JP7451031B2 - transmission - Google Patents

Description

The present invention relates to a transmission.

For example, in a vehicle equipped with a transmission, engine power is input to the transmission via a torque converter, and the power changed by the transmission is transmitted to the drive wheels via a differential gear, etc. . As a transmission, a continuously variable transmission (CVT) and a stepped automatic transmission (AT) are widely known.

In a belt-type continuously variable transmission, the input shaft into which power from the engine is input is connected to the primary shaft of the continuously variable transmission mechanism so that power can be transmitted, and the power input to the input shaft is transmitted from the input shaft. transmitted to the primary axis. In a continuously variable transmission mechanism, a secondary shaft is arranged parallel to the primary shaft with a gap between them, and an endless belt is wound between the primary pulley supported by the primary shaft and the secondary pulley supported by the secondary shaft. It is being Thereby, the power transmitted from the input shaft to the primary shaft is transmitted from the primary pulley to the belt, and from the belt to the secondary pulley. The power transmitted to the secondary pulley is then transmitted to the output shaft via the secondary shaft, and the power is transmitted from the output shaft to the left and right drive wheels via the differential gear.

Further, the continuously variable transmission includes a forward/reverse switching mechanism for switching the vehicle between forward and backward movement. As one type of forward/reverse switching mechanism, a parallel shaft gear type in which a reverse idler shaft is provided parallel to an input shaft is known. In a parallel shaft gear type, for example, by engaging/releasing a reverse clutch placed on the primary shaft, the path for transmitting power from the input shaft to the output shaft is divided into a path via the reverse idler shaft and a path via the reverse idler shaft. It is possible to switch to a route that does not go through . By switching the power transmission path, the direction of the power transmitted to the output shaft is switched (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2013-113304

However, in the conventional configuration, the gear to which power is transmitted from the reverse idler shaft is arranged coaxially with the reverse clutch, which increases the size of the unit including the continuously variable transmission.

An object of the present invention is to provide a transmission that can be downsized.

In order to achieve the above object, a transmission according to the present invention has an input shaft into which power from a drive source is input, a primary shaft and a secondary shaft each extending parallel to the input shaft, and a transmission from the primary shaft. a continuously variable transmission mechanism that changes the speed and transmits power to the secondary shaft; a gear that is supported by the secondary shaft and into which power is input from the input shaft without passing through the primary shaft; a clutch that transmits/cuts off power between the primary shaft and the secondary shaft, the primary shaft and the secondary shaft are arranged to sandwich the input shaft, and a part of the gear is disposed between the input shaft and the clutch. The input shaft overlaps the clutch in the axial direction of the input shaft.

According to this configuration, the primary shaft and the secondary shaft are provided in parallel to the input shaft. The secondary shaft supports a gear to which power is input from the input shaft without passing through the primary shaft. Further, a clutch is provided on the secondary shaft to transmit/cut off power between the secondary shaft and the gear.

The primary axis and the secondary axis are arranged with the input axis sandwiched between them. Thereby, the distance between the input shaft and the primary shaft and the distance between the input shaft and the secondary shaft can be shortened.

Further, the gear is disposed between the input shaft and the clutch so that a portion of the gear overlaps the clutch in the axial direction of the input shaft. Thereby, it is possible to reduce the size of the transmission in the axial direction.

Therefore, the transmission can be made smaller in the radial direction and also in the axial direction. Along with this downsizing, each member such as the case that forms the outer shell of the transmission is also downsized, making it possible to reduce the weight and cost of the transmission.

Preferably, the transmission further includes an oil pump disposed on the axis of the input shaft, and the clutch and the oil pump are disposed so that at least a portion of each other overlaps in the axial direction.

With this configuration, it is possible to further reduce the size of the transmission in the axial direction, and the reduction in size allows weight and cost reduction.

According to the present invention, it is possible to downsize the transmission.

FIG. 1 is a sectional view showing the configuration of a transmission unit according to an embodiment of the present invention. FIG. 2 is a skeleton diagram schematically showing the configuration of a CVT. FIG. 2 is a cross-sectional view showing a configuration between an input shaft and a secondary shaft on a larger scale than in FIG. 1;

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

<Transmission unit>
FIG. 1 is a sectional view showing the configuration of a transmission unit 1 according to an embodiment of the present invention. Note that in the cross-sectional views shown in FIG. 1 and subsequent figures, hatching representing the cross-section is omitted.

The transmission unit 1 is a unit that is mounted on a vehicle and changes the speed of power generated by an engine 2 (E/G) 2 as a drive source for driving. The vehicle uses an FR (front engine, rear drive) layout.

The engine 2 is, for example, a three-cylinder, four-stroke engine, and is mounted vertically with the crankshaft oriented vertically with respect to the longitudinal direction of the vehicle body. The number of cylinders in the engine 2 is not limited to three, but may be four or more, or two or less. Further, the number of strokes of the engine 2 is not limited to four strokes, but may be two strokes.

The transmission unit 1 includes a torque converter 4 and a CVT (Continuously Variable Transmission) 5 within a unit case 3 forming an outer shell.

<Unit case>
The unit case 3 is composed of three parts: a first case 11, a second case 12, and a third case 13. The first case 11, the second case 12, and the third case 13 are made of, for example, an aluminum alloy and are cast by a die-casting method.

The first case 11, the second case 12, and the third case 13 are arranged in this order from the front side (engine 2 side). The first case 11 and the second case 12 are fastened with bolts, and the second case 12 and third case 13 are fastened with bolts 17, so that the first case 11, the second case 12, and the third case 13 are integrated.

<Torque converter>
Torque converter 4 is housed within first case 11 . The torque converter 4 includes a front cover 21, a pump impeller 22, a turbine hub 23, a turbine runner 24, a lockup mechanism 25, and a stator 26.

The front cover 21 extends in a substantially disk shape around a rotational axis extending in the longitudinal direction of the vehicle (vehicle body), and its outer peripheral end is on the side opposite to the engine 2 side (on the side of the continuously variable transmission mechanism 42 described later). It has a shape that is bent to the side. The center of the front cover 21 bulges forward. The crankshaft of the engine 2 is coupled to this bulged portion in a relatively non-rotatable manner.

The pump impeller 22 is arranged on the rear side of the front cover 21. An outer circumferential end of the pump impeller 22 is connected to an outer circumferential end of the front cover 21, and is provided so as to be able to rotate integrally with the front cover 21 about the rotation axis. A plurality of blades 27 are arranged radially on the inner surface of the pump impeller 22 .

Turbine hub 23 is arranged between front cover 21 and pump impeller 22.

Turbine runner 24 is fixed to turbine hub 23. A plurality of blades 28 are arranged radially on the surface of the turbine runner 24 facing the pump impeller 22 .

The lockup mechanism 25 includes a lockup piston 31 and a damper mechanism 32.

The lockup piston 31 has a substantially annular plate shape, an inner peripheral end thereof is fitted onto the turbine hub 23, and is located between the front cover 21 and the turbine runner 24. When the oil pressure in the engagement side oil chamber 33 on the turbine runner 24 side with respect to the lockup piston 31 is higher than the oil pressure in the release side oil chamber 34 on the front cover 21 side, the lockup piston 31 moves toward the front cover due to the differential pressure. Move to the 21 side. When the lockup piston 31 is pressed against the front cover 21, the pump impeller 22 and the turbine runner 24 are directly coupled (locked on). Conversely, when the oil pressure in the release side oil chamber 34 is higher than the oil pressure in the engagement side oil chamber 33, the lockup piston 31 moves toward the turbine runner 24 due to the pressure difference. When the lock-up piston 31 is separated from the front cover 21, the direct connection between the pump impeller 22 and the turbine runner 24 is released (lock-up off).

The damper mechanism 32 is a mechanism for damping vibrations from the engine 2 when the pump impeller 22 and the turbine runner 24 are directly connected.

Stator 26 is arranged between pump impeller 22 and turbine runner 24.

When the pump impeller 22 rotates due to engine torque in the lock-up off state, oil flows from the pump impeller 22 toward the turbine runner 24. This oil flow is received by the blades 28 of the turbine runner 24, causing the turbine runner 24 to rotate. At this time, the amplification effect of the torque converter 4 occurs, and a torque larger than the engine torque is generated in the turbine runner 24.

<CVT>
The CVT 5 is housed in a second case 12 and a third case 13. The CVT 5 includes an input shaft 41, a continuously variable transmission mechanism 42, an output shaft 43, and a reverse transmission mechanism 44. The transmission unit 1 is disposed on the rear side of the engine 2 so that the input shaft 41 of the CVT 5 is vertically oriented so as to extend in the longitudinal direction of the vehicle, and the input shaft 41 is arranged to be inclined downward toward the rear.

Input shaft 41 is formed into a hollow shaft and extends on the rotation axis of torque converter 4 . The front end of the input shaft 41 is inserted into the torque converter 4 and spline-fitted to the turbine hub 23.

Note that in the following description, the direction in which the axis (axis center) of the input shaft 41 extends is referred to as the "axial direction." Further, the direction perpendicular to the axial direction, that is, the radial direction of the input shaft 41 is referred to as the "axial radial direction."

A rear end portion of the input shaft 41 is rotatably supported by a mechanical oil pump 45 disposed within the second case 12 . Specifically, the oil pump 45 includes a pump case 46, a pump cover 47 joined to the pump case 46 from the rear side, a pump gear 48 disposed in a space inside the pump case 46, and a pump gear 48 that cannot rotate relative to the pump gear 48. A pump shaft 49 coupled to the pump shaft 49 is provided. The pump cover 47 is fixed to the second case 12 and closes off the space inside the pump case 46 from the rear side. A bearing recess 51 is formed at the front end of the pump case 46 and is open toward the front and recessed toward the rear in a substantially cylindrical shape. The rear end of the input shaft 41 is inserted into the bearing recess 51 and rotated by the pump case 46 via a ball bearing 52 interposed between the peripheral surface of the input shaft 41 and the inner peripheral surface of the bearing recess 51. Possibly supported. In other words, the ball bearing 52 is fitted onto the rear end of the input shaft 41 , and the ball bearing 52 is fitted into the bearing recess 51 , so that the rear end of the input shaft 41 is connected to the pump via the ball bearing 52 . It is rotatably supported by a case 46.

The pump shaft 49 is provided to penetrate the pump case 46 and the pump cover 47. The pump shaft 49 extends forward from the pump case 46 and is inserted into the input shaft 41 with a gap between the input shaft 41 and the inner peripheral surface thereof. The front end of the pump shaft 49 reaches the front cover 21 of the torque converter 4, and is connected to the center of the front cover 21 in a relatively non-rotatable manner. As a result, when the front cover 21 is rotated by the power of the engine 2, the pump shaft 49 and the pump gear 48 are rotated together with the front cover 21, and oil pressure is generated from the oil pump 45.

The continuously variable transmission mechanism 42 includes a primary shaft 54, a secondary shaft 55, a primary pulley 56, a secondary pulley 57, and a belt 58.

The primary shaft 54 and the secondary shaft 55 extend parallel to the input shaft 41 between the first case 11 and the second case 12, and are rotatably provided around their axes.

The primary pulley 56 includes a primary fixed sheave 61 fixed to the primary shaft 54, and a primary disposed opposite to the primary fixed sheave 61 with a belt 58 interposed therebetween, and supported by the primary shaft 54 so as to be movable in the axial direction and relatively non-rotatable. A movable sheave 62 is provided. The primary movable sheave 62 is arranged on the front side with respect to the primary fixed sheave 61. A cylinder 63 is provided on the side opposite to the primary fixed sheave 61 side with respect to the primary movable sheave 62, that is, on the front side, and a hydraulic chamber (piston chamber) 64 is formed between the primary movable sheave 62 and the cylinder 63. ing.

The secondary pulley 57 includes a secondary fixed sheave 65 fixed to the secondary shaft 55 and a secondary sheave 65 which is disposed opposite to the secondary fixed sheave 65 with a belt 58 interposed therebetween, and which is supported by the secondary shaft 55 so as to be movable in the axial direction and non-rotatable relative to the secondary shaft 55. A movable sheave 66 is provided. The secondary movable sheave 66 is arranged on the rear side with respect to the secondary fixed sheave 65. A piston 67 is provided on the opposite side of the secondary movable sheave 66 from the secondary fixed sheave 65, that is, on the rear side, and a hydraulic chamber 68 is formed between the secondary movable sheave 66 and the piston 67.

The belt 58 is formed into an endless shape, and is wound around the primary pulley 56 while being sandwiched between the primary fixed sheave 61 and the primary movable sheave 62, and is also wound between the secondary fixed sheave 65 and the secondary movable sheave 66. It is wound around the secondary pulley 57 in a pinched state.

In the continuously variable transmission mechanism 42, the hydraulic pressure supplied to the hydraulic chambers 64, 68 of the primary pulley 56 and the secondary pulley 57 is controlled, and the groove widths of the primary pulley 56 and secondary pulley 57 are changed. The gear ratio (the pulley ratio between the primary pulley 56 and the secondary pulley 57) is continuously and steplessly changed within a fixed gear ratio range.

Specifically, when the belt transmission ratio is decreased, the hydraulic pressure supplied to the hydraulic chamber 64 of the primary pulley 56 is increased. As a result, the primary movable sheave 62 of the primary pulley 56 moves toward the primary fixed sheave 61, and the interval (groove width) between the primary fixed sheave 61 and the primary movable sheave 62 becomes smaller. Accordingly, the winding diameter of the belt 58 around the primary pulley 56 increases, and the interval (groove width) between the secondary fixed sheave 65 and the secondary movable sheave 66 of the secondary pulley 57 increases. As a result, the belt transmission ratio becomes smaller.

When the belt speed ratio is increased, the hydraulic pressure supplied to the hydraulic chamber 64 of the primary pulley 56 is lowered. As a result, the thrust force of the secondary pulley 57 with respect to the belt 58 becomes larger than the thrust force of the primary pulley 56 with respect to the belt 58, the interval between the secondary fixed sheave 65 and the secondary movable sheave 66 of the secondary pulley 57 becomes smaller, and the primary fixed sheave 61 and the primary movable sheave 62 becomes larger. As a result, the belt transmission ratio increases.

A bias spring 69 is provided in the hydraulic chamber 68 of the secondary pulley 57. The bias spring 69 has one end in elastic contact with the secondary movable sheave 66 and the other end in elastic contact with the piston 67. The elastic force of the bias spring 69 urges the secondary movable sheave 66 and the piston 67 in a direction away from each other. A biasing force is applied to the secondary movable sheave 66 by the hydraulic pressure in the hydraulic chamber 68 and a bias spring 69, and a corresponding pinching pressure is applied to the belt 58.

Further, an input gear 81 is integrally formed in the center of the input shaft 41 in the axial direction. Correspondingly, a primary input gear 82 that meshes with an input gear 81 is supported on the primary shaft 54 so as to be relatively rotatable. A forward clutch 83 is provided that allows/prohibits rotation of the primary input gear 82 with respect to the primary shaft 54 by utilizing the space between the input gear 81 and the primary input gear 82 and the oil pump 45 that mesh with each other. . A portion of the forward clutch 83 overlaps the oil pump 45 in the axial radial direction (overlapping when viewed in the axial direction).

Forward clutch 83 includes a clutch drum 84, a clutch hub 85, and a clutch piston 86. The clutch drum 84 has an inner peripheral end fixed to the primary shaft 54, extends from the primary shaft 54 in the shaft radial direction, and an outer peripheral end bent and extends toward the primary input gear 82, that is, toward the front. The clutch hub 85 is formed integrally with the primary input gear 82, has a cylindrical shape extending rearward from the primary input gear 82, and is spaced apart from the inner side in the radial direction of the shaft relative to the outer peripheral end of the clutch drum 84. They are facing each other. Clutch piston 86 is provided between clutch drum 84 and clutch hub 85 so as to be movable in the axial direction. The clutch piston 86 is in fluid-tight contact with the clutch drum 84, and a hydraulic chamber 87 is formed between the clutch drum 84 and the clutch piston 86 to which hydraulic pressure acting on the clutch piston 86 is supplied. . Further, the clutch piston 86 is elastically biased rearward by a return spring 88.

In a space sandwiched between the outer peripheral end of the clutch drum 84 and the clutch hub 85 in the axial radial direction, clutch plates held by the clutch drum 84 and clutch discs held by the clutch hub 85 are arranged alternately in the axial direction. There is. When the clutch piston 86 moves forward and presses the clutch plate from the rear side by the hydraulic pressure supplied to the hydraulic chamber 87, the clutch plate and the clutch disk come into pressure contact, and the forward clutch 83 is engaged. Engagement of forward clutch 83 inhibits rotation of primary input gear 82 with respect to primary shaft 54, and when primary input gear 82 rotates, primary shaft 54 rotates together with primary input gear 82. When the hydraulic pressure is released from the engaged state of the forward clutch 83, the clutch piston 86 moves rearward due to the biasing force of the return spring 88, the pressure contact between the clutch disc and the clutch plate is released, and the forward clutch 83 is released. To be released. By disengaging the forward clutch 83, rotation of the primary input gear 82 with respect to the primary shaft 54 is allowed, and even if the primary input gear 82 rotates, the rotation is not transmitted to the primary shaft 54.

A secondary input gear 91 is supported by the secondary shaft 55 so as to be relatively rotatable. Secondary input gear 91 is arranged between input gear 81 and oil pump 45 in the axial direction. Further, a reverse clutch 92 is provided that utilizes the space between the secondary input gear 91 and the oil pump 45 to allow/prohibit rotation of the secondary input gear 91 with respect to the secondary shaft 55. A portion of the reverse clutch 92 overlaps the oil pump 45 in the radial direction (overlapping when viewed in the axial direction).

The reverse clutch 92 includes a clutch drum 93, a clutch hub 94, and a clutch piston 95. The clutch drum 93 has an inner peripheral end fixed to the secondary shaft 55, extends from the secondary shaft 55 in the shaft radial direction, and an outer peripheral end bent and extends toward the secondary input gear 91 side, that is, toward the front side. The clutch hub 94 is formed integrally with the secondary input gear 91, has a cylindrical shape extending rearward from the secondary input gear 91, and is spaced apart from the inner side in the axial radial direction with respect to the outer peripheral end of the clutch drum 93. They are facing each other. Clutch piston 95 is provided between clutch drum 93 and clutch hub 94 so as to be movable in the axial direction. The clutch piston 95 is in liquid-tight contact with the clutch drum 93, and a hydraulic chamber 96 is formed between the clutch drum 93 and the clutch piston 95 to which hydraulic pressure acting on the clutch piston 95 is supplied. . Further, the clutch piston 95 is elastically urged rearward by a return spring 97.

In a space sandwiched between the outer peripheral end of the clutch drum 93 and the clutch hub 94 in the axial radial direction, clutch plates held by the clutch drum 93 and clutch discs held by the clutch hub 94 are arranged alternately in the axial direction. There is. When the clutch piston 95 moves forward and presses the clutch plate from the rear side by the hydraulic pressure supplied to the hydraulic chamber 96, the clutch plate and the clutch disk come into pressure contact, and the reverse clutch 92 is engaged. By engaging the reverse clutch 92, rotation of the secondary input gear 91 with respect to the secondary shaft 55 is prohibited, and when the secondary input gear 91 rotates, the secondary shaft 55 rotates together with the secondary input gear 91. When the hydraulic pressure is released from the engaged state of the reverse clutch 92, the clutch piston 95 moves rearward due to the biasing force of the return spring 97, the pressure contact between the clutch disc and the clutch plate is released, and the reverse clutch 92 is released. To be released. By releasing the reverse clutch 92, rotation of the secondary input gear 91 with respect to the secondary shaft 55 is allowed, and even if the secondary input gear 91 rotates, the rotation is not transmitted to the secondary shaft 55.

The output shaft 43 is disposed on the same axis as the input shaft 41 with a space on the rear side relative to the input shaft 41. In other words, the input shaft 41 and the output shaft 43 are arranged front and rear with an interval in the axial direction, respectively, so as to have a common axis extending vertically along the longitudinal direction of the vehicle. An output transmission gear 101 is integrally formed with the output shaft 43. Correspondingly, a secondary output gear 102 that meshes with the output transmission gear 101 is supported on the secondary shaft 55 so as not to be relatively rotatable.

The reverse transmission mechanism 44 is a mechanism that transmits the power (rotation) of the input shaft 41 to the secondary input gear 91. The reverse transmission mechanism 44 includes a reverse idler shaft 103, a first reverse gear 104, and a second reverse gear 105. The reverse idler shaft 103 extends in the axial direction, straddles the first case 11 and the second case 12, and is rotatably supported by the first case 11 and the second case 12. The first reverse gear 104 is formed integrally with the reverse idler shaft 103 and meshes with the input gear 81. The second reverse gear 105 is formed integrally with the reverse idler shaft 103 on the rear side of the first reverse gear 104 and meshes with the secondary input gear 91.

An adapter 111 is provided between the output shaft 43 and the primary shaft 54. The adapter 111 is made of, for example, an aluminum alloy, and is a casting cast by die-casting. The adapter 111 extends between the output shaft 43 and the primary shaft 54 in the shaft radial direction. The upper end of the adapter 111 protrudes rearward, and a substantially cylindrical recess 112 is formed in the protruding portion toward the front. The front end of the output shaft 43 is inserted into the recess 112. A radial bearing 113 is interposed between the circumferential surface of the output shaft 43 and the inner circumferential surface of the recess 112. The front end of the output shaft 43 is rotatably supported by the adapter 111 via a radial bearing 113. Further, the output shaft 43 has an annular stepped surface along the shaft radial direction between the portion where the output transmission gear 101 is formed and the portion inserted into the recess 112. A thrust bearing 114 is interposed between the stepped surface and the adapter 111. Thereby, the front end portion of the output shaft 43 is rotatably supported by the adapter 111 via the radial bearing 113 and the thrust bearing 114.

Further, the adapter 111 has a substantially cylindrical recess 115 formed on the rear side. The rear end portion of the primary shaft 54 is inserted into the recess 115. A ball bearing 116 is interposed between the circumferential surface of the primary shaft 54 and the inner circumferential surface of the recess 115. A rear end portion of the primary shaft 54 is rotatably supported by the adapter 111 via a ball bearing 116.

A bolt 117 is inserted into the lower end of the adapter 111 from the front side. The adapter 111 is attached to the third case 13 by the bolt 117.

<Oil supply structure>
A valve body 121 for controlling oil supply to each part of the transmission unit 1 is provided at the bottom of the second case 12.

Further, a strainer 122 is provided at the bottom of the second case 12. The strainer 122 includes a filtration part 123 arranged side by side with the valve body 121 and a pipe part 124 extending from the filtration part 123. The pipe portion 124 extends forward from the lower portion of the filter portion 123 and extends below the valve body 121 . The tube portion 124 is formed into a hollow tube shape that communicates with the inside of the filter portion 123 .

An oil pan 125 is fixed to the second case 12 from below with a plurality of bolts 126. A tip 127 of the pipe portion 124 of the strainer 122 is located in the center of the oil pan 125, and a suction port for sucking oil is formed on the lower surface of the tip 127.

A suction force is generated by the rotation of the pump gear 48 of the oil pump 45, and the oil accumulated in the oil pan 125 is sucked into the pipe portion 124 from the suction port. The oil sucked into the pipe part 124 flows inside the pipe part 124 toward the filter part 123 and passes through a filter material provided in the filter part 123. As the oil passes through the filter medium, foreign substances contained in the oil are captured by the filter medium and removed from the oil. The oil that has passed through the filter material is supplied to the valve body 121 via the oil pump 45. Then, oil is supplied as hydraulic oil or lubricating oil from the valve body 121 to various parts such as the continuously variable transmission mechanism 42 that require oil supply.

<Power transmission path>
FIG. 2 is a skeleton diagram schematically showing the configuration of the CVT 5. As shown in FIG.

When the vehicle moves forward, the forward clutch 83 is engaged and the reverse clutch 92 is released. Power input from the engine 2 to the input shaft 41 via the torque converter 4 is transmitted from the input gear 81 to the primary shaft 54 via the primary input gear 82 by engagement of the forward clutch 83. On the other hand, even if the power input to the input shaft 41 is transmitted from the input gear 81 to the secondary input gear 91 and the secondary input gear 91 rotates, the secondary input gear 91 is not connected to the secondary shaft 55 due to the release of the reverse clutch 92. On the other hand, it idles and no power is transmitted to the secondary shaft 55.

The power transmitted to the primary shaft 54 is transmitted to the secondary shaft 55 after being changed in speed at a belt speed ratio according to the pulley ratio of the primary pulley 56 and the secondary pulley 57. The power transmitted to the secondary shaft 55 is transmitted from the secondary output gear 102 to the output shaft 43 via the output transmission gear 101.

When the vehicle is traveling backwards, the forward clutch 83 is released and the reverse clutch 92 is engaged. Power input from the engine 2 to the input shaft 41 via the torque converter 4 is transmitted from the input gear 81 to the secondary shaft 55 via the reverse transmission mechanism 44 and the secondary input gear 91 by engagement of the reverse clutch 92. . At this time, the secondary shaft 55 rotates in the opposite direction to when the vehicle moves forward. On the other hand, even if the power input to the input shaft 41 is transmitted from the input gear 81 to the primary input gear 82 and the primary input gear 82 rotates, the primary input gear 82 is transferred to the primary shaft 54 due to the release of the forward clutch 83. On the other hand, it idles and no power is transmitted to the primary shaft 54.

The power transmitted to the secondary shaft 55 is transmitted from the secondary output gear 102 to the output shaft 43 via the output transmission gear 101.

The power transmitted to the output shaft 43 is output from the output shaft 43 to the propeller shaft, and is transmitted from the propeller shaft to the left and right rear wheels via a rear differential gear (rear differential) and a drive shaft.

<Configuration between input axis and secondary axis>
FIG. 3 is a cross-sectional view showing the configuration between the input shaft 41 and the secondary shaft 55 on a larger scale than in FIG. 1. As shown in FIG.

As described above, the clutch drum 93 of the reverse clutch 92 has an inner peripheral end fixed to the secondary shaft 55, extends from the secondary shaft 55 in the shaft radial direction, and an outer peripheral end bent toward the secondary input gear 91, that is, toward the front. It extends. More specifically, the clutch drum 93 includes a generally annular plate-shaped flange portion 131 extending in the shaft radial direction from the secondary shaft 55, and a flange portion 131 extending from the outer peripheral end of the flange portion 131 toward the front side along the axial direction. It integrally includes an extending flat cylindrical portion 132 having a generally cylindrical shape and a generally cylindrical cylindrical portion 133 further extending forward from the flat cylindrical portion 132 along the axial direction. An end portion on the inner peripheral side of the brim portion 131 is fixed to the secondary shaft 55 by welding. The outer circumferential surface 134 of the flat cylindrical portion 132 is lowered toward the axis of the secondary shaft 55 with respect to the outer circumferential surface 135 of the cylindrical portion 133, and there is a gap between the outer circumferential surface 134 of the flat cylindrical portion 132 and the outer circumferential surface 135 of the cylindrical portion 133. , there are steps that are smoothly connected by a curved surface 136.

A front end portion of the pump case 46 of the oil pump 45 overlaps the clutch drum 93 in the axial direction. More specifically, the front end portion of the pump case 46 faces the outer circumferential surface 134 of the flat cylindrical portion 132 of the clutch drum 93 with an interval in the axial radial direction. Further, at the front end of the pump case 46 , an inclined surface 137 is formed around the bearing recess 51 so as to be inclined closer to the axis of the input shaft 41 toward the front. This inclined surface 137 faces the curved surface 136 of the clutch drum 93 in a direction perpendicular to the inclined surface 137 with a space therebetween.

Further, an outer peripheral and rear end portion 141 of the secondary input gear 91 overlaps the clutch drum 93 in the axial direction. More specifically, the secondary input gear 91 integrally includes a substantially annular plate-shaped web 142 surrounding the secondary shaft 55 and a substantially cylindrical rim 143 surrounding the outer periphery of the web 142. A large number of teeth of the secondary input gear 91 are formed on the outer circumferential surface of the rim 143 so as to be lined up in the circumferential direction. A concave surface 144 having a substantially 1/4 circular cross section is formed at the connection portion of the web 142 with the rim 143. The front end of the cylindrical portion 133 of the clutch drum 93 faces the concave surface 144 at a distance in the axial direction, and also faces the concave surface 144 at a distance in the radial direction.

<Effect>
As described above, the primary shaft 54 and the secondary shaft 55 are provided parallel to the input shaft 41. A secondary input gear 91 to which power is input from the input shaft 41 without passing through the primary shaft 54 is supported by the secondary shaft 55 . Further, a reverse clutch 92 is provided on the secondary shaft 55 to transmit/cut off power between the secondary shaft 55 and the secondary input gear 91.

The primary shaft 54 and the secondary shaft 55 are arranged with the input shaft 41 sandwiched therebetween. Thereby, the distance between the input shaft 41 and the primary shaft 54 and the distance between the input shaft 41 and the secondary shaft 55 can be shortened.

Further, the secondary input gear 91 is disposed between the input shaft 41 and the reverse clutch 92 so that a portion thereof overlaps with the reverse clutch 92 in the axial direction. Thereby, the size of the transmission unit 1 in the axial direction can be reduced.

Therefore, the transmission unit 1 can be made smaller in the radial direction and also in the axial direction. Along with this miniaturization, each member such as the unit case 3 that forms the outer shell of the transmission unit 1 is also reduced in size, so that the weight and cost of the transmission unit 1 can be reduced.

Moreover, the reverse clutch 92 and the oil pump 45 are arranged so that a portion of each other overlaps in the axial direction. Thereby, it is possible to further reduce the size of the transmission unit 1 in the axial direction, and it is possible to achieve weight reduction and cost reduction due to the size reduction.

<Modified example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the embodiment described above, the transmission unit 1 is arranged vertically behind the engine 2, with the input shaft 41 of the CVT 5 extending vertically in the longitudinal direction of the vehicle. However, the present invention is not limited thereto, and can also be applied to a transmission unit that is placed horizontally on the left or right side of the engine 2 so that the input shaft of the CVT extends in the left-right direction of the vehicle.

Further, the power transmission system of the continuously variable transmission mechanism 42 is not limited to the belt type, but may be a chain type or a toroidal type.

Furthermore, the transmission mechanism provided in the transmission unit 1 is not limited to the continuously variable transmission mechanism 42, but may be a stepped transmission mechanism.

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

1: Transmission unit (transmission)
2: Engine (drive source)
41: Input shaft 42: Continuously variable transmission mechanism 45: Oil pump 54: Primary shaft 55: Secondary shaft 91: Secondary input gear (gear)
92: Reverse clutch (clutch)

Claims (2)

an input shaft into which power from the drive source is input;
a reverse idler shaft extending in the axial direction of the input shaft;
a continuously variable transmission mechanism having a primary shaft and a secondary shaft each extending parallel to the input shaft, and transmitting power from the primary shaft to the secondary shaft by changing the speed;
a gear supported by the secondary shaft and into which power is input from the input shaft via the reverse idler shaft without passing through the primary shaft ;
a clutch that transmits/cuts off power between the secondary shaft and the gear,
The primary shaft and the secondary shaft are arranged to sandwich the input shaft,
A part of the gear overlaps the clutch in the axial direction between the input shaft and the clutch. an input shaft into which power from the drive source is input;
a continuously variable transmission mechanism having a primary shaft and a secondary shaft each extending parallel to the input shaft, and transmitting power from the primary shaft to the secondary shaft by changing the speed;
a gear supported by the secondary shaft and into which power is input from the input shaft without passing through the primary shaft;
a clutch that transmits/cuts off power between the secondary shaft and the gear;
an oil pump disposed on the axis of the input shaft,
The primary shaft and the secondary shaft are arranged to sandwich the input shaft,
A portion of the gear overlaps the clutch in an axial direction of the input shaft between the input shaft and the clutch,
In the transmission , the clutch and the oil pump are arranged so that at least a portion of each other overlaps in the axial direction.

Images