Rotary shafts – gudgeons – housings – and flexible couplings for ro – Overload release coupling
Reexamination Certificate
2000-01-04
2001-05-22
Bonck, Rodney H. (Department: 3681)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Overload release coupling
C192S056500, C417S223000
Reexamination Certificate
active
06234904
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a drive power transmission apparatus disconnectably connecting a first rotating element on the side of a drive power source with a second rotating element on the side of a drive-power-receiving unit for transmitting a drive power from the first rotating element to the second rotating element. More particularly, the present invention relates to a drive power transmission apparatus, not exclusively, but preferably, arranged between a vehicle engine and a vehicle auxiliary unit, such as a refrigerant compressor of a vehicle refrigerating system, and accommodating therein a transmission-interrupting mechanism for interrupting the transmission of a drive power from the vehicle engine to the auxiliary unit to stop the operation of the auxiliary unit when an excessive load appears in the auxiliary unit due to an unpredictable trouble of the auxiliary unit, in order to eventually prevent the excessive load being transmitted to the vehicle engine.
2. Description of the Related Art
The pending U.S. patent application Ser. No. 09/208,383 assigned to the Assignee of the present application discloses a drive power transmission apparatus with a transmission interrupting means. The disclosed drive power transmission apparatus includes a power transmission-pulley-assembly
100
having a torque limiter, as shown in the attached
FIGS. 8 through 12
.
As shown in
FIGS. 8 and 9
, the power transmission-pulley-assembly
100
includes a rotor element
101
rotatably supported on a front housing
201
of a refrigerant compressor and having an axis of rotation corresponding to an axis “L” shown in
FIG. 8
about which the power transmission-pulley-assembly
100
rotates. The rotor element
100
is operatively connected to a vehicle engine
202
via a transmission belt
203
wound around both the rotor element
101
and a pulley mounted on an output shaft of the vehicle engine.
The rotor element
101
is provided with an annularly extending inner cavity
101
a
and spring catches
102
formed therein to be arranged in the inner cavity
101
a
. Each of the spring catches
102
has a portion thereof projecting from the inner cavity
101
a
and an engaging recess
103
recessed in an end face of the spring catch
102
, i.e., in a front face thereof in a predetermined rotating direction of the power transmission-pulley-assembly
100
, indicated by an arrow in FIG.
9
. The engaging recess
103
is formed to extend from the inside of the inner cavity
101
a
toward the outside of the inner cavity
101
a
. The engaging recess
103
of each spring catch
102
opens in a radial direction of the power transmission-pulley-assembly
100
and is closed by walls in a direction parallel to the axis “L”. The engaging recess
103
has an engaging end face
103
a
formed in the inner cavity
101
a
as a face through which a power is transmitted from the rotor element
101
to a later-described spiral spring
104
. The engaging end face
103
a
of the engaging recess
103
is arranged to direct forwardly with respect to the rotating direction of the power transmission-pulley-assembly
100
. One of the walls of the engaging recess
103
is formed as a blocking face
103
b
facing toward the inside of the inner cavity
101
a
, i.e., facing in a direction from the left to right hand along the axis “L” in FIG.
8
.
The power transmission-pulley-assembly
100
is further provided with a pair of spiral springs
104
arranged between the rotor element
101
and a drive shaft
204
of the refrigerant compressor. Each spiral spring
104
has an outer end
104
a
which is received in the engaging recess
103
of the spring catch
102
so as to be abutted against the engaging end face
103
a
thereof. The inner end
104
b
of the spiral spring
104
is fixed to the drive shaft
204
in a region outside the inner cavity
101
a
of the rotor element
101
.
The spiral springs
104
shown in
FIG. 11
are placed in a free condition where the springs
104
recover their basic position lying in a flat plane which is vertical to the axis “L” and is located in front of the rotor element
101
in a direction of the axis “L”, so that the outer end
104
a
thereof is detached from the spring catch
102
. Thus, when the power transmission-pulley-assembly
100
is assembled on the front end of the refrigerant compressor, the spiral spring
104
is elastically deformed in the direction of the axis “L” so that the outer end
104
a
thereof is moved rearward from the above-mentioned flat plane with respect to the inner end
104
b
so as to be engaged in the engaging recess
103
of the spring catch
102
, as shown in FIG.
8
. When the outer end
104
a
of the spiral spring
104
is engaged in the engaging recess
103
of the spring catch
102
, the outer end
104
a
is elastically urged frontward in a direction along the axis “L” to come into contact with the blocking face
103
b
, so that an elastic force is produced and stored in the spiral spring
104
.
A disconnecting plate
105
of the power transmission-pulley-assembly
100
is fixed to the drive shaft
204
and arranged axially in front of the spiral spring
104
along the axis “L”. The disconnecting plate
105
is provided with a pair of circularly elongated projections
105
a
formed therein and functioning as a releasing means for permitting the outer end
104
a
of the spiral spring
104
to be disengaged from the engaging recess
103
of the spring catch
102
. The disconnecting plate
105
is fixedly mounted on the drive shaft
204
so that each of the pair of circularly elongated projections
105
a
is shifted circumferentially in the rotating direction of the transmission-pulley-assembly
100
with respect to the corresponding one of the pair of spring catches
102
.
A drive power from the vehicle engine
202
is transmitted to the drive shaft
204
via the transmission belt
203
, the rotor element
101
, the engaging end face
103
a
of the spring catch
102
, and the spiral spring
104
having the outer and inner ends
104
a
and
104
b
. As soon as the drive power is transmitted to the drive shaft
204
to rotate it in the predetermined rotating direction shown in
FIG. 9
, the drive shaft
204
is subjected to a load torque in a direction reverse to the predetermined rotating direction thereof. The load torque applied to the drive shaft
204
causes torsion of the spiral spring
104
, so that the rotor element
101
is relatively shifted circumferentially with respect to the drive shaft
204
in a direction corresponding to the predetermined rotating direction of the drive shaft
204
. Thus, each of the spring catches
102
integral with the rotor element
101
approaches the corresponding releasing projection
105
a
of the disconnecting plate
105
fixed to the drive shaft
204
.
When the above-mentioned load torque is smaller than a predetermined limiting torque, an amount of torsion of the spiral spring
104
is kept small and accordingly, the relative amount of shift between the rotor element
101
and the drive shaft
204
is also kept small. Thus, although the releasing projections
105
a
of the disconnecting plate
105
are shifted to positions close to or in contact with the outer ends
104
a
of the spiral springs
104
, the contacting force acting between the outer ends
104
a
of the spiral springs
104
and the releasing projections
105
a
is not large enough to release a mechanical engagement of the outer ends
104
a
of the spiral springs
104
with the rotor element
101
via the engaging end face
103
a
of the spring catch
102
. Therefore, the outer ends
104
a
of the spiral springs
104
are engaged in the engaging recesses
103
of the spring catch
102
so that the outer ends
104
a
are kept in touch with the engaging end face
103
a
. Accordingly, the transmission of the drive power from the vehicle engine
202
to the drive shaft
204
continues. A change in the load torque can be absorbed by the torsion of the spiral springs
104
so long as the cha
Kawaguchi Masahiro
Okada Masahiko
Tanaka Hirohiko
Uryu Akifumi
Bonck Rodney H.
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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