Clamping length measuring device and method

Abstract

The invention provides a clamping length measuring device and method, and relates to the technical field of mechanical measurement. The device comprises a positioning screw rod, a connecting screw rod and a measuring mechanism, the positioning screw comprises a screw part and a polished rod part, the outer side wall of the screw part is provided with an external thread matched with an internal thread of a connecting pair nut of a to-be-measured threaded connecting pair, and the diameter of the polished rod part is larger than the inner diameter of the external thread of the screw part and smaller than or equal to the outer diameter of the external thread of the screw part; the first end of the connecting screw rod is provided with an external thread matched with the internal thread of the internal thread blind hole; the measuring structure is used for monitoring the position of the second end of the connecting screw rod in the connecting part when the connecting part sleeves the connecting screw rod, so as to display the clamping length of the to-be-measured threaded connection pair based on the position. According to the clamping length measuring device, through the positioning screw rod, the connecting screw rod and the measuring mechanism, real assembly of a threaded connection pair can be simulated, and the accuracy of clamping length measurement of the threaded connection pair is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical measurement, and in particular to a clamping length measuring device and method. Background Art

[0002] A complete vehicle requires a large number of fasteners, and threaded connections are the most common type of connection used in these fasteners. In the forward development stage of vehicle models, a large number of joint tests are required for key parts of the vehicle, especially those related to vehicle safety and comfort, to support the development of tightening processes and verify the safety and reliability of the connection parts, while providing data support for the subsequent necessary tightening process adjustments. Before conducting joint tests, it is necessary to calibrate the threaded fasteners such as bolts used in threaded connections in advance. Based on the calibration data, the tightening process of the threaded connection pair using the threaded fastener or the clamping force value of the connection part under a certain tightening process can be output. Among them, an important factor affecting the calibration of threaded fasteners is the clamping length. The closer the clamping length obtained in the calibration process matches the actual clamping length of the threaded connection pair, the higher the accuracy of the test data. Therefore, the measurement of the clamping length is particularly important for the calibration of threaded fasteners and even the accuracy of joint tests.

[0003] The clamping length of a threaded connection pair generally refers to the distance between the supporting surface of the bolt and the supporting surface of the nut used in the threaded connection pair. However, if the internal threaded hole of the nut has a chamfer, the length of the chamfered part on the axis of the nut should also be included in the clamping length of the threaded connection pair. In short, the clamping length of a threaded connection pair is the distance from the supporting surface of the bolt used in the threaded connection pair to the first tooth of the nut. In the traditional clamping length measurement method, a vernier caliper is used to directly measure the length of each clamping part of the threaded connection pair, and the total clamping length is obtained by superposition. Although this measurement method is relatively accurate and fast for measuring parts with a single structure and regular shape, it has the following problems:

[0004] 1. For parts with complex structures and irregular shapes such as vehicle chassis parts, due to position interference and unstable force points of the vernier caliper, continuing to use the vernier caliper for measurement will result in low measurement efficiency and difficulty in ensuring measurement accuracy;

[0005] 2. The total clamping length is obtained by measuring the length of each clamping part of the threaded connection pair and superimposing them. This cannot reflect the actual clamping length of the threaded connection pair during assembly, resulting in a large error.

[0006] All of the above will affect the accuracy of measuring the clamping length of the threaded connection pair. Summary of the invention

[0007] The problem solved by the invention is how to improve the accuracy of measuring the clamping length of a threaded connection pair.

[0008] In order to solve the above problems, the present invention provides a clamping length measuring device and method.

[0009] In a first aspect, the present invention provides a clamping length measuring device, which is used to measure the clamping length of a threaded connection pair to be measured, wherein the threaded connection pair to be measured includes a connection pair nut, and the clamping length measuring device includes:

[0010] A positioning screw, the positioning screw comprising a screw portion and a smooth rod portion which are integrally formed and coaxially arranged, an outer wall of the screw portion is provided with an external thread adapted to match the internal thread of the connecting pair nut, a diameter of the smooth rod portion is larger than an inner diameter of the external thread of the screw portion and smaller than or equal to an outer diameter of the external thread of the screw portion, and an end of the smooth rod portion away from the screw portion is provided with an internal thread blind hole;

[0011] A connecting screw, wherein the first end of the connecting screw is provided with an external thread matching the internal thread of the internal thread blind hole;

[0012] A measuring mechanism, the measuring mechanism includes a hollow connecting portion and a measuring structure arranged on the connecting portion, the measuring structure is used to monitor the position of the second end of the connecting screw in the connecting portion when the connecting portion is sleeved on the connecting screw, so as to display the clamping length of the threaded connection pair to be measured based on the position.

[0013] Optionally, the clamping length measuring device further comprises a fixing nut, the internal thread of the fixing nut is adapted to the external thread of the connecting screw, and the end faces of the fixing nut at both ends of its own axis are perpendicular to its own axis.

[0014] Optionally, the connecting portion includes a first columnar portion, and the first columnar portion is provided with an accommodating hole for accommodating the connecting screw;

[0015] Or, the connecting portion includes a first columnar portion and a second columnar portion that are integrally formed and coaxially arranged, the first columnar portion is provided with a receiving hole, the second columnar portion is provided with a through hole connected to the receiving hole, the connected receiving hole and the through hole are used to accommodate the connecting screw, and the diameter of the through hole is greater than or equal to the diameter of the bare rod portion, and the axial length of the second columnar portion is greater than or equal to the axial length of the bare rod portion.

[0016] Optionally, an outer side wall of the connecting screw is provided with an external thread, and the external thread of the connecting screw extends from the first end to the second end of the connecting screw;

[0017] The accommodating hole is a cylindrical hole, and the diameter of the cylindrical hole is greater than or equal to the outer diameter of the external thread of the connecting screw; or, the accommodating hole is a cylindrical hole, and the hole wall of the cylindrical hole is provided with an internal thread for matching with the external thread of the connecting screw.

[0018] Optionally, the clamping length measuring device also includes a standard nut, the internal thread of the standard nut is adapted to the external thread of the screw portion, the end faces of the standard nut at both ends of its own axis are perpendicular to its own axis, and the two ends of the internal thread of the standard nut are respectively flush with the end faces of the standard nut at both ends of its own axis.

[0019] Optionally, the measuring structure comprises a distance measuring structure, and the distance measuring structure is used to measure the distance between one end of the connecting screw extending into the connecting part and a fixed reference point on the connecting part on the axis of the connecting part;

[0020] Alternatively, the measuring structure comprises a displacement measuring structure, and the displacement measuring structure is used to measure the length of the connecting screw extending into the connecting part along the axis of the connecting part.

[0021] Optionally, the measuring mechanism further comprises a display structure communicatively connected to the measuring structure, wherein the display structure is used to display the clamping length of the threaded connection pair to be measured.

[0022] In a second aspect, the present invention provides a clamping length measurement method. Based on the clamping length measurement device as described in the first aspect, the clamping length measurement method comprises:

[0023] Select a positioning screw that matches the connection nut of the threaded connection to be measured;

[0024] Screw the positioning screw completely into the connecting nut;

[0025] Connecting the positioning screw to the first end of the connecting screw;

[0026] Sleeve the connected member of the threaded connection pair to be measured onto the connecting screw;

[0027] The measuring mechanism after the zeroing operation is sleeved on the connecting screw from the second end of the connecting screw, and the connecting portion of the measuring mechanism and the connecting nut are clamped on the connected member, and the second position of the second end of the connecting screw in the connecting portion is obtained through the measuring structure of the measuring mechanism;

[0028] According to the second position, the clamping length of the threaded connection pair to be measured is determined.

[0029] Optionally, the connected member of the threaded connection pair to be measured is sleeved behind the connecting screw, and the measuring mechanism after the zeroing operation is sleeved from the second end of the connecting screw to the front of the connecting screw, and the clamping length measurement method further includes:

[0030] Sleeve a fixing nut on the connecting screw from the second end of the connecting screw, and make the fixing nut and the connecting auxiliary nut clamp the connected member;

[0031] Determining the clamping length of the threaded connection pair to be measured according to the second position includes:

[0032] The clamping length of the threaded connection pair to be measured is determined according to the second position and the axial length of the fixing nut.

[0033] Optionally, after selecting a positioning screw that matches the connection pair nut of the threaded connection pair to be measured and before completely screwing the positioning screw into the connection pair nut, the clamping length measurement method further includes:

[0034] Select a standard nut that matches the positioning screw;

[0035] Screw the positioning screw completely into the standard nut;

[0036] Connecting the positioning screw to the first end of the connecting screw;

[0037] The measuring mechanism is sleeved on the connecting screw from the second end of the connecting screw, and the connecting portion of the measuring mechanism is brought into contact with the standard nut, and a first position of the second end of the connecting screw in the connecting portion is obtained through the measuring structure;

[0038] The first position is set as a reference position, and a zeroing operation is performed on the measuring mechanism.

[0039] The beneficial effects of the clamping length measuring device of the present invention are as follows: the clamping length measuring device of the present invention is provided with a positioning screw including a screw portion and a smooth rod portion that are integrally formed and coaxially arranged, and the diameter of the smooth rod portion is larger than the inner diameter of the external thread of the screw portion, so that the positioning screw can limit the screw portion by the smooth rod portion when it is screwed into the connecting pair nut, ensuring that when the positioning screw is fully screwed into the connecting pair nut, the smooth rod portion can abut against the end of the internal thread of the connecting pair nut. On the one hand, the relative position of the connecting pair nut and the positioning screw is limited, avoiding measurement errors caused by changes in the relative positions of the connecting screw and the positioning screw when the clamping length of the threaded connection pair to be measured is subsequently measured, thereby ensuring the accuracy and reliability of the measurement results; on the other hand, it is ensured that the clamping length of the threaded connection pair finally measured is the distance from the supporting surface of the bolt used in the threaded connection pair to the first tooth of the nut, thereby improving the accuracy of the measurement results. Furthermore, the diameter of the smooth rod portion is less than or equal to the outer diameter of the external thread of the screw portion, so that when the positioning screw is screwed into a nut with a non-threaded section in the internal threaded hole (such as a countersunk nut), it is ensured that the end of the smooth rod portion facing the nut can abut against the end of the internal thread of the nut facing the smooth rod portion, thereby ensuring the accuracy of the measurement result and improving the applicability of the positioning screw to different types of connecting pair nuts, thereby improving the applicability of the clamping length measuring device. Moreover, the positioning screw is provided with an internal threaded blind hole at one end of the smooth rod portion away from the screw portion, which, on the one hand, is used to realize the threaded connection between the positioning screw and one end of the connecting screw; on the other hand, after one end of the connecting screw is screwed into the internal threaded blind hole to a certain extent (such as one end of the connecting screw extends into the internal threaded blind hole of the positioning screw and abuts against the bottom of the internal threaded blind hole), the connecting screw can be restricted from continuing to be screwed in, thereby limiting the relative position of the connecting screw and the positioning screw, avoiding measurement errors caused by changes in the relative positions of the connecting screw and the positioning screw when the clamping length of the threaded connection pair to be measured is subsequently measured, further ensuring the accuracy and reliability of the measurement results. The clamping length measuring device is provided with a connecting screw and a measuring mechanism, and when measuring the clamping length of the threaded connection pair to be measured, the connecting part and the connection pair nut are clamped on the connected part sleeved on the connecting screw to simulate the actual assembly of the threaded connection pair, thereby measuring a clamping length that is closer to the actual use of the threaded connection pair to be measured, further improving the accuracy of the measurement results. In addition, the connecting screw and the positioning screw are connected by threads, which not only facilitates the assembly between the two, but also ensures the stability of the connection between the two, avoids the measurement error caused by the loose connection between the two, and improves the measurement accuracy of the measuring device. The hollow connecting part of the measuring mechanism and the measuring structure arranged thereon can move relative to the connecting screw to measure the position of one end of the connecting screw inserted into the connecting part in the connecting part, so as to accurately obtain the clamping length of the threaded connection pair according to the change of the position of one end of the connecting screw inserted into the connecting part in the connecting part determined in different situations.The clamping length measuring device has the characteristics of simple structure, easy use, low production cost and difficulty, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic structural diagram of a positioning screw, a connecting screw and a measuring mechanism of a clamping length measuring device in an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the structure of a measuring mechanism in an embodiment of the present invention;

[0042] Figure 3 It is a schematic cross-sectional view of the connection between the connecting screw, the positioning screw and the standard nut in the embodiment of the present invention;

[0043] Figure 4 It is a schematic diagram of the cross-section structure of the connection between the connecting screw, the positioning screw and the connecting pair nut in the embodiment of the present invention;

[0044] Figure 5 A schematic diagram of a cross-section structure of a clamping length measuring device during a zeroing operation in an embodiment of the present invention;

[0045] Figure 6 A schematic diagram of a cross-section structure of a clamping length measuring device in an embodiment of the present invention when measuring a connected member;

[0046] Figure 7 A schematic diagram of a cross-section structure of a clamping length measuring device in an embodiment of the present invention when measuring a connected member;

[0047] Figure 8 A schematic diagram of the structure of the clamping length measuring device in the embodiment of the present invention when measuring a connected member;

[0048] Fig. 9 for Figure 8 The corresponding cutaway structure diagram;

[0049] Fig.10 A schematic diagram of the structure of the clamping length measuring device in the embodiment of the present invention when measuring a connected member;

[0050] Fig.11 for Fig.10 The corresponding cutaway structure diagram;

[0051] Fig.12 A schematic diagram of a flow chart of a clamping length measurement method according to an embodiment of the present invention;

[0052] Fig.13 A schematic diagram of a flow chart of a clamping length measurement method according to an embodiment of the present invention;

[0053] Fig.14The figure is a flow chart of a method for measuring clamping length in an embodiment of the present invention.

[0054] Reference numerals:

[0055] 1. Positioning screw; 11. Screw portion; 12. Bare rod portion; 2. Connecting screw; 3. Measuring mechanism; 31. Connecting portion; 311. First columnar portion; 311a. Accommodating hole; 312. Second columnar portion; 312a. Through hole; 32. Measuring structure; 33. Display structure; 4. Fixing nut; 5. Standard nut; 7. Connecting sub-nut; 8. Connected member. DETAILED DESCRIPTION

[0056] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0057] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0058] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0059] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0060] This embodiment provides a clamping length measuring device and method.

[0061] like Figure 1 , Figure 3 and Figure 4 As shown, a clamping length measuring device provided in an embodiment of the present invention is applied to measure the clamping length of a threaded connection pair to be measured. The threaded connection pair to be measured includes a connection pair nut 7. The clamping length measuring device includes:

[0062] The positioning screw 1 comprises a screw portion 11 and a polished rod portion 12 which are integrally formed and coaxially arranged. An external thread for matching with the internal thread of the connecting sub-nut 7 is provided on the outer wall of the screw portion 11. The diameter of the polished rod portion 12 is larger than the inner diameter of the external thread of the screw portion 11 and smaller than or equal to the outer diameter of the external thread of the screw portion 11. An internally threaded blind hole is provided at one end of the polished rod portion 12 away from the screw portion 11.

[0063] A connecting screw 2, wherein the first end of the connecting screw 2 is provided with an external thread matching the internal thread of the internal thread blind hole;

[0064] The measuring mechanism 3 includes a hollow connecting portion 31 and a measuring structure 32 arranged on the connecting portion 31. The measuring structure 32 is used to monitor the position of the second end of the connecting screw 2 in the connecting portion 31 when the connecting portion 31 is sleeved on the connecting screw 2, so as to display the clamping length of the threaded connection pair to be measured based on the position.

[0065] The clamping length measuring device is used to measure the clamping length (e.g. Figure 6 , Figure 7 , Fig. 9 and Fig.11 The clamping length L in the threaded connection pair is as follows. The threaded connection pair to be measured includes a connected part 8, a bolt for clamping or tightening the connected part 8 (or other fasteners that can be threadedly connected with the connection pair nut 7 to clamp or tighten the connected part 8) and the connection pair nut 7; the clamping length measuring device includes a positioning screw 1, a connecting screw 2 and a measuring mechanism 3. The clamping length of the threaded connection pair is the distance from the supporting surface of the bolt used in the threaded connection pair (or the end surface of the connected part 8 of the threaded connection pair away from the end of the connection pair nut 7) to the first thread of the nut (or the end point of the internal thread of the nut facing the end of the connected part 8).

[0066] Specifically, the positioning screw 1 has a screw portion 11 and a polished rod portion 12 that are integrally formed and coaxially arranged to improve the overall structural strength of the positioning screw 1. The screw portion 11 and the polished rod portion 12 are both cylindrical, and the outer wall of the screw portion 11 is provided with an external thread that matches the internal thread of the connection pair nut 7 of the threaded connection pair to be measured, so as to achieve the threaded connection between the screw portion 11 and the connection pair nut 7, improve the stability of the connection between the screw portion 11 and the connection pair nut 7, and avoid errors in the measurement of the clamping length of the threaded connection pair to be measured due to the loose connection between the screw portion 11 and the connection pair nut 7. The diameter of the smooth rod portion 12 is designed to be larger than the inner diameter of the external thread of the screw rod portion 11, so that when the positioning screw rod 1 is threadedly connected with the internal thread of the corresponding nut (such as the connecting auxiliary nut 7) through the external thread of the screw rod portion 11, the smooth rod portion 12 can limit the threaded connection between the screw rod portion 11 and the nut. That is to say, when the screw rod portion 11 is screwed into the nut, the external thread of the screw rod portion 11 cooperates with the internal thread of the nut until the end of the internal thread of the nut facing the smooth rod portion 12 abuts against the end of the smooth rod portion 12 facing the nut (at this time, the positioning screw 1 is said to be completely screwed into the nut; if Figure 3 , Figure 4 As shown in the figure, since the diameter of the polished rod portion 12 is larger than the inner diameter of the external thread of the screw portion 11, the polished rod portion 12 cannot be screwed into the corresponding nut, thereby limiting the relative position of the positioning screw 1 and the corresponding nut (i.e., limiting the positioning screw 1 to continue to be screwed into the corresponding nut, and having no limit effect on the positioning screw 1 being screwed out of the corresponding nut in the opposite direction); and the diameter of the polished rod portion 12 is less than or equal to the outer diameter of the external thread of the screw portion 11, so that when the positioning screw 1 is screwed into the nut with no thread section in the internal thread hole (such as Figure 4 As shown, Figure 4When the connection pair nut 7 in the embodiment is a countersunk nut with a non-threaded section in the internal threaded hole, it is ensured that the positioning screw 1 can be completely screwed into the nut, that is, it is ensured that the end of the polished rod 12 facing the nut can abut against the end of the internal thread of the nut facing the polished rod 12, so as to avoid the situation that the end of the polished rod 12 facing the nut interferes with the non-threaded section of the internal threaded hole of the nut due to the diameter of the polished rod 12 being larger than the outer diameter of the external thread, thereby causing the end of the polished rod 12 facing the nut to be unable to abut against the end of the internal thread of the nut facing the polished rod 12. In this way, it is ensured that the positioning screw 1 can be completely screwed into different types of connection pair nuts 7, thereby ensuring that the clamping length measuring device can accurately measure the clamping length of the threaded connection pair to be measured. In addition, the positioning screw 1 is provided with an internally threaded blind hole (i.e., a blind hole with an internal thread on the hole wall) at one end of the smooth rod portion 12 away from the screw portion 11, and the internally threaded blind hole can be provided in the smooth rod portion 12, or penetrate the smooth rod portion 12 and extend into the screw portion 11; the connecting screw 2 is a columnar rod body (such as a cylindrical rod body), and it is provided with an external thread on the outer wall at least at one end for connecting with the positioning screw 1 (the end of the connecting screw 2 for connecting with the positioning screw 1 is recorded as the first end of the connecting screw 2, and the other end is recorded as the second end), and the external thread at the first end of the connecting screw 2 is adapted to the internal thread of the internally threaded blind hole of the positioning screw 1, so that the first end of the connecting screw 2 can be threadedly connected with the positioning screw 1 at the internally threaded blind hole. In some embodiments, the external thread on the outer wall of the connecting screw 2 extends from the first end to the second end, so that the connecting screw 2 can be threadedly connected with the positioning screw 1 through either end, thereby improving the convenience of using the clamping length measuring device. The measuring mechanism 3 includes a hollow connecting portion 31 and a measuring structure 32 arranged thereon. When the connecting screw 2 is threadedly connected to the positioning screw 1 through the first end, the connecting portion 31 can be sleeved on the connecting screw 2 by the second end of the connecting screw 2. The measuring structure 32 is used to measure the position of the second end of the connecting screw 2 inserted into the connecting portion 31 in the connecting portion 31, and based on the position (through the measuring mechanism 3), the clamping length of the threaded connection pair to be measured is displayed. Exemplarily, the measuring mechanism 3 can be provided with a display structure 33 that is communicatively connected to the measuring structure 32 to display the clamping length of the threaded connection pair to be measured, so that the user can intuitively, clearly and promptly understand the clamping length of the threaded connection pair to be measured; wherein the display structure 33 can be provided on the connecting portion 31, or separately provided from the connecting portion 31.

[0067] When the clamping length measuring device is used to measure the clamping length of the threaded connection pair to be measured, the positioning screw 1 is completely screwed into the connection pair nut 7; one end (i.e., the first end) of the connecting screw 2 is screwed into the internal thread blind hole of the positioning screw 1 to achieve the threaded connection between the connecting screw 2 and the positioning screw 1; the connected member 8 is sleeved on the connecting screw 2 through its hole for accommodating the bolt, and the measuring mechanism 3 is sleeved on the connecting screw 2 from one end (i.e., the second end) of the connecting screw 2 away from the positioning screw 1 through the connecting portion 31. The connected member 8 is clamped by the connecting portion 31 and the connection pair nut 7, and the end of the connecting portion 31 facing the connected member 8 is equivalent to the supporting surface of the bolt of the threaded connection pair, and the whole formed by the connecting portion 31 and the connecting screw 2 is equivalent to the bolt of the threaded connection pair, so as to simulate the real assembly of the threaded connection pair and improve the accuracy of the clamping length measurement of the threaded connection pair. Among them, the measuring structure 32 of the measuring mechanism 3 is used to measure the position of one end of the connecting screw 2 extending into the connecting part 31 in the connecting part 31. According to the change of the position of one end of the connecting screw 2 extending into the connecting part 31 in the connecting part 31 determined in different situations, the clamping length of the threaded connection pair can be obtained.

[0068] For example, if the connecting nut 7 is a standard nut (such as Figure 2 The standard nut 5) is a nut whose end faces at both ends of its own axis are perpendicular to its own axis and whose ends of the internal thread are flush with the end faces of the standard nut at both ends of its own axis; after the positioning screw 1 is completely screwed into the standard nut, the end of the smooth rod portion 12 of the positioning screw 1 facing the screw portion 11 abuts (or fits) with the end face of the standard nut facing the smooth rod portion 12, and the connecting screw 2 is threadedly connected to the positioning screw 1 (such as Figure 3 , Figure 4 As shown, the first end of the connecting screw 2 extends into the internal thread blind hole of the positioning screw 1 and abuts against the bottom of the internal thread blind hole). When the connected member 8 is not provided on the connecting screw 2, the connecting portion 31 is sleeved on the connecting screw 2 and the end of the connecting portion 31 facing the standard nut abuts against the supporting surface of the standard nut (as shown in FIG. Figure 5As shown), at this time, the position of the second end of the connecting screw 2 extending into the connecting part 31 in the connecting part 31 (recorded as the first position) can be measured by the measuring structure 32; when the connected part 8 is set on the connecting screw 2, the connecting part 31 is sleeved on the connecting screw 2 and the end of the connecting part 31 facing the standard nut is clamped with the standard nut for clamping the connected part 8 (at this time, the end of the connecting part 31 facing the standard nut is in contact with the end of the connected part 8 facing the connecting part 31, and the end of the standard nut facing the connected part 8 is in contact with the end of the connected part 8 facing the standard nut), and the position of the end of the connecting screw 2 extending into the connecting part 31 in the connecting part 31 (recorded as the second position) is measured by the measuring structure 32; in this way, the distance between the first position and the second position on the axis of the connecting part 31 is the clamping length of the connected part 8. If the connection pair nut 7 is a countersunk nut, and in the threaded connection pair where the countersunk nut is located, the unthreaded section of the internal threaded hole of the countersunk nut is located at the end of its internal threaded hole facing the connected member 8; after the positioning screw 1 is completely screwed into the countersunk nut from the unthreaded section, the end of the smooth rod portion 12 of the positioning screw 1 facing the screw portion 11 abuts against the end of the internal thread of the countersunk nut facing the smooth rod portion 12, and the connecting screw 2 is threadedly connected to the positioning screw 1 (for example, one end of the connecting screw 2 extends into the internal threaded blind hole of the positioning screw 1 and abuts against the bottom of the internal threaded blind hole). When the connected member 8 is set on the connecting screw 2, the connecting portion 3 is 1 is sleeved on the connecting screw 2 and makes the end of the connecting portion 31 facing the countersunk nut clamp the connected member 8 with the countersunk nut (at this time, the end of the connecting portion 31 facing the standard nut abuts against the end of the connected member 8 facing the connecting portion 31, and the end of the countersunk nut facing the connected member 8 abuts against the end of the connected member 8 facing the connecting secondary nut 7), and the position of the end of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31 at this time is measured by the measuring structure 32 (recorded as the second position); in this way, the distance between the second position and the above-mentioned first position on the axis of the connecting portion 31 is the clamping length of the connected member 8. In some embodiments, based on the threaded connection between the connecting screw 2 and the positioning screw 1 (such as one end of the connecting screw 2 extends into the internal threaded blind hole of the positioning screw 1 and abuts against the bottom of the internal threaded blind hole), one end of the connecting screw 2 away from the positioning screw 1 extends into the connecting part 31 along the axis of the connecting part 31 until the end surface of the connecting part 31 facing one end of the positioning screw 1 is flush with the end surface of the bare rod portion 12 of the positioning screw 1 facing one end of the screw portion 11. At this time, the position of the end of the connecting screw 2 extending into the connecting part 31 in the connecting part 31 is the first position; the first position can be obtained by a standard nut or other similar structures.

[0069] In this optional embodiment, the clamping length measuring device is provided with a positioning screw 1 including an integrally formed and coaxially arranged screw portion 11 and a smooth rod portion 12, and the diameter of the smooth rod portion 12 is larger than the inner diameter of the external thread of the screw portion 11, so that the positioning screw 1 can limit the screw portion 11 by the smooth rod portion 12 when it is screwed into the connecting nut 7, ensuring that when the positioning screw 1 is fully screwed into the connecting nut 7, the smooth rod portion 12 can abut against the end of the internal thread of the connecting nut 7. On the one hand, the relative position of the connecting nut 7 and the positioning screw 1 is limited, avoiding measurement errors caused by changes in the relative positions of the connecting screw 2 and the positioning screw 1 when the clamping length of the threaded connection to be measured is subsequently measured, thereby ensuring the accuracy and reliability of the measurement results; on the other hand, it ensures that the clamping length of the threaded connection finally measured is the distance from the supporting surface of the bolt used in the threaded connection to the first tooth of the nut, thereby improving the accuracy of the measurement results. And the diameter of the smooth rod portion 12 is less than or equal to the outer diameter of the external thread of the screw portion 11, so that when the positioning screw 1 is screwed into a nut with a non-threaded section in the internal threaded hole (such as a countersunk nut), it is ensured that the end of the smooth rod portion 12 facing the nut can abut against the end of the internal thread of the nut facing the smooth rod portion 12, thereby ensuring the accuracy of the measurement result, and improving the applicability of the positioning screw 1 to different types of connecting pair nuts 7, and improving the applicability of the clamping length measuring device. Moreover, the positioning screw 1 is provided with an internally threaded blind hole at the end of the smooth rod portion 12 away from the screw portion 11. On the one hand, it is used to realize the threaded connection between the positioning screw 1 and one end of the connecting screw 2; on the other hand, after one end of the connecting screw 2 is screwed into the internally threaded blind hole to a certain extent (such as one end of the connecting screw 2 extends into the internally threaded blind hole of the positioning screw 1 and abuts against the bottom of the internally threaded blind hole), the connecting screw 2 can be restricted from continuing to be screwed in, thereby limiting the relative position of the connecting screw 2 and the positioning screw 1, avoiding measurement errors caused by changes in the relative positions of the connecting screw 2 and the positioning screw 1 when the clamping length of the threaded connection pair to be measured is measured later, and further ensuring the accuracy and reliability of the measurement results. The clamping length measuring device is provided with a connecting screw 2 and a measuring mechanism 3. When measuring the clamping length of the threaded connection pair to be measured, the connecting part 31 and the connecting pair nut 7 clamp the connected member 8 sleeved on the connecting screw 2 to simulate the actual assembly of the threaded connection pair, thereby measuring a clamping length that is closer to the actual use of the threaded connection pair to be measured, further improving the accuracy of the measurement result. In addition, the connecting screw 2 and the positioning screw 1 are connected by threads, which not only facilitates the assembly between the two, but also ensures the stability of the connection between the two, avoids the measurement error caused by the loose connection between the two, and improves the measurement accuracy of the measuring device.The hollow connection part 31 of the measuring mechanism 3 and the measuring structure 32 arranged thereon can move relative to the connecting screw 2 so as to measure the position of one end of the connecting screw 2 inserted into the connecting part 31 in the connecting part 31, thereby accurately obtaining the clamping length of the threaded connection pair according to the change of the position of one end of the connecting screw 2 inserted into the connecting part 31 in the connecting part 31 determined in different situations. The clamping length measuring device has the characteristics of simple structure, convenient use, low production cost and difficulty, etc.

[0070] In addition, the clamping length measuring device in this embodiment can simulate the actual assembly of the threaded connection pair. Therefore, there is no need to consider the problems that the irregularity of the connected part 8 affects the accuracy of the measurement result, the interference between the vernier caliper and the connected part 8, and the inaccurate measurement of the chamfer or countersink of the nut by the vernier caliper when measuring with a vernier caliper. The distance from the supporting surface of the bolt used in the threaded connection pair (or the end face of the connected part 8 of the threaded connection pair away from the end of the connection pair nut 7) to the first tooth of the nut (or the end point of the internal thread of the nut facing the connected part 8) can be accurately measured, that is, the clamping length of the threaded connection pair can be accurately measured, thereby improving the accuracy of the clamping length measurement of the threaded connection pair to be measured.

[0071] Optionally, the axial lengths of the screw portion 11 and the smooth rod portion 12 of the positioning screw 1 can be determined according to requirements. In some embodiments, the axial length of the positioning screw 1 (i.e., the length of the positioning screw 1 in the direction of its own axis) is d, the axial length of the screw portion 11 (i.e., the length of the screw portion 11 in the direction of the axis of the positioning screw 1) is 0.8d, and the axial length of the smooth rod portion 12 (i.e., the length of the smooth rod portion 12 in the direction of the axis of the positioning screw 1) is 0.2d. In some embodiments, the axial length of the positioning screw 1 is equal to the outer diameter of the external thread of the screw portion 11.

[0072] Optionally, after the positioning screw 1 is completely screwed into the connection pair nut 7, a certain fitting torque is applied to ensure the stability of the connection between the positioning screw 1 and the connection pair nut 7; after one end of the connecting screw 2 is screwed into the internal thread blind hole of the positioning screw 1, a certain fitting torque is applied to ensure the stability of the connection between the positioning screw 1 and the connecting screw 2. In this way, when the clamping length of the threaded connection pair to be measured is subsequently measured, the measurement error caused by the change in the relative position between the connecting screw 2, the positioning screw 1 and the connecting screw 2 is avoided, and the accuracy and reliability of the measurement result are ensured.

[0073] Optionally, in order to avoid affecting the threaded connection between the positioning screw 1 and the connecting nut 7 when one end of the connecting screw 2 is screwed into the positioning screw 1, the external thread of the connecting screw 2 and the external thread of the screw portion 11 of the positioning screw 1 have the same rotation direction, such as both are left-handed threads, or both are right-handed threads.

[0074] Alternatively, if Figure 8-Figure 11As shown, the clamping length measuring device also includes a fixing nut 4, the internal thread of the fixing nut 4 is adapted to the external thread of the connecting screw 2, and the end faces of the fixing nut 4 at both ends of its own axis are perpendicular to its own axis.

[0075] Specifically, in addition to the positioning screw 1, the connecting device and the measuring mechanism 3, the threaded connection pair clamping length also includes a fixing nut 4, the internal thread of the fixing nut 4 matches the external thread of the connecting screw 2, the connecting screw 2 can be screwed into the fixing nut 4, and the position of the fixing nut 4 on the connecting screw 2 can be adjusted as needed, so as to achieve stable clamping of the connected part 8 by the fixing nut 4 and the connecting pair nut 7. In this way, on the one hand, the stability of the relative position of the connected part 8 and the connecting screw 2 is ensured, thereby avoiding errors caused by changes in the relative position of the connected part 8 and the connecting screw 2 during the measurement process; on the other hand, for the connected part 8 including multiple sub-components, when the multiple sub-components are not tightly fitted, there will be gaps or clearances (or called gaps) between each other. In the threaded connection pair, when the multiple sub-components are connected by bolts and the connection pair nuts 7, the gaps or clearances existing therebetween will be eliminated by the tightening torque. Therefore, by setting the fixing nut 4 and when the connected part 8 is set on the connecting screw 2 between the fixing nut 4 and the positioning screw 1, by tightening the fixing nut 4 (such as applying the necessary fitting torque to the fixing nut 4) to eliminate the corresponding gaps or clearances of the connected part 8, it can be ensured that the clamping length of the threaded connection pair to be measured that is finally measured is true and accurate. In other words, the setting of the fixing nut 4 can further improve the accuracy of the measurement result of the clamping length measuring device for the clamping length of the threaded connection pair to be measured.

[0076] The two end faces of the fixing nut 4 are perpendicular to its axis, and can provide a flat contact surface for contacting the end of the connected member 8 away from the connecting nut 7, and provide a flat contact surface for contacting the end of the connecting portion 31 toward the connecting nut 7, so as to ensure that the fixing nut 4 can stably contact the connected member 8 and the connecting portion 31, avoid measurement errors caused by uneven contact surfaces, and avoid measurement errors caused by the two end faces of the fixing nut 4 not being perpendicular to its axis, and ensure that the distance between the connected member 8 contacting one end of the fixing nut 4 and the connecting portion 31 contacting the other end of the fixing nut 4 is The distance between the connected part 8 and the fixing nut 4 is a constant value (i.e., the thickness of the fixing nut 4, which is also the length of the fixing nut 4 on its axis) to ensure the accuracy of the measurement result of the clamping length measuring device. For example, when the two end faces of the fixing nut 4 are not perpendicular to its axis, the contact position between the fixing nut 4 and the connected part 8 will change as the fixing nut 4 or the fixing nut 4 rotates around the axis of the connecting screw 2, thereby causing the distance between the connected part 8 in contact with one end of the fixing nut 4 and the connecting part 31 in contact with the other end of the fixing nut 4 to change (e.g., be greater than the thickness of the fixing nut 4), resulting in an inaccurate measurement result ultimately obtained based on the thickness of the fixing nut 4.

[0077] In this optional embodiment, the internal thread of the fixing nut 4 is matched with the external thread of the connecting screw 2, so that the fixing nut 4 and the connecting screw 2 form a tight threaded connection. On the one hand, the firmness of the connection is ensured, and the fixing nut 4 and the connecting pair nut 7 form a stable clamping of the connected member 8, thereby avoiding errors caused by loose connection during the measurement process; on the other hand, while ensuring that the fixing nut 4 and the connecting pair nut 7 form a stable clamping of the connected member 8, the gap (or gap) of the connected member 8 with a gap (or gap) is eliminated, simulating the actual assembly of the threaded connection pair, thereby measuring a clamping length that is closer to the actual use of the threaded connection pair to be measured, and further improving the accuracy of the measurement result. Moreover, by setting the fixing nut 4, the clamping length measuring device can better cope with the situation where there is a gap in the connected member 8, expanding the application range of the clamping length measuring device and improving the practicality of the clamping length measuring device. In addition, the fixing nut 4 has the characteristics of simple structure, low manufacturing difficulty and cost, and makes the clamping length measuring device easy to use, that is, the user can quickly and conveniently install and disassemble the clamping length measuring device.

[0078] Alternatively, if Figure 1 As shown, the connecting portion 31 includes a first columnar portion 311, and the first columnar portion 311 is provided with an accommodating hole 311a for accommodating the connecting screw 2;

[0079] or, as Figure 2As shown, the connecting portion 31 includes a first columnar portion 311 and a second columnar portion 312 that are integrally formed and coaxially arranged, the first columnar portion 311 is provided with a receiving hole 311a, and the second columnar portion 312 is provided with a through hole 312a connected to the receiving hole 311a, the connected receiving hole 311a and through hole 312a are used to accommodate the connecting screw 2, and the diameter of the through hole 312a is greater than or equal to the diameter of the light rod portion 12, and the axial length of the second columnar portion 312 is greater than or equal to the axial length of the light rod portion 12.

[0080] Specifically, Figure 1 As shown, when a clamping length measuring device is used to measure the clamping length of the threaded connection pair to be measured, if the above-mentioned first position is known, then in the subsequent measurement process, the connecting portion 31, the connecting portion 31 needs to abut against the connected member 8 or the fixing nut 4, without considering the interference between the light rod portion 12 and the connecting portion 31. In this case, the connecting portion 31 of the measuring mechanism 3 used includes a first columnar portion 311, and the first columnar portion 311 is provided with a receiving hole 311a for accommodating the connecting screw 2. The first columnar portion 311 can be sleeved on the connecting screw 2 through the receiving hole 311a, so as to clamp the connected member 8 with the connecting pair nut 7 when measuring the connected member 8, or to clamp the connected member 8 through the fixing nut 4 and the connecting pair nut 7 when measuring the connected member 8, so as to ensure the accuracy of the measurement result. In some embodiments, the first columnar portion 311 can be a columnar structure such as a cylindrical structure or a prismatic structure.

[0081] Or, if Figure 2As shown, when the clamping length measuring device is used to measure the clamping length of the threaded connection pair to be measured, if the above-mentioned first position is unknown, the connecting portion 31 needs to abut against the connection pair nut 7 in the subsequent measurement process, and the interference between the light rod portion 12 and the connecting portion 31 needs to be considered. In this case, the connecting portion 31 of the measuring mechanism 3 used includes a first columnar portion 311 and a second columnar portion 312 arranged coaxially, the second columnar portion 312 is provided with a through hole 312a for accommodating the connecting screw 2, and the first columnar portion 311 is provided with a receiving hole 311a for accommodating the connecting screw 2, and the receiving hole 311a and the through hole 31 2a are coaxially arranged and connected, so that the connected accommodation hole 311a and through hole 312a can be used to accommodate the connecting screw 2, that is, the second end of the connecting screw 2 can pass through the through hole 312a and the accommodation hole 311a, and move in the first columnar part 311 and the second columnar part 312 along the axial direction of the first columnar part 311 and the second columnar part 312, so that it is convenient for the second columnar part 312 and the connecting sub-nut 7 to clamp the connected part 8 when measuring the connected part 8, or the second columnar part 312 forms a clamp on the connected part 8 through the fixing nut 4 and the connecting sub-nut 7 when measuring the connected part 8, so as to ensure the accuracy of the measurement result. The first columnar part 311 and the second columnar part 312 are integrally formed to improve the overall structural strength of the connecting part 31. The diameter of the through hole 312a is greater than or equal to the diameter of the light rod 12, and the axial length of the second columnar portion 312 is greater than or equal to the axial length of the light rod 12, so as to ensure that the connection portion 31 can accommodate the light rod 12 through the through hole 312a, thereby ensuring that the end face of the second columnar portion 312 of the connection portion 31 facing the connection pair nut 7 can smoothly abut (or fit) with the end face of the connection pair nut 7 facing the connection screw 2 during the measurement process, so as to ensure the accuracy of the measurement result, and avoid the situation where the second columnar portion 312 cannot abut against the connection pair nut 7 due to the diameter of the through hole 312a being smaller than the diameter of the light rod 12 or the axial length of the second columnar portion 312 being smaller than the axial length of the light rod 12, thereby causing measurement errors. It is worth noting that the connection portion 31 including the first columnar portion 311 and the second columnar portion 312 is also suitable for measuring the clamping length of the threaded connection pair to be measured when the above-mentioned first position is known.

[0082] Alternatively, if Figure 2 , Figure 6-Figure 11 As shown, the cross-sectional area of ​​the second columnar portion 312 is greater than the cross-sectional area of ​​the first columnar portion 311 .

[0083] In this optional embodiment, the cross-sectional area of ​​the first columnar portion 311 is smaller than the cross-sectional area of ​​the second columnar portion 312 , so that the connecting portion 31 is more compact in structure, thereby facilitating reducing the manufacturing cost of the connecting portion 31 .

[0084] Alternatively, if Figure 1As shown, the outer side wall of the connecting screw rod 2 is provided with an external thread, and the external thread of the connecting screw rod 2 extends from the first end to the second end of the connecting screw rod 2;

[0085] The accommodating hole 311a is a cylindrical hole, and the diameter of the cylindrical hole is greater than or equal to the outer diameter of the external thread of the connecting screw 2; or, the accommodating hole 311a is a cylindrical hole, and the hole wall of the cylindrical hole is provided with an internal thread for matching with the external thread of the connecting screw 2.

[0086] Specifically, the outer wall of the connecting screw 2 is provided with an external thread, and the external thread of the connecting screw 2 extends from the first end of the connecting screw 2 to the second end (such as Figure 1 As shown), the connecting screw 2 can be threadedly connected to the positioning screw 1 through either end, thereby improving the convenience of using the clamping length measuring device.

[0087] The accommodating hole 311a of the first columnar portion 311 can be a cylindrical hole with a smooth inner wall, and the diameter of the cylindrical hole is greater than or equal to the outer diameter of the external thread of the connecting screw 2, so as to accommodate the connecting screw 2, so that the connecting screw 2 and the connecting portion 31 can be easily installed and disassembled, simplifying the measurement process using the clamping length measuring device. The accommodating hole 311a of the first columnar portion 311 can also be a cylindrical hole with an internal thread on the hole wall that is compatible with the external thread of the connecting screw 2. The accommodating hole 311a is threadedly connected to the connecting screw 2 through the internal thread to ensure the stability of the connection between the connecting screw 2 and the connecting portion 31 during the measurement process. On the one hand, the threaded connection ensures a reliable connection between the connecting screw 2 and the connecting portion 31, prevents loosening during the measurement process, and avoids the situation where the connection between the connecting screw 2 and the connecting portion 31 is not stable. The measurement error is easily generated; on the other hand, the threaded connection ensures that the connection between the connecting screw 2 and the connecting portion 31 is stable at any connection position, and a certain fitting torque can be applied to the first columnar portion 31, so that when measuring the connected part 8, the connecting part 31 and the connecting sub-nut 7 can form a stable clamp on the connected part 8, or when measuring the connected part 8, the connecting part 31 clamps the connected part 8 through the fixing nut 4 and the connecting sub-nut 7, thereby ensuring the accuracy of the measurement result.

[0088] In this optional embodiment, the first cylindrical portion 311 having a cylindrical hole with a smooth inner wall, or the first cylindrical portion 311 having a cylindrical hole with an internal thread, can ensure that the connection portion 31 and the connecting screw 2 can be easily installed and disassembled, simplifying the measurement process using the clamping length measuring device. Among them, the first cylindrical portion 311 having a cylindrical hole with a smooth inner wall can further improve the convenience of connecting or separating the connection portion 31 and the connecting screw 2, and further simplify the measurement process using the clamping length measuring device; the first cylindrical portion 311 having a cylindrical hole with an internal thread can ensure the stability when the connecting screw 2 is connected to the connection portion 31, and the threaded connection screw 2 and the connection portion 31 are as a whole, equivalent to the bolt of the threaded connection pair to be measured, that is, the clamping length measuring device can further truly simulate the actual assembly of the threaded connection pair, so as to measure the clamping length that is closer to the actual use of the threaded connection pair to be measured, and further improve the accuracy of the measurement result.

[0089] Alternatively, if Figure 3 As shown, the clamping length measuring device also includes a standard nut 5, the internal thread of the standard nut 5 is adapted to the external thread of the screw portion 11, the end faces of the standard nut 5 at both ends of its own axis are perpendicular to its own axis, and the two ends of the internal thread of the standard nut 5 are respectively flush with the end faces of the standard nut 5 at both ends of its own axis.

[0090] Specifically, the clamping length measuring device also includes a standard nut 5. The internal thread of the standard nut 5 is adapted to the external thread of the screw portion 11 of the positioning screw 1, so that the positioning screw 1 can be screwed into the standard nut 5 through the screw portion 11, thereby realizing a threaded connection between the standard nut 5 and the positioning screw 1. The two end faces of the standard nut 5 are perpendicular to its own axis, ensuring that the standard nut 5 can provide a flat contact surface when connected to the positioning screw 1, thereby avoiding measurement errors caused by uneven contact surfaces. The two ends of the internal thread of the standard nut 5 are respectively flush with the end faces of the standard nut 5 located at both ends of its own axis, so that the screw portion 11 of the positioning screw 1 can be screwed into the standard nut 5 from any end of the standard nut 5 until the end of the smooth rod portion 12 of the positioning screw 1 facing the nut can abut against the end of the internal thread of the nut facing the smooth rod portion 12. Figure 3As shown, at this time, the positioning screw 1 is completely screwed into the nut, and the end of the smooth rod 12 of the positioning screw 1 facing the nut is simultaneously abutted (or fitted, flush) with the end face of the nut facing the smooth rod 12, so as to facilitate the determination of the above-mentioned first position by the standard nut 5. That is to say, during the measurement process, the positioning screw 1 can be completely screwed into the standard nut 5, and the connecting screw 2 can be connected to the positioning screw 1 (such as one end of the connecting screw 2 is inserted into the internal threaded blind hole of the positioning screw 1 and abutted with the bottom of the internal threaded blind hole). At this time, the end face of the standard nut 5 facing the smooth rod 12 is used as a reference surface to determine the end face of the smooth rod 12 facing the standard nut 5 (this end face is small and difficult to measure), and the connecting part 31 is sleeved on the connecting screw 2 and the connecting part 31 is abutted (or fitted) with the reference surface. At this time, the position of the end of the connecting screw 2 extending into the connecting part 31 in the connecting part 31 is the first position.

[0091] In this optional embodiment, the threaded connection between the standard nut 5 and the positioning screw 1 allows the standard nut 5 and the positioning screw 1 to be easily installed and removed, simplifying the measurement process. The threaded connection ensures a reliable connection between the standard nut 5 and the positioning screw 1, preventing loosening during the measurement process and causing measurement errors.

[0092] Optionally, the measuring structure 32 includes a distance measuring structure 32, and the distance measuring structure 32 is used to measure the distance between one end of the connecting screw 2 extending into the connecting portion 31 and a fixed reference point on the connecting portion 31 on the axis of the connecting portion 31;

[0093] Alternatively, the measuring structure 32 includes a displacement measuring structure 32 , and the displacement measuring structure 32 is used to measure the length of the connecting screw 2 extending into the connecting portion 31 along the axis of the connecting portion 31 .

[0094] In this optional embodiment, the monitoring of the position of one end of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31 by the measuring structure 32 can be achieved by a distance measuring structure 32 for measuring the distance between the one end of the connecting screw 2 extending into the connecting portion 31 and a fixed reference point set on the connecting portion 31 (or selected on the connecting portion 31) on the axis of the connecting portion 31, or by a displacement measuring structure 32 for measuring the length of the connecting screw 2 extending into the connecting portion 31 along the axis of the connecting portion 31. The fixed reference point is a fixed position on the connecting portion 31, and the position of the one end of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31 can be reflected by determining the distance between the one end of the connecting screw 2 extending into the connecting portion 31 and the position point. In some embodiments, the distance measuring structure 32 includes a distance sensor, and the displacement measuring structure 32 includes a displacement sensor.

[0095] Exemplarily, for the distance measuring structure 32, if the fixed reference point is set on the end surface of the connecting part 31 facing the connecting sub-nut 7, then the distance between the end of the connecting screw 2 extending into the connecting part 31 and the fixed reference point of the connecting part 31 on the axis of the connecting part 31 measured by the distance measuring structure 32 is the length of the connecting screw 2 extending into the connecting part 31; if the accommodating hole 311a of the connecting part 31 is a blind hole, and the fixed reference point is set at the bottom of the blind hole, then the distance between the end of the connecting screw 2 extending into the connecting part 31 and the fixed reference point of the connecting part 31 on the axis of the connecting part 31 measured by the distance measuring structure 32 is the distance between the end of the connecting screw 2 extending into the connecting part 31 and the bottom of the blind hole on the axis of the connecting part 31, and the length of the blind hole on the axis of the connecting part 31 minus this distance can be obtained. The length of the connecting screw 2 extending into the connecting part 31. The displacement measuring structure 32 can measure the length of the connecting screw 2 extending into the connecting part 31 along the axis of the connecting part 31 , that is, measure the distance between one end of the connecting screw 2 extending into the connecting part 31 and the fixed reference point of the connecting part 31 on the axis of the connecting part 31 .

[0096] like Figure 6 , Figure 7 and Fig.12 As shown, an embodiment of the present invention provides a clamping length measurement method, based on the above-mentioned clamping length measurement device, the clamping length measurement method includes the following steps:

[0097] Step 100: Select a positioning screw 1 that matches the connection pair nut 7 of the threaded connection pair to be measured.

[0098] Specifically, when using a clamping length measuring device to measure the clamping length of the threaded connection pair to be measured, first through step 100, select the positioning screw 1 of the clamping length measuring device that is compatible with the connection pair nut 7 of the threaded connection pair to be measured, so that the external thread of the screw portion 11 of the positioning screw 1 is compatible with the internal thread of the connection pair nut 7, ensuring that in the subsequent steps, the positioning screw 1 can be threadedly connected with the connection pair nut 7 smoothly and stably through the screw portion 11.

[0099] Step 300 , screw the positioning screw 1 completely into the connecting pair nut 7 .

[0100] Specifically, the positioning screw 1 is completely screwed into the connecting nut 7, wherein completely screwed in means that when the positioning screw 1 is screwed into the connecting nut 7 through the screw portion 11, the external thread of the screw portion 11 cooperates with the internal thread of the nut until the end of the internal thread of the connecting nut 7 facing the polished rod portion 12 abuts against the end of the polished rod portion 12 facing the nut. In this way, the polished rod portion 12 cannot be screwed into the internal thread of the connecting nut 7, and the polished rod portion 12 limits the positioning screw 1 from continuing to be screwed into the connecting nut 7, thereby ensuring the stability of the relative position between the positioning screw 1 and the connecting nut 7, avoiding the measurement error caused by the change in the relative position between the positioning screw 1 and the connecting nut 7 when the clamping length of the threaded connection pair to be measured is measured later, and ensuring the accuracy and reliability of the measurement results.

[0101] Step 400 , connecting the first end of the positioning screw 1 and the connecting screw 2 .

[0102] Specifically, the first end of the connecting screw 2 having an external thread that matches the internal thread of the internal thread blind hole of the positioning screw 1 is threadedly connected to the positioning screw 1 at the internal thread blind hole of the positioning screw 1. As for the connection between the positioning screw 1 and the connecting screw 2, illustratively, the first end of the connecting screw 2 extends into the internal thread blind hole of the positioning screw 1 and abuts against the bottom of the internal thread blind hole, thereby ensuring the stability of the connection and relative position between the connecting screw 2 and the positioning screw 1 and avoiding measurement errors caused by unstable connection.

[0103] In some embodiments, for different specifications of the connecting pair nuts 7, the specifications of the selected positioning screw 1 are also different, and it is necessary to ensure that the positioning screw 1 can smoothly and stably realize threaded connection with the connecting pair nut 7. For different specifications of positioning screws 1, the specifications of the internal threaded blind holes of different positioning screws 1 can be different to match the connecting screws 2 of different specifications; the specifications of the internal threaded blind holes of different positioning screws 1 can also be the same to match the same connecting screw 2 (or the same specification of connecting screw 2), and because the measuring mechanism 3 is generally compatible with the connecting screw 2, therefore, if the specifications of the internal threaded blind holes of the positioning screws 1 of the clamping length measuring device that are used to match the connecting pair nuts 7 of different specifications are the same, the clamping length measuring device can use the same or the same specification of connecting screw 2 when using different positioning screws 1, which can reduce the cost and difficulty of using the clamping length measuring device.

[0104] Step 500 : sleeve the connected member 8 of the threaded connection pair to be measured onto the connecting screw 2 .

[0105] Specifically, the connected part 8 is sleeved onto the connecting screw 2 from the end of the connecting screw 2 away from the connecting pair nut 7 through the hole of the connected part 8 for installing the bolt, so that the measuring mechanism 3 and the connecting pair nut 7 can clamp the connected part 8 during the subsequent measurement process, thereby simulating the actual assembly condition of the threaded connection pair to be measured and improving the accuracy of the measurement results.

[0106] Step 700, the measuring mechanism 3 after the zeroing operation is sleeved on the connecting screw 2 from the second end of the connecting screw 2, and the connecting part 31 of the measuring mechanism 3 and the connecting sub-nut 7 form a clamp on the connected part 8, and the second position of the second end of the connecting screw 2 in the connecting part 31 is obtained through the measuring structure 32 of the measuring mechanism 3.

[0107] Specifically, performing a zeroing operation on the measuring mechanism 3 of the clamping length measuring device is to determine the above-mentioned first position, and taking the first position as the reference position.

[0108] The connecting part 31 of the measuring mechanism 3 of the clamping length measuring device after the zeroing operation is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting sub-nut 7 (i.e., the second end), and the connecting part 31 of the measuring mechanism 3 and the connecting sub-nut 7 form a clamp on the connected part 8, that is, the two ends of the connected part 8 located on the axis of the connecting screw 2 are respectively abutted against the connecting sub-nut 7 and the connecting part 31. At this time, the current position of the second end of the connecting screw 2 in the connecting part 31 (recorded as the second position) is obtained through the measuring structure 32 of the measuring mechanism 3.

[0109] Step 800: Determine the clamping length of the threaded connection pair to be measured according to the second position.

[0110] Specifically, in the axial direction of the connecting part 31, the displacement change (or distance) of the second position relative to the first position (reference position) is equal to the distance from the end of the internal thread of the connecting pair nut 7 facing the connected part 8 to the end of the connecting part 31 facing the connecting pair nut 7 in the axial direction of the screw. That is to say, the second position of the second end of the connecting screw 2 in the connecting part 31 obtained when the end of the connecting part 31 facing the connecting pair nut 7 abuts against the connected part 8, and its distance from the first position in the axial direction of the connecting part 31 is the clamping length of the threaded connection to be measured.

[0111] In this way, the method of this embodiment can accurately measure the distance from the support surface of the bolt used in the threaded connection pair to be measured (or the end surface of the connected part 8 away from the end of the connection pair nut 7) to the first tooth of the nut (or the end point of the internal thread of the nut facing the end of the connected part 8) based on the clamping length measuring device, and accurately measure the clamping length of the threaded connection pair to be measured. Moreover, during the measurement process, the connected part 8 is set on the connecting screw 2 through its hole sleeve for accommodating the bolt, and the connected part 8 is clamped by the connecting part 31 and the connection pair nut 7 to simulate the actual assembly of the threaded connection pair, thereby improving the accuracy of the clamping length measurement of the threaded connection pair.

[0112] For the clamping length measuring device used in the method of this embodiment, specifically, the positioning screw 1 has a screw portion 11 and a polished rod portion 12 that are integrally formed and coaxially arranged to improve the overall structural strength of the positioning screw 1. The screw portion 11 and the polished rod portion 12 are both cylindrical, and the outer side wall of the screw portion 11 is provided with an external thread that matches the internal thread of the connection pair nut 7 of the threaded connection pair to be measured. The diameter of the smooth rod portion 12 is designed to be larger than the inner diameter of the external thread of the screw portion 11, so that when the positioning screw 1 is threadedly connected with the internal thread of the corresponding nut (such as the connecting sub-nut 7) through the external thread of the screw portion 11, the smooth rod portion 12 can limit the threaded connection between the screw portion 11 and the nut. That is to say, when the screw portion 11 is screwed into the nut, the external thread of the screw portion 11 cooperates with the internal thread of the nut until the end of the internal thread of the nut facing the smooth rod portion 12 abuts against the end of the smooth rod portion 12 facing the nut (at this time, the positioning screw 1 is said to be completely screwed into the nut). Since the diameter of the smooth rod portion 12 is larger than the inner diameter of the external thread of the screw portion 11, the smooth rod portion 12 cannot be screwed into the corresponding nut, thereby limiting the relative position of the positioning screw 1 and the corresponding nut ( That is, the positioning screw 1 is limited to continue to be screwed into the corresponding nut, and there is no limit effect on the positioning screw 1 being screwed out of the corresponding nut in the opposite direction); and the diameter of the light rod portion 12 is less than or equal to the outer diameter of the external thread of the screw portion 11, so that when the positioning screw 1 is screwed into a nut (such as a countersunk nut) with a non-threaded section in the internal threaded hole, it is ensured that the positioning screw 1 can be completely screwed into the nut, that is, it is ensured that the end of the light rod portion 12 facing the nut can abut against the end of the internal thread of the nut facing the light rod portion 12, so as to avoid the situation that the end of the light rod portion 12 facing the nut interferes with the non-threaded section of the internal threaded hole of the nut due to the diameter of the light rod portion 12 being greater than the outer diameter of the external thread, and then the end of the light rod portion 12 facing the nut cannot abut against the end of the internal thread of the nut facing the light rod portion 12. In this way, it is ensured that the positioning screw 1 can be completely screwed into different types of connection pair nuts 7, so as to ensure that the clamping length measuring device can accurately measure the clamping length of the threaded connection pair to be measured. In addition, the connecting screw 2 is a cylindrical rod body with external threads, and its external threads are adapted to the internal threads of the positioning screw 1 at the end of the smooth rod portion 12 away from the screw portion 11, which is provided with an internal thread blind hole (i.e., a blind hole with internal threads on the hole wall), so that either end of the connecting screw 2 can be threadedly connected with the positioning screw 1 at the internal thread blind hole. The measuring mechanism 3 includes a hollow connecting portion 31 and a measuring structure 32 arranged thereon, the connecting portion 31 is used to be sleeved on the connecting screw 2, and the measuring structure 32 is used to measure the position of one end of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31.

[0113] Alternatively, if Figure 8-Figure 13 As shown, after step 500 and before step 700, the clamping length measurement method further includes:

[0114] Step 600: Sleeve the fixing nut 4 onto the connecting screw 2 from the second end of the connecting screw 2, and make the fixing nut 4 and the connecting auxiliary nut 7 clamp the connected part 8.

[0115] Specifically, when it is necessary to fix the nut 4 to ensure the stability of the relative position between the connected part 8 and the connecting screw 2, after step 500 and before step 700, through step 600, the fixing nut 4 of the clamping length measuring device is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting sub-nut 7 (i.e., the second end), and the fixing nut 4 and the connecting sub-nut 7 form a stable clamp on the connected part 8. Alternatively, when the fixing nut 4 is needed to eliminate the corresponding gap or clearance of the connected part 8 where there is a gap or clearance (or called an opening), after step 500 and before step 700, through step 600, the fixing nut 4 of the clamping length measuring device is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting pair nut 7 (i.e., the second end), and the fixing nut 4 and the connecting pair nut 7 form a stable clamp on the connected part 8. During this period, the corresponding gap or clearance of the connected part 8 can be eliminated by tightening the fixing nut 4 (such as applying the necessary fitting torque to the fixing nut 4), thereby ensuring that the clamping length of the threaded connection pair to be measured that is finally measured is true and accurate.

[0116] Step 800 includes:

[0117] The clamping length of the threaded connection pair to be measured is determined according to the second measured value and the axial length of the fixing nut 4 .

[0118] Based on the fact that the fixing nut 4 is sleeved on the connecting screw 2 from the second end of the connecting screw 2 in step 600, and the fixing nut 4 and the connecting sub-nut 7 form a clamp on the connected part 8, then in step 700, the measuring mechanism 3 after the zeroing operation is sleeved on the connecting screw 2 from the second end of the connecting screw 2, and the connecting part 31 of the measuring mechanism 3 is clamped on the connected part 8 through the fixing nut 4 and the connecting sub-nut 7, and the second measurement value of the second position of the second end of the connecting screw 2 in the connecting part 31 corresponding to the current measurement structure 32 is obtained. Thereafter, through step 800, considering that the displacement change (or distance) of the second position relative to the first position (reference position) in the axial direction of the connecting part 31 is equal to the distance from the end of the internal thread of the connecting pair nut 7 facing the connected part 8 in the axial direction of the screw to the end of the connecting part 31 facing the connecting pair nut 7, and there is a fixing nut 4 between the connected part 8 and the connecting part 31, therefore, the distance between the second position and the first position in the axial direction of the connecting part 31 is the sum of the clamping length of the threaded connection pair to be measured and the axial length of the fixing nut 4 (that is, the length of the fixing nut 4 in its own axial direction). In other words, the clamping length of the threaded connection pair to be measured is the difference between the distance between the second position and the first position in the axial direction of the connecting part 31 and the axial length of the fixing nut 4.

[0119] Alternatively, if Figure 3 , Figure 5 and Fig.14 As shown, after step 100 and before step 300, the clamping length measurement method further includes:

[0120] Step 210, selecting a standard nut 5 that matches the positioning screw 1;

[0121] Step 220, completely screw the positioning screw 1 into the standard nut 5;

[0122] Step 230, connecting the first end of the positioning screw 1 and the connecting screw 2;

[0123] Step 240: Sleeve the measuring mechanism 3 on the connecting screw 2 from the second end of the connecting screw 2, and make the connecting portion 31 of the measuring mechanism 3 abut against the standard nut 5, and obtain the first position of the second end of the connecting screw 2 in the connecting portion 31 through the measuring structure 32;

[0124] Step 250 , setting the first position as the reference position, and performing a zeroing operation on the measuring mechanism 3 .

[0125] When the measuring mechanism 3 is reset, the standard nut 5 is used. Specifically, through step 210, the standard nut 5 of the clamping length measuring device that is compatible with the positioning screw 1 selected in step 100 is selected, so that the positioning screw 1 can be screwed into the standard nut 5 through the screw portion 11, and the threaded connection between the standard nut 5 and the positioning screw 1 is realized. Through step 220, the positioning screw 1 is completely screwed into the standard nut 5, that is, the screw portion 11 of the positioning screw 1 is screwed into the standard nut 5 from either end of the standard nut 5, until the end of the smooth rod portion 12 of the positioning screw 1 facing the nut can abut against the end of the internal thread of the nut facing the smooth rod portion 12, at this time, the positioning screw 1 is completely screwed into the nut, and the end of the smooth rod portion 12 of the positioning screw 1 facing the nut is simultaneously abutted (or fitted, flush) with the end face of the nut facing the smooth rod portion 12. Through step 230, the first ends of the positioning screw 1 and the connecting screw 2 are connected, such as the first end of the connecting screw 2 is inserted into the internal thread blind hole of the positioning screw 1 and abuts against the bottom of the internal thread blind hole, so as to ensure the stability of the relative position of the positioning screw 1 and the connecting screw 2 and the accuracy of the subsequent measurement results. Through step 240, the measuring mechanism 3 is sleeved on the connecting screw 2 from the end (i.e., the second end) of the connecting screw 2 away from the standard nut 5, and the connecting portion 31 of the measuring mechanism 3 is abutted against the standard nut 5 (e.g., the second end). Figure 5As shown), the end face of the connecting portion 31 facing the standard nut 5 is in contact with (or fitted with) the end face of the standard nut 5 facing the connecting portion 31, and the current position of one end (i.e., the second end) of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31 is recorded as the first position. At this time, the distance from the first position in the axial direction of the connecting portion 31 to the end face of the connecting portion 31 facing the standard nut 5 is the distance from the end of the connecting screw 2 away from the positioning screw 1 (i.e., the second end) in the axial direction of the connecting screw 2 to the end of the light rod portion 12 of the positioning screw 1 facing the screw rod portion 11. Through step 250, the measuring mechanism 3 is reset, that is, the first position obtained in step 240 is set as the reference position. In this way, the distance between the second position obtained by the measuring mechanism 3 and the reference position in the axial direction of the connecting portion 31 is the clamping length of the threaded connection pair or the sum of the clamping length of the threaded connection pair and the axial length of the fixing nut 4.

[0126] Considering that the position of the second end of the connecting screw 2 in the connecting portion 31 may be indicated by a specific indication (measurement value) by the measuring mechanism 3 and displayed by the display structure 33, the clamping length measurement method is exemplarily described below based on the measurement value of the measuring mechanism 3.

[0127] In some embodiments, in step 700, the measuring mechanism 3 after the zeroing operation is sleeved on the connecting screw 2 from the second end of the connecting screw 2, and the connecting portion 31 of the measuring mechanism 3 and the connecting sub-nut 7 are clamped on the connected member 8, and the second measurement value of the measuring structure 32 of the measuring mechanism 3 corresponding to the second position of the second end of the connecting screw 2 in the connecting portion 31 is obtained. Specifically, the zeroing operation of the measuring mechanism 3 of the clamping length measuring device is to determine the above-mentioned first position. When determining the first position, the indication of the current first measurement value of the measuring structure 32 is cleared to zero, that is, the indication 0 of the measuring structure 32 after the zeroing operation corresponds to the first position of one end of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31, and the first position is used as the reference position of the one end of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31, and the indication of the measuring structure 32 corresponding to the reference position is 0.

[0128] The connection part 31 of the measuring mechanism 3 of the clamping length measuring device after the zeroing operation is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting sub nut 7 (i.e., the second end), and the connection part 31 of the measuring mechanism 3 and the connecting sub nut 7 form a clamp on the connected member 8, that is, the two ends of the connected member 8 located on the axis of the connecting screw 2 are respectively in contact with the connecting sub nut 7 and the connection part 31. At this time, the current measurement value of the measuring structure 32 of the measuring mechanism 3 is obtained (recorded as the second measurement value). Among them, the second measurement value corresponds to the position of one end (i.e., the second end) of the connecting screw 2 extending into the connecting part 31 in the connecting part 31 when the connection part 31 of the measuring mechanism 3 and the connecting sub nut 7 form a clamp on the connected member 8 (recorded as the second position).

[0129] In step 800, the clamping length of the threaded connection pair to be measured is determined according to the second measurement value.

[0130] Specifically, based on the fact that the second measurement value is obtained based on the measuring mechanism 3 after the zeroing operation, the change of the second measurement value relative to 0 is the absolute value of the second measurement value, which is equal to the displacement change (or distance) of the second position relative to the first position (reference position) in the axial direction of the connecting part 31, and is also equal to the distance from the end of the internal thread of the connecting pair nut 7 facing the connected part 8 to the end of the connecting part 31 facing the connecting pair nut 7 in the axial direction of the screw. That is to say, when obtaining the second measurement value, if the end of the connecting part 31 facing the connecting pair nut 7 is in contact with the connected part 8, the absolute value of the second measurement value is the clamping length of the threaded connection to be measured.

[0131] In some embodiments, Figure 8-Figure 13 As shown, after step 500 and before step 700, the clamping length measurement method further includes:

[0132] Step 600: Sleeve the fixing nut 4 onto the connecting screw 2 from the second end of the connecting screw 2, and make the fixing nut 4 and the connecting auxiliary nut 7 clamp the connected part 8.

[0133] Specifically, when it is necessary to fix the nut 4 to ensure the stability of the relative position between the connected part 8 and the connecting screw 2, after step 500 and before step 700, through step 600, the fixing nut 4 of the clamping length measuring device is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting sub-nut 7 (i.e., the second end), and the fixing nut 4 and the connecting sub-nut 7 form a stable clamp on the connected part 8. Alternatively, when the fixing nut 4 is needed to eliminate the corresponding gap or clearance of the connected part 8 where there is a gap or clearance (or called an opening), after step 500 and before step 700, through step 600, the fixing nut 4 of the clamping length measuring device is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting pair nut 7 (i.e., the second end), and the fixing nut 4 and the connecting pair nut 7 form a stable clamp on the connected part 8. During this period, the corresponding gap or clearance of the connected part 8 can be eliminated by tightening the fixing nut 4 (such as applying the necessary fitting torque to the fixing nut 4), thereby ensuring that the clamping length of the threaded connection pair to be measured that is finally measured is true and accurate.

[0134] Step 700 includes:

[0135] The measuring mechanism 3 after the zeroing operation is sleeved on the connecting screw 2 from the second end of the connecting screw 2, and the connecting part 31 of the measuring mechanism 3 is clamped on the connected part 8 through the fixing nut 4 and the connecting sub-nut 7 to obtain the second measurement value of the second position of the second end of the connecting screw 2 in the connecting part 31 corresponding to the current measuring structure 32.

[0136] Specifically, the connecting portion 31 of the measuring mechanism 3 of the clamping length measuring device after the zeroing operation is sleeved on the connecting screw 2 from the end of the connecting screw 2 away from the connecting sub-nut 7 (i.e., the second end), and the connecting portion 31 of the measuring mechanism 3 is clamped on the connected member 8 through the fixing nut 4 and the connecting sub-nut 7, that is, the two ends of the connected member 8 located on the axis of the connecting screw 2 are respectively abutted against the connecting sub-nut 7 and the fixing nut 4, and the end of the fixing nut 4 away from the connected member 8 is abutted against the connecting portion 31. At this time, the current measurement value of the measuring structure 32 of the measuring mechanism 3 is obtained (recorded as the second measurement value), wherein the second measurement value corresponds to the position of one end (i.e., the second end) of the connecting screw 2 extending into the connecting portion 31 when the connecting portion 31 of the measuring mechanism 3 and the connecting sub-nut 7 clamp the connected member 8 in the connecting portion 31 (recorded as the second position).

[0137] Step 800 includes:

[0138] The clamping length of the threaded connection pair to be measured is determined according to the second measured value and the axial length of the fixing nut 4 .

[0139] Considering that the absolute value of the second measurement value reflects the distance between the first position (reference position) and the second position in the axial direction of the connection part 31, it is also the distance from the end of the internal thread of the connection nut 7 facing the connected member 8 to the end of the connection part 31 facing the connection nut 7 in the axial direction of the connecting screw 2. When obtaining the second measurement value, if the end of the connection part 31 facing the connection nut 7 abuts against the fixing nut 4, the absolute value of the second measurement value is equal to the distance from the end of the fixing nut 4 away from the connection nut 7 to the end of the internal thread of the connection nut 7 facing the connected member 8. Therefore, the clamping length of the threaded connection pair to be measured is the difference between the absolute value of the second measurement value and the axial length of the fixing nut 4 (i.e., the length of the fixing nut 4 in its own axial direction).

[0140] In some embodiments, Figure 3 , Figure 5 , Fig.14 As shown, after step 100 and before step 300, the clamping length measurement method further includes:

[0141] Step 210, selecting a standard nut 5 that matches the positioning screw 1;

[0142] Step 220, completely screw the positioning screw 1 into the standard nut 5;

[0143] Step 230, connecting the first end of the positioning screw 1 and the connecting screw 2;

[0144] Step 240: Sleeve the measuring mechanism 3 on the connecting screw 2 from the second end of the connecting screw 2, and make the connecting portion 31 of the measuring mechanism 3 abut against the standard nut 5, and obtain a first measurement value of the measuring structure 32 corresponding to the first position of the second end of the connecting screw 2 in the connecting portion 31;

[0145] Step 250: clear the first measurement value, set the first position as a reference position, and calculate subsequent measurement values ​​of the measurement mechanism 3 relative to the reference position.

[0146] When the measuring mechanism 3 is reset, the standard nut 5 is used. Specifically, through step 210, the standard nut 5 of the clamping length measuring device that is compatible with the positioning screw 1 selected in step 100 is selected, so that the positioning screw 1 can be screwed into the standard nut 5 through the screw portion 11, and the threaded connection between the standard nut 5 and the positioning screw 1 is realized. Through step 220, the positioning screw 1 is completely screwed into the standard nut 5, that is, the screw portion 11 of the positioning screw 1 is screwed into the standard nut 5 from either end of the standard nut 5, until the end of the smooth rod portion 12 of the positioning screw 1 facing the nut can abut against the end of the internal thread of the nut facing the smooth rod portion 12, at this time, the positioning screw 1 is completely screwed into the nut, and the end of the smooth rod portion 12 of the positioning screw 1 facing the nut is simultaneously abutted (or fitted, flush) with the end face of the nut facing the smooth rod portion 12. Through step 230, the first ends of the positioning screw 1 and the connecting screw 2 are connected, such as the first end of the connecting screw 2 is inserted into the internal thread blind hole of the positioning screw 1 and abuts against the bottom of the internal thread blind hole, so as to ensure the stability of the relative position of the positioning screw 1 and the connecting screw 2 and the accuracy of the subsequent measurement results. Through step 240, the measuring mechanism 3 is sleeved on the connecting screw 2 from the end (i.e., the second end) of the connecting screw 2 away from the standard nut 5, and the connecting portion 31 of the measuring mechanism 3 is abutted against the standard nut 5 (e.g., the second end). Figure 5 As shown), the end face of the connecting portion 31 facing the standard nut 5 is abutted (or fitted) with the end face of the standard nut 5 facing the connecting portion 31, and the current position of one end (i.e., the second end) of the connecting screw 2 extending into the connecting portion 31 in the connecting portion 31 is recorded as the first position. At this time, the distance from the first position to the end face of the connecting portion 31 facing the standard nut 5 in the axial direction of the connecting portion 31 is the distance from the end of the connecting screw 2 away from the positioning screw 1 (i.e., the second end) in the axial direction of the connecting screw 2 to the end of the light rod portion 12 of the positioning screw 1 facing the screw portion 11. The measurement value of the measuring structure 32 corresponding to the first position is recorded as the first measurement value. Through step 250, the first measurement value obtained by step 240 is set to zero, and the first position corresponding to the first measurement value is set as the reference position. The subsequent measurement values ​​of the measuring mechanism 3 are calculated relative to the reference position. That is to say, the subsequent measurements will be calculated based on this reference position, and any subsequent measurement values ​​represent changes relative to the reference position, so that the subsequent measurement values ​​(or the absolute values ​​of the measurement values) of the measuring mechanism 3 can directly show the clamping length of the threaded connection pair to be measured.

[0147] Alternatively, if Figure 1 , Figure 2 As shown, the measuring mechanism 3 further includes a display structure 33 which is in communication connection with the measuring structure 32 , and the display structure 33 is used to display the clamping length of the threaded connection pair to be measured.

[0148] In this optional embodiment, the display structure 33 is used to display the clamping length of the threaded connection pair to be measured, so as to intuitively show the measured clamping length of the threaded connection pair to be measured to the user, thereby improving the user's experience of using the clamping length measuring device. The display structure 33 can be set on the connecting portion 31, or separated from the connecting portion 31; when the display structure 33 is separated from the connecting portion 31, the display structure 33 and the measuring structure 32 are connected by wired communication or wireless communication.

[0149] The display structure 33 is connected to the measuring structure 32 in communication, and can be used to display the parameters measured by the measuring structure 32, the parameters such as the clamping length of the threaded connection pair to be measured obtained by conversion (conversion) based on the parameters measured by the measuring structure 32, etc. Exemplarily, the display structure 33 is used to display the parameters currently measured by the measuring structure 32, or to display the parameters indirectly obtained based on the parameters currently measured by the measuring structure 32, for example, the display structure 33 is used to display the real-time displacement value of the connecting screw 2 extending into the connecting part 31 measured by the measuring structure 32 or the distance between one end of the connecting screw 2 extending into the connecting part 31 and the fixed reference point of the connecting part 31; display the reference value after the zeroing operation (i.e., the first measured value measured during zeroing), and the real-time displacement difference (or distance) compared with the reference value; display the contact status prompt information of the connecting screw 2 and the standard nut 5, the connected part 8 or the fixed nut 4 during the measurement process; display the final measured value and the clamping length confirmation prompt after the measurement is completed; or display the zeroing operation confirmation information to prompt whether the zeroing state is successful or needs to be re-operated; and so on.

[0150] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A clamping length measuring device, characterized in that: The device is used to measure the clamping length of a threaded connection pair to be measured, wherein the threaded connection pair to be measured comprises a connection pair nut (7), and the clamping length measuring device comprises: A positioning screw (1), the positioning screw (1) comprising a screw portion (11) and a smooth rod portion (12) which are integrally formed and coaxially arranged, the outer wall of the screw portion (11) being provided with an external thread adapted to match the internal thread of the connecting nut (7), the diameter of the smooth rod portion (12) being larger than the inner diameter of the external thread of the screw portion (11) and smaller than or equal to the outer diameter of the external thread of the screw portion (11), and an internally threaded blind hole being provided at one end of the smooth rod portion (12) away from the screw portion (11); A connecting screw (2), wherein a first end of the connecting screw (2) is provided with an external thread matching the internal thread of the internal thread blind hole; A measuring mechanism (3), the measuring mechanism (3) comprising a hollow connecting portion (31) and a measuring structure (32) arranged on the connecting portion (31), the measuring structure (32) being used to monitor the position of the second end of the connecting screw (2) in the connecting portion (31) when the connecting portion (31) is sleeved on the connecting screw (2), so as to display the clamping length of the threaded connection pair to be measured based on the position.

2. The clamping length measuring device according to claim 1, characterized in that: It also includes a fixing nut (4), the internal thread of the fixing nut (4) is compatible with the external thread of the connecting screw (2), and the end faces of the fixing nut (4) at both ends of its own axis are perpendicular to its own axis.

3. The clamping length measuring device according to claim 1, characterized in that: The connecting portion (31) comprises a first columnar portion (311), wherein the first columnar portion (311) is provided with a receiving hole (311a) for receiving the connecting screw (2); Alternatively, the connecting portion (31) includes a first columnar portion (311) and a second columnar portion (312) that are integrally formed and coaxially arranged, the first columnar portion (311) is provided with a receiving hole (311a), the second columnar portion (312) is provided with a through hole (312a) connected to the receiving hole (311a), the connected receiving hole (311a) and the through hole (312a) are used to accommodate the connecting screw (2), and the diameter of the through hole (312a) is greater than or equal to the diameter of the light rod portion (12), and the axial length of the second columnar portion (312) is greater than or equal to the axial length of the light rod portion (12).

4. The clamping length measuring device according to claim 3, characterized in that: The outer side wall of the connecting screw (2) is provided with an external thread, and the external thread of the connecting screw (2) extends from the first end to the second end of the connecting screw (2); The accommodating hole (311a) is a cylindrical hole, the diameter of which is greater than or equal to the outer diameter of the external thread of the connecting screw (2); or, the accommodating hole (311a) is a cylindrical hole, and the hole wall of the cylindrical hole is provided with an internal thread for matching with the external thread of the connecting screw (2).

5. The clamping length measuring device according to any one of claims 1 to 4, characterized in that: It also includes a standard nut (5), the internal thread of the standard nut (5) is adapted to the external thread of the screw portion (11), the end faces of the standard nut (5) at both ends of its own axis are perpendicular to its own axis, and the two ends of the internal thread of the standard nut (5) are respectively flush with the end faces of the standard nut (5) at both ends of its own axis.

6. The clamping length measuring device according to any one of claims 1 to 4, characterized in that: The measuring structure (32) comprises a distance measuring structure (32), and the distance measuring structure (32) is used to measure the distance between an end of the connecting screw (2) extending into the connecting portion (31) and a fixed reference point on the connecting portion (31) on the axis of the connecting portion (31); Alternatively, the measuring structure (32) comprises a displacement measuring structure (32), and the displacement measuring structure (32) is used to measure the length of the connecting screw (2) extending into the connecting portion (31) along the axis of the connecting portion (31).

7. The clamping length measuring device according to any one of claims 1 to 4, characterized in that: The measuring mechanism (3) further comprises a display structure (33) which is communicatively connected to the measuring structure (32), and the display structure (33) is used to display the clamping length of the threaded connection pair to be measured.

8. A method for measuring clamping length, characterized in that: Based on the clamping length measuring device according to any one of claims 1 to 7, the clamping length measuring method comprises: Selecting a positioning screw (1) that matches the connection pair nut (7) of the threaded connection pair to be measured; Screwing the positioning screw (1) completely into the connecting nut (7); Connecting the positioning screw (1) and the first end of the connecting screw (2); Sleeve the connected member (8) of the threaded connection pair to be measured onto the connecting screw (2); The measuring mechanism (3) after the zeroing operation is sleeved onto the connecting screw (2) from the second end of the connecting screw (2), and the connecting portion (31) of the measuring mechanism (3) and the connecting sub-nut (7) are clamped on the connected member (8), and the second position of the second end of the connecting screw (2) in the connecting portion (31) is obtained through the measuring structure (32) of the measuring mechanism (3); According to the second position, the clamping length of the threaded connection pair to be measured is determined.

9. The clamping length measurement method according to claim 8, characterized in that: After the connected member (8) of the threaded connection pair to be measured is sleeved on the connecting screw (2), the measuring mechanism (3) after the zeroing operation is sleeved from the second end of the connecting screw (2) to the front of the connecting screw (2), and the clamping length measurement method further includes: The fixing nut (4) is sleeved onto the connecting screw (2) from the second end of the connecting screw (2), and the fixing nut (4) and the connecting auxiliary nut (7) are clamped on the connected member (8); Determining the clamping length of the threaded connection pair to be measured according to the second position includes: The clamping length of the threaded connection pair to be measured is determined according to the second position and the axial length of the fixing nut (4).

10. The clamping length measurement method according to claim 8, characterized in that: After selecting a positioning screw (1) that matches the connection pair nut (7) of the threaded connection pair to be measured, and before completely screwing the positioning screw (1) into the connection pair nut (7), the clamping length measurement method further comprises: Selecting a standard nut (5) that matches the positioning screw (1); Screw the positioning screw (1) completely into the standard nut (5); Connecting the positioning screw (1) and the first end of the connecting screw (2); The measuring mechanism (3) is sleeved onto the connecting screw (2) from the second end of the connecting screw (2), and the connecting portion (31) of the measuring mechanism (3) is brought into contact with the standard nut (5), and a first position of the second end of the connecting screw (2) in the connecting portion (31) is obtained through the measuring structure (32); The first position is set as a reference position, and a zeroing operation is performed on the measuring mechanism (3).

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