JPH017713Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction hardening device for a steering rack of a rack and pinion type steering device for an automobile.

As shown in FIG. 3, this type of induction hardening apparatus for steering racks includes electrodes 5, which are in contact with both ends 3, 4 of the rack teeth 2 of the steering rack 1;
6, and a holding member 9 for holding the back side of the steering rack 1 provided on the pressing devices 7 and 8, such as fluid pressure cylinders, located opposite to the electrodes 5 and 6.
10, the steering rack 1 is clamped and fixed. Therefore, the rack teeth 2 are held in a restrained state by the electrodes 5 and 6 that are in contact with the steering rack and the holding members 9 and 10 that are positioned opposite to them. Thermal expansion occurs during heating, but especially the thermal expansion in the axial direction is restrained at the clamping and fixing position, and due to the influence of the restrained thermal expansion, the distortion of the rack tooth portion 2 becomes complicated and large in directions other than the axial direction. Subsequent correction work is difficult, work efficiency is poor, and manufacturing costs are increased.

An object of the present invention is to provide an induction hardening device for a steering rack that can reduce the distortion on both sides of the rack teeth of the steering rack and make the direction of the distortion substantially unidirectional, thereby facilitating correction work. There is a particular thing.

Embodiments of the present invention will be described below with reference to FIGS. 1 and 3.

A conductor 13 is arranged in parallel above the conductor 11 via an electrical insulator 12, and a rectangular parallelepiped-shaped induction coil 14 facing the rack teeth 2 of the steering rack 1 is fixed above the conductor 11. One electrode 5 is connected to the screw 15 adjacent to both ends of the
The other electrode 6 is also fixed to the conductor 13 in the same manner as the electrode 5, and the electrodes 5 and 6 have both ends 3 of the rack teeth 2 of the steering rack. . 9 and 10 are provided to clamp and fix the steering rack 1, and both ends 3,
4 and the electrodes 5 and 6 are pressed into contact with each other, and the conductor 11
A high frequency power source 16 is connected to the conductor 13 to form a loop circuit, and a high frequency current from the high frequency power source 16 is supplied to the electrodes 5, 6 and the induction coil 14. Then, after heating the rack teeth, the induction coil 1
A coolant supply device 18 is provided for supplying a coolant such as water into the induction coil 14 so as to jet the coolant such as water from a small hole 17 provided on the opposite surface of the induction coil 14 . Up to this point, the configuration is the same as that of the conventional device.

L-shaped members 19 and 20 are positioned opposite to each other on both sides between the rack teeth of the steering rack 1 mounted on the device, and the bolt 2 is placed above the conductor 11.
The L-shaped members 19, 20 are provided with elastic pressing members 22, 22, etc., which are fixed to the L-shaped members 19, 20 and are fixed to the L-shaped members 19, 20, and are fixed to the L-shaped members 19, 20, etc., and press into contact with both sides of the steering rack between the rack teeth. ... consists of a spring 23 with a predetermined load and a presser 24, and a plurality of elastic press members 22, 22... are provided in parallel with each other in opposing positions.

In this way, by providing the elastic pressing members in opposing positions that press into contact with both sides of the steering rack between the rack teeth, the rack teeth can be clamped and fixed between the electrode in contact with the steering rack and the holding member. Thermal expansion in the axial direction of the rack is restrained, and when the restrained thermal expansion tries to distort on both sides of the rack teeth, it is distorted by the springs of elastic pressing members placed opposite on both sides between the rack teeth. When the space between the rack teeth tends to be distorted toward the elastic pressing member, the elastic pressing member becomes larger than the set pressing load before distortion due to the amount of distortion, and prevents the distortion. In addition, in the elastic pressing member on the opposite side from the distortion, the pressing load is smaller than the set pressure load before distortion, and it works so as not to promote distortion, reducing the distortion on both sides of the steering rack and almost eliminating the distortion. Try to focus in one direction.

Figure 2a is a cross section of the rack tooth at right angles to the axis, and lines x-x', y-y', a-a', and b-b' passing through the axis indicate the distortion measurement positions; is a characteristic diagram showing the amount of distortion of the rack teeth at the measurement position obtained by randomly sampling the steering racks of the device of the present invention (solid line) and the conventional device (dashed line). From this, in the conventional device (dashed line), the thermal expansion is the largest due to heating of the rack teeth, and the thermal expansion is constrained in the y, a, and b directions, where the amount of distortion is large, and at both electrode positions, so the influence of It can be seen that the amount of distortion increases in the x and x' directions on both sides between the rack teeth. In the device of the present invention (solid line), the amount of distortion in the directions x and x' on both sides of the rack teeth is reduced, and the amount of distortion in the directions a and b of the rack teeth is also kept small, and the amount of distortion on the rear side a' of the rack teeth is kept small. ，
It can be seen that the amount of distortion in b' and y' is further suppressed, and the distortion is concentrated in the y direction at the center of the rack tooth.

This is due to the fact that a, b,
Since the thermal expansion of the rack teeth is restrained in the y direction and at both electrode positions, distortion in the x and x' directions due to thermal effects is prevented by elastic pressing members. By pressing x', the distortion is concentrated in the y direction at the center of the rack tooth part, and the distortion of the rack tooth part in the a, b, x, x', a', b', and y' directions is reduced. It is.

Since the device of the present invention has elastic pressing members placed facing each other in pressure contact with both sides of the steering rack between the rack teeth, distortion of both sides of the steering rack between the rack teeth due to thermal expansion during heating is avoided. can be made smaller and the direction of distortion can be made substantially in one direction, thereby making it possible to reduce distortion in other directions accordingly. Further, since complicated distortions can be prevented, the straightening work after hardening becomes easier, work efficiency can be improved, and manufacturing costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the device of the present invention, Fig. 2a is an explanatory view showing the distortion measurement position in a cross section perpendicular to the axis of the rack tooth portion, and Fig. 2b is an explanatory view showing the distortion measurement position in the axis-perpendicular cross section of the rack tooth portion. FIG. 3 is a characteristic line diagram showing the amount of distortion depending on the measurement position, and FIG. 3 is a partially cutaway front view showing a conventional device. Explanation of symbols, 1... Steering rack, 2...
...Rack tooth portion, 22...Elastic pressing member, 23...
Spring, 24...presser.

Claims (1)

[Scope of utility model registration request] an induction coil facing the rack teeth of the steering rack; electrodes adjacent to both ends of the induction coil and in contact with both ends of the rack teeth; a holding member located opposite the electrode; and the electrode and the induction coil. a high-frequency power supply that supplies high-frequency current to the coil;
A steering rack induction hardening device having a cooling liquid supply device for supplying cooling liquid into the induction coil, characterized in that pressing devices are provided on both sides between the rack teeth so as to face each other. induction hardening equipment.