supports the connecting shaft 80 via a bearing (not shown). A first end of the connecting shaft 80 is connected to the turbine impeller 90. The compressor housing 30 accommodates a compressor impeller 70. The compressor impeller 70 is connected to a second end of the connecting shaft 80. That is, the compressor impeller 70 is connected to the turbine impeller 90 via the connecting shaft 80.

[0025] When the turbine wheel 90 is rotated by the exhaust gas flow inside the turbine housing 60, the compressor wheel 70 is rotated along with the turbine wheel 90 via the connecting shaft 80. By the compressor wheel 70 being thus rotated, the intake air in the compressor housing 30 is compressed.

[0026] Next, the specific configuration of the turbocharger 20 will be described. In the following description, the direction along the rotation axis 90A as the rotation center of the turbine impeller 90 will be abbreviated as the "rotation axis direction". Also, the direction perpendicular to the rotation axis 90A will be abbreviated as the "radial direction".

[0027] like Figure 2 As shown, the turbine housing 60 includes an arcuate portion 60A and a cylindrical portion 60B. The cylindrical portion 60B has a generally cylindrical shape. The cylindrical portion 60B generally extends along a rotation axis 90A as a rotation center of the turbine impeller 90. The arcuate portion 60A extends around the outer periphery of the cylindrical portion 60B and has a generally circular arc shape.

[0028] The turbine housing 60 defines a vortex passage 61, an accommodating space 62, and a discharge passage 63 as spaces through which exhaust gas flows. The vortex passage 61 is located within the arc-shaped portion 60A and the cylindrical portion 60B. The vortex passage 61 extends in the circumferential direction to surround the turbine impeller 90. The upstream end of the vortex passage 61 is connected to the exhaust passage 13 on the upstream side of the turbine housing 60. The downstream end of the vortex passage 61 is connected to the accommodating space 62. The accommodating space 62 is a portion of the inner space of the cylindrical portion 60B in which the turbine impeller 90 is located. The accommodating space 62 is connected to the discharge passage 63. The discharge passage 63 is a portion of the inner space of the cylindrical portion 60B, which includes an end portion opposite to the bearing housing 50, i.e. Figure 2 The downstream end of the exhaust passage 63 is connected to the exhaust passage 13 on the downstream side of the turbine casing 60 .

[0029] The turbocharger 20 includes a variable nozzle mechanism 110. The variable nozzle mechanism 110 is located in the vortex passage 61. The variable nozzle mechanism 110 includes a support member 111 and a plurality of nozzles 112. The support member 111 has a generally annular shape surrounding the turbine impeller 90. The support member 111 includes three insertion holes 111A. The three insertion holes 111A extend through the support member 111 in the direction of the rotation axis. The three insertion holes 111A are located on a circumference including a center on the rotation axis 90A. The three insertion holes 111A are equiangularly spaced in the circumferential direction around the rotation axis 90A. More specifically, the three insertion holes 111A are arranged at intervals of 120 degrees. Figure 2 In the figure, only one set of insertion holes 111A and their related structures are illustrated.

[0030] The support member 111 supports the nozzles 112. The nozzles 112 are positioned around the turbine wheel 90. The nozzles 112 are operated by an actuator (not shown) so that their orientation relative to the turbine wheel 90 is changed. As a result, the direction and amount of exhaust gas flowing to the turbine wheel 90 are adjusted, and the rotation speed of the turbine wheel 90 is controlled.

[0031] The bearing housing 50 includes a housing body 50A, a first flange 50B and a second flange 50C. The housing body 50A is a solid, substantially cylindrical body. The first flange 50B protrudes from the outer peripheral surface of the housing body 50A. The first flange 50B is located on the end of the housing body 50A closer to the turbine housing 60. The first flange 50B is fixed to the arcuate portion 60A of the turbine housing 60. The second flange 50C protrudes from the outer peripheral surface of the housing body 50A. The second flange 50C protrudes from the entire circumference of the housing body 50A and has a substantially annular shape. The second flange 50C is located on the end of the housing body 50A closer to the compressor housing 30.

[0032] like Figure 2As shown, the bearing housing 50 defines an insertion hole 52, a recessed portion 53 and three through holes 54. The insertion hole 52 extends through the housing body 50A in the rotation axis direction. The insertion hole 52 is located on the central axis of the housing body 50A. The connecting shaft 80 is inserted through the insertion hole 52.

[0033] like Figure 3 As shown, the recessed portion 53 is recessed from the end surface of the housing body 50A closer to the compressor housing 30 toward the turbine housing 60. The recessed portion 53 has a substantially annular shape around the rotation axis 90A. When viewed in the rotation axis direction, the recessed portion 53 is located in a portion overlapping with the three insertion holes 111A of the variable nozzle mechanism 110.

[0034] like Figure 4 As shown, the bearing housing 50 defines an inlet hole 56 and an outlet hole 57. Figure 5 As shown, the introduction hole 56 leads to the bottom of the recessed portion 53. The opening of the introduction hole 56 is located near the outer edge of the recessed portion 53. The introduction hole 56 is connected to an introduction pipe (not shown) connected to the bearing housing 50. The introduction hole 56 allows the coolant to be introduced into the recessed portion 53. Figure 4 As shown, the drain hole 57 opens to a portion of the bottom of the recessed portion 53 near the introduction hole 56. The opening of the drain hole 57 is located near the outer edge of the recessed portion 53. The drain hole 57 is connected to a drain pipe (not shown) connected to the bearing housing 50. The drain hole 57 allows the coolant introduced into the recessed portion 53 to be discharged. An example of the coolant is cooling water.

[0035] like Figure 2 As shown, each of the through holes 54 extends in the rotation axis direction from the bottom of the recessed portion 53 to the end surface of the housing body 50A closer to the turbine housing 60. When viewed in the rotation axis direction, the three through holes 54 are located in the same portion as the three insertion holes 111A of the variable nozzle mechanism 110. Each through hole 54 has a substantially circular shape when viewed in the rotation axis direction.

[0036] like Figure 3 As shown, the through hole 54 includes a holding space 54A and a connecting space 54B. The holding space 54A is a portion of the through hole 54, which includes an end portion closer to the compressor housing 30. That is, the holding space 54A is communicated with the recessed portion 53. The connecting space 54B is a space of the through hole 54 other than the holding space 54A. The inner diameter of the connecting space 54B is substantially equal to the inner diameter of the insertion hole 111A of the variable nozzle mechanism 110, and is smaller than the inner diameter of the holding space 54A.

[0037] like Figure 2As shown, the sealing plate 40 is fixed to the end surface of the housing body 50A of the bearing housing 50 that is closer to the compressor housing 30. The sealing plate 40 has a substantially circular plate form. The outer diameter of the sealing plate 40 is larger than the outer diameter of the housing body 50A of the bearing housing 50, and smaller than the outer diameter of the second flange 50C of the bearing housing 50. The sealing plate 40 is fixed to the substantially central portion of the housing body 50A of the bearing housing 50 by bolts (not shown).

[0038] The sealing plate 40 includes an insertion hole 41 and a recessed portion 42. The insertion hole 41 extends through the sealing plate 40 in the direction of the rotation axis. When viewed in the direction of the rotation axis, the insertion hole 41 is substantially located in the middle of the sealing plate 40. The connecting shaft 80 is inserted through the insertion hole 41. The recessed portion 42 is recessed from the end surface of the sealing plate 40 closer to the bearing housing 50 toward the compressor housing 30. The recessed portion 42 has a substantially annular shape around the rotation axis 90A. When viewed in the direction of the rotation axis, the recessed portion 42 is located in the same portion as the recessed portion 53 of the bearing housing 50. Therefore, in this embodiment, the sealing plate 40 and the bearing housing 50 cooperate with each other to define the space between the recessed portion 42 of the sealing plate 40 and the recessed portion 53 of the bearing housing 50 as a cooling chamber 20A. The entire area of ​​the cooling chamber 20A is located radially outside the compressor impeller 70. Since the recessed portion 42 of the sealing plate 40 and the recessed portion 53 of the bearing housing 50 have a substantially annular shape, the cooling chamber 20A has a substantially annular shape.

[0039] like Figure 4 As shown, the sealing plate 40 includes a fixing protrusion 46 and a partition 47. The fixing protrusion 46 protrudes radially inward from the inner peripheral surface of the recessed portion 42 on the radial outer side. The fixing protrusion 46 is located near one of the three through holes 54 of the bearing housing 50 when viewed in the rotation axis direction.

[0040] like Figure 5 As shown, the partition 47 protrudes from the bottom of the recessed portion 42 toward the turbine housing 60. The distal end of the partition 47 is positioned close to the bottom of the recessed portion 53 of the bearing housing 50. Figure 4 As shown, the partition 47 is located between the introduction hole 56 and the discharge hole 57 of the bearing housing 50 when viewed in the rotation axis direction.

[0041] like Figure 3 As shown, the turbocharger 20 includes a radially inner seal 171 and a radially outer seal 172. The radially inner seal 171 has a generally annular shape around the rotation axis 90A. The radially inner seal 171 is located between the housing body 50A of the bearing housing 50 and the sealing plate 40. The radially inner seal 171 is located radially inside the cooling chamber 20A. Therefore, the radially inner seal 171 seals the radially inner part of the cooling chamber 20A.

[0042] The radially outer seal 172 has a generally annular shape around the rotation axis 90A. The radially outer seal 172 is located between the second flange 50C of the bearing housing 50 and the seal plate 40. The radially outer seal 172 is located radially outside the cooling chamber 20A. Therefore, the radially outer seal 172 seals the radially outer part of the cooling chamber 20A.

[0043] like Figure 2 As shown, the compressor housing 30 includes a cylindrical portion 30A and an arcuate portion 30B. The cylindrical portion 30A has a substantially cylindrical shape. The cylindrical portion 30A extends along the rotation axis 90A. The arcuate portion 30B extends around the outer periphery of the cylindrical portion 30A and has a substantially circular arc shape.

[0044] The compressor housing 30 defines an introduction passage 31, an accommodation space 32, a connection passage 33, and a swirl passage 34 as spaces through which intake air flows. The introduction passage 31 is a portion of the inner space of the cylindrical portion 30A, which includes an end portion opposite to the sealing plate 40, i.e. Figure 2 The upstream end of the introduction passage 31 is connected to the intake passage 11 on the upstream side of the compressor housing 30. The downstream end of the introduction passage 31 is connected to the accommodation space 32. The accommodation space 32 is a part of the internal space of the cylindrical portion 30A except the introduction passage 31. The accommodation space 32 accommodates the compressor impeller 70.

[0045] The vortex passage 34 is located in the arc portion 30B. The vortex passage 34 extends in the circumferential direction to surround the compressor impeller 70. The downstream end of the vortex passage 34 is connected to the intake passage 11 on the downstream side of the compressor housing 30. The connecting passage 33 is located between the cylindrical portion 30A and the sealing plate 40 of the compressor housing 30, and is defined by the cylindrical portion 30A and the sealing plate 40. The connecting passage 33 is located between the accommodating space 32 and the vortex passage 34, and connects the accommodating space 32 with the vortex passage 34. When viewed in the direction of the rotation axis, the connecting passage 33 has a substantially annular shape.

[0046] The compressor housing 30 defines a cooling passage 36 as a space through which a coolant flows. The cooling passage 36 is located in a portion of the cylindrical portion 30A close to the connecting passage 33. The cooling passage 36 has a substantially annular shape surrounding the compressor impeller 70. The cooling passage 36 is connected to a supply passage (not shown) connected to the compressor housing 30. Then, the coolant flows into the cooling passage 36 via the supply passage. As a result, the cylindrical portion 30A and the like are cooled by heat exchange with the coolant flowing through the cooling passage 36.

[0047] like Figure 3As shown, the turbocharger 20 includes three through-shafts 120, a sealing member 130, a retaining plate 140, a spring member 150, and a fixing member 160. Each of the through-shafts 120 is inserted through a corresponding one of the through holes 54. Therefore, the three through-shafts 120 are located on a circumference around the rotation axis 90A. In addition, the three through-shafts 120 are positioned to be equally spaced in a circumferential direction around the rotation axis 90A.

[0048] like Figure 2 and Figure 3 As shown, the through shaft 120 includes a head 121, a large diameter portion 122, a small diameter portion 123, and a fixed end portion 124. The large diameter portion 122 has a solid, substantially cylindrical shape. The outer diameter of the large diameter portion 122 is substantially equal to the inner diameter of the connection space 54B of the through hole 54 of the bearing housing 50. The large diameter portion 122 is inserted through the through hole 54 of the bearing housing 50 and the insertion hole 111A of the variable nozzle mechanism 110.

[0049] The head 121 is located at a first end of the large diameter portion 122. The head 121 has a substantially disk-like shape. The outer diameter of the head 121 is greater than the outer diameter of the large diameter portion 122. The head 121 is connected to the support member 111. That is, the through shaft 120 is connected to the variable nozzle mechanism 110.

[0050] like Figure 3 As shown, the small diameter portion 123 is located at the second end of the large diameter portion 122. The small diameter portion 123 has a solid, substantially cylindrical shape. The outer diameter of the small diameter portion 123 is smaller than the outer diameter of the large diameter portion 122.

[0051] The fixed end portion 124 is located at the end of the small diameter portion 123 opposite to the large diameter portion 122. The fixed end portion 124 has a substantially disc-like shape. The outer diameter of the fixed end portion 124 is larger than the outer diameter of the small diameter portion 123 and is substantially equal to the outer diameter of the large diameter portion 122.

[0052] The sealing member 130 is located in the retaining space 54A of the bearing housing 50. The sealing member 130 has a substantially annular shape surrounding the large diameter portion 122 of the through shaft 120. Therefore, the sealing member 130 seals the gap between the outer peripheral surface of the large diameter portion 122 of the through shaft 120 and the inner peripheral wall of the retaining space 54A of the through hole 54.

[0053] The retaining plate 140 is located on the bottom of the recessed portion 53 of the bearing housing 50. The retaining plate 140 has a generally annular shape around the rotation axis 90A. The retaining plate 140 covers the retaining space 54A of the through hole 54. The retaining plate 140 includes an insertion hole 141. The insertion hole 141 extends through the retaining plate 140 in the rotation axis direction. When viewed in the rotation axis direction, the insertion hole 141 is located in the same portion as the through hole 54. The inner diameter of the insertion hole 141 is smaller than the inner diameter of the retaining space 54A of the through hole 54, and is slightly larger than the outer diameter of the large diameter portion 122 of the through shaft 120. Therefore, the sealing member 130 is sandwiched between the end face of the retaining plate 140 closer to the turbine housing 60 and the inner wall of the retaining space 54A of the through hole 54 in the rotation axis direction. That is, the retaining plate 140 retains the sealing member 130. Also, the holding space 54A communicates with the cooling chamber 20A via a gap between the inner peripheral wall of the insertion hole 141 of the holding plate 140 and the outer peripheral surface of the large diameter portion 122 of the penetration shaft 120 .

[0054] The spring member 150 is located in the cooling chamber 20A. The spring member 150 has a generally annular shape around the rotation axis 90A. That is, the axial direction of the spring member 150 coincides with the direction of the rotation axis. The spring member 150 is positioned closer to the compressor housing 30 than the retaining plate 140. The spring member 150 is located radially inward of the through-shaft 120, that is, in a portion that is closer to the rotation axis 90A than the through-shaft 120. The end face of the spring member 150 that is closer to the turbine housing 60 abuts against the end face of the retaining plate 140 that is closer to the compressor housing 30. The spring member 150 is in a state where it is compressed in the direction of the rotation axis. An example of the spring member 150 is a helical wave spring. In Figure 3 and Figure 5 , the spring member 150 is illustrated in a simplified shape.

[0055] like Figure 3 As shown, the fixing member 160 is located in the cooling chamber 20A. Figure 4 As shown, the fixing member 160 includes an annular portion 161, three protrusions 162 and three fixing holes 165. Figure 4 and Figure 5 As shown, the fixing member 160 includes one radially inner upright portion 163 and three radially outer upright portions 164 .

[0056] like Figure 4As shown, the annular portion 161 has a substantially annular plate form around the rotation axis 90A. The inner diameter of the annular portion 161 is slightly smaller than the inner diameter of the spring member 150. The outer diameter of the annular portion 161 is slightly larger than the outer diameter of the spring member 150. When viewed in the rotation axis direction, the annular portion 161 is located in the same portion as the spring member 150. The end surface of the annular portion 161 closer to the turbine housing 60 abuts against the end surface of the spring member 150 closer to the compressor housing 30. Therefore, the spring member 150 pushes the fixing member 160 toward the compressor housing 30.

[0057] The protrusions 162 protrude radially outward from the outer edge of the annular portion 161. When viewed in the direction of the rotation axis, the protrusions 162 are spaced apart from each other in the circumferential direction and are located in the same portion as the three insertion holes 111A of the variable nozzle mechanism 110. Moreover, one of the three protrusions 162 is located near the fixing protrusion 46 of the sealing plate 40. When viewed in the direction of the rotation axis, the fixing protrusion 46 of the sealing plate 40 is located in the first circumferential direction (i.e., in the direction of the rotation axis). Figure 4 In the clockwise direction) is positioned adjacent to the above protrusion 162.

[0058] like Figure 4 As shown, the fixing holes 165 extend through the annular portion 161 and the protrusion 162 in the direction of the rotation axis. Each of the fixing holes 165 is in the form of a substantially elongated hole extending in the circumferential direction. Figure 4 The inner diameter of the portion positioned in the second circumferential direction (i.e., in the clockwise direction) is substantially equal to the outer diameter of the small diameter portion 123 of the through shaft 120 and is smaller than the outer diameter of the fixed end portion 124 of the through shaft 120. Figure 4 The inner diameter of the portion positioned in the first circumferential direction (in the counterclockwise direction) of the fixing hole 165 is larger than the inner diameter of the portion positioned in the first circumferential direction of the fixing hole 165, and is larger than the outer diameter of the fixing end portion 124 of the through shaft 120. The small diameter portion 123 of the through shaft 120 is inserted through the portion of the fixing hole 165 of the fixing member 160 positioned in the first circumferential direction.

[0059] like Figure 3 As shown, the fixed end portion 124 of the through-shaft 120 abuts against the end surfaces of the annular portion 161 and the protruding portion 162 of the fixed member 160 closer to the compressor housing 30. Moreover, as described above, the spring member 150 pushes the fixed member 160 toward the compressor housing 30. In this way, one spring member 150 pushes the three through-shafts 120 toward the compressor housing 30 via the fixed member 160. Therefore, the variable nozzle mechanism 110 is positioned in the vortex passage 34 of the turbine housing 60.

[0060] The fixing member 160 and the sealing plate 40 are installed in the following manner. First, the fixing end portion 124 of the through-shaft 120 is inserted through the fixing hole 165 of the fixing member 160, which is located in the second circumferential direction. Then, the fixing member 160 is fixed relative to the through-shaft 120 in the second circumferential direction (i.e., in the second circumferential direction). Figure 4 The small diameter portion 123 of the through shaft 120 is inserted through the fixing hole 165 of the fixing member 160, which is located in the first circumferential direction. In addition, the sealing plate 40 is fixed to the bearing housing 50 so that the fixing protrusion 46 of the sealing plate 40 is located in the first circumferential direction (i.e., in the direction of the rotation axis) when viewed in the direction of the rotation axis. Figure 4 As a result, when the sealing plate 40 is fixed to the bearing housing 50, the fixing protrusion 46 of the sealing plate 40 and the protrusion 162 of the fixing member 160 abut against each other, thereby preventing the fixing member 160 from being moved relative to the through shaft 120 in the first circumferential direction (i.e., in the clockwise direction). Figure 4 in a clockwise direction).

[0061] like Figure 3 As shown, the radially inner upright portion 163 protrudes from the inner edge of the annular portion 161 toward the turbine housing 60. The radially inner upright portion 163 extends over the entire length of the inner edge of the annular portion 161 and has a substantially annular shape. The radially inner upright portion 163 is located radially inside the spring member 150.

[0062] like Figure 5 As shown, the radially outer upright portion 164 protrudes from the outer edge of the annular portion 161 toward the turbine housing 60. Figure 4 As shown, each of the radially outer upright portions 164 is located between two protrusions 162 arranged in the circumferential direction as some portions of the outer edge of the annular portion 161. One of the three radially outer upright portions 164 is located close to the partition 47 of the sealing plate 40.

[0063] Next, the operation of this embodiment will be described. Figure 5 As indicated by the double-dot chain arrow in FIG. 1 , when the coolant is introduced into the cooling chamber 20A from the introduction hole 56 of the bearing housing 50, as shown in FIG. Figure 4 As indicated by the double-dot chain arrow in FIG. 1 , the coolant is directed by the partition 47 and the radially outer upright portion 164 in the first circumferential direction (i.e., in Figure 4 The coolant in the cooling chamber 20A then flows in the first circumferential direction. The coolant flowing through the cooling chamber 20A is discharged from the discharge hole 57 of the bearing housing 50. As a result, the through shaft 120, the sealing plate 40, etc. are cooled by heat exchange with the coolant flowing through the cooling chamber 20A.

[0064] Next, the effects of this embodiment will be described. (1) In the turbocharger 20, if a space accommodating the spring member 150 is provided separately from the cooling chamber 20A, the turbocharger 20 may be large-sized due to the presence of the space and the cooling chamber 20A.

[0065] In this regard, in this embodiment, as Figure 3 As shown, the spring member 150 is located in the cooling chamber 20A. Therefore, the space accommodating the spring member 150 can be effectively utilized as the cooling chamber 20A, which makes it unnecessary to newly provide a cooling chamber in the compressor housing 30 and the sealing plate 40. Therefore, the turbocharger 20 is less likely or less likely to be large-sized as compared with the case where the cooling chamber 20A and the space accommodating the spring member 150 are separately provided.

[0066] (2) In this embodiment, the spring member 150 is a helical wave spring. Typically, the axial dimension of the helical wave spring is smaller than the axial dimension of the coil spring, for example. Also, typically, for example, a change in force according to the amount of elastic deformation of the helical wave spring is smaller than a change in force of a disc spring; therefore, the force applied to an object can be easily adjusted. Therefore, in the turbocharger 20, it is possible to suppress an increase in the size of the turbocharger 20 in the axial direction of the spring member 150 (i.e., in the direction of the rotation axis) while ensuring a sufficiently large force applied from the spring member 150 to the through-shaft 120.

[0067] (3) In this embodiment, a single spring member 150 can push out all of the through-shafts 120; therefore, an increase in the number of components, such as due to the provision of two or more spring members 150, is prevented. Moreover, the spring member 150 around the rotation axis 90A can have a large diameter. As a result, it is easier to ensure a sufficiently large elastic force of the spring member 150, as compared with an arrangement in which the spring member 150 does not surround the rotation axis 90A.

[0068] (4) The sealing member 130 is located between the outer peripheral surface of the large diameter portion 122 of the penetration shaft 120 and the inner peripheral wall of the through hole 54 of the bearing housing 50. Therefore, the amount of exhaust gas that flows from the turbine housing 60 to the compressor housing 30 via the gap between the outer peripheral surface of the large diameter portion 122 of the penetration shaft 120 and the inner peripheral wall of the through hole 54 of the bearing housing 50 can be reduced.

[0069] (5) The sealing member 130 is located in the holding space 54A that is connected to the cooling chamber 20A. Since the accommodating space 54A is connected to the cooling chamber 20A, a portion of the coolant flowing through the cooling chamber 20A flows into the holding space 54A. Therefore, the sealing member 130 can be cooled by heat exchange with the coolant flowing into the holding space 54A.

[0070] (6) The sealing member 130 is sandwiched between the end surface of the retaining plate 140 closer to the turbine housing 60 and the inner wall of the retaining space 54A of the through hole 54 in the rotation axis direction. Therefore, the sealing member 130 abuts against the retaining plate 140, thereby preventing the sealing member 130 from shifting closer to the compressor housing 30. As a result, it is possible to prevent a situation in which the sealing effect of the sealing member 130 cannot be obtained due to the displacement of the sealing member 130 from the retaining space 54A to the cooling chamber 20A.

[0071] (7) In the turbocharger 20, when the intake air in the compressor housing 30 is compressed by the rotation of the compressor impeller 70, the temperature of the intake air in the connecting passage 33 increases. Then, as the temperature of the intake air in the connecting passage 33 increases, the temperature of the portion of the sealing plate 40 located radially outside the compressor impeller 70 may increase.

[0072] In this regard, the entire area of ​​the cooling chamber 20A is located radially outside the compressor impeller 70. Therefore, since the portion of the sealing plate 40 located radially outside the compressor impeller 70 exchanges heat with the coolant flowing through the cooling chamber 20A, the temperature of the portion of the sealing plate 40 located radially outside the compressor impeller 70 is less likely or unlikely to increase.

[0073] (8) In this embodiment, the radially inner standing portion 163 is located radially inward of the spring member 150. Therefore, the radial movement of the spring member 150 is restricted by the radially inner standing portion 163. Therefore, excessive displacement of the spring member 150 is prevented.

[0074] (9) In this embodiment, the partition 47 is present between the introduction hole 56 and the discharge hole 57. Then, the partition 47 and the radially outer upright portion 164 define a passage extending in the circumferential direction. Therefore, the coolant supplied to the cooling chamber 20A flows in the circumferential direction in the cooling chamber 20A and is likely to be dispersed throughout the cooling chamber 20A.

[0075] This embodiment can be modified and implemented as follows. This embodiment and the following modification examples can be combined within a technically compatible range.

[0076] Hereinafter, a modified example of the spring member will be described. In the illustrated embodiment, the spring member 150 is not limited to the spiral wave spring. For example, a disc spring and a spiral spring may be adopted as the spring member 150. Also with this arrangement, if the spring member 150 is located in the cooling chamber 20A, the turbocharger is less likely or less likely to be large-sized.

[0077] In the illustrated embodiment, the number of the spring member 150 is not necessarily one, but may be two or more. For example, one spring member 150 may be provided for one through-shaft 120.

[0078] Hereinafter, a modified example of the through-shaft will be described. In the illustrated embodiment, the positional relationship of the through-shaft 120 may be changed. For example, the through-shaft 120 may not necessarily be positioned to be equally spaced in the circumferential direction around the rotation axis 90A. Nevertheless, it is preferred that the through-shaft 120 be arranged at equal angles around the rotation axis 90A so that the variable nozzle mechanism 110 can be stably positioned by the through-shaft 120.

[0079] In the illustrated embodiment, the number of through-shafts 120 can be varied. For example, the number of through-shafts 120 may be two or less, or four or more. In addition, two or more through-shafts 120 may not necessarily be provided, but one through-shaft may be present.

[0080] Next, a modified example of the retaining plate will be described. In the illustrated embodiment, the retaining plate 140 can be omitted. For example, if the sealing member 130 is unlikely to be displaced in the direction of the rotation axis, the retaining plate 140 can be omitted. In a specific example, an annular groove can be provided in the outer peripheral surface of the through shaft 120, and the sealing member 130 can be installed in the groove, thereby suppressing the displacement of the sealing member 130.

[0081] Next, a modified example of the holding space will be described. In the illustrated embodiment, the holding space 54A may not be communicated with the cooling chamber 20A. In a specific example, through the gap between the inner peripheral wall of the insertion hole 141 of the holding plate 140 and the outer peripheral surface of the large diameter portion 122 of the through-shaft 120, even if the holding space 54A is not communicated with the cooling chamber 20A, the holding space 54A can exchange heat with the coolant flowing through the cooling chamber 20A through heat transfer via the holding plate 140.

[0082] Next, a modified example of the sealing member will be described. In the illustrated embodiment, the position of the sealing member 130 can be changed. For example, if the sealing member 130 can seal the gap between the outer peripheral surface of the large diameter portion 122 of the through shaft 120 and the inner peripheral wall of the holding space 54A of the through hole 54, the sealing member 130 can be located in the end of the through hole 54 closer to the turbine housing 60.

[0083] In the illustrated embodiment, the sealing member 130 may be omitted. When the gap between the outer peripheral surface of the large diameter portion 122 of the through shaft 120 and the inner peripheral wall of the holding space 54A of the through hole 54 is relatively small, the sealing member 130 may be omitted without causing a significant impact.

[0084] Next, a modified example of the cooling chamber will be described. In the illustrated embodiment, the shape of the cooling chamber 20A may be changed. For example, the cooling chamber 20A may not be located radially outside the compressor impeller 70. Nevertheless, it is preferred that at least a portion of the cooling chamber 20A is located radially outside the compressor impeller 70, thereby cooling a portion of the sealing plate 40 located radially outside the compressor impeller 70.

[0085] Moreover, the cooling chamber 20A does not necessarily have a substantially annular shape, but the cooling chamber 20A may have, for example, an arc shape. Nevertheless, it is preferred that the cooling chamber 20A has a substantially annular shape in order to effectively cool the through shaft 120 and the like positioned around the rotation axis 90A.

[0086] To provide the cooling chamber 20A, the shapes of the sealing plate 40 and the bearing housing 50 may be changed as needed. Therefore, as long as the cooling chamber 20A can be defined between the sealing plate 40 and the bearing housing 50, the recessed portion 42 of the sealing plate 40 and the recessed portion 53 of the bearing housing 50 may be omitted.

[0087] Next, other modified examples will be described. In the illustrated embodiment, the shape of the fixing member 160 may be changed. For example, the radially inner upright portion 163 of the fixing member 160 may be omitted. Also, for example, the radially outer upright portion 164 of the fixing member 160 may be omitted. Also with this arrangement, the coolant introduced into the cooling chamber 20A from the introduction hole 56 flows substantially toward the discharge hole 57; therefore, if a relatively large amount of coolant flows through the cooling chamber 20A, it is possible to cool the through shaft 120 and the like by heat exchange with the coolant.

[0088] In the illustrated embodiment, the fixing member 160 may be omitted. For example, if the spring member 150 is directly mounted on the through-shaft 120, the fixing member 160 may be omitted. In the illustrated embodiment, the shape of the sealing plate 40 may be changed. For example, the fixing protrusion 46 may be omitted. Also, for example, the partition 47 may be omitted. When the partition 47 is omitted, it is preferred to provide a partition protruding from the bottom of the recessed portion 53 of the bearing housing 50 for regulating the flow of the coolant.

Claims

1. A turbocharger, characterized in that include: a turbine impeller configured to be rotated by the flow of exhaust gas; a turbine housing housing the turbine wheel; a bearing housing secured to the turbine housing; a compressor housing secured to the bearing housing; a sealing plate, the sealing plate being located between the bearing housing and the compressor housing; a variable nozzle mechanism located within the turbine housing and configured to adjust an amount of exhaust gas flowing toward the turbine wheel; a plurality of through-shafts, each of the plurality of through-shafts extending through the bearing housing and connected to the variable nozzle mechanism, and the plurality of through-shafts being arranged on a circumference around a rotation axis of the turbine impeller; as well as a single spring member having a generally annular shape about the rotational axis and configured to urge all of the through-shafts toward the compressor housing, wherein the bearing housing and the sealing plate are configured to define a cooling chamber, wherein a coolant flows through the cooling chamber, Wherein, the spring component is located in the cooling chamber.

2. The turbocharger according to claim 1, characterized in that: The spring member includes a helical wave spring.

3. The turbocharger according to claim 2, characterized in that: All of the through-shafts are positioned to be equiangularly spaced in a circumferential direction around the rotation axis.

4. The turbocharger according to any one of claims 1 to 3, characterized in that: The bearing housing includes a through hole through which the through shaft is inserted; and A sealing member is located between an outer peripheral surface of the through-shaft and an inner peripheral wall of the through-hole, and the sealing member seals a gap between the through-shaft and the through-hole.

5. The turbocharger according to claim 4, characterized in that: The bearing housing is configured to define a retaining space that retains the sealing member; and The holding space is in communication with the cooling chamber.

6. The turbocharger according to claim 5, characterized in that: The cooling chamber has a generally annular shape.

7. The turbocharger according to claim 5, characterized in that: A retaining plate that retains the sealing member is mounted on the bearing housing; and The sealing member is sandwiched between an inner wall of the holding space and an end surface of the holding plate.

8. The turbocharger according to any one of claims 1 to 3, characterized in that: The compressor housing houses a compressor wheel connected to the turbine wheel; and At least a portion of the cooling chamber is located outside the compressor impeller in a radial direction perpendicular to the rotation axis of the turbine impeller.

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