JPH08330100A - Inner duct surface working method - Google Patents

Abstract

PURPOSE: To lessen a force required for drawing out a broach by preventing the clogging of a broach tooth and the clogging of the broach in a duct. CONSTITUTION: Rectangular parallelepiped protrusions 2, integral protrusions 9, or cylindrical protrusions 10 are provided on the broach rake faces 3 of a broach tooth 1 so that cut chips 11 hit these protrusions. The cut chips 8 are bent and cut by the force of the advancing broach tooth 1 or the force of an advancing work to be cut. Wedge-shaped protrusions 13 are provided on the broach rake faces 3 so that cracks are produced in parallel with an advancing direction of the cut chips 11. Protrusions with round edges 14 are provided on the broach rake faces 3 so that the bending radii of the cut chips 11 are lessened. A broach shaft is formed into hollow, and using this space as a main path 15 a jet path 16 is provided toward the broach rake faces 3 from the main path 15 so that gas or liquid is jetted to collide with the broach rake faces 3 so as to finely chip the cut chips 11 soon after the formation thereof by this jetting force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method by broaching a beam duct which is a vacuum container of a charged particle accelerator.

[0002]

2. Description of the Related Art In a charged particle accelerator, in order to accelerate charged particles with high energy, it is necessary to prevent scattering due to collision between charged particles and residual gas and to prevent loss of charged particles.
In order to prevent this loss, the environment in which charged particles are accelerated must be in ultrahigh vacuum. In order to realize this ultra-high vacuum environment, a vacuum container such as a duct is used. In order to reduce the pressure and realize high vacuum or ultra-high vacuum, it is the most important issue to reduce the gas emission from the vacuum container and the like, in addition to increasing the exhaust speed of the vacuum pump. There are several surface treatment methods for reducing gas emission from the inner surface of the vacuum container. A vacuum container of a charged particle accelerator called a beam duct is usually made of aluminum alloy, stainless steel, copper or the like. The so-called thermal desorption, in which gas molecules adsorbed on the surface are desorbed by thermal energy, is dominant in the gas release from the vacuum container. However, in the charged particle accelerator, since high-energy particles exist inside the vacuum container, desorption of gas due to factors other than the usual thermal desorption greatly affects the pressure. For example, in an electron storage ring, electrons or positrons whose trajectories are changed by a deflection magnetic field or the like generate electromagnetic waves called synchrotron radiation due to bremsstrahlung. This radiated light irradiates the inner wall of the beam duct, and causes gas emission from the inner surface of the beam duct called photostimulation desorption. With regard to photostimulation desorption, for example, reference to Vacuum, volume 33, number 7 (1983), pages 397 to 406 (Vacuum, volume 33, number 7 (1983) page 397).
to 406). Outgassing caused by photostimulated desorption increases the pressure inside the beam duct. This results in scattering and decay of stored electrons. In order to suppress the release of these gases as low as possible, various surface treatments have been performed for the purpose of cleaning the inner surface of the inner wall of the beam duct and removing the compounds and contaminants that cause the release of gases. For example, chemical treatments such as pickling and alkali etching are the most common methods. Examples of the chemical treatment include literature vacuum, volume 38, number 8-10 (1988), pages 933 to 936 (Va
cuum, volume38, number8−10 (1988) page 933 to 93
6). In addition to chemical treatment, the inner surface of the vacuum container is bombarded by the ions generated by the discharge,
Discharge cleaning to remove adsorbates on the surface, pre-baking processing to evaporate and remove surface compounds by heating at high temperature in a vacuum furnace, and to release gas contained in the material to the outside by diffusion is there.

[0003]

Of the above-mentioned conventional techniques,
The purpose of the inner surface of the duct by broaching is to remove the gas emission source surface layer containing impurities on the surface of the material due to the high temperature processing during material preparation and the surface contamination layer due to the lubricant used during duct molding from the material. Especially. FIG. 2 shows a state of broaching for cutting the inner surface of the pipe. As shown in FIG. 2, a broach 7 in which a plurality of broaching blades 1 having the same cross-sectional shape as the inner cross section of the work 6 and having a cutting portion in the circumferential direction are arranged in the longitudinal direction moves inside the work 6. The inner surface is thereby cut. However, the size and shape of the cutting chips generated during processing are not constant, and when large cutting chips are generated, in the space formed by the adjacent broach blade 1 shown in FIG. 2 and the inner surface of the workpiece 6. The substantial space occupied by the cutting waste in a certain chip storage 8 becomes large, which causes clogging of the broach blade and clogging of the broach in the pipe, which causes an increase in the broach drawing force. Therefore, there have been problems such as poor workability of long pipes, early consumption of broach blades, increase in energy consumption such as electric power required for pulling out broaches, and increase in production cost due to equipment enhancement. In addition, if large chips are dragged on the inner surface of the duct,
The inner surface of the duct was scratched, and the surface condition of the cut finished surface was significantly deteriorated.

An object of the present invention is to improve the productivity of broaching of ducts, to obtain a high-performance beam duct for charged particle accelerators, which corresponds to a long duct and has a good cutting surface treatment condition at a low cost.

[0005]

The above problems can be solved by providing a protrusion on the rake face of the broach blade, or by providing a wedge-shaped protrusion or a rounded protrusion on the broach blade rake face. Further, it can be solved by jetting and colliding gas or fluid with the rake face of the broach blade.

[0006]

According to the present invention, when performing broaching on the inner surface of the duct, it is possible to reduce the cutting waste generated by cutting. Therefore, a large amount of cutting chips can be accumulated in the chip storage, which is a space formed by the broach blade and the inner surface of the duct. Also, since the volume occupied by the cutting waste in the chip storage can be reduced, clogging of the broach blade and clogging of the brooch in the duct are prevented, and the pullout force of the broach is reduced, reducing wear of the broach blade, In addition, energy such as electric power used in processing can be saved. Further, since large cutting waste is not dragged by the broach, scratches on the cutting surface can be reduced and a high quality cutting surface can be obtained.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 2 shows a state of broaching for cutting the inner surface of the pipe. As shown in FIG. 2, a broach 7 having a plurality of broach blades 1 having the same cross-sectional shape as the inner cross-section of the work 6 and having a cutting portion in the circumferential direction is moved inside the work 6. The inner surface is cut by. Next, examples of broaching blades used for the duct inner surface cutting treatment of the present invention are shown in cross-sectional views in FIGS. 1, 3 and 4. FIG. 1 is a view in which a plurality of rectangular parallelepiped projections 2 are arranged on a broach blade rake face 3 for scooping up cutting waste of a broach blade 1 used for cutting an inner surface of a duct having a rectangular cross section. Further, FIG. 3 is a diagram when a plurality of these rectangular parallelepiped projections 2 are put together on the broach blade rake face 3 as an integrated rectangular parallelepiped projection 9. FIG. 4 shows an embodiment in which a cylindrical projection 10 is provided on the broach rake face 3 instead of the rectangular parallelepiped projection 2 shown in FIG.

Next, referring to FIG. 4, the broach blade rake face 3
The present invention will be described with reference to an example in which the rectangular parallelepiped projection 2 is provided. In broaching, cutting is performed by moving either or both of the broach blade 1 and the work piece 6 in the broach blade moving direction 5 and the work piece moving direction 12, respectively. Cutting scraps generated by cutting 11
Hits the rectangular parallelepiped protrusion 2 along the broach blade rake face 3. After that, the broach blade rake face 3 that is moving relative to the cutting wastes 11 bends and cuts in the direction of the broach moving direction 5. Since the cutting chips are cut immediately after the generation, small cutting chips can be obtained. In this embodiment, only rectangular parallelepiped projections and cylindrical projections are taken up, but any shape can be used as long as it is on the broach rake face and suppresses the progress of cutting chips generated along the broach rake face. good.

FIG. 5 is a view in which a wedge-shaped projection 13 is provided on the broaching blade rake face 3. The sharp-angled portion of the wedge-shaped projection 13 is arranged toward the cutting surface, and therefore the cutting waste 11
Can be divided in parallel with the traveling direction of the cutting waste 11. Therefore, although the cutting waste 11 continuously extends, since the cross-sectional area is small, the cutting waste can be bent due to a collision with another cutting waste, and can be further cut into pieces.

FIG. 7 shows an embodiment in which the integral type rectangular parallelepiped projection 9 shown in FIG. 3 is provided with a smooth rounded rounded projection 14. The radiused protrusions 14 smoothly rounded from the broach rake face 3 reduce the radius of curvature of the cutting dust generated along the broach rake face 3 as compared with the cutting dust without the rounded protrusions 14. be able to. Therefore, if you cut the same amount,
It is possible to reduce the ratio of the cutting waste generated by the cutting with the broach blade provided with the rounded protrusions 14 in the chip storage 8 in the space formed by the adjacent broach blade 1 and the inner surface of the workpiece as shown in FIG. It is possible to increase the amount of cutting chips that can be accumulated in the inside 8. A plurality of the rounded protrusions 14 may be arranged on the broach rake face 3 as small protrusions as shown in FIG.

Next, the present invention will be described in which gas or fluid is jetted to the rake face of the broach blade to shred the cutting chips 11 immediately after they are produced. FIG. 8 is a cross-sectional view of the broach 7 showing an embodiment for injecting gas or liquid onto the broach blade rake face 3. The hollow space of the broach shaft serves as the main flow path 18, and the broach shaft 4 extends from the main flow path 18 toward the broach blade rake face 3.
One or more ejection passages 19 penetrating through are provided in the circumferential direction of the broach shaft 4. Plug 1 from one end of brooch 7
Gas or fluid is supplied to the main flow path 15 by the hose 18 connected by 7, and jetted and collided from the jet flow path 16 to the broach rake face 3. By using the jetting force of the gas or fluid at this time, it is possible to shred the cutting chips generated by cutting. As a result, since the cutting waste can freely move in the chip storage, it is possible to prevent the cutting waste from being galled by the broach blade. Furthermore, since the substantial space occupied by the cutting waste in the chip storage is reduced and a large amount of cutting waste can be accumulated, broaching into a long duct becomes possible. Further, if an inert gas is used as the gas to be supplied, it is possible to prevent the cutting surface of the workpiece from being oxidized. Furthermore, by using lubricating oil for the fluid,
Lubricating oil can also be used as the jet fluid. FIG. 9 shows an example of a vacuum duct in which flanges 20 are welded to both ends of a duct 19 having a rectangular cross section, which has been cut by the above-mentioned broaching process. In addition, if the beam duct of the charged particle accelerator is subjected to the broaching surface treatment of the present invention, the surface contamination layer and the alteration layer, which are gas emission sources, can be removed because the inner surface has undergone cutting, and thermal desorption and It is possible to reduce gas emission such as photostimulation desorption caused by irradiation of synchrotron radiation in the electron storage ring, and suppress reduction of charged particles. Further, it is possible to obtain a beam duct for a high-performance accelerator with a high-quality processed surface.

[0012]

According to the present invention, when carrying out the broaching of the inner surface of the duct, it is possible to reduce the cutting waste generated by cutting. Therefore, compared to the case where large chips are generated, a larger amount of chips can be stored in the chip storage, which is the space formed by the broach blade and the inner surface of the duct, enabling broaching for long ducts. Becomes Also, since the volume of cutting chips in the chip storage is small, it is possible to prevent clogging of the broach blade and clogging of the broach in the duct, and the force required to pull out the broach can be reduced. Can be suppressed. Further, energy such as electric power used for processing can be saved. Further, since large cutting waste is not dragged by the broach, it is possible to reduce scratches on the cutting surface and obtain a high quality cutting surface. Therefore, it is possible to obtain a surface treatment method by broaching that corresponds to a long duct at low cost, and to obtain a beam duct for a charged particle accelerator with high performance.

[Brief description of drawings]

FIG. 1 is an explanatory view of a broach blade with a rectangular parallelepiped projection of the present invention.

FIG. 2 is an explanatory view showing a broach inside a workpiece.

FIG. 3 is an explanatory view of a broach blade with an integral type rectangular parallelepiped projection of the present invention.

FIG. 4 is an explanatory view showing a state of cutting with a broach blade with protrusions.

FIG. 5 is an explanatory view showing a state of cutting by a broach blade with a protrusion.

FIG. 6 is an explanatory view of an embodiment of a broach blade with protrusions of the present invention.

FIG. 7 is an explanatory view showing a broach in the object to be cut.

FIG. 8 is an explanatory view of a broach that supplies gas or liquid to the broach cutting surface of the present invention.

FIG. 9 is an explanatory view of an example of a vacuum duct used for the duct produced by the surface treatment of the present invention.

[Explanation of symbols]

1 ... Brooch blade, 2 ... Rectangular projection, 3 ... Broach blade rake face, 4 ... Broach axis, 5 ... Broach moving direction.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Hirano 502 Kintate-cho, Tsuchiura-shi, Ibaraki Prefecture Hiritsu Manufacturing Co., Ltd. Mechanical Research Laboratory

Claims (5)

[Claims] 1. A surface treatment method for cutting an inner surface of a duct or a pipe by broaching, wherein a broach blade having at least one protrusion is used on a rake face of the broach blade. 2. A surface treatment method for cutting an inner surface of a duct or a pipe by broaching, wherein a broach shaft of the broach to be broached is hollow, and at least one of the hollow portions is a through hole extending toward the rake face of the broach blade. A method for treating the inner surface of a duct, characterized by using a broach having a structure in which a gas or a fluid is jetted and collides with the broach blade rake face through the through hole. 3. The duct inner surface processing method according to claim 2, wherein the broach blade according to claim 1 is provided. 4. A vacuum container whose inner surface has been cut by the duct inner surface processing method according to claim 1, 2. 5. The beam duct of the charged particle accelerator according to claim 4, wherein the charged particles are accelerated inside the vacuum container.