CN117804357A - Deep hole detection device and detection method based on laser reflection - Google Patents

Abstract

The invention belongs to the field of deep hole detection, and particularly relates to a deep hole detection device and method based on laser reflection. Comprising the following steps: the device comprises a centering device, a conical surface inner reflector, a connecting rod, an annular laser emitter, a screen and an imaging device; the conical surface internal reflector and one end of the connecting rod are fixed on the central shaft of the centering device, the annular laser transmitter is fixedly arranged on the periphery of the connecting rod, the circle center of the annular laser transmitter is positioned on the axis of the centering device and is used for transmitting annular light beams to the inner wall of a deep hole of a workpiece to be detected, the annular light beams are reflected by the inner wall of the deep hole of the workpiece to be detected and then are incident to the conical surface internal reflector, parallel annular light beams are formed after being reflected by the conical surface internal reflector and are incident to the screen, and the imaging device is arranged on the other side of the screen and is used for collecting spot images on the screen; the centering device is used for automatically centering the conical surface inner reflector, the connecting rod and the annular laser emitter in the deep hole of the workpiece to be detected. The invention has simple structure and small volume, and can realize the deep hole detection with smaller diameter.

Description

Deep hole detection device and detection method based on laser reflection

Technical field

The invention belongs to the field of deep hole detection, and specifically relates to a deep hole detection device and detection method based on laser reflection.

Background technique

In machinery manufacturing, traditional measuring tools such as vernier calipers, gauges, plug gauges, and micrometers are often used for hole inspection. During inspection, the method of measuring the hole diameter is often adopted, which is to take multiple measurements of any diameter on the end face of the hole to be tested and take the average value. The three-point circle determination method is used to detect the roundness of a certain cross-section of the hole. To measure the straightness of the hole axis, a plug gauge is often used for a through test or a laser alignment instrument is used to complete the inspection on the end face of the hole. Existing optical measurement tools and equipment often have complex structures and are bulky. When faced with small apertures, they cannot penetrate deep into the hole for fixed-point measurement. Moreover, they can often only measure a single indicator. It is difficult to measure small-diameter deep holes. , contact measurement is mostly used. When the hole diameter is small to a certain extent, the detection difficulty increases greatly. Therefore, it is difficult to detect the roundness, cylindricity, and diameter inside the deep hole.

Contents of the invention

The present invention overcomes the shortcomings of the existing technology, and the technical problem to be solved is to provide a deep hole detection device and detection method with a simple structure and easy operation to achieve accurate detection of parameters related to linear deep holes.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a deep hole detection device based on laser reflection, including: a centering device, a cone internal reflector, a connecting rod, a ring laser emitter, a screen and an imaging device; One end of the conical internal reflector and the connecting rod is fixed on the central axis of the centerer, and the central axis of the conical internal reflector coincides with the central axis of the centralizer; the ring laser emitter is fixed on The outer periphery of the connecting rod, with its center located on the axis of the centering device, is used to emit an annular beam to the inner wall of the deep hole of the workpiece to be measured; after being reflected by the inner wall of the deep hole of the workpiece to be measured, the annular beam is incident on the The cone inner reflector forms a parallel annular beam after being reflected by the cone inner reflector and is incident on the screen; the imaging device is provided on the other side of the screen and is used to collect the light spot image on the screen; The centering device is used to automatically center the conical inner reflector, connecting rod, and ring laser emitter in the deep hole of the workpiece to be measured.

The deep hole detection device based on laser reflection also includes a support base, the support base is used to set the workpiece to be tested, a support rod is provided at one end of the support base, and a push rod is provided on the support rod. The push rod is used to push the centering device, the conical internal reflector and the connecting rod into the deep hole of the workpiece to be tested.

The screen and imaging device are fixedly mounted on the support base.

The connecting rod is a telescopic rod, and the telescopic rod is provided with scales, and different scales correspond to different measurement apertures.

The incident angle α of the ring laser emitted by the ring laser emitter on the inner wall of the deep hole of the workpiece to be measured and the angle 2β of the cone internal reflector satisfy the following relationship:

2β-α=90°.

The included angle 2β of the conical internal reflector satisfies the condition: 2β>120°.

The calculation unit is used to calculate the spot image collected by the imaging device (6) to obtain the deep hole aperture, and the calculation formula is:

;

in, Indicates the aperture size of the workpiece to be tested,/> Represents half of the included angle of the reflector within the cone, S represents the spot diameter of the workpiece to be measured at each circumferential position; S ₀ represents the spot diameter corresponding to the standard workpiece,/> Indicates the hole diameter of standard workpiece.

In addition, the present invention also provides a deep hole detection method based on laser reflection, which is implemented based on the deep hole detection device based on laser reflection, and includes the following steps:

Step 1: Find the standard workpiece according to the nominal aperture of the workpiece to be measured, put the deep hole detection device into the standard workpiece for measurement, obtain spot images multiple times, and calculate the average spot diameter size S ₁ in each spot image ;

Step 2: placing the deep hole detection device into the workpiece to be tested, measuring and acquiring a spot image;

Step 3: Based on the spot image, calculate the aperture size of the workpiece to be tested at multiple circumferential positions at the corresponding depth. The calculation formula is:

;

in, Indicates the hole size of the workpiece to be measured at each circumferential position,/> represents half of the included angle of the reflector within the cone, and S represents the spot diameter of the workpiece to be measured at each circumferential position;/> Indicates the hole size of the standard workpiece;

Step 4: changing the measuring depth of the deep hole detection device in the workpiece to be measured, repeating steps 2 and 3, and obtaining the spot images of the workpiece to be measured at different measuring depths and the corresponding aperture sizes.

The hole diameter of the standard workpiece is equal to the nominal hole diameter of the workpiece to be tested.

The deep hole detection method based on laser reflection also includes the steps of calculating the roundness at each measuring depth and the step of calculating the cylindricity of the workpiece to be measured;

The steps for calculating roundness are: based on the aperture size of the workpiece to be measured at each circumferential position measured at the corresponding depth, calculate the difference between the maximum value and the minimum value of the corresponding radius at each circumferential position, and obtain the radius tolerance as the corresponding measurement depth. roundness;

The steps for calculating the cylindricity are as follows: extracting the aperture sizes at various circumferential positions corresponding to a plurality of measuring depths, and calculating the corresponding radius tolerance as the cylindricity.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention provides a deep hole detection device and detection method based on laser reflection, which uses a cone internal reflector and a ring laser emitter to cooperate with each other to project the topography inside the deep hole to the outside of the deep hole, and the boundary of the spot image is The degree of clarity can also reflect the roughness of the inner wall of the deep hole; its simple structure makes the detection device very small and can detect deep holes with smaller diameters. Its data collection and processing process is simple and convenient, and it can be used in imaging images. The size of the annular light spot is calculated to obtain the specific aperture change of the deep hole, and the aperture change is amplified into the spot size change, which improves the accuracy of the measurement.

Description of drawings

Figure 1 is a schematic structural diagram of a deep hole detection device based on laser reflection provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of the measurement principle of the present invention;

In the figure: 1 is a centering device, 2 is a conical internal reflector, 3 is a connecting rod, 4 is a ring laser emitter, 5 is a screen, 6 is an imaging device, 7 is a workpiece to be measured, 8 is a supporting base, 9 is a supporting rod, and 10 is a push rod.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not All embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

Embodiment 1

As shown in Figure 1, Embodiment 1 of the present invention provides a deep hole detection device based on laser reflection, including: a centering device 1, a cone internal reflector 2, a connecting rod 3, a ring laser emitter 4, and a screen 5 and imaging device 6; one end of the conical internal reflector 2 and the connecting rod 3 is fixed on the central axis of the centerer 1, and the central axis of the conical internal reflector 2 coincides with the central axis of the centralizer 1 , the ring laser emitter 4 is fixedly arranged on the outer periphery of the connecting rod 3, and its center is located on the axis of the centering device 1, for emitting an annular beam to the inner wall of the deep hole of the workpiece 7 to be measured, and the annular beam passes through the After reflection from the inner wall of the deep hole of the workpiece 7 to be measured, it is incident on the conical inner reflector 2. After being reflected by the conical inner reflector 2, a parallel annular beam is formed and is incident on the screen 5 to form an annular light spot. The imaging device 6 is disposed on the other side of the screen 5 and is used to collect spot images on the screen 5 .

In this embodiment, the centering device 1 is used to automatically center the conical internal reflector 2, the connecting rod 3, and the ring laser emitter 4 in the deep hole of the workpiece 7 to be measured. The centering device 1 can adopt the existing centering device structure in this field.

Further, as shown in Figure 1, a deep hole detection device based on laser reflection in this embodiment also includes a support base 8. The support base 8 is used to set the workpiece 7 to be tested. One end of the support base 8 is set There is a support rod 9, and a push rod 10 is provided on the support rod 9. The push rod 10 is used to push the centerer 1, the cone internal reflector 2 and the connecting rod 3 into the deep hole of the workpiece 7 to be measured. middle.

Further, as shown in FIG. 1 , the screen 5 and the imaging device 6 are fixedly mounted on the support base 8 . In this embodiment, since the reflected light after passing through the cone internal reflector 2 is an annular light parallel to the axis of the deep hole, the imaging distance will not affect the spot image. Therefore, the screen 5 and the imaging device 6 can be fixedly arranged in the On the support base 8, there is no need to calibrate the imaging image based on the imaging distance.

Furthermore, in this embodiment, the connecting rod 3 is a telescopic rod, and the telescopic rod is provided with scales, and different scales correspond to different measurement apertures. As shown in FIG. 1 , in this embodiment, the distance between the ring laser emitter 4 and the conical inner reflector 2 can be adjusted through a telescopic rod, thereby adjusting the size of the imaging spot. When the length of the telescopic rod becomes smaller, the distance between the ring laser emitter 4 and the inner cone reflector 2 becomes smaller, thereby reducing the size of the ring spot in the imaged image.

Further, as shown in Figure 2, in this embodiment, it is assumed that the incident angle of the ring laser emitted by the ring laser emitter 4 on the inner wall of the deep hole of the workpiece 7 is α, and the angle between the conical inner reflector 2 is 2β, and its central axis is on a straight line with the axis of the deep hole, then the angles between the mirror surfaces on both sides and the axis of the deep hole are both β. In order to make the light reflected by the cone inner reflector 2 parallel to the axis of the deep hole direction of propagation, its angle should satisfy the following relationship:

α+(180-2β)=90°; (1)

Simplified to get:

2β-α=90°; (2)

The measurement principle of the present invention is introduced in detail below.

As shown in Figure 2, assume that δ is the radius difference between the deep hole radius of the workpiece 7 to be tested and the standard workpiece, and x is the radius difference of the annular light spot generated by the workpiece 7 to be tested and the standard workpiece. The incident points of the incident laser starting from point O where the ring laser transmitter 4 is located on the standard workpiece and the workpiece to be measured 7 are O' and O'' respectively, and the incident points on the cone inner reflector 2 are points B and A respectively. point, the intersection point of the reflected light passing through B and the light O''A is C. Draw a normal line passing through point O'' and intersect with the surface of the workpiece 7 to be measured at point M. Draw a parallel line of incident light OO' passing through point B and intersect light ray O'' A at point D; draw a reflection passing through point A along point C. The perpendicular line of the ray intersects at point A', then CA'= x , O '' M=δ.

∠A'CD=∠O''O'M=α, and O'O''=BD, then there is:

;(3)

Therefore there is:

;(4)

In △BAD, ∠BAD= β , then there is:

; (5)

Right now:

;(6)

In △BCD, there are:

;(7)

Right now:

;(8)

According to the angle relationship, there are:

∠ABD=β-（90°-α）=β＋α-90°=3β-180°; (9)

∠DBC=90°-α=180°-2β; (10)

∠BCD=180°-2β; (11)

Substituting equations (6), (8), (9)~(11) into equation (4), we get:

;(12)

Therefore, by measuring the radius difference x of the annular light spot, the radius deviation δ of the workpiece 7 to be measured relative to the standard workpiece can be calculated according to equation (12). In addition, it can be seen from equation (12) that when β is greater than 60°, x>δ, that is, the annular light spot of this embodiment can play a role in amplifying the aperture deviation. When β=75°, the magnification is 1.732.

Specifically, the angle 2β of the conical inner reflector 2 satisfies the condition: 2β＞120°.

Furthermore, this embodiment also includes a calculation unit, which is used to calculate the spot image collected by the imaging device 6 to obtain the deep hole aperture.

Since x is equal to the difference between the spot radius S/2 at the corresponding circumferential position in the spot image of the workpiece to be tested 7 and the average spot radius S ₀ /2 in the spot image corresponding to the standard workpiece, that is, x = (SS ₀ ) /2, then according to equation (12), the calculation formula of the deep hole diameter of the workpiece 7 to be measured is:

; (13)

in, Indicates the aperture size of the workpiece 7 to be tested,/> Represents half the angle of the inner cone mirror 2,/> Indicates the hole diameter of standard workpiece. The above analysis only analyzes a section passing through the central axis. If the section shown in Figure 2 is rotated axially around the central axis, the corresponding deep hole apertures at different circumferential positions of the light spot can be obtained. In addition, it should be noted that in this embodiment, the larger the spot diameter is, the smaller the corresponding workpiece aperture is.

Embodiment 2

Embodiment 2 of the present invention provides a deep hole detection method based on laser reflection, which is implemented based on a deep hole detection device described in Embodiment 1 and includes the following steps:

Step 1: Find the standard workpiece according to the nominal aperture of the workpiece 7 to be tested, put the deep hole detection device into the standard workpiece for measurement, obtain spot images multiple times, and calculate the average spot diameter size S in each spot image. ₁ .

Step 2: Place the deep hole detection device into the workpiece 7 to be tested, measure and obtain the spot image.

Step 3: Based on the spot image, calculate the aperture size of the workpiece 7 to be tested at multiple circumferential positions at the corresponding depth. The calculation formula is:

;(14)

Step 4: Change the measurement depth of the deep hole detection device in the workpiece 7 to be measured, repeat steps 2 and 3, and obtain the spot images of the workpiece 7 to be measured at different measurement depths and the corresponding apertures at multiple circumferential positions. size.

In addition, in this embodiment, the parameters such as roundness and cylindricity inside the deep hole can also be obtained through the spot images at various depths, and the clarity of the spot image boundary can also reflect the roughness of the inner wall of the deep hole. For example, after obtaining the corresponding aperture of the workpiece to be measured at various angles, by measuring the corresponding radius at different angles corresponding to a single spot image, the difference between the maximum and minimum radius values is calculated, and the radius tolerance value is obtained as the roundness of the workpiece to be measured 7 on the section. Then, by extracting the radii of multiple sections, the cylindricity of the workpiece to be measured 7 can be obtained.

Furthermore, the deep hole detection method based on laser reflection described in this embodiment also includes the step of calculating the roundness at each measurement depth and the step of calculating the cylindricity of the workpiece 7 to be measured.

Specifically, the step of calculating the roundness is: based on the aperture size of the workpiece 7 to be measured at each circumferential position measured at the corresponding depth, calculate the difference between the maximum value and the minimum value of the corresponding radius at each circumferential position, and obtain the radius tolerance. as the roundness at the corresponding measured depth;

Specifically, the steps for calculating cylindricity are: extract the aperture sizes at each circumferential position corresponding to multiple measurement depths, and calculate the corresponding radius tolerance as the cylindricity.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention. scope.

Claims (10)

1. A deep hole detection device based on laser reflection, characterized by including: a centering device (1), a cone internal reflector (2), a connecting rod (3), a ring laser transmitter (4), and a screen (5) and imaging device (6); one end of the conical internal reflector (2) and the connecting rod (3) is fixed on the central axis of the centering device (1), and the conical internal reflector (2) ) coincides with the central axis of the centering device (1); the ring laser emitter (4) is fixedly arranged on the outer periphery of the connecting rod (3), and its center is located on the axis of the centering device (1) , used to emit an annular beam to the inner wall of the deep hole of the workpiece to be measured (7). After the annular beam is reflected from the inner wall of the deep hole of the workpiece to be measured (7), it is incident on the conical inner reflector (2). The cone inner reflector (2) forms a parallel annular beam after reflection and is incident on the screen (5); the imaging device (6) is provided on the other side of the screen (5) for capturing the screen (5) The spot image on (7) in the deep hole. 2. A deep hole detection device based on laser reflection according to claim 1, characterized in that it also includes a support base (8), and the support base (8) is used to set the workpiece to be tested (7), so A support rod (9) is provided at one end of the support base (8), and a push rod (10) is provided on the support rod (9). The push rod (10) is used to push the centering device (1), The inner conical reflector (2) and the connecting rod (3) enter the deep hole of the workpiece (7) to be measured. 3. A deep hole detection device based on laser reflection according to claim 2, characterized in that the screen (5) and the imaging device (6) are fixedly arranged on the support base (8). 4. A deep hole detection device based on laser reflection according to claim 1, characterized in that the connecting rod (3) is a telescopic rod, and the telescopic rod is provided with scales, and different scales correspond to different measurement apertures. 5. A deep hole detection device based on laser reflection according to claim 1, characterized in that the ring laser emitted by the ring laser transmitter (4) is incident on the inner wall of the deep hole of the workpiece (7) to be tested. The angle α and the angle 2β of the cone internal reflector (2) satisfy the following relationship: 2β-α=90°. 6. A deep hole detection device based on laser reflection according to claim 1, characterized in that the included angle 2β of the conical internal reflector (2) satisfies the condition: 2β>120°. 7. A deep hole detection device based on laser reflection according to claim 1, characterized in that it also includes a calculation unit, the calculation unit is used to calculate the spot image collected by the imaging device (6) to obtain the deep hole detection device. Hole diameter, the calculation formula is: ; in, Indicates the aperture size of the workpiece to be measured (7), /> represents half of the angle of the conical inner reflector (2), S represents the spot diameter of the workpiece to be measured (7) at each circumferential position; _S0 represents the spot diameter corresponding to the standard workpiece, /> Indicates the hole size of a standard workpiece. 8. A deep hole detection method based on laser reflection, implemented based on a deep hole detection device based on laser reflection according to claim 1, characterized in that it includes the following steps: Step 1: Find the standard workpiece according to the nominal aperture of the workpiece to be tested (7), put the deep hole detection device into the standard workpiece for measurement, obtain spot images multiple times, and calculate the average spot diameter size in each spot image. value S ₁ ; Step 2: Place the deep hole detection device into the workpiece to be tested (7), measure and obtain the spot image; Step 3: Based on the spot image, calculate the aperture size of the workpiece to be tested (7) at multiple circumferential positions at the corresponding depth. The calculation formula is: ; in, Indicates the hole diameter of the workpiece (7) to be measured at each circumferential position,/> represents half of the angle of the inner cone reflector (2), and S represents the spot diameter of the workpiece to be measured (7) at each circumferential position;/> Indicates the hole size of the standard workpiece; Step 4: changing the measuring depth of the deep hole detection device in the workpiece (7) to be measured, repeating steps 2 and 3, and obtaining the light spot images of the workpiece (7) to be measured at different measuring depths and the corresponding aperture sizes. 9. A deep hole detection method based on laser reflection according to claim 8, characterized in that the aperture of the standard workpiece is equal to the nominal aperture of the workpiece to be tested (7). 10. A deep hole detection method based on laser reflection according to claim 8, characterized in that it also includes the step of calculating the roundness at each measurement depth and the step of calculating the cylindricity of the workpiece to be measured (7); The steps for calculating roundness are: based on the aperture size of the workpiece to be tested (7) measured at the corresponding depth at each circumferential position, calculate the difference between the maximum value and the minimum value of the corresponding radius at each circumferential position, and obtain the radius tolerance as Corresponds to the roundness at the measured depth; The steps for calculating cylindricity are: Extract the aperture size at each circumferential position corresponding to multiple measurement depths, and calculate the corresponding radius tolerance as the cylindricity.