JP2944728B2 - Pressure compensated rotary hydraulic device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary hydraulic device, and more particularly, to a pressure compensation type rotary pump in which a centrifugal pump and a vane pump are combined.

[Conventional technology]

2. Description of the Related Art Positive displacement pumps are conventionally used as fuel pumps for aircraft turbine engines in order to obtain sufficient fuel pressure under low-speed starting conditions. In recent years, the need to improve pump reliability and overall package size and weight has increased the need to employ centrifugal pumps in this type of application. However, since centrifugal hydraulic pumps rely on high speed rotation to obtain high pressure discharge, sufficient fuel pressure is required in the speed range of about 10 to 15% to allow the engine to start. Not bring.

According to a typical system design specification, a fuel pump has a specific flow rate at which the gas / liquid suction rate is 0.45 and an effective suction pressure or NPSP which is at or above the true vapor pressure of the fuel at the pump suction. It is required to operate at 34.5 kPa (5 psi). However, newer system specifications require the ability to have a gas / liquid suction rate of 0.45 over a wider engine flow range and involve intermittent all-liquid or all-gas operation.
A gas / liquid suction rate of 0 may even be required. In addition, the requirements for NPSP have been increased to 34.5 kPa (5 psi) over the entire engine flow range, and in some cases 20.1 kPa (3 psi) may be required over the entire engine flow range.

[Problems to be solved by the invention]

Accordingly, a general object of the present invention is to provide a centrifugal pump with the desirable features of reliability, overall package size and weight, while still having sufficient features for use in low speed starting of turbine engines in aircraft and other similar applications. An object of the present invention is to provide a rotary hydraulic device of the type described above that provides a proper discharge pressure.

It is another object of the present invention to provide a rotary hydraulic pump capable of satisfying flow conditions in an aircraft turbine engine fuel delivery system over a wide engine operating range. It is another object of the present invention to provide a fuel pump as described above, which is economical and structurally efficient in terms of severe weight and volume requirements in aircraft applications and has a reliable service over a long operating life. Is to provide something that provides.

[Means for solving the problem]

Briefly, the present invention is a rotary hydraulic system that has particular utility as a fuel pump for an aircraft turbine engine, combining the desirable features of similar vane and centrifugal systems, That is, it is intended to have improved reliability, package size and weight coupled with high pressure volume displacement at low speeds. This, according to a presently preferred embodiment of the present invention, functions as a single rope pressure compensated vane pump for engine starting,
This is achieved by providing a combined vane and centrifugal pump configured to function as a centrifugal pump at normal operating speeds.

In accordance with a first important aspect of the present invention, a hydraulically compensated rotary hydraulic device includes a housing, a rotor having a plurality of radially extending peripheral slots and provided for rotation within the housing, and an individual within the slot. And a plurality of vanes slidably provided on the upper surface. An annular race ring is provided in the housing and defines a radially inwardly directed vane race surrounding the rotor and a fluid pressure cavity between the race and the rotor periphery. A fluid suction passage and a discharge passage of the housing are connected to the cavity. The housing carries a spring actuator which engages a track ring and biases the ring to a position eccentric with respect to the axis of rotation of the rotor. At a location diametrically opposite the spring actuator, a fluid actuator is provided within the housing and is coaxial with the rotor against the force of the spring actuator in response to fluid pressure in one of the suction or discharge passages. Move the orbital ring to a new position. Thus, the fluid actuator controls the displacement of the device as a function of the fluid pressure. In a preferred application of the device of the present invention, a rotary hydraulic pump, the fluid actuator is connected to the discharge of the pump, and the orbital ring is coaxial with the rotor and the pump is driven up to a pressure limit where the displacement of the pump is zero. As the discharge pressure increases, the displacement of the pump decreases.

According to a second important aspect of the invention, the rotor includes a plurality of internal passages extending radially from an open outer end around the rotor between the base slots to an inner end for receiving suction fluid. . The track ring has a plurality of radial passages extending therethrough, preferably at an angle to the axis of rotation of the rotor. Thus, in the zero displacement position where the race ring is coaxial with the rotor, the device acts as a centrifugal device, in which case the rotor vanes function to seal the rotor discharge from the rotor suction. The orbital ring acts as a diffuser. In a preferred embodiment of the present invention as a fuel pump for an aircraft turbine engine, the shaft of the pump extends from the housing of the rotor and connects to a power source, and the suction of fuel is coaxial with the shaft of the pump and opposite to the rotor. Placed on the side. A helical fuel inducer is connected to the drive shaft of the pump in the suction and pressurizes the suction fluid into the internal passage of the roller and then into the fluid pressure cavity between the rotor and the race ring. This pre-pressurization of the fluid helps to bias the rotor vanes into sliding sealing engagement with the race ring and side backup plates, and also helps to obtain high fluid pressure when the pump is slow. help.

〔Example〕

The invention, together with additional objects, features and advantages thereof, will be best understood from the following detailed description, the appended claims and the accompanying drawings.

The accompanying drawings show a fuel pump 10 for an aircraft engine according to a presently preferred embodiment of the present invention, which is a hollow cup-shaped enclosure having a base 16 and outwardly stepped side walls 18. That is, the housing 12 is formed by the outer casing 14. A drive shaft 20 protrudes from the base 16 coaxially with the outer casing 14, and a disk-shaped pump rotor 22 is formed integrally therewith. Rear backup plate
24 is fixed to the open end of the outer casing 14 by bolts 26. The front backup plate 28 is slidably disposed in the outer casing 14 so as to face the rear backup plate 24, and a base portion of the front backup plate 28 and the outer casing 14.
The preload spring 30 disposed between the springs 16 elastically biases the rear backup plate 24. The periphery of the front backup plate 28 is stepped similarly to the outer casing surrounding it, and is slidably sealed with respect to this by a plurality of O-rings 32. Similarly, the rear backup plate 24 is sealed to the outer casing 14 by an O-ring 34. A pump mounting flange 36 projects radially outward from the base 16 of the outer casing 14 coaxially with the rotation axis of the drive shaft 20. A shaft seal 38 held on the base 16 of the outer casing cooperates with a ring 40 on the drive shaft 20 associated therewith to seal a shaft opening passing through the outer casing 14.

A front port plate 42 is secured to the backup plate 28 by appropriate pins (not shown).
A complementary rear port plate 44 is secured to the rear backup plate 24. The port plates 42 and 44 are parallel to each other and slidably engaged with the parallel side surfaces of the rotor 22. As described later, the port plates 42 and 44 are provided in the cavity between the spring 30, the front backup plate 28, and The port plate 42 is elastically urged against the facing rotor side surface by the fluid pressure of
Is being urged towards. The rotor 22 includes a plurality of radially extending slots 46 arranged in rows around its periphery.
have. A flat, generally rectangular vane 48 is slidably disposed within each slot 46. Each slot
At the radially inner end of 46 is formed a lower vane chamber 50 for supplying fluid pressure, the radius of which from the axis of rotation of the rotor 20 corresponds to a kidney-shaped slot in the port plates 42,44. It corresponds to the distance to be aligned with the circumferential rows of 52,53. A fluid passageway 54 (FIG. 1) in the front backup plate 28 connects the slot 52 to an annular cavity 56 between the front backup plate 28 and the outer casing 14 to transfer intermediate pressure fluid to the vane lower chamber 50. To bias the vanes 48 radially outward of the rotor 22. Similarly, a fluid passageway (not shown) in the front backup plate 28 connects the slot 53 (FIG. 3) to a fluid discharge to deliver discharge pressure fluid to the vane lower chamber.

Inside the rotor 22, a plurality of radially extending rotor passages 60 are formed in uniform circumferential rows, and as best shown in FIG. It is located midway between a pair of adjacent slots 46. The outer end of each rotor passage 60 is expanded outward and opens around the roller 22. The radially inner end of each rotor passage 60 opens into an axial passage 62 extending through the entire rotor body. The axial passage 62 alternately aligns with the slots 64, 65 (FIGS. 1 and 3) of the port plates 42, 44 as the rotor rotates. Slot 65 is key-shaped, while slot 64 is liver-shaped. The slot 65 is connected to the base 16 of the outer casing 14 through the passage 67 of the front backup plate 28.
Annular cavity 66 surrounding drive shaft 20 adjacent to
And pumps fluid at suction pressure into the annular cavity 66, thereby assisting the preload spring 30 to bias the front backup plate 28 against the rotor 22. Another passage 68 in the front backup plate 28 connects the slot 64 with the annular cavity 56 to supply intermediate pressure fluid to the lower vane chamber 50 as described above. Yet another passage 70 connects the slot 64 of the port plate 42 to a further annular cavity 72 between the front backup plate 28 and the outer casing 14. As observed in FIG.
The annular cavities 72, 56 and 66 are mutually sealed by the O-ring 32. A circumferential row of passages 74 extend radially inward from the axial passages 62 of the rotor 22 to interconnect the rotor passages 60 with the hollow interior 76 of the drive shaft 20.

An annular track ring 78, which is a part piece, is held between the port plates 42 and 44, and surrounds the periphery of the rotor 22. The track ring 78 is free to slide in a direction transverse to the axis of rotation of the rotor 22, and to guide and limit this transverse movement, the ledges on both sides of the outer casing 14 are provided.
It has diametrically opposed flats 80 (FIG. 2) which cooperate with 82. A plurality of passages 84 are formed in the race ring 78, each passage 84 expanding outward from the body of the race ring and arranged at an angle to the diameter of the race ring. Have been. The spring actuator 86 (FIG. 2) has a connecting ring 88 integral with the side wall 18 of the outer casing 14 and a radial through passage 90 extending through the connecting ring. A cup-shaped piston 92 has a side wall slidably retained within the through passage 90 and a base connected by a sealing vane 94 to the facing peripheral surface of the orbital ring 78. A cup-shaped spring seat 96 is adjustably threaded into the outer end of the through passageway 90 to hold the coil spring 98 in compression between the spring seat 96 and the piston 92. Guide pin 10
0 is a base held between the coil spring 98 and the spring seat 96,
A body extending coaxially through the coil spring 98 to limit lateral movement of the coil spring.

The fluid actuator 102 (FIG. 2) has a hollow through passage 105 that is integral with the outer casing 14 and has a radial through passage 105 that is diametrically aligned with the passage 90 of the splice 88 with respect to the axis of rotation of the rotor 22. The connecting ring 104 is formed. A hollow cup-shaped sleeve 106 is screwed into the through passage 105 in an adjustable manner. A fluid piston 108 is slidably held at the inner end of the sleeve 106, and a track ring 78 facing diametrically opposite the sealing vane 94 of the spring actuator 86.
Are connected to each other by a sealing vane 110. The internal stopper 111 in the sleeve 106 is the fluid piston 10
Cooperating with 8 limits the outward movement of the fluid piston, thereby limiting the eccentric movement of the orbital ring 78 with respect to the rotor 22 under the force of the spring actuator 86. A pair of diametrically opposed cavities 122 between the race ring 78 and the outer casing 14 are coupled to the annular cavity 72 and are provided by passages 70 with the lower vane chamber 50 of the rotor.
Is linked to Another pair of diametrically opposed cavities 112 between the orbital ring 78 and the outer casing 14 include channels (not shown) in the rear backup plate 24.
Are interconnected by a pressurized fluid
It is sent to the control mechanism via 116. Passageway 116 extends from this channel into collar 104 into cavity 112 and sleeve
The pressurized fluid extending through the through opening 118 in 106 to the hollow interior of the collar 104 and thus in the cavity 112 is supplied to the fluid actuator 102 and acts on the fluid piston 108 of the actuator. Annular opening 12 in sleeve 106
0 is released by the movement of the fluid piston 108 to supply fluid from the fluid actuator 102 to a pump filter and a pump discharge port (not shown). The open connecting ring 124 of the rear backup plate 24 forms a pump fluid suction for the drive shaft 20 and the drive shaft. Inducer 126
Is a substantially cylindrical body 1 threaded coaxially with the drive shaft 20 and disposed within a suction open splice 124.
Consists of 28. A series of spiral vanes 130 are used to open the connecting ring 124
Projecting radially from the body 128 until adjacent to the inner diameter of the body.

[Action]

In operation, when the pump is initially at rest, the orbital ring 78 is moved by the spring actuator 86 to a second position.
The piston is biased in the upper right direction as viewed in the figure, so that the fluid piston abuts against the stopper 111 and the orbital ring 78 is eccentric with respect to the rotor 22. Thus rotor 22
Between the orbital ring 78 and a radially inner side of the fluid actuator 102, a kidney-shaped fluid pressure cavity is formed,
Thus, the rotor 22 and the axial ring effectively constitute a single lobe vane pump. During the first rotation of the drive shaft 20, the suction fluid at the point of the open connecting ring 124 is pre-pressurized by the rotation of the inducer 126.
The pre-pressurized fluid flows through the slot 65 and the axial passage 6
2. It is supplied to the annular cavity 66 through the passage 67, and urges the front backup plate 28 toward the rotor 22. The pre-pressurized fluid is also applied to rotor 22 and track ring 78
Radially outwardly through the axial passage 62 and the rotor passage 60 into the fluid pressure cavity formed therebetween. Vane 48 engages the facing track ring surface,
This surface will effectively form a vane trajectory. During lift of the vane in operation in this vane pump mode, the lower vane chamber 50 is
It will be appreciated that it is connected to the low pressure side via an annular cavity 56 and to the discharge side of the pump by a slot 53 during processing of the vane. Thus, the vane-like action of the vane helps boost the pump discharge pressure during operation in this vane pump mode. Pressurized fluid from a positive displacement single lobe vane pump under the action of this vane is pumped by a passage (not shown) to the annular opening 120 and from the pump filter to the pump discharge. This continues until approximately 10% of the nominal operating speed N (FIG. 4).

As the pump speed increases and the fluid discharge pressure due to centrifugal force increases in response, the fluid piston 108 is urged by the fluid pressure to move the orbital ring 78 against the rotor 22 against the force of the spring actuator 86. Move to a position that is concentric with. Thus, the stroke of the vane 48 communicating through the slots 52 and 53 is reduced, and the displacement of the pump is accordingly reduced.

Meanwhile, as the rotor speed increases, the effective discharge pressure of the centrifugal pump increases accordingly. Design speed N
(FIG. 4), the rotor 22 functions as a two-stage impeller. In the first stage, inducer 12
Fluid from 6 to the slot 64 in the port plate is pumped around the rotor by the action of centrifugal force and from there to the cavity 122 leading to the annular cavity 72 through the diffuser passage 84. This first stage impeller discharge is at intermediate pressure and is slotted by passage 70
It is returned to 65 and is fed by centrifugal force by this rotor 22 again performing the impeller action. Thus the rotor passage 60
And the axial passage 62 is provided with slots 64, 65 of the port plate.
And cooperates with the passages 70 in the backup plate to alternately function as first and second stage impeller passages as the rotor rotates. In addition, passage 74 in drive shaft 20 directs intermediate pressure fluid to axial passage 62, which is aligned with slot 65 in the port plate, thereby directing the first stage fluid flow to impeller or rotor 22. Functions as a sending injector.

FIG. 4 shows the effective discharge pressure 150 of the vane pump for the required engine pressure, regulated by a pressure control valve (not shown), the displacement 152 of the vane pump controlled by the fluid piston 108, and the rotor (impeller). )
Discharge pressure 154 of the centrifugal pump determined by the speed of
5 is a graph showing the sum of pump discharge pressures 156, all as a function of pump speed (rpm). At a speed threshold 158, the sum of the discharge fluid pressures is
Sufficient to overcome the force of the spring actuator 86 at 102 and position the orbital ring 78 coaxially with the rotor 22 so that the displacement volume 152 and the effective discharge pressure 150 of the vane pump are zero.

〔The invention's effect〕

As described above, according to the present invention, the desirable features of the vane type device and the centrifugal type device having similar properties are combined, and the device functions as a high-pressure positive displacement device at a low speed, and has improved reliability and improved packaging. A rotary hydraulic device is provided that is particularly useful as a fuel pump for an aircraft turbine engine, having the characteristics of a centrifugal device in size and weight. And, as noted above, according to a presently preferred embodiment of the present invention, it is configured to function as a pressure compensated single lobe vane pump at engine startup and as a centrifugal pump at normal operating speeds. It is also achieved by providing a combined vane and centrifugal pump.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side elevation view of a rotary hydraulic apparatus according to a presently preferred embodiment of the present invention; FIGS. 2 and 3 are substantially the first 2-2 line and 3-line.
FIG. 4 is a cross-sectional view taken along each of three lines; FIG. 4 is a graphical diagram useful in explaining the operation of the present invention. 10 ... Fuel pump, 12 ... Housing 20 ... Drive shaft, 22 ... Rotor 24 ... Rear backup plate 28 ... Front backup plate 42,44 ... Port plate, 46 ... Slot 48 ... Vane, 50: Vane lower chamber 52, 53: Slot, 60: Rotor passage 62: Axial passage, 64, 65: Slot 78: Track ring, 84: Passage 86: Spring actuator, 90: Through passage 92 Piston 96 Spring seat 98 Coil spring 100 Guide pin 102 Fluid actuator 105 Through passage 106 Sleeve 108 Fluid piston 111 Internal stopper 126 …… Inducer

Claims (22)

(57) [Claims] 1. A housing (12) and a rotor (22) having a plurality of radially centrifuging slots (46) therearound and provided to rotate within said housing.
A plurality of vanes (48) individually slidably provided in the slots; a radially inward vane track means provided in the housing and surrounding the rotor (22); A pressure compensated rotary hydraulic device comprising: an annular race ring (78) forming a fluid pressure cavity between rotors; and a fluid suction passage and a discharge passage means of said housing connected to said cavity. Spring means (86) retained by the housing for biasing the raceway ring to an eccentric position with respect to the rotor; coupled to the raceway means for applying the raceway ring to the force of the spring means; Responsive to the fluid pressure of one of the fluid suction passage and the discharge passage means to move the same toward a position coaxial with the rotor, and displacing the displacement volume of the device through the passageway. Fluid actuator means (102) for controlling as a function of fluid pressure in one of the stages, further comprising said rotor (22) extending from an open outer end to an inner end around said rotor between each pair of said vanes. A plurality of radially oriented internal passages (60) and passage means (64, 65) in said housing for supplying suction fluid to at least some of said inner ends. 2. The spring means (86) includes a first piston (92) radially slidably mounted within the housing and connected to the track ring, and a radially oriented shaft. The apparatus of claim 1, comprising a spring actuator having a coil spring (98) having a compression seat held between a spring seat in the housing and the first piston. 3. The apparatus of claim 2 wherein said housing includes means for radially positioning and adjusting said spring seat within said housing. 4. The first piston (92) wherein said spring means (86) includes a radial passage (90) in said housing.
Is slidably received in said passageway and said spring seat comprises means (96) threadably adjustably threaded radially outwardly of said first piston into said housing. apparatus. 5. The spring seat further includes a coil spring (9).
5. The device of claim 4, including a spring guide pin (100) telescopically received in (8). 6. A first piston (92) having a base connected to said raceway ring and a cylindrical outer side slidably received in said passageway (90) and receiving said coil spring therein. 6. The apparatus of claim 5, comprising an open cup shaped piston having a side wall. 7. The fluid actuator means (102)
3. A hydraulic fluid actuator comprising a second piston (108) slidably mounted on said housing in a radial direction and coupled to said raceway ring on a diametrically opposite side of said first piston. apparatus. 8. A radial passageway (105) in said housing for slidably receiving said second piston therein, said fluid actuator (102) being received in said passageway. Means for defining a seat that limits radial outward movement of said second piston. 9. The apparatus of claim 8, wherein said fluid actuator (102) further includes means (106) for adjustably positioning said seat in said passage. 10. The fluid actuator (102) includes a hollow cup-shaped sleeve (106) adjustably threaded into the passage and an opening in a side of the sleeve for receiving fluid from one of the passage means. 10. The apparatus of claim 9, including a second piston (108) slidably held by the sleeve (106) and the seat (111) integrally formed inside the sleeve. 11. The apparatus of claim 1, wherein said rotor (22) further includes internal passage means (62) interconnecting all of said inner ends. 12. The apparatus of claim 11, wherein said discharge passage means includes a radially angled passage extending through said track ring. 13. A housing, and a rotor arranged to rotate within the housing, the rotor having a plurality of radially extending peripheral slots between the outer and inner ends of the periphery of the rotor. A rotor having a plurality of internal passages extending in a direction, a plurality of vanes individually slidably provided in the slots, an annular orbital ring provided in the housing, and A radially inner surface surrounding the rotor to form a fluid pressure cavity therebetween;
Having a plurality of radial passages extending through the ring; fluid suction means in the housing for supplying suction fluid to the inner end of the rotor passage; and radially outward of the passage in the ring. A combined centrifugal and vane rotary hydraulic device comprising: a fluid discharge means including a discharge cavity of the housing; and a means for biasing the vane radially outward to slidably engage the ring. Means coupled to the ring to adjustably position the ring within the housing in response to fluid pressure of one of the suction means and the discharge means, and to control displacement of the device as a function of fluid pressure. An apparatus characterized by the above. 14. The housing of claim 1 wherein said spring means has a first piston radially slidably mounted within said housing and coupled to said track ring and having a radially oriented axis. 14. The apparatus of claim 13, comprising a spring actuator including a coil spring held in compression between a spring seat and said first piston. 15. A hydraulic fluid, wherein the fluid actuator means includes a second piston slidably mounted in the housing radially and connected to the raceway ring on a diametrically opposite side of the first piston. 15. The device of claim 14, comprising an actuator. 16. The system according to claim 16, wherein said housing includes opposed backup plate means including port means in face-to-face engagement with said rotor, said ring being movably disposed surrounding said rotor between said backup plate means. 14. The device of claim 13, wherein 17. The means for biasing the vanes comprises a fluid chamber at a radially inner end of each of the slots below the associated vane, and means within the port means for supplying fluid to the chamber. 17. The device of claim 16, wherein the device comprises: 18. The apparatus of claim 17, wherein said passage of said ring is angled radially of said rotor. 19. The apparatus of claim 18, wherein said slots and said passages of said rotor are alternately spaced from one another at equal intervals in a circumferential direction of said rotor. 20. A pump having a shaft connected to said rotor and extending from said housing through one of said backup means and having a fluid suction coaxial with said shaft and on the other of said backup means. Equipment. 21. The apparatus of claim 20, wherein said rotor includes a suction passage for supplying fluid from said suction to said inner end of said radial passage. 22. The apparatus of claim 21, further comprising a helical inducer connected to said shaft and disposed at said suction to pressurize fluid at said suction.