WO2002075904A1

WO2002075904A1 - Method and apparatus for detecting vacuum position in vacuum motor

Info

Publication number: WO2002075904A1
Application number: PCT/JP2001/008077
Authority: WO
Inventors: Yuji Arinaga; Koji Suzuki; Masamichi Inenaga; Tadataka Noguchi; Takayuki Nakamura
Original assignee: Kabushiki Kaisha Yaskawa Denki
Priority date: 2001-03-16
Filing date: 2001-09-17
Publication date: 2002-09-26
Also published as: JP2002281725A; JP3812807B2

Abstract

A vacuum position detecting method in vacuum motor in which the degree of freedom can be increased in the design of motor without sacrifice in reliability, and a thin lightweight vacuum position detector which can detect the absolute angle. In a method for detecting a position by providing a rotor (3) rotatable through a bearing (6) in a motor case having a stator (1) with a detector rotor disposed on the vacuum side, the detector rotor comprises a planar slit disc (5) made by making a plurality of slits in the plane of a magnetic steel plate and a slit disc base for securing it, a magnetic sensor head (2) comprising an MR magnet and a permanent magnet resin sealed in a sensor case is disposed on the stator (1) side oppositely to the slit disc (5), and the magnetic sensor head (2) detects presence of the slit made in the surface of the slit disc (5).

Description

Vacuum position detection method and vacuum position detection device for vacuum motor

[Technical field]

The present invention relates to a vacuum position detecting method and a vacuum position detecting device in a vacuum motor for detecting the position and speed of a servomotor used in a vacuum such as a semiconductor manufacturing apparatus.

[Background technology]

A vacuum motor is disclosed in Japanese Patent Application Laid-Open No. Hei 11-356650. FIG. 11 is a cross-sectional view of a vacuum position detector showing a configuration of a conventional example. In FIG. 11, a magnetic sensor body 1 1 1 is attached to an attachment hole 1 1 20 a formed in a part of a motor case 1 1 2 0 having a motor stay 1 1 2 through an O-ring 1 18. One is tightly fixed. The outer periphery of the end portion 111a of the mouth 111, which is the movable portion of the motor, is provided with a magnetic gear 111 serving as a detector made of a magnetic material. The magnetic sensor body 111 is located to face the toothed wheel 111a of the magnetic gear 111.

The magnetic sensor body is configured as shown in FIG. 12, and has a cup shape of the magnetic sensor body 11 1 11 and an inner end of a cover 1 1 1 1 B having a flange 1 1 1 1 A. 1 1 1 1 lb Step 1 1 1 1 B b is provided with a printed circuit board 1 11 lb having a well-known magnetic sensor 1 1 1 1 a on the front side. On the back side, a bias magnet 1 1 1 1 c is provided. The inside of the cover 1 1 1 1 B is filled with a resin filler material 1 1 1 1 e, and the printed circuit board 1 1 1 1 b is stepped by the resin filler material 1 1 1 1 e. Is held in. Therefore, the inner end 1 1 1 lB b of the magnetic sensor 1 1 1 1 is located inside the motor case 1 1 2 0, and the magnetic sensor 1 1 1 2 End 1 1 1 1 B b is located on the atmosphere side.

However, in this conventional example,

(1) Since the outer end of the magnetic sensor must be located on the atmosphere side, there is a problem that the degree of freedom in designing the motor structure is reduced.

(2) Since magnetic gears are provided on the outer periphery of the end of the rotor, multiple slits such as a binary code method and a vernier method are used to detect the absolute angle within one rotation of the rotor. When the track row is formed, there is a problem that the outer shape becomes large and the inertia of the row becomes large.

[Disclosure of the Invention]

Accordingly, an object of the present invention is to solve the above-mentioned problems by disposing a magnetic sensor and a slit disk in a vacuum, thereby increasing the degree of freedom in motor design without reducing reliability. By using a position detection method and easily forming a plurality of slit tracks on a flat surface using a flat slit disk, and using these to detect the absolute angle within one rotation of the mouth, it is lightweight and thin. It is an object of the present invention to provide a vacuum position detecting device in a vacuum mode that can detect an absolute angle of a vacuum.

A vacuum position detecting method in a vacuum motor according to the present invention comprises a motor case having a stay rotatably rotatable via a bearing in a motor case, a detector rotor provided in the mouth, and the detector described above. In the method for detecting a position by arranging a rotatable device on a vacuum side, the detector port may include a flat slit disk in which a plurality of slits are formed on a plane in a magnetic steel plate, and a slit disk for fixing the slit disk. A magnetic sensor head in which a MR element and a permanent magnet are sealed in resin in a sensor case is provided on the stay side so as to face the slit disk, and the magnetic sensor head is The presence or absence of the slit formed on the slit disk surface is detected in a vacuum.

Further, the method of detecting a vacuum position in a vacuum motor according to the present invention comprises: a motor case having a stay; a rotatable rotatable via a bearing; a detector rotor provided in the rotatable; In the method of detecting the position by disposing the detector rotor on the vacuum side, the detector rotor has a slit whose number of slits per rotation is 2 ^N , 2 ^N ± 1 (where N is a natural number) in the magnetic steel plate. It consists of a flat slit disk in which a plurality of slit tracks including a track are formed on a plane and a slit disk base for fixing the slit disk.On the side of the stay, an MR element and a permanent magnet are placed in the sensor case. A magnetic sensor head encapsulated in resin is arranged opposite the slit disk, and the absolute position per rotation of the motor rotor is detected from the slit track in a vacuum. To.

Further, the vacuum position detecting device in the vacuum motor according to the present invention has a motor case having a stay and a rotatable rotatable via a bearing in a mooring case, and a detector rotatable on the rotor. In a vacuum position detector provided so that the detector port is located on the vacuum side, the detector rotor is a flat slit disk in which a plurality of slits are formed in a plane on a magnetic steel plate and fixed thereto. A magnetic sensor head in which an MR element and a permanent magnet are sealed in resin in a sensor case is provided corresponding to the slit disk. The disk is configured to be located in a vacuum so as to face the slit disk.

Further, the vacuum position detecting device in the vacuum motor according to the present invention comprises: a motor case having a stay and a rotatable rotatable via a bearing; a detector rotor provided on the rotatable; In a vacuum position detecting device for detecting a position by locating a rotatable plate on a vacuum side, the detector port is provided on a magnetic steel plate at a number of slits per rotation of ^2N , ^2N ± 1 (N, Is a natural number) consisting of a flat slit disk in which a plurality of slit tracks including a slit track are formed on a plane, and a slit disk base for fixing the slit track. An MR element and a permanent magnet are provided on the stay side. A magnetic sensor head sealed with resin is placed in the sensor case so as to face the slit disk, and the absolute position per rotation of the motor rotor can be detected in vacuum from this slit track. It is characterized by having been configured to be able to.

The present invention uses an austenitic stainless steel as a sensor case material of the magnetic sensor head, uses a fluororesin as a coating material of the sensor cable protruding from the magnetic sensor head, A permanent magnet is encapsulated in the sensor case with epoxy resin, the MR element and the permanent magnet are encapsulated in the sensor case with alumina-filled epoxy resin, and are fixed around the magnetic sensor head. Providing a fixed collar, making a round hole or a long hole for screwing in the fixing collar, using a silicon steel plate as a magnetic material of the slit disk, or a non-magnetic metal as a material of the slit disk base Can be used.

According to the present invention as described above,

(1) Since the gas emitted from the magnetic sensor and the slit disk can be suppressed and can be placed in a vacuum with corrosion resistance, the degree of freedom in motor design can be increased without reducing reliability. (2) When applied to a vacuum robot, etc., since the absolute angle within one rotation of the rotor can be detected, it is not necessary to return to the home position, etc., even when the power is turned on or when the rotor is stopped for any reason, thus improving productivity. .

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment 1 of the present invention. FIG. 2 is a sectional side view of the magnetic sensor head according to the first embodiment of the present invention. FIG. 3 is a side sectional view of a magnetic sensor head according to a fourth embodiment of the present invention. FIG. 4 is a diagram showing a head output signal waveform of the magnetic sensor according to the embodiment of the present invention. FIG. 5 is a connection diagram of an MR element which is a component of the magnetic sensor head according to the embodiment of the present invention. FIG. 6 is a diagram showing the types of austenitic stainless steel used in the present invention. FIG. 7 is a magnetic sensor head diagram showing an embodiment 5 of the present invention. FIG. 8 is a perspective view showing a configuration for detecting an absolute angle according to the eighth embodiment of the present invention. FIG. 9 is a block diagram of the signal processing circuit 9. FIG. 10 is a diagram for explaining an output form in the signal processing circuit 9. FIG. 11 is a side sectional view of a conventional example. FIG. 12 is a sectional view of a conventional magnetic sensor side.

[Best Mode for Carrying Out the Invention]

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

Example 1

FIG. 1 is a side sectional view showing a first embodiment of the present invention. In FIG. 1, the vacuum position detecting device includes a magnetic sensor head 2 fixed to a stay 1 having a motor coil 11 and a slit sensor fixed to a rotor 3 having a rotatable magnet 10 with screws 9 or the like. A flat slit disk 5 adhered to the disk base 4 with an adhesive or the like is arranged so as to face each other in a vacuum. Since the mouth 3 is attached to the stay 1 via a bearing 6, the slit disk 5 has a mechanism capable of rotating together with the rotor 3 with respect to the magnetic sensor head 2. . Since the slit disk 5 can form a plurality of slit holes on a plane by etching a magnetic steel plate or the like, the slit disk 5 can be made extremely thin, and the external dimensions of the slit can be freely designed.

FIG. 2 is a sectional view showing the configuration of the magnetic sensor head 2. As shown in FIG. The MR element 2b and the permanent magnet 2c are arranged in the non-magnetic sensor case 2a as shown in Fig. 2, and the MR element output line 2 e and the MR element power supply line 2 f are connected to the sensor cable 7 with solder or the like while avoiding the permanent magnet 2 c.

By enclosing the MR element 2b, the permanent magnet 2c, the MR element output line, 2e, the MR element power supply line 2f, and the sensor cable 7 end with the resin 2d in the sensor case 2a, Can be placed in a vacuum. The connector 8 is a connector for outputting an output signal of the magnetic sensor head 2 arranged in a vacuum to the atmosphere side, and is connected to the sensor cable 7 on the vacuum side.

The output signal of the magnetic sensor head 2 is shown in FIG. Due to the reluctance change depending on the presence or absence of the slit hole, a pseudo sine wave with a period corresponding to the slit pitch A-phase and a B-phase signal different in 90 ° phase are output. The sensor cable 7, the MR element output line 2e, and the MR element power supply line 2f are connected as shown in FIG. 5, and the A-phase and B-phase pseudo sine wave signals are converted into AZD signals by a signal processing circuit. Performs conversion and multiplication processing, and outputs the a-phase and b-phase pulse signals shown in Fig. 4 (b).

With the above-described means and configuration, the magnetic sensor head, the slit disk, and the slit disk base can be arranged in a vacuum, so that the degree of freedom in motor design can be increased.

Example 2

In the present embodiment, an austenitic stainless steel that emits little gas and has no magnetism is used as a material of the sensor case 2a of the magnetic sensor head 2. Austenitic stainless steel has a steel type name as shown in Fig. 6. Austenitic stainless steel has no magnetism and has higher strength than aluminum materials, so it is the best magnetic sensor case. In particular, by using SUS303, the shape of the sensor case 2a can be formed relatively freely. In addition, since SUS304 or SUS316 has a small amount of gas generation, gas generation is suppressed by using these materials, and gas generation characteristics are improved.

Example 3

In this embodiment, as shown in FIG. 3, a sensor cable 7a in which the sensor cable 7 is coated with a fluorine resin is connected to the MR element output line 2e and the MR element power supply line 2f. By connecting and enclosing with 2 d of resin, gas generation is kept low and gas generation characteristics are improved.

Example 4

In this embodiment, the use of an epoxy resin as the material of the resin 2d suppresses outgassing and achieves an improvement in outgassing characteristics. Further, if the epoxy resin is an alumina-filled epoxy resin, since the resin contains alumina, when the resin is hardened, its deformation is smaller than that of a normal resin, so that the MR element, the permanent magnet, and the MR element The stress applied to the output line and the MR element power supply line is relaxed, and the MR element and the permanent magnet are not displaced, and the MR element output line and the MR element power supply line are not broken, so that the reliability can be improved.

Example 5

In this embodiment, as shown in FIG. 7A, a fixing collar 2 g is provided on the outer periphery of the sensor case 2 a of the magnetic sensor head 2. By providing the fixing collar 2 g, the distance between the magnetic sensor head 2 and the slit disk 5 can be kept constant, and the positioning of the magnetic sensor head 2 can be facilitated. it can. As an example of a method for fixing the sensor head in this case, there is a method in which a fixing snap is provided in the sensor case and the sensor head is fixed overnight.

Further, by providing a fixing collar 2 h having a round hole for screwing as shown in FIG. 7 (b), a screw can be passed through the round hole in the fixing collar 2 h of the magnetic sensor head 2. It can be easily and firmly fixed to the stay, and it is strong against vibration and the like, and the reliability can be improved.

Further, by providing a fixing collar 2j having a long hole as shown in FIG. 7 (c), the mounting angle of the magnetic sensor head 2 in the rotation direction can be adjusted, and the magnetic sensor head can be adjusted. Since the amplitude and phase of the output signal can be adjusted, the detection accuracy of the magnetic sensor head 2 can be improved.

Note that the shape of the fixing collar 2 g, the fixing collar 2 h having a round hole, and the fixing collar 2 j having a long hole may not be a disk shape, and may be a shape as shown in FIG. 7 (d). It is clear that this is fine.

Example 6 In this embodiment, a silicon steel plate is used as the material of the slit disk 5. If a magnetic steel plate is used as the material of the slit disk 5, a signal can be obtained, but depending on the material, problems such as a decrease in detection accuracy due to unstable magnetic characteristics and a decrease in noise resistance due to a decrease in output signal amplitude occur. . By using a silicon steel sheet as the material of the slit disk 5, it is possible to avoid problems such as a decrease in accuracy due to unstable magnetic characteristics and a decrease in noise resistance due to a decrease in output signal amplitude, and the detection accuracy and reliability are improved. Performance can be improved.

Example 7

In this embodiment, a non-magnetic metal is used as the material of the slit disk base 5. By using a non-magnetic metal, there is no effect on the reluctance change due to the presence or absence of the slit disk 5 slit, so that a stable output signal can be obtained and the reliability can be improved.

Example 8

In the present embodiment, a plurality of slit tracks including a slit track having the number of slits per rotation of 2N and 2N soil 1 are formed on a plane on the slit disk 5, and the motor of the slit is used by the slit tracks. The absolute angle per rotation of the rotor 3 is detected in a vacuum.

Fig. 8 shows a specific configuration example. In FIG. 8, two slit tracks of an A slit track 51 and a B slit track 52 having different numbers of pulses during one rotation are formed on the slit disk 5 by a method such as etching. The head 2 has an MR element 2 b-1 for the A slit track and an MR element 2 b-2 for the B slit track. The slit disk 5 and the magnetic sensor head 2 face each other. It is arranged. Reference numeral 9 denotes a signal processing circuit which takes in the pseudo sine wave signal of the magnetic sensor head 2 and outputs an absolute angle signal. When the slit disk 5 is rotated, a pseudo sine wave A phase with a period corresponding to the slit pitch and a B phase signal having a 90 ° phase difference are output as shown in Fig. 4 (a) due to the reluctance change due to the presence or absence of the slit hole. Further, the A-phase and B-phase signals are converted by the signal processing circuit 9 into absolute angle signals during one rotation. Suritsu DOO 2 ^N = 2 ⁷ = 1 28 of N = 7 per revolution to the A scan Ritsuto track is formed as an example, 2 per revolution 1 slit smaller than A slit track the B slit tracks ^N - 1 = 2 ⁷ - describing 1 = 1 27 If Suritsu Bok is formed a method for detecting the absolute angle signal for the at proc diagram of the signal processing circuit 9 in FIG. In FIG. 9, the MR element 2b-1 for the A-slit track receives a change in magnetic flux of 128 cycles in one rotation of the slit disk 5, and has a 90 ° rotation as shown in FIG. Outputs A-phase and B-phase signals with different phases. Similarly, the B slit track detecting MR element 2b_2 receives a change of magnetic flux of 127 cycles in one rotation of the slit disk 5, and has 127 cycles of A phase and B phase having different 90 ° phases. Output a signal. These output signals are amplified by an amplifier 91 and input to a phase modulation circuit A 92a and a phase modulation circuit B 92b, respectively. In the phase modulation circuits 92a and 92b, the clock signal CK output from the oscillator 97 is input, and the carrier signal 96 having a constant period generated by the carrier signal generation circuit 95 is phase-modulated by the A-phase and B-phase signals. Then, the phase change from 0 ° to 360 ° is repeated 128 times in one revolution of the slit disk, and it is converted into 01 ′ signal which is repeated 127 times and 02 ′ which is repeated 127 times. The 01 ′ and Θ2 ′ signals are binarized signals and have rising edge times with phase information. In the phase difference detection circuit 94, as shown in FIG. 10, a phase change of 0 ° to 360 ° is provided once for one rotation of the slit disk, which is a phase difference between the 0 1 ′ signal and the 02 ′ signal. A signal is output. The 01-02 signal is a phase difference signal obtained by counting the rising edge of the 01 ′ and 02 ′ signals with the clock signal CK and digitizing the counted signal. In the multiplier circuit 93, the interval between the rising edge of the carrier signal 96 and the rising edge of the 01 ′ signal is counted by the clock signal CK. Accordingly, if the period of the carrier signal 96 is I times the period of the clock signal CK (I is a natural number), a digitized phase signal 1 with a division number I can be obtained. By specifying the number of repetitions of the 01 signal by the θ θ−θ2 signal by the absolute value signal generation circuit 98, it is possible to obtain the absolute angle signal 99 of 128 X division number I pulses per rotation.

With this configuration, a high-resolution absolute position signal can be obtained in a vacuum. In addition, not only two slit tracks but also a plurality of slit tracks as in this embodiment. By complementing with a rack, the number of repetitions can be easily specified and reliability can be improved.

It is clear that the above embodiment can be applied to both a single encoder and a linear encoder.

[Industrial applicability]

INDUSTRIAL APPLICABILITY The present invention can be used in the field of manufacturing and providing a vacuum position detecting method and a vacuum position detecting device in a vacuum motor used in a vacuum such as a semiconductor manufacturing apparatus.

Claims

The scope of the claims

1. A motor case having a stay is rotatably provided with a rotor via a bearing, a detector rotor is provided on the rotor, and the detector port is located on the vacuum side to detect a position. In the method,

The detector rotor is composed of a flat slit disk in which a plurality of slits are formed on a magnetic steel plate on a plane, and a slit disk base for fixing the slit disk. A magnetic sensor head enclosing resin in a sensor case is provided so as to face the slit disk, and the presence or absence of the slit formed on the slit disk surface is determined in a vacuum by the magnetic sensor head. A method for detecting a vacuum position in a vacuum mode, characterized in that the position is detected by a vacuum.

2. A rotatable case is rotatably provided via a bearing in a motor case having a stay, a detector rotor is provided on the rotor, and the detector rotor is arranged on the vacuum side to detect a position. In the method,

The detector is a flat plate formed by forming a plurality of slit tracks on a magnetic steel sheet, including a plurality of slit tracks having a number of slits per rotation of 2 ^N and 2 ^N ± 1 (where N is a natural number). A magnetic sensor head in which a MR element and a permanent magnet are sealed in resin in a sensor case faces the slit disk. And detecting the absolute position per rotation of the motor rotor from the slit track in a vacuum in a vacuum motor.

3. A motor case having a stay is rotatably provided with a port through a bearing through a bearing, and a detector port is provided at the port described above, and the detector rotor is arranged on the vacuum side. In the vacuum position detection device

The detector is composed of a flat slit disk in which a plurality of slits are formed on a magnetic steel plate on a plane, and a slit disk base for fixing the slit disk. A magnetic sensor head in which a magnet and a sensor cable end connected to a signal output and a power supply terminal of the MR element are sealed in a sensor case with resin is provided corresponding to the slit disk, and the magnetic sensor head is provided. Slip in vacuum A vacuum position detecting device in a vacuum motor, characterized in that it is configured to be located opposite to a disk.

4. The vacuum position detection in vacuum mode according to claim 3, wherein austenitic stainless steel is used as a sensor case material of the magnetic sensor head.

5. The vacuum position detecting device according to claim 3, wherein a fluorine resin is used as a coating material of the sensor cable protruding from the magnetic sensor head.

6. The vacuum position detecting device in a vacuum motor according to claim 3, wherein the MR element and the permanent magnet are sealed in the sensor case with epoxy resin.

7. The vacuum position detection in a vacuum motor according to claim 3, wherein the MR element and the permanent magnet are sealed in the sensor case with epoxy resin filled with alumina.

8. The vacuum position detecting device in a vacuum motor according to claim 3, wherein a fixing collar is provided on an outer periphery of the magnetic sensor head.

9. The vacuum position detecting device in a vacuum motor according to claim 3, wherein a round hole or a long hole for screwing is formed in the fixing collar.

10. The vacuum position detecting device in a vacuum motor according to claim 3, wherein a gay element steel plate is used as a magnetic steel plate material of the slit disk.

11. The vacuum position detecting apparatus according to claim 3, wherein a non-magnetic metal is used as a material of the slit disk base.

1 2. A rotor case is rotatable via a bearing in a motor case having a stay and a detector, a detector rotor is provided in the rotor, and the detector rotor is arranged on the vacuum side to detect a position. In the vacuum position detector,

The detector is a flat plate formed by forming a plurality of slit tracks on a magnetic steel sheet, including a plurality of slit tracks having a number of slits per rotation of 2 ^N and 2 ^N ± 1 (where N is a natural number). A magnetic sensor head in which a MR element and a permanent magnet are sealed in resin in a sensor case is opposed to the slit disk. Placed in this A vacuum position detecting device in a vacuum motor, wherein an absolute position per one rotation of a motor rotor is detected in a vacuum from a slit track.