JPH04360919A - Oil-pressure operation lever - Google Patents

Abstract

PURPOSE:To raise the operability and safety of an oil-pressure operation lever by a method in which an oil path through which oil is set to actuators is branched and connected to a cylinder in order to supply a pressure oil according to loads. CONSTITUTION:An angle sensor 11 provided on the rotary base of an operation lever 10 is connected to a control circuit 12, and a support lever 13 is also provided in the turning direction for the lever 10. The lever 13 is contacted with springs 14a and 14b and then with piston rods 15a and 16a, The control circuit 12 is connected to the solenoids 17a and 17b of a control valve 17, and the port A is connected with the rod side of the oil-pressure cylinder 20 of the actuator. At the same time, the port B is connected with the head side, and the ports A and B are connected to the cylinders 15 and 16 through throttles 21 and 22. By turning the lever 10 toward the ascending side and the descending side, pressure oil is sent through the solenoids 17b and 17a from the control circuit 12 to the cylinder 20. The reaction of the lever 10 can be increased.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an operating lever used to operate an actuator of a hydraulic working machine of a construction machine or a traveling vehicle.

0002

[Prior Art] In recent years, electric joystick-type operating levers have come into use, which allow easy connection between the operating lever and the switching valve using only wiring, without using an arm or link. . For example, in the case of a backhoe, the control lever for operating the boom, bucket, etc. is provided with an angle sensor 2 at the center of rotation of the control lever 1, as shown in FIG. A spring 6 is provided at the base of the control lever to return it to the neutral position, and when the control lever is rotated, a signal of the rotation angle is sent to the control circuit 3, which outputs a value proportional to the rotation angle. is sent to the solenoid 4a or 4b of the switching control valve 4 and switched, and the hydraulic cylinder 5, which is the actuator, is extended or contracted.

0003

[Problem to be Solved by the Invention] However, since the operating lever is returned to the neutral position by the springs 6 and 6 and is not connected to the actuator, it rotates regardless of the load on the work equipment. , there is no reaction force against the load, the operation feeling is poor, the work equipment is damaged by working with an overload, and the temperature of the hydraulic oil increases as the oil is sent from the relief valve 7 to the tank side.
Additionally, if you let go of the control lever from the full throttle position, the control lever will rotate beyond the neutral position to the opposite side, causing the work equipment to move in the opposite direction and cause hunting, which will cause the operator to move in ways that are unexpected and create a very dangerous situation. It may happen. And because it was easy to operate, it didn't feel heavy and felt cheap.

0004

[Means for Solving the Problems] In order to solve these problems, the present invention has a structure in which a hydraulic operating lever is held in a neutral position by a spring, and the piston rods of the cylinder are brought into contact with the support rods. The actuator is in contact with the actuator, and is connected to the cylinder by branching from an oil path that sends oil to the actuator, so that pressure oil corresponding to the load can be sent.

Another method is to protrude support rods on each side in the rotational direction of the operating lever, urge the support rods in the neutral direction with springs, and connect the respective springs to the spool of the switching valve. Then, a cylinder is provided on the opposite side of the spool via a spring, and the cylinder is branched from the oil line on the pump port side that sends oil to the control valve and connected via a relief valve and a pressure reducer. It is configured to send pressurized oil.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problems to be solved by the present invention and the means for solving them are as described above.Next, the structure of an embodiment in which the working machine shown in the attached drawings is a backhoe boom will be explained. FIG. 1 is a hydraulic circuit diagram showing a first embodiment. An angle sensor 11 is disposed at the rotation base of the operating lever 10, and the angle sensor 11 is connected to a control circuit 12.
The operation lever 10 has a support rod 13 in the rotation direction (horizontal).
are provided in a protruding manner, and springs 14a and 14b are brought into contact with the rotation direction sides of the support rods 13 to urge them upward, and are also brought into contact with the tips of piston rods 15a and 16a of the cylinders 15 and 16.

The control circuit 12 is connected to solenoids 17a and 17b of an electromagnetic proportional control valve 17, and the control valve 17 switches the discharge direction of pressure oil from the hydraulic pump. A is connected to the rod side of a hydraulic cylinder 20 which is an actuator for vertically rotating the boom 19, and port B of the control valve 17 is connected to the head side of the hydraulic cylinder 20.

Port A is connected to the cylinder 15 through a throttle 21, and port B is connected to the cylinder 16 through a throttle 22. However, although an operating lever, an angle sensor, an electromagnetic proportional switching valve, etc. are connected to each of the hydraulic cylinders that rotate the bucket, swing arm, etc., they are not shown in this embodiment.

With this configuration, when the operating lever 10 is rotated in the upward direction, the signal from the angle sensor 11 turns on the solenoid 17b via the control circuit 12 and is transmitted from port B to the head side of the hydraulic cylinder 20. The hydraulic cylinder 20 is extended by sending pressure oil. As the cylinder 16 expands, the pressure fed to the cylinder 16 via the throttle 22 increases, and the reaction force that returns the operating lever 10 to the neutral side increases, allowing the operator to feel the load. At this point, if the control lever 10 is returned to neutral or released, it will return to neutral due to the biasing force of the spring 14b, but the hydraulic oil in the cylinder 15 will be returned to the tank via the throttle 21. The cylinder 15 acts as a damper and recoil is kept to a minimum without exceeding the neutral position.

Conversely, when the operating lever 10 is rotated in the downward direction, the solenoid 17a is turned on, pressure oil is sent from port A to the rod side of the hydraulic cylinder 20, and the boom 19 is lowered, as described above. As the hydraulic cylinder 20 contracts, the reaction force that returns the operating lever 10 to the neutral side increases. Further, in the hydraulic circuit configuration of the second embodiment shown in FIG. 2, a support rod 31 is protruded from the operating lever 30 in the rotation direction, and the support rod 31 is biased from below both ends by springs 32a and 32b. The springs 32a and 32b
is in contact with one end of the spool of the switching valves 33 and 34,
The other end is connected to the cylinder 35 via springs 46 and 47, respectively.
・It is in contact with the piston rod of 36.

The switching valves 33 and 34 are valves for switching the control valve 39, and the spool of the control valve 39 is slid by pilot oil passages 44 and 45. Output side port A・
B is connected to, for example, a hydraulic cylinder 37 that rotates the boom. A hydraulic pump 25 driven by an engine 24 is connected to the pump port. Further, a hydraulic pump 26 is connected to the engine 24 and connected to pump ports of the switching valves 33 and 34.

A closed circuit consisting of a low-pressure relief valve 40, a single-acting pressure reducer 41, and a continuous pressure reducer 42 is connected to a closed circuit branching from the oil passage between the hydraulic pump 25 and the pump port. The relief valve 43 is also arranged in a branched manner to prevent overload. Then, it branches from between the pressure reducer 41 and the pressure reducer 42 and is connected to the cylinders 35 and 36, and between the piston rod tips of the cylinders 35 and 36 and the spools of the switching valves 33 and 34, springs 46 and 46 are connected.
47 is interposed.

With this configuration, when the operating lever 30 is rotated to the upward side, the support rod 31 is tilted and the switching valve 34 is switched so that the pressure oil from the hydraulic pump 26 is controlled via the pilot oil passage 45. The valve 39 is switched to send pressure oil from the hydraulic pump 25 to the hydraulic cylinder 37. As it extends, the pressure inside the hydraulic cylinder 37 increases and the relief valve 40 opens, allowing low-pressure oil to flow into the cylinder 37 via the pressure reducer 41.
As a result, the reaction force that returns the operating lever 30 to the neutral side increases. Conversely, when the operating lever 30 is rotated to the lowering side, the support rod 31 is tilted and the switching valve 34 is switched, and the pressure oil from the hydraulic pump 26 passes through the pilot oil path 44 and switches the control valve 39 to the hydraulic cylinder. Hydraulic pump 25 to the piston rod side of 37
When the pressure increases, low-pressure oil is sent to the cylinder 3 via the relief valve 40 and pressure reducer 41.
5, the reaction force of the operating lever 30 increases.

[0014]

[Effects of the Invention] With the above structure, when the operating lever is rotated to operate the actuator, the reaction force of the operating lever increases as the pressure increases, and the operator can manually check the load condition. As a result, workers no longer have to do unreasonable work, and there is less chance of damaging the work equipment. Furthermore, since the operation of the relief valve can be confirmed via the operating lever, the relief time is shortened and the rise in oil temperature is relatively small. Also, since there is a cylinder on the opposite side of the operating lever, this cylinder acts as a damper, so that even if you let go of the operating lever, it will not move over and perform the opposite operation. This means that there is no more hunting, and no more unexpected accidents.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a conventional hydraulic circuit diagram.

[Explanation of symbols]

10/30 Operation lever 13/31 Support rod 14/32/46/47 Spring 15/16/35/36 Cylinder 17/39
Control valves 20, 37 Hydraulic cylinders 33, 34 Switching valve 40 Relief valves 41, 42 Pressure reducer

Claims (2)

[Claims] Claim 1: In a structure in which a hydraulic operating lever is held in a neutral position by a spring, the piston rods of the cylinders are brought into contact with the support rods, and the cylinders are connected to branch from an oil path that supplies oil to the actuator. A hydraulic operating lever characterized in that it is configured to feed pressure oil according to the load. 2. In a structure in which the hydraulic operating lever is held in a neutral position by a spring, the spring in each rotation direction is connected to a spool of a switching valve, and a cylinder is provided on the opposite side of the spool via a spring, A hydraulic operation characterized in that the cylinder is branched from an oil path on the pump port side that sends oil to the control valve and is connected via a relief valve and a pressure reducer to feed pressurized oil according to the load. lever.