JPH0143396Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a crankshaft rotation mechanism for an induction hardening device.

Prior Art FIG. 3 shows a front view of a conventional crankshaft induction hardening machine. A bracket 3 formed in a substantially L shape is attached to a shaft 2 provided perpendicularly to the upper surface of the base plate 1.
is attached to the shaft 2 so as to be movable up and down in the longitudinal direction. A current transformer 5 and a work coil 6 fixed to the current transformer 5 are suspended near the tip of the horizontal portion of the bracket 3 via a pantograph 4.

A pin portion 11 of a crankshaft (not shown) is in contact with the lower surface of the work coil 6 (1
1 shows the cross section of the pin part). Reference numeral 15 indicates the center point of the cross section of a journal portion (not shown) of the crankshaft.

Now, when the crankshaft is rotated in the direction of arrow A around the center point 15, the center point 12 of the pin part 11 moves on the circle 13, the pin part 11 revolves, and the pin part 11 rotates for one revolution. It rotates once. That is, the pin portion 11 first descends and then rises in the vertical direction. At this time, the work coil 6, current transformer 5, and bracket 3 are lowered by their own weight, and the work coil 6 is lowered by the pin portion 11.
It descends while remaining in contact with. Further, when the pin portion 11 rises, the pin portion 11 pushes up the bracket 3 via the work coil 6, current transformer 5, and pantograph 4.

When performing surface hardening with deviation on the pin part 11, a small current is applied to the work coil 6 for 1/3 of the period during which the pin part 11 makes one revolution, and a large current is applied to the work coil 6 for 2/3 of the period. It is necessary to turn on electricity. That is, pin part 1
During the first revolution of 1, when the center point 12 comes to point P which is -60 degrees before the highest point, switch from high current to small current, and then at a position of 60 degrees after the highest point. When a certain Q point is reached, the current is switched from small to large. When the center point 12 comes to point P again, the large current is switched to the small current. The above cycle is repeated for a predetermined period of time. Incidentally, deviation induction surface hardening is, as mentioned above, in which the magnitude of the current flowing through the induction hardening coil is changed according to the rotation angle of the crankshaft while the crankshaft is rotating. This refers to hardening that forms hardened layers of different depths on the circumferential surface of the journal or journal part, and usually for the pin part, energization is applied to the surface of the pin part that is far away from the journal part, as described above. The current is reduced to reduce the thickness of the cured layer in this portion, and the current applied to the portion near the journal portion is increased to increase the thickness of the cured layer in this portion.

Incidentally, point R is the lowest point of the center point 12, and when the center point 12 reaches this point R after starting to drive the crankshaft, energization of the work coil 6 with a large current is started. Then the center point 12 is P
When reaching point and point Q, the current applied to the work coil 6 is switched as described above.

7a, 8a, 9a are cams fixed to the side surfaces of the bracket 3, and levers 7b, 8b, 9, respectively.
The limit switches 7c, 8c, 9c having the number b correspond to the cams 7a, 8a, 9a.

After starting to drive the crankshaft, center point 1
2 reaches the R point, the cam 9a hits the lever 9b, the limit switch 9c is activated, and a signal is issued to start energizing the work coil 6. When this energization is started, the above-mentioned large current is applied to the work coil 6.

Next, when the center point 12 of the pin part 11 comes to point P, the cam 8a hits the lever 8b from below to the top, and the limit switch 8c is activated, which sends a signal to switch the current flowing through the work coil 6 from a large current to a small current. emits. When the center point 12 comes to the Q point, the cam 7
A hits the lever 7b from above to below, activating the limit switch 7c and issuing a signal for switching the small current flowing through the work coil 6 to a large current.

When the center point 12 comes to point P again, the limit switch 8c issues a signal for switching the current flowing to the work coil 6 from a large current to a small current.

Repeat the above cycle. Note that the signal to end the energization of the work coil 6 is sent by a timer (not shown) at a preset time after the start of energization.

The limit switch 7c is configured not to emit a signal when the cam 7a hits from below to above, and the limit switch 8c does not issue a signal when the cam 8a hits from above to below.

Problems to be Solved by the Invention In the above, when the center point 12 reaches the P point, the Q point, and the R point, the limit switches 7c and 8 are activated, respectively.
It is generally difficult to operate c and 9c accurately. That is, there is no proportional relationship between the rotation angle accompanying the revolution of the center point 12 and the moving distance of the cams 7a, 8a, or 9a. That is, even when the rotation angle accompanying the revolution is large, the moving distance of the cam is Therefore, it is difficult to set accurate positions of cams 7a, 8a and 9a corresponding to points P, Q and R, respectively, and limit switches 7c, 8c and 9c are 7b, 8
There is an inherent play between the movement of b and 9b and the operation of the limit switch, which is different for each limit switch.For these reasons, it is necessary to readjust the limit switch every time the crankshaft is different, which is very time consuming. It is taking place.

The present invention has been developed in view of the above circumstances, and is intended to provide a crankshaft rotation mechanism in which the switching point of the current flowing through the work coil 6 can be easily set.

Means for solving the problem: While the crankshaft is rotating, the magnitude of the current applied to the induction hardening coil is changed according to the rotation angle of the crankshaft, and the depth is applied to the circumferential surface of the pin or journal part of the crankshaft. In a crankshaft rotation mechanism of an induction hardening device used when performing deviation induction hardening to form hardened layers of different types, a cam rotatably attached to a shaft that drives the crankshaft, and The gist of the configuration is to include a limit switch that operates to issue a signal that changes the magnitude of the applied current, and a scale plate attached to the shaft for adjusting the position of the cam.

Action When the shaft that drives the crankshaft is rotated,
When the pin part rotates 60 degrees from the highest position, the cam comes to the center point of the limit switch, and the limit switch issues a signal to switch the work coil current from a small current to a large current, and the pin part rotates further 240 degrees. When the cam rotates once, the other cam comes to the center point of the other limit switch, and the other limit switch issues a signal to switch the current flowing through the work coil from a large current to a small current.

Embodiment FIG. 1 shows a partially cutaway front view of an embodiment of the present invention. Further, FIG. 2 shows a side view seen from the direction of arrow B--B in FIG. 1.

Reference numeral 10 designates a crankshaft for a four-cylinder internal combustion engine, which has pin portions 11a, 11b, 11c and 11d and journal portions 16a, 16b, 16c, 16d and 16e to be induction hardened. The right end of the crankshaft 10 is supported by a support stand (not shown), and the left end is supported by a center pin 21, which will be described later.

The center pin 21 is formed protruding from the center of a flange surface 24a of a flange 24 formed at one end of a shaft 25 that drives the crankshaft 10.
Further, a substantially L-shaped crankshaft positioning member 23 is formed protruding near the outer periphery of the flange surface 24a, and a protrusion 22 is formed protruding near the tip of this crankshaft positioning member 23. A hole 14b is bored near the outer periphery of the flange surface 14a of the flange 14 formed at the left end of the crankshaft 10, and the protrusion 22 is inserted into this hole 14b.

A motor 27 for driving the shaft 25 is coupled to the shaft 25 via a reduction gear 26 .

Additionally, three cam assemblies 30 are mounted on the shaft 25.
a, 30b and 30c, and two scale plates 37a
and 37b are fixed.

The cam assembly 30a includes a substantially fan-shaped cam 31a formed on the outer circumferential surface of a cylindrical portion 32a fitted onto the shaft 25, and a cam 31a protruding from the outer circumferential surface of the cylindrical portion 32a at a position opposite to the cam 31a. two legs 33a each having a rectangular cross section;
A screw 35a is attached to a screw hole 34a formed in a. Note that the cylindrical portion 32
A is provided with a cutout 36a between the two legs 33a. Therefore, the cam assembly 30a can be fixed to the shaft 25 by tightening the screw 35a, and the cam 31 can be fixed by loosening the screw 35a, changing the position of the cam 31a, and tightening it again.
The setting position of a can be changed. Cam assembly 3
The same applies to 0b and 30c.

The scale plates 37a and 37b each have a key 38
It is fixed to the shaft 25 by a and 38b.

The aforementioned cam assemblies 30a, 30b and 3
Contactless limit switch 40 corresponding to 0c
a, 40b and 40c are mounted on a limit switch mounting base 41.

Cam 31a, limit switch 40a, cam 3
1b, limit switch 40b and cam 31c
and limit switch 40c, the center point of the cross section of pin portion 11b (point corresponding to 12 in FIG. 3, hereinafter referred to as center point 12b) is point P in FIG. 3, and limit switch 40c, respectively.
This is to detect when the Q point and the R point have been reached. The set positions of the cams 31a, 31b, and 31c are set at a relative angle of 120 degrees to each other. In addition, limit switches 40a, 40b,
40c are all mounted at the same height on a line parallel to the axial direction of the shaft 25.

Next, in this embodiment, the crankshaft 1
The operation will be described in the case where the pin portion 11b of No. 0 is induction hardened.

The motor 27 is activated to rotate the shaft 25, ie, the crankshaft 10, in the direction of arrow A in FIGS. 2 and 3.

When the center point 12b comes to point R in Fig. 3, the cam 3
The tip 31c1 of 1c is the limit switch 40c
When the limit switch 40c reaches the center of the work coil 6, the limit switch 40c issues a signal to start energizing the work coil 6 shown in FIG. In this case, a large current flows through the work coil 6.

When the center point 12b reaches the P point position in FIG.
0a, the limit switch 40a issues a signal for switching the current to the work coil 6 shown in FIG. 3 from a large current to a small current. cam 3
Even if 1a passes the limit switch 40a,
A mechanism (not shown) that controls the current flowing through the work coil 6 maintains a small current flowing through the work coil 6.

When the center point 12b reaches the position of the Q point, the cam 3
The tip 31b1 of 1b is the limit switch 40b
When the limit switch 40b reaches the center of the work coil 6, it issues a signal for switching the current flowing to the work coil 6 from a small current to a large current. Even if the cam 31b passes the limit switch 40b, the current flowing through the work coil 6 is maintained at a large current by the mechanism for controlling the current flowing through the work coil 6.

Next, when the tip 31a1 of the cam 31a comes to the center of the limit switch 40a again, the limit switch 40a issues a signal to switch the current flowing to the work coil 6 from the large current to the small current again. The above steps are then repeated for a predetermined period of time. Note that the signal to end the energization to the work coil 6 is sent by a timer (not shown) at a preset time after the start of energization.

Note that the positions of the cams 30a, 30b, and 30c can be easily adjusted since scale plates 32a and 32b are provided.

Note that the support stand for the shaft 25 is not shown.

Effects of the invention As explained above, conventionally, the revolution angle of the center point of the pin portion of the crankshaft is indirectly detected by the vertical movement distance of the center point, and the current applied to the work coil is switched. However, according to the present invention, the revolution angle is directly detected by a cam attached to the drive shaft of the crankshaft and a corresponding limit switch to switch the current flowing to the work coil. The switching point can be easily set.

[Brief explanation of the drawing]

FIG. 1 shows a partially cutaway front view of an embodiment of the present invention. Further, FIG. 2 shows a side view seen from the direction of arrow B--B in FIG. 1. FIG. 3 is a front view of a conventional crankshaft induction hardening machine. 2... Axis, 3... Bracket, 4... Pantograph, 5... Current transformer, 6... Work coil, 7a, 8a, 8a... Cam, 7b, 8b,
9b... Lever, 7c, 8c, 9c... Limit switch, 11, 11a, 11b, 11c, 11d
... Pin part, 12, 12b, 15 ... Center point, 1
3... Circle, 16a, 16b, 16c, 16d, 1
6e...Journal part, 25...Shaft, 30a, 3
0b, 30c...Cam assembly, 31a, 31
b, 31c...cam, 31a1, 31b1, 31
c1...Tip, 40a, 40b, 40c...Limit switch.

Claims (1)

[Scope of utility model registration request] A deviation method in which hardened layers of different depths are formed on the circumferential surface of the pin or journal portion of the crankshaft by changing the magnitude of the current applied to the induction hardened coil according to the rotation angle of the crankshaft while rotating the crankshaft. In a crankshaft rotation mechanism of an induction hardening device used when performing induction surface hardening, a cam is rotatably attached to a shaft that drives the crankshaft, and the cam operates to control the energizing current. 1. A crankshaft rotation mechanism for an induction hardening apparatus, comprising: a limit switch that emits a signal that changes the magnitude of the cam; and a scale plate attached to the shaft for adjusting the position of the cam.