Patent US5649930A successfully refreshed from Google Patents.
US3680652A
Expired / Lapsed
US
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Hydraulic drive for multi-axle vehicles
Assignee: Individual
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Filing: 1971-01-14
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Granted: 1972-08-01
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Expires: 1991-01-14
Abstract
Abstract In a vehicle having driving wheels mounted on different axes and a power plant, the latter is drivingly connected to the input shaft of a differential pump the output shaft of which is mechanically coupled to the driving wheels on one axis, and the driving wheels on the other axis are driven by one or more positive displacement hydraulic motors which receive fluid from the pump. The pump is a positive-displacement pump which has an output shaft rotating at a speed equal to that of the input shaft when the flow of pumped fluid is blocked, the speed decreasing progressively as more fluid is pumped, due to reduced external flow resistance. The two axes may be at the rear of the vehicle or, respectively, at the front and rear. When the hydraulic motors are of effectively variable displacement, the torque on the first-mentioned wheels remains about constant, in relation to that of the differential pump input shaft (except as this can be altered by the interposition of a mechanical gear shift), but that applied to the other wheels decreases as the motor displacement is decreased while the vehicle gains speed; concurrently, the speed of the former wheels increases. Fixeddisplacement hydraulic motors can be used. A by-pass valve across the differential pump, when opened, reduces the torques on all driving wheels essentially to zero.
Inventors
- 👤 Clarence Kirk Greene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:54
CPC Classifications
F; F16; F16H; F16H47/00; F16H47/02; B; B60; B60K; B60K17/00; B60K17/34; B60K17/356; F16H61/00; F16H61/38; F16H61/40; F16H61/42; F16H61/427
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
170 words
In a self-propelled vehicle having a power plant and a plurality of ground-engaging driving means situated on different axes which are displaced along the length of the vehicle, a hydraulic drive system which comprises: a. a differential pump having a power input shaft drivenly connected to said power plant, a positive-displacement pump having a fixed displacement, a high-pressure fluid outlet, a fluid inlet, a pump output shaft, and mechanical reacting means for driving said output shaft at a speed which varies, in relation to the speed of the said input shaft, inversely with the quantity of fluid flowing through said outlet and inlet, b. means mechanically and drivingly connecting said pump output shaft to at least one driving means on one of said axes, and c. a positive-displacement hydraulic motor having fluid intake and discharge openings connected by duct means respectively to said outlet and inlet of the pump, and a motor output shaft which is drivingly connected to at least one driving means on the other of said axes.
Claim 2
Dependent Claim
170 words
In a self-propelled vehicle having a power plant and a plurality of ground-engaging driving means situated on different axes which are displaced along the length of the vehicle, a hydraulic drive system which comprises: a. a differential pump having a power input shaft drivenly connected to said power plant, a positive-displacement pump having a fixed displacement, a high-pressure fluid outlet, a fluid inlet, a pump output shaft, and mechanical reacting means for driving said output shaft at a speed which varies, in relation to the speed of the said input shaft, inversely with the quantity of fluid flowing through said outlet and inlet, b. means mechanically and drivingly connecting said pump output shaft to at least one driving means on one of said axes, and c. a positive-displacement hydraulic motor having fluid intake and discharge openings connected by duct means respectively to said outlet and inlet of the pump, and a motor output shaft which is drivingly connected to at least one driving means on the other of said axes.
Claim 3
Dependent Claim
51 words
In combination with the drive system defined in claim 1, by-pass duct means including a valve interconnecting said outlet and inlet of the pump, whereby the torque applied to both of said driving means can be reduced to substantially zero while the pump input shaft is driven, by opening said valve.
Claim 4
Dependent Claim
32 words
In combination with the drive system defined in claim 1, means for altering the gear ratio between the pump output shaft and said at least one driving means on the first-mentioned axis.
Claim 5
Dependent Claim
97 words
A multi-speed vehicle according to claim 1 having means for blocking the flow of fluid to and from the differential pump, said blocking means being adjustable to active and inacTive conditions, whereby a. at low vehicle speeds the blocking means can be made inactive to cause fluid from the differential pump to drive the hydraulic motor, and b. at high vehicle speeds the blocking means can be made active to transfer power from the pump input shaft substantially completely to the pump output shaft and to apply no driving power from the pump to the hydraulic motor.
Claim 6
Dependent Claim
90 words
The vehicle defined in claim 4 wherein said driving means are wheels, there being at least two wheels on each of said axes situated on opposite sides of the vehicle, said first-mentioned axis is at the front of the vehicle and the other axis is at the rear, said pump output shaft is mechanically connected to drive both wheels at the front of the vehicle, and there is a hydraulic motor for each of the wheels at the rear of the vehicle, the latter wheels being mounted for independent rotation.
Claim 7
Dependent Claim
74 words
The drive system defined in claim 1 wherein said axes are situated at opposite ends of the vehicle, said driving means are wheels, the vehicle includes a pair of wheels mounted for independent rotation of the first of said axes, and the means mechanically and drivingly connecting said pump output shaft comprises a mechanical differential drivingly connected to said wheels, the said pump output shaft being drivingly connected to the input of said differential.
Claim 8
Dependent Claim
66 words
The drive system defined in claim 1 wherein said driving means on the other of said axes includes a pair of wheels mounted for independent rotation and the system includes a pair of hydraulic motors hydraulically connected in parallel to said differential pump, each said motor having a motor output shaft which is drivingly connected to one of the wheels on said other of said axes.
Claim 9
Dependent Claim
36 words
The drive system defined in claim 1 wherein said hydraulic motor has a plurality of cylinders and pistons disposed for reciprocation of the pistons substantially radially from the axis of rotation of said motor output shaft.
Claim 10
Dependent Claim
83 words
The drive system defined in claim 1 wherein said differential pump includes a pump block containing a plurality of pump chambers having axes parallel to the axes of said pump input and output shafts, a swash plate inclined to said axes, and a plurality of pistons situated one within each pump chamber and in thrust relation to the swash plate, said block and swash plate being both rotatable, one fixed to said pump input shaft and the other to said pump output shaft.
Claim 11
Dependent Claim
75 words
A vehicle and drive system as defined in claim 1 wherein the vehicle comprises steerable front wheel means, the said driving means include at least two rotatable wheels mounted for independent rotation at the opposite sides of the vehicle on each of said axes, the wheels on one of said axes being mechanically coupled to said pump output shaft and the wheels on the other of said axes being mechanically coupled to the hydraulic motor.
Claim 12
Dependent Claim
43 words
The vehicle defined in claim 10 wherein said means mechanically and drivingly connecting the pump output shaft comprises a mechanical differential drivingly connected to the wheels on said one axis, the input to the differential gear being coupled to said pump output shaft.
Claim 13
Dependent Claim
44 words
The combination defined in claim 11 which includes a pair of hydraulic motors hydraulically connected in parallel to said differential pump, each said motor having a motor output shaft which is drivingly connected to one of the wheels on the other of said axes.
Claim 14
Dependent Claim
14 words
The combination defined in claim 10 wherein said hydraulic motor is a fixed-displacement motor.
Claim 15
Dependent Claim
58 words
A drive system as defined in claim 1 wherein said axes are situated at opposite ends of the vehicle and said hydraulic motor has means for varying the effective displacement thereof, whereby the torque applied to the last-mentioned driving means can be varied while altering the speed ratio of the pump input shaft to the pump output shaft.
Claim 16
Dependent Claim
65 words
The combination defined in claim 14 wherein said driving means on the first of said axes comprises a pair of wheels mounted on oppoSite sides of the vehicle for independent rotation, and the means mechanically and drivingly connecting said pump output shaft comprises a mechanical differential drivingly connected to said wheels, the said pump output shaft being drivingly connected to the input of said differential.
Claim 17
Dependent Claim
52 words
The combination defined in claim 14 wherein said driving means on the said other axis comprises a pair of wheels mounted on opposite sides of the vehicle for independent rotation and a mechanical differential drivingly connected to said wheels, the motor output shaft being drivingly connected to the input of said differential.
Claim 18
Dependent Claim
77 words
The combination defined in claim 14 wherein said driving means on the said other axis comprises a pair of wheels mounted on opposite sides of the vehicle for independent rotation, there being a pair of positive-displacement motors connected to said differential pump for receiving and returning fluid from and to the pump, and each motor has means for varying the effective displacement thereof, the output shaft of each motor being drivingly connected to one of said wheels.
Claim 19
Dependent Claim
38 words
In combination with the drive system defined in claim 1, gear-reduction means interposed between said hydraulic motor and the drive means driven thereby, whereby said motor can operate at a speed greater than that of said drive means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |