Belt type continuously variable transmission for vehicle

• US 4,881,925 A
• Filed: 04/25/1988
• Issued: 11/21/1989
• Est. Priority Date: 04/24/1987
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Hattori, Torao
• Primary Examiner(s): Bui, Thuy M.
• Application Number:
  US07/185,512
• Time in Patent Office: 575 Days
• Field of Search: 474/11, 474/12, 474/17, 474/18, 474/28, 474/69, 474/70, 74/865-14 869
• US Class Current: 474/18
• CPC Class Codes: F16H 61/6625 controlling shifting exclusively as a function of torque
• CPC Class Codes: F16H 61/66263 using only hydraulical and mechanical sensing or control means

Abstract

A hydraulic pressure controller is provided between a hydraulic actuator for changing the effective radii of a drive V-pulley mounted on an input shaft and a driven V-pulley mounted on an output shaft and a hydraulic pump is provided for supplying hydraulic pressure to the hydraulic actuator. The hydraulic pressure controller is controlled by an input torque sensor and a speed change ratio sensor, whereby the hydraulic pressure supplied to the hydraulic actuator is automatically controlled in proportion to the input torque received by the input shaft and the speed change ratio between the input and output shafts.

Claims

1. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, a hydraulic actuator for changing the effective radius of each of said V-pulleys, a hydraulic pressure controller for controlling the hydraulic pressure supplied to said hydraulic actuator, said controller being provided between said hydraulic actuator and a hydraulic pump driven by the engine to supply a hydraulic pressure to said hydraulic actuator, an input torque sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the input torque of said input shaft, a speed change ratio sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the speed change ratio between said input and output shafts, said sensors being connected to said hydraulic pressure controller, wherein said hydraulic pressure controller comprises a regulator valve for permitting and interrupting communication of a working oil passage connecting said hydraulic pump and said hydraulic actuator with a spill oil passage, said regulator valve including a single valve spool and first and second pressure-control springs for biasing said valve spool in a closing direction, said input torque sensor being connected to said first pressure-control spring so as to apply thereto an urging load proportional to said input torque, and said speed change ratio sensor being connected to said second pressure-control spring so as to apply thereto an urging load proportional to said speed change ratio.

2. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, a hydraulic actuator for changing the effective radius of each of said V-pulleys, a hydraulic pressure controller for controlling the hydraulic pressure supplied to said hydraulic actuator, said controller being provided between said hydraulic actuator and a hydraulic pump driven by the engine to supply a hydraulic pressure to said hydraulic actuator, an input torque sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the input torque of said input shaft, a speed change ratio sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the speed change ratio between said input and output shafts, said sensors being connected to said hydraulic pressure controller, wherein said hydraulic actuator includes a hydraulic oil chamber adapted to operate a movable V-pulley half of said driving V-pulley so as to increase the effective radius of said driving V-pulley upon introduction of a hydraulic pressure into said hydraulic oil chamber, said hydraulic oil chamber being connected to said hydraulic pump through a control valve which comprises a main valve member connected to a speed change actuator, and a follower valve member for controlling the introduction of a hydraulic pressure into said hydraulic oil chamber in cooperation with said main valve member to cause the said movable V-pulley half to follow the movement of said main valve member.

4. A belt type continuously variable transmission according to claim 2 or 3, wherein said speed change ratio sensor comprises a rod connected to said second main valve member, so that said speed change ratio is sensed as a displacement of said rod.

3. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, a hydraulic actuator for changing the effective radius of each of said V-pulleys, a hydraulic pressure controller for controlling the hydraulic pressure supplied to said hydraulic actuator, said controller being provided between said hydraulic actuator and a hydraulic pump driven by the engine to supply a hydraulic pressure to said hydraulic actuator, an input torque sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the input torque of said input shaft, a speed change ratio sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the speed change ratio between said input and output shafts, said sensors being connected to said hydraulic pressure controller, wherein said hydraulic actuator includes a hydraulic oil chamber adapted to operate a movable V-pulley half of said driven V-pulley so as to increase the effective radius of said driven V-pulley upon introduction of a hydraulic pressure into said hydraulic oil chamber, said hydraulic oil chamber being connected to said hydraulic pump through a control valve which comprises a main valve member connected to a speed change actuator, and a follower valve member for controlling the introduction of a hydraulic pressure into said hydraulic oil chamber in cooperation with said main valve member to cause the said movable V-pulley half to follow the movement of said main valve member.

5. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, a hydraulic actuator for changing the effective radius of each of said V-pulleys, a hydraulic pressure controller for controlling the hydraulic pressure supplied to said hydraulic actuator, said controller being provided between said hydraulic actuator and a hydraulic pump driven by the engine to supply a hydraulic pressure to said hydraulic actuator, an input torque sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the input torque of said input shaft, a speed change ratio sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the speed change ratio between said input and output shafts, said sensors being connected to said hydraulic pressure controller, wherein said hydraulic actuator includes a first hydraulic oil chamber adapted to operate a movable V-pulley half of said drivin V-pulley so as to increase the effective radius of said drive V-pulley upon introduction of a hydraulic pressure into said first hydraulic oil chamber, and a second hydraulic oil chamber adapted to operate a movable V-pulley half of said driven V-pulley so as to increase the effective radius of said driven V-pulley upon introduction of a hydraulic pressure into said second hydraulic oil chamber, said first hydraulic oil chamber being connected to the hydraulic pump through a first control valve, said second hydraulic oil chamber being connected to the hydraulic pump through a second control valve, said first control valve comprising a first main valve member and a first follower valve member for controlling the introduction of a hydraulic pressure into said first hydraulic oil chamber in cooperation with said first main valve member to cause the movable V-pulley half of said driving V-pulley to follow the movement of said first main valve member, said second control valve comprising a second main valve member and a second follower valve member for controlling the introduction of a hydraulic pressure into said second hydraulic oil chamber in cooperation with said second main valve member to cause the movable V-pulley half of said driven V-pulley to follow the movement of said second main valve member, and said first and second main valve members being operatively connected to a common speed change actuator.

6. A belt type continuously variable transmission according to claim 5, wherein said speed change actuator comprises a hydraulic servo motor which includes a pilot valve operated by a first control force proportional to the vehicle speed and a second control force proportional to the opening degree of a throttle valve of the engine.

7. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, a hydraulic actuator for changing the effective radius of each of said V-pulleys, a hydraulic pressure controller for controlling the hydraulic pressure supplied to said hydraulic actuator, said controller being provided between said hydraulic actuator and a hydraulic pump driven by the engine to supply a hydraulic pressure to said hydraulic actuator, an input torque sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure suppled to said hydraulic actuator is proportional to the input torque of said input shaft, a speed change ratio sensor for controlling said hydraulic pressure controller in such a manner that the hydraulic pressure supplied to said hydraulic actuator is proportional to the speed change ratio between said input and output shafts, said sensors being connected to said hydraulic pressure controller, wherein said input torque sensor comprises a pair of helical gears disposed between said engine and said input shaft to transmit a power from said engine to said input shaft, at least one of said helical gears being axially movable, a spring for resiliently urging said axially movable gear to a direction counter to a thrust force produced at said axially movable gear during transmission of the power, and sensing means for sensing the axial displacement of said gear, so that said input torque is sensed as the axial displacement of said gear.

8. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, an actuator for changing the effective radius of at least one of said V-pulleys, a controller for controlling the hydraulic pressure acting on said actuator, and a hydraulic pump for supplying a pressurized fluid to said actuator, wherein said transmission includes an input torque sensor for controlling said controller in such a manner that the hydraulic pressure acting on said actuator is approximately proportional to the input torque of said input shaft, and a speed change ratio sensor for controlling said controller in such a manner that the hydraulic pressure acting on said actuator is approximately proportional to the speed change ratio between said input and output shafts, said sensors being connected to said controller, and wherein said actuator includes means for supplying a pressurized fluid through a control valve means from the hydraulic pump for changing the effective radius of the V-pulley, said control valve means comprising a main valve member movable in response to a speed change operation and a follower valve member for providing cooperation action between the main valve member and said V-pulley.

9. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft, a drive V-pulley mounted on said input shaft, a driven V-pulley mounted on said output shaft, at least one of said V-pulleys being variable in effective radius, a V-belt stretched around both said pulleys, an actuator for changing the effective radius of at least one said V-pulley and varying the tension applied to the V-belt, a controller for controlling the operation of the actuator, an input torque sensor connected to said controller, a speed change ratio sensor connected to said controller, said controller including mechanical means operated in response to said sensors for causing movement of said mechanical means corresponding to a sum of amounts proportional to both the input torque of said input shaft and the speed change ratio between said input and output shafts as sensed by said sensors for varying the effective radius of at least one pulley having a variable effective radius and the tension in the V-belt.

10. A belt type continuously variable transmission comprising an input shaft driven from an engine, an output shaft for driving a wheel, a drive V-pulley mounted on said input shaft and variable in effective radius, a driven V-pulley mounted on said output shaft and variable in effective radius, a V-belt stretched around both said pulleys, an actuator for changing the effective radius of at least one of the V-pulleys through the medium of a pressurized fluid and varying the tension applied to the V-belt, a control system from controlling the operation of the actuator by adjusting the amount of the pressurized fluid supplied to the actuator, an input torque sensor associated with said control system, a speed change ratio sensor associated with said control system, and said control system including mechanical means interposed in a passage connecting a pressurized fluid source and said actuator and operable to perform mechanical movements of an amount corresponding to a sum of the level of an input torque of said input shaft sensed by the input torque sensor and the level of a speed change ratio between the input and output shafts sensed by the speed change ratio sensor, thereby regulating the level of pressure of pressurized fluid to be fed to the actuator through said passage.

11. A belt type continuously variable transmission according to claim 10, wherein said actuator includes a chamber adapted to be expanded and operate a movable V-pulley half of said one V-pulley so as to increase the effective radius of the pulley upon introduction of the pressurized fluid into said chamber.

12. A belt type continuously variable transmission according to claim 10, wherein said actuator serves to change the effective radii of both said V-pulleys and includes chambers which are adapted to be expanded and operate movable V-pulley halves of the respective V-pulleys so as to increase the effective radii thereof upon introduction of the pressurized fluid into the chambers.

13. A belt type continuously variable transmission according to claim 10, 11, or 12, wherein said control system further includes a servo motor which comprises a pilot valve operated by a firs control force approximately proportional to a vehicle speed and a second control force approximately proportional to the opening degree of a throttle valve of the engine.

14. A belt type continuously variable transmission according to claim 10, 11 or 12, wherein said speed change ratio sensor comprises a rod which performs a displacement in response to a change in the level of said speed change ratio.

15. A belt type continuously variable transmission according to claim 10, wherein said mechanical means comprises a regulator valve for permitting and interrupting communication of said passage with a spill passage, said regulator valve including a single valve spool and first and second pressure-control springs for biasing said valve spool in a closing direction, said input torque sensor being connected to said first pressure-control spring so as to apply thereto an urging load approximately proportional to the level of said input torque, and said speed change ratio sensor being connected to said second pressure-control spring so as to apply thereto an urging load approximately proportional to the level of said speed change ratio.

16. A belt type continuously variable transmission according to claim 15, wherein said single valve spool of the regulator valve has first and second abutment surfaces, one of the abutment surfaces concentrically surrounding the other and receiving thereon one of the pressure-control springs, the other abutment surface receiving thereon the other pressure-control spring.

17. A belt type continuously variable transmission according to claim 10, wherein said input torque sensor comprises a pair of helical gears disposed between said engine and said input shaft to transmit a power from said engine to said input shaft, at least one of said helical gears being axially movable, a spring for resiliently urging said axially movable gear in a direction counter to a thrust force produced at said axially movable gear during transmission of the power, and sensing means for sensing the axial displacement of said gear, so that said input torque is sensed as the axial displacement of said gear.