Abstract: A rack bar blank material includes a rack portion configured to mesh with a pinion in an end side of a hollow shaft material in an axial direction, and an end portion which is provided closer to the end side of the hollow shaft material than the rack portion. The end portion has a diameter which is larger than that of a minimum circle embracing a section of the rack portion which is perpendicular to the axial direction and which is equal to that of a shaft portion at the other end side of the shaft material in the axial direction.

Abstract: A manufacturing method for a hollow rack bar made of a hollow shaft material and including a toothed section which has a rack on an outer surface and a shaft section which is formed thinner than the toothed section, the manufacturing method includes drawing the hollow shaft material by using a die and a plug, and preforming regions of the hollow shaft material including a toothed section forming region configured to form the toothed section and a shaft section forming region configured to form the shaft section to have thicknesses according to the regions respectively, and forming the rack at the toothed section forming region of the hollow shaft material which is preformed.

Abstract: A method for manufacturing a rack bar includes joining axial end portions of first and second bar members to each other, and forming a power transmission section on the second bar member. The first bar member has a toothed portion. When the second bar member is hollow, the method may further include thickening a wall of a portion of the second bar member along the axial direction so as to be coaxial with the first bar member. When the second bar member has a greater diameter than the first bar member, the method may further include cutting an outside diameter of a portion of the second bar member in the axial direction so as to be coaxial with the first bar member. The power transmission section is formed on the portion of the second bar member where the wall has been thickened and/or the outside diameter has been cut.

Abstract: A method of fabricating a rack, the method includes: supporting a first rack bar having a first toothed part on a shaft of the first rack bar; supporting a second rack bar having a second toothed part on a shaft of the second rack bar such that an axial center line of the second rack bar coincides with an axial center line of the first rack bar; supporting a joint member between the first and second rack bars such that an axial center line of the joint member coincides with the axial center lines of the first and second rack bars; rotating the joint member about the axial center lines of the first and second rack bars relative to the first and second rack bars; and bringing an end of the first rack bar and an end of the second rack bar into friction pressure welding with the joint member.

Abstract: A rack bar includes a shaft member having a toothed section. The toothed section has a plurality of rack teeth, and extends over a portion of an entire length of the shaft member along a longitudinal direction of the shaft member. The shaft member has a grinding-finished outer peripheral surface extending over the entire length of the shaft member including the toothed section. A method for manufacturing the rack bar includes forming the toothed section by plastic working and grinding the outer peripheral surface to improve shape accuracy.

Abstract: A method for manufacturing a rack bar includes joining axial end portions of first and second bar members to each other, and forming a power transmission section on the second bar member. The first bar member has a toothed portion. When the second bar member is hollow, the method may further include thickening a wall of a portion of the second bar member along the axial direction so as to be coaxial with the first bar member. When the second bar member has a greater diameter than the first bar member, the method may further include cutting an outside diameter of a portion of the second bar member in the axial direction so as to be coaxial with the first bar member. The power transmission section is formed on the portion of the second bar member where the wall has been thickened and/or the outside diameter has been cut.

Abstract: Provided is a hollow rack bar including a rack portion that is engaged with a pinion gear and faces supported by a yoke. The hollow rack bar includes: the rack portion engaged with the pinion gear; and the supported faces provided on a back side of teeth of the rack portion and supported by the yoke. The rack portion is formed by locating a toothed mold on an outer face of a circular tube material, and inserting a cored bar into the circular tube material to pressurize an inner face, thereby transferring a shape of the toothed mold. The supported faces are formed by removal processing or deformation processing of a back side of the teeth rack portion of the circular tube material.

Abstract: Provided are a method of manufacturing a hollow rack bar including a rack portion that is engaged with a pinion gear and faces supported by a yoke easily and accurately, and the hollow rack bar. The hollow rack bar (10) includes: the rack portion (21) engaged with the pinion gear (29); and the supported faces (23) provided on a back side of teeth of the rack portion (21) and supported by the yoke (31). The rack portion (21) is formed by locating a toothed mold (39) on an outer face of a circular tube material, and inserting a cored bar (41) into the circular tube material to pressurize an inner face, thereby transferring a shape of the toothed mold (39). The supported faces (23) are formed by removal processing or deformation processing of a back side of the teeth rack portion (21) of the circular tube material.

Abstract: A method for manufacturing a rack bar includes joining axial end portions of first and second bar members to each other, and forming a power transmission section on the second bar member. The first bar member has a toothed portion. When the second bar member is hollow, the method may further include thickening a wall of a portion of the second bar member along the axial direction so as to be coaxial with the first bar member. When the second bar member has a greater diameter than the first bar member, the method may further include cutting an outside diameter of a portion of the second bar member in the axial direction so as to be coaxial with the first bar member. The power transmission section is formed on the portion of the second bar member where the wall has been thickened and/or the outside diameter has been cut.

Abstract: A rack bar includes a shaft portion and a rack toothed portion provided on the shaft portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion to mesh with a pinion gear. Each of the rack teeth includes a tooth tip portion, a contact face arranged obliquely relative to the axial direction and configured to contact the pinion gear, and a rounded corner portion between the tooth tip portion and the contact face. A first radius defining a central area of the rounded corner portion with respect to a tooth width direction is larger than a second radius defining another area of the rounded corner portion other than the central area.

Abstract: A method of fabricating a rack, the method includes: supporting a first rack bar having a first toothed part on a shaft of the first rack bar; supporting a second rack bar having a second toothed part on a shaft of the second rack bar such that an axial center line of the second rack bar coincides with an axial center line of the first rack bar; supporting a joint member between the first and second rack bars such that an axial center line of the joint member coincides with the axial center lines of the first and second rack bars; rotating the joint member about the axial center lines of the first and second rack bars relative to the first and second rack bars; and bringing an end of the first rack bar and an end of the second rack bar into friction pressure welding with the joint member.

Abstract: A hollow rack bar and a method of manufacturing the hollow rack bar are provided. The hollow rack bar includes a hollow blank pipe portion having a uniform wall thickness, and a rack toothed portion. The rack toothed portion includes teeth, a flat portion having a flat surface and arranged side by side with the teeth in a direction along a center axis of the blank pipe portion, and a slanted portion provided at an end of the flat portion with respect to a direction perpendicular to the center axis and arranged to be lower than the flat portion. A length of the slanted portion projected on a straight line perpendicular to the center axis and parallel to the surface of the flat portion is longer than zero and equal to or shorter than the wall thickness of the blank pipe portion.

Abstract: A rack bar includes a shaft member having a toothed section. The toothed section has a plurality of rack teeth, and extends over a portion of an entire length of the shaft member along a longitudinal direction of the shaft member. The shaft member has a grinding-finished outer peripheral surface extending over the entire length of the shaft member including the toothed section. A method for manufacturing the rack bar includes forming the toothed section by plastic working and grinding the outer peripheral surface to improve shape accuracy.

Abstract: Provided are a method of manufacturing a hollow rack bar including a rack portion that is engaged with a pinion gear and faces supported by a yoke easily and accurately, and the hollow rack bar. The hollow rack bar (10) includes: the rack portion (21) engaged with the pinion gear (29); and the supported faces (23) provided on a back side of teeth of the rack portion (21) and supported by the yoke (31). The rack portion (21) is formed by locating a toothed mold (39) on an outer face of a circular tube material, and inserting a cored bar (41) into the circular tube material to pressurize an inner face, thereby transferring a shape of the toothed mold (39). The supported faces (23) are formed by removal processing or deformation processing of a back side of the teeth rack portion (21) of the circular tube material.

Abstract: A rack manufacturing apparatus and a rack manufacturing method are provided. The rack manufacturing apparatus includes a first support portion configured to support a hollow or solid first bar on which first rack teeth are formed, a second support portion configured to support a hollow or solid second bar such that an axial center line of the second bar is aligned with an axial center line of the first bar, a base configured to cause the second support portion to approach the first support portion, and a rotary driving portion configured to rotate the second support portion about the axial center line of the second support portion relative to the first support portion so as to join an end portion of the first bar and an end portion of the second bar by a friction pressure welding.

Abstract: A rack manufacturing apparatus and a rack manufacturing method are provided. The rack manufacturing apparatus includes a first support portion configured to support a hollow or solid first bar on which first rack teeth are formed, a second support portion configured to support a hollow or solid second bar such that an axial center line of the second bar is aligned with an axial center line of the first bar, a base configured to cause the second support portion to approach the first support portion, and a rotary driving portion configured to rotate the second support portion about the axial center line of the second support portion relative to the first support portion so as to join an end portion of the first bar and an end portion of the second bar by a friction pressure welding.

Abstract: A rack bar includes a shaft portion and a rack toothed portion provided on the shaft portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion to mesh with a pinion gear. Each of the rack teeth includes a tooth tip portion, a contact face arranged obliquely relative to the axial direction and configured to contact the pinion gear, and a rounded corner portion between the tooth tip portion and the contact face. A first radius defining a central area of the rounded corner portion with respect to a tooth width direction is larger than a second radius defining another area of the rounded corner portion other than the central area.

Abstract: A rack bar includes a shaft portion, a rack toothed portion provided on the shaft portion, and a dummy toothed portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion, each of the rack teeth including a contact face arranged obliquely relative to the axial direction to contact the pinion gear. The dummy toothed portion includes at least one dummy tooth provided on at least one side of the rack toothed portion in the axial direction such that the dummy tooth is arranged parallel to and next to the rack teeth. The dummy tooth is designed such that a whole height of the dummy tooth is smaller than a whole height of each of the rack teeth.

Abstract: Method of fabricating a rack including: supporting a first rack bar 12A having a first toothed part 12a on a shaft of the first rack bar; supporting a second rack bar 12B having a second toothed part 12b on a shaft of the second rack bar such that an axial center line of the second rack bar coincides with an axial center line of the first rack bar; supporting a joint member 15 between the first and second rack bars such that an axial center line of the joint member coincides with the axial center lines of the first and second rack bars; rotating the joint member 15 about the axial center lines of the first and second rack bars relative to the first and second rack bars; and simultaneously bringing an end of the first rack bar and an end of the second rack bar into friction pressure welding with the joint member.

Abstract: A rack bar includes a shaft portion and a rack toothed portion provided on the shaft portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion to mesh with a pinion gear. Each of the rack teeth includes a tooth tip portion, a contact face arranged obliquely relative to the axial direction and configured to contact the pinion gear, and a rounded corner portion between the tooth tip portion and the contact face. A first radius defining a central area of the rounded corner portion with respect to a tooth width direction is larger than a second radius defining another area of the rounded corner portion other than the central area.