JPH07100757A - Burnishing and burnishing tool - Google Patents

Abstract

PURPOSE:To uniformly grind the inner surface of a thin and long metal tube and dissolve the noise nuisance by using a mandrel which can be deformed or shifted, following the shape of the metal tube. CONSTITUTION:The covering body 7 of the mandrel 1 of a burnishing tool which is inserted into a thin metal tube to be worked is formed from a member using a deformable elastic body such as synthetic resin and rubber. When burnishing work is applied on the inner surface of the thin metal tube by the burnishing tool, the covering body 7 of the mandrel 1 as elastic body is deformed, following the shape of the inner surface of the metal tube through a roller, and at the same time, a prescribed burnishing pressing pressure acts, and burnishing work can be applied. For example, the mandrel 1 is formed into a double structure, and the covering body 7 is compounded with the mandrel 1. The covering body 7 is made of nylon through molding or cutting and formed integrally with the mandrel 1 firmly by the means such as fusion adhesion, adhesion, and screw fixing, and fixed on a shaft 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burnishing process for an inner surface of a metal pipe, which is performed by rolling a roller or a ball.
The present invention relates to a burnishing method and a burnishing tool for improving the surface roughness and strength of the inner surface of a metal tube. More specifically, the metal tube is thin and has variations in inner diameter and shape,
The present invention relates to a burnishing method and a burnishing tool which follow burnishing processing even if there is distortion.

[0002]

2. Description of the Related Art Conventional internal burnishing processes include hydraulic and pneumatic cylinders, synthetic resin extrusion molding cylinders, and other metal pipes with high rigidity and dimensional accuracy.
Alternatively, it has been put to practical use as a processing method for a product that requires mirror finishing of the inner surface of a metal member. That is, it has been usual to perform a high-precision boring process on a solid steel material or a thick-walled steel pipe and perform a burnishing process with a burnishing amount of 0.02 to 0.07 mm.

On the other hand, a metal tube having a small wall thickness and poor precision could not be burnished. That is, stainless steel sanitary tubes used in the food industry and the like are stipulated in JIS G3447 to be No. 400 polished in order to make the inner surface smooth. For example, outer diameter: 38.1 mm, wall thickness: 1.2 mm
The solution-heat-treated thin-walled stainless steel sanitary tube having a length of 4000 mm 2 could not have its inner surface smoothed by any method other than No. 400 polishing.

[0004]

The following is an example of what is referred to as a thin-walled metal tube in the roller burnishing process. That is, in the product name "Superoll" of Sugino Machine Co., Ltd.'s roller burnishing tool, the metal tube requires a wall thickness of at least 20% of the inner diameter in order to withstand the pressure of the burnishing process. It is said that a thinner metal tube may not provide a sufficient burnishing effect.

In the above-mentioned thin metal tube, during the burnishing process on the inner surface of the metal tube, the location of the roller is
Since the snake bulges outward like an swallowing egg (this bulge becomes more apparent as the metal tube is thinner) and escapes, the pressing force of the roller does not sufficiently act on the thin metal tube, so There is a problem that the unevenness on the inner surface of the metal tube is not sufficiently crushed, that is, it is not smooth.

Furthermore, since the burnishing tool cannot follow the variation in the inner diameter dimension and the distortion such as the flatness which are remarkable in the thin-walled metal pipe, there are portions where the rollers do not contact, that is, portions where the burnishing cannot be performed. It was

The problem to be solved by the present invention is that sufficient burnishing can be performed even with a thin metal tube as described above.
The purpose is to allow the inner surface of the metal tube to have a smooth finish.

[0008]

In order to achieve the above object, in the method for processing the inner surface of a metal tube of the present invention, a mandrel of a burnishing tool to be inserted into a thin-walled metal tube to be processed is made of synthetic resin. The problem is solved by using a member that uses a deformable elastic body such as rubber or rubber.

Alternatively, the problem can be solved by interposing an elastic body at the joint portion of the mandrel or by having a function of swinging in the diameter direction and displacement function in the axial direction by hydraulic pressure.

[0010]

[Operation and configuration] When burnishing the inner surface of a thin metal tube with the burnishing tool configured as described above, the cover of the mandrel, which is an elastic body, follows the shape of the inner surface of the metal tube via the roller. At the same time as the deformation, the burnishing process can be performed by acting so as to exert a predetermined burnishing pressing force.

The mandrel cover described above can be used from relatively hard ones such as polyamide and polycarbonate to low hardness ones such as polyurethane and synthetic rubber, but the ones with low hardness are thinner metal tubes. It is suitable for burnishing. As an example of hardness, Rockwell R.I. From 100-180 engineering plastics, 18-125 nylon, polyurethane, etc. can be applied.

Further, the mandrel joint with the elastic member interposed works to follow the metal tube even if the metal tube is slightly bent.

The present invention will be described in detail below with reference to examples, but it goes without saying that the present invention is not limited to these examples. Further, in this embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a vertical cross-sectional side view of a main part of a conventionally known burnishing tool. On the outer side of the mandrel 1, a plurality of rollers 3 which are loosely fitted and sandwiched by a tubular frame 2 are arranged at predetermined intervals. The frame 2 is housed in a case 4 provided in the axial direction of the mandrel 1,
It is connected to the shank 5 together with the mandrel 1. Case 4, bearing, spring, adjustment screw, stop screw,
As a result, the taper of the mandrel 1 is used to adjust the diameter of the roller 3 to the outside and expand the diameter.

[0015]

[Embodiment 1] Embodiment 1 is shown in FIG. 2 and basically the same as FIG. The mandrel 1 of FIG. 1 has a double structure, and the mandrel 1 is combined with a cover 7. The cover 7 is
Made of nylon (polyamide) by molding or cutting, and firmly integrated with the mandrel 1 by means of fusion, adhesion, screwing, or a combination thereof.
It is fixed to the shaft 6.

[0016]

Embodiment 2 Embodiment 2 is shown in FIG. 3. In this embodiment, the mandrel 1 has a shaft 6 and a displacement function capable of expanding and contracting or swinging with respect to the frame 2, or both. . That is, the mandrel is not fixed to the shaft 6, but is loosely connected by the spline 8 provided on the shaft 6.

An elastic body (synthetic rubber) 9 is provided in the inner cavity of the mandrel 1, and the pressure from the shaft 6 is transferred through the elastic body 9.
Transmission is made from the tip plate 10 of the shaft 6 to the mandrel 1.

[0018]

Third Embodiment A third embodiment is shown in FIG. 4. In this embodiment, the elastic body of the second embodiment is used as a hydraulic bag 11, and a pump or a cylinder (not shown) is provided by a pipe 12 penetrating the shaft 6. The liquid pressure bag 11 is filled with the liquid under pressure to form an elastic body. This liquid is oil or water or an additive thereof added thereto.

Although the mandrel 1 is described as a conventional one in FIGS. 3 and 4, the mandrel 1 may be combined with the elastic cover 7 as in the first embodiment.

When performing roller burnishing,
Fine dust is generated when crushed by a roller, which adversely affects the finished surface. Therefore, it is preferable that a large amount of highly fluid processing oil, cleaning oil, or the like be poured on the inner surface for the treatment.

In this processing method, it is not preferable that the inner surface of the material to be processed has deep scratches, grooves, welding marks, etc., which are not crushed by the roller burnishing processing, and therefore the pipe is preliminarily cut, ground, drawn or the like. It is advisable to use a product whose inner surface is evenly finished.

Further, in the above-described embodiment, the mode in which the burnishing tool is pressed into the metal pipe for processing has been described.
For long metal pipes, it is better to work by pulling the tool.

Furthermore, although an example of processing a thin stainless sanitary pipe has been described above, the present invention is not limited to this, and the material to be processed and the processing form are not limited to the pipe. Also used for dairy farming and food industry stainless steel.
Needless to say, the present invention is not limited to sanitary tubes, and can be freely applied to pure water, chemicals, fibers, powders, gases, and the like.

[0024]

As described in detail above, according to the present invention,
Various effects as listed below can be obtained.

(1) Conventionally, as a sanitary pipe, JIS
No. 400 polishing is specified in G3447. In the polishing, usually, three steps are performed, that is, first, the 80th abrasive grain, then the buff with the 150th abrasive grain, or the cylindrical sandpaper finish, the 400th abrasive grain was applied. The buffs are fixed to the ends of long shafts, respectively, and they are rotated at high speed to grind from the end of the metal tube in sequence, but of course, the abrasive grains attached to the buffs fall off. Therefore, it is difficult to evenly polish the inner surface of a thin and long metal pipe, and there were problems such as dust pollution due to fine dust and noise pollution such as metal noise when hitting a metal pipe at high speed. Will be resolved.

(2) Burnishing can be performed on a thin metal tube (38.1 × 1.2 mm) having a wall thickness of 3.3% with respect to the inner diameter.

(3) Conventionally, in order to perform roller burnishing, it was necessary to cut the inner surface of the metal pipe before processing, but this is not always necessary in the present invention.

(4) Even if the metal pipe before processing is slightly deformed or slightly bent, burnishing can be performed following this. That is, it is suitable for polishing the inner surface of a metal pipe such as a pipe that does not require dimensional accuracy.

(5) Not only the inner surface of the thin-walled metal tube is crushed and smoothed, but also the corrosion resistance and wear resistance are improved, which makes it more suitable as a sanitary tube.

(6) Fatigue strength is improved by surface hardening and residual compressive stress as compared with No. 400 polishing.

(7) If the product of the present invention is further electropolished, the time required for expensive electropolishing is greatly shortened, and the finish of electropolishing becomes inexpensive.

(8) The mandrel cover is inexpensive and easy to replace.

(9) Since the mandrel is made of an elastic material, the wear of the roller is small and the life is long.

[Brief description of drawings]

FIG. 1 is a side view showing a vertical section of a main part of a conventional roller burnishing tool.

FIG. 2 is a side view showing a part of a main part of the burnishing tool according to the first embodiment.

FIG. 3 is a side view showing a part of the main portion of the second embodiment in a vertical section.

FIG. 4 is a side view showing a part of a main portion of the third embodiment in a vertical section.

[Explanation of symbols]

 1 Mandrel 2 Frame 3 Roller 4 Case 5 Shank 6 Axis 7 Mandrel cover 8 Spline 9 Elastic body 10 Tip plate 11 Hydraulic bag 12 Tube

Claims (5)

[Claims] 1. A burnishing method using a mandrel which can be deformed or displaced in accordance with the shape of a metal tube in burnishing with a roller. 2. The burnishing tool according to claim 1, wherein at least a part of the mandrel supporting the roller is an elastic body. 3. The burnishing tool according to claim 1, wherein a cover is provided on the mandrel supporting the roller, and the cover is made of an elastic body such as synthetic resin or synthetic rubber. 4. The elastic body comprises Rockwell R 18 to
The burnishing tool according to claim 2, having a hardness of 125 or 100 to 180. 5. The burnishing tool according to claim 1, wherein the mandrel is provided with a displacement function such as swinging in a diametrical direction and / or expansion / contraction in an axial direction by a rubber member or by hydraulic pressure.