JPH05105958A - Method and apparatus for high frequency induction heating to crank shaft - Google Patents

Abstract

PURPOSE:To reduce a strain in a crank shaft heating a pin. CONSTITUTION:During heating of the pin, a load applied on the pin is made to adjustable. A high frequency induction heating apparatus provides a sprocket 4 hanging down a current transformer 2 which fits a high frequency induction heating coil 1 at the lower part, with a chain 3, an eccentric cam 6 rotated by linking with a shaft 5 as parallel to the sprocket 4, a chain 7 stretching the eccentric cam 6 to the high frequency induction heating apparatus through a spring 8. The eccentric cam 6 is formed so as to be R>r2 and gradually and continuously change from R to r2 in the case of using R for the distance between the contact starting point 6a of the eccentric cam 6 when the pin P1 is the top dead center, with the chain 7 and the shaft 5, and in the case of using r2 for the distance between the contact starting point 6b of the eccentric cam 6 when the pin P1 is the bottom dead center, with the chain 7 and the shaft 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency heating apparatus for crankshafts, and more particularly to a high frequency heating apparatus for crankshaft pins.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings. 3 and 4 are drawings for explaining a conventional high-frequency heating method for a crankshaft, FIG. 3 is an explanatory view of a high-frequency heating apparatus for performing this method, and FIG. 4 is a front explanatory view of the crankshaft.

As the crankshaft, as shown in FIG. 4, a crankshaft 100 for a four cylinder engine is adopted. The crankshaft 100 has journals J1 to J5 and pins P1 to P4. The shaft 101 of the journals J1 to J5 is also the shaft of the crankshaft 100, that is, the shaft that is the center of rotation of the crankshaft 100. Ten
2 is, for example, an axis serving as the center of the pin P1.

The high-frequency heating device includes, for example, a half-open saddle type high-frequency heating coil 1, a current transformer 2 having the high-frequency heating coil 1 attached to the lower portion, and a current transformer 2.
Substantially above, a sprocket 40 having a horizontally fixed shaft 41, one end of which is wound around the sprocket 40, is located above the current transformer 2, and the other end is, for example, the frame 9 of a high-frequency heating device.
And a chain 30 fixed via a spring 80.

The operation of this high-frequency heating device will be described. Both ends of the crankshaft 100 are horizontally supported by an unillustrated appropriate chuck or center so that the crankshaft 100 is rotatable, and the crankshaft 100 is heated by, for example, a pin P1.
On the high frequency heating coil 1,
High frequency heating coil while rotating the crankshaft 100
Apply high frequency current to 1 for a specified time to heat pin P1.
Note that, for example, the pin P4 may be heated simultaneously with the pin P1 by using another high-frequency heating coil.

At this time, the pin P1 revolves around the shaft 101 of the crankshaft 100. That is, the pin P1 has its axis 102
Moves on a circle 103 centered on the axis 101 and rotates once during one revolution. Now, as shown in FIG. 3, the pin P1 comes directly above the journal J1 (top dead center) and just below the journal J1 (bottom dead center) (shown by a dotted line).

Since the high-frequency heating coil 1 follows the operation of the pin P1, it makes a vertical movement and a horizontal oscillation movement. Now, the total weight of the high frequency heating coil 1 and the current transformer 2 is W, the radius of the sprocket 40 is r, and the tension F of the spring 80 is F.
Then, the load M applied to the pin P1 from above is M × r = W × r−F × r. Therefore, when the pin P1 reaches the top dead center, F becomes the minimum and M becomes the maximum. Further, when the pin P1 reaches the bottom dead center, F becomes maximum and M becomes minimum. Then, as the pin P1 moves from top dead center to bottom dead center and from bottom dead center to top dead center, M decreases from the maximum to the minimum and then increases from the minimum to the maximum.

[0008]

The pin P1 after heating is cooled and the quenching is completed, but after quenching the other pins P2 to P4 and the journals J1 to J5 as well, the crankshaft 100
Is measured. It has been found that the magnitude of strain after quenching can be reduced by keeping the value of the load M applied to the pin during high frequency heating of the pin within a predetermined range. However, the conventional high-frequency heating method and apparatus for crankshafts cannot adjust the load applied to the pins within a predetermined range.

The present invention was devised in view of the above circumstances, and the load applied to the crankshaft pin during high frequency heating can be adjusted to a preset value.
An object of the present invention is to provide a high-frequency heating method and apparatus for a crankshaft, which can reduce distortion of the quenched crankshaft.

[0010]

In order to solve the above-mentioned problems, a method of high frequency heating of a crankshaft according to a first aspect of the present invention is characterized in that the crankshaft is supported horizontally and rotatably about the axis of the crankshaft. In a high-frequency heating method of a crankshaft, in which a high-frequency heating coil placed on a pin of the crankshaft is energized to heat the pin while rotating the crankshaft, a load applied to the pin during heating the pin can be adjusted.

In order to solve the above-mentioned problems, a high-frequency heating device for a crankshaft according to a second aspect of the present invention is mounted so as to straddle the pin of a horizontally arranged crankshaft to heat the pin. A high-frequency heating coil, a current transformer with the high-frequency heating coil attached to the bottom, a sprocket provided almost above the current transformer, one end fixed to the upper part of the current transformer, and the other end fixed to the sprocket by winding. And the first chain,
An eccentric cam arranged in parallel with the sprocket, a horizontal shaft connected to rotate the sprocket and the eccentric cam in an interlocking manner, and one end of the eccentric cam wound around the eccentric cam. And a second chain having the other end fixed to the high-frequency heating device via a spring, and the eccentric cam includes a second chain of the eccentric cam when the pin is at the top dead center. R is the distance between the contact starting point of the eccentric cam and the second chain of the eccentric cam when the pin is at the bottom dead center, and r2 is R> r2. And R
It is formed so that it changes gradually from r2 to r2.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high frequency heating apparatus for a crankshaft according to an embodiment capable of implementing the method of the present invention will be described below with reference to the drawings. The crankshaft is the same as the crankshaft 100 described in FIG. FIGS. 1 and 2 are explanatory views of the present embodiment, and FIGS. 1 and 2 show when the pin to be heated (in this embodiment, the pin P1 is picked up) reaches the top dead center and the bottom dead center, respectively. Indicates. The same components as those described in the related art are designated by the same reference numerals.

The high frequency heating apparatus of this embodiment comprises the same high frequency heating coil 1 and current transformer 2 as described with reference to FIG. Also, the sprocket 4 installed almost above the current transformer, one end fixed to the upper part of the current transformer 2, and the other end fixed to the sprocket 4
The chain 3 (first chain) wound around the sprocket 4 and fixed to one point 4a on the periphery of the sprocket 4 and the sprocket 4
An eccentric cam 6 arranged in parallel with the horizontal shaft 5 connected to rotate the sprocket 4 and the eccentric cam 6 in conjunction with each other.
Is wound around the eccentric cam 6, and one end of the eccentric cam is
A chain 7 fixed to one point 6c on the periphery of 6 and the other end fixed to, for example, a frame body 9 of a high-frequency heating device via a spring 8.
(Second chain).

The eccentric cam 6 is arranged so that when the pin P1 reaches the top dead center, the one point 6c to which the chain 7 is fixed is located right above the shaft 5 and on the side opposite to the spring 8. There is. Then, when the pin P1 is at the top dead center, the distance between the contact start point 6a of the eccentric cam 6 with the chain 7 and the shaft 5 is R, and
When the distance between the shaft 5 and the starting point 6b of contact with the chain 7 of the eccentric cam 6 when the pin P1 is at the bottom dead center is r2,
The eccentric cam 6 is formed so that R> r2, and also gradually and continuously changes from R to r2.

Next, the operation of this embodiment will be described.
Crankshaft 100, pin P1 and high frequency heating coil
1 is, while performing the exercise described in the prior art,
High frequency heating coil 1 heats pin P1. And FIG.
As shown in, the tension of the spring 8 when the pin P1 reaches the top dead center is F1, the load applied to the pin P1 is M1, and the sprocket 4 is
If the radius of is r1, then it is expressed as M1 * r1 = W * r1-F1 * R.

As shown in FIG. 2, when the tension of the spring 8 when the pin P1 reaches the bottom dead center is F2 and the load applied to the pin P1 is M2, M2 * r1 = W * r1-F2 * r2 Becomes F1 and F2 have a spring constant K (eg Kg / m
m)), the elongation L of the spring 8 at the top dead center and the bottom dead center of the pin P1 is determined.

Therefore, the spring constant K of the spring 8 and the eccentric cam 6
With proper selection of the distances R, r2 and the radius r1 of the sprocket 4, M1 and M2 can be in the desired predetermined range, ie about 5-10 kg. In addition, the distortion of the crankshaft hardened by using the high frequency heating device in which the load applied to the pin of the crankshaft is adjusted to a desired range as described above, the distortion of the crankshaft is TIR (Total Indicator Read
ing) was 0.07 to 0.3 mm, which was a significant improvement from the value of 0.18 to 1.2 mm obtained by the conventional high-frequency heating device.

[0018]

As described above, in the high frequency heating method for the crankshaft according to the first aspect, the crankshaft is supported horizontally and rotatably about the axis of the crankshaft, and then the crankshaft is rotated. While
In a high-frequency heating method for a crankshaft, which energizes a high-frequency heating coil mounted on a pin of a crankshaft to heat the pin, the load applied to the pin during heating the pin can be adjusted.

A high frequency heating apparatus for a crankshaft according to a second aspect of the present invention includes a high frequency heating coil which is placed so as to straddle a pin of a horizontally arranged crankshaft and heats the pin, and the high frequency heating coil. A current transformer having a coil attached to a lower portion thereof, a sprocket provided substantially above the current transformer, a first chain having one end fixed to an upper portion of the current transformer and the other end wound and fixed to the sprocket, An eccentric cam arranged in parallel with the sprocket, a horizontal shaft connected to rotate the sprocket and the eccentric cam in an interlocking manner, and one end wound around the eccentric cam around the eccentric cam. A second chain that is fixed and has the other end fixed to the high-frequency heating device via a spring, and the pin of the eccentric cam is at the top dead center The distance between the starting point of contact of the eccentric cam with the second chain and the shaft is R, and the distance between the starting point of contact of the eccentric cam with the second chain and the shaft when the pin is at the bottom dead center. When r2 is r2, it is formed so that R> r2, and moreover, it gradually and continuously changes from R to r2.

Accordingly, in the method and apparatus for high frequency heating of the crankshaft of the present invention, the load applied to the pin to be heated can be adjusted in advance so as to fall within a desired range. It is possible to reduce the distortion of the crankshaft hardened by using it.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a high-frequency heating device capable of realizing a high-frequency heating method for a crankshaft according to the present invention, showing when a pin reaches a top dead center.

FIG. 2 is an explanatory view of an embodiment of a high-frequency heating device capable of realizing the high-frequency heating method for a crankshaft of the present invention, showing when the pin reaches the bottom dead center.

FIG. 3 is an explanatory diagram of a high-frequency heating device for performing a conventional high-frequency heating method for a crankshaft. It is explanatory drawing of the conventional high frequency heating device of a crankshaft.

FIG. 4 is a front explanatory view of a crankshaft.

[Explanation of symbols]

 1 High frequency heating coil 2 Current transformer 3 Chain 4 Sprocket 5 Axis 6 Eccentric cam 6a, 6b Contact start point 7 Chain 8 Spring 9 Frame 100 Crankshaft P1 to P4 Pin R, r2 Distance r1 Radius

Claims (2)

[Claims] 1. A crankshaft is supported horizontally and rotatably about an axis of the crankshaft, and then while rotating the crankshaft, a high-frequency heating coil mounted on a pin of the crankshaft is energized to fix the pin. A high-frequency heating method for a crankshaft, comprising heating a pin and adjusting a load applied to the pin during heating. 2. A high frequency heating coil which is placed so as to straddle a horizontally arranged crankshaft pin to heat the pin, a current transformer having the high frequency heating coil attached to a lower portion thereof, and the current transformer. Of the sprocket, a first chain having one end fixed to an upper portion of the current transformer and the other end wound around and fixed to the sprocket, an eccentric cam arranged in parallel with the sprocket, The horizontal shaft connected to rotate the sprocket and the eccentric cam in an interlocking manner, and the high-frequency heating device that is wound around the eccentric cam and has one end fixed around the eccentric cam and the other end via a spring. A second chain fixed to the eccentric cam, and the eccentric cam has a starting point of contact with the second chain of the eccentric cam when the pin is at the top dead center and the shaft. And R is R, and R2 is the distance between the shaft and the starting point of contact with the second chain of the eccentric cam when the pin is at the bottom dead center, R> r2, and , R to r2 are formed so as to be gradually and continuously changed.