JP2018165687A - Three-dimensional coordination measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional coordinate measuring device capable of suppressing a change in a roller diameter caused by a detent groove while eliminating a coaxiality error between a shaft member and a roller portion. SOLUTION: The roller 34 has a roller 34 that is pressed against a side surface of a platen, and includes a drive unit that moves a Y carriage along the side surface of the platen by rotating the roller 34. It has a metal shaft member 36 and a resin-made tubular roller portion 38 outerly mounted on the outer peripheral surface 36A of the shaft member 36, and the outer peripheral surface 36A of the shaft member 36 is provided along the rotation direction of the roller 34. When unfolded, a plurality of detent grooves 40A and 40B inclined with respect to the rotation direction of the roller 34 are formed on the outer peripheral surface 36A of the shaft member 36. [Selection diagram] Fig. 3

Description

  The present invention relates to a three-dimensional coordinate measuring apparatus, and more particularly to a three-dimensional coordinate measuring apparatus that measures the shape of a measurement object by moving a carriage along a side surface of a surface plate.

  In the three-dimensional coordinate measuring apparatus disclosed in Patent Document 1 and the like, a Y carriage is disposed on the upper surface of the surface plate so as to be movable in the front-rear direction (Y-axis direction). The Y carriage has an X guide that is stretched along the left-right direction (X-axis direction), and the X carriage is supported by the X guide so as to be movable in the X-axis direction. The X carriage supports the Z carriage so as to be movable in the vertical direction (Z-axis direction), and a measurement probe is attached to the lower end of the Z carriage.

  The three-dimensional coordinate measuring apparatus disclosed in Patent Document 1 includes a drive unit that moves the Y carriage in the Y-axis direction along the side surface of the surface plate. The drive unit includes a roller that is in contact with the side surface of the surface plate and a motor that rotates the roller, and the friction force between the roller and the side surface of the surface plate is rotated by the motor. Is used to move the Y carriage in the Y-axis direction.

Japanese Patent Laid-Open No. 2006-145823

  A roller that moves the Y carriage as in Patent Document 1 is generally composed of a metal shaft member that is a core metal, and a cylindrical roller portion that is externally mounted on the outer peripheral surface of the shaft member. is there. The roller part is often made of a resin such as urethane or polyurethane, and the roller part is used by being elastically deformed by being pressed against the side surface of the surface plate. Thereby, since a favorable frictional force can be obtained between the roller portion and the side surface of the surface plate, the Y carriage can be moved in the Y-axis direction.

  By the way, there are the following first and second conventional examples of a roller using a resin roller portion.

  The first conventional example is a roller in which a metal shaft member and a resin roller portion are integrated. This roller is obtained by baking and joining a roller portion to a shaft member, and the shaft member and the roller portion are completely integrated.

  The second conventional example is a roller in which the shaft member and the roller portion are not joined, and the roller portion is externally provided on the outer peripheral surface of the shaft member. In this roller, a plurality of anti-rotation grooves are formed on the outer peripheral surface of the shaft member in order to prevent the roller portion from spinning around the shaft member. The direction in which the rotation preventing groove is formed will be described. Generally, when the outer peripheral surface of the shaft member is developed along the rotation direction of the roller, it is generally formed in a direction orthogonal to the rotation direction of the roller. By forming the anti-rotation groove in this direction, the anti-rotation action can be effectively exhibited.

  However, the first and second conventional examples described above have the following problems.

  In the first conventional example, since the shaft member and the roller portion are joined, the coaxiality error between the shaft member and the roller portion cannot be escaped. For this reason, the reaction force that the roller receives from the side surface of the surface plate (reaction force in the direction perpendicular to the side surface) is generated as a large swell for each rotation of the roller, and this swell is transmitted to the Y carriage. As a result, when the first conventional example is used, there is a problem that an error component in a direction perpendicular to the side surface of the surface plate is generated.

  In the second conventional example, since the shaft member and the roller portion are not joined, the coaxiality error between the shaft member and the roller portion can be released by the roller portion floating with respect to the shaft member. However, when the rotation-preventing groove (groove in the direction orthogonal to the rotation direction of the roller) formed on the outer peripheral surface of the shaft member is pressed against the side surface of the surface plate via the roller portion, a part of the roller portion is Since it enters into the anti-rotation groove, the diameter of the roller periodically changes at the position of the plural anti-rotation grooves. When the diameter of the roller changes in this way, the reaction force received by the roller from the side surface of the surface plate periodically varies. As a result, even when the second conventional example is used, there is a problem that an error component in a direction perpendicular to the side surface of the surface plate is generated.

  As described above, conventionally, there has not been a three-dimensional coordinate measuring apparatus that can suppress a change in the diameter of the roller due to the non-rotating groove while eliminating the coaxiality error between the shaft member and the roller portion.

  The present invention has been made in view of such circumstances, and is capable of suppressing a change in the diameter of the roller due to the non-rotating groove while eliminating the coaxiality error between the shaft member and the roller portion. It aims at providing a measuring device.

  A three-dimensional coordinate measuring apparatus for achieving the object of the present invention has a top surface and a side surface, and supports a surface plate on which the measurement object is placed and a measurement probe that comes into contact with the measurement object. A carriage that is movable along the side surface of the surface plate, a roller that presses and contacts the side surface of the surface plate, and a drive unit that moves the carriage along the side surface of the surface plate by rotating the roller; The roller of the drive unit includes a metal shaft member and a resin-made cylindrical roller portion that is externally mounted on the outer peripheral surface of the shaft member, and the outer peripheral surface of the shaft member is arranged in the rotation direction of the roller. When deployed along, the outer circumferential surface of the shaft member is formed with a rotation-preventing groove that is inclined with respect to the rotation direction of the roller.

  According to the present invention, since the roller is configured by mounting the roller portion on the shaft member, the coaxiality error between the shaft member and the roller portion can be eliminated, and the rotation stopper formed on the outer peripheral surface of the shaft member Since the groove is formed to be inclined with respect to the rotation direction of the roller, a change in the diameter of the roller due to the rotation preventing groove can be suppressed.

  In one embodiment of the present invention, it is preferable that a plurality of the non-rotating grooves are formed at equal intervals along the rotation direction of the roller.

  According to an aspect of the present invention, it is possible to further suppress a change in the diameter of the roller due to the rotation preventing groove.

  In one embodiment of the present invention, the plurality of non-rotating grooves have a first groove group and a second groove group, and the first groove group and the second groove group are the same with respect to the rotation direction of the roller. It is preferable to incline in opposite directions at an angle of.

  According to one aspect of the present invention, it is possible to effectively suppress idle rotation of the roller portion while suppressing a change in the diameter of the roller due to the rotation preventing groove.

  ADVANTAGE OF THE INVENTION According to this invention, the change of the diameter of the roller resulting from the groove | channel for rotation prevention can be suppressed, eliminating the coaxiality error of a shaft member and a roller part.

The perspective view which showed the external appearance of the three-dimensional coordinate measuring apparatus with which this invention is applied Front view of the three-dimensional coordinate measuring apparatus shown in FIG. Assembly drawing of roller in drive unit A developed view of the outer peripheral surface of the shaft member developed along the rotation direction of the roller Development view of a shaft member having only eight anti-rotation grooves in the first groove group Development view of a shaft member having only eight anti-rotation grooves in the second groove group Graph comparing the amount of change in roller diameter with roller rotation angle

  Hereinafter, a three-dimensional coordinate measuring apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an appearance of the three-dimensional coordinate measuring apparatus 10 according to the embodiment, and FIG. 2 is a front view of the three-dimensional coordinate measuring apparatus 10.

  The three-dimensional coordinate measuring apparatus 10 has a surface plate 14 installed on the installation surface via a gantry 12. The surface plate 14 is formed in a rectangular parallelepiped shape by a stone material such as granite or marble, and has a flat upper surface 14A on which a measurement object is placed. 14 A of upper surfaces are arrange | positioned in parallel with respect to the X-axis and Y-axis orthogonal to a horizontal direction, and are arrange | positioned in the orthogonal direction with respect to the Z-axis of a perpendicular direction.

  A gate-shaped Y carriage (carriage) 16 is installed on the upper surface 14 </ b> A side of the surface plate 14 so as to straddle the surface plate 14. The Y carriage 16 includes a right Y carriage 18 and a left Y carriage 20 that are erected along the Z-axis direction. Further, the Y carriage 16 has a beam-shaped X guide 22 spanned along the X-axis direction on the upper ends of the right Y carriage 18 and the left Y carriage 20.

  As shown in FIG. 2, the lower end of the right Y carriage 18 is supported on the side surface 14B of the surface plate 14 so as to be movable in the Y-axis direction, and the lower end of the left Y carriage 20 is slid onto the upper surface 14A of the surface plate 14. It is supported freely. A driving unit 24 is provided at the lower end of the right Y carriage 18, and the Y carriage 16 is moved in the Y-axis direction by the driving force of the driving unit 24. The drive unit 24 will be described later.

  A Z column 26 is supported by the X guide 22 so as to be movable along the X guide 22 in the X-axis direction. The Z column 26 has a built-in drive unit that comes into contact with the X guide 22 and is moved in the X-axis direction along the X guide 22 by the driving force of the drive unit.

  Further, a columnar Z carriage 28 extending along the Z axis is supported inside the Z column 26 so as to be movable in the Z axis direction, and the lower end side of the Z carriage 28 is the lower end side of the Z column 26. Protruding from. The Z column 26 has a built-in drive unit that contacts the Z carriage 28, and the Z carriage 28 is moved in the Z-axis direction by the drive force of the drive unit.

  A measurement probe 30 such as a touch probe is attached to the lower end portion of the Z carriage 28. The measurement probe 30 has, for example, a rod-like stylus 32 having a tip sphere. The measurement probe 30 detects the presence or absence of contact of the tip sphere of the stylus 32 with the measurement target and the amount of displacement of the stylus 32 caused by the contact of the tip sphere 32 with the measurement target.

  According to the three-dimensional coordinate measuring apparatus 10 configured as described above, the Y carriage 16 moves in the Y axis direction, the Z column 26 moves in the X axis direction, and the Z carriage 28 moves in the Z axis direction. The stylus 32 of the measurement probe 30 is moved in the X, Y, and Z axis directions, and the tip sphere of the stylus 32 is moved along the surface of the measurement object placed on the upper surface 14A of the surface plate 14. At that time, the position (movement amount) of the Y carriage 16 in the Y axis direction, the position (movement amount) of the Z column 26 in the X axis direction, the position (movement amount) of the Z carriage 28 in the Z axis direction, and the stylus 32. By measuring the position (displacement amount), the three-dimensional coordinates of each position on the surface of the measurement object are measured. Since the processing related to the measurement of the three-dimensional coordinates is well known, detailed description thereof is omitted.

  Next, the drive unit 24 that moves the Y carriage 16 in the Y-axis direction will be described.

  As shown in FIG. 2, the drive unit 24 includes a roller 34 that is pressed against the side surface 14 </ b> B of the surface plate 14. The drive unit 24 includes a motor 35 that rotates the roller 34. The motor 35 drives the roller 34 in the forward rotation direction and the reverse rotation direction, thereby moving the Y carriage 16 along the side surface 14 </ b> B of the surface plate 14. It can be reciprocated in the Y-axis direction.

  The right Y carriage 18 of the Y carriage 16 is slidably supported on the surface plate 14 via a plurality of air pads. Specifically, the right Y carriage 18 is slidably supported on the upper surface 14 </ b> A of the surface plate 14 via the air pad 42, and is slidably supported on the lower surface 14 </ b> C of the surface plate 14 via the air pad 44. Although not shown in FIG. 2, the right Y carriage 18 is slidably supported on the side surface 14B of the surface plate 14 via a pair of air pads arranged in the Y-axis direction with the roller 34 interposed therebetween. Similarly, the left Y carriage 20 is also slidably supported on the upper surface 14A of the surface plate 14 via the air pad 46. The right Y carriage 18 is slidably supported on the surface plate 14 via the air pads 42, 44, 46, so that the Y carriage 16 can move in the Y-axis direction with respect to the surface plate 14. Become.

  FIG. 3 is an assembly view of the roller 34 of the drive unit 24.

  The roller 34 includes a metal shaft member 36 and a resin-made cylindrical roller portion 38 that is sheathed on the outer peripheral surface 36 </ b> A of the shaft member 36.

  FIG. 4 is a development view in which the outer peripheral surface 36 </ b> A of the shaft member 36 is developed along the rotation direction A of the roller 34. As shown in FIG. 4, on the outer peripheral surface 36A of the shaft member 36, a first groove group comprising eight anti-rotation grooves 40A inclined with respect to the rotation direction A of the roller 34 and eight anti-rotation grooves are also formed. A second groove group consisting of 40B and 16 anti-rotation grooves 40A, 40B consisting of 40B are formed.

  The eight anti-rotation grooves 40A of the first groove group are formed at an equal pitch P along the rotation direction A of the roller 34. Further, the width W in which one rotation-preventing groove 40A is formed in the circumferential direction of the roller 34 is also formed to be equal, and further, the pitch P and the width W are formed to be equal.

  Similarly, the eight anti-rotation grooves 40 </ b> B of the second groove group are also formed at an equal pitch P along the rotation direction A of the roller 34. Further, the width W in which one rotation-preventing groove 40B is formed in the circumferential direction of the roller 34 is also formed to be equal, and further, the pitch P and the width W are formed to be equal. Further, the eight anti-rotation grooves 40A of the first groove group and the eight anti-rotation grooves 40B of the second groove group are opposite to each other at the same angle α with respect to the rotation direction A of the roller 34. It is formed to be inclined. Therefore, various types of anti-rotation grooves 40A and 40B can be formed by appropriately changing the pitch P, width W, and angle α of the anti-rotation grooves 40A and 40B.

  The eight anti-rotation grooves 40A in the first groove group in FIG. 3 have ends a and b in a direction B orthogonal to the rotation direction A of the roller 34. The end a of the anti-rotation groove 40A is formed at a position overlapping the end b of the adjacent anti-rotation groove 40A in the direction B, and the end b of the anti-rotation groove 40A is adjacent to the anti-rotation groove 40A. It is formed at a position overlapping with the end a of 40A in the direction B.

  The same applies to the eight anti-rotation grooves 40B of the second groove group, but the eight anti-rotation grooves 40B have ends c and d in the direction B perpendicular to the rotation direction of the roller 34. The end c of the anti-rotation groove 40b is formed at a position overlapping with the end d of the adjacent anti-rotation groove 40B in the direction B, and the end d of the anti-rotation groove 40B is adjacent to the anti-rotation groove 40B. It is formed at a position overlapping with the end c of 40B in the direction B.

  According to the drive unit 24 configured as described above, the roller 34 is configured by mounting the roller part 38 on the shaft member 36 as shown in FIG. 3, so that the coaxiality error between the shaft member 36 and the roller part 38 is eliminated. be able to. Further, as shown in FIG. 4, a plurality of (16 in the embodiment) anti-rotation grooves 40 </ b> A and 40 </ b> B formed on the outer peripheral surface 36 </ b> A of the shaft member 36 are inclined with respect to the rotation direction A of the roller 34. Therefore, a change in the diameter of the roller 34 due to the formation of the rotation preventing grooves 40A and 40B on the outer peripheral surface 36A can be suppressed.

  In other words, since the conventional anti-rotation groove is formed in a direction perpendicular to the rotation direction of the roller, when the anti-rotation groove is pressed against the side surface of the surface plate via the roller portion, the anti-rotation groove rotates. The amount of the roller part that enters the stopper groove increases. As a result, the amount of change in the diameter of the roller increases, which affects the measurement accuracy of the three-dimensional coordinate measuring apparatus.

  On the other hand, in the roller 34 of the embodiment, the rotation preventing grooves 40A and 40B formed on the outer peripheral surface 36A of the shaft member 36 are formed to be inclined with respect to the rotation direction A of the roller 34. When the anti-rotation grooves 40A and 40B are pressed against the side surface 14B of the surface plate 14 through the roller portion 38, the amount of the roller portion 38 that enters the anti-rotation grooves 40A and 40B decreases. As a result, a change in the diameter of the roller 34 caused by the anti-rotation grooves 40A and 40B can be suppressed, and the measurement accuracy of the three-dimensional coordinate measuring apparatus can be improved.

  Further, since the anti-rotation grooves 40A and 40B are formed at equal intervals (pitch P) along the rotation direction A of the roller 34, the change in the diameter of the roller 34 caused by the anti-rotation grooves 40A and 40B is further increased. Can be suppressed. The anti-rotation grooves 40A and 40B are not necessarily formed at equal intervals, but the change in the diameter of the roller 34 caused by the anti-rotation grooves 40A and 40B and the idle rotation of the roller portion 38 with respect to the shaft member 36 are taken into consideration. In this case, it is preferably formed at regular intervals. Further, the number of the anti-rotation grooves 40A and 40B is not limited to eight. For example, one anti-rotation groove may be spirally formed on the outer peripheral surface 36A of the shaft member 36. . Even this one spiral anti-rotation groove is included in the anti-rotation groove inclined with respect to the rotation direction of the roller.

  Furthermore, the anti-rotation groove of the embodiment includes a first groove group including eight anti-rotation grooves 40A and a second groove group including eight anti-rotation grooves 40B. The first groove group and the second groove group are inclined in opposite directions at the same angle α with respect to the rotation direction A of the roller 34.

  By forming such anti-rotation grooves 40A and 40B, it is possible to effectively suppress idle rotation of the roller portion 38 while suppressing changes in the diameter of the roller 34 caused by the anti-rotation grooves 40A and 40B. .

  Hereinafter, modifications of the anti-rotation groove formed on the outer peripheral surface 36A of the shaft member 36 will be described.

  3 and 4, the first groove group and the second groove group are provided as the form of the rotation preventing groove, but as shown in the developed view of FIG. The 2nd form which has only groove 40A may be sufficient. Similarly, as shown in the developed view of FIG. 6, a third configuration having only eight anti-rotation grooves 40 </ b> B in the second groove group may be used.

  Here, the amount of change in the diameter of the roller with respect to the rotation angle of the roller will be compared using the graph shown in FIG. In FIG. 7, the amount of change in the diameter of the roller is indicated on the vertical axis, and the rotation angle of the roller is indicated on the horizontal axis. The solid line C in the graph indicates the amount of change in the diameter of the roller in the second and third forms shown in FIGS. 5 and 6, and the broken line D in the graph indicates the amount of change in the diameter of the conventional roller. Yes. As an example of a conventional roller, an example in which eight anti-rotation grooves are formed at equal intervals along a direction orthogonal to the rotation direction of the roller is illustrated.

  The amount of change in the diameter of the roller in the second form shown in FIG. 5 is that the end a of the anti-rotation groove 40A and the end b of the anti-rotation groove 40A adjacent to the anti-rotation groove 40A are: A minute amount of change e occurs at intervals of 45 degrees that overlap in direction B. The same applies to the roller of the third form in FIG.

  On the other hand, in the conventional roller, since the rotation-preventing groove is formed in a direction orthogonal to the rotation direction of the roller, a large change amount f is generated at intervals of 45 degrees.

  Therefore, as can be seen from the graph of FIG. 7, by providing the shaft member 36 with the inclined anti-rotation groove 40A or anti-rotation groove 40B, the change in the diameter of the roller 34 is greatly suppressed compared to the conventional roller. Can do.

  On the other hand, as a modification of the second embodiment shown in FIG. 5, the pitch P and the width W of the anti-rotation groove 40A are changed, and the end a of the anti-rotation groove 40A is adjacent to the anti-rotation groove 40A. The anti-rotation groove 40A may be formed so that the end b of the anti-rotation groove 40A does not overlap in the direction B. Similarly, as a modification of the third embodiment shown in FIG. 6, the pitch P and the width W of the anti-rotation groove 40B are changed, and the end c of the anti-rotation groove 40B is adjacent to the anti-rotation groove 40B. The anti-rotation groove 40B may be formed so that the end d of the anti-rotation groove 40B does not overlap in the direction B.

  According to the modification of the second embodiment and the modification of the third embodiment, the amount of change in the diameter of the roller can be made smaller than the amount of change e in FIG. In these modified examples, there are portions where the anti-rotation grooves 40A and 40B do not exist in the circumferential direction of the outer peripheral surface 36A of the shaft member 36, and the effect on idling may be reduced, so idling is reliably prevented. From this point of view, the second form in FIG. 5 and the third form in FIG. 6 are preferable to these modifications.

  DESCRIPTION OF SYMBOLS 10 ... Three-dimensional coordinate measuring device, 12 ... Stand, 14 ... Surface plate, 16 ... Y carriage, 18 ... Right Y carriage, 20 ... Left Y carriage, 22 ... X guide, 24 ... Drive part, 26 ... Z column, 28 ... Z carriage, 30 ... measurement probe, 32 ... stylus, 34 ... roller, 35 ... motor, 36 ... shaft member, 36A ... outer peripheral surface, 38 ... roller part, 40A ... rotation prevention groove, 40B ... rotation prevention groove, 42 ... Airpad, 44 ... Airpad, 46 ... Airpad

Claims (3)

A surface plate having an upper surface and side surfaces, on which the measurement object is placed;
A carriage that supports the measurement probe in contact with the measurement object and is movable along the side surface of the surface plate;
A driving unit that has a roller that is pressed against and contacted with the side surface of the surface plate, and moves the carriage along the side surface of the surface plate by rotating the roller;
With
The roller of the drive unit includes a metal shaft member, and a resin-made cylindrical roller unit that is externally provided on the outer peripheral surface of the shaft member.
When the outer peripheral surface of the shaft member is developed along the rotation direction of the roller, a three-dimensional rotation prevention groove that is inclined with respect to the rotation direction of the roller is formed on the outer peripheral surface of the shaft member. Coordinate measuring device.   The three-dimensional coordinate measuring apparatus according to claim 1, wherein a plurality of the non-rotating grooves are formed at equal intervals along a rotation direction of the roller.   The anti-rotation groove has a first groove group and a second groove group, and the first groove group and the second groove group are opposite to each other at the same angle with respect to the rotation direction of the roller. The three-dimensional coordinate measuring apparatus according to claim 1 or 2, wherein

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