JPH07180781A - Pilot operation type pressure control valve - Google Patents

Abstract

PURPOSE:To dissolve a time difference so as to carry out control uniformly in entively same operating conditions by providing a flow regulating mechanism for regulating the flow of a pilot fluid by manual operation to the series type flow regulating valve for supplying a constant pilot fluid to a pilot valve. CONSTITUTION:A relief valve 14 is formed by exchangeably assembling a valve body 15, a valve cylinder 16 and a spring 17 onto the abutting surfaces of first and second cabinets 1, 2, and a proportional electromagnetic type pilot valve 30 and a series shaped flow regulating valve 40 are provided in the second cabinet 2. The flow regulating valve 40 is operated so as to maintain a pressure difference between both sides of orifice 46 at a constant level at all times, and input pressure into the orifice 46 is controlled to a pressure obtained by adding a summation value determined by the spring constant of a summation spring 43 to set pressure. In this case, a regulating screw 61 for flow regulation provided on the flow regulating valve 40. The regulating screw 61 is subjected to advance/retreat by screwing motion, the spring constant of the summation spring 43 is changed so as to minutely regulate the output flow of the pilot fluid of the flow regulating valve 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot operated pressure control valve, and more particularly to a pilot solenoid type pressure control valve which is manually adjusted by a flow rate adjusting mechanism to supply pilot fluid from the flow rate adjusting valve to a proportional electromagnetic pressure control valve. The present invention relates to a pilot operated pressure control valve for controlling a high pressure main circuit fluid by opening and closing a valve such as a relief valve having an area ratio with a pilot fluid output from the proportional electromagnetic pressure control valve.

[0002]

2. Description of the Related Art The applicant previously applied for Japanese Patent Application No. 4-342566 as a pressure control valve of this type. Japanese Patent Application No. 4-3
A block diagram and a fluid circuit diagram of the pressure control valve of the invention No. 42566 are shown in FIG. 4 and FIG. 4 and 5, 1
1 is an inflow port, 12 is a return port, 13 is a drain port, and 14 is a relief valve. Reference numeral 15 is a valve element having upper and lower pressure receiving surfaces with an area ratio of K: 1, 16 is a valve cylinder, and 17 is a spring.
Reference numeral 20 is a series type flow control valve, and 30 is an electromagnetic pilot valve. 38 is a proportional solenoid of the pilot valve 30, 39 is an amateur. Further, r1 and r2 are throttles, Lm is a main circuit fluid, Lp is a pilot fluid, and D and T
Is the drain and return tank.

In the prior application device having such a structure, a part of the main circuit fluid Lm is guided to the series type flow control valve 20 and a constant pilot fluid Lp is supplied to the pilot valve 30 and the like. In the normal state, all the valves such as the relief valve 14 are in the positions shown in the figure and the equilibrium state is maintained. When the pressure of the main circuit fluid Lm rises, a flow is generated in the pilot fluid Lp, a differential pressure is generated before and after the throttle r1, and the pressure pushing the valve body 15 of the relief valve 14 downward becomes weak.

When the pressure of the main circuit fluid Lm exceeds a certain pressure, the balance of the relief valve 14 is lost, the valve element 15 moves upward, the valve seat 18 is opened, and the main circuit fluid Lm flows into the return T. After that, the pressure of the main circuit fluid Lm is reduced and the pushing force of the pilot fluid Lp is reduced, and the valve seat is closed again. The opening / closing operation of the relief valve 14 corresponding to the input current of the pilot valve 30 controls the main circuit fluid Lm to a pressure K times the pilot fluid Lp.

[0005]

In the pressure control valve of this type, as described above, the pilot fluid Lp of a constant flow rate is constantly supplied to the pilot flow passage by the series type flow rate adjusting valve 20. On the other hand, the orifice diaphragm r1
, R2, the spring 17, etc. are machined with a tolerance within a predetermined range. For this reason, a dimensional difference occurs between the completed completed parts, which causes a machine difference even in assembled devices of the same model, resulting in the pilot fluid L.
Variations will occur in the flow rate and pressure of p.

If there is a difference in the flow rate of the pilot fluid Lp supplied due to a machine difference and the flow rate is less than the reference amount to some extent, the response becomes slower. Further, when the flow rate increases above a certain level, there is a problem that the minimum pressure becomes high and the vibration becomes oscillating.

The present invention has been made in order to solve such a problem of the prior application device, and is provided with a flow rate adjusting mechanism capable of finely adjusting the flow rate of the pilot fluid manually. It is an object of the present invention to realize a pilot operated pressure control valve capable of controlling the pressure of the high-pressure main circuit fluid Lm by eliminating the difference in the flow rates of the above and supplying a uniform pilot fluid.

[0008]

SUMMARY OF THE INVENTION The present invention provides an electromagnetic pilot valve for controlling pilot fluid according to an input current of a solenoid, and a series type flow control valve for supplying a constant pilot fluid to the pilot valve. In a pilot operated pressure control valve equipped with a pressure control valve for controlling a high pressure main circuit fluid by opening and closing a valve body having an area ratio on the pressure receiving surface of the pilot fluid and the main circuit fluid, This is a pilot operated pressure control valve in which a flow rate adjusting mechanism for manually adjusting the flow rate of the pilot fluid is provided in the adjusting valve.

Further, the pilot operated pressure control valve for changing the spring pressure of the spring applied to the spool of the flow rate adjusting mechanism is constituted. In addition, a pilot operated pressure control valve that changes the throttle opening of the pilot fluid of the flow rate adjusting mechanism is configured. Further, the throttle opening is configured as a pilot operated pressure control valve that changes the cross-sectional area of the V-cut throttle.

[0010]

The pilot fluid, which is the set pressure of the pilot valve, is supplied to the pressurizing chamber of the relief valve through the pilot flow passage which is connected to the output side of the series type flow control valve and which is provided with a throttle. In a normal state, the poppet of the pilot valve closes the seat hole, the spool of the flow rate adjusting valve remains at a fixed position in the sleeve, and the valve seat of the relief valve is closed to maintain the equilibrium state.

When the pressure of the main circuit fluid increases, the pressure of the pilot fluid also rises, and a differential pressure is generated before and after the throttle provided in the pilot flow passage added to the relief valve, and the pressure of the pilot fluid that pushes the relief valve is increased. Weakened. Further, when the pressure of the main circuit fluid rises and exceeds the set pressure, the valve body of the relief valve moves, the valve seat is opened, and the main circuit fluid flows out to the return side.

After that, when the pressure decreases due to the outflow of the main circuit fluid, the pressure of the pilot fluid also decreases and the valve seat is closed again. Thus, the relief valve operates so that the maximum pressure of the main circuit fluid is controlled so as not to exceed the set pressure. Since the pressure receiving surface on the pilot fluid side of the valve body of the relief valve is made K times as high as the pressure receiving surface of the main circuit fluid, the pressure of the main circuit fluid having K times high pressure is controlled.

In the present invention, a series type flow rate adjusting valve is provided with a flow rate adjusting mechanism for adjusting the output flow rate. The flow rate adjusting mechanism is provided with a structure for adjusting the spring pressure of a spring that presses the spool with an adjusting screw and a variable throttle provided at the output end of the flow rate adjusting valve. By adjusting the adjusting screw and variable throttle of the flow rate adjusting mechanism, variations in the output flow rate due to machine differences are corrected. Then, for example, a systematic hydraulic circuit in which the same model is connected in parallel can be uniformly controlled by the same operation.

[0014]

【Example】

Embodiment 1 FIG. 1 is a configuration explanatory view of an embodiment of the present invention. In the embodiment of the present invention, the same parts as those of the prior application device are denoted by the same reference numerals, and the description will be partially duplicated but will be described in a little more detail.

In FIG. 1, 1 is a first housing, 2 is a second housing, 3 is a third housing, and Lm and Lp are the same main circuit fluid and pilot fluid as described above. Reference numerals 11 and 12 denote inlets and return ports for the main circuit fluid Lm provided in the first housing 1, 13 denotes a drain port for the pilot fluid Lp, and 14 denotes a relief valve.
The relief valve 14 is composed of a valve body 15, a valve cylinder 16 and a spring 17 which are assembled in the first housing 1 in a cartridge type. Reference numeral 18 is a valve seat of the relief valve 14, and 19 is a pressurizing chamber formed on the upper surface side of the valve body 15.

The valve body 15 of the relief valve 14 is formed in a substantially T-shape, and is interposed with a spring 17 in a sliding hole of the same shape formed at the center of the valve cylinder 16 so as to be vertically slidable. There is. The pressure receiving surface Fp on the upper surface side of the valve body 15 is made K times as large as the pressure receiving surface Fm on the lower surface side. Further, the lateral pressure surface Fs is formed in (K-1) and communicated with the drain port 13. Then, the pilot fluid Lp added to the pressurizing chamber 19
Thus, high pressure control of the main circuit fluid Lm introduced into the inlet 11 is possible.

Reference numeral 30 is a proportional electromagnetic pilot valve.
Reference numeral 31 is a seat, 32 is a seat hole, 33 is a conical poppet, 34a is a balance spring, 34b is a return spring, and 35 is a push rod. 36 is an input chamber outside the seat 31;
37 is a poppet 33, a balance spring 34a, and a return spring 34.
This is the drain room where b is located. Reference numeral 38 is a proportional solenoid provided in the third housing 3.

Reference numeral 40 is a series type flow rate adjusting valve. Four
Reference numeral 1 is a sleeve of the flow rate adjusting valve 40, 42 is a spool that slides in the sleeve 41, and 43 is an addition spring. 44 and 4
Reference numeral 5 is an inflow groove and outflow groove provided in the sleeve 41, 46 is an orifice, 47 is a side passage, and 48 is an internal passage of the spool 42. The outflow groove 45 is connected to the input chamber 36 of the pilot valve 30. Further, the hole diameter of the internal flow passage 48 is formed to be slightly larger than the orifice 46 and the side passage 47. 49 is a pressure receiving chamber formed on the right side in the sliding hole of the spool 42, 51 is a cylindrical flow passage formed in the central portion, and 52 is a spring chamber in which the addition spring 43 is arranged.

The pressure receiving chamber 49 is connected to the flow passage 51 through the internal flow passage 48, and the spring chamber 52 is connected to the side passage 47 and the orifice 4.
It communicates with the flow path 51 via 6. That is, the input pressure of the pilot fluid Lp to the orifice 46 is the internal flow path 48.
Is applied to the pressure receiving chamber 49 via the side passage 47, and the output pressure is guided to the spring chamber 52 via the side passage 47. The series type flow control valve 40 operates so that the pressure on both sides of the orifice 46 is always constant, compensating for the pressure fluctuation of the pilot fluid Lp and the input pressure to the orifice 46 with respect to the set pressure Ps. The pressure is controlled so that an added value determined by the spring constant of the adding spring 43 is added.

Reference numeral 61 is an adjusting screw for adjusting the flow rate, and 62 is a fixing nut screwed into the exposed portion of the male screw 63 of the adjusting screw 62. The middle of the adjusting screw 61 is screwed into a female screw 64 which is screwed through the second housing 2 and the tip of the adjusting screw 61 has a spring chamber 5
It faces the inside of 2 and is pressed against the addition spring 43. Then, the flow rate adjusting mechanism 60 is configured by the adjusting screw 61 and the nut 62, and the output flow rate of the pilot fluid Lp of the flow rate adjusting valve 40 is finely adjusted manually by screwing the adjusting screw 61 from the outside.

Reference numeral p is a pilot flow passage through which the pilot fluid Lp flows, d is a drain flow passage through which the drain Ld flows, and r is a throttle. A part of the main circuit fluid Lm flows into the flow rate adjusting valve 40 via the flow path opened to the inlet 11. D and T are tanks for storing drain and return, and are designated by the same reference numerals as those of the above-mentioned prior application device.

The operation of the embodiment of the present invention having the above construction will be described below. As shown in the drawing, the pressurizing chamber 19 of the relief valve 14 has an outflow groove 45 of the series type flow control valve 40.
A pilot fluid Lp is supplied through a pilot flow path p which is connected to and is provided with a restriction r. The pilot fluid Lp is supplied to the input chamber 36 of the pilot valve 30 through the pilot flow path p branched from the outflow groove 45. In the normal state, the poppet 33 of the pilot valve 30 closes the seat hole 32, and the relative positional relationship between the spool 42 of the flow rate adjusting valve 40 and the sleeve 41 is in the state shown in the figure, and the valve seat of the relief valve 14 is in the state. 18 is closed and equilibrium is maintained.

Here, when the pressure of the main circuit fluid Lm increases, a part of the raised main circuit fluid Lm flows into the flow passage 51 through the inflow groove 44 of the series type flow control valve 40. The main circuit fluid Lm that has flowed into the flow passage 51 also flows into the pressure receiving chamber 49 through the internal flow path 48 as it is. At this time, a differential pressure is generated before and after the orifice 46 in the sleeve 41, and the pressure on the spring chamber 52 side becomes lower than the pressure on the pressure receiving chamber 49 side. Therefore, when the spool 42 is pushed to the left and reaches a certain position, the inflow groove 44 is closed and the inflow of the main circuit fluid Lm is blocked. In this way, a fixed amount of pilot fluid Lp is supplied to the pilot valve 30.

When the pressure of the pilot fluid Lp rises to reach the set pressure Ps, the poppet 33 of the pilot valve 30 is pushed and the seat hole 32 is opened. At the same time, the balance of the relief valve 14 is lost, the valve body 15 moves upward, and the valve seat 18 is opened. When the valve seat 18 of the relief valve 14 is opened and the main circuit fluid Lm flows into the return tank T,
The pressure of the main circuit fluid Lm decreases. After that, the inlet 11
The pressure of the main circuit fluid Lm introduced from the side surface of the valve also decreases, and the valve seat 18 is closed again.

In this way, the relief valve 14 operates so that the maximum pressure of the main circuit fluid Lm does not exceed the set pressure Pm, and the safety of the hydraulic equipment connected to the load side is maintained. When the pressure of the main circuit fluid Lm is made higher, the input current of the proportional solenoid 38 can be increased so as to correspond to this pressure, and the pressure can be similarly controlled.

Particularly, the pressure receiving surface Fp on the upper side of the valve body 15 of the relief valve 14 is made K times as large as the pressure receiving surface Fm on the lower side. Then, the pressure of the pilot fluid Lp is applied to the pressure receiving surface Fp of the valve body 15 facing the pressurizing chamber 19, the fluid pressure of the main circuit fluid Lm is applied to the lower pressure receiving surface Fm, and the side pressure surface is the drain port. It is configured to communicate with 13. As a result, a pilot-operated pressure control valve that can control the main circuit fluid Lm that is K times higher in pressure is constructed regardless of the use of a pilot valve having a thrust and rating comparable to those of the prior application device. For example, high pressure control of about 100 MPa (Mega-Pascal) becomes possible by using a standard proportional electromagnetic pilot pressure control valve.

On the other hand, as described above, the diameter of the orifice 46 of the series type flow rate adjusting valve 40, the spring constant of the addition spring 43, etc. are manufactured to have different values within an allowable range depending on the model. Therefore, the output flow rate of the pilot fluid Lp output from the series type flow control valve 40 varies.

In such a case, first, the nut 62 for fixing the flow rate adjusting mechanism 60 exposed to the outside of the second housing 2 is loosened, and the adjusting screw 61 is screwed. When the adjusting screw 61 is rotated clockwise, the adjusting screw 61 moves forward to compress the addition spring 43 and increase the spring pressure. On the contrary, when the adjusting screw 61 is rotated in the counterclockwise direction, the adjusting screw 61 is retracted and the adding spring 4 is moved.
3 will be expanded and the spring pressure will be weakened. By such fine adjustment of the flow rate adjusting mechanism 60, a uniform flow rate corresponding to the pressure change of the main circuit fluid Lm can be output, and the error of the output flow rate which differs depending on the model can be compensated. After adjusting the flow rate, the adjusting screw 61 is locked by the fixing nut 62.

Embodiment 2 FIG. 2 is a structural explanatory view of Embodiment 2 of the present invention, and FIG. 3 is an enlarged view of a sleeve of the flow rate adjusting mechanism in FIG. In the second embodiment of the present invention, the special adjusting screw 61 like the flow rate adjusting mechanism 60 of the first embodiment is not provided. Instead, as shown in FIGS. 3A and 3B, a male screw 63 is formed on the outer circumference of the sleeve 41, and the male screw 63 is screwed into the female screw 64 of the second housing 2. There is.

Reference numeral 65 is a variable diaphragm for adjustment, and 66 is an annular groove. The variable diaphragm 65 is provided in the sleeve 41, and the annular groove 66 is formed in the housing 2 so as to face the variable diaphragm 65. The variable throttle 65 and the annular groove 66 correspond to the orifice 46 and the outflow groove 45, respectively. This variable diaphragm 65 is a V-cut diaphragm (tr
iangular-notch). Then, when the fixing nut 62 is loosened and the spool 42 is rotated forward and backward, the sleeve 41 is screwed forward and backward. The relative position between the variable throttle 65 and the edge portion of the annular groove 66 is moved by the screwing of the sleeve 41, and the fan-shaped channel cross-sectional area is continuously changed.

As a result, as in the first embodiment, the output flow rate of the series type flow control valve 40 in the area a surrounded by the two-dot chain line in FIG. All equipment can be controlled under uniform operating conditions.

In the above embodiment, the valve body 15 is used as the valve cylinder 1.
The case where the pressure of the main circuit fluid Lm is maintained at a constant value or less by using the relief valve 14 for opening and closing 6 has been described as an example, but a balance piston type relief valve or a pressure reducing valve may be used. In the embodiment, the conical poppet 33 is used for the pilot valve 30, but a spherical poppet is used for the seat hole 3.
2 may be opened and closed. Further, although the description has been given of the case where the orifice of the sleeve of the flow rate adjusting valve is built in, the orifice may be provided in another portion.

[0033]

According to the present invention, an electromagnetic pilot valve for controlling a pilot fluid according to an input current of a solenoid, a series type flow control valve for supplying a constant pilot fluid to the pilot valve, and a pilot fluid are provided. In a pilot-operated pressure control valve equipped with a pressure control valve that controls a high-pressure main circuit fluid by opening and closing a valve element that has an area ratio on the pressure receiving surface with the main circuit fluid by a pilot valve, manually operate the flow control valve. The pilot-operated pressure control valve was equipped with a flow rate adjustment mechanism that adjusts the flow rate of the pilot fluid.

Further, a pilot operated pressure control valve for changing the spring pressure of the spring applied to the spool of the flow rate adjusting mechanism is constructed. In addition, a pilot operated pressure control valve that changes the throttle opening of the pilot fluid of the flow rate adjustment mechanism was constructed. Further, a pilot operated pressure control valve in which the throttle opening changes the cross-sectional area of the V-cut throttle is constructed.

As a result, even if the output flow rate of the pilot fluid Lp of the flow rate adjusting valve varies due to the machine difference between the same models, the flow rate adjusting mechanism supplies a uniform pilot fluid regardless of the machine difference, and the high pressure. It is possible to control the main circuit fluid Lm. Therefore, the pilot fluid L
There is no difference in the supply flow rate of p and the response is not delayed, and the increase in flow rate does not cause the valve to vibrate.
Further, even if the discharge function of the pump is lowered or the line resistance is increased, the output flow rate of the flow rate adjusting valve can be adjusted by adjusting the flow rate adjusting mechanism so that it can be always maintained at a predetermined flow rate.

Therefore, according to the present invention, it is possible to provide a pilot operated pressure control valve which can be uniformly controlled under the same operating condition without any machine difference and which can control the high pressure of the main circuit fluid.

[Brief description of drawings]

FIG. 1 is a configuration explanatory diagram of a first embodiment of the present invention.

FIG. 2 is a structural explanatory diagram of Embodiment 2 of the present invention.

FIG. 3 is an enlarged view of a spool of the flow rate adjusting mechanism according to the second embodiment of the present invention.

FIG. 4 is a structural explanatory view of an electromagnetic pressure control valve of a prior application.

FIG. 5 is a fluid circuit diagram of the electromagnetic pressure control valve of the prior application.

[Explanation of symbols]

 14 Relief valve 16 Valve body 18 Valve seat 17 Spring 19 Pressurizing chamber 30 Pilot valve 38 Proportional solenoid 40 Flow rate adjustment valve 41 Sleeve 42 Spool 43 Addition spring 46 Orifice 47 Side passage 48 Internal flow passage 60 Flow rate adjustment mechanism 61 Adjustment screw 62 Fixed Nut 63 Male screw 64 Female screw 65 Adjustment variable throttle 66 Annular groove p Pilot channel d Return channel r Throttle Fm Pressure receiving surface Fp Pressure receiving surface Lm Main circuit fluid Lp Pilot fluid T Return tank D Drain tank

Claims (4)

[Claims] 1. An electromagnetic pilot valve for controlling a pilot fluid according to an input current of a solenoid, a series type flow control valve for supplying a constant pilot fluid to the pilot valve, the pilot fluid and a main circuit. In a pilot operated pressure control valve equipped with a pressure control valve for controlling a high pressure main circuit fluid by opening and closing a valve body having an area ratio on a pressure receiving surface with a fluid by the pilot valve, the flow control valve is manually operated. A pilot-operated pressure control valve characterized by being provided with a flow rate adjusting mechanism for adjusting the flow rate of the pilot fluid with. 2. The pilot operated pressure control valve according to claim 1, wherein the spring pressure of a spring applied to the spool of the flow rate adjusting mechanism is changed. 3. The pilot operated pressure control valve according to claim 1, wherein the throttle opening of the pilot fluid of the flow rate adjusting mechanism is changed. 4. The pilot operated pressure control valve according to claim 3, wherein the throttle opening is changed in cross-sectional area of the V-cut throttle.