Geared motor and geared motor series

Details Geared motor and geared motor series Geared motor and geared motor series

2000-10-03

2002-11-26

Estremsky, Sherry (Department: 3681)

Interrelated power delivery controls, including engine control

Brake control

Sensed condition responsive control of engine of brake

C477S190000, C074S60600R, C475S269000

Reexamination Certificate

active

06485394

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a geared motor having a motor unit and a change gear unit for transmitting rotational power from this motor unit in combination, and a geared motor series from which this geared motor can be constructed.
2. Description of the Related Art
Geared motors comprising a motor unit for generating rotational power and a change gear unit for reducing or increasing the speed of the rotational power in combination are widely used in every industrial field, because their motor speeds are mechanically reduced or increased, they are capable operating their motor units in a most efficient state (revolution range).
For example, a conventional geared motor
1
shown in
FIG. 10
comprises a motor unit
2
and a change gear unit
4
for transmitting rotational power from the motor unit
2
in combination.
This motor unit
2
has a mounting surface consisting of a square motor flange
10
formed thereon at the top side of its motor shaft
6
. This motor flange
10
has bolt holes
10
A formed therethrough at the four corners. The motor shaft
6
is located at the center of the motor flange
10
.
The motor unit
2
outputs rotational power through the motor shaft
6
. As shown in
FIG. 9
, the end of this motor shaft
6
is splined so as to support a helical motor pinion
8
rotatively.
The change gear unit
4
has a three-stage reduction structure. Specifically, the change gear unit
4
comprises: a first gear
12
meshing with the motor pinion
8
; a first pinion
14
for making coaxial, integral rotation with the first gear
12
; a second gear
16
meshing with the first pinion
14
; a second pinion
18
for making coaxial, integral rotation with the second gear
16
; an output shaft gear
20
meshing with the second pinion
18
; an output shaft
22
supported by a bearing, for making integral rotation with the output shaft
22
; and a casing
24
for accommodating these change gear mechanisms.
A shaft insertion hole
24
A to which the motor shaft
6
is inserted is formed through the casing
24
. The casing
24
is also provided with tapped holes
24
B formed at the individual corners of a square with the shaft insertion hole
24
A at the center. The shaft insertion hole
24
A and the four tapped holes
24
B are arranged to coincide with the motor shaft
6
and the four bolt holes
10
A in the motor flange
10
of the motor unit
2
, respectively, so that the motor unit
2
and the change gear unit
4
are coupled to each other by four bolts
26
, as shown in FIG.
10
.
In this geared motor
1
, rotational power from the motor unit
2
is transmitted through the individual pinions and gears to the output shaft
22
at a predetermined reduction ratio.
For this type of geared motor
1
, in general, a plurality of serialized change gear units
4
set at change gear ratios with predetermined intervals (common ratios) are provided in advance. Of these, one change gear unit
4
having the change gear ratio closest to an actually-required change gear ratio is combined with the motor unit
2
to construct a geared motor
1
.
As described above, a user of the geared motor
1
selects a change gear unit
4
having the most appropriate change gear ratio from among the series with a variety of change gear ratios. According to the use patterns of the geared motor
1
, however, a modification to the change gear ratio is sometimes needed afterwards. Possible measures to be taken here include the following:
1) Replace the change gear unit
4
with a new one having an optimum change gear ratio
2) Add a change gear unit having an adjusting change gear ratio to between the change gear unit
4
and the motor unit
2
.
The measures 1), however, require purchase of the new change gear unit
4
, giving rise to an increase in cost and a problem of wasting the change gear unit
4
used heretofore.
As for the measures 2), the change gear unit
4
used previously was intended for to-motor coupling in the first place. Therefore, the interposition of a change gear unit between the change gear unit
4
and the motor unit
2
was often difficult in practice, and involved considerable problems. The reasons therefor will be described in concrete terms hereinafter.
A first problem is that the change gear unit
4
has a mounting surface structure of “receiving” type alone, and hence it is physically difficult to couple an additional (other-than-motor-unit) change gear unit or the like (hereinafter, referred to as insert unit) thereto.
A motor unit
2
is always coupled to an apparatus to be driven (mating machine) such as the change gear unit
4
. To facilitate this coupling, there is typically provided a motor flange
10
as shown in FIG.
10
. This aims to insert bolts
26
to the bolt holes
10
A from the motor side, and threadedly engage the bolts
26
with the tapped holes
24
B on the mating-machine side to allow the coupling.
As a result of this, many reduction gear units
4
simply have a structure of “receiving” it. More specifically, reduction gear units
4
often have nothing but simple tapped holes
24
B formed at the individual corners of a square around their shaft insertion hole
24
A to which the motor shaft
6
is inserted; that is, there is little assumption that the coupling may be established by bolting from the reduction-unit-
4
side.
Turning now to an insert unit itself, suppose that the change gear mechanism in the insert unit has a parallel axis gear structure containing pinions and gears in combination. In a single-stage reduction mechanism, it would be impossible for the insert unit to establish coaxiality between the motor shaft
6
inserted thereto and its own output shaft for transmitting the rotation of the motor shaft
6
to the reduction gear unit
4
. Therefore, two or more stages (two or more pairs of gears and pinions) are logically required in order to make coaxial the motor shaft
6
and the output shaft in the insert unit. The insertion unit thus becomes complicated in internal structure, as well as extended along the axial direction of the motor shaft
6
.
A second problem is that even though the main objective is to make an adjustment in change gear ratio, it is not always possible to achieve a user-intended change gear ratio.
Change gear units, as described before, are serialized with change gear ratios of regular intervals in advance. Therefore, combining the same with serialized insert units of another types cannot always achieve a desired change gear ratio. That is, combinations of change gear ratios obtainable from ordinary geared speed-change units lead to only a limited variation of change gear ratios, failing to make fine adjustments according to an actual change gear ratio needed.
A third problem is that combining two change gear units increases noise greatly. To be more specific, there occur the problems that the change gear units combined produce resonance with each other, and that a rise in the number of gears makes the gears themselves produce higher noise.
SUMMARY OF THE INVENTION
The present invention has been achieved in view of the foregoing problems. It is thus an object of the present invention to provide a geared motor which can meet user needs for change gear ratios with flexibility and reliability as well as suppresses an increase in noise, and a geared motor series from which a plurality of types of such geared motors can be constructed.
The invention according to claim
1
achieves the foregoing object by the provision of a geared motor comprising a motor unit and a change gear unit for transmitting rotational power from the motor unit in combination, the change gear unit being arranged with its input shaft coaxial to a motor shaft of the motor unit, wherein: a simple planetary roller unit including a simple planetary roller mechanism and a casing for accommodating the simple planetary roller mechanism is interposed between the change gear unit and the motor unit, the simple planetary roller mechanism having a sun roller, a planetary roller retained by a carrier, and a ring roller, th

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