A method and tool for measuring a pin profile

Abstract

The application provides a stepped internal thread measuring method and a measuring tool. The stepped internal thread measuring tool comprises a thread section TS1, a thread section TS2, a thread section ZS1, a thread section ZS2 and a thread section ZS3. The thread section TS1 is used for judging whether the first tooth flank profile line, the second tooth flank profile line and the fifth tooth flank profile line are out of the tolerance band range. The thread section TS2 is used for judging whether the third tooth flank profile line and the fifth tooth flank profile line are out of the tolerance band range. The thread section ZS1 is used for judging whether the first tooth flank profile line and the fifth tooth flank profile line are out of the tolerance band range. The thread section ZS2 is used for judging whether the second tooth flank profile line and the fifth tooth flank profile line are out of the tolerance band range. The thread section ZS3 is used for judging whether the third tooth flank profile line and the fifth tooth flank profile line are out of the tolerance band range. The measuring tool does not need to participate in auxiliary equipment, the measuring process is simple, and the measuring efficiency can be improved and the measuring cost can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical manufacturing, and particularly relates to a stepped internal thread measuring method and a measuring tool. BACKGROUND

[0002] Threaded connection structure is widely used in the fields of machinery, transportation, construction, aviation, aerospace, shipbuilding, furniture and the like due to its low cost, convenient disassembly and assembly, large connection force and the like. However, in the actual use process, the threaded connection structure is very easy to loosen due to various complex working conditions such as vibration and impact. The loosening of the threaded connection structure not only reduces the connection force, leading to connection failure, but also causes serious safety accidents. Therefore, it is necessary to adopt certain anti-loosening measures.

[0003] A Chinese invention ZL2020207103546 discloses an anti-loosening thread containing a stepped structure, which is referred to as a stepped thread herein. The stepped thread has excellent anti-loosening effect and can effectively solve the loosening problem of the threaded connection. However, due to the small size of the step in the stepped structure, the measurement of the stepped thread is difficult, which directly affects the product quality and production efficiency. SUMMARY

[0004] The present application provides a stepped internal thread measuring method and a measuring tool to solve the technical problem that the measurement process of the stepped thread is difficult.

[0005] The first aspect of the present application provides a box thread measuring tool for measuring a box thread, the tooth profile line of the box thread comprising a first flank profile line, a second flank profile line, a third flank profile line, a fourth root profile line, a fifth flank profile line and a sixth crest profile line connected in sequence; wherein the first flank profile line, the second flank profile line and the third flank profile line are connected in sequence to form a stepped generatrix; characterized in that the box thread measuring tool comprises a through-end plug gauge and a dead-end plug gauge; the through-end plug gauge comprises a thread segment TS1 and a thread segment TS2; wherein the thread segment TS1 is used to determine whether the first flank profile line, the second flank profile line and the fifth flank profile line of the tooth profile line of the box thread exceed the tolerance band range from the side of the maximum solid tooth form of the box thread; the thread segment TS2 is used to determine whether the third flank profile line and the fifth flank profile line of the tooth profile line of the box thread exceed the tolerance band range from the side of the maximum solid tooth form of the box thread; the dead-end plug gauge comprises a thread segment ZS1, a thread segment ZS2 and a thread segment ZS3; wherein the thread segment ZS1 is used to determine whether the first flank profile line and the fifth flank profile line of the tooth profile line of the box thread exceed the tolerance band range from the side of the minimum solid tooth form of the box thread; the thread segment ZS2 is used to determine whether the second flank profile line and the fifth flank profile line of the tooth profile line of the box thread exceed the tolerance band range from the side of the minimum solid tooth form of the box thread; the thread segment ZS3 is used to determine whether the third flank profile line and the fifth flank profile line of the tooth profile line of the box thread exceed the tolerance band range from the side of the minimum solid tooth form of the box thread.

[0006] In some possible implementation manners, the profile line of the design tooth form of the thread segment TS1 comprises a flank profile line TS1-1, a flank profile line TS1-2, a flank profile line TS1-4 and a root profile line TS1-5; wherein, in the case that the thread axis of the box thread coincides with the thread axis of the thread segment TS1: the flank profile line TS1-1 can completely contain the first flank profile line of the maximum solid tooth form of the box thread, and at the same time, the flank profile line TS1-2 completely contains the second flank profile line of the maximum solid tooth form of the box thread, and at the same time, the flank profile line TS1-4 partially coincides with the fifth flank profile line of the maximum solid tooth form of the box thread, and at the same time, the root profile line TS1-5 has a first preset distance from the sixth crest profile line of the maximum solid tooth form of the box thread.

[0007] In some possible implementation manners, the profile line of the design tooth form of the thread segment TS1 further comprises a crest profile line TS1-3, the crest profile line TS1-3 is connected between the flank profile line TS1-2 and the flank profile line TS1-4, and the flank profile line TS1-3 is outside the tolerance band of the box thread.

[0008] In some possible implementation manners, the profile line of the design tooth profile of the thread segment TS2 includes a flank profile line TS2-1, a flank profile line TS2-3, a crest profile line TS2-2, and a root profile line TS2-4; wherein, in the case that the thread axis of the stepped internal thread and the thread segment TS2 coincide: the flank profile line TS2-1 can completely contain the third flank profile line of the maximum solid tooth profile of the stepped internal thread, and at the same time, the flank profile line TS2-3 completely contains the fifth flank profile line of the maximum solid tooth profile of the stepped internal thread, and at the same time, the crest profile line TS2-2 is outside the tolerance band of the stepped internal thread, and at the same time, the root profile line TS2-4 has a second preset distance from the sixth crest profile line of the maximum solid tooth profile of the stepped internal thread.

[0009] In some possible implementation manners, the profile line of the design tooth profile of the thread segment ZS1 includes a flank profile line ZS1-1, a flank profile line ZS1-3, a crest profile line ZS1-2, and a root profile line ZS1-4; wherein, in the case that the thread axis of the stepped internal thread and the thread segment ZS1 coincide: the flank profile line ZS1-1 can partially coincide with the first flank profile line of the minimum solid tooth profile of the stepped internal thread, and at the same time, the flank profile line ZS1-3 partially coincides with the fifth flank profile line of the minimum solid tooth profile of the stepped internal thread, and at the same time, the crest profile line ZS1-2 does not intersect the second flank profile line of the minimum solid tooth profile of the stepped internal thread, and at the same time, the crest profile line ZS1-2 also does not intersect the second flank profile line of the maximum solid tooth profile of the stepped internal thread, and at the same time, the root profile line ZS1-4 has a third preset distance from the sixth crest profile line of the maximum solid tooth profile of the stepped internal thread.

[0010] In some possible implementation manners, the profile line of the design tooth profile of the thread segment ZS2 includes a flank profile line ZS2-1, a flank profile line ZS2-2, a flank profile line ZS2-4, and a root profile line ZS2-5; wherein, in the case that the thread axis of the stepped internal thread and the thread segment ZS2 coincide: the flank profile line ZS2-2 can partially coincide with the second flank profile line of the minimum solid tooth profile of the stepped internal thread, and at the same time, the flank profile line ZS2-4 partially coincides with the fifth flank profile line of the minimum solid tooth profile of the stepped internal thread, and at the same time, the flank profile line ZS2-1 is outside the tolerance band of the stepped internal thread, and at the same time, the distance between the flank profile line ZS2-1 and the first flank profile line of the maximum solid tooth profile of the stepped internal thread in the direction of the thread axis is greater than the width of the tolerance band of the stepped internal thread in the direction of the thread axis, and at the same time, the root profile line ZS2-5 has a fourth preset distance from the sixth crest profile line of the maximum solid tooth profile of the stepped internal thread.

[0011] In some possible implementation manners, the profile line of the design thread form of the thread segment ZS2 further includes a crest profile line ZS2-3, and the crest profile line ZS2-3 is connected between the flank profile line ZS2-2 and the flank profile line ZS2-4.

[0012] In some possible implementation manners, the profile line of the design thread form of the thread segment ZS3 includes a flank profile line ZS3-1, a flank profile line ZS3-3, a crest profile line ZS3-2, and a root profile line ZS3-4; and in the case where the thread axis of the internal stepped thread and the thread segment ZS3 coincides: the flank profile line ZS3-1 can completely contain the third flank profile line of the minimum solid thread form of the internal stepped thread, and at the same time, the flank profile line ZS3-3 completely contains the fifth flank profile line of the minimum solid thread form of the internal stepped thread, and at the same time, the root profile line ZS3-4 has a fifth preset distance from the sixth crest profile line of the maximum solid thread form of the internal stepped thread.

[0013] The internal stepped thread measuring tool provided in the first aspect of the present application can detect different thread form profile lines of the measured internal stepped thread by means of the combined tool, without the participation of auxiliary equipment, and the measuring process is simple, which can not only improve the measuring efficiency but also effectively reduce the measuring cost. Moreover, the internal stepped thread measuring tool is designed in the form of a combined tool, which can effectively ensure the service life.

[0014] The internal stepped thread measuring method provided in the second aspect of the present application is applied to the internal stepped thread measuring tool provided in the first aspect, and is used for measuring the internal stepped thread. The internal stepped thread measuring method includes the following steps: the through-end plug gauge and the dead-end plug gauge are respectively screwed with the internal stepped thread; when the two thread segments of the through-end plug gauge can be screwed into the internal stepped thread, and the three thread segments of the dead-end plug gauge cannot be screwed into the internal stepped thread, it is determined that the actual size of the internal stepped thread is within the allowable tolerance range.

[0015] In some possible implementation manners, the internal stepped thread measuring method further includes: when any one of the thread segments of the through-end plug gauge cannot be screwed into the internal stepped thread, or any one of the thread segments of the dead-end plug gauge can be screwed into the internal stepped thread, it is determined that the actual size of the internal stepped thread is not within the allowable tolerance range.

[0016] The internal stepped thread measuring method provided in the second aspect of the present application can conveniently and quickly determine whether the size of the measured internal stepped thread is qualified, has the advantages of high measuring accuracy and high efficiency, and is simple, easy to implement, and convenient to operate, and does not require any auxiliary equipment, thereby effectively reducing the measuring cost. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0018] Figure 1 is a design tooth profile structure view of a stepped internal thread provided by the embodiments of the present application;

[0019] Figure 2 is a tolerance band structure schematic view of a stepped internal thread provided by the embodiments of the present application;

[0020] Figure 3 is a structure schematic view of a through-end plug gauge provided by the embodiments of the present application;

[0021] Figure 4 is a structure schematic view of a stop-end plug gauge provided by the embodiments of the present application;

[0022] Figure 5 is a design tooth profile structure schematic view of a thread segment TS1 provided by the embodiments of the present application;

[0023] Figure 6 is a design tooth profile structure schematic view of a thread segment TS2 provided by the embodiments of the present application;

[0024] Figure 7 is a design tooth profile structure schematic view of a thread segment ZS1 provided by the embodiments of the present application;

[0025] Figure 8 is a design tooth profile structure schematic view of a thread segment ZS2 provided by the embodiments of the present application;

[0026] Figure 9 is a design tooth profile structure schematic view of a thread segment ZS3 provided by the embodiments of the present application;

[0027] Figure 10 is a flow schematic view of a stepped internal thread measuring method provided by the embodiments of the present application.

[0028] Illustration mark:

[0029] 11-first tooth flank profile line; 12-second tooth flank profile line; 13-third tooth flank profile line; 14-fourth tooth bottom profile line; 15-fifth tooth flank profile line; 16-sixth tooth top profile line; L1-thread axis;

[0030] Minimum solid tooth flank: 11-1-first tooth flank profile line; 12-1-second tooth flank profile line; 13-1-third tooth flank profile line; 14-1-fourth tooth bottom profile line; 15-1-fifth tooth flank profile line; 16-1-sixth tooth top profile line;

[0031] Maximum entity tooth side: 11-2-1st tooth side profile line; 12-2-2nd tooth side profile line; 13-2-3rd tooth side profile line; 14-2-4th tooth bottom profile line; 15-2-5th tooth side profile line; 16-2-6th tooth top profile line;

[0032] 10- through end plug gauge; 20- end plug gauge. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0034] Hereinafter, the terms "first", "second", "A", "B", "I", "II", and the like are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", and the like can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0035] In addition, in the present application, the orientation terms such as "upper", "lower", "inner", "outer", "left", "right", "horizontal", and the like are defined with respect to the orientation in which the components in the drawings are placed, and it should be understood that these directional terms are relative concepts, which are used for relative description and clarification, and can be changed accordingly according to the change of the orientation in which the components are placed in the drawings.

[0036] The threaded connection structure is widely used in the fields of machinery, transportation, construction, aviation, aerospace, shipbuilding, furniture, etc. due to its low cost, easy disassembly and assembly, and large connection force. However, in actual use, due to various complex working conditions such as vibration and impact, the threaded connection structure is very easy to loosen. Thread loosening not only reduces the connection force and leads to connection failure, but also can cause serious safety accidents. Therefore, it is necessary to adopt certain anti-loosening measures.

[0037] There are anti-loosening threads containing stepped structures in existing designs, which are referred to as stepped threads in the present application, and have excellent anti-loosening effect, which can effectively solve the loosening problem of threaded connection. The stepped thread includes a stepped external thread and a stepped internal thread. Due to the small size of the step, the measurement of the stepped thread is difficult, which can easily lead to the missed detection of unqualified products, and also limits the equipment debugging speed during production, resulting in low production efficiency.

[0038] To solve the above technical problems, the application provides a step internal thread measuring method and a measuring tool, which have the advantages of simplicity, convenience, high measurement accuracy, low cost and high efficiency.

[0039] First, the terms related to threads used in the application will be defined.

[0040] The step thread described in the application refers to the thread provided with a step structure described in Chinese invention ZL2020207103546, specifically, it can be the thread of the third or fourth threaded part described in Chinese invention ZL2020207103546 when provided with a step structure. Specifically, the step thread in the application is a step internal thread.

[0041] Figure 1 It is a design tooth profile structure view of a step internal thread provided by an embodiment of the application.

[0042] Referring to Figure 1 , the tooth profile line of the step internal thread includes a first tooth flank profile line 11, a second tooth flank profile line 12, a third tooth flank profile line 13, a fourth tooth bottom profile line 14, a fifth tooth flank profile line 15 and a sixth tooth crest profile line 16 connected in sequence; wherein the first tooth flank profile line 11, the second tooth flank profile line 12 and the third tooth flank profile line 13 are connected in sequence to form a step-shaped generatrix, i.e. the profile shape of the tooth flank containing the step in the step internal thread axis plane; the fifth tooth flank profile line 15 is the profile shape of the tooth flank not containing the step in the step internal thread axis plane.

[0043] Various terms related to conventional threads and step threads used in the application, if defined in the national standard GB / T14791-2013, then in the absence of special instructions, the definitions in the national standard GB / T 14791-2013 can be adopted, such as tooth bottom, tooth flank, tooth crest, pitch, major diameter, minor diameter, tooth body, tooth profile, etc. These thread-related terms are also common sense for those skilled in the art, and their specific definitions will not be repeated here.

[0044] The special terms related to step threads described in the application, if defined in Chinese invention ZL2020207103546, then in the absence of special instructions, the definitions in Chinese invention ZL2020207103546 are preferred, such as step-shaped structure, step-shaped generatrix, etc. Their specific definitions will not be repeated here.

[0045] It needs to be specially pointed out that the tooth flanks of the stepped thread described in the present application refer to the helical surfaces on both sides of the tooth body of the stepped thread. The stepped thread described in the present application has two tooth flanks, one of which is a tooth flank not containing a step (i.e., a tooth flank not containing a step-like structure), and the other of which is a tooth flank containing a step (i.e., a tooth flank containing a step-like structure). The two tooth flanks of the conventional thread are both linear in the axial plane, the tooth flank of the stepped thread not containing a step is linear in the axial plane, and the tooth flank containing a step is curved in the axial plane, specifically, it contains the step-like generatrix described in Chinese Invention ZL2020207103546, i.e., the step-like generatrix described in the present application.

[0046] The axial plane described in the present application refers to a plane containing the thread axis, i.e., a cross section containing the thread axis. The conventional thread and the stepped thread both have their respective axial planes.

[0047] Figure 2 is a structural schematic diagram of the tolerance band of the stepped internal thread provided by the embodiments of the present application.

[0048] In actual production, the actual size of the stepped thread may have a machining error, and the allowable machining error range of the stepped internal thread (i.e., the tolerance band of the stepped internal thread) is as shown in Figure 2 Specifically, the actually machined stepped internal thread should be between its maximum solid tooth profile and minimum solid tooth profile. The maximum solid tooth profile is the tooth profile on the side close to the thread axis L1, and the minimum solid tooth profile is the tooth profile on the side away from the thread axis L1, and the shaded part in the figure is the tolerance band of the stepped internal thread. The minimum solid tooth profile is the tooth profile when the solid part is the smallest during the machining of the stepped internal thread of the workpiece during the machining process, i.e., the cut part is relatively more during machining. The maximum solid tooth profile is the tooth profile when the solid part is the largest during the machining of the stepped internal thread of the workpiece during the machining process, i.e., the cut part is relatively less during machining. Both the maximum solid tooth profile and the minimum solid tooth profile include the six-segment tooth profile lines of the stepped internal thread. The first tooth flank profile line 11-1, the second tooth flank profile line 12-1, the third tooth flank profile line 13-1, the fourth tooth bottom profile line 14-1, the fifth tooth flank profile line 15-1, and the sixth tooth top profile line 16-1 of the minimum solid tooth profile; the first tooth flank profile line 11-2, the second tooth flank profile line 12-2, the third tooth flank profile line 13-2, the fourth tooth bottom profile line 14-2, the fifth tooth flank profile line 15-2, and the sixth tooth top profile line 16-2 of the maximum solid tooth profile.

[0049] In actual production, the stepped internal thread product processed needs to be measured to confirm whether the actual processing size falls within the allowed tolerance range, and only then can it be considered as a qualified product. If the actual processing size does not fall within the allowed tolerance range, the processing parameters of the machine tool need to be optimized according to the measurement results until the actual processing size falls within the allowed tolerance range. Since the stepped internal thread structure is complex, the measurement is difficult, and the traditional thread measurement method cannot complete the fast and accurate measurement of the stepped internal thread.

[0050] Figure 3 is a structural schematic diagram of a through-end plug gauge provided by an embodiment of the present application.

[0051] Figure 4 is a structural schematic diagram of a dead-end plug gauge provided by an embodiment of the present application.

[0052] An embodiment of the present application provides a stepped internal thread measuring tool, which is a combined gauge including a through-end plug gauge 10 and a dead-end plug gauge 20. Wherein, referring to Figure 3 , the through-end plug gauge 10 includes two thread segments, which are a thread segment TS1 and a thread segment TS2. Referring to Figure 4 , the dead-end plug gauge 20 includes three thread segments, which are a thread segment ZS1, a thread segment ZS2 and a thread segment ZS3. Specifically, the thread segment TS1, the thread segment TS2, the thread segment ZS1, the thread segment ZS2 and the thread segment ZS3 are all external threads.

[0053] When the two thread segments of the through-end plug gauge 10 can be screwed into the measured stepped internal thread respectively, and the three thread segments of the dead-end plug gauge 20 cannot be screwed into the measured stepped internal thread, it can be determined that the actual size of the measured stepped internal thread is within the allowed tolerance range; when any one of the thread segments of the through-end plug gauge 10 cannot be screwed into the measured stepped internal thread, or any one of the thread segments of the dead-end plug gauge 20 can be screwed into the measured stepped internal thread, it can be determined that the actual size of the measured stepped internal thread is not within the allowed tolerance range.

[0054] It is worth noting that, as shown in Figure 3 , the through-end plug gauge 10 includes a through-end main body, and the thread segment TS1 and the thread segment TS2 are symmetrically arranged at two ends of the through-end main body. In other specific implementation manners, the thread segment TS1 and the thread segment TS2 can also be arranged on the through-end main body in other forms, for example, in the form of an included angle.

[0055] Similarly, as shown in Figure 4The shown end plug gauge 20 comprises an end body, and the thread segments ZS1, ZS2 and ZS3 are arranged in a form that the included angle between the thread axes of any two thread segments is 120°, and in other specific implementations, the thread segments ZS1, ZS2 and ZS3 can also be arranged on the end body in other forms.

[0056] Figure 5 is a design tooth profile structure schematic diagram of a thread segment TS1 provided by an embodiment of the present application. Wherein, Figure 5 The thread axis L1 of the measured internal stepped thread and the thread axis of the thread segment TS1 coincide.

[0057] Referring to Figure 5 , the design tooth profile contour line of the thread segment TS1 comprises a flank contour line TS1-1, a flank contour line TS1-2, a flank contour line TS1-4 and a root contour line TS1-5, and in the case that the thread axis L1 of the measured internal stepped thread and the thread axis of the thread segment TS1 coincide: the flank contour line TS1-1 can completely contain the first flank contour line 11-2 of the maximum solid tooth profile of the measured internal stepped thread, and at the same time, the flank contour line TS1-2 completely contains the second flank contour line 12-2 of the maximum solid tooth profile of the measured internal stepped thread, and at the same time, the flank contour line TS1-4 partially coincides with the fifth flank contour line 15-2 of the maximum solid tooth profile of the measured internal stepped thread, and at the same time, the root contour line TS1-5 has a first preset distance with the sixth top contour line 16-2 of the maximum solid tooth profile of the measured internal stepped thread, that is, the root contour line TS1-5 is outside the tolerance band of the measured internal stepped thread.

[0058] Optionally, the design tooth profile contour line of the thread segment TS1 further comprises a top contour line TS1-3, the top contour line TS1-3 is connected between the flank contour line TS1-2 and the flank contour line TS1-4, and the top contour line TS1-3 is outside the tolerance band of the internal stepped thread.

[0059] Optionally, the flank contour line TS1-1, the flank contour line TS1-2, the top contour line TS1-3, the flank contour line TS1-4 and the root contour line TS1-5 are sequentially connected.

[0060] Figure 6 is a design tooth profile structure schematic diagram of a thread segment TS2 provided by an embodiment of the present application. Wherein, Figure 6 The thread axis L1 of the measured internal stepped thread and the thread axis of the thread segment TS2 coincide.

[0061] Referring to Figure 6, the design tooth profile line of the thread segment TS2 includes a flank profile line TS2-1, a flank profile line TS2-3, a crest profile line TS2-2 and a root profile line TS2-4, in the case where the thread axis L1 of the measured internal stepped thread and the thread axis of the thread segment TS2 coincide: the flank profile line TS2-1 can completely contain the third flank profile line 13-2 of the maximum solid tooth profile of the measured internal stepped thread, and at the same time the flank profile line TS2-3 completely contains the fifth flank profile line 15-2 of the maximum solid tooth profile of the measured internal stepped thread, and at the same time the crest profile line TS2-2 is outside the tolerance band of the measured internal stepped thread, and at the same time the root profile line TS2-4 has a second preset distance from the sixth crest profile line 16-2 of the maximum solid tooth profile of the measured internal stepped thread, that is, the root profile line TS2-4 is outside the tolerance band of the measured internal stepped thread.

[0062] Optionally, the flank profile line TS2-1, the crest profile line TS2-2, the flank profile line TS2-3 and the root profile line TS2-4 are sequentially connected.

[0063] Specifically, the thread segment TS1 of the through-end plug gauge 10 is based on the fifth flank profile line 15 of the measured internal stepped thread to measure the positions of the first flank profile line 11 and the second flank profile line 12, if the thread segment TS1 that meets the design tooth profile requirements of the through-end plug gauge 10 can be screwed into the measured internal stepped thread, it indicates that the first flank profile line 11, the second flank profile line 12 and the fifth flank profile line 15 of the measured internal stepped thread are all not beyond the tolerance band range from the side of the maximum solid tooth profile of the internal stepped thread; on the contrary, if the thread segment TS1 that meets the design tooth profile requirements of the through-end plug gauge 10 cannot be screwed into the measured internal stepped thread, it indicates that the first flank profile line 11 or the second flank profile line 12 or the fifth flank profile line 15 of the measured internal stepped thread is beyond the tolerance band range from the side of the maximum solid tooth profile of the internal stepped thread, that is, the product is unqualified. Figure 5 Figure 5

[0064] The thread segment TS2 of the through-end plug gauge 10 is based on the fifth flank profile line 15 of the measured internal stepped thread to measure the position of the third flank profile line 13, if the thread segment TS2 that meets the design tooth profile requirements of the through-end plug gauge 10 can be screwed into the measured internal stepped thread, it indicates that the third flank profile line 13 and the fifth flank profile line 15 of the measured internal stepped thread are all not beyond the tolerance band range from the side of the maximum solid tooth profile of the internal stepped thread; on the contrary, if the thread segment TS2 that meets the design tooth profile requirements of the through-end plug gauge 10 cannot be screwed into the measured internal stepped thread, it indicates that the third flank profile line 13 or the fifth flank profile line 15 of the measured internal stepped thread is beyond the tolerance band range from the side of the maximum solid tooth profile of the internal stepped thread, that is, the product is unqualified. Figure 6 Figure 6

[0065] ​​​​It should be noted that the threaded segment TS1 and the threaded segment TS2 are used to measure different flank profiles on the spigot gauge 10, instead of measuring all flanks at the same time by an external thread segment that is completely consistent with the maximum solid tooth profile of the stepped internal thread, in order to facilitate the processing of the spigot gauge 10. In order to ensure the long-term use of the gauge, the gauge is usually made of very hard material, and thus needs to be processed by grinding. It is difficult to process an external thread segment that is completely consistent with the maximum solid tooth profile of the stepped internal thread by grinding. The spigot gauge 10 provided in the present application can achieve the measurement effect and facilitate the processing and manufacturing of the spigot gauge 10.

[0066] Figure 7 is a schematic diagram of a design tooth profile structure of a threaded segment ZS1 provided in an embodiment of the present application. In the design tooth profile structure of the threaded segment ZS1, the threaded axis L1 of the measured stepped internal thread coincides with the threaded axis of the threaded segment ZS1. Figure 7 In the design tooth profile structure of the threaded segment ZS1, the threaded axis L1 of the measured stepped internal thread coincides with the threaded axis of the threaded segment ZS1.

[0067] Referring to Figure 7 , the design tooth profile of the threaded segment ZS1 includes a flank profile ZS1-1, a flank profile ZS1-3, a crest profile ZS1-2, and a root profile ZS1-4. In the case where the threaded axis L1 of the measured stepped internal thread coincides with the threaded axis of the threaded segment ZS1, the flank profile ZS1-1 can partially coincide with the first flank profile 11-1 of the minimum solid tooth profile of the measured stepped internal thread, and at the same time, the flank profile ZS1-3 partially coincides with the fifth flank profile 15-1 of the minimum solid tooth profile of the measured stepped internal thread, and at the same time, the crest profile ZS1-2 does not intersect the second flank profile 12-1 of the minimum solid tooth profile of the measured stepped internal thread, and at the same time, the crest profile ZS1-2 also does not intersect the second flank profile 12-2 of the maximum solid tooth profile of the measured stepped internal thread, and at the same time, the root profile ZS1-4 has a third preset distance from the sixth crest profile 16-2 of the maximum solid tooth profile of the measured stepped internal thread, that is, the root profile ZS1-4 is outside the tolerance band of the measured stepped internal thread.

[0068] Optionally, the flank profile ZS1-1, the crest profile ZS1-2, the flank profile ZS1-3, and the root profile ZS1-4 are sequentially connected.

[0069] Figure 8 is a schematic diagram of a design tooth profile structure of a threaded segment ZS2 provided in an embodiment of the present application. In the design tooth profile structure of the threaded segment ZS2, the threaded axis L1 of the measured stepped internal thread coincides with the threaded axis of the threaded segment ZS2. Figure 8 In the design tooth profile structure of the threaded segment ZS2, the threaded axis L1 of the measured stepped internal thread coincides with the threaded axis of the threaded segment ZS2.

[0070] Referring to Figure 8In the case that the thread axis L1 of the measured internal stepped thread coincides with the thread axis of the thread segment ZS2, the flank profile ZS2-2 can partially coincide with the second flank profile 12-1 of the minimum solid profile of the measured internal stepped thread, and at the same time the flank profile ZS2-4 partially coincides with the fifth flank profile 15-1 of the minimum solid profile of the measured internal stepped thread, and at the same time the flank profile ZS2-1 is outside the tolerance band of the measured internal stepped thread, and at the same time the distance D1 between the flank profile ZS2-1 and the first flank profile 11-2 of the maximum solid profile of the measured internal stepped thread in the direction of the thread axis L1 is greater than the width D2 of the tolerance band of the measured internal stepped thread in the direction of the thread axis L1, and at the same time the root profile ZS2-5 has a fourth preset distance from the sixth crest profile 16-2 of the maximum solid profile of the measured internal stepped thread, that is, the root profile ZS2-5 is outside the tolerance band of the measured internal stepped thread.

[0071] Optionally, the design profile line of the thread segment ZS2 can further include a crest profile line ZS2-3, which is connected between the flank profile line ZS2-2 and the flank profile line ZS2-4.

[0072] Optionally, the flank profile line ZS2-1, the flank profile line ZS2-2, the crest profile line ZS2-3, the flank profile line ZS2-4 and the root profile line ZS2-5 are sequentially connected.

[0073] Figure 9 is a design profile structure schematic diagram of a thread segment ZS3 provided by an embodiment of the present application. Wherein, Figure 9 In the measured internal stepped thread, the thread axis L1 coincides with the thread axis of the thread segment ZS3.

[0074] Referring to Figure 9, the design tooth profile line of the thread segment ZS3 includes a flank profile line ZS3-1, a flank profile line ZS3-3, a crest profile line ZS3-2 and a root profile line ZS3-4, in the case where the thread axis L1 of the measured internal stepped thread and the thread axis of the thread segment ZS3 coincide: the flank profile line ZS3-1 can completely contain the third flank profile line 13-1 of the minimum solid tooth profile of the measured internal stepped thread, and at the same time the flank profile line ZS3-3 completely contains the fifth flank profile line 15-1 of the minimum solid tooth profile of the measured internal stepped thread, and at the same time the root profile line ZS3-4 has a fifth preset distance with the sixth crest profile line 16-2 of the maximum solid tooth profile of the measured internal stepped thread, that is, the root profile line ZS3-4 is outside the tolerance band of the measured internal stepped thread. Wherein, the first preset distance, the second preset distance, the third preset distance, the fourth preset distance and the fifth preset distance can be the same or different.

[0075] Optionally, the flank profile line ZS3-1, the crest profile line ZS3-2, the flank profile line ZS3-3 and the root profile line ZS3-4 are sequentially connected.

[0076] Specifically, the thread segment ZS1 of the end plug gauge 20 is measured from the fifth flank profile line 15 of the measured internal stepped thread to the position of the first flank profile line 11, if it meets the design tooth profile requirements of the thread segment ZS1 in the first preset distance, the second preset distance, the third preset distance and the fourth preset distance, the first flank profile line 11 of the measured internal stepped thread is within the tolerance band of the minimum solid tooth profile of the internal stepped thread. Figure 7 If the thread segment ZS1 of the design tooth profile requirements in the first preset distance, the second preset distance, the third preset distance and the fourth preset distance cannot be screwed into the measured internal stepped thread, it indicates that the first flank profile line 11 and the fifth flank profile line 15 of the measured internal stepped thread are both not outside the tolerance band from the side of the minimum solid tooth profile of the internal stepped thread. Figure 7 On the contrary, if the thread segment ZS1 of the design tooth profile requirements in the first preset distance, the second preset distance, the third preset distance and the fourth preset distance can be screwed into the measured internal stepped thread, it indicates that the first flank profile line 11 or the fifth flank profile line 15 of the measured internal stepped thread is outside the tolerance band from the side of the minimum solid tooth profile of the internal stepped thread, that is, the product is unqualified.

[0077] The thread segment ZS2 of the end plug gauge 20 is measured from the fifth flank profile line 15 of the measured internal stepped thread to the position of the second flank profile line 12, if it meets the design tooth profile requirements of the thread segment ZS2 in the first preset distance, the second preset distance, the third preset distance and the fourth preset distance, the second flank profile line 12 of the measured internal stepped thread is within the tolerance band of the minimum solid tooth profile of the internal stepped thread. Figure 8 If the thread segment ZS2 of the design tooth profile requirements in the first preset distance, the second preset distance, the third preset distance and the fourth preset distance cannot be screwed into the measured internal stepped thread, it indicates that the second flank profile line 12 and the fifth flank profile line 15 of the measured internal stepped thread are both not outside the tolerance band from the side of the minimum solid tooth profile of the internal stepped thread. Figure 8 On the contrary, if the thread segment ZS2 of the design tooth profile requirements in the first preset distance, the second preset distance, the third preset distance and the fourth preset distance can be screwed into the measured internal stepped thread, it indicates that the second flank profile line 12 or the fifth flank profile line 15 of the measured internal stepped thread is outside the tolerance band from the side of the minimum solid tooth profile of the internal stepped thread, that is, the product is unqualified.

[0078] The thread segment ZS3 of the end plug gauge 20 is measured based on the fifth flank profile 15 of the measured internal thread, and the position of the third flank profile 13 is measured. If the thread segment ZS3 of the designed tooth profile requirement cannot be screwed into the measured internal thread, it indicates that the third flank profile 13 and the fifth flank profile 15 of the measured internal thread are both out of the tolerance band range from the side of the minimum solid tooth profile of the internal thread. Figure 9 If the thread segment ZS3 of the designed tooth profile requirement can be screwed into the measured internal thread, it indicates that the third flank profile 13 or the fifth flank profile 15 of the measured internal thread is out of the tolerance band range from the side of the minimum solid tooth profile of the internal thread, that is, the product is unqualified. Figure 9 If the thread segment ZS3 of the designed tooth profile requirement can be screwed into the measured internal thread, it indicates that the third flank profile 13 or the fifth flank profile 15 of the measured internal thread is out of the tolerance band range from the side of the minimum solid tooth profile of the internal thread, that is, the product is unqualified.

[0079] It should be noted that the end plug gauge 20 uses three thread segments to measure different flank profiles, instead of using an external thread segment that is completely consistent with the minimum solid tooth profile of the internal thread to measure all flanks at the same time, in order to facilitate the machining of the end plug gauge 20. In order to ensure the long-term use of the plug gauge, the plug gauge is usually made of very hard material, and therefore needs to be processed by grinding. It is difficult to process an external thread segment that is completely consistent with the minimum solid tooth profile of the internal thread by grinding. The end plug gauge 20 scheme provided in the present application can achieve the measurement effect and facilitate the machining and manufacturing of the end plug gauge 20.

[0080] In addition, the end plug gauge 20 and the end plug gauge 20 provided in the present application do not measure the fourth root profile 14 and the sixth crest profile 16 of the internal thread, because the measurement of the actual accuracy of these two profiles can be realized by other conventional technologies, and is not the problem to be solved by the present application.

[0081] The internal thread measuring tool provided by the embodiment of the present application can detect different tooth profile lines of the measured internal thread by combining the tool, without the participation of auxiliary equipment, and the measurement process is simple, which can not only improve the measurement efficiency but also effectively reduce the measurement cost. Moreover, the internal thread measuring tool is designed in the form of a combined tool, which can effectively ensure the service life.

[0082] Corresponding to the foregoing embodiment of the internal thread measuring tool, the present application also provides an embodiment of an internal thread measuring method. The measuring method adopts the measuring tool provided by the foregoing embodiment.

[0083] Figure 10 is a flowchart of an internal thread measuring method provided by the embodiment of the present application.

[0084] Referring to Figure 10 , the measuring method can be realized by the following steps S1 to S3.

[0085] S1: screw the through-end plug gauge and the end-stop plug gauge into the internal step thread respectively.

[0086] In step S1, the threaded segments TS1, TS2, ZS1, ZS2 and ZS3 can be screwed into the measured internal step thread in any order.

[0087] S2: when both threaded segments of the through-end plug gauge can be screwed into the internal step thread, and all three threaded segments of the end-stop plug gauge cannot be screwed into the internal step thread, it can be determined that the actual size of the internal step thread is within the allowed tolerance range.

[0088] In step S2, when both threaded segments TS1 and TS2 can be screwed into the internal step thread, and none of the threaded segments ZS1, ZS2 and ZS3 can be screwed into the internal step thread, the measured internal step thread meets the design requirements, and the product is qualified.

[0089] S3: when any one of the threaded segments of the through-end plug gauge cannot be screwed into the internal step thread, or any one of the threaded segments of the end-stop plug gauge can be screwed into the internal step thread, it can be determined that the actual size of the internal step thread is not within the allowed tolerance range.

[0090] In step S3, when neither of the threaded segments TS1 and TS2 can be screwed into the internal step thread, and any one of the threaded segments ZS1, ZS2 and ZS3 can be screwed into the internal step thread, the measured internal step thread does not meet the design requirements, and the product is unqualified.

[0091] In the above measurement method, the geometric features of the through-end plug gauge and the end-stop plug gauge comply with the description of the step thread measurement tool in the foregoing embodiments, which will not be repeated here.

[0092] By the above method, it can be determined whether the size of the measured internal step thread is qualified conveniently and quickly, which has the advantages of high measurement accuracy and high efficiency, and the measurement method is simple, easy to operate, and does not require any auxiliary equipment, effectively reducing the measurement cost.

[0093] It should be noted that other embodiments of the application will occur to those skilled in the art after considering the specification and the practice of the application disclosed herein. The application is intended to cover any variations, uses or adaptive changes of the application falling within the general principles of the application and including those commonly known or customary within the technical field of the application. The specification and examples are considered to be exemplary only, and the true scope of the application is indicated by the claims.

[0094] It is to be understood that the application is not limited to the precise construction already described above and shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application should only be limited by the claims appended hereto.

Claims

1. A pin thread measuring tool for measuring a pin thread, a profile line of a tooth form of the pin thread comprising a first flank profile line, a second flank profile line, a third flank profile line, a fourth root profile line, a fifth flank profile line and a sixth crest profile line connected in sequence; wherein, The first tooth side profile line, the second tooth side profile line and the third tooth side profile line are sequentially connected to form a stepped generatrix; characterized in that the stepped internal thread measuring tool comprises a through-end plug gauge and a dead-end plug gauge; The through-end plug gauge comprises a threaded segment TS1 and a threaded segment TS2; wherein the threaded segment TS1 is used to determine whether the first tooth side profile line, the second tooth side profile line and the fifth tooth side profile line of the tooth profile line of the stepped internal thread exceed the tolerance band range from the side of the maximum solid tooth profile of the stepped internal thread; and the threaded segment TS2 is used to determine whether the third tooth side profile line and the fifth tooth side profile line of the tooth profile line of the stepped internal thread exceed the tolerance band range from the side of the maximum solid tooth profile of the stepped internal thread; The dead-end plug gauge comprises a threaded segment ZS1, a threaded segment ZS2 and a threaded segment ZS3; wherein the threaded segment ZS1 is used to determine whether the first tooth side profile line and the fifth tooth side profile line of the tooth profile line of the stepped internal thread exceed the tolerance band range from the side of the minimum solid tooth profile of the stepped internal thread; the threaded segment ZS2 is used to determine whether the second tooth side profile line and the fifth tooth side profile line of the tooth profile line of the stepped internal thread exceed the tolerance band range from the side of the minimum solid tooth profile of the stepped internal thread; and the threaded segment ZS3 is used to determine whether the third tooth side profile line and the fifth tooth side profile line of the tooth profile line of the stepped internal thread exceed the tolerance band range from the side of the minimum solid tooth profile of the stepped internal thread.

2. The stepped internal thread measuring tool according to claim 1, characterized in that the profile line of the design tooth profile of the threaded segment TS1 comprises a tooth side profile line TS1-1, a tooth side profile line TS1-2, a tooth side profile line TS1-4 and a tooth bottom profile line TS1-5; wherein, in the case that the threaded axis of the stepped internal thread coincides with the threaded axis of the threaded segment TS1: the tooth side profile line TS1-1 can completely contain the first tooth side profile line of the maximum solid tooth profile of the stepped internal thread, and at the same time, the tooth side profile line TS1-2 completely contains the second tooth side profile line of the maximum solid tooth profile of the stepped internal thread, and at the same time, the tooth side profile line TS1-4 partially coincides with the fifth tooth side profile line of the maximum solid tooth profile of the stepped internal thread, and at the same time, the tooth bottom profile line TS1-5 has a first preset distance from the sixth tooth top profile line of the maximum solid tooth profile of the stepped internal thread.

3. The stepped internal thread measuring tool according to claim 2, characterized in that the profile line of the design tooth profile of the threaded segment TS1 further comprises a tooth top profile line TS1-3, which is connected between the tooth side profile line TS1-2 and the tooth side profile line TS1-4, and the tooth top profile line TS1-3 is outside the tolerance band of the stepped internal thread.

4. The stepped internal thread measuring tool according to claim 1, characterized in that The profile line of the design tooth shape of the thread segment TS2 includes a flank profile line TS2-1, a flank profile line TS2-3, a crest profile line TS2-2 and a root profile line TS2-4; wherein, in the case that the thread axis of the internal stepped thread and the thread segment TS2 coincide: the flank profile line TS2-1 can completely contain the third flank profile line of the maximum solid tooth shape of the internal stepped thread, and at the same time the flank profile line TS2-3 completely contains the fifth flank profile line of the maximum solid tooth shape of the internal stepped thread, and at the same time the crest profile line TS2-2 is outside the tolerance band of the internal stepped thread, and at the same time the root profile line TS2-4 has a second preset distance from the sixth crest profile line of the maximum solid tooth shape of the internal stepped thread.

5. The internal stepped thread measuring tool according to claim 1, wherein, The profile line of the design tooth shape of the thread segment ZS1 includes a flank profile line ZS1-1, a flank profile line ZS1-3, a crest profile line ZS1-2 and a root profile line ZS1-4; wherein, in the case that the thread axis of the internal stepped thread and the thread segment ZS1 coincide: the flank profile line ZS1-1 can partially coincide with the first flank profile line of the minimum solid tooth shape of the internal stepped thread, and at the same time the flank profile line ZS1-3 partially coincides with the fifth flank profile line of the minimum solid tooth shape of the internal stepped thread, and at the same time the crest profile line ZS1-2 does not intersect the second flank profile line of the minimum solid tooth shape of the internal stepped thread, and at the same time the crest profile line ZS1-2 also does not intersect the second flank profile line of the maximum solid tooth shape of the internal stepped thread, and at the same time the root profile line ZS1-4 has a third preset distance from the sixth crest profile line of the maximum solid tooth shape of the internal stepped thread.

6. The internal stepped thread measuring tool according to claim 1, wherein, The profile line of the design tooth shape of the thread segment ZS2 includes a flank profile line ZS2-1, a flank profile line ZS2-2, a flank profile line ZS2-4 and a root profile line ZS2-5; wherein, in the case that the thread axis of the internal stepped thread and the thread segment ZS2 coincide: the flank profile line ZS2-2 can partially coincide with the second flank profile line of the minimum solid tooth shape of the internal stepped thread, and at the same time the flank profile line ZS2-4 partially coincides with the fifth flank profile line of the minimum solid tooth shape of the internal stepped thread, and at the same time the flank profile line ZS2-1 is outside the tolerance band of the internal stepped thread, and at the same time the distance between the flank profile line ZS2-1 and the first flank profile line of the maximum solid tooth shape of the internal stepped thread in the direction of the thread axis is greater than the width of the tolerance band of the internal stepped thread in the direction of the thread axis, and at the same time the root profile line ZS2-5 has a fourth preset distance from the sixth crest profile line of the maximum solid tooth shape of the internal stepped thread.

7. The internal stepped thread measuring tool according to claim 6, wherein, The profile line of the design tooth shape of the thread segment ZS2 further comprises a crest profile line ZS2-3, which is connected between the flank profile line ZS2-2 and the flank profile line ZS2-4.

8. The internal step thread measuring tool according to claim 1, wherein, The profile line of the design tooth shape of the thread segment ZS3 comprises a flank profile line ZS3-1, a flank profile line ZS3-3, a crest profile line ZS3-2 and a root profile line ZS3-4; wherein, in the case that the thread axis of the internal step thread and the thread segment ZS3 coincide: the flank profile line ZS3-1 can completely contain the third flank profile line of the minimum solid tooth shape of the internal step thread, and at the same time the flank profile line ZS3-3 completely contains the fifth flank profile line of the minimum solid tooth shape of the internal step thread, and at the same time the root profile line ZS3-4 has a fifth preset distance with the sixth crest profile line of the maximum solid tooth shape of the internal step thread.

9. A method of measuring a plug gage, comprising: The internal step thread measuring method is applied to the internal step thread measuring tool according to any one of claims 1-8, and the internal step thread measuring method comprises: The through-end plug gauge and the dead-end plug gauge are respectively screwed with the internal step thread; When the two thread segments of the through-end plug gauge can be screwed into the internal step thread respectively, and the three thread segments of the dead-end plug gauge cannot be screwed into the internal step thread, it can be determined that the actual size of the internal step thread is within the allowable tolerance range.

10. The pin thread measurement method of claim 9 wherein, The internal step thread measuring method further comprises: When any one thread segment of the through-end plug gauge cannot be screwed into the internal step thread, or any one thread segment of the dead-end plug gauge can be screwed into the internal step thread, it can be determined that the actual size of the internal step thread is not within the allowable tolerance range.

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