VEHICLE STEERING SYSTEM AND MANUFACTURING METHOD FOR VEHICLE STEERING SYSTEM
First Claim
1. A steer-by-wire vehicle steering system that converts rotative power of an electric motor into a movement of a steered shaft in an axial direction via a ball screw mechanism, the vehicle steering system comprising:
- a threaded shaft provided at an intermediate part of the steered shaft;
a ball nut screwed to the threaded shaft via balls and rotatable together with a rotor of the electric motor;
a tubular housing that houses the electric motor and the ball nut and through which the steered shaft is passed; and
first and second stoppers arranged at first and second end portions of the housing, respectively,wherein the steered shaft has first and second contact portions located respectively at first and second end portions of the threaded shaft,radial gaps are formed between outer peripheries of the respective contact portions and an inner periphery of the rotor so that the each of the contact portions is allowed to be inserted into the rotor, andwhen the steered shaft moves in the axial direction, one of the contact portions, which is on a moving direction side and passed through the rotor, contacts a corresponding one of the stoppers, so that a travel amount of the steered shaft in the axial direction is restricted.
1 Assignment
0 Petitions
Accused Products
Abstract
Provided is a vehicle steering system that is able to restrict a travel amount of a steered shaft in a housing, that is small and that has an excellent strength. The vehicle steering system is a steer-by-wire vehicle steering system that converts rotative power of electric motors into a movement of a steered shaft in an axial direction via a ball screw mechanism. One of contact portions at respective ends of a screw shaft at an intermediate part of the steered shaft passes through a rotor based on a moving direction of the steered shaft so as to contact a corresponding one of the corresponding stoppers thereby restricting a travel amount of the steered shaft. The stoppers are made of a material different from that of the housing and having a high strength.
17 Citations
15 Claims
-
1. A steer-by-wire vehicle steering system that converts rotative power of an electric motor into a movement of a steered shaft in an axial direction via a ball screw mechanism, the vehicle steering system comprising:
-
a threaded shaft provided at an intermediate part of the steered shaft; a ball nut screwed to the threaded shaft via balls and rotatable together with a rotor of the electric motor; a tubular housing that houses the electric motor and the ball nut and through which the steered shaft is passed; and first and second stoppers arranged at first and second end portions of the housing, respectively, wherein the steered shaft has first and second contact portions located respectively at first and second end portions of the threaded shaft, radial gaps are formed between outer peripheries of the respective contact portions and an inner periphery of the rotor so that the each of the contact portions is allowed to be inserted into the rotor, and when the steered shaft moves in the axial direction, one of the contact portions, which is on a moving direction side and passed through the rotor, contacts a corresponding one of the stoppers, so that a travel amount of the steered shaft in the axial direction is restricted. - View Dependent Claims (2, 3, 4, 5, 6, 12, 13)
-
-
7. A manufacturing method for a steer-by-wire vehicle steering system that converts rotative power of an electric motor into a movement of a steered shaft in an axial direction via a ball screw mechanism, the manufacturing method comprising:
-
a temporarily-fitting step of loosely fitting first and second stoppers for restricting an axial travel amount of the steered shaft, to loose fit portions of fitting surfaces respectively formed at first and second end portions of a tubular housing; and a fully-fitting step of reciprocating the steered shaft in the axial direction, thereby tightly fitting the stoppers to tight fit portions of the corresponding fitting surfaces by first and second contact portions located at first and second end portions of a threaded shaft of the steered shaft. - View Dependent Claims (8, 9, 10, 11, 14, 15)
-
Specification