CN217930170U - An Optical Detection Type Spindle Rotation Error Measuring Device - Google Patents

Abstract

The utility model discloses an optical detection type spindle rotation error measuring device. The measuring device includes a laser interferometer, a first corner mirror, a second corner mirror and a first beam splitter. The laser interferometer, the first beam splitter and the second pyramid reflector are arranged in sequence along the axial direction of the measured main shaft. During the measurement process, the second pyramid reflector is coaxially and fixedly installed at the end of the measured spindle. The first corner mirror is mounted on the side of the first beam splitter. The utility model is equipped with a cone-angle reflector at the end of the main shaft, and uses the principle of laser interference to measure the axial error of the main shaft to achieve high-precision measurement. Only high requirements are placed on the accuracy of the optical device, and the requirements on the processing accuracy and installation accuracy of the detection installation part lower. In addition, the utility model only adds a group of optical mirrors and PSD sensors on the basis of axial detection, and realizes radial error detection synchronously without adding additional light sources.

Description

An Optical Detection Type Spindle Rotation Error Measuring Device

technical field

The utility model belongs to the field of spindle rotation error measurement in the precision measurement technology, in particular to a device for simultaneously detecting spindle axial, radial and inclination errors by using a laser interferometer, a PSD sensor and a laser autocollimator.

Background technique

The accuracy of the machine tool determines the accuracy of the machined parts to a large extent. In order to ensure the processing quality of mechanical products, it is an inevitable trend for machine tools to develop to high precision. The spindle is the core component of the CNC machine tool, and its rotation error is an important factor affecting the machining accuracy of the machine tool. Experimental studies have shown that: in precision machining, the spindle rotation error accounts for 30% to 70% of the total error ratio, and the higher the accuracy level of the machine tool, the larger the spindle rotation error accounts for the total error ratio. The measurement of rotation error has very important practical significance for evaluating the accuracy of the machine tool spindle, monitoring the running state of the spindle, and discovering and diagnosing the fault of the spindle in time.

At present, there are many methods for measuring the rotation error of the spindle. The commonly used measurement method is to use the standard bar error separation method, and use one-dimensional displacement sensors such as capacitive and eddy current sensors to measure the error motion of the spindle. However, standard rods are required in the measurement, which increases the manufacturing cost and difficulty, and requires error separation. Some scholars have proposed a tracking method based on optical target marking traces to measure the spindle rotation error, but this method is only sensitive to radial errors, and it is difficult to measure other errors.

Utility model content

The purpose of the utility model is to propose an optical detection type spindle rotation error measuring device.

The utility model provides an optical detection type spindle rotation error measuring device, which comprises a laser interferometer, a first pyramid reflector, a second pyramid reflector and a first spectroscope. The laser interferometer, the first beam splitter and the second pyramid reflector are arranged in sequence along the axial direction of the measured main shaft. During the measurement process, the second pyramid reflector is coaxially and fixedly installed at the end of the measured spindle. The first corner mirror is mounted on the side of the first beam splitter.

During the measurement process, the incident laser light emitted by the laser interferometer passes through the first beam splitter and enters the second corner mirror. The incident laser light forms the first sub-beam at the first beam splitter; the first sub-beam re-enters the first beam splitter after being reflected by the first corner cone reflector, and is then directed to the detection of the laser interferometer after being reflected by the first beam splitter area. The incident laser light is reflected by the second pyramid reflector to form a reflected beam; the reflected beam shoots to the detection area of the laser interferometer. The first sub-beam is used as standard light, and the reflected beam is used as test light to form interference fringes in the detection area of the laser interferometer.

Preferably, the laser interference-based spindle rotation error measurement device further includes a second beam splitter and a PSD sensor. The second beam splitter is arranged between the laser interferometer and the second corner mirror. The PSD sensor is disposed on the side of the second beam splitter. During the test, the reflected light beam forms a second sub-beam at the second beam splitter; the second sub-beam enters the PSD sensor.

Preferably, the spindle rotation error measurement device based on laser interference further includes a ring plane mirror and a laser autocollimator. The annular plane mirror is fixed on the measured spindle. The laser autocollimator is installed on the frame, and is vertically facing the mirror surface of the annular plane mirror.

Preferably, the coating directions of the first beamsplitter and the second beamsplitter form an included angle of 45° with the laser emission direction of the laser interferometer.

Preferably, the reflective surface of the second retroreflector is conical with a cone angle of 90°.

Preferably, the reflective surface of the first pyramid reflector is in the shape of a right angle L or a cone with a cone angle of 90°.

Preferably, the laser emission direction of the laser interferometer does not coincide with the axis of the measured spindle.

As preferably, in the measurement process, the distance between the straight line where the first sub-beam is incident on the part of the first retroreflector and the tip of the first retroreflector is equal to the straight line where the incident laser is located and the tip of the second retroreflector in the initial state the distance.

The beneficial effect that the utility model has:

1. The utility model is equipped with a cone-angle reflector at the end of the main shaft, and uses the principle of laser interference to measure the axial error of the main shaft. The realization of high-precision measurement only has high requirements for the accuracy of optical devices, and the processing accuracy and installation accuracy of the detection installation part The requirements are low, and there is no need to control factors such as surface accuracy, roughness, and spindle material.

2. The utility model only adds a group of optical mirrors and PSD sensors on the basis of axial detection, and realizes radial error detection synchronously without adding additional light sources, which reduces equipment costs and simplifies operations, and Additional errors caused by asynchronous error detection are avoided.

3. While detecting the axial and radial errors, the utility model uses the annular reflector and the laser autocollimator to detect the inclination error synchronously.

Description of drawings

Fig. 1 is the overall optical path schematic diagram of the measuring device that the utility model adopts;

Fig. 2 is a schematic diagram of installation of the utility model spindle plane mirror;

Fig. 3 is a measurement principle diagram of the laser autocollimator adopted in the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

As shown in Figure 1, an optical detection type spindle rotation error measurement device includes a laser interferometer, a first corner mirror a, a second corner mirror b, a first beam splitter 1, a second beam splitter 2, a PSD sensor, annular plane mirror c and laser autocollimator 3.

The laser interferometer, the first beam splitter 1, the second beam splitter 2, and the second corner mirror b are arranged in sequence along the axial direction of the main axis to be measured. The laser interferometer, the first beam splitter 1 and the second beam splitter 2 are all installed on the frame; during the measurement process, the second corner mirror b is fixed coaxially on the end of the main shaft. The mirror direction of the second corner mirror b faces the laser interferometer.

The reflective surface of the first pyramid reflector a is in the shape of a right angle L. The reflective surface of the second corner mirror b is conical, and the cone angle is 90°; the coating directions of the first beam splitter 1 and the second beam splitter 2 are both at an angle of 45° to the axial direction of the measured spindle.

The first corner mirror a is installed on the side of the first beam splitter 1 . The PSD sensor is installed on the frame, below the second beam splitter 2 perpendicular to the axis, so that the reflected light of the second beam splitter 2 can hit the PSD sensor.

The reflective surface of the first cube reflector a is installed opposite to the coating of the first beam splitter 1, so that the light reflected by the first beam splitter 1 is reflected by the first cube mirror a and enters perpendicular to the initial laser incident direction On the coating of the first beam splitter 1.

During the test, the incident laser light emitted by the laser interferometer passes through the first beam splitter 1 and the second beam splitter 2 and enters the second corner mirror b. The incident laser light forms the first sub-beam at the first beam splitter 1; the first sub-beam is reflected by the first corner mirror a and then re-enters the first beam splitter 1, and is reflected by the first beam splitter 1 and then shoots to the laser The detection area of the interferometer.

The incident laser beam is reflected at the second corner mirror b to form a reflected beam; the reflected beam passes through the second beam splitter 2 and the first beam splitter 1 to the detection area of the laser interferometer; the reflected beam forms a second beam at the second beam splitter 2 A sub-beam; the second sub-beam enters the PSD sensor. The first sub-beam is used as standard light, and the reflected beam is used as test light to form interference fringes in the detection area of the laser interferometer.

The incident laser does not coincide with the axis of the measured spindle. The distance between the straight line where the first sub-beam is incident on the part of the first retroreflector a and the tip of the first retroreflector a is equal to the distance between the straight line where the incident laser is located and the tip of the second retroreflector b in the initial state, so that The position where the first sub-beam is incident on the detection area of the laser interferometer is the same as or close to that of the reflected beam.

The part of the first sub-beam passing through the first beam splitter 1, the sub-beam of the incident laser beam reflected by the second beam splitter 2, and the sub-beam of the reflected beam reflected by the first beam splitter 1 are not directed to any part of the measuring device. Components do not play any role and do not affect the test results, so they will not be described in detail.

The annular plane mirror c is coaxially fixed on the outer peripheral surface of the measured main shaft. While ensuring the surface quality of the annular plane mirror c, it is necessary to ensure the perpendicularity between the mirror surface of the plane mirror and the axis of the main shaft. The laser autocollimator 3 is installed on the frame, and faces the mirror surface of the annular plane mirror c, and is used for emitting and receiving laser light.

The working principle of the utility model is as follows:

Step 1. Install the first beam splitter 1 and the second beam splitter 2 in combination, keep the beam splitting planes of the first beam splitter 1 and the second beam splitter 2 parallel to each other, and form an angle of 45° with the axial direction of the measured spindle, To ensure the accuracy of optical path measurement; the first corner mirror a is installed on the top of the first beam splitter 1 to form standard light; the second corner mirror b is installed at the center of the spindle end face to generate experimental light. A PSD sensor is installed on the side of the second beam splitter 2 to receive the light reflected by the second beam splitter 2 and to obtain the radial error of the main shaft. When installing, the center is aligned with the optical path to ensure the utilization of the PSD sensor and prevent Omission of light signals.

Step 2: Run the measured spindle, and the measured spindle drives the second corner mirror b to rotate; after the motion is stable, run the laser interferometer; the laser emitted by the laser interferometer is divided into two beams by the first beam splitter 1, one The beam is reflected at the first beam splitter 1, and returns to the laser interferometer under the secondary reflection of the first corner mirror a and the first beam splitter 1. This beam of light is a standard light; while the other beam is After passing through the first beam splitter 1, after being reflected by the second pyramid reflector b installed at the main axis of the test, it also returns to the laser interferometer. This beam of light is the experimental light. The laser light is separated, so the two meet the coherent condition, and then interfere.

Due to the axial displacement of the main shaft during the movement of the main shaft, that is, the existence of axial errors, the interference fringes between the two beams of light will change with the rotation of the main shaft; A laser wavelength, there will be a cycle of interference fringe light intensity changes (bright-dark-bright). By calculating this change, the axial error of the main shaft can be solved. This part is used to measure the axial error of the main shaft. Detection module part1.

其中，λ₀为激光波长；n为空气折射率。Specifically, the optical path of the test light changes with the axial movement of the main shaft, and the number of interference fringes also changes with the optical path of the test light. From this, the axial error of the measured spindle can be calculated by the change amount N _θ of the number of interference fringes relative to the initial time

Among them, λ ₀ is the laser wavelength; n is the refractive index of air.

Step 3. After the experimental light is acted on by the second corner mirror b installed at the main axis, it will be affected by the second beam splitter 2 on the way back to the receiving end of the laser interferometer; the experimental light will be affected by the second beam splitter 2 The lower beam is divided into two beams, one beam of light is directly transmitted through the beam splitter, and returns to the detection area of the laser interferometer; the other beam of light is reflected at the second beam splitter 2, and then changes the optical path and projects to the side of the second beam splitter 2 part of the PSD sensor. Since the radial movement of the main shaft will change the incident point of the laser at the second corner mirror b, so that the position of its exit point will also change, so the laser incident position signal detected by the PSD sensor will also change, to be measured When the main shaft is at different phases θ, the spot position signal and initial position signal detected by the PSD sensor are the vectors of the end point and starting point respectively, which are the radial errors of the measured main shaft at different phase θ. This part is the radial detection module part2 used to measure the radial error of the spindle.

The principle of this process is: due to the geometric relationship between the optical paths, the radial displacement of the main shaft can be deduced from the position of the light spot track on the PSD sensor. When the second retroreflector b moves a certain distance along the x or y direction on the radial plane of the measured spindle, the light spot on the PSD sensor also moves the same distance along the x or y direction of the PSD plane.

Step 4: Solve the error of the inclination angle of the main shaft. The process of using the laser autocollimator 3 to measure the inclination error is shown in Figure 3; the laser light emitted by the laser autocollimator 3 returns to the detection area of the laser autocollimator 3 after being reflected by the annular plane mirror c. When the annular plane mirror c rotates with the main shaft, the inclination error of the main shaft will be reflected on the mirror surface, so that the landing point of the beam received by the laser autocollimator 3 will be shifted. Through this principle, the inclination error of the main shaft can be solved. This part is the inclination detection module part3 used to measure the inclination error of the main shaft.

As an optional implementation, the following formula can be used to calculate the inclination error of the main shaft in the X and Y directions:

分别为环形平面镜c的安装误差

在x方向、y方向的分量。Among them, α _θ (x), α _θ (y) are the components of the spindle inclination angle error α _θ in the x direction and y direction, respectively; γ _θ (x), γ _θ (y) are the autocollimator readings γ _θ in Components in the x direction and y direction;

Respectively, the installation error of the annular plane mirror c

Components in the x-direction and y-direction.

Claims (8)

1. An optical detection formula main shaft gyration error measuring device which characterized in that: comprises a laser interferometer, a first pyramid reflector, a second pyramid reflector and a first spectroscope (1); the laser interferometer, the first beam splitter (1) and the second pyramid reflector are sequentially arranged along the axial direction of the measured spindle; in the measuring process, the second pyramid reflector is coaxially and fixedly arranged at the end part of the measured main shaft; the first angle cone reflector is arranged on the side part of the first spectroscope (1);

in the measuring process, incident laser emitted by the laser interferometer is emitted into the second pyramid reflecting mirror through the first beam splitter (1); incident laser forms a first split beam at a first beam splitter (1); the first light beam is reflected by the first angle cone reflector and then re-enters the first light splitter (1), and is reflected by the first light splitter (1) and then is emitted to the detection area of the laser interferometer; the incident laser is reflected on the second pyramid reflector to form a reflected beam; the reflected light beam is emitted to the detection area of the laser interferometer; the first split beam is used as standard light, the reflected beam is used as test light, and interference fringes are formed in a detection area of the laser interferometer.

2. An optical detection type spindle gyration error measuring apparatus according to claim 1, characterized in that: the device also comprises a second spectroscope (2) and a PSD sensor; the second beam splitter (2) is arranged between the laser interferometer and the second pyramid reflector; the PSD sensor is arranged on the side part of the second spectroscope (2); during the test, the reflected light beam forms a second split beam at the second beam splitter (2); the second split beam is incident on the PSD sensor.

3. An optical detection type spindle gyration error measuring apparatus according to claim 2, wherein: the laser collimator also comprises an annular plane mirror and a laser autocollimator; the annular plane mirror is fixed on the measured main shaft; the laser autocollimator is mounted on the frame and faces the mirror surface of the annular plane mirror vertically.

4. An optical detection type spindle revolution error measuring device according to claim 2, characterized in that: the coating directions of the first spectroscope (1) and the second spectroscope (2) form 45-degree included angles with the laser emitting direction of the laser interferometer.

5. An optical detection type spindle gyration error measuring apparatus according to claim 1, characterized in that: the reflecting surface of the first angle cone reflecting mirror is in a right-angle L shape or a cone shape with a cone angle of 90 degrees.

6. An optical detection type spindle gyration error measuring apparatus according to claim 1, characterized in that: the reflecting surface of the second pyramid reflector is conical with a cone angle of 90 degrees.

7. An optical detection type spindle gyration error measuring apparatus according to claim 1, characterized in that: and the laser emitting direction of the laser interferometer is not coincident with the axis of the measured spindle.

8. An optical detection type spindle revolution error measuring device according to claim 7, characterized in that: in the measuring process, the distance between the straight line of the part of the first split beam, which enters the first angle cone reflector, and the tip of the first angle cone reflector is equal to the distance between the straight line of the incident laser and the tip of the second angle cone reflector in the initial state.

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