US2984221A

US2984221A - Rotary actuator

Info

Publication number: US2984221A
Application number: US745981A
Authority: US
Inventors: Stanley Van Voorhees
Original assignee: Douglas Aircraft Co Inc
Current assignee: Douglas Aircraft Co Inc
Priority date: 1958-07-01
Filing date: 1958-07-01
Publication date: 1961-05-16
Anticipated expiration: 1978-05-16

Description

y 1961 s. VAN VOORHEES ROTARY ACTUATOR Filed July 1, 1958 FIG. 3 @5322? INVENTOR. 5 2/m9 %/v Vida/55 B Y 254% I vW aeme/ v R la Unite tates lPatent @fitice Patented May 16, 1961 ROTARY ACTUATOR Stanley Van Voorhees, Los Angeles, Calif., assignor to Douglas Aircraft Company, Inc., Santa Monica, Calif.

Filed July 1, 1958, Ser. No. 745,981

Claims. (Cl. 121-99) This invention relates to hydraulic oscillatory or rotary actuators, in which it is well known the sealing of the rotor to the stator is, by all now-known means, far from satisfactory, for many reasons, of which excessive leakage is one.

The present invention is particularly suited for scaling to a cylindric stator rounded at each end and having a bore with radially inwardly projecting lands, the blades of a dual-bladed oscillatory rotor. Herein, in one specific embodiment of the invention, the blades are fluid-tightly sealed to the lands, and to the inner surface of the casing between the lands, by endless, wrap-around elastomeric seals, preferably O-shaped in cross-section. There may be but one endless seal or band and whether one or two are employed, they are each mounted in a groove extending along the edge of a first rotor blade, thence around the adjacent end portion of the rotor body, thence along the edge of the second blade, and thence back up around the end of the rotor body, as well as along that portion of the rotor body that contacts the lands. Four such endless packings are preferably employed in a two bladed rotor, although two will suflice, leakage being substantially prevented in either case.

In another one of the now contemplated species of the invention, the casing, or stator, is divided on its vertical center plane into two symmetrical halves, bolted or otherwise disengageably united together. Each of these halves includes one-half of an upper Working chamber and one-half of a lower such, these half-chambers being separated by a land, or abutment, protruding inwardly in the horizontal center plane of the actuator as shown in Fig. 3. When the casing halves are bolted together, the completed upper chamber and the completed lower chamber each receives one of the vanes, or blades, that protrude radially, on substantially the vertical center plane of the actuator, as shown, from the substantially cylindric central body portion of the elongate rotor, the latter terminating at each end in a cylindric journal borne in bearings at the ends of the casing.

Sealing of the vanes with respect to the casing, as well as sealing of the vaneless body of the actuator with respect to the adjacent abutments or lands, and sealing of the body with respect to the casing in the general region of the journals, are all achieved by a single type of continuous sealing instrumentality. Preferably, said means comprise a plurality of properly placed and configured integral, one-piece extents of an endless elastomeric material, such as a chloroprene polymer or the like, of circular, or the like, cross-section. Preferably, also, each such endless article can be paralleled congruently and coextensively by a more rigid piece, or pieces, of a synthetic organic plastic back-up washer of low frictional coeflicient.

In this specific embodiment of the present concepts, there are two vanes, two abutments and four endless, continuous oval-perimeter, O-rings. One of these rings is distortion stressed against a continuous seat or groove extending in the casing and in the abutment on each side of each of the two working chambers in each casing half. That is, considering each casing-half to contain two half-chambers, a ring in each groove extends around the entire perimeter of each half chamber; longitudinally along the adjacent land, and thence back to the point of origin aforesaid. The more rigid back-up means contemplated and shown herein contiguously parallels each O-ring, in each groove and along each portion of each O'ring.

The presently-preferred embodiment of these, and other, concepts is shown in the affixed drawings and described in conjunction therewith hereinafter by way of example, only.

In these drawings:

Fig. l is a longitudinal view of the novel rotor and its casing, the rotor being shown in section and the casing being shown in a side view;

Fig. 2 is an enlarged perspective view of the unit, showing the sealed rotor in full and showing its casing in section;

Fig. 3 is a transverse central section view of the unit taken at line 33 of Figure l; and

Fig. 4 is a view, similar to that of Fig. 3, of an alternative embodiment of the invention.

As shown in Figs. 1, 2, and 3, the oscillatory object to be sealed to its housing is here shown as a rotor unit for an actuator and comprises a rotor body 11 coaxially mounted in a casing or housing 17, the body 11 terminating oppositely in shaft-portions, or journals, 10.

The rotor body is generally cylindric with a pair of diametrically opposed impeller blades 12 and 13. The central cylindric portion of the body 11 is rounded at each

end

14, 15 into congruency with the adjacent concave inner face of the housing 17. The blades 12 and 1-3 are integral with the cylindric central portion and extend radially outwardly therefrom into close juxtaposition with the inner surface of the housing. At their longitudinal extremities, the blades are rounded both to fair into the body 11 and to follow the contour of surface 16.

Bearings 20 and 21 for the rotors journals are press fitted in the opposite ends of housing 17. The blades 12 and 13 are located, as is usual, peripherally between the stator elements 31, for this is an oscillatory actuator. It is particularly suited for operating an elevator of an aircraft upwardly and downwardly through respective angles of not over 30.

In order to establish and maintain a close, pressure-fluid proof fit between each of blades 12 and 13 and the housing as the rotor operates, as well as between the central portion of the rotors body and the lands '31 on the inner surface of the housing, the invention provides four

seal elements

18, 19, 50 and 51. Each element is an endless, wrap-around elastomeric band, preferably of O-Section. For laterally rollably seating these novel O-rings so that the rubber may be kneaded to preserve its desired original properties even when exposed to oils and the like, grooves 24 are provided in the casing and a pair of them extends longitudinally opposite each end face of each blade, the grooves 24 also extending around the ends of the stator body and opposite each of the two unbladed side faces 30, as shown in Fig. 3.

As shown, spacer plates 60 are provided and each O-ring is, as shown, backed up by washers 40 of a suitable organic synthetic plastic.

As a corollary to the aforestated main concepts, it is obvious that each rotor may bear but one vane or blade and necessary abutments or abutment means may be provided on the stator. The casing would then of course include but a single working chamber for this single vane. As a consequence, only two O-rings would be employed.

The fluid, under pressure, enters an inlet cavity 23 that lies between a land 31 and the adjacent normally upper, rotor blade 12 and passes to a similar inlet cavity 25 formedon the'opposite side of this blade. The auxiliary cavities 33 and34 are intercommunicated with each other by the same kind and arrangement of channelling as that which has already been described herein.

A control valve 36 is provided for use in controlling and directing the sense of rotation of the rotor and, as shown, an individual fluid passageway leads from each of the

cavities

24, 25,- 33 and 34 to this valve. The operation of the device thus becomes apparent.

In that species of the invention which is depicted in Fig. 4, the disposition of the grooves and O-rings with respect to the vanes, housing and rotor is reversed from the arrangements shown in Figs. l-3, inclusive. Also, the blades are of narower width and the abutments are of greater width, proportionately, than in the last said figures. Otherwise, the configuration and operation of the invention'are substantially the same as those aforesaid. The arrangement and configuration of the pressure fluid supply and exhaust is also substantially the same as in Fig. 3.

More specifically, the seating grooves 90 are disposed in and run along the vane-ends, the cylindric unvaned body of the rotor and around the ends of this rotor. rings substantially identical to those aforesaid are mounted in grooves 90 and are backed-up by the same kind of washers, 40. It is believed that, in conjunction with the preceding detailed description of Figs. 1-3, inclusive, the nature and operation of the species of Fig. 4 is now obvious.

Although certain specific terminology as to shapes, parameters, etc. has hereinabove been employed, it is to be understood that such usage is made solely in order to render the description of a specific embodiment more concrete. Such in no wise limits the scope of the invention defined by the appended claims.

I claim:

1. A hydraulic actuator that includes a generally cylindric casing bearing a pair of diametrically opposed radially inwardly extending abutments running along the length of said casing; a rotor coaxially mounted in the casing and having a central cylindric portion contiguous to said abutments, the cylindric portion of the rotor defining with said abutments a pair of diametrically opposed chambers for receiving a pressure fluid; a pair of diametrically opposed vanes extending radially outwardly from and running along the length of said cylindric portion, one of said vanes lying in each of said chambers and the end-face of each vane being contiguous to the inner surface of the casing; a plurality of endless groove in the interior of said casing, each groove having a portion running longitudinally of the mid-nortion of the wall of one of said chambers, a portion running longitudinally of the end face of one of said abutments and portions in the end walls of the chamber connecting said first two portions; each of said endless grooves defining a scalable pressure fluid receiving zone; an endless elastomeric sealingmember seated in each of said grooves to contact an end face of a vane and the cylindric portion of the rotor to establish a completely sealed zone; and means providing for entry and exit of fluid under pressure to each of said zones.

2. A hydraulic actuator as claimed in claim 1 in which said groove portions in the lengths of the chambers and the lengths of the abutment faces are laterally enlarged to accommodate portions of adjacent sealing members in side by side relationship.

3. A hydraulic actuators as claimed in claim 2 and, in addition thereto, substantially rigid, substantially frictionless back-up means for stabilizing said sealing members; said back-up means being seated in said groove portions substantially coextensively with said sealing member portions and lying in parallelism thereto.

4. A hydraulic actuator that includes a generally cylindric casing bearing a pair of diametrically opposed radially inwardly extending abutments running along the length of said casing; a rotor coaxially mounted in the casing and having a central cylindric portion contiguous to said abutments, the cylindric portion of the rotor defining with said abutments a pair of diametrically opposed chambers for receiving a pressure fluid; a pair of diametrically opposed vanes extending radially outwardly from and running along the length of said cylindric portion, one of said vanes lying in each of said chambers and the end-face. of each vane being contiguous to the inner surface of the casing; a plurality of endless grooves in the interior of said casing, each groove having a portion running longitudinally of the mid-portion of the wall of one of said chambers, a portion running longitudinally of the end face of one of said abutments and portions in the end walls of the chamber connecting said first two portions; each of said endless grooves defining a scalable pressure fluid receiving zone; an endless elastomeric sealing member seated in each of said grooves to contact an end face of a vane and the cylindric portion of the rotor to establish a completely sealed zone; and means providing for entry and exit of fluid under pressure to each of said zones; said last named means including means to flow-connect diametrically opposite zones.

5. A hydraulic actuator that includes a generally cylindric casing bearing a pair of diametrically opposed radially inwardly extending abutments running along the length of said casing; a rotor coaxially mounted in the casing and having a central cylindric portion contiguous to said abutments, the cylindric portion of the rotor defining with said abutments a pair of diametrically opposed chambers for receiving a pressure fluid; a pair of diametrically opposed vanes extending radially outwardly from and running along the length of said cylindric portion, one of said vanes lying in each of said chambers and the end-face of each vane being contiguous to the inner surface of the casing; a plurality of endless grooves in the interior of said casing, each groove having a portion running longitudinally of the mid-portion of the wall of one of said chambers, a portion running longitudinally of the end face of one of said abutments and portions in the end walls of the chamber connecting said first two portions; each of said endless grooves defining a scalable pressure fluid receiving zone; an endless elastomeric sealing member seated in each of said grooves to contact an end face of a vane and the. cylindric portion of the rotor to establish a completely sealed zone; and means providing for entry and exit of fluid under pressure to each of said zones;.said means including passages extending generally diametrically through said cylindric portion to flow-connect diametrically opposite zones.

References Cited in the file of this patent FOREIGN PATENTS 623,229 Great Britain May 13, 1949