JP2000263376A - Static pressure magnetic compound bearing spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the load acting to a main spindle and tool or the damage state of the tool without providing a load measuring device to the outside and ensure the high speed, high accuracy and high rigidity of the main spindle. SOLUTION: The means 15 to 18 for detecting the current supplied to the electromagnets of static pressure magnetic compound bearings 6 to 9 are built in a spindle controller 3. The machining state grasping means 19 for grasping the machining state such as tool damage state from the current detection value is provided so as to convert the static load of a main spindle 4 from the current detection value itself, when the control means 43 of an exciting current is constituted by an integration circuit or proportional integration circuit. The machining state grasping means 19 can be the thing coverting the static load by entering the current detection value in a smooth circuit or the thing grasping the machining state from the amplitude of each frequency component by frequency analyzing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic magnetic composite bearing spindle device provided in a high-speed cutting device, a grinding device, or the like.

[0002]

2. Description of the Related Art Recently, high-efficiency and high-precision processing such as die processing has been attracting attention.
In order to realize such machining, a spindle device that can rotate at high speed, has high rotational accuracy, and has high static rigidity and dynamic rigidity is required.
Processing under optimal processing conditions is required. In response to such demands, a hybrid type non-contact bearing in which a hydrostatic gas bearing and a magnetic bearing are combined has been proposed (Japanese Patent Application No. Hei.
-097550). According to this, it is possible to provide a compact bearing that utilizes the characteristics of both bearings, that is, excellent dynamic rigidity and rotational accuracy of the hydrostatic gas bearing, and excellent static rigidity of the magnetic bearing. The measurement of the processing load of the machine tool for detecting the processing state employs a method of estimating the load at the time of processing from the measured value of the motor output for rotating the spindle.

However, such a method of estimating a load at the time of machining from a measured value of a motor output requires a dedicated measuring device for detecting a machining state, and has a problem that a system cost is increased. Further, in the method of detecting the machining state from the measured value of the motor output, the machining state related to the rotation frequency of the spindle cannot be detected. Conventionally, there has been proposed a spindle device that supports a main shaft with a magnetic bearing and detects a machining state from an excitation current of the magnetic bearing.
However, it is difficult to obtain high-speed rotation accuracy and high dynamic rigidity by supporting only with the magnetic bearing. Further, in the above-described apparatus for detecting a machining state from an excitation current of a magnetic bearing, an attempt has been made to detect a machining state related to frequency by providing a frequency filter. However, if an attempt is made to detect a large number of frequency bands, a large number of frequency filters are required, which complicates the configuration and increases the cost.

An object of the present invention is to provide a load measuring device externally while being capable of high-speed rotation, having high rotational accuracy, high static rigidity and dynamic rigidity, and enabling detection of a machining state during machining. It is an object of the present invention to provide a hydrostatic magnetic composite bearing spindle device which does not require the above and can reduce the cost. Another object of the present invention is to enable detection of a static load on a spindle. Still another object of the present invention is to enable a simple configuration to detect a machining state related to a rotation frequency of a spindle. Still another object of the present invention is to make it possible to externally manage the detected value of the load on the spindle. Still another object of the present invention is to make it possible to remotely detect the detected value of the load on the spindle.

[0005]

The structure of the present invention will be described with reference to FIG. 1 corresponding to an embodiment. In the first hydrostatic magnetic composite bearing spindle device (1) according to the present invention, a spindle (4) to which a tool (11) is attached at the tip is composed of a hydrostatic gas bearing (6A to 9A) and a magnetic bearing (6B to 9B). A spindle drive source (10) supported by a hydrostatic magnetic composite bearing (6 to 9) in which the magnetic bearings (6B to 9) are combined, and a spindle drive source (10) for rotating the main shaft (4).
Current detecting means (15 to 18) for detecting the exciting current of B)
And a machining state grasping means (19) for grasping the machining state by the tool (11) from the current detection values of the current detecting means (15 to 18). According to this configuration, the magnetic bearing (6) in the hydrostatic composite bearing (6 to 9) is used.
From the detected current values of the excitation currents in B to 9B), the machining state can be grasped by the machining state grasping means (19). That is,
When the main shaft (4) is displaced in a radial direction or the like by a load acting on the tool (11) during machining, the exciting current of the magnetic bearings (6B to 9B) is changed so as to restore the displacement. To 9B) depending on the control function. Therefore, a machining state such as tool wear, tool damage, machining failure, and the like can be grasped from the excitation current. Since the machining state grasping means (19) is provided in this way, the high performance of the hydrostatic magnetic composite bearings (6 to 9), that is, high speed rotation is possible.
Combined with the functions of high rotational accuracy, high static rigidity and dynamic rigidity, it is possible to perform processing under optimum processing conditions while detecting the processing state.
Higher efficiency and higher precision processing can be performed by taking advantage of the features described above. Moreover, the detectors need only be provided with current detecting means (15 to 18) for exciting current of the magnetic bearings (6B to 9B), and it is not necessary to provide an external load measuring device.
In addition, compared to a method for detecting the motor current, a simpler method is required, and the cost can be reduced.

In the present invention, the current detecting means (15 to
18) may be provided in a spindle controller (3) that controls the hydrostatic magnetic composite bearings (6 to 9). As described above, by providing the current detecting means (15 to 18) in the spindle controller (3), it becomes compact and easy to handle. In the present invention, the processing state grasping means (19) includes a current detecting means (15 to 15).
18) a current smoothing unit for smoothing the detected current value, and a machining state grasping unit for converting the static load of the spindle from the smoothed value output of the current smoothing unit and grasping the machining state from the static load conversion result. It is good. As described above, by grasping the machining state from the static load conversion result, the machining state required for control can be grasped easily and accurately without being affected by load fluctuation or disturbance occurring in a very short time.

According to a second hydrostatic magnetic composite bearing spindle device of the present invention, a main shaft (4) to which a tool (11) is attached at the tip is composed of a hydrostatic gas bearing (6A to 9A) and a magnetic bearing (6A).
B-9B) and a hydrostatic magnetic composite bearing (6-
9) A spindle device provided with a spindle drive source (10) supported by 9) and rotating the spindle (4), wherein the displacement detection means (28, 3) detects displacement of the spindle (4).
8) and machining state grasping means (19) for grasping the machining state by the tool (11) from the displacement detection values of the displacement detecting means (28, 38). When the spindle (4) is displaced by a load acting on the tool (11) during machining, the displacement is detected by the displacement detecting means (28, 38). Therefore, the machining state can be grasped from the displacement detection value. Therefore, the provision of the above-mentioned machining state grasping means (19) is combined with the functions of the hydrostatic magnetic composite bearings (6 to 9) capable of high-speed rotation, having high rotation accuracy, high static rigidity and dynamic rigidity. In addition, it is possible to perform machining under the optimal machining conditions while detecting the machining state, and it is possible to perform machining with higher efficiency and higher accuracy by utilizing the features of the hydrostatic composite bearings (6 to 9). Moreover, the displacement detecting means (28, 3
8) is a detecting means generally provided in the magnetic bearings (6B to 9B) for controlling the magnetic bearings (6B to 9B), so that the machining state can be grasped without providing a dedicated detecting means, and Processing accuracy can be improved at low cost.

In the first and second hydrostatic magnetic composite bearing spindle devices of the present invention, the machining state grasping means (1)
9) a frequency analyzing section for frequency-analyzing the output of the current detecting means (15 to 18) or the displacement detecting means (28, 38); and an amplitude of each frequency component output from the frequency analyzing section during processing. And a machining state grasping unit for grasping the machining state from the above. The load acting on the tool is expressed as tool vibration based on the natural vibration of the tool, the workpiece, and the processing machine, or the rotational speed of the spindle. The machining state, such as tool damage, depends on the type of tool damage, machining failure, etc. Show a characteristic tendency. Therefore, by providing a frequency analysis unit and a machining state grasping unit that grasps the machining state from the amplitude of each frequency component during machining, a highly accurate machining state that cannot be observed by detecting the averaged load of each frequency component Can be detected. Further, since the frequency analysis is performed, it is possible to analyze a large number of frequency bands with a simpler configuration than a frequency filter.

In the present invention, the spindle drive source (10) may be built in a housing (10) in which the hydrostatic magnetic composite bearings (6 to 9) are installed.
In such a spindle device with a built-in spindle drive source, the effects of the above-described configurations of the present invention are effectively exhibited.

In each of the spindle devices of the present invention, a spindle controller (3) for controlling the hydrostatic composite bearings (6 to 9) and the current detecting means (15 to 1).
8) The current detection value, the smoothed value output of the current smoothing unit, and the amplitude value of each frequency component output by the frequency analysis unit are output to the outside of the spindle controller (3). Output means (44) may be provided. By providing the external output means (44), the load on the tool (11) can be monitored outside the spindle controller (1). For example, the numerical controller (1) of the processing device (13) equipped with the spindle device (1)
4) The load of the tool (11) can be monitored by an independent information processing means or the like, and the machining state can be grasped. The spindle device for remotely grasping a machining state according to the present invention includes a spindle device (1) having any one of the above-described configurations according to the present invention, and an information processing means (91) located at a remote location from the spindle device (1).
And a processing state grasping means (1) of the spindle device (1).
9), any of the current detection values of the current detection means (15 to 18), the smoothed value output of the current smoothing unit, and the amplitude value of each frequency component output by the frequency analysis unit.
Information processing means (91) at the remote place via a communication line (65)
The information processing means (91) may have a function of performing predetermined processing on the communicated information. Thus, the communication line (6
By providing the communication function according to 5), it is possible to grasp the load of the tool and the processing state at a remote place, and it is possible to centrally manage a large number of spindle devices and processing machines at a remote place.

[0011]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a conceptual configuration of a hydrostatic magnetic composite bearing spindle device according to this embodiment. First, the outline will be described. This spindle device 1
It is mainly composed of a spindle device main body 2 and a spindle controller 3. The spindle device main body 2 includes a main shaft 4
Are supported by a plurality of radial-type hydrostatic composite bearings 6 and 7 installed in the housing 5 and axial hydrostatic magnetic composite bearings 8 and 9, and a spindle drive source 10 is provided. Each of the hydrostatic magnetic composite bearings 6 to 9 is a combination of the hydrostatic gas bearings 6A to 9A and the magnetic bearings 6B to 9B, and is controlled by the spindle controller 3. Spindle 4
Has a chuck 12 at its tip for holding a tool 11. The processing device 13 equipped with this spindle device 1
It is controlled by the numerical controller 14. The spindle controller 3 includes a magnetic bearing 6 constituting the hydrostatic magnetic composite bearings 6 to 9.
Current detecting means 15 to 18 for detecting exciting currents B to 9B
And a machining state grasping means 19 for grasping the machining state of the tool 11 from the current detection values of the current detecting means 15 to 18. Further, the spindle controller 3 is provided with an external command response on / off means 20 for turning on / off the excitation of the magnetic bearings 6B to 9B by an external command sent from the numerical controller 14 or the like.

FIGS. 2 to 5 show the spindle device main body 2.
It will be described together. The spindle device 1 includes a processing device 1
3. A built-in motor type spindle device according to item 3,
The spindle drive source 10 is installed in the housing 5 in which the bearings 6 to 9 are installed. The spindle drive source 10 including the motor includes a rotor 21 provided integrally with the main shaft 4 and a stator 22 provided in the housing 5. The housing 5 is formed in a substantially cylindrical shape. The spindle drive source 10 is not a built-in type,
It may be provided outside the housing 5 to transmit rotation to the main shaft 4 via a transmission mechanism. In this example, the arrangement of the bearings 6 to 9 and the spindle drive source 10 is such that the front part (tool side part) and the rear part of the main shaft 4 are supported by radial type hydrostatic composite bearings 6 and 7, and the intermediate part is axial. Supported by a pair of hydrostatic magnetic bearings 8 and 9 and a spindle drive source 10 at the rear end.
Are arranged. Instead of the above arrangement, the spindle drive source 10 may be arranged between the radial bearings 6 and 7, and the axial bearings 8 and 9 may be arranged at an arbitrary position on the main shaft 4. The axial type bearings 8 and 9 may be non-contact bearings, and a single magnetic bearing or a static pressure gas bearing may be used instead of the hydrostatic / magnetic composite bearing.

Radial type hydrostatic magnetic composite bearings 6, 7
3 have the same configuration. FIG. 3 shows a cross section of one of the bearings 6, and FIG. The hydrostatic and magnetic composite bearings 6 and 7 are each a composite of the hydrostatic gas bearings 6A and 7A and the magnetic bearings 6B and 7B. The term "combination" as used in this specification means that both types of bearings of a static pressure type and a magnetic type are combined so as to generate a common portion. For example, a common portion (a radial bearing) is formed between a static pressure gas bearing surface and a magnetic bearing surface. In this case, an axially overlapping portion may be generated, or at least a part of parts may be shared by both types of bearings.

In this embodiment, as shown in FIG. 4, the throttles 24a of the hydrostatic gas bearings 6A and 7A are provided in the core 23 of the electromagnet of the magnetic bearings 6B and 7B, so that the bearing components can be used in common. Part of the bearing surface is configured to overlap in the axial direction. The core 23 includes a pair of main cores 23a, 23a separated in the axial direction, a connection core 23b connecting the main cores 23a, 23a, and both main cores 23a, 23a.
And a pair of extending portions 23c, 23c extending from the main shaft side end to form a C-shaped vertical section. Main core part 23a
The inner diameter side surface of the extension portion 23c is a cylindrical surface forming a predetermined magnetic gap with the main shaft 4. Magnetic bearing 6B, 7
B is a structure in which the coil 25 is wound around the connecting core portion 23b of the core 23. The coil 25 is embedded in a non-magnetic body 26 such as a resin material.

The static pressure gas bearings 6A and 7A are formed on the inner diameter side surfaces of the core 23 and the non-magnetic material 26 and form a bearing gap d between the main shaft 4 and the static pressure bearing surfaces 6Aa and 7Aa. An aperture 24a is provided on each of the main cores 23a, 23a and opens on the hydrostatic bearing surfaces 6Aa, 7Aa. The throttles 24a are provided at the ends of the air supply holes 24 opened on the outer diameter side surfaces of the main core portions 23a. As shown in a stepped cross section in FIG. 3, the cores 23 are arranged at a plurality of locations (four locations in the example in the figure) in the circumferential direction around the main shaft 4 and fixed to the housing 5. The gap between the circumferentially adjacent cores 23 is filled with a non-magnetic material 27 such as a resin material. The non-magnetic body 27 is formed around the non-magnetic body 26 around the coil 25.
(FIG. 4).

The magnetic bearings 6B and 7B are composed of a main shaft 4 and a core 23.
And a displacement detecting means 28 for detecting the displacement of the magnetic gap between them. The displacement detecting means 28 may directly detect the displacement amount, but in this example, by detecting the static pressure in the static pressure bearing gap d, the detected pressure value is converted into the displacement amount. To detect the displacement of the magnetic gap. More specifically, the displacement detecting means 28 is composed of a pressure detection air passage 28a having a distal end opened in the static pressure bearing gap d, and a sensor 28b communicating with the air passage 28a.
The sensor 28b is disposed at a position axially away from the core 23 as shown in FIG. The air passage 28a is formed by a fine hole or a pipe, and the core 2
An opening is provided at the portion of the non-magnetic member 26 between the third extending portions 23c. In FIG. 3, the opening positions of the throttle 24a and the ventilation path 28a are shifted in the circumferential direction for the sake of clarity, but they are actually at the same position in the circumferential direction.

FIG. 5 is an enlarged view of the axial type hydrostatic composite bearings 8 and 9. The pair of bearings 8, 9 are opposed to both surfaces of a flange 4 a provided on the
And constitute one double-sided axial type hydrostatic gas bearing 30. The hydrostatic composite bearings 8 and 9 on both sides have the same configuration. These hydrostatic magnetic composite bearings 8 and 9 are respectively composed of hydrostatic gas bearings 8A and 9
A and the magnetic bearings 8B and 9B are combined.
In this embodiment, the throttles 34a of the hydrostatic gas bearings 8A and 9A are provided on the electromagnet cores 33 of the magnetic bearings 8B and 9B, so that the bearing components are shared and a part of the bearing surface overlaps in the axial direction. It is like that. The core 33 has a C-shaped longitudinal section so that an opening 33d is formed on the surface facing the spindle flange 4a, and the coil 35 is accommodated therein. The opening 33d is filled with a non-magnetic material. The core 33 has an assembly configuration of an inner core portion 33a and an outer core portion 33b having an L-shaped cross section in the illustrated example, but may be an integral structure. The spacer 29 is adjacent to the core 33 in the axial direction.

Axial type hydrostatic gas bearings 8A, 9A
Are hydrostatic bearing surfaces 8Aa, 9A formed on the side surface of the core 33 and forming a bearing gap d2 with the spindle flange 4a.
a, and hydrostatic bearing surfaces 8Aa, 9Aa provided on the core 33.
And a stop 34a which is open to the outside. The aperture 34a is
It is provided at the tip of an air supply hole 34 opened on the outer diameter side surface of the core 33.

The axial type magnetic bearings 8B and 9B have displacement detecting means 38 for detecting the displacement of the magnetic gap between the spindle flange 4a and the core 33. The displacement detecting means 38 may directly detect the displacement amount, but in this example, by detecting the static pressure in the static pressure bearing gap d2, the detected pressure value is converted into the displacement amount. To detect the displacement of the magnetic gap. More specifically, the displacement detection means 38 includes a pressure detection air passage 38a having a distal end opened in the static pressure bearing gap d2, and a sensor 38b (FIG. 2) communicating with the air passage 38a.

In the static pressure gas bearings 6A to 9A of each of the static pressure magnetic composite bearings 6 to 9, compressed air or other compressed air or other air is supplied to the gas supply holes 24 and 34 from the gas supply inlet 40a of the gas supply hole 40 provided in the housing 5. Is supplied.

The control system will be described. As shown in FIG. 1, the spindle controller 3 has a power supply 41, an electromagnet power circuit 42, and a control means 43 in the controller basic unit 3a. The electromagnet power circuit 42
The current supplied from the power supply 41 is supplied to the magnetic bearings 6B to 9 of the respective hydrostatic magnetic composite bearings 6 to 9 under the control of the control means 43.
This is a means for giving an exciting current to B, and is constituted by a current amplifier circuit or the like. The control means 43 controls each static pressure magnetic composite bearing 6
9 so that the displacement of the main shaft 4 is restored according to the detection values of the displacement detecting means 28 and 38 in the magnetic bearings 6B to
This is a means for controlling the exciting current of 9B. Control means 43
Specifically, for example, an excitation current control command is given in accordance with the result obtained by calculating the detection values of the displacement detection means 28 and 38 by an integration circuit or a proportional integration circuit.

In this embodiment, the spindle controller 3 having this basic configuration is provided with the above-mentioned current detecting means 15-1.
8, the machining state grasping means 19 and the external command response on / off means 20 are provided, and the external output means 44 is provided,
And an excitation on / off command generating means 45 provided to the numerical controller 14.
And processing state correspondence processing means 46. For example, a current detector is used for the current detection units 15 to 18. As shown in FIG. 6, the numerical control device 14 has a numerical control function unit 14a and a programmable controller function unit 14b, and the numerical control function unit 14a decodes the machining program 50 to read each axis of the machining device body 13a. And the sequence command described in the machining program 50 is transferred to the programmable controller function unit 14b. The programmable controller function unit 14b is configured to execute the processing device body 13a
The programmable controller function unit 14b is provided with the excitation on / off command generation unit 45 and the processing state correspondence processing unit 46.

FIG. 8 shows a basic conceptual configuration of the processing state grasping means 19. The machining state grasping means 19 is a means for grasping the machining state by the tool 11 from the current detection values of the current detecting means 15 to 18 as described above, and the grasping result is sent to the machining state correspondence processing means 46 of the numerical controller 14. Sent.
This grasp result may be the current detection value as it is,
It may be a comparison result obtained by comparing the current detection value with a set value, a value obtained by performing a predetermined calculation process from the current detection value, and a result obtained by comparing the calculation process with the set value. Is also good. If the control means 43 controls the exciting current in accordance with the values calculated by the integration circuits or the proportional integration circuits based on the detection values of the displacement detection means 28 and 38 as described above, The static load of the spindle 4 is converted from the detected value itself. Further, the processing state grasping means 19 includes the current detecting means 15 to 1.
8 is to output the results of grasping the machining state individually with respect to the detected current values of 8;
8, the current detection means 15 to 18 may output a grasping result of the machining state which comprehensively determines the detected current value.
Of these, the machining state may be grasped only by one or more specific detected current values.

FIG. 9 shows a specific example of the processing state grasping means 19. In this example, the machining state grasping means 19 calculates the current detection value of each of the current detecting
A current smoothing unit 19a for smoothing each of the currents;
And a machining state grasping unit 19b for transforming the static load of the spindle from the smoothed value output of 9a and grasping the machining state from the static load conversion result. Processing state grasping part 1
9b specifically, for example, compares the converted spindle static load with a set value, and outputs an abnormality when the set spindle load exceeds the set value. FIG. 12 shows a processing state grasping unit 19b.
1 shows an example of the processing performed in step (a). The static load of the main shaft 4a becomes a constant value as shown by a curve a when constant processing is continued. If tool wear increases or tool damage occurs,
It changes as shown by curves b and c. Therefore, an upper limit value and a lower limit value which are allowable as an appropriate load are determined as set values. When the upper limit value and the lower limit value are within the range (shaded area), the tool is normal and deviates from this range as shown by curves b and c. In this case, an abnormal signal of the tool abnormality is output as a result of grasping the machining state. In this specification, “converting a smoothed value output to a spindle static load” refers to a case where a smoothed value output is converted to a unit of load and a value at which a smoothed value output is converted to a value which is easily compared with a set value as a load. Includes both conversions.

FIG. 10 shows another specific example of the processing state grasping means 19. In this example, the machining state grasping means 19 calculates the current detection value of each of the current detecting
It has a frequency analysis unit 19c for frequency analysis and a processing state grasping unit 19d for grasping the machining state from the amplitude of each frequency component at the time of processing output from the frequency analysis unit 19c. FIG. 13 shows an example of a process performed by the processing state grasping unit 19c. When the constant processing is continued, the frequency analysis result of the detected current value becomes a substantially constant waveform having different amplitudes of the respective frequency components as shown by a curve d. Therefore, the set values m1, m2,.
Is set, and if the amplitude value of any of the frequency components exceeds the set value m2 of the corresponding frequency band, for example, as indicated by a curve portion e indicated by a broken line, it is determined that the tool is abnormal.

The machining state grasping means 19 is to grasp the machining state from the current detection values of the current detecting means 15 to 18 in each of the above specific examples.
May be used to grasp the machining state from the detected values of the displacement detecting means 28 and 38. For example, processing state grasping means 1
Reference numeral 9 denotes a frequency analysis unit 19e for frequency-analyzing the outputs of the displacement sensor amplifiers of the displacement detection means 28 and 38, and the amplitude of each frequency component output from the frequency analysis unit 19e during machining, as shown in FIG. A machining state grasping unit 19f for grasping the machining state may be provided.

As shown in FIG. 1, the machining state grasping means 19 of each of the above-described components has a setting section 19g, which is used to output a grasping result of the machining state in comparison with a set value. The part 19g is used. The setting unit 19g is set such that various setting values can be changed or a plurality of preset setting values can be selected according to a command from the numerical controller 14 or other means. For example, when processing with different loads, such as roughing and finishing, is performed during operation of the spindle device, it is necessary to judge the acceptability of the tool with a set value according to the load. The setting unit 19g is capable of changing such a set value, and detects a signal accompanying a change in processing of the numerical controller 14 and changes the set value.

The external output means 44 comprises current detection means 15 to
18, the progress and results grasped by the machining state grasping means, for example, the smoothed value output of the current smoothing section 19 a (FIG. 9), the amplitude value of each frequency component outputted by the frequency analysis sections 19 c and 19 e, etc. Is output to the outside of the spindle controller 3. The numerical control device 14 may be configured such that the processing state is input via the external output means 44, and the output of the external output means 44 is
4 may be input to another information processing means, for example, an information processing means for statistical processing of the processing state. The processing state correspondence processing means 46 provided in the numerical control device 14 includes:
In accordance with the output of the grasping result of the machining state grasping means 19, the machining apparatus 13 performs a predetermined process for a tool failure or the like, such as generation of an alarm or forced stop of the machining apparatus.

The external command response on / off means 20 is means for turning on / off the excitation of the magnetic bearings 6B to 9B in the hydrostatic magnetic composite bearings 6 to 9 according to a command external to the spindle controller 3. On / off of the excitation by the external command response on / off means 20 may be performed for all of the magnetic bearings 6B to 9B, or may be performed for only a specific one. In the example of FIG. 1, the external command response on / off means 20 is connected to the magnetic bearing 6B from the electromagnet power circuit 42.
9B is provided with a switch responsive to a control signal in each electric circuit portion. The external command response on / off means 20 includes a power supply 41 as shown in FIG.
15 may be provided between the control means 43 and the electromagnet power circuit 42, and the current becomes zero for the electromagnet power circuit 42, as shown in FIG. A command may be given.

The excitation on / off command generating means 45 of the numerical controller 14 gives an on / off command to the external command response on / off means 20 in accordance with a command of the machining program 50 as the machining by the numerical control progresses. In this case, the excitation on / off command generating means 45 is configured, for example, by a predetermined command generated in the numerical controller 14 when the predetermined command of the machining program 50 is decoded by the numerical controller 14 or executed. , An excitation on / off command is generated. The on / off command to the external command response on / off means 20 may be issued from an information processing means such as a computer other than the numerical controller 14.

FIG. 7 shows an example of control when machining is performed by turning on / off the external command response on / off means 20. This example is an example applied when there is a finishing machining command after a rough machining command as in a machining program 50 shown in FIG. First, the excitation is turned on by the rough machining command (S1) (S1).
After 2), the spindle 4 is started (S3). In this state, the hydrostatic / magnetic composite bearings 6 to 9 support the main shaft 4 with both static pressure and magnetic force. Until the finish processing command is issued, the excitation is maintained as it is (S4). When there is a finish processing command, the excitation is turned off (S5), and the hydrostatic magnetic composite bearings 6 to 9 are turned off.
Are supported only by the static pressure gas bearings 6A to 9A. When there is a predetermined command such as the end of machining or rough machining of another part (S6),
The excitation is turned on (S7), and the spindle 4 is supported by both static pressure and magnetic force.

As described above, the magnetic bearings 6B to 9
By turning off B and using the magnetic bearings 6B to 9B at the time of finish machining, high efficiency can be achieved at the time of rough machining, and high accuracy can be achieved at the time of finish machining, and high efficiency and high precision machining can be realized.

FIG. 16 shows an example of a processing device 13 equipped with the hydrostatic magnetic composite bearing spindle device 1. This example is an example applied to a mold processing apparatus. Spindle device 1
The spindle device main body 2 is set up and down on a base 52 via a guide 53 above a table device 51, and is driven up and down by a spindle lifting device 54. As shown in FIG. 17, the table device 51 is provided with a table 55 on which a work W is placed so as to be movable in two horizontal axes (X and Y directions) orthogonal to each other. , 57 are moved forward and backward. The table 55 includes an upper table 55 movably in the X-axis direction on a lower table 55a movable in the Y-axis direction.
b has a two-stage structure. The table driving devices 56 and 57 and the spindle elevating device 54 of each axis are respectively constituted by a ball screw and a servomotor.

Next, the communication system will be described. As shown in FIG. 1, the spindle device 1 includes a remote information processing unit 91 and a communication line 65 such as a telephone line network in the spindle controller 3 or separately from the spindle controller 3.
And a communication means 60 for communicating with the user. Communication means 60
May also serve as the external output means 44, and may be provided in the numerical control device 14, information processing means (not shown) serving as a higher-level control computer of the numerical control device 14, and the like. Is also good. The communication unit 60 includes an output of the processing state grasping unit 19 of the spindle device 1, a current detection value of the current detection units 15 to 18, a smoothed value output of the current smoothing unit 19a (FIG. 9), and frequency analysis units 19c and 19e.
Any of the amplitude values of each frequency component output in (FIGS. 10 and 11) can be communicated. Further, the remote information processing means 91 has a function of performing a predetermined process on the information communicated from the communication means 60. The predetermined processing includes, for example, statistical processing of a processing state, generation of a command for controlling the spindle controller 3 or the numerical controller 14, and the like. Further, the information processing means 91 in this remote place
Has a function of giving an on / off command to the external command response on / off means 20 of the spindle controller 3. The transmission of the on / off command from the information processing means 91 to the external command response on / off means 20 is performed via the numerical control device 14 or information processing means (not shown) serving as a higher-level control computer of the numerical control device 14. Is also good.

FIG. 18 shows a development example of the communication system of the spindle device 1 of FIG. 1 and the processing device 13 equipped with the spindle device 1. A plurality of other processing devices 72 are installed in the business establishment 71 in which the processing device 13 is installed, and these processing devices 13 and 72 are used alone or in a plurality of common information processing means 73 and 74. It is connected. These information processing means 73 and 74 constitute a local area network 89 together with network components such as the web server 80, the fiber wall 81, and the rotor 82. The local area network 89 is connected via the communication line 65 to the remote information processing means 91 installed in the local area networks of the different offices 83 and 84 via the communication device 86 via the Internet 90. I have. The processing device 13 is basically configured such that the numerical control device 14 is connected to the information processing means 73 and connected to a communication line in the local area network 89 via the information processing means 73. , Together with or separately from this, the numerical controller 14
Communication means 60 provided in the spindle controller 3
, A communication system connected directly to a communication line in the local area network 89 may be provided.

[0036]

According to the present invention, a hydrostatic magnetic composite bearing spindle device uses a hydrostatic magnetic composite bearing for supporting a main shaft, and current detecting means for detecting an exciting current of the magnetic bearing, and current detection of the current detecting means. Since it is equipped with a machining state grasping means for grasping the machining state by the tool from the values, the machining state such as the load acting on the spindle and the tool or the damage state of the tool can be achieved without providing an external load measuring device. Can grasp. As a result, the high-speed rotation of the hydrostatic magnetic composite bearing is possible, making use of the features of high rotation accuracy, high static rigidity and dynamic rigidity. Processing can be performed. In the case where a current smoothing unit for smoothing the current detection value of the current detection means is provided, it is possible to detect a static load on the spindle. When a displacement detecting means for detecting the displacement of the main spindle and a machining state grasping means for grasping a machining state by the tool from a displacement detection value of the displacement detecting means are provided, the machining state is not provided without providing dedicated sensors. Can be grasped. In addition, when a frequency analysis unit that analyzes the frequency of the output of the current detection unit or the displacement detection unit is provided, it is possible to detect a machining state related to the rotation frequency of the spindle with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a conceptual configuration of a hydrostatic composite bearing spindle device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of the spindle device main body.

FIG. 3 is a cross-sectional front view of the spindle device main body.

FIG. 4 is an enlarged sectional view of a radial type hydrostatic composite bearing.

FIG. 5 is an enlarged sectional view of an axial type hydrostatic magnetic bearing.

FIG. 6 is a block diagram illustrating a conceptual configuration of a numerical control device.

FIG. 7 is a flowchart showing an example of an excitation on / off control of a magnetic bearing in a hydrostatic magnetic composite bearing.

FIG. 8 is a block diagram showing a basic configuration of a processing state grasping means.

FIG. 9 is a block diagram showing a modification of the processing state grasping means.

FIG. 10 is a block diagram showing another modification of the processing state grasping means.

FIG. 11 is a block diagram showing still another modification of the processing state grasping means.

FIG. 12 is a graph showing an example of grasping a machining state by current smoothing.

FIG. 13 is a graph showing an example of grasping a machining state by frequency analysis.

FIG. 14 is a block diagram of a spindle controller in which the arrangement of external command response on / off means is different.

FIG. 15 is a block diagram of a spindle controller in which the arrangement of external command response on / off means is further different.

FIG. 16 is a front view of a processing apparatus equipped with the hydrostatic composite bearing spindle device.

FIG. 17 is a plan view of a table portion of the processing apparatus.

FIG. 18 is an explanatory diagram showing a conceptual configuration of a hydrostatic magnetic composite bearing spindle device that can be remotely operated or remotely monitored.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Spindle device 19a ... Current smoothing part 2 ... Spindle device main body 19b, 19d, 19f
... Processing state grasping part 3 ... Spindle controller 19c, 19e ... Frequency analysis part 4 ... Spindle 20 ... External command response on / off means 5 ... Housing 28, 38 ... Displacement detecting means 6-9 ... Static magnetic composite bearing 44 ... External output means 6A to 9A: Static pressure gas bearing 45: Excitation on / off command generating means 6B to 9B: Magnetic bearing 46: Processing state correspondence processing means 10: Spindle drive source 60: Communication means 14: Numerical control device 65: Communication line 15 to 18: Current detecting means 91 ... remote information processing means 19 ... processing state grasping means

Continuation of the front page F term (reference) 3C001 KA06 KB02 3C029 CC03 3C045 FD16 3J102 AA01 AA02 BA03 BA19 CA09 CA19 DA02 DA03 DA09 DB37 EA02 EA06 EA13 GA07

Claims (8)

[Claims] 1. A spindle device having a spindle on which a tool is mounted at a tip end is supported by a hydrostatic / magnetic composite bearing in which a hydrostatic gas bearing and a magnetic bearing are combined, and a spindle drive source for rotating the spindle is provided. A hydrostatic magnetic composite bearing main spindle device comprising: a current detecting means for detecting an exciting current of the magnetic bearing; and a processing state grasping means for grasping a machining state by the tool from a current detection value of the current detecting means. 2. The hydrostatic magnetic composite bearing spindle device according to claim 1, wherein said current detecting means is provided in a spindle controller for controlling said hydrostatic magnetic composite bearing. 3. The processing state grasping means includes: a current smoothing section for smoothing a current detection value of the current detecting means; and a static load of the main shaft converted from a smoothed value output of the current smoothing section. The hydrostatic magnetic composite bearing spindle device according to claim 1 or 2, further comprising a machining state grasping unit for grasping a machining state from a result. 4. A spindle device in which a spindle on which a tool is mounted at a tip is supported by a hydrostatic and magnetic composite bearing in which a hydrostatic gas bearing and a magnetic bearing are combined, and a spindle drive source for rotating the spindle is provided. A hydrostatic magnetic composite bearing spindle device comprising: a displacement detecting means for detecting a displacement of the main shaft; and a machining state grasping means for grasping a machining state by the tool from a displacement detected value of the displacement detecting means. 5. The processing state grasping means comprises: a frequency analyzing section for frequency-analyzing an output of the current detecting means or the displacement detecting means; and a processing means for processing the output from the frequency analyzing section based on an amplitude of each frequency component at the time of processing. The hydrostatic magnetic composite bearing spindle device according to claim 1, further comprising a machining state grasping section for grasping a state. 6. The hydrostatic magnetic composite bearing spindle device according to claim 1, wherein the spindle drive source is a motor built in a housing in which the hydrostatic magnetic composite bearing is installed. 7. A spindle controller for controlling the hydrostatic magnetic composite bearing, a current detection value of the current detection means,
An external output means for outputting a smoothed value output of the current smoothing unit and any one of amplitude values of respective frequency components output by the frequency analysis unit to outside of the spindle controller. The hydrostatic magnetic composite bearing spindle device according to claim 5. 8. An output of the hydrostatic magnetic composite bearing spindle device according to claim 1, an information processing means remote from the spindle device, and a processing state grasping means of the spindle device. Any one of the current detection value of the current detection unit, the smoothed value output of the current smoothing unit, and the amplitude value of each frequency component output by the frequency analysis unit to the remote information processing unit via a communication line. And a communication means for communicating, wherein the information processing means has a function of performing predetermined processing on the communicated information.