Bearing Drawing Symbol Guide: From Beginner to Advanced

1. Comprehensive Bearing Drawing Symbols and Interpretation

The symbol system in bearing drawings is standardized by national standards (GB/T 272-2017), covering key parameters such as type, size, and tolerance. Below are the core symbol categories and their meanings:

1. Basic Codes

Type Code (First Digit/Letter):

6: Deep groove ball bearing (e.g., 6204) 3: Tapered roller bearing (e.g., 30213) N: Cylindrical roller bearing (e.g., NU105) 7: Angular contact ball bearing (e.g., 7214C)

Size Series Code (Middle Two Digits):

First Digit: Width/Height Series (e.g., "3" indicates medium series) Second Digit: Diameter Series (e.g., "2" indicates light series)

Inner Diameter Code (Last Two Digits):

General Rule: Inner diameter = Code × 5 (e.g., 04 → 20mm, 12 → 60mm) Exceptions: Inner diameter < 10mm is directly shown (e.g., 608Z → 8mm)

2. Postfix Codes (Auxiliary Parameters)

Seals and Dust Protection:

Z: Single-side dust cover; 2Z: Double-side dust cover; RS: Contact rubber seal

Clearance Level:

/C1~C5: Clearance from small to large (C3 is the common group)

Tolerance Level:

/P0~P6: Accuracy from low to high (P0 is standard grade, P6 is high precision)

Cage Material:

M: Brass; T: Phenolic resin; V: No cage (full roller)

2. Quick Interpretation of Bearing Drawings

1. Step-by-Step Breakdown Method

2. Example Analysis

3. Bearing Processing Symbols and Process Key Points

1. Processing Symbols Explained

Form and Position Tolerances: Denote roundness, parallelism, etc. (e.g., ◎ indicates coaxiality).

Surface Roughness: Ra value indicates processing accuracy (e.g., Ra0.8 indicates precision grinding).

Heat Treatment Mark: For example, “HRC58-62” indicates a quenching hardness range.

2. Processing Technical Requirements

Material Selection:

High carbon chromium steel (e.g., GCr15) is a common material.

Precision Control:

4. Bearing Drawing Drawing Standards and Norms

1. Drawing Method Classification (GB/T 4459.7)

General Drawing Method: Simplified representation, only a rectangle and axis lines are used to indicate bearing position.

Feature Drawing Method: Indicates rolling element type (ball/roller) and contact angle, suitable for assembly drawings.

Regulated Drawing Method: Detailed drawings of inner and outer rings, cage structure, used for product drawings and manuals.

2. Standardization of Marking Terms

Material Marking: For example, GCr15 (high carbon chromium bearing steel).

Load Parameters: Basic dynamic load rating (Cr), static load rating (Cor), e.g., “Cr = 30.8KN”.

Mastering the bearing drawing symbol system and interpretation methods is a core skill for equipment selection, maintenance, and processing. Through the symbol analysis, examples, and process key points in this article, you can quickly improve drawing reading efficiency and process design levels.

Let the passion for innovation at Yun Technology burn forever, providing free knowledge and technical services suitable for bearing operating conditions to help extend bearing life more scientifically. Let Yun Technology make bearing movement more scientific.

If you would like to learn more about bearing system solutions, feel free to contact us. National hotline: 4006-808-505, Industry bearing technician: Manager Li: 13657445999.