Piston position detection device of oil cylinder

Abstract

The utility model relates to a piston position detection device of an oil cylinder, and belongs to the technical field of oil cylinder equipment. Comprising a conduit, a pull rod, a proximity switch, a driving wheel, an encoder and a controller, a pull rod is slidably mounted in the guide pipe, a detection piece is arranged on the pull rod and extends outwards, and a proximity switch matched with the detection piece for use is arranged on the guide pipe; a driving wheel is rotationally mounted on the pull rod, and the circumferential surface of the driving wheel abuts against the inner side surface of the guide pipe; an encoder is arranged on the pull rod, a detection wheel is arranged on a shaft of the encoder, the outer circumferential face of the detection wheel abuts against the outer circumferential face of the driving wheel, and the proximity switch and the encoder are connected with a controller. Rotation of the detection wheel is detected through the encoder, so that the specific extension amount of the piston is judged, continuous detection of the position of the piston can be achieved, use is more convenient, meanwhile, when the oil cylinder runs to the limit state, the oil cylinder can be detected by the proximity switch and compared with a result obtained through detection of the encoder, and the accuracy of the detection result is ensured.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder equipment technology, and in particular to a piston position detection device for hydraulic cylinders. Background Technology

[0002] Reciprocating hydraulic cylinders are widely used in various fields. By using a directional valve fixed on the cylinder, the medium on both sides of the piston is filled and released, and the high-pressure chamber and low-pressure chamber are switched, thereby controlling the reciprocating motion of the piston. Among these, accurate detection of piston position information is a prerequisite for executing the hydraulic cylinder action, but the existing piston position information detection is not accurate enough.

[0003] For example, CN206770319U discloses a piston position detection device for a hydraulic cylinder. By setting multiple proximity switches, the piston position is detected. When the piston moves to the position between two adjacent proximity switches, it cannot be accurately detected. Therefore, the piston position information detection is discontinuous and the detection result is inaccurate. Utility Model Content

[0004] To solve or partially solve the problems existing in related technologies, this utility model provides a piston position detection device for hydraulic cylinders, aiming to solve the technical problem of discontinuous data obtained by existing piston position detection devices when detecting piston position.

[0005] The piston position detection device for a hydraulic cylinder described above includes a guide tube, a pull rod, a proximity switch, a drive wheel, an encoder, and a controller;

[0006] The conduit is fixedly installed on the cylinder body of the hydraulic cylinder. A pull rod is slidably installed inside the conduit. One end of the pull rod is fixedly connected to the piston rod of the hydraulic cylinder, and the other end is provided with a detection plate. A clearance hole is opened on the side of the conduit, and the detection plate extends outward from the clearance hole. Two proximity switches are provided on the conduit to cooperate with the detection plate.

[0007] When the piston rod of the hydraulic cylinder is fully extended, the detection piece is detected by one of the proximity switches; when the piston rod of the hydraulic cylinder is fully retracted, the detection piece is detected by the other proximity switch.

[0008] A drive wheel is rotatably mounted on the pull rod, and the circumferential surface of the drive wheel abuts against the inner surface of the guide tube; an encoder is provided on the pull rod, and a detection wheel is provided on the shaft of the encoder, and the outer circumferential surface of the detection wheel abuts against the outer circumferential surface of the drive wheel, so that the drive wheel can drive the detection wheel to rotate.

[0009] The proximity switch and the encoder are connected to the controller.

[0010] In some designs, the pull rod is provided with a groove, the groove is arc-shaped, the center of which is on the shaft of the encoder, a slider is slidably mounted in the groove, and a spring is provided between the slider and one end of the groove;

[0011] The drive wheel is rotatably mounted on the slider.

[0012] In some designs, both the drive wheel and the detection wheel are gears.

[0013] The inner wall of the conduit is provided with a rack that meshes with the drive wheel.

[0014] In some designs, the pull rod has mounting holes, and the drive wheel and the detection wheel are installed in the mounting holes.

[0015] In some designs, a traveling wheel is rotatably mounted on the pull rod, and the pull rod contacts the side wall of the conduit through the traveling wheel.

[0016] The technical solution provided by this utility model can include the following beneficial effects:

[0017] This application uses an encoder to detect the rotation of the detection wheel, thereby determining the specific extension amount of the piston. This enables continuous detection of the piston position, making it more convenient to use. At the same time, when the hydraulic cylinder reaches its limit, it can be detected by a proximity switch, and the results are compared with those obtained from the encoder to ensure the accuracy of the detection results.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the present invention. Attached Figure Description

[0019] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.

[0020] Figure 1 This is a schematic diagram of the assembly of the detection device and the hydraulic cylinder shown in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the detection device shown in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the assembly of the drive wheel and the detection wheel of the detection device shown in an embodiment of the present invention;

[0023] Figure 4 This is another assembly schematic diagram of the drive wheel and detection wheel of the detection device shown in this embodiment of the utility model;

[0024] Figure label:

[0025] 1. Conduit; 11. Clearance hole; 2. Pull rod; 21. Detector plate; 22. Slide groove; 23. Slider; 24. Spring; 25. Mounting hole; 3. Proximity switch; 4. Drive wheel; 5. Encoder; 6. Controller; 7. Detection wheel; 8. Rack; 9. Traveling wheel. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0027] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this application provides a piston position detection device for a hydraulic cylinder, including a conduit 1, a pull rod 2, a proximity switch 3, a drive wheel 4, an encoder 5, and a controller 6; the pull rod 2 is rectangular and made of steel bar, and the conduit 1 is made of square steel pipe. In some specific embodiments, the cross interface of the conduit 1 is roughly U-shaped and the end is slightly bent inward, or other shapes that can define the direction of movement of the pull rod 2.

[0028] The conduit 1 is fixedly installed on the cylinder body of the hydraulic cylinder. Specifically, a screw can be passed through the conduit 1 and threaded into the cylinder body to securely connect the conduit 1 to the cylinder body, or a clamp or similar device can be used to fix the conduit 1 to the cylinder body. A pull rod 2 is slidably installed inside the conduit 1. Specifically, the pull rod 2 can slide along the length of the conduit 1. One end of the pull rod 2 is fixedly connected to the piston rod of the hydraulic cylinder, so that when the hydraulic cylinder extends, the pull rod 2 can move with the piston rod. Specifically, the end of the pull rod 2 is connected to the mounting pin of the piston rod. The other end of the pull rod 2 is provided with a detection piece 21. A clearance hole 11 is opened on the side of the conduit 1. The length of the clearance hole 11 matches the shape of the hydraulic cylinder. The detection piece 21 extends outward from the clearance hole 11. The conduit 1 is provided with a proximity switch 3 that works with the detection piece 21. There are two proximity switches 3, one located at the top of the clearance hole 11 and the other located at the bottom of the clearance hole 11. The proximity switch 3 is connected to the controller 6.

[0029] When the hydraulic cylinder operates, if the piston rod is fully extended, the detection piece 21 is detected by one of the proximity switches 3 (the upper proximity switch 3), which sends a signal. Upon receiving the signal, the controller 6 determines that the hydraulic cylinder has extended to its limit. If the piston rod is fully retracted, the detection piece 21 is detected by the other proximity switch 3 (the lower proximity switch 3), which sends a signal. Upon receiving the signal, the controller 6 determines that the hydraulic cylinder has retracted to its limit. In this way, the controller 6 can accurately determine the extension and retraction limits of the hydraulic cylinder, thereby improving the safety of the hydraulic cylinder operation.

[0030] A drive wheel 4 is rotatably mounted on the pull rod 2. The circumferential surface of the drive wheel 4 abuts against the inner surface of the conduit 1. When the pull rod 2 moves, it drives the drive wheel 4 to move, thereby causing the drive wheel 4 to roll on the inner wall of the conduit 1. An encoder 5 is provided on the pull rod 2. A detection wheel 7 is provided on the shaft of the encoder 5. The outer circumferential surface of the detection wheel 7 abuts against the outer circumferential surface of the drive wheel 4, so that the drive wheel 4 can drive the detection wheel 7 to rotate. The encoder 5 is connected to the controller 6.

[0031] When the piston rod of the hydraulic cylinder moves, it drives the pull rod 2 to move. The pull rod 2 drives the drive wheel 4 to roll. The rotating drive wheel 4 then drives the detection wheel 7 to rotate, thereby driving the shaft of the encoder 5 to rotate. The encoder 5 transmits relevant signals to the controller 6. The controller 6 obtains the extension amount of the pull rod 2 based on the size of the drive wheel 4 and the detection wheel 7, and thus obtains the extension amount of the piston of the hydraulic cylinder, which is beneficial for the precise control of the extension amount of the hydraulic cylinder.

[0032] Note: The rotation angle of the detection wheel 7 can be obtained through the encoder 5, and the radius of the detection wheel 7 can be obtained by measurement. Therefore, the arc length at the corresponding rotation angle is the extension of the piston rod.

[0033] In some specific implementations, such as Figure 3 As shown, the pull rod 2 is provided with a slide groove 22, which is arc-shaped and the center of the circle is on the shaft of the encoder 5. A slider 23 is slidably installed in the slide groove 22. A spring 24 is provided between the slider 23 and one end of the slide groove 22. The spring 24 drives the slider 23 to move downward. The drive wheel 4 is rotatably installed on the slider 23.

[0034] Thus, under the elastic force of spring 24, slider 23 rotates counterclockwise, thereby pressing drive wheel 4 tightly against the inner wall of guide tube 1, effectively avoiding slippage caused by insufficient contact between drive wheel 4 and inner wall of guide tube 1 when pull rod 2 moves, and effectively improving the accuracy of piston rod position detection.

[0035] In this embodiment, the pull rod 2 has a mounting hole 25, and the drive wheel 4 and the detection wheel 7 are installed in the mounting hole 25, so that the drive wheel 4 and the detection wheel 7 are clamped, avoiding radial deflection of the drive wheel 4 and the detection wheel 7, and effectively ensuring the stability of their transmission.

[0036] In some specific implementations, such as Figure 4 As shown, both the drive wheel 4 and the detection wheel 7 are gears; the inner wall of the guide tube 1 is provided with a rack 8 that meshes with the drive wheel 4; this effectively ensures that the drive wheel 4 can rotate when the pull rod 2 moves, thereby improving the accuracy of piston rod position detection.

[0037] In some specific embodiments, four traveling wheels 9 are rotatably mounted on the pull rod 2, as shown in the figure. The pull rod 2 is arranged in a rectangular pattern. The pull rod 2 contacts the side wall of the conduit 1 through the traveling wheels 9. This effectively reduces the friction between the pull rod 2 and the conduit 1, reduces the wear of the pull rod 2 and the conduit 1, and thus improves the service life of the device.

[0038] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A piston position detection device for a hydraulic cylinder, characterized in that: Includes a conduit (1), a pull rod (2), a proximity switch (3), a drive wheel (4), an encoder (5), and a controller (6); The conduit (1) is fixedly installed on the cylinder body of the oil cylinder. A pull rod (2) is slidably installed inside the conduit (1). One end of the pull rod (2) is fixedly connected to the piston rod of the oil cylinder, and the other end is provided with a detection piece (21). A clearance hole (11) is opened on the side of the conduit (1). The detection piece (21) extends outward from the clearance hole (11). The conduit (1) is provided with a proximity switch (3) that works with the detection piece (21). There are two proximity switches (3). When the piston rod of the hydraulic cylinder is fully extended, the detection piece (21) is detected by one of the proximity switches (3); when the piston rod of the hydraulic cylinder is fully retracted, the detection piece (21) is detected by the other proximity switch (3). A drive wheel (4) is rotatably mounted on the pull rod (2), and the circumferential surface of the drive wheel (4) abuts against the inner surface of the guide tube (1); an encoder (5) is provided on the pull rod (2), and a detection wheel (7) is provided on the shaft of the encoder (5), and the outer circumferential surface of the detection wheel (7) abuts against the outer circumferential surface of the drive wheel (4) so ​​that the drive wheel (4) can drive the detection wheel (7) to rotate; The proximity switch (3), the encoder (5), and the controller (6) are connected.

2. The piston position detection device for a hydraulic cylinder according to claim 1, characterized in that: The pull rod (2) is provided with a slide groove (22), the slide groove (22) is arc-shaped, the center of the circle is on the shaft of the encoder (5), a slider (23) is slidably installed in the slide groove (22), and a spring (24) is provided between the slider (23) and one end of the slide groove (22); The drive wheel (4) is rotatably mounted on the slider (23).

3. The piston position detection device for a hydraulic cylinder according to claim 1, characterized in that: Both the drive wheel (4) and the detection wheel (7) are gears; The inner wall of the conduit (1) is provided with a rack (8) that meshes with the drive wheel (4).

4. The piston position detection device for a hydraulic cylinder according to claim 1, characterized in that: The pull rod (2) has a mounting hole (25), and the drive wheel (4) and the detection wheel (7) are installed in the mounting hole (25).

5. The piston position detection device for a hydraulic cylinder according to claim 1, characterized in that: A traveling wheel (9) is rotatably mounted on the pull rod (2), and the pull rod (2) contacts the side wall of the conduit (1) through the traveling wheel (9).

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