Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-03-18
2001-09-11
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S081000, C029S598000
Reexamination Certificate
active
06288459
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vibration generating device adapted to be built in a game controller or the like for vibrating the controller itself or for alerting signal reception in a portable cellular telephone or a pager unit, and a method for mounting a weight to the vibration generating device.
2. Description of Related Art
FIG. 8
is a front view for explaining a method of mounting a weight to a motor shaft in a conventional vibration generating device, showing the state of the weight before mounting.
FIG. 9
is a front view showing the state of the weight after mounting.
The conventional weight
10
stated above has a body
11
of a semicircular columnar section, and is provided with a U-groove
4
formed at the center in the diametral direction of the body
11
, for the insertion of a motor shaft
3
. On both sides of the U-groove
4
projections
13
a
and
13
b
are formed upwardly.
When the aforesaid weight
10
is mounted on the shaft
3
, the shaft
3
is inserted first into the U-groove
4
of the weight
10
and supported in position. Next, a support block
1
is used to support the weight
10
thereon. The supporting surface of the support block
1
has the same configuration as the perimeter (curved portion) of the weight
10
, so that the perimeter of the weight
10
will be fitted in the curved portion
1
a
of the support block
1
, with the flat portion of the weight
10
held level.
Subsequently a pressing member
12
with a recess portion
12
a
of a triangular section is lowered from above the weight
10
until the weight
10
is fastened on the shaft
3
. That is, the surface area of the recess portion
12
a
formed in the forward end of the pressing member
12
is formed smaller than the surface area formed by the projections
13
a
and
13
b
and by a space between the projections
13
a
and
13
b
. Therefore the recess portion
12
a
of the pressing member
12
is fed downwardly into contact with the tips of the projections
13
a
and
13
b
and is further pressed downwardly to bend both projections
13
a
and
13
b
inwardly (in the directions of the arrows R and L), thereby caulking the weight
10
to the shaft
3
.
However, the conventional weight
10
and the method of mounting the same as shown in
FIGS. 8 and 9
have the problem that the vibration generating device is suitable for use where the weight
10
is produced of a relatively soft material such as copper. In the case of the weight
10
produced of a relatively hard material such as iron, a great load is required when the weight
10
is mounted to the shaft
3
.
If a small load is applied when mounting the weight
10
to the shaft
3
, the weight
10
mounted by a conventional method can easily be removed from the shaft
3
with a relatively little force; it is likely, therefore, that when a motor using the weight
10
is in practical use, the weight
10
will move out of position on the shaft
3
during rotation (during use), producing a noise or coming off from the shaft to impair the device itself.
In the weight
10
having the U-groove
4
shown in
FIGS. 8 and 9
, the inside wall surface of the U-groove
4
is formed straight, and therefore it is necessary to largely deform the straight inside wall surface into a curved surface along the perimeter of the shaft
3
by applying a pressure by the pressing member
12
, that is, by applying a great load to the projections
13
a
and
13
b
. Therefore the projections
13
a
and
13
b
, if applied with a little load, will be insufficiently deformed, resulting in a small contact surface area between the inside wall surface of the U-groove
4
and the curved surface of the shaft
3
. Consequently the mounting pressure will decrease and the weight
10
will come off the shaft
3
if a weight mounted is a large type and accordingly an increased load is applied to the weight.
SUMMARY OF THE INVENTION
An object, therefore, of the present invention is to provide a vibration generating device in which a weight produced of a hard material such as iron requires little pressure of the pressing member to caulk the weight, and will not accidentally move off position during use, and also to provide a method of mounting the weight to the vibration generating device.
The vibration generating device of the present invention is a vibration generating device mounted with a vibration generating weight on a motor shaft. In the vibration generating device, the weight is provided with a shaft insertion hole of an approximately semicircular section which is partly open at the center in a radial direction, and a recess portion for caulking located in the vicinity of the open portion of the insertion hole. With the shaft inserted in the insertion hole, a pressure is applied to the recess formed on the weight or the open end side of the recess, thereby securely fastening the shaft in the insertion hole.
By the above-described method, the weight can be firmly attached to the shaft with a pressure less than that in the conventional method even if the weight is produced of a hard material such as iron. Furthermore cost reduction is realized because the weight can be produced of a low-cost material such as iron. Furthermore, since iron is easily workable to a desired accuracy and less liable to deformation, the weight is hard to accidentally come off the shaft.
In the case stated above, the inside wall surface of the insertion hole enclosing the shaft is desired to be formed larger in angle than 180 degrees.
The weight thus formed, when pressed to deform, can be held in surface contact with the shaft. That is, the inside wall surface of the insertion hole, being formed as an approximately same curved surface as the shaft, makes a surface contact with the curved surface of the shaft when pressed to deform. Therefore, as compared with the conventional weight having the U-groove, the weight of the present invention can be mounted much more firmly on the motor shaft.
It is desirable that a clearance between the inside wall surface of the insertion hole and the shaft be {fraction (1/100)} mm or more and {fraction (8/100)} mm or less, and more desirable that the clearance be {fraction (3/100)} mm or more and {fraction (5/100)} mm or less.
The weight formed as described above, when pressed, is able to be firmly and reliably fastened on the shaft. If the clearance, however, is under {fraction (1/100)} mm, it is impossible to provide a working accuracy, resulting in difficult shaft insertion into the insertion hole of the weight. Conversely if the clearance exceeds {fraction (8/100)} mm, the contact surface area between the inside wall surface of the insertion hole and the shaft becomes small at the time of pressure application, with the result that the weight can not firmly be mounted on the shaft.
It is also desirable that a thickness between the recess and the inside wall surface of the insertion hole be formed over 0.5 time and under 1.0 time in relation to the shaft diameter.
The weight can be firmly fastened to the shaft by adopting the above-described desirable range of settings. When the thickness stated above is not less than 1.0 time the shaft diameter, the inside wall surface of the shaft insertion hole becomes hard to deform when the weight is pressed, and therefore the countershaft can not be fastened to the shaft. In case the thickness is under 0.5 time also, the weight-to-shaft holding pressure will decrease.
The method of mounting the weight to the vibration generating device of the present invention includes a process to insert the motor weight to the shaft, a process to hold the weight, and a process to apply a pressure to fasten the weight to the shaft. In the weight mounting method, a weight is of an approximately semicircular columnar section and has a shaft insertion hole partly open at center in the diametral direction and a recess in the vicinity of the open portion of the insertion hole. After the insertion of the shaft into the insertion hole of the weight, the weight is supported in such a m
Furudate Toshio
Hosobuchi Shinichi
Inada Yuji
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Tamai Karl
LandOfFree
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