JPH0252577B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a socket with a handle for a ball joint, that is, a shaft-like portion and two opposing shafts having an axis perpendicular to the axis of the shaft at one end or an intermediate portion of the shaft. This invention relates to cold forging a tie rod end housing having a concave portion in a continuous forming process using a transfer press as shown in FIG.

Cold forging of tie rod end housings (hereinafter referred to as "tie rods") is advantageous in that energy costs can be lower than hot forging. Also, our invention, which we filed earlier (Japanese Patent Application Laid-Open No. 1983
-139137), a so-called ball stud-shaped material with a spherical head upset at one end is prepared, a socket is formed on the spherical head, and the shaft is bent into the desired shape. Therefore, when the tie rod is cold formed, there is an advantage that the amount of burr generation can be suppressed and the material yield can be improved.

However, according to the conventional method, by forming a burr along the maximum contour of the forged tie rod,
In order to obtain the detailed shape of the tie rod, it was essential to form burrs.

By the way, when forming tie rods, if the shaft part bending process (Fig. 4 A, B) and the final forming process (Fig. 3 A, B) are to be carried out consecutively, Japanese Patent Application Laid-Open No. 55-139137 As in, the material was reversed between both processes. If you try to do this with a normal transfer unit, it is difficult to turn the material over and transport it, and if you force the material to be reversed between processes, the machine will often stop due to problems in transporting the material, resulting in a decrease in production efficiency. become the cause.

Therefore, when molding a tie rod, if each molding process is carried out consecutively using a transfer press, the material should be adjusted in the shaft bending process in the previous process to match the vertical orientation of the material in the final forming process, as shown in Figure 3. If an attempt is made to bend the material into a chevron shape, as shown in FIG. 5, the horizontal stability of the material will be poor, causing an uneven load to act on the material ball head 2b. Therefore, there is a problem that the material 1b moves in the material axis direction during forming, resulting in forging defects, and even if forged forcibly, the die life and forming accuracy deteriorate.

In addition, since the tie rod has an asymmetrical shape, the forming punch in the recessed part of the head receives thrust in a direction perpendicular to the main forming direction during forming, making it easy to break and making it difficult to form the recessed part deeply. The diameter of the recess could not be made close to the desired shape.

The object of the present invention is to provide a method for cold forging tie rods using a transfer press, which solves the above-mentioned conventional drawbacks.

The present invention will be described below with reference to drawings of embodiments.
Figures 1 and 6 to 11 show an automotive tie rod end housing (hereinafter referred to as a "tie rod").
This shows the forging process. The steps will be explained in order using these figures.

(Material cutting process) Fig. 1 A. First, a steel round bar with a circular cross section approximately equal to the diameter of the tie rod shaft portion 3d is cut, and the bar-shaped material 1 has the required mass.
Prepare a.

(Ball stud forming process) Fig. 1b In order to give the material 1a the mass distribution necessary to obtain the desired tie rod 4d, a spherical head 2b is mounted on one end of the bar-shaped material 1a by forging or a header, and the ball stud is formed. The material 1b is formed into a shape.

This step is carried out by a method known as a method for manufacturing ball studs, which are a part of ball joints for automobile suspension systems and steering systems.

(Shaft bending process) Figure 1 C, E and 6
Figures to Figures 9 First, the molding die portion of the transfer press used in this process will be explained with reference to Figure 6.
In the figure, 11 is an upper mold and 13 is a lower mold. 1
0 is a support means for horizontally supporting the ball stud-shaped material 1b within the die engraving portion of the lower mold 13. This support means 10 includes a lower mold movable portion 14 that can be raised and lowered with respect to a lower mold main body portion 17;
and a power transmission section 18 that moves the motor up and down.

The lower mold movable part 14 supports the material shaft part 3b at a predetermined height in the raised position, and is related to the power transmission part 18 so as to descend when a force exceeding a set value is applied to itself during the molding process. There is. The lowered position of the lower mold movable portion 14 is taken into consideration at the design stage so that when the material shaft portion 3b is bent by a desired amount, it abuts against a pressure plate (not shown) and stops.

It should be noted that a carved part having a substantially half-moon shape in cross section is formed on the upper surface of the lower mold movable part 14 to fit the outer periphery of the material.

The power transmission part 18 includes a tank part 20 that receives pressurized fluid such as compressed air from the outside and applies hydraulic pressure in the circuit, an elevating cylinder 23 that raises and lowers the lower movable part 14 via a piston rod 24, and an elevating cylinder. A relief valve 22 that opens when a pressure higher than a set value is generated in the tank 23, a check valve 21 that prevents oil from flowing back into the tank 20, and pipes 25, 26, 27, 28, 29 that connect these.
It is composed of.

In addition, a ball stud-shaped material 1 horizontally supported by a fulcrum protrusion 16 is provided in the die engraving portion of the lower die main body portion 17.
It is formed so as to protrude as much as possible to serve as a bending fulcrum for the shaft portion 3b, facing the lower surface of the shaft portion 3b near the spherical head portion 2b of the shaft portion 3b.

A spherical head 2 of a ball stud-shaped material 1b is provided with a locking protrusion 12 horizontally supported in the die engraving part of the upper die 11.
Mold 11 when bending the material facing the head of b.
It is formed to protrude in order to prevent the material 1b from moving in the material axial direction relative to the material 13. This locking protrusion 1
2 is formed at the tip of a punch 19 that is integrally fixed to the upper die 11.

Further, a knockout 15 is installed in the lower die 13 so as to be movable up and down on the same axis as the punch 19 and facing the punch 19. The upper surface of this knockout 15 supports the top of the bottom surface of the spherical head 2b of the material when horizontally supporting the material 1b, and also constitutes a part of the bottom surface of the lower mold engraving section.

Next, the formation of the ball stud-shaped material 1b using the above-mentioned molding die will be explained.

As shown in FIG. 6, the lower movable part 14 is in the raised position due to external pressure acting on the tank 20. That is, the oil in the tank 20 flows into the lifting cylinder 23 via the pipe 25, the check valve 21, and the pipes 26 and 27, and pushes up the lower movable part 14 via the piston rod 24. The shaft portion 3b of the ball stud-shaped material is fitted into the die cut portion of the movable portion 14 of the lower mold, and the ball stud-shaped material 1b is inserted into the lower mold 13 as shown in FIG. As a result, the ball stud-shaped material 1b is supported by the lower mold engraving part with its axis being horizontal.

Subsequently, when the upper mold 11 is lowered, as shown in FIG. 7, the horizontality of the material 1b is maintained by the lower mold movable part 14, so that the locking protrusion 12 is moved perpendicularly to the material axis without being displaced. It is struck against the top of the spherical head 2b. Almost at the same time, the upper half of the shaft portion 3b is covered by the mold engraving portion of the upper mold 11, and the shaft portion 3b is held between the lower mold movable portion 14 and the upper mold 11.

By gripping the shaft portion 3b with the mold in this manner, the ball stud-shaped material 1b is stabilized by suppressing unnecessary movement when the locking protrusion 12 subsequently enters the spherical head 2b. and retained. Therefore, as shown in FIG. 8, the spherical head 2b of the locking projection 12 can be seated perpendicularly to the material axis between its distal end surface and the upper end surface of the knockout 15.

That is, after the material shaft portion 3b is gripped by the mold, the lower mold movable portion 14 descends in synchronization with the lowering of the upper mold 11 while holding the material shaft portion 3b between it and the upper mold 11. do.

At this time, in the power transmission portion 18, the relief valve 22 detects the grasping of the material shaft portion 3b by the mold due to the pressure increase in the lifting cylinder 23, and opens, thereby allowing the piston rod 24 to descend. By opening the relief valve 22, the oil in the lifting cylinder is returned to the tank part 20 while providing some resistance to the downward pressure applied to the lower mold movable part 14 via the pipes 27, 28, 29 and the relief valve 22. .

When the upper mold 11 is further lowered, the shaft portion 3b of the material 1b is formed into a chevron-shaped bent portion 4c by the fulcrum projection 16 of the lower mold, as shown in FIG.

At this time, the shaft portion 3b side of the material is being gripped, and the spherical head 2b has also been driven into the locking protrusion 12 and has already been flattened to form a preliminary recess 5c. Loads are applied to the left and right in the material axis direction centering on the material 1b, and the material 1b is not subjected to any unbalanced load that would cause it to move in the material axis direction, and can be easily bent into a desired shape in an extremely stable state.

Therefore, the bending and forming of the shaft portion can be completed as shown in FIG. 9 without putting any force on the molds 11 and 13.

In the bending deformable material 1c having the preliminary concave portion 5c formed in this way, as the upper mold 11 rises, the lower mold movable part 14 is raised by the power transmission part 18, and the knockout 15 is activated. As a result, it is knocked out from the lower die 13 engraving.

The power transmission part 18 is configured such that the relief valve 22 closes due to the pressure drop in the lifting cylinder 23 as the upper die 11 rises, and the check valve 2 closes.
0 opens again, thereby lifting cylinder 23
The oil supplied to the piston rod 24 acts to raise the movable part of the lower mold.

(Final molding process) Figure 1 D, F and 10
FIG. 11 First, with reference to FIG. 10, the molding die portion of the transfer press used in this process will be explained. In the figure, 31 is an upper mold and 32 is a lower mold. Both molds have a carved part corresponding to the desired tie rod 1d divided into two parts. Note that since the material shaft portion 3c has been formed in the previous step, the shape of the die-carved portion covering the material shaft portion 3c, including the chevron-shaped bent portion 4c, is approximately the same as the outer shape of the material 1c. Therefore, in this example, the upper mold is punched 3
3, when it moves to the bottom dead center, it comes close to and faces the lower die 32, but the operation of the upper die is made double-acting so that the punch 33 is driven in after the upper die 31 descends, so that so-called closed forging is performed. It's okay.

A knockout 35 is attached to the lower mold 32 so as to be movable up and down. This knockout 35 is disposed in the lower die engraving part for forming the socket part 2d in the material head 2c, and its upper end surface abuts the bottom surface of the material head 2c to support the material 1c. , constitutes a die-cut surface that fits the bottom surface of the lower die-cut portion, particularly the socket opening 7d of the tie rod 1d.

In addition, the cylindrical peripheral wall portion 36 of the lower die 32 surrounding the tip portion of the knockout 35 is made larger than the upper portion in order to prevent the tip from shrinking and obtain a perfect desired shape by restricting the metal flow during molding of the socket portion 2d. The diameter is small.

Next, the forming of the bending deformable material 1c using the above-mentioned forming die part will be explained.

First, the bending deformable material 1c is conveyed by an ordinary transfer unit (not shown) from the die-cutting part of the shaft bending process to the die-cutting part of the main process without being reversed, and is shaped like a chevron as shown in FIG. It is inserted into the lower mold 32 with the shaft portion 3c including the bent portion 4c as a reference.

The seating of the material 1c in the lower die 32 is extremely good because the flattening of the spherical head and the bending of the shaft have been completed.

Subsequently, when the upper mold 31 descends, the punch 33 punches the preliminary recess 5 formed by the locking protrusion 12 in the previous step.
c, and further into the material head 2c as shown in FIG. At this time punch 3
3 is guided to the preliminary recess 5c and driven into the head 2c, no unbalanced load is applied to the punch 33, and the excess volume is pushed out into the space S formed at the lower end of the punch collar 34. The first recessed portion is formed without any burrs occurring in the mold cracked portion. Further, on the opposite side of the head 2c to the preliminary recess 5c, there is a second recess opposite to the preliminary recess 5c.
It is formed by the tip part of 5.

Furthermore, as the upper mold 31 descends, the material 1c is held in a closed manner by the mold, so that the shape accuracy of the socket portion 2d is improved due to the effect of the narrowed cylindrical peripheral wall portion 36 described above.

The tie rod 1d formed in this manner is knocked out from the lower die by the knockout 35, and then is completed by suitable machining as shown by the two-dot chain line in FIG.

As described above, according to the present invention, the space S is
By providing this, no burrs are generated, and the extra forming energy that would otherwise be required due to the generation of burrs is unnecessary, resulting in energy savings.

In addition, in the process of bending the shaft part, the ball stud-shaped material is kept horizontal by the horizontal support means, so the material can be molded into the desired shape correctly while maintaining the material in a stable state without putting any strain on the mold. The shaft of the ball stud-shaped material can be bent into a chevron shape in the shaft bending step in accordance with the vertical orientation of the material in the final forming process, and as a result,
There is no need to invert the material within the transfer unit. Furthermore, in the final molding process, the punch is guided into the preliminary recess formed in the previous process and driven into the spherical head, so that no uneven load is applied to the punch and the punch retains its shape well.

As described above, according to the present invention, the tie rod end housing can be efficiently forged using a transfer press.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the tie rod forming process by materials. Figure 2 is an explanatory diagram of the completed shape of the tie rod. FIG. 3 is an explanatory diagram showing the tie rod forming process desired in a transfer press using materials. FIG. 4 is an explanatory diagram of a preferred shaft portion bending process. FIG. 5 is an explanatory diagram of an undesirable shaft portion bending process. FIG. 6 to FIG. 9 represent an embodiment of the present invention, and are explanatory diagrams of a shaft portion bending and forming process. Figures 10 and 11
The figure represents an embodiment of the present invention and is an explanatory view of the socket part molding process. Explanation of symbols, 1b...Ball stud-shaped material,
1c...Bending deformable material, 1d...Tie rod, 2b...Spherical head, 2d...Socket part, 3
b...Shaft part, 5c...Preliminary recessed part, 10...Supporting means, 13...Lower mold, 14...Lower mold movable part, 16
...Fulcrum projection, 34...Punch collar, S...Space.

Claims (1)

[Claims] 1. In a method of cold forging a tie rod end housing using a transfer press, a ball stud-shaped material 1b having a spherical head 2b at one end is prepared, and the ball stud-shaped material 1b is
The ball stud-like material 1b has a support means 10 for horizontally supporting the material by a lower mold movable part 14, and protrudes as much as possible to serve as a bending fulcrum at an intermediate portion between the spherical head 2b and the shaft 3b of the horizontally supported ball stud-like material 1b. While horizontally supporting the ball stud-like material 1b by the lower die 13 having the fulcrum projection 16, the shaft portion 3 is attached to the spherical head 2b of the ball stud-like material 1b.
A bending deformable material 1c is formed by simultaneously performing the step of processing the recess 5c in a direction perpendicular to b to form a preliminary recess 5c of the first recess and the step of processing the surface portion of the intermediate portion into a chevron-shaped bent portion 4c. Then, the bent and deformed material 1c is moved to the next process mold in a transfer press without being reversed,
A space S is provided between the upper end of the socket portion 2d of the tie rod 1d to be molded and the lower end of the punch collar 34, and the portions close to the bottom of the preliminary recess 5c are pushed in the axial direction of the preliminary recess 5c so that they face each other. A method for cold forging a tie rod end housing using a transfer press, characterized in that a first recess and a second recess are processed.