| 摘要 |
<p>1,140,984. Controlling clutches; variablespeed gearing. DEERE & CO. 7 April, 1967 [8 April, 1966], No. 16013/67. Headings F2D and F2L. The fluid apply pressure of a pedal controlled, e.g. hydraulically applied, clutch at the output side of a variable-speed gear in a motor vehicle, e.g. a tractor, is varied in proportion to the numerical gear ratio (i.e. input to output speed ratio), of the variable-speed gear. As shown, a governed-speed engine 10 drives an infinitelyvariable expanding pulley gear 12 which drives a forward/reverse planetary gear 14, the carrier 44 of which may be clutched to the sun gear 38 by clutch 46 for forward, or braked (not further described), to the casing 50 for reverse. Clutch 46 apply pressure is supplied by a pump P, and modulated by a valve 52 which vents hydraulic pressure between clutch apply line 59 and sump 60. The valve spool 62 is urged to the right by clutch apply pressure fed to the end 72 of the valve via bore 70, and to the left by a compression spring 82 acting between the spool end and a rod 78 connected to the clutch pedal 80, and by feedback pressure 104 in line 102 which includes a restricted orifice 106, the pressure 104 being controlled by a variableorifice valve 88. The spool 96 of valve 88 is positioned by gear lever 32 controlling the gear 12, to vary the orifice 98 and hence vent feedback pressure to sump 94, upshifting the gear increasing the size of orifice 98 to decrease the feedback pressure, and hence lower the clutch apply pressure. Again, Fig. 2 (not shown), clutch apply pressure is vented by variable orifice valve (88a) to a sump directly from the end (72a) of valve (52a), bore (70a) being formed with a restricted orifice (105). The expanding pulley gear may be replaced by a steppedratio gear.</p> |
