Manufacturing method of hinge connecting piece of vehicle door hinge

Abstract

The invention discloses a manufacturing method of a hinge connecting piece of a vehicle door hinge, which relates to the technical field of hinges, and comprises the following steps: (1) carrying out hot rolling on a blank to form a strip-shaped profile; (2) the long-strip-shaped sectional material is cut in the width direction of the long-strip-shaped sectional material, and a first middle sectional material is obtained; (3) the first middle profile is conveyed to a cooling bed to be cooled; (4) after the first middle profile is cooled, the first middle profile is straightened; (5) cutting off a connecting part in the first middle profile to obtain two second middle profiles; (6) the second middle profile is cut in the width direction of the second middle profile, and a plurality of semi-finished products are obtained; (7) carrying out edge milling treatment on the semi-finished product through an edge milling machine; and (8) the semi-finished product is subjected to rust removal treatment, and then the hinge connecting piece needing to be manufactured is obtained. In the hot rolling process, the blank is subjected to uniform and symmetrical plastic deformation, so that residual internal stress is eliminated, and the phenomenon of warping, bending or twisting of a product is avoided.

Description

Technical Field

[0001] This invention relates to the field of hinge technology, and in particular to a method for manufacturing a hinge connecting piece for a car door hinge. Background Technology

[0002] Automotive door hinges are key components for the smooth opening of car doors. Existing automotive door hinge products include two hinge connecting pieces: a body connecting piece and a door connecting piece. Both the body connecting piece and the door connecting piece have a mounting end and a hinge end. The mounting end of the body connecting piece is fixedly connected to the car body, and the mounting end of the door connecting piece is fixedly connected to the car door. The hinge end of the door connecting piece is hinged to the hinge end of the body connecting piece via a hinge shaft. In this invention, the direction from the mounting end to the hinge end of the hinge connecting piece is referred to as the length direction of the hinge connecting piece.

[0003] Currently, the manufacturing method for hinge connecting pieces in automotive door hinges involves hot rolling to plastically deform the billet, rolling it into a long strip of steel. The cross-sectional shape of this strip is identical to the longitudinal cross-section of a single hinge connecting piece, and the width of the strip is equal to the length of the individual piece. The length of the strip is several times that of a single piece. The strip is then transversely cut along its width to create multiple hinge connecting pieces that meet design dimensions. However, hinge connecting pieces manufactured using this existing method often exhibit warping, bending, or twisting, resulting in residual stress and poor product stability. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing a hinge connecting piece for a car door hinge, so as to solve the problems existing in the prior art, eliminate residual stress in the hinge connecting piece, and improve the stability of the hinge connecting piece.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a method for manufacturing a hinge connecting piece for a car door hinge, comprising the following steps: (1) The billet is hot-rolled into a long strip profile. The direction from the mounting end to the hinge end of the hinge connecting piece to be manufactured is the length direction of the hinge connecting piece. The longitudinal section of the hinge connecting piece to be manufactured is the first section. The cross section of the long strip profile includes a connecting section and two first sections symmetrically distributed on both sides of the connecting section. The first section is connected to the connecting section at one end close to the connecting section. The part of the long strip profile where the connecting section is located is the connecting part. (2) Cut the long strip profile along the width direction to obtain a first intermediate profile, wherein the length of the first intermediate profile is an integer multiple of the width of a single hinge connecting piece; (3) The first intermediate profile is transported to a cooling bed for cooling; (4) After the first intermediate profile has cooled, the first intermediate profile is straightened using a straightening machine; (5) Cut off the connecting portion in the first intermediate profile to obtain two second intermediate profiles; (6) Cut the second intermediate profile along the width direction to obtain a plurality of semi-finished products, the length of the semi-finished products being equal to the width of the hinge connecting piece to be obtained; (7) The semi-finished product is finished by using a milling machine; (8) Remove rust from the semi-finished product to obtain the hinge connecting piece to be manufactured.

[0006] Preferably, the connecting cross section is rectangular or trapezoidal, and the connecting cross section is symmetrical about the center line of the two first cross sections in the cross section of the elongated profile.

[0007] Preferably, the billet is heated to 1180°C before hot rolling.

[0008] Preferably, in step (4), after the first intermediate profile has cooled to 50°C-60°C, the first intermediate profile is straightened by a straightening machine.

[0009] Preferably, in step (5), the connecting portion is removed by a laser cutting device.

[0010] Preferably, in step (5), the scrap material of the first intermediate profile is also removed by the laser cutting device.

[0011] Preferably, in step (8), the semi-finished product is subjected to shot blasting to remove rust using a shot blasting machine.

[0012] Preferably, after the first intermediate profile is straightened by the straightening machine, the curvature of the first intermediate profile is ≤ three per thousand.

[0013] Preferably, the shot blasting treatment time in step (8) is 10 to 18 minutes.

[0014] Preferably, the billet is round steel, and the hot rolling process has 9 hot rolling steps; the finishing process in step (7) includes milling, grinding and drilling.

[0015] The present invention achieves the following technical effects compared to the prior art: In the manufacturing method of the hinge connecting piece of the car door hinge of the present invention, the cross section of the long strip profile obtained by hot rolling has two symmetrically distributed first sections, and the connecting section in the cross section is also symmetrical. This makes the billet undergo uniform and symmetrical plastic deformation during hot rolling, and the metal flow is more uniform. It eliminates the residual internal stress in the long strip profile, avoids the phenomenon of warping, bending or twisting of the hinge connecting piece, and improves the stability of the hinge connecting piece.

[0016] Furthermore, the hot-rolled elongated profile of the hinge connecting piece of the door hinge of the present invention, compared with the existing manufacturing method, has two hinge connecting pieces to be manufactured in the width direction, which can significantly improve the manufacturing efficiency and product quality of the hinge connecting piece. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the manufacturing method of the hinge connecting piece of the car door hinge according to the present invention. Figure 2 This is a schematic diagram of the longitudinal section, i.e., the first section, of the hinge connecting piece to be manufactured according to the present invention; Figure 3 This is a schematic cross-sectional view of the elongated profile used in the manufacturing method of the hinge connecting piece of the car door hinge of the present invention. In the diagram, 1 is the first cross section; 2 is the connecting cross section. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a method for manufacturing a hinge connecting piece for a car door hinge, so as to solve the problems existing in the prior art, eliminate residual stress in the hinge connecting piece, and improve the stability of the hinge connecting piece.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1 to 3 As shown, this embodiment provides a method for manufacturing a hinge connecting piece of a car door hinge, including the following steps: (1) The round steel raw material is cut to obtain the billet required for processing the long strip profile; then the billet is heated by a natural gas furnace and hot rolled into a long strip profile. The direction from the installation end to the hinge end of the hinge connecting piece to be manufactured is the length direction of the hinge connecting piece. The longitudinal section of the hinge connecting piece to be manufactured is the first section 1. The cross section of the long strip profile includes the connecting section 2 and two first sections 1 symmetrically distributed on both sides of the connecting section 2. The first section 1 and the end close to the connecting section 2 are connected to the connecting section 2. The part where the connecting section 2 is located in the long strip profile is the connecting part. (2) Cut the long strip profile along the width direction to obtain the first intermediate profile. The length of the first intermediate profile is an integer multiple of the width of a single hinge connecting piece. (3) The first intermediate profile is transported to the cooling bed for cooling; (4) After the first intermediate profile has cooled, the first intermediate profile is straightened using a straightening machine; (5) Cut off the connecting part in the first intermediate profile to obtain two second intermediate profiles; (6) Cut the second intermediate profile along the width direction to obtain multiple semi-finished products. The length of the semi-finished products is equal to the width of the hinge connecting piece to be obtained. (7) The semi-finished product is finished by using a milling machine; (8) Remove rust from the semi-finished product and then obtain the hinge connecting piece to be manufactured.

[0023] In the optional schemes of this embodiment, the connecting section 2 is preferably rectangular. In practical applications, the connecting section 2 can also be trapezoidal, as long as the connecting section 2 is symmetrical about the center lines of the two first sections 1 in the cross section of the elongated profile.

[0024] In the optional embodiments of this example, a preferred method is to heat the billet to 1180°C using a natural gas furnace before hot rolling. Heating is a gradual process, and the heating time to reach the specified temperature should generally not be less than two and a half hours, with a bright yellow color being ideal. The heating temperature should not be too high, as this will cause internal crystallization changes in the raw material. The temperature should also not be too low, as this will affect subsequent rolling.

[0025] In the optional schemes of this embodiment, it is more preferred that after the first intermediate profile is cooled to 50℃-60℃ in step (4), the first intermediate profile is straightened by a straightening machine. Since the temperature is high and the cooling rate is slow, an air cooler can be used to accelerate the cooling. The cooling temperature and time should be well controlled, and the cooling rate should just meet the requirements of the subsequent straightening process. If the cooling is too slow, the straightening process will take too long, and large deformation will occur after straightening.

[0026] In the optional schemes of this embodiment, it is more preferred that the connecting part is removed by laser cutting equipment in step (5). The laser cutting equipment is a commercially available product known to technicians. The working principle and structure of the laser cutting equipment will not be described in detail in this embodiment. Laser cutting can significantly improve the cutting accuracy.

[0027] In the optional scheme of this embodiment, it is more preferred that the scrap material of the first intermediate profile is removed by laser cutting equipment in step (5).

[0028] In the optional schemes of this embodiment, it is more preferred that the semi-finished product is shot blasted to remove rust in step (8).

[0029] In the optional schemes of this embodiment, it is more preferred that the curvature of the first intermediate profile is ≤ three per thousand after being straightened by the straightening machine. The curvature of the straightened product has a direct impact on the laser cutting and conveying process, and also has a significant impact on the yield of the finished product after cutting.

[0030] In the optional schemes of this embodiment, it is more preferred that the shot blasting treatment time in step (8) is 10 minutes to 18 minutes. If the shot blasting treatment time is too short, the rust removal will not be clean.

[0031] In the optional schemes of this embodiment, the preferred option is to use round steel as the billet. The hot rolling process has 9 hot rolling steps, which causes the billet to gradually undergo plastic deformation to form the above-mentioned long strip profile. The finishing process in step (7) includes milling, grinding and drilling. When milling the edge, attention should be paid to the distance, depth and position. Too large or too small a position is not acceptable, so as to ensure that the final product size meets the requirements.

[0032] The reason for the poor stability of the hinge connecting pieces in existing automotive door hinges is as follows: The thickness of a single hinge connecting piece is often not uniform along its length, but varies in thickness. Furthermore, the thickness of a single hinge connecting piece is asymmetrical along its length. The essence of the hot rolling process is to induce uniform and symmetrical plastic deformation in the metal. Any asymmetry will disrupt this balance. This results in inconsistent flow rates in different thickness areas of the billet during the hot rolling process, creating residual stress inside the product. Consequently, the finished product is prone to warping, bending, or twisting in order to release the internal residual stress.

[0033] In the manufacturing method of the hinge connecting piece of the car door hinge in this embodiment, the cross section of the long strip profile has two symmetrically distributed first sections 1, and the connecting section 2 in the cross section is also a symmetrical structure. This allows the billet to undergo uniform and symmetrical plastic deformation during hot rolling, eliminates the residual internal stress in the long strip profile, avoids the phenomenon of warping, bending or twisting of the hinge connecting piece, and improves the stability of the hinge connecting piece.

[0034] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for manufacturing a hinge connecting piece for a car door hinge, characterized in that, Includes the following steps: (1) The billet is hot-rolled into a long strip profile. The direction from the mounting end to the hinge end of the hinge connecting piece to be manufactured is the length direction of the hinge connecting piece. The longitudinal section of the hinge connecting piece to be manufactured is the first section. The cross section of the long strip profile includes a connecting section and two first sections symmetrically distributed on both sides of the connecting section. The first section is connected to the connecting section at one end close to the connecting section. The part of the long strip profile where the connecting section is located is the connecting part. (2) The long strip profile is cut along the width direction to obtain a first intermediate profile, the length of which is an integer multiple of the width of a single hinge connecting piece; (3) The first intermediate profile is transported to a cooling bed for cooling; (4) After the first intermediate profile has cooled, the first intermediate profile is straightened using a straightening machine; (5) Cut off the connecting portion in the first intermediate profile to obtain two second intermediate profiles; (6) Cut the second intermediate profile along the width direction to obtain a plurality of semi-finished products, the length of the semi-finished products being equal to the width of the hinge connecting piece to be obtained; (7) The semi-finished product is finished by using a milling machine; (8) Remove rust from the semi-finished product to obtain the hinge connecting piece to be manufactured.

2. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: The connecting cross section is rectangular or trapezoidal, and the connecting cross section is symmetrical about the center line of the two first cross sections in the cross section of the elongated profile.

3. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: Before hot rolling the billet, the billet is heated to 1180°C.

4. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: In step (4), after the first intermediate profile is cooled to 50°C-60°C, the first intermediate profile is straightened by a straightening machine.

5. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: In step (5), the connecting portion is removed using a laser cutting device.

6. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 5, characterized in that: In step (5), the scrap material of the first intermediate profile is also removed by the laser cutting equipment.

7. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: In step (8), the semi-finished product is shot blasted to remove rust using a shot blasting machine.

8. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: After the first intermediate profile is straightened by the straightening machine, the curvature of the first intermediate profile is ≤ three per thousand.

9. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 7, characterized in that: The shot blasting treatment in step (8) takes 10 to 18 minutes.

10. The method for manufacturing the hinge connecting piece of the car door hinge according to claim 1, characterized in that: The billet is made of round steel, and the hot rolling process has 9 hot rolling steps; the finishing process in step (7) includes milling, grinding and drilling.

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