CN114894125B - Quantitative detection method for radial ball bearing raceway line - Google Patents

Abstract

The invention discloses a quantitative detection method for a radial ball bearing raceway line, which comprises the following steps: s1, cutting, embedding, polishing, hot pickling and cleaning a bearing, and then photographing; 2. the photo is imported into drawing software, the position of the center of the curvature circle of the roller path in the photo is determined, the curvature circle which coincides with the roller path is made, and after the position of the contact point is determined, the measuring range and 5 measuring positions are determined within the contact angle range; s3, measuring the included angles between the parallel lines of the streamline direction and the radius at 5 measuring positions, and subtracting 90 degrees from the included angles to obtain the accurate numerical value of the streamline distribution of the rollaway nest. The method can be used for compensating the blank of quantitative evaluation of the streamline distribution of the bearing raceway, is simple to operate and high in accuracy, and can be operated and detected by non-professional technicians.

Description

Quantitative detection method of raceway line of radial ball bearings

Technical field

The present invention relates to bearing detection, specifically a quantitative detection method for raceway lines of radial ball bearings.

Background technique

During the smelting process of bearing steel, the material purity is mainly controlled, but there are still deoxidation products such as Al2O3, sulfide, titanium nitride and low melting point compounds remaining in the steel. During the continuous casting process, the material uniformity is mainly controlled, but there are still Segregation problems exist with the formation of banded carbides. In the subsequent rolling process of bearing steel, as the rolling ratio becomes larger, the above residues and band carbides will be distributed along the rolling direction to form streamlines.

Streamlines will affect the mechanical properties of structural parts, and the distribution of streamlines along the shape of the part can improve the strength of the part. For bearings, streamlines mainly affect the fatigue performance of the bearing. For example, if the two poles and annulus of the steel ball are areas cut off by streamlines, fatigue spalling will often occur here. During the operation of the bearing, the raceway position is subjected to cyclic contact stress, and fatigue spalling may also occur due to the distribution of streamlines. There are currently many processes that affect the streamline distribution of bearing products, such as steel pipe straight turning, sleeve forging, single forging, cold extrusion, hot rolling, cold rolling, and even the upsetting height and mold design during the forging process. Therefore, the flow of bearing products The distribution of lines varies widely. The angle between the tangent lines at the contact point between the streamlines and the raceway represents the degree of parallelism between the streamlines and the raceway. The smaller the angle, the more parallel the streamlines and the raceway are, and the better the fatigue life of the bearing. The streamlines at the raceway are The greater the angle between the tangent lines of the raceway contact point, the worse the fatigue performance.

Among radial ball bearings, deep groove ball bearings are currently the most widely used bearings. However, there is currently no simple and universal method to quantitatively describe the streamline distribution.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a quantitative detection method for radial ball bearing raceway lines, which can be used to fill the gap in the quantitative evaluation of bearing raceway streamline distribution, and has simple operation and high accuracy. High, even non-professional technicians can operate and perform inspections.

In order to achieve the above objects, the present invention provides the following technical solutions:

A method for quantitatively detecting raceway lines of radial ball bearings, including the following steps:

S1. Cut, inlay, polish, hot pickle, and clean the bearings before taking pictures;

S2. Import the photos into the drawing software, determine the center position of the raceway curvature circle in the picture, and draw a curvature circle that coincides with the raceway. After determining the contact point position, determine the measurement range and 5 measurement positions within the contact angle range;

S3. Measure the angle between the parallel line in the streamline direction and the radius at 5 measurement positions. After subtracting 90 degrees from the angle, the accurate value of the raceway streamline distribution is obtained.

Based on this process, it is easy to operate and can be operated by non-professional technicians. It has wider applicability, frees up professional and technical personnel in the quality inspection process, and improves corporate R&D efficiency. At the same time, it can also fill the gap in the quantitative evaluation of bearing raceway streamline distribution. It has high accuracy and can maintain high accuracy even when operated by non-professional technicians.

As a further improvement of the present invention, CAD software is used as the drawing software. CAD software is easy to operate and has wide applicability. Its built-in point capture and angle capture can quickly perform operation and positioning. However, the detection efficiency is higher. For non-professional technicians, it is quick to get started and the operation error rate is low.

As a further improvement of the present invention, the optimal center of the curvature circle and the position of the curvature circle are determined through drawing software. Using the multi-point circle or multi-point arc drawing function of CAD software, the software can quickly and automatically calculate an arc that fits the raceway in the photo.

As a further improvement of the present invention, the contact angle is determined according to the type of bearing, and the range of the contact angle is 0-45°. Different contact angles are determined according to the type of bearing. The contact angle determines the measurement range. Different contact angles are selected according to the different measurement ranges required for different bearings.

As a further improvement of the present invention, the measurement range in step S2 is determined according to the following steps: determine the center position O of the curvature of the raceway, and the contact point position A between the steel ball and the raceway, connect OA to make an arc that coincides with the raceway, and use OA is the boundary ±α range, α is the contact angle 0~45°, that is, ∠AOE=α, ∠AOD=α; arc DE is the measurement range. The operation steps are simple, can be quickly performed through CAD software, and can also be easily implemented by non-professional technicians.

As a further improvement of the present invention, the positions of the five measurement points in step S2 are determined according to the following steps: bisect ∠AOE to obtain the intersection point C on the arc, bisect the angle AOD to obtain the intersection point B, points E, C, and A on the arc, B and D are the 5 measurement positions in the measurement range. The five measurement positions obtained through this solution are more uniform, which can make the detection effect more accurate.

Description of the drawings

Figure 1 is a schematic diagram of the point selection results of the present invention;

Figure 2 is a schematic diagram of the example detection results of the present invention (without improvement);

Figure 3 is a schematic diagram of the detection results (improved) of an example of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the embodiments shown in the accompanying drawings.

Refer to Figure 1-3,

A method for quantitatively detecting raceway lines of radial ball bearings, including the following steps:

(1) The bearing is cut about 5mm wide along the cross section, and is mounted with a hot mounting material with a particle size less than 0.2mm. Use 100 mesh, 400 mesh, 1200 mesh, and 2000 mesh alumina waterproof sandpaper to grind the samples respectively, and use diamond. Spray polishing agent for polishing, use hydrochloric acid aqueous solution (1:1), perform hot pickling at a temperature of 70-80°C, and keep it warm for 15-30 minutes. First rinse with tap water, then clean with alcohol. After drying, the streamlines are clearly visible, take photos and save them.

(2) Import the photos into professional drawing software CAD, calculate and convert the relevant dimensions of the bearing drawing to determine the center position O of the curvature of the raceway, and the position A of the contact point between the steel ball and the raceway, connect OA to create an arc that coincides with the raceway , with OA as the boundary ±α range, α is the contact angle of about 0~45°, that is, ∠AOE=α, ∠AOD=α. The arc DE is the measurement range.

(3) Bisect ∠AOE to get point C, bisect angle AOD to get point B. Points E, C, A, B, and D are the five measurement positions in the measurement range. Refer to Figure 1.

(4) Draw 5 short lines along the streamline direction at 5 measurement positions, and measure the angles between the 5 short lines and the radius respectively, then ∠E-90°, ∠C-90°, ∠A-90°, ∠ B-90°, ∠D-90° is the angle between the streamline and the tangent line of the raceway contact point.

The calculated angle can reflect whether there is a risk of fatigue spalling in each area.

The following examples illustrate:

Referring to Figure 2,

(1) The inner ring of a 6201 model deep groove ball bearing is cut and mounted, hot pickled, cleaned with water and alcohol, and then photographed.

(2) Import CAD drawing, determine the circle center O, the measurement range arc DE, and the measurement position points E, C, A, B, D

(3) Draw a line along the streamline direction at the measurement position points E, C, A, B, and D, and measure the angle between it and the radius.

(4) The streamline distribution at the bearing raceway is obtained:

∠E-90°＝128°-90°＝38°

∠C-90°＝119°-90°＝29°

∠A-90°＝98°-90°＝8°

∠B-90°＝97°-90°＝7°

∠D-90°＝105°-90°＝15°

The angle between the streamline and the tangent line of the raceway contact point in the CE area is relatively large, so there is a higher risk of fatigue spalling compared to other measurement range areas.

Referring to Figure 3,

(1) The inner ring of an improved 6201 model deep groove ball bearing was cut and mounted, then hot pickled, cleaned with water and alcohol, and then photographed.

(2) Import the CAD drawing, determine the circle center O’, the measurement range arc D’E’, and the measurement position points E’, C’, A’, B’, D’

(3) At the measurement position points E’, C’, A’, B’, D’, draw a line along the streamline direction and measure the angle between it and the radius

(4) The streamline distribution at the bearing raceway is obtained:

∠E’-90°＝105°-90°＝15°

∠C’-90°＝96°-90°＝6°

∠A’-90°＝99°-90°＝9°

∠B’-90°＝96°-90°＝6°

∠D’-90°＝109°-90°＝19°

After the improvement, the angle between the streamlines at the raceway and the contact point of the raceway is smaller, which has less impact on the fatigue life of the bearing.

The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. All technical solutions that fall under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications may be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (4)

1. The quantitative detection method for the radial ball bearing raceway line is characterized by comprising the following steps of:

s1, cutting, embedding, polishing, hot pickling and cleaning a bearing, and then photographing;

s2, importing the photo into drawing software, determining the position of the circle center of curvature of the roller path in the photo, making a curvature circle coincident with the roller path, determining the position of a contact point, and determining a measuring range and 5 measuring positions within the contact angle range;

s3, measuring included angles between parallel lines of the streamline direction and the radius at 5 measuring positions, and subtracting 90 degrees from the included angles to obtain accurate values of streamline distribution of the rollaway nest;

the measurement range in step S2 is determined according to the following steps:

determining the curvature circle center position O of the raceway and the contact point position A of the steel ball and the raceway, connecting OA to be an arc coincident with the raceway, and taking OA as a boundary + -alpha range, wherein alpha is a contact angle of 0-45 degrees, namely +.AOE=alpha and +.AOD=alpha; the arc DE is the measuring range;

the 5 measurement points in step S2 are determined according to the following steps:

bisecting the angle AOE to obtain an intersection point C on the circular arc, bisecting the angle AOD to obtain an intersection point B on the circular arc, and obtaining 5 measuring positions in a measuring range by points E, C, A, B and D.

2. The method of claim 1, wherein the mapping software is CAD software.

3. The method of claim 1, wherein the optimal center of curvature and location of the circle of curvature are determined by mapping software.

4. A method according to claim 3, characterized in that the contact angle is in the range of 0-45 ° depending on the kind of bearing.