US3245271A - Hydraulic actuator - Google Patents

Description

.. 4z Y 44 es 5' E April 12, 1966 B. D. ROBERTS 3,245,271

HYDRAULIC ACTUATOR Original Filed Jan. 8, 1962 2 Sheets-Sheet 1 26 15 FIG-5 55 e [zo I 85 43 45 z8 "5 wir 48 'y/)TLw-' vul I. l g;

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6535 BRUCE D. ROBERTS BY 6l 70 /l `\l se Mfr@ ELT 64 75 68 62 40 ATTORNEYS April 12, 1966 B. D. RoBERTs 3,245,271

HYDRAULIC ACTUATOR Original Filed-Jan. 8, 1962 2 Sheets-Shee't 2 8O INVENTOR. v

BRUCE D. ROBERTS ATTOR NEYS United States Patent O 3,245.271 HYDRAULIC ACTUATOR Bruce I). Roberts, Central States Tooling Service Inc., 35 S. St. Clair St., Dayton, Ohio Griginal application Jan. 8, 1962, Ser. No. 164,896. Divided and this application Aug. 19, 1964, Ser. No.

s claims. (ci. 74-1o9) It is a primary objector of this invention to provide a remotely controlled hydraulic actuator characterized by its ease of connection and removal to a shaft.

A further object of this invention is to provide a hydraulic actuator which is mounted and supported directly on the shaft which is to be controlled.

A further object of this invention is to provide a remotely controlled hydraulic actuator having an output gear capsule which contains an internal arrangement for locking the actuator to a splined shaft and for preventing backlash at such connection.

A still further object of this invention is to provide a hydraulic actuator including a two-way piston motor which includes an automatic internal bleed characterized by the absence of external bleed valves and passageways.

A still further object of this invention is to provide a hydraulic actuator as outlined in the preceding object wherein the bleed valve arrangement is carried wholly within the piston member.

Another object of this invention is to provide a remotely controlled hydraulic actuator having an output gear capsule which is particularly adapted for the di-rect mounting on the splined end of a governor input shaft.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings- FIG. 1 is a diagram of a typical installation of the actuator of this invention on a jet engine in a test cell showing the actuator in elevation;

FIG. 2 is an elevational view of the back of the actuator;

FIG. 3 is a transverse section through the actuator;

FIG. 4 is a fragmentary sectional detail of FIG. 3;

FIG. 5 is a vertical section taken generally along the line 5-5 of FIG. 3;

FIG. 6 is a fragmentary section taken generally along the line 6 6 of FIG. 3;

FIG. 7 is an end view looking into the interior of the gear capsule of FIGS. 3 and 5 with the gear capsule cover removed and with the buttertiy and operato-r removed, showing the open position of the locking cams;

FIG. 8 is a view similar to FIG. 7 showing the antibacklash buttery in position with the fingers of the operator being shown in section;

FIG. 9 is an other view similar to FIG. 7, with the butterfly removed, showing the position of the fingers and locking cams when the gear capsule is locked on the shaft;

FIG. 10 is a perspective view of the butterfly;

FIG. 11 is a transverse section through the butterfly showing the manner in which it is mounted for limited angular anti-backlash movement on the pins; and

Patented Apr. 12, 1956 "ice FIG. 12 is a perspective view of the operator.

Referring to the drawings, which illustrate a preferred embodiment of this invention, a fragment of a jet engine is shown at 10 in FIG. 1 as having a throttle control governor 12 mounted thereon. A remotely controlled throttle actuator constructed according to this invention is shown at 15 as being mounted on the shaft of the governor 12. The actuator 15 is remotely controlled by a sensing unit 16 through which the governor input shaft may be accurately positioned in accordance with the position of the handle 17.

The transmitting unit 16 may consist of any suitable type of hydraulic transmitter, such as the part number 13864 of Adel Precision Products Corporation, Burbank, California, and forms no part of the present invention. The sending unit 16 and the actuator 15 form a closed loop pressurized hydraulic circuit with the hydraulic lines 18 and 19 completing the circuit therebetween.

The actuator 15 also preferably includes provision for remote recording or position indicating, such as an electrical position sender or selsyn unit 20 on the actuator 15 which is connected to a remote position indicating unit 21 through electrical leads 23.

Referring now in detail to the construction of the actuator 15, and referring to FIGS. 1-3, the major portion of the actuator consists of a block or body 25 which may be formed of aluminum and which provides support for the other members of the actuator. The body 25 is formed with opposite machined planar faces and a generally cylindrical cavity 26 within which is received an output gear capsule indicated generally at Z8 in FIG. 3.

The capsule 28 is supported for rotation within the body 25 between a pair of opposite cast covers or bearing housings. The front housing 30 is seen in FIG. l and also provides support for the sending unit 26. The rear housing 31 is annular in shape and is shown in FIG. 2 as being mounted on the back or rear surface of the body 25. The front and rear plates are shown in section in FIG. 5 where it may be seen that the front plate 30 is formed with an annular shoulder 35 within which a race 36 of ball bearings is received. Similarly, the back plate 31 is shouldered at 38 and also receives another race of bearings 39. The gear capsule 2S is mounted between the covers for rotation in the bearings 36 and 39.

The body 25 also is formed with a longitudinal bore which intersects the cavity 26. A cylinder liner 40 is received within the longitudinal bore and extends outwardly from each end thereof, and forms a hydraulic cylinder. The opposite ends of the cylinder liner 40 are closed by left and right cylinder head blocks 42 and 43 which are recessed to receive the liner 40. 'I'he cylinder head blocks are respectively secured to mating outer surfaces of the body 25 by machine screws 44 and 45. The right-hand block 43 also includes a pair of arms 48 which form a pivotal connection to a radius rod Sil by means of which the actuator may be secured against rotation relative to the governor 12.

The cylinder blocks 42 and 43 form closures for the extended ends of the cylinder liner 40 and form a seal with the body 25 and with the liner 40. Each of the blocks 42 and 43 define hydraulic fluid inlet passageways 51 and 51 communicating with the ends of the liner through the respective blocks and terminating at inlet connections 52 and 53, shown in FIG. 1.

A two-way hydraulic piston 55 is received for axial movement within the liner 4t). The piston 55 is formed in two parts including a main piston portion 56 which has a rack 58 formed thereon in engagement with the teeth of the gear capsule 28. The piston 55 includes a secondary or a movable piston portion 6i) formed with a head 61 and an extending stem 62 slidably received within a suitable axial opening or bore 63 formed in the main portion 56. Each end of the piston is formed with a recess to accommodate a V-cup ring 64 providing a seal with the liner 4i) and isolating the ends of the piston, forming separate hydraulic chambers 65 and 66 at the opposite ends thereof.

The two portions and 56 of the piston 55 form a valve which, is normally closed during operation, as shown in FIG. 3, but which is open when the hydraulic system is depressurized to provide communication through the piston 55 between the chambers 65 and 66 for the purpose of bleeding the actuator 15. A passageway 67 is formed through the right-hand portion of the piston 55 and communicates into the interior of the bore 63.

The bore 63 is formed with a step at 68 which forms a valve with the O-ring 69 on the stem 62. A spring 79 is interposed in the bore 63 and arranged to bias the piston portion 66 outwardly. This provides for iiuid flow in either direction desired between the cavities and 66 through a hole 71 drilled through the piston portion 6i) and cross drilled holes 72 opening behind the ring 69. An O-ring 74 is also formed on the stem to prevent escape of the fluid therepast.

When the hydraulic system is pressurized after bleeding there is a greater area of the piston portion 69 exposed to the chamber 65 than there is exposed to the bore 63. Accordingly, a differential force is developed which closes the separate members of the piston 55 together thereby sealing the piston after which it acts as a single piston. A set screw 75 cooperates with a groove 76 to limit the movement of the portion 69.

The gear capsule 28 includes special locking and antibacklash provisions whereby the entire actuator 15 may be readily connected and disconnected from the splined shaft of a controller 12. Such a spline shaft is indicated at 89 in FIG. 5 and includes two axially aligned splined portions 81 and 82 separated by a radius S3. Governor input or control shafts are commonly formed with such an inner spline 81 and outer spline 82 to provide for the conventional locking of a split coupling thereon which commonly include a transverse rocking bolt received in the radius 83. This invention provides an improved coupling forming a part of the output gear of the actuator and includes quick disconnectable locking means connectable directly to such a shaft as well as internal automatic anti-backlash.

The rack 58 of the piston 55 is in continuous engagement with the peripheral teeth on a cup-shaped output gear 85 forming the main portion of the capsule 23. The gear 85 is rotatably received within the bearing 39 and supports a spring retainer cap 8S which is, in turn, rotatably received within the bearing 36. The cap S3 is secured to the gear 85 by means of a plurality of machine screws 89.

The views of the capsule comprising FIGS. 7-9 are looking into the interior of the gear 85 with the spring retainer cap 88 removed. The gear S5 includes a spline connection at 90 (FIG. 5) which is arranged and proportioned to engage the inner spline portion S1 of the shaft 89. A pair of pins 92 and 93 extend in a generally axial direction from the back wall of the gear 85 and are arranged in diametrically opposed 180 locations on opposite sides of the spline portion 90.

The pins 92 and 93 pivotally support a pair of locking arms or cams 95 and 96 which may be of identical construction to each other, as best shown in FIGS. 7 and 9, wherein they are shown respectively in a retracted position clear of the shaft S0. The cams are movable to an inner position in engagement with the radius 83 of the shaft, as shown in FIG. 9. The cams 95 and 96 comprise the spline locking means which are movable inwardly into locking engagement with the shaft 80 at the radius 83 and prevent the withdrawal of the shaft from the actuator 15 and the withdrawal of the actuator 15 from the controller 12.

A generally key-shaped spline-locking butterfly is also mounted on the pins 92 and 93 in superimposed relation over the cams 95 and 96, as shown in FIG. 8. The buttertiy 100 consists of a backlash-removing member and is formed with an internal spline 101 which is axially aligned for engagement with the outer spline portion S2 of the shaft 80 when the spline portion 90 of the gear 85 is engaged with the inner spline portion 81,

The pins 92 and 93 extend into aligned openings 105 formed in the butterfly 100. These openings are of slightly greater diameter than the cooperating pins which provides for limited angular locking movement of the buttertiy 100 as indicated at 106 in FIG. 11.

The locking of the butterfly 160 on the spline portion 82 is effected by the lingers 110 of an operator 112. The operator 112 is mounted for rotation within the capsule 28 with the ngers 110 extending inwardly as shown in FIG. 5. These fingers operate within opposite 45 radial recesses 113 formed in the opposite sides of the butterfiy 160 and also operate around the outer circumference of the cams 95 and 96 and serve to move the cams inwardly with clockwise rotation of the operator. As shown in FIG. 9, the fingers and the cams 95 and 96 do not form an interference fit but the ingers are free to move past the curve back surfaces of the earns until they come into engagement with the abutments 114 of the butterfly 109. In this manner, the fingers 110 can effect the limited anti-backlash rotation of the butteriiy 161) on the pins 92 and 93.

The locking position of the cams 95 and 96 and the clockwise or backlash eliminating position of the buttertiy 160 is maintained by an internal anti-backlash coil spring 115. The spring 115 is received over the stem 118 of the operator 112 and has one end engaged in a recess in the back of the operator and has the opposite end engaged within a suitable recess formed within the cap 88. The spring 115 is wound in tension and tends to rotate the fingers 110 of the operator 112 in the clockwise sense.

The stem 118 of the operator 112 extends through an opening 116 formed within the cap 88 and is supported for rotation at this opening. The stern 11S is formed with an internal driving hex 126 which is accessible through an access opening 121 lformed in the plate 30. Any suitable tool, such as the tool 125 having a hexagonal head 126, may be inserted into the stem of the operator 112 to rotate the operator in the counterclockwise sense against the force of the spring 115.

The operation of the mechanism within the gear capsule 28 will be described first since it is employed first in the engagement and removal of the actuator from a suitable splined shaft on a controller. A suitable tool, such as the tool 125, is inserted into the operator 112 and the operator is rotated in the counterclockwise sense and held in this position while the actuator 15 is positioned on the shaft, such as the shaft S0. In this position of the operator 112, the cams 95 and 96 are free to rnove outwardly into the position shown in FIGS. 7 and 8. The inner beveled edges of the cams provide their outward movement when the shaft 80 is inserted.

The shaft 80 is inserted until the end of the shaft bottoms on the inner surface of the operator 112. At this position, the spline portion 90 of the drive gear 85 is positioned on the inner spline section 81 of the gear 80, and the anti-backlash butterfly 100, which has its spline section 101 in alignment therewith, is engaged on the outer spline section 82 of the shaft.

The tool 125 is then released, and the spring 115 rotates the operator 112 and the fingers 110 in the clockwise sense. This movement first operates against the curved backs of the locking cams and moves the cams inwardly into engagement with the radius 83, as shown 93, it is biased in an anti-#backlash sense on the shaft 80.

The position of the fingers at this time is also shown in FIG. 9, and they form a lock against the outward or releasing movement of the cams 95 and 96, thereby locking the gear capsule 28 and the actuator 15 on the shaft in driving yrelation to the shaft 80. The radius rod 50 may then be connected to prevent the relative rotation of the actuator 15.

The hydraulic connections may then be made at 52 and 53 to the end blocks 42 and 43. It is necessary to purge the actuator of all air which may be entrapped therein, so that the piston 55 faithfully and accurately follows the position of the handle E17. This invention includes a simplified bleed arrangement by means of which `all of the air within the hyd-raulic portion of the actuator may be completely purged and removed. Any suitable pumping mechanism may be employed within the hydraulic lines 18 and 19 to pump uid through the actuator at substantially zero pressure, and then to cause the pressurization of the closed hydraulic circuit. One satisfactory such mechanism consists of a compensator which is sold as part number 15915 of Adel Precision Products Corporation, a-bove, and forms no part of the present invention.

Purging fluid is caused to oW in either direction through the actuator. For the purpose of illustration, it may be .assumed that the fluid enters through the inlet connection 52 and leaves through the connection 53. The two parts 60 and 55 of the piston 55 are pushed away from each other by the spring 70 and the hydraulic fluid ows from the chamber 65, through the axial passageway 71 within the piston portion 60, through the T passageway 72, and into the interior of the hollow piston member 56 and out the axial passageway 67 into the right-hand chamber 66 for liow through the passageway 51. In this manner, al1 of the ent-rapped air may be effectively purged.

The hydraulic system is then pressurized by a suitable compensator unit such as described above in the manner well known in the art. The member 60 has a greater area exposed to the chamber y65 than Vit does to the interior of the piston member 55. During pressurization, the member 60 will be forced lagainst the spring 70 to the right into the closed position shown in FIG. 3 which has the effect of seating the O-ring 69 in the bore 63. In this closed position, each end of the .piston 55 is isolated from the other, and the parts of the piston move as a un1t.

The movement of the handle 17 is translated into `an equivalent movement of the piston 55 within the cylinder liner 40. Preferably, the piston 55 is formed with a clearance t within the liner 40 and the pressurization causes the expansion of the V-block rings 64 therelby tending to hold the rack 58 into engagement with the piece of the output gear 85.

The position of movement may be indicated by a position indicating system including a sending 'unit 20 (FIG. 6) which is geared in driven engagement with the drive gear 85 through an anti-backlash gear 130. The unit 20 provides electrical position reference for the position indicator 21 within the control room. The anti-backlash gear 130 is fully described in applicants copending application Serial No. 104,435, led April 20, 1961, now Patent No. 3,153,989, and forms no part of this invention.

It .is therefore seen that this invention provides an actuator which may be readily attached and removed from the shaft of a jet engine throttle controller, and requires no other connection to the controller with the exception of the radius rod 50 which may make any suitable connection to prevent the rotation of the unit. In other words, the actuator 15 is totally wholly supported on the shaft which it actuates and positions. The actuator not only includes a gear capsule which provides convenient connection and disconnection to the shaft, but also provides `an Ianti-backlash connection.

As a matter of further convenience and simplification, the hydraulic piston is formed in two parts which are biased apart by a spring ,forming a valve and which move together when the unit is pressurized for subsequent operation. In the biased apart position, the two piston members lcomplete an internal piston passageway for the purging of the actuator of `all entrapped air. Thus, all external bleed lines and valves are eliminated in this invention.

While the form of -apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that this invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A hydraulic throttle actuator for positioning the splined rotatable shaft of a throttle and adapted for mounting directly on such shaft, comprising a body, a cylinder in said body, a two-way piston received in said cylinder and positionable axially therein in accordance with a desired throttle position, a rack gear on said piston, an output gear rotatably received in said body in driven relation to said rack gear and having means therein forming a spline connection arranged for direct mounting on such shaft in driving relation thereto and supporting said actuator thereon, a separate spline engaging backlash removing member having a spline portion axially aligned with said gear spline connection and movable angularly with respect to said output gear and also engageable with the spline shaft in axially spaced relation to said spline connection of said gear, and an externally accessible operator rotatably mounted on said output gear in axially aligned relation thereto having means thereon movable into engagement with said backlash removing member to urge said member in said angular sense for locking said actuator on said shaft, and spring means urging said operator into said engagement with said member.

2. A hydraulic throttle actuator for positioning the splined rotatable shaft of a throttle and adapted for mounting directly on said shaft, comprising a body, a cylinder in said body, a two-way piston received in said cylinder and positionable axially therein in accordance with a desired throttle position, a rack gear on said piston, an output gear capsule rotatably received in said body including an Voutput gear in driven relation to said rack gear and having means thereon forming a spline connection arranged for direct mounting on such shaft in driving relation thereto and supporting said actuator thereon, a separate spline engaging backlash removing member in said capsule having a spline portion axially aligned with said gear spline connection and movable angularly with respect to said output gear and also engageable with the spline shaft, a capsule cap enclosing said member and secured to said output gear, and an externally accessible operator rotatably mounted in said cap in axially aligned relation to s-aid output gear having means thereon movable into engagement with said backlash removing member to urge said member in said angular sense for locking said actuator on said shaft, and a coil spring in said capsule between said cap and said operator and connected to urge said operator into said engagement with said members.

3. An actuator adapted for simplified connection to and removal from a splined shaft and for support on such shaft wherein the shaft includes two axially aligned splined portions divided by a radius groove comprising, a body, power means in said body movable into selected positions, an output gear rotatably mounted in said body in driven relation with said power means, said gear being generally cup-shaped and having an internally splined portion adapted to receive said shaft on the inner spline portion thereof, a backlash removing spline member received within the cup of said gear and engageable with said outer spline portion of said shaft, a movable locking cam positioned in the cup of said gear between said spline portion and said member and mounted on said gear for movement between an outer position clear of the shaft and an inner position engageable with said radius groove, and a spring biased operator mounted on said gear having a finger thereon engageable with the member to urge said member angularly into blacklash eliminating engagement with such shaft and further engageable with said cam to move said cam into its inner position and preventing movement thereof into said outer position.

4. A hydraulic actuator adapted for direct connection to a driven shaft which has inner and outer spline portions separated by a radius groove, comprising an output shaft in said actuator having means thereon forming a driving spline connection engagable with such driven shaft at said inner spline portion, a separate backlashremoving member having a spline connection formed thereon and being axially aligned with said driving spline and engagable with such driven shaft at the outer spline portion thereof, means mounting said member for limited angular movement with respect to said output shaft, an operator mounted for angular movement with respect to said output shaft between an operative position in engagement with said member urging said member angularly with respect to said output shaft into backlash removing engagement with the outer spline portion of the driven shaft and also being movable out of engagement with said member into a retracted position, spring means urging said operator into said operative position with said member, a locking cam having an inner surface engageable with the driven shaft at such groove, means mounting said locking cam for movement between a retracted position clear of the driven shaft and an inner position in which said surface thereof is received in the shaft groove, and means on said operator engageable with said cam in the retracted positions of said oper- 40 ator and said cam to move said cam into said inner position thereof concurrently with the engagement of said operator with said backlash removing member.

5. A hydraulic throttle actuator for positioning a splined rotatable shaft of `a throttle in which the splined shaft is formed with a radius for facilitating attachment of a driven shaft thereto, comprising a body, a cylinder in said body, a piston received in said cylinder and positionable axially therein in accordance with a desired throttle position, a rack gear on said piston, an output gear rotatably received in said body in driven relation to said rack gear and having means thereon forming a spline connection adapted for mounting on such shaft in driven relation thereto and for supporting said actuator thereon, a separate spline-engaging backlash-removing member having a spline connection portion engagable with the spline shaft in axially spaced relation to said spline connection of said output gear thereon, means mounting said member for angular movement with respect to said output gear, a pair of arcuately shaped locking cams positioned generally on opposite sides of such shaft, means on said gear pivotally mounting said cams in opposed relation to each other for movement between a retracted position radialy clear of such shaft and an inner position in engagement with the shaft radius, and an operator rotatably mounted on said gear and having means thereon movable into engagement with said locking cams and said backlash-removing member urging said cams inwardly into said inner position thereof and urging said member in an angular sense for eliminating backlash between said ouput gear and said throttle shaft.

References Cited by the Examiner UNITED STATES PATENTS 1,474,153 11/1923 Klein 287-53 1,828,305 10/1931 Zeder et al 74-440 X 2,250,369 7/1941 Gorton 74--440 X 3,040,717 6/1962 Rumsey 74-91 X 3,090,641 5/1963 Eminger 74-440 X FOREIGN PATENTS 1,199,375 12/ 1959 France.

BROUGHTON G. DURHAM, Primary Examiner.

Claims (1)

1. A HYDRAULIC THROTTLE ACTUATOR FOR POSITIONING THE SPLINED ROTATABLE SHAFT OF A THROTTLE AND ADAPTED FOR MOUNTING DIRECTLY ON SUCH SHAFT, COMPRISING A BODY, A CYLINDER IN SAID BODY, A TWO-WAY PISTON RECEIVED IN SAID CYLINDER AND POSITIONABLE AXIALLY THEREIN IN ACCORDANCE WITH A DESIRED THROTTLE POSITION, A RACK GEAR ON SAID PISTON, AN OUTPUT GEAR ROTATABLY RECEIVED IN SAID BODY IN DRIVEN RELATION TO SAID RACK GEAR AD HAVING MEANS THEREIN FORMING A SPLINE CONNECTION ARRANGED FOR DIRECT MOUNTING ON SUCH SHAFT IN DRIVING RELATION THERETO AND SUPPORTING SAID ACTUATOR THEREON, A SEPARATE SPLINE ENGAGING BACKLASH REMOVING MEMBER HAVING A SPLINE PORTION AXIALLY ALIGNED WITH SAID GEAR SPLINE CONNECTION AND MOVABLE ANGULARLY WITH RESPECT TO SAID OUTPUT GEAR AND

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