JPS60179502A - Operating circuit for hydraulic actuator - Google Patents

Abstract

PURPOSE:To enhance maneuverability as well as safety by furnishing a solenoid valve in parallel with a manually operated pilot valve, and by coupling them to the pilot operating part of a hydraulic pilot direction control valve through a shuttle valve. CONSTITUTION:A manually operated pilot valve 6 and a solenoid valve 9 are installed parallelly and coupled to the pilot operating part of a hydraulic pilot direction control valve 4 through a shuttle valve 10. This enables introduction of the higher one of these operating pressures to said hydraulic pilot direction control valve 4, so that complex operation in linkage with other operating circuits can be accomplished relatively easily, ensuring enhancement of the maneuverability. Also drive control of the hydraulic actuator can be carried through even in the event of any failure in the manually operated pilot valve part 6, so that the safety may be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an operating circuit for a hydraulic actuator provided in a hydraulic machine such as a crane.

[Background of the invention]

FIG. 1 is a circuit diagram showing an example of a conventional hydraulic actuator operating circuit, and this operating circuit is provided in, for example, a crane. In the figure, 1 is a prime mover, 2 and 3 are a main pump and an auxiliary pump driven by this prime mover 1, 4 is a hydraulic pilot directional control valve that controls the supply direction of the pressure oil supplied from the main pump 2, and 5 is a hydraulic pilot direction control valve. A hydraulic actuator connected to the directional control valve 4 and driven by pressure oil supplied from the main pump 2 is, for example, a motor that winds up and lowers a wire. Further, 6 is a manually operated pilot valve that is connected to the auxiliary pump 3 and generates operating pressure to drive the directional control valve 4, and 7 is this manually operated pilot valve 6.
A manually operated lever 8 is a tank in which hydraulic oil is stored.

In the operation circuit configured in this way, the prime mover 1
When the pilot valve 6 is actuated by the manual operation lever 7 while the main pump 2 and the auxiliary pump 3 are driven, the pressure oil of the auxiliary pump 3 is guided to the directional control valve 4 as operating pressure via the pilot valve 6. As a result, the directional control valve 4 is switched from the neutral position shown in FIG. 1 to the right or left position. Pressure oil from the main pump 2 is supplied to the motor 5 via the directional control valve 4, which rotates the motor 5 to perform winding and lowering operations of the wire (not shown).

By the way, such lanes are generally equipped with a boom capable of raising and lowering, and the above-mentioned wire equipped with a hook at the tip for hoisting articles is attached to this boom. The operating circuit of the hydraulic actuator that drives this boom is also constructed almost the same as that shown in FIG. 1 described above. That is, the motor 5 in FIG.
is the motor of the winch drum that raises and raises the boom, and is the operating circuit for operating the motor.

In order to efficiently lift and lower objects, cranes equipped with such operation circuits have the following functions:
It is often necessary to simultaneously drive the motor 5 shown in FIG. 1 and, for example, the motor that drives the above-mentioned boom. It is necessary to simultaneously operate both manual operation levers (not shown) for driving the motor, which requires advanced operating techniques.

In addition, in the conventional operation circuit shown in FIG. 1 described above, if the pilot valve 6 part fails, the drive control of the motor 5 becomes impossible, and such a failure occurs especially during lifting and lowering work of articles. If this occurs, there is a risk of accidents such as objects falling, which is a safety problem.

[Purpose of the invention]

The present invention has been developed in view of the actual situation in the prior art, and its purpose is to relatively easily realize combined operation with other operation circuits, and to reduce the number of manual operation pilot valve parts. An object of the present invention is to provide an operating circuit for a hydraulic actuator that can perform drive control of the hydraulic actuator even when a failure occurs in the hydraulic actuator.

[Summary of the invention]

In order to achieve this object, the present invention provides an electromagnetic pulp in parallel with a manually operated pilot valve that operates a hydraulic pilot directional control valve that controls the drive of a hydraulic actuator, and also combines the operating pressure of the manually operated pilot valve with the electromagnetic pulp. A shuttle pulp is provided to select a high pressure from among the operating pressures and guide it to the hydraulic pilot directional control valve, and the hydraulic pilot directional control valve is selectively operated either manually or automatically.

[Embodiments of the invention]

Hereinafter, the operation circuit of the hydraulic actuator of the present invention will be explained based on the drawings. Fig. 2 is a circuit diagram showing an embodiment of the present invention, which corresponds to the operating circuit provided in the crane shown in Fig. 1, and the same components as those shown at the end of Fig. 1 described above are designated by the same reference numerals. be.

In the m2 diagram, reference numeral 9 denotes an electromagnetic pulp, which is provided in parallel with the manually operated pilot valve 6 and connected to the auxiliary pump 3 and tank 8. This electromagnetic pulp 9 is configured to operate variably depending on the magnitude of an external signal, for example, by a signal from an electric circuit (not shown). A shuttle valve 10 is interposed between the pilot valve 6 and the electromagnetic pulp 9, and the directional control valve 4, and is used to transfer the higher pressure of the operating pressure of the pilot valve 6 and the operating pressure of the electromagnetic nozzle 9. selected and guided to the directional control valve 4. The other configurations are the same as those shown in FIG. Although not shown, other operating circuits included in the crane equipped with this embodiment, such as an operating circuit for a hydraulic actuator that drives the boom, are also configured as shown in FIG.

In the operation circuit configured in this way, the prime mover l
When the pilot valve 6 is actuated by the manual operation lever 7 while the main pump 2 and the auxiliary pump 3 are driven, the pressure oil of the auxiliary pump 3 is passed through the pilot valve 6 and the shuttle pulp 10 to the directional control valve as operating pressure. 4, thereby switching the directional control valve 4 from the neutral position shown in FIG. 2 to the right or left position. Pressure oil from the main pump 2 is supplied to the motor 5 via the directional control valve 4, which rotates the motor 5 to perform winding and lowering operations of the wire (not shown).

Furthermore, when the main pump 2 and the auxiliary pump 3 are driven by the prime mover 1, and the manual operation lever 7 is not operated, the electromagnetic pulp 9 is variably operated according to the magnitude of an external signal (not shown). The pressure oil of the auxiliary pump 3 is guided to the directional control valve 4 as operating pressure via the electromagnetic pulp 9 and the shuttle pulp 10, and thereby the directional control valve 4
It can be switched from the neutral position shown in the figure to the right or left position. Pressure oil from the main pump 2 is supplied to the motor 5 via the directional control valve 4, which rotates the motor 5 to perform winding and lowering operations of the wire (not shown).

In one embodiment configured in this way, the directional control valve 4 is manually operated by a manual operation lever 7, and the electromagnetic pulp 9
Therefore, if some kind of failure occurs in the pilot valve 6 part during manual operation, the electromagnetic pulp 9 can be immediately driven by an external signal to switch to automatic operation. On the other hand, when some kind of failure occurs in the electromagnetic pulp 9 part during automatic operation, f can immediately drive the pilot valve 6 with the manual operation lever 7 to shift to manual operation, and continue controlling the drive of the motor 5. Therefore, there is no interruption in the work of lifting and lowering articles. therefore,
Even in such a case, it is possible to prevent a decrease in work efficiency and also to prevent accidents such as falling objects. .

In addition, in an embodiment configured as described above and a crane equipped with an operation circuit for a hydraulic actuator for boom elevation (not shown) configured equivalently to this embodiment, the hydraulic actuator and the second When simultaneously driving the motor 5 shown in the figure 1c, for example, the hydraulic actuator can be driven by a manual operation lever (not shown), and the motor 5 shown in FIG. 2 can be driven by operating the electromagnetic pulp 9 by an external signal. Therefore, the operating technique is relatively simple because it is not necessary to operate both manual operating levers simultaneously.

Further, in one embodiment configured as shown in FIG. 2, an electric pulp 9 is added to the conventional operation circuit illustrated in FIG.
and Shuttle Pulp 10. The structure is simple, requiring only the addition of additional piping and related piping, and therefore the manufacturing cost is minimal.

In addition, in the above embodiment, the operation circuit provided in a clay truck was mentioned, but the present invention is not limited to such a device provided in a lane, but can be applied to various hydraulic machines such as a hydraulic excavator. It is.

〔Effect of the invention〕

As described above, the hydraulic actuator operating circuit of the present invention provides an electromagnetic pulp in parallel with the manually operated pilot valve, and applies one of these operating pressures to the directional control valve that controls the hydraulic actuator via the shuttle valve. Since it is designed to be guided, it is possible to relatively easily realize a combined operation with other operation circuits, which has the effect of improving operability compared to the conventional one. In addition, even if a failure occurs in the manually operated pilot valve part, the drive control of the hydraulic actuator can be performed. In other words, it is possible to appropriately select between manual drive control of the hydraulic actuator and automatic control of the hydraulic actuator. This has the effect of improving workability and safety compared to. Moreover, electrical control by a microcomputer is also possible, and more advanced automatic control can be performed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a conventional hydraulic actuator operating circuit, and FIG. 2 is a circuit diagram showing an embodiment of the hydraulic actuator operating circuit of the present invention. 2...Main pump, 3...Auxiliary pump,
4...Hydraulic pilot directional control valve, 5...
...Motor (hydraulic actuator), 6...Manual operation pilot valve, 7...Manual operation lever,
9... Electromagnetic pulp, 10... Shuttle pulp.

Claims (1)

[Claims] A hydraulic actuator, a hydraulic pump that supplies pressure oil to the hydraulic actuator, a hydraulic pilot direction control valve that controls the supply direction of the pressure oil supplied from the hydraulic pump to the hydraulic actuator, and the hydraulic pilot direction control valve. In an operating circuit for a hydraulic actuator having a manually operated pilot valve to be driven, a solenoid valve is provided in parallel with the manually operated pilot valve, and a higher pressure is selected between the operating pressure of the manually operated pilot valve and the operating pressure of the solenoid valve. An operating circuit for a hydraulic actuator, characterized in that a shuttle valve is provided for guiding the hydraulic pilot direction control valve to the hydraulic pilot direction control valve.