JP2018001880A - Speed change unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed change unit which can increase the transmission torque capacity of a lock-up mechanism while inhibiting deterioration of fuel economy and extension of an entire unit lenth.SOLUTION: A torque converter 2 includes: a front cover 11; a pump impeller 12; a turbine runner 14; and a lock-up mechanism 15. An automatic transmission includes an input shaft 41 and an output shaft 42. The input shaft 41 and the output shaft 42 are arranged parallel to each other while spaced away from each other. A part of a torus part 101, in which the pump impeller 12 and the turbine runner 14 are disposed, overlaps with an engine side end part 104 of the output shaft 42 in a rotation radial direction. A part of a clutch damper part 102, in which the lock-up mechanism 15 is disposed, overlaps with the output shaft 42 in a rotation axial direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a transmission unit including a torque converter and an automatic transmission.

  In a vehicle equipped with an automatic transmission, the torque generated by the engine is input to the automatic transmission via a torque converter, and the driving force changed by the automatic transmission is transmitted to the drive wheels. For example, a continuously variable transmission (CVT) or a stepped automatic transmission (AT) is widely used as the automatic transmission.

  The torque converter includes a front cover, a pump impeller, and a turbine runner. The front cover and the pump impeller are fixed to each other to form a space therebetween. The front cover is disposed on the engine side with respect to the pump impeller. The turbine runner is accommodated in a space between the front cover and the pump impeller, and is provided to be rotatable relative to the front cover and the pump impeller about the same rotational axis.

  The driving force from the engine is input to the front cover. The front cover and the pump impeller rotate integrally by the input driving force. When the pump impeller rotates, oil flows from the pump impeller toward the turbine runner. This oil flow is received by the turbine runner, and the turbine runner rotates. At this time, a torque amplification effect occurs. An input shaft of an automatic transmission is connected to the turbine runner so as not to be relatively rotatable. When the turbine runner rotates, the input shaft of the automatic transmission rotates together with the turbine runner, whereby the driving force is transmitted from the torque converter to the automatic transmission.

  Further, the torque converter incorporates a lockup mechanism for directly connecting the pump impeller and the turbine runner. The lockup mechanism includes a lockup piston (lockup clutch) disposed between the front cover and the turbine runner. A friction material is adhered to a surface of the lockup piston facing the front cover. When the lock-up piston moves to the front cover side due to the hydraulic pressure and the friction material is pressed against the inner surface of the front cover, the pump impeller and the turbine runner are directly connected to each other, and the driving force from the engine is automatically transmitted. Communicated directly to.

  The automatic transmission includes an input shaft, an output shaft, and a transmission mechanism. The input shaft and the output shaft are parallel to each other with a space therebetween. The transmission mechanism shifts the rotation of the input shaft and transmits it to the output shaft. The driving force input from the torque converter to the input shaft is transmitted to the output shaft through the speed change mechanism, and is transmitted from the output shaft to the left and right drive wheels through the differential gear.

Japanese Patent Laying-Open No. 2015-145682

  The torque converter lockup mechanism requires a transmission torque capacity capable of transmitting the maximum torque output from the engine. Therefore, when the maximum torque of the engine is increased, it is necessary to increase the transmission torque capacity of the lockup mechanism. The transmission torque capacity of the lockup mechanism can be increased by increasing the hydraulic pressure (lockup hydraulic pressure) acting on the lockup piston in the lockup state or by increasing the radial size (torque diameter) of the torque converter.

  However, an increase in the lock-up hydraulic pressure causes an increase in engine load due to the oil pump that generates the hydraulic pressure, thereby deteriorating the fuel consumption of the vehicle. On the other hand, in order to increase the torque converter diameter, the position of the torque converter must be shifted axially with respect to the end of the output shaft in order to avoid interference between the torque converter and the output shaft of the automatic transmission. There is a concern that the axial total length (unit total length) of the transmission unit including the torque converter and the automatic transmission may increase. Therefore, a device is required to increase the transmission torque capacity of the lockup mechanism.

  An object of the present invention is to provide a transmission unit capable of increasing the transmission torque capacity of a lockup mechanism while suppressing deterioration of fuel consumption and expansion of the entire unit length.

  In order to achieve the above object, a transmission unit according to the present invention is a transmission unit including a torque converter and an automatic transmission, and the torque converter includes a front cover to which driving force from an engine is input, and a front cover. A pump impeller which is provided on the opposite side to the engine side and fixed to the front cover and forms a space between the front cover, and a turbine runner housed in a space between the front cover and the pump impeller; A first shaft that is provided between the front cover and the turbine runner and includes a lockup mechanism that directly couples / separates the front cover and the turbine runner by hydraulic pressure. And a second shaft provided parallel to the first shaft at a distance from each other, the pump in the torque converter A clutch damper portion in which at least a part of the torus portion where the impeller and the turbine runner are arranged overlaps with the end portion on the engine side of the second shaft in the radial direction of the second shaft, and a lockup mechanism in the torque converter is arranged A part of overlaps with the second axis in the axial direction of the second axis.

  According to this configuration, the torque converter includes the front cover, the pump impeller, the turbine runner, and the lockup mechanism. The pump impeller is disposed on the side opposite to the engine side with respect to the front cover. The turbine runner is accommodated in a space between the front cover and the pump impeller. The lockup mechanism is disposed between the turbine runner and the front cover. The automatic transmission includes a first shaft and a second shaft. The first shaft is an input shaft connected to the turbine runner so as not to rotate relative to the turbine runner. The second axis is parallel to the first axis at an interval.

  Then, at least a part of the torus portion where the pump impeller and the turbine runner are arranged overlaps (opposes) the radial direction of the second shaft with respect to the end portion of the second shaft on the engine side. Thereby, the axial length of the transmission unit (unit overall length) can be shortened as compared with the configuration in which the torque converter is disposed with the position completely shifted in the axial direction with respect to the second shaft.

  In addition, a part of the clutch damper portion where the lockup mechanism is disposed overlaps the second shaft in the axial direction. As a result, the radial size of the lockup mechanism can be increased while avoiding interference between the torque converter and the second shaft. By increasing the radial size of the lockup mechanism, the transmission torque capacity of the lockup mechanism can be increased without increasing the lockup hydraulic pressure (hydraulic pressure acting on the lockup piston in the lockup state).

  Therefore, it is possible to increase the transmission torque capacity of the lockup mechanism while suppressing deterioration of fuel consumption and expansion of the entire unit length.

  The lockup mechanism may be provided with a damper mechanism for attenuating vibration from the engine when the pump impeller and the turbine runner are directly connected.

  With this configuration, the radial size of the damper mechanism can be increased while avoiding interference between the torque converter and the second shaft. Since the size of the damper mechanism in the radial direction can be increased, the stopper torque of the damper mechanism can be increased, and vibration input to the torque converter can be effectively damped by the damper mechanism.

  According to the present invention, it is possible to increase the transmission torque capacity of the lockup mechanism while suppressing deterioration of fuel consumption and expansion of the entire unit length.

It is sectional drawing which shows the structure of the transmission unit which concerns on one Embodiment of this invention. It is a figure which shows the state of the engagement element contained in a power division type continuously variable transmission. FIG. 5 is a collinear diagram showing a relationship among rotation speeds (rotational speeds) of a sun gear, a carrier and a ring gear of a planetary gear mechanism included in a power split continuously variable transmission. It is sectional drawing which shows the positional relationship of a torque converter and the output shaft of a power division type continuously variable transmission.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Transmission unit>
FIG. 1 is a cross-sectional view showing a configuration of a transmission unit 1 according to an embodiment of the present invention. In FIG. 1, the hatching indicating the cross section is omitted.

  The transmission unit 1 is a unit that is mounted on a vehicle and that shifts torque generated by an engine (not shown) and transmits the torque to drive wheels (not shown). The torque converter 2 and the power split type continuously variable transmission 3 is included. The torque converter 2 and the power split type continuously variable transmission 3 are accommodated in a unit case 4 that forms an outer shell of the transmission unit 1.

<Torque converter>
The torque converter 2 includes a front cover 11, a pump impeller 12, a turbine hub 13, a turbine runner 14, a lockup mechanism 15, and a stator 16.

  The front cover 11 extends in a substantially disc shape around the rotation axis, and has an outer peripheral end bent toward the power split type continuously variable transmission 3 side. The center portion of the front cover 11 bulges toward the engine side. The generated torque (engine torque) of the engine is input to the bulged portion.

  The pump impeller 12 is disposed on the power split type continuously variable transmission 3 side of the front cover 11. The outer peripheral end of the pump impeller 12 is connected to the outer peripheral end of the front cover 11 and is provided so as to be able to rotate integrally with the front cover 11 around the rotation axis. A plurality of blades 17 are arranged radially on the inner surface of the pump impeller 12.

  The turbine hub 13 is disposed between the front cover 11 and the pump impeller 12.

  The turbine runner 14 is fixed to the turbine hub 13. A plurality of blades 18 are arranged radially on the surface of the turbine runner 14 facing the pump impeller 12.

  The lockup mechanism 15 includes a lockup piston 21 and a damper mechanism 22.

  The lockup piston 21 has a substantially annular plate shape, and an inner peripheral end portion thereof is externally fitted to the turbine hub 13 and is positioned between the front cover 11 and the turbine runner 14. If the hydraulic pressure of the engagement side oil chamber 23 on the turbine runner 14 side is higher than the hydraulic pressure of the release side oil chamber 24 on the front cover 11 side with respect to the lockup piston 21, the differential pressure causes the lockup piston 21 to move to the front cover. Move to the 11 side. When the lock-up piston 21 is pressed against the front cover 11, the pump impeller 12 and the turbine runner 14 are directly connected (lock-up on). Conversely, if the hydraulic pressure in the release side oil chamber 24 is higher than the hydraulic pressure in the engagement side oil chamber 23, the lockup piston 21 moves to the turbine runner 14 side due to the differential pressure. When the lock-up piston 21 is separated from the front cover 11, the direct connection between the pump impeller 12 and the turbine runner 14 is released (lock-up off).

  The damper mechanism 22 is a mechanism for dampening vibrations from the engine when the pump impeller 12 and the turbine runner 14 are directly connected. Specifically, the damper mechanism 22 is elastic to the retaining plate 25 supported by the lock-up piston 21, the spring 26 supported by the retaining plate 25, and the retaining plate 25 in the rotational direction via the spring 26. And a driven plate 27 connected to each other and an outer peripheral member 28 surrounding the outer periphery of the spring 26. The vibration input to the front cover 11 is damped by the spring 26 repeatedly compressing and restoring between the retaining plate 25 and the driven plate 27.

  The stator 16 is disposed between the pump impeller 12 and the turbine runner 14.

  When the pump impeller 12 is rotated by the engine torque in the lock-up off state, an oil flow from the pump impeller 12 toward the turbine runner 14 is generated. The oil flow is received by the blade 18 of the turbine runner 14 and the turbine runner 14 rotates. At this time, the amplifying action of the torque converter 2 occurs, and the turbine runner 14 generates torque larger than the engine torque.

<Power split type continuously variable transmission>
The power split type continuously variable transmission 3 transmits the power input from the torque converter 2 to the differential gear 6. The power split type continuously variable transmission 3 includes an input shaft 41, an output shaft 42, a continuously variable transmission mechanism 43, a reverse gear mechanism 44, a planetary gear mechanism 45, a split drive gear 46 and a split driven gear 47.

  The input shaft 41 is formed as a hollow shaft. The input shaft 41 extends on the rotational axis of the torque converter 2 and is inserted through the torque converter 2. The turbine hub 13 is splined to the end of the input shaft 41 on the engine side. As a result, the input shaft 41 rotates integrally with the turbine hub 13, and further rotates integrally with the turbine runner 14 and the lockup mechanism 15 fixed to the turbine hub 13.

  An oil pump 5 is disposed on the side opposite to the engine side with respect to the input shaft 41.

  The output shaft 42 is provided in parallel with the input shaft 41. An output gear 48 is formed integrally with the output shaft 42. The output gear 48 meshes with the differential gear 6 (the input gear of the differential gear 6).

  The continuously variable transmission mechanism 43 has the same configuration as a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 43 includes a primary shaft 51, a secondary shaft 52 provided in parallel with the primary shaft 51, a primary pulley 53 supported by the primary shaft 51 so as not to be relatively rotatable, and a secondary shaft 52. And a secondary pulley 54 supported so as not to rotate relative thereto, and a primary pulley 53 and a belt 55 wound around the secondary pulley 54.

  The primary pulley 53 is disposed so as to face the fixed sheave 61 fixed to the primary shaft 51 with the belt 55 sandwiched between the fixed sheave 61 and is supported by the primary shaft 51 so as to be movable in the axial direction but not to be relatively rotatable. (Primary sheave) 62. A cylinder 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 from the fixed sheave 61, and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the cylinder 63. Yes.

  The secondary pulley 54 is arranged so as to be opposed to the fixed sheave 65 fixed to the secondary shaft 52 with the belt 55 sandwiched between the fixed sheave 65 and supported on the secondary shaft 52 so as to be movable in the axial direction but not to be relatively rotatable. (Secondary sheave) 66. A cylinder 67 fixed to the secondary shaft 52 is provided on the opposite side of the movable sheave 66 from the fixed sheave 65, and a piston chamber (oil chamber) 68 is formed between the movable sheave 66 and the cylinder 67. Yes. In the rotational axis direction, the positional relationship between the fixed sheave 65 and the movable sheave 66 is reversed from the positional relationship between the fixed sheave 61 and the movable sheave 62 of the primary pulley 53.

  In the continuously variable transmission mechanism 43, the hydraulic pressure supplied to the piston chambers 64 and 68 of the primary pulley 53 and the secondary pulley 54 is controlled, and the groove widths of the primary pulley 53 and the secondary pulley 54 are changed, so that the primary The pulley ratio between the pulley 53 and the secondary pulley 54 is continuously changed steplessly.

  Specifically, when the pulley ratio is decreased, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is increased. As a result, the movable sheave 62 of the primary pulley 53 moves to the fixed sheave 61 side, and the interval (groove width) between the fixed sheave 61 and the movable sheave 62 is reduced. Accordingly, the winding diameter of the belt 55 around the primary pulley 53 is increased, and the interval (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is increased. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is reduced.

  When the pulley ratio is increased, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is lowered. Thereby, the thrust of the secondary pulley 54 with respect to the belt 55 becomes larger than the thrust of the primary pulley 53 with respect to the belt 55, the interval between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is reduced, and the fixed sheave 61 and the movable sheave The distance from 62 increases. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is increased.

  On the other hand, the thrust of the primary pulley 53 and the secondary pulley 54 needs to be large enough to prevent slippage between the primary pulley 53 and the secondary pulley 54 and the belt 55. Therefore, the hydraulic pressure supplied to the piston chamber 68 of the secondary pulley 54 is controlled so that a thrust according to the magnitude of the torque input to the input shaft 41 is obtained.

  The reverse gear mechanism 44 is configured to transmit the power input to the input shaft 41 to the primary shaft 51 by reversely rotating and decelerating. Specifically, the reverse gear mechanism 44 includes an input shaft gear 71 formed integrally with the input shaft 41, a larger diameter and a larger number of teeth than the input shaft gear 71, and a rotation axis line by spline fitting to the primary shaft 51. And a primary shaft gear 72 that is supported so as to be movable in the direction and not to be relatively rotatable, and meshes with the input shaft gear 71.

  The planetary gear mechanism 45 includes a sun gear 81, a carrier 82, and a ring gear 83. The sun gear 81 is supported by the secondary shaft 52 so as to be movable in the rotational axis direction and not relatively rotatable by spline fitting. The carrier 82 is fitted on the output shaft 42 so as to be relatively rotatable. The carrier 82 rotatably supports a plurality of pinion gears 84. The plurality of pinion gears 84 are arranged on the circumference and mesh with the sun gear 81. The ring gear 83 has an annular shape that collectively surrounds the plurality of pinion gears 84, and meshes with the pinion gears 84 from the outside in the rotational radial direction of the secondary shaft 52. The ring gear 83 is fixed to the output shaft 42, and the ring gear 83 is provided so as to be integrally rotatable about the same rotational axis as the output shaft 42.

  The split drive gear 46 is fitted on the input shaft 41 so as to be relatively rotatable.

  The split driven gear 47 is provided so as to be integrally rotatable about the same rotation axis as the carrier 82 of the planetary gear mechanism 45. The split driven gear 47 is formed with a smaller diameter than the split drive gear 46 and has fewer teeth than the split drive gear 46.

  The power split type continuously variable transmission 3 includes clutches C1 and C2 and a brake B1.

  The clutch C1 is switched between an engaged state in which the input shaft 41 and the split drive gear 46 are directly coupled (coupled so as to be integrally rotatable) and a released state in which the direct coupling is released.

  The clutch C2 is switched between an engaged state in which the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are directly coupled (coupled so as to be integrally rotatable) and a released state in which the direct coupling is released.

  The brake B1 is switched between an engagement state in which the carrier 82 of the planetary gear mechanism 45 is braked and a release state in which the rotation of the carrier 82 is allowed.

<Transmission mode>
FIG. 2 is a diagram illustrating states of the clutches C1 and C2 and the brake B1 when the vehicle is moving forward and backward. In FIG. 2, “◯” indicates that the clutches C1 and C2 and the brake B1 are engaged. “X” indicates that the clutches C1, C2 and the brake B1 are in the released state. FIG. 3 is a collinear diagram showing the relationship between the rotational speeds (rotational speeds) of the sun gear 81, the carrier 82, and the ring gear 83 of the planetary gear mechanism 45.

  The power split type continuously variable transmission 3 has a belt mode and a split mode as shift modes in the forward range.

  In the belt mode, as shown in FIG. 2, the clutch C1 and the brake B1 are released, and the clutch C2 is engaged. As a result, the split drive gear 46 is disconnected from the input shaft 41, the carrier 82 of the planetary gear mechanism 45 becomes free (free rotation state), and the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are directly connected.

  The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 to rotate the primary shaft 51 and the primary pulley 53. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. Since the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are directly connected, the sun gear 81, the ring gear 83, and the output shaft 42 rotate together with the secondary shaft 52. Therefore, in the belt mode, as shown in FIG. 3, the gear ratio (unit gear ratio) of the power split type continuously variable transmission 3 matches the pulley ratio.

  In the split mode, as shown in FIG. 2, the clutch C1 is engaged, and the clutch C2 and the brake B1 are released. Thereby, the input shaft 41 and the split drive gear 46 are directly connected, the carrier 82 of the planetary gear mechanism 45 becomes free, and the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are disconnected.

  The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43, and is transmitted from the primary shaft 51 via the primary pulley 53, the belt 55 and the secondary pulley 54. Is transmitted to the secondary shaft 52 and transmitted to the sun gear 81 of the planetary gear mechanism 45. On the other hand, the power input to the input shaft 41 is accelerated and transmitted from the split drive gear 46 to the carrier 82 of the planetary gear mechanism 45 through the split driven gear 47.

  Since the gear ratio between the split drive gear 46 and the split driven gear 47 is constant and unchanged (fixed), in the split mode, if the power input to the input shaft 41 is constant, the carrier 82 of the planetary gear mechanism 45 rotates. Is maintained at a constant speed. For this reason, when the pulley ratio is increased, the rotational speed of the sun gear 81 of the planetary gear mechanism 45 decreases, so that the rotational speed of the ring gear 83 (output shaft 42) of the planetary gear mechanism 45 is reduced as shown by a broken line in FIG. Go up. As a result, in the split mode, the gear ratio of the continuously variable transmission mechanism 43 decreases as the pulley ratio increases.

  The rotation of the output shaft 42 in the belt mode and the split mode is transmitted to the differential gear 6 via the output gear 48. As a result, the drive shafts 7 and 8 of the vehicle rotate in the forward direction.

  In the reverse range, the reverse mode is set, and the clutches C1 and C2 are engaged and the brake B1 is released as shown in FIG. Thereby, the split drive gear 46 is disconnected from the input shaft 41, the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are disconnected, and the carrier 82 of the planetary gear mechanism 45 is braked.

  The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43, and is transmitted from the primary shaft 51 via the primary pulley 53, the belt 55 and the secondary pulley 54. Then, the sun gear 81 of the planetary gear mechanism 45 is rotated integrally with the secondary shaft 52. Since the carrier 82 of the planetary gear mechanism 45 is braked, when the sun gear 81 rotates, the ring gear 83 of the planetary gear mechanism 45 rotates in the opposite direction to the sun gear 81. The rotation direction of the ring gear 83 is opposite to the rotation direction of the ring gear 83 during forward movement (belt mode and split mode). Then, the output shaft 42 rotates integrally with the ring gear 83. The rotation of the output shaft 42 is transmitted to the differential gear 6 via the output gear 48. Thereby, the drive shafts 7 and 8 of the vehicle rotate in the reverse direction.

<Position relationship between torque converter and output shaft>
FIG. 4 is a cross-sectional view showing the positional relationship between the torque converter 2 and the output shaft 42 of the power split type continuously variable transmission 3. Also in FIG. 4, the hatching indicating the cross section is omitted.

  In the power split type continuously variable transmission 3, a large inter-shaft distance between the input shaft 41 and the output shaft 42 can be secured due to the restriction due to the gear ratio of the split drive gear 46 and the split driven gear 47 (see FIG. 1). The distance between the shafts is the distance between the rotation axis of the torque converter 2 and the outer peripheral end of the clutch damper portion 102 where the lockup mechanism 15 (the lockup piston 21 and the damper mechanism 22) is disposed, that is, the clutch damper portion 102 Designed to be almost the same as the turning radius.

  Under this design, in order to avoid interference between the torque converter 2 and the output shaft 42, when the positions in the rotational axis direction are shifted from each other, the total length of the transmission unit 1 in the rotational axis direction becomes large, and the transmission unit 1 Mountability on the vehicle is reduced.

  Therefore, the torque converter 2 is designed such that the outer diameter of the torus portion 101 where the pump impeller 12 and the turbine runner 14 are disposed is smaller than the outer diameter of the clutch damper portion 102. In other words, the outer diameter of the clutch damper portion 102 is designed to be larger than the outer diameter of the torus portion 101. Therefore, the outer peripheral end portion 103 of the clutch damper portion 102 protrudes in a hook shape on the outer side in the rotational radial direction with respect to the torus portion 101.

  Then, the shaft length of the input shaft 41 is shortened to such a dimension that the portion of the unit case 4 that houses the engine-side end portion 104 of the output shaft 42 does not come into contact with the clutch damper portion 102. Thereby, the end 104 of the output shaft 42 overlaps a part of the torus part 101 in the rotational radial direction, and overlaps the outer peripheral end 103 of the clutch damper part 102 in the rotational axis direction.

<Effect>
As described above, the torque converter 2 includes the front cover 11, the pump impeller 12, the turbine runner 14, and the lockup mechanism 15. The pump impeller 12 is disposed on the side opposite to the engine side with respect to the front cover 11. The turbine runner 14 is accommodated in a space between the front cover 11 and the pump impeller 12. The lockup mechanism 15 is disposed between the turbine runner 14 and the front cover 11. The automatic transmission includes an input shaft 41 and an output shaft 42. The input shaft 41 and the output shaft 42 are parallel to each other with a space therebetween.

  A part of the torus portion 101 in which the pump impeller 12 and the turbine runner 14 are disposed overlaps (opposites) with the end portion 104 on the engine side of the output shaft 42 in the rotational radial direction. Thereby, compared with the configuration in which the torque converter 2 is completely displaced in the axial direction with respect to the output shaft 42, the overall length in the axial direction (unit overall length) of the transmission unit 1 can be shortened. it can.

  In addition, a part of the clutch damper portion 102 where the lockup mechanism 15 is disposed overlaps (opposes) the output shaft 42 in the rotation axis direction. As a result, the radial size of the lockup mechanism 15 can be increased while avoiding interference between the torque converter 2 and the output shaft 42. By increasing the radial size of the lockup mechanism 15, the transmission torque capacity of the lockup mechanism 15 can be increased without increasing the lockup hydraulic pressure (hydraulic pressure acting on the lockup piston 21 in the lockup state). .

  Therefore, it is possible to increase the transmission torque capacity of the lockup mechanism 15 while suppressing deterioration of fuel consumption and expansion of the entire unit length.

  The lockup mechanism 15 is provided with a damper mechanism 22 for attenuating vibrations from the engine when the pump impeller 12 and the turbine runner 14 are directly connected. Thereby, the size of the damper mechanism 22 in the radial direction can be increased while avoiding interference between the torque converter 2 and the output shaft 42. Since the radial size of the damper mechanism 22 can be increased, the stopper torque of the damper mechanism 22 can be increased, and the vibration input to the torque converter 2 can be effectively damped by the damper mechanism 22. it can.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, the power split type continuously variable transmission 3 has been taken up as an example of an automatic transmission. However, the present invention is not limited to the power split type continuously variable transmission 3, but a known continuously variable transmission (CVT: Continuously Variable Transmission). ), And can be widely applied to a transmission unit including a stepped automatic transmission (AT).

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

DESCRIPTION OF SYMBOLS 1 Transmission unit 2 Torque converter 3 Power split type continuously variable transmission (automatic transmission)
11 Front cover 12 Pump impeller 14 Turbine runner 15 Lockup mechanism 41 Input shaft (first shaft)
42 Output shaft (second shaft)
101 Torus part 102 Clutch damper part 103 Outer peripheral edge part 104 End part

Claims (1)

A transmission unit including a torque converter and an automatic transmission,
The torque converter
A front cover to which the driving force from the engine is input;
A pump impeller provided on the opposite side of the engine side with respect to the front cover, fixed to the front cover, and forming a space between the front cover;
A turbine runner accommodated in a space between the front cover and the pump impeller;
A lock-up mechanism that is provided between the front cover and the turbine runner and directly connects / separates the front cover and the turbine runner by hydraulic pressure;
The automatic transmission is
A first shaft connected to the turbine runner so as not to rotate relative to the turbine runner;
A second axis provided parallel to the first axis at an interval,
At least a part of the torus portion where the pump impeller and the turbine runner in the torque converter are arranged overlaps with an end portion on the engine side of the second shaft in the radial direction of the second shaft,
A part of the clutch damper portion in which the lockup mechanism in the torque converter is disposed overlaps the second shaft in the axial direction of the second shaft.

Images