JPH0721377Y2 - Transmission device for work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a transmission device for transmitting a traveling driving force and a working machine driving force in a relatively small work vehicle such as a mower tractor.

[Conventional technology and its problems]

In a work vehicle, a hydraulic power transmission device for continuously changing the vehicle speed is generally a hydraulic pump and a hydraulic motor of which both are arranged in the front-rear direction. That is, the hydraulic pump and the hydraulic motor may be installed in a concentric arrangement along the front-rear direction (see, for example, Japanese Patent Publication No. 50-33283), or may be installed in a vertical arrangement (for example, Japanese Patent Publication No. 1-17).
(See Japanese Patent Laid-Open No. 883219), and it has been arranged side by side (see, for example, Japanese Patent Laid-Open No. 63-258219).

On the other hand, a transmission device equipped with a hydraulic rolling device in which a hydraulic pump is provided in the front-rear direction and a hydraulic motor is provided in the rear position along the left-right direction is disclosed in Japanese Utility Model Publication No. 56-2573. Has been done.

According to the present invention, all the gears of the transmission mechanism that are transmitted from the motor shaft of the hydraulic motor to the left and right drive wheel shafts can be spur gears. That is, according to the structure in which the hydraulic motor is provided along the front-rear direction as described above, a pair of bevel gears is indispensable regardless of the transmission from the motor shaft along the front-rear direction to the drive wheel shaft along the left-right direction. On the other hand, since the motor shaft and the drive wheel shaft are parallel to each other in the left-right direction, it is not necessary to use a bevel gear. The transmission part by a pair of bevel gears meshing with each other becomes expensive especially when trying to obtain the deceleration along with the change of the transmission direction, and the transmission efficiency is not fixed,
The effect of eliminating the bevel gear is hard to ignore.

According to Japanese Utility Model Publication No. 56-2573, on the other hand, there is a drawback that the pump shaft of the hydraulic transmission cannot be used as the driving shaft for the PTO shaft for driving the working machine. That is, among the aforementioned publications, those disclosed in Japanese Examined Patent Publication No. 1-17883 and Japanese Patent Laid-Open Publication No. 63-258219 each extend the pump shaft of the hydraulic transmission device that receives input conduction from the engine to the rear side, While it is decided to transmit from the pump shaft to the PTO shaft for driving the working machine, in the Japanese Utility Model Publication No. 56-2573, the hydraulic motor on the rear side interferes with the PTO shaft from the rear end of the pump shaft. This is because the driving force for

In the transmission disclosed in Japanese Utility Model Publication No. 56-2573, a traveling system guided in the hydraulic transmission direction using two transmission shafts parallel to the input shaft or the main shaft of the transmission case which receives the input conduction from the engine. The power transmission path of the PTO system and the power transmission path of the PTO system guided in the PTO axial direction are distributed, but this increases the number of power transmission shafts, which is undesirably decided in terms of cost and compactness of the transmission device.

[Invention task]

Therefore, this invention makes it possible to transmit from the motor shaft of the hydraulic transmission to the left and right drive wheel shafts by a transmission mechanism using only spur gears, and at the same time, to set the pump shaft of the hydraulic transmission to the PTO.
It is intended to solve the above-mentioned problems by making it usable as a driving shaft of a system.

[Means for solving problems]

To this end, the present invention, in a transmission device for a work vehicle as shown in the accompanying drawings, controls steplessly the vehicle speed in the upper half of a transmission case 2 equipped with left and right rear wheel axles 1. The hydraulic transmission 3 is installed with the hydraulic pump 4 of the hydraulic transmission 3 along the front-rear direction and the hydraulic motor 5 behind the hydraulic pump 4 along the left-right direction, and the motor shaft 5a of the hydraulic motor 5 is installed. The lower half of the transmission case 2 is connected to the left and right rear wheel axles 1 by a spur gear transmission mechanism 6, while the PTO shaft is projected from the inside of the transmission case 2 to the outside along the front-rear direction. A PTO clutch 9 and another spur gear transmission mechanism 10 for connecting the pump shaft 4a of the hydraulic pump 4 to 7, 8 are arranged in the mesh case 2 on the front end of the pump shaft 4a. The other spur gear transmission 10 is It is arranged and provided at the front end in the case 2.

[Function and effect of device]

From the motor shaft 5a of the hydraulic motor 5 located rearward and along the left-right direction in the hydraulic transmission 3, the left and right rear wheel axles 1
In contrast, the traveling drive force can be transmitted by a transmission mechanism that uses only spur gears as a transmission gear, and the lower half of the transmission case 2 has a front end where the PTO gear transmission mechanism 10 is arranged. Since it is open except for the side part,
Although the motor shaft 5a is supposed to be arranged on the relatively rear side, the rear end axle 1 is arranged on the front side as much as possible with respect to the motor shaft 5a, and the transmission path between the motor shaft 5a and the rear wheel axle 1 is lengthened. By virtue of the spur gear transmission mechanism 6 that uses only spur gears that are cheaper than the bevel gears, it is possible to obtain a significant reduction in speed that greatly increases the axle drive torque.

In addition, the pump shaft 4a of the hydraulic pump 4 in the mission case 2
Pump shaft 4a from the front end through PTO clutch 9 above it.
Similarly, the PT transmitted to the PTO shafts 7 and 8 along the front-rear direction
The O-type spur gear transmission mechanism 10 can be compactly provided by vertically arranging it in a space with a small front-rear width at the front end of the mesh case 2.

Therefore, according to the present invention, in the transmission device using the hydraulic transmission, the above-mentioned drawbacks of the prior art can be overcome, and the cost reduction and the compactness of the device can be achieved.

〔Example〕

In the illustrated embodiment, as shown in FIG.
The present invention relates to an example in which the present invention is implemented in a mower tractor in which a mower M is provided between the 11 and the rear wheel 12 on the lower surface of the body.

The engine 13 is mounted on the front of the machine body, and a transmission shaft 14 for transmitting from the engine 13 to the inside of the case 2 disposed between the left and right rear wheels 12 is provided along the front-rear direction. As the PTO shaft, a rear PTO shaft 7 protruding rearward from the inside of the case 2 for driving a working machine such as a glass collector or a rotary cultivator to be pulled to the rear of the machine body, and a mower via a transmission shaft 15. Gearbox M of M
A mixed PTO shaft 8 used to transmit the mower driving force is provided to a.

As shown in FIG. 1-3, the mission case 2 is closed on one side by a side plate 17 for installation, and on the rear half of the upper end by a thick lid plate 18. Each has a built-in opening. Input conduction into the motion case 2 may be performed directly to the pump shaft 4a, but in the illustrated example, the shaft holder mounted on the front wall of the motion case 2
The short input shaft 20 supported by 19 is provided, and this input shaft 20
The front end of the pump shaft 4a is connected to the transmission shaft 14 shown in FIG. 5, and the front end of the pump shaft 4a is spline-fitted to the input shaft 20 having the latter half hollow and a spline formed on the inner surface. It is adapted to obtain an input conduction into the case 2.

The hydraulic transmission 3 is attached to the cover plate by bolts 22 shown in FIG.
The base 23 is provided on the front surface of the base 18, and the hydraulic pump 4 is arranged on the front surface of the base 23, and the hydraulic motor 5 is arranged so as to be offset to one side in the mesh case 2. It is attached to the inner side surface of each. As shown in FIG. 3, the hydraulic pump 4 has a pair of oil supply / discharge ports 4A and 4B which are opened on the front surface of the base 23, and the hydraulic motor 5 is provided with a base 23 of the base 23 as shown in FIGS. It has a pair of oil supply / drain ports 5A, 5B opened on the inner side surface. The oil supply / discharge ports 4A, 5A and 4B, 5B are connected to each other by a pair of oil supply / discharge passages (not shown) provided in the base 23. The hydraulic pump 4 is of a variable displacement type as usual, and its volume is controlled to be changed by changing the pump swash plate 4b by the rotational displacement operation of the operating shaft 24 shown in FIG. As shown in FIG. 1, a charge pump 25 for supplying hydraulic oil to the oil supply / discharge passage between the hydraulic pump 4 and the hydraulic motor 5 uses a base 23 as a pump case and a cover plate 18 as a case cover. The hollow pump shaft 25c of the toroidal type used for the pump shaft 4a of the hydraulic pump 4 inside the base 23.
It is supposed to be driven by. On the back surface of the cover plate 18, a working machine pump 27 for supplying hydraulic oil to a working machine cylinder 26 (FIG. 5) for lifting and lowering the working machine connected to the rear part of the machine body is mounted. , Its pump shaft 27a
Is connected to the pump shaft 25c of the charge pump 25.

As shown in FIGS. 1 and 3, an intermediate shaft 28 and a speed-change shaft 29, which are arranged in the left-right direction in the same way as the motor shaft 5a and the rear wheel axle 1, are provided in the lower half portion of the transmission case 28. Is positioned in the middle between the rear wheel axle 1 and the motor shaft 5a when viewed in the front-rear direction or in the vertical direction, and the transmission shaft 29 is positioned immediately below the motor shaft 5a at substantially the same level as the rear wheel axle 1. And it is provided.
Further, a differential gear 30 is arranged between the left and right rear wheel axles 1, and the differential gear 30 is additionally provided with a defrost clutch 31.

To explain the specific structure of the spur gear transmission mechanism 6 that connects the motor shaft 5a to the left and right rear wheel axles 1, the motor shaft 5a meshes a small spur gear 33 on it with a large spur gear 34 on the intermediate shaft 28. It is supposed that the intermediate shaft 28 is decelerated. Two spur gears 35 and 36 are loosely fitted and installed on the intermediate shaft 28, and two spur gears 37 and 38 meshing with these spur gears 35 and 36 are fixedly set on the transmission shaft 29. ing. Spur gears 35 and 36 are shifter sleeves 3
By means of 9, the intermediate shaft 28 can be selectively coupled to each other, whereby the transmission shaft 29 is driven by the intermediate shaft 28 at two rotation speeds accompanied by deceleration. There is. Then, a small spur gear 40 integrally formed with the transmission shaft 29 is meshed with a large spur gear 41 which is an input gear of the actuating device 30 to obtain the drive of the left and right rear wheel axles 1. A traveling brake 42 is attached to the transmission shaft 29 in a brake case 2a which is integral with the transmission case 2.

As shown in FIG. 1, the PTO clutch 9 has a pump shaft 4a.
A friction multi-plate type in which a clutch housing 44 fixedly installed on the front end of the and a spur gear 45 loosely fitted on the pump shaft 4a on the rear side of the clutch housing 44 support friction elements addressed to a plurality of slides only freely. It is composed of a hydraulic clutch. An oil passage 46 for supplying / discharging hydraulic oil to / from the PTO clutch 9 is provided on the pump shaft 4a.
The annular oil chamber 47 that forms the rotary joint portion of the oil passage that connects the oil passage for hydraulic oil on the position fixed side to the oil passage 46 has an annular recess formed on the outer peripheral surface of the pump shaft 4a. The groove is provided by sealing the inner peripheral surface of the shaft insertion hole at the front end of the pump case of the hydraulic pump 4.

The PTO clutch 9 is provided with an anti-rotation brake 48 for preventing the clutch driven side from entraining when the clutch 9 is cut. This brake 48 is a piston 48a in a cylinder hole formed in the pump case. Has a brake shoe 48b that is attached to the piston rod of the above and is opposed to the boss portion of the spur gear 45. The piston 48a is biased by a spring 48c in a direction in which the brake shoe 48b is brought into pressure contact with the boss portion of the spur gear 45 to operate the brake 48, and the piston 48a is hydraulically operated on the front side of the piston 48a. An oil chamber 48d for retracting and releasing the brake 48 is provided.

Similarly, as shown in FIG. 1, the rear PTO shaft 7 and the mixed PTO shaft 8 are provided so as to be concentric with each other. A transmission shaft 50 extending along is provided so as to be substantially in contact with both PTO shafts 7 and 8. And, in the case of the STO gear transmission mechanism 10 of the PTO system, in the illustrated case, a larger diameter spur gear 51 meshed with the spur gear 45 on the front end portion of the pump shaft 4a is fixedly installed on the transmission shaft 50, It is configured. On the rear PTO shaft 7 and on the mixed PTO shaft 8
Each of these PTOs is in the case 2 above.
A rear PTO clutch 52 and a mixed PTO clutch 53 are provided which selectively connect the shafts 7, 8 to the transmission shaft 50.

In the structure in which only the rear PTO shaft 7 is provided as the PTO shaft, the rear PTO shaft 7 is extended forward or the transmission shaft corresponding to the transmission shaft 50 is connected to the rear PTO shaft 7 and then the spur gear 51 is supported. The spur gear of is fixedly installed, and the rear PTO clutch is not provided.
On the contrary, in the structure in which only the mixed PTO shaft 8 is provided, the spur gear 51
The corresponding spur gear is fixedly installed on the Mitsu PTO shaft 8 and the Mitsu PTO clutch is not provided.

The lower portion of the mesh case 2 is also used as an oil tank, and oil suction passages 55, 56, 57 for guiding oil from the lower portion of the mesh case 2 to the charge pump 25 are shown in FIG. The charge pump 25 provided in the lower half back wall of the mission case 2, in the lid plate 18 and in the base 23 as shown in FIG.
Is communicated with the suction port 25a. Similarly, the discharge port 25b of the charge pump 25 provided on the base 23 is guided by the oil passage 58 in the base 23 in the direction of the pair of oil supply / discharge passages (not shown) between the hydraulic pump 4 and the hydraulic motor 5. Has been.

Charge pump 2 for supplying hydraulic oil to PTO clutch 9
Similarly, as shown in FIG. 1, the oil passages 59 and 60 for connecting the oil passage 58 to the annular oil chamber 47 from the middle thereof are provided in the base 23 as shown in FIG. It is formed in the pump case of the hydraulic pump 4. A directional valve 61 for the PTO clutch 9 is inserted and installed in the middle of the oil passage 59. At the position shown in the drawing, this directional control valve 61 connects the oil passage 59 on the secondary side of the valve 61 to the tank port 62 that opens to the inside of the mesh case 2 to cut the PTO clutch 9 and cut the plate on the upper surface of the mesh case 2. Operating rod 64 held by member 63
PTO clutch 9 when slightly pushed in from the position shown by
It is configured to guide the hydraulic oil in the direction to engage the clutch 9 with the clutch. In the pump case of the hydraulic pump 4, the anti-rotation brake 48 described above is provided in the middle of the oil passage 60.
The oil chamber 48d is communicated with the oil chamber 48d, and when the clutch of the PTO clutch 9 is engaged, the oil pressure is supplied to the oil chamber 48d and the anti-rotation brake 48 is released.

In FIG. 2, reference numeral 66 is a relief valve inserted and installed in an oil passage 67 for communicating the inside of the oil passage 59 on the secondary side of the directional control valve 61 with the inside of the case 2, and sets the working hydraulic pressure for the PTO clutch 9. It is for. Also, in Figures 1 and 3, 68
Is a pair of check valves inserted in a pair of communication passages for communicating the oil passage 58 shown in FIG. 1 with the pair of oil supply / discharge passages between the hydraulic pump 4 and the hydraulic motor 5. When a mower tractor shown in FIG. 5 is pulled and moved by another vehicle, which is held by the plate member 63 by a pair of opening actuating rods for opening (not shown above). In addition, it is used for draining hydraulic oil from the hydraulic transmission 3.

FIG. 4 shows the manner in which the transmission mechanism is incorporated into the upper half of the mission case 2.
The hydraulic pump 4 and the PTO clutch 44 and the gear 45 of the PTO system are mounted on the front side of 23, and the lid plate 18 on which the working machine pump 27 is mounted is mounted on the rear side of the base 23 as shown in FIG. bolt
The assembly mounted by means of 22 is obtained by assembly outside the case 2, and the plate member 63 is not attached to the case 2 and the assembly is attached to the back wall of the case 2. The upper end of the pump shaft 4a is inserted into the mesh case 2, the front end of the pump shaft 4a is inserted into the hollow part of the input shaft 20 and spline-fitted, and the cover plate 18 is fitted with the rear end flange 18a of the mesh case. The mounting is done by mounting it on 2. The hydraulic motor 5 is then
From the opening on the side plate 17 side shown in FIGS.
It is inserted inside and mounted on one side of the base 23. In FIG. 4, reference numerals 70 and 71 respectively denote a bearing hole formed on the base 23 for the end of the motor shaft 5a and a mounting hole for the hydraulic motor 5.

The mower tractor shown in FIG. 5 drives the vehicle by driving the rear wheels 12 to control the vehicle speed steplessly by controlling the tilt angle of the pump swash plate 4b of the hydraulic transmission 3, and the shifter sleeve 39 shown in FIG. It is used for lawn mowing and other work while controlling the vehicle speed to two levels, high and low by changing the position.

When the lawn mowing work with the mower M is put in the Mitsu PTO clutch 53, at the same time, when collecting the lawn mowed by the grass collector to be pulled to the rear of the vehicle, the rear PTO is used.
Clutch 52 can also be inserted. When working with a rotary cultivator that is towed to the rear of the vehicle, or when using stationary control equipment that uses the rear PTO shaft 7 as a drive source, the rear PTO clutch 5
Only 2 can be entered. Rear PTO clutch 52 or Mitsu PTO
Prior to the operation of the clutch 53, the hydraulic multi-plate PTO clutch 9 is temporarily turned off to facilitate the operation and protect the clutch member.

[Brief description of drawings]

FIG. 1 is a partially developed vertical side view of one embodiment, FIG. 2 is a partially developed vertical plan view of the same embodiment, and FIG. 3 is III-III of FIG.
FIG. 4 is a cross-sectional view substantially along the line, FIG. 4 is a vertical cross-sectional side view showing an assembling mode of a transmission mechanism, and FIG. 5 is a partially cutaway schematic side view of a mower tractor equipped with an embodiment. 1 ... Rear wheel axle, 2 ... Mission case, 3 ... Hydraulic transmission device, 4 ... Hydraulic pump, 4a ... Pump shaft, 5 ...
Hydraulic motor, 5a …… Motor shaft, 6 …… Spur gear transmission mechanism,
7 …… Rear PTO shaft, 8 …… Mid PTO shaft, 9 …… PTO clutch, 10 …… Spur gear transmission, 20 …… Input shaft, 23 …… Base, 28 …… Intermediate shaft, 29 …… Shift Axis, 30 ... Differential, 3
3,34 …… Spur gears, 35,36,37,38 …… Spur gears, 39 …… Shifter sleeves, 40,41 …… Spur gears, 44 …… Clutch housing, 45 …… Spur gears, 50 …… Transmission Shaft, 51 ... Spur gear, 52
…… Rear PTO clutch, 53 …… Mitsu PTO clutch.

Claims (1)

[Scope of utility model registration request] 1. A hydraulic transmission device 3 for steplessly changing and controlling a vehicle speed in an upper half of a transmission case 2 equipped with left and right rear wheel axles 1, and a hydraulic pump 4 of the hydraulic transmission device 3. The hydraulic motor 5 and the hydraulic pump 4
Of the hydraulic motor 5 is connected to the left and right rear wheel axles 1 by the spur gear transmission mechanism 6 in the lower half portion of the transmission case 2,
The pump shaft 4a of the hydraulic pump 4 is opposed to the PTO shafts 7 and 8 which are projected from the inside of the case 2 along the front-rear direction to the outside.
PTO clutch 9 and other spur gear transmission mechanism for connecting to
0, PTO clutch 9 is arranged on the front end of the pump shaft 4a in the mesh case 2, and the other spur gear transmission mechanism 10 is arranged at the front end of the mesh case 2. Transmission device for work vehicles.