Abstract: An electric power steering system includes: a steered shaft, a housing containing the steered shaft therein in a movable manner; a ball screw nut engaged threadedly to the steered shaft via a plurality of balls and configured to move the steered shaft in an axial direction; a double row angular contact ball bearing configured to retain the ball screw nut and to support the retained ball screw nut rotatably relative to the housing; a wall portion placed at either side of the double row angular contact ball bearing in the axial direction of the steered shaft, the wall portion being formed integrally with the housing; and an elastic member provided between the wall portion and the outer ring portion and configured to retain the double row angular contact ball bearing to be elastically displaceable in the axial direction.

Abstract: A drainage device of an electric power steering system has a drain case and a drain valve. The drain case has a groove portion formed in a peripheral edge portion of a case inlet. The drain valve has a main body, and a flange disposed so as to face the case inlet. The flange has a bulged portion bulged toward the case inlet, and an annular seal portion. When the seal portion is brought into tight contact with the peripheral edge portion of the case inlet, the drainage device is placed in a valve closed state to form an annular space between the groove portion and the seal portion. When the seal portion is elastically deformed to form a gap between the seal portion and the peripheral edge portion of the case inlet, the drainage device is placed in a valve open state.

Abstract: An electric power steering system includes: a steered shaft, a housing containing the steered shaft therein in a movable manner; a ball screw nut engaged threadedly to the steered shaft via a plurality of balls and configured to move the steered shaft in an axial direction; a double row angular contact ball bearing configured to retain the ball screw nut and to support the retained ball screw nut rotatably relative to the housing; a wall portion placed at either side of the double row angular contact ball bearing in the axial direction of the steered shaft, the wall portion being formed integrally with the housing; and an elastic member provided between the wall portion and the outer ring portion and configured to retain the double row angular contact ball bearing to be elastically displaceable in the axial direction.

Abstract: A steering system includes a rack housing and a drainage device. The drainage device has a drainage case, and a drainage valve made of a resin. The drainage case has a case inlet port communicated with a housing space of the rack housing, case outlet ports communicated with the outside of the rack housing, a drainage space communicated with the case inlet port and the ease outlet ports, and a convex portion. The drainage valve has a valve body inlet port portion, and a valve body outlet port portion that interrupts communication between the case inlet port and the case outlet ports when the valve body outlet port portion comes into contact with the convex portion.

Abstract: A drainage device of an electric power steering system has a drain case and a drain valve. The drain case has a groove portion formed in a peripheral edge portion of a case inlet. The drain valve has a main body, and a flange disposed so as to face the case inlet. The flange has a bulged portion bulged toward the case inlet, and an annular seal portion. When the seal portion is brought into tight contact with the peripheral edge portion of the case inlet, the drainage device is placed in a valve closed state to form an annular space between the groove portion and the seal portion. When the seal portion is elastically deformed to form a gap between the seal portion and the peripheral edge portion of the case inlet, the drainage device is placed in a valve open state.

Abstract: A steering system includes a rack housing and a drainage device. The drainage device has a drainage case, and a drainage valve made of a resin. The drainage case has a case inlet port communicated with a housing space of the rack housing, case outlet ports communicated with the outside of the rack housing, a drainage space communicated with the case inlet port and the ease outlet ports, and a convex portion. The drainage valve has a valve body inlet port portion, and a ‘valve body outlet port portion that interrupts communication between the case inlet port and the case outlet ports when the valve body outlet port portion comes into contact with the convex portion.