EP0196358B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electrohydraulic control of a spool valve for energizing a heavy duty automatic transmission clutch
Assignee: SPX Technologies Inc
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Filing: 1985-08-16
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Granted: 1990-05-09
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Expires: 2005-08-16
Abstract
No abstract record available.
Inventors
- 👤 John L. Hendrixon
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 08:42
CPC Classifications
F; F16; F16H; F16H59/00; F16H59/02; F16H59/04; F16H59/045; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/042; F15B13/043; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86582; Y10T137/86614
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
223 words
An electrohydraulic control system, especially for transmission clutches, comprising a) a main valve (1) having a body (10), a spool (11), a bore (12), an inlet (16), an outlet (18) and an exhaust port (17), b) an electrohydraulic pulse width modulated pilot valve (13) for providing modulated pressure to shift said spool (11) in opening direction of said main valve (1), c) a feedback means (14) for providing feedback pressure from said outlet (18) to said spool (11) to shift same in closing direction of said main valve (1 characterized in that said pilot valve (13) is a normally closed three-way valve, and said feedback means is a normally closed electrohydraulic three-way on/off valve (14), which can be moved for different modes of operation, namely i) a preparation mode (filling the clutch) wherein the on/off valve (14) is off and the pilot valve (13) is modulated as desired, ii) an operation mode (actuating the clutch) wherein the on/off valve (14) is on and the pilot valve (13) is modulated to obtain a desired increase in outlet pressure, iii) a holding mode (clutch staying activated) wherein the on/off valve (14) is switched off just before the pilot valve (13), and iv) a deactivating mode (de-clutching) wherein the pilot valve (13) is regulated down and then, together with the on/off valve (14), is switched off.
Claim 2
Dependent Claim
223 words
An electrohydraulic control system, especially for transmission clutches, comprising a) a main valve (1) having a body (10), a spool (11), a bore (12), an inlet (16), an outlet (18) and an exhaust port (17), b) an electrohydraulic pulse width modulated pilot valve (13) for providing modulated pressure to shift said spool (11) in opening direction of said main valve (1), c) a feedback means (14) for providing feedback pressure from said outlet (18) to said spool (11) to shift same in closing direction of said main valve (1 characterized in that said pilot valve (13) is a normally closed three-way valve, and said feedback means is a normally closed electrohydraulic three-way on/off valve (14), which can be moved for different modes of operation, namely i) a preparation mode (filling the clutch) wherein the on/off valve (14) is off and the pilot valve (13) is modulated as desired, ii) an operation mode (actuating the clutch) wherein the on/off valve (14) is on and the pilot valve (13) is modulated to obtain a desired increase in outlet pressure, iii) a holding mode (clutch staying activated) wherein the on/off valve (14) is switched off just before the pilot valve (13), and iv) a deactivating mode (de-clutching) wherein the pilot valve (13) is regulated down and then, together with the on/off valve (14), is switched off.
Claim 3
Dependent Claim
73 words
The electrohydraulic control system set forth in claim 1 wherein said main valve (1) further includes d) spring means (19) yieldingly urging said spool (11) in a direction to normally obstruct the path from the inlet (16) to the outlet (18) and to open the path between outlet (18) and exhaust (17), and e) detent means (38, 38a, 39) operable for holding said spool (11) in a detent position in said holding mode.
Claim 4
Dependent Claim
73 words
The electrohydraulic control system set forth in claim 2 wherein said holding mode is obtained by regulating the modulated pressure of said pilot valve (13) to a maximum so as to reach, in the detent position of said spool (11), a balance of forces between modulated pressure on the one side and feedback pressure and spring force on the other side, and then de-energizing both the pilot and the on/off valves (13, 14).
Claim 5
Dependent Claim
60 words
The electrohydraulic control system set forth in claim 1 to 3 wherein said spool (13) of said main valve (1) comprises spaced lands (2, 3), one land (2) being operable to provide metering control of said inlet (16) and the other (3) being operable to control said exhaust port (17), said outlet (18) being positioned intermediate said lands (2, 3).
Claim 6
Dependent Claim
67 words
The electrohydraulic control system set forth in any of claims 1 to 4 wherein said body (10) of said main valve (1) is provided with a first passage (35) providing communication between said inlet (16) and an inlet (24) to said pulse width modulated pilot valve (13) and a second passage (36) providing communication between said outlet (18) and an inlet (29) to said on/off valve (14).
Claim 7
Dependent Claim
47 words
The electrohydraulic control system set forth in any of claims 1 to 5 including a pressure transducer (37) for sensing the fluid pressure in the valve (1) and for signalling lapse of said preparation mode (filled condition of the device to which the fluid is being delivered).
References Cited (Backward Citations)
No citation records indexed.
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