JP2001349392A - Automatic transmission mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage transmission mechanism capable of setting appropriate gear ratio of the whole transmission mechanism and a reduction gear ratio step of each gear stage so as to satisfy demand as an automobile and attaining miniaturization. SOLUTION: This automatic transmission mechanism comprises a pair of ravigneaux-type planetary gears RP, and a carrier CR2 of the planetary gear RP is integrated. First to sixth gears and reverse gear shown in the velocity diagram can be obtained by motion of each of clutches C-1 to C-3 and brakes B-1 to B-3 shown in the motion diagram. Appropriate gear ratio width and reduction gear ratio step are obtained by setting as shown in the figure of the gear ratio λ.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission mechanism mounted on a motor vehicle and, more particularly, to an automatic transmission mechanism (gear train) capable of performing a multi-speed shift such as a forward fifth speed and a sixth speed.

[0002]

2. Description of the Related Art In recent years, automobiles have been required to be downsized, have high quietness, improve fuel efficiency, and have high output and efficiency, and accordingly, automatic transmissions have also been required to have multiple stages and downsizing. I have.

Conventionally, in order to increase the number of stages of an automatic transmission, a combination of a three-speed main transmission mechanism and a second-speed or third-speed auxiliary transmission mechanism obtains five or more forward gears. The main transmission mechanism and the auxiliary transmission mechanism are arranged on different shafts and are interlocked by a counter gear, thereby achieving compactness in the axial direction.

[0004]

However, the combination of the main transmission mechanism and the auxiliary transmission mechanism can achieve the above-mentioned required vehicle performance, even if a multi-speed transmission such as five forward speeds can be obtained. On the other hand, it is difficult to appropriately set the gear ratio of the entire transmission and the gear ratio step of each gear, and it is also difficult to satisfy sufficient compactness.

Accordingly, the present invention provides a multi-stage system which can set a proper gear ratio of the entire speed change mechanism and a gear ratio step of each speed stage in order to satisfy the requirements as an automobile, and can also improve compactness. It is an object to provide a transmission mechanism.

[0006]

The present invention according to claim 1 (see FIGS. 1 and 2) has one long pinion (P1).
, A planetary gear unit (RP) having at least three gear ratios, an input unit (IN), and an output unit (O).
And a plurality of frictional engagement elements capable of changing a transmission path of the planetary gear unit (RP) interposed between the first clutch (C-3) and the first clutch (C-3). , A second clutch (C-1), a third clutch (C-2), a first brake (B-1 in FIG. 1, B-2 in FIG. 2), and a second brake (B-B in FIG. 1). 3, B- of FIG.
5) and the third brake (B-2 in FIG. 1, B-4 in FIG. 2)
And the planetary gear unit (RP) includes:
The first clutch (C-3) is connected to the input portion (IN) via the first clutch (C-3), and the first brake (B-
1. First sun gear (S2) connected to B-2) in FIG.
And the second clutch (C-1) is connected to the input section (IN).
And a second sun gear (S3) connected through the third clutch (C-2) to the input portion (IN), and the second brake (B-3 in FIG. 1). FIG.
Carrier (CR2) connected to B-5) of the
A first ring gear (R2) connected to a brake (B-2 in FIG. 1, B-4 in FIG. 2); and a second ring gear (R3) connected to the output section (OUT). An automatic transmission mechanism characterized in that at least five forward speeds and one reverse speed are achieved by switching between the first, second and third clutches and the first, second and third brakes.

According to a second aspect of the present invention (see FIG. 2), the plurality of friction engagement elements include a fourth brake (B-1),
A fifth brake (B-3) and the first brake (B-
A first one-way clutch (F-1) which is arranged in parallel with 2) and is freely engageable by the fourth brake (B-1).
A second one-way clutch (F-2) disposed in parallel with the third brake (B-4) and capable of being engaged by the fifth brake (B-3);
-5) and a third one-way clutch (F
-3), the automatic transmission mechanism according to claim 1 having the following.

According to a third aspect of the present invention (see FIGS. 1 and 2), the planetary gear unit (RP) includes a pinion (P3) between the carrier (CR2) and the second ring gear (R3). And the pinion (P3) has
3. The automatic transmission mechanism according to claim 2, wherein the rotation of the input section (IN) is lower than the rotation of the input section (IN).

According to a fourth aspect of the present invention (see FIGS. 1 and 2), the plurality of friction engagement elements (C-1 to C-3 in FIG. 1) are provided.
And B-1 to B-3, C-1 to C-3 and B-1 in FIG.
To B-5 and F-1 to F-3) are arranged intensively on the input side of the planetary gear unit (RP).
An automatic transmission mechanism according to claim 2 or 3.

According to a fifth aspect of the present invention (see FIG. 2), the first, second and third one-way clutches (F-1 to F-
The third according to any one of claims 2 to 4, wherein the third brake is disposed on the inner diameter side of the first, second, third, fourth, and fifth brakes (B-1 to B-5). It is in the automatic transmission mechanism.

According to a sixth aspect of the present invention (see FIG. 2), the carrier (CR2) is formed integrally with an inner race of the third one-way clutch (F-3). The automatic transmission mechanism according to any one of the above.

According to a seventh aspect of the present invention (see FIG. 2), the first sun gear (S2) integrally forms an inner race of the first one-way clutch (F-1).
An automatic transmission mechanism according to any one of claims 2 to 6.

According to an eighth aspect of the present invention (see FIG. 2), the first ring gear (R2) integrally forms an inner race of the second one-way clutch (F-2). 8. The automatic transmission mechanism according to any one of items 7 to 7.

According to a ninth aspect of the present invention (see FIG. 2), the first one-way clutch (F-1) is engaged at a relatively middle speed (for example, third speed), and the first ring gear (R2) is engaged. )
The automatic transmission mechanism according to any one of claims 2 to 8, wherein rotation in one direction is restricted.

[0015] The reference numerals in parentheses are for the purpose of comparison with the drawings, but they are for convenience of understanding of the invention, and are not intended to limit the scope of the claims. It has no effect.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In each figure, a skeleton diagram of the gear train, an operation table, a gear ratio, and a speed diagram thereof are shown, which schematically show a skeleton portion of each automatic transmission. It is needless to say that a one-way clutch or the like may be arranged in accordance with the speed ratio, and the speed diagram is not necessarily described on a scale corresponding to the gear ratio. Also, in each automatic transmission mechanism, a torque converter is disposed between the input side and the engine, and a differential device, a counter gear, a simple transmission, and the like are disposed on the output side,
The entirety constitutes a vehicle automatic transmission.

The automatic transmission shown in FIG. 1 has a set of Ravigneaux-type planetary RPs. The planetary gears include a common long pinion P1, a sun gear S3 and a ring gear R2 which mesh directly with the long pinion.
A sun gear S2 meshing via a short pinion P2; and a ring gear R3 meshing via a short pinion P3.

An input shaft (hereinafter simply referred to as an "input shaft") IN, which is an input portion, is connected to a sun gear S3 via a clutch C-1 and to a carrier CR2 via a clutch C-2.
An output shaft (hereinafter, simply referred to as an “output shaft”) OUT, which is an output unit, is connected to the ring gear R3 via the clutch C-3 and the sun gear S2 via the clutch C-3. The brake B-1 is connected to the sun gear S2, the brake B-2 is connected to the ring gear R2, and the brake B-3 is connected to the carrier CR2.

The automatic transmission mechanism shown in FIG. 1 requires only one set of Ravigneaux type planetary gears, has only one carrier, has a simple and compact structure, and has a gear ratio of λ1.
(S3 / R3) = 0.286, λ2 (S2 / R2) =
By setting 0.252 and λ3 (S3 / R2) = 0.256, an appropriate gear ratio width and gear ratio step can be obtained.

Next, the automatic transmission mechanism shown in FIG. 2 will be described in detail with reference to the drawings. The automatic transmission mechanism shown in FIG. 2 is a partial modification of the automatic transmission mechanism shown in FIG.

As shown in the skeleton diagram of FIG. 2, the automatic transmission mechanism includes a pair of Ravigneaux type planetary gear units RP. Planetary gear RP
Has a (first) sun gear S2, a (second) sun gear S3, a carrier CR2, a (first) ring gear R2, and a (second) ring gear R3. The sun gear S2 is (first)
The input shaft IN is freely engageable with the clutch C-3. The sun gear S2 is provided with a (first) brake B-
2 and can be fixed freely (4th)
The rotation in one direction can be fixed freely by engaging the (first) one-way clutch F-1 which can be freely engaged by the brake B-1. The sun gear S3 is freely engageable with the input shaft IN by the (second) clutch C-1. The (first) ring gear R2 is connected to the (fifth) brake B-
(3) is connected to the one-way clutch F-2 to restrict rotation in one direction, and is connected to the (third) brake B-4 to be fixed freely. ing. The carrier CR2 has a (third) clutch C
-2 is connected to the input shaft IN. The carrier CR2 is connected to a (second) brake B-5 so as to be freely fixed, and is connected to a (third) one-way clutch F-3 to restrict rotation in one direction. The ring gear R3 is connected to the output shaft (output unit) OU
Connected to T.

The connected planetary gear unit RP has a long pinion P1 which is a common pinion and a sun gear S.
3. It is configured to directly mesh with the ring gear R2, connect to the sun gear S2 via the short pinion P2, and connect to the ring gear R3 via the short pinion P3. One long pinion P1 and two short pinions P2 One carrier CR2 made of P3 is integrally formed. That is, the sun gear S2, the short pinion P2, the long pinion P1, the ring gear R2 and the sun gear S3 constitute a planetary gear unit of a Ravigneaux type, and the sun gear S3, the long pinion P1, the short pinion P3 and the ring gear R3 constitute a double planetary gear. Planetary gear unit R
P has a form in which a Ravigneaux type planetary gear unit and a double planetary are integrally formed. This makes it possible to reduce the size, improve the mountability on vehicles, and reduce the number of parts. Note that a pinion P2 is provided between the carrier CR2 and the sun gear S2, and a pinion P3 is provided between the carrier CR2 and the ring gear R3.

When the present automatic transmission mechanism is actually constructed, the inner race of the one-way clutch F-3 can be integrally formed with, for example, a flange portion extending from the carrier CR2, so that it can be integrally processed. For example, it is possible to eliminate the necessity of welding another member, thereby reducing man-hours, reducing the number of parts, and reducing the cost of the automatic transmission mechanism.
Similarly, when the automatic transmission mechanism is actually configured, the inner race of the one-way clutch F-1 is
Since it can be configured integrally with the sun gear S2 and can be used in common, it is possible to reduce the number of parts and the number of parts by eliminating the need to weld another member, for example.
The cost of the automatic transmission mechanism can be reduced. Further, similarly, when the present automatic transmission mechanism is actually configured, the inner race of the one-way clutch F-2 can be integrally formed with, for example, a hub portion extending from the ring gear R2 so that the inner race can be integrally processed. For example, the need for welding another member is eliminated, so that the man-hour can be reduced, the number of parts can be reduced, and the cost of the automatic transmission mechanism can be reduced.

Next, the operation of the automatic transmission mechanism will be described with reference to the operation table and the speed diagram of FIG. The ratio of the number of teeth is λ1 (S3 / R3) = 0.286, λ2 (S3 / R3).
R2) = 0.257, λ3 (S2 / R2) = 0.25
7, respectively.

In the first speed, the clutch C-1 is engaged to input the input rotation from the input shaft IN to the sun gear S3. On the other hand, the one-way clutch F-3 is engaged to
2. Fix one-way rotation. Then, the input rotation of the sun gear S3 and the fixed carrier CR2 are connected to the ring gear R.
3 to output a normal rotation with a gear ratio of 3.500.
At the time of engine braking, the brake B-5 is locked to fix the carrier CR2, and the state of the first speed is maintained.

In the second speed, the clutch C-1 is engaged to input the input rotation from the input shaft IN to the sun gear S3. On the other hand, the one-way clutch F-
2 to fix the rotation of the ring gear R2 in one direction. Then, the input rotation of the sun gear S3 and the fixed ring gear R2 are connected to the ring gear R3 via the carrier CR2.
And outputs a normal rotation with a gear ratio of 2.316. During engine braking, the brake B-4 is locked, the ring gear R2 is fixed, and the state of the second speed is maintained.

In the third speed, the clutch C-1 is engaged to input the input rotation from the input shaft IN to the sun gear S3. On the other hand, the one-way clutch F-
1 is engaged to fix the rotation of the sun gear S2 in one direction. Then, the input rotation of the sun gear S3 and the fixed sun gear S2 are input to the ring gear R3 via the carrier CR2, and the normal rotation with a gear ratio of 1.556 is output. During engine braking, the brake B-2 is locked to fix the sun gear S2, and the third speed state is maintained.

In the fourth speed, the clutch C-1 is engaged to input the input rotation to the sun gear S3, and the clutch C-2
And input the input rotation to the carrier CR2. As a result, the sun gear S3 and the carrier CR2 have the same forward rotation, that is, the directly connected rotation is input to the ring gear R3, and the forward rotation with a gear ratio of 1.000 is output.

In the fifth speed, the clutch C-2 is engaged to input the input rotation from the input shaft IN to the carrier CR2. On the other hand, the brake B-2 is engaged to fix the rotation of the sun gear S2. Then, the fixed sun gear S2 causes the speed increase from the input rotation of the carrier CR2 to be performed by the ring gear R3.
To output a normal rotation with a gear ratio of 0.778.

In the sixth speed, the clutch C-2 is engaged to input the input rotation from the input shaft IN to the carrier CR2. On the other hand, the brake B-4 is engaged, and the ring gear R2
Fix the rotation of. Then, the fixed ring gear R2
As a result, the speed increase rotation from the input rotation of the carrier CR2 is input to the ring gear R3, and the normal rotation with the gear ratio of 0.474 is output.

In reverse, the clutch C-3 is engaged to input the input rotation from the input shaft IN to the sun gear S2. On the other hand, the brake B-5 is locked to fix the carrier CR2. Then, the input rotation of the sun gear S3 is input to the ring gear R3 as reverse rotation via the fixed carrier CR2, and the reverse rotation with a gear ratio of 3.500 is output.

As described above, the automatic transmission mechanism shown in FIG. 2 can obtain an appropriate gear ratio, a gear ratio step, and a gear ratio width of 4.500 from the 1st to the 5th to 6th speeds.
Coupled with the possibility of high-speed or six-speed multi-speed shifting,
Improvements in fuel economy can also be made possible. In addition, the present automatic transmission mechanism performs the speed change in the form of the one-way clutches F-1, F-2, and F-3 in the first to third speeds and the reverse speed, so that, for example, the clutch or the brake is re-engaged ( (Shift), the shift can be performed smoothly.

Since the above automatic transmission mechanism has the above-described configuration, it can be configured as a carrier between a double planetary gear and a Ravigneaux type planetary gear unit with one carrier CR2 of the planetary gear unit RP. An automatic transmission mechanism constituted by a double planetary gear and a Ravigneaux type planetary gear unit can be constituted by a set of planetary gear units RP. This makes it possible to reduce the size, improve the mountability on vehicles, and reduce the number of parts.

The automatic transmission mechanism has a planetary gear unit RP disposed on the output side. In the automatic transmission mechanism shown in FIG. 1, the clutches C-1, C-2, C-3 and the brakes B-1, B-3 are provided. 2, the clutches C-1, C-2, C-3 and the brakes B-1, B-2, B-3, B-4, B-5 in the automatic transmission shown in FIG. And the one-way clutches F-1, F-2, F-3 can be arranged on the input side. That is, since the plurality of friction engagement elements are arranged on the input side separately from the planetary gear unit RP, the plurality of friction engagement elements can be arranged in a large space without the planetary gear unit RP. Thereby, when the automatic transmission mechanism is actually configured, for example, a clutch, a brake, and a one-way clutch are multiplexed (for example, an inner friction plate is arranged on the outer periphery of one drum member, and an outer friction plate is arranged on the inner periphery). (A structure in which the other provided drum member is further disposed on the outer periphery). Further, since no friction engagement element is provided on the outer diameter side of the planetary gear unit RP, the automatic transmission mechanism can be made compact in the radial direction.

In the automatic transmission shown in FIG.
The one-way clutches F-1, F-2, and F-3 serve as brakes B-
1, B-2, B-3, B-4, and B-5, which can be disposed in a vacant space, that is, a so-called dead space, having an efficient arrangement structure. Can be Thereby, the automatic transmission mechanism can be made compact.

Further, the one-way clutch F-1 is engaged at the third speed, which is a relatively middle speed, so that the one-way clutch F-1 carries a small amount of torque, and can be made relatively small. Thereby, when the automatic transmission mechanism is actually configured, the one-way clutch F-1 can be disposed, for example, in an empty space, so-called dead space, and the one-way clutch F-1 A so-called double structure in which F-3 can be provided can be provided. Therefore, an efficient arrangement structure is possible, and the automatic transmission mechanism can be made compact.

Next, the rotation speed of the pinion in the automatic transmission mechanism will be described with reference to FIG. FIG.
FIG. 3 is a diagram illustrating a rotation speed ratio of a pinion with respect to an input rotation speed in the automatic transmission mechanism illustrated in FIG. 2, wherein a rotation speed ratio of a pinion P3 based on a tooth ratio λ1 and a rotation speed ratio of a pinion P1 based on a tooth ratio λ2; , The pinion P based on the gear ratio λ3
2 are respectively shown. As shown in FIG. 3, at the fifth forward speed except the sixth speed and the first reverse speed, the rotation speed ratio of each pinion P1, P2, P3 is 0.800 or less, that is, 0 with respect to the rotation speed of the input shaft IN. .8 times or less. In particular, in the pinion P3 which always transmits torque, the rotation speed ratio is 0.800 in the first speed, the rotation speed ratio is 0.594 in the second speed, and the rotation speed ratio is 0.5 in the third speed.
In the 400th and 4th speeds, the rotation speed ratio is 0.000, in the 5th speed, the rotation speed ratio is 0.800, and in reverse, the rotation speed ratio is -0.800, that is, the pinion P3
Can have a low rotation relative to the input rotation. Thereby, in the case where the present automatic transmission mechanism is actually configured, by configuring so as to achieve the fifth forward speed and the first reverse speed, it is possible to improve the durability of, for example, a bearing that supports the pinion P3, Not only that, but also other members can reduce deterioration over time and improve durability. Note that the automatic transmission mechanism shown in FIG. 1 can also be configured such that the rotation of the pinion is lower than the input rotation, and the same effect can be obtained.

[0038]

According to the first aspect of the present invention, the gear ratio width of the speed change mechanism for achieving the fifth forward speed and the first reverse speed and the gear ratio steps of each shift speed are determined by the overall structure of the gear train. Although it is possible to set an appropriate value that matches the requirements, for example, one carrier consisting of one long pinion and two short pinions can be integrally configured, so that the size can be reduced, the vehicle mountability can be improved, and the number of parts can be reduced. It is possible to obtain an automatic transmission mechanism capable of reducing the number of times.

According to the second aspect of the present invention, the first one-way clutch is disposed in parallel with the first brake and can be engaged by the fourth brake, and the fifth clutch is disposed in parallel with the third brake. Since it has a second one-way clutch that can be freely engaged by the brake and a third one-way clutch that is disposed in parallel with the second brake, the shift performed by switching the first, second, and third brakes Is the first,
This can be performed by the second and third one-way clutches, and the shifts can be smoothly performed.

According to the third aspect of the present invention, the planetary gear unit has a pinion between the carrier and the second ring gear, and the pinion rotates lower than the rotation of the input portion. By configuring to achieve the first reverse speed, the durability of the bearings supporting the pinion and the like can be improved, and other members can also be reduced in deterioration over time to improve the durability. .

According to the fourth aspect of the present invention, since the plurality of frictional engagement elements are arranged in a concentrated manner on the input side of the planetary gear unit, the plurality of frictional engagement elements are divided and input from the planetary gear unit. And a plurality of friction engagement elements can be arranged in a large space without the planetary gear unit. Thereby,
When actually configuring the automatic transmission mechanism, the friction engagement elements can be provided without having a multiple structure. Further, since the friction engagement elements are not provided on the outer diameter side of the planetary gear unit, the size of the automatic transmission mechanism can be reduced in the radial direction.

According to the fifth aspect of the present invention, the first, second and third one-way clutches include the first, second, third and third one-way clutches.
Since it is arranged on the inner diameter side of the fourth and fifth brakes,
When actually configuring the automatic transmission mechanism, first,
The second and third one-way clutches are first, second, third,
An empty space in the inner diameter of the fourth and fifth brakes,
The automatic transmission mechanism can be arranged in a so-called dead space, and can have an efficient arrangement structure. Thereby, the automatic transmission mechanism can be made compact.

According to the sixth aspect of the present invention, since the carrier integrally forms the inner race of the third one-way clutch, the inner race of the third one-way clutch is actually formed when the automatic transmission mechanism is actually formed. Since the race can be integrally formed by forming the race integrally with, for example, a flange portion extended from the carrier, the need for welding another member is eliminated, and the need for welding another member is eliminated. The man-hours can be reduced, the number of parts can be reduced, and the cost of the automatic transmission mechanism can be reduced.

According to the seventh aspect of the present invention, since the first sun gear integrally forms the inner race of the first one-way clutch, when the automatic transmission mechanism is actually constructed, the first one-way clutch is formed. Since the inner race can be configured integrally with the first sun gear and used in common, it is possible to reduce the number of parts and the number of parts by eliminating the necessity of welding another member and the like, and the automatic transmission mechanism Cost can be reduced.

According to the present invention, since the first ring gear integrally forms the inner race of the second one-way clutch, the second one-way clutch is used when the automatic transmission mechanism is actually constructed. The inner race can be integrally formed with, for example, a hub portion extended from the first ring gear, so that the need for welding another member or the like can be eliminated, and the man-hour can be reduced. The number of parts can be reduced, and the cost of the automatic transmission mechanism can be reduced.

According to the ninth aspect of the present invention, the first one-way clutch is engaged at a relatively middle speed and regulates the rotation of the first ring gear in one direction. It can be relatively small. Thereby, when the present automatic transmission mechanism is actually configured, the first one-way clutch can be disposed, for example, in an empty space, and the third one-way clutch is disposed on the outer diameter of the first one-way clutch. Since a so-called double structure can be adopted, an efficient arrangement structure can be achieved, and the automatic transmission mechanism can be made compact.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, showing a skeleton diagram, a speed diagram, an operation table, and a gear ratio of an automatic transmission mechanism.

FIG. 2 is a view showing another embodiment of the present invention, showing a skeleton diagram, a speed diagram, an operation table, and a gear ratio of the automatic transmission mechanism.

FIG. 3 is a diagram showing a rotation speed ratio of a pinion to an input rotation speed in the automatic transmission mechanism shown in FIG. 2;

[Description of Signs] RP Planetary gear unit IN Input section OUT Output section S2 First sun gear S3 Second sun gear CR2 Carrier R2 First ring gear R3 Second ring gear P1 .. Long pinion P3 Pinion C-3 First clutch C-1 Second clutch C-2 Third clutch B-1 in FIG. 1, B-2 in FIG. 1 B-3, B-5 in FIG. 2... Second brake B-2 in FIG. 1, B-4 in FIG. 2... Third brake B-1 in FIG. -3: Fifth brake F-1: First one-way clutch F-2: Second one-way clutch F-3: Third one-way clutch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhisa Ozaki 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Inventor Yoichi Hayakawa 10 Takane, Fujii-machi, Anjo, Aichi Prefecture F term in NW Corporation (reference) 3J028 EA25 EA27 EB07 EB13 EB31 EB33 FB03 FC17 FC24 FC63 FD01 GA02

Claims (9)

[Claims] 1. A planetary gear unit having at least three tooth ratios via one long pinion, and a plurality of planetary gear units interposed between an input portion and an output portion, the transmission paths of which can be changed. A friction engagement element;
Wherein the plurality of friction engagement elements have a first clutch, a second clutch, a third clutch, a first brake, a second brake, and a third brake, and the planetary gear unit , The first input to the input unit
A first sun gear connected to the first brake while being connected via a clutch, a second sun gear connected to the input unit via the second clutch, and the third clutch connected to the input unit And the second
A carrier connected to a brake, a first ring gear connected to the third brake, and a second ring gear connected to the output portion; the first, second, third clutches and the first and second clutches; An automatic transmission mechanism wherein at least five forward speeds and one reverse speed are achieved by switching the third brake. 2. The friction engagement element includes a fourth brake, a fifth brake, a first one-way clutch disposed in parallel with the first brake, and capable of being engaged by the fourth brake. A second one-way clutch disposed in parallel with the third brake and capable of being engaged by the fifth brake; and a third one-way clutch disposed in parallel with the second brake. The automatic transmission mechanism according to claim 1. 3. The automatic transmission mechanism according to claim 2, wherein the planetary gear unit has a pinion between the carrier and the second ring gear, and the pinion rotates at a speed lower than a rotation of the input unit. . 4. The automatic transmission mechanism according to claim 2, wherein the plurality of friction engagement elements are arranged in a concentrated manner on an input side of the planetary gear unit. 5. The brake according to claim 2, wherein the first, second and third one-way clutches are disposed on inner diameter sides of the first, second, third, fourth and fifth brakes. The automatic transmission mechanism according to any one of the above. 6. The automatic transmission mechanism according to claim 2, wherein the carrier integrally forms an inner race of the third one-way clutch. 7. The automatic transmission mechanism according to claim 2, wherein the first sun gear integrally forms an inner race of the first one-way clutch. 8. The automatic transmission mechanism according to claim 2, wherein the first ring gear integrally forms an inner race of the second one-way clutch. 9. The automatic transmission mechanism according to claim 2, wherein the first one-way clutch is engaged at a relatively middle speed, and restricts rotation of the first ring gear in one direction. .