JP7433701B2 - oil supply structure - Google Patents

Description

The present invention relates to a structure for supplying oil to a clutch or the like.

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.

As a transmission for a vehicle in which an engine is mounted vertically, a vertically mounted CVT (Continuously Variable Transmission) has already been provided. A CVT for vertical installation is arranged so that the input shaft is oriented vertically with respect to the longitudinal direction of the vehicle body. The output shaft that outputs power to the propeller shaft is spaced rearward from the input shaft, and an endless belt is wound around the primary and secondary pulleys between the input shaft and the output shaft. A continuously variable transmission mechanism is provided. Engine power is input to the input shaft via a torque converter. The power input to the input shaft is changed in speed by the continuously variable transmission mechanism and transmitted to the output shaft. The power output from the output shaft to the propeller shaft is distributed to the left and right drive shafts by a differential gear, and then transmitted to the left and right rear wheels.

Japanese Patent Application Publication No. 2012-192855

A CVT with such a configuration can be made into a 4WD (four-wheel drive) specification by connecting a transfer to the output shaft so that the power of the output shaft is transmitted to the left and right front wheels by the transfer. can. In addition, if a hydraulic clutch (wet clutch) is installed to switch the transmission/cutoff of power from the output shaft, it can be switched between two-wheel drive mode using the left and right rear wheels and a four-wheel drive mode using the left and right front wheels and rear wheels. becomes possible.

However, unless some ingenuity is put into the configuration of the oil passages for supplying oil (hydraulic pressure) to clutches, etc., it becomes difficult to form the oil passages, which reduces the productivity of power transmission devices including CVTs, transfers, and clutches. Deteriorate.

An object of the present invention is to provide an oil supply structure that is easy to process to form an oil passage for supplying oil to a clutch or the like.

In order to achieve the above object, an oil supply structure according to the present invention is an oil supply structure applied to a vehicle having left and right main drive wheels and left and right auxiliary drive wheels, and which transmits power to the main drive wheels. a first transmission shaft, a second transmission shaft that transmits power to the auxiliary drive wheels, a transmission mechanism that transmits power between the first transmission shaft and the second transmission shaft, and a transmission mechanism that transmits the power of the first transmission shaft. a clutch that is engaged/released for transmitting/disconnecting the transmission, and a cylindrical member externally fitted and fixed to the first transmission shaft; An axial oil passage through which oil flows for lubrication of the surroundings is formed, and a circumferential oil passage through which oil flows for engagement of the clutch is formed between the first transmission shaft and the cylindrical member. There is.

According to this configuration, when the clutch is released, power is transmitted from the first transmission shaft to the main drive wheels, but since power is not transmitted from the first transmission shaft to the transmission mechanism, power is not transmitted to the second transmission shaft. First, no power is transmitted to the auxiliary drive wheels. At this time, the vehicle is in a two-wheel drive state using the left and right main drive wheels. On the other hand, when the clutch is engaged, power is transmitted from the first transmission shaft to the main drive wheels, and power is also transmitted from the first transmission shaft to the transmission mechanism, so that power is transmitted to the second transmission shaft, Power is transmitted from the second transmission shaft to the sub-drive wheels. At this time, the vehicle is in a four-wheel drive state using the left and right main drive wheels and the auxiliary drive wheels.

An axial oil passage is formed along the axial center of the first transmission shaft. The shaft center oil passage is used as an oil passage through which oil for lubrication around the first transmission shaft flows. Further, a cylindrical member is externally fitted and fixed to the first transmission shaft, and a circumferential oil passage is formed between the cylindrical member and the first transmission shaft. The circumferential oil passage is used as an oil passage through which oil for engaging the clutch flows. Therefore, it is not necessary to form an oil passage in the first transmission shaft through which oil for engaging the clutch flows.

For example, two oil passages extending in the axial direction are formed within the first transmission shaft, one oil passage is used as an oil passage through which oil for lubrication around the first transmission shaft flows, and the other oil passage is used as an oil passage through which oil flows for lubrication around the first transmission shaft. A structure is conceivable in which the oil passage is used as an oil passage through which oil for engaging the clutch flows. However, in this structure, the diameter (hole diameter) of each oil passage becomes small, making processing for forming the oil passage difficult. Moreover, oil passages for guiding oil from each oil passage to the outer circumferential surface of the first transmission shaft are also required, and the number of processes required to form these oil passages increases. Therefore, productivity is poor.

On the other hand, in a structure in which an axial oil passage and a circumferential oil passage are formed, the oil passage that extends in the axial direction within the first transmission shaft is one of the axial oil passages, and two oil passages are formed. Therefore, the diameter of the axial oil passage is not limited to a small diameter. Therefore, processing for forming the axial oil passage within the first transmission shaft is easy. Further, since the number of oil passages for guiding oil from the inside of the first transmission shaft to the outer circumferential surface is small, the number of processes required to form the oil passages is small. Furthermore, the formation of the circumferential oil passage does not require drilling of the first transmission shaft.

Therefore, it is easy to form the axial oil passage and the circumferential axial oil passage. Therefore, productivity of the power transmission device that transmits power to the main drive wheels and the auxiliary drive wheels can be improved.

The oil supply structure includes a main valve body that regulates and outputs hydraulic pressure, an adapter case that is connected to the cylindrical member, and an adapter case that is supported by the adapter case and that regulates and outputs the hydraulic pressure output from the main valve body as necessary. The adapter case may further include a sub-valve body for output, and the adapter case may be formed with an adapter case oil passage that communicates with the circumferential oil passage and is supplied with oil output from the sub-valve body.

With this structure, it is possible to shorten the path from when the pressure of oil for engaging the clutch is regulated until it is supplied to the clutch. Therefore, loss of oil pressure (clutch pressure) on the supply path can be suppressed, and responsiveness of changes in the engagement state of the clutch to changes in clutch pressure can be improved.

According to the present invention, it is easy to form an oil passage for supplying oil to a clutch, etc., and productivity of a power transmission device including a first transmission shaft, a second transmission shaft, a transmission mechanism, and a clutch is improved. can be achieved.

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 rear end portion (a portion including a transfer) of the transmission unit on a larger scale than in FIG. 1; FIG. 2 is a skeleton diagram schematically showing the configuration of a CVT and a transfer.

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

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

The transmission unit 1 is a unit that is mounted on a vehicle and changes the speed of power generated by an engine 2 (E/G) 2 as a drive source for driving. The vehicle is a part-time 4WD (four-wheel-drive) vehicle based on FR (front engine, rear drive).

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

The transmission unit 1 includes a torque converter 4, a CVT (Continuously Variable Transmission) 5, and a transfer 6 within a unit case 3 forming an outer shell.

<Unit case>
Unit case 3 includes a transmission case that accommodates torque converter 4 and CVT 5, and a transfer case that accommodates transfer 6. The transmission case is composed of three parts: a first transmission case 11, a second transmission case 12, and a third transmission case 13. The transfer case is composed of two parts: a first transfer case 14 and a second transfer case 15. The first transmission case 11, the second transmission case 12, the third transmission case 13, the first transfer case 14, and the second transfer case 15 are made of, for example, an aluminum alloy and are cast by die-casting.

The first transmission case 11, the second transmission case 12, and the third transmission case 13 are arranged in this order from the front side (engine 2 side). The first transmission case 11 and the second transmission case 12 are fastened with the bolts 16, and the second transmission case 12 and the third transmission case 13 are fastened with the bolts 17, so that the first transmission case 11 and the second transmission Case 12 and third transmission case 13 are integrated.

The first transfer case 14 and the second transfer case 15 are arranged in this order from the front side. The first transfer case 14 and the second transfer case 15 are integrated by being fastened with bolts 18. The first transfer case 14 is fastened to the third transmission case 13 with bolts 19, so that the transmission case and the transfer case are integrated.

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

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

The pump impeller 22 is arranged on the rear side of the front cover 21. 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 2 when the pump impeller 22 and the turbine runner 24 are directly connected.

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

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

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

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

In the following description, the direction in which the axis of the input shaft 41 extends will be referred to as the "axial direction." Further, a direction perpendicular to the axial direction, that is, a radial direction of the input shaft 41 is referred to as a "shaft radial direction."

A rear end portion of the input shaft 41 is rotatably supported by a mechanical oil pump 45 disposed within the second transmission case 12. Specifically, the oil pump 45 includes a pump case 46, a pump cover 47 joined to the pump case 46 from the rear side, a pump gear 48 disposed in a space inside the pump case 46, and a pump gear 48 that cannot rotate relative to the pump gear 48. A pump shaft 49 coupled to the pump shaft 49 is provided. The pump cover 47 is fixed to the second transmission case 12 and closes off the space inside the pump case 46 from the rear side. A substantially cylindrical recess 51 is formed at the front end of the pump case 46 on the rear side. The rear end of the input shaft 41 is inserted into the recess 51 and is rotatable to the pump case 46 via a radial bearing 52 interposed between the peripheral surface of the input shaft 41 and the inner peripheral surface of the recess 51. Supported.

Further, a thrust bearing 53 is interposed between the rear end surface of the input shaft 41 and the bottom surface of the recess 51. This reduces mechanical loss when the input shaft 41 rotates.

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

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

The primary shaft 54 extends parallel to the input shaft 41 between the first transmission case 11 and the second transmission case 12 at a position spaced apart to the lower right from the input shaft 41 when viewed from the rear side of the vehicle. It is rotatably provided around its axis.

The secondary shaft 55 is located between the first transmission case 11 and the second transmission case 12 and is parallel to the input shaft 41 at a position spaced apart to the upper left when viewed from the rear side of the vehicle with respect to the axis of the input shaft 41. It extends and is rotatably provided around its axis.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

<Transfer>
FIG. 2 is a cross-sectional view showing a rear end portion of the transmission unit 1, that is, a portion including the transfer 6, on a larger scale than in FIG. Hereinafter, the configuration of the transfer 6 will be described with appropriate reference to FIG. 2 in addition to FIG. 1.

The transfer 6 is a mechanism that transmits the power (rotation) of the output shaft 43 to the front wheels of the vehicle. The transfer 6 includes a transmission shaft 111, a first sprocket 112, a second sprocket 113, a chain 114, and a 4WD clutch 115.

The transmission shaft 111 extends parallel to the output shaft 43 and straddles the first transfer case 14 and the second transfer case 15 at a position spaced apart from the output shaft 43 in the shaft radial direction. There is. An inner ring of a ball bearing 116 is fixed to the rear end of the transmission shaft 111 by press fitting. Further, an inner ring of a ball bearing 117 is fixed to the transmission shaft 111 by press fitting at a position spaced from the ball bearing 116 on the front side. The outer ring of the ball bearing 116 is fixedly held in the second transfer case 15, and the outer ring of the ball bearing 117 is fixedly held in the first transfer case 14, so that the transmission shaft 111 is connected to the first transfer case 15. 14 and a second transfer case 15 in a rotatable manner.

The first sprocket 112 is rotatably supported by the first transfer case 14 and the second transfer case 15, and is fitted onto the output shaft 43 so as to be relatively rotatable. Specifically, the first sprocket 112 includes a substantially annular plate-shaped sprocket portion 121 that surrounds the output shaft 43, a front side extension portion 122 that extends forward from the inner peripheral portion of the sprocket portion 121, and a sprocket portion 121 that has a substantially annular plate shape that surrounds the output shaft 43. It integrally has a rear side extension part 123 extending rearward from the inner peripheral part of the part 121. A plurality of teeth are formed on the outer periphery of the sprocket portion 121 at equal intervals in the circumferential direction. An inner ring of a ball bearing 124 is press-fitted into the front extending portion 122 . Further, an inner ring of a ball bearing 125 is fitted onto the rear side extension portion 123 by press fitting. The outer ring of the ball bearing 124 is fixedly held by the first transfer case 14, and the outer ring of the ball bearing 125 is fixedly held by the second transfer case 15. As a result, the first sprocket 112 is rotatably supported by the first transfer case 14 and the second transfer case 15 via the ball bearings 124 and 125 while being fitted onto the output shaft 43 so as to be relatively rotatable. ing.

The second sprocket 113 is formed integrally with the transmission shaft 111 between the ball bearings 116 and 117, and has a substantially annular plate shape extending from the transmission shaft 111 in the shaft radial direction. A plurality of teeth are formed on the outer periphery of the second sprocket 113 at equal intervals in the circumferential direction.

The chain 114 is formed in an endless shape and is wound around the sprocket portion 121 of the first sprocket 112 and the second sprocket 113.

The 4WD clutch 115 is provided in front of the first sprocket 112. The 4WD clutch 115 includes a clutch drum 131, a clutch hub 132, a clutch piston 133, and a canceller 134.

A substantially cylindrical cylindrical member 135 is externally fitted and fixed to the output shaft 43 between the output shaft gear 101 and the first sprocket 112 . A space is provided between the cylindrical member 135 and the first sprocket 112. At a central portion of the cylindrical member 135 in the axial direction and at a position facing the rear end portion of the secondary shaft 55 in the radial direction of the shaft, a flange-shaped connecting portion 136 that extends in the radial direction of the shaft is connected to the cylindrical member 135. It is formed in one piece.

The clutch drum 131 is rotationally symmetrical about the axis of the output shaft 43, and has a substantially annular shape surrounding the entire circumference of the connecting portion 136 of the cylindrical member 135 when viewed in the axial direction. An inner peripheral end of the clutch drum 131 is fixed to a connecting portion 136. The clutch drum 131 extends from the inner peripheral end in a direction intersecting the axial direction, crosses the secondary shaft 55 to the rear side, and is bent rearward at a position facing the secondary shaft 55 from the rear side in the axial direction. It extends axially from that position. In other words, the clutch drum 131 includes an enlarged diameter portion 137 whose diameter increases rearward from the connection portion 136, and a substantially cylindrical cylinder that extends rearward in the axial direction from the rear end (outer peripheral end) of the enlarged diameter portion 137. The front end of the enlarged diameter part 137 faces the rear end of the secondary shaft 55 in the radial direction, and the cylindrical part 138 faces the rear end of the secondary shaft 55. They face each other from the rear in the axial direction. Further, a portion of the clutch drum 131 extending in the axial direction, that is, a cylindrical portion 138 faces the front extending portion 122 of the first sprocket 112 in the radial direction of the shaft. A plurality of clutch plates 139 are held on the inner circumferential surface of the cylindrical portion 138 so as to be spaced apart from each other in the axial direction.

A support member 141 is provided between the first sprocket 112 and the cylindrical member 135. The support member 141 includes a substantially cylindrical outer fitting portion 142 surrounding the output shaft 43 and a flange-shaped (annular plate-shaped) flange portion 143 extending in the shaft radial direction from the front end of the outer fitting portion 142. It has an integrated structure. The outer fitting part 142 enters between the front side extension part 122 of the first sprocket 112 and the output shaft 43, and the front side extension part 122 of the first sprocket 112 fits into the outer fitting part 142 and the cylindrical shape of the clutch drum 131. It faces the portion 138 in the axial radial direction. The outer circumferential surface of the outer fitting part 142 is coupled to the inner circumferential surface of the front side extension part 122 of the first sprocket 112 by spline fitting so that relative rotation is not possible. The inner circumferential surface of the outer fitting portion 142 is not in close contact with the circumferential surface of the output shaft 43, and a minute gap is created between the outer circumferential surface of the output shaft 43 and the inner circumferential surface of the outer fitting portion 142. There is. As a result, the support member 141 cannot rotate relative to the first sprocket 112, but can rotate relative to the output shaft 43. A thrust bearing 144 is interposed between the cylindrical member 135 and the support member 141 in order to reduce mechanical loss during their relative rotation.

The clutch hub 132 is rotationally symmetrical about the axis of the output shaft 43, and has a substantially annular shape that surrounds the entire circumference of the brim 143 of the support member 141 when viewed in the axial direction. An inner peripheral end of the clutch hub 132 is fixed to a flange-shaped portion 143. The clutch hub 132 extends outward in the radial direction of the shaft from the brim portion 143, and is bent rearward at a position spaced inward in the radial direction of the shaft relative to the cylindrical portion 138 of the clutch drum 131. It extends in the axial direction from. In other words, the clutch hub 132 includes a substantially annular plate-shaped portion 151 that extends from the flange portion 143 to the periphery, and a substantially circular plate-shaped portion 151 that extends rearward in the axial direction from the outer peripheral end of the circular plate portion 151. The cylindrical portion 152 is arranged inside the cylindrical portion 138 of the clutch drum 131 in the radial direction of the shaft, and the cylindrical portion 152 has a cylindrical portion 152. It has a heavy cylindrical shape. A plurality of clutch disks 153 are held on the outer peripheral surface of the cylindrical portion 152 in an axially spaced manner. Clutch plates 139 and clutch discs 153 are arranged alternately in the axial direction.

Clutch piston 133 is provided between clutch drum 131 and clutch hub 132 so as to be movable in the axial direction. The clutch piston 133 extends from the cylindrical member 135 toward the clutch plate 139 while repeatedly bending. A seal member 154 is provided in the middle of the clutch piston 133, and the seal member 154 contacts the clutch drum 131 in a liquid-tight manner regardless of the position of the clutch piston 133. As a result, a hydraulic chamber 155 is formed between the clutch drum 131 and the clutch piston 133 to which hydraulic pressure acting on the clutch piston 133 is supplied.

Canceller 134 is provided between clutch hub 132 and clutch piston 133. The canceller 134 is formed into a substantially annular plate shape. An inner peripheral end of the canceller 134 is fixed to a cylindrical member 135. A sealing member 156 is provided at the outer peripheral end of the canceller 134, and this sealing member 156 contacts the clutch piston 133 regardless of the position of the clutch piston 133. A return spring 157 is interposed between the clutch piston 133 and the canceller 134. Due to the biasing force (elastic force) of the return spring 157, the clutch piston 133 and the canceller 134 are elastically biased in a direction away from each other.

The clutch piston 133 moves toward the clutch plate 139 by the hydraulic pressure supplied to the hydraulic chamber 155 and presses the clutch plate 139. This pressing causes the clutch plate 139 and the clutch disc 153 to come into pressure contact, and the 4WD clutch 115 is engaged. By engaging the 4WD clutch 115, relative rotation between the clutch drum 131 and the clutch hub 132 is prevented, the support member 141 rotates together with the output shaft 43 and the cylindrical member 135, and the first Sprocket 112 rotates. The rotation (power) of the first sprocket 112 is transmitted to the second sprocket 113 via the chain 114, causing the second sprocket 113 to rotate in the same direction as the first sprocket 112. Then, the transmission shaft 111 rotates together with the second sprocket 113.

When the hydraulic pressure in the hydraulic chamber 155 is released from the engaged state of the 4WD clutch 115, the clutch piston 133 moves in a direction away from the canceller 134 due to the urging force of the return spring 157, and the clutch plate 139 is pressed by the clutch piston 133. is canceled. As a result, the pressure contact between clutch plate 139 and clutch disc 153 is released, and 4WD clutch 115 is released. By releasing the 4WD clutch 115, relative rotation between the clutch drum 131 and the clutch hub 132 is allowed. Therefore, even if the output shaft 43 and the cylindrical member 135 rotate, the rotation is not transmitted to the support member 141 and the first sprocket 112, and therefore, the rotation is not transmitted from the first sprocket 112 to the chain 114 and the second sprocket 113. and is not transmitted to the transmission shaft 111 either.

An adapter 161 and an adapter case 162 are provided between the primary shaft 54, the output shaft 43, and the 4WD clutch 115. The adapter 161 and the adapter case 162 are made of, for example, an aluminum alloy, and are cast by die casting. The adapter case 162 has a first oil passage forming part 163 and a second oil passage forming part 164.

The adapter 161 extends between the output shaft 43 and the primary shaft 54 in the shaft radial direction. The upper end of the adapter 161 protrudes rearward, and a substantially cylindrical recess 166 is formed in the protruding portion toward the front. The front end of the output shaft 43 is inserted into the recess 166. A radial bearing 167 is interposed between the circumferential surface of the output shaft 43 and the inner circumferential surface of the recess 166. A front end portion of the output shaft 43 is rotatably supported by the adapter 161 via a radial bearing 167. Furthermore, an annular stepped surface 168 along the shaft radial direction is formed on the output shaft 43 between a portion where the output shaft gear 101 is formed and a portion inserted into the recess 166. A thrust bearing 169 is interposed between the stepped surface 168 and the adapter 161.

The adapter 161 has a substantially cylindrical recess 171 formed on the rear side. The rear end of the primary shaft 54 is inserted into the recess 171. A ball bearing 172 is interposed between the circumferential surface of the primary shaft 54 and the inner circumferential surface of the recess 171. A rear end portion of the primary shaft 54 is rotatably supported by an adapter 161 via a ball bearing 172.

A bolt 173 is inserted into the lower end of the adapter 161 from the front side. The adapter 161 is attached to the third transmission case 13 by the bolt 173.

The first oil passage forming portion 163 of the adapter case 162 extends in the axial direction below the adapter 161, and its rear end portion extends in the radial direction of the shaft. A front surface 174 of the first oil passage forming portion 163 is in contact with a rear surface 175 of the second transmission case 12 . A first oil passage 176, a second oil passage 177, and a third oil passage 178 are formed in the first oil passage forming portion 163. The first oil passage 176 is an oil passage extending in the axial direction, and is open (opened) at the front surface 174. The second oil passage 177 extends in the axial radial direction at the rear end of the first oil passage forming portion 163. The second oil passage 177 is open at the lower surface of the first oil passage forming portion 163, but the opening is closed by screwing in the bolt 179. The rear end of the first oil passage 176 is connected to an intermediate portion of the second oil passage 177, and the first oil passage 176 and the second oil passage 177 are in communication with each other. The third oil passage 178 is an oil passage that extends in the axial direction at the upper end of the rear end portion of the first oil passage forming portion 163 . The front end of the third oil passage 178 is connected to the upper end of the second oil passage 177, and the second oil passage 177 and the third oil passage 178 are in communication with each other.

The second oil passage forming portion 164 of the adapter case 162 is provided above the first oil passage forming portion 163 with a space therebetween, and extends in the axial radial direction. A front end portion of the cylindrical member 135 is inserted through a substantially cylindrical connecting member 181 so as to be relatively rotatable. A fixing portion 182 extending in the radial direction of the shaft is formed in the connecting member 181, and the connecting member 181 is fixed to the third transmission case 13 by a bolt 183 inserted through the fixing portion 182. The upper surface 184 of the second oil passage forming part 164 is in contact with the peripheral surface of the connecting member 181. A fourth oil passage 185 and a fifth oil passage 186 are formed in the second oil passage forming portion 164 . The fourth oil passage 185 is an oil passage extending in the radial direction of the shaft, and is open (opened) at the upper surface 184 of the second oil passage forming portion 164 . The fifth oil passage 186 is an oil passage that extends in the axial direction at the lower end of the second oil passage forming portion 164 . The lower end of the fourth oil passage 185 is connected to the fifth oil passage 186, and the fourth oil passage 185 and the fifth oil passage 186 are in communication.

The first oil passage forming part 163 and the second oil passage forming part 164 are connected by a plate-shaped connecting part 187. A valve body mounting surface 188 is formed as a flat surface spanning the rear surfaces of the first oil passage forming part 163, the second oil passage forming part 164, and the connecting part 187. The third oil passage 178 and the fifth oil passage 186 are open (open) at the valve body mounting surface 188.

Note that the adapter case 162 is attached to the third transmission case 13 with bolts 189.

<Oil supply structure>
A valve body 191 is provided at the bottom of the second transmission case 12. A hydraulic circuit including various valves for controlling the supply of oil to each part of the transmission unit 1 is formed in the valve body 191 . Further, a strainer 192 is provided at the bottom of the second transmission case 12. The strainer 192 includes a main body part 193 arranged side by side with the valve body 191 and a pipe part 194 extending from the main part 193 and having a distal end disposed below the valve body 191. Further, an oil pan 195 is fixed to the second transmission case 12 from below with a plurality of bolts 196. The tip of the pipe portion 194 of the strainer 192 is located in the center of the oil pan 195, and the lower surface of the tip is opened as an oil suction port 197 for sucking oil stored in the oil pan 195. ing.

A suction force is generated by the rotation of the pump gear 48 of the oil pump 45, and the oil stored in the oil pan 195 is sucked into the pipe portion 194 from the oil suction port 197. The oil sucked into the pipe portion 194 flows within the pipe portion 194 toward the main body portion 193 and passes through a filtering material provided within the main body portion 193. As the oil passes through the filter medium, foreign substances contained in the oil are captured by the filter medium and removed from the oil. The oil that has passed through the filter medium is supplied to the valve body 191. Oil is then supplied as hydraulic oil or lubricating oil from the valve body 191 to various parts such as the continuously variable transmission mechanism 42 that require oil supply.

The hydraulic circuit formed in the valve body 191 includes a clutch modulator valve that regulates the oil pressure (line pressure) of the oil supplied to the valve body 191 by the action of the oil pump 45 to a clutch modulator pressure and outputs the clutch modulator pressure. A clutch modulator pressure oil passage 198 is formed in the second transmission case 12 through which clutch modulator pressure oil output from the clutch modulator valve flows.

A connection port 199 is formed in the second transmission case 12 on the mating surface of the adapter case 162 with the first oil passage forming portion 163, that is, on the rear surface 175 that the front surface 174 of the first oil passage forming portion 163 comes into contact with. Clutch modulator pressure oil passage 198 is connected to its connection port 199. Furthermore, an opening of a first oil passage 176 formed on the front surface 174 of the first oil passage forming portion 163 is connected to the connection port 199 . Thereby, the clutch modulator pressure oil passage 198 communicates with the first oil passage 176 via the connection port 199. Therefore, the clutch modulator pressure oil supplied from the valve body 191 to the clutch modulator pressure oil passage 198 is supplied from the clutch modulator pressure oil passage 198 to the first oil passage 176 via the connection port 199, and The oil flows from there to a second oil passage 177 and a third oil passage 178.

A small valve body 201 smaller than the valve body 191 is attached to the valve body attachment surface 188 of the adapter case 162 with a plurality of bolts 202. The small valve body 201 is provided as a dedicated valve body for controlling the 4WD clutch 115, and a hydraulic circuit for controlling the oil pressure supplied to the 4WD clutch 115 is formed in the small valve body 201. This hydraulic circuit includes, for example, a linear solenoid valve 203. The linear solenoid valve 203 is arranged across the inside and outside of the valve body 191. That is, the valve portion 204 of the linear solenoid valve 203 is located within the miniature valve body 201, and the solenoid portion 205, including the coil and plunger, is located outside the miniature valve body 201. By arranging the large solenoid portion 205 outside the small valve body 201, the small valve body 201 can be made smaller.

The small valve body 201 extends along the valve body mounting surface 188 of the adapter case 162, and its front surface, which is a surface facing the valve body mounting surface 188, is in contact with the valve body mounting surface 188. An inlet for introducing oil into the hydraulic circuit and an outlet for discharging oil from the hydraulic circuit are respectively formed as openings on the front surface. The inlet and outlet of the small valve body 201 are connected to the opening of the third oil passage 178 and the opening of the fifth oil passage 186 in the valve body mounting surface 188, respectively. Thereby, the oil at the clutch modulator pressure flowing through the third oil passage 178 is supplied from the inlet of the small valve body 201 to the hydraulic circuit inside the small valve body 201. By controlling the energization of the linear solenoid valve 203, the oil at the clutch modulator pressure supplied from the inlet of the small valve body 201 to the hydraulic circuit remains at the clutch modulator pressure or is reduced from the clutch modulator pressure. The oil is sent out from the outlet of the small valve body 201 to the fifth oil passage 186. The oil sent to the fifth oil passage 186 flows into the fourth oil passage 185 from the fifth oil passage 186 .

A clutch pressure supply oil passage 211 is formed between the output shaft 43 and the cylindrical member 135 by digging shallowly into the outer peripheral surface of the output shaft 43. The clutch pressure supply oil passage 211 extends in the axial direction, and is located at a position opposite to the upper surface 184 of the second oil passage forming portion 164 in the axial radial direction and to a position opposite to the hydraulic chamber 155 of the 4WD clutch 115 in the axial radial direction. It straddles the position. A communication groove 218 is formed in the cylindrical member 135 over the entire circumference at a position opposite in the axial radial direction to the opening of the fourth oil passage 185 formed on the upper surface 184 of the second oil passage forming part 164. At the same time, a first communication passage 212 is formed that communicates the communication groove 218 with the clutch pressure supply oil passage 211. Further, a second communication passage 213 is formed in the cylindrical member 135 to communicate the hydraulic chamber 155 of the 4WD clutch 115 and the clutch pressure supply oil passage 211. Furthermore, a connection hole 219 is formed in the connection member 181 to allow the fourth oil passage 185 and the communication groove 218 to communicate with each other. Therefore, oil flowing into the fourth oil path 185 from the fifth oil path 186 flows into the clutch pressure supply oil path 211 from the fourth oil path 185 via the connection hole 219, the communication groove 218, and the first communication path 212. It flows through the clutch pressure supply oil passage 211 toward the second communication passage 213 and flows into the hydraulic chamber 155 of the 4WD clutch 115 via the second communication passage 213. As a result, the hydraulic pressure (clutch pressure) obtained by regulating the clutch modulator pressure in the hydraulic circuit (linear solenoid valve 203) of the small valve body 201 is supplied to the hydraulic chamber 155 of the 4WD clutch 115.

Further, the output shaft 43 is formed with an axial oil passage 214 extending on the axial center thereof. Oil as lubricating oil is supplied from the valve body 191 to the axial oil passage 214 . The output shaft 43 is further formed with a plurality of distribution oil passages 215 and 216. One end of each of the distribution oil passages 215 and 216 is connected to the axial oil passage 214, and the distribution oil passages 215 and 216 communicate with the axial oil passage 214. The other ends of the distribution oil passages 215 and 216 are open at the outer peripheral surface of the output shaft 43. A lubricating oil passage 217 communicating with the distribution oil passage 215 is formed in the cylindrical member 135 . Thereby, the oil flowing through the shaft center oil passage 214 is supplied to the 4WD clutch 115 as lubricating oil via the distribution oil passage 215 and the lubricating oil passage 217. Further, the oil flowing through the shaft center oil passage 214 is supplied around the output shaft 43 as lubricating oil via the distribution oil passage 215.

The small valve body 201 is arranged in a space between the adapter case 162 and the 4WD clutch 115. A portion of the small valve body 201, particularly the portion where the linear solenoid valve 203 is arranged, overlaps the 4WD clutch 115 in the axial direction (overlaps when viewed in the axial radial direction). By overlapping a portion of the small valve body 201 with the 4WD clutch 115 in the axial direction, the transmission unit 1 is made smaller in the axial direction.

In the transmission unit 1, the solenoid portion 205 of the linear solenoid valve 203 is disposed outside the small valve body 201, so there is a concern that the coil and the like provided in the solenoid portion 205 may be oxidized. In order to eliminate this concern, at least when the unit case 3 is stationary, a sufficient amount of oil is added so that the liquid level of the oil collected at the bottom of the unit case 3 is located above the solenoid part 205 and the solenoid part 205 is immersed in the oil. Oil is sealed inside the unit case 3. Further, the transmission unit 1 may be mounted on a vehicle in an inclined state such that the axial direction is located lower toward the rear. Therefore, a portion of the clutch plate 139 and clutch disc 153 of the 4WD clutch 115 may be submerged in oil. When clutch plate 139 and clutch disc 153 are immersed in oil, the oil acts as resistance to rotation of clutch plate 139 and clutch disc 153, leading to increased energy loss and deterioration of fuel efficiency. Further, the oil is agitated by the rotation of the clutch plate 139 and the clutch disc 153, and the oil bubbles, which may cause air trapping in the oil pump 45.

Therefore, an oil separator 221 is provided between the 4WD clutch 115 and the small valve body 201 so as to cover the lower part of the 4WD clutch 115. The oil separator 221 is formed by abutting a separator body 222 and an abutment rib 223 against each other. The separator main body 222 is fixed to the third transmission case 13, is inclined so as to be positioned lower toward the rear, and has a substantially semicircular shape when viewed in the axial direction. The abutment rib 223 is formed integrally with the first transfer case 14 and has a plate shape that protrudes from the inner surface of the first transfer case 14 . The abutment rib 223 is curved along the arcuate lower end of the separator body 222. By setting the oil separator 221, the 4WD clutch 115 is isolated from the oil that accumulates at the bottom of the unit case 3.

<Power transmission path>
FIG. 3 is a skeleton diagram schematically showing the configuration of the CVT 5 and the transfer 6. As shown in FIG.

When the vehicle moves forward, the forward clutch 83 is engaged and the reverse clutch 92 is released. Power input from the engine 2 to the input shaft 41 via the torque converter 4 is transmitted from the input shaft gear 81 to the primary shaft 54 via the primary input gear 82 by engagement of the forward clutch 83. On the other hand, even if the power input to the input shaft 41 is transmitted from the input shaft gear 81 to the secondary input gear 91 and the secondary input gear 91 rotates, the release of the reverse clutch 92 causes the secondary input gear 91 to rotate to the secondary shaft 55. (The secondary shaft 55) rotates idly, and no power is transmitted to the secondary shaft 55.

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

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

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

A vehicle equipped with the transmission unit 1 can be switched between a two-wheel drive state using left and right rear wheels and a four-wheel drive state using left and right front wheels and rear wheels.

When the 4WD clutch 115 is released, the power (rotation) of the output shaft 43 is not transmitted to the first sprocket 112 and is not transmitted to the transmission shaft 111, as described above. On the other hand, the power of the output shaft 43 is transmitted to the propeller shaft, and from the propeller shaft to the left and right rear wheels via the rear differential gear and the drive shaft. As a result, the left and right rear wheels become driving wheels, and the vehicle runs in a two-wheel drive state.

On the other hand, when the 4WD clutch 115 is engaged, as described above, the power of the output shaft 43 is transmitted to the first sprocket 112, and the first sprocket 112 rotates. The rotation (power) of the first sprocket 112 is transmitted to the second sprocket 113 via the chain 114. As a result, the second sprocket 113 rotates in the same direction as the first sprocket 112, and the transmission shaft 111 rotates together with the second sprocket 113. The rotation of the transmission shaft 111 is transmitted to the left and right front wheels via a front differential gear and a drive shaft. On the other hand, the power of the output shaft 43 is transmitted to the propeller shaft, and from the propeller shaft to the left and right rear wheels via the rear differential gear and the drive shaft. As a result, all the left and right front wheels and rear wheels become drive wheels, and the vehicle runs in a four-wheel drive state.

<Effect>
As described above, when the 4WD clutch 115 is released, power is transmitted from the output shaft 43 to the rear wheels, which are the main drive wheels, but since power is not transmitted from the output shaft 43 to the first sprocket 112, the power is transmitted to the transmission shaft 111. No power is transmitted to the front wheels, which are auxiliary drive wheels. At this time, the vehicle is in a two-wheel drive state using the left and right rear wheels. On the other hand, when the 4WD clutch 115 is engaged, power is transmitted from the output shaft 43 to the rear wheels, and power is also transmitted from the output shaft 43 to the transmission mechanism, so that power is transmitted to the transmission shaft 111 and the transmission shaft Power is transmitted from 111 to the front wheels. At this time, the vehicle is in a four-wheel drive state using the left and right rear wheels and the front wheels.

An axial oil passage 214 is formed along the axial center of the output shaft 43 . The shaft center oil passage 214 is used as an oil passage through which oil for lubrication around the output shaft 43 flows. Further, a cylindrical member 135 is externally fitted and fixed to the output shaft 43, and a clutch pressure supply oil passage 211, which is a circumferential oil passage, is formed between the cylindrical member 135 and the output shaft 43. ing. The clutch pressure supply oil passage 211 is used as an oil passage through which oil for engaging the 4WD clutch 115 flows. Therefore, it is not necessary to form an oil passage in the output shaft 43 through which oil for engaging the 4WD clutch 115 flows.

For example, two oil passages extending in the axial direction are formed in the output shaft 43, one oil passage is used as an oil passage through which oil for lubrication around the output shaft 43 flows, and the other oil passage is A conceivable structure is to use this as an oil passage through which oil for engaging the 4WD clutch 115 flows. However, in this structure, the diameter (hole diameter) of each oil passage becomes small, making processing for forming the oil passage difficult. Further, oil passages for guiding oil from each oil passage to the outer circumferential surface of the output shaft 43 are also required, and the number of processes required to form these oil passages increases. Therefore, productivity is poor.

On the other hand, in the structure in which the axial oil passage 214 and the clutch pressure supply oil passage 211 are formed, the axial oil passage 214 is one oil passage that extends in the axial direction inside the output shaft 43, and there are two oil passages. Since there is no need to form a passage, the diameter of the axial oil passage 214 is not limited to a small diameter. Therefore, processing for forming the axial oil passage 214 in the output shaft 43 is easy. Further, since the number of distribution oil passages 215, 216 for guiding oil from the inside of the output shaft 43 to the outer circumferential surface can be reduced, the number of processes required to form the distribution oil passages 215, 216 is small. Furthermore, forming the clutch pressure supply oil passage 211 does not require drilling of the output shaft 43.

Therefore, in the above-described configuration, it is easy to form the shaft center oil passage 214 and the clutch pressure supply oil passage 211, and the productivity of the transmission unit 1 that transmits power to the rear wheels and the front wheels is excellent.

Further, the second oil passage forming portion 164 of the adapter case 162 is connected to the cylindrical member 135 via a connecting member 181. A small valve body 201 is supported by the adapter case 162. The small valve body 201 is equipped with a linear solenoid valve 203, and the oil output from the linear solenoid valve 203 flows through the fifth oil passage 186 and the second oil passage formed in the second oil passage forming portion 164 of the adapter case 162. The clutch pressure supply oil passage 211 is supplied through the four oil passages 185 and the first communication passage 212 formed in the cylindrical member 135. Therefore, the path from when the pressure of oil for engaging the 4WD clutch 115 is regulated by the linear solenoid valve 203 until it is supplied to the 4WD clutch 115 is shortened. As a result, loss of the clutch pressure supplied to the 4WD clutch 115 on the supply path can be suppressed, and responsiveness of changes in the engagement state of the 4WD clutch 115 to changes in clutch pressure can be improved.

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

For example, in the embodiment described above, the small valve body 201 is provided with the linear solenoid valve 203, and the clutch modulator pressure supplied to the small valve body 201 is regulated to the clutch pressure by the linear solenoid valve 203. The small valve body 201 is not limited to its configuration, and may have a configuration in which a shift valve that selectively outputs the clutch modulator pressure and the hydraulic pressure regulated by the linear solenoid valve 203 is added. Further, the small valve body 201 may be supplied with line pressure output from the valve body 191. In this case, the small valve body 201 may have a configuration in which the line pressure is regulated with the linear solenoid valve 203, or a modulator valve that regulates the line pressure may be further added, and the hydraulic pressure regulated by the modulator valve may be added. A configuration may be adopted in which the input signal is input to the linear solenoid valve 203.

Further, in the above-described embodiment, the transmission unit 1 installed in an FR-based 4WD vehicle was taken up as an example of the power transmission device according to the present invention, but the present invention also deals with the transmission unit 1 mounted on an FR-based 4WD vehicle. It can also be applied to a power transmission device mounted on a part-time 4WD vehicle. Further, the present invention may be applied to a power transmission device mounted on a part-time 4WD vehicle based on RR (rear engine/rear drive).

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

1: Speed change unit (oil supply structure)
6: Transfer (transmission mechanism)
43: Output shaft (first transmission shaft)
111: Transmission shaft (second transmission shaft)
115: 4WD clutch (clutch)
162: Adapter case 185: 4th oil passage (adapter case oil passage)
186: 5th oil passage (adapter case oil passage)
191: Valve body (main valve body)
201: Small valve body (sub valve body)
211: Clutch pressure supply oil passage (circumferential oil passage)
214: Axial oil path

Claims (2)

An oil supply structure applied to a vehicle equipped with left and right main drive wheels and left and right auxiliary drive wheels,
a first transmission shaft that transmits power to the main drive wheels;
a second transmission shaft that transmits power to the sub-drive wheels;
a transmission mechanism that transmits power between the first transmission shaft and the second transmission shaft;
a clutch that is engaged/released to transmit/cut off the power of the first transmission shaft to/from the transmission mechanism;
a cylindrical member externally fitted and fixed to the first transmission shaft;
A main valve body that regulates and outputs hydraulic pressure,
an adapter case connected to the cylindrical member;
a sub-valve body that is supported by the adapter case and adjusts and outputs the hydraulic pressure output from the main valve body as necessary;
An axial oil passage is formed along the axial center of the first transmission shaft, through which oil flows for lubrication around the first transmission shaft,
A circumferential oil passage through which oil for engagement of the clutch flows is formed between the first transmission shaft and the cylindrical member,
The adapter case is formed with an adapter case oil passage that communicates with the circumferential oil passage and is supplied with oil output from the sub-valve body ,
The adapter case is connected to the cylindrical member from an outer peripheral side of the cylindrical member,
The sub-valve body is arranged in a space between the adapter case and the clutch, and a part of the sub-valve body overlaps with the clutch in the axial direction of the first transmission shaft . The oil supply structure according to claim 1 , wherein an oil separator is provided between the clutch and the sub-valve body so as to cover a lower part of the clutch.

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