JPH0622602U - Pilot pressure generation mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] Internal pilot of an electromagnetic multi-directional directional control valve that uses a solenoid valve or the like to switch the control spool of a multi-directional directional control valve that has an unload line used for truck cranes, aerial work vehicles, etc. Aim to save energy, reduce dust, and downsize the pressure generation mechanism. [Structure] A spool 5a of a sequence valve 5 for securing pilot pressure oil to be supplied to solenoid valves 23a, 23b of an electromagnetic multi-directional switching valve 2 provided with a supply / discharge block 1 at one end.
To the pressure oil inflow port 10 for supplying the pressure oil 9 from the pump to
And a high pressure side 13a of the relief valve 13 to communicate with each other, a pressure oil inflow passage 15 is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention is an internal pilot pressure generation mechanism for an electromagnetic multi-directional directional control valve that uses a solenoid valve to switch the main spool of a multi-directional directional control valve that has an unloading line used for truck cranes, aerial work vehicles, etc. Regarding improvement.

[0002]

[Prior art]

 Conventionally, a hydraulic circuit configuration of an electromagnetic multi-directional directional control valve (hereinafter referred to as an electromagnetic multi-valve) in which a main spool of this type of directional control valve can be controlled by a solenoid valve or the like has been disclosed in Japanese Utility Model Laid-Open No. 64-27506. It is described in FIG. (B) and FIGS. 2 and 3 of Japanese Utility Model Laid-Open No. 58-176883. As shown in FIG. 3, these electromagnetic multi-valves are composed of a supply / discharge block 1b, a directional switching valve 2 having an unload line 24 for switching the main spool 21 with an electromagnetic valve, and a tank plate 3, Alternatively, a plurality of directional control valves 2a, 2b are sandwiched between a supply / discharge block and a tank plate and assembled together.

The directional control valve 2 includes a main spool 21 for distributing pressure oil to an actuator such as a hydraulic cylinder (not shown), and a small actuator integral with the main spool or mechanically coupled to the main spool, for example, a small cylinder. 22 and a solenoid valve section 23 that controls the main spool 21 by supplying pressure oil to a small cylinder. In addition, the directional control valve 2 supplies an unload line 24 as an oil passage for supplying pressure oil to the main spool 21, and a control pilot pressure oil having a pressure lower than the main pressure to the solenoid valve portion 23 and the small cylinder 22. A pilot line 1 1 is provided. As the solenoid valves 23a and 23b provided in the solenoid valve unit 23, proportional pressure reducing valves, high-speed ON-OFF valves, etc. are used, and the solenoid valve unit can be operated by remote control to operate the small cylinder 22 to operate the main spool 21. Is being done. By operating the main spool 21 remotely or manually, actuators such as hydraulic cylinders and hydraulic motors connected to the switching valves 2 can be operated.

The supply / discharge block 1b is adapted to supply the pressure oil 9 from the pump and the pilot pressure oil for control to the direction switching valve 2 and return the return oil from the direction switching valve to the tank. A pressure oil inflow port 10 that receives the pressure oil 9, a relief valve 13 that controls the maximum pressure of the hydraulic circuit, an unload solenoid valve 14 that is provided in the relief valve vent circuit 14a, and the pressure of the pilot line of the solenoid valve section are controlled. The pressure reducing valve 12 and the pilot line 11a, the sequence valve 5b for securing the pilot pressure, and the pressure oil inflow port 10 are the unload line 24a for supplying pressure oil to the direction switching valve 2 via the sequence valve 5b and the pilot line. A filter (not shown) is provided to prevent malfunction due to dust. The unload solenoid valve 14 puts the relief valve 13 into an unload state when it is not necessary to stop the actuator or operate the directional control valve in an emergency.

The tank plate 3 is attached to the end portion thereof, and serves as a lid of the directional control valve 2b at the outermost end, and a communication passage 3a connecting the unload line 24 of the directional control valve and the tank line 17 is provided. It is provided.

By the way, since the electromagnetic multi-valve is mounted on a vehicle such as a truck crane and an aerial work vehicle as described above, downsizing is required. Therefore, the relief valve 13 and the solenoid valve that form a hydraulic circuit are required. Elements such as 14, the pressure reducing valve 12, the sequence valve 5b, and the filter must be built in or assembled in the supply / discharge block 1b in a smaller and compact size. Therefore, when designing the supply / discharge block, we examined the size of each part, etc., and found that the pilot line had a small control flow rate and the pressure was low, so the pilot line bore was small and the pressure reducing valve and filter were also small. It was possible to make it relatively compact. On the other hand, since the pressure oil inflow port 10, the relief valve 13, and the sequence valve 5b have a large passing flow rate and a high pressure, the size of each part becomes large, which is an important factor for determining the size of the supply / discharge block.

On the other hand, conventionally, two types of circuit configurations related to the sequence valve and the relief valve have been generally used as shown in FIGS. 2 and 3. In the circuit configuration according to FIG. 3, the sequence valve 5b is provided in front of the relief valve 13 for the hydraulic oil inflow port 10 to take out pilot pressure. According to this method, the pressure oil inflow port, the sequence valve, and the high pressure side of the relief valve can be arranged in series, so that the supply / discharge block 1b can be made compact. However, since the pilot pressure is constantly generated by the sequence valve 5b even when the relief valve is unloaded when the electromagnetic multi-valve is not used, there has been a problem that hydraulic oil is deteriorated due to heat generation and energy loss is large.

Therefore, in the circuit configuration according to FIG. 2, by arranging the sequence valve 5b and the relief valve 13 in parallel to the pressure oil inflow port 10, the direct pressure oil inflow port can be directly connected without going through the sequence valve. The pressure control was performed by the relief valve 13. Therefore, since the pilot pressure by the sequence valve 5b is not generated when the relief valve is unloaded, deterioration of hydraulic oil due to heat generation and energy loss can be reduced, and the above problem can be solved. .

[0009]

[Problems to be solved by the device]

 However, in the case of the circuit configuration according to FIG. 2, since the sequence valve 5b and the relief valve 13 need to be arranged in parallel with the pressure oil inflow port 10, the pressure oil from the pressure oil inflow port to the high pressure side of the relief valve 13 is pressed. There is a drawback that the supply / discharge block 1a becomes large due to the need for a new pressure oil inflow path for introducing the oil. Also, the unloading time is often quite long, and during that time the hydraulic oil flows directly into the relief valve 13 and does not pass through the sequence valve 5b, so the oil accumulates in the sequence valve section and a dust accumulation section 5d is generated, causing the operation. There was a problem that defects were likely to occur.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to unload a relief valve without increasing the size of the supply / discharge block. In the meantime, there is no need to generate pilot pressure due to the sequence valve, heat generation and energy loss can be reduced, and an electromagnetic multi-valve that is also resistant to dust is to be provided.

[0011]

[Means for Solving the Problems]

 Referring to FIG. 1 showing an embodiment, in order to achieve the above object, in the present invention, pressure oil is applied to a spool 5a of a sequence valve 5 provided in a supply / discharge block 1 constituting a supply / discharge unit. The above-mentioned problems have been solved by providing a pilot pressure generating mechanism characterized in that a pressure oil inflow passage 15 is formed that connects the inflow port 10 and the high pressure side 13a of the relief valve 13.

[0012]

[Action]

 According to the above configuration, the pressure oil 9 supplied from the pump to the pressure oil inflow port 10 of the supply / discharge block 1 is applied to the spool 5a of the sequence valve 5 to open the spool of the sequence valve. The pressure oil passes through the pressure oil inflow passage 15 provided in the spool 5a of the sequence valve 5 without forming a stagnant portion of the oil flow on the primary pressure side 5e of the sequence valve 5, and always maintains the high pressure side of the relief valve 13. 13a.

When the relief valve 13 is unloaded, the spool 5a of the sequence valve 5 remains closed and no pressure oil is supplied to the secondary pressure side 1d of the sequence valve. When the relief valve 13 is on-loaded, the spool 5a of the sequence valve 5 operates at the set pressure as the pressure increases, and the pilot pressure is secured. On the other hand, the pressure oil 9 is supplied from the pressure oil inflow port 10 to the unload lines 24a, 24 through the primary pressure side 5e of the sequence valve 5 and the secondary pressure side 1d.

[0014]

【Example】

 One embodiment of the present invention is shown in FIG. In FIG. 1, a collar 5c of a spool 5a abuts a shoulder portion 4a of a stepped hole 4 provided in a supply / discharge block 1, and is slidably inserted. The other end of the collar 5c is in contact with the spring 6, and the spring 6 is installed with a prescribed load applied by the plug 7. The plug 7 is fixed to the supply / discharge block 1 by screws 7a and is sealed by an O-ring 8 to prevent external leakage. The spring chamber 1c of the supply / discharge block 1 communicates with a tank line 17 via a drain line 16 in the supply / discharge block. A pressure oil inflow port 10 for supplying pressure oil 9 from the pump is provided coaxially with the spool 5a in the supply / discharge block 1, and the pressure oil 9 flows from the pressure oil inflow port 10 to the primary pressure side of the sequence valve 5. It is guided to the pressure reducing valve 12 via the spool tip portion 5e and the branch passage 10a to be formed.

There are two cylindrical oil chambers in the sliding portion of the spool 5a on the supply / discharge block 1 side, and the first oil chamber 1d from the primary pressure side 5e of the sequence valve is the secondary pressure side of the sequence valve 5. And is guided to the unload line 24 of the directional control valve, and the second oil chamber 1e from the spring chamber 1c communicates with the high pressure side 13a of the relief valve 13. A solenoid valve 14 for unloading the relief valve is installed on the vent line 14a of the relief valve 13. Further, the spool 5a is provided with a pressure oil inflow passage 15 (vertical hole 15a and horizontal hole 15b) for always communicating the primary pressure side 5e and the second oil chamber 1e.

FIG. 1 shows a state in which the pressure oil 9 is not supplied from the pump, or the relief valve 13 is in an unloading state even if the pressure oil is supplied. In FIG. 1, the pressure oil 9 from the pump enters the pressure oil inflow port 10 to the relief valve 13 via the primary pressure side 5e of the sequence valve 5, the pressure oil inflow path 15 of the spool 5a, and the second oil chamber 1e. Reach At this time, since the unload solenoid valve 14 is not excited, the vent line 14a of the relief valve 13 has a tank pressure due to the unload solenoid valve 14, so the relief valve is fully opened (unloaded). Therefore, only a very low pressure corresponding to the pressure loss in the supply / discharge block 1 is generated on the primary pressure side 5e, and the spool 5a is pressed in the pressure oil inflow direction (upward in FIG. 1) by the load of the spring 6 and the primary pressure side 5e. Does not communicate with the secondary pressure side (first oil chamber) 1d. Therefore, since no pressure oil is supplied to the directional switching valve unload line 24, the actuator does not operate even if the lever 25 of the switching valve portion is operated.

Further, in FIG. 1, even if the solenoid valve 23a or 23b of the directional control valve 2 is excited, the pressure oil supplied to the pressure reducing valve 12 has an extremely low pressure, so that the secondary pressure of the pressure reducing valve ( The pilot pressure) 11a also becomes low, and the small cylinder 22 of the switching valve does not operate. Therefore, the main spool 21 is not switched and the actuator does not operate. Therefore, in such a state, the unload solenoid valve 14 as a safety valve is effectively working. Further, at this time, the pressure oil 9 from the pump is unloaded (low pressure) by the relief valve 13, so that an energy saving circuit that does not generate unnecessary pressure is formed.

Next, when the unload solenoid valve 14 is excited, the vent line 14a of the relief valve 13 is closed, so that the relief valve operates and the pressure rises. Therefore, the pressure of the second oil chamber 1e and the pressure oil inflow port 10, that is, the primary pressure side 5e increases, and F = P × (π / 4) × d ² P: primary pressure side pressure d: on the spool 5a. When the force of the outer diameter of the spool sliding portion acts against the spring 6 and the force F becomes larger than the load set by the spring, the spool 5a is moved to the spring side (downward in FIG. 1) and the primary pressure side and the secondary pressure side ( The first oil chamber) 1d communicates with each other to supply the pressure oil to the unload line 24 of the direction switching valve 2.

At this time, a pressure P = Fs / ((π / 4) × d ² ) Fs: spring force is generated on the primary pressure side and the pressure oil inflow port. Since the pressure oil inflow port 10 is guided to the pressure reducing valve 12 via the branch passage 10a, the spring force Fs and the spool 5a are adjusted so that the pressure P generated at this time becomes larger than the operating pressure of the small cylinder 22 of the switching valve portion. By setting the outer diameter d of the sliding portion, the necessary pilot pressure can be obtained.

When the lever 25 is operated in such a state, the pressure oil is supplied to the direction switching valve 2, so that the actuator operates. Further, even when the solenoid valve 23a or 23b is excited, the pilot pressure required in the pilot line 11 is secured, so that the small cylinder 22 operates, the main spool 21 switches, and the actuator operates. As described above, according to the present invention, the operation of the sequence valve 5 can be controlled by the unload solenoid valve 14, and unnecessary pressure rise can be eliminated. The pressure in the unload line 24 rises due to the load of the actuator, the throttle of the main spool 21, etc., and the pressure force in the pressure oil inflow port 10 also rises, but the pressure oil inflow passage 15 opened in the spool 5a of the sequence valve 5 Since it always communicates with the high pressure side 13a of the relief valve 13 through the valve, the maximum pressure of the pressure oil 9 from the pump is controlled by the relief valve 13 as a result.

[0021]

[Effect of device]

 As described above, according to the present invention, the pressure oil supplied from the pump is guided to the high pressure side of the relief valve through the pressure oil inflow passage opened in the spool of the sequence valve, so that the supply / discharge block can be made small. It can be configured and only unload pressure of the relief valve and pressure loss of the valve passage and pipeline at the time of unloading suppresses heat generation and saves energy. In addition, since the pressure oil always passes through the sequence valve spool during both unloading and on-loading, there is no dust accumulation area and there is no risk of malfunction due to dust even during long-term unloading. It has been provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 shows a conventional hydraulic circuit diagram No. 1.

FIG. 3 shows a conventional hydraulic circuit diagram No. 2.

[Explanation of symbols]

 1 Supply / Discharge Block (Supply / Discharge Unit) 1d Secondary Pressure Side 2 Directional Switching Valve 5 Sequence Valve 5a Spool 5e Primary Pressure Side 9 Pressure Oil 10 Pressure Oil Inflow Port 11, 11a Pilot Line (Pilot Pressure Oil) 13 Relief Valve 13a Relief Valve High Pressure Side 15 Pressure oil inflow path 21 Main spool 22 Small cylinder (small actuator) 23a, 23b Solenoid valve 24, 24a Unload line

Claims (1)

[Scope of utility model registration request] 1. A pressure oil to which pressure oil is supplied, which has one or a plurality of directional switching valves for switching pilot pressure oil supplied to a small actuator for driving a main spool for controlling a hydraulic actuator by a solenoid valve or the like. The primary pressure side is connected to the inflow port and the pressure oil inflow port, and the secondary pressure side is connected to the unload line that is the pressure oil supply path to the main spool of the directional control valve. In a multiple directional switching valve provided with a supply / discharge section including a relief valve to be controlled, the pressure oil inflow port is connected to a spool that connects the primary pressure side and the secondary pressure side in accordance with the pressure on the primary pressure side of the sequence valve. A pilot pressure generating mechanism characterized in that a pressure oil inflow passage is formed to communicate with the high pressure side of the relief valve.