Hollow rack shaft

A method of manufacturing a hollow rack shaft which is formed cylindrically by bending the opposite sides of a substantially rectangular plate so that the sides are joined and in a part of the surface of which a row of rack teeth along a direction of-the axis is formed, wherein:

• a complementary profile composed of the continuation of a convex portion and a concave portion is provided to said respective sides;
• and
• the respective sides are joined owing to this profile when they are confronted so that they are not detached.

A hollow rack shaft which is formed cylindrically by bending a substantially rectangular plate so that the parallel two sides are joined and in a part of the surface of which a row of rack teeth along a direction of the axis is formed, wherein:

• said plate is one plate acquired by welding a first plate for a rack teeth area for said row of rack teeth is to be formed and a second plate for an area except it.

A method of manufacturing a hollow rack shaft provided a row of rack teeth along a direction of the axis in a part of the surface for forming a substantially rectangular plate cylindrically by bending it so that the parallel two sides are joined, wherein:

• said plate is one plate acquired by welding a first plate for a rack teeth area for said row of rack teeth to be formed and a second plate for an area except it.

A method of manufacturing a hollow rack shaft which is provide with a first area and a second area on both sides of it, in which in said first area, a row of rack teeth and a semi-cylindrical part on the reverse side are formed and in which in said two second areas, a complete cylindrical part is formed and at least one of the second areas has a diameter different from the diameter of the semi-cylindrical part in said first area, wherein:

• a plate provided with a part with first width having width corresponding to the first area for said row of rack teeth to be formed and a part with second width corresponding to said second area and having narrower width than said part with the first width is plastically deformed cylindrically.