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Bearing 180204 |
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| News details |
The Problem of Attention in Sliding Bearing
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| Time：2016.11.10 News Sources：Shandong Xinkaite bearing Co.,Ltd. Views：
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Sliding bearing is the surface contact, so the contact surface to maintain a certain oil film, so the design should pay attention to the following questions:
1, to make the oil film can smoothly into the friction surface.
2, oil from the bearing surface into the bearing area.
3, do not make the whole ring oil groove in the middle of the bearing.
4, such as oil tiles, seams at the oil groove.
5, to make oil ring oil fully reliable.
6, filling holes do not be blocked.
7, do not form the oil does not flow area.
8, to prevent the sharp edges and edges cut off the oil film.
Sliding bearings can also be used to lubricate the grease, grease in the choice should consider the following points:
(1) bearing load, low speed, the cone should be selected into the small grease, and vice versa to choose a large cone penetration. High-speed bearings selected cone penetration of small, good mechanical stability of the grease. Of particular note is the viscosity of the grease base oil to be lower.
(2) Select the grease dropping point is generally higher than the working temperature of 20-30 ℃, continuous operation at high temperatures in the case, be careful not to exceed the allowable temperature range of grease.
(3) sliding bearings in the wet or wet environment work, should choose a good water-resistant calcium-based, aluminum or lithium-based grease.
(4) choose a better adhesion of the grease.
2, the choice of plain bearings with grease:
Load <1MPa, journal peripheral speed 1m / s or less, the maximum operating temperature of 75 ℃, the choice of calcium-based grease 3;
Load 1-6.5MPa, journal peripheral speed of 0.5-5m / s, the maximum working temperature of 55 ℃, the choice of calcium-based grease 2;
Load> 6.5MPa, journal peripheral speed of 0.5m / s or less, the maximum operating temperature of 75 ℃, the choice of calcium-based grease 3;
Load <6.5MPa, journal peripheral speed of 0.5-5m / s, the maximum operating temperature of 120 ℃, the choice of No. 2 lithium grease;
Load> 6.5MPa, shaft peripheral speed of 0.5m / s or less, the maximum operating temperature of 110 ℃, the choice of No. 2 calcium - sodium base grease;
Load 1-6.5MPa, journal peripheral speed of 1m / s or less, the maximum operating temperature of 50-100 ℃, the choice of No. 2 lithium grease;
Load> 5MPa bearing circumferential speed 0.5m / s, the maximum working temperature of 60 ℃, the choice of No. 2 calendar fat;
In humid conditions, the temperature at 75-120 ℃ under the conditions should be considered with calcium - sodium base grease. In a humid environment, the operating temperature below 75 ℃, no calcium-based grease 3, aluminum grease can also be used. Operating temperature 110-120 ℃, the available lithium-based grease or barium base grease. Concentrated lubrication, consistency should be smaller.
3, the sliding bearing grease lubrication cycle:
Accidental work, not important parts: shaft speed <200r / min, lubrication cycle 5 days time; shaft speed> 200r / min, lubrication cycle 3 days.
Intermittent work: shaft speed <200r / min, lubrication cycle once a day; shaft speed> 200r / min, lubrication cycle once a day.
Continuous working, the working temperature is less than 40 ℃: shaft speed <200r / min, lubrication cycle once a day; shaft speed> 200r / min, lubrication cycle once per shift.
Continuous working, working temperature 40-100 ℃: shaft speed <200r / min, lubrication cycle once per shift; shaft speed> 200r / min, lubrication cycle of two classes.
It is necessary to make the journal and sliding bearing even fine contact, but also have a certain gap.
Refers to the journal and the sliding bearing contact surface of the center of the angle. Contact angle can not be too big nor too small. Contact angle is too small will increase the sliding bearing pressure, severe sliding bearings will have a greater deformation, accelerated wear and shorten the service life; contact angle is too large, will affect the formation of oil film, not a good liquid lubrication.
Experimental study shows that the contact angle of the sliding bearing is limited to 120 °. When the sliding bearing wear to this contact angle, the liquid lubrication is destroyed. So do not affect the bearing pressure conditions under the premise of the contact angle the smaller the better. From the theoretical analysis of friction distance, when the contact angle of 60 °, the friction torque is the smallest, it is recommended that the speed is higher than 500r / min sliding bearings, contact angle of 60 °, speed less than 500r / min sliding bearings, The contact angle may be 90 ° or 60 °.
The actual contact between the journal and the sliding bearing surface can be expressed as the actual number of contact points per unit area. More contact points, the more fine, the more uniform, said the better sliding bearing scratch research, on the contrary, said sliding bearing scratch research is not good. Generally speaking, the closer the more contact points more difficult to scratch the more research. Production should be based on the performance of sliding bearings and working conditions to determine the contact points, the following information is available for reference:
Sliding bearing speed (r / min) Contact point
(Number of contacts per 25 x 25 mm area)
100 or less 3 to 5
100 to 500 10 to 15
500 to 1000 15 to 20
1000 to 2000 20 to 25
2000 or more 25 or more
Ⅰ and Ⅱ level of precision machinery can be used on the table data, Ⅲ precision machinery can be halved according to the above data.
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