JPH05141544A - Poppet type bidirectional operation flow passage opening/ closing valve and hydraulic circuit using the same - Google Patents

Abstract

PURPOSE:To allow stable flow passage control by making up a two-port poppet type bidirectional operation flow passage opening/closing valve with a flow passage open only when total power from pressure on a primary port and/or a secondary port is greater than power determined by initial reaction of a spring. CONSTITUTION:A poppet valve element 4 is stored in a valve body 10, in which a valve seat opening (seat) 3 is provided on the way of a perpendicular inside passage, and has the end tapered to be seated on the seat 3 on the way of a slope. In this way, the first pressurized area A1 which is subjected to operation of pressure oil pressure P1 on the first port 1 side is formed in an area A and the second pressurized area A2 which is subjected to operation of pressure oil pressure P2 on the second port 2 side is formed in an area B-A, where the opening area of the seat 3 is A and the cross section of the valve element 4 is B. When a relationship of P1, P2 to initial reaction FS of a valve closing spring 6 is sham as A1.P1>=FS or A2.P2>=FS, the valve element 4 is deseated from the seat 3 to make both ports 1, 2 communicate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-port type poppet type bidirectional operation flow path on-off valve and a hydraulic circuit using the same, and in particular, electric / hydraulic pilot valve control utilizing a part of self-discharge pressure. When the actuator is operated in a desired control pattern by the variable pump that changes the discharge pressure and / or the discharge amount based on the control command by the The present invention relates to a flow path opening / closing valve, a hydraulic circuit using the same, and a variable pump equipped with such a flow path opening / closing valve.

[0002]

2. Description of the Related Art In recent years, a hydraulic actuator for controlling a series of sequential operations of a plastic injection molding machine or the like has a desired pressure.
When controlling the operation according to the flow rate change pattern, the conventional pump discharge pressure oil is changed to the control method by various control valves, and the electric / hydraulic pilot valve control that uses a part of the self discharge pressure is used to discharge based on the control command. A method of operating an actuator in a desired control pattern by a variable pump that changes pressure and / or discharge amount has become mainstream.

However, in this type of variable pump, since pilot control by self-discharge pressure is adopted, it becomes difficult to secure the pilot pressure of the pump itself when the load pressure becomes low, which makes it difficult to control the discharge flow rate. There are drawbacks such as the actuator going out of control. In order to solve this drawback, for example, JP-A-62-2
As disclosed in Japanese Patent No. 70803, it has been attempted to provide a sequence valve or a check valve in the pump discharge line. However, when only the sequence valve is provided, if the pump discharge pressure is reduced to a pressure equal to or lower than the set pressure of the sequence valve, Since the pump discharge port and the circuit on the actuator side are shut off by the sequence valve, the pressure on the actuator side cannot be reduced according to the drop in discharge pressure of the pump.
In the case of a check valve, the pump can raise the pressure on the actuator side but cannot lower the pressure.Therefore, the surge pressure remains on the actuator side, and in reality, the pressure on the downstream side is reduced by the switching valve provided in the actuator side circuit. There was a problem that it could not be lowered until it was opened to the tank line.

[0004]

[Problems to be Solved by the Invention]
When using a sequence valve, it can be solved by adding a reverse direction check valve in parallel to the sequence valve and reducing the pressure on the actuator side to the cracking pressure of the check valve. When controlling with a low load pressure, the response and control stability of the sequence valve are impaired, causing hysteresis and pressure oscillation of the secondary side pressure.Since the sequence valve itself is a spool type, its leakage amount cannot be ignored and the sequence Depending on the shape of the control part of the valve spool, not only the above-mentioned pressure oscillation but also the pressure loss becomes large, and the stability of the sequence operation pressure from low flow rate to high flow rate cannot be obtained. Can not.

The present invention solves the above-mentioned problems of the prior art, and when the total force due to the pressure of one or both of the primary port and the secondary port is larger than the set force determined by the initial reaction force of the spring. A new flow path opening / closing valve that opens the flow path only to allow pressure oil flow between the primary side and the secondary side, and using it to boost the pressure on the load side from the minimum operating pressure of the variable pump. Another object of the present invention is to provide a hydraulic circuit capable of following the minimum operating pressure and reducing the pressure.

[0006]

According to a first aspect of the present invention, there is provided a poppet type bidirectional operation flow path opening / closing valve, which is seated in a seat opening between a first port and a second port provided in a body, and the two ports are provided. A poppet valve body for blocking communication between the poppet valve body and a spring for urging the poppet valve body in a seating direction in a spring chamber formed in the body, wherein the spring chamber communicates with a drain, and The poppet valve body is opposed to the spring force of the spring, and has a first pressure receiving area portion that is acted on by the pressure oil pressure on the first port side and a second pressure receiving area that is acted on by the pressure oil pressure on the second port side. And an area section. In this poppet valve body, the sum of the forces due to the pressure oil pressure on the first port side acting on the first pressure receiving area portion and the pressure oil pressure on the second port side acting on the second pressure receiving area portion is the spring. When the force is larger than the set force determined by the initial reaction force, the poppet valve element is separated from the seat to establish communication between both ports. That is, the poppet valve body has an effective pressure receiving area of the first pressure receiving area portion with respect to the pressure oil pressure P ₁ of A
₁ and A ₂ is an effective pressure receiving area for the pressure oil pressure P ₂ of the second pressure receiving area portion, A ₁ · P ₁ ≧ F _s or A ₂ · A against the preset initial reaction force F _{s of the} spring. When any of the conditions of P ₂ ≧ F _s is satisfied, the seat is separated from the seat to allow communication between both ports.

According to another aspect of the hydraulic circuit of the present invention, a variable pump for changing the discharge pressure and / or the discharge amount based on a control command by electric / hydraulic pilot valve control utilizing a part of the self-discharge pressure, and the variable pump. And a controlled actuator connected to the variable pump, and the poppet-type bidirectional operation flow path on-off valve interposed in the pressure oil supply flow path from the variable pump to the actuator. One of the first port and the second port is connected to the pump discharge port side, and the other is connected to the controlled actuator side.

In this case, the poppet valve body opposes the spring force of the spring and receives the pressure oil pressure P ₁ on the side of the first port and the first pressure receiving area portion and the pressure oil on the side of the second port. effective pressure-receiving area for said pressurized fluid pressure P ₁ of the second and a pressure receiving area portion and said first pressure receiving area of the poppet valve body with respect to the initial reaction force F _s of the spring acted upon by the pressure P ₂ It said poppet valve body is unseated when satisfying the condition of _{a 1 · P 1 + a 2} · P 2 ≧ F s is the effective pressure receiving area a ₂ a ₁ with respect to the hydraulic fluid pressure P ₂ of the second pressure receiving area portion And the initial reaction force F _s of the spring is F with respect to the minimum operating pressure P _{1S of the} variable pump.
It is set to _s = P _1S (A ₁ + A ₂ ).

A variable pump according to a third aspect of the present invention is a variable pump that changes discharge pressure and / or discharge amount based on a control command by electric / hydraulic pilot valve control utilizing a part of self-discharge pressure. The poppet-type bidirectional operation flow path opening / closing valve inserted in series to the discharge port is mounted.

Also in this case, the poppet valve body opposes the spring force of the spring and receives the pressure oil pressure P ₁ on the side of the first port and the pressure receiving area on the side of the first port and the pressure oil on the side of the second port. effective pressure-receiving area for said pressurized fluid pressure P ₁ of the second and a pressure receiving area portion and said first pressure receiving area of the poppet valve body with respect to the initial reaction force F _s of the spring acted upon by the pressure P ₂ It said poppet valve body is unseated when satisfying the condition of _{a 1 · P 1 + a 2} · P 2 ≧ F s is the effective pressure receiving area a ₂ a ₁ with respect to the hydraulic fluid pressure P ₂ of the second pressure receiving area portion And the initial reaction force F _s of the spring is F with respect to the minimum operating pressure P _{1S of the} variable pump.
It is set to _s = P _1S (A ₁ + A ₂ ).

[0011]

The operation of the poppet type bidirectional operation flow path opening / closing valve of the present invention is as follows.
The flow passage is opened only when the total force due to the pressure of one or both of the first port and the second port is larger than the set force determined by the initial reaction force of the spring, and the pressure oil flow between both ports is enabled. .. The poppet valve body has a pressure receiving area portion at its tip, and this pressure receiving area portion has a first pressure receiving area portion that is acted on by the pressure oil pressure P ₁ on the side of the first port and a pressure oil pressure on the side of the second port. And a _second pressure receiving area portion that receives the action of P ₂ . The poppet valve body is biased by a spring from its tail end side to be seated in the seat opening between both ports, and the spring chamber in which the spring is disposed preferably communicates with the drain through a proper throttle for shock absorption. To be done. The force generated in the poppet valve body when the pressure P ₁ on the first port side acts on the _first pressure receiving area portion, and the poppet valve when the pressure P ₂ on the second port side acts on the _second pressure receiving area portion. The force exerted on the body is a direction opposite to the spring force of the spring.

The effective pressure receiving area of the _first pressure receiving area portion, which is affected by the pressure oil pressure P ₁ on the first port side with respect to the pressure oil pressure P _1, is A ₁ , and the action of the pressure oil pressure P ₂ on the second port side is Assuming that the effective pressure receiving area for the pressure oil pressure P ₂ of the second pressure receiving area portion that receives the pressure is A ₂ , P ₁ or P ₂ is A ₁ · P with respect to the preset initial reaction force F _{s of the} spring. _The poppet valve element separates and communicates between both ports even when either condition of ₁ ≧ F _s or A ₂ · P ₂ ≧ F _s is satisfied. In this case, by making A ₁ and A ₂ different, the valve opening set pressure only by the pressure P ₂ on the second port side and the valve opening set pressure only by the pressure P ₁ on the first port side are different values. Can be set to.

Now, the discharge pressure and / or the discharge amount of this two-port type poppet type bidirectional operation flow passage opening / closing valve is changed based on a control command by electric / hydraulic pilot valve control utilizing a part of the self-discharge pressure. Consider a case where the first port is connected to the discharge port side of the variable pump and the second port is connected to the controlled actuator side in the hydraulic circuit interposed in the pressure oil supply flow path from the variable pump to the controlled actuator ( (Fig. 2).

In this case, the initial reaction force F _s of the spring is a force generated in the poppet valve body when the minimum operating pressure P _1S of the variable pump acts on both the first pressure receiving area portion and the second pressure receiving area portion. Is set to F _s = P _1S (A ₁ + A ₂ ), and the valve opening condition of the poppet valve is A ₁ · P ₁ + A ₂ · P ₂
≧ F _s . Here, for example, by setting A ₁ / A ₂ > 1 (preferably 2 to 4), the valve opening force by only the pressure P ₂ on the second port side is set by the first port by setting the initial reaction force F _s of the spring. It may be set to be slightly larger than the valve opening force due to only the side pressure P ₁ .

In the pressure control state, when the pressure P ₁ (and hence P ₂ ) is higher than the pump minimum operating pressure P _1S , the condition P ₁ (A ₁ + A ₂ )> F _S is satisfied and the poppet valve When the body is separated from the seat opening and the pressure oil supply flow path is opened, the pressure control of the actuator can be performed by the pressure that follows the pressure increase pattern of the pump discharge pressure.

When the pressure P ₂ on the second port side becomes lower than the pump minimum operating pressure P _1S and becomes P _2L , P _1S · A ₁ + P _2L · A
_{Since 2} <F _S , the poppet valve body is seated in the seat opening and the pressure oil supply flow path is closed, so pressure control on the actuator side by the pump becomes impossible, but this state is below the minimum operating pressure. Since there is no problem, there is no problem.

In this way, it is possible to change the pressure on the actuator side with good responsiveness in the range from the minimum operating pressure to the maximum pressure of the variable pump, following the pump pressure rising / lowering pattern.

On the other hand, in the flow rate control, in the variable pump of the self-pressure control system, the pump alone cannot control when the load pressure P ₂ on the actuator side is lower than the pump minimum operating pressure P _1S. When the poppet-type bidirectional operation flow path opening / closing valve of the present invention is inserted in the discharge line, the opening condition of this flow path opening / closing valve is A ₁ · P.
_{Since 1} + A ₂ · P ₂ ≧ F _s and the initial reaction force is set to F _s = P _1S (A ₁ + A ₂ ) by the spring force setting of the spring, the outlet pressure of the pump P ₁ is P ₁ ≧ P
_{1S + (A 2 / A 1} ) · (P 1S -P 2) , and the therefore, the load pressure P ₂ is the pump of the actuator side minimum working pressure P is lower than the _1S in the formula of P ₁ (P _1S - P ₂ ) is always a positive value, and eventually P ₁ is always larger than P _1S .

That is, by connecting the poppet type bidirectional operation flow path on-off valve, the outlet pressure P _{1 of the} pump becomes larger than the minimum operating pressure P _1S when the on-off valve is open, so that the flow rate can be controlled. It is possible.

According to the present invention, the variable pump equipped with the poppet-type bidirectional flow passage opening / closing valve uses a conventional sequence valve or a check valve or a sequence valve with a reverse direction check valve for supplying pressure oil to the actuator. No need to insert in series in the path.

Further, in the present invention, the spring chamber in which the spring for urging the poppet valve element in the seating direction is arranged is always connected to the drain and dropped to the tank line of the used circuit. It is preferable to place a suitable throttle in the flow path leading from this spring chamber to the drain in order to prevent movement and to make it shockless, and furthermore to arrange said spring in this spring chamber, for example of the screw type. It is also within the scope of the present invention to provide a pressure-adjustable structure.

The poppet-type bidirectional operation flow path on-off valve according to the present invention has a check for preventing free fall of cylinder load or leading run, in addition to being applied to the discharge line of a self-pressure control type variable pump. It can also be used instead of a counterbalance valve.

[0023]

FIG. 1 is a sectional view showing the structure of a poppet-type bidirectional operation flow path opening / closing valve according to an embodiment of the present invention, and FIG. 2 is a schematic view showing the dimensional relationship of the essential parts thereof. Further, FIG. 3 shows an embodiment of a hydraulic circuit in which this flow path opening / closing valve is connected to a pressure oil supply line. In FIG. 1, a valve body 10 is provided with a first port 1 and a second port 2, and a valve seat opening 3 is provided coaxially with the first port in the middle of an orthogonal internal passage communicating with them. A poppet valve body 4 is coaxially arranged on the opposite side of the seat 3 from the first port 1, and the poppet valve body 4 is tailed by a spring 6 arranged in a spring chamber 5 in a body behind the poppet valve body 4. The seat 3 is seated so as to close the seat 3 at the tip end by being pressed and urged from the end side, and moves against the spring 6 by the action of pressure oil from one or both of the first port 1 and the second port 2. By doing so, it is possible to open the flow path cutoff by the sheet 3.

The tip of the poppet valve body 4 is tapered so that it comes into seat contact with the seat 3 in the middle of the slope, and the opening area of the seat 3 is A, as shown in FIGS. Assuming that the cross-sectional area of the valve body is B, as shown in FIG. 2 (b), the portion of the area A viewed from the tip side of the poppet valve body 4 receives the action of the pressure oil pressure P ₁ on the first port 1 side. The first pressure receiving area portion (A ₁ ) constitutes the _first pressure receiving area portion (A ₁ ), and the portion having the area B-A similarly constitutes the second pressure receiving area portion (A ₂ ) which receives the action of the pressure oil pressure P ₂ on the second port 2 side. ing.

A spring chamber 5 in which a spring 6 for urging the poppet valve body 4 from the tail end side thereof is disposed is communicated with a drain port 7 connected to an external tank line. An appropriate throttle 8 for cushioning the hydraulic shock is provided. Although the end plug 9 that closes the spring chamber 5 is a plug screw in this embodiment, a screw mechanism for adjusting the pressure of the spring 6 may be incorporated therein.

Here, the force generated in the poppet valve body 4 when the pressure P ₁ on the side of the first port 1 acts on the first pressure receiving area portion of the poppet valve body 4, and the second pressure receiving area portion has the second force. the forces occurring poppet 4 when the pressure P ₂ of port 2 side acts, an orientation Tawameru together against the spring 6 to the spring force.

[0027] A ₁ effective pressure receiving area for said pressurized fluid pressure P ₁ of the first pressure receiving area portion subjected to the action of the pressure oil pressure P ₁ of the first port 1 side, the pressure oil pressure in the second port 2 side P ₂ Assuming that the effective pressure receiving area of the second pressure receiving area portion against the pressure oil pressure P ₂ is A ₂ , P ₁ or P _{2 of} the poppet valve body 4 is A with respect to the initial reaction force F _{s of the} spring 6. ₁ · P ₁ ≧ F
_s or A ₂ · P ₂ ≧ F _s is satisfied, the seat 3 is separated from the seat 3 to communicate between the ports.

In FIG. 3, the poppet type bidirectional operation flow path on-off valve is shown by a hydraulic symbol 11. In FIG. 3, the variable pump 12 is a self-pressure control type that utilizes a part of its own discharge pressure, and is based on a control command signal by a closed-loop feedback type electric / hydraulic pilot valve control by a detection signal of the discharge pressure and the flow rate. The discharge pressure and / or the discharge amount are changed according to the above method. A variable pump of such a type is already known, and the details thereof are described in, for example, Japanese Patent Application Laid-Open No. 62-55484 by the applicant, and therefore will not be described in detail here.

In FIG. 3, a poppet type bidirectional operation flow path on-off valve 11 is connected to the discharge port of the variable pump 12 by its first port 1, and its second port 2 is a directional valve 13.
It is connected to the actuator cylinder 14 via. The return port of the directional control valve 13 is connected to the tank line, and switching of the directional control valve 13 causes the cylinder 14
The operating direction of is switched.

In this hydraulic circuit, the poppet type bidirectional operation flow path on-off valve 11 may be incorporated in the variable pump 12, for example, in the housing cover, or may be externally mounted in the pump housing.

Now, the minimum working pressure P _{1S of} the self-pressure controlled variable pump 12 is applied to both the first pressure receiving area portion (A ₁ ) and the second pressure receiving area portion (A ₂ ) of the flow passage opening / closing valve 11 described above. Assuming that the spring force F _S is set to the load when acting, in FIG. 2, the variable pump 12 has a desired step-up / step-down pattern according to the command signal within the range between the minimum operating pressure and the maximum pressure. When sending the discharge pressure oil to the actuator 14, when the pressure P ₂ on the second port side is zero at the beginning, the condition for opening the flow passage opening / closing valve 11 is A ₁ · P ₁ ≧ F _s = P _1S (A ₁ + A ₂ ), P ₁ ≧ P _1S (1 + A ₂ / A ₁ ). Where A ₁ / A ₂
2 to 4, the pressure P of the first port 1 when the valve is opened
The ₁ is required pressure 25-50% higher than the pump minimum operating pressure P _1S, but pressure P _1S at least the second port 2 side when the flow channel opening and closing valve 11 is once you once opened is Since it is present, the flow path on-off valve 11 is kept open thereafter, and therefore the pressure on the actuator cylinder 14 side is
It is possible to control the desired pressure rising / falling pattern in the range of the minimum operating pressure to the maximum pressure in synchronization with the change in the pump discharge pressure.

[0032]

As described above, according to the present invention,
Only when the total force due to the pressure of one or both of the primary port and secondary port is larger than the set force determined by the initial reaction force of the spring, the flow passage is opened to allow pressure oil flow between the primary side and the secondary side. It is possible to obtain a poppet-type two-way flow path on-off valve, and to use it to increase the pressure on the load side from the minimum operating pressure of the variable pump and to follow it down to the minimum operating pressure. It is possible to provide a hydraulic circuit, and in particular, a self-pressure that changes the discharge pressure and / or the discharge amount based on the control command signal by the closed loop feedback type electric / hydraulic pilot valve control by the detection signal of the discharge pressure and the flow rate of itself. When using a control type variable pump, the load pressure can be stably reduced to the pump minimum operating pressure, and even when the load pressure falls below the pump minimum operating pressure. In which it is possible to perform an amount control.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a poppet type bidirectional operation flow path opening / closing valve according to an embodiment of the present invention.

2 is a schematic view showing a dimensional relationship of a main part of the flow passage opening / closing valve of FIG. 1, a is a schematic longitudinal sectional view, and b is a schematic end view of the poppet valve body as seen from the front end surface side.

FIG. 3 is a circuit diagram showing an embodiment of a hydraulic circuit in which a poppet-type bidirectional operation flow path opening / closing valve according to an embodiment of the present invention is connected in a pressure oil supply line.

[Explanation of symbols]

 1: 1st port 2: 2nd port 3: Valve seat opening 4: Poppet valve body 5: Spring chamber 6: Spring 7: Drain port 8: Throttling 9: End plug 10: Valve body 11: Poppet type bidirectional passage opening / closing Valve 12: Variable pump 13: Directional switching valve 14: Actuator cylinder

Claims (3)

[Claims] 1. A poppet valve body, which is seated in a seat opening between a first port and a second port provided in a body and blocks communication between the ports, and a spring chamber formed in the body. A spring for urging the poppet valve element in the seating direction, the spring chamber is communicated with a drain, and the poppet valve element opposes the spring force of the spring to act on the first port side pressure oil pressure. A first pressure receiving area portion that receives the pressure oil pressure and a second pressure receiving area portion that receives the pressure oil pressure on the second port side, and the first port side pressure oil pressure that acts on the first pressure receiving area portion and When the sum of the forces exerted on the second pressure receiving area portion by the pressure oil pressure on the second port side is larger than the set force determined by the initial reaction force of the spring, the poppet valve body separates from the two ports. Characterized by being configured to communicate Poppet type bidirectional operation flow path on-off valve. 2. A variable pump for changing discharge pressure and / or discharge amount based on a control command by electric / hydraulic pilot valve control utilizing a part of self-discharge pressure, and a controlled actuator connected to this variable pump. And a poppet-type bidirectional operation flow path opening / closing valve interposed in a pressure oil supply flow path from the variable pump to the actuator, the flow path opening / closing valve being a first port and a second port provided in the body. A poppet valve element that is seated in a seat opening between the port and blocks communication between the ports; and a spring that biases the poppet valve element in a seating direction in a spring chamber formed in the body, The spring chamber communicates with the drain, and the poppet valve body opposes the spring force of the spring to receive the pressure oil pressure P ₁ of the first port side and the first pressure receiving area portion and the second port side. Hydraulic pressure And a second pressure receiving area portion subjected to the action of P _2, the effective pressure receiving area to receive the hydraulic fluid pressure P ₁ of the initial reaction force F _s of the first pressure receiving area of the poppet valve body spring A ₁ And the effective pressure receiving area A ₂ with respect to the pressure oil pressure P ₂ of the second pressure receiving area portion are A ₁ · P ₁ + A ₂ · P ₂
When the condition of ≧ F _s is satisfied, the poppet valve element is separated so that both ports communicate with each other, and the initial reaction force F _{s of the} spring with _respect to the minimum operating pressure P _{1S of the} variable pump. _Is set to F _s = P _1S (A ₁ + A ₂ ). 3. A variable pump that changes the discharge pressure and / or the discharge amount based on a control command by electric / hydraulic pilot valve control that uses a part of the self-discharge pressure, and is inserted in series at the pump discharge port. First equipped with a poppet type bidirectional operation flow path opening / closing valve, and the flow path opening / closing valve is provided in the body
A poppet valve element which is seated in a seat opening between the port and the second port and blocks communication between the two ports, and a spring which biases the poppet valve element in a seating direction in a spring chamber formed in the body. And a first pressure-receiving area portion in which the spring chamber is communicated with a drain, the poppet valve body faces the spring force of the spring, and receives the action of the pressure oil pressure P ₁ on the side of the first port; A second pressure receiving area portion that receives the action of the pressure oil pressure P ₂ on the second port side, and the initial reaction force F of the spring is provided.
_With respect to _s , the effective pressure receiving area A ₁ for the pressure oil pressure P ₁ of the first pressure receiving area portion of the poppet valve and the effective pressure receiving area A ₂ for the pressure oil pressure P ₂ of the second pressure receiving area portion are A _{When the condition of 1} · P ₁ + A ₂ · P ₂ ≧ F _s is satisfied, it is determined that the poppet valve body is separated and the two ports communicate with each other, and the initial reaction force F _{s of the} spring is variable. A variable pump characterized in that F _s = P _1S (A ₁ + A ₂ ) is set for the minimum operating pressure P _1S of the pump.