Patents by Inventor Isamu Chikuma
Isamu Chikuma has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6711965Abstract: An electric tilt and/or telescopic steering column apparatus comprises a steering shaft having a steering wheel mounted on a rear end thereof, a steering column for rotatably supporting the steering shaft, an electric actuator for adjusting the tilt and/or telescopic position of the steering shaft by driving this steering column, and position detecting means for detecting the position of the steering shaft in a non-contact manner.Type: GrantFiled: April 29, 2002Date of Patent: March 30, 2004Assignee: NSK Ltd.Inventors: Masaki Tomaru, Isamu Chikuma, Sakae Matsumoto, Kazuya Fukuda, Takahiro Saito
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Publication number: 20020124677Abstract: An electric tilt and/or telescopic steering column apparatus comprises a steering shaft having a steering wheel mounted on a rear end thereof, a steering column for rotatably supporting the steering shaft, an electric actuator for adjusting the tilt and/or telescopic position of the steering shaft by driving this steering column, and position detecting means for detecting the position of the steering shaft in a non-contact manner.Type: ApplicationFiled: April 29, 2002Publication date: September 12, 2002Applicant: NSK Ltd.Inventors: Masaki Tomaru, Isamu Chikuma, Sakae Matsumoto, Kazuya Fukuda, Takahiro Saito
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Patent number: 6237955Abstract: A shock absorbing steering column apparatus comprise a steering column member admitting an insertion of a steering shaft, and a shock absorbing member for permitting the steering column member to displace in an axial direction while being plastically deformed by an impact load applied in the axial direction of the steering column member. The steering column member and the shock absorbing member are integrally formed of a non-ferrous metal.Type: GrantFiled: September 21, 1999Date of Patent: May 29, 2001Assignee: NSK Ltd.Inventors: Kenji Sato, Isamu Chikuma, Sakae Matsumoto
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Patent number: 6237954Abstract: An apparatus for supporting a steering column has a cross member spanned over two right-and-left walls of a car body at a portion just anterior to a driver's seat, a support bracket integrally fixedly connected to a portion, aligned with the driver's seat, of an intermediate portion of the cross member, a supported bracket fixedly connected to an intermediate portion of the steering column, and a connecting member for connecting the support bracket and the supported bracket to each other with no intermediary of other brackets.Type: GrantFiled: July 28, 1999Date of Patent: May 29, 2001Assignee: NSK Ltd.Inventors: Kenji Sato, Isamu Chikuma, Sakae Matsumoto, Kiyoharu Higashino
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Patent number: 5732790Abstract: In order to provide an electric power steering apparatus which can be made compact as well as reduced in cost and can be improved in reliability, a control circuit and a drive circuit are provided on a deformable flexible circuit substrate. The circuit substrate is provided on the housing of a reduction gear mechanism while being deformed so as to cover a portion of the outer surface of the housing along the shape of the outer surface.Type: GrantFiled: November 27, 1995Date of Patent: March 31, 1998Assignee: NSK Ltd.Inventors: Shuji Endo, Hiroyuki Kano, Hideaki Kawada, Yasuhiko Miyaura, Isamu Chikuma, Hiroshi Eda, Shozo Sekiya, Nobuyasu Ando, Kenichi Hayakawa
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Patent number: 5685390Abstract: An electrically-operated power steering apparatus comprises a steering shaft, a rack shaft capable of linear movement for turning a steering running wheel a, rack-pinion gear for coupling the steering shaft with the rack shaft, and a ball screw mechanism including a screw groove formed on the rack shaft, a rotary ball screw nut fitted on the rack shaft, and plural balls positioned in a rolling path. The plural balls are comprised of bulbs of a larger diameter and balls of a smaller diameter, which are alternately arranged, and the smaller diameter is within a defined range.Type: GrantFiled: March 10, 1995Date of Patent: November 11, 1997Assignee: NSK, Ltd.Inventors: Isamu Chikuma, Kenji Someya, Hiroshi Eda
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Patent number: 5508921Abstract: A four-wheel steering apparatus comprises a front wheel steering angle sensor for detecting the steering angles given to the front wheels, a vehicle speed sensor for detecting vehicle speeds, a rear wheel output shaft for giving steering angles to the rear wheels by being displaced it in the axial direction, a centering spring having the resiliency enabling the rear wheel output shaft to be returned to the neutral position, an electric motor for causing the rear wheel output shaft to be displaced in the axial direction against the resiliency of the centering spring, and a controller for controlling the energizing of the electric motor on the basis of the signals from the front wheel steering sensor and vehicle speed sensor, the controller adjusting the output torque of the electric motor on the basis of the signals from the front wheel steering sensor and vehicle speed sensor to control the rear wheel output shaft to be displaced for a desired amount by open loop control.Type: GrantFiled: June 7, 1995Date of Patent: April 16, 1996Assignee: NSK, Ltd.Inventors: Isamu Chikuma, Hiroshi Eda, Hiroyuki Kanou, Nobuyasu Ando, Kaoru Kiyono
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Patent number: 5482127Abstract: A power transmission device, having a frictional face and a pressure member pressed to the frictional face, is provided between the rotary shaft of a motor and a reducing mechanism of an electric power steering device, so that the power transmission is achieved utilizing a frictional force generated between the frictional face and the pressure member, before the output torque of the motor is amplified by the reducing mechanism. Consequently the power transmission device can be made simple and compact in configuration, as it is not necessary to increase the pressing force of the pressure member nor to increase the area of the frictional face.Type: GrantFiled: June 1, 1994Date of Patent: January 9, 1996Assignee: NSK Ltd.Inventors: Hiroshi Eda, Hironobu Shiono, Isamu Chikuma
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Patent number: 5454438Abstract: In order to provide an electric power steering system of small size whose output shaft has little play, a pressure member of the electric-driven power steering system compresses a duplex bearing, more specifically, presses two bearing components of the duplex bearing against each other. As a result, the play which the output shaft has in each bearing is removed.Type: GrantFiled: March 31, 1994Date of Patent: October 3, 1995Assignee: NSK Ltd.Inventor: Isamu Chikuma
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Patent number: 5445238Abstract: An electric power steering apparatus can maintain suitable backlash in a temperature changing atmosphere even if a gear consisting of a metallic cylindrical core portion and a toothed resin outer ring portion. The thickness of the resin outer ring portion is suitably determined by the coefficients of linear thermal expansion of a driving gear, a driven gear, a housing, the addendum of the driven gear and the center distance between the driving gear and the driven gear. Even if the temperature of the atmosphere changes, the positional relation between the gears is unchanged. Thus, the backlash is substantially unaltered.Type: GrantFiled: January 25, 1995Date of Patent: August 29, 1995Assignee: NSK Ltd.Inventors: Isamu Chikuma, Toshiyuki Iwano
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Patent number: 5445237Abstract: An electric power steering apparatus having a compact and inexpensive backlash mechanism is provided by arranging its structure to easily adjust the backlash of the bevel gear mechanism, and at the same time, to pre-press the bearings so that the movement of the shaft in the axial direction can be regulated. The rotational shaft having a small gear coupled thereto which constitutes a bevel gear mechanism on one side is rotatively supported by a housing, but disabled to shift in the axial direction. The large gear which constitutes the bevel gear mechanism on the other side is coupled to the output shaft of a steering system so that it can shift in the rotational direction and axial direction together with the shaft. The output shaft is rotatively supported by bearings with respect to the housing with a movable sleeve which abuts upon the outer ring of the bearing.Type: GrantFiled: December 23, 1994Date of Patent: August 29, 1995Assignee: NSK Ltd.Inventors: Hiroshi Eda, Kenji Someya, Isamu Chikuma
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Patent number: 5295550Abstract: A four-wheel steering apparatus operates such that only when the vehicle velocity is lower than a predetermined value, is the provision of the steering angle to the rear wheels electrically controlled by the steering angle sensor for the front wheels and vehicle velocity sensor while at a high-speed traveling, the provision of the steering angle to the rear wheels is performed by the compliance steering mechanism. Hence the control and stability are improved as compared with the case where the steering angle is given to the rear wheels electrically even at a high-speed traveling.Type: GrantFiled: September 4, 1991Date of Patent: March 22, 1994Assignee: NSK Ltd.Inventor: Isamu Chikuma
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Patent number: 5248009Abstract: A vehicle rear wheels steering apparatus is provided with a guide member having a guideway capable of freely tilting toward the axis of the rod member. Therefore, when the rod member rotates around the axis, an operating member provided on the outside of the rod member rotates around the rod member axis along the guideway to steer the rear wheels by an amount corresponding to an amount of rotation of the rod member and an amount of tilting of the guideway.Type: GrantFiled: September 5, 1991Date of Patent: September 28, 1993Assignees: NSK Ltd., Mazda Motor CorporationInventors: Shin Takehara, Hiroshi Ohmura, Ryuya Akita, Isamu Chikuma, Hiroyuki Ito, Hiroshi Eda
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Patent number: 5236057Abstract: A rear wheel steering apparatus for a vehicle, comprises a hydraulic cylinder for displacing a steering rod connected to left and right rear wheels axially, a centering spring for biasing the steering rod toward a neutral position, and a centering spring cancelling mechanism for preventing a biasing force of the centering spring from acting on the steering rod. A partition wall of the hydraulic cylinder defines an oil chamber in the cylinder and is formed as a cup shape having a central concave portion which constitutes a pressure chamber of the centering spring cancelling mechanism.Type: GrantFiled: September 4, 1991Date of Patent: August 17, 1993Assignees: NSK Ltd., Mazda Motor CorporationInventors: Shin Takehara, Hiroshi Ohmura, Ryuya Akita, Isamu Chikuma, Hiroyuki Ito, Hiroshi Eda
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Patent number: 5147009Abstract: A steering reaction force generating mechanism for generating a reaction force acting on an input shaft is provided within a cylindrical space of a housing between a lower end portion of the input shaft and an upper end portion of a pinion shaft (output shaft). The steering reaction force generating mechanism includes an input shaft accommodating section for accommodating the lower end of the input shaft together with its two control arms which protrude symmetrically and radially therefrom. A pair of reaction force chambers are provided at both sides of the input shaft accommodating section in parallel with the two control arms. Two pairs of through bores are formed respectively between one of the reaction force chambers and the input shaft accommodating section, and between the other of the reaction force chambers and the input shaft accommodating section.Type: GrantFiled: April 26, 1991Date of Patent: September 15, 1992Assignee: Nippon Seiko Kabushiki KaishaInventors: Isamu Chikuma, Hiroshi Eda
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Patent number: 5048852Abstract: A four-wheel steering apparatus comprises a front wheel steering member for steering front wheels by being displaced according to a movement of a steering wheel, a rear wheel steering mechanism for steering rear wheels, a coupling mechanism for mechanically coupling together the front wheel steering member and an input member of the rear wheel steering mechanism, and a play mechanism provided between an end of the coupling mechanism and the front wheel steering member or the input member or in an intermediate part of the coupling mechanism, the play mechanism effecting transmission of displacement only when a displacement in excess of a predetermined amount is produced in either direction from a position corresponding to a neutral position with respect to the steering angle of the front wheels.Type: GrantFiled: November 9, 1989Date of Patent: September 17, 1991Assignee: Nippon Seiko Kabushiki KaishaInventors: Isamu Chikuma, Satoru Shimada, Hiroshi Eda
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Patent number: 4982804Abstract: 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.Type: GrantFiled: February 24, 1989Date of Patent: January 8, 1991Assignees: Mazda Motor Corporation, Nippon Seiko Kabushiki KaishaInventors: Hirotaka Kanazawa, Yoichi Takeda, Yukio Noguchi, Isamu Chikuma, Satoru Shimada, Kazuo Chikaraishi
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Patent number: 4874183Abstract: A four-wheel steering apparatus of a vehicle has a front-wheel steering mechanism for steering front wheels, a rear-wheel steering mechanism for steering rear wheels, a steering gear mechanism operatively connected to the front-wheel steering mechanism and effecting a steering operation, a steering angle extracting mechanism operatively connected to the steering mechanism and extracting the steering angle of the front wheels, the steering angle extracting mechanism comprising a restraining member movable axially along the axis of the front wheels in response to the steering operation, and a string member fixed to the restraining member and displaceable in the lengthwise direction thereof in response to the movement of the restraining member, and rear-wheel steering angle control mechanism operatively connected to the steering angle extracting mechanism for controlling the amount and the direction of steer to be transmitted to the rear wheels, the rear-wheel steering angle control mechanism comprising a rotataType: GrantFiled: July 7, 1988Date of Patent: October 17, 1989Assignee: Nippon Seiko Kabushiki KaishaInventors: Isamu Chikuma, Satoru Shimada, Hiroshi Eda
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Patent number: 4834201Abstract: A neutral condition discriminating circuit is connected to a steering torque detector and it discriminates whether a torque detection value of the steering torque detector is in a neutral condition or not, that is, whether it is substantially zero or not. When it is discriminated that the non-neutral condition of the torque detection value continues for a predetermined time, a motor output decreasing circuit decreases a current supplied to a motor which produces a steering assisting torque in accordance with the torque detection value. The hysteresis characteristic of the steering torque detector, which causes the non-neutral condition to occur even when the steering wheel is not steered, can be compensated for by reducing the steering assisting torque produced by the rotor.Type: GrantFiled: March 18, 1988Date of Patent: May 30, 1989Assignee: Nippon Seiko Kabushiki KaishaInventors: Hiroya Miyazaki, Isamu Chikuma, Yasuhiko Miyaura
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Patent number: 4732231Abstract: A vehicle four wheel steering system including a rear wheel steering mechanism with a power assist device. The rear wheel steering mechanism includes a steering rod extending transversely of the vehicle and having the opposite ends connected with tie rods which are in turn connected with knuckle arms of the rear wheels. The steering rod is provided with a power cylinder in which a piston is slidably disposed. The piston is provided on the steering rod and defines hydraulic chambers in the cylinder. A control valve is provided to control hydraulic oil supply to the power cylinder. The control valve has a casing which is connected with the steering rod through an interconnecting section and hydraulic oil passages are formed in the interconnecting section for passing hydraulic oil to and from the power cylinder.Type: GrantFiled: August 11, 1986Date of Patent: March 22, 1988Assignees: Mazda Motor Corporation, Nippon Seiko Kabushiki KaishaInventors: Hirotaka Kanazawa, Teruhiko Takatani, Shigeki Furutani, Isamu Chikuma, Satoru Shimada, Hiroshi Eda