A volumetric tube friction force measuring device and method

Abstract

The present application relates to a kind of volume tube friction measuring device and method, the friction measuring device includes volume tube, piston, inductor and controller, piston is installed in volume tube, it can move along the axial direction of volume tube;Inductor is fixedly installed on volume tube, its probe extends to volume tube, and it is connected with controller, for inducting the position of piston, and corresponding position signal is sent to controller, controller receives corresponding position signal and calculates the friction of volume tube.The beneficial effects of the present application are simple structure, reasonable design, can quickly measure the friction between piston and volume tube, convenient to measure, and high accuracy.

Description

Technical Field

[0001] This invention relates to the field of volume tube friction force measurement technology, specifically to a volume tube friction force measurement device and method. Background Technology

[0002] Measurement of piston friction force in volumetric tube standard instruments. Currently, friction force is not measured during piston assembly of volumetric tubes used for metrology. Piston replacement and maintenance are mostly based on experience, and there is no reliable testing device or method for the dynamic seal between the volumetric tube and the piston. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a volume tube friction force measuring device and method, which aims to solve the problems in the prior art.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0005] A volume tube friction force measuring device includes a volume tube, a piston, a sensor, and a controller. The piston is installed inside the volume tube and can move along the axial direction of the volume tube. The sensor is fixedly installed on the volume tube, with its probe extending into the volume tube and communicatively connected to the controller. The sensor senses the position of the piston and sends the corresponding position signal to the controller. The controller receives the corresponding position signal and calculates the friction force of the volume tube.

[0006] The beneficial effects of the present invention are as follows: During measurement, firstly, the two positions of the piston inside the volume tube are detected by the sensor, and the corresponding position signals are sent to the controller; then, the controller receives the corresponding position signals and calculates the friction force of the volume tube.

[0007] This invention has a simple structure and reasonable design, and can quickly measure the frictional force between the piston and the volume tube. The measurement is convenient and highly accurate.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, it also includes a drive assembly, which is connected to the piston via a transmission component to drive the piston to move.

[0010] The advantage of adopting the above-mentioned further solution is that during measurement, the piston is driven to move inside the volume tube by the drive component, so as to realize the automatic movement of the piston, which facilitates the measurement of the friction force of the volume tube.

[0011] Furthermore, the transmission component is a connecting rod, and the two ends of the connecting rod are fixedly connected to the piston and the drive assembly, respectively.

[0012] The advantages of adopting the above-mentioned further solution are that it has a simple structure, reasonable design, and convenient connection between the piston and the drive assembly through the connecting rod.

[0013] Furthermore, the drive assembly includes a slide table and a servo motor. The slide table is fixedly mounted on one end of the volume tube. The servo motor is fixedly mounted on the slide table, with its drive end extending along the axial direction of the volume tube and connected to the transmission component via a transmission device, and communicating with the controller.

[0014] The advantage of adopting the above-mentioned further solution is that during measurement, the servo motor rotates and drives the transmission component and the horizontal end of the piston through the transmission device, thereby realizing the automatic movement of the piston so as to measure the friction force of the volume tube, which is convenient.

[0015] Furthermore, the transmission device is a lead screw transmission device, which is mounted on the slide table, and the nut on it is fixedly connected to the transmission component.

[0016] The advantages of adopting the above-mentioned further scheme are that it has a simple structure, reasonable design, and uses a screw drive to convert its own rotation into linear movement of the nut, transmission components and piston, which is convenient for transmission.

[0017] Furthermore, the transmission device is a synchronous belt transmission device, which is mounted on the slide table, and the slider on it is fixedly connected to the transmission component.

[0018] The advantages of adopting the above-mentioned further scheme are that it has a simple structure, reasonable design, and uses a synchronous belt drive to convert the rotation of its own synchronous belt into the linear movement of the slider, transmission components and piston on it, which is convenient for transmission.

[0019] Furthermore, the sensor includes multiple electronic switches, which are fixedly mounted on the volume tube at uniform intervals along the axial direction of the volume tube, extending into the volume tube and communicating with the controller.

[0020] The advantage of adopting the above-mentioned further solution is that during measurement, the piston's position is detected by multiple electronic switches during its movement, and the corresponding position signals are sent to the controller, making detection convenient.

[0021] Furthermore, the sensor includes multiple position sensors, which are fixedly mounted on the volume tube at uniform intervals along the axial direction of the volume tube, extending into the volume tube and communicating with the controller.

[0022] The advantage of adopting the above-mentioned further solution is that during measurement, the piston's position is detected by multiple position sensors during its movement, and the corresponding position signals are sent to the controller, making detection convenient.

[0023] Furthermore, the piston has a cylindrical structure, and its edges slide against the inner wall of the volume tube.

[0024] The advantage of adopting the above-mentioned further solution is that the piston has a reasonable shape design so as to better slide and fit with the volume tube, thereby making it easier to calculate the frictional force between the volume tube and the piston.

[0025] The present invention also relates to a method for measuring friction using the volume tube friction measuring device described above, comprising the following specific steps:

[0026] S1: The piston moves at a constant speed in a straight line under the drive of the servo motor. The piston is in equilibrium under the forces in the direction of motion. According to Newton's second law of motion, we can obtain:

[0027] F f =F+F Z (1)

[0028] In the formula: F is the thrust of the servo motor, in N. f The frictional force between the piston and the volume tube is expressed in N or F. Z The air resistance experienced by the piston is expressed in nanometers (N).

[0029] S2: The torque T of the servo motor can be expressed as a function of the thrust acting on the piston:

[0030]

[0031] Moreover, v = ω·r (3)

[0032] In the formula: ω is the rated speed of the servo motor, in r / s; T is the torque of the servo motor, in N·mm; F ​​is the thrust of the servo motor, in N; v is the movement speed of the piston, in mm / s; I is the current of the servo motor, in mA; a and k are constants; r is the shaft radius of the servo motor, in m;

[0033] From equations (2) and (3) above, it can be seen that the thrust on the piston, i.e. the thrust of the servo motor, is:

[0034]

[0035] S3: The speed at which the piston moves within the volume tube driven by the servo motor is much lower than the speed of the pressure wave within the volume tube, and the piston moves at a constant linear speed within the volume tube driven by the servo motor. Therefore, it can be approximated that the air density within the volume tube is uniform. Thus, the relationship between the air resistance to the piston's movement and the piston's speed is as follows:

[0036] F z =b·v 2 +c·v+d (5)

[0037] In the formula: F z The air resistance experienced by the piston is expressed in N; v is the velocity of the piston, expressed in mm / s; b, c, and d are constants.

[0038] S4: Substituting equations (4) and (5) into equation (1), the simplified and unified expression is as follows:

[0039] F f =a0·I+a1·v 2 +a2·v+a3 (6)

[0040] In the formula: a0, a1, a2, and a3 are constants;

[0041] Due to sliding friction force F f Since the friction force F does not change with the speed of motion, it can be calculated by curve fitting by changing the speed of the piston and measuring the current of the servo motor at the corresponding speed. f ;

[0042] In MATLAB, the polynomial curve fitting command ployfit is used to perform polynomial fitting to obtain the values ​​of a0, a1, a2, and a3, thereby obtaining the specific expression of equation (6) and calculating the sliding friction force of the piston movement inside the volume tube.

[0043] The beneficial effect of adopting the above-mentioned further solutions is that the present invention provides a method for measuring the friction force of a volume tube. The method has a simple structure, reasonable design, can quickly measure the friction force between the piston and the volume tube, is convenient to measure, and has high accuracy. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the present invention;

[0045] Figure 2 This is a flowchart of the measurement process of the present invention.

[0046] The attached diagram lists the components represented by each number as follows:

[0047] 1. Volume tube; 2. Piston; 3. Connecting rod; 4. Slide table; 5. Servo motor; 6. Electronic switch. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] Example 1

[0053] like Figure 1 As shown, this embodiment provides a volume tube friction force measuring device, including a volume tube 1, a piston 2, a sensor, and a controller. The piston 2 is installed inside the volume tube 1 and can move along the axial direction of the volume tube 1. The sensor is fixedly installed on the volume tube 1, and its probe extends into the volume tube 1 and is communicatively connected to the controller. It is used to sense the position of the piston 2 and send the corresponding position signal to the controller. The controller receives the corresponding position signal and calculates the friction force of the volume tube 1.

[0054] During measurement, firstly, the two positions of piston 2 inside volume tube 1 are detected by the sensor, and the corresponding position signals are sent to the controller; then, the controller receives the corresponding position signals and calculates the friction force of the volume tube.

[0055] Preferably, in this embodiment, the volume tube 1 is preferably a circular tubular structure, and connecting flanges are fixedly installed at both ends of it.

[0056] This embodiment has a simple structure and reasonable design, and can quickly measure the frictional force between piston 2 and volume tube 1. The measurement is convenient and highly accurate.

[0057] Example 2

[0058] Based on Embodiment 1, this embodiment also includes a drive component, which is connected to the piston 2 via a transmission component and is used to drive the piston 2 to move.

[0059] During measurement, the piston 2 is driven to move inside the volume tube 1 by the drive component, so as to realize the automatic movement of the piston 2 and measure the friction force of the volume tube 1, which is convenient.

[0060] Example 3

[0061] Based on Embodiment 2, in this embodiment, the transmission component is a connecting rod 3, and the two ends of the connecting rod 3 are fixedly connected to the piston 2 and the drive assembly, respectively.

[0062] The scheme has a simple structure and reasonable design. The connection between piston 2 and drive assembly is achieved through connecting rod 3, which makes the connection convenient.

[0063] Preferably, in this embodiment, the connecting rod 3 is preferably a straight rod structure that extends along the axial direction of the volume tube 1.

[0064] In addition, one end of the connecting rod 3 extends through the corresponding end of the volume tube 1 into the volume tube 1 and is fixedly connected to the piston 2.

[0065] Example 4

[0066] Based on any one of Embodiments 2 to 3, in this embodiment, the driving component includes a slide table 4 and a servo motor 5. The slide table 4 is fixedly installed at one end of the volume tube 1. The servo motor 5 is fixedly installed on the slide table 4, and its driving end extends along the axial direction of the volume tube 1. It is connected to the transmission component through a transmission device and communicates with the controller.

[0067] During measurement, the servo motor 5 rotates and drives the transmission component and the horizontal end of the piston 2 through the transmission device, thereby realizing the automatic movement of the piston 2 so as to measure the friction force of the volume tube 1, which is convenient for measurement.

[0068] Example 5

[0069] Based on Example 4, in this example, the transmission device is a lead screw transmission device, which is mounted on the slide table 4, and the nut on it is fixedly connected to the transmission component.

[0070] The scheme has a simple structure and reasonable design. It uses a screw drive to convert its own rotation into the linear movement of the nut, transmission components and piston 2, which is convenient for transmission.

[0071] Preferably, in this embodiment, the slide 4 is preferably a rectangular plate structure.

[0072] In addition, the slide table 4 is provided with a strip groove that extends along the axial direction of the volume tube 1, and the lead screw in the lead screw drive is installed in the strip groove, which extends along the axial direction of the volume tube 1 and can rotate around its own axial direction; the servo motor 5 is fixed at one end of the strip groove, and its drive end is fixedly connected.

[0073] Example 6

[0074] Based on Example 4, in this example, the transmission device is a synchronous belt transmission device, which is mounted on the slide table 4, and the slider on it is fixedly connected to the transmission component.

[0075] The scheme has a simple structure and reasonable design. It uses a synchronous belt drive to convert the rotation of its own synchronous belt into the linear movement of the slider, transmission components and piston 2 on it, which is convenient for transmission.

[0076] Preferably, in this embodiment, the slide 4 is preferably a rectangular plate structure.

[0077] In addition, the slide table 4 is provided with a strip groove that extends along the axial direction of the volume tube 1, and two pulleys in the synchronous belt drive are installed at both ends of the strip groove in a relatively rotatable manner. The synchronous belt is sleeved on the two pulleys. The servo motor 5 is fixed at one end of the strip groove, and its driving end extends radially along the volume tube 1. One of the pulleys is fixedly sleeved on the driving end of the servo motor 5.

[0078] The above embodiments 5 and 6 are parallel solutions, both of which can realize the transmission of power of the servo motor 5.

[0079] In addition to the above-described embodiments, the drive assembly can also be replaced by other structures. For example, the drive assembly includes a slide 4 and a cylinder. The slide 4 is fixed to the end of the volume tube 1, and the cylinder is fixed on the slide 4. Its telescopic end extends and retracts along the axial direction of the volume tube 1 and is fixedly connected to the piston 2. The piston 2 moves inside the volume tube 1 by the extension and retraction of the cylinder.

[0080] Example 7

[0081] Based on any one of Embodiments 1-6, in this embodiment, the sensor includes a plurality of electronic switches 6, which are fixedly installed on the volume tube 1 at uniform intervals along the axial direction of the volume tube 1, extending into the volume tube 1 respectively, and communicating with the controller respectively.

[0082] During measurement, the position of piston 2 is detected by multiple electronic switches 6 as piston 2 moves, and the corresponding position signals are sent to the controller, making the detection convenient.

[0083] Example 8

[0084] Based on any one of Embodiments 1-6, in this embodiment, the sensor includes multiple position sensors, which are fixedly installed on the volume tube 1 at uniform intervals along the axial direction of the volume tube 1, extending into the volume tube 1 and communicating with the controller.

[0085] During measurement, the position of piston 2 is detected by multiple position sensors as it moves, and the corresponding position signals are sent to the controller, making the detection convenient.

[0086] The above embodiments 7 and 8 are parallel schemes.

[0087] Example 9

[0088] Based on the above embodiments, in this embodiment, the piston 2 has a cylindrical structure, and its edges slide against the inner wall of the volume tube 1.

[0089] The piston 2 is designed with a reasonable shape to better slide and fit with the volume tube 1, thus making it easier to calculate the frictional force between the volume tube 1 and the piston 2.

[0090] Example 10

[0091] Based on the above embodiments, such as Figure 2 As shown, this embodiment also provides a method for measuring friction using the volume tube friction measuring device described above, including the following specific steps:

[0092] S1: Piston 2 moves at a constant speed in a straight line under the drive of servo motor 5. Piston 2 is in equilibrium under the forces in the direction of motion. According to Newton's second law of motion, we can obtain:

[0093] F f =F+F Z (1)

[0094] In the formula: F is the thrust of the servo motor 5, in N. fThe frictional force between the piston 2 and the volume tube 1 is expressed in N or F. Z The air resistance experienced by the piston 2 is expressed in N.

[0095] S2: The torque T of the servo motor 5 can be expressed as a function of the thrust acting on the piston 2:

[0096]

[0097] Moreover, v = ω.r (3)

[0098] In the formula: ω is the rated speed of the servo motor 5, in r / s; T is the torque of the servo motor 5, in N·mm; F ​​is the thrust of the servo motor 5, in N; v is the movement speed of the piston 2, in mm / s; I is the current of the servo motor 5, in mA; a and k are constants; r is the shaft radius of the servo motor 5, in m;

[0099] From equations (2) and (3) above, it can be seen that the thrust on the piston 2, i.e. the thrust of the servo motor 5, is:

[0100]

[0101] S3: The speed at which the piston 2 moves within the volume tube 1 driven by the servo motor 5 is much lower than the speed of the pressure wave within the volume tube 1, and the piston 2 moves in uniform linear motion within the volume tube 1 driven by the servo motor 5. Therefore, it can be approximated that the air density within the volume tube 1 is uniform. Thus, the relationship between the air resistance to the piston 2 and the speed of the piston 2 is as follows:

[0102] F z =b·v 2 +c·v+d (5)

[0103] In the formula: F z The air resistance experienced by piston 2 is expressed in N; v is the velocity of piston 2, expressed in mm / s; b, c, and d are constants.

[0104] S4: Substituting equations (4) and (5) into equation (1), the simplified and unified expression is as follows:

[0105] F f a0·I+a1·v 2 +a2·v+a3 (6)

[0106] In the formula: a0, a1, a2, and a3 are constants;

[0107] Due to sliding friction force F fSince the friction force F does not change with the speed of motion, by changing the speed of the piston 2 and measuring the current of the servo motor 5 at the corresponding speed, the friction force F can be calculated through curve fitting. f ;

[0108] In MATLAB, the polynomial curve fitting command ployfit is used to perform polynomial fitting to obtain the values ​​of a0, a1, a2, and a3, thereby obtaining the specific expression of equation (6) and calculating the sliding friction force of the piston 2 moving inside the volume tube 1.

[0109] This embodiment also provides a method for measuring the frictional force of a volume tube. This method has a simple structure and reasonable design, can quickly measure the frictional force between the piston and the volume tube, is convenient to measure, and has high accuracy.

[0110] The measurement method of the present invention has the following steps:

[0111] S1: Piston 2 moves at a constant speed in a straight line under the drive of servo motor 5. Piston 2 is in equilibrium under the forces in the direction of motion. According to Newton's second law of motion, we can obtain:

[0112] F f =F+F Z (1)

[0113] In the formula: F is the thrust of the servo motor 5, in N. f The frictional force between the piston 2 and the volume tube 1 is expressed in N or F. Z The air resistance experienced by the piston 2 is expressed in N.

[0114] S2: The torque T of the servo motor 5 can be expressed as a function of the thrust acting on the piston 2:

[0115]

[0116] Moreover, v = ω.r (3)

[0117] In the formula: ω is the rated speed of the servo motor 5, in r / s; T is the torque of the servo motor 5, in N·mm; F ​​is the thrust of the servo motor 5, in N; v is the movement speed of the piston 2, in mm / s; I is the current of the servo motor 5, in mA; a and k are constants; r is the shaft radius of the servo motor 5, in m;

[0118] From equations (2) and (3) above, it can be seen that the thrust on the piston 2, i.e. the thrust of the servo motor 5, is:

[0119]

[0120] S3: The speed at which the piston 2 moves within the volume tube 1 driven by the servo motor 5 is much lower than the speed of the pressure wave within the volume tube 1, and the piston 2 moves in uniform linear motion within the volume tube 1 driven by the servo motor 5. Therefore, it can be approximated that the air density within the volume tube 1 is uniform. Thus, the relationship between the air resistance to the piston 2 and the speed of the piston 2 is as follows:

[0121] F z =b·v 2 +c·v+d (5)

[0122] In the formula: F z The air resistance experienced by piston 2 is expressed in N; v is the velocity of piston 2, expressed in mm / s; b, c, and d are constants.

[0123] S4: Substituting equations (4) and (5) into equation (1), the simplified and unified expression is as follows:

[0124] F f =a0·I+a1·v 2 +a2·v+a3 (6)

[0125] In the formula: a0, a1, a2, and a3 are constants;

[0126] Due to sliding friction force F f Since the friction force F does not change with the speed of motion, by changing the speed of the piston 2 and measuring the current of the servo motor 5 at the corresponding speed, the friction force F can be calculated through curve fitting. f ;

[0127] In MATLAB, the polynomial curve fitting command ployfit is used to perform polynomial fitting to obtain the values ​​of a0, a1, a2, and a3, thereby obtaining the specific expression of equation (6) and calculating the sliding friction force of the piston 2 moving inside the volume tube 1.

[0128] It should be noted that all electronic components involved in this invention adopt existing technology, and all the above-mentioned components are electrically connected to the controller, and the control circuit between the controller and each component is existing technology.

[0129] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0130] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring friction force using a volume tube friction force measuring device, characterized in that: The volume tube friction force measuring device includes a volume tube (1), a piston (2), a sensor, and a controller. The piston (2) is installed inside the volume tube (1) and can move along the axial direction of the volume tube (1). The sensor is fixedly installed on the volume tube (1), and its probe extends into the volume tube (1) and is communicatively connected to the controller. It is used to sense the position of the piston (2) and send the corresponding position signal to the controller. The controller receives the corresponding position signal and calculates the friction force of the volume tube (1). The device also includes a drive assembly, which is connected to the piston (2) via a transmission component and is used to drive the piston (2) to move. The drive assembly includes a slide (4) and a servo motor (5). The slide (4) is fixedly installed at one end of the volume tube (1). The servo motor (5) is fixedly installed on the slide (4), and its drive end extends along the axial direction of the volume tube (1) and is connected to the transmission component via a transmission component and is communicatively connected to the controller. The method for measuring friction includes the following specific steps: S1: The piston (2) moves in uniform linear motion under the drive of the servo motor (5). The piston (2) is in equilibrium in the direction of motion. According to Newton's second law of motion, we can obtain: （1） In the formula: F is the thrust of the servo motor (5), in N. The frictional force between the piston (2) and the volume tube (1) is expressed in N. The air resistance experienced by the piston (2) is expressed in N. S2: The torque T of the servo motor (5) can be expressed as a function of the thrust on the piston (2): （2） and (3) In the formula: Rated speed of the servo motor (5) in r / s; torque of the servo motor (5) in N·mm; thrust of the servo motor (5) in N; and velocity of the piston (2) in mm / s. The current of the servo motor (5) is mA; a and k are constants; r is the shaft radius of the servo motor (5) in meters. From equations (2) and (3) above, it can be seen that the thrust on the piston (2), which is the thrust of the servo motor (5), is: （4） S3: The speed at which the piston (2) driven by the servo motor (5) moves within the volume tube (1) is much lower than the speed of the pressure wave within the volume tube (1), and the piston (2) driven by the servo motor (5) moves in uniform linear motion within the volume tube (1). It is approximately assumed that the air density within the volume tube (1) is the same. Therefore, the relationship between the air resistance to the movement of the piston (2) and the speed of the piston (2) is as follows: （5） In the formula: The air resistance experienced by the piston (2) is in N; v is the speed of the piston (2) in mm / s. , and They are constants; S4: Substituting equations (4) and (5) into equation (1), the simplified and unified expression is as follows: （6） In the formula: , , and They are constants; Due to sliding friction Since the friction force does not change with the speed of motion, by changing the speed of the piston (2) and measuring the current of the servo motor (5) at the corresponding speed, the friction force can be calculated by curve fitting. ; In MATLAB, the polynomial curve fitting command `polyfit` is used to perform polynomial fitting to obtain... , , , The value can be used to obtain the specific expression of equation (6), and then the sliding friction force of the piston (2) moving inside the volume tube (1) can be calculated.

2. The method for measuring friction force using a volume tube friction force measuring device according to claim 1, characterized in that: The transmission component is a connecting rod (3), and the two ends of the connecting rod (3) are fixedly connected to the piston (2) and the drive assembly, respectively.

3. The method for measuring friction using a volume tube friction measuring device according to claim 1, characterized in that: The transmission device is a lead screw transmission device, which is installed on the slide table (4), and the nut on it is fixedly connected to the transmission component.

4. The method for measuring friction force using a volume tube friction force measuring device according to claim 1, characterized in that: The transmission device is a synchronous belt transmission device, which is installed on the slide table (4), and the slider on it is fixedly connected to the transmission component.

5. The method for measuring friction force using a volume tube friction force measuring device according to any one of claims 1-4, characterized in that: The sensor includes multiple electronic switches (6), which are fixedly installed on the volume tube (1) at uniform intervals along the axial direction of the volume tube (1), extending into the volume tube (1) and communicating with the controller.

6. The method for measuring friction using a volume tube friction measuring device according to any one of claims 1-4, characterized in that: The sensor includes multiple position sensors, which are fixedly installed on the volume tube (1) at uniform intervals along the axial direction of the volume tube (1), extending into the volume tube (1) and communicating with the controller.

7. The method for measuring friction force using a volume tube friction force measuring device according to any one of claims 1-4, characterized in that: The piston (2) has a cylindrical structure, and its edges slide against the inner wall of the volume tube (1).

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