JP2006273228A - Travel transmission in working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a traveling transmission in a working vehicle capable of facilitating maintenance, and miniaturizing an entire configuration when interposing a HST in a transmission case. <P>SOLUTION: A rear plate 2 is provided on the rear end face of a transmission case 1 so as to be attachable and detachable, and constituted to receive the power of an engine E on a front side so as to close the rear end face, and a HST 3 stored in the transmission case 1 is mounted on the front side of the rear plate 2. A speed change gear 4 interlocked with an output shaft 57 of the HST 3 is provided on the front part of the transmission case 1, and a differential device 7 to interlock a rear axle 6 of an axle housing 5 is provided between the speed change gear 4 and the HST 3. In addition, a hydraulic pump P, an oil filter 8 or the like are mounted on the rear side of the rear plate 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a traveling transmission device for a work vehicle that simplifies the incorporation of an HST (hydraulic continuously variable transmission).

A technique for attaching the HST to the front side of the mission case (for example, see Patent Document 1) is known. That is, the transmission case is configured by connecting and integrating a gear case that surrounds the gear transmission portion and the HST case via an oil passage board, and a PTO clutch, a traveling gear reduction mechanism, and a differential device are accommodated in the transmission case. is doing. Engine power is configured to be input to the pump shaft of a hydraulic pump in the HST. A PTO clutch is interlocked and connected to a rear extension portion of the pump shaft, and a gear reduction mechanism is provided to a rear extension portion of the motor shaft of the hydraulic motor 1M. Linked together.
JP-A-8-283122 (second page, FIG. 2).

  In the transmission mode in which the engine is mounted on the front side of the tractor body and the transmission case is disposed on the rear side of the vehicle body, when the HST is interposed between the engine and the transmission case, the components of the HST are The configuration is such that it is almost hidden under the step floor or the like, which complicates the configuration and makes maintenance difficult.

  In the first aspect of the present invention, a rear plate 2 is detachably provided on the rear end surface of the transmission case 1 configured to receive engine E power on the front surface so as to close the rear end surface. It is set as the structure of the driving | running | working transmission apparatus in the working vehicle characterized by attaching HST3 accommodated in this mission case 1. FIG. Since the HST 3 is attached to the front side of the rear plate 2, the HST 3 can be mounted in the transmission case 1 by attaching the front side of the rear plate 2 to the rear end face of the transmission case 1.

  According to a second aspect of the present invention, in the first aspect of the present invention, the transmission gear 4 interlocked with the output shaft 57 of the HST 3 is provided in the front portion of the transmission case 1, and the axle housing is provided between the transmission gear 4 and the HST 3. 5 is provided with a differential device 7 that interlocks the rear axle 6 of the vehicle. The engine located on the front side of the transmission case 1 is linked to the HST 3 and is linked to the transmission gear 4 by the transmission transmission of the HST 3. The transmission transmission of the transmission gear 4 is linked to the rear axle 6 via the differential device 7.

  A third aspect of the invention is characterized in that, in the first or second aspect, a hydraulic pump P, an oil filter 8 or the like is attached to the rear side of the rear plate 2. As described above, the HST 3 is linked to the rear axle 6 through the transmission gear 4 and the rear differential device 7. The hydraulic pump P on the rear side of the rear plate 2 is driven from the input shaft or the like of the HST 3, and the oil in the transmission case 1 is filtered by the hydraulic pump P through the oil filter 8. To be replenished.

  In the first aspect of the invention, since the rear plate 2 with the HST 3 attached to the front side is attached and detached from the rear end face side of the transmission case 1, the rear side of the transmission case 1 has constituent members that obstruct this attachment / detachment operation. Because there are few, it is easy to attach and detach. In spite of the configuration in which the HST 3 is attached to the rear side, since it is housed in the mission case 1, it can be made shorter and compact in the front and rear length region of the mission case 1, and the wheel base can be made smaller and smaller. It is easy.

  According to the second aspect of the present invention, by providing the HST 3 in the rear end portion of the transmission case 1, the interlocking mechanism from the front engine can be provided close to the upper side of the lower differential device 7 as an interlocking shaft configuration. The upper height of the mission case 1 can be reduced.

  According to the third aspect of the present invention, since the hydraulic pump P for HST3, the oil filter 8 and the like are attached to the rear side surface of the rear plate 2 having the HST3, the configuration is simple and the attachment and detachment can be easily performed. Can do. Further, the hydraulic pump P can be driven at a high speed by directly driving the input shaft portion of the HST 3.

  An embodiment of the present invention will be described with reference to the drawings. First, based on FIG. 6, a vehicle body 11 includes four wheels having a front wheel 14 and a rear wheel 15 that can be steered by a steering handle 13 on a steering post 12. This is a driving mode. The front driver's seat 16 is covered with a cabin 17, and a collector 18 that houses the cut grass is mounted on the rear, and the grass that is cut by the mower 19 that is mounted on the front side of the vehicle body 11 is passed through the shooter 20. It can be conveyed and accommodated in the collector 18. On the front side of the vehicle body 11, there are provided a lift arm 22 that is pivoted up and down by the expansion and contraction of the lift cylinder 21, a lift link 23, and the like. In addition, a lift link 25 that is turned up and down by a lift arm 24 is provided at the rear end of the vehicle body 11 so that a working device can be connected and mounted.

  Further, the vehicle body 11 is mounted with an HST petal, a brake petal 30, a suspension, a shock absorber 31, a front axle housing 32, and the like at a front portion of a frame configured to have a predetermined height and width and long in the front-rear direction. The engine E, the transmission case 1, the rear axle housing 5 and the like are mounted on the rear part. The brake cylinder 33 that brakes the rear axle 6 and the master cylinder of the brake petal 30 are connected by a hydraulic hose 34. On the vehicle body 11 frame, a steering post 12, front and rear pillars 35 and 36 of the cabin 17, and a collector 18 are detachably provided. The steering post 12 houses a fully hydraulic steering device that is linked by a hydraulic circuit. The steering post 12, the cabin pillars 35 and 36, and the collector 18 are removed from the frame of the vehicle body 11, the front wheel 14 is removed from the front axle 38 of the front axle housing 32, and the rear wheel 6 is attached to the rear axle 6 of the rear axle housing 5. By removing 15, packing and storing in the container can be performed simply, and assembling, disassembling and the like can be easily performed (FIGS. 3 and 7).

  In the transmission case 1, gear shafts 41, 42, 43, a rear wheel take-out shaft 44, a front wheel take-out shaft 45, and the like are arranged in parallel, and their front end portions are pivotally supported on the front wall 46. An input case 47 is integrally formed on the upper portion of the front wall 46, and an engine body 49 is connected to the front end surface via a front plate 48. In the input case 47, the rear end portion of the crankshaft 50 of the engine E, the flywheel 51, and the like are supported, and the rear end is linked from the connected output shaft 52 to the gear shaft 41 via the speed increasing gear 53. The The rear end surface of the transmission case 1 is opened to the rear side, and the rear plate 2 is brought into contact with the open portion so as to be detachable. A rear differential device (rear wheel differential gear mechanism) 7, a rear axle 6 linked to the rear differential device 7, and the like are mounted below the transmission case 1. The rear axle housing 5 is connected to the left and right sides of the transmission case 1.

  On the front side surface of the rear plate 2, an HST base 55 with an HST case 54 integrated is attached. An HST input shaft 56 protruding from the HST pump side to the front side of the HST case 54 is detachably linked to the gear shaft 41 with a coupling 56a. Further, the HST output shaft 57 protruding from the HST motor side to the front side is detachably linked to the gear shaft 42 via the linkage shaft 58 with a coupling 57a.

  A trunnion shaft 59 is projected from the mission case 1 to the outer peripheral side on the side of the HST 3. A trunnion arm 60 is detachably fixed to the trunnion shaft 59, and the speed increase / decrease control can be performed by the expansion / contraction operation of the spindle 62 of the operation cylinder 61 connected to the trunnion arm 60. The trunnion arm 60 can be rotated from the transmission neutral position N to the forward high speed position F and the reverse high speed position R, and can perform a stepless main speed increase / decrease.

  A hydraulic pump P for HST is attached to the rear side surface of the rear plate 2 and is driven directly from the input shaft 56. An oil filter 8 is attached to the suction side of the hydraulic pump P, and the lubricating oil in the transmission case 1 can be suction filtered from the strainer 63 and replenished to the charge circuit of the HST 3.

  On the front side of the rear differential device 7, a rear wheel take-out shaft 44 having a transmission gear 4 as a sub-shift, a gear shaft 43 interlocked with the rear wheel take-out shaft 44, and a front wheel meshable with the gear shaft 43. A front wheel take-out shaft 45 having a take-out gear 64 is provided. The rear wheel take-out shaft 44 can be sub-shifted by selective engagement of the transmission gear 4 and is linked to the rear differential device 7.

  Since it is the above configuration, the trunnion arm 60 is removed from the trunnion shaft 59, the strainer 63 and the oil filter 8 are separated, and then the rear plate 2 is removed from the transmission case. The HST 3, the HST input shaft 56, and the HST output shaft 57 attached to the rear plate 2 through the HST base 55 are integrally removed. On the other hand, the hydraulic pump P and the oil filter 8 are removed from the rear plate 2 while being mounted. Therefore, after these are integrally removed from the mission case 1, individual parts and accessories can be inspected and replaced.

  When it is difficult to pull out the HST 3 immediately after the relationship between the trunnion shaft 59 and the trunnion arm 60, a detachable extension shaft is formed on the trunnion shaft 59, and the extension shaft is also removed when the HST 3 is removed. There is no hindrance to pulling backwards.

In addition, an oil passage from the hydraulic pump P can be formed in the HST base 55. If comprised in this way, piping can be abbreviate | omitted.
By engaging the front wheel take-out gear 64, the front wheel take-out shaft 45 can be interlocked to achieve a 4WD drive mode. An interlocking shaft 65 is connected to the front wheel take-out shaft 45, and a front differential (front wheel differential gear mechanism) 68 in the front axle housing 32 is interlocked via a universal joint 66 and an interlocking shaft 67.

  The front differential 68 has a central differential gear case 71 and an outer portion of the ring gear 72 on one side mounted on a center case 74 and a side metal 75 on the one side via a bearing 73. The side metal 75 can be closed and fixed with an O-ring or shim 76 interposed. A fixed brake surface 78 for receiving the wet friction brake disc 77 is formed on the outer surface of the center case 74 and the side metal 75, respectively. A differential shaft 79 projects from the differential gear portion of the differential gear case 71 outward in the left and right directions. The differential shaft 79 is supported by the side case 81 via a bearing 80. The left and right side cases 81 are formed substantially symmetrically and are attached to the outer surface of the center case 74 and the outer surface of the side metal 75. Inside these side cases 81, a spline boss 82, a brake disc 77, a pressure plate 83, and the like are incorporated. The spline boss 82 is movable in the axial direction with respect to the differential shaft 79 and can rotate integrally, and is configured to have a diameter as large as possible. A brake disk 77 is fitted between the spline portions formed on the outer periphery of the spline boss 82 and the inner periphery of the side case 81, and the pressure plate 82 is fitted to the spline portion on the inner peripheral portion of the side case 81. Each differential shaft 79 can be braked by pressing from the outer side to the inner brake surface 78. Further, the pressure plate 83 is formed in a dish shape with a curved central portion to enhance rigidity. A brake cam pin 84 in contact with the outer surface is supported by the side case 81, and the pin arm 85 at the outer end is connected to the wire 86 so that the brake operation can be performed by depressing the brake petal 30. The left and right differential shafts 79 are connected to the front axle 38 through universal joints or the like. An axle case 87 that supports the front axle 38 is supported via a suspension 88 and a shock absorber 31.

  The brake surface 78 that receives the brake disc 77 is formed in the center case 74 and the side metal 75 that closes one side thereof, so that the heat generated by the braking is effectively made by the lubricating oil in the front axle housing 32 itself. Can be cooled to. Further, by forming the brake surface 78 on the side metal 75 portion, the backlash can be easily adjusted. Further, the side case 81 can be simplified and simplified as a substantially right and left target shape. The brake capacity can be increased by increasing the diameter of the internal spline boss 82 and the diameter of the brake disc 77.

  The trunnion shaft 59 of the HST 3 detects the amount of rotation of the operation shaft by a potentiometer 96 by operating the HST lever 98 or an HST petal (traveling pedal) (not shown), and responds to the operation amount via the controller 97. The spindle 62 of the operation cylinder 61 can be expanded and contracted by driving the motor M, and the trunnion arm 60 and the trunnion shaft 59 are rotated to perform continuously variable transmission of the HST 3. The trunnion arm 60 is provided with a cam roller 91, and a neutral return cam 93 having a V-shaped cam edge 92 is ejected around a support shaft 95 by a spring 94. When the cam roller 91 is guided to the valley bottom of the V-shaped cam edge 92, the trunnion shaft 59 is in the neutral position N. Further, at the forward shift position F or the reverse shift position R, it is slidably guided to the inclined portion of the cam edge 92 and is configured to return to neutral by the spring 94 force.

  The operation cylinder 61 of the trunnion arm 60 operated against the neutral return cam 93 and the like has a guide pin 99, and the guide groove is formed in a reverse T shape on the bracket 100 fixed to the frame. 101 is fitted. The operating cylinder 61 has a check arm 102 and is tensioned upward by a spring 103. The guide pin 99 is guided in a state in which it can move back and forth along the bottom side 104 of the guide groove 101 and in a state in which it moves along the upper side 105 extending over the center. A tension spring 107 is provided between the guide pin 99 and the bracket 100. The spring 107 is set to have a weaker elasticity than the spring 103. For this reason, the guide pin 99 is normally engaged with the upper side portion 105 of the guide groove 101 by the force of the spring 103 and locked so as not to move in the front-rear direction, and the spindle 62 is locked to the cylinder 61 in this locked state. Is moved back and forth. The check arm 102 is connected to the stop lever 108 by a wire 109. When the stop lever 108 is operated to rotate the check arm 102 downward against the spring 103, the guide pin 99 moves freely along the bottom 104 of the guide groove 101 in the front-rear direction. The spindle 62 and the trunnion arm 60 are free to move back and forth together with the cylinder 61, and are returned to the neutral position N by the action of the neutral return cam 93. For this reason, the return to the neutral position of the cylinder 61, the spindle 62, etc. by the operation of the stop lever 108 is not performed properly in the electric circuit or the hydraulic circuit of the cylinder 61, for example, and the trunnion shaft 59 When the operation is locked in the middle position, the neutral return can be performed by the operation lever 108. Further, the operation lever 108 may be replaced by a stepping operation of the brake petal 30.

The side view of a mission case part. The side view (I) of the HST neutral return mechanism part, and a partial side view (B) which shows another example. The top view of a front differential part. The some enlarged plan view. The block diagram of the trunnion axis | shaft operation control part. A side view of a tractor. The side view which shows the decomposition | disassembly state of the flame | frame part.

Explanation of symbols

1 Mission case 2 Rear plate 3 HST
4 Transmission gear 5 Rear axle housing 6 Rear axle 7 Rear differential device 8 Oil filter

Claims (3)

A rear plate (2) is detachably provided at the rear end surface of the transmission case (1) configured to receive engine (E) power on the front surface so as to close the rear end surface. A traveling transmission device in a work vehicle, wherein an HST (3) to be accommodated in a mission case (1) is attached. A transmission gear (4) interlocking with the output shaft (57) of the HST (3) is provided at the front portion in the transmission case (1), and an axle housing is provided between the transmission gear (4) and the HST (3). The travel transmission device for a work vehicle according to claim 1, further comprising a differential device (7) for interlocking the axle (6) of (5). The travel transmission device for a work vehicle according to claim 1 or 2, wherein a hydraulic pump (P), an oil filter (8), and the like are attached to the rear side of the rear plate (2).

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