JPH04116282A - Pressure compensation type rotary hydraulic device - Google Patents

Abstract

PURPOSE: To secure a discharge pressure sufficient for the start of a turbine engine at a low speed and for similar applications by installing a hydraulic actuator which responds to a fluid pressure so as to move a bearing ring and controls the displacement capacity as a function of the fluid pressure. CONSTITUTION: Suction and discharge passages of a housing 12 are connected to a cavity 112. A spring actuator 86 is held in this housing 12, engaging with a bearing ring 78, and this ring 78 is energized to an eccentric position with the turning shaft of a rotor 22. At the position of a diametral opposite side to the spring actuator 86, a hydraulic actuator 102 is installed in the housing 12, and in response to the fluid pressure in one side of the suction passage or the discharge passage, the bearing ring 78 is moved toward concentric position with the rotor 22 against the force of the spring actuator 86. Thus, the hydraulic actuator 102 controls the displacement capacity of a device as a function of the fluid pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary hydraulic system, and more particularly to a pressure-compensated rotary pump that is a combination of a centrifugal pump and a vane pump.

BACKGROUND OF THE INVENTION Positive displacement pumps have traditionally been used as fuel pumps for aircraft turbine engines to provide sufficient fuel pressure under low speed starting conditions. In recent years, the need to employ centrifugal pumps in these types of applications has increased due to the desire to improve pump reliability and overall pancage size and weight. however,
Since centrifugal hydraulic pumps rely on high speed rotation to achieve high pressure delivery, sufficient fuel pressure is required in the 10 to 15 percent speed range to enable engine starting. does not bring about

According to typical system design usage, the fuel pump has a specific flow rate with a gas/liquid suction ratio of 0.45 and an effective suction pressure ratio that is greater than or equal to the true vapor pressure of the fuel at the pump suction. That is, NPSP is 34.5kPa
(5 pS i) is required. However, newer system usage requires the ability to have a gas/liquid intake ratio of 0.45 over a wider engine flow range, and a gas/liquid intake ratio of 1.0 with intermittent all-liquid or all-gas operation. A liquid suction rate may even be required. Furthermore, the requirement for NPSP is also 34.5k over the entire flow range of the engine.
Pa (5 ps i), and in some cases up to 20 ps i over the entire flow range of the engine.
．． 1 kPa (3 psi) may be required.

[Problem to be solved by the invention]

It is therefore a general object of the present invention to provide a centrifugal pump for use in low speed starting of aircraft turbine engines and other similar applications while retaining the desirable characteristics of centrifugal pumps with respect to reliability, overall package size and weight. It is an object of the present invention to provide a low-pressure hydraulic system of the type described above, which provides sufficient discharge pressure.

Another object of the invention is to provide a rotary hydraulic pump that is capable of meeting the flow requirements of an aircraft turbine engine fuel delivery system over a wide range of engine operation. Another object of the invention is to provide a fuel pump as described above, which is economical and structurally efficient with respect to the severe weight and volume requirements of aircraft applications, and which provides reliable service over a long operating life. It is to provide something that provides

[Means to solve the problem]

Briefly, the present invention is a low-pressure hydraulic system having particular utility as a fuel pump for aircraft turbine engines, which combines the desirable features of vane-type and centrifugal-type systems of similar nature. That is, it is intended to have improved reliability, package size and weight combined with high pressure volume displacement at low speeds. This, in accordance with a presently preferred embodiment of the invention, provides a combination vane and centrifugal pump configured to function as a single lobe pressure compensated vane pump for engine starting and as a centrifugal pump at normal operating speeds. This is achieved by providing a pump.

According to a first important aspect of the invention, a pressure-compensated rotary hydraulic system includes a housing, a rotor having a plurality of radially extending circumferential slots and arranged for rotation within the housing, and a rotor having a plurality of radially extending circumferential slots, each rotor having a plurality of radially extending circumferential slots. It consists of multiple vanes installed on a sliding shaft. An annular track ring is provided within the housing and defines a radially inwardly directed vane track surrounding the rotor and a fluid pressure cavity between the track and the rotor periphery. A fluid intake passage and a discharge passage of the housing are connected to the cavity. A spring actuator is carried by the housing and engages the raceway ring to bias the ring into a position eccentric to the axis of rotation of the rotor. Diametrically opposite the spring actuator, a fluid actuator is provided within the housing and responsive to fluid pressure in one of the suction or discharge passages to coaxially move the rotor against the force of the spring actuator. Move the orbital ring toward the desired position. The fluid actuator thus controls the displacement of the device as a function of fluid pressure. In a preferred application of the device of the invention as a rotary hydraulic pump, the fluid actuator is coupled to the pump discharge until the orbital ring is coaxial with the rotor and the pump reaches a pressure limit at which 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 between the vane slots from an open outer end around the rotor to an inner end for receiving suction fluid. , the orbital ring has a plurality of radial passages extending through the ring, preferably at an angle to the axis of rotation of the rotor.

Therefore, in the zero displacement position, where the drive ring is coaxial with the rotor, the device acts as a centrifugal device, with the rotor vanes acting to seal the rotor discharge from the rotor suction. , the orbital ring functions as a differential user. In a preferred embodiment of the invention as a fuel pump for an aircraft turbine engine, the pump shaft extends from the rotor housing and connects to the power source, and the fuel intake is coaxial with the pump shaft and opposite the rotor. placed on the side. A helical fuel inducer is connected within the suction to the drive shaft of the pump to pressurize and deliver suction fluid to the internal passage of the rotor and then to a fluid pressure cavity between the rotor and the raceway ring. This fluid prepressurization helps bias the rotor vanes into sliding sealing engagement with the raceway ring and side backup plates, and also helps the pump achieve high fluid pressure at low speeds. .

〔Example〕

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

In the accompanying drawings, there is shown a fuel pump 10 for an aircraft engine according to a presently preferred embodiment of the invention, which comprises a hollow cup-shaped enclosure having a base 16 and outwardly stepped side walls 18. , that is, it consists of a housing 12 formed by an outer casing 14. From the base 16 is the drive shaft 2.
0 protrudes coaxially with the outer case 14, and a disk-shaped pump rotor 22 is formed integrally therewith. A rear backup plate 24 is secured to the open end of the outer casing 14 by bolts 26. Front backup plate 2
8 is slidably disposed within the outer casing 14 opposite the rear back-up plate 24, and the rear back-up plate 2
It is elastically biased toward 4. The periphery of the front backup plate 28 is stepped, like the outer casing surrounding it, and is slidably sealed thereto by a plurality of o-rings 32. Similarly, the rear bank up plate 24 is sealed to the outer case 14 by an O-ring 34. For mounting the pump, a flange 36 integrally 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 with it to
Seal the sleeve opening through 4.

A front port plate 42 is secured to the front backup plate 28 by suitable pins (not shown). A complementary aft boat plate 44 is secured to the aft backup plate 24. Boat plate 42.
44 are mutually parallel and slidably engage the parallel sides of the rotor 22, and the fluid pressure in the cavity between the spring 30, the front buffer luff plate 28, and the outer casing 14 is controlled as described below. As a result, the boat plate 24 is elastically biased against the opposing side surfaces of the rotor, and the rotor is biased toward the boat plate 44. Rotor 22 has a plurality of radially extending slots 46 arranged in rows around its circumference. A flat, generally rectangular vane 4B is slidably disposed within each slot 46. The radially inner end of each slot 460 is formed with a lower vane chamber 50 for supplying fluid pressure, the radius of which from the axis of rotation of rotor 20 extends to the kidney-shaped end of boat plate 42.44. (thrower) 52.53 corresponds to the distance aligned with the circumferential row. Fluid passage 54 in front backup plate 2B
(FIG. 1) connects the slot 52 to an annular cavity 56 between this front back-up plate 28 and the outer housing 14 to supply intermediate pressure fluid to the lower vane chamber 50 to thereby cause the vane 48 to The rotor 22 is urged radially outward. Similarly, fluid passageways (not shown) in front backup plate 28 are connected to slots 53 (third
) is connected to a fluid outlet to deliver fluid at the outlet pressure to the vane lower chamber.

Inside the rotor 22, a plurality of radially extending rotor passages 60 are formed in a circumferential row.
As best shown in FIG.
is located midway between a pair of adjacent slots 46. The outer end of each rotor passage 60 flares outwardly and opens around the rotor 22. Each rotor passage 60
The radially inner end of the rotor body opens into an axial passageway 62 extending through the entire rotor body. Axial passages 62 alternately align with slots 64.65 (FIGS. 1 and 3) in boat plate 42.44 as the rotor rotates.

Slot 65 is key-shaped, while slot 64 is kidney-shaped. The slot 65 is the front backup plate 28
communicates via a passage 67 with an annular cavity 66 surrounding the drive shaft 20 adjacent to the base 16 of the envelope 14 for feeding fluid at suction pressure into the annular cavity 66;
Preload spring 30 thereby assists in biasing front backup plate 28 against rotor 22 . Another passage 68 in the front backup plate 28 is a slot 64
is connected to the annular cavity 56 to supply intermediate pressure fluid to the lower vane chamber 50 as described above.

A further passage 70 is provided in the slot 6 of the port plate 42.
4 into a further annular cavity 72 between the front bank amplifier plate 28 and the outer housing 14 . As observed in FIG. 1, the annular cavities 72.56 and 66 are sealed from each other by the O-ring 32. A circumferential row of passages 74 extend radially inwardly from the axial passage 62 of the rotor 22 and interconnect the rotor passage 60 with a hollow interior 76 of the drive shaft 20.

A one-piece annular track ring is held between the boat plates 42,44 and surrounds the periphery of the rotor 22. The track ring 78 is free to slide transversely to the axis of rotation of the rotor 22 and cooperates with shelves 82 on either side of the outer casing 14 to guide and limit this transverse movement. Flat portions 80 on both sides in the diametrical direction
(Figure 2). Raceway ring 78 has a plurality of passageways 84 formed therein, each passageway 84 extending outwardly from the body of the raceway ring and oriented at an angle to the diameter of the raceway ring. has been done. The spring actuator 86 (FIG. 2) is attached to the side wall 1 of the outer casing 14.
8 and a radial passageway 90 extending through the splice. A cup-shaped piston 92 has a side wall slidably retained within the passageway 90 and a base connected by a sealing vane 94 to the facing circumferential surface of the raceway ring 78 .

A cup-shaped spring seat 96 is adjustably threaded into the outer end of the through passageway 90 and holds a coil spring 98 in a compressed state between the spring seat 96 and the piston 92. Guide pin 100 has a base portion held between coil spring 9B and spring seat 96, and a body extending coaxially through coil spring 98 to limit lateral movement of the coil spring.

The fluid actuator 102 (FIG. 2) includes a radial passageway 10 integral with the housing 14 and diametrically aligned with a passageway 90 in the collar 86 with respect to the axis of rotation of the rotor 22.
It consists of a hollow collar 104 having a diameter of 5. A hollow cup-shaped sleeve 106 is screwed into the through passage 105 so that the sleeve 106 can be rotated. A fluid piston 108 is slidably held at the inner end of the sleeve 106 and is connected by a sealing vane 110 to the circumferential surface of the opposing raceway ring 78 diametrically opposite the sealing vane 94 of the spring actuator 86. has been done. Sleen 106
An internal stop 111 within cooperates with the fluid piston 108 to limit outward movement of the fluid piston, thereby causing the raceway ring 7 to move under the force of the spring actuator 860.
8 limits eccentric movement with respect to the rotor 22. A pair of diametrically opposed cavities 122 between the track ring 78 and the envelope 14 are coupled to the annular cavity 72 and are also connected by a passageway 70 to the rotor's undervane chamber 50 . Another pair of diametrically opposed cavities 112 between the track ring 78 and the outer housing 14 are interconnected by channels (not shown) in the rear back amplifier plate 24 and are pressurized. Fluid is delivered to the control mechanism via passageway 116. A passageway 116 extends from this channel into the collar 104.
Through opening 118 in cavity 112 and sleeve 106
Extending through the hollow interior of the collar 104, the pressurized fluid within the cavity 112 is thus supplied to the fluid actuator 102 and acts on the fluid piston 108 of the actuator. Annular frontage 120 of sleeve 106
is opened by movement of fluid piston 108 and supplies fluid from fluid actuator 102 to the pump filter and pump discharge boat (not shown). The open joint ring 124 of the rear backup plate 24 is connected to the drive shaft 2
0 and forms a coaxial pump fluid suction. The inducer 126 consists of a substantially cylindrical body 128 which is threaded coaxially to the drive shaft 20 and is disposed within a suction release collar 124 . A series of helical vanes 130 protrude radially integrally from the body 128 to abut the inner diameter of the open joint 124.

[Effect]

In operation, when the pump is initially at rest, the raceway ring 78 is biased by the spring actuator 86 in the upper right direction in FIG. 2, so that the fluid piston 108 abuts the stop 111 and the raceway Ring 78 is located eccentrically with respect to rotor 22. A kidney-shaped fluid pressure cavity is thus formed between the rotor 22 and the orbital ring 78 radially inwardly of the fluid actuator 102 such that the rotor 22 and the orbital ring effectively constitute a single-lobe vane pump. become. Upon the first rotation of the drive shaft 20, the open coupling ring 1
The suction fluid at point 24 is prepressurized by rotation of inducer 126 . This pre-pressurized fluid is supplied through slot 65 and axial passage 62 and passage 67 to annular cavity 66 to bias front backup plate 28 toward rotor 22 . Prepressurized fluid is also supplied radially outwardly through axial passage 62 and rotor passage 60 into a fluid pressure cavity formed between rotor 22 and raceway ring 78 . The vanes 48 engage the surfaces of the opposing track rings, which surfaces effectively form vane tracks. During vane ascent in this vane pump mode of operation, the vane lower chamber 50 is connected by slot 52 to the low pressure side via annular cavity 66, and during vane descent, the vane lower chamber 50 is connected to the low pressure side by slot 52. It will be understood that it is connected by 53 to the discharge side of the pump.

The piston-like action of the vanes thus helps boost the pump's discharge pressure during operation in this vane pump mode. The pressurized fluid delivered from the positive displacement single lobe vane pump under the action of this vane passes through the passage (
(not shown) into the annular opening 120 and from the pump filter to the pump discharge. This continues until approximately 10% of the nominal operating speed N is reached (FIG. 4).

As the pump speed increases and the centrifugal fluid delivery pressure increases correspondingly, the fluid piston 10B is biased by the fluid pressure and moves the raceway ring 78 toward the rotor 22 against the force of the spring actuator 86. Move it to a position concentric with . The stroke of the vanes 48 communicating through the slots 52 and 53 is thus 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. At about 60% of the design speed N (fourth time), the rotor 22 functions as a two-stage impeller. In the first stage, fluid from the inducer 126 to the port plate slot 64 is pumped by centrifugal force around the rotor and from there through the diffuser passage 84 into the annular cavity 72.
is sent to the cavity 122 connected to the.

The discharge of this first stage impeller is at intermediate pressure and is returned by the passage 70 to the slot 65 and centrifugally fed by this rotor 22 which again performs the impeller action. Thus, the rotor passage 60 and the axial passage 62 are
In cooperation with the port plate throwers 1-64, 65 and the backup plate passages 70, they function alternately as first-stage and second-stage impeller passages as the rotor rotates. Additionally, passage 74 in drive shaft 20 directs intermediate pressure fluid to axial passage 62 aligned with slot 65 in the port plate, thereby directing first stage fluid flow to impeller or rotor 22. functions as

FIG. 4 shows the effective discharge pressure 150 of the vane pump relative to the required pressure of the engine as 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). ) The discharge pressure of a centrifugal pump determined by the speed of
54 and the total pump discharge pressure 156, all as a function of pump speed (rpm).

At velocity threshold 158, the sum of the discharge fluid pressures decreases at fluid actuator 102 by spring actuator 8.
6 is sufficient to overcome the force of 6 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.

〔Effect of the invention〕

As described above, the present invention combines the desirable characteristics of vane-type devices and centrifugal-type devices, which have similar properties, to function as a high-pressure positive displacement device at low speeds, and to provide improved reliability and packaging. A rotary hydraulic system is provided that has the size and weight characteristics of a centrifugal system and is particularly useful as a fuel pump for aircraft turbine engines. And as stated above, it is configured to function as a pressure-compensated single-lobe vane pump during engine starting and as a centrifugal pump at normal operating speeds, in accordance with the presently preferred embodiment of the invention. This is also achieved by providing a combination vane and centrifugal pump.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side elevational view of a low-crip hydraulic system in accordance with a presently preferred embodiment of the invention; FIGS. 2 and 3 are taken substantially along lines 22 and 3-3 of FIG. FIG. 4 is a graphical diagram useful in explaining the invention in detail; 10...Fuel pump 12...-Housing 20
- Drive shaft 22 - Rotor 24 - Rear backup plate 28 - Front backup plate 42, 44 - Boat plate 46 - Slot 48 - Vane 50 - Vane lower chamber 52, 53...Slot 60...Rotor passage 6
2...Axial passage 64.65...-Slot 78
・-Orbit ring 84...-Passage 86--Spring actuator 9〇-Through passage 92...Piston
96... Spring seat 98... Coil spring 100.
- Guide pin 102 - Fluid actuator 105... Penetration passage 106 - Sleeve 108
...-Fluid piston 111... Internal stopper 12
6...-Inducer and FIG, 1

Claims (1)

[Scope of Claims] 1. A housing (12), a rotor (22) having a plurality of radially centrifugal slots (46) around the periphery and provided to rotate within the housing, and a rotor (22) having a plurality of radially centrifugal slots (46) arranged to rotate within the housing, and a rotor (22) having a plurality of radially centrifugal slots (46) arranged to rotate within the housing; a plurality of movably provided vanes (48);
radially inwardly directed vane track means disposed within said housing and surrounding said rotor (22) and an annular track ring (78) defining a fluid pressure cavity between said track means and said rotor; A pressure-compensated rotary hydraulic device comprising fluid suction passage and discharge passage means of the housing coupled together, the pressure-compensated rotary hydraulic system being retained by the housing and biasing the raceway ring to an eccentric position with respect to the rotor. spring means (86) and one of said fluid suction passageway and discharge passageway means coupled to said track means to move said raceway ring against the force of said spring means towards a position coaxial with said rotor; Apparatus characterized by fluid actuator means (102) responsive to fluid pressure to control the displacement of the apparatus as a function of the fluid pressure of one of said passage means. 2. said spring means (86) having a first piston (92) disposed radially slidably within said housing and connected to said raceway ring, and a radially oriented axis; 2. The apparatus of claim 1, comprising a spring actuator including a coil spring (98) held in compression between a spring seat located at and said 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 said spring means (86) includes a radial passageway (90) in said housing, said first piston (92) being slidably received within said passageway; 4. The apparatus of claim 3, further comprising means (96) adjustably threaded into said housing radially outwardly of said piston. 5. The apparatus of claim 4, wherein the spring seat further includes a spring guide pin (100) telescopically received in the coil spring (98). 6 the first piston (92) having a base connected to the raceway ring and a cylindrical side wall slidably received in the passageway (90) on the outside and receiving the coil spring therein; 6. The device of claim 5, comprising an open cup-shaped piston. 7. said fluid actuator means (102) comprising a second piston (108) mounted radially slidably in said housing and connected to said raceway ring diametrically opposite said first piston; 3. The apparatus of claim 2, comprising a hydraulic fluid actuator. 8 said fluid actuator (102) further comprises a radial passage (105) in said housing slidably housing said second piston therein; 8. The apparatus of claim 7, including means for forming a seat that limits radial outward movement of the piston. 9 said fluid actuator (102) further comprises means (106) for adjustably positioning said seat within said passageway;
).) The apparatus of claim 8. 10 the fluid actuator (102) comprises a hollow cup-shaped sleeve (102) adjustably threaded into the passageway;
106) and an opening in a side of said sleeve for receiving fluid from one of said passage means, said second piston (
10. The apparatus of claim 9, wherein the sleeve (108) is slidably retained by the sleeve (106) and the seat (111) is integrally formed inside the sleeve. 11 said rotor (22) has a plurality of radially oriented internal passages (60) extending from an open outer end to an inner end around said rotor between each pair of said vanes for directing suction fluid to at least said rotor; Claim 1 comprising passage means (64, 65) within said housing feeding some of the inner ends.
equipment. 12. The apparatus of claim 11, wherein said rotor (22) further includes internal passage means (62) interconnecting all of said inner ends. 13. The apparatus of claim 12, wherein said discharge passage means includes a radially angled passageway (84) extending through said raceway ring. 14 a housing; a rotor configured to rotate within the housing; a plurality of radially extending peripheral slots and a plurality of radially extending peripheral slots extending radially from an outer end to an inner end of the rotor's periphery between the slots; a plurality of vanes individually slidable within the slots; an annular track ring disposed within the housing; and a fluid pressure between the ring and the rotor. a radially inner surface surrounding the rotor to define a cavity and a plurality of radial passages extending through the ring; and a fluid within the housing providing suction fluid to the inner end of the rotor passage. suction means; fluid ejection means radially outwardly of the passageway of the ring and including a discharge cavity of the housing; biasing the vane radially outwardly into sliding engagement with the ring; a combined centrifugal and vane rotary hydraulic system comprising means coupled to the ring for adjustably positioning the ring within the housing in response to fluid pressure of one of the suction means and the discharge means; , a device characterized by means for controlling the displacement of the device as a function of fluid pressure. 15. said spring means being radially slidable within said housing and having a first piston connected to said raceway ring; a spring seat in said housing having a radially oriented axis; 15. The apparatus of claim 14, comprising a spring actuator including a coiled spring held in compression between the first piston. 16. said fluid actuator means comprising a hydraulic fluid actuator including a second piston mounted radially slidably in said housing and connected to said raceway ring diametrically opposite said first piston; 16. The apparatus of claim 15. 17. Claim 17, wherein said housing includes opposed backup plate means including port means in facing engagement with said rotor, said ring being movably disposed between said backup plate means and surrounding said rotor. 14 devices. 18. Claim 18 wherein the means for biasing said vanes comprises a fluid chamber at the radially inner end of each said slot on the underside of the associated vane and means in said port means for supplying fluid to said chamber. 17 devices. 19. The apparatus of claim 18, wherein the passageway in the ring is angled in a radial direction of the rotor. 20. The apparatus of claim 19, wherein the slots and the passageways of the rotor are evenly spaced and alternating with each other in a circumferential direction of the rotor. 21. The apparatus of claim 20, comprising a pump having a shaft connected to the rotor and extending from the housing through one of the backup means and a fluid suction coaxial with the shaft and on the other of the backup means. 22. The apparatus of claim 21, wherein the rotor includes a suction passage that supplies fluid from the suction to the inner end of the radial passage. 23. The apparatus of claim 22, further comprising a helical inducer coupled to the shaft and disposed in the suction to pressurize fluid in the suction.