Extrusion-rolling combined forming device and method for internally threaded thin-wall fastener

Abstract

The application discloses an extrusion-rolling composite forming device and method for an internal thread thin-wall fastener, which comprises a thin-wall fastener, a roller, a fixed clamp and an extrusion tap arranged on a machine spindle, the extrusion tap is arranged on the inner side of the thin-wall fastener and is used for forming the internal thread of the thin-wall fastener, the fixed clamp comprises a base and a clamp, the thin-wall fastener to be formed is arranged on the base, and the clamp is arranged on the outer side of the bottom end of the unformed area of the thin-wall fastener, the roller is arranged on the outer side of the to-be-formed area of the thin-wall fastener, the roller can adopt a cylindrical roller or a ball roller, and the outer surface of the thin-wall fastener is rolled by the roller when the internal thread of the thin-wall fastener is formed by tapping with the extrusion tap. The composite extrusion effect of the extrusion tap on the inner side of the thin-wall fastener and the roller on the outer side is utilized, the forming performance of the internal thread and the forming quality of the outer surface are improved, and the cracking and uneven defects of the outer surface in the extrusion tapping process of the internal thread thin-wall fastener are effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of forming of internally threaded thin-wall fasteners, and in particular to an extrusion-rolling combined forming device and method for internally threaded thin-wall fasteners. BACKGROUND

[0002] Common forming methods for the internal thread of a fastener include milling and tapping, etc. For thin-wall fasteners with a wall thickness of less than or equal to 1 mm, the milling process is prone to instability and breakage defects, so non-removing material internal thread forming methods such as extrusion tapping are often used. However, due to the thin wall thickness, the formed thread is prone to incomplete filling defects, and the forming precision and performance are poor. In addition, after the internal thread is formed, the outer surface is prone to concave-convex defects caused by the internal thread, and the surface quality is poor. In actual application, when the fastener bears axial tensile load, it is prone to breakage.

[0003] In view of the above problems, the present application innovatively provides an extrusion-rolling combined forming device and method for the internal thread of a thin-wall fastener. SUMMARY

[0004] The purpose of the present application is to solve the technical problems existing in the prior art and provide an extrusion-rolling combined forming device and method for an internally threaded thin-wall fastener.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows: an extrusion-rolling combined forming device for an internally threaded thin-wall fastener, comprising a thin-wall fastener, a roller, a fixed clamp, and an extrusion tap provided on a machine spindle, the extrusion tap is located on the inside of the thin-wall fastener for the internal thread forming of the thin-wall fastener, the fixed clamp comprises a base and a clamp, the thin-wall fastener to be formed is arranged on the base, and the clamp is arranged at the outer side of the bottom end of the unformed area of the thin-wall fastener, the roller is arranged on the outside of the to-be-formed area of the thin-wall fastener, and the roller can adopt a cylindrical roller or a ball roller.

[0006] Preferably, when the length of the thin-wall fastener is less than or equal to the length of the cylindrical roller, the roller adopts a cylindrical roller, and the cylindrical roller is located on the radial outside of the thin-wall fastener; when the length of the thin-wall fastener is greater than the length of the cylindrical roller, the roller adopts a ball roller, the ball roller is located on the outside of the thin-wall fastener, and the center axis of the ball roller coincides with the center axis of the thin-wall fastener.

[0007] The application further discloses an extrusion-rolling composite forming method of the internal thread thin-wall fastener, and the method comprises the extrusion-rolling composite forming device of the internal thread thin-wall fastener.

[0008] Preferably, the extrusion forming of the outer side of the thin-wall fastener by the roller comprises the following two cases.

[0009] A. When the length of the thin-wall fastener is less than or equal to the length of the cylindrical roller, the roller is a cylindrical roller, at the initial forming moment, the cylindrical roller is located at the radial outer side of the thin-wall fastener to be formed, and at the forming moment, the cylindrical roller is radially rolled around the thin-wall fastener to perform the extrusion-rolling composite forming on the thin-wall fastener.

[0010] B. When the length of the thin-wall fastener is greater than the length of the cylindrical roller, the roller is a ball roller, at the initial forming moment, the ball roller is located at the outer side of the thin-wall fastener to be formed, and the central axis of the ball roller is coincident with the central axis of the thin-wall fastener, at the forming moment, the ball roller is radially rolled around the thin-wall fastener and synchronously axially moved with the extrusion tap to perform the extrusion-rolling composite forming on the thin-wall fastener.

[0011] The application has the following beneficial effects:

[0012] The application utilizes the composite extrusion of the inner extrusion tap and the outer roller of the thin-wall fastener to improve the forming performance of the internal thread and the forming quality of the outer surface, and effectively avoids the cracking and uneven defects of the outer surface during the extrusion tapping of the internal thread thin-wall fastener. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and serve to explain the principles of the application.

[0014] Fig. 1 FIG. 1 is a schematic diagram of the extrusion-rolling composite forming principle of the internal thread thin-wall fastener in the application;

[0015] Fig. 2This is a diagram showing the positional relationship between the mold and the workpiece at the initial moment of the cylindrical roller forming process of this invention.

[0016] Fig. 3 This is a schematic diagram of the cylindrical roller in this invention;

[0017] Fig. 4 This is a schematic diagram of the extrusion-rolling composite forming principle of the internal thread thin-walled fastener using ball rollers in this invention.

[0018] Fig. 5 This is a diagram showing the positional relationship between the mold and the workpiece at the initial moment of ball roller forming in this invention;

[0019] Fig. 6 This is a schematic diagram of the ball roller in this invention.

[0020] Attached image captions:

[0021] 1. Extrusion tap 2. Thin-walled fastener 3-1. Cylindrical roller 3-2. Cylindrical roller 4-1. Fixture 4-2. Base. Detailed Implementation

[0022] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0024] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0025] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0026] Example 1

[0027] Reference Figs. 1-3 This embodiment is for a thin-walled fastener 2 with a length less than or equal to the length of the cylindrical roller 3-2. The roller is a cylindrical roller 3-1. The forming principle diagram includes an extrusion tap 1, a thin-walled fastener 2, a cylindrical roller 3-1, and a fixing fixture. The fixing fixture includes a base and a fixture. The thin-walled fastener 2 is set on the base 4-2 and fixed by the fixture 4-1. The fixture 4-1 is set at the bottom outer side of the unformed area of ​​the thin-walled fastener 2. The roller is set on the outer side of the area to be formed of the thin-walled fastener 2.

[0028] At the initial moment of forming, the thin-walled fastener 2 to be formed is fixed by the fixing fixture; the extrusion tap 1 is located in the direction of the central axis of the thin-walled fastener 2 to be formed, and the extrusion tap 1 coincides with the central axis of the thin-walled fastener 2 to be formed; the cylindrical roller 3-1 is located on the radial outer side of the thin-walled fastener 2 to be formed.

[0029] During forming, the thin-walled fastener 2 is fixed in place by the fixing fixture; the extrusion tap 1 is driven to rotate by the machine spindle and simultaneously performs tapping motion along the axial direction of the thin-walled fastener 2; the cylindrical roller 3-1 performs radial rolling around the thin-walled fastener 2, performing extrusion-rolling composite forming on the thin-walled fastener 2.

[0030] Example 2

[0031] Reference Figs. 4-6 This embodiment is for a thin-walled fastener 2 with a length greater than that of the cylindrical roller 3-1. The roller is a ball roller 3-2. The forming principle diagram includes an extrusion tap 1, a thin-walled fastener 2, a ball roller 3-2, and a fixing fixture. The fixing fixture includes a base and a fixture. The thin-walled fastener 2 is set on the base 4-2 and fixed by the fixture 4-1. The fixture 4-1 is set at the bottom outer side of the unformed area of ​​the thin-walled fastener 2. The roller is set on the outer side of the area to be formed of the thin-walled fastener 2.

[0032] At the initial moment of forming, the thin-walled fastener 2 to be formed is fixed by a fixing fixture; the extrusion tap 1 is located in the direction of the central axis of the thin-walled fastener 2 to be formed, and the extrusion tap 1 coincides with the central axis of the thin-walled fastener 2 to be formed; the ball roller 3-2 is located on the outside of the thin-walled fastener 2 to be formed, and the central axis of the ball roller 3-2 coincides with the central axis of the thin-walled fastener 2.

[0033] During the forming process, the thin-walled fastener 2 to be formed is fixed in place by the fixing fixture; the extrusion tap 1 is driven to rotate by the machine spindle and simultaneously performs tapping motion along the axial direction of the thin-walled fastener 2; the ball rollers 3-2 perform radial rolling around the thin-walled fastener 2 and move axially synchronously with the extrusion tap 1 to perform extrusion-rolling composite forming of the thin-walled fastener.

[0034] This invention utilizes the combined extrusion action of the extrusion tap 1 on the inner side and the roller on the outer side of the thin-walled fastener 2 to improve the forming performance of the internal thread and the forming quality of the outer surface, effectively avoiding cracking and unevenness defects on the outer surface during the extrusion tapping process of the thin-walled fastener 2 with internal thread.

[0035] Without causing conflict, those skilled in the art can freely combine and use the above-mentioned additional technical features.

[0036] The above description is only a preferred embodiment of the present invention. Any technical solution that achieves the purpose of the present invention by essentially the same means is within the protection scope of the present invention.

Claims

1. A method for extrusion-rolling composite forming of thin-walled internally threaded fasteners, characterized in that: An extrusion-rolling composite forming device for a thin-walled fastener with internal threads is provided. The device includes a thin-walled fastener (2), rollers, a fixing fixture, and an extrusion tap (1) mounted on a machine spindle. The extrusion tap (1) is located inside the thin-walled fastener (2) for forming the internal threads of the thin-walled fastener (2). The fixing fixture includes a base (4-2) and a clamp (4-1). The thin-walled fastener (2) to be formed is mounted on the base (4-2), and the clamp (4-1) is mounted at the bottom outer side of the unformed area of ​​the thin-walled fastener (2). The rollers are mounted outside the unformed area of ​​the thin-walled fastener (2). The rollers can be cylindrical rollers (3-1) or ball rollers (3-2). The forming method includes: at the initial moment of forming, the thin-walled fastener (2) to be formed is fixed by a fixing fixture to ensure that the thin-walled fastener (2) remains stationary throughout the forming process; during forming, the inner side of the thin-walled fastener (2) rotates through the extrusion tap (1) and performs a tapping motion along the axial direction of the thin-walled fastener (2) to form an inner thread; the outer side of the thin-walled fastener (2) is radially rolled around the thin-walled fastener (2) by the roller to form an outer thread, thereby realizing the extrusion-rolling composite forming of the thin-walled fastener (2); When the thin-walled fastener (2) is extruded using rollers on the outside, the following two situations apply; A. When the length of the thin-walled fastener (2) is less than or equal to the length of the cylindrical roller (3-1), the roller is a cylindrical roller (3-1). At the initial moment of forming, the cylindrical roller (3-1) is located on the radial outer side of the thin-walled fastener (2) to be formed. During forming, the cylindrical roller (3-1) performs radial rolling around the thin-walled fastener (2) to perform extrusion-rolling composite forming on the thin-walled fastener (2). B. When the length of the thin-walled fastener (2) is greater than the length of the cylindrical roller (3-1), the roller is a ball roller (3-2). At the initial moment of forming, the ball roller (3-2) is located outside the thin-walled fastener (2) to be formed, and the central axis of the ball roller (3-2) coincides with the central axis of the thin-walled fastener (2). During forming, the ball roller (3-2) performs radial rolling around the thin-walled fastener (2) and moves axially synchronously with the extrusion tap (1) to perform extrusion-rolling composite forming on the thin-walled fastener (2).

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