Electric heating – Inductive heating – Specific heating application
Reexamination Certificate
2000-11-17
2002-06-18
Walberg, Teresa (Department: 3742)
Electric heating
Inductive heating
Specific heating application
C074S570200, C148S572000
Reexamination Certificate
active
06407372
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an eccentric driving apparatus for causing a certain object to revolutionarily move without being associated with auto-rotational movement, and more specifically to an eccentric driving apparatus suitable for use in hardening equipment for cam shaft which carries out simultaneous hardening of the outer peripheral surface of each cam of a cam shaft having plural kinds of cams of different phases formed thereon.
2. Prior Art
A cam shaft used in an engine for an automobile has plural kinds of cams having different phases, and induction hardening is carried out on the outer peripheral surface of each cam. For achieving this induction hardening, a heating device equipped with a plurality of heating coils of circular shape which correspond to the respective cams is utilized. That is, a cam shaft is rotated in the state that a cam shaft is passed through the plurality of heating coils which are arranged in the direction of central line and the corresponding cams are positioned inside the respective heating coils, and whereby induction heating of the outer peripheral surface of each cam is effected simultaneously.
In conventional hardening equipment for a cam shaft, the plurality of heating coils are concentrically arranged, so that the center of the cam shaft corresponds to the center of the coils. Therefore, in the hardening of each cam, as shown in
FIG. 6
, the outer peripheral surface of each cam
11
of a cam shaft
10
is heated while being rotated inside a heating coil
21
in the state that the center O
1
thereof corresponds to the center O
2
of the heating coil
21
, and subsequently cooled to complete hardening.
In such a way of hardening, however, a convex portion of the cam
11
always moves in the vicinity of the inner surface of the heating coil
21
, which causes an essential disadvantage that the portion in question is hardened in larger depth than other portions.
For eliminating this disadvantage, the applicant of the present invention has developed such hardening technique that, as shown in
FIG. 7
, the center O
2
of the heating coil
21
is made to be eccentric away from the center O
1
of the cam
11
toward the convex side, and the heating coil
21
is revolved about the center O
1
of the cam
11
in accordance with the rotation of cam
11
, thereby hardening the outer peripheral surface of the cam
11
with a substantially uniform depth over the entire circumference (See Japanese Patent Application No. 11-319879 (1999) and Japanese Patent Application 2000-020417). As the hardening equipment for realizing the above technique, those shown in
FIG. 8
or
9
have been suggested.
In the hardening equipment shown in
FIG. 8
, a plurality of heating devices
20
,
20
corresponding to cam phases of the cam shaft
10
are provided. The plurality of heating devices
20
,
20
are arranged on both sides of a hardening position of the cam shaft
10
, respectively. Each heating device
20
has the heating coil
21
of circular shape which fits with the outside of the corresponding cam
11
of the cam shaft
10
and a transformer
22
for supplying the heating coil
21
with electric power, and the heating coils
21
,
21
are made to be eccentric from the center O
1
of the corresponding cams
11
,
11
toward the convex side by a certain amount.
Each heating device
20
is revolved by an eccentric driving apparatus
30
. The eccentric driving apparatus
30
has a support
31
for supporting the transformer
22
, a bearing
32
attached on the bottom surface of the support
31
, an eccentric cam
33
to be fitted with the bearing
32
and a rotation driving shaft
34
for driving the eccentric cam
33
.
In the eccentric driving apparatuses
30
,
30
disposed on both sides, the rotation driving shafts
34
,
34
are driven by a common driving source
40
. The eccentric cams
33
,
33
are deflected in their rotation phases in accordance with the phase difference between the corresponding cams
11
,
11
of the cam shaft
10
.
In the hardening, the driving source
40
is actuated in accordance with the rotation of the shaft
10
to rotate the driving shafts
34
,
34
. In response to this, the heating devices
20
,
20
revolve at a certain phase difference without auto-rotating. As a result, the heating coils
21
,
21
revolve about the center O
1
of the corresponding cams
11
,
11
without being associated with auto-rotation.
To the contrary, in the hardening equipment shown in
FIG. 9
, the heating devices
20
,
20
are driven by the eccentric driving apparatus
30
,
30
of the biaxial driving system. That is, the eccentric driving apparatus
30
has two driving sources
35
,
36
for linearly driving the heating device
20
in two directions perpendicular to the center line of the cam shaft
10
, and the heating device
20
is caused to revolve by operation control of the driving sources
35
,
36
.
Comparing the hardening equipment shown in FIG.
8
and the hardening equipment shown in
FIG. 9
, the heating devices
20
,
20
are the same between these equipments. However, the eccentric driving apparatuses
30
,
30
are significantly different between these equipments. That is, in the hardening equipment shown in
FIG. 8
, the eccentric driving apparatuses
30
,
30
are driven by the common driving source
40
, while in the hardening equipment shown in
FIG. 9
, the eccentric driving apparatuses
30
,
30
each need the two driving sources
35
,
36
, individually. Therefore, the former hardening equipment shown in
FIG. 8
is much simpler in structure so that the cost thereof is low.
The eccentric driving apparatuses
30
,
30
shown in
FIG. 8
, however, have a significant problem in the hardening operation as follows.
More specifically, in the case of carrying out hardening on the cam shaft
10
, the cam shaft
10
is positioned at the hardening position while being passed through the heating coils
21
,
21
aligned in the axial direction. In the eccentric driving apparatuses
30
,
30
of the hardening equipment shown in
FIG. 8
, the amount of eccentricity is uniquely determined by the eccentric cams
33
,
33
and hence the adjustment thereof is impossible, with the result that the heating coils
21
,
21
are made to be eccentric fixedly in different directions in accordance with the phases of the cams
11
,
11
of the cam shaft
10
.
For this reason, it is impossible to effect the operation of zero recover for bringing the respective centers of the heating coils
21
,
21
into correspondence with the respective centers O
1
of the cams
11
,
11
, so that it is impossible to concentrically align the heating coils
21
,
21
. As a result, the positioning operation of the cam shaft
10
at the time of hardening operation becomes difficult and even becomes impossible when the amount of eccentricity of the heating coils
21
,
21
is large. Furthermore, the amount of eccentricity of the heating coils
21
,
21
is restricted to cause some troubles for uniform hardening of the respective outer peripheral surfaces of the cams
11
,
11
.
Incidentally, in the eccentric driving apparatuses
30
,
30
of the hardening equipment shown in
FIG. 9
, the heating coils
21
,
21
are easily recovered to the zero positions and concentrically aligned by controlling the driving sources
35
,
36
.
The present invention has made in consideration of the above problems, and an object of the present invention is to provide an eccentric driving apparatus having a simple structure and enabling arbitrary and simple adjustment of the amount of eccentricity.
SUMMARY OF THE INVENTION
An eccentric driving apparatus according to the present invention is an eccentric driving apparatus for revolving a certain object without being associated with auto-rotation, the eccentric driving apparatus comprising: a bearing for supporting the object, the bearing being supported so as to be movable in two directions perpendicular to the center of the revolution; a first rotation sleeve rotatably fitted
Fuji Electronics Industry Co., Ltd.
Kilyk & Bowersox P.L.L.C.
Van Quang T
Walberg Teresa
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