Control apparatus for limited-slip differential for front and rear wheels of vehicle

• US 10,434,875 B2
• Filed: 04/02/2018
• Issued: 10/08/2019
• Est. Priority Date: 04/06/2017
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Subaru Corp.
• Inventors: Tsuji, Taichi
• Primary Examiner(s): Holmes, Justin
• Application Number:
  US15/943,110
• Publication Number:
  US 20180290540A1
• Time in Patent Office: 554 Days
• Field of Search: None
• CPC Class Codes: B60K 17/3462 with means for changing distribution of torque between front and rear wheels
• CPC Class Codes: B60K 2023/043 Control means for varying left-right torque distribution, e.g. torque vectoring
• CPC Class Codes: B60K 2023/0841 for locking a central differential, e.g. by using a lock-up clutch
• CPC Class Codes: B60K 23/04 for differential gearing
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: F16H 2048/204 Control of arrangements for suppressing differential actions
• CPC Class Codes: F16H 2048/205 using the steering as a control parameter
• CPC Class Codes: F16H 2048/207 using torque sensors
• CPC Class Codes: F16H 48/20 Arrangements for suppressing or influencing the differential action, e.g. locking devices
• CPC Class Codes: F16H 48/22 using friction clutches or brakes
• CPC Class Codes: F16H 48/34 using electromagnetic or electric actuators

Abstract

A control apparatus for a limited-slip differential for front and rear wheels of a vehicle, the control apparatus includes: a basic LSD torque calculation module configured to calculate a basic LSD torque at least on the basis of a transfer input torque; a subtraction LSD torque calculation module configured to calculate a subtraction LSD torque that is subtracted from the basic LSD torque at least on the basis of a vehicle speed and a steering angle; a minimum LSD torque calculation module configured to calculate a minimum LSD torque on the basis of the transfer input torque; a target LSD torque setting module configured to set a target LSD torque at least on the basis of the basic, subtraction, and minimum LSD torques; and a clutch control module configured to control an engaging force of a clutch.

Claims

1. A control apparatus for a limited-slip differential for front and rear wheels of a vehicle, the control apparatus comprising:

a basic LSD torque calculation module configured to calculate a basic LSD torque at least on a basis of a transfer input torque;

a subtraction LSD torque calculation module configured to calculate a subtraction LSD torque that is subtracted from the basic LSD torque at least on a basis of a vehicle speed and a steering angle;

a minimum LSD torque calculation module configured to calculate a minimum LSD torque on the basis of the transfer input torque;

a target LSD torque setting module configured to set a target LSD torque at least on a basis of the basic LSD torque, the subtraction LSD torque, and the minimum LSD torque; and

a clutch control module configured to control an engaging force of a clutch configured to freely limit a differential of the front and rear wheels in accordance with the engaging force on a basis of the target LSD torque.

2. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 1, wherein the target LSD torque setting module sets the basic LSD torque as the target LSD torque in a case in which the basic LSD torque is smaller than the minimum LSD torque.

3. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 1, wherein the target LSD torque setting module sets, as the target LSD torque, a value obtained by subtracting the subtraction LSD torque from the basic LSD torque in a case in which the basic LSD torque is larger than or equal to the minimum LSD torque.

4. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 2, wherein the target LSD torque setting module sets, as the target LSD torque, a value obtained by subtracting the subtraction LSD torque from the basic LSD torque in a case in which the basic LSD torque is larger than or equal to the minimum LSD torque.

5. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 1, wherein the target LSD torque setting module sets the minimum LSD torque as the target LSD torque in a case in which the basic LSD torque is larger than or equal to the minimum LSD torque.

6. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 2, wherein the target LSD torque setting module sets the minimum LSD torque as the target LSD torque in a case in which the basic LSD torque is larger than or equal to the minimum LSD torque.

7. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 3, wherein the target LSD torque setting module sets the minimum LSD torque as the target LSD torque in a case in which the basic LSD torque is larger than or equal to the minimum LSD torque.

8. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 4, wherein the target LSD torque setting module sets the minimum LSD torque as the target LSD torque in a case in which the basic LSD torque is larger than or equal to the minimum LSD torque.

9. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 1, wherein the minimum LSD torque calculation module calculates the minimum LSD torque on the basis of the basic LSD torque calculated by the basic LSD torque calculation module.

10. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 2, wherein the minimum LSD torque calculation module calculates the minimum LSD torque on the basis of the basic LSD torque calculated by the basic LSD torque calculation module.

11. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 3, wherein the minimum LSD torque calculation module calculates the minimum LSD torque on the basis of the basic LSD torque calculated by the basic LSD torque calculation module.

12. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 4, wherein the minimum LSD torque calculation module calculates the minimum LSD torque on the basis of the basic LSD torque calculated by the basic LSD torque calculation module.

13. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 9, wherein the minimum LSD torque calculation module sets, as the minimum LSD torque, a value obtained by multiplying the basic LSD torque, which is calculated by the basic LSD torque calculation module, by a predetermined ratio.

14. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 10, wherein the minimum LSD torque calculation module sets, as the minimum LSD torque, a value obtained by multiplying the basic LSD torque, which is calculated by the basic LSD torque calculation module, by a predetermined ratio.

15. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 11, wherein the minimum LSD torque calculation module sets, as the minimum LSD torque, a value obtained by multiplying the basic LSD torque, which is calculated by the basic LSD torque calculation module, by a predetermined ratio.

16. The control apparatus for a limited-slip differential for front and rear wheels of a vehicle according to claim 12, wherein the minimum LSD torque calculation module sets, as the minimum LSD torque, a value obtained by multiplying the basic LSD torque, which is calculated by the basic LSD torque calculation module, by a predetermined ratio.

17. A control apparatus for a limited-slip differential for front and rear wheels of a vehicle, the control apparatus comprising

circuitry configured to

calculate a basic LSD torque at least on a basis of a transfer input torque,

calculate a subtraction LSD torque that is subtracted from the basic LSD torque at least on a basis of a vehicle speed and a steering angle,

calculate a minimum LSD torque on the basis of the transfer input torque,

set a target LSD torque at least on a basis of the basic LSD torque, the subtraction LSD torque, and the minimum LSD torque, and

control an engaging force of a clutch configured to freely limit a differential of the front and rear wheels in accordance with the engaging force on a basis of the target LSD torque.