Motor having rotatable shaft coupled with worm shaft

Details Motor having rotatable shaft coupled with worm shaft Motor having rotatable shaft coupled with worm shaft

2002-04-12

2004-04-27

Mullins, Burton S. (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S071000, C310S180000, C310S049540, C310S089000

Reexamination Certificate

active

06727613

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. 2001-127582 filed on Apr. 25, 2001, Japanese Patent Application No. 2001-131523 filed on Apr. 27, 2001 and Japanese Patent Application No. 2002-008850 filed on Jan. 17, 2002.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a motor including a clutch, which couples a rotatable shaft of a rotor to a worm shaft.
2. Description of Related Art
With reference to
FIG. 17
, one previously proposed motor used, for example, in a power window system includes a motor main body
52
, a speed reducing unit
54
and a clutch
55
. The motor main body
52
rotates a rotatable shaft
51
. The speed reducing unit
54
includes a worm shaft
53
and transmits rotational driving force of the worm shaft
53
to a load side (e.g., a door window glass side of the power window system). The clutch
55
is placed between the rotatable shaft
51
and the worm shaft
53
.
With reference to
FIG. 18
, the clutch
55
includes a driving-side rotator
61
, a driven-side rotator
62
, a collar
63
and rolling elements
64
. The driving-side rotator
61
is connected to a distal end of the rotatable shaft
51
to rotate integrally therewith. The driven-side rotator
62
is integrally connected to a base end of the worm shaft
53
. The collar
63
surrounds both the driving-side rotator
61
and the driven-side rotator
62
and is secured to a gear housing
56
of the speed reducing unit
54
. The rolling elements
64
are arranged between the driven-side rotator
62
and the collar
63
. In the clutch
55
, when the driving-side rotator
61
is rotated, each rolling element
64
is rotated together with the driving-side rotator
61
without being clamped between a corresponding control surface
62
a
of the driven-side rotator
62
and an inner peripheral surface
63
a
of the collar
63
, and the driven-side rotator
62
is engaged with and is rotated by the driving-side rotator
61
in a rotational direction. On the other hand, when rotational force is applied to the driven-side rotator
62
from the load side (worm shaft
53
side) to rotate the driven-side rotator
62
, each rolling element
64
is clamped between the corresponding control surface
62
a
of the driven-side rotator
62
and the inner peripheral surface
63
a
of the collar
63
to restrain the rotation of the driven-side rotator
62
.
Thus, when the rotatable shaft
51
is rotated by the motor main body
52
, the rotational driving force of the rotatable shaft
51
is transmitted to the worm shaft
53
through the clutch
55
to raise or lower the window glass. On the other hand, when load (e.g., weight of the window glass or vibrations of the window glass) is downwardly applied to the window glass to apply rotational force to the worm shaft
53
, the rotation of the worm shaft
53
is restrained by the clutch
55
to restrain the unexpected downward movement of the window glass.
In order to properly operate the clutch
55
, the driving-side rotator
61
and the driven-side rotator
62
are installed such that a rotational axis of the driving-side rotator
61
is aligned with a rotational axis of the driven-side rotator
62
. Furthermore, a connecting hole
61
a
is formed in a central portion of the driving-side rotator
61
to extend in an axial direction. A connecting portion
51
a
formed in a distal end of the rotatable shaft
51
is press fitted into the connecting hole
61
a
of the driving-side rotator
61
, so that the rotatable shaft
51
and the driving-side rotator
61
are connected to each other to rotate together. Thus, it is required to assemble the motor such that the central axis of the driving-side rotator
61
(connecting hole
61
a
) and the central axis of the rotatable shaft
51
are aligned with each other.
However, for example, due to a manufacturing error of each corresponding connecting portion, misalignment between the rotational axis of the driving-side rotator
61
and the rotational axis of the rotatable shaft
51
(e.g., tilt of the rotational axis of the rotatable shaft
51
relative to the rotational axis of the driving-side rotator
61
, or radial displacement of the rotational axis of the rotatable shaft
51
relative to the rotational axis of the driving-side rotator
61
, which extends parallel to the rotational axis of the rotatable shaft
51
) can occur. When the misalignment occurs, relatively large radial loads are applied to the connection between the driving-side rotator
61
and the rotatable shaft
51
. If the driving-side rotator
61
and the rotatable shaft
51
are rotated at this state, relatively large noises and vibrations are generated at the connection between the driving-side rotator
61
and the rotatable shaft
51
.
SUMMARY OF THE INVENTION
The present invention addresses the above disadvantages. Thus, it is an objective of the present invention to provide a motor capable of reducing generation of noises and vibrations at a connection between a rotatable shaft of a rotor and a worm shaft.
To achieve the objective of the present invention, there is provided a motor including a motor main body, a speed reducing unit and a coupling means. The motor main body includes a rotatable shaft and rotates the rotatable shaft. The speed reducing unit is connected to the motor main body and includes a worm shaft. The worm shaft is substantially coaxial with the rotatable shaft. The coupling means couples the rotatable shaft with the worm shaft. The coupling means includes a driving-side rotator and a driven-side rotator. The driving-side rotator is connected with the rotatable shaft to rotate integrally with the rotatable shaft. The driven-side rotator is connected with the worm shaft to rotate integrally with the worm shaft and is engageable with the driving-side rotator in a rotational direction. The rotatable shaft includes a connecting portion. The driving-side rotator includes a connecting portion, which is loosely fitted with the connecting portion of the rotatable shaft and is engageable with the connecting portion of the rotatable shaft in the rotational direction to rotate integrally with the connecting portion of the rotatable shaft.
To achieve the objective of the present invention, there is also provided a motor including a motor main body, a brush holder, a speed reducing unit, a coupling means and a positioning means. The motor main body includes a yoke housing. The yoke housing rotatably receives an armature, which includes a rotatable shaft and a commutator. The brush holder is placed in an opening of the yoke housing. The brush holder holds a plurality of brushes in sliding contact with the commutator and includes a bearing, which rotatably supports the rotatable shaft. The speed reducing unit includes a gear housing connected to the yoke housing in such a manner that the brush holder is arranged between the opening of the gear housing and an opening of the yoke housing. The gear housing rotatably receives a worm shaft, which is substantially coaxial with the rotatable shaft. The coupling means couples the rotatable shaft with the worm shaft. The positioning means is placed between the brush holder and the gear housing for positioning the brush holder and the gear housing relative to each other.


REFERENCES:
patent: 5090261 (1992-02-01), Naktsukasa
patent: 6215209 (2001-04-01), Yamamato
patent: 6242824 (2001-06-01), Torii
patent: 6288464 (2001-09-01), Torii
patent: 6491131 (2002-12-01), Appleyard
patent: 6550599 (2003-04-01), Kudou
patent: 6591708 (2003-07-01), Kobayashi

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