EP1287232B1 - Axial piston engine - Google Patents

Description

The invention relates to an axial piston machine according to the preamble of claim 1.

An axial piston machine of this type is described in DE 32 22 210 A1.

In axial piston machines, it is known to use the housing interior as an intermediate collecting container for leakage fluid. During functional operation of the axial piston machine, a certain amount of leakage oil accumulates in the interior of the housing, which is under a low pressure and flows through a discharge gap or a discharge channel to a tank. The leakage fluid in the housing interior can serve for the lubrication of moving parts of the axial piston machine. It is also advantageous if the leakage fluid is present as a film between the contact surfaces of non-relatively moving parts, whereby contact corrosion and abrasion resulting from vibrations are avoided or at least reduced. It is also advantageous if the hydraulic fluid can reach the desired lubrication points as unhindered as possible. This is not guaranteed if there is a barrier in the housing interior, which prevents a desired supply of the fluid to the lubrication point. Such a barrier forms a multi-tooth coupling between two parts of the axial piston machine in the housing interior. The purpose of a multi-tooth clutch is to connect two parts rigidly, for. B. against a relative rotation to each other. Such a multi-tooth clutch can be provided in the axial piston machine of the type specified between a drive shaft and a cylinder drum mounted thereon. Since a multi-tooth clutch should transmit considerable coupling forces, one is strives to form the adjacent surfaces of the multi-tooth clutch not only in the region of the flanks of the teeth and the tooth gaps so that they are largely close together. As a result, the multi-tooth coupling forms a liquid barrier, which prevents or at least reduces the access of the hydraulic fluid to both sides of the multi-tooth clutch.

It is also known from the aforementioned DE 32 22 210 A1, a positioned on the drive shaft support ring with a ball-shaped support surface for a retaining plate for retaining sliding shoes by the periphery of the drive shaft opposing and axially arranged pressure pins to position in the working position, wherein the pressure pins are slidingly mounted in bores, which extend in the region of the multi-tooth coupling between the support ring on one side of the multi-tooth clutch and a pressure ring on the other side of the multi-tooth clutch. The pressure ring is biased by a compression spring against the pressure pins and against the support ring, wherein the pressure ring facing away from the end of the compression spring elastically biases the cylinder drum against a control disc. Also in this embodiment, the multi-tooth coupling forms a barrier which prevents the fluid from flowing from one side to the other side of the multi-tooth coupling. This is particularly problematic in the known embodiment because the fluid is prevented from flowing into a ring clearance between the drive shaft and the cylinder drum. An arranged in the region of a control disc bearings for pivotal mounting of the drive shaft to the respective housing wall is thereby separated from an intensive flow, lubrication and cooling of the hydraulic fluid.

In addition, the toothing is weakened when the holes for the pressure pins extend through the middle of the teeth or in the area of a pressure pin a tooth is omitted.

In DE 198 28 429 A1 an axial piston machine is described with a retraction device similar to the above retraction device with pressure pins. In this previously known embodiment, three pressure pins distributed around the circumference are displaceably mounted in each case in a first feedthrough channel, which is arranged in the foot region of a missing tooth of the cylinder drum. In this non-generic embodiment, the missing teeth form second passageways for the fluid. Also in this embodiment, the stability or strength of the toothed ring coupling is impaired because of the absence of teeth.

The invention has the object of providing an axial piston machine of the type described in such a way that while ensuring a stable configuration, the multi-tooth coupling allows a flow passage and / or a mechanical implementation of the one side to the other side of the multi-tooth clutch.

This object is solved by the features of claim 1. Advantageous developments of the invention are described in the subclaims.

In the embodiment according to the invention, a fluid flow through the passage channel from one side to the other side of the multi-tooth coupling is possible, so that in the functional operation, the fluid passes to both sides of the multi-tooth coupling and lubrication is ensured in these areas. Since the at least one feedthrough channel according to the invention is arranged in a tooth head surface and / or in an opposite tooth space base area, it is located in a region which is insensitive to weakening and the flanks of the teeth or tooth gaps are unimpaired.

Since the main load zone of the multi-tooth clutch is in the region of the flanks, the invention leads Design thus neither to a significant weakening of the cross section of the teeth nor to a reduction in the surface pressure. The stability and life of the multi-tooth clutch thus remains despite the presence of one or more distributed on the circumference arranged through channels.

It is advantageous for flow reasons to arrange several feedthrough channels preferably distributed uniformly over the circumference of the toothing. It is also possible to arrange the feed-through channel only in one of the opposing tooth head surface and tooth space base surface or opposite one another in both surfaces. The latter leads to a common feed-through channel of enlarged cross-section.

The cross-sectional shape of the at least one feedthrough channel can be different and adapted to structural conditions. A rounded or semicircular or U-shaped cross-sectional shape is advantageous in order to avoid a notch effect. However, the cross-sectional shape can also be square or hollow wedge-shaped, which is advantageous for manufacturing reasons and reasons mentioned below.

However, the inventive at least one feedthrough channel can also serve to receive a pin as part of the axial piston machine, for. B. a pre-described pressure pin which extends between two arranged on both sides of the multi-tooth clutch and axially movable components, for. B. between a compression spring and a support ring for a retraction device. The pressure pin extends through the feedthrough channel and can, for. B. be performed in a sliding motion with little movement. In this case, the feedthrough channel does not serve to provide flow communication between both sides of the spline coupling, but serves to provide a mechanical passage extending through the passageway To allow connection, and without significantly affecting the stability of the teeth.

In this case, the pin can be slidably guided in the passage channel with little play, so that a fluid passage is not present. If the at least one passage channel is formed with a sufficiently larger cross-section than the pin, then the embodiment according to the invention can form a passage for both the mechanical connection and for the fluid.

The feedthrough channel is open towards the tooth head surface or tooth space base. The advantage of this embodiment is that the at least one feedthrough channel can be produced as a simple and inexpensive groove, z. As by a machining with a collision tool, a broaching tool, a rolling hammer tool or a milling tool, especially when incorporating the profile in the cutter geometry.

Fig. 1

eine erfindungsgemäße Axialkolbenmaschine im axialen Schnitt;

Fig. 2

den Teilschnitt II-II in Fig. 1 mit mehreren abgewandelten Ausgestaltungen;

Fig. 3

einen dem Teilschnitt entsprechenden Schnitt in weiter abgewandelter Ausgestaltung;

Fig. 4

eine erfindungsgemäße Axialkolbenmaschine im axialen Schnitt in weiter abgewandelter Ausgestaltung;

Fig. 5

den Teilschnitt V-V in Fig. 4;

Fig. 6

einen dem Teilschnitt V-V entsprechenden Schnitt in abgewandelten Ausgestaltungen und

Fig. 7

einen dem Teilschnitt V-V entsprechenden Schnitt in weiter abgewandelten Ausgestaltungen.

The invention and further achievable by them advantages are explained in more detail with reference to preferred embodiments of an advantageous embodiment. Show it:

Fig. 1

an axial piston according to the invention in axial section;

Fig. 2

the partial section II-II in Figure 1 with a plurality of modified embodiments.

Fig. 3

a section corresponding to the section in a further modified embodiment;

Fig. 4

an axial piston according to the invention in axial section in a further modified embodiment;

Fig. 5

the partial section VV in Fig. 4;

Fig. 6

a section corresponding to the partial section VV in modified embodiments and

Fig. 7

a section corresponding to the partial section VV in further modified embodiments.

The axial piston machine 1 shown by way of example has a closed housing 2 with a cup-shaped housing part 3, the housing interior 4 is detachably closed by a so-called connector part 5, which is screwed in the sense of a cover at the free edge of the housing part 3 by suggestively illustrated screws 6. In the housing 2, a drive shaft 7 is rotatably mounted, which passes through the bottom wall 3a of the cup-shaped housing 3 in a bearing hole 8 and by rolling bearings 9, 11 directly or indirectly rotatably mounted on the bottom wall 3a of the cup-shaped housing 3 and the connecting part 5. On the inside of the connecting part 5 is a control disk 13 with approximately parallel to the axis of rotation 7a of the drive shaft 7 oppositely extending control channels 14, which are each connected to a supply line 15 and a discharge line 16 in the connection part 5, respectively. On the inside of the control disk 13 is located on a cylinder drum 17, which sits with a longitudinal hole 18 on the drive shaft 7 and thus rotatably connected by a multi-tooth clutch 19, in the present embodiment, only in one of the control disk 13 end portion facing away from the cylinder drum 17 and a this radially adjacent longitudinal region of the drive shaft 7 is arranged.

In the cylinder drum 17 are distributed around the circumference a plurality of axially parallel piston bores 21 are arranged, which are connected at their ends facing the control channels 14 by tapered supply and discharge channels 22 to the control channels 14 and on the control disc 13 side facing away from the Cylinder drum 17 open. In the piston bores 21, pistons 23 are mounted so as to be displaceable axially back and forth, which, with their ends facing the control disk 13, limit working chambers 24 in the piston bores 21 and protrude from the cylinder drum 17 with their head ends facing away from the control disk 13 and by means of support joints 25, in particular ball joints, are axially supported in a sloping transverse plane on a swash plate 26. In a present axial piston machine 1 in swash plate design, the swash plate 26 is formed by a so-called swash plate which is rigidly mounted in an axial piston 1 fixed throughput volume and an axial piston 1 variable throughput volume about a perpendicular to the axis of rotation 7a extending pivot axis 27 pivotally and by a per se known and not shown adjustment is adjustable and lockable in the set position. For this purpose, hollow cylinder portion-shaped bearing surfaces 31a serve on the swash plate and a pivot bearing. The swashplate has, on its side facing the cylinder drum 17, an inclined surface 26a on which the pistons 23 are supported by means of sliding shoes 29, which are pivotably connected on all sides by the support joints 25 to the head ends of the pistons 23.

In the present embodiment, the swash plate 26 is mounted on the bottom wall 3a, for which purpose a bearing ring 31 may be provided, which is supported on the bottom wall 3a and has a bearing hole in which the associated roller bearing 9 is mounted. In the swash plate 26, an axial through hole is arranged, through which the drive shaft 7 extends with clearance.

In functional operation of the axial piston machine 1, the drive shaft 7 and the cylinder drum 17 rotate together about the axis of rotation 7a, the piston due to the inclined plane on the swash plate 26, here on the inclined surface 26a, in the piston bores 21 are moved back and forth. In this case, the axial piston machine 1 can operate in pump operation or in engine operation. In order to prevent lifting of the shoes 29 from the inclined surface 26a, the shoes 29 is associated with a retraction device 33 which holds the shoes 29 in abutment with the inclined surface 26a and is formed in the present embodiment by a retracting disc 33, with the edge edges 35 flanges 29a the sliding blocks 29 engages behind in a conventional manner. The return pulley 33 is axially supported with a spherical-zone-shaped concave bearing surface 37 on a corresponding ball-zone-shaped convex bearing surface 38 on a support ring 39, which is mounted with a bearing hole 41 axially displaceable on the drive shaft 7 and is supported in the direction of the cylinder drum 17 with a force, which is greater than the lift-off forces. The support ring 39 is preferably non-rotatably connected by a second multi-tooth clutch 19a with the drive shaft 7, wherein the teeth 43a provided in common for both multi-tooth clutches and can be correspondingly long.

In order to achieve a good seal between the cylinder drum 17 and the control disk 13, it is advantageous to bias the cylinder drum 17 with an axial elastic force against the control disk 13. In the embodiment of FIG. 1 17 pressure forces are generated by a common axially effective spring 42 for the sliding shoes 29 and the cylinder drum, the z. B. between the support ring 39 and the cylinder drum 17 may be arranged and presses these parts apart.

2, the multi-tooth clutch 19 consists of a plurality of teeth 43a, 44a and tooth gaps 43b, 44b arranged on the lateral surface of the drive shaft 7 or on the inner lateral surface of the cylinder drum 13 and each in the circumferential direction whose main shape and size are each designed so that the teeth Fill out tooth spaces substantially. When the rotational drive in functional operation, the teeth are each loaded in the circumferential direction, wherein effective compressive forces are transmitted in the circumferential direction, which produce a certain surface pressure on the teeth 43a, 44a delimiting tooth flanks 43c, 44c. The surfaces extending between the flanks 43c, 44c are designated with head surfaces 43d, 44d and tooth space base surfaces 43e, 44e.

Due to the shape described so far forms the multi-tooth clutch 19 due to the relatively dense system a barrier wall or barrier, which prevents flow of the fluid between the arranged on both sides of the multi-tooth clutch 19 interior sections 4a, 4b. In order to permit a flow and thus a fluid exchange between the interior sections 4a, 4b, the toothing preferably has a passage channel 45 centrally in at least one tooth head surface 43d, 44d and / or in at least one tooth space base 43e, 44e of the drive shaft 7 and / or the cylinder drum 17 on, thus connecting the two interior sections 4a, 4b with each other, so that a flow can take place. As a result, the lubrication respectively associated surfaces are improved and prevents wear, abrasion and contact corrosion, or at least reduced. When an indoor section 4a, 4b is connected to a leakage drain, the duct also serves to connect the other indoor section 4b to the leakage drain.

The at least one passage channel 45 has because of its mouth to the associated head or base 43d, 44d, 43e, 44e a groove which can be produced in one step with the tooth profile, z. B. by a broaching, impact or rolling hammer tool. In order to increase the cross-sectional area of passageway 45, it is advantageous to provide passageways 45 in both opposing tooth head surfaces 43d and / or 44d and tooth space bases 43e and / or 44e radially to one another to arrange opposite. If a plurality of feedthrough channels 45 are arranged distributed opposite each other or alone on the circumference, the effective flow cross-section can be further increased.

The cross-sectional shape of the at least one feedthrough channel 45 may be rounded (FIGS. 2 and 5) or circular arc sectionally curved (FIG. 7) or angular (FIGS. 3 and 6), e.g. B. be square or triangular. In this case, the feedthrough channels 45 in the tooth head surfaces 43d, 44d and / or in the tooth space base surfaces 43e, 44e of the drive shaft 7 and / or the cylinder drum 17 can follow each other directly in the circumferential direction or omit one or more Zannkopfflächen 43d, 44d and / or tooth space base surfaces 43e, 44e be arranged. The above-mentioned and yet to be described embodiments may optionally be used in combination or in each case by itself.

In the embodiments of FIGS. 4 to 7, in which the same or comparable parts are provided with the same reference numerals, the spring 42 is disposed on the control disk 13 facing side of the multi-tooth clutch 19 in an arranged between the cylinder drum 17 and the drive shaft 7 annulus and preferably formed by a spiral spring which presses with its the control disk 13 facing the end against an inner shoulder surface 47 on the cylinder drum 17 and biases it against the control disk 13. The control disk 13 facing away from the end of the spring 42 spans with a plurality of oppositely arranged axial pressure pins 48 which extend through a respective feedthrough channel 45 to the support ring 39, the retraction device 33 before. Between the pressure pins 48 and the spring 42, a pressure ring 49 may be arranged. The length of the pressure pins 48 is dimensioned larger than the axial length of the multi-tooth clutch 19, so that they protrude into the annular space 46. There are several, distributed on the circumference arranged pressure pins 48 and these receiving Feedthrough channels 45 present to distribute the axial pressure force on the circumference.

In these embodiments, the passageways 45 form axial guides for the pressure pins 48. When the cross-sectional shape and size of the feedthrough channels 45 are adapted to the cross-sectional shape and size of the pressure pins 48 with a slight play of play, the feedthrough channels 45 only fulfill a guiding function for the pressure pins 48 In such a case, it can be ensured by another flow passage that the fluid passes from one housing interior section 4a to the other 4b, here into the annular space 46 and to the rolling bearing 11, in order to lubricate this area and, if necessary, also to cool it and / or to rinse. An adapted cross-sectional shape results z. B. then, if two z. B. semicircular feedthrough channels 45 are arranged opposite to each other, in which a common round or square pressure pin 48 engages with little play, as shown in FIG. 7 shows right.

It is advantageous to design the feedthrough channels 45 so that they both form a guiding function for the pressure pins 48 and also form at least one passage for the fluid. This can be achieved in that the number of feedthrough channels 45 is greater than the number of pressure pins 48 and thus at least one feedthrough channel 45 can serve as a free passage. But this can also be achieved in that the cross-sectional shape of the feedthrough channels 45 and 48 of the pressure pins is different. For this purpose, an angular shape for the feedthrough channels 45 and a round shape for the pressure pins 48 offers. Also in this case, opposing, z. B. in cross-section angular feedthrough channels 45 a common pressure pin 48 different z. B. round cross-sectional shape, record, as shown in Fig. 7 left. In this case, the feedthrough channels 45 a leadership function on the Pressure pins 48 exert by the latter are guided in a line and free passage channel cross-sections 45a remain, through which a fluid flow can take place.

All embodiments of the invention have in common that a weakening of the tooth flanks 43c and 44c is avoided. Since no teeth 43a, 44a omitted, despite the feedthrough channels 45 an effective connection between the drive shaft 7 and cylinder drum 17 is provided.

Claims (12)

1. Axial piston engine (1) having a housing (2), the housing interior (4) of which contains a cylinder drum (17) and a swash plate (26) disposed axially adjacent to the latter,
   wherein disposed in the cylinder drum (17) and extending substantially parallel to the centre line of the latter is a plurality of piston bores (21), in which pistons (23) are displaceably guided, of which the piston ends facing the swash plate (26) are supported against the swash plate (26),
   wherein a driving shaft (7) is rotatably mounted in the housing (2) and is connected non-rotatably to a engine part by a regular alternating arrangement of mutually meshing teeth (43a, 44a) and tooth spaces (43b, 44b) in peripheral direction, and
   wherein disposed in the region of the multitooth coupling (19) is at least one through-channel (45), which extends substantially parallel to the axis of rotation of the driving shaft (7) and from the one side of the multitooth coupling (19) to the other,
   characterized in
   that the through-channel (45) is disposed in a tooth tip surface (43b, 44e) and/or in a tooth space bottom surface (44e, 43b) lying opposite the latter, and
   that the through-channel (45) has a groove and discharges in the direction of the associated tooth tip surface (43b, 44e) and/or tooth space bottom surface (44e, 43b).
2. Axial piston engine according to claim 1,
   characterized in
   that the cross-sectional shape of the through-channel (45) is rounded or U-shaped.
3. Axial piston engine according to claim 1,
   characterized in
   that the cross-sectional shape of the through-channel (45) is polygonal, e.g. triangular or square.
4. Axial piston engine according to one of the preceding claims,
   characterized in
   that the through-channel (45) extends in both mutually opposing tooth tip surfaces (43d) and tooth space bottom surfaces (44d).
5. Axial piston engine according to one of the preceding claims,
   characterized in
   that a plurality of through-channels (45) distributed over the periphery are disposed in each case in a tooth tip surface (43d, 44d) and/or tooth space bottom surface (43e, 44e).
6. Axial piston engine according to claim 5,
   characterized in
   that a thrust pin (48) is disposed as part of a mechanical penetration and/or connecting apparatus in each of a plurality of through-channels (45) arranged so as to be distributed over the periphery and is preferably longer than the multitooth coupling (19).
7. Axial piston engine according to claim 6,
   characterized in
   that the thrust pins (28) are biased by the action of a spring (42) towards a return apparatus (39) for sliding pads (29).
8. Axial piston engine according to claim 6 or 7,
   characterized in
   that the shape and size of the cross section of the through-channels (45) are adapted to the shape and size of the cross section of the thrust pins (48).
9. Axial piston engine according to one of claims 6 to 8,
   characterized in
   that the through-channels (45) and the thrust pins (48) disposed therein have different cross-sectional shapes.
10. Axial piston engine according to one of claims 6 to 9,
    characterized in
    that the thrust pins (48) have a round cross-sectional shape.
11. Axial piston engine according to one of claims 6 to 10,
    characterized in
    that a thrust ring (49) is disposed between the ends of the thrust pins (48) remote from the return apparatus (33) and a pressure spring (42) formed in particular by a cylindrical helical spring.
12. Axial piston engine according to claim 11,
    characterized in
    that the thrust ring (49) and the thrust pins (48) are of an integral construction.

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