EP3225842B1 - Hydrostatic radial piston machine - Google Patents

Description

The invention relates to a hydrostatic radial piston machine according to the preamble of patent claim 1.

In known hydrostatic radial piston machines, in particular in multi-stroke radial piston machines with adjustable displacement volume, conventional hydraulic solutions for adjusting the displacement volume have a low dynamic. Known mechanical solutions sometimes mean a considerable effort and are predominantly less energy efficient.

In the DE 10 2004 049 864 A1 discloses a hydrostatic displacement machine, in which two cam tracks are rotated against each other for adjusting the displacement volume, which control an actuation of associated pistons in radial bores. The manner of the required precise rotation is not disclosed there, but usually requires a high design and / or manufacturing effort, for example via controlled rotary actuators.

The publication US 2015 035 45 37 A1 shows a generic radial piston machine in which two cam tracks are circumferentially against each other to adjust the displacement volume.

The publication US 2008 006 05 13 A1 shows a radial piston machine, in which by axial adjustment of two rigidly coupled cam profiles of the stroke can be adjusted by supported on the cam profiles working piston of two piston groups.

In contrast, the invention is based on the object to provide a hydrostatic radial piston engine, in which an adjustment of the displacement volume in a simple and energy-efficient manner can be realized.

This object is achieved by a hydrostatic radial piston machine having the features of patent claim 1.

Advantageous developments of the hydrostatic radial piston engine according to the invention are described in the further subclaims.

A hydrostatic radial piston engine according to the present invention includes a first group including a plurality of radially disposed first cylinders, each of which limit first pistons first working spaces. Furthermore, the hydrostatic radial piston machine according to the invention contains a second group, in particular axially spaced from the first group, which contains a plurality of radially arranged second cylinders with which respectively second pistons define second working spaces. In particular, the second group contains the same number of cylinders as the first group. Furthermore, the first working spaces are fluidically connected to respective second working spaces arranged axially adjacent to each of them for a working space pair. The hydrostatic radial piston engine according to the invention further includes a first cam profile associated with the first group for a lifting movement of the first piston and a second cam associated second cam profile for a lifting movement of the second piston, wherein the stroke movement of the first piston with respect to the lifting movement of the second piston is phase-displaceable. According to the invention it is provided that the first cam profile and / or the first group for a first phase shift of the stroke movement of the first piston with respect to the lifting movement of the second piston with respect to each other are axially displaceable.

Due to the axial displaceability of the first cam profile and / or the first group with respect to each other in the hydrostatic radial piston machine according to the invention a simple adjustability with high dynamics can be achieved because the components involved in the adjustment with a Reduced inertia are executable and are easily displaced.

Advantageously, the second cam profile and / or the second group for a second phase shift of the lifting movement of the second piston with respect to the lifting movement of the first piston with respect to each other axially displaceable. Characterized in that, alternatively or in addition to the first cam profile and / or the first group, the second cam profile and / or the second group are axially displaceable with respect to each other, a greater flexibility in the adjustability can be achieved.

Advantageously, the cam profiles have a wave-shaped, in particular sinusoidal, surface whose propagation direction in at least one of the cam profiles extends at an oblique angle of 90 ° to an axial direction, and in particular spirally, or progressively spirally, twisted. The propagation direction is understood to mean a direction in which a wave having a waveform like the surface described would propagate. The described tilt of the cam profiles, in particular their wavy surface, with respect to the axial direction allows depending on the axial displacement a difference in a stroke movement of the pistons in a pair of working spaces, so that they have a phase shift, which causes a change in the displacement volume and thus an adjustment the displacement volume on the axial displacement of the cam profiles and / or the respectively associated group allows. A complete phase corresponds to a period of α = 360 °.

Advantageously, the first phase shift is equal to the second phase shift, which may be referred to as a symmetric phase shift. In this case, for example, the first phase shift -10 ° and the second phase shift + 10 °. A symmetrical phase shift can be achieved with structurally simple because symmetrically constructed components.

Alternatively, the first phase shift may be unequal to the second phase shift, which may be referred to as asymmetric phase shift. For example, the first phase shift may be -15 ° and the second phase shift may be + 5 °. Although possibly the components with which an asymmetric phase shift can be achieved, may be somewhat more expensive in construction and / or manufacture, thus a particular linear characteristic for the hydrostatic radial piston machine according to the invention can be achieved. This means that the axial displacement of the components responsible for the adjustment results in a phase shift which depends directly in proportion to the axial displacement. In this case, the second phase shift may be equal to zero, in particular realized such that an axial displacement of the second cam profile causes no phase shift. For example, in that the propagation direction of the wave-shaped surface in the second cam profile corresponds to a skew angle of 90 ° to the axial direction.

For symmetric as well as asymmetric phase shift, the total phase shift is considered equal to one included by the first phase shift and the second phase shift. If, for example, the first phase shift is -15 ° and the second phase shift is +15 ° in the case of a symmetrical phase shift, this results in an included angle of 30 ° for the total phase shift. For example, with an asymmetric phase shift, the first phase shift is -10 ° and the second is Phase shift + 20 ° results in an included angle of 30 ° for the total phase shift.

Advantageously, the groups are arranged on a stator of the hydrostatic radial piston machine and the cam profiles rotatably, or rotationally fixed and axially displaceable, are arranged on a rotor of the radial piston machine.

Advantageously, the groups are non-rotatable, or rotationally fixed and axially displaceable, are arranged on a rotor of the hydrostatic radial piston engine and arranged the cam profiles on a stator of the radial piston machine.

Advantageously, the rotor is axially displaceable or formed with an axially displaceable sliding sleeve.

Advantageously, the cam profiles are rotatably mounted on the sliding sleeve.

Advantageously, the rotor and / or the stator for the first phase shift and / or the second phase shift with respect to each other is axially displaceable.

The aforementioned variants result in increased flexibility in the design of the hydrostatic radial piston machine according to the invention.

Advantageously, the working space pairs can be connected via non-return valves or through passage openings of a control disk to a high-pressure side or a low-pressure side. If the hydrostatic radial piston engine according to the invention is operated only in a one-quadrant operation The control via non-return valves offers a cost-effective and structurally simple solution. If the hydrostatic radial piston engine according to the invention is to be operated in a four-quadrant operation, the control via the control disk with correspondingly formed passage openings offers an efficient control of the radial piston engine according to the invention.

Advantageously, the control disk is adjustable via an axial displacement of a rotationally fixed and axially displaceable connected to the rotor sliding sleeve to a central position of the respective total phase shift. As described above, the total phase shift results from the included angle.

For example, in the case of the above-described symmetrical phase shift, the middle position is a zero-degree position, that is to say the control disk is not adjusted in the case of a symmetrical phase shift. In the asymmetric phase shift described above, the center position is one half of the included angle of the total phase shift corresponding position. For example, if the first phase shift is -10 ° and the second phase shift is 20 °, then the total phase shift is 30 ° and the center position of the control disk corresponds to a position of 15 °.

Advantageously, the control disk rotates with the rotor. In this way, the hydrostatic radial piston engine according to the invention is controllable via the control disk adjusted in the corresponding middle position, in that the working space pairs can be connected via the passage openings to the respectively correct high-pressure or low-pressure side.

Advantageously, the rotor is designed as a one-piece shaft. As a result, a construction and / or manufacture of the rotor are simplified. A further advantage is that a further output of the rotor according to the invention can be coupled to its drive on the rotor to a respective output of the rotor.

Advantageously, the first cam profile is axially displaceable together with or separated from the second cam profile. The first cam profile may be formed in one piece or in two parts with the second cam profile.

Advantageously, the pistons are supported inside or outside.

Two embodiments of a hydrostatic radial piston machine according to the invention are shown in the drawings. With reference to the figures of these drawings, the invention will now be explained in more detail.

Figur 1

in einem Längsschnitt eine Seitenansicht eines ersten Ausführungsbeispiels einer erfindungsgemäßen hydrostatischen Radialkolbenmaschine in einer ersten Betriebsstellung,

Figur 2

in einem Längsschnitt eine Seitenansicht der erfindungsgemäßen hydrostatischen Radialkolbenmaschine gemäß Figur 1 in einer zweiten Betriebsstellung,

Figur 3

in einem Längsschnitt eine Seitenansicht eines zweiten Ausführungsbeispiels einer erfindungsgemäßen hydrostatischen Radialkolbenmaschine in einer ersten Betriebsstellung, und

Figur 4

die erfindungsgemäße hydrostatische Radialkolbenmaschine gemäß Figur 3 in einer zweiten Betriebsstellung.

Show it

FIG. 1

3 shows a longitudinal section of a side view of a first exemplary embodiment of a hydrostatic radial piston machine according to the invention in a first operating position,

FIG. 2

in a longitudinal section a side view of the hydrostatic radial piston engine according to the invention FIG. 1 in a second operating position,

FIG. 3

in a longitudinal section a side view of a second embodiment of a hydrostatic radial piston engine according to the invention in a first operating position, and

FIG. 4

the hydrostatic radial piston engine according to the invention FIG. 3 in a second operating position.

This in FIG. 1 illustrated first embodiment shows a hydrostatic radial piston machine 1 according to the invention with a first group 2 with a plurality of radially arranged first cylinders 4, with each first piston 6 define first working spaces 8. Axially spaced therefrom is a second group 10 of the radial piston machine according to the invention with a plurality of radially arranged second cylinders 12, with each of which second pistons 14 define second working spaces 16. In the first group 2 the same number of first work spaces 8 are included as in the second group 10 second work spaces 16. The first work spaces 8 are fluidly connected to each of these axially adjacent second work spaces 16 to a pair of working rooms 8,16.

A first cam profile 18 for a lifting movement of the first piston 6 is assigned to the first group 2, and a second cam profile 20 for a stroke movement of the second piston 14 is assigned to the second group 10. For axial adjustment of the cam profiles 18, 20, a hydraulic adjusting mechanism 22 is provided, which will not be discussed in detail here.

The first cam profile 18 is axially displaceable together with the second cam profile 20, wherein the cam profiles 18, 20 are formed in two parts for manufacturing reasons, but are rotatably connected to a on a rotor 26 of the radial piston machine 1 axially slidably mounted sliding sleeve 28. The hydraulic adjusting mechanism 22 acts on the sliding sleeve 28, but may act in a further embodiment on the rotor 26 or on one of the cam profiles 18, 20 or on both cam profiles 18, 20. The cam profiles 18, 20 may also be formed in one piece, in particular in one piece with the sliding sleeve 28. In a further variant, the cam profiles 18, 20 separated from each other axially be displaced, in particular realized with a (not shown) further hydraulic adjusting mechanism.

The cam profiles 18, 20 have a sinusoidal surface whose propagation direction 30 extends at an oblique angle (γ) deviating from 90 ° to an axial direction 32. The direction of propagation is understood to be a direction in which such a wave would propagate. The sinusoidal surface may be spirally twisted, in particular progressively spirally twisted.

The groups 2, 10 are arranged on a stator 24 of the radial piston machine 1 and the cam profiles 18, 20 are non-rotatably arranged on the rotor 26 formed as a one-piece shaft. In a further embodiment, this can be reversed. In the case of the cam profiles 18, 20 are arranged directly on the rotor 26, the rotor 26 is axially displaceable. In a further embodiment, the stator 24 may be axially displaceable with respect to the rotor 26, wherein the hydraulic adjustment mechanism 22 acts on the stator 24.

The working room pairs 8, 16 can be connected to a high-pressure side 38 or a low-pressure side 40 in a one-quadrant operation via correspondingly effective non-return valves 34, 36.

The mode of operation of the radial piston machine according to the invention is described in principle below:
About the axial displacement of the sliding sleeve 28 is a phase shift of the lifting movement of the first piston 6 with respect to the lifting movement of the second piston 14, as a result of the respective piston 6, 14th effective lift curve is changed. The phase of the lifting movements per pair of working space 8, 16 is thus changeable.

In FIG. 1 is shown a phase shift of 0 °, in which add the two stroke volumes of the piston 6, 14 in the pair of working space 8, 16, that is, both strokes of the pistons 6, 14 run synchronously and in the same cycle. The displacement volume is thus adjusted to a maximum, that is to say 100%.

If, as in FIG. 2 shown, the stroke movement of the first piston 6 is phase-shifted by 180 ° with respect to the lifting movement of the second piston 14 in the pair of working chambers 8, 16, then the displacement volume is adjusted such that a stroke volume of the first piston 6 is completely absorbed by the second working space 16 is and vice versa. The displacement volume of the radial piston engine according to the invention is equal to zero. In this case, a first phase shift of the lifting movement of the first piston 6, considered with respect to a non-displaced lifting movement, equal to -90 ° and the second phase shift of the lifting movement of the second piston 14, considered in relation to a non-displaced lifting movement, is + 90 °. The first phase shift is thus set equal to the second phase shift, is a so-called symmetric phase shift.

A value between 0 and 100% of the displacement volume is adjustable by a phase shift between 0 and 180 °.

In FIG. 3 is different from the previously in the FIG. 1 and FIG. 2 described embodiment instead of the check valves 34, 36 shown there, a control disk 42 used to control the radial piston engine 1 according to the invention. The workrooms 8, 16 of each working couple 8, 16 are connectable to a high-pressure side 38 at a working stroke via a through-opening provided on a control disk 42 (not shown) and can be connected to a low-pressure side 40 via a further through-opening provided on the control disk 42 (not shown).

The control disk 42 is adjustable via an axial displacement of the rotationally fixed and axially displaceable connected to the rotor 26 sliding sleeve 28 to a middle position of the respective total phase shift. The control disk 42 rotates with the rotor 26.

The middle position is, for example, in a symmetrical phase shift described above, a zero degree position, that is, the control disk is not adjusted. In an asymmetric phase shift, the center position is one half of the included angle of the total phase shift corresponding position. For example, if the first phase shift is -10 ° and the second phase shift is 20 °, then the total phase shift is 30 ° and the center position of the control disk 42 corresponds to a position of 15 °.

At an in FIG. 4 illustrated operation of the hydrostatic radial piston machine 1 according to the invention as a pump and if, for example, the total phase shift is greater than half the period, where α = 360 °, takes place a pressure side change at the terminals of the high pressure side 38 or a low pressure side 40 instead. The conveying direction of the radial piston pump is reversed with unchanged direction of rotation. In this way, a four-quadrant operation of the radial piston engine 1 according to the invention can be carried out.

Disclosed is a hydrostatic radial piston machine with axially adjacent arranged working space pairs whose work spaces are fluidly connected to each other. An axial displacement of cam profiles for a stroke movement of pistons in the pairs of working spaces, the strokes of the first piston are phase-shifted with respect to the lifting movement of the second piston. In this way, an adjustment of a displacement volume in a simple and energy-efficient manner can be realized.

LIST OF REFERENCE NUMBERS

1

hydrostatic radial piston machine

2

First group

4

First cylinder

6

First piston

8th

First workroom

10

Second group

12

Second cylinder

14

Second piston

16

Second workspace

18

First cam profile

20

Second cam profile

22

Hydraulic adjustment mechanism

24

stator

26

rotor

28

sliding sleeve

30

propagation direction

32

Axial direction

34

check valve

36

check valve

38

High pressure side

40

Low pressure side

42

control disc

γ

Inclination angle

Claims (11)

1. Hydrostatic radial piston machine comprising a first group (2) which contains multiple radially arranged first cylinders (4), with which respective first pistons (6) delimit first working spaces (8), and comprising a second group (10) which contains multiple radially arranged second cylinders, with which respective second pistons (14) delimit second working spaces (16), wherein the first working spaces (8) are connected fluidically to second working spaces (16) each arranged respectively axially adjacent thereto to respectively form a working space pair (8, 16), and comprising a first cam profile (18) assigned to the first group (2) for a reciprocating movement of the first pistons (6), and a second cam profile (20) assigned to the second group (10) for a reciprocating movement of the second pistons (14), wherein the reciprocating movement of the first pistons (6) can be phase-shifted with respect to the reciprocating movement of the second pistons (14),
   characterized in that the first cam profile (18) or the first group (2) can be displaced axially for a first phase shift of the reciprocating movement of the first pistons (6) with respect to the reciprocating movement of the second pistons (14) in relation to one another.
2. Hydrostatic radial piston machine according to Claim 1, wherein the second cam profile (20) or the second group (10) can be displaced axially for a second phase shift of the reciprocating movement of the second pistons (14) with respect to the reciprocating movement of the first pistons (16) in relation to one another.
3. Hydrostatic radial piston machine according to Claim 1 or 2, wherein the cam profiles (18, 20) have a wave-shaped surface, of which the propagation direction (30) in at least one of the cam profiles (18, 20) extends relative to an axial direction (32) at an oblique angle (γ) deviating from 90°.
4. Hydrostatic radial piston machine according to one of Claims 2 and 3, wherein the first phase shift is equal to the second phase shift or the first phase shift is not equal to the second phase shift.
5. Hydrostatic radial piston machine according to one of the preceding claims, wherein the groups (2, 10) are arranged on a stator (24) of the radial piston machine, and the cam profiles (18, 20) are co-rotationally or co-rotationally and axially displaceably arranged on a rotor (26) of the radial piston machine, or wherein the groups (2, 10) are arranged co-rotationally or co-rotationally and axially displaceably on a rotor (26) of the radial piston machine and the cam profiles (18, 20) are arranged on a stator (24) of the radial piston machine.
6. Hydrostatic radial piston machine according to Claim 5, wherein the rotor (26) or the stator (24) can be displaced axially relative to one another for the first phase shift or the second phase shift.
7. Hydrostatic radial piston machine according to one of the preceding claims, wherein the working space pairs (8, 16) can be connected to a high-pressure side (38) or a low-pressure side (40) via non-return valves (34, 36) or via passage openings in a control disc (42).
8. Hydrostatic radial piston machine according to Claim 7, wherein the control device (42) is adjustable to a central position of the respective overall phase shift via an axial displacement of a sliding sleeve (28) co-rotationally and axially displaceably connected to the rotor (26), and revolves with the rotor (26).
9. Hydrostatic radial piston machine according to one of Claims 5 to 8, wherein the rotor (26) is formed as a one-piece shaft.
10. Hydrostatic radial piston machine according to one of Claims 2 to 9, wherein the first cam profile (18) can be displaced axially together with or separately from the second cam profile (20).
11. Hydrostatic radial piston machine according to one of the preceding claims, wherein the pistons (6, 14) are supported internally or externally.

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