JP7358723B2 - drive device - Google Patents

Description

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

In the three-dimensional coordinate measuring device disclosed in Patent Document 1 and the like, a Y carriage is disposed above a surface plate so as to be movable in the front-rear direction (Y-axis direction). The Y carriage has an X guide extending 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. Further, a Z carriage is supported by the X 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 device 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. This drive unit has a roller that comes into contact with the side surface of the surface plate, and a motor that rotates this roller. By rotating the roller with the motor, frictional force between the roller and the side surface of the surface plate is generated. is used to move the Y carriage in the Y-axis direction.

Japanese Patent Application Publication No. 2016-145823

The 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 wrapped around the outer peripheral surface of the shaft member. be. Further, the roller portion is often made of resin such as urethane or polyurethane, and is used after being elastically deformed by being pressed against the side surface of the surface plate. As a result, a good frictional force can be obtained between the roller portion and the side surface of the surface plate, so that the Y carriage can be moved in the Y-axis direction.

By the way, there are the following first and second conventional examples of roller forms that use resin roller parts.

A first conventional example is a roller in which a metal shaft member and a resin roller part are integrated. This roller has a roller portion bonded to a shaft member by baking, and the shaft member and roller portion are completely integrated.

A second conventional example is a roller in which the shaft member and the roller portion are not joined, and the roller portion is sheathed 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 rotating idly with respect to the shaft member. To explain the direction in which the anti-rotation groove is formed, it is generally formed in a direction perpendicular to the rotational direction of the roller when the outer circumferential surface of the shaft member is developed along the rotational direction of the roller. By forming the anti-rotation groove in this direction, the anti-rotation effect can be effectively exerted.

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, it is impossible to eliminate coaxiality errors between the shaft member and the roller portion. For this reason, the reaction force (reaction force in the direction perpendicular to the side surface) that the roller receives from the side surface of the surface plate is generated as a large undulation every time the roller goes around, and this undulation is transmitted to the Y carriage. As a result, when the first conventional example was used, there was a problem in that an error component occurred in a direction perpendicular to the side surface of the surface plate.

In the second conventional example, since the shaft member and the roller portion are not joined, coaxiality errors between the shaft member and the roller portion can be alleviated by floating the roller portion with respect to the shaft member. However, when the anti-rotation groove (groove in the direction perpendicular to the rotational direction of the roller) formed on the outer peripheral surface of the shaft member is pressed against the side surface of the surface plate through the roller part, a part of the roller part Since the roller enters the anti-rotation grooves, the diameter of the roller changes periodically at the positions of the plurality of anti-rotation grooves. When the diameter of the roller changes in this way, the reaction force that the roller receives from the side surface of the surface plate changes periodically. As a result, even when the second conventional example is used, there is a problem in that an error component occurs in a direction perpendicular to the side surface of the surface plate.

As described above, conventionally, there has been no three-dimensional coordinate measuring device that can eliminate the coaxiality error between the shaft member and the roller portion while suppressing the change in the diameter of the roller caused by the anti-rotation groove.

The present invention has been made in view of the above circumstances, and is a three-dimensional coordinate system that can eliminate the coaxiality error between the shaft member and the roller part and suppress the change in the diameter of the roller caused by the anti-rotation groove. The purpose is to provide a measuring device.

A three-dimensional coordinate measuring device for achieving the object of the present invention has an upper surface and a side surface, and supports a surface plate on which an object to be measured is placed and a measurement probe that comes into contact with the object to be measured. , a drive unit that has a carriage that is movable along the side surface of the surface plate, and a roller that presses against the side surface of the surface plate, and that moves the carriage along the side surface of the surface plate by rotating the roller; The roller of the drive unit has a metal shaft member and a resin-made cylindrical roller portion sheathed on the outer circumferential surface of the shaft member, and the roller of the drive section has a metal shaft member and a resin-made cylindrical roller portion that is sheathed on the outer circumferential surface of the shaft member. When the shaft member is unfolded along the shaft member, a detent groove is formed on the outer circumferential surface of the shaft member, which is inclined with respect to the rotational direction of the roller.

According to the present invention, since the roller is constructed by mounting the roller part on the shaft member, it is possible to eliminate the coaxiality error between the shaft member and the roller part, and the rotation stopper formed on the outer peripheral surface of the shaft member Since the rotation groove is formed to be inclined with respect to the rotation direction of the roller, it is possible to suppress a change in the diameter of the roller caused by the rotation prevention groove.

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

According to one embodiment of the present invention, it is possible to further suppress a change in the diameter of the roller due to the anti-rotation groove.

In one form of the present invention, the plurality of anti-rotation grooves have a first groove group and a second groove group, and the first groove group and the second groove group are the same in the rotational direction of the roller. Preferably, they are inclined in opposite directions at an angle of .

According to one embodiment 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 anti-rotation groove.

According to the present invention, it is possible to eliminate a coaxiality error between the shaft member and the roller portion, and to suppress a change in the diameter of the roller caused by the detent groove.

A perspective view showing the appearance of a three-dimensional coordinate measuring device to which the present invention is applied Front view of the three-dimensional coordinate measuring device shown in Figure 1 Assembly diagram of the drive roller Developed view of the outer peripheral surface of the shaft member developed along the rotation direction of the roller Developed view of a shaft member having only eight anti-rotation grooves in the first groove group Developed 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 respect to the rotation angle of the roller

DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-dimensional coordinate measuring device according to the present invention will be described below with reference to the accompanying drawings.

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

The three-dimensional coordinate measuring device 10 has a surface plate 14 installed on an installation surface via a pedestal 12. The surface plate 14 is made of stone such as granite or marble and has a rectangular parallelepiped shape, and has a flat upper surface 14A on which the object to be measured is placed. The upper surface 14A is arranged parallel to the X-axis and Y-axis that are orthogonal to the horizontal direction, and is arranged orthogonal to the Z-axis that is vertical.

A gate-shaped Y carriage (carriage) 16 is installed on the upper surface 14A 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 that spans the upper ends of the right Y carriage 18 and the left Y carriage 20 along the X axis direction.

The lower end of the right Y-carriage 18 is supported movably in the Y-axis direction on the side surface 14B of the surface plate 14, as shown in FIG. Supported for free movement. A driving section 24 is provided at the lower end of the right Y-carriage 18, and the driving force of this driving section 24 moves the Y-carriage 16 in the Y-axis direction. 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 section 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 section.

Further, inside the Z column 26, a columnar Z carriage 28 extending along the Z axis is supported so as to be movable in the Z axis direction, and the lower end side of the Z carriage 28 is aligned with the lower end side of the Z column 26. It is protruded from. The Z column 26 has a built-in drive section that comes into contact with the Z carriage 28, and the Z carriage 28 is moved in the Z-axis direction by the driving force of the drive section.

A measurement probe 30 such as a touch probe is attached to the lower end of the Z carriage 28 . The measurement probe 30 has, for example, a rod-shaped stylus 32 with a ball tip. The measurement probe 30 detects whether or not the tip ball of the stylus 32 is in contact with the object to be measured, and the amount of displacement of the stylus 32 caused by the contact of the tip ball of the stylus 32 with the object to be measured.

According to the three-dimensional coordinate measuring device 10 configured as described above, by moving the Y-carriage 16 in the Y-axis direction, moving the Z column 26 in the X-axis direction, and moving the Z-carriage 28 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 ball of the stylus 32 is moved along the surface of the object to be measured placed on the upper surface 14A of the surface plate 14. Then, the position of the Y carriage 16 in the Y axis direction (amount of movement), the position of the Z column 26 in the X axis direction (amount of movement), the position of the Z carriage 28 in the Z axis direction (amount of movement), and the stylus 32 at that time. By measuring the position (displacement amount) of , the three-dimensional coordinates of each position on the surface of the object to be measured are measured. Note that the process related to measuring three-dimensional coordinates is well known, so a detailed explanation will be 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 section 24 includes a roller 34 that presses against the side surface 14B of the surface plate 14. Further, the drive unit 24 has a motor 35 that rotates the roller 34, and by driving the roller 34 in the forward rotation direction and the reverse rotation direction by this motor 35, the Y carriage 16 is moved along the side surface 14B of the surface plate 14. It can be moved back and forth in the Y-axis direction.

A right Y-carriage 18 of the Y-carriage 16 is slidably supported by the surface plate 14 via a plurality of air pads. Specifically, the right Y carriage 18 is slidably supported on the upper surface 14A of the surface plate 14 via the air pad 42, and is slidably supported on the lower surface 14C 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 in between. Similarly, the left Y carriage 20 is slidably supported on the upper surface 14A of the surface plate 14 via an air pad 46. The right Y carriage 18 is slidably supported on the surface plate 14 via these air pads 42, 44, and 46, so that the Y carriage 16 is movable in the Y-axis direction with respect to the surface plate 14. Become.

FIG. 3 is an assembly diagram of the roller 34 of the drive section 24. As shown in FIG.

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

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

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

Similarly, the eight anti-rotation grooves 40B of the second groove group are formed at equal pitches P along the rotational direction A of the roller 34. Moreover, the width W in which one anti-rotation groove 40B is formed in the circumferential direction of the roller 34 is also formed to be equal, and furthermore, 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 rotational direction A of the roller 34. It is formed at an angle. Therefore, by appropriately changing the pitch P, width W, and angle α of the anti-rotation grooves 40A and 40B, the anti-rotation grooves 40A and 40B can be formed in various shapes.

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

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 rotational direction of the roller 34. The end c of the anti-rotation groove 40b is formed at a position overlapping 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 formed at a position where it overlaps the end d of the adjacent anti-rotation groove 40B. It is formed at a position overlapping in direction B with end c of 40B.

According to the drive unit 24 configured as described above, as shown in FIG. 3, since the roller 34 is constructed by mounting the roller portion 38 on the shaft member 36, the coaxiality error between the shaft member 36 and the roller portion 38 can be eliminated. be able to. Further, as shown in FIG. 4, a plurality of (16 in the embodiment) anti-rotation grooves 40A and 40B formed on the outer peripheral surface 36A of the shaft member 36 are formed at an angle with respect to the rotational direction A of the roller 34. Therefore, it is possible to suppress a change in the diameter of the roller 34 due to the formation of the anti-rotation grooves 40A, 40B on the outer circumferential surface 36A.

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 part, the rotation The amount of the roller portion that enters the stopper groove increases. This increases the amount of change in the diameter of the roller, which affects the measurement accuracy of the three-dimensional coordinate measuring device.

On the other hand, in the roller 34 of the embodiment, the anti-rotation grooves 40A and 40B formed on the outer peripheral surface 36A of the shaft member 36 are formed at an angle with respect to the rotation direction A of the roller 34, so that When the anti-rotation grooves 40A, 40B are pressed against the side surface 14B of the surface plate 14 via the roller portion 38, the amount of the roller portion 38 that enters into the anti-rotation grooves 40A, 40B is reduced. This makes it possible to suppress changes in the diameter of the roller 34 caused by the anti-rotation grooves 40A and 40B, thereby improving the measurement accuracy of the three-dimensional coordinate measuring device.

Furthermore, since the anti-rotation grooves 40A and 40B are formed at equal intervals (pitch P) along the rotation direction A of the roller 34, changes in the diameter of the roller 34 caused by the anti-rotation grooves 40A and 40B are further suppressed. It can be suppressed. Note that the anti-rotation grooves 40A and 40B do not necessarily have to be formed at equal intervals, but they should be taken into account to take into account changes 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. If so, it is preferable to form them at equal intervals. Further, the number of anti-rotation grooves 40A and 40B is not limited to eight, and for example, one anti-rotation groove may be formed in a spiral shape on the outer peripheral surface 36A of the shaft member 36. . Even if this one helical anti-rotation groove is included in the anti-rotation groove that is inclined with respect to the rotational direction of the roller.

Furthermore, the anti-rotation groove of the embodiment has a first groove group consisting of eight anti-rotation grooves 40A, a second groove group consisting of eight anti-rotation grooves 40B, and a second groove group consisting of 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 rotational 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, a modification of the anti-rotation groove formed on the outer circumferential surface 36A of the shaft member 36 will be described.

In FIGS. 3 and 4, the detent grooves have a first groove group and a second groove group, but as shown in the developed view of FIG. 5, the eight detent grooves in the first groove group A second form having only the groove 40A may be used. Similarly, a third form having only eight anti-rotation grooves 40B of the second groove group, as shown in the developed view of FIG. 6, may be used.

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

The amount of change in the diameter of the roller in the second form shown in FIG. A small amount of change e occurs at overlapping intervals of 45 degrees in direction B. The same applies to the roller of the third form shown in FIG.

On the other hand, in the conventional roller, since the anti-rotation groove is formed in a direction perpendicular to the rotational direction of the roller, a large amount of change f occurs 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 rotation prevention groove 40A or rotation prevention groove 40B, the change in the diameter of the roller 34 can be significantly suppressed compared to the conventional roller. I can do it.

On the other hand, as a modification of the second embodiment shown in FIG. 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 width W of the detent groove 40B are changed, and the end c of the detent groove 40B and the adjacent part of the detent groove 40B are The anti-rotation groove 40 is arranged so that the end portion d of the anti-rotation groove 40B does not overlap in the direction B.
B may also be formed.

According to the modification of the second embodiment and the modification of the third embodiment described above, the amount of change in the diameter of the roller can be made smaller than the amount of change e in FIG. 7 . In addition, in these modified examples, in the circumferential direction of the outer circumferential surface 36A of the shaft member 36, there are parts where the anti-rotation grooves 40A and 40B are not present, which may reduce the effect on idling, so idling cannot be reliably prevented. From the point of view, the second embodiment shown in FIG. 5 and the third embodiment shown in FIG. 6 are preferable to these modifications.

DESCRIPTION OF SYMBOLS 10... Three-dimensional coordinate measuring device, 12... Frame, 14... Surface plate, 16... Y carriage, 18... Right Y carriage, 20... Left Y carriage, 22... X guide, 24... Drive unit, 26... Z column, 28 ...Z carriage, 30...Measuring probe, 32...Stylus, 34...Roller, 35...Motor, 36...Shaft member, 36A...Outer peripheral surface, 38...Roller section, 40A...Stopping groove, 40B...Stopping groove, 42...Air pad, 44...Air pad, 46...Air pad

Claims (3)

A drive device that moves a movable body along a guide surface,
a roller that presses into contact with the guide surface;
a motor that moves the movable body along the guide surface by rotating the roller;
Equipped with
The roller includes a shaft member and a cylindrical roller portion mounted on an outer peripheral surface of the shaft member,
When the outer circumferential surface of the shaft member is unfolded along the rotational direction of the roller, a linear detent groove is arranged on the outer circumferential surface of the shaft member at an angle with respect to the rotational direction of the roller. , drive device. The drive device according to claim 1, wherein a plurality of the anti-rotation grooves are formed at equal intervals along the rotation direction of the roller. The anti-rotation groove has a first anti-rotation groove group and a second anti-rotation groove group, and the first anti-rotation groove group and the second anti-rotation groove group are arranged with respect to the rotational direction of the roller. , are inclined in opposite directions to each other at the same angle.

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