JP2021024336A - transmission - Google Patents

Abstract

To provide a transmission which can be reduced in a vertical size.SOLUTION: In a CVT4, a primary shaft 61 and a secondary shaft 62 are arranged separately on the left and right with respect to an input shaft 41. The primary shaft 61 and the secondary shaft 62 are respectively off-set on one side and the other side in the vertical direction with respect to the input shaft 41. Specifically, in the CVT4, the primary shaft 61 is located at a position below the input shaft 41, and the secondary shaft 62 is located at a position above the input shaft 41. A valve body 151 having a relatively large vertical size is located below a secondary pulley 64 (secondary shaft 62) positioned at a relatively high position, and a strainer 171 having a relatively small vertical size is located below a primary pulley 63 (primary shaft 61) positioned at a relatively low position.SELECTED DRAWING: Figure 4

Description

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

In a vehicle equipped with an engine as a driving source for traveling, the power of the engine is transmitted to the drive wheels via a transmission. There are two types of engine mounting methods: vertical installation in which the crankshaft is oriented vertically with respect to the front-rear direction of the vehicle body, and horizontal installation in which the crankshaft is oriented horizontally. In vehicles that adopt the FF (Front-engine Front-wheel-drive) layout, for example, the engine is installed horizontally to increase the cabin length by reducing the size of the engine compartment in the front-rear direction. Often done. On the other hand, in vehicles that adopt the FR (Front-engine Rear-wheel-drive) layout, the engine is installed vertically because it is easy to transmit power to the rear wheels, which are the driving wheels. It may be installed.

A CVT (Continuously Variable Transmission) for vertical installation has already been provided as a transmission for vehicles in which the engine is installed vertically. The CVT for vertical installation is arranged so that the input shaft into which the power of the engine is input is vertically oriented with respect to the front-rear direction of the vehicle body.

In an example of a CVT for vertical installation, the input axis and the primary axis are arranged on the same axis line, and the secondary axis is arranged below the primary axis. Further, in the CVT, a valve body for controlling the supply of oil to each part is arranged at the bottom of the case forming the outer shell, and an oil pan is bolted from the lower side of the valve body to the case. A strainer for sucking up the oil stored in the oil pan and supplying it to the valve body is arranged between the valve body and the oil pan.

Japanese Unexamined Patent Publication No. 2012-192855

Generally, the valve body, strainer and oil pan are arranged one above the other below the secondary shaft. However, in that layout, the size of the transmission in the vertical direction becomes too large. Therefore, a small vehicle with an FR layout in which the engine is mounted vertically, and a new vehicle under development by the inventors of the present application cannot be equipped with a transmission adopting a conventional general layout.

An object of the present invention is to provide a transmission capable of reducing the size in the vertical direction.

In order to achieve the above object, the transmission according to the present invention has a case constituting the outer shell, an input shaft into which the power of the drive source is input, and a primary shaft and a secondary shaft extending in parallel with the input shaft, respectively. Then, a stepless transmission mechanism that shifts and transmits power from the primary shaft to the secondary shaft, a valve body that supplies oil to the stepless transmission mechanism, and a strainer that sucks up the oil accumulated at the bottom of the case and supplies it to the valve body. The primary axis and the secondary axis are divided into left and right with respect to the input axis when viewed from the axial direction of the input axis, and one is arranged so as to be located higher than the other, and the valve body is the primary axis. And one below the secondary axis, the strainer is located below the other of the primary and secondary axes.

According to this configuration, the primary axis and the secondary axis are separately arranged on the left and right sides of the input axis when viewed from the axial direction of the input axis. As a result, the distance between the primary shaft and the secondary shaft in the vertical direction can be shortened. As a result, the vertical size of the transmission can be reduced.

One of the primary shaft and the secondary shaft is located higher than the other, and a valve body having a relatively large vertical size is arranged on the lower side of the one, and on the lower side of the other. , A strainer with a relatively small vertical size is arranged. With this layout, the size of the transmission in the vertical direction can be further reduced.

According to the present invention, the size of the transmission in the vertical direction can be reduced. By reducing the size of the transmission in the vertical direction, it is possible to mount the transmission on a vehicle with a low floor, such as a commercial vehicle, while ensuring the minimum ground clearance of the vehicle. Can be.

It is sectional drawing which shows the structure of the transmission unit which concerns on one Embodiment of this invention. It is sectional drawing which shows by pulling out a part of the speed change unit from FIG. It is the figure which looked at the inside of the 2nd case of a transmission unit from the rear side (the side opposite to the engine side). It is a figure which shows the structure in the 2nd case, and is the figure which looked at the structure in the 2nd case from the rear side. It is the figure which looked at the part including the 2nd case in a transmission unit from the lower side. It is the figure which looked at the strainer from the front side. It is a skeleton diagram which shows the power transmission path in a CVT together with the structure of a CVT.

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 the configuration of a transmission unit 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a part of the transmission unit 1 extracted from FIG. 1 and enlarged. In the cross-sectional views after FIG. 1, the addition of hatching representing the cross section is omitted.

The speed change unit 1 is a unit mounted on a vehicle to change the power generated by an engine (E / G) as a driving source for traveling. 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 front-rear direction of the vehicle body. The transmission unit 1 includes a torque converter 3 and a CVT 4 in a unit case 2 forming an outer shell.

In the following, the case where the engine is a 3-cylinder 4-stroke engine will be taken up, but the number of cylinders of the engine is not limited to 3 cylinders, and may be 4 cylinders or more, or 2 cylinders or less. Further, the number of strokes of the engine is not limited to 4 strokes and may be 2 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 two cases 12 and the third case 13 are integrated by being fastened with bolts 14. The torque converter 3 is housed in the first case 11, and the CVT 4 is housed in the second case 12 and the 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 rotation axis extending in the front-rear direction of the vehicle (vehicle body), and the outer peripheral end thereof is the rear side opposite to the engine side (the continuously variable transmission mechanism 42 side described later). It has a bent shape. The central portion of the front cover 21 bulges toward the front side. The crankshaft of the engine is connected to this bulging portion so that it cannot rotate relative to each other.

The pump impeller 22 is arranged behind the front cover 21. The outer peripheral end of the pump impeller 22 is connected to the outer peripheral end of the front cover 21 and is provided so as to be rotatable integrally with the front cover 21 around the rotation axis. A plurality of blades 27 are arranged radially on the inner surface of the pump impeller 22.

The turbine hub 23 is arranged between the front cover 21 and the pump impeller 22.

The turbine runner 24 is fixed to the turbine hub 23. A plurality of blades 28 are arranged in a radial pattern 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, and its inner peripheral end is fitted onto the turbine hub 23 and is located between the front cover 21 and the turbine runner 24. When the oil pressure of 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 of the release side oil chamber 34 on the front cover 21 side, the lockup piston 31 moves to the front cover due to the differential pressure. Move to the 21 side. Then, when the lockup piston 31 is pressed against the front cover 21, the pump impeller 22 and the turbine runner 24 are directly connected (lockup on). On the contrary, when the oil pressure of the release side oil chamber 34 is higher than the oil pressure of the engagement side oil chamber 33, the lockup piston 31 moves to the turbine runner 24 side due to the differential pressure. When the lockup piston 31 is separated from the front cover 21, the direct connection between the pump impeller 22 and the turbine runner 24 is released (lockup off).

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

The stator 26 is arranged between the pump impeller 22 and the turbine runner 24.

When the pump impeller 22 is rotated by the engine torque in the lock-up-off state, an oil flow from the pump impeller 22 to the turbine runner 24 is generated. This oil flow is received by the blade 28 of the turbine runner 24, and the turbine runner 24 rotates. At this time, the amplification action 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 so that the input shaft 41 extends vertically in the front-rear direction of the vehicle. That is, the CVT 4 is a so-called vertical CVT.

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

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

A mechanical oil pump 46 is arranged on the rear side (opposite side to the engine side) of the input shaft 41. The oil pump 46 includes a pump case 47 and a pump cover 48 that is superposed on the pump case 47. The pump case 47 and the pump cover 48 are fastened by a plurality of bolts and held in the 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 recessed on the rear side 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 needle 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. .. As a result, the rear end of the input shaft 41 is rotatably supported by the pump case 47 via the needle bearing 52 and the thrust bearing 53.

As shown in FIG. 1, one end of the pump shaft 54 is connected to the pump gear 49 so as not to rotate relative to each other. The pump shaft 54 penetrates the central portion of the recess 51, protrudes 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 a portion of the torque converter 3 that bulges toward the front of the center of the front cover 21, and is coupled to the front cover 21 so as not to rotate relative to each other. 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 are rotated integrally with the front cover 21, and oil is generated from the oil pump 46.

Further, the input shaft 41 is rotatably supported by the first case 11 via the bearing 45 and rotatably supported by the pump case 47 via the needle bearing 52 and the thrust bearing 53, and is rotatably supported by the turbine hub of the torque converter 3. When the turbine runner 24 rotates due to the spline fitting with the 23, the turbine runner 24 rotates integrally 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.

FIG. 3 is a view of the inside of the second case 12 as viewed from the rear side. Note that FIG. 1 is a cross-sectional view when the transmission unit 1 is cut along the cutting line surface AA shown in FIG.

The primary shaft 61 is arranged at a position where its axis is separated from the center of the input shaft 41 to the lower right when viewed from the rear side of the vehicle, and extends parallel to the input shaft 41. The distance between the axes of the input shaft 41 and the primary shaft 61, in other words, the distance in the axial direction (rotational radial direction) between the axis of the input shaft 41 and the axis of the primary shaft 61 is determined by the turbine runner of the torque converter 3. It is shorter than the turning radius of 24.

The secondary shaft 62 is arranged at a position where its axis is separated from the center of the input shaft 41 toward the upper left when viewed from the rear side of the vehicle, and extends parallel to the input shaft 41. The distance between the axes of the input shaft 41 and the secondary shaft 62, in other words, the distance in the axial direction between the axis of the input shaft 41 and the axis of the secondary shaft 62, is the axis of the input shaft 41 and the axis of the primary shaft 61. It is equal to the axial distance between and, and shorter than the turning radius of the turbine runner 24 of the torque converter 3.

In this way, the primary shaft 61 and the secondary shaft 62 are separately arranged on the left and right sides with respect to the input shaft 41. As a result, 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. In the speed change unit 1, the vertical positions of the primary shaft 61 and the secondary shaft 62 are set between the uppermost position and the lowest position of the torque converter 3, and the primary shaft 61 and the secondary shaft 62 are the turbine runner 24 of the torque converter 3. The size of the continuously variable transmission mechanism 42 in the vertical direction has been reduced to the extent that it faces the front-rear direction. Therefore, even in a vehicle such as a commercial vehicle having a low floor, it is possible to mount the speed change unit 1 on the vehicle while ensuring the minimum ground clearance of the vehicle.

The primary shaft 61 and the secondary shaft 62 are offset to one side and the other side in the vertical direction with respect to the input shaft 41, respectively. Specifically, in the CVT 4, the primary shaft 61 is arranged at a position lower than the input shaft 41, and the secondary shaft 62 is arranged at a position above the input shaft 41. As a result, the second case 12 has a portion recessed toward the primary shaft 61 with respect to the rear end portion (a portion facing the primary pulley 63 in the radial direction of rotation) at a position on the upper right side of the primary shaft 61. There is. A starter ST for starting the engine is arranged in the space provided by the recessed portion.

As shown in FIG. 1, the primary pulley 63 is arranged to face the primary fixed sheave 71 fixed to the primary shaft 61 and the primary fixed sheave 71 with the belt 65 sandwiched between them, and can move to the primary shaft 61 in the axial direction thereof. It also has a primary movable sheave 72 that is supported so that it cannot rotate relative to each other. 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 side with respect to the primary movable sheave 72, that is, on the front side. The inner peripheral end of the cylinder 73 is fixed to the primary shaft 61, extends in the axial direction from the primary shaft 61, and the outer peripheral end portion bends and extends rearward. The outer peripheral end of the primary movable sheave 72 is in liquidtight contact with the outer peripheral end of the cylinder 73 from the inside in the radial direction of rotation. 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 the secondary fixed sheave 75 fixed to the secondary shaft 62 and the secondary fixed sheave 75 with the belt 65 interposed therebetween, and is supported by the secondary shaft 62 so as to be movable in the axial direction and non-relatively rotatable. It is equipped with a secondary movable sheave 76. The secondary movable sheave 76 is arranged 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 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, that is, on the rear side with respect to the secondary movable sheave 76. The inner peripheral end of the piston 77 is fixed to the secondary shaft 62 and extends from the secondary shaft 62 in the axial direction. The outer peripheral end of the secondary movable sheave 76 extends to the rear side, and the outer peripheral end of the piston 77 is in liquidtight contact with the outer peripheral end of the secondary movable sheave 76 from the inside in the radial direction of rotation. The space between the secondary movable sheave 76 and the piston 77 is formed as a hydraulic chamber 78.

The secondary fixed sheave 75 and the secondary movable sheave 76 of the secondary pulley 64 overlap with a part of the primary movable sheave 72 and the cylinder 73 in the vertical direction (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 radial direction of rotation, and the secondary fixed sheave 75 is located at the outer peripheral end of the primary movable sheave 72. It faces the portion extending in the front-rear direction from the outside in the radial direction of rotation, and faces the portion extending in the radial direction of rotation at the outer peripheral end portion from the rear side.

In the continuously variable transmission mechanism 42, the hydraulic pressure supplied to the hydraulic chambers 74 and 78 of the primary pulley 63 and the secondary pulley 64 is controlled, and the groove widths of the primary pulley 63 and the secondary pulley 64 are changed to change the belt. The gear ratio (pulley ratio between the primary pulley 63 and the secondary pulley 64) is continuously and steplessly changed within a constant gear ratio range.

Specifically, when the belt gear ratio is reduced, the oil supply 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 distance (groove width) between the primary fixed sheave 71 and the primary movable sheave 72 becomes smaller. Along with this, the winding diameter of the belt 65 with respect to the primary pulley 63 becomes large, and the distance (groove width) between the secondary fixed sheave 75 and the secondary movable sheave 76 of the secondary pulley 64 becomes large. As a result, the belt gear ratio becomes smaller.

When the belt gear ratio is increased, the oil supply to the hydraulic chamber 74 of the primary pulley 63 is reduced. As a result, the thrust of the secondary pulley 64 with respect to the belt 65 becomes larger than the thrust of the primary pulley 63 with respect to the belt 65, the distance between the secondary fixed sheave 75 of the secondary pulley 64 and the secondary movable sheave 76 becomes smaller, and the primary fixed sheave 71 The distance between the and the primary movable sheave 72 becomes large. As a result, the belt gear ratio becomes large.

A bias spring 79 is provided in the hydraulic chamber 78 of the secondary pulley 64. One end of the bias spring 79 elastically contacts the secondary movable sheave 76, and the other end elastically contacts the piston 77. The elastic force of the bias spring 79 urges the secondary movable sheave 76 and the piston 77 in a direction in which they are separated from each other. The secondary movable sheave 76 is subjected to the hydraulic pressure in the hydraulic chamber 68 and the urging force by the bias spring 79, and the belt 65 is subjected to the corresponding pinching pressure.

Further, the primary shaft 61 is divided into a first primary shaft 81 and a second primary shaft 82. The first primary shaft 81 is arranged on the front side of the second primary shaft 82. The primary pulley 63 is supported by the second primary shaft 82. A circular connection recess 83 is formed at the rear end of the first primary shaft 81. The front end of the second primary shaft 82 is inserted into the connection recess 83, and the outer peripheral surface of the second primary shaft 82 is spline-fitted with the inner peripheral surface of the connection recess 83 in the connection recess 83. .. The front end of the first primary shaft 81 is rotatably supported by the first case 11 via a bearing 84. The 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 in 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 rotates to the adapter 86 via a bearing 87. It is supported as much as possible.

As shown in FIG. 2, the input shaft 41 is integrally formed with an input shaft gear 91 in a portion adjacent to the rear side of a portion in which the inner ring (inner race) of the bearing 45 is fitted. Correspondingly, the primary input gear 92 is supported on the first primary shaft 81 so as to be relatively rotatable via the needle bearing 93. 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 part of the forward clutch 94 overlaps with the oil pump 46 in the rotational radial direction (overlaps 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 inner peripheral end of the clutch drum 95 is fixed to the first primary shaft 81, extends in the radial direction from the first primary shaft 81, and the outer peripheral end portion bends and extends toward the primary input gear 92, that is, the front side. A plurality of clutch plates 101 are held side by side at the outer peripheral end of the clutch drum 95 at intervals in the front-rear direction.

The clutch hub 96 is integrally formed with the primary input gear 92. The clutch hub 96 has a cylindrical shape extending rearward from the primary input gear 92, and faces the outer peripheral end of the clutch drum 95 at intervals from the inside in the radial direction of rotation. A plurality of clutch discs 102 are held in the clutch hub 96 at intervals in the front-rear direction. The clutch plate 101 and the clutch disc 102 are arranged so as to be 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-rear direction. The clutch piston 97 extends from the first primary shaft 81 outward in the axial direction of the first primary shaft 81, and the outer peripheral end portion is bent forward and extends. The tip of the outer peripheral end of the clutch piston 97 comes into contact with the clutch plate 101. Further, the clutch piston 97 is in liquid-tight contact with the clutch drum 95, and a hydraulic chamber 103 for supplying the oil pressure acting on the clutch piston 97 is formed between the clutch drum 95 and the clutch piston 97. ing.

The canceller 98 is provided between the clutch hub 96 and the clutch piston 97. The 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. As a result, the 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 in which they are separated from each other by the urging force of the return spring 105.

The clutch piston 97 moves to the clutch plate 101 side by the flood pressure supplied to the hydraulic chamber 103 and presses the clutch plate 101. By this pressing, the clutch plate 101 and the clutch disc 102 are in pressure contact with each other, and the forward clutch 94 is engaged. The engagement of the forward clutch 94 prohibits the rotation of the primary input gear 92 with respect to the first primary shaft 81, and when the primary input gear 92 rotates, the first primary shaft 81 rotates integrally with the primary input gear 92. When the oil pressure is released from the engaged state of the forward clutch 94, the clutch piston 97 is separated from the clutch plate 101 by 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 the clutch disc 102 and the clutch plate 101 is released, and the forward clutch 94 is released. The release of the forward clutch 94 allows the rotation of the primary input gear 92 with respect to the first primary shaft 81, 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 on the front side of the second secondary shaft 112. The secondary pulley 64 is supported by the second secondary shaft 112. A circular connecting 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 the outer peripheral surface of the second secondary shaft 112 is spline-fitted with the inner peripheral surface of the connection recess 113 in the connection recess 113. .. The first secondary shaft 111 is the same component as the first primary shaft 81, as is understood in comparison with the first primary shaft 81. By sharing the first primary shaft 81 and the first secondary shaft 111, the number of types of parts constituting the transmission unit 1 (CVT4) can be reduced, and the manufacturing cost of the transmission unit 1 can be reduced. The front end of the first secondary shaft 111 is rotatably supported by the first case 11 via a bearing 114. The front end of the second secondary shaft 112 is rotatably supported by the second case 12 via a bearing 115. The 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 on the second secondary shaft 112 on the rear side of the bearing 114 so as to be relatively rotatable via the needle bearing 122.

A reverse clutch 123 is provided that allows / prohibits rotation of the secondary input gear 121 with respect to the first secondary shaft 111 by utilizing the space between the secondary input gear 121 and the pump case 47 of the oil pump 46. A part of the reverse clutch 123 overlaps with the oil pump 46 in the rotational radial direction (overlaps 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 inner peripheral end of the clutch drum 124 is fixed to the first secondary shaft 111, extends from the first secondary shaft 111 in the shaft radial direction, and the outer peripheral end portion bends and extends toward the secondary input gear 121, that is, the front side. A plurality of clutch plates 131 are held side by side at the outer peripheral end of the clutch drum 124 at intervals in the front-rear direction.

The clutch hub 125 is integrally formed with the 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 at a distance from the inside in the radial direction of rotation. A plurality of clutch discs 132 are held in the clutch hub 125 at intervals in the front-rear direction. The clutch plate 131 and the clutch disc 132 are arranged so as to be arranged alternately in the central axis direction. The number of each of the clutch plates 131 and the clutch disc 132 is larger than the number of each of the clutch plates 101 and the clutch disc 102 of the 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-rear direction. The clutch piston 126 extends from the first secondary shaft 111 outward in the axial direction of the first secondary shaft 111, and the outer peripheral end portion thereof bends forward and extends. The tip of the outer peripheral end of the clutch piston 126 comes into contact with the clutch plate 131. Further, the clutch piston 126 is in liquid-tight contact with the clutch drum 124, and a hydraulic chamber 133 to which the oil pressure acting on the clutch piston 126 is supplied is formed between the clutch drum 124 and the clutch piston 126. ing.

The canceller 127 is provided between the clutch hub 125 and the clutch piston 126. The 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, the 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 in which they are separated from each other by the urging force of the return spring 135.

The clutch piston 126 moves to the clutch plate 131 side by the flood pressure supplied to the hydraulic chamber 133 and presses the clutch plate 131. By this pressing, the clutch plate 131 and the clutch disc 132 are in pressure contact with each other, and the reverse clutch 123 is engaged. The engagement of the reverse clutch 123 prohibits the rotation of the secondary input gear 121 with respect to the first secondary shaft 111, and when the secondary input gear 121 rotates, the first secondary shaft 111 rotates integrally with the secondary input gear 121. When the oil pressure is released from the engaged state of the reverse clutch 123, the clutch piston 126 is separated from the clutch plate 131 by 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 the clutch disc 132 and the clutch plate 131 is released, and the reverse clutch 123 is released. By releasing the reverse clutch 123, the 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. The 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. The front end of the reverse idler shaft 141 is rotatably supported by the first case 11 via a bearing 144. The rear end of the reverse idler shaft 141 is rotatably supported by the second case 12 via a bearing 145. Further, as shown in FIG. 3, the position of the reverse idler shaft 141 in the vertical direction is accommodated between the uppermost position and the lowermost position of the turbine runner 24 of the torque converter 3, and the reverse idler shaft 141 is located in the front-rear direction with the turbine runner 24. Facing.

The first reverse gear 142 is integrally formed 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 arranged 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 so as to have a common axis extending in the vertical direction along the front-rear direction of the vehicle in the front-rear direction at intervals in the front-rear direction.

The front end of the output shaft 44 is rotatably supported by the adapter 86 via a needle bearing 146. The adapter 86 substantially entirely overlaps the secondary movable sheave 76 and the piston 77 of the secondary pulley 64 in the front-rear direction (overlapping when viewed from the rotational radial direction of the secondary pulley 64). As a result, the output shaft 44 is brought close to the secondary movable sheave 76 to the utmost limit, and is arranged so as to overlap the piston 77 in the front-rear direction. As a result, the front-rear length of the transmission unit 1 (CVT4) is shortened. Further, the output shaft 44 is rotatably supported by the third case 13 via the bearing 147 in which the inner ring of the bearing 147 is externally fitted in a portion spaced rearward from the support portion by the needle bearing 146. Has been done.

An output shaft gear 148 is integrally formed on the output shaft 44 between the support portion by the needle bearing 146 and the support portion by the bearing 147. Correspondingly, the secondary output gear 149 is supported on the secondary shaft 62 (second secondary shaft 112) adjacent to the rear side of the piston 77 of the secondary pulley 64 by spline fitting so as not to rotate relative to each other. .. The output shaft gear 148 and the secondary output gear 149 are meshed with each other, and the output shaft gear 148 has a larger gear diameter than the secondary output gear 149. The output shaft gear 148 overlaps the piston 77 of the secondary pulley 64 in the vertical direction (overlaps when viewed in the front-rear direction).

<Oil supply structure>
FIG. 4 is a diagram showing the configuration inside the second case 12, and is a view of the configuration inside the second case 12 as viewed from the rear side. FIG. 5 is a view of the portion of the transmission unit 1 including the second case 12 as viewed from below.

A valve body 151 is provided on the bottom of the second case 12. Specifically, at the bottom of the second case 12, the valve body 151 is arranged below the secondary pulley 64. The valve body 151 is formed with a hydraulic circuit including various valves for controlling the supply of oil to each part of the transmission unit 1. As shown in FIG. 3, the oil pan 152 is fixed to the second case 12 from the lower side with a plurality of bolts.

Further, a strainer 171 is provided on the bottom of the second case 12, as shown in FIGS. 4 and 5. Specifically, at the bottom of the second case 12, the strainer 171 is located below the primary pulley 63 and at the right rear corner of the second case 12.

Oil is stored in the oil pan 152, and the strainer 171 is immersed in the oil. By the rotation of the pump gear 49 of the oil pump 46, the oil stored in the oil pan 152 is sucked up by the strainer 171 and supplied from the strainer 171 to the valve body 151. Then, oil is supplied from the valve body 151 as hydraulic oil or lubricating oil to each part that requires oil supply.

The hydraulic oil is supplied to the hydraulic chamber 103 of the forward clutch 94 through an oil passage 153 extending upward from the valve body 151 along the axial direction of the primary shaft 61 at a position overlapping the oil pump 46 in the front-rear direction. In the forward clutch 94, the clutch drum 95 is arranged on the oil pump 46 side with respect to the clutch hub 96, and the hydraulic chamber 103 is closer to the oil pump 46 as compared with the configuration in which the configuration of the forward clutch 94 is reversed back and forth. .. Therefore, in the configuration of the forward clutch 94, the distance from the oil passage 153 to the hydraulic chamber 103 can be shortened, and the oil passage length from the oil pump 46 to the hydraulic chamber 103 can be shortened as compared with the configuration in which the configuration is reversed. It is possible to improve the responsiveness by shortening the oil passage length.

Hydraulic oil is supplied to the hydraulic chamber 133 of the reverse clutch 123 through an oil passage 154 extending upward from the valve body 151 along the axial direction of the primary shaft 61 at a position overlapping the oil pump 46 in the front-rear direction. In the reverse clutch 123, the clutch drum 124 is arranged on the oil pump 46 side with respect to the clutch hub 125, and the hydraulic chamber 133 is closer to the oil pump 46 than the configuration in which the reverse clutch 123 is reversed back and forth. .. Therefore, in the configuration of the reverse clutch 123, the distance from the oil passage 154 to the hydraulic chamber 133 can be shortened, and the oil passage length from the oil pump 46 to the hydraulic chamber 133 can be shortened as compared with the configuration in which the configuration is reversed. It is possible to improve the responsiveness by shortening the oil passage length.

Further, as shown in FIG. 3, a partition wall 155 is integrally formed in the second case 12. The partition wall 155 extends along the outer periphery of the primary pulley 63 to a position facing the left end of the primary pulley 63 in the vertical direction beyond the position facing the lower end of the primary pulley 63 in the vertical direction toward the secondary pulley 64 side. .. The partition wall 155 can isolate the primary pulley 63 from the oil stored in the oil pan 152, and can prevent the lower portion of the primary pulley 63 from being immersed in the oil.

When the vehicle moves forward, the primary pulley 63 rotates clockwise when viewed from the rear side, so even if oil accumulates on the partition wall 155, the accumulated oil is scraped out to the open end side of the partition wall 155 by the primary pulley 63. .. As a result, it is possible to prevent the lower portion of the primary pulley 63 from being immersed in the oil, reduce the mechanical loss caused by the oil acting as a resistance to the rotation of the primary pulley 63, and improve the fuel efficiency of the vehicle.

As shown in FIG. 1, a primary shaft core oil passage 161 is formed in the second primary shaft 82 of the primary shaft 61. The primary shaft core oil passage 161 is open at the rear end face of the second primary shaft 82. Further, on the second primary shaft 82, open oil passages 162 and 163 are formed at intervals in the axial direction. Each end of the open oil passages 162 and 163 is connected to the primary axial core oil passage 161, and the open oil passages 162 and 163 communicate with the primary axial core oil passage 161. The other end of the open oil passage 162 is open on the outer peripheral surface of the second primary shaft 82. The primary movable sheave 72 is formed with a substantially cylindrical outer fitting portion 164 that is outerly fitted to the second primary shaft 82, and the outer fitting portion 164 is formed through a communication oil passage 165. .. Depending on the position of the primary movable sheave 72, only the open oil passage 162 communicates with the hydraulic chamber 74 of the primary pulley 63, and only the open oil passage 163 communicates with the hydraulic chamber 74 via the communication oil passage 165, or the open oil. Both roads 162 and 163 communicate with the hydraulic chamber 74.

Oil is supplied to the primary axial oil passage 161 from the valve body 151. The oil supplied to the primary axial core oil passage 161 passes through at least one of the open oil passages 162 and 163 and the communication oil passage 165 in this order and flows into the hydraulic chamber 74, and the oil in the hydraulic chamber 74 communicates. It passes through at least one of the oil passage 165 and the open oil passages 162 and 163 in this order and flows out to the primary axial core oil passage 161.

A secondary shaft core oil passage 166 is formed in the second secondary shaft 112 of the secondary shaft 62. The secondary shaft core oil passage 166 is open at the rear end face of the second secondary shaft 112. An open oil passage 167 is formed in the second secondary shaft 112. One end of the open oil passage 167 is connected to the secondary axle core oil passage 166, and the open oil passage 167 communicates with the secondary axle core oil passage 166. The other end of the open oil passage 167 is open on the outer peripheral surface of the second secondary shaft 112. The secondary movable sheave 76 is formed with a substantially cylindrical outer fitting portion 168 that is outerly fitted to the second secondary shaft 112, and the outer fitting portion 168 is formed through a communication oil passage 169. .. Regardless of the position of the secondary movable sheave 76, the open oil passage 167 communicates with the hydraulic chamber 78 of the secondary pulley 64 via the communication oil passage 169.

Oil is supplied from the valve body 151 to the secondary shaft oil passage 166. The oil supplied to the secondary axial core oil passage 166 passes through the open oil passage 167 and the communication oil passage 169 in this order and flows into the hydraulic chamber 78, and the oil in the hydraulic chamber 78 is opened in the communication oil passage 169 and the communication oil passage 169. It passes through the oil passage 167 in this order and flows out to the secondary axial core oil passage 166.

<Strainer>
FIG. 6 is a view of the strainer 171 as viewed from the front side.

The strainer 171 integrally includes a main body portion 172 and a pipe portion 173 extending from the main body portion 172.

The main body 172 is arranged side by side with the valve body 151 as shown in FIG. The main body 172 has a filtration chamber 175 in which the filter medium 174 is housed, a discharge port 176 for discharging oil toward the valve body 151, and a flow path 177 connected to the upper portion of the filtration chamber 175 and the discharge port 176. And are formed. The flow path 177 extends downward from the portion connected to the upper part of the filtration chamber 175, bends and extends toward the discharge port 176, bends upward at a position facing the discharge port 176 from the lower side, and bends upward at the position facing the discharge port 176. Extends to. The discharge port 176 is connected to an oil suction path 178 that sucks the oil discharged from the discharge port 176 into the oil pump 46. The oil suction path 178 is formed in the second case 12.

As shown in FIG. 5, the pipe portion 173 extends from the lower portion of the filtration chamber 175 of the main body portion 172 to the front side, and extends while curving the lower side of the valve body 151 to the left side, and the tip portion thereof is the second case. It is located in the central part of 12. The tube portion 173 is formed in a hollow tubular shape, and the inside thereof communicates with the filtration chamber 175. Further, as shown in FIGS. 5 and 6, a suction port 179 for sucking the oil stored in the oil pan 152 into the pipe portion 173 is formed on the lower surface of the tip portion of the pipe portion 173.

When the oil pump 46 is driven, the suction force of the oil pump 46 sucks the oil stored in the oil pan 152 from the suction port 179 into the pipe portion 173. The oil sucked into the pipe portion 173 flows through the pipe portion 173 toward the main body portion 172, flows into the lower part of the filtration chamber 175 of the main body portion 172, and passes through the filter material 174 toward the upper part of the filtration chamber 175. To do. When the oil passes through the filter medium 174, the foreign matter contained in the oil is captured by the filter medium 174, and the foreign matter is removed from the oil. The oil that has reached the upper part of the filtration chamber 175 flows out to the flow path 177 and flows through the flow path 177 toward the discharge port 176. Then, the oil is discharged from the discharge port 176, flows through the oil suction path 178, and is sucked into the oil pump 46.

A discharge port 181 is formed in the main body 172 at the uppermost position on the upper surface of the filtration chamber 175. The discharge port 181 is connected to one end of the discharge path 182 formed in the second case 12. The other end of the discharge path 182 is connected to the oil suction path 178. The inner cross-sectional area of the discharge path 182 is smaller than the inner cross-sectional area of the oil suction path 178. As a result, when the oil pump 46 is driven, oil is secondarily discharged from the filtration chamber 175 to the discharge path 182 via the discharge port 181.

<Power transmission path>
FIG. 7 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, the forward clutch 94 is engaged and the reverse clutch 123 is released. The 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 primary shaft 61 via the primary input gear 92 by the engagement of the 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 secondary input gear 121 becomes the secondary shaft 62 due to the release of the reverse clutch 123. It slips with respect to (first secondary shaft 111), and power is not transmitted to the secondary shaft 62.

The power transmitted to the primary shaft 61 is changed at a belt gear ratio corresponding to the pulley ratio of the primary pulley 63 and the secondary pulley 64, and is transmitted to the secondary shaft 62. Then, 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 the propeller shaft (not shown), and is output from the propeller shaft. 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 the primary input gear 92 is larger than the gear diameter of the input shaft gear 91, the power of the input shaft 41 is decelerated by the input shaft gear 91 and the primary input gear 92 and transmitted to the 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 decelerated by the secondary output gear 149 and the output shaft gear 148 and transmitted to the output shaft 44. .. Therefore, when the vehicle is moving forward, the input shaft gear 91 and the primary input gear 92 form a primary reduction gear mechanism 201 that reduces the power in the power transmission path from the input shaft 41 to the output shaft 44, and the output shaft gear 148 and the output shaft gear 148 The secondary output gear 149 further constitutes a secondary reduction gear mechanism 202 that further reduces the power.

For example, a configuration in which the secondary shaft 62 is directly connected to the output shaft 44 and the secondary reduction gear mechanism 202 is omitted can be considered. In this configuration, in order to obtain the reduction ratio by the primary reduction gear mechanism 201 and the secondary reduction gear mechanism 202, the reduction ratio of the primary reduction gear mechanism 201 must be increased, and the gear diameter of the primary input gear 92 must be increased. There is a need to. Increasing the gear diameter of the primary input gear 92 increases the size of the CVT 4. Therefore, in the configuration including the secondary reduction gear mechanism 202 in addition to the primary reduction gear mechanism 201, the size of the CVT 4 can be reduced as compared with the configuration in which the secondary reduction gear mechanism 202 is omitted.

Further, by providing the primary reduction gear mechanism 201 and the secondary reduction gear mechanism 202, when the engine specifications are changed, the primary reduction gear mechanism 201 can be provided without changing the secondary reduction gear mechanism 202. By changing the design of at least one of the input shaft gear 91 and the primary input gear 92, the CVT 4 can be made to correspond to the changed specifications of the engine.

When the vehicle is moving backward, the forward clutch 94 is released and the reverse clutch 123 is engaged. The 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 the engagement of the reverse clutch 123. .. At this time, the secondary shaft 62 rotates in the direction opposite to that when the vehicle is moving 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 primary input gear 92 becomes the primary shaft 61 due to the release of the forward clutch 94. It slips with respect to (first primary shaft 81), and power is not 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, output from the output shaft 44 to the propeller shaft, and from the propeller shaft to the rear differential gear and the drive shaft. It is transmitted to the left and right rear wheels via.

Since 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 decelerated 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 decelerated by the secondary output gear 149 and the output shaft gear 148 and transmitted to the output shaft 44. .. Therefore, when the vehicle is moving backward, the input shaft gear 91, the reverse transmission mechanism 43, and the secondary input gear 121 form a primary reduction gear mechanism 203 that reduces the power in the power transmission path from the input shaft 41 to the output shaft 44. The output shaft gear 148 and the secondary output gear 149 form a secondary reduction gear mechanism 202 that further reduces the power.

<Effect>
As described above, the strainer 171 has a main body portion 172 in which the filter material 174 is housed, and a pipe portion 173 in which the suction port 179 is formed. Since the filter material 174 is not housed in the pipe portion 173, the pipe portion 173 can be formed thinner than the main body portion 172. Therefore, the main body 172 is arranged side by side with the valve body 151, and the pipe portion 173 extends from the main body 172 to extend below the valve body 151, so that the entire strainer is arranged below the valve body 151. Compared with the configuration, the size of the transmission unit 1 (CVT4) can be reduced in the vertical direction. Moreover, since the suction port 179 is formed at a position facing the central portion of the oil pan 152, the suction port 179 collects in the oil pan 152 regardless of the behavior of the oil due to turning, starting, and stopping of the vehicle on which the transmission unit 1 is mounted. The oil can be satisfactorily sucked into the strainer 171 (inside the pipe portion 173) from the suction port 179.

Further, in the CVT 4, the primary shaft 61 and the secondary shaft 62 are separately arranged on the left and right sides with respect to the input shaft 41. The primary shaft 61 and the secondary shaft 62 are offset to one side and the other side in the vertical direction with respect to the input shaft 41, respectively. Specifically, in the CVT 4, the primary shaft 61 is arranged at a position lower than the input shaft 41, and the secondary shaft 62 is arranged at a position above the input shaft 41. As a result, the distance between the primary shaft 61 and the secondary shaft 62 in the vertical direction can be shortened. As a result, the size of the transmission unit 1 in the vertical direction can be further reduced.

A valve body 151 having a relatively large vertical size is arranged below the secondary pulley 64 (secondary shaft 62) located at a relatively high position, and the primary pulley located at a relatively low position. Below the 63 (primary shaft 61), a strainer 171 having a relatively small size in the vertical direction is arranged. With this layout, the size of the transmission unit 1 in the vertical direction can be further reduced.

As a result, even in a vehicle such as a commercial vehicle having a low floor, it is possible to mount the speed change unit 1 on the vehicle while ensuring the minimum ground clearance of the vehicle.

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

For example, in the above-described embodiment, 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, but depending on the size (output) of the engine combined with the CVT 4, the first reverse gear 142 1 The gear diameter of the reverse gear 142 may be smaller than the gear diameter of the input shaft gear 91.

Further, although the CVT4 for vertical installation is taken up as an example of the transmission, the present invention can also be applied to a transmission which is horizontally installed so that the input shaft extends in the left-right direction of the vehicle.

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. Further, the speed change mechanism provided in the speed change unit 1 is not limited to the stepless speed change mechanism 42, and may be a stepped speed change mechanism.

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

1: Transmission unit (transmission)
4: CVT (transmission)
41: Input shaft 42: Continuously variable transmission mechanism (transmission mechanism)
61: Primary shaft 62: Secondary shaft 151: Valve body 171: Strainer

Claims (1)

The case that makes up the outer shell and
The input shaft to which the power of the drive source is input and
A continuously variable transmission mechanism having a primary shaft and a secondary shaft extending in parallel with the input shaft, respectively, and shifting and transmitting power from the primary shaft to the secondary shaft.
A valve body that supplies oil to the continuously variable transmission mechanism
Including a strainer that sucks up the oil accumulated in the bottom of the case and supplies it to the valve body.
The primary axis and the secondary axis are divided into left and right with respect to the input axis when viewed from the axial direction of the input axis, and one is arranged so as to be located at a higher position than the other.
The valve body is located below the primary shaft and one of the secondary shafts.
The strainer is a transmission located below the primary shaft and the other of the secondary shafts.