Measuring tool and measuring method for detecting external thread of cylinder

Abstract

The invention provides a measuring tool for detecting a cylindrical external thread, which is used for measuring the pitch diameter of the thread of a cylindrical external thread part and comprises a cylindrical body, and the center of the body is provided with an internal conical thread structure which is used for being connected with the cylindrical external thread part to be measured; the small-diameter end of the inner conical thread structure is located on the top face of the body, the large-diameter end of the inner conical thread structure is located on the bottom face of the body, a sunken step face is arranged on the top face of the body, the step face is tangent to the inner conical thread structure of the body to form a notch, vertical faces are formed on the two sides of the notch, and one or more scale marks parallel to the top face are arranged on the edge of the notch of the vertical face on at least one side. According to the measuring tool for detecting the cylindrical external thread and the measuring method thereof, the pitch diameter value of the thread of the cylindrical external thread part can be detected through one-time screwing, compared with a conventional detection method, the measuring tool is more efficient, and a more accurate detection result can be obtained; therefore, the cylindrical external thread part can be classified and sorted according to the detected pitch diameter value of the thread.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, in particular to a measuring tool and a measuring method capable of detecting the thread pitch diameter of a cylindrical external thread part. Background Art

[0002] The measuring tool for detecting cylindrical external threads is usually a gauge. The inside of the gauge adopts cylindrical internal threads, and the diameter size of the cylindrical internal threads is designed. Then the threaded part is screwed into the internal threads of the gauge. If it can be screwed in, it is determined that the diameter of the threaded part is smaller than the diameter size determined by the gauge; if it cannot be screwed in, it is determined that the diameter of the threaded part is larger than the diameter size determined by the gauge.

[0003] Since a gauge can only determine whether a threaded part is larger or smaller than its set diameter, two gauges are usually required to be used in production practice to determine whether the thread size of a part meets the tolerance range requirements. One gauge corresponds to the upper limit of the tolerance (parts that meet the requirements can pass, so it is called a "go gauge"), and the other gauge corresponds to the lower limit of the tolerance (parts that meet the requirements cannot pass, so it is called a "stop gauge"). When measuring the threads of threaded parts, it is necessary to be able to pass the go gauge but not the stop gauge, so as to determine whether the part meets the thread tolerance processing requirements.

[0004] However, the disadvantages of this design method are: first, it is necessary to measure with two gauges to determine whether the threaded parts meet the tolerance requirements. In order to ensure that the parts can pass the go gauge and not the stop gauge to avoid detection errors, repeated measurements are usually required in production practice to determine, resulting in low measurement efficiency; second, even if it is determined after two measurements that the threaded parts meet the tolerance requirements, it is impossible to further guide the range of the thread center diameter, and it is also impossible to meet the requirements of refined processing, so it is impossible to further classify qualified threaded parts. For example, although some parts meet the requirements, their thread size is actually too small, while the thread size of another part of the threaded parts is too large. For these problems, no further screening can be given. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a measuring tool and a measuring method for detecting cylindrical external threads, which can complete the side detection of cylindrical external thread parts at one time, determine whether they meet the tolerance requirements, and further determine the range of their external thread dimensions, so as to facilitate further screening of qualified parts, thereby solving the problem that traditional thread detection tools cannot further screen the dimensions of external threads.

[0006] In order to solve the above technical problems, the present invention provides a measuring tool for detecting cylindrical external threads, which is used to measure the thread mean diameter of cylindrical external thread parts, including a cylindrical body, and an internal tapered thread structure is provided at the center of the body for connecting with the cylindrical external thread part to be measured; the small diameter end of the internal tapered thread structure is located on the top surface of the body, and the large diameter end is located on the bottom surface of the body, and the top surface of the body is provided with a sunken step surface, which is tangent to the internal tapered thread structure of the body to form a notch, and vertical surfaces are formed on both sides of the notch, and one or more scale lines parallel to the top surface are provided on the edge of the notch of the vertical surface on at least one side.

[0007] When scale lines are respectively provided on the vertical surfaces on both sides, the scale lines on both sides are arranged in a staggered manner to correspond to thread median diameter values ​​of the internal tapered thread structure at different scale line positions.

[0008] The step surface is formed by milling the surface of the body.

[0009] The cutting portion of the step facing the internal conical thread structure of the body is less than 180 degrees, preferably 90-120 degrees.

[0010] Each of the scale lines corresponds to a true scale value and at least one correction value; wherein:

[0011] The true scale value directly corresponds to the thread pitch diameter value of the internal tapered thread structure at the scale line position;

[0012] The correction value corresponds to the scale line and corresponds to the thread pitch diameter value after the thread chamfer is corrected, that is, the correction value for the backward displacement of the thread locking position of the cylindrical external thread part to be measured caused by the thread chamfer.

[0013] The thread pitch diameter between the top surface and the step surface corresponds to the internal tapered thread structure, covering the tolerance range of the cylindrical external thread part to be measured.

[0014] The correction value is the thickness value of the thread chamfer obtained by calculation or estimation, and the distance that the end face of the cylindrical external thread part to be measured moves forward relative to the cylindrical thread caused by the thickness value, and the thread median diameter value of the internal tapered thread structure that causes the end face of the cylindrical external thread part to be measured to move backward by this distance.

[0015] The true scale value is expressed directly, such as D8.20, which means the thread center diameter is 8.20mm; the correction value can be recorded by marking or by using a correction table: the marking method is, for example, 0.5 / D8.35 (meaning chamfer thickness 0.5mm, thread center diameter correction value 8.35mm), 0.4 / D8.32 (meaning chamfer thickness 0.5mm, thread center diameter correction value 8.32mm), 0.2 / D8.26 (meaning chamfer thickness 0.2mm, thread center diameter correction value 8.26mm). The correction table can be used to organize the above marking methods into a table for looking up the true thread center diameter value.

[0016] The body is cylindrical, and a knurling structure is provided on the circumferential surface.

[0017] The present invention also provides a method for measuring the thread pitch diameter of a cylindrical external thread, comprising:

[0018] Obtain a measuring tool for detecting cylindrical external threads and a cylindrical external thread part to be measured;

[0019] Obtain the chamfer thickness of the cylindrical external thread part to be tested;

[0020] Screw the cylindrical external thread part to be tested into the large diameter end of the internal tapered thread structure of the measuring tool for testing the cylindrical external thread and bring it to the locking position;

[0021] Observe the scale line between the front end face of the cylindrical external threaded part to be tested in the locking position and the side edge of the notch of the nearest internal tapered thread structure;

[0022] According to the chamfer thickness of the cylindrical external threaded part to be measured, read the correction value on the scale line;

[0023] According to the read correction value, the cylindrical external thread parts to be tested are classified and sorted.

[0024] The measuring tool and measuring method for detecting cylindrical external threads provided by the present invention can detect the thread middle diameter value of cylindrical external thread parts by screwing in once, which is more efficient than conventional detection methods and can obtain more accurate detection results, so that cylindrical external thread parts can be classified and sorted according to the detected thread middle diameter values. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of the top view of the measuring tool according to the embodiment of the present invention.

[0026] Figure 2 It is a schematic diagram of the side structure of the measuring tool described in an embodiment of the present invention.

[0027] Figure 3 It is a schematic diagram of the side structure of the measuring tool described in an embodiment of the present invention.

[0028] Figure 4 for Figure 1 Cross-sectional view of section AA.

[0029] Figure 5 Schematic diagram of the measurement method. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] like Figure 1-5 As shown, the present invention provides a measuring tool for detecting cylindrical external threads, which is used to measure the thread median diameter of cylindrical external thread parts, including a cylindrical body 10, and an internal tapered thread structure 11 is provided at the center of the body 10 for connecting with the cylindrical external thread part 20 to be measured; the small diameter end of the internal tapered thread structure 11 is located on the top surface 12 of the body, and the large diameter end is located on the bottom surface 13 of the body, and the top surface 12 of the body is provided with a sunken step surface 14, and the step surface 14 is tangent to the internal tapered thread structure 11 of the body to form a notch 15, and vertical surfaces 16 are formed on both sides of the notch 15, and one or more scale lines 17 parallel to the top surface are provided on the notch edge of the vertical surface 16 on at least one side.

[0034] like Figure 3 As shown, when scale lines 17 are respectively provided on the vertical surfaces 16 on both sides, the scale lines on both sides are arranged in a staggered manner to correspond to the thread median diameter values ​​of the internal tapered thread structure at different scale line positions.

[0035] The step surface 14 is formed by milling the surface of the body.

[0036] The cutting portion of the stepped surface 14 to the internal conical thread structure of the body is less than 180 degrees, preferably 90-120 degrees, so as to ensure the integrity of the internal conical thread structure as much as possible. Since the cutting portion is less than 180 degrees, the measurement result can be accurate and the influence of the cutting on the measurement result can be reduced.

[0037] Each of the scale lines corresponds to a true scale value and at least one correction value; wherein:

[0038] The true scale value directly corresponds to the thread pitch diameter value of the internal tapered thread structure at the scale line position;

[0039] The correction value corresponds to the scale line and corresponds to the thread pitch diameter value after the thread chamfer is corrected, that is, the correction value for the backward displacement of the thread locking position of the cylindrical external thread part to be measured caused by the thread chamfer.

[0040] The thread pitch diameter between the top surface and the step surface corresponds to the internal tapered thread structure, covering the tolerance range of the cylindrical external thread part to be measured.

[0041] The correction value is the thickness value of the thread chamfer obtained by calculation or estimation, and the distance that the end face of the cylindrical external thread part to be measured moves forward relative to the cylindrical thread caused by the thickness value, and the thread median diameter value of the internal tapered thread structure that causes the end face of the cylindrical external thread part to be measured to move backward by this distance.

[0042] The true scale value is expressed directly, such as D8.20, which means the thread center diameter is 8.20mm; the correction value can be recorded by marking or by using a correction table: the marking method is, for example, 0.5 / D8.35 (meaning chamfer thickness 0.5mm, thread center diameter correction value 8.35mm), 0.4 / D8.32 (meaning chamfer thickness 0.5mm, thread center diameter correction value 8.32mm), 0.2 / D8.26 (meaning chamfer thickness 0.2mm, thread center diameter correction value 8.26mm). The correction table can be used to organize the above marking methods into a table for looking up the true thread center diameter value.

[0043] The main body is cylindrical, and a knurling structure is provided on the circumferential surface, so that it is convenient for handheld measurement.

[0044] like Figure 5 As shown, the present invention also provides a method for measuring the thread pitch diameter of a cylindrical external thread, comprising:

[0045] Obtain a measuring tool for detecting cylindrical external threads and a cylindrical external thread part to be measured;

[0046] Obtain the chamfer thickness of the cylindrical external thread part to be tested;

[0047] Screw the cylindrical external thread part to be tested into the large diameter end of the internal tapered thread structure of the measuring tool for testing the cylindrical external thread and bring it to the locking position;

[0048] Observe the scale line between the front end face of the cylindrical external threaded part to be tested in the locking position and the side edge of the notch of the nearest internal tapered thread structure;

[0049] According to the chamfer thickness of the cylindrical external threaded part to be measured, read the correction value on the scale line;

[0050] According to the read correction value, the cylindrical external thread parts to be tested are classified and sorted.

[0051] The measuring tool and measuring method for detecting cylindrical external threads provided by the present invention can detect the thread middle diameter value of cylindrical external thread parts by screwing in once, which is more efficient than conventional detection methods and can obtain more accurate detection results, so that cylindrical external thread parts can be classified and sorted according to the detected thread middle diameter values.

[0052] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A measuring tool for detecting cylindrical external threads, used to measure the thread pitch diameter of cylindrical external thread parts, comprising a cylindrical body, characterized in that: An internal tapered thread structure is provided at the center of the body for connecting to a cylindrical external thread part to be measured; the small diameter end of the internal tapered thread structure is located on the top surface of the body, and the large diameter end is located on the bottom surface of the body. A sunken step surface is provided on the top surface of the body, and the step surface is tangent to the internal tapered thread structure of the body to form a notch, and vertical surfaces are formed on both sides of the notch, and one or more scale lines parallel to the top surface are provided on the edge of the notch of at least one side of the vertical surface.

2. The measuring tool according to claim 1, characterized in that: When scale lines are respectively provided on the vertical surfaces on both sides, the scale lines on both sides are arranged in a staggered manner to correspond to thread median diameter values ​​of the internal tapered thread structure at different scale line positions.

3. The measuring tool according to claim 1, characterized in that: The step surface is formed by milling the surface of the body.

4. The measuring tool according to claim 1, characterized in that: The cutting portion of the step facing the internal conical thread structure of the body is less than 180 degrees, preferably 90-120 degrees.

5. The measuring tool according to claim 1, characterized in that: Each of the scale lines corresponds to a true scale value and at least one correction value; wherein: The true scale value directly corresponds to the thread pitch diameter value of the internal tapered thread structure at the scale line position; The correction value corresponds to the scale line and corresponds to the thread pitch diameter value after the thread chamfer is corrected, that is, the correction value for the backward displacement of the thread locking position of the cylindrical external thread part to be measured caused by the thread chamfer.

6. The measuring tool according to claim 1, characterized in that: The thread pitch diameter between the top surface and the step surface corresponds to the internal tapered thread structure, covering the tolerance range of the cylindrical external thread part to be measured.

7. The measuring tool according to claim 5, characterized in that: The correction value is the thickness value of the thread chamfer obtained by calculation or estimation, and the distance that the end face of the cylindrical external thread part to be measured moves forward relative to the cylindrical thread caused by the thickness value, and the thread median diameter value of the internal tapered thread structure that causes the end face of the cylindrical external thread part to be measured to move backward by this distance.

8. The measuring tool according to claim 7, characterized in that: The true scale value is expressed directly, such as D8.20, which means the thread center diameter is 8.20mm; the correction value can be recorded by marking or by using a correction table: the marking method is, for example, 0.5 / D8.35 (meaning chamfer thickness 0.5mm, thread center diameter correction value 8.35mm), 0.4 / D8.32 (meaning chamfer thickness 0.5mm, thread center diameter correction value 8.32mm), 0.2 / D8.26 (meaning chamfer thickness 0.2mm, thread center diameter correction value 8.26mm). The correction table can be used to organize the above marking methods into a table for looking up the true thread center diameter value.

9. The measuring tool according to claim 1, characterized in that: The body is cylindrical, and a knurling structure is provided on the circumferential surface.

10. A method for measuring the thread pitch diameter of a cylindrical external thread, characterized in that: include: Obtain the measuring tool for detecting cylindrical external threads and the cylindrical external threaded parts to be measured as described in any one of claims 1 to 9; Obtain the chamfer thickness of the cylindrical external thread part to be measured; Screw the cylindrical external thread part to be tested into the large diameter end of the internal tapered thread structure of the measuring tool for testing the cylindrical external thread and bring it to the locking position; Observe the scale line between the front end face of the cylindrical external threaded part to be tested in the locking position and the side edge of the notch of the nearest internal tapered thread structure; According to the chamfer thickness of the cylindrical external thread part to be measured, read the correction value on the scale line; According to the read correction value, the cylindrical external thread parts to be tested are classified and sorted.

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