Ratio sensitive control for limited slip differentials

• Main Authors: COSTA PHILIP J, JR. JOHN H. BABBITT, BOWEN HARRY H
• Format: Patent
• Language: English
• Published: 30.06.1964
• Subjects: BLASTING; BRAKES; CLUTCHES; COUPLINGS FOR TRANSMITTING ROTATION; ENGINEERING ELEMENTS AND UNITS; GEARING; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; LIGHTING; MECHANICAL ENGINEERING; THERMAL INSULATION IN GENERAL; WEAPONS

993,857. Differential gears. CATERPILLAR TRACTOR CO. March 5, 1962 [April 5, 1961], No. 8346/62. Heading F2D. [Also in Divisions G1 and H3] A system for controlling slip of a pair of wheels driven through differential gearing includes means for sensing the speed of each wheel and means operable automatically upon the speed of either wheel exceeding that of the other by more than an amount dependent upon the wheel speeds to actuate means for limiting differential action. Carrier member 12 is driven through ring gear 11 by bevel gear 18. Member 12 has a plurality of differential pinions journalled in a spider 30 and engaging with bevelled side gears 24, 26 on axle shafts 20, 22. A multiple disc clutch 32 has alternate discs secured to member 12 and the remaining discs secured to a hub 34 connected to gear 24. Hydraulic fluid is supplied through line 40 and fluid-conducting ring 41 to cavity 38 containing an annular piston 36. Proximity pick-ups 49, 50 adjacent toothed shaft portions 53, 54 provide output signals indicative of the shaft speeds. These signals are squared at 60, 61 and applied to integrating transistors 63 having feedsack resistors 64, 66 and capacitors 67. Capacitors 67 render the feedstack signal frequency-dependent, so that the output of each transistor is an inverse function of the speed of one of the shafts 20, 22. The outputs are applied through voltage doublers 71, 72, 73, 74 to a detector 75. When the difference between the outputs reaches a predetermined value a relay 76 actuates the solenoid 58 of valve 59. Capacitors may be provided between the base of each transistor and common line 68 to ensure linearity at high wheel speeds. Resistors 69 may be replaced by a pair of parallel-connected potentiometers to permit matching of the transistor outputs at low and high frequencies.