CN115615290A - Device and method for detecting pitch diameter of internal thread - Google Patents

Abstract

The disclosure provides a detection device and a detection method for the pitch diameter of an internal thread, which belong to the technical field of measurement. The detection device includes an adjustment structure and a detection structure; the adjustment structure includes a fixed sleeve, a slide bar, a locking assembly and a base, and the first end of the slide bar is coaxially and movably inserted into the first end of the fixed sleeve, and the lock The tightening component is sleeved outside the fixing sleeve and the sliding rod, and is used to lock the sliding rod in the fixing sleeve. The base is connected with the second end of the fixing sleeve, and the base is used to connect with the small-diameter cylindrical surface of the internal thread to be tested. Fitting; the detection structure includes a detection head and a screw micrometer, the detection head is connected to the screw micrometer, and the screw micrometer is connected to the second end of the slide rod, and the detection head is used to fit the tooth groove of the internal thread , and the line where the detection head and the fixed sleeve are located is perpendicular to the axis of the internal thread. The present disclosure can detect the pitch diameter of internal threads of different tooth types, pitches and thread specifications through the detection device.

Description

Device and method for detecting pitch diameter of internal thread

technical field

The disclosure belongs to the technical field of measurement, and in particular relates to a detection device and a detection method for the pitch diameter of an internal thread.

Background technique

The pitch diameter of the thread is the diameter of an imaginary cylinder whose generatrix passes through the groove (tooth groove) on the tooth profile in the axial section of the thread and has the same width as the protrusion. The pitch diameter of the thread is a very important value, which has a great influence on the assembly quality of the workpiece.

In the related art, for the internal thread, the detection and measurement device for the pitch diameter of the internal thread includes an internal thread micrometer and two measuring contacts connected with the internal thread micrometer, wherein one measuring contact is a cone, and one measuring The contacts have V-grooves. In the actual measurement, it is first necessary to select the corresponding measuring contact and internal thread micrometer according to the different tooth grooves and pitches of the internal thread. Then, connect the selected two measuring contacts with the two ends of the internal thread micrometer, and clamp one of the selected two measuring contacts (the measuring contact with a V-shaped groove) to the tooth profile of the internal thread In the groove, the other one (cone-shaped measuring contact) is set on the conical surface opposite to the tooth-shaped groove, and the reading corresponding to the internal thread micrometer is the actual size of the pitch diameter of the internal thread.

Since there are many tooth types and pitch combinations of internal threads, to meet the needs of the product, it is necessary to configure a lot of measuring contacts and internal thread micrometers of different specifications, and the common measuring contacts on the market are all metric ordinary threads (triangular Threads, etc.), while there are very few measuring contacts suitable for special tooth-shaped threads, such as sawtooth threads and trapezoidal threads, resulting in limited use of the above devices and cannot be widely used.

Contents of the invention

Embodiments of the present disclosure provide a detection device and detection method for the pitch diameter of internal threads, which can detect the pitch diameters of internal threads with different tooth profiles, pitches and thread specifications. Described technical scheme is as follows:

An embodiment of the present disclosure provides a detection device for the pitch diameter of an internal thread, the detection device includes an adjustment structure and a detection structure; the adjustment structure includes a fixing sleeve, a slide rod, a locking assembly and a base, and the slide rod The first end is coaxially and movably inserted into the first end of the fixing sleeve, and the locking assembly is sleeved outside the fixing sleeve and the sliding rod, for locking the sliding rod Locked in the fixed sleeve, the base is connected to the second end of the fixed sleeve, and the base is used to fit the small-diameter cylindrical surface of the internal thread to be tested; the detection structure includes a detection head and a screw micrometer, the detection head is connected to the screw micrometer, and the screw micrometer is connected to the second end of the slide rod, and the detection head is used to connect with the tooth of the internal thread The groove fits together, and the line where the detection head and the fixed sleeve are located is perpendicular to the axis of the internal thread.

In yet another implementation of the present disclosure, the base includes a wedge block and a screw sleeve, the wedge block is a triangular block structure, one end of the screw sleeve is connected to the bottom surface of the wedge block, and the wedge block The triangular wedge-shaped top edge of the wedge-shaped block is used to fit the small-diameter cylindrical surface of the internal thread, the triangular wedge-shaped top edge of the wedge-shaped block is coplanar and perpendicular to the axis of the screw sleeve, and the bottom surface of the wedge-shaped block is in line with the The triangular wedge-shaped top edge of the wedge-shaped block is arranged oppositely; the other end of the screw sleeve is connected with the fixed sleeve.

In yet another implementation of the present disclosure, the locking assembly includes a fixed collar, a sliding collar, and an elastic member; the first end of the fixed collar is connected to the first end of the fixed sleeve, and the The fixed collar is sleeved on the outside of the slide bar and fitted to the outer wall of the slide bar, and the outer diameter of the fixed collar is along the direction from the second end of the fixed collar to the fixed collar The direction of the middle part gradually decreases, and a plurality of bar-shaped grooves are provided between the second end of the fixed collar and the middle part of the fixed collar, one end of the bar-shaped groove is open and is located in the fixed collar. The second end of the collar; the sliding collar is slidably sleeved on the second end of the fixed collar, and an accommodating cavity is formed between the sliding collar and the fixed collar, and the elastic member Located in the accommodating cavity and arranged along the axial direction of the slide bar, the two ends of the elastic member respectively abut against the outer wall of the fixed collar and the inner wall of the sliding collar.

In yet another implementation manner of the present disclosure, the fixing collar includes a first ring body and a second ring body, the first end of the first ring body is sleeved on the first end of the second ring body Outside, the sliding collar is slidably sleeved outside the first ring body and the second ring body, and the outer wall of the second ring body from the middle part to the second end is a conical surface; the outer wall of the first ring body The second end is connected to the fixed sleeve, the elastic member is sleeved outside the second ring, and the first end surface of the first ring, the inner wall of the sliding collar and the second ring An accommodating cavity is formed between the outer walls of the second ring body, the bar-shaped groove is located on the outer wall of the second ring body, and the opening is located at the second end of the second ring body.

In yet another implementation manner of the present disclosure, the inner wall of the sliding collar has a first limiting inner flange, and the outer wall of the second end of the second ring body is provided with a first limiting inner flange. Limiting hooks that match the edges.

In yet another implementation manner of the present disclosure, the inner wall of the sliding collar has a second limiting inner flange, and the second limiting inner flange is spaced apart from the first limiting inner flange, and The second limiting inner flange is located between the first limiting inner flange and the first ring body, and the second end of the elastic member abuts against the second limiting inner flange.

In yet another implementation of the present disclosure, the detection head includes a connecting rod and a hemispherical head, one end of the connecting rod is connected to the hemispherical head, and the other end of the connecting rod is connected to the screw micrometer .

In yet another implementation manner of the present disclosure, the middle part of the connecting rod has an outer flange, and the outer flange abuts against the end of the screw micrometer.

In yet another implementation manner of the present disclosure, a detection method for pitch diameter of an internal thread is also provided, the detection method is based on the detection device described above, and the detection method includes: measuring the screw in the detection device Reset the microcomputer to zero; adjust the position of the sliding rod in the detection device relative to the fixed sleeve so that the total length of the detection device is less than the small diameter of the internal thread, record the current total length L ₁ of the detection device; The detection device is placed in the internal thread, one side of the base is attached to the cylindrical surface of the small diameter of the internal thread, and the screw micrometer in the detection device is adjusted so that the detection head penetrates into the In the tooth-shaped groove of the internal thread and the detection head is attached to both sides of the tooth-shaped groove, and the maximum reading of the spiral micrometer is L ₂ ; according to the L ₁ , L ₂ and the detection The diameter of the head and the parameters of the internal thread obtain the pitch diameter of the internal thread.

In another implementation manner of the present disclosure, the pitch diameter of the internal thread is obtained according to the L ₁ , L ₂ , the diameter of the detection head and the parameters of the internal thread, including:

The pitch diameter of the internal thread satisfies the following formula:

D ₂ =2(L ₁ +L ₂ )-D ₁ -K ₁ d ₀ -K ₂ p;

Among them, D ₂ is the middle diameter of the internal thread; D ₁ is the small diameter of the internal thread; d ₀ is the outer diameter of the detection head; p is the pitch of the internal thread; K ₁ and K ₂ are coefficients.

The beneficial effects brought by the technical solutions provided by the embodiments of the present disclosure are:

The detection device for the pitch diameter of the internal thread provided by the embodiment of the present disclosure can adjust the length of the adjustment structure by moving the slide bar relative to the fixed sleeve when detecting the pitch diameter of the internal thread, and at the same time, the length of the adjustment structure can be adjusted by the locking assembly The sliding rod is locked on the fixed sleeve to fix the length of the adjustment structure.

Moreover, since the detection device also includes a detection head and a screw micrometer, the detection head can be fitted together with the tooth-shaped groove of the internal thread, and the base can be fitted with the small-diameter cylindrical surface of the internal thread during detection. Then, by reading the value of the screw micrometer and combining the length of the detection device, the pitch diameter of the internal thread is calculated. When the detection device detects various types of internal threads, it only needs to match the detection head with the tooth groove of the internal thread, and fit the base with the small-diameter cylindrical surface of the internal thread, so as to avoid the need for different types of internal threads. A plurality of measuring contacts of different types and specifications are arranged, which greatly improves the applicability of the detection device.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is a schematic diagram of basic parameters of an internal thread provided by an embodiment of the present disclosure;

Fig. 2 is a schematic diagram of several common internal threads provided by embodiments of the present disclosure;

Fig. 3 is a schematic structural diagram of a detection device provided by an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of a base provided by an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of a locking structure provided by an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of a detection head provided by an embodiment of the present disclosure;

FIG. 7 is a flow chart of a method for detecting the pitch diameter of an internal thread provided by an embodiment of the present disclosure;

Fig. 8 is a diagram of the use state of the detection device provided by the embodiment of the present disclosure.

The meanings of the symbols in the figure are as follows:

1. Adjustment structure; 11. Fixed sleeve; 12. Slide bar; 13. Locking assembly; 131. Fixed collar; 1311. First ring body; 1312. Second ring body; 1313. Limit hook; 132. Sliding collar; 1321, first limiting inner flange; 1322, second limiting inner flange; 134, elastic member; 130, accommodating cavity; 1310, strip groove; 14, base; 141, wedge block; 142, screw sleeve;

2. Detection structure; 21. Detection head; 211. Connecting rod; 2111. Outer flange; 212. Hemispherical head; 22. Spiral micrometer.

detailed description

In order to make the purpose, technical solution and advantages of the present disclosure clearer, the implementation manners of the present disclosure will be further described in detail below in conjunction with the accompanying drawings.

In order to clearly illustrate the detection device for the pitch diameter of the internal thread provided by the embodiment of the present disclosure, the relevant parameters of the internal thread are firstly introduced here.

Major diameter (bottom diameter) of the internal thread: the diameter of the imaginary cylinder that coincides with the bottom of the internal thread. In general, the nominal diameter of the thread is the major diameter, as shown in D ₄ in Figure 1.

Minor diameter (top diameter) of the internal thread: the diameter of an imaginary cylinder that coincides with the crest of the internal thread, such as D _{1 in Figure 1} .

The pitch diameter of the internal thread, the diameter of an imaginary cylinder whose generatrix passes through the protrusion and the groove on the tooth form with equal width, as shown in D ₂ in Figure 1.

The pitch of the internal thread, the axial distance between adjacent teeth corresponding to two points on the median line, as shown in p in Figure 1.

The profile angle of the internal thread is the angle α between two adjacent tooth flanks on the thread profile groove, and the profile half angle is α/2 (see Figure 2 a, c).

The flank angle of the internal thread is the angle between the upper flank of the thread groove and the vertical line of the thread axis, such as α ₁ , α ₂ , and the tooth profile angle is (α ₁ +α ₂ ).

In addition, internal threads can be divided into triangular threads (ordinary threads), rectangular threads, trapezoidal threads, sawtooth threads and other special-shaped threads according to their cross-sectional shape (tooth groove). See a, b, c, and d in Figure 2.

An embodiment of the present disclosure provides a detection device for the pitch diameter of an internal thread. As shown in FIG. 3 , the detection device includes an adjustment structure 1 and a detection structure 2 . The adjustment structure 1 includes a fixing sleeve 11 , a sliding rod 12 , a locking assembly 13 and a base 14 . The first end of the sliding rod 12 is coaxially and movably inserted into the first end of the fixing sleeve 11, and the locking assembly 13 is sleeved outside the fixing sleeve 11 and the sliding rod 12 for locking the sliding rod 12. In the fixed sleeve 11. The base 14 is connected to the second end of the fixing sleeve 11, and the base 14 is used to fit the small-diameter cylindrical surface of the internal thread to be tested. The detection structure 2 includes a detection head 21 and a screw micrometer 22, the detection head 21 is connected to the screw micrometer 22, and the screw micrometer 22 is connected to the second end of the slide rod 12, and the detection head 21 is used for connecting with the internal thread. The tooth-shaped grooves fit together, and the straight line where the detection head 21 and the fixed sleeve 11 are located is perpendicular to the axis of the internal thread.

The detection device for the pitch diameter of the internal thread provided by the embodiment of the present disclosure can adjust the length of the adjustment structure 1 through the movement of the slide bar 12 relative to the fixed sleeve 11 when detecting the pitch diameter of the internal thread, and at the same time, it can be adjusted by the lock The tightening assembly 13 locks the sliding rod 12 on the fixing sleeve 11 to fix the length of the adjusting structure 1 .

And, because this detection device also comprises detection head 21 and spiral micrometer 22, so just can when detection, the detection head 21 is bonded together with the profile groove of internal thread, and base 14 is bonded with the small-diameter cylindrical surface of internal thread. Together, and then by reading the value of the screw micrometer 22 and combining the length of the detection device, the pitch diameter of the internal thread is calculated. When the detection device detects various types of internal threads, it only needs the detection head 21 to cooperate with the tooth-shaped groove of the internal thread, and the base 14 to fit the small-diameter cylindrical surface of the internal thread, so as to avoid different types of internal threads. However, a plurality of measuring contacts of different types and specifications need to be provided, which greatly improves the applicability of the detection device.

FIG. 4 is a schematic structural diagram of a base provided by an embodiment of the present disclosure. Referring to FIG. 4 , for example, the base 14 includes a wedge 141 and a screw sleeve 142 . The wedge block 141 is a triangular block structure.

One end of the screw sleeve 142 is connected to the bottom surface of the wedge block 141 , and the triangular wedge-shaped top edge of the wedge block 141 is used to fit the small-diameter cylindrical surface of the internal thread. The triangular wedge-shaped top of the wedge-shaped block 141 is coplanar and perpendicular to the axis of the screw sleeve 142 , and the bottom surface of the wedge-shaped block 141 is opposite to the triangular wedge-shaped top of the wedge-shaped block 141 . The other end of the screw sleeve 142 is connected with the fixed sleeve 11 .

In the above implementation manner, the base 14 is configured as a wedge block 141 and a screw sleeve 142, which can be connected to the fixed sleeve 11 through the screw sleeve 142, and at the same time, the wedge block 141 is attached to the small-diameter cylindrical surface of the internal thread.

In addition, since the small-diameter cylindrical surface of the internal thread is an arc-shaped surface, in order to enable the wedge-shaped block 141 to achieve a good fit with the small-diameter cylindrical surface of the internal thread, the wedge-shaped block 141 is set as a triangular block structure, so that The triangular wedge-shaped top edge of the wedge-shaped block 141 can be made to be tangent to the small-diameter cylindrical surface of the internal thread, thereby improving the fit between the two.

Exemplarily, the threaded sleeve 142 is threaded on the fixing sleeve 11 , so that the two can be easily disassembled and connected.

FIG. 5 is a schematic structural diagram of a locking structure provided by an embodiment of the present disclosure. Referring to FIG. 5 , optionally, the locking assembly 13 includes a fixed collar 131 , a sliding collar 132 and an elastic member 134 . The first end of the fixed collar 131 is connected to the first end of the fixed sleeve 11, the fixed collar 131 is set outside the slide bar 12, and is attached to the outer wall of the slide bar 12, and the outer diameter of the fixed collar 131 is along the The direction from the second end of the fixing collar 131 to the middle of the fixing collar 131 gradually decreases. A plurality of bar-shaped grooves 1310 are provided between the second end of the fixing collar 131 and the middle part of the fixing collar 131 , and one end of the bar-shaped grooves 1310 is open and located at the second end of the fixing collar 131

The sliding collar 132 is slidably sleeved on the second end of the fixed collar 131 to form an accommodating cavity 130 between the outer sliding collar 132 and the fixed collar 131, the elastic member 134 is located in the accommodating cavity 130, and along the sliding rod 12 is arranged in the axial direction, and the two ends of the elastic member 134 respectively abut against the outer wall of the fixed collar 131 and the inner wall of the sliding collar 132 .

In the above implementation manner, the locking assembly 13 is set as a fixed collar 131, a sliding collar 132 and an elastic member 134, so that the fixing collar 131 can be connected with the fixing sleeve 11 so as to connect the locking assembly 13 On the fixed sleeve 11. At the same time, the elastic member 134 can be used to make the sliding collar 132 as far away from the first end of the fixed collar 131 as possible when no external force is applied, so that the sliding collar 132 can be placed on the first end of the fixed collar 131 as much as possible. Outside the two ends. Moreover, since the outer diameter of the fixed collar 131 changes gradually and is provided with a plurality of bar-shaped grooves 1310, the fixed collar 131 can expand and contract in the radial direction under the clamping of the sliding collar 132, thereby limiting the fixed collar. The inner diameter of the second end of the ring 131 enables clamping between the fixed collar 131 and the slide rod 12 .

The reason why the sliding collar 132 can move is to facilitate flexible adjustment of the position of the sliding collar 132 on the fixed collar 131 to unlock the locking between the fixed collar 131 and the slide bar 12 .

That is to say, when there is no external force, due to the effect of the elastic member 134, the sliding collar 132 is stably sleeved on the second end of the fixing collar 131, so as to clamp the second end of the fixing collar 131 and slide the rod 12 is limited in the second end of the fixing collar 131 , so as to realize the connection and fixing between the sliding rod 12 and the fixing sleeve 11 . And when it is necessary to adjust the position of the sliding rod 12 relative to the fixed sleeve 11, the sliding collar 132 can be moved by hand, so that the sliding collar 132 moves toward the first end of the fixing collar 131, thereby unlocking the position of the sliding bar 12 relative to the fixed sleeve. To connect the cylinders 11, adjust the position of the slide rod 12, and then loosen the sliding collar 132, so that the sliding collar 132 clamps the second end of the fixed collar 131 again under the action of the elastic member 134, thereby realizing again The clamping between the collar 131 and the slide bar 12 is fixed.

Continuing to refer to FIG. 5 , optionally, the fixing collar 131 includes a first ring body 1311 and a second ring body 1312 , the first end of the first ring body 1311 is sleeved outside the first end of the second ring body 1312 , and the sliding The collar 132 is slidably sleeved on the first ring body 1311 and the second ring body 1312 , and the outer wall of the second ring body 1312 from the middle part to the second end is a conical surface.

The second end of the first ring body 1311 is connected to the fixed sleeve 11, the elastic member 134 is sleeved on the outside of the second ring body 1312, and the first end surface of the first ring body 1311, the inner wall of the sliding collar 132 and the second ring body An accommodating cavity 130 is formed between the outer walls of 1312 , the bar-shaped groove 1310 is located on the outer wall of the second ring body 1312 , and the opening is located at the second end of the second ring body 1312 .

In the above implementation manner, the fixing collar 131 is configured as the first ring body 1311 and the second ring body 1312 , so that the accommodating cavity 130 can be conveniently formed to provide the installation base for the elastic member 134 . At the same time, it facilitates the connection between the fixing sleeve 11 and the sliding rod 12 .

Exemplarily, the first ring body 1311 is threaded on the outside of the second ring body 1312 , and adjusting the screw-in length will change the size of the accommodating cavity 130 , thereby adjusting the pre-tightening force of the elastic member 134 .

Optionally, the inner wall of the sliding collar 132 has a first limiting inner flange 1321 , and the outer wall of the second end of the second ring body 1312 is provided with a limiting hook 1313 matched with the first limiting inner flange 1321 .

In the above implementation manner, the setting of the first limiting inner flange 1321 and the limiting hook 1313 can enable the sliding collar 132 to be stably clamped outside the second ring body 1312 under the action of the elastic member 134, so that the second The ring body 1312 is tightly sleeved on the outside of the sliding rod 12 .

Exemplarily, the above-mentioned cooperation between the first limiting inner flange 1321 and the limiting hook 1313 means that when the sliding bar 12 is separated from the fixing sleeve 11 and the locking assembly 13, under the action of the elastic member 134, the first A position-limiting inner flange 1321 always abuts against the position-limiting hook 1313 without breaking away from the second ring body 1312 .

Optionally, the inner wall of the sliding collar 132 has a second limiting inner flange 1322, the second limiting inner flange 1322 is spaced apart from the first limiting inner flange 1321, and the second limiting inner flange 1322 is located Between the first limiting inner flange 1321 and the first ring body 1311 , the second end of the elastic member 134 abuts against the second limiting inner flange 1322 .

In the above implementation manner, the arrangement of the second limiting inner flange 1322 can conveniently clamp the elastic member 134 in the accommodating cavity 130 .

FIG. 6 is a schematic structural view of the detection head provided by the embodiment of the present disclosure. With reference to FIG. 6 , optionally, the detection head 21 includes a connecting rod 211 and a hemispherical head 212, one end of the connecting rod 211 is connected to the hemispherical head 212, and the connecting rod 211 The other end is connected with the screw micrometer 22 .

In the above implementation, the detection head 21 is set as a connecting rod 211 and a hemispherical head 212, so that the hemispherical head 212 and the screw micrometer 22 can be connected together through the connecting rod 211, and at the same time, the hemispherical head 212 can be stably positioned at It fits in the tooth groove of the internal thread to be tested to facilitate detection.

Of course, setting the detection head 21 as a hemispherical head 212 is also for the convenience of subsequent calculation of coefficients K ₁ and K ₂ (which will be introduced later) during detection.

Exemplarily, the connecting rod 211 is screwed together with the screw micrometer 22 . This facilitates the disassembly connection between the two. The hemispherical head 212 and the connecting rod 211 can be integrally formed as a structural member, which is convenient for processing and manufacturing.

Exemplarily, the middle part of the connecting rod 211 has an outer flange 2111 . The outer flange 2111 abuts against the end of the screw micrometer 22 .

In this way, the connecting rod 211 can be positioned at one end of the screw micrometer 22 through the outer flange.

On the other hand, the present disclosure is an embodiment that also provides a detection method for the pitch diameter of the internal thread, as shown in FIG. 7 , the detection method is based on the above-mentioned detection device, and the detection method includes:

S701: Reset the screw micrometer in the detection device to zero.

S702: Adjust the position of the sliding rod in the detection device relative to the fixed sleeve so that the total length of the detection device is smaller than the minor diameter of the internal thread, and record the current total length L ₁ of the detection device.

For example, the position of the slide bar relative to the fixed sleeve can be adjusted by adjusting the locking assembly in the detection device, so that the total length of the detection device is slightly smaller than the small diameter of the internal thread, and the current position of the detection device is measured and recorded using a caliper or other utensils. total length.

The total length of the detection device mentioned above is slightly smaller than the minor diameter of the internal thread, and the difference between the total length of the detection device and the minor diameter of the internal thread may be 1-10 mm.

S703: Place the detection device in the inner hole of the internal thread, fit one side of the base with the cylindrical surface of the small diameter of the internal thread, adjust the screw micrometer in the detection device, so that the detection head goes deep into the tooth groove of the internal thread and It fits both sides of the tooth groove, and the maximum reading of the screw micrometer is L ₂ .

In the above step S703, when one side of the base is attached to the small-diameter cylindrical surface of the internal thread, the triangular wedge-shaped top edge of the base is actually attached to the small-diameter cylindrical surface of the internal thread. At the same time, by adjusting the spiral micrometer in the detection device Make the spherical surface of the hemispherical head of the detection head go deep into the tooth groove of the internal thread and fit the spherical surface to both sides of the tooth groove, and then read the maximum reading of the spiral micrometer.

By adjusting the screw micrometer above, the total length of the detection device can be further adjusted so that the detection head can fully fit the groove surface of the tooth groove.

S704: Obtain the pitch diameter of the internal thread according to L ₁ , L ₂ , the diameter of the detection head, and the parameters of the internal thread.

The above method has the same beneficial effects as the detection device mentioned above, and will not be repeated here.

In this embodiment, before step 701, it is necessary to select a suitable detection head according to the relevant parameters of the internal thread, so that the detection head can be located in the tooth groove of the internal thread to be detected.

Exemplarily, according to the profile angle and pitch of the internal thread to be tested, the _optimum outer diameter d of the required detection head is calculated by the formula, and the actual detection head is selected. The outer diameter of the detection head should be as close as possible to the minimum The calculated value of the _best outer diameter d.

The calculation formula of the _optimal outer diameter d of the detection head can refer to the calculation formulas corresponding to different types of internal threads in the industry, and will not be repeated here.

After selecting the detection head, connect the corresponding detection head to the detection device for the detection of the pitch diameter of the internal thread.

The above method has the same beneficial effects as the detection device mentioned above, and will not be repeated here.

Optionally, step S704 may be implemented in the following manner:

Exemplarily, the pitch diameter of the internal thread satisfies the following formula:

D ₂ =2(L ₁ +L ₂ )-D ₁ -K ₁ d ₀ -K ₂ p; (1)

Among them, D ₂ is the middle diameter of the internal thread; D ₁ is the small diameter of the internal thread; d ₀ is the outer diameter of the detection head; p is the pitch of the internal thread; K ₁ and K ₂ are coefficients.

The above formula (1) can be derived according to the following formula (2).

2M=2×(L ₁ +L ₂ )=D ₂ +D ₁ +K ₁ ×d ₀ +K ₂ ×p; (2)

Among them, M can be seen as shown in Figure 8, which is the total length of the detection device when the detection device is attached to the internal thread; D2 is the middle diameter _of the internal thread; D1 is the _minor diameter of the internal thread _; d0 is the outer diameter of the detection head Diameter; p is the pitch of internal thread; K ₁ and K ₂ are coefficients.

In addition, combined with Figure 8, we can know:

Where x can be as shown in Fig. 8, which represents the distance from the vertex of the spherical surface of the detection head to the pitch diameter of the internal thread. In order to further generalize the formula (3), the relationship between x and d ₀ and the pitch p of the internal thread can be established, so that the formula (1) can be obtained.

In addition, due to the different types of internal threads, the calculation methods of K1 and K2 in the above formula ( ₁ ) or ( ₂ ) will be different.

Generally speaking, when the profile groove of the internal thread section is an asymmetrical figure, the following formulas (4) and (5) can be used to calculate K ₁ and K ₂ respectively. When the profile groove of the internal thread section is a symmetrical figure, the following formulas (6) and (7) can be used to calculate K ₁ and K ₂ respectively.

Among them, α ₁ and α ₂ are the flank angles of the tooth groove of the internal thread.

Among them, α is the tooth angle of the tooth groove of the internal thread.

The above calculation formulas (4)-(7) can all be derived according to relevant mathematical formulas, and will not be repeated here.

Below in conjunction with specific example and accompanying drawing 8 will further illustrate above detection method:

For example, taking the internal thread of the zigzag thread (3°, 30°) as an example, the pitch diameter of the internal thread can be detected by the following steps:

First, according to the tooth profile angle and pitch of the internal thread to be tested, calculate the optimal outer diameter of the required detection head through the formula, and select the actual detection head according to the optimal outer diameter, so that the outer diameter of the detection head satisfies the following formula:

Among them, d ₀ is the outer diameter of the actual detection head; dbest is the _best outer diameter of the detection head; α ₁ and α ₂ are the flank angles of the internal thread; p is the pitch of the internal thread.

Then, reset the screw micrometer to zero, move the sliding collar 132, and adjust the extension length of the slide rod 12, so that the total length of the detection device is slightly smaller than the minor diameter D1 _of the internal thread to be measured. At this time, record the current detection device. The total length is L ₁ .

Next, the triangular wedge-shaped top edge of the base of the detection device is attached to the small-diameter cylindrical surface of the internal thread, and the triangular wedge-shaped top edge is kept parallel to the axis of the small diameter of the internal thread. Slowly adjust the screw micrometer, and insert the detection head into the tooth groove of the internal thread until the spherical surface of the detection head touches both sides of the tooth groove of the internal thread, and the reading of the spiral micrometer is the largest Time (indicating that the elongation distance of the spiral micrometer is the maximum at this time), record the reading L ₂ of the spiral micrometer.

S4. Calculate the pitch diameter of the internal thread according to the aforementioned formula (1).

Among them, K ₁ and K ₂ can be obtained according to formulas (4) and (5).

For another example, taking ordinary internal thread (60° triangular internal thread) as an example, the pitch diameter of internal thread can be detected by the following steps:

The difference from the above example is that the calculation formula of the _best d is different, and the following formula is used:

Among them, d ₀ is the outer diameter of the actually selected detection head; d _best is the best outer diameter of the detection head; α/2 is the half-angle of the tooth profile of the internal thread; p is the pitch of the internal thread.

And K ₁ and K ₂ can be obtained according to formulas (6) and (7).

The above are only optional embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure Inside.

Claims (10)

1. The detection device for the pitch diameter of the internal thread is characterized by comprising an adjusting structure (1) and a detecting structure (2);

the adjusting structure (1) comprises a fixed sleeve (11), a sliding rod (12), a locking component (13) and a base (14), wherein the first end of the sliding rod (12) is coaxially and movably inserted into the first end of the fixed sleeve (11), the locking component (13) is sleeved outside the fixed sleeve (11) and the sliding rod (12) and used for locking the sliding rod (12) in the fixed sleeve (11), the base (14) is connected with the second end of the fixed sleeve (11), and the base (14) is used for being attached to a small-diameter cylindrical surface of an internal thread to be detected;

detect structure (2) including detecting head (21) and micrometer caliper (22), detect head (21) with micrometer caliper (22) are connected, just micrometer caliper (22) with the second end of slide bar (12) is connected, detect head (21) be used for with the laminating of internal screw thread tooth form groove, just detect head (21) and the straight line at fixed sleeve (11) place with the internal screw thread axis is perpendicular.

2. The detection device according to claim 1, characterized in that said seat (14) comprises a wedge-shaped block (141) and a threaded sleeve (142);

the wedge block (141) is of a triangular block-shaped structure, one end of the screw sleeve (142) is connected with the bottom surface of the wedge block (141), the triangular wedge-shaped top edge of the wedge block (141) is used for being attached to the small-diameter cylindrical surface of the internal thread, the triangular wedge-shaped top edge of the wedge block (141) is coplanar with and perpendicular to the axis of the screw sleeve (142), and the bottom surface of the wedge block (141) is arranged opposite to the triangular wedge-shaped top edge of the wedge block (141);

the other end of the threaded sleeve (142) is connected with the fixed sleeve (11).

3. The detection device according to claim 1, characterized in that the locking assembly (13) comprises a fixed collar (131), a sliding collar (132) and an elastic member (134);

the first end of the fixed sleeve ring (131) is connected with the first end of the fixed sleeve (11), the fixed sleeve ring (131) is sleeved outside the sliding rod (12) and attached to the outer wall of the sliding rod (12), the outer diameter of the fixed sleeve ring (131) is gradually reduced along the direction from the second end of the fixed sleeve ring (131) to the middle of the fixed sleeve ring (131), a plurality of strip-shaped grooves (1310) are formed between the second end of the fixed sleeve ring (131) and the middle of the fixed sleeve ring (131), and one ends of the strip-shaped grooves (1310) are open and are located at the second end of the fixed sleeve ring (131);

the sliding collar (132) is slidably sleeved outside the second end of the fixed collar (131), an accommodating cavity (130) is formed between the sliding collar (132) and the fixed collar (131), the elastic piece (134) is located in the accommodating cavity (130) and arranged along the axial direction of the sliding rod (12), and two ends of the elastic piece (134) are respectively abutted to the outer wall of the fixed collar (131) and the inner wall of the sliding collar (132).

4. A detection device according to claim 3, characterized in that the fixing collar (131) comprises a first ring body (1311) and a second ring body (1312),

the first end of the first ring body (1311) is sleeved outside the first end of the second ring body (1312), the sliding sleeve ring (132) is slidably sleeved outside the first ring body (1311) and the second ring body (1312), and the outer wall of the second ring body (1312) from the middle to the second end is a conical surface;

the second end of the first ring body (1311) is connected with the fixing sleeve (11), the elastic piece (134) is sleeved outside the second ring body (1312), an accommodating cavity (130) is formed among the first end face of the first ring body (1311), the inner wall of the sliding sleeve ring (132) and the outer wall of the second ring body (1312), the strip-shaped groove (1310) is located on the outer wall of the second ring body (1312), and the opening is located at the second end of the second ring body (1312).

5. The detection device according to claim 4, characterized in that the inner wall of the sliding collar (132) has a first inner limit flange (1321),

and a limiting hook (1313) matched with the first limiting inner flange (1321) is arranged on the outer wall of the second end of the second ring body (1312).

6. The detection device according to claim 5, characterized in that the inner wall of the sliding collar (132) has a second inner limit flange (1322), the second inner limit flange (1322) is spaced apart from the first inner limit flange (1321), the second inner limit flange (1322) is located between the first inner limit flange (1321) and the first ring body (1311), and the second end of the elastic member (134) abuts against the second inner limit flange (1322).

7. The device according to any one of claims 1 to 6, wherein the detection head (21) comprises a connecting rod (211) and a hemispherical head (212), one end of the connecting rod (211) is connected with the hemispherical head (212), and the other end of the connecting rod (211) is connected with the micrometer screw (22).

8. The device according to claim 7, characterized in that the middle of the connecting rod (211) has an external flange (2111), the external flange (2111) abutting the end of the micrometer screw (22).

9. A method for detecting the pitch diameter of an internal thread, which is based on the detection device of any one of claims 1 to 8, and comprises the following steps:

zeroing a micrometer screw in the detection device;

adjusting the position of the sliding rod in the detection device relative to the fixed sleeve to enable the total length of the detection device to be slightly smaller than the small diameter of the internal thread, and recording the current total length L of the detection device ₁ ；

Arranging the detection device in the internal thread, attaching one side of the base to the cylindrical surface with the small diameter of the internal thread, adjusting a screw micrometer in the detection device to enable the detection head to go deep into the tooth-shaped groove of the internal thread and attach the detection head to two sides of the tooth-shaped groove, and reading the maximum reading of the screw micrometer to be L ₂ ；

According to said L ₁ 、L ₂ And the diameter of the detection head and the parameters of the internal thread to obtain the pitch diameter of the internal thread.

10. The detection method according to claim 9, wherein said detecting is according to said L ₁ 、L ₂ And the diameter of the detection head and the parameters of the internal thread to obtain the pitch diameter of the internal thread, and the method comprises the following steps:

the pitch diameter of the internal thread satisfies the following formula:

D ₂ ＝2(L ₁ +L ₂ )-D ₁ -K ₁ d ₀ -K ₂ p；

wherein D is ₂ The pitch diameter of the internal thread; d ₁ Is the minor diameter of the internal thread; d ₀ For detecting the outer diameter of the head; p is the pitch of the internal thread; k is ₁ And K ₂ Are coefficients.

Images