CN105880304A - Cold extruding forming method used for automotive spline sleeve part - Google Patents

Abstract

The invention relates to a cold extruding forming method used for an automotive spline sleeve part. The spline sleeve is in an axisymmetrical cylinder shape. Axial involute spline tooth are formed in the inner surface of the body of a cylinder and the outer surface of the body of the cylinder. The end surfaces of outer spline tooth are in an arc shape. The method comprises the following steps: (1) preparing billets of the spline sleeve part; (2) annealing the billets to soften the billets; (3) conducting slot blasting treatment of the annealed billets to remove burrs and scale; (4) conducting lubricating treatment of the billets which is subjected to the slot blasting treatment; (5) conducting extruding and forming treatment of the billets which is treated by step (4) to make inner spline tooth and the outer spline tooth be extruded and formed all at once; (6) forming the arc-shaped end surfaces of the outer spline tooth by using a back pressure device. Compared with the prior art, the spline sleeve part produced by utilizing the cold extruding forming method has the advantages that the mechanical property is good, the material utilization rate is high, the defect that tooth-shaped die cavity can not be fully filled can be avoided and the production process flow is short.

Description

A cold extrusion forming method of spline sleeve parts for vehicles

technical field

The invention relates to the technical field of plastic processing of metal materials, in particular to a cold extrusion forming method of a spline sleeve part for a vehicle.

Background technique

Splines are widely used in various transmission systems due to their advantages of ensuring a constant transmission ratio, wide range of transmission efficiency, high efficiency, and long life. The density, hardness and performance of spline teeth are closely related to the production process. At present, there are three common forming methods for such parts: one is cutting processing, the other is powder metallurgy technology die-casting, and the third is plastic forming.

When the spline teeth are processed by cutting, the fibers of the tooth-shaped part are cut off by the broach, which reduces the strength of the spline and affects its load-carrying capacity, and the material utilization rate is low, the working cycle is long, and the production cost is high. Facing fierce market competition , the traditional method of cutting splines is becoming more and more stretched. The second method is powder metallurgy forming. Although powder metallurgy technology can be used to realize the industrialization of some spline parts, this method is to press the metal powder into the shape of the required parts and then sinter them at high temperature. , In this process, the metal material is not rolled to form a metal fiber flow, which is a non-oriented mechanical property, which makes the structure density of the powder metallurgy tooth profile poor, and the bending and shearing strengths are not ideal. In addition, the precise dimensions of spline parts formed by high-temperature sintering are difficult to control, and the surface roughness of the spline teeth is large, which makes it difficult to meet the expected quality requirements.

Extrusion technology, which is widely used at present, realizes forming by controlling the flow of metal through the mold cavity, so as to manufacture metal parts of different shapes, sizes and mechanical properties. Extrusion forming technology can ensure that the flow of metal fibers is not cut off, and the cold hardening characteristics of metal can be used to improve the strength of formed parts, so that the bearing capacity, safety and service life of parts are improved. According to the law of least resistance in plastic forming, it can be known that when the punch exerts pressure on the metal blank placed in the die, the metal flows upward and downward, and the deformed metal flows preferentially to the part with the least resistance, and the fast-flowing metal flows first. Because the slow-flowing metal contacts the ejector rod; therefore, when the spline sleeve is formed by the ordinary extrusion method, because the metal at the end of the cylinder flows faster than the metal at the spline teeth, mold is prone to appear at the tooth profile The cavity is not filled enough to cause defects, so that the products produced cannot meet the design requirements.

Contents of the invention

The object of the present invention is to provide a cold extrusion forming method of a vehicle spline sleeve part with good mechanical properties and low manufacturing cost in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

A method for cold extrusion forming of spline sleeve parts for vehicles. The spline sleeve is in the shape of an axisymmetric cylinder, and axial involute spline teeth are arranged on the inner and outer surfaces of the cylinder. The end faces of the spline teeth are arc-shaped, and the method includes the following steps:

(1) Prepare the blank of the spline sleeve part;

(2) annealing the blank to soften it;

(3) Shot blasting the annealed blank to eliminate burrs and scales;

(4) Lubricate the blank after shot blasting;

(5) pressing the billet processed in step (4), so that the inner and outer spline teeth are extruded at one time;

(6) The back pressure device is used to shape the end face of the outer spline into an arc shape.

The technological conditions for annealing the blank in step (2) are: under the protection of nitrogen atmosphere, keep the temperature at 860-950°C for 5-9 hours, and then cool down to below 450°C with the furnace and leave the furnace.

The technical conditions for shot blasting the annealed blank in step (3) are: use pellets with a diameter of 0.5-1.0 mm to treat for 10-30 minutes, so that the surface of the blank is free of scale and the surface of the rust is bright and even in color.

In step (4), the process conditions for lubricating the blank after shot blasting include the following steps in turn: degreasing for 5-10 minutes, cold water washing for 0.5-2 minutes, hot water washing for 0.5-2 minutes, pickling for 5-10 minutes, Cold water washing for 0.5-2 minutes, hot water washing for 0.5-2 minutes, phosphating for 10-20 minutes, cold water washing for 0.5-2 minutes, hot water washing for 0.5-2 minutes, saponification for 3-10 minutes, dehydration and drying for 2-15 minutes.

The technological conditions for pressing the billet in step (5) are as follows: installing a forming die on a cold extrusion machine for extrusion, applying a pressure of 2-10Kg/cm ² and a speed of 30-60spm.

In step (5), the shape, structure and size of the spline sleeve are matched with the shape, structure and size of the mold used for one-time extrusion molding of the inner and outer spline teeth. The spline teeth extruded by this method have a wide forming area, which can not only form the full teeth through the sleeve, but also form the partial teeth on the sleeve. This extrusion process can prepare a type of spline shaft with axisymmetric structure. Sets are not limited to a single form.

In step (6), the back pressure damping force is used for closed forming, that is, a reverse pressure is applied to the end of the formed tooth shape outside the spline sleeve, the back pressure is 2-10Kg/cm ² , and the pressure application time is 2-5S. Specifically, using the back pressure generated by the pressure oil (gas) in the lower chamber of the piston of the hydraulic (air) cylinder in the back pressure device, a reverse force is applied to the end of the cylinder to slow down the metal flow rate at this part and suppress this The metal flows in the part, and the resistance of the metal with the slow flow rate in the original tooth-shaped part is relatively reduced, and the flow rate is accelerated, so that the metal flow rate tends to be consistent as a whole. The size of the back pressure is adjusted by the overflow valve. After the extrusion is completed, the upper mold returns with the slider of the press, and the lower chamber of the piston of the hydraulic (gas) cylinder passes pressure oil (gas) to move the lower plunger of the piston upward. The spline sleeve is ejected from the die. The back pressure device is used to fully fill the mold with the metal on the end face of the outer spline tooth, forming a circular arc shape, which solves the problem that the mold cavity is not filled at the tooth shape, which causes defects and the product does not meet the design requirements.

Compared with the prior art, the invention adopts the cold extrusion technology to form the inner and outer teeth of the spline sleeve at one time, and combines the back pressure device to realize the forming of the arc-shaped tooth end. Compared with the traditional method of processing spline teeth by broaching, this forming method has high material utilization rate, short production cycle, and good mechanical properties of parts; it avoids the disadvantages of large equipment tonnage, poor structure density, and large surface roughness required by powder metallurgy gears. ; Solve the problem of dissatisfaction with the metal mold filling at the arc tooth end.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Fig. 2 is the structural representation of extrusion mold of the present invention;

Numbers in the figure: 1 is a punch, 2 is a punch cover, 3 is a die, 4 is a blank, 5 is an outer ring of a die, 6 is a pressure ring of a die, 7 is a back pressure device, and 8 is a lower ejector pin.

Fig. 3 is the vehicle spline sleeve part structural representation that embodiment 1 makes;

Fig. 4 is the vehicle spline sleeve part structural representation that embodiment 2 makes;

Fig. 5 is a schematic diagram of the structure of the vehicle spline sleeve parts obtained in Example 3.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1

A cold extrusion forming method for spline sleeve parts for vehicles, the part structure is shown in Figure 3, and the forming process is shown in Figure 1, including blanking, annealing, shot blasting, lubrication treatment, and one-time extrusion forming of internal and external teeth , back pressure device forming circular arc tooth end and other processes, the specific steps are as follows:

(1) Prepare the spline sleeve blank;

(2) Annealing to soften the blank; the process conditions are: under the protection of nitrogen atmosphere, heat preservation at 860°C for 8 hours, and then cool with the furnace to below 450°C;

(3) Shot blasting treatment to eliminate burrs and oxide scales on the surface of the blank (shot blasting):

The process conditions are: use pellets with a diameter of 0.6-1.0mm to treat for 10 minutes, so that the surface of the blank has no scale and the surface of the rust is bright and uniform;

(4) Lubricate the blank;

The process conditions include the following steps in turn: degreasing for 5 minutes, cold water washing for 0.5 minutes, hot water washing for 0.5 minutes, pickling for 5 minutes, cold water washing for 0.5 minutes, hot water washing for 0.5 minutes, phosphating for 10 minutes, cold water washing for 0.5 minutes, and hot water washing for 0.5 minutes , saponification for 3 minutes, dehydration and drying for 2 minutes;

(5) Place the blank in the forming mold, and use the mold to extrude the inner and outer spline teeth at one time; Mold cover 2, the die pressure ring 6 and the outer ring 5 of the die are arranged in sequence on the outside of the die 3, the blank 4 is placed in the die 3, the punch 1 cooperates with the die 3 for extrusion forming, and the die is placed under the die 3 A back pressure device 7 that supports the blank 4 and carries out back pressure extrusion on the blank 4 is provided, and a lower ejector rod 8 that ejects the spline sleeve from the die is provided in the back pressure device 7;

The process conditions are as follows: install a die on the LIC400 cold extrusion machine for extrusion, the applied pressure is 4Kg/cm ² , and the speed is 30spm;

(6) Use a back pressure device to apply a back pressure damping force on the end of the cylinder, that is, apply a reverse pressure to the end of the formed tooth outside the spline sleeve. The back pressure is 2Kg/cm ² , and the pressure time is 5S. Part metal flows, so that the metal at the outer tooth end fully fills the mold and forms an arc shape.

(7) Machining to prepare the final spline sleeve parts.

The above-mentioned extrusion method is used to produce the parts of the spline shaft sleeve for the vehicle, as shown in Figure 3, which improves the material utilization rate, improves the production efficiency, improves the mechanical properties of the parts, meets the requirements of "green manufacturing", and has good social benefits .

Example 2

A cold extrusion forming method for a vehicle spline sleeve part, the part structure is shown in Figure 4, and the forming process specifically includes the following steps:

(1) Prepare blank;

(2) Annealing and softening;

The process conditions are: under the protection of nitrogen atmosphere, heat preservation at 880°C for 7 hours, and then cool down to below 450°C with the furnace;

(3) Shot blasting treatment;

The process conditions are: use pellets with a diameter of 0.6-1.0mm to treat for 18 minutes, so that the surface of the blank has no scale and the surface of the rust is bright and uniform;

(4) Lubrication treatment;

The process conditions include the following steps in turn: degreasing for 7 minutes, cold water washing for 0.8 minutes, hot water washing for 0.8 minutes, pickling for 8 minutes, cold water washing for 0.8 minutes, hot water washing for 0.8 minutes, phosphating for 12 minutes, cold water washing for 0.8 minutes, and hot water washing for 0.8 minutes , saponification for 4 minutes, dehydration and drying for 6 minutes;

(5) the blank is placed in the forming die, the forming die is shown in Figure 2, and the inner and outer teeth are extruded at one time;

The process conditions are as follows: install a die on the LIC400 cold extrusion machine for extrusion, the applied pressure is 5Kg/cm ² , and the speed is 40spm;

(6) Use a back pressure device to apply a back pressure damping force on the end of the cylinder, that is, apply a reverse pressure to the end of the formed tooth outside the spline sleeve. The back pressure is 5.0Kg/cm ² , and the pressure time is 3S. The metal flows in this part, so that the metal at the outer tooth end is fully filled and formed into an arc shape.

(7) Machining the blank that already has a tooth shape to prepare a spline sleeve part.

The spline shaft sleeve parts produced by this technology have high material utilization rate, short production cycle and good mechanical properties of the parts, which can well meet the market demand and bring huge economic value to the enterprise.

Example 3

A cold extrusion forming method for a vehicle spline sleeve part, the part structure is shown in Figure 5, and the forming method specifically includes the following steps:

(1) Blanking;

(2) Annealing;

The process conditions are: under the protection of nitrogen atmosphere, heat preservation at 900°C for 7 hours, and then cool to below 450°C with the furnace;

(3) shot blasting;

The process conditions are: use pellets with a diameter of 0.6-1.0mm to treat for 25 minutes, so that the surface of the blank has no scale and the surface of the rust is bright and uniform;

(4) lubrication;

The process conditions include the following steps in turn: degreasing for 10 minutes, cold water washing for 1 minute, hot water washing for 1 minute, pickling for 10 minutes, cold water washing for 1 minute, hot water washing for 1 minute, phosphating for 15 minutes, cold water washing for 1 minute, hot water washing for 1 minute , Saponification for 5 minutes, dehydration and drying for 10 minutes;

(5) Place the blank in the forming mold for one-time cold extrusion of the inner and outer spline teeth;

(6) Use a back pressure device to apply a back pressure damping force on the end of the cylinder, that is, apply a reverse pressure to the end of the formed tooth outside the spline sleeve. The back pressure is 10Kg/cm ² , and the pressure time is 2S. Part metal flows, so that the metal at the outer tooth end fully fills the mold and forms an arc shape.

The process conditions are as follows: install a die on the LIC400 cold extrusion machine for extrusion, the applied pressure is 6Kg/cm ² , and the speed is 50spm;

(7) Machining the formed parts to prepare spline sleeve parts.

The above descriptions of the embodiments are for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (7)

1. A cold extrusion forming method of a spline sleeve part for a vehicle, the spline sleeve is an axisymmetric cylinder, and axial involute spline teeth are provided on the inner and outer surfaces of the cylinder , the end faces of the external spline teeth are arc-shaped, characterized in that the method includes the following steps: (1) Prepare the blank of the spline sleeve part; (2) annealing the blank to soften it; (3) Shot blasting the annealed blank to eliminate burrs and scales; (4) Lubricate the blank after shot blasting; (5) pressing the billet processed in step (4), so that the inner and outer spline tooth parts are extruded once; (6) The back pressure device is used to shape the end face of the outer spline into an arc shape. 2. The cold extrusion forming method of a spline sleeve part for a vehicle according to claim 1, wherein the process conditions for annealing the blank in step (2) are: under the protection of a nitrogen atmosphere, at 860 Insulate at -950°C for 5-9 hours, then cool down to below 450°C with the furnace. 3. the cold extrusion forming method of a kind of vehicle spline sleeve part according to claim 1, it is characterized in that, in the step (3), the processing condition that the rough blank after the annealing is carried out shot blasting is: use diameter as 0.5-1.0mm pellets are subjected to shot blasting for 10-30 minutes to remove scale and rust on the surface of the blank, so that the surface of the parts is smooth, bright and even in color. 4. the cold extrusion forming method of a kind of vehicle spline sleeve part according to claim 1, it is characterized in that in step (4) the rough blank after shot blasting is carried out the processing condition of lubricating treatment, comprise following successively Steps: degreasing for 5-10 minutes, cold water washing for 0.5-2 minutes, hot water washing for 0.5-2 minutes, pickling for 5-10 minutes, cold water washing for 0.5-2 minutes, hot water washing for 0.5-2 minutes, phosphating for 10-20 minutes, Wash in cold water for 0.5-2 minutes, wash in hot water for 0.5-2 minutes, saponify for 3-10 minutes, dehydrate and dry for 2-15 minutes. 5. The cold extrusion forming method of a spline sleeve part for a vehicle according to claim 1, characterized in that, the process condition for pressing the blank in step (5) is: installing and forming on a cold extrusion machine The die is extruded, the applied pressure is 2-10Kg/cm ² , and the speed is 30-60spm. 6. The cold extrusion forming method of a spline sleeve part for a vehicle according to claim 1, characterized in that, the forming die and the spline selected during the primary extrusion molding of the inner and outer spline tooth positions in step (5) The shape, structure and size of the key cover match. 7. The cold extrusion forming method of a spline sleeve part for a vehicle according to claim 1, characterized in that, in step (6), the back pressure damping force is used for closed forming, that is, the spline sleeve has been formed outside the spline sleeve. Reverse pressure is applied to the end of the forming tooth shape, the back pressure is 2-10Kg/cm ² , and the pressure time is 2-5S, so that the resistance of the fast-flowing part of the material is increased, the flow is restrained, and the slow-flowing part of the material is fully filled. , so that the end of the tooth shape is consistent.