JPH0117883B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a transmission that controls power transmission in a traveling work vehicle that performs ground work, reaping work, loading goods onto a transport vehicle, etc. be.

Prior Art A transmission, which controls only the transmission of running power, is housed in a vertical transmission case whose components are arranged compactly along the vertical direction and whose length in the longitudinal direction of the vehicle is relatively small. It is easy to understand. An example of this type of transmission is disclosed in US Pat. No. 4,103,566.

On the other hand, in a transmission that also controls the transmission of power for driving a working machine, it is difficult to arrange the components of the transmission in a compact manner as described above. For this reason, in conventional work vehicles such as agricultural tractors and riding field machines, transmission cases having a large length in the longitudinal direction of the vehicle have been used. Typical examples are shown in US Pat. No. 4,304,141 and No. 4,373,597.
In the tractors disclosed in these US patents, the transmission case is divided into two parts, a front case and a rear case, which are fixedly connected to each other. The front of the transmission case is equipped with a hydraulic transmission device that allows the vehicle to continuously change gears, including selectively moving the vehicle backwards. A gear type transmission device for changing the vehicle speed in steps and another gear type transmission device for changing the drive speed of the working machine in steps are disposed inside the front case. The former transmission is disposed in the rear half of the front case, and transmits power to the differential gear disposed in the rear case. The other gear-type transmission described above is located in the front half of the front case, and is connected to the rear PTO shaft that extends rearward from the rear case to drive the work equipment towed by the vehicle. Power is transmitted through the side case. The transmission disclosed in U.S. Patent No. 4304141 is further provided with a mid-PTO shaft for driving a mid-mount type working machine, and this mid-PTO shaft is connected to a separate case attached to the lower surface of the front case. It is extended to the front. The mid-PTO shaft is also powered by the gear-type PTO transmission located within the front half of the front case.

Problems to be Solved by the Invention The above-mentioned type of transmission has a transmission case having a large length in the longitudinal direction of the vehicle;
Therefore, a heavy transmission case is required. Such a transmission case makes assembly of the vehicle difficult and increases the weight of the vehicle.

It is therefore a principal object of the present invention to arrange the components in a compact manner that reduces the length and weight of the mission case in which they are housed, and to reduce the length and weight of the mission case in a vertically compact manner. This makes installation easier and contributes to reducing the overall weight of the vehicle.
The purpose of the present invention is to provide a new transmission for self-propelled work vehicles.

Technical Means for Solving the Problems In order to solve the problems of the present invention, the present invention has taken the following technical means in a self-propelled working vehicle as illustrated in the attached drawings.

That is, the first input shaft 22 that inputs running power into the transmission case 8 and the second input shaft 23 that inputs the working machine driving force are aligned in the front-rear direction, and the second input shaft 23 is aligned upward. The mission case 8
Inside, the second input shaft 23 and a rear shaft extending rearward from an intermediate level inside the transmission case 8
The PTO clutch mechanisms 31, 36 and the PTO transmission 32 are installed between the PTO shaft 17, with the PTO transmission 32 arranged on the rear side and staggered back and forth. A vehicle speed change device 43 and a differential device 44 are connected between the first input shaft 22 and the left and right rear wheel drive shafts 57 extending left and right from a low level inside the transmission case 8 on the lower side of the transmission case 32. 44 is placed on the rear side and installed so as to be staggered from front to back.

Then, a mid-PTO shaft 19 extending forward from a low level inside the transmission case 8 is disposed forward of the differential device 44 and to the side of the speed change shaft 25 of the vehicle speed change device 43. 8, and the PTO clutch mechanism 31, 3
6 includes a PTO switching clutch 36 capable of selectively switching and transmitting working machine driving force to the rear PTO shaft 17 and the mid PTO shaft 19, and the mid PTO shaft 19 is Mitsudou
Gear trains 72, 7 are provided inside the transmission case 8 on the side where the PTO shaft 19 is located.
4, 75 and the PTO clutch mechanism 31, 36, the input shaft 23 is interlocked with the second input shaft 23.

Function The transmission according to the present invention is a self-propelled working vehicle, in which the transmission case 8 is positioned between the left and right rear wheels 2 (FIGS. 1 and 2) that are driven by the left and right rear wheel drive shafts 57. It is used as

The rear PTO shaft 17 is used to drive working equipment such as a tiller or grass collector that is towed by the vehicle, and the mid-PTO shaft 19 is used to drive a mid-mounted type such as a mower that is mounted on the bottom of the vehicle in the center of the length direction of the vehicle. Used to drive work equipment.
The PTO switching clutch 36 is used to selectively switch and transmit the working machine driving force to the rear PTO shaft 17 and the mid PTO shaft 19.

Embodiment As shown in FIGS. 1 and 2, the illustrated embodiment is a relatively small tractor equipped with a mid-mounted mower M on the underside of the vehicle between a pair of left and right front wheels 1 and rear wheels 2. This relates to an example in which the present invention is implemented.

The engine 3 of the tractor is mounted on the front part of the machine, and a transmission mechanism receives input from the engine 3 through a power transmission shaft 6 equipped with flexible joints 4 and 5 at both ends. It is installed at the rear of the aircraft between the two. The transmission mechanism includes a hydraulic transmission device 7 located on the front side.
and a transmission in the transmission case 8 located on the rear side, transmitting input from the transmission shaft 6 to the hydraulic transmission device 7, and transmitting input from the hydraulic transmission device 7 into the transmission case 8. It is said that The passenger seat 9 is installed at the top of the rear part of the aircraft, and when operating a vehicle, use the passenger seat 9 as usual.
The operator sitting on the control handle 10 in front of the operator
This is done by turning the left and right front wheels 1.

The illustrated tractor is configured as a four-wheel drive type that drives the left and right rear wheels 2 and also drives the left and right front wheels 1 as necessary to allow the vehicle to travel. In order to drive the left and right rear wheels 2, the left and right rear wheel axles 12 are supported by the left and right axle housings 11 connected to the left and right sides of the transmission case 8, and the left and right rear wheels 2 are directly driven from inside the transmission case 8. A structure is adopted in which running power is transmitted to the wheel axle 12. In order to selectively drive the left and right front wheels 1, driving power is transmitted from a lower position inside the transmission case 8 to inside the front axle case 13.
A transmission shaft 16 is provided with flexible joints 14 and 15 at both ends, and a front wheel drive clutch is provided within the transmission case 8 at the base end of the transmission shaft 16. The PTO shafts include a rear PTO shaft 17 that extends rearward from inside the mission case 8 and can drive a working machine towed by the machine body, and a rear PTO shaft 17 that extends forward from a lower position inside the mission case 8 and has two shafts at both ends. A mid-PTO shaft 19 is provided which can transmit mower driving force into the driving gearbox Ma of the mower M via a transmission shaft 18 provided with a flexible joint.

As shown in FIG. 3, the hydraulic transmission device 7 includes a variable displacement hydraulic pump 20 and a constant displacement hydraulic motor 2.
1 and 1 are arranged vertically in parallel along the front-rear direction, but the input of running power into the transmission case 8 is from a hydraulic motor 21.
In addition, the working machine driving force is input from the hydraulic pump 20.
Hydraulic motor 2
One motor shaft is a first input shaft 22, and the pump shaft of the hydraulic pump 20 is a second input shaft 23, which are respectively inserted into the mission case 8. Therefore, the first input shaft 22 and the second input shaft 23 are placed in a vertically staggered manner with the second input shaft 23 on the upper side.

As shown in FIGS. 3 and 4, the transmission case 8 includes an intermediate shaft 24 and a speed change shaft 25 for the traveling system.
A PTO system transmission shaft 26, a clutch shaft 27, and an intermediate shaft 28 are provided along the front-rear direction, respectively. Of these, the PTO system shafts 26, 27, and 28 are formed with a length that occupies almost the entire front and rear width of the mission case 8, while the travel system shafts 24 and 25 are formed in the transmission case 8. It is installed in the front part of the inner part and has a length that is located only in the front part. The rear PTO shaft 17 is
It is installed so as to straddle the inside and outside of the mission case 8 with its front end located approximately at the rear end position of the shafts 24 and 25 of the traveling system. Further, the mid-PTO shaft 19 is installed to straddle the inside and outside of the transmission case 8, with approximately the same length as the shafts 24 and 25 of the traveling system, and approximately the same longitudinal position. In addition, the transmission case 8 is provided at the front end of the case 8 and is provided with the transmission shaft 1.
6 (Figs. 1 and 2), and a very short front wheel drive force extraction shaft 29 provided in the front end of the transmission case 8 as shown in Fig. 6. PTO system idler shaft 30 and
Each is equipped along the front and rear directions. The arrangement relationship of the axes described above in the vertical and horizontal directions is as shown in FIG.

The second input shaft 2 is located inside the transmission case 8.
3 and the rear PTO shaft 17 as shown in Fig. 3.
A clutch 31 and a PTO transmission 32 are provided. Among these, the PTO clutch 31 has a gear 34 meshed with a gear 33 fixedly installed on a transmission shaft 26 fixedly connected to the second input shaft 23, and a gear 34 loosely fitted on the clutch shaft 27. One and the other friction elements are slidably supported by a clutch housing 35 fixed on the clutch shaft 27, thereby forming a multi-plate hydraulic clutch. This PTO clutch 3
The intermediate shaft 28 receives transmission from the clutch shaft 27 via the PTO switching clutch 36, as will be described later. The PTO transmission 32 described above is configured to connect the intermediate shaft 28 and the rear PTO shaft 17 with a two-speed gear ratio. . That is, the transmission 32 includes two gears 37 and 38 fixedly installed on the intermediate shaft 28 and a rear PTO shaft 17.
The spline collar 4 is fitted with two gears 39 and 40 that are loosely fitted on the top to form a two-speed gear train, and is spline-fitted to the rear PTO shaft 17.
1 and between both gears 39 and 40, each of these gears 3
9 and 40 are provided with a shift metal fitting 42 for alternatively connecting them to the rear PTO shaft 17. And especially PTO clutch 31
clutch housing 35 and PTO transmission 32
The gear 37 on the front side on the intermediate shaft 28 in
The clutch housing 35 is placed on the front side and is staggered in the front and back, so that the PTO clutch 31 to which the PTO switching clutch 36 is attached
and the PTO transmission device 32 are installed so that the PTO transmission device 32 is disposed on the rear side and is staggered from the front to the rear.

And these PTO clutch mechanisms 31, 36
A vehicle speed change device 43 shown in FIG. 3 and a differential device 44 shown in FIG. 5 are installed in the transmission case 8 below the PTO transmission device 32.

As shown in FIG. 3, the vehicle speed change device 43 located below the PTO clutch mechanisms 31 and 36 is connected to the intermediate shaft 24 which receives transmission from the first input shaft 22 through the meshing of gears 45 and 46. The transmission shaft 25 has a small diameter bevel gear 48 meshed with a large diameter input bevel gear 47 of the moving device 44 at its rear end.
It is configured to be connected even with a two-speed gear ratio. That is, in addition to the gear 46, another gear 49 is fixedly installed on the intermediate shaft 24, and on the transmission shaft 25, a gear 49 is meshed with the two gears 46 and 49 on the intermediate shaft 24. Two gears 50 and 51 are loosely fitted, and a shift metal fitting 53 is installed between the two gears 50 and 51 so as to be able to slide freely through a spline tube 52. 50 and 51 are alternatively connected to the speed change shaft 25, so that the speed change shaft 25 can be rotated at variable speeds at two high and low speeds.

On the other hand, as shown in FIG. 5, the differential device 44 located below the PTO transmission 32 is connected to the input bevel gear in a differential case 54 rotatably supported by the transmission case 8. 47, and a pair of mutually meshed drive bevel gears 55 and 56 are installed inside the differential case 54. In the illustrated case, the left and right output shafts of the differential device 44 are configured as left and right rear wheel drive shafts 57 extending left and right from inside the transmission case 8, and the left and right axles 12 described above are configured as drive shafts 57 that extend left and right from inside the transmission case 8. It is disposed on an extension of the shaft 57 and supported by the left and right axle housings 11. Inside each axle housing 11, each rear wheel drive shaft 57
Disc brake 58 for selectively braking
A planetary gear reduction device 59 that connects each rear wheel drive shaft 57 and each axle 12 in a decelerating manner is provided.

As shown in FIG. 3, a support frame plate 60 is installed on the front of the mission case 8.
has the shape shown in FIG. 7 when viewed from the front;
It is fixed to the mission case 8 by a threaded bolt (not shown) that is screwed into a screw hole 62 shown in FIG. 4 through a bolt insertion hole 61 shown in the figure and into a screw hole 62 shown in FIG. As shown in FIG. 7, a screw hole 63 for fixing the hydraulic transmission device 7 is formed in the upper half of the support frame plate 60. As can be clearly understood from FIGS. 4 and 7, the front wheel drive force extraction shaft 29 and the mid-PTO shaft 19 are located at a lower position within the transmission case 8, and are located on one side of the transmission shaft 25 of the traveling system. They are installed at a slightly upper position on the other side and at a slightly lower position on the other side, and extend forward from the mission case 8 at these positions.

As shown in FIG. 3, the rear end of the transmission shaft 25 is connected to a support wall on the inner wall of the transmission case 8, and the rear end of the front wheel drive force output shaft 29 is connected to a support frame plate 60.
These shafts 2
A cover 64 supporting the front end portions of the supports 5 and 29 is mounted on the front surface of the support frame plate 60 using threaded bolts 66 that are screwed into threaded holes 65 shown in FIG. Then, inside this cover 64, the transmission shaft 2
5, and the gear 68 loosely installed on the front wheel drive force take-off shaft 29, and the gear 68 thereon is selectively moved onto the front wheel drive force take-off shaft 29. A front wheel drive clutch 70 for selectively connecting the front wheel drive force output shaft 29 to the transmission shaft 25 is constructed by providing a clutch hardware 69 for fixing the front wheel drive force output shaft 29 to the transmission shaft 25.

On the other hand, when viewed from the left and right, the front wheel drive force extraction shaft 29
The mid-PTO shaft 19, which is provided offset to the opposite side, is interlocked and connected to the second input shaft 23 in the following manner. In other words, the above
As shown in FIG. 3, the PTO switching clutch 36 is
In front of the PTO clutch 31, the clutch shaft 27
A gear 73 in which two gears 71 and 72 are loosely fitted with a space between them, and one of the gears 71 is fixedly installed on the intermediate shaft 28.
4 and 6, the other gear 72 is mounted on the idler shaft 30 as shown in FIGS.
An idler gear 75 is meshed with a gear 74 fixedly installed on the PTO shaft 19, and both gears 71 and 72 are meshed on the clutch shaft 27.
Clutch hardware 76 between, spline collar 77
Although it is configured to be able to slide freely through the shaft, it is not relatively rotatable. The outer circumferential surface of the spline collar 77 and the boss portions of the gears 71 and 72 extending in the direction of the collar 77 are provided with pawls that are aligned with each other, and the inner circumferential surface of the clutch hardware 76 is provided with pawls that align with each other. The clutch hardware 76 is formed with a pawl that can engage with these pawls, and the clutch hardware 76 is a pawl on the inner peripheral surface of the clutch metal fitting 76.
As shown in FIG. 3 and shown in phantom lines in FIG. 8a, the pawl of the spline collar 77 and both gears 71,
Both gears 71 and 72 are engaged with the pawl of 72.
and the position where both are connected to the clutch shaft 27, and the eighth
As shown by the solid line in FIG.
the position where only the clutch is connected to the clutch shaft 27, and the position where the
As shown in FIG. b, it is possible to engage the pawl of the spline collar 77 and the pawl of the gear 72 by sliding them to a position where only the gear 72 is coupled to the clutch shaft 27. Therefore, the PTO switching clutch 36 connects the clutch shaft 27 to the rear PTO shaft 1 at the clutch hardware 76 position shown in FIG.
7 and the rear PTO shaft 19, and at the clutch hardware 76 position shown in solid line in Fig. 8a, the rear PTO
It is connected only to the shaft 17 and, in the position shown in FIG. 8b, only to the mid-PTO shaft 19.
The gear train consisting of the gears 72, 75, and 74 described above is a mid-range gear train, as clearly shown in FIG.
It is provided in the transmission case 8, offset to the side where the PTO shaft 19 is located. That is, the mid-PTO shaft 19 is operatively connected to the second input shaft 23 via a gear train arranged in this manner and a PTO clutch mechanism 31, 36 including a PTO switching clutch 36.

Note that hydraulic oil is supplied to and discharged from the PTO clutch 31 through an oil passage (not shown) drilled in the clutch shaft 27 as usual.
As shown in FIG. 3, a rotary joint portion of the oil passage for connecting the oil passage, which is rotationally displaced together with the clutch shaft 27, to the oil passage on the fixed position side is integrally formed on the inner surface of the back wall of the transmission case 8. Projecting cylindrical part 7
An annular oil chamber 80 is formed by sealing an annular groove on the outer circumferential surface of the clutch shaft 27 by the inner circumferential surface of the clutch shaft 27 . A brake 81 having the cylindrical portion 79 as a brake case is also provided on the clutch shaft 27, and this brake 81 allows one and the other friction elements to slide freely between the clutch shaft 27 and the cylindrical portion 79. An oil chamber 8 is provided with a spring 83 that supports the friction element group and presses and engages the group of friction elements via the piston 82, and that applies hydraulic pressure for retracting the piston 82.
4 is provided. Oil chamber 8
4 is connected to an oil passage for supplying and discharging hydraulic oil to the PTO clutch 31, and the brake 81 is connected to the
When the PTO clutch 31, in which hydraulic pressure acts on the oil chamber 84, is activated, the hydraulic pressure causes the piston 82 to move backward to release the brake, and when the PTO clutch 31 is disengaged, the piston 82 moves forward due to the force of the spring 83, thereby braking the clutch shaft 27. It is said that

In FIG. 4, 85 and 86 are operating mechanisms for the vehicle speed change device 43 and the front PTO switching clutch 36, respectively, and in FIG. 7, 87 is an operating mechanism for the front wheel drive clutch 70. As shown in FIG. 5, the differential gear 44 is provided with a differential clutch 88 having a clutch metal fitting 88a slidably supported on the boss portion of the differential case 54.
The clutch hardware 88a, which is equipped with a pin 88b that selectively engages the driven bevel gear 56 on one side of the clutch gear 56 in a relatively non-rotatable manner, is displaced by an operating mechanism 89 shown in FIG.

The illustrated self-propelled work vehicle has a hydraulic transmission device 7 that performs stepless speed change including forward and backward switching of the vehicle,
The vehicle speed change device 43, which performs step-shifting, changes and controls the traveling direction and speed of the vehicle, and also engages the front wheel drive clutch 70 as necessary to drive the front wheels 1 for use in work. Using the PTO switching clutch 36, the rear PTO shaft 17 and the mid PTO
By driving one or both of the shafts 19, the mower M and another mower towed by a vehicle or a working machine such as a tiller can be driven alternatively or simultaneously;
The drive speed of the work implement towed by the vehicle can be changed to two speeds by the PTO transmission 32. Prior to operating the PTO switching clutch 36 or the PTO transmission 32, the PTO clutch 31 is disengaged by operating a directional control valve (not shown), and at this time the brake 81 brakes the clutch shaft 27 to shift the clutch. The inertial rotation of the shaft 27 is immediately stopped. The load of the spring 83 of the brake 81 is set to a relatively small value so as not to interfere with the shifting operations of the shift hardware 42 and the clutch hardware 76. Brake 81 is also PTO clutch 3
This prevents unexpected transmission from the transmission shaft 26 to the clutch shaft 27 due to oil dragging within the clutch 31 when the clutch 1 is disengaged.

Effects of the Invention The transmission of the present invention includes the left and right rear wheel drive shafts 57 extending left and right at a low level from inside the transmission case 8, and the rear PTO shaft 17 extending rearward at an intermediate level. In this structure, the input shaft 22 of the traveling system into the transmission case 8 and
The input shaft 23 of the PTO system is vertically disposed vertically to remove one constraint on the arrangement of the transmission between the travel system and the PTO system within the transmission case 8, and the rear wheel drive shaft 57 is rear PTO shaft 1
7, the PTO system input shaft 23 is placed on the upper side, and the PTO system clutch mechanism 31 is placed in the upper part of the transmission case 8. 36 and a transmission 32 are installed so as to be staggered in the front and back so that each does not interfere with the arrangement of the other side, and a transmission 43 and a differential 44 for the traveling system are installed in the lower part of the transmission case 8. , each one is installed in a staggered manner so as not to disturb the arrangement of the other side, and from the above, the inside of the mission case 8 is almost completely utilized effectively, and the mission case 8 is vertically long. It shall be possible to form it into a compact object.

In addition to the rear PTO shaft 17, this invention
The transmission case 8 is equipped with a mid-PTO shaft 19 that extracts the driving force for a low-level mid-mounted work machine installed at the bottom of the central part of the vehicle in the longitudinal direction.
The transmission device 43 and the differential device 4 of the traveling system are designed to extend directly forward from the lower level of the vehicle.
The mid-PTO shaft 19 is connected to a low-level part of the transmission case 8 in which the transmission gears 4 and 4 are arranged in the front and rear, and the mid-PTO shaft 19 is connected to the front side of the differential device 44 so as not to be restricted by the differential device 44, and also by the drive system transmission 43. The gear trains 72, 7 are disposed on the side of the transmission shaft 25 in the transmission 43 to prevent the transmission from occurring, and the gear trains 72, 7 transmit power to the mid-PTO shaft 19 on the side toward which the mid-PTO shaft 19 is located.
4, 75 are installed inside the transmission case 8, the mid-PTO shaft 19 and the gear trains 72, 74, 75 transmitting thereto can be installed without substantially increasing the dimensions of the transmission case 8. To increase the functions of a mission case and to make it a vertically long and compact mission case.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway schematic side view of a self-propelled working vehicle equipped with an embodiment of the present invention, FIG. 2 is a schematic plan view showing the arrangement of main parts of the working vehicle, and FIG.
The figure is a partially exploded longitudinal sectional side view of the main parts of the same work vehicle, Figure 4 is a longitudinal sectional view of only the main parts along the - line in Fig. 3, and Figure 5 is a cross-sectional plan view of the main parts of the same work vehicle. , 6th
The figure is a cross-sectional plan view of a part of the same work vehicle, and Figure 7 is a cross-sectional plan view of a part of the same work vehicle.
A vertical sectional view of only the main parts along the - line in the figure,
FIGS. 8a and 8b are vertical sectional side views respectively showing the main parts of FIG. 3 in different enlarged states. 1...front wheel, 2...rear wheel, 3...engine, 7
... Hydraulic transmission device, 8 ... Mission case, 1
1... Axle housing, 12... Rear wheel axle,
17...Rear PTO axis, 19...Mitsudo PTO axis,
22...first input shaft, 23...second input shaft,
24...Intermediate shaft, 25...Transmission shaft, 26...Transmission shaft, 27...Clutch shaft, 28...Intermediate shaft, 30
...Idler shaft, 31 ...PTO clutch, 32
...PTO transmission, 33, 34 ... Gear, 35
...Clutch housing, 36...PTO switching clutch, 37, 38...Gear, 39,40...
Gear, 42...Shift hardware, 43...Vehicle speed change device, 44...Differential gear, 45, 46...Gear, 4
7... Input bevel gear, 48... Bevel gear, 49... Gear, 50, 51... Gear, 53... Shift hardware,
54...Differential case, 55...Drive bevel gear,
56... Driven bevel gear, 57... Rear wheel drive shaft,
60... Support frame plate, 71, 72... Gear, 73...
Gears, 74, 75...Gears, 76...Clutch hardware.

Claims (1)

[Claims] 1 A first input shaft 22 that inputs running power into the transmission case 8 and a second input shaft that inputs working machine driving force.
The input shafts 23 are arranged along the front-rear direction, and the second input shaft 23 is arranged above and vertically offset from each other, so that the second input shaft 23 and The PTO clutch mechanisms 31, 36 and the PTO are connected between the rear PTO shaft 17 extending rearward from an intermediate level in the transmission case 8
The transmission device 32 is installed so that the PTO transmission device 32 is arranged at the rear side and is staggered from the front to the rear.
On the lower side of the PTO clutch mechanisms 31 and 36 and the PTO transmission 32, the vehicle speed transmission 43 is interposed between the first input shaft 22 and the left and right rear wheel drive shafts 57 extending left and right from a low level inside the transmission case 8. The differential device 44 is disposed on the rear side and installed so as to be staggered in the front and rear, and the mid-PTO shaft 19 extending forward from a low level in the transmission case 8 is connected to the differential device. The PTO clutch mechanisms 31 and 36 are disposed in the transmission case 8 on the side of the speed change shaft 25 of the vehicle speed change device 43 on the front side of the transmission mechanism 44, and the PTO clutch mechanisms 31 and 36 are connected to the rear PTO shaft 17 and the mid PTO shaft. 19 and a PTO switching clutch 36 capable of selectively switching and transmitting the working machine driving force to the above-mentioned mid-PTO.
The shaft 19 is moved to the side where the mid-PTO shaft 19 is located and is connected to the second input shaft 23 via the gear trains 72, 74, 75 provided in the transmission case 8 and the PTO clutch mechanisms 31, 36. A transmission for a self-propelled work vehicle that is characterized by being interlocked and connected to.