Hollow steering rack bar and its manufacturing method
AssigneeNeturen Co., Ltd.
InventorKeita Ozeki
Life of this patent
Estimating the term…
Abstract
Described is a steering rack bar which is low in costs, which is hollowed in overall length, and for use in steering equipment for automobiles. A rack is formed on a first steel tube by plastic working, wherein the first steel tube has good plastic workability by low carbon content, and has high strength after hardening. The above first steel tube and a second steel tube are joined to complete a hollow steering rack bar, wherein the second steel tube has a higher carbon content and is lower in cost than the first steel tube. Moreover, the second steel tube which has a margin of the strength can be thinner than the first steel tube for reduction of weight.
Claims43
A steering rack bar, which is hollowed in an overall length, and has a rack on a part of the length:
- wherein
- the rack bar is comprised of a rack-formed section and a non-rack-formed section, wherein the rack-formed section contains one end of the rack bar, the rack and a portion of a succeeding circular cross-sectional part, and the non-rack-formed section contains a residual length other than the rack-formed section;
- and
- the rack bar is constructed by joining the rack-formed section and the non-rack-formed section, wherein constituents of steels are different between the rack-formed section and the non-rack-formed section and carbon content of the non-rack-formed section is higher than that of the rack-formed section.
A steering rack bar, which is hollowed in an overall length, and has a rack on a part of the length:
- wherein
- the rack bar is comprised of a rack-formed section and a non-rack-formed section, wherein the rack-formed section contains one end of the rack bar, the rack and a portion of a succeeding circular cross-sectional part, and the non-rack-formed section contains a residual length other than the rack-formed section;
- and
- the rack bar is constructed by joining the rack-formed section and the non-rack-formed section, wherein the thickness of the non-rack-formed section is smaller than the thickness of the circular cross-sectional part of the rack-formed section.
A method of manufacturing a hollow steering rack bar, the method comprising:
- forming a rack on a first steel tube by plastic working, wherein the rack is not formed at least in one end part of the first steel tube;
- and
- joining the first steel tube on which is formed said rack and a second steel tube by butting said one end part of the first steel tube and an end of the second steel tube, wherein constituents of steels are different between the first steel tube and the second steel tube, with carbon content of the second steel tube being higher than that of the first steel tube.
A method of manufacturing a hollow steering rack bar, the method comprising:
- forming a rack on a first steel tube by plastic working, wherein the rack is not formed at least in one end part of the first steel tube;
- and
- joining the first steel tube on which is formed said rack and a second steel tube by butting said one end part of the first steel tube and an end of the second steel tube, wherein the second steel tube is thinner than the first steel tube.
A method of manufacturing a hollow steering rack bar, the method comprising:
- forming a rack on a first steel tube by plastic working, wherein the rack is not formed at least in one end part of the first steel tube;
- and
- joining the first steel tube on which is formed said rack and a second steel tube by butting said one end part of the first steel tube and an end of the second steel tube, wherein outer diameters of the first steel tube and the second steel tube are different.
Dependencies are inferred from the claim text.