US3106167A

US3106167A - Machine adapted to operate as pump, compressor or motor

Info

Publication number: US3106167A
Application number: US820233A
Authority: US
Inventors: Bjorklund Gustaf Erik; Edvardsson Svante Roland; Eriksson Rolf Gustaf
Original assignee: Dentatus AB
Current assignee: Dentatus AB
Priority date: 1958-06-24
Filing date: 1959-06-15
Publication date: 1963-10-08
Anticipated expiration: 1980-10-08

Description

5.- E. BJORKLUND ETAL 3,106,167

. Oct. 8, 1963 MACHINE ADAPTED TO OPERATE AS PUMP, COMPRESSOR OR MOTOR g Sheets-Sheet 1 Filed June 15, 1959 INVENTORS GusmF [R/K 5mm u/vo Arry.

Oct. 8, 1963 G. E. BJCRKLUND ETAL 3,106,167

MACHINE ADAPTED TO OPERATE AS PUMP, COMPRESSOR OR MOTOR Filed June 15, 1959 2 Sheets-Sheet 2 VIII/III wrlllll'llf INVENTORS SVA/Vrf Pam/v0 fay/mama v United States This invention relates to a machine adapted to operate as a pump, compressor, motor or the like. The machme comprises a centrally disposed pintle hav ng lnlet and discharge ports, a cylinder block surrounding the pintle and including reciprocable pistons, and a ring surrounding the cylinder block and adapted to rotate aboutan axis disposed excentrically with respect to the p1ntle. In conventional machines of this kind there are provided transmission members which directly transmit motion between the surrounding ring and the cylinder block. Such machines have not worked satisfactorily under all conditions of operation. I

One object of the present invention is to provide 1mproved transmission members between the ring and the cylinder block so as to ensure particularly small mechanical losses and a high efficiency of the machine.

In its broadest aspect the invention is characterized by rolling looking or entraining elements serving as motion transmitting members between the ring and the pistons and adapted to permit reciprocating movement of the pistons and to lock the ring and the cylinder block together on rotation relative to the central pintle.

If the pistons are generally cylindrical, their end faces directed toward the ring and engaging the rolling elements are suitably concave and preferably spherically concave. In a simplified embodiment of the invention, the pistons may be ball-shaped so as to constitute rolling locking elements in direct engagement with concave recesses in the surrounding ring.

To facilitate starting of the machine, it may be suitable to provide springs or other members in a manner such that the pistons are acted upon by radially outwardly directed forces which act also when the machine is being started. Under other conditions of operation, the pressure between the rolling elements and the concave seats required to transmit the input torque is pro duced by the centrifugal forces arising out of the masses of the rotating rolling elements.

A further improvement of the mechanical efficiency is obtainable if the faces of the cylinder block subjected to the pressure of the working fluid and directed toward the pintle are dimensioned such as to relieve the cylinder block of the radial pressures arising from the pistons.

Further features of the invention and advantages obtained thereby will appear from the following description of several embodiments illustrated in the annexed drawing. FIG. 1 is a diagrammatic cross-sectional view of adjacent parts of the cylinder block and the surrounding ring and is intended to explain the movements and positions of the rolling elements relative to the pistons. FIG. 2 is a cross-sectional view of an embodiment. FIGS. 3 and 3a are perspective views of a modified embodiment. FIGS. 4 and 5 illustrate a cross-sectional view and a central longitudinal vertical section, respectively, of a further embodiment of the invention. FIG. 6 is a diagrammatic view of a detail of construction, and FIG. 7 a central longitudinal view of a still further embodiment including means for varying the excentricity of the pintle.

The principle of the mode of operation of the rolling locking elements is illustrated in FIG. 1, but the inventet ice

tion will be first explained with reference to the more complete embodiment illustrated in FIGS. 4 and 5.

Referring to FIGS. 4 and 5, numeral 1 denotes the base of the machine which supports a bearing 2 for the tubular drive shaft 3 of an annular driving member 4 which hereinbelow is termed the ring. The axis of the drive shaft 3 is indicated at 5 in FIG. 4. The drive shaft 3 is in turn mounted on a stationary shaft 6 which by means of a pin 8 is secured to a bracket 7 on the base. The shaft 6 has a journal 9 in the form of a pintle which is disposed within the ring 4. The journal 9 is excenirically arranged with respect to the inner face or trackway 10 of the ring. The axis of the journal is indicated at 11 in FIG. 4. The journal 9 has two diametrically opposed recesses, viz. an inlet recess 12 and an outlet recess 14. By means of a bore 15, the recess 12 communicates with an inlet conduit, not shown, for

. the working fluid, and a similar bore 16 connects the other recess 14 with an outlet conduit. The pintle forms an inlet side and an outlet side in a cylinder block 17. This block 17 is mounted on the journal 9 and has a number of preferably cylindrical bores 18, eight bores being shown in the embodiment. The bores 18 are radi ally directed toward the axis 11 and each bore receives a piston 19. The pistons are reciprocable in the bores in sealing engagement with the walls thereof. Each cylinder space inwardly of the piston can be put into communication with the

recesses

12 and 14 in the journal 9 by means of a port 20.

Between the pistons 19 and the surrounding ring 4 there are provided rolling locking or entraining elements, by means of which the cylinder block can be rotated around the journal 9 by the driving ring. Each piston is associated .with a rolling element, preferably in the form of a ball 21. In order to obtain the desired locking action, at least one of the faces engaged by each rolling element 21 is concave. In the embodiment illustrated in FIGS. 4 and 5, the outer end faces 22 of the pistons are concave, whereas the inner or driving face 10 of the surrounding ring 4 is cylindrical.

The pistons 19 are acted upon by springs 23 provided in the cylinder spaces inwardly of the pistons and tending to move the pistons radially outwardly so as to keep the rolling elements in engagement with the face 10 of the ring 4.

Assuming the ring 4 to be the input member rotating in the direction of the arrow 24 in FIG. 4, the mode of operation of the machine (which here is a pump) is as follows.

If the driving ring 4 rotates, the cylinder block 17 will follow this rotation due to the locking action of the rolling elements 21 in cooperation with the concave faces 22. The springs 23 contribute toward the required frictional engagement between the rolling elements 21 and the

faces

22 and 10. As the rotational speed of the cylinder block becomes higher, the centrifugal forces acting on the pistons and, consequently, the above named frictional engagement will be increased. The movement of the rolling elements will be explained more in detail with reference to FIG. 1.

Since the face 10* of the driving member is disposed excentrically with respect to the journal 9 on which the cylinder block 17 is mounted, each piston 19 will move outwardly in its bore from an inner position to an outer position during one half of a revolution of the cylinder block and will return from the enter to the inner position during the other half of the revolution. For instance, the piston 19a located farthest to the right in FIG. 4 will move from its inner end position illustrated to its outer end position corresponding to the position of the piston 19b located farthest to the left. During this movement, the piston successively passes the positions assumed !by the intermediate pistons in FIG. 4 with the result that working fluid will be successively drawn into the cylinder space inwardly of the piston through the inlet bore 15, the recess 12 and the port 20. During the otherhalf of the revolution, from the position 19b back to the position 19a, the piston moves gradually inwardly, thereby forcing working fluid out of the cylinder space inwardly of the piston through the port 20, recess and outlet bore 16.

It will thus be obvious that the machine can operate as a pump or compressor when the driving member 3, 4 is rotated by means of a motor. If pressure fluid is supplied through the inlet bore, the machine canbe operated as a pressure-fluid driven motor.

During rotation of the ring 4- and the cylinder block 17, the rolling elements 21 will roll to and fro along part of the concave face or raceway 22 and also through a short distance along the surrounding cylinder face or raceway 10, as shown in FIG. 1 where the paths along which the rolling elements move are marked by heavy lines a and b on the faces and 22, respectively.

It can be proved that the condition for the transmission of torque from the face 10 to the rolling element satisfies the equation Egg where E is the excentricity of the driving face 10 with respect to the journal 9, R is the radius of the driving face and f is the coeflicient of friction.

As to the concave face 22, we have tan 7 R d1 Where 'y is the angle between the direction of the force acting between the rolling element and the concave face and'the direction of movement of the piston in the cylinder block, and d is the diameter of the rolling element.

In FIG. 1 there are shown four positions A, B, C, D of a rolling element. In the position C, the rolling element assumes its greatest distance from the central or lowest point of the concave face. In the position A, the resultant force which transmits the torque from the face 10 to the cylinder block 17 is equal to zero.

The pistons and rolling elements may be replaced by balls which act as locking elements, as exemplified in FIG. 2 where these elements or balls are indicated at 26. To obtain the desired locking action, the face 10 of the surrounding ring must have recesses 27 for cooperation with theihalls, said recesses having a suitable radius of curvature. This radius of curvature should be as great as possible in view of the movement of the spherical piston. The mode of operation of the embodiment shown in FIG. 2 is similar to that described with reference to FIGS. 4 and 5. The construction according to FIG. 2 is most suitable for machines serving as pneumatic Inoto-rs. This construction may be modified 'by replacing the concave cavities or recesses 27 by oblong slots 27 in the ring 4, which slots have pointed ends, as illustrated in FIGS. 3 and 3a in which the shaft 3 of the ring is mounted in ball bearings 28. This construction may be used for very small units devised for high speeds, such as 100,000 rpm. or even more.

It is often desired to vary the capacity of a pump or motor at constant speed. In a machine according to the invention, such variation can be easily effected by varying the piston displacement which is direct-1y proportional to the distance between the axes of the driving ringand the cylinder block and which, consequently, can be altered by variation of the excentricity of the journal serving as a pintle with respect to the surrounding ring.

In FIGS. 6 and 7 there is shown a construction which enables variation, from zero to a certain positive or negative value, of the excentricity of a journal 30 serving as a pintle and a support for the cylinder block 17. The journal 30 is secured to a T-shaped slide 31 which is displaceable along a T-shaped track formed by guides 32 which are attached to the inner side of cover 36 which forms part of surrounding casing 34 of the machine. The cover has an opening 35 through which extends a central projection 36 of the slide 31. This projection is formed with a threaded sleeve 37 which receives a screw 38. The screw is mounted for turning but not for axial displacement in a flange 39 on the cover and can be turned by means of a knob 40. A sealing member 41 effects a seal between the cover 33 and the slide 31 around the opening 35. Inlet and outlet conduits 4-2 with hoses for the working fluid can be connected to the projection 36 which has corresponding bores or ducts communicating with the

recesses

12, 14 in the journal 30 a manner similar to that described with reference to FIGS. 4 and 5. When the screw 38 is turned, the slide 31 is moved up or down along the track 32 the location of which is such that the axis 11 of the journal 30 coincides with the axis 5 of the driving ring 4 or is spaced apart therefrom in accordance with the desired excentrioity and capacity of the machine.

A pump, compressor or ,motor devised as described above is able to operate at very high efiiciencies. As a matter of fact, losses due to leakage are exceedingly small even if the working fluid is a highly liquid oil and the working pressure is high (for instance 700 to 1,400 pounds per square inch). Further, friction between the movable parts is reduced to an absolute minimum.

The faces acted upon by the pressure of the working fluid can be readily dimensioned such that the cylinder block will rotate on the journal practically without any hearing pressure. This is due to the fact that the radially inwardly acting forces of the pistons may be balanced by the outwardly acting forces in the

recesses

12, 14 of the journal. This means that apart from mere liquid-fluid friction the reaction torque of the cylinder block, which corresponds to the input torque of the ring 4, arises in a system in which sliding friction is of extremely small significance.

The simplest constructions having low losses and high efficiencies are obtainable if the surrounding ring is the input member when the machine is a pump or compressor, and the output member when the machine is a motor.

What we claim is:

l. A machine of the type described comprising a centrally disposed pintle having inlet and discharge ports, a cylinder block having bores therein surrounding said pintle and rotatable relative thereto, said bores communieating with said inlet and discharge ports, pistons mounted in said bores and reciprocably movable therein, a ring member surrounding said cylinder block and rotatable about an axis disposed eccentrically with respect to the axis of said pintle, rotatable means operatively connected to said ring member in driving or driven relation therewith, said pistons having disposed at the ends remote from the axis of said pintle continuously tapering concave locking surfaces, said ring member having a surface disposed opposite said concave locking surfaces of said pistons, and entrain-ing locking roller means disposed between said surface of said ring member and said concave locking surfaces, said concave locking surfaces having a substantially greater radius of curvature than that of said roller means so that said roller means are movable therein while said ring member is rotating thereby transmitting motion between said ring member and said pistons and permitting reciprocating movement of said pistons and locking of said ring member and cylinder block together rotatively relative to said pintle to transmit a liquid from said inlet port to said outlet port.

2. A machine according to claim 1 in which means are operatively connected to said pintle to adjust the eccentricity thereof relative to the axis of said cylinder block so as to vary the capacity of said machine.

3. A machine according to claim 1 in which spring 5 means are disposed Within said bores against said pistons to urge same toward said ring member.

4. A machine according to claim 1 in which said entraining locking roller means are spherical.

References Cited in the file of this patent UNITED STATES PATENTS Johnson Sept. 13, 1949 Sorensen May 30, 1956 Dannevig Apr. 21, 1959 FOREIGN PATENTS Ger-many Nov. 29. 1956

Claims

1. A MACHINE OF THE TYPE DESCRIBED COMPRISING A CENTRALLY DISPOSED PINTLE HAVING INLETAND DISCHARGE PORTS, A CYLINDER BLOCK HAVING BORES THEREIN SURROUNDING SAID PINTLE AND ROTATABLE RELATIVE THERETO, SAID BORES COMMUNICATING WITH SAID INLET AND DISCHARGE PORTS, PISTONS MOUNTED IN SAID BORES AND RECIPROCABLY MOVABLE THEREIN, A RING MEMBER SURROUNDING SAID CYLINDER BLOCK AND ROTATABLE ABOUT AN AXIS DISPOSED ECCENTRICALLY WITH RESPECT TO THE AXIS OF SAID PINTLE, ROTATABLE MEANS OPERATIVELY CONNECTED TO SAID RING MEMBER IN DRIVING OR DRIVEN RELATION THEREWITH, SAID PISTONS HAVING DISPOSED AT THE ENDS REMOTE FROM THE AXIS OF SAID PINTLE CONTINUOUSLY TAPERING CONCAVE LOCKING SURFACE, SAID RING MEMBER HAVING A SURFACE DISPOSED OPPOSITE SAID CONCAVE LOCKING SURFACES OF SAID PISTONS, AND ENTRAINING LOCKING ROLLER MEANS DISPOSED BETWEEN SAID SURFACE OF SAID RING MEMBER AND SAID CONCAVE LOCKING SURFACES, SAID CONCAVE LOCKING SURFACES HAVING A SUBSTANTIALLY GREATER RADIUS OF CURVATURE THAN THAT OF SAID ROLLER MEANS SO THAT SAID ROLLER MEANS ARE MOVABLE THEREIN WHILE SAID RING MEMBER IS ROTATING THEREBY TRANSMITTING MOTION BETWEEN SAID RING MEMBER AND SAID PISTONS AND PERMITTING RECIPROCATING MOVEMENT OF SAID PISTONS AND LOCKING OF SAID RING MEMBER AND CYLINDER BLOCK TOGETHER ROTATIVELY RELATIVE TO SAID PINTLE TO TRANSMIT A LIQUID FROM SAID INLET PORT TO SAID OUTLET PORT.