TWI770317B - Spindle device and machine tool - Google Patents

Abstract

The spindle device of the present invention includes: a spindle; a non-contact bearing that rotatably supports the spindle in a non-contact manner; a drive part; The non-contact bearing is configured to be switchable to a measurement state in which the spindle is supported in a contact state to suppress movement of the spindle when the contact sensor is installed.

Description

Spindle device and machine tool

The present invention relates to a spindle device and a machine tool, and more particularly, to a spindle device and a machine tool including a spindle that can be equipped with a sensor for measuring a workpiece instead of a tool.

Conventionally, there has been known a spindle device including a spindle that can be equipped with a sensor for measuring a workpiece instead of a tool. Such a spindle device is disclosed in, for example, Japanese Patent Laid-Open No. 2006-326804.

The above-mentioned Japanese Patent Laid-Open No. 2006-326804 discloses a spindle device including: a spindle; a bearing for rotatably supporting the spindle; a motor for rotationally driving the spindle; At the front end of the main shaft, either a tool for machining a workpiece or a probe for measuring the diameter of the workpiece to be machined can be exchanged or removed by means of the tool clamping mechanism.

The bearing of the main shaft may be a contact-type ball bearing, although it is not specified in the above-mentioned Japanese Patent Laid-Open No. 2006-326804.

Here, in addition to contact-type rolling bearings such as ball bearings, non-contact bearings such as hydrostatic fluid bearings are also used for the bearings of the spindle device. Comparison of non-contact bearings and contact bearings, with the exception of the shaft In addition to the small friction coefficient and low heat generation, the bearing has low rigidity, and it is easy to move the main shaft by the amount of clearance between the main shaft and the bearing by external force. Therefore, in a spindle device using a non-contact bearing, when the probe is equipped with a contact sensor on the spindle to measure the workpiece, the spindle is deviated due to the contact reverse force from the workpiece, making accurate measurement difficult. problem point. For this reason, in a spindle device using a non-contact bearing, when a contact sensor is installed on the spindle to measure a workpiece, it is preferable that the measurement accuracy can be improved.

The present invention has been developed to solve the above-mentioned problems, and an object of the present invention is to provide a spindle device using a non-contact bearing, in which a contact sensor is installed on the spindle to measure a workpiece, which can improve the Spindle devices and machine tools for measuring accuracy.

The spindle device according to the first aspect of the present invention includes: a spindle; a non-contact bearing capable of non-contact support for rotating the spindle around a central axis; a drive unit for rotationally driving the spindle; The tool holding part of the tool for machining or the touch sensor that measures the workpiece, and the non-contact bearing are configured to switch to a measurement state in which the spindle is supported in a contact state to suppress movement of the spindle when the touch sensor is installed.

In this spindle device, the non-contact bearing is configured as described above, whereby when a contact sensor is mounted on the tool holder for workpiece measurement, the non-contact bearing is switched to the measurement state, and the non-contact bearing can be used for the contact state. to support the spindle. Therefore, the contact opposing force of the touch sensor acts on the spindle In the case of , the deflection of the main shaft due to the contact reverse force can be suppressed compared with the case of the main shaft that is kept in a non-contact state. Although the method of suppressing misalignment varies according to the relationship between the contact direction of the non-contact bearing and the main shaft and the direction of action of the contact reverse force, there is a movement limit that directly supports the contact reverse force on the bearing surface; the frictional resistance associated with the contact increase; and the generation of the close contact force between the bearing surface and the opposite surface of the main shaft side.

That is, when the main shaft is brought into contact with the non-contact bearing in the acting direction of the contact reverse force, since the main shaft supported on the bearing surface of the non-contact bearing does not move further, it is possible to effectively suppress the effect of the contact reverse force. Offset of the spindle. When the main shaft is brought into contact with the non-contact bearing in the direction in which the contact opposing force intersects, the movement of the main shaft can be suppressed by increasing the frictional force at the contact point. When the main shaft is brought into contact with the non-contact bearing in the opposite direction to the contact force, the main shaft can be supported by the close contact force between the bearing surface and the opposing surface on the main shaft side. That is, the bearing surface and the opposing surface on the main shaft side are generally smoothed by finish grinding or the like. Therefore, once the bearing surface and the opposing surface come into surface contact, they are in strong close contact and the movement of the main shaft can be suppressed. As a result of these, by switching the non-contact bearing to the measurement state for measurement, in the spindle device using the non-contact bearing, even when a contact sensor is installed on the spindle to measure the workpiece, the measurement accuracy can be improved. .

In the spindle device according to the first aspect, it is preferable that a non-contact bearing includes an axial bearing portion that supports the spindle axially from both sides in the axial direction, and a radial bearing portion that supports the spindle in the radial direction. Next, the axial bearing surface of the axial bearing portion is configured to be in axial contact with the axially opposite surface of the main shaft. With the above configuration, the axial bearing surface can be aligned with the axial direction of the main shaft. Opposite faces form face contact in the axial direction. As a result, due to the close contact of the surfaces, the deflection of the main shaft can be effectively suppressed even against contact reverse force in the axial direction or radial contact reverse force from the touch sensor. In addition, the axial position of the main shaft is positioned at the contact position between the non-contact bearing and the axial bearing surface, so that the positional accuracy of the main shaft in the axial direction can be improved. As a result, the workpiece can be measured with higher accuracy.

In this case, preferably, the axial bearing portion includes an axial bearing surface on one side that supports the main shaft from one end side, and an axial bearing surface on the other side that supports the main shaft from the other end side opposite to the one end side, and the non-contact bearing In the measurement state, the axial bearing surface on one side is separated from the main shaft, and the axial bearing surface on the other side is in contact with the axially opposite surface of the main shaft. With the above configuration, the other side axial bearing surface can be brought into contact with the axially opposite surface of the main shaft from the other end side, so even if the contact reverse force in the axial direction from the contact sensor is directed in the direction of pressing the main shaft If it acts (in the direction of the other end of the main shaft), the movement of the main shaft can be reliably prevented. Furthermore, the axial position of the main shaft can be positioned at the contact position with the axial bearing surface on the other side. As a result, it is possible to prevent the deflection of the contact reverse force and to improve both the axial position accuracy of the spindle in the measurement state.

In the above-mentioned configuration of the non-contact bearing including the axial bearing portion and the radial bearing portion, it is preferable that the non-contact bearing is a hydrostatic fluid bearing, and further includes a fluid circuit for controlling the supply pressure to the hydrostatic fluid bearing, and the fluid circuit is constituted in Among the one end side and the other end side of the axial bearing portion, the supply pressure of one of them is made weaker or blocked than that of the other, so that the axial bearing surface and the axially opposite surface are brought into contact. In the above configuration, only need to adjust (decreased or blocking) the supply pressure to the hydrostatic fluid bearing, the axial bearing surface can be easily contacted with the axially opposite surface. In addition, only a fluid circuit for supporting the main shaft in a non-contact manner by means of a hydrostatic fluid bearing is used, so even when the axial bearing surface is in contact with the axially opposing surface, the device configuration is not complicated.

In this case, preferably, the hydrostatic fluid bearing is a hydrostatic air bearing, and the fluid circuit includes a switching valve that switches the supply and blocking of the air pressure relative to any one of the axial bearing parts. With the above configuration, it is possible to easily switch the measurement state in which the axial bearing surface and the axially opposite surface are brought into contact with a simple configuration in which the switching valve is provided.

In the spindle device according to the first aspect described above, it is preferable to further include an urging portion that pushes the spindle in the axial direction to bring the spindle into contact with the non-contact bearing in the measurement state. With the above configuration, the measurement state can be easily switched by means of the pusher. In addition, when a dedicated urging portion is provided for contacting the main shaft with the non-contact bearing, the biasing force of the main shaft can be sufficiently suppressed by setting the urging force according to the magnitude of the contact reaction force from the contact sensor.

Preferably, the spindle device of the above-mentioned first aspect further includes: a determination unit for determining that the touch sensor is installed from the tool changing device to the tool holding part, and a control unit for installing the touch sensor in the tool holder. In the case of the tool holder, control is performed to switch the non-contact bearing to the measurement state. With the above configuration, even when the tool is used for measurement before machining or during machining, it can be switched to the measurement state when it is determined that the touch sensor is installed in the tool holder. As a result, it is not necessary for the user to switch to the measurement state, and the non-contact bearing can surely be switched to the measurement state during the measurement of the touch sensor.

In the spindle device according to the first aspect described above, it is preferable that the tool holding portion has a collet member capable of directly holding a straight shank type tool and a touch sensor. With the above configuration, unlike the case of removing the attached collet tool (contact sensor), there is no need to install a collet chuck for each tool (contact sensor), and the number of parts can be reduced to make the tool smaller change. Therefore, even when the tool changing device is provided with a touch sensor, the device configuration does not increase in size.

In the spindle device according to the first aspect, it is preferable that the drive unit includes an induction motor, and the non-contact bearing is configured to stop the rotation of the spindle by contacting the spindle in the measurement state. Here, in the case of using an induction motor, when the main shaft is not driven, the main shaft is idling. Therefore, when the touch sensor is mounted on the tool holder, if the central axis of the main shaft and the central axis of the touch sensor are not closely aligned, the front end of the touch sensor will vibrate, and the contact sensor will vibrate. Positional non-uniformity is a factor that reduces measurement accuracy. Therefore, according to the above-mentioned configuration, the rotation of the main shaft can be surely stopped in the measurement state, and the workpiece can be measured by the touch sensor. Therefore, in the configuration using the induction motor, it is easy to perform no special motor control. Improve measurement accuracy.

A machine tool according to a second aspect of the present invention includes: the spindle device according to one of the above-mentioned first aspects; a moving mechanism for relatively moving the spindle device and the workpiece; Tool changer for spindle removal.

In this machine tool, with the above-described configuration, as with the spindle device of the first aspect, the workpiece is mounted in the tool holding portion with the touch sensor. In the case of measurement, the non-contact bearing is switched to the measurement state, and the main shaft can be supported in the contact state. Therefore, when the contact reverse force of the contact sensor acts on the main shaft, compared with the case where the main shaft is held in the non-contact state, it can be suppressed. Offset of the main axis of the contact opposing force. As a result, in a machine tool equipped with a spindle device using a non-contact bearing, even when a touch sensor is attached to the spindle to measure a workpiece, the measurement accuracy can be improved.

2: touch sensor

10: Spindle

11: Flange

11a: Axial Opposite Surface

12: Shaft

12a: Radially Opposite Surface

20: Non-contact bearings

21: Axial bearing part

21a: Axial bearing surface on one side

21b: Axial bearing surface on the other side

22: Radial bearing part

22a: Radial bearing surface

30: Drive Department

31: Stator

32: Rotor

33: gimbal

40: Tool Holder

50: Shell

51: Access Department

60: Air pressure source

70: Fluid circuit

80: Switching mechanism

81: Actuator

82: putter

100: Spindle device

CL: Clearance

P1: Processing state

FIG. 1 is a schematic view showing the overall configuration of a machine tool including a spindle device according to a first embodiment.

Fig. 2 is a schematic longitudinal sectional view showing the spindle unit according to the first embodiment.

Fig. 3 is a schematic enlarged cross-sectional view illustrating the structure of the tool holding portion and the tool holding portion for tool replacement.

FIG. 4 is a schematic view of a spindle device for explaining a machining state.

Fig. 5 is a schematic diagram of a spindle device for explaining a measurement state.

FIG. 6 is a flowchart for explaining the flow of measurement processing using the touch sensor.

Fig. 7(A) is a diagram showing measurement of a standard gauge (A) and Fig. 7(B) is a diagram showing measurement of a workpiece.

Fig. 8 is a schematic longitudinal sectional view showing a spindle unit according to a second embodiment.

Fig. 9 is a schematic view of a spindle device for explaining the measurement state of the second embodiment.

Fig. 10 is a schematic view showing a first modification of the tool holding portion.

FIG. 11 is a schematic view showing a grip state (A) and a released state (B) of the second modification of the tool holding portion.

FIG. 12 is a schematic view showing a modification of the measurement state shown in FIG. 5 .

[Description of the preferred embodiment]

Hereinafter, embodiments of the present invention will be described based on the drawings.

[1st Embodiment]

Referring to FIGS. 1 to 5 , the spindle device 100 and the machine tool 200 including the spindle device 100 according to the first embodiment will be described.

(Outline of Spindle Unit and Machine Tool)

As shown in FIG. 1 , the spindle device 100 is driven to rotate around the central axis of the spindle 10 (see FIG. 2 ), whereby a tool 1 mounted on one end of the spindle 10 is rotated to process a workpiece 3 of the workpiece. device used. The spindle device 100 is assembled to the machine tool 200 and relatively moved with respect to the workpiece 3 by the moving mechanism 110 provided in the machine tool 200 . The machine tool 200 is a numerical control (NC) machine tool, which controls the relative movement (position and speed) of the tool 1 and the workpiece 3 by means of numerical information, and executes a continuous operation related to processing by means of the program 132 . Specifically, the machine tool 200 is a machining center including a spindle device 100 and a tool changing device 120 , and performs drilling, boring, and milling by replacing the tool 1 with the spindle device 100 . Various processing such as cutting.

In the first embodiment, as an example, the workpiece 3 is a mold for an optical lens, and an example in which precision machining of the mold is performed by using the machine tool 200 will be described. Since the spindle device 100 and the machine tool 200 of the first embodiment can measure the workpiece 3 with high precision by the touch sensor 2, it is particularly suitable for applications requiring high precision precision machining such as mold making.

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

The moving mechanism 110 is configured to relatively move the spindle device 100 and the workpiece 3 . The machine tool 200 relatively moves the spindle device 100 and the workpiece 3 in orthogonal three-axis directions at least in the vertical direction and two directions orthogonal to the horizontal plane. The relative movement between the spindle device 100 and the workpiece 3 may be only one of the spindle device 100 and the workpiece 3 , or both the spindle device 100 and the workpiece 3 may move. In the example of FIG. 1, the moving mechanism 110 moves the spindle device 100 in the Z direction in the up-down direction and the Y direction in the horizontal plane (the left-right direction in FIG. 1), so that the workpiece 3 is moved in the horizontal plane in the positive direction to the Y direction. It moves in the X direction of the intersection (the immediate side and the depth direction 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 machine base 140 on which the workpiece 3 is installed, and a machine base 141 that can move the machine base 140 in the X direction. The machine tool 200 includes a pair of columns 142 arranged on both sides in the Y direction of the machine base 141 , and a cross bar 143 hung on the upper ends of the pair of columns 142 . The cross bar 143 straddles the upper part of the machine table 140 and the machine base 141 so as to extend in the Y direction. The cross bar 143 is a support seat 144 which can move in the Y direction. The seat frame 144 supports the handpiece 145 provided with the spindle device 100 so as to be movable in the Z direction.

The moving mechanism 110 includes: a Z-axis moving mechanism 111 for moving the head 145 in the Z direction; a Y-axis moving mechanism 112 for moving the seat frame 144 in the Y direction; and an X-axis moving mechanism for moving the table 140 in the X direction 113. The Z-axis moving mechanism 111 , the Y-axis moving mechanism 112 , and the X-axis moving mechanism 113 respectively include, for example, a servo motor 114 with a built-in position detector, and a direct-acting mechanism (not shown) driven by the servo motor 114 . In addition, the moving mechanism 110 may include more moving axes than three axes. For example, the moving mechanism 110 may include a rotating shaft that rotates the head 145 at the axis center of the X direction (inclination of the tool 1 of the spindle device 100 with respect to the horizontal plane), or rotates the table 140 at the center of the Z axis (rotates the workpiece). 3 rotates in the horizontal plane).

The tool exchange device 120 has a function of holding a plurality of types of tools 1 detachably and exchanging the tool 1 mounted on the spindle 10 of the spindle device 100 . In the first embodiment, the tool changer 120 holds the touch sensor 2 in a removable manner in addition to the tool 1 . That is, the tool changer 120 is configured to detachably hold the tool 1 and the touch 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 for holding the tool 1 and the touch sensor 2 , and a motor 122 for driving the magazine 121 . The magazine 121 is formed in a disk shape, and has a plurality of holding holes (not shown) in the peripheral portion along the circumferential direction. The magazine 121 is held in each holding hole in a state in which the tool 1 or the touch sensor 2 is pulled upward. The motor 122 is configured to allow the magazine 121 to rotate around a central axis.

By the rotation of the magazine 121 , the predetermined holding hole of the magazine 121 can be positioned at the tool changing position with respect to the spindle device 100 . As a result, the machine tool 200 moves the spindle device 100 toward the tool changing position above the magazine 121, and can perform: removing the tool 1 or the touch sensor 2 mounted on the spindle device 100 and setting it at the tool changing position A holding hole, and the tool 1 or the touch sensor 2 held in the holding hole moving toward the tool exchange position are mounted on the spindle device 100 .

The control unit 130 is configured to be able to control the entire operation of the machine tool 200 . The control unit 130 is constituted by a processor such as a CPU. The control unit 130 includes a memory unit 131 in which various programs 132 for controlling the machine tool 200 including the machining program of the workpiece 3 are stored. The processor executes the program stored in the memory unit 131 , thereby causing the processor to operate as the control unit 130 of the machine tool 200 . Thereby, the control part 130 performs operation control of the spindle device 100 , operation control of the moving mechanism 110 , and operation control of the tool changing device 120 . The control unit 130 is, for example, a control panel provided in 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 into an assembly in which each of these parts is accommodated in the casing 50 .

The main shaft 10 is a shaft member extending up and down roughly at the center of the cylindrical casing 50 . The main shaft 10 is a solid shaft member, but in the example of Fig. 2, it has a hollow cylindrical shape (see Fig. 3 ). The main shaft 10 is driven by The movable portion 30 is rotationally driven around the central axis, and rotates the tool 1 attached to the tool holding portion 40 provided at one end (spindle end) of the spindle 10 . Hereinafter, for convenience, the side where the tool holder 40 of the spindle 10 is arranged is one end side (Z1 direction), and the opposite side to the tool holder 40 of the spindle 10 is the other end side (Z2 direction).

The main shaft 10 is provided with a flange portion 11 protruding radially outward on the outer surface. The flange portion 11 has a certain thickness and is formed in a disk shape. In the flange portion 11 , axially opposing surfaces 11 a facing the non-contact bearing 20 in the axial direction are formed on respective 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 diametrically opposed surface 12a diametrically opposed to the non-contact bearing 20 . In addition, the position of the flange portion 11 is not particularly limited, and the flange portion 11 may be arranged on one end side (the Z1 direction side) with respect to the shaft portion 12 .

The tool holder 40 is provided at one end of the main shaft 10 , and constitutes a detachable holding of the tool 1 for processing the workpiece 3 or the touch sensor 2 for measuring the workpiece 3 . The tool holder 40 is at one end of the hollow main shaft 10 and holds the tool 1 or the touch sensor 2 by engaging with the inserted tool 1 or the touch sensor 2 . Details of the tool holding portion 40 will be described later.

The non-contact bearing 20 is configured to support the main shaft 10 rotatably around the central axis in a non-contact manner. The non-contact bearing 20 is configured to support the main shaft 10 to be rotatable around the central axis in a non-contact manner at least when the main shaft 10 is driven to rotate. In other words, the non-contact bearing 20 is configured to rotatably support the machining state P1 of the spindle 10 in a non-contact state when the tool 1 is installed (see FIG. 4 ). Furthermore, in the first embodiment, the non-contact bearing 20 is mounted on the contact sensor 2 When set, the spindle 10 is supported in a contact state, whereby the spindle 10 can be switched to a measurement state P2 (see FIG. 5 ) in which the movement of the spindle 10 is suppressed. As the non-contact bearing 20, a hydrostatic fluid bearing using oil or air as a working fluid, or a magnetic bearing can be used. In the first embodiment, the non-contact bearing 20 is a hydrostatic fluid bearing, particularly a hydrostatic air bearing. The hydrostatic air bearing is a bearing that introduces the pressurized gas into the gap CL between the bearing and the main shaft, and supports the load (self-weight and contact counter force) acting on the main shaft 10 in a non-contact manner by means of the balance of gas pressure.

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

The thrust bearing portion 21 has a pair of thrust 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 an axial bearing surface 21a on one side that supports the main shaft 10 from one end side, and an axial bearing surface 21b on the other side that supports the main shaft 10 from the other end side. In addition, the axial bearing surface 21a on one side and the axial bearing surface 21b on the other side are both examples of the "axial bearing surface" within the scope of the patent application. The axial bearing surface 21 a on one side and the axial bearing surface 21 b on the other side are formed in annular shapes when viewed in the axial direction, respectively, and are provided in the axial direction from the axially opposing surface 11 a of the flange portion 11 with a small gap CL interposed therebetween. relatively. Compressed air is supplied to the axial bearing portion 21 from an air pressure source (positive pressure source) 60 through a fluid circuit 70 to be described later and a passage portion 51 of the casing 50 . The one-side thrust bearing surface 21a and the other-side thrust bearing surface 21b are provided with orifices (not shown) for releasing compressed air toward the clearance CL with respect to the axially opposing surface 11a, respectively. Thereby, the axial bearing portion 21 can be supplied to the flange portion 11 from the axial bearing surface 21 a on one side and the axial bearing surface 21 b on the other side, respectively. The balance of the pressure of the working fluid (air) on both sides of the axial direction supports the axial direction (axial direction) of the main shaft 10 in a non-contact manner.

The radial bearing portion 22 has a radial bearing surface 22 a formed concentrically with the shaft portion 12 of the main shaft 10 . The radial bearing surfaces 22a are provided to face each other with a small gap CL from the radially opposing surface 12a of the main shaft 10 . Compressed air is supplied to the radial bearing portion 22 through the passage portion 51 . The radial bearing surface 22a is provided with an orifice (not shown) for releasing compressed air toward the gap CL with the radially opposing surface 12a. Thereby, the radial bearing portion 22 can perform the radial direction of the main shaft 10 without contact by the balance of the pressure of the working fluid (air) supplied from the radial bearing surface 22a to the gap CL between the radial bearing surface 22a and the radially opposite surface 12a. (radial direction) support.

In addition, two radial bearing portions 22 are provided at positions spaced apart in the axial direction of the main shaft 10 . Thereby, the fall of the main shaft 10 is prevented. The radial bearing portion 22 on the other end side in the axial direction is a bearing body provided in an L-shaped cross-section common to the axial bearing portion 21 .

In order to suppress the pressure fluctuation and unevenness during the rotational drive of the main shaft 10, the bearing surfaces (the axial bearing surface 21a on the one side, the axial bearing surface 21b on the other side, and the radial bearing surface 22a) are opposed to the main shaft 10. The surfaces (the axially opposing surface 11a, the radially opposing surface 12a) are constituted by finely ground surfaces. That is, the bearing surfaces and the opposing surfaces are formed with extremely small surface roughness and high dimensional accuracy, respectively. The size of the clearance CL between the axial bearing portion 21 and the radial bearing portion 22 and the main shaft 10 is, for example, about 8 μm or more and 20 μm or less. The size of the clearance CL between the axial bearing portion 21 and the main shaft 10 and the size of the clearance CL between the radial bearing portion 22 and the main shaft 10 may also be different.

In addition, the spindle device 100 includes a non-contact shaft to a hydrostatic fluid bearing The carrier 20 controls the fluid circuit 70 of the pressure supply. The fluid circuit 70 communicates with the non-contact bearing 20 and is connected to an external air pressure source 60 through a pressure regulating valve 71 (see FIG. 4 ). Thereby, compressed air of a predetermined pressure is supplied to the non-contact bearing 20 through 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 rotatably drive the main shaft 10 . The drive unit 30 is configured to be connected to the other end of the main shaft 10 , and to rotate and drive the main shaft 10 directly around the central axis. The drive unit 30 is an electric motor capable of rotating at a height of about 60,000 rpm, and is a built-in motor built into the casing 50 . The motor may be a synchronous motor or an induction motor, but in the first embodiment, the drive unit 30 is constituted by an induction motor. In an induction motor, an induced current is generated in the rotor 32 by the rotating magnetic field generated by the stator 31 , and the rotor 32 is rotated 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 main shaft 10 . The stator 31 is fixed to the housing 50 to surround the radially outer side of the rotor 32 .

Furthermore, in the example of FIG. 2 , the spindle device 100 includes a switching mechanism 80 for switching between clamping (grip) and release (release of the grip) of the tool 1 of the tool holder 40 . The switching mechanism 80 includes an actuator 81 provided on the other end side (Z2 direction side) of the main shaft 10 and a push rod 82 inserted into the hollow main shaft 10 and extending from the other end side to the vicinity of the tool holder 40 . The actuator 81 is constituted by, for example, a pneumatic or hydraulic piston, an electric solenoid, or the like, and moves the push rod 82 forward and backward in the axial direction.

(replacement of tools)

In the configuration example of the first embodiment shown in FIG. 3, the tool holding portion 40 It constitutes a straight handle portion 1a ( 2a ) that can directly hold the tool 1 or the touch sensor 2 , and holds the tool 1 or the touch sensor 2 . That is, the tool holding part 40 has the collet member 41 which can directly hold the straight handle type tool 1 and the touch sensor 2 .

Specifically, the tool holder 40 includes: a collet member 41 ; a hollow cylindrical sleeve 42 fixed to one end of the main shaft 10 ; a coil spring 43 ; and a collet nut 44 . One end side of the sleeve 42 is formed with a clamping hole formed in a tapered shape as the inner diameter decreases toward the other end side (Z2 direction side), and the collet member 41 is inserted. The collet member 41 has a cylindrical shape capable of holding the shank 1 a ( 2 a ) on the inner peripheral side, and is inserted into the sleeve 42 from one end side (the Z1 direction side) of the sleeve 42 . One end side portion of the collet member 41 corresponds to a clamping hole of the sleeve 42, and the outer diameter thereof becomes smaller toward the other end portion, and is formed in a tapered shape.

An axially extending notch 41 a is formed in the collet member 41 from an intermediate position across one end. The collet member 41 extends through the sleeve 42 toward the other end, and the other end of the collet member 41 is provided with a collet nut 44 . Then, the collet member 41 is urged toward the other end side (Z2 direction side) by the coil spring 43 provided between the sleeve 42 and the collet nut 44 . As a result of the coil spring 43 urging the collet member 41 toward the deep side (Z2 direction side) of the slanted tapered clamping hole of the sleeve 42, one end of the collet member 41 (the part where the notch 41a is formed) is in the The radially inner side is compressed and deformed to reduce the inner diameter. The shank 1a ( 2a ) of the tool 1 or the touch sensor 2 inserted into one end of the collet member 41 holds (holds) the tool 1 or the touch sensor 2 by the radial compression force. .

When the push rod 82 is advanced toward the tool holding portion 40 by the actuator 81 of the switching mechanism 80, the front end of the push rod 82 contacts the other end of the collet member 41, and the The collet member 41 is pressed toward one end side (Z1 direction side). The coil spring 43 is compressed so that the collet member 41 is pushed toward one end side only by a predetermined amount by applying a urging force larger than the urging force of the coil spring 43 by the switching mechanism 80 . The collet member 41 weakens the radial compression force only by the amount pushed out from the tapered hole, thereby weakening the gripping force of the tool 1 or the shank 1a ( 2a ) of the touch sensor 2 . As a result, the holding of the tool 1 or the touch sensor 2 can be released (released) by the operation of the actuator 81 .

The tool 1 and the touch sensor 2 are held in the magazine 121 of the tool changer 120 so that the handle 1a ( 2a ) faces upward (Z1 direction). During tool replacement, the machine tool 200 moves the spindle device 100 above the holding hole at the tool replacement position under the control of the control unit 130, and inserts the shank 1a (2a) into the collet member 41 with the push rod 82 advanced. internal. Then, the machine tool 200 holds the shank 1 a ( 2 a ) of the tool 1 or the machine tool 2 by the collet member 41 by retracting the push rod 82 . Thereby, the tool 1 or the touch sensor 2 is held by the tool holding portion 40 . When the tool 1 or the touch sensor 2 is returned to the tool changer 120, the machine tool 200 is at the tool change position, and the push rod 82 is advanced with the tool 1 or the touch sensor 2 arranged in the original holding hole. The grip of the tool holder 40 is released.

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

(Processing status and measurement status)

Next, the machining state when the tool 1 is installed in the spindle device 100 to perform machining, and the measurement state in which the touch sensor 2 is installed in the spindle device 100 to measure the tool 3 will be described.

As described above, in the first embodiment, the non-contact bearing 20 is in the machining state P1 (see FIG. 4 ) in which the spindle 10 is rotatably supported in a non-contact state when the tool 1 is installed, and the contact sensor 2 During the installation, by supporting the main shaft 10 in a contact state, it is possible to switch to a measurement state P2 in which the movement of the main shaft 10 is suppressed (see FIG. 5 ).

(Processing state)

First, as shown in FIG. 4 , in the machining state P1 , the compressed air from the air pressure source 60 is supplied to the one side thrust bearing surface 21 a and the other side thrust bearing surface of the thrust bearing portion 21 through the fluid circuit 70 . Both sides of 21b. Thereby, the main shaft 10 is axially supported with respect to the axial bearing portion 21 in a non-contact state. In addition, in the processing state P1 , the compressed air from the air pressure source 60 is supplied to each of the radial bearing surfaces 22 a of the two radial bearing portions 22 . Thereby, the main shaft 10 is radially supported with respect to the radial bearing portion 22 in a non-contact state. As a result of these, the main shaft 10 is driven by the air pressure supplied to the clearance CL with the non-contact bearing 20 . A state in which the movement in the axial direction (Z direction) and the radial direction (XY direction) is restricted without contact, and is rotatably supported around the central axis.

In this state, the spindle 10 is rotationally driven by the drive unit 30 to rotate the tool 1 attached to the spindle 10 at a high speed. Then, the spindle device 100 and the workpiece 3 are relatively moved by the Z-axis moving mechanism 111 , the Y-axis moving mechanism 112 , and the X-axis moving mechanism 113 included in the moving mechanism 110 . Cutting is performed by bringing the tool 1 into contact with the workpiece 3 .

(measurement status)

On the other hand, as shown in FIG. 5, in the measurement state P2, the non-contact bearing 20 is configured such that the thrust bearing surface (the other side thrust bearing surface 12b) of the thrust bearing portion 21 faces the axial direction of the main shaft 10. The faces 11a make axial contact.

That is, the supply pressure to the non-contact bearing 20 is adjusted so that the main shaft 10 is brought into contact with the non-contact bearing 20 . In the measurement state P2, the fluid circuit 70 is configured such that 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 is weaker than that of the other one, or blocking, whereby the axial bearing surface is brought into contact with the axially opposite surface 11a.

More specifically, in the first embodiment, the fluid circuit 70 includes the switching valve 72 for switching the supply (ON) and blocking (OFF) of the air pressure with respect to any one of the axial bearing portions 21 . That is, in the measurement state P2, the supply of air pressure to any one of the axial bearing parts 21 is blocked by the switching valve 72, so that the main shaft 10 is moved on the blocked side, so that the axial bearing surface and the axial The opposing surfaces 11a are in contact.

The fluid circuit 70 is provided with joints with the axial bearing surface 21a on one side, respectively. The flow passage 73 communicated with the orifice, and the flow passage 74 communicated with the orifice of the other side axial bearing surface 21b. The switching valve 72 is arranged on a flow passage 74 that communicates with the orifice of the other side axial bearing surface 21b. Therefore, by the switching valve 72, the compressed air is continuously supplied to the one side thrust bearing surface 21a, and the compressed air is supplied and blocked to the other side thrust bearing surface 21b. By blocking the supply of compressed air to the other side axial bearing surface 21b, only the part of the gap CL between the one side axial bearing surface 21a and the one side thrust bearing surface 21a becomes high pressure, so that the main shaft 10 faces the other side axial bearing surface 21b. move sideways.

With the above configuration, in the first embodiment shown in FIG. 5, the non-contact bearing 20 is configured in the measurement state P2, one side axial bearing surface 21a is separated from the main shaft 10, and the other side axial bearing surface 21b is connected to the main shaft. The axially opposite faces 11a of 10 are in contact. The main shaft 10 moves toward the other axial end (Z2 direction) only by an amount (about 8 μm to 20 μm) of the size of the gap CL between the other side axial bearing surface 21b and the axially opposing surface 11a. As a result, the other side thrust bearing surface 21b is brought into surface contact with the axially opposing surface 11a.

In the measurement state P2, the axially opposing surface 11a of the main shaft 10 is in contact with the other side axial bearing surface 21b, so that the axial (Z direction) position of the main shaft 10 is more accurately positioned between the other side axial bearing surface 21b and the other side axial bearing surface 21b. The contact position of the axially opposite surface 11a. In addition, the axial bearing portion 21 supports the external force toward the other end side (Z2 direction) in the axial direction of the main shaft 10, and the movement of the main shaft 10 is restricted so that the main shaft 10 does not move toward the other end side.

Here, unlike a synchronous motor in which a permanent magnet is provided in the rotor, the induction motor only provides a conductor, so that the rotor 32 (spindle 10 ) can be freely rotated when the motor is not driven. In contrast to this, as mentioned above, the non-contact shaft The bearing surface of the bearing 20 and the opposing surface of the main shaft 10 are each formed to be smooth by finish grinding, and the other side axial bearing surface 21b and the axial opposing surface 11a are strongly in close contact with each other in a surface contact state. Therefore, in the measurement state P2, the rotation of the main shaft 10 is stopped. As described above, the non-contact bearing 20 is configured to stop the rotation of the main shaft 10 by the contact with the main shaft 10 in the measurement state P2. Similarly, in the measurement state P2, the axial movement of the main shaft 10 is suppressed by the close contact between the other side axial bearing surface 21b and the axially opposing surface 11a.

In this state, the spindle device 100 and the workpiece 3 are relatively moved by the moving mechanism 110 , and the contact sensor 2 is brought into contact with the object to be measured, such as the workpiece 3 , and thereby the size of the object to be measured, or the coordinates of the moving mechanism 110 are measured. Precise measurement of the contact position of the system.

The measurement by the touch sensor 2 is, for example, the measurement of the external shape or the position of the workpiece 3 (see FIG. 7 ) and the measurement of the shape of the workpiece. For example, the outer shape of the rectangular parallelepiped workpiece 3 is measured by the contact between the horizontal direction (the radial direction of the main shaft 10 ) of the four side surfaces with respect to the horizontal direction and the vertical direction (the axial direction of the main shaft 10 ) of the upper surface. . For example, the shape of the surface to be machined formed on the upper surface of the workpiece 3 is in contact with a plurality of measurement points in the surface of the workpiece in the vertical direction (axial direction of the spindle 10 ), so that the three-dimensional positions of the obtained plurality of measurement points are The distribution is approximated and measured by obtaining the shape of the machined surface.

Therefore, in particular, when the touch sensor 2 is brought into contact with the axial direction (Z direction) from above the object to be measured, there is a possibility that the contact sensor 2 is in contact with the object to be measured and the other end side in the axial direction is The contact reverse force FR (refer to FIG. 5 ) (in the Z2 direction) acts on the main shaft 10 . On the structure of the touch sensor 2, The pressing force against the object to be measured is about 0.1N to 1N in the horizontal direction, and increases to about 1N to 7N in the axial direction. In the first embodiment, in the measurement state P2, the other side axial bearing surface 21b is brought into contact with the axially opposing surface 11a, thereby supporting the contact reaction force FR in the axial direction to prevent the main shaft 10 from being displaced. In addition, since the pressing force is small in the measurement in the horizontal direction, displacement in the axial direction is sufficiently prevented by the close contact between the other side axial bearing surface 21b and the axially opposing surface 11a.

When returning to the machining state P1 after switching to the measurement state P2, as shown in FIG. 4, the switching valve 72 is switched to supply compressed air to the other side axial bearing surface 21b, thereby releasing the other side shaft The contact between the bearing surface 21b and the axially opposing surface 11a is switched to the machining state P1.

The switching between the machining state P1 and the measurement state P2 is controlled by the control unit 130 according to whether the device mounted on the spindle 10 is the tool 1 or the touch sensor 2 . That is, in the first embodiment, the spindle device 100 includes the determination unit 133 for determining that the touch sensor 2 is attached to the tool holding unit 40 from the tool changing device 120 . In addition, the control unit 130 is configured to perform control to switch the non-contact bearing 20 to the measurement state P2 when the touch sensor 2 is mounted on the tool holding unit 40 .

When the control unit 130 controls to execute a continuous machining operation according to the program 132 that specifies the machining operation of the machine tool 200 , the determination unit 133 is installed in the tool 1 or the touch sensor 2 is determined. When the determination unit 133 determines that the touch sensor 2 is installed, the control unit 130 controls the switching valve 72 of the fluid circuit 70 to block the compressed air toward the other axial bearing surface 21b. When the determination unit 133 determines that the tool 1 is mounted, the control unit 130 controls the cutting of the fluid circuit 70 . The valve 72 is replaced, and compressed air is supplied to the other side axial bearing surface 21b.

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

(Measurement action control)

Next, referring to FIG. 6 , the measurement operation control is described using the touch sensor 2 . Here, an example of measuring the position and shape of the workpiece 3 when the machine tool 200 processes the workpiece 3 will be described.

In step S1 , the control unit 130 installs the touch sensor 2 on the tool holding unit 40 according to the program 132 .

In step S2 , the determination unit 133 determines whether or not the touch sensor 2 is mounted on the tool holding unit 40 of the spindle 10 . When the touch sensor 2 is not installed, the measurement operation does not start.

When the touch sensor 2 is installed, 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, and the supply of compressed air to the orifice from the other side axial bearing surface 21b is blocked. As a result, the non-contact bearing 20 is brought into contact with the main shaft 10 to suppress the movement of the main shaft 10 .

Next, in steps S4 and S5, the control section 130 measures the reference gauge 4 using the touch sensor 2, thereby performing zero adjustment (normalization).

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

The reference gauge 4 shown in Fig. 7(A) is a holder manufactured in advance with high dimensional accuracy using ceramics or the like, and has, for example, a ring shape. The control unit 130 controls the movement mechanism 110 in the measurement state P2 to contact the touch probes 2b of the touch sensor 2 at plural places on the inner peripheral surface of the reference gauge 4 to obtain reference position coordinates in the horizontal plane (in the XY plane). Moreover, the control part 130 touches the touch probe 2b of the touch sensor 2 to the upper surface of the reference|standard meter 4, and acquires the reference position coordinate of the Z direction.

In step S5 , the control unit 130 sets the zero points in the horizontal direction (XY direction) and the vertical direction (Z direction) based on the acquired reference position coordinates of the reference device 4 . This zero point is a reference position for the position and shape measurement of the workpiece 3 .

In step S6 , the control unit 130 uses the touch sensor 2 to measure the position and shape of the workpiece 3 . The control unit 130 controls the moving mechanism 110 in the measurement state P2, and as shown in FIG. 7(B), the touch probe 2b of the touch sensor 2 is brought into contact with the outer surfaces (four sides) of the workpiece 3, and each surface is measured. The horizontal position of the workpiece 3 on the side. Moreover, the control part 130 measures the height position (Z direction position) of the upper surface of the workpiece 3 by touching the touch probe 2b of the touch sensor 2 to the upper surface of the workpiece 3 . Moreover, the control part 130 measures the shape of the to-be-processed surface by bringing the touch-type probe 2b of the touch-type sensor 2 into contact with a plurality of measurement points set on the to-be-processed surface of the workpiece|work 3. Thereby, the position and shape of the workpiece 3 are precisely measured with reference to the zero point measured by the reference instrument 4 .

After the measurement is completed, the control unit 130 determines in step S7 whether or not to perform correction processing. For example, as shown in Figure 7(B), from the measurement results, confirm the When the workpiece 3 has already been formed into a predetermined shape, the control unit 130 ends the measurement process because correction processing is not required. If the workpiece 3 is not formed into a predetermined shape, the control unit 130 proceeds to step S8.

In step S8 , the control unit 130 mounts the tool 1 from the tool changing device 120 to the tool holding unit 40 instead of the touch sensor 2 . In step S9 , the determination unit 133 determines whether or not the tool 1 is attached to the tool holding unit 40 of the spindle 10 . When the tool 1 is not installed, the machining operation does not start.

When the tool 1 is already installed, 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, and the compressed air is supplied to the orifice of the other side axial bearing surface 21b. As a result, the non-contact bearing 20 is separated from the main shaft 10 to rotatably support the main shaft 10 in a non-contact state.

Then, the control unit 130 executes the machining control operation according to the control program. That is, the control unit 130 rotates the main shaft 10 at a high speed by the drive unit 30, and executes the machining of the workpiece 3 based on the position information and shape information obtained by the measurement.

In addition, the measurement of the workpiece 3 can be performed at a predetermined timing during processing. The timing at which the measurement of the workpiece 3 is performed can be determined by the program 132 that defines the machining operation. Therefore, when the touch sensor 2 is installed (step S1 ) on the main shaft 10 in order to measure the workpiece 3 during processing, the above-mentioned steps S2 to S6 are performed to measure the workpiece 3 . In addition, when the position and shape of the unprocessed workpiece 3 are measured before the machining of the workpiece 3, steps S1 to S6 are performed to measure the position and shape of the workpiece 3, and after steps S8 to S10 are performed, the tool is replaced, and the start is started based on the measurement results. Machining of tool 3.

(Effect of the first embodiment)

In the first embodiment, the following effects can be obtained.

In the first embodiment, as described above, when the touch sensor 2 is installed, the non-contact bearing 20 can be switched to the measurement state P2 in which the movement of the main shaft 10 is suppressed by supporting the main shaft 10 in a contact state. When the type sensor 2 is mounted on the tool holder 40 to measure the workpiece 3, the non-contact bearing 20 is switched to the measurement state P2, and the spindle 10 can be supported by the non-contact bearing 20 in a contact state. Therefore, when the contact reaction force FR of the touch sensor 2 acts on the main shaft 10, the deviation of the main shaft 10 due to the contact reaction force FR can be suppressed compared with the case where the main shaft 10 is kept in a continuous non-contact state.

Specifically, for example, in the spindle device 100 in which the spindle rotates at a high speed of about 60,000 rpm, the rigidity of the hydrostatic air bearing in the axial direction (axial direction) is usually about 10 N/μm to about 20 N/μm. On the other hand, when the touch probe 2b is pressed in the axial direction with respect to the object to be measured, the pressing force 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 has a displacement of 0.7 μm, which makes it difficult to precisely measure the precision required for the mold. On the other hand, according to the configuration of the above-described first embodiment, since the main shaft 10 is mechanically contacted with the non-contact bearing 20 in the acting direction of the contact reaction force FR, the deviation of the main shaft 10 is effectively suppressed. As a result, the measurement is performed in a state where the non-contact bearing 20 is switched to the measurement state P2, whereby in the spindle device 100 using the non-contact bearing 20, the workpiece 3 is measured even if the contact sensor 2 is attached to the spindle 10. , the measurement accuracy can still be improved.

Also, in the first embodiment, as described above, in the measurement state P2, the thrust bearing surface (the other side thrust bearing surface 21b) of the thrust bearing portion 21 and the thrust bearing surface 11a of the main shaft 10 are axially aligned. Since the non-contact bearing 20 is configured to be in contact, the axial bearing surface (the other axial bearing surface 21b ) and the axially opposing surface 11a of the main shaft 10 can be brought into surface contact in the axial direction. As a result, due to the close contact of the surfaces, the deflection of the main shaft 10 can be effectively suppressed even with respect to the contact reverse force FR in the axial direction from the touch sensor 2 or with respect to the contact reverse force in the radial direction. . Furthermore, since the axial position of the main shaft 10 is positioned at the contact position with the axial bearing surface of the non-contact bearing 20 , the positional accuracy of the main shaft 10 in the axial direction can be improved. As a result, the measurement of the workpiece 3 can be performed with higher accuracy.

Furthermore, the first embodiment is configured such that in the measurement state P2, one side thrust bearing surface 21a is separated from the main shaft 10 and the other side thrust bearing surface 21b is in contact with the axially opposing surface 11a of the main shaft 10 as described above. Non-contact bearing 20 . Thereby, the other side axial bearing surface 21b on the other end side (the Z2 direction side) is brought into contact with the axially opposing surface 11a of the main shaft 10, so even if the contact reverse force FR in the axial direction from the contact sensor 2 (Refer to Fig. 5) When the action is directed in the direction (Z2 direction) in which the spindle 10 is press-fitted, the spindle 10 can be reliably prevented from moving. Furthermore, the axial position of the main shaft 10 can be positioned at the contact position with the other side axial bearing surface 21b. As a result, both the prevention of the misalignment due to the contact reaction force FR and the improvement of the positional accuracy in the axial direction of the main shaft 10 in the measurement state P2 can be achieved.

Furthermore, in the first embodiment, as described above, the supply of any one side (the other side) of the axial bearing portion 21 is blocked by blocking the supply of either one side or the other side. The fluid circuit 70 is configured so that the thrust bearing surface (the other side thrust bearing surface 21b ) and the axially opposing surface 11a are brought into contact with each other under pressure. Thereby, the axial bearing surface and the axially opposing surface 11a can be easily brought into contact only by adjusting (blocking) the supply pressure to the hydrostatic fluid bearing. Furthermore, only the fluid circuit 70 for supporting the main shaft 10 in a non-contact manner by means of a hydrostatic fluid bearing is used, so even when the axial bearing surface is in contact with the axially opposing surface 11a, the device configuration is not complicated. Furthermore, instead of blocking the supply pressure to the other side, only the supply pressure to the other side may be made weaker than the supply pressure to the one side. As long as the supply pressure to the other side is sufficiently smaller than the supply pressure to the one side, the axial bearing surface can be brought into contact with the axially opposite surface 11a by the pressure difference. Therefore, as long as the axial bearing surface is brought into contact with the axially opposing surface 11a, it is not necessary to completely block the supply of pressure to the other side.

In the first embodiment, as described above, the fluid circuit 70 is provided with a switching valve 72 that switches the supply and blocking of the air pressure with respect to any one of the axial bearing portions 21 . Thereby, only with the simple structure provided with the switching valve 72, it is possible to easily switch to the measurement state P2 in which the axial bearing surface is in contact with the axially opposing surface 11a.

In addition, in the first embodiment, as described above, the determination unit 133 that determines whether the touch sensor 2 is attached to the tool holder 40 from the tool changing device 120 is provided and the touch sensor 2 is attached to the tool holder. In the case of the part 40, the control part 130 performs control to switch the non-contact bearing 20 to the measurement state P2. This makes it possible to switch to the measurement state P2 even when it is determined that the touch sensor 2 is installed in the tool holder 40 in the measurement before the start of machining by the tool 1 or in the measurement during the machining. As a result, the user does not switch If it is necessary to be in the measurement state P2, the non-contact bearing 20 can be switched to the measurement state P2 with certainty during the measurement of the touch sensor 2 .

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 handle type tool 1 and the touch sensor 2 . As a result, unlike in the case of removing the tool 1 (contact sensor 2) with a collet, it is not necessary to provide a collet chuck for each tool 1 (contact sensor 2), and parts can be eliminated. The number miniaturizes the tool 1 . Therefore, even in the case where the touch sensor 2 is provided in the tool 1 replacement device, the device configuration does not increase in size.

In the first embodiment, as described above, the drive unit 30 is constituted by an induction motor, and the non-contact bearing 20 is configured to stop the rotation of the main shaft 10 by contacting the main shaft 10 in the measurement state P2. As described above, when the induction motor is used, the main shaft 10 is idling when the main shaft 10 is not driven. Therefore, when the tool holder 40 is equipped with the touch sensor 2, if the central axis of the spindle 10 and the central axis of the touch sensor 2 are not exactly aligned, the front end of the touch sensor 2 may be Swing vibration is a cause of a decrease in measurement accuracy due to uneven contact positions of the workpiece 3 and the reference gauge 4 . Therefore, with the above-described configuration, the workpiece 3 can be measured by the touch sensor 2 in a state where the rotation of the spindle 10 is surely stopped in the measurement state P2. Therefore, in the configuration using an induction motor, no special motor control is required. The measurement accuracy can be easily improved.

Furthermore, in the first embodiment, the machine tool 200 including the spindle device 100 configured as described above is configured, whereby the contact sensor 2 is installed even in the machine tool 200 including the spindle device 100 using the non-contact bearing 20 . When the spindle 10 measures the workpiece 3, the measurement accuracy can still be improved.

[Second Embodiment]

Next, referring to Fig. 8 and Fig. 9, the spindle device 101 of the second embodiment will be described. The second embodiment is different from the first embodiment in which the measurement state P2 is switched by the pressure supply to the axial bearing surface 21b on the other side of the axial bearing portion 21. The configuration of the pusher 210 will be described. In addition, in the second embodiment, the configuration other than the spindle device 101 is the same as that in the above-described first embodiment, so the description is omitted. In addition, in 2nd Embodiment, about the same structure as the said 1st Embodiment, the same code|symbol is attached|subjected and description is abbreviate|omitted.

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

The pushing portion 210 applies an external force to the main shaft 10 and pushes it toward the non-contact bearing 20 . Thereby, in the measurement state P2 (see FIG. 9 ), the main shaft 10 is brought into contact with the non-contact bearing 20 . Due to the contact between the main shaft 10 and the non-contact bearing 20, even if the contact reverse force FR of the contact probe 2b acts on the main shaft 10, the movement of the main shaft 10 can be suppressed.

The pushing portion 210 is not particularly limited as long as it is a configuration capable of imparting an external force to the main shaft 10 . In the example of FIG. 8, the urging|biasing part 210 is arrange|positioned at the other end side (Z2 direction side) with respect to the axial direction with respect to the drive part 30, and is comprised so that the main shaft 10 is urging|biased by air pressure. That is, compressed air is supplied to the pushing portion 210 through the fluid circuit 70 . The pushing portion 210 has an annular supply surface 211 opposite to the gimbal 33 provided at the other end portion in the axial direction of the rotor 32 and through which the push rod 82 is inserted. The pusher 210 is configured to discharge compressed air to the gimbal 33 from an orifice (not shown) provided on the supply surface 211 .

As shown in FIG. 9 , the fluid circuit 70 can switch the supply and blocking of the pressure to the pushing portion 210 by the switching valve 220 . As a result, in the open (supply) state of the switching valve 220 , the gimbal 33 , the rotor 32 , and the main shaft 10 connected to these are moved toward the one end side in the axial direction ( Z1 ) by the air pressure supplied from the pusher 210 direction) bounce and push. Thereby, the non-contact bearing 20 is configured to switch to the measurement state P2 in which the spindle 10 is supported in the contact state and the movement of the spindle 10 is suppressed when the switching valve 220 is switched to the open state.

In the closed (blocked) state of the switching valve 220, the spring push is released by blocking the supply of compressed air, so that the spindle 10 is rotatably supported by the non-contact bearing 20 in a non-contact state. As a result, the non-contact bearing 20 is configured to switch to the machining state P1 in which the spindle 10 can be rotatably supported in a non-contact state, as shown in FIG. 8 , once the switching valve 220 is switched to the closed state.

As described above, in the example of FIG. 9, the urging portion 210 is configured to make the axial bearing surface 21a on one side contact the axially opposing surface 11a by urging the main shaft 10 toward one end side (Z1 direction).

Therefore, in the case of the second embodiment, in the measurement state P2, with respect to the flange portion 11 of the main shaft 10, the other end side (the Z2 direction side) in the acting direction of the axial contact reaction force FR is at the opposite end to the other end (the Z2 direction side). A gap is generated between the axial bearing surfaces 21b on one side. Therefore, when the contact reaction force FR is larger than the urging force FF of the urging portion 210, there is a possibility that the main shaft 10 is displaced on the other end side.

At this time, the pressure on the other end side of the thrust bearing portion 21 increases as the clearance CL between the other side thrust bearing surface 21b and the axially opposing surface 11a decreases. Therefore, the resultant force of the self-weight of the main shaft 10, the thrust force FF, the pressure FP on the other end side, and the contact reaction force FR may stop the displacement of the main shaft 10 at a balanced position. As in the above case, in the state where the main shaft 10 is positioned in the axial direction at the contact position between the axial bearing surface 21a on one side and the axially opposing surface 11a, the predetermined contact reaction force FR is displaced due to the displacement of the contact reaction force FR of the same magnitude. When the force FR is applied, the amount of displacement is also the same.

Therefore, when the pressing force of the touch probe 2b is equal during the measurement of the reference instrument 4 (see Fig. 7(A)) and the measurement of the workpiece 3 (see Fig. 7(B)), the contact reverse force The FR is also the same, and the displacement amount of the main shaft 10 is also the same. That is, during the measurement of the reference instrument 4, the contact reversal force FR is used to perform zero adjustment in a state where the spindle 10 is displaced by a predetermined amount in the axial direction. The force FR is measured only in a state of being displaced by a predetermined amount, so that the result is not affected by the axial displacement of the spindle 10 and the workpiece 3 can be measured.

Therefore, in the second embodiment, the control unit 130 controls the movement mechanism 110 (see FIG. 1 ) to perform the measurement by the touch sensor 2 with the same pressing force during the measurement of the reference instrument 4 and the measurement of the workpiece 3 .

Furthermore, in the second embodiment, the control unit 130 reduces or blocks the supply pressure to the orifice of the axial bearing surface 21a on the one side in the axial bearing portion 21 in the measurement state P2. Thereby, the axial bearing surface 21a on one side is brought into close contact with the axially opposite surface 11a, and a close contact force can be generated therebetween, so that the movement of the main shaft 10 due to the contact reverse force FR can be effectively suppressed.

In addition, it is preferable that the urging portion 210 is configured to have a larger urging force FF with respect to the workpiece 3 when the contact sensor 2 measures the workpiece 3 in the axial direction. Bounce. Thereby, even when the contact reverse force FR of the contact probe 2b acts on the main shaft 10, the movement of the main shaft 10 can be surely suppressed.

Other structures of the second embodiment are the same as those of the above-described first embodiment.

(Effect of the second embodiment)

In the second embodiment, the following effects can be obtained.

In the second embodiment, similarly to the above-described first embodiment, the non-contact bearing 20 is configured so that when the contact sensor 2 is installed, the spindle 10 is supported in a contact state and can be switched to suppress the movement of the spindle 10 for measurement. In the state P2, when the contact sensor 2 is mounted on the tool holder 40 to measure the workpiece 3, the non-contact bearing 20 is switched to the measurement state P2, and the main shaft can be supported by the non-contact bearing 20 in a contact state 10. Therefore, when the contact reaction force FR of the touch sensor 2 acts on the main shaft 10, the deviation of the main shaft 10 due to the contact reaction force FR can be suppressed compared with the case where the main shaft 10 is kept in a non-contact state.

In the second embodiment, as described above, in the measurement state P2, the main shaft 10 is biased in the axial direction, and the biasing portion 210 for bringing the main shaft 10 into contact with the non-contact bearing 20 is provided. Thereby, it is possible to easily switch to the measurement state P2 by the pusher 210 . In addition, when the main shaft 10 is brought into contact with the non-contact bearing 20 to provide a dedicated urging portion 210, the urging force FF is set according to the magnitude of the contact reaction force FR from the contact sensor 2, whereby the main shaft can be sufficiently suppressed. 10's offset.

The other effects of the second embodiment are the same as those of the first embodiment described above.

(Variation)

In addition, the embodiment disclosed this time is an illustration in all points and should not be restrictive. The scope of the present invention is disclosed by not the description of the above-mentioned embodiment but the scope of the patent application, and includes the meaning equivalent to the scope of the patent application and all the changes (modifications) within the scope.

For example, in the above-described first and second embodiments, the tool holder 40 has a straight-shank type (shank portion 1a ( 2a )) collet member 41 that can directly hold the tool 1 and the touch sensor 2 . , but the present invention is not limited to this. In the present invention, the tool holding portion 40 may not include the collet member 41 . For example, in a spindle device, a configuration in which the collet member is provided on the tool side instead of the tool holder is known.

In FIG. 10, the tool holding part 40 has a holding hole into which the tool holding collet 310 to which the tool 1 is mounted is inserted, and the rotary outer cylinder 320 is screwed and fixed to the main shaft 10 to hold the tool holding collet 310. .

In FIG. 11, the tool holding part 40 has a holding hole into which the tool holding collet 330 to which the tool 1 is fixedly mounted is inserted, and the tool holding collet 330 can be switched by the advance and retreat of the pull rod 340 provided inside the main shaft 10. and release of hold. The tool holding collet 330 has a shank portion 331 having a tapered shape, and when inserted into the tool holding portion 40 , the position of the axis and the direction of the axis are restricted by the tapered surface abutting against. The pull rod 340 is provided instead of the push rod 82 shown in FIG. 2 . As shown in Fig. 11(A), when the draw rod 340 is moved backward, the latch block 341 provided on the draw rod 340 pushes the gripping claw 350 radially outward, and the gripping claw 350 is engaged with the shank 331 on the outer side to hold the gripping claw 350. (Clamping) Tool 1. As shown in Fig. 11(B), when the pull rod 340 is moved forward, the engagement between the handle portion 331 and the clamping claw 350 is released (released) by the pressing of the clamping claw 350 of the release blocking block 341.

The present invention may include the tool holding portion 40 having the configuration shown in the above-mentioned Fig. 10 or Fig. 11 . However, the tool holder 40 has a collet member 41 capable of holding a straight shank (shank 1a ( 2a )) that directly holds the tool 1 and the touch sensor 2 so as to have the tool 1 or touch sensor The tool 2 can not be provided with a point for the tool to hold the collet, and the tool 1 or the contact sensor 2 can be directly held from the collet member 41 mounted on the main shaft 10 in a correctly positioned state, so as to suppress the position of the axis and the deviation of the axis. The offset of the direction is preferably a point that can be fixed with high precision.

In addition, although the said 1st and 2nd embodiment shows the example (the example where the axial bearing part is contacted) with respect to the axial direction (axial direction) of the main shaft 10 with respect to the non-contact bearing 20, this invention is not limited to this. In the present invention, the main shaft 10 can also be brought into contact in the radial direction (radial direction) with respect to the non-contact bearing 20 . That is, a plurality of orifices are provided at equal angular intervals across the entire circumference of the radial bearing portion 22, and the main shaft 10 is supported in a radially non-contact manner by the balance of the static pressure of the compressed air discharged from the respective orifices. . For this reason, the supply of pressure to one or more of the plurality of orifices of the radial bearing portion 22 is blocked, so that the radially opposite surface 12 a of the main shaft 10 can contact the radial direction of the radial bearing portion 22 . Bearing surface 22a. At this time, the movement of the main shaft 10 can be suppressed by increasing the frictional force at the contact point between the radially opposing surface 12a and the radial bearing surface 22a. Furthermore, in combination with the configuration shown in the first or second embodiment, the main shaft 10 may be brought into contact with both the axial bearing portion 21 and the radial bearing portion 22 .

In addition, although the above-mentioned first embodiment shows that the pressure supply to the orifice of the other side thrust bearing surface 21b is blocked, so that the axially opposing surface 11a of the main shaft 10 is brought into contact with the other side thrust bearing surface 21b example, but the present invention is not limited to this. As shown in Fig. 12, it is also possible to block the axial bearing surface on one side. The pressure supply of the orifice 21a causes the axially opposite surface 11a of the main shaft 10 to come into contact with the one-side axial bearing surface 21a.

In addition, although the above-mentioned second embodiment shows an example in which the main shaft 10 is urged toward the one end side (Z1 direction) by the urging portion 210, and the axial bearing surface 21a on one side is brought into contact with the axially opposing surface 11a, the present invention Not limited to this. In the above-described second embodiment, conversely, the main shaft 10 may be biased toward the other end side (Z2 direction) by the biasing portion 210, so that the axially opposing surface 11a of the main shaft 10 is brought into contact with the other side axial bearing. face 21b. At this time, the main shaft 10 and the non-contact bearing 20 are in the same contact state as in the first embodiment described above (see FIG. 5 ).

In addition, although the said 2nd Embodiment shows the example which the push part 210 is comprised by the non-contact pusher of the main shaft 10 by air pressure, this invention is not limited to this. The pushing portion 210 may be configured to push the spindle 10 in direct contact with the spindle 10 by, for example, a pneumatic or hydraulic piston, an electric solenoid, or the like.

In addition, although the above-mentioned first and second embodiments are shown in the measurement state P2, the supply pressure of one of the one side and the other side of the axial bearing portion 21 is made weaker than that of the other, or the supply pressure is blocked. example, but the present invention is not limited to this. In the present invention, for example, a negative pressure source may be provided separately from the positive pressure source in the air pressure source 60, and the negative pressure may be supplied to one of the one side and the other side of the axial bearing portion 21, and the other side may be supplied with negative pressure. Supply positive pressure. Thereby, the main shaft 10 can also be brought into contact with the non-contact bearing 20 .

In addition, although the above-mentioned first and second embodiments show the example of the portal type machining center, the machine tool of the present invention may be a vertical type machining center machine without a portal structure, or the main shaft 10 may be a horizontal machine installed in the horizontal direction. type machining center.

2: touch sensor

10: Spindle

11: Flange

11a: Axial Opposite Surface

12: Shaft

12a: Radially Opposite Surface

20: Non-contact bearings

21: Axial bearing part

21a: Axial bearing surface on one side

21b: Axial bearing surface on the other side

22: Radial bearing part

22a: Radial bearing surface

30: Drive Department

31: Stator

32: Rotor

33: gimbal

40: Tool Holder

50: Shell

51: Access Department

60: Air pressure source

70: Fluid circuit

80: Switching mechanism

81: Actuator

82: putter

100: Spindle device

CL: Clearance

P1: Processing state

Claims (10)

A main shaft device comprising: a main shaft; a non-contact bearing capable of non-contact support to rotate the main shaft around a central axis; a driving part for rotationally driving the main shaft; A tool for machining a workpiece or a contact sensor for measuring a workpiece, wherein the non-contact bearing is configured to be switchable to a measurement state in which the spindle is supported in a contact state to suppress movement of the spindle when the contact sensor is installed . The main shaft device according to claim 1, wherein the non-contact bearing includes an axial bearing portion that supports the main shaft in the axial direction from both sides in the axial direction, and a radial bearing portion that supports the main shaft in a radial direction. In the measurement state, the axial bearing surface of the axial bearing portion is configured to be in axial contact with the axially opposing surface of the main shaft. The main shaft device according to claim 2, wherein the axial bearing portion includes an axial bearing surface on one side that supports the main shaft from one end side, and a shaft on the other side that supports the main shaft from the other end side opposite to the one end side. With regard to the bearing surface, 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 axially opposing surface of the main shaft in the above-mentioned measurement state. The spindle device according to claim 2, wherein the non-contact bearing is a hydrostatic fluid bearing, further comprising a fluid circuit for controlling a supply pressure to the hydrostatic fluid bearing, the fluid circuit being formed at one end of the axial bearing portion Among the side and the other end side, the supply pressure of one of them is made weaker or blocked than that of the other, so that the above-mentioned axial bearing surface and the above-mentioned axially opposite surface are brought into contact. The spindle device according to claim 4, wherein the hydrostatic fluid bearing is a hydrostatic air bearing, and the fluid circuit includes a switching valve for switching the air pressure with respect to any one of the axial bearing portions Supply and block. The main shaft device according to claim 1, further comprising an urging portion for urging the main shaft in the axial direction in the measurement state to bring the main shaft into contact with the non-contact bearing. The spindle device according to claim 1, further comprising: a determination unit that determines whether the touch sensor is attached to the tool holding unit from the tool changing device, and a control unit that determines when the touch sensor is attached to the tool holder. When provided in the said tool holding part, the control which switches the said non-contact bearing to the said measurement state is performed. The spindle device according to claim 1, wherein the tool holding portion includes the straight shank type tool and The collet member of the above-mentioned touch sensor. The spindle device according to claim 1, wherein the drive unit includes an induction motor, and the non-contact bearing is configured to stop the rotation of the spindle by being in contact with the spindle in the measurement state. A machine tool comprising: the spindle device according to any one of Claims 1 to 9; a moving mechanism for moving the spindle device and a workpiece relatively; The above-mentioned spindle of the spindle unit is disassembled.

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