JP2003048038A - Pipe rack forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate formation of rack teeth, to secure tooth precision easily, and also to increase bending strength of the rack teeth, in a pipe rack forming device. SOLUTION: The tip end face 31B of a tooth profile forming face 31A is designed to have a radius shape in a tooth profile die 20, in the pipe rack forming device 10.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pipe rack forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as a pipe rack forming device, as described in Japanese Patent Publication No. 3-5892, a flat surface portion of a pipe molded body is pressed by a tooth forming surface of a tooth profile of a tooth profile die, and the pipe molding is performed. There is a method in which a mandrel is pushed toward and away from the inner circumference of the body to raise the meat of the flat surface portion of the pipe molded body to mold rack teeth.

[0003]

In the prior art, since the tip end surface of the tooth forming surface of the tooth profile die is a flat surface, there are the following problems.

[0004] The flow of the meat of the pipe molded body that is raised on the outer periphery of the flat end surface of the tooth forming surface of the tooth profile die is poor, and the processing load increases. Therefore, it is difficult to form the rack teeth, and it is difficult to ensure the accuracy of the tooth profile of the rack teeth.

The bottom of the rack tooth forms a flat surface corresponding to the tip flat surface of the tooth forming surface of the tooth profile die, and an angle is generated at the root of the rack tooth to easily cause stress concentration, resulting in low bending strength of the rack tooth. .

An object of the present invention is to facilitate the formation of rack teeth in a pipe rack forming apparatus, ensure the accuracy of the tooth profile, and further improve the bending strength of the rack teeth.

[0007]

According to a first aspect of the present invention, the flat surface portion of the pipe molded body is pressed by the tooth forming surface of the tooth profile portion of the tooth profile die, and the mandrel is pushed forward and backward on the inner periphery of the pipe molded body. Then, in the pipe rack forming apparatus for forming rack teeth by raising the meat of the flat surface portion of the pipe formed body, the tip end surface of the tooth forming surface of the tooth profile die has an R shape.

According to a second aspect of the present invention, in addition to the first aspect of the invention, the tooth profile die is fixed to the tooth profile holder by a wedge block.

[0009]

According to the invention of claim 1, the following effects are obtained. The meat flow of the pipe molded body that is raised on the outer periphery of the tip R surface of the tooth forming surface of the tooth profile die becomes smooth.

The root of the rack tooth becomes an R surface corresponding to the tip R surface of the tooth forming surface of the tooth profile die, and the bending strength of the rack tooth is improved.

According to the invention of claim 2, there is the following action. By using the wedge block, the tooth mold can be easily and firmly fixed.

[0012]

1 is a side view showing a pipe rack forming apparatus, FIG. 2 is a front view showing a tooth mold and a holding mold, and FIG. 3 is a schematic view showing a plane forming state of a pipe formed body. 4 is a schematic view showing a tooth forming state of the pipe molded body, FIG. 5 is a front view showing a tooth profile holder assembly, FIG. 6 is a plan view of FIG. 5, and FIG.
6 is a sectional view taken along the line VII-VII of FIG. 6, FIG. 8 shows a tooth profile die, (A) is a plan view, (B) is a sectional view, and FIG. 9 is a front view showing the tooth profile of the tooth profile die. 10 indicates a wedge block,
(A) is a side view and (B) is a plan view.

The pipe rack forming apparatus 10 is shown in FIGS.
As shown in, a pipe molded body 1 in which a flat surface portion 2 is formed in advance on a part of the pipe material has a constant convex final tooth profile 3.
The rack teeth 4A of the pipe rack 4 are molded.

As shown in FIG. 1, the pipe rack forming apparatus 10 has a tie plate 13 fixed on an upper portion of a guide post 12 erected on a pedestal 11, and the tie plate 13 is pressed by a pipe such as a hydraulic servo cylinder or a screw press. The holding device 14 is installed, and the plunger 15 of the pipe pressure holding device 14 can be moved up and down by hydraulic pressure.
The saddle 16 provided in the guide is guided by the guide post 12. A tooth mold 20 is detachably installed on the lower surface of the plunger 15.

On the other hand, in the pipe rack forming apparatus 10, the anvil 17 is fixed directly below the plunger 15 in the pipe pressing and holding apparatus 14, and the holding die 4 is attached to the upper surface of the anvil 17.
0 is detachably installed.

As shown in FIGS. 2 and 5 to 7, the tooth profile die 20 (FIG. 8) is inserted into the recessed groove 21A provided in the tooth profile holder 21, and the support base disposed at the groove bottom of the recessed groove 21A. Board 2
2 has a slope (for example, 3 degrees) of wedge blocks 24, 24 (FIG. 10) on both sides which are also mounted adjacently on the support base plate 22 and are attracted to the tooth profile holder 21 by the bolts 23. The wedge surface 24A is wedge-bonded to the wedge surfaces 20A at both ends and fixed to the tooth profile holder 21. The wedge block 24 has a cylindrical surface 24B supported by arcuate surfaces 21B provided on both sides of the concave groove 21A of the tooth profile holder 21 in the longitudinal direction.

The tooth profile die 20 has a wedge surface 2 only on one end side.
0A and a cylindrical surface 20B is provided on the other end side.
B may be supported by the arcuate surface 21B of the tooth profile holder 21 (FIG. 8).

The tooth profile die 20 has a tooth profile portion 31 having a tooth forming profile surface 31 corresponding to the final tooth profile 3 of the rack teeth 4A of the pipe rack 4.

In the tooth profile die 20, as shown in FIG. 9, the front end surface 31 of the tooth forming profile surface 31A of the tooth profile portion 31.
B has an R shape. Tip R surface 31B is tooth forming surface 3
It forms an arc surface centered on the center line of 1A, and the tip R surface 3
The tangents of both ends of 1B are along a side surface 31C that is inclined at a constant angle (for example, 20 degrees) with respect to the center line of the tooth profile 31A.

As shown in FIG. 2, the holding die 40 has a holding portion 41 corresponding to the tooth forming surface 31A of the tooth-shaped portion 31 of the tooth-shaped die 20, and the outer periphery of the pipe molding 1 excluding the flat portion 2.
In the present embodiment, the arcuate outer periphery is supported.

The pipe pressing and holding device 14 includes the plunger 1
By moving up and down 5, the tooth profile portion 31 of the tooth profile die 20 is brought into contact with and separated from the pipe molded body 1 held by the holding portion 41 of the holding die 40, and the pipe molded body 1 is held between the tooth profile portion 31 and the holding portion 41.
Press and hold.

In the pipe rack forming apparatus 10, a mandrel pressing advancing / retreating device 50 composed of a hydraulic cylinder is installed on the side of the pipe pressing holding device 14 in the gantry 11, and a mandrel base 55 is attached to / detached from a plunger 54 of the mandrel pressing advancing / retreating device 50. Install freely. The mandrel base 55 is a small diameter to a large diameter that is sequentially pressed into the inner periphery of each pipe molded body 1 pressed and held between the toothed portion 31 of the toothed mold 20 and the holding portion 41 of the holding die 40 to be pushed back and forth. Multiple mandrels 5
1 to 53 (FIG. 4).

The procedure for forming the pipe rack 4 by the pipe rack forming apparatus 10 is as follows.

(1) A flat portion 2 is formed on a part of a pipe material to obtain a pipe molded body 1 (FIG. 3). In this pipe molded body 1, as shown in FIG. 3, a holding mold 61 is installed on the anvil 17 of the pipe rack molding apparatus 10, a pressing mold 62 is installed on the plunger 15, and the pressing mold 62 is pressed. Forming surface 62
The flat portion 2 can be molded with A. At this time, a cored bar may be inserted into the pipe molded body 1.

(2) In a state where the pipe molded body 1 is held by the holding portion 41 of the holding die 40, the flat surface portion 2 of the pipe molded body 1 of the tooth profile portion 31 of the tooth profile die 20 is held by the pipe pressing and holding device 14. The tooth forming surface 31A is pressed and crushed (FIG. 4).

(3) The mandrel pressing advancing / retreating device 50 reduces the diameter of the inner surface of the pipe molded body 1 pressed and held by the tooth profile portion 31 of the tooth profile die 20 and the holding portion 41 of the holding die 40 in the above (2). The large-diameter mandrels 51 to 53 are press-fitted in order and pushed forward and backward to push the meat of the flat surface portion 2 of the pipe molded body 1 into the mandrels 5 respectively.
1 to 53 are sequentially piled up and embedded in adjacent convex recesses of the tooth profile 31 to finally obtain the rack tooth 4A of the final tooth profile 3 (FIG. 4).

In the pipe rack forming apparatus 10, as shown in FIG. 4, the mandrel pushing / retracting operation with respect to the inner periphery of the pipe formed body 1 is performed by two pipes facing each other from both ends thereof. Mandrels 51 and 51 ', 52 and 5
Alternatively, 2 ', 53 and 53' may be press-fitted alternately.

Further, in the pipe rack molding apparatus 10, the tooth profile die 20 has a plurality of steps of tooth profile portions 31 to 33 (not shown), and the tooth profile forming surface 31 of the tooth profile portions 31 to 33 of each stage.
The height positions of A to 33A (not shown) may be different. Then, the flat surface portion 2 of the pipe molded body 1 is replaced with the tooth profile die 20.
Tooth mold forming surfaces 31A to 33A of the tooth profile portions 31 to 33 of the respective stages
When pressing with, the tooth profile portions 31 to 33 of the tooth profile die 20.
The tooth profile portion 3 that the tooth bottom height applied to the flat surface portion 2 decreases in sequence
1 to 33 are used in order, and mandrel 51 to 53 of the same diameter is pressed to the inner circumference of the pipe molded body 1 every time the tooth profile parts 31 to 33 of each step of the tooth profile die 20 press the flat surface part 2. You can repeat going back and forth. According to this, the crushing amount of the pipe molded body 1 by the tooth profile portions 31 to 33 of the respective steps of the tooth profile die 20 can be set to a small value from the beginning so as not to be excessively large so as to correspond to the root height of the final tooth profile. , It is not necessary to reduce the dimensions of the mandrels 51 to 53 press-fitted into the inner periphery of the pipe molded body 1 crushed by the tooth profile portions 31 to 33 of each step, and the mandrels 51 to 53 are not required.
The breakage of can be avoided. The small-diameter pipe rack 4 can also be easily molded.

According to this embodiment, there are the following effects. Tip R surface 3 of the tooth forming surface 31A of the tooth mold 20
The meat flow of the pipe molded body 1 raised on the outer periphery of 1B becomes smooth, and the rack teeth 4A can be easily formed and the accuracy of the tooth profile can be easily ensured.

The root of the rack tooth 4A becomes an R surface corresponding to the tip R surface 31B of the tooth forming surface 31A of the tooth profile die 20, and the connection from the root of the root of the rack tooth 4A to the tooth surface is round. It becomes smooth, stress concentration is less likely to occur, and the bending strength of the rack teeth 4A is improved.

By fixing the tooth profile die 20 to the tooth profile holder 21 by the wedge block 24, the tooth profile die 20
Can be fixed easily and firmly.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, and changes in design within the scope not departing from the gist of the present invention. Even so, it is included in the present invention.

[0033]

As described above, according to the present invention, in the pipe rack forming apparatus, it is possible to facilitate the formation of the rack teeth, ensure the accuracy of the tooth profile, and further improve the bending strength of the rack teeth. it can.

[Brief description of drawings]

FIG. 1 is a side view showing a pipe rack forming apparatus.

FIG. 2 is a front view showing a tooth profile mold and a holding mold.

FIG. 3 is a schematic diagram showing a flat surface molding state of a pipe molded body.

FIG. 4 is a schematic view showing a tooth forming state of a pipe molded body.

FIG. 5 is a front view showing a tooth profile holder assembly.

FIG. 6 is a plan view of FIG.

7 is a sectional view taken along the line VII-VII of FIG.

FIG. 8 shows a tooth mold, (A) is a plan view,
(B) is a sectional view.

FIG. 9 is a front view showing a tooth profile of a tooth profile mold.

FIG. 10 shows a wedge block, (A) is a side view, and (B) is a plan view.

[Explanation of symbols]

1 Pipe molding 2 flat surface 4 pipe rack 4A rack teeth 10 Pipe rack forming equipment 20 tooth mold 21 Tooth profile holder 24 wedge block 31 Tooth profile 31A Tooth forming surface 31B tip R surface

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshihisa Mikami             1-14 Fujiwara-cho, Gyoda-shi, Saitama 1 Stock             Company Showa Saitama Head Office Factory F-term (reference) 4E087 HA06

Claims (2)

[Claims] 1. A flat portion of a pipe molded body is pressed by a tooth forming surface of a tooth profile of a tooth profile die, and a mandrel is pushed and retracted to the inner periphery of the pipe molded body to remove the meat of the flat surface portion of the pipe molded body. A pipe rack forming apparatus for forming a rack tooth by raising it, characterized in that a tip surface of a tooth forming surface of a tooth profile die has an R shape. 2. The pipe rack molding apparatus according to claim 1, wherein the tooth profile die is fixed to the tooth profile holder by a wedge block.