JPH064405U - Fluid pressure spool type servo valve - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the working fluid is a low-viscosity fluid, the internal leak rate is small and the handling flow rate can be increased.
Therefore, a fluid pressure spool type servo valve excellent in economy and practicality is aimed at. In a fluid pressure spool type servo valve having a flow passage formed of a valve element and a spool, a supply port 25 disposed in the central portion of the flow passage and an outer end side of the supply port 25 are disposed. Load ports 26 and 27, return ports 28 arranged on the outer end sides of the load ports 26 and 27, and drain ports 30 and 31 arranged on the outer end sides of the return ports 28, respectively. A spool displacement motor 1 connected to one end of the spool 15 through the vertical interlocking member 8 and the linear movement mechanism, and a spool displacement meter 22 attached to the other end of the spool 15. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fluid pressure spool type servo valve.

[0002]

[Prior art]

 Conventionally, as a fluid pressure spool type servo valve, for example, as shown in the vertical cross-sectional view of FIG. 2, a pilot portion 05 including a torque motor 01, a nozzle 02, a nozzle 03, a flapper 04, a body 06, and a sleeve. There is known a flapper type formed by a main spool portion 09 composed of 07, a spool 08 and the like. In such a flapper type device, the tilting of the amateur 010 → the lateral displacement of the flapper 04 → the change in the clearance between the flapper 04 and the nozzle 02 and the nozzle 03 → the pressure unbalance between the pressure control chamber 011 and the pressure control chamber 012. Displacement of spool 08 proportional to the input current is obtained by a series of operations such as balance → displacement of spool 08 → neutral movement of flapper 04 via feedback spring 013, which causes displacement between spool 08 and body 06 ports. The flow direction and flow rate of the flowing fluid are controlled. Here, in the case of an ordinary servo valve, 014 is an inlet orifice 015, a nozzle 02, and the opening of the nozzle 03 each have a hole diameter of 0.1 to 0.2 mm, which is very small. It is an inlet filter inserted to prevent clogging.

By the way, in this type of servo valve device, the pilot flow rate OQ _L1 is always required to displace the spool 08 in the left-right direction. Further, the spool displacement Ox of the spool 08 is 1 to 1.5 mm, and in order to minimize the ratio of the dead zone region to the controllability and the spool displacement amount and to increase the output flow rate control range, the partial enlarged transverse cross section in FIG. As shown in the front view, the clearance OC between the sleeve 07 and the spool 08 is set to several microns to several tens of microns, but even when the valve is closed, due to the structure of this valve, the supply port 016 has both ends of the spool 08. The return port 017 is disposed in the center of the spool 08. As a result, the internal leak points are: the supply port 016 → the load ports 018, 019 → the return port 017, the internal leak amount OQ _L3 , the supply port 016 → the pressure control chambers 011 and 012, the internal leak amount OQ _L2, and the supply port. 016 → inlet filter 014 → pressure control chambers 011 and 012 → nozzle flapper 04 pilot flow rate OQ _L1 occurs, and these amounts decrease as the supply pressure OP _S increases. The higher the energy efficiency of the device, the more it decreases. The supply pressure OP _S >> pressure control chamber pressure.

That is, the qualitative relationship between the internal leak amount OQ _L and the supply pressure OP _S is that the internal leak amount OQ _L increases as the supply pressure OP _S increases, as shown in FIG. There is. The relationship between the internal leak amount OQ _L3 , the clearance OC between the spool 08 and the sleeve 07, and the overlap amount OΔx between the spool 08 and the sleeve 07 is as shown in the diagram in FIG. The amount OQ _L3 increases and decreases as the lapping amount OΔx increases. In both cases, the internal leak amount OQ _L3 tends to increase as the fluid viscosity decreases, as indicated by the broken line. Further, the output flow rates OQ _A , OQ _B from the load ports 018, 019 when the spool 08 is displaced in the left-right direction have the characteristics shown in the diagram of FIG. 6, and generally, as shown by the solid line, From the aspect of controllability, the lap amount OΔx is set to almost zero in order to reduce the dead zone Z. If the lap amount OΔx is increased, the internal leak amount can be reduced, but as shown by the chain line, in the case of high viscosity fluid such as oil, the dead zone region where the flow rate becomes zero when the spool displacement amount Ox is near zero becomes large and the control The sex becomes worse.

Therefore, such a device has the following drawbacks. (1) Internal leakage mainly occurs at three locations structurally, so if the working fluid is a low viscosity fluid, the internal leakage amount OQ_L1, OQ_L2, OQ_L3Increase energy efficiency and reduce energy efficiency, thus deteriorating economic efficiency. (2) Since the movement amount of the spool 08 is mechanically small, the wrap amount between the spool land and the valve body is limited, and therefore the internal leak amount OQ when the port is closed. _L Increase and economic efficiency deteriorates. (3) Also, since the spool movement is mechanically small, the size of the port is limited, and therefore the flow rate when the port is opened is restricted, making it difficult to increase the capacity of the device.

[0006]

[Problems to be solved by the device]

 The present invention has been proposed in view of such circumstances, and even when the working fluid is a low-viscosity fluid, the internal leak amount is small, and the handling flow rate can be increased. Therefore, it is economical and practical. It is an object of the present invention to provide an excellent fluid pressure spool type servo valve.

[0007]

[Means for Solving the Problems]

 Therefore, in the present invention, in a fluid pressure spool type servo valve having a flow passage formed by a valve body and a spool, a supply port disposed at a central portion of the flow passage and an outer end side of the supply port are provided. , A return port disposed on the outer end side of each load port, a drain port disposed on the outer end side of each return port, and one end of the spool. And a spool displacement meter connected to the other end of the spool through a link member and a linear movement mechanism, and a spool displacement meter attached to the other end of the spool.

[0008]

[Action]

 According to such a configuration, since the spool displacement motor connected to the one end of the spool through the interlocking member and the linear movement mechanism is provided, the following operation is performed. (1) A supply port can be arranged at the center of the flow path port arrangement, and the number of leak occurrence points can be reduced from the conventional three locations to one location, and the amount of internal leak is greatly reduced. (2) By linearizing the high-speed rotation of the displacement motor, the stroke of the spool can be increased, and the amount of lap between the spool land and the valve body can be increased. , The amount of internal leak when handling low viscosity fluid is greatly reduced. (3) It is possible to increase the stroke of the spool and easily increase the flow rate of the servo valve.

[0009]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. In the vertical cross-sectional view of FIG. 1, reference numeral 1 is parallel to the axis of the valve body 2 through a motor mount 3 at the center of the upper surface of the valve body 2 in the shape of a horizontal and thick wall. The motor 4 for displacement fixed to is a horizontal cylindrical bearing support cylinder forming a part of the motor mount 3, and 5 is a bearing internally supported by the right end of the bearing support cylinder 4. 6 is a ball screw in which a screw is formed on the right end of a horizontal cylindrical member, 7 is a coupling that connects the left end of the ball screw 6 supported by a bearing 5 and the output shaft of the displacement motor 1, and 8 Is provided with a nut housing 10 which is screwed into the right end of the ball screw 6 at the upper end thereof, a guide shaft 11 extending in parallel with the ball screw 6 at an appropriate length on the left side of the center, and a horizontal screw at the lower end. It is a vertical interlocking member having holes 12 formed therein.

Reference numeral 13 is a spool hole penetrating the axial portion of the valve body 2, 14 is a plurality of spool lands fitted onto the spool 15 inserted in the spool hole 13 at appropriate intervals, and 16 is an upper surface of the valve body 2. It is a horizontal guide shaft support hole protruding from the right end portion. Reference numeral 17 denotes a supporting rod which is screwed onto the left end portion of the spool 15 on the same axis line and extends to the left by an appropriate length, 18 denotes a core coaxially fitted to the left end portion of the support rod 17, and 19 denotes a core 18 coaxially. Is a core tube in which the coil 20 is coaxially fitted on the outer peripheral surface of the valve body, and 21 is a displacement meter housing that supports a displacement meter 22 formed of the core 18 to the coil 20 on the left end surface of the valve body 2. is there. Reference numeral 23 is a set screw for fixing the right end of the spool 15 to the vertical interlocking member 8, 24 is a seal fitted in the right end penetrating portion of the valve body 2 of the spool 15, and 25 is a central portion of the lower surface of the valve body 2. The supply ports 26 and 27 are arranged on the left and right of the supply port 25 of the valve body 2, and the load ports 28 are arranged on the left and right of the load ports 26 and 27 of the valve body 2, respectively. Return ports 30 and 31 are drain ports disposed on the left and right of the return port 28 of the valve body 2, respectively.

In such a device, when the displacement motor 1 is rotated, the vertical interlocking member 8 moves horizontally in the left-right direction by the action of the ball screw 6, the nut 7, etc. The flow direction and flow rate of the fluid between the flow path ports in the valve body 2 at that time are controlled by the rotation direction and rotation speed of the displacement motor 1, and the displacement amount of the spool 15 is determined by the displacement meter 22. Detected by. Therefore, in the figure, when the spool 15 is displaced to the left, the flow of the fluid is: supply port 25 → load port 26 → cylinder (not shown) → load port 27 → return port 28, and the spool 15 moves to the right. When displaced, the supply port 25 → the load port 27 → the load port 26 → the return port 28. Further, as shown in the same figure, in the valve closed state, the pressure fluid acting on the supply port 25 flows from the gap between the valve body 2 and the spool land 14 into the load port 26 as indicated by the leak amount _QL3. And after leaking to the load port 27, it leaks to the return port 28.

On the other hand, the leak amount Q _L2 that leaks from the return port 28 to the drain ports 30 and 31 through the gap between the valve body 2 and the spool land 14 is a general use condition in which the return port 28 is close to the atmospheric pressure. , Almost none, can be ignored. Further, in this apparatus, since the spool 15 is a direct drive type using the motor 1, the ball screw 6, etc., the spool displacement x = 3 to 4 mm can be easily obtained. Therefore, the lap amounts Δx ₁ and Δx ₂ can be made larger than before, and the internal leak amount _QL3 can be suppressed to a lower level even when a low-viscosity fluid is used. At that time, since the spool displacement x and the output flow rates Q _A and Q _B of the load ports 26 and 27 are low-viscosity fluids, do they flow to the load ports 26 and 27 through the clearance C between the valve body 2 and the spool 15. As shown by the broken line in FIG. 6, the dead zone in the region where the output flow rates Q _A and Q _B are zero becomes small, and the controllability is not significantly impaired.

According to the apparatus of the embodiment as described above, the spool displacement motor connected to the one end of the spool through the interlocking member and the linear motion mechanism is provided, and therefore the following effects can be obtained. (1) It is possible to arrange the supply port in the central part in the arrangement of the flow path ports, and it is possible to reduce the number of leak occurrence points from the conventional three locations to one location, which significantly reduces the internal leak amount. Energy loss is reduced and economic efficiency is improved. (2) By linearizing the high-speed rotation of the displacement motor, the stroke of the spool can be increased, and the amount of lap between the spool land and the valve body can be increased. In particular, the amount of internal leak when handling low-viscosity fluid is greatly reduced, thus improving the economical efficiency. (3) Since the stroke of the spool can be increased, it is possible to easily increase the flow rate of the servo valve, and thus the practicality is improved.

[0014]

[Effect of device]

 In short, according to the present invention, in a fluid pressure spool type servo valve having a flow passage formed by a valve body and a spool, a supply port disposed in the central portion of the flow passage and an outer end side of the supply port are provided. Load ports respectively arranged, return ports respectively arranged at outer ends of the respective load ports, drain ports respectively arranged at outer ends of the respective return ports, and one end of the spool. In the case where the working fluid is a low-viscosity fluid, the motor for displacing the spool connected through the interlocking member and the linear movement mechanism and the spool displacement gauge attached to the other end of the spool are provided. In addition, the present invention is extremely useful in the industry because it has a small internal leak amount and can handle a large flow rate, thus providing a hydraulic spool type servo valve that is highly economical and practical. It is intended.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a known fluid pressure spool type servo valve.

FIG. 3 is a partially enlarged view showing the spool 08 of FIG.

FIG. 4 is a diagram showing a relationship between a supply pressure of the servo valve of FIG. 2 and an internal leak amount.

5 is a diagram showing the relationship between the spool wrap amount of the servo valve of FIG. 2, the clearance between the spool and the sleeve, and the internal leak amount.

FIG. 6 is a diagram showing a relationship between spool displacement and output flow rate of the servo valve of FIG.

[Explanation of symbols]

1 Displacement Motor 2 Valve Body 3 Motor Mounting Base 4 Bearing Support Tube 5 Bearing 6 Ball Screw 7 Coupling 8 Vertical Interlocking Member 9 Nut 10 Nut Housing 11 Guide Shaft 12 Screw Hole 13 Spool Hole 14 Spool Land 15 Spool 16 Guide Shaft Support hole 17 Support rod 18 Core 19 Core tube 20 Coil 21 Displacement meter housing 22 Displacement meter 23 Set screw 24 Seal 25 Supply port 26 Load port 27 Load port 28 Return port 30 Drain port 31 Drain port C Clearance Q _A Output flow rate Q _B Output flow rate Q _L2 leak amount Q _L3 leak amount Δx ₁ lap amount Δx ₂ lap amount

Claims (1)

[Scope of utility model registration request] 1. A fluid pressure spool type servo valve having a flow passage formed by a valve element and a spool, wherein a supply port disposed in a central portion of the flow passage and an outer end side of the supply port are disposed. Installed load ports, return ports provided on the outer ends of the respective load ports, drain ports provided on the outer ends of the respective return ports, and an interlocking member at one end of the spool. And a motor for displacing the spool, which is connected through a linear movement mechanism,
A fluid pressure spool type servo valve comprising a spool displacement gauge attached to the other end of the spool.