Manufacturing Process Of Wheel Hub Bearings

There are more than 70 complete production steps for a wheel hub bearing. The main processes and processes are introduced here to help us have a general understanding of the bearing production process. If you want to get more information, welcome to visit our factory.

The main production steps can be divided into the following six steps:

1. Forging→Normalizing

Forgings:

The raw materials are GCR15 and 65MN. The materials are cut to length according to the parts that need to be processed, then heated, and then forged according to the part mold.

Material:
A Inner ring: GCR15
B Outer ring: 65MN
C Flange: 65MN

Normalizing:

Through the heat treatment normalizing process, the forgings are normalized for 4-5 hours to eliminate material stress and stabilize the internal structure of the material.

1)Heat to more than 600 degrees

2)cooling

3)180-200 degrees Constant 3-4 hours Stabilize the internal structure

2. Rough turning → Polishing

rough machining

After forging and normalizing, there is often a large amount of blank left on the surface of the workpiece. If processed directly to the drawing size, waste products will be caused due to thermal stress, thermal deformation of the workpiece, etc.

Therefore, rough machining must be carried out first, and about 2 mm of oxide scale on the surface of the forging is removed through the rough turning process.

Allowance before rough turning: 1.5mm on each side

Margin after rough turning: 0.6mm/0.4mm on each side

polishing

After rough turning, polishing is performed. Shot blasting is the surface treatment of the parts, which can remove burrs on the surface of the parts and make the surface of the parts not processed in subsequent processes more beautiful.

3. Finish turning 1→Heat treatment→Finish turning 2→Finish turning 3

This step is mainly to process according to the drawings to make the workpiece meet the standard requirements.

Purpose：

Finish turning: Meet the drawing requirements

Heat treatment: Increase the hardness of the bearing

Steps：

Finish turning step 1:  machining part channel

Heat treatment: Partially quenching the channel part to increase material hardness

Finish turning step 2: Finishing the second sequence: finishing the channel and inner contour

Finish turning step 3: Finishing the outer contour diameter, the error is controlled at ±1.5 wires (±15um)

Detailed process:

Heat treatment Inner ring

When the temperature cooling down to 360 degrees, put the bearing into the oil pool for a while to maintain hardness

Heat to 860°C 40- 50 min

Cool down to 300°C About 2 hours

Cool down to 1 80°C About 2-3 hours

medium frequency hardening

Heat to 860°C, 20~30 sec

Flush with water

Put it in the tempering furnace within 4 hours

Cool down to 180°C，2-3 hours

4. Drilling/Pulling splines

Drill the corresponding hole positions according to the part design drawings, and process the matching splines.

5. Grinding – Superfine – Washing

Grinding: grinding groove/raceway

1) Grind the outer circle first, which is the basis for grinding the groove. The accuracy is ±5um.

2) Grind the groove based on the outer circle.

Superfine: further polished with a grinder and oilstone, and the roughness is controlled at around 0.1

Washing: Washing is to remove magazines and oil on the surface of parts. The cleaning methods are mainly divided into ultrasonic oil washing, water washing, and drying.

Detailed process:

Grinding-Inner ring
Surface grinding – Noncore grinding – Coarse grinding channel -Fine grinding – Grinding the hole – Fine grinding raceway groove

Grinding-outer ring
First grinding outer diameter – Grinding groove – Fine grinding

Grinding-Flange
First grinding outer diameter – Grinding groove – Fine grinding

6.Test→Assembling→Packaging