DE102009044640A1 - Portal-type coordinate measuring device, has table movable in linear movement axis of device and comprising transducer for detecting position of table in movement axis, where transducer arranged in rotational axis of turntable - Google Patents

Abstract

The device (1) has a table (3) movable in a linear movement axis of the device and comprising a transducer for detecting a position of the table in the movement axis. The transducer is arranged in a rotational axis of a turntable (11), and the table is arranged on a base plate (2) in a linearly movable manner. A linear material measure is arranged at the base plate, and the transducer has a reading head for reading the material measure. The table is movably supported on the base plate by three bearings such as air bearings.

Description

The The invention relates to a coordinate measuring machine with a in a linear movement axis of the coordinate measuring machine movable table with a turntable and with at least one Transducer for detecting the position of the table in the movement axis, wherein the turntable has an axis of rotation.

Out In practice, a coordinate measuring machine is known in which a table with a turntable arranged in or on the table in a linear movement axis of the coordinate measuring machine is movable. The coordinate measuring machine has a basic bed on, on which the table is movable. To capture the position The table with integrated turntable is in the edge area of the table at least one transmitter provided with the aid of an am Basic bed attached scale the position of the table recorded in the coordinate system of the measuring machine. The place of attachment of the transmitter is usually used on the basis of accessibility Edge of the table chosen because the transmitter in his spatial reference to scale must be adjusted.

Especially Measurements in the production area are subject to the coordinate measuring machines very high temperature fluctuations of, for example, up to 15 ° Celsius. These temperature fluctuations are noticeable that is the main body of the coordinate measuring machine as well as the movable table expand or contract. This changes the distance between the transmitter and the axis of rotation of the On the mobile table arranged turntable, what a virtual Displacement of the turntable axis in the coordinate system of the measuring machine entails. As a result, measurement errors occur because the axis of rotation of the turntable when converting coordinates of the coordinate system the measuring machine in workpiece coordinates on the turntable is suspected in the wrong place.

The prior art ( U.S. Patent 4,631,834 ) includes a coordinate measuring machine in gantry design, which has a table for receiving a workpiece. Below a workpiece support surface, a transmitter is arranged.

Furthermore belongs to the state of the art ( DE 37 33 617 A1 ) a multi-coordinate measuring machine having a movable table for receiving a workpiece. According to one embodiment, a turntable is additionally arranged in the movable table.

This Prior art coordinate measuring machine has the disadvantage described above, that in case of temperature fluctuations the main body of the coordinate measuring machine as well expand or contract the moving table and that yourself As a result, the distance between the transmitter and the axis of rotation of the on the movable table arranged turntable changes, whereby measurement errors occur.

The The technical problem underlying the invention is that specify a coordinate measuring machine with a turntable, where the mentioned disadvantages do not occur.

The Coordinate measuring machine according to the invention with a in a linear axis of movement of the coordinate measuring machine movable table with a turntable and with at least one Transducer for detecting the position of the table in the movement axis, in which the turntable has an axis of rotation characterized by from that arranged the at least one transmitter in the axis of rotation is.

By this arrangement of the at least one transmitter in the axis of rotation The turntable ensures that the transmitter regardless of temperature fluctuations and their dependent Extentions of the table the position of the table by means of the linear Measurements captured and thus the position the turntable axis is determinable. This minimizes measurement errors.

According to one Another embodiment is the at least one transmitter arranged below the turntable or within the turntable. In principle, it is also conceivable to use the measuring sensor above a Wertstückauflageflä surface of the turntable, for example, to arrange with suitable tools.

According to one further advantageous embodiment of the invention has the coordinate measuring machine on a basic bed on which the Table with the turntable is arranged linearly movable. To the Basic bed is arranged a linear measuring scale. The at least one transmitter has a read head for reading the linear measuring standard. As a result of that the reading head in orthogonal direction below the turntable is advantageously arranged in the axis of rotation of the turntable are minimizes measurement errors.

The arrangement of the at least one transmitter within the turntable or below the turntable has the advantage that the at least one transmitter is arranged in the vicinity of the linear measuring graduation, so that with the transmitter, if it has a read head for reading the linear measuring scale, un indirectly, the measured values can be recorded.

Advantageous is the linearly movable table by means of at least three bearings movably mounted on the basic bed. These bearings are advantageous designed as an air bearing. There is also the possibility to use other suitable bearings.

In a particularly preferred embodiment is the table with the help of four laterally arranged on the table air bearings laterally guided.

in this connection is the linearly movable table by means of the four air bearings laterally guided on guide surfaces of the basic bed, and each guide surface are each two air bearings one assigned as a fixed bearing and the other as a floating bearing is executed and each bearing of a guide surface the Floating bearing of the other guide surface opposite.

in this connection Under fixed storage is understood a rigid bearing, which in the direction the bearing force is rigidly connected to the movable table while the floating bearing in the direction of the bearing force is soft and ideally can only exert a force without rigidity.

The Fixed bearings have a high rigidity in the direction of the bearing force on while the non-locating bearings, or spring bearings called, ideally have a stiffness equal to zero and only exert a force that the fixed bearings as bias serves to put them in a stiff working point.

Further Features and advantages of the invention will become apparent from the associated Drawing in which an embodiment of an inventive Coordinate measuring device is shown only as an example. In the drawing show:

1 a coordinate measuring machine in gantry design in perspective view;

2 a table mounted on a basic bed in perspective view, partially cut.

1 shows a coordinate measuring machine 1 in portal construction with a basic bed 2 on which a table 3 Is arranged displaceably in X-Rich direction. These are guides 4 on the basic bed 2 arranged. A portal 5 which supports 6 has and which is not designed to be displaceable, contributes to a traverse 7 a slidable in the Y direction slide 8th , on which in turn in the Z direction displaceable quill 9 is arranged. The quill 9 carries a probe 10 , to which in turn a probe combination (not shown) can be arranged.

In the table 3 is a turntable 11 arranged on which a workpiece (not shown) can be arranged.

2 shows the table 3 with the turntable 11 , The turntable 11 can perform a rotational rotary motion in the direction of the double arrow A. The turntable 11 has a rotation axis B on. In the axis of rotation B is a transmitter 12 having a reading head (not shown) arranged. By means of the transmitter 12 is the detection of the exact position of the table 3 with the help of one on the basic bed 2 arranged linear measuring standard 13 possible. Because of the transmitter 12 in the axis of rotation B, that is below the turntable 11 is arranged, the exact position of the axis of rotation B can be determined independently of occurring temperature fluctuations with consequent material expansions or a contraction of the material of the table 3 ,

The table 3 is in the usual way with bearings 14 on the basic bed 2 movably mounted in the direction of the double arrow C.

The turntable 11 has a workpiece support surface 15 on which a workpiece (not shown) can be arranged.

1

coordinate measuring machine

2

basic bed

3

table

4

guide

5

portal

6

Support

7

traverse

8th

carriage

9

Pinole

10

probe

11

turntable

12

Transmitters

13

linear Measuring standard

14

camp

15

Workpiece support surface

A

double arrow

B

axis of rotation

C

double arrow

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 4631834 [0004]
• - DE 3733617 A1 [0005]

Claims (5)

Coordinate measuring machine with a movable in a linear axis of movement of the coordinate measuring machine table with a turntable and at least one transmitter for detecting the position of the table in the movement axis, wherein the turntable has an axis of rotation, characterized in that the at least one transmitter ( 12 ) in the axis of rotation (B) of the turntable ( 11 ) is arranged. Coordinate measuring machine according to claim 1, characterized in that the at least one transmitter ( 12 ) within the turntable ( 11 ) or below the turntable ( 11 ) is arranged. Coordinate measuring machine according to claim 1 or 2, characterized in that the coordinate measuring machine ( 1 ) a basic bed ( 2 ) on which the table ( 3 ) with the turntable ( 11 ) is linearly movable, and that at the base bed ( 2 ) a linear measuring standard ( 13 ), and that the at least one transmitter ( 12 ) a read head for reading the linear measuring standard ( 13 ) having. Coordinate measuring machine according to one of the preceding claims, characterized in that the linearly movable table ( 3 ) by means of at least three bearings ( 14 ) on the basic bed ( 2 ) is movably mounted. Coordinate measuring device according to claim 4, characterized characterized in that the linearly movable table by means of four Air bearing laterally on guide surfaces of Grundbet TES is guided, and that every guide surface each two air bearings are assigned, one of which as a fixed bearing and the other is designed as a floating bearing, and that everyone Fixed bearing of a guide surface, the floating bearing the other guide surface is opposite.