Patent GB-435893-A (GB)
Title: Improvements in or relating to the production of application pressures, particularlyfor friction gears
IPC: F16H15/38
Filed: 1934-11-02
Abstract: 435,893. Friction gearing; variablespeed gearing. ERBAN, R., 55, Mariahilferstrasse, Vienna. Nov. 2, 1934, No. 31548. [Class 80 (ii)] In pressure-producing devices of the kind comprising rolling bodies arranged between inclined surfaces of relatively movable members, two or more pressure-producing devices are arranged so that two or more pressure paths occur in parallel between the members to be pressed apart. In the arrangement shown in Figs. 6 and 7, the disc 2 of a tilting roller variable-speed friction gear is driven by a shaft 1 carrying a flange 3, which, through balls 5 in notches 4, 6, exerts axial pressure on the loose ring 7 and thus through a thrust-bearing 8 on the disc 2. The torque also is applied to the ring 7 and is transmitted through a doublysplined collar 9 to a ring 10, which, through balls 13 in notches 11, 12, transmits the torque to the disc 2 and at the same time exerts a further axial pressure on it, the reaction to this pressure being taken up by a thrust bearing 14 between the flange 3 and the ring 10. Three or more radially-spaced sets of balls may be employed. The splined connection between the rings 7, 10 may take the form of balls acting in grooves. The rings 7, 10 may be forced in opposite directions, Fig. 14, by levers 29 passing through slots 28, 28<1> in the rings and engaging notches 28<11> in the member 19 rigid with the driving shaft 1. Alternatively, the lever 29 may be replaced by a toothed sector. To increase the number of pressureapplying devices the race rings may be divided into sectors 30, 31, Fig. 16, the torque passing through these as indicated by the arrow T, each ball 32 producing a pair of axial pressures p. The balls 32 may be replaced by rollers and the device employed for a straight-line motion. In the tilting-roller variable-speed gear shown in Fig. 17, the tubular driving-shaft 45 is splined to a ring 44 connected through pressure-applying balls 42 to the first friction disc 36 and supported by a ball bearing 46 on a flange 47 fixed to a sleeve 39 carrying the second friction disc 37, the second set of pressure-applying balls 49 being arranged to act between the flange 47 and the disc 36 through a ring 60 and thrust bearing 61. The driving torque D1 is transmitted through the balls 42 to the friction disc 36. The torque D2 on the driven disc 37 passes through the loose sleeve 39, the flange 47, and the balls 49 to the ring 60, which is connected with some rotary, and complete axial, freedom to the driven shaft 40 by a loose key 63. To obtain as nearly as possible an axial pressure just sufficient to prevent slip for all positions of the tilting rollers 35, the inclined surfaces 43, 48 of the two pressure-applying devices are made different, so that the total axial thrust in the gear may be represented as k1 D1 + k2 D2, where k1 and k2 are constants. By suitably choosing k1 and k2 the optimum axial pressure may be obtained at any desired point in the scale of velocity-ratios. In the epicyclic gear shown in Figs. 22 and 23, the driving shaft 75 is connected through a pressure device 80 to an intermediate shaft 64, which carries friction discs 65, 66 and a loose intermediate disc 67 which is connected to the disc 65 by a fixed reduction gear 68 and to the disc 66 by an adjustable planetary roller 69 whose carrier 70 is connected to the driven shaft 71. The disc 65 is connected to the intermediate shaft by a pressure device 86. If the torques in the driving-shaft 75, disc 67, and disc 66 are D0, D1 and D2 respectively, and the reduction of the gear 68 is u, then the torque applied to the shaft 64 is (DO+ D2) directly together with uD1 from the disc 65, Fig. 23. Since D2 is formed from D0 + uD1, the total torque is D0 + 2uD1. Hence, to obtain the required axial pressure, the inclined surfaces 85 conveying the torque uD1 are made of half the inclination of the surfaces 78 conveying the torque D0. Alternatively, the disc 66 instead of being fixed to the shaft 64 is connected to it through a separate pressure device 76. An arrangement is described in which the first friction disc of the non-adjustable reduction gear is braked to produce the drive, this friction disc being connected to the final friction disc by an external casing, Figs. 24 and 25 (not shown). A gear is also described of the kind in which two outer friction discs are connected to the driving-shaft and a central disc is driven by a pair of rollers tilted in synchronism in a fixed carrier, Fig. 26 (not shown). Levers may be arranged to multiply the force applied by the pressure devices to the outer discs, Fig. 27 (not shown). In a further form, Fig. 28 (not shown), the central disc drives and the common roller carrier is driven, the driving shaft being connected to the central disc by countershaft gearing, the reaction on which supplies part of the axial pressure. Two further simple friction gears are described, Figs. 29 and 30 (not shown), one of which has a lever device for augmenting the axial pressure.