Patents by Inventor Jun Hamakita
Jun Hamakita 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: 9689464Abstract: A plane that contains a central axis of a worm shaft and that is orthogonal to a central axis of a worm wheel is arranged at a central position of the worm wheel in a tooth width direction thereof when no load is applied to a worm speed reducer. The worm wheel is formed by a cutting operation using a hob with a hob center offset from the central position toward an offset direction corresponding to a first direction along the tooth width direction. A pair of tooth flanks has different pressure angles at the central portion in the tooth width direction.Type: GrantFiled: June 11, 2015Date of Patent: June 27, 2017Assignee: JTEKT CORPORATIONInventor: Jun Hamakita
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Patent number: 9657811Abstract: A center axis of a worm shaft is offset in an offset direction with respect to a plane that is orthogonal to a center axis of a worm wheel and that passes through a central position of the worm wheel in a tooth width direction. A bias member biases a second end of the worm shaft in a preloading direction in which a center distance between the worm shaft and the worm wheel decreases. When the worm shaft is configured like a right-hand thread, in a left-handed coordinate system, a direction toward a first end of the worm shaft in an axial direction (a direction toward an electric motor) corresponds to a thumb direction. The preloading direction corresponds to an index finger direction. The offset direction corresponds to a middle finger direction.Type: GrantFiled: August 26, 2015Date of Patent: May 23, 2017Assignee: JTEKT CORPORATIONInventors: Jun Hamakita, Arata Kikuchi
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Publication number: 20160069423Abstract: A center axis of a worm shaft is offset in an offset direction with respect to a plane that is orthogonal to a center axis of a worm wheel and that passes through a central position of the worm wheel in a tooth width direction. A bias member biases a second end of the worm shaft in a preloading direction in which a center distance between the worm shaft and the worm wheel decreases. When the worm shaft is configured like a right-hand thread, in a left-handed coordinate system, a direction toward a first end of the worm shaft in an axial direction (a direction toward an electric motor) corresponds to a thumb direction. The preloading direction corresponds to an index finger direction. The offset direction corresponds to a middle finger direction.Type: ApplicationFiled: August 26, 2015Publication date: March 10, 2016Inventors: Jun HAMAKITA, Arata KIKUCHI
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Publication number: 20150377322Abstract: A plane that contains a central axis of a worm shaft and that is orthogonal to a central axis of a worm wheel is arranged at a central position of the worm wheel in a tooth width direction thereof when no load is applied to a worm speed reducer. The worm wheel is formed by a cutting operation using a hob with a hob center offset from the central position toward an offset direction corresponding to a first direction along the tooth width direction. A pair of tooth flanks has different pressure angles at the central portion in the tooth width direction.Type: ApplicationFiled: June 11, 2015Publication date: December 31, 2015Inventor: Jun HAMAKITA
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Patent number: 9061698Abstract: A speed reducer for an electric power steering system includes a worm, a worm wheel, and a housing. Only a meshing section where the worm and the worm wheel mesh with each other and a space between the worm wheel and the housing are filled with grease. The grease in the space is in contact with both tooth surfaces of the worm wheel and an inner peripheral face of the housing, the inner peripheral face facing the worm wheel.Type: GrantFiled: October 4, 2013Date of Patent: June 23, 2015Assignee: JTEKT CORPORATIONInventors: Yuji Wakugawa, Ryuji Nakata, Atsuhiro Yoshida, Wataru Yamada, Jun Hamakita, Hideyuki Honkado
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Patent number: 8991277Abstract: Each tooth of a worm wheel has a first tooth flank in which a helical surface portion is arranged on one side in a rotational axis direction of the worm wheel and a concavely curved surface portion is arranged on the other side in the rotational axis direction, and a second tooth flank in which a concavely curved surface portion is arranged on the one side in the rotational axis direction and the helical surface portion is arranged on the other side in the rotational axis direction.Type: GrantFiled: January 28, 2013Date of Patent: March 31, 2015Assignee: Jtekt CorporationInventors: Jun Hamakita, Michitoshi Mitsumaru
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Patent number: 8813904Abstract: There is provided an urging mechanism that elastically urges a second end portion of a worm shaft that is supported so as to be pivotable about a first end portion. The urging mechanism is configured to adjust a backlash between the worm shaft and a worm wheel by elastically urging the second end portion in a perpendicular direction that is perpendicular to a direction in which an inter-axis distance between the worm shaft and the worm wheel increases and decreases, in a state where increases and decreases in the inter-axis distance is prevented.Type: GrantFiled: November 19, 2012Date of Patent: August 26, 2014Assignee: JTEKT CorporationInventors: Jun Hamakita, Michitoshi Mitsumaru, Yoshitomo Nagai
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Publication number: 20140102235Abstract: A speed reducer for an electric power steering system includes a worm, a worm wheel, and a housing. Only a meshing section where the worm and the worm wheel mesh with each other and a space between the worm wheel and the housing are filled with grease. The grease in the space is in contact with both tooth surfaces of the worm wheel and an inner peripheral face of the housing, the inner peripheral face facing the worm wheel.Type: ApplicationFiled: October 4, 2013Publication date: April 17, 2014Applicant: JTEKT CORPORATIONInventors: Yuji WAKUGAWA, Ryuji NAKATA, Atsuhiro YOSHIDA, Wataru YAMADA, Jun HAMAKITA, Hideyuki HONKADO
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Patent number: 8567553Abstract: A reduction gear coupled to an electric motor includes: a first bearing that rotatably supports a first end portion of a worm shaft such that the worm shaft is allowed to oscillate in an oscillation direction about the first end portion; and a first elastic member that elastically urges a second bearing in such a direction that an axis-to-axis distance between the worm shaft and the worm wheel reduces. The first end portion and an output shaft of the electric motor are coupled by a joint. A second elastic member located between the joint and the first end portion elastically urges the worm shaft toward a second end portion and applies a preload on the first bearing. An outer ring of the first bearing is interposed in an axial direction by the third elastic member and the fourth elastic member.Type: GrantFiled: September 6, 2011Date of Patent: October 29, 2013Assignee: JTEKT CorporationInventors: Jun Hamakita, Takehito Tomita
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Patent number: 8459402Abstract: A curvature radius of a raceway groove of an inner ring of a first bearing supporting a first end portion of a worm shaft and a curvature radius of a raceway groove of an outer ring of the first bearing are larger than 50% of a diameter of each rolling element of the first bearing, whereby the worm shaft is pivotable about the first end portion. Internal clearances in the first bearing are eliminated because the first bearing is pressed in a radial direction by a pressing member. When the worm shaft vibrates relative to a housing in an axial direction, paired second elastic members and damp and absorb the vibration.Type: GrantFiled: October 28, 2011Date of Patent: June 11, 2013Assignee: JTEKT CorporationInventors: Jun Hamakita, Hirotsugu Kusano
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Patent number: 8381868Abstract: An electric power steering system includes a worm reduction gear. An end portion of worm shaft, the end portion being distant from a motor, is urged toward a worm wheel. The worm shaft is supported by a bearing at an end portion close to the motor. A movement inhibitor that includes an elastic element is arranged between the worm shaft and the bearing. The movement inhibitor allows the worm shaft to move within a predetermined range in a radial direction of the worm shaft with respect to the bearing and allows the worm shaft to move within a predetermined range in an axial direction of the worm shaft with respect to the bearing.Type: GrantFiled: August 23, 2011Date of Patent: February 26, 2013Assignee: JTEKT CorporationInventor: Jun Hamakita
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Publication number: 20120111657Abstract: A curvature radius of a raceway groove of an inner ring of a first bearing supporting a first end portion of a worm shaft and a curvature radius of a raceway groove of an outer ring of the first bearing are larger than 50% of a diameter of each rolling element of the first bearing, whereby the worm shaft is pivotable about the first end portion. Internal clearances in the first bearing are eliminated because the first bearing is pressed in a radial direction by a pressing member. When the worm shaft vibrates relative to a housing in an axial direction, paired second elastic members and damp and absorb the vibration.Type: ApplicationFiled: October 28, 2011Publication date: May 10, 2012Applicant: JTEKT CORPORATIONInventors: Jun HAMAKITA, Hirotsugu KUSANO
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Publication number: 20120061168Abstract: A reduction gear coupled to an electric motor includes: a first bearing that rotatably supports a first end portion of a worm shaft such that the worm shaft is allowed to oscillate in an oscillation direction about the first end portion; and a first elastic member that elastically urges a second bearing in such a direction that an axis-to-axis distance between the worm shaft and the worm wheel reduces. The first end portion and an output shaft of the electric motor are coupled by a joint. A second elastic member located between the joint and the first end portion elastically urges the worm shaft toward a second end portion and applies a preload on the first bearing. An outer ring of the first bearing is interposed in an axial direction by the third elastic member and the fourth elastic member.Type: ApplicationFiled: September 6, 2011Publication date: March 15, 2012Applicant: JTEKT CORPORATIONInventors: Jun HAMAKITA, Takehito TOMITA
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Publication number: 20120048640Abstract: An electric power steering system includes a worm reduction gear. An end portion of worm shaft, the end portion being distant from a motor, is urged toward a worm wheel. The worm shaft is supported by a bearing at an end portion close to the motor. A movement inhibitor that includes an elastic element is arranged between the worm shaft and the bearing. The movement inhibitor allows the worm shaft to move within a predetermined range in a radial direction of the worm shaft with respect to the bearing and allows the worm shaft to move within a predetermined range in an axial direction of the worm shaft with respect to the bearing.Type: ApplicationFiled: August 23, 2011Publication date: March 1, 2012Applicant: JTEKT CORPORATIONInventor: Jun HAMAKITA
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Publication number: 20040242334Abstract: An electric power steering device for transmitting a rotation of a motor for assisting operation of steering which is reduced via a reduction gear to a steering mechanism includes: a male type joint member and a female type joint member which are jointed each other for transmitting the rotation of the motor to the reduction gear; and lubricant including base oil having kinetic viscosity of 1000 to 5000 mm2/s (40° C.), worked penetration of which is not more than 300, and which is charged between the male type joint member and the female type joint member.Type: ApplicationFiled: March 10, 2004Publication date: December 2, 2004Applicant: Koyo Seiko Co., Ltd.Inventors: Jun Hamakita, Yoshikazu Kawada