Hydraulic valve with non-contact valve core position detection function and control method thereof

Abstract

The invention relates to a hydraulic valve with a non-contact valve element position detection function and a control method of the hydraulic valve. The hydraulic valve comprises a valve body, a valve element, a laser displacement sensor, a pressure sensor and a driving unit. The valve element is arranged in the valve body, one end of the valve element is connected with the driving unit, the other end of the valve element is provided with a detection part, the laser displacement sensor is arranged in front of the detection part, the detection part moves within the detection range of the laser displacement sensor, and the laser displacement sensor emits laser towards the end face of the detection part and receives reflected light of the end face of the valve element at a certain angle. The valve body is provided with a working oil port, an oil inlet and an oil return port in the axial direction, the working oil port is communicated with an external load, and the pressure sensor is arranged at the working oil port. Compared with the prior art, accurate, reliable and efficient detection of the displacement of the valve element is achieved through the non-contact laser displacement sensor, the on-off state, the flow size and the flow direction of a valve oil port are conveniently controlled, and accurate control and reliable operation of a whole hydraulic system are facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydraulic valves, in particular to a hydraulic valve with non-contact valve core position detection and a control method thereof. BACKGROUND

[0002] In a hydraulic transmission and control system, a hydraulic control valve is a core precision component for controlling the operation of various mechanisms in the entire hydraulic system, and its performance directly affects the reliability, control accuracy and service life of the entire system. The displacement of the valve core in the valve body is a key parameter, which is directly related to the on-off state, flow size and direction of the control valve oil port, and further affects the precise control of the actuator action. Therefore, accurate, reliable and efficient detection of the valve core displacement is of great significance for performance verification, quality control and fault diagnosis of valve products, as well as accurate control and reliable operation of the entire hydraulic system.

[0003] At present, in a hydraulic transmission and control system, a hydraulic control, an electric control or a mechanical operating lever is generally used to drive the valve core to move. In some high-precision applications, a stepper motor or a servo motor is used to control the movement of the valve core, and the valve core position is calculated by the input parameters of the motor. The stepper motor confirms the number of motor turns by the number of input pulses, and then determines the displacement of the valve core by multiplying the number of motor turns by the lead of the screw. However, in actual application, due to load changes or motor matching, the stepper motor may lose steps, and the displacement of the valve core cannot be accurately calculated by the number of pulses at this time. This scheme has certain uncertainty. When a servo motor is used to drive the valve core to move, the servo motor shaft encoder is mainly used to measure the driving angle of the servo motor in real time, and the specific displacement of the valve core is confirmed by a PID closed-loop control algorithm. This scheme needs to be optimized and set according to the specific load inertia and rigidity most of the time. Improper parameter setting may cause slow system response, vibration or positioning overshoot, affecting dynamic accuracy, and also has certain defects. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a hydraulic valve with non-contact valve core position detection and a control method thereof, which realizes accurate detection of the valve core position.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A hydraulic valve with non-contact valve core position detection, comprising a valve body, a valve core, a laser displacement sensor, a pressure sensor and a driving unit.

[0007] The valve core is arranged in the valve body, one end of the valve core is connected with the driving unit, the other end is provided with a detection part, the laser displacement sensor is arranged in front of the detection part, the detection part moves in the detection range of the laser displacement sensor, the laser displacement sensor emits laser towards the end face of the detection part, and the reflected light of the valve core end face is received at a certain angle.

[0008] The valve body is provided with a working oil port, an oil inlet and an oil return port in the axial direction, the working oil port is communicated with an external load, the oil inlet is communicated with an oil source, and the oil return port is communicated with an oil return tank, and the pressure sensor is arranged at the working oil port.

[0009] Further, a first end cover and a second end cover are arranged at both ends of the valve body respectively, and the detection part extends from the first end cover.

[0010] Further, the laser displacement sensor is mounted on the first end cover through a bracket.

[0011] Further, the bracket is in a bent shape, one end of the bracket is fixed on the first end cover, and the other end is mounted with the laser displacement sensor, so that the laser emitting unit and the optical receiving unit of the laser displacement sensor are both directed towards the end face of the detection part.

[0012] Further, the detection part is a columnar body extending outwards from the end face of the valve core to the first end cover, and the first end cover is provided with a sealing element at the extension outlet of the detection part.

[0013] Further, the laser displacement sensor adopts a visible red light diffuse reflection ranging principle.

[0014] Further, the natural object measurement linearity of the laser displacement sensor is ±6um, the repeat accuracy is 0.1um, and the response time is 12.5us.

[0015] Further, a controller is further included, and the controller is connected with the laser displacement sensor, the pressure sensor, the driving unit and the detection unit of the external load respectively.

[0016] Further, the hydraulic valve is a slide valve type three-position four-way structure.

[0017] A control method of a hydraulic valve with non-contact valve core position detection, the control method of the hydraulic valve with non-contact valve core position detection, the control method comprises:

[0018] Driving the valve core of the hydraulic valve to move through the driving unit according to the target opening degree information;

[0019] The displacement information of the valve core and the pressure information of the hydraulic valve working oil port are acquired, the flow rate of the valve port opening is obtained by calculation, and then the flow rate derivation position of the external load connected with the working oil port is obtained;

[0020] The flow rate derivation position is compared with the target position of the external load, and the control instruction is dynamically adjusted according to the comparison result, so that the valve core is always in the correct position.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1、The present application realizes accurate, reliable and efficient detection of the displacement of the valve core through a non-contact laser displacement sensor, which is convenient for controlling the on-off state, flow size and direction of the valve oil port, and is beneficial to accurate control and reliable operation of the entire hydraulic system.

[0023] 2、The present application realizes accurate detection of the valve core position and accurate distribution of the flow rate, so that the speed and force of the actuator (oil cylinder, motor) can be accurately controlled in actual use, avoiding a large amount of throttling loss and heat loss caused by throttling or overflow to adjust the speed in the traditional system, prolonging the service life of the hydraulic oil and the sealing element, and reducing the load of the cooling system.

[0024] 3、The valve core position detection function of the present application can realize fault diagnosis of the hydraulic system, such as immediate alarm when the instruction is issued but the valve core position does not change, prompting the valve core to be stuck, and avoiding greater failure.

[0025] 4、The change trend of the valve core response time can be monitored by the present application to predict the wear condition of the valve and realize predictive maintenance and other functions. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structure schematic view of the hydraulic valve with non-contact valve core position detection in the embodiment;

[0027] Figure 2 It is a laser displacement sensor ranging size matching schematic view in the embodiment.

[0028] REFERENCE SIGNS:

[0029] 1-valve body part; 11-second end cover; 12-valve core; 13-valve body; 14-first end cover; 15-sealing element; 16-detection part; 2-sensor part; 21-mounting bolt; 22-bracket; 23-laser displacement sensor; 24-mounting screw; 25-wiring terminal; A-first working oil port; B-second working oil port; P-oil inlet; T-oil return port. DETAILED DESCRIPTION

[0030] The application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0031] As shown in Figure 1 The application provides a hydraulic valve with non-contact valve core position detection, which comprises a valve body part 1 and a sensor part 2, and specifically comprises a valve body 13, a valve core 12, a laser displacement sensor 23, a pressure sensor and a driving unit. The valve core 12 is arranged in a valve core hole of the valve body 13, one end of the valve core 12 is connected with the driving unit, the driving mode can be hydraulic control, electric control or mechanical mode, and the other end is provided with a detection part 16 for laser position detection. The laser displacement sensor 23 is arranged in front of the detection part 16, and the detection part 16 moves in the detection range of the laser displacement sensor 23. The valve body 13 is provided with a working oil port, an oil inlet port P and a return oil port T in the axial direction, the working oil port is in communication with an external load, which is generally an actuating mechanism such as a hydraulic cylinder or a hydraulic motor, the oil inlet port P is in communication with an oil source, the return oil port T is in communication with a return oil tank, and the pressure sensor is arranged at the working oil port. In the embodiment, neither the driving unit nor the pressure sensor is shown. Figure 1

[0032] In the embodiment, the two ends of the valve body 13 are respectively provided with a first end cover 14 and a second end cover 11, and the detection part 16 extends out of the first end cover 14. The detection part 16 is specifically a columnar body extending out of the end face of the valve core 12 towards the outside of the first end cover 14, and the first end cover 14 is provided with a sealing element 15 at the outlet of the detection part 16.

[0033] In the embodiment, the laser displacement sensor 23 is installed on the first end cover 14 through a bracket 22. The bracket 22 is in a bent shape, one end of the bracket 22 is fixed on the first end cover 14 through a mounting bolt 21, and the other end fixes the laser displacement sensor 23 through a mounting screw 24, so that the emission end face of the laser displacement sensor 23 faces the end face of the detection part 16. The laser displacement sensor 23 transmits data to a working unit with data acquisition and processing function through a wiring terminal 25.

[0034] In the embodiment, the hydraulic valve is a slide valve type three-position four-way structure, and the working oil port comprises a first working oil port A and a second working oil port B, which are connected with actuating elements such as two cavities of a hydraulic cylinder or two interfaces of a hydraulic motor. The hydraulic valve changes the axial position of the valve core 12 in the valve body 13 through an external driving force (electric, hydraulic, pneumatic or manual), dynamically switches the communication relationship between the four main oil ports P, T, A and B by the cooperation of the shoulder and the groove on the valve core 12, and thereby controls the movement direction (forward / backward) and the stop state of the actuating mechanism.

[0035] ​The laser displacement sensor 23 includes a laser emitter and an optical receiving unit, both facing the end face of the detection unit 16, such as... Figure 2 As shown, the laser emitter emits a laser beam toward the end face of the detection unit 16, and the reflected light from the end face of the detection unit 16 is reflected at a certain angle α into the optical receiving unit. During installation, the distance between the emitting end face of the laser displacement sensor 23 and the end face of the valve core 12 is L0, the left and right limit positions of the valve core 12 are L1 and L2 respectively, and the movement ranges L1 and L2 of the detection unit 16 extending from the right end of the valve core 12 must be within the measurable range of the laser displacement sensor 23.

[0036] In this embodiment, the laser displacement sensor 23 adopts the visible red light diffuse reflection ranging principle, with a linearity of ±6µm for measuring natural objects, a repeatability of 0.1µm, a response time of 12.5µs, an IP67 enclosure protection rating, and a current output signal of 4~20mA.

[0037] In one embodiment, the hydraulic valve further includes a controller, which is connected to the laser displacement sensor 23, the pressure sensor, the drive unit, and the detection unit of the external load. The controller may include an embedded processor or a digital controller; in specific implementations, it may be a separate control unit or integrated into the drive unit.

[0038] During operation, the oil inlet P port is connected to the hydraulic pump outlet oil source. The control terminal (such as a handle) sends a command to the drive unit of valve core 12. Under the action of control pressure oil or mechanical lever, valve core 12 will move left or right. At this time, the pressure oil at port P flows to the actuator through working oil ports A / B, and the return oil flows back to the hydraulic oil tank through return oil port T. Simultaneously, when valve core 12 moves left or right, laser displacement sensor 23 calculates the time required for the light to travel to and from the source and uses the speed of light formula to obtain an accurate distance value. Since the response time of the laser sensor is 12.5 μs, multiplying it by the speed of light calculates the displacement change of valve core 12, thus achieving accurate detection of valve core 12 displacement.

[0039] For hydraulic systems, by using pressure sensors installed at the A / B ports of the main valve and combining them with the displacement of the valve core 12, the flow rate at a specific valve opening can be calculated according to the valve flow rate formula. This allows the actual position of the actuator to be determined. The controller can then compare the actual position of the actuator calculated by the flow rate with the target position and dynamically adjust the control commands to ensure that the valve core 12 is always in the correct position.

[0040] This application also proposes a control method for a hydraulic valve with non-contact valve core position detection, used to control the hydraulic valve with non-contact valve core position detection involved in the above embodiments and possible implementations. The method includes:

[0041] The hydraulic valve drives the spool 12 to move through the driving unit according to the target opening degree information;

[0042] The displacement information of the spool 12 and the pressure information of the hydraulic valve working oil port are acquired, the flow rate when the valve port is opened is calculated, and the flow rate derivation position of the external load connected to the working oil port, i.e., the actual position, is obtained;

[0043] The flow rate derivation position is compared with the target position of the external load, and the control instruction is dynamically adjusted according to the comparison result, so that the spool 12 is always in the correct position.

[0044] In the embodiment, each displacement information of the spool 12 corresponds to a valve body flow area, and the flow rate when the valve port is opened is obtained according to the following formula:

[0045]

[0046] Wherein, Q is the current flow rate of the hydraulic valve, C is the flow rate coefficient, p is the density of the hydraulic oil, ΔP is the pressure difference between the relative pressure of the first working oil port A and the oil inlet port P and the relative pressure of the second working oil port B and the oil inlet port P, and A is the flow area of the valve body 13 corresponding to the current displacement information.

[0047] The position of the spool 12 of the hydraulic valve is accurately controllable, so that the flow rate is accurately distributed, and the speed and force of the actuator (cylinder, motor) can be accurately controlled in actual use, avoiding a large amount of throttling loss and heat loss generated by adjusting the speed through throttling or overflow in the traditional system, prolonging the service life of the hydraulic oil and the sealing element 15, and reducing the load of the cooling system. In addition, the position detection of the spool 12 can realize hydraulic system fault diagnosis and predictive maintenance, such as no change in the position of the spool 12 when the instruction is issued, the system can immediately alarm and prompt that the spool 12 is stuck, avoiding greater failure, and the wear condition of the valve can be predicted by monitoring the change trend of the response time of the spool 12, and the functions of predictive maintenance, etc.

[0048] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0049] In addition, the terms "first", "second", etc. are used herein only to describe different instances, and do not imply or suggest relative importance or a number of the technical features indicated. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0050] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0052] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0053] The above describes the preferred embodiments of the present application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art according to the concept of the present application shall be within the protection scope determined by the claims.

Claims

1. A hydraulic valve with non-contact valve core position detection, characterized in that, Includes valve body, valve core, laser displacement sensor, pressure sensor and drive unit; The valve core is disposed in the valve body. One end of the valve core is connected to the drive unit, and the other end is provided with a detection part. The laser displacement sensor is disposed in front of the detection part. The detection part moves within the detection range of the laser displacement sensor. The laser displacement sensor emits laser light toward the end face of the detection part and receives the reflected light from the end face of the valve core at a certain angle. The valve body is provided with a working oil port, an oil inlet, and a return oil port in its axial direction. The working oil port is connected to an external load, the oil inlet is connected to an oil source, and the return oil port is connected to a return oil tank. The pressure sensor is located at the working oil port.

2. The hydraulic valve with non-contact valve core position detection according to claim 1, characterized in that, It also includes a first end cap and a second end cap respectively disposed at both ends of the valve body, with the detection part extending from the first end cap.

3. The hydraulic valve with non-contact valve core position detection according to claim 2, characterized in that, The laser displacement sensor is mounted on the first end cap via a bracket.

4. The hydraulic valve with non-contact valve core position detection according to claim 3, characterized in that, The bracket is bent, with one end fixed to the first end cap and the other end equipped with the laser displacement sensor, such that both the laser emitting unit and the optical receiving unit of the laser displacement sensor face the end face of the detection unit.

5. The hydraulic valve with non-contact valve core position detection according to claim 2, characterized in that, The detection part is a columnar body extending outward from the end face of the valve core to the first end cover, and the first end cover is provided with a sealing element at the protrusion of the detection part.

6. The hydraulic valve with non-contact valve core position detection according to claim 1, characterized in that, The laser displacement sensor uses the visible red light diffuse reflection ranging principle.

7. The hydraulic valve with non-contact valve core position detection according to claim 1 or 6, characterized in that, The laser displacement sensor has a linearity of ±6µm for measuring natural objects, a repeatability of 0.1µm, and a response time of 12.5µs.

8. The hydraulic valve with non-contact valve core position detection according to claim 1, characterized in that, It also includes a controller, which is connected to the laser displacement sensor, pressure sensor, drive unit and external load detection unit respectively.

9. The hydraulic valve with non-contact valve core position detection according to claim 1, characterized in that, The hydraulic valve is a three-position four-way spool valve.

10. A control method for a hydraulic valve with non-contact valve core position detection, characterized in that, The control method, applied to the hydraulic valve with non-contact valve core position detection as described in any one of claims 1 to 9, comprises: The valve core of the hydraulic valve is driven to move by the drive unit according to the target opening information; Obtain the displacement information of the valve core and the pressure information of the hydraulic valve working port, calculate the flow rate when the valve port is open, and then obtain the flow rate derivation position of the external load connected to the working port. The flow rate derivation position is compared with the target position of the external load, and the control command is dynamically adjusted according to the comparison result to ensure that the valve core is always in the correct position.

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