JPS631465B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a rotating cylinder drum, and the cylinder drum is provided with a plurality of cylinders arranged at least approximately parallel to the axis of the cylinder drum. The present invention relates to an axial piston machine in which each piston has an axle which is movable and whose axis forms a fixed or variable angle with the axis of rotation of the cylinder drum. The shaft is fixedly connected to the drive flange, and the piston rod is supported by the drive flange so that a circumferential force is transmitted from the piston to the drive flange. This circumferential force, in conjunction with the bearing force on the shaft, generates a torque on the drive flange. The cylinder drum rotates together with the drive flange and is entrained via the circumferential force transmitted from the drive flange to the cylinder drum via the piston rod. In conventionally known machines, this circumferential force is transmitted either by each piston rod contacting the inner circumferential surface of a piston skirt, from which the force is transmitted to the cylinder wall, or by the piston rods directly This takes place by contacting a part configured as a disc arranged in front of the cylinder drum, which is fixedly connected to the inner wall of the cylinder bore or to the cylinder drum. Furthermore, it is already known that the piston rod itself is provided with a spherical large diameter part, this spherical large diameter part acts directly as a piston, and the piston rod part connected to this large diameter part is brought into contact with the inner circumferential wall of the cylinder. It is. In all these machines, the force required to entrain the cylinder drum is transmitted by only one piston rod in any operating state, but each piston rod sequentially moves only once during one rotation of the drive flange. Contact to transmit force. That is, each piston rod contacts its associated driving surface only once during one rotation and transmits force to this driving surface, so that during one rotation of the cylinder drum, contact processes corresponding to the number of cylinders occur. arise. This contact process acts as a hard impact at high rotational speeds. To avoid this and to distribute the force evenly, in axial piston machines where the force is transmitted to the piston skirt by the piston rod, an elastic lining is provided on the inner surface of the piston skirt or on the outer surface of the piston rod. It is known to fill the space between the piston skirt and the piston rod with an elastic material (DE 1232025). By such an arrangement, a somewhat even distribution of the force on two or more piston rods is achieved, although in each case a hard shock of the piston rod initiating the force transmission is avoided. Such a configuration is not widely used in practice today. This is because in this case the loads that the elastic material has to absorb and thus the number of elastic deformations are extremely large.

In order to entrain the cylinder drum with a rotating drive flange, it is known to provide automatic couplings in the space in which the piston rod rotates or to provide teeth on the outside of the cylinder drum and the drive flange, respectively. Teeth on the outside of the cylinder drum work well if the angle between the cylinder drum axis and the drive flange axis is fixed, but it is expensive, requires a lot of space, and adds weight. or,
Universal joints located within said space are not very effective.

The object of the invention is to improve the entrainment of a cylinder drum by a system of piston and piston rod and to avoid the disadvantages of previously known devices.

According to the present invention, in the axial piston machine of the type mentioned at the beginning, the part with which each piston rod comes into contact is the cylinder drum part itself, which is arranged closer to the drive flange than the cylinder of the cylinder drum, Contact holes are provided in this cylinder drum section, which are assigned to each cylinder and which have a larger diameter than the cylinder or whose axis does not coincide with the cylinder axis, and these contact holes are arranged to accommodate the entraining force. This problem was solved by being structured so that it can transmit the following information. With this configuration, each cylinder is assigned a contact hole located on the drive flange side of the cylinder drum, and this contact hole can receive the circumferential force from the piston rod, thereby reducing the During operation of the shear piston machine, the piston rod does not come into contact with the inner wall of the cylinder and transmit a force in the circumferential direction, so that the piston rod does not wear out the inner wall of the cylinder. The axis of the contact hole does not need to be coaxial with the cylinder axis. For example, the two axes can be offset parallel to each other or the two axes can be arranged at an angle with or without intersecting. Further, the contact hole does not need to have a circular cross section, but may have an elliptical cross section or a regular triangular cross section with rounded corners, for example. Further, the contact hole is not cylindrical, but may widen conically toward the drive flange. In addition, since the piston rod always comes into contact with a predetermined inner circumferential area of the contact hole, only this inner circumferential area must be precisely processed and formed appropriately, or have special wear resistance or sliding characteristics. It may be coated with a layer.
This contact hole can be suitably designed in the circumferential direction or curved in the direction of the cylinder axis, for example in the shape of a trumpet, in order to adapt to different angles of deflection of the piston rod. In this case the piston rod can be cylindrical. It is also advantageous if the contact area of the piston rod is coated with an elastic material. If this elastic material does not have sufficient wear resistance, a further wear-resistant layer, for example a steel surface in the form of a steel bushing, can be provided. However, the elastic and/or wear-resistant layer may be arranged only on the peripheral wall part of the contact hole in contact with the piston rod, or the steel bushing may have a particularly thick wall thickness in the area of contact with the piston rod. It is also possible to design the steel bushings asymmetrically.
Similarly, the elastic material can also have a large wall thickness in the region subjected to compressive loads.

With the configuration of the present invention, it becomes possible to rotate the cylinder drum axis over a large angle with respect to the drive shaft axis and obtain a large piston stroke. There are two methods to prevent the axis of the piston rod from being excessively deviated from the axis of the cylinder even when the rotation angle is large. One method is to make the pitch diameter in which the piston rod universal joint is located on the drive flange larger than the pitch diameter in which the cylinder is located in the cylinder drum. This itself is already known. If the drive flange is tilted with respect to the cylinder drum axis, the piston rod will be deflected inwardly, so by configuring it as described above, the inward deflection is caused by the fact that both pitch diameters are the same size. become smaller than it was at some point. Another method is to place the center axis, when the cylinder drum shaft is pivoted relative to the drive shaft axis, outside the plane in which the piston rod is connected to the drive flange, but in front of this plane.

The piston rod is usually mounted on the drive flange with a ball joint. The drive flange is provided with a spherical bearing surface on which the spherical head of the piston rod is held by a retaining ring. The dimensions given to this retaining ring may limit the pivoting angle. In order to increase the limit range provided by this retaining ring, according to one embodiment of the invention, this retaining ring is not circular, but is chamfered on one side or on both sides facing each other for the foot of the piston rod. Therefore, only the side portions are involved in fully absorbing the pressing force, and the chamfered portion absorbs as much of the pressing force as possible due to the chamfer. The retaining ring can also be configured to correspond to two sides of a triangle.

What is important in the embodiment of the axial piston machine according to the invention is that each piston is connected to the drive flange by a piston rod, and that all piston rods take part in turn to entrain the cylinder drum and for this purpose the cylinder In axial piston machines, contact holes assigned to the individual cylinders are provided for the contact of the piston rod in one place on the drum. As already mentioned, this contact hole can be larger than the diameter of the cylinder.

The invention will now be explained with reference to the drawings: In the exemplary embodiment shown, the cylinder drum 1 is mounted rotatably about the cylinder drum axis in a manner not shown and rests on an end face 2 on a control plate, not shown. ing. The supply of working fluid to the cylinder 3 is controlled by this control plate. A piston 4 is slidable within the cylinder 3. Each piston 4 is connected to a piston rod 5 by a spherical head 6. Each piston rod 5 also has a spherical head 7 at its end opposite the spherical part 6, by means of which the piston rod 5 rests on a drive flange 8. The drive flange 8 is fixedly connected to the drive shaft 9.

On the side of the drive flange, the cylinder drum 1 is provided with a contact part 10 in front of the part of the cylinder drum containing the cylinder 3. This contact part 10 is provided with a contact hole 11 assigned to each cylinder 3 . Each contact hole 11 has a lining layer 12 of elastic material. This lining layer 12
Inside is a bushing 1 made of highly wear-resistant steel.
3 is inserted. The piston rod 5 is provided with a truncated conical contact part 14 which can come into contact with the inner peripheral surface of the bush 13. This contact part 14 is also provided with a protective sleeve 15 made of highly wear-resistant steel. This protective sleeve 15 is connected to the piston rod 5 by an intermediate layer 16 of elastic material.

When the drive flange 8 rotates around the axis of the drive shaft 9, the piston rod 5 causes the piston 4 to reciprocate within the cylinder 3 in the cylinder axis direction. In this case, one of the piston rods 5 contacts the inner circumferential surface of the bush 13 with a contact portion 14 and transmits a circumferential force. As a result, the cylinder drum 1 is entrained by the rotating drive flange 8. That is, since the contact portion 14 of the piston rod 5 does not come into contact with the inner peripheral surface of the cylinder hole 3 itself, the contact of the contact portion 14 does not cause wear on the inner peripheral surface of the cylinder hole. In this case, the highly wear-resistant layers, ie sleeve 15 and bush 13, are always in contact with each other. In a further embodiment of the invention, either the sleeve 15 or the bush 13 can be designed as a sliding metal layer.

Since the contact part 14 always contacts only a predetermined area of the bush 13, one embodiment of the invention provides an extra large wall thickness for the bush 13 and/or the intermediate layer 12 in the area where the contact part 14 contacts the bush 13. It is possible to give a sense of security. In particular, for this purpose it is possible to arrange the axis of the contact hole 11 offset with respect to the axis of the cylinder 3, in contrast to the illustrated embodiment.

In the illustrated embodiment, care must be taken that at high rotational speeds the space between the end face of the contact part 14 and the piston 4 does not behave like a stepped piston. In other words, piston 4 is in cylinder 3
Sufficient flow cross-section must be provided so that the working fluid is displaced from the aforementioned space when forced into it. This flow cross section may be the space between the outer peripheral surface of the contact part 14 and the inner peripheral surface of the bush 13, or an additional hole in the contact part 14, or an additional hole in the contact part 10. It may be hot. These holes are arranged at least approximately radially in the contact part 10 and in the contact part 14.
The space between the end face of the bush 13 and the piston 4 is connected to the outer periphery of the cylinder drum 1, or the space inside the bush 13 is connected to each other.

In the embodiment shown, the drive flange 8 has a spherical head 7.
The pitch circle diameter of the spherical bearing surface arranged for this purpose is selected to be larger than the pitch circle diameter at which the axis of the cylinder 3 of the cylinder drum 1 is arranged. This diameter ratio is such that the deflection angle for the piston rod 5 is suitable when the angle between the axis of rotation of the cylinder drum 1 and the axis of rotation of the drive shaft is at its maximum or a value that occurs more frequently during operation. or is chosen to be minimum or such that the deflection angle of the piston rod 5 is equal when the pivot angle between both axes of rotation is 0° and at the maximum. To be elected. By offsetting the axis of the contact hole 11 to a larger pitch diameter than the axis of the cylinder 3, it is also possible to reduce the necessary conicity of the contact part 14 of the piston rod 5.

Furthermore, in another embodiment of the present invention, the inner circumferential surface of the contact hole 11 or the bush 13 can be configured in a conical shape. In this case, the piston rod 5
can be cylindrical. However, both the contact part 14 of the piston rod 5 and the surface on the contact part 10 which cooperates with this contact part 14 can also be conical.

The intermediate layers 12, 16 are made of a suitable material, such as plastic or oil-resistant rubber, but may also be made of spiral leaf springs.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention,
1 is a cross-sectional view of an axial piston machine with a contact hole having a larger diameter than the cylinder; FIG. 1...Cylinder drum, 3...Cylinder, 4...
... Piston, 5 ... Piston rod, 6 ... Spherical head, 7 ... Spherical head, 8 ... Drive flange, 9 ...
... Drive shaft, 10 ... Contact part, 11 ... Contact hole,
12... Intermediate layer, 13... Button, 14... Contact portion, 15... Protective sleeve, 16... Intermediate layer.

Claims (1)

[Scope of Claims] 1. A rotating cylinder drum, which is provided with a plurality of cylinders arranged at least approximately parallel to the axis of the cylinder drum, and one piston in each cylinder. is slidable and has a shaft whose axis forms a fixed or variable angle with the axis of rotation of the cylinder drum, the shaft being fixedly connected to the drive flange, the drive flange The piston rod is supported by the drive flange so that a circumferential force is transmitted from the piston to the piston, and the cylinder drum rotates together with the drive flange and the circumferential force is transmitted by the piston rod to entrain the cylinder drum. In an axial piston machine configured to transmit power to a cylinder drum, the part with which each piston rod comes into contact is the cylinder drum part itself, which is located closer to the drive flange than the cylinder of the cylinder drum, and the cylinder drum The parts are provided with contact holes assigned to each cylinder that have a larger diameter than the cylinder or have an axis that does not coincide with the cylinder axis, and these contact holes can transmit the entrainment force. An axial piston machine characterized in that it is configured as follows. 2. Axial piston machine according to claim 1, wherein the diameter of the contact hole increases gradually in the axial direction, in particular continuously in a linear or curved manner towards the drive flange. 3. Axial piston machine according to claim 1, wherein the contact hole is provided with a lining made of an elastic material. 4. Axial piston machine according to claim 1, wherein the contact hole is provided with a wear-resistant lining (13). 5. Axial piston machine according to claim 4, in which the wear-resistant lining is supported on an elastic cushion. 6. Axial piston machine according to claim 5, characterized in that the elastic cushion (and) or the wear-resistant lining is arranged asymmetrically along the inner circumference of the contact hole. 7. Axial piston machine according to claim 1, characterized in that the piston rod is provided with a wear-resistant lining in the area in which it cooperates with the contact bore. 8. Claim 1, wherein the piston rod is provided with an elastic lining in the area where it cooperates with the contact hole.
Axial piston machine as described in section. 9. The piston is connected to the drive flange by a piston rod, and the center axis of rotation when the cylinder drum is rotated relative to the drive shaft is closer to the cylinder drum than the plane of connection between the piston rod and the drive flange. , an axial piston machine according to claim 1.