This torsion beam manufacturing method is a method for manufacturing a torsion beam which is provided with a uniformly shaped closed cross-sectional portion in which a cross section orthogonal to a longitudinal direction is a closed cross section having a substantial V-shape or a substantial U-shape with a pair of ear portions, and a shape changing portion which leads to the uniformly shaped closed cross-sectional portion and in which a shape of the closed cross section changes progressively away from the uniformly shaped closed cross-sectional portion, the torsion beam manufacturing method comprising: thickening to form a pair of thickened portions in at least the shape changing portion by pressurizing each of the pair of ear portions from outside against swelling of the pair of ear portions in a slate where both outer surfaces of each of the pair of ear portions are supported.

There is provided a method of manufacturing a variable wall thickness steel pipe with a hollow tubular raw pipe. The method of manufacturing a variable wall thickness steel pipe includes locking the raw pipe in a die by thrusting a plug into the raw pipe from an one end side, so as to expand an outer shape on the one end side in a state, where the raw pipe is disposed inside the die and movement of the raw pipe in a longitudinal direction is restricted; and performing ironing in which an inner shape of the raw pipe is expanded while the outer shape is maintained so that a thin portion is formed by further thrusting the plug toward the other end side of the raw pipe while the locked state of the raw pipe is maintained, whereas the restriction on the raw pipe is relaxed.

A composite member includes a metal shaft member, and a fit member having an insertion hole and secured onto the shaft member inserted in the insertion hole. The shaft member includes a receiving portion contacting a first end surface of the fit member, a first radially enlarged portion adjacent to the receiving portion in an axial direction and tightly contacting an inner peripheral surface of the insertion hole, and a second radially enlarged portion adjacent to the first radially enlarged portion in the axial direction and tightly contacting a second end surface of the fit member opposite to the first end surface. The first and second radially enlarged portions are formed by applying a compressive load in the axial direction to the shaft member and an alternating load in a direction intersecting the axial direction to a portion of the shaft member inserted in the insertion hole.

A composite member includes a metal shaft member, and a fit member having an insertion hole and secured onto the shaft member inserted in the insertion hole. The shaft member includes a receiving portion contacting a first end surface of the fit member, a first radially enlarged portion adjacent to the receiving portion in an axial direction and tightly contacting an inner peripheral surface of the insertion hole, and a second radially enlarged portion adjacent to the first radially enlarged portion in the axial direction and tightly contacting a second end surface of the fit member opposite to the first end surface. The first and second radially enlarged portions are formed by applying a compressive load in the axial direction to the shaft member and an alternating load in a direction intersecting the axial direction to a portion of the shaft member inserted in the insertion hole.

A tie rod end includes a body portion having a curved portion and extending in a rod shape, an engaging portion with a tie rod provided at one end of the body portion, and a connecting portion with a knuckle arm provided at the other end of the body portion, and constitutes a part of a vehicle steering apparatus used for steering a vehicle. The body portion made of an aluminum warm-forged material is provided so that an outer curved portion is oriented toward a front of the vehicle when attached to the vehicle. Dimension in a vehicle height direction of the body portion is larger at an inner curved portion than at the outer curved portion. It is possible to obtain the tie rod end capable of securing sufficient rigidity against stress concentration inside the curved portion.

A tie rod end includes a body portion having a curved portion and extending in a rod shape, an engaging portion with a tie rod provided at one end of the body portion, and a connecting portion with a knuckle arm provided at the other end of the body portion, and constitutes a part of a vehicle steering apparatus used for steering a vehicle. The body portion made of an aluminum warm-forged material is provided so that an outer curved portion is oriented toward a front of the vehicle when attached to the vehicle. Dimension in a vehicle height direction of the body portion is larger at an inner curved portion than at the outer curved portion. It is possible to obtain the tie rod end capable of securing sufficient rigidity against stress concentration inside the curved portion.

The prevent invention proposes to provide a method for manufacturing a constant velocity drive shaft, which can manufacture especially a constant velocity drive shaft among other drive shafts with efficiency and stable high accuracy. The method for manufacturing a constant velocity drive shaft using a closed cold forging device having a plurality of mold pairs structured with an upper mold and a lower mold, comprises a first process for processing a forming material for forming the constant velocity drive shaft to form a first forming material having first large diameter portions by applying a pressure from a first upper mold of a first mold pair and pressures from both sides of the forming material, a second process for forming a second forming material having second large diameter portions by applying a pressure from a second upper mold of a second mold pair and pressures from both sides of the first forming material with respect to the first forming material being mold-processed in the first process, and a third process for forming third large diameter portions by applying a pressure from a third upper mold of a third mold pair and pressures from both sides of the second forming material with respect to the second forming material being mold-processed in the second process.

The invention sets out a method for simply producing components which are suitable for use under high loads and risks of wear and which have a core portion which consists of a metal material and a wear-resistant layer on a peripheral surface of the core portion. To this end, there is provided according to the invention a) a core portion blank which consists of the metal material and whose dimension in a first spatial direction is greater than the desired finished dimension of the core portion of the component in the relevant spatial direction and whose dimension in a second spatial direction is smaller than the desired finished dimension of the core portion of the component in this second spatial direction; b) there is applied a material which forms the wear-resistant layer to the peripheral surface in such a manner that the material and the core portion blank form a stable composite body; and c) the composite body is shaped to form the component by the composite body being extended in the direction of the second spatial direction and being compressed in the direction of the first spatial direction until the dimensions thereof in the spatial directions at least correspond to the desired finished dimensions of the component in these spatial directions and the wear-resistant material is present on a peripheral surface of the component. Optionally, finishing processing of the component may follow.

The invention relates to a twist-axle that includes a cross-beam member and two trailing arms, each trailing arm rigidly secured to the cross-beam member in one of two connection regions of the cross-beam member or formed integrally with and extending from one of the two connection regions. The cross-beam member is formed from a tubular blank and has a torsionally elastic central portion and two torsionally stiff connection regions. The cross-beam member has a wall thickness that varies longitudinally along the length of the cross-beam member from the torsionally elastic central portion to each of the torsionally stiff connection regions.

The invention relates to a twist-axle that includes a cross-beam member and two trailing arms, each trailing arm rigidly secured to the cross-beam member in one of two connection regions of the cross-beam member or formed integrally with and extending from one of the two connection regions. The cross-beam member is formed from a tubular blank and has a torsionally elastic central portion and two torsionally stiff connection regions. The cross-beam member has a wall thickness that varies longitudinally along the length of the cross-beam member from the torsionally elastic central portion to each of the torsionally stiff connection regions.