Patents Assigned to NSK Steering Systems Co., Ltd
  • Patent number: 7413051
    Abstract: Since a nut 45 is provided with paths for connecting rolling paths 23b, 45f and circulating paths 45c, that is, return paths 45d at end caps 45b, 45b attached to both ends of a main body 45a, a receiving portion for receiving power transmitted from an electric motor 35, that is, a driven gear portions 45e is provided at a center of an outer peripheral face on outer sides in a radius direction of the rolling paths and therefore, when power is transmitted from the electric motor 35 to the driven gear portion 45e, smooth operation can be carried out by restraining the nut 45 from being twisted.
    Type: Grant
    Filed: March 21, 2005
    Date of Patent: August 19, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Jun Okada
  • Patent number: 7404768
    Abstract: A telescopic shaft for vehicle steering has first and second torque transferring members. The first torque transferring member is interposed, with an elastic body in between, between axial grooves formed in an outer peripheral surface of a male shaft and an inner peripheral surface of a female shaft. The second torque transferring member is interposed between other axial grooves formed in the outer peripheral surface of the male shaft and in the inner peripheral surface of the female shaft. The elastic body has transferring-member-side contact portions contacting the first torque transferring member, shaft-side contact portions contacting groove surfaces of the axial groove of the male shaft or the female shaft, and a biasing portion for elastically urging the transferring-member-side contact portions and the shaft-side contact portions away from each other. Rigidity of the transferring-member-side contact portions is different from that of the shaft-side contact portions.
    Type: Grant
    Filed: June 11, 2004
    Date of Patent: July 29, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Yasuhisa Yamada
  • Patent number: 7401813
    Abstract: In a steering apparatus for a vehicle in which an inner column is supported to be movable in the axial direction by an outer jacket supported by a body-side bracket and a steering shaft is fixed to an adjustment position by clamping the inner column by the use of telescopic clamping means through the outer jacket, the outer jacket is provided with a slit entirely along the axial direction thereof.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: July 22, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Naoki Sawada, Yuichi Tomaru
  • Patent number: 7397210
    Abstract: In the present invention, only an abnormality of detection of a rotating direction of a motor is detected and therefore, with simple processing and by using a table for judging the abnormality of the detection of a rotating direction of a motor and the rotating direction of the motor, the abnormality of the detection of a rotating direction and the rotating direction of the motor are judged at one time.
    Type: Grant
    Filed: October 6, 2004
    Date of Patent: July 8, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Kenji Arai, Yuho Aoki
  • Patent number: 7394214
    Abstract: In order to solve a problem that a motor generates a noise so as to deteriorate an environment in a vehicle if a field weakening control is executed to the motor of a electric power steering apparatus, in the case that a vehicle speed is high, the same field weakening control as the conventional one is applied to the motor because a noise generated due to a friction between a tire and a road surface and a wind noise of a vehicle body are large, and in the case that the vehicle speed is low, the field weakening control is weakly applied in comparison with the conventional one because the noise generated by the motor is felt relatively largely. Accordingly, the field weakening control can be executed in response to the vehicle speed in such a manner as to make the motor noise smaller.
    Type: Grant
    Filed: November 11, 2004
    Date of Patent: July 1, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Shuji Endo, Yuho Aoki
  • Patent number: 7389851
    Abstract: An electric power steering apparatus controlling an operation of an electric motor by a control unit based on a torque signal from a torque sensor and executing a steering assist of a steering shaft via a reduction mechanism. The control unit includes a power supply voltage detector for detecting a power supply voltage signal of an in-vehicle power supply, and an output inhibitor for inhibiting an output in multiple stages based on a power supply voltage detected by the detector. A maximum driving current of the motor is limited when the voltage is decreased by the inhibitor to reach a first reference value (V1), a motor control output gain is decreased when the voltage reaches a second reference value (V2), and the output is turned off when the voltage reaches a third reference value (V3).
    Type: Grant
    Filed: June 3, 2005
    Date of Patent: June 24, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Yasuhiko Miyaura
  • Patent number: 7382295
    Abstract: Since an abnormality is judged by executing a square calculating process with respect to sin ? and cos ? for detecting an abnormality in an angular resolver, a processing time is elongated, and a burden to a CPU is great. Since the invention prepares a map which can judge whether the combination of sin ? and cos ? is normal or abnormal, and judges by mapping the combination of the detected sin ? and cos ?, a process can be easily executed, a processing speed is high, and a burden to the CPU can be reduced. Further, an assist can be maintained by controlling a motor by a rectangular wave current by detecting a rotation angle signal at low resolution level, such as Hall sensors arranged around the motor.
    Type: Grant
    Filed: November 1, 2004
    Date of Patent: June 3, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Tetsuro Otsuka, Atsushi Horikoshi, Yuho Aoki
  • Patent number: 7382105
    Abstract: In a motor driving device where a motor having a winding wire with small inductance value is driven by a digital control means comprised of control means including a current command value calculating means, a current control means and a PWM control means whose sampling periods are different from each other, when discrete signals sampled by the respective control means are zero-order-held, a motor current includes a lot of higher harmonic waves due to a quantization error, thereby increasing a motor noise. When an n-th-order hold means is provided between the respective control means with different sampling periods, the quantization error can be reduced remarkably, and thus the higher harmonic wave components included in the motor current are reduced, thereby greatly reducing the motor noise.
    Type: Grant
    Filed: December 2, 2004
    Date of Patent: June 3, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Shuji Endo, Masahide Saito, Kenji Mori, Lilit Kovudhikulrungsri, Toru Sakaguchi
  • Patent number: 7367588
    Abstract: A steering column device comprises a bracket of the column body having mounting flanges with a cut-away groove opening in the backward direction of car body, a collar having a flange part and a cylindrical part, an elastically deformable ring which the cylindrical part of the collar can be inserted in, and a bolt for compressing the ring, putting the mounting flange of the column body between the ring and the flange part, thereby the steering column is mounted on the car body but allowed to be detached from the car body in the secondary collision.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: May 6, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Jun Yamada
  • Patent number: 7364197
    Abstract: A steering column apparatus, includes: a fixed column member having a vehicle body attachment portion to be attached to a vehicle body; a column head supported by the fixed column member movably in a direction of a center shaft of the fixed column member; a wheel shaft, rotatably supported by the column head, for fixing a steering wheel to an end thereof; a column clamp, provided in the column head, for putting the column head into a state in which the column head is clamped to or unclamped from the fixed column member; an operation lever having a rocking shaft in the column head; and a mechanical transmission apparatus for transmitting a rocking motion of the operation lever to the column clamp.
    Type: Grant
    Filed: October 6, 2004
    Date of Patent: April 29, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Masaki Nishioka, Naoki Sawada
  • Patent number: 7360467
    Abstract: A torsion coil spring 30 applies an elastic force to a worm shaft 29 in a direction towards a worm wheel, via a pre-load pad 70. The pre-load pad 70 restricts displacement in relation to the widthwise direction, by one side face portion of a holder 61 fixed to a gear housing 22. Due to the elastic deformation of the pre-load pad 70 itself based on the elastic force of the torsion coil spring 30, the side face of the pre-load pad 70 is abutted against the one side face portion of the holder 61, so that a gap between the pre-load pad 70 and the one side face portion is minimized. As a result, the occurrence of a teeth fitting noise in the worm reduction gear 16 is suppressed.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: April 22, 2008
    Assignees: NSK, Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Toru Segawa, Kazuo Chikaraishi
  • Patent number: 7357216
    Abstract: A ball bearing 34 serving as a support reference for a pinion shaft 2 is located directly under a worm wheel 51. Thus, even when a temperature change occurs around the electric power steering apparatus, the engagement position between the worm wheel 51 and the worm 53 shifts only slightly in the axial direction of the pinion shaft 2. Furthermore, a bearing hole 47 into which an outer race of a lower needle bearing 36 is pressed and a bearing hole 45 into which an outer race of an upper ball bearing 34 is pressed are formed in a common lower gear box 41, and can be fabricated by through processing using a boring tool from the bearing hole 45 side.
    Type: Grant
    Filed: March 15, 2005
    Date of Patent: April 15, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Nobuhiro Ishii, Hisao Ubukata
  • Patent number: 7354069
    Abstract: A steering apparatus includes: an inner column which rotatably supports a steering shaft; an outer jacket which incorporates the inner column shiftably in an axial direction, at least a portion of the outer jacket being cylindrical; and an urging member for urging the inner column. The outer jacket includes: a pressed portion which extends in a direction leaving an axial line from the outer periphery of the outer jacket and is urged by the urging member, a slit which extends in the axial direction over the pressed portion from the end of the outer jacket, and a notch which leads to the slit extending over the pressed portion. The notch has a tapered shape which enlarges toward an opening side when the outer jacket is viewed in an urging direction of the urging member.
    Type: Grant
    Filed: November 4, 2004
    Date of Patent: April 8, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Jun Yamada
  • Patent number: 7345442
    Abstract: Distortions of motor voltage and current and a torque ripple of the motor are generated by dead band compensation for preventing an arm short circuit of an inverter, and a feeling of physical disorder is given in a handle operation. Therefore, the distortions of the motor voltage and current and the torque ripple of the motor are improved by using the dead band compensation for estimating the voltage distortion on the basis of a model current generated from a current command value such that no feeling of physical disorder is given in the handle operation of an electric power steering apparatus.
    Type: Grant
    Filed: September 1, 2004
    Date of Patent: March 18, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: CaoMinh Ta, Hiroaki Takase, Hideyuki Kobayashi
  • Patent number: 7343254
    Abstract: In a resolver digital converter comprising a resolver, a resolver digital conversion part, and an excitation signal generation part, the resolver digital converter for inputting an excitation signal generated in the excitation signal generation part to the resolver and inputting resolver signals outputted from the resolver to the resolver digital conversion part, a locus in which amplitude of a sine component signal among the resolver signals sin(?), cos(?) outputted from the resolver is plotted as the ordinate axis and amplitude of a cosine component signal is plotted as the abscissa axis is approximated by a polygon and when the locus matches with sides of the approximated polygon, it is determined that the resolver is in a normal state and when the locus does not match, it is determined that the resolver is in a failure state.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: March 11, 2008
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventors: Tetsuro Otsuka, Atsushi Horikoshi, Nobuyasu Kanekawa, Shoji Sasaki
  • Publication number: 20070251758
    Abstract: A torsion coil spring 30 applies an elastic force to a worm shaft 29 in a direction towards a worm wheel, via a pre-load pad 70. The pre-load pad 70 restricts displacement in relation to the widthwise direction, by one side face portion of a holder 61 fixed to a gear housing 22. Due to the elastic deformation of the pre-load pad 70 itself based on the elastic force of the torsion coil spring 30, the side face of the pre-load pad 70 is abutted against the one side face portion of the holder 61, so that a gap between the pre-load pad 70 and the one side face portion is minimized. As a result, the occurrence of a teeth fitting noise in the worm reduction gear 16 is suppressed.
    Type: Application
    Filed: May 10, 2007
    Publication date: November 1, 2007
    Applicants: NSK LTD., NSK Steering Systems Co., Ltd.
    Inventors: Toru Segawa, Kazuo Chikaraishi
  • Publication number: 20070132414
    Abstract: In the present invention, only an abnormality of detection of a rotating direction of a motor is detected and therefore, with simple processing and by using a table for judging the abnormality of the detection of a rotating direction of a motor and the rotating direction of the motor, the abnormality of the detection of a rotating direction and the rotating direction of the motor are judged at one time.
    Type: Application
    Filed: October 6, 2004
    Publication date: June 14, 2007
    Applicants: NSK LTD., NSK STEERING SYSTEMS CO., LTD.
    Inventors: Kenji Arai, Yuho Aoki
  • Patent number: 7213484
    Abstract: Disclosed here is a steering column apparatus that enables a single operation lever provided apart from the steering wheel and to be used for clamping/unclamping each of the telescopic mechanism and the tilting mechanism independently, as well as for keeping at least one of the telescopic mechanism and the tilting mechanism unclamped after it is unclamped even after the driver takes his/her hand off the operation lever. This makes it possible for the driver to use both hands to adjust at least either the position in the front-rear direction or tilting angle of the steering wheel.
    Type: Grant
    Filed: February 10, 2004
    Date of Patent: May 8, 2007
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Naoki Sawada
  • Publication number: 20070083308
    Abstract: The present invention provides a steering angle estimating apparatus for vehicle that can accurately determine a steady state at all the steering angles, and can estimate the steering angle as much as possible even in a non-steady state. In the steering angle estimating apparatus for vehicle that has wheel rotational velocity sensors for four wheels, respectively, and estimates the steering angle of the vehicle based on wheel rotational velocities from the wheel rotational velocity sensors, relationships in the wheel rotational velocities between respective combinations of two wheels of the front and rear wheels on right and left sides are compared so that slip of the four wheels is detected.
    Type: Application
    Filed: September 14, 2004
    Publication date: April 12, 2007
    Applicants: NSK LTD, NSK STEERING SYSTEMS CO., LTD.
    Inventor: Takeshi Hara
  • Patent number: 7202621
    Abstract: A power steering control device includes a torque sensor that detects a steering torque and outputs a torque signal having a torque neutral voltage is determined based on a predetermined reference voltage, a reference-voltage generator unit that generates the reference voltage, an A/D converter unit that A/D converts the torque signal and the reference voltage, a calculator unit that calculates a steering assist torque based on the A/D converted torque signal, a current controller unit that supplies a driving current in accordance with the assist torque to a steering assist motor, a reference-voltage generator unit that generates the reference voltage and outputs the reference voltage to the A/D converter unit and a fault diagnosis unit that monitors the A/D converted reference voltage and performs a predetermined fault diagnosis process.
    Type: Grant
    Filed: May 11, 2005
    Date of Patent: April 10, 2007
    Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.
    Inventor: Mikihiko Tsunoda