Failure failure of thrust ball bearing for pump

Time：2020.10.12  Source：Roller Bearings Suppliers

Thrust ball bearing wear failure is one of the common failures. For example, during the use of a certain type of hydraulic pump, the thrust ball bearing in the pump has a serious wear failure failure. The specific thrust ball bearing wear failure form is described below by ZZ Bearing (Shanghai) Co., Ltd made a detailed introduction.

1. Abrasion failure fault appearance of thrust ball bearing for pump

The thrust ball bearing is composed of shaft washer, seat ring, cage and 11 steel balls. Among them, the raceway of the shaft ring is severely worn, and rough pits can be seen locally, and the edge of the raceway is protruding and "climbing" phenomenon due to wear and extrusion. The overall damage of the seat ring is lighter, and the surface of the raceway is golden yellow and smooth , Small pits and rolling grooves can be seen locally. All 11 steel balls showed high temperature discoloration and turned dark black, 3 steel balls were broken (pointed by the red arrow), 8 steel balls were relatively intact and all showed different degrees of wear or extrusion damage, and some steel balls stuck in pockets The inside of the cage cannot be rotated. The pockets of the cage are worn and the edges are raised

2. Feature of steel ball fracture

The fracture characteristics of the three broken steel balls are basically the same. The macroscopic surface of the fracture is blue-black and the surface is severely worn; the microscopic features are mainly dimples, and the mixed features of intergranular + dimples are locally visible, showing the characteristics of overload fracture.

3. Analysis of wear failure results of thrust ball bearings

There are no signs of fatigue peeling on the shaft ring, seat ring and steel ball of the faulty bearing, indicating that the main manifestation of the initial bearing failure should be wear. After consulting the previous data, it is found that the previous fault appearance of the bearing is basically similar. The bearing shaft ring is seriously worn. Most steel balls The surface has a large area of ? wear and blackening, and it is stuck in the cage pocket and cannot rotate. ZZ 23030 CC/W33 bearings online , pls click here :

This phenomenon should be due to the fact that a large amount of metal scraps produced by abrasion during the failure of the bearing are squeezed and clamped in the cage pocket, hindering the rotation of the steel ball until it is stuck, and finally the bearing shaft ring and the steel ball cage assembly Severe sliding wear occurs.

When the thrust bearing is assembled and used in the pump, the outer diameter of the seat ring is not positioned. The positioning is mainly achieved by the pre-tightening force generated by the outer end surface pressed by 6 springs. The bearing has to bear the alternating axial eccentric load during the working process. It is inevitable that there will be a fixed radial swing, resulting in a radial offset. As the radial movement of the seat ring increases, the contact angle will decrease significantly. "The occurrence of the state can ultimately be judged from the abnormal contact marks of the shaft ring or raceway channel.

If the shaft ring is incorrectly positioned when the bearing is installed, an initial eccentricity is formed, and under the action of the alternating axial eccentric load during the working process, the bearing ring will have a certain radial swing. The superposition of the two will cause the seat ring The amount of radial movement increases significantly, which will inevitably cause the bearing to run unstable and deviate from the normal working track, leading to early wear of the working surface of the bearing parts. ZZ 23032 CC/W33 bearings online , pls click here :

The bearing shaft ring groove edge of the faulty bearing was seriously worn out. Due to the effects of abrasion and compression, the edge part of the groove was raised and appeared a typical "climbing" phenomenon, and there were no signs of fatigue peeling on the shaft ring, seat ring and steel ball. , Indicating that the main manifestation of the initial bearing failure should be wear, and the wear should be related to the unstable operation of the bearing during the working process, and the deviation of the contact position between the steel ball and the raceway from the normal working track.