POWER TRANSFER DEVICE

• US 20090227421A1
• Filed: 03/05/2009
• Published: 09/10/2009
• Est. Priority Date: 03/06/2008
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Fuji Jukogyo KK (Subaru Corp.)
• Inventors: SAITO, Tomohiro
• Granted Patent: US 8,157,703 B2
• Time in Patent Office: Days
• US Class Current: 477/175
• CPC Class Codes: B60K 17/35 including arrangements for suppressing or influencing the power transfer, e.g. viscous clutches differential gearing with locking devices F16H48/20
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2540/103 Accelerator thresholds, e.g. kickdown
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: F16D 2500/10431 4WD Clutch dividing power between the front and the rear axle
• CPC Class Codes: F16D 2500/31 from the vehicle
• CPC Class Codes: F16D 2500/3144 Accelerator pedal position
• CPC Class Codes: F16D 2500/50293 Reduction of vibrations
• CPC Class Codes: F16D 2500/508 Relating driving conditions
• CPC Class Codes: F16D 2500/70426 Clutch slip

Abstract

The object of the present invention is to suppress the generation of abnormal noise from a transmission system that occurs when a vehicle is turning. A front wheel output shaft is directly linked with the transmission system, and a rear wheel output shaft is linked to the transmission system via a transfer clutch. When the front wheel output shaft rpm Nf and the rear wheel output shaft rpm Nr separate from each other beyond a specified value (α2) while turning a corner, and then the accelerator pedal is released and the engine rpm Ne and turbine rpm Nt approach each other beyond a specified value (β2), and then if vibration at a specified vibration frequency appears in the front wheel output shaft rpm Nf (γ2), the duty ratio Rd of the clutch pressure control valve 52 is decreased (δ2). Next, as the duty ratio Rd decreases, when it is determined that vibration in the front wheel output shaft rpm Nf has been eliminated (ε2), normal slip control is restored, and control is performed so that the duty ratio Rd is increased again (ζ2). By doing this, it is possible to suppress vibration of the front wheel output shaft, and thus suppress the generation of abnormal noise from the transmission system.

Claims

1. A power transfer device that distributes a drive force that is output from a transmission system to a main drive wheel and an auxiliary drive wheel, comprising:

a main drive side output shaft that is provided between said transmission system and said main drive wheel, and transmits drive force to said main drive wheel;

an auxiliary drive side output shaft that is provided between said transmission system and said auxiliary drive wheel, and transmits drive force to said auxiliary drive wheel;

a friction clutch mechanism that is provided between said transmission system and said auxiliary drive side output shaft, and controls the drive force that is distributed to said auxiliary drive wheel;

a vibration judgment means for determining a vibration state in said main drive side output shaft based on the rotation state of said main drive side output shaft; and

a clutch control means for decreasing the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft.

2. The power transfer device of claim 1, wherein

said friction clutch mechanism is a hydraulic clutch mechanism, the fastening force of which is regulated by hydraulic oil whose pressure is regulated by a duty control valve;

said vibration judgment means calculates the vibration frequency of said main drive side output shaft based on the rotation state of said main drive side output shaft; and

said clutch control means decreases the fastening force of said friction clutch mechanism when the vibration frequency of said main drive side output shaft converges to a specified range that is set based on the drive frequency of said duty control valve.

3. The power transfer device of claim 1, further comprising:

a main drive side rotation sensor that detects the number of rotations of said main drive side output shaft; and

an auxiliary drive side rotation sensor that detects the number of rotations of said auxiliary drive side rotation sensor;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when the difference in the number of rotations between said main drive side output shaft and said auxiliary drive side output shaft is greater than a specified value.

4. The power transfer device of claim 2, further comprising:

a main drive side rotation sensor that detects the number of rotations of said main drive side output shaft; and

an auxiliary drive side rotation sensor that detects the number of rotations of said auxiliary drive side rotation sensor;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when the difference in the number of rotations between said main drive side output shaft and said auxiliary drive side output shaft is greater than a specified value.

5. The power transfer device of claim 1, further comprising:

a torque converter that is provided between a drive source and said transmission system, and transmits drive force from said drive source to said transmission system;

an input side rotation sensor that detects the number of rotations of the input side of said torque converter; and

an output side rotation sensor that detects the number of rotations of the output side of said torque converter;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when the rotation difference between the number of rotations of said input side and the number of rotations of said output side is less than a specified value.

6. The power transfer device of claim 2, further comprising:

a torque converter that is provided between a drive source and said transmission system, and transmits drive force from said drive source to said transmission system;

an input side rotation sensor that detects the number of rotations of the input side of said torque converter; and

an output side rotation sensor that detects the number of rotations of the output side of said torque converter;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when the rotation difference between the number of rotations of said input side and the number of rotations of said output side is less than a specified value.

7. The power transfer device of claim 3, further comprising:

a torque converter that is provided between a drive source and said transmission system, and transmits drive force from said drive source to said transmission system;

an input side rotation sensor that detects the number of rotations of the input side of said torque converter; and

an output side rotation sensor that detects the number of rotations of the output side of said torque converter;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when the rotation difference between the number of rotations of said input side and the number of rotations of said output side is less than a specified value.

8. The power transfer device of claim 4, further comprising:

a torque converter that is provided between a drive source and said transmission system, and transmits drive force from said drive source to said transmission system;

an input side rotation sensor that detects the number of rotations of the input side of said torque converter; and

an output side rotation sensor that detects the number of rotations of the output side of said torque converter;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when the rotation difference between the number of rotations of said input side and the number of rotations of said output side is less than a specified value.

9. The power transfer device of claim 1, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

10. The power transfer device of claim 2, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

11. The power transfer device of claim 3, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

12. The power transfer device of claim 4, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

13. The power transfer device of claim 5, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

14. The power transfer device of claim 6, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

15. The power transfer device of claim 7, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.

16. The power transfer device of claim 8, further comprising

an acceleration request detection means for detecting an acceleration request from an operator;

wherein

said clutch control means decreases the fastening force of said friction clutch mechanism based on the vibration state of said main drive side output shaft when an acceleration request from an operator is less than a specified value.