US3194122A - Hydraulic cam motor vane switching system - Google Patents

Description

July 13, 1965 w. R. KEE 3,194,122

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July 13, 1965 W. R. KEE 3,194,122

HYDRAULIC CAM MOTOR VANE swITcHINc SYSTEM Original Filed Dec. 14, 1962 5 Sheets-Sheet 3 United States Patent 1 claim. (ci. @1 104) This application is a division of co-pending U.S. application Serial No. 244,846 tiled December 14, 1962.

The present invention relates to means for maintaining vanes in vane-type hydraulic power converters in contact with the cam rotor. More particularly, the present invention relates to means for applying and maintaining pressure on the top surface of the vanes in a vane-type hydraulic power converter when the power converter is in operation, and for switching the applied pressure when the rotor is reversed in its direction of rotation so that the vane will be maintained in contact with the rotor at all times.

In vane-type fluid power converters of a character preferably utilizing hydraulic fluid such as those of the type disclosedby J. R. Farron et al. in Patent No. 2,845,872, it is often desirable to design the power converter to reverse the direction of rotation of the output shaft connected thereto by reversing the direction of flow of hydraulic fluid from the supply source to the pressure ports conducting pressurized iluid to the rotor. The process by which these converters are reversed is called switching This reversal requires not only a change in pressure sources to drive the cam lobes on the rotor in the opposite direction, but it is also desirable to constantly apply pressure to the top surface of the vanes to keep them rmly in contact with the rotor, thereby minimizing leakage and promoting faster build-up of pressure for optimum response, stiffness, and torque output.

Therefore, it is an object of the present invention to provide means for maintaining pressure on the top surface of the vanes in vane-type hydraulic power converters to thereby maintain the vanes in contact with the rotor.

It is a further object of the present invention to provide means for maintaining the vanes of vane-type uid power converters in contact with the converter rotor by application of pressure to the top surface of the vanes and for switching the application of pressurized fiuid when the power converter is reversed in its direction of output rotation.

It is another object of the present invention to provide a iiuid pressureresponsive means for maintaining the vanes of vane-type hydraulic power converters in contact with the converter rotor by applying a part of the converter operating pressurized tluid to the top surface of the vane, and for switching the application of pressurized fluid when the operating pressure of the fluid in the converter is reversed in order to reverse the direction of operation of the power converter. i

Other objects, advantages and-novel features of the instant invention will become apparent from the following detailed description of the invention when considered in conjunction with the` accompanying drawings wherein:

FIG. la is a diagrammatic view in section of one embodiment of the present invention taken through a typical power converter showing in diagrammatic form the relationship of the various parts of the invention;

FIG. lb is a view similar to FIG. la of a second embodiment of the present invention;

FIG. 2a is a diagrammatic View in vertical section taken along the line Ztl-2a of FIG. la;

FIG. 2b is a diagrammatic View of a fragmentary portion of the embodiment of the present invention of FIG. 1b taken along the line 2b-2b of FIG. 1b and showing in a manner similar to that of FIG. la, a sectioned illustration of a typical vane-type hydraulic power converter;

FIG. 3 is an enlarged broken view of the vane and vane chamber arrangement of FIG. 2b; and

FIG. 4 is an enlarged sectional View taken along line 4 4 of FIG. 3 showing the relative position of the vane, vane chamber, and pressure passages.

Referring now to the drawings in which like reference numerals refer to like parts; there is shown in FIGS. la and 2a, a sectional view of a typical vane-type hydraulic power converter, having a case 1, a rotor 2, pressure passages 3 and 4, and vane assembly 5. The vane sealing system as embodied in the present invention comprises at least two embodiments as shown generally in FIGS.` la and IIJ, and FIGS. 2a and 2b. FIGS. la and 2a `show a vane sealing system generally designated as an O ring switching system. FIGS. 1b and 2b disclose a vane sealing system designated as a vane switching system.

Referring nowto FIGS. la and 2a, vane system 5 comprises an O ring 6, outer O ring groove 7, inner O ring groove 8, pressure passage 9, vane chamber 11, vane 12, and pressure release grooves 13. An annular passage 16 between case 1 andhousing 14, as shown in. FIGS. la and 2n provides a pressure passage between pressure passage 3 and O ring 6 on one side and pressure passage 4 and O ring 6 on the other side. These two passages are sealed relative to each other by action of O ring 6. As shown, the vane hydraulic power converter is operating with the rotor having a clockwise rotation. In this mode of operation7 pressure passages 4 act to conduct fluid P1 under high pressure from a source of hydraulic fluid, generally indicated as a pump at P toward the rotor lobes beneath the passage, while pressure passages 3 exhaust fluid at a lower pressure as the exhaust chamber undergoes a decrease in its volumetric capacity as the leading side of the rotating rotor lobe moves toward the vane. As can be seen by reference to FIG. 2a, as the rotor rotates, the chamber defined by the high pressure side of vane 12, between the case 1 and rotor 2, undergoes a volumetric increase as the trailing side of the cam lobes 15 move away from vane 12 under the inuence of the highly pressurized fluid in pressure passages 4. The chambers beneather the exhaust pressure passages 3 are compressed as cam lobes 15 move toward vane 12 to that any entrapped iluid P2 within the chamber is displaced and exhausted from pressure passages 3. It is apparent that in the absence of the incorporation of the structural embodiment of the present invention directed to the structure generally indicated `at 5, the combination of the increasing pressure due to the compression of fluid in the chambers between the pressure passages 3 and the high pressure entering through pressure passages 4 would tend to exert an upward force on vane 12 and thereby lift the vane from contact with the rotor, short-circuiting high pressure uid from high pressure passages 4 to low pressure passages 3 beneath the vane.

In `the embodiment of the present invention, shown in FIGS. la and 2a,"the high pressure fluid P1 entering pressure passages 4 is 'also conducted through annular passage 16 to O ring 6 to thereby disengage O ring 6 from its sealing relationship with respect to pressure passage 9. It is to be noted that inner O ring groove 8 has been reduced in size by insertion of portedmetal member 1%. This modification is only necessary when exist-` ing `vane-type hydraulic power converters are modified to include the present invention. If an `entire vane-type hydraulic power converter were to be designed to initially incorporate the inventive concept of the present invention, it will be apparent that inner O ring groove 8 would be designed so that the ported metal member 13 would not be necessary. Upon disengagement of O ring 6 from the entrance of pressure passage 9, a part of the high pressure fluid from pressure passage iis conducted down pressure passage 9 into-vane chamber 11. The high pressure fluid P1 in vane chamber 11 acts on the top surface of vane 12 to exert a downward force on vane 12 to thereby maintain it in contact with rotor 2. The sealed contact between vane 12 and rotor 2 maintains a pressure differential with respect to the exhaust side of the lobe between the chambers located in the space between the casing 1 and the rotor 2.

In operation, the rotor rotates in a clockwise direction under the influence of high pressure fluid P1 entering the chambers beneath pressure passages 4. As the rotor rotates in a clockwise direction, the chambers located beneath pressure passages 4 undergo a volumetric increase due to the movement of rotor cam lobes 1S away from vane 12, and the chambers beneath exhaust passages 3 undergo a volumetric decrease due to movement of cam lobe 1S toward vane 12. It is to be noted that, in the absence of the present invention, the structural embodiment of the combination of the increasing pressure on one side of vane 12 due to the compression of the fluid within the compressed chambers and the high pressure uid P1 entering the expanding chambers beneath pressure passages 4 on the other side of vane 12 would tend to raise the vane 12 from engagement with the rotor 2. However, the high pressure fluid P1 on the top surface of vane 12, due to the operation of the present invention, maintains vane 12 in contact with rotor 2. The vane-type hydraulic power converter is reversed in direction by switching valve V in a manner whereby the application of the high pressure uid P1 from pressure passage 4 to pressure passages 3 together with a converse porting of the exhausting fluids P2 to the low pressure return or dra-in line 4 is accomplished. Annular passage 17 conducts ya part of the high pressure fluid P1 now flowing in lines indicated at P2 into pressure passages 3, thence to O ring 6, thereby to switch O ring 6 across outer O ring groove 7 for conduction of high pressure uid P1 from annular passage 17 into chamber 9 and conversely fluid P2 is now flowing in lines indicated as P1. Due to the switching action on O ring 6, pressure is maintained on the top surface of vane 12 even during reversing action of the motor. The embodiment of the present invention, as shown in FIGS. la and 2a, provides for switching by valve V of the .applied pressure from the normally high pressure passage 16 to the normally low pressure passage 17 at the same moment the high pressure fluid is switched from the normally high pressure passages 4 to the normally low pressure passages 3 to reverse the direction of rotation of the rotor to thereby maintain sufficient pressure on the top surface of vane 12 to bias it downward into engagement with rotor 2. In this embodiment, highpressure fluid from one or the other of the two pressure ports is gated to the vane chamber 11 by yinduced lateral movement of O ring 6 in its outer groove 7 in response to pressure diiferentials between pressure passages 3 and d. Minimal clearance between vane 12 and vane chamber 11 keeps vane 12 in a vertical position while permitting up and down movement of the vane as it follows the contours of the rotor cam.

A second embodiment of the present invention is shown in FIGS. 1b and 2b through 4. In this embodiment of the present invention, vane 12 itself serves as the switching mechanism to port Veither pressure passages 4 or pressure passages 3 t-o the vane chambers 11 above vanes 12 depending upon the direction of rotation of the rotor. As compared to the O ring method, somewhat greater clearance of the vanes in their Islots is essential (0.001 in. versus 0.0002 in). This increased clearance provides vane pressurization by allowing high-pressure ui-d to reach the vane chamber along the sides of the vanes. It isdeemed apparent by reference to FIG. 1b, that the requirement for O ring switching may be eliminated by insertion of metal seal 1@ into inner O ring groove 8. As mentioned in the description of the embodiment of the invention shown in F1GS. 1a and 2a, this seal is not necessary if the entire vane-type hydraulic power converter is so designed as to initially include structural details configured to incorporate the inventive concept of the present invention. Obviously, in such a case, metal seal 19 and pressure passage 9 are not necessary in the present embodiment of the invention as shown in FIGS. lb and 2b. However, vane-type hydraulic power converters may be designed to use alternatively either embodiment of the present invention by use of the metal seal 19, or the combination .of the two embodiments may be incorporated into the same converter. As is readily apparent by reference to FlGS. 2b and 3, the direction of rotation of the vane-type hydraulic power converter is clockwise which indicates that high pressure tluid enters pressure passages #i to act on cam rotor 2. Under the influence of the high pressure uid in pressure passages 4, vanes 12 are shifted at their point of contact with respect to cam rotor 4 in a direction toward the low pressure chamber beneath pressure passages 3. As a result of the shifting of the points of contact .of vanes 12 with respect to rotor 2, the side of the vanes closest to exhaust pressure passages 3 seal vane chambers 11 from passage of fluid into the chamber beneath pressure passages 3. On the other hand, the side of vanes 12 closest to pressure passages 4 is moved away from the vane chamber walls so that high pressure fluid passes from the chambers beneath pressure passages 4 along the side of vanes 12 into the portion of vane chambers 11 above vanes 12. Grooves 21 and 22 are provided in the walls of vane chambers 11 to provide for lubrication of vanes 12 as well .as to provide for equal pressure on the sides of vanes 12 within vane chambers 11. fluid will leak through grooves 21 into the low pressure chambers below pressure passages 3, but this leakage is not considered sutciently signicant to adversely affect in any way the operation of the apparatus embodying the present invention. When it is desired to reverse the direction of the rotation of rotor 2, the high pressure iluid entering pressure passages 4 is switched by Valve V to pressure passages 3. Since the construction of the reversing valve is of a conventional nature Well-known in the art, the details of the structure thereof are not herein described as they form no part of the instant invention. The diagrammatic representation thereof is presented merely for purposes of illustration and to facilitate a better understanding of the instant invention. Upon this switching, the rotor 2 reverses its direction of rotation and pressure passages 3 become the high pressure passages while pressure passages 4 become the exhaust or drain passages. At the moment high pressure uid enters pressure passages 3, the portions of vanes 12 in contact with rotor 2 are shifted toward pressure passages 4 so that they engage the vane chamber walls closest pressure passages 4 in a sealing relationship while the portions of the vanes closest pressure passages 3 are moved away from the vane chamber walls to conduct high pressure fluid to the top of vane chambers 11 to thereby induce movement of the vanes in a downward direction into engagement with rotor 2. This embodiment of the present invention provides a rapid response switching means for switching the application of Huid under high pressure from an external flow reversing valve V in a manner to induce movement of vanes 12 into engagement with rotor 2 and from one group of pressure passages to the other when the direction of rotation of the rotor 2 is desired to be reversed.

To achieve positive pressurization of all vanes, each vane must remain in contact with the rotor cam 2 under all operating conditions. 1f the vane lifts, high pressure fluid is short-circuited to low pressure fluid causing loss of motor torque and stiffness in proportion to such leak-V It is to be noted that some of the high pressurel age. Pressure relief `grooves 13 are incorporated in the vane-type iiuid power converter to facilitate the escape of uid preferably of a hydraulic type Which might become trapped against the vane and be thereby trapped upon the approach of a lobe 15 of cam rotor 2 when the motor is desired to be reversed in direction. If fluid does become trapped against the vane, instantaneous lift will occur when the converter is reversed in its direction of rotation. Therefore, the pressure relief grooves 13 are incorporated in a manner as illustrated, for the purpose of prevention of vane lift.

It is thus apparent that the present invention incorporates instrumentalities for maintaining the vanes of the vane-type hydraulic power converters continuously in a sealing engagement with the rotor thereby to obviate any tendency toward short-circuiting of high pressure fluid from the high pressure passages to the low pressure passages. The invention also provides instrumentalities for switching the application of the fluid under pressure acting on the vanes at lshe same instant the converter is caused to reverse its direction of rotation.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as speciiically described.

What is claimed is: In a hydraulic power converter the combination comprising a rotor member; said rotor member having a plurality of cam lobes and dwell portions on the outer periphery thereof;

said rotor member being rotatable in either a clockwise or counter-clockwise direction alternativelyas desired;

a stator member enclosing said rotor member in such a manner as to form pressurizable chambers spaced around the circumference of said rotor member by Virtue of the cooperative relationship thereof with the dwell portions of said rotor surface;

said stator member having radially disposed vane chambers located therein circumferentially spaced around the inner portion of said stator member and opening toward said rotor member;

pressure passages within said stator member;

`said pressure passages being located adjacent the sides of each of said vane chambers and communicating with each of said pressurizable chambers and being spaced around said rotor thereby to provide pressure entry and exhaust pressure passages from a source of hydraulic uid to said pressurizable chambers;

vane members slidably disposed within said vane charnbers;

each of said vane members having a portion configured to engage said rotor member to divide each of said pressurized chambers into two portions and a portion within each of said vane chambers disposed to receive pressurized fluid from said pressure passages for biasing said vane member toward said rotor member;

the irst portion of each of said pressurizable chambers forming a chamber for reception of uid under high pressure when said rotor is rotating in a clockwise direction and forming a chamber for exhausting less highly pressurized iiuid when said rotor is rotating in a counter-clockwise direction;

the second portion of each of said pressurizable chambers forming a chamber for exhausting liuid under less than high pressure when said rotor is rotating in a clockwise direction and a chamber for receiving fluid under high pressure when said rotor is rotating in a counter-clockwise direction;

additional passages in said stator in fluid communication with each side of said vane chambers providing fluid communication of biasing iiuid for liow onto the top of said vane members in said vane chambers for biasing said vane members against said rotor with fluid from said first passages, said passages opening into either of said irst or second portions of said pressurizable chamber correlative with the direction of rotation of said rotor whereby said vane is caused to assume a position providing a sealing relationship with a portion of the wall of the vane chamber on the low pressure side thereof, thereby further effecting a sealing relationship between said vanes and the rotor; p

an annular groove in said stator disposed in fluid communication with -said irst mentioned passages, a`

`source and exhaust for pressurized liuid and the respective pressurized chambers located radially outward from said vane members;

means including an O ring disposed for movement in said annular groove for selectively applying iiuid under high pressure through said pressure passages in either said first or said second portions of said chambers to thereby change the direction of rotation t of said rotor;

switching means operably connected to said power converter and cooperative with said O ring in a manner to apply the pressure relationship of hydraulic iiuid under pressure to the same preselected pressurizable chamber and into the respective chambers associated therewith to maintain pressure on the top of said vanes when said rotor is changed from one direction of rotation to the opposite direction of rotation.

References Cited by the Examiner UNITED STATES PATENTS 793,660 7/05 Hinden 91-104 X 807,421 12/ 05 Dickison 103--123 920,976 5/09 Minor 10B-136 2,371,081 3/45 Tucker et al. 103-136 2,786,421 3/57 Prendergast 103--123` 3,008,424 11/61 Roth 103-136 X 3,016,021 1/62 Rincer 103-123 3,076,415 2/63 Farron 10B-123 X FOREIGN PATENTS 346,020 3/31 Great Britain.

KARL I. ALBRECHT, Primary Examine-r.

WILBUR J. GOODLIN, JOSEPH H. BRANSON, JR., Examiners.

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