Patents by Inventor Shoichi Ishikawa
Shoichi Ishikawa 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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Publication number: 20070266819Abstract: A rigid internal gear and a flexible external gear of a wave gear drive are spur gears of module m. The number of teeth of the external gear is smaller by 2n (n is a positive integer) than that of the internal gear. The deflection of the major axis of the elliptical rim neutral line on the principal cross-section of the external gear is set at 2K mn (K<1). On the principal cross-section, the meshing of both gears is approximated by rack meshing. The locus M of movement of a tooth of the external gear caused by the rotation of a wave generator is determined. A part AC of the locus M of movement from the inflection point A of the locus M of movement to the deepest position B of meshing is determined on the entering side of meshing of the teeth toward the major axis of the locus M of movement.Type: ApplicationFiled: June 21, 2004Publication date: November 22, 2007Applicant: HARMONIC DRIVE SYSTEMS INC.Inventors: Shoichi Ishikawa, Noboru Takizawa
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Publication number: 20070180947Abstract: A wave gear drive comprises a circular rigid internal gear and a flexible external gear inside the rigid internal gear. A wave generator in the flexible external gear flexes the flexible external gear into an elliptical shape. The cross-section of the flexible external gear perpendicular to the axis at a point in the tooth trace direction of the flexible external gear is set as the main cross-section. The rigid internal gear and flexible external gear are gears with a module m, and the flexible external gear has a number of teeth that is smaller than the number of teeth of the rigid internal gear. The moving route M of a tooth of the flexible external gear with respect to a tooth of the rigid internal gear that accompanies rotation of the wave generator when meshing of the teeth in the main cross-section is approximated by rack meshing.Type: ApplicationFiled: January 11, 2007Publication date: August 9, 2007Applicant: HARMONIC DRIVE SYSTEMS INC.Inventors: Shoichi Ishikawa, Noboru Takizawa
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Publication number: 20070022838Abstract: A wave gear drive, wherein a rigid internal gear is formed in a spur gear with a module m and a flexible external gear is formed in a conical gear having an opening side front end with a module m. The number of the teeth of the external gear is reduced by the quantity of 2n (n is a positive integer) less than that of the internal gear, and the amount of the deflection of the major axis of the elliptic rim neutral line of the external gear is set to 2 ?mn (?>1) at the opening side front end thereof.Type: ApplicationFiled: May 26, 2004Publication date: February 1, 2007Applicant: Harmonic Drive Systems Inc.Inventor: Shoichi Ishikawa
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Patent number: 7117759Abstract: A wave gear drive in which wide-area meshing of the rigid internal gear and flexible external gear is achieved, reducing stresses on the bottom rim of the gear teeth and in the vicinity of the major axis of the inner ring surfaces of the wave generator, thereby improving the load capabilities of the wave gear drive.Type: GrantFiled: August 27, 2004Date of Patent: October 10, 2006Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Publication number: 20050177576Abstract: The present invention enables automatic creation of filing folders, without requiring a user to create filing folders, before an operation of reading documents by use of a scanner and filing them. A folder configuration including folders for storing receipt data is created on mail software. A folder configuration analysis section obtains and analyzes the folder configuration (or data management configuration) of the mail software. A folder configuration comparison/creation section creates in a file system a folder configuration identical to the analyzed folder configuration, and performs file management. With this configuration, a user can execute filing processing for the folder configuration which is identical to the folder configuration on the mail software, which the user is accustomed to using. Therefore, the user can store files in proper folders without confusion.Type: ApplicationFiled: August 1, 2003Publication date: August 11, 2005Inventors: Shoichi Ishikawa, Norio Kanemitsu, Katsushi Sasakawa, Jun Shida
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Publication number: 20050044986Abstract: A wave gear drive in which wide-area meshing of the rigid internal gear and flexible external gear is achieved, reducing stresses on the bottom rim of the gear teeth and in the vicinity of the major axis of the inner ring surfaces of the wave generator, thereby improving the load capabilities of the wave gear drive.Type: ApplicationFiled: August 27, 2004Publication date: March 3, 2005Applicant: Harmonic Drive Systems Inc.Inventor: Shoichi Ishikawa
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Patent number: 6799489Abstract: In a principal section of the flexible external gear of a wave gear drive, a position away from the major axis of an elliptically shaped neutral line of the rim of the flexible external gear is defined as the center position of the teeth meshing, and &thgr; is the angle of inclination of the tangent of that position with a point along the neutral line of the rim. The amount of flexing w of the principal section is defined according to the angle of inclination &thgr;, the number of teeth zF of the flexible external gear, the number of teeth zC of the rigid internal gear, radius ro of the pitch circle of the flexible external gear, and the radius rn of the neutral curve of the rim prior to deformation.Type: GrantFiled: March 17, 2003Date of Patent: October 5, 2004Assignee: Harmonic Drive Systems Inc.Inventor: Shoichi Ishikawa
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Publication number: 20030159539Abstract: In a principal section of the flexible external gear of a wave gear drive, a position away from the major axis of an elliptically shaped neutral line of the rim of the flexible external gear is defined as the center position of the teeth meshing, and &thgr; is the angle of inclination of the tangent of that position with a point along the neutral line of the rim. The amount of flexing w of the principal section is defined according to the angle of inclination &thgr;, the number of teeth zF of the flexible external gear, the number of teeth zC of the rigid internal gear, radius ro of the pitch circle of the flexible external gear, and the radius rn of the neutral curve of the rim prior to deformation.Type: ApplicationFiled: March 17, 2003Publication date: August 28, 2003Inventor: Shoichi Ishikawa
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Patent number: 6526849Abstract: A flexible meshing type gear device includes a rigid internal gear, a flexible external gear and a wave generator, wherein the flexible external gear includes a cylindrical body and external teeth formed on the outer surface of the cylindrical body. The basic tooth profile of the flexible external gear having a flexing coefficient of smaller than 1 is given the shape of a convex arc, and a normal at the inflection point of the movement locus described by the center of the convex-arc tooth profile relative to the teeth of the rigid internal gear and an evolute of the locus are newly introduced, thereby clarifying the interference limit of the tooth profile and thus enabling maximization of the tooth height of the concave tooth profile portion of the rigid internal gear and the convex tooth profile portion of the flexible external gear.Type: GrantFiled: November 17, 2000Date of Patent: March 4, 2003Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 6467375Abstract: A flexible meshing type gear device has a rigid internal gear, a flexible external gear disposed inside the internal gear and a wave generator for flexing the external gear into an elliptical shape. One circle of curvature at the point of contact of the involute curve making contact at the meshing center position is made coincident with a tooth profile circle of curvature satisfying the Euler-Savary equation that applies between the tooth profile curvatures at the tooth profile contact points of speed change gears, and the other tooth profile circle of curvature of the equation is defined in the vicinity of the circle of curvature of the other involute curve.Type: GrantFiled: November 17, 2000Date of Patent: October 22, 2002Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 6167783Abstract: The meshing of the rigid internal gear and the cup-shaped flexible external gear of a flexible meshing type gear device is simulated with racks, similarity transformation is effected on the composite curve consisting of the envelope obtained by axially projecting the movement loci of the rack teeth relative to each other from the tooth trace opening portion to the tooth trace inner extremity in sections perpendicular to the axis and the movement locus in the vicinity of the tooth trace inner extremity, and the resulting curve is adopted as the basic addendum profile of the external teeth and the internal teeth.Type: GrantFiled: July 27, 1999Date of Patent: January 2, 2001Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 5918508Abstract: A strain wave gearing is provided with tooth profiles formed taking into account tooth inclination and change in the movement locus of the origin of the tooth profile coordinates, thereby obtaining proper meshing over a wide range. Specifically, a tooth module is denoted as m; the number of teeth of the rigid internal gear as z.sub.C ; the number of teeth, the deddendum, the thickness of the tooth bottom rim and the radius of the neutral circle of the rim of the flexible external gear as z.sub.F, h.sub.fF, t and r.sub.n, respectively; the coefficient of tooth thickness increase of the rigid internal gear and the coefficient of tooth thickness decrease of the flexible external gear both as .tau.; and an auxiliary angle variable .eta.. The basic addendum profiles of both gears are formed according to two equations, taking an x-axis on a datum line and a y-axis on the tooth center line and taking .+-. of the first equation as positive for the flexible external gear and as negative for the rigid internal gear.Type: GrantFiled: September 24, 1997Date of Patent: July 6, 1999Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 5782143Abstract: The amount of radial flexing (w) in a basic section defined perpendicular to the axis of the flexible external gear (3) at a prescribed point on the tooth trace of the flexible external gear (3) is defined to be an amount of negative deviation flexing smaller than the normal amount of flexing (W.sub.0) The rigid internal gear (2) and the flexible external gear (3) are both spur gears and the number of teeth of the flexible external gear (3) is 2n (n being a positive integer) fewer than that of the rigid internal gear (2). The working tooth profile of one of the gears (2, 3) is defined to be a convex curve whose shape is or approximates a convex curve (L2(O,B)) obtained by similarity transformation of a peak portion (L1(O,A) of the rack-approximated moving path (L1) of a tooth of the gear with respect to the other gear in the basic section of the tooth trace perpendicular to the axis, the portion being convex relative to the other gear, at an enlargement ratio (.lambda.Type: GrantFiled: October 3, 1996Date of Patent: July 21, 1998Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 5687620Abstract: In a meshing type gear device (1), spur gears are used for both a rigid internal gear (2) and a flexible external gear (3), and the number of teeth of the flexible gear (3) is made greater by two than that of the rigid internal gear (2). The tooth profile of the flexible external gear (3) is made convex and the shape thereof is that of a curve AC obtained by subjecting a gear tooth portion (curve portion between A and B), which, at the moving path L that the external gear describes relative to the internal gear, as determined by rack approximation, is convex relative to the internal gear, to similarity transformation at a reduction ratio .lambda. using the limiting point A of the contact between the two gears on the path as the origin, while the tooth profile of the rigid internal gear is made concave and the shape thereof is that of a curve AD obtained by subjecting the same portion convex relative to the internal gear at the moving path to similarity transformation at an enlargement ratio (1+.lambda.Type: GrantFiled: February 15, 1996Date of Patent: November 18, 1997Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 5485766Abstract: In a cup-shaped flexing contact gear (1), both a rigid internal gear (2) and a flexible external gear (3) are made to be non-profile-shifted spur gears, an opening (3a) of the flexible external gear (3) is set in a state of negative deviation wherein a deflection of the opening is lower in value than a normal deflection; a moving locus is obtained through rack approximation of teeth of the external gear to the internal gear at respective sections of rotation of tooth trace of the flexible external gear (3), an envelope (e) is obtained by overlapping the moving locus on one of sections of rotation, another moving locus is obtained in a section of rotation at the end portion of tooth trace on the side of a diaphragm or in the vicinity of the outside of the end portion and is smoothly connected to the envelope to thereby obtain a composite curve (L).Type: GrantFiled: September 14, 1994Date of Patent: January 23, 1996Assignee: Harmonic Drive Systems, Inc.Inventor: Shoichi Ishikawa
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Patent number: 5458023Abstract: In a flexing contact type gear drive (1), the respective tooth profiles of the internal gear (2) and external gear (3) are constructed such that the tooth face portion is formed of a straight line AM disposed in the vicinity of a datum point, a first convex circular arc (AB) smoothly connected thereto and a second convex circular arc (BC) smoothly connected to the first convex circular arc and having a radius of curvature larger than the first convex circular arc, while, the dedendum portion excluding the root is created by a standard rack consisting of a tooth profile formed by a curve point-symmetrical with respect to the datum point to the tooth profile at the tooth face or a curve obtained by correcting the above curve.Type: GrantFiled: September 15, 1994Date of Patent: October 17, 1995Assignee: Harmonic Drive Systems, Inc.Inventors: Shoichi Ishikawa, Yoshihide Kiyosawa
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Patent number: 4974470Abstract: A strain wave gearing comprising a circular spline, flexspline inside the circular spline, a wave generator for deforming the flexspline into, for example, an ellipsoid and a motor for rotating the wave generator to produce a relative rotation between the flexspline and the circular spline. The strain wave gearing is sometimes termed a harmonic drive transmission, and there is a type of gearing called flat-shaped strain wave gearing which is composed of two circular splines juxtaposed with each other, a flexspline in the circular splines having the same number of teeth as the first circular spline, a wave generator for deforming the flexspline into an ellipsoid and a motor for rotating the wave generator. In the flat-shaped gearing, each tooth of the flexspline is provided with a convex tooth face and a concave tooth flank.Type: GrantFiled: September 15, 1988Date of Patent: December 4, 1990Assignee: Harmonic Drive Systems Inc.Inventors: Shoichi Ishikawa, Yoshihide Kiyosawa
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Patent number: 4823638Abstract: A strain wave gearing comprising a circular spline, flexspline disposed inside the circular spline, a wave generator for deforming the flexspline into, for example, an ellipsoid and a motor for rotating the wave generator to produce a relative rotation between the flexspline and the circular spline. The strain wave gearing is sometimes termed a harmonic drive transmission. In the strain wave gearing, the tooth face of each of the splines is formed in line with a mapping curve which is a similarity transformation having a reduced scale of 1/2 applied to a movement locus of the flexspline to the circular spline in accordance with the configuration of the wave generator, the transformation being effected on a reference point where the splines are transferred from the contact condition to a disengagement from each other. Thus, the teeth of the flexspline engage with those of the circular spline in the broad extent of the engagement region.Type: GrantFiled: October 27, 1987Date of Patent: April 25, 1989Assignee: Harmonic Drive Systems Inc.Inventor: Shoichi Ishikawa
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Patent number: 4121482Abstract: A W-N gear which has a surface strength at least nearly maximized for a given addendum and minimum pressure angle is realized by selecting a mean radius for the convex and concave circular arcs of the tooth profile in an appropriate range. Also, a dual=line mesh W-N gear of the character described which has a requisite face width minimized is obtained by selecting a mean arc radius which lies in the range referred to above and enables the addendum and dedendum points of meshing contact to appear at equal angle intervals.Type: GrantFiled: August 10, 1977Date of Patent: October 24, 1978Assignee: Kabushiki Kaisha Hasegawa HagurumaInventors: Shoichi Ishikawa, Kiyoshi Kotake, Seishi Honma
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Patent number: 4051745Abstract: A single-flank or double-flank type W-N gear each of the convex or concave tooth flanks of which is formed of a plurality of circular arcs (which participate in meshing engagement and) the centers of which (arcs) are arranged on the pitch line or in the vicinity thereof in spaced-apart relation to each other and an intermediate curved line or lines interconnecting the circular arcs. Meshing contact at any instant is obtained at different locations mutually spaced in the direction of tooth trace and stress concentration at the root of the teeth is minimized.Type: GrantFiled: April 15, 1976Date of Patent: October 4, 1977Assignee: Kabushiki Kaisha Hasegawa HagurumaInventor: Shoichi Ishikawa