US 5,706,700 AGranted

Overrunning clutch for starters

AssigneeNippondenso Co., Ltd.

InventorsYoshito Takagi, Tsutomu Shiga, Yasuhiro Nagao

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Abstract

An overrunning clutch that can absorb the impact torque, and accurately and easily conveys the maximum torque. A clutch outer tubular portion and inner tubular portion are separately fixed on an internal gear and a center case of an epicycle gear reduction mechanism. A wedge-shaped groove is formed on one of an inner circumference of the outer tubular portion and an outer circumference of the inner tubular portion to accomodate a rolling element. A fitting concave portion to fit the rolling element is formed on the other one of the inner circumference of the outer tubular portion and the outer circumference of the inner tubular portion. With this, the torque value generated when the rolling element leaves the fitting concave portion can be accurately set just by setting the depth of the fitting concave portion. The radial force that acts on the opposite direction of the tubular portions holding the rolling element can be reduced. This allows the strength of the tubular portions to be reduced, and the weight to be lightened. As the torque is not conveyed with frictional force, the wear is also reduced.

Claims16

Dependent claims

A starter structure having an overrunning clutch, comprising:

a starter motor;
a drive shaft constructed and arranged to be driven by said starter motor;
a pinion axially movably mounted on said drive shaft and constructed and arranged to be selectively engageable with an engine ring gear;
the overrunning clutch being disposed to regulate transmission of torque between said starter motor and said pinion, said overunning clutch including:
an outer tubular portion and an inner tubular portion placed with a clearance therebetween in the radial direction and facing so as to rotate freely relative to one another, one of said outer tubular portion and said inner tubular portion being fixed;
at least one rolling element;
at least one wedge-shaped groove which accommodates said rolling element, each said groove being formed concavely on one of an inner circumference of said outer tubular portion and an outer circumference of said inner tubular portion;
and
at least two concave portions each of which selectively fittingly engages said rolling element, said at least two concave portions being formed concavely on an other one of said inner circumference of said outer tubular portion and said outer circumference of said inner tubular portion, a depth of each said concave portion being determined to keep said rolling element received therein while said rolling element is kept pressed to an end wall of said wedge-shaped groove when a predetermined starter drive torque usually required for starting an engine is applied between said outer tubular portion and said inner tubular portion, said depth of each said concave portion further being a value such that said rolling element can move from one concave portion to an other concave portion while said rolling element is kept pressed to the end wall of said wedge-shaped groove when an excessive impact torque, exceeding the predetermined starter drive torque usually required for starting an engine, is applied between said outer tubular portion and said inner tubular portion in a direction to move said rolling element toward a short depth side of said wedge-shaped groove, thereby reducing said excessive impact torque.

6 more elements

A starter with an overrunning clutch comprising:

an armature shaft rotated by a starter motor;
a drive shaft coaxially disposed with said armature shaft and operatively coupled with said armature shaft;
and
a clutch mechanism operatively coupling said shafts and having a cylindrical clutch outer member, a cylindrical clutch inner member coaxially disposed in said clutch outer member, and a plurality of rollers disposed between said clutch outer member and said clutch inner member,
wherein one of said clutch outer member and said clutch inner member is fixed;
wherein one of said clutch outer member and said clutch inner member is formed with a plurality of wedge-shaped spaces for accommodating said rollers therein and an other of said clutch outer member is formed with a plurality of indentations for each of said wedge-shaped spaces,
wherein a depth of each of said indentations is determined to keep said rolling element received therein while said rolling element is kept pressed to an end wall of said wedge-shaped space upon application of a predetermined starter drive torque usually required for starting an engine, said depth of each of said indentations further being determined to be a value whereby each of said rollers is enabled to move from one indentation to another while said rolling element is kept pressed to an end wall of said wedge-shaped space upon application of excessive torque, exceeding a torque usually required for starting an engine, in a direction from said armature shaft to said drive shaft under a condition that said clutch outer member and said clutch inner member are locked to each other through said rollers.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/705,041Filed 30 Aug 1996 · continuation
Priority: JP 6-2137077 Sep 1994
Granted: 13 Jan 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

F02N 15/023
The starter comprising an intermediate clutch: of the overrunning type
F16D 41/064
With intermediate wedging coupling members between an inner and an outer surface: the intermediate members wedging by rolling and having a…
Y10T 74/134
Automatic: clutch connection
F02N
Starting of combustion engines

Family

Serial381,498Parent of this continuation · filed 31 Jan 1995
US 5,706,700 AThis patent

From the US filing history. Foreign family members aren’t listed.

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