JPS5852534B2 - Induction hardening equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction hardening device, and more particularly to a hardening device optimal for hardening a shaft having a rack.

When hardening the shaft by means of high frequency, the thickness of the hardened layer resulting from the hardening must be made axially symmetrically uniform.

For example, if the thickness of the hardened layer differs between one portion of the shaft and an axially symmetrical portion of the shaft, this will cause the shaft to warp.

For this reason, in conventional hardening methods, because the shape of the high-frequency coil is not symmetrical with respect to the axis of the shaft, the coil is moved along the shaft while being rotated relatively around the shaft. Hardening is performed so that the high-frequency electric field strength on the shaft surface is uniform.

By the way, when a shaft with a rack, such as a steering rack, is hardened using the method described above, the electric field concentrates on the peaks of the rack, and the bottom portions of the rack are not sufficiently hardened. As a result, the thickness of the hardened layer at the bottom portion of the rack becomes thinner than that at the shaft portion at the back of the rack, causing the shaft to warp.

The present invention has been made in view of the above-mentioned points, and when hardening a shaft having a rack, a high frequency coil is moved along the shaft in the portion of the shaft where the rack is provided, and in other portions of the shaft, a high frequency coil is moved along the shaft. The high frequency coil is rotated around the shaft.
To provide an induction hardening device capable of making uniform the thickness of each hardened layer on the rack part and the back surface thereof even in the rack part.

The present invention will be explained in detail below based on the accompanying drawings.

FIG. 1 is a diagram for explaining the present invention, and shows a shaft 1 having a rack and a high-frequency coil 2. The sectional view taken along the line AA' in FIG. B' cross-sectional views are shown in Figure 2, respectively.

The coil 2 is formed of a double-wound wire 3 made of copper or the like, and a part of the winding 3 is made of two concentric wires as shown in FIG. 2a (AA/sectional view). It is heavily wrapped.

Furthermore, a portion of the winding 3 is linear, and the linear portions are arranged in parallel in the longitudinal direction of the shaft 1, as shown in FIG. 2b (BB' sectional view).

Cores 4 and 5 made of silicon steel plate, ferrite, etc. are attached to the winding 3 of the straight portion, and the cores 4 and 5 made of silicon steel plate or ferrite are attached to strengthen the bond between the coil 2 and the material to be hardened. In order to increase the amount of magnetic flux interlinked with the material to be hardened, the high frequency coil 2 is supplied with high frequency from an appropriate power source, and the shaft 1 is further moved in its longitudinal direction, thereby hardening the shaft. It will be done.

When the rack 60 portion provided on the shaft 1 is hardened, the winding portion to which the cores 4 and 5 of the coil 2 are attached is placed close to the rack surface, and the shaft 1 has the core. The parts can be moved against the rack surface.

As a result, the amount of magnetic flux generated in the coil 2 interlinks with the rack 6 becomes extremely large, and the coupling between the rack 6 and the coil 2 becomes extremely large, and conversely, the back surface of the rack 6 separates from the winding 3 of the coil 2. The amount of interlinkage is small because it is located in a
The coupling between the back surface and the coil becomes smaller.

Therefore, in the rack portion, although the high frequency electric field is concentrated on the peaks of the rack, the bottom portions of the rack are also hardened due to the large bond, and the thickness of the hardened layer can be made approximately the same as the back surface of the rack.

When the hardening of the rack part is completed and the high-frequency coil 2 reaches the round bar part of the shaft 1 where no rack is provided, the shaft 1 is moved in the longitudinal direction and rotated, and as a result, the shaft 1 is rotated. A uniform high-frequency electric field is applied to the round bar portion 1, and the thickness of the cured layer can be made uniform.

FIG. 3 shows an embodiment of the induction hardening apparatus according to the present invention, and 11 is a shaft on which a rack 12 is provided.

The shaft 11 is supported by support rods 13 and 14, and the support rod 13 is rotatable by a motor 15.

The support rod 14 and the motor 15 are fixed on a moving table 16, and the moving table 16 is moved in the direction of the arrow in the figure by a feed screw 18 rotated by a motor 17.

An auxiliary member 20 having a light passage hole 19 is fixed to the movable table 16 at a position corresponding to a boundary position P between the portion of the shaft 11 where the rack 12 is provided and the round bar portion.

Furthermore, a high frequency coil 21 is arranged around the shaft 110 and is fixed independently to the moving table 16.
At a position corresponding to the coil, a lamp 22 and a photodetector 23 such as a photodiode are provided with an auxiliary member 20 in between.

In the configuration as described above, the shaft 11 provided with the rack 12 which is the material to be hardened is connected to the support rods 13 and 14.
Hardening of the shaft 11 is started by supporting the shaft 11 and supplying high frequency waves to the high frequency coil 21 from an appropriate power source.

The shaft 11 is hardened starting from the lower part in the figure where the rack is provided, and is hardened successively as the moving table 16 moves in the direction of the arrow.

When the rack part is hardened, the connection between the rack part and the coil is made larger as explained in FIGS. 1 and 2, and the connection with the coil is made smaller on the back of the rack. The thickness of the resulting cured layer can be made approximately uniform.

As the moving table 16 moves, the boundary position P of the shaft 11
When the light from the lamp 22 reaches the position of the coil 21, the light from the lamp 22 passes through the light passage hole 19 of the auxiliary member 20 and is detected by the photodetector 23.

The detected signal is supplied to the motor 15, which rotates the support rod 13 according to the detected signal, so that the shaft 11 rotates.

As a result, since the shaft 11 is rotated relative to the coil 21 when hardening the round bar portion of the shaft 11 where the rack 12 is not provided, a uniform high-frequency electric field is applied to the shaft surface, and the thickness of the hardened layer is uniform. You can make it like this.

Although the present invention has been described in detail above, the present invention is not limited to the embodiments described above and can be modified in many ways.

For example, the shape of the high frequency coil does not need to be double winding as shown in FIG. 1, and the core is not necessarily required.

Furthermore, although the boundary position P of the shaft 11 is detected photoelectrically in the embodiment shown in FIG. 3, it may also be detected mechanically using a microswitch or the like, or the shaft may be moved in a fixed direction. However, the high frequency coil may be moved.

Furthermore, when the shaft hardening is started from the part where the rack is installed and the round bar part is hardened, the shaft is rotated. The rotation of the shaft may be stopped upon detection of P, and then the rack portion may be hardened.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a shaft and a high-frequency coil for explaining the present invention, and Fig. 2 a and b are respectively A-A' in Fig. 1.
A sectional view, a BB' sectional view, and FIG. 3 are diagrams showing an induction hardening apparatus based on the present invention. 1.11...Shaft, 2.21...High frequency coil, 4.5...Core, 6,12...Rack, 13.1
4... Support rod, 15, 17... Motor, 16...
Moving table, 18... Feed screw, 19... Light passage hole, 2
0... Auxiliary member, 22... Lamp, 23... Photodetector.

Claims (1)

[Claims] 1. A high-frequency coil arranged around a shaft having a rack, a driving means for moving the shaft relative to the coil, a rotating means for rotating the shaft with respect to the coil, a detection means for detecting that the boundary rotation between the portion of the shaft where the rack is provided and the round bar portion has reached the coil position; a signal from the detection means;
An induction hardening device characterized in that the shaft is rotated or rotation of the shaft is stopped. 2. A high-frequency coil disposed around a shaft having a rack, a driving means for moving the shaft relative to the coil, a rotating means for rotating the shaft relative to the coil, and a rack for the shaft. a detection means for detecting that the boundary position between the round bar portion and the round bar portion has reached the coil position; and a signal from the detection means;
An induction hardening device characterized in that the shaft is rotated or the rotation of the shaft is stopped, the coil is composed of a winding wire wound at least twice, and the coil further comprises: The shaft has a linear portion arranged opposite to the rack surface of the shaft, and a portion where windings are wound substantially concentrically on the same plane, and in the linear portion, the shaft is An induction hardening device characterized in that a winding is wound evenly in the direction of movement relative to the coil. 3. The induction hardening device according to claim 2, wherein a core is provided in the linear portion of the coil.