DE102013205263A1 - Hydrostatic axial piston machine in swashplate design - Google Patents

Abstract

The invention relates to a hydrostatic swash plate type axial piston machine, with a housing, the housing interior of which is closed to the outside by a connecting plate. With a cylinder drum, in which a plurality of axially continuous cylinder bores are evenly distributed on a pitch circle, in which pistons are arranged displaceably and which is rotatably supported in a first bearing via a through-opening formed on a wall of the housing or on the connecting plate. With a swash plate inclined at an angle to the longitudinal axis of the cylinder drum and drive shaft, on the sliding surface of which the pistons protruding from one side of the cylinder drum from the cylinder bores are supported with their one ends and at the other ends displacement spaces are formed in the cylinder bores. With hollow pistons which are axially displaceable in the ends of the cylinder bores facing away from the swash plate and which are sealed with respect to the cylinder drum and which, with their ends protruding from the cylinder bores, bear against a drum plate and are sealed against the drum plate which bears against the connecting plate with its side facing away from the cylinder drum. wherein the displacement spaces can be alternately connected via the hollow pistons and connecting channels formed in the drum plate to a low-pressure channel and high-pressure channel formed in the connecting plate. The drum plate is non-rotatably connected to the cylinder drum in the direction of rotation of the cylinder drum by means of the hollow pistons.

Description

The invention relates to a hydrostatic axial piston machine, which is designed according to the swashplate type and having the features of the preamble of claim 1.

This hydrostatic axial piston machine has a housing whose housing interior is closed by a connection plate to the outside, a cylinder drum in which a circle evenly distributed a plurality of axially continuous cylinder bores are formed, in which pistons are slidably mounted, and mounted in a housing drive shaft, with the the cylindrical drum is rotatably connected and which is guided via a formed on a wall of the housing or on the connection plate through-opening to the outside. A swash plate is inclined relative to the longitudinal axis of the cylinder drum and drive shaft by an angle. On the swash plate with its one ends on one side of the cylinder drum protruding from the cylinder bores piston are supported at the other ends in the cylinder bores Verdrängerräume are formed. At the ends facing away from the swash plate, hollow pistons sealed into the cylinder bores opposite the cylinder drum are used, which are sealed with their ends projecting from the cylinder bores against a drum plate in contact with and against the drum plate. The drum plate lies with its side facing away from the cylinder drum directly or indirectly to the connection plate, wherein the displacement chambers via the hollow piston and formed in the drum plate connecting channels are alternately connectable with a formed in the connection plate low-pressure channel and high-pressure channel. In indirect investment of the drum plate to the connection plate, would still be a distributor plate with kidney-shaped openings for the pressurized fluid between the drum plate and the connection plate.

In such axial piston machines, there is the problem of leakage and thus efficiency losses in the connection from the displacement chambers to the low-pressure channel and into the interior of the housing. It is from the German Patent 1 006 262 known to press the hollow piston by arranged in concentric recesses of the piston compression springs against the axially movable drum plate and this at the provided with kidney-like control openings control mirror of the connection plate. In this case, in one embodiment, the drum plate by a common for them and the cylinder barrel key with the drive shaft and thus rotatably connected to the cylinder drum. In another embodiment, the drum plate is connected via one or more axially extending dowel pins against rotation with the cylinder drum, which in turn is coupled via a feather key with the drive shaft.

This training is complex, has many components and requires a high assembly cost.

The object of the invention is therefore to provide an axial piston machine of the type mentioned, which avoids these disadvantages and has a simple and inexpensive construction.

This object is achieved in that the drum plate by means of the hollow piston in the direction of rotation of the cylinder drum is rotatably connected to the cylinder drum.

By this design, no separate components for rotational drive of the drum plate through the cylinder drum are required. The hollow piston meet in multiple function except the at least low leakage and thus low-efficiency loss connection from the displacement to the low-pressure channel and high-pressure channel and the rotational drive of the drum plate.

The hollow piston can be firmly connected to the drum plate or with the cylinder drum, which reduces the component and assembly costs.

But it is also possible that the hollow piston relative to the drum plate are axially displaceable and thus increased flexibility of the components between the cylinder barrel and the connection plate is achieved, which also leads to the reduction of leakage and thus efficiency losses.

Are cylinder drum and drive shaft fixedly connected to each other in the axial direction, in particular formed in one piece, so is bridged by the hollow piston depending on the different axial position of the cylinder drum due to tolerances and clearance different axial gap between the cylinder drum and the drum plate. It is a high flexural rigidity and thus a good concentricity of the unit of drive shaft and cylinder drum over the engine forces achieved, which also leads to the reduction of leakage and thus efficiency losses.

The hollow piston can protrude into driving bores of the drum plate with the same cross section as the cross section of the hollow pistons and can be axially displaceable therein for tolerance compensation, with the driving bores opening into the connecting ducts.

An axial tolerance compensation between the displacement chambers in the cylinder drum and connecting channels in the drum plate is achieved in a simple manner in that the hollow pistons have radially encircling annular grooves on their cylindrical outer lateral surfaces in the end regions projecting into the cylinder bores and / or in the end regions projecting into the driving bores , in which elastic ring seals are arranged, which are with their protruding from the annular grooves under bias on the cylindrical walls of the cylinder bores and / or the driving bores in abutment.

For permanent installation of the drum plate on the connection plate and thus to prevent leakage, the drum plate can be subjected to a force of force in contact with the connection plate.

In a simple training to evenly distributed to the cylinder drum or the drive shaft supported spring elements axially under bias to the drum plate in abutment.

Is in the rotatably mounted in the first bearing in a wall of the housing and outwardly guided drive shaft rotatably mounted at its other end in a second bearing which is arranged in a housing interior open to the housing and outwardly closed recess of the connection plate, so can the second bearing no hydraulic fluid to leak out, which also allows operation with low-viscosity hydraulic fluids.

The drive shaft which is rotatably mounted in the connecting plate in the first bearing can be guided outwards with its first end region and the cylinder drum can be rotatably mounted on the inner wall of the housing by means of a second bearing. This allows a large bearing distance despite only one implementation for the drive shaft to the outside.

If in this case the first bearing is arranged in a recess of the connection plate that is open to the interior of the housing and closed outwards, no hydraulic fluid can escape to the outside at the first bearing, which also enables operation with low-viscosity hydraulic fluids.

In a simple construction, the second bearing may be a sliding bearing arranged between the radially encircling lateral surface of the cylinder drum and the inner wall of the housing.

The swash plate may be an adjustable to different inclinations to the longitudinal axis of the drive shaft pivoting cradle.

In this case, the pivoting cradle is pivotally mounted on a wall of the housing via a slide bearing, in particular, the slide bearing consists of a partially circular cylindrical bearing surface of the pivoting cradle and a corresponding, this bearing surface receiving second bearing surface on or in the bottom of the housing, a large-area bearing is achieved.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below.

Show it

1 a cross section of a first embodiment of a hydrostatic axial piston machine and

2 a cross section of a second embodiment of a hydrostatic axial piston machine.

The swash plate type hydrostatic axial piston machines shown in the figures have a pot-like housing 1 on, at its pot opening from a connection plate 2 is closed.

Coaxial in the housing 1 is a rotatably mounted drive shaft 3 arranged in 1 through a welded joint 4 and in 2 by one-piece tightness with a cylinder drum 5 connected is.

In the cylinder drum 5 are evenly distributed on a pitch circle several axially continuous and thus easy to produce cylinder bores 6 formed in which pistons 7 slidably guided are arranged. At the one of the cylinder bores projecting ends of the pistons are joint balls 8th arranged in appropriate footprints of sliding shoes 9 intervene and over the sliding shoes 9 on sliding surfaces 10 a swash plate 12 ( 1 ) or swivel cradle 13 ( 2 ) are supported.

The sliding surfaces 10 are at an angle to the longitudinal axis 10 the drive shaft 3 inclined. In 1 This inclination is fixed while in 1 the pivoting cradle 13 is pivotally adjustable to different angles of inclination.

On the swash plate 12 or the pivoting cradle facing away from the piston 7 form the cylinder bores 6 displacer 14 , In these displacement rooms 14 stand out with their one Ends through holes 16 having hollow piston 15 into it, with their other ends in trained as blind holes driving holes 17 a drum plate 18 protrude. On the cylindrical outer surfaces of the in the displacement chambers 14 and the driving holes 17 protruding end portions of the hollow piston 15 are radially encircling annular grooves 19 formed in which ring seals 20 are arranged. With their out of the ring grooves 19 outstanding areas are the ring seals 20 with bias on the cylindrical walls of the displacement chambers 14 and the driving holes 17 on, so that the hollow piston 15 in the measure of the elasticity of the ring seals 20 to move axially and opposite the longitudinal axes of cylinder bores 6 and driving holes 17 can swing.

The driving bores 17 open at their bottom in the drum plate 18 trained and to the connection plate 2 open connection channels 21 ,

By evenly distributed on the cylinder drum 5 supported spring elements 22 becomes the drum plate 18 under tension in tight contact with the connection plate 2 pressed. On the same pitch circle as the connection channels 21 open in the connection plate 2 trained and outwardly leading a low pressure channel 23 and a high pressure channel 24 in the housing interior 28 , Through the hollow piston 15 becomes the drum plate made of a low friction material 18 upon rotation of the cylinder drum 5 with the cylinder drum 5 with turned. As a result, the low-pressure channel come 23 and the high pressure channel 24 alternating with the connecting channels 21 in surplus.

In the embodiment of the 1 That's one end of the shoot 3 through a passage opening 25 in the bottom of the case 1 led to the outside and one in the passage opening 25 arranged as a rolling bearing trained first camp 27 rotatably mounted.

The other end of the shoot 3 protrudes into one in the connection plate 2 trained, to the housing interior 28 open and closed recess 29 and is formed by an inserted into the recess as a rolling bearing second bearing 30 rotatably mounted.

In the embodiment of the 2 protrudes one end of the drive shaft 3 through a recess 29 ' in the connection plate 2 and a coaxial through-opening 31 outward.

In the recess, a rolling bearing is used, the first bearing 27 ' forms in this the drive shaft 3 rotatably mounted and secured to the inner ring against axial movement.

At the terminal plate facing away from the end portion of the cylinder drum 5 this is about a second camp 30 ' forming sliding bearing on the cylindrical inner wall 33 of the housing 1 rotatably mounted.

The pivoting cradle 13 is at her bottom 26 of the housing 1 facing side via a sliding bearing on the ground 26 pivoted. The sliding bearing consists of a teilkreiszylindrisch protruding bearing surface 32 the pivoting cradle 13 and a corresponding part-circular cylindrical, this bearing surface 32 receiving second storage area 34 in the ground 26 of the housing 1 ,

Because the storage area 32 approximately from the one edge region of the pivoting cradle 13 almost to the opposite edge region of the pivoting cradle 13 extends, the sliding bearing is advantageously formed over a large area.

By an adjusting device, not shown, the pivoting cradle 13 pivoted in the slide bearing and another angle of inclination of its sliding surface 10 to the longitudinal axis 11 the drive shaft 3 be set.

In the operation of the axial piston machines of the two figures as axial piston pump is the drive shaft 3 rotatably driven by an external rotary drive and sucks on the low-pressure channel 23 low-pressure hydraulic fluid in the displacement chambers 14 and promotes them at high pressure on the high-pressure channel 24 back out.

In the operation of the axial piston machines of both figures as axial piston motor hydraulic fluid under high pressure is the Verdrängerräumen via the high pressure passage 14 fed and sets the cylinder drum 5 and with it the outward propulsion shaft 3 in rotation. About the low pressure channel 23 then the discharged under low pressure hydraulic fluid is discharged again.

Between the drum plate 18 and the connection plate 2 can still be arranged a distributor plate with kidney-shaped openings for the pressurized fluid.

A hydraulic swash plate machine according to the invention can be used with particular advantage as a component of a hydraulic hybrid drive in a motor vehicle, in particular in a passenger vehicle. In vehicles, it comes in a special way to a high efficiency with a simple design.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1006262 [0003]

Claims (13)

Hydrostatic axial piston machine in swashplate design, with a housing ( 1 ), whose housing interior ( 28 ) from a connection plate ( 2 ) is closed to the outside, with a cylinder drum ( 5 ), in which evenly distributed on a pitch circle several axially continuous cylinder bores ( 6 ) are formed, in which piston ( 7 ) are arranged displaceably, and the one on a wall of the housing ( 1 ) or on the connection plate ( 2 ) formed through opening ( 25 . 31 ) outward drive shaft ( 3 ) in a first warehouse ( 27 . 27 ' ) is rotatably mounted, with a longitudinal axis ( 11 ) of cylindrical drum ( 5 ) and drive shaft ( 3 ) inclined at an angle swash plate ( 12 ), on which the one side of the cylinder drum ( 5 ) from the cylinder bores ( 6 ) with their one end protruding piston ( 7 ) are supported at the other ends in the cylinder bores ( 6 ) Displacement rooms ( 14 ) are formed, with hollow piston ( 15 ), which are adjacent to the swashplate ( 12 ) facing away from the outer side of the cylinder drum ( 5 ) sealed in the cylinder bores ( 6 ) are used and with their from the cylinder bores ( 6 ) protruding ends on a drum plate ( 18 ) in plant and opposite the drum plate ( 18 ), which are secured against rotation with the cylinder drum ( 5 ) and with its the cylinder drum ( 5 ) facing away from the terminal plate directly or indirectly ( 2 ), wherein the displacement chambers ( 14 ) over the hollow piston ( 15 ) and in the drum plate ( 18 ) formed connection channels ( 21 ) alternating with one in the connection plate ( 2 ) formed low pressure channel ( 23 ) and high pressure channel ( 24 ) are connectable, characterized in that the drum plate ( 18 ) by means of the hollow piston ( 15 ) in the direction of rotation of the cylinder drum ( 5 ) rotatably with the cylinder drum ( 5 ) connected is. Hydrostatic axial piston machine according to claim 1, characterized in that the hollow piston are fixedly connected to the drum plate. Hydrostatic axial piston machine according to claim 1, characterized in that the hollow pistons ( 15 ) opposite the drum plate ( 18 ) are axially displaceable. Hydrostatic axial piston machine according to one of the preceding claims, characterized in that cylinder drum ( 5 ) and drive shaft ( 3 ) are firmly connected. Hydrostatic axial piston machine according to claim 4, characterized in that cylinder drum ( 5 ) and drive shaft ( 3 ) are integrally formed. Hydrostatic axial piston machine according to one of claims 3 to 5, characterized in that the hollow piston ( 15 ) in driving bores ( 17 ) of the drum plate ( 18 ) with the same cross section as the cross section of the hollow piston ( 15 ) and are preferably axially displaceable therein, wherein the driving bores ( 17 ) in the connection channels ( 21 ). Hydrostatic axial piston machine according to claim 6, characterized in that the hollow pistons ( 15 ) on their cylindrical outer lateral surfaces in the in the cylinder bores ( 6 ) projecting end portions and / or in the driving bores ( 17 ) projecting end portions radially encircling annular grooves ( 19 ), in which elastic ring seals ( 20 ) are arranged, with their from the annular grooves ( 19 ) outstanding areas under bias on the cylindrical walls of the cylinder bores ( 6 ) and / or the driving bores ( 17 ) are in plant. Hydrostatic axial piston machine according to one of the preceding claims, characterized in that the drum plate ( 18 ) of at least one spring element ( 22 ) in the sense of an attachment to the connection plate ( 2 ) is subjected to force. Hydrostatic axial piston machine according to claim 8, characterized in that evenly distributed on the cylinder drum ( 5 ) or the drive shaft ( 3 ) supported spring elements ( 22 ) axially biased on the drum plate ( 18 ) are in plant. Hydrostatic axial piston machine according to one of the preceding claims, characterized in that that in which in the first bearing ( 27 ) in a wall of the housing ( 1 ) rotatably mounted and outwardly guided drive shaft ( 3 ) at its other end portion in a second bearing ( 30 ) is rotatably mounted, which in a housing interior ( 28 ) open and preferably outwardly closed recess ( 29 ) of the connection plate ( 2 ) is arranged. Hydrostatic axial piston machine according to one of claims 1 to 9, characterized in that in a first bearing ( 27 ' ) rotatably mounted drive shaft ( 3 ) is guided with its first end portion to the outside and the cylinder drum ( 5 ) by means of a second bearing ( 30 ' ) on the inner wall ( 33 ) of the housing ( 1 ) is rotatably mounted. Hydrostatic axial piston machine according to claim 11, characterized in that the first bearing ( 27 ' ) in the connection plate ( 2 ) is arranged. Hydrostatic axial piston machine according to one of claims 11 and 12, characterized characterized in that the second bearing ( 30 ' ) between the radially circumferential circumferential surface of the cylinder drum ( 5 ) and the inner wall ( 33 ) of the housing ( 1 ) is arranged sliding bearing.

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