Coordinate measuring machine

Abstract

A coordinate measuring machine (10) includes: a component (16) movable for measuring the dimensions of an object (14), the component being movably mounted on a guide rail (46) along a longitudinal axis (y); and a driver (40) designed to drive the movable component (16) along the longitudinal axis (y). The driver (40) is at least partially arranged in a groove (54) extending parallel to the longitudinal axis (y) and abutting the guide rail (46) such that a first laterally extending surface (48) of the guide rail (46) forms a first groove side surface (56) of the groove (54). The driver (40) has a motor-driven friction wheel (62) that frictionally contacts the first groove side surface (56) and rolls along the longitudinal axis (y) on the first groove side surface. The driver (40) further has an opposing bearing (78) for supporting the friction wheel (62) and is supported on the second groove side (58) of the groove (54) opposite to the first groove side (56).

Description

Technical Field

[0001] This invention relates to a coordinate measuring machine. Background Technology

[0002] Coordinate measuring machines are well known in the prior art. They are used, for example, as part of quality assurance to inspect workpieces, or entirely as part of so-called "reverse engineering" to determine the geometry of workpieces. Furthermore, a variety of further applications are conceivable.

[0003] Coordinate measuring machines record dimensional measurement data using a measuring head that scans the object being measured in a tactile and / or non-contact manner (e.g., optical). The spatial position and orientation of the measuring head are permanently known during the measurement, so that conclusions about the coordinates of the corresponding contact points on the object can be drawn.

[0004] In addition, this type of coordinate measuring machine typically has a measuring object receiver for receiving the object being measured, which is usually designed as a measuring stage. One or more actuators are used to position the measuring head relative to the measuring object receiver.

[0005] Depending on the design of the coordinate measuring machine (CMM), the measuring head or the object receiving seat, or both, is actively moved by at least one actuator. Movement typically occurs along at least three coordinate axes that are perpendicular to each other. In a so-called cantilever design, the measuring stage, which serves as the object receiving seat, typically moves along one axis, and the measuring head moves along two axes that are perpendicular to each other. In a CMM with a cross-shaped stage design, the measuring stage can move along two axes that are orthogonal to each other, while the measuring head typically moves only along one axis. In bridge, gantry, and column designs, the measuring head can typically move along three axes that are orthogonal to each other, while the object receiving seat, which is also typically configured as the measuring stage, is usually fixed.

[0006] In addition to the linear axes mentioned, coordinate measuring machines according to all the mentioned designs typically have additional rotational axes, which are implemented, for example, through rotary joints connected to the measuring head.

[0007] Linear drives are typically used as drives for linear axes. In the case of the coordinate measuring machine sold by the applicant under the name "Contura", for example, a friction wheel drive with a single-stage belt drive is used to move the gantry (to which the measuring head is secured) relative to the measuring table.

[0008] Such a coordinate measuring machine having a linear drive configured as a friction wheel drive is also known from DE 196 49 252 A1. The friction wheel drive is used here to drive the frame of the coordinate measuring machine with a column design.

[0009] Although such friction wheel drives have proven themselves in practice, they still have drawbacks. In friction wheel drives, the friction wheel presses against a corresponding drive surface. The drive surface must be manufactured with great precision along its entire length (i.e., along the entire travel path) to ensure the high accuracy required by coordinate measuring machines. However, such precise manufacturing of the drive surface is relatively expensive. Furthermore, the guide of the driven component is additionally subjected to the contact pressure of the friction wheel, and errors can occur in this process. Similarly, runout errors in the drive shaft of the drive can cause variations in the contact pressure of the friction wheel, resulting in dynamic loads on the guide of the driven component (e.g., gantry, platform, or bridge).

[0010] Sliding bearings, and particularly preferably air bearings, are typically used to guide and mount driven components. The dynamic changes in the contact pressure of the friction wheel thus cause dynamic changes in the air gap of the air bearing.

[0011] In DE 60 2005 001 565 T2, an attempt was made to absorb these undesirable lateral forces via a tension roller, which serves as the opposing bearing for the drive. A rack and pinion drive is used here as the drive. The disadvantage of this solution is the relatively complex structure required to mount the rack and pinion drive and the tension roller (acting as the opposing bearing) onto the measuring table. Therefore, the drive is constructed relatively high on the measuring table, resulting in a relatively large installation space. Furthermore, the construction consists of a relatively large number of parts. Summary of the Invention

[0012] Therefore, the object of the present invention is to provide a coordinate measuring machine with a drive that has a simple and space-saving design, yet remains stable and has low lateral force.

[0013] According to the present invention, this objective is achieved by a coordinate measuring machine according to claim 1, the coordinate measuring machine comprising:

[0014] - A component that is movable for measuring the dimensions of an object, and the component is movably mounted on the guide rail along the longitudinal axis of the guide rail;

[0015] - A driver designed to drive a movable component along a longitudinal axis;

[0016] The driver is at least partially arranged in a groove that extends parallel to the longitudinal axis and abuts the guide rail, such that a first lateral extending surface of the guide rail forms a first groove side surface of the groove.

[0017] The driver includes a motor-driven friction wheel that frictionally contacts the side of the first groove and rolls along the longitudinal axis on the side of the first groove.

[0018] The actuator further includes a counter bearing for supporting the friction wheel and is supported on a second groove side opposite to the first groove side.

[0019] According to the invention, a friction wheel actuator is therefore used, wherein opposed bearings are used to support the friction wheel and absorb unwanted lateral forces. The opposed bearings are supported on opposite sides of a groove in which the friction wheel of the friction wheel actuator is also arranged. More precisely, the opposed bearings are supported on a groove side (referred to in this case as a "second groove side") opposite to the groove side on which the friction wheel presses against or travels (referred to in this case as a "first groove side"). Therefore, any lateral forces that may arise in the friction wheel actuator can be optimally absorbed.

[0020] In addition, a very space-saving arrangement is achieved because the groove in which the friction wheel and the opposing bearing are arranged directly abuts the guide rail, which is used to guide the movable part driven by the actuator.

[0021] The laterally extending surface (referred to in this case as the "first laterally extending surface" of the guide rail) simultaneously forms the first recessed side of the groove. In other words, the friction wheel rolls directly on the first laterally extending surface of the guide rail. Therefore, the additional structure proposed in DE60 2005 001 565 T2 is unnecessary. Compared to this solution, the actuator according to the invention can therefore be implemented in a significantly more space-saving manner and with fewer parts.

[0022] Furthermore, incorporating the friction wheel actuator into a groove adjacent to the guide rail offers advantages in terms of stability and manufacturing. The groove, along with the guide surface for guiding the movable part and the drive surface for the friction wheel, can thus be directly integrated into the measuring table of a coordinate measuring machine. This not only allows for relatively simple production but also results in an extremely stable or robust structure, resistant to vibration, and can be manufactured with relatively high precision.

[0023] Therefore, the above objectives have been fully achieved.

[0024] According to one configuration, the side surfaces of the first groove and the second groove are oriented parallel to each other.

[0025] In other words, the groove preferably has a rectangular or U-shaped cross-section. The advantage of parallel groove sides is that the lateral force of the friction wheel drive can be optimally compensated by means of opposed bearings, since the friction wheel and the opposed bearings act on surfaces that are positioned relative to each other and oriented parallel to each other.

[0026] According to another configuration, the movable component has a guide carriage that is movably mounted on a guide rail along a longitudinal axis and is at least partially arranged in a groove.

[0027] The lateral sides of the guide carriage preferably protrude into the groove. This further saves space because not only the friction wheel drive and the opposed bearing are arranged in the groove, but also a portion of the guide carriage is arranged in the groove.

[0028] According to another configuration, the guide carriage has: a first guide bearing for guiding on a first lateral extension surface of the guide rail; a second guide bearing for guiding on a second lateral extension surface of the guide rail opposite to the first lateral extension surface; and a third guide bearing for guiding on an upper extension surface of the guide rail extending between the first lateral extension surface and the second lateral extension surface.

[0029] It should be understood that the guide carriage preferably includes at least one such first guide bearing, at least one such second guide bearing, and at least one such third guide bearing. For example, the first guide bearing, the second guide bearing, and the third guide bearing may each be provided in two or three different configurations.

[0030] The second lateral extension surface on which the second guide bearing is disposed is preferably configured parallel to the first lateral extension surface of the guide rail, the first lateral extension surface forming the first recessed side of the groove. In this respect, the second guide bearing is preferably positioned opposite the first guide bearing and friction wheel of the guide rail. The second guide bearing is also positioned relative to the guide rail opposite the opposing bearing. Due to the opposing bearing used according to the invention, the lateral mounting of the guide carriage (i.e., by means of the mounting of the first and second guide bearings) has almost no lateral force, which has a great advantage in terms of accuracy, and also eliminates the need for two guide bearings.

[0031] The third guide bearing, arranged on the upper extended surface of the guide rail, is essentially used as a support to absorb the weight of the movable parts of the coordinate measuring machine.

[0032] According to the preferred configuration, the first guide bearing, the second guide bearing, the third guide bearing and / or the opposing bearing have a sliding bearing, preferably an air bearing.

[0033] Therefore, very low frictional mounting is ensured, which is achieved by the arrangement according to the invention, which also has low lateral force.

[0034] According to another configuration, the opposed bearing has two sliding bearings, preferably air bearings, which are arranged offset from each other along the longitudinal axis.

[0035] This provides additional support for the friction wheel actuator, allowing not only force absorption via one or more opposed bearings, but also torque absorption. Therefore, the actuator's drive torque can be almost completely decoupled from the moving part or guide carriage, and only shear force can be transmitted to the moving part or guide carriage.

[0036] According to another configuration, the actuator is connected to the guide carriage via a flexure configured to transmit the driving force generated by the actuator and acting along the longitudinal axis to the guide carriage.

[0037] The advantage of this flexure is that it results in a further minimization of lateral force transmission from the actuator to the guide carriage. The flexure is preferably used only to transmit shear or tension forces, but due to its typically low bending stiffness, it allows for relative movement (rotation) of the guide carriage relative to the actuator. This decouples further shear forces and torques between the actuator and the guide carriage, and therefore between the actuator and the movable or driven components.

[0038] The flexure is preferably configured to transmit a lateral force acting transversely to the longitudinal axis, the magnitude of which is at most one-fifth, preferably at most one-tenth, of the driving force of the actuator acting along the longitudinal axis.

[0039] This typical characteristic of flexural components is advantageously used here to further reduce the lateral force transmission between the drive and the moving parts. This significantly reduces the load on the guide bearing and the drive itself.

[0040] According to a preferred configuration, the flexural element has a metal sheet. The flexural element is particularly preferably configured as a metal sheet.

[0041] The metal sheet is preferably fastened to the guide carriage at one end and connected to the actuator at the other end. Therefore, the flexure is designed to be as simple and cost-effective as possible, while still exhibiting high stability in transmitting tension and shear forces.

[0042] According to another configuration, the driver has a drive motor that is connected to the friction wheel via a transmission device, wherein the drive motor is arranged outside the groove.

[0043] The advantage of this is that waste heat from the drive motor is not directly coupled to the drive and guide structures of the coordinate measuring machine. For example, the drive motor can be positioned externally to be exposed to a free airflow during drive movement, which ensures optimal cooling of the drive motor.

[0044] The transmission device can be a single-stage transmission device or a multi-stage transmission device. The transmission device preferably has a transmission belt, such as a V-belt or a toothed belt.

[0045] According to another configuration, the coordinate measuring machine has a measuring stage, with guide rails integrally formed on the measuring stage, and grooves formed in the measuring stage.

[0046] The integrated design of the guide rails and adjacent grooves ensures optimal stability and maximum strength. The measuring platform is preferably made of granite or other hard rock.

[0047] For arrangements that save as much space as possible, a preferred configuration is provided in which the upper extension surface of the guide rail is arranged in the plane containing the top side of the measuring stage, with a groove formed in the top side.

[0048] The guide rails and grooves (in which the drive is at least partially arranged) are thus arranged to save the most space and are almost hidden in the measuring stage.

[0049] In another configuration, the majority of the actuator is arranged within the groove. In other words, more than 50% of the volume of the friction wheel actuator is preferably arranged within the groove.

[0050] This not only ensures that the drive is housed in the recess in a space-saving manner, but also protects the drive from external influences because the drive is housed in the recess.

[0051] In another configuration, the friction wheel is connected to the opposing bearing via a spring and / or damping element.

[0052] This ensures optimal suspension or damping of the contact pressure between the friction wheel and the opposed bearing.

[0053] According to another configuration, the movable component is part of a support structure for carrying a measuring head used to measure the dimensions of an object.

[0054] Depending on the design of the coordinate measuring machine, the load-bearing structure may have a column, cantilever, bridge, or gantry design. A drive is used, for example, to move the load-bearing structure along the y-axis.

[0055] It goes without saying that the features described above, as well as those to be explained below, can be used not only in their respective circumstances in the specified combinations, but also in other combinations or individually without departing from the scope of the invention. Attached Figure Description

[0056] Several exemplary embodiments of the invention are illustrated in the accompanying drawings, and these embodiments will be described in more detail in the following description. In the accompanying drawings:

[0057] Figure 1 A simplified schematic diagram of a coordinate measuring machine is shown to illustrate the basic structure of a coordinate measuring machine according to an exemplary embodiment;

[0058] Figure 2A perspective view showing details of the drive-related parts of a coordinate measuring machine according to the invention, based on a first exemplary embodiment;

[0059] Figure 3 It shows Figure 2 A cross-sectional view of the drive-related portion of a first exemplary embodiment of a coordinate measuring machine according to the present invention is shown.

[0060] Figure 4 It shows the method of displaying according to Figure 2 and Figure 3 Another view showing details of a portion of the drive of the coordinate measuring machine according to the invention, as illustrated in the first exemplary embodiment; and

[0061] Figure 5 A perspective view is shown illustrating a portion of the drive of a coordinate measuring machine according to the invention, based on a second exemplary embodiment. Detailed Implementation

[0062] Figure 1 A simplified schematic diagram of a coordinate measuring machine is shown, and the basic structure of this machine is explained below based on this diagram. The coordinate measuring machine is generally identified by reference numeral 10 in the accompanying drawing.

[0063] The coordinate measuring machine 10 has a measuring stage 12. The measuring stage 12 itself serves as a receiver for measuring objects or is used to mount such a receiver. In other words, as schematically indicated herein, the measuring object 14 can be directly mounted on the measuring stage 12 or clamped in a receiver mounted on the measuring stage 12.

[0064] The measuring platform 12 is typically a solid slab made of hard rock, which is stable and not easily vibrated. Granite is a particularly preferred material for the measuring platform 12.

[0065] In the exemplary embodiment shown here, the coordinate measuring machine 10 has a gantry design. The coordinate measuring machine has a gantry 16 arranged on the measuring table 12.

[0066] The gantry 16 serves as a movable support structure for the measuring head 18, by means of which the measuring object 14 is measured. The gantry 16 has two vertical columns 20, which are connected to each other via a crossbeam 22. A carriage 24 is movably mounted on the crossbeam 22. The carriage 24 carries a sleeve shaft 26, at the lower end of which the measuring head 18 is located.

[0067] exist Figure 1 In the illustrative example, the measuring head 18 is designed as a tactile measuring head. The measuring head 18 has a measuring tool 28, which is configured here as a tactile stylus, with a probe ball 30, typically made of ruby, arranged at the lower free end of the tactile stylus.

[0068] Depending on the application, the measuring head 18 may also have a rotary joint (not shown here), by means of which the measuring tool 28 or the entire measuring head 18 can be rotated and / or spun around one, two or more axes.

[0069] As an alternative, the measuring head 18 itself can also be configured as an optical measuring head that optically (i.e., non-contactly) measures the object 14.

[0070] The positioning device 32 includes a gantry 16, a carriage 24, and a sleeve shaft 26. In the coordinate measuring machine 10, the positioning device is used to automatically and motor-driven position the measuring head 18 relative to the object being measured 14 or the measuring table 12. The positioning device 32 includes an evaluation and control unit 34 and several drivers. The evaluation and control unit has a calculation unit 36 ​​and a display device 38. Figure 1 The reference numerals 40, 40', and 40'' in the accompanying drawings are for illustrative purposes only.

[0071] In the example shown (where the coordinate measuring machine 10 has a gantry design), the aforementioned actuators 40, 40', and 40'' move the measuring head 18 relative to the fixed measuring stage 12. Here, the measuring head 18 can move along three coordinate axes orthogonally oriented to each other. These coordinate axes are designated as the x-axis, y-axis, and z-axis. Actuator 40 is designed to move the gantry 16 relative to the measuring stage 12 along the y-axis. Actuator 40' is designed to move the carriage 24 along the x-axis on the crossbeam 22. Actuator 40'' is designed to move the sleeve shaft 26 relative to the carriage 24 along the z-axis.

[0072] It should be noted that the invention is explained by way of example only based on a coordinate measuring machine 10 with a gantry design. However, in principle, the invention can also be used in coordinate measuring machines with cantilever, bridge, or column designs. Depending on the construction type of the coordinate measuring machine 10, relative movement of the measuring head 18 and the measuring stage 12 along one, two, or all three spatial directions (x, y, z) can also be implemented through the mobility of the measuring stage 12.

[0073] The evaluation and control unit 34 is preferably used not only to control the individual drives 40, 40', 40'', but also to evaluate the data obtained from the measuring head 18 and determine the spatial coordinates of the object to be measured 14 based on the evaluated measurement data. The evaluation and control unit 34 can be configured, for example, as a PC with a computing unit 36 ​​storing corresponding metrology software used to control the coordinate measuring machine and evaluate the measurement data obtained from it. The display device 38 is preferably a computer monitor, by which the user of the coordinate measuring machine 10 can plan the measurement sequence and then display the measurement results. For simplicity, typical input devices such as keyboards, mice, and joysticks are not shown here.

[0074] Reference numeral 42 denotes several measuring scales, which also belong to the positioning device 32 of the coordinate measuring machine 10. These measuring scales 42 are designed, in conjunction with corresponding reading heads (not shown here), to determine the current position of the gantry 16 relative to the measuring table 12, the position of the carriage 24 relative to the crossbeam 22, and the position of the sleeve shaft 26 relative to the carriage 24, respectively. An encoder is typically arranged in the measuring head 28, by means of which the current rotational and slewing positions of the measuring tool 28 relative to the sleeve shaft 26 can be determined in a similar manner. The aforementioned position values ​​are fed to the evaluation and control unit 34, which then determines the current spatial coordinates of the measuring points on the object to be measured 14 based on the scale values ​​and encoder values.

[0075] The evaluation and control unit 34 is further designed to actuate the drivers 40, 40', 40'' accordingly during measurement to move the measuring head 18 or measuring tool 28 relative to the object being measured 14 to the corresponding desired measurement position.

[0076] The structure of the drive 40 is described below, which is used to drive the gantry 16 along the y-axis relative to the measuring stage 12. As mentioned above, since the coordinate measuring machine 10 does not necessarily have to have a gantry design, the gantry 16 can also generally be referred to as the movable part 16, which is moved by means of the drive 40 for dimensional measurement of the object 14.

[0077] In this exemplary embodiment, the movable component 16, configured as a gantry, is guided longitudinally along the y-axis on the guide rail 46 by means of a guide carriage 44. In other words, the y-axis forms the longitudinal axis of the guide rail 46. The guiding details and structural details of the actuator 40 are described in... Figure 2 and Figure 3 It is particularly clear in the text.

[0078] like Figure 2 and Figure 3As shown, the guide rail 46, which is longitudinally movably mounted on the guide carriage 44 along the y-axis, has a rectangular cross-section. The guide rail 46 has two opposing lateral extending surfaces 48 and 50, referred to in this case as the "first lateral extending surface 48" and the "second lateral extending surface 50". The two extending surfaces 48 and 50 of the guide rail 46 preferably extend parallel to each other. On the top side, the guide rail 46 has an upper extending surface 52, which is oriented transversely to, and preferably orthogonally to, the two lateral extending surfaces 48 and 50, and extends between the two extending surfaces 48 and 50.

[0079] A groove 54 extending parallel to the guide rail 46 is formed in the measuring stage 12, the groove being adjacent to or directly adjacent to the guide rail 46. In other words, the groove 54 extends along the longitudinal axis y of the guide rail 46. In this exemplary embodiment, the groove 54 also has a rectangular cross-section. The groove has two opposing groove sides 56, 58, which extend parallel to each other and are referred to in this case as "first groove side 56" and "second groove side 58". The groove base of the groove 54, which extends laterally and preferably orthogonally, is identified by reference numeral 60, and forms the bottom or base of the groove 54 and extends between the two groove sides 56, 58.

[0080] The arrangement of the groove 54 directly adjacent to or adjacent to the guide rail 46, as mentioned above, specifically means that the first lateral extension surface 48 of the guide rail 46 simultaneously forms the first groove side surface 56 of the groove 54. In other words, the first lateral extension surface 48 of the guide rail 46 and the first groove side surface 56 of the groove 54 are the same surface.

[0081] According to the present invention, the groove 54 is used not only to receive a portion of the guide carriage 44, but also to receive a portion of the drive 40, as will be explained in detail below.

[0082] The driver 40 is configured as a friction wheel driver. The friction wheel driver has a motor-driven friction wheel 62 that frictionally contacts a first groove side 56 of the groove 54 or a first lateral extension surface 48 of the guide rail 46, and rolls along the longitudinal axis y on the first groove side or the first lateral extension surface. The friction wheel 62 is driven by a drive motor 64, which is preferably configured as an electric motor.

[0083] In the exemplary embodiment shown, the drive motor 64 is coupled to the friction wheel 62 via a single-stage transmission 66 having a pulley 68 and a rotating drive belt 70 disposed on the pulley. According to this exemplary embodiment, the drive motor 64 itself is disposed outside the recess 54. This arrangement has the particular advantage of optimal cooling of the drive motor 64 and prevents heat from being introduced into the guide structure of the positioning device 32 through the drive motor 64.

[0084] The guide carriage 44 is supported on the guide rail 46 by means of several guide bearings 72, 74, and 76. These guide bearings 72, 74, and 76 are preferably designed as sliding bearings, and particularly preferably as air bearings. A first guide bearing 72 is used to mount and guide the guide carriage 44 on a first lateral extension surface 48 of the guide rail 46. A second guide bearing 74 is used to guide on a second lateral extension surface 50 of the guide rail 46. A third guide bearing 76 is used to guide on an upper extension surface 52 of the guide rail 46. Although in Figure 2 Only three such guide bearings 72, 74, and 76 can be seen in the image, but it should be understood that the other three of these guide bearings are preferably arranged in the y-direction on the opposite side of the guide carriage.

[0085] The actuator 40 further includes a counter-bearing 78, which is preferably designed as a sliding bearing, and particularly preferably as an air bearing. This counter-bearing 78 supports the friction wheel 62. Specifically, the counter-bearing 78 is used to reduce or even completely eliminate the effect of the contact pressure of the friction wheel 62 on the guide bearings 72, 74. For this purpose, the counter-bearing 78 is supported on the second recess side 58 of the recess 54, i.e., on the opposite side of the recess against which the friction wheel 62 rests.

[0086] Without the opposed bearing 78, the contact pressure of the friction wheel 62 pressing against the side 56 of the first groove would have to be absorbed by the second guide bearing 74. The runout error causing dynamic changes in the contact pressure of the friction wheel 62 would therefore have a direct impact on the supporting forces acting on the guide bearings 72 and 74, leading to dynamic changes in the corresponding air gap, especially in the case of air bearings. The opposed bearing can minimize or even completely eliminate the effects of these undesirable lateral forces.

[0087] In the exemplary embodiment shown, the contact pressure of the friction wheel 62 is generated by means of a spring element 80 arranged between the friction wheel 62 and the opposing bearing 78. In other words, the friction wheel 62 is connected to the opposing bearing 78 via the spring element 80. Instead of... Figure 3 The indicated mechanical spring element 80 can also be a pneumatic cylinder. For example, the friction wheel 62 can be connected to the opposing bearing 62 via a pneumatic cylinder.

[0088] To further minimize the aforementioned undesirable effects of the lateral forces transmitted from the friction wheel 62 to the guide bearings 72, 74, in this exemplary embodiment, the drive 40 is connected to the guide carriage 44 via a flexure 82. This flexure 82 is particularly suitable for… Figure 4As seen in the image, the flexure has a metal sheet connected at one end to the guide carriage 44 and at the other end to the actuator 40. In this exemplary embodiment, the side of the flexure 82 connected to the actuator 40 is coupled to the spring element 80 via a metal plate 84.

[0089] The flexure 82 is configured to transmit the driving force generated by the actuator 40 and acting along the longitudinal axis y to the guide carriage 44. Simultaneously, the flexure 82 is designed to minimize the transmission of lateral forces that act transversely to the longitudinal axis y, i.e., in the x-direction. The force transmission of the flexure 82 in the x-direction (i.e., orthogonal to the y-axis) is preferably at most one-fifth, preferably at most one-tenth, of the force transmitted along the longitudinal axis y. This characteristic is inherent to this flexure 82.

[0090] In addition to minimizing the lateral forces transmitted to the guide bearings 72, 74, the current arrangement of the actuator 40 has the following advantages: most of the actuator 40 is arranged in a space-saving and protected manner within the recess 54. Furthermore, compared to previous solutions, the actuator 40 is positioned closer to the center of gravity of the gantry 16, which is mechanically advantageous. Moreover, from a safety perspective, the actuator 40 is length-independent and less critical than, for example, a rotating belt. Additionally, the recess 54 and the portion of the actuator 40 contained therein can optionally be covered in a simple manner.

[0091] at last, Figure 5 A second exemplary embodiment is shown, which is related to... Figure 4 The difference in the exemplary embodiment shown is that a pair of opposed bearings 78, 78' are used instead of a single opposed bearing 78. The second opposed bearing 78' is arranged to be offset relative to the first opposed bearing 78 along the longitudinal axis y. This configuration is particularly advantageous because the torque generated during the acceleration of the drive 40 can be optimally absorbed by the two opposed bearings 78, 78' in this way.

[0092] exist Figure 5 In the second exemplary embodiment shown, the driver 40 is also preferably coupled to the guide carriage 44 by means of a flexure 82'.

Claims

1. A coordinate measuring machine (10), comprising: - Component (16), which is movable for measuring the dimensions of the object (14), and is movably mounted on the guide rail (46) along the longitudinal axis (y). - A driver (40) designed to drive the movable part (16) along the longitudinal axis (y). The actuator (40) is at least partially arranged in a groove (54) that extends parallel to the longitudinal axis (y) and is adjacent to the guide rail (46) in such a way that a first lateral extension surface (48) of the guide rail (46) forms a first groove side surface (56) of the groove (54). The driver (40) has a motor-driven friction wheel (62) that frictionally contacts the side surface of the first groove (56) and rolls along the longitudinal axis (y) on the side surface of the first groove. The actuator (40) further includes a counter bearing (78) for supporting the friction wheel (62) and is supported on a second groove side (58) of the groove (54) opposite to the first groove side (56).

2. The coordinate measuring machine of claim 1, wherein, The first groove side and the second groove side (56, 58) are oriented parallel to each other.

3. Coordinate measuring machine according to claim 1 or 2, wherein The movable component (16) has a guide carriage (44) which is movably mounted on the guide rail (46) along the longitudinal axis (y) and is at least partially arranged in the groove (54).

4. The coordinate measuring machine of claim 3, wherein, The guide carriage (44) has: a first guide bearing (72) for guiding on a first lateral extension surface (48) of the guide rail (46); a second guide bearing (74) for guiding on a second lateral extension surface (50) of the guide rail (46) opposite to the first lateral extension surface (48); and a third guide bearing (76) for guiding on an upper extension surface (52) of the guide rail (46) extending between the first lateral extension surface and the second lateral extension surfaces (48, 50).

5. The coordinate measuring machine of claim 4, wherein, The first guide bearing (72), the second guide bearing (74), the third guide bearing (76) and / or the opposing bearing (78) have sliding bearings, preferably air bearings.

6. The coordinate measuring machine of any one of claims 1 to 4, wherein, The opposed bearing (78) has two sliding bearings, preferably air bearings, arranged offset from each other along the longitudinal axis (y).

7. The coordinate measuring machine of any of claims 3 to 5, wherein, The actuator (40) is connected to the guide carriage (44) via a flexure (82) configured to transmit the driving force generated by the actuator (40) and acting along the longitudinal axis (y) to the guide carriage (44).

8. The coordinate measuring machine of claim 7, wherein, The flexure (82) is configured to transmit a lateral force acting transversely to the longitudinal axis (y), the magnitude of which is at most one-fifth, preferably at most one-tenth, of the driving force acting along the longitudinal axis (y).

9. Coordinate measuring machine according to claim 7 or 8, wherein The flexural element (82) has a metal sheet.

10. Coordinate measuring machine according to any of the preceding claims, wherein, The driver (40) has a drive motor (64) connected to the friction wheel (62) via a transmission device (66), wherein the drive motor (64) is arranged outside the groove (54).

11. The coordinate measuring machine according to any one of the preceding claims, the coordinate measuring machine having a measuring table (12), the guide rail (46) integrally formed on the measuring table, and the groove (54) formed in the measuring table.

12. The coordinate measuring machine according to any one of the preceding claims, wherein, Most of the drive (40) is arranged within the groove (54).

13. The coordinate measuring machine according to any one of the preceding claims, wherein, The friction wheel (62) is connected to the opposing bearing (78) via a spring and / or damping element (80).

14. The coordinate measuring machine according to any one of the preceding claims, wherein, The movable part (16) is part of a support structure for carrying a measuring head (18) for measuring the dimensions of the object (14).

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