JPS63230818A - Method and apparatus for quenching by high frequency - Google Patents

Abstract

PURPOSE:To increase heating power and to enable high frequency quenching for a short time by quenching a work by a heating coil, which is sealed to magnetic field at the upper and lower faces thereof, and injecting cooling water from water cooled jacket adjoining to the coil. CONSTITUTION:The work, such as cam shaft 6, is inserted into the heating coil 1 and high frequency power is impressed to the heating coil 1, and the cam shaft 6 and coil 1 and the water cooled jacket 4 connected it, are relatively shifted. Then, on the upper and lower faces of the heating coil 1, a magnetic sealed plate 3 is arranged to shut out line of magnetic force 2 generated toward vertical direction of the coil 1 and to prevent the part already quenched from tempering by reheating and also to shorten the quenching time by increasing heating output. When the cam shaft 6 quenched by the coil 1 is reached to the water cooled jacket 4, it is cooled by cooling water injected from injecting holes 4a and the shifting of heat at the presently quenched part is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an induction hardening method and a hardening apparatus for hardening a camshaft mainly used in an internal combustion engine.

(Prior Art) A camshaft a conventionally used in an internal combustion engine has a structure in which a plurality of cams C and journals d are provided at intervals in the axial direction on the shaft portion, as shown in Fig. 2. .

In addition, when induction hardening the camshaft a as described above, the camshaft a is positioned at the center of the heating coil e, and the heating coil e or the camshaft a is moved in the direction of the arrow while supplying power to the heating coil e. As a result, the surface of the camshaft a is induction hardened.

(Problems to be solved by the invention) The above conventional induction hardening! At IN, the heating output is increased to prevent the camshaft a from burning out.

However, when the heating output is increased, the magnetic lines of force f generated by the heating coil e reach the part that has already been hardened, and as a result, the hardened part becomes tempered and the desired hardening effect cannot be obtained. Therefore, it was not possible to increase the heating output much with conventional quenching equipment. For this reason, the quenching and quenching took a long time, resulting in poor productivity and other problems such as burn cracks and thermal distortion.

This invention was made for the purpose of improving the above-mentioned problems.

(Means and effects for solving the problems) The present invention has been made in view of the above points, and the present invention is made by applying a high frequency power to a heating coil provided with magnetic shield plates on the upper and lower surfaces, and The workpiece to be hardened is moved relatively into the heating coil while preventing magnetic lines of force from leaking in the vertical direction of the heating coil, and the workpiece is hardened by the heating coil. By squirting cooling water onto the hardened part and hardening the entire workpiece while preventing the hardened part from tempering, induction hardening can be performed in a short time without tempering the hardened part.

In addition, magnetic shield plates are provided on the upper and lower surfaces of the heating coil, and a water cooling jacket is provided adjacent to the heating coil to increase heating output and enable induction hardening to be performed efficiently in a short time.

(Example) An example of the induction hardening method and hardening apparatus of the present invention will be described in detail with reference to FIG.

In the figure, reference numeral 1 denotes a cylindrical heating coil to which high frequency power is applied from a high frequency power source (not shown), and magnetic shields are provided on the upper and lower surfaces of the heating coil 1 to prevent leakage of magnetic lines of force 2. Temporary 3 is installed. The magnetic shield plate 3 is formed from a pure iron punch, and when the heating output of the heating coil 1 is increased, it blocks the lines of magnetic force 2 that are generated in the vertical direction of the heating coil 1, and prevents the part that has already been hardened. It has a function to prevent magnetic force &II2 from being applied to.

Further, a cylindrical water cooling jacket 4 is provided below the heating coil 1 concentrically with the heating coil 1.

The water cooling jacket 4 is connected to a cooling water source (not shown) via a pipe line 5, and has a large number of cooling water jet holes 4a opened in the inner surface of the water cooling jacket 4 to receive cooling water supplied from the cooling water source. is spouted toward the camshaft 6 from these cooling water spout ports 4a.

Next, a method for induction hardening the camshaft 6 using the above-mentioned induction hardening apparatus will be described in detail.

The camshaft 6 to be hardened is housed in the heating coil 1 so that its shaft center is almost flush with the center of the heating coil 1. In this state, high frequency power is applied to the heating coil 1, and the camshaft 6 is heated from the lower end side. Move the heating coil 1 and water cooling jacket 4 toward the upper end.

Alternatively, the camshaft 6 is moved from above to below while the heating coil 1 and water cooling jacket 4 are fixed.

Furthermore, even if the heating output is increased to prevent burnout, the lines of magnetic force 2 generated in the vertical direction of the heating coil 1 are blocked by the magnetic shield plate 3 and do not reach the already hardened portion.

It is possible to prevent the hardened portion from being reheated and tempered, and at the same time, by increasing the heating output, the hardening time can be shortened.

On the other hand, as the high frequency coil l or the camshaft 6 moves,
The part heated and hardened by the heating coil 1 is heated by the heating coil 1.
The cooling water reaches the inside of the cooling water jacket 4 provided below and is cooled by the cooling water jetted from the cooling water jet holes 4a opened on the inner peripheral surface.

As a result, the heat of the portion currently heated by the heating coil 1 is thermally conducted within the shaft portion 6a of the camshaft 6 and reaches the cam 6b and journal 6c, which have already been hardened.
These can be prevented from being tempered.

When the heating coil 1 has been hardened to the upper end of the camshaft 6, the camshaft 6 is taken out from inside the heating coil 1, so that the hardening of the camshaft 6 can be completed in a short time.

Incidentally, the hardening of the camshaft 6, which took 8 seconds with a conventional hardening device, can be completed in 2 to 3 seconds with the method and device of the present invention, making it possible to significantly shorten the hardening time.

In addition, although the case where the camshaft 6 was induction hardened was explained in the said Example, it is not limited to the camshaft 6 as long as it is a one-ring shape.

(Effects of the Invention) As described in detail above, this invention is capable of hardening the camshaft, etc. while preventing the leakage of magnetic lines of force using the magnetic shield plates provided on the upper and lower surfaces of the heating coil, thereby increasing the heating output. However, the lines of magnetic force do not reach the parts that have already been hardened.

This makes it possible to eliminate problems such as the hardened portion being tempered, and also to improve productivity because the hardening time is significantly shortened by increasing the heating output.

In addition, cooling water is jetted from the water-cooling jacket installed adjacent to the heating coil to the part that has already been quenched to cool the part that has already been quenched. It is also possible to eliminate problems such as heat conduction to the hardened parts and tempering of the hardened parts.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is a conventional explanatory diagram. 1...Heating coil, 2...Magnetic field lines. 3...Magnetic shield, 4...Cooling water jacket. Patent applicant: Komatsu Ltd. Agent (patent attorney) Osamu Matsuzawa Figure 1 Figure 2

Claims (2)

[Claims] (1) Heating coil 1 with magnetic shield plates 3 provided on the upper and lower surfaces
A high frequency power source is applied to the magnetic shield plate 3 to prevent the lines of magnetic force 2 from leaking in the vertical direction of the heating coil 1, while moving the workpiece to be hardened into the heating coil 1 relatively. In addition to hardening the workpiece, cooling water is jetted from the cooling water jacket 4 adjacent to the heating coil 1 to the already hardened part to harden the entire workpiece while preventing the hardened part from being tempered. Characteristic induction hardening method. (2) A magnetic shield plate 3 is provided on the upper and lower surfaces to prevent leakage of magnetic lines of force 2, and a heating coil 1 to which a high frequency power source is applied is provided adjacent to the heating coil 1 and is already connected to the heating coil 1. An induction hardening device comprising a cooling water jacket 4 that jets cooling water to the hardened part.