Patents Assigned to NSK Ltd.
  • Patent number: 7322607
    Abstract: A telescopic shaft for steering of a vehicle is assembled in a steering shaft and includes a male shaft and a female shaft that are so fitted as not to be rotatable but to be slidable. Rolling members are fitted through an elastic body for pre-load between at least a pair of axially-extending grooves formed in an outer peripheral surface of the male shaft and in an inner peripheral surface of the female shaft. A slide member is fitted in between at least another pair of axially-extending grooves formed in the outer peripheral surface of the male shaft and in the inner peripheral surface of the female shaft. When a steering toque is equal to or smaller than a predetermined level, the elastic body for the pre-load exhibits a low rigidity characteristic as the elastic body performs pre-load action. When the steering torque is equal to or larger than the predetermined level, the slide member exhibits a high rigidity characteristic as the slide member engages with the pair of axially extending grooves.
    Type: Grant
    Filed: June 10, 2003
    Date of Patent: January 29, 2008
    Assignee: NSK Ltd.
    Inventors: Yasuhisa Yamada, Akihiro Shoda, Atsushi Ozawa, Kinji Yukawa, Takatsugu Yamada
  • Patent number: 7322610
    Abstract: In a manufacturing method of a steering column apparatus for a car in which a column-side bracket attached to a steering column is brought into pressure contact with a body-side bracket attached onto the body of the car to be retained, the body-side bracket or the column-side bracket is comprised of a plurality of divided components in advance, and these plurality of divided components are connected to each other by caulking at the time of assembling, so as to assemble the body-side bracket or the column-side bracket.
    Type: Grant
    Filed: May 13, 2003
    Date of Patent: January 29, 2008
    Assignee: NSK Ltd.
    Inventors: Ryuuichi Ishida, Toshimichi Takano, Masaki Tomaru
  • Patent number: 7322608
    Abstract: A steering column apparatus comprises a steering shaft having its rear end to which a steering wheel is secured, a steering column supporting rotatably the steering shaft and adjustable of its length in axial directions together the steering shaft, and telescopic position fixing means for fixing the steering column to a desired length. The steering column is constructed of an outer column fixed on a car body side and an inner column slidably fitted in the outer column. The telescopic position fixing means is constructed of a lock housing formed on the outer column, first and second press blocks slidably held by the lock housing and moving forwards and backwards in a way that embraces an outer peripheral surface of the inner column, and presses block driving means for bringing the first and second press-blocks into a press-contact with the inner column.
    Type: Grant
    Filed: December 4, 2003
    Date of Patent: January 29, 2008
    Assignee: NSK Ltd.
    Inventors: Kou Yamamoto, Daijiro Yamasaki
  • Publication number: 20080018277
    Abstract: The invention provides a drive control device for the motor as well as an electric power steering apparatus using the motor and the drive control device. Respective phase current command values are calculated on the basis of vector control. Pseudo-vector control for controlling respective phases separately is used as current feedback control.
    Type: Application
    Filed: September 25, 2007
    Publication date: January 24, 2008
    Applicant: NSK Ltd.
    Inventors: CaoMinh TA, Shuji Endo
  • Publication number: 20080018280
    Abstract: There is provided a control device of an electric power steering apparatus controlling a motor for applying steering assist torque to a steering mechanism through a driving part. The control device includes a control computation part that computes a current command value and controls the motor based on the computed current command value, a first voltage reduction monitoring part that generates a reset signal for stopping the control computation part at the time of a low voltage and a second voltage reduction monitoring part that holds reduction extent information about a power source voltage. The first and second voltage reduction monitoring parts cooperate together to monitor a reduction in the power source voltage of the control computation part.
    Type: Application
    Filed: July 10, 2007
    Publication date: January 24, 2008
    Applicant: NSK LTD.
    Inventor: Masahiro MAEDA
  • Publication number: 20080021614
    Abstract: A computed SAT value SATa is computed, and an estimated SAT value SATb is estimated from lateral force. A grip loss level “g” is computed from difference between the computed self aligning torque value SATA and the estimated SAT value SATb. Torque correction value ?T which becomes greater with an increase in grip loss level “g” and an increase in angular speed ? is set in accordance with the grip loss level “g” and the angular speed ? of an electric motor 12 serving as corresponding steering angular speed. The corresponding torque correction value ?T is subtracted from the current command value Itv responsive to the steering torque T and the vehicle speed V, thereby correcting the current command value Itv. The thus-corrected current command value Itv is taken as a steering assist command value Im, and the electric motor 12 is driven based on the steering assist command value.
    Type: Application
    Filed: July 19, 2007
    Publication date: January 24, 2008
    Applicant: NSK LTD.
    Inventors: Shuji ENDO, Yuho AOKI, Apiwat REUNGWETWATTANA
  • Publication number: 20080018278
    Abstract: The invention provides a motor for a brushless DC motor, which has small torque ripple even if a trapezoidal wave current is supplied and has a small size and reduced motor noise. Respective phase current command values are calculated on the basis of vector control. Pseudo-vector control for controlling respective phases separately is used as current feedback control.
    Type: Application
    Filed: September 25, 2007
    Publication date: January 24, 2008
    Applicant: NSK Ltd.
    Inventors: CaoMinh TA, Shuji Endo
  • Patent number: 7320257
    Abstract: Revolution speeds nca, nib of rolling elements 9a, 9b are sensed by a pair of revolution speed sensors 21a, 21b. Also, a rotational speed ni of a hub 2 is sensed by a rotational speed sensor 15b. A sum “nca+ncb” or a difference “nca?nib” the revolution speeds of rolling elements 9a, 9b in double rows is calculated based on sensed signals of the revolution speed sensors 21a, 21b, and then a ratio “nca+nib/ni” or “nca?ncb/ni” of this sum or difference to the rotational speed ni is calculated. Then, the radial load or the an axial load is calculated based on the ratio “nca+ncb/ni” or “ca?nib/ni”.
    Type: Grant
    Filed: May 6, 2004
    Date of Patent: January 22, 2008
    Assignee: NSK Ltd.
    Inventors: Takeshi Takizawa, Tomoyuki Yanagisawa, Koichiro Ono, Ikunori Sakatani
  • Patent number: 7320256
    Abstract: Revolution speeds of rolling elements in respective rows are sensed, and then the axial load or the radial load is derived based on the revolution speeds. In case the acting directions of these loads are displaced, the contact angles of the rolling elements in respective rows are differentiated in response to this displacement, or values of influence coefficients used to detect respective loads are changed based on the revolution speeds.
    Type: Grant
    Filed: August 26, 2004
    Date of Patent: January 22, 2008
    Assignee: NSK Ltd.
    Inventor: Koichiro Ono
  • Publication number: 20080010830
    Abstract: A method of manufacturing a toothed power transmission member having an oil reservoir according to the present invention includes steps of forming primitive concave portion, which form a basis for the oil reservoir, on a surface of a toothed power transmission member work, and forming a tooth surface by processing the toothed power transmission member work such that a trace of the primitive concave portion is left on the toothed power transmission member thereby to form a toothed power transmission member. The trace of the primitive concave portion, which is formed in the step of forming a tooth surface and left on the toothed power transmission member, serves as the oil reservoir.
    Type: Application
    Filed: November 29, 2005
    Publication date: January 17, 2008
    Applicant: NSK LTD.
    Inventors: Shinji Okada, Yasushi Watanabe, Naoki Hara, Seiichi Moriyama, Hideki Hidaka
  • Publication number: 20080009387
    Abstract: The support beam 34 having the cylindrical convex surface 33 is provided at the intermediate portion of the trunnion 9b. The recess 38 of the partial cylindrical surface formed on the outside of the outer ring 37 on the thrust ball bearing 36 supporting the power rollers 8b and the cylindrical convex surface 33 of the support beam are engaged. The outer ring and the power rollers 8b are supported swingably in the axial direction of the input and output discs in respect to the trunnions 9b.
    Type: Application
    Filed: June 4, 2007
    Publication date: January 10, 2008
    Applicant: NSK LTD.
    Inventors: Hiroki Nishii, Eiji Inoue, Jorg Mockel
  • Publication number: 20080010039
    Abstract: An object of the invention is to provide an anomaly diagnosis apparatus of a machine installation for eliminating the need for the user to have a dedicated analytical instrument or a skill required for anomaly diagnosis of a sliding member and enabling the user to easily make an anomaly diagnosis request with a small burden and get the diagnosis result promptly. In the invention, an anomaly diagnosis apparatus for analyzing sound or vibration data produced by a machine installation and diagnosing the presence or absence of an anomaly in a sliding member in the machine installation is made up of a diagnosis processing server (1) and a user information processing terminal (3) which are connected through a network (2).
    Type: Application
    Filed: August 29, 2007
    Publication date: January 10, 2008
    Applicant: NSK Ltd
    Inventors: Takanori Miyasaka, Hirotoshi Aramaki, Yasushi Mutoh, Shinichiro Asaeda
  • Publication number: 20080000316
    Abstract: This invention provides a telescopic shaft in which a backlash or a sliding resistance in a rotational direction is maintained to a predetermined value even when there are fabrication errors in a male shaft and a female shaft, and a preload is not reduced even when a sleeve is worn by a friction force in sliding, and a steering apparatus having the telescopic shaft. An inclined sleeve portion 712 is pressed by an elastic deformation of an urge sleeve portion 713, so that there is not backlash between a male shaft 12B and a female shaft 12A and a predetermined preload is applied. Although an outer periphery of the inclined sleeve portion 712 is worn by a friction in sliding, the inclined sleeve portion 712 is further pressed by an elastic force of the urge sleeve portion 713 by an amount of wearing the outer periphery of the inclined sleeve portion 712. Thus, a predetermined urge force is always operated to the inclined sleeve portion 71.
    Type: Application
    Filed: June 27, 2007
    Publication date: January 3, 2008
    Applicant: NSK LTD.
    Inventor: Yoshifumi KUROKAWA
  • Publication number: 20080004773
    Abstract: A control device for an electric power steering apparatus has a motor which applies a steering assist force and a driving control device which drives the motor, the driving control device has a gate driving circuit which drives a motor driving bridge circuit based on a command from a computer, the power supply portion of the gate driving circuit has a voltage limit unit, and there is provided with a function of driving the lower side driving elements of the motor driving bridge circuit when the voltage limit unit detects the abnormally high voltage of the power supply voltage.
    Type: Application
    Filed: June 21, 2007
    Publication date: January 3, 2008
    Applicant: NSK LTD.
    Inventor: Masahiro MAEDA
  • Publication number: 20070297705
    Abstract: A thin-wall bearing, comprising a retainer (4) formed in a divided type having a plurality of resin plate-like members (5), (5), . . . curved along an inner ring (1) and an outer ring (2). The retainer (4) comprises pockets (6) opening to the axial end part thereof and rollingly holding balls (3). Slit-like through holes (14) extending in the axial direction and opening to the axial end part where the opening parts (7) of the pockets (6) are positioned are formed at the center parts of pillars (10) between the pockets (6) and (6) adjacent to each other. As a result, the thin-wall bearing can have excellent lubricity.
    Type: Application
    Filed: January 31, 2006
    Publication date: December 27, 2007
    Applicant: NSK Ltd.
    Inventors: Masachi Hosoya, Toshiaki Yamaguchi, Tsuyoshi Saitou, Hiroyuki Itou, Yasushi Tomizuka, Toyohisa Yamamoto
  • Publication number: 20070297901
    Abstract: A structure of a water pump is provided without increasing the cost thereof, or without enlarging the size to improve the durability of the water pump. A seal apparatus having a seal ring 13 and a slinger 14 in combination to prevent foreign matter from progressing into the rolling bearing 6a. The amount of compression 6 of the second seal lip 23, which occurs when the tip edge of the second seal lip 23 of the seal ring 13 comes in contact with the outer peripheral surface of the outer-diameter-side cylindrical section 26 that is formed at the outer peripheral edge of the slinger 14, is at least 1/10 and up to 7/10 the height of the second seal lip 23 in the free state. In addition, the roughness of a portion of the outer peripheral surface of the outer-diameter-side cylindrical section 26 which the tip edge of the second seal lip 23 comes in sliding contact with is from 0.2 ?m to 2.0 ?m in the arithmetic mean Ra, or is from 0.8 ?m to 8.0 ?m in the maximum height Ry.
    Type: Application
    Filed: August 27, 2007
    Publication date: December 27, 2007
    Applicant: NSK LTD.
    Inventor: Masamichi IKETANI
  • Publication number: 20070296375
    Abstract: This invention provides a control method for a motor that calculates a voltage command value based on a difference between a current command value and a current detected value and controls a PWM based on the voltage command value. The control method includes steps of: detecting a failure or an undetectable state of a current detecting system; obtaining a current estimated value of a failure phase or an undetectable state phase by using the current detected value except the failure phase or the undetectable state phase when the failure or the undetectable state is detected; and continuously controlling the motor by using the current estimated value.
    Type: Application
    Filed: June 8, 2007
    Publication date: December 27, 2007
    Applicant: NSK LTD.
    Inventors: Toru SAKAGUCHI, Shuji ENDO, Lilit KOVUDHIKULRUNGSRI
  • Patent number: 7311447
    Abstract: A roller bearing for rotatably supporting a rotating shaft of an internal combustion engine between a main body and a cap of the internal combustion engine. The roller bearing including: a plurality of rollers; a retainer which is cirumferentially splittable and supports the plurality of rollers; and an outer race which is cirumferentially splittable and forms a raceway surface for the plurality of rollers. The retainer is split into a plurality of retaining members. The outer race is split into a plurality of race plates. At least one of the race plates is provided with one of a projection and a cavity to be engaged with one of the main body and the cap to restrict a relative movement between the one of the race plates and the one of the cylinder head and the cap.
    Type: Grant
    Filed: August 31, 2004
    Date of Patent: December 25, 2007
    Assignee: NSK Ltd.
    Inventors: Noriyuki Takeo, Satoshi Kadokawa, Akira Takahashi
  • Patent number: 7311482
    Abstract: An object of the invention is to provide a spindle apparatus which facilitates assembling and removing operations at the time of maintenance and which is low cost. In the invention, the diameter becomes smaller in the order of an inner peripheral diameter of an outer cylinder (3), an inside diameter of a stator (4), and an outside diameter of a bearing sleeve (11); a sub-assembly (2) made up of a front housing (8), a rotating shaft (6), and the bearing sleeve (11) is withdrawable from the outer cylinder (3); and the diameter of a rotating part in an arbitrary section located rearwardly of the bearing sleeve (11) is made smaller than a minimum diameter of a non-rotating part between a rear end of the bearing sleeve (11) and the section.
    Type: Grant
    Filed: March 31, 2004
    Date of Patent: December 25, 2007
    Assignee: NSK Ltd.
    Inventors: Sumio Sugita, Mitsuho Aoki, Yoshifumi Inagaki, Yasushi Morita
  • Patent number: 7311333
    Abstract: An impact absorbing type steering column apparatus for an automotive vehicle is capable of adjusting a steering position and, when a secondary collision happens, absorbs impact energy thereof by moving a steering column supported through a bracket on a car body towards the front of the vehicle. The bracket includes a restricting portion for restricting a steering position adjusting range of the steering column. The restricting portion allows, upon the secondary collision, the steering column to move beyond the steering position adjusting range.
    Type: Grant
    Filed: July 9, 2003
    Date of Patent: December 25, 2007
    Assignee: NSK, Ltd.
    Inventors: Kenji Sato, Naoki Sawada