There are many reasons for causing low-frequency vibration, and the magnitude and damage of vibration caused by each cause are also different. There are various repair methods. Therefore, it is necessary to first identify the main cause of vibration and solve the main contradiction. Now combined with the transmission structure of the ball mill pinion bearing housing, the common causes and treatment methods of vibration are analyzed.
1 Vibration of the pinion housing caused by imbalance
(1) The gear (small, large) hole position is defective.
(2) The inner diameter of the gear shaft is eccentric.
(3) The gear material is defective and has trachoma.
(4) Partial wear of the gear.
(5) The steel ball in the body of the large ring gear is bonded to the material, resulting in an imbalance.
Although the above imbalance is high in the ratio of the rotating equipment, the imbalance in the actual work has little effect on the vibration of the ball bearing housing.
2 Couplings are equipped with vibrations caused by different axes
There are three types of couplings for different shafts: the two-axis centerline has a radial offset; the two-axis and centerline skew; the two-axis centerline simultaneously offsets and measures the axial and radial directions of the coupling. gap. Excessive deviations will cause additional loads on the coupling, drive shaft and bearings, resulting in heat, vibration, wear and even fatigue and breakage.
Adjustment measures:
First measure the axial and radial clearance of the coupling. Second: Analyze which case the coupling is misaligned. If there is a simultaneous occurrence of skew and offset. First calculate the skew adjustment and then calculate the offset adjustment because the skew adjustment affects the offset. Then adjust the coupling according to the calculated value.
3 Vibration caused by unreasonable assembly of the gear shaft
1. The pinion vibration caused by the flank clearance and the top clearance of the large and small gears. First check if the flank clearance and top clearance of the large and small gears meet the requirements. The side clearance and top clearance of the gear drive should be appropriate. A certain side and top clearance can compensate for the manufacturing and assembly deviation of the gear, compensate for thermal expansion and form an oil film to prevent jamming. However, too large a gap can cause an impact. If the gap is too large or too small, it will cause additional load, increase the wear of the gear transmission, and even bring accidents. The common method of measuring the gap is to use the lead method.
Second, the pinion vibration caused by the unreasonable contact of the pinion tooth surface. The contact area of ​​the gear is represented by the percentage of the total length of the tooth and the total height of the tooth in the contact portion between the tooth length and the tooth height, and the normal contact surface should be evenly distributed on the working surface of the tooth. If the contact surface is small or the contact position is incorrect, the load will be concentrated, causing local wear and vibration. The following reasons are analyzed for the following tooth surface contact conditions and adjustment measures are proposed.
(1) Co-directional contact.
Cause: The two gear axes are not parallel.
Adjustment method: scrape the bearing bush or adjust the bearing seat within the allowable range.
(2) Anisotropic partial contact.
Cause: The two gear axes are skewed or the tooth direction is deviated.
Adjustment method: scrape the bearing bush or adjust the bearing seat within the allowable range, or trim the gear teeth with tooth misalignment.
(3) Single-sided partial contact.
Cause: The two gear axes are not parallel and skewed at the same time.
Adjustment method: scrape the bearing bush or adjust the bearing seat within the allowable range.
(4) The contact area is gradually moved from one side to the Other, and the period is the number of teeth of the large gear or the small gear.
Cause: The reference end face of the large gear or pinion is not perpendicular to the center line of rotation.
Adjustment method: The deviation is within the allowable range, and the tooth surface of the deviation gear is trimmed.
(5) Contact with the top of the tooth.
Cause: The center distance of the gear axis is large or the gear is machined with a deviation of the original tooth shape or the diameter of the top circle of the gear blank is too large.
Adjustment method: within the allowable range, adjust the axis and increase the center distance, otherwise trim the tooth surface.
(6) The contact area is gradually moved from the tooth tip to the root of the tooth, and the period is the number of teeth of the large gear or the small gear.
Cause: The ring gear is bouncing radially.
Adjustment method: Trim the deviation of the teeth within the allowable range.
4 Vibration caused by loose bolts
Looseness is caused by the tight fastening of the bolts.
Inspection method: Check the fastening bolts of all transmission parts one by one to see if there is any looseness.
Adjustment method: Check the connecting bolts of all transmission parts and tighten them. If necessary, take bolts to prevent loosening.
5 Vibration of the pinion housing caused by vibration of the bearing itself
The wear of the bearing rolling elements causes the bearings to heat up and vibrate.
Solution: Check if the axial and radial clearance of the bearing exceeds the standard and the rolling element is seriously worn. Otherwise, the bearing should be replaced. After replacement, the bearing clearance must meet the assembly requirements.
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