JPH0714356Y2 - High frequency heating coil - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention, for example, forms a hardened layer only on the tooth tips of a ball screw, or shallowly quenches the surface of a work such as a long cylindrical shaft. The present invention relates to a high-frequency heating coil (hereinafter, simply referred to as a heating coil) suitable for performing.

<Prior Art> A conventional technology will be described below with reference to the drawings. FIG. 4 is a view for explaining a conventional heating coil.
Figure (a) is a partial vertical front view of the ball screw, and Figure 4 (b).
FIG. 3 is a perspective view of a ball screw (however, the description of the screw thread is omitted) and a heating coil.

To form a hardened layer having a uniform depth on the entire tooth surface on the surface of the ball screw 1 as shown in FIG. 4 (a), as shown in FIG. 4 (b), a saddle type semi-open type The heating coil 3 is placed on the ball screw 1, and the heating coil 3 is energized to move the heating coil 3 in the longitudinal direction of the ball screw 1 while rotating around the longitudinal direction of the ball screw 1. Then,
Mainly in the longitudinal direction 1 of the ball screw 1 of the heating coil 3.
A current flowing in the direction of arrow A flows on the surface of the ball screw 1 by the current flowing through the pair of conductors 31 and 32. Therefore, the hardened layer 2 having a uniform depth should be formed on the entire tooth surface of the ball screw 1. You can At this time, the length of the conductor 31 is usually set to l ≧ 0.7D.
As a result, the heating effect by the current flowing through the conductor 31 (the induced current flowing in the longitudinal direction of the ball screw 1) is increased.

<Problems to be Solved by the Invention> However, in some cases, it may be required to form a hardened layer only on the tip portion of the screw of the ball screw 1. Further, even in the case of a long cylindrical shaft, it is sometimes required to form a hardened layer which is much shallower than usual. In such a case, when the ball screw 1 or the long cylindrical shaft is hardened by the above-mentioned conventional saddle-shaped half-open type heating coil 3, the hardened layer 2 is also formed in the valley of the screw in the ball screw 1. In addition, a shallow hardened layer cannot be formed on the shaft having a long cylindrical shape.

The present invention has been made in view of the above circumstances. For example, in quenching a ball screw, a hardened layer can be formed only on the tip portion of the screw, and in a long cylindrical shaft or the like. Aims to provide a heating coil capable of forming an extremely shallow hardened layer.

<Means for Solving the Problem> In order to solve the above problem, the heating coil according to claim 1 is arranged so as to be parallel to the longitudinal direction of the work such as a ball screw or a long cylindrical shaft and approach and face the work. A pair of linear first and second conductors, which are arranged in a line, and one ends of the first and second conductors are connected to each other, and are arranged so as to approach the work and straddle the work. A semi-circular third conductor, and a substantially semi-circular fourth conductor that connects the other ends of the first and second conductors and is arranged so as to approach the work and straddle the work. In the saddle-shaped semi-open type heating coil having, the length of the first and second conductors is l, and the diameter of the work is D, 1 ≦ 0.5D.

A heating coil according to a second aspect of the present invention is the heating coil according to the first aspect, wherein one end and the other end of the first conductor are respectively a fifth and a second conductor so that the first conductor and the second conductor are separated from the work. The third and fourth conductors are connected to one ends of the third and fourth conductors via the sixth conductor, and the one and other ends of the second conductor are connected to the third and fourth conductors via the seventh and eighth conductors, respectively. Connected to the end.

<Operation> Therefore, when a work such as a ball screw or a long cylindrical shaft is heated using the heating coil according to claim 1, the length of the first and second conductors is short, so that the length of the work is long. The generation of the induced current flowing in the direction is small, the induced current in the circumferential direction of the work is large due to the third and fourth conductors, and the heating of the work is mainly performed by the induced current in the circumferential direction.

Furthermore, when the heating coil according to claim 2 is used, since the first and second conductors are separated from the work, the generation of induced current flowing in the longitudinal direction of the work is extremely small,
Since the induced currents in the circumferential direction of the work by the third and fourth conductors are almost the same, the heating of the work is performed by the induced currents in the circumferential direction of the work. Therefore, whichever heating coil is used, the ball screw has a hardened layer formed only on the tooth tips of the screw, and a shallow hardened layer is formed on the surface of the work such as the long cylindrical shaft. .

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 3 to FIG. 3 are drawings for explaining an embodiment of the present invention, in which the ball screw of FIG. 1 (however, the description of the screw thread is omitted) and the heating coil of the first embodiment are shown. FIG. 2 is a perspective view of the ball screw and the heating coil of the second embodiment, and FIG. 3 is a partial vertical sectional front view of the ball screw.

First, the first embodiment will be described. As shown in FIG. 1, the heating coil 5 of this embodiment is a saddle-shaped semi-open type coil, and the heating coil 5 includes a pair of linear conductors 51 (first coil) parallel to the longitudinal direction of the ball screw 1. Conductors), 52 (second conductors), and substantially semicircular conductors 53 (third conductors) formed so as to connect opposite ends of these conductors and to approach and cross the workpiece 1. Conductor) and a substantially semicircular conductor 54 (fourth conductor) formed so as to connect the opposite ends of the conductors 51 and 52 to each other and to approach and cross the work 1. ing. The central portion of the conductor 54 is connected to the divided high frequency power supply 100. The conductors 51, 52 are of equal length,
The length l is l when the diameter of the ball screw 1 is D.
It is formed such that ≦ 0.5D.

Now, while rotating the work 1 about its longitudinal direction as an axis, a high-frequency current is passed from the high-frequency power supply 100 to the heating coil 5, and the heating coil 5 is placed on the work 1.
The conductors 51, 52 of the heating coil 5 when moving in the longitudinal direction of
Are conductors 31 and 32 of the conventional heating coil 3 described in FIG.
In comparison with the conventional heating coil 3, when the workpiece 1 having the same diameter D is quenched, the induced current in the workpiece 1 in the longitudinal direction is smaller than that in the conventional heating coil 3. Therefore, work 1
The surface of is heated mainly by the induction current in the circumferential direction of the work 1 due to the high frequency current flowing in the conductors 53, 54 of the heating coil 5.

Therefore, as shown in FIG. 3, the ball screw 1 quenched by the heating coil 5 has the hardened layer 9 formed only on the tooth tips. If the work 1 is a work such as a long cylindrical shaft, a hardened layer is formed shallowly on the surface.

Next, a second embodiment will be described.

As shown in FIG. 2, the heating coil 7 of this embodiment is also a saddle type semi-open type heating coil, and the heating coil 7 is connected to the conductors 51, 52, 53 and 54 of the heating coil 5 described in FIG. Conductor 71,
72, 73, 74 are supported. However, the heating coil 7 is different from the heating coil 5 in that the conductors 71 and 72 are separated from the surface of the work 1. That is, between one end of the conductor 71 and the conductor 73, between the other end of the conductor 71 and the conductor 74, between one end of the conductor 72 and the conductor 73, between the other end of the conductor 72 and the other end of the conductor 74, respectively, straight lines Conductors 75 (fifth conductor), 76 (sixth conductor), 77 (seventh conductor), 78 (eighth conductor) are provided. And conductors 75, 76, 77, 78 are typically conductors 71 and 72.
Are placed on the plane formed by and, and the conductors 75, 76, 7
The lengths of 7 and 78 are selected so that heating of the work 1 by the conductors 71 and 72 is extremely small.

When quenching the work 1 using the heating coil 7 in the same manner as when quenching the work 1 using the heating coil 5, as compared with the conductors 31 and 32 of the conventional heating coil 3, Conductors 71, 72 of the conductor 1 are almost conductors 75, 7
The conductors 71 and 72 are separated by a length of 6, 77 or 78
The induced current in the longitudinal direction of the work 1 caused by the and is extremely small. Therefore, the surface of the work 1 is heated mainly by the induction current in the circumferential direction of the work 1 due to the high frequency current flowing in the conductors 73 and 74 of the heating coil 7.

Therefore, the hardened layer 9 is formed only on the tooth tip portion of the ball screw 1 quenched by the heating coil 7 as shown in FIG. 3 similarly to the first embodiment. If the work 1 is a work such as a long cylindrical shaft, a hardened layer is formed shallowly on the surface.

Although the heating coil was moved during quenching of the work by the heating coil of the present embodiment, the work may be moved.

<Effect of the Invention> As described above, in the heating coil according to the first aspect, the length of the conductor in the longitudinal direction of the work is 0.5 of the length of the diameter of the work.
In the heating coil according to the second aspect of the present invention, the length of the conductor in the longitudinal direction of the work is 0.5 times or less the length of the diameter of the work. Conductors are arranged so as to be separated from the surface of the work. Therefore, on the surface of the work, an induced current in the circumferential direction mainly flows due to a current flowing through a pair of substantially semicircular conductors formed by connecting conductors in the longitudinal direction of the work and straddling the work. Therefore, it is possible to form a hardened layer only on the tooth tips of the ball screw or an extremely shallow hardened layer on the surface of a work such as a long cylindrical shaft.

[Brief description of drawings]

1 to 3 are drawings for explaining an embodiment of the present invention, in which FIG. 1 shows a ball screw (however, a screw thread is not shown) and a heating coil of the first embodiment. Perspective view of
FIG. 2 is a perspective view of the ball screw and the heating coil of the second embodiment, and FIG. 3 is a partial vertical sectional front view of the ball screw. FIG. 4 is a drawing for explaining a conventional heating coil. FIG. 4 (a) is a partial vertical sectional front view of the ball screw 1, and FIG. 4 (b) is a ball screw (however, the description of the screw thread is omitted. FIG. 3 is a perspective view of a heating coil. 1 ... Workpiece, 5, 7 ... Heating coil, 51-54, 71-78
……conductor.

Claims (2)

[Scope of utility model registration request] 1. A pair of linear first and second conductors, such as a ball screw or a long cylindrical shaft, which are arranged parallel to the longitudinal direction of the work and close to and face the work. A substantially semi-circular third conductor that connects one ends of the first and second conductors and is arranged so as to approach the work and straddle the work, and the other ends of the first and second conductors A substantially semicircular fourth conductor that is connected to the workpiece and is disposed so as to approach the workpiece and straddle the workpiece. A high frequency heating coil, wherein l ≦ 0.5D, where l is the length and D is the diameter of the work. 2. One end and the other end of the first conductor are respectively connected to the third and fourth conductors via the fifth and sixth conductors so that the first and second conductors are separated from the work. The high frequency heating coil according to claim 1, wherein the high frequency heating coil is connected to one end, and one end and the other end of the second conductor are connected to the other ends of the third and fourth conductors through the seventh and eighth conductors, respectively.