US2919651A

US2919651A - Power transmission

Info

Publication number: US2919651A
Application number: US463100A
Authority: US
Inventors: Duncan B Gardiner
Original assignee: Vickers Inc
Current assignee: Vickers Inc
Priority date: 1954-10-19
Filing date: 1954-10-19
Publication date: 1960-01-05
Anticipated expiration: 1977-01-05

Description

Jan. 5, 1960 D. B. GARDINER POWER TRANSMISSION Filed Oct. 19, 1954 FIG. 2

INVENTOR. DUNCAN B GARDINER ATTORNEY POWER TRANSMISSION Duncan B. Gardiner, Detroit, Mich., assignor to Vickers Incorporated, Detroit, Mich., a corporation of Michigan Application October 19, 1954, Serial No. 463,1ll

12 Claims. (Cl. 103-136) This invention relates to power transmissions, and is particularly applicable 'to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

The invention is concerned generally with rotary fluid energy translating devices adapted for use in hydraulic power transmission systems and in particular to those of the sliding vane type.

A form of pump in the hydraulic power transmission field utilizes a rotor having a plurality of spaced radial vanes rotatable therewith and slidable relative thereto in slots provided in the rotor. The rotor and vanes cooperate with a vane track in the'stator member which defines one or more working chambers between the outer periphery of the rotor and the vane track and through which the vanes pass carrying fluid from the inlet port to the outlet port.

The outer edges of the vanes are adapted to be kept in contact with the track and the spacing between adjacent vanes varies as the rotor turns producing a pumping action. As the rotor turns the vanes are extended outwardly by centrifugal force and are retracted inwardly by cam contour action of the track during thepressure i A or discharge phase of the device. .On the discharge phase wear take up. A large amount of wear on the ends of the vanes and to some extent on the cam trackcan take place with only a' very slight effect on the efficiency of the pump. This is due to the fact that the-vanes are maintained in contact with'the cam track by centrifugal force and fluid pressure and that the pump action is independent of how much the tips of the vanes have been worn oft". Although'a certain amount of wear is ennissible without destroying the efliciency of the pump, when certain limiting speeds and pressures and volumetric capacities are exceeded the wear rate is so great as to be economically unfeasible. Thus one limiting factor in this design of pump has been foundto be the rate'of:

wear between the outer edges of the vanes and the surface of the vane track under excessive operating conditions.

Because of the limitations of devices wherein outlet pressure is continuously conducted to the inner ends of the vanes, other constructions have been designed which connect the high pressure side of the device to theinner ends of the vanes only on the high pressure or discharge phase thereof and which connect the low pressure or inlet side of the device tothe inner ends of the vanes on the suction phase. Although it would appear that this would providepproper balancingof'theinward and 2,919,651 Fatented Jan. 5, 1960 "ice 2 outward pressures on the vanes' as they passed through the low and high pressure working chambers of the device, this is not the case. At higher speeds'the vanes become improperly balanced and not only is the volumetric efliciency of the device decreased but likewise its pumping capacity. As the speed of the device increases the centrifugal force urging the vanes against the track type.

It is another object of thisinvention to provide a fluid energy translating device having an improved vane biasincreases but this advantage is overcome by an'increased pressure diiferential tending to separate the vanes from the track. As the speed of the rotor increases the pressure difierential required to cause the vanes to pump the fluid out of the intervane spacesinto the delivery passage also increases and at certain higher speeds becomes so great that the vanes are unbalanced inwardly and move away from the track. I

Still other types of devices have been designed to provide a proper unbalanced condition "to meet the requirements which utilize intricate valving and portingand even auxiliary booster units.

It is therefore a general object of this invention to provide an improved low cost, eflicient and long wearing fluid energy translating device, of the sliding vane ing arrangement.

It is still-another object ,of this invention to provide a fluid energy translating device having' an improved vane structure and vane biasing arrangement which reduces wear and increases eflicien cy.

It is a further object of this invention to provide a rotary fluid energy translating device incorporating sliding stepped vanes and a pressure transmitting arrange ment to both ends and the stepped portion of the vanes which assures proper control of the vanes during the com plete cycle at high pressure and high speeds and which reduces wear'and increases volumetric efliciency. I

It is also an object of'this invention to provide a fluid energy translating device incorporating radially sliding stepped vanes with a pressure transmitting system associated therewith to produce a controlled, safe and efiicient pressure differential thereon for urging the vanes in contact with the vane track.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred form of the present invention is clearly shown.

A In the drawing:

Figure 2 is a sectional view taken on line 2 2 of Figure 1.

Figure 3 is a sectional view taken on line 33"of Figure 1.

Figure 4 is an enlarged partial sectional view of the values as illustrated in Figure 2.

Referring now to Figure 1 there is shown a rotary fluid pump indicated generally by the numeral 10, the

housing of which comprises a cam ring" section 12 sandwiched between a body section 14 having a wear plate 16 and an end cover 13, all of which are suitably conneced to each other by bolts 20. The body section 14 is provided with an inlet supply connection port 22 having an inlet passage 24 leading therefrom which is branched and terminates in a pair of fluid openings, one' of which is sho'wn in Figure 1, registering with duplicate

opposed fluid openings

26 and 27 extending through the cover 18 which leads directly from a pressure delivery chamber 38 formed in an enlarged bore 32 of the end cover 18 when a pressure plate 34 is floatably mounted in the bo're 32. The pressure plate 3 2- and wear plate 16 are each formed with a fiat surface indicated, respectively, by the numerals 36 and 38 which abut opposing flat faces 40 and 4-2 of the cam ring 12 and provide fluid sealing engagement for the immediately adjacent faces of a rotor 44 mounted within the cam ring 12. The pressure plate is adapted to be urged against a portion of the flat face 40 of the cam ring 12 and in fluid sealing engagement with the rotor by pressure in the pressure chamber. A spring 35 initially biases the pressure plate toward the rotor until pressure builds up in the pressure chamber.

The rotor 44 is driven by a shaft 46 provided with a seal 47, and extends from the body for connection to a prime mover, not shown. The shaft is spline connected to the rotor at 48 and is rotatably mounted in

bearings

58 and 52, mounted in the body 14. ring seals 54 and S6 prevent leakage at the juncture of the end cover 18 and the wear plate 16 with the cam ring 12 while an O ring seal 58 prevents leakage at the juncture of the body 14 and the wear plate 16.

The innersurface of the cam ring 12 forms a cam track substantially elliptical in shape, indicated by the numeral 60, against which the outer tips 62 of vanes 64, the latter of which are slidably mounted in slots 66 of the rotor 44, are adapted to be maintained in contact. The cam track contour and the outer periphery of the rotor define two opposed working chambers, indicated by the

numerals

68 and 70, which for the purposes of convenience, may be divided. into fluid inlet zones or fluid. delivery zones. The fluid inlet zo'nes are those portionsv of the

working chambers

68 and 70 registering with the opposed fluid inlet.

openings

26 and 27 in the Wear plate 16. The fluid. delivery zones are those p.0r-

tions of the

working chambers

68 and 70 registering respectively with opposed arcuate

fluid delivery ports

72 and 74 in the pressure plate 34, which are connected to the pressure chamber 30 by means of duplicate passages 75 leading therefrom, one of which is shown in Figure 1.

The vane. track 60 includes an inlet zone ramp extending from a to b, a true arc portion extending from b to c, a delivery zone ramp extending from c to d, and another true are portion extending from d to e. The track is symmetrical about both its major and minor axes, thus each of the ramp and. true are portions from a to e are duplicated in. the lower portion of the track. As the ends of the vanes traverse the inlet ramps, the vanes mo've radially outward with respect to the rotor, and while the vane ends traverse the delivery ramps the vanes move radially inward. In the true are portions, the vanes partake of no radial movement.

The inner ends of the vane slots 66 are enlarged to form, with the inner ends 77 of the vanes 64, small enclosed undervane pressure chambers 78 which undergo cyclic contraction and expansion during rotation of the rotor. Each vane slot 66 is also formed with a stepped portion indicated by the numeral 80 which, together with a step in each vane indicated by the numeral 82, forms.

an enclosed intermediate pressure chamber 84 which remains enclosed while undergoing cyclic expansion and contraction as, the rotor revolves.

In the form of device illustrated a flow path is formed connecting the high pressure side of the device to the intermediate chambers and which also interconnects the contracting and expanding intermediate chambers. The flow path is formed byproviding diametrically opposed po'rts 86 and diametrically opposed ports 88 in the pressure plate, the former of which are adjacent the inlet ramps and connected to the pressure chamber 30 by drilled passages 90, while the latter ports 88 are adjacent the outlet ramps. and. connected to the passages 75 which lead to the pressure chamber 39 by angular restriction passages indicated by the numeral 92. The pressure chamber 30 thus forms with the pressure plate outlet or

delivery ports

72 and 74 and the passages 75 a continuous outlet passage leading to the outlet port 28 and also forms with the diametrically opposed ports 86 and 88 a continuous flow path for connecting the high pressure side of the device to the intermediate chambers and interconnecting the expanding and contracting intermediate chambers to each other. The vanes traversing the outlet ramp cd and its duplicate outlet ramp are retracted. causing contraction of their associated intermediate chambers while simultaneously the vanes traversing the inlet ramp a-b and its duplicate inlet ramp are extended causing an expansion of their associated intermediate chambers. The retracting vanes continuously push fluid out of their associated intermediate chambers into the flow path simultaneously feeding the expanding intermediate chambers of the vanes traversing the inlet ramps.

For the purpose of equalizing the pressure on the inner and outer ends of the vanes, the rotor is providedwith a plurality of angular drilled passages 94", one for each vane slot, which leads from the periphery offthe rotor, between the vanes to the enlarged chambers 78' at the inner end of each vane slot. The outer end of'thejvanes are constructed with a trailing taper 96 and a relatively smaller leading taper 98 to form the tips 62 of the vanes which contact the vane track. The outer surfaces of the vanes comprising the tapers 96 and 98 are exposed to the pressures in the expanding and contracting intervane spaces, and by means of the angular passages 94, the cyclically changing intervene pressure is conducted to the inner. chambers 78..

The restricted. passages 92, which connect the intermediate vane chambers to the pressure chamber passages 75 are adapted. to. create a pressure in the intermediate stepped. vane chambers on the discharge phase of the device greater than the. pressure in the end chambers of the. vanes for producing a favorable unbalanced outward force thereon. The size of the restrictions and the effective area of the exposed surface of the stepped portions of the vanes are preselected to create a resultant force sufficient to maintain thetips of the vanes in contact with the vane track but low enough to prevent excessive ring wear. In the type of vane structure illustrated, the length of the smaller tapered portion of the outer ends of the vanes, and the effective area of the stepped 'portion of the vane, are also correlated and preselected to provide at least a 2:1 ratio in favor of the stepped portion. of the vane. As the tip of the vane is about to enter the discharge portion of the ramp from the true are portion, only the smaller tapered portion of the vane is exposed to high pressure and the selected area ratio is adapted to insure contact of the vane tips against the vane track during this portion of the cycle.

The

fluid inlet ports

26 and 27, which extend completely through the wear plate 16, are also duplicated respectively by

ports

100 and 102 in the face 36 of the pressure plate to produce proper filling and balance on opposite sides of the. rotor. In order to facilitate filling of the undervane chambers during the suction stroke and during high. speed operation,v the Wear plate is also provided, with auxiliaryv inlet ports 1.04 and 106 which are connected to the inlet passages of the body device by slots 1.081 and 114) in the wear plate. Duplicate auxiliary inlet ports 112 and 114 are provided in the face of the pressure plate adjacent the rotor, which lead respectively by slots 11-6 and 118 to a recess 120 in the plate in alignment with the rotor shaft. Inlet fluid is conducted from the. auxiliary inlet porting in the wear plate side of the device through the medium of the spacing between the shaft and rotor. splining to the recess and by means. of. the

slots

116 and 118 in the pressure plate to the. duplicate: auxiliary inlet ports 112 and. 114 of the pressure plate. Dowel pins 122 are utilized to provide proper alignment of the porting located in the wear and pressure plates with the working chambers of the device;

In operation, as the rotor turns, fluid entering the inlet port is conducted by the branched inlet passage 24 and the openings thereof to the

arcuate inlet ports

26 and 27 of the wear plate to the fluid inlet zones of the working

chambers

68 and 70. Fluid is also conducted to the expanding undervane chambers 78 from the fluid inlet zones by means of the angular rotor passages 94. Proper filling of the undervane chambers is insured by the

auxiliary inlet ports

104 and 106 which are connected to the branched inlet passage 24 through the

slots

108 and 110 in the wear plate. Proper filling and rotor balancing is also facilitated by the

duplicate inlet ports

100 and 102 of the pressure plate registering with the working

chambers

68 and 70 on the opposite side of the rotor and by the duplicate auxiliary undervane porting 112 and 114, also in the pressure plate, which is connected to the splined rotor and shaft passageway by the

slots

116 and 118 in the pressure plate.

The displacement of the device is conducted from the fluid delivery zone of the working chambers of the device through the

delivery ports

72 and 74 of the pressure plate to the pressure chamber 30 and thence by means of outlet connection port 28 to a hydraulic system, not shown. As the vanes pass through the inlet and the outlet ramps of the vane track, the pressure at the extreme ends of the vanes is equalized. The resultant force on the ends of the vanes, however, is unbalanced because of the differential end areas of the vanes. As the vanes pass through the inlet zones across the inlet ramp at to b and the duplicate inlet ramp, they are extended outwardly by centrifugal force, but engagement of the tips of the vanes with the vane track is insured by a small force created on the stepped portions of the vanes. This is accomplished'by transmitting pressure from the pressure chamber 30 through the drilled passages 90 and the intermediate chamber pressure ports 86 of the pressure plate to the intermediate vane chambers 84. The magnitude of the force, resulting from the transmittal of pressure to the preselected effective surface area of the stepped portions 82 of the vanes, is intended to be sufficient for insuring contact of the tips 62 of the vanes 64 with the vane track 60, but of a proper value for minimizing the wear rate of the vane tips and vane track. In most cases, only a slight force is necessary.

The pressure at the unbalanced end areas of the vanes which are passing through the delivery ramp is substantially equalized and if the same pressure were transmitted to the remaining balancing area of the stepped portion of the vanes, it would appear that because of the balanced area conditions, centrifugal force alone would be suflicient to maintain the tips of the vanes in contact with the vane track. As previously explained, however, the pressures existent at the ends of the vanes as they pass across the delivery ramp are not completely equalized, and the pressure differential is in favor of urging the vanes from the track. This unfavorable condition is overcome by increasing the pressure in the contracting intermediate vane chambers to a magnitude in excess of outlet pressure transmitted to the ends of the vanes. The pressure in the intermediate vane chambers is increased by means of the restricted passages 92. Both the vane end chambers 78 and the intermediate chambers 84 contract in size as the vanes pass across the delivery ramp cd, and the duplicate delivery ramp. The fluid displaced from the intermediate chambers must pass through the restricted passages 92 to the outlet passages 75 in the pressure plate and thence to the pressure chamber 30 which also serves to interconnect the contracting intermediate chambers with the expanding intermediate chambers. The size of the restrictions is thus preselected to, raise the pressure sufliciently in the inter- 6 mediate vane chambers, when acting on a predetermined efiective area of the stepped portions of the vanes, for overcoming the slight pressure differential conditions existing on the outer ends of the vanes. The pressure is adapted to be raised sufficiently to overcome the slight unbalanced conditions existing on the ends of the vanes in favor of separating the vanes from the vane track to a favorable unbalanced condition insuring contact of the tips of the vanes with the vane track, but low enough to provide a favorable wear rate condition. The pressure value for the intermediate vane chambers may be selected for most efiicient operation for any particular unit.

Devices embodying the invention operate at much higher pressures and speeds than conventional devices of the type previously described. The greatly improved performance of the device is due to the stepped vane design with end and intermediate pressure chambers and the controlling of the pressure within one of the chambers, which is the intermediate chamber in the form of device illustrated. An unbalanced force is created by the design which tends to maintain the tips of the vanes in contact with the track during the complete cycle of the device and yet minimizes excessive wear rate while providing utmost efliciency and long life.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a fluid pressure energy translating 'device of the sliding vane type comprising a body including a track member and wherein one end of each vane abuts the track and the intervane spaces during a cycle of the device undergo alternate expansion and contraction phases, said body including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of said passages being a low pressure passage and the other of said passages being a high pressure passage, means forming two pressure chambers for each vane, each vane having two surfaces, one in each chamber, both being effective under pressure in said chambers to urge the vanes into engagement with the track, means for conducting the cyclically changing intervane pressure to only one of said two chambers, passage means connecting the high pressure. passage to the other of said chambers during theintervane spaces expansion phase, and means forming a restricted flow path from the said other of said chambers during the intervane spaces contraction phase for creating a pressure in said other chamber during said phase greater than is existent in the high pressure passage.

2. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps, and wherein the ends of the vanes abut the track and the intervane spaces undergo alternate expansion and contraction as the vanes traverse the inlet and outlet ramps, said stator including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of which is a high pressure passage and the other of which is a low pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming two pressure chambers associated with each vane,

each vane having surfaces, one in each chamber, ef-

and means forming a restricted flow path from the other.-

of said two chambers as the vanes traverse the outlet "ramp for creating a pressure in the said other chamber greater than in the high pressure passage.

3. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps, and wherein the ends of the vanes abut the track and the intervane spaces undergo alternate expansion and contraction as the vanes traverse the iniet and outlet ramps, said stator including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of which is a high pressure passage and the other of which is a low pressure passage, the combination of a plurality of stepped vanes slidabiy mounted in a plurality of stepped slots in the rotor and forming two pressure chambers associated with each vane, each vane having surfaces, one in each chamber, effective under pressure to urge the vanes into engagement with the track, porting means for conducting the cyclically changing intervane pressure to only one of said two chambers, passage means connecting the high pressure passage to the other of said two chambers as the vanes.

traverse the inlet ramp, and means forming a restricted flow path from the other of said two chambers as the vanes traverse the outlet ramp and creating a pressure in the said other chamber greater than in the high pressure passage.

4. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps, and wherein the ends of the vanes abut the track and the intervane spaces undergo alternate expansion and contraction as the vanes traverse the inlet and outlet ramps, said stator including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of which is a high pressure passage and the other of which is a low pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming two enclosed pressure chambers associated with each Vane, each vane having surfaces, one in each chamber, effective under pressure to urge the vanes into engagement with the track, porting means for conducting the cyclically changing intervane pressure to only one of said two chambers, and passage means connecting the high pressure passage to the other of said two chambers as the vanes traverse the inlet ramp and the outlet ramp.

5. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps which the outer ends of the vanes engage and causing during a cycle of the device alternate expansion and contraction phases of the intervane spaces, said stator having inlet and outlet passages for conducting fluid to and from the intervane spaces, one of which is a low pressure passage and the other a high pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming an end chamber and an intermediate chamber in each slot in which an end surface and an intermediate surface of each vane are respectively effective under pressure in said chambers to urge the outer ends of the vanes in engagement with the track, means for porting the cyclically changing intervane pressure to the inner chambers in timed relation with the expansion and contraction phases of the intervane spaces, and means forming a continuous flow path interconnecting the intermediate chambers of the vanes, traversing the inlet and outlet ramps and the high pressure passage.

6. In a fluid pressure energy translating device of the sliding vane type comprising a body including a track having an inlet and an outlet ramp separated by a substantially true are section and wherein the intervane spaces during a cycle of the device undergo expansion and contraction phases between the true are portion of the track, said body having inlet and outlet passages for conducting fluid to and from intervane spaces one of which is a low pressure passage and the other of which is high pressure passage, means forming an end chamber and an intermediate chamber for each vane, each vane having an end surface and an intermediate surface respectively in said chambers and effective under pressure therein to urge the outer ends of the vanes in engagement with the track, each vane having a leading and a trailing surface on opposite sides of the track engaging outer end of the vane, which are exposed to pressures in the intervane spaces as the vanes traverse the track ramps, the effective area of the vane intermediate surface being at least twice that of the effective area of the leading surface the pressure on which tends to separate the vane from the track, means for conducting the cyclically changing intervane pressure to one of said two chambers, and passage means interconnecting the high pressure passage and each of the other of said two cham bers to each other during the expansion and contraction phases of the intervane spaces.

7. In a fluid energy translating device of the slidingvane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps, and wherein the ends of the vanes abut the track and the intervane spaces undergo alternate expansion and contraction as the vanes traverse the inlet and outlet ramps, said stator including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of which is a high pressure passage and the other of which is a low pressure passage, the combination of a plurality of stepped vanes slida'oly mounted in a plurality of stepped slots in the rotor and forming two enclosed pressure chambers associated with each vane which remain enclosed as the intervane spaces expand and contract, each vane having surfaces, one in each chamber, effective under pressure to urge the vanes into engagement with the track, porting means for conducting the cyclically changing intervane pressure to only one of said two chambers, and means forming a continuous flow path interconnecting the high pressure passage and each of the other said chambers to each other, as the vanes traverse the inlet and the outlet ramps.

8. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps which the outer ends of the vanes engage and causing alternate expansion and contraction phasesof the intervane spaces, said stator having inlet and outlet passages for conducting fluid to and from the intervane spaces, one of which is a low pressure passage and the other a high pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming an end chamber and an intermediate chamber in each slot in which an end surface and an intermediate surface of each vane are respectively effective under pressure in said chambersto urge the outer ends of the vanes in engagement with the track, means for porting the cyclically changing intervane pressure to the end chambers in timed relation with the expansion and contraction phases of the intervane spaces, and means connecting the high pressure passage to the intermediate chambers during the intervaneexpansion and contraction phases of the device.

9. In a fluid pressure energy translating device of the sliding vane type comprising a body including a track member and wherein one end of each vane abuts the track and the intervane spaces during a cycle of the device undergo alternate expansion and contraction phases, said body including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of said passages being a low pressure passage and the other of said passages being a high pressure passage, means forming two pressure chambers for each vane, each vane having two surfaces, one in each chamber, both being eifective under pressure in said chambers to" urge the" vanes into engagement with the track, means for connecting in timed relation the cyclically expanding and contracting intervane spaces to one of said two chambers, passage means connecting the high pressure passage to the other of said chambers during the intervane spaces expansion phase, and means forming a restricted fiow path from one of the said two chambers during the intervane spaces contraction phase for creating a pressure in the said one of said two chambers during said phase greater than is existent in the high pressure passage.

10. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps, and wherein the ends of the vanes abut the track and the intervane spaces undergo alternate expansion and contraction as the vanes traverse the inlet and outlet ramps, said stator including an inlet and an outlet passage for conducting fluid to and from the intervane spaces, one of which is a high pressure passage and the other of which is a low pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming two enclosed pressure chambers associated with each vane which remain enclosed as the intervane spaces expand and contract, each vane having surfaces, one in each chamber, etfective under pressure to urge the vanes into engagement with the track, porting means for connecting the cyclically expanding and contracting intervane spaces to only one of said two chambers, means connecting the other of said two chambers to the high pressure passage as the vanes traverse the inlet ramp, and means forming a restricted flow path from one of said two chambers as the vanes traverse the outlet ramp for creating in said chamber, as the vanes traverse said ramp, a controlled pressure greater than is existent in the high pressure passage.

11. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps which the outer ends of the vanes engage and causing alternate expansion and contraction phases of the intervane spaces, said stator having inlet and outlet passages for conducting fluid to and from the intervane spaces, one of which is a low pressure passage and the other a high pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming an end chamber and an intermediate chamber in each slot in which an end surface and an intermediate surface of each vane are respectively effective under pressure in said chambers to urge the outer ends of the vanes in engagement with the track, means for connecting the cyclically changing intervane spaces to the end chambers in timed relation with the expansion and contraction phases of the intervane spaces, passage means connecting the high pressure passage to the intermediate chambers during the intervane spaces contraction phase, and means forming a restricted flow path from one of said chambers during the intervane spaces contraction phase for creating a controlled pressure in the said one of said two chambers during said phase greater than is existent in the high pressure passage.

12. In a fluid energy translating device of the sliding vane type comprising a stator having a rotor rotatably mounted therein and defining a vane track with inlet and outlet ramps which the outer ends of the vanes engage and causing alternate expansion and contraction phases of the intervane spaces, said stator having inlet and outlet passages for conducting fluid to and from the intervane spaces, one of which is a low pressure passage and the other a high pressure passage, the combination of a plurality of stepped vanes slidably mounted in a plurality of stepped slots in the rotor and forming an end chamber and an intermediate chamber in each slot in which an end surface and an intermediate surface of each vane are respectively efiective under pressure in said chambers to urge the outer ends of the vanes in engagement with the track, means for connecting the intervane spaces to the end chambers in timed relation with the expansion and contraction phases of the intervane spaces, passage means connecting the high pressure passage to the intermediate chambers during the intervane spaces expansion and contraction phase, and means forming a restricted flow path from the intermediate chambers during the intervane spaces contraction phase for creating a pressure in the said chambers during said phase greater than is existent in the high pressure passage.

References Cited in the file of this patent UNITED STATES PATENTS 559,324 Dyer Apr. 28, 1896 586,694 Renz July 20, 1897 1,087,181 Pitman Feb. 17, 1914 1,093,005 Myers Apr. 14, 1914 1,805,063 Wrona May 12, 1931 1,989,900 Vickers Feb. 5, 1935 2,473,309 Stephens June 14, 1949 2,499,763 Livermore Mar. 7, 1950 2,545,238 MacMillin et al. Mar. 13, 1951 2,612,115 Ernst Sept. 30, 1952 2,714,858 Barkeij Aug. 9, 1955 2,739,539 Gardiner Mar. 27, 1956 2,743,090 Malan Apr. 24, 1956 FOREIGN PATENTS 433,488 Great Britain Aug. 15, 1935