Linear displacement sensor

Abstract

The invention discloses a linear displacement sensor, which comprises a housing, and is characterized in that the housing comprises a housing body with an opening and a carbon film plate which covers the opening in a sealing manner; the pull rod is mounted in the shell and is in sliding connection with the shell, and one end of the pull rod penetrates through the shell and extends out of the shell; an electric brush is fixed to the top of the sliding core, the electric brush is connected with a second wire, and the electric brush abuts against the carbon film plate in a pressing mode; the pull rod penetrates through the sliding core and is fixed with the sliding core; the spring is installed in the shell in the length direction of the pull rod, one end of the spring abuts against the inner wall of the shell, and the other end of the spring abuts against the sliding core; the spring is installed in the shell, after external equipment presses against the pull rod, the sliding core fixed to the pull rod compresses the spring, the pull rod can be reset through the spring, the pull rod only needs to abut against the external equipment, displacement measurement can be achieved, and the pull rod does not need to be fixedly connected with the external equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of displacement detection, and in particular relates to a linear displacement sensor. Background Art

[0002] The function of a linear displacement sensor is to convert a linear mechanical displacement into an electrical signal. To achieve this effect, the traditional linear displacement sensor places a variable resistor slide rail at a fixed position of the sensor, and measures different resistance values ​​by the displacement of the slider on the slide rail. This sensor slide rail is connected to a steady-state DC voltage, allowing a small current of microamperes to flow through. The voltage between the slider and the starting end is proportional to the length of the slider movement. The carbon film linear displacement sensor uses a carbon film to evenly distribute resistance in the straight direction, applies voltage at both ends, and the brush slides on the linear carbon film to output voltage, thereby obtaining the corresponding position. If the voltage signal is converted through V / A, the current signal can also be obtained.

[0003] The Chinese invention patent with publication number CN111735374A discloses a synchronous linkage carbon film linear displacement sensor with waterproof performance. It belongs to the technical field of carbon film linear displacement sensors. It mainly solves the problem that the existing carbon film linear displacement sensor is not suitable for special and harsh environments because it does not have a waterproof protection level. Its main features include a housing, a back cover, a front cover, a circuit board assembly, an output line assembly, a strong magnet slider A assembly and a strong magnet slider B assembly; the strong magnet slider B assembly is installed in the housing; the strong magnet slider A assembly is installed outside the housing through a sliding connection mechanism; and sealing plugs are provided between the two ends of the housing and the back cover and the front cover.

[0004] This carbon film linear displacement sensor does not have an automatic reset function. Summary of the invention

[0005] The object of the present invention is to provide a linear displacement sensor to solve at least one of the above technical problems.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A linear displacement sensor, comprising:

[0008] The shell comprises a shell with an opening and a sealing cover; a carbon film plate is arranged at the opening, and one end of the carbon film plate is connected to a first wire; the shell is arranged to form an installation space, the shell opening is arranged, and the carbon film plate is used as a part of the shell, which can save the material of the shell and reduce the cost;

[0009] A pull rod installed in the housing and slidably connected to the housing, one end of which passes through the housing and extends outside the housing; the pull rod can utilize external displacement changes to drive the brush to move against the carbon film plate;

[0010] A sliding core, a brush is fixed on the top of which, the brush is connected to a second wire, and the brush is pressed against the carbon film plate; the pull rod passes through the sliding core and is fixed to the sliding core; the sliding core is used to fix the brush to the pull rod, and the shape of the sliding core can also match the installation space inside the shell to improve the stability of the brush movement; the first wire and the second wire are matched, and when the brush is pressed against the carbon film plate and moves, the resistance between the first wire and the second wire changes linearly, and this characteristic is used to convert the change in resistance into the change in displacement to measure the displacement;

[0011] A spring is installed in the housing along the length direction of the pull rod, one end of the spring abuts against the inner wall of the housing, and the other end of the spring abuts against the sliding core.

[0012] The present invention installs a spring in the shell. After the external device presses against the pull rod, the sliding core fixed to the pull rod also compresses the spring. The pull rod can be reset by the spring. The pull rod only needs to abut against the external device to achieve displacement measurement without fixedly connecting the pull rod to the external device.

[0013] Furthermore, both ends of the pull rod are penetrated by the shell, and the spring is sleeved on the pull rod, which can improve the stability of the pull rod movement. At the same time, the pull rod can also limit the spring to avoid the spring position deviation.

[0014] As another preferred scheme of the present invention, one end of the pull rod located in the shell is recessed inward to form a mounting blind hole, a limit rod is slidably installed in the mounting blind hole, and one end of the limit rod located outside the mounting blind hole is fixed to the inner wall of the shell; the spring is sleeved on the limit rod, and the limit rod is used to limit the pull rod, which is beneficial to improve the stability of the pull rod movement and can also limit the spring; the limit rod can extend into the inside of the pull rod, which is beneficial to the miniaturization of the device.

[0015] Furthermore, the limit rod is tubular, and a second air hole connected to the interior of the shell is opened on the outer wall of one end of the limit rod fixed to the shell. The second air hole is conducive to the balance of air pressure inside and outside the pull rod and the limit rod, and facilitates the sliding connection between the pull rod and the limit rod.

[0016] Preferably, a waterproof cover is provided at one end of the pull rod outside the shell, one end of the waterproof cover is sealed and fixed to the end of the pull rod, and the other end is sealed and fixed to the shell; due to the sliding connection between the pull rod and the shell, the sealing property of the connection between the pull rod and the shell is poor, and the connection between the pull rod and the shell is sealed by providing the waterproof cover, which can improve the waterproof and dustproof performance of the device; the waterproof cover is made of flexible material, and when the pull rod slides, the waterproof cover can be stretched out or stacked up, which not only plays a waterproof role but also has little resistance to the pull rod; preferably, the flexible material made of the waterproof cover can be rubber.

[0017] Furthermore, a sealing groove surrounding the pull rod is formed on the outer wall of the shell, and a sealing ring is threadedly connected to the inner surface of the sealing groove. The sealing ring presses the end of the waterproof sleeve against the bottom of the sealing groove. The waterproof sleeve is sealed to the shell through the cooperation of the sealing groove and the sealing ring, which facilitates the installation of the waterproof sleeve and is also conducive to the disassembly and replacement of the waterproof sleeve after aging.

[0018] Furthermore, an annular sealing gasket is provided between the waterproof sleeve and the sealing ring and between the waterproof sleeve and the sealing groove. The annular sealing gasket is conducive to better sealing and fixing between the waterproof sleeve and the sealing ring, and can also protect the waterproof sleeve to avoid damage during installation.

[0019] Furthermore, a first thread is provided on the side wall of the sealing groove away from the pull rod, and a second thread matching the first thread is provided on the outer peripheral wall of the sealing ring. The threaded connection between the sealing groove and the sealing ring is realized by the first thread and the second thread. A certain space can be left on the inner side of the sealing ring to avoid squeezing the waterproof cover and causing damage to the waterproof cover.

[0020] Furthermore, a sealing ring is provided at one end of the waterproof cover away from the shell, and the sealing ring presses the waterproof cover against the pull rod. The waterproof cover and the end of the pull rod are sealed and fixed by the provided sealing ring, which facilitates the installation and removal of the waterproof cover.

[0021] Furthermore, a first air hole connected to the bottom of the installation blind hole is opened on the outer wall of the pull rod, and the first air hole is located in the waterproof cover; the opening of the first air hole is beneficial to the balance of air pressure inside and outside the pull rod, and facilitates the sliding connection between the pull rod and the limit rod; through the cooperation of the first air hole and the second air hole, the internal space of the waterproof cover, the installation blind hole, the internal space of the limit rod and the internal space of the outer shell can be connected, which is convenient for achieving air pressure balance and helps to reduce the resistance when the pull rod moves.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention installs a spring in the housing. When the external device presses against the pull rod, the sliding core fixed to the pull rod also compresses the spring. The pull rod can be reset by the spring. The pull rod only needs to abut against the external device to achieve displacement measurement without the need to fix the pull rod to the external device.

[0024] (2) The limiting rod provided in the present invention is used to limit the position of the pull rod, which is beneficial to improving the stability of the pull rod movement and can also limit the spring; the limiting rod can extend into the inside of the pull rod, which is also beneficial to the miniaturization of the device;

[0025] (3) The waterproof cover of the present invention seals the connection between the pull rod and the shell, thereby improving the waterproof and dustproof performance of the device; the waterproof cover is made of flexible material, and when the pull rod slides, the waterproof cover can be stretched out or stacked up, which not only plays a waterproof role but also has little resistance to the pull rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 An exploded diagram of a linear displacement sensor in Example 1;

[0027] Figure 2 A cross-sectional view of a linear displacement sensor in Example 2;

[0028] Figure 3 for Figure 2 A partial enlarged view of the middle part;

[0029] In the figure: 1. outer shell; 101. shell; 102. carbon film plate; 2. pull rod; 3. sliding core; 4. brush; 5. spring; 6. mounting blind hole; 7. limit rod; 8. sealing ring; 9. e-type retaining ring; 10. waterproof cover; 11. sealing groove; 12. sealing ring; 13. sealing gasket. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figure 1 As shown, this embodiment provides a linear displacement sensor, including a housing 1, a pull rod 2, a sliding core 3 and a spring 5.

[0033] The shell 1 includes a shell 101 with an opening and a carbon film plate 102 with a sealing cover arranged at the opening, and one end of the carbon film plate 102 is connected to a first wire; the shell 1 is set to form an installation space, the shell 101 is set with an opening, and the carbon film plate 102 is used as a part of the shell 1, which can save materials for the shell 101 and reduce costs.

[0034] The pull rod 2 is installed in the housing 101 and is slidably connected to the housing 101. One end of the pull rod 2 passes through the housing 101 and extends outside the housing 101. The set pull rod 2 can utilize external displacement changes to drive the brush 4 to move along the carbon film plate 102.

[0035] A brush 4 is fixed on the top of the sliding core 3, and the brush 4 is connected to a second wire. The brush 4 is pressed against the carbon film plate 102; the pull rod 2 passes through the sliding core 3 and is fixed to the sliding core 3; the sliding core 3 is used to fix the brush 4 to the pull rod 2, and the shape of the sliding core 3 can also cooperate with the installation space inside the shell 1 to improve the stability of the movement of the brush 4; by cooperating with the first wire and the second wire, when the brush 4 is pressed against the carbon film plate 102 and moves, the resistance between the first wire and the second wire changes linearly, and this characteristic is used to convert the change in resistance into the change in displacement to measure the displacement.

[0036] The spring 5 is installed in the shell 101 along the length direction of the pull rod 2, one end of the spring 5 abuts against the inner wall of the shell 101, and the other end abuts against the sliding core 3; preferably, both ends of the pull rod 2 are penetrated by the shell 101, and the spring 5 is sleeved on the pull rod 2, which can improve the stability of the movement of the pull rod 2. At the same time, the pull rod 2 can also limit the spring 5 to avoid the position displacement of the spring 5; preferably, one end of the sliding core 3 is abutted by the spring 5, and the other end can block the sliding core 3 by the e-type retaining ring 9 clamped on the pull rod 2, thereby fixing the sliding core 3 on the pull rod 2.

[0037] The present invention installs a spring 5 in the housing 101. After the external device presses against the pull rod 2, the sliding core 3 fixed to the pull rod 2 also compresses the spring 5. The spring 5 can be used to reset the pull rod 2. The pull rod 2 can achieve displacement measurement only by abutting against the external device without fixing the pull rod 2 to the external device.

[0038] Example 2

[0039] like Figure 2As shown, the difference between this embodiment and embodiment 1 is that only one end of the pull rod 2 passes through the shell 101, and the end of the pull rod 2 located in the shell 101 is recessed inward to form a mounting blind hole 6, and a limiting rod 7 is slidably installed in the mounting blind hole 6, and the end of the limiting rod 7 located outside the mounting blind hole 6 is fixed to the inner wall of the shell 101; the spring 5 is sleeved on the limiting rod 7, and the limiting rod 7 is used to limit the pull rod 2, which is beneficial to improve the stability of the movement of the pull rod 2, and can also limit the spring 5; the limiting rod 7 can extend into the inside of the pull rod 2, which is beneficial to the miniaturization of the device.

[0040] Furthermore, the limiting rod 7 is tubular, and a second air hole connected to the interior of the shell 101 is opened on the outer wall of the end of the limiting rod 7 fixed to the shell 101. The second air hole is conducive to the balance of air pressure inside and outside the pull rod 2 and the limiting rod 7, and facilitates the sliding connection between the pull rod 2 and the limiting rod 7.

[0041] Furthermore, a waterproof cover 10 is provided at one end of the pull rod 2 outside the shell 101, one end of the waterproof cover 10 is sealed and fixed to the end of the pull rod 2, and the other end is sealed and fixed to the shell 101; due to the sliding connection between the pull rod 2 and the shell 101, the sealing performance of the connection between the pull rod 2 and the shell 101 is poor, and the connection between the pull rod 2 and the shell 101 is sealed by setting the waterproof cover 10, which can improve the waterproof and dustproof performance of the device; the waterproof cover 10 is made of a flexible material, and when the pull rod 2 slides, the waterproof cover 10 can be stretched or stacked up, which not only plays a waterproof role, but also has little resistance to the pull rod 2; preferably, the flexible material made of the waterproof cover 10 can be rubber.

[0042] Furthermore, if Figure 3 As shown, a sealing groove 11 surrounding the pull rod 2 is opened on the outer wall of the shell 101, and a sealing ring 12 is connected to the inner thread of the sealing groove 11. The sealing ring 12 presses the end of the waterproof cover 10 against the bottom of the sealing groove 11. The sealing groove 11 is provided to cooperate with the sealing ring 12 to seal the waterproof cover 10 and the shell 101, which is convenient for the installation of the waterproof cover 10 and also conducive to the disassembly and replacement of the waterproof cover 10 after aging.

[0043] Furthermore, an annular sealing gasket 13 is provided between the waterproof cover 10 and the sealing ring 12, and between the waterproof cover 10 and the sealing groove 11. The annular sealing gasket 13 is provided to facilitate better sealing and fixing between the waterproof cover 10 and the sealing ring 12, and can also protect the waterproof cover 10 to avoid damage during installation.

[0044] Furthermore, a first thread is provided on the side wall of the sealing groove 11 away from the pull rod 2, and a second thread matching the first thread is provided on the outer peripheral wall of the sealing ring 12. The threaded connection between the sealing groove 11 and the sealing ring 12 is realized by the first thread and the second thread. A certain space can be left on the inner side of the sealing ring 12 to avoid squeezing the waterproof cover 10 and causing damage to the waterproof cover 10.

[0045] Furthermore, a sealing ring 8 is provided at one end of the waterproof cover 10 away from the housing 101, and the sealing ring 8 presses the waterproof cover 10 against the pull rod 2. The sealing ring 8 is provided to achieve sealing and fixation between the waterproof cover 10 and the end of the pull rod 2, which facilitates the installation and removal of the waterproof cover 10.

[0046] Example 3

[0047] The difference between this embodiment and embodiment 2 is that a first air hole connected to the bottom of the installation blind hole 6 is opened on the outer wall of the pull rod 2, and the first air hole is located in the waterproof sleeve 10; the opening of the first air hole is beneficial to the balance of air pressure inside and outside the pull rod 2, and facilitates the sliding connection between the pull rod 2 and the limit rod 7; through the cooperation of the set first air hole and the second air hole, the internal space of the waterproof sleeve 10, the installation blind hole 6, the internal space of the limit rod 7 and the internal space of the outer shell 1 can be connected, which is convenient for achieving air pressure balance and helps to reduce the resistance of the pull rod 2 during movement.

[0048] It should be noted that although the present invention is disclosed as above by specific embodiments, the above embodiments are not intended to limit the present invention. Ordinary technicians in this field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A linear displacement sensor, characterized in that: include: A housing, the housing comprising a shell having an opening and a sealing cover; a carbon film plate provided at the opening, one end of the carbon film plate being connected to a first wire; A pull rod installed in the shell and slidably connected to the shell, one end of which passes through the shell and extends outside the shell; A sliding core, a brush is fixed on the top of which, the brush is connected to a second wire, and the brush is pressed against the carbon film plate; the pull rod passes through the sliding core and is fixed to the sliding core; A spring is installed in the housing along the length direction of the pull rod, one end of the spring abuts against the inner wall of the housing, and the other end of the spring abuts against the sliding core.

2. The linear displacement sensor according to claim 1, characterized in that: Both ends of the pull rod are penetrated by the housing, and the spring is sleeved on the pull rod.

3. The linear displacement sensor according to claim 1, characterized in that: One end of the pull rod located in the shell is recessed inward to form a mounting blind hole, a limit rod is slidably installed in the mounting blind hole, and one end of the limit rod located outside the mounting blind hole is fixed to the inner wall of the shell; the spring is sleeved on the limit rod.

4. The linear displacement sensor according to claim 3, characterized in that: The limiting rod is tubular, and a second air hole communicating with the interior of the limiting rod is formed on the outer wall of one end of the limiting rod fixed to the shell.

5. The linear displacement sensor according to claim 4, characterized in that: One end of the pull rod outside the shell is sleeved with a waterproof sleeve, one end of the waterproof sleeve is sealed and fixed to the end of the pull rod, and the other end of the waterproof sleeve is sealed and fixed to the shell.

6. The linear displacement sensor according to claim 5, characterized in that: The outer wall of the shell is provided with a sealing groove surrounding the pull rod, and a sealing ring is threadedly connected to the inner surface of the sealing groove. The sealing ring presses the end of the waterproof sleeve against the bottom of the sealing groove.

7. The linear displacement sensor according to claim 6, characterized in that: An annular sealing gasket is provided between the waterproof sleeve and the sealing ring and between the waterproof sleeve and the sealing groove.

8. The linear displacement sensor according to claim 6, characterized in that: A first thread is arranged on a side wall of the sealing groove away from the pull rod, and a second thread matching with the first thread is arranged on an outer peripheral wall of the sealing ring.

9. The linear displacement sensor according to claim 5, characterized in that: A sealing ring is sleeved on one end of the waterproof sleeve away from the housing, and the sealing ring presses the waterproof sleeve against the pull rod.

10. The linear displacement sensor according to claim 5, characterized in that: The outer wall of the pull rod is provided with a first air hole which is in communication with the bottom of the installation blind hole, and the first air hole is located in the waterproof sleeve.

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