DE102018205447A1 - Piston for a hydrostatic axial piston machine - Google Patents

Abstract

Disclosed is a piston for a hydrostatic axial piston machine with a plurality of circumferentially distributed preferably inclined recesses, which are preferably formed by long blind holes.

Description

The invention relates to a piston for a hydrostatic axial piston machine according to the preamble of patent claim 1.

In the case of pistons for axial piston machines, solid pistons are known, whose circular-cylindrical main section and spherical piston foot are in one piece and consist of solid material. The piston foot serves to form a ball joint. The circular-cylindrical main section is guided in a respective cylinder bore of a rotating cylinder drum, while the piston foot is coupled to an inclined disc or to an inclined shaft flange of the axial piston machine.

Pistons are also known which have an open cylinder bore and thus to the pressure side concentric blind hole, which is filled with pressure medium in operation of the affected axial piston machine.

In the publication US 9,593,774 B2 various pistons for an axial piston machine are disclosed, which have a plurality of eccentric pressure-tight air chambers, which extend substantially over the length of the circular cylindrical main portion of the respective piston.

The publication US 6,274,083 B1 shows a piston for an axial piston machine with two eccentric elongated recesses extending largely over the length of the circular cylindrical main portion of the piston. The recesses do not penetrate the cylinder bore facing the piston head side of the piston. On the piston foot side or ball joint side of the main portion, however, the two elongated recesses are open and there each have a curvature.

A disadvantage of such piston for an axial piston machine is their production cost.

In contrast, the invention is based on the object to provide a piston for an axial piston machine, which has a reduced weight with reduced Fertigungsauswand.

This object is achieved by a piston having the features of patent claim 1.

Further advantageous embodiments of the invention are described in the dependent claims.

The claimed piston is designed for use with a hydrostatic axial piston machine and has a plurality of longitudinal recesses. These extend from a piston-foot-side or ball-joint-side side or end face of a main section, to which a piston foot for a ball joint is also attached, into the interior of the main section. The longitudinal recesses preferably extend largely through the main section. According to the invention, the longitudinal recesses have a continuous circular cylindrical shape. Thus, the kolbenfußseitigen end portions of the longitudinal recesses have the circular cylindrical shape without curvature and thus are easier to produce than the recesses of the prior art.

Preferably, the longitudinal recesses are distributed uniformly on the circumference of the main section or of the piston.

The weight saving of the piston is particularly high when the longitudinal recesses extend over more than 80%, preferably over more than 90% of the length of the main portion towards a piston head of the piston or main portion.

The weight saving is higher than in the prior art, if at least three longitudinal recesses are provided.

The weight saving is particularly high with 10 to 14 e.g. 12 longitudinal recesses.

The production of the longitudinal recesses is simplified if they are employed obliquely to a longitudinal axis of the piston.

The production is particularly simplified if the piston bottom side end portions of the longitudinal recesses are closer to the longitudinal axis than kolbenfußseitige end portions of the longitudinal recesses.

The longitudinal recesses can be employed by 2 ° to 5 °, preferably 3.5 °.

The weight saving is correspondingly high when the longitudinal recesses 17-23% e.g. Make up 20% of the volume of the entire flask.

The production he longitudinal recesses is particularly simplified if they are deep blind holes.

In this case, the piston bottom side end portions of the blind hole bores corresponding to the drill used, for. be cone-shaped.

An embodiment of a piston according to the invention for an axial piston machine is shown in the figures.

• 1 den erfindungsgemäßen Kolben gemäß dem Ausführungsbeispiel in einer perspektivischen durchscheinenden Ansicht auf die kolbenfußseitige Stirnseite,
• 2 den Kolben aus 1 in einer perspektivischen durchscheinenden Ansicht auf die kolbenbodenseitige Stirnseite, und
• 3 den Kolben aus den 1 und 2 in einer seitlichen Ansicht.

Show it

• 1 the piston according to the invention according to the embodiment in a perspective translucent view of the piston foot side end face,
• 2 the piston off 1 in a perspective translucent view of the piston bottom side end face, and
• 3 the piston from the 1 and 2 in a side view.

1 shows the piston according to the invention according to the embodiment in a perspective translucent view of his piston foot end side 1 , The piston has a main section 2 and a piston foot 4 , which can be coupled via a piston shoe to a swash plate of an axial piston machine (not shown). The piston foot 4 is concentric and integral to the piston foot end side 1 of the main section 2 set of the piston.

Between the piston foot 4 and an outer edge of the piston-foot-side end face 1 are even at the circumference 12 deep blind holes 6 provided in each case by the in 1 visible mouth into the interior of the main body 2 extend and thereby about 90 percent of the length of the main section 2 identify.

2 shows the piston 1 in a perspective also translucent view on a piston bottom end side 8th of the main section 2 ,

3 shows the piston of the preceding figures in a side view. This is exemplified by one of the twelve deep blind holes 6 shown that these are starting from the piston foot end side 1 towards the piston bottom side front 8th obliquely with respect to a longitudinal axis 10 of the piston extends. More precisely, the blind holes have 6 opposite to a cross-sectional area 12 of the spherical piston foot 4 an angle a, which may be 93.5 °, for example. So are piston-foot-side end portions of the blind holes 6 further from the longitudinal axis 10 spaced as the piston bottom side end portions of the blind holes 6 , This is a retraction of the (not shown) drill while maintaining a small distance to the piston foot 4 possible.

The piston according to the invention can be used in axial piston machines which are suitable for pressure and suction side changes (free-standing), and an improvement in the high-pressure pulsation is achieved. The purpose of the invention is corner power operation / exhaust for XZG units (FZG / VZG) from a nominal size of 45. Generally, a minimization of the cavitation slope / engine is achieved when it is due to decompression oil.

The piston according to the invention offers a cost-effective dead space volume reduction while at the same time providing a relatively high weight saving. This engine counteractors is counteracted due to significantly higher centrifugal forces in solid pistons.

Disclosed is a piston for a hydrostatic axial piston machine with a plurality of circumferentially distributed preferably inclined recesses, which are preferably formed by long blind holes.

LIST OF REFERENCE NUMBERS

1

piston foot side

2

main section

4

piston base

6

Blind hole

8th

piston-bottom side

10

longitudinal axis

12

Cross sectional area

α

angle

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

• US 9593774 B2 [0004]
• US 6274083 B1

Claims (9)

Piston for a hydrostatic axial piston machine, wherein the piston has a plurality of longitudinal recesses (6) extending from a piston base end face (1) of a main portion (2) inside the main portion (2), characterized in that the longitudinal recesses (6) has a continuous circular cylindrical Have shape. Piston after Claim 1 , wherein the longitudinal recesses (6) extend over more than 80% of a length of the main section (2). Piston according to one of the preceding claims with at least three longitudinal recesses (6). Piston according to one of the preceding claims with 10 to 14 longitudinal recesses (6). Piston according to one of the preceding claims, wherein the longitudinal recesses (6) are made oblique to a longitudinal axis (10) of the piston. Piston after Claim 5 in which piston-bottom-side end sections of the longitudinal recesses (6) are closer to the longitudinal axis (10) than end sections of the longitudinal recesses (6) which are on the piston-leg side. Piston after Claim 5 or 6 , wherein the longitudinal recesses (6) are employed by 2 ° to 5 ° to the longitudinal axis (10). Piston according to one of the preceding claims, wherein the longitudinal recesses (6) constitute 17 - 23% of a volume of the entire piston. Piston according to one of the preceding claims, wherein the longitudinal recesses (6) are deep blind holes.

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