192 clutches and power-stop control – Clutches – Fluent material
Patent
1993-12-16
1997-02-04
Pitts, Andrea L.
192 clutches and power-stop control
Clutches
Fluent material
188316, 188317, 464 24, F16D 2506
Patent
active
055989110
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to variable torque-speed transmission couplings and in particular to a hydraulic slider coupling.
The invention has been developed primarily for use in automotive applications and will be described with reference to this application, However, it will be appreciated that the invention is not limited to this particular field of use.
BACKGROUND ART
A viscous coupling is a torque transmitting element which functions by means of viscous friction whereby the torque-speed characteristic is dependent upon the rheological properties of the viscous filling medium which is usually a silicone based fluid.
In the past, viscous couplings have usually comprised sets of mutually interleaved parallel annular plates coaxially mounted for rotation within an hermetically sealed enclosure containing a viscous medium in contact with adjacent surfaces of the plates. Alternate plates are connected with respective driving and driven elements such that an angular velocity differential across the coupling causes viscous shearing of the fluid in the annular clearance between adjacent plates to produce the desired speed-torque transmission characteristic. Commonly used silicon based fluids in viscous couplings exhibit a degressive torque response with increasing rate of shear.
It is also known to provide means whereby the plates can be urged into frictional engagement under predetermined operating conditions to increase torque transmission and to provide a series of radially spaced perforations in the plates to permit predetermined variation of the torque transmission characteristics of the coupling to suit particular applications.
However, these viscous couplings of the prior art are relatively slow to transfer torque and do not provide great design flexibility, particularly in applications requiring the transmission of large torques. Furthermore, known viscous couplings are usually highly sensitive to variations in operating conditions such as temperature and fluid viscosity and pressure.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a relatively simple and compact coupling which ameliorates the abovementioned disadvantages of the prior art, or at least provides an alternative to known viscous couplings.
According to a first aspect, the invention consists in a coupling assembly comprising a first member and a second member disposed for relative rotational engagement, one of said first and said second members including a circumferentially extending continuous and generally sinuate track, the other of said first and said second members including at least one transverse track extending in a direction substantially normal to the general direction of the sinuate track, a slider located in an intersecting region of said sinuate and transverse tracks such that relative rotation of said first and said second members causes said slider to oscillate axially within said transverse track while traversing said sinuate track, and a hydraulic fluid medium within said transverse track to provide a resistance to said oscillation of said slider.
Preferably the first member is an inner hub including the sinuate track on an outer cylindrical surface thereof and the second member is a complementary outer hub supported for coaxial rotation with respect to the inner hub and defining a plurality of uniformly spaced axially extending transverse tracks in the form of grooves on an inner cylindrical surface thereof, the inner hub being mounted for relative rotation substantially within the outer hub.
Preferably, the sinuate track is periodic and in one form of the invention the track is sinusoidal.
In a first preferred form of the invention, the slider is in the form of a ball and the track and grooves are substantially semicircular in cross section.
However, in an alternative form of the invention each ball engages a prismatic slider for reciprocation within a complementary prismatic groove or bore. The prismatic grooves are preferably rectangular in cross section.
In a fu
REFERENCES:
patent: 2118808 (1938-05-01), Corbin, Jr.
patent: 3319754 (1967-05-01), Kokochak et al.
patent: 4889206 (1989-12-01), Wiese et al.
patent: 5103642 (1992-04-01), Suzuki et al.
Abstract, "Vehicle friction coupling system--has higher transmission capacity in forward than in reverse direction," Viscodrive GmbH Nov. 8, 1987--DE-726641.
SAE paper entitled, "SAE Exhibition, Featured Japanese Auto Technologies and Products from SAE--Part I," dated Apr. 19, 1990, p. 24, with one page drawing of Fuji/Nissan differential (description in Italian, date unknown).
Reg Technologies Inc. press release, entitled "Re: Rand Cam/Direct Charge Engine," dated Jul. 26, 1993, 5 pages.
SAE Technical Paper Series No. 920611, entitled "Viscous Couplings in 4WD Vehicles: Application of Computational Modelling," International Congress & Exposition, Detroit, Michigan, Feb. 24-28, 1992, pp. 37-46.
JSAE paper, entitled "New Technologies & New Cars, Hydraulic Coupling Unit (HCU) for Full-Time 4WD Vehicles," JSAE Review, vol. 11, No. 4, Oct. 1990, pp. 100-105.
IMechE paper No. C377/88, entitled "Application of viscous couplings for traction control in passenger cars," IMechE 1988 C277/88, pp. 151-161.
SAE International SP-854, entitled "Automotive Transmission Advancements, Development of a Rotary Tri-Blade Coupling for Four-Wheel Drive Cars," No. 910806, pp. 157-163 (date unknown).
Japan Autotech Report article, entitled "Drivetrain, Mitsubishi Hydraulic Coupling Unit," May 1989, pp. 17-23.
Joachim Clifford A.
Spryszynski Stanislaw
BTR Engineering (Australia) Limited
Pitts Andrea L.
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