Inner diameter measuring device and use method thereof

Abstract

The invention relates to the technical field of measuring equipment, and particularly discloses an inner diameter measuring device and a use method thereof.The inner diameter measuring device comprises a mounting shell, an adjustable contact, a moving contact, a displayer and a protective bridge; the adjustable contact is movably arranged in the mounting shell along the axial direction; one end of the adjustable contact is provided with an adjustable contact point, and the other end of the adjustable contact is connected with one of a scale strip and a reader; the moving contact is elastically arranged in the mounting shell along the axial direction; one end of the moving contact is provided with a moving contact, and the other end of the moving contact is connected with the other one of the reader and the scale strip; the protective bridge is elastically arranged outside the installation shell in the axial direction. When the inner diameters of to-be-measured inner holes of different specifications are measured, three-point positioning can be formed through the adjustable contact and the two positioning contacts, the to-be-measured inner diameters can be conveniently, rapidly and accurately found, the time required for measurement is shortened, a standard inner diameter ring gauge does not need to be found for setting a basic zero position, continuous setting and correction are avoided, and the measurement difficulty is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring equipment, and in particular to an inner diameter measuring device and a use method thereof. Background Art

[0002] A length measuring device is a tool used to measure length. The basic principle is to compare the length to be measured with the known length to obtain the measurement result. These tools are widely used in science, technology, engineering and daily life. When machining internal holes, it is necessary to measure the internal hole diameter frequently to determine whether the machining size meets the drawing requirements.

[0003] At present, the inner hole is generally measured by an inner diameter gauge. In the prior art, the measuring range of the inner diameter gauge is limited, and it can only measure the aperture with a small deviation from the set value. When it is used for inner diameter measurement, it must be calibrated before each use. It is necessary to find a standard inner diameter ring gauge close to the target size to set the basic zero position. When measuring, you can only see how much larger or smaller it is than the zero value. Therefore, when facing inner holes of different specifications, it needs to be constantly set and calibrated before use, which makes measurement difficult. Summary of the invention

[0004] The purpose of the present invention is to provide an inner diameter measuring device and a method of using the same, so as to solve the problem that the measuring range of the inner diameter gauge in the prior art is limited and can only measure the aperture with a small deviation from the set value, and when measuring, only how much larger or smaller than the zero value can be seen. Therefore, when facing inner holes of different specifications, continuous settings and calibrations are required before use, which in turn causes measurement difficulties.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides an inner diameter measuring device, comprising:

[0007] A mounting shell, wherein a movable opening is formed on one side of the mounting shell along an axial direction;

[0008] An adjustable contact, the adjustable contact is movably arranged in the mounting housing along the axial direction; one end of the adjustable contact has an adjustable contact point, the adjustable contact point passes through the movable opening to the outside, and the other end of the adjustable contact is connected to one of a scale bar or a reader; the length of the adjustable contact along the axial direction is adjustable;

[0009] A moving contact, wherein the moving contact is elastically arranged in the mounting housing along the axial direction; one end of the moving contact has a moving contact point, and the moving contact point can pass through the mounting housing to the outside, and the other end of the moving contact is connected to the other of the reader or the scale bar, and the reader is used to read the scale bar; the adjustable contact point and the moving contact are located on opposite sides of the mounting housing along the axial direction;

[0010] A guard bridge, wherein the guard bridge is elastically arranged outside the mounting housing along the axial direction; at least two positioning contacts are arranged at one end of the guard bridge away from the adjustable contact, and the connection line between at least two of the positioning contacts and the adjustable contact can form an isosceles triangle;

[0011] A display is communicatively connected to the reader and is used to display the distance between the adjustable contact and the moving contact.

[0012] As an optional solution of the above-mentioned inner diameter measuring device, the adjustable contact includes a movable seat and a joint, part of the movable seat is movably arranged in the mounting shell, and the other part of the movable seat is located outside the mounting shell, and the joint is detachably connected to one end of the movable seat away from the moving contact.

[0013] As an optional solution of the above inner diameter measuring device, the adjustable contact further includes a connecting rod, and opposite ends of the connecting rod are detachably connected to the movable seat and the joint respectively; the connecting rod is extended along the axial direction.

[0014] As an optional solution of the above inner diameter measuring device, the adjustable contact further includes a locking member, which can pass through the mounting shell along the radial direction of the mounting shell and be crimped to the movable seat.

[0015] As an optional scheme of the above-mentioned inner diameter measuring device, the inner diameter measuring device also includes a first elastic member, the inner wall of the mounting shell is provided with a first limiting step, and the opposite ends of the first elastic member are respectively abutted against the first limiting step and the moving contact, so that the moving contact always has a tendency to move away from the adjustable contact.

[0016] As an optional solution of the above-mentioned inner diameter measuring device, the inner diameter measuring device also includes a second elastic member, the outer wall of the mounting shell is provided with a second limiting step, and the opposite ends of the second elastic member are respectively abutted against the second limiting step and the guard bridge, so that the guard bridge always has a tendency to move away from the adjustable contact.

[0017] As an optional solution of the above-mentioned inner diameter measuring device, the mounting shell includes a main shell and a cover shell, the main shell is respectively provided with the movable opening and the mounting opening at both ends along the axial direction, the cover shell is detachably connected to the mounting opening, and the moving contact can pass through the cover shell to the outside.

[0018] As an optional solution of the above inner diameter measuring device, a handle bar is vertically arranged on the mounting shell.

[0019] As an optional solution of the above inner diameter measuring device, the display is arranged on the mounting housing or on the handle bar or is arranged separately.

[0020] On the other hand, the present invention provides a method for using an inner diameter measuring device, which is performed using the inner diameter measuring device as described above. The method for using the inner diameter measuring device comprises the following steps:

[0021] The adjustable contact is moved to adjust the position of the adjustable contact on the mounting housing, and the length of the adjustable contact is adjusted so that the spacing between the adjustable contact and the movable contact is larger than the inner diameter of the inner hole to be measured;

[0022] The adjustable contact of the adjustable contact is abutted against the inner wall of one side of the inner hole to be measured, and at least two positioning contacts of the protection bridge are abutted against the inner wall of the other side of the inner hole to be measured;

[0023] While maintaining the adjustable contact and at least two positioning contacts in continuous contact with the inner wall of the inner hole to be measured, so that the cross-section of the inner hole to be measured along the axial direction always includes the line segment formed by the adjustable contact and the moving contact, the moving contact of the moving contact is moved along the axial direction of the inner hole to be measured, and the minimum value of the measurement is selected through the display.

[0024] The beneficial effects of the present invention are:

[0025] The inner diameter measuring device comprises a mounting shell, an adjustable contact, a moving contact, a display and a protective bridge. A movable opening is provided on one side of the mounting shell along the axial direction, and the adjustable contact is movably arranged in the mounting shell along the axial direction. One end of the adjustable contact has an adjustable contact point, and the adjustable contact point passes through the moving opening to the outside, and the other end of the adjustable contact is connected to one of a scale bar or a reader, so that after adjusting the position of the adjustable contact on the mounting shell, the initial position of the adjustable contact point and the scale bar or the reader can be adjusted.

[0026] The movable contact is elastically arranged in the mounting shell along the axial direction, and one end of the movable contact has a movable contact point, which can pass through the mounting shell to the outside world. The other end of the movable contact is connected to the other of the reader or the scale bar, and the reader is used to read the scale bar. The adjustable contact point and the movable contact point are located on opposite sides of the mounting shell along the axial direction, so that when measuring the inner diameter of the inner hole to be measured, the relative position of the reader and the scale bar can be adjusted by the abutment of the adjustable contact point and the movable contact point on the wall of the inner hole to be measured, and then the distance between the adjustable contact point and the movable contact point can be directly measured to determine the aperture of the inner hole to be measured. This process can make the movable contact point automatically extend and retract along the axial direction through the elastic movement setting of the movable contact point, so as to realize the automatic adjustment of the distance between the adjustable contact point and the movable contact point. Among them, the display is connected to the reader for displaying the distance between the adjustable contact point and the movable contact point. Therefore, when measuring the inner diameter of the inner hole to be measured of different specifications, there is no need to find a standard inner diameter ring gauge to set the basic zero position, thereby avoiding continuous setting and correction, and reducing the difficulty of measurement.

[0027] Among them, the guard bridge is elastically arranged outside the installation shell along the axial direction, and at least two positioning contacts are arranged at one end of the guard bridge away from the adjustable contact. The connecting lines of at least two positioning contacts and the adjustable contact can form an isosceles triangle, so that the adjustable contact and the two positioning contacts can form three-point positioning, which is convenient for quickly and accurately finding the inner diameter to be measured and reducing the time required for measurement.

[0028] At the same time, the axial length of the adjustable contact can be adjusted, and the adjustable contact can be movably arranged in the mounting shell along the axial direction, so that by adjusting the position of the adjustable contact on the mounting shell and the length of the adjustable contact itself, the inner diameter of a large hole or a small hole can be measured.

[0029] The method for using the inner diameter measuring device of the present invention is completed using the inner diameter measuring device as described above. The method for using the inner diameter measuring device is simple and convenient to use, has accurate measurement, large range adaptability, and is easily accepted by on-site staff. By adjusting the position of the adjustable contact on the mounting shell and adjusting the length of the adjustable contact itself, it can meet the measurement of inner holes to be measured of different specifications. The three-point positioning can be formed by the adjustable contact and the two positioning contacts, which is convenient for quickly and accurately finding the inner diameter to be measured, reducing the time required for measurement, and the display directly displays the measured value during measurement, without the need to find a standard inner diameter ring gauge to set the basic zero position, thereby avoiding continuous setting and correction and reducing the difficulty of measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A cross-sectional view of an inner diameter measuring device provided by an embodiment of the present invention;

[0031] Figure 2 A cross-sectional view of another inner diameter measuring device provided by an embodiment of the present invention;

[0032] Figure 3 A top view of an inner diameter measuring device provided by an embodiment of the present invention;

[0033] Figure 4 A schematic flow chart of a method for using the inner diameter measuring device provided in an embodiment of the present invention.

[0034] In the figure:

[0035] 1. Install the shell; 11. Move the opening; 12. The first limit step; 13. The second limit step; 14. The main shell; 141. Install the opening; 15. The cover shell; 16. The handle bar; 2. The adjustable contact; 21. The adjustable contact point; 22. The scale bar; 23. The movable seat; 24. The joint; 25. The connecting rod; 26. The locking piece; 3. The moving contact; 31. The moving contact point; 32. The reader; 4. The display; 5. The first elastic piece; 6. The guard bridge; 61. The positioning contact point; 7. The second elastic piece; 8. The inner hole to be measured. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0037] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0040] like Figure 1 to Figure 3 As shown, this embodiment provides an inner diameter measuring device for measuring the inner diameter of the inner hole 8 to be measured.

[0041] The inner diameter measuring device comprises a mounting housing 1, an adjustable contact 2, a moving contact 3, a display 4 and a protective bridge 6. A movable opening 11 is provided on one side of the mounting housing 1 along the axial direction, and the adjustable contact 2 is movably arranged in the mounting housing 1 along the axial direction, and one end of the adjustable contact 2 has an adjustable contact 21, and the adjustable contact 21 passes through the movable opening 11 to the outside, and the other end of the adjustable contact 2 is connected to one of the scale bar 22 or the reader 32, so that after adjusting the position of the adjustable contact 2 on the mounting housing 1, the initial positions of the adjustable contact 21 and the scale bar 22 or the reader 32 can be adjusted.

[0042] The moving contact 3 is elastically arranged in the mounting shell 1 along the axial direction, and one end of the moving contact 3 has a moving contact 31, and the moving contact 31 can pass through the mounting shell 1 to the outside world. The other end of the moving contact 3 is connected to the other of the reader 32 and the scale bar 22, and the reader 32 is used to read the scale bar 22. The adjustable contact 21 and the moving contact 31 are axially located on opposite sides of the mounting shell 1. Therefore, when measuring the inner diameter of the inner hole 8 to be measured, the relative position of the reader 32 and the scale bar 22 can be adjusted through the abutment of the adjustable contact 21 and the moving contact 31 on the hole wall of the inner hole 8 to be measured, and then the distance between the adjustable contact 21 and the moving contact 31 can be directly measured to determine the aperture of the inner hole 8 to be measured. This process can make the moving contact 31 automatically expand and contract along the axial direction through the elastic movement setting of the moving contact 31, thereby realizing the automatic adjustment of the distance between the adjustable contact 21 and the moving contact 31. The display is communicatively connected to the reader 32 to display the distance between the adjustable contact 21 and the moving contact 31. Therefore, when measuring the inner diameter of the inner hole 8 of different specifications, there is no need to find a standard inner diameter ring gauge to set the basic zero position, thereby avoiding continuous setting and correction and reducing the difficulty of measurement. Optionally, the communication connection includes a wired communication connection and a wireless communication connection.

[0043] Among them, the guard bridge 6 is elastically arranged outside the mounting shell 1 along the axial direction, and at least two positioning contacts 61 are arranged at one end of the guard bridge 6 away from the adjustable contact 2. The connecting line of at least two positioning contacts 61 and the adjustable contact 21 can form an isosceles triangle, so that the adjustable contact 21 and the two positioning contacts 61 can form a three-point positioning, which is convenient for quickly and accurately finding the inner diameter to be measured and reducing the time required for measurement.

[0044] At the same time, the length of the adjustable contact 2 along the axial direction can be adjusted, and the adjustable contact 2 can be movably arranged in the mounting housing 1 along the axial direction, so that by adjusting the position of the adjustable contact 2 on the mounting housing 1 and the length of the adjustable contact 2 itself, the inner diameter of the large hole or the small hole can be measured. Optionally, a handle bar 16 is vertically arranged on the mounting housing 1, so that the staff can move the inner diameter measuring device by holding the handle bar 16 to adjust the position of the inner diameter measuring device, thereby reducing the difficulty of the inner diameter measuring device to measure the inner hole 8 to be measured. Further optionally, the display 4 is arranged on the mounting housing 1 or on the handle bar 16 or is arranged separately, so that the inner diameter measuring device is divided into different types according to the position of the display 4, so as to meet different working conditions.

[0045] like Figure 1 and Figure 2As shown, the adjustable contact 2 includes a moving seat 23 and a connector 24, a part of the moving seat 23 is movably arranged in the mounting housing 1, and another part of the moving seat 23 is located outside the mounting housing 1, and the connector 24 is detachably connected to one end of the moving seat 23 away from the moving contact 3, so that by moving the moving seat 23 and replacing the connector 24, the measuring range of the inner diameter measuring device can be adjusted. In another embodiment, the adjustable contact 2 also includes a connecting rod 25, the opposite ends of the connecting rod 25 are detachably connected to the moving seat 23 and the connector 24, respectively, and the connecting rod 25 is extended in the axial direction, so that by setting the connecting rod 25, the measuring range of the inner diameter measuring device can be further expanded, so that the inner diameter measuring device can measure inner holes with larger inner diameters to meet the actual working conditions.

[0046] Furthermore, the adjustable contact 2 further includes a locking member 26, which can pass through the mounting housing 1 along the radial direction of the mounting housing 1 and be crimped to the moving seat 23, so that the moving seat 23 is locked to prevent the moving seat 23 from being displaced during the measurement process and causing measurement failure. Optionally, the locking member 26 is a locking screw, so that by rotating the locking screw, the locking screw can be moved relative to the mounting housing 1, which facilitates locking of the moving seat 23.

[0047] Further, the inner diameter measuring device also includes a first elastic member 5, and the inner wall of the mounting housing 1 is provided with a first limiting step 12, and the opposite ends of the first elastic member 5 are respectively abutted against the first limiting step 12 and the moving contact 3, so that the moving contact 3 always has a tendency to move away from the adjustable contact 2, so that when the moving contact 3 initially abuts against the inner wall of the inner hole 8 to be measured, the moving contact 3 is abutted and the first elastic member 5 is compressed, and after the positions of the adjustable contact 21 and the moving contact 31 are adjusted to find the inner diameter to be measured, the first elastic member 5 can rebound to drive the moving contact 3 to extend out of the mounting housing 1, thereby realizing automatic adjustment of the position of the moving contact 31. Optionally, the first elastic member 5 is a spring.

[0048] The inner diameter measuring device also includes a second elastic member 7, and the outer wall of the mounting housing 1 is provided with a second limiting step 13. The opposite ends of the second elastic member 7 are respectively abutted against the second limiting step 13 and the guard bridge 6, so that the guard bridge 6 always has a movement tendency away from the adjustable contact 2, so that when the positioning contact 61 initially abuts against the inner wall of the inner hole 8 to be measured, the guard bridge 6 is abutted and the second elastic member 7 is compressed. After adjusting the positions of the adjustable contact 21 and the moving contact 31 to find the inner diameter to be measured, the second elastic member 7 can rebound to drive the guard bridge 6 to extend out of the mounting housing 1, thereby realizing automatic adjustment of the three-point positioning. Optionally, the second elastic member 7 is a spring.

[0049] Furthermore, the installation housing 1 includes a main housing 14 and a cover housing 15, and the main housing 14 is provided with a moving opening 11 and an installation opening 141 at both ends along the axial direction, and the cover housing 15 is detachably connected to the installation opening 141, and the moving contact 31 can pass through the cover housing 15 to the outside, so that the detachable connection between the cover housing 15 and the main housing 14 can facilitate the staff to install the internal components of the inner diameter measuring device, reduce the production difficulty, and also facilitate the disassembly and maintenance of the inner diameter measuring device. Optionally, the cover housing 15 can abut against the moving contact 3 and the guard bridge 6 respectively along the axial direction to prevent the moving contact 3 and the guard bridge 6 from detaching from the main housing 14.

[0050] This embodiment also provides a method for using the inner diameter measuring device, which is completed using the inner diameter measuring device as described above. Figure 4 As shown, the method for using the inner diameter measuring device includes the following steps:

[0051] By moving the adjustable contact 2 to adjust the position of the adjustable contact 2 on the mounting housing 1, and adjusting the length of the adjustable contact 2, the distance between the adjustable contact 21 and the movable contact 31 is larger than the inner diameter of the inner hole 8 to be measured;

[0052] The adjustable contact 21 of the adjustable contact 2 is abutted against the inner wall of one side of the inner hole 8 to be tested, and at least two positioning contacts 61 of the protective bridge 6 are abutted against the inner wall of the other side of the inner hole 8 to be tested;

[0053] While keeping the adjustable contact 21 and at least two positioning contacts 61 in continuous contact with the inner wall of the inner hole 8 to be measured, so that the cross-section of the inner hole 8 to be measured along the axial direction always includes the line segment formed by the adjustable contact 21 and the moving contact 31, the moving contact 31 of the moving contact 3 is moved along the axial direction of the inner hole 8 to be measured, and the minimum value of the measurement is selected through the display 4.

[0054] The method for using the inner diameter measuring device in this embodiment is completed using the inner diameter measuring device as described above. The method for using the inner diameter measuring device is simple and convenient to use, has accurate measurement, and has a large range adaptability, and is easily accepted by on-site staff. By adjusting the position of the adjustable contact 2 on the mounting housing 1 and adjusting the length of the adjustable contact 2 itself, it can meet the measurement of inner holes 8 to be measured of different specifications. The three-point positioning can be formed by the adjustable contact 21 and the two positioning contacts 61, which is convenient for quickly and accurately finding the inner diameter to be measured, reducing the time required for measurement, and the display 4 directly displays the measured value during measurement, without the need to find a standard inner diameter ring gauge to set the basic zero position, thereby avoiding continuous setting and correction and reducing the difficulty of measurement.

[0055] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An inner diameter measuring device, characterized in that: include: A mounting shell (1), wherein a movable opening (11) is provided on one side of the mounting shell (1) along the axial direction; An adjustable contact (2), the adjustable contact (2) being movably arranged in the mounting housing (1) along the axial direction; one end of the adjustable contact (2) having an adjustable contact point (21), the adjustable contact point (21) passing through the movable opening (11) to the outside, the other end of the adjustable contact (2) being connected to one of a scale bar (22) or a reader (32); the length of the adjustable contact (2) along the axial direction being adjustable; A moving contact (3), wherein the moving contact (3) is elastically arranged in the mounting housing (1) along the axial direction; one end of the moving contact (3) has a moving contact point (31), and the moving contact point (31) can pass through the mounting housing (1) to the outside, and the other end of the moving contact (3) is connected to the other of the reader (32) and the scale bar (22), and the reader (32) is used to read the scale bar (22); the adjustable contact point (21) and the moving contact point (31) are located on opposite sides of the mounting housing (1) along the axial direction; A protection bridge (6), the protection bridge (6) being elastically arranged outside the mounting housing (1) along the axial direction; at least two positioning contacts (61) are arranged at one end of the protection bridge (6) away from the adjustable contact (2), and a line connecting at least two of the positioning contacts (61) and the adjustable contact (21) can form an isosceles triangle; A display (4), the display (4) is communicatively connected to the reader (32) and is used to display the distance between the adjustable contact (21) and the movable contact (31).

2. The inner diameter measuring device according to claim 1, characterized in that: The adjustable contact (2) comprises a movable seat (23) and a connector (24); a portion of the movable seat (23) is movably disposed within the mounting housing (1), and another portion of the movable seat (23) is located outside the mounting housing (1); and the connector (24) is detachably connected to one end of the movable seat (23) away from the movable contact (3).

3. The inner diameter measuring device according to claim 2, characterized in that: The adjustable contact (2) further comprises a connecting rod (25), the opposite ends of which are detachably connected to the movable seat (23) and the joint (24), respectively; the connecting rod (25) is extended along the axial direction.

4. The inner diameter measuring device according to claim 2, characterized in that: The adjustable contact (2) further comprises a locking member (26), wherein the locking member (26) can pass through the mounting housing (1) in a radial direction of the mounting housing (1) and be crimped onto the movable seat (23).

5. The inner diameter measuring device according to claim 1, characterized in that: The inner diameter measuring device further comprises a first elastic member (5), the inner wall of the mounting housing (1) is provided with a first limiting step (12), and opposite ends of the first elastic member (5) respectively abut against the first limiting step (12) and the moving contact (3), so as to ensure that the moving contact (3) always has a tendency to move away from the adjustable contact (2).

6. The inner diameter measuring device according to claim 1, characterized in that: The inner diameter measuring device further comprises a second elastic member (7), the outer wall of the mounting housing (1) is provided with a second limiting step (13), and opposite ends of the second elastic member (7) respectively abut against the second limiting step (13) and the guard bridge (6), so as to ensure that the guard bridge (6) always has a tendency to move away from the adjustable contact (2).

7. The inner diameter measuring device according to any one of claims 1 to 6, characterized in that: The installation shell (1) comprises a main shell (14) and a cover shell (15); the main shell (14) is provided with the movable opening (11) and the installation opening (141) at two ends along the axial direction respectively; the cover shell (15) is detachably connected to the installation opening (141), and the movable contact (31) can pass through the cover shell (15) to the outside.

8. The inner diameter measuring device according to any one of claims 1 to 6, characterized in that: A handle bar (16) is vertically arranged on the mounting housing (1).

9. The inner diameter measuring device according to claim 8, characterized in that: The display (4) is arranged on the installation housing (1) or on the handle bar (16) or is arranged separately.

10. A method for using an inner diameter measuring device, characterized in that: The inner diameter measuring device according to any one of claims 1 to 9 is used, and the method for using the inner diameter measuring device comprises the following steps: The adjustable contact (2) is moved to adjust the position of the adjustable contact (2) on the mounting housing (1), and the length of the adjustable contact (2) is adjusted so that the distance between the adjustable contact point (21) and the movable contact point (31) is greater than the inner diameter of the inner hole (8) to be measured; The adjustable contact (21) of the adjustable contact (2) is abutted against the inner wall of one side of the inner hole (8) to be measured, and at least two positioning contacts (61) of the protective bridge (6) are abutted against the inner wall of the other side of the inner hole (8) to be measured; While maintaining the adjustable contact (21) and at least two positioning contacts (61) in continuous contact with the inner wall of the inner hole (8) to be measured, so that the cross section of the inner hole (8) to be measured along the axial direction always includes the line segment formed by the adjustable contact (21) and the movable contact (31), the movable contact (31) of the movable contact (3) is moved along the axial direction of the inner hole (8) to be measured, and the minimum value of the measurement is selected through the display (4).

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