WO2020249682A1

WO2020249682A1 - Component of a piston machine and method for producing the component

Info

Publication number: WO2020249682A1
Application number: PCT/EP2020/066219
Authority: WO
Inventors: Stefan KOBEL; Rolf URBEN
Original assignee: Urben & Kyburz Ag
Priority date: 2019-06-12
Filing date: 2020-06-11
Publication date: 2020-12-17
Also published as: CH716310B1; CH716310A1

Abstract

The present invention relates to a component (20) for a piston machine, comprising a carrier body (22), made from a first material, having a first geometry formed on a surface (28), and comprising a sliding part (30) having a sliding bottom (6), made from a second material, wherein a second profile geometry is formed on a connection surface (38) which profile geometry can be integrally connected to the first profile geometry. The invention also relates to a production method for the component (20).

Description

Component of a piston engine and

Process for manufacturing the component

Technical field of the invention

The invention relates to a component of a piston machine and a method for producing the component. This is specifically a component with a carrier body and a sliding part for a hydrostatic or hydraulic axial piston pump or axial piston motor, in particular a multi-part sliding shoe with a sliding shoe body and a sliding part, which are made from different materials.

State of the art

From the use in hydrostatic or hydraulic axial piston machines in swash plate design, components are known which are designed as sliding shoes. Accordingly, axial piston machines have components which include cylinder pistons movably received in cylinder bores, which are supported by means of a sliding shoe on a sliding surface of a swash plate. The cylinder piston is generally articulated to the sliding shoe by means of a ball-and-socket joint connection in order to enable a flat contact of a circular sliding block of the sliding shoe on the sliding surface of the swashplate in every inclined position of the swashplate. The ball joint connection comprises a ball head formed on the slide shoe or on the cylinder piston, which can be inserted in a rounded recess on the corresponding counterpart, or is positively anchored in this, so that tensile forces can be transmitted during the stroke of the piston machine . Accordingly, the ball head can be formed on the cylinder piston or on the slide shoe.

In the case of a sliding shoe, to reduce the friction in the ball-and-socket joint connection between this and a cylinder piston, ie between the spherical joint head and the spherical recess, a corresponding Speaking trained lubricating oil bore provided through which the contact surface between the component designed as a sliding block and the cylinder piston is supplied with lubricant. A through-hole is also provided on the component, which is designed as a sliding shoe, which transports the lubricant to the sliding base of the sliding part.

Components such as Sliding shoes in piston machines must meet high requirements in terms of fatigue strength and mechanical properties, so that they have a long service life when used in hydraulic or hydrostatic piston machines. Materials suitable for this, however, often do not meet the likewise high requirements with regard to the sliding properties for a sliding surface on the sliding part and vice versa, so that the choice of material often follows a compromise.

Accordingly, a multi-part sliding shoe for a hydrostatic or hydraulic piston machine is known, which consists of a sliding shoe body or support body and a sliding part with a sliding sole that slides on a kor respondierenden running surface. So-called bimetallic sliding pieces are known in which a suitable material for the sliding surface, in particular bronze, is sintered or cast onto a support body made of steel, the manufacturing costs being correspondingly high. According to conventional methods, these layers and / or layers are applied to the carrier body, preferably made of steel, by casting, sintering, brazing and / or welding, and then heat-treated.

Document DE 2 025 169 A1 describes a sliding shoe made from different materials, in which a sliding part and a support body are firmly connected to one another by an adhesive process, for example casting, melting, gluing, soldering or spraying. Different thermal expansion of the materials used is taken into account when shaping the sliding shoe. However, the material pairing also corresponds to a compromise, due to the adhesive connection. Furthermore, a faultless production of a sliding shoe according to the prior art is very costly and difficult. Complex quality controls of the manufactured sliding blocks are required, in which, for example, each sliding shoe is subjected to an ultrasonic test. High rejection rates drive manufacturing costs up further.

In addition, the heat influence occurring in the known manufacturing process and the resulting change in the composition, structure and physical properties of the material of the sliding part proves to be problematic. The object of the present invention is therefore to provide a component for a piston machine which has suitable materials for both a sliding surface and a carrier body and can be manufactured economically in a cost-effective and quality-optimized manufacturing process. The tasks are with the inventive component with the

Features of claim 1 and solved with the method according to the invention according to claim 12.

Summary of the Invention The present invention relates to a component for a piston engine, e.g. a hydrostatic or hydraulic axial piston pump and / or a corresponding motor. Components within the meaning of the invention include, in particular, a slide shoe, a control disk and / or a cylinder drum of an axial piston machine, although the list is not to be understood as limiting.

A component according to the invention comprises a carrier body, made of a first material, with a first profile geometry formed on one surface, and a sliding part with a sliding sole, made of a second material, with a second profile geometry on a connecting surface is formed, which is positively connectable to the first profile geometry of the support body.

The component according to the invention for a piston machine is designed in several parts, the first and the second material having to meet different functional requirements, i.e. the first material of the carrier body must have different properties than those of the second material of the sliding part. Since the support body is generally in contact with other elements of the piston machine, for example in the case of a sliding shoe in contact with a cylinder piston by means of a ball head connection, high demands are placed on the material of the support body with regard to good machining, corresponding to dimensionally accurate shapes. A suitable and in particular easily machinable material is steel or ferrous metal.

Furthermore, with a suitable choice of the material of the carrier body, it can be machined before pairing with the sliding part in order to preferably increase the flake conditions on the paired profile geometries. The area of the first profile geometry can be processed by means of compressed air blasting with solid blasting media such as sand or balls. Furthermore, the carrier body, especially in the area of the first profile geometry, can be processed by means of a surface hardening process, such as gas nitriding or gas nitrocarburizing, and / or a thermal hardening process and thus surface properties can be specifically adjusted to increase the frictional force in the area of the form-fitting connection to achieve. With a suitable choice of the temperature and the temperature profile, as well as the duration of the thermal hardening process, the properties of the carrier body can be changed individually independently of the sliding part. The pairing of the carrier body with the sliding part can then take place according to the further processing method, in which case, in particular, unfavorable thermal changes in the material of the sliding part and the associated deterioration in the sliding properties of the sliding sole are avoided.

It has proven to be advantageous that the carrier body can be shaped and machined independently of the sliding part. In particular is the production of the support body, for example the shoe body, from a Stan gene material by turning, from a forging blank by forging or from a stamped blank by punching simplified and cost-saving by feasible. Likewise, the completion of the contour, including grinding and polishing, and further steps for shaping the carrier body can be carried out independently of the sliding part and thus in an optimized manner.

The sliding part with the sliding sole is made of a material which is “self-lubricating” and sufficiently resistant to seizure, as well as showing high wear resistance. So-called non-ferrous metals and corresponding alloys such as brass, bronze and gunmetal, as well as ceramics and flart metals, are particularly suitable as material. The second material can be special brass with a proportion of aluminum and manganese as well as other components, for example lead. Thus, a particularly low-friction sliding contact can be generated on running surfaces. According to the invention, the carrier body and sliding part are connected to the component by means of a form-fitting connection, e.g. a sliding shoe, control disk or the like, assembled. This has the advantage that a form-fitting connection replaces the cohesive pairing previously generally provided. The form fit, for example, avoids a soldering process or another material-locking process for producing a material-locking or material-locking connection, and therefore not only a costly, but also a work step that is problematic due to the influence of heat.

In order to create a secure and resilient positive connection between the carrier body and the sliding part, according to a preferred embodiment of the invention, the first profile geometry is formed on the surfaces to be paired on the carrier body and the second profile geometry is formed on the sliding part. Accordingly, the first profile geometry and the second profile geometry can be designed to be complementary and thus have a male or female profile, for example elevations and depressions. Preferably, said profile geometries are circular, concentric around one Grooves running along the longitudinal axis, which are at least partially feasible into one another. In addition, first and second profile geometries can have structured areas which can be connected in a materially bonded manner.

When joining the carrier body and sliding part of the component, e.g. of the sliding shoe body and sliding part, the formed profile geometries are pressed into one another. It is provided that elevations and / or depressions with a defined first profile geometry are formed on the surface to be joined on the carrier body, preferably as grooves arranged along circular lines, centered around the longitudinal axis of the component. In a preferred embodiment, the flanks delimiting the grooves are designed conically, i.e. with respect to the longitudinal axis inclined at an angle extending, so that the groove is trapezoidal.

In a further embodiment, the first profile geometry formed on the support body has a plurality of concentric, circular grooves which differ in terms of arrangement and shape. With several grooves, the flanks cannot be inclined and / or inclined differently. The complementary mating surfaces of the second profile geometry of the sliding part of the component are designed accordingly. When the support body, in particular made of steel, and the sliding part, in particular made of brass, are joined together, the shapes and surfaces to be paired are pressed onto or into one another, whereby the inclined flanks, i.e. the conical shape of the grooves that are formed, the protrusions and depressions pressed into one another in the profile geometries are kept in intimate contact by means of frictional force in the area of the flanks by means of self-locking. Dome-shaped, radial and / or parallel elevations and depressions can also be considered as profile geometries. In addition, a step in the form of a flange can be formed on the support body and / or sliding part on the outer circumference, which is undercut and into which the counterpart formed with complementary elevations is pressed during the pressing process in such a way that a further form-fitting connection is also formed.

The second profile geometry on the sliding part can differ from the first profile geometry of the support body, but only to the extent that that the profile geometries can be pressed into one another in order to create a form-fitting and possibly an additional material connection. When the profile geometries are pressed, cold forming takes place in defined areas with a material bond, so that additional clawing of the carrier body and sliding part is achieved.

In another embodiment the sliding part of the component of a piston engine, e.g. the sliding shoe, on the sliding sole, which is in contact with a sliding surface, also concentric to the longitudinal axis of the sliding shoe, relief grooves that provide relief in the area of the sliding sole when slidingly supported on a sliding surface. The relief grooves are preferably formed on a surface of the sliding sole opposite the second profile geometry in an arrangement that a remaining wall thickness between the second profile geometry and the relief grooves is largely constant. The pairing of different materials by means of a pressing process of complementarily designed shapes and surfaces to form a multi-part component for a piston machine can, for example, be used for a slide shoe, a control disk and / or a cylinder drum. For example, a control disk of a hydraulic or hydrostatic axial piston pump, also referred to as a control base or control mirror, comprises a support body, for example made of steel, and a sliding part designed as a running layer, e.g. in the form of a non-ferrous metal disc. Here, too, the two parts are joined together by pressing projections and depressions formed in a defined manner on surfaces to be paired, the arrangement of elevations and depressions being coordinated with one another in such a way that the control disk produced does not have any thin-walled weak points, in particular in the area of kidney-shaped areas formed on it Recesses.

Furthermore, the present invention also relates to a method for producing a component of a hydraulic or hydrostatic piston machine, comprising providing a carrier body made from a first material and having a first profile geometry on a surface and a sliding part made of a second material and having a second profile geometry on a connecting surface which can be at least partially introduced into the first profile geometry. The carrier body and the sliding part are then joined together by means of a pressing process, the first profile geometry and the second profile geometry forming a positive connection.

Preferably, the first profile geometry and the second profile geometry form a material bond during the pressing process by means of cold forming. The method according to the invention also includes that the carrier body and / or the sliding part are processed independently of one another before the pressing process. For this purpose, the carrier body formed with the first profile geometry can be subjected to at least one processing step, which is a coating, a surface hardening process and / or compressed air blasting with solid blasting media.

The assembled component can also be processed using mechanical processing methods.

Brief description of the drawings Preferred embodiments of the component according to the invention of a piston machine are shown in the drawings and are described in more detail with reference to the following description. Show it:

1 a, 1 b show schematic sectional views of a joint connection between a cylinder piston and a component of an axial piston machine designed as a sliding shoe;

FIG. 2 shows a schematic sectional illustration of a component for use in a hydrostatic axial piston machine; FIG. 3 shows a schematic sectional illustration of a component for use in an axial piston machine in a second embodiment;

FIG. 4 shows a schematic sectional illustration of a carrier body and a sliding part as elements of a component of an axial piston machine before they are joined;

FIG. 5a shows a schematic sectional illustration of a carrier body in a further embodiment and a sliding part during the joining;

FIG. 5b shows a detailed view of a joint of the joined parts according to FIG. 5a; and

FIG. 6 shows a schematic sectional illustration of a control disk for a piston pump.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION The articulated connections 1 shown in FIGS. 1 a and 1 b are designed to connect two elements to one another in a space-articulated manner so that the elements can be pivoted on all sides relative to one another. In the illustrated embodiment, the articulated connection 1 is formed between a cylinder piston 2 of an axial piston machine and a sliding shoe 3. The axial piston machine is designed, for example, in a swash plate design, with a cylinder drum rotatably mounted in a housing with a plurality of axial cylinder piston receptacles distributed around the circumference with cylinder piston 2 slidably received therein and with the sliding shoe 3 resting on a sliding surface formed on a swash plate. is based.

On the sliding shoe 3, a flat sliding sole 6 is formed, which when the cylinder drum of the axial piston machine rotates along a Circular path slides on the sliding surface of the swash plate. At the end of the cylinder piston 2 facing away from the Ge joint 1, a cylinder opening is provided through which, during a pressure stroke of a stroke movement, pressure medium is pressed from a cylinder bore into a control kidney of a control disk and passed on from there via a working line. Here, during the pressure stroke of the shoe 3 due to the pressure prevailing in the cylinder bore tion in contact with the sliding surface of the swashplate keep ge. The contact of the sliding sole 6 on the sliding surface of the swash plate is also ensured by devices during a suction stroke, which are not explained in detail here.

The articulated connection 1 has a ball head 10 on one element and a recess 12 on the other element. In Fig. 1a, the ball head 10 is formed on the sliding shoe 3 and received in the recess 12, formed on the cylinder piston 2, the ball head 10 being pivotably mounted in the recess 12 on all sides and overlapping from an edge area of the recess 12 and is thus positively received therein. Accordingly, both tensile and compressive forces can be transmitted between the cylinder piston 2 and the slide shoe 3. In the Ausfüh approximately example of Fig. 1a, the ball head 10 is connected by a neck 18 to the sliding block 3, preferably formed in one piece thereon.

To reduce the friction between the ball head 10 and the recess 12, a lubricating oil bore 14 is seen in the cylinder piston 2, through which the contact surface between the shoe 3 and cylinder piston 2 is supplied with lubricant. Furthermore, a through-hole 16 is provided on the sliding shoe 3, which transports the lubricant to the sliding sole 6 of the sliding shoe 3.

Fig. 1 b shows another embodiment of the invention, in wel chem identical or comparable parts are denoted by the same reference numerals, and wherein the ball head 10 is connected through the neck 18 to the cylinder piston 2, preferably integrally formed thereon. In FIG. 2, a first exemplary embodiment of a component 20 according to the invention is shown, which is designed as a slide shoe 3. The construction part 20 is penetrated by the lubricating oil bore 16 extending along a longitudinal axis 26. In order to connect the sliding shoe 3 in an articulated manner to a further element of a piston machine, the spherical head 10 is formed on a carrier body 22 of the component 20 designed as sliding shoe 3. At an end facing away from the spherical head 10, a carrier body foot 24, also referred to as a sliding shoe foot, is formed on the carrier body 22 and is widened in the radial direction. The carrier body 22 extends axially along the longitudinal axis 26, a circular surface 28 being provided on the carrier body foot 24 at the end of the carrier body 22 opposite the spherical head 10. The surface 28 provides a contact surface for a sliding part 30 to be connected to the carrier body 22. For this purpose, it is provided according to the invention that one or preferably a plurality of annular grooves 32 arranged concentrically around the longitudinal axis 26 are formed on the surface 28. The surface 28 accordingly has a first profile geometry, formed by grooves 32 or by depressions and / or elevations.

The plurality of circular grooves 32 can be designed identically or differently with regard to a groove depth 34, and can be distributed uniformly or irregularly. Furthermore, the respective groove 32 is delimited by flanks 36, which are parallel or angled to the longitudinal axis 26, ie run at angles CM, 02, which can be different, so that the respective groove 32 largely has a trapezoidal shape . The angles CM, 02 can differ within the first profile geometry. To complement the component 20 of a piston engine, the carrier body 22 is connected to the sliding part 30 and the sliding sole 6 formed thereon so that the sliding part 30 can be positively fixed with a connection surface 38 on the surface 28 formed with the first profile geometry. Accordingly, the connecting surface 38 of the sliding part 30, which is embodied in the form of a disk, also has a second profile geometry that is complementary to the profile geometry of the surface 28, with elevations and / or depressions, preferably one or more circular grooves 40, which are formed with the grooves 32 on the Surface 28 engaged and can be pressed together. In the case of trapezoidal grooves 32, 40, depending on the choice of the flank angles CM, Ö2, self-locking of the pairing can be achieved through friction, which connects the joined parts firmly to one another.

Provision is made for the carrier body 22 to be made of the material steel and, in particular, to have been processed prior to being joined to the sliding part 30. The sliding part 30 itself can be made as a circular disk made of non-ferrous metal.

3 shows a further embodiment of a component 20 formed as a slide shoe 3, in which the same or similar parts are identified by the same reference numerals. The component 20 comprises the carrier body 22 and the sliding part 30, which are fitted into one another, so that the complementary profile geometries formed in each case on contact surfaces 28, 38 mesh with one another. On the sliding sole 6 of the sliding part 30 opposite the connecting surface 38, one or more circular relief grooves 50 are provided in the illustrated embodiment, which provide relief for the pairing of sliding sole 6 and sliding surface of the swash plate. In order to ensure that there is no material weakening in the area of the sliding part 30, the arrangement of the relief grooves 50 on the sliding sole 6 is offset to the arrangement of the grooves 40 on the opposite side, i.e. the connecting surface 38 of the sliding part 30 forms out.

In Fig. 4, support body 22 and sliding part 30, which add together to form the component 20 according to the invention, are shown separately, ie before pressing in one another. In the embodiment shown, the profile geometry formed on the surface 28 is configured differently from the profile geometry of the connecting surface 38. In particular, the shape and orientation of the depressions / elevations relative to the longitudinal axis 26 of the grooves 32 of the surface 28 differ from one another and these in turn differ from the grooves 40 which are formed on the connecting surface 38 of the sliding part 30. Grooves 32 are parallel to the longitudinal axis 26, inclined towards or away, the profile geometry comprising differently oriented grooves. On the other hand, on the connecting surface 38 of the sliding part 30, the grooves 40 can be none or one opposite the Orientation of the grooves 32 have a different inclination. Accordingly, during a pressing process of the parts to be joined, the carrier body 22 and the sliding part 30, there is not only a form-fitting connection of the profile geometries formed but also a material connection through cold forming of the profile geometries of the carrier body 22 and the sliding part 30, which are joined together.

In Fig. 5a a further variant of the profile geometry is shown on the surface 28 of the support body 22 and / or the connecting surface 38 of the sliding part 30, it also being evident that the parts to be joined are received in a pressing device comprising punch 42 and die 44 Here, an undercut step 48 with an inclined delimiting flank 50 is formed on an outer circumference 46 of the carrier body 22. During the pressing process, the outer ring-shaped elevation of the profile geometry of the sliding part 30 is pressed into the undercut step 48, a material connection being produced in this area of the parts to be joined by cold forming.

5b shows a detail of the parts pressed into one another, carrier body 22 and sliding part 30, it being evident that one of the grooves 40 of the sliding part 30 is pressed into the undercut step 48 on the outer circumference 46 of the carrier body and forms a material connection. The component 20 according to the invention can, however, also be another element of a piston machine, in particular an axial piston machine. FIG. 6 shows a sectional illustration of a control disk 60 which, as described above, is also a component 20 in a hydrostatic or hydraulic axial piston pump. The control disk 60 comprises the carrier body 22, to which a sliding part 30 can be firmly connected. Here, too, defined profile geometries are formed on the contact surfaces to be joined, which are pressed into one another during a pressing process and possibly, in addition to a form fit, can be materially connected. In particular, the profile geometries are designed in such a way that there are no thin-walled areas of the control disk 60, in particular in the vicinity of control kidneys 62 formed thereon.

Claims

1. Component (20) for a piston engine, comprising

- A support body (22), made of a first material, with a first profile geometry formed on a surface (28), and - a sliding part (30) with a sliding sole (6), made of a second

Material, with a second profile geometry being formed on a connection surface (38), which can be positively connected to the first profile geometry.

2. Component (20) according to claim 1, characterized in that the first material of the carrier body (22) is selected from the group comprising steel and ferrous metal and the second material of the sliding part (30) is selected from the group comprising Non-ferrous metals, their alloys, ceramics and hard metals.

3. Component (20) according to claim 1 or 2, characterized in that the first profile geometry and the second profile geometry are designed in such a way that they can be materially connected in structured areas.

4. Component (20) according to one of the preceding claims, characterized in that the first profile geometry and the second profile geometry each have at least one groove (32, 40) which runs concentrically around a longitudinal axis (26) and which can be at least partially inserted into one another.

5. Component (20) according to claim 4, characterized in that the grooves (32, 40) are trapezoidal, the grooves (32, 40) limiting flanks (36) relative to the longitudinal axis (26) at an angle (CM , 02) are inclined.

6. Component (20) according to claim 5, characterized in that the first profile geometry and / or the second profile geometry comprise a plurality of grooves (32, 40) which differ in terms of arrangement and shape.

7. Component (20) according to one of the preceding claims, characterized in that on the sliding part (30) on the sliding sole (6) relief grooves (50) are formed in an arrangement so that a remaining wall thickness between the second profile geometry and the Relief grooves (50) is largely constant.

8. Component (20) according to one of the preceding claims, characterized in that the component (20) is designed as a sliding shoe (3), as a control disc (60) and / or cylinder drum for an axial piston machine.

9. Component (20) according to one of the preceding claims, characterized in that the first profile geometry on the support body (22) by means

Compressed air blasting is processed with solid abrasive.

10. Component (20) according to one of the preceding claims, characterized in that the carrier body (22) with the first profile geometry formed thereon is hardened by means of a hardening process.

1 1. Component (20) according to one of the preceding claims, characterized in that the support body (22) is coated in the region of the first profile geometry.

12. A method for producing a component (20) for a piston machine according to any one of the preceding claims 1 to 1 1, comprising: a) providing a carrier body (22) made from a first

Material and having a first profile geometry on a surface (28); b) providing a sliding part (30) made of a second material and having a second profile geometry on a connecting surface (38) which can be at least partially inserted into the first profile geometry, and c) joining the support body (22) and sliding part (30) ) by means of a pressing process, the first profile geometry and the second profile geometry forming a positive connection.

13. The method according to claim 12, characterized in that in step c) the first profile geometry and the second profile geometry form a material connection during the pressing process by means of cold forming.

14. The method according to claim 12 or 13, characterized in that after step a) the shaped carrier body (22) is subjected to at least one processing step which is a coating, a surface hardening process and / or compressed air blasting with solid blasting media.

15. The method according to any one of claims 12 to 14, characterized in that following step c) the assembled component (20) is processed by means of mechanical processing methods.