JP2001099108A - Multiple valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiple valve device capable of limiting supply of operating oil to a selector valve mechanism by a simple structure and capable of realizing an automatic decelerating function of an actuator such as a cylinder. SOLUTION: Supplied operating fluid is divided into an priority flow and a surplus flow by a priority valve mechanism 2, the surplus flow discharged from the priority valve mechanism 2 is guided to input ports of selector valves 31A, 31B housed in one or a plurality of selector valve mechanisms 3A, 3B stacked in the priority valve mechanism through a parallel line 4, an emergency valve 61 provided between the parallel line 4 and a tank line 5 communicated with a tank is opened under specified conditions, and the parallel line 4 is communicated with the tank line 5 through a flow control valve 67 provided downstream of the emergency valve 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple valve device which is suitably used for industrial vehicles such as forklift trucks and the like, and has a switching valve mechanism configured to be capable of being repeatedly stacked.

[0002]

2. Description of the Related Art As shown in FIG. 6, a prior art multiple valve apparatus 100 of this type has a priority valve mechanism 102 and a plurality of switching valve mechanisms 103 arranged in a stack downstream of the priority valve mechanism 102. Are known. As shown in FIG. 7, the high-pressure hydraulic oil discharged from a hydraulic pump (not shown) is received at a port P, and is preferentially diverted to, for example, a steering operation port PF by a priority valve mechanism 102 as a component thereof. The excess flow is configured to be guided to an input port 132 of a switching valve 131 built in the switching valve mechanism 103 via a parallel line 104. By manually operating the switching valve 131 via the operation lever L, actuators such as the tilt cylinder TS and the lift cylinder LS can be driven by the excess flow.

[0003]

On the other hand, in recent forklift trucks, the operation speed of the actuator is limited in the vicinity of the stroke end or in a load state in which the balance of the vehicle is easily lost in order to prevent the load from collapsing or the vehicle from overturning. A function has been proposed.

However, it has been considered that such a demand cannot be met by the above-mentioned conventional manually operated multiple valve apparatus. Therefore, an automatic operation type such as using an electromagnetic proportional valve for the switching valve mechanism has been considered. Things are being developed.

[0005] However, such a device has a disadvantage that it is expensive and disadvantageous in cost. In addition, for convenience, a method of unloading all of the discharge oil from the pump before leading it to the multiple valve device has been considered.
During the operation of the automatic stop function, the function of the priority valve mechanism is also stopped, so that the supply of high-pressure hydraulic oil to the steering or the like is interrupted.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a multiple valve device that can limit the supply of hydraulic fluid to only a switching valve mechanism with a simple configuration and realize automatic deceleration of an actuator such as a cylinder. The main purpose is.

[0007]

In order to solve the above-mentioned problems, a multiple valve device according to the present invention divides the supplied hydraulic fluid into a priority flow and an excess flow by a priority valve mechanism, The excess flow discharged from the valve mechanism is guided through a parallel line to an input port of a switching valve built in one or a plurality of switching valve mechanisms stacked on the priority valve mechanism, and under predetermined conditions, to the parallel line and the tank. The parallel line is communicated with the tank line through a flow control valve provided downstream of the emergency valve by opening an emergency valve provided between the tank line and the open tank line.

[0008] According to this structure, the emergency valve can be interposed in the parallel line without impairing the function of the priority valve mechanism and without employing expensive and expensive members such as an electromagnetic proportional valve. With an inexpensive configuration, it is possible to realize automatic deceleration of an actuator required for a fork relat truck or the like.

The predetermined condition is set in accordance with, for example, a horizontal position or a height position of a mast in an industrial vehicle such as a forklift truck, and is generally obtained by condition detecting means such as a position sensor. It is. However, in order to suitably cope with such a configuration and to simplify the structure, it is preferable that the emergency valve be electromagnetically driven based on information from the condition detecting means.

Further, by simply adding an emergency valve block to an existing multiple valve device, the present invention can be realized easily and at extremely low cost, and various effects such as promotion of introduction to users can be achieved. To achieve this, it is desirable that the emergency valve be housed in an emergency valve block configured to be compatible with the switching valve mechanism.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Multiple valve device 1 according to the present embodiment
As shown in FIGS. 1 and 2, a multi-stack system is provided, for example, on a forklift truck F, and has a priority valve mechanism 2 and two switching valve mechanisms stacked downstream of the priority valve mechanism 2. 3A, 3B, an emergency valve block 6 incorporating an emergency valve 61 and a flow control valve 67 downstream thereof
And

As shown in FIG. 5, the forklift truck F is a known forklift truck. By operating a lift lever LL, a lift cylinder LS (shown in FIG. 2) is driven to move the pawl NL up and down, and the tilt lever TL is moved. Has at least a function of driving the tilt cylinder TS to tilt the mast MT back and forth. Further, in this embodiment, a first condition detecting means (not shown) such as a proximity switch capable of detecting a state where the claw NL is horizontal is attached to, for example, the tilt cylinder TS, so that the claw NL becomes higher than a predetermined height. A second condition detecting means (not shown) such as a proximity switch capable of detecting that the operation has occurred is attached to, for example, the lift cylinder LS.

The priority valve mechanism 2 integrates various valves such as a priority valve main body 23 into a main body 22 having a hydraulic path formed therein, and converts the supplied hydraulic fluid into a priority flow and an excess flow. A port P serving as an inlet for high-pressure hydraulic oil discharged from a hydraulic pump (not shown), a tank port T2 communicating with a tank (not shown), and a steering operation assist circuit (not shown) And a port PF that preferentially discharges hydraulic oil required when a steering operation is performed.

The switching valve mechanisms 3A and 3B are provided with three inputs 3 to valve sections 32A and 32B having a hydraulic path formed therein.
The output type switching valves 31A and 31B are integrally incorporated. One switching valve mechanism 3A has an output port A1 connected to the lift cylinder LS. The switching valve 31A has a lift lever LL at its operation end 34A.
Are mechanically connected, and the internal path is switched by manual operation of the lift lever LL, and the lift cylinder LS
Is to sink. The other switching valve mechanism 3B includes two output ports A2 and B2 connected to the tilt cylinder TS, respectively. The switching valve 31B has a tilt lever TL mechanically connected to an operation end 34B thereof, and the internal path is switched by manual operation of the tilt lever TL to cause the tilt cylinder TS to protrude and retract. In the present embodiment, as shown in FIG.
3B is connected to the priority valve mechanism 2 and stacked. In addition,
It is also possible to stack three or more switching valve mechanisms 3A, 3B according to the number of actuators such as cylinders.

As shown in FIG. 3, the emergency valve block 6 has a manifold block 6 having a hydraulic passage formed therein.
2 integrally incorporates an emergency valve 61 and a flow control valve 67 on the downstream side thereof, and has mounting compatibility with the switching valve mechanisms 3A and 3B. The emergency valve 61 is a pilot operated type balance piston valve, and among the internal hydraulic paths of the emergency valve block 6, an unload path 63 that connects a hydraulic path forming the tank line 5 and a hydraulic path forming the parallel line 4. Is placed on top. Then, the solenoid valve 65 provided on the pilot path 64 is opened to open. The solenoid valve 65 is opened and closed by a signal from the above-described first and second condition detecting means. A flow control valve 67 is disposed on the unload path 63 downstream of the emergency valve 61. As the flow control valve 67, a pressure compensation type flow control valve having a property of flowing a constant flow rate with little influence of the working pressure is used. In this embodiment, as shown in FIG. 1, the emergency valve block 6 is stacked outside the switching valve mechanism 3B located at the most downstream position. Further, a rear cover RC shown in FIGS. 1 and 4 is attached to the outside of the emergency valve block 6.

The internal hydraulic circuit configuration of the multiple valve device 1 in which the switching valve mechanisms 3A, 3B and the like are arranged in a stack will be described below.

The excess flow from the priority valve mechanism 2 is
3 is discharged from the surplus flow output port 21. The surplus flow output port 21 is connected to the respective switching valve mechanisms 3A, 3B via the parallel line 4 formed by stacking the switching valve mechanisms 3A, 3B. Are connected to the first input ports 32A and 32B of the switching valves 31A and 31B. The first input ports 32A and 32B are manually operated by the lift (tilt) levers LL and TL to switch the switching valves 31A and 31B, respectively. Is communicated with
The lift cylinder LS and the tilt cylinder TS can be driven by the excess flow. The priority valve mechanism 2 and the switching valve mechanism 3 connected in a stack
A tank line 5 is formed in A and 3B, and this tank line 5 is configured to communicate with a tank port T2 of the priority valve mechanism 2 and a tank port T1 provided in the rear cover TS. This parallel line 4 and tank line 5
Is connected via the unload path 63 provided in the emergency valve block 6 as described above, and communicates through the flow control valve 67 when the emergency valve 61 provided on the unload path 63 is opened. .

Next, the operation of the multiple valve device 1 according to the present embodiment will be described. When the lift lever LL is operated to extend the lift cylinder LS and raise the pawl NL, the output signal of the second condition detecting means is switched at the time when the lift cylinder LS reaches a predetermined height, whereby the solenoid valve 65 is opened. Then, the emergency valve 61 is opened. As a result, the parallel line 4 communicates with the tank line 5 via the flow control valve 67, the hydraulic oil supplied to the lift cylinder LS is unloaded, and the raising operation of the pawl NL is performed by the lifting operation of the lift lever LL. Despite this, automatic deceleration is performed. The switching valve mechanism 3
A has a load check valve 33A incorporated therein.
This prevents the hydraulic oil in the lift cylinder LS from flowing backward to lower the pawl NL. In this way, in the present embodiment, automatic deceleration of the lift is realized.

On the other hand, while the tilt cylinder TS is extended and contracted by operating the tilt lever TL to tilt the mast MT back and forth, when the pawl NL reaches the preset tilt position, the first condition detecting means is activated. The output signal is switched, whereby the solenoid valve 65 is opened and the emergency valve 61 is opened. As a result, the parallel line 4 communicates with the tank line 5 via the flow control valve 67, the hydraulic oil supplied to the tilt cylinder TS is unloaded, and the forward / backward tilting of the mast MT is performed regardless of the operation of the tilt lever TL. Automatic deceleration. A tilt lock valve 33B is incorporated in the switching valve mechanism 3B to prevent the hydraulic oil in the tilt cylinder from flowing backward during the tilt forward tilting operation, thereby preventing the mast MT from tilting forward. In this way, in this embodiment, automatic deceleration of horizontal movement is realized.

Therefore, such a multiple valve device 1
According to the above, without deteriorating the function of the priority valve mechanism 2 and without employing expensive and expensive members such as an electromagnetic proportional valve, an extremely simple and inexpensive configuration, automatic deceleration of the lift or horizontal movement can be achieved. It is possible to realize an automatic deceleration function.

In particular, in this embodiment, the emergency valve 61 can be electromagnetically driven by the information from the condition detection sensor, so that the structure of the emergency valve can be simplified more easily.

The emergency valve block 6 includes the switching valve mechanism 3
A and 3B are interchangeable with each other and can be stacked at any position between or between the switching valve mechanisms 3A and 3B. Therefore, the emergency valve block 6 is simply added to the existing multiple valve device 1. This embodiment can be realized easily and at extremely low cost. As a result, various effects such as promotion of introduction to the user can be achieved.

The present invention is not limited to the embodiment described above. For example, although the emergency valve block is incorporated in the last series of the switching valve mechanism in the above-described embodiment, the same operation and effect can be obtained in any position. In addition, the present device can be applied to not only forklift trucks but also various industrial vehicles. Further, an emergency valve may be built in the priority valve mechanism or the rear cover. In addition, the present invention is not limited to the above illustrated examples, and various changes can be made without departing from the gist of the present invention.

[0024]

As described in detail above, according to the multiple valve apparatus of the present invention, high-grade and expensive members such as an electromagnetic proportional valve can be employed without impairing the function of the priority valve mechanism. In addition, an automatic deceleration function of an actuator required for a forklift truck or the like can be realized with an extremely simple and inexpensive configuration.

[Brief description of the drawings]

FIG. 1 is a side view showing a multiple valve device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the multiple valve device according to the embodiment.

FIG. 3 is a schematic sectional view showing the internal structure of the emergency valve block in the embodiment.

FIG. 4 is a front view of a rear cover in the embodiment.

FIG. 5 is an overall side view showing the forklift according to the embodiment.

FIG. 6 is a side view showing a conventional multiple valve device.

FIG. 7 is a hydraulic circuit diagram of a conventional multiple valve device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multiple valve apparatus 2 Priority valve mechanism 21 Excess flow output port 3A, 3B Switching valve mechanism 31A, 31B Switching valve 32A, 32B Input port 4 Parallel line 5 Tank line 61 Emergency valve 67 Flow control valve

Claims (1)

[Claims] 1. A priority valve mechanism capable of diverting a supplied working fluid into a priority flow and a surplus flow and discharging the same, and one or more switching valve mechanisms including a switching valve and stacked on the priority valve mechanism. A parallel line for guiding the excess flow discharged from the priority valve mechanism to the input port of the switching valve,
An emergency valve communicating with the tank line that connects the parallel line to the tank under predetermined conditions, and a flow control valve provided downstream of the emergency valve.