JPH04131544A - Automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the generation of shock caused by grip change between a brake and a clutch at the time of switching speed change stages with a simple structure by connecting two clutches and one-way clutch, disposed parallel to a brake, to one another by a connecting member. CONSTITUTION:An input shaft 15 is connected to a first connecting member 16 through a first clutch C1 and also to a second connecting member 16' through a second clutch C2. A third clutch C3 and a third one-way clutch F0 are interposed between the first connecting member 16 and the ring gear R1 of a single planetary gear 10, and a fourth clutch C0 is interposed between the first connecting member 16 and a large ring gear R2. A fifth clutch C4 and a first one-way clutch F1 are interposed between a sun gear S and the second connecting member 16', and the second connecting member 16' can be locked by a first brake B1. A second brake B2 and a second one-way clutch F2 are further interposed between the large ring gear R2 and a case 17.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to automatic transmissions for automobiles.

(Prior Art) Conventionally, an automatic transmission for an automobile has a plurality of planetary gear sets, and friction engagement elements such as brakes and clutches connected to each element of the planetary gear set. Each gear is achieved by selectively engaging elements.

For example, there has been provided a system in which four clutches and three brakes are provided, and each friction engagement element is selectively engaged (U.S. Pat. No. 4,086
, No. 827).

However, in this type of automatic transmission, the number of brakes is large, so the axial dimension becomes large. Therefore, brakes with a reduced number of brakes and a smaller axial dimension have been proposed.

In this case, the 4-speed gear mechanism of the automatic transmission with 4 forward speeds has a planetary gear unit formed by combining a single planetary gear and a dual planetary gear, and the sun gears of both brake gears of the planetary gear unit are connected to each other. are integrally formed, each binion has a common carrier, and the carrier supporting the above-mentioned binion and the binion that meshes with the ring gear of the dual planetary gear is also integrally constructed.

The input shaft extending from the output member of the torque converter is connected to the connecting member via the first clutch CI and to the sun gear via the second clutch C2, and the input shaft is connected to the connecting member and the single planetary gear. A third clutch C3 and a one-way clutch FO are interposed between the IJ ring gear, and a fourth clutch CO is interposed between the connecting member and the large ring gear.

Further, the sun gear is configured to be locked by a first brake B1 consisting of a handbrake, and a second brake B2 and a one-way clutch F are interposed between the large ring gear and the case. ing. Further, the carrier is connected to an output gear located approximately in the center of the transmission gear mechanism.

In the automatic transmission having the above configuration, the first clutch C1 is engaged in the first gear, the first brake B1 is engaged in addition to the first clutch C1 in the second gear, and the first brake B1 is engaged in the third gear.
Brake B1 is released, and the third clutch C3 and fourth clutch CO are engaged, and in fourth gear, the third clutch C3 is released and the first brake B1 is engaged.

When in 1st gear, one-way clutch F1 and one-way clutch FO are engaged, but when shifting from 1st to 2nd gear, one-way clutch F1 overruns to prevent the occurrence of shock due to clutch switching. There is.

In addition, when shifting from 2nd speed to 3rd speed, the timing of supplying oil to the brake release hydraulic chamber of the hydraulic servo that engages and disengages the first brake B1, and the timing of supplying oil to the brake release hydraulic chamber of the hydraulic servo that engages and disengages the fourth clutch CO. By adjusting the timing of oil supply, shocks caused by changing grips are prevented.

When shifting from 3rd gear to 4th gear, when the third clutch C3 is released, the second one-way clutch F
The third speed state is maintained by O, and the locking of the first brake B1 is delayed by hydraulic control to prevent shocks caused by changing grips.

(Problem to be Solved by the Invention) However, in the automatic transmission having the above configuration, when shifting from 2nd speed to 3rd speed, the brake release hydraulic chamber of the hydraulic servo that engages and disengages the first brake B1 is By adjusting the timing of supplying oil and the timing of supplying oil to the hydraulic servo that engages and disengages the fourth clutch CO, the generation of wrinkles and burrs due to clutch changes is prevented, so the hydraulic control device Not only is this complicated, but it is also difficult to obtain an optimal soft feeling under all driving conditions and vehicles.

In addition, it is necessary to re-engage the first brake B1, which was released when shifting from 2nd gear to 3rd gear, when shifting from 3rd gear to 4th gear, and by repeating engagement and disengagement, the first brake B1 (band brake ) The stress applied to the band constituting Bl changes, resulting in a decrease in durability.

In particular, the vehicle travels frequently in the 3rd and 4th gears, during which engagement and disengagement of the first brake BLO is repeated, so durability tends to deteriorate.

The present invention solves the J point between the above conventional automatic transmissions, and
To provide an automatic transmission capable of preventing the occurrence of shock due to switching of the brake and clutch when changing each gear stage with a simple flIa, and improving the durability of a handbrake. purpose.

(Means for Solving the Problems) For this purpose, in the automatic transmission of the present invention, forward running
It has a brake that is released in 1st gear and is always engaged in 2nd gear or higher, and two clutches and one one-way clutch that are arranged in parallel with the brake, and these are connected. connected by members.

One of the clutches engages and disengages between the coupling member and the input shaft and is engaged when the vehicle is not traveling forward, and the one-way clutch engages the coupling member and the plastic gear unit when the brake is engaged. The other clutch engages between the connecting member and the sun gear of the planetary gear unit to increase the speed from the non-directly connected state of the planetary gear unit, and the other clutch engages between the connecting member and the sun gear of the planetary gear unit when the brake is engaged. At the same time, the speed of the planetary gear unit is increased from the directly connected state.

(Operations and Effects of the Invention) According to the present invention, as described above, there is a brake that is released in the first speed of forward travel and is always engaged in the second speed or higher, and a brake that is disposed in parallel with the brake. It has two clutches and one one-way clutch, which are connected by a connecting member.

One of the clutches engages and disengages between the coupling member and the input shaft, and is engaged when the brake is engaged, and the one-way clutch engages the coupling member and the planetary gear unit when the brake is engaged. The other clutch engages between the sun gear and increases the speed from the non-directly connected state of the brake gear unit, and the other clutch engages between the coupling member and the sun gear of the planetary gear unit while the brake is engaged. When engaged, the speed of the planetary gear unit is increased from the directly connected state.

Therefore, when traveling in 1st forward speed, none of the brakes, the two clutches, and the one-way clutch are engaged, and when traveling in 2nd speed, the 5-button I/- key is engaged and the one-way clutch is engaged; The sun gear of the planetary gear unit, which was in a directly connected state, is now fixed, increasing the rotation speed on the output side.

When the vehicle is running in third gear, the brake is kept engaged and the gear unit I is directly connected to output high-speed rotation. When running in fourth speed, the other clutch is engaged while the brake remains engaged, and the sun gear of the planetary gear unit, which was in the directly connected state, is fixed, increasing the rotation speed on the output side.

Furthermore, during reverse, one of the clutches is engaged, the rotation of the input shaft is sent to the sun gear side of the planetary gear unit, and reverse rotation is output.

Therefore, the brake remains engaged when shifting from 2nd to 3rd gear, which not only simplifies the hydraulic control system, but also provides optimal shift feeling under all driving conditions and vehicles. I can do it.

In addition, since it is no longer necessary to re-engage the brake released when shifting from 2nd to 3rd gear when shifting from 3rd to 4th gear, it prevents the durability of the hand from decreasing due to repeated engagement and disengagement. can do.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a skeleton of an automatic transmission according to the present invention, and FIG. 2 is a sectional view of the automatic transmission according to the present invention.

The 4-speed automatic transmission A to which the present invention is applied includes a torque converter 50, a 4-speed gear lateral 1, a speed reduction mechanism 51, and a differential device 52, each having a torque converter 50 and a rotary clutch clutch L/C.

The 4-speed gear machine lateral 1 has a planetary gear unit 12 formed by combining a single planetary gear 10 and a dual planetary gear 11, and the sun gear Sl of the single planetary gear 10 and the sun gear S2 of the dual planetary gear 11 are integrated. The sun gear S is formed by forming the sun gear S.

Furthermore, a binion P meshing with the sun gears S1 and S2
The carrier CR is common to i and Pi', and the carrier CR that supports the binion P2 that meshes with the ring gear (hereinafter referred to as "large ring gear") Ii2 of the dual planetary gear 11 and the nion P1' is also integrated. It is composed of

The input shaft 15 extending from the output member of the torque converter 50 is connected to the first connecting member 16 via the first clutch C1, and the input shaft 15 is connected to the first connecting member 16 via the first clutch C1.
It is connected to the second connecting member 16' via.

Further, a third clutch C3 and a third one-way clutch FO are interposed between the first connecting member 16 and the IJ songer (hereinafter referred to as "small ring gear J") R1 of the single-plane gear 10. Further, a fourth clutch CO is interposed between the connecting member 16 and the large ring gear R2.

Further, a fifth clutch C4 and a first one-way clutch Fl are connected between the sun gear S and the second connecting member 16'.
is interposed therebetween, and the second connecting member 16' is configured to be able to be stopped by a first brake B1 consisting of a handbrake.

Furthermore, there is a second gear between the large ring gear R2 and the case 17.
A brake B2 and a second one-way clutch F2 are interposed. Further, the carrier CR is connected to an output gear 13 located approximately in the center of the transmission gear machine 11.

Further, the reducer [51 has a counter shaft 54 that is rotatably supported by the case, and the counter shaft 54 has a large gear 53 and a small gear 55 that are always meshed with the output gear 13. Fixed. Further, the differential device 52 includes a differential binion 56 and left and right side binions 57a and 57b that mesh with each other, and the side binions 57a and 57b are fixed to left and right front axles 59a and 59b, respectively. Further, the differential binion 56 is supported by a differential case 60 that is rotatably supported by the case, and a ring gear 61 that is always meshed with the small gear 55 is attached to the differential case 60.

Next, the operation of the automatic transmission of the present invention will be explained with reference to FIG.

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

In the first gear in the forward running state, the first clutch C
1 is engaged, and the second and third one-way clutches F
2. FO is engaged, and the rotation of the input shaft 15 is transmitted to the small ring gear R1 via the first clutch C1 and the third one-way clutch FO, and in this state, the rotation of the large ring gear R2 is transmitted by the second one-way clutch F2. Since rotation is blocked, carrier C1? while letting sun gear S idle? is significantly decelerated, and the decelerated rotation is output gear 1.
It is taken out from 3.

The rotation of the output gear 13 is decelerated by a speed reduction mechanism 51, and further transmitted to left and right front axles 59a, 59b by a differential device 52.

In addition, in the second speed state, the first brake B1 is engaged in addition to the first clutch CI, the idling sun gear S is stopped by the first one-way clutch Fl, and the third Since the one-way clutch FO is engaged, the rotation of the input shaft 15 is caused by the first clutch CI and the third clutch CI.
Since the sun gear S is stopped by the first brake B1 and the first one-way clutch F1, the rotation of the small ring gear R1 causes the large ring gear R2 to idle. Career CI? It is taken out as a 2nd speed rotation.

Note that during the shift from the first speed to the second speed, the second one-way clutch F2 overruns to prevent shift shock from occurring due to clutch change.

Furthermore, in the third speed state, the fourth clutch CO is engaged in addition to the first clutch C1 and the first brake B1, and the rotation of the input shaft 15 is controlled by the third one-way clutch F.
The signal is transmitted to the small ring gear R1 via the fourth clutch CO, and is also transmitted to the large ring gear R2 via the fourth clutch CO, so that the planetary gear unit 12 is directly connected. The integral rotation obtained thereby is taken out from the carrier CR to the output gear 13. Also, when coasting, the third
The third clutch C3 is engaged to prevent overrun of the one-way clutch FO.

At this time, the above-mentioned integral rotation is transmitted to the sun gear S, thereby causing the first one-way clutch Fl to overrun, thereby preventing the shift J7 from occurring due to the clutch change.

Next, in the fourth speed state, the first clutch C1, the fourth
In addition to the clutch CO and the first brake B1, the fifth clutch C4 is switched to the locked state, and the rotation of the sun gear S is stopped. Further, the third clutch C3 is
It is released prior to engagement of the fifth clutch C4.

At this time, the rotation of the input shaft 15 is transmitted to the large ring gear R2 via the fourth clutch CO, and the rotation of the input shaft 15 is transmitted to the large ring gear R2 via the fourth clutch CO.
4 locks the sun gear S, the rotation of the large ring gear R2 causes the carrier CR to rotate at high speed while causing the small ring gear R1 to idle, and this rotation is transmitted to the output gear 13.

Note that the third one-way clutch FO overruns when shifting from third to fourth speed, thereby preventing shift shock from occurring due to clutch change.

On the other hand, when downshifting from 4th speed to 3rd speed, the planetary gear unit 12 rotates integrally by releasing the fifth clutch C4, and the integral rotation is taken out from the carrier Cal to the output gear 13. At this time, the third one-way clutch FO is switched from overrun to locked, making it possible to prevent shift shock from occurring.

Also, when downshifting from 3rd gear to 2nd gear, the fourth clutch CO is released and the planetary gear unit
The locked state is released, and at this time, the first one-way clutch Fl is switched from overrun to locked to stop the sun gear S, and the second speed is taken out from the output gear 13.

When downshifting from second speed to first speed, the first brake B1 is released, the sun gear S becomes idle, and the second one-way clutch F2 is engaged.

When kicking down from 4th gear to 2nd gear, the fourth clutch CO is released, the third one-way clutch FO is switched from overrun to locked, and the rotation of the input shaft 15 is controlled by the small ring gear R1. transmitted to.

At this time, the fifth clutch C4 is also released, but since the first brake B1 is engaged, the first one-way clutch F1 is engaged to stop the sun gear S, and the output gear 13
2nd gear is taken out.

Next, during engine braking at l speed, the second one-way clutch F2 and the third one-way clutch F2
Since the motor O overruns and coasts, the second brake B2 and the third clutch C3 are engaged. Also,
Similarly, during 2nd speed engine braking, the first one-way clutch Fl and the third one-way clutch F
O overruns, so the fifth clutch C4 and the third
Clutch C3 is engaged.

On the other hand, in the R range, the second clutch C2, the fifth clutch C4, and the second brake B2 are engaged, and the rotation of the input shaft 15 is controlled by the second clutch C2 and the fifth clutch C.
4 to the sun gear S, and since the large ring gear R2 is stopped by the second brake B2, the rotation of the sun gear S is transmitted to the carrier CR while causing the small ring gear R1 to idle in the opposite direction. and the reverse rotation is taken out from the output gear 13.

Further, at this time, the first one-way clutch F1 is engaged to prevent shift shock from occurring.

In the automatic transmission with the above configuration, the fourth clutch CO and the third clutch C3 are arranged adjacent to each other, and the inner ring, spring, and spring retainer of both clutches are shared, and the axial dimension is shortened. .

Further, the second clutch C2 and the fifth clutch C4 are also arranged adjacently, and the inner rings of both clutches,
The spring and spring retainer are shared and have a reduced axial dimension.

The arrangement of the second clutch C2 and the fifth clutch C4 will be explained.

FIG. 4 is a sectional view of essential parts of the automatic transmission of the present invention.

In the figure, 16' is a drum-shaped second connecting member disposed adjacent to the oil pump cover 65, and the second clutch C2 and the fifth clutch are disposed in the second connecting member 16'. Clutch C4 is arranged adjacently.

Further, the second connecting member 16' is an inner ring 66.
and the Araku cylinder 6 fixed to the inner cylinder ring 66.
The inner ring 66 is slidably disposed around the outer periphery of the sleeve fixed to the oil pump cover 65. And the above inner ring 6
The hub 6 of the oil pump case 65 is disposed on the inner circumferential side of the
A large-diameter portion 64a of a stator shaft 64 is spline-fitted to the further inner circumferential side of 5a, and is rotatably supported via a hair ring 63. The stator shaft 64 is connected to an inner race of a one-way clutch within the torque converter 50 (FIG. 2).

The inner cylinder 66 and sleeve 68 are made of steel to improve friction resistance during relative rotation, and the oil pump cover 65 is made of aluminum. Further, the inner cylinder 66 has a cylindrical portion having a long axial dimension on the outer peripheral side, and the first and second annular pistons 72 and 74 are formed on the outer surface of the cylindrical portion.
It frictionally slides with the sleeve 68 on the inner surface. Further, the inner peripheral side has a cylindrical portion having a short axial dimension, and slides on the stator shaft 64 via a hair ring 63 on the inner surface thereof. The above shape is formed by cutting, and the first and second annular pistons 72, 74
Improved concentricity with

On the other hand, a folded portion 67a is formed on two outer peripheral sides of the outer cylinder 67, and the surface of the folded portion 67a is opposed to the hand of the first brake B1 to form a friction surface. The outer cylinder 67 is made by press molding.

A first annular piston 72 is slidably disposed in a first annular cylinder chamber 71 formed within the second connecting member 16', thereby forming a hydraulic servo C4 for the fifth clutch C4. be done.

The first annular piston 72 has a dish-shaped cross section, and together with the inner cylinder 66, a second annular cylinder chamber 73 is formed. A second annular piston 74 is slidably disposed within the second annular cylinder chamber 73 to form a hydraulic servo C2 for the second clutch C2.

Then, the second club is inserted through the sleeve 68.

Each hydraulic servo C, , C of the clutch C2 and the fifth clutch C4
.

Oil is supplied and discharged to and from.

Further, a spring retainer 75 is provided upright in the inner cylinder 66 so as to face the second annular piston 74.
the spring retainer 75 and the second annular piston 7
A spring 76 is disposed between the four.

On the other hand, a fifth clutch C is provided in the outer cylinder 67.
A thin plate 78 for No. 4 is spline-fitted, and movement in the axial direction is restricted by a snap ring 79. Further, a contact portion 80 of the first annular piston 72 is disposed opposite to the thin plate 7 for the fifth clutch C4.

The corresponding contact portion 80 is spline-fitted to the outer cylinder 67 and is only allowed to move in the axial direction.

Then, by supplying oil into the hydraulic servo C4 for the fifth clutch C4, the first annular piston 72 moves in the axial direction, and the thin plate 7 for the fifth clutch C4 moves in the axial direction.
8 is engaged and disengaged.

Further, a thin plate 82 for the second clutch C2 is spline-fitted to the inner periphery of the cylindrical portion 81 of the first annular piston 72, and movement in the axial direction is restricted by a snap ring 83. Further, the second annular piston 74 is disposed so as to be in contact with the thin plate 82 for the second clutch C2.

Then, by supplying oil into the hydraulic servo C2 for the second clutch C2, the second annular piston 74 moves in the axial direction, and the one plate 8 for the second clutch C2 moves in the axial direction.
2 is disengaged.

Here, the second clutch C2 and the fifth clutch C4 can be operated independently. The second clutch C2 is engaged only when the vehicle is traveling in reverse, and at this time the fifth clutch C4 is also engaged at the same time.

The clutch flange 85 of the second clutch C2 is
It is fixed to the large diameter portion 15a of the input shaft 15, and when the second clutch C2 is engaged, the rotation of the human power shaft 15 is transferred to the outer cylinder 67 via the first annular piston 72.
transmitted to.

The large-diameter portion 15a faces the large-diameter portion 64a of the stator shaft 64 at one end thereof, and is slidably abutted against the thrust via the ring 86.

Moreover, it faces the sun gear shaft 87 on the opposite side,
They are slidably abutted via a thrust hair ring 88. Note that 89 is the above-mentioned thrust hair ring race on the 8th day.

Further, the outer cylinder 67 of the second connecting member 16'
A plate-shaped flange 91 extending in the inner circumferential direction is provided on the inner circumference of the end of the
are spline-fitted, and the flange 91 is fixed to an outer race 92 of the first one-way clutch F1. Therefore, the first one-way clutch F1 and the second connecting member 16' are connected. On the other hand, the inner race 93 of the first one-way clutch F1 is spline-fitted to the sun gear shaft 87, and connects the second connecting member 16' and the sun gear S.

By the way, a clutch flange 94 is disposed on the inner peripheral side of the thin plate 78 of the fifth clutch C4, and the clutch flange 94 is fixed to the inner race 93 of the first one-way clutch Fl. That is, by engaging the fifth clutch C4, the second connecting member 1
6' is connected to sun gear S.

Washers 96 and 97 are provided at both ends of the outer race 92 of the first one-way clutch F1, and between the outer race 92 and the output gear 13, the outer race 9
2 and the clutch flange 94 are allowed.

At two points, the outer race 92 is in contact with the output gear 13 via the washer 96. Therefore, in order to ensure the concentricity between the outer race 92 and the inner race 93 and to prevent the sprag from rolling out or rolling in during free rotation, the inner race 93 is made movable in the axial direction.

A notch 89a is formed in the inner peripheral end of the inner race 93, and the notch 89a and the thrust hair ring 8 are connected to each other.
A gap is formed between the race 89 of No. 8 and the race 89 of No. 8.

As described above, the inner race 93 is spline-fitted to the sun gear shaft 87 and is movable in the axial direction.

Moreover, since the gap is formed, when the sun gear shaft 87 formed integrally with the sun gear S moves in the axial direction, it is not subjected to an axial thrust load.

Furthermore, an oil passage 21 for supplying lubricating oil is formed in the interior of the input shaft 15 in the axial direction, and oil grooves 22, 23, and 24 extend from the oil passage 21 in the radial direction. The above oil groove 22
The lubricating oil supplied from the input shaft 15 and the sun gear shaft 87
It is sent to the oil channel between. The sun gear shaft 87 and the input shaft 15
A bushing 25 is disposed between them and rotatably supports the sun gear shaft 87, and the bushing 25 is lubricated by lubricating oil supplied from the oil groove 22.

Further, an oil groove 26 is formed in a portion of the sun gear shaft 87 that faces the first one-way clutch F1.
The sun gear shaft 87 and the inner race 93 are connected through the oil groove 26.
The spline fittings between the two are lubricated.

Furthermore, the inner race 93 has oil grooves 2 in the radial direction.
7 is formed, and lubricating oil is sent to the sprag via the cedar oil groove 27 for lubrication.

Further, the lubricating oil sent radially outward from the oil groove 23 lubricates the thrust hair ring 88 and passes through the gap between the clutch flanges 85 and 94 to the clutch hub 28.
The oil is sent to the oil sump formed on the inner circumference of the clutch hub 2.
The oil is supplied to the thin plate 78 for the fifth clutch C4 through an oil groove (not shown) drilled in the fifth clutch C4, and cools the thin plate 78 for the fifth clutch C4. Then, it is sent to the inner periphery of the folded part 67a of the second connecting member 16', and the folded part 6
7a through the oil groove 29 formed in the first brake B1.
cooling the friction surface.

On the other hand, the lubricating oil sent in the radial direction through the oil groove 24 is sent to the thrust hair ring 86 via an oil path between the input shaft 15 and the stator shaft 64, and cools the thrust flange 86. After that, the lubricating oil is applied to the clutch flange 8.
5 to an oil reservoir formed on the inner circumference of the clutch hub 31, and is sent to the thin plate 82 for the second clutch C2 via an oil groove (not shown) formed in the clutch hub 31,
The thin plate 82 for the second clutch C2 is cooled. The second
The lubricating oil after cooling the first plate 82 for clutch C2 is
The oil is sent to the inner circumference of the folded part 67a of the second connecting member 16', and the first
The friction surface of brake B1 is cooled.

Note that the present invention is not limited to the above embodiments (
Various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the skeleton of the automatic transmission of the present invention, FIG. 2 is a sectional view of the automatic transmission of the present invention, FIG. 3 is a diagram showing an operation table of the automatic transmission of the present invention, and FIG. 1 is a sectional view of a main part of an automatic transmission according to the present invention. A... 4-speed automatic transmission, B1... first brake,
B2...second brake, CO...fourth clutch, C1...first clutch, C2...second clutch, C3...third clutch, C4...third clutch 5 clutch, FO...Third one-way clutch, Fl...
・First one-way clutch, F2... Second one-way clutch, 1... 4-speed gear mechanism, 10...
Single planetary gear, 11... Dual planetary gear, 13... Output gear, 15... Input shaft, 17
...Case, 66...Inner case, 67...
Araku cylinder, 72.74... Annular piston, 85
．． 94... Taranochi flange, 91... Flange,
92...Outer lace, 93...Inner lace. Patent applicant: Aisin ADA Co., Ltd. Agent: Makoto Kawai (2 others), Figure 3

Claims (1)

[Claims] A brake that is released in 1st forward speed and always engaged in 2nd or higher speeds, a connecting member that is engaged and released by the brake, two clutches and one clutch that are disposed in parallel with the connecting member. one-way clutch, one of the clutches engages and disengages between the coupling member and the input shaft, and is engaged except when traveling forward, and the one-way clutch is configured to engage the coupling member and the input shaft when the brake is engaged. The other clutch engages between the connecting member and the sun gear of the planetary gear unit to increase the speed of the planetary gear unit from a non-directly connected state, and the other clutch engages between the connecting member and the sun gear of the planetary gear unit when the brake is engaged. 1. An automatic transmission characterized in that the automatic transmission engages the planetary gear unit and increases speed from a directly connected state of the planetary gear unit.