Patent US3897698A successfully refreshed from Google Patents.
US3897698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic control device of transmission
Assignee: KOMATSU SEISAKISHO KK
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Filing: 1973-12-21
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Granted: 1975-08-05
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Expires: 1993-12-21
Abstract
Abstract A hydraulic control device of a power transmission train having a torque converter which is selectively driven either mechanically or hydraulically. The device includes a transmission composed of clutch brakes and gear sets, and has a valve for hydraulically controlling the clutch brakes when the torque converter is driven mechanically. The torque converter is driven hydraulically when the power transmission train is started so that it requires a large driving force and the torque converter is driven mechanically when the power transmission train is driven at high speed to reduce the power loss.
Inventors
- 👤 Takashi Ohsaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:04
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/14; F16H61/143; Y; Y10; Y10T; Y10T74/00; Y10T74/19; Y10T74/19149; Y10T74/19158; Y10T74/19163
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
210 words
In a hydraulic control device of power transmission train having a torque converter selectively driven either mechanically or hydraulically, a transmission comprising a plurality of hydraulically operated clutches and gear sets, a first valve means for controlling the hydraulic pressure of the torque converter and clutches, and a second valve means for selecting the speed in the transmission, the improvement comprising a third valve means for controlling the hydraulic pressure of the clutches by reducing the pressure, said third valve means being positioned in a bypass circuit for shortcircuiting the input side of said second valve means and the drain side of said first valve means, a clutch provided in the torque converter for the mechanical driving of the torque converter, fourth valve means for selecting the mechanical drive, said fourth valve means having a pressure chamber communicating with the pressure chamber of said third valve means and a spring chamber communicating with said clutch, and a solenoid valve for controlling said fourth valve means for switching to the mechanical drive, said solenoid valve being operated by an electric signal, wherein the hydraulic pressure for the clutches when said torque converter is mechanically operated is lower than the hydraulic pressure for the clutches when said torque converter is hydraulically operated.
Claim 2
Dependent Claim
210 words
In a hydraulic control device of power transmission train having a torque converter selectively driven either mechanically or hydraulically, a transmission comprising a plurality of hydraulically operated clutches and gear sets, a first valve means for controlling the hydraulic pressure of the torque converter and clutches, and a second valve means for selecting the speed in the transmission, the improvement comprising a third valve means for controlling the hydraulic pressure of the clutches by reducing the pressure, said third valve means being positioned in a bypass circuit for shortcircuiting the input side of said second valve means and the drain side of said first valve means, a clutch provided in the torque converter for the mechanical driving of the torque converter, fourth valve means for selecting the mechanical drive, said fourth valve means having a pressure chamber communicating with the pressure chamber of said third valve means and a spring chamber communicating with said clutch, and a solenoid valve for controlling said fourth valve means for switching to the mechanical drive, said solenoid valve being operated by an electric signal, wherein the hydraulic pressure for the clutches when said torque converter is mechanically operated is lower than the hydraulic pressure for the clutches when said torque converter is hydraulically operated.
Claim 3
Dependent Claim
61 words
A hydraulic control device as set forth in claim 1, wherein said third valve means comprises a sleeve secured at one end thereof to a valve body, a spool slidably inserted into the valve body, a piston slidably inserted into said sleeve, a load piston slidably inserted into said piston, and a spring for urging said spool toward the load piston.
Claim 4
Dependent Claim
72 words
A hydraulic control device as set forth in claim 2, wherein both a pressure chamber formed by said piston and the valve body and a pressure chamber formed by the load piston and said piston are drained when said torque converter is hydraulically operated, and the hydraulic fluid in both said pressure chambers is urged against the tension of said spring to urge said spool when said torque converter is mechanically operated.
Claim 5
Dependent Claim
52 words
A hydraulic control device as set forth in claim 1, wherein said clutch for the mechanical drive is drained through the spring chamber of said fourth valve means when said torque converter is hydraulically operated, and is operated by the action of the hydraulic pressure when said torque converter is mechanically operated.
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) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |