JPS6054026A - Feedback mechanism for hydro-pressure control valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a feedback mechanism in a hydraulic control valve. In a hydraulic control valve equipped with a hydraulic pressure control member that increases the hydraulic pressure in the upstream side of the liquid passage when the liquid is moved in the opposite direction, and decreases the hydraulic pressure when the liquid is moved in the opposite direction, the hydraulic pressure control member This relates to a mechanism that feeds back force related to the hydraulic pressure in the upstream portion of a liquid passage.Prior artOne type of the feedback mechanism described above includes a piston operated by hydraulic pressure controlled by a hydraulic pressure control member and a hydraulic pressure control member. There is a type in which an elastic member such as a spring is interposed between the pistons and the elastic member generates an elastic force corresponding to the displacement of the piston, and the generated elastic force is fed back to the hydraulic pressure control member.

However, a hydraulic control valve equipped with this type of feed bank mechanism has the disadvantage that overshoot tends to occur when the hydraulic pressure is suddenly increased. The feeder knock on the hydraulic pressure control member will not occur unless the piston moves forward and elastically deforms the elastic member by a certain amount, so if the hydraulic pressure increases rapidly, the feedback force will follow it. The feed pressure may become temporarily too small, causing the hydraulic pressure control member to move beyond the position where it should normally stop, causing the hydraulic pressure to temporarily become higher than the target value. .

This is the object of the invention, and therefore, its purpose is to increase the liquid pressure in the upstream part of the liquid passage when it is provided in the middle of a liquid passage and is moved in the forward direction by an actuator, and to increase the liquid pressure in the upstream part of the liquid passage, In a hydraulic pressure control valve equipped with a hydraulic pressure control member that lowers the hydraulic pressure when the hydraulic pressure is moved to It is an object of the present invention to provide a feedbank mechanism that provides feedback in the direction of moving a member in the opposite direction, and that can prevent or reduce the occurrence of overshoot even when hydraulic pressure is rapidly increased.

Structure of the Invention In order to achieve the above-mentioned object, the feed hack mechanism according to the present invention has (al
a driving piston receiving the hydraulic pressure in the chamber and the hydraulic pressure in the second chamber;
BL is connected directly or indirectly to the hydraulic pressure control member of the hydraulic pressure control valve, and receives the hydraulic pressure of the third chamber and the hydraulic pressure of the fourth chamber on pressure receiving surfaces facing oppositely to each other. The hydraulic pressure of the part whose hydraulic pressure is controlled by the hydraulic pressure control valve of the liquid passage is guided to the driven piston and (C) chamber, the second chamber is communicated with the third chamber, and the third chamber is connected to the fourth chamber. means for communicating with a communicating passage having a throttling effect and communicating the fourth chamber with a portion of the liquid passage downstream of the hydraulic pressure control valve; and an elastic member that urges the hydraulic pressure control member in the opposite direction with an elastic force that changes in response to changes in their relative positions.

Functions and Effects of the Invention In the feedback mechanism configured as described above, in a steady state, both the driving piston and the driven piston are stationary, and the elastic force of the elastic member is applied to the hydraulic pressure control member as a feed bath force. In the process where the hydraulic pressure is rapidly increased, the driving piston moves forward at high speed to increase the hydraulic pressure in the second and third chambers, and this increase in hydraulic pressure causes the force applied to the driven piston to be applied to the elastic member. Together with the elastic force, this is applied to the hydraulic pressure control member as a feed valve force. When the driving piston moves forward, the volume of the second chamber decreases, and the working fluid in the second chamber is pushed out to the third chamber, which is in communication with it, and then from the third chamber to the fourth chamber. However, the communication passage that connects the third and fourth chambers is said to have a throttling effect, so if the forward speed of the driving piston is high, the flow between the second and third chambers will be reduced. When hydraulic pressure is generated and the driving piston is moving forward, and the elastic force of the elastic member has not yet been sufficiently increased, the force based on this hydraulic pressure compensates for the lack of elastic force of the elastic member, and the feedback This prevents the hydraulic pressure control member from moving beyond its original target value due to a temporary shortage of soaking force.

Embodiments Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a housing which is the main body of the hydraulic control valve.For convenience of manufacture, it is divided into three parts, but after assembly, it functions as a single housing. This housing 10 is provided with a pressure boat 12 and a drain boat 14 , the pressure boat 12 being connected to a pump circuit 20 by a line 18 with a restriction 16 , while the drain boat 14 is connected to a pump circuit 20 by a line 22 . It is connected to tank 24. Therefore, a portion of the hydraulic oil pumped from the tank 24 by the pump 26 is guided to the pressure boat 12 by the line 18, and from the drain boat 14 to the line 22.
It will be returned to the tank 24 through the process.

The flow path from this pressure boat 12 to the drain boat 14 is constricted by a spool 28 as a hydraulic control member. Spool 28 is housing 1
It is fitted into a spool hole formed in the spool hole substantially oil-tightly and slidably in the axial direction, and is provided with a land 30 at one end.

The land 30 is formed to cut off communication between the pressure boat 12 and the drain boat 14, and a notch 32 as shown in enlarged form in FIGS. 2 and 3 is formed in the land 30. The hydraulic oil led to the pressure boat 12 is spouted from an annular groove 34 of the spool 28 through a notch 32 into a low pressure chamber 36. Furthermore, as is clear from FIG. 2, the notch 32 is formed to be deeper at the end of the land 30, so that as the spool 28 moves to the right in FIG. The flow path area decreases, and the throttling effect on the hydraulic oil flowing from the pressure boat 12 to the drain boat 14 increases.

An armature tube 38 is fixed to the end of the low pressure chamber 36 of the housing 10 by screwing, and an armature 40 is disposed within the armature tube 38 so as to be movable in the axial direction. A working protrusion 42 protrudes from the end surface and can come into contact with one end of the spool 28. Further, a solenoid coil 44 is fixed to the outside of the armature tube 38, and this solenoid coil 44 is connected to an AC power source 46 whose voltage is variable. Therefore, when the solenoid coil 44 is supplied with current, the armature 4
0 is attracted to the central position of the solenoid coil 44, applying a positive force to the spool 28 via the actuating projection 42, ie, to the right in FIG. This positive force is applied to the solenoid coil 4 by the AC power source 46.
In this embodiment, the solenoid assembly configured as described above functions as an actuator that drives the spool 28, which is a hydraulic control member, in the forward direction. .

This spool 28 also has a feed pa/vine mechanism 50.
A force is applied in the opposite direction, that is, to the left, and the spool 28 is stopped at a position where this force and the force in the positive direction by the armature 40 are balanced. The feedback mechanism 50 includes a driving piston 52 and a driven piston 54. The driving piston 52 is composed of a piston body 56 that is fluid-tightly and slidably fitted into the housing 10 and a plunger 58 that is fixed thereto. It is adapted to receive the hydraulic pressure of the chamber 62. The feedback passage 63 connects the pressure boat 1 to the chamber 60.
2 hydraulic pressure is introduced.

Further, 64 is a low-level tank, and is always communicated with the tank 24 via a drain boat 66 and a pipe line 68.

On the other hand, the driven piston 54 is provided at a position concentrically facing the driving piston 52, is fixed to one end of the spool 28, and receives the hydraulic pressure of the third chamber 70 and the fourth chamber 72 on pressure receiving surfaces facing oppositely to each other. It is like that. The third chamber 70 is formed to be continuous with the second chamber 62, and the fourth chamber 72 is a communication passage 74 with a throttle effect formed between the outer peripheral surface of the driven piston 54 and the housing 10. communicated by. And the fourth room 72
is communicated with the low pressure chamber 36 through a communication passage 76.

A spring 78 is provided between the driving piston 52 and the housing 10, and urges the driving piston 52 toward the retreating side, that is, toward the -th chamber 60 side.

Further, a spring 80 as an elastic member is provided between the driving piston 52 and the driven piston 54. Note that the spring 78 is provided to share part of the operating force of the driving piston 52, since a large solenoid assembly would be required if the spring 80 were to receive all of the operating force of the driving piston 52. It is something. In this embodiment, the G spring 78 has a larger spring force than the spring 80, but when the hydraulic pressure acting on the driving piston 52 is low, the spring 78
It is also possible to omit 8.

When a constant voltage is applied by the AC power source 46 to the solenoid coil 44 of the hydraulic control valve configured as described above, and a constant hydraulic pressure is introduced from the pump circuit 20 to the pressure boat 12, the spool 28 It is stable in the position shown in Figure 1.

In other words, the force in the positive direction that the armature 40 applies to the spool 28 based on the attraction force of the solenoid coil 44 is balanced with the force in the opposite direction that the spring 8o applies to the spool 28.

When the voltage of the AC power source 46 is gradually increased from this state, the positive force applied by the armature 40 to the spool 28 increases, causing the spool 28 to move to the right against the elastic force of the spring 80. As a result, the area of the flow passage in the notch 32 is reduced and the throttling effect is increased, so the oil pressure of the pressure boat 12 is increased and this is caused by the feed hack passage 63.
is transmitted to the plunger 58 of the driving piston 52 by. As a result, the driving piston 52 is moved by the spring 78.8.
The spring 80 is compressed and the force in the opposite direction relative to the spool 28 increases. That is, as the pressure in the pressure boat 12 increases, the driving piston 58 moves forward, and this forward movement causes the spring 8o to move forward.
As a result, the amount of pressure increase in the pressure boat 12 and the amount of increase in the pressure applied to the spool 28 in the opposite direction are proportional to each other. Then, the spool 28 stops when this force in the opposite direction is balanced with the force in the forward direction by the armature 4o, so the pressure of the pressure boat 12 increases the suction force of the armature 40, that is, the voltage of the AC power source 46. The hydraulic pressure of the pressure boat 12 can be taken out and used for various purposes.

The above is the operation when the voltage of the AC power supply 46 is gradually increased, and when the voltage is suddenly increased, the operation is as follows. If the voltage is increased rapidly, the positive force applied by the armature 40 to the spool 28 will also be increased rapidly, resulting in a sudden increase in the oil pressure in the pressure boat 12. This second rise is then transmitted to the first chamber 60 through the feedback passage 63, causing the driving piston 52 to move forward at high speed. When the driving piston 52 moves forward, the volume of the second chamber 62 decreases, and the hydraulic oil there is supplied to the third chamber 70 and further pushed out to the fourth chamber 72 via the communication passage 74. The passage 74 is narrowed to provide a throttling effect, so that the second chamber 6
Hydraulic pressure is generated in the second and third chambers 70, and the driven piston 54 receives a leftward force due to this hydraulic pressure. That is, when the voltage of the AC power supply 46 is suddenly increased, not only the elastic force of the spring 80 but also the force based on the oil pressure is applied to the spool 28 via the driven piston 54 as a feedback force. The force based on the hydraulic pressure increases as the forward speed of the driving piston 52 increases, that is, as the hydraulic pressure of the pressure boat 12 increases rapidly, it counteracts the force in the positive direction of the armature 40, and the force on the spool 28 increases.
This prevents sudden movement in the positive direction.

An example of the experimental results conducted to confirm this effect is shown in the fourth section.
As shown in FIG. The graph in FIG. 4 shows the connection path 74.
This figure shows the change in the oil pressure of the pressure boat 12 when a voltage is applied to the solenoid coil 44 for a certain period of time in a state where the flow path area is sufficiently large so that no feedback force based on oil pressure is obtained. However, overshoeing is clearly occurring. On the other hand, FIG. 5 shows the results when the flow area of the communicating path 74 is sufficiently reduced to provide a throttling effect, and it is clear that according to the present invention, the occurrence of overshoot can be prevented. clearly shown.

FIG. 6 shows another embodiment of the invention. In this embodiment, the present invention is applied to a pilot pressure control valve that controls the pilot pressure of a seating valve type main hydraulic control valve. The main hydraulic control valve 82 has a valve seat 84 formed in the housing 10.
and a poppet valve 86, and one end of a spring 88 that biases the poppet valve 86 in the closing direction is attached to a piston 90.
As the pilot pressure acting on the piston 90 increases, the piston 90 moves forward while compressing the spring 94, thereby compressing the spring 88 and
- The elastic force acting on the valve 86 is increased and the hydraulic pressure of the pressure boat 96 is increased. and,
A spool 2 is placed in the middle of the drain passage of this main hydraulic control valve 82.
A pilot pressure control valve 8 is provided, and the hydraulic pressure controlled by this valve is applied to the piston 90 as pilot pressure.

The configuration of this pilot pressure control valve is similar to the hydraulic control valve of the previous embodiment, so corresponding parts are given the same reference numerals and detailed explanations are omitted. However, in this embodiment, the main hydraulic control valve 82 A piston 9o for controlling the valve opening pressure of the feed bank mechanism 50 is used as a driving piston of the feed bank mechanism 50. That is, the arm 100 is extended from the piston 90, and the spring 80 is disposed between the arm 100 and the driven piston 54.

Therefore, the oil chamber formed behind this piston 9o is the -th chamber 60. The oil chambers formed in the front function as the second chambers 62, respectively.

Another embodiment of the invention is shown in FIG. In this embodiment, the present invention is applied to a pilot pressure control valve for controlling the pilot pressure of a spool type directional flow rate control valve. In the figure, +02 is a housing, which is connected to the pump (P bow) 104, A bow (1-106) and B bow (108) connected to an actuator such as a hydraulic cylinder.
．． It also includes a T-boat 110 connected to the tank. Inside this housing 102 is a spool 1.
12 is provided so as to be slidable in the axial direction.

The spool 112 is normally kept in a neutral position by a pair of springs 114 and spring receivers 116 provided on each side to cut off all boat connections. When the applied pressure is increased, the boat is moved to the left or right against the elastic force of the spring 114, and the P boat 104 is connected to either the A boat 1-106 or the B boat 108. The T-boat 110 is connected to the remaining one to control the direction, and the flow rate between these boats is also controlled depending on the distance traveled from the neutral position.

The pilot pressure acting on both ends of the spool 112 is controlled by two sets of viroft pressure control valves, which are constructed symmetrically to each other, and the configuration of the two sets is shown in FIG. Since it is almost the same as the embodiment, the same reference numerals as in the embodiment of FIG. As is clear from the figure, in this embodiment, the spool 112 functions as a driving piston, and when the left pilot pressure control valve is activated, the oil chamber formed on the right side of the spool 112 functions as the driving piston. It functions as a chamber 60.

Another embodiment is shown in FIG. In this embodiment, the piston 11
8 is the spring 1 caused by the hydraulic pressure supplied to the oil chamber 120.
22 and drives a driven member 124 (for example, a swash plate-type variable discharge capacity control bin for controlling the inclination angle of the swash plate of the pump) that is engaged with the piston 118. Oil chamber 1 of actuator 126
The present invention is applied to a hydraulic pressure control valve that controls the hydraulic pressure supplied to the hydraulic pressure 20. In this embodiment, the piston 118 of the actuator 126 is used as a driving piston, and the oil chamber 120 functions as the first chamber.
Since this embodiment is similar to the embodiment shown in TyJ, corresponding parts will be given the same reference numerals and detailed explanation will be omitted.

In the present embodiment, bypass passages 1 and 28 are formed from the third chamber 70 to the communication passage 76, and a variable throttle 130 is provided in the middle of the bypass passages 1 and 28 to connect the communication passage 76. The aperture effect of the circuit 74 can be adjusted.

In this embodiment, the force acting on the piston 118 is not only the force based on the oil pressure led to the oil chamber 120 and the elastic force of the springs 80 and 122, but also the reaction force from the driven member 124, so that the force of the spring 80 is The elastic force and the oil pressure in the oil chamber 120 do not necessarily have a one-to-one correspondence. That is, if the reaction force from the driven part JA124 increases while the device of this embodiment is stable, the piston 118 will move toward the oil chamber 120, but as a result, the elastic force of the spring 80 will decrease. decreases, spool 2
8 moves in the positive direction to enhance the throttling effect in the notch 32, the oil pressure of the pressure port 12 increases, and eventually the oil chamber 1
The oil pressure in the driven member 124 increases to a value that can counteract the reaction force from the driven member 124. In the end, oil chamber 12
The zero oil pressure is controlled to generate a force in the opposite direction on the spring 80 that is the same magnitude as the force in the forward direction applied from the armadure 40 to the spool 28, regardless of the reaction force from the driven member 124. It is.

Yet another embodiment of the invention is shown in FIG. In this embodiment, another oil chamber 132 is provided that applies hydraulic pressure opposite to the oil pressure in the oil chamber 120 to the piston 118. The oil pressure of the pump circuit 20 is guided to this oil chamber 132 through a communication path 134. The pressure receiving area of the piston 118 on the oil chamber 132 side is approximately 2 times the pressure receiving area on the oil chamber 120 side.
The force acting on the piston 118 is balanced when approximately half the hydraulic pressure of the pump circuit 20 is applied to the oil chamber 120. This oil chamber 132 corresponds to the springs 78, 94', 11 in each of the above embodiments.
4 and 122, etc., the driving piston 52. Piston 90. It applies a force in the opposite direction to the force applied to the spool 112, piston 118, etc. by the hydraulic pressure in the second chamber 60, oil chamber 120, etc. In this sense, the oil chamber 132, together with the above-mentioned springs, serves as a counterforce applying means. It should be referred to collectively.

Yet another embodiment of the invention is shown in FIG.

In this embodiment, the feed knob passage 63 and the pressure boat 12 are connected to each other by the action of the spool 28.
It differs from the embodiment of FIG. 1 in that it can be alternatively communicated with 14).

That is, in the embodiment of FIG. 1, the pressure, l;
In this embodiment, the boat designated as number 2 is designated as a pressure take-off boat 140, which is provided separately from pressure boat number 12. In addition to the land 30 and notch 32, the spool 28 has a land 142 and a notch 144.
are provided, and the feedback passage 63 and the pressure take-off boat 140 are brought into communication with the drain boat 14 and the pressure boat 12, respectively, via these notches 32 and 144.

The functions and effects of this embodiment are almost the same as those of the embodiment shown in FIG. 1, so the explanation will be omitted. It has the advantage of requiring less. Furthermore, in this embodiment, the oil pressure of a short portion of the oil passage from the pressure boat 12 to the drain boat 14 that is constantly in communication with the pressure take-off boat 140 is controlled by the spool 28, which is a hydraulic control member. It is a part of it.

Although several embodiments of the present invention have been described above, the present invention can be further implemented in various embodiments. For example, in each of the above embodiments, the spool, which is a hydraulic control member,
The armature is actuated by an AC solenoid assembly that is attracted by an AC solenoid. In this case, the suction force of the solenoid is less likely to change due to temperature, and there is no hysteresis when the oil pressure rises or falls. This has the advantage of providing a smaller, more stable and more accurate hydraulic control valve, but it can also be operated by a DC solenoid assembly in which the armature is drawn in by a DC solenoid, and it also has the advantage of having a manual operating mechanism, etc. It is also possible to actuate it by an actuator. The hydraulic control member is not limited to the spool, but may be any member that can control the hydraulic pressure by balancing the forward driving force applied by the actuator with the reverse feed bath force applied by the feed bath mechanism. It is. Further, the communication passage having a throttling effect that connects the third chamber and the fourth chamber is not necessarily limited to the annular gap formed between the outer peripheral surface of the driven piston and the housing,
the driven piston is substantially liquid-tightly fitted to the housing;
A communication passage with a throttling effect may be formed in the driven piston, and as in the embodiment shown in FIG.
A restriction may be provided in the bypass passage 17& formed in the housing. Further, in each of the embodiments described above, the fluid whose pressure is controlled is hydraulic oil, but other liquids such as suspensions may be used.

Although not illustrated in detail, it is of course possible to carry out the present invention in various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a hydraulic control valve including a feedback mechanism, which is an embodiment of the present invention. FIG. 2 is a partially cutaway front view showing only the spool of the hydraulic control valve, and FIG. 3 is a plan view showing a portion of the spool. FIGS. 4 and 5 are graphs showing an example of an experiment conducted to confirm the effects of the present invention. FIG. 4 is a graph when the present invention is not applied, and FIG. 5 is a graph when the present invention is applied. FIG. 3 is a diagram showing hydraulic control characteristics. FIG. 6 is a front view showing an embodiment in which the present invention is applied to a pilot pressure control valve that controls the pilot pressure of a main hydraulic control valve. FIG. 7 is a front sectional view showing an embodiment in which the present invention is applied to a pilot pressure control valve for controlling the biloft pressure of a spool-type directional flow rate control valve. FIGS. 8 and 9 are front sectional views showing respective embodiments in which the present invention is applied to a hydraulic control valve that controls the working oil pressure of an actuator. FIG. 10 is a front sectional view showing another hydraulic pressure control valve equipped with a feedback mechanism, which is an embodiment of the present invention. 10: Housing 12: Pressure port 14: Drain boat 28,112 Varnish spool 30.1
42: Land 32.14.4: Notch 40: Armature 44: Solenoid coil 46: AC power supply 50:
Feedbank mechanism 52: Driving piston 54: Driven piston 60: -th chamber 62: Second chamber 63: Feedback passage 70: Third chamber 72: Fourth chamber 74, 76: Communication passage 78, 80, 94, 114, 122 Nispring 82:
Main hydraulic control valve 90.118: Piston 120.132
Two oil chambers 126: Actuator 140: Pressure take-off boat Applicant: Technol Co., Ltd. Figure 3 Figure 4 Figure 5 Ima l

Claims (1)

[Claims] The device is provided in the middle of the acid liquid passage, and increases the liquid pressure in the upstream side of the acid liquid passage when moved in the forward direction by an actuator, and decreases the liquid pressure when moved in the opposite direction. A hydraulic control valve having a hydraulic pressure control member that moves the hydraulic pressure control member in the opposite direction by applying a force related to the hydraulic pressure in an upstream portion of the liquid passage to the hydraulic pressure control member. The mechanism provides feedback in the direction in which the hydraulic pressure is controlled, and includes a driving piston that receives hydraulic pressure in the first chamber and hydraulic pressure in the second chamber on pressure receiving surfaces facing oppositely to each other, and a driving piston that receives hydraulic pressure in the first chamber and hydraulic pressure in the second chamber, respectively, and a mechanism that connects the hydraulic pressure control member directly or through another member. a driven piston that is indirectly connected to the piston and receives the hydraulic pressure of the third chamber and the hydraulic pressure of the fourth chamber, respectively, on pressure receiving surfaces facing oppositely to each other; the second chamber communicates with the third chamber, the third chamber communicates with the fourth chamber through a communication passage having a throttling effect, and the fourth chamber communicates with the downstream portion of the liquid passage. a means for communicating with the hydraulic pressure control member provided between the driving piston and the hydraulic pressure control member, and controlling the hydraulic pressure with an elastic force that changes in response to a change in the relative position between the driving piston and the hydraulic pressure control member. A feedback mechanism in a hydraulic control valve, comprising an elastic member that biases the member in the opposite direction.