JPH023924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a coordinate measuring machine. More specifically, the present invention relates to a three-dimensional measuring machine that has an air balance function to balance the weight of the Z-axis using air, and has a safety function that prevents the Z-axis from falling by itself due to loss of air or the like.

[Background technology and its problems] A touch signal probe, a tool microscope, etc. (hereinafter abbreviated as a measuring head, etc.) and a workpiece on a stage are moved relative to each other in a three-dimensional direction, and the relative In the case of a coordinate measuring machine that measures the shape of a workpiece based on the amount of displacement, the Z-axis structure that holds the measuring element etc. is slid against the stationary part of the main body in order to move the measuring element etc. with a relatively light force. Models are emerging that allow movable guidance and balance the weight of the Z-axis structure using air.

The present applicant has proposed, for example, Japanese Patent Laid-Open No. 59-40101 regarding this type of air balance device.
However, these conventional air balance devices
If the supply air pressure fluctuates or is lost, there is a problem that the Z-axis structure including the probe etc. will fall, so it has been necessary to separately provide an electromagnetic brake that is activated when the compressor is stopped, for example.

Such a safety device prevents the electromagnetic brake from working even if, for example, a leak occurs in the air piping that supplies air from the compressor to the air balance device and the pressure inside the air balance device decreases. Since an electric circuit must be installed separately from the air circuit of the device, the measuring device itself has the disadvantage of being complicated and expensive.

[Object of the Invention] An object of the present invention is to provide a three-dimensional measuring machine that can safely and reliably prevent the Z-axis from falling with a relatively simple configuration.

[Means and effects for solving the problem] Therefore, the present invention provides a cylinder that utilizes a hollow portion of a Z-axis structure that is provided with a probe etc. at its lower end and is slidably guided in the vertical direction. , a three-dimensional measuring machine equipped with an air balance device consisting of a piston housed in the cylinder, and a lock pin that is always biased in one direction by a spring on the Z-axis structure; a locking member having a plurality of locking holes having a diameter corresponding to the lock pin along the sliding direction of the Z-axis structure; Abnormality detection in which when the pressure inside the cylinder of the air balance device drops by a predetermined value, the air supply to the cylinder device is cut off and the lock pin is inserted into one of the locking holes of the locking member by the biasing force of a spring. It is characterized by being equipped with a valve device.

[Example] FIG. 2 shows the appearance of a coordinate measuring machine of this example. In this three-dimensional measuring machine, a horizontal beam 3 is sent to the slider 4 along the horizontal beam 3 in the front-rear direction (Y-axis direction) of the surface plate 1 via supports 2A and 2B provided on both sides of the surface plate 1. is moved in the left-right direction (X-axis direction) of the surface plate 1, and a Z-axis structure 6 having a touch signal probe, a tool microscope, etc. (hereinafter abbreviated as a probe, etc.) 5 at the lower end of the slider 4 is attached to the surface plate 1. 1
are provided so as to be movable in the vertical direction (Z-axis direction). That is, the measuring element 5 is provided so as to be movable in three-dimensional directions via these three-dimensional measuring machines. Furthermore, when the measuring element etc. 5 is moved in a three-dimensional direction and comes into contact with an object to be measured (not shown) placed on the surface plate 1, the position of the horizontal beam 3 in the Y-axis direction, the position of the slider 4 in the X-axis After the position in the Z-axis direction and the position of the Z-axis structure 6 in the Z-axis direction are detected by detectors (not shown), they are respectively displayed on a display.

As shown in FIG. 3, the internal structure of the Z-axis structure 6 includes a holding frame 11 that is integrally formed at the upper and lower positions of the front surface of the slider 4, and has a circular hollow hole 12 extending toward the central axis. A square columnar shaft member 13 is held movably up and down, ie, movable in the Z-axis direction. Between the shaft member 13 and the holding frame 11, a fourth
As shown in the figure, the air pads 14 that blow out compressed air against the four outer surfaces of the shaft member 13 are attached to the bolt 15.
are held through each. In addition, shaft material 1
3 is provided with a holder 16 at its lower end for attaching the measuring element 5, and an air balance device 17 is provided inside the hollow hole 12.

The air balance device 17 includes the shaft member 13
A cylinder 19 fitted into the hollow hole 12 and integrally connected to the shaft member 13 via the connecting plate 18
A piston 21 is slidably fitted into the cylinder 19, a cylinder head 20 is fitted onto the upper end of the cylinder 19, and the cylinder head 20 passes through the center and its lower end is connected to the piston 2.
1 and a piston rod 22 connected to the piston rod 22. The upper end of the piston rod 22 projects upward through an insertion hole 24 of a bracket 23 fixed to the slider 4 via a locking member 41. At the end of the piston rod 22 protruding upward from the bracket 23, there is a flange plate 2 supported on the upper surface of the bracket 23 via a bearing 25.
6 is fixed by a nut 27. In other words,
The upper end of the piston rod 22 is supported by a bracket 23 so as to be movable in the radial direction of the cylinder 19.

Further, the locking member 41 has a plurality of locking holes 4 along the sliding direction of the shaft member 13, that is, the Z-axis direction.
2 are provided at regular pitch intervals, and
An abnormality detection valve device 61 is attached via a bracket 43. On the other hand, on the connection board 18,
As shown in FIG. 5, a lock pin 52 is supported horizontally via two bearings 51 and is movable in a direction perpendicular to the surface of the locking member 41 in which the locking hole 42 is formed. , this lock pin 5
A cylinder device 53 operated by the abnormality detection valve device 61 is installed parallel to the cylinder device 2 . The lock pin 52 has a distal end portion, that is, the locking member 41
A strong friction material is attached to the portion inserted into the locking hole 42 of the locking member 41 , and a spring 54 holds the locking member 41 in place.
The piston rod 56 of the cylinder device 53 is constantly biased in the direction of insertion into the locking hole 42 of the cylinder device 53, and is connected to the piston rod 56 of the cylinder device 53 via a connecting piece 55. As a result, the lock pin 52 is displaced in the direction of being removed from the locking hole 42 against the spring 54 while the cylinder device 53 is in operation (the piston rod 56 is advanced).
In the released state, the locking hole 4 is closed by the spring 54.
It is designed to be inserted into 2.

Further, the cylinder head 20 is provided with two connection holes 28 and 29. An air supply circuit 30 is connected to one of the connection holes 28 . Further, the abnormality detection valve device 61 is connected to the other connection hole 29 .

As shown in FIG. 1, the air supply circuit 30 is configured such that air at a constant pressure, for example, 5 kg·f/cm ² , supplied from a high-pressure air pressure source 31 passes through an air filter 32 and a micro-mist separator 33 to an air regulator. 34. The air regulator 34 has a secondary side connected to the air pad 14, the flow rate adjustment pressure reducing valve 35, and the abnormality detection valve device 61, respectively, and maintains the pressure on the secondary side at a set pressure, for example, 4 kg·f/cm ^{2 .} It is becoming more and more like this. The flow rate adjustment pressure reducing valve 35 has a secondary side connected to the inside of the cylinder 19 and the abnormality detection valve device 61.
connected to and the pressure on the secondary side, i.e. cylinder 1
The pressure inside 9 is maintained at a set pressure, for example, 2 kg·f/cm ² .

On the other hand, the abnormality detection valve device 61 is constructed as shown in FIG. That is, inside the valve box 62, a first chamber 63 is formed in the upper part thereof, and a second chamber 65, which communicates with the first chamber 63 through the communication hole 64, is formed in the center part. With,
A three-way valve 66 is provided at the bottom.

In the first chamber 63, a pressure setting screw shaft 71, which is rotatably supported on the upper surface of the valve box 62 but not displaceable in the axial direction, is faced in the center thereof, and a pressure setting screw shaft 71 is supported in the middle in the vertical direction. Two diaphragms 75 and 76 are provided at two locations to divide the first chamber 63 into three chambers 72, 73, and 74, respectively. The pressure setting screw shaft 71 is provided with a spherical valve 77 at its tip, and its rotation is restricted by a rotation stopper 78.
A threaded bush 79 that is displaceable in the axial direction is screwed therein. A piece 80 fixed to the center of the upper diaphragm 75 is fitted into the threaded bush 79 so as to be displaceable in the axial direction. On the other hand, a valve seat 81 is fixed to the center of the lower diaphragm 76. A through hole 82, which is closed by the valve 77, is formed in the center of the valve seat 81 and extends through the upper and lower surfaces thereof. Further, between the upper surface of the valve seat 81 and the lower surface of the piece 80, a spring 83 is provided between the lower surface of the valve seat 81 and the bottom wall of the first chamber 63. A spring 84 that biases the valve seat 81 upward is interposed in each of the valve seats 81 and 84 . Furthermore, a supply hole 8 is provided in the peripheral wall of each chamber 72 for introducing the secondary air of the flow rate adjustment pressure reducing valve 35 into each chamber 72.
5, an air release hole 86 is formed in the peripheral wall of each chamber 73, and a supply hole 87 is formed in the peripheral wall of each chamber 74 for introducing the air pressure inside the cylinder 19 into each chamber 74.

Further, the second chamber 65 is provided with a diaphragm 93 that partitions the chamber 65 into upper and lower chambers 91 and 92. An atmosphere opening hole 94 is bored in the peripheral wall of each chamber 92. Further, the upper end of a drive rod 95 provided at the center of the valve box 62 and movable in the axial direction is integrally attached to the diaphragm 93. The drive rod 95 is urged toward each chamber 74 by a spring 96.

The three-way valve 66 also has an input port 101, an output port 102, and an atmosphere release port 103 formed on the peripheral wall of the valve box 62, and a valve seat 105 formed in the middle of a flow path 104 that communicates these with each other. , is biased by the spring 106 in a direction to close the valve seat 105, and is biased by the drive rod 95 to close the valve seat 105.
The valve 10 is displaced in a direction opposite to the biasing direction of the valve 10.
It consists of 7. The input port 101 is connected to the primary side of the flow rate regulating pressure reducing valve 35, and the output port 102 is connected to the cylinder device 53. Here, when the valve 107 is in the state shown in FIG. 6, the input port 101 and the output port 102 are in communication with each other. Then, the primary side of the flow regulating pressure reducing valve 35 is supplied into the cylinder device 53 through the input port 101 and the output port 102, so that the lock pin 52 is disengaged from the locking hole 42. On the other hand, valve 10
7 closes the valve seat 105, the input port 10
1 is closed, and the output port 102 is opened to the atmosphere 103.
will be communicated with. Then, the air in the cylinder device 35 is discharged to the atmosphere through the output port 102 and the atmosphere opening 103, and as a result, the lock pin 52 is released from the spring 5.
4, it is inserted into the locking hole 42.

Next, the operation of this embodiment will be explained. First, the flow rate adjustment pressure reducing valve 35 is adjusted, and the flow rate adjusting pressure reducing valve 35 is adjusted.
6 is set to a pressure commensurate with the weight of the Z-axis structure 6. Now, the shaft material 13, holder 16, probe etc. 5, cylinder 19 and cylinder head 2
The total weight of the Z-axis structure 6 including 0 etc. is M [Kg・
f], and the inner diameter (diameter) of the cylinder 19 is D [mm], then the pressure P inside the cylinder 19 is P=4M/πD ² [Kg·f/cm ² ].

Therefore, the pressure on the secondary side of the flow rate regulating pressure reducing valve 35 is set to pressure P. As a result, the flow rate adjustment pressure reducing valve 3
The secondary pressure P of 5 is supplied into the cylinder 19 and is also supplied to each chamber 72 through the supply hole 85 of the abnormality detection valve device 61. On the other hand, cylinder 1
9 is applied to each chamber 74 through the supply port 87 of the abnormality detection valve device 61 as a signal pressure.

Here, if the pressure setting screw shaft 71 of the abnormality detection valve device 61 is rotated in advance and the compression force of the spring 83 is set to be balanced with the signal pressure in each chamber 74, the lower surface of the diaphragm 76 The force due to the signal pressure and the repulsive force of the spring 84 (this is a preload to prevent the signal pressure from decreasing below the set pressure due to minute fluctuations in the signal pressure) are combined, and the repulsive force of the spring 83 acts on the upper surface. As a result, the diaphragm 76 is pushed upward in FIG. Then, as the diaphragm 76 is pushed up, the through hole 82 is closed by the valve 77, and as a result, the signal pressure in each chamber 74 enters each chamber 91 through the communication hole 64, causing the diaphragm 93 to move downward in FIG. Press down. When the diaphragm 93 is pushed down, the valve 107 is moved by the spring 10 via the drive rod 95.
As a result of being released from the valve seat 105 against the pressure 6, the input port 101 and the output port 102 are communicated with each other.

Thereby, the secondary side pressure of the regulator 34 is supplied to the cylinder device 53. Cylinder device 5
When air is supplied to 3, the piston rod 5
6 advances, and the connecting piece 5 is attached to the piston rod 56.
A lock pin 52 connected through a spring 54
Since it is displaced upward in FIG. 5 against this, the Z-axis structure 6 can be moved up and down.

Measurement is performed in this state. When making measurements, hold the lower end of the Z-axis structure 6 with your hand and use the measuring tip 5.
are moved in three-dimensional directions and brought into contact with the object to be measured one after another. Then, the positions in the X-, Y-, and Z-axis directions where the contact point etc. 5 has come into contact with the object to be measured are detected by detectors (not shown) and then displayed on a display or the like.

At this time, when the shaft member 13 of the Z-axis structure 6 is raised, the volume within the cylinder 19 increases and the pressure within the cylinder 19 begins to decrease. At this time, when the downstream pressure of the flow rate adjustment pressure reducing valve 35 decreases below the set pressure due to a decrease in the pressure inside the cylinder 19, the built-in valve operates in the direction of opening, and the secondary side pressure, that is, the inside of the cylinder 19 increases. Maintain the pressure at the set pressure.

On the other hand, when the shaft member 13 is lowered from the balanced state, the volume within the cylinder 19 decreases and the pressure within the cylinder 19 begins to rise. At this time,
In the flow rate adjustment pressure reducing valve 35, when the secondary pressure rises above the set pressure, the built-in valve operates in the direction of closing and releases excess air to the outside, thereby reducing the pressure in the cylinder 1.
9 is maintained at the set pressure. in this way,
Since the weight of each member constituting the Z-axis structure 6 is balanced by air pressure, the Z-axis structure 6 can be operated up and down with a relatively light force during measurement.

During this measurement, when various types of probes etc. 5 are attached to the holder 16 for each measurement item, the probes etc. 5 are attached to the holder 16.
Since the total weight changes according to the total weight, it is necessary to change the pressure inside the cylinder 19 according to the total weight. Therefore, the secondary pressure of the flow rate adjustment pressure reducing valve 35 is set to a pressure commensurate with the total weight, and the secondary pressure is supplied to the cylinder 19 to maintain balance. room 72
also supplied.

At this time, the screw bush 79 is fixed, but the air pressure supplied into each chamber 72 acts on the piece 80 via the diaphragm 75, so the spring 83 is compressed according to the displacement of the piece 80. . Therefore, even if the total weight changes due to the gauge head etc. 5 attached to the holder 16, and the secondary side pressure of the flow rate adjustment pressure reducing valve 35 is changed according to the total weight,
Since the compressive force of the spring 83 changes according to the secondary pressure, the input port 101 and the output port 102 remain in communication with each other when the signal pressure is higher than the set pressure, as described above.

If the signal pressure drops below the set pressure due to some reason, such as a leak in an air pipe, the diaphragm 76 is pushed down. Then, the valve seat 81
Since the through hole 82 is released from the valve 77, the air in each chamber 74 enters each chamber 73 through the through hole 82 and is discharged from the atmosphere opening hole 86. Therefore,
As a result of the drive rod 95 being pushed up by the spring 96,
The valve 107 interrupts the circuit that has been connected until now by the spring 106, and connects the output port 102 and the atmosphere release port 10.
3.

As a result, the secondary side pressure of the regulator 34 is no longer supplied to the cylinder device 53, and
Cylinder device 53 is released to the atmosphere. As a result, the lock pin 52 is moved to the fifth position by the action of the spring 54.
It is displaced downward in the figure and inserted into one of the locking holes 42 of the locking member 41. Therefore, cylinder 19
When the internal pressure drops below the set pressure, lock pin 5
2 enters the locking hole 42, and the Z-axis structure 6 is prevented from falling.

Therefore, according to this embodiment, when the total weight of the members constituting the Z-axis structure 6 is balanced by the air pressure of the cylinder device 17, the pressure inside the cylinder 19 of the air balance device 17 is reduced by a predetermined value. When the cylinder device 53 is released by the abnormality detection valve device 61, the lock pin 52 is released by the spring 54.
Due to the action of the locking hole 4 of the locking member 41
2, it is possible to prevent the Z-axis structure 6 from falling due to a drop in the pressure inside the cylinder 19 with a relatively simple configuration including only an air circuit. Moreover, the cylinder 1 of the cylinder device 17
Since the pressure inside cylinder 9 is detected, that cylinder 1
Even if, for example, a leak occurs in the piping that supplies air to the Z-axis structure 6, it is possible to safely and reliably prevent the Z-axis structure 6 from falling.

In addition, the cylinder device 53 and the lock pin 52
Since the structure is such that the locking member 41 is provided on the Z-axis structure 6 side and the locking member 41 is provided on the main body side (in this case, the slider 4), the overall structure has the advantage of being small and inexpensive. Furthermore, the tip portion of the locking pin 52, that is, the portion inserted into the locking hole 42 of the locking member 41, includes:
Because the strong friction material is attached, the locking member 41
Wear of the lock pin 52 due to sliding contact with the lock pin 52 can be prevented.

Further, the abnormality detection valve device 61 controls the pressure inside the cylinder 19 of the air balance device 17 to the Z-axis structure 6.
Flow rate adjustment pressure reducing valve 3 to set the pressure commensurate with the weight of
The pressure immediately after the secondary side output of No. 5 is compared with the pressure inside the cylinder 19, and the cylinder device 53 is released when the pressure inside the cylinder 19 decreases by a predetermined value with respect to the pressure immediately after the secondary side output. Even if the air pressure source side changes temporarily, the cylinder device 53 is not released, so there is no interruption of measurement work due to this.

Also, by replacing the probe etc. 5, the Z-axis structure 6
When the weight of the cylinder 19 changes and the secondary side pressure of the flow rate regulating pressure reducing valve 35 changes according to the weight, the amount of compression of the spring 83 that is balanced with the pressure inside the cylinder 19 changes depending on the secondary side output. Therefore, even if the flow rate adjustment pressure reducing valve 35 is changed, there is no need to finely adjust the pressure setting screw shaft 71 that adjusts the compression force of the spring 83. Therefore, it is only necessary to adjust the pressure reducing valve 35, and therefore the adjustment is not necessary. It's easy. Furthermore, the set value can be minutely controlled by the pressure setting screw shaft 71.

In the above embodiment, the abnormality detection valve device 61 compares the pressure immediately after the secondary side output of the flow rate adjustment pressure reducing valve 35 with the pressure inside the cylinder 19, but the pressure inside the cylinder 19 is simply detected. However, the cylinder device 53 may be released in accordance with the detected pressure.

Further, in the above embodiments, the object is a three-dimensional measuring machine for manual testing, but the present invention may be one that automatically drives the measuring stylus etc. according to a predetermined procedure.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a three-dimensional measuring machine that can safely and reliably prevent the Z-axis from falling with a relatively simple configuration.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is an overall system diagram, Fig. 2 is a perspective view of a three-dimensional measuring machine,
Fig. 3 is a sectional view showing the internal structure of the Z-axis structure, Fig. 4 is a sectional view taken along the - line in Fig. 3, Fig. 5 is a sectional view taken along the - line in Fig. 3, and Fig. 6 is a sectional view taken along the - line in Fig. 3. FIG. 3 is a cross-sectional view showing the internal structure of. 5... Measuring head etc., 6... Z-axis structure, 17...
Air balance device, 19...Cylinder, 21...
... Piston, 41 ... Locking member, 42 ... Locking hole, 52 ... Lock pin, 53 ... Cylinder device, 54 ... Spring, 61 ... Abnormality detection valve device.

Claims (1)

[Scope of Claims] 1. A cylinder that utilizes the hollow part of a Z-axis structure that is provided with a measuring element, etc. at its lower end and is slidably guided in the vertical direction, and a piston that is housed within this cylinder. In a coordinate measuring machine equipped with an air balance device, the Z-axis structure includes a lock pin that is always biased in one direction by a spring, and a lock pin that is pulled back in a direction opposite to the biasing force of the spring. and a locking member having a large number of locking holes having diameters corresponding to the lock pins along the sliding direction of the Z-axis structure, so that the pressure in the cylinder of the air balance device is maintained at a predetermined level. The tertiary device is characterized by being provided with an abnormality detection valve device that cuts off the air supply to the cylinder device and inserts the lock pin into any of the locking holes of the locking member by the biasing force of a spring when the value decreases. Original measuring machine. 2. The three-dimensional measuring machine according to claim 1, characterized in that a strong friction material is attached to the tip of the lock pin. 3. The three-dimensional measuring machine according to claim 1 or 2, wherein the locking holes are provided at regular pitches along the sliding direction of the Z-axis structure. 4. In any one of claims 1 to 3, the abnormality detection valve device is configured to control the secondary air pressure of an air supply circuit that supplies air to the cylinders of the air balance device and the cylinders of the air balance device. The three-dimensional measuring machine is configured to compare the pressure within the cylinder and cut off air supply to the cylinder device when the pressure within the cylinder decreases by a predetermined value with respect to the secondary air pressure. .