EP2940299A2 - Axial piston engine with inclined axes - Google Patents

Abstract

The invention relates to a hydrostatic axial piston machine (1) in a bent-axis design with a about a rotational axis (R t) rotatably within a housing (2) arranged drive shaft (4), with a about an axis of rotation (R t) rotatably disposed within the housing (2) Drive flange (3), and with a about an axis of rotation (R z) rotatably within the housing (2) of the axial piston machine (1) arranged cylindrical drum (7), wherein the cylinder drum (7) is provided with a plurality Kolbenausnehmungen (8), in which in each case a piston (10) is arranged longitudinally displaceable, wherein the pistons (10) are hinged to the drive flange (3) and for articulated attachment of the piston (10) on the drive flange (3) is provided in each case a ball joint connection (20) from a spherical cap-shaped receiving tray (3a) in an end face (3b) of the drive flange (3) and a ball head (10b) is formed, which is in operative connection with the piston (10). According to the invention, the receiving shells (3a) are each in the form of hemispheres extending up to the ball equator, and a retaining web (30) is formed on an end face (3b) of the drive flange (3) in the region of the receiving shells (3a), which extends over the ball equator Hemisphere extends to engage around the ball head (10b) at an angle greater than 180 degrees.

Description

The invention relates to a hydrostatic axial piston machine in oblique-axis construction with an about a rotation axis rotatably disposed within a housing drive shaft, with a about a rotation axis rotatably disposed within the housing drive flange, and with a about an axis of rotation rotatably disposed within the housing of the axial piston cylinder cylinder, wherein the cylinder drum is provided with a plurality Kolbenausnehmungen, in each of which a piston is arranged longitudinally displaceable, wherein the pistons are hinged to the drive flange and for articulated attachment of the piston to the drive flange each a ball joint connection is provided, consisting of a kugelkalottenförmigen receiving tray in a front side of the drive flange and a ball head is formed which is in operative connection with the piston.

In hydrostatic axial piston machines in bent-axis design, the piston arranged longitudinally displaceably in the cylinder drum are usually fastened by means of a ball joint to the drive flange of a drive shaft. The piston forces are based here on the piston on the drive shaft located on the drive flange and generate a torque. In axial piston machines in bent-axis design, it is necessary to attach the piston articulated to the drive flange. For this purpose, ball joint connection is used, which consist of a kugelkalottenförmigen receiving tray in an end face of the drive flange and a ball head, which is arranged on the piston and is inserted into the receiving tray of the drive flange.

In operation, the ball heads of the pistons are to be locked in the respective receiving shell of the drive flange.

For this it is from the WO 2004/109107 A1 known to thread a hold-down plate with openings for the piston heads and molded on the openings spherical caps on the piston and bolt with the drive flange. Due to the required hold-down plate, which has a high production cost due to the spherical caps, and the screw connections for screwing the hold-down plate to the drive flange, such axial piston machines have a high construction cost.

To avoid the construction costs for the additional hold-down plate, it is already out of the EP 0 567 805 B1 , of the EP 1 071 884 B1 , of the DE 40 24 319 A1 and the EP 0 697 520 B1 known to secure the ball heads in the spherical cap receiving tray form-fitting. For this purpose, the kugelkalottenförmigen receiving tray are designed with a wrap of greater than 180 ° degrees, so that the receiving cups wrap around the Kugeläquator, and the ball heads with a cylindrical surface, for example by flattening or processing of the ball head, provided so that the ball head in a certain Position can be introduced by means of the cylindrical surfaces in the spherical cap-shaped receiving tray and then secured by tilting in the receiving tray. The manufacture of the components simplifies this and there is a simple assembly of the piston with the ball heads in the receiving shells of the drive flange.

In the EP 0 567 805 B1 and the EP 1 071 884 B1 the cylindrical surfaces are arranged parallel to the longitudinal axis of the piston, so that the pistons are threaded during assembly coaxial with the axis of rotation of the drive flange in the receiving trays and with the tilting of the piston to the working angle, the piston heads are locked in the receiving trays. When trained as adjusting oblique axis machines, however, the problem may occur in such a locking of the piston in the receiving shells that the coverage of the ball heads in the receiving shells with decreasing pivot angle of the cylinder drum is too low, so that such locking the ball heads of the piston in the drive flange only conditionally suitable for adjusting machines with variable tilt angle of the cylinder drum. For adjusting with a pivot angle of 0 ° degrees, these locks are not suitable because the pistons can not be kept safe in receiving trays and can fall out of the receiving trays.

In the DE 40 24 319 A1 and the EP 0 697 520 B1 the cylindrical surfaces are arranged obliquely to the longitudinal axis of the piston, wherein the inclination angle of the cylindrical surfaces is designed such that this angle does not occur during operation of the axial piston machine. As a result, this lock is suitable for adjusting machines and allows even with a pivot angle of 0 ° degrees locking the piston in the receiving shells of the drive flange. For mounting the piston in the drive flange, the piston must be tilted accordingly strong, so that it may be necessary to provide on each receiving tray a complex to produce recess as a work-free for the piston rod of the piston. Depending on the mounting angle of the piston, this required for the assembly of the piston recess on the receiving shell of the drive flange extend to the Kugeläquator, whereby the kugelkalottenförmige receiving tray in the area is correspondingly greatly reduced.

In the from the EP 0 567 805 B1 , of the EP 1 071 884 B1 , of the DE 40 24 319 A1 and the EP 0 697 520 B1 known Axialkolbenmaschinen results from the looping of greater than 180 ° degree of the spherical cap receiving shells a corresponding large thickness of the drive flange, which leads to a corresponding space requirement in the axial direction of the axial piston engine, since the rotating cylinder drum with the piston outlet openings containing end face not to the front of the Triebflansches may strike, in which the receiving trays are arranged.

The present invention has for its object to provide an axial piston machine in Schrägachsenbauweise available in which the locking of the piston in the drive flange has a simple manufacture and allows to reduce the axial dimensions of the axial piston machine.

This object is achieved in that the receiving shells are each formed as extending to the Kugeläquator hemispheres and on a front side of the drive flange in the receiving shells a retaining web is formed, which extends over the ball equator of the hemisphere to the ball head with a Encompass angles greater than 180 degrees. In the axial piston machine according to the invention, the hollow spherical receiving shells in the drive flange are formed only as hemispheres, which extend up to the ball equator. To secure the ball heads in these hemispherical receiving shells form fit, is on the front side of the drive flange in Area of the receiving shells formed from the front side of the drive shaft projecting retaining web which extends over the ball equator of the hemisphere. The looping of the ball heads beyond the Kugeläquator thus takes place only in the region of the retaining web, so that only the arranged on the end face of the drive flange retaining web secures the piston in the receiving cups and forms the retention of the piston. Due to the spatial limitation of the retention of the ball heads on the region of the arranged on the end face of the drive flange retaining web, it is possible to reduce the remaining area of the end face of the drive flange relative to the retaining web in thickness, so that a clearance is achieved and the cylinder drum with the the piston outlet openings containing end face can be brought closer to the drive flange. This makes it possible to reduce the axial space requirement of the axial piston machine. Compared with the known axial piston machines in Schrägsachsenbauwese results in the axial piston according to the invention by the spatial limitation of the retention of the piston in the receiving shells on the retaining web also a low construction cost.

According to an advantageous embodiment of the invention, the retaining web forms on each receiving tray each two retaining portions, which are arranged opposite to the receiving tray and go beyond the hemisphere. With two opposing retaining portions, it is possible in a simple manner to surround the ball head in the equatorial region in order to hold the ball head in the receiving circuit in a form-fitting manner.

With regard to a low construction costs, special advantages arise when the retaining web is formed by an annular increase on the front side of the drive flange. An annular increase on the front side has a low construction cost. In addition, the annular elevation in the manufacture of the hemispherical receiving shells in the drive flange can be interrupted in a simple manner to form on each receiving tray two oppositely arranged retaining sections.

With particular advantage, the center of the retaining web forming annular increase is arranged on the axis of rotation of the drive flange. By such a concentric arrangement of the annular increase to Rotation axis of the drive flange, the contour of the annular increase can be made in a simple and cost-effective manner by a turning operation.

Advantageously, the annular elevation is arranged in the region of a pitch circle on which the centers of the hemispheres are arranged. As a result, a secure mounting of the ball heads in the receiving shells can be achieved by means of the retaining web. In addition, this creates a corresponding free space, which makes it possible to bring the cylinder drum close to the drive flange in order to achieve compact axial dimensions of the axial piston machine.

With regard to a simple production of the engine, there are particular advantages if the retaining web is formed integrally on the end face of the drive flange. If the retaining web formed out with a corresponding allowance to a blank of the drive flange, the drive flange and the retaining web can be made in a simple and cost-effective manner as a rotating part by a turning.

In order to mount the ball heads in the associated receiving shells, each ball head is provided with two oppositely arranged grooves according to an advantageous embodiment of the invention, wherein the distance between the groove bottom of the two grooves is smaller than the opening width of the two retaining portions on the respective receiving tray. This makes it possible in a simple manner to thread the ball heads by means of the two grooves between the retaining sections in the receiving tray, so that a simple assembly of the piston is achieved in the receiving trays.

Advantageously, in this case the groove width of the grooves is greater than the width of the retaining web. Due to the two opposing grooves, which have only a small width as the retaining web, it is thus further achieved that the ball half of the ball head, which supports the piston force, is only slightly reduced in area by the relatively small width of the two grooves, so that high cylinder forces can be supported.

The grooves can be arranged perpendicular or parallel to the longitudinal axis of the piston. With particular advantage, the grooves are arranged on the ball head obliquely inclined to the longitudinal axis of the piston. Depending on the angle of inclination of the grooves, it may be possible in the axial piston machine according to the invention to dispense with free work on the receiving shells for the piston rods for mounting the piston, as already by the opposite the retaining web recessed front side of the drive flange a corresponding space for the piston rods for mounting the piston is created. If, at a correspondingly high angle of inclination of the grooves, a recess is required as machining on the end face of the drive flange in the region of the receiving shells for the piston shank of the pistons in order to permit assembly of the pistons in the drive flange, a smaller one results in the axial piston machine according to the invention compared to known axial piston machines Depth of the recess and thus a smaller clearance in the front of the drive flange. Preferably, the grooves are not arranged perpendicular to the longitudinal axis of the pistons, resulting in respect of vertically arranged grooves smaller workouts on the receiving cups for the piston rods for mounting the piston. By minor workouts for the piston rod of the piston is achieved that the surface of the spherical cap of the receiving tray, in which the piston force is supported in the axial piston machine according to the invention is only slightly reduced in area. In addition, by obliquely arranged grooves, the locking of the pistons in the drive flange for bent axis machines with a pivot angle of 0 ° degrees suitable.

The inclination angle of the grooves is advantageously designed such that the inclination angle is different from the tilting angles of the pistons occurring during operation of the axial piston machine. Advantageously, the angle of inclination is such that, during assembly, the inclination of the pistons toward the axis of rotation of the drive flange is greater than the maximum inclination of the pistons during operation of the oblique axis machine, so that the pistons are safe in operation of the axial piston machine with the ball heads in the receiving shells of the drive flange can be held positively.

Advantageously, a recess for a piston rod of the piston is formed on the drive flange on each receiving tray in order to achieve a simple mounting of the piston in the drive flange with obliquely arranged grooves.

According to an advantageous embodiment of the invention, a spherical guide is designed to guide the cylinder drum between the drive flange and the cylinder drum. With such a spherical guide, which is preferably formed by a spherical portion of the drive flange or the drive shaft and a hollow spherical portion of the cylinder drum, a simple, inexpensive and space-saving guidance and storage of the cylinder drum can be achieved.

Appropriately, in this case, the recesses are formed on the radially outer portion of the receiving shells in the end face of the drive flange. By radially outer recesses arranged in an axial piston machine with a spherical guide the cylinder drum a simple assembly of the piston by tilting the piston radially outward possible.

If the drive flange is provided with a chamfer on the outer edge of the end face, the recess possibly required for the piston rod of the piston can be produced as a work-in-progress without additional production outlay, if the chamfer is dimensioned such that the chamfer forms the recess for the piston rod of the piston ,

The grooves in the ball heads of the pistons may have a straight course.

Particular advantages can be achieved if the grooves have a bent course. Compared with straight grooves is achieved by grooves with a bent course that the load-bearing ball half of the ball head has a larger area, so that higher piston forces can be transmitted.

The grooves expediently have a first portion, which is arranged obliquely inclined to the longitudinal axis of the piston, and a second portion, which is bent over the first portion, in particular arranged perpendicular to the longitudinal axis of the piston.

Figur 1

eine erfindungsgemäße Axialkolbenmaschine in Schrägachsenbauweise in einem Längsschnitt,

Figur 2

einen Ausschnitt der Figur 1 in einer vergrößerten Darstellung,

Figur 3

eine Draufsicht auf die Stirnseite des Triebflansches,

Figur 4

einen Schnitt entlang der Linie B-B der Figur 3,

Figur 5

einen Schnitte entlang der Linie A-A der Figur 4,

Figuren 6a-6d

Darstellungen zur Verdeutlichung der Montage der Kolben,

Figuren 7a-7d

perspektivische Darstellungen zur Verdeutlichung der Montage der Kolben,

Figuren 8a-8d

weitere perspektivische Darstellungen zur Verdeutlichung der Montage der Kolben,

Figuren 9a-9c

mehrere Darstellungen gemäß einer Linie C-C der Figur 3 mit unterschiedlichen Neigungswinkeln der Kolben,

Figuren 10a-10c

mehrere perspektivische Darstellungen eines in der Aufnahmeschale montierten Kolbens,

Figur 11a

eine erste Ausführungsform eines Kolbens und

Figur 11b

eine zweite Ausführungsform eines Kolbens.

Further advantages and details of the invention will be explained in more detail with reference to the embodiments illustrated in the schematic figures. This shows

FIG. 1

an axial piston machine according to the invention in a bent-axis design in a longitudinal section,

FIG. 2

a section of the FIG. 1 in an enlarged view,

FIG. 3

a plan view of the end face of the drive flange,

FIG. 4

a section along the line BB of FIG. 3 .

FIG. 5

a section along the line AA the FIG. 4 .

Figures 6a-6d

Illustrations to illustrate the assembly of the pistons,

FIGS. 7a-7d

perspective views to illustrate the assembly of the piston,

Figures 8a-8d

further perspective views to illustrate the assembly of the piston,

Figures 9a-9c

several representations according to a line CC of FIG. 3 with different angles of inclination of the pistons,

Figures 10a-10c

several perspective views of a piston mounted in the receiving tray,

FIG. 11a

a first embodiment of a piston and

FIG. 11b

a second embodiment of a piston.

The hydrostatic axial piston machine 1 according to the invention designed as a bent-axis machine according to the FIG. 1 has a housing 2, which consists of a housing member 2a and a housing cover 2b, which is fixed to the housing member 2a. In the housing 2, a drive flange 3 and a drive shaft 4 are arranged rotatably about a rotation axis R _t , which corresponds to a longitudinal axis L of the axial piston machine 2. In the illustrated embodiment, the drive shaft 4 is rotatably supported by bearing means 5a, 5b about the rotation axis R _t . The drive flange 3 is integrally formed on the drive shaft 4 in the illustrated embodiment.

Axially adjacent to the drive flange 3, a cylinder drum 7 is arranged in the housing 2, which is arranged rotatably about an axis of rotation R _z and provided with a plurality Kolbenausnehmungen 8, which are arranged in the illustrated embodiment concentric with the axis of rotation R _{z of} the cylinder drum 7. In each piston recess 8, a piston 10 is arranged longitudinally displaceable.

The rotation axis R _{t of} the drive shaft 4 intersects the rotation axis R _{z of} the cylinder drum 7 at the point of intersection SP.

The drive shaft 4 is designed at the drive flange end with a torque transmission means 12, for example a spline, for introducing a drive torque or for tapping a drive output torque.

The cylinder drum 7 is located to control the supply and discharge of pressure medium in the piston chambers formed by the piston recesses 8 and the piston 10 Verdrängerräumen V on a control surface 15 which is provided with not shown kidney-shaped control recesses, an inlet port 16 and an outlet port of Form axial piston 1. To connect the displacers V formed by the piston recesses 8 and the pistons 10 with the control recesses, the cylinder drum 7 is provided with a control opening 18 on each piston recess 8.

The axial piston machine 1 of FIG. 1 is designed as an adjusting machine with a variable displacer volume. In the adjusting machine is the Inclination angle α and thus the pivot angle of the rotation axis R _{z of} the cylinder drum 7 with respect to the rotation axis R _{t of} the drive shaft 4 for changing the displacer volume adjustable. The control surface 15 against which the cylinder drum 7 rests is formed for this purpose on a weighing body 19, which is arranged pivotably in the housing 2 about a pivot axis which lies at the point of intersection SP of the rotation axis R _{t of} the drive shaft 4 and the rotation axis R _{z of} the cylinder drum 7 and perpendicular to the axes of rotation R _t and R _{z is} arranged.

Depending on the position of the weighing body 19, the inclination angle α of the rotation axis R _{z of} the cylinder drum 7 changes to the rotation axis R _{t of} the drive shaft 4. The cylinder drum 7 can be pivoted into a zero position with a pivot angle 0 ° degree, in which the axis of rotation R _{z of} the cylinder drum coaxial with the axis of rotation R _{t of} the drive shaft 4 is. Starting from this zero position, the cylinder drum 7 can be pivoted to one or both sides, so that the axial piston of the FIG. 1 can be executed as unilaterally pivotable or as two-sided pivotable adjusting. A device for pivoting the weighing body 19 and thus the cylinder drum 7 is in the FIG. 1 not shown in detail.

The pistons 10 are each hinged to the drive flange 3. For this purpose, a ball joint 20 formed as a spherical joint is respectively formed between the respective piston 10 and the drive flange 3. The hinge 20 is - as in connection with the FIG. 2 is more apparent - is formed by a ball head 10a of the piston 10 and a spherical cap and thus hollow spherical receiving tray 3a in the cylinder drum 7 facing end face 3b of the drive flange 3, in which the piston 10 is fixed to the ball head 10a.

The pistons 10 may further each be provided with a piston 10 passing through the longitudinal bore 13, which is in communication with the displacement chamber V and extends through the ball head 10 b, to hydrostatically relieve the ball joint connection 20.

The pistons 10 each have a collar portion 10b, with which the piston 10 is arranged in the piston recess 8. A piston rod 10c of the piston 10 connects the collar portion 10b with the ball head 10b.

In order to allow a compensating movement of the piston 10 during a rotation of the cylinder drum 7, the collar portion 10b of the piston 10 is arranged with play in the piston recess 8. The collar portion 10b of the piston 10 may be designed to be spherical. For sealing the piston 10 with respect to the piston recesses 8, a sealing means 21, for example a piston ring, is arranged on the collar portion 10b of the piston 10.

For storage and centering of the cylinder drum 7, a spherical guide 25 is formed between the cylinder drum 7 and the drive flange 3 and the drive shaft 4. The spherical guide 25 is formed by a spherical portion 26 of the drive flange 3 and the drive shaft 4, on which the cylinder drum 7 is arranged with a hollow spherical portion 27. The center of the sections 26, 27 is located at the intersection SP of the axis of rotation R _{t of} the drive shaft 4 and the axis of rotation R _{z of} the cylinder drum 7. In the illustrated embodiment, the hollow spherical portion 26 is formed on the end face of a sleeve-like bushing 50 in a central longitudinal recess 11 of the cylinder drum 7 and thus arranged and fixed inside the cylinder drum 7.

In order to achieve a driving of the cylinder drum 7 in the operation of the axial piston machine 1, a driving device not shown is provided which couples the drive shaft 4 and the cylinder drum 7 in the direction of rotation, for example, a driving joint, which is preferably designed as a constant velocity joint.

In the axial piston machine 1 according to the invention in a bent-axis design are - as in the FIGS. 3 to 5 is shown in detail - the spherical cap-shaped receiving trays 3a each formed only as extending to the ball equator hemispheres. The centers M of the hemispherical ball-shaped receiving shells 3a are thus located in the plane defined by the end face 3b of the drive flange 3 level. The spherical cap-shaped receiving shells 3a designed as hemispheres thus wrap around the ball head 10a by 180 °. In the FIG. 3 Here is a plan view of the front side 3b of Triebflansches 3 shown in the region of a receiving tray 3a, wherein the corresponding piston 10 is not shown.

To positively secure the ball heads 10a of the pistons 10 in the hemispherical hollow receiving shells 3a, a retaining web 30 is formed on the end 3b of the drive flange 3 in the region of the receiving trays 3a, which - as in the FIG. 5 is shown - extends over the ball equator of the hemisphere to engage around the ball head 10b at an angle greater than 180 degrees and to wrap around. For this purpose, the retaining web 30 is provided on the inner contour with a ball contour 31 which continues the spherical contour of the spherical-cap-shaped receiving shells 3a.

The retaining web 30 forms on each receiving tray 3a each have two retaining portions 30a, 30b, which - as in the FIGS. 3 and 5 is visible - are arranged opposite to the receiving tray 3a and are each provided with the ball contour 31.

The retaining web 30 is formed by an annular, circumferential increase 32 on the end face 3b of the drive flange 3. The annular elevation 32 and thus the retaining web 30 is arranged concentrically to the rotation axis R _{t of} the drive flange 3, so that the center of the retaining web 30 forming annular elevation 32 on the axis of rotation R _{t of} the drive flange 3 is arranged.

The annular increase 32 is arranged on the end face 3b of the drive flange 3 in the region of a pitch circle diameter T _K , on which the centers M of the hemispherical receiving shells 3a are arranged.

The annular elevation 32 is thus arranged facing the cylinder drum 7 on the end face 3b of the drive flange 3.

The retaining web 30 has in the radial direction to a width B, which is significantly smaller than the diameter of the hemisphere, for example, at most 1/3 of the diameter of the hemisphere and thus the diameter of the ball head 10b. The radial Outer peripheral surface 30d of the retaining ridge 30 is spaced radially inward from the radial outer peripheral surface 3d of the driving flange 3.

In the illustrated embodiment, the retaining web 30 is integrally formed on the end face 3b of the drive flange 3. The contour of the drive flange 4 is thus provided with the retaining web 30 and thus the annular extension 32, which protrudes from the end face 3b. Preferably, the retaining web 30 is already formed on a blank of the drive flange 3 with a certain excess, so that the contour of the retaining web 30 can be produced in a cost-effective manner in a turning of the drive flange 3.

In the axial piston machine 1 according to the invention, the retention of the piston heads 10b in the hemispherical receiving shells 3a is restricted to the area of the retaining webs 30. Since the circumferential retaining ridge 30 is spaced radially inwardly from the radial outer peripheral surface 3d of the drive flange 3, a free space is created which makes it possible to bring the cylindrical drum 7 close to the end face 3a of the drive flange 3 with the end face 7a containing the piston outlet openings, so that in the axial direction of the longitudinal axis L compact dimensions of the axial piston machine 1 according to the invention are made possible. In the FIG. 2 is a possible, small distance s between the piston outlet openings containing end face 7a containing cylindrical drum 7 and the centers M of the hemispherical receiving shells 3a shown, which are arranged on the end face 3b of the drive flange. In order to achieve the shortest possible distance s, the cylinder drum 7 facing end face of the retaining ridge 30 is provided in the radially outer region with a chamfer 33 which is inclined to the end face 3b of the drive flange 3.

In order to introduce the piston 10 with the ball heads 10b in the receiving trays 3a, each ball head 10b - as in the FIG. 5 is illustrated - provided with two oppositely disposed grooves 40a, 40b. The grooves 40a, 40b are formed as executions of the spherical surface in the region of the equatorial region of the ball heads 10b. The distance D between the mutually parallel and cylindrical groove bottoms of the two grooves 40a, 40b is smaller than the opening width E between the two retaining portions 30a, 30b of the retaining web 30 on the respective receiving tray 3a.

The groove width F of the grooves 40a, 40b is - as in the FIG. 4 is illustrated - each greater than the width B of the retaining web 30th

The grooves 40 a, 40 b are arranged on the ball head 10 a with the longitudinal axis L _N inclined to the longitudinal axis L _{K of} the piston 10. In the illustrated embodiment, the longitudinal axis L _{N of} the grooves 40a, 40b with respect to the longitudinal axis L _{K of} the piston 10 at an angle forming a mounting angle β _M is arranged obliquely. The mounting angle β _M is less than 90 ° degrees.

In the Figures 1 to 11a the grooves 40a, 40b have a straight course.

The inclination angle β _{M of} the grooves 40a, 40b is designed such that the inclination angle β _M for mounting the pistons 10 is different from the maximum tilt angles β _{1 of} the pistons 10 occurring during operation of the axial piston machine 1.

For mounting the pistons 10 in the receiving trays 3a, a recess 45 for the piston rod 10c of the piston 10 is formed on the drive flange 3 on each receiving tray 3a. In the illustrated embodiment, the recesses 45 are formed on the radially outer portion of the receiving shells 3a in the end face 3b of the drive flange 3 and extend from the receiving tray 3a radially outward toward the radial outer peripheral surface 3d of the drive flange 3 extend. The recesses 45 are - seen in the radial direction inwardly - provided starting from the radial outer peripheral surface 3d with an increasing to the receiving tray 3a depth.

At the outer edge between the radial outer peripheral surface 3d and the end face 3b of the drive flange 3 is further provided with a chamfer 46. The recesses 45 extend into the region of the chamfer 46.

In the FIGS. 6a to 8d the assembly process of the piston 10 in the receiving trays 3a is shown in more detail. The indices "a" to "d" in the FIGS. 6a to 8d according to the same assembly conditions.

For mounting the piston 10 in the receiving tray 3a, the piston 10 is inserted under the mounting angle β _M in the receiving tray 3a, as in the FIGS. 6a . 7a, 8a is shown. Since the longitudinal axis L _{N of} the grooves 40a, 40b is arranged parallel to the retaining web 30 at the tilted at the mounting angle β _M piston 10, the hoop 10 with the two grooves 40a, 40b between the two retaining portions 30a, 30b of the retaining web 30 in the receiving tray 3a are introduced - as in the FIGS. 6b . 7b . 8b and 6c . 7c, 8c is shown. When fully inserted into the receiving tray 3a under the mounting angle β _M piston 10, the piston rod 10b comes into contact with the recess 45. If the ball head 10b was completely inserted into the receiving tray 3a, the piston 10 can be tilted back starting from the mounting angle β _m in the tilt angle β ₁ - as in the FIG. 6c by the arrow 60 and in the FIGS. 6d . 7d, 8d is shown -, so that the ball head 10b by means of the retaining web 30 is positively secured in the receiving tray 3a.

During operation of the axial piston machine 1, the piston 10 -as in FIGS FIGS. 6d and 9a to 9c shown - the maximum tilt angle β ₁ , so that the piston head 10b is securely secured in the receiving shells 3c during operation of the axial piston machine 1.

In the FIGS. 10a to 10c are perspective views of the secured in the receiving cup 3c piston 10 is shown.

In the FIG. 11b a second embodiment of a piston 10 is shown, in which the grooves 40a, 40b in the piston head 10b have a bent course. The grooves 40a, 40b have a first portion, which is arranged obliquely inclined to the longitudinal axis L _{K of} the piston 10 with the longitudinal axis L _N at the inclination angle β _M. A second section of the grooves 40a, 40b is further bent relative to the first section and arranged in the illustrated embodiment with the longitudinal axis L _N2 perpendicular to the longitudinal axis L _{K of} the piston 10. By the bent second portion of the grooves 40a, 40b is achieved that the ball end of the ball head 10b, which faces the piston shaft 10c, from the outer edge of the groove 40a, 40b has a dimension t2, compared to the dimension t1 a straight design of the grooves 40a , 40b, so that the load-bearing ball half, that of the piston rod 10c opposite and the piston forces in the receiving tray 3a is supported, having an enlarged area.

The invention has a number of advantages.

The inventive locking of the piston 10 in the receiving trays 3a has by the hemispherical receiving cups 3a and the retaining web 30 on the end face 3b of the drive flange 3, which protrudes from the end face 3b of the drive flange 3, a low manufacturing effort. In addition, a compact axial dimension of the axial piston according to the invention with the inventive locking of the piston 10 in the drive flange 3 can be achieved. Due to the two inclined grooves 40a, 40b, the locking of the piston 10 according to the invention for adjusting machines with an adjustable displacement volume is suitable and allows pivoting angle of 0 ° degrees. The two grooves 40a, 40b on the piston heads 10 lead to flattenings on the piston heads 10 to produce cylindrical surfaces, due to the small groove width F of the grooves 40a, 40b to a small reduction of the spherical surface on the load-bearing ball half, the piston rod 10c opposite.

The invention is not limited to the illustrated embodiments. The axial piston machine 1 according to the invention can alternatively be designed as a constant machine instead of as an adjusting machine. In a constant machine, the inclination angle α of the rotation axis R _{z of} the cylinder drum 7 with respect to the rotation axis R _{t of} the drive shaft 4 is constant and fixed. The control surface 15 against which the cylinder drum 7 rests can in this case be formed on the housing 2.

It is understood that the bushing 50 can be integrally formed on the cylinder drum 7.

The drive flange 3 can be designed as a separate from the drive shaft 4 component, which is connected to the drive shaft 4 torque.

The chamfer 46 on the drive flange 3 can be enlarged such that the additional recesses 45 for the assembly of the piston 10 can be omitted.

Claims (17)

Hydrostatic axial piston machine (1) in a bent-axis design with a about a rotational axis (R _t ) rotatably within a housing (2) arranged drive shaft (4), with a about an axis of rotation (R _t ) rotatably within the housing (2) arranged drive flange (3) , and with a about an axis of rotation (R _z ) rotatably within the housing (2) of the axial piston machine (1) arranged cylinder drum (7), wherein the cylinder drum (7) is provided with a plurality of Kolbenausnehmungen (8), in each of which a piston ( 10) is arranged to be longitudinally displaceable, wherein the pistons (10) are articulated to the drive flange (3) and for articulated attachment of the piston (10) to the drive flange (3) is provided in each case a ball joint connection (20) consisting of a kugelkalottenförmigen receiving tray (3a) in an end face (3b) of the drive flange (3) and a ball head (10b) is formed, which is in operative connection with the piston (10), characterized in that the receptacle Shells (3a) are each formed as extending to the Kugeläquator hemispheres and on a front side (3b) of the drive flange (3) in the receiving shells (3a) a retaining web (30) is formed, which extends over the ball equator of the hemisphere to surround the ball head (10b) at an angle greater than 180 degrees. Hydrostatic axial piston machine according to claim 1, characterized in that the retaining web (30) on each receiving tray (3a) respectively two retaining portions (30a, 30b) which are arranged opposite to the receiving tray (3a) and beyond the hemisphere. Hydrostatic axial piston machine according to claim 1 or 2, characterized in that the retaining web (30) by an annular elevation (32) on the end face (3b) of the drive flange (3) is formed. Hydrostatic axial piston machine according to one of claims 1 to 3, characterized in that the center of the retaining web (30) on the rotational axis (R _t ) of the drive flange (3) is arranged. Hydrostatic axial piston machine according to one of claims 1 to 4, characterized in that the retaining web (30) in the region of a pitch circle (T _k ) is arranged, on which the centers (M) of the hemispheres are arranged. Hydrostatic axial piston machine according to one of claims 1 to 5, characterized in that the retaining web (30) is integrally formed on the end face (3b) of the drive flange (3). Hydrostatic axial piston machine according to one of claims 1 to 6, characterized in that the ball head (10b) with two oppositely disposed grooves (40a, 40b) is provided, wherein the distance (D) between the groove bottom of the two grooves (40a, 40b) smaller as the opening width (E) of the two retaining portions (30a, 30b) on the respective receiving tray (3a). Hydrostatic axial piston machine according to claim 7, characterized in that the groove width (F) of the grooves (40a, 40b) is greater than the width (B) of the retaining web (30). Hydrostatic axial piston machine according to claim 6 or 7, characterized in that the grooves (40a, 40b) on the ball head (10b) obliquely inclined to the longitudinal axis (L _K ) of the piston (10) are arranged. Hydrostatic axial piston machine according to claim 9, characterized in that the angle of inclination (β _m ) of the grooves (40a, 40b) is designed such that the inclination angle (β _M ) of the tilting angles (β ₁ ) occurring during operation of the axial piston machine (1) Piston (10) is different. Hydrostatic axial piston machine according to one of claims 1 to 10, characterized in that on the drive flange (3) on each receiving tray (3a) has a recess (45) for a piston rod (10c) of the piston (10) is formed. Hydrostatic axial piston machine according to one of claims 1 to 11, characterized in that for guiding the cylinder drum (7) between the drive flange (3) and the cylinder drum (7) is formed a spherical guide (25). Hydrostatic axial piston machine according to claim 11 or 12, characterized in that the recesses (45) at the radially outer region of the receiving shells (3a) in the end face (3b) of the drive flange (3) are formed. Hydrostatic axial piston machine according to one of claims 11 to 13, characterized in that the drive flange (3) at the outer edge (3d) of the end face (3b) is provided with a chamfer (46) which is dimensioned such that the chamfer (46) the recess (45) for the piston rod (10c) of the piston (10). Hydrostatic axial piston machine according to one of claims 1 to 14, characterized in that the grooves (40a, 40b) have a straight course. Hydrostatic axial piston machine according to one of claims 1 to 14, characterized in that the grooves (40a, 40b) have a bent course. Hydrostatic axial piston machine according to claim 16, characterized in that the grooves (40a, 40b) have a first portion which is obliquely inclined to the longitudinal axis (L _K ) of the piston (10), and have a second portion, which is opposite to the first portion is bent, in particular perpendicular to the longitudinal axis (L _K ) of the piston (10) is arranged.

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