JP2001027310A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure concentricity between a spigot engagement portion of an extension housing and a bearing engagement face without employing two side machining. SOLUTION: This automatic transmission is centered by spigotwise engagement of a transmission case 1 with an extension housing 2 to allow a bearing 3 provided within the extension housing 2 attached to the rear end of the transmission case 1 to support an output shaft 4 of the transmission. The read for two side machining is eliminated by conforming the inside diameter of a bearing engagement hole 22 of the extension housing 2 to the outside diameter of an engagement part 11 of the transmission case 1 and having the bearing engagement hole 22 also serve as a spigot engagement portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission, and more particularly, to a structure for connecting an extension housing to a transmission case accommodating the transmission mechanism.

[0002]

2. Description of the Related Art In an automatic transmission for transmitting the power of an engine vertically mounted on a vehicle to wheels, an engine and an automatic transmission directly connected to the engine are supported on a vehicle body in cooperation with mounting of the engine. The automatic transmission has an extension housing at the rear of the transmission case. The extension housing serves to support the output shaft of the transmission in addition to the role of the support. For this reason, the extension housing is required to have high concentricity with respect to the axis of the transmission case. For this reason, the extension housing and the transmission case are connected to each other by means of a male fitting for centering. As a conventional example adopting such a connection structure, there is a technique disclosed in Japanese Patent Application Laid-Open No. S61-153061. In this conventional technique, centering is performed by fitting an inner peripheral surface of an outer peripheral wall of an extension housing to an outer periphery of an annular flange portion protruding from a rear wall of a transmission case.

[0003]

When the centering structure as described above is employed, the extension housing side is provided to secure concentricity between the shaft support bearing provided in the extension housing and the fitting portion for the stirrer. In the inner peripheral surface of the housing in which the bearing is fitted,
It is necessary to perform advanced processing on both surfaces to achieve concentricity of the inner peripheral surface of the heat fitting portion, and such processing is not always easy, and leads to an increase in cost due to an increase in the number of processing steps.

The present invention has been made in view of the above circumstances, and an automatic transmission having a concentricity between a ring fitting portion and a bearing fitting surface can be ensured without using two-side processing. It is intended to be provided on the machine.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an extension housing mounted on a rear end of a transmission case and supporting an output shaft of the transmission by a bearing disposed in the extension housing. Automatic transmission, wherein the transmission case and the extension housing are centered by fitting, the inner diameter of the bearing fitting hole of the extension housing is matched with the outer diameter of the fitting portion of the transmission case. It is characterized by the following.

In the above configuration, the output shaft is supported through a sleeve in a shaft insertion hole in a rear wall of a transmission case, and an oil passage is provided between the shaft insertion hole and the sleeve in a bearing fitting hole. It is effective to adopt a configuration in which a groove is formed.

Further, it is effective that a drain groove is formed in the outer peripheral surface of the fitting portion so as to communicate between the inside of the bearing fitting hole and the inside of the extension housing.

Alternatively, a drain groove may be formed on the inner peripheral surface of the bearing fitting hole to allow communication between the inside of the bearing fitting hole and the inside of the extension housing.

Specifically, it is effective that the drain groove is provided at a circumferential position above the lowermost position of the outer peripheral surface of the fitting portion by a predetermined amount.

[0010]

According to the structure of the first aspect,
By matching the inside diameter of the bearing fitting hole of the extension housing with the outside diameter of the fitting part of the transmission case, the bearing fitting hole can also serve as the oil fitting part between the transmission case and the extension housing. Therefore, it is possible to reduce the number of machining parts requiring accuracy by one, improve the alignment accuracy between the transmission case and the extension housing, and reduce the cost of machining and managing the extension housing.

According to the second aspect of the present invention, the lubricating oil passage from the transmission case to the bearing in the extension housing does not pass through the output shaft extending between the transmission case and the extension housing, and does not pass through the outer periphery of the sleeve. It can be configured very simply by using. In addition, since a shaft oil passage is not used for supplying lubricating oil, a common oil passage for servo pressure is provided in the shaft to supply servo pressure from the rear of the transmission case into the transmission and to provide bearings in the extension housing. And supply of lubricating oil to the oil supply can be performed in parallel with a simple oil passage configuration.

According to the third aspect of the present invention, since the drain groove is formed on the outer peripheral surface of the fitting portion, the drainage of the lubricating oil from the bearing can be performed by a simple process such as cutting out a part of the transmission case. The oil passage can be secured without providing an oil hole in the case, which is complicated to process.

According to the fourth aspect of the present invention, since the drain groove is formed in the inner peripheral surface of the bearing fitting hole, the drainage of the lubricating oil from the bearing can be performed by a simple process such as cutting out a part of the extension housing. The oil passage can be secured without providing an oil hole in the case, which is complicated to process.

Further, in the structure of the fifth aspect, by appropriately setting the formation position of the drain groove, the oil level in the bearing fitting hole can be appropriately maintained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an axial section of a rear portion of a front engine rear drive (FR) type automatic transmission according to a first embodiment to which the present invention is applied, and FIG. 2 shows an end surface of the rear portion (only a shaft portion has a transverse section). ). This automatic transmission has a configuration in which an extension housing 2 is attached to a rear end of a transmission case 1 and an output shaft 4 of the transmission is supported by bearings 3 disposed in the extension housing 2. According to a feature of the present invention, the inner diameter of the bearing fitting hole 22 of the extension housing 2 is matched with the outer diameter of the fitting portion 11 of the transmission case 1 so that the extension housing 1 and the extension housing 2 are centered by fitting. I have.

Hereinafter, each part will be described. The transmission case 1 has a shaft insertion hole 13 penetrating the rear wall 10,
A fitting portion 11 is formed to surround the shaft insertion hole 13 and extend rearward in the axial direction from the rear wall 10, and further has a fitting portion 12 extending in the axial direction from the outer peripheral wall of the case. A valve body 6 is attached to a flat portion on the lower side of the case, and the outside thereof is closed by an oil pan 7. FIG. 1 shows a cross-sectional shape ignoring the position in the axial direction, and FIG. 2 shows an actual positional relationship in the axial direction. As shown in FIG. A lubricating oil supply passage 16 is formed to extend from the valve body 6 to the shaft insertion hole 1.
A supply oil passage 17 for the servo pressure reaching the inner periphery of No. 3 is formed. Lubricating oil supply passage 16 and servo pressure supply oil passage 17
Are opened in the inner peripheral surface of the shaft insertion hole 13 at different circumferential positions, specifically, at positions slightly shifted left and right from the lowermost position of the inner periphery of the shaft insertion hole 13. An oil groove 14 extending in the axial direction is formed in the inner periphery of the shaft insertion hole 13 at a position matching the opening of the inner peripheral surface of the shaft insertion hole 13 of the supply oil passage 16.

The output shaft 4 has its outer periphery rotatably supported by the inner periphery of the shaft insertion hole 13 via the sleeve 5. The output shaft 4 has an in-shaft oil passage 46 extending forward in the axial direction, and a rear end thereof is connected to a circumferential groove 44 formed on the outer periphery of the shaft via a radial oil passage 45. And sleeve 5
An opening 51 is formed at a position matching the opening of the inner peripheral surface of the shaft insertion hole 13 of the supply oil passage 17. The rear end of the output shaft 4 is reduced in diameter in three stages with respect to the support part by the sleeve 5, and the radial ball bearing 3 is fixed to the outer periphery of the first reduced diameter part by fitting its inner race. ,
A spline for preventing the joint member 41 from rotating is fixed behind the fitting portion. The outer circumference of the second reduced diameter portion is
It is a contact surface of a seal ring 43 which is fitted to the inner periphery of the joint member 41 to prevent the spline fitting portion from leaking. A male screw for screwing the lock nut 42 is formed on the outer periphery of the third reduced diameter portion. The member 9 fitted on the outer periphery of the joint member 41 indicates a dust cover.

The extension housing 2 has a mating portion with the transmission case 1 extending axially forward from the outer periphery of the end wall 20 and a boss portion 21 also extending from the end wall 20 axially forward on the inside. The shaft insertion hole passing through the inside of the boss portion 21 is a stepped hole. The large diameter side of the step hole is
The bearing fitting hole 22 is formed, and the ball bearing 3
However, the outer race is fitted to the inner peripheral surface of the bearing fitting hole 22 by interference fitting, and the smaller diameter side of the stepped hole is the output shaft 4.
The oil seal 8 is a fitting hole for sealing between the outer periphery of the joint member 41 spline-fitted to the first reduced diameter portion and the shaft insertion hole. Further, a mount portion 24 is formed to protrude rearward and downward from the end wall 20.

According to the structure of direct fitting between the fitting portion 11 of the transmission case 1 and the boss portion 21 surrounding the bearing fitting hole 22 as described above, the extension housing 2 is connected to the transmission. At the time of attachment to the rear end of the case 1, the outer end of the bearing fitting hole 22 of the extension housing 2 is fitted to the outer peripheral surface of the fitting portion 11 of the transmission case 1, whereby the two are positioned relative to each other. You. In this case, the fitting portion 11 of the transmission case 1
Is processed to ensure concentricity with the shaft insertion hole 13, and the bearing fitting hole 22 of the extension housing 2 is processed so as to ensure concentricity with the bearing 3. The fitting surfaces of the two can be made concentric with the axis of the output shaft 4 within the range of the processing error.

When this structure is compared with the conventional structure, when the conventional bearing housing hole on the extension housing side and the fitting hole for the transmission case are holes having a diameter difference, the bearing fitting hole is fitted with the bearing fitting hole. While a processing error occurs between the hole and the hole, the configuration of the present invention provides an advantage that the processing error can be eliminated.

When the bearing fitting hole 22 is directly fitted to the outer peripheral surface of the fitting portion 11 as described above, the oil escape path after lubricating the bearing 3 is located at the front end side of the transmission case 1 side. In the present embodiment, the outer peripheral surface of the fitting portion 11 is closed with the inside of the bearing fitting hole 22 because the fitting portion 11 is closed and the rear side is closed with a step portion with the reduced diameter hole for oil seal fitting. A drain groove 15 for communicating the transmission case 1 with the inside of the mating portion of the extension housing 2
Are formed. The drain groove 15 is
A predetermined amount above the lowermost position of the outer peripheral surface (see FIG. 2)
Are provided as cutouts at the corners of the fitting portion 11 at circumferential positions.

With the formation of each oil groove, the oil supplied from the valve body 6 passes through the oil passage 16 and passes through the oil groove 1.
4, one is supplied to the front side of the transmission through the circumference of the shaft, and the other is supplied into the bearing fitting hole 22. Then, the oil that has lubricated and cooled the bearing 3 is discharged from the drain groove 15 into a mating portion surrounded by the rear wall 10 of the transmission case 1 and the end wall 20 of the extension housing 2 and flows to the bottom, and a return oil passage (not shown) And returns to the oil pan 7. Since the return oil passage is secured by the formation of the drain groove 15, the bearing fitting hole 2 is formed.
In 2, oil accumulates only below the position where the drain groove 15 is formed, and a constant oil level is maintained.

On the other hand, similarly, a hydraulic pressure for engaging a clutch or a brake (not shown) is output from the valve body 6 to the supply oil passage 17 as a servo pressure for operating the hydraulic servo, if necessary. The fluid enters the circumferential groove 44 around the output shaft shaft from the opening 51 of the sleeve 5, and is supplied to a hydraulic servo cylinder (not shown) through the radial oil passage 45 and the in-shaft oil passage 46.

Thus, according to the oil passage configuration of the above-described embodiment, the supply oil passage for the lubricating oil and the oil supply passage for the servo pressure are separated by using the sleeve 5, so that the same as the rear wall of the transmission case 1 is formed. Despite arranging the oil passages in the case side by side in the axial direction, it is possible to supply both the lubrication pressure and the servo pressure with an extremely simple configuration without forming two oil passages in the shaft. ing.

Next, FIGS. 3 and 4 show a second embodiment in which the drain groove configuration is changed from the first embodiment.
In this embodiment, a drain groove 23 that connects the inside of the bearing fitting hole 22 and the inside of the extension housing 2 is formed on the inner peripheral surface of the bearing fitting hole 22 on the extension housing 2 side. Drain groove 23 in this case
Is the bearing fitting hole 2 of the extension housing.
The front end of the inner periphery of the boss 21 surrounding the 2 is cut off in the axial direction by a predetermined width to form a groove having an open front end. The position of the drain groove 23 is provided at a circumferential position above the lowermost position of the outer peripheral surface of the fitting portion 11 by a predetermined amount (see FIG. 4), as in the case of the first embodiment.

Even with such a drain groove configuration, the oil supplied into the bearing fitting hole 22 is supplied to the drain groove 23
It accumulates only below and maintains a constant oil level. Excess oil that has lubricated and cooled the bearings 3 is similarly discharged from the drain groove 23 into a mating portion surrounded by the rear wall 10 of the transmission case 1 and the end wall 20 of the extension housing 2.

FIGS. 5 and 6 show a third embodiment in which the configuration of the drain groove is further changed from the first embodiment. In this embodiment, similarly to the second embodiment, the bearing fitting hole 2 is provided at a similar circumferential position on the inner peripheral surface of the bearing fitting hole 22 on the extension housing 2 side (see FIG. 6).
A drain groove 23 ′ for communicating the inside of the extension housing 2 with the inside of the extension housing 2 is formed. The drain groove 23 ′ in this case is formed by notching the front end of the boss 21 in a predetermined width in the radial direction so that the outer peripheral side is formed. It is an open groove. The advantage of forming the drain grooves 23, 23 'on the extension housing side as in the second and third embodiments is that processing is performed on a smaller and lighter component than the transmission case, so The point is that the workability is improved.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the illustrated embodiments, and various modifications may be made without departing from the scope of the claims. The specific configuration can be changed and implemented.

[Brief description of the drawings]

FIG. 1 is an axial cross-sectional view showing a rear shape of an automatic transmission according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the automatic transmission according to the first embodiment as viewed from a rear end face side of a transmission case.

FIG. 3 is a partial axial sectional view showing a second embodiment in which a drain groove configuration is changed.

FIG. 4 is a partial cross-sectional view showing a drain groove configuration according to a second embodiment.

FIG. 5 is a partial axial sectional view showing a third embodiment in which a drain groove configuration is changed.

FIG. 6 is a partial cross-sectional view showing a drain groove configuration according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission case 2 Extension housing 3 Ball bearing 4 Output shaft 5 Sleeve 10 Rear wall 11 Fitting part 13 Shaft insertion hole 14 Oil groove 15 Drain groove 22 Bearing fitting hole 23, 23 'Drain groove

Continued on the front page (72) Inventor Satoru Kasuya 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Inventor Masaaki Nishida 10 Takane, Fujii-cho, Anjo, Aichi Aisin Ai (72) Inventor Masahiro Hayabuchi 10 Takane, Fujii-machi, Anjo, Aichi Prefecture F-term (reference) 3J063 AA01 AC04 BB48 CA09 CB58 CD09 CD42 CD45 XA37 XD47 XE22

Claims (5)

[Claims] 1. An automatic transmission in which an extension housing is attached to a rear end of a transmission case and an output shaft of the transmission is supported by bearings disposed in the extension housing, wherein the transmission case and the extension housing are connected to each other. An automatic transmission wherein the inner diameter of a bearing fitting hole of an extension housing is matched with the outer diameter of a fitting portion of a transmission case in the centering by fitting. 2. The output shaft is supported in a shaft insertion hole in a rear wall of a transmission case via a sleeve, and an oil groove communicating with a bearing fitting hole is formed between the shaft insertion hole and the sleeve. The automatic transmission according to claim 1, wherein the automatic transmission is provided. 3. The automatic transmission according to claim 1, wherein a drain groove communicating between the inside of the bearing fitting hole and the inside of the extension housing is formed on an outer peripheral surface of the fitting portion. 4. The automatic transmission according to claim 1, wherein a drain groove communicating between the inside of the bearing fitting hole and the inside of the extension housing is formed on an inner peripheral surface of the bearing fitting hole. 5. The automatic transmission according to claim 3, wherein the drain groove is provided at a circumferential position above the lowermost position of the outer peripheral surface of the fitting portion by a predetermined amount.