Abstract: A belt speed reducing apparatus for an electric power steering apparatus includes a drive pulley having a first helical gear, a driven pulley having a second helical gear and a drive belt having a third helical gear in which a relationship of tan ?<? is established between a twist angle ? of the respective helical gears and a friction coefficient ? between the first or the second helical gear and the third helical gear. Further, an electric power steering apparatus for adjusting a backlash between gears of a speed reducing apparatus brought in mesh with each other or adjusting a tension of a belt of a speed reducing apparatus.

Abstract: An electric power steering apparatus capable of outputting an auxiliary steering force by an electric motor, includes a support device (20) supporting a rack shaft (10). The rack shaft (10) has support device guide surfaces, i.e., rolling surfaces (10b, 10b) extending in a longitudinal direction in at least two portions on an outer peripheral surface. The support device (20) has cylindrical rollers (23) rolling on the rolling surfaces (10b, 10b) in directions intersecting each other while pressing the rolling surfaces in a case where the rack shaft (10) is viewed in the longitudinal direction. Therefore, the rack shaft (10) can be supported by the cylindrical rollers (23) with a low friction, and the rolling surfaces (10b, 10b) provided on the outer peripheral surface of the rack shaft (10) are pressed by the cylindrical rollers (23), whereby the rack shaft (10) can be supported from two different directions.

Abstract: A frictional roller transmission comprises a first roller and a second roller disposed around two shafts which are separated from each other in such a manner that the two rollers are not brought into contact, a third roller and a fourth roller which are brought into contact with both the first and second rollers and are disposed between the first roller and the second roller and on an opposite side over a line connecting the center of the first roller and that of the second roller. An angle made by a tangential line between the first roller and the third roller (or the fourth roller) and a tangential line between the second roller and the third roller (or the fourth roller) is set at two times as large as an angle of friction obtained from a coefficient of friction between the respective rollers or smaller.

Abstract: An electric power steering apparatus can correspond to high output ability, and has a power transmission mechanism of an electric driving section capable of achieving predetermined slip torque in spite of change of operating temperature. Also, a resin gear for power transmission is formed by joining a core metal and a resin with strong bonding force, and has preferable heat-dissipation property. This joining is performed by way of chemical bond according to composite molding technique or adhesive.

Abstract: A frictional roller transmission comprises a first roller and a second roller disposed around two shafts which are separated from each other in such a manner that the two rollers are not brought into contact, a third roller and a fourth roller which are brought into contact with both the first and second rollers and are disposed between the first roller and the second roller and on an opposite side over a line connecting the center of the first roller and that of the second roller. An angle made by a tangential line between the first roller and the third roller (or the fourth roller) and a tangential line between the second roller and the third roller (or the fourth roller) is set at two times as large as an angle of friction obtained from a coefficient of friction between the respective rollers or smaller.

Abstract: An electric power steering apparatus can correspond to high output ability, and has a power transmission mechanism of an electric driving section capable of achieving predetermined slip torque in spite of change of operating temperature. Also, a resin gear for power transmission is formed by joining a core metal and a resin with strong bonding force, and has preferable heat-dissipation property. This joining is performed by way of chemical bond according to composite molding technique or adhesive.

Abstract: A torque sensor which does not require complicated neutral adjustment using a position adjustment mechanism or the like, which is capable of reducing cost and heat generation, improving reliability and realizing a one-system detection circuit. A torque sensor has a control calculating portion for varying operation timing of a coil for detecting torque and sample holding timing and a storage portion for storing an initial value of each element of the torque sensor. The torque is detected on the basis of sampling of transition voltage of the coil and a comparison with the initial value in the storage portion is made during detection of the torque is not being performed so that a failure of each element of the torque sensor is detected. Another torque sensor structured to detect torque in accordance with transient voltages which are generated in the portion in which coils and electric resistors are connected to each other is enabled to detect an abnormality of short circuit between a pair of the coils.

Abstract: An electric power steering apparatus has a torque sensor which, if the torsion of a torsion bar is within a predetermined angle, linearly outputs a detection signal converted by a first conversion ratio with respect to the torsion, and if the torsion has exceeded the predetermined angle and is within a limit angle, the torsion sensor outputs a detection signal converted by a second conversion ratio which is lower than the first conversion ratio. Further, if the detection signal has exceeded an upper threshold or dropped below a lower threshold, which thresholds being set outside the range of the detection signal outputted from the torsion sensor in its normal state in which the torsion of the torsion bar is within the limit angle, a determination is made that an abnormality has occurred in the torsion sensor.

Abstract: A torque sensor having a plurality of axial grooves formed on an outer circumferential surface of the end portion of a first rotation shaft to which a cylindrical member is fixed so as to be extended in an axial direction of the first rotation shaft. A circumferential groove is continuously and circumferentially formed on the outer circumferential surface of the end portion of the first rotation shaft. A plurality of protrusions are formed on an inner circumferential surface of the cylindrical member to be fitted into the plurality of axial grooves respectively to thereby prevent a rotation of the cylindrical member relative to the first rotation shaft. A portion of the cylindrical member which is disposed outward of the circumferential groove is deformed to fit into the circumferential groove to thereby prevent an axial displacement of the cylindrical member relative to the first rotation shaft. Further, a coil unit having a coil is disposed so as to enclose a second rotation shaft.

Abstract: A frictional transmission comprises first and second rotary shafts arranged in directions in which the central axes thereof crossed each other, a roller supported coaxially with the first rotary shaft for rotating with the first rotary shaft, a first frictional surface provided on the roller coaxially with the first rotary shaft, a disc supported coaxially with the second rotary shaft for rotating with the second rotary shaft, and a second frictional surface provided on this disc coaxially with the second rotary shaft. The second frictional surface and the first frictional surface are brought into frictional engagement with each other. A loading cam device is arranged so as to press the second frictional surface toward the first frictional surface at the time of driving. A further disc coaxial with the aforementioned disc is disposed in the environs of the second rotary shaft, and the roller is sandwiched by and between the two discs.

Abstract: The device of this invention is provided with a disc-shaped spring having an outer peripheral portion placed into contact with an outer race of a bearing and a tapered portion placed into contact with an end portion of a coil yoke, with the configuration being such that the coil yoke is wedged between a concavity 1d of the housing and the upper edge by the elastic force of the disc-shaped spring. It is therefore possible to fix the coil yoke within the housing without having to provide extra components such as a snap ring, which facilitates machining and assembly. In addition, the sealing effect can be increased by placing the disc-shaped spring into contact with the entire periphery of the outer race of the bearing, thus efficiently preventing the intrusion of impurities.

Abstract: Two coaxial circumferential grooves formed apart from each other in an axial direction are provided for a coil bobbin made of a non-conductive material, such as plastic, and arranged to be secured in a housing coaxially with an input shaft and an output shaft. Moreover, a torque detection coil is wound around each of the circumferential grooves. A terminal mounting portion is formed on the end surface of a connecting portion facing outwards in the radial direction to further outwardly project in the radial direction. Three metal terminals are secured to the upper surface of the terminal mounting portion. An end of one of the coils is wound around the first terminal, an end of the other coil is wound around the second terminal, and other ends of the two coils are wound around the third terminal.

Abstract: A torque sensor including a coil bobbin around which a coil is wound, a coil yoke having a first end face and a second end face, the coil yoke accommodating the coil bobbin, a housing having a medium-diameter portion and a small-diameter portion, the housing being shaped to receive the coil yoke and having a receiving surface at one end of the small-diameter portion, the first end face of the coil yoke abutting against the receiving surface, and a seal member that contacts the second end face of the coil yoke and urges the coil yoke toward the receiving surface to fix a position of the coil yoke in the housing, an outer peripheral surface of the seal member being secured to an inner peripheral surface of the housing at the medium-diameter portion of the housing.

Abstract: A torque sensor is provided with a pair of coils whose inductances vary in opposite directions in accordance with torque, and a differential amplifier circuit for differentially amplifying a pair of detection voltages induced by and received from the pair of coils so as to detect the torque by means of the output of the differential amplifier circuit. The torque sensor further includes a detection circuit using the detection voltage as an input to send out a detection signal when the input exceeds a predetermined upper limit value or becomes lower than a predetermined lower limit value, and a control circuit for controlling the differential amplifier circuit on receiving the detection signal so that the output of the differential amplifier circuit has a predetermined value outside a steady output range.

Abstract: The torque sensor of the present invention converts the torsion of a shaft into an amount of movement of a slider member and detects the amount of movement of the slider member as a variation in the self-inductance of a detection coil unit. The detection coil unit is a bobbin having a coil wound thereon. The bobbin has a cylindrical portion, first and second annular flange portions provided on axially opposite ends of the cylindrical portion, and a third annular flange portion provided between the first and second flange portions. The coil is wound on a second groove defined between the second and third flange portions. An end portion of the coil is connected and fixed to a lead wire (connected to a detection circuit unit) in a first groove defined between the first and third flange portions. The diameter of one of the flange portions of the detection coil unit can he larger than the diameter of the other flange portions to prevent improper assembly of the detection coil unit.

Abstract: A plural number of grooves, circumferentially spaced, are formed in a surrounded portion of a first rotary shaft made of magnetic material. A thin tubular member made of conductive and nonmagnetic material, is integrally coupled with a second rotary shaft in the rotation direction, while surrounding the surrounded portion of the first rotary shaft. A plural number of windows are formed in the tubular member. The windows are arrayed so as to partially overlap with the grooves, respectively. An overlapping area of the window and the groove associated therewith is varied in accordance with a relative turn of the tubular member to the surrounded portion. The portions of the tubular member having the windows formed therein are surrounded by coils. The self-induction electromotive force of each of the coils is measured. A torque is detected on the basis of the self-induction electromotive forces measured.

Abstract: Rotaton of a steering wheel is transmitted to a steering ratio changing mechanism which displaces an output displacement member according to the steering wheel turning angle to obtain a desired steering ratio. A displacment transmission member transmits the displacement of the output displacement member to a valve member of a hydraulic switching valve and a wheel turning rod is displaced under the force of a hydraulic power cylinder in response to displacement of the valve member.