JPS5930646Y2 - Hydraulic control device for agricultural tractors - Google Patents

Description

[Detailed description of the invention] This invention relates to a hydraulic control system for agricultural tractors, and uses a control valve to control the lifting and lowering movement of a lift arm to control the second hydraulic drive system using an extremely simple hydraulic circuit. The object of the present invention is to provide a hydraulic control device for an agricultural tractor that can control the motion and simplify the operation of its second hydraulic drive device.

In this invention, a hydraulic passage connecting a first hydraulic drive device that drives a lift arm that raises and lowers a work machine and a control valve that controls this first hydraulic drive device is connected to a second hydraulic drive device. An external hydraulic pressure outlet is provided, and a valve for opening and closing the oil passage to the first hydraulic drive device is provided, and a ring body is rotatably arranged coaxially with the rotation center of the lift arm, and the ring an operating lever is connected to the body, a locking portion is formed that elastically engages and disengages the side surface of the lift arm and the ring body, and a spring is provided in the ring body to automatically return the ring body to a neutral position. The ring body and the operating section of the control valve are connected by a feedback link mechanism.

Therefore, when the lift arm is raised or lowered by operating the control valve, the movement of the lift arm is transmitted to the operating section of the control valve via the ring body and the feedback link mechanism to position the control valve in the neutral position. By closing the oil passage to the first hydraulic drive device and operating the operating lever, the second hydraulic drive device can be controlled using the control valve that controls the first hydraulic drive device. I can,
This makes it possible to perform other tasks with a simple hydraulic circuit without using a separate control valve; in this case, the ring body linked to the operating lever engages elastically with the locking part of the lift arm. Since the second hydraulic drive device is positioned at the neutral position, the second hydraulic drive device is configured to be easily controlled.

An embodiment of this invention will be explained based on the drawings.

Reference numeral 1 shown in FIG. 3 is a mission case provided in the body of the tractor.

A hydraulic case 2 is fixed to this mission case 1,
A first hydraulic drive device 3 is provided inside this as shown in FIGS. 1 and 4.

This first hydraulic drive device 3 includes a cylinder liner 4, a piston 5, a piston rod 6, and a cylinder head 7.

A hydraulic arm shaft 8 is supported on the hydraulic case 2, and a hydraulic arm 9 connected to the piston rod 6 is fitted and fixed in the center of the hydraulic arm shaft 8.

Further, a control valve 10 is provided on the right side of the hydraulic case 2.

As shown in FIG. 4, a hydraulic passage 11 is formed in the first hydraulic drive device 3 and is connected to the control valve 10 through a through hole 11a. check valve 12 that only allows flow to the hydraulic drive device 3;
and a flow control valve 13, which is a valve that opens and closes an oil passage between the first hydraulic drive device 3 and the control valve 10 in a manner that allows adjustment of the opening amount, and locks the first hydraulic drive device 3, is provided in parallel. It is being

This flow control valve 13 has a control knob 14 .

Further, an external hydraulic pressure outlet 16 is formed in the hydraulic passage 11 and is connected to the second hydraulic drive device 15 via a pipe 17.

Next, as shown in FIGS. 1 and 2, the lower end of the spool 18, which is the operating part of the control valve 10, is connected to the substantially lower middle part of an interlocking arm 19, and the upper end of this interlocking arm 19 has an outer end. It is connected by an interlocking link 22 to the inner end of a control lever shaft 21 fixed to a hydraulic control lever 20 shown in FIG.

Next, lift arms 2 are attached to both ends of the hydraulic arm shaft 8.
3 and 24 are spline-fitted, and the right lift arm 2
As shown in FIG. 5, a V-shaped space 25, which is a locking portion, is formed on the outside of 3. As shown in FIG.

V is a locking portion that removably engages with this V semi-concave portion 25.
A ring body 27 having an actual portion 26 is rotatably fitted to the hydraulic arm shaft 8 while being biased in a resiliently engaging direction by a spring 30, and the spring 30 is attached to a presser plate fixed by a bolt 28. 29 prevents removal.

This ring body 27 is connected to an operating lever 31 and is also interlocked with the spool 18 of the control valve 10 via a feedback link mechanism 32 and the interlocking arm 19.

The feedback link mechanism 32 includes a feedback lever 33 connected to the operating lever 31, a feedback lever shaft 34 that holds the feedback lever 33, and a feedback lever shaft 34 that is held at the other end of the feedback lever shaft 34 and connected to the interlocking arm 19. It consists of a connected interlocking plate 35.

In such a configuration, when the hydraulic control lever 20 is rotated in the direction of arrow C in FIG.
9 causes the spool 18 of the control valve 10 to slide in the direction of arrow C in FIG. 2, and oil is supplied into the cylinder liner 4 through the hydraulic passage 11.

That is, the first hydraulic drive device 3 is driven and the lift arms 23 and 24 are raised.

At this time, the ring body 27 that engages the lift arm 23 with the V-shaped part 25 and the V-shaped part 26 rotates in response, and the spool 18 returns to the neutral position by the operation of the feedback link mechanism 32 in conjunction with this. , the lift arms 23 and 24 are stopped at a fixed position.

When the hydraulic control lever 20 is turned in the direction of arrow C in FIG. 2, the lift arms 23 and 24 are lowered by an operation opposite to the above-mentioned operation, and the spool 18 returns to the neutral position due to the operation of the feedback link mechanism 32 at this time, and the lift arms 23 and 24 are lowered. 23 and 24 are stopped at a fixed position.

The above is the operation of the lift arm 23, 24 position control.

That is, by feeding back the operation of the lift arms 23 and 24 through the feedback link mechanism 32 and operating the spool 18 of the control valve 10, the lift arm 2 is moved to a position corresponding to the operating position of the hydraulic control lever 20.
3 and 24 are automatically stopped.

If the hydraulic control lever 20 is operated to raise the lift arms 23, 24 to the highest position and the flow rate control valve 13 is closed, the first hydraulic pressure 1 drive device 3 is locked and the lift arms 23, 24 are raised to the highest position. Hold in the raised position together with the work equipment.

Further, the control valve 10 and the second hydraulic drive device 15 are communicated with each other.

Then, when the operating lever 31 is operated, the ring body 27 moves against the force of the spring 30 and moves into the V-shaped space 25 as shown in No. 511b.
While releasing the engagement with the V fact part 26, it slides and rotates.

The feedback link mechanism 32 is interlocked with this, and the spool 18 is operated in accordance with the direction of rotation of the operating lever 31.
Therefore, oil is supplied to or recirculated to the second hydraulic drive device 15.

When the operating lever 31 is released, the V-shaped portion 25 and the V-shaped portion 26 are elastically engaged by the force of the spring 30, and the ring body 27 and the operating lever 31 are automatically returned to the neutral position. At this time, the control valve 10 is maintained in the neutral state by the operation of the feedback link mechanism 32.

In this way, since the second hydraulic drive device 15 can be controlled using the control valve 10 that controls the first hydraulic drive device 3 that drives the lift arms 23 and 24, the number of hydraulic circuit components can be reduced. The hydraulic circuit can be simplified.

In this case, the operation lever 31 automatically returns to the neutral position together with the ring body 27 due to engagement between the V semi-recessed portion 25 and the V-shaped portion 26, thereby simplifying the control operation of the second hydraulic drive device 15. Can be done.

Since this invention is configured as described above, it is possible to control the second hydraulic drive device using the control valve that controls the first hydraulic drive device without providing a separate control valve. The hydraulic circuit can be simplified, and the ring body and the operating lever automatically return to the neutral position due to the elastic engagement of the locking parts, and the control valve automatically returns to the neutral position through the interlocking operation of the feedback link mechanism. Therefore, the operation of the second hydraulic drive device can be simplified.

[Brief explanation of drawings]

The drawings show one embodiment of this invention; Fig. 1 is a vertical front view, Fig. 2 is a longitudinal left side view, Fig. 3 is a right side view, and Fig. 4 is a view taken along line X-X in Fig. 3. FIG. 5 is a partially cutaway, enlarged front view showing the operation of the ring body, and FIG. 6 is a longitudinal front view showing an enlarged state of attachment of the ring body. 3...First hydraulic drive device, 10...
Control valve, 11... Hydraulic passage, 13...
Flow rate control valve (valve), 15...Second hydraulic pressure, drive device, 16...External hydraulic pressure outlet, 18...
... Spool (operating part), 23-24 ... Lift arm, 25 ... V half-concave part (locking part), 26
...V fact part (locking part), 27...Ring body, 30...Spring, 32...Feedback link mechanism.

Claims (1)

[Scope of utility model registration request] An external hydraulic outlet to the second hydraulic drive device is provided in the hydraulic passage connecting the first hydraulic drive device that drives the lift arm that raises and lowers the work equipment and the control valve that controls the first hydraulic drive device. and a valve for opening and closing the oil passage to the first hydraulic drive device, a ring body rotatably disposed coaxially with the center of rotation of the lift arm, and a ring body rotatably mounted on the ring body. An operating lever is connected to form a locking portion that elastically engages and disengages the side surface of the lift arm and the ring body, and a spring is connected to the ring body that automatically returns the ring body to a neutral position. A hydraulic control device for an agricultural tractor, characterized in that the ring body and the operating section of the control valve are connected by a feedback link mechanism.