Deformation detection device applied to fan main shaft

Abstract

The utility model provides a deformation detection device applied to a fan main shaft, which comprises an emitting light path and a receiving light path which meet the Sammer condition, laser emitted by the emitting light path is incident to a detected target surface and is received by the receiving light path after being reflected by the detected target surface, and a lens is a collimating lens; the receiving light path comprises a receiving lens, a reflecting lens and a linear image sensor CMOS (Complementary Metal-Oxide-Semiconductor Transistor), reflected light of a measured target surface passes through the receiving lens and then enters the reflecting lens, and the reflecting lens reflects required wavelength to the linear image sensor CMOS through useless wavelength. According to the utility model, through the design of the cutoff wave band of the reflecting mirror, the coating cost is greatly saved, and the extreme application conditions of the wind power industry can be met.

Description

Technical Field

[0001] The utility model relates to the field of wind power, in particular to a deformation detection device applied to a main shaft of a wind turbine. Background Art

[0002] In wind power equipment, the health status of the main shaft is usually reflected by detecting the deformation of the wind turbine main shaft. When the main bearing is fatigued and deformed, the axial displacement will change. The sensor feeds back the displacement signal to the wind turbine main control in real time, monitors the active force displacement state in real time, and warns of excessive displacement in advance to ensure the safe operation of the wind turbine. Due to the harsh operating conditions in the wind power field, the sensor needs to have high environmental adaptability, high precision, and adapt to complex target surfaces.

[0003] In the prior art, in order to reduce the interference of ambient light, it is necessary to filter out light of unnecessary wavelengths. The usual solution is to coat the receiving lens with a cutoff film (to reflect ambient light) and an anti-reflection film (to transmit laser light). However, since the wavelength of ambient light is very wide, it is difficult to design the corresponding film layer and the cost is extremely high. Utility Model Content

[0004] In order to solve the problems of the prior art, the utility model provides a deformation detection device applied to a wind turbine main shaft, which greatly saves the cost of coating through the cut-off band design of the reflector and can meet the extreme application conditions of the wind power industry.

[0005] The utility model provides a deformation detection device applied to a main shaft of a fan, comprising an emitting light path and a receiving light path satisfying the Sham condition, wherein the laser emitted by the emitting light path is incident on a target surface to be measured, and is received by the receiving light path after being reflected by the target surface to be measured, and the lens is a collimating lens; the receiving light path comprises a receiving lens, a reflecting lens and a linear image sensor CMOS, and the reflected light of the target surface to be measured is incident on the reflecting lens after passing through the receiving lens, and the reflecting lens transmits useless wavelengths and reflects required wavelengths to the linear image sensor CMOS.

[0006] As a further improvement, the emission light path uses a semiconductor laser with a wavelength of 655±10nm, and the reflective lens is coated with a film layer with a cutoff band of 640-670nm.

[0007] As a further improvement, the emission light path includes a semiconductor laser and a lens, and the laser light emitted by the semiconductor laser is shaped by the lens and then incident on the target surface to be measured.

[0008] As a further improvement, the lens is a glass aspheric collimating lens. In order to reduce the influence of stray light on the sensor accuracy and facilitate assembly with mechanical parts, the edge of the collimating lens is designed to be a plane, and ink is applied on the plane.

[0009] As a further improvement, the focal length of the receiving lens ranges from 35 to 40 mm, and the path length of the optical path between the linear image sensor CMOS and the receiving lens (the sum of the distances from the light passing through the receiving lens to the reflector and the distance from the reflector to the CMOS) ranges from 53 to 67 mm.

[0010] For further improvement, the angle between the optical axis of the receiving light path and the optical axis of the transmitting light path should not be too large, and can be selected between 8 and 20 degrees.

[0011] A further improvement is that the receiving lens angle is on the bisector of the field of view angle.

[0012] The beneficial effects of the utility model are:

[0013] 1. Through the design of the cut-off band of the reflector, the required wavelength is reflected (cut-off laser) and the useless wavelength is transmitted (through ambient light) to achieve the purpose of filtering out stray light, which greatly saves the cost of coating.

[0014] 2. A glass aspheric collimating lens is selected as the emission light path lens to obtain good beam quality, longer Rayleigh distance, and meet the extreme application conditions of the wind power industry. In order to reduce the impact of stray light on sensor accuracy and facilitate assembly with mechanical parts, a plane is designed at the edge of the collimating lens and the plane is coated with ink.

[0015] 3. The angle of the receiving lens is on the bisector of the field of view to reduce the large distortion caused by off-axis light. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 Design schematic for optical path.

[0018] Figure 2 Schematic diagram of the collimating lens structure.

[0019] Figure 3 Schematic diagram of the receiving optical path.

[0020] Figure 4 Schematic diagram of the reflection cutoff band.

[0021] Figure 5 Schematic diagram of the linear image sensor CMOS structure. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] The overall principle of the utility model is as follows Figure 1 As shown, it includes a transmitting light path and a receiving light path that meet the Sham condition. The laser emitted by the transmitting light path is incident on the target surface to be measured, and is received by the receiving light path after being reflected by the target surface to be measured.

[0024] In order to obtain good beam quality, longer Rayleigh distance, and can be used in extreme application conditions of the wind power industry, the lens of the emission light path of the utility model is selected as a glass aspheric collimating lens, which is different from conventional products on the market. In order to reduce the influence of stray light on the accuracy of the sensor and facilitate assembly with mechanical parts, the edge of the collimating lens is designed to be flat and the flat surface is painted with ink, such as Figure 2 shown.

[0025] Receiving optical path Figure 3 As shown, it includes a receiving lens 1, a reflecting lens 2 and a linear image sensor CMOS 3. The reflected light of the target surface is incident on the reflecting lens after passing through the receiving lens. The reflecting lens transmits useless wavelengths and reflects the required wavelengths to the linear image sensor CMOS.

[0026] In order to reduce the interference of ambient light, it is necessary to filter out the light of unnecessary wavelengths. The usual solution is to coat the receiving lens with a cut-off film (to reflect ambient light) and an anti-reflection film (to transmit laser light). However, since the wavelength of ambient light is very wide, it is difficult to involve the corresponding film layer and the cost is extremely high.

[0027] The utility model designs a reflector, which reflects the required wavelength (cuts off the laser) and transmits the useless wavelength (passes the ambient light) to achieve the purpose of filtering out stray light.

[0028] According to the selection of 655±10nm wavelength semiconductor laser at the transmitting end, a film layer with a cutoff band of 640-670nm is designed, such as Figure 4 shown.

[0029] Figure 5 This is a schematic diagram of the linear image sensor CMOS structure. Rectangular photosensitive pixels are arranged linearly on the substrate. The smaller the pixel, the higher the measurement accuracy. The linear image sensor selected in this patent has a pixel size of only 5.5um, which is the smallest pixel size CMOS used in industry.

[0030] The receiving optical path angle in the utility model is designed as follows:

[0031] refer to Figure 3 The receiving lens angle should be as close as possible to the bisector of the field of view angle to reduce the large distortion caused by off-axis light.

[0032] In the figure, AC is the measurement range. Through calculation, we can get the relationship between the field angle ∠AOC, focal length f and imaging interval ac:

[0033] (1)

[0034] In the figure, u is the object distance; v is the image distance; and f is the focal length of the lens.

[0035] If the CMOS size is 8mm, the length of a'c' should be less than 8mm. And the measurement range is 90~110mm, so the focal length of the receiving lens is selected to be between 35~40mm, and the path length of the optical path between the CMOS and the receiving lens (the sum of the distance from the receiving lens to the reflector and the distance from the reflector to the CMOS) is calculated to be between 53~67mm.

[0036] To reduce the difficulty of installation, the CMOS position of the receiving system cannot be adjusted. Therefore, it is necessary to ensure that the light spots at all positions within the measured range can be clearly imaged on the CMOS during design. The size of the CMOS receiving surface is selected according to the imaging range, and the angle between the CMOS and the axis of the receiving optical path is calculated to ensure that the size of the structure is not too large and the imaging is clear. The angle between the optical axis of the receiving optical path and the optical axis of the transmitting optical path should not be too large, and can be selected between 8 and 20 degrees. Considering that the selected CMOS size is 8mm, the corresponding system requires a field of view angle between 1.58 and 3.69 degrees.

[0037] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred implementation of the utility model. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited to this. Any technician familiar with the technical field is within the technical scope disclosed by the utility model. For ordinary technicians in the technical field, changes or replacements that can be easily thought of should be included in the protection scope of the utility model without departing from the principle of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A deformation detection device for a fan main shaft, comprising a transmitting optical path and a receiving optical path satisfying the Sham condition, wherein the laser emitted by the transmitting optical path is incident on a target surface to be measured, and is received by the receiving optical path after being reflected by the target surface to be measured, and is characterized in that: The transmitting optical path includes a semiconductor laser and a lens. The laser emitted by the semiconductor laser is shaped by the lens and then incident on the target surface to be measured. The lens is a collimating lens. The receiving optical path includes a receiving lens, a reflecting lens and a linear image sensor CMOS. The reflected light from the target surface to be measured passes through the receiving lens and then enters the reflecting lens. The reflecting lens transmits useless wavelengths and reflects required wavelengths to the linear image sensor CMOS.

2. The deformation detection device for a fan main shaft according to claim 1 is characterized in that: The emission light path uses a semiconductor laser with a wavelength of 655±10nm, and the reflective lens is coated with a film layer with a cutoff band of 640-670nm.

3. The deformation detection device for a fan main shaft according to claim 1 is characterized in that: The lens is a glass aspherical collimating lens.

4. The deformation detection device for a fan main shaft according to claim 3 is characterized in that: The edge of the collimating lens is designed to be a plane, and ink is applied on the plane.

5. The deformation detection device applied to the fan main shaft according to claim 1 is characterized in that: The focal length of the receiving lens ranges from 35 to 40 mm, and the path length of the optical path between the linear image sensor CMOS and the receiving lens ranges from 53 to 67 mm.

6. The deformation detection device for a fan main shaft according to claim 1 is characterized in that: The angle between the receiving light path optical axis and the transmitting light path optical axis is 8-20°.

7. The deformation detection device for a fan main shaft according to claim 1 is characterized in that: The receiving lens angle is on the bisector of the field of view angle.

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