JP2017032036A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission capable of attaining multistage transmission without prolonging the entire length in an axial direction.SOLUTION: An automatic transmission includes a first counter shaft part 6 capable of transmitting rotation of a counter gear 35 to an input gear 81, and a second counter shaft part 7 capable of transmitting rotation of the counter gear 35 into the input gear 81. In the automatic transmission, a first transmission ratio that is a transmission ratio of a first power transmission route a1 in which rotation is transmitted from the counter gear 35 to an input gear 81 through the first counter shaft part 6, is different from a second transmission ratio that is a transmission ratio of a second power transmission route a2 in which rotation is transmitted from the counter gear 35 to the input gear 81 through the second counter shaft part 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an automatic transmission that is mounted on a vehicle such as an automobile and has a speed change mechanism.

  2. Description of the Related Art Conventionally, for example, in an automatic transmission suitable for use in a vehicle, a multi-speed transmission mechanism that can form, for example, a forward speed of eight or more forward speeds has been widely used. As an automatic transmission provided with such a multi-stage transmission mechanism, for example, an automatic transmission capable of forming 10 forward speed stages is known (see Patent Document 1). This automatic transmission includes four planetary gears and six engagement elements, and a combination of the engagement elements can form a forward 10th speed.

JP-A-2015-108387

  However, in the automatic transmission described in Patent Document 1, four planetary gears are arranged coaxially with the input shaft in the axial direction. For this reason, there existed a problem that the full length of the axial direction of an automatic transmission became long, and the mounting property to a vehicle fell.

  An object of the present invention is to provide an automatic transmission that can realize multi-speed shifting without increasing the overall length in the axial direction.

  An automatic transmission according to the present disclosure includes an input member that is drivingly connected to a drive source, a speed change mechanism that shifts the rotation of the input member and outputs the result from a counter gear, and an input gear, and is input to the input gear. A differential unit that outputs the rotation to the wheel, a first driven gear that meshes with the counter gear, a first drive gear that meshes with the input gear, the first driven gear, and the first drive gear A first countershaft that is capable of switching between a connected state and a disconnected state interposed between the first countershaft and the input gear. A first countershaft portion capable of transmitting to the second gear, a second driven gear meshing with the counter gear, a second drive gear meshing with the input gear, and the second drib A second countershaft that can connect the gear and the second drive gear, and a second engagement element that is interposed in the second countershaft and can be switched between a connected state and a disconnected state. A second countershaft portion capable of transmitting the rotation of the counter gear to the input gear, and the rotation is transmitted from the counter gear to the input gear via the first countershaft portion. A first transmission ratio, which is a transmission ratio of the power transmission path, and a transmission ratio of the second power transmission path, in which rotation is transmitted from the counter gear to the input gear via the second countershaft portion. This is different from the second gear ratio.

  According to this automatic transmission, since there are two power transmission paths having different speed ratios between the counter gear of the speed change mechanism and the input gear of the differential section, a range of two speed ratios is realized by one speed change mechanism. be able to. For this reason, since the range of the gear ratio of the automatic transmission can be expanded as compared with the case of having only one power transmission path, a multi-stage shift with a larger number of stages can be realized. Further, the first power transmission path and the second power transmission path are formed through the first counter shaft portion and the second counter shaft portion, and the first counter shaft portion and the second counter shaft portion. Need not be arranged coaxially with the counter gear of the speed change mechanism. As a result, multi-stage shifting can be realized without increasing the overall axial length of the automatic transmission.

The skeleton figure which shows the automatic transmission which concerns on embodiment. The engagement table of the automatic transmission which concerns on embodiment. The front view which shows arrangement | positioning of each axis | shaft of the automatic transmission which concerns on embodiment. The engagement table which the automatic transmission which concerns on embodiment deform | transformed.

  Hereinafter, an embodiment of a vehicle drive device will be described with reference to FIGS. 1 to 3.

  The automatic transmission according to the present embodiment is suitable for mounting on, for example, an FF (front engine / front drive) type vehicle, and the left-right direction in FIG. 1 is the left-right direction (or left-right) in the actual vehicle-mounted state. Corresponding to the reverse direction).

  In addition, the drive connection refers to a state in which the rotating elements are connected so as to be able to transmit the driving force, and the rotating elements are connected so as to rotate integrally, or the rotating elements are connected via a clutch or the like. Thus, it is used as a concept including a state where the driving force is connected so as to be transmitted. In the present embodiment, the speed change mechanism 31 is set to the eighth forward speed, but is not limited thereto, and may be a stepped transmission that achieves the third to seventh forward speeds, or the belt. A continuously variable transmission mechanism such as a continuously variable transmission, a toroidal continuously variable transmission, or a cone ring continuously variable transmission may be used, that is, any transmission mechanism may be applied.

  A schematic configuration of a vehicle 1 including the automatic transmission 3 according to the present embodiment will be described with reference to FIG. The vehicle 1 includes an internal combustion engine (drive source) 2, an automatic transmission 3, front wheels (wheels) 4, and an ECU 5. The internal combustion engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine, and is connected to the automatic transmission 3.

  The automatic transmission 3 includes an input shaft (input member) 30, a starting device 10, a speed change mechanism 31, a first counter shaft portion 6, a second counter shaft portion 7, a differential portion 8, and A case 32 to be accommodated and a hydraulic control device 33 are provided. The input shaft 30 of the automatic transmission 3 is disposed on the first shaft AX1 and is drivingly connected to the crankshaft 20 of the internal combustion engine 2.

  The starting device 10 includes a torque converter 11 and a lockup clutch 12 that can lock it up. The torque converter 11 is disposed between a pump impeller 11a connected to the input shaft 30 of the automatic transmission 3, a turbine runner 11b to which rotation of the pump impeller 11a is transmitted via oil as a working fluid. And a stator 11c whose rotation is restricted in one direction by a one-way clutch 11d. The turbine runner 11 b is connected to an input shaft 34 of a transmission mechanism 31 that is coaxial with the input shaft 30. The lock-up clutch 12 directly engages the front cover 12a and the input shaft 34 of the speed change mechanism 31 by engagement, and brings the torque converter 11 into a locked-up state.

  The speed change mechanism 31 includes a planetary gear DP and a speed change planetary gear unit PU on the input shaft 34. The planetary gear DP includes a first sun gear S1, a first carrier CR1, and a first ring gear R1, and the pinion P2 and the first ring gear R1 meshing with the first sun gear S1 are engaged with the first carrier CR1. This is a so-called double pinion planetary gear having pinions P1 meshing with each other.

  On the other hand, the planetary gear unit PU has a second sun gear S2, a third sun gear S3, a second carrier CR2, and a second ring gear R2 as four rotating elements, and the second carrier CR2 includes a third sun gear. This is a so-called Ravigneaux type planetary gear having a long pinion P3 meshing with S3 and the second ring gear R2 and a short pinion P4 meshing with the second sun gear S2.

  The rotation of the first sun gear S <b> 1 of the planetary gear DP is fixed with respect to the case 32. Further, the first carrier CR1 is connected to the input shaft 34, is rotated in the same rotation as the rotation of the input shaft 34 (hereinafter referred to as input rotation), and is connected to the fourth clutch C4. Further, the first ring gear R1 is decelerated by the input rotation being decelerated by the fixed first sun gear S1 and the first carrier CR1 that rotates, and the first clutch C1 and the third clutch It is connected to the clutch C3.

  The third sun gear S3 of the planetary gear unit PU is connected to the first brake B1 and can be fixed to the case 32, and is connected to the fourth clutch C4 and the third clutch C3. The input rotation of the first carrier CR1 can be input via the fourth clutch C4, and the decelerated rotation of the first ring gear R1 can be input via the third clutch C3. Further, the second sun gear S2 is connected to the first clutch C1, and the reduced rotation of the first ring gear R1 can be input.

  Further, the second carrier CR2 is connected to the second clutch C2 to which the rotation of the input shaft 34 is input, and the input rotation can be freely input via the second clutch C2. The carrier CR2 is connected to the second brake B2 and the one-way clutch (OWC) F1, and the rotation can be fixed via the second brake B2 or the one-way clutch F1. The second ring gear R <b> 2 is connected to a counter gear 35 that is rotatably supported with respect to a center support member fixed to the case 32. That is, the speed change mechanism 31 shifts the rotation of the input shaft 34 and outputs it from the counter gear 35. The counter gear 35 is disposed on the first axis AX1 and is connected to the differential portion 8 by one of the first counter shaft portion 6 and the second counter shaft portion 7.

  Here, the speed change mechanism 31 configured as described above, with respect to the output from the counter gear 35, the first clutch C1 to the fourth clutch C4, the first brake B1 and the first brake B1 shown in the skeleton diagram of FIG. 2 is engaged and disengaged in the combinations shown in the engagement table of FIG. 2 except for the counter clutch, so that the first forward speed (1st) to the eighth forward speed (8th) and the first reverse speed (Rev1) ) To 2nd reverse speed (Rev2) are achieved.

  The differential unit 8 includes a differential gear 80 and an input gear 81. The differential gear 80 is connected to axles 82 of the left and right front wheels 4. Thereby, the differential unit 8 outputs the rotation input to the input gear 81 to the front wheel 4 via the differential gear 80. The input gear 81 is disposed on a second axis AX2 that is parallel to the first axis AX1. Further, as shown in FIG. 3, the first axis AX1 and the second axis AX2 are arranged side by side in a substantially horizontal direction.

  As shown in FIG. 1, the first counter shaft portion 6 includes a first driven gear 60, a first drive gear 61, a first counter shaft 62, and a low-side counter clutch (first engaging element). ) 63 and the rotation of the counter gear 35 can be transmitted to the input gear 81 of the differential section 8. The first driven gear 60 is meshed with the counter gear 35. The first drive gear 61 is engaged with the input gear 81. The low-side counter clutch 63 is, for example, a friction engagement element having a single or a plurality of friction plates, and can be switched between a connected state and a disconnected state via the first counter shaft 62. The first countershaft 62 can connect the first driven gear 60 and the first drive gear 61 by interposing the low-side counter clutch 63. The first countershaft portion 6 is disposed on a third axis AX3 that is parallel to the second axis AX2. The first countershaft portion 6 is disposed in parallel with the first axis AX1 and does not increase the overall length of the automatic transmission 3 in the axial direction.

  The number of teeth of the first drive gear 61 is less than the number of teeth of the first driven gear 60, and the rotation of the counter gear 35 is decelerated by the first counter shaft portion 6. A power transmission path through which rotation is transmitted from the counter gear 35 to the input gear 81 via the first counter shaft portion 6 is referred to as a first power transmission path a1. Further, the speed ratio of the first power transmission path a1 is defined as a first speed ratio. Further, as shown in FIG. 3, when viewed from the axial direction, a straight line connecting the first axis AX1 and the second axis AX2 is defined as a boundary BO, and the third axis AX3 is disposed above the boundary BO.

  As shown in FIG. 1, the second countershaft portion 7 includes a second driven gear 70, a second drive gear 71, a second countershaft 72, and a high-side counter clutch (second engagement element). 73) and the rotation of the counter gear 35 can be transmitted to the input gear 81 of the differential section 8. The second driven gear 70 meshes with the counter gear 35. The second drive gear 71 is meshed with the input gear 81. The high-side counter clutch 73 is a friction engagement element having one or a plurality of friction plates, for example, and can be switched between a connected state and a disconnected state by being interposed by the second counter shaft 72. The second countershaft 72 can connect the second driven gear 70 and the second drive gear 71 by interposing a high counter clutch 73. The second countershaft portion 7 is disposed on a fourth axis AX4 that is parallel to the third axis AX3. The second countershaft portion 7 is arranged in parallel with the first axis AX1, and does not increase the overall length of the automatic transmission 3 in the axial direction.

  The number of teeth of the second drive gear 71 is less than the number of teeth of the second driven gear 70, and the rotation of the counter gear 35 is decelerated by the second counter shaft portion 7. A power transmission path through which rotation is transmitted from the counter gear 35 to the input gear 81 via the second counter shaft portion 7 is referred to as a second power transmission path a2. Further, the speed ratio of the second power transmission path a2 is defined as a second speed ratio. Further, as shown in FIG. 3, when viewed from the axial direction, a straight line connecting the first axis AX1 and the second axis AX2 is defined as a boundary BO, and the fourth axis AX4 is disposed below the boundary BO.

  Here, as shown in FIG. 1, the first speed ratio of the first power transmission path a1 through the first countershaft portion 6 and the second power transmission path a2 through the second countershaft portion 7. This is different from the second gear ratio. In the present embodiment, the second driven gear 70 has a smaller diameter than the first driven gear 60, and the second gear ratio is set smaller than the first gear ratio. That is, the gear ratio between the second driven gear 70 and the second drive gear 71 is set smaller than the gear ratio between the first driven gear 60 and the first drive gear 61. For this reason, the low-side counter clutch 63 forms a low-speed (Low) gear position when connected, and the high-side counter clutch 73 forms a high-speed (High) gear position when connected.

  In the present embodiment, the transmission gear ratio of the eighth forward speed when the first countershaft portion 6 is connected is larger than the gear ratio of the first forward speed when the second countershaft portion 7 is connected. In addition, a first gear ratio and a second gear ratio are set. As a result, as shown in FIG. 2, when the low-side counter clutch 63 is connected, the automatic transmission 3 operates in the first forward speed (1st) to the eighth forward speed (8th), and the first reverse speed (Rev1) to reverse. When the second speed (Rev2) is achieved and the high-side counter clutch 73 is connected, the automatic transmission 3 operates in the ninth forward speed (9th) to the sixteenth forward speed (16th) and the third reverse speed (Rev3) to the reverse speed. Fourth speed (Rev4) is achieved. Note that the ECU 5 selectively engages / disengages either the low-side counter clutch 63 or the high-side counter clutch 73.

  The automatic transmission 3 configured as described above includes the first clutch C1 to the fourth clutch C4, the first brake B1 and the second brake B2, and the low-side counter clutch 63 shown in the skeleton diagram of FIG. And the high-side counter clutch 73 are engaged and disengaged in the combinations shown in the engagement table of FIG. 2, so that the forward first speed (1st) to the forward 16th speed (16th) and the reverse first speed (Rev1) to The fourth reverse speed (Rev4) is achieved.

  The hydraulic control device 33 is configured by, for example, a valve body, generates line pressure or the like from the hydraulic pressure supplied from the oil pump, and each of the first to fourth clutches C1 to C4 based on a control signal from the ECU 5; The hydraulic pressure for controlling the first and second brakes B1 and B2, and the low-side counter clutch 63 and the high-side counter clutch 73 can be supplied and discharged.

  The ECU 5 includes, for example, a CPU, a ROM that stores processing programs, a RAM that temporarily stores data, an input / output port, and a communication port. The ECU 5 sets, for example, the gear position of the automatic transmission 3 in accordance with the vehicle speed, the amount of depression of an accelerator pedal (not shown), and the like, and forms each of the first to fourth clutches C1, for example. ~ C4, the first and second brakes B1 and B2, and the low-side counter clutch 63 and the high-side counter clutch 73 are output with control signals.

  The operation of the automatic transmission 3 described above will be described below.

  As shown in FIG. 1, when the vehicle 1 starts and travels at a low speed, the ECU 5 connects the low counter clutch 63 and disconnects the high counter clutch 73. Thereby, as shown in FIG. 2, the automatic transmission 3 can form the first forward speed to the eighth forward speed, and can select a low-speed gear stage suitable for low-speed traveling.

  As shown in FIG. 1, when the vehicle 1 accelerates and travels forward at a high speed, the ECU 5 disconnects the Low-side counter clutch 63 and connects the High-side counter clutch 73. Thereby, as shown in FIG. 2, the automatic transmission 3 can form the 9th forward speed to the 16th forward speed, and can select a high-speed gear stage suitable for high-speed travel.

  Similarly, when the vehicle 1 travels backward, the low-side counter clutch 63 is connected during low-speed traveling and the high-side counter clutch 73 is disconnected, so that the reverse 1st speed to the reverse 2nd speed suitable for low-speed travel are achieved. When the vehicle is traveling at a high speed, the low-side counter clutch 63 is disconnected and the high-side counter clutch 73 is connected to form a reverse third gear to a reverse fourth gear suitable for high-speed travel.

  As described above, according to the automatic transmission 3 of the present embodiment, there are two power transmission paths a1 and a2 having different speed ratios between the counter gear 35 and the input gear 81, so one speed change mechanism. 31 can realize two speed ratio ranges. For this reason, since the range of the gear ratio of the automatic transmission 3 can be expanded compared with the case where only one power transmission path is provided, a multi-stage shift with a larger number of stages can be realized. The first power transmission path a1 and the second power transmission path a2 are formed via the first counter shaft portion 6 and the second counter shaft portion 7, and the first counter shaft portion 6 and the second power transmission route a2 are formed. The second counter shaft portion 7 is disposed on a different axis from the counter gear 35 and the input gear 81. Thereby, it is possible to realize a multi-speed shift without increasing the overall axial length of the automatic transmission 3.

  In addition, by using an existing configuration as the speed change mechanism 31, the automatic transmission 3 according to the present embodiment can be realized only by adding one countershaft portion, thereby suppressing a significant increase in manufacturing cost. be able to.

  Further, according to the automatic transmission 3 of the present embodiment, as shown in FIG. 3, the second driven gear 70 has a smaller diameter than the first driven gear 60, and the second countershaft portion is viewed from the axial direction. 7 is arranged below the boundary BO. For this reason, compared with the case where the 1st countershaft part 6 is arrange | positioned under the boundary BO, the enlargement of the lower part of the automatic transmission 3 is suppressed, and the mounting property to the vehicle 1 of the automatic transmission 3 is improved. At the same time, the ground clearance can be kept high.

  In the above-described embodiment, as shown in FIG. 2, when the low-side counter clutch 63 is connected, the automatic transmission 3 moves from the first forward speed (1st) to the eighth forward speed (8th) and reverse. 1st speed (Rev1) to 2nd reverse speed (Rev2) is achieved, and when the high-side counter clutch 73 is connected, the automatic transmission 3 moves forward 9th speed (9th) to 16th forward speed (16th) and reverse Although the case where the third speed (Rev3) to the fourth reverse speed (Rev4) is achieved has been described, the present invention is not limited to this. For example, the low-side counter clutch 63 is configured such that the transmission ratio of the automatic transmission 3 when the low-side counter clutch 63 is connected and the transmission ratio of the automatic transmission 3 when the high-side counter clutch 73 is connected are partially overlapped. Alternatively, the shift stage of the automatic transmission 3 at the time of connection of the high-speed counter 3 and the shift stage of the automatic transmission 3 at the time of connection of the high-side counter clutch 73 may be alternately formed.

  Further, in the present embodiment described above, a case has been described in which the automatic transmission 3 with 16 forward speeds using the transmission mechanism 31 with 8 forward speeds is used, but the present invention is not limited thereto. For example, as shown in FIG. 4, when the Low-side counter clutch 63 is connected, all the speeds (first forward speed to eighth forward speed) of the speed change mechanism 31 are used, and when the High side counter clutch 73 is connected, the speed change mechanism 31 is used. The automatic transmission 3 may be configured to be capable of forming a forward 10-speed stage as a whole using the high-speed stage side (forward 7-speed to forward 8-speed). In this case, the difference in diameter between the counter gear 35 and the first driven gear 60 and the second driven gear 70 can be made relatively small, so that the mountability of the automatic transmission 3 on the vehicle 1 can be further improved. Alternatively, for example, the low speed side of the speed change mechanism 31 (for example, the first forward speed to the seventh forward speed) is used when the low counter clutch 63 is connected, and the high speed stage of the speed change mechanism 31 is connected when the high counter clutch 73 is connected. The automatic transmission 3 that can form the forward 10th speed and other speed stages as a whole by using the side (for example, the 6th forward speed to the 8th forward speed) may be used. Or it is not restricted to using the transmission mechanism 31 of the forward 8 speed stage, For example, you may make it form the gear stage below the 12th forward speed stage using the transmission mechanism of the 6 forward speed stage.

  Similarly, as shown in FIG. 4, for example, as shown in FIG. 4, the low speed side reverse speed when the low counter clutch 63 is connected is set to 1st low, and the high speed side reverse speed when the low counter clutch 63 is connected. May be set to 2nd low so that the second reverse speed is achieved. Alternatively, for example, when the low counter clutch 63 is connected, the low speed reverse gear is super low, when the low counter clutch 63 is connected, the high speed reverse gear is 1st low, and when the high counter clutch 73 is connected. The reverse speed of the low speed side may be 2nd low.

  In the above-described embodiment, the case where the friction engagement element having one or a plurality of friction plates is applied as the low-side counter clutch 63 and the high-side counter clutch 73 has been described. Absent. As the low-side counter clutch 63 and the high-side counter clutch 73, for example, a dog clutch or a two-way clutch can be applied.

  In the above-described embodiment, the case where a multi-stage transmission mechanism capable of forming a plurality of shift stages by applying a combination of engagement / disengagement of a plurality of engagement elements is applied as the transmission mechanism 31 is described. I can't. As the transmission mechanism, for example, a continuously variable transmission mechanism such as a belt-type continuously variable transmission, a toroidal continuously variable transmission, or a cone ring continuously variable transmission may be applied. In this case, the first countershaft portion 6 and the second countershaft portion 7 are selectively connected to one continuously variable transmission mechanism, so that the range of two gear ratios can be reduced by one continuously variable transmission mechanism. Can be realized. For this reason, the range of the gear ratio of the automatic transmission 3 can be expanded compared with the case where only one power transmission path is provided. Further, since the first countershaft portion 6 and the second countershaft portion 7 do not need to be arranged coaxially with the two axes of the continuously variable transmission mechanism, the overall length of the automatic transmission 3 in the axial direction is increased. There is no.

  The present embodiment includes at least the following configuration. The automatic transmission (3) of the present embodiment shifts the rotation of the input member (30) that is drivingly connected to the drive source (2) and the input member (30), and outputs it from the counter gear (35). A differential mechanism (8) having a speed change mechanism (31) and an input gear (81) and outputting rotation input to the input gear (81) to a wheel (4), and meshing with the counter gear (35) The first driven gear (60), the first drive gear (61) meshing with the input gear (81), the first driven gear (60) and the first drive gear (61) can be connected. A first countershaft (62), and a first engagement element (63) interposed between the first countershaft (62) and switchable between a connected state and a disconnected state, The rotation of the counter gear (35) A first countershaft portion (6) capable of transmitting to the gear (81), a second driven gear (70) meshing with the counter gear (35), and a second drive meshing with the input gear (81) A gear (71), a second counter shaft (72) capable of connecting the second driven gear (70) and the second drive gear (71), and the second counter shaft (72) are interposed. A second engagement shaft (73) that can be switched between a connected state and a disconnected state, and capable of transmitting the rotation of the counter gear (35) to the input gear (81). And a first power transmission path (a1) through which rotation is transmitted from the counter gear (35) to the input gear (81) via the first counter shaft portion (6). Is the first gear ratio The transmission gear ratio and the transmission gear ratio of the second power transmission path (a2) through which rotation is transmitted from the counter gear (35) to the input gear (81) via the second counter shaft portion (7). This is different from the second gear ratio. According to this configuration, the two power transmission paths (a1, a2) having different speed ratios are provided between the counter gear (35) of the transmission mechanism (31) and the input gear (81) of the differential section (8). Therefore, two speed ratio ranges can be realized by one speed change mechanism (31). For this reason, since the range of the gear ratio of the automatic transmission (3) can be expanded as compared with the case of having only one power transmission path, a multi-stage shift with a larger number of stages can be realized. The first power transmission path (a1) and the second power transmission path (a2) are formed through the first countershaft portion (6) and the second countershaft portion (7). The first countershaft portion (6) and the second countershaft portion (7) need not be arranged coaxially with the counter gear (35) of the transmission mechanism (31). Thereby, it is possible to realize a multi-stage shift without increasing the overall axial length of the automatic transmission (3).

  In the automatic transmission (3) of the present embodiment, the counter gear (35) is disposed on the first shaft (AX1), and the input gear (81) is disposed on the first shaft (AX1). The first counter shaft portion (6) is disposed on a second axis (AX2) parallel to the second axis (AX2), and the second counter shaft (AX2) is parallel to the second axis (AX2). The counter shaft portion (7) is disposed on a fourth axis (AX4) parallel to the third axis (AX3). According to this configuration, the first counter shaft portion (6) and the second counter shaft portion (7) are both arranged on different axes from the counter gear (35) and the input gear (81). For this reason, multi-stage gear shifting can be realized without increasing the overall axial length of the automatic transmission (3).

  In the automatic transmission (3) of the present embodiment, the second driven gear (70) has a smaller diameter than the first driven gear (60), and the second speed change ratio is the first speed change. The straight line connecting the first axis (AX1) and the second axis (AX2) when viewed from the axial direction is a boundary (BO), and the third axis (AX3) is the boundary of the boundary (BO). Arranged on the upper side, the fourth axis (AX4) is arranged below the boundary (BO). According to this configuration, the second countershaft portion (7) having the second driven gear (70) having a smaller diameter than the first driven gear (60) is disposed below the boundary (BO). Compared to the case where the countershaft portion (6) of the automatic transmission (3) is arranged below the boundary (BO), the size of the lower portion of the automatic transmission (3) is suppressed, and the automatic transmission (3) to the vehicle (1) is suppressed. Mountability can be improved and the minimum ground clearance can be maintained high.

1 Vehicle 2 Internal combustion engine (drive source)
3 Automatic transmission 4 Front wheels
6 First counter shaft portion 7 Second counter shaft portion 8 Differential portion 30 Input shaft (input member)
31 Transmission mechanism 35 Counter gear 60 First driven gear 61 First drive gear 62 First counter shaft 63 Low counter clutch (first engagement element)
70 Second driven gear 71 Second drive gear 72 Second counter shaft 73 High counter clutch (second engagement element)
81 Input gear AX1 First axis AX2 Second axis AX3 Third axis AX4 Fourth axis a1 First power transmission path a2 Second power transmission path BO Boundary

Claims (3)

An input member drivingly coupled to the drive source;
A speed change mechanism that changes the rotation of the input member and outputs it from the counter gear;
A differential unit that has an input gear and outputs the rotation input to the input gear to a wheel;
A first driven gear meshing with the counter gear; a first drive gear meshing with the input gear; a first counter shaft capable of connecting the first driven gear and the first drive gear; A first engaging shaft that is interposed in one countershaft and is switchable between a connected state and a disconnected state, and capable of transmitting the rotation of the counter gear to the input gear; ,
A second driven gear meshing with the counter gear; a second drive gear meshing with the input gear; a second counter shaft capable of connecting the second driven gear and the second drive gear; A second engagement element interposed between the two countershafts and capable of switching between a connected state and a disconnected state; and a second countershaft portion capable of transmitting the rotation of the counter gear to the input gear. With
A first gear ratio which is a gear ratio of a first power transmission path through which rotation is transmitted from the counter gear to the input gear via the first counter shaft portion; and from the counter gear to the second counter An automatic transmission that is different from a second speed ratio that is a speed ratio of a second power transmission path through which rotation is transmitted to the input gear via a shaft portion. The counter gear is disposed on a first shaft;
The input gear is disposed on a second axis parallel to the first axis;
The first countershaft portion is disposed on a third axis parallel to the second axis;
The automatic transmission according to claim 1, wherein the second countershaft portion is disposed on a fourth axis parallel to the third axis. The second driven gear has a smaller diameter than the first driven gear, and the second speed ratio is smaller than the first speed ratio,
Viewed from the axial direction, with the straight line connecting the first axis and the second axis as a boundary, the third axis is disposed above the boundary, and the fourth axis is disposed below the boundary. The automatic transmission according to claim 2.

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