Bearing hole features  

  With the rapid development of new energy vehicles, the Chinese people have higher requirements for various performances of automobiles, especially for the transmission performance of automobiles, and the transmission is the key component of rotation, and its bearing mounting hole plays a vital role in the transmission, not only bearing and supporting the transmission mechanism, but also ensuring the stable operation and extending the service life of the transmission through the lubrication and sealing mechanism. And this depends on the accuracy of the bearing mounting hole and the shape tolerance of the tool.

  With the professional PCD team of PUK, we developed a solution for the above customer pain points, and after repeated testing, we launched the guide strip type PCD hinge (see Figure 1), which fully meets the dimensional tolerance and shape tolerance of the precision machined bearing hole, and also takes into account the cost of hole machining. It not only solves the precision problems that have been bothering customers, but also brings cost savings to customers.

Three common machining methods for high-precision holes

1. Fine boring tool: The diameter is adjustable, with replaceable cutting edges, and the cost is relatively low. However, the machining efficiency is low. The shape and position tolerance is not as good as that of the multi-edged铰刀.
2. Welded PCD multi-blade cutter:孔径 tolerance and shape tolerance are very good, efficient.孔 tolerance and behavior tolerance can be well guaranteed, efficient, but size is fixed, not very flexible.
3. Guide bar type reamer: adjustable size, with guide bar support, can well guarantee the hole diameter tolerance and shape tolerance.

The processing difficulties of the bearing housing mounting hole in the new energy vehicle transmission can be expressed with three "highs", high tolerance grade, high cylinderity, and high roughness.
The processing difficulties of the case of Pu Precision are as follows (see the above picture):

1. Tolerance of hole diameter ±0.011
2. Roundness 0.05; Perpendicularity 0.025; Cylindricity 0.1
3. Interference depth 208 long
4. Bottom of hole R corner

 Design with Puk precision knife (see Fig. 3)

Considering the serious interference, the long tool overhang, the difficulty in controlling the runout, and the high requirements for hole diameter and shape tolerance. The solutions are as follows:

1. Use a guide bar type lathe (diameter adjustable, guide bar support to ensure shape and position tolerance requirements)
2. Adopt adjustable tool holder (guarantee end cutting edge play)
3. Optimize edge treatment

 Application Case 

• Cutting tool specifications: D27
• Part name: Shell change
• Part material: A380
• Material hardness: HB74
• Cutting depth: 22mm
• Interference depth: 210mm
• Machine tool: horizontal machining center
• Main spindle interface: HSK63A
• Blade Handle: Adjustable Blade Handle
• Cold:  Inner cold

YP guide groove铰刀; three-coordinate report

Yield point groove铰刀 processed after hole detail amplification

Opponent guideAfter milling, the hole is enlarged