EP0180912A2 - Fluidic radial piston machine - Google Patents

Abstract

To change the swallowing or delivery volume of hydraulic radial piston machines, it is known to provide adjusting pistons in the transverse plane of the working piston. The space required for this, however, limits the use to sizes with swallowing or delivery volumes above about 500 cm³. The invention provides a shaft section (6) which can be pivoted with respect to the machine longitudinal axis MLA, possibly telescopic, and which is connected to a force-actuated, translationally active hydraulic cylinder (26) by incorporating a swivel link mechanism (14). The shaft section (6) passes through a supporting member (4) in a space-jointed manner, which is at least indirectly slidably acted upon by the working pistons (2). By appropriately loading the hydraulic cylinder (26), the inclination of the pivotable shaft section (6) relative to the machine longitudinal axis MLA and thereby the swallowing or delivery volume is changed via the swivel link mechanism (14). The connection (5) of the pivotable shaft section (6) with the support member (4) requires little space and enables a continuous change even in sizes with swallowing or delivery volumes below about 500 cm³.

Description

The invention is directed to a fluidic radial piston machine, in particular a hydraulic radial piston machine, according to the features in the preamble of claim 1.

From DE-OS 22 03 054 a radial piston machine belongs to the prior art, which has an eccentric adjustment with hydraulically actuated adjusting pistons provided within the eccentric ring. Such a design has proven itself wherever the eccentric ring could be dimensioned large enough due to the construction volume of the machine to accommodate adjusting pistons with a still satisfactory adjusting force. However, it can only run reliably in the eccentricity end positions because the adjusting pistons cannot be fixed in intermediate positions. It is therefore a machine that can be switched in two stages.

Eccentric adjustments with continuously working adjusting pistons within an eccentric ring are known from DE-PS 26 54 526. However, one needs here for Accommodation of double-acting unlockable check valves, which are arranged in a bearing journal of the machine in the immediate vicinity of the adjusting cylinders, additional installation space. The stepless adjustability is therefore also limited: with stable intermediate positions to machine sizes, the volume (displacement volume of a radial piston motor, delivery volume of a radial piston pump) is limited to a minimum of approximately 500 cm ³ .

In the case of sizes with a volume of less than approximately 500 cm ', it has hitherto been limited exclusively to the stepwise adjustment, the piston shutoff being mostly used as the functional principle (DE-OS 31 09 706). If you cut off individual pistons from the pressure supply with the help of upstream valves, you get a machine that can be switched in two or more ratios. However, the construction principle cannot be applied to engines in which the pistons are positively held on the machine shaft (crankshaft). Also, the motors cannot normally be switched over during the run.

The invention has for its object to develop the hydraulic radial piston machine described in the preamble of claim 1 so that even with comparatively small sizes with a swallowing or delivery volume below about 500 cm ^3, a continuous change in the swallowing or delivery volume can be ensured.

This object is achieved according to the invention in the features listed in the characterizing part of claim 1.

For the stepless radial displacement of the support member loaded by the working piston, a longitudinal section of the machine shaft is now designed to be pivotable. The pivoting is based on a force-actuated, translato- rically effective sliding member, the translatory force direction of which is converted into a radial force direction via the swivel arm gear arranged next to the common transverse plane of the working piston. The adjustment mechanism is now next to the row of pistons. Consequently, the support member can now be made very small. It is only necessary that it can be coupled to the longitudinal section of the machine shaft pivotable from the machine longitudinal axis in such a way that the rotation, a slight relative movement to the working piston due to the pivoting shaft section and the pivoting movement of the shaft section relative to the support member is ensured. As a result, the support member shrinks to a size which allows radial piston machines with a swallowing or delivery volume below approximately 500 cm ^{3 to} be continuously adjusted without difficulty.

The features of claim 2 embody an embodiment in which no fixed connection is provided between the swivel link transmission and the hydraulic cylinder which can be acted upon on one side. The hydraulic cylinder therefore does not need to be rotatable. Nevertheless, the return spring in the swivel link mechanism ensures that the swiveling shaft section is shifted into the longitudinal axis of the machine and thus swallows or swallows even when depressurized

Funding volume becomes zero. On the other hand, by appropriately loading the hydraulic cylinder, the inclination of the pivotable shaft section relative to the longitudinal axis of the machine and thus the swallowing or delivery volume can be changed continuously.

In the case of the features of claim 3, a fixed connection of the double-acting hydraulic cylinder with the swivel link mechanism is provided. However, such a connection requires a rotatable connection between the hydraulic cylinder and the swivel link transmission. This can e.g. B. the pivot axis between the piston rod and the compensating link. The piston rod or the piston can also be rotatably supported, if necessary. In this embodiment, however, the piston rod space should always be acted upon by the pressure medium such that the pivotable shaft section is aligned in the longitudinal axis of the machine in the case of unpressurized working cylinders. This can also be brought about by a spring which is provided, for example, in the piston rod space.

If the pivotable shaft section is rigid over its entire length in accordance with the features of claim 4, it is advantageous if the support member is arranged to be displaceable parallel to the machine longitudinal axis relative to the working piston. In this way, the fact is taken into account that the space hinge between the pivotable shaft section and the support member, when the shaft section changes in inclination to the machine longitudinal axis, travels an arcuate path which no longer runs in the common transverse plane of the central axes of the working pistons.

The above-described, pressurized sliding elements in the form of hydraulic cylinders are always in line with their longitudinal axes in line with the machine longitudinal axis and are also arranged as an extension of the pivotable shaft section if this - is located in the machine longitudinal axis. In the embodiment characterized in claim 5, the pivotable shaft section itself is designed as a sliding member. The telescopic cylinder can be acted upon on one side or on both sides. Since the cylinder housing also performs a pivoting movement about the articulation point on the axially non-displaceably mounted longitudinal section of the machine shaft, it is necessary to design the support member connected to the cylinder housing in such a way that the working pistons can be supported on the support member in a spatially articulated manner. For this purpose, the support member can have spherical-segment-shaped surfaces, on which connecting rods connected in an articulated manner to the working pistons are supported. The support member can also be used in the embodiments as described with reference to claims 2 to 4.

Depending on the type of loading of the telescopic shaft section, it may be expedient in the context of the invention to additionally provide a force-actuated, translationally effective sliding member, as has been previously described in the scope of a hydraulic cylinder that can be loaded on one or both sides.

When using an abutment according to the features in claim 6, the rigid or telescopic swivel shaft section passes through the abutment, which is designed, for example, in a disk or plate-like manner, that the abutment can be taken in the sense of rotation, - but it is still ensured that the shaft section in the abutment through- the desired radial relative displacement. can lead. When force is exerted on the joint between the two pivot links connected to one another, the angle between the pivot links is changed and in this way also the angle of inclination of the pivotable shaft section to the longitudinal axis of the machine. The support member is shifted accordingly, thereby changing the swallowing or delivery volume.

According to the features of claim 7, the swivel link transmission can also have only a single swivel link, which is articulated on the one hand to the abutment and on the other hand to the end of the shaft section which can be pivoted out of the machine longitudinal axis. This embodiment of a swivel link transmission is preferably used, for example, if the pivotable shaft section is designed as a hydraulic cylinder and a further hydraulic cylinder acts as a sliding member on the swivel link transmission, directly or indirectly. It can also be used with advantage if a further pivotable shaft section of a second row of pistons is also struck on the pivoting link. This can be a rigid or telescopic shaft section.

If only one pivotable shaft section is provided, then it is advantageous according to claim 8 that a compensating link is provided between the pivot link transmission and the hydraulic cylinder as a sliding member, which compensates for the spatial changes of the pivot link relative to the machine longitudinal axis.

Are two rows of pistons with two swiveling and telescopic shaft sections with a swivel arm. Gearbox coupled with only one swivel arm, the rotating abutment is expediently axially immovable (claim 9). Since a length compensation takes place within the telescopic shaft sections, the articulation points on the longitudinal sections of the machine shafts rotating in the machine longitudinal axis do not need to be changed in their operating position.

It is also conceivable according to the features of claim 10 that the rotating abutment is arranged axially displaceable. This can be practiced both in an embodiment with only one row of pistons and in an embodiment with two rows of pistons. In this case, the abutment itself forms the sliding link to a certain extent, the actuating means for displacing the sliding link being hydraulic, pneumatic, electrical or mechanical in nature. However, in the embodiment with two rows of pistons, it is necessary to mount one of the articulation points between a pivotable rigid shaft section and the associated longitudinal section of the machine shaft rotating in the machine longitudinal axis in the direction of the machine longitudinal axis. However, this measure can be omitted if one of the shaft sections is designed to be telescopic.

The invention is explained in more detail below on the basis of exemplary embodiments illustrated in the drawings. Figures 1 to 6 show a schematic representation of various radial piston motors with swivel shaft adjustments.

The radial piston motor 1 illustrated in FIG. 1 comprises, for example, five working pistons 2, the central axes of which are arranged in a transverse plane QE common to the machine longitudinal axis MLA. the working pistons 2 slide radially in working cylinders 3. They are supported on a supporting member 4 which is displaceable relative to the working pistons 2 parallel to the machine longitudinal axis MLA.

The support member 4 is connected via a space joint 5 to a rigid shaft section 6 which can be pivoted radially from the machine longitudinal axis MLA. The end 9 of the pivotable shaft section 6 opening into the machine longitudinal axis MLA is hinged in space-like fashion to a longitudinal section 7 of the machine shaft 8 which rotates about the machine longitudinal axis MLA but is axially immovable.

The end 10 of the pivotable shaft section 6, which is radially displaceable from the machine longitudinal axis MLA, passes through a slot 11 of a disk-like abutment 12, which rotates about the machine longitudinal axis MLA, but is axially immovable. The slot-like bushing 11 in the abutment 12 for the shaft section 6 is dimensioned such that the abutment 12 can be carried along perfectly in the direction of rotation by the shaft section 6 and the shaft section 6 can be radially displaced in the slot 11.

The end 10 of the shaft section 6, which can be pivoted out of the machine longitudinal axis MLA, is articulated on a swivel arm 13 of a swivel arm transmission 14. The pivot axis 15 runs at a distance next to the machine longitudinal axis MLA and perpendicular to this. The swivel arm gear 14 comprises a further swivel arm 16 which is articulated on the one hand to a bracket 17 connected to the abutment 12 and on the other hand to the swivel arm 13. Both the swivel axis 18 between the two swivel arms 13 and 16 and the swivel axis 19 between the bracket 17 and the swivel arm 16 extend next to the machine longitudinal axis MLA and perpendicular to it.

At the pivot axis 18, a slider 20 is further articulated, which is under the influence of a spring 21 arranged between the abutment 12 and the pivot axis 18.

The slider 20 is supported in an unconnected manner on a plunger 22 of a hydraulic cylinder 23 which can be acted upon on one side and whose longitudinal axis 24 coincides with the machine longitudinal axis MLA.

When the radial piston motor 1 is not under pressure and the hydraulic cylinder 23 is also not under pressure, the return spring 21 presses the plunger 22 into the cylinder housing 25 and thus also shifts the shaft section 6 into the machine longitudinal axis MLA. The swallowing volume is then zero. By appropriately acting on the hydraulic cylinder 23 against the restoring force of the spring 21, the plunger 22 can now be pushed out, the pivotable shaft section 6 and thereby also the support member 4 being radially displaced via the slide 20 and the swivel link mechanism 14. In this way, the swallowing volume of the radial piston motor 1 can be varied continuously.

In the embodiment of a radial piston motor 1 according to FIG. 2, the hydraulic cylinder 23 which can be acted on on one side has been replaced by a hydraulic cylinder 26 which can be acted on on both sides. The hydraulic cylinder 26 comprises a piston 27 with a piston rod 28, which is articulated via a compensating link 29 to a swivel link transmission 14 according to FIG. In addition to the swivel arm transmission 14, the other components of this embodiment are designed in accordance with the embodiment of FIG. 1. A further explanation is therefore unnecessary.

Due to the direct connection of the hydraulic cylinder 26 to the swivel link mechanism 14, however, it is necessary, for example, to mount the piston rod 28 or the piston 27 of the hydraulic cylinder 26 such that they can rotate. Such a connection can also in the pivot axis 30; be provided between the piston rod 28 and the compensating link 29. In addition, it may be expedient to arrange a compression spring 32 in the piston rod space 31. This compression spring 32 has the purpose of displacing the pivotable shaft section 6 back into the machine longitudinal axis MLA when the radial piston motor 1 'is depressurized. However, this measure can also be carried out by correspondingly pressurizing the piston rod chamber 31. In addition, the compensating link 29 can be used as a variable unbalance compensating member.

In the radial piston motor 1 "illustrated in FIG. 3, the pivotable shaft section is designed as a hydraulically actuable telescopic cylinder 33. The telescopic cylinder 33 can be acted on on one side or on both sides. A support member 35 is attached to the housing 34 spherical segment-shaped surfaces. Appropriately designed connecting rod shoes 36, which are articulated to the working pistons 2, are supported on these surfaces.

The end 9 of the shaft section 6 opening into the machine longitudinal axis MLA is connected in a spatially articulated manner to the axially immovable length section 7 of the machine shaft 8 rotating in the machine longitudinal axis MLA.

The telescopic longitudinal section 37 of the telescopic cylinder 33 passes through a disk-like abutment 38 which rotates about the machine longitudinal axis MLA, but is mounted immovably in the direction of the machine longitudinal axis MLA. For this purpose, the abutment 38 has a slot 39 through which the telescopic part 37 passes so that the abutment 38 is carried in the direction of rotation and the telescopic part 37 can be displaced radially.

The abutment 38 forms part of a swivel arm gear 40 which has a swivel arm 41 which is connected on the one hand via a swivel axis 42 to a bracket 43 connected to the abutment 38 and on the other hand via a swivel axis 44 to the telescopic part 37 of the telescopic cylinder 33. Both pivot axes 42 and 44 extend laterally next to the machine longitudinal axis MLA and perpendicular to it.

A bracket 45, to which a compensating link 46 is articulated, is fastened approximately in the middle of the swivel arm 41. The other end section of the compensating link 46 is connected in an articulated manner via a joint 30 to a piston rod 28 of a hydraulic cylinder 26, as has been described, for example, with reference to FIG.

Depending on the type of loading of the pivotable telescopic cylinder 33, the hydraulic cylinder 26 forming the sliding member can also be acted upon mechanically by a spring 32 in the piston rod space 31 or hydraulically in the piston rod space 31 or, if appropriate, also in the piston space 47.

FIG. 4 shows an embodiment of a radial piston motor 2 ′ ″ with two rows of working pistons 2. An arrangement of the adjustment as shown in FIG. 3 is selected, but with the exception of the hydraulic cylinder 26. This is in the embodiment of the figure 4 can be dispensed with, since the inclination of the telescopic cylinder 33 towards the longitudinal axis MLA of the machine can be changed via the swivel link mechanism 40 and thus the swallowing volume by appropriate loading.

The embodiment according to FIG. 5 shows a radial piston motor 1 "" with a rigid pivotable shaft section 6 and a row of pistons according to the embodiments of FIGS. 1 and 2. However, the end 10 of the shaft section 6 which is pivotable from the machine longitudinal axis MLA is coupled to a swivel arm gear 40, as has been explained with reference to FIG. 3. The difference is further that the abutment 38 is now axially displaceable.

The actuating means required for this can be of a hydraulic, pneumatic, electrical or mechanical nature. It can be seen that by adjusting the abutment 38 parallel to the machine longitudinal axis MLA in the operating position with broken lines, the inclination of the pivotable shaft section 6 to the machine longitudinal axis MLA and thus the displacement volume of the radial piston motor 1 "" can be changed.

In principle, the same possibility also exists for a radial piston engine 1 "" 'with two working piston rows A, B according to the embodiment in FIG. 6. Here, the pivotable shaft section 6 of the second piston row B is also at the articulation point 44 of the swivel arm 41 with the shaft section 6 of the first piston row A connected. However, in this embodiment it is necessary to arrange the articulation point 48 of the pivotable shaft section 6 of the second working piston row B with the associated length section 7 of the machine shaft 8 rotating in the machine longitudinal axis MLA in the direction of the machine longitudinal axis MLA. Such displaceability can be dispensed with if the pivotable shaft section 6, in accordance with the embodiment of FIGS. 3 or 4, is designed as a hydraulic cylinder 33 which can be acted upon on one or on both sides.

List of reference symbols

• 1 radial piston motor
• 2 working pistons
• 3 working cylinders
• 4 support link
• 5 space joint
• 6 shaft section
• 7 length section from 8th
• 8 machine shaft
• 9 end of 6
• 10 "
• 11 slot in 12
• 12 abutments
• 13 swivel arms
• 14 swivel link transmission
• 15 swivel axis between 10 u. 13
• 16 swivel arms
• 17 console
• 18 swivel axis between 13 u. 16
• 19 "between 16 and 17
• 20 slider
• 21 spring
• 22 Plunger v. 23
• 23 hydraulic cylinders
• 24 longitudinal axis v. 23
• 25 cylinder housing
• 26 hydraulic cylinders
• 27 pistons from 26
• 28 piston rod v. 26
• 29 equalizer link
• 30 swivel axis between 28 u. 29
• 31 piston rod space
• 32 compression spring in 31
• 33 telescopic cylinders
• 34 housing v. 33
• 35 support member
• 36 connecting rods
• 37 telescopic part of 33
• 38 abutments
• 39 slot in 38
• 40 swivel link transmission
• 41 swivel arms
• 42 swivel axis
• 43 console
• 44 swivel axis
• 45 console
• 46 equalizer link
• 47 piston chamber v. 26
• 48 pivot point from 6

• 1' Radialkolbenmotor
• 1" "
• 1'" "
• 1"" "
• 1""' "
• A Arbeitskolbenreihe
• B "

MLA machine longitudinal axis QE transverse plane

• 1 'radial piston motor
• 1""
• 1'""
• 1"""
• 1""'"
• A row of working pistons
• B "

Claims (10)

1. Fluidic radial piston machine, in particular hydraulic radial piston machine, the volume of which is infinitely variable and in which the working pistons, with their central axes in a transverse plane common to the longitudinal axis of the machine, bear at least indirectly slidingly on a support member connected to the machine shaft and displaceable radially to the machine shaft, characterized in that the longitudinal section (6, 33) of the machine shaft (8) passing through the common transverse plane (QE) of the working pistons (2) from the longitudinal axis (MLA) of the machine (1, 1 ', 1 ", 1"', 1 "", 1 "" ') is pivotable and is connected in a space-articulated manner to the support member (4, 35) which is relatively movable relative to the working piston (2), the end (9) of the pivotable shaft section (6, 33) opening into the machine longitudinal axis (MLA) being connected to the the machine longitudinal axis (MLA) rotating, axially immovable length section (7) of the machine shaft (8) hinged in a spatially articulated manner and that from the machine longitudinal axis (MLA) radially displaceable end (13, 37) of the shaft section (6, 33) incorporating a force-actuated, translationally effective sliding member (23, 26, 33) with a swivel link mounted rotatably about the machine longitudinal axis (MLA) next to the transverse plane (QE) Gear (14, 40) with swivel axes (15, 18, 19; 42, 44) is coupled in a rotational sense. 2. Radial piston machine according to claim 1, characterized in that the sliding member consists of a hydraulic cylinder (23) which can be acted upon on one side, the longitudinal axis (24) of which corresponds to the longitudinal axis of the machine (MLA) and the axially movable part (22) of one against the elastic restoring force of one Spring (21) displaceable slider (20) is supported, which is pivotally connected to the swivel link mechanism (14). 3. Radial piston machine according to claim 1, characterized in that the sliding member consists of a double-acting hydraulic cylinder (26), the longitudinal axis of which corresponds to the machine longitudinal axis (MLA) and the piston rod (28) by a compensating link (29, 46) with the swivel arm. Gear (14, 40) is connected. 4. Radial piston machine according to one of claims 1 to 3, characterized in that the pivotable shaft section (6) is rigidly formed over its entire length and the support member (4) connected to this articulated joint is displaceable parallel to the machine longitudinal axis (MLA). 5. Radial piston machine according to one of claims 1 to 3, characterized in that the pivotable shaft section as hydraulically actuated Beatable telescopic cylinder (33) is formed, the housing (34) carries the support member (35) on which the working piston (2) is supported in a space-articulated manner. 6. Radial piston machine according to one of claims 1 to 3, characterized in that the swivel link gear (14) rotates parallel to the transverse plane (QE) about the longitudinal axis of the machine (MLA) and is rotatable by the pivotable shaft section (6) in the direction of rotation and radially relatively displaceable has an axially immovable abutment (12), to which a swivel arm (16) is articulated at a radial distance from the machine longitudinal axis (MLA), which swivel arm (16) is hinged to the end (10) of the shaft section (6). 13) as well as with the slide (20) or with the compensating link (29). 7. Radial piston machine according to one of claims 1 to 3, characterized in that the swivel link gear (40) parallel to the transverse plane (QE) about the longitudinal axis of the machine (MLA) rotatable and rotatable by the pivotable shaft section (6, 33) in the direction of rotation and has a radially displaceable abutment (38) to which a swivel arm (41) hinged at the other end to at least one pivotable shaft section (6, 33) is fastened at a radial distance from the longitudinal axis of the machine (MLA). 8. Radial piston machine according to claim 7, characterized in that in the central longitudinal region of the swivel arm (41) on the other hand with the piston rod (28) of an at least piston rod-side hydraulic cylinder (26) articulated compensating link (46) is articulated. 9. Radial piston machine according to claim 7, characterized in that the rotating abutment (12, 38) is axially immovable. 10. Radial piston machine according to claim 7, characterized in that the rotating abutment (38) is axially displaceably mounted and subjected to the influence of adjusting means.

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