JP2007154915A - Travelling power transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a troublesome shift operation of a gear type transmission, in a travelling power transmission system interposed between a motor and an axle and having a belt-type automatic continuously variable transmission and a gear type transmission. <P>SOLUTION: The gear type transmission 50 is provided with a first gear row 50H in which first clutches 71, 73 engaged when the number of revolution of the input part is a predetermined value or more, and a second gear row 50L engaged when the first clutch is not engaged, are interposed between an input part receiving power from the belt-type automatic continuously variable transmission 40, and an output part output the power to the axle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a traveling power transmission device that is mainly used for a work vehicle such as a transport vehicle and is interposed between a prime mover and an axle, and includes a belt-type automatic continuously variable transmission and the belt-type automatic continuously variable transmission. The present invention relates to a travel power transmission device including a transmission mechanism such as a gear-type transmission driven by a transmission.

  2. Description of the Related Art Conventionally, a traveling power transmission device is provided with a belt type automatic continuously variable transmission (hereinafter referred to as “CVT”) as a main transmission and a gear type transmission as an auxiliary transmission between a prime mover and an axle. For example, Patent Document 1 discloses a vehicle structure to which such a traveling power transmission device is applied.

JP 2003-194097 A

  However, if the speed change operation of the auxiliary transmission is manual, the operation must be basically performed while the vehicle is stopped, and it is complicated, and if it is operated incorrectly during traveling, the motor side or axle side at that time If the speed stage is unbalanced with the number of rotations, there is a possibility that the transmission efficiency may be reduced or the engine stalled due to insufficient torque.

  Conventionally, when the motor speed is in the idle speed range, the belt tension of the CVT is set to 0 so that the neutral state is automatically displayed. However, it is difficult to travel at a low speed when traveling on a slope. It becomes. Further, since the start is made by slipping the belt, the life of the belt is relatively short and the number of times of maintenance is large. If a belt-type automatic continuously variable transmission is set so that tension can be maintained in the idling speed range, it will be possible to run at a low speed and the belt life will be extended, but how to automatically show a neutral state is a problem Become.

  Further, in a traveling power unit equipped with a conventional CVT, the CVT is provided with an output shaft of a prime mover arranged in parallel and an input shaft of a transmission mechanism (gear type transmission) on the transmission downstream side of the CVT as a pulley shaft, The CVT dustproof / waterproof CVT case also functions as a connecting member for connecting the prime mover and the transmission case that houses the transmission mechanism, but there are several specifications for the prime mover (for example, anti-vibration mounts). If there is something you don't do, a diesel engine, a gasoline engine, or a difference in horsepower, you'll have to prepare several CVT cases that are designed for each of them, resulting in high costs.

  If the CVT and CVT case are made independent of the prime mover and placed at a position unrelated to the change in the kind of prime mover, the single CVT case can be solved, and this problem can be solved. It is important to secure a space where the input means to the CVT corresponding to the type can be freely designed in the traveling power transmission device.

  First, a first object of the present invention is a traveling power transmission apparatus having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle. It is possible.

  In order to achieve this first object, according to the present invention, as described in claim 1, a traveling power transmission having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle. In the device, the rotational speed of the input unit is set between an input unit that receives power from the belt-type automatic continuously variable transmission and an output unit that outputs power to the axle. The first gear train that includes the first clutch that engages when the value is greater than or equal to the value is different from the first gear train that includes the second clutch that engages when the first clutch is not engaged. And a second gear train having a reduction ratio.

  Further, in the configuration as described in claim 1, as described in claim 2, the first gear train is a high-speed gear train and the second gear train is a low-speed gear train.

  Further, in the configuration as described in claim 1 or 2, as described in claim 3, the first clutch is a centrifugal clutch.

  Alternatively, in the configuration as described in claim 1 or 2, as described in claim 4, the first clutch is a hydraulic clutch.

  Further, in the configuration as described in any one of claims 1 to 4, as described in claim 5, the second clutch is an overrunning clutch.

  Alternatively, in the configuration as described in any one of claims 1 to 4, as described in claim 6, the second clutch is a hydraulic clutch.

  Alternatively, in the configuration as described in any one of claims 1 to 4, as described in claim 7, the second clutch is a dog clutch.

  Further, in the configuration according to any one of claims 1 to 7, as described in claim 8, the idle transmission is separated from the transmission upstream side of the gear-type transmission in the idle speed range of the prime mover. A centrifugal clutch is provided that engages when exceeding several ranges.

  Further, in the configuration as described in claim 8, as described in claim 9, when the rotation on the driving side of the centrifugal clutch becomes lower than the rotation on the driven side, the centrifugal clutch is engaged to bypass the centrifugal clutch. Overrunning clutch that transmits power.

  Further, in the configuration according to claim 8 or 9, as described in claim 10, an adjustment gear train for adjusting the input rotational speed from the prime mover is arranged on the transmission upstream side of the belt type automatic continuously variable transmission. Has been established.

  Further, in the configuration as described in claim 10, as in claim 11, the centrifugal clutch is interposed between the adjustment gear train and the belt type automatic continuously variable transmission.

  Alternatively, in the configuration as described in claim 10, as described in claim 12, the centrifugal clutch is interposed between the belt-type automatic continuously variable transmission and the gear-type transmission.

  Further, in the configuration according to any one of claims 1 to 12, as in claim 13, the belt type automatic continuously variable transmission is disposed on the opposite side of the prime mover with the gear type transmission interposed therebetween. ing.

  Further, in the configuration according to any one of claims 1 to 12, as described in claim 14, the switching point between the first gear train and the second gear train is set to 1 / the maximum speed of the vehicle. An area slower than 2 is set.

  Further, in the configuration according to any one of claims 1 to 14, as described in claim 15, the gear-type transmission includes the first and second clutches with respect to the output unit without the first and second clutches. A third gear train capable of selectively outputting rotations having different rotation directions from the one gear train and the second gear train; and a third clutch interposed in the third gear train. .

  Further, in the configuration as claimed in claim 15, as described in claim 16, the third gear train is a reduction gear that is larger than the reduction ratio on the high speed side of either the first gear train or the second gear train. The ratio is set.

  Further, in the configuration as described in claim 13, as described in claim 17, the gear type transmission supports the belt type automatic continuously variable transmission and is mounted in an anti-vibration manner on the frame of the vehicle.

  Further, in the configuration as set forth in claim 13 or 17, as described in claim 18, the belt-type automatic continuously variable transmission is covered with a cover.

  A second object of the present invention is a traveling power transmission device having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle. It is to make it possible to automatically show the neutral state while making it possible.

  In order to achieve the second object, according to the present invention, as described in claim 19, a traveling power transmission having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle. In the device, a centrifugal clutch is provided on the upstream side of transmission of the gear type transmission so as to be separated in an idle speed range of the prime mover and to be engaged when the idle speed range is exceeded.

  Further, in the configuration as described in claim 19, as described in claim 20, when the rotation on the driving side of the centrifugal clutch becomes lower than the rotation on the driven side, the centrifugal clutch is engaged to bypass the centrifugal clutch. Overrunning clutch that transmits power.

  Further, in the configuration as set forth in claim 19, as described in claim 21, a gear train for adjusting the input rotational speed from the prime mover is disposed on the transmission upstream side of the belt type automatic continuously variable transmission. Yes.

  Further, in the configuration as described in claim 19, as described in claim 22, the centrifugal clutch is interposed between the gear train and the belt type automatic continuously variable transmission.

  Alternatively, in the configuration as described in claim 19, as described in claim 23, the centrifugal clutch is interposed between the belt type automatic continuously variable transmission and the gear type transmission.

  A third object of the present invention is to drive a belt-type automatic continuously variable transmission and the belt-type automatic continuously variable transmission to transmit power to a front axle and a rear axle arranged in front and rear of the vehicle. A driving power transmission device provided with a transmission mechanism, wherein the power is input to the belt-type automatic continuously variable transmission from a prime mover disposed between the front axle and the rear axle. The storage structure of the automatic continuously variable transmission can be unified regardless of changes in the specifications of the prime mover, thereby reducing the cost.

  In order to achieve this third object, according to the present invention, as described in claim 24, a belt type automatic continuously variable transmission for transmitting power to a front axle and a rear axle arranged in front of and behind the vehicle, A driving power transmission device comprising a transmission mechanism driven by a belt type automatic continuously variable transmission, wherein the belt type automatic continuously variable transmission is moved from a prime mover disposed between the front axle and the rear axle. In the structure for inputting power, the traveling power transmission device is disposed on one of the front and rear sides of the prime mover, and a belt type automatic continuously variable transmission on the opposite side of the prime mover in a case housing the transmission mechanism And an input means for transmitting the output of the prime mover to the belt type automatic continuously variable transmission so as to penetrate the front and rear surfaces of the case of the transmission mechanism.

  Further, in the configuration as set forth in claim 24, as described in claim 25, the belt-type automatic continuously variable transmission is covered with a cover.

  Further, in the configuration as described in claim 24, as described in claim 26, the transmission mechanism in the traveling power transmission device includes a front output shaft that transmits power to the front axle, and a rear axle. A rear output shaft that transmits power, and either a transmission shaft that connects the front output shaft to the front axle or a transmission shaft that connects the rear output shaft to the rear axle, It is arranged on one side.

  Further, in the configuration as described in claim 24, as described in claim 27, in the case of the transmission mechanism, the input means is provided with an adjustment gear train for adjusting the input rotational speed from the prime mover. Yes.

  First, the present invention provides a traveling power transmission device having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle. The first clutch is automatically engaged / separated by a change in the rotational speed of the input section of the transmission, and the second clutch is automatically separated / engaged accordingly, respectively by the first gear train and the second gear train. The speed reduction ratio that appears is automatically selected.

  According to the second aspect of the present invention, the gear type transmission is automatically switched between the high and low speed stages, so that a complicated shifting operation can be omitted, and according to the traveling state. A reliable speed stage setting is made.

  Further, by configuring as described in claim 3 or 4, it is possible to configure a first clutch that is engaged / separated in accordance with a change in the rotational speed.

  Further, by configuring as in any one of claims 5 to 7, a second clutch that is separated / engaged in conjunction with engagement / separation of the first clutch is formed, and the first gear train and the second gear It is possible to automatically select the reduction gear ratio that appears by each of the gear trains.

  Further, by configuring as in any one of claims 8 to 12, in the traveling power transmission apparatus in which the gear type transmission is configured as described in claim 1, each of claims 19 to 23 described later is provided. The effect by the structure as described can be produced.

  Further, with the construction as described in claim 13, the storage structure of the belt type automatic continuously variable transmission can be unified and the cost can be reduced regardless of the change in the specifications of the prime mover.

  Further, by configuring as described in claim 14, traveling by the first gear train is mainly performed, and traveling by the second gear train can be set according to a less frequent situation (for emergency).

  Further, by configuring as described in claim 15, it is possible to select one of the two different rotational directions as the output rotational direction to the two axles, and the vehicle can be switched forward and backward.

  Further, according to the structure of the sixteenth aspect, the traveling by the third gear train is performed more efficiently in the low speed region than the traveling by the gear train on the high speed side of the first gear train and the second gear train.

  Further, by configuring as described in claim 17, it is possible to prevent problems caused by vibration in the gear type transmission and the belt type automatic continuously variable transmission in the traveling power transmission device.

  Further, the belt-type automatic continuously variable transmission can be protected against dust and water by being configured as described in claim 18, and the belt-type automatic continuously variable transmission is sandwiched between the gear-type transmission and the motor. The belt-type automatic continuously variable transmission can be greatly exposed by opening the cover in combination with being located on the opposite side, and is excellent in maintainability. Regardless of changes in the specifications of the prime mover, only one type of cover can be used for the belt type automatic continuously variable transmission.

  Next, the present invention provides a traveling power transmission apparatus having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle. When the prime mover is idling, the centrifugal clutch is disengaged, so that a neutral state can be obtained.This allows the belt-type automatic continuously variable transmission to be set to always maintain tension and transmit power. If the prime mover rotational speed exceeds the idle rotational speed even a little, the centrifugal clutch can be made to travel at a low speed.

  Further, when the driven side rotational speed is higher than the driving side rotational speed due to a downhill or the like, the overrunning clutch is engaged. By avoiding the centrifugal clutch, power transmission to the gear type transmission is ensured via the overrunning clutch, and the engine brake can be effectively operated.

  Further, by configuring as described in claim 21, for example, when selecting either a gasoline engine having a high rotational speed or a diesel engine having a low rotational speed and applying it as a prime mover, the rotational speed as a prime mover. Even when different settings are used, the input rotational speed to the belt-type automatic continuously variable transmission can be kept substantially constant.

  According to the twenty-second aspect of the present invention, the belt-type automatic continuously variable transmission, the gear-type transmission on the downstream side of the transmission, and the axle can be brought into a neutral state during idle rotation of the prime mover.

  Alternatively, by configuring as in the twenty-third aspect, at the time of idle rotation of the prime mover, even if the belt-type automatic continuously variable transmission is in a driving state, the gear-type transmission and the axle can be neutralized. .

  The present invention also includes a belt-type automatic continuously variable transmission and a transmission mechanism driven by the belt-type automatic continuously variable transmission for transmitting power to a front axle and a rear axle arranged at the front and rear of the vehicle. 25. A travel power transmission device comprising: a power input from a prime mover disposed between the front axle and the rear axle to the belt-type automatic continuously variable transmission. By configuring, the storage structure of the belt type automatic continuously variable transmission can be unified regardless of the change in the specifications of the prime mover, and the cost can be reduced. On the other hand, the input means to the belt-type automatic continuously variable transmission for inputting power from the prime mover is supported by penetrating the front and rear surfaces of the case of the transmission mechanism. The space to design freely according to the specifications can be secured.

  Further, the belt-type automatic continuously variable transmission can be protected against dust and water by being configured as described in claim 25, and the belt-type automatic continuously variable transmission sandwiches the gear-type transmission. The belt-type automatic continuously variable transmission can be greatly exposed by opening the cover in combination with being located on the opposite side, and is excellent in maintainability. Regardless of changes in the specifications of the prime mover, only one type of cover can be used for the belt type automatic continuously variable transmission.

  Further, by configuring as described in claim 26, it is possible to avoid interference between the transmission shaft and the prime mover, and it is not necessary to largely shift the prime mover and the front and rear output shafts up and down. Can be secured.

  Further, according to the structure described in claim 27, coupled with the fact that the free design space of the input means is secured in the case of the transmission mechanism as described above, for example, the rotational speed can be obtained using the adjustment gear train. The belt type automatic continuously variable transmission can be used even when using a motor with a different engine speed setting, such as selecting either a gasoline engine with a high speed or a diesel engine with a low speed to apply as a motor. It is possible to keep the input rotational speed to approximately constant.

  1 and 2 show an overall view of a work vehicle (transport vehicle) equipped with an automatic transmission according to the present invention. The schematic structure of this transport vehicle will be described.

  A platform 100b is configured on the body frame 100 of the transport vehicle, and a front cover 100a is mounted in front of the platform 100b. A steering handle 101 for steering the front wheels 104 and 104 is provided above the front cover 100a. Has been. The rear part of the body frame 100 is one step higher than the platform 100b, and a driver's seat 102 is mounted on the front end upper part and a loading platform 103 is mounted on the rear side.

  The fuselage frame 100 elastically supports (vibration mount) an engine (prime mover) 1 via an anti-vibration rubber (not shown) below the loading platform 103, and a sub-shift in front of the prime mover 1. Like the engine 1, the transmission case 3 that houses the gear-type gearbox is elastically supported (anti-vibration mount) via an anti-vibration rubber (not shown). A CVT case 2 is integrally formed on the front surface of the transmission case 3, and houses a belt type automatic continuously variable transmission (CVT) as a main transmission. The mission case 3 and the CVT case 2 are below the driver's seat 102 as shown in FIG. 1, and the mission case 3 and the CVT case 2 are externally provided for maintenance and the like by enabling the driver's seat 102 to be rotated forward. It is preferable that exposure is possible.

  An engine output shaft 1a protrudes horizontally from the prime mover 1 and a flywheel 1b is provided at the front end thereof. The rear end of the input shaft 4 that protrudes horizontally rearward from the transmission case 3 is connected to the universal joint 4a. And it is connected to the flywheel 1b via the transmission shaft 1c, and the power of the prime mover 1 is transmitted to the input shaft 4.

  At the lower part of the transmission case 3, a rear output shaft 5 protrudes horizontally behind, and a front output shaft 6 protrudes horizontally on the same axis as the rear output shaft 5. The input means to the CVT including the input shaft 4 passes through the mission case 3 forward and is drivingly connected to the CVT in the CVT case 2, and the output of the CVT is a gear-type speed change in the mission case 3. It is transmitted to the front and rear output shafts 5 and 6 via the machine. The gear type transmission has a forward / reverse switching function, and the drive direction of the output shafts 5 and 6 can be switched between a forward direction and a reverse direction.

  Thus, the CVT is arranged on the opposite side of the engine 1 with the mission case 3 interposed therebetween. This makes it possible to unify the design of the CVT case 2 regardless of the multi-specification of the prime mover 1, and the CVT including the input shaft 4 corresponding to each specification of the prime mover 1 in the mission case 3. It is possible to secure a free design space for the input means and the gear type transmission.

  The fuselage frame 100 supports a rear axle housing 10 behind the prime mover 1, and the rear axle housing 10 supports a pair of left and right rear axles 12 and 12, and supports both rear axles 12 and 12. The differential gear mechanism 11 to be differentially connected is housed. Each rear axle 12 is drivingly connected to each front wheel 104 via universal joints 13 and 13 and a transmission shaft 14 as shown in FIG. 2, and a suspension 16 (coil spring, air) is connected to each front wheel 104 from the fuselage frame 1. The rear axle housing 10 is supported so as to be vertically movable relative to the left and right front wheels 104.

  An input shaft 11a of a differential gear mechanism 11 is projected horizontally from the rear axle housing 10, and the rear output shaft 5 and the input shaft 11a are connected by universal joints 7a and 7b and a transmission shaft 7, The output of the gear type transmission in the mission case 3 is transmitted to both rear wheels 105. The rear transmission shaft 7 is disposed so as to pass through the left and right sides of the prime mover 1 to avoid interference with the prime mover 1 using the universal joints 7a and 7b.

  Further, the fuselage frame 100 supports a front axle housing 16 below the front cover 100a. The front axle housing 16 supports a pair of left and right front axles 18 and 18 and both front axles 18. -The differential gear mechanism 17 which differentially connects 18 is accommodated. Each front axle 18 is drivingly connected to each front wheel 104 via universal joints 19 and 19 and a transmission shaft 20 as shown in FIG. 2, and a suspension 21 (coil spring, air) is connected to each front wheel 104 from the body frame 1. The front axle housing 16 is supported so as to be movable relative to the left and right front wheels 104.

  An input shaft 17a of the differential gear mechanism 17 projects horizontally from the front axle housing 16, and the front output shaft 6 and the input shaft 17a are connected by the universal joints 8a and 8b and the transmission shaft 8, The output of the gear type transmission in the mission case 3 is transmitted to both front wheels 104 and 104. When the transmission case 3 is arranged behind the prime mover 1, the transmission shaft 8 is arranged so as to pass through one side of the prime mover 1 in order to avoid interference with the prime mover 1.

  Each front wheel 104 is connected to each front axle 18 so as to be steerable. Both front wheels 104 and 104 are connected to each other by a tie rod 9, and the tie rod 9 is operatively connected to the steering handle 101. Thus, the vehicle is steered by turning the front wheels 104 and 104 to the left and right by the turning operation of the steering handle 101.

  Furthermore, operation tools (lever, pedal, etc.) such as a forward / reverse switching operation tool and a brake operation tool (not shown) are arranged on the fuselage frame 100 so that a driver sitting in the driver's seat 102 can operate. .

  Each embodiment of the power transmission structure from the input shaft 4 to the output shafts 5 and 6 configured in the CVT case 2 and the mission case 3 integrally formed in FIGS. 3 to 10 will be described. To do.

  First, as a structure common to all the embodiments of FIGS. 3 to 12, the CVT case 2 and the transmission case 3 are formed by joining the front case portion 22a, the middle case portion 22b, and the rear case portion 22c in the front and rear directions. Composed. More specifically, the middle case portion 22b has a vertical partition wall 22d in the middle of the front and rear, and a front open internal space in front of the partition wall 22d is defined as a rear space of the CVT case 2, and from the partition wall 22d. The rear, rear-open internal space is used as a front space of the mission case 3, and the CVT case that houses the CVT 40 is formed by joining the open rear end of the front case portion 22a to the front open end of the middle case portion 22b. The transmission case 3 that houses the gear type transmission 50 and the like is configured by joining the opening front end of the rear case portion 22c to the opening rear end of the middle case portion 22b. In addition, it is preferable that joining of case parts is detachable by bolt fastening etc.

  Further, the joint surface between the front case portion 22a and the middle case portion 22b of the CVT case 2 is brought close to the rear side of the CVT 40, that is, the partition wall 22d on the mission case 3 side, and the front case portion 22a is connected to the entire CVT 40. When the front case portion 22a is removed from the middle case 22b, the substantially entire circumference other than the rear surface of the CVT 40 is exposed, which is preferable for maintenance such as belt replacement of the CVT 40.

  At the rear part of the transmission case 3 constituted by the middle case part 22b and the rear case part 22c, the front part of the input shaft 4 is inserted and supported by the bearing part 22e from the rear, and is parallel to the input shaft 4. A transmission shaft 23 in the front-rear direction is supported. The transmission shaft 23 has a rear end supported by the rear wall of the transmission case 3 (rear case portion 22 c) and is drivingly connected to an input pulley 41 of a CVT 40 housed in the CVT case 2.

  Further, the transmission shaft 23 is drivingly connected to the input shaft 4 via the adjustment gear train 30 in the mission case 3. That is, the input means to the CVT 40 includes the input shaft 4, the adjustment gear train 30, and the transmission shaft 23. 3 to 7, the gear 31 fixed to the input shaft 4 and the gear 32 fixed to the transmission shaft 23 are engaged with each other.

  Even when a motor 1 having a different rotational speed setting is used as the prime mover 1 (for example, a diesel engine having a low rotational speed and a gasoline engine having a high rotational speed), the gears of the adjustment gear train 30 can be changed by means such as changing the gear diameter or the number of gears. By adjusting the ratio, the input rotation speed of the CVT 40, that is, the rotation speed of the transmission shaft 23 can be made substantially constant. Thus, by providing the adjustment gear train 30 between the CVT 40 and the prime mover 1, even when the rotational speed setting of the prime mover is different, the input rotational speed of the CVT 40 can be easily adjusted by the gear adjustment of the adjustment gear train 30. Therefore, it is not necessary to replace with a CVT or a gear type transmission having a different setting in accordance with a change in the setting of the prime mover, which contributes to cost reduction.

  The CVT 40 housed in the CVT case 2 includes an input pulley 41 whose rotational shaft is drivingly connected to the transmission shaft 23, and an output pulley 42 which is drivingly connected to the speed change driving shaft 25 of the gear type transmission 50 described later. A V-belt 43 is interposed therebetween. Further, a torque cam 44 for load control is interposed between the output pulley 42 and the speed change drive shaft 25, and an output subjected to speed change control by the CVT 40 according to the traveling load is transmitted to the speed change drive shaft 25.

  The input pulley 41 is a split pulley, and the belt winding groove width changes with the rotational speed of the transmission shaft 23 (that is, the output rotational speed of the prime mover 1). Along with this, the V-belt 43 moves to change the speed ratio between the input pulley 41 and the output pulley 42. As the rotational speed is lower, the groove width of the input pulley 41 becomes wider and the input / output speed ratio is reduced. In this embodiment, even if the rotational speed of the prime mover 1 is in the idle rotational speed range, the speed ratio is reduced. 0 (for example, 0.75), that is, the tension of the V belt 43 is maintained without making the CVT 40 neutral, and a slight driving force is transmitted to the output pulley 42 to prevent the belt 43 from slipping. The life of the belt 43 is improved.

  On the other hand, in order to ensure a neutral state during idle rotation of the prime mover 1, the centrifugal clutch 70 is arranged on the transmission upstream side of the gear type transmission 50 described later. 3, 5, and 7, the pulley shaft 41 a is pivotally supported in the CVT case 2 as the rotation shaft of the input pulley 41, and the rear end protrudes rearward from the partition wall 22 d. The centrifugal clutch 70 is interposed between the pulley shaft 41a and the front end of the transmission shaft 23. That is, it is interposed between the prime mover 1 and the CVT 40. 4 and 6, the centrifugal pulley 70 is interposed between the CVT 40 and the gear-type transmission 50, and the pulley shaft 42a is used as the rotating shaft of the output pulley 42 in the CVT case. 2 is supported in the front-rear direction, the rear end of the pulley shaft 42a protrudes rearward from the partition wall 22d, and the front end of the speed change drive shaft 25 is supported by a bearing 22g provided in the transmission case 30. Further, it is connected via a centrifugal clutch 70.

  3, 5, and 7, the speed change drive shaft 25 not provided with the centrifugal clutch 70 extends forward, penetrates the partition wall 22 d, and serves as a pulley shaft of the output pulley 42 as a CVT case. 4 and 6, in each of the embodiments shown in FIGS. 4 and 6, the output shaft 23 without the centrifugal clutch 70 extends forward, penetrates the partition wall 22d, and is input pulley. The pulley shaft 41 is supported in the CVT case 2.

  The centrifugal clutch 70 includes a drive member 70a on the transmission upstream side having a weight 70b and a driven member 70c on the lower transmission side, and the weight 70b opens in the centrifugal direction by centrifugal force as the rotational speed of the drive member 70a increases. The clutch is engaged with the driven member 70c by pressure. By setting the rotation speed of the prime mover 1 corresponding to the engagement / separation timing of the clutch 70 to the maximum value of the idle rotation speed, a neutral state at the time of idle rotation can be secured.

  3, 5, and 7, the driving member 70 a is fixed to the transmission shaft 23, and the driven member 70 c is fixed to the pulley shaft 41 a. The transmission system will be neutral. 4 and 6, the drive member 70a is fixed to the pulley shaft 42a and the driven member 70c is fixed to the speed change drive shaft 25. When the centrifugal clutch 70 is separated, the CVT 40 can be driven. In this state, the transmission system after the gear type transmission 50 is set to the neutral state.

  5 and 6, the overrunning clutch is provided between the pulley shaft 41a and the transmission shaft 23 or between the pulley shaft 42a and the transmission drive shaft 25 so that the centrifugal clutch 70 can be bypassed. 70d is interposed. When the rotational speed of the driven side (pulley shaft 41a or transmission drive shaft 25) is higher than the drive side rotational speed (transmission shaft 23 or pulley shaft 42a) due to downhill or the like, the overrunning clutch 70d is engaged. Thus, the reverse torque is transmitted from the gear-type transmission 50 to the prime mover 1 via the CVT 40 by bypassing the centrifugal clutch 70 and the overrunning clutch 70d, and the engine brake can be effectively applied. it can.

  The transmission case 3 accommodates the input means (the transmission shaft 23 and the adjustment gear train 30) to the CVT 40 including the input shaft 4 as described above, and further serves as a sub-transmission driven by receiving power shifted by the CVT 40. And a center differential gear mechanism 60 that is driven by the output of the gear transmission 50 and differentially connects the front and rear output shafts 5 and 6 is housed.

  Of the configuration of the transmission mechanism in the transmission case 3, each embodiment of the gear type transmission 50 shown in FIGS. 3 to 10 will be described. First, as a common structure of these embodiments, a forward high-speed drive gear 25a, a forward low-speed drive gear 25b, and a reverse drive gear 25c are connected to a speed change drive shaft 25 that is supported in the longitudinal direction in the mission case 30. It is installed.

  The forward high-speed drive gear 25a meshes with the forward high-speed driven gear 51 to constitute a forward high-speed gear train 50H, and the forward low-speed drive gear 25b meshes with the forward low-speed driven gear 52 to constitute a reverse low-speed gear train 50L. The reverse drive gear 25c meshes with the reverse driven gear 55 via an idle gear 57 (not shown in FIGS. 3 to 7; see FIGS. 9 and 10) to constitute a reverse gear train 50R. Any one of these gear trains 50H, 50L, and 50R is selected, and the rotation of the speed change drive shaft 25 is transmitted to the speed change driven shaft 26 having a final pinion 26a meshing with the bull gear 61 of the center differential gear mechanism 60. .

  In the embodiment shown in FIGS. 3 to 6, the clutches of the respective transmission gear trains 50H, 50L, and 50R are provided between the driven gears 51, 52, and 55 and the driven shaft 26 or 27, as will be described later. The gears 25a, 25b, and 25c are provided on the speed change drive shaft 25 so as not to rotate relative to each other. 3 to 6, the forward high speed drive gear 25a is a separate member from the speed change drive shaft 25 and is fixed to the speed change drive shaft 25, and the forward speed low speed drive gear 25b and the reverse drive gear are provided. 25c is formed integrally with the speed change drive shaft 25, but this structure is not limited, and each structure may be formed integrally with the speed change drive shaft 25 even if it is constituted by a separate member. May be.

  In the embodiment of FIG. 7, the forward high-speed gear train 50H has a clutch interposed between the speed change drive shaft 25 and the forward high speed gear 25a as will be described later, so that the forward high speed gear 25a is relative to the speed change drive shaft 25. It is installed in a freely rotatable manner. 9 and FIG. 10, both the forward high-speed gear train 50H and the forward low-speed gear train 50L are interposed between the transmission drive shaft 25 and the drive gears 25a and 25b. Therefore, the forward high-speed drive gear 25a and the forward low-speed drive gear 25b are connected to the transmission drive shaft 25 so as to be relatively rotatable (via a bearing).

  In each of the embodiments shown in FIGS. 3 to 10, the transmission driven shaft 26 is provided with a cylindrical forward driven shaft 27 so as to be relatively rotatable, and the transmission driven shaft 26 is provided immediately before the forward driven shaft 27. The spline hub 53 is fixed, and the reverse driven gear 55 is provided on the transmission driven shaft 26 so as to be relatively rotatable in front of the spline hub 53. A reverse clutch tooth 55 a is formed at the rear end of the reverse driven gear 55 facing the spline hub 53. Then, an appropriate position of the speed change driven shaft 26 (in the embodiments shown in FIGS. 3 to 6, 9 and 10, near the front end of the speed change driven shaft 26 (immediately before the reverse drive gear 55), and in the embodiment shown in FIG. In the vicinity of the rear end of the shaft 26 (behind the forward high-speed gear 25a), the final pinion 26a is integrally formed (another member may be fixed).

  In the embodiment shown in FIGS. 3 to 7, the forward low-speed gear train 50L includes a forward low-speed clutch 72 interposed between the forward low-speed driven gear 52 and the forward driven shaft 27 as described later. A forward clutch member 54 that integrally forms clutch teeth is fixed to the front end of the forward driven shaft 27 facing the rear end of the hub 53. On the other hand, in each embodiment of FIG. 9 and FIG. 10 in which the forward low-speed gear train 50L includes a clutch interposed between the forward low-speed drive gear 25b and the transmission drive shaft 25, the forward high-speed driven gear 51 and the forward low-speed gear Both driven gears 52 are fixed to the forward driven shaft 27, and the forward low speed driven gear 52 is connected to the forward clutch member 54 at the front end of the forward driven shaft 27 facing the rear end of the spline hub 53. A forward clutch tooth 52a is formed in place of the tooth.

  3 to 10, the spline hub 53 is provided with a shifter 56 that is slidable in the axial direction. The shifter 56 is configured to perform the forward / reverse switching operation provided in the vehicle as described above. By the operation of the tool, the neutral position in which the spline is engaged only with the spline hub 53 without being engaged with the clutch teeth (or the clutch teeth 52a) or the reverse clutch teeth 55a of the forward clutch member 54, from the neutral position. The spline hub 53 is slid forward and slid forward from the neutral position when the spline hub 53 is fitted only to the clutch teeth (or forward clutch teeth 52a) of the forward clutch member 54. The position is switched to the reverse position, ie, the reverse position where only the reverse clutch teeth 55a are fitted.

  3 to 7, for the sake of convenience, the state of the spline hub 53 in the neutral position is shown above the speed change driven shaft 26, and the state of the spline hub 53 in the forward position is shown below the speed change driven shaft 26. Yes.

  When the shifter 56 is in the forward movement position, the forward driven shaft 27 is engaged with the speed change driven shaft 26 so as not to be relatively rotatable, and the forward high speed clutch and the forward low speed clutch are automatically engaged / separated as will be described later. Either the gear train 50H or the forward low-speed gear train 50L is drivingly connected to the forward driven shaft 27 to cause the transmission driven shaft 26 to rotate forward. On the other hand, when the shifter 56 is in the reverse drive position, the reverse drive gear 55 is engaged with the speed change driven shaft 26 so as not to be relatively rotatable, and the speed change driven shaft 26 is rotated backward.

  3 to 7, the forward low-speed driven gear 52 is provided around the forward driven shaft 27 via the forward low-speed clutch 72 having an overrunning clutch structure. As shown in FIG. 8 in particular, the forward low speed clutch 72 has a plurality of sprags 72a arranged radially about the axis of the transmission driven shaft 26, and the rotational speed of the forward driven shaft 27 on the lower transmission side. Becomes lower than the forward low-speed gear 52 on the transmission upstream side, the sprag 72a rises, and the forward low-speed gear 52 is engaged with the forward driven shaft 27 in a relatively non-rotatable manner.

  FIG. 8 discloses a rotational speed sensor 82 attached to the mission case 3 (rear case portion 22c), which is described later with reference to FIG. This is used in the embodiment of FIG.

  3, 4, 5, 6, and 7 are gear-type transmissions having a structure in which the forward low-speed clutch 72 is interposed between the forward low-speed driven gear 52 and the forward driven shaft 27 as described above. Three different embodiments of the forward high-speed gear train 50 and the forward high-speed clutch are disclosed. These examples will be described.

  3 and 4, the forward high-speed driven gear 51 is engaged and separated from the forward driven shaft 27 via the forward high-speed clutch 71 having a centrifugal clutch structure. The forward high speed clutch 71 is housed in a clutch case 22f attached to the rear end surface of the rear case portion 22c so as to protrude rearward. The clutch case 22f supports the rear end of the speed change driven shaft 26 via a bearing.

  The centrifugal forward high-speed clutch 71 includes a drive member 71a on the transmission upstream side having a weight 71b and a driven member 71c on the transmission downstream side. As the rotational speed of the drive member 71a increases, the weight 71b is caused by centrifugal force. It opens in the centrifugal direction and is crimped to the driven member 71c to engage the clutch. The drive member 71a is fixed to the forward high-speed driven gear 51, and the driven member 70c is fixed to the forward driven shaft 27.

  The forward high speed clutch 71 is related to the forward low speed clutch 72, which is the above-described overrunning clutch of the shafts 27 and 26, with the rotational speeds of the forward driven shaft 27 and the shift driven shaft 26 starting separation of the forward high speed clutch 71. It is set so as to substantially match the number of rotations to be started. This setting can be made by changing the number of weights 71b, changing to a different weight, or the like.

  Thus, in the state where the shifter 56 is disposed at the forward movement position, during normal traveling, the centrifugal clutch type forward high speed clutch 71 is engaged, while the forward low speed clutch 72, which is an overrunning clutch, is separated, and the forward high speed gear train. Of 50H and forward low-speed gear train 50L, forward high-speed gear train 50H is drivingly connected to forward driven shaft 27 to rotate shift driven shaft 26 forward and at high speed. When the number of revolutions of the forward high-speed driven gear 51 (transmission drive shaft 25) is less than a certain value due to starting or when a traveling load is applied, the forward high-speed clutch 71 is separated while the forward low-speed clutch 72 is separated. Are engaged, the forward low-speed gear train 50L is drivingly connected to the forward driven shaft 27, and the variable speed driven shaft 26 is rotated forward at a low speed.

  3, the centrifugal clutch 70 is provided on the transmission upstream side of the CVT 40, and FIG. 4 is an implementation in which the centrifugal clutch 70 is provided on the transmission downstream side of the CVT 40 (between the CVT 40 and the gear type transmission 50). As an example.

  Here, the driving characteristics in the driving power transmission apparatus of each of the embodiments of FIGS. 3 to 10, that is, the relationship of the driving force (Traction Effect) TE with respect to the vehicle speed (Ground Speed) GS shown in FIG. As a representative, a description will be given based on the control of the clutches 71 and 72 of the traveling power transmission device in each embodiment of FIGS.

  First, in the graph of FIG. 11, the value of the vehicle speed GS assumes that the reverse speed is negative and the forward speed is positive. In FIG. 11, a graph L is a traveling characteristic by the forward low-speed gear train 50 </ b> L obtained by engagement of the forward low-speed clutch 72 (and the shifter 56 is set to the forward position), and a graph H is engagement of the forward high-speed clutch 71 (and The graph R shows the running characteristics of the reverse gear train 50R obtained by engaging the reverse clutch (that is, setting the shifter 56 to the reverse position). To express.

  At the time of forward start (the vehicle speed GS increases from 0), the forward high speed clutch 71 is disengaged, while the forward low speed clutch 72 is engaged, and the transmission at the forward low speed gear train 50L increases as shown in the graph L. A driving force TE can be obtained. As the vehicle speed GS increases, the driving force TE obtained at the output of the prime mover 1 decreases, and when the vehicle speed GS changes from SL to H, the forward high speed clutch 71 starts to be engaged (see graphs L and H). The driving force TE obtained by the forward high-speed gear train 50H obtained at this time is set so as to correspond to the climbing force of 30% of the inclined surface, so that the forward high-speed gear train 50H travels to the 30% inclined surface. Can be set to possible vehicles.

  Further, with respect to the vehicle speed GS at the time of forward travel, the separation point SH → L of the forward high speed clutch 71 as a switching point from the high speed stage to the low speed stage is engaged, and the forward high speed clutch 72 is engaged as the switching point from the low speed stage to the high speed stage. Since the hysteresis appears by shifting the point SL → H to the low speed side, stable performance can be obtained in a state where the vehicle speed is a value near the switching boundary between the clutches 71 and 72. it can.

  Further, regarding the vehicle speed GS during forward travel, the two speed stage switching points (clutch switching points) SL → H and SH → L are set in a region slower than about 1/2 with respect to the maximum speed of the vehicle. The high-speed stage is used more frequently than the low-speed stage, that is, the low-speed stage is hardly switched during normal driving so as to obtain efficient driving performance.

  When the reverse clutch is engaged, that is, when the shifter 56 is set to the reverse position, the reverse gear train 50R is set so as to obtain a high driving force TE with respect to the reverse vehicle speed GS. Is substantially equal to the characteristic of the driving force TE by the forward low-speed gear train 50L set for (see graph R). That is, a speed range that is slower than the speed range obtained by the forward high-speed gear train during normal travel is ensured.

  Next, the forward high speed clutch in the embodiment of FIGS. 5 and 6 will be described. In these embodiments, the forward high-speed driven gear 51 is engaged and separated from the forward driven shaft 27 via the forward high-speed clutch 73 having a hydraulic clutch structure. The forward high-speed clutch 73 is housed in a clutch case 22h attached to the rear end surface of the rear case portion 22c so as to protrude rearward. The clutch case 22h has a bearing at the rear end of the forward driven shaft 27 via a bearing, and an oil hole communicating with an oil passage 27a formed in the forward driven shaft 27 is formed in the wall portion.

  5 and 6, the rear end of the forward driven shaft 27 is a closed end so as to be supported by the clutch case 22h, and is more than the rear end of the speed change driven shaft 26. The oil passage 27a is formed in the rear extending portion. That is, only the front half portion of the forward driven shaft 27 is cylindrical, and the rear end portion of the speed change driven shaft 26 is fitted therein so as to be relatively rotatable.

  The hydraulic forward high-speed clutch 73 is connected to the forward driven shaft 27 so as to be relatively rotatable, and is engaged with the forward driven gear 51 so as not to be relatively rotatable. A drum-like driven member 73b on the downstream side of the transmission, which is circularly fixed to the rearward extending portion of the shaft 27, and a piston 73c are provided. Between the driving member 73a and the driven member 73b, a plurality of friction plates engaging with the driving member 73a and a plurality of friction plates engaging with the driven member 73b are alternately arranged. The oil passage 27a communicates with an oil chamber in the drive member 73a, and the piston 73c is spring-biased in a direction to separate the friction plates from each other, and according to the hydraulic pressure supplied to the oil chamber, the spring Operates in a direction to press the friction plates against each other against the urging force. That is, the hydraulic clutch type forward high speed clutch 73 is separated when the oil is removed from the oil chamber, and is engaged when oil is supplied to the oil chamber.

  Oil to the forward high-speed clutch 73 is discharged by a hydraulic pump 80 having the transmission shaft 23 as a drive shaft, and the electromagnetic switching valve 81 at the supply position, the oil hole in the wall of the clutch case 22h, and the forward driven shaft 27. Then, the oil is supplied to the oil chamber through an oil passage 27a. The hydraulic pressure from the electromagnetic switching valve 81 to the oil passage 27 a is adjusted by the hydraulic pressure adjustment valve 83, and the discharged oil that has passed through the hydraulic pressure adjustment valve 83 is supplied as lubricating oil to the forward high speed clutch 73. . Further, a lubricating oil pressure adjusting valve 84 is provided to adjust the lubricating oil pressure.

  The electromagnetic switching valve 81 includes a supply position for supplying oil to the oil passage 27a and the oil chamber in the forward high speed clutch 73 by excitation / demagnetization of the solenoid, the hydraulic pump 80, and the oil chamber of the forward high speed clutch 73. It is switched to the discharge position for discharging more oil. As shown in FIG. 8, a rotational speed sensor 82 attached to the mission case 3 (rear case portion 22c) is electrically connected to a controller (not shown) that performs the solenoid switching control. In FIG. 8, the rotational speed sensor 82 detects the rotational speed of the speed change drive shaft 25, but an appropriate one of the rotational shafts supported in the mission case 3 is selected and the rotational speed is selected. May be detected.

  In the controller, the rotational speed sensor 82 has reduced the rotational speed of the rotational shaft (transmission drive shaft 25) to be detected to a rotational speed at which the forward low-speed clutch 72, which is the above-described overrunning clutch, starts to be engaged. When detected, the electromagnetic switching valve 81 is set to the discharge position so as to start separating the forward high speed clutch 73.

  Thus, in the state where the shifter 56 is disposed at the forward position, the electromagnetic switching valve 81 is set to the supply position during normal traveling, and the forward high speed clutch 73 is engaged by the oil supply from the hydraulic pump 80. The forward low-speed clutch 72, which is an overrunning clutch, is disengaged, and the forward high-speed gear train 50H of the forward high-speed gear train 50H and the forward low-speed gear train 50L is drivingly connected to the forward driven shaft 27 to advance the speed-change driven shaft 26. It rotates at high speed. When the speed of the speed change drive shaft 25 is less than a constant value, such as when starting or when a traveling load is applied, the electromagnetic switching valve 81 is switched to the discharge position, and the forward high speed clutch 73 is separated while the forward speed is increased. The low speed clutch 72 is engaged, the forward low speed gear train 50L is drivingly connected to the forward driven shaft 27, and the variable speed driven shaft 26 is rotated forward at low speed.

  The driving force TE characteristic with respect to the vehicle speed GS according to this embodiment is seen in the graph of FIG. 11 described above, and the graph L is obtained by engaging the forward low speed clutch 72 (and setting the shifter 56 to the forward position). Travel characteristics by the forward low speed gear train 50L, graph H shows travel characteristics by the forward high speed gear train 50H obtained by engaging the forward high speed clutch 73 (and shifting the shifter 56 to the forward position), and graph R shows engagement of the reverse clutch. The travel characteristics by the reverse gear train 50R obtained by (that is, the shifter 56 is set to the reverse position) are shown.

  Therefore, in each of the travel power transmission devices of FIGS. 5 and 6, when the vehicle speed GS reaches SL → H in the process of increasing the vehicle speed GS from the forward start, the electromagnetic switching valve 81 that has been in the supply position is changed to the discharge position. The forward high speed clutch 73 is engaged by switching, and when the vehicle speed GS reaches SH → L during deceleration, the electromagnetic switching valve 81 which has been in the discharge position is switched to the supply position, and the forward high speed clutch 73 is separated. What should I do.

  As described above, FIG. 5 shows that the centrifugal clutch 70 is provided on the transmission upstream side of the CVT 40, and FIG. 6 shows the implementation in which the centrifugal clutch 70 is provided on the transmission downstream side of the CVT 40 (between the CVT 40 and the gear type transmission 50). As an example.

  Next, the forward high speed clutch in the embodiment of FIG. 7 will be described. In FIGS. 3 to 6, the forward high speed clutch 71 or 73 is interposed between the forward high speed driven gear 51 and the forward driven shaft 27. In the embodiment of FIG. A clutch 71 is interposed between the speed change drive shaft 25 and the forward high speed drive gear 25a. That is, the drive member 71a having the weight 71b is fixed to the speed change drive shaft 25, and the drum-like driven member 71c is fixed to the forward high speed drive gear 25a, and the rotational speed of the speed change drive shaft 25 is reduced below a certain number. Sometimes, the forward high speed clutch 71 is separated and the forward high speed gear train 50H is separated from the transmission drive shaft 25.

  A hydraulic forward high speed clutch 73 may be interposed between the speed change drive shaft 25 and the forward high speed drive gear 25a. In FIG. 7, the centrifugal clutch 70 is provided between the transmission shaft 23 and the pulley shaft 41a (on the transmission upstream side of the CVT 40), but the forward high-speed clutch 71 or 73 is replaced with the transmission drive shaft 25 and the forward high-speed drive gear 25a. 4 or 6, the centrifugal clutch 70 is interposed between the pulley shaft 42a and the speed change drive shaft 25 (between the CVT 40 and the gear type transmission 50). May be.

  Next, the structure of the forward high speed clutch and the forward low speed clutch in each embodiment of FIGS. 9 and 10 will be described. The forward high-speed clutch for the forward high-speed gear train 50H and the forward low-speed clutch for the forward low-speed gear train 50L in each of the embodiments of FIGS. 9 and 10 both have the drive gears 25a and 25b with respect to the transmission drive shaft 25. In the embodiment of FIG. 9, both the forward high speed clutch and the forward low speed clutch are hydraulic clutches. In the embodiment of FIG. 10, the forward high speed clutch is a hydraulic clutch, and the forward low speed clutch is a dog clutch. .

  First, the hydraulic clutch mechanism 74 provided with the hydraulic forward low speed clutch 74L and the forward high speed clutch 74H in FIG. 9 will be described. The rear end of the speed change drive shaft 25 protrudes rearward from the rear end surface of the rear case portion 22c, and the rear protruding portion slides in a shaft case 22i attached to the rear end surface of the rear case portion 22c so as to protrude rearward. It is pivotally supported. In the transmission case 3 (in the rear case portion 22c), as described above, the forward high-speed drive gear 25a and the forward low-speed drive gear 25b are loosely arranged (via bearings) on the transmission drive shaft 25. A boss portion of a drive member 74a common to both clutches 74L and 74H in the hydraulic clutch mechanism 74 is fixed to the speed change drive shaft 25 between the gears 25a and 25b. The drive member 74a extends in the radial direction at the front-rear central portion of the boss portion, and has a drum-like portion extending in the front-rear direction from the outer peripheral end thereof.

  The front end portion of the forward high-speed drive gear 25a extends forward, and is inserted into a rear oil chamber formed between a drum-like portion and a boss portion extending rearward from the front-rear center portion of the drive member 74a. In the rear oil chamber, the friction plate 74d engaged with the rearward extension portion of the drum-like portion of the drive member 74a and the friction plate 74e engaged with the front extension portion of the forward high-speed drive gear 25a are alternately arranged. The forward high speed clutch 74H is arranged.

  On the other hand, the rear end portion of the forward low-speed drive gear 25b extends rearward and is inserted into the front oil chamber formed between the drum-like portion extending forward from the front-rear center portion of the drive member 74a and the boss portion. In the front oil chamber, the friction plate 74f engaged with the front extension portion of the drum-like portion of the drive member 74a and the friction plate 74g engaged with the rear extension portion of the forward low-speed drive gear 25b are alternately arranged. The forward low-speed clutch 74L is configured.

  In the rear oil chamber constituting the forward high speed clutch 74H, an axially slidable piston 74b is disposed between the friction plates 74d and 74e and the radially extending portion at the front and rear central portion of the drive member 74a. It is arranged. Further, a spring 74j that urges the piston 74b toward the anti-friction plates 74d and 74e, that is, the separation side (front) of the forward high speed clutch 74H is disposed in the rear oil chamber.

  In the hydraulic oil chamber on the front side of the piston 74b in the rear oil chamber, a hydraulic oil passage 25d drilled in the speed change drive shaft 25 passes through an oil hole drilled in a boss portion of the drive member 74a. With the supply of oil from the hydraulic oil passage 25d to the hydraulic oil chamber, the piston 74b is pushed toward the friction plates 74d and 74e (rear) against the spring 74j, and the friction plate 74d -Crimp 74e together and engage forward high speed clutch 74H.

  Further, an interlocking pin 74c extends forward from the piston 74b, passes through the drum-like portion of the drive member 74a so as to be slidable in the axial direction, and the friction plate 74f of the forward low-speed clutch 74L in the front oil chamber. It faces 74g. When the piston 74b urged by the spring 74j is in the initial position in a state where oil is removed from the hydraulic oil chamber in the rear oil chamber, the friction plates 74d and 74e are separated from each other, and the forward high-speed clutch 74H is separated, and at this time, since the interlocking pin 74c is at the front end position of the sliding region, the friction plates 74f and 74g are pressure-bonded and the forward low-speed clutch 74L is engaged.

  On the other hand, when the oil is supplied to the hydraulic oil chamber, as described above, the piston 74b slides backward to crimp the friction plates 74d and 74e and engage the forward high speed clutch 74H. 74c slides back along with the piston 74b, separates the friction plates 74f and 74g, and separates the forward low-speed clutch 74L.

  In this way, the hydraulic clutch mechanism 74 is interlocked so that the forward low-speed clutch 74L and the forward high-speed clutch 74H are engaged / separated against each other. In FIG. 9, for convenience, the state of the forward high speed clutch 74H being separated and the forward low speed clutch 74L is engaged is shown on the upper side of the speed change drive shaft 25, and the forward high speed clutch 74H is engaged. The state at the time of separation is illustrated below the speed change drive shaft 25.

  The aforementioned hydraulic oil passage 25d extends in the axial direction in the speed change drive shaft 25, and its rear end opens in the shaft case 22i, and is drilled through the wall of the shaft case 22i. The oil from the hydraulic pump 80 is received via the electromagnetic switching valve 81 through the oil hole as in the embodiment of FIGS. As described above, the electromagnetic switching valve 81 is switched between the supply position and the discharge position based on the detection value of the rotation speed sensor 82 that detects the rotation speed of the speed change drive shaft 25 and the like. When the electromagnetic switching valve 81 is set to the discharge position, the piston 74b is in the initial position, and the hydraulic clutch mechanism 74 disengages the forward high speed clutch 74H and engages the forward low speed clutch 74L to shift the forward low speed gear train 50L. Drive coupled to the shaft 25. When the electromagnetic switching valve 81 is set to the supply position, the hydraulic clutch mechanism 74 operates the piston 74b to engage the forward high speed clutch 74H, separate the forward low speed clutch 74L, and shift the forward high speed gear train 50H. Drive-coupled to the drive shaft 25. The switching timing of the electromagnetic switching valve 81 is set so that the running characteristics of FIG. 11 can be obtained as in the embodiment of FIGS.

  The transmission drive shaft 25 is provided with a lubricating oil passage 25e parallel to the hydraulic oil passage 25d. The rear end of the transmission drive shaft 25 opens in the shaft case 22i and is oil supplied from the hydraulic pump 80. 5 and 6 is supplied to the lubricating oil passage 25e as the friction plate lubricating oil of the forward high speed clutch 74H and the forward low speed clutch 74L. ing. The lubricating oil passage 25e is provided with a lubricating plate 74d and 74e on the rear side of the piston 74b in the rear oil chamber of the hydraulic clutch mechanism 74 through a through hole formed in the boss portion of the driving member 74a. It opens to the oil chamber and the lubricating oil chamber in which the friction plates 74f and 74g in the front oil chamber are disposed.

  Next, a structure in which the hydraulic forward high-speed clutch 75 and the forward low-speed clutch 76 having a dog clutch structure are interlocked and linked in FIG. 10 will be described. The shaft support structure of the speed change drive shaft 25 using the shaft case 22i and the loose fit structure of the forward high speed drive gear 25a and the forward low speed drive gear 25b on the speed change drive shaft 25 are the same as in the embodiment of FIG. A boss portion of the drive member 75a of the forward high speed clutch 75 is fixed to the speed change drive shaft 25 between both the gears 25a and 25b. The drive member 75a extends in the radial direction at the front end of the boss portion, and extends a drum-like portion behind the outer peripheral end.

  The front end portion of the forward high-speed drive gear 25a extends forward and is inserted into an oil chamber formed between the drum-like portion and the boss portion of the drive member 75a. In the oil chamber, the drive member 75a The forward high speed clutch 75 is configured by alternately arranging the friction plate 75c engaged with the drum-like portion and the friction plate 75d engaged with the forward extension portion of the forward high speed drive gear 25a.

  In the oil chamber of the forward high speed clutch 75, an axially slidable piston 75b is disposed between the friction plates 75c and 75d and the radially extending portion at the front end of the drive member 75a. . Furthermore, a spring 75e that urges the piston 75b toward the anti-friction plates 75c and 75d, that is, the separation side (front) of the forward high speed clutch 75 is disposed in the oil chamber.

  In the hydraulic oil chamber on the front side of the piston 75b in the oil chamber, a hydraulic oil passage 25d drilled in the speed change drive shaft 25 is opened through an oil hole drilled in a boss portion of the drive member 75a. By supplying oil from the hydraulic oil passage 25d to the hydraulic oil chamber, the piston 75b is pushed toward the friction plates 75c and 75d (rear) against the spring 75e, and the friction plates 75c and 75d The forward high speed clutch 75 is engaged by crimping them together.

  The friction plates 75c and 75d are urged in the pressing direction between the rearmost friction plate 75c of the forward high-speed drive clutch 75 and a stopper 75g fixed to the rear end of the drum-like portion of the drive member 75a. A disc spring 75h is interposed. When oil is removed from the hydraulic oil chamber in front of the piston 75b, the pawls 76b and 26f of the forward low speed clutch 76, which is a dog clutch, mesh with the piston 75b as described later. By engaging the friction plates 75c and 75d with a slight pressing force so that the pressure between the friction plates 75c and 75d in the forward high-speed clutch 75 is not completely lost when meshing, the claws 76b and 76f are pressed. The shock at the time of meshing is reduced.

  An interlocking pin 75f extends forward from the piston 75b, passes through the drum-like portion of the drive member 75a so as to be slidable in the axial direction, and protrudes forward from the front end of the drive member 75a. Further, the push arm 77 is pivotally supported by the outer peripheral portion of the front end of the drive member 75 a, and the front end portion of the interlocking pin 75 f is in contact with the push arm 77.

  Between the forward low-speed drive gear 25b and the drive member 75a, a clutch slider 76a is provided on the transmission drive shaft 25 so as to be slidable in the axial direction by spline fitting. The front portion of the clutch slider 76a has a cylindrical shape centering on the speed change drive shaft 25, and a claw 76b is formed at the front end thereof so that it can mesh with a claw 25f formed at the rear end portion of the forward low-speed drive gear 25b. I have to. That is, the clutch slider 76a and the forward low-speed drive gear 25b constitute a forward low-speed clutch 76 that is a dog clutch.

  In the cylindrical portion of the clutch slider 76a, a spring 76c for urging the clutch slider 76a toward the counter-forward / low-speed drive gear 25b (rear) is wound around the speed change drive shaft 25. The rear portion of the clutch slider 76a is a boss portion that is spline-fitted to the speed change drive shaft 25, and a vertical surface formed between the tubular portion and the boss portion on the boss portion. A disc spring 76d is provided between the pusher arm 77 and the above-described push arm 77. The disc spring 76d is a buffer member that relaxes the engagement of the clutch slider 76a with the forward low-speed drive gear 25b due to the operation of the push arm 77.

  When the piston 75b biased by the spring 75e is in the initial position in the state where the oil is removed from the hydraulic oil chamber in the forward oil clutch 75, the friction plates 75c and 75d are separated from each other. Since the forward high-speed clutch 75 is separated and the interlocking pin 75f is at the front end position of the sliding area at this time, the pushing arm 77 is rotated forward, against the spring 76c. The moving arm 77 pushes the clutch slider 76a forward via the disc spring 76d, and the claws 76b and 25f are engaged with each other, that is, the forward low-speed clutch 76 is engaged.

  On the other hand, when oil is supplied to the hydraulic oil chamber of the forward high-speed clutch 75, the piston 75b slides backward as described above, and the friction plates 75c and 75d are pressure-bonded, and the forward high-speed clutch 75 is engaged. At this time, the interlocking pin 75f slides back along with the piston 75b, and as a result, the clutch slider 76a slides backward by the urging force of the spring 76c, separating the claw 76b from the claw 25f, and the forward low speed clutch. 76 is spaced apart.

  As described above, in the embodiment of FIG. 10, the forward high speed clutch 75 and the forward low speed clutch 76 are interlocked so as to be engaged / separated against each other. In FIG. 10, for convenience, the state of the forward high speed clutch 75 being separated and the forward low speed clutch 76 is engaged is shown on the upper side of the transmission drive shaft 25, and the forward high speed clutch 75 is engaged. The state at the time of separation is illustrated below the speed change drive shaft 25.

  Oil from the hydraulic pump 80 is supplied to the hydraulic oil passage 25d via an electromagnetic switching valve 81 that is switch-controlled based on the detection value of the rotational speed sensor 82, and supplied to the forward high speed clutch 75 as hydraulic oil for the piston 75b. The structure and the structure for supplying the lubricating oil to the forward high speed clutch 75 via the lubricating oil passage 25e formed in the operating hydraulic pressure adjusting valve 83 and the transmission drive shaft 25 are the same as in the embodiment in FIG. In addition, the switching timing of the electromagnetic switching valve 81 is set so that the running characteristics shown in FIG. 11 can be obtained as in the embodiments of FIGS.

  As described above, in FIG. 9 and FIG. 10, the forward high speed clutch and the forward low speed clutch are linked and linked with respect to their contradicting engagement / separation operation by the mechanical link structure. 9 and 10, a centrifugal clutch 70 with an overclutch 70d as shown in FIG. 5 or 6 is preferably provided on the transmission upstream side of the gear-type transmission 50. Is.

  Next, as shown in FIGS. 3 to 7, a center differential gear mechanism 60 housed in the mission case 3 will be described with reference to FIG. 12 discloses the center differential gear mechanism 60b having a limited slip differential structure, but FIG. 12 is used to describe the structure common to the center differential gear mechanism 60 shown in FIGS. It is.

  As described above, the bull gear 61 that meshes with the final pinion 26a of the speed change driven shaft 26 is fixed to the differential case 72. The differential case 72 includes a front end of the rear output shaft 5 and a rear end of the front output shaft 6 from the front and rear ends. The ends are fitted so as to be rotatable relative to each other, and a differential side gear 65 is fixed to each end. A pinion shaft 63 is inserted and locked to the differential case 72 via a locking pin 63a. In the differential case 72, a differential pinion 64 is provided around the pinion shaft 63 so as to be relatively rotatable. 65 is engaged.

  Further, the center differential gear mechanism 60 is provided with a differential lock mechanism 60a. The differential lock mechanism 60 a is engaged with the shifter 67 slidably provided in the axial direction at the front and rear end portions (rear end portion in this embodiment) of the extended differential case 62, and engages with the shifter 67 from the outside of the transmission case 3. It comprises an operable fork 56 and a lock pin 58 fixed to the shifter 67. Further, one of the differential side gears 65 and 65 (in this embodiment, the rear differential side gear 65) has a recess 65a. A lock pin 68 that slidably penetrates the differential case 62 can be fitted into the recess 65a.

  When the shifter 57 is set to the differential lock position, the lock pin 68 is fitted into the recess 65 a, whereby the differential side gear 65 (the rear differential side gear 65 in this embodiment) is locked to the differential case 62. The differential side gear 65 locked to the differential case 62 is also locked to the differential case 62 via the differential pinion 64. In this way, the rear output shaft 5 and the front output shaft 6 are connected so as to be non-differentiable. On the other hand, when the shifter 57 is set to the differential lock release position, the lock pin 68 is disengaged from the recess 65a, and the differential side gear 65 can rotate relative to the differential case 62, so that the rear output shaft 6 and the front output shaft 5 can be differentially operated. It becomes.

  The above is the structure common to the center differential mechanism 60 shown in FIGS. 3 to 7, the limited slip type center differential mechanism 60b shown in FIG. 9, and the other limited slip type center differential mechanism 60c shown in FIG.

  Next, a structure unique to the limited slip type center differential mechanism 60b of FIG. 9 will be described. In the center differential mechanism 60b, a differential side gear 65 (front side in this embodiment) opposite to the differential side gear 65 (rear side in this embodiment) that can be engaged with the lock pin 68 of the differential lock mechanism 60a, a differential case 62, In the meantime, the disks that engage with the differential side gear 65 and the disks that engage with the differential case 62 are alternately arranged, and silicon oil is enclosed, and a viscous coupling 85 is interposed. A shearing resistance due to the viscosity of silicon oil is generated between the disks, and this resistance gives resistance to the relative rotation of the differential side gear 65 with respect to the differential case 62, whereby the rear output shaft 5 and the front output shaft 6 The differential is limited.

  Next, the unique structure of the limited slip type center differential mechanism 60c of FIG. 10 will be described. In this embodiment, both ends of the pinion shaft 63 are locked to the differential case 62 (via the locking pin 63a), and are point-symmetric with respect to the axis when viewed in the axial direction of the output shafts 5 and 6. A pair of differential pinions 64 and 64 are provided around the pinion shaft 63 so as to be relatively rotatable. A pressing member 86 is provided on the pinion shaft 63 between the differential pinions 64 and 64, and a disc spring 87 is interposed between the pinion shaft 63 and each differential side gear 65. In this way, the pinion shaft 63 imparts a resistance force in the thrust direction (axial direction) to the differential gears 65, thereby providing resistance to the relative rotation of the output shafts 5 and 6 with respect to the differential case 62. The differential with the front output shaft 6 is limited.

  The limited slip differential structure shown in FIGS. 9 and 10 may be applied to any of the center differential mechanisms 60 of FIGS. 3 to 7 and other embodiments not shown.

  The above is a recommended example of the present invention, and details such as the combination and arrangement of the members can be changed without departing from the scope of the claims.

It is a side view of a work vehicle (transport vehicle) to which the present invention is applied. It is a top view of this work vehicle. It is side surface sectional drawing of the traveling power transmission device which concerns on 1st Example of this invention. It is side surface sectional drawing of the traveling power transmission device which concerns on the 2nd Example of this invention. It is side surface sectional drawing of the traveling power transmission device which concerns on 3rd Example of this invention. It is side surface sectional drawing of the driving power transmission device which concerns on 4th Example of this invention. It is side surface sectional drawing of the traveling power transmission device which concerns on 5th Example of this invention. It is side surface sectional drawing of the forward low speed clutch 72 which is an overrunning clutch. It is a fragmentary side sectional view showing the components of the forward low speed clutch and the forward high speed clutch around the speed change drive shaft that is the main part of the traveling power transmission apparatus according to the sixth embodiment of the present invention. It is a fragmentary side sectional view showing the components of the forward low speed clutch and the forward high speed clutch around the speed change drive shaft, which is the main part of the traveling power transmission apparatus according to the seventh embodiment of the present invention. It is a graph which shows the change of the driving force with respect to the vehicle speed by the clutch control of the traveling power transmission device which concerns on this invention. It is a side sectional view of a limited slip type center differential mechanism. FIG. 6 is a side sectional view of another limited slip type center differential mechanism.

Explanation of symbols

1 Motor 2 CVT Case 3 Mission Case 4 Input Shaft 5 Rear Output Shaft 6 Front Output Shaft 22a Front Case (CVT Cover)
22b Middle case portion 22c Rear case portion 23 Transmission shaft 25 Drive transmission shaft 26 Transmission driven shaft 27 Advancement driven shaft 30 Adjustment gear train 40 CVT (belt type automatic continuously variable transmission (main transmission))
50 Gear type transmission (sub transmission)
50H forward high speed gear train 50L forward low speed gear train 50R reverse gear train 60 center differential mechanism 70 centrifugal clutch 71 (centrifugal) forward high speed clutch 72 (overrunning) forward low speed clutch 73 (hydraulic) forward high speed clutch 74 hydraulic clutch mechanism 74H (Hydraulic) Advance high speed clutch 74L (Hydraulic) Advance low speed clutch 75 (Hydraulic) Advance high speed clutch 76 (Dog clutch type) Advance low speed clutch

Claims (27)

  A traveling power transmission device for a vehicle having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle, the gear-type transmission including the belt-type automatic continuously variable transmission A first clutch that is engaged between an input unit that receives power from the machine and an output unit that outputs power to the axle when the rotational speed of the input unit is greater than or equal to a predetermined value. A gear train, and a second gear train having a reduction ratio different from that of the first gear train, the second gear train being engaged when the first clutch is not engaged. Traveling power transmission device.   The traveling power transmission device according to claim 1, wherein the first gear train is a high-speed gear train and the second gear train is a low-speed gear train.   The travel power transmission device according to claim 1 or 2, wherein the first clutch is a centrifugal clutch.   The travel power transmission device according to claim 1, wherein the first clutch is a hydraulic clutch.   The travel power transmission device according to any one of claims 1 to 4, wherein the second clutch is an overrunning clutch.   The travel power transmission device according to any one of claims 1 to 4, wherein the second clutch is a hydraulic clutch.   The travel power transmission device according to any one of claims 1 to 4, wherein the second clutch is a dog clutch.   2. A centrifugal clutch that is separated in an idle rotation speed range of the prime mover and engages when the transmission speed exceeds the idle rotation speed range is disposed upstream of the transmission of the gear type transmission. The travel power transmission device according to any one of claims 7 to 9.   9. An overrunning clutch that engages and bypasses the centrifugal clutch to transmit power when rotation on the drive side of the centrifugal clutch becomes lower than rotation on the driven side. A traveling power transmission device according to claim 1.   The travel power transmission device according to claim 8 or 9, wherein an adjustment gear train for adjusting an input rotational speed from the prime mover is disposed upstream of the transmission of the belt-type automatic continuously variable transmission.   The traveling power transmission device according to claim 10, wherein the centrifugal clutch is interposed between the adjustment gear train and the belt-type automatic continuously variable transmission.   The traveling power transmission device according to claim 10, wherein the centrifugal clutch is interposed between the belt-type automatic continuously variable transmission and the gear-type transmission.   The travel power transmission device according to any one of claims 1 to 12, wherein the belt-type automatic continuously variable transmission is disposed on the opposite side of the prime mover with the gear-type transmission interposed therebetween.   The switching point between the first gear train and the second gear train is set in a region slower than 1/2 with respect to the maximum speed of the vehicle. Travel power transmission device.   The gear-type transmission can selectively output rotation having a rotation direction different from that of the first gear train or the second gear train to the output unit without passing through the first and second clutches. The traveling power transmission device according to any one of claims 1 to 14, further comprising a third gear train and a third clutch interposed in the third gear train.   16. The traveling power transmission according to claim 15, wherein the third gear train is set to a speed reduction ratio that is larger than a speed reduction ratio of either the first gear train or the second gear train on a high speed side. apparatus.   14. The travel power transmission device according to claim 13, wherein the gear type transmission supports the belt type automatic continuously variable transmission and is mounted in a vibration-proof manner with respect to a vehicle frame.   The travel power transmission device according to claim 13 or 17, wherein the belt-type automatic continuously variable transmission is covered with a cover.   A traveling power transmission device having a belt-type automatic continuously variable transmission and a gear-type transmission interposed between a prime mover and an axle, wherein the idle speed of the prime mover is disposed upstream of the transmission of the gear-type transmission. A traveling power transmission device characterized in that a centrifugal clutch is provided which is separated in a region and engages when exceeding the idle rotation speed region.   20. An overrunning clutch is provided that engages and bypasses the centrifugal clutch to transmit power when the drive side rotation of the centrifugal clutch becomes lower than the driven side rotation. A traveling power transmission device according to claim 1.   The travel power transmission device according to claim 19, wherein a gear train for adjusting an input rotational speed from the prime mover is disposed on the transmission upstream side of the belt-type automatic continuously variable transmission.   The traveling power transmission device according to claim 19, wherein the centrifugal clutch is interposed between the gear train and the belt-type automatic continuously variable transmission.   The travel power transmission device according to claim 19, wherein the centrifugal clutch is interposed between the belt-type automatic continuously variable transmission and the gear-type transmission.   A traveling power transmission device comprising a belt-type automatic continuously variable transmission and a transmission mechanism driven by the belt-type automatic continuously variable transmission for transmitting power to a front axle and a rear axle arranged in front and rear of the vehicle The driving power transmission device is configured to input power to the belt-type automatic continuously variable transmission from a prime mover disposed between the front axle and the rear axle. The belt-type automatic continuously variable transmission is provided on the opposite side to the prime mover of the case that houses the transmission mechanism, and the prime mover passes through the front and rear surfaces of the case of the transmission mechanism. An output means for transmitting the output of the motor to the belt type automatic continuously variable transmission is supported.   The travel power transmission device according to claim 24, wherein the belt type automatic continuously variable transmission is covered with a cover.   The transmission mechanism in the traveling power transmission device includes a front output shaft that transmits power to the front axle and a rear output shaft that transmits power to the rear axle, and the front output shaft is connected to the front axle. 25. The transmission shaft connected to the axle or the transmission shaft connecting the rear output shaft to the rear axle is disposed on one side of the prime mover. Travel power transmission device. 25. The travel power transmission device according to claim 24, wherein an adjustment gear train for adjusting an input rotational speed from the prime mover is provided in the input means within the case of the transmission mechanism.

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