Electricity: circuit makers and breakers – Solid contact – Rotating actuator
Reexamination Certificate
1999-10-25
2001-01-16
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Solid contact
Rotating actuator
C200S564000, C200S0110TC
Reexamination Certificate
active
06175091
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a rotary type electronic component which generates a given signal by rotating a rotary shaft, and it also relates to a method of manufacturing the same component.
BACKGROUND OF THE INVENTION
In recent years, electronic devices have been down sized and yet equipped with more functions, which demands the electronic components employed in those devices to be smaller in size. Torque of a rotary-type-electronic-component, in general, decreases at the smaller size of the component while the structure thereof is maintained. This drawback has been overcome, and downsized rotary type electronic components with given torque are prevailing in the market.
A rotary type encoder, as an example of the conventional rotary type electronic component, is described hereinafter with reference to
FIGS. 4 and 5
.
FIG. 4
is a side sectional view of a conventional high-torque rotary encoder, and
FIG. 5
is an exploded perspective view of the same.
In
FIGS. 4 and 5
, rotary shaft
510
is made of resin, and its upper section works as an operating section
511
. A lower section of shaft
510
has flange
512
formed integratively therewith. A mid section of shaft
510
forms cylindrical shaft
513
journaled by through-hole
521
boring in metal bearing
520
. Grease of high viscosity is applied to the journaling section.
Beneath bearing
520
, flange
512
and box-type case
530
made of resin are situated in tandem. Beneath the center of flange
512
, positioning section
514
is provided, which is inserted into hole
531
provided on case
530
so that shaft
510
is jounraled by case
530
.
Beneath flange
512
, movable contact
540
made of resilient metal leaf is mounted. Movable contact
540
elastically contact to fixed contact
550
formed by contacts forming in radial on recessed base of case
530
. Both the contacts form a contact section for producing pulse signals. Terminal
560
electrically conductive to fixed contact
550
extends outside case
530
from a side of case
530
. Contact
540
,
550
and terminal
560
form electric-signal-producing-section
570
.
Metal cover
580
covers periphery of the base of bearing
520
and locks case
530
. Between cover
580
and an upper face of case
530
, a frame of spring
590
made of resilient metal leaf is rested. Resilient leg section
591
of spring
590
elastically contacts on step
515
of flange
512
.
An operation of the rotary encoder constructed above is described as follows:
When operating section
511
of shaft
510
is rotated, flange
512
rotates accordingly. Then movable contact
540
elastically slides on fixed contact
550
, thereby producing a pulse signal as a given electric signal. The pulse signal is taken out from a plurality of terminals
560
.
Resilient leg
591
of spring
590
urges downwardly step
515
of flange
512
so that step
515
rotates. Shaft
510
thus obtains predetermined torque.
As discussed above, the conventional encoder is constructed such that shaft
510
can obtain high torque by urging elastically leg section
591
against step
515
.
However, according to this construction, the outer diameter of leg section
591
of spring
590
is obliged to decrease at the narrower diameter of the electronic component, which weakens the urging force of leg section
591
. In order to overcome this drawback, it is a general method that the elastic urging force of spring
590
is boosted considering the material and leaf thickness of spring
590
. This method still has some limit, and if a greater urging-force of the spring can be produced, it would apply an intensive pressure to a local point on flange
512
where spring
590
urges. Even if grease is applied to the contact face, tactile feel at operating becomes worse, and the frictional faces are heavily worn out.
SUMMARY OF THE INVENTION
The present invention addresses the problems discussed above, and aims to provide a down-sized rotary type electronic component which still keeps required high and stable torque with smooth tactile feel as well as a long service-life. The present invention also aims to provide a manufacturing method of this component.
A rotary type electronic component of the present invention comprises the following elements:
(a) a bearing comprising: a cylinder section; and a substrate on which the cylinder section is rested,
(b) a rotary shaft comprising:
an upper section protruding from the bearing;
a mid section journaled by the bearing; and
a lower section comprising:
a flange formed around the lower section;
a hole punched through the flange; and
a movable contact disposed on a lower face of the flange,
a recess axially provided in the rotary shaft and communicating with the hole through the flange;
(c) a case coupling to a lower face of the substrate of the bearing so that the case covers the lower section of the rotary shaft, and on a bottom plate thereof having a fixed contact corresponding to the movable contact;
(d) a spring housed by the recess of the rotary shaft, and urging the bottom plate of the case from an inner part of the recess;
(e) a frictional plate having a hole bored therethrough axially, engaging with an inlet rim of the recess prepared in the rotary shaft, being urged by the spring force against the bottom plate of the case, and rotating together with the rotary shaft; however, being axially movable independently of the rotary shaft.
This construction allows the flange of the shaft to contact with the substrate of the bearing in a wider area, which produces the greater friction. As a result, this downsized rotary type electronic component still keeps required high torque and smooth tactile feel as well as a long service-life.
A manufacturing method of the rotary type electronic component of the present invention comprises the following steps, where the component described above further includes a pole standing on the bottom of the recess provided in the rotary shaft. The pole extends through the spring and is press-fitted into the hole bored in the frictional plate with such a strength that the plate can move axially by a force not less than a biasing force of the spring, and yet weights of the spring and frictional plate are insufficient for themselves to come off from the pole. The manufacturing method comprises the steps of:
extending the pole through the hole bored in the frictional plate;
compressing the spring; and
widening an end of the pole to form a stopper preventing the spring and the frictional plate from coming off from the pole so that the rotary shaft, spring and frictional plate are integrated.
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patent: 4439654 (1984-03-01), Bresin et al.
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patent: 5310974 (1994-05-01), Churchill et al.
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patent: 6049044 (2000-04-01), Mizobuchi
Fukuda Tetsuya
Matsui Hiroshi
Nishimura Takahiro
Friedhofer Michael
Matsushita Electric - Industrial Co., Ltd.
Ratner & Prestia
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