JP2913520B2 - Centrifugal acceleration measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal acceleration measuring device, and more particularly to a centrifugal acceleration measuring device in which a turntable is directly driven by a brushless motor, and the turntable is rotatably supported by an air bearing to achieve high precision. The present invention relates to a centrifugal acceleration measurement device capable of measuring acceleration at a time.

[0002]

2. Description of the Related Art A centrifugal acceleration measuring device rotates a turntable in a horizontal plane, and a measured acceleration converter (hereinafter referred to as an "acceleration converter") is mounted on a periphery of the turntable via a jig.
The turntable is rotated to apply centrifugal acceleration to the acceleration converter on the turntable, and the output characteristics at this time are verified and measured.

In such a centrifugal acceleration measuring device, an induction motor is used as a motor for rotating the turntable, and its rotational force is transmitted via a belt, a multi-stage gearbox, a clutch, etc., and stopped. Occasionally, the brakes are applied.

[0004] In addition, the control of the number of revolutions of the motor is also performed by an open loop system.

On the other hand, the rotation support of the turntable is mechanically supported by a ball bearing.

[0006] With the rotation of the turntable,
The acceleration converter detects the centrifugal acceleration, and the detected output is transmitted to the measurement system via the signal transmission system. As the signal transmission system, since the turntable is rotating and the measurement system is installed at a stationary position, an analog transmission system using mechanical contact using a slip ring and a brush is employed. .

[0007] The detection output via the transmission system is input to the measurement system as an analog signal, converted into a digital signal, and then sent to a central processing unit (hereinafter "CP") via an input / output circuit.
U ").

After a predetermined analysis process is performed by the CPU, the analysis result is displayed on a display device or printed out on a printer.

Further, power is generally supplied to the acceleration converter provided on the turntable by a slip ring system.

[0010]

In a conventional centrifugal acceleration measuring device, first, in a rotary drive system of a turntable, an induction motor or the like is used, so that brush sliding noise is generated. There is a drawback that it is mixed in the detection output, and since the drive transmission is performed via a belt, a multi-stage gear box, a clutch, etc., the device becomes large, and vibration is added to the turntable, and accurate It was difficult to provide acceleration to the acceleration transducer.

Also, since the transmission system of the detection output is based on a mechanical analog transmission system using a slip ring or a brush, the detection output of abrasion at a sliding portion, poor contact, and noise accompanying the contact is obtained. Is inevitable.

Further, the supply of electric power to the measuring system is of the sliding type using a slip ring or a brush, as described above, so that wear is inevitable.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to prevent unnecessary vibration from being generated or given to a turntable. It is an object of the present invention to provide a centrifugal acceleration measuring device which can apply only the acceleration of the acceleration converter and can detect only the output of the acceleration converter to be measured without generating noise from a driving source or a signal transmission system.

[0014]

According to the present invention, there is provided a stone surface plate supported on a vibration isolator,
And <br/> brushless motor housed fixed to the motor housing portion is bored in the stone surface plate, directly by the brushless motor
Is rotated, a bottom for mounting the measured acceleration transducer
The acceleration transducer mounting part , which forms a short cylindrical space, is formed at an equiangular interval at a part eccentric from the center of rotation , and
A turntable having a cavity formed in the center thereof , an air bearing for rotatably supporting the turntable in a non-contact state, and a turntable accommodated in the cavity of the turntable.
A built-in amplifier for individually amplifying the output of the measured acceleration converter, and an A / D converter output from the built-in amplifier.
Conversion, parallel - serial data conversion and signal modulated signal provided with a rotary transformer for transmitting to the fixed part side, the turntable the <br/> measured acceleration transducer is attached
Is completely independent of the stone surface plate and the stationary side of the motor.
While being supported by the air bearing in the contact state,
Disconnect at least the signal output from the acceleration converter.
It is configured to be led out to the fixed portion side by the rotary transformer in a contact state . Also the above eye
To achieve better targets, brushless motors
Measures the number of revolutions of the brushless motor and encodes it.
The output of the encoder is referenced to the pulse of the pulse generator.
Phase comparison, and set according to the phase difference.
The motor controller adjusts its rotation speed to
Characterized in that the degree is controlled.
is there.

[0015]

According to the present invention, the turntable is directly driven and rotated by the brushless motor according to the present invention, and the rotated turntable is rotatably supported in a non-contact state by an air bearing, so that unnecessary vibration is applied to the turntable. Absent.

A plurality of acceleration converters provided on the turntable respectively detect accelerations associated with the horizontal rotation of the turntable, and output their detection outputs to individually built-in amplifiers. The output is appropriately amplified and, if necessary, converted to a digital signal.

The converted output is transmitted to a measurement system disposed at a fixed part other than the turntable via a rotary transformer provided at a rotating part corresponding to each acceleration converter.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a front view showing an entire configuration of an embodiment of a centrifugal acceleration measuring device according to the present invention.

In FIG. 1, reference numeral 1 denotes a stone surface plate formed in a disk shape. The lower surface of the stone surface plate 1 is fixed to a support 3 via a vibration isolator 2 such as an oil damper or an air damper. A plurality of columns 3 and four (in this case, four) vibration isolation devices 2 are provided. The lower end of the column 3 is fixed to a flat floor surface.

At the center of the stone surface plate 1, a penetrating motor housing is provided, and a brushless motor 4 (hereinafter simply referred to as "motor") is housed therein. Motor 4
Is configured to directly rotate the turntable 5 without passing through a belt or a gearbox for speed change, and a rotating shaft supporting portion 5 a suspended on the lower surface of the center of the turntable 5 and a rotating shaft of the motor 4. Is directly connected.

An air bearing 6 is interposed between the motor 4 and the turntable 5, and a rotary shaft 5a of the turntable 5 is fitted and connected to a rotary cylinder provided at the center of the air bearing 6. The rotating cylinder is rotatably supported on the fixed cylinder by air.

An air pressure supply section 6a is provided on the outer peripheral surface of the air bearing 6. Compressed air is supplied to the air pressure supply unit 6a from the air cleaner 7 shown in FIG. 2, so that the rotary cylinder part in which the rotary shaft support part 5a of the turntable 5 is fitted is rotatably supported in a non-contact state. Has become.

FIG. 2 is a block diagram schematically showing the entire configuration of the present invention.

As is apparent from FIG. 2, an air source 8 is connected to the air cleaner 7. After the air supplied from the air source 8 removes dust and the like by the air cleaner 7, the air is regulated to a predetermined pressure (for example, 3 to 10 kg / cm ² by an air regulator (not shown)). Pressure regulation).

The regulated air is supplied to the air pressure supply section 6a of the air bearing 6, and is also supplied to the vibration isolator 2 through the column 3 as shown in FIG. It is supposed to.

The air bearing 6 and the turntable 5
The detailed configuration of the rotary shaft support 5a is shown in an enlarged sectional view of FIG.

In FIG. 3, the structure of the turntable 5 will be described first. Rotary shaft support 5 of turntable 5
In a, a cavity portion 5a1 is formed, and a multiplexer 31, a controller 32, an A / D converter 33, a PS converter 34, and a modulator 3, which will be described later, are a part of a built-in amplifier therein.
5 etc. are stored. The multiplexer 31, the controller 32, and the like will be described later in detail with reference to FIG.
The cover 10 is fixed and closed at the upper end of the cavity 5a1.

A storage section 5a2 for storing cords and the like is provided above the rotary shaft support section 5a. This storage section 5
On the outer peripheral portion of a2, an acceleration converter mounting portion 5a3 having a diameter larger than that of the storage portion 5a2 is formed.

In this embodiment, the acceleration transducer mounting portion 5a
3 is formed in a short cylindrical space with a bottom, and a turntable 5
Are provided at equal angular intervals with respect to the rotation center. As shown in the block diagram of FIG. 4, the acceleration converters 12a to 12d are stored one by one in the four acceleration converter storage sections 5a3, and a total of four acceleration converters are stored in the turntable 5 as a whole. It has become so.

First, the turntable 5 is fitted with the annular groove of the connection block 5b and the outer peripheral portion of the rotary cylinder 6b of the air bearing 6 so that the turntable 5 can be freely rotated in the horizontal direction. A plurality of bolts 5 from the upper surface of 5b
b2 at a predetermined angular interval, and
Are integrally connected by being screwed into a female screw hole formed in the hole.

Further, in a state where the upper surface of the connecting block 5b is in contact with the lower surface of the rotary shaft support 5a of the turntable 5, a plurality of bolts 5b are formed from the upper surface of the rotary shaft support 5a.
1, the connecting block 5b is connected to the rotating shaft support 5a.

As a result, the fixed shaft support 5a is connected to the rotary cylinder 6b of the air bearing 6 via the connection block 5b. The rotary cylinder 6b is rotatably supported by the press-fitted air with a small gap with respect to the fixed cylinder of the air bearing 6, so that the turntable 5 is rotatably supported on the air bearing 6 in the horizontal direction. become.

Here, the description returns from FIG. 3 to FIG. As shown in FIG. 1, the air bearing 6 and the turntable 5 are included on the above-mentioned stone surface plate 1 so that
A safety cover 11 is fixed on the stone surface plate 1.

The safety cover 11 is provided so that even if the acceleration transducer comes off the turntable 5 during the test, the safety cover 11 prevents the operator from scattering on the turntable 5 during operation. This is to prevent touch.

Next, a transmission system and a processing system of the detection output will be described with reference to FIGS. As shown in FIG.
In this embodiment, the four acceleration converters of the first to fourth acceleration converters 12a to 12d can be measured simultaneously.

These first to fourth acceleration converters 12a to 12d are respectively stored and mounted on the four acceleration converter mounting portions 5a3 of the turntable 5 shown in FIGS. 1 and 3. Have been.

The first to fourth acceleration converters 12a to 12d are strain gauge type acceleration converters in this example, and each of the acceleration converters 12a to 12d has a rotation speed of the turntable 5, that is, The acceleration detection output is obtained by detecting the distortion corresponding to the acceleration. When the rotation speed of the motor 4 is increased or decreased stepwise, the acceleration that changes stepwise can be detected.

The detection outputs of the first to fourth acceleration converters 12a to 12d are input to the multiplexer 31 housed in the housing 5a2.

The multiplexer 31 is provided with a first acceleration converter 12a to a fourth acceleration converter 1 based on an output signal of a controller 32 having a built-in sequence counter (not shown).
The 2d output is input individually, that is, data for 4 channels is input for each channel, and sequentially switched to 1d.
The data is output to a 2-bit analog / digital (hereinafter, referred to as “A / D”) converter 33.

The A / D converter 33 converts each output of the first to fourth acceleration converters 12a to 12d output from the multiplexer 31 into a digital signal based on the controller signal of the controller 32. The signal is output to a parallel-serial (hereinafter, referred to as “PS”) converter 34.

The PS converter 34 includes a controller 3
The 12-bit digital signal output from the A / D converter 33 is serially converted by the control signal of No. 2 and output to the modulator 35.

Although not shown in the modulator 35,
An oscillator is built-in, and modulates each “1” and “0” of serially converted data input from the PS converter 34 based on an output signal of the controller 32.

In the case of this embodiment, the output signal (pulse signal) of the oscillator is modulated so that the serial data "1" is 50 KHz and "0" is 25 KHz, and is output to the primary side of the rotary transformer 36. ing.

This rotary transformer 36 is, as shown in FIG.
The motor 4 is arranged at a position below the rotating main shaft. In FIG. 4, the primary windings 36P and 2
The secondary winding 36S is electromagnetically coupled in synchronization with the rotation of the motor 4.

50 KHz and 25 KHz corresponding to "1" and "0" induced in the secondary winding 36S of the rotary transformer 36.
Are input to the demodulator 37.

A control signal from a controller 38 is input to the demodulator 37.
With this control signal, the demodulator 37 demodulates the induced signal of the secondary winding 36S of the rotary transformer 36 into digital measurement data, and performs serial-parallel (hereinafter, "S-
P ”) to the converter 39.

A control signal from the controller 38 is also input to the SP converter 39. Based on this control signal, digital serial data output from the modulator 37 is converted into 12-bit parallel data.

The parallel data is supplied to four latch circuits 40a to 40d for each channel based on an output signal from the controller 38, that is, the first acceleration converter 12a
The output is latched in accordance with the outputs of .about.12d.

These four latch circuits 40a-40d
Are input to digital / analog (hereinafter, referred to as “D / A”) converters 41 a to 41 d, respectively, and a binary-coded decimal converter (hereinafter, referred to as “D / A”).
(Referred to as “BCD converter”) 42.

The BCD converter 42 includes a latch circuit 4
Outputs for each of 0a to 40d are input, converted into decimal digits by a binary-coded decimal system, and output to the display device 43. The display device 43 corresponds to a CRT display device or the like.

Although not shown in FIG. 4, the output of the SP converter 39 is output from the CP converter 39 as shown in FIG.
U15, a keyboard 16, a printer 18 and the like are connected to the CPU 15, and the CPU 15 analyzes the acceleration detection outputs detected by the first acceleration converter 12a to the fourth acceleration converter 12d. Keyboard 1
By performing the operation 6, various data processing is performed, and the result of the analysis processing can be printed out by the printer 18 as measured value data.

4, the components from the first acceleration converter 12a to the fourth acceleration converter 12d to the rotary transformer 36 are arranged on the rotating part side, and the parts from the demodulator 37 to the display device 43 are fixed. It is arranged on the part side.

FIG. 5 shows an example of the arrangement of the analysis processing system, in which a keyboard 16 and a CPU 15 are arranged on a disk 19 with casters, and the display device 43 shown in FIG. Printer 1 on the shelf
8 are placed.

In FIG. 4, a clock pulse is output from the pulse generator 20 to the motor controller 21.

The output of the encoder 22 is input to the motor controller 21. The encoder 22 measures and encodes the number of rotations (rotational angular velocity) of the motor 4, and the motor controller 21
The phase of the output of the encoder 22 is compared with the pulse of the pulse generator 20 as a reference, and the rotational speed of the motor 4 is controlled to a predetermined set speed according to the phase difference.

The encoder 22 is arranged below the motor 4 as shown in FIG.

Reference numeral 23 denotes an external power supply provided on the fixed side. The output of the external power supply 23
, The power is supplied to the regulator 24. The rotary transformer 13 can supply power from the external power supply 23 to the regulator 24 in a non-contact state without using a slip ring or a brush.

The regulator 24 rectifies an AC voltage supplied from the external power supply 23 into a DC voltage, and then supplies the DC voltage as a predetermined constant voltage to the multiplexer 31, the controller 32, and the like.

As shown in FIG. 2, the pulse generator 20, the motor controller 21, the external power source 23, etc.
The noise filter 26 and the shield transformer 27 are accommodated in the bottom of the rack 25 with a caster.
The setting of the number of rotations can be switched by operating the switch 28.

The set rotation speed for each operation of the switch 28 is displayed on the display device 43.

The operation of this embodiment thus configured will be described.

First, the external power supply 23 supplies the rotary transformer 13
Power is supplied to the regulator 24 via the controller 24, the AC voltage supplied from the external power supply 23 is rectified by the regulator 24 into a DC voltage, and then the voltage is set to a constant voltage and the multiplexer 3
1. Supply operating power to the controller 32 and the like.

By operating the switch 28 shown in FIG.
By setting the rotation speed of the motor 4, that is, the acceleration, the set rotation speed is displayed on the display device 43.

When the motor 4 is rotated at the set rotation speed, the actual rotation speed of the motor is measured by the encoder 22 and the measured value is encoded.
Is sent to the motor controller 21.

The motor controller 21 compares the phase of the pulse input from the pulse generator 20 with the phase of the output of the encoder 22, and determines the rotation speed of the motor 4 according to the phase difference so that the rotation speed of the motor 4 becomes the set rotation speed. Perform control.

Since the motor 4 is a brushless motor and directly drives the turntable 5, the turntable 5 can be rotated with a high centering accuracy and a small jitter (JITTER).

FIG. 6 is a characteristic diagram showing the relationship between the command voltage and the rotation speed of the motor 4. As is apparent from FIG. 6, the rotation speed is almost linear with respect to the command voltage. FIG. 7 is a characteristic diagram showing the relationship between the jitter and the number of rotations, and it can be seen that the jitter is extremely small.

FIG. 8 is a diagram showing the rise of the motor 4 and
It shows the falling characteristic, and it can be seen that the rising and falling are symmetrical and there is no unevenness.

As can be seen from FIGS. 6 to 8, the characteristics of this brushless motor are excellent. Therefore,
The rotation of the turntable 5 directly driven by the motor 4 is extremely stable without any misalignment, and thus very accurate acceleration can be given to the first to fourth acceleration converters 12a to 12d.

The rotating shaft support 5a of the turntable 5 rotated by the motor 4 is integrated with the rotating cylinder 6b of the air bearing 6, and is rotatable in a non-contact state with the fixed cylinder of the air bearing 6. No mechanical vibration is generated because the shaft is supported. In addition, there is no wear or seizure, and from the motor 4 and the rotary transformers 13a to 13d,
Since noise is not generated by the conventional brush, noise is not superimposed on the detection outputs of the first to fourth acceleration converters 12a to 12d, and acceleration detection can be performed with higher accuracy.

As described above, by performing the rotation and the rotation support of the turntable 5, the acceleration corresponding to the rotation speed of the turntable 5 is stored and fixed in each of the acceleration converter mounting portions 5a3 of the turntable 5. The first acceleration converter 12a to the fourth acceleration converter 12d can be provided accurately.

The detection outputs of the first to fourth acceleration converters 12a to 12d are individually input to the multiplexer 31. Based on the control signal of the controller 32, the multiplexer 31 outputs each of the outputs of the first to fourth acceleration converters 12a to 12d, in other words, the first to fourth acceleration converters 12a to 12d. The detection outputs of the first acceleration converter 12a to the fourth acceleration converter 12d are selected for each of the first to fourth channels corresponding to the above, and are output to the A / D converter 33.

The A / D converter 33 converts the analog detection output of each of the first to fourth acceleration converters 12a to 12d output from the multiplexer 31 into a 12-bit digital signal based on the output signal from the controller 32. The data is converted and output to the PS converter 34.

In the PS converter 34, the 12-bit first acceleration converter 12 output from the A / D converter 33
The parallel data of the detection output for each of the a to fourth acceleration converters 12 d is converted into serial data based on the output signal from the controller 32 and output to the modulator 35.

In the modulator 35, based on the output signal of the controller 32, the output signal of the oscillator incorporated in the modulator 35 is converted into “1”, “0” of the serial data sent from the PS converter 34. 50KHz, 2
The primary winding 36 of the rotary transformer 36 is modulated to 5 KHz.
Apply to P.

The serial data modulation signal induced in the secondary winding 36S of the rotary transformer 36 is input to the demodulator 37. The demodulator 37 modulates the modulated signal based on the output signal of the controller 38, outputs serial data “1” and “0”, and sends the serial data to the SP converter 39.

The SP converter 39 converts the demodulated signal of serial data sent from the demodulator 37 into parallel data based on the output signal from the controller 38, and converts the demodulated signal into parallel data. For each detection output of the acceleration converter 12d, it is latched by the latch circuits 40a to 40d based on the control signal of the controller 38.

The parallel data latched by each of the latch circuits 40a to 40d is sent to D / A converters 41a to 41d, and the D / A converters 41a to 41d use the first acceleration converter 12a to the fourth acceleration converter. The detection output is converted into an analog signal and output for each device 12d.

The outputs of the latch circuits 40a to 40d are converted into decimal digits by a binary-coded decimal system by a BCD converter 42, and output to a display device 43 for display.

On the other hand, the parallel data output from the SP converter 39 is sent to the CPU 15 shown in FIG. 5 so that the first acceleration converter 12a to the fourth acceleration converter 12d
The result of the analysis can be displayed on the display device 43 or printed out by the printer 18 by operating the keyboard 16 by the operator.

It is also possible to use a general-purpose personal computer for such an analysis processing system to manage product history and to provide a statistical processing function.

Of course, a dedicated microcomputer can be used instead of a personal computer.

Next, if the setting of the rotational speed of the motor 4 is switched in a stepwise manner by operating the switch 28, the first acceleration converters 12a to 12a to 12b are switched in accordance with the stepwise rotation switching.
The step-like acceleration is applied to the fourth acceleration converter 12d, and the respective outputs of the acceleration converter at that time can be derived, and therefore, the multi-stage acceleration setting can be programmed. .

As described above, according to this embodiment, the turntable 5 is directly driven to rotate by the brushless motor 4, and the rotary shaft supporting portion 5 a of the turntable 5 is rotatably driven in a non-contact state by the air bearing 6. The acceleration detection outputs of the plurality of acceleration converters mounted and fixed on the turntable 5 are supported by the first acceleration converters 12 a to 12 a.
The signals are input to the multiplexer 31 for each channel of the fourth acceleration converter 12d, selected for each detection output of each acceleration converter, converted into digital signals by the A / D converter 33, and then converted to PS. The serial data is converted into serial data by a modulator 34, and the serial data "1" and "0" are modulated by a modulator 35 to 50 KHz and 25 KHz, respectively. Since transmission to the disposed demodulator 37 is performed, generation and wear of noise in the motor 4 are eliminated, power consumption is reduced, and noise is not superimposed on the detection output.
In addition, there is an advantage that the whole can be configured to be small.

Further, since the air bearing 6 is used to support the rotation, the rotational accuracy in either the thrust or radial direction can be increased to about 0.05 μm, and an accurate acceleration can be generated accordingly.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention, such as using a magnetic bearing instead of an air bearing.

[0088]

As described above in detail, according to the present invention, first, the brushless motor is supported on the vibration isolator.
It is stored and fixed in the motor storage part drilled on the
Vibrating impact from the floor
Is absorbed (blocked), and mixed as measurement noise.
Not only the vibration of the brushless motor of
It has the advantage of blocking the transmission of motion. Especially the brush
Heavy stones without mounting the motor directly on the vibration isolator
Mounted via a surface plate, the natural frequency of the vibration isolator
Can be reduced, measurement of the measured
Perform calibration in a wide range from low acceleration to large acceleration
I can do it for sure. Note that the stone surface plate
Is less stable and has a lower linear expansion coefficient than metals.
Small, no corrosion, long-term stability of acceleration measurement
It will greatly contribute to realization. Second, according to the present invention,
The turntable is directly connected by a brushless motor
Since it is configured to be driven, a clutch and a speed change mechanism are not required, the whole device can be downsized, noise generation is suppressed, and acceleration can be easily set in multiple stages, and automatic Program acceleration measurement can be realized. Third, the accelerometer to be measured is installed on the turntable.
Acceleration transformation in short cylindrical space with bottom for mounting
The container mounting part is equidistantly spaced from the center of rotation
And a cavity for accommodating the built-in amplifier.
Because it is formed in the center, the measured acceleration transducer and built-in
The position of the center of gravity of the part where the amplifier is
Air gap between rotating element of bearing and housing
Is very small (for example, about 5 microns).
Need to take the dynamic balance of
The above configuration is indispensable from the viewpoint of taste.

Fourth, according to the present invention, air
Therefore, this turntable is rotatably supported in a non-contact state.
Since configured to approval, the thrust from Rukoto also be realized highly accurate rotational support is for any radial,
In particular, a large acceleration can be generated, and in addition, noise is not generated. Therefore, a highly accurate acceleration measurement can be performed.

[0090] Fifth, according to the present invention, the acceleration detection output of the acceleration transducer, parallel after amplifying with built-in amplifier - straight
Since column data conversion and signal modulation are performed and transmitted via a rotary transformer, even in this case,
Non-contact state is maintained, the same, and with the generation of noise can be suppressed, and none of mechanical wear parts maintenance
A centrifugal acceleration measurement device that can eliminate the need for acceleration , and can be applied to a calibration device serving as a reference for acceleration generation. In short, conventionally, complex unknown
Schools that can accurately calibrate the accelerometer due to factors
In the absence of the correct device, the present invention
Of the turntable rotation speed, which has the greatest effect on the
Stabilization is performed, and during detection output of the measured acceleration transducer,
Sliding brush with looseness of sliding part of motor drive system that is easy to enter
Vibration caused by sliding contact, transmitted from floor to turntable
In addition to shutting off all vibrations, etc.
As a non-contact state, the cause of sliding noise is eliminated and S
/ N ratio and non-linearity are greatly improved, and therefore high accuracy
Measurement and calibration of various acceleration transducers and maintainers
To provide a centrifugal acceleration measurement device that can eliminate
Can be. In addition, the brushless motor
An encoder that measures and encodes the rotation speed of the motor
Output is phased with respect to the pulse of the pulse generator.
Performs comparison and reaches a predetermined set speed according to the phase difference
The rotation speed is controlled by the motor controller
So that one cycle of the turntable (1
Rotation), the stability of the time required is high,
Extremely low turntable rotation can be achieved
it can.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an entire configuration of an embodiment of a centrifugal acceleration measuring device according to the present invention.

FIG. 2 is a block diagram showing an overall schematic configuration of the embodiment of FIG. 1;

FIG. 3 is an enlarged sectional view of a portion related to the turntable and the air bearing of the embodiment of FIG. 1;

FIG. 4 is a block diagram of a signal transmission system and a rotation drive system of the embodiment of FIG. 1;

FIG. 5 is an explanatory diagram showing an arrangement relationship of an analysis processing system in the embodiment of FIG. 1;

FIG. 6 is a characteristic diagram showing a relationship between a command voltage and a rotation speed of the motor of the embodiment of FIG. 1;

FIG. 7 is a characteristic diagram showing a relationship between a rotational speed and a jitter of the motor of the embodiment of FIG. 1;

FIG. 8 is a characteristic diagram showing a relationship between a command voltage and a rotation speed of the motor of the embodiment of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stone surface plate 2 Anti-vibration device 3 Prop 4 Motor 5 Turntable 5a Rotation shaft support 5a3 Acceleration converter mounting part 5b Connecting block 6 Air bearing 6a Air pressure supply part 6b Rotating part 7 Air cleaner 8 Air source 10 Cover 11 Safety cover 12a first acceleration converter 12b second acceleration converter 12c third acceleration converter 12d fourth acceleration converter 13,36 rotary transformer 15 CPU 16 keyboard 18 printer 20 pulse generator 21 motor controller 22 encoder 23 external power supply 24 regulator 31 multiplexer 32, 38 Controller 33 A / D converter 34 PS converter 35 Modulator 36P Primary winding 36S Secondary winding 37 Demodulator 39 SP converter 40a-40d Latch circuit 41a-41d D / A conversion Container 42 BCD converter 43 Display device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-6668 (JP, A) JP-A 2-97670 (JP, U) JP-A 63-36167 (JP, U) JP-A 61-66 79207 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01P 21/00

Claims (2)

(57) [Claims] And 1. A stone surface plate supported on vibration damping device, a brushless motor that is housed fixed to the motor housing portion is bored in the stone surface plate, this brushless motor is driven directly rotated, the measured at a site <br/> acceleration transducer mounting portion forming a short cylindrical space having a bottom for mounting the acceleration transducer is eccentrically from the rotational center like
It is formed at angular intervals and a cavity is formed in the center.
The turn table, yield in the cavity portion of the air bearing and the turntable rotatably supporting the turntable in a non-contact state
Are paid fixed, the built-in amplifier for amplifying individually the output of the measuring acceleration transducers, output from the built-in amplifier and A / D converter, a parallel - serial
Comprising a rotary transformer for transmitting the column data conversion and signal modulated signal to the fixed portion side, and the measuring the acceleration transducer is attached above
Turn the turntable with the stone platen and the motor stationary.
Side is completely out of contact with the air bearing.
And at least output from the acceleration transducer.
A centrifugal acceleration converter, wherein a signal to be transmitted is guided to the fixed portion side by the rotary transformer in a non-contact state . 2. The brushless motor according to claim 1, wherein the output of the encoder which measures the rotation speed of the brushless motor and encodes the phase is compared with a pulse of a pulse generator as a reference and a predetermined speed is set in accordance with the phase difference. 2. The centrifugal acceleration measuring device according to claim 1, wherein the rotation speed is controlled by a motor controller .