A combined die for extruding two-section spline

Abstract

The utility model provides a kind of for extruding two-section spline's combined die, including first mould core, second mould core and positioning pin, and the first mould core and second mould core are fixedly connected by positioning pin;Multiple first inner spline tooth blocks and second inner spline tooth blocks are respectively fixedly arranged with interval in the first mould core and second mould core, the tooth top of the first inner spline tooth block is sequentially provided with import face, first mould face, first forming surface and first export face, and the tooth top of the second inner spline tooth block is sequentially provided with second mould face, second forming surface and second export face.The utility model can be realized on the hollow shaft class and pipe class transmission system parts of automobile by cold extrusion forming two-section spline once processing, and cold extrusion process precision is high, and processing cost is low.

Description

Technical Field

[0001] This utility model relates to the field of cold extrusion forming die technology, and in particular to a combined die for extruding two-section splines. Background Technology

[0002] Spline drives are a common type of transmission in automotive parts, characterized by multi-tooth operation, high load-bearing capacity, good centering, good guiding properties, and low stress concentration, making them widely used. Common machining methods for splines include gear hobbing, gear rolling, gear milling, and cold extrusion forming. Generally speaking, cold extruded splines are characterized by low cost and high precision, and are widely used in the machining of automotive shaft and tubular transmission system parts.

[0003] Currently, it is impossible to machine two-section splines in a single step using cold extrusion for hollow shaft and tubular transmission system parts in automobiles. While gear rolling and milling can produce two-section splines, the required precision is insufficient and the cost is too high. To meet the demand for machining two-section splines in a single step while retaining the advantages of high precision and low cost, cold extrusion technology has become a challenging technology to achieve this. Utility Model Content

[0004] The present invention aims to provide a combination mold for extruding two-section splines, so as to realize the cold extrusion forming of two-section splines for automotive hollow shaft and tubular transmission system parts in one step. The cold extrusion process has high precision and low processing cost.

[0005] Therefore, the technical solution adopted by this utility model is as follows: a combined mold for extruding two-section splines, including a first mold core, a second mold core, and a positioning pin, wherein the first mold core and the second mold core are fixedly connected by the positioning pin; multiple first internal spline tooth blocks and second internal spline tooth blocks are fixedly arranged at intervals in the first mold core and the second mold core respectively, wherein the tooth top of the first internal spline tooth block is sequentially provided with an inlet surface, a first mold entry surface, a first forming surface, and a first outlet surface, and the tooth top of the second internal spline tooth block is sequentially provided with a second mold entry surface, a second forming surface, and a second outlet surface; the multiple inlet surfaces, first mold entry surfaces, first forming surfaces, and first outlet surfaces are all evenly spaced around the center line of the first mold core, and respectively form an inlet surface area, a first mold entry surface area, a first forming surface area, and a first outlet surface area; the multiple second mold entry surfaces, second forming surfaces, and second outlet surfaces are all evenly spaced around the center line of the second mold core, and respectively form a second mold entry surface area, a second forming surface area, and a second outlet surface area.

[0006] As a preferred embodiment of the above scheme, the angles between the inlet surface, the first mold entry surface, the first forming surface, and the first outlet surface and the center line of the first mold core are 28°-32°, 18°-20°, 0°, and 5°-7°, respectively.

[0007] More preferably, the angles between the second mold entry surface, the second forming surface, and the second exit surface and the center line of the second mold core are 9°-11°, 0°, and 5°-7°, respectively.

[0008] More preferably, the lengths of the inlet surface, the first mold entry surface, and the first forming surface are 5.7mm-5.9mm, 3.1mm-3.3mm, and 2.4mm-2.6mm, respectively.

[0009] More preferably, the lengths of the second mold entry surface and the second forming surface are 9.55mm-9.95mm and 2.9mm-3.1mm, respectively.

[0010] The beneficial effects of this utility model are as follows: by using the first mold core, the second mold core, and the positioning pin, two-section splines can be processed in one step on hollow shaft and tubular transmission system parts of automobiles through cold extrusion forming. The cold extrusion process has high precision and the processing cost of two-section splines is low. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of this utility model.

[0012] Figure 2 yes Figure 1 A sectional view. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0014] like Figure 1-2 As shown, a combined mold for extruding two-section splines includes a first mold core 1, a second mold core 4, and a positioning pin 2. The first mold core 1 and the second mold core 4 are fixedly connected by the positioning pin 2. Multiple first internal spline tooth blocks 3 and second internal spline tooth blocks are respectively fixedly arranged at intervals within the first mold core 1 and the second mold core 4. The tooth tips of the first internal spline tooth blocks 3 are sequentially provided with an inlet surface 11, a first mold entry surface 12, a first forming surface 13, and a first outlet surface 14. The tooth tips of the second internal spline tooth blocks are sequentially provided with a second mold entry surface 7, a second forming surface 6, and a second outlet surface 5. Multiple inlet surfaces 11, first mold entry surfaces 12, first molding surfaces 13, and first outlet surfaces 14 are all evenly spaced around the center line of the first mold core 1, forming an inlet surface region 18, a first mold entry surface region 17, a first molding surface region 16, and a first outlet surface region 15, respectively. Multiple second mold entry surfaces 7, second molding surfaces 6, and second outlet surfaces 5 are all evenly spaced around the center line of the second mold core 4, forming a second mold entry surface region 10, a second molding surface region 9, and a second outlet surface region 8, respectively.

[0015] The first mold core 1 and the second mold core 4 are respectively provided with a first positioning pin hole and a second positioning pin hole. The positioning pin 2 is inserted into the first positioning pin hole and the second positioning pin hole to realize the fixed connection between the first mold core 1 and the second mold core 4 and to ensure the concentricity of the two mold cores.

[0016] During cold extrusion processing, the first die core 1 and the second die core 4 are fixedly connected together and then embedded in the die base. The die base is fixedly installed on the machine tool. The tube moves along the center line of the first die core 1. Then the tube enters the first die entry area 17 through the guide surface area 18. In the first die entry area 17, the tube contacts multiple first die entry surfaces 12 and is pre-extruded. Then it enters the first forming surface area 16 and contacts multiple first forming surfaces 13. The first spline is precisely cold-extruded and forms a first spline segment on the tube. Then the tube continues to be fed to the second die entry area 10 of the second die core 4 and then enters the second forming surface area 9 and contacts the second forming surface 6. The first spline on the tube is precisely cold-extruded into a second spline and forms a second spline segment on the tube. At this time, the tube part located in the first die core 1 is precisely cold-extruded into the first spline after passing through the first forming surface area 16 and forms a first spline segment on the tube, thereby realizing the simultaneous extrusion of two-segment splines.

[0017] The angles between the inlet surface 11, the first die entry surface 12, the first forming surface 13, and the first outlet surface 14 and the center line of the first die core 1 are 28°-32°, 18°-20°, 0°, and 5°-7°, respectively. The angles between the second die entry surface 7, the second forming surface 6, and the second outlet surface 5 and the center line of the second die core 4 are 9°-11°, 0°, and 5°-7°, respectively. This ensures that the extrusion pressure of the equipment changes smoothly and the metal accumulation speed is stable during the extrusion feeding process of the tube.

[0018] The lengths of the inlet surface 11, the first mold entry surface 12, and the first forming surface 13 are 5.7mm-5.9mm, 3.1mm-3.3mm, and 2.4mm-2.6mm, respectively. The lengths of the second mold entry surface 7 and the second forming surface 6 are 9.55mm-9.95mm and 2.9mm-3.1mm, respectively. This can reduce the extrusion pressure of the equipment during the extrusion process and also reduce the difficulty of metal accumulation.

[0019] This invention can be used for forming involute splines of medium and small modules. The processed products can also be hollow shaft products. This invention can extrude two-stage external splines of hollow shafts, which can effectively reduce extrusion pressure and improve spline extrusion accuracy. It is suitable for pulse cold extrusion equipment and has a wide range of applications.

[0020] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A combined mold for extruding two-section splines, characterized in that: It includes a first mold core (1), a second mold core (4) and a positioning pin (2), and the first mold core (1) and the second mold core (4) are fixedly connected by the positioning pin (2); Multiple first internal spline tooth blocks (3) and second internal spline tooth blocks are fixedly arranged at intervals in the first mold core (1) and the second mold core (4), respectively. The tooth top of the first internal spline tooth block (3) is provided with an inlet surface (11), a first mold entry surface (12), a first forming surface (13) and a first outlet surface (14) in sequence. The tooth top of the second internal spline tooth block is provided with a second mold entry surface (7), a second forming surface (6) and a second outlet surface (5) in sequence. Multiple inlet surfaces (11), first mold entry surfaces (12), first molding surfaces (13) and first outlet surfaces (14) are evenly spaced around the center line of the first mold core (1) and respectively form an inlet surface region (18), a first mold entry surface region (17), a first molding surface region (16) and a first outlet surface region (15). Multiple second mold entry surfaces (7), second molding surfaces (6) and second outlet surfaces (5) are evenly spaced around the center line of the second mold core (4) and respectively form a second mold entry surface region (10), a second molding surface region (9) and a second outlet surface region (8).

2. The combined mold for extruding two-section splines according to claim 1, characterized in that: The angles between the inlet surface (11), the first mold entry surface (12), the first forming surface (13), and the first outlet surface (14) and the center line of the first mold core (1) are 28°-32°, 18°-20°, 0°, and 5°-7°, respectively.

3. A combined mold for extruding two-section splines according to claim 1, characterized in that: The angles between the second mold entry surface (7), the second forming surface (6), and the second exit surface (5) and the center line of the second mold core (4) are 9°-11°, 0°, and 5°-7°, respectively.

4. A combined mold for extruding two-section splines according to claim 1, characterized in that: The lengths of the inlet surface (11), the first mold entry surface (12), and the first forming surface (13) are 5.7mm-5.9mm, 3.1mm-3.3mm, and 2.4mm-2.6mm, respectively.

5. A combined mold for extruding two-section splines according to claim 1, characterized in that: The lengths of the second mold entry surface (7) and the second forming surface (6) are 9.55mm-9.95mm and 2.9mm-3.1mm, respectively.

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