CS202196B1 - Press cylinder of the axial hydrostatic converter - Google Patents

Description

It is an object of the present invention to provide a working wall of an axial piston hydrostatic transducer with a pivot plate.

When operating the axial hydrostatic transducer with the pivot plate in the high pressure range, large transverse forces act on the piston, causing undesirable frictional forces between the piston and the cylinder. Similarly, at high piston speeds, high frictional forces occur between the piston and cylinder, even with the highest quality lubricating film. By creating supporting hydrostatic and hydrodynamic pressure fields, it is possible to achieve a reduction of these frictional forces at low values of the product μ ω

Pa where: μ - liquid viscosity ω - angle of rotation of cylinder block p _a - working pressure of liquid

Favorable results in the overall reduction of frictional losses between the piston and the cylinder are also achieved by avoiding frictional contact between the friction surfaces. According to the state of the art, the supporting pressure fields are artificially formed by supplying pressurized oil to the shaped recesses formed in the cylindrical flat piston or barrel, either throttled from the working space of the barrel, or by a special manifold having a pressure higher than the working pressure in the cylinder. . A common disadvantage of such devices is their structural complexity and the resulting manufacturing complexity. The edge pressures can be reduced to a limited extent by reducing the radial clearance between the piston and the cylinder. Excessive reduction of the radial dude, however, results in an increase in the frictional losses expressed by:

h where: F _T - friction force,

S - friction surface, v - relative speed and h distance of friction surfaces.

Another generally valid way of reducing edge pressures is to reduce the radial stiffness of the radial bearing ends.

Disadvantages of the prior art are reduced by the working cylinder of the axial hydrostatic transducer formed from the bushing embedded in the block of rolling stock according to the invention, the principle being that the guide surface consists of two coaxial cylindrical surfaces of the same diameter formed in the bushing. the guide surface y is separated from the second guide surface by a shaped recess, into which a supply channel connected to the working space of the valle flows.

The advantage of the axial hydrostatic transducer working cylinder according to the invention is that in a simple conversion operation, the piston-cylinder pair ensures low frictional loss work, especially for high working pressures and speeds, which are reasonably low at a relatively large radial damp production tolerance. between the piston and the cylinder, which eliminates the need for pairing.

The attached drawing shows an exemplary embodiment of a working cylinder of an axial hydrostatic converter according to the invention. 1 is a longitudinal section through the cylinder; and FIG. 2 is a partial cross-section of the cylinder.

The working cylinder of the hydrostatic axial transducer consists of a bush 1 which is pressed in the cylinder block 2. In the housing 1, a first guide surface 11 of L3 length and a second guide surface 12 of L1 length are formed, which are separated by a shape recess 13 of L2 length. In the first vo. By means of a flat 11, a threaded groove 14 is formed which connects the space of the shape recess 13 with the working space 21 of the cylinder. A conical chamfer at the front end thereof is transferred to the outer flat housing 1 at its front end, and a conical run of the length L s is converted into the housing bore 1. ·

When the transducer is operating at the working pressure p _a , the transverse force F 'applies at the end of the piston 3. This

Claims (3)

An axial hydrostatic transducer working cylinder formed from a housing mounted in a cylinder block, characterized in that the guide surface of the cylinder consists of two coaxial cylindrical surfaces of the same diameter formed in the housing (1), the first guide surface (11) being separated from a second guide surface (12J) by a shaped recess (13) into which a feed channel (14) communicating with the working space (21) of the cylinder opens. Working roll according to claim 1, characterized in that the supply channel (14) is formed by a threaded groove in the first guide flat (11). A method jam of the power piston 3, which then contacts the guide surface of the casing 1 mainly at points 4 and 3, wherein the greater load being applied to the fourth feeding ducts 14 into the shaped recess 13 brings the liquid, the pressure p _and the same as that fluid in the cylinder working space 21. The course of the liquid pressure on the second guide flat 12 will be characterized by curves 6 and 7, the curve 7 characterizing the course of the pressure in the area of the force contact of the piston 3 with the sleeve 1. By supplying the pressure fluid to the recess 13. to increase the load-bearing capacity of the oil film and to create a balancing hydrostatic force proportional to the flat confined by lines 6 and 7, near the force contact point 4. Due to the shape adjustments of the housing 1 and the hole for its pressing in the lengths L4 and 1.5, there is an elastic deformation at the points 4 and 3 of the force contact of the piston 3 with the housing 1, thereby reducing the loading of the oil film. at these points and the weekly risk of oil film interruption is reduced. For comparison, FIG. 1 further shows a line 9 which indicates the course of pressure at smooth and coaxial of the piston with the cylinder. invention 3. The work roll according to claim 1, characterized in that the sleeve (1) has at least at one end a reduced outer diameter in the length (L4) and the sleeve opening (1) formed in the block (2) has a taper at the inlet. The length of the length (L4) as well as the length (Ls) is in the range of ten to twenty percent of the working diameter of the roll.