# US 10,309,532 B2 · Transmission control method of belt type continuously variable transmission

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- Number: US 10,309,532 B2
- Document ID: US10309532B2
- Status: Granted
- Kind: B2
- Application number: 15/807,573
- Filed: 2017-11-09
- Published: 2018-06-14
- Granted: 2019-06-04
- Earliest claimed: 2016-12-09
- Assignees: Honda Motor Co., Ltd.
- Applicants: Honda Motor Co.,Ltd.
- Inventors: Toru Yagasaki
- Web page: https://patentgrep.com/patent/US10309532B2

## CPC

- F16H 61/66272: {characterised by means for controlling the torque transmitting capability of the gearing}
- F16H 9/14: using only one pulley built-up out of adjustable conical parts
- F16H 9/18: only one flange of each pulley being adjustable
- F16H 61/02: characterised by the signals used
- F16H 61/662: with endless flexible members
- F16H 59/70: dependent on the ratio established
- F16H 2059/147: {Transmission input torque, e.g. measured or estimated engine torque}
- F16H 2059/148: {Transmission output torque, e.g. measured or estimated torque at output drive shaft}
- F16H 2059/704: {Monitoring gear ratio in CVT's}
- F16H 2061/66277: {by optimising the clamping force exerted on the endless flexible member}
- F16H: GEARING

## Abstract

In a first process, a tangential friction coefficient of a non-slippage side pulley of a drive pulley and a driven pulley is estimated from a tangential friction coefficient and a winding diameter of a slippage side pulley. In a second process, torque transmitted by a metal belt is calculated from the tangential friction coefficient and the winding diameter. In a third process, a required axial thrust of the non-slippage side pulley is calculated from the torque and the winding diameter. In a fourth process, the gear ratio is changed by reducing a ratio holding axial thrust of the non-slippage side pulley toward the required axial thrust. Therefore, the gear shifting can be performed merely by reducing the axial thrust of the non-slippage side pulley, and thus it is possible to improve the durability of the pulleys or the metal belt and to reduce a load of a hydraulic pump.

## Claims

### Claim 1

A transmission control method of a belt type continuously variable transmission, in which a metal belt (15) is wound on a drive pulley (13) and a driven pulley (14) and a gear ratio is changed by changing axial thrusts of the drive pulley (13) and the driven pulley (14), comprising:
a first process of estimating a relationship between a tangential friction coefficient and a ratio of a non-slippage side pulley according to a relationship between a tangential friction coefficient and a ratio of a slippage side pulley, wherein one of the drive pulley (13) and the driven pulley (14) is the non-slippage side pulley and another one of the drive pulley (13) and the driven pulley (14) is the slippage side pulley,
a second process of calculating transmission torque transmitted by the metal belt (15) from the tangential friction coefficient and a winding diameter of the slippage side pulley,
a third process of calculating a required axial thrust for suppressing slippage of the non-slippage side pulley from the transmission torque and the winding diameter of the non-slippage side pulley, and
a fourth process of changing the gear ratio by reducing a ratio holding axial thrust of the non-slippage side pulley toward the required axial thrust.

### Claim 2 (depends on 1)

The transmission control method according to claim 1, wherein, in a region in which the ratio is a predetermined value or more, reduction control of the axial thrust is performed in the driven pulley (14), and in a region in which the ratio is less than the predetermined value, the reduction control of the axial thrust is performed in the drive pulley (13).