DE102008006123A1 - Radial piston machine for use as multi-stroke radial piston motor, has adjusting device for adjusting relative position of commutator with respect to lifting ring in sense of phase shift - Google Patents

Abstract

The machine has a set of pistons (22) adjustably guided in a rotatably supported cylinder star (18) in a radial direction, where each piston lies at a lifting ring (6) and defines a working chamber (26) with the cylinder star. The chamber and the lifting ring are connected with a pressurizing medium inlet (P) or a pressurizing medium outlet (T) over a set of control channels (42, 44) in a commutator (30). An adjusting device (56) adjusts a relative position of the commutator with respect to the lifting ring in the sense of a phase shift.

Description

The The invention relates to a variable displacement radial piston machine Delivery or absorption volume according to the Preamble of claim 1.

Such radial piston machines are designed as Mehrhubradialkolbenmaschine, wherein a plurality of pistons are guided displaceably in a radially mounted cylinder star in the radial direction. From the cylinder star in the radial direction outstanding end portions of the piston are on piston shoes on an inner peripheral surface of a cam ring, which is designed with control cam, so that in a relative rotation between the cylinder star and the fixed cam ring, the pistons are moved in the radial direction, so that the cylinder star and the Piston limited work spaces are cyclically increased or decreased. The work spaces are cyclically connected according to the piston position with a pressure medium inlet or a pressure fluid outlet, wherein in a front-side control disc corresponding control openings and control channels are formed to connect the respective working space with the pressure medium inlet or the pressure fluid outlet. The basic structure of such a radial piston machine is from the DE 198 32 196 A1 known.

adversely At this solution is that the delivery or swallow volume the work machine is not adjustable.

In the DE 36 37 174 A1 is a radial piston machine described in the workrooms for changing the delivery / absorption volume connected via a directional control valve and shut off from the pressure medium inlet and the pressure fluid outlet, so that these work spaces are virtually "off" and accordingly the delivery / displacement is reduced. An appropriate solution is also in the US 4,724,742 shown.

adversely with these solutions is that change the delivery / absorption volume only stepped with comparatively large volume differences can take place, so that an exact adaptation to the pressure medium requirement is not possible is. Another disadvantage is that the directional control valve with the required pressure medium channels in the hydraulic machine must be integrated, so that a considerable technical device Effort is required to one of the kind of gradual switching of the To realize delivery / absorption volume. Furthermore, can when switching the directional valve to pressure peaks come to the Damage to the components or lead to a noise emission.

In the textbook "Fundamentals of hydraulics"; Horst-W. Grollius; Fachbuchverlag Leipzig; 3. updated edition; 2006 " a radial piston machine is shown in which the cam ring is designed with a cylindrical control surface and the piston movement is effected by an eccentric arrangement of the cam ring with respect to the cylinder star. In such a solution, the delivery / displacement can be adjusted by adjusting the eccentricity between the cam and cylinder star.

the opposite the invention is the object of a Radial piston machine of the type mentioned above, in which the delivery / displacement volume can be changed in a simple manner is.

These Task is accomplished by a radial piston machine with the characteristics of the Patent claim 1 solved.

Has according to the invention the radial piston engine a plurality of in a rotatably mounted cylinder star slidably guided pistons against a stationary Hubring are biased and each with the cylinder chamber a Limit working space. The working spaces of the radial piston machine are via control channels formed in a commutator connectable to a pressure medium inlet and / or pressure fluid outlet. According to the invention, the relative position of the commutator over an adjusting device in terms of a phase shift with respect be adjusted to the lifting ring, so that - depending on the direction of rotation and rotation angle - a phase control, a phase section control or a phase separation control is enabled. Thereby can, for example, by compared to conventional Solutions late or earlier opening a pressure medium connection between the working space and low pressure the intake / discharge volume changed continuously so that even with conventional solutions occurring pulsations of the delivery or suction volume flow avoided or at least reduced.

at a variant of the invention according to the invention the commutator is rotatably mounted, allowing it to adjust the phase shift is pivoted by a predetermined angle of rotation can be.

The Adjustment of the commutator via a suitable Actuator, for example, a piezo actuator, a hydraulic or pneumatic actuator or an electromagnetic actuator, which is relatively easy in a housing of the radial piston machine integrate.

In a preferred embodiment the invention cylinder star and cam ring are arranged centrally. In principle, a variant with adjustable commutator could also be provided in a solution with eccentrically arranged lifting ring.

at A preferred embodiment is the radial piston machine designed as a multi-stroke radial piston engine.

other advantageous developments of the invention are the subject of further Dependent claims.

in the Below is a preferred embodiment of Invention explained in more detail with reference to schematic drawings. Show it:

1 a longitudinal section through a radial piston motor and

2 a radial section through the radial piston motor 1 ,

The basic structure of in 1 illustrated embodiment is in the DE 198 32 696 A1 described in detail, so that only the essential details for understanding the invention are explained and reference is made to the cited prior art.

The invention is based on a in the 1 and 2 illustrated radial piston motor, as mentioned, however, the radial piston machine can also be designed accordingly as a pump.

According to the in 1 shown longitudinal section along the section line II in 2 and in 2 illustrated section along the section line II-II in 1 has the radial piston engine 1 a two-part housing with two housing pots 2 . 4 between which a lifting ring 6 is arranged sealingly. In the case 2 . 4 is an output shaft 8th via a rolling bearing arrangement 10 . 12 stored, which can absorb both axial and radial forces. About the output shaft 8th For example, a wheel of a vehicle may be driven.

The output shaft 8th is with an external toothing 14 executed, with an internal toothing 16 a cylinder star 18 meshes, in which a plurality of in the outer circumference of the cylinder star 18 opening cylinder bores 20 are formed. In each of these is a piston 22 Slidably guided in the radial direction. According to the radial section in 2 are in the illustrated embodiment 8 pistons in the cylinder star 18 stored. In the longitudinal section according to 1 is the in 2 The piston below is not visible, because the cutting plane in the below the axis 24 lying area (see 2 ) is tilted and between two pistons 22 or cylinder bores 20 runs.

Every piston 22 and the associated cylinder bore 20 limit a workspace 26 , which is parallel to an axis 24 running channel 27 in an in 1 lying on the left end face 28 of the cylinder star 18 empties. D. h., In this face open a variety of each one of the work spaces 26 assigned channels 27 , about the pressure fluid in the work space 26 or from the work space 26 can flow. At the frontal area 28 of the rotatable cylinder star 18 is a control disk - hereinafter commutator 30 called - sealingly. This has an internal bore 32 and is in the illustrated embodiment with its stepped outer periphery rotatably mounted on a stepped bearing mount 34 of in 1 left housing pot 2 stored.

On the outer circumference of the commutator 30 are two circumferential grooves 38 . 40 , formed in each case together with the adjacent peripheral surface of the housing pot 2 an annulus 38 . 40 form, with the one annulus 38 about one in 1 Dashed indicated inlet port P to a system pressure leading line and the other annulus 40 Can be connected via a tank connection T to a tank or to low pressure. In the annulus 38 open a variety of inlet channels 42 , which are parallel to the axis 24 are formed and depending on the rotational position with the channel 27 a workroom 26 can be brought into overlap, so that then pressure medium the respective working space 26 can flow. That is, in the commutator 30 are a number of piston channels corresponding number of inlet channels 42 educated. Correspondingly are in the Kummutator 30 still a lot of in 1 indicated by dashed lines drainage channels 44 formed, on the one hand in the further annulus 40 and on the other hand depending on the rotational position with a channel 27 can be brought into overlap to pressure medium from the work space 26 remove to the tank.

As can be seen in particular from the illustration according to 2 gives, is an inner peripheral surface 46 of the cam ring 6 as a control or lifting cam with a variety of control cams 48 executed, wherein the number and geometry of the individual cams is selected so that in the illustrated embodiment in each case two pistons 22 are arranged at the outer and inner dead center, while the intervening pistons are in a corresponding staggered stroke position. Specifically, in the case of 2 illustrated embodiment, the eight pistons 22 six control cams 48 assigned. The pistons 22 are about roles 54 at the lift curve of the cam ring 6 supported.

In the illustration according to 2 are for better understanding of the mouth areas of the inlet channels 42 and the drainage channels 44 graphically offset radially outward and enlarged - as is apparent 1 result in concrete terms in the area of the canals 27 which, in the illustration according to 2 both at their concrete position (mouth in the working space 26 ) as well as in the relative position to the illustration drawn radially outward inlet and outlet channels 42 . 44 are shown. In this case, the mouth areas of the inlet channels 42 as feed control window 50 and the mouth areas of the drainage channels 44 as a flow control window 52 drawn, each having an approximately rectangular cross-section and lie on a common pitch circle. The likewise in 2 schematically marked mouth areas of the channels 27 are arranged approximately circularly, wherein the distance between two adjacent inlet and outlet control windows 50 . 52 is chosen so that the bridge remaining between two windows in the region of the inner and outer dead centers of the piston 22 the respective channel 27 covered, leaving the work space 26 is shut off both to the inlet port P and to the drain port T.

The other pistons 22 are accordingly in intermediate positions, in which either an inlet control window 50 or a flow control window 52 with the mouth area of a canal 27 covered. In the case where the inlet control window 50 to the canal 27 is open, can be pressurized system pressure via the pressure port P, the annulus 38 , the inlet channel 42 and the channel 27 into the relevant workspace 26 infuse, leaving the piston 22 is pressurized from the inside with high pressure and thus is forced radially outward. This force acts on the role 54 on the lifting ring 6 , so that according to the geometry of the lift curve, a torque on the cylinder star 18 is exercised and this in the direction of the arrow according to 2 is twisted, leaving the role 54 along the - clockwise direction 2 considered - in the radial direction outwardly sloping part of the respective cam 48 in 2 expires and the work space 26 is increased accordingly. When reaching the outer dead center, the channel 27 shut off and in another rotation, the pressure medium connection from the working space 26 to the flow control window 52 and thus to the drainage channel 44 piloted so that the pressure medium is depressurised from the working space 26 over the canal 27 , the drainage channel 44 , the annulus 40 and the tank port T can flow to the tank.

insofar The function of the radial piston engine does not differ from those of conventional solutions.

So far, the commutator 30 always rotatably received in the pump housing - as explained above, in the inventive solution, the commutator 30 rotatable in the housing pot 2 added. The rotational angle position of the commutator 30 with reference to the lift curve (cam 48 ) can by means of an actuator 56 be set, which at one on the outer circumference of the commutator 30 in the radial direction projecting driver 58 attacks. By actuating the actuator 56 can be the relative position of the control window 50 . 52 be adjusted to the lift curve, so that, for example, already turned on before reaching the outer dead center, a pressure medium connection to the tank and according to the displacement of the radial piston motor is reduced. Accordingly, the pressure medium connection to the drain by suitable pivoting of the commutator longer, that is kept open beyond the outer dead center to reduce the displacement. In principle, by such a relative pivoting of the commutator 30 with respect to the lift curve a Phasenanschnitts-, Phasenabschnitts- or phase cut control are set, in which the working space before, after or between the dead centers is connected to the low pressure.

It was found that despite such a phase shift, the noise emission of the relatively slow-running radial piston engine 1 is comparatively low, the stepless adjustability of the absorption volume allows optimal adaptation to different operating conditions and also a pulsation of the pressure medium volume flow can be largely reduced.

Disclosed is a radial piston machine with a variety of radially verschiebaren, stored in a cylinder star piston whose from the Cylinder star outstanding end sections supported on a cam ring are, so that upon rotation of the cylinder star, the piston accordingly perform a stroke given by the lifting ring a hub or by appropriate pressurization and pressure relief the piston rotates the cylinder star relative to the cam ring. One Workspace bounded by each piston and the cylinder star is over a commutator with a pressure medium inlet and a pressure medium outlet connectable. According to the invention, the position of the Commutator with respect to the lift curve in the sense of a phase shift be adjusted.

1

Radial piston motor

2

housing pot

4

housing pot

6

lifting ring

8th

output shaft

10

roller bearing

12

roller bearing

14

external teeth

16

internal gearing

18

cylinder radial

20

bore

22

piston

24

axis

26

working space

27

channel

28

face

30

commutator

32

internal bore

34

bearing seat

38

annulus

40

annulus

42

inlet channel

44

drain channel

46

Inner circumferential surface

48

cam

50

Inlet control window

52

Sequencer window

54

role

56

actuator

58

takeaway

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19832196 A1 [0002]
• - DE 3637174 A1 [0004]
• US 4724742 [0004]
• - DE 19832696 A1 [0018]

Cited non-patent literature

• - "Fundamentals of hydraulics"; Horst-W. Grollius; Fachbuchverlag Leipzig; 3. updated edition; 2006 " [0006]

Claims (6)

Radial piston machine with variable delivery or displacement volume, with a large number of cylinder rotors ( 18 ) radially displaceably guided pistons ( 22 ) attached to a cam ring ( 6 ) and in each case with the cylinder star ( 18 ) a work space ( 26 ), which is over in a commutator ( 30 ) trained control channels ( 42 . 44 ; 50 . 52 ) can be connected to a pressure medium inlet (P) or a pressure medium outlet (T), characterized by an adjusting device ( 56 ) for adjusting a relative position of the commutator ( 30 ) with reference to the lifting ring ( 6 ) in the sense of a phase shift. Radial piston machine according to claim 1, wherein the commutator ( 30 ) is rotatably mounted. Radial piston machine according to claim 2, with an actuator ( 56 ) for rotating the commutator ( 30 ). Radial piston machine according to one of the preceding claims, wherein cylinder star ( 18 ) and cam ring ( 6 ) are arranged centrically to each other. Radial piston machine according to one of the preceding Claims, wherein the phase shift in the sense a phase cutout control takes place. Radial piston machine according to one of the preceding Claims, this being a multi-stroke radial piston engine is executed.