JPS5914483A - Hydraulic circuit for industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic circuit for preventing lightning motion during teaching in an industrial robot.

For example, there is a hydraulic circuit shown in FIG. 1 that enables automatic operation of a hydraulic industrial robot.

Briefly, hydraulic oil supplied from a hydraulic pump 1 via a check valve 2 is supplied to several electro-hydraulic servo valves 3 (one shown) which operate in response to signals from a separately provided electric control system. Each actuator 4 is controlled by an automatic switching valve.
This allows the main body of the industrial robot or its wrists to make desired movements.

In the hydraulic circuit of such an industrial robot, the required amount of hydraulic oil fluctuates because the robot operates intermittently. For this purpose, a hydraulic pump 1 and an electro-hydraulic servo valve 3 are used.
An accumulator 5 is installed in the pipe between the hydraulic pumps 1 and 1.
Efforts are being made to downsize the

By the way, during the teaching work of teaching the movement of an industrial robot prior to making it automatically operate, a worker often enters the work area of the industrial robot.

For this reason, means is used to limit in advance the current value acting on the electrohydraulic servo valve 3 so that the actuator for driving each axis operates slowly.

However, with only such deceleration means using signals from the electric control system, short circuit accidents may occur in the electric control system, or
When dirt adheres between the nozzle and flapper, reducing the nozzle opening area and causing problems such as an abnormal increase in biloft pressure, the opening of the electro-hydraulic servo valve increases, causing the robot to move at high speed. It may come into contact with workers in the work area and cause an unexpected accident.

In addition, when a situation arises in which the speed cannot be controlled by the electro-hydraulic servo valve as described above, even if the operator presses the full stop button and stops driving the hydraulic pump, the residual pressure in the accumulator causes the hydraulic fluid to drain. The drawback is that the actuator cannot be stopped immediately since it is still supplied to the electro-hydraulic servo valve.

The present invention has been made in order to solve the above-mentioned problems, and the first object of the present invention is to prevent short-circuit accidents that occur in the electrical control system during teaching, and Even if the electro-hydraulic servo valve becomes fully open due to the accumulation of garbage, etc., and the flow rate control by the servo valve becomes impossible, the actuator can continue to operate at a slow speed. Our goal is to provide hydraulic circuits for robots.

The second object of the present invention is to provide an industrial system in which the operation of each axis stops immediately when the operator performs an operation to stop the hydraulic pump when speed control using an electro-hydraulic servo valve becomes impossible. Our goal is to provide hydraulic circuits for robots.

The first aspect of the invention is characterized in that the hydraulic pressure of an industrial robot is equipped with an accumulator in the discharge pipe of a hydraulic pump, and the hydraulic fluid is guided to the actuator for driving each axis through an electro-hydraulic servo valve U7. In the circuit, a switching valve is installed in the supply line between the acuno, rake and the electro-hydraulic servo valve, and a branch line is connected in parallel to this supply line and has a flow control valve interposed in the middle. The second invention is characterized in that, in addition to the above configuration, the hydraulic fluid is guided to the electrohydraulic servo valve through this branch pipe when teaching. The downstream pipe line and the oil tank are connected by a pipe line equipped with an on-off valve, and this on-off valve operates in the closed position when the hydraulic pump is driven and in the open position when the hydraulic pump is stopped.

Hereinafter, the present invention will be explained in detail based on examples thereof.

FIG. 2 shows one embodiment of the present invention, in which the accumulator 5 and the electro-hydraulic servo valve 3 are switching valves, for example, a supply pipe 10 in which a two-position, two-boat type on-off valve 12 is disposed. It is connected to a branch pipe 11 which is provided in parallel with this pipe 1o and has a flow control valve 13 interposed therebetween.

The on-off valve I2 is in the closed position when the industrial robot is being taught and not in use, and is switched to the open position during automatic operation.

Further, the flow control valve 13 is adjusted so that a flow rate corresponding to the maximum speed of the actuator in a normal state during teaching can pass therethrough.

FIG. 3 shows another embodiment of the present invention, in which the accumulation rake 5 and the electro-hydraulic servo valve 3 are a switching valve, for example, a two-position, three-boat type directional switching valve 14. It is connected by a conduit 15 and a branch conduit 17 which is provided in parallel with the conduit 15 and has a flow control valve 16 interposed therebetween.

The directional switching valve 14 is in the A position when the industrial robot is being taught and not in use, and guides the hydraulic oil from the accumulator 5 to the electrohydraulic servo valve 3 via the branch pipe 17, and is switched to the B position during automatic operation. Change. In addition, the flow control valve 16
is adjusted so that a flow rate corresponding to the maximum speed of the actuator in the normal state at the time of teaching can pass through.

Since the present invention has the following circuit configuration, during teaching, the hydraulic fluid of the hydraulic pump 1 or the accumulator 5 flows through the branch pipe 11 with the flow control valve 13 or 16 interposed.
or 17 to the electrohydraulic servo valve 3.

As a result, an unexpected accident occurred in the electro-hydraulic servo valve 3.
Even if the opening becomes abnormally large, the maximum speed of the actuator at the time of teaching is regulated by the flow control valve 13 or 16, so it will not be high speed, and the operator will have to evacuate outside the robot's work area or the industrial This gives you time to perform an operation to stop the robot.

Next, FIGS. 4 and 5 show other embodiments of the invention, and the embodiment in FIG. 4 is on the downstream side of the flow rate control valve 13 in the hydraulic circuit of the embodiment shown in FIG. The pipeline and an oil tank (not shown) are connected via a pipeline 23 provided with an on-off valve 21 and a return pipeline 25. Also,
The embodiment shown in FIG. 5 is the hydraulic circuit of the embodiment shown in FIG. They are connected via a side pipe 25. On-off valves 21 and 2
2 is in the closed position when the hydraulic pump 1 is driving, and is not switched to the open position when the hydraulic pump 1 is stopped.

With the above configuration, when driving an industrial robot, the on-off valve 21 or 2 is activated at the same time as the hydraulic pump is started.
2 switches to the closed position and cuts off communication with the oil tank, so the oil pressure in the supply path increases and hydraulic oil is accumulated in the accumulator 5.

When performing the teaching operation, as described above, the branch pipe 11.
Hydraulic oil is guided to the actuator 4 through the electro-hydraulic servo valve 3 and the electro-hydraulic servo valve 3. Even if an unexpected accident occurs in the electro-hydraulic servo valve 3 and flow control becomes impossible, the actuator The speed is controlled by the flow control valve 13 or 1.
6, so the low speed state is maintained.

Further, when the operator notices an abnormality and stops the hydraulic pump 1, the on-off valve 21 or 22 is activated to the open position at the same time, so that the hydraulic fluid accumulated in the accumulator is transferred to the branch pipe 11 or 17 and the flow control valve 13. Or 16, the oil is returned to the oil tank via the pipe 23 or 24, the on-off valve 21 or 22, and the return pipe 25. Therefore, the actuator can be stopped immediately.

Furthermore, when the on-off valve 21 or 22 is switched to the open position, the hydraulic oil accumulated in the accumulator is returned to the oil tank via the flow control valve 13 or 16, so the pressure drop in the accumulator is gradually reduced. This can prevent the occurrence of impact.

As described in detail above, the present invention provides a hydraulic circuit for an industrial robot that includes an accumulator in the discharge pipe of a hydraulic pump and guides hydraulic fluid to an actuator for driving each axis via an electro-hydraulic servo valve. In the teaching method, a switching valve is provided in the supply line between the accumulator and the electro-hydraulic servo valve, and a branch line is connected in parallel to this supply line and has a flow control valve interposed in the middle. In some cases, the hydraulic fluid is guided to the electro-hydraulic servo valve through this branch line, so even if an accident occurs in the electric control system during teaching or the electro-hydraulic servo valve is unable to adjust the flow rate, the actuator will continue to operate. The robot can still operate at a slow speed, and dangerous robot movements such as the robot body or arm colliding with the worker being taught at high speed can be prevented.

Furthermore, in addition to the configuration of the invention described above, a pipe line is provided for returning the hydraulic fluid from the switching valve and the flow control valve to the hydraulic tank via the on-off valve, so the actuator can be stopped immediately, and the robot body and arm This has the effect of preventing the worker from colliding with the worker being taught.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram of a conventional industrial robot, Figs. 2 and 3 are main part diagrams of a hydraulic circuit of an industrial robot of the present invention, and Figs. 4 and 5 are diagrams of a hydraulic circuit of a conventional industrial robot. A diagram of the main parts of the robot's hydraulic circuit, 1-hydraulic pump, 3-electro-hydraulic servo valve, 5-accumulator, 10.15-.
- Supply pipeline, 12.14 - Switching valve, 13.16 - Flow rate control valve, 11.17 - Branch pipeline, 21.22 - Opening/closing valve, 2
3.24-Pipe patent applicant Kawasaki Heavy Industries Co., Ltd. Agent Patent attorney Katsutoshi Yoshimura ←-H← Figure 2 Figure 3 Figure 4 Figure 5

Claims (6)

[Claims] (1) In the hydraulic circuit of an industrial robot, which is equipped with an accumulator in the discharge line of the hydraulic pump and guides hydraulic fluid to the actuator for driving each axis via an electro-hydraulic servo valve, the accumulator and the electro-hydraulic servo A switching valve is provided in the supply line between the valve and the supply line, and a branch line connected in parallel to this supply line with a flow rate control valve interposed in the middle is provided, and during teaching, the flow rate is controlled through this branch line. A hydraulic circuit for an industrial robot, characterized in that an operating axis is guided to an electro-hydraulic servo valve. (2) A hydraulic circuit for a marine industrial robot according to claim 1, wherein the switching valve is an on-off valve, and the on-off valve is arranged in parallel with the flow rate control valve. (3) The switching valve is a directional switching valve, and includes a pipe line that directly leads hydraulic oil to the electrohydraulic servo valve and a pipe line that supplies hydraulic oil whose flow rate has been adjusted via the flow rate control valve. The hydraulic circuit for an industrial robot according to claim 1, wherein the hydraulic circuit is connected to an outlet of the directional control valve. (4) In the hydraulic circuit of the industrial robot 1-, which is equipped with an accumulator in the discharge pipe of the hydraulic pump and guides hydraulic oil to the actuator for driving each axis via an electro-hydraulic servo valve, the accumulator and the electro-hydraulic A switching valve is provided in the supply line between the type servo valve and a branch line connected in parallel to this supply line with a flow control valve interposed in the middle, and a branch line is provided downstream of the flow rate control valve. The side pipe and the oil tank are connected by a pipe equipped with an on-off valve, and during teaching, hydraulic oil is guided to the electro-hydraulic servo valve through this branch pipe, and when the hydraulic pump is driven, the on-off valve is connected. A hydraulic circuit for an industrial spout pot, characterized in that it operates in a closed position and in an open position when stopped. (5) The hydraulic circuit for an industrial robot according to claim 4, wherein the switching valve is an on-off valve, and the on-off valve is arranged in parallel with the flow rate side valve. (6) The switching valve is an on-off valve, and includes a pipe line that directly leads hydraulic oil to the electrohydraulic servo valve and a pipe line that supplies hydraulic oil whose flow rate has been adjusted through the flow rate control valve. 5. The hydraulic circuit for an industrial robot according to claim 4, wherein the hydraulic circuit is connected to an outlet of the directional control valve.