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The new standard wind turbine bearing ring gear

Each wind turbine equipment with a yaw bearing ring and three pitch bearing ( part -megawatt wind turbines for the following non-adjustable blades , can not pitch bearing ) .

Wind turbine bearings can be divided into three categories, namely: yaw bearings, pitch bearings , transmission bearings ( main shaft and gearbox bearings ) . The connecting portion of the yaw bearing mounted on a tower and the cockpit , the pitch bearing mounted on the base and connected to the hub portion of each blade . Each wind turbine equipment with a yaw bearing ring and three pitch bearing ( part -megawatt wind turbines for the following non-adjustable blades , can not pitch bearing ) .

First, the code method

Wind turbine yaw , pitch bearing code method uses JB/T10471-2004 the turntable bearing the code method, but in the wind turbine yaw , pitch bearing appeared double four point contact ball bearing turntable , and this structure is not specified in the letter bearing JB/T10471-2004 , and therefore, an increase in the standard double-row four point contact ball slewing bearing code . Since the single-row four point contact ball slewing bearing structure type code indicated by 01 , and structure type code 02 represents the double ball slewing bearing structure , and therefore the provisions of 03 means that the tooth -row four -point contact ball slewing bearing structure circle.

Second, the technical requirements

1 , Material

This standard specifies the yaw , pitch bearing ring material selection 42CrMo, heat treatment with the overall quenching, the quenched hardness of 229HB-269HB, raceway part is surface hardening, quenching hardness 55HRC-62HRC. As the wind turbine yaw , pitch bearing force situation is complex, and bearing to withstand shock and vibration is relatively large, and therefore , requires both bearings to withstand the impact , but also bear a greater load. Wind turbines host life requirements of 20 years, the cost of bearing a larger installation , thus requiring yaw , pitch bearing ring gear life have reached 20 years. Such matrix hardness of the bearing rings 229HB-269HB, able to withstand impact without plastic deformation , while the surface portion of the quenching roller slopes reach hardness 55HRC-62HRC, contact fatigue life can be increased to ensure long bearing life requirements .

2 , low-temperature impact energy

The standard yaw , pitch wheel bearing rings low impact energy requirements : -20 ℃ Akv not less than 27J, Akv cold state value determined in consultation with the user . Wind turbines may operate in very cold regions, it is about the ambient temperature as low as -40 , bearing operating temperature of about -20 ~ C , the ring gear bearings under low temperature conditions must be able to withstand high impact load, and therefore , requires bearings ferrule material after quenching low-temperature impact energy test must be done , in part to take on the bearing rings made of sample or rings with the same performance and the same under the heat treatment conditions sample at -20 ~ C environment do impact energy test .

3 , the bearing inner ring

Since the drive wind turbine bearing accuracy is not high, but the relatively large diameter ring gear , gear modulus is relatively large, and therefore , generally require precision grade gear at GB/T10095.2---2001 of 9 or 10 . However, due to the operating state between the pinion and the ring gear bearing the impact , and therefore , the tooth surface of the bearing ring to be hardened , the pinion tooth surface hardness is generally 60HRC, hardened tooth surface considering the life of such design , a large gear hardness is defined as not less than 45HRC.

4 , clearance

Yaw , pitch bearings have special requirements in terms of clearance . With respect to the yaw bearing , pitch bearing impact load is relatively large, the wind on the blade vibration is large , so they requested that the pitch bearing clearance should be zero or slightly negative clearance clearance values , so in case of shock bearings can be reduced under fretting wear .

Yaw bearing clearance requirements for the small value , ie 0-501 ~ m. Further , the rotation of the wind turbine pitch and yaw bearings driven by the drive motor , the bearing clearance or negative clearance state should ensure that a small drive motor can be driven , and therefore , after assembly, the bearing starting frictional load measurement requires torque , specific torque values depending on the host drive systems are not the same .

5 , anti-corrosion treatment

Wind turbine equipment in the field work, and yaw , pitch bearing part is bare, exposed , will be air pollution , high humidity will corrode bearing matrix , therefore , exposed bare yaw and pitch bearings site requirements for surface corrosion treatment , commonly used galvanized. If necessary, a protective outer zinc layer painting process .