Source: http://www.google.com/patents/US5191915?dq=5,884,272
Timestamp: 2017-10-18 08:37:10
Document Index: 64871190

Matched Legal Cases: ['art 14', 'art 15', 'arts 14', 'arts 14', 'art 15', 'arts 71']

Patent US5191915 - Viscous fluid shear clutches and control valves therefor - Google Patents
A viscous fluid shear clutch comprises a two-part outer casing 14,15 and an inner clutch member 10 between which is defined a clearance gap into which viscous fluid may flow to provide an adjustable degree of coupling between the casing and the clutch members. Fluid is continually pumped out of the gap...http://www.google.com/patents/US5191915?utm_source=gb-gplus-sharePatent US5191915 - Viscous fluid shear clutches and control valves therefor
Publication number US5191915 A
Application number US 07/717,611
Publication number 07717611, 717611, US 5191915 A, US 5191915A, US-A-5191915, US5191915 A, US5191915A
Inventors Arthur E. H. Elmer
Patent Citations (56), Referenced by (7), Classifications (11), Legal Events (6)
US 5191915 A
A viscous fluid shear clutch comprises a two-part outer casing 14,15 and an inner clutch member 10 between which is defined a clearance gap into which viscous fluid may flow to provide an adjustable degree of coupling between the casing and the clutch members. Fluid is continually pumped out of the gap by a circumferential scoop pump. The clutch may be assembled for reverse operation by indexing the casing parts relative to one another. The quantity of fluid in the gap may be controlled dependent on sensed temperature and sensed speed or sensed temperature alone. A thermo pressure valve provides a pressure force related to the sensed temperature; this relationship may be inverse for failsafe operation.
a body defining first, second and third ports;
a shuttle spool means movably mounted in said body;
two spaced flow control zones disposed one intermediate said first and second ports and one intermediate said first and third ports for controlling the flow therebetween;
each flow control zone comprising resilient seal means associated with one of said shuttle spool means and said body for cooperating with seal surface means, the other of said shuttle spool means and said body having seal surface means for cooperating with said resilient seal means, each said resilient seal means preventing the respective cooperating seal surface from moving beyond said resilient seal means, thereby constraining movement of said shuttle spool means with respect to said body so that movement of said shuttle spool means in one sense causes said seal surface means in one flow control zone sealingly to displace the associated resilient seal means and causes the seal surface means in the other flow control zone to lift off the associated resilient seal means to thereby open that flow control zone, whereby movement of said shuttle spool means in one sense causes said first port to be in communication with said second port, and movement in an opposed sense causes said first port to be in communication with said third port;
said control valve modulating an output pressure at said first port, wherein said second port is connected in use to a source of fluid pressure and said third port is connected in use to a vent, and wherein transducer means is provided for moving said shuttle spool means in response to a sensed parameter;
said shuttle spool means including fluid piston means exposed to the output pressure at said first port for urging the shuttle spool means in a first direction tending to allow flow between said first and third ports to vent said output pressure, and a balancing spring urging said shuttle spool means in the opposite direction.
2. A control valve according to claim 1 wherein said transducer means urges or tends to displace said shuttle spool means in said first direction whereby an increase in the output force or displacement of the transducer means reduces the modulated output pressure at said first port.
3. A control valve according to claim 2 including means for adjusting the degree of compression of said balancing spring.
4. A control valve according to claim 1 wherein said transducer means urges or tends to displace said shuttle spool means in a direction opposed to said first direction whereby an increase in the output force or displacement of said transducer means increases the modulated output pressure at said first port.
5. A control valve according to claim 4 including means for adjusting the degree of compression of said balancing spring.
This is a division of application Ser. No. 07/461,535, filed Jan. 5, 1990, now U.S. Pat. No. 5,042,629.
Most known forms of viscous fluid shear clutch employ a scoop pump arrangement in which the scoops face an axial end face of the inner clutch member--so called "side scoop" arrangements. Such arrangements require careful and precise alignment of the scoop and the opposing working face of the clutch member and this can be difficult to achieve and time consuming because of axial float of the shaft. Thus the lowest clearances possible between the scoop and the clutch member still leave significant leakage paths which reduce the efficiency of the scoop pumps. Also, in such arrangements even when the clutch is drained there is still a significant degree of coupling because the scoops are on the side of the clutch member.
Accordingly, in one aspect this invention provides a viscous fluid shear clutch for providing drive between an engine and a cooling fan, said clutch comprising:
an inner clutch member within the casing and spaced therefrom by a clearance gap,
Preferably, said pump means is constituted by a generally plain circumferential wall portion of said inner clutch member and at least one circumferentially extending scoop of limited arcuate extent provided in an opposed cylindrical wall of the casing, each scoop having associated therewith a scoop pump outlet passage arranged adjacent the end region of the scoop which trails in the sense of rotation of the scoop relative to the inner clutch member.
To allow assembly for rotation in either sense, said rotary casing preferably includes one part defining at least a major portion of each scoop and another part defining at least a major portion of each scoop pump outlet passage, the two parts being capable of being assembled in either one of two relative angular positions whereby each scoop pump outlet passage can be located in either end region of the associated scoop depending on the intended sense of rotation of the clutch.
The shuttle spool means is preferably provided at spaced regions with seal surface means engageable in resilient sealing manner with respective valve seats in said valve body and the spacing between said seal surface means may be set as required. Each seal surface means may comprise a resilient `O` ring.
Preferably movement of said shuttle spool means away from said intermediate position causes resilient compression of one of said `O` rings against its valve seat and lifting of the other `O` ring from its valve seat.
In another aspect, this invention provides a valve arrangement including a valve body defining an outlet port and at least two inlet ports each for receiving fluid at respective pressures, a shuttle spool means controlling the flow between said inlet and outlet ports and movable between one position in which one of said outlet ports communicates with said outlet port, and another position in which the other of said ports communicates with said outlet port wherein means are provided for moving said shuttle spool between said aforementioned positions dependent on at least one of said given pressures.
The invention may be performed in various ways and certain embodiments thereof will now be described by way of example only, reference being made to the accompanying drawings, in which:
FIGS. 4a, 4b, and 4c are detail views of three modified control arrangements for a clutch of the general type illustrated in FIG. 1,
Referring to FIGS. 1 to 3, the invention is applied to a viscous fluid clutch of the general type including an internal clutch member or rotor 10 connected to and driven by a coupling 12 attached to an engine shaft (not shown). The rotor is positioned within a two part casing having a front part 14 and a rear part 15. A bearing 16 supports the rear part of the casing off the coupling 12 or shaft. In this example, the casing includes threaded studs 17 which support the blades of a fan (not shown). The rotor 10 has a series of closely spaced annular rings 18 respectively located in a series of grooves 20 in the front and rear parts 14 and 15 of the casing to define a labyrinthine clearance gap of considerably extended area across which torque may be transmitted by viscous shear forces. The amount of torque transmitted may be increased or decreased by increasing (filling) or decreasing (draining) the amount of viscous hydraulic fluid in the gap.
Fluid in the reservoir 22 may drain back to the clearance gap via one or more valve openings (one, 32 shown in the drawings) which is opened or closed by a valve blade 34 forming an extension of a control element 36 pivotted at 38 to the partition wall 24. The control element includes an enlarged portion 40 which acts as a bob weight and is disposed relative to the pivot 38 so that the centrifugal force generated on rotation of the casing tends to urge the control element 36 to close the valve opening 32. Closing movement of the control element 36 is resisted by a compression spring 42 located between the control element 36 and the partition wall 24.
An actuator in the form of a pressure ram assembly 44 despun from the casing by a bearing 46 includes an axially movable ram 48 provided with a despun button 59 engageable with the control element. The pressure ram assembly 44 is supplied with a pressure signal from a thermal pressure valve of the form illustrated in FIG. 5(a) and to be described in detail below. The pressure signal decreases as the sensed temperature increases.
In operation, the pump arrangement 25 continually pump fluid from the clearance gap to the reservoir and flow between the reservoir and the gap is controlled dependent on both the engine coolant liquid temperature and the output speed of the clutch--i.e. the rotational speed of the casing 14,15. Both the speed dependent force and the temperature dependent force act in the same sense, tending to move the control element 36 to close the aperture 32 in the partition wall 24, and these forces are opposed by the spring 42. An increase in the sensed temperature reduces the pressure signal applied to the ram assembly, so the control element 36 tends to open the aperture 32, thus increasing fluid in the clearance gap. Likewise, a reduction in the rotation speed of the casing and thus the fan--reduces the centrifugal force opposing the spring 42, so again tending to open the aperture and increase fluid in the gap.
Referring now to FIGS. 2a,2b and 3, the casing parts 14,15 of the clutch of FIG. 1 are configured so that they can be assembled for engine rotation in either the clockwise sense (FIG. 2a) or anticlockwise sense (FIG. 2b). For proper operation of the scoop pumps, the pump outlet passages or ports 28 must be in the trailing end of the scoops 26, as mentioned above, and so the layout of the scoops 26 and ports 28 must be changed for rotation in the opposite sense. This is achieved in the present arrangement by providing the scoops 26 in the rear casing part 15 and the outlet port and passages in the front casing part and designing the arcuate extent of the scoops and the gaps therebetween in relation to the pitch of the bolts 43 which secure the casing together so that the "handedness" of the clutch can be switched simply by indexing the front and rear casing parts by one bolt spacing.
For ease of assembly during manufacture, the front casing part includes a notch mark 46 and the rear casing part includes the letters `A` and `C` which should be lined up with the mark to denote anticlockwise or clockwise rotation respectively.
FIGS. 4a, 4b and 4c show detail views of three alternative forms of control arrangement for being acted upon by a pressure ram assembly 44 and for controlling the flow through the aperture 32. Each arrangement is similar in some aspects to that of FIG. 1 so common reference numerals have been used where appropriate.
FIG. 4b shows a "closed loop" arrangement in which a thermal pressure valve of the form illustrated in FIG. 5b below provides a temperature dependent force which increases with an increase in temperature. The pressure from the assembly is applied via a common yoke assembly 52, to the ends of two rocking control members 54,56, one of which, the master control member 54 has a valve blade 34 cooperating with the aperture 32. Each of the control members has a bob weight portion 52 which centrifugally generates a force which opposes the temperature dependent force applied by the assembly 44. An increase in sensed temperature or a decrease in the speed of the casing tends to adjust the master control member 49 to increase the fluid in the clearance gap.
The valve of FIG. 5(a) comprises a valve body 66 which defines an inlet 68, an outlet 70, and a vent 72. A shuttle spool 74 is mounted in the body and includes at each end region an `O` ring 75,76 which engages a respective chamfered valve seat 77,78 provided within the valve body. The shuttle pool 74 is made of two parts 71,73 threaded together which allow the spacing between the `O` rings to be adjusted. In use, the valve is adjusted so that, when in the equilibrium or intermediate position of the shuttle spool 74, both `O` rings seal against their valve seats so that there is no communication between any of the inlet 68, outlet 70 and vent 72. Shifting of the shuttle spool 74 to the left, as viewed in FIG. 5a, will compress the `O` ring seal 76 against the valve seat 78, thus maintaining the seal between the inlet 68 and the outlet 70, whilst at the same time lifting the `O` ring 75 off the valve gear 77 so allowing flow between the outlet 70 and the vent 72. Likewise, rightward shifting of the shuttle spool 74 allows flow between the inlet 68 and the outlet 70, whilst preventing flow between the outlet 70 and the vent 72.
At one end, the shuttle spool 74 is connected via a spring to the actuator rod 80 of a thermal sensor 82 such as a wax capsule, which senses the temperature of the engine coolant. The temperature/pressure characteristics of the thermo valve can be biased by turning an adjustable cap 84 which applies an adjustable biass force via a spring 85 to the left hand end of the shuttle spool 74.
FIG. 6 shows schematically a dual temperature thermal pressure valve system which responds to two different temperatures. In the example shown, the valve responds both to the intercooler temperature and to the engine coolant temperature. Both temperatures are sensed by thermopressure valves 90,92 respectively of the form shown in FIG. 5(b)--i.e. which provides an increase in the output pressure as the sensed temperature increases. The temperature modulated pressure signals are supplied to a combiner valve 94 which comprises a body 96 defining left-hand, central and right hand chambers 97,98,99, respectively.
The central chamber 98 includes a shuttle spool 100 with two `O` rings 101,102 which seal against valve seats 103,104 in the valve body when the shuttle spool is in an intermediate position. Each of the other chamber includes a piston 106 having a push rod for engaging the shuttle valve 100. The output pressure signal is taken from the central chamber, between the two valve seats 103,104. The engine coolant modulated pressure signal is supplied to the right hand chamber 99 and the left hand end of the central chamber. The intercooler moderate temperature is supplied to the left hand chamber 97, and the right hand end of the central chamber.
Likewise, in the above examples of thermo-pressure valve, the force signal applied by the wax capsule could be applied by a force transducer and could represent a variable other than sensed temperature. It will be noted that the combination of the thermal sensor 82 and the spring connected to the end of the actuator rod functions as a force transducer applying a variable force to the shuttle spool 74 of magnitude dependent on the sensor temperature.
US283613 * Dec 8, 1882 Aug 21, 1883 Assig-nob op two-thirds to
US2152084 * Jun 5, 1936 Mar 28, 1939 Bendix Prod Corp Brake
US3388694 * May 24, 1966 Jun 18, 1968 Dynair Ltd Adjustable-pitch engine cooling fan and servocontrol mechanism therefor
US3446430 * Jun 12, 1967 May 27, 1969 Dynair Ltd Flexible torsion couplings
US3706325 * May 21, 1971 Dec 19, 1972 Pauliukonis Richard S Simple control valves
US3738571 * May 21, 1971 Jun 12, 1973 Dynair Ltd Wax capsule valves
US3880265 * Jun 25, 1973 Apr 29, 1975 Dynair Ltd Fan drives
US3927830 * Sep 25, 1974 Dec 23, 1975 Borg Warner Control valve
US3960321 * Jan 20, 1975 Jun 1, 1976 Robertshaw Controls Company Temperature responsive valve
US4086989 * Nov 15, 1976 May 2, 1978 Wallace Murray Corporation Temperature controlled hydraulic coupling with moveable dam
US4165035 * Oct 5, 1977 Aug 21, 1979 Eaton Corporation Thermally actuated valve for plural fluid sources
US4285467 * Jul 2, 1979 Aug 25, 1981 Eaton Corporation Three-port thermally responsive valve
US4437554 * Jun 19, 1981 Mar 20, 1984 Household Manufacturing Inc. Fluid shear coupling apparatus
US4488680 * Mar 8, 1983 Dec 18, 1984 Aisin Seiki Kabushiki Kaisha Thermally responsive valve device
US4650045 * Sep 12, 1984 Mar 17, 1987 Sueddeutsche Kuehlerfabrik Julius Fr. Behr Gmbh & Co. Kg Method and apparatus for controlling the output speed of a fluid friction clutch
US4653624 * May 27, 1986 Mar 31, 1987 Household Manufacturing, Inc. Fluid shear coupling apparatus having fluid modulating valve
US4874071 * Aug 12, 1988 Oct 17, 1989 General Motors Corporation Viscous clutch for engine cooling fan
US4967889 * Dec 15, 1988 Nov 6, 1990 Fichtel & Sachs Ag Fluid friction clutch
US4974713 * Aug 25, 1989 Dec 4, 1990 Suddeutsche Kuhlerfabrik Julius Fr. Behr Gmbh & Co. Kg Fluid friction clutch
DE3204554A1 * Feb 10, 1982 Aug 12, 1982 Aisin Seiki Kuehlgeblaeseeinheit fuer eine brennkraftmaschine
EP0055121A1 * Dec 21, 1981 Jun 30, 1982 Household Manufacturing, Inc. Fluid shear coupling apparatus
EP0105647A1 * Sep 13, 1983 Apr 18, 1984 Household Manufacturing, Inc. Fluid shear coupling apparatus
EP0274408A2 * Jan 5, 1988 Jul 13, 1988 Kysor Industrial Corporation Automatic thermal and speed controls for viscous fluid clutches
EP0293102A1 * May 6, 1988 Nov 30, 1988 Eaton Corporation Closed loop pulse modulated viscous fan control
FR2349766A1 * Title not available
FR2550594A1 * Title not available
GB954784A * Title not available
GB1036231A * Title not available
GB1058832A * Title not available
GB1163393A * Title not available
GB1375812A * Title not available
GB1448704A * Title not available
GB1465341A * Title not available
GB1561934A * Title not available
US20150260045 * Oct 8, 2013 Sep 17, 2015 Snecma Propeller comprising a moveable dynamic scoop
CN103339399A * Jan 30, 2012 Oct 2, 2013 博格华纳公司 液体摩擦离合器
CN103339399B * Jan 30, 2012 Mar 16, 2016 博格华纳公司 液体摩擦离合器
U.S. Classification 137/625.27, 251/900, 137/625.5, 236/92.00R, 236/87
Cooperative Classification Y10T137/86686, Y10T137/86895, Y10S251/90, F16D35/021
European Classification F16D35/02B
Owner name: BORGWARNER TURBO SYSTEMS, INC., MICHIGAN
Free format text: CHANGE OF NAME;ASSIGNOR:TRANSPRO GROUP, INC.;REEL/FRAME:011796/0984