Cold extrusion process for a door closer internal tooth piston

Abstract

The application discloses a cold extrusion process of an inner-tooth piston of a door closer, and particularly relates to the technical field of the cold extrusion of the door closer. The cold extrusion process of the door closer piston comprises the following steps: S1, preliminary preparation, uniformly cutting steel materials into segments according to required weights by using a punch; S2, preliminary model, extruding a preliminary model to form a round head, a flat head and a shallow groove in the middle; S3, extrusion and stretching, integrally stretching the blank by extrusion and stretching, and extruding a bone groove at the bottom; S4, extrusion and stretching again, inversely extruding the lower section of the blank by using a die; S5, diameter reduction, extruding the upper section of the blank by using a die; S6, machining, milling the two sides of the blank into flat edges and digging a hole in the middle; and S7, broach forming, forming a through hole into a required shape by using a broach. The cold extrusion process of the door closer piston improves processing efficiency, reduces material waste, and lowers machining cost by multiple cold extrusion and stretching of the blank. Moreover, the cold extrusion process can make the compactness and physical properties of the final product better.

Description

Technical Field

[0001] This invention relates to the field of cold extrusion technology for door closers, specifically a cold extrusion process for an internal tooth piston of a door closer. Background Technology

[0002] A door closer, also known as a modern hydraulic door closer, is a spring-like hydraulic device mounted on top of the door. The door closer operates by moving a linkage through the door, which in turn rotates a gear that drives a rack on the door closer piston. The piston moves to the right, compressing the spring and storing energy. When the external force is released, the spring releases the energy, pushing the piston in the opposite direction. The piston then pushes the gear in the opposite direction, thus closing the door. The traditional manufacturing process for a door closer piston involves: selecting a steel billet, forging it into a piston blank according to requirements, and then performing multiple rough turning operations on the outer diameter, top surface, CNC milling, and broaching. This traditional manufacturing process is complex, wasteful of raw materials, and suffers from long processing times and dimensional inaccuracies. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a cold extrusion process for the internal tooth piston of a door closer, which solves the problems of material waste, complex processes, long forging time, and dimensional deviations associated with traditional piston machining through fine and rough turning.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a cold extrusion process for an internal tooth piston of a door closer, specifically including the following steps:

[0005] S1. Preliminary preparation: spheroidize and anneal the steel, then use a punch press to cut the steel into uniform segments according to the required weight, and then clean, phosphate, and saponify it.

[0006] S2. Preliminary forming: The steel cut into sections in S1 is placed into a cold extrusion device, and the lower section of the steel is extruded into an elliptical cylinder and the upper section is extruded into a cylinder. At the same time, a directional concave hole is extruded at the center of the top circle of the upper section to form the initial blank.

[0007] S3. Extrusion and stretching: The top of the extrusion die in the cold extrusion die is a concentric circle with a flat part. The die is used to press the blank top concave hole, so that the blank top concave hole also has a flat part and the inside of the concave hole is hollow. The blank is stretched as a whole. Then the bottom of the blank is extruded. The bottom is pressed out by the ejector pin to form a bone groove. The bone groove is perpendicular to the major axis of the elliptical cylinder section.

[0008] S4. Extrusion and stretching: Using the bone groove to set the angle, the mold is used to back-extrude the solid part of the lower section of the blank, expanding this section from an elliptical cylinder into a cylindrical shape. The outer diameter of the cylinder is the grinding outer diameter required for this product. While expanding, the blank is further stretched.

[0009] S5, diameter reduction: the upper section of the blank is extruded with a mold to reduce its outer diameter to the above-mentioned grinding outer diameter. The top inner hole is freely formed and its diameter is less than 12mm, which is reserved for the subsequent installation of a one-way valve.

[0010] S6. Machining: Using a CNC milling machine, the two sides of the blank elliptical cylindrical section are milled into flat edges and a hole is drilled in the middle. The hole is machined into the shape required by the broach.

[0011] S7. Broaching: Use a broach to draw the hole formed in step 6 into the required shape.

[0012] Preferably, in step S2, the lower section of the blank is elliptical cylindrical with an outer diameter smaller than that of the upper end, in order to reduce the amount of material used and the amount of cutting in subsequent processes.

[0013] Preferably, in step S3, the shape of the top of the extruded blank is a concentric circle with a flat section, and the inner hole of the top of the extruded blank is also a concentric circle with a flat section and the flat section is perpendicular to the major axis of the elliptical cylinder section. The bottom bone groove is perpendicular to the major axis of the elliptical cylinder section, which facilitates the orientation of the machining in step S6.

[0014] Preferably, the blank formed in step S4 is cylindrical at both ends and elliptical in the middle, with a circular inner hole at the top having a flat section that is perpendicular to the major axis of the elliptical cylinder cross-section.

[0015] Preferably, the inner hole at the top of the blank in step S5 is freely formed, and the diameter of the top circle of the upper section of the blank in step S5 must be less than 12mm.

[0016] Preferably, in steps S1-S5, the blank is extruded using a cold extrusion device in conjunction with multiple molds to obtain the final shape, or multiple molds are installed on a multi-station cold heading machine to achieve multi-station cold heading, which will result in higher production efficiency.

[0017] This invention provides a cold extrusion process for the internal tooth piston of a door closer, which has the following advantages compared with existing processes:

[0018] The cold extrusion process of the internal tooth piston of the door closer, through multiple cold extrusions and stretching of the blank to finally form it, can improve processing efficiency, reduce material waste, reduce machining costs, and the cold extrusion process can make the final product denser and have better physical properties. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of the initial forming process of the cold extrusion process of the present invention;

[0020] Figure 2 This is a schematic cross-sectional view of the initial forming process of the cold extrusion process of the present invention.

[0021] Figure 3This is a three-dimensional schematic diagram of the cold extrusion stretching process of the present invention.

[0022] Figure 4 This is a schematic cross-sectional view of the cold extrusion stretching process of the present invention;

[0023] Figure 5 This is a schematic cross-sectional view of the cold extrusion and re-stretching process of the present invention;

[0024] Figure 6 This is a cross-sectional schematic diagram of the diameter reduction process in the cold extrusion process of the present invention;

[0025] Figure 7 This is a three-dimensional schematic diagram of the cold extrusion machining process of the present invention;

[0026] Figure 8 This is a three-dimensional schematic diagram of the cold extrusion process for broach forming according to the present invention. Detailed Implementation

[0027] The technical processes described in the embodiments of the present invention are clearly and completely explained. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a technical solution: a cold extrusion process for the internal tooth piston of a door closer, specifically including the following steps:

[0029] S1. Preliminary preparation: spheroidize and anneal the steel, then use a punch press to cut the steel into uniform segments according to the required weight, and then clean, phosphate, and saponify it.

[0030] S2. Preliminary Forming: The steel segments cut in S1 are placed into a cold extrusion apparatus. The lower segment is extruded into an elliptical cylinder, and the upper segment into a cylindrical shape. Simultaneously, a directional concave hole is extruded at the center of the top of the upper segment, forming the initial blank. For details, please refer to [link to relevant documentation]. Figure 1-2 ;

[0031] S3. Extrusion and stretching: The extrusion die in the cold extrusion mold has a concentric circular top with a flattened portion. This die is used to reverse-extrude the concave hole on the top of the blank, causing the concave hole to also have a flattened portion and become hollow inside. The blank is stretched as a whole. Then, the bottom of the blank is extruded, and a groove is pressed into the bottom by the ejector pin. The groove is perpendicular to the major axis of the elliptical cylinder section. For details, please refer to [link to details]. Figure 3-4 ;

[0032] S4. Extrusion and stretching: Using the rib groove to set the angle, the solid part of the lower section of the blank is extruded using a mold, expanding this section from an elliptical cylinder into a cylindrical shape. The outer diameter of the cylinder is the grinding outer diameter required for this product. During the expansion, the blank is further stretched. For details, please refer to [link / reference]. Figure 5 ;

[0033] S5. Diameter Reduction: The upper section of the blank is extruded using a die to reduce its outer diameter to the aforementioned ground outer diameter. The top inner hole is freely formed with a diameter less than 12mm, reserving a position for the subsequent installation of a one-way valve. For details, please refer to [link / reference needed]. Figure 6 ;

[0034] S6. Machining: Using a CNC milling machine, the two sides of the elliptical cylindrical blank are milled into flat edges, and a hole is drilled in the middle. The hole is then machined into the shape required for the broach. For details, please refer to [link / reference]. Figure 7 ;

[0035] S7. Broaching: Use a broach to draw the hole formed in step 6 into the desired shape. For details, please refer to [link / reference]. Figure 8 .

[0036] Preferably, the blank formed in step S4 is cylindrical at both ends and elliptical in the middle, with a circular inner hole at the top having a flat section that is perpendicular to the major axis of the elliptical cylinder cross-section.

[0037] Preferably, the inner hole at the top of the blank in step S5 is freely formed, and the diameter of the top circle of the upper section of the blank in step S5 must be less than 12mm.

[0038] Preferably, in steps S1-S5, the blank is extruded using a cold extrusion device in conjunction with multiple molds to obtain the final shape, or multiple molds are installed on a multi-station cold heading machine to achieve multi-station cold heading, which will result in higher production efficiency.

[0039] The cold extrusion process for the door closer piston, through multiple cold extrusions and stretching of the blank to finally form it, can improve processing efficiency, reduce material waste, lower machining costs, and the cold extrusion process can make the final product denser and have better physical properties.

[0040] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

Claims

1. A cold extrusion process for an internal tooth piston of a door closer, characterized in that, Specifically, the following steps are included: S1. Preliminary preparation: spheroidize and anneal the steel, then use a punch press to cut the steel into uniform segments according to the required weight, and then clean, phosphate, and saponify it. S2. Preliminary forming: The steel cut into sections in S1 is placed into a cold extrusion device, and the lower section of the steel is extruded into an elliptical cylinder and the upper section is extruded into a cylindrical shape. At the same time, a directional concave hole is extruded at the center of the top circle of the upper section to form an initial blank. The lower section of the blank is elliptical cylinder, and its outer diameter is smaller than that of the upper end. S3. Extrusion and stretching: The top of the extrusion die in the cold extrusion mold is a concentric circle with a flat part. The die is used to press the top concave hole of the blank, so that the top concave hole of the blank also has a flat part and the inside of the concave hole is hollow. The blank is stretched as a whole. Then the bottom of the blank is extruded. The bottom is pressed out by the ejector pin to form a bone groove. The flat part of the top of the extrusion die, the flat part of the inner hole of the top of the blank, and the direction of the bottom bone groove are all perpendicular to the major axis of the elliptical cylinder section. S4. Extrusion and stretching: Using the bone groove to set the angle, the mold is used to back-extrude the solid part of the lower section of the blank, expanding this section from an elliptical cylinder into a cylindrical shape. The outer diameter of the cylinder is the grinding outer diameter required for this product. While expanding, the blank is further stretched. S5. Reduction of diameter: The upper section of the blank is extruded with a mold to reduce its outer diameter to the above-mentioned grinding outer diameter. The top inner hole is freely formed and its diameter is less than 12mm, which is reserved for the subsequent installation of a one-way valve. S6. Machining: Using a CNC milling machine, the two sides of the blank elliptical cylindrical section are milled into flat edges and a hole is drilled in the middle. The hole is machined into the shape required by the broach. S7. Broaching: Use a broach to shape the hole formed in step 6 into the required shape.

Images