US1995755A - Rotary motor - Google Patents

Description

March 26, 1935.- C;l H, SMITH 1,995,755

ROTARY MOTOR Filed July 17, 1935 Patented Mar. 26, 1935 intresen'rsu'r OFFICE ROTARY MOTOR George H'. Smith,

Worcester, Mass.

Apncatien July i7, i933, serial No. 680,732

` 1 claim. (c1. 121-93) The principal objects of thisinvention are to provide an improved hydraulic or oil moto-r of the rotarytype; to provide the rotor separated from the stator slightly so as to leave a film or body of the propelling` oil'under pressure for lubrication between all surfaces, so that no other lubrication will be necessary and there will be no danger of any of the surfacesrunning dry, and there will be a minimum of friction and a'maxirnum efficiency and only a small loss due to leakage; toprovide an outer casing or ystator having an inner cylindrical surface with no ellipticalv or inwardly projecting surfaces; to provide two fixed, directly opposite, hardened steel'plates or abutments secured to -this concave cylindrical surface, said abutments having their entrance ends tapered to close the vanes gradually without shock and their rear ends abrupt, so that when` oil is forced into the chamber between the abut-v ment and vane, as the vane leaves the abutment, the force reacts againstthe end of the abutment and forces the vane pivoted on the rctort'o swing outwardly instantly; to provide a construction in which the speed is controlled 'by the volume of oil underpressure forced into the motor, giving high static pressure and allowing steady variable speed fromzero toa maximum at high efficiency at low speeds aswell Vas high, which cannot be obtained by velocity rotation; -to provide a construction in which-the two equal oil chambers, at the point or instant of vane opening, are of full area so that the vane will open instantly when the vane operating lever touchesthe high point of its operating cam, without rubbing on the'inclined surfaces of said cam; Lto provide a` rotor so shaped and recessed that there is no projection to produce back pressure; to. provide a vane stop on the rotor outside the'swinging center of the vane to take thestrain from v.leverage of the vane and the vane bearings; i705 arrange the. vanes sothatthey must always be fully open before they begin to act; to provide a vane operating cam which is so set that it startsjmovementof the vane at a Xed point at each opening of the vane; to so shape the cani as to hold two'vanesin starting position, thus instantly providing a non-stalling feature, no matter in what position the rotor stops; to space the vanes so that two of them are always working and only one vane is opening or clos-ing at the same time, so that their motions have no eiiect on the steadiness of rotation; to provide torquelever arms for the vanesI in which their effective length `is always constant; and to set the vanes in the rotor on an angle and shape them for the following reasons; to prevent suction and trapping of oil between them and the rotor, to secure quiet and eiicientA closing without shock, to provide a short movement in opening and closing, to provide a pressure surface on the vane in the formcf a pocket of about a 90 angle so that the general exerted force of the oil acts nearly normally and opposite to a stop for the vane on. the rotor, giving pressure direct tothe outside edges of the rotor as far from its center of rotation as possible; to provide the vane with a slightly inclined outer surface to give a greater width of oil seal between it and the stator; to provide a stop on the rotor to hold the vane. so that its-` outside inclined edge does not actually rub on the inner surface of the casing or stator, Aallowing clearance as stated above, to avoid side sliding on the side plates during action, but still allow clearance for the purpose described above, and to'locate the vanes atsuch an angle as to prevent seizure between thestator and rotor in case of overheating and expansion. y A

VOther objects and advantages of the invention will appear hereinafter.

Reference is to be had-'to the accompanying drawing, in which v Fig. 1 is a diametrical sectional view of a rotary motor showing a preferred form of this invention; Fig. 2 is a sectional view on the line 2-2 of Fig..1;

,Fig. 3 is an end view showing the casing and shaft in section on the line 3--3 of Fig. 1; and

Fig. .4 is a sectional view on the line 4 4 of Fig. 2.

The motor comprises a stator or stationary casing 12 and a rotor consisting of two flat discs l5spaced apart by a central member 16 or rotor proper. The rotor is fixed to a central shaft from which power is transmitted through any suitable means, as a pulley 4. The three parts of the rotor are rmly secured together by any desired means, as bolts 7 and nuts. These three parts can be made in one part or two if desired.

The central part 16 of the rotor is provided With marginal sector-shaped recesses `1'7 which constitute more than half of a cylindrical surface in each case, van odd number, ive, being shown. Each recess is provided with a stop 18 and an opposite stop 19. In the neck of each recess is located a cylindrical hub 22 on a vane 21. In this way the vane is positively pivoted and cannot move toward or from the center of the rotor. The hub of each vane is provided with a stub shaft on each end passing through and pivoted in perforations in the discs 15. The circular discs 15 extend to the inner concave surface 3 of the stator or casing with just enough clearance 25 to provide lubrication and prevent rubbing. The inner member 16 is spaced from the surface 3 to provide a space 5 all around. This space 5 is divided into two equal chambers by two opposite abutments 24 between the two discs 15 and fixed to the stator. The cylindrical surfaces of the discs l5 fit, with a running fit, the inner sur* face of the stator, leaving a clearance 25. The entrance end 2 of each abutment is tapered and the rear end 6 is abrupt. At the end 6 they are out away at 2 to provide a port. Between these ends the abutments are concave at 23 to t the rotor 16.

The vanes, one on each stub shaft 20, are capable of reaching to the surface 3. They are slanted at their extreme ends and so proportioned with reference to the stops 18 as to run along the surface 3 with a running contact'providing a slight clearance 30 for lubrication and to prevent rubbing. This relieves the motor of friction around the circumference. This leaves a space for the oil introduced through two opposite inlets 13 to run in and out through two opposite outlets 14. This oil under pressure is admitted on opposite sides, avoiding the thrust of the rotor against the casing and the friction thereby is reduced.

Outside one disc 15 on the stub shafts 20 are located a set of cam arms 26 extending inwardly. The casing 12 is provided with a stationary double cam 11 inside the casing and outside the disc for operating the vanes as the rotor turns. This cam is so shaped that there are always two portions of the cam holding two vanes in operative position. Thus, when the motor is stopped, there are always two vane arms in proper position to rest on the circular face of the cam so that at any instant, power can be applied to these two vanes to force them back immediately against their stops 19 which hold the vanes in their open operative position. Rotation can be started promptly. This constitutes a non-stalling provision and it does not make any difference where the motor stops. The vane does not propel the motor until it comes against the stop, so that the effective length of the cam-arm 26 is always constant.

A groove 9 is provided in the flat surface of the stop 18 against which the vane shuts. 'I'his surface is cut down by this groove 9 to admit oil and prevent these two surfaces holding together.

The discs 15 rotate with a minimum friction. There is a space 1/36'l or more between all flat sides and surfaces of the rotor and the adjacent walls of the stator which is lled with oil under pressure. The fitting of the discs 15 at the circumference is a sliding fit, one thousandth of an inch space or more being left. Therefore, the device is not only self lubricating but, the oil being under pressure, friction is maintained at a minimum. There is leakage, but not very much. I have secured volumetric efliciency of 90% with a small model.

It will be seen that as the oil is admitted to this motor the cam 11 and arm 26 will hold a vane 21 at the bottom, in Fig. 2, in such position that the space between the member 16 and the surface 3 of the casing will be closed. As the oil enters at 13, in the direction of the arrow, and

.the vane at that point is held positively outward by the cam 1l, the rotor will start instantly. The pressure of the oil forces the vane against the stop 19 which is so positioned as to take the end of the arm 26 off the cam 11. Until the vane touches the abutment 24 it stays out in operative position. It is free from the cam all this time. The vane is then positively closed down by the abutment. When it runs off the abutment it opens suddenly and receives the full force of the oil entering at the upper inlet 13.

This motor is of simple construction and a great deal of gearing usually thought necessary is eliminated.

The motor is non-stalling and can be used on almost any make of machine, whether used for grinding, cutting, or other purposes. The installation is simple and the upkeep inexpensive as it is substantialy self-lubricating. The rotor can be run at widely varying Aspeeds accordingl to the amount of oil introduced.

The oil spaces between the rotor and casing take care of both side and end thrust. The discs at the sides of the rotor, carrying bearings for the propeller shafts, rotate with the rotor, of course,

and prevent sliding action and friction on the side walls. On account of the presence of oil under pressure all around the machine is kept in hydraulic balance.

Although I have illustrated a speciflc motor, I :L

am aware of the fact that modifiactions can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore, I do not wish to be limited in this respect otherwise than as set forth in the claims, but what I claim is:-

A rotary hydraulic motor comprising a central shaft, a casing around it having an inner concave cylindrical surface, an inlet to the casing, an outlet from the casing, a rotor fixed to the shaft, comprising two discs spaced apart and a central member between them, a series of vanes pivotally mounted on the discs, two pivot studs fixed with respect to each vane and supported by the discs, one end of each pivot stub on one side extending through its disc, a cam arm on the extending end of each extending stub outside the disc and inside the casing, a stationary cam centered on, but not fixed to, the central shaft for engaging said arms as the rotor rotates and opening the vanes so that the entering liquid will rotate the rotor, and means for holding the vanes in position to prevent their exerting pressure on the inside of the casing, the vanes being of such length as to engage the inside surface of the casing to prevent the arms rubbing on the cam after the vanes are

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