Taper internal thread pitch diameter detection device

Abstract

The invention belongs to the technical field of thread pitch diameter detection, and relates to a taper internal thread pitch diameter detection device which comprises a measuring support, a ball head frame, a micrometer, an end face dial indicator, a measuring head assembly and a synchronous block. The measuring support serves as a carrier, the ball head frame is installed on the measuring support in a sliding mode, and a ball head makes contact with a thread profile to form an intermediate-diameter generatrix. The micrometer is used for measuring the distance between the threaded end face and the reference face. The end face dial indicator displays the displacement of the measuring head assembly. The measuring head assembly comprises a measuring rod, a mounting sleeve, a spring and a fixing cover, and ball measuring heads are arranged at the two ends of the measuring rod and connected with the thread pitch diameter line measuring point and the end face dial indicator respectively. The synchronous block converts the displacement of the measuring head assembly into the reading of the end face dial indicator. According to the device, the movable ball head is in contact with the thread profile, the micrometer and the end face dial indicator are combined for measurement, the pitch diameter of the taper thread is accurately measured, the structure is simple, operation is convenient, the measurement precision is high, the device is suitable for the internal thread pitch diameter detection occasion, and the problems existing in the internal thread pitch diameter detection technology are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thread pitch diameter detection and relates to a taper internal thread pitch diameter detection device. Background Art

[0002] At present, the detection means of internal thread pitch diameter mainly rely on the traditional tool of plug gauge. The detection principle of the plug gauge is to determine the size of the pitch diameter based on the flank angle accuracy of the thread. However, in actual applications, even a tiny error in the flank angle may have a significant impact on the detection accuracy of the pitch diameter. This impact makes the traditional plug gauge detection method unable to accurately measure the actual pitch diameter of the thread, but only obtain a pitch diameter value based on assumptions and approximations. This imaginary pitch diameter value often has a certain deviation from the actual thread pitch diameter, thus affecting the accuracy and reliability of the detection.

[0003] Abroad, although the detection technology of internal thread pitch diameter has developed, its basic principle is still similar to that of the plug gauge. Most of these technologies adopt the tooth profile contact method and simulate the shape of the thread by designing multi-lobe tooth profiles for detection. However, this multi-lobe tooth profile detection method also has the problem of not being able to accurately reflect the pitch diameter accuracy of the thread. The design, manufacture and calibration of the multi-lobe tooth profile are relatively complex, and it is easily affected by factors such as wear and deformation during use, thus further reducing the detection accuracy.

[0004] In order to improve the detection accuracy of thread pitch diameter, researchers have begun to explore new detection methods. Among them, the ball contact detection method has gradually attracted attention due to its unique advantages. This method measures the pitch diameter of the thread by using the contact between the ball head and the thread tooth profile surface. Since the ball head has a smooth surface and good adaptability, it can more accurately simulate the shape of the thread and measure its pitch diameter. This method has improved the detection accuracy of thread pitch diameter to a certain extent and provided new ideas for the development of thread detection technology.

[0005] However, although the ball head detection method has many advantages in thread pitch diameter detection, it still faces some problems in actual applications. For example, how to ensure the accurate contact between the ball head and the thread tooth profile surface is a key issue. Since the shapes and sizes of threads are diverse, it is necessary to design a ball head that can adapt to different thread shapes and ensure its full contact with the thread tooth profile surface. In addition, how to accurately measure the distance between the ball head and the pitch diameter generatrix of the thread is also a technical problem. The measurement of this distance requires high-precision measurement equipment and professional operation skills to ensure the accuracy and reliability of the measurement.

[0006] In summary, there are still many problems and challenges in the current detection technology of the pitch diameter of internal threads. Although the traditional plug gauge detection method is simple and easy to implement, its detection accuracy is limited by the flank angle error; while the multi-lobe thread profile detection method abroad has problems such as complex manufacturing and calibration, and is easily affected by wear and deformation; although the ball head detection method has many advantages, some key technical problems still need to be solved in practical applications. Therefore, how to develop a more accurate, reliable and adaptable taper internal thread pitch diameter detection device has become an important topic in the current field of thread detection technology. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a taper internal thread pitch diameter detection device to solve the existing problems and realize the detection of the pitch diameter of taper threads.

[0008] To achieve the above object, the present invention provides the following technical solution: a taper internal thread pitch diameter detection device, including a measuring bracket, two ball head brackets slidably installed on the measuring bracket, a micrometer, an end face dial indicator, a probe assembly and a synchronizing block; the ball head bracket includes a ball head bracket body and a ball head, one end of the ball head bracket body is provided with a ball head fixing groove, and the other end is provided with a guide rail groove. Two ball heads are respectively installed in the ball head fixing grooves and contact with the thread profile surface to form a thread pitch diameter generatrix; the probe assembly includes a measuring rod, and both ends of the measuring rod are provided with ball head measuring heads. One end of the ball head measuring head contacts the measuring point of the thread profile, and the other end is connected to the bottom of the end face dial indicator through the synchronizing block, for transmitting the displacement of the measuring point to the end face dial indicator; the micrometer is fixed on the measuring bracket for measuring the distance between the thread end face and the axis of the ball head bracket; the synchronizing block is rotatably installed in the measuring bracket for converting the displacement of the probe assembly into the reading of the end face dial indicator; through the reading of the end face dial indicator and the measured value of the micrometer, combined with the known taper angle, the pitch diameter of the taper internal thread is calculated.

[0009] Optionally, the measuring bracket is provided with a guide rail, and the ball head bracket is slidably engaged with the guide rail through the guide rail groove.

[0010] Optionally, the synchronizing block is installed in the measuring bracket through a synchronizing block fixing hole and can rotate around the synchronizing block fixing hole.

[0011] Optionally, a synchronizing block installation relief hole is also opened at the position of the synchronizing block installation relief hole in the measuring bracket.

[0012] Optionally, the micrometer is fixed on the measuring bracket through a micrometer installation hole.

[0013] Optionally, the end face dial indicator is installed on the measuring bracket through an end face micrometer fixing hole.

[0014] Optionally, the probe assembly further includes a mounting sleeve, a spring and a fixing cover for fixing the measuring rod and ensuring its measurement accuracy.

[0015] Optionally, the pitch diameter of the tapered internal thread is calculated by the following formula:

[0016]

[0017] where D is the pitch diameter of the thread end face; L is the distance between the measuring point on the generatrix of the pitch diameter and the measuring point perpendicular to the generatrix; φ is the distance between the intersection points of the generatrices of the pitch diameter; and α is the taper angle of the internal thread.

[0018] The beneficial effects of the present invention are as follows: By using the movable ball head to contact the thread profile surface and combining the precise measurements of the micrometer and the dial indicator, the accurate detection of the pitch diameter of the tapered thread is achieved. The structure is simple, the operation is convenient, and the measurement accuracy is high, effectively solving the problems existing in the traditional detection technology of the pitch diameter of internal threads, improving the accuracy and reliability of detection, and being applicable to various occasions of detecting the pitch diameter of internal threads.

[0019] Other advantages, objectives, and features of the present invention will be elaborated to some extent in the subsequent description, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0021] Figure 1 is a three-dimensional view of the overall structure of the present invention;

[0022] Figure 2 is Figure 1 a partial cross-sectional view of the internal structure of;

[0023] Figure 3 is a three-dimensional view of the measuring bracket of the present invention;

[0024] Figure 4 is Figure 3 a partial cross-sectional view of the internal structure of;

[0025] Figure 5 is a schematic structural view of the ball head bracket of the present invention;

[0026] Figure 6 is a schematic structural view of the measuring assembly of the present invention;

[0027] Figure 7 is a schematic diagram of the measurement principle of the present invention.

[0028] Reference numerals: measuring bracket 1, relief hole 11 for mounting synchronizing block, micrometer mounting hole 12, guide rail 13, end micrometer fixing hole 14, synchronizing block fixing hole 15, ball head bracket 2, ball head bracket body 21, guide rail groove 211, ball head 22, micrometer 3, dial indicator 4, probe assembly 5, measuring rod 51, first ball head measuring head 511, second ball head measuring head 512, mounting sleeve 52, spring 53, fixing cover 54, synchronizing block 6. Specific embodiments

[0029] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0030] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as limiting the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0031] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] Please refer to Figures 1 to 7 , which is a taper internal thread pitch diameter detection device. The present invention uses a ball head to contact the tooth profile surface, measures the distance from the parallel line to the thread pitch diameter generatrix and the distance from the end face of the measurement point, and measures the taper thread pitch diameter when the taper angle is known. The taper internal thread pitch diameter detection device of the present invention mainly includes the following components: measuring bracket 1, two ball head brackets 2, micrometer 3, dial indicator 4, probe assembly 5, and synchronizing block 6.

[0033] The measuring bracket 1 serves as the carrier of the entire detection device, and all other components are installed thereon. A guide rail 13 is provided on the measuring bracket 1 for the sliding installation of the ball head bracket 2. The measuring bracket 1 is also provided with a synchronous block installation relief hole 11, a micrometer installation hole 12, an end micrometer fixing hole 14, and a synchronous block fixing hole 15 for the installation and fixation of the synchronous block 6, the micrometer 3, and the end dial indicator 4 respectively.

[0034] The ball head bracket 2 includes a ball head bracket body 21 and a ball head 22. One end of the ball head bracket body 21 is provided with a ball head fixing groove, and the other end is provided with a guide rail groove 211, which cooperates with the guide rail 13 on the measuring bracket 1 to achieve sliding. Two ball heads 22 are respectively installed in the ball head fixing grooves and contact the thread flank surface to form a thread pitch diameter generatrix.

[0035] The micrometer 3 is fixed to the measuring bracket 1 through the micrometer installation hole 12. The micrometer 3 is used to measure the distance between the thread end face and the set reference plane (such as a certain fixed surface of the measuring bracket 1) and record this value as the basis for subsequent calculations.

[0036] The end dial indicator 4 is installed on the measuring bracket 1 through the end micrometer fixing hole 14. The end dial indicator 4 is used to display the displacement of the probe assembly 5, that is, the displacement of the measurement point on the thread pitch diameter line, so as to indirectly reflect the change of the thread pitch diameter.

[0037] The probe assembly 5 includes a measuring rod 51, a mounting sleeve 52, a spring 53, and a fixing cover 54. Both ends of the measuring rod 51 are provided with ball head measuring heads, namely a first ball head measuring head 511 and a second ball head measuring head 512. The second ball head measuring head 512 contacts the measurement point of the thread flank to sense the change of the thread pitch diameter. The first ball head measuring head 511 is connected to the bottom of the end dial indicator 4 through the synchronous block 6 to transmit the displacement of the measurement point to the end dial indicator 4. The spring 53 and the fixing cover 54 are used to fix the measuring rod 51 and ensure its measurement accuracy and stability.

[0038] The synchronous block 6 is installed in the measuring bracket 1 through the synchronous block fixing hole 15 and can rotate around the synchronous block fixing hole 15. The synchronous block 6 is used to convert the displacement of the probe assembly 5 into the reading of the end dial indicator 4 to achieve the indirect measurement of the thread pitch diameter.

[0039] The working principle of the present invention is as follows:

[0040] S1. Place the measuring bracket 1 above the thread to be measured, and adjust the position of the ball head bracket 2 so that the two ball heads 22 respectively contact the flank surfaces on both sides of the thread to form a thread pitch diameter generatrix.

[0041] S2. Use the micrometer 3 to measure the distance between the thread end face and the set reference plane and record this value as part of L (or for subsequent calculations).

[0042] In step S3, move the mobile probe assembly 5 to make the second ball head probe 512 contact the measurement point of the thread profile. At this time, the first ball head probe 511 will transmit the displacement amount to the dial indicator 4 through the synchronization block 6.

[0043] In step S4, read the reading of the dial indicator 4. This reading reflects the distance change between the measurement point and the fixed ball head (i.e., the ball head 22 or a certain part of the measurement bracket 1 that forms a fixed distance with the end face), that is, the change in the pitch diameter of the thread.

[0044] In step S5, combining the known taper angle α, the measurement value of the micrometer 3, and the reading of the dial indicator 4, the pitch diameter D of the tapered internal thread is obtained through the following calculation formula:

[0045]

[0046] Where D is the pitch diameter of the thread end face; L is the distance between the measurement point on the pitch diameter along the generatrix and the measurement point perpendicular to the generatrix; φ is the distance between the intersection point of the pitch diameter generatrix and the corresponding pitch diameter generatrix; α is the internal thread taper angle.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A device for detecting the middle diameter of a tapered internal thread, characterized in that: A measuring bracket, two ball head brackets slidably mounted on the measuring bracket, a micrometer, an end dial indicator, a probe assembly and a synchronization block; The ball head frame comprises a ball head frame body and a ball head, one end of the ball head frame body is provided with a ball head fixing groove, and the other end is provided with a guide groove, and two ball heads are respectively installed in the ball head fixing grooves and contact the thread profile surface to form a thread mid-diameter generatrix; The probe assembly includes a measuring rod, and ball head measuring heads are provided at both ends of the measuring rod, one end of the ball head measuring head contacts the measuring point of the thread profile, and the other end is connected to the bottom of the end face dial indicator through the synchronization block, so as to transmit the displacement of the measuring point to the end face dial indicator; The micrometer is fixed on the measuring bracket and is used to measure the distance between the thread end face and the axis of the ball head bracket; The synchronization block is rotatably mounted in the measuring bracket and is used to convert the displacement of the probe assembly into the reading of the end dial indicator; The median diameter of the tapered internal thread is calculated by using the reading of the end face dial indicator and the measured value of the micrometer in combination with the known taper angle.

2. The device for detecting the middle diameter of a tapered internal thread according to claim 1, characterized in that: The measuring bracket is provided with a guide rail, and the ball head bracket cooperates with the guide rail through a guide rail groove to achieve sliding.

3. The device for detecting the middle diameter of a tapered internal thread according to claim 1, characterized in that: The synchronization block is installed in the measuring bracket through the synchronization block fixing hole and can rotate around the synchronization block fixing hole.

4. The device for detecting the middle diameter of a tapered internal thread according to claim 3, characterized in that: A synchronization block installation clearance hole is also provided in the measuring bracket at the position of the synchronization block installation clearance hole.

5. The device for detecting the middle diameter of a tapered internal thread according to claim 1, characterized in that: The micrometer is fixed on the measuring bracket through the micrometer mounting hole.

6. The device for detecting the middle diameter of a tapered internal thread according to claim 1, characterized in that: The end face dial indicator is installed on the measuring bracket through the end face micrometer fixing hole.

7. The device for detecting the middle diameter of a tapered internal thread according to claim 1, characterized in that: The probe assembly also includes a mounting sleeve, a spring and a fixing cover, which are used to fix the measuring rod and ensure its measuring accuracy.

8. The device for detecting the middle diameter of a tapered internal thread according to claim 1, characterized in that: The pitch diameter of the tapered internal thread is calculated by the following formula: Wherein, D is the mean diameter of the thread end face; L is the distance between the measuring point along the mean diameter generatrix and the measuring point perpendicular to the generatrix; φ is the distance between the intersection of the mean diameter generatrix and the corresponding mean diameter generatrix; α is the taper angle of the internal thread.

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