Abstract: An electric power steering unit comprises a housing (A) for containing a rack-shaft and holding therein a coupling section of the rack-shaft to a pinion of a steering column and an electric motor equipped with a yoke (7) arranged inside the housing (A) and integrally formed therewith, and a ball screw mechanism (3) contained in a housing (B) for transmitting the rotating force of the motor to the rack-shaft as the steering assisting power. A female threaded portion (36) is formed at the end portion of yoke (7) on the housing (B) side. The female threaded portion (36) is fitted to a male threaded portion (37) formed on the end portion of housing (A) on the housing (B) side to couple the housing (A) to the housing (B). As a result, wear and adhesion are prevented as well as wall thickness is reduced with the coupling strength of the housings maintained in the electric power steering unit with a configuration in which the housings are coupled with screws.

Abstract: A power steering unit according to the invention scarcely transmits sounds and vibrations coming from the electric motor to the steering wheel of a motor vehicle. It comprises a rack-shaft 2 to be coupled to the guiding wheels of a vehicle, a housing A for slidably containing the rack-shaft 2 and holding therein a coupling section 6 for causing the teeth of the rack-shaft 2 to engage those of a pinion arranged on the steering column 5 linked to the steering handle of the vehicle and an electric motor 1 coaxially arranged around the rack-shaft 2, which the rotary force is transmitted to the rack-shaft 2 by way of a ball screw mechanism 3 as the steering assisting power. It further comprises another housing B, for rotatably supporting the nut section of the ball-and-screw mechanism 3, the housing B being provided with a fitting section to be secured to the vehicle main body.

Abstract: In an electric power steering device, a yoke made of a tubular member and carrying permanent magnets, and a hollow motor shaft coaxially and rotatably received in the yoke to carry a motor armature which cooperates with the permanent magnets to form an electric motor for the power steering device, a section of the yoke extending from an axial end thereof to a part thereof surrounding an axial end of the motor shaft defines an inner diameter which is greater than an outer diameter of the nut member so that the output torque of the electric motor can be measured during the course of assembling the power steering device by allowing a testing tool to be inserted from the open end of the yoke without any interference and to be applied to a suitable part of the nut member or the motor shaft.

Abstract: An electric power steering unit comprises a rack-shaft 2 to be coupled to the guiding wheels of a vehicle, a housing A for slidably containing the rack-shaft 2 and holding therein a coupling section 6 for causing the teeth of the rack-shaft 2 to engage those of a pinion arranged on the steering column 5 linked to the steering handle of the vehicle and an electric motor 1 coaxially arranged around the rack-shaft 2, which the rotary force is transmitted to the rack-shaft 2 by way of a ball screw mechanism 3 as the steering assisting power. A yoke 7 of the motor 1 is formed integrally with the housing A, which simplifies the shape of the yoke 7 and reduces production cost.

Abstract: In the motor armature arrangement according to the present invention, because the inner diameter (D2) of one of the axially end portions (3c) of the armature shaft (3) is reduced from the inner diameter (D1) of the motor core mounting portion (3b), the one axially end portion (3c) for mounting a bearing (8b) may be provided with a large wall thickness so that a sufficient mechanical strength can be achieved for the part for mounting the bearing without increasing the outer diameter thereof.

Abstract: An electric power steering unit comprises a rack-shaft 2 to be coupled to the guiding wheels of a vehicle, a housing A for slidably containing the rack-shaft 2 and holding therein a coupling section 6 for causing the teeth of the rack-shaft 2 to engage those of a pinion arranged on the steering column 5 linked to the steering handle of the vehicle and an electric motor 1 coaxially arranged around the rack-shaft 2, which the rotary force is transmitted to the rack-shaft 2 by way of a ball screw mechanism 3 as the steering assisting power. A nut section 19 of the ball-screw mechanism 3 is rotatably supported by a housing B separately formed from the housing A, in a state of supporting the armature shaft 11 of the electric motor 1. The rack-shaft 2 is axially movable and supported by two points of support, one at the coupling section and the other at the nut section supported by the housing B.

Abstract: An electric power steering unit includes a rack-shaft(2) to be coupled to the guiding wheels of a vehicle, a housing A for slidably containing the rack-shaft(2)and holding therein a coupling section(6)for causing the teeth of the rack-shaft(2)to engage those of a pinion arranged on the steering column(5)linked to the steering handle of the vehicle and an electric motor(1) coaxially arranged around the rack-shaft(2), which the rotary force is transmitted to the rack-shaft(2)by way of a ball screw mechanism 3 as the steering assisting power. A nut section(19)of the ball-screw mechanism(3)is rotatably supported by a housing(B) separately formed from the housing(A), in a state of supporting the armature shaft(11)of the electric motor(1). The rack-shaft(2) is axially movable and supported by two points of support, one at the coupling section and the other at the nut section supported by the housing(B).

Abstract: An electric power steering unit has an armature shaft that is free from axial forces and hence may have less rigorous requirements for its strength so that it may be manufactured more efficiently at reduced cost. It comprises a rack-shaft 2 to be coupled to the guiding wheels of a vehicle, a housing A for slidably containing the rack-shaft 2 and holding therein a coupling section 6 for causing the teeth of the rack-shaft 2 to engage those of a pinion arranged on the steering column 5 linked to the steering handle of the vehicle and an electric motor 1 coaxially arranged around the rack-shaft 2, which the rotary force is transmitted to the rack-shaft 2 by way of a ball screw mechanism 3 as the steering assisting power. A nut section 19 is linked to the armature shaft 11 of the electric motor 1 and rotatably supported by the housing B.

Abstract: In a yoke arrangement for electric motors which are particularly suitable for use in electric power steering devices, the yoke comprises a first tubular portion, a second tubular portion which has a smaller diameter than the first tubular portion, and a tapered section connecting the two tubular portions. The length of the tapered sections is desired to be minimized so that the overall length of the electric motor may be minimized. Reducing the length of the tapered section and thereby increasing the taper angle of the tapered section leads to the reduction in the mechanical strength of the yoke against an axial force. To compensate for this reduction in mechanical strength, the wall thickness of the tapered section is made larger than that of the first portion. Thus, the overall mechanical strength of the yoke can be ensured with a minimum increase in the material cost and manufacturing cost. The yoke may be formed by plastic deformation such as swaging and expansion.

Abstract: An electric motor used in an electric type power steering apparatus and the like, wherein a magnetic field unit outer casing 14 for encasing a magnetic field unit 7 comprising magnets 5 and an armature 6, is formed integral and concentric with a motor yoke 3, and a power supply unit outer casing 15 for encasing a commutator 22 and brushes 27 of a power supply unit 8, having a protruding portion 15a protruding from an axially concentric outer peripheral face thereof arranged eccentric to the magnetic field unit outer casing 14, is formed integral with the motor yoke 3. As a result, the influence of shock from the outside is suppressed, and accommodating space for the power supply unit ensured, so that long motor life is possible.

Abstract: A supporting structure for a drive shaft of an electrically driven power steering motor is presented to prevent axial displacement of the drive shaft. Around the entire peripheral outer circumference of a hollow cylindrical drive shaft, a radially protruding flange section of a U-shaped cross section is provided to engage with the shaft bearing freely rotatably supporting the drive shaft, and prevent an axial displacement of the drive shaft. The support structure exhibits little deformation due to spring back, because of the improved resistance to axial loading and retains excellent original shape of the flange section.