Position detection device for piston rod of hydraulic cylinder

Abstract

The utility model provides a position detection device for a piston rod of a hydraulic cylinder, which comprises a magnetic induction sensor arranged on the hydraulic cylinder body, a gap is arranged between the magnetic induction sensor and the piston rod in the hydraulic cylinder body, and a magnetic area and a non-magnetic area are alternately arranged on the piston rod. According to the utility model, the magnetic resistance of the magnetic induction sensor is changed by adopting the principle that the piston rod is pre-embedded in the magnetic induction area and different hysteresis effects of different materials, the induction signal is convenient for forming a phase difference between reference signals, and then the displacement of the piston rod of the hydraulic cylinder can be obtained through corresponding signal processing; the device is not affected by temperature, oil stains, metal and dust, a non-contact and non-wear installation mode is adopted, and when the piston rod is ejected at a high speed, detected data are real-time and accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulics, and particularly relates to a position detection device for a piston rod of a hydraulic cylinder. Background Art

[0002] Modern machinery has a high degree of automation and mechatronics integration, and it is often necessary to detect and control the position of the piston rod in the hydraulic cylinders of working devices, traveling devices, etc.

[0003] The forms of common displacement detection systems for piston rods are diverse. The displacement detection systems in the prior art include a wire-drawing displacement sensor and an external magnetic grating ruler method. The wire-drawing structure is affected by the stretching, thermal expansion and contraction, mechanical vibration, and back-and-forth pulling and wearing of the wire, and the accuracy is affected. For the external magnetic grating ruler, the external structure is complex, the jitter of the external structure causes errors, and there is also the problem of demagnetization of the magnetic grating, resulting in inaccurate data.

[0004] In actual use scenarios, in most cases, the signal sensor part is external. Its characteristics are simple structure, low cost, convenient maintenance, etc. However, the signal sensing part is easily damaged by collisions, moisture, corrosion, and temperature changes, so it is not suitable for working in harsh environments (such as mines, tunnels, and underwater operations).

[0005] Therefore, the prior art needs to be improved. Content of the Utility Model

[0006] In view of the deficiencies of the above-mentioned prior art, the utility model provides a position detection device for a piston rod of a hydraulic rod, which is not affected by temperature, oil stains, metals, and dust, adopts a non-contact and non-wearing installation method, and when the piston rod shoots out at high speed, the detected data is real-time and accurate.

[0007] In order to achieve the above object, the utility model adopts the following technical solutions:

[0008] A position detection device for a piston rod of a hydraulic cylinder includes a magnetic induction sensor arranged on a hydraulic cylinder body. There is a gap between the magnetic induction sensor and the piston rod in the hydraulic cylinder body. Magnetic regions and non-magnetic regions are alternately arranged on the piston rod.

[0009] Further, the magnetic induction sensor includes a PCB board, a magnet, and an iron sheet. The iron sheet is located between the magnet and the PCB board, and a magneto-sensitive element is arranged on the PCB board.

[0010] Further, non-magnetic materials are arranged in the non-magnetic regions.

[0011] Further, a positioning groove is arranged on the side surface of the magnetic induction sensor.

[0012] Furthermore, the magnetic induction sensor is provided with a thread for adjusting the distance between the magnetic induction sensor and the piston rod.

[0013] Furthermore, the gap between the magnetic induction sensor and the piston rod in the hydraulic cylinder body is 0.2mm-1mm.

[0014] Furthermore, the magnetic induction sensor is sealed by glue potting.

[0015] Furthermore, a mounting groove for mounting the magnetic induction sensor is provided on the hydraulic cylinder body.

[0016] Furthermore, the mounting groove is provided with a screw for fixing the magnetic induction sensor.

[0017] Furthermore, a magnetic shielding cover is arranged inside the magnetic induction sensor.

[0018] Compared with the prior art, the position detection device of the hydraulic cylinder piston rod provided by the utility model includes a magnetic induction sensor arranged on the hydraulic cylinder body, a gap is arranged between the magnetic induction sensor and the piston rod in the hydraulic cylinder body, and the piston rod is alternately provided with magnetic areas and non-magnetic areas. According to the utility model, the piston rod is pre-embedded with a magnetic induction area, and the magnetic resistance of the magnetic induction sensor is changed through different principles of hysteresis effect of different materials, so that the induction signal is convenient to form a phase difference between the reference signal, and then after corresponding signal processing, the displacement of the hydraulic cylinder piston rod can be obtained. The device is not affected by temperature, oil, metal and dust, and adopts a contactless and wear-free installation method. When the piston rod is ejected at high speed, the detected data is real-time and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of the installation of a position detection device for a hydraulic cylinder piston rod and the piston rod provided by the utility model.

[0021] Figure 2 This is a front view of the installation of the hydraulic cylinder piston rod position detection device and the piston rod provided by the utility model.

[0022] Figure 3 for Figure 1 A magnified schematic diagram of center A.

[0023] Figure 4 Partial assembly schematic diagram of the magnetic induction sensor of the position detection device for the hydraulic cylinder piston rod provided by the present utility model.

[0024] Figure 5 Assembly schematic diagram between the A-channel induction device and the B-channel induction device of the position detection device for the hydraulic piston rod provided by the present utility model and the piston rod.

[0025] Figure 6 Voltage output diagram when the piston rod of the position detection device for the hydraulic rod provided by the present utility model moves to the right.

[0026] Figure 7 Voltage output diagram when the piston rod of the position detection device for the hydraulic rod provided by the present utility model moves to the left.

[0027] Explanation of the attached drawing reference numerals:

[0028] Magnetic induction sensor - 1, piston rod - 2, magnetic region - 3, non-magnetic region - 4, PCB board - 5, magnet - 6, iron sheet - 7, positioning groove - 8, gap - 9, A-channel induction device - 10, B-channel induction device - 11. Detailed implementation manners

[0029] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant attached drawings. Embodiments of the present application are shown in the attached drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0031] In the present utility model, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present utility model and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation. Moreover, in addition to being able to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present utility model can be understood according to specific circumstances.

[0032] In addition, the terms "first", "second", etc. used in the present application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. When used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprising", "including" or "having", etc. specify the presence of the stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0033] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0034] In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions results in contradictions or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0035] Such as Figure 1 , Figure 2 and Figure 3As shown, the position detection device of the hydraulic cylinder piston rod provided by the utility model includes a magnetic induction sensor 1 arranged on the hydraulic cylinder body, and a gap 9 is arranged between the magnetic induction sensor 1 and the piston rod 2 in the hydraulic cylinder body. The gap can prevent the piston rod 2 from rubbing and damaging the magnetic induction sensor 1. Magnetic areas 3 and non-magnetic areas 4 are alternately arranged on the piston rod 2. It can be understood that magnetic materials and non-magnetic materials are alternately arranged on the piston rod 2, that is, magnetic materials and non-magnetic materials are alternately pre-embedded.

[0036] It should be noted that when the hydraulic cylinder is working, the piston rod 2 moves, and the magnetic induction sensor 1 has a magnet 6 that can magnetize the piston rod 2. Since magnetic materials and non-magnetic materials are alternately arranged on the piston rod 2, different materials will cause the magnetic resistance of the magnetic induction sensor 1 to change, that is, a phase difference is formed between the signal sensed by the magnetic induction sensor 1 and the reference signal. After corresponding signal processing, the displacement of the piston rod 2 can be obtained.

[0037] Compared with the prior art, in the technical solution of the utility model, a piston rod 2 is pre-buried with a magnetic induction area, and through the different principles of the hysteresis effect of different materials, the magnetic resistance of the magnetic induction sensor 1 is changed, and the induction signal is convenient for forming a phase difference between the reference signal, and then after corresponding signal processing, the displacement of the hydraulic cylinder piston rod 2 can be obtained. The device is not affected by temperature and oil, metal and dust, and can be used in different water temperatures and corresponding water vapor environments. It can operate reliably even in harsh environments, and the device adopts a contactless and wear-free installation method. When the piston rod 2 is ejected at high speed, the detected data is real-time and accurate.

[0038] Furthermore, if Figure 4 As shown, the magnetic induction sensor 1 includes a PCB board 5, a magnet 6 and an iron sheet 7. The iron sheet 7 is located between the magnet 6 and the PCB board. A magnetic sensitive element is arranged on the PCB board 5.

[0039] It can be understood that when the hydraulic cylinder is working, the piston rod 2 extends outward. At this time, the magnet 6 can magnetize the iron sheet 7, and then further magnetize the magnetic area 3 on the piston rod 2. According to the different hysteresis effects of the magnetic area 3 and the non-magnetic area 4, the information is collected by the magnetic sensitive element and transmitted to the PCB board 5, and the corresponding data signal processing is performed to obtain the displacement of the piston rod 2.

[0040] like Figure 5As shown, the specific principle that the magnetic sensitive element can detect the movement amount of the piston rod 2 is as follows: the magnetic sensitive element includes an A-path induction device 10 and a B-path induction device, and there is a certain distance between the A-path induction device 10 and the B-path induction device. The magnetic lines of force of the magnet 6 pass through the PCB board 5 to reach the surface of the piston rod 2. When the piston rod 2 moves to the right, since the position of the A-path induction device 10 is closer to the front of the B-path induction device 11, the A-path induction device 10 first senses the reflected magnetic strength data, and the B-path induction device 11 senses the reflected magnetic strength data later. At this time, the output voltage diagram of the A-path induction device 10 and the B-path induction device 11 is as shown in Figure 6 On the contrary, Figure 7 As shown, if the piston rod 2 moves to the left, the B-path sensing device 11 senses data earlier than the A-path sensing device 10, and the direction of movement of the piston rod 2 can be determined by utilizing the phase difference principle, and the sine wave is converted into a square wave pulse. After counting the pulses, the distance between the magnetic area 3 and the non-magnetic area 4 pre-embedded on the piston rod 2 is calculated, and the distance moved by the piston rod 2 is obtained.

[0041] It should be noted that the performance parameter resolution of the magnetic induction sensor 1 is 0.5mm-3mm, the signal sampling frequency is 5MHZ, the operating temperature range is -20℃-120℃, and the signal processing delay of the magnetic induction sensor 1 is 0.01 microseconds, which can ensure the sensitivity of mechanical closed-loop control, and the magnetic induction sensor 1 can meet the requirements from 100m / s high-speed control of variable-speed stamping machinery to low-speed control of metallurgical forging equipment below 0.01m / s of the servo controller.

[0042] Furthermore, the non-magnetic region 4 is provided with a non-magnetic material, preferably, the non-magnetic material is a copper ring, and the magnetic region can be magnetized by the magnetic induction sensor 1, and then the displacement of the piston rod 2 can be obtained through further signal processing based on the phase difference between the signal of the magnetic region 3 and the non-magnetic region 4 sensed by the sensor and the reference signal.

[0043] Furthermore, a positioning groove 8 is provided on the side of the magnetic induction sensor 1, and the positioning groove 8 can limit the installation direction of the magnetic induction sensor 1, and can avoid the magnetic induction sensor 1 from failing to sense data due to an incorrect installation angle of the magnetic induction sensor 1.

[0044] Furthermore, a thread for adjusting the distance between the magnetic induction sensor 1 and the piston rod 2 is provided on the magnetic induction sensor 1. When installing the magnetic induction sensor 1, the magnetic induction sensor 1 can be installed at an appropriate position through the thread, ensuring that the magnetic induction sensor 1 can work within a normal distance range without being rubbed and worn by the piston rod 2.

[0045] Furthermore, the gap 9 between the magnetic induction sensor 1 and the piston rod 2 in the hydraulic cylinder body is 0.2 mm - 1 mm. Preferably, the gap 9 between the magnetic induction sensor 1 and the piston rod 2 in the hydraulic cylinder body is 0.4 mm. It should be noted that for the existing injection sensors of die-casting machines, the designed distance between the sensor and the injection rod is only 0.3 mm. During the movement of the injection rod, the head of the sensor is easily worn, thus damaging the internal components. The existing sensors use a square magnet 6, and then an iron sheet 7 is used to conduct the magnetic force to reach the surface of the injection rod through the back of the detection chip. If the magnetic force is too strong, the induction will fail; if the magnetic force is weak, the detected distance will be too short. During the production process of the die-casting machine, the injection rod expands and contracts due to heat, and there are slight bending deformations. The too-small distance between the sensor and the injection rod causes frequent friction between the injection rod and the sensor, resulting in frequent damage to the sensor. However, with the gap 9 of 0.4 mm adopted in this application, it can ensure that the magnetic induction sensor 1 can work within a normal distance range without being rubbed and worn by the piston rod 2.

[0046] Furthermore, the magnetic induction sensor 1 is sealed with glue and has the functions of water and oil resistance, and can also be used in different water levels, that is, in the corresponding water vapor environment, and can operate reliably even in a harsh environment.

[0047] Furthermore, an installation groove for installing the magnetic induction sensor 1 is provided on the hydraulic cylinder body. Preferably, a screw for fixing the magnetic induction sensor 1 is provided on the installation groove, and the screw can prevent the magnetic induction sensor 1 from loosening during installation in the installation groove, ensuring that the magnetic induction sensor 1 can work normally.

[0048] Furthermore, a magnetic shielding cover is provided inside the magnetic induction sensor 1, and the magnetic shielding cover can effectively shield external electromagnetic interference, ensuring the accuracy of the detection data of the magnetic induction sensor 1.

[0049] In summary, the position detection device for the piston rod of the hydraulic cylinder provided by the utility model, the positioning groove can avoid the installation angle of the magnetic induction sensor being incorrect, resulting in the magnetic induction sensor not being able to sense data. Through the thread, the magnetic induction sensor can be installed in a suitable position to ensure that the magnetic induction sensor can work within a normal distance range without being rubbed and worn by the piston rod. The magnetic induction sensor adopts glue sealing, has the function of water and oil resistance, and can also be used in different water levels, that is, corresponding water vapor environments. The magnetic shielding cover can effectively shield external electromagnetic interference to ensure the accuracy of the data detected by the magnetic induction sensor. According to the utility model, the piston rod is pre-buried with a magnetic induction area, and the magnetic resistance of the magnetic induction sensor is changed through the different principles of the hysteresis effect of different materials. The induction signal is convenient for the reference signal to form a phase difference, and then after corresponding signal processing, the displacement of the piston rod of the hydraulic cylinder can be obtained. The device is not affected by temperature, oil, metal and dust, and adopts a contactless and wear-free installation method. When the piston rod is ejected at high speed, the detected data is real-time and accurate.

[0050] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all belong to the protection scope of the utility model.

Claims

1. A position detection device for a hydraulic cylinder piston rod, characterized in that: The invention comprises a magnetic induction sensor (1) arranged on a hydraulic cylinder body, a gap (9) being arranged between the magnetic induction sensor (1) and a piston rod (2) in the hydraulic cylinder body, and a magnetic area (3) and a non-magnetic area (4) being alternately arranged on the piston rod (2).

2. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: The magnetic induction sensor (1) comprises a PCB board (5), a magnet (6) and an iron sheet (7); the iron sheet (7) is located between the magnet (6) and the PCB board (5); and a magnetic sensitive element is provided on the PCB board (5).

3. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: The non-magnetic area (4) is provided with a non-magnetic material.

4. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: A positioning groove (8) is provided on the side of the magnetic induction sensor (1).

5. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: The magnetic induction sensor (1) is provided with a thread for adjusting the distance between the magnetic induction sensor (1) and the piston rod (2).

6. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: The gap (9) between the magnetic induction sensor (1) and the piston rod (2) in the hydraulic cylinder body is 0.2 mm-1 mm.

7. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: The magnetic induction sensor (1) is sealed by glue potting.

8. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: The hydraulic cylinder body is provided with a mounting groove for mounting the magnetic induction sensor (1).

9. The position detection device for the hydraulic cylinder piston rod according to claim 8, characterized in that: The mounting groove is provided with a screw for fixing the magnetic induction sensor (1).

10. The position detection device for the hydraulic cylinder piston rod according to claim 1, characterized in that: A magnetic shielding cover is arranged inside the magnetic induction sensor (1).

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