JP2000168383A - Transmission for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease a space occupied by a PTO shaft reverse rotation mechanism in a transmission case so as to reduce the number of part items and a cost of manufacture, by utilizing a main speed change gear as an idle gear for PTO shaft reverse rotation, in a transmission driving a running wheel and a PTO shaft of a work vehicle. SOLUTION: A PTO clutch slider 94 constituted relatively non-turnable to a PTO clutch shaft 29 is arranged in the forward of a PTO first-speed gear 61 and a gear 65 for reverse rotation, to be constituted slidably on the PTO clutch shaft 29. A pawl part for connecting to the PTO clutch slider 94 is provided in a tip end extended in a side of the PTO clutch shaft 29 of the PTO first-speed gear 61, and a front end of an extended part is constituted in the pawl part also in the gear 65 for reverse rotation. By connecting these pawl parts, drive force of a main shaft 25 is transmitted to the PTO clutch shaft 29 through a transmitting gear 41, main speed change first-speed gear 31, and the gear 65 for reverse rotation, to drive the PTO clutch shaft 29. A reverse rotation mechanism can be compactly constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a work vehicle, and more particularly to a technique for driving a PTO shaft.

[0002]

2. Description of the Related Art Hitherto, there has been known a transmission which is disposed in a work vehicle and drives a traveling wheel of the work vehicle and drives a PTO shaft. FIG. 9 is a side sectional development view showing a conventional PTO shaft reversing mechanism, and FIG. 10 is a front view showing an arrangement of conventional gears. The configuration of a conventional transmission will be described with reference to FIGS. The driving force from the engine is the main shaft 2
5, the transmission gear 4 integrally formed with the main shaft 25.
The driving force is transmitted to the main speed first gear 31 fitted on the traveling clutch shaft 24 and the idle gear 102 fitted on the pivot 101 via 1. The transmission gear 41 meshes with a PTO first speed gear 111 which is rotatably inserted into a PTO clutch shaft 29 which is a front end of the PTO shaft 15,
The idle gear 102 meshes with a PTO reverse rotation gear 112 that is rotatably fitted on the PTO clutch shaft 29.

In addition, the PTO first speed gear 111 and the PT
The O reverse rotation gear 112 is provided with a claw portion. The P
The PTO clutch shaft 29 is located near the TO first speed gear 111.
Is provided with a clutch slider 104 which is configured to be non-rotatable and slidable.
In the vicinity of 2, a clutch slider 105 that is configured to be non-rotatable and slidable relative to the PTO clutch shaft 29 is provided. By connecting the clutch slider 104 to the PTO first speed gear 111, the PTO clutch shaft 29 is driven together with the PTO first speed gear 111. Further, by connecting the clutch slider 105 to the PTO reverse rotation gear 112, the PTO clutch shaft 29 is driven together with the PTO reverse rotation gear 112. That is, the PTO shaft 15 can be driven in reverse rotation by driving the drive force of the transmission gear 41 to drive the PTO reverse rotation gear 112 via the idle gear 102.

[0004]

In the above prior art, in order to reversely rotate the PTO shaft, it is necessary to provide an idle gear and a pivot for pivotally supporting the idle gear, and the space occupied by the PTO reverse rotation mechanism is required. Becomes larger. For this reason, the mission case becomes large, and the degree of freedom in design decreases.

Further, since the idle gear receives a tooth surface load more than one, the tooth surface load is combined and the load applied to the idle gear, the pivot of the idle gear, and the bearing of the pivot increases.

[0006] It is necessary to provide a clutch slider for each of the PTO shaft forward rotation and the reverse rotation, and the space occupied in the transmission case of the PTO shaft reverse rotation mechanism becomes large, the transmission case becomes large, and the degree of freedom in design decreases. I do.

[0007]

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described. As described in claim 1, in the transmission for a work vehicle that drives the traveling wheels of the work vehicle and the PTO shaft, the main transmission gear is used as an idle gear for reverse rotation of the PTO shaft.

According to a second aspect of the present invention, a driving shaft of a main transmission gear is disposed on a side of a main shaft for driving a traveling wheel and a PTO shaft of a work vehicle and transmitting a driving force to the PTO shaft. In a transmission for a work vehicle in which a PTO shaft is disposed below a main shaft, a reverse rotation gear inserted into the PTO shaft has a large diameter and is meshed with the main transmission gear.

According to a third aspect of the present invention, a driving shaft of a main transmission gear is disposed on a side of a main shaft for driving a traveling wheel and a PTO shaft of a work vehicle and transmitting a driving force to the PTO shaft. In a transmission of a work vehicle in which a PTO shaft is disposed below a main shaft, a reverse rotation gear inserted into the PTO shaft is configured to have a large diameter, and is meshed with the main transmission gear, a forward rotation is performed by one clutch slider. And switching of reverse rotation.

[0010]

Next, embodiments of the present invention will be described. 1 is a side view of the work vehicle, FIG. 2 is a plan view of the work vehicle, FIG. 3 is a side cross-sectional developed view showing the structure of a main clutch and a transmission, and FIG. 4 is a skeleton diagram showing a power transmission structure of the work vehicle. 5 is a hydraulic circuit diagram of the work vehicle, FIG. 6 is a side sectional development view showing a mechanism for reversing the PTO shaft, FIG. 7 is a front view showing the arrangement of gears, and FIG. It is.

An overall configuration of a work vehicle according to one embodiment of the present invention will be described with reference to FIGS. In this work vehicle, a bonnet 6 is disposed at a front portion of a main body that suspends a front wheel 1 and a rear wheel 2 in front and rear, and an engine 5 is disposed inside the hood 6. A steering handle 10 is provided behind the hood 6, and a seat 11 is provided behind the steering handle 10. A main transmission lever 77 is provided on the side of the seat 11 to protrude. The steering handle 10 and the seat 11 are covered by a cabin 12.

A transmission case 9 is provided behind the engine 5.
And the motive power from the engine 5 is transmitted to the rear wheels 2 for driving. However, depending on the operation, a four-wheel drive that transmits the driving force to the front wheels 1 at the same time is also possible.

Further, the driving force of the engine 5 is transmitted to a PTO shaft 15 projecting from the rear end of the transmission case 9 and
The TO shaft 15 is driven to drive a working machine connected to the rear end of the machine.

At the feet of the operator who operates the work vehicle, a clutch pedal 16 as clutch operating means for connecting and disconnecting the clutch is supported. However,
A clutch lever may be used instead of the clutch pedal 16.

A work machine 100 is connected to the rear of the work vehicle, and a driving force is transmitted from the PTO shaft to the work machine, and the work machine 100 is driven. The working machine 100
Is configured such that the vertical position and the left and right inclination angles of the work implement 100 can be adjusted by an elevating device provided in the work vehicle.

Next, the configuration inside the transmission case 9 will be described with reference to FIGS. 3 and 4. FIG. Engine 5
A transmission case 9 is disposed at the rear of the vehicle, and the transmission case 9 is divided into two parts (9a and 9).
b), and the center plate 13 is sandwiched therebetween. Also, the transmission housing 9 in the rear half
Rear axle cases are fixed to the rear left and right sides of b.

Next, the configuration of the rear axle transmission system will be described. That is, a wet multi-plate type main clutch 21 linked to the clutch pedal 16 is disposed in the clutch cover 8, and the engine 5 is mounted on a driving side shaft 22 of the main clutch 21.
The rotation of the crankshaft is input. The driven side shaft 23 of the main clutch 21 extends rearward of the fuselage, and a main transmission fourth speed gear 34 loosely fitted to the traveling clutch shaft 24 meshes with a gear 23a formed at the rear end. The main transmission fourth speed gear 34 meshes with a transmission gear 44 fixed to the main shaft 25. Three transmission gears 41, 42 and 43 are further fixed or formed on the main shaft 25, and the three transmission gears 4
The main transmission first speed gear 31 and the main transmission second speed gear 3 each loosely fitted to the traveling clutch shaft 24 via the first, second and fourth gears 43
2. Power is transmitted to the main transmission third speed gear 33.

Therefore, when the driven side shaft 23 of the main clutch 21 rotates, the main speed first speed gear 31 and the main speed second speed gear 3
2. The main transmission third speed gear 33 and the main transmission fourth speed gear 34 rotate at different rotational speeds. Then, any one of the four hydraulic clutches 51, 52, 53, 54 is selected and brought into "contact" by the hydraulic control valve interlocked with the main shift lever 77, thereby enabling four-step shifting. , The rotation of the main shaft 25 goes through the speed change and the travel clutch shaft 24
Is transmitted to

The traveling clutch shaft 24 is mounted on the center plate 1
3 and extend rearward. A forward rotation side gear 26 and a reverse rotation side gear 27 are loosely fitted on the same axis on the extended portions. By operating a hydraulic control valve linked to a reversing lever 82 described later, the forward reversing hydraulic clutch 56 or the reversing reversing hydraulic clutch 57 is operated.
Is selected and connected, and the rotation of the traveling clutch shaft 24 is transmitted to either the forward rotation gear 26 or the reverse rotation gear 27. However, when the reversing lever 82 is in the neutral position, the rotation is not transmitted to both the gears 26 and 27.

The forward rotation gear 26 is non-rotatably connected to the auxiliary transmission shaft 35, and at the same time, meshes with a transmission gear 37 fixed to the creep transmission shaft 36.
・ Communicate to 36. The reverse rotation gear 27 meshes with a gear 39 formed at one end of a forward / reverse rotation shaft 38, and a gear 40 formed at the other end of the forward / reverse rotation shaft is fixed to a creep speed change shaft 36. The transmission gear 37 meshes. Accordingly, the rotation of the reverse rotation gear 27 causes the creep speed change shaft 36 to rotate in the reverse rotation direction via the forward / reverse rotation shaft 38. Further, the auxiliary transmission shaft 35 connected thereto is rotated in the reverse direction via the forward rotation gear 26 meshing with the transmission gear 37 of the creep transmission shaft 36.

A sub-transmission second shaft 45 is provided at the rear of the sub-transmission shaft 35.
Are arranged on the same axis so as to be freely rotatable, and a creep speed change gear 46 is loosely fitted to the auxiliary speed change second shaft 45. The creep speed change gear 46 meshes with a gear 47 formed on the creep speed change shaft 36. An input clutch slider 91 is spline-fitted to the auxiliary transmission second shaft 45 so as to be slidable in the axial direction, and is linked to a creep transmission lever (not shown). Therefore, the input clutch slider 91 can be engaged with either the auxiliary transmission shaft 35 or the creep transmission gear 46 by operating the creep transmission lever to transmit the rotation to the auxiliary transmission second shaft 45. That is, according to the selection based on the sliding of the input clutch slider 91, the rotation of the sub-transmission shaft 35 or the creep transmission shaft 36
Is input to the sub-transmission second shaft 45.

An output shaft 48 is supported in parallel with the auxiliary transmission second shaft 45. The output shaft 48 has two transmission gears 49
50 is fixed. The transmission gears 49 and 50 mesh with two transmission gears 59 and 60 loosely fitted on the auxiliary transmission second shaft 45. An output clutch slider 92 is spline-fitted to the sub-transmission second shaft 45 so as to be slidable in the axial direction. The output clutch slider 92 is linked to an unillustrated auxiliary shift lever. Therefore, the output clutch slider 92 is slid by the operation of the auxiliary transmission lever, and meshes with one of the two transmission gears 59 and 60, so that the auxiliary transmission second shaft 4 is engaged.
5 can be transmitted to one of the two transmission gears 59 and 60. Therefore, by the selection based on the sliding of the output clutch slider 92, the rotation of the sub-transmission second shaft 45 is output through the two-stage shift and input to the output shaft 48.

A rear wheel differential portion 66b is disposed at the rear portion 9b of the transmission housing, and the rotation of the output shaft 48 is input to the rear wheel differential portion 66b via the bevel gear 20 formed at the rear end, and the rear axle case is provided. The rear wheel 2 is driven via an internal axle, a transmission gear, and the like.

Next, the PTO transmission system will be described. That is, a PTO clutch shaft 29 is arranged in the transmission housing front portion 9a in parallel with the main shaft 25,
The O clutch shaft 29 has four PTO transmission gears, ie, PT
The first O gear 61, the second PTO gear 62, the third PTO gear 63, and the fourth PTO gear 64 are loosely fitted. The PTO transmission gears 61, 62, 63, and 64 are four transmission gears 41, 42, 43, 44 fixed or formed on the main shaft 25.
, And the rotation of the main shaft 25 causes the PTO transmission gears 61, 62, 63, and 64 to rotate at different rotational speeds. A PTO reverse rotation gear 65 is loosely fitted to the PTO clutch shaft 29, and the PTO reverse rotation gear 65 is loosely fitted to the traveling clutch shaft 24.
Is engaged. That is, the main speed first speed gear 31
The O-reversing mechanism also serves as an idle gear.

Further, two PTOs are provided on the PTO clutch shaft.
Clutch sliders 93 and 94 are spline-fitted slidably in the axial direction. Also, the PTO clutch slider 93
94 is linked to a PTO shift lever (not shown).
Therefore, by the selection based on the sliding of the two PTO clutch sliders 93 and 94, the rotation of the main shaft is transmitted to the PTO shaft after passing through the four-stage shift. Also, the main transmission first speed gear 31,
The rotation of the main shaft 25 is forward / reverse-converted and transmitted to the PTO clutch shaft 29 via the PTO reverse rotation gear 65. In other words, the fourth forward speed and the first reverse speed are shifted between the two shafts 25 and 29. The PTO clutch shaft 29 is connected to the PTO shaft 15 so as not to rotate relatively. The PTO shaft 15 extends rearward and drives a work implement 100 connected to the rear end of the work vehicle.

Next, the front axle transmission system will be described. That is, a pipe-shaped front wheel input shaft 55 is rotatably fitted to the PTO shaft 15, and the front wheel clutch shaft 30 is supported in parallel with the front wheel input shaft 55. An input gear 67 is fixed to the front wheel input shaft 55, and the input gear 67 is connected to the output shaft 4.
8 is engaged with one of the two transmission gears 49 fixed to the transmission gear 8. The front wheel input shaft 55 further includes two transmission gears 1.
8 and 19 are fixedly mounted, and the transmission gear is a front wheel clutch shaft 30.
The two gears, ie, the four-wheel drive-side gear 68 and the front-wheel double-speed gear 69, which are loosely fitted to the gears, respectively mesh with each other.

Then, by operating a hydraulic control valve interlocked with an unillustrated 4WD / front wheel double speed changeover switch, one of the two hydraulic clutches 78 and 79 is selected and connected, and the rotation of the front wheel input shaft 55 is substantially reduced. The power is transmitted to the front wheel clutch shaft 30 at double speed or substantially constant speed. The rotation of the front wheel clutch shaft 30 is input to the front wheel side differential portion 66a via the front wheel transmission shaft 14 connected to the front end, a universal joint, and the like.
The front wheels 1 are driven via an axle, a transmission gear and the like in the front axle case.

The configuration of the hydraulic circuit provided in the work vehicle having the above configuration will be described with reference to FIG. That is, the hydraulic oil in the oil tank (mission case) 71 is branched in two directions via a suction strainer 73, and one of the oil is pumped to a power steering unit 74 by a traveling hydraulic pump 72. The power steering unit 74 is provided to reduce the torque required to operate the steering handle 10,
The double-acting cylinder 76 connected to the front wheel steering device is driven by the switching valve 75 that is linked to 0, and gives a steering angle to the front wheels 1.

The hydraulic oil that has passed through the power steering unit 74 is branched into three, and one of the four hydraulic clutches 51, 52, 53, and 54 is operated by a main transmission control valve 80 linked to a main transmission lever 77. One of the gears is operated to perform the main shift. The other is through a proportional pressure reducing valve 81 and a reverser control valve 83 interlocked with a reverser lever 82 to control two hydraulic clutches 5 for reverser.
By operating any one of 6.57, the work vehicle is switched between forward and reverse. The proportional pressure reducing valve 81 is constituted by a switching valve formed of an electromagnetic valve. The rest passes through the electromagnetic control valve 95 and the two hydraulic clutches 78
79 is operated to switch between front wheel acceleration or four-wheel drive. At the time of increasing the speed of the front wheels, the braking devices 84 and 85 provided on the left and right sides of the rear wheels are operated to make the turning radius smaller by operating the inner one.

Next, the hydraulic circuit of the work machine control system will be described. From the oil tank 71 to the suction strainer 7
The hydraulic oil branched through 3 is a working machine hydraulic pump 86
As a result, it is pressure-fed to the working machine control unit 88 via the external hydraulic pressure take-out part 87. And the working machine lifting cylinder 8
9 and the work machine horizontal control cylinder 90 are appropriately operated to perform elevation and level control of the work machine connected to the rear end of the work vehicle.

In the above configuration, a part of the hydraulic oil pumped to the work machine control unit 88 by the work starting hydraulic pump 86 is supplied to the flow divider 88 of the work machine control unit 88.
is supplied to the main clutch 21 via a. Further, a drain oil for operating / cooling a power shift mechanism (main transmission mechanism) constituted by the hydraulic clutches 51, 52, 53, 54, 56, 57 is supplied to the main clutch 21 via the relief valve 101. It has become.

The working oil is supplied to the working machine control unit 88 by the working hydraulic pump 86, and the working machine is moved up and down and leveled by the working oil fed to the working machine control unit 88. The drain oil of the work machine control unit 88 and the working oil excessively pumped to the work machine control unit 88 are supplied to the main clutch 21 via the flow divider 88a. The hydraulic oil supplied to the main clutch 21 is used for cooling and lubricating the main clutch 21.

The hydraulic oil supplied to the power shift mechanism (main transmission mechanism) by the traveling system hydraulic pump 72 is used for operating or cooling the hydraulic clutches 51, 52, 53, 54, 56, 57. It is supplied to the relief valve 101 as drain oil. The operating oil via the relief valve 101 is supplied to the main clutch 21 and the main clutch 2
1 for cooling and lubrication.

The hydraulic oil introduced into the main clutch 21 from the work machine control unit 88 and the hydraulic oil introduced into the main clutch 21 via the power shift mechanism are merged into a junction 103.
And the main clutch 2
1 is supplied. Thereby, the main clutch 21 which is a wet clutch can be cooled by the drain circuit oil of the working oil for controlling the working machine and the hydraulic oil for shifting control. Therefore, the cooling oil for the main clutch 21 can be stably supplied without providing a special hydraulic pressure supply device.

The drain oil from the power shift mechanism is:
The supply of the drain oil from the power shift mechanism stops when the engine 5 is in an idling state, which varies depending on the rotation speed of the engine 5. For this reason, when the engine 5 is in the idling state, the main clutch 21 is not cooled by the drain oil from the power shift mechanism. However, since hydraulic oil is supplied to the main clutch 21 from the flow divider 88a of the work machine control unit 88, the main clutch 21
The minimum cooling oil amount can be secured. With the configuration described above, the operating oil for lubrication and cooling to the main clutch 21 can be stably supplied, and the durability of the main clutch 21 can be improved.
The speed change mechanism and the work implement control mechanism can be made compact.

Next, the configuration of the reverse rotation drive of the PTO shaft 15 will be described. 6 to 8, a driving force from the engine 5 drives a gear 23a integrally formed at the rear end of the driven-side shaft 23 via a clutch 21, and the gear 23a relatively rotates the steering clutch shaft 24. The main transmission fourth speed gear 34, which is inserted and fixed as possible, is driven. The main transmission fourth speed gear 34 meshes with a transmission gear 44 fixedly inserted and fixed to the main shaft 25 so as not to rotate relatively. When the transmission gear 44 is driven, the main shaft 25 is driven, and the transmission gear 41 which is integrally formed or fixed to the rear end of the main shaft 25 so as not to rotate relatively is driven.

The transmission gear 41 meshes with a main transmission first speed gear 31 which is rotatably inserted into the steering clutch shaft 24, and transmits a driving force to the main transmission first speed gear 31. The main transmission first speed gear 31 meshes with a reverse rotation gear 65 fixedly inserted and fixed to the PTO first speed gear 61 so as to be relatively rotatable. The transmission gear 41 is meshed with a PTO first speed gear 61 which is rotatably fitted on the PTO clutch shaft 29.

A PTO clutch slider 94 is provided in front of the PTO first speed gear 61 and the reverse rotation gear 65 so as not to rotate relative to the PTO clutch shaft 29. It is configured to be slidable on the PTO clutch shaft 29. The PTO clutch shaft 29 side of the PTO first speed gear 61 extends forward on the PTO clutch shaft 29, and a claw portion for connecting to the PTO clutch slider 94 is provided at the extended tip. Have been. Similarly, in the reverse rotation gear 65, a part of the reverse rotation gear 65 is extended forward, and the front end of the extended portion is formed as a claw for connecting to the PTO clutch slider 94.

With the above configuration, by sliding the PTO clutch slider 94 and connecting the PTO clutch slider 94 to the reverse rotation gear 65 or the first PTO first speed gear 61, the reverse rotation gear 65 or the PTO first speed gear 61 is connected. The driving force can be transmitted from the speed gear 61 to the PTO clutch shaft 29. The driving force of the main shaft 25 is transmitted to the PTO clutch shaft 29 via the transmission gear 41 and the PTO first speed gear 61 by connecting the PTO clutch slider 94 and the claw portion of the PTO first speed gear 61, and the PTO clutch The shaft 29 is driven. That is, the driving force of the spindle 25 is P
The power is transmitted to the PTO clutch shaft 29 via the TO first speed gear 61.

By connecting the claw portion of the reverse rotation gear 65 with the PTO clutch slider 94, the driving force of the main shaft 25 is transmitted through the transmission gear 41, the main speed first speed gear 31 and the reverse rotation gear 65. 29 and the P
The TO clutch shaft 29 is driven. Assuming that the rotation direction of the PTO clutch shaft 29 by the PTO first speed gear 61 is forward rotation, the driving force of the main shaft 25 is transmitted to the reverse rotation gear 65 via the main transmission first speed gear 31, and the reverse rotation gear is transmitted. When the PTO clutch shaft 29 is driven by the transmission path to drive the PTO clutch shaft 29 together with the gear 65, the PTO clutch shaft 29 is driven.
The clutch shaft 29 is configured to rotate in the reverse direction. The front end of the PTO shaft 15 is connected to the rear end of the PTO clutch shaft 29, and the PT
The O-shaft 15 rotates.

Since the reverse rotation mechanism of the PTO shaft 15 is configured as described above, the reverse rotation mechanism of the PTO shaft 15 can be made compact, and the degree of freedom in design increases. The PTO shaft 1
The space for disposing the reverse rotation mechanism 5 can be reduced in the axial direction. This makes it possible to shorten the overall length of the mission. Further, an idle gear for forming a reverse rotation mechanism of the PTO shaft 15 and a shaft for pivotally supporting the idle gear are not required, and the number of parts is reduced.
Manufacturing costs are reduced, and assemblability and maintainability are improved.

In the above configuration, it is possible to switch between normal rotation and reverse rotation by one PTO clutch slider 94. The PTO clutch slider 94 is in a neutral position when not connected to any of the gear claws,
The driving force of any gear is not transmitted to the PTO clutch shaft 29. By sliding the PTO clutch slider 94 backward from the neutral position, it is possible to connect the PTO clutch slider 94 to the pawl of the PTO first speed gear 61. Further, by sliding the PTO clutch slider 94 backward from the connection position with the PTO first speed gear 61, the PTO clutch slider 94 and the claw portion of the reverse rotation gear 65 can be connected. Also, P
By sliding the TO clutch slider 94 forward from the neutral position, the PTO clutch slider 94
It is possible to connect to the claw portion of the O second speed gear 62.

That is, with the above structure, the one clutch slider 94 allows the PT
Switching between forward rotation and reverse rotation of the O clutch shaft 29 can be performed, the space occupied by the PTO shaft reverse rotation mechanism in the transmission case 9 can be reduced, the number of components is reduced, and the manufacturing cost is reduced. As well as improved assemblability.

Next, in FIG. 7, the main transmission first speed gear 31,
The arrangement of the main shaft 25 and the PTO clutch shaft 29 will be described. A main shaft 25 is disposed on the side of the main transmission first speed gear 31, and a transmission gear 41 that rotates together with the main shaft 25.
Are engaged. A PTO clutch shaft 29 is provided below the transmission gear 41.
A PTO first speed gear 61 is rotatably inserted into the first gear 61. PT below the main speed first gear 31
An O-clutch shaft 29 is provided, and a reverse rotation gear 65 inserted into the PTO clutch shaft 29 so as to be relatively rotatable meshes therewith. That is, the reverse rotation gear 65 is configured to directly mesh with the main transmission first speed gear 31, and is configured to be driven by the main transmission first speed gear 31.

As described above, since the main transmission first speed gear 31, the main shaft 25, and the PTO clutch shaft 29 are arranged, the reverse rotation mechanism of the PTO shaft 15 can be made compact, and the overall configuration of the transmission can be made compact. Also, the PTO shaft 15
When the gears are rotated in reverse, the tooth surface load received by the main transmission first speed gear 31 functioning as an idle gear is dispersed, and the load received by the main transmission first speed gear 31 and the main transmission first speed gear 31
Running clutch shaft 24 for inserting the
The load on the bearing portion can be reduced.

[0046]

The present invention is configured as described above.
The following effects are obtained. That is, in a transmission system for a work vehicle that drives a traveling wheel and a PTO shaft of the work vehicle, the main transmission gear is a PTO.
Since it is used as an idle gear for shaft reverse rotation, PTO
The shaft reverse rotation mechanism can be made compact, and the degree of freedom in design increases. The space for disposing the reverse rotation mechanism of the PTO shaft can be reduced in the axial direction. This makes it possible to shorten the overall length of the mission. Further, the need for an idle gear for forming a reverse rotation mechanism of the PTO shaft and a shaft for pivotally supporting the idle gear is eliminated, the number of parts is reduced, the manufacturing cost is reduced, and the assemblability and maintainability are improved. I do.

According to a second aspect of the present invention, a driving shaft of a main transmission gear is disposed on a side of a main shaft for driving a traveling wheel and a PTO shaft of a work vehicle and transmitting a driving force to the PTO shaft. In the transmission for a work vehicle in which the PTO shaft is disposed below the main shaft, the reverse rotation gear inserted into the PTO shaft is configured to have a large diameter and meshed with the main transmission gear. It can be made compact, and the overall configuration of the mission can be made compact. In the case where the PTO shaft is rotated in the reverse direction, the tooth surface load received by the main transmission first speed gear functioning as an idle gear is dispersed, and the load received by the main transmission first speed gear and the main transmission first speed gear are inserted. The load on the clutch shaft and the bearing portion of the traveling clutch shaft can be reduced.

According to a third aspect of the present invention, a driving shaft and a PTO shaft of a working vehicle are driven, and a pivot of a main transmission gear is disposed beside the main shaft for transmitting a driving force to the PTO shaft. In a transmission of a work vehicle in which a PTO shaft is disposed below a main shaft, a reverse rotation gear inserted into the PTO shaft is configured to have a large diameter, and is meshed with the main transmission gear, a forward rotation is performed by one clutch slider. Since the switching between the reverse rotation and the reverse rotation is performed, the space occupied by the PTO shaft reverse rotation mechanism in the transmission case can be reduced, the number of components can be reduced, the manufacturing cost can be reduced, and the assemblability can be improved.

[Brief description of the drawings]

FIG. 1 is a side view of a work vehicle.

FIG. 2 is a plan view of the same.

FIG. 3 is a side sectional developed view showing a configuration of a main clutch and a transmission.

FIG. 4 is a skeleton diagram showing a power transmission configuration of the work vehicle.

FIG. 5 is a hydraulic circuit diagram of the work vehicle.

FIG. 6 is a side sectional development view showing a mechanism for reversing the PTO shaft.

FIG. 7 is a front view showing an arrangement of gears.

FIG. 8 is a side sectional view showing a configuration of a reverse rotation gear.

FIG. 9 is a side sectional developed view showing a conventional PTO shaft reversing mechanism.

FIG. 10 is a front view showing a conventional gear arrangement.

[Explanation of symbols]

 Reference Signs List 5 engine 21 main clutch 24 traveling clutch shaft 25 main shaft 29 PTO clutch shaft 31 main transmission first speed gear 41 transmission gear 61 PTO first speed gear 65 reverse rotation gear 94 PTO clutch slider

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference)

Claims (3)

[Claims] In a transmission for a work vehicle that drives a traveling wheel of a work vehicle and a PTO shaft, a main transmission gear is a PTO.
A transmission for a work vehicle, wherein the transmission is used as an idle gear for reverse rotation of a shaft. 2. A driving system according to claim 1, further comprising: a drive shaft for driving a traveling wheel and a PTO shaft of the work vehicle; and a pivot for a main transmission gear disposed on a side of the main shaft for transmitting a driving force to the PTO shaft. In the transmission for a work vehicle, the reverse rotation gear inserted into the PTO shaft has a large diameter and meshes with the main transmission gear. 3. A drive shaft for driving a traveling wheel and a PTO shaft of a work vehicle, and a pivot of a main transmission gear disposed on a side of the main shaft for transmitting a driving force to the PTO shaft, wherein a PTO shaft is provided below the main shaft. In the transmission of a working vehicle in which the reverse rotation gear inserted into the PTO shaft is configured to have a large diameter and meshed with the main transmission gear, one clutch slider switches between normal rotation and reverse rotation. A transmission for a work vehicle, comprising: