JP2000009250A - Proportional throttle valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proportional throttle valve that stabilizes an associated system, keeps its own responsiveness intact, has a strong resistance to disturbances all for high precision and high efficiency, through positive utilization of its operating chamber, which includes a feedback spring and lies between the pilot spool of a three-way pilot valve and the main spool of a pilot-operated main valve, as a cooperative damping chamber via a resistance element. SOLUTION: The proportional throttle valve comprises an electromagnetic actuator, a three-way pilot valve having a pilot line Pp a control line Pa and a return line Dr2, a pilot-operated main valve in which at least pressures in a pressure line PLT and an operating chamber Py are opposite to each other, and a feedback spring 104 disposed in the operating chamber Py. Another pilot line 7 is laid from the pressure line PLT to the pilot line Pp, and the operating chamber Py and control line Pa are connected via a resistance element 8, so that the operating chamber Py serves as a cooperative damping chamber 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic proportional throttle valve used for a hydraulic device.

[0002]

2. Description of the Related Art Conventionally, as a proportional throttle valve of this type, for example, the one shown in FIG. 5 (document: Hydraulic and Pneumatic Handbook, Ohmsha, New Edition (1989), page 346, see FIG. 3 ・ 341)
It has been known. This proportional throttle valve includes a proportional electromagnet 101 as an electromagnetic actuator, a control path Pa and a return path Dr.
2 and a pressurization passage PL
The main pipeline entrance path P, the main pipeline exit path A, and the operation room P also serving as T
y, the pilot valve 102 has a main body 111 having a hole 109 and a groove 110, and the pilot valve 102 is slidably fitted in the hole 109. Insert and land 112, 113
Spool 105 having a rod groove 114
And a drain path D between the rod groove 114 and the main body 111.
r, the return path Dr2 and the communication path 116, the control path Pa connected to the groove 110, the operation chamber Py where the end surface of the pilot spool 105 is exposed, and the void 117 in the proportional electromagnet 101. And a throttle 107 interposed in a pilot path 108 which is an internal pilot type connecting the communication path 115 and the inlet path P. The main valve 103
Is slidably fitted into the hole 119 on the main body 111, the groove 118 having the tapered surface sheet 121 communicating with the entrance path P and the exit path A on the main body 111, and the hole 119. And a main spool 106 for partitioning the inlet path P, the outlet path A, and the operation chamber Py, and a main spring 120 in the operation chamber Py that comes into pressure contact with the main spool 106. And the feedback spring 10 is provided between the pilot spool 105 and the main spool 106.
4, and the push rod 122 of the proportional electromagnet 101 can abut the pilot spool 105.
The inlet path P is connected to a hydraulic power source via an external pipe (not shown), the outlet path A is connected to an external load (not shown), and the drain path Dr is connected to an external tank. When the proportional throttle valve is energized by the above configuration to excite the proportional electromagnet 101 and keep the current constant, an electromagnetic operating force substantially proportional to the current is generated in the push rod 122, and the pilot spool 105 is moved leftward to provide feedback. At the same time that the spring 104 is pressed, the control section between the control path Pa and the return path Dr2 is opened to reduce the pressure in the operation chamber Py, thereby causing a pilot flow in the throttle 107, and the working fluid in the inlet path P. Part of pilot valve 1
02 to the drain path Dr side, the main spool 106 is moved rightward by the pressure difference generated in the throttle 107, the feedback spring 104 is pushed back, and the main control unit between the sheet 121 and the main spool 106 is opened. Thus, the working fluid of the hydraulic power source is supplied from the inlet passage P to the outlet passage A. Here, when the pilot spool 105 is pushed back by the feedback spring 104 and moves rightward to narrow or close the control unit between the control path Pa and the return path Dr2, the pressure in the operation chamber Py is reduced. 1
07, the main spool 106 may move leftward under the pressure of the inlet path P to extend the feedback spring 104. In the above, the pressure of the control path Pa is acting on the vacant space 117, and the amount of oil flows in and out according to the movement of the pilot spool 105. As a result, the main spool 106 eventually comes to a standstill, and the opening of the main control unit corresponding to the current is obtained. However, regarding the relationship of the force acting on the pilot spool 105, a closed loop is formed through the displacement of the main spool 106. It is clear that the pilot flow through the throttle 107 when the system is in a balanced state and the main spool 106 is stationary is commensurate with the pressure difference acting on the throttle 107. On the other hand, it is apparent that a similar closed loop is formed when the current decreases, and the displacement of the main spool 106 is controlled in the same manner.

[0003]

However, in the above-mentioned conventional proportional throttle valve, the pilot flow passing through the throttle 107 always occurs as a drain amount during operation, which not only causes a loss but also the throttle 107 is of a fixed type. Fluctuations in the control pressure of the operation chamber Py with respect to the displacement of the pilot spool 105 are slow, and fluid disturbances due to the main flow acting on the main spool 106 and pressure disturbances acting on the main pipeline due to the lack of a complete static pressure balance structure of the main spool 106. And the control accuracy of the main spool 106 is problematic. Therefore, an object of the present invention is to add a pilot path Pp and transfer the function of the throttle 107 to the pilot spool to form a three-way pilot valve, and then to provide a feedback spring 104 between the pilot spool and the main spool. By including the operation room Py including the positively acting cooperative damping room 9 via the resistance element 8, the system is stabilized, the responsiveness is not impaired, and the disturbance is strengthened to maintain high accuracy. An object of the present invention is to provide a proportional throttle valve having high efficiency.

[0004]

In order to achieve the above object, the proportional throttle valve of the present invention basically has an analog electromagnetic actuator and a pilot path 108 having a throttle 107, as shown in FIG. A two-way pilot valve 10 having a control path Pa and a return path Dr2 connected with a branch
2, a pilot-operated main valve in which at least the pressure of the pressurizing path PLT and the pressure of the operation chamber Py are opposed to each other, and the pilot spool 102 of the pilot valve 102 and the main spool of the main valve. A proportional throttle valve comprising a feedback spring 104 in the operation room Py and having a closed loop therein;
02 is a three-way pilot valve 1 having a pilot path Pp, the control path Pa, and the return path Dr2, and the pilot path 1 extending from the pressurizing path PLT of the main valve.
08 is connected as a pilot path 7 to the pilot path Pp, and the operation room Py and the control path Pa are connected via a resistance element 8, so that the operation room Py is a cooperative damping chamber 9. . As shown in FIG. 1, the proportional throttle valve according to the present invention is configured such that the pilot pressure side of the pilot valve 1 exposed to the cooperating damping chamber 9 has a diameter larger than that of the pilot spool. The piston 10 is provided so as to be interposed between the feedback spring 104 and the pilot spool.

[0005]

In the above construction, when the analog type electromagnetic actuator is excited to keep the current constant, an electromagnetic operating force substantially proportional to the current acts on the pilot spool of the pilot valve 1 to move the pilot spool to the left, and the feedback spring Simultaneously, when the controller 104 is pressed, the controller between the pilot path Pp and the control path Pa is closed, and simultaneously, the controller between the control path Pa and the return path Dr2 is opened.
At the same time, the pressure of the cooperating damping chamber 9, which is the operation chamber Py, is released to the return path Dr2 through the resistance element 8, and the pressure of the pressure path PLT is reduced. The receiving main spool is moved to the right to push back the feedback spring 104, and the opening degree of the main control section spanning between the main lines of the pilot operated main valve is controlled to transfer the fluid of the hydraulic power source (not shown) to a load or the like (not shown). Supply. Here, when the oil drained from the cooperative damping chamber 9 provided by the pilot spool and the main spool passes through the resistance element 8, it simultaneously cooperates with both the pilot spool and the main spool to exhibit a damping effect. Further, suppose that the pilot spool is pushed back by the feedback spring 104 to open the control unit between the pilot path Pp and the control path Pa, and at the same time close the control unit between the control path Pa and the return path Dr2. , This time the cooperating damping chamber 9 is a resistance element 8
The supply pressure is increased by receiving the supply of the pilot fluid from the pilot path Pp through the
And the feedback spring 104 is extended by moving to the left against the pressure of. As a result, the main spool eventually comes to a standstill and obtains the opening of the main control unit corresponding to the current, but forms a closed loop through the displacement of the main spool in relation to the force acting on the pilot spool. Further, when the system is in a balanced state and the main spool is stationary, the pilot spool is almost at the neutral point, and the pilot flow to the return path Dr2 is only a small amount of drain.
On the other hand, when the current decreases from the stationary state, the pilot fluid is supplied from the pilot path Pp to the cooperative damping chamber 9 through the resistance element 8, so that the same cooperative damping effect is obtained and the same closed loop is formed. Then, the opening of the main control unit is controlled again. In this way, the operation chamber Py including the feedback spring 104 between the pilot spool and the main spool is positively set to the cooperative damping chamber 9 via the resistance element 8 after the pilot valve has a three-way configuration. Regarding the pressurizing path PLT, regardless of the internal pilot type and the external pilot type, the speeds of the pilot spool and the main spool in the closed loop can be appropriately offset, and the damping effect given to the system is very good, and the main flow acting on the main spool And the transient fluid force disturbance acting on the pilot spool as well as the control unit between the control path Pa and the return path Dr2 can be set to a high gain with a high pressure difference. Has a main spool that is stable, does not impair responsiveness, is strong against disturbance, and has a low static pressure balance. Even the opening of the main spool can be held with high accuracy, also it is possible to highly efficiently. Further, the diameter of the pilot spool side exposed to the cooperating damping chamber 9 is enlarged, the auxiliary piston 10 is inserted, and the pilot spool is made to be stepped, so that the cooperating damping effect is further increased and the control is performed. The performance is further improved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 shows a basic embodiment of a proportional throttle valve, which is a three-way pilot valve 1 having an analog electromagnetic actuator 101, a pilot path Pp, a control path Pa, and a return path Dr2. And the pressure path PL
A pilot-operated two-way main valve 2 having an inlet path P also serving as T, an outlet path A, and an operation chamber Py; a feedback spring 104;
The pilot valve 1 has a hole 11, an enlarged hole 21, and a groove 110 serving as the control path Pa, which is roughly constituted by a cooperating damping chamber 9 containing an auxiliary piston 10 and a resistance element 8 for accommodating the piston 04. The pilot body 6 and the lands 112, 12, and 13 and the rod groove 1
A pilot spool 3 having 14, 14, holes 30, 31, 32 and a communication path 33, and an auxiliary piston 10 having the resistance element 8 slidably fitted in the enlarged hole 21.
The pilot path Pp connecting the rod groove 14 and the entrance path P, and the pilot path 7 of the internal pilot type;
The return path Dr2 connecting the rod groove 114 and the drain path Dr, the communication path 116, and the space 11 connected to the control path Pa through the holes 30, 31 and the communication path 33.
7 and the main valve 2 is connected to the inlet passage P
The main valve body 5 has a small-diameter hole 15 connected to the outlet passage A, a large-diameter hole 16 connected to the outlet passage A, and the drain passage Dr, a small-diameter cylindrical portion 19, a large-diameter cylindrical portion 20, a hole 119, and holes 17, 18.
118 with tapered sheet 121 leading to
And the cartridge body 4 accommodated in the small-diameter hole 15 and the large-diameter hole 16, and slidably fitted in the hole 119 to enter the inlet path P, the outlet path A, and the operation chamber. P
and a main spring 120 in the operation chamber Py, which is attached to the main spool 106 while being in contact with the main spool 106 and received and mounted by the spring receiver 34. 2, the pilot valve 1 is fixed to the main valve 2 with bolts 22 and the main spring 120
The operation chamber Py is formed as the cooperating damping chamber 9, and the electromagnetic actuator 101 is fixed to the pilot valve 1 with bolts 23, and the push rod 122 of the electromagnetic actuator 101, the pilot spool 3, and the auxiliary The piston 10 and the feedback spring 104 are respectively brought into contact with each other, and the working fluid is sealed with O-rings shown in members 24 to 29. Each member 10
1, 104, 106, 110, 112, 114, 116
-122, P, A, Py, Pa, Dr2, and Dr are the same as those of the conventional example described with reference to FIG. 5, and the same members are denoted by the same reference numerals and description thereof will be omitted. The operation of the proportional throttle valve having the above configuration will be described below. When the electromagnetic actuator 101 is excited and the current is kept constant, an electromagnetic operating force substantially proportional to the current is generated on the push rod 122 to move the pilot spool 3 to the left and simultaneously press the feedback spring 104 via the auxiliary piston 10. Then, the control unit between the pilot path Pp and the control path Pa is closed, and at the same time, the control unit between the control path Pa and the return path Dr2 is opened so that the working fluid of the internal pilot type is supplied from the inlet path P to the pilot path Pp. At the same time, the pressure in the cooperating damping chamber 9 is released from the return path Dr2 to the drain path Dr through the resistance element 8, the hole 32, the communication path 33 and the hole 31, and the main spool 106 receiving the pressure in the inlet path P is moved to the right. To push back the feedback spring 104 and open the main controller between the inlet path P and the outlet path A to open the working fluid of the hydraulic power source (not shown). And supplies, such as in a load (not shown). Here, the oil drained from the cooperating damping chamber 9 provided by the auxiliary piston 10 and the main spool 106 passes through the resistance element 8, thereby canceling out both the speed of the pilot spool 3 and the speed of the main spool 106. To produce a damping effect that works together at the same time. The enlarged hole 21 and the pilot spool 3
Step Room and Void 117 Separated by Auxiliary Piston 10
The excess or shortage of the fluid which occurs at the same time is compensated through the holes 30, 31, 32 and the communication path 33 with substantially no resistance. Further, the pilot spool 3 is pushed back by the feedback spring 104 to open the control section between the pilot path Pp and the control path Pa, and at the same time closes the control section between the control path Pa and the return path Dr2. Then, the cooperating damping chamber 9 receives the supply of the pilot fluid from the pilot passage Pp through the resistance element 8 to increase the operating pressure, and moves the main spool 106 to the left against the pressure of the inlet passage P to feed back the feedback spring. Expand 104. Regarding the relationship between the forces acting on the pilot spool 3 in the above control operation, a closed loop is eventually formed through the displacement of the main spool 106, and the main spool 106 eventually comes to rest at a position corresponding to the current. Further, when the main spool 106 is controlled and stopped, the position of the pilot spool 3 is substantially at the neutral point, and the position of the movable core of the electromagnetic actuator 101 is also approximately の of the controllable effective stroke. Further, it is known that the flow of the pilot to the return path Dr2 when the main spool 106 is at rest is limited to a small drain amount. On the other hand, when the current decreases from the static pressure state, the pilot fluid is supplied from the pilot path Pp to the cooperating damping chamber 9 through the resistance element 8, so that the same cooperating damping effect is obtained and at the same time the same closing is performed. A loop is formed to control the opening of the main control unit again. In addition, if the numerical example is shown, the diameter of the auxiliary piston 10 is 1
4 When ^phi mm before and after the aperture diameter of the resistive element 8 to 2.5
It is about ^φ mm. As described above, after the pilot valve has a three-way configuration, the pilot spool 3 and the main spool 1
The operating room Py including the feedback spring 104 between the position 06 and the positively acting cooperative damping room 9 via the resistance element 8.
Therefore, the speeds of the pilot spool 3 and the main spool 106 in the closed loop can be appropriately offset, and the damping effect given to the system becomes extremely good, so that not only the fluid force disturbance acting on the main spool 106 but also the transient force acting on the pilot spool 3 Fluid force disturbance can be absorbed, and the control section between the control path Pa and the return path Dr2 can be made high gain with a high pressure difference. Therefore, the system is stable even under high pressure, and the response is not impaired. Therefore, even if the main valve has a main spool having no static pressure balance, the opening degree of the main spool can be maintained with high accuracy, and the system can be made highly efficient. Also, the diameter of the pilot spool 3 side exposed to the cooperating damping chamber 9 is increased,
Since the auxiliary piston 10 is inserted and the pilot spool 3 is made to be stepped, the cooperating damping effect is further increased, and the controllability is further improved. Also,
FIG. 2 shows another embodiment of the proportional throttle valve of the present invention.
This proportional throttle valve differs from FIG. 1 in that it uses a pilot spool 3 'having lands 35 and 36 and a pilot body 6' in which the arrangement of the pilot path Pp and the return path Dr2 is reversed. The same members as 1 are given the same reference numerals and description thereof is omitted. Needless to say, the same operation and effect as in FIG. Another embodiment of the present invention shown in FIG. 3 shows a main valve 2 'having a main spool having a low static pressure balance, and a cartridge body 4' has a groove 118 'connected to holes 17, 18'. Yes,
The main spool 106 'has a sheet 37 having a tapered surface.
The same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The sheet diameter of the main spool 106 'determined by the hole 18' is smaller than the diameter of the hole 119, and the control accuracy of the main spool 106 'is disturbed by the influence of the pressure in the inlet passage P and the outlet passage A, that is, the pressure disturbance acting on the main pipeline. However, due to the action of the closed loop through the three-way pilot valve 1, the disturbance, that is, the decrease in accuracy is suppressed to a smaller extent. Another embodiment of the present invention shown in FIG. 4 has an electromagnetic actuator 101, a cooperating damping chamber 9, a pilot spool 3 ", a resistance element 8 in the pilot spool 3" and a pilot body 6 ". The pilot valve 1 'and the cover 39 oppose the cooperating damping chamber 9.
A pilot operated four-way main valve 2 "having a pressurizing chamber 40, a main spool 106" and a main valve body 5 'therein.
And a feedback spring 104 in the operation room Py.
And a pressurizing path PLT provided outside is connected to the pressurizing chamber 40 and the pilot valve 1 'by a pilot path 7'.
The same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The four-way main valve 2 "has main pipes P, A, B, and R, where P is an inlet path, A and B are load paths B, and R is a return path.
The return path Dr2 of the pilot body 6 ″ is connected to the communication path 116.
At the return path R, and the spring supports 38a, 3
8b and the main springs 120a and 120b are for centering the main spool 106 "when not energized. In short, an external pilot type in which the pressure in the pressure passage PLT is opposed to the pressure in the cooperating damping chamber 9 through the pressure chamber 40 The main valve is a multi-path type, that is, a multi-port type, and the drain type is an internal drain type, and the object of the present invention can be achieved even with an external pilot type pressurized line PLT separated from the main line. The auxiliary piston 10 and the pilot spool may be integrated to form a stepped pilot spool, and the drain path Dr may be the outlet path A as long as there is no trouble. It is not limited to 101, but may be another type of analog electromagnetic actuator.

[0007]

As is apparent from the above description, the proportional throttle valve of the present invention has a three-way pilot valve, and further includes an operation room Py including a feedback spring 104 between the pilot spool and the main spool. Is positively made to cooperate with the damping chamber 9 through the resistance element 8, so that the pressure path PLT
Regardless of the internal pilot type and the external pilot type, the speed of the pilot spool and the main spool in the closed loop can be moderately offset, the damping effect on the system is extremely good, and the fluid force disturbance due to the main flow acting on the main spool is In addition, transient fluid force disturbance acting on the pilot spool can be absorbed, and the control path Pa and the return path Dr
The main spool can be set to a high gain with a high pressure difference between the control spool and the main spool. Therefore, even under high pressure, the system is stable and does not impair the response. However, there is an effect that the opening degree of the main spool can be held with high accuracy and the efficiency can be increased even if the main valve has the above. Further, the proportional throttle valve of the present invention increases the diameter of the pilot spool side exposed to the cooperating damping chamber 9,
Since the auxiliary piston 10 is inserted and the pilot spool is made to be stepped, the cooperating damping effect is further increased, and the controllability is further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic embodiment of a proportional throttle valve of the present invention.

FIG. 2 is a partial sectional view showing another embodiment of the proportional throttle valve of the present invention.

FIG. 3 is a partial sectional view showing another embodiment of the proportional throttle valve of the present invention.

FIG. 4 is a sectional view showing another embodiment of the proportional throttle valve of the present invention.

FIG. 5 is a sectional view of a main part showing a conventional proportional throttle valve.

[Explanation of symbols]

Dr2: return path, Pa: control path, PLT: pressurization path, Pp
... Pilot path, Py ... Operation room, 1 ... Pilot valve, 2
... Main valve, 3 ... Pilot spool, 7 ... Pilot path,
8 resistance element, 9 cooperating damping chamber, 10 auxiliary piston, 101 electromagnetic actuator, 104 feedback spring, 106 main spool.

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[Procedure amendment]

[Submission date] August 18, 1998 (1998.8.1)
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

In order to achieve the above object, the proportional throttle valve of the present invention basically has an analog electromagnetic actuator and a pilot path 108 having a throttle 107, as shown in FIG. A two-way pilot valve 10 having a control path Pa and a return path Dr2 connected with a branch
2, a pilot-operated main valve in which at least the pressure of the pressurizing path PLT and the pressure of the operation chamber Py are opposed, and the operation between the pilot spool of the pilot valve 102 and the main spool of the main valve. In a proportional throttle valve including a feedback spring 104 in the chamber Py and having a closed loop, the pilot valve 102 is connected to the pilot path Pp, the control path Pa, and the return path Dr2.
And the pilot path 108 extending from the pressurizing path PLT is connected to the pilot path Pp as the pilot path 7, and the operating chamber Py and the control path Pa are connected to a resistance element 8. The operation room Py is a cooperating damping room 9. Also, the proportional throttle valve of the present invention is shown in FIG.
As shown in FIG. 1, the pressure receiving surface on the pilot spool side of the pilot valve 1 that is exposed to the cooperating damping chamber 9 is connected to an auxiliary piston 10 having a diameter larger than the diameter of the pilot spool by the feedback spring 104 and the pilot spool. And between them.

Claims (2)

[Claims] 1. A two-way pilot valve 102 having an analog electromagnetic actuator, a control path Pa and a return path Dr2 that branch off to a pilot path 108 having a throttle 107, and at least the pressure of the pressurization path PLT and the operation chamber. A pilot-operated main valve opposing the pressure of Py;
The operation room Py between the pilot spool 105 of the pilot valve 102 and the main spool of the main valve.
And a three-way pilot valve 1 having a pilot path Pp, the control path Pa, and the return path Dr2. The pilot path 108 extending from the pressurizing path PLT of the main valve is connected to the pilot path Pp as the pilot path 7 and the operating chamber Py is connected to the control path Pa via a resistance element 8 to thereby perform the operation. A proportional throttle valve, wherein the chamber Py is a cooperating damping chamber 9. 2. The proportional throttle valve according to claim 1, wherein
The pilot valve 1 exposed to the cooperating damping chamber 9
A pressure receiving surface on the side of the pilot spool, wherein an auxiliary piston 10 having a diameter larger than the diameter of the pilot spool is provided between the feedback spring 104 and the pilot spool.