Starter having helical ventilation groove in tube
AssigneeDenso Corporation
InventorsToyohisa Yamada, Shinji Usami
Life of this patent
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Abstract
In a starter, a cylindrical tube is slidablly engaged with an outer peripheral surface of an output shaft through a bearing in an axial direction. A front end of the tube, which supports a pinion, is closed to define an enclosed space between the front end of the tube and an end of the output shaft. A ventilation groove is formed on an inner cylindrical surface of the tube to communicate the enclosed space with a space defined rearward of the bearing. The ventilation groove has a helical shape twisted about an axis of the tube. When the bearing is press-fitted in the tube, a direction of press-fitting the tube and a direction along the ventilation groove do not coincide, but cross each other.
Claims7
A starter for starting an engine by transmitting a rotation force of a motor to a ring gear through a pinion, the starter comprising:
- an output shaft rotated with an operation of the motor;
- a cylindrical tube engaging with an outer peripheral surface of the output shaft to be slidable in an axial direction through a bearing fitted in the tube, the cylindrical tube having a first and second ends, the first end supporting the pinion and being closed to define an enclosed space between the first end and an end of the output shaft;
- and
- a one-way clutch for transmitting a rotation of the output shaft to the tube, wherein:
- the tube has a ventilation groove on an inner cylindrical surface to communicate the enclosed space with a space defined in a proximity of the second end of the tube, the ventilation groove being formed into a helical shape twisted about an axis of the tube,
- the ventilation groove is twisted in a direction opposite to a rotation direction of the tube from the second end toward the first end of the tube,
- the bearing is press-fitted to the inner cylindrical surface of the tube,
- the ventilation groove is formed on the inner cylindrical surface of the tube and is located on a radially outside of the bearing,
- the ventilation groove defines a groove first end that is open on the inner cylindrical surface axially between the first end of the tube and an end of the bearing and a groove second end that is open on the inner cylindrical surface axially between the second end of the tube and an opposite end of the bearing,
- the ventilation groove has a first end and second end, and the first and second ends are situated at circumferentially different positions in a cylindrical surface area of less than 180 degrees,
- the first and second ends of the groove are situated without overlapping in the circumferential direction, and
- the bearing is a wrapping bearing formed by rounding substantially a rectangular-shaped plate into a cylindrical shape.
Dependencies are inferred from the claim text.