Torque responsive rotation control device

• US 5,931,272 A
• Filed: 04/29/1998
• Issued: 08/03/1999
• Est. Priority Date: 05/02/1997
• Status: Expired due to Fees

• Current Assignee: NTN Corporation
• Original Assignee: NTN Corporation
• Inventors: Fukushima, Shigeaki, Kawase, Tatsuo
• Primary Examiner(s): Lorence, Richard M.
• Application Number:
  US09/069,286
• Time in Patent Office: 461 Days
• Field of Search: 192/54.52, 192/55.1, 192/56.62, 192/89.21, 192/93 A, 464/35, 464/36
• US Class Current: 192/54.52
• CPC Class Codes: F16D 7/06 with intermediate balls or rollers

Abstract

An input-side rotary member 20, including an input gear 7, and an output-side rotary member 19, including a torque cam 1 fixedly mounted on an output shaft 12, are provided on the same axis of rotation. The input-side rotary member 20 is provided with an input cage 3 having a plurality of radially extending pockets 30 and balls 9 movably accommodated within the respective pockets 30. The torque cam 1 is provided with a generally annular cam groove 31 in which the balls 9 move rollingly, which groove 31 is of a shape having a distance from the axis of rotation that varies continuously. A presser member 2 is provided with a pressing face 2a by which the balls 9 are urged by a spring element 4. In this way, the input rotation of, for example, an engine can be reduced and then transmitted to a driven device such as an engine auxiliary equipment 102 with respect to the boundary set by a preset torque value.

Claims

1. A torque responsive rotation control device which comprises:

an input-side rotary member and an output-side rotary member rotatable about a common axis and independent from each other;

a cage having a plurality of pockets defined therein so as to extend radially and including balls movably accommodated within the corresponding pockets, said cage being provided on one of the input-side and output-side rotary members;

the other of said input-side and output-side rotary members having a generally annular cam groove defined therein in coaxial relation to said common axis, said cam groove being shaped to have a distance from said common axis varying continuously;

a presser member movable in an axial direction and having a pressing face defined therein in coaxial relation to an axis of rotation thereof and inclined against the axis, said presser member being axially displaceably provided with said pressing face confronting said cam groove in said other of the input-side and output-side rotary members; and

an elastic element applying a pressing force to the presser member to cause the pressing face to urge the balls towards said one of the input-side and output-side rotary members.

2. The torque responsive rotation control device as claimed in claim 1, wherein said cam groove is of a shape having the distance from said common axis that varies in a fashion similar to a generally sinusoidal wave, and wherein the pockets in said cage is equal in number to the number of dales of the sinusoidal wave occurring in one complete circumference of the cam groove and are equidistantly spaced from each other.

3. The torque responsive rotation control device as claimed in claim 1, further comprising an input gear;

an input stand-by gear provided on an output shaft of the output-side rotary member through a one-way clutch for rotation in one direction; and

first and second engine-side gears engageable with the input gear and the input stand-by gear, respectively, said first and second engine-side gears being mounted on a common drive shaft, and wherein a relation among respective numbers of teeth of the various gears being so chosen that only when the number or revolutions of the input stand-by gear exceeds the number of revolution of the output shaft, rotation can be transmitted from the second engine-side gear to the output shaft through the input stand-by gear and the one-way clutch.

4. The torque responsive rotation control device as claimed in claim 1, further comprising a support cylinder fitted over an outer periphery of the presser member and defining an oil chamber for applying a hydraulic pressure to the presser member in an axial direction, and an oil passage for supplying oil to the oil chamber, a discharge passage defined between the outer periphery of the presser member and an inner surface of the support cylinder engaging the outer periphery of the presser member, and wherein said oil chamber, said oil passage and said discharge passage altogether define a dumper.

5. The torque responsive rotation control device as claimed in claim 1, wherein said output-side rotary member comprises a torque cam having the cam groove defined therein and rotatable together with an output shaft, and said input-side rotary member being constituted by an input gear, rotatably mounted on an outer periphery of the torque cam through a rolling contact bearing and the cage fitted to this input gear, and wherein said presser member is supported by the output shaft for displacement axially of the output shaft through a mechanical rolling contact element.

6. The torque responsive rotation control device as claimed in claim 1, wherein said output-side rotary member comprises a torque cam having the cam groove defined therein and rotatable together with an output shaft, and said input-side rotary member being constituted by an input gear, rotatably mounted on an outer periphery of the torque cam through a rolling contact bearing and the cage fitted to this input gear;

further comprising an elastic element support member for supporting the elastic element being provided on the output shaft; and

a bearing interposed between the elastic element support member and the output shaft for permitting a relative rotation between the elastic element support member and the output shaft.