A method for reworking the position deviation of positioning pin holes

Abstract

The present invention relates to a method for reworking the position deviation of a positioning pin hole. First, the pin hole with a position deviation is determined based on an assessment. A replacement pin with a larger diameter than the original pin is fixedly connected to the pin hole by a thread. The replacement pin is processed, and its diameter size is based on the original pin diameter size and its axial position is based on the theoretical position of the pin on the part body. A flange is formed by the flange to form a threaded clamping and limiting structure to prevent the replacement pin from being screwed into the threaded hole when processing the diameter size. A complementary structure of the flange is formed by cutting the end of the pin hole to form a positioning end face used for assembly that is the same as the original pin hole. After the processing is completed, its position and diameter size are re-evaluated to see if they meet the assembly requirements. If they still do not meet the requirements, a new replacement pin can be replaced and processed until the assembly requirements are met. The beneficial effect of the present invention is that it can conveniently carry out rework of pin holes with inaccurate positions, the processing difficulty is low, it has the characteristic of being repeatedly adjustable, and it effectively reduces costs.

Description

Technical Field

[0001] The invention relates to the technical field of pin hole reworking methods, and in particular to a method for reworking position deviation of a positioning pin hole. Background Art

[0002] Pin holes are fixed holes for placing pins. Pin holes and pins are often used to fix the relative positions between parts during assembly. They are important auxiliary parts during combined processing and assembly. Pins and pin holes are generally interference fit. Pin holes have high requirements for positioning reference and processing accuracy during production and processing, and the tolerance requirements are relatively strict.

[0003] The existing technology has the following shortcomings: when the pin hole of a component is out of tolerance and the pin assembly cannot be completed, the component will be scrapped and replaced with a new component to reprocess the pin hole to meet the requirements, which increases the cost of manufacturing materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for reworking the position deviation of a positioning pin hole to address the problem that the processing method after the pin hole exceeds the tolerance sacrifices performance and increases costs, so as to recycle the parts with the pin hole exceeding the tolerance so that they can be assembled.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for reworking a positioning pin hole position deviation comprises the following steps:

[0007] S1. Processing the original pin hole: Cut the pin hole on the part body that is out of tolerance from the end to about one-eighth of its length, and process the internal thread of the pin hole to make it a threaded hole;

[0008] S2. Processing a replacement pin: The replacement pin is the same length as the original pin, the original pin being the pin that fits into the pin hole, the diameter of the replacement pin being larger than the major diameter of the internal thread of the threaded hole, one end of the replacement pin being cut to form an external thread corresponding to the internal thread of the threaded hole, the length of the external thread being equal to the difference between the length of the original pin extending into the pin hole and the thickness of the cut pin hole, the portion with the external thread constituting the root of the replacement pin;

[0009] S3. Assemble the part body and the replacement pin: completely screw the root into the threaded hole;

[0010] S4. Re-process the replacement pin: fix the part body, and process the side of the replacement pin without threads according to the theoretical axial position and theoretical diameter size to form the head of the replacement pin. The head is assembled with the pin hole of another component in the form of a pin. A part of the side close to the external thread is left unprocessed to form the flange of the replacement pin. The thickness of the flange is the thickness of the cut pin hole.

[0011] The present invention adopts the above-mentioned technical solution, which can conveniently rework pin holes with inaccurate position, has low processing difficulty, and has the characteristic of being repeatedly adjustable. Specifically, first, according to the assessment, the pin hole with out-of-tolerance position is determined, and a replacement pin with a larger diameter than the original pin is fixedly connected to the pin hole by threading. The replacement pin is processed, and its diameter size is based on the diameter size of the original pin, and its axial position is based on the theoretical position size of the pin on the part body. A flange is formed by processing, and a threaded clamping and limiting structure is formed by the flange to prevent the replacement pin from being screwed into the threaded hole during the processing of the diameter size, resulting in a protruding length that does not conform to the theory. A complementary structure of the flange is formed by cutting the end of the pin hole to form a positioning end face used for assembly that is the same as the original pin hole. After the processing is completed, its position and diameter size are re-evaluated to see if they meet the assembly requirements. If they still do not meet the requirements, a new replacement pin can be replaced and processed until the assembly requirements are met. For defects in the same batch caused by wear of the processing equipment, the direction of the pin hole offset is basically the same. Therefore, the same cutting process can be used to batch process the replacement pins in the batch, which can improve the recovery speed to a certain extent.

[0012] Preferably, the internal thread of the threaded hole is tapped using a spiral groove tap, and the replacement pin is provided with an external thread at one end thereof and is machined to have the same taper as the spiral groove tap. The internal thread is primarily used to install the replacement pin, while also allowing the replacement pin to be removed, facilitating secondary replacement of the replacement pin. When the replacement pin is screwed into the internal thread, the flange abuts against the end of the threaded hole to limit its position. The thread and flange prevent relative movement between the replacement pin and the component body during machining of the head, which could affect positioning during assembly. Because the key to determining whether a pin is qualified is the machining accuracy of the head, the internal thread is tapped, which has lower machining accuracy but is faster and less expensive. Spiral groove tapping allows iron chips to be discharged along the spiral groove, improving the surface quality of the thread. Because the tap head has a certain taper, the tap head portion is not fully formed when the tap abuts the bottom of the threaded hole. Machining the replacement pin with the same taper as the spiral groove tap allows the replacement pin to be inserted deeper into the component body, avoiding cutting of a portion of the root.

[0013] Preferably, the external thread of the replacement pin is processed by turning.

[0014] Preferably, the head of the replacement pin is machined on a lathe, with the part body secured to a fixture on the lathe. The lathe tool rotates around the replacement pin and feeds forward to complete machining of the replacement pin head, with its rotational direction being consistent with the direction in which the replacement pin is tightened. This prevents the replacement pin from unscrewing due to friction during the turning process. During unscrewing, the tool will also bear the force generated by the unscrewing pin, which is parallel to the tool feed direction, increasing the stress on the lathe and reducing its service life.

[0015] The beneficial effect of the present invention is that parts with out-of-tolerance pin holes can be recycled, avoiding the scrapping of parts with excessive out-of-tolerance pin holes, saving a lot of costs, and the recycling cost is low and the difficulty is small. The method can be repeated multiple times for the same pin hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the assembly of the pin hole and the original pin;

[0017] Figure 2 Schematic diagram of the structure of the threaded hole after cutting;

[0018] Figure 3 It is a schematic diagram of the assembly of the threaded hole and the replacement pin;

[0019] Figure 4 Schematic diagram of the final state;

[0020] Figure 5 Schematic diagram of the structure of the replacement pin.

[0021] Markings in the figure: 1-part body, 2-pin hole, 21-internal thread, 22-threaded hole, 3-original pin, 31-replacement pin, 32-external thread, 33-root, 34-head, 35-flange. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] like Figures 1 to 5 As shown, this embodiment provides a method for reworking the position deviation of a positioning pin hole, comprising the following steps:

[0025] S1. Processing the original pin hole: Cut the out-of-tolerance pin hole 2 on the part body 1 by one-eighth of its length from the end, and process the internal thread 21 of the pin hole 2 to make it a threaded hole 22;

[0026] S2. Processing the replacement pin: The replacement pin 31 is the same length as the original pin 3 and has a diameter larger than the major diameter of the internal thread 21 of the threaded hole 22. One end of the replacement pin 31 is cut to form an external thread 32 corresponding to the internal thread 21 of the threaded hole 22. The length of the external thread 32 is equal to the difference between the length of the original pin 3 extending into the pin hole 2 and the thickness of the cut pin hole 2. The portion with the external thread 22 constitutes the root 33 of the replacement pin 31.

[0027] S3. Assemble the part body and the replacement pin: completely screw the root portion 33 into the threaded hole 22;

[0028] S4. Re-process the replacement pin: fix the part body 1, and process the side of the replacement pin 31 without threads according to the theoretical axial position and theoretical diameter size to form the head 34 of the replacement pin 31. The head 34 is assembled with the pin hole of another component in the form of a pin. A part of the side close to the external thread 32 is left unprocessed to form the flange 35 of the replacement pin 31. The thickness of the flange 35 is the thickness of the cut pin hole 2.

[0029] The internal thread 21 of the threaded hole 22 is tapped by a spiral groove tap, and one end of the replacement pin 31 is provided with an external thread 32 which is processed to form the same taper as the spiral groove tap.

[0030] The external thread 32 of the replacement pin 31 is processed by turning.

[0031] The head 34 of the replacement pin 31 is processed by a lathe, and the part body 1 is fixed on a fixture of the lathe. The tool of the lathe rotates around the replacement pin 31 and feeds to complete the processing of the head.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for reworking the position deviation of a positioning pin hole, characterized in that: The following steps are involved: S1. Processing the original pin hole: cutting the pin hole (2) on the part body (1) from the end to one eighth of its length, and processing the internal thread (21) of the pin hole (2) to make it a threaded hole (22); S2. Processing a replacement pin: the replacement pin (31) is equal in length to the original pin (3), and its diameter is larger than the major diameter of the internal thread (21) of the threaded hole (22). One end of the replacement pin (31) is cut to form an external thread (32) corresponding to the internal thread (21) of the threaded hole (22). The length of the external thread (32) is equal to the difference between the length of the original pin (3) extending into the pin hole (2) and the thickness of the pin hole (2) cut. The portion provided with the external thread (22) constitutes the root (33) of the replacement pin (31); S3, assembling the part body and the replacement pin: completely screwing the root portion (33) into the threaded hole (22); S4. Re-processing the replacement pin: fix the part body (1), and process the side of the replacement pin (31) without threads according to the theoretical axis position and theoretical diameter size to form the head (34) of the replacement pin (31). The head (34) is assembled with the pin hole of another component in the form of a pin, and a part of the side close to the external thread (32) is left unprocessed to form the flange (35) of the replacement pin (31). The thickness of the flange (35) is the thickness of the cut pin hole (2).

2. The method for reworking the position deviation of the positioning pin hole according to claim 1, characterized in that: The internal thread (21) of the threaded hole (22) is tapped with a spiral groove tap, and the replacement pin (31) is provided with an external thread (32) whose one end is processed to have the same taper as the spiral groove tap.

3. The method for reworking the position deviation of the positioning pin hole according to claim 1, characterized in that: The external thread (32) of the replacement pin (31) is processed by turning.

4. The method for reworking the position deviation of the positioning pin hole according to claim 1, characterized in that: The head (34) of the replacement pin (31) is processed by a lathe, the part body (1) is fixed on a fixture of the lathe, and the tool of the lathe rotates around the replacement pin (31) and feeds to complete the processing of the head (34).

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