JPH04276101A - Axial piston machine - Google Patents

Abstract

PURPOSE: To manufacture a holder inexpensively, and easily assemble it by preventing the motion in the axial direction of a holding plate by the holder to be locked in a bayonet coupling shape in the axial direction. CONSTITUTION: A working piston 8 of a swash plate type axial piston machine is supported by a swash plate 11 through a slide shoe 9, and a holding plate 12 ensures the slide shoe 9 from an inconvenient separating motion from the swash 11 during, for example, the sucking motion.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a swash plate type axial piston machine, in which a working piston disposed in a cylinder drum so as to be movable in the longitudinal direction is supported by the swash plate via a sliding shoe. The sliding shoe is held against undesirable separation from the swash plate by a retaining plate rotating synchronously with the cylinder drum, the axial movement of the retaining plate being prevented by the retaining device.

0002

BACKGROUND OF THE INVENTION An axial piston machine of the above type is known from DE 32 22 210 A1. In this case, the holding plate is supported by a holding device in the form of a spherical cap-like component that can be loaded with spring force, and the sliding shoe is tilted by the action of the mass inertia force and the suction force on the piston when the cylinder drum rotates. It is designed not to be separated from the board. In such an arrangement, the spring force exclusively limits the tilting rotational speed of the axial piston machine, so that the spring force must be designed in accordance with the maximum forces occurring during operation of the machine. A disadvantage is therefore that during normal operation, especially at the beginning of starting the machine, high friction occurs between the sliding shoe and the swash plate. In order to eliminate this drawback, it has been proposed to bring the retaining plate or a spring-loaded component into contact with the stop of the drive shaft, so that the force of the spring is not applied to the sliding shoe at least in the stopped state of the machine, but to the stop. It is intended to be transmitted to Only when the sliding shoes have moved apart beyond a predetermined distance does an action on the sliding shoes via the component and the retaining plate prevent a further movement of the sliding shoes away. To ensure satisfactory functioning of axial piston machines, manufacturing and installation tolerances must be kept extremely small.

In the literature of the Federal Republic of Germany, Krauss
kopf-Taschenbuecher “Oelh
ydraulik undPneumatik”Ba
Elemente der Oelhydrauli
k, TB3, Teil I, “Geraete
Another type of holding device is shown in Figure 3 on page 89 under ``Devices for Energy Conversion''. In the axial piston machine shown here, the holding plate screws into the swashplate. This is ensured against axial displacement by means of plate-like components which are fixed in place.In this case too, manufacturing tolerances must be kept small.Furthermore, the assembly costs are high.

0004

SUMMARY OF THE INVENTION It is an object of the invention to improve an axial piston machine of the type mentioned at the outset, so that the manufacturing and assembly costs of the axial piston machine are low.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides that the holding device is locked in the axial direction by means of a bayonet connection. The idea of the invention is to configure the holding device in the form of a bayonet connection by means of a special shape of the holding device and its corresponding surface.

[0006]

The embodiment of the invention requires only a small number of components, and the manufacturing and assembly costs of the axial piston machine are kept low.

[0007] In an advantageous embodiment of the invention, the retaining device has a circular retaining ring, the inner diameter of the retaining ring being smaller than the outer diameter of the retaining plate, and the retaining ring extending radially around the outer circumference. a protrusion on the swash plate side or on the machine casing side, the protrusion being located further away from the protrusion in the axial direction from the swash plate and extending in the direction of the central axis of the retaining ring; The alignment is achieved by rotating the retaining ring by a predetermined angular amount about the central axis of the retaining ring. A holding device of such construction is easy to manufacture and allows rapid assembly. The retaining ring absorbs the piston acceleration forces occurring at high speeds or during suction operation and limits the separation movement of the sliding shoe to a minimum axial play. Such axial play is determined by a suitable combination of the individual components, namely the sliding shoe, the retaining plate, the retaining ring and, if appropriate, the running plate arranged between the swashplate surface and the sliding shoe. It is also possible to form one of these components with different thicknesses and to define the axial play by selecting and installing a component of the appropriate thickness.

[0008] The retention of the sliding shoe takes place by form-fitting. The projection on the side of the retaining ring and the projection which cooperate with each other in a bayonet manner are preferably provided on the inner wall of the machine housing in constant-displacement axial piston machines. In axial piston machines with variable displacement, the projections are preferably provided on the swashplate, for example on a ring-shaped wall around the periphery of the swashplate. It is also possible to provide the projection in the inner region of the swashplate, ie in the immediate vicinity of the drive shaft. In an advantageous embodiment of the invention, the protrusion on the side of the swash plate or on the machine housing is arranged on the circumferential section of the swash plate that redirects the movement of the working piston. As a result, the holding force is received in the range of the dead center where the maximum acceleration force of the working piston occurs. The holding plate is therefore only slightly deformed.

In axial piston machines with a constant swash plate angle, it is advantageous if the maximum outer diameter of the retaining ring is smaller than the width of the casing in the area of the recess between the projections on the machine casing side; The circumferential dimension of the protrusion on the ring side is smaller than the distance between two adjacent protrusions on the machine casing side. This makes installation of the holding device extremely easy. During installation, the retaining ring is rotated so that the projections of the retaining ring are located in the recesses between the projections of the machine casing. Then,
The retaining ring is inserted into the machine casing and rotated through a predetermined angle about the central axis, so that the projections of the retaining ring and the machine casing overlap each other and lock the retaining ring.

In order to introduce the holding force evenly into the machine housing, the retaining ring and the machine housing are preferably each provided with four projections, the projections having a cross section perpendicular to the central axis of the retaining ring. They are arranged at uniform intervals in the circumferential direction.

The inner diameter of the retaining ring is slightly larger than the outer diameter of the cylinder drum. The obliquely arranged retaining ring must maintain a certain axial distance with respect to the cylinder drum. Therefore, in an advantageous embodiment of the invention, the central axis of the retaining ring is offset eccentrically with respect to the central axis of the cylinder drum. This allows sufficient access to the cylinder drum. Therefore, there is no need for the working piston to be pulled out as far from the cylinder bore as would be the case if the working piston were centered around the retaining ring. This keeps the stress on the edges of the guide bushing in the cylinder bore low. The length of the machine can also be kept small.

[0012] In order to secure the installed position of the holding device, the holding device is fixed at the locking position by a rotation prevention mechanism. In an advantageous embodiment of the invention, the anti-rotation mechanism is formed by a pin which can be mounted from the outside of the machine casing, the pin extending parallel to the central axis of the retaining ring and between two overlapping projections of the retaining ring and the machine casing. It passes through the section. This makes it extremely easy to incorporate the anti-rotation mechanism.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A swash plate type constant discharge axial piston machine has a machine casing, and the machine casing supports a drive shaft 4 via bearings 2 and 3. A drive shaft 4 is non-rotatably connected to a cylinder drum 5, which cylinder drum has a number of cylinder holes 6. A guide bush 7 is mounted in the cylinder bore 6, in which a working piston 8 is movable. The working piston 8 is supported via a hydraulically relieved sliding shoe 9 with a running plate 10 interposed on a swash plate 11, which in the exemplary embodiment is correspondingly designed in the machine housing. It is made up of slanted surfaces. The movement of the sliding shoe 9 away from the running plate 10 of the swash plate 11 is prevented by a circular ring-shaped holding plate 12, which has a cutout 1 for receiving the sliding shoe neck.
It has 3. A retaining ring 14, also in the form of a circular ring, is brought into contact with the retaining plate 12, and this retaining ring 14 is provided on its outer periphery with four radial protrusions 15 arranged at uniform intervals. The shape of the retaining ring 14 is shown in FIG. The inner diameter of the retaining ring 14 is smaller than the outer diameter of the retaining plate 12. The interior of the machine casing 1 is also provided with protrusions 16 arranged at uniform intervals from one another. A protrusion 16 provided inside the machine casing and extending towards the central axis 19 of the retaining ring is located at a distance from the swash plate to the protrusion 15 provided on the retaining ring by the thickness of the protrusion 15. There is. The projection 15 of the retaining ring 14 and the projection 16 of the machine casing 1 act as a bayonet connection. The cutouts 17 provided between the projections 16 of the machine casing 1 are sufficiently large to receive the projections 15 of the retaining ring 14 . In the position shown in Figure 2, retaining ring 1
4 is inserted into the machine casing 1. Next, the retaining ring 14 is rotated by a predetermined angle (approximately 45° counterclockwise in the embodiment) about the central axis 19, thereby causing the retaining ring 14 as well as the retaining plate 1 to rotate.
2, and thus the sliding shoe 9 is held with a certain axial play so that it does not move away from the running plate 10. This position is shown in FIG. 3 as well as in FIG.
The pin is inserted from the outside of the machine casing 1 and is fixed by one protrusion 1 on the machine casing side.
6, and a protrusion 15 that matches the protrusion. As is clear from the relationship between FIGS. 1 and 2, the center axis 19 of the retaining ring 14 is aligned with the center axis 20 of the cylinder drum 5.
is eccentrically shifted by a predetermined amount “e” with respect to
This allows the cylinder drum 5 to enter the inner bore of the retaining ring 14 (left side in FIG. 1).

[Brief explanation of the drawing]

FIG. 1 shows a longitudinal section through an axial piston machine according to the invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

3 is a sectional view taken along line II-II in FIG. 1 with the holding device locked; FIG.

[Explanation of symbols]

Claims (8)

[Claims] 1. An axial piston machine of the swash plate type, in which a working piston arranged longitudinally movably in a cylinder drum is supported on the swash plate via a sliding shoe, and the sliding shoe is connected to the cylinder drum. of the type which is held against undesirable separation from the swash plate by a synchronously rotating retaining plate and in which axial movement of the retaining plate is prevented by the retaining device, the retaining device being axially An axial piston machine characterized in that it is locked by a bayonet connection. 2. The retaining device has a circular retaining ring (14), the inner diameter of the retaining ring is smaller than the outer diameter of the retaining plate (12), and the retaining ring has a radial direction on the outer periphery. The projection (15) extends from the swash plate in the axial direction.
A protrusion (16) on the swash plate side or machine casing side that is located further away from the center axis (19) of the retaining ring (14) and extends in the direction of the central axis (19) of the retaining ring (14); 2. Axial piston machine according to claim 1, wherein the retaining ring (14) is adapted to be aligned by rotating the retaining ring (14) by a predetermined angular amount. 3. Axial piston machine according to claim 2, characterized in that the protrusion (16) on the side of the swash plate or on the machine housing side is arranged on a circumferential section of the swash plate that changes the direction of movement of the working piston (8). 4. The maximum outer diameter of the retaining ring (14) is smaller than the casing width within the range of the notch (17) between the protrusions (16) on the machine casing side, and Axial piston machine according to claim 2 or 3, characterized in that the circumferential dimension of the section (15) is smaller than the distance between two adjacent projections (16) on the machine casing side. 5. The retaining ring (14) and the machine casing (1) are each provided with four protrusions (15, 16), and the protrusions are aligned with the central axis (19) of the retaining ring (14).
5. The axial piston machine according to claim 4, wherein the axial piston machines are uniformly spaced apart from one another in the circumferential direction when viewed in a section perpendicular to ). [Claim 6] The central axis (19) of the retaining ring (14)
6. Axial piston machine according to claim 2, wherein the cylinder drum (5) is eccentrically offset with respect to the central axis (20) of the cylinder drum (5). 7. The axial piston machine according to claim 1, wherein the holding device is fixed in the locking position by a rotation prevention mechanism. 8. The anti-rotation mechanism is formed by a pin (18) that can be attached from the outside of the machine casing,
8. The pin according to claim 7, wherein the pin passes through two overlapping projections (15, 16) of the retaining ring (14) and of the machine casing (1) parallel to the central axis (19) of the retaining ring (14). Axial piston machine.