Continuously variable transmission for vehicle

Patent metadata

Field	Value
Publication number	US-9309970-B2
Application number	US-201514792712-A
Country	US
Kind code	B2
Filing date	Jul 7, 2015
Priority date	Jul 8, 2014
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

The present invention provides a CVT including a transmission mechanism and a planetary gear mechanism which includes a plurality of rotation elements. The transmission mechanism can differentially operate in a predetermined operation mode. The CVT includes a vehicle speed specifying unit for specifying a vehicle speed based on a rotation speed of a rotation member. The unit specifies the vehicle speed from the rotation speed when the rotation speed exceeds a threshold, and specifies the vehicle speed based on a target driving force, a running resistance and a weight of the vehicle when the rotation speed is not more than the threshold.

First claim

What is claimed is:

1. A continuously variable transmission for a vehicle, comprising:
a continuously variable transmission mechanism to which a driving force from a driving source provided in the vehicle is input; and
a planetary gear mechanism including a plurality of rotation elements, the plurality of rotation elements being a sun gear, a ring gear, or a carrier,
wherein the continuously variable transmission is capable of operating in a predetermined operation mode,
in the predetermined operation mode,
the driving force is input to a first rotation element out of said plurality of rotation elements through said continuously variable transmission mechanism,
the driving force is input to a second rotation element out of said plurality of rotation elements without an intervention of said continuously variable transmission mechanism, and
the driving force is output through a third rotation element out of said plurality of rotation elements,
said continuously variable transmission mechanism further comprises:
a target driving force calculation unit configured to calculate a target driving force of the vehicle based on an accelerator opening;
a running resistance calculation unit configured to calculate a running resistance of the vehicle;
a rotation speed detection unit configured to detect a rotation speed of a rotation member provided in the vehicle;
a vehicle speed specifying unit configured to specify a vehicle speed based on a detection result of said rotation speed detection unit; and
a setting unit configured to set a target speed ratio of said continuously variable transmission mechanism based on the vehicle speed specified by said vehicle speed specifying unit and a target rotation speed of the driving source, and
said vehicle speed specifying unit
specifies the vehicle speed from the detection result when the detection result of said rotation speed detection unit exceeds a threshold, and
specifies the vehicle speed based on the target driving force calculated by said target driving force calculation unit, the running resistance calculated by said running resistance calculation unit, and a weight of the vehicle when the detection result of said rotation speed detection unit is not more than the threshold.

2. The continuously variable transmission according to claim 1 , wherein said rotation speed detection unit comprises a pulse sensor configured to detect the rotation speed of an output shaft of the continuously variable transmission for the vehicle, and
a rotation speed serving as the threshold is 0.

3. The continuously variable transmission according to claim 1 , further comprising a slope detection unit configured to detect a grade of a running road of the vehicle,
wherein said running resistance calculation unit calculates, as the running resistance, at least a road grade resistance based on a detection result of said grade detection unit.

4. The continuously variable transmission according to claim 1 , wherein said continuously variable transmission mechanism comprises a toroidal type continuously variable transmission mechanism comprising:
an input-side disc connected to an input shaft;
an output-side disc configured to be rotatable and be coaxial with respect to the input shaft; and
a rolling element configured to frictionally roll between said input-side disc and said output-side disc, and
in the predetermined operation mode,
rotation of an output shaft of the continuously variable transmission for the vehicle can be converted between normal rotation and reverse rotation around a stop state in accordance with a speed ratio of said continuously variable transmission mechanism.

5. The continuously variable transmission according to claim 4 , further comprising:
a first clutch configured to switch between a driving transmission state and a driving transmission cancel state between said output-side disc and said first rotation element; and
a second clutch configured to switch between the driving transmission state and the driving transmission cancel state between said output-side disc and said third rotation element,
wherein the driving force is always input to said second rotation element through the input shaft without the intervention of said continuously variable transmission mechanism, and
in the predetermined operation mode, said first clutch is set in the driving transmission state, and said second clutch is set in the driving transmission cancel state.

Assignees

• Honda Motor Co Ltd

Inventors

• Kamiyamaguchi Tsutomu
• Shinojima Takumi

Classifications

• F16H59/44

  dependent on machine speed {, e.g. the vehicle speed} (F16H59/46 takes precedence) · CPC title

• F16H15/44

  in which two members of non-uniform effective diameter directly co-operate with one another · CPC title

• F16H37/022

  the toothed gearing having orbital motion · CPC title

• F16H61/6646 Primary

  controlling shifting exclusively as a function of speed · CPC title

• F16H37/086

  CVT using two coaxial friction members cooperating with at least one intermediate friction member · CPC title