Overview (More steel balls can be found in Guangdong Steel Balls)
Rolling bearings should have basic properties such as long life, low vibration, low noise, small rotational torque and high reliability. To achieve the above performance, we must ensure that the machining accuracy of the bearing parts, the processing quality of steel balls, ferrules and cages have an impact on the bearing vibration, in which the processing quality of the steel ball has the most obvious impact on the bearing vibration, and the outstanding problem is steel. The vibration value of the ball is discrete and the surface defects are serious. Random quality problems such as scratching, scratches, and burns must be avoided. The basic problem facing the bearing industry is to reduce the vibration and noise of the bearings. This requires improving the geometric accuracy of the steel balls and ferrules and reducing the roughness of the working surface.
This article focuses on the impact of various indicators of the ball on bearing vibration and noise.
The impact of various technical indicators of the steel ball on bearing performance:
The quality of the ball directly affects the bearing performance.
Its various technical indicators mainly include:
Steel ball shape error, steel ball surface roughness, ball surface defects, etc.
2.1
The influence of the shape error of the ball on the performance of the bearing The shape error of the ball is one of the important factors affecting the vibration and noise of the bearing.
During the processing of the steel ball, the steel ball forms a contact pair with the surface of the groove, receives squeezing and friction, consumes excess metal on the surface of the ball blank, and gradually wears the ball into a ball. In order to reduce the error of the ball shape, various technical measures have been taken in the process. The greater the shape error of the ball, the greater the vibration value of the bearing, so the shape error of the ball must be reduced. When the bearing rotates, due to the error in the shape of the steel ball, the center position of the steel ball is forcibly changed to cause bearing vibration and noise, and the shape error of the steel ball causes the bearing to generate low-frequency vibration.
2.2
The influence of the surface roughness of the ball on the bearing
The surface roughness of a steel ball usually refers to the surface microscopic irregularities other than the ball surface, spherical error, and waviness. The surface roughness of the ball has a great influence on the vibration of the bearing at high and medium frequencies, causing the bearing to generate noise. The surface roughness of the steel ball affects the vibration of the bearing much larger than the surface roughness value of the bearing ring. The vibration value of the bearing is higher. Therefore, the steel ball surface roughness must be reduced.
2.3
The Effect of Ball Surface Defect on Bearing Performance
Cracks on the surface of the steel ball due to unloading, rust corrosion, or raw materials.
Scratches, rust, and dents are collectively referred to as surface defects. Steel balls are not allowed to have surface defects. Because the surface defects of the steel ball will excite the impulse-type vibration of the bearing, vibration and noise will be generated when the bearing rotates. The pulse cycle is inversely proportional to the bearing rotation speed, and the amplitude is related to the size of the defect. The greater the surface defects developed by testing the ball, the higher the bearing vibration value.
2.4
The effect of ball hardness on bearing performance The hardness of the ball directly affects the fatigue life and dynamic performance of the bearing. The test results show that when the hardness of the steel ball is about 62HRC, the contact fatigue life is the highest; when the hardness changes in the range of 57-65HRC, the higher the hardness, the better the corrosion resistance; when the hardness value is lower than 61HRC, the wear resistance The effect is not obvious. The difference in the hardness of the ball in the same set of bearings is as small as possible. The hardness of the ball also has a significant effect on the vibration of the bearing. When the steel balls with hardness of 63HRC and 66HRC are assembled with the same ferrule, the vibration value of the former is 3dB larger than that of the latter.
For bearings with vibration values,
The hardness of the steel ball is in the range of 65-67 HRC, and the difference between the hardness of the steel ball in the same set is not more than 0.5 HRC.
2.5
The Effect of Steel Ball Surface Grinding Burn on Bearing Performance
Grinding on the surface of a steel ball is a process of grinding after quenching and tempering. Due to an abnormal cause, the surface of the ball is suddenly hit, touched, rubbed, or ground, causing the temperature of the metal in the area to rise to quenching. After the tempering temperature is reached, cooling is immediately received, ie grinding burns are formed in the area.
Grinding burns can only be revealed by cold pickling according to a certain method. Because grinding burns can only be shown by cold pickling in a certain way. Since the metallographic structure and hardness of the grinding burns are different from those in the normal area, it becomes a hidden danger of early spalling and the contact fatigue strength is significantly reduced. Tests have shown that steel balls with burns have an average life expectancy of 16% lower than that of burned steel balls.
3 Summary
The steel balls in the ball bearings play a role in bearing and transmitting loads, and are the key components in the bearings. Improve the technical indicators of the steel ball can reduce the vibration and noise of the bearing. Practical use of silent bearings in everyday life can reduce the noise of household batteries, protect us from noise and improve our quality of life.
Rolling bearings should have basic properties such as long life, low vibration, low noise, small rotational torque and high reliability. To achieve the above performance, we must ensure that the machining accuracy of the bearing parts, the processing quality of steel balls, ferrules and cages have an impact on the bearing vibration, in which the processing quality of the steel ball has the most obvious impact on the bearing vibration, and the outstanding problem is steel. The vibration value of the ball is discrete and the surface defects are serious. Random quality problems such as scratching, scratches, and burns must be avoided. The basic problem facing the bearing industry is to reduce the vibration and noise of the bearings. This requires improving the geometric accuracy of the steel balls and ferrules and reducing the roughness of the working surface.
This article focuses on the impact of various indicators of the ball on bearing vibration and noise.
The impact of various technical indicators of the steel ball on bearing performance:
The quality of the ball directly affects the bearing performance.
Its various technical indicators mainly include:
Steel ball shape error, steel ball surface roughness, ball surface defects, etc.
2.1
The influence of the shape error of the ball on the performance of the bearing The shape error of the ball is one of the important factors affecting the vibration and noise of the bearing.
During the processing of the steel ball, the steel ball forms a contact pair with the surface of the groove, receives squeezing and friction, consumes excess metal on the surface of the ball blank, and gradually wears the ball into a ball. In order to reduce the error of the ball shape, various technical measures have been taken in the process. The greater the shape error of the ball, the greater the vibration value of the bearing, so the shape error of the ball must be reduced. When the bearing rotates, due to the error in the shape of the steel ball, the center position of the steel ball is forcibly changed to cause bearing vibration and noise, and the shape error of the steel ball causes the bearing to generate low-frequency vibration.
2.2
The influence of the surface roughness of the ball on the bearing
The surface roughness of a steel ball usually refers to the surface microscopic irregularities other than the ball surface, spherical error, and waviness. The surface roughness of the ball has a great influence on the vibration of the bearing at high and medium frequencies, causing the bearing to generate noise. The surface roughness of the steel ball affects the vibration of the bearing much larger than the surface roughness value of the bearing ring. The vibration value of the bearing is higher. Therefore, the steel ball surface roughness must be reduced.
2.3
The Effect of Ball Surface Defect on Bearing Performance
Cracks on the surface of the steel ball due to unloading, rust corrosion, or raw materials.
Scratches, rust, and dents are collectively referred to as surface defects. Steel balls are not allowed to have surface defects. Because the surface defects of the steel ball will excite the impulse-type vibration of the bearing, vibration and noise will be generated when the bearing rotates. The pulse cycle is inversely proportional to the bearing rotation speed, and the amplitude is related to the size of the defect. The greater the surface defects developed by testing the ball, the higher the bearing vibration value.
2.4
The effect of ball hardness on bearing performance The hardness of the ball directly affects the fatigue life and dynamic performance of the bearing. The test results show that when the hardness of the steel ball is about 62HRC, the contact fatigue life is the highest; when the hardness changes in the range of 57-65HRC, the higher the hardness, the better the corrosion resistance; when the hardness value is lower than 61HRC, the wear resistance The effect is not obvious. The difference in the hardness of the ball in the same set of bearings is as small as possible. The hardness of the ball also has a significant effect on the vibration of the bearing. When the steel balls with hardness of 63HRC and 66HRC are assembled with the same ferrule, the vibration value of the former is 3dB larger than that of the latter.
For bearings with vibration values,
The hardness of the steel ball is in the range of 65-67 HRC, and the difference between the hardness of the steel ball in the same set is not more than 0.5 HRC.
2.5
The Effect of Steel Ball Surface Grinding Burn on Bearing Performance
Grinding on the surface of a steel ball is a process of grinding after quenching and tempering. Due to an abnormal cause, the surface of the ball is suddenly hit, touched, rubbed, or ground, causing the temperature of the metal in the area to rise to quenching. After the tempering temperature is reached, cooling is immediately received, ie grinding burns are formed in the area.
Grinding burns can only be revealed by cold pickling according to a certain method. Because grinding burns can only be shown by cold pickling in a certain way. Since the metallographic structure and hardness of the grinding burns are different from those in the normal area, it becomes a hidden danger of early spalling and the contact fatigue strength is significantly reduced. Tests have shown that steel balls with burns have an average life expectancy of 16% lower than that of burned steel balls.
3 Summary
The steel balls in the ball bearings play a role in bearing and transmitting loads, and are the key components in the bearings. Improve the technical indicators of the steel ball can reduce the vibration and noise of the bearing. Practical use of silent bearings in everyday life can reduce the noise of household batteries, protect us from noise and improve our quality of life.
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