JPS586245Y2 - Nouyou Tractor - Touniokeru Yuatsusouchi - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a hydraulic system for an agricultural tractor.

In other words, in an agricultural tractor in which a lift arm for raising and lowering a rear-mounted working machine is driven by a hydraulic cylinder, a stop pulp and a relief valve that can be hydraulically locked are mounted on the head of the hydraulic cylinder, making it easy to manufacture. In addition, the relief valve is designed to efficiently and safely operate the hydraulic pressure at the head, and the lift arm can be reliably locked by operating the stop pulp that keeps the lift arm stopped. It is provided by

Next, the embodiment shown in the drawings will be described.

FIG. 1 shows a side view of an agricultural tractor, in which a rotary working machine 4 is attached to the rear of a rear case 2 on which two rear wheels 1 are mounted via a three-point link mechanism 3, and a rotary working machine 4 is attached to the side of the working machine 4. There is a sled-shaped sensor 5 that can move up and down by being pressed against the ground side.
are installed in order to operate the depth control, and are connected so that the rotary work machine 4 can be raised and lowered by raising and lowering a hydraulic lift arm 7 installed in a hydraulic case 6 fixed above the rear case 2. A working machine 9 such as a front loader located in front of the wheels 8 is removably mounted on the agricultural tractor, and the mounting structure is such that it can be operated by a hydraulic mounting 10.

Note that S is a seat disposed on the hydraulic case 6.

A piston 12 is fitted into a hydraulic cylinder 11 in the front-rear direction of the hydraulic case 6 mounted on the upper part of the rear case 2, and a rod 13 of the piston 12 is connected to an arm coaxially fixed with the hydraulic lift arm 7. Similarly to the structure, the hydraulic lift arm 1 is configured to be able to freely rotate up and down by the reciprocating movement of the piston 12, and the spool end protrudes rearward from within the hydraulic control valve 14 fixed above the front part of the hydraulic case 6. and configure it.

An operating lever 11 is provided on the right side of the hydraulic case 6 along a guide plate 15 and rotated around a support shaft 16. A pin 18 is fixed to the circumferential surface of the support shaft 16, and an operating lever 19 is attached to the pin 18. The lower front surface of the operating lever 19 is brought into contact with the end surface of the spool end, and the other end of the tension spring 20, which is attached to the upper part, is attached to the locking tool 21 above the rear of the hydraulic case 6, A pin 24 is installed on the periphery of the large-diameter shaft cylinder 2, which is installed eccentrically rearward with respect to the axis of the support shaft 16.
is fixed so that the pin 24 is connected to the operating lever 1 above the support shaft 16.
A wire 26 connected to the lower end of the feedback lever 25 whose upper end is fixed to the extended end of the operating shaft 22 is connected to the sensor 5 side so that the sensor 5 is on the ground side. The wire 26 is provided so that it is sub-actuated rearward when the work equipment is lowered (when the lifting height of the work equipment becomes high), and the central pin 2 of the feedback lever 25 is
A stopper 29 is provided at the end of the rod 28 that is slidably inserted into the hydraulic lift arm 7. 30 and the depth control hole 31 can be selectively engaged.

Both ends of the valve hole A in the hydraulic control valve 14 are closed by a support metal 32 and a plug body 33, and the spool B is movably fitted in the valve hole A, but the spool end protrudes from the plug body 33. The spool end portion is provided so as to face the operating lever 19, and to be pressed in the direction in which the spool end portion protrudes by the elastic force of the compression spring 34 inserted into the support metal 32.

In the valve hole A, grooves 35, 36, 37, 38, and 39 are provided on the inner circumferential surface of the valve hole A with gaps in the front-rear direction. Lands AI, A2. A3. On the other hand, lands 40, 4 are formed on the outer periphery of spool B at intervals in the front and rear direction.
1 and 42 and formed in the spool B.
4 has a support 45 closed at one end with a retaining ring 45 and an O-ring 45 as a liquid layer, and a compression spring 46 supported by the support 45 supports a steel ball 4T to form a check valve. A passage 48 is formed in the part of the spool B which constitutes the check valve C and communicates with the check valve C, and a passage 49 which opens on the outer circumference is formed in the shaft hole 44, and a high pressure oil supply pipe 50 from the hydraulic pump side is formed.
is connected to the high pressure port 51 on the upper part of the valve to communicate the high pressure port 51 with the groove 38, and a slow return valve 52 is interposed on the outer periphery of the groove 37 so as to freely adjust the flow rate.
A passage 53 communicating with the valve 52 and the groove 35 is formed in the lower part of the control valve 14, and a drain passage 54 communicating with the passage 53 is formed so as to communicate from inside the hydraulic case 6 to the lower rear case (tank).

At the front part of the hydraulic case 6 below the control valve 14, a head part 11a is fitted together with an 01J ring 11b, and fitted to the hydraulic cylinder 11 with four bolts inserted through the holes 11c of the head part 11a. A vertical passage 55 is formed in the head part 11a, and a passage 56 formed from the upper end of the passage 55 through the hydraulic case 6 is communicated with the groove 36 side of the control valve 14. A passage 58 communicating with an intersection 57 provided at When the grip 60 on the front part is rotated, it can be operated from the screw fitting 61, and when the grip 60 is turned, the passage 5 is opened.
8 can be closed, but the passage 55 is configured to be open due to a gap 62 on the side of the stop valve 59.

In addition, the lower end of the passage 55 is closed by a plug 63, and a cross-shaped intersection 64 is provided in the passage 55 below the intersection 5γ. 71, and the IJ IJ-F valve R and plug body 71 are positioned opposite to the left and right side surfaces of the head 11a, and the relief valve R is operated by a compression spring 66 supported by a threaded body 65, as in the conventional structure. A passage 68 configured to support a steel ball 61 and communicating with the intersection 64 via the IJ-F valve R is communicated with the passage 53 below the control valve 14, and a passage 69 communicating with the intersection 64. A plug γ1 is detachably attached to the end by a screw 70 to close the end, but when the plug γ1 is removed, a pipe T2 is attached and the pipe 12 is connected to the hydraulic system 10 of the working machine 9. Configure it to do so.

Next, the effect will be explained.

When the rotary work lever 4 is raised or lowered by the hydraulic lift arm T without the work equipment 9 attached, the grip 60 is rotated to separate the stop valve 59 from the intersection 57 to open the valve 59 so as not to cause a so-called hydraulic lock. So, and
The end of the passage 69 is closed by the screw engagement γ0 of the stopper T1.

When raising the hydraulic lift arm 7, rotate the operating lever 1γ in the direction of arrow A and perform the raising operation. As the support shaft 16 rotates, the pin 18 on its outer circumference moves forward, and the upper end The lower end of the actuating lever 19, which is pulled by the tension spring 20, is moved forward, and the spool end that the lower front surface of the actuating lever 19 contacts is pushed in the retracting direction, and the spool B is moved by the compression spring 34. It moves in the retracting direction against the resistance, and enters the state shown in FIG.

Therefore, the land 42 of the spool B is connected to the groove 38.3 of the valve hole A.
9, the high pressure oil from the high pressure port 51 side does not flow to the passage 53 side, and the passage 4
8, the steel ball 4γ of the check valve C is pressed against the spring pressure, and the passages 49, 56, 55 and the intersection 51 are opened from inside the shaft hole 44.
, flows through the passage 58, flows into the hydraulic cylinder 11, hydraulically operates the piston 12, rotates the hydraulic lift arm 7 in the upward direction, and when the piston 12 reaches the bottom dead center side, the high-pressure oil flows backward. From the intersection 64, leaf valve R is actuated to flow from passage 68 to passage 53,54 and into the tank.

In that case, the end 28 of the rod 28 as shown in FIG.
1 is engaged with the hole 30 to perform position control, when the hydraulic lift arm 7 rises, the rod 28 receives a pulling action and the feedback lever 25 rotates the operating shaft 22. ,
At the same time, the shaft cylinder 23 and pin 24 rotate, and the pin 24 pushes the operating lever 19 forward, so that the lower part of the operating lever 19 rotates around the pin 18 and moves backward. However, the pressing force against the spool end recedes.

Therefore, the spool B pressed by the compression spring 34 moves within the valve hole A, and becomes in a neutral operating state in which the hydraulic lift arm 1 is stopped depending on the degree of rotation of the operating lever 11.

That is, in the neutral state, the control valve 14 is in the state shown in FIG. 3, and the high pressure oil from the high pressure port 51 flows into the 11 passage 53 from between the land 42 of the spool B and the land A4 of the valve hole A and is drained. The water flows from the passage 54 to the tank and does not flow to the hydraulic cylinder 11.

When the hydraulic lift arm 7 is brought down, the pin 18 is rotated by rotating the operating lever 17 in the direction of the opposite arrow A, and the spool B is moved to the neutral position as shown in FIG. Similarly to the state, the high pressure oil from the high pressure port 51 flows into the drain passage 54, and the oil in the hydraulic cylinder 11 moves in the direction in which the piston 12 drains the oil due to the weight of the work equipment that is loaded on the hydraulic lift arm 7. The oil in the cylinder 11 is pushed by pressure and flows back from the passage 58 through the intersection 57, the passages 55, 56, the grooves 36 and 37, and the valve 52, and from the passage 53 to the drain passage 54, and the arm is lowered. It will be done.

Position control is performed under such an operating state, but when performing depth control, if the end 28' of the rod 2B is switched to the hole 31 side and connected, the lowering of the hydraulic lift arm I causes the rotary to be aligned. When the work equipment 4 is on the ground and performing work, the wire 26 is pulled by the depth sensing operation of the sensor 5, or the pin 24 is moved back and forth by the tensioning action of the tension spring 20 in a slack state, and the pin 24 is moved to the operating lever 19. The hydraulic lift arm γ can be operated in the same manner as described above to control the neutral position or lifting/lowering operation of the hydraulic lift arm γ.

Further, in order to speed up or slow down the lowering operation of the hydraulic lift arm γ, the flow rate of the return oil from inside the hydraulic cylinder 11 can be adjusted by adjusting the rotation of the slow return valve 52.

Hydraulic lift arm γ without using rotary work equipment 4
If you want to lock it, hold the grip 60 and tighten the screw 61.
When the stop valve 59 is brought into contact with the intersection 57 and closed, the passage 58 is closed and a so-called hydraulic lock is performed.When the tractor is equipped with the work implement 9 and is hydraulically driven, the stopper 71 must be removed. pipe 7 at the end of passage 69
2 and the pipe 72 is connected to the hydraulic device 10, and the stop valve 59 is used to lock the hydraulic pressure, so that the high pressure oil from the control valve 14 side flows through the gap 62 within the passage 55. From intersection 64 to passage 6
9 and flows to the hydraulic system 10, and as a safety device, excess oil flows to the IJ-IJ-F valve R and is activated.

As described above, the present invention provides an agricultural tractor in which a lift arm 1 for raising and lowering a rear-mounted work implement 4 is driven by a hydraulic cylinder 11.
A head part 11a is fixedly installed in the front part of the hydraulic cylinder 11, and a passage 58 communicating with the top dead center side of the hydraulic cylinder 11 is provided in the head part 11a in a manner that crosses a passage 55 communicating with the control valve 14. The passage 55 is connected to the intersection 57 by a gap 62, and a stop valve 59 that can open and close only the passage 58 is provided in the intersection 57 so as to be freely advanced and retracted by operation from the front side of the head part 11a. On the other hand, the control valve 14 is inserted through the gap 62.
An IJ valve R and a plug body 71 provided in an intersection 64 facing the extended end of the passage 55 that communicates with the side are located opposite to the left and right side surfaces of the head portion 11a. Therefore, the relief valve R can function as a safety device both when communicating pressure oil to the hydraulic cylinder 11 and when communicating with the hydraulic system 10 of the working machine 9 by closing the stop valve 59. , and stop valve 59, relief valve R1 stopper T1, and various passages 55.5.
8.64 are arranged in a concentrated manner in the head section 11a, the various oil passages can be properly connected by simply assembling the head section 11a to the hydraulic cylinder 11 without requiring any special piping work. It can be assembled easily.

Furthermore, since the stop valve 59, the IJ valve R, and the plug body 71 are arranged on the front surface and both left and right side surfaces of the head part 11a, these operating members are distributed and located on the surface of the spatula 11a. Various effects can be achieved, such as making the operation easy and free from erroneous operations.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a side view of an agricultural tractor, Fig. 2 is an enlarged view of a part of it, Fig. 3 is a side sectional view of the main part, and Fig. 4 is a part of it. Front sectional view, Figure 5 is the 4th
6 is a side sectional view of a portion of the figure, FIG. 6 is a front sectional view of a portion of the control valve, and FIGS. 7 and 8 are explanatory views of the operation of the control valve. 4... Work equipment, 7... Lift arm,
11...Hydraulic cylinder, 14...Hydraulic control pal 7", 55, 58, 68...
-Passage, 11a...Head section, R-...Relief valve.

Claims (1)

[Scope of utility model registration request] In an agricultural tractor configured by driving a rear-mounted work implement 4 and a lift arm γ for raising and lowering it by a hydraulic cylinder 11, a head part 1 is provided at the front part of the hydraulic cylinder 11.
1a is fixedly installed, and in the head portion 11a, a passage 58 communicating with the top dead center side of the hydraulic cylinder 11 crosses a passage 55 communicating with the control valve 14, thereby forming an intersection 5γ. A stop valve 59 is provided at the intersection 57 so that the passage 55 is in communication with the gap 62, and a stop valve 59 that can open and close only the passage 58 is provided so as to be movable forward and backward by operation from the front side of the head portion 11a. A crossroad 64 facing the extended end of the passage 55 and communicating with the control valve 14 side in a cross shape.
The relief valve R and the stopper 11 provided inside the head part 1
A hydraulic system for an agricultural tractor, characterized in that it is configured to be located opposite the left and right sides of the tractor.