Floating type reverse extrusion forming die

Abstract

The invention relates to a floating back-extrusion molding formwork which is characterized in that a floating air cylinder body is fixed with a lower module by a bolt, a fixed ring-shaped cushion block is arranged in the middle of the floating air cylinder body, the lower part of the fixed ring-shaped cushion block is fixed with the lower module by the bolt, a piston of the floating air cylinder is arranged outside the fixed ring-shaped cushion block, a molding cushion block is arranged at the upper end of the fixed ring-shaped cushion block, a cushion block of a floating concave mold is arranged at the upper end of the fixed ring-shaped cushion block, the floating concave mold is arranged at the upper end of the cushion block of the floating concave mold, a floating and guiding sleeve frame is arranged at the upper end of the floating concave mold and connected with the upper molding formwork by the floating and guiding sleeve, an outer mold is arranged outside the floating concave mold and the cushion block of the floating concave mold, and one side of the floating air cylinder is provided with an air inlet hole. The formwork has the advantages of prolonging the service life of a punch, causing the realization of the possibility that the ratio between the depth and the diameter of the inner hole of the one-way back-extrusion is more than 5, improving the inner quality of a work piece, ensuring the strength of the work piece, saving material and reducing the processing cost.

Description

technical field [0001] The invention relates to a floating back-extrusion forming mold base, which can be used for various types of gasoline and diesel engines, and belongs to the technical field of cold forging precision forming. Background technique [0002] Piston pin is an important part in gasoline and diesel engines, which plays a role in connecting the connecting rod and piston of the engine. When the engine is working, the high-speed reciprocating motion of the piston in the cylinder is transmitted to the connecting rod through the piston pin, and converted into high-speed rotary motion. Because the force transmitted is very large during work, and it is also under long-term and continuous variable bending stress Among them, the stress state is very complicated, so the working environment is very harsh. [0003] Generally, the piston pin is designed as a hollow cylinder, and the manufacturing processes usually used are as follows: [0004] 1. Bar drilling: This proc...

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Problems solved by technology

[0004] 1. Bar drilling: This process is characterized by high material consumption, poor inner hole roughness, low damage limit of the product, low production efficiency, and cannot be used in mass production;

[0005] 2. Pipe processing: This process is suitable for mass production, but due to the difficulty in forming small-diameter thick-walled pipes, and most of them are low-carbon steel pipes, it can only be used for some engines with low life expectancy and short continuous working time , such as lawn mowers, etc.;

[0007] like figure 1 As shown, it is a die formed by cold forging two-way bar extrusion, including punch 1, fixed seat 2, fixed ring 3, guide sleeve 4, die 6, lower ejector rod 7, cushion block 8 and gasket block 9 , the gasket block 9 is arranged at the bottom of the gasket block 8, the die 6 is arranged at the upper end of the gasket block 8, the lower ejector rod 7 is arranged in the die 6 and the gasket block 8, and its lower end is in contact with the gasket block 9, and the guide sleeve 4 is set on the upper end of the die 6, the fixed seat 2 is set in the guide sleeve 4, and its upper end is connected with the extruder through the fixed ring 3, and the punch 1 is set in the fixed seat 2. When working, put the workpiece 5 into the concave In the mold 6, when extruding, the punch of the extruder punches the punch 1 into the workpiece 5 to extrude half of the workpiece 5, and then turns the workpiece 5 and extrudes it again. figure 2 The piston pin 10, the processing disadvantages of this mold are: 1. Since the die 6 is fixed, when the punch is pressed down, the friction force when the workpiece 5 is squeezed up and flows is very large, and the depth of extrusion It can only be squeezed to a depth of 1:2.5-1:3. If it is to be punched to a depth of more than 1:5, the punch will bend or even break

[0008] 2. Due to the cold forging bidirectional bar extrusion molding, a continuous skin 11 is formed in the middle of the piston pin 11 after bidirectional extrusion, and the continuous skin 11 is processed by punching or drilling in subsequent processing Removal, because the continuous metal flow line formed in the extrusion process is cut off during the removal process of the continuous skin 11, and the position of the continuous skin 11 is often in the middle, and this is where the reciprocating motion of the piston pin bears variable bending stress center point, resulting in a weak point of product strength

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