JP3430644B2 - Coordinate measuring machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate measuring machine, and more particularly to a coordinate measuring machine having a portal structure.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing a conventional coordinate measuring machine.

This coordinate measuring machine is a portal structure 1 which is movable on a surface plate 102 along a Y-axis guide 103 in the Y-axis direction.
07, an X-axis carriage 119 movable in the X-axis direction on the X-axis beam 106 of the gate structure 107, and a Z supported by the X-axis carriage 119 so as to be movable in the Z-axis direction.
The shaft spindle 125 and a probe 127 fixed to the lower end of the Z-axis spindle 125 are provided. An object to be measured is set on the surface plate 102, and the probe 127 is three-dimensionally moved with respect to the object to be measured to perform coordinate measurement on the shape and size of the object to be measured.

The gate-shaped structure 107 is a support 10 on the guide side.
4 and a support-side support 105, and an X-axis beam 106 that bridges the upper parts of both supports 104 and 105, and is an air bearing (not shown) arranged between the support 104 and the Y-axis guide 103. , And an air bearing 110 arranged between the column 105 and the surface plate 102 for floating support. Further, the X-axis beam 106 is formed with a long hole 175 extending in the X-axis direction and opened in the Z-axis direction, and the Z-axis spindle 125 penetrates the long hole 175.

The X-axis carriage 119 is connected to the traveling portion 176 and Z.
The traveling portion 176 is composed of a support portion 177 of the shaft spindle 125, and the guide portion 1 is provided on the upper surface of the X-axis beam 106.
It is guided by 78 and the guide surfaces 179 and 180 provided on both side surfaces. The support portion 177 is located above the traveling portion 176.

[0006]

As described above, in the conventional coordinate measuring machine, since the supporting portion 177 is located above the traveling portion 176, the center of gravity of the X-axis carriage 119 is correspondingly higher. A distance is generated between the point of action of each movement operation force in the X-axis direction and the Y-axis direction and the center of gravity, and when the X-axis carriage 119 is moved and operated in these directions, a movement in a direction in which the X-axis carriage 119 is tilted. Causes vibrations, resulting in deterioration of measurement accuracy of the coordinate measuring machine. Further, since the support portion 177 and the tracing stylus 127 are separated by this distance, the Z-axis spindle 125 becomes longer and rigidity decreases, and the measurement accuracy further decreases.

Further, the guide surface 179 of the X-axis beam 106,
Since the 180 and the supporting portion 177 are separated from each other, the X-axis carriage 119 has a complicated shape and structure, and it is necessary to increase the weight in order to increase the rigidity of the X-axis carriage 119.

Further, in order to guide the X-axis carriage 119, the outside of the X-axis beam 106 is guided to guide surfaces 178, 179,
Since it is used as 180, dust is easily attached to the guide surfaces 178 to 180 and scratches are easily caused. Further, since the X-axis carriage 119 is arranged so as to straddle the X-axis beam 106, there is a possibility that the operator may hit the X-axis carriage 119 when approaching the probe 127.

The present invention has been made in view of the above circumstances, and its object is to provide a coordinate measuring machine in which the measurement accuracy is kept high, the structure of the carriage is simple and compact, and the work can be performed safely. Is to provide.

[0010]

In order to solve the above-mentioned problems, a coordinate measuring machine according to a first aspect of the present invention comprises a surface plate on which an object to be measured is placed, and a pair of support members arranged on the surface plate. When,
And an X beam spanned between the support members,
A structure movable in the Y-axis direction, a Z-axis spindle having a probe, and the Z-axis spindle movably supported in the Z-axis direction, and guided in the X-beam to move in the X-axis direction. In a coordinate measuring machine provided with a possible carriage, the X-beam extends in the X-axis direction and opens in the Z-axis direction, and a space for accommodating the carriage and a carriage accommodated in the space are provided. It has a guide surface that supports the X-axis direction while guiding the Y-axis and Z-axis directions.

According to a second aspect of the coordinate measuring machine of the present invention, the X beam is composed of four guide members having guide surfaces inclined with respect to the Y and Z axes. Of these, one or two guide members on the lower side in the Z-axis direction were given higher rigidity than other guide members.

Further, in the coordinate measuring machine according to the third aspect of the present invention, the guide member has a hollow structure, and the rigidity of the guide member is substantially constant over the entire length on the guide surfaces at both ends of the guide member. Thus, a notch is provided so that a part of the carriage sinks into the guide member.

[0013]

In the coordinate measuring machine according to the first aspect of the present invention, the carriage is housed in the space of the X beam, and the movement of the carriage in the Y and Z directions is restricted by the guide surface of the X beam. ,
Since it is supported so that it can be guided in the X-axis direction, the support center of the Z-axis spindle approaches the support center of the carriage supported by the X-beam, and when the carriage moves in the X- and Y-axis directions, the carriage is moved. The movement that moves the carriage is stable because the moment that tilts down does not work.

Further, in the coordinate measuring machine according to the second aspect of the invention, the X beam is composed of four guide members having guide surfaces inclined with respect to the Y and Z axes. If one or two guide members on the lower side in the Z-axis direction are made to have higher rigidity than the other guide members, the carriage will run along the guide member having high rigidity, and The measurement accuracy depends on the straightness of the highly rigid guide member.

Further, in the coordinate measuring machine according to the third aspect of the present invention, if the guide member has a hollow structure and notches are provided in the guide surfaces at both ends of the guide member, the carriage moves to both end sides. At this time, part of the carriage can be sunk into the guide member so that the amount of deformation of the guide member can be made substantially constant over the entire length, and therefore the rigidity (strength) between the carriage and the guide member can be made substantially constant over the entire range. Can be

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a coordinate measuring machine according to a first embodiment of the present invention, FIG. 1 is a perspective view showing the whole coordinate measuring machine, and FIG. 2 is a sectional view taken along the line A--A of FIG. It is a figure.

A Y-axis guide 3 is laid on the upper surface of the surface plate 2, and an X-axis beam (X
A gate-shaped structure (structure) 7 formed by spanning beams 6 is placed. Air bearings 8 and 9 are arranged between the column 4 and the Y-axis guide 3, and an air bearing 10 is arranged between the column 5 and the surface plate 2, thus being supported by floating. The gate structure 7 includes the Y-axis guide 3
It is possible to move on the surface plate 2 in the Y-axis direction by being guided by.

The X-axis beam 6 includes support members 11 and 12 fixed to the upper portions of the columns 4 and 5, and four guide members 13, 14 and 15 whose both ends are supported by the support members 11 and 12. , 1
6 and 6. As shown in FIG. 2, these guide members 13 to 16 are inclined with respect to the horizontal plane 17 by an inclination angle θ (the inclination angle θ is preferably in the range of 45 ° to 80 °).

An X-axis carriage 19 is housed in a space 18 formed inside each of the guide members 13-16. As shown in FIG. 2, the X-axis carriage 19 is floated by an air bearing 20 along the guide surfaces 21, 22, 23 and 24 formed inside the guide members 13 to 16 so as to be movable in the X-axis direction. It is supported.

As shown in FIG. 2, a Z-axis spindle 25 is supported inside the X-axis carriage 19 via four or more air bearings 26 so as to be movable in the Z-axis direction.
The Z-axis spindle 25 penetrates the space 18 in the Z-axis direction, and a probe 27 is attached to the lower end of the Z-axis spindle 25 as shown in FIG.

As shown in FIGS. 1 and 2, the guide members 13 ...
Reference numeral 16 denotes a plate-shaped member having a rectangular cross section. However, by giving an inclination angle θ with respect to the horizontal plane 17, a force in the Z-axis direction (weight of the X-axis carriage 19 and the Z-axis spindle 25, etc.
(Z direction component force when the shaft carriage 19 falls)
Each of the guide members 13 to 16 bears the force in the Y-axis direction (the acceleration and deceleration when the gate-shaped structure 7 is moved and operated). These forces are applied to the guide members 13 to 16 as air pressure from the air bearing 20. Also,
By giving the inclination angle θ to each of the guide members 13 to 16, the X-axis beam 6 has a high section modulus, and the strength against bending moment increases.

Due to the load distribution structure and the improvement of the section modulus, the X-axis beam 6 withstands the above-mentioned force of the small number (4) of the guide members 13 to 16 and exerts sufficient rigidity, and the coordinates thereof. Keep the measurement accuracy of the measuring machine high.

Further, since the guide members 13 to 16 are inclined, the air bearing 20 is also inclined as shown in FIG. 2, and the side surface 28 of the X-axis carriage 19 is not a rectangular cross section but a bent cross section. The strength of the X carriage 1 is increased, and the air bearing 20 receives a reaction force concentrated in almost the center of the X-axis carriage 19.
9 has a structure without a free end, and has an X-axis carriage 19
The rigidity of is improved and the measurement accuracy of the coordinate measuring machine is improved.

Further, since the guide member 13 and the guide member 15 and the guide member 14 and the guide member 16 are vertically separated from each other and the X-axis carriage 19 has a vertically long structure, the Z-axis spindle by the air bearing 26 is provided. It becomes possible to widen the distance between the support points of 25, and the rigidity of the Z-axis spindle 25 in the X and Y axis directions increases, and the measurement accuracy of the coordinate measuring machine increases.

Further, the rigidity of each of the guide members 13 to 16 decreases from both end sides supported by the support members 11 and 12 toward the central portion, and the gap with the air bearing 20 widens, but the guide members 13 to 16 respectively. If the rigidity of 16 and the air bearing 20 are made substantially uniform, the X-axis carriage 1
9 does not follow a specific guide member, but follows all of the guide members 13-16. Therefore, the guide surfaces 21 to
Even if all 24 straightnesses are not processed with high accuracy, these straightnesses are averaged to be highly accurate as a whole, and high measurement accuracy can be obtained at low cost.

The X-axis carriage 19 has a structure in which the support portion (air bearing 26) of the Z-axis spindle 25 is arranged inside the support portion (air bearing 20) by the X-axis beam 6, which is different from the conventional example. Unlike the above, the support part and the running part are not a two-layer structure in which they are vertically separated. Therefore, the X-axis carriage 19 has a simple shape and structure, can be made compact, and it is not necessary to increase the rigidity to compensate for the weaknesses of the two-layer structure, so that an increase in weight can be avoided.

Further, since the guide surfaces 21 to 24 for guiding the X-axis carriage 19 are provided inside the X-axis beam 6, dust and scratches are less likely to occur and the measurement accuracy of the coordinate measuring machine is kept high. Be drunk Further, since the X-axis carriage 19 runs inside the X-axis beam 6, the worker does not hit the X-axis carriage 19 even when working near the probe 27.

FIG. 3 is a sectional view showing a main part of a coordinate measuring machine according to a second embodiment of the present invention. 3 is a diagram corresponding to FIG. 2 in the first embodiment. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The X-axis beam of the coordinate measuring machine of this embodiment is
A support member 30 fixed to the upper part of one of the columns 4 and another support member fixed to the upper part of the other column 5 (not shown)
And eight guide members 31, 32, 33, 34, 35, 36, 37, 38 whose both ends are supported by these support members.

An X-axis carriage 40 is housed in a space 39 formed inside each of the guide members 31 to 38. X
The shaft carriage 40 uses the air bearing 20 to guide the guide surfaces 41, 42, 43, 44 inside the guide members 31 to 38.
It is floatingly supported so as to be movable in the X-axis direction along 45, 46, 47 and 48.

The guide members 33 to 36 are the X-axis carriage 40.
In the Y direction, and the guide members 31, 32, 37, 38 constrain the X-axis carriage 40 in the Z-axis direction.

A Z-axis spindle 25 is supported inside the X-axis carriage 40 via four or more air bearings 26 so as to be movable in the Z-axis direction. The Z-axis spindle 25 penetrates the space 39 in the Z-axis direction, and a probe 27 is attached to the lower end of the Z-axis spindle 25.

In the coordinate measuring machine of this embodiment, eight guide members are used as described above, and each of the guide members 31 to 38 bears only the force in the Y-axis direction or the Z-axis direction. It is made up of 8 air bearings.
It is used individually. Therefore, each guide member 31-38
The load on the air bearing 20 and the air bearing 20 is reduced by that much, and the X-axis beam 4 is provided by such a load distribution structure.
0 Overall rigidity and air bearing 20 rigidity have increased,
The measurement accuracy of the coordinate measuring machine is improved accordingly.

Further, the guide member 33 and the guide member 35, and the guide member 34 and the guide member 36 are vertically separated from each other, and the X-axis carriage 40 has a vertically long structure, and the Z-axis spindle 25 is supported by the air bearing 26. Since the point interval is widened, the rigidity of the Z-axis spindle 25 in the X- and Y-axis directions increases, and the measurement accuracy of the coordinate measuring machine increases.

Further, if the rigidity of each of the guide members 31 to 38 and the air bearing 20 is made substantially uniform, X
Since the shaft carriage 40 moves following the guide members 31 to 38, the straightness of each of the guide surfaces 41 to 48 is averaged, and the overall accuracy is high, even if all the straightnesses of the guide surfaces 41 to 48 are not processed with high accuracy. High measurement accuracy can be obtained at low cost.

Further, since the X-axis carriage 40 does not have a two-layer structure unlike the conventional example, it has a simple shape and structure and can be made compact, and it is necessary to increase the rigidity to compensate for the weak points of the two-layer structure. Since it does not exist, the increase in weight can be avoided.

Further, guide surfaces 41 to 48 for guiding the X-axis carriage 40 are provided inside the X-axis beam so that dust and scratches are less likely to occur and the measurement accuracy of the coordinate measuring machine is kept high. Be done. Further, since the X-axis carriage 40 travels inside the X-axis beam, even if an operator works near the probe, the X-axis carriage 40 does not hit.

FIG. 4 is a sectional view showing a main part of a coordinate measuring machine according to a third embodiment of the present invention. FIG. 4 is a drawing corresponding to FIG. 2 in the first embodiment. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The X-axis beam of the coordinate measuring machine of this embodiment is
A support member 50 fixed to the upper part of one of the columns 4 and another support member fixed to the upper part of the other column 5 (not shown)
And four guide members 51, 52, 53, 54 whose both ends are supported by these supporting members.

The X-axis carriage 19 is housed in the space 55 formed inside each of the guide members 51 to 54. X
The shaft carriage 19 is rotatably supported by the air bearing 20 so as to be movable in the X-axis direction along the guide surfaces 56, 57, 58 and 59 inside the guide members 51 to 54.

A Z-axis spindle 25 is supported inside the X-axis carriage 19 via four air bearings 26 so as to be movable in the Z-axis direction.

As shown in FIG. 4, the guide members 51 to 54 are plate members having a rectangular cross section, and are inclined by an inclination angle θ with respect to the horizontal plane 17. The rigidity of the guide member 54 arranged on the lower one side is made higher by making the plate thickness T1 thicker than the plate thickness T2 of the other guide members 51, 52, 53.

Therefore, since the X-axis carriage 19 moves (as a reference) following the guide surface 59 of the guide member 54 having high rigidity, the measurement accuracy of the coordinate measuring machine is determined by the guide member 5.
It depends on the straightness of 4. As a result, by processing only the straightness of the highly rigid guide member 54 with high accuracy, it is possible to increase the measurement accuracy of the coordinate measuring machine at low cost.

The measuring accuracy of the coordinate measuring machine is determined by the guide member 5.
In order to depend on the straightness of No. 4, the rigidity of the guide member 54 is made higher than that of the air bearing 20, and the rigidity of the guide members 51 to 53 is ⅕ of the rigidity of the air bearing 20.
It is desirable to make it lower than zero.

Further, the inclination angle θ is given to each of the guide members 51 to 54, and the support portion of the Z-axis spindle 25 is attached to the X-axis carriage 1.
9 and the X-axis carriage 19 is run inside the X-axis beam, the rigidity of each member is increased in the coordinate measuring machine like the coordinate measuring machine of the first embodiment described above. The measurement accuracy is high, the structure is simple and lightweight, and the guide surfaces 56 to 59 are unlikely to be dusted or scratched, so that the measurement accuracy is kept high. Further, similarly to the first embodiment, the worker does not hit the X-axis carriage 19 even when working near the probe.

FIG. 5 is a sectional view showing a main part of a coordinate measuring machine according to a fourth embodiment of the present invention. FIG. 5 corresponds to FIG. 2 in the first embodiment. The same parts as those in the third embodiment of FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG. 5, both of the lower guide members 53 and 54 are made thicker than the upper guide members 51 and 52 by a plate thickness T1. It has high rigidity. Since the X-axis carriage 19 moves following the guide member 54 having high rigidity, and the measurement accuracy of the coordinate measuring machine is determined by the straightness of the guide members 53, 54, only the straightness of the guide members 53, 54 is processed with high accuracy. Just keep it.

According to the coordinate measuring apparatus of the fourth embodiment,
The same effect as that of the third embodiment of FIG. 4 can be obtained.

FIG. 6 is a sectional view showing a main part of a coordinate measuring machine according to a fifth embodiment of the present invention, which corresponds to FIG. 2 in the first embodiment. FIG. 7 is a view taken along the line BB of FIG.
The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG. 6, the guide members 64, 65, 66, 67 are hollow plate-shaped members,
It is inclined by an inclination angle θ with respect to the horizontal plane 17. Further, as shown in FIG. 7, the guide surfaces 69 of the guide members 64-67,
A notch 73 is provided at both ends of each of 70, 71, 72, and a flexible cantilever portion 74 is formed by the notch 73. By providing the cantilever portion 74, the rigidity of each of the guide members 64-67 becomes substantially uniform over the entire length.

Therefore, even if the load capacity of the air bearing 20 is increased and the rigidity of the X-axis carriage 19 is increased,
When the X-axis carriage 19 moves to both ends of the X-axis beam, the guide surfaces 69 to 72 and the air bearing 20 are prevented from coming into contact with each other by the appropriate depression of the cantilever portion 74.

[0053]

As described above, according to the coordinate measuring machine of the first aspect of the present invention, the carriage is housed in the space of the X beam, and the carriage is provided with Y and Z on the guide surface of the X beam.
Since the support is provided so as to be guided in the X-axis direction while restricting the movement in the axial direction, the support center of the Z-axis spindle and the support center of the carriage supported by the X-beam come close to each other, and the carriage moves in the X-axis direction. In addition, when moving in the Y-axis direction, the movement that tilts the carriage does not work, the movement movement of the carriage is stable, and the measurement accuracy is improved. Further, since the carriage moves within the space inside the X beam, when an operator approaches the stylus or the like, the operator does not accidentally hit the carriage. Further, since the guide surface of the X-beam is desired to be on the space side, dust and scratches are unlikely to occur, and high measurement accuracy can be maintained. Further, since the portion supporting the Z-axis spindle and the guide surface of the X beam are close to each other, it is not necessary to increase the weight of the carriage, and the shape and structure of the carriage can be simplified.

According to the coordinate measuring machine of the second aspect of the present invention, the X beam is composed of four guide members having guide surfaces inclined with respect to the Y and Z axes, and the four guide members are provided. If one or two guide members on the lower side in the Z-axis direction are given higher rigidity than other guide members, the carriage travels along the guide member having high rigidity,
The measurement accuracy of the coordinate measuring machine is determined by the straightness of the highly rigid guide member. If only the straightness of the highly rigid guide member is processed with high accuracy, high measurement accuracy can be obtained at low cost. .

Further, according to the coordinate measuring machine of the third aspect of the present invention, if the guide member has a hollow structure and notches are provided in the guide surfaces at both ends of the guide member, the carriage moves to both end sides. When moved, part of the carriage can be sunk into the guide member, and the amount of deformation of the guide member can be made substantially constant over the entire length. Therefore, the rigidity (strength) between the carriage and the guide member can be reduced over the entire range. Can be nearly constant over time.

[Brief description of drawings]

FIG. 1 is a perspective view showing a coordinate measuring machine according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing a main part of a coordinate measuring machine according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of a coordinate measuring machine according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing a main part of a coordinate measuring machine according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a main part of a coordinate measuring machine according to a fifth embodiment of the present invention.

FIG. 7 is a view taken along the line BB of FIG.

FIG. 8 is a perspective view showing a conventional coordinate measuring machine.

[Explanation of symbols]

2 Surface plate 6 X-axis beam 7 Gate type structure 11, 12 Support members 13, 14, 15, 16, 31, 32, 33, 34, 3
5, 36, 37, 38, 51, 52, 53, 54, 6
4, 65, 66, 67 Guide member 18, 39, 55, 62, 68 Space 19, 40 X-axis carriage 21, 22, 23, 24, 41, 42, 43, 44, 4
5,46,47,48,56,57,58,59,6
9, 70, 71, 72 Guide surface 25 Z-axis spindle 27 Measuring element 73 Notch

Claims (3)

(57) [Claims] 1. A surface plate on which a measured object is placed, a pair of support members arranged on the surface plate, and an X beam spanned between the support members, and in the Y-axis direction. And a Z-axis spindle having a tracing stylus, and a carriage that supports the Z-axis spindle so as to be movable in the Z-axis direction and is movable in the X-axis direction while being guided by the X-beam. In the coordinate measuring machine, the X-beam extends in the X-axis direction and opens in the Z-axis direction, and the space for accommodating the carriage and the carriage accommodated in the space are Y and Z. A coordinate measuring machine, comprising: a guide surface that supports a guide in the X-axis direction while restricting movement in the axial direction. 2. The X beam is composed of four guide members having guide surfaces inclined with respect to the Y and Z axes, and one or two of the four guide members on the lower side in the Z axis direction. The coordinate measuring machine according to claim 1, wherein one guide member has higher rigidity than the other guide member. 3. The guide member has a hollow structure, and a part of the carriage is provided in the guide member on the guide surfaces at both ends of the guide member so that the rigidity of the guide member is substantially constant over the entire length. The coordinate measuring machine according to claim 1 or 2, further comprising a notch that sinks in.