JPS5947018A - Manufacture of metallic pipe - Google Patents

Abstract

PURPOSE:To obtain a thin-walled and lightweight metallic pipe, by forming one end of the short-sized metallic pipe into a thick-walled and expanded radius part and forming a locking flange part at the peripheral edge of the expanded part, and drawing the remaining part in the axial direction. CONSTITUTION:A metallic pipe 8 is pressed into the 1st die hole 6 of the 1st die 7 having an expanded radius part 5 at its upper opening surface, by a punch 9 in a cold state. The upper end part of a pipe 8a is formed into an expanded radius part and a locking flange part 10 projecting outward from the peripheral edge of the expanded part is formed, and the lower part of the pipe is drawn into a small diametral one along the die hole 6. Next, the pipe 8a is pressed in a cold state into the 2nd die, thereby the inner peripheral surface of it is formed into the thin-walled shape by expanding it radially and the pipe is simultaneously formed into the prescribed length by stretching it in the axial direction. In this case, the pipe part excluding the expanded part is surely drawn, because the lockiing flange part 10 is locked at the upper surface of the die while the drawing is performed. Next, the inner peripheral surface is formed into the specular surface by performing the drawing with the 3rd die. The flange part 10 is removed at the final finishing stage after forming, and a machining such as threading is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of manufacturing a metal pipe used, for example, in a hydraulic cylinder for power steering of a motor vehicle.

Conventionally, the manufacturing method for metal pipes like the example above was based on the required length. A long metal pipe with an enlarged diameter and a rectangular metal used as a connection part with other parts] (While it is provided by welding to the pipe, it is built in the inner Vi surface so that it can slide freely). Its inner circumferential surface was formed with a precise finish.

However, in this manufacturing method, the entire length of the metal pipe becomes as thick as the enlarged diameter portion, which requires a thick wall for strength reasons, and the weight of all Type 71 pipes increases.

Therefore, it is possible to use thin-walled metal pipes, but in this case, the strength and strength are likely to decrease due to welding with thin-walled parts, and in any case, since they are manufactured by welding, there is a possibility of thermal distortion or poor assembly. Is it a problem that it is easy to emit grape 58? had.

In addition, the inner circumferential surface of the metal pipe has a precise finish -1, = 1ilr
In order to form the metal pipe into a metal pipe, polishing work such as forming is required, and the number of manufacturing steps increases to obtain a precise finish.
fc is complicated, requires forming processing, etc., and is forced to increase costs.

Therefore, this invention is a burden f11(/?-
The present invention provides a method for forming a metal pipe without causing any damage or requiring forming processing or the like.

According to this invention, gold of short rice material 1. ..., (using a pipe, it can be drawn and formed into a lightweight gold R2i+ pipe of a predetermined length, and it can also be formed into a J?-vc molding type that corresponds to the pipe thickness of each part required for the molding grade). can.

That is, use a short metal pipe to cut one end.7. By forming the enlarged diameter part of the pipe and forming the entire locking flange around the periphery of the enlarged diameter part, this locking flange becomes the locking part necessary for the next process of thin-walled forming, and the remaining pipe is removed. part'f
r: If: i+ It is possible to apply a pattern or polishing process to extend in the direction of the gland. As a result, the formed tLlξ pipe is a thin-walled metal pipe having a predetermined length, and the overall weight can be reliably reduced. Therefore, it is possible to reduce not only the cost of materials but also the weight of the vehicle body, which is extremely beneficial.

In addition, as a final step, the inner circumferential surface of the bent pipe can be formed into a mirror finish by performing a drawing process with a small degree of processing on the inward facing surface of the pipe. 1-ililke(! can be done.

For this reason, metal pipes such as hydraulic cylinders can not only be formed by a series of drawing processes using dies and punches, but also thick-walled enlarged diameter sections that require thick walls can be formed, and other thin-walled It is possible to manufacture a metal pipe by forming a thin wall for the desired remaining pipe portion, and by using a manufacturing means that corresponds to each portion having a different wall thickness.

An embodiment of the present invention having such feature 1 will be described in detail below with reference to the drawings.

Fig. 1 shows a hydrostatic power steering system for an automobile, which includes a steering device 2 with all control valves built into the steering wheel 1, an oil sump 3 equipped with a pump for driving the steering gear 1, and wheels. A hydraulic cylinder 4 for operation is connected to the piping and formed into a wall.

Next, a method for manufacturing the metal pipe used in the above-mentioned hydraulic cylinder 4 will be explained.

FIG. 2 shows the first drawing process, "1 end t71] D
A first mold hole 6 having five enlarged diameter portions in i7n.
A metal pipe 8 as a short material is coldly press-fitted into the first mold hole 6 with a first punch 9, and a first drawing is performed. As a result, the upper end of the metal bending ring 8a is enlarged to the enlarged diameter 71; is molded, and the lower part is mostly narrowed to a small diameter in the first mold hole f3.

In addition to the first drawing process of Kamazeho, the next process is taken into account, and 9 trap drawing processes are performed. That is, a locking point 10, which will be described later as a thin-walled forming means, is formed at the same time as the enlarged diameter portion.

The above-mentioned locking flange 10 is molded with the entire ij'11 edge of the enlarged diameter part protruding outward, and when molded, the circumference 11 stepped part 11Vc formed on the first punch 9, Accordingly, the upper end of the metal pipe 8a is bent outward from the upper surface of the first mold hole 6. 1b ζ 1j minced 9 is v
; Corresponding to the enlarged diameter portion of the first dynu 7, it is formed in the shape of a '/ζ badge.

In addition, 12 is a lower pressure member which controls the variation in the elongation and wall thickness of the nozzle during molding.

Then, as shown in FIG. 3, the second die 14 having the second mold hole 13 is press-fitted with the second punch 15 after the first drawing step 9 and the metal pipe 8ak is coldly pressed into the second die 14 to form the second pattern. will be carried out. At this time, the second punch 15 is inserted into the inner hole of the pipe.
In order to pressurize the inner peripheral surface of the pipe through E h'ti, the inner peripheral surface of the metal pipe 8b is formed to have an enlarged diameter and a thin wall, and the pipe is stretched and formed to a predetermined length in the axial direction.

The pipe portion formed in this second drawing step is formed with the locking flange 10 locked on the upper surface of the second dynu 14, so that only the pipe portion other than the enlarged diameter portion can be reliably formed. It can be drawn.

Next, as shown in FIG. 4, the metal pipe 8b that has been subjected to the second drawing process is placed in the eighth die 17 provided in the third mold hole 16'.
? The third punch 18, which has a slightly larger diameter than the second punch 15, is used to press fit and perform the eighth drawing. At this time,
Since the 9J3 punch 18 is inserted into the pipe while applying light pressure to the inner circumferential surface of the pipe, only the surface m1 of the inner circumferential surface of the pipe is uniformly pressurized and mirror-finished. In the process, only a predetermined portion is drawn with the locking flange 10 being weighed against the third die 17.

In this way, a predetermined gold 1:1 spipe 8C is formed through a series of first to eighth drawing processes.
As shown in Fig. 5, in d, the locking flange is removed as a final finishing step, and a screw 1 is installed on the outer circumferential surface of the enlarged diameter part at the upper end of j.
9-piece machining process is applied.

The above-mentioned metal pipe is made of a material such as steel or aluminum alloy that is suitable for +iqi+ such as hydraulic cylinders, and the material thickness and basic vU length formula of the metal pipe are determined by the formation of the enlarged diameter part necessary for strength, The thickness is set to be the same as the thickness of the mold, and the length is set to be 4 times longer than the length of the pipe to be stretched after molding.

In the above-mentioned embodiment, a hydraulic cylinder for a power steering is shown as an example, but the cylinder is not limited to this, and other circular iVJ shapes having different wall thicknesses can also be formed.

[Brief explanation of the drawing]

The drawing shows one embodiment of this FJ4, and Figure 1 shows an automatic i
1f A perspective view showing the entire power steering system M used in K. Figure 2 shows the manufacturing method of the metal pipe used in the power steering hydraulic cylinder? FIG. 3 is a vertical cross-sectional view of the fc first patterning step. FIG. 3 is a longitudinal sectional view showing the second drawing process. Is Figure 4 the 8th drawing process? FIG. Figure 5 shows the state of a metal pipe that has been machined after all the drawing processes have been completed. FIG. 5... Enlarged diameter part 6, 18.16... Mold hole 7.14.17... Dice 8 + 8 a, 8 b, 8 c,... Metal pipe 9.15.18... Punch 10 ...Latching flange

Claims (1)

[Claims] 1. A metal pipe is press-fitted into the mold hole of a die having an enlarged diameter hole (1iii) at one end, and one end of the pipe is formed to an enlarged diameter of 4i1S, and the peripheral edge of the enlarged diameter part is
Pressure is applied so as to force it outward from the mold hole of the die, and the locking part is formed 17 (S'k I), and with the retaining part and the part locked in the next process, other pipe parts'f are formed. ：The entire length of the pipe is drawn and formed into a thin wall, and then the inside of the pipe is
A method for producing a metal pipe, characterized in that the inner circumference of the pipe is formed into a mirror surface by subjecting the td surface to a drawing process with a small degree of processing.