EP1272735B1 - Radial piston engine - Google Patents

Description

The invention relates to a radial piston machine according to the preamble of claim 1.

A radial piston machine is known from DE 40 049 32 C2 known in which a cylinder block with a variety of in the radial direction arranged cylinder spaces rotatable in is housed in a housing. There is one in each cylinder space Piston guided, its protruding from the cylinder block End portion is supported on a cam ring. This lifting ring has a variety of control cams that are used in the Rotation of the cylinder block is a radial displacement of the Piston takes place. Are in the housing of the radial piston machine Inlet and return channels designed for pressure medium, alternately with tax breaks in the cylinder block can be brought into overlap via which the pressure medium supply and discharge to and from the cylinder rooms controllable is.

In the embodiment disclosed in DE 40 049 32 C2 are the tax breakthroughs in the cylinder and the mouth cross-sections in the housing with a circular Cross section executed. A disadvantage of such Solution is that the connection to the cylinder rooms comparatively due to the circular control cross-sections is slowly opened or closed so that flow losses may occur.

This disadvantage is compounded by one in the EP 0 263 218 B1 overcome solution in which the control cross-sections are not circular but rather are trapezoidal. The side faces of this Trapezoidal cross sections can go inwards be arched or flat.

Such a solution does indeed allow flow losses when opening and closing the connection minimize the cylinder spaces, but one is required considerable manufacturing effort to the to form trapezoidal control breakthroughs.

In contrast, the invention is based on the object to create a radial piston machine with minimal Flow losses and minimal manufacturing effort is producible.

This task is accomplished by a radial piston machine solved with the features of claim 1.

According to the invention the end face sections of tax breakthroughs or muzzle cross sections in the cylinder block of the Radial piston machine formed by two holes. The breakthroughs in control the pressure medium supply and discharge are therefore with curved end faces executed, with the end faces in the radial direction inner or outer peripheral surface sections be understood. Such curved end faces are much easier than those from the EP 0 263 218 A1 known straight end face sections produce so that the manufacturing Effort is minimized. Such a tax cross section is due to the extension of the tax breakthrough in the radial direction adaptable without increasing it the width (transverse to the radial direction).

The radius of curvature of the radially inner end face section is preferably less than that of the radially outer end face section executed.

In the solution known from DE 40 049 32 C2 the enlargement of the control cross section only by enlargement of the diameter possible. Because the tax breaks and preferably the mouth cross sections are designed with zero coverage, is the maximum width of tax breakthroughs and mouth cross-sections limited so that the bore diameter in the known Solution is not expandable.

The manufacture of the breakthroughs is particularly simple, if the two holes overlap each other so that the Breakthroughs simply by making the two holes can be executed and then an approximately eight-shaped Have cross-section.

Alternatively, the curved end faces are connected to each other via tangential surfaces. at the intersection lies at different radii of curvature of the two tangential surfaces in the axis of symmetry of the radially inwardly tapering control cross section lies.

Manufacturing is particularly simple if the geometry the control breakthroughs on the cylinder block and of the mouth cross sections on the housing are chosen identically is. As mentioned above, it is preferred that the mouth cross-sections and the tax breakthroughs are executed with zero overlap with each other, so that the fastest possible opening and closing of the connection to the cylinder rooms is guaranteed.

The production of the tax breakthroughs and the mouth cross-sections can be further simplified if these are each formed in a control disk, which are attached to the cylinder block or the housing.

Other advantageous developments of the invention are the subject of further subclaims.

Figur 1 einen Querschnitt durch einen Radialkolbenmotor;

Figur 2 eine Detaildarstellung einer Steuerscheibe zur Steuerung der Druckmittelzufuhr und -abfuhr zu Zylinderräumen der Radialkolbenmaschine;

Figur 3 geometrische Details eines Steuerdurchbruchs der Steuerscheibe aus Figur 2;

Figur 4 eine vereinfachte Ausführung eines Steuerdurchbruchs für eine Steuerscheibe gemäß Figur 2 und die

Figuren 5 und 6 weitere vereinfachte Ausführungen eines Steuerdurchbruchs.

Preferred exemplary embodiments are explained in more detail below with the aid of schematic drawings. Show it:

Figure 1 shows a cross section through a radial piston motor;

FIG. 2 shows a detailed illustration of a control disk for controlling the pressure medium supply and discharge to cylinder spaces of the radial piston machine;

FIG. 3 geometrical details of a control breakthrough of the control disk from FIG. 2;

4 shows a simplified version of a control breakthrough for a control disk according to FIG. 2 and FIG

Figures 5 and 6 further simplified versions of a tax breakthrough.

Figure 1 shows a greatly simplified sectional view a radial piston engine 1, which works on the multi-stroke principle is constructed. This radial piston motor 1 has one Housing 2, on which a cam ring 4 is screwed. An output shaft 6 is mounted within the housing 2, which has an external toothing with a rotor trained cylinder block 8 is connected. In which illustrated embodiment are in the cylinder block 8 eight cylinder bores 10 formed in which a piston 12 is guided radially displaceable. Between the radially inner piston crown 14 and the The bottom of the cylinder bore 10 is a cylinder space 16 limited, can be fed into the pressure medium. To the end portion of each piston distant from the cylinder space 16 12 is a roller 18 which is supported during the rotational movement of the cylinder block 8 on a cam 20 of the lifting ring 4.

As can be seen from the illustration according to FIG the control cam 20 with 6 radially projecting control cams 22 executed. When starting up on these control cams 22, the pistons 12 are radially inward Moved towards their dead center. Between two adjacent control cams 22 are each a valley 24 trained so that the piston 12 in the apex of the Valleys 24 are at their outer dead center, in which the Cylinder space has its maximum volume.

Each of the cylinder spaces 16 is one in the cylinder block 8 trained tax breakthrough 26 assigned by the pressure medium supplied depending on the piston position or is dissipated. In the illustrated embodiment are eight control breakthroughs according to the number of pistons 26 distributed on a pitch circle around the circumference.

In the illustration according to Figure 1 is behind Plane lying and inserted into the housing 2 Control housing 30, which is covered by the cylinder block 8 is only dashed with its inner and outer circumference shown. In this control housing 30 are inlet and drain channels 32, 34 formed in the Representation according to Figure 1 also only dashed are indicated. According to the number of control cams 22 each have six inlet channels 32 and six drain channels 34, which alternately evenly a pitch circle are distributed, the diameter of which of the pitch circle of the control cross sections 26 corresponds. In the representation according to FIG. 1, it should be noted that that the 45 ° to the horizontal or vertical muzzle cross sections of the inlet and outlet channels 32, 34 by those shown with a solid line Tax breakthroughs 26 are covered.

The inlet channels are open to a first ring channel, the radially between the control housing 30 and is the housing 2 and with an inlet connection on Housing 2 is connected, and the drain channels 34 are open to a second ring channel that extends axially to the first Ring channel spaced, also radially between the Control housing 30 and the housing 2 is located and with a Drain connection on the housing 2 is connected.

Depending on the design, the Tax breakthroughs 26 and / or the mouth cross sections the inlet and outlet channels 32, 34 as axial bores in Cylinder block 8 or in the control housing 30 only indicated or else - similar to the ones mentioned in the introduction Embodiments described in EP 0 263 218 A1 - in Control discs are located on the cylinder block 8 or the control housing are put on and by each only the front mouth areas of the assigned Channels are formed. Such the mouth cross sections training control disks are easier can be manufactured as bores or cutouts in the housing 2 or in the cylinder block 8.

FIGS. 2 and 3 show the geometric relationships of a control breakthrough 26 and the associated opening cross section of an inlet and an outlet channel 32, 34. As already mentioned, the mouth cross-sections 36, 38 of the channels 32 and 34 as well as the control openings 26 are designed with an identical geometry, which is described with reference to FIG. 3. In this exemplary embodiment shown, the end face sections 40, 42 arranged diametrically to one another in the radial direction are each designed with a radius of curvature r ₂ or r ₁ , the radius of curvature r _{2 of} the radially outer end face section 40 being greater than the radius of curvature r _{1 of} the radially inner end face section. In the limit case, both end faces 40, 42 can be designed with identical radii r.

The connecting the two end face portions 40, 42 Side surfaces 44 are in the in Figures 2 and 3 illustrated embodiment as tangential surfaces to the end face portions 40, 42, wherein these tangential planes face each other in the radial direction arranged symmetry plane 48 meet. This intersection of the two tangent planes can, for example, in the axis of the output shaft 6.

Such a breakthrough 26 (32, 34) is extreme easy to manufacture because, for example, the two end face sections 42, 40 formed by bores and then the tangential surfaces 44, 46 can be manufactured by milling or the like.

As can be seen in particular from FIG. 2, the Geometries and the distance between two neighboring cross sections 36, 38 selected such that in the illustrated Relative position in between is a tax breakthrough 26 can be arranged with zero coverage. The side surfaces 44, 46 are in this relative position of the control breakthrough 26 in the axial direction the adjacent side faces of the adjacent mouth cross sections 36, 38 arranged. That is, the one in this Relative position is neither a pressure medium supply nor a pressure medium discharge to or from the assigned Cylinder chamber 16.

If the tax breakthrough is rotated further 26 relative to the mouth cross sections 36, 38 is through the comparatively long side surface 44 or 46 of the Tax breakthrough 26 very quickly a large cross section of the inlet or outlet channel 32, 34 turned on, so that the flow losses when reversing are minimal.

FIG. 4 shows a simplified exemplary embodiment, in which the production outlay for the control breakthroughs 26 or the mouth cross sections 36, 38 is further minimized compared to the previously described exemplary embodiment. In the control breakthrough 26 shown by way of example in FIG. 4, the end face sections 40, 42 are formed by two bores with the radius r ₁ and r ₂ , similarly to the above-described exemplary embodiment. The axial distance d between the two bores is less than the sum r ₁ + r ₂ , so that the two bores overlap one another. The result is an approximately eight-shaped mouth cross section, the inwardly projecting side surfaces not being reworked as in the exemplary embodiment described above. In this simplified exemplary embodiment, the simplified manufacture is purchased with a slower opening and closing of the inlet and outlet channels 32, 34.

Taper in the above-described embodiments the control breakthroughs 26 in the radial direction towards the axis of the radial piston motor. Figures 5 and 6 show two further variants of a tax breakthrough 26, which is even simpler than the solutions described above can be produced.

In the exemplary embodiment shown in FIG. 5, the control breakthrough 26 is carried out, similarly to the exemplary embodiment described with reference to FIG. 4, by two overlapping bores with the diameter r ₁ = r ₂ . The overlap of the two holes requires that the distance d is smaller than the dimension 2 r ₁ (2 r ₂ ). This variant can be produced, for example, in a simple manner by drilling, with no reclamping of the drill as in the exemplary embodiment shown in FIG. 4 being necessary.

FIG. 6 finally shows an exemplary embodiment in which the end face sections 40, 42 are likewise made through two bores with the diameter r ₂ = r ₁ . In this variant, the distance d between the two bore centers is greater than the sum of the two radii 2 r ₁ (2 r ₂ ), so that there is no overlap area. The two bore sections are then connected, as in the embodiment shown in FIG. 3, by tangentially extending side surfaces 44, 46, so that there is practically an elongated hole whose width is equal to the diameter r ₁ . In other words, in the variants shown in FIGS. 5, 6, the control breakthroughs 26 are therefore not tapered in the radial direction.

Of course, the cross sections described above also by processing methods other than Drilling, such as milling, wire EDM or EDM getting produced.

The area of the opening cross-sections can be determined by suitable Choice of the distance d between the end face sections adapted to different requirements be, the or the hole diameter practical remain unchanged so that zero coverage is guaranteed is.

A radial piston machine with several, radial pistons guided in a cylinder space, the cylinder rooms via control breakthroughs with inlet or drainage channels for pressure medium can be connected. The mouth cross-sections of the tax breakthroughs and the Inlet and outlet channels are with curved end face sections Mistake.

Claims (8)

1. A radial piston machine having a cylinder block (8) which is mounted in a housing (2) and in which a multiplicity of pistons (12) guided in cylinder spaces (16) and supported on a cam ring (4) are mounted, and having a multiplicity of cylinder block-side control recesses (26) capable of being made to coincide with opening cross-sections (36, 38) of housing-side supply and drain passages (32, 34) in order to control supply and drain, wherein the control recesses (26) and/or the opening cross-sections (36, 38) have curved end face portions (40, 42) and a greater longitudinal dimension in the radial direction than in the transverse direction, characterized in that the end face portions (40, 42) are formed by two bores.
2. A radial piston machine in accordance with claim 1, wherein the mean radius of curvature (r₂) of the radially outer end face portion (40) is greater than that of the inner end face portion (42).
3. A radial piston machine in accordance with claim 1 or 2, wherein the centers of curvature are spaced apart from each other by less than the sum of the radii of curvature (r₁ + r₂) of the bores.
4. A radial piston machine in accordance with any one of the preceding claims, wherein the end face portions (40, 42) are interconnected by lateral surfaces (44, 46) extending approximately tangentially thereto.
5. A radial piston machine in accordance with any of claims 1 to 3, wherein the control recesses (26) and/or the opening cross-sections (36, 38) are only formed by two bores.
6. A radial piston machine in accordance with any one of the preceding claims, wherein the geometries of the control recesses (26) and of the opening cross-sections (36, 38) are identical.
7. A radial piston machine in accordance with any one of the preceding claims, wherein the control recesses (26) and/or the opening cross-sections (36, 38) are each formed on a cam disc fixed at the end face side on the cylinder block (8) and on the housing (2), respectively.
8. A radial piston machine in accordance with any one of the preceding claims, wherein the control recesses (26) and the opening cross-sections (36, 38) are formed with zero overlap.

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