JP2003106409A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission surely improving sealability of hydraulic fluid sealed in a device case of a differential gear and sufficiently securing binding strength of a drive shaft and a side gear constructing differential gear device. SOLUTION: A cup side rubber layer 484b provided on an outer circumference surface of a cup part 483a of a cap member 482 is stuck on an inner circumference surface 477e of a tip of a head part of the side gear 477 while elastically deforming. A claw side rubber layer 484a provided on an outer side surface of a claw part 483b of the cap member is stuck on a groove side surface 477 of an annular groove 477h of the side gear. The cup part of the cap member is installed in such a manner that the same does not get into a hollow part of the side gear. Consequently, spline teeth 480 of drive shafts 453a, 453b are inserted into the hollow part deeply to adjacent of a tooth base of a gear part of the side gear to lengthen a engagement length of the drive shaft and the side gear splines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission in which a torque converter, a transmission unit and a differential device are housed in the same device case, and more particularly,
The present invention relates to an automatic transmission that prevents hydraulic oil sealed in a device case of a differential device from leaking to the outside.

[0002]

2. Description of the Related Art In an automatic transmission of this type, a differential device arranged on the output side is provided with a pinion for transmitting power from an engine through a torque converter and a transmission unit, and a substantially cylindrical gear meshed with the pinion. When the vehicle is assembled, the base end sides of the left and right drive shafts are fitted into the hollow parts of the left and right side gears that are arranged in the device case, and the front end side of the automatic transmission is It is in a state of being projected from the device case. With the left and right drive shafts attached, hydraulic oil is sealed in the device case.

Here, usually, a device case and a hollow part of the left and right side gears are partitioned on the base end side of the hollow parts of the left and right side gears (near the roots of the gear parts of the side gears), and they are operated in the device case. A cap member for sealing the oil is arranged to prevent the hydraulic oil from leaking from the differential device even if the left and right drive shafts are pulled out from the left and right side gears.

As a concrete structure of the cap member, for example, one described in JP-A-10-213209 is known. Explaining this conventional example with reference to FIG. 7 and FIG. 8, the side gear 300 is provided with a gear portion 301 that meshes with a pinion 298 on the base end side that is disposed inside the device case, and that is closer to the tip end side than the gear portion 301. Spline teeth 303 are provided on the inner peripheral surface of the hollow portion 302. Also, the hollow portion 302
A retaining portion 304 formed of an annular recess is formed on the inner circumference of the base end side (the tooth base side of the gear portion 301) of the. A member indicated by a dashed line 310 is a drive shaft that is fitted into the hollow portion of the side gear 300 and has spline teeth on the outer periphery that are spline-joined with the spline teeth 303.

As shown in FIG. 8, the cap member 305 has a cup-shaped metal main body 307 having an engaging portion 306 on its peripheral edge, and an elastically deformable film member 308 integrated with the outer periphery of the metal main body 307. The metal main body 307 is press-fitted into the hollow portion 302 so that the tip of the engaging portion 306 engages the side surface of the annular retaining portion 304 of the side gear 300, and the member 308 of the film member 308 is provided. Hollow part 3
By tightly contacting the inner peripheral surface 302a of 02, the inside of the device case and the hollow portion 302 of the side gear 300 are partitioned, and the working oil is sealed in the device case.

[0006]

However, in the cap member 305 described above, the film-shaped member 308 is in close contact with the inner peripheral surface 302a due to the elastic restoring force. Since it is prevented from leaking to the outside, it cannot be said that the sealability is sufficiently secured.

Further, since the cup-shaped metal body 307 of the cap member 305 is inserted into the hollow portion 302 of the side gear 300, the spline coupling length between the drive shaft 310 and the inner peripheral surface of the hollow portion 302 can be made sufficiently large. Cannot be secured. Therefore, the drive shaft 3
It is not possible to sufficiently secure the coupling strength between 10 and the side gear 300.

Therefore, the present invention has been made in view of the above circumstances, and surely improves the sealing property of the hydraulic oil sealed in the differential device case, and at the same time, the drive shaft and the side gears constituting the differential device are improved. It is an object of the present invention to provide an automatic transmission that can sufficiently secure the coupling strength.

[0009]

In order to achieve the above object, the invention according to claim 1 stores a transmission unit and a differential device in the same device case in which hydraulic oil is sealed, and the differential device is A side gear provided with a pinion to which power is transmitted from the speed change unit, a hollow portion and a gear portion meshing with the pinion on an outer periphery of one end side of the hollow portion, and one end from the other end side of the hollow portion of the side gear. Of the hydraulic oil from the inside of the device case to the hollow portion of the side gear, which is press-fitted toward the side and includes a drive shaft that is spline-coupled to the inner peripheral surface of the hollow portion, on one end side of the hollow portion of the side gear. In an automatic transmission including a cap member for sealing a flow, an annular groove is formed on an inner peripheral surface of one end of the hollow portion of the side gear. On the other hand, the cap member includes an elastically deformable cap body having a cup portion having a substantially C-shaped axial cross section and an annular claw portion protruding radially outward from an opening peripheral edge of the cup portion. With a structure in which a rubber layer is integrally provided on the outer periphery of the cap body, the claw portion of the cap member is engaged in the annular recessed groove, and the cup portion closes the opening on the one end side of the hollow portion, At least two seal portions, at which the rubber layer is in close contact with the inner peripheral surface of the hollow portion, are provided at positions axially separated from each other on one end side of the hollow portion.

According to the present invention, the rubber layer integrally provided on the outer periphery of the cap body of the cap member constitutes the seal portion at two axially separated positions on the one end side of the hollow portion of the side gear. It is possible to reliably prevent the hydraulic oil from flowing out to the outside along the inner peripheral surface of the hollow portion. Further, the invention according to claim 2 is the automatic transmission according to claim 1, wherein when the cap member is mounted in the hollow portion, an outer peripheral surface of the cup portion that closely adheres to an inner peripheral surface of the hollow portion The cup side rubber layer provided is the first
And a cap member provided on the outer surface of the claw portion that comes into close contact with the side surface of the groove when the drive shaft is press-fitted into the hollow portion toward one end side. The claw-side rubber layer serves as the second seal portion.

According to the present invention, the first seal portion (cup side rubber layer) provided on the outer peripheral surface of the cup portion, which is in close contact with the inner peripheral surface of the hollow portion of the side gear, and the drive shaft are directed toward the one end side in the hollow portion. The second seal part (claw-side rubber layer), which comes into close contact with the side surface of the annular groove when the cap member moves toward one end side when pressed in, along the inner peripheral surface of the hollow part of the side gear. It is possible to reliably prevent the hydraulic oil from flowing out.

Further, the invention according to claim 3 is the same as claim 1.
Or the cap member is engaged with the inner peripheral surface of the side gear so that the cup portion is not located in the hollow portion and bulges toward the one end side of the side gear. There is. According to the present invention, since the cup portion is not located in the hollow portion of the side gear, the spline teeth of the drive shaft can be deeply pressed into the hollow portion up to one end side of the side gear (near the root of the gear portion). As a result, the spline coupling length of the drive shaft and the side gear becomes long, and the coupling strength of the drive shaft and the side gear is sufficiently secured.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a skeleton diagram showing a gear train of an automatic transmission to which the present invention can be applied.
This automatic transmission has a so-called three-axis configuration and has a form of a lateral transaxle for a front engine / front drive (FF) vehicle or a rear engine / rear drive (RR) vehicle. 6th forward speed
It is equipped with a gear train that realizes the first reverse speed.

The automatic transmission has an input shaft 5 which is a first shaft arranged in parallel with each other in a transmission case 180.
0, counter shaft 401, drive shafts 453a, 4
It has a configuration in which various elements such as a transmission unit and a gear are arranged on each axis of 53b. The input shaft 50 receives torque from an engine (not shown) via the torque converter 230, and has an output side provided on the torque converter 230 side, and the counter shaft 401 is arranged parallel to the input shaft 50. The counter gear 400 meshes with the output gear of the input shaft 50.
A differential case light 4 described later that supports 3a and 453b.
The 51 is provided with a final gear 452 to which torque is transmitted via the counter gear 400 of the counter shaft 401.

The automatic transmission is provided with a transmission unit around the input shaft 50. The speed change unit includes a first planetary gear mechanism 10 that outputs a plurality of speed-changed rotations by inputting decelerated rotation and non-decelerated rotation of the input shaft 50, and the input shaft 50.
Second planetary gear mechanism 30 that decelerates and outputs the rotation of the
And the second planetary gear mechanism 30 and the first planetary gear mechanism 1
No. 0 and two different sun gears 11 and 12, respectively, which are respectively inserted and released between the first and third clutches 60 and 80 which can be freely engaged and disengaged, the input shaft 50 and the first planetary gear mechanism 10.
The second clutch 70, which can be fastened and released freely, is interposed between the carrier 14 and the first and second brakes 100 for applying a braking force to the sun gear 11 and the carrier 13 of the first planetary gear mechanism 10. And 110, and a one-way clutch 90 inserted in parallel with the second brake 110.
It has and.

First, second and third clutches 60, 70
And 80 and the first and second brakes 100 and 11
Reference numeral 0 denotes a multi-plate configuration including friction members, the first clutch 60 is disposed near the outer peripheral side of the second planetary gear mechanism 30, and the third clutch is disposed near the rear (left side in FIG. 1) thereof. 80 is arranged, the second clutch 70 is arranged at the front end portion of the mission case 180, and the first brake 10 is arranged.
0 is arranged between the first clutch 60 and the inner peripheral surface of the mission case 180, and the second brake 110 is arranged between the first planetary gear mechanism 10 and the inner peripheral surface of the mission case 180. Has been done. In addition, the one-way clutch 90 includes a first brake 100 and a second brake 110.
It is located between and.

The first planetary gear mechanism 10 is arranged near the rear (left side in FIG. 1) of the counter drive gear 170 and includes a large-diameter sun gear 11, a small-diameter sun gear 12, carriers 13, 14 and a ring gear 17. It consists of four shifting elements. The first planetary gear mechanism 10 is a long pinion 1
5 meshes with the large-diameter sun gear 11, and the short pinion 1
6 meshes with a small diameter sun gear 12, and a long pinion 15
Is a Ravigneaux type that meshes with the inner teeth of the ring gear 17.

Large-diameter sun gear 11 and small-diameter sun gear 1
Reference numeral 2 is an input element for decelerated rotation that is input from the input shaft 50 via the second planetary gear mechanism 30. That is, the small-diameter sun gear 12 is connected to the first clutch 60 and input from the second planetary gear mechanism 30. In addition, the large-diameter sun gear 11 has a third clutch 80.
Is coupled to the second planetary gear mechanism 30 and is input to the transmission case 180 by the first brake 100.

The carriers 13 and 14 support a long pinion 15 and a short pinion 16 that mesh with each other, and form a non-decelerated rotation input element to which an input from the input shaft 50 is directly made. The carrier 14 includes the second clutch 7
The carrier 13 is connected to the input shaft 50 via 0, and the carrier 13 can be fixed to the mission case 180 by the second brake 110, and can be rotated only in one direction by the one-way clutch 90. There is. Here, in the one-way clutch 90, the engagement direction is set to the reaction force torque supporting direction at the first speed and the second direction is set.
The brake 110 of FIG. Also,
The ring gear 17 forms an output element and is connected to the counter drive gear 170.
0 is located between the first planetary gear mechanism 10 and the second clutch 70, and is rotatably supported by an intermediate partition wall 195 separated from the input shaft 50, as described later. .

The second planetary gear mechanism 30 includes a sun gear 3
1, three ring gears 32 and a carrier 33. The second planetary gear mechanism 30 includes a sun gear 31 and a side cover 200 of a mission case 180, which will be described later.
Fixed to the sleeve member 210 formed in the first planetary gear mechanism, the ring gear 32 is coupled to the input shaft 50 as an input element, and the carrier 33 is an output element via the first and second clutches 60 and 70. Connected to 10.

The counter gear 400 is mounted on the counter drive gear 170 of the input shaft 50 which is fixed to the rear end side (left side in FIG. 1) of the counter shaft 401 which is parallel to the input shaft 50 and shorter than the input shaft 50. It has a large diameter counter driven gear 402 that meshes with it, and a small diameter reduction gear 403 as an output element fixed to the front end side (right side in FIG. 1) of the counter shaft 401 with respect to the counter driven gear 402. Here, both ends of the counter shaft 401 are first
And rotatably supported by the second bearings 404a and 404b. The counter gear 400 includes a counter driven gear 402 and a reduction gear 403.
The output from the input shaft 50 is decelerated, inverted and transmitted to the differential device 450 to obtain an appropriate reduction ratio.

The automatic transmission having the above structure is
6th forward speed (1ST to 6TH) based on the vehicle load in the range of the shift speed corresponding to the range selected by the driver, under the control of an electronic control unit and a hydraulic control unit (not shown),
Shifts to the first reverse speed (REV). The operation for performing the sixth forward speed and the first reverse speed is as follows. Note that FIG. 2 is a diagrammatic representation of the shift speeds achieved by engagement and disengagement of each clutch and brake (engagement with a circle represents engagement and release without a mark).

In the first speed (1ST), the first clutch 60
And the one-way clutch 90 is engaged. In this case, in the first speed, the rotation reduced from the input shaft 50 via the second planetary gear mechanism 30 is input to the small-diameter sun gear 12 via the first clutch 60, and the one-way clutch 90 is engaged so that the mission case 180 is engaged. A reaction force is applied to the carrier 14 locked to the counter drive gear 170, and the reduced rotation of the ring gear 17 at the maximum reduction ratio is output to the counter drive gear 170. In addition, since the reaction torque applied to the carrier 13 is reversed during the engine coast, the bracketed circles in FIG.
As shown by, the second brake 110 is engaged.

The second speed (2ND) is achieved by engaging the first clutch 60 and the first brake 100. In this case, from the input shaft 50 to the second planetary gear mechanism 30
The rotation reduced in speed is input to the small-diameter sun gear 12 via the first clutch 60, and the reaction force is applied to the large-diameter sun gear 11 fixed to the transmission case 180 by the engagement of the first brake 100, and the ring gear The decelerated rotation of 17 is output to the counter drive gear 170. The speed reduction ratio at this time is smaller than that in the first speed (1ST).

The third speed (3RD) is achieved by simultaneous engagement of the first clutch 60 and the third clutch 80. In this case, from the input shaft 50 to the second planetary gear mechanism 3
The rotation decelerated via 0 is simultaneously input to the large-diameter sun gear 11 and the small-diameter sun gear 12 via the third clutch 80 and the first clutch 60, and the first planetary gear mechanism 10 is directly connected. The rotation of the ring gear 17, which is the same as the input rotation to both sun gears 11 and 12, is reduced as the rotation of the input shaft 50 is reduced, and the counter drive gear 1
It is output to 70.

The fourth speed (4TH) is achieved by simultaneously engaging the first clutch 60 and the second clutch 70. In this case, the rotation decelerated from the input shaft 50 via the second planetary gear mechanism 30 is input to the small-diameter sun gear 12 via the first clutch 60 on the one hand, and the input shaft 50 on the other hand.
The non-decelerated rotation input from the second clutch 70 via the second clutch 70 is input to the carrier 14, and the intermediate rotation between the two input rotations is the rotation of the ring gear 17 slightly reduced with respect to the rotation of the input shaft 50. It is output to the counter drive gear 170.

The fifth speed (5TH) is achieved by simultaneously engaging the second clutch 70 and the third clutch 80. In this case, the rotation decelerated from the input shaft 50 via the second planetary gear mechanism 30 is input to the large-diameter sun gear 11 via the third clutch 80 on the one hand, and the input shaft 50 on the other hand.
The non-decelerated rotation input from the second clutch 70 via the second clutch 70 is input to the carrier 14, and the input shaft 50 of the ring gear 17 is input.
The rotation slightly increased from the rotation is output to the counter drive gear 170.

The sixth speed (6TH) is achieved by engaging the second clutch 70 and the first brake 100. In this case, the non-decelerated rotation is input only from the input shaft 50 to the carrier 14 via the second clutch 70, and the ring gear 17 that takes a reaction force to the sun gear 11 fixed to the transmission case 180 by the engagement of the first brake 100. The further increased rotation is output to the counter drive gear 170.

The reverse drive (REV) is achieved by engaging the third clutch 80 and the second brake 110.
In this case, the rotation reduced from the input shaft 50 via the second planetary gear mechanism 30 is input to the sun gear 11 via the third clutch 80, and the carrier fixed to the mission case 180 by the engagement of the second brake 110. The counter drive gear 1 is the reverse rotation of the ring gear 17
It is output to 70.

By the way, FIG. 3 shows a detailed structure of the differential device 450 described above. This differential device 450 includes a reduction gear 403.
The ring gear 452 meshed with the ring gear 452 and the differential case light 451 fixed to the ring gear 452 together with the differential case left 471 by the bolt 470. The differential case left 471 is formed in a flange shape,
The transmission case 180 is rotatably supported by a bearing 472 mounted on the inner wall of the mission case 180, and the differential case light 451 is rotatably supported by a bearing 473 mounted on the inner wall of the mission case 180. .

One shaft member 474 penetrating inwardly of the differential case light 451 is fixed by a pin 475, and a pinion 476 is rotatably supported on the shaft member 474. . As a result, the final gear 452, the differential case left 471, the differential case light 451, the shaft member 474, and the pin 475 integrally rotate about the drive shafts 453a and 453b.

The pinion 476 meshes with gear portions 477a and 478a formed on the base end side of a pair of side gears 477 and 478 formed in a hollow cylindrical shape. Intermediate portions 477b, 478 of the pair of side gears 477, 478
The outer peripheral surface of b is rotatably supported by the differential case left 471, and the extension portion 477 on the tip side is provided.
c and 478c are extended toward the outside of the mission case 180, respectively.

In the hollow parts of the side gears 477 and 478,
Fitting portions 477c and 478c for fitting the drive shafts 453a and 453b are formed.
O-ring grooves 477d, 4a are formed on the inner peripheral surfaces of 7a, 478b.
78d is formed in an annular shape, and an O-ring is attached to it. In addition, as shown in FIG.
The head side as one end side of 77, 478 (gear portion 477
a, 478a) and the spline teeth 47 on the inner peripheral surface
9 are formed, and drive shafts 453a, 45
Spline teeth 480 are also formed on the outer circumference of the tip side of 3b, and when the drive shafts 453a and 453b are inserted into the hollow portions of the side gears 477 and 478, the spline teeth 479 and 480 are spline-coupled. And
The side gear 47 is attached to the heads of the side gears 477 and 478.
A cap member 482 that closes the hollow portion of 7, 478 is locked, and this cap member 482 prevents the hydraulic oil sealed in the differential device 450 from leaking to the outside.

The structure of the cap member 482 and the structure of the side gear 477 for locking the cap member 482 will be described with reference to FIGS. 4 and 5. The side gear 4
Since the structure of 78 is the same as that of the side gear 477, description thereof will be omitted. The cap member 482 is composed of a hat-shaped cap body 483 and a rubber layer 484 that is integrally formed by vulcanization adhesion on the entire outside of the cap body 483.

The cap body 483 is a member made of elastically deformable metal, and has a cup portion 48 whose axial cross section is substantially C-shaped.
3a, and a claw portion 483b that has a ring shape and projects radially outward from the opening peripheral edge of the cup portion 483. The rubber layer 484 includes a claw-side rubber layer 484a at an outer peripheral portion from an outer surface of the claw portion 483b facing the cup portion 483a to a substantially middle portion in the axial direction of the cup portion 483a, and a portion other than the claw-side rubber layer 484a. Cup side rubber layer 4
And 84b.

As shown in FIG. 4, the hollow portion of the side gear 477 for locking the cap member 482 is formed by setting the diameter of the inner peripheral surface 477e at the tip of the head smaller than the outer diameter of the cap member 482. In addition, an annular convex portion 477g is formed after the inclined surface 477f is provided at a portion distant from the inner peripheral surface 477e to the inner side of the hollow portion by a predetermined distance, and the hollow portion immediately after the convex portion 477g is formed. An annular groove 477h is formed on the inner side of the portion.

The diameter of the inner peripheral surface 477e at the tip of the head is
The diameter of the cup-side rubber layer 484b of the cap member 482 is set so as to be in close contact with the inner peripheral surface 477e while elastically deforming. Further, the diameter of the top of the annular convex portion 477g is set so that the claw portion 483b of the cap member 4823 passes through while elastically deforming. The bottom diameter and width of the annular groove 477h are set so that the claw portion 483b is inserted in the elastically restored state.

As shown in FIG. 5, the cap member 482 having the above-described structure is arranged such that the cup portion 483a bulges outside the hollow portion of the side gear 477 and is separated from the spline teeth 480, while the claw portion 483b is elastic. It is deformed to pass through the annular convex portion 477g and elastically returned in the annular concave groove 477h, so that it is locked to the inner peripheral surface of the side gear 477. At this time, the cup-side rubber layer 484b of the cap member 482 comes into close contact with the inner peripheral surface 477e while elastically deforming.

Then, the drive shaft 453a is inserted into the hollow portion of the side gear 477. Here, since the O-ring is installed in the O-ring groove 477d on the inner peripheral surface of the side gear 477, the internal space of reference symbol A defined by the end surface of the drive shaft 453a and the inner peripheral surface of the cap member 482 is It becomes a closed space. Therefore, when the drive shaft 453a is inserted into the hollow portion of the side gear 477, the entire cap member 482 moves toward the tip end side of the side gear 477 (rightward in the drawing) due to the increase in the internal pressure of the closed space A.

As described above, when the entire cap member 482 moves toward the head end side of the side gear 477, as shown in FIG. 6, the claw-side rubber layer 484a integrally provided on the outer surface of the claw 483b. However, it is in close contact with the groove side surface 477 of the annular recessed groove 477h facing this. According to the differential device 450 having the above-described configuration, the two seal portions of the cap member 482 reliably prevent the outflow of the hydraulic oil from flowing out to the outside along the inner peripheral surfaces of the hollow portions of the side gears 477 and 478. You can

That is, the cup-side rubber layer 484b provided on the outer peripheral surface of the cup portion 483a of the cap member 482.
However, by elastically deforming, the side gear 477 comes into close contact with the inner peripheral surface 477e at the head end of the side gear 477 to form a first seal portion.
Further, the claw-side rubber layer 484a provided on the outer surface of the claw portion 483b of the cap member 482 is provided with the side gears 477, 47.
The ring-shaped groove 477h of No. 8 comes into close contact with the groove side surface 477 to form a second seal portion. This surely prevents the hydraulic oil in the transmission case 180 from flowing out to the outside along the inner peripheral surfaces of the hollow portions of the side gears 477 and 478.

Further, the cap member 482 of the present embodiment.
At the tip of the head of the side gears 477 and 478,
83a is positioned, that is, the cup portion 483a is locked so as not to enter the hollow portions of the side gears 477 and 478. Therefore, the spline teeth 480 of the drive shafts 453a and 453b are inserted deeply into the hollow portions near the roots of the gear portions 477a and 478a of the side gears 477 and 478, and the drive shaft 453
Since the spline coupling length of a and the side gear 477 (drive shaft 453b and side gear 478) becomes long, the coupling strength between the drive shaft and the side gear can be sufficiently secured.

In the above embodiment, the automatic transmission is configured as a gear train that realizes 6 forward speeds, but the present invention is not limited to this, and automatic transmissions of 5 forward speeds or lower or 7 speeds or higher are performed. The present invention can be applied to a machine.

[0044]

As described above, according to the invention of claim 1, when the claw portion of the cap member is engaged with the annular groove formed in the inner peripheral surface of the hollow portion of the side gear on the one end side,
Since the rubber layer integrally provided on the outer periphery of the cap body that constitutes the cap member constitutes the seal portion at two axially distant positions on one end side of the hollow portion, the rubber layer is formed on the inner peripheral surface of the hollow portion of the side gear. It is possible to reliably prevent the hydraulic oil from flowing out along the outside.

According to the second aspect of the invention, the drive shaft is provided inside the hollow portion, and the first seal portion made of the cup-side rubber layer provided on the outer peripheral surface of the cup portion which is in close contact with the inner peripheral surface of the hollow portion. The inner circumference of the hollow part of the side gear, together with the second seal part made of the claw-side rubber layer that comes into close contact with the side surface of the annular groove when the cap member moves toward the one end side when press-fitted toward the one end side. It is possible to reliably prevent the hydraulic fluid from flowing out along the surface.

Further, according to the third aspect of the invention, the cap member is engaged with the inner peripheral surface of the side gear so that the cup portion is not located in the hollow portion and bulges toward the one end side of the side gear. As a result, the spline teeth of the drive shaft can be pressed deeply into the hollow part up to one end side of the side gear (near the root of the gear part), and the spline coupling length of the drive shaft and side gear becomes longer. It is possible to sufficiently secure the coupling strength between the drive shaft and the side gear.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an automatic transmission to which the present invention is applied.

FIG. 2 is a diagram showing an operation of the automatic transmission.

FIG. 3 is an enlarged cross-sectional view showing the inside of the differential device of the present invention.

FIG. 4 is a diagram showing a main part of a differential device of the present invention.

FIG. 5 is a diagram showing a state in which a cap member is attached to a hollow portion of a side gear of a differential device of the present invention, and a drive shaft is press-fitted therein.

FIG. 6 is a view showing a state in which press fitting of a drive shaft is completed in a hollow portion of a side gear.

FIG. 7 is a view showing a state in which a cap member is attached to a hollow portion of a side gear of a conventional differential device.

FIG. 8 is a diagram showing a main part of FIG.

[Explanation of symbols]

10 First planetary gear mechanism 30 Second planetary gear mechanism 180 mission case (equipment case) 450 differential device 451 differential case light 452 Final Gear 453a, 453b drive shaft 471 differential case left 476 Pinion 477,478 Side gear 477a, 478a Gear part 477c, 478c Fitting part 477e inner peripheral surface 477f inclined surface 477g convex 477h concave groove 477 groove side 479,480 spline teeth 482 cap member 483 cap body 483a cup part 483b claw 484 rubber layer 484b Cup side rubber layer 484a Claw side rubber layer

Continued front page    F term (reference) 3J027 FA21 FA37 FB02 FB03 HA01                       HA03 HB07 HC03 HC13                 3J040 AA01 AA11 EA41 FA05                 3J063 AB12 AC01 BB01 BB11 CA05                       CD67

Claims (3)

[Claims] 1. A transmission unit and a differential device are housed in the same device case in which hydraulic oil is sealed,
The differential device includes a pinion to which power is transmitted from the speed change unit, a side gear having a hollow portion and a gear portion meshing with the pinion on an outer periphery of one end side of the hollow portion, and the other side of the hollow portion of the side gear. The drive shaft is press-fitted from the end side toward the one end side, and includes a drive shaft that is spline-coupled to the inner peripheral surface of the hollow portion, at one end side of the hollow portion of the side gear, from the inside of the device case to the hollow portion of the side gear. In an automatic transmission including a cap member that seals the flow of hydraulic oil, an annular groove is formed on an inner peripheral surface of the side gear on one end side of the hollow portion, while the cap member is a shaft. An elastically deformable cap body having a cup portion having a substantially C-shaped cross section and an annular claw portion protruding radially outward from an opening peripheral edge of the cup portion, A rubber layer is integrally provided on the outer periphery of the cap body, the claw portion of the cap member is engaged in the annular groove, and the cup portion closes the opening on the one end side of the hollow portion. An automatic transmission characterized in that at least two seal portions, which are in close contact with the inner peripheral surface of the hollow portion, are provided at axially separated positions on one end side of the hollow portion. 2. A cup-side rubber layer provided on the outer peripheral surface of the cup portion, which is in close contact with the inner peripheral surface of the hollow portion when the cap member is mounted in the hollow portion, is a first seal portion, and When the drive shaft is press-fitted into the hollow portion toward one end side, the cap member moves toward the one end side, and the claw-side rubber layer provided on the outer surface of the claw portion that comes into close contact with the side surface of the groove is 2. The automatic transmission according to claim 1, wherein the seal portion is two. 3. The cup portion is not located in the hollow portion, and bulges toward one end side of the side gear,
The automatic transmission according to claim 1, wherein the cap member is engaged with an inner peripheral surface of the side gear.