EP0211884A1

EP0211884A1 - Radial piston rotary machine capable of forming a pump or an engine

Info

Publication number: EP0211884A1
Application number: EP86901123A
Authority: EP
Inventors: Stefano Speggiorin
Original assignee: HYDRO-MEC Srl
Current assignee: HYDRO-MEC Srl
Priority date: 1985-02-15
Filing date: 1986-02-04
Publication date: 1987-03-04
Also published as: WO1986004961A1; IT8585514A0; AU5451786A; IT1187501B

Abstract

La machine comprend une carcasse (1-2) qui porte un roulement excentré (10) à l'intérieur duquel tourne un rotor (3) monté sur un arbre (4) et muni de pistons radiaux (9). Ceux-ci sont reliés par l'intermédiaire d'un distributeur (12) à deux conduits extérieurs (17, 18) qui assurent la liaison de la machine soit avec le réservoir d'huile et le dispositif d'utilisation lorsque l'ensemble fonctionne à la manière d'une pompe, soit avec l'amenée d'huile sous pression et le réservoir de décharge lorsque ledit ensemble fonctionne à la manière d'un moteur.The machine comprises a carcass (1-2) which carries an eccentric bearing (10) inside which turns a rotor (3) mounted on a shaft (4) and provided with radial pistons (9). These are connected via a distributor (12) to two external conduits (17, 18) which ensure the connection of the machine either with the oil tank and the operating device when the assembly is operating in the manner of a pump, or with the supply of oil under pressure and the discharge tank when said assembly operates in the manner of a motor.

Description

RADIAL PISTON ROTATING MACHINE CAPABLE OF FORMING PUMP OR MOTOR -

The subject of the present invention is a machine of the reversible type, capable of functioning as well as a pump as with that of a motor, and the essential novelty of which is to include radial pistons associated with an automatic front distributor. -balanced.

STATE OF THE ART

Modern technology presents in the oleodynamic sector a wide range of machines of the reversible type suitable for forming motors or pumps. The constructions currently on the market can basically be divided into three categories, the differentiation of which is mainly based on the price / performance ratio.

The first category brings together motors and pumps which work at low pressures of the order of 50 to 100 bars and at speeds varying from 50 to 750 revolutions / minute. These machines are mainly of the vane or orbital rotor type and their cost is clearly limited; they are generally used in agriculture or in light industrial applications. Owing to their constructive characteristics, they have a low volumetric and mechanical efficiency, as well as a limited period of use.

The second category includes reversible machines most often fitted with axial pistons, allowing high speeds (from 200 to 3000 revolutions), as well as notable performances (from 100 to 150 bars). When used as hydraulic motors, they are generally associated with planetary gearboxes and are used in mobile applications and in various industrial vehicles. Their complicated and costly construction, together with their high operating noise, limit their use to the industrial sector of different operating machines.

Finally the third category mainly brings together radial piston engines which, owing to their high pressures and their low number of revolutions, are used whenever it is necessary to develop high mechanical torques, sometimes dispensing with the use of speed reducers. These motors have considerable dimensions and weight, so that they are mainly applied to certain types of heavy vehicles, winches or machines for working plastics; it goes without saying that their inability to operate at high rotational speeds and to carry out rapid and frequent reversals of gait considerably limits their other applications.

DEFINITION OF THE INVENTION

The fundamental object of the present invention is to allow the production of a reversible type machine, capable of functioning both as a pump and as a motor and whose new characteristic is to be equipped with radial pistons whose heads are held against the inner ring of a bearing arranged eccentrically to the axis of rotation of the assembly, so that during a rotation of 180 ° said pistons act at suction while during 180 ° following they act on compression. "

A suitable distributor provided at the front end of the rotor makes it possible to connect the cylinders of a sector to the pressurized oil supply duct, the cylinders of the opposite sector being likewise joined to the discharge duct, so as to allow thus the operation of the machine like a motor; by reversing the arrangement of the aforementioned distributor, the cylinders of one sector are connected to the oil tank through a conduit which then acts as a suction conduit, while the cylinders of the other sector are joined by a conduit of compression, the whole so as to obtain the functioning of a pump.

Tests have shown that the machine according to the invention was capable of reaching very high number of revolutions under considerable operating pressures, and with a yield and an operating time such that the assembly becomes capable of being applied in the industrial field of operating machines as motors or pumps, tαut remaining able to suit typical uses of the above categories, due to their low operating noise as well as their working capacity, even in the case of overloads or frequent reversals. The machine according to the invention has a particularly simplified structure while providing performan¬ these which can only be obtained using machines with axial pistons, and having much smaller dimensions and weight compared to these. . With a significant simplification in terms of construction, performance can be obtained which cannot be provided by other rotary machines with radial pistons, in particular in use as motors.

LIST OF FIGURES

The invention will now be described in more detail, with reference to the accompanying drawing in which:

Fig. 1 is an axial section "of a rotary machine according to the invention.

Fig. 2 is an elevational view from the front, along arrow II of FIG. 1.

Fig. 3 is a cross section along the plane indicated in III-III in FIG. 1.

Fig. 4 is an "exploded" axial view. Fig. 5 is an elevational view of the dispenser, along the arrow V of FIG. 4.

Fig. 6 shows the opposite face of this dispenser, along arrow VI of FIG. 4.

Fig. 7 and 8 illustrate in partial section two alternative embodiments of the rotary machine according to the invention. SPECIFIC EMBODIMENTS

As shown in fig. 1 the machine according to the invention essentially comprises two housings 1 and 2 which constitute a carcass inside which is housed a rotor 3 mounted on a shaft 4; forward this is associated with a cable gland 5 and is supported laterally by a bearing 6 separated from a thrust bearing 8 by an annular spacer spacer 7. In the rotor 3 are formed cylindrical cavities to inside of which radial pistons 9 move which are capable of coming into contact with the inner ring of a bearing 10 mounted eccentrically relative to the rotor 3 and to the shaft 4. A similar bearing 11 carried by the rotor 3 ensures the support of the rotating assembly.

The rear housing 1 contains one of the most important organs of the machine, namely the distributor referenced 12.

The latter is formed by a disc in which are mounted four small perforated balancing pistons 13 which are provided with an annular seal 14 and a thrust spring 15, which tends to keep each piston applied against the internal face of the housing 1. It will be observed that the latter is hollowed out from conduits 16 (fig. 5) connected on one side to a conduit 17, from., the other to a conduit 18 (fig. 2).

Depending on whether the machine operates as a pump or as a motor, the conduits 17 and 18 can be connected, in the first case to the oil tank, respectively to the discharge conduit, in the second to the arrival of pressurized oil, respectively to the discharge line.

In the case of pump operation, half of the pistons 9 which move along the arc between the points E and F (fig. 3) in the direction indicated by the arrow A in fig. 3, will compress the oil thus discharged into the conduit 17 while the other half of said pistons 9 which move between points F and E according to the same arrow A, are driven out under the action of centrifugal force by sucking l through the line 18. On the other hand, in the case of engine operation, the pressurized oil acts, through the conduit 18, on the pistons which move along the half-circumference between F and E, to be discharged into the oil tank at through the conduit 17 by the pistons which move along the arc between E and F.

The springs 15 ensure on the one hand the perfect application of the small pistons 13 against the internal front face of the rear housing 1 during the initial phase, on the other hand the close adhesion of the distributor 12 against the head of the rotor 3 while being thus with any passage of oil between the surfaces in contact, which allows obtaining a maximum output for the machine.

In fact, the essential characteristic of the dispenser described is to be self-balanced for each type of operation, thereby ensuring optimum performance for all regimes.

In fact, as a result of the operating pressure, the small pistons 13 push the distributor 12 against the front face of the rotor 3, which has the effect of supporting the thrust exerted axially on said rotor by the bearing 8, d on the other hand to ensure the self-balancing of the assembly and the hydraulic seal in the frontal direction as in the radial direction with respect to the conduits 17 and 18.

Fig. 5 and 6 allow a good understanding of the arrangement of the distributor 12. In FIG. 5 in particular we see the arcuate conduits 16 which then widen in the cylindrical cavities 16 '(fig. 6) containing the small balancing pistons 13 of fig. 4.

Still in fig. 5 two cylindrical cavities 26 and 27 will be noted formed in the face of the distributor 12 which is in contact with the rotor 3, in order to improve lubrication in the zones comprised between the conduits 16, that is to say at the level of the parts who are not interested in these. Cavities 28 formed inside the outer ring 29 constitute small oil reservoirs which are such as to facilitate the rolling of the oil in the space between the head of the rotor and the adjacent surface of the distributor 12.

In the construction variants illustrated in fig. 7 and 8, the machine comprises two rows of pistons arranged in two different planes. In fig. 7 two separate bearings 19 are provided, separated from each other by a spacer 20; against these bearings apply the pistons 21 of the two parallel rows carried by a single rotor 22. In fig. 8 the two rows of pistons 24 mounted on the rotor 25 cooperate with a single bearing 23, obviously provided wider for this purpose.

It will be understood that in both of these two variants with two rows of pistons the operation remains identical to that described for the machine with a single row.

OPERATION OF THE MACHINE

In the foregoing description, it has been indicated that the machine is capable of operating either as a pump or as a motor. Indeed the machine is perfectly reversible, without it being necessary to resort to modifications on the constructive level.

For operation as a pump, the part of the shaft 4 which protrudes outside the machine is connected to an actuation motor, for example ⁵ electric, capable of animating the rotor 3 with a rotational movement, of so that the pistons 9 are held by centrifugal force applied against the inner ring of the bearing 10. Thanks to the distributor 12, the oil sucked in through the conduit 18 when the pistons 9 are in the arc of a circle between the points F and E of fig. 3 is discharged by said pistons into the conduit 17 when they are in the arcuate part which goes from point E to point F.

The oil flow rate obtained when the machine operates as a pump depends on the speed of rotation of the rotor 3 as well as on the number and dimensions of the pistons 9. For operation as an engine, the oil under pressure enters the machine for example through the conduit 18 by determining a thrust action on the pistons which Are in the arc between F and E of fig. 3, the direction of rotation being that defined by arrow A. This oil is returned through the conduit 17 when the pistons are in the arc between E and F, always in the same direction of rotation.

In summary, by properly supplying pressurized oil to the conduit 18, it is possible to rotate the rotor 3 and with it the shaft 4 of which it is integral. By suitably varying the flow rate and pressure of the oil, it is possible to modify the engine torque and the number of revolutions of the engine within wide limits, that is to say in fact the mechanical power supplied by it. this.

It should moreover be understood that the foregoing description has been given only by way of example and that it in no way limits the field of the invention from which one would not depart by replacing the execution details described by all other equivalents.

Claims

1. Rotating machine with radial pistons, comprising a carcass formed by two opposite housings (1, 2) assembled in leaktight manner and inside which is mounted a rotor (3) wedged on a shaft (4), characterized in that that in the rotor body (3) are formed cylindrical cavities inside which move pistons (9) which during the operation of the machine are in contact with the inner ring of a bearing mounted in the carcass so eccentric with respect to the axis of rotation of said rotor, the latter being associated with a distributor (12) which places two external conduits (17 and 18) in communication respectively with the cylindrical cavities arranged in a circular arc of 180 °, thus that with the cylindrical cavities arranged at the level of the opposite circular arc, thus making it possible to use the machine either as a pump connecting one of the conduits (17 or 18) to an oil tank while the other cond uit is connected to a device for the use of oil under pressure, either as a motor by connecting one of the conduits (17 or 18) to the supply of pressurized oil while the other conduit , is connected to a discharge container.

2. Machine according to claim 1, characterized in that the distributor is formed by a disc (12) kept fixed in the carcass at the level of the internal bearing thereof in which the conduits (17, 18) are formed and which is in contact with the front face of the rotor (3), which disc is hollowed out with cylindrical cavities (16 ') formed in the face of said disc which is in contact with the carcass, said cavities being placed in communication with the arcuate conduits ( 16) provided in the opposite face of the disc which is in contact with the rotor (3), thus allowing the communication of the conduits (17, 18) with the two rotating sectors in which the cylindrical cavities in which the pistons move are formed (9).

3. Machine according to claim 2, characterized in that each cylindrical cavity (16 ') of the distributor (12) is equipped with a perforated piston (13) associated with a spring (15) which applies said distributor against the rotor (3), while said pistons are held in contact with the internal plane of the carcass on which are formed the conduits (17, 18) which connect the machine to the outside, ensuring in this way the self-balancing of said distributor.

4. Machine according to any one of claims 2 and 3, characterized in that in the face of the distributor (12) which is in contact with the rotor (3) are formed cavities (26, 27) located in the spaces included between the conduits (16), as well as cavities (28) provided along the circular crown (29) external to the active zone of the distributor in order to improve the displacement of the rotor (3) against the adjacent surface of said distributor.

5. Machine according to any one of claims 1 to 4, characterized in that the radial pistons (9) are arranged in two parallel annular rows by being connected to the same distributor (12).