QC/T 388-2023Bowl type expansion plug (English PDF)

3.1 Straight Direction Central Plane of Vehicle

The straight direction central plane of a motorcycle with two wheels (L1, L3) refers to the Y plane that coincides with the central plane of the rear wheel of the vehicle.

The straight direction central plane of a right three-wheeled motorcycle (L2, L5) refers to the Y plane passing through the midpoint of line segment AB. The intersection points of the intersection line between the vertical plane of the central axis of the wheels at both ends and the central plane of the two wheels and the wheel support plane are points A and B, as shown in Figure 1.

NOTE. The straight direction central plane of a right three-wheeled motorcycle is also called the longitudinal symmetry plane or the datum Y plane of a right three-wheeled motorcycle.

3.6 Steering Handle Tube

The pipe fitting that the driver grips, which has sufficient strength to control the vehicle’s direction, as shown at point A in Figure 3 -- Schematic Diagrams of Direction Handles.

3.7 Steering Handle Pipe Connection Seat

The part connected to the steering handle tube and mounted on the front fork assembly or upper triple clamp, as shown at point B in Figure 3 -- Schematic Diagrams of Direction Handles.

3.8 Threaded Sleeve

The part plug-welded to the inner sides of both ends of the steering handle tube and designed to accommodate the balance weight, as shown at point C in Figure 3 -- Schematic Diagrams of

Direction Handles.

3.9 Steering Lever Mounting Seat

The part welded together with the steering handle tube and mounted on the steering mechanism, as shown at point D in Figure 3 -- Schematic Diagrams of Direction Handles. The structure of the steering lever mounting seat is quite diverse, and the specific shape is not required; it can be defined according to the design structure.

5.1 Basic Requirements

5.1.1 The direction handle shall be manufactured according to the drawings and technical documents approved through the prescribed procedures and shall comply with the provisions of this document.

5.1.2 The centers of symmetry at both ends of the direction handle shall be located in the straight direction central plane of vehicle, with a maximum offset of no more than 2 mm. This can be measured separately for the direction handle; the measurement method is detailed in 6.6.2.

NOTE. The value measured separately for the direction handle is the offset of the direction handle from the straight direction central plane of vehicle.

5.1.3 The height difference between the left and right ends of the direction handle shall not exceed 3 mm. The measurement method is detailed in 6.6.2.

5.1.4 The surface treatment of direction handles generally uses chrome plating, baked enamel

coating, galvanizing, etc.; aluminum alloys are generally treated with anodizing, etc.

5.2 Appearance Quality of Direction Handles

5.2.1 The surface coating of direction handles shall be bright and uniform in color, free from defects such as scorching, blistering, peeling, exposed base material, obvious burrs, mottling, scratches, corrosion, etc.

5.2.2 The surface color shall be bright and consistent, the film layer shall be dense, and the paint film thickness shall be uniform. There shall be no areas without a film layer, and no defects such as contamination, looseness, dust accumulation, burns, or excessive corrosion and rust, etc.

5.3 Materials of Direction Handles

5.3.1 Split-type Direction Handle

The split-type steering handle tube is generally made of Q195 or Q235 steel pipes with a longitudinal electric (resistance) weld or #20 seamless steel pipes, which shall comply with the provisions of GB/T 13793 or GB/T 8162; the steering handle pipe connection seat is generally made of #20 or #35 forged steel parts, which shall comply with the provisions of GB/T 699; or made of 6061A aluminum alloy, which shall comply with the provisions of GB/T 3190.

5.3.2 One-piece Direction Handle

The one-piece direction handle is generally made of Q195 or Q235 steel pipes with a longitudinal electric (resistance) weld, which shall comply with the provisions of GB/T 13793;

or made of #10 or #20 seamless steel pipes for structural purposes, which shall comply with the provisions of GB/T 8162; the aluminum alloy direction handle is recommended to be made of

6061A, which shall comply with the provisions of GB/T 3190.

5.3.3 Welded Direction Handle

The welded steering handle tube and the steering lever mounting seat are generally made of

Q195 or Q235 steel pipes with a longitudinal electric (resistance) weld or seamless steel pipes for structural purposes, which shall comply with the provisions of GB/T 13793 or GB/T 8162.

The steering lever mounting seat can also be made of Q195 or Q235 steel sheets, which shall comply with the provisions of GB/T 708 and GB/T 11253.

5.4 Welding of Direction Handles

5.4.1 Split-type Direction Handle

When the steering handle tube and the steering handle pipe connection seat are welded together,

CO2 gas-shield arc welding is generally adopted, which shall comply with the provisions of

GB/T 985.1.

5.4.2 One-piece Direction Handle

When balance weights need to be added to both ends of the one-piece direction handle, threaded sleeves shall be welded to the inner sides of both ends of the direction handle; plug welding holes shall be added at appropriate positions on both ends of the direction handle, and the threaded sleeves and the direction handle shall be welded together. Plug welding is recommended and shall comply with the provisions of GB/T 985.1.

5.4.3 Welded Direction Handle

When the steering handle tube and the steering lever mounting seat are welded together, CO2 gas-shield arc welding is generally adopted, which shall comply with the provisions of GB/T

985.1.

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