US3748924A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic transmission and method of transmitting power therethrough
Assignee: Motors Liquidation Co
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Filing: 1972-04-10
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Granted: 1973-07-31
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Expires: 1992-04-10
Abstract
Abstract A hydrostatic transmission having a variable displacement hydraulic pump in fluid communication with a pair of variable displacement hydraulic motors. The output shafts of the hydraulic motors are drivingly connected respectively to two members of a simple planetary gear set, the third member of which gear set is drivingly connected to the transmission output. One motor shaft and the planetary gear member connected thereto are operatively connected to a brake which is selectively operable to prevent rotation thereof. The brake is engaged in a low speed range to provide a gear reduction between the other motor output shaft and the transmission output through the planetary gear set. The brake is disengaged during a high speed range so that the one motor provides a rotating reaction for the planetary gear set and contributes a speed component to the planetary gear set.
Inventors
- 👤 N Cross
- 👤 J Polak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:17
CPC Classifications
F; F16; F16H; F16H47/00; F16H47/02; F16H47/04; F16H37/00; F16H37/02; F16H37/06; F16H37/08; F16H37/0833; F16H37/084; F16H2037/088; F16H2047/045; F16H3/00; F16H3/44; F16H3/72
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
213 words
A hydrostatic transmission comprising, input means; output means; variable displacement hydraulic pump means drivingly connected with said input means and including means for controlling the displacement thereof; first variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; second variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; gearing means having a first member drive connected with said first motor means, a second member drive connected with said second motor means, and a third member drive connected with said output means; and selectively operable friction brake means operatively connected with said second member to hold said second member and said second motor means stationary for providing a gear reduction drive between said first motor means and said output means in a first speed range while said pump displacement is varied from zero to maximum and the displacement of said first motor means is reduced from maximum to a predetermined value to increase the speed of the output means, and for releasing said second gear member and said second motor means during a second speed range wherein both motor means are proportionately reduced in displacement to increase the speed of the output means.
Claim 2
Dependent Claim
213 words
A hydrostatic transmission comprising, input means; output means; variable displacement hydraulic pump means drivingly connected with said input means and including means for controlling the displacement thereof; first variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; second variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; gearing means having a first member drive connected with said first motor means, a second member drive connected with said second motor means, and a third member drive connected with said output means; and selectively operable friction brake means operatively connected with said second member to hold said second member and said second motor means stationary for providing a gear reduction drive between said first motor means and said output means in a first speed range while said pump displacement is varied from zero to maximum and the displacement of said first motor means is reduced from maximum to a predetermined value to increase the speed of the output means, and for releasing said second gear member and said second motor means during a second speed range wherein both motor means are proportionately reduced in displacement to increase the speed of the output means.
Claim 3
Dependent Claim
223 words
A hydrostatic transmission comprising, input means; output means; variable displacement fluid pump means drivingly connected with said input means; first and second variable displacement fluid motor means in fluid communication with said pump means and each having an output member; planetary gearing means operatively connected between and providing a ratio between said output members, and including a member drivingly connected with said output means; selectively operable brake means operatively connected with said output member of said second pump means; and control means operatively connected with said pump means both said motor means and said brake means for controlling the displacement of said pump means from zero to a maximum value, controlling the displacement of said first motor means from a maximum value to a predetermined value having a displacement ratio with said second motor means equal to ratio in said planetary gearing means after said pump means is at the maximum value, controlling both the displacements of said motor means at a rate maintaining the displacements thereof at a ratio equal to the ratio in said planetary gearing means after said motor means displacement is at the predetermined value, and engaging said brake means while the displacements of said pump means and said first motor means are varied and disengaging said brake means when the displacements of both said motor means are varied.
Claim 4
Dependent Claim
223 words
A hydrostatic transmission comprising, input means; output means; variable displacement fluid pump means drivingly connected with said input means; first and second variable displacement fluid motor means in fluid communication with said pump means and each having an output member; planetary gearing means operatively connected between and providing a ratio between said output members, and including a member drivingly connected with said output means; selectively operable brake means operatively connected with said output member of said second pump means; and control means operatively connected with said pump means both said motor means and said brake means for controlling the displacement of said pump means from zero to a maximum value, controlling the displacement of said first motor means from a maximum value to a predetermined value having a displacement ratio with said second motor means equal to ratio in said planetary gearing means after said pump means is at the maximum value, controlling both the displacements of said motor means at a rate maintaining the displacements thereof at a ratio equal to the ratio in said planetary gearing means after said motor means displacement is at the predetermined value, and engaging said brake means while the displacements of said pump means and said first motor means are varied and disengaging said brake means when the displacements of both said motor means are varied.
Claim 5
Dependent Claim
215 words
A hydrostatic transmission comprising, input means; output means; variable displacement hydraulic pump means drivingly connected with said input means and including means for controlling the displacement thereof; first variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; second variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; simple planetary gearing means having a sun gear drive connected with said first motor means, a ring gear drive connected with said second motor means, and a planet carrier member drive connected with said output means; and selectively operable friction brake means operatively connected with said ring gear to hold said ring gear and said second motor means stationary for providing a gear reduction drive between said first motor means and said output means in a first speed range while said pump displacement is varied from zero to maximum and the displacement of said first motor means is reduced from maximum to a predetermined value to increase the speed of the output means, and for releasing said ring gear and said second motor means during a second speed range wherein both motor means are proportionately reduced in displacement to increase the speed of the output means.
Claim 6
Dependent Claim
215 words
A hydrostatic transmission comprising, input means; output means; variable displacement hydraulic pump means drivingly connected with said input means and including means for controlling the displacement thereof; first variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; second variable displacement hydraulic motor means in fluid communication with said pump means and including means for controlling the displacement thereof; simple planetary gearing means having a sun gear drive connected with said first motor means, a ring gear drive connected with said second motor means, and a planet carrier member drive connected with said output means; and selectively operable friction brake means operatively connected with said ring gear to hold said ring gear and said second motor means stationary for providing a gear reduction drive between said first motor means and said output means in a first speed range while said pump displacement is varied from zero to maximum and the displacement of said first motor means is reduced from maximum to a predetermined value to increase the speed of the output means, and for releasing said ring gear and said second motor means during a second speed range wherein both motor means are proportionately reduced in displacement to increase the speed of the output means.
Claim 7
Dependent Claim
279 words
A hydrostatic transmission comprising, input means; output means; variable displacement fluid pump means drivingly connected with said input means; first and second variable displacement fluid motor means in fluid communication with said pump means and each having an output member; planetary gearing means having a sun gear, ring gear and planet gears operatively connected between and providing a ratio between said output members, and a planet carrier member rotatably mounting said planet gears and being drivingly connected with said output means; first, second and third displacement control means for selectively controlling the displacements of said pump means, said first motor means and said second motor means respectively; selectively operable brake means operatively connected with said ring gear and said output member of said second pump means; and control means operatively connected with said displacement control means and said brake means for varying the displacement of said pump means from zero to a maximum value, decreasing the displacement of said first motor means from a maximum value to a predetermined value having a displacement ratio with said second motor means Equal to ratio of said sun and ring gears in said planetary gearing means after said pump means is at the maximum value, decreasing both the displacements of said motor means at a rate maintaining the displacements thereof at a ratio equal to the ratio of said sun and ring gears in said planetary gearing means after said motor means displacement is at the predetermined value, and engaging said brake means while the displacements of said pump means and said first motor means are varied and disengaging said brake means when the displacements of both said motor means are varied.
Claim 8
Dependent Claim
279 words
A hydrostatic transmission comprising, input means; output means; variable displacement fluid pump means drivingly connected with said input means; first and second variable displacement fluid motor means in fluid communication with said pump means and each having an output member; planetary gearing means having a sun gear, ring gear and planet gears operatively connected between and providing a ratio between said output members, and a planet carrier member rotatably mounting said planet gears and being drivingly connected with said output means; first, second and third displacement control means for selectively controlling the displacements of said pump means, said first motor means and said second motor means respectively; selectively operable brake means operatively connected with said ring gear and said output member of said second pump means; and control means operatively connected with said displacement control means and said brake means for varying the displacement of said pump means from zero to a maximum value, decreasing the displacement of said first motor means from a maximum value to a predetermined value having a displacement ratio with said second motor means Equal to ratio of said sun and ring gears in said planetary gearing means after said pump means is at the maximum value, decreasing both the displacements of said motor means at a rate maintaining the displacements thereof at a ratio equal to the ratio of said sun and ring gears in said planetary gearing means after said motor means displacement is at the predetermined value, and engaging said brake means while the displacements of said pump means and said first motor means are varied and disengaging said brake means when the displacements of both said motor means are varied.
Claim 9
Independent Claim
196 words
A method of transmitting power in a hydrostatic transmission having variable displacement pump means in fluid communication with a pair of variable displacement motor means the output shafts of which are each respectively connected to a member of a planetary gear set the third member of which gear set is connected to the transmission output shaft, and a brake for controlling one member of the planetary gear set and one of the motor output shafts, comprising the steps of: a. engaging the brake to establish a gear reduction between one motor output shaft and the transmission output shaft and to hold the other motor stationary; b. increase the displacement of the pump from zero to maximum thereby driving the one motor; c. decreasing the displacement of the one motor from maximum until the displacement ratio of the motors is equal to the gear ratio between the planetary gear members connected to their output shafts; d. releasing the brake and thereby the other motor shaft; and e. decreasing the displacement of both motors simultaneously while maintaining the ratio of the displacements as established in step (c) until a predetermined minimum displacement is established in the one motor.
Claim 10
Independent Claim
196 words
A method of transmitting power in a hydrostatic transmission having variable displacement pump means in fluid communication with a pair of variable displacement motor means the output shafts of which are each respectively connected to a member of a planetary gear set the third member of which gear set is connected to the transmission output shaft, and a brake for controlling one member of the planetary gear set and one of the motor output shafts, comprising the steps of: a. engaging the brake to establish a gear reduction between one motor output shaft and the transmission output shaft and to hold the other motor stationary; b. increase the displacement of the pump from zero to maximum thereby driving the one motor; c. decreasing the displacement of the one motor from maximum until the displacement ratio of the motors is equal to the gear ratio between the planetary gear members connected to their output shafts; d. releasing the brake and thereby the other motor shaft; and e. decreasing the displacement of both motors simultaneously while maintaining the ratio of the displacements as established in step (c) until a predetermined minimum displacement is established in the one motor.
Claim 11
Independent Claim
203 words
A method of transmitting power in a hydrostatic transmission having variable displacement pump means in fluid communication with a pair of variable displacement motor means the output shafts of which are each respectively connected to the sun and ring gears of a simple planetary gear set the planet carrier members of which gear set is connected to the transmission output shaft, and a brake for controlling the ring gear of the planetary gear set and one of the motor output shafts, comprising the steps of: a. engaging the brake to establish a gear reduction between one motor output shaft and the transmission output shaft and to hold the other motor stationary; b. increase the displacement of the pump from zero to maximum thereby driving the one motor; c. decreasing the displacement of the one motor from maximum until the displacement ratio of the motors is equal to the gear ratio between the sun and ring gears connected to their output shafts; d. releasing the brake and thereby the other motor shaft; and e. decreasing the displacement of both motors simultaneously while maintaining the ratio of the displacements as established in step (c) until a predetermined minimum displacement is established in the one motor.
Claim 12
Independent Claim
203 words
A method of transmitting power in a hydrostatic transmission having variable displacement pump means in fluid communication with a pair of variable displacement motor means the output shafts of which are each respectively connected to the sun and ring gears of a simple planetary gear set the planet carrier members of which gear set is connected to the transmission output shaft, and a brake for controlling the ring gear of the planetary gear set and one of the motor output shafts, comprising the steps of: a. engaging the brake to establish a gear reduction between one motor output shaft and the transmission output shaft and to hold the other motor stationary; b. increase the displacement of the pump from zero to maximum thereby driving the one motor; c. decreasing the displacement of the one motor from maximum until the displacement ratio of the motors is equal to the gear ratio between the sun and ring gears connected to their output shafts; d. releasing the brake and thereby the other motor shaft; and e. decreasing the displacement of both motors simultaneously while maintaining the ratio of the displacements as established in step (c) until a predetermined minimum displacement is established in the one motor.
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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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |