JP2009036314A - Automatic change gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic change gear capable of securing durability of an oil seal even when a temperature of a housing is increased. <P>SOLUTION: This automatic change gear comprises an oil seal having an oil pump driven by a sprocket, arranged between a housing and a torque converter sleeve, and hydraulic-sealing a cover member, the sprocket, and a dry chamber for housing a space which is formed inside the housing in a radial direction and to which a predetermined hydraulic pressure is introduced. An oil groove communicating the space with a wet chamber is provided to at least one of a face opposed to the sprocket of the housing and a face opposed to the sprocket of the cover member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automatic transmission that includes an oil pump that is radially spaced from an input shaft.

  As a technique for driving an oil pump, a technique described in Patent Document 1 is disclosed. In this publication, a drive sprocket provided on the outer periphery of the torque converter sleeve and a driven sprocket provided on the oil pump are connected by a chain, and the oil pump is driven by the driving force of the engine.

  In the technique described in Patent Document 1, the drive sprocket 34 is rotatably supported between the side surface of the housing 41 and the side surface of the cover 42. A thrust washer 42 a is interposed between the housing 41 and the drive sprocket 34, and a shim 41 a is interposed between the cover 42 and the drive sprocket 34. An oil seal is attached between the torque converter sleeve and the housing 41 to seal the housing 41 and the space in which the torque converter 2 is accommodated in a liquid-tight manner. The region sealed by the oil seal communicates with an oil passage that supplies converter pressure into the torque converter.

In the above prior art, generally, clearances are set on both sides of the thrust washer 42a and the shim 41a. Thereby, when an excessive hydraulic pressure is supplied into the torque converter chamber, an excessive increase in hydraulic pressure in the torque converter chamber is suppressed by leaking oil from the clearance.
JP 2005-325979 A

  However, if the housing or cover is thermally expanded due to oil temperature rise, etc., the above clearance cannot be secured, and proper leakage cannot be secured when excessive converter pressure is supplied, and the durability of the oil seal There was a problem of getting worse.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide an automatic transmission capable of ensuring the durability of an oil seal even when the temperature of a housing rises. .

  In order to achieve the above object, according to the present invention, a housing that defines a wet chamber in which an external oil pump is accommodated and a dry chamber in which a torque converter is accommodated, the wet chamber, and a transmission mechanism accommodation chamber. And a cover member that is provided in the wet chamber, and is positioned and supported at one end in the axial direction by the housing and at the other end by the cover member, and transmits drive to the oil pump using a chain. A sprocket that is connected to the sprocket so that power can be transmitted to the sprocket at a portion extending axially outward from the housing from the torque converter, and disposed between the housing and the torque converter sleeve. The cover member, the sprocket, and the housing are formed on the radially inner side to guide a predetermined hydraulic pressure. And an oil seal that tightly seals the dry chamber with the space between the surface of the housing facing the sprocket and the surface of the cover member facing the sprocket. And an oil groove that communicates with the wet chamber.

  Therefore, even if the housing and the cover member are thermally expanded, the oil groove can surely communicate the space and the wet chamber, preventing the oil seal from being pushed out and preventing oil from flowing out. However, the durability of the oil seal can be improved.

  Hereinafter, the best mode for realizing the automatic transmission of the present invention will be described based on the embodiments shown in the table.

  FIG. 1 is a partial sectional view showing the vicinity of a torque converter of an automatic transmission equipped with an external oil pump. The transmission unit housing 40 attached to the engine 1 accommodates the torque converter 2 and forms a dry chamber DR with the engine 1, the input shaft 5, the torque converter 2, etc. A cover 42 and a stator shaft 43 to be supported, and an oil pump housing 44 for housing the oil pump 3 are provided. The cover 42 according to the first embodiment is formed of a material such as aluminum to reduce the weight, and the stator shaft 43 is formed of an iron-based material to ensure strength as a support. The oil pump 3 according to the present embodiment is disposed away from the input shaft 5 in the radial direction.

  An engine drive plate 12 is connected to the crankshaft 11 that outputs the driving force of the engine 1 by bolts. A connecting portion 12 a is provided on the radially outer side of the engine drive plate 12 and is connected to the converter cover 21 of the torque converter 2. A pilot boss 21 a is provided in the engine 1 side shaft center portion of the converter cover 21, and the torque converter 2 is centered and supported by a bearing hole 11 a provided in the shaft center of the crankshaft 11. An impeller shell 22 is connected to the side of the converter cover 21 facing the engine 1 by welding, and a torque converter sleeve 23 is connected to the inner diameter side of the impeller shell 22 by welding. The outer periphery of the torque converter sleeve 23 and the axially outer side of the torque converter housing 41 is configured as a wet chamber WR, and the first sprocket 34 is fitted to the tip of the torque converter sleeve 23 in the wet chamber WR.

  A pump impeller 24 is provided on the inner peripheral side of the impeller shell 22, and a turbine runner 25 is disposed on the axial engine 1 side via a stator 26. A one-way clutch OWC fixed to the stator shaft 43 is provided on the inner periphery of the stator 26.

  When the engine 1 is driven, the crankshaft 11, the engine drive plate 12, the converter cover 21, the impeller shell 22, and the torque converter sleeve 23 rotate together. This rotation is transmitted to the input shaft 5 by the oil in the torque converter 2 via the stator 26 and the turbine runner 25. Further, the first sprocket 34 fitted to the torque converter sleeve 23 transmits the driving force of the engine 1 to the second sprocket 32 provided on the oil pump driving shaft 31 via the chain 33 to drive the oil pump 3. . Although the transmission mechanism is omitted in the first embodiment, a belt-type continuously variable transmission is mounted in the first embodiment. In addition, not only a belt-type continuously variable transmission but a stepped automatic transmission may be set as appropriate, and there is no particular limitation.

  FIG. 2 is an enlarged sectional view of the torque converter sleeve 23 and the first sprocket 34 portion. A first bush 60 is provided between the inner periphery of the axially extending portion 23a of the torque converter sleeve 23 and the outer periphery of the stator shaft 43, and supports the torque converter sleeve 23 in a rotatable manner. A second bush 70 is provided between the first sprocket 34 and the stator shaft 43, and supports the first sprocket 34 so as to be rotatable.

  A shim 41 a is provided between the first sprocket 34 and the torque converter housing 41, and a thrust washer 42 a is provided between the first sprocket 34 and the cover 42, whereby the axial direction of the first sprocket 34 Has achieved positioning. An oil groove 410 is formed between the torque converter housing 41 and the shim 41a. The position and action of the oil groove 410 in the circumferential direction will be described later. An oil seal 50 is provided between the torque converter housing 41 and the axially extending portion 23a to seal the dry chamber DR and the wet chamber WR in a liquid-tight manner.

  An oil passage A is formed between the stator shaft 43 and the input shaft 5. In the radial direction of the stator shaft 43, an oil hole 43a formed in the radial direction communicating with the oil passage A is formed. The converter pressure supplied from the oil passage A is supplied into the torque converter 2 through the oil hole 43a and between the stator shaft 43 and the torque converter sleeve 23 (see the thick arrow in FIG. 2). At this time, as indicated by an arrow branched from the arrow of FIG. 2 to the first sprocket 34 side, the converter pressure is transferred between the thrust washer 42a, the first sprocket 34 and the stator shaft 43 and the axially extending portion 23a. And from the oil groove 410 to the wet chamber WR. In other words, a space is formed on the radially inner side of the cover member 42, the first sprocket 34, and the torque converter housing 41 to guide a predetermined hydraulic pressure, and this space communicates with the wet chamber WR via the oil groove 410. ing.

  Here, the background of setting the oil groove 410 will be described. In the configuration in which no oil groove is provided as in the technique described in Patent Document 1, the clearance between the shim 41a and the first sprocket 34, or between the torque converter housing 41 and the shim 41a, and the thrust It is designed to leak from the clearance between the washer 42 a and the cover 42 and between the thrust washer 42 a and the side surface of the first sprocket 34.

  However, it has been found that when the torque converter housing 41 and the cover 42 are thermally expanded due to an increase in the oil temperature, the designed clearance cannot be secured and the assumed leak may not be performed. At this time, if an excessive converter pressure is supplied to a space to which a predetermined hydraulic pressure is guided, an excessive pressure may act on the oil seal 50 and be pushed out to the dry chamber DR side.

  In order to solve the above-mentioned problem, it is also conceivable to form an oblique oil passage or the like in the torque converter housing 41 that communicates the inner peripheral side and the outer peripheral side of the shim 41a and the thrust washer 42a. However, drilling increases the number of processing steps and is not preferable from the viewpoint of cost. Therefore, in the first embodiment, the oil groove 410 that can be integrally formed when the torque converter housing 41 is cast is provided. Therefore, it is not necessary to make an oil groove by shaving or drilling, and it can be formed easily and inexpensively during material molding.

  Here, when the oil groove 410 is formed, if the oil groove 410 is simply formed in the radial direction, the oil leaked from the oil groove 410 is applied to the chain 33, and stirring is performed by scattering the oil. It has been found that there is a new problem that the pump discharge capacity is reduced due to the generation of resistance and the generation of bubbles by stirring. Therefore, in the first embodiment, the oil leaked from the oil groove 410 is formed at a position where it does not reach the chain 33. Hereinafter, it demonstrates using drawing.

  FIG. 3 is a schematic front view of the automatic transmission on which the belt type continuously variable transmission according to the first embodiment is mounted as viewed from the engine 1 side. The belt type continuously variable transmission includes a primary pulley PP to which the driving force output from the torque converter 2 is input, a belt VB that transmits the driving force of the primary pulley PP, and a driving force that is input via the belt VB. 2 and a secondary pulley SP that transmits to the drive wheel via an idler gear IG and a differential DEF, and is arranged with the positional relationship shown in FIG.

  A first sprocket 34 is disposed on the same axis as the primary pulley PP. The oil pump 3 is disposed on the diagonally lower right side in FIG. 3 from the first sprocket 34. A second sprocket 32 is provided on the same axis as the oil pump 3 and is connected via a chain 33.

  As shown in FIG. 3, the oil groove 410 according to the first embodiment is a position that is substantially horizontal when the vehicle is mounted, and is formed in the radial direction toward the outer side of the rotation track of the chain 33. Thereby, the tip of the oil groove 410 can be set at a position farthest from the chain 33, and even if oil leaks from the oil groove 410, the oil can hardly be applied to the chain 33.

  As shown by the auxiliary line drawn in the vertical direction from the horizontal plane in FIG. 3, the position that is substantially horizontal when mounted on the vehicle is the position that is most unlikely to be applied to the chain 33, but is above the position that is substantially horizontal. If the tip of the oil groove is open in a region on the side where the oil pump 3 does not exist with respect to the auxiliary line, the chain 33 will not be oiled. Further, if the tip of the oil groove is open outside the rotational track of the chain 33 below the position that is substantially horizontal, the chain 33 will not be oiled. Therefore, when there is a degree of design freedom in the position of the opening of the oil groove tip, the oil groove tip may be set to open in the shaded area in FIG.

The effects based on the configuration of the first embodiment will be listed below.
1) A torque converter housing 41 that defines a wet chamber WR in which an external oil pump 3 is accommodated and a dry chamber DR in which the torque converter 2 is accommodated, a wet chamber WR, and a transmission mechanism accommodation chamber. The cover member 42 is defined, and is provided in the wet chamber WR. One end in the axial direction is positioned and supported by the torque converter housing 41 and the other end is supported by the cover member 42, and the oil pump 3 is driven by the chain 33. , A torque converter sleeve 23 connected to the first sprocket 34 in a portion extending from the torque converter 2 to the wet chamber side in the axial direction than the torque converter housing 41, and a torque converter The cover member 42 and the first sprocket are disposed between the housing 41 and the torque converter sleeve 23. And an oil seal 50 that is formed on the radially inner side of the torque converter housing 41 to guide a predetermined hydraulic pressure and oil-tightly seals the dry chamber DR. An oil groove 410 is provided on the surface facing the first sprocket 34 to communicate a space where a predetermined hydraulic pressure is guided to the wet chamber WR.

  Therefore, even if the torque converter housing 41 and the cover member 42 are thermally expanded, the oil groove 410 can reliably communicate the space with the wet chamber WR, and the oil seal 50 is prevented from being pushed out. The durability of the oil seal 50 can be improved while preventing the oil from flowing out.

  2) The oil groove 410 is a position that is substantially horizontal when the vehicle is mounted, and is formed in the radial direction toward the outer side of the rotation track of the chain 33.

  Therefore, the tip of the oil groove 410 can be set at a position farthest from the chain 33, and even if oil leaks from the oil groove 410, it is possible to make the chain 33 difficult to get oil, and stirring by scattering the oil. It is possible to avoid a decrease in pump discharge capacity due to generation of resistance and generation of bubbles due to stirring.

  3) The oil groove 410 is formed integrally with the torque converter housing 41 by casting. Therefore, it can be produced easily and inexpensively without increasing the number of processing steps.

  Although the first embodiment has been described above, other configurations are also included in the scope of the claims. Specifically, in the first embodiment, the oil groove 410 is provided in the torque converter housing 41. However, similar effects can be obtained even if the oil groove is formed on the cover member 42 side. At this time, the cover member 42 may be integrally molded by casting.

FIG. 3 is a partial cross-sectional view showing the vicinity of a torque converter of an automatic transmission provided with an external oil pump in Embodiment 1. It is an expanded sectional view of the torque converter sleeve and the 1st sprocket part in Example 1. It is the schematic front view which looked at the automatic transmission in Example 1 from the axial direction engine side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Oil pump 5 Input shaft 11 Crankshaft 12 Engine drive plate 21 Converter cover 22 Impeller shell 23 Torcon sleeve 24 Pump impeller 25 Turbine runner 26 Stator 31 Oil pump drive shaft 32 Second sprocket 33 Chain 34 First sprocket 40 Unit housing 41 Torque converter housing 42 Cover 43 Stator shaft 44 Oil pump housing 50 Oil seal 410 Oil groove
WR wet room
DR Drying room

Claims (3)

A housing defining a wet chamber in which an external oil pump is accommodated and a dry chamber in which a torque converter is accommodated;
A cover member defining the wet chamber and the transmission mechanism housing chamber;
A sprocket that is provided in the wet chamber, is positioned and supported by the housing with one end in the axial direction and the other end with the cover member, and transmits a drive to the oil pump using a chain;
A torque converter sleeve connected to the sprocket so that power can be transmitted in a portion extending from the torque converter to the wet chamber side in the axial direction from the housing;
An oil seal that is disposed between the housing and the torque converter sleeve and that is oil tight between the cover member, the sprocket, and a space that is formed on the radially inner side of the housing to guide a predetermined hydraulic pressure. When,
In an automatic transmission with
An automatic transmission comprising an oil groove that communicates the space and the wet chamber on at least one of a surface of the housing facing the sprocket and a surface of the cover member facing the sprocket. The automatic transmission according to claim 1, wherein
2. The automatic transmission according to claim 1, wherein the oil groove is formed at a position that is substantially horizontal when the vehicle is mounted, and is formed in a radial direction toward an outer side of the rotation track of the chain. The automatic transmission according to claim 1 or 2,
The automatic transmission is characterized in that the oil groove is formed integrally with the housing and / or the cover member by casting.

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