192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
2000-03-31
2001-08-21
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
Reexamination Certificate
active
06276506
ABSTRACT:
This application is based on patent application Nos. 11-96943 and 11-288315 filed in Japan, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic clutch in which a shaft rotatable about an axis thereof is electrically connected to an input-side rotary member such as a gear, which is rotatably mounted onto the shaft.
Generally, an electromagnetic clutch of the above type is used as a part operatively connected to a sheet feed mechanism of an image forming apparatus such as a copier. As an example, the electromagnetic clutch includes a shaft rotatable about an axis thereof, an input-side rotary member (a gear), an output-side rotary member (rotor), a drive transmitting member (an armature) which is provided between the gear and the rotor and rotatable together with the gear. When the armature is magnetically attracted to the rotor against an urging force of a plate spring or the like due to a magnetic flux generated by an electromagnetic induction generating section, the rotation of the gear is transmitted to the shaft.
The electromagnetic clutch having the above construction is, for example, shown in the cross-sectional diagram of FIG.
18
. In
FIG. 18
, numeral
51
is a rotor,
52
is a center through hole of the rotor
51
,
53
is a shaft,
54
is a knurled threaded portion formed on the outer circumference of the shaft
53
. The electromagnetic clutch is assembled in such a manner that the shaft
53
is pressfitted into the through hole
52
of the rotor
51
with the knurled threaded portion
54
of the shaft
53
pressing the rotor
51
at a portion corresponding to the through hole
52
. Alternatively, the rotor
51
is loosely mounted onto the shaft
53
and then fastened thereon by swaging the rotor
51
at a part corresponding to the through hole
52
.
In the above-constructed electromagnetic clutch, press-fitting or swaging is necessary when mounting the rotor
51
onto the shaft
53
, which makes an assembling operation of the electromagnetic clutch complex.
Also, when mounting the rotor
51
onto the shaft
53
, an unnecessary external force may be exerted on the rotor
51
, and an undesirable mechanical stress may be generated on a surface of the rotor
51
toward which an armature is electromagnetically attracted. As a result, a magnetic attraction force on the surface of the rotor
51
may vary. In view of the above drawback, it is necessary to mount the rotor
51
onto the shaft
53
with an utmost care, which may further make the assembling operation cumbersome.
SUMMARY OF THE INVENTION
In view of the above, an object of the present invention is to provide an electromagnetic clutch having a structure that enables to simplify the assembling operation of the electromagnetic clutch.
According to an aspect of this invention, an electromagnetic clutch comprises: a rotatable shaft; a field coil having an energizing coil mounted on the shaft; an output-side rotary member formed with a through hole which is non-rotatably mounted on the shaft on a side opposing to the field coil; an input-side rotary member which is rotatably mounted on the shaft; a drive transmitting member which is rotatable together with the input-side rotary member for transmitting a drive power from the input-side rotary member to the output-side rotary member; and an elastic member for allowing the drive transmitting member to shift from the input-side rotary member side to the output-side rotary member side when the energizing coil is energized, wherein a cross section of the shaft and a cross section of the through hole of the output-side rotary member at respective mutually contacting surfaces are so configured that the shaft is capable of moving in and out of the through hole of the output-side rotary member without substantially deforming the mutually contacting surfaces between the shaft and the output-side rotary member.
In this arrangement, the output-side rotary member is mounted onto the shaft in a relative non-rotatable state by merely inserting the shaft into the through hole of the output-side rotary member. Accordingly, a press-fitting or swaging operation, which has been required in assembling the electromagnetic clutch of prior art, becomes unnecessary, thereby simplifying the assembling operation. Further, since the press-fitting or swaging is not necessary in this arrangement, the output-side rotary member is free from an undesirable external stress which may result in a mechanical distortion of the output-side rotary member, thus preventing occurrence of magnetic attraction force variation which may adversely affect a performance of the drive transmitting member.
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments/examples.
REFERENCES:
patent: 4079821 (1978-03-01), Miller
patent: 4346616 (1982-08-01), Geisslinger et al.
patent: 4664238 (1987-05-01), Nishino et al.
patent: 4955954 (1990-09-01), Onishi et al.
patent: 4984668 (1991-01-01), Onishi et al.
patent: 5036368 (1991-07-01), Nakamura
patent: 5038905 (1991-08-01), Nakamura
patent: 5080214 (1992-01-01), Fossum
patent: 5148902 (1992-09-01), Nakamura
patent: 5735375 (1998-04-01), Booth et al.
patent: 5762173 (1998-06-01), Nishimura
patent: 5862906 (1999-01-01), Howrie
patent: 6031309 (2000-02-01), Nishimura
patent: 6112872 (2000-09-01), Miwa et al.
Bonck Rodney H.
Jordan and Hamburg LLP
Kyocera Mita Corporation
Rodriguez Saul
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