Starter

• US 5,549,011 A
• Filed: 02/22/1995
• Issued: 08/27/1996
• Est. Priority Date: 09/19/1994
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Hayashi, Nobuyuki, Shiga, Tsutomu, Nagao, Yasuhiro, Ohmi, Masanori
• Primary Examiner(s): Herrmann, Allan D.
• Application Number:
  US08/392,111
• Time in Patent Office: 552 Days
• Field of Search: 74/6, 74/7 A, 74/7 C, 74/7 E, 188/82.84, 192/42, 192/45, 475/318
• US Class Current: 74/7.00E
• CPC Class Codes: F02N 15/023 of the overrunning type
• CPC Class Codes: F16D 41/064 the intermediate members wedging by rolling and having a circular cross-section, e.g. balls F16D41/061 takes precedence
• CPC Class Codes: Y10T 74/132 Separate power mesher
• CPC Class Codes: Y10T 74/134 Clutch connection
• CPC Class Codes: Y10T 74/137 Reduction gearing

Abstract

A starter having a highly reliable overrunning clutch which has grooves on both a clutch member inner and a clutch outer member. Rollers are sandwiched from the front and rear torque conveyance direction by the roller contact surface of each groove, so a large stress such as with the roller-type overrunning clutch using the wedge-effect is not applied on each contact surface and roller contact surface. This reduces the inertia of the clutch, and suppresses the impact force generated when a pinion engages an engine ring gear.

Claims

1. A starter comprising:

an electric motor having an armature shaft;

an output shaft engageable with an engine ring gear; and

an overrunning clutch disposed between said armature shaft and said output shaft, said clutch including a clutch inner member shaped in a cylindrical form and having first grooves on an outer circumference thereof, a clutch outer member shaped in a cylindrical form and having second grooves on an inner circumference thereof opposing said outer circumference of said clutch inner member, and rollers set between said clutch inner member and said clutch outer member,

wherein at least one of said clutch inner member and said clutch outer member is formed of a resin or nonferrous metal, and

wherein one of said first and second grooves has a radial depth that can store said rollers therein so that said rollers allow noncontact relation between said clutch outer member and said clutch inner member during overrunning of said output shaft.

2. The starter according to claim 1, wherein said second grooves of said clutch member outer have said radial depth to store said rollers to a position where said outer circumference of said clutch inner member is not contacted by said rollers.

3. The starter according to claim 2, wherein the number of said first grooves of said clutch inner member is greater than that of said second grooves.

4. The starter according to claim 2, wherein said first grooves have a curvature radius approximately the same as a radius of said rollers.

5. The starter according to claim 1, wherein part of said first and second grooves have a curvature radius approximately the same as a radius of said rollers, and wherein said rollers contact both said first and second grooves.

6. The starter according to claim 1, wherein said one of said first and second grooves extend radially and circumferentially, and all of said grooves have respective fitting surfaces which receive said roller thereon for torque transmission in a circumferential direction.

7. The starter according to claim 6, wherein an other of said first and second grooves include an inclined roller guide surface that leads to the roller fitting portion.

8. The starter according to claim 3, wherein the number of said first grooves is an integer multiple of the number of said rollers and all of said rollers are received in said second grooves at the same time, said integer multiple being equal to two or more.

9. The starter according to claim 8, wherein said first grooves have a curvature radius approximately the same as a radius of said rollers.

10. The starter according to claim 8, wherein part of said first and second grooves have a curvature radius approximately the same as a radius of said rollers, and wherein said rollers contact both said first and second grooves.

11. A starter comprising:

an electric motor including an armature shaft;

an output shaft for driving an engine when driven by said armature shaft; and

an overrunning clutch operatively coupling said armature shaft and said output shaft, said clutch including an inner cylindrical member, an outer cylindrical member disposed coaxially with said inner cylindrical member and a roller disposed between said inner and outer cylindrical members, said inner and outer cylindrical members having respective inner and outer grooves facing each other and receiving therein said roller, one of said inner and outer grooves having a radial depth which is close to a diameter of said roller so that said roller is stored substantially fully therein, and said one of inner groove and outer groove being formed radially and circumferentially, a number of one of said inner and outer grooves being larger than a number of the other of said inner and outer grooves and wherein said larger number is an integer multiple of the smaller number.

12. A starter according to claim 11, wherein at least one of said inner and outer cylindrical members is made of resin.

13. A starter according to claim 11 further comprising:

a sun gear formed on said armature shaft;

planetary gears engaged with said sun gear;

an internal gear engaged with said planetary gears and integrally formed with said outer cylindrical member; and

a center bracket coaxially mounted on said output shaft and integrally formed with said inner cylindrical member.