EP2510192B1 - Hydrostatic radial piston machine - Google Patents

Description

• einem Gehäuse,
• einem um eine Drehachse drehbar in dem Gehäuse gelagerten Zylinderstern, der eine Anzahl von Bohrungen besitzt, die sich ausgehend von einer äußeren Mantelfläche des Zylindersterns in dessen Inneres hinein erstrecken und über dessen Umfang verteilt angeordnet sind,
• einer der Anzahl der Bohrungen entsprechenden Anzahl von Kolben, die in den Bohrungen verschiebbar angeordnet sind und jeweils zusammen mit der zugeordneten Bohrung einen Arbeitsraum für ein Hydraulikfluid begrenzen,
• einem exzentrisch zu dem Zylinderstern angeordneten Hubring, der den Zylinderstern umlaufend umgibt und an dessen innerer Mantelfläche sich dem Zylinderstern abgewandte Enden der Kolben während der Drehbewegung des Zylindersterns beweglich abstützen,
• zwei Steuerspiegelkörpern, die insgesamt mindestes zwei Steuerquerschnitte aufweisen, von denen mindestens einer mit dem Einlasskanal und mindestens ein anderer mit dem Auslasskanal in Verbindung steht, wobei beide Steuerspiegelkörper sich jeweils mit einer dem Zylinderstern zugewandten Stirnfläche auf eine zu der Drehachse senkrechte Mittelebene des Zylindersterns zu über eine Ebene hinaus erstrecken, die von einer dem jeweiligen Steuerspiegelkörper zugewandten Stirnfläche des Zylindersterns an dessen Stelle mit der größten axialen Breite definiert ist,
• einer der Anzahl der Bohrungen des Zylindersterns entsprechenden Anzahl von in letzterem angeordnetem Durchlasskanälen, die - je nach Drehstellung des Zylindersterns in dem Hubring - jeweils einen Arbeitsraum mit einem mit dem Einlasskanal korrespondierenden Steuerquerschnitt oder mit einem mit dem Auslasskanal korrespondierenden Steuerquerschnitt verbinden oder von einer an dem Steuerspiegelkörper befindlichen Verschlussfläche verschließbar sind.

The invention relates to a hydrostatic radial piston machine with

• a housing,
• a cylinder star rotatably mounted in the housing about a rotation axis and having a number of bores which extend from an outer surface of the cylinder star into its interior and are distributed over its circumference,
• one of the number of holes corresponding number of pistons which are slidably disposed in the bores and each defining a working space for a hydraulic fluid together with the associated bore,
• an eccentrically arranged to the cylinder star cam ring, which surrounds the cylinder star circumferentially and on the inner circumferential surface of the cylinder star facing away from the ends of the piston during the rotational movement of the cylinder star movably supported,
• two control mirror bodies which have a total of at least two control cross sections, at least one of which is in communication with the inlet channel and at least one other with the outlet channel, wherein both control mirror body each with a cylinder star facing end face to a perpendicular to the axis of rotation center plane of the cylinder star over extending beyond a plane which is defined by an end face of the cylinder star facing the respective control body in its place with the greatest axial width,
• one of the number of holes in the cylinder star corresponding number arranged in the latter passage channels, which - depending on the rotational position of the cylinder star in the cam ring - each have a working space with a corresponding with the inlet channel control cross-section or one with the outlet channel connect corresponding control cross-section or can be closed by a located on the control mirror body closure surface.

State of the art

Radial piston machines, ie radial piston pumps and radial piston motors, can be subdivided among other things according to how the hydraulic fluid is supplied to the work spaces in the cylinder star. From the EP-A-0 401 408 It is known that the supply and discharge of the hydraulic fluid via a stationary, ie connected to the housing so-called control pin. Disadvantages of this very widespread design are that only relatively narrow flow channels (inlet and outlet channel) can be realized within the control pin and that due to the axially out of the control pin flow channels, the mechanical bending load of the control pin is quite high. As an advantage of this known construction can be stated that the bearing of a drive or output shaft is hardly loaded. However, the fit between the outer surface of the control pin and the inner surface of the rotating cylinder star causes problems. There is by design no zero gap possible, the leakage increases in the third power with the running play, resulting in larger leakage rates in particular with progressive wear. In addition, the previously known principle of the control pin-cylinder star fit is sensitive to dirt particles contaminated hydraulic fluids and temperature jumps.

An alternative principle of the supply / removal of the hydraulic fluid to / from the cylinder star is from the documents DE-A-1 812 635 . DE-A-24 52 092 . DE-A-41 23 674 and DE-A-41 23 675 known. In the construction disclosed in these documents is the control mirror body, which may also be integral with the housing, axially adjacent to the cylinder star. As a problem in this design, the large forces acting in the axial direction and their permanent wear-resistant support to be considered. In addition, the radial reaction forces from the hydraulic pressure on the shaft and must be absorbed by the shaft bearing.

A radial piston engine of the type described above and with the features of the preamble of claim 1 is for example from the US-A-3,951,044 known. The disclosed therein machine has two arranged on opposite sides of the cylinder star control mirror body, which have on the side facing the cylinder star a spherical shape, which cooperates with an analogous dome-shaped shape of the opposite side surfaces of the cylinder star (s. especially the local ones FIG. 4 ). In order to avoid jamming and friction between the control mirror bodies and the cylinder star during operation of the machine, in the known machine at least one control mirror body is limited in all directions, ie both in the axial and in the radial direction, movable. As a result, the rotating shaft connected to the cylinder spider must absorb the radial forces arising during operation due to the hydraulic pressures. This in turn leads to increased construction costs for the shaft and its storage and to potential wear.

The same principle, possible misalignment in the fit between the cylinder star and the or the control mirror body (s) by the possibility of a radial displacement of at least one control mirror body to avoid, is also the machine according to the DE-A-1 776 238 as well as the US-A-3,122,104 based. In the no eccentrically arranged but an elliptically shaped cam having double-stroke machine (two piston strokes per revolution) according to the US-A-3,122,104 This results in no problem due to the symmetry and the mutually canceling radial forces. In single-stroke machines with extrentric cam ring, however, the known principle leads to considerable friction and great demands on the shaft bearing. For this reason, the solutions according to the three above-mentioned earlier documents have found no input in practice.

task

The invention has for its object to propose a radial piston engine, in which the hydraulic forces can be fully hydrostatically relieved and stably supported.

solution

Based on a radial piston machine of the type described above, the underlying object is achieved in that each control mirror body has a bearing region in which radially acting forces on a respective mating surface in the housing or a housing cover mounted therein are transferable.

In the context of the present invention, a control-plate body can be understood as meaning either a separate component in comparison with the housing, or a design integrally connected to the housing or a housing cover. A control mirror body must not be traversed by the hydraulic fluid, which may be the case when in a single control mirror body both control cross sections, ie both for the supply and the discharge of the hydraulic fluid from the cylinder chambers, whereas the other control mirror body no function in relation to the fluid supply of the cylinder star is met. The term control mirror body is therefore geometrically and mechanically understood in the present sense and not necessarily in relation to a flow of hydraulic fluid. Decisive is an abutment with the cylinder star in the axial direction.

According to the invention is - viewed in the axial direction - not only an intervention of the two control mirror body in the cylinder star before, but also a derivative of the radial forces on the control mirror body. In an axial section of the two aforementioned components, these thus overlap, wherein the control mirror body protrude in a radially further inner region in the direction of the axial center of the cylinder star, whereby a radially further outward region of the cylinder star covers the two control mirror body quasi. Due to the inventive storage of the control mirror body is a complete hydrostatic discharge of the hydraulic forces occurring during operation and a stable support thereof via the housing or the housing cover, possible. Due to the symmetrical arrangement of the two control mirror body with respect to a central plane of the cylinder star, the hydraulic forces acting in the radial direction in the areas of the opposing control mirror body, in which they protrude into the cylinder star, initially by obliquely to the axis of rotation extending and opposite forces intercept. Each control disk body extending into the cylinder star thus fulfills - figuratively speaking and in an axial section view - the function of a "collar" known from architecture, whereas in each case the area of the cylinder star in which the width increases - when viewed radially outwards acts as a kind of "capstone" that converts radial compressive forces into a pair of oppositely biased forces, the radial components of which are in turn derived respectively from the opposed control disc bodies into the housing or housing cover which supports them.

In contrast, the control mirror body at radially extending separation level in the control cross sections, ie in the region of the interface between the control mirror body and cylinder star, disc-shaped and have only perpendicular to the axis of rotation extending end faces. Due to this design, a support during operation occurring radial forces on the control mirror body is impossible. The same applies to spherical ones or conical / conical control mirror body, but can not transmit any radial forces on the housing or its cover for lack of appropriate storage. Here, the invention provides by the interengagement of cylinder star and control plate body and their storage in the housing or housing cover, remedy, resulting in a particularly high compressive strength of the radial piston engine according to the invention. Another advantage of the invention, the great robustness of the machine is to look at pressure surges and vibrations, as a closed power flow involving the typically very rigid machine housing, which in turn results in a low noise emission. Due to the complete hydrostatic discharge of the hydraulic forces, the machine according to the invention is also suitable for poorly lubricating media, ie in particular for use in the so-called "water hydraulics".

Preferably, the cylinder star has at least one support region in which the axial width is smaller than in a free-wheeling region which adjoins the support region in the radial direction, wherein at least one control cross-section of the control-plate body is preferably located in the support region. Further preferably, at least one control plate body has a support region corresponding to the support region of the cylinder star and a storage region facing away from the support region in the radial direction outwardly adjoining the support region and / or in the axial direction. In the storage area, the respective control plate body is accommodated in a housing or housing cover, so that the forces introduced by the cylinder star into the control plate body can be dissipated further into the housing or the housing cover.

A particularly robust mechanical construction of the radial piston machine according to the invention is achieved if the support region preferably extends from a central torque coupling region (eg in the form of a multi-tooth bore or a journal) in the radial direction up to a diameter which is approximately 60%. to 90%, preferably 70% to 80%, of the maximum diameter of the cylinder star.

A particularly favorable geometry of the control plate body is present if this has a conical, conical-ring-shaped or convex, in particular spherical, curved shape, wherein preferably the support region is designed conical, conical-shaped or convex, in particular spherical, arched. The adjoining in the axial direction storage area, which may have a larger diameter than the support area, then preferably a cylindrical shape, resulting in a particularly simple storage in the housing or the housing cover.

In conical or conical annular control mirror body, the cone angle should be between 90 ° and 150 °, preferably between 110 ° and 130 ° and more preferably 120 °, since this is an equiangular triangle of forces with an angle between the radially acting pressure force and the obliquely directed supporting forces of each 120 ° results. The optimum cone angle in each case results from the respective diameters at the beginning and at the end of the conical section and the number of working spaces distributed over the circumference of the cylinder star and can be computationally exact according to the known rules of hydraulics under the premise of a complete hydraulic balance of forces determine.

The invention further ausgestaltend it is proposed that the cylinder star and at least one control mirror body in the axial direction patrizen-matrizen-shaped mesh.

If a respective control mirror body is arranged on both sides of the cylinder star, one of them should be biased in the direction of the opposite control mirror body by means of a spring element supported on a housing or a housing cover, preferably a corrugated spring. This provides axial gap compensation, i. Tightness, in the region of the separation plane between the control mirror body and the cylinder star, in particular in the area of the control cross sections achieved.

Regardless of whether the supply or discharge of the hydraulic fluid to or from the cylinder star via only one or two control mirror body, it makes sense from a manufacturing point of view, that control channels of two opposing control mirror body and an interposed passageway of the cylinder star are aligned, preferably form a continuous cylindrical bore with a constant cross section. Under the aspect of an always desirable equal part production, the control channels are unused in a control disk body which is not used for hydraulic fluid supply or exhaust, but this is in no way disadvantageous.

Although it is basically possible to provide the pistons on the piston heads with a separate sealing element (piston ring or the like), it is a preferred variant that each piston head of the piston is designed cup-shaped in longitudinal section and with no interposition of a separate sealing element a cup rim sealing at an inner Mantle surface of the respective bore of the cylinder star rests, wherein the pistons are preferably made of plastic and more preferably are plastic injection molded parts. The cup rim has a depth seen in the axial direction of the piston and a thickness seen in the radial direction, which ensures that the fluid pressure in the working space, taking advantage of the component elasticity, ensures sufficient surface pressure between the cup rim outer casing and the bore casing surface. In a production of such pistons as plastic injection molded parts made of a material with sufficient strength, low coefficient of friction in conjunction with the material of the cylinder star and at the same time good elasticity, the pistons according to the invention can be produced very inexpensively.

embodiment

The invention will be explained in more detail with reference to two embodiments of a hydrostatic radial piston machine, which is shown in the drawing.

Fig. 1:

Einen Querschnitt durch eine erste Ausführungsform einer Radialkolbenmaschine mit Kolben mit Kolbenringen,

Fig. 2:

wie Figur 1, jedoch im Längsschnitt,

Fig. 2a:

eine vergrößerte Ansicht des Zylindersterns und der Steuerspiegelkörper gemäß Figur 2,

Fig. 3:

einen Querschnitt durch eine zweite Ausführungsform einer Radialkolbenmaschine mit Kolben in Becherform,

Fig. 4:

wie Figur 3, jedoch im Längsschnitt und

Fig. 5:

wie Figur 1, jedoch mit durch Pfeile veranschaulichten Kraftvektoren

It shows:

Fig. 1:

A cross section through a first embodiment of a radial piston machine with piston with piston rings,

Fig. 2:

as FIG. 1 but in longitudinal section,

Fig. 2a:

an enlarged view of the cylinder star and the control mirror body according to FIG. 2 .

3:

a cross section through a second embodiment of a radial piston machine with piston in cup shape,

4:

as FIG. 3 , but in longitudinal section and

Fig. 5:

as FIG. 1 but with force vectors illustrated by arrows

One in the FIGS. 1 . 2 and 2a illustrated radial piston machine 1 comprises a housing 2, which - viewed in the axial direction - is closed fluid-tight on one side with a housing cover 3. In the housing 2, a cam ring 4 is slidably mounted and along each two planar surfaces 5 and 6, which are formed on the one hand on an inner circumferential surface 7 of the housing 2 and on the other hand on an outer circumferential surface 8 of the cam ring.

In addition, the radial piston machine 1 has a rotor in the form of a so-called cylinder star 9, which is rotatable about a rotation axis 10. The cylinder star 9 has in this case nine equidistantly distributed over its circumference arranged holes 11, which, starting from an outer circumferential surface 12 of the cylinder star 9 radially into its interior, i. on the axis of rotation 10 to extend.

In each bore 11, a piston 13 is slidably disposed, each piston 13 has a piston head 14, with which it is sealed in the bore 11 is mounted, and a plate-shaped piston foot 15, with the lower end face 16 of the respective piston 13 at a spherical curved inner lateral surface 17 of the cam ring 4 is supported. Each piston 13 has a from the piston head 14 to the piston 15 extending through bore 18 which opens at the end face 16 of the piston 15 in a pressure chamber 19, which in turn leads to a hydrostatic relief of the bearing of the piston 15 on the lifting ring 4. In known manner, each piston 13 has in the region of its piston head 14 a circumferential groove into which a piston ring 20 is inserted for sealing purposes. Between the piston head 14 and the piston 15 there is a reduced diameter piston neck, which - depending on the position of the piston 13 in the bore 11 - allows tilting of the piston longitudinal axis to the bore longitudinal axis.

According to the known basic principle of radial piston machines, the axis of rotation 10 of the cylinder star 9 and the center axis of the cam ring 4 (the center axis of the cam ring is not shown in the drawing for reasons of clarity) are arranged eccentrically to each other, wherein the (variable) amount of eccentricity the stroke of Piston 13 defined. During a complete rotation of the cylinder star 9 about the axis of rotation 10, the pistons 13 therefore move from a top dead center, where they are immersed in the deepest hole 11, to a bottom dead center, where they together with the walls of the bore 11 a then limit maximum working space 22. The extent of eccentricity between the cylinder star 9 and cam 4 can be varied in the present case with the aid of two hydraulic adjusting cylinders, the cylinder bores 23 and 24 are located on opposite sides of the housing 2 and each with an axially in the cylinder bore 23, 24 slidably mounted cup-shaped Pistons 25, 26 are provided. Starting from the in FIG. 1 shown position in which the eccentricity is maximum leaves the cam 4 (parallel to the flat surfaces 5 and 6) to move the way to the right 27, whereby the eccentricity and thus the delivery rate of the radial piston machine is reduced to zero.

In likewise known from the prior art, the promotion of hydraulic fluid using the radial piston engine - exemplified by a function as a radial piston pump - in such a way that hydraulic fluid from one located in the housing 2 and at its radially inner end by 90 ° angled inlet channel 28 flows into a control channel 29 of a control mirror body 30. The control mirror body 30 is located between a housing wall 31 and the cylinder star 9. Another, substantially identical shaped control mirror body 32 is located on the opposite side of the cylinder star 9 and is bounded on its side facing away from the cylinder star 9 by a housing wall 33. In both control mirror bodies 30, 32, the respective control channel 29, 34 in a cylinder star 9 facing end face of the control mirror body 30, 32 extends in a circular segment. This known design makes it possible for the hydraulic fluid to flow from the control channel 29 into the respective working space 22 via a respective passageway 35 assigned to each bore 11 in the cylinder star 9 during a suction phase extending over an angular range of approximately 150 °. As soon as a piston 13 has reached its bottom dead center, the flow connection between the control channel 29 assigned to the inlet channel 28 and the associated passage channel 35 ends, whereas at the next moment a connection exists between the further control channel 37 constructed like the control channel 29 and an outlet channel 36 the "pressure side" of the control mirror body 30 and the radial piston machine 1 is produced. The cross sections of the control channels 29, 37, which are arranged in the respective separation planes between the control mirror body 30 and the cylinder star 9 are referred to as control cross sections 29 ', 37'.

As a result of a continuous rotation of the cylinder star 9, each piston 13 pushes the hydraulic fluid in the associated working space 22 through the passage channel 35 associated with each bore 11 and the control channel 37 extending over a circular segment of approximately 150 ° into the outlet channel 36. Between the control cross sections 29 ', 37' of the control mirror body 30 are two 180 ° offset from each other closure surfaces (not visible in the figures), the passageways 35 each in two intermediate areas between the control cross sections 29 'and 37' close to a short circuit between To prevent suction and pressure side. The in FIG. 2 Control plate body 32 shown on the right also has a second, ie lower, control channel 38, which in the present case - as well as the upper control channel 34 of this control mirror body 32 - is inoperative.

In order to be able to reliably convey large volume flows from the hydraulic fluid on the suction side of the radial piston machine 1, if necessary, the suction-side control channel 34 of the control plate body 32 can likewise be connected to the inlet channel 28. On the pressure side, the connection of the control channel 38 with the outlet channel 36 is hardly required; For the sake of the same part production, however, both control mirror body 30, 32 are each provided with two control channels 29, 37 and 34, 38.

In order to achieve an axial gap compensation in the region of the control plate body 30, 32 and the cylinder star 9, is located between the housing wall 33 and this facing end face of the control mirror body 32 is only schematically illustrated spring element 39 in the form of a rotating wave spring. However, the spring element 39 is not able to apply such large forces to compensate for the high hydraulic forces acting in the axial direction. For this purpose, a pressure-compensated compensation surface K is additively provided on the end face of the cover 3 facing the control mirror body 32. This compensation surface K is twice kidney-shaped and corresponds on the one hand with the suction-side control channel 29 and the other with the pressure-side control channel 37. By means of a likewise kidney-shaped sealing member D is a corresponding with the compensation surface K volume between the housing cover 3 and the rear side facing this End face of the control mirror body 32 sealed. In this way, a pressure-proportional axial contact force is generated, which is always only a few percent above the axial component of the hydraulic splitting force on the respective control mirror body 30, 32. Thus, the gap compensation is ensured without generating large "excess forces", which would only lead to increased friction.

Based on the enlarged view according to FIG. 2a Now special features of the control mirror body 30, 32 and the cylinder star 9 are explained:

Both Steuerspiegelköper 30, 32 each have a conical-ring-shaped support portion 40, 41 which cooperates with a complementarily shaped, also cone-shaped support portion 42, 43 on the opposite end faces of the cylinder star 9. While in the support areas 40, 41 of the control mirror body 30, 32, the control channels 29, 37 and 34, 38, ie in particular also the control cross sections 29 ', 37', which are as through holes executed passageways 35 in the mutual support areas 42 and 43 of the cylinder star. 9

Both control mirror bodies 30, 32 each have a central through-bore 44, 45 through which runs a drive shaft 46 of the radial piston machine 1. A torque I <oppelbereich 47 of the cylinder star 9 is designed as a hexagon socket, in which a suitably adapted external hexagon of the drive shaft 46 is inserted in a rotationally fixed manner.

Both control plate bodies 30, 32 have a cylindrical-ring-shaped bearing region 48, 49 adjoining the respective support region 40, 41 in the radial direction, the outer lateral surface 50, 51 of which is respectively mounted in a matched recess in the housing 2 or the housing cover 3 is. The cylinder star 9 has a - viewed in the radial direction - at the support areas 42 and 43 subsequent freewheeling 52, 53, in which between the respective end face 54, 55 of the cylinder star 9 and the opposite end face 56, 57 of the control mirror body 30, 32nd in each case a gap 58, 59 is located.

Out FIG. 2a It can be seen that the measured in the axial direction width of the cylinder star 9 in the support areas 42, 43 to the rotation axis 10 decreases. The largest axial width 60 is in the freewheeling region 52, 53, whereas the smallest axial width 61 is in the torque coupling region 47. The cone angle of the control plate body 30, 32 is 120 °, so that the track straight of the drawing section plane with the control mirror bodies 30, 32 with the axis of rotation 10 each enclose an angle of 60 °.

Furthermore, it can be seen that the control mirror bodies 30, 32 with their conical-ring-shaped end faces forming the support regions 42, 43 extend beyond the planes formed by the end faces 54, 55 of the cylinder star 9 in the direction of a center plane 62 of the cylinder star perpendicular to the rotation axis 10 9 extend.

The difference in the FIGS. 3 and 4 shown radial piston machine 1 is that the piston 13 'there have a cup-shaped shape in longitudinal section. A in the respective piston head 14 'arranged cup edge 63 has a small, towards the free end of the cup rim 63 towards decreasing wall thickness, so that as a result of a pressure build-up in the working chamber 22 of the respective bore 11 in the cylinder star 9 a self-reinforcing Sealing effect occurs. The pistons 13 'are made as plastic injection molded parts and consist for example of PEEK (poly ether ether ketone) or PAI (poly amide imide).

The piston 13 'are rotationally symmetrical components, wherein the plastic material used elastically in its contact area with the inner circumferential surface of the bore 11 allows a change in shape, as a result of the inclination of the piston 13' during rotation of the cylinder star 9, the contact line in the area the piston head 14 'describes an ellipse.

In the cross-sectional view according to FIG. 5 Finally, the various force vectors occurring during operation of the radial piston machine 1 are also illustrated: The radial hydraulic forces acting in the respective working chamber 22, illustrated by the arrow P1, are hydraulically compensated by the symmetrically inclined end faces of the cylinder star 9 or the control mirror bodies 30, 32 , which is illustrated by the hydraulic force vectors according to the arrows P2 and P3. In addition, in FIG. 5 nor the mechanical forces shown in the arrows P4, the reaction forces occurring in the housing 2 to the hydraulic forces, which are transmitted from the working chamber 22 via the piston 26 and the cam 4. The forces acting on the control mirror bodies 30, 32 in the radial direction are transmitted in their bearing areas 48, 49 to the respective mating surface in the housing 2 or housing cover 3, where the reaction forces are shown in the form of the arrows P5. <B> LIST OF REFERENCES </ b> 1 Radial piston engine 2 casing 3 housing cover 4 lifting ring 5 plane surface 6 plane surface 7 inner jacket surface 8th outer jacket surface 9 cylinder radial 10 axis of rotation 11 drilling 12 outer jacket surface 13, 13 ' piston 14, 14 ' piston head 15 piston base 16 face 17 inner jacket surface 18 Through Hole 19 pressure chamber 20 piston ring 21 tang 22 working space 23 bore 24 bore 25 piston 26 piston 27 path 28 inlet channel 29 control channel 29 ' Control section 30 Control mirror body 31 housing wall 32 Control mirror body 33 housing wall 34 control channel 35 Passageway 36 exhaust port 37 control channel 37 ' Control section 38 control channel 39 spring element 40 support area 41 support area 42 support area 43 support area 44 Through Hole 45 Through Hole 46 drive shaft 47 Torque coupling region 48 storage area 49 storage area 50 outer jacket surface 51 outer jacket surface 52 Freewheel area 53 Freewheel area 54 face 55 face 56 face 57 face 58 gap 59 gap 60 width 61 width 62 midplane 63 cup edge D sealing element K compensation area P1 arrow P2 arrow P3 arrow P4 arrow P5 arrow

Claims (11)

1. A hydrostatic radial piston machine (1) having

   - a housing,

   - a cylinder star (9) which mounted in the housing (2) such that it can rotate about a rotation axis (10) and has a number of bores (11) which extend starting from an outer lateral surface (12) of the cylinder star (9) into the interior thereof and are distributed over the circumference thereof,

   - a number of pistons (13, 13') corresponding to the number of bores (11), which are arranged in a displaceable manner in the bores (11) and each delimit a working space (22) for a hydraulic fluid together with the associated bore (11),

   - a lifting ring (4), which is arranged eccentrically to the cylinder star (9) and surrounds the cylinder star (9) in a circumferential manner, and on the inner lateral surface (17) of which ends of the pistons (13, 13') which face away from the cylinder star (9) are supported in a movable manner during the rotary movement of the cylinder star (9),

   - two control mirror bodies (30, 32), which have at least two control cross sections in total, of which at least one is connected to the inlet duct (28) and at least one other is connected to the outlet duct (36), wherein both control mirror bodies (30, 32) each extend with an end face facing the cylinder star (9) towards a central plane (62) of the cylinder star (9), which plane is perpendicular to the rotation axis (10), beyond a plane which is defined by an end face (54, 55) of the cylinder star (9) facing the respective control mirror body (30, 32) at the point of the cylinder star with the greatest axial width (60),

   - a number, which corresponds to the number of bores (11) in the cylinder star (9), of through-ducts (35) which are arranged in the latter and - depending on the rotation position of the cylinder star (9) in the lifting ring (4) - each connect a working space (22) to a control cross section which corresponds to the inlet duct (28) or to a control cross section which corresponds to the outlet duct (36) or can be closed by a closure face which is situated on the control mirror body (30, 32),

   characterised in that each control mirror body (30, 32) has a bearing region (48, 49) in which radially effective forces can be transmitted to a respective counter face in the housing (2) or a housing cover (3) mounted therein.
2. The radial piston machine according to Claim 1, characterised in that the cylinder star (9) has at least one supporting region (42, 43), in which the axial width is smaller than in a free-running region (52) which is joined to the supporting region (42, 43) to the outside in the radial direction, wherein preferably at least one control cross section of the control mirror body (30, 32) is situated in the supporting region (42, 43), wherein further preferably at least one control mirror body (30, 32) has a supporting region (40, 41) which corresponds to the supporting region (42, 43) of the cylinder star (9), wherein preferably the respective bearing region (48, 49) is joined to the supporting region (40, 41) either towards the outside in the radial direction and/or in the axial direction facing away from the supporting region (40, 41).
3. The radial piston machine according to Claim 2, characterised in that the supporting region (42, 43) of the cylinder star (9) preferably extends starting from a central torque-coupling region (47) in the radial direction to a diameter which is approximately 60% to 90%, preferably 70% to 80% of the maximum diameter of the cylinder star (9).
4. The radial piston machine according to one of Claims 1 to 3, characterised in that the control mirror body (30, 32) has a conical, conical-ring-shaped or convexly, in particular spherically curved shape, wherein preferably the supporting region (40, 41) is shaped in a conical, conical-ring-shaped or convexly, in particular spherically, curved manner.
5. The radial piston machine according to Claim 4, characterised in that the cone angle is between 90° and 150°, preferably between 110° and 130°.
6. The radial piston machine according to one of Claims 1 to 5, characterised in that the cylinder star (9) and at least one control mirror body (30, 32) interlock in a male/female manner in the axial direction.
7. The radial piston machine according to one of Claims 1 to 6, characterised in that the two control mirror bodies (30, 32) can be displaced in the axial direction relative to each other, preferably that one of the control mirror bodies (32) can be displaced in the axial direction relative to the housing (2) or the housing cover (3), whereas the other control mirror body (30) is fixed in the axial direction in the housing (2) or the housing cover (3).
8. The radial piston machine according to one of Claims 1 to 7, characterised in that in each case one control mirror body (30, 32) is arranged on both sides of the cylinder star (9), wherein one control mirror body (32) is prestressed in the direction of the opposite control mirror body (30) by means of a spring element (39), preferably a wave spring, which is supported on the housing (2) or housing cover (3).
9. The radial piston machine according to one of Claims 1 to 8, characterised in that through-ducts (35) of the cylinder star (9) which each correspond to a working space (22) each extend from one supporting region to the opposite supporting region (42, 43).
10. The radial piston machine according to one of Claims 1 to 9, characterised in that control ducts (29, 34, 37, 38) of two opposite control mirror bodies (30, 32) and a through-duct (35) of the cylinder star (9) arranged between them align with each other, preferably forming a continuous cylindrical bore with a constant cross section.
11. The radial piston machine according to one of Claims 1 to 10, characterised in that in each case a piston head (14') of the pistons (13') is cup-shaped in longitudinal section and bears with a cup edge (63) against an inner lateral surface of the respective bore (11) of the cylinder star (9) without a separate seal element being interposed, wherein the pistons (13') preferably consist of plastic and further preferably are plastic injection-moulded parts.

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