JP7374551B2 - transmission - Google Patents

Description

The present invention relates to a transmission mounted on a vehicle.

In a vehicle equipped with an engine as a drive source for driving, power from the engine is transmitted to drive wheels via a transmission. Engines can be mounted either vertically, in which the crankshaft is oriented vertically with respect to the longitudinal direction of the vehicle, or horizontally, in which the crankshaft is oriented horizontally. In vehicles with a FF (Front-engine Front-wheel-drive) layout, for example, the engine is mounted horizontally in order to increase the cabin length by reducing the longitudinal size of the engine compartment. It is often done. On the other hand, in vehicles with an FR (Front-engine Rear-wheel-drive) layout, the engine is placed vertically to make it easier to transmit power to the rear wheels, which are the driving wheels. It may be installed.

On the other hand, as a transmission mounted on a vehicle, for example, a belt-type CVT (Continuously Variable Transmission) is widely known. In a belt-type CVT, 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 transferred from the input shaft to the primary shaft. communicated. 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.

The input shaft is rotatably supported by a case that forms the outer shell of the transmission. Bearings are used for this support. In particular, ball bearings are often used (for example, see Patent Document 1), and the arrangement and structure of the bearings often do not require much ingenuity. The included unit can be made smaller.

JP2013-257046A

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 is a transmission mounted on a vehicle, which extends from a first side that is a drive source side and a second side opposite thereto, and which is connected to a drive source side. an input shaft to which power is input; a ball bearing fitted externally to the input shaft; a radial bearing disposed in contact with the peripheral surface of the input shaft at a position on the second side with respect to the ball bearing; A radial bearing and a thrust bearing are arranged such that the outer diameter of the thrust bearing is larger than the inner diameter of the radial bearing, and the outer diameter of the roller provided in the thrust bearing is larger than the inner diameter of the radial bearing. It is designed so that the side end is located closer to the shaft center than the inner circumference of the radial bearing.

According to this configuration, a ball bearing is used to support the first side (drive source side) of the input shaft, and a radial bearing is used to support the second side of the input shaft. By using ball bearings, the input shaft can be easily positioned in the longitudinal direction.

On the other hand, by employing a radial bearing, the second side bearing portion of the input shaft can be downsized in the shaft radial direction, and the second side bearing portion can be arranged in a space-saving manner.

Further, since the thrust bearing is disposed in contact with the second end surface of the input shaft, it is possible to reduce mechanical loss due to rotation of the input shaft.

Moreover, since the outer diameter of the thrust bearing is larger than the inner diameter of the radial bearing, the length of the rollers provided in the thrust bearing can be ensured long, and by ensuring that length, the diameter of the rollers can be kept small. As a result, the thickness (dimension in the axial direction) of the thrust bearing can be kept small, and the size of the bearing portion on the second side of the input shaft can also be reduced in the axial direction.

Furthermore, since the outer circumference side ends of the rollers of the thrust bearing are located closer to the center than the inner circumference of the radial bearing, the force input from the input shaft can be received over the entire length of the rollers. Therefore, it is possible to prevent the thrust bearing from tilting in the shaft length direction and the shaft radial direction and contacting the end face of the input shaft, improving the durability (life) of the thrust bearing, and also increasing the rotation of the input shaft. Mechanical losses caused by this can be effectively reduced.

According to the present invention, the bearing portion on the second side of the input shaft can be downsized in the radial direction of the shaft, thereby making it possible to downsize the transmission in the radial direction of the shaft.

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 cross-sectional view showing a part of the transmission unit extracted from FIG. 1 and shown in an enlarged manner. FIG. 2 is a skeleton diagram showing a power transmission path in a CVT along with a configuration of the CVT. FIG. 3 is an enlarged cross-sectional view showing the configuration near the rear end of the input shaft.

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. FIG. 2 is an enlarged cross-sectional view of a part of the transmission unit 1 extracted from FIG. 1. As shown in FIG. 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 (E/G) as a drive source for driving. The vehicle adopts an FR layout, and the engine is, for example, a 3-cylinder, 4-stroke engine, which is mounted vertically with the crankshaft oriented vertically with respect to the longitudinal direction of the vehicle body. The transmission unit 1 includes a torque converter 3 and a CVT 4 inside a unit case 2 that forms an outer shell.

In addition, although the case where an engine is a 3 cylinder 4 stroke engine is taken up below, the number of cylinders of an engine is not limited to 3 cylinders, It may be 4 cylinders or more, and may be 2 cylinders or less. Further, the number of strokes of the engine is not limited to four strokes, but may be two strokes.

<Unit case>
The unit case 2 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 side), and the first case 11 and the second case 12 are fastened with bolts (not shown). The second case 12 and the third case 13 are integrated by being fastened with bolts 14. The torque converter 3 is housed in a first case 11, and the CVT 4 is housed in a second case 12 and a third case 13.

<Torque converter>
The torque converter 3 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 rear side, which is the side opposite to the engine side (the side of the continuously variable transmission mechanism 42 described later). It has a curved shape. The center of the front cover 21 bulges forward. The crankshaft of the engine 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. The outer circumferential end of the pump impeller 22 is connected to the outer circumferential end of the front cover 21, and is provided so as to be rotatable together 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 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 3 occurs, and a torque larger than the engine torque is generated in the turbine runner 24.

<Vertical CVT>
The CVT 4 includes an input shaft 41, a continuously variable transmission mechanism 42, a reverse transmission mechanism 43, and an output shaft 44. The CVT 4 is arranged such that the input shaft 41 is oriented vertically and extends in the longitudinal direction of the vehicle. That is, the CVT 4 is a so-called vertical CVT.

Input shaft 41 is formed into a hollow shaft and extends on the rotation axis of torque converter 3 . The front end of the input shaft 41 is inserted into the torque converter 3 and spline-fitted to the turbine hub 23 .

A central portion of the input shaft 41 in the axial direction is rotatably supported by the first case 11 via a ball bearing 45 .

A mechanical oil pump 46 is arranged on the rear side of the input shaft 41 (on the side opposite to the engine side). The oil pump 46 includes a pump case 47 and a pump cover 48 that is overlapped with the pump case 47. Pump case 47 and pump cover 48 are fastened together with a plurality of bolts and held in second case 12. A pump gear 49 is housed in a space surrounded by the pump case 47 and the pump cover 48.

The pump case 47 is arranged on the front side with respect to the pump cover 48. As shown in FIG. 2, a circular recess 51 that is recessed toward the rear is formed at the front end of the pump case 47. The rear end of the input shaft 41 is inserted into the recess 51 . A radial bearing 52 is interposed between the peripheral surface of the input shaft 41 and the inner peripheral surface of the recess 51, and a thrust bearing 53 is interposed between the end surface of the input shaft 41 and the bottom surface of the recess 51. . Thereby, the rear end of the input shaft 41 is rotatably supported by the pump case 47 via the radial bearing 52 and the thrust bearing 53.

As shown in FIG. 1, one end of a pump shaft 54 is connected to the pump gear 49 so as to be relatively non-rotatable. The pump shaft 54 passes through the center of the recess 51, projects forward from the pump case 47, and is inserted into the hollow portion of the input shaft 41 with a gap between it and the inner peripheral surface of the input shaft 41. The front end of the pump shaft 54 is inserted into the central portion of the front cover 21 of the torque converter 3 that bulges out to the front, and is coupled to 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, the pump shaft 54 and the pump gear 49 rotate together with the front cover 21, and oil pressure is generated from the oil pump 46.

Further, the input shaft 41 is rotatably supported by the first case 11 via a ball bearing 45, rotatably supported by the pump case 47 via a radial bearing 52 and a thrust bearing 53, and is rotatably supported by the pump case 47 via a radial bearing 52 and a thrust bearing 53. Since it is spline fitted to the hub 23, when the turbine runner 24 rotates, it rotates together with the turbine runner 24.

The continuously variable transmission mechanism 42 includes a primary shaft 61, a secondary shaft 62, a primary pulley 63, a secondary pulley 64, and a belt 65.

The primary shaft 61 extends parallel to the input shaft 41 with its axial center spaced apart to the lower right when viewed from the rear side of the vehicle with respect to the axial center of the input shaft 41 . The secondary shaft 62 extends parallel to the input shaft 41 with its axial center spaced apart to the upper left when viewed from the rear of the vehicle with respect to the axial center of the input shaft 41 . In this way, with respect to the input shaft 41, the primary shaft 61 and the secondary shaft 62 are arranged separately on the left and right sides. Thereby, the distance between the primary shaft 61 and the secondary shaft 62 in the vertical direction can be shortened, and the size of the CVT 4 in the vertical direction can be reduced. Therefore, even if the vehicle is a vehicle with a low-floor cabin such as a commercial vehicle, the transmission unit 1 can be mounted on the vehicle while ensuring the minimum ground clearance of the vehicle.

As shown in FIG. 1, the primary pulley 63 is arranged to face a primary fixed sheave 71 fixed to the primary shaft 61 and a belt 65 between the primary fixed sheave 71, and is movable in the axial direction of the primary shaft 61. and a primary movable sheave 72 supported so as not to be relatively rotatable. The primary movable sheave 72 is arranged on the front side with respect to the primary fixed sheave 71.

A cylinder 73 is provided on the side opposite to the primary fixed sheave 71 with respect to the primary movable sheave 72, that is, on the front side. The cylinder 73 has an inner peripheral end fixed to the primary shaft 61, extends from the primary shaft 61 in the shaft radial direction, and an outer peripheral end bent rearward. The outer peripheral end of the primary movable sheave 72 is in fluid-tight contact with the outer peripheral end of the cylinder 73 from inside in the rotational radial direction. A hydraulic chamber (piston chamber) 74 is formed between the primary movable sheave 72 and the cylinder 73.

The secondary pulley 64 is arranged to face a secondary fixed sheave 75 fixed to the secondary shaft 62 with the belt 65 interposed therebetween, and is supported by the secondary shaft 62 so as to be movable in the axial direction thereof and not to rotate relative to the secondary shaft 62. A secondary movable sheave 76 is provided. The secondary movable sheave 76 is disposed on the rear side with respect to the secondary fixed sheave 75, and the positional relationship between the secondary fixed sheave 75 and the secondary movable sheave 76 in the front-rear direction is such that the primary fixed sheave 71 of the primary pulley 63 and the primary The positional relationship with the movable sheave 72 is reversed.

A piston 77 is provided on the side opposite to the secondary fixed sheave 75 with respect to the secondary movable sheave 76, that is, on the rear side. The piston 77 has an inner peripheral end fixed to the secondary shaft 62 and extends from the secondary shaft 62 in the shaft radial direction. The outer peripheral end of the secondary movable sheave 76 extends rearward, and the outer peripheral end of the piston 77 fluid-tightly contacts the outer peripheral end of the secondary movable sheave 76 from inside in the rotational radial direction. A hydraulic chamber 78 is formed between the secondary movable sheave 76 and the piston 77.

The secondary fixed sheave 75 and the secondary movable sheave 76 of the secondary pulley 64 vertically overlap with a portion of the primary movable sheave 72 and the cylinder 73 (overlapping when viewed in the front-rear direction). Specifically, the outer peripheral end of the primary movable sheave 72 extends in the front-rear direction and its front end is bent outward in the rotational radial direction, and the secondary fixed sheave 75 extends at the outer peripheral end of the primary movable sheave 72. It faces a portion extending in the front-rear direction from the outside in the rotational radial direction, and faces a portion extending in the rotational radial direction at the outer peripheral end from the rear side.

In the continuously variable transmission mechanism 42, the hydraulic pressure supplied to each hydraulic chamber 74, 78 of the primary pulley 63 and secondary pulley 64 is controlled, and the groove width of the primary pulley 63 and secondary pulley 64 is changed. The gear ratio (the pulley ratio between the primary pulley 63 and the secondary pulley 64) is continuously and steplessly changed within a fixed gear ratio range.

Specifically, when the belt speed ratio is decreased, the hydraulic pressure supplied to the hydraulic chamber 74 of the primary pulley 63 is increased. As a result, the primary movable sheave 72 of the primary pulley 63 moves toward the primary fixed sheave 71, and the interval (groove width) between the primary fixed sheave 71 and the primary movable sheave 72 becomes smaller. Accordingly, the winding diameter of the belt 65 around the primary pulley 63 increases, and the interval (groove width) between the secondary fixed sheave 75 and the secondary movable sheave 76 of the secondary pulley 64 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 74 of the primary pulley 63 is lowered. As a result, the thrust force of the secondary pulley 64 with respect to the belt 65 becomes larger than the thrust force of the primary pulley 63 with respect to the belt 65, the distance between the secondary fixed sheave 75 and the secondary movable sheave 76 of the secondary pulley 64 becomes smaller, and the primary fixed sheave 71 and the primary movable sheave 72 becomes larger. As a result, the belt transmission ratio increases.

A bias spring 79 is provided in the hydraulic chamber 78 of the secondary pulley 64. The bias spring 79 has one end in elastic contact with the secondary movable sheave 76 and the other end in elastic contact with the piston 77. The elastic force of the bias spring 79 urges the secondary movable sheave 76 and the piston 77 in a direction away from each other. A biasing force is applied to the secondary movable sheave 76 by the hydraulic pressure in the hydraulic chamber 78 and a bias spring 79, and a corresponding pinching pressure is applied to the belt 65.

Further, the primary shaft 61 is configured to be divided into a first primary shaft 81 and a second primary shaft 82. The first primary shaft 81 is arranged in front of the second primary shaft 82. The primary pulley 63 is supported by the second primary shaft 82. At the rear end of the first primary shaft 81, a connection recess 83 having a substantially cylindrical space recessed from the rear end surface is formed. The front end of the second primary shaft 82 is inserted into the connection recess 83 , and within the connection recess 83 , the outer peripheral surface of the second primary shaft 82 is spline-fitted with the inner peripheral surface of the connection recess 83 . There is. The front end of the first primary shaft 81 is rotatably supported by the first case 11 via a bearing 84. A front end of the second primary shaft 82 is rotatably supported by the second case 12 via a bearing 85. An adapter 86 fixedly held by the second case 12 is arranged on the rear side of the primary pulley 63, and the rear end of the second primary shaft 82 is rotated by the adapter 86 via a bearing 87. Possibly supported.

As shown in FIG. 2, an input shaft gear 91 is integrally formed on the input shaft 41 at a portion adjacent to the rear side of a portion into which the inner race of the ball bearing 45 is fitted. Correspondingly, a primary input gear 92 is supported by the first primary shaft 81 via a needle bearing 93 so as to be relatively rotatable. The primary input gear 92 meshes with the input shaft gear 91 and has a larger gear diameter than the input shaft gear 91.

A forward clutch 94 that allows/prohibits rotation of the primary input gear 92 with respect to the first primary shaft 81 by utilizing the space between the input shaft gear 91 and the primary input gear 92 that mesh with each other and the pump case 47 of the oil pump 46. is provided. A portion of the forward clutch 94 overlaps the oil pump 46 in the rotational radial direction (overlapping when viewed in the rotational axis direction). The forward clutch 94 includes a clutch drum 95, a clutch hub 96, a clutch piston 97, and a canceller 98.

The clutch drum 95 has an inner peripheral end fixed to the first primary shaft 81, extends from the first primary shaft 81 in the rotational radial direction, and an outer peripheral end bent and extends toward the primary input gear 92, that is, toward the front. A plurality of clutch plates 101 are held at the outer peripheral end of the clutch drum 95 in a row at intervals in the front-rear direction.

Clutch hub 96 is integrally formed with primary input gear 92. The clutch hub 96 has a cylindrical shape extending rearward from the primary input gear 92, and faces the outer circumferential end of the clutch drum 95 from the inner side in the rotational radial direction at a distance. A plurality of clutch disks 102 are held on the clutch hub 96 at intervals in the front-rear direction. Clutch plates 101 and clutch discs 102 are arranged alternately in the central axis direction.

The clutch piston 97 is provided between the clutch drum 95 and the clutch hub 96 so as to be movable in the axial direction of the first primary shaft 81, that is, in the front-back direction. The clutch piston 97 extends from the first primary shaft 81 to the outside in the radial direction of the first primary shaft 81, and has an outer peripheral end bent forward. The tip of the outer peripheral end of the clutch piston 97 contacts the clutch plate 101 . Further, the clutch piston 97 is in fluid-tight contact with the clutch drum 95, and a hydraulic chamber 103 is formed between the clutch drum 95 and the clutch piston 97 to which hydraulic pressure acting on the clutch piston 97 is supplied. ing.

A canceller 98 is provided between the clutch hub 96 and the clutch piston 97. An inner peripheral end of the canceller 98 is fixed to the first primary shaft 81. The outer peripheral end of the canceller 98 is in liquid-tight contact with the clutch piston 97. Thereby, a canceller chamber 104 is formed between the clutch piston 97 and the canceller 98. A return spring 105 is provided in the canceller chamber 104, and the clutch piston 97 and the canceller 98 are elastically urged in a direction away from each other by the urging force of the return spring 105.

The clutch piston 97 moves toward the clutch plate 101 by the hydraulic pressure supplied to the hydraulic chamber 103 and presses the clutch plate 101. This pressure brings the clutch plate 101 and clutch disc 102 into pressure contact, and the forward clutch 94 is engaged. By engaging the forward clutch 94, rotation of the primary input gear 92 with respect to the first primary shaft 81 is prohibited, and when the primary input gear 92 rotates, the first primary shaft 81 rotates together with the primary input gear 92. When the hydraulic pressure is released from the engaged state of the forward clutch 94, the clutch piston 97 is separated from the clutch plate 101 due to the urging force of the return spring 105 interposed between the clutch piston 97 and the canceller 98. As a result, the pressure contact between clutch disc 102 and clutch plate 101 is released, and forward clutch 94 is released. By releasing the forward clutch 94, rotation of the primary input gear 92 with respect to the first primary shaft 81 is allowed, and even if the primary input gear 92 rotates, the rotation is not transmitted to the first primary shaft 81.

The secondary shaft 62 is divided into a first secondary shaft 111 and a second secondary shaft 112. The first secondary shaft 111 is arranged in front of the second secondary shaft 112. Secondary pulley 64 is supported by second secondary shaft 112. A circular connection recess 113 is formed at the rear end of the first secondary shaft 111 . The front end of the second secondary shaft 112 is inserted into the connection recess 113 , and within the connection recess 113 , the outer peripheral surface of the second secondary shaft 112 is spline-fitted with the inner peripheral surface of the connection recess 113 . The first secondary shaft 111 is the same component as the first primary shaft 81, as can be understood by comparing it with the first primary shaft 81. By using the first primary shaft 81 and the first secondary shaft 111 in common, the number of types of parts constituting the transmission unit 1 (CVT 4) can be reduced, and the manufacturing cost of the transmission unit 1 can be reduced. A front end of the first secondary shaft 111 is rotatably supported by the first case 11 via a bearing 114. A front end of the second secondary shaft 112 is rotatably supported by the second case 12 via a bearing 115. A rear end of the second secondary shaft 112 is rotatably supported by the third case 13 via a bearing 116.

A secondary input gear 121 is supported by the second secondary shaft 112 on the rear side of the bearing 114 via a needle bearing 122 so as to be relatively rotatable.

A reverse clutch 123 is provided that utilizes the space between the secondary input gear 121 and the pump case 47 of the oil pump 46 to allow/prohibit rotation of the secondary input gear 121 with respect to the first secondary shaft 111. A portion of the reverse clutch 123 overlaps with the oil pump 46 in the rotational radial direction (overlapping when viewed in the rotational axis direction). The reverse clutch 123 includes a clutch drum 124, a clutch hub 125, a clutch piston 126, and a canceller 127.

The clutch drum 124 has an inner peripheral end fixed to the first secondary shaft 111, extends from the first secondary shaft 111 in the shaft radial direction, and an outer peripheral end bent and extends toward the secondary input gear 121 side, that is, toward the front side. A plurality of clutch plates 131 are held at the outer peripheral end of the clutch drum 124 in a row at intervals in the front-rear direction.

Clutch hub 125 is formed integrally with secondary input gear 121. The clutch hub 125 has a cylindrical shape extending rearward from the secondary input gear 121, and faces the outer peripheral end of the clutch drum 124 from the inner side in the rotational radial direction with a space therebetween. A plurality of clutch disks 132 are held by the clutch hub 125 at intervals in the front-rear direction. Clutch plates 131 and clutch discs 132 are arranged alternately in the central axis direction. The number of clutch plates 131 and clutch discs 132 is greater than the number of clutch plates 101 and clutch discs 102 of forward clutch 94.

The clutch piston 126 is provided between the clutch drum 124 and the clutch hub 125 so as to be movable in the axial direction of the first secondary shaft 111, that is, in the front-back direction. The clutch piston 126 extends from the first secondary shaft 111 to the outside in the radial direction of the first secondary shaft 111, and has an outer peripheral end bent forward. The tip of the outer peripheral end of the clutch piston 126 contacts the clutch plate 131 . Further, the clutch piston 126 is in liquid-tight contact with the clutch drum 124, and a hydraulic chamber 133 is formed between the clutch drum 124 and the clutch piston 126 to which hydraulic pressure acting on the clutch piston 126 is supplied. ing.

Canceller 127 is provided between clutch hub 125 and clutch piston 126. An inner peripheral end of the canceller 127 is fixed to the first secondary shaft 111. The outer peripheral end of the canceller 127 is in liquid-tight contact with the clutch piston 126. As a result, a canceller chamber 134 is formed between the clutch piston 126 and the canceller 127. A return spring 135 is provided in the canceller chamber 134, and the clutch piston 126 and the canceller 127 are elastically urged in a direction away from each other by the urging force of the return spring 135.

The clutch piston 126 moves toward the clutch plate 131 by the hydraulic pressure supplied to the hydraulic chamber 133 and presses the clutch plate 131. This pressure brings the clutch plate 131 and clutch disc 132 into pressure contact, and the reverse clutch 123 is engaged. By engaging the reverse clutch 123, rotation of the secondary input gear 121 with respect to the first secondary shaft 111 is prohibited, and when the secondary input gear 121 rotates, the first secondary shaft 111 rotates together with the secondary input gear 121. When the hydraulic pressure is released from the engaged state of the reverse clutch 123, the clutch piston 126 is separated from the clutch plate 131 due to the urging force of the return spring 135 interposed between the clutch piston 126 and the canceller 127. As a result, the pressure contact between clutch disc 132 and clutch plate 131 is released, and reverse clutch 123 is released. By releasing the reverse clutch 123, rotation of the secondary input gear 121 with respect to the first secondary shaft 111 is allowed, and even if the secondary input gear 121 rotates, the rotation is not transmitted to the first secondary shaft 111.

The reverse transmission mechanism 43 is a mechanism that transmits the power (rotation) of the input shaft 41 to the secondary shaft 62 (first secondary shaft 111) without passing through the continuously variable transmission mechanism 42. Reverse transmission mechanism 43 includes a reverse idler shaft 141, a first reverse gear 142, and a second reverse gear 143.

The reverse idler shaft 141 extends in the front-rear direction parallel to the input shaft 41. A front end of the reverse idler shaft 141 is rotatably supported by the first case 11 via a bearing 144. A rear end of the reverse idler shaft 141 is rotatably supported by the second case 12 via a bearing 145.

The first reverse gear 142 is formed integrally with the reverse idler shaft 141. The first reverse gear 142 meshes with the input shaft gear 91 and has a larger gear diameter than the input shaft gear 91. The second reverse gear 143 is formed integrally with the reverse idler shaft 141 on the rear side of the first reverse gear 142 . The second reverse gear 143 meshes with the secondary input gear 121 and has a smaller gear diameter than the secondary input gear 121.

The output shaft 44 is disposed on the same axis as the input shaft 41 with a space behind the input shaft 41 . In other words, the input shaft 41 and the output shaft 44 are arranged at intervals in the front-rear direction, respectively, so as to have a common axis extending vertically along the front-rear direction of the vehicle.

A front end of the output shaft 44 is rotatably supported by an adapter 86 via a needle bearing 146. Further, the output shaft 44 is rotatably supported by the third case 13 via the bearing 147, with an inner ring of a bearing 147 being fitted onto a portion spaced rearward from the portion supported by the needle bearing 146. has been done.

An output shaft gear 148 is integrally formed on the output shaft 44 between a portion supported by a needle bearing 146 and a portion supported by a bearing 147. Correspondingly, a secondary output gear 149 is supported on the secondary shaft 62 (second secondary shaft 112) so as to be relatively non-rotatable by spline fitting adjacent to the rear side of the piston 77 of the secondary pulley 64. . Secondary output gear 149 meshes with output shaft gear 148 .

<Power transmission path>
FIG. 3 is a skeleton diagram showing the power transmission path in the CVT 4 together with the configuration of the CVT 4.

When the vehicle moves forward, forward clutch 94 is engaged and reverse clutch 123 is released. Power input from the engine to input shaft 41 via torque converter 3 is transmitted from input shaft gear 91 to primary shaft 61 via primary input gear 92 through engagement of forward clutch 94 . On the other hand, even if the power input to the input shaft 41 is transmitted from the input shaft gear 91 to the secondary input gear 121 and the secondary input gear 121 rotates, the release of the reverse clutch 123 causes the secondary input gear 121 to rotate to the secondary shaft 62. (The first secondary shaft 111) rotates idly, and no power is transmitted to the secondary shaft 62.

The power transmitted to the primary shaft 61 is transmitted to the secondary shaft 62 after being changed in speed at a belt speed ratio according to the pulley ratio between the primary pulley 63 and the secondary pulley 64 . The power transmitted to the secondary shaft 62 is transmitted from the secondary output gear 149 to the output shaft 44 via the output shaft gear 148, is output from the output shaft 44 to a propeller shaft (not shown), and is transmitted from the propeller shaft to the output shaft 44. It is transmitted to the left and right rear wheels via the rear differential gear (rear differential) and drive shaft.

Since the gear diameter of primary input gear 92 is larger than the gear diameter of input shaft gear 91, the power of input shaft 41 is reduced in speed by input shaft gear 91 and primary input gear 92, and then transmitted to primary shaft 61. Further, since the gear diameter of the output shaft gear 148 is larger than the gear diameter of the secondary output gear 149, the power of the secondary shaft 62 is reduced by the secondary output gear 149 and the output shaft gear 148, and is transmitted to the output shaft 44. .

When the vehicle is traveling backwards, forward clutch 94 is released and reverse clutch 123 is engaged. Power input from the engine to the input shaft 41 via the torque converter 3 is transmitted from the input shaft gear 91 to the secondary shaft 62 via the reverse transmission mechanism 43 and the secondary input gear 121 by engagement of the reverse clutch 123. . At this time, the secondary shaft 62 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 shaft gear 91 to the primary input gear 92 and the primary input gear 92 rotates, the release of the forward clutch 94 causes the primary input gear 92 to move toward the primary shaft 61. (first primary shaft 81) and no power is transmitted to the primary shaft 61.

The power transmitted to the secondary shaft 62 is transmitted from the secondary output gear 149 to the output shaft 44 via the output shaft gear 148, and is output from the output shaft 44 to the propeller shaft, and is transmitted from the propeller shaft to the rear differential gear and drive shaft. is transmitted to the left and right rear wheels.

The gear diameter of the first reverse gear 142 of the reverse transmission mechanism 43 is larger than the gear diameter of the input shaft gear 91, and the gear diameter of the secondary input gear 121 is larger than the gear diameter of the second reverse gear 143 of the reverse transmission mechanism 43. The power of the input shaft 41 is reduced in speed by the input shaft gear 91, the reverse transmission mechanism 43, and the secondary input gear 121, and is transmitted to the secondary shaft 62. Further, since the gear diameter of the output shaft gear 148 is larger than the gear diameter of the secondary output gear 149, the power of the secondary shaft 62 is reduced by the secondary output gear 149 and the output shaft gear 148, and is transmitted to the output shaft 44. .

<Main part configuration>
FIG. 4 is an enlarged cross-sectional view showing the configuration near the rear end of the input shaft 41. As shown in FIG.

The radial bearing 52 is, for example, a radial needle bearing (radial roller bearing), and has a configuration in which a plurality of needle rollers 201 are arranged in the axial circumferential direction (rotational circumferential direction) and each extends in the axial longitudinal direction. ing. Each needle roller 201 is rotatably held by a cage 202, and its peripheral surface is in contact with the outer peripheral surface of the input shaft 41. The end portion 203 of the input shaft 41 that the needle rollers 201 come into contact with is formed to have a larger diameter by bulging in the shaft radial direction with respect to the front portion thereof.

A portion of the radial bearing 52 overlaps (overlaps) the clutch drum 95 of the forward clutch 94 in the axial direction (rotational axis direction). Furthermore, the radial bearing 52 entirely overlaps (overlaps) the clutch drum 124 of the reverse clutch 123 in the axial direction.

A space 204 is created around the input shaft 41 on the front side of the radial bearing 52. The recess 51 of the pump case 47 is open toward the space 204 thereof.

A plurality of oil discharge holes 205 are formed in the clutch drum 95 of the forward clutch 94 at intervals in the circumferential direction for discharging oil from the inside of the clutch drum 95 to the outside. A portion other than a portion on the rear side faces the space 204 in the axial and radial direction. Further, in the clutch drum 124 of the reverse clutch 123, a plurality of oil discharge holes 206 for discharging oil from the inside to the outside of the clutch drum 124 are formed at intervals in the circumferential direction, and each oil discharge hole 206 The entire space 204 faces the space 204 in the axial and radial direction.

The thrust bearing 53 has a configuration in which a plurality of needle rollers 213 are arranged in the circumferential direction between the first bearing ring 211 and the second bearing ring 212 so as to extend in the radial direction. . Each needle roller 213 is rotatably held by a retainer 214. The first bearing ring 211 is in contact with the rear end surface of the input shaft 41 , and the second bearing ring 212 is in contact with the bottom surface of the recess 51 of the pump case 47 .

The outer diameter of the thrust bearing 53 is larger than the inner diameter of the radial bearing 52. Further, the end of the outer circumferential side of the needle rollers 213 of the thrust bearing 53 is located closer to the shaft center than the inner circumference of the radial bearing 52.

<Effect>
As described above, the ball bearing 45 is used to support the front side (engine side) of the input shaft 41, and the radial bearing 52 is used to support the rear side (opposite the engine side) of the input shaft 41. By employing the ball bearing 45, the input shaft 41 can be easily positioned in the axial direction.

On the other hand, by adopting the radial bearing 52, the rear bearing portion of the input shaft 41, that is, the portion including the radial bearing 52, can be made smaller in the shaft radial direction, and the rear bearing portion can be arranged in a space-saving manner. I can do it.

Furthermore, since the thrust bearing 53 is disposed in contact with the rear end surface of the input shaft 41, mechanical loss due to rotation of the input shaft 41 can be reduced.

Furthermore, since the outer diameter of the thrust bearing 53 is larger than the inner diameter of the radial bearing 52, the length of the needle rollers 213 provided in the thrust bearing 53 can be ensured long; The diameter can be kept small. As a result, the thickness (dimension in the axial direction) of the thrust bearing 53 can be kept small, and the size of the bearing portion on the rear side of the input shaft 41 can also be reduced in the axial direction.

Furthermore, since the outer circumferential end of the needle rollers 213 of the thrust bearing 53 is located closer to the center than the inner circumference of the radial bearing 52, the force input from the input shaft 41 is received over the entire length of the needle rollers 213. be able to. Therefore, it is possible to suppress the thrust bearing 53 from being inclined with respect to the shaft length direction and the shaft radial direction and contacting the end surface of the input shaft 41, and the durability (life) of the thrust bearing 53 can be improved. Mechanical loss due to rotation of the shaft 41 can be reduced favorably.

Further, the forward clutch 94, the reverse clutch 123, and the radial bearing 52 are arranged to overlap in the axial direction. Thereby, the transmission unit 1 (CVT 4) can be made smaller in the axial direction compared to a configuration in which the radial bearing 52, the forward clutch 94, and the reverse clutch 123 are arranged apart from each other in the axial direction.

Furthermore, a space 204 is formed around the input shaft 41 on the front side of the radial bearing 52, and the forward clutch 94 and the reverse clutch 123 each have an oil discharge hole at a position facing the space 204 in the shaft radial direction. 205 and 206. Therefore, the radial bearing 52 can be lubricated by the oil discharged from these oil discharge holes 205 and 206.

<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 above-described embodiment, a CVT 4 for vertical installation was used as an example of a transmission, but the present invention can also be applied to a transmission that is installed horizontally so that the input shaft extends in the left-right direction of the vehicle. can.

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

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

1: Transmission unit (transmission)
4: CVT (transmission)
41: Input shaft 45: Ball bearing 52: Radial bearing 53: Thrust bearing

Claims (2)

A transmission mounted on a vehicle,
an input shaft extending to a first side that is a drive source side and a second side opposite thereto, and into which power from the drive source is input;
a ball bearing externally fitted on the input shaft;
a radial bearing disposed in contact with a circumferential surface of the input shaft at a position on the second side with respect to the ball bearing;
a thrust bearing disposed in contact with an end surface on the second side of the input shaft;
a primary shaft extending parallel to the input shaft;
a secondary axis extending parallel to the input axis;
a primary input gear rotatably supported by the primary shaft;
a secondary input gear rotatably supported by the secondary shaft;
a first clutch that allows/prohibits rotation of the primary input gear with respect to the primary shaft;
a second clutch that allows/prohibits rotation of the secondary input gear with respect to the secondary shaft,
In the radial bearing and the thrust bearing, the outer diameter of the thrust bearing is larger than the inner diameter of the radial bearing, and the outer circumferential end of the roller provided in the thrust bearing is closer to the axial center than the inner circumference of the radial bearing. Designed to be located on the side
The radial bearing is arranged to overlap the first clutch and the second clutch in the axial direction . A space is formed around the input shaft on the first side of the radial bearing,
The transmission according to claim 1, wherein the first clutch and the second clutch each have an oil discharge hole at a position facing the space in the radial direction of the shaft.

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