Forming methods of one-piece weldless wheels made of metal sheets including the steps of rolling, forming a primary wheel rim and a primary wheel disc, roll forming, compressing and shaping, in order to obtain one-piece weldless wheels. The methods can form weldless wheels by rolling, cold roll forming and cold extruding, which can reduce energy consumption by 45-55% and cut down material cost by 5-15% while improving strength of the wheel by 20-30%. A wheel with different thicknesses can be formed by the methods and can meet the requirements on mechanical strength. The methods can improve the precision of the wheel and minimize the swing value and jerk value. The wheel produced is safer, and the regular air tight test on the wheel is not necessary.

A forging and inclined window hole punching composite die includes an upper die holder, a connection sleeve, an upper die sliding sleeve, a pressure plate, inclined window puncher pins, a center puncher pin, first connection screw rods, first springs, second connection screw rods, second springs, hydraulic assistant systems, a lower die and a bottom plate. Bottom surface of the pressure plate of the composite die is a plane to avoid deformation of a front molding surface. Hydraulic power is added to the inclined window puncher pins to increase the pressure for punching inclined holes, avoid quality problems and increase a demolding force. A multi-split synchronous hydraulic device may well realize synchronization of the plurality of inclined window puncher pins.

In a brake-disc intermediate product, a corrugated portion is molded using an upper mold and a lower mold. The brake-disc intermediate product is set in a mold, the mold has a slope corresponding to the corrugated portion, and an angular portion formed along the outer circumferential edge of the corrugated portion is in contact with the slope in a state where the brake-disc intermediate product is set in the mold. The angular portion in contact with the slope is deformed by pressing the brake-disc intermediate product in a direction of the mold, to mold a chamfer portion. The slope is formed so that a chamfering angle formed with respect to an inner bottom surface of the mold is larger at a portion in contact with the concave portion than a chamfering angle at a portion in contact with the convex portion.

A tool-transition-free machining method includes: first, a primary turning is conducted, then holes are drilled out by a machining center, and finally a secondary turning is conducted.

A tool-transition-free machining method includes: first, a primary turning is conducted, then holes are drilled out by a machining center, and finally a secondary turning is conducted.

A grounding spacer is provided. The grounding spacer comprising a circular body having a top surface, a bottom surface, and a central aperture, and a plurality of radially spaced penetration features, wherein at least one of the penetration features has at least a portion thereof extending from the top surface, and wherein at least one of the penetration features has at least a portion thereof extending from the bottom surface.

A forging and inclined window hole punching composite die includes an upper die holder, a connection sleeve, an upper die sliding sleeve, a pressure plate, inclined window puncher pins, a center puncher pin, first connection screw rods, first springs, second connection screw rods, second springs, hydraulic assistant systems, a lower die and a bottom plate. Bottom surface of the pressure plate of the composite die is a plane to avoid deformation of a front molding surface. Hydraulic power is added to the inclined window puncher pins to increase the pressure for punching inclined holes, avoid quality problems and increase a demolding force. A multi-split synchronous hydraulic device may well realize synchronization of the plurality of inclined window puncher pins.

A tool-transition-free machining method includes: first, a primary turning is conducted, then holes are drilled out by a machining center, and finally a secondary turning is conducted.

A tool-transition-free machining method includes: first, a primary turning is conducted, then holes are drilled out by a machining center, and finally a secondary turning is conducted.

A grounding spacer is provided. The grounding spacer comprising a circular body having a top surface, a bottom surface, and a central aperture, and a plurality of radially spaced penetration features, wherein at least one of the penetration features has at least a portion thereof extending from the top surface, and wherein at least one of the penetration features has at least a portion thereof extending from the bottom surface.