JP6948928B2 - Spindles and machine tools - Google Patents

Description

The present invention relates to a spindle device and a machine tool, and more particularly to a spindle device and a machine tool having a spindle capable of mounting a sensor for measuring a workpiece instead of a tool.

Conventionally, there is known a spindle device provided with a spindle on which a sensor for measuring a workpiece can be attached instead of a tool (see, for example, Patent Document 1).

Patent Document 1 discloses a spindle device including a spindle, a bearing that rotationally supports the spindle, a motor that rotationally drives the spindle, and a tool clamp mechanism provided at the tip of the spindle. At the tip of the spindle, either a tool for machining a work or a measuring head for measuring the diameter of a machined portion of the work can be exchanged and attached / detached by a tool clamp mechanism.

Although not specified in Patent Document 1, the bearing of the spindle is considered to be a contact type ball bearing.

Japanese Unexamined Patent Publication No. 2006-326804

Here, as the bearing of the spindle device, a non-contact bearing such as a hydrostatic fluid bearing may be adopted in addition to a contact type rolling bearing such as a ball bearing. Compared to contact type bearings, non-contact bearings have a smaller coefficient of friction and less heat generation, but have lower bearing rigidity, and the spindle is easily moved by the gap between the bearing and the bearing due to external force. Therefore, in a spindle device that uses non-contact bearings, when a contact sensor is attached to the spindle as a measurement head to measure the work, the spindle is displaced due to the contact reaction force from the work, and accurate measurement is performed. There is a problem that it becomes difficult. Therefore, in a spindle device that employs a non-contact bearing, it is desired that the measurement accuracy can be improved even when the contact sensor is mounted on the spindle to measure the workpiece.

The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to mount a contact sensor on a spindle in a spindle device using a non-contact bearing to measure a work. Even if it is done, it is to provide a spindle device and a machine tool capable of improving the measurement accuracy.

The spindle device according to the first aspect of the present invention is provided at one end of the spindle, a non-contact bearing that rotatably supports the spindle around the central axis in a non-contact manner, a drive unit that drives the spindle to rotate, and one end of the spindle. The non-contact bearing is provided with a tool holding portion that detachably holds a tool for processing the work or a contact sensor for measuring the work, and the non-contact bearing supports the main shaft in a contact state when the contact sensor is mounted. It is configured to be switchable to the measurement state that suppresses the movement of the bearing.

In this spindle device, by configuring the non-contact bearing as described above, when the contact sensor is attached to the tool holding portion to measure the workpiece, the non-contact bearing is switched to the measurement state and the non-contact bearing is used. The spindle can be supported in contact. Therefore, when the contact reaction force of the contact sensor acts on the spindle, the displacement of the spindle due to the contact reaction force can be suppressed as compared with the case where the spindle is held in the non-contact state. There are various methods for suppressing misalignment depending on the relationship between the contact direction between the non-contact bearing and the spindle and the action direction of the contact reaction force. There is an increase in frictional resistance that accompanies it, and the generation of adhesion force due to surface contact between the bearing surface and the facing surface on the spindle side.

That is, when the spindle is brought into contact with the non-contact bearing in the direction of action of the contact reaction force, the spindle supported by the bearing surface of the non-contact bearing does not move any more, so that the displacement of the spindle due to the contact reaction force is effective. Can be suppressed. When the spindle is brought into contact with the non-contact bearing in the direction intersecting the contact reaction force, the movement of the spindle can be suppressed by increasing the frictional force at the contact point. When the spindle is brought into contact with the non-contact bearing in the direction opposite to the contact reaction force, the spindle can be supported by the generation of the adhesion force between the bearing surface and the facing surface on the spindle side. That is, in general, the bearing surface and the facing surface on the spindle side are smoothed by lap finishing or the like, so that once the bearing surface and the facing surface come into surface contact, they are strongly adhered to each other, and the movement of the spindle can be suppressed. As a result, by performing the measurement with the non-contact bearing switched to the measurement state, the measurement accuracy can be improved even when the contact sensor is attached to the spindle to measure the workpiece in the spindle device using the non-contact bearing. Can be improved.

In the spindle device according to the first aspect, preferably, the non-contact bearing includes an axial bearing portion that supports the spindle from both sides in the axial direction in the axial direction, and a radial bearing portion that supports the spindle in the radial direction. In the state, the axial bearing surface of the axial bearing portion and the axial facing surface of the spindle are configured to come into contact with each other in the axial direction. With this configuration, the axial bearing surface and the axially opposed surface of the spindle can be brought into surface contact in the axial direction. As a result, due to the close contact between the surfaces, the displacement of the spindle can be effectively suppressed against both the axial contact reaction force from the contact sensor and the radial contact reaction force. Further, since the axial position of the spindle is positioned at the contact position with the axial bearing surface of the non-contact bearing, the axial position accuracy of the spindle can be improved. As a result, the workpiece can be measured with higher accuracy.

In this case, preferably, the axial bearing portion includes a one-side axial bearing surface that supports the spindle from one end side and a other-side axial bearing surface that supports the spindle from the other end side opposite to one end side, and is non-contact. In the measured state, the bearing is configured such that the axial bearing surface on one side is separated from the spindle and the axial bearing surface on the other side is in contact with the axial facing surface of the spindle. With this configuration, the axial bearing surface on the other side comes into contact with the axial facing surface of the spindle from the other end side, so that the axial contact reaction force from the contact sensor pushes the spindle in the direction (toward the other end side of the spindle). Even if it acts in the direction), it is possible to surely prevent the spindle from moving. Then, the axial position of the spindle can be positioned at the contact position with the axial bearing surface on the other side. As a result, both prevention of misalignment due to contact reaction force and improvement of axial position accuracy of the spindle in the measured state can be realized.

In a configuration in which the non-contact bearing includes an axial bearing portion and a radial bearing portion, the non-contact bearing is preferably a hydrostatic fluid bearing, further comprising a fluid circuit for controlling pressure supply to the hydrostatic fluid bearing. In the fluid circuit, the supply pressure of one of the one end side and the other end side of the axial bearing portion is weakened or cut off from the other one so that the axial bearing surface and the axial facing surface are brought into contact with each other. It is configured. With this configuration, the axial bearing surface and the axial facing surface can be easily brought into contact with each other simply by adjusting (weakening or shutting off) the supply pressure to the hydrostatic fluid bearing. Further, since it is only necessary to use a fluid circuit for non-contactly supporting the spindle with the hydrostatic fluid bearing, the device configuration is not complicated even when the axial bearing surface and the axially opposed surface are brought into contact with each other.

In this case, preferably, the hydrostatic fluid bearing is a hydrostatic air bearing, and the fluid circuit includes a switching valve that switches between supplying and shutting off air pressure to any one of the axial bearing portions. With such a configuration, it is possible to easily switch to a measurement state in which the axial bearing surface and the axial facing surface are brought into contact with each other with a simple configuration in which a switching valve is provided.

The spindle device according to the first aspect is further provided with an urging portion that brings the spindle into contact with the non-contact bearing by urging the spindle in the axial direction, preferably in the measurement state. With this configuration, the urging unit can easily switch to the measurement state. In addition, when a dedicated urging portion is provided to bring the spindle into contact with the non-contact bearing, the displacement of the spindle can be prevented by setting the urging force according to the magnitude of the contact reaction force from the contact sensor. It can be sufficiently suppressed.

In the spindle device according to the first aspect, preferably, there is no contact between the discriminating unit for determining that the contact sensor is attached to the tool holding portion from the tool changing device and the contact sensor when the contact sensor is attached to the tool holding portion. A control unit that controls switching the bearing to the measurement state is further provided. With this configuration, it is possible to switch to the measurement state when it is determined that the contact sensor is attached to the tool holding portion, whether the measurement is performed before the start of machining by the tool or during the machining. As a result, the user does not need to switch to the measurement state, and the non-contact bearing can be reliably switched to the measurement state at the time of measurement by the contact sensor.

In the spindle device according to the first aspect, preferably, the tool holding portion has a collet member capable of directly holding a straight shank type tool and a contact sensor. With this configuration, unlike the case where a tool with a collet (contact sensor) is attached and detached, it is not necessary to provide a collet chuck for each tool (contact sensor), so that the tool can be miniaturized while reducing the number of parts. Therefore, even when the contact sensor is provided in the tool changing device, the device configuration does not become large.

In the spindle device according to the first aspect, preferably, the drive unit includes an induction motor, and the non-contact bearing is configured to stop the rotation of the spindle by contact with the spindle in the measurement state. Here, when the induction motor is adopted, if the spindle is not driven, the spindle will idle. Therefore, when the contact sensor is attached to the tool holding part, if the central axis of the spindle and the central axis of the contact sensor do not exactly match, the tip of the contact sensor will swing around and the contact position will vary. It becomes a factor that reduces the accuracy. Therefore, according to the above configuration, the work can be measured by the contact sensor while the rotation of the spindle is surely stopped in the measurement state. Therefore, in the configuration in which the induction motor is adopted, special motor control is performed. The measurement accuracy can be easily improved without any problem.

The machine tool according to the second aspect of the present invention has a spindle device according to any one of the first aspects, a moving mechanism for relatively moving the spindle device and the work, and a tool and a contact sensor with respect to the spindle of the spindle device. It is equipped with a tool changing device that is detachably held.

In this machine tool, by configuring as described above, the non-contact bearing is measured when the contact sensor is attached to the tool holding portion and the workpiece is measured, as in the case of the spindle device according to the first aspect. Since the spindle can be supported in the contact state by switching to, when the contact reaction force of the contact sensor acts on the spindle, the spindle due to the contact reaction force is compared with the case where the spindle is held in the non-contact state. Positional deviation can be suppressed. As a result, in a machine tool provided with a spindle device using a non-contact bearing, the measurement accuracy can be improved even when the contact sensor is mounted on the spindle to measure the workpiece.

According to the present invention, in the spindle device using the non-contact bearing as described above, the measurement accuracy can be improved even when the contact sensor is mounted on the spindle to measure the workpiece.

It is a schematic diagram which showed the whole structure of the machine tool provided with the spindle device by 1st Embodiment. It is a schematic vertical sectional view which showed the spindle device by 1st Embodiment. It is a schematic enlarged sectional view of the tool holding part for demonstrating the structure of the tool holding part and tool exchange. It is a schematic diagram of the spindle device for demonstrating the processing state. It is a schematic diagram of the spindle device for demonstrating the measurement state. It is a flow chart for demonstrating the flow of the measurement process using a contact sensor. It is a figure (A) which shows the measurement of a reference gauge, and the figure (B) which shows the measurement of a work. It is a schematic vertical sectional view which showed the spindle device by 2nd Embodiment. It is a schematic diagram of the spindle device for demonstrating the measurement state in 2nd Embodiment. It is a schematic diagram which showed the 1st modification of the tool holding part. It is a schematic diagram which showed the holding state (A) and release state (B) of the 2nd deformation of a tool holding part. It is a schematic diagram which showed the modification of the measurement state shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
The machine tool 200 provided with the spindle device 100 and the spindle device 100 according to the first embodiment will be described with reference to FIGS. 1 to 5.

(Overview of spindle equipment and machine tools)
As shown in FIG. 1, the spindle device 100 rotates the spindle 10 (see FIG. 2) around the central axis to rotate the tool 1 mounted on one end of the spindle 10, and is used as a workpiece. This is a device for processing a certain work 3. The spindle device 100 is assembled to the machine tool 200 and is moved relative to the work 3 by the moving mechanism 110 included in the machine tool 200. The machine tool 200 is a numerically controlled (NC) machine tool, controls the relative motion (position and speed) between the tool 1 and the work 3 by numerical information, and executes a series of operations related to machining by the program 132. Specifically, the machine tool 200 is a machining center provided with a spindle device 100 and a tool changing device 120, and various machining such as drilling, hollowing, and milling can be performed by replacing the tool 1 with respect to the spindle device 100. ..

In the first embodiment, as an example, an example in which the work 3 is a mold for an optical lens and the machine tool 200 performs precision machining of the mold will be described. Since the spindle device 100 and the machine tool 200 of the first embodiment can measure the work 3 with high accuracy by the contact sensor 2, they are particularly suitable for performing precision machining such as manufacturing a mold, which requires high accuracy. Is.

The machine tool 200 includes a spindle device 100, a moving mechanism 110, and a tool changing device 120. Further, the machine tool 200 (spindle device 100) includes a control unit 130 that controls each of these units.

The moving mechanism 110 is configured to move the spindle device 100 and the work 3 relative to each other. The machine tool 200 relatively moves the spindle device 100 and the work 3 in three orthogonal axial directions, at least in the vertical direction and in two directions orthogonal to each other in the horizontal plane. In the relative movement between the spindle device 100 and the work 3, only one of the spindle device 100 and the work 3 may move, or both the spindle device 100 and the work 3 may move. In the example of FIG. 1, the moving mechanism 110 moves the spindle device 100 in the vertical Z direction and the X direction in the horizontal plane (horizontal direction in FIG. 1), and moves the work 3 in the X direction in the horizontal plane. Move in the orthogonal Y directions (front and back directions perpendicular to the paper surface of FIG. 1).

FIG. 1 shows an example in which the machine tool 200 is a portal machining center. The machine tool 200 includes a table 140 on which the work 3 is installed, and a bed 141 that movably supports the table 140 in the Y direction. The machine tool 200 includes a pair of columns 142 arranged on both sides of the bed 141 in the X direction, and a crossbar 143 spanned over the upper ends of the pair of columns 142. The crossbar 143 extends in the X direction so as to straddle the upper part of the table 140 and the bed 141. The crossbar 143 supports the saddle 144 so as to be movable in the X direction. The saddle 144 movably supports the head 145 provided with the spindle device 100 in the Z direction.

The moving mechanism 110 includes a Z-axis moving mechanism 111 that moves the head 145 in the Z direction, an X-axis moving mechanism 112 that moves the saddle 144 in the X direction, and a Y-axis moving mechanism 113 that moves the table 140 in the Y direction. To be equipped. Each of the Z-axis moving mechanism 111, the X-axis moving mechanism 112, and the Y-axis moving mechanism 113 includes, for example, a servomotor 114 having a built-in position detector and a linear motion mechanism (not shown) driven by the servomotor 114. .. The moving mechanism 110 may have more moving axes than the three axes. For example, the moving mechanism 110 rotates the head 145 around the axis in the Y direction (tilts the tool 1 of the spindle device 100 with respect to the horizontal plane) and the table 140 around the Z axis (work). 3 may be provided with a rotation axis (rotating 3 in a horizontal plane).

The tool changing device 120 has a function of holding a plurality of types of tools 1 so that they can be taken out and replacing the tool 1 mounted on the spindle 10 of the spindle device 100. In the first embodiment, the tool changer 120 holds the contact sensor 2 in addition to the tool 1 so that it can be taken out. That is, the tool changing device 120 is configured to detachably hold the tool 1 and the contact sensor 2 with respect to the spindle 10 of the spindle device 100.

The tool changer 120 shown in FIG. 1 includes a magazine 121 that holds the tool 1 and the contact sensor 2, and a motor 122 that drives the magazine 121. The magazine 121 is formed in a disk shape, and has a plurality of holding holes (not shown) along the circumferential direction on the outer peripheral portion. The magazine 121 can hold the tool 1 or the contact sensor 2 in each holding hole in a state in which the tool 1 or the contact sensor 2 can be pulled out upward. The motor 122 is configured to rotate the magazine 121 around a central rotation axis.

The rotation of the magazine 121 allows the desired holding hole of the magazine 121 to be positioned at the tool change position with respect to the spindle device 100. As a result, the machine tool 200 moves the spindle device 100 to the tool changing position above the magazine 121, removes the tool 1 or the contact sensor 2 mounted on the spindle device 100, and sets it in the holding hole of the tool changing position. It is also possible to attach the tool 1 or the contact sensor 2 held in the holding hole moved to the tool changing position to the spindle device 100.

The control unit 130 is configured to control the overall operation of the machine tool 200. The control unit 130 is composed of a processor such as a CPU. The control unit 130 includes a storage unit 131 in which various programs 132 for controlling the machine tool 200 including the machining program of the work 3 are stored. When the processor executes the program stored in the storage unit 131, the processor operates as the control unit 130 of the machine tool 200. As a result, the control unit 130 controls the operation of the spindle device 100, the operation control of the moving mechanism 110, and the operation control of the tool changing device 120. The control unit 130 is provided on, for example, the control panel of the machine tool 200, and is connected to a display unit (not shown) or an input unit (not shown) of the control panel.

(Spindle device)
As shown in FIG. 2, the spindle device 100 includes a spindle 10, a non-contact bearing 20, a drive unit 30, and a tool holding unit 40. The spindle device 100 is packaged as an assembly in which each of these parts is housed in the housing 50.

The main shaft 10 is a shaft member provided at the center of a substantially cylindrical housing 50 so as to extend vertically. The spindle 10 may be a solid shaft member, but in the example of FIG. 2, it has a hollow (see FIG. 3) cylindrical shape. The spindle 10 is rotationally driven around the central axis by the drive unit 30, and rotates the tool 1 mounted on the tool holding portion 40 provided at one end (spindle end) of the spindle 10. In the following, for convenience, the side of the spindle 10 where the tool holding portion 40 is arranged is defined as one end side (Z1 direction), and the side of the spindle 10 opposite to the tool holding portion 40 is defined as the other end side (Z2 direction).

The main shaft 10 is provided with a flange portion 11 protruding outward in the radial direction on the outer peripheral surface. The collar portion 11 has a certain thickness and is formed in a disk shape. In the flange portion 11, axial facing surfaces 11a facing the non-contact bearing 20 in the axial direction are formed on the surfaces of one end side (Z1 direction side) and the other end side (Z2 direction side) in the axial direction. The main shaft 10 is provided with a shaft portion 12 having a constant outer diameter. The shaft portion 12 is provided with a radial facing surface 12a that faces the non-contact bearing 20 in the radial direction. The position of the flange portion 11 is particularly limited, and the collar portion 11 may be arranged on one end side (Z1 direction side) with respect to the shaft portion 12.

The tool holding portion 40 is provided at one end of the spindle 10 and is configured to detachably hold the tool 1 for machining the work 3 or the contact sensor 2 for measuring the work 3. The tool holding portion 40 holds the tool 1 or the contact sensor 2 by engaging with the inserted tool 1 or the contact sensor 2 at one end of the hollow spindle 10. Details of the tool holding portion 40 will be described later.

The non-contact bearing 20 is configured to rotatably support the spindle 10 around the central axis in a non-contact manner. The non-contact bearing 20 is configured to rotatably support the spindle 10 around the central axis in a non-contact manner at least when the spindle 10 is rotationally driven. In other words, the non-contact bearing 20 is configured to be in a machined state P1 (see FIG. 4) that rotatably supports the spindle 10 in a non-contact state when the tool 1 is mounted. Then, in the first embodiment, the non-contact bearing 20 can be switched to the measurement state P2 (see FIG. 5) in which the movement of the spindle 10 is suppressed by supporting the spindle 10 in a contact state when the contact sensor 2 is mounted. It is configured. As the non-contact bearing 20, a hydrostatic fluid bearing using oil or air as a working fluid or a magnetic bearing can be adopted. In the first embodiment, the non-contact bearing 20 is a hydrostatic fluid bearing, and is particularly composed of a hydrostatic air bearing. The hydrostatic air bearing is a bearing that introduces a pressurized gas into the gap CL between the bearing and the spindle and non-contactly supports the load (own weight and contact reaction force) acting on the spindle 10 due to the balance of gas pressure. ..

The non-contact bearing 20 includes an axial bearing portion 21 that supports the spindle 10 from both sides in the axial direction, and a radial bearing portion 22 that supports the spindle 10 in the radial direction.

The axial bearing portion 21 has a pair of axial bearing surfaces arranged on both sides in the axial direction with respect to the flange portion 11 of the main shaft 10. That is, the axial bearing portion 21 includes a one-side axial bearing surface 21a that supports the spindle 10 from one end side and a other-side axial bearing surface 21b that supports the spindle 10 from the other end side. The one-side axial bearing surface 21a and the other-side axial bearing surface 21b are both examples of the "axial bearing surface" within the scope of the claims. The one-side axial bearing surface 21a and the other-side axial bearing surface 21b are formed in an annular shape in the axial direction, respectively, and face each other in the axial direction with a minute gap CL from the axial facing surface 11a of the flange portion 11. It is provided. Compressed air is supplied to the axial bearing portion 21 from the pneumatic source (positive pressure source) 60 via the fluid circuit 70 described later and the passage portion 51 of the housing 50. The one-side axial bearing surface 21a and the other-side axial bearing surface 21b are each provided with aperture holes (not shown) for discharging compressed air in the gap CL between the axial bearing surface 11a and the axial bearing surface 11a. As a result, the axial bearing portion 21 has the shaft of the spindle 10 due to the balance of the pressures of the working fluids (air) supplied from the axial bearing surface 21a on one side and the axial bearing surface 21b on the other side to both sides of the flange portion 11 in the axial direction. It is possible to support the direction (axial direction) in a non-contact manner.

The radial bearing portion 22 has a radial bearing surface 22a formed concentrically with respect to the shaft portion 12 of the main shaft 10. The radial bearing surface 22a is provided so as to face the radial facing surface 12a of the main shaft 10 with a minute gap CL. Compressed air is supplied to the radial bearing portion 22 via the passage portion 51. The radial bearing surface 22a is provided with a throttle hole (not shown) for discharging compressed air in the gap CL with the radial facing surface 12a. As a result, the radial bearing portion 22 is supported in the radial direction (radial direction) of the main shaft 10 by the balance of the pressure of the working fluid (air) supplied to the gap CL between the radial bearing surface 22a and the radial facing surface 12a. Can be done non-contact.

Two radial bearing portions 22 are provided at positions separated from each other along the axial direction of the main shaft 10. This prevents the spindle 10 from tilting. The radial bearing portion 22 on the other end side in the axial direction is provided on a bearing body having an L-shaped cross section common to the axial bearing portion 21.

In order to suppress pressure fluctuations and pressure fluctuations during rotational drive of the spindle 10, these bearing surfaces (one-side axial bearing surface 21a, the other-side axial bearing surface 21b, radial bearing surface 22a) and the facing surface (axial) of the spindle 10 The facing surface 11a and the radial facing surface 12a) are formed of a lap-finished surface. That is, these bearing surfaces and facing surfaces are each formed with extremely small surface roughness and high dimensional accuracy. The size of the gap CL between the axial bearing portion 21 and the radial bearing portion 22 with the spindle 10 is, for example, about 8 μm or more and 20 μm or less. The size of the gap CL between the axial bearing portion 21 and the spindle 10 and the size of the gap CL between the radial bearing portion 22 and the spindle 10 may be different.

The spindle device 100 includes a fluid circuit 70 that controls the pressure supply to the non-contact bearing 20 which is a hydrostatic fluid bearing. The fluid circuit 70 communicates with the non-contact bearing 20 and is connected to an external pneumatic source 60 via a pressure regulating valve 71 (see FIG. 4). As a result, compressed air of a predetermined pressure is supplied to the non-contact bearing 20 via the fluid circuit 70. The air pressure to be supplied is, for example, about 0.3 MPa or more and about 0.7 MPa or less.

The drive unit 30 is configured to rotationally drive the spindle 10. The drive unit 30 is connected to the other end of the main shaft 10 and is configured to directly rotate and drive the main shaft 10 around the central axis. The drive unit 30 is an electric motor capable of rotating at a high speed of about 60,000 rpm, and is a built-in motor incorporated inside the housing 50. As the motor, a synchronous motor, an induction motor, or the like can be adopted, but in the first embodiment, the drive unit 30 is composed of an induction motor. The induction motor generates an induced current in the rotor 32 by the rotating magnetic field generated in the stator 31, and rotates the rotor 32 by the interaction between the magnetic field generated by the induced current and the rotating magnetic field of the stator 31. The rotor 32 is fixed to the spindle 10. The stator 31 is fixed to the housing 50 so as to surround the radial outer side of the rotor 32.

In the example of FIG. 2, the spindle device 100 includes a switching mechanism 80 for switching between chucking (grasping) and releasing (grasping release) of the tool 1 by the tool holding portion 40. The switching mechanism 80 is a push rod that is inserted into the actuator 81 provided on the other end side (Z2 direction side) of the spindle 10 and the hollow spindle 10 and extends from the other end side to the vicinity of the tool holding portion 40. Includes 82 and. The actuator 81 is composed of, for example, a pneumatic or hydraulic piston, an electric solenoid, or the like, and advances and retracts the push rod 82 in the axial direction.

(Replacement of tools)
In the configuration example of the first embodiment shown in FIG. 3, the tool holding portion 40 is configured to be able to directly grip the shank portion 1a (2a) of the tool 1 or the contact sensor 2 and hold the tool 1 or the contact sensor 2. ing. That is, the tool holding portion 40 has a collet member 41 capable of directly holding the straight shank type tool 1 and the contact sensor 2.

Specifically, the tool holding portion 40 includes a collet member 41, a hollow cylindrical sleeve 42 fixed to one end of a spindle 10, a disc spring 43, and a collet nut 44. One end side of the sleeve 42 is a chuck hole formed in a tapered shape so that the inner diameter becomes smaller toward the other end side (Z2 direction side), and the collet member 41 is inserted. The collet member 41 has a tubular shape capable of holding the shank portion 1a (2a) on the inner peripheral side, and is inserted into the sleeve 42 from one end side (Z1 direction side) of the sleeve 42. The one end side portion of the collet member 41 is formed in a tapered shape so as to correspond to the chuck hole of the sleeve 42 and the outer diameter becomes smaller toward the other end portion.

The collet member 41 is formed with a notch 41a extending in the axial direction from an intermediate position to one end. The collet member 41 penetrates the sleeve 42 and extends to the other end side, and a collet nut 44 is provided at the other end of the collet member 41. Then, the collet member 41 is urged toward the other end side (Z2 direction side) by the disc spring 43 provided between the sleeve 42 and the collet nut 44. As a result of the collet member 41 being urged to the inner side (Z2 direction side) of the tapered chuck hole of the sleeve 42 by the disc spring 43, one end of the collet member 41 (the portion where the notch 41a is formed) is radially. It is compressed and deformed inward to reduce the inner diameter. The tool 1 or the contact sensor 2 is gripped (clamped) by the action of a compressive force in the radial direction on the shank portion 1a (2a) of the tool 1 or the contact sensor 2 inserted into one end of the collet member 41.

When the push rod 82 is advanced toward the tool holding portion 40 by the actuator 81 of the switching mechanism 80, the tip of the push rod 82 comes into contact with the other end of the collet member 41, and the collet member 41 is on one end side (Z1 direction side). Is pressed toward. The switching mechanism 80 compresses the disc spring 43 and pushes the collet member 41 toward one end by a predetermined amount by applying a pressing force larger than the urging force of the disc spring 43. Since the collet member 41 is pushed out from the tapered chuck hole, the compressive force in the radial direction is weakened, so that the gripping force of the shank portion 1a (2a) of the tool 1 or the contact sensor 2 is weakened. As a result, the holding of the tool 1 or the contact sensor 2 can be released (released) by the operation of the actuator 81.

The tool 1 and the contact sensor 2 are held in the magazine 121 of the tool changing device 120 in a posture in which the shank portion 1a (2a) is directed upward (Z1 direction). At the time of tool change, the machine tool 200 moves the spindle device 100 above the holding hole at the tool change position under the control of the control unit 130, and moves the shank portion 1a (2a) to the collet member 41 with the push rod 82 advanced. Insert it inside. Then, the machine tool 200 causes the collet member 41 to grip the shank portion 1a (2a) of the tool 1 or the contact sensor 2 by retracting the push rod 82. As a result, the tool 1 or the contact sensor 2 is held by the tool holding portion 40. When returning the tool 1 or the contact sensor 2 to the tool changing device 120, the machine tool 200 advances the push rod 82 in the tool changing position with the tool 1 or the contact sensor 2 placed in the original holding hole to move the tool. The grip by the holding portion 40 is released.

In the tool 1, a blade portion 1b for machining the work 3 is formed at one end (Z1 direction side), and a shank portion 1a is provided at the other end (Z2 direction side). The contact sensor 2 has a touch probe 2b at one end, and a shank 2a is provided at the other end of the contact sensor 2. The contact sensor 2 detects the contact of the touch probe 2b with the object to be measured. The contact sensor 2 has, for example, a built-in strain gauge, and detects contact based on the strain caused by the stress generated by the contact between the touch probe 2b and the object to be measured. The contact sensor 2 has a built-in wireless communication unit and outputs a detection signal to a reception unit (not shown) arranged at a predetermined position in the machine tool 200. Based on the output of the contact sensor 2, the contact position between the touch probe 2b and the object to be measured can be accurately measured.

(Processing state and measurement state)
Next, a machining state in which the tool 1 is attached to the spindle device 100 for machining and a measurement state in which the contact sensor 2 is attached to the spindle device 100 to measure the work 3 will be described.

As described above, in the first embodiment, when the tool 1 is mounted, the non-contact bearing 20 is in a processed state P1 (see FIG. 4) that rotatably supports the spindle 10 in a non-contact state, and the contact sensor 2 is mounted. At times, it is possible to switch to the measurement state P2 (see FIG. 5) in which the movement of the spindle 10 is suppressed by supporting the spindle 10 in a contact state.

<Processing state>
First, in the processed state P1, as shown in FIG. 4, the compressed air from the pneumatic source 60 is brought into the axial bearing surface 21a on one side and the axial bearing surface 21b on the other side by the fluid circuit 70. Supplied to both. As a result, the spindle 10 is supported in the axial direction in a non-contact state with respect to the axial bearing portion 21. Further, in the processing state P1, compressed air from the pneumatic source 60 is supplied to each radial bearing surface 22a of the two radial bearing portions 22. As a result, the spindle 10 is supported in the radial direction in a non-contact state with respect to the radial bearing portion 22. As a result, the spindle 10 has a central shaft in a state in which movement in the axial direction (Z direction) and the radial direction (XY direction) is restrained in a non-contact manner by the air pressure supplied to the gap CL with the non-contact bearing 20. It is supported so that it can rotate around.

In this state, the spindle 10 is rotationally driven by the drive unit 30, and the tool 1 mounted on the spindle 10 is rotated at high speed. Then, the spindle device 100 and the work 3 are relatively moved by the moving mechanism 110, and the tool 1 is brought into contact with the work 3 to perform cutting.

<Measurement state>
On the other hand, as shown in FIG. 5, in the non-contact bearing 20, in the measurement state P2, the axial bearing surface (the other side axial bearing surface 21b) of the axial bearing portion 21 and the axial facing surface 11a of the spindle 10 are in the axial direction. It is configured to come into contact with.

That is, the supply pressure to the non-contact bearing 20 is adjusted so that the spindle 10 and the non-contact bearing 20 come into contact with each other. In the measurement state P2, the fluid circuit 70 weakens or cuts off the supply pressure of one of the one end side (Z1 direction side) and the other end side (Z2 direction side) of the axial bearing portion 21 than the other one. By doing so, the axial bearing surface and the axial facing surface 11a are made to come into contact with each other.

More specifically, in the first embodiment, the fluid circuit 70 includes a switching valve 72 that switches between supplying (on) and shutting off (off) air pressure to any one of the axial bearings 21. That is, in the measurement state P2, the switching valve 72 cuts off the supply of air pressure to any one of the axial bearing portions 21, so that the spindle 10 moves to the cut off side, and the axial bearing surface and the axial facing surface 11a Come in contact with.

The fluid circuit 70 is separately provided with a flow path 73 communicating with the throttle hole of the one-side axial bearing surface 21a and a flow path 74 communicating with the throttle hole of the other-side axial bearing surface 21b. The switching valve 72 is arranged on the flow path 74 communicating with the throttle hole of the axial bearing surface 21b on the other side. Therefore, the switching valve 72 can switch between supplying and shutting off the compressed air to the one-side axial bearing surface 21b while continuing to supply the compressed air to the one-side axial bearing surface 21a. By cutting off the supply of compressed air to the other side axial bearing surface 21b, only the portion of the gap CL between the one side axial bearing surface 21a and the other side axial bearing surface 21a becomes high pressure, and the spindle 10 moves to the other side axial bearing surface 21b side. ..

With such a configuration, in the first embodiment shown in FIG. 5, in the non-contact bearing 20, one side axial bearing surface 21a is separated from the main shaft 10 and the other side axial bearing surface 21b is the main shaft 10 in the measurement state P2. It is configured to come into contact with the axial facing surface 11a. The spindle 10 moves in the other end side (Z2 direction) in the axial direction by the size of the gap CL (about 8 μm to about 20 μm) between the axial bearing surface 21b on the other side and the axial facing surface 11a. As a result, the other side axial bearing surface 21b and the axial facing surface 11a come into surface contact with each other.

In the measurement state P2, since the axial facing surface 11a of the spindle 10 comes into contact with the other axial bearing surface 21b, the axial (Z direction) position of the spindle 10 is aligned with the other axial bearing surface 21b and the axial facing surface 11a. It is accurately positioned by the contact position of. Further, the external force of the spindle 10 toward the other end side in the axial direction (Z2 direction) is supported by the axial bearing portion 21, and the movement of the spindle 10 is restricted so that the spindle 10 cannot move further to the other end side.

Here, unlike a synchronous motor in which a permanent magnet is provided in the rotor, the induction motor is provided with only a conductor, so that the rotor 32 (main shaft 10) is in a free rotation state when the motor is not driven. On the other hand, as described above, since the bearing surface of the non-contact bearing 20 and the facing surface of the spindle 10 are each smoothed by lap finishing, they are axially opposed to the other side axial bearing surface 21b in the surface contact state. Strongly adheres to the surface 11a. Therefore, in the measurement state P2, the rotation of the spindle 10 is stopped. As described above, the non-contact bearing 20 is configured to stop the rotation of the spindle 10 by contact with the spindle 10 in the measurement state P2. Similarly, in the measurement state P2, the movement of the spindle 10 in the radial direction is suppressed by the close contact between the axial bearing surface 21b on the other side and the axial facing surface 11a.

In this state, the spindle device 100 and the work 3 are relatively moved by the moving mechanism 110, and by bringing the contact sensor 2 into contact with the object to be measured such as the work 3, the dimensions of the object to be measured and the coordinate system of the moving mechanism 110 Precise measurement of the contact position is performed.

As the measurement by the contact sensor 2, for example, the outer shape and position of the work 3 (see FIG. 7) are measured, and the shape of the surface to be machined is measured. For example, the outer shape of the rectangular parallelepiped work 3 is measured by contact with four horizontal surfaces in the horizontal direction (radial direction of the spindle 10) and contact with the upper surface in the vertical direction (axial direction of the spindle 10). For example, the shape of the work surface formed on the upper surface of the work 3 is obtained by making contact with a plurality of measurement points in the surface of the work surface in the vertical direction (axial direction of the spindle 10). It is measured by approximating the distribution of three-dimensional positions of points to obtain the shape of the surface to be machined.

Therefore, especially when the contact sensor 2 is brought into contact with the object to be measured from above in the axial direction (Z direction), it is moved to the other end side (Z2 direction) in the axial direction due to the contact between the contact sensor 2 and the object to be measured. The oncoming contact reaction force FR (see FIG. 5) acts on the spindle 10. Due to the structure of the contact sensor 2, the pressing force against the object to be measured is about 0.1 N to 1 N in the horizontal direction, whereas it is as large as about 1 N to about 7 N in the axial direction. In the first embodiment, by bringing the other side axial bearing surface 21b and the axially opposed surface 11a into contact with each other in the measurement state P2, the contact reaction force FR in the axial direction is supported and the displacement of the spindle 10 is prevented. In the horizontal measurement, since the pressing force is small, the positional deviation in the radial direction is sufficiently prevented by the close contact between the axial bearing surface 21b on the other side and the axial facing surface 11a.

When returning to the processed state P1 after switching to the measurement state P2, the other side axial bearing is switched by switching the switching valve 72 so as to supply compressed air to the other side axial bearing surface 21b as shown in FIG. The contact between the surface 21b and the axially opposed surface 11a can be released to switch to the machining state P1.

Switching between the machining state P1 and the measurement state P2 is controlled by the control unit 130 depending on whether the attachment mounted on the spindle 10 is the tool 1 or the contact sensor 2. That is, in the first embodiment, the spindle device 100 includes a discriminating unit 133 that determines from the tool changing device 120 that the contact sensor 2 is mounted on the tool holding unit 40. Then, the control unit 130 is configured to control the non-contact bearing 20 to be switched to the measurement state P2 when the contact sensor 2 is mounted on the tool holding unit 40.

When the control unit 130 controls to execute a series of machining operations according to the program 132 that defines the machining operation by the machine tool 200, the discrimination unit 133 is equipped with the tool 1 or the contact sensor 2. Determine if. When the determination unit 133 determines that the contact sensor 2 is mounted, the control unit 130 controls the switching valve 72 of the fluid circuit 70 to shut off the compressed air to the other side axial bearing surface 21b. When the determination unit 133 determines that the tool 1 is attached, the control unit 130 controls the switching valve 72 of the fluid circuit 70 to supply compressed air to the other side axial bearing surface 21b.

In the first embodiment, the discrimination unit 133 is configured as one of the functional blocks by the control unit 130 executing the control program, and is realized by software. A processor separate from the control unit 130 may be provided, and the determination unit 133 may be configured by hardware.

<Measurement operation control>
Next, with reference to FIG. 6, the measurement operation control will be described using the contact sensor 2. Here, an example in which the position and shape of the work 3 are measured when the work 3 is machined by the machine tool 200 will be described.

In step S1, the control unit 130 attaches the contact sensor 2 to the tool holding unit 40 according to the program 132.

In step S2, the determination unit 133 determines whether or not the contact sensor 2 is attached to the tool holding unit 40 of the spindle 10. If the contact sensor 2 is not attached, the measurement operation is not started.

When the contact sensor 2 is attached, the control unit 130 proceeds to step S3 and switches the non-contact bearing 20 to the measurement state P2. That is, the switching valve 72 is switched to shut off the supply of compressed air to the throttle hole of the axial bearing surface 21b on the other side. As a result, the non-contact bearing 20 and the spindle 10 come into contact with each other, and the movement of the spindle 10 is suppressed.

Next, in steps S4 and S5, the control unit 130 executes zero point adjustment (calibration) by measuring the reference gauge 4 using the contact sensor 2.

As shown in FIG. 1, the reference gauge 4 is arranged on, for example, a table 140 on which the work 3 is installed. In FIG. 1, for convenience of illustration, the reference gauge 4 is shown at a position arranged in the X direction with respect to the work 3, but for example, the reference gauge 4 may be arranged at a position arranged in the Y direction with respect to the work 3. ..

The reference gauge 4 shown in FIG. 7A is a jig manufactured in advance with high dimensional accuracy by using ceramic or the like, and has, for example, an annular shape. The control unit 130 controls the moving mechanism 110 in the measurement state P2 to bring the touch probe 2b of the contact sensor 2 into contact with a plurality of locations on the inner peripheral surface of the reference gauge 4, and the control unit 130 contacts the reference position in the horizontal plane (in the XY plane). Get the coordinates. Further, the control unit 130 brings the touch probe 2b of the contact sensor 2 into contact with the upper surface of the reference gauge 4 to acquire the reference position coordinates in the Z direction.

In step S5, the control unit 130 sets zero points in the horizontal direction (XY direction) and the vertical direction (Z direction) based on the acquired reference position coordinates of the reference gauge 4. This zero point serves as a reference position for measuring the position and shape of the work 3.

In step S6, the control unit 130 measures the position and shape of the work 3 using the contact sensor 2. The control unit 130 controls the moving mechanism 110 in the measurement state P2 to bring the touch probe 2b of the contact sensor 2 into contact with each outer surface (4 side surfaces) of the work 3 as shown in FIG. 7B. , Measure the horizontal position of the work 3 on each side surface. Further, the control unit 130 brings the touch probe 2b of the contact sensor 2 into contact with the upper surface of the work 3 and measures the height position (position in the Z direction) of the upper surface of the work 3. Further, the control unit 130 brings the touch probe 2b of the contact sensor 2 into contact with a plurality of measurement points set on the work surface of the work 3 to measure the shape of the work surface. As a result, the position and shape of the work 3 are precisely measured with reference to the zero point set by the reference gauge 4.

After the measurement is completed, the control unit 130 determines in step S7 whether or not to perform correction processing. For example, in FIG. 7B, when it is confirmed from the measurement result that the processed work 3 is formed in a desired shape, the control unit 130 ends the measurement process because the correction process is unnecessary. .. If the work 3 is not formed in a desired shape, the control unit 130 advances the process to step S8.

In step S8, the control unit 130 mounts the tool 1 from the tool changer 120 on the tool holding unit 40 instead of the contact sensor 2. In step S9, the discriminating unit 133 determines whether or not the tool 1 is mounted on the tool holding unit 40 of the spindle 10. If the tool 1 is not attached, the machining operation is not started.

When the tool 1 is attached, the control unit 130 switches the non-contact bearing 20 from the measurement state P2 to the machining state P1 in step S10. That is, the switching valve 72 is switched to supply compressed air to the throttle hole of the axial bearing surface 21b on the other side. As a result, the non-contact bearing 20 and the spindle 10 are separated from each other, and the spindle 10 is rotatably supported in a non-contact state.

After that, the control unit 130 executes machining operation control according to the control program. That is, the control unit 130 causes the drive unit 30 to rotate the spindle 10 at high speed, and causes the work 3 to be machined based on the position information and the shape information obtained by the measurement.

The measurement of the work 3 can be performed at a predetermined timing during processing. The timing at which the measurement of the work 3 is performed is determined by the program 132 that defines the machining operation. Therefore, when the contact sensor 2 is attached to the spindle 10 (step S1) in order to measure the work 3 during machining, the work 3 is measured by performing the steps S2 to S6. When measuring the position and shape of the unprocessed work 3 before machining the work 3, steps S1 to S6 are performed to measure the position and shape of the work 3, and steps S8 to S10 are performed to perform the tool. After exchanging, the machining of the work 3 is started based on the measurement result.

(Effect of the first embodiment)
In the first embodiment, the following effects can be obtained.

In the first embodiment, as described above, the non-contact bearing 20 is configured to be switchable to the measurement state P2 in which the movement of the spindle 10 is suppressed by supporting the spindle 10 in a contact state when the contact sensor 2 is mounted. As a result, when the contact sensor 2 is attached to the tool holding portion 40 to measure the work 3, the non-contact bearing 20 is switched to the measurement state P2, and the non-contact bearing 20 supports the spindle 10 in the contact state. Can be done. Therefore, when the contact reaction force FR of the contact sensor 2 acts on the spindle 10, the displacement of the spindle 10 due to the contact reaction force FR can be suppressed as compared with the case where the spindle 10 is held in the non-contact state. ..

Specifically, for example, in the spindle device 100 that rotates at a high speed of about 60,000 rpm, the rigidity of the hydrostatic air bearing is usually about 10 N / μm to about 20 N / μm in the axial direction (axial direction). NS. On the other hand, when the touch probe 2b is pressed against the object to be measured in the axial direction, the pressing pressure is about 1N to about 7N as described above. When the rigidity is 10 N / μm and the pressing force is 7 N, the spindle 10 is displaced by 0.7 μm, which makes it difficult to perform precise measurement with the accuracy required for the mold. On the other hand, according to the configuration of the first embodiment, the spindle 10 is mechanically brought into contact with the non-contact bearing 20 in the direction of action of the contact reaction force FR, so that the displacement of the spindle 10 is effectively performed. Can be suppressed. As a result, by performing the measurement in the state where the non-contact bearing 20 is switched to the measurement state P2, the contact sensor 2 is mounted on the spindle 10 and the work 3 is measured in the spindle device 100 that employs the non-contact bearing 20. Even in this case, the measurement accuracy can be improved.

Further, in the first embodiment, as described above, in the measurement state P2, the axial bearing surface (the other side axial bearing surface 21b) of the axial bearing portion 21 and the axial facing surface 11a of the main shaft 10 come into axial contact with each other. As described above, since the non-contact bearing 20 is formed, the axial bearing surface (the other side axial bearing surface 21b) and the axial facing surface 11a of the main shaft 10 can be brought into surface contact in the axial direction. As a result, the displacement of the spindle 10 can be effectively suppressed against both the axial contact reaction force FR and the radial contact reaction force from the contact sensor 2 due to the close contact between the surfaces. Further, since the axial position of the spindle 10 is positioned at the contact position with the axial bearing surface of the non-contact bearing 20, the axial position accuracy of the spindle 10 can be improved. As a result, the work 3 can be measured with higher accuracy.

Further, in the first embodiment, as described above, in the measurement state P2, the one-side axial bearing surface 21a is separated from the spindle 10, and the other-side axial bearing surface 21b is in contact with the axial facing surface 11a of the spindle 10. It constitutes a non-contact bearing 20. As a result, the other side axial bearing surface 21b on the other end side (Z2 direction side) comes into contact with the axial facing surface 11a of the main shaft 10, so that the axial contact reaction force FR (see FIG. 5) from the contact sensor 2 is the main shaft. Even when the action is applied in the direction of pushing the 10 (Z2 direction), it is possible to reliably prevent the spindle 10 from moving. Then, the axial position of the spindle 10 can be positioned at the contact position with the axial bearing surface 21b on the other side. As a result, it is possible to both prevent the positional deviation due to the contact reaction force FR and improve the positional accuracy of the spindle 10 in the axial direction in the measurement state P2.

Further, in the first embodiment, as described above, the fluid circuit 70 cuts off the supply pressure of either one side (the other side) of the axial bearing portion 21 and the other side, so that the axial bearing surface is cut off. (The other side axial bearing surface 21b) and the axial facing surface 11a are configured to be in contact with each other. As a result, the axial bearing surface and the axial facing surface 11a can be easily brought into contact with each other simply by adjusting (cutting off) the supply pressure to the hydrostatic fluid bearing. Further, since it is only necessary to use the fluid circuit 70 for non-contactly supporting the spindle 10 by the hydrostatic fluid bearing, the device configuration may be complicated even when the axial bearing surface and the axial facing surface 11a are brought into contact with each other. No. Instead of shutting off the supply pressure to the other side, the supply pressure to the other side may be weaker than the supply pressure to the one side. If the supply pressure to the other side is made sufficiently smaller than the supply pressure to the one side, the axial bearing surface and the axial facing surface 11a can be brought into contact with each other due to the pressure difference. Therefore, if the axial bearing surface and the axial facing surface 11a can be brought into contact with each other, it is not necessary to completely shut off the supply pressure to the other side.

Further, in the first embodiment, as described above, the fluid circuit 70 is provided with a switching valve 72 for switching between supplying and shutting off air pressure to any one of the axial bearing portions 21. As a result, it is possible to easily switch to the measurement state P2 in which the axial bearing surface and the axial facing surface 11a are brought into contact with each other with a simple configuration in which the switching valve 72 is provided.

Further, in the first embodiment, as described above, the determination unit 133 for determining that the contact sensor 2 is attached to the tool holding unit 40 from the tool changing device 120 and the contact sensor 2 are attached to the tool holding unit 40. In this case, a control unit 130 that controls switching the non-contact bearing 20 to the measurement state P2 is provided. As a result, it is possible to switch to the measurement state P2 when it is determined that the contact sensor 2 is attached to the tool holding portion 40, whether the measurement is performed before the start of machining by the tool 1 or during the machining. As a result, the user does not need to switch to the measurement state P2, and the non-contact bearing 20 can be reliably switched to the measurement state P2 at the time of measurement by the contact sensor 2.

Further, in the first embodiment, as described above, the tool holding portion 40 is provided with a collet member 41 capable of directly holding the straight shank type tool 1 and the contact sensor 2. As a result, unlike the case where the tool 1 with a collet (contact sensor 2) is attached and detached, it is not necessary to provide a collet chuck for each tool 1 (contact sensor 2), so that the tool 1 can be miniaturized while reducing the number of parts. .. Therefore, even when the contact sensor 2 is provided in the tool 1 changing device, the device configuration does not become large.

Further, in the first embodiment, as described above, the drive unit 30 is configured by the induction motor, and the non-contact bearing 20 is configured to stop the rotation of the spindle 10 by contact with the spindle 10 in the measurement state P2. do. As described above, when the induction motor is adopted and the spindle 10 is not driven, the spindle 10 idles. Therefore, when the contact sensor 2 is attached to the tool holding portion 40, if the central axis of the spindle 10 and the central axis of the contact sensor 2 do not exactly match, the tip of the contact sensor 2 swings around and the work 3 And the contact position with the reference gauge 4 varies, which causes a decrease in measurement accuracy. Therefore, according to the above configuration, the work 3 can be measured by the contact sensor 2 in a state where the rotation of the spindle 10 is surely stopped in the measurement state P2. Therefore, in the configuration in which the induction motor is adopted, a special motor control is performed. The measurement accuracy can be easily improved without performing the above.

Further, in the first embodiment, by configuring the machine tool 200 including the spindle device 100 configured as described above, the contact sensor 2 is used as the spindle in the machine tool 200 including the spindle device 100 that employs the non-contact bearing 20. Even when the work 3 is measured by mounting it on the work 3, the measurement accuracy can be improved.

[Second Embodiment]
Next, the spindle device 101 according to the second embodiment will be described with reference to FIGS. 8 and 9. In the second embodiment, unlike the first embodiment in which the pressure supply to the axial bearing surface 21b on the other side of the axial bearing portion 21 is cut off to switch to the measurement state P2, the spindle 10 is urged in the axial direction. A configuration in which the bearing unit 210 is provided will be described. In the second embodiment, the configurations other than the spindle device 101 are the same as those in the first embodiment, and thus the description thereof will be omitted. Further, in the second embodiment, the same configurations as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 8, in the spindle device 101 of the second embodiment, the spindle 10 and the non-contact bearing 20 are urged in the axial direction (Z direction) in the measurement state P2 (see FIG. 9). An urging portion 210 is provided for contact with.

The urging portion 210 applies an external force to the spindle 10 and presses it against the non-contact bearing 20. As a result, in the measurement state P2 (see FIG. 9), the spindle 10 and the non-contact bearing 20 come into contact with each other. Due to the contact between the spindle 10 and the non-contact bearing 20, even if the contact reaction force FR of the touch probe 2b acts on the spindle 10, the movement of the spindle 10 is suppressed.

The urging portion 210 is not particularly limited as long as it has a configuration capable of applying an external force to the spindle 10. In the example of FIG. 8, the urging portion 210 is arranged on the other end side (Z2 direction side) in the axial direction with respect to the driving portion 30, and is configured to urge the main shaft 10 by air pressure. That is, compressed air is supplied to the urging unit 210 via the fluid circuit 70. The urging portion 210 has an annular supply surface 211 facing the balance ring 33 provided at the other end in the axial direction of the rotor 32 and having a push rod 82 inserted inside. The urging portion 210 is configured to discharge compressed air to the balance ring 33 from a throttle hole (not shown) provided on the supply surface 211.

As shown in FIG. 9, the fluid circuit 70 can switch between supplying pressure to the urging portion 210 and shutting off the pressure by the switching valve 220. As a result, when the switching valve 220 is on (supplied), the balance ring 33, the rotor 32, and the main shaft 10 connected to these are moved to one end side (Z1 direction) in the axial direction by the air pressure supplied from the urging portion 210. Be urged towards. As a result, the non-contact bearing 20 is configured to be switched to the measurement state P2 in which the movement of the spindle 10 is suppressed by supporting the spindle 10 in the contact state when the switching valve 220 is switched to the ON state.

In the off (cut-off) state of the switching valve 220, the urging is released by shutting off the supply of compressed air, and the spindle 10 is rotationally supported by the non-contact bearing 20 in a non-contact state. As a result, the non-contact bearing 20 is configured to be switched to the processed state P1 that rotatably supports the spindle 10 in the non-contact state as shown in FIG. 8 when the switching valve 220 is switched to the off state. ..

As described above, in the example of FIG. 9, the urging portion 210 is configured to bring the one-side axial bearing surface 21a into contact with the axial facing surface 11a by urging the spindle 10 toward one end side (Z1 direction). Has been done.

Therefore, in the case of the second embodiment, in the measurement state P2, the other side axial is on the other end side (Z2 direction side), which is the action direction of the contact reaction force FR in the axial direction with respect to the flange portion 11 of the main shaft 10. A gap is formed between the bearing surface and the bearing surface 21b. Therefore, when the contact reaction force FR is larger than the urging force FF of the urging portion 210, the spindle 10 may be displaced to the other end side.

In that case, the pressure on the other end side of the axial bearing portion 21 increases as the gap CL between the other side axial bearing surface 21b and the axial facing surface 11a decreases, so that the own weight of the spindle 10, the urging force FF, and the other end side It is considered that the displacement of the spindle 10 stops at a position where the resultant force with the pressure FP and the contact reaction force FR are balanced. In such a case, the spindle 10 is positioned in the axial direction at the contact position between the one-side axial bearing surface 21a and the axial facing surface 11a, and the displacement due to the predetermined contact reaction force FR occurs. If the contact reaction force FR acts, the displacement amount becomes the same.

Therefore, when the pressing force by the touch probe 2b is the same when measuring the reference gauge 4 (see FIG. 7 (A)) and when measuring the work 3 (see FIG. 7 (B)), the contact reaction force FR is also the same. Therefore, the amount of displacement of the spindle 10 is also equal. That is, when the reference gauge 4 is measured, the zero point is adjusted with the spindle 10 displaced by a predetermined amount in the axial direction by the contact reaction force FR, and then when the work 3 is measured, the same contact reaction force FR is used. Since the measurement is performed in a state of being displaced by a fixed amount, as a result, the work 3 can be measured without being affected by the axial displacement of the spindle 10.

Therefore, in the second embodiment, the control unit 130 measures the moving mechanism 110 (FIG. 1) so that the contact sensor 2 makes measurements with the same pressing force when measuring the reference gauge 4 and when measuring the work 3. See).

In the second embodiment, the control unit 130 weakens or cuts off the supply pressure to the throttle hole of the axial bearing surface 21a on one side of the axial bearing unit 21 in the measurement state P2. As a result, the one-side axial bearing surface 21a and the axially opposed surface 11a can be brought into close contact with each other, and a close contact force can be generated between the two, so that the movement of the spindle 10 due to the contact reaction force FR can be effectively suppressed.

Further, preferably, the urging portion 210 is configured to urge with an urging force FF larger than the pressing force in the axial direction with respect to the work 3 at the time of measurement of the work 3 by the contact sensor 2. As a result, even if the contact reaction force FR of the touch probe 2b acts on the spindle 10, the movement of the spindle 10 can be reliably suppressed.

Other configurations of the second embodiment are the same as those of the first embodiment.

(Effect of the second embodiment)
In the second embodiment, the following effects can be obtained.

In the second embodiment, as in the first embodiment, the non-contact bearing 20 is switched to the measurement state P2 in which the movement of the spindle 10 is suppressed by supporting the spindle 10 in a contact state when the contact sensor 2 is mounted. By making it possible, when the contact sensor 2 is attached to the tool holding portion 40 and the work 3 is measured, the non-contact bearing 20 is switched to the measurement state P2, and the non-contact bearing 20 brings the spindle 10 into contact state. Can be supported by. Therefore, when the contact reaction force FR of the contact sensor 2 acts on the spindle 10, the displacement of the spindle 10 due to the contact reaction force FR can be suppressed as compared with the case where the spindle 10 is held in the non-contact state. ..

Further, in the second embodiment, as described above, in the measurement state P2, the urging portion 210 is provided to bring the spindle 10 into contact with the non-contact bearing 20 by urging the spindle 10 in the axial direction. As a result, the urging unit 210 can easily switch to the measurement state P2. Further, when a dedicated urging portion 210 is provided to bring the spindle 10 into contact with the non-contact bearing 20, the urging force FF is set according to the magnitude of the contact reaction force FR from the contact sensor 2. , The misalignment of the spindle 10 can be sufficiently suppressed.

Other effects of the second embodiment are the same as those of the first embodiment.

(Modification example)
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

For example, in the first and second embodiments, the tool holding portion 40 has a collet member 41 capable of directly holding the straight shank (shank portion 1a (2a)) of the tool 1 and the contact sensor 2. , The present invention is not limited to this. In the present invention, the tool holding portion 40 does not have to have the collet member 41. For example, in a spindle device, it is known that the collet member is provided on the side of the tool instead of the tool holding portion.

In FIG. 10, the tool holding portion 40 has a holding hole for inserting the tool holding collet 310 to which the tool 1 is fixedly attached, and the rotary outer cylinder 320 is screwed and tightened to the spindle 10. It is configured to hold the tool holding collet 310.

In FIG. 11, the tool holding portion 40 has a holding hole for inserting the tool holding collet 330 to which the tool 1 is fixedly attached, and the tool holding collet 330 is moved by the advance / retreat of the draw bar 340 provided inside the spindle 10. It is configured to switch between gripping and releasing gripping. The tool holding collet 330 has a tapered shank portion 331, and when the tool holding collet 330 is inserted into the tool holding portion 40, the tapered surfaces come into contact with each other to regulate the axial center position and the axial center orientation. The drawbar 340 is provided in place of the push rod 82 shown in FIG. As shown in FIG. 11A, when the draw bar 340 is retracted, the lock lot 341 provided on the draw bar 340 presses the clamp claw 350 radially outward, and engages the clamp claw 350 with the shank portion 331 on the outer peripheral side. The tool 1 is gripped (clamped). As shown in FIG. 11B, when the draw bar 340 is advanced, the pressing of the clamp claw 350 by the lock lot 341 is released, so that the engagement between the shank portion 331 and the clamp claw 350 is released (released). ..

In the present invention, the tool holding portion 40 having the configuration shown in FIG. 10 or 11 may be provided. However, in the configuration in which the tool holding portion 40 has a collet member 41 capable of directly holding the straight shank (shank portion 1a (2a)) of the tool 1 and the contact sensor 2, one for each tool 1 and one for the contact sensor 2. Since the tool 1 and the contact sensor 2 are directly gripped by the collet member 41 attached to the spindle 10 in an accurately positioned state, the tool holding collet does not need to be provided, so that the axial center position and the axial center direction are oriented. It is preferable in that it can suppress the deviation and fix it with high accuracy.

Further, in the first and second embodiments, an example in which the spindle 10 is brought into contact with the non-contact bearing 20 in the axial direction (axial direction) (an example in which the spindle 10 is brought into contact with the axial bearing portion) is shown. Not limited to. In the present invention, the spindle 10 may be brought into contact with the non-contact bearing 20 in the radial direction. That is, a plurality of throttle holes are provided in the radial bearing portion 22 at equal angular intervals over the entire circumference, and the spindle 10 is not in contact with each other in the radial direction due to the balance of static pressure due to the compressed air discharged from each throttle hole. Be supported. Therefore, the radial facing surface 12a of the spindle 10 can be brought into contact with the radial bearing surface 22a of the radial bearing portion 22 by cutting off the pressure supply to any one or more of the plurality of throttle holes of the radial bearing portion 22. can. In this case, the movement of the spindle 10 can be suppressed by increasing the frictional force at the contact point between the radial facing surface 12a and the radial bearing surface 22a. In addition, in combination with the configuration shown in the first or second embodiment, the spindle 10 may be brought into contact with both the axial bearing portion 21 and the radial bearing portion 22.

Further, in the first embodiment, an example is shown in which the axial facing surface 11a of the spindle 10 is brought into contact with the other side axial bearing surface 21b by blocking the pressure supply to the throttle hole of the other side axial bearing surface 21b. However, the present invention is not limited to this. As shown in FIG. 12, the axial facing surface 11a of the spindle 10 may be brought into contact with the one-side axial bearing surface 21a by blocking the pressure supply to the throttle hole of the one-side axial bearing surface 21a.

Further, in the second embodiment, an example is shown in which the urging portion 210 urges the spindle 10 toward one end side (Z1 direction) to bring the one-side axial bearing surface 21a into contact with the axial facing surface 11a. , The present invention is not limited to this. In the second embodiment, conversely, the urging portion 210 is configured to urge the spindle 10 toward the other end side (Z2 direction) so that the spindle 10 is axially opposed to the other side axial bearing surface 21b. The surfaces 11a may be brought into contact with each other. In this case, the spindle 10 and the non-contact bearing 20 are in the same contact state as in the first embodiment (see FIG. 5).

Further, in the second embodiment, an example is shown in which the urging portion 210 is configured to urge the spindle 10 in a non-contact manner by air pressure, but the present invention is not limited to this. The urging portion 210 may be configured to urge the spindle 10 in direct contact with the spindle 10 by, for example, a pneumatic or hydraulic piston, an electric solenoid, or the like.

Further, in the first and second embodiments, in the measurement state P2, an example is shown in which the supply pressure of one of the axial bearing portions 21 and the other side is weakened or cut off from the other one. However, the present invention is not limited to this. In the present invention, for example, in the pneumatic source 60, a negative pressure source is provided separately from the positive pressure source, and negative pressure is supplied to either one side or the other side of the axial bearing portion 21, and the other. Positive pressure may be supplied to one side. This also allows the spindle 10 to come into contact with the non-contact bearing 20.

Further, in the first and second embodiments, the example of the portal machining center is shown, but the machine tool of the present invention includes a vertical machining center having no portal structure and a horizontal machining center in which the spindle 10 is provided in the horizontal direction. It may be.

1 Tool 2 Contact sensor 3 Work 10 Spindle 11a Axial facing surface 20 Non-contact bearing 21 Axial bearing 21a One side axial bearing surface (axial bearing surface)
21b Opposite side axial bearing surface (axial bearing surface)
22 Radial bearing part 30 Drive part 40 Tool holding part 41 Collet member 70 Fluid circuit 72 Switching valve 100, 101 Spindle device 110 Moving mechanism 120 Tool changing device 130 Control part 133 Discriminating part 200 Machine tool 210 Biasing part P1 Machining state P2 measurement Status

Claims (10)

With the spindle
A non-contact bearing that rotatably supports the spindle around the central axis in a non-contact manner,
A drive unit that rotationally drives the spindle and
A tool holding portion provided at one end of the spindle and holding a tool for processing the work or a contact sensor for measuring the work in a detachable manner is provided.
The non-contact bearing is a spindle device configured to be switchable to a measurement state in which the movement of the spindle is suppressed by supporting the spindle in a contact state when the contact sensor is mounted. The non-contact bearing is
Includes an axial bearing portion that supports the spindle from both sides in the axial direction in the axial direction, and a radial bearing portion that supports the spindle in the radial direction.
The spindle device according to claim 1, wherein in the measurement state, the axial bearing surface of the axial bearing portion and the axial facing surface of the spindle are configured to be in axial contact with each other. The axial bearing portion includes a one-side axial bearing surface that supports the spindle from one end side, and a other-side axial bearing surface that supports the spindle from the other end side opposite to one end side.
2. The non-contact bearing is configured such that the one-side axial bearing surface is separated from the main shaft and the other-side axial bearing surface is in contact with the axial facing surface of the main shaft in the measurement state. The spindle device described in. The non-contact bearing is a hydrostatic fluid bearing, and is
A fluid circuit for controlling the pressure supply to the hydrostatic fluid bearing is further provided.
The fluid circuit connects the axial bearing surface and the axial facing surface by weakening or blocking the supply pressure of one of the one end side and the other end side of the axial bearing portion than the other one. The spindle device according to claim 2 or 3, which is configured to be in contact. The hydrostatic fluid bearing is a hydrostatic air bearing.
The spindle device according to claim 4, wherein the fluid circuit includes a switching valve that switches between supplying and shutting off air pressure to any one of the axial bearings. The spindle device according to any one of claims 1 to 3, further comprising an urging portion that brings the spindle into contact with the non-contact bearing by urging the spindle in the axial direction in the measurement state. .. A discriminating unit that determines from the tool changer that the contact sensor is attached to the tool holding unit, and a discriminating unit.
The spindle device according to any one of claims 1 to 6, further comprising a control unit that controls switching the non-contact bearing to the measurement state when the contact sensor is mounted on the tool holding unit. .. The spindle device according to any one of claims 1 to 7, wherein the tool holding portion includes a straight shank type tool and a collet member capable of directly holding the contact sensor. The drive unit includes an induction motor.
The spindle device according to any one of claims 1 to 8, wherein the non-contact bearing is configured to stop the rotation of the spindle by contact with the spindle in the measurement state. The spindle device according to any one of claims 1 to 9,
A moving mechanism that moves the spindle device and the work relative to each other,
A machine tool comprising a tool changing device that holds the tool and the contact sensor detachably from the spindle of the spindle device.

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