JPH033566Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electrical heating device used for preheating as a pretreatment when remelting and hardening the surface of an iron-based member or the like.

(Prior art) In remelting and hardening treatment, which remelts the cam lift part of a camshaft using plasma arc, etc., and rapidly cools and chills this part to improve wear resistance, it is necessary to uniformly melt and harden the part to be treated. In terms of efficiency, it is preferable to preheat the camshaft to about 200° C. to 450° C., and it is preferable to use an electrical heating device for this preheating.

A pair of current heating devices are usually prepared, and each is attached to the rod of the cylinder unit, and when the cylinder unit operates, it holds both ends of the camshaft, and this state brings the electrodes in the current heating device into contact with the camshaft, causing the camshaft to It is configured to heat it by applying electricity.

(Problems to be Solved by the Invention) However, in the prior art described above, the end face of the camshaft is pressed against the electrode, or the periphery of the end of the camshaft is clamped with a clamp-type electrode to bring the electrode into contact with the camshaft, and then energization is carried out. However, in this conventional technology, oxides, oil and fat residues adhere to the contact surface between the electrode and the workpiece, and these deposits increase electrical resistance, leading to localized overheating and heating. As a result, the electrodes deteriorate prematurely, resulting in reduced durability and the need for frequent replacement of the electrodes.

The present invention was developed to solve the above-mentioned problems, and its purpose is to prevent deposits from entering the current-carrying part between the electrode and the workpiece contact part,
Stabilization of current flow, stabilization of heating temperature and life of electrodes,
An object of the present invention is to provide an electrical heating device with improved durability.

(Means for Solving the Problems) A means for solving the above problems is to use an electric current heating device that heats the workpiece by holding the edge circumference of the workpiece and applying electricity. The electrode part that contacts the member is divided into a plurality of parts, the base contact part of the electrode part that contacts the part that surrounds and holds the electrode part is swingably arcuate, and the tip of the electrode part that contacts the member to be processed is This means that the part is elastically biased so as to be located inside the contact part of the material to be treated.

(Operation by the above means) According to the above means, the tip of the electrode that contacts the member to be processed is elastically biased so as to be located inside the contact portion of the end of the member, and the electrode has an arcuate base and swings. Since it is flexible, when the end of the member to be processed is inserted and held in the electrode tip in the axial direction, the edge of the electrode tip rubs the circumference of the end of the member, removing deposits.

(Embodiment) Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional side view of the electrical heating device according to the present invention, and FIG. 2 is a front view thereof.

The energizing heating device 1 is fixed to the tip of a piston rod 10 of a cylinder unit (not shown) that moves back and forth.
A base 2 is provided. The base 2 has a cylindrical shape and includes a radially extending flange portion 2a at the rear.
a is screwed onto the distal end surface 10a of the piston rod 10, and the base 2 is integrally connected to the piston rod 10.

A flange portion 2b with a thick wall and a large diameter in the axial direction is formed at the tip of the base 2, and a screw 2c is provided on the outer periphery of the flange portion 2b, and a cylindrical cap 3 is attached to the outer periphery via a screw 3a on the inner diameter portion. are screwed together, and the cap 3
is extended forward. A ring-shaped current-carrying plate 4 made of copper or the like is attached to the radially outward peripheral portion of the front end surface 2d of the front flange portion 2b of the base 2 via a stepped portion 2e. A ring-shaped locking portion 3b is provided at the front end of the cap 3, and the front end everted portion 5b of the guide ring 5 is fitted in the axial direction with the locking portion 3b. The rear end 5c of the guide ring 5 is brought into engagement and abutment with the outermost peripheral step 2f of the flange portion 2b.

A core bar 6 is inserted through the axial inner diameter hole 2g of the base 2 and the inner diameter hole 10b of the piston rod 10,
The core bar 6 protrudes forward from the front end surface 2d of the base 2, and in the embodiment, the protruding end has three extending parts radially extending outward in the radial direction as shown in FIG. 2 to form a regulating arm 6a. ... is formed, and the regulating arm 6a...
... faces the inside of the guide ring 5 in the radial direction. A cooling air passage 6 in the axial direction is provided in the center of the core metal 6.
c is formed, and the passage 6c opens at the central end surface of the base 6b of the arm 6a..., and is provided with a branch passage 6d extending in the radial direction on the back side of the arm 6a... It communicates between the two and cools the rear surface of the base of the electrode portion, which will be described later.

The base portion 7a of the electrode 7 faces the space inside the guide ring 5 in front of the flange portion 2b, and the electrode 7
In the example, it is divided into three parts in the same direction, 7A, 7
B and 7C each form a fan shape with equal angles when viewed from the front. The base portion 7a of each electrode has an outer side portion 7b that comes into contact with the back surface of the locking edge 5d protruding in the inner diameter direction formed at the front end of the guide ring 5, the inner diameter portion 5e of the guide ring 5, and the surface 4a of the conductive plate 4, so that the outer circumference and Front and rear surfaces 7c in the axial direction
is formed in an arc shape. Step portions 7f, 7f formed at both ends of the inner diameter portion 7d of the base portion 7a are connected to the arms 6a...
The intermediate portion 7e between the shaft portions 7f and 7f is located inward from the tip portion of the arm. The tip portion 7g of each electrode 7 has an inverted L-shaped cross section, and is provided with a claw-like tip portion 7h that projects forward from the intermediate portion 7e. The inner surface tips 7i of the inner surfaces 7i protrude slightly inwardly.
The distal ends thereof are each inclined outward in the radial direction to form a tapered distal end portion 7j.

The above tip 7h is a separate electrode piece 7 in the embodiment.
1, and the electrode including the piece 71 is substantially one piece. A locking step 7k is formed on the outer periphery of the claw-like tip 7h, and a ring-shaped stepped heating material 8, for example, made of asbestos, is wound around the circumference of the claw-like tip and is locked at the step 7k. A ring-shaped spring 9 is wound around the outer periphery of the stepped heating material 8 to bias the three claw-like tips 7h . . . inward in the radial direction. Each electrode 7...
Although the claw-like tips 7h... are urged inward in the radial direction, the outer periphery of the base 7a comes into contact with the surrounding wall surface, and the spring 9
By setting the spring load, the inner tip 7i of the claw-like tip is located radially inward than the outer shape of the end _W1 of the workpiece W such as a camshaft,
Its position is indicated by the chain line A in FIG.

In the above, the energizing device 1 is approached from the axial direction of the end W1 of the workpiece W through the piston rod ₁₀ , and the claw-like tips 7 of the electrodes ₇ are placed around the end W1.
The tip tapered part 7j of the tip 7j hits, and as the electrode 7 advances further, the base 7a surface 7c is arcuate, so it swings while contacting the surrounding walls 5d, 5e, 4a, and expands against the spring 9. and comes into contact with the peripheral surface of the end _W1 . The peripheral surface of the end comes into contact with the front end surface of the tip 7g in the inner diameter direction of the base while contacting the inner surface tip 7i of the claw-like tip 7h, and is regulated there, stopping the movement of the device, and in this process, the end W The adhesion on the surface of _one circumference is rubbed and removed, and it adheres to the front end surface of the claw-like tip 7h, and the end that is the contact part
There is no deposit between the _W1 circumferential surface and the inner surface tip 7i, and electricity is applied through this contact portion to perform heating.

(Effects of the invention) As is clear from the above, according to the invention, when the end of the workpiece is fitted and held in contact with the tip of the divided claw-like electrode, the friction between the end and the electrode is reduced. As a result, oxides and oils and fats attached to the circumference of the end are peeled off and removed, making it possible to conduct electricity stably and reliably, stabilizing uniform heating, and suppressing power consumption. This can be realized with a simple configuration that makes arcuate contact with the outer wall surrounding the claw-shaped electrode base and presses it inward with a spring.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional side view of an electrical heating device, and FIG. 2 is a front view thereof. In the drawing, 7 is an electrode, 7a is a base contact portion, 7c is an arcuate portion, 7h is a tip, 7i is a contacting tip, and 9 is an elastic urging member.

Claims (1)

[Scope of utility model registration request] In an electrical heating device that heats a workpiece by holding the end circumference of the workpiece and applying electricity, an electrode part that comes into contact with the workpiece is divided into a plurality of parts, and the electrode part is in contact with a part that surrounds and holds the workpiece. The base contact portion of the electrode portion is swingably arcuate, and the tip portion of the electrode portion that contacts the member to be processed is elastically biased so as to be located inside the contact portion of the member to be processed. Electrical heating device.