US3053232A

US3053232A - Damper reservoir gas actuator

Info

Publication number: US3053232A
Application number: US54648A
Authority: US
Inventors: Richard E Self
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1960-09-08
Filing date: 1960-09-08
Publication date: 1962-09-11
Anticipated expiration: 1979-09-11

Description

Sept. 11, 1962 R. E. SELF 3,053,232

DAMPER RESERVOIR GAS ACTUATOR Filed Sept. 8, 1960 IN VEN TOR.

w ivy United States This invention relates to rockets, missiles and related air and space-borne vehicles and is more particularly directed to improved methods and means for damping resonance in rotor vane compartments of oscillatory actuator units and the like.

Heretofore, it has been customary in the art to employ the same pressurizing medium, hydraulic or pneumatic, received from a common source or reservoir as the operating fluid for all the rotor vane compartments of an oscillatory actuator unit of a servomechanism or the like, regardless of the number of vane compartments involved.

For proper operation of the actuator unit, wherein the rotor carried vanes are movably responsive to the creation of differential pressure conditions in the rotor vane compartments on opposed sides of the vanes, each of the vane compartments was constantly under pressure; similarly, the external sources or reservoirs of the hydraulic or pneumatic pressurizing medium for proper operation of the actuator unit. To prevent excess oscillatory movement of the vanes and rotor and the condition commonly referred to as hunting in response to a change in pressure conditions in vane compartments on opposed sides of the vanes, pressure responsive damping means were employed in conjunction with the reservoirs for regulating the flow of pressurizing medium to the vane compartments involved.

The conventional spring-loaded or fluid-damping means, the pressurized reservoirs and the pressurized vane compartments, however, collectively, contributed to an actuator unit having vane compartment leakage tendencies. Leakage of pressurizing medium from the actuator unit and leakage across vane compartments attributable to the requirement for pressurization of the reservoirs, damping means and vane compartments tended also to create an operating situation which the reservoirs and damping means were specifically designed and intended to avoid. For leakage from the vane compartments would render ineffective the predetermined calibration of the damping means, the pressure level applied to the reservoirs and, in addition, the expected operation of the pressure changes in the vane compartments resulting in excess oscillatory movement of the vanes and rotor-the operating conditions intended to be avoided.

I substantially overcome the problems and difficulties of the prior art and, more specifically, eliminate the requirement for pressurized external reservoirs and pressurized external damping means, utilize available space heretofore considered Wasted in the actuator rotor shaft, and additionally, my invention increases the stiffness and reduces resonance in the operation of the unit by employing a damping medium less viscous than the operating medium Without increasing the leakage tendency of the vane compartments and permits storage of the damping medium under non-pressure conditions.

It is, therefore, an object of the present invention to provide improved methods and means for damping resonance in rotor vane compartments of oscillatory actuator units and the like.

It is another object of the present invention to provide improved damping means for oscillatory actuator units and the like.

It is still another object of the present invention to provide actuator dampening means which are not under constantly changing pressure forces.

ate

A further object of the present invention is to eliminate the requirement for external pressurized damping means and reservoirs for oscillatory actuator units and the like.

A still further object of the present invention is to provide improved methods and means for damping operation of an oscillatory actuator unit utilizing heretofore Wasted or unused space of the unit.

These and other objects, features and advantages of the present invention will become more apparent from a careful consideration of the following detailed description, when considered in conjunction with the accompanying drawing, wherein like reference numerals and characters refer to like and corresponding parts throughout the several views.

On the drawing:

FIGURE 1 is a view in longitudinal cross-section of an actuator unit embodying the principles of my invention.

FIGURE 2 is a view in cross-section taken along lines 11-11 of FIGURE 1.

As shown on the drawing:

While the present invention has a variety of applications and particularly with actuator units having more than a pair of rotor vanes, the description now to follow will relate to the actuator unit shown in the drawings wherein the oscillatory rotor carries but a pair of vanes.

Briefly stated and as appears in FIGURE 1, an oscillatory actuator constructed in accordance with my invention includes a housing generally indicated by the numeral 3, defining a central chamber and a pair of (wedgeshaped radiating branch chambers.

Located in the central chamber of the housing is a rotor 4 carrying or having integrally formed therewith a pair of vanes 5 and 6, each of which extends into one of the branch chambers separating the chambers into a pair of vane compartments.

Thus, vane 5 separates the housing branch chamber into a pair of pressurizing

medium vane compartments

7 and 8 respectively, each of which communicates with a housing formed inlet 7a and 7b respectively for introduction of a pressurizing medium thereto as appears in FIG- URE 2. The periphery of the leading edge 5a of vane 5 is grooved to receive a seal 9, preferably of elastomeric material in wiping contact with the arcuate surface 3a of the housing for preventing leakage of the pressurizing medium across the leading edge of the vane into the

opposed vane compartments

7 and 8.

The oscillatory rotor 4 is provided at each end with a flange 4a and 4b respectively contoured to the

stepped web portions

10 and 11 of the housing 3 as appears in FIGURE 1. The rotor 4 is grooved at diametrically opposed sides to receive a pair of

elastorneric seals

12 and 13 which are contoured to the rotor and end flanges terminating at each end in abutting engagement with a pair of annular elastomeric seals 14 and 15 sealed in grooves formed in the end flanges 4a and 4b.

Seals

12 and 13 engage the housing web surfaces 10a and 1111 respectively in Wiping contact permitting oscillatory movement of the rotor while preventing pressurizing medium leakage across the rotor Whereas seals 14 and 15 engage the housing in wiping contact to permit oscillation of the rotor preventing leakage across the flanges from the vane compartments.

As appears at the right in FIGURE 1 a balance platen 16 is positioned in the housing in engagement with a shoulder 18 provided by a stepped portion of the housing and is bored to permit one end of the rotor shaft 19 to extend therethrough. The platen is grooved to receive seal means 20 for leakage sealing of the housing and platen and With seal means 21 for leakage sealing of the shaft. Similarly, the platen is provided with a seal 22 in engagement with the end flange 4b to permit oscilla- 3 tion of the rotor. A retaining ring 23 threadedly engages the housing 4 to secure the balance platen 16. A seal 24 may also be provided to further ensure a leakproof assembly.

In oscillatory actuator units, a similar retaining ring, balance platen and seal means would be provided at the other end of the vane compartments and a pair of shaft formed passages would also be provided communicating the

vane compartments

7 and 8 with opposite compartments 8a and 7c respectively defined by vane 6. Thus, by introduction of a pressurizing medium into the compartments, the rotor would be held in a stationary position relative to the housing, when pressure equilibrium existed in the compartments.

However, if a pressure differential existed in the vane compartments on opposed sides of the vanes, the vanes and rotor would move in the direction of low pressure and thus move the rotor shaft correspondingly. Coupling of the rotor shaft to flight control surfaces of the vehicle with which the servomechanism was employed, such as elevators, or gimballed nozzles of a rocket and related vehicles, would move the flight control surface in the desired direction imposing a corrective movement to the vehicle.

Changes in pressure conditions in the vane compartments to move the vanes in either direction may be regulated by valve means associated with the conduits (not shown) communicating conduits 7a and 7b with the pressurizing medium source (not shown).

The discussion now to follow relates to the improved damping means of the present invention.

As appears in FIGURE 1, a balance platen 27 is provided at the left end of the actuator unit and is recessed to define a chamber 28 communicating with an actuator housing formed passage 29 through a passage 30 shown by the dotted lines. The balance platen 27 is provided with leakage seal means 31 to prevent leakage across the housing from the passage 29 and chamber 28, with seal means 32 to prevent leakage along the rotor shaft and seal means 33 to prevent leakage across the end flange 4a while permitting oscillation of the rotor. A retaining ring 35, similar in construction and operation to retaining ring 23, is also provided and similarly an annular seal 36 may be employed.

The rotor shaft 19 is bored to receive a piston assembly 37 therein, the piston head 37a separating the shaft bore into a pair of

opposed compartments

38 and 39. The bore of the rotor shaft is dimensioned to permit sliding contact of the piston head with the complementary wall of the shaft. The end wall of chamber 38 is defined by a packing gland 40, provided with seal means 40a and 40b, which is retained by a snap ring 41. The packing gland 40 is dimensioned to prevent the piston head 37a from leaving its track when the piston is in its most rearward position to the left in FIGURE 1.

A passage 42 formed in the shaft communicates the chamber 38 with the chamber 28.

To permit movement of the vanes, a conduit 50 interconnects the damping compartments 7c and 8a for flow of oil between the compartments. A conventional control valve or orifice 50a may be provided to calibrate and to meter the flow from between the chambers as the vanes move relative to the housing. The chamber 28 and thus chamber 38 may be pressurized by introduction of a pressurizing medium through passage 29 to thereby urge the piston head 37a to the right thereby creating a pressure in chamber 39. If desired the pressurizing medium may be tapped from the source employed to pressurize the

vane compartments

7 and 8 to ensure equal pressure application in chamber 39.

Chamber 39 communicates with each of vane compartments 7c and 8a through actuator shaft formed passages 44a and 44b and transverse passages 44c and 44d respectively, each of which is provided with a one-way check valve, 45 and 46, which permits flow into the vane compartments from chamber 39.

To permit movement of the vanes, a conduit 50 interconnects the damping compartments 7c and St: for flow of oil between the compartments. A conventional control valve or orifice 50a may be provided to calibrate and to meter the flow from between the chambers as the vanes move relative to the housing.

-A stepped bore 19a is provided in the piston 37 and a one-way check valve 49 is provided which permits flow into chamber 39. Means are thereby provided to supply a damping fluid to the vane compartments 7c and 8a.

Thus, a damping medium, such as oil, may be supplied to the vane compartments 7c and 8a to provide an operating stiffness to the actuator unit unobtainable with conventional gas operated servomechanism actuator units and to provide a reserve of oil which is responsive to the operating conditions of the actuator unit to maintain the damping conditions in the damping vane compartments relatively constant.

In operation, a damping medium, such as oil, is introduced into the damping compartments 7c and 8a through passage 19a, chamber 39 and passages 44a and 44b and transverse passages 44c and 44d. The required stiffness or pressure in the dampening compartments is established with orifice 50a.

A pneumatic pressurizing medium is introduced into

vane compartments

7 and 8 through the housing formed passages 7a and 7b and a condition of pressure equilibrium is established in the compartments 7a and 7b, whereby the rotor is maintained stationary relative to the housing 3.

A portion of the pneumatic pressurizing medium from the supply source may be by-passed into the chamber 38 behind the piston head 37a through passage 36, chamber 28, and housing formed passage 29 to exert a force to the right in FIGURE 1 which in turn develops a hydraulic force or pressure in chamber 39. This pressure then is applied to the oil in both of the vane compartments 7c and 8a through the check valves in the shaft passages 44a and 44b. The pressure compartments 7a and 8c and check valves 45 and 46 cooperate to prevent passage of oil into the damping compartments as long as the pressure in the compartments is at the desired level. Should oil possibly leak from either or both of the damping vane compartments when the hydraulic control valve 50a is initially regulated to develop the desired level of operating stiffness for the actuator unit or during operation, the pressure in reservoir 39 would force oil from the reservoir chamber 39 into either one or both of the damping vane compartments, as required. Similarly, if oil should leak from the damping compartments during operation, the force exerted by the piston would force additional oil into the damping compartments to compensate for the loss as a function of operating conditions of the actuator unit.

When the unit has been properly calibrated, the unit may be stored, leaving the oil in the compartments and reservoir chamber under non-pressure conditions. Of course it will be appreciated that the piston will be suitably secured to prevent movement thereof for storage purposes.

'Thus by my invention, I provide actuator damping means which eliminate heretofore required external components, utilize heretofore waste space in the actuator unit and permit storage of the damping oil under other than pressure conditions when the unit is not in service.

Although various modifications might be suggested by those versed in the art, it should be understood that I Wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. An oscillatory servomechanism actuator unit comprising: a housing; a shaft and vane carrying rotor in said housing cooperating therewith to define at least one pressurizable damping compartment and at least one pressurizable operating fluid compartment; a bore in said shaft receiving piston means for separating the bore into a pair of chambers; means for introducing a pressurizing medium into one of said chambers; means for introducing a damping medium into the other of said chambers; means communicating said latter chamber with said damping compartment whereby the pressurizing medium acting on said piston means supplies a damping medium into said damping compartment to compensate for leakage losses therefrom, and means for introducing a pressurizing operating medium into said operating compartment.

2. An oscillatory servomechanism actuator unit comprising: a housing; a shaft and vane carrying rotor in said housing cooperating with said housing to define at least one pressurizable damping compartment and at least one pressurizable operating fluid compartment; a bore in said shaft; a piston in said bore separating the bore into first and second chambers; a shaft formed passage communicating with said first chamber for introducing a pressurizing medium thereto; a shaft formed passage for introducing a damping medium into said second chamber; a passage communicating said second chamber with said damping compartment whereby a pressurizing medium acting on said piston supp-lies a damping medium from said second chamber into said damping compartment to compensate for leakage losses therein; and a passage for introducing a pressurized operating fluid medium into said operating compartment.

3. An oscillatory servomechanism actuator unit comprising: a shafted rotor; a plurality of vanes on said rotor cooperating with said housing to define at least one pressurizable damping compartment and at least one pressurizable operating fluid compartment; a bore in said shaft; a piston in said bore separating the bore into first and second chambers; a shaft formed passage for introducing a pressurizing medium into said first chamber; a housing formed passage for introducing a damping medium into said second chamber; a passage communicating said second chamber with said damping compartment whereby the pressurizing medium acting on said piston supplies the damping medium into said damping compartment to compensate for leakage losses therein, and means for introducing a pressurizing operating medium into said pcrating compartment.

4. An oscillatory servomechanism actuator unit comprising: a housing; a shafted rotor in said housing; a pair of vanes carried by said rotor, said rotor and vanes cooperating with said housing to define a pair of pressurizable damping compartments and a pair of pressurizable operating fluid compartments; a bore in said shaft; a piston in said bore separating the bore into first and second chambers; a shaft formed passage for introducing a pressurizing medium into said first chamber; shaft formed passages communicating said second chamber with said damping compartments whereby the pressurizing medium acting on said piston supplies a damping medium into one of said damping compartments to compensate for leakage losses therefrom; and housing formed passages for introducing a pressurized operating fluid medium into said operating compartments.

5. An oscillatory servomechanism actuator unit comprising: a housing; a shafted rotor in said housing; vanes carried by said rotor, said rotor and said vanes cooperating with said housing to define at least a pair of pressurizable damping compartments and at least a pair of pressurizable operating fluid medium compartments; a bore in one end of said shaft; a piston in said bore separating the bore into first and second chambers, a shaft formed passage for introducing a pressurizing medium into said first chamber; a shaft formed passage for introducing a damping medium into the second chamber; a pair of passages communicating said second chamber with said damping compartments, whereby a pressurizing medium acting on said piston supplies a damping medium into one of said damping compartments to compensate for leakage losses therefrom; and means for introducing a pressurized operating medium into said operating compartments.

6. An oscillatory servomechanism actuator unit comprising: a housing; a shaft and vane carrying rotor in said housing cooperating therewith to define at least one pressurizable damping compartment and at least one pressurizable operating fluid compartment; a bore in said shaft receiving piston means for separating the bore into a pair of chambers; means for introducing a pressurizing medium into one of said chambers; a piston formed passage for introducing a damping medium into the other of said chambers; means communicating said latter chamber with said damping compartment whereby the pressurizing medium acting on said piston means supplies a damping medium into said damping compartment to compensate for leakage losses therefrom; and means for introducing a pressurized operating medium into said operating compartment.

7. An oscillatory servomechanism actuator unit comprising: a housing, a shaft and vane rotor in said housing cooperating therewith to define at least one pressurizable damping compartment and at least one pressurizable operating fluid compartment; a bore in said shaft receiving piston means for separating the bore into a pair of chambers; means introducing a pressurizing medium into one of said chambers; conduit means for introducing a damping medium through said piston means into the other of said chambers; a check valve for preventing flow of damping medium from said chamber; means communicating said damping medium chamber with said damping compa.rt ment whereby a pressurizing medium acting on said piston means supplies a damping medium into said damping compartment to compensate for leakage losses therefrom; a check valve for preventing flow of damping medium from said damping compartment to said damping medium chamber; and means for introducing a pressurized operating medium into said operating compartment.

8. An oscillatory servomechanism actuator unit comprising: a housing; a shafted rotor in said housing; vanes carried by the rotor, said rotor and vanes cooperating with said housing to define therebetween a pair of pressurizable damping compartments and a pair of pressurizable operating fluid compartments; seal means for preventing leakage from said compartments; end plates for closing said housing and for aligning said rotor shaft; a bore in one end of said shaft; a piston separating said bore into first and second chambers; a shaft formed passage communicating said first chamber with a pressurizing medium source through a housing formed passage; a first shaft formed passage communicating one of said damping compartments with said second chamber; a second shaft formed passage communicating the other of said damping compartments with said second chamber; valve means preventing flow through said first and second passages from said damping compartments to said second chamber; a piston formed passage for introducing a damping medium into said second chamber whereby pressure forces acting in said first chamber to move said piston supplies a portion of the damping medium to either of said damping compartments to compensate for leakage losses therefrom from said second chamber; valve means in said piston formed passage for preventing flow of damping medium from said second chamber through said piston formed passage; means for limiting movement of said piston in said bore; means for introducing a pressurized operating fluid into said operating fluid compartments, and means for, controlling pressure conditions in said operating fluid compartments to move the rotor relative to the housing.

9. In an oscillatory servomechanism actuator unit including a housing having a shaft and vane carrying rotor therein cooperating with said housing to define at least one pressurizable damping compartment and at least one pressurizable operating fluid compartment, the improvement comprising: a bore in the rotor shaft; a piston in the bore for separating the bore into a pair of chambers; means'for introducing a pressurizing medium into one of said chambers; means for introducing a damping medium into the other of said chambers; and means for introducing damping medium from said clamping chamber into said damping compartment, whereby movement of said piston in response to said presurizing medium supplies damping medium from said damping chamber to said damping compartment to compensate for leakage losses therefrom.

10. A rotor for oscillatory servomechanism actuator units and the like having at least one damping compartment comprising: a body portion; a bore in the body portion; a piston in the bore for separating the bore into a pair of chambers; means for introducing a pressurizing medium into one of said chambers; means for introducing a damping medium into the other of said chambers, and means for introducing a damping medium from said damping chamber into said damping compartment, whereby movement of said piston caused by a pressurizing medium supplies damping medium from said damping chamber into said damping compartment to compensate for leakage losses therefrom.

11. A rotor for oscillatory servomechanism actuator units and the like having at least one damping compartment, comprising: a body portion; a bore in the body portion; a piston in the bore for separating the bore into a pressurizing medium chamber and a damping medium chamber; means communicating said damping compartment with said damping chamber; means communicating said damping chamber with a damping medium source; means for introducing a pressurizing medium into said pressurizing chamber whereby movement of said piston caused by pressure forces acting in said pressurizing medium chamber supplies damping medium from said damping chamber to said damping compartment to compensate for leakage losses therefrom.

12. A rotor for oscillatory servomechanisrn actuator units and the like having at least one damping compartment, comprising: a bore in one end of the shaft of the rotor; a piston in the bore separating the bore into first and second chambers; a shaft formed passage for introducing a pressurizing medium into said first chamber; a piston formed passage for introducing a damping medium into said second chamber, and a shaft formed bore for introducing a damping medium from said second chamber into said damping compartment, whereby movement of said piston caused by a pressurizing medium supplies damping medium from said second chamber into said damping compartment.

13. A rotor for oscillatory servomechanism actuator units and the like having at least one pressurizable damping compartment, comprising: a shafted body portion; a bore in one end of said shaft; a piston in said bore separating the bore into first and second chambers; a shaft formed passage for introducing a pressurizing medium into said first chamber; a piston formed passage for introducing a damping medium into said second chamber; a body formed passage communicating said damping compartment with said damping chamber; means for preventing damping medium flow from said damping compartment to said damping chamber; and means for preventing flow from said damping chamber through said piston formed passage, whereby movement of the piston caused by pressure forces acting in said first chamber supplies damping medium from said second chamber to said damping compartment to compensate for leakage losses therefrom.

14. In the method of compensating for leakage losses from a damping compartment of oscillatory rotor actuator units and the like, the steps comprising: maintaining a pressurized damping medium in a reservoir formed in the rotor shaft, and flowing portions of said damping medium from the reservoir into the damping compartment in response to pressure conditions in said damping compartment.

15. In the method of compensating for leakage losses 8 from a damping compartment of oscillatory rotor actuator units and the like, the steps comprising: maintaining a reservoir of damping medium in a rotor shaft-formed chamber, and supplying a portion of the damping medium to the damping compartment from the chamber in response to pressure changes in said damping compartment caused by leakage therefrom.

16. In the method of compensating for leakage losses from a damping compartment of an oscillatory rotor actuator unit and the like, the steps comprising: maintaining a reservoir of damping medium in a rotor formed damping chamber, applying pressure to the damping medium in the chamber, and maintaining the pressure on the damping medium in the chamber for supplying the damping medium to the damping compartment to compensate for leakage loss therefrom.

17. A dashpot controller adapted for controlling operation of oscillatory actuators and the like comprising: a housing defining a chamber, a piston in the chamber separating the chamber into first and second compartments, an inlet and outlet to the second compartment, a damping chamber communicating with the outlet of the second compartment, means for permitting How of a damping medium only to said damping chamber from said second compartment, and an inlet to said first compartment for introduction of a pressurizing medium for urging said piston in the direction of said second compartment to thereby maintain a predetermined pressure in said damping chamber.

18. A dashpot controller adapted for controlling operation of oscillatory actuators and the like comprising: a housing defining a chamber, a piston in the chamber separating the chamber into first and second compartments, an inlet through the piston for introduction of a damping medium to said second compartment, an outlet to the second compartment, a damping chamber communicating with the outlet of the second compartment, means for permitting flow of a damping medium only to said damping chamber from said second compartment, and an inlet to the first compartment for introduction of a pressurizing medium for urging said piston in the direction of said second compartment to thereby maintain a predetermined pressure in said damping compartment.

19. A dashpot controller comprising: a housing defining a chamber, a piston in the chamber separating the chamber into first and second compartments, an axial passage in the piston for introduction of a damping medium to said second compartment, means for preventing flow from said second compartment through said axial passage, and outlet to the second compartment, a damping chamber communicating with the outlet of the second compartment, means for permitting fiow of a damping medium only to said damping chamber from said second compartment, and an inlet to the first compartment for introduction of a pressurizing medium for urging said piston in the direction of said second compartment to thereby maintain a predetermined pressure in said damping compartment.

20. A dashpot controller adapted for controlling operation of oscillatory actuators and the like comprising: a housing defining a chamber, a piston in the chamber separating the chamber into first and second compartments, an axial passage in the piston for introduction of a damping medium to said second compartment, a one-way check valve in said passage for preventing flow from said second compartment, an outlet to the second compartment, a damping chamber communicating with the outlet of the second compartment, means for permitting flow of a damping medium only to said damping chamber from said second compartment, and an inlet to the first compartment for introduction of a pressurizing medium for urging said piston in the direction of said second compartment to thereby maintain a predetermined pressure in said damping compartment.

21. A dashpot controller adapted for controlling operation of oscillatory actuators and the like comprising: a housing defining a chamber, a piston in the chamber separating the chamber into first and second compartments, an inlet passage in the piston for introduction of a damping medium to said second compartment, a one-way check valve in said passage for preventing flow from said second compartment through said passage, an outlet to said second compartment, a damping chamber, a second passage communicating the damping chamber with the outlet of the second compartment, a one-way check valve in said second passage for preventing flow from said damping chamber to said second compartment, and an inlet to the first compartment for introduction of a pressurizing medium for urging said piston in the direction of said second compartment to thereby maintain a predetermined pressure in said damping compartment.

22. A das-hpot controller adapted for controlling operation of oscillatory actuators and the like comprising: a cylinder, a first head at one end of the cylinder and having an axial bore therethrough, a passaged head at the other end of the cylinder, at reciprocable piston in the cylinder separating the cylinder into first and second compartments, said piston extending through the bore of said first head, an inlet to said second compartment for introduction of a damping medium thereto, means for preventing flow from said second compartment through said inlet, means for preventing flow through the passage in said second head into said second compartment, and an inlet for introduction of a pressurizing medium to said first compartment for urging said piston in the direction of said second compartment to thereby maintain a predetermined pressure in said second compartment.

Diebel Oct. 14, 1952 Rasmusson et a1 June 10, 1958