ITMO20110001A1 - HYDRAULIC RADIAL CYLINDER MACHINE WITH PERFECT OSCILLATING CYLINDER - Google Patents

Description

RADIAL CYLINDER HYDRAULIC MACHINE WITH PERFECTED OSCILLATING CYLINDER.

DESCRIPTION

Field of application

The present invention refers to a hydraulic machine with oscillating radial cylinders, i.e. an improved oscillating cylinder, of the type known in the art, for a hydraulic machine with radial cylinders, where cylinders arranged in a star shape and all acting on the same eccentricity or crankshaft elbow they are placed in oscillation with respect to the body of the machine. The oscillating radial cylinder, object of the attached description, has improved characteristics with respect to the known art of radial hydraulic machines so as to achieve relevant technical-economic results with respect to it.

Known art

The state of the art includes various types of radial hydraulic machines with cylinders arranged in a star shape and in particular includes those in which the single cylinder oscillates around an axis, close to the outer diameter of the skirt of the hydraulic machine, in order to be able to perform the required oscillation. from the crankshaft on which it is in contact and operates with its rotational motion. This oscillation is required since the cylinder-piston complex, even though it is subject to the reciprocating motion of the displacement, it performs the functions of "connecting rod" in the mechanical concept of a thrust crank, which oscillates to follow the evolution of rotation of the crank pin, ie of the elbow or eccentricity of the crankshaft; the so-called "connecting rod" therefore has a variable length according to the development of the displacement with the motion of the liquid from or towards it, the affected oscillating radial cylinder. The respective piston is placed to slide on the external surface of the elbow or eccentric, or mediated with concentric organs interposed, but which rotate with it.

In the technique, as mentioned above, these hydraulic machines are made in various ways of supporting the cylinder oscillating: the first by means of lateral tangs, placed on an axis of oscillation parallel to the axis of the crankshaft and positioned next to the outer shell of the machine, they allow the passage of the hydraulic oil through one of them shanks, so as to position the bulkier part of the cylinder, the liner and its outer shell away from the elbow and obtain greater displacements with the same overall dimensions, while the passage of the hydraulic oil in the shank makes it weak at the high operating pressures, now common in the field of this type of hydraulic machine; a second way of oscillating the cylindro-piston complex in the hydraulic machine is to support the cylindro-piston complex on a spherical surface, for each cylinder, located near the outer diameter of the hydraulic machine shell.

In this second oscillation mode of the cylinder-piston assembly, the supply and passage of the hydraulic liquid to and from the cylinder takes place from the outside of the spherical oscillation surface, i.e. it is achieved by necessarily increasing the diameter of the jacket or its overall dimensions, from do not allow the containment and limitation of the overall dimensions of the hydraulic machine, which becomes more evident and penalizing, especially when it is planned to carry out large sizing such as to be able to achieve high displacements and flow rates of hydraulic fluid that pass through the hydraulic machine.

In fact, a notable advantage of radial cylinder hydraulic machines, which notoriously allow a better performance than other types of known hydraulic machines, is that of having a large displacement in overall dimensions, i.e. producing high torques without working at high pressures of the hydraulic fluid, and, at the same time, to be able to work even at high rotation speeds, that is, to achieve a maximum flexibility of use not previously achievable with hydraulic machines of another type. A further limitation is inherent in the known art: in the increase in the passage of the ports and channels for feeding and / or discharging the hydraulic liquid, now not possible except by increasing the overall dimensions; in reducing the length of the channels themselves, so as to reduce the noxious volume which is known to generate noise, due to the constant pressure variation of the column of liquid contained therein, and therefore loss of power; in the reduction of the external dimensions of the machine, with the same displacement and mechanical performance, which make it preferred by users, due to the ease of accommodation in limited spaces and with very reduced dimensions.

Moreover, in the second way of supporting the oscillation of the radial cylinders, as mentioned, the spherical surfaces are large and made in such a way as to contain a pipe of hydraulic liquid to obtain the hydrostatic support of the cylinder, with its spherical surface resting on the surface. spherical made or applied to the outer shell of the hydraulic machine. The hydrostatic support of this meatus does not work in the best of conditions as the hydraulic liquid remains trapped in it especially when the cylinder oscillation angle is reduced, during the control of the variation of the displacement known for this type of machines: the meatus must have an annular surface under pressure of adequate amplitude to operate correctly, while the pressure of the hydraulic fluid is elevated when using the hydraulic machine, as often happens in motors operated at minimum displacement, therefore made with larger dimensions of the surface with the meatus, so as to reduce the passage of the hydraulic liquid which, as mentioned, occurs from the inside of the annular spherical oscillation surface.

This state of the art is susceptible of further improvements with regard to the possibility of realizing an improved radial hydraulic machine, of the oscillating cylinder type, which overcomes the aforementioned drawbacks and makes the spherical contact between the cylinder and the body functional for the reduction of the overall dimensions and the masses involved. or casing of the hydraulic machine.

The technical problem, therefore, underlying the present invention is that of realizing an improved radial hydraulic machine of the oscillating cylinder type in which the cylinder-piston assembly is in contact with the motor body, or skirt, realizing sizing in the spherical contact in so as to avoid unnecessary increase in the external dimensions of the hydraulic machine, when it is desired to obtain greater displacements and / or large liquid flow rates, taking into account the known technical advantages, which the hydraulic machines with radial cylinders with oscillating cylinders have achieved and which, with the change of the way of making the spherical contact of oscillation, they can achieve in the sought improvement of reduction of the overall dimensions.

A further and not least object of the present invention is to allow the realization of a radial hydraulic machine of the type with oscillating cylinders in which in the reduction of the dimensions with the same displacement or, vice versa, with the same dimensions, with an increase in the displacement obtained, it is possible to reduce the harmful volumes present in the supply / exhaust pipes to and from the cylinders. Finally, a further part of the aforementioned technical problem concerns the realization of an improved radial hydraulic machine of the type with oscillating cylinders in which the section of the supply / exhaust ducts of the cylinders can be increased so as to make the passage easier and more effective. of hydraulic fluid from the system to the cylinders and vice versa, with the aim of allowing flow rates greater than those achievable in the constructive solutions present in the known art.

Summary of the invention

This problem is solved, according to the present invention, by a hydraulic machine with radial cylinders, comprising radial cylinders oscillating in proximity to the outer skirt of the crown or star of cylinder-piston groups; the pistons of said units are made to slide on a crankshaft or eccentric shaft, or on interposed members concentric thereto, and perform the reciprocating motion in the oscillating cylinders; characterized in that it has said oscillating cylinders placed in contact with a spherical surface of oscillation formed or brought back into the body or shell of the hydraulic machine; each oscillating radial cylinder being provided with an internal annular surface with a curvature greater than the radius of the spherical oscillation surface, for coupling with said spherical oscillation surface to make contact on a circumference having a band width due only to elastic yielding of the materials in the area of the contact circumference; finally, there are means for pushing the oscillating cylinders against the spherical surface of oscillation.

Furthermore, in an improved constructive embodiment: the spherical surface of oscillation has a limited annular conformation in the vicinity of the median contact area around the circumference of contact with the internal annular surface.

In a further and advantageous constructive form: the spherical oscillation surface has a limited annular conformation in the vicinity of a median contact area around the circumference of contact with the internal annular surface consisting of an internal frusto-conical surface and said truncated surface -internal cone has a limited annular conformation near the median area of contact with the spherical oscillation surface.

Finally, in a further constructive form: the spherical oscillation surface and an internal arcuate annular surface both have an annular conformation limited to the narrow median contact area around the contact circumference between them, the oscillation surface of the radial hydraulic cylinder; the radius of curvature of the internal arcuate annular surface being greater than the radius of the spherical surface of oscillation up to a value less than infinity.

The characteristics and advantages of the present invention, in the realization of a radial hydraulic machine of the type with improved oscillating cylinders, are mentioned in the description given below, of some schematic examples of embodiment given by way of non-limiting example, with reference to the six tables drawing attached.

Brief description of the drawings

- Figure 1 represents a schematic section on a diametrical plane passing through the axis of the crankshaft, in correspondence with an oscillating cylinder at the top dead center, of a radial hydraulic machine equipped with the spherical oscillation support with limited contact, according to the present invention, and simultaneously with the supply on the side of the cylinder; Figure 2 represents an enlargement of the schematic sectional portion II of Figure 1;

Figure 3 represents an enlargement of a schematic sectional portion, as II of Figure 1, but for a spherical oscillation support of a hydraulic machine with radial cylinders with usual feeding from the inside of the spherical annular oscillation surface;

- Figure 4 represents the parameters of the contact sizing in a schematic section of a generic oscillating cylinder of a hydraulic machine with oscillating radial cylinders, equipped with the limited contact coupling according to the present invention;

Figure 5 represents the parameters of the contact sizing in the schematic section of the oscillating cylinder of the hydraulic machine of Figures 1 and 2, equipped with the limited contact coupling here in the spherical-conical shape according to the present invention;

- Figure 6 represents a schematic section of the oscillating cylinder on a diametrical plane, as in Figure 5, but with the indication of the enlargement of the conical surface for the oscillation contact with a spherical surface according to the invention;

- Figure 7 represents a perspective view of the cylinder with side feed, for the radial hydraulic machine of Figures 1, 2 and 5, above;

Figure 8 represents an enlargement of the schematic sectional portion VIII of Figure 6;

- Figure 9 represents a schematic section on a diametrical plane passing through the axis of the crankshaft, in correspondence with an oscillating cylinder at the bottom dead center, of a radial hydraulic machine equipped with the spherical oscillation support with limited contact, according to a further constructive form of the present invention, also with feeding on the side of the cylinder;

Figure 10 represents an enlargement of the schematic section portion X of Figure 9;

- Figure 11 represents a schematic section of an oscillating cylinder on a diametrical plane, of a hydraulic machine according to the invention with the oscillation contact as in Figure 9, with the parameters of the dimensioning of the oscillation contact of a spherical surface according to a further shape the invention is constructive, against an internal arcuate annular surface in the bottom of the oscillating hydraulic radial cylinder.

Detailed description of a preferred embodiment

In Figure 1, in a constructive form of an improved oscillating cylinder, according to the invention, a driving shaft 1 equipped with an elbow or crank 2 on which the pistons 3 of the oscillating cylinder-piston units 4 of the hydraulic machine 5 with oscillating cylinders rest are visible radial 6. The pistons 3 are made to slide on the crank 2 in a known way, by means of respective shoes 7 and retaining rings 8. Each oscillating cylinder 6 is coupled in oscillation with the body 10 of the hydraulic machine 5, by means of a spherical coupling between a member mechanical applied 12 with a spherical annular surface 13, made axially adjustable in a direction parallel to the drive shaft 1, and an internal truncated conical annular surface 14 made on the external surface of the bottom 15 of the oscillating cylinder 6.

The cylinder 6 has on two external lateral surfaces 16 and 17, parallel to each other, a feed hole 18, on the side of the parallel surface 16, and a similar thrust compensation hole 19, on the side of the parallel surface 17: the two surfaces parallel external faces face analogous sliding surfaces 20 in the cover 11 and 21 in the body 10 of the hydraulic machine 5, the body connected to the assembly. The contact between the sliding surface 20, on the cover 11, and the corresponding parallel external lateral surface 16 of the cylinder 6, in the contour of the feeding hole 18, takes place by means of a sealing ring 23 with a metal contact surface; similarly, in the contact between the sliding surface 21 on the body 10 of the hydraulic machine 5, on the opposite side of the cylinder 6, it occurs by means of an identical sealing ring 23 with a metal contact surface. In correspondence with the lateral external surfaces 16 and 17 there are means for thrusting the oscillating cylinders against the spherical oscillation surface, at the lower edges thereof, here comprising on both surfaces an arcuate step 24, with a curvature corresponding to the annular oscillation surface spherical 13 of the cylinder 6, which engage in corresponding arched abutments 25 made on a ring 22 for each side of the cylinder-piston groups 4, with the purpose of maintaining the contact position between the spherical annular surfaces of oscillation 13, of the member mechanically applied 12, and the internal frusto-conical surface 14 of the bottom 15 of the oscillating cylinder 6, upon starting and in the absence of pressure of the liquid in the cylinder. The mechanical member 12, with the spherical annular oscillation surface 13, is made mobile, to allow an adjustment of contact between the lateral external surfaces 16 and 17 and the sliding surfaces 20 on the cover 11 and 21 on the body 10 of the machine. hydraulic system 5, by means of a sliding coupling with pins 31, for a short distance in a direction perpendicular to the plane of oscillation of the oscillating cylinders 6, so as to achieve the best possible seal between the lateral external surfaces and the sealing rings 23 in the respective seats 32, of the rocking cylinder 6.

The hydraulic machine also comprises in correspondence with the feed hole 18, in the cover 11, a feed channel 26 connected to a rotating disc distributor 27 of a type known in the art, placed in synchronous rotation with the drive shaft 1 by means of a front coupling 28 also known.

The realization of the support between the oscillating cylinder and the body or shell of a hydraulic machine, according to the invention, can also take place in a known way with the cylinder feeding channel through the known spherical oscillation surface. Figures 3 and 4 show an application to the aforesaid known way of feeding, with oscillating support of the cylinder according to the present invention in which: a piston 33 is made sliding in an oscillating cylinder 34; the cylinder 34 is equipped with a bottom 35 on the surface of which an internal frusto-conical annular surface 36 is made, placed in contact with a spherical annular surface 37, in turn made on an inserted element 38, or made in one piece, on the body or shell 39 of a hydraulic machine in which feeding occurs in a known way through a channel 40, made in proximity to the axis of said spherical annular surface 37. Also in this oscillating cylinder 34 there are means for pushing the oscillating cylinders against the surface spherical oscillation, even if not shown in Figure 4, on both external sides of the oscillating cylinder 34 in order to maintain the contact position between the spherical annular surfaces of oscillation 37, on the mechanical element 38, and the truncated surface internal conical 36 of the bottom 35 of the oscillating cylinder 34, at start-up and in the absence of pressure of the liquid in the cylinder.

The dimensioning of the spherical annular surface must be provided in relation to the diameter of the cylinder D, or bore, that is the diameter D1 of the spherical surface of oscillation in contact with it, must be smaller than the bore diameter D of the oscillating cylinder 6 or 34. Furthermore, , the semi-opening angle β of the truncated conical annular surface 14 or 36 must be between 4 ° and 60 ° sexagesimal degrees, so then the radius R1 can be dimensioned to make the contact circumference fall between the two annular surfaces spherical and frusto-conical in proximity to the median zone 42 of the truncated conical annular surface 14 or 36, having the desired radius R2.

In Figures 9, 10 and 11 it is visible in a hydraulic machine 41 with oscillating radial cylinders, similar to that of Figure 1, in which the parts with the same function are indicated with the numerical references of Figure 1. The cylinder-piston units 43 here they are formed by a cylinder 44 and a piston 45 equipped with a shoe 46, sliding on the crank 2, and kept in contact with it by retaining rings 8. The cylinder 44, constituting thrust means for contact on a spherical surface of oscillation 47, has arcuate fins 48 housed in arcuate seats 49, obtained in the body 50 and in the relative cover 51 of the hydraulic machine 41.

The cylinder 44 has on two external lateral surfaces 52 and 53, parallel to each other, a feed hole 54, on the side of the parallel surface 16, and a similar thrust compensation hole 55, on the side of the parallel surface 53: the two surfaces parallel external faces face analogous sliding surfaces 56 and 57 in the body 50 of the hydraulic machine 41 and on the cover 51 the body connected to the assembly to it. The contact between the sliding surface 57, on the cover 51, and the corresponding parallel external lateral surface 56 of the cylinder 44, in the contour of the feed hole 54, takes place by means of a sealing ring 58 with a metal contact surface; similarly, in the contact between the sliding surface 56 on the body 50 of the hydraulic machine 41, on the opposite side of the cylinder 44, it occurs by means of an identical sealing ring 58 with a metal contact surface.

Each oscillating cylinder 44 is coupled in oscillation with the body 50 of the hydraulic machine 41, by means of a spherical coupling between a mechanical member 59 with a spherical annular surface of oscillation 60, made axially adjustable in a direction parallel to the drive shaft 1, and a surface internal arcuate annular 61 made on the external surface of the bottom 62 in the oscillating cylinder 44. Furthermore, the mechanical member 59 with the spherical annular oscillation surface 60 is made mobile, as mentioned, to allow an adjustment of contact between the lateral external surfaces 52 and 53 and the sliding surfaces 56 and 57 on the body 50 and on the cover 51 of the hydraulic machine 41, by means of a sliding coupling with pins 63, for a short distance in a direction perpendicular to the oscillation plane of the oscillating cylinders 44, so as to achieve the best possible seal between the lateral outer surfaces and the sealing rings 58 in the respective seats 64 in the body 50 or in the cover 51 of the hydraulic machine 41.

The dimensioning of the internal arcuate annular surface 61, in this further embodiment of the contact with the spherical surface for oscillation, must be provided in relation to the diameter of the cylinder D, or bore, i.e. the diameter D1 of the spherical surface of oscillation 60 contact with it, must be smaller than the bore diameter D of the oscillating cylinder 44. Furthermore, the radius of curvature R3 of the internal arcuate annular surface 61 must be greater than the radius R1, otherwise the contact limited to a circumference is not made, and less than the infinite value (°°), which corresponds to a truncated conical surface, and also to make the contact circumference between the two surfaces fall in proximity to a median area 42 of the internal arched annular surface made in the bottom 62, so as to obtain a sought-after radius R2 of the contact circumference.

The operation of the radial hydraulic machine equipped with oscillating cylinders of an improved type occurs as usual with the oscillation of the cylinders 6, 34 or 44 on the annular spherical surfaces 13, 37 or 60. The contact, however, between the surfaces involved in the sliding, spherical annular 13, 37 or 60 and internal truncated conical annular 14 or 36 or also internal arcuate annular 61, compared to the known art, it is of a completely rigid and very limited type, due to a narrow band around the contact circumference of radius R2, i.e. in the median zone 42 of the internal annular surface 14, 36 or 61, due to the yield due to the elasticity of the materials used. The band therefore operates with contact pressures between the materials contained if the sizing of the surfaces has been carried out within the parameters mentioned above, even in the presence of high and variable axis hydraulic fluid pressure, as is known to happen for hydraulic machines with radial cylinders .

The proposed solutions for making contact between the spherical oscillation surface, made with spherical annular surfaces with radius R1 and diameter D1, allow to contain the thrust generated by the pressurized liquid in its evolutions in the radial oscillating cylinder if the radius R2 of the circumference of contact between it spherical annular surface with radius R1, diameter D1, and the internal truncated conical annular surface 13 or 37, or the inner arcuate annular surface 61 with radius of curvature R3, because the surface involved in generating the thrust S is limited to an annular band area, which is the difference between the bore area, diameter D, i.e. TT (D / 2) <2> subject to the pressure of the liquid, minus the area that is internal to said contact circumference a radius R2, i.e. TT (R2) <2> and which discharges the pressure of the liquid directly onto the body 10, 39 or 50 of the hydraulic machine, according to the invention, through the oscillation contact.

Therefore, the thrust S that will be transmitted between the two surfaces in contact due to the cylinder oscillation results as a function of S = P x (TT (D / 2) <2> -TT (R2) <2>) in which P is the instantaneous pressure that reigns inside the cylinder during operation.

Thus a construction with R2 = D / 2 leads to having a zero thrust effect of the liquid under pressure in the contact between the spherical oscillation surface and the contact surface in the bottom 15, 35 or 62. That is, the dimensioning of the surface radii spherical R1 and of the arched surface R3 or of the position and angle of semi-opening β truncated conical annular surface 14, allows to control the thrust S in the contact between them so as to limit its value within the limits tolerated by the material (s) used / i in the realization of the two surfaces in contact.

In operation, the presence of rings 22 for thrusting the oscillating cylinders 6 or 34 against the spherical oscillation surface ensures contact and sealing between the oscillation surfaces: spherical annular 13 or 37 and truncated conical annular 14 or 36, also starting or in the absence of pressure in the oscillating cylinder.

Finally, the reduction of the overall dimensions, possible due to the concentration in the interior of the circumference with radius R2, and reduction of the amplitude of the spherical annular contact surface between the oscillating cylinder and the body or shell of the radial cylinder hydraulic machine, leads to larger sections of the channels for supplying or discharging the hydraulic liquid to and from the hydraulic rocking cylinder described in the present invention. This effect is very evident if applied to the feeding of the oscillating cylinder on the side of the cylinder itself, so as to limit the radial dimensions typical of hydraulic machines with oscillating radial cylinders known in the art.

The advantages in the construction and use of a hydraulic machine, with improved radial cylinders described above, are expressed by a simple construction, for the realization of the oscillation surfaces of the cylinders, whether they are made in one piece on the casing of the machine body or brought back to the inside the mantle, by applying a mechanical member inserted with the spherical annular surface as described. The cylinder made according to the present invention will have a limited oscillation surface on the bottom, allowing to increase the passage sections of the hydraulic fluid: in fact, the passage section between the fixed part, the body of the hydraulic machine, and mobile because it oscillates, the cylinder, or skirt and cylinder, with the present invention the contact surface between the oscillating cylinder and the body or skirt of the hydraulic machine is reduced. This advantage is amplified if the feeding of the oscillating cylinder occurs in the area of the external lateral surface of the cylinder with less displacement due to the oscillation, as typically happens to the oscillating cylinders with tangs, but it has a considerable advantage, compared to the latter, given by the elimination of the encumbrance limit of the sizing of the supply channel inside the shank. Even more, the construction forms described are suitable for hydraulic motors, in Figure 1 made with fixed displacement, but the characteristics and advantages of the present invention can also be applied to hydraulic pumps with oscillating radial cylinders and, given the known techniques that make changes of the displacement in these hydraulic machines, motors and pumps, also with continuous variation of the displacement, so as to specifically benefit the oscillation surfaces, in the case of construction of variable displacement radial hydraulic motors, which are limited in the performance at reduced displacement by limited sections flow of the feed liquid and poor lubrication of the cylinder oscillation surface.

In conclusion, the most evident advantages are achieved by reducing the dimensions and increasing the passage sections in the channels and holes for feeding the hydraulic liquid, if also applied to known hydraulic machines, i.e. with feeding the oscillating cylinder from inside the spherical surface. of oscillation, but further and more significant advantages are obtained with the combination of the invention described above in hydraulic machines also equipped with the supply of hydraulic liquid on the side of the oscillating radial cylinder, as described above.

Obviously, a person skilled in the art, in order to satisfy specific and contingent needs, may make numerous modifications to the improved radial hydraulic machine described above, all of which however are contained within the scope of protection of the present invention as defined by the following claims.

Claims (10)

CLAIMS 1. Hydraulic machine with radial cylinders, comprising radial cylinders oscillating near the outer skirt of the crown or star of cylinder-piston groups; the pistons (3, 33, 45) of said groups are made to slide on a cranked (2) or eccentric crankshaft (1), or on interposed organs concentric thereto, and perform the reciprocating motion in the oscillating radial cylinders; characterized in this, which has said oscillating cylinders (6, 34, 44) placed in contact with a spherical surface of oscillation (13, 37, 60) made or inserted in the body (10, 39, 50) or shell of the hydraulic machine ; each oscillating radial cylinder being provided with an inner annular surface (14, 36, 61) with a curvature greater than the radius of the spherical oscillation surface, for coupling with said spherical oscillation surface to make a contact on a circumference having a width of the band due only to the elastic yielding of the materials in the area of the contact circumference; finally, there are means for pushing the oscillating cylinders against the spherical oscillation surface. Hydraulic machine according to claim 1, wherein the radius (R2) of the contact circumference is less than half the diameter (D) of the cylinder bore (6, 34, 44). Hydraulic machine according to one of claims 1 or 2, wherein the diameter (D1) of the spherical oscillating surface (13, 37, 60) is smaller than the bore diameter (D) of the radial oscillating cylinder (6, 34) , 44). 4. Hydraulic machine, according to one of claims 1, 2 or 3, in which the spherical oscillation surface (13, 37) has a limited annular conformation in the vicinity of the median contact area (42) around the circumference of contact with the surface inner annular (14, 36). 5. Hydraulic machine, according to claim 3, in which the spherical surface of oscillation (13, 37) has a limited annular conformation in the vicinity of a median contact area (42) around the circumference of contact with the internal annular surface constituted from an internal frusto-conical surface (14, 36) and said internal frusto-conical surface (14, 36) has a limited annular conformation in proximity to the median contact area (42) with the spherical oscillation surface. Hydraulic machine according to one of claims 1, 2 or 3, in which the spherical surface of oscillation (60) and an internal arcuate annular surface (61) both have an annular conformation limited to the narrow median contact area (42) in the around the circumference of contact therebetween the oscillation surface of the radial hydraulic cylinder; the radius (R3) of curvature of the internal arcuate annular surface being greater than the radius (R1) of the spherical surface of oscillation and less than the infinite value (°°). 7. Hydraulic machine, according to one of the preceding claims from 1 to 6, in which the supply and / or discharge of the hydraulic fluid in the oscillating cylinder takes place through one side of the cylinder itself. 8. Hydraulic machine, according to claim 7, in which the passage of the hydraulic liquid towards and from the oscillating radial cylinder (6), to supply and discharge the cylinder, through at least one external lateral surface (16, 20) on the side of the oscillating cylinder to and from a feed channel (26) on the body (10) or lateral cover (11) of the hydraulic machine (5); a sealing ring (23), equipped at least with a contact surface resistant to abrasion on the surface of the sliding wall (20, 21), is interposed between the side surfaces (16-20, 17-21) in contact for the passage of the liquid under supply pressure. 9. Hydraulic machine, according to claim 8, in which in an external lateral surface (17), parallel and opposite to the external lateral surface (16) to the oscillating cylinder (6) crossed by the liquid supply, there is a compensation hole (19) of the thrusts, fed by the liquid under pressure in the oscillating cylinder, around which a sealing ring (23) is placed between the lateral surfaces in contact (17-21) for the passage of the liquid under pressure through the compensation hole . 10. Hydraulic machine, according to one of the preceding claims 1 to 6, in which said thrust means on the oscillating radial cylinder (6, 34), for contact with the spherical oscillation surface, are constituted on both external sides of the cylinder oscillating with an arched step (24), with a curvature corresponding to the spherical oscillation surface (13, 37) of the cylinder, which engage in corresponding arched abutments (25) made on a ring (22), for each side of the cylinder units. piston, with the aim of maintaining contact between the spherical surfaces of oscillation and the internal annular surface (14, 36, 61) of the bottom (15, 35, 62) of the oscillating cylinder, at start-up and in the absence of liquid pressure in the cylinder .