192 clutches and power-stop control – Clutches – Automatic
Reexamination Certificate
2002-12-31
2004-06-15
Rodriguez, Saúl J. (Department: 3681)
192 clutches and power-stop control
Clutches
Automatic
C192S11000B
Reexamination Certificate
active
06749050
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a pulley apparatus with built-in one-way clutch.
2. Description of the Related Art
A pulley apparatus with built-in one-way clutch is fastened to the end of the rotating shaft of an alternator in the generator of an automobile, for example, to drive the alternator by running an endless belt between the drive pulley attached to the end of the engine crankshaft and the pulley apparatus with built-in one-way clutch.
The construction of the alternator, which generates the power required for the automobile using as the drive source the engine for running the automobile, is disclosed for example in Japanese Patent Publication No. Toku Kai Hei 7-139550.
FIG. 3
shows the alternator
1
disclosed in this publication. This alternator
1
comprises a housing
2
, and rotating shaft
3
on the inside of the housing
2
. The rotating shaft
3
is supported by a pair of rolling bearings
4
such that it rotates freely. There is a rotor
5
and commutator
6
in the middle of the rotating shaft
3
. Also, a pulley
7
is fixed to one end (right end in
FIG. 3
) of the rotating shaft
3
on the section that protrudes to the outside of the housing
2
. When installed in an engine, an endless belt is extended around this pulley
7
and the engine crankshaft drives the rotating shaft
3
.
Conventionally, a pulley
7
was simply fixed to the rotating shaft
3
. However, recently, various kinds of one-way clutch built-in pulleys for alternators have been proposed, wherein when the running speed of the endless belt is constant or increasing, power is freely transmitted from the endless belt to the rotating shaft, and when the running speed of the endless belt is decreasing, the relative rotation between the pulley and the rotating shaft is free, and these pulleys are being used in some applications. For example, a one-way clutch built-in pulley for an alternator as described above has been disclosed in Japanese Patent Publications Nos. Toku Kai Sho 56-101353, Toku Kai Hei 8-226462, Toku Kai Hei 9-229097, Toku Kai Hei 11-22753, Toku Kai Hei 11-159599, Toku Ko Hei 7-72585, and French patent FR2726059A1 etc. Also, this kind of pulley apparatus with built-in one-way clutch for an alternator is actually being used in some applications.
FIG. 4
shows the pulley apparatus with built-in one-way clutch for an alternator that is disclosed in Japanese Patent Publication No. Toku Kai Hei 11-22753. This pulley apparatus with built-in one-way clutch for an alternator has a sleeve
8
that can be fitted over the tip end of the rotating shaft
3
(see
FIG. 3
) of the alternator
1
. In addition, there is a pulley
7
located around this sleeve
8
such that it is concentric with the sleeve
8
. There is a pair of support bearings
9
and the one-way clutch
10
located between the outer peripheral surface of the sleeve
8
and the inner peripheral surface of the pulley
7
.
The support bearings
9
support radial loads that are applied to the pulley
7
, while at the same time make it possible for free relative rotation between the sleeve
8
and pulley
7
.
The one-way clutch
10
transmits rotation power from the pulley
7
to the sleeve
8
only when the pulley
7
rotates in a specified direction with respect to the sleeve
8
.
The one-way clutch
10
has an inner ring
11
for the one-way clutch that is fitted onto and fixed around the middle section in the axial direction of the sleeve
8
. There is a plurality of depressions
12
, called ramp sections, are formed at uniform intervals all the way around in the circumferential direction on the outer peripheral surface of the inner ring
11
for the one-way clutch. This outer peripheral surface functions as a cam surface
13
. In contrast to this, there is an outer ring
14
that is fitted into and fixed around the inner peripheral surface of pulley
7
. The middle section in the axial direction of this outer ring
14
functions as the outer ring for the aforementioned one-way clutch
10
. Therefore, the inner peripheral surface of the middle section in the axial direction of the outer ring
14
is simply a cylindrical surface generally along its entire length in the axial direction. The one-way clutch
10
comprises the middle section in the axial direction of the outer ring
14
, the inner ring
11
for the one-way clutch and a plurality of rollers
15
. The plurality of rollers
15
are supported by a clutch retainer
16
such that they rotate freely and can displace a little in the circumferential direction. In addition, there are springs between the column sections of the clutch retainer
16
and the rollers
15
. A cylindrical-shaped space is formed between the outer peripheral surface of the cam surface
13
and the inner peripheral surface in the middle section in the axial direction of the outer ring
14
. In the cylindrical-shaped space, the springs elastically press against the rollers
15
in the direction of the section where the width in the radial direction becomes narrow.
On the other hand, outer bearing races
18
for the support bearings
9
are fitted around the inner peripheral surfaces of the sections near both ends in the axial direction of the outer ring
14
that is fitted and fixed around the inner peripheral surface of the pulley
7
, and inner bearing races
19
for the support bearings
9
are fitted around the outer peripheral surfaces of the sections on both ends in the axial direction of the sleeve
8
. Also, a plurality of rolling elements (balls)
22
are located between the outer-ring raceways
20
that are formed around the inner peripheral surfaces of the outer bearing races
18
, and the inner-ring raceways
21
that are formed around the outer peripheral surfaces of the inner bearing races
19
.
Moreover, an attachment protrusion
17
protruding radially inward is formed part way around in the circumferential direction on the inner peripheral surface of one end (right end in
FIG. 4
) in the axial direction of the clutch retainer
16
. This attachment protrusion
17
is held between the end surface of the inner ring
11
for the one-way clutch and the end surface of the inner bearing race
18
of one of the support bearings (right bearing in FIG.
4
).
The reason for using a pulley apparatus with built-in one-way clutch for an alternator is as follows. There are changes in rotation speed of the engine crankshaft when firing occurs, and in the case of a diesel engine or direct-injection gasoline engine, changes in rotational angular speed of the crankshaft become especially large at low rotational speed such as during idling. As a result, the running speed of the endless belt
23
that extends around the drive pulley that is fastened to the end of the crankshaft also changes small. On the other hand, the rotating shaft
3
of the alternator
1
is rotated and driven by the endless belt
23
by way of the pulley
7
, and there is no sudden change due to the inertial mass of the rotating shaft
3
and the rotor
5
and commutator
6
(see
FIG. 3
) that are fastened to the rotating shaft
3
. Therefore, when the pulley
7
is simply fastened to the rotating shaft
3
, the number of revolution of the rotating shaft
3
decreases as is when the running speed of the belt drops, so that the generating efficiency of the alternator decreases. At the same time, there is a tendency for rubbing in both directions between the endless belt
23
and the pulley
7
due to the change in the rotational angular speed of the crankshaft.
As a result, stress that repeatedly changes direction acts on the endless belt
23
that it rubs with the pulley
7
, and thus slipping occurs easily between this endless belt
23
and pulley
7
, or causes the life of the endless belt
23
to be shortened.
Moreover, the drop in the generating efficiency of the alternator
1
described above, and the decrease in life of the endless belt
23
due to friction between the outer peripheral surface of the pulley
7
and the inner peripheral surface of the endless belt
23
are also
NSK Ltd.
Rodriguez Saúl J.
LandOfFree
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