JPS5827427B2 - Vacuum prevention and pressure control valve - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vacuum prevention/pressure control valve, which opens when the pressure in a pressure circuit such as a cylinder exceeds a set pressure, and opens when the pressure circuit becomes vacuum. The present invention also relates to a vacuum prevention/pressure control valve which opens to prevent vacuum in the circuit.

Generally, in order to prevent overpressure in a hydraulic circuit, etc. and to prevent the generation of vacuum in the circuit, a vacuum prevention valve and a pressure control valve are provided separately. ing.

However, in such cases at least 2
Since it is necessary to provide each valve, there are problems in terms of space, and the circuit itself cannot be made compact.

Therefore, in order to solve the above-mentioned disadvantages, a valve body has been proposed in which a single valve body functions as both a vacuum prevention button and an overpressure prevention function.

That is, FIG. 3 is a longitudinal sectional side view of a device in which both the vacuum prevention and overpressure prevention functions are performed by one valve body. A valve body e is provided to open and close a valve chamber d provided between the drain port c and the drain port c, and a check valve body f is provided within the valve body e to allow flow only from the drain port c side to the cylinder port b side.
A communication passage is provided from the cylinder port b side to the second valve chamber g provided in the valve body e, which allows flow while restricting the flow rate, and communicates with the second valve chamber g to the inner cylinder i. Third
A valve chamber j is provided, and a pilot valve body l is provided on the valve seat k located between the second valve chamber g and the third valve chamber j, and a pilot valve body l is provided on the circumferential surface of the inner cylinder 'i. , a through hole m is provided which communicates the third valve chamber j with the drain port c through the space between the outer cylinder a and the valve body e.

When the pressure in the cylinder port b rises and the pressure in the second valve chamber g rises and exceeds the set pressure of the pilot valve element l, the pilot valve element l is pushed open and the second valve chamber g increases.
Pressure oil in the valve chamber g flows to the drain port C via the through hole m and the gap between the outer cylinder a and the valve body e.

Therefore, the pressure in the second valve chamber g suddenly decreases, the valve body e is opened, and the hydraulic pressure in the cylinder port b flows out to the drain port c.

In this way, the pressure inside the second valve chamber g is reduced to the pilot valve body l.
When the pressure falls below the set pressure, the pilot valve element l closes, and the valve element e is closed by the pressure on the second valve chamber side of the valve element e, and functions as a pressure control valve.

On the other hand, when the pressure inside the cylinder port b becomes lower than the pressure on the drain port C side, and the force applied to the valve body e on the drain port C side becomes greater than the force pressing the valve body e against the valve seat d, the valve body e is opened, oil flows from drain port c to cylinder port b, and a vacuum prevention effect is performed.

. However, in order to ensure the vacuum prevention effect in such a position, it is necessary to increase the difference between the inner diameter D2 of the second valve chamber g and the diameter of the valve seat d. If =D is increased, there are problems such as loss of function as a pressure control valve (safety valve).

In addition, when the valve body e returns to the neutral position after acting as a suction valve that performs a vacuum prevention action, the check valve body f is seated against the valve seat provided on the valve body e, so that the cylinder port When the b side suddenly changes from a vacuum state to a pressure state,
Although the pressure in the cylinder port b is transmitted to the second valve chamber g through the communication passage, the transmission of the pressure is delayed due to the resistance of the communication passage, and the seating of the valve body e on the valve seat is delayed, causing the cylinder There are inconveniences such as pressure in port b escaping to drain port c.

In view of these points, it is an object of the present invention to provide a vacuum prevention/pressure control valve that does not have the above-mentioned drawbacks, can be used in a large capacity hydraulic actuator, and can be miniaturized.

In order to achieve the above object, the present invention provides a base body having a pressure circuit connected to a cylinder etc. and a tank circuit connected to a tank etc., and a partition wall whose one end divides the pressure circuit and tank passage of the base body. A valve with a through hole in the side wall that opens into the tank passage.It is installed so that it can slide in the axial direction within the cylinder, and is always attached to the pressure circuit side of the cylinder. A main plunger whose tip is pressure-contacted to a valve seat formed at the open end, and when overpressure or vacuum is generated in the pressure circuit, the main plunger is moved back against the pressure-contact force to connect the pressure circuit and the tank circuit. The main plunger is fitted in an axial hole provided in the main plunger so as to be able to slide in the axial direction to some extent, is biased toward the pressure circuit side, and connects the front and rear of the main plunger in the forward position to the retreat position. a poppet valve having a through hole so that the communication is narrowed; and a poppet valve that is fitted onto the main plunger so as to be slidable in the axial direction, and is protruded from the rear end of the main plunger by pressure from the tank circuit side. a sleeve that biases the main plunger in a direction away from the valve seat through a flange provided at the rear end of the valve cylinder, and a sleeve that biases the main plunger in a direction away from the valve seat; The invention is characterized in that it is provided with a valve that opens when the valve is opened and discharges the pressure oil in the section into the tank circuit.

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a base body having a cylinder chamber, a pressure passage 2 button communicating with the cylinder chamber, etc., and a tank passage 3 connected to a tank etc., and a cylindrical jacket at the end of the base body 1. The proximal end of the mantle 4 is screwed into a button, and an end plug member 5 is inserted and screwed into the distal end of the mantle 4.

Inside the mantle 4, there is a cylindrical valve concentrically with the mantle 4.
A cylinder 6 is provided.

One end of the valve cylinder 6 is inserted into the partition wall 1a between the pressure passage 2 and the tank passage 3 of the base body 1, and the other end is fitted onto the small diameter portion 5a of the end plug member 5, An annular gap S is formed between the valve housing 6 and the inner surface of the jacket 4.

The valve housing 6 opens into the pressure passage 2 at one end thereof, has a valve seat 6a formed on the inner peripheral surface of the opening end, and further has a through hole 7 opened into the tank passage 3 in the side wall. is drilled.

Valve: A sleeve 8 is disposed in the cylinder 6 so as to be slidable in the axial direction, and a main plunger 9 is disposed in the sleeve 8 so as to be slidable in the axial direction. The tip of the plunger 9 is pressed against or separated from the valve seat 6a,
This allows the pressure circuit 2 and the tank circuit 3 to be disconnected or communicated with each other.

The sleeve 8 has an annular flange 1 protruding from the inner surface of the valve cylinder 6 closer to the end plug member than the through hole 7.
0 and a flange 9a protruding from the rear end of the main plunger 9, and its relative axial movement is restricted.

The main plunger 9 is also provided with an axial hole 9c having a tapered portion 9b that widens toward the pressure circuit 2 side, and the poppet valve 11 is slidably mounted in the axial hole 9c in the axial direction. ing.

The poppet valve 11 has a radial hole 11a formed near its front end (pressure circuit side), and a through hole 11b extending rearward from the radial hole 11a and opening at its rear end. In addition, the poppet valve 11 is biased forward by a spring 12 interposed between the flange 11c of the poppet valve 11 and the front end surface of the end plug 5.

On the other hand, a through hole 13 extending in the axial direction is formed in the end plug member 5, and a valve seat 14 having a small axial through hole 14a projecting therein is attached to the tip of the through hole 13.
The rear end of the small through hole 14a (
Needle valve 15 that seals the opening (right end in the figure)
are pressed together by a spring 16.

A screw adjuster 17 is screwed into the opening at the rear end of the through hole 13 of the bent end plug member 5, and the screw adjuster 17 receives the rear end of the spring 16 and clicks, and the pressing force can be adjusted by adjusting the screw.・Insert the ring gasket 1819 into the screw adjuster 17 and tighten the hexagonal nut 20.
A hexagonal cap nut 21 is used to prevent loosening.

The end plug member 5 is further provided with a radial communication hole 22 that opens into the through hole 13 at a position rearward from the position of the needle valve 15 (on the opposite side from the valve seat 14). This allows the through hole 13 to communicate with the gap S between the mantle 4 and the valve 776.

Reference numbers 23, 24, 25, and 26 in the figure are sealing O-rings, respectively.

When the pressure in the pressure circuit 2 is below the set pressure, the needle valve 15 is pressed against the valve seat 14 by the spring 16, thereby sealing the small through hole 14a.

Therefore, the pressure applied to the flange end face of the main plunger 9 is balanced with the pressure in the pressure circuit, but the spring 1
As shown in FIG. 1, the tip of the main plunger is pressed against the valve seat 6a of the valve casing 6 by the pressing force of 2.

Therefore, when the pressure in the pressure circuit 2 exceeds the set pressure, the pressure is applied to the hole 11a button of the poppet valve 11 and the through hole 1.
1b, the needle valve 15 is applied, and the needle valve 15 is moved to the right against the spring 16 in the figure.

Therefore, the pressure oil that has been operating on the flange side end surface of the main plunger 9 flows out into the tank passage 3 through the small through hole 14a of the valve seat 140, the communication hole 22, and the annular gap S.

As a result, the pressure in the second valve chamber 27 decreases relative to the pressure in the pressure circuit 2, and the poppet valve 11 is also moved to the right against the spring 12.

Then, the flow area of the radial hole 11a of the poppet valve 11 is narrowed by the tapered part 9b of the axial hole 9c provided in the main plunger 9, and the pressure of the pressure oil flowing into the second valve chamber 27 through the through hole 11b is reduced. falls further.

Therefore, the pressure applied to the rear end surface of the main plunger 9 decreases, and the pressure applied to the end surface of the main plunger 9 on the pressure circuit 2 side causes the main plunger 9 to move to the right, and the pressure circuit 2
and the tank passage 3 communicate with each other, so that a portion of the pressure oil in the pressure circuit 2 flows out into the tank passage 3, and overpressure in the pressure oil tank 2 is prevented.

When the oil pressure in the pressure circuit 2 drops below the set pressure in this way, the needle valve 15 is moved to the left by the spring 16 and is pressed against the valve seat 14.

As a result, the pressure in the second valve chamber 27 increases and becomes the same pressure as the pressure circuit 2, and the poppet valve 11 is moved to the left by the spring 12, and the main plunger 9 is also moved to the left by the flange 11c of the poppet valve, so that the tip of the valve seats the valve seat. 6a, resulting in the state shown in FIG.

On the other hand, when the pressure in the pressure circuit 2 decreases and becomes a vacuum state, the pressure in the second valve chamber 27 decreases through the through hole 11b of the poppet valve 11, so that the pressure in the tank circuit 3 decreases to the sleeve 8. The main plunger 9 is moved to the right via the flange 9a, and the main plunger 9 is separated from the valve seat 6a, and the main plunger 9 is moved from the tank circuit 3 into the pressure circuit 2. Oil flows into the tank and the vacuum is prevented.

In this case, since the poppet valve 11 moves integrally with the main plunger 9, a sufficient passage area of the radial holes 11a and the through holes 11b provided in the poppet valve 11 is ensured.

Therefore, even if the pressure circuit 2 side suddenly changes from a vacuum state to a pressure state, the pressure in the second valve chamber 27 correspondingly increases rapidly, and the spring 12 and poppet pulp 1
The main plunger 9 is quickly seated on the valve seat 6a by the pressure applied to the flange llc of No. 1, and the pressure in the pressure circuit does not escape to the tank passage.

Since the present invention is configured as described above, a single valve device can serve as both a vacuum prevention valve and a pressure control valve, and unlike the conventional hydraulic actuated device, two valves are used for pressure control and vacuum prevention.
There is no need to provide separate valves, and only the main plunger has both functions, so the oil passage can be enlarged, the number of parts is small, and it can be used in a compact and large-capacity hydraulic actuator. In this case, a sleeve is slidably fitted over the main plunger in the axial direction, and when acting as a suction valve, the main plunger is actuated via the sleeve, and when acting as a pressure control valve, the sleeve is free. Therefore, under normal conditions, the pressure receiving area at the front and rear of the main plunger can be formed to be almost the same, and the main plunger can be opened rapidly by opening the valve provided at the rear end of the housing, improving its performance as a safety valve. be able to.

In addition, the main plunger is provided with a poppet pulp that is biased toward the pressure circuit side and has a through hole that communicates the front and back of the main plunger, so even if the pressure circuit side suddenly changes from a vacuum state to a pressure state, The main plunger is quickly seated on the valve seat, and the pressure in the pressure circuit is prevented from escaping into the tank passage.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional side view of the vacuum prevention/pressure control valve of the present invention when the button is pressed at the set pressure, Fig. 2 is a cross-sectional side view of the opposite valve in the vacuum prevention operating state, and Fig. 3 is a longitudinal cross-section of a conventional pressure control valve. FIG. 1...Base, 2...Pressure circuit, 3...
...tank circuit, 4...coat, 5...
...End plug member, 6...Valve...Using, 7...
...Through hole, 8...Sleeve, 9...
・Main plunger, 11...Poppet pulp, 1
4... Valve seat, 15... Needle valve, 22... Radial hole, S...
- Annular gap.

Claims (1)

[Claims] 1 A base body having a pressure circuit connected to a cylinder etc. and a tank circuit connected to a tank etc., one end of which is inserted into a partition wall of the base body that divides the pressure circuit and the tank passage, and the tank passage is connected to the side wall. A valve with a through hole that opens into the housing is installed so as to be able to slide in the axial direction within the housing, and its tip is normally attached to the valve seat formed at the open end of the housing on the pressure circuit side. A main plunger that is pressed back against the pressure contact force when overpressure or vacuum is generated in the pressure circuit to connect the pressure circuit and the tank circuit, and a shaft provided on the main plunger. It is fitted in the direction hole so as to be able to slide to some extent in the axial direction, is biased toward the pressure circuit side, and communicates the front and rear of the main plunger when in the forward position, and narrows the communication when the button is in the backward position. a poppet valve having a through hole;
The main plunger is fitted onto the main plunger so as to be slidable in the axial direction, and the main plunger is moved in a direction away from the valve seat via a flange that projects from the rear end of the main plunger by pressure on the tank circuit side. and a valve that is installed at the rear end of the valve housing and opens when the pressure applied to the rear end surface of the main plunger exceeds a set value, and discharges the pressure oil in the part into the tank circuit. A vacuum prevention and pressure control valve characterized by the provision of a vacuum prevention and pressure control valve.