Zero-position-adjustable electro-hydraulic servo valve

Abstract

The utility model belongs to the technical field of mechanical engineering, and relates to a zero-position-adjustable electro-hydraulic servo valve. The electro-hydraulic servo valve mainly comprises a prestage and a slide valve stage, the prestage is arranged at the upper end of the sliding valve stage, and the sliding valve stage comprises a valve element, a valve sleeve and a zero position adjusting mechanism. The zero position adjusting mechanisms are arranged at the two ends of the valve element. The zero position adjusting mechanism is composed of a valve sleeve ejector block and a zero setting screw. Valve sleeve ejecting blocks are arranged between the two end faces of the valve sleeve and the end cover, the end cover is fixed to the end face of the shell, the zero setting screws penetrate through end cover threaded holes, the feeding amount of the valve sleeve ejecting blocks can be changed by adjusting the zero setting screws on the two sides, and therefore the relative positions of the valve sleeve, the shell and the prestage in the axial direction of the valve element are adjusted, and the overall zero position of the servo valve is adjusted. The servo valve and the zero position adjusting mode have the advantages that the zero position of the servo valve can be flexibly adjusted in real time by combining the use working condition of the servo valve and the characteristics of the system, the matching performance of the servo valve and the system can be remarkably improved, and the external field use and maintenance cost of the servo valve is effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of mechanical engineering and relates to a zero-position adjustable electro-hydraulic servo valve. Background Art

[0002] At present, electro-hydraulic servo valves are widely used in aircraft, ships, aviation, aerospace, metallurgy and other fields, and are often faced with harsh environments such as high temperature, high pressure, and high vibration values. This puts higher requirements on the reliability and stability of the servo valve, among which the zero position stability of the servo valve is particularly important for ensuring the output stability of the system. However, when the servo valve is used for a long time, it will be affected by factors such as preload release, magnetic property changes, and vibration. Slight changes in mechanical metal components will change the zero position of the servo valve, and returning to the factory for re-inspection will greatly increase the maintenance cycle and cost of the product; at the same time, when the servo valve is debugged with the system, the adjustable zero position design can greatly improve the matching of the product and the system, which is of great significance for improving the assembly qualification rate of the servo valve and the system. Therefore, designing an electro-hydraulic servo valve or zero bias adjustment method with adjustable zero bias, simple operation, stable and reliable performance can effectively reduce the field maintenance time and improve the matching of the servo valve and the system, which has very important theoretical significance and engineering application value. Utility Model Content

[0003] The servo valve zero position is the geometric zero position where the no-load flow is zero. The existing electro-hydraulic servo valve zero position is usually divided into electrical zero position and mechanical zero position. The electrical zero position of the servo valve is guaranteed by the relative position of the torque motor components to achieve proportional deflection of the armature assembly guide plate with the input current; the mechanical zero position is guaranteed by the relative position of the pre-stage and the slide valve pair to achieve zero no-load flow of the slide valve stage when the pre-stage is zero. The traditional servo valve sleeve is fixedly connected to the housing by controlling the tolerance, and the mechanical zero position of the servo valve is ensured by adjusting the phase position of the pre-stage and the slide valve pair. After the servo valve zero position debugging is completed, the servo valve pre-stage will be enclosed in the upper cover and locked, and the zero position cannot be adjusted when used in the field.

[0004] The purposes of this utility model are as follows:

[0005] Provided is a zero-position adjustable electro-hydraulic servo valve, which adjusts the relative position of the spool valve pair and the pre-stage through the zero-position adjustment device located on both sides of the spool valve pair, so as to achieve the effect of adjusting the servo valve zero position and ensuring the zero position is stable and reliable. The servo valve and the zero-position adjustment method have the advantages of being able to flexibly adjust the servo valve zero position in real time in combination with the servo valve use conditions and system characteristics, which can significantly improve the matching of the servo valve and the system, and effectively reduce the field use and maintenance costs of the servo valve.

[0006] The technical solution of the utility model is as follows:

[0007] The utility model discloses a flow-adjustable electro-hydraulic servo valve; the electro-hydraulic servo valve mainly comprises a pre-stage and a slide valve stage; the pre-stage is arranged at the upper end of the slide valve stage, the slide valve stage comprises a valve core, a valve sleeve and a zero-position adjustment mechanism; the zero-position adjustment mechanism is arranged at both ends of the valve core; the zero-position adjustment mechanism consists of a valve sleeve top block and a zero-adjusting screw; a valve sleeve top block is arranged between the two end surfaces of the valve sleeve and an end cover, the end cover is fixed to the end surface of a shell body, the zero-adjusting screw passes through a threaded hole of the end cover, and the feed amount of the valve sleeve top block can be changed by adjusting the zero-adjusting screws on both sides, thereby adjusting the relative position of the valve sleeve and the shell body and the pre-stage along the axial direction of the valve core, and then adjusting the overall zero position of the servo valve.

[0008] Furthermore, there is a conical groove on the outer side of the valve sleeve top block, and the head of the zero adjustment screw presses the valve sleeve top block inward in the conical groove.

[0009] Furthermore, the zero-position adjustment mechanism also includes a limit pad; for different types of valve sleeves and housings, the maximum movement of the valve sleeve can be limited by adjusting the thickness of the limit pad to avoid excessive adjustment causing the valve sleeve and the housing to shear the feedback rod and cause damage to the feedback rod.

[0010] Furthermore, there is a through hole in the center of the valve sleeve top block and the zeroing screw, and the through holes are connected when the two are in close contact; when the zeroing screw on one side advances and the zeroing screw on the other side retreats, the screws push the valve sleeve gasket and the valve sleeve to move to one side, and the central connecting hole between the valve sleeve top block and the zeroing screw can make the cavity between the outer side of the valve sleeve and the end cover connected with the external atmosphere, avoiding the situation that when the seal between the gasket and the end cover is good, the movement of the valve sleeve top block causes vacuum or pressure increase in the inner cavity and the valve sleeve cannot move.

[0011] Furthermore, there are fuse holes at the ends of the zero adjustment screws on both sides. After the screws are tightened, they are locked with locking wires in time to ensure the stability of the zero position of the servo valve.

[0012] Furthermore, the pre-stage mainly includes a torque motor composed of upper and lower magnetic conductors, etc., an armature assembly composed of a spring tube, a feedback rod, etc., and an oil filter assembly.

[0013] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0014] 1. The servo valve zero position adjustment device can reasonably adjust the zero position of the entire valve without changing the original zero position of the servo valve pre-stage, which can effectively improve the matching with the system.

[0015] 2. The zero position adjustment device is located outside the valve body. There is no need to disassemble the entire valve. It is simple to operate and maintain, and it is more convenient for field maintenance of the servo valve.

[0016] 3. The regulating device tightens both sides of the valve sleeve, which is more conducive to the stability of the valve sleeve.

[0017] 4. The device adds an adjustment limit design to avoid damage to the servo valve during zero adjustment, which is more friendly to operators with little experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The utility model discloses a working principle diagram of a zero-position adjustable electro-hydraulic servo valve.

[0019] Among them, 1 is the pre-stage, 2 is the valve sleeve, 3 is the valve core, 4 is the valve sleeve top block, 5 is the zero adjustment screw, 6 is the limit pad, 7 is the slide valve stage, 8 is the end cover, 9 is the feedback rod, and 10 is the housing.

[0020] Figure 2 yes Figure 1 A partial schematic diagram of a bidirectional zero-position adjustment device. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0022] Example 1

[0023] The utility model specifically designs a flow-adjustable electro-hydraulic servo valve; the electro-hydraulic servo valve mainly includes a pre-stage and a slide valve stage; the pre-stage is arranged at the upper end of the slide valve stage, and the slide valve stage includes a valve core, a valve sleeve and a zero position adjustment mechanism; the difference from the conventional electro-hydraulic servo valve is the design of the zero position mechanism; in the specific servo valve structure, the valve sleeve top block 4 is located between the valve sleeve 2 and the end cover 8, the inner side of the valve sleeve top block 4 is tightly attached to the outer edge of the valve sleeve 2, and there is a conical groove on the outer side of the valve sleeve top block 4, and the head of the zero adjustment screw 5 presses the valve sleeve top block 4 inward in the conical groove. The end cover 8 is fixed to the end face of the housing 10, and the zero adjustment screw 5 passes through the threaded hole of the end cover 8. The feed amount of the valve sleeve top block 4 can be changed by adjusting the zero adjustment screws 5 on both sides, thereby adjusting the relative position of the valve sleeve 2 and the housing 10 and the pre-stage 1, and then adjusting the overall zero position of the servo valve. For different types of valve sleeves and housings, the maximum movement of the valve sleeve 2 can be limited by adjusting the thickness of the limit pad 6 to avoid excessive adjustment that causes the valve sleeve 2 and the housing 10 to shear the feedback rod 9, causing damage to the feedback rod 9. There is a through hole in the center of the valve sleeve top block 4 and the zero adjustment screw 5, and the through hole is connected when the two are close together. When the zero adjustment screw 5 on one side is fed forward and the zero adjustment screw 5 on the other side is retreated, the screw pushes the valve sleeve pad 4 and the valve sleeve 2 to move to one side, and the central connecting hole of the valve sleeve top block 4 and the zero adjustment screw 5 can make the cavity between the outside of the valve sleeve 2 and the end cover 8 connected to the external atmosphere, avoiding the situation that when the limit pad 6 and the end cover 8 are well sealed, the movement of the valve sleeve top block 4 causes vacuum or pressure increase in the inner cavity and the valve sleeve 2 cannot move. After zeroing, tighten the zeroing screw 5 with the specified torque to avoid deformation of the valve sleeve 2 caused by excessive pre-tightening force of the zeroing screws 5 on both sides; there are fuse holes at the ends of the zeroing screws 5 on both sides. After the screws are tightened, use the locking wire to lock them in time to ensure the stability of the servo valve zero position.

[0024] Compared with the traditional servo valve, the zero-position adjustable servo valve structure proposed in the utility model can reasonably adjust the zero position of the entire valve without changing the original zero position of the servo valve pre-stage, which can effectively improve the matching with the system. In addition, the adjustment device is located outside the valve body, and there is no need to disassemble the entire valve. The operation is simple, the maintenance is convenient, and it is more convenient for field maintenance of the servo valve. Compared with the existing servo valve zero position adjustment method, the adjustment device tightens the two sides of the valve sleeve, which is more conducive to the stability of the valve sleeve, and the adjustment limit design is added to avoid damage to the servo valve during the zero adjustment process, and the operation safety margin is high.

[0025] Finally, it should be noted that the above implementation methods or implementation cases are only used to illustrate the technical solution of the utility model, and any incomplete details are regarded as conventional technical means or common knowledge in the field; it should be understood that the protection scope of the utility model is not limited to the above specific implementation forms, and any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the utility model, and these modifications or substitutions should be covered within the protection scope of the utility model.

Claims

1. A zero-position adjustable electro-hydraulic servo valve, comprising a pre-stage and a slide valve stage; the pre-stage is arranged at the upper end of the slide valve stage, characterized in that: The sliding valve stage includes a valve core, a valve sleeve and a zero position adjustment mechanism; the zero position adjustment mechanism is arranged at both ends of the valve core; the zero position adjustment mechanism is composed of a valve sleeve top block and a zero adjustment screw; a valve sleeve top block is arranged between the two end surfaces of the valve sleeve and the end cover, the end cover is fixed to the end surface of the shell, and the zero adjustment screw passes through the threaded hole of the end cover. The feed amount of the valve sleeve top block can be changed by adjusting the zero adjustment screws on both sides, thereby adjusting the relative position of the valve sleeve and the shell and the pre-stage along the axial direction of the valve core, thereby adjusting the overall zero position of the servo valve.

2. A zero position adjustable electro-hydraulic servo valve as claimed in claim 1, characterized in that: A conical groove is arranged on the outer side of the valve sleeve top block, and the head of the zero adjustment screw presses the valve sleeve top block inwards in the conical groove.

3. A zero position adjustable electro-hydraulic servo valve as claimed in claim 1, characterized in that: The zero position adjustment mechanism further comprises a limit pad; for different types of valve sleeves and housings, the maximum movement of the valve sleeve can be limited by adjusting the thickness of the limit pad.

4. A zero position adjustable electro-hydraulic servo valve as claimed in claim 1, characterized in that: There is a through hole in the center of the valve sleeve top block and the zero adjustment screw, and the through hole is connected when the two are in close contact; when the zero adjustment screw on one side advances and the zero adjustment screw on the other side retreats, the screw pushes the valve sleeve gasket and the valve sleeve to move to one side, and the central connecting hole between the valve sleeve top block and the zero adjustment screw can make the cavity between the outer side of the valve sleeve and the end cover connected with the external atmosphere.

5. A zero-position adjustable electro-hydraulic servo valve as claimed in claim 4, characterized in that: There are fuse holes at the ends of the zero adjustment screws on both sides. After the screws are tightened, use the locking wire to lock them in time to ensure the stability of the servo valve zero position.

6. A zero-position adjustable electro-hydraulic servo valve as claimed in claim 1, characterized in that: The pre-stage comprises a torque motor composed of upper and lower magnetic conductors, an armature assembly composed of a spring tube and a feedback rod, and an oil filter assembly.

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