US5219038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power transmission device for a four-wheel drive vehicle
Assignee: Honda Motor Co Ltd
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Filing: 1990-11-14
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Granted: 1993-06-15
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Expires: 2010-11-14
Abstract
Abstract A power transmission system for a four-wheel drive vehicle, comprising an engine for directly driving a primary driven axle, and a torque transmission device for transmitting drive torque from the primary driven axle to a secondary driven axle as required, according to a difference in the rotational speed between the front and rear axles, and the torque transmitted between the front and rear axles is reduced for a given difference in the rotational speed between the front and rear axles as a vehicle speed is increased. Thereby, the unnecessary burden of load on the rear axle members is reduced. Preferably, the torque transmission device comprises a structure for limiting the upper limit of the torque which can be transmitted to the secondary driven axle.
Inventors
- 👤 Tetsuro Hamada
- 👤 Kazunori Shibuya
- 👤 Kentaro Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:04
CPC Classifications
B; B60; B60K; B60K17/00; B60K17/34; B60K17/348; B60K17/35; B60K17/3505; B60K23/00; B60K23/08; B60K23/0808
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
193 words
A power transmission system for a four-wheel drive vehicle, comprising: a first member which rotates in synchronism with front wheels; a second member which rotates in synchronism with rear wheels; a power source for directly driving said first member; and torque transmission means interposed between said first and second members for transmitting torque from said first member to said second member at least when a rotational speed of said front wheels is higher than that of said rear wheels by a prescribed value; said torque transmission means comprising a first fluid pressure pump powered by said front wheels, a second fluid pressure pump powered by said rear wheels, a hydraulic clutch interposed between said front and rear wheels, a communication passage connected between an output end of said first fluid pressure pump and an input end of said second fluid pressure pump, and a branch passage connected between said communication passage and a hydraulic actuation chamber of said clutch; said torque transmitted between said members by said torque transmission means for a given difference between the rotational speeds of said front wheels and rear wheels being reduced as a vehicle speed is increased.
Claim 2
Dependent Claim
193 words
A power transmission system for a four-wheel drive vehicle, comprising: a first member which rotates in synchronism with front wheels; a second member which rotates in synchronism with rear wheels; a power source for directly driving said first member; and torque transmission means interposed between said first and second members for transmitting torque from said first member to said second member at least when a rotational speed of said front wheels is higher than that of said rear wheels by a prescribed value; said torque transmission means comprising a first fluid pressure pump powered by said front wheels, a second fluid pressure pump powered by said rear wheels, a hydraulic clutch interposed between said front and rear wheels, a communication passage connected between an output end of said first fluid pressure pump and an input end of said second fluid pressure pump, and a branch passage connected between said communication passage and a hydraulic actuation chamber of said clutch; said torque transmitted between said members by said torque transmission means for a given difference between the rotational speeds of said front wheels and rear wheels being reduced as a vehicle speed is increased.
Claim 3
Dependent Claim
22 words
A power transmission system according to claim 1, wherein said prescribed value increases in proportion to an increase in a vehicle speed.
Claim 4
Dependent Claim
38 words
A power transmission system according to claim 1, wherein a speed ratio of said first fluid pressure pump to said front wheels is smaller than a speed ratio of said second fluid pressure pump to said rear wheels.
Claim 5
Dependent Claim
47 words
A power transmission system according to claim 1, wherein an output of said first fluid pressure pump for a given number of revolution of said front wheels is smaller than an output of said second fluid pressure pump for said number of revolution of said rear wheels.
Claim 6
Dependent Claim
27 words
A power transmission system according to claim 1, further comprising means for limiting a maximum value of torque which may be transmitted by said torque transmission means.
Claim 7
Dependent Claim
42 words
A power transmission system according to claim 1, further comprising a relief valve connected between said branch passage and a pressure sink to restrict the level of fluid pressure in said actuation fluid pressure chamber of said clutch within a prescribed level.
Claim 8
Dependent Claim
197 words
A power transmission system for a four-wheel drive vehicle, comprising: a first member which rotates in synchronism with front wheels; a second member which rotates in synchronism with rear wheels; a power source for directly driving one of said first and second members; and torque transmission means interposed between said first and second members for transmitting torque from said first member to said second member at least when a rotational speed of said front wheels is higher than that of said rear wheels by a prescribed value; said torque transmission means comprising a first fluid pressure pump powered by said front wheels, a second fluid pressure pump powered by said rear wheels, a hydraulic clutch interposed between said front and rear wheels, a communication passage connected between an output end of said first fluid pressure pump and an input end of said second fluid pressure pump, and a branch passage connected between said communication passage and a hydraulic actuation chamber of said clutch; a difference between the rotational speeds of said front wheels and rear wheels required for said torque transmission means to transmit a given magnitude of torque being increased as a vehicle speed is increased.
Claim 9
Dependent Claim
197 words
A power transmission system for a four-wheel drive vehicle, comprising: a first member which rotates in synchronism with front wheels; a second member which rotates in synchronism with rear wheels; a power source for directly driving one of said first and second members; and torque transmission means interposed between said first and second members for transmitting torque from said first member to said second member at least when a rotational speed of said front wheels is higher than that of said rear wheels by a prescribed value; said torque transmission means comprising a first fluid pressure pump powered by said front wheels, a second fluid pressure pump powered by said rear wheels, a hydraulic clutch interposed between said front and rear wheels, a communication passage connected between an output end of said first fluid pressure pump and an input end of said second fluid pressure pump, and a branch passage connected between said communication passage and a hydraulic actuation chamber of said clutch; a difference between the rotational speeds of said front wheels and rear wheels required for said torque transmission means to transmit a given magnitude of torque being increased as a vehicle speed is increased.
Claim 10
Dependent Claim
38 words
A power transmission system according to claim 7, wherein a speed ratio of said first fluid pressure pump to said front wheels is smaller than a speed ratio of said second fluid pressure pump to said rear wheels.
Claim 11
Dependent Claim
47 words
A power transmission system according to claim 7, wherein an output of said first fluid pressure pump for a given number of revolution of said front wheels is smaller than an output of said second fluid pressure pump for said number of revolution of said rear wheels.
Claim 12
Dependent Claim
27 words
A power transmission system according to claim 7, further comprising means for limiting a maximum value of torque which may be transmitted by said torque transmission means.
Claim 13
Dependent Claim
42 words
A power transmission system according to claim 7, further comprising a relief valve connected between said branch passage and a pressure sink to restrict the level of fluid pressure in said actuation fluid pressure chamber of said clutch within a prescribed level.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-14 | 1996-12-14 | 1997-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-14 | 2000-12-14 | 2001-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-14 | 2004-12-14 | 2005-06-15 | $7700.00 | Window Closed / Lapsed |