Torque converter with bushing for aligning a bearing between turbine and stator

Abstract

Torque converter (10) which includes: a stator (66); a turbine (20); a bushing (34) provided on an inner circumferential surface of the turbine (20); and a thrust bearing (86) which is provided axially between the turbine (20) and the stator (66), wherein the bushing (34) bears against an inner circumferential surface (86d) of the thrust bearing (86) to guide the turbine bearing, wherein the bushing (34) includes an axially extending inner section (92) with an outer circumferential surface which abuts the inner circumferential surface of the turbine (20), wherein the axially extending inner section (92) has an inner circumferential surface which is provided to abut an outer circumferential surface (35a) of a stator shaft (35).

Description

[0001] The present disclosure relates generally to torque converters and in particular to an alignment of a bearing between a turbine and a stator in a torque converter. BACKGROUND OF THE INVENTION

[0002] US Patent 7,802,668 discloses a stator side plate containing tongues for centering a bearing. US Patent 8,453,439 also discloses an arrangement for centering a bearing on a stator side plate.

[0003] US patent 7,938,243 discloses a pressure plate between the cover plate and the flange. The pressure plate contains adjusting tongues.

[0004] Publications DE 198 61 502 A1 and DE 198 26 351 A1 disclose a hydrodynamic torque converter comprising a stator, a turbine, a bushing, and a thrust bearing located axially between the turbine and the stator, wherein the bushing rests against an inner circumferential surface of the thrust bearing to guide the turbine bearing. The object of the invention is to further improve known torque converters, particularly with regard to the thrust bearing and / or the bushing. BRIEF SUMMARY OF THE INVENTION

[0005] A torque converter is provided. The torque converter includes a stator, a turbine, a bushing provided on an inner circumferential surface of the turbine, and a thrust bearing provided axially between the turbine and the stator. The bushing rests against an inner circumferential surface of the thrust bearing to guide the turbine bearing.

[0006] A method for forming a torque converter is also provided. The method includes providing a bushing on an inner circumferential surface of a turbine; and providing a thrust bearing axially between the turbine and a stator such that the bushing rests against the inner circumferential surface of the thrust bearing to guide the turbine bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention is described below with reference to the following drawings, wherein: Fig. 1 a lateral cross-sectional view of a torque converter according to an embodiment of the present invention; and Fig. 2 an enlarged view of a section of the in Fig. Figure 1 shows the torque converter, illustrating the location of a pressure roller bearing between a turbine and a stator. DETAILED DESCRIPTION

[0008] The disclosure provides a cost-effective design for centering and retaining a rolling bearing, in particular for a rolling bearing axially located between a turbine casing and the stator of a torque converter. A bushing on an inner diameter of the turbine casing projects upwards to support and center the turbine casing and to guide the turbine bearing. The projecting step can be continuous or formed by structured features that are uniformly spaced around the circumference.

[0009] Fig. Figure 1 shows a partial side cross-sectional view of a torque converter 10 according to an embodiment of the present invention. The torque converter 10 is rotatable about a central axis 11 and comprises a front cover 12, which is connected to a crankshaft of an internal combustion engine, and a rear cover 14, which forms a housing 16 of an impeller or a pump 18. The terms axial, radial, and circumferential used herein refer to the central axis 11. The torque converter 10 also comprises a turbine 20 with a turbine housing 22 and an inner ring 24, which holds a plurality of turbine blades 26 between them. The blades 26 can be attached by tongues on a side of the turbine housing 22 facing the engine and by tongues on a side of the inner ring 24 facing the transmission.

[0010] The turbine housing 22 contains a rounded blade support section 28, shaped like an annular shell against which the edges of the turbine blades 26 facing the engine rest. Radially within the blade support section 28, the turbine housing 22 contains a radially inner annular extension 30, which is connected at a radially inner end to a retaining ring 32 of the turbine 20. This retaining ring is thicker than the turbine housing 22, and its inner circumferential surface defines a central bore of the turbine 20. The retaining ring 32 rests against an outer circumferential surface of a bushing 34, which serves to guide a stator shaft 35.

[0011] The impeller 18 contains impeller blades 36, which are attached by tongues to each side of the impeller housing 16 facing the gearbox and by tongues to each side of the inner ring 38 of the impeller facing the motor. The impeller housing 16 contains a rounded blade support section 40, which is shaped like an annular shell and against which the edges of the impeller blades 36 facing the gearbox bear. Radially within the blade support section 40, the impeller housing 16 contains an annular radially inner extension 42, which extends radially inward from the blade support section 40. A radially inner end of the extension 42 is connected to an impeller hub 44.

[0012] A damper assembly is arranged axially in a known manner between a radially extending region of the front cover 12 and the turbine 20 and serves to transmit torque from the turbine 20 to a drive shaft of the gearbox. The damper assembly includes a first cover plate 48, which faces the turbine and connects the damper assembly to the turbine 20. The turbine housing 22, the retaining ring 32, and the cover plate 48 are riveted together by rivets 50, which extend axially through the turbine housing 22, the retaining ring 32, and the cover plate 48 to enclose the radially inner extension 30 of the turbine housing 22 between the retaining ring 32 and the cover plate 48.The damper assembly can also include an additional cover plate for holding a plurality of circumferentially spaced springs, together with the cover plate 48, and a drive flange equipped with a hub for direct connection to a transmission drive shaft. The drive flange has circumferentially spaced slots that accommodate the springs, so that during operation of the torque converter 10, the cover plates transmit torque via the springs to the drive flange to drive the transmission drive shaft. The torque converter 10 also includes a lock-up clutch connected to the damper assembly to lock the front cover 12 to the turbine 20 via the damper assembly during operation of the torque converter 10.The lock-up clutch can contain a clutch disc and a piston that is axially displaceable to press the clutch disc against another surface and thus close the lock-up clutch.

[0013] The torque converter 10 also includes a stator 66 axially positioned between the turbine 20 and the impeller 18 to redirect the fluid flowing from the turbine blades 26 before it reaches the impeller 18, thereby increasing the efficiency of the torque converter 10. The stator 66 comprises a stator casting 68 containing a plurality of blades 70 and a stator body 72. The stator body 72 includes an outer section 72a, formed as an axially extending ring with the blades 70 mounted on its outer circumferential surface 72b, and an inner section 72c extending radially inward from the outer section 72a. The stator 66 also includes a freewheel clutch 74, which is aligned within the stator body 72 by a side plate 76.The side plate 76 extends radially along one side of the freewheel coupling 74 facing the turbine, the inner section 72c of the stator body 72 extends radially along the side of the freewheel coupling 74 facing the impeller, and the outer section 72a of the stator body 72 extends along an outer circumference of the freewheel coupling 74.

[0014] The freewheel clutch 74 comprises an inner race 78, an outer race 80, and a known rolling element / spring arrangement 82 radially between the inner race 78 and the outer race 80. An inner circumferential surface of the inner race 78 is designed such that it contains, for example, a tooth profile and is thereby rotationally fixed to an outer circumferential surface 35a of the stator shaft 35. The stator casting 68 is connected in a rotationally fixed manner to an outer circumferential surface of the outer running ring 80 via an inner circumferential surface of the outer section 72a and, depending on the operating conditions of the torque converter 10, the inner running ring 78 and the outer running ring 80 are connected to each other in a known manner by the rolling element / spring arrangement 82 in a rotationally fixed manner, so that the stator 66 rotates together with the stator shaft 35 or that the inner running ring 78 and the outer running ring 80 are rotatable relative to each other.An outer circumferential surface of the side plate 76 is held in an inner circumferential surface of the outer section 72a of the stator body 72.

[0015] An axial thrust bearing 84 facing the impeller is arranged axially between the stator 66 and the impeller 18. More precisely, the bearing 84 rests against a radially extending surface 72d of the inner section 72c of the stator body 72 and against a radially extending surface of the radially inner extension 42 of the impeller housing 16.

[0016] A thrust bearing 86 facing the turbine is arranged axially between the stator 66 and the turbine 20. The thrust bearing 86 contains rolling element elements 87, which, according to this embodiment, are needles, axially between a radially extending section 89a of a first running ring 89 facing the turbine and a radially extending section 91a of a second running ring 91 facing the stator. The first running ring 89 and the second running ring 91 also contain corresponding axially extending sleeves 89b, 91b for supporting a rolling element cage 93, which holds the rolling elements 87.

[0017] A first radially extending surface 86a of the rolling bearing 86, more precisely, of the radially extending section 91a of the second running ring 91, rests against a radially extending surface 76a of the side plate 76, and a second radially extending surface 86b of the rolling bearing 86, more precisely, of the radially extending section 89a of the first running ring 89, rests against a radially extending surface 20a of the turbine 20, which, according to this embodiment, is in particular a component of the retaining ring 32. According to another embodiment, the retaining ring 32 can be omitted, and the turbine housing 22 can extend radially further inwards to rest directly against the bushing 34, so that the radially extending surface 20a resting against the surface 86a is a component of the turbine housing 22.

[0018] Fig.Figure 2 shows an enlarged view of the arrangement of the pressure roller bearing 86 between the turbine 20 and the stator 66 according to an embodiment of the present invention. The side plate 76 includes an axially extending flange 76b facing the rear side, which projects into the freewheel clutch 74. The axially extending flange 76b facing the rear side forms an inner circumferential surface of the side plate 76 and extends along an outer circumferential surface of the inner race 78 to align the rolling element / spring arrangement 82.

[0019] The bushing 34 is annular and designed to bear against an inner circumferential surface 86d, more precisely, against the radially extending section 89b of the first race 89, in order to guide the thrust bearing 86. The bushing 34 comprises an axially extending inner section 92, a radially extending section 94 extending radially outward from the axially extending inner section 92, and an axially extending outer section 96 extending axially from an outer end of the radially extending section 94. The axially extending inner section 92 is provided at the central bore of the turbine 20, such that an outer circumferential surface 92a of the section 92, which is defined as the inner circumferential surface of the retaining ring 32, abuts the innermost circumferential surface 20a of the turbine 20, and an inner circumferential surface 92b of the section 92 abuts an outer circumferential surface 35a of the stator shaft 35.The radially extending section 94 extends radially along a section of the retaining ring 32 such that a radially extending surface 94a of section 94 abuts the radially extending surface 20a. The axially extending section 96 then extends axially away from surface 20a, with an outer circumferential surface 96a of section 96 abutting the inner circumferential surface 86d of the thrust bearing 86. Accordingly, the thrust bearing 86 is centered and retained by the bushing 34 to prevent radial movement.

[0020] According to this embodiment, the axially extending outer section 96 is formed from a plurality of axially extending tongues spaced apart from each other around the circumference; according to other embodiments, however, the axially extending outer section 96 can be formed as a continuous ring.

[0021] In the preceding description, the invention has been described with reference to certain exemplary embodiments and their examples. However, it is clear that various modifications and changes can be made to these without deviating from the broader essence and scope of protection of the invention, which is set out in the following claims. Accordingly, the description and drawings are to be regarded only as illustrations and not as limitations.

Claims

[1] Torque converter (10) comprising: a stator (66); a turbine (20); a bushing (34) provided on an inner circumferential surface of the turbine (20); and a thrust bearing (86) which is provided axially between the turbine (20) and the stator (66), wherein the bushing (34) bears against an inner circumferential surface (86d) of the thrust bearing (86) to guide the turbine bearing, wherein the bushing (34) includes an axially extending inner section (92) with an outer circumferential surface which abuts the inner circumferential surface of the turbine (20), wherein the axially extending inner section (92) has an inner circumferential surface which is provided to abut an outer circumferential surface (35a) of a stator shaft (35). [2] Torque converter (10) according to claim 1, wherein the bushing (34) further comprises an axially extending outer section (96) which abuts the inner circumferential surface (86d) of the thrust bearing (86) and a radially extending section (94) which extends from the axially extending inner section (92) to the axially extending outer section (96), wherein the radially extending section (94) abuts a radially extending surface (20a) of the turbine (20). [3] Torque converter (10) according to claim 1, wherein the thrust bearing (86) contains rolling elements (87) axially between the first and the second radially extending section (89a, 91a). [4] Torque converter (10) according to claim 1, wherein the stator (66) comprises a side plate (76) which rests against the thrust bearing (86), a stator casting (68) and a freewheel clutch (74), wherein the side plate (76) aligns the freewheel clutch (74) in the stator casting (68). [5] Method for forming a torque converter (10), the method comprising: Providing a bushing (34) on an inner circumferential surface of a turbine (20); and Providing a thrust bearing (86) axially between the turbine (20) and a stator (66) such that the bushing (34) rests against an inner circumferential surface (86d) of the thrust bearing (86) to guide the turbine bearing, wherein the bushing (34) includes an axially extending inner section (92) with an outer circumferential surface which abuts the inner circumferential surface of the turbine (20), wherein the axially extending inner section (92) has an inner circumferential surface which is provided to abut an outer circumferential surface of a stator shaft (35). [6] Method according to claim 5, wherein the bushing (34) further comprises an axially extending outer section (96) which abuts the inner circumferential surface (86d) of the thrust bearing (86) and a radially extending section (94) which extends from the axially extending inner section (92) to the axially extending outer section (96), wherein the radially extending section (94) abuts a radially extending surface (20a) of the turbine (20). [7] Method according to claim 6, wherein the stator (66) comprises a side plate (76) which abuts the thrust bearing (86), a stator casting (68) and a freewheel clutch (74), wherein the side plate (76) aligns the freewheel clutch (74) in the stator casting (68). [8] Method according to claim 5, wherein the thrust bearing (86) contains rolling elements (87) axially between the first and the second radially extending section (89a, 91a).

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