Dual cam spring-loaded shifting transmission assembly

Patent metadata

Field	Value
Publication number	US-2018135751-A1
Application number	US-201715808433-A
Country	US
Kind code	A1
Filing date	Nov 9, 2017
Priority date	Nov 11, 2016
Publication date	May 17, 2018
Grant date	—

Abstract

A shifting system is provided that includes at least one shift fork and shift collar. The at least one shift fork is axially movable on a shift rail. The at least one shift fork further has a second end with spaced side walls and a shift fork pin. The shift collar is axially movable on the shift rail between the spaced side walls of the at least one shift fork. The at least one shift collar has a shift collar pin. A biasing member is configured to bias the at least one shift collar against one of the spaced side walls of the at least one shift fork. A rotating shift drum has at least one shift guide profile that receives at least one of the shift fork pin and the shift collar pin to guide the at least one shift fork during a shift of the shifting system.

First claim

1 . A shifting system comprising:
a gear assembly including,
a gear shaft,
at least one gear mounted on the gear shaft, and
at least one shift dog axially movable on the gear shaft while locked to a rotation of the gear shaft, the at least one shift dog configured to selectively lock rotation of the at least one gear to the at least one shift dog;
a shift rail assembly including,
a shift rail,
at least one shift fork axially movable on the shift rail, the at least one shift fork having a first end engaged with the at least one shift dog of the gear assembly, the at least one shift fork further have a second end with spaced side walls and a shift fork pin extending from one of the spaced side walls,
at least one shift collar axially movable on the shift rail between the spaced side walls of the at least one shift fork, the at least one shift collar having a shift collar pin, and
at least one biasing member configured to bias the at least one shift collar against one of the spaced side walls of the at least one shift fork; and
a shift drum assembly configured to rotate during a shift, the shift drum having at least one shift guide profile that receives at least one of the shift fork pin and the shift collar pin to guide the at least one shift fork during a shift of the shifting system.

2 . The shifting system of claim 1 , wherein the second end of the at least one shift fork further has a holding cavity positioned between the spaced side walls, the at least one shift collar received in the cavity.

3 . The shifting system of claim 1 , wherein the at least one biasing member is positioned between the at least one shift collar and another one of the spaced side walls.

4 . The shifting system of claim 1 , wherein the shift drum assembly further comprises:
a shift drum having at least one drum collar including at least one window profile and at least one collar guide profile; at least one shift cam rotationally coupled to the shift drum, the at least one shift cam having a tab received within the window profile of the at least one drum collar, the at least one shift cam further having at least one cam guide profile, the at least one collar guide profile of the at least one drum collar and the at least one cam guide profile forming the at least one shift guide profile; and at least one shift cam biasing member configured and arranged to assert a biasing force between the shift drum and the at least one shift cam.

5 . The shifting system of claim 1 , wherein the at least one shift collar further comprises: first and second opposably extending collar arms that pilot the at least one shift collar on a portion of the shift drum assembly, the shift collar pin positioned between the first and second opposably extending collar arms.

6 . The shifting system of claim 5 , wherein the first and second opposably extending collar arms pilot on at least one shift cam mounted on a shift drum of the shift drum assembly.

7 . The shifting system of claim 1 , further wherein:
the at least one gear includes at least a low gear and a high gear; the at least one shift dog includes at least a first and second shift dog; the at least one shift fork includes at least a first and second shift fork; the at least one shift collar includes at least a first and second shift collar; and the at least one biasing member includes at least a first and second biasing member.

8 . The shifting system of claim 1 , wherein the at least one shift fork, the at least one shift collar and the at least one biasing member are configured and arranged to create a spring in function into the at least one gear and a solid out function out of the at least one gear.

9 . A shifting system comprising:
a shift drum assembly having a plurality of cam tracks; at least one shift dog; at least one gear, the at least one shift dog configured to selectively engage the at least one gear; a shift rail; at least one shift fork having a first end engaged with the at least one shift dog and a second end slidably coupled to the shift rail, the second end of the at least one main shift fork having a shift fork pin received in a first cam track of the plurality of cam tracks of the shift drum assembly; at least one sub-fork further slidably coupled to the shift rail, the at least one sub-fork having a sub-fork pin received in a second cam track of the plurality of cam tracks of the shift drum assembly; and a biasing member for each at least one sub-fork received around the shift rail, the at least one sub-fork and biasing member positioned such that pushing the at least one sub-fork in a first direction causes it to solidly push against a first sidewall of the second end of the at least one shift fork so that the at least one sub-fork moves in concert with the at least one shift fork, the at least one sub-fork and biasing member further positioned such that movement of the at least one sub-fork in a second direction on the shift rail pushes against the biasing member which in turn pushes against a second sidewall of the second end of the at least one shift fork compressing the biasing member to create a preload bias that is used at least in part to pass thru the at least one gear without requiring shift dog teeth of the at least one shift dog and at least one gear to fully mesh.

10 . The shifting system of claim 9 , wherein the second end of the at least one shift fork further has a holding cavity positioned between the spaced first and second sidewalls, the at least one sub-fork received in the cavity.

11 . The shifting system of claim 9 , wherein the shift drum assembly further comprises:
a shift drum having at least one drum collar including at least one window profile and at least one collar guide profile; at least one shift cam rotationally coupled to the shift drum, the at least one shift cam having a tab received within the window profile of the at least one drum collar, the at least one shift cam further having at least one cam guide profile, the at least one collar guide profile of the at least one drum collar and the at least one cam guide profile forming at least part of the plurality of cam tracks; and at least one shift cam biasing member configured and arranged to assert a biasing force between the shift drum and the at least one shift cam.

12 . The shifting system of claim 9 , wherein the at least one sub-fork further comprises: first and second opposably extending collar arms that pilot the at least one sub-fork on a portion of the shift drum assembly, the sub-fork pin positioned between the first and second opposably extending collar arms.

13 . The shifting system of claim 9 , further wherein:
the at least one gear includes at least a low gear and a high gear; the at least one shift dog includes at least a first and second shift dog; the at least one shift fork includes at least a first and second shift fork; the at least one sub-fork includes at least a first and second shift collar; and the at least one biasing member includes at least a first and second biasing member.

14 . The shifting system of claim 9 , wherein the at least one shift fork, the at least one sub-fork and the at least one biasing member are configured and arranged to create a spring in function into the at least one gear and a solid out function out of the at least one gear.

15 . The shifting system of claim, 9 , further comprising:
a detent mechanism configured and arranged to hold at least the shift drum assembly in a preloaded state when a blocked shift occurs.

16 . A vehicle comprising:
a motor to provide motor torque;

Assignees

• Team Ind Inc

Inventors

• Maki Gregory L

Classifications

• F16D23/12

  Mechanical clutch-actuating mechanisms arranged outside the clutch as such (specific for combined clutches F16D21/00; mechanisms specific for synchronisation F16D23/02) · CPC title

• F16H2063/3093

  Final output elements, i.e. the final elements to establish gear ratio, e.g. coupling sleeves or other means establishing coupling to shaft · CPC title

• F16D21/00

  Systems comprising a plurality of actuated clutches (for synchronisation F16D23/04) · CPC title

• F16H63/32

  Gear shift yokes, {e.g. shift forks} · CPC title

• F16H63/24 Primary

  each of the final output mechanisms being moved by only one of the various final actuating mechanisms · CPC title