Patent GB-494571-A (GB)
Title: Improvements in and relating to torque transmitting mechanism
IPC: F16H61/50
Filed: 1937-02-23
Abstract: 494,571. Hydraulic power transmitters; reversing-gearing; clutches. HEPPNER, F. A. M. Feb. 23, 1937, Nos. 5432 and 22113. [Class 69 (ii)] [Also in Group XXIV] In a hydraulic gear comprising a pump member, a turbine member and a reaction member coacting in a working circuit of toroidal form, the reaction member comprises fixed as well as rotatable blade rows. This arrangement is stated to provide an overdrive. One form, applicable to motor road vehicles, comprises pump blades 3, Fig. 1 (Comp), turbine blades 10, fixed reaction blades 17 carried by a wheel 14 splined to a shaft 11 fixed to the stationary casing 9, and blades 16 carried by a wheel 13, a free-wheel device 15 being provided between the wheels 14 and 13, permitting forward rotation of the latter and preventing backward rotation thereof. The free-wheel comprises, Fig. 3 (Comp.), rollers 37 interposed between fixed projections 40 of the stationary wheel 14 and engaging on the one hand the hub 38 of the wheel 13 and on the other hand notches 35 in a floating ring 36 which is under spring restraint. All the blades are of thick streamline section with well-rounded entry ends; the blades 16 are set substantially radial, while the blades 17 are set to impart to the liquid a component of velocity in the direction of rotation of the impeller. The angle of the blades 17 may be externally adjustable during running. The blades as seen in side view in Fig. 1 (Comp.) may, instead of having straight leading edges, have concave leading edges ; additional blades 3a may be provided as shown in Fig. 5 (Comp.). Bearings 4, 7, 8, 12, 19 are provided ; labyrinth seals 21, 22, 23 and rubbing seals 24, 25 are provided. Leakage collecting in the sump 28 is returned to the working circuit by centrifugal passages 20 in the impeller 2, co-operating with passages 34 in the stationary wheel 14, these latter passages constituting the stationary outlet blading of the auxiliary centrifugal pump. Bores 32 in the blades 17 permit air venting ; a bore 33 in the wheel 13 permits the return to the working circuit of liquid escaping past the labyrinth 22. Reverse gear is provided. For forward drive, teeth on a muff 47 engage teeth 45 on the turbine shaft 6 and teeth 46 on the output shaft 18, giving a positive drive. For reverse drive, teeth 54 are engaged with fixed teeth 55 so as to lock a planet carrier 53 against rotation, the planets 49 meshing with the teeth 45 and with teeth 48 on the muff 47, the other teeth which now mesh only with the teeth 46, giving a geared reverse. The parts may be so arranged that when a change is made from forward to reverse an intermediate position is passed through in which the teeth 54, 55 come into mesh before the muff. is clear of teeth 45 ; in such position the gear is locked, and if it is provided changes from forward to reverse or vice versa must only be made when the secondary and tail shafts are stationary. Instead, there may be a neutral free position between forward and reverse gears in which case synchronizing means of known kind, for example bevelled faces on the teeth coming into engagement are preferably provided to hinder crashing of the gear. A modification, Fig. 6 (Comp.) (not shown), is arranged for front wheel drive by a front engine. A modified form of reversing gear employing a lay shaft is described but not illustrated. A further form of reverse gearing is described with reference to Fig. 7 (Comp.) (not shown). The transmission may be supplemented by known means enabling the primary and secondary shafts to be coupled at synchronism and such means may act automatically ; they may take the form of a friction clutch, which may be centrifugally controlled so as to uncouple automatically below the certain speed, or the form of a dog clutch with synchronizing mechanism ; controls may also be provided for putting such coupling means out of action when desired ; mechanism of this kind is described below with reference to the first Provisional Specification. The first Provisional Specification describes a torque converter comprising, Fig. 1 (Prov.), in addition to the pump blades 3 and turbine blades 6, guide blades 20 and reaction blades 9, both these sets of blades being allowed to rotate forwardly but being prevented from rotating backwardly by means of free-wheels 10, 81, the stationary parts of which are formed on a common member 82 locked to the fixed casing by an Oldham coupling. The end of the driving shaft 1 carries teeth 88 and the end of the turbine shaft 5 carries teeth 86 ; direct drive is effected when teeth 97 on a member 94 engage the teeth 88, other teeth 96 on member 94 being permanently in mesh with the teeth 86. Member 94 is urged to the left by a spring 98 but is prevented from completing its movement by a baulking member 90 mounted on the driving shaft 1 by means of a free-wheel 93 permitting it to under-run but not to over-run said shaft. If the shaft 1 be suddenly decelerated, the baulking member is rendered inoperative and member 94 is moved to the left by the spring, thus engaging direct drive. Centrifugal weights mounted on the turbine shaft cause automatic de-clutching if the speed of the driven shaft falls below a predetermined value, and alternatively permits clutching above said speed. De-clutching may be effected at will by means of a pedal 113. The transmitter is provided on its output side with mechanical gearing yielding positive forward, geared reverse, neutral and a position in which all the parts are locked together to serve as a parking brake. The free-wheels 10, 81 may be replaced by brakes actuated by free-wheel devices gear driven from the respective wheels and acting, e.g. through cams on the brake shoes. The guide blades 20 may be prevented from rotating forwardly by a brake to effect converter braking on long hills ; this brake may be actuated by the pedal 113 when pressed beyond the position necessary to release the dog clutch. The centrifugal release device may be dispensed with ; in that case the vehicle brakes are actuated by the pedal 113 when pressed beyond the position necessary to release the dog clutch. The dog clutch may be replaced by some other construction of clutch or by a fluid coupling controlled at will or by synchronizing means similar to those described above.