JPS5824690Y2 - spool valve - Google Patents

Description

[Detailed description of the invention] This invention has two ports that communicate with the fluid path of hydraulic equipment, and when the fluid pressure in the ports exceeds a certain level, the spool is moved from one port side to the other port side. This invention relates to a spool valve configured to allow pressure liquid to flow.

Such spool valves are used in various types in hydraulic circuits of various hydraulic equipment, for example, to lower the hydraulic pressure when the hydraulic pressure exceeds a certain pressure, and to maintain the hydraulic pressure constant.

FIG. 1 shows such a known spool valve, as shown in the figure:
Reference numeral 1 denotes a valve body that is attached to, for example, a hydraulic device, and a first port 2 and a second port 3 provided in this valve body 1 are in communication with a liquid path.

A spool 5 having a generally cylindrical shape is slidably provided in the center of the valve body 1, and a lid 4 is integrally attached to the end of the valve body 1.

At the center of the spool 5, a first spool core 6 and a second spool core T are also slidably disposed relative to the spool 5.

A ring groove 8 communicating with the first port 2 is provided on the outer periphery of the spool 5, and a first passage 9 is provided between the ring groove 8 and the center of the spool 5.

On the other hand, the spool 5 is provided with a second passage 10 that communicates with the second port 3, and is adapted to apply pressure liquid to a pressure receiving portion 5a formed at the center of the spool 5.

A compression spring 11 is interposed between the spool 5 and the lid 4, and presses the spool 5 leftward in the drawing.

Therefore, if the hydraulic pressure on the first port 2 side is below a certain pressure, the spool 5 will be held in the state shown in the figure, but if the hydraulic pressure on the first port 2 side increases, this hydraulic pressure will cause the ring groove 8 to 1st
The second spool core 1 is pushed to the right through the passage 9.

As a result, the spool 5 moves to the right against the spring 11, the first port 2 and the second boat 3 are communicated through the ring groove 8, and the pressure liquid on the first port 2 side is transferred to the second port 2. The liquid flows into the port 3 side, and the hydraulic pressure on the first port 2 side is kept constant.

Further, when the hydraulic pressure becomes lower than a certain pressure, the spool 5 moves to the left by the force of the spring 11, and the flow of pressure oil stops.

On the other hand, when the reverse operation occurs, that is, the pressure on the second port 3 side increases, this oil pressure is applied to the pressure receiving part 5a of the spool 5 through the second passage 10, pressing the spool 5 to the right and also moving the spool 5 to the right. In this way, the second port 3 and the first port 2 are connected, and the pressurized liquid on the second port 3 side flows into the first port 2 side.

When the oil pressure on the second port 3 side falls below a certain pressure, the spool 5 moves to the left and the flow of pressure oil stops.

In the above-mentioned known spool valve, the pressure liquid flows from the first port 2 to the second port 3 and the second port 3
In the case where the flow flows from the spool 5 to the first port 2,
The sum of the fluid force and the anti-spring force acting on the spring will be different.

In an extreme situation where the pressure oil flows rapidly at the edge of the spool, the change in momentum is large, so a thrust is generated on the spool that impedes the movement of the spool, so if the direction of the flow of pressure oil is reversed, Since the direction of this thrust is completely different, there is a drawback that the override characteristics (valve inlet pressure and passing flow rate characteristics) of the conventional spool valve shown in FIG. 1 exhibit different characteristics depending on the flow direction.

The above-mentioned known spool valve is structurally simple in that the compression spring only needs to be arranged on one side of the spool, so it is suitable for applications where the override characteristic is not important. However, for example, such a spool valve is used in a brake valve. In this case, the characteristics of the brake valve differ depending on whether the hydraulic actuator rotates in the normal direction or in the reverse direction, which is inconvenient.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a spool valve which is simple and compact in construction and whose override characteristics are the same in the direction of flow.

According to the present invention, a spring is interposed between the spool and the valve body, the pressure receiving portions of the spool communicating with the first and second ports are formed in directions that move the spool in opposite directions, and The spring is provided between first and second spring seats that are movable with the spool, and the first and second spring seats are provided at positions where they can be engaged with the spool and the valve body, respectively.

Therefore, the spool moves in the opposite direction when pressure oil flows from one port to the other port and when it flows from the other port to one port, so the drag force on the spool due to fluid force, that is, the viscosity of the pressure oil is Since the direction is always the same, the override characteristic does not change depending on the direction of the pressure oil.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.

That is, the valve body 1, the first port 2, the second port 3, the lid 4,
Spool 5, first spool core 6, first passage 9, spring 11
is substantially the same as that shown in FIG.

The spool 5 is provided with a first ring groove 8a that communicates with the first port 2, a second ring groove 8b that communicates with the second port 3, and a first ring groove 8a that communicates with the first port 2.
a and the pressure receiving part 5a of the spool 5 are connected by a first passage 9, and the second ring groove 8b and the end chamber 12 of the spool 5 are connected by a second passage 10, and the end chamber 12 has a second passage. A spool core 13 is installed inside.

A second spring seat 16 and a first spring seat 15 are provided at the left and right ends of the spring 11, and the spool 5 is pressed leftward via the second spring seat 16, and the first spring seat 15'J? and is configured to be pushed rightward via a snap ring 14 fixed to the left end of the spool 5.

That is, the first spring seat 15 is connected to the spool 5'J? via the snap ring 14 provided at the end of the spool 5. The second spring seat 16 is provided at a position where it can be engaged with the lid 4 which is integral with the valve body and constitutes a part of the valve body, and the second spring seat 16 also engages with the stepped portion 20 of the spool and the stepped portion 21 formed on the valve body. It is located in a position where it can be matched.

When the pressure liquid flows from the first port 2 side to the second port 3 side during operation, it is similar to the conventional technology shown in Fig. 1, but the liquid pressure on the second port 3 side is constant. When the pressure exceeds the pressure, the pressure liquid flows through the second passage 10 and the pressure receiving part 12a of the end chamber 12.
and press the spool 5 to the left.

This pressing force compresses the spring 11 via the snap ring 14 and the first spring seat 15, and the spool 5 moves to the left.

However, the second spring seat 16 separates from the spool step 20 but remains engaged with the valve body step 21.

As a result, the second port 3 is communicated with the first port 2 via the second ring groove 8b.

The direction of the fluid force of the pressure oil at this time is the same as the direction of the compression force on the spring 11, and therefore the force relationship is similar to that when the pressure fluid flows from the first port 2 to the second port 3. ing.

As described above, in the present invention, the sum of the fluid force and spring force acting on the spool is the same regardless of the direction of the fluid pressure, so the override characteristics are the same, and the control function as a valve device is enhanced. It is effective.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a control valve device according to the prior art, and FIG. 2 is a cross-sectional view showing an embodiment of the control valve device according to the present invention. 1... Valve body, 2... First port, 3... Second
port, 4...lid, 5...spool, 6...first spool core, 7...second spool core, 8...ring groove, 8a...first ring groove , 8b... second ring groove, 9... first passage, 10... second passage, 1
DESCRIPTION OF SYMBOLS 1... Spring, 12... End chamber, 13... Third spool core, 14... Snap ring, 15... First spring seat, 16... Second spring seat, 20...・Stepped part of spool, 21...Cut of valve body.

Claims (2)

[Scope of utility model registration request] (1) It has two ports that communicate with the fluid path of the hydraulic equipment, and is configured so that when the fluid pressure in the ports exceeds a certain level, the spool is moved to allow pressure fluid to flow from one port side to the other port side. In this spool valve, a spring is interposed between the spool and the valve body, and the pressure receiving portions of the spool communicating with the first and second ports are formed in directions that move the spool in opposite directions, and The spring is provided between first and second spring seats that are movable with the spool, and the first and second spring seats are provided at positions where they can be engaged with the spool and the valve body, respectively. Features a spool valve. (2) The scope of the utility model registration claim is that the pressure receiving portion is an end wall of a chamber formed by a recess provided at both ends of the spool and a spool core that is fitted into the recess and has one end in contact with the valve body. The spool valve described in item 1.