JP2002130438A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a shaft directional dimension and a radial directional dimension of an automatic transmission, and to sufficiently lubricate frictional engaging elements. SOLUTION: This automatic transmission has the first frictional engaging element, the second frictional engaging element, a rotatably arranged hydraulic servo drum for constituting a hydraulic servo C-3 for engaging and disengaging the first frictional engaging element, and a hub for supporting a friction member 67 of the second frictional engaging element. The hydraulic servo drum has an outer peripheral wall 42, an inner peripheral wall 43 and a bottom wall 44. The hub is formed in a prescribed position of an inner diameter from the outer peripheral wall 42 in the radial direction of the bottom wall 44 by superposing at least a part on the inner peripheral wall 43 in the shaft direction. In this case, since the hub is formed by superposing at least a part on the inner peripheral wall 43 in the shaft direction, the shaft directional dimension of the automatic transmission 11 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an automatic transmission.

[0002]

2. Description of the Related Art Conventionally, an automatic transmission used for a vehicle such as an automobile has a transmission having a planetary gear unit. The transmission includes a plurality of frictional engagement elements such as a clutch and a brake, and the frictional engagement elements are disengaged and engaged in a predetermined combination to select from gear elements such as a sun gear, a ring gear, and a carrier of the planetary gear unit. The rotation is output in a desired manner to achieve a plurality of gears.

The friction engagement elements are disengaged by operating a hydraulic servo of a hydraulic circuit. The hydraulic servo includes a hydraulic servo drum having an outer peripheral wall and an inner peripheral wall, an annular piston slidably fitted into the hydraulic servo drum, and the like. The piston is moved by supplying and discharging oil to and from an apply oil chamber formed between the piston and the piston, and the friction engagement element disposed opposite to the piston is disengaged.

The hydraulic circuit is provided with various solenoid valves, switching valves, and the like. When a solenoid of a predetermined solenoid valve is turned on / off, the predetermined switching valve is switched and connected to the switching valve. Hydraulic pressure is supplied to and discharged from the hydraulic servo.

[0005] A clutch drum is used as a hydraulic servo drum in a hydraulic servo for disengaging the clutch.

[0006]

However, in the conventional automatic transmission, in order to selectively fix the clutch drum to the automatic transmission case, the clutch drum and the automatic transmission case need to be fixed. When a brake is provided, or in order to selectively fix the clutch drum to another rotating member, when a clutch is provided between the clutch drum and another rotating member, the clutch drum and If the brake or clutch hub is disposed along the axial direction, the axial dimension will increase.

Therefore, it is conceivable to dispose the hub radially outward of the clutch drum. In this case, however, the radial size of the automatic transmission increases. Further, if it is attempted to avoid the radial dimension of the automatic transmission from increasing, the radial dimension of the clutch drum must be reduced, which makes it difficult to secure the capacity of the clutch. In addition, if the brake hub is provided radially outward of the clutch drum, it becomes impossible to sufficiently lubricate the frictional engagement elements of the brake or the clutch.

The present invention solves the above-mentioned problems of the conventional automatic transmission, can reduce the axial dimension and the radial dimension, and can sufficiently lubricate the friction engagement elements. The purpose is to provide a machine.

[0009]

For this purpose, in an automatic transmission according to the present invention, a first frictional engagement element and a second frictional engagement element are rotatably disposed, and the first frictional engagement element and the second frictional engagement element are rotatably provided. A hydraulic servo drum constituting a hydraulic servo for engaging and disengaging the friction engagement element, and a hub for supporting the friction member of the second friction engagement element.

The hydraulic servo drum has an outer peripheral wall extending in the axial direction, an inner peripheral wall extending in the axial direction, and a bottom wall connecting the outer peripheral wall and the inner peripheral wall.

Further, the hub is formed at a predetermined position inside the outer peripheral wall in the radial direction of the bottom wall, at least partly overlapping the inner peripheral wall in the axial direction.

In another automatic transmission according to the present invention, an oil sump is formed by the hub and a part of the bottom wall.

In still another automatic transmission according to the present invention,
Further, ribs are formed at a plurality of positions in the circumferential direction of the bottom wall so as to extend in the radial direction.

In still another automatic transmission according to the present invention,
Further, a through hole is formed through the hub.

In still another automatic transmission according to the present invention,
Furthermore, the through-hole is formed at a plurality of positions in the circumferential direction at a plurality of positions in the axial direction, and the number of the through-holes at a position near the bottom wall among the plurality of positions is
The number is larger than the number of through holes at a position apart from the bottom wall among the plurality of positions.

In still another automatic transmission according to the present invention,
Further, a deflecting means for deflecting the oil supplied from the oil supply source toward the bottom wall is provided.

In still another automatic transmission according to the present invention,
Further, a part of the bottom wall includes a horizontal wall formed substantially parallel to the inner peripheral wall.

An oil reservoir is formed between the hub and the horizontal wall.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a main part of an automatic transmission according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of the automatic transmission according to the embodiment of the present invention, and FIG. 3 is an automatic transmission according to the embodiment of the present invention. It is a figure showing an operation table of a transmission.

In the figure, reference numeral 11 denotes an automatic transmission, and 12 denotes a torque converter for transmitting rotation in the direction of arrow A generated by driving an engine (not shown) to a transmission 13.

The torque converter 12 includes a pump impeller 15 connected to an output shaft 14 from which the rotation of the engine is output, a turbine runner 17 connected to an input shaft 16 for inputting rotation to a transmission 13, The stator 19 mounted on the one-way clutch 18 locks the output shaft 14 and the input shaft 1 when predetermined conditions are satisfied.
6 and a damper device (not shown) and the like.

The transmission 13 has a first clutch C1, a second clutch C2, a third clutch C3, a first brake B1 and a second brake B2 as friction engagement elements. The transmission 13 has first and second planetary gear units 25 and 26. The first planetary gear unit 25 includes a sun gear S1 as a gear element, and a ring gear concentrically arranged with the sun gear S1. R1, a pinion P1 meshed (engaged) with the sun gear S1 and the ring gear R1, and a carrier CR1 rotatably supporting the pinion P1. The second planetary gear unit 26 includes a sun gear S as a gear element.
2, S3, a ring gear R2 concentrically arranged with the sun gears S2, S3, the sun gear S2 and the ring gear R2.
A pinion P2 meshed with the pinion P2, a pinion P3 meshed with the sun gear S3 and the pinion P2, and a carrier CR2 rotatably supporting the pinions P2 and P3.
Is provided. In the present embodiment, the first clutch B3 is used as the first frictional engagement element by the third clutch C3.
Constitutes a second frictional engagement element.

The sun gear S1 and the automatic transmission case 30 are connected, the ring gear R1 and the input shaft 16 are connected, and the carrier CR1 and the sun gear S3 are connected via a first clutch C1. , The carrier CR1 and the sun gear S2 are connected via a third clutch C3.

Further, the ring gear R2 and the output shaft 27 are connected, and the carrier CR2 and the automatic transmission case 30 are connected to each other.
The carrier CR is connected via a one-way clutch F1 and a second brake B2 disposed in parallel with each other.
2 and the input shaft 16 are connected via the second clutch C2.

The one-way clutch F1 becomes free during the 1-2 shift, as the first brake B1 is engaged.

In the automatic transmission 11 having the above configuration, the input shaft 16 and the sun gear S2 are connected via the first planetary gear unit 25 and the third clutch C3, and the sun gear S2 and the automatic transmission case 30 are connected to each other. 1 brake B
1 are connected. Therefore, the third clutch C3
, The rotation reduced in the first planetary gear unit 25 is input to the sun gear S2, and the sun gear S2 is stopped by engaging the first brake B1. Also, the first clutch C1
, The rotation reduced in the first planetary gear unit 25 is input to the sun gear S3. Then, the input shaft 16 and the carrier CR2 are connected via the second clutch C2, and the second clutch C2
, The rotation that cannot be decelerated is input from the input shaft 16 to the carrier CR2. Further, the output shaft 27 and the ring gear R2 are connected, and the ring gear R
2 outputs a rotation.

Next, the operation of the automatic transmission 11 configured as described above will be described.

In FIG. 3, P is a parking range, R
EV is the reverse range, N is the neutral range, 1ST is the first speed in the forward range, 2ND is the second speed in the forward range, 3RD.
Is the third speed in the forward range, 4TH is the fourth speed in the forward range, 5T
H indicates the fifth speed in the forward range, and 6TH indicates the sixth speed in the forward range. Each of the ranges is selected by operating speed selection means such as a shift lever.

The circles indicate the first clutch C1, the second clutch C2, the third clutch C3, the first brake B1, and the second clutch C1.
The state where the brake B2 is engaged indicates the state where the one-way clutch F1 is locked. △ represents the second brake B2 when the engine brakes.
Shows a state where is engaged.

At the first speed in the forward range, when the first clutch C1 is engaged, the rotation input from the input shaft 16 to the first planetary gear unit 25, and the rotation reduced by the first planetary gear unit 25, First
It is input to the sun gear S3 via the clutch C1. Accordingly, one-way clutch F1 is locked, rotation of carrier CR2 is prevented, and as a result, ring gear R
The rotation reduced at the maximum reduction ratio from 2 to the output shaft 27
Is output to

When the first clutch C1 and the first brake B1 are engaged in the second speed in the forward range, the input is input from the input shaft 16 to the first planetary gear unit 25, and the first planetary gear unit 25 reduces the speed. The rotated rotation is input to the sun gear S3 via the first clutch C1. At this time, the sun gear S2 is fixed with the engagement of the first brake B1, so that the rotation reduced from the ring gear R2 at a reduction ratio smaller than the reduction ratio of the first speed is output to the output shaft 27.

When the first clutch C1 and the third clutch C3 are engaged at the third speed in the forward range, the input is input from the input shaft 16 to the first planetary gear unit 25, and the speed is reduced at the first planetary gear unit 25. The rotated rotation is input to the sun gear S3 via the first clutch C1, and is input to the sun gear S2 via the third clutch C3, so that the second planetary gear unit 26 is directly connected. Therefore, each sun gear S
2. The rotation input to S3 is transmitted to the ring gear R2 as it is, and the rotation reduced from the ring gear R2 at a reduction ratio smaller than the reduction ratio of the second speed is output to the output shaft 27.

When the first clutch C1 and the second clutch C2 are engaged at the fourth speed in the forward range, the input is input from the input shaft 16 to the first planetary gear unit 25, and the first planetary gear unit 25 reduces the speed. The rotated rotation is input to the sun gear S3 via the first clutch C1, and the rotation that cannot be reduced from the input shaft 16 is transmitted to the carrier CR2 via the second clutch C2.
Is input to Therefore, the intermediate rotation between the rotation input to the sun gear S3 and the rotation input to the carrier CR2,
The rotation reduced from the ring gear R2 at a reduction ratio smaller than the third reduction ratio is output to the output shaft 27.

When the second clutch C2 and the third clutch C3 are engaged at the fifth speed in the forward range, the input is input from the input shaft 16 to the first planetary gear unit 25, and the first planetary gear unit 25 reduces the speed. The rotated rotation is input to the sun gear S2 via the third clutch C3, and the rotation that cannot be reduced from the input shaft 16 is transmitted to the carrier CR2 via the second clutch C2.
Is input to As a result, from the ring gear R2 to the input shaft 1
The rotation slightly increased in speed with respect to the rotation of No. 6 is output to the output shaft 27.

When the second clutch C2 and the first brake B1 are engaged at the sixth speed in the forward range, rotation that cannot be decelerated from the input shaft 16 is input to the carrier CR2 via the second clutch C2. . At this time, since the sun gear S2 is fixed with the engagement of the first brake B1, the rotation further increased from the rotation of the input shaft 16 is output from the ring gear R2 to the output shaft 27.

When the third clutch C3 and the second brake B2 are engaged in the reverse range, the input shaft 16
Is input to the first planetary gear unit 25, and the rotation reduced in the first planetary gear unit 25 is input to the sun gear S2 via the third clutch C3. At this time, since the carrier CR2 is fixed with the engagement of the second brake B2, the ring gear R2
Then, the rotation that is reversed with respect to the rotation of the input shaft 16 is output to the output shaft 27.

Next, the main part of the automatic transmission will be described.

In FIG. 1, reference numeral 37 denotes a sleeve which extends in the axial direction of the transmission 13 and is fixed to the automatic transmission case 30. Reference numeral 38 denotes a tubular portion of a pump cover of an oil pump (not shown). The input shaft 16 is rotatably disposed in the sleeve 37. The sleeve 3
The first planetary gear unit 25 is disposed radially outward of the rear end (right end in FIG. 1) of the sleeve 7, and the rear end of the sleeve 37 and the sun gear S1 are spline-engaged.

Further, a third clutch C3 is arranged further radially outward of the first planetary gear unit 25. The third clutch C3 includes a friction member 35 formed by alternately disposing outer thin plates 33 and inner thin plates 34, and a hydraulic servo C-3.

The hydraulic servo C-3 is a clutch drum 36 as a hydraulic servo drum rotatably supported by the washers 55 and 56 with respect to the cylindrical portion 38, and is slidably fitted into the clutch drum 36. An annular piston 45, a cancel plate 46 locked in the clutch drum 36 in the piston 45, and a cancel plate 46 disposed between the piston 45 and the cancel plate 46 so that the cancel plate 46 faces the clutch drum 36. And an apply oil chamber 48 is formed between the clutch drum 36 and the piston 45.

The clutch drum 36 has an outer peripheral wall 42 extending axially along the inner peripheral surface of the automatic transmission case 30, an inner peripheral wall 43 extending axially along the cylindrical portion 38,
And a bottom wall 44 connecting the outer peripheral wall 42 and the inner peripheral wall 43 and extending substantially in the radial direction. The bottom wall 44 includes the inner peripheral wall 4.
3, a vertical wall portion 57 extending radially from a front end (left end in FIG. 1), and a first inclined portion extending obliquely rearward (rightward in FIG. 1) from an outer peripheral edge of the vertical wall portion 57. A wall portion 58, a vertical wall portion 59 extending radially outward from the outer peripheral edge of the inclined wall portion 58, a horizontal wall portion 61 extending rearward from the outer peripheral edge of the vertical wall portion 59, and the horizontal An inclined wall portion 62 as a second inclined portion extending obliquely rearward from the rear end of the wall portion 61 is provided. An annular projection 71 is formed on the inner peripheral edge of the vertical wall portion 57 so as to project forward (to the left in FIG. 1), and a cylindrical shape is formed radially outward of the projection 71. An annular washer 41 made of resin for receiving a thrust load applied to the clutch drum 36 is disposed adjacent to the large-diameter portion 72 of the portion 38.

The hydraulic circuit is provided with various solenoid valves, switching valves, and the like. A predetermined switching valve and an apply oil chamber 48 are connected to an oil passage 5 formed on the outer peripheral surface of the sleeve 37.
1, and through oil passages 52 to 54 formed through the cylindrical portion 38, the washer 55, and the inner peripheral wall 43.

Accordingly, when the solenoid of a predetermined solenoid valve is turned on / off and a predetermined switching valve is switched, oil is supplied to and discharged from the apply oil chamber 48, and the piston 45 is moved in the axial direction. The third clutch C <b> 3 disposed opposite to the first clutch 45 can be disengaged. For this purpose, the outer peripheral edge of the outer thin plate 33 and the inner peripheral surface of the clutch drum 36 are spline-engaged, and the inner peripheral edge of the inner thin plate 34 and the outer peripheral surface of the carrier CR1 are spline-engaged. The inner thin plate 34 is disposed so as to be movable in the axial direction. Further, the tip of the piston 45 and the outer thin plate 33 are opposed to each other.

A first brake B1 is provided between the clutch drum 36 and the automatic transmission case 30, and the first brake B1 is provided in the second and sixth speed ranges of the forward range.
1 by engaging the clutch drum 36
Are fixed to the automatic transmission case 30. Therefore, at a predetermined position in the radial direction of the bottom wall 44 from the outer peripheral wall 42, in the present embodiment, near the lower end of the inclined wall portion 62, integrally with the clutch drum 36, An annular brake hub 63 as a hub is formed so as to protrude forward from near the lower end of the wall portion 62 toward the front. In this case, the radial position of the brake hub 63,
The radial position of the tip of the piston 45 is made substantially equal. Further, the axial position of the front end of the brake hub 63 and the axial position of the front end of the inner peripheral wall 43 are made equal. And
At a plurality of positions in the circumferential direction of the front end face (the left end face in FIG. 1) of the bottom wall 44, it is extended in the radial direction and along the inclined wall 58, the vertical wall 59, and the horizontal wall 61. A rib 74 is formed. Also, the brake hub 63 and the bottom wall 4
An annular oil sump 78 is formed between a part of 4 and the horizontal wall 61 in the present embodiment.

The first brake B1 is formed by alternately arranging outer thin plates 65 and inner thin plates 66, and includes a friction member 67 supported by the brake hub 63 and a hydraulic servo (not shown). The outer peripheral edge of the outer thin plate 65 and the automatic transmission case 30
The outer thin plate 65 and the inner thin plate 66 are disposed so as to be movable in the axial direction by spline engaging the inner peripheral surface of the inner thin plate 66 and spline engaging the inner peripheral edge of the inner thin plate 66 with the outer peripheral surface of the brake hub 63. Is done.

In order to lubricate the first brake B1, the large diameter portion 72 of the small diameter portion 73 of the cylindrical portion 38 is used.
An oil groove 68 is formed at a portion adjacent to the oil groove 68. The oil groove 68 and the oil passage 51 are connected by an oil passage (not shown). Therefore, the oil supplied from an oil supply source (not shown), for example, a predetermined hydraulic pressure adjustment valve via the oil passage 51 passes through the oil groove 68, and the protrusion 71
And a gap (gap) between the front end face of the annular washer 41 and the rear end face (the right end face in FIG. 1) of the large-diameter portion 72,
It is supplied radially outward from the annular washer 41. Subsequently, the oil is guided toward the clutch drum 36 by the guide plate 75, flows directly radially outward, and is supplied to the inner peripheral surface of the brake hub 63. It is sent to the outer peripheral surface side of the brake hub 63 through the through holes 76 and 77 formed at the position. In addition,
The guide plate 75 is provided between the front end face of the annular washer 41 and the large diameter portion 7.
2, a flat portion 81, a locking piece 82 bent forward in the vicinity of the inner peripheral surface of the flat portion 81, and an outer peripheral surface of the flat portion 81. The locking piece 82 is bent obliquely rearward and deflects the oil toward the bottom wall 44 as a deflecting means. The guide plate 75 is stopped.

In this case, a part of the oil sent to the clutch drum 36 side by the deflecting portion 83 directly reaches the inner peripheral surface of the brake hub 63, and the remaining oil flows radially outward along the rib 74. And is supplied to the oil sump 78. The through holes 76 and 77 are formed at a plurality of positions in the circumferential direction at each position in the axial direction, and the through holes 77 at a position near the bottom wall 44 among the plurality of positions.
Is made larger than the number of the through holes 76 at positions apart from the bottom wall 44 among the plurality of positions. In addition, the through hole 77 is provided so as to face the oil reservoir 78. Therefore, the oil is evenly sent to the inner peripheral surface of the brake hub 63 and then evenly sent to the outer peripheral surface of the brake hub 63.
The first brake B1 can be sufficiently lubricated.

As described above, the clutch drum 36 and the brake hub 63 are disposed at least partially, in this embodiment, substantially entirely, in an axially overlapping (overlapping) relationship with each other. Therefore, the axial dimension of the automatic transmission 11 can be reduced. Further, the brake hub 6 is disposed radially outward of the clutch drum 36.
Since there is no need to dispose 3, the radial size of the automatic transmission 11 can be reduced. Therefore, the radial dimension of the clutch drum 36 can be made sufficiently large, so that the radial dimension of the piston 45 can be made large, and it is easy to secure the capacity of the third clutch C3. Since the number of the outer thin plates 33 and the number of the inner thin plates 34 can be reduced accordingly, the axial size of the automatic transmission 11 can be reduced. In addition, the brake hub 63 is formed so as to protrude from the vicinity of the lower end of the inclined wall portion 62, and a space is formed between the bottom wall 44 and the brake hub 63 radially inward of the brake hub 63, so that the oil There is nothing blocking the supply to the hub 63. Therefore, the first brake B1 can be sufficiently lubricated.

In the present embodiment, the brake hub 63 as a hub is formed on the clutch drum 36. However, in order to selectively fix the clutch drum to another rotating member, the clutch hub is provided. When a clutch is provided between the drum and another rotating member, a clutch hub as a hub can be formed on the clutch drum.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0052]

As described above in detail, according to the present invention, in the automatic transmission, the first frictional engagement element and
A second frictional engagement element rotatably disposed with the first frictional engagement element;
And a hub for supporting the friction member of the second friction engagement element.

The hydraulic servo drum has an outer peripheral wall extending in the axial direction, an inner peripheral wall extending in the axial direction, and a bottom wall connecting the outer peripheral wall and the inner peripheral wall.

Further, the hub is formed at a predetermined position inside the outer peripheral wall in the radial direction of the bottom wall, at least partially overlapping the inner peripheral wall in the axial direction.

In this case, the hub is formed at a predetermined position inside the outer peripheral wall in the radial direction of the bottom wall and at least partially overlapped with the inner peripheral wall in the axial direction. The axial dimension can be reduced. Also, since there is no need to dispose a hub radially outward of the hydraulic servo drum, the radial size of the automatic transmission can be reduced.

Therefore, the radial dimension of the hydraulic servo drum can be made sufficiently large, so that the radial dimension of the piston can be made large, and the capacity of the friction engagement element can be easily secured. Since the number of the outer thin plate and the inner thin plate constituting the friction member can be reduced correspondingly, the axial dimension of the automatic transmission can be reduced. In addition, since the hub is formed so as to protrude from the bottom wall at a predetermined position, and the oil reservoir is formed by the hub, the second frictional engagement element can be sufficiently lubricated.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of an automatic transmission according to an embodiment of the present invention.

FIG. 3 is a diagram showing an operation table of the automatic transmission according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Automatic transmission 36 Clutch drum 42 Outer peripheral wall 43 Inner peripheral wall 44 Bottom wall 63 Brake hub 67 Friction member 74 Rib 76, 77 Through hole 78 Oil reservoir 83 Deflection part B1 First brake C3 Third clutch C-3 Hydraulic servo

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[Procedure amendment]

[Submission date] November 2, 2000 (200.11.
2)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoru Kasuya 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd.・ Within AW Co., Ltd. (72) Inventor Hiroshi Kato 10 at Takane, Fujii-cho, Anjo-city, Aichi Prefecture Aisin Co., Ltd. (72) Masahiro Ida 10, Takane, Fujii-cho, Anjo-city, Aichi Prefecture Aishi F term in NW Corporation (reference) 3J063 AA02 AB31 AC04 BA03 BB41 CB36 CD41 3J067 AA01 AC12 AC53 EA03 FB33 FB83 GA01

Claims (7)

[Claims] A first friction engagement element, a second friction engagement element, and a hydraulic pressure rotatably disposed to constitute a hydraulic servo for disengaging the first friction engagement element. A hydraulic drum having a servo drum and a hub for supporting a friction member of a second friction engagement element, wherein the hydraulic servo drum has an outer peripheral wall extending in an axial direction, an inner peripheral wall extending in an axial direction, and the outer peripheral wall; A bottom wall connecting the inner peripheral wall and the hub is provided,
An automatic transmission, wherein at least a part of the bottom wall is overlapped with the inner peripheral wall in the axial direction at a predetermined position inside the outer peripheral wall in the radial direction. 2. The automatic transmission according to claim 1, wherein an oil reservoir is formed by the hub and a part of the bottom wall. 3. The automatic transmission according to claim 1, wherein ribs are formed to extend in a radial direction at a plurality of positions in a circumferential direction of the bottom wall. 4. The automatic transmission according to claim 1, wherein a through hole is formed through the hub. 5. The through hole is formed at a plurality of positions in a circumferential direction at a plurality of positions in an axial direction,
The automatic transmission according to claim 4, wherein the number of through holes at a position near the bottom wall among the plurality of positions is larger than the number of through holes at a position away from the bottom wall among the plurality of positions. 6. The automatic transmission according to claim 1, further comprising a deflecting means for deflecting the oil supplied from the oil supply source toward the bottom wall. 7. The automatic machine according to claim 2, wherein a part of the bottom wall includes a horizontal wall formed substantially parallel to the inner peripheral wall, and an oil reservoir is formed between the hub and the horizontal wall. transmission.