JPH0761574B2 - Electrolytic polishing device for inner surface of pipe-shaped work - Google Patents

Description

The present invention relates to an electrolytic polishing apparatus for the inner surface of a pipe-shaped work.

(Prior Art) In order to perform electrolytic polishing on the inner surface of a pipe-shaped work, a rod-shaped machining electrode having an outer diameter slightly smaller than the inner diameter of the work is inserted between the work and the machining electrode. A common method was to apply a direct current to the. However, when the total length of the work becomes long and the length of the working electrode becomes large, the current density flowing from the working electrode to the work becomes non-uniform, and unevenness in the finish tends to occur. For this reason, when electrolytically polishing the inner surface of a pipe-shaped work with a large overall length, a method is also used in which an electric current is passed while sequentially moving the machining electrodes. I couldn't.

(Problems to be Solved by the Invention) The present invention solves the conventional problems as described above, and the inner surface of a pipe can be uniformly electrolytically polished even when the total length of the work is long, and the inner surface of the work is pipe-shaped. It was completed for the purpose of electropolishing equipment.

(Means for Solving Problems) In the present invention, a plurality of cylindrical electrodes having an outer diameter smaller than the inner diameter of a pipe-shaped work are connected in the axial direction of the work with an insulating ring interposed therebetween. A machining electrode, a power feeding electrode that is brought into contact with the outer surface of the work corresponding to the position of each cylindrical electrode, a pulse power source having a plurality of negative side terminals that sequentially apply a pulse current to each cylindrical electrode, and a plurality of pulse power sources. And a cord wire connecting each of the cylindrical electrodes.

(Example) Next, the present invention will be described in detail with reference to the illustrated example.
(1) and (2) are caps for supporting both ends of the pipe-shaped work (30), and (3) is provided with a pin-shaped projection (4) at the tip to be inserted into the center hole of the cap (1). It is a hollow tube, and a processing electrode composed of a plurality of cylindrical electrodes (5) and an insulating ring (6) is formed around the hollow tube (3). The cylindrical electrode (5) has an outer diameter slightly smaller than the inner diameter of the pipe-shaped work (30), and is divided into connections in the axial direction of the work (30). The insulating ring (6) is interposed between the tubular electrodes (5), (5) to insulate the tubular electrode (5), and in the illustrated embodiment, the insulating ring (6) serves as a holder for the tubular electrode (5). It also plays a role. If the distance between the cylindrical electrodes (5) exceeds several mm, the current density becomes non-uniform, so the distance should be within several mm. Reference numeral (7) is a power feeding electrode that is brought into contact with the outer surface of the pipe-shaped work (30), and is arranged in the axial direction of the work (30) so as to correspond to the positions of the individual cylindrical electrodes (5) and (5). Divide into multiple pieces.

In the present invention, a pulse power source (9) having a plurality of negative side terminals (8) is used to supply a current for electrolytic polishing to these working electrode and power feeding electrode (7). The pulse power source (9) has a function of sequentially distributing pulses generated at fixed time intervals to each negative side terminal (8) by a switching circuit having a built-in switching circuit. (5) are individually connected via a cord wire (10) as shown in the figure. The positive terminal (11) of the pulse power supply (9) is connected to the cord wire (1
It is connected to the feeding electrode (7) via 2). The mouthpieces (1) and (2) have an outlet (13) for electrolyte as shown in the figure.
And an inlet (14) are formed so that the electrolytic solution can flow through the gap between the machining electrode and the work (30).

(Operation) As shown in the figure, the structure is such that the pipe-shaped work (30) is fixed between the mouthpieces (1) and (2), and the cylindrical electrode (5) and the insulating ring (6) are provided. A machining electrode composed of is placed inside the work (30), and the feed electrode (7) is brought into contact with the outer surface of the work (30) so as to correspond to the positions of the individual cylindrical electrodes (5) and (5). . In this state, the electrolytic solution is capped with a circulation pump (not shown) (2)
Supply from the inlet (14) and pulse power supply (9)
A pulse current is sequentially generated at each minus side terminal (8) of each of the cylindrical electrodes (5), through the cord wire (10),
By energizing (5), each cylindrical electrode (5) and work (30)
The electrolytic polishing is sequentially performed between the inner surface of the work (30) and the inner surface of the work (30). In the present invention, since electrolytic polishing is performed by the cylindrical electrode (5) divided into a plurality of pieces in this way and having a short axial length, uneven current density does not occur, and each cylindrical electrode ( 5)
Since a pulse current is sequentially applied to the workpiece under the same conditions, a uniform finished state can be obtained over the entire length of the work (30). Moreover, in the present invention, since electrolytic polishing is performed by the pulse power source (9), the system is stabilized by utilizing the quiescent period of the current, which is higher than that in the case where a direct current is constantly applied. Efficient electropolishing can be performed by the density current.

(Effects of the Invention) As is apparent from the above description, the present invention employs a method of sequentially applying a pulse current to a plurality of cylindrical electrodes that are disassembled in the axial direction, so that a pipe-shaped work having a large total length can be obtained. The inner surface of the electrode can also be electrolytically polished uniformly, and it is not necessary to perform electrolytic polishing while moving the processing electrode as in the conventional case, so that there is an advantage that the processing efficiency can be remarkably improved. However, it is needless to say that the machining electrode can be moved in the longitudinal direction of the workpiece even when the apparatus of the present invention is used. Therefore, the present invention has an extremely great contribution to the industry as an electrolytic polishing apparatus for the inner surface of a pipe-shaped work which solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. (5): Cylindrical electrode, (6): Insulating ring, (7): Power feeding electrode, (8): Negative side terminal, (9): Pulse power supply,
Code wire (10), (30): Work

Claims (1)

[Claims] 1. An axial direction of a work (30) with a plurality of cylindrical electrodes (5) having an outer diameter smaller than the inner diameter of a pipe-shaped work (30) with an insulating ring (6) interposed therebetween. A machining electrode connected to the above, and a feeding electrode (7) abutting on the outer surface of the work (30) corresponding to the position of each cylindrical electrode (5),
A pulse power supply (9) having a plurality of negative side terminals (8) for sequentially applying a pulse current to each cylindrical electrode (5), and connecting the plurality of negative side terminals (8) and each cylindrical electrode (5). An electrolytic polishing apparatus for the inner surface of a pipe-shaped workpiece, which is equipped with a cord wire (10).