A displacement measuring device

Abstract

The present invention relates to the field of sensor technology, and in particular to a displacement measuring device, comprising a pressure sensor and a push-pull member, wherein the pressure sensor is configured to be fixedly installed, the push-pull member is configured to be slidably installed, the push-pull member is configured with an elastic member, and when the push-pull member moves, the elastic member acts on the pressure sensor, the pressure sensor transmits a pressure signal to a controller, and the controller converts the pressure change into a displacement. The displacement measuring device provided by the present invention improves the minimum recognition accuracy of the measuring device, and can effectively reduce the cost and extend the service life of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a displacement measuring device. Background Art

[0002] An electronic ruler, also known as a linear displacement sensor, is a device that converts physical displacement into electrical signals for displacement measurement.

[0003] The electronic ruler in the prior art is generally a sliding resistor type or a grating type structure. Among them, the sliding resistor type uses a pull rope to drive the wheel axle, causing the potentiometer in the center of the wheel axle to produce a resistance change, and measures the potentiometer voltage to determine the distance the pull rope is pulled out. This structure is complex to install and requires a large space. The pull rope is prone to wear and breakage, and the damage rate of the potentiometer is high after long-term operation. The grating ruler is a digital relative coding reading, and a counter is used to calculate the ruler position. The ruler rod needs to drive the grating to move together. Its accuracy is determined according to the grating accuracy and the photoelectric tube accuracy. This characteristic limits the minimum recognition accuracy of the grating ruler, and it is impossible to achieve a smaller resolution to express the length expressed by the ruler. Improving the minimum recognition accuracy of the grating ruler will greatly increase the cost. Summary of the invention

[0004] The present invention solves the technical problems of low minimum recognition accuracy and high cost of electronic rulers in the prior art, and proposes a displacement measuring device. The application of the displacement measuring device improves the minimum recognition accuracy, and at the same time can extend the service life of the device and reduce costs.

[0005] The technical solution of the present invention:

[0006] A displacement measuring device, comprising:

[0007] a pressure sensor configured for fixed installation;

[0008] A push-pull member, wherein the push-pull member is configured to be slidably installed, and the push-pull member is configured with an elastic member. When the push-pull member moves, the elastic member acts on the pressure sensor, and the pressure sensor transmits a pressure signal to a controller, and the controller converts the pressure change into a displacement.

[0009] When the push-pull member moves, whether it is toward the pressure sensor or away from the pressure sensor, the elastic member will act on the pressure sensor. The pressure sensor will be subjected to pressures of different sizes applied by the elastic member, and convert the pressure it receives into an electrical signal and transmit it to the controller. The controller converts the pressure change into a displacement. In this way, the displacement measuring device of the present application converts the displacement change into a pressure change through the elastic member, and then converts the pressure change into an electrical signal through the pressure sensor. Finally, the controller converts the electrical signal into a displacement output.

[0010] Furthermore, the pressure sensor comprises:

[0011] A cantilever bracket, the cantilever bracket comprising a pressure-bearing portion, a cantilever and a support portion configured to be fixedly installed, the pressure-bearing portion is connected to the support portion through the cantilever, the push-pull member passes through the pressure-bearing portion and is a clearance fit, and the elastic member presses against the pressure-bearing portion under the action of the push-pull member;

[0012] A strain gauge is mounted on the cantilever.

[0013] Furthermore, the elastic member is a spring, the spring is sleeved on the push-pull member, one end of the spring and the push-pull member are relatively fixed, and the other end of the spring presses the pressure sensor.

[0014] Preferably, the displacement measuring device further comprises a sliding sleeve, which is fixedly mounted on the pressure-bearing portion, and the sliding sleeve transmits the force of the elastic member to the pressure-bearing portion.

[0015] Furthermore, the sliding sleeve is fixedly mounted on one side of the cantilever bracket, and a limiting member is provided on the other side of the cantilever bracket, and the limiting member is fixedly connected to the push-pull member.

[0016] Preferably, a fixing seat is provided on the push-pull member, and one end of the spring presses the fixing seat.

[0017] Furthermore, the displacement measuring device further comprises a sampling circuit board, on which the controller is provided, and the controller converts the pressure change into the displacement.

[0018] Furthermore, the sampling circuit board is also provided with an analog-to-digital conversion module and a digital interface, and the analog-to-digital conversion module converts the pressure signal into a displacement digital signal and outputs it through the digital interface; at the same time, the sampling circuit board is also provided with a digital processing module, a digital-to-analog conversion module and an analog interface, and the digital processing module processes the digital signal output by the analog-to-digital conversion module and outputs it to the digital-to-analog conversion module, and the digital-to-analog conversion module outputs a displacement analog signal and outputs it through the analog interface.

[0019] Furthermore, the displacement measurement sensor further comprises a housing, the pressure sensor is fixedly mounted in the housing, and at least one end of the push-pull member is located outside the housing.

[0020] Furthermore, at least a portion of the elastic member is located inside the shell.

[0021] After adopting the above technical solution, the displacement measuring device provided by the present invention has the following beneficial effects compared with the prior art:

[0022] (1) The displacement measuring device of the present invention is provided with an elastic member on the push-pull member. When the push-pull member moves, the elastic member acts on the pressure sensor, and the pressure sensor converts the pressure change into a displacement output. The overall structure is simple and the cost is low. At the same time, the pressure sensor makes the minimum recognition accuracy and sensitivity of the present invention higher.

[0023] (2) In the present invention, only the elastic coefficient of the spring and the parameters of the cantilever bracket need to be set to ensure that the minimum recognition accuracy of the measurement reaches 1um, while the minimum recognition accuracy of the electronic ruler in the prior art is about 25um. It can be seen that the minimum recognition accuracy of the displacement measurement device of the present invention is much higher than that of the prior art. At the same time, the price of the strain gauge is relatively low, which can effectively save costs;

[0024] (3) The present invention fixes the sliding sleeve on the pressure-bearing part by means of a fixing hole. The sliding sleeve is equivalent to a sliding bearing. In this way, the push-pull member and the sliding sleeve are slidably matched, which reduces friction, makes the movement of the push-pull rod more flexible and fast, and reduces the measurement error caused by friction.

[0025] (4) The pressure-bearing part, cantilever and supporting part of the present invention can be integrally formed, and the material is alloy steel. The alloy steel has high strength, is not prone to plastic deformation when the measurement range is met, has good stability and high reliability;

[0026] (5) The displacement measuring device of the present invention is equipped with both commonly used digital interfaces such as an HDMI interface and an analog interface such as a VGA interface, which is applicable to a wide range of scenarios and convenient for users to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of a displacement measuring device according to an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the structure of a cantilever bracket according to an embodiment of the present invention;

[0029] Figure 3 is a schematic structural diagram of a pressure sensor according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the principle of a displacement measuring device according to an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the overall structure of the displacement measuring device (with housing) according to an embodiment of the present invention.

[0032] in,

[0033] Pressure sensor 1, cantilever bracket 11, pressure bearing part 111, cantilever 112, supporting part 113, strain gauge 12;

[0034] Push-pull member 2, elastic member 21, sliding sleeve 22, limiting member 23, fixing seat 24;

[0035] Shell 3 , sampling circuit board 31 , connection port 32 . DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. 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.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0039] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0040] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0041] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0042] like Figure 1 As shown, the displacement measuring device of this embodiment includes a pressure sensor 1 and a push-pull member 2. The push-pull member 2 is provided with an elastic member 21. The elastic member 21 is preferably a spring. The spring is sleeved on the push-pull member 2. Figure 1 The left end of the middle spring and the push-pull member 2 are relatively fixed, and the right end of the spring acts on the pressure sensor 1. Furthermore, the push-pull member 2 is configured to be slidably installed. When the push-pull member 2 moves, whether it moves toward the pressure sensor 1 or away from the pressure sensor 1, the spring will act on the pressure sensor 1. The pressure sensor 1 will be subjected to different pressures applied by the spring, and the pressure will be converted into an electrical signal and transmitted to the controller. The controller converts the pressure change into a displacement. In this way, the displacement measuring device of this embodiment converts the displacement change into a pressure change through the spring, and then converts the pressure change into a changing electrical signal through the pressure sensor 1. Finally, the controller converts the changing electrical signal into a displacement output.

[0043] It should be noted that the state of the spring can be in a compressed state or in a stretched state. In order to ensure the accuracy of the measurement, the spring of this embodiment is preferably always in a compressed state, and the pressure sensor 1 is always under pressure.

[0044] A pressure sensor is a sensor that converts pressure change signals into electrical signals for output after sensing pressure changes. Pressure sensors usually use strain gauges based on strain effect or piezoelectric crystals based on piezoelectric effect to convert pressure signals and electrical signals. The minimum recognition accuracy of piezoelectric crystals or strain gauges can reach 0.1um or even less, and this is the material property of piezoelectric crystals or strain gauges, and does not need to rely on very high processing accuracy like grating rulers. In this embodiment, only the parameters of the pressure sensor need to be set to ensure that the minimum recognition accuracy of the measurement reaches 1um, while the minimum recognition accuracy of the electronic ruler in the prior art is about 25um. It can be seen that the minimum recognition accuracy of the displacement measurement device in this embodiment is much higher than that of the prior art. At the same time, the price of piezoelectric crystals or strain gauges is low, which can effectively save costs.

[0045] From the above content, it can be seen that the displacement measuring device of this embodiment is configured by arranging a spring on the push-pull member 2. When the push-pull member 2 moves, the spring acts on the pressure sensor 1, and the pressure sensor 1 converts the pressure change into a displacement output. The overall structure is simple and the cost is low. At the same time, the pressure sensor 1 makes the minimum recognition accuracy and sensitivity of this embodiment higher.

[0046] Preferably, if Figure 2 and 3 As shown, the pressure sensor 1 of this embodiment adopts a structure of a cantilever bracket 11 combined with a strain gauge 12. The cantilever bracket 11 includes a pressure-bearing portion 111, a cantilever 112 and a support portion 113 configured to be fixedly installed. The pressure-bearing portion 111 is connected to the support portion 113 through the cantilever 112. The push-pull member 2 penetrates the pressure-bearing portion 111 and is a clearance fit. The elastic member 21 presses against the pressure-bearing portion 111 under the action of the push-pull member 2; specifically, as shown in FIG. Figure 2 As shown, the support portion 113 is square and hollow in the middle, and the four corners of the support portion 113 are provided with mounting holes so that it can be mounted on a rigid object. The pressure-bearing portion 111 is annular and is located in the hollow inside of the support portion 113 and is connected to the support portion 113 through the cantilever 112.

[0047] Furthermore, in this embodiment, a strain gauge 12 is installed on the cantilever 112. After ensuring that the cantilever 112 is smooth and flat, the strain gauge 12 is bonded to the cantilever 112, and after the strain gauge 12 is tightly bonded, it is clamped by a special clamp. At the same time, silicone is evenly applied on the strain gauge 12 to prevent water and dust, thereby extending the service life of the displacement measuring device of this embodiment.

[0048] like Figure 1-2 As shown, the center hole of the annular pressure-bearing part 111 can accommodate the rod-shaped push-pull member 2 to move through, and the two are clearance-matched. When the push-pull member 2 moves, the elastic member 21 always presses against the pressure-bearing part 111. The pressure-bearing part 111 will bend to different degrees due to the different forces applied by the elastic member 21, and the cantilever 112 will deform to different degrees. The strain gauge 12 will also deform to different degrees, and its resistance will also change accordingly. The controller calculates and outputs the displacement according to the voltage value at both ends of the strain gauge 12 detected.

[0049] It should be noted that here, only the elastic coefficient of the spring and the parameters of the cantilever bracket 11 need to be set to ensure that the minimum recognition accuracy of the measurement reaches 1um. At the same time, the entire conversion process of this embodiment is a linear change, including the deformation of the spring, the deformation of the cantilever bracket 11 and the micro-deformation of the strain gauge, which is convenient for calculation and makes the output result more stable and accurate.

[0050] Preferably, the pressure-bearing portion 111, the cantilever 112 and the supporting portion 113 can be integrally formed, and the material is alloy steel. The alloy steel has high strength, is not prone to plastic deformation when the measurement range is met, has good stability and high reliability.

[0051] Preferably, if Figure 1 As shown, the displacement measuring device of this embodiment further includes a sliding sleeve 22, which is fixedly mounted on the pressure-bearing portion 111, and the sliding sleeve 22 transmits the force of the spring to the pressure-bearing portion 111, so that the pressure-bearing portion 111 is deformed. Specifically, as Figure 2 As shown, the pressure-bearing part 111 is provided with a plurality of fixing holes, by means of which the sliding sleeve 22 can be fixedly mounted on the pressure-bearing part 111. The sliding sleeve 22 is equivalent to a sliding bearing, so that the push-pull member 2 and the sliding sleeve 22 slide together, reducing friction, making the movement of the push-pull rod more flexible and fast, and reducing the measurement error caused by friction. Of course, a linear bearing can also be used to replace the sliding sleeve 22, which has less friction and better sliding effect. It should be noted that, since the middle hole of the pressure-bearing part 111 does not play a clearance fit role after the sliding sleeve 22 is used, the middle hole of the pressure-bearing part 111 can be set to be larger than the outer diameter of the sliding sleeve 22, so that the machining accuracy requirements for the hole wall of the middle hole will be reduced.

[0052] Furthermore, the sliding sleeve 22 of the present embodiment is installed on one side of the cantilever bracket 11, and the other side of the cantilever bracket 11 is also provided with a stopper 23, and the stopper 23 is fixed to the other end of the push-pull member 2, and the fixing method of the threaded connection is optional but not limited to, and, as Figure 1As shown, the limiter 23 prevents the other end of the push-pull member 2 from leaving the cantilever bracket 11 to the left. Specifically, a limiter rod can be provided on the limiter 23, or the outer dimensions of the limiter 23 can be set to be larger than the size of the middle hole of the pressure-bearing portion 111. Preferably, under the action of the spring, when the limiter 23 abuts against the cantilever bracket 11, it is the zero position of the displacement measuring device of this embodiment.

[0053] Preferably, if Figure 1 As shown, a fixing seat 24 is fixed to one end of the push-pull member 2, and the fixing method may be, but is not limited to, a threaded connection. One end of the spring presses the fixing seat 24, and the other end of the spring presses the sliding sleeve 22. Since the spring is always in a compressed state, during the movement of the push-pull member 2, one end of the spring is relatively fixed to the fixing seat 24 and will not separate. Of course, the two can also be directly fixed, and the specific fixing method may be, but is not limited to, welding.

[0054] Furthermore, if Figure 1 As shown, during use, the cantilever bracket 11 is fixed, and a moving device such as a driver of an injection molding machine drives the fixing seat 24 to move left and right to perform displacement measurement. The fixing seat 24 of this embodiment is in a truncated cone shape, wherein the bottom surface with a smaller area faces the spring side, and the bottom surface with a larger area contacts the driver, so that the fixing seat 24 and the driver are in surface contact. In this way, as long as the bottom surface of the fixing seat 24 is perpendicular to the push-pull member 2, it can be ensured that the driver always moves along the length direction of the push-pull member 2, and the measurement result is more accurate and the error is smaller.

[0055] Furthermore, if Figure 4-5 As shown, the displacement measuring device of the present embodiment further includes a housing 3 and a sampling circuit board 31 arranged inside the housing 3. The sampling circuit board 31 is provided with a controller, which converts the pressure change into a displacement. In addition, the sampling circuit board 31 is also provided with an analog-to-digital conversion module and a digital interface. The analog-to-digital conversion module converts the pressure signal into a digital signal of displacement and outputs it through the digital interface. At the same time, the sampling circuit board 31 is also provided with a digital processing module, a digital-to-analog conversion module and an analog interface. The digital processing module processes the digital signal output by the analog-to-digital conversion module and outputs it to the digital-to-analog conversion module. The digital-to-analog conversion module outputs an analog signal of displacement and outputs it through the analog interface. In this way, the displacement measuring device of the present embodiment is equipped with both commonly used digital interfaces such as an HDMI interface and analog interfaces such as a VGA interface, which is applicable to a wide range of scenarios and convenient for users to use.

[0056] like Figure 5As shown, the pressure sensor 1 of this embodiment is built into the housing 3. Specifically, four mounting holes are provided at the four corners of the supporting portion 113 of the cantilever bracket 11. The supporting portion 113 of the cantilever bracket 11 is fixedly installed in the housing 3 through the four mounting holes. One end of the push-pull member 2, namely the fixing seat 24, is located on the outside of the housing 3. In this way, the fixing seat 24 can be moved to perform displacement measurement. At the same time, a connecting port 32 is also provided on the housing 3 for electrical connection with other devices such as a display.

[0057] Optionally, a portion of the spring of this embodiment is configured on the outside of the shell 3. Of course, the entire spring can also be configured on the inside of the shell 3, but it is necessary to configure a limit seat similar to the fixed seat 24 on the push-pull member on the inside of the shell 3. When the push-pull member moves, the spring is compressed. In this way, the spring cannot be seen from the outside, the overall look is more beautiful, and it does not affect the actual measurement.

[0058] It can be seen from the above content that the displacement measuring device provided in this embodiment improves the minimum recognition accuracy of the measurement, and at the same time can effectively reduce the cost and extend the service life of the displacement measuring device.

[0059] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A displacement measuring device, characterized in that: include: A pressure sensor (1), wherein the pressure sensor (1) is configured to be fixedly installed; A push-pull member (2), the push-pull member (2) being configured to be slidably mounted, the push-pull member (2) being configured with an elastic member (21), the elastic member (21) acting on the pressure sensor (1) when the push-pull member (2) moves, the pressure sensor (1) transmitting a pressure signal to a controller, and the controller converting a pressure change into a displacement; The pressure sensor (1) comprises: a cantilever bracket (11), the cantilever bracket (11) comprising a pressure-bearing portion (111), a cantilever (112) and a support portion (113) configured to be fixedly installed, the pressure-bearing portion (111) being connected to the support portion (113) via the cantilever (112), the push-pull member (2) penetrating the pressure-bearing portion (111) and being a clearance fit, and the elastic member (21) being pressed against the pressure-bearing portion (111) under the action of the push-pull member (2); a strain gauge, the strain gauge being mounted on the cantilever (112); The displacement measuring device further comprises a sliding sleeve (22), wherein the sliding sleeve (22) is fixedly mounted on the pressure-bearing portion (111), and the sliding sleeve (22) transmits the force of the elastic member (21) to the pressure-bearing portion (111); The elastic member (21) is a spring, and the spring is sleeved on the push-pull member (2). One end of the spring is fixed to the push-pull member (2), and the other end of the spring presses the pressure sensor (1).

2. A displacement measuring device according to claim 1, characterized in that: The sliding sleeve (22) is fixedly mounted on one side of the cantilever bracket (11), and a limiting member (23) is provided on the other side of the cantilever bracket (11), wherein the limiting member (23) is fixedly connected to the push-pull member (2).

3. A displacement measuring device according to claim 1, characterized in that: A fixing seat (24) is provided on the push-pull member (2), and one end of the spring presses the fixing seat (24).

4. A displacement measuring device according to claim 1, characterized in that: The displacement measuring device further comprises a sampling circuit board (31), on which the controller is provided, and the controller converts the pressure variation into a displacement.

5. A displacement measuring device according to claim 4, characterized in that: The sampling circuit board (31) is also provided with an analog-to-digital conversion module and a digital interface. The analog-to-digital conversion module converts the pressure signal into a displacement digital signal and outputs it through the digital interface. At the same time, the sampling circuit board (31) is also provided with a digital processing module, a digital-to-analog conversion module and an analog interface. The digital processing module processes the digital signal output by the analog-to-digital conversion module and outputs it to the digital-to-analog conversion module. The digital-to-analog conversion module outputs a displacement analog signal and outputs it through the analog interface.

6. A displacement measuring device according to claim 1, characterized in that: The displacement measuring device further comprises a housing (3), the pressure sensor (1) being fixedly mounted inside the housing (3), and at least one end of the push-pull member (2) being located outside the housing (3).

7. A displacement measuring device according to claim 6, characterized in that: At least a portion of the elastic member (21) is located inside the housing (3).

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