EP0234136A1
Expired / Lapsed
EP
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Hydromechanical transmission
Assignee: Shimadzu Corp
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Filing: 1986-02-24
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Granted: —
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Expires: 2006-02-24
Abstract
Abstract A hydromechanical transmission that can be used as an efficient continuously variable transmission, having a pair of speed sensors (24a,24b) for detecting the rotational speeds of the transmission ends (18,22) of two mechanical transmission lines (a,b) formed in the transmission, a pair of torque sensors (25a,25b) for detecting the torques transmitted by both said mechanical transmission lines, an actuator (27) connected to one reversible hydraulic pump/motor (7) of a hydraulic power transmission mechanism (8) cooperating with said mechanical transmission lines (a,b) and a computer (28). The computer (28) controls the actuator (27) and two clutches (21,23) in such a way that the system is switched from a low-speed mode to a high-speed mode and vice-versa without producing shock.
Inventors
- 👤 Yasuo Kita
- 👤 Hiroyuki Fujii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 12:48
CPC Classifications
F; F16; F16H; F16H47/00; F16H47/02; F16H47/04; F16H37/00; F16H37/02; F16H37/06; F16H37/08; F16H37/0833; F16H37/084; F16H2037/0866; F16H2037/0873
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
353 words
A hydromechanical transmission comprising : a differential mechanism (4) having first, second, third input/output ends (1,2,3)for forming either a first low-speed mechanical transmission line (a) between the first (1) and second (2) input/output ends or a second high-speed mechanical transmission line (b) between the first (1) and third (3) input/output ends ; a hydraulic power transmission mechanism (8) comprising a pair of hydraulic pump/motor (5,7), one of which acting as a hydraulic pump when the other acts as a hydraulic motor, with the input/output shaft (5a) of one (5) of the pump/motors being connected to the second input/output end of the differential mechanism and the input/output shaft (7a) of the other pump/motor (7) connected to the third input/output end, both pump/motors (5,7) cooperating to constitute continuous variable hydraulic power transmission lines (A,B) ; a first low-speed clutch (21) acting to bring the transmission output end (18) of the first mechanical transmission line (a) into and out of engagement with a common output rotary element (19) ; a second high-speed clutch 23 acting to bring the transmission output end (22) of the second mechanical transmission line (b) into and out of engagement with said common rotary element (19), said second clutch (23) being engaged when the first clutch is disengaged and conversely for selecting either a low-speed mode or a high-speed mode ; characterized in that it further comprises : speed-detection means (24) for detecting the rotational speeds at the transmission output ends (18,22) of the mechanical transmission lines (a,b) ; torque-detection means (25) for detecting the way torque transmission is achieved at said transmission ends (18,22) ; and control means (26) for engaging both the clutches (21,23) when the rotational speeds at both the transmission ends (18,22) that are detected by the speed-detection means (25) become equal, for correcting the change speed ratio of the hydraulic power transmission mechanism (8) until the ways torque transmission is individually achieved by both said transmission output ends (18,22) as detected by the torque detection means are interchanged, and for disengaging the clutch (21;23) through which torque is no longer transmitted when the correction has been completed.
Claim 2
Dependent Claim
353 words
A hydromechanical transmission comprising : a differential mechanism (4) having first, second, third input/output ends (1,2,3)for forming either a first low-speed mechanical transmission line (a) between the first (1) and second (2) input/output ends or a second high-speed mechanical transmission line (b) between the first (1) and third (3) input/output ends ; a hydraulic power transmission mechanism (8) comprising a pair of hydraulic pump/motor (5,7), one of which acting as a hydraulic pump when the other acts as a hydraulic motor, with the input/output shaft (5a) of one (5) of the pump/motors being connected to the second input/output end of the differential mechanism and the input/output shaft (7a) of the other pump/motor (7) connected to the third input/output end, both pump/motors (5,7) cooperating to constitute continuous variable hydraulic power transmission lines (A,B) ; a first low-speed clutch (21) acting to bring the transmission output end (18) of the first mechanical transmission line (a) into and out of engagement with a common output rotary element (19) ; a second high-speed clutch 23 acting to bring the transmission output end (22) of the second mechanical transmission line (b) into and out of engagement with said common rotary element (19), said second clutch (23) being engaged when the first clutch is disengaged and conversely for selecting either a low-speed mode or a high-speed mode ; characterized in that it further comprises : speed-detection means (24) for detecting the rotational speeds at the transmission output ends (18,22) of the mechanical transmission lines (a,b) ; torque-detection means (25) for detecting the way torque transmission is achieved at said transmission ends (18,22) ; and control means (26) for engaging both the clutches (21,23) when the rotational speeds at both the transmission ends (18,22) that are detected by the speed-detection means (25) become equal, for correcting the change speed ratio of the hydraulic power transmission mechanism (8) until the ways torque transmission is individually achieved by both said transmission output ends (18,22) as detected by the torque detection means are interchanged, and for disengaging the clutch (21;23) through which torque is no longer transmitted when the correction has been completed.
Claim 3
Dependent Claim
24 words
A hydromechanical transmission as set forth in claim 1, characterized in that said speed-detection means consists of a pair of rotational-speed sensors (24a, 24b).
Claim 4
Dependent Claim
24 words
A hydromechanical transmission as set forth in claim 1, characterized in that said torque-detection means consists of a pair of pressure sensors (25a, 25b).
Claim 5
Dependent Claim
21 words
A hydromechanical transmission as set forth in claim 1, characterized in that said control means (26) includes an electronic computer (28).
Claim 6
Dependent Claim
21 words
A hydromechanical transmission as set forth in claim 1, characterized in that said control means (26) includes a hydraulic control apparatus.
Claim 7
Dependent Claim
83 words
A hydromechanical transmission as set forth in claim 1, characterized in that said pump/motor (5) being connected to the second input/output end (2) of the differential mechanism is of the fixed displacement type, while the pump/motor (7) being connected to the third input/output end is of the variable displacement type and in that said control means (26) comprises an actuator (27) for varying the displacement of said pump/motor (7) and a computer (28) for controlling the actuator (27) and the two clutches (21,23).
Claim 8
Dependent Claim
31 words
Utilization of a hydromechanical transmission according to any of claims 1 to 6 characterized in that said common output rotary element (19) is used as an input element for the transmission.
Claim 9
Dependent Claim
252 words
Method for transmitting a torque through a hydromechanical transmission comprising between an input shaft (13) and an output shaft (14) : a differential mechanism (4) with at least two alternative mechanical transmission lines (a,b) a hydraulic power transmission mechanism (8) constituted of two reversible hydraulic pump/motors (5,7) hydraulically connected and whose respective shaft (5,7) engage a different said mechanical transmission line (a,b) ; a clutch (21,23) for each of said mechanical transmission line (a,b) for bringing it into and out of engagement with a common input (or output) shaft (19) characterized in that the switching operation from any of said mechanical transmission lines (a) to the other (b) with said common shaft (19) comprises the steps of : modifying the displacement of at least one (7) of said reversible hydraulic pump/motors (5,7) so as to let the rotational speed for both the transmission lines (a,b) in their portion connected to their respective clutchs (21,23) become equal ; detecting the moment when both rotational speeds are equal and engage at this moment the second clutch (23) which was not engaged so far ; detecting the way torque is transmitted selectively by said two lines (a,b) at same moment and modifying the displacement of at least one (7) of said reversible hydraulic pump/motors so as to exactly interchange said respective torque transmission from each line (a,b) to the other (b,a); disengaging the first clutch (21) which was engaged so far as to definitively achieve the switching operation to the second mechanical transmission line (b).
Claim 10
Dependent Claim
252 words
Method for transmitting a torque through a hydromechanical transmission comprising between an input shaft (13) and an output shaft (14) : a differential mechanism (4) with at least two alternative mechanical transmission lines (a,b) a hydraulic power transmission mechanism (8) constituted of two reversible hydraulic pump/motors (5,7) hydraulically connected and whose respective shaft (5,7) engage a different said mechanical transmission line (a,b) ; a clutch (21,23) for each of said mechanical transmission line (a,b) for bringing it into and out of engagement with a common input (or output) shaft (19) characterized in that the switching operation from any of said mechanical transmission lines (a) to the other (b) with said common shaft (19) comprises the steps of : modifying the displacement of at least one (7) of said reversible hydraulic pump/motors (5,7) so as to let the rotational speed for both the transmission lines (a,b) in their portion connected to their respective clutchs (21,23) become equal ; detecting the moment when both rotational speeds are equal and engage at this moment the second clutch (23) which was not engaged so far ; detecting the way torque is transmitted selectively by said two lines (a,b) at same moment and modifying the displacement of at least one (7) of said reversible hydraulic pump/motors so as to exactly interchange said respective torque transmission from each line (a,b) to the other (b,a); disengaging the first clutch (21) which was engaged so far as to definitively achieve the switching operation to the second mechanical transmission line (b).
References Cited (Backward Citations)
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