Laser type rotating speed measuring instrument calibration device

Abstract

The invention relates to a laser type rotating speed measuring instrument calibration device, which comprises a rotating speed generating device, and the rotating speed generating device comprises a base at the bottom, a rotor which is arranged above the base and is connected with a built-in engine of the rotating speed generating device, and a cutting slide block which is arranged beside the rotor. Laser signals are processed through rotation of the rotor and mutual cooperation of the rotor and the cutting slide block, the rotor is fixedly installed on a rotating shaft of a built-in engine of the rotating speed generating device, the rotating shaft drives the rotor to rotate at a set rotating speed through work of the built-in engine, and one face, used for reflecting laser, of the cutting slide block is a smooth tangent plane. A clamping groove is formed in the back face and matched with a sliding groove formed in the rotating speed generating device, and sliding movement in the direction close to or away from the rotor is achieved.

Description

Technical Field

[0001] The present invention relates to a device for calibrating measuring instruments, and in particular, discloses a calibration device for a laser rotational speed measuring instrument, which improves the standard rotational speed generating device and is applicable to the rotational speed calibration of a laser Doppler rotational speed measuring instrument. Background Art

[0002] A rotational speed measuring instrument generally consists of two parts: a rotational speed sensor and a data acquisition and analyzer. Common non-contact rotational speed sensors can be divided into magnetoelectric, magnetosensitive, capacitive, laser, etc.

[0003] The calibration principle of magnetoelectric and magnetosensitive rotational speed measuring instruments can be generally summarized as calibrating by using the electromagnetic induction between the sensitive element and the magnetically conductive material on the edge protrusion of the speed measuring gear on the rotational speed generating device.

[0004] The laser rotational speed measuring instrument obtains the rotational signal through the laser reflection principle for rotational speed measurement. In the past, when calibrating it, a slender reflective paper could be pasted along the radius of the speed measuring gear, and when the laser passed through the reflective paper, specular reflection occurred and was then received by the laser rotational speed measuring instrument. However, it was found during the calibration process that due to the relatively smooth surface of the speed measuring gear, in addition to diffuse reflection, partial specular reflection also occurred when the laser entered the area of the speed measuring gear where no reflective paper was pasted. This interference signal may cause instability or inaccuracy of the indication of the laser rotational speed measuring instrument. Therefore, it is necessary to improve the existing standard rotational speed device so that it can accurately complete the calibration of the laser rotational speed measuring instrument. Summary of the Invention

[0005] The purpose of the present invention is to solve the defects of the existing technology, design a calibration device for a laser rotational speed measuring instrument, make a general improvement to the same type of standard rotational speed generating device, make up for the defect of unstable indication of the speed measuring instrument when calibrating the laser rotational speed measuring instrument with the standard rotational speed generating device, and achieve the verification and calibration of the laser rotational speed measuring instrument that meet the requirements of the verification regulation JJG 1134 - 2017 "Rotational Speed Measuring Instrument".

[0006] The present invention is implemented as follows: A calibration device for a laser rotational speed measuring instrument, characterized in that: it includes a rotational speed generating device, and the rotational speed generating device includes a base at the bottom, a rotor connected to the built-in engine of the rotational speed generating device above the base, and a smooth cutting block arranged beside the rotor. The laser signal is processed through the cooperation of the rotation of the rotor and the smooth cutting block. The rotor is fixedly installed on the rotating shaft of the built-in engine of the rotational speed generating device, and the rotating shaft drives the rotor to rotate at a set rotational speed through the operation of the built-in engine. The surface of the smooth cutting block for reflecting the laser is a smooth cutting surface, and a card slot is arranged on the back, which is matched and installed with the sliding groove arranged on the rotational speed generating device and is slidably connected in the direction approaching or departing from the rotor.

[0007] The position of the cutting smooth block is horizontally slid and positioned along the sliding groove according to the laser incident point, and the horizontal center line of the sliding groove is at the same height as the axis of the rotating shaft.

[0008] The rotor is designed with a detachable structure and is fixedly installed on the rotating shaft through a bayonet or screws, and the two rotate coaxially. According to the installation method with the rotating shaft, the rotors are divided into an elliptical top surface rotor with eccentric installation, a circular top surface rotor with centered installation, and a multi-tooth rotor. The circular top surface rotor is divided into a single-hole circular surface rotor and a multi-hole circular surface rotor. The rotor can correspondingly modulate the laser signal into a positive-polarity pulse signal and a negative-polarity pulse signal, so that the signal presents different duty cycles. The inspector can select an elliptical top surface rotor, a multi-tooth rotor, a single-hole circular surface rotor, or a multi-hole circular surface rotor according to the type of the internal signal processor of the laser-type tachometer under test.

[0009] The maximum value of the vertical distance from each point on the top surface edge of the elliptical top surface rotor to the rotating shaft d 1,max and the minimum value d 1,min are not equal, where: the maximum value d 1,max must be less than the vertical distance from the rotating shaft to the base, and it is recommended d 1,min ≤2 / 3 d 1,max The thickness of the top surface of the elliptical top surface rotor t The value of 1 satisfies being greater than or equal to 1 / 10 of the maximum value d 1,max and less than or equal to 1 / 5 of the maximum value d 1,max to avoid deformation of the top surface of the elliptical top surface rotor due to too small thickness, or damage to the rotating shaft caused by too large dynamic eccentricity moment due to too large thickness.

[0010] The radii of the multi-tooth rotor, the single-hole circular surface rotor, and the multi-hole circular surface rotor R must all be less than the vertical distance from the rotating shaft to the base, and the thickness t The value of 2 satisfies being greater than or equal to 1 / 10 of the radius R and less than or equal to 1 / 5 of the radius R of the value.

[0011] A small through hole is provided at the edge of the top surface of the single-hole circular surface rotor, and the vertical distance from the center of the circular cross-section of the through hole to the rotating shaft d The value of 2 satisfies being greater than 1 / 2 of the rotor radius R and less than the rotor radius R of the value, and the radius r of the through hole Ris 1 / 10 of and less than the rotor radius R and less than 1 / 2 of the numerical value.

[0012] The multi-tooth rotor described above is formed by arranging N elliptical top surface structures around the rotation of the rotating shaft, where N is greater than or equal to 2 and less than or equal to 12, and the rotation angle of each elliptical top surface structure around the rotating shaft is equal.

[0013] The porous circular surface rotor described above has N small through holes evenly distributed near the edge of the top surface, where N is greater than or equal to 2 and less than or equal to 12, and the vertical distance from the center of the circular cross-section of each through hole to the rotating shaft d 2 is equal.

[0014] The multi-tooth rotor and the porous circular surface rotor described above can make the number of teeth or holes passed by the laser within the same time change in multiples, thereby increasing the rotation speed measurement range of the laser type tachometer.

[0015] During measurement, the incident laser is perpendicular to the top surface of the rotor, the height is flush with the height of the central axis of the rotating shaft, and the horizontal distance from the center of the rotating shaft d is within the following range: For the elliptical top surface rotor and the multi-tooth rotor, it is required that this horizontal distance d is between the maximum and minimum rotation radii of the elliptical top surface rotor, that is, it satisfies d 1,min < d < d 1,max ; for the single-hole circular surface rotor and the porous circular surface rotor, it is required that the laser can pass through the through hole on the single-hole circular surface rotor or the porous circular surface rotor, that is, the horizontal distance d satisfies d 2 - r < d < d 2 + r .

[0016] The extension line of the laser emitted by the tachometer to be calibrated passes through the smooth cut surface of the cutting smooth block. When the laser passes through the top surface of the rotor, the incident laser returns along the original path and the signal is received by the tachometer. When the laser does not pass through the top surface of the rotor, the reflected laser is reflected by the cutting smooth block to other directions, so that no interference signal that can be received by the tachometer is generated.

[0017] During one rotation of the elliptical top surface rotor or the single-hole circular surface rotor, the returned laser signal received by the tachometer is interrupted only once, and the standard rotation speed n0 is the set rotation speed n s;During one rotation of the multi-tooth rotor or the porous circular surface rotor, since there are N tooth-shaped protrusions on the top surface edge of the multi-tooth rotor and N through holes on the porous circular surface rotor, the returned laser signal received by the rotational speed measuring instrument will have sub-pulses. Therefore, the standard rotational speed n0 at this time = the set rotational speed n s ×N.

[0018] The beneficial effects of the present invention are as follows: By changing the shape of the rotor, during one complete rotation of the rotor, the reflection signal of the laser on it stably changes continuously once or multiple times, completing the generation of the main signal. At the same time, a smooth cutting block is designed behind the rotor to eliminate background noise, enabling the laser sensor to receive an effective signal with regular changes. Then, through the data analysis system of the laser rotational speed measuring instrument, a stable reading is generated, completing the verification or calibration of the laser rotational speed measuring instrument. The present invention is applied to the metrology and testing industry, which can improve the detection efficiency and detection accuracy of the laser rotational speed measuring instrument. Description of the Drawings

[0019] Figure 1 is a schematic diagram of the overall assembly structure of the present invention.

[0020] Figure 2 is a schematic diagram of the elliptical top surface rotor structure adopted by the present invention.

[0021] Figure 3 is a schematic diagram of the single-hole circular surface rotor structure adopted by the present invention.

[0022] Figure 4 is a schematic diagram of the multi-tooth rotor structure adopted by the present invention.

[0023] Figure 5 is a schematic diagram of the porous circular surface rotor structure adopted by the present invention.

[0024] Figure 6 is a schematic diagram of the structure of the smooth cutting block in the present invention.

[0025] Figure 7 is a schematic diagram of the optical path of the present invention during the detection process.

[0026] In the figure: 1. Base; 2. Rotating shaft; 3. Rotor; 4. Slide groove; 5. Smooth cutting block; 6. Elliptical top surface rotor; 7. Single-hole circular surface rotor; 8. Multi-tooth rotor; 9. Porous circular surface rotor; 10. Smooth cutting surface; 11. Card slot. Detailed Embodiments

[0027] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0028] According to the attached Figure 1 ~Attached Figure 7, the present invention is a calibration device for a laser rotational speed measuring instrument, including a rotational speed generating device. The rotational speed generating device includes a base 1 at the bottom, a rotor 3 above the base 1 connected to the built-in engine of the rotational speed generating device, and a smooth cutting block 5 disposed beside the rotor 3. The processing of the laser signal is achieved through the cooperation between the rotation of the rotor 3 and the smooth cutting block 5. The rotor 3 is designed as a detachable structure and is fixedly installed on the rotating shaft 2 of the built-in engine of the rotational speed generating device through a bayonet or screws, and the two rotate coaxially. The rotating shaft 2 drives the rotor 3 to rotate at a set rotational speed through the operation of the built-in engine. The smooth cutting block 5 has a smooth cutting surface 10 for reflecting the laser on one side and a card slot 11 on the back, which is matched and installed with the sliding groove 4 provided on the rotational speed generating device and realizes sliding movement in the direction of approaching or departing from the rotor 3. The position of the smooth cutting block 5 is horizontally slid and positioned along the sliding groove 4 according to the laser incident point, and the horizontal center line of the sliding groove 4 is basically at the same height as the axis of the rotating shaft 2.

[0029] According to the attached Figure 2 ~Attached Figure 5 , the rotor 3 is divided into an elliptical top surface rotor 6 with eccentric installation, a circular top surface rotor with centered installation, and a multi-tooth rotor 8 according to the installation method with the rotating shaft 2. The circular top surface rotor is divided into a single-hole circular surface rotor 7 and a multi-hole circular surface rotor 9. The rotor 3 can correspondingly modulate the laser signal into a positive-polarity pulse signal and a negative-polarity pulse signal, so that the signal shows different duty cycles. The inspector can select to use the elliptical top surface rotor 6, the multi-tooth rotor 8, the single-hole circular surface rotor 7, or the multi-hole circular surface rotor 9 according to the type of the internal signal processor of the measured laser rotational speed measuring instrument.

[0030] 1. Elliptical top surface rotor 6: According to the attached Figure 2 , the elliptical top surface rotor 6 requires that the maximum value of the perpendicular distance from each point on the edge of the top surface to the rotating shaft 2 d 1,max and the minimum value d 1,min are not equal, where: d 1,max must be less than the perpendicular distance from the rotating shaft 2 to the base 1, and it is recommended that d 1,min ≤2 / 3 d 1,max , the rotation axis of the elliptical top surface rotor 6 should deviate from the center of the elliptical surface, and its top surface thickness t 1 satisfies 1 / 10 d 1,max ≤ t 1≤1 / 5 d 1,max , to avoid deformation of the top surface of the elliptical top surface rotor 6 due to too small thickness, or damage to the rotating shaft 2 caused by too large dynamic eccentricity moment due to too large thickness.

[0031] 2. Multi-tooth rotor 8, single-hole circular surface rotor 7, and multi-hole circular surface rotor 9: The radius of these rotors R shall be less than the vertical distance from the rotating shaft 2 to the base 1, and the thickness t 2 satisfies 1 / 10 R ≤ t 2 ≤ 1 / 5 R . According to the appendix Figure 3 , a small through hole is provided near the edge of the top surface of the single-hole circular surface rotor 7. The vertical distance from the center of the through hole to the rotating shaft 2 d 2 satisfies 1 / 2 R < d 2 < R , and the radius of the through hole r satisfies 1 / 10 R ≤ r < 1 / 2 R ; According to the appendix Figure 4 , the multi-tooth rotor 8 is formed by rotating and arranging N (2 ≤ N ≤ 12) elliptical top surface structures around the rotating shaft 2, and is distributed in a petal shape. The rotation angle of each elliptical top surface structure around the rotating shaft 2 is equal; According to the appendix Figure 5 , the multi-hole circular surface rotor 9 is evenly distributed with N (2 ≤ N ≤ 12) small through holes near the edge of the top surface. The vertical distance from the center of each through hole to the rotating shaft 2 d 2 is equal. The multi-tooth rotor 8 and the multi-hole circular surface rotor 9 can make the number of teeth or holes passed by the laser within the same time change in multiples, thereby increasing the rotation speed measurement range of the laser type rotation speed measuring instrument.

[0032] According to the appendix Figure 7 , the specific operation steps of the present invention are as follows: 1. Place the base 1 of the rotation speed generating device on a horizontal tabletop, and fix the selected rotor 3 on the rotating shaft 2.

[0033] 2. Adjust the position of the laser type rotation speed measuring instrument to be calibrated so that the incident laser is perpendicular to the top surface of the rotor 3, and the height is flush with the height of the central axis of the rotating shaft 2. The horizontal distance from the center of the rotating shaft 2 d is within the following range: For the elliptical top surface rotor 6 and the multi-tooth rotor 8, it is required that this horizontal distance d is between the maximum and minimum rotation radii of the elliptical top surface rotor 6, that is, it satisfies d 1,min < d < d 1,max ; For the single-hole circular surface rotor 7 and the multi-hole circular surface rotor 9, it is required that the laser can pass through the through hole on the single-hole circular surface rotor 7 or the multi-hole circular surface rotor 9, that is, the horizontal distance d satisfies d 2 - r <d < d 2+ r 。

[0034] 3. Move the smooth cutting block 5 so that the extension line of the laser emitted by the tachometer to be calibrated passes through the smooth cutting surface 10. Then, when the laser passes through the top surface of the rotor 3, it will return along the incident line a in the attachment Figure 7 and the signal will be received by the tachometer; when the laser does not pass through the top surface of the rotor 3, it will be reflected by the smooth cutting block 5 behind the rotor 3 along the reflection line b in the attachment Figure 7 to other directions, so that no interference signal that can be received by the tachometer will be generated.

[0035] 4. According to the requirements of the verification regulation or calibration specification, set the rotational speed n through the controller of the rotational speed generating device s 。

[0036] During one revolution of the elliptical top surface rotor 6 or the single-hole circular surface rotor 7, the returned laser signal received by the tachometer is interrupted only once, and the standard rotational speed n0 is the set rotational speed n s ; during one revolution of the multi-tooth rotor 8 or the multi-hole circular surface rotor 9, since there are N tooth-shaped protrusions on the edge of the top surface of the multi-tooth rotor 8 and N through holes on the multi-hole circular surface rotor 9, the returned laser signal received by the tachometer will have N pulses. Therefore, the standard rotational speed n0 at this time = the set rotational speed n s ×N.

[0037] 5. Continuously read and record 3 rotational speed readings of the tachometer to be calibrated, and take the average value and compare it with the standard rotational speed n0 to calculate the corresponding indication error.

[0038] 6. Adjust the set rotational speed and repeat steps 4 to 5 until the test is completed.

[0039] The above steps take the verification process of the rotational speed indication error as an example, and other verification and calibration items related to the rotational speed indication (repeatability, measurement range, etc.) can be inferred by analogy.

Claims

1. A calibration device for a laser type rotational speed measuring instrument, characterized in that: It includes a rotational speed generating device. The rotational speed generating device includes a base at the bottom, a rotor above the base connected to the built-in engine of the rotational speed generating device, and a cutting smooth block disposed beside the rotor. The processing of the laser signal is achieved through the mutual cooperation of the rotation of the rotor and the cutting smooth block. The rotor is fixedly installed on the rotating shaft of the built-in engine of the rotational speed generating device. The rotating shaft drives the rotor to rotate at a set rotational speed through the operation of the built-in engine. The surface of the cutting smooth block for reflecting the laser is a smooth cutting surface, and a card slot is provided on the back, which is matched and installed with the sliding groove provided on the rotational speed generating device and is slidably connected in a direction approaching or departing from the rotor.

2. The calibration device for a laser type rotational speed measuring instrument according to claim 1, wherein: The rotor is designed with a detachable structure and is fixedly installed on the rotating shaft through a bayonet or screws, and the two rotate coaxially.

3. A calibration device for a laser rotational speed measuring instrument according to claim 1, characterized in that: The position of the cutting smooth block is horizontally slid and positioned along the sliding groove according to the laser incident point, and the horizontal center line of the sliding groove is at the same height as the axis of the rotating shaft.

4. A calibration device for a laser type rotational speed measuring instrument according to claim 1, characterized in that: According to the installation method with the rotating shaft, the rotor is divided into an elliptical top surface rotor with eccentric installation, a circular top surface rotor with centered installation, and a multi-tooth rotor. The circular top surface rotor is divided into a single-hole circular surface rotor and a multi-hole circular surface rotor, and the corresponding rotor is selected according to the type of the internal signal processor of the measured laser type tachometer.

5. A calibration device for a laser type rotational speed measuring instrument according to claim 4, characterized in that: The maximum perpendicular distance from each point on the top surface edge of the elliptical top surface rotor to the rotating shaft d 1,max and the minimum value d 1,min are not equal, where: the maximum value d 1,max must be less than the perpendicular distance from the rotating shaft to the base, and the top surface thickness of the elliptical top surface rotor t The value satisfies being greater than or equal to 1 / 10 of the maximum value d 1,max and less than or equal to 1 / 5 of the maximum value d 1,max of the value.

6. A calibration device for a laser type rotational speed measuring instrument according to claim 4, characterized in that: Radius of multi-tooth rotor, single-hole circular surface rotor and multi-hole circular surface rotor R shall be less than the vertical distance from the rotating shaft to the base, and the thickness t The value of 2 satisfies being greater than or equal to 1 / 10 of the radius R and less than or equal to 1 / 5 of the radius R value.

7. A calibration device for a laser type rotational speed measuring instrument according to claim 6, characterized in that: The single-hole circular surface rotor is provided with a small through hole near the edge of the top surface, and the vertical distance from the center of the circular cross-section of the through hole to the rotating shaft d The value of 2 satisfies being greater than 1 / 2 of the rotor radius R and less than the value of the rotor radius R The radius of the through hole r The value of satisfies being greater than or equal to 1 / 10 of the rotor radius R and less than 1 / 2 of the value of the rotor radius R The value of.

8. A calibration device for a laser type rotational speed measuring instrument according to claim 6, characterized in that: The multi-tooth rotor is formed by arranging N elliptical top surface structures around the rotating shaft in a rotating manner, where N is greater than or equal to 2 and less than or equal to 12, and the rotation angle of each elliptical top surface structure around the rotating shaft is equal.

9. The calibration device for a laser type rotational speed measuring instrument according to claim 6, characterized in that: The described porous circular surface rotor is evenly distributed with N small through holes near the edge of the top surface, where N is greater than or equal to 2 and less than or equal to 12, and the vertical distance from the center of the circular cross-section of each through hole to the rotating shaft d is equal.

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