DE102014116381A1 - Hydrostatic radial bearing - Google Patents

Abstract

The invention relates to a hydrostatic radial bearing (103) with two sliding partners (105, 107) which are spaced apart from each other by a bearing gap (109) and a lubricant arranged between the sliding partners (105, 107). At least one of the two sliding partners (105, 107) is elastically deformable for adjusting the bearing gap (109). As a result, the bearing gap (109) can be controlled via the system pressure that is being established. With the invention, in particular, large components such as support tubes or shafts (115) can be manufactured and exchanged much more easily.

Description

The invention relates to a hydrostatic radial bearing with two sliding partners, which are spaced from each other by a bearing gap, and a lubricant arranged between the sliding partners.

Hydrostatic bearings are used because of their very high accuracy and freedom from wear, for example in high-precision applications. The bearing surfaces are always separated by a thin lubricating film of a lubricant, which is usually introduced via inlet channels into chambers between the bearing surfaces. Hydrostatic bearings require very small gaps. The gap may also vary only within small limits, so that even at low rotational speeds for which this type of storage is particularly suitable, especially when changing from the stationary to the moving state and vice versa, no mixed friction occurs.

These small tolerances make the production of the sliding, especially for long support sections of the camp, before major challenges. As a result, elaborate and highly precise manufacturing processes are generally required. In addition, the sliding partners are made as a pairing, which makes the replacement of individual sliding partners difficult or possibly impossible.

Bearings whose bearing gaps are adjustable are known in the art. For adjusting the bearing clearance for rolling bearings is in DE 43 34 878 A1 provided to deform the shaft of the bearing by means of a hydraulic medium.

DD 241 106 describes a hydrostatic radial-axial bearing in which in the thrust bearings temperature-induced changes in length are compensated by spring preloads, while the radial bearings remain unaffected.

FR 1 355 328 A1 discloses a hydrodynamic bearing in which a bearing bush is elastically deformed by means of screws and thus the bearing gap is adjustable.

Object of the invention

The object of the invention is to improve the prior art and in particular to provide a hydrostatic radial bearing, which is manufacturable with relatively little effort and its sliding partners are interchangeable.

The object is achieved by a hydrostatic radial bearing with two sliding partners, which are spaced apart from each other by a bearing gap, and a lubricant arranged between the sliding partners, wherein one of the two sliding partners for adjusting the bearing gap is elastically deformable.

The deformation of one of the two or both sliding partners ensures that there is always a sufficient lubricant layer between the sliding partners and no mixed friction occurs. There are therefore no exactly manufactured to each other sliding partners required because of the length or the extent of changing gap spacing can be compensated by an elastic expansion.

The bearing gap is preferably changed in the range of hundredths of a millimeter or microns. Due to the elastic deformability of at least one of the sliding partners can be dispensed with very expensive, high-precision manufacturing process for the sliding, and it can be used on a more cost-effective production technology for the sliding partners. A pair of sliding partners is thus unnecessary, so that they need not be made only as two only matching each individual pieces, but are mutually interchangeable at least in parts. Depending on the production technology, one or more post-processing steps of the sliding partners can also be dispensed with, which further simplifies their production.

In one embodiment, adjusting the bearing gap is solely or partially via the system pressure of the lubricant. To widen the bearing gap, the lubricant is introduced into the bearing gap at a sufficiently high pressure.

In a further embodiment, additionally or exclusively, an elastic deformation of at least one of the sliding partners takes place via an external means such as a clamping set.

The adjustment of the required bearing gap can be controlled indirectly via the system pressure of the lubricant. For this purpose, a device may be provided with a radial bearing according to the invention with a pressure measuring device. The system pressure can be controlled or regulated by a control unit depending on the load, the speed, the lubricant, the temperature and the other external conditions.

Furthermore, one of the sliding partners may be formed as a bushing and the other sliding partner as a shaft. The shaft is at least partially enclosed by the socket. It is therefore not necessary that the bush surrounds the shaft over its entire axial length, but only in the region of the bearing. In the circumferential direction, the shaft and the socket have matched, circular cylindrical contours.

The shaft can be configured as a solid or hollow shaft. The material forming the jacket of a hollow shaft can be made so thin-walled, that the hollow shaft forms the sliding partner, which is deformable. The shaft can be designed as a linearly movable support tube and additionally supported axially.

In particular, it is the bush which is deformed according to the invention. For this purpose, this is usually formed to its elastic and reversible, non-permanent deformation thin-walled, for example as a metal sleeve.

The bush can be a one-piece pipe section, but this can also be composed of several pipe section segments, which optionally also allows a localized deformation. The bush can also be provided with an inner contour, the distance to the cylinder axis over a partial circumference, the entire circumference, over an axial length or over the entire length of the socket is variable.

For this purpose, it can be pressurized in an embodiment at discrete locations from the outside and / or acted upon by a back pressure. In the simplest case, it is formed by a cylindrically symmetrical hollow tube which receives the shaft in its interior and is optionally provided with individual pockets or lubricant bushings.

In a further development, the bushing can be changed in its diameter by means of a clamping set. The clamping set can be designed as a hydraulically acting clamping bush, in which a hydraulic fluid is compressed in a closed space.

Alternatively, clamping devices are provided which can act on the socket from the outside. One possibility of a clamping device is a wedge slope, over the movement of which the bushing can be applied continuously in a region with a stronger force. For this purpose, a self-centering cone clamping element can be used with central clamping nut.

Another way to vary the socket diameter, it is to set up a pressure sleeve with a rectangle signal in longitudinal section-like profile on the socket. Upon application of an axial pressure on the pressure sleeve, the inner profile sections of the meandering shell exert a pressure deforming the bushing.

The bushing is preferably uniformly deformed over its entire circumference and over its entire axial length.

In another embodiment, the deforming forces act only locally. In particular, in the case of axially long bushings, a plurality of clamping sets are provided, which deform the bush in sections, in order to compensate for any diameter fluctuations of the shaft.

As a lubricant liquids or gases can be provided. Preferably, an adapted to the planned environmental conditions, the tribology optimizing hydraulic medium, usually a special oil used.

The radial bearing according to the invention is preferably used in machine tools.

The invention is particularly suitable for complex and elaborately constructed machines whose components are exposed to wear. Due to the adjustability of the bearing gap between the two sliding partners surface deviations of the individual sliding partners can be sufficiently compensated so that they are individually interchangeable.

Description of the drawings

Furthermore, the invention will be explained with reference to exemplary embodiments. Show it

1 a schematic partial longitudinal section of a first device with a hydrostatic radial bearing,

2 a schematic partial longitudinal section of a second device with a hydrostatic radial bearing,

3 a schematic representation of the radial bearing after 2 and

4 an enlarged schematic partial representation of the radial bearing after 2 ,

1 shows together with the 2 to 4 a device 101 with a hydrostatic radial bearing 103 ,

The radial bearing 103 has two sliding partners 105 and 107 on, of which the first as a wave 115 is trained. The wave 115 is about the axis of rotation 111 rotatable and represents a linearly movable support tube. The shaft 115 has a length corresponding to a multiple of its diameter and is radially mounted at various locations. Radial from the shaft 115 are not detailed structures 113 the device 101 arranged.

The second sliding partner 107 hydrostatic radial bearing 103 has a socket 117 on. The socket 117 is changeable in its inner diameter, by means of clamping devices 119 a pressure is exerted on this. To maintain the fluid friction is the on the clamping devices 119 applied pressure chosen so that a bearing gap 109 defined height sets. The clamping devices 119 are part of a clamping set or a wedge slope.

In the storage gap 109 is an oil as a lubricant.

During operation of the device, the system pressure is determined via a pressure measuring device, not shown, in order to conclude indirectly from this to the desired bearing gap width or to change this regulating or controlling.

In the storage gap 109 the oil is introduced via pockets, also not shown. Because the bearing gap 109 over the clamping devices 119 is adjustable, the pumps and chokes required for the oil can be adjusted accordingly.

LIST OF REFERENCE NUMBERS

101

 contraption

103

 hydrostatic radial bearing

105

 first sliding partner

107

 second sliding partner

109

 bearing gap

111

 axis of rotation

113

 construction

115

 wave

117

 Rifle

119

 clamping device

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

• DE 4334878 A1 [0004]
• DD 241 106 [0005]
• FR 1355328 A1 [0006]

Claims (9)

Hydrostatic radial bearing ( 103 ) with two sliding partners ( 105 . 107 ) passing through a bearing gap ( 109 ) are spaced apart, and one between the sliding partners ( 105 . 107 ) arranged lubricant, characterized in that one of the two sliding partners ( 105 . 107 ) for adjusting the storage gap ( 109 ) is elastically deformable. Radial bearing according to claim 1, characterized in that the setting of the bearing gap ( 109 ) over the system pressure of the lubricant. Radial bearing according to claim 1 or 2, characterized in that one of the sliding partners ( 107 ) as a socket ( 117 ) and the other sliding partner ( 105 ) as a wave ( 115 ) coming from the socket ( 117 ) is at least partially enclosed, is formed. Radial bearing according to claim 3, characterized in that the shaft ( 115 ) is formed as a linearly movable support tube. Radial bearing according to claim 3 or 4, characterized in that the bushing ( 117 ) is provided with an inner contour whose distance from the cylinder axis ( 111 ) over a partial circumference, the entire circumference, over an axial partial length or over the entire length of the bushing is variable. Radial bearing according to one of claims 3 to 5, characterized in that the bushing ( 117 ) is compressible by means of a clamping set. Radial bearing according to one of claims 3 to 5, characterized in that the bushing ( 117 ) is compressible by means of a wedge slope. Contraption ( 101 ) with a hydrostatic radial bearing ( 103 ) according to one of the preceding claims, characterized in that the device ( 101 ) has a Gleitmitteldruckmesseinheit to the setting of the storage gap ( 109 ) to control. Contraption ( 101 ) with a hydrostatic radial bearing ( 103 ) according to any one of claims 1-8, characterized in that the device ( 101 ) as a machine tool with a replaceable shaft ( 115 ) as one of the sliding partners ( 105 ) is trained.

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