Friction roller type continuously variable transmission

• US 5,267,920 A
• Filed: 04/21/1992
• Issued: 12/07/1993
• Est. Priority Date: 05/28/1991
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Hibi, Toshifumi
• Primary Examiner(s): Braun, Leslie A.
• Assistant Examiner(s): LAUB, DAVID
• Application Number:
  US07/871,551
• Time in Patent Office: 595 Days
• Field of Search: 74/190, 74/199, 74/200, 74/201, 476/40, 476/42, 476/45
• US Class Current: 476/40
• CPC Class Codes: F16H 15/38 with two members B having hollow toroid surfaces opposite to each other, the member or members A being adjustably mounted between the surfaces

Abstract

A thrust cam device is located at a back side of an input disc to bias the input disc toward an output disc in accordance with a torque applied thereto. The thrust cam device includes a drive cam, a back surface of the input disc, groups of cam rollers each being between respective cam surfaces of the drive cam and input disc, and a cam holder disposed between the drive cam and the input disc for rotatably holding the cam rollers. A disc spring is compressed between the input disc and the drive cam for constantly biasing the input disc toward the output disc. The input disc, the cam holder and the drive cam have respectively positioning holes which can be aligned. The positioning hole of the input disc is threaded. Upon requirement of preassembly of the thrust cam device, the input disc, the cam holder and the drive cam are turned to certain positions wherein the positioning holes are aligned, and a bolt is inserted into the aligned positioning holes and screwed into the threaded positioning hole.

Claims

1. A friction roller type continuously variable transmission comprising:

axially spaced input and output discs, said input disc having a blind threaded hole therein and a first cam surface;

friction rollers each being disposed between respective toroidal surfaces formed on said input and output discs;

a thrust cam device located at a back side of said input disc to bias said input disc toward said output disc in accordance with a torque applied thereto, said thrust cam device including a drive cam having a second cam surface and a first through hole therein, groups of cam rollers each being disposed between the first and second cam surfaces, and a cam holder having a second through hole therein and being disposed between said drive cam and said input disc, said cam holder rotatably holding said groups of cam rollers;

a spring compressed between said input disc and said drive cam for biasing said input disc toward said output disc; and

preassembling means for tightly combining said input disc, said drive cam and said cam holder while compressing said spring, said preassembling means comprising said blind threaded hole, said first through hole, said second through hole, a threaded bolt having an even diameter therethrough except for a threaded end portion, wherein said blind threaded hole, said first through hole and said second through hole are alignable to form a bolt bore when said input disc, said cam holder and said drive cam assume predetermined positions, said threaded bolt being removably received in said bolt bore such that as said threaded bolt is threaded into said blind threaded hole, said input disc, said cam holder and said drive cam are gradually pressed against one another and said spring is gradually compressed; and

positioning means for allowing said input disc and said drive cam to assume the closest positions to each other when said preassembling means gradually presses said input disc, said drive cam and said cam holder while compressing said spring, said positioning means including a first radially extending V-groove on said second cam surface, and a second radially extending V-groove on said first cam surface, wherein said first V-groove and said second V-groove face each other and hold therebetween said friction rollers.

2. A friction roller type continuously variable transmission comprising:

axially spaced input and output discs, said input disc having a blind threaded hole therein and a first cam surface;

friction rollers disposed between respective toroidal surfaces formed on said input and output discs;

a drive cam having a second cam surface and a first through hole therein;

groups of cam rollers disposed between said first and second cam surfaces;

a cam holder disposed between said drive cam and said input disc for rotatably holding said groups of cam rollers, said cam holder having a second through hole therein;

a spring compressed between said input disc and said drive cam for biasing said input disc toward said output disc;

preassembling means including said blind threaded hole, said first through hole, said second through hole, and a threaded bolt having an even diameter therethrough except for a threaded end portion, said blind threaded hole, said first through hole and said second through hole being aligned to form a bolt bore when said input disc, said cam holder and said drive cam assume predetermined angular positions, said threaded bolt being capable of entering said bolt bore such that as said threaded bolt is threaded into said blind threaded hole, said input disc, said cam holder and said drive cam are gradually pressed against one another and said spring is gradually compressed; and

positioning means for allowing said input disc and said drive cam to assume the closest positions to each other when said preassembling means presses said input disc, said drive cam and said cam holder while compressing said spring, said positioning means including a first radially extending V-groove on said second cam surface, and a second radially extending V-groove on said first cam surface, said first V-groove and said second V-groove facing each other and holding therebetween said friction rollers.