JPH07335Y2 - Hydraulic circuit structure of tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a hydraulic circuit structure of a tractor.

(Prior Art) In an agricultural tractor, an engine, a transmission case, etc. are joined in the front-rear direction to form a tractor vehicle body, a hydraulic pump is provided on the engine side, and a hydraulic clutch such as a forward / reverse switching device is incorporated in the transmission case. In addition, a hydraulic device for raising and lowering the work equipment is installed at the rear of the mission case, and a specified amount of oil is sent preferentially from the hydraulic pump to the control valve of the hydraulic clutch via the priority valve and from the priority valve to the control valve of the hydraulic device. There is something I tried to send.

In this case, conventionally, a control valve for the hydraulic clutch has generally been arranged above the tractor vehicle body, and a priority valve has generally been arranged at one side below the tractor vehicle body.

(Problems to be solved by the invention) In the conventional structure, a pipe connecting the priority valve and the hydraulic clutch control valve needs to be provided in the vertical direction, and at the same time, a pipe connecting the control valve and the hydraulic clutch is provided. However, there is a drawback that the piping structure outside the mission case becomes complicated. Further, the pipe path of the pipe becomes long, and there is a problem of interference with other components.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and an object of the present invention is to shorten a piping path and simplify an external structure.

(Means for Solving the Problems) As a means for solving the problems, the present invention constructs the tractor vehicle body 1 by joining the engine 2 and the transmission case 4 in the front-rear direction, and the step 1 is provided on both left and right sides of the tractor vehicle body 1.
5, hydraulic devices 12 for raising and lowering the working machine are provided at the rear portions, hydraulic clutches 28 and 29 are provided in the transmission case 4, and the hydraulic device 1 from the hydraulic pump 18 on the engine 2 side through the pipes 20 and 23.
2 and the hydraulic clutches 28,29 in the tractor configured to send oil to the control valves 13,21, the pipes 20,23 are provided on one side of the tractor vehicle body 1 on the lower side of the step 15 along the tractor vehicle body 1 The control valve 21 for the hydraulic clutches 28, 29 connected in the middle of the pipes 20, 23 is attached to the outside of the mission case 4 so as to correspond to the partition wall 41 in the mission case 4, and the control is performed. Hydraulic clutch 2 from valve 21
Oil passages 72, 73 for sending oil to 8, 29 are formed in the partition wall 41.

(Embodiment) The present invention will be described in detail below with reference to the illustrated embodiment.
In the figure, reference numeral 1 denotes a tractor vehicle body, which is formed by joining an engine 2, a clutch housing 3, and a transmission case 4 in the front-rear direction, and has a front wheel 5 and a rear wheel 6. A main clutch 7 is incorporated in the clutch housing 3, and a hydraulic clutch type forward / reverse switching device 8 and a transmission device linked thereto are incorporated in the transmission case 4. Reference numeral 9 is a hood that covers the engine 2, etc., 10 is an instrument panel provided behind the hood 9, and 11 is a handle. A hydraulic device 12 for raising and lowering the working machine has a control valve 13. 14 is a driver's seat. Reference numeral 15 denotes a step, which is attached to the left and right sides at the center of the tractor body 1 in the front-rear direction. Reference numeral 16 denotes a pair of left and right brake petals, which are supported by a pedal shaft 17 which is horizontally mounted on the lower end portion of the mission case 4. Reference numeral 18 denotes a hydraulic pump mounted on the engine 2, which sucks the lubricating oil in the transmission case 4 through a pipe 19 and discharges it to the pipe 20 side.

Reference numeral 21 is a control valve for controlling the forward / reverse switching device 8, 22 is a priority valve, and the oil from the pipe 20 is preferentially sent to the control valve 21 by a predetermined amount, and the rest is supplied to the hydraulic device 12 via the pipe 23. The control valve 21 and the priority valve 22 are provided to one side of the tractor body 1 below the step 15 for sending to the control valve 13. The pipes 19, 20 and 23 are arranged at the lower part of one side of the tractor body 1 along the front-rear direction, and the front ends of the pipes 19 and 20 stand upright on the hydraulic pump 18 and the rear end of the pipe 23. The sides stand upright and are connected to the control valves 13, respectively.

A forward / reverse switching device 8, a forward gear train 25 and a reverse gear train 26 interlocked with a main shaft 24 as shown in FIG. 1, and a forward hydraulic clutch 28 for selectively connecting the gear trains 25, 26 to a transmission shaft 27. And a reverse hydraulic clutch 29. The hydraulic clutches 28 and 29 are a cylinder body 30 fixed to the transmission shaft 27.
When the pressure oil is supplied from the oil passages 31 and 32 of the transmission shaft 27 to the cylinder chambers 33 and 34, the pistons 35 and 36 press the clutch plates 37 and 38, and the gear trains 25, 26 gears 39,4
0 is connected to the transmission shaft 27 via the cylinder body 30. The transmission shaft 27 includes a partition wall 41 for partitioning the clutch housing 3 and the transmission case 4 and a partition wall 42 behind the partition wall 41.
Is rotatably supported by bearings 45, 46 across the shaft, and a rotary joint 48 for sending oil to the oil passages 31, 32 and the oil passage 47 for lubrication is provided on the front end side of the transmission shaft 27. Its rotary joint 48
Is attached to the partition wall 41 from the clutch housing 3 side.

As shown in FIGS. 1 to 3, the control valve 21 has a valve body 49.
It is a rotary type in which a spool 50 is rotatably rotatable about its axis, and is detachably attached to the outside of the mission case 4 by a bolt 52 at a position corresponding to the partition wall 41 via a spacer 51. Outside the valve body 49 of the control valve 21, the priority valve 22
Are detachably attached by bolts 53. Control valve 21
The spool 50 projects forward from the valve main body 49, and a lever 54 is fixed to the front end of the spool 50. A rod 55 is connected to the lever 54 so that the lever 54 can be rotated up and down,
The rod 55 extends upward along the tractor body 1 and is connected to a relay lever 57 pivotally supported by a support shaft 56 in the instrument panel 10. The relay lever 57 is arranged near the side of the handle 11 and is connected via a rod 59 to a forward / rearward travel switching lever 58 which can be operated in the front-rear direction around the vertical axis. Therefore, by operating the forward / backward movement switching lever 58 back and forth, the rod 59, the relay lever 57, the rod 55, and the lever
The spool 50 rotates via 54, and the control valve 21 switches between forward and reverse.

The spacer 51 has a plate-like shape. As shown in FIG. 4, the spacer 51 has a forward port 60 and a backward port 6 on the valve body 49 side of the control valve 21.
1, a forward oil passage 64, a reverse oil passage 65, a lubricating oil passage 66, and a drain oil passage 67, which communicate with the lubrication port 62 and the drain port 63, respectively, and the openings 68 to 71 of the respective oil passages 64 to 67 are formed. Are formed in a row at predetermined intervals in the vertical direction within the thickness of the partition wall 41 in the front-rear direction. On the other hand, in the partition wall 41, as shown in FIGS. 1 and 2, oil passages 72 to 75 communicating with the openings 68 to 71 are formed laterally toward the rotary joint 48, and the oil passages are formed.
72-74 are connected to the oil passages 76-78 of the rotary joint 48, respectively.
75 communicates with the inside of the mission case 4 and is opened. The priority valve 22 is connected to the pipe 20 through the joint 79 on the front side.
However, the pipes 23 are connected to the lower surface side via joints 80, respectively.

In the above configuration, when the hydraulic pump 18 rotates, the pipe
The oil in the mission case 4 is sucked in via 19 and the pipe 20
To the priority valve 22 via. Then, the priority valve 22 preferentially sends a predetermined amount of oil to the control valve 21, and when the control valve 21 is neutral, the oil returns from the drain port 63 through the drain passage 67 and the oil passage 75 into the mission case 4. Priority valve 22 for remaining oil
Is sent to the control valve 13 of the hydraulic device 12 via the pipe 23.

When the forward / reverse switching lever 58 is operated to the forward or reverse side, the spool 50 of the control valve 21 rotates, the control valve 21 switches to the forward or reverse, and the forward port 60 or the reverse port 61 causes the oil passage 6 to pass.
Since the pressure oil is sent to the cylinder chamber 33 or 34 of the forward / reverse switching device 8 through 4,72,31 or the oil passages 65,73,32, the forward hydraulic clutch 28 is connected to the reverse hydraulic clutch 29.

Since the control valve 21 is located outside the mission case 4 and is connected to the hydraulic clutches 28 and 29 via oil passages 72 and 73 formed in the partition wall 41, the control valve 21 and the hydraulic clutches 28 and 29 are piped. Since the control valve 21 and the priority valve 22 are connected to each other, there is no need for a pipe or the like between them, and therefore the piping outside the mission case 4 can be shortened. Moreover, since the control valve 21 and the priority valve 22 are on the lower side of step 15, they do not hinder the operator. Further, since the pipes 19, 20, 23 are in the front-rear direction near one side of the lower part of the tractor body 1, and the control valve 21 and the priority valve 22 are arranged there, the pipes 20, 23 are arranged on the upper side of the tractor body 1. There is no need to extend the length of the piping, and therefore the length of the piping path can be kept to the minimum necessary, and the external piping for the control valve 21 and the hydraulic clutches 28, 29 is not necessary, and the external structure can be improved. It can be greatly simplified.

The spacer 51 may be omitted. Further, instead of the priority valve 22, a mere distribution valve may be used.

According to the present invention, the pipes 20 and 23 are arranged on one side of the tractor body 1 below the step 15 in the front-rear direction along the tractor body 1, and in the middle of the pipes 20 and 23. The control valve 21 for the connected hydraulic clutches 28, 29 is attached to the outside of the mission case 4 so as to correspond to the partition wall 41 in the mission case 4, and the oil is sent from the control valve 21 to the hydraulic clutches 28, 29. Since the passages 72 and 73 are formed in the partition wall 41, the piping path outside the mission case 4 becomes shorter than the conventional one, and the external structure can be simplified. Further, since the control valve 21 for the hydraulic clutches 28 and 29 is located below step 15, this does not hinder the operator.

[Brief description of drawings]

The drawings illustrate one embodiment of the present invention. Fig. 1 is a fragmentary plan view of essential parts, Fig. 2 is a fragmentary front view of Fig. 3, Fig. 3 is a side view of the same, and Fig. 4 is a sectional view of a spacer. FIG. 5 is a side view of the tractor. 1 ... tractor body, 2 ... engine, 4 ... mission case, 8 ... forward / reverse switching device, 12 ... hydraulic device, 1
3,21 …… Control valve, 15 …… Step, 19,20,23 …… Pipe, 22 …… Priority valve, 28 …… Forward hydraulic clutch, 29 …… Reverse hydraulic clutch, 41 …… Bulk, 72,73 …… Oil passage.

Claims (1)

[Scope of utility model registration request] 1. A tractor vehicle body 1 is constructed by joining an engine 2 and a transmission case 4 in the front-rear direction, step 15 is provided on both left and right sides of the tractor vehicle body 1, and a hydraulic device 12 for raising and lowering a working machine is provided at a rear portion thereof. The hydraulic clutches 28 and 29 are provided in the transmission case 4, and the hydraulic device 12 and the hydraulic clutches 28 and 29 are passed from the hydraulic pump 18 on the engine 2 side to the pipes 20 and 23.
In the tractor configured to feed oil to the control valves 13 and 21 of the tractor, the pipes 20 and 23 are connected to the step 15
The hydraulic clutches 28, which are arranged in the front-rear direction along the tractor body 1 on the lower side of the
A control valve 21 for 29 is attached to the outside of the mission case 4 so as to correspond to the partition wall 41 in the mission case 4, and oil passages 72, 73 for sending oil from the control valve 21 to the hydraulic clutches 28, 29.
Is formed on the partition wall 41, and a hydraulic circuit structure for a tractor.