Torsion measuring device

Abstract

The utility model relates to a torsion measuring device which comprises a wrench body and a measuring module used for measuring torsion applied to the wrench body. The torque wrench is characterized in that the measuring module is a piezoelectric resonant sensor, the piezoelectric resonant sensor is embedded in the wrench body, and the piezoelectric resonant sensor is configured to be capable of reflecting the change of torque according to the change of oscillation frequency generated by the piezoelectric resonant sensor. The device has the advantages that the piezoelectric resonant sensor serves as a measuring module, a frequency signal generated by the piezoelectric resonant sensor due to the piezoelectric or inverse piezoelectric effect can be directly used as a force sensing signal, the principle is that the oscillation frequency of the piezoelectric resonant sensor changes under the action of external force, and the frequency variation is used as a change value for judging the force of the piezoelectric resonant sensor; a frequency value can be directly detected or converted into a voltage signal, and the piezoelectric resonant sensor has the sensor characteristics of good measurement precision, sensitivity, response time, hysteresis and the like, so that the measurement precision of torsion is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of torque measurement, in particular to a torque measurement device. Background Art

[0002] In mechanical assembly work, many parts are connected and fixed by bolts. To ensure reliable connection and fixation, a certain prestress needs to be applied to the bolts during connection and fixation. The prestress needs to be applied according to a certain loading curve, and if the torque is too large, the bolts are extremely likely to break.

[0003] To solve the above technical problems, it is necessary to detect the torque to facilitate the user to apply torque. For example, a Chinese invention patent with the application number CN202310885617.5 (publication number CN117021013A) discloses a torque wrench capable of synchronously detecting torque values. The torque wrench includes a wrench body, an extension rod, and a strain gauge, a positioning frame, a battery pack, a control module, and a display screen arranged in the extension rod. The extension rod is coaxially fixed to the wrench body and together with the wrench body forms the main structure of the torque wrench. The positioning frame is fixed inside the extension rod, the strain gauge is pasted on the positioning frame and can synchronously sense the stress change of the positioning frame. The battery pack and the control module are coaxially installed inside the positioning frame and are limited by the positioning frame. The display screen is fixed at the end of the extension rod. The battery pack is used to supply power to electrical equipment, and the control module is used to collect and analyze the data of the stress gauge and display it through the display screen.

[0004] Although the above torque wrench can realize the real-time display of torque values on the premise of retaining the original function of the wrench, so as to facilitate the operator to control and adjust the torque size and application speed in real time, and can effectively ensure the assembly quality. However, the strain gauge sensors in the prior art still have deficiencies in function parameters such as accuracy, sensitivity, and response time. Therefore, it is necessary to further improve the prior art. Summary of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide a torque measurement device that can improve the measurement accuracy in view of the above prior art.

[0006] The technical solution adopted by the utility model to solve the above technical problems is: a torque measurement device, including a wrench body and a measurement module for measuring the torque applied to the wrench body; characterized in that: the measurement module is a piezoelectric resonant sensor, the piezoelectric resonant sensor is embedded in the wrench body, and the piezoelectric resonant sensor is configured to: be able to reflect the change of torque according to the change of the oscillation frequency generated by it.

[0007] To achieve the measurement of torque, preferably, the wrench body is arranged in a first measurement state where it can rotate ±θ° around its own axis or a second measurement state where the wrench body and the force application fulcrum form a relative deflection of ±α° with respect to its central axis. By obtaining the change in the oscillation frequency generated by the piezoelectric resonant sensor in the first measurement state or the second measurement state as the detection value of the applied force and torque, the relationship between the change in oscillation frequency and torque can be obtained.

[0008] Preferably, a joint is provided at the front end of the wrench body. The wrench body is connected to the joint through an adapter, and the force application fulcrum is provided at the center of the joint.

[0009] To install the piezoelectric resonant sensor as described above, a recessed portion for embedding the piezoelectric resonant sensor is formed by inward depression on the outer wall surface of the wrench body.

[0010] The piezoelectric resonant sensor in the recessed portion is fixedly connected to the wrench body.

[0011] To achieve the display of torque for easy reading by the user, a controller and a display module are provided on the wrench body. The controller is electrically connected to the piezoelectric resonant sensor and the display module respectively.

[0012] To improve the accuracy of torque measurement, at least two piezoelectric resonant sensors are provided and are respectively arranged on two opposite side walls of the wrench body.

[0013] Preferably, the piezoelectric resonant sensor includes an outer frame and a crystal provided inside the outer frame. The crystal has piezoelectric or inverse piezoelectric effect, and a driving electrode for forming an oscillation region inside the crystal is provided inside the crystal.

[0014] Preferably, the crystal is square or circular, and at least a part of the outer wall of the crystal can abut against the inner wall of the outer frame.

[0015] Compared with the prior art, the advantages of the present utility model are as follows: By using the piezoelectric resonant sensor as the measurement module and utilizing the frequency signal generated by its piezoelectric or inverse piezoelectric effect, it can be directly used as a force sensing signal. The principle is that when an external force acts, the oscillation frequency of the piezoelectric resonant sensor changes, and the change in its frequency is used as the value for judging the change in force. It can directly detect the frequency value or convert it into a voltage signal. The piezoelectric resonant sensor has good sensor characteristics such as measurement accuracy, sensitivity, response time, and hysteresis, so the measurement accuracy of torque is improved. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the torque measurement device in the embodiment of the present utility model;

[0017] Figure 2For Figure 1 Schematic diagram of the wrench body in the second measurement state in

[0018] Figure 3 For Figure 1 Schematic diagram of the wrench body in the first measurement state in

[0019] Figure 4 For Figure 1 Schematic diagram of the first piezoelectric resonant sensor in

[0020] Figure 5 For Figure 1 Schematic diagram of the second piezoelectric resonant sensor in

[0021] Figure 6 Graph showing the relationship between the frequency change value of the piezoelectric resonant sensor and the applied torque in the embodiments of the present utility model. Detailed implementation manners

[0022] The present utility model will be further described in detail below in conjunction with the embodiments with reference to the accompanying drawings.

[0023] As Figures 1 to 5 shown, the torque measuring device in this embodiment includes a wrench body 101 and a measuring module for measuring the torque applied to the wrench body 101. In this embodiment, the measuring module is at least one piezoelectric resonant sensor.

[0024] In addition, a joint 104 is provided at the front end of the wrench body 101. The wrench body 101 is connected to the joint 104 through an adapter 103, and a force application fulcrum 105 is provided at the center of the joint 104; a controller and a display module 106 are provided on the wrench body 101, and the controller is electrically connected to the piezoelectric resonant sensor and the display module 106 respectively.

[0025] The piezoelectric resonant sensor in this embodiment is embedded in the wrench body 101, and the piezoelectric resonant sensor is configured to: be able to respond to the change in torque according to the change in the oscillation frequency it generates. In addition, in order to implement the installation of the above piezoelectric resonant sensor, a recessed portion for embedding the piezoelectric resonant sensor is formed by inward depression on the outer wall surface of the wrench body 101.

[0026] As Figure 1As shown in the figure, there are two piezoelectric resonant sensors in this embodiment, namely the first piezoelectric resonant sensor 102a and the second piezoelectric resonant sensor 102b. Correspondingly, there are two such recesses, namely the first recess 107a and the second recess 107b provided on two opposite side walls of the wrench body 101. The above-mentioned first piezoelectric resonant sensor 102a is placed in the first recess 107a, and the above-mentioned second piezoelectric resonant sensor 102b is placed in the second recess 107b. Moreover, the first piezoelectric resonant sensor 102a in the first recess 107a and the second piezoelectric resonant sensor 102b in the second recess 107b are both fixedly connected to the wrench body 101. The way of this fixed connection can be by gluing, welding, screwing or riveting. The installation positions of the above-mentioned first recess 107a and the second recess 107b are within the range of stress concentration points after the wrench body 101 is applied with force.

[0027] The wrench body 101 is arranged to be in a first measurement state where it can rotate ±θ° around its own axis or in a second measurement state where the wrench body 101 and the force application fulcrum 105 can deflect ±α° relative to their central axes. The relationship between the change in the oscillation frequency generated by the piezoelectric resonant sensor and the torque is obtained through the first measurement state or the second measurement state. Figure 1 In this, X is the distance between the central positions of the first piezoelectric resonant sensor 102a and the second piezoelectric resonant sensor 102b and the force application fulcrum 105. The way of detecting the force / torque range can be achieved by adjusting the distance of X; where X is adjusted to X1 in the first measurement state and X is adjusted to X2 in the second measurement state. When the wrench body 101 is in the first measurement state or the second measurement state, the force can be transmitted backward from the force application fulcrum 105 along the axis Z direction of the wrench body 101 to the stress concentration point range. Through the bonding material between the piezoelectric resonant sensor and the recess, such as a colloid or a metal material, the force can be transmitted to the piezoelectric resonant sensor.

[0028] In addition, as Figure 4 and Figure 5 shown, the piezoelectric resonant sensor in this embodiment includes an outer frame 401 and a crystal provided in the outer frame 401. The crystal has piezoelectric or inverse piezoelectric effects, and its material is quartz, ceramic, PZT, etc. A driving electrode for forming an oscillation region in the crystal is provided inside the crystal. And the crystal is square or circular, and at least a part of the outer wall of the crystal can abut against the inner wall of the outer frame 401. The outer frame 401 in this embodiment is formed of a high-rigidity material, such as metal and industrial plastic, etc., and can transmit the force energy completely to the crystal. The crystal can be made into different shapes, which is determined according to the requirements of force energy transmission and vibration frequency; and the thickness range of the crystal is between 5um - 300um. The range of the applied force and torque can be increased by strengthening the rigidity value of the outer frame 401.

[0029] As Figure 4 shown, the crystal in the first piezoelectric resonant sensor 102a is denoted as the first crystal 402a, and the drive electrode in the first crystal 402a is denoted as the first drive electrode 403a; the first crystal 402a is square, as Figure 5 shown, the crystal in the second piezoelectric resonant sensor 102b is denoted as the second crystal 402b, and the drive electrode in the second crystal 402b is denoted as the second drive electrode 403b; the second crystal 402b is circular. The above-mentioned first drive electrode 403a and second drive electrode 403b are used for starting and exciting the crystal, and are also the main oscillation area range. Electrodes can use low-resistance materials such as gold and silver to reduce the generation of electronic noise.

[0030] The measurement method using the above torque measurement device in this embodiment includes the following steps:

[0031] Step 1: Obtain the oscillation frequency F of the piezoelectric resonant sensor when not stressed and the oscillation frequency F1 of the piezoelectric resonant sensor when stressed;

[0032] Specifically: After the piezoelectric resonant sensor is stressed, the outer frame of the piezoelectric resonant sensor deforms, and the strain is transmitted to the crystal, thereby changing the oscillation frequency of the crystal;

[0033] Step 2: Calculate the frequency change amount △F generated by the crystal, △F = F - F1; and perform frequency doubling or frequency division processing on the frequency change amount △F to obtain the processed frequency change amount;

[0034] Step 3: Perform calculations on the processed frequency change amount in Step 2 to obtain the torque value;

[0035] In this embodiment, as Figure 6 shown, using the method of adding weights for loading, applying force to the torque measurement device, the measured frequency (Hz) change value (in the form of a quartz square crystal AT cut) and the applied torque (Nm) show a linear relationship. The frequency change amount and the torque are linearly related, and the linearity is 99%; therefore, the torque value can be calculated by substituting the frequency change amount into the relationship formula;

[0036] Step 4: Display the torque value through the display module.

[0037] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and retouches can still be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A torque measuring device, comprising a wrench body (101) and a measuring module for measuring the torque applied to the wrench body (101); characterized in that: The measuring module is a piezoelectric resonant sensor (102a, 102b), the piezoelectric resonant sensor (102a, 102b) is embedded in the wrench body (101), and the piezoelectric resonant sensor (102a, 102b) is configured to: react to a change in torque according to a change in the oscillation frequency generated by the piezoelectric resonant sensor; The wrench body (101) is arranged to be in a first measurement state in which it can rotate ±θ° around its own axis or in a second measurement state in which it can deflect ±α° relative to its central axis between the wrench body (101) and the force application fulcrum (105). The oscillation frequency variation generated by the piezoelectric resonant sensor (102a, 102b) is obtained in the first measurement state or the second measurement state as a detection value of the applied force and the torque, thereby obtaining the relationship between the oscillation frequency variation and the torque.

2. The torque measuring device according to claim 1, characterized in that: A joint (104) is provided at the front end of the wrench body (101), the wrench body (101) is connected to the joint (104) via a transition body (103), and the force application fulcrum (105) is arranged at the center of the joint (104).

3. The torque measuring device according to claim 1, characterized in that: The outer wall surface of the wrench body (101) is inwardly recessed to form a recessed portion (107a, 107b) for embedding the piezoelectric resonant sensor (102a, 102b).

4. The torque measuring device according to claim 3, characterized in that: The piezoelectric resonant sensors (102a, 102b) in the recessed portions (107a, 107b) are fixedly connected to the wrench body (101).

5. The torque measuring device according to any one of claims 1 to 4, characterized in that: The wrench body (101) is provided with a controller and a display module (106), and the controller is electrically connected to the piezoelectric resonant sensors (102a, 102b) and the display module (106) respectively.

6. The torque measuring device according to claim 5, characterized in that: There are at least two piezoelectric resonant sensors (102a, 102b), which are respectively arranged on two opposite side walls of the wrench body (101).

7. The torque measuring device according to claim 6, characterized in that: The piezoelectric resonant sensor (102a, 102b) comprises an outer frame (401) and a crystal (402a, 402b) arranged in the outer frame (401); the crystal (402a, 402b) has a piezoelectric or inverse piezoelectric effect; and a driving electrode (403a, 403b) is arranged inside the crystal (402a, 402b) for forming an oscillation region in the crystal (402a, 402b).

8. The torque measuring device according to claim 7, characterized in that: The crystals (402a, 402b) are square or circular, and at least a portion of the outer wall of the crystals (402a, 402b) can abut against the inner wall of the outer frame (401).

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