Structure of power transmission apparatus

Patent metadata

Field	Value
Publication number	US-9328806-B2
Application number	US-201414571796-A
Country	US
Kind code	B2
Filing date	Dec 16, 2014
Priority date	Dec 17, 2013
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A power transmission system transmits power from a drive shaft of an internal combustion engine to a first and a second auxiliary device through a belt. An auto-tensioner extends or contracts to change the tension of the belt. A controller rotates the first auxiliary device in a reverse direction to loosen the belt to cause the auto-tensioner to extend to increase the tension of the belt and calculates a reversing timing when the drive shaft will be reversed as a result of increasing of the tension of the belt. The controller inhibits the tensioner body from contracting immediately before or when the reversing time is reached to keep the tension of the belt at an increased degree, thereby eliminating the slippage of the belt on each pulley without having to finely control the operation of the first auxiliary device when the internal combustion engine is started.

First claim

What is claimed is:

1. A power transmission system which works to transmit power, as produced by an internal combustion engine, to a first auxiliary device and a second auxiliary device, the first auxiliary device being operable either in a power mode or in a regenerative mode, comprising:
a driving pulley which is joined to a drive shaft of the internal combustion engine to be rotatable along with rotation of the drive shaft;
a first auxiliary device pulley which is joined to a shaft of the first auxiliary device to be rotatable along with rotation of the shaft of the first auxiliary device;
a second auxiliary device pulley which is joined to a shaft of the second auxiliary device to be rotatable along with rotation of the shaft of the second auxiliary device;
an endless transmitting member which is wound around the driving pulley, the first auxiliary device pulley, and the second auxiliary device pulley;
a tensioner pulley which is rotatable in contact with the endless transmitting member, the tensioner pulley being also movable relative to the internal combustion engine;
an auto-tensioner which is equipped with a tensioner body, the tensioner body working to extend or contract in a given direction to move the tensioner pulley relative to the internal combustion engine, thereby changing a degree of tension of the endless transmitting member;
a biasing mechanism which biases the tensioner body to extend in the given direction;
a stroke inhibitor which works to inhibit the tensioner body from contracting;
a controller which operates in a reverse rotation control mode, a stroke inhibition mode, an engine start mode, and an inhibition releasing mode, the reverse rotation control mode being entered when or after an engine stop condition to stop the internal combustion engine is met to rotate the first auxiliary device in a reverse direction that is opposite a direction in which the first auxiliary device rotates in the power mode, thereby loosening the endless transmission member between the driving pulley and the first auxiliary device pulley to cause the tensioner body to extend in the given direction for increasing the tension of the endless transmitting member, the stroke inhibition mode being to control an operation of the stroke inhibitor to inhibit the tensioner body from contracting, the engine start mode being to operate the first auxiliary device in the power mode to start the internal combustion engine, the inhibition releasing mode being to control the operation of the stroke inhibitor to permit the first auxiliary device to contract, the controller calculating a reversing timing when the drive shaft is expected to start being reversed by an operation of the reverse rotation control mode, the controller controlling the operation of the first auxiliary device based on the reversing timing in the reverse rotation control mode.

2. A power transmission system as set forth in claim 1 , wherein the stroke inhibitor includes a first fluid chamber, a second fluid chamber, a fluid, and a control valve, the first fluid chamber being formed in the tensioner body to have a volume which decreases with contraction of the tensioner body and increases with extension of the tensioner body, the second fluid chamber being formed in the tensioner body in fluid communication with the first fluid chamber, the fluid being within the first fluid chamber and the second fluid chamber, the control valve being driven by the controller to selectively establish and block fluid communication between the first fluid chamber and the second fluid chamber, and wherein in the stroke inhibition mode, the controller controls an operation of the control valve to block the fluid communication between the first fluid chamber and the second fluid chamber, thereby inhibiting the contraction of the tensioner body.

3. A power transmission system as set forth in claim 1 , wherein the controller calculates the reversing timing based on an angular position of the first auxiliary device pulley.

4. A power transmission system as set forth in claim 1 , wherein the controller calculates the reversing timing based on a value derived by integrating a product of an angular velocity of the first auxiliary device pulley and a radius of the first auxiliary device pulley.

5. A power transmission system as set forth in claim 1 , wherein the controller calculates the reversing timing based on an amount of extension of the endless transmitting member.

6. A power transmission system as set forth in claim 5 , wherein when the amount of extension of the endless transmitting member has increased to be greater than equal to a given value in the reverse rotation control mode, the controller stops an operation of the first auxiliary device in the reverse rotation control mode.

7. A power transmissions system as set forth in claim 1 , further comprising a position sensor which measures a position of the tensioner body when extending or contracting, and wherein the controller determines the reversing timing based on the position of the tensioner body, as measured by the position sensor.

8. A power transmissions system as set forth in claim 7 , wherein the controller determines the reversing timing based on an amount of extension of the endless transmitting member and the position of the tensioner body, as measured by the position sensor.

9. A power transmission system as set forth in claim 7 , wherein when the position of the tensioner body, as measured by the position sensor, has reached a given value or more, the controller stops an operation of the first auxiliary device in the reverse rotation control mode.

10. A power transmission system as set forth in claim 1 , wherein in the stroke inhibition mode, the controller inhibits the contraction of the tensioner body and then stops an operation of the first auxiliary device.

11. A power transmission system as set forth in claim 1 , wherein the first tensioner pulley is disposed between the driving pulley and the first auxiliary device pulley or between the driving pulley and the second auxiliary device pulley.

Assignees

• Denso Corp

Inventors

• Noguchi Hitoshi
• Okada Hiroshi
• Oda Shuzo
• Nakano Tomoaki
• Yamashita Yoshihiro
• Yamamoto Yousuke
• Hara Kazuhisa

Classifications

• F16H2007/0885

  the tension being a function of engine running condition · CPC title

• F16H2007/0861

  comprising means for sensing tensioner position · CPC title

• F16H7/1281 Primary

  where the axis of the pulley moves along a substantially circular path · CPC title

• F02N11/04

  the motors being associated with current generators · CPC title

• Y10S903/909

  Gearing · CPC title