Patents by Inventor Shuji Takuma
Shuji Takuma 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: 11092107Abstract: An engine combustion chamber structure includes a combustion chamber of an engine and a fuel injection valve. The fuel injection valve injects fuel toward a cavity in a crown face of a piston. The cavity includes a first cavity provided in a radially central region of the crown face with a first bottom having a first depth, a second cavity provided in an outer side of the first cavity with a second bottom having a second depth being smaller than the first depth, a connecting portion, and a standing wall region disposed further in a radially outer side than the second bottom of the second cavity. The second bottom is provided lower than an upper end, of the connecting portion. A lower section of the standing wall region is provided further in a radially inner side than an upper edge of the standing wall region.Type: GrantFiled: August 23, 2018Date of Patent: August 17, 2021Assignee: Mazda Motor CorporationInventors: Sangkyu Kim, Takashi Sumimoto, Daisuke Shimo, Tomonori Harada, Shintaro Okada, Shuji Takuma
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Patent number: 10982588Abstract: A cavity includes a lower-side cavity, an upper-side cavity, a first lip and a second lip. The upper-side cavity has a guide curved surface which extends along a circumference of a first imaginary circle in a section along a cylinder-axis direction, and the first lip has a curved surface which extends along a circumference of a second imaginary circle in a section along the cylinder-axis direction. An angle X which a cylinder axis makes with a common tangential line of the first imaginary circle and the second imaginary circle is set as 75°<X<80°. The guide curved surface is configured such that an angle Y of this guide curved surface which occupies at the circumference of the first imaginary circle is set as 80°<Y<(180°?X).Type: GrantFiled: January 10, 2020Date of Patent: April 20, 2021Assignee: MAZDA MOTOR CORPORATIONInventors: Sangkyu Kim, Takashi Sumimoto, Shintaro Okada, Daisuke Shimo, Shuji Takuma
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Publication number: 20200392919Abstract: An engine combustion chamber structure includes a combustion chamber of an engine and a fuel injection valve. The fuel injection valve injects fuel toward a cavity in a crown face of a piston. The cavity includes a first cavity that is provided in a radially central region of the crown face with a first bottom having a first depth, a second cavity provided in an outer side of the first cavity with a second bottom having a second depth being smaller than the first depth, a connecting portion, and a standing wall region disposed further in a radially outer side than the second bottom of the second cavity. The second bottom is provided lower than an upper end, of the connecting portion. A lower section of the standing wall region is provided further in a radially inner side than an upper edge of the standing wall region.Type: ApplicationFiled: August 23, 2018Publication date: December 17, 2020Applicant: Mazda Motor CorporationInventors: Sangkyu KIM, Takashi SUMIMOTO, Daisuke SHIMO, Tomonori HARADA, Shintaro OKADA, Shuji TAKUMA
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Publication number: 20200232380Abstract: A cavity includes a lower-side cavity, an upper-side cavity, a first lip and a second lip. The upper-side cavity has a guide curved surface which extends along a circumference of a first imaginary circle in a section along a cylinder-axis direction, and the first lip has a curved surface which extends along a circumference of a second imaginary circle in a section along the cylinder-axis direction. An angle X which a cylinder axis makes with a common tangential line of the first imaginary circle and the second imaginary circle is set as 75°<X<80°. The guide curved surface is configured such that an angle Y of this guide curved surface which occupies at the circumference of the first imaginary circle is set as 80°<Y<(180°?X).Type: ApplicationFiled: January 10, 2020Publication date: July 23, 2020Applicant: MAZDA MOTOR CORPORATIONInventors: Sangkyu Kim, Takashi Sumimoto, Shintaro Okada, Daisuke Shimo, Shuji Takuma
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Patent number: 10041395Abstract: A structure of a combustion chamber is provided. The structure includes a cavity formed in a central part of a crown surface of a piston and a wall surface constituting the cavity. The wall surface has a central ridge portion bulging farther toward a bottom surface of a cylinder head toward a center of the cavity, a periphery concave portion formed radially outward of the central ridge portion to concave radially outward, and a lip portion formed between the periphery concave portion and an opening edge of the cavity to convex radially inward. An outer circumferential part of the crown surface has a first portion and a second portion located radially outward of the first portion. A stepped portion is formed between the first and second portions. A stepped portion volume ratio of a stepped portion volume to a top dead center volume is set to 0.1 or smaller.Type: GrantFiled: May 22, 2015Date of Patent: August 7, 2018Assignee: Mazda Motor CorporationInventors: Daisuke Shimo, Sangkyu Kim, Makoto Namba, Masahiro Miyazaki, Yudai Kato, Shuji Takuma, Tadashi Tadokoro
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Patent number: 9926998Abstract: An engine piston structure includes: a piston (1); a connecting rod (10) having a small end part (10a) coupled to the piston (1), and having a large end part (10b) coupled to a crankshaft; a piston pin (2) through which the piston (1) and the small end part (10a) of the connecting rod (10) are coupled together and which has a hollow cross section; and at least one dynamic vibration absorber (20) provided inside the piston pin (2) to reduce resonance of the piston (1), the piston pin (2), and the small end part (10a) of the connecting rod (10) in combination with respect to the large end part (10b) of the connecting rod (10) during a combustion stroke.Type: GrantFiled: August 9, 2013Date of Patent: March 27, 2018Assignee: MAZDA MOTOR CORPORATIONInventors: Yasunori Kanda, Tsunehiro Mori, Yasuhiro Sudou, Masakazu Kikuchi, Kazuo Toyoda, Tetsuya Hanzawa, Yukiyoshi Fukuda, Akira Sumitani, Masahiro Koizumi, Koichi Hirata, Shuji Takuma, Kouji Kubo, Kazuya Nishimori
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Patent number: 9791045Abstract: An oil ring to be attached to a ring groove of a piston for an engine is provided. The oil ring includes two annular ring bodies having a common axis and arranged in tandem, and an expander for biasing the ring bodies radially outward. A sliding surface is formed at an outer circumference of each ring body to bulge radially outward and slides on a cylinder inner circumferential surface. The sliding surface of one of the ring bodies has a tip portion and first and second curved surfaces. In cross sections of the first and second curved surfaces, the first and second curved surfaces are connected while tangent lines to the cross sections at the tip portion align with each other, and when positional change rates are compared between points on the first and second curved surfaces, a change rate of the first curved surface is lower.Type: GrantFiled: August 13, 2015Date of Patent: October 17, 2017Assignee: Mazda Motor CorporationInventors: Masaki Fukuma, Hiroaki Muranaka, Shuma Aoki, Shuji Takuma
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Patent number: 9556821Abstract: A piston structure for an engine is provided. The piston structure includes a piston for reciprocating within a cylinder, a connecting rod having a smaller-end part and a larger-end part in both ends, respectively, the smaller-end part coupled to the piston, the larger-end part coupled to a crankshaft, a cross-sectionally hollow piston pin coupling the piston to the smaller-end part, and a dynamic absorber provided inside the piston pin, including a fixed part fixed to the piston pin and a movable part pivotally supported by the fixed part, and for suppressing the piston, the piston pin, and the smaller-end part from integrally resonating with respect to the larger-end part of the connecting rod on combustion stroke. The dynamic absorber includes an assemblable dynamic absorber in which the movable part is formed by attaching a mass adjusting part to the fixed part.Type: GrantFiled: August 20, 2014Date of Patent: January 31, 2017Assignee: Mazda Motor CorporationInventors: Koichi Hirata, Mitsutaka Yamaya, Shuji Takuma, Yasunori Kanda, Tatsuya Kobayashi, Takeshi Motomuro
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Patent number: 9347396Abstract: A piston pin structure for an engine is provided, which suppresses integral resonance of a piston, a piston pin, and a smaller end part of a connecting rod with respect to a larger end part of the connecting rod on the combustion stroke, as well as suppresses an increase of noise on other strokes, and restricts the fixed dynamic absorber inside the piston pin from coming off and ensures a coming-off function. The piston pin structure may include a dynamic absorber including a fixed part fixed to a piston pin, a movable part extending in the axial direction of the piston pin, and a supporting part for swingably supporting the movable part with respect to the fixed part. A restriction mechanism for mechanically restricting the movement of the dynamic absorber in the axial direction may also be included.Type: GrantFiled: August 29, 2014Date of Patent: May 24, 2016Assignee: Mazda Motor CorporationInventors: Koichi Hirata, Yasunori Kanda, Kouji Kubo, Mitsutaka Yamaya, Shuji Takuma, Tatsuya Kobayashi, Takeshi Motomuro
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Publication number: 20160076649Abstract: An oil ring to be attached to a ring groove of a piston for an engine is provided. The oil ring includes two annular ring bodies having a common axis and arranged in tandem, and an expander for biasing the ring bodies radially outward. A sliding surface is formed at an outer circumference of each ring body to bulge radially outward and slides on a cylinder inner circumferential surface. The sliding surface of one of the ring bodies has a tip portion and first and second curved surfaces. In cross sections of the first and second curved surfaces, the first and second curved surfaces are connected while tangent lines to the cross sections at the tip portion align with each other, and when positional change rates are compared between points on the first and second curved surfaces, a change rate of the first curved surface is lower.Type: ApplicationFiled: August 13, 2015Publication date: March 17, 2016Inventors: Masaki Fukuma, Hiroaki Muranaka, Shuma Aoki, Shuji Takuma
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Publication number: 20150354439Abstract: A structure of a combustion chamber is provided. The structure includes a cavity formed in a central part of a crown surface of a piston and a wall surface constituting the cavity. The wall surface has a central ridge portion bulging farther toward a bottom surface of a cylinder head toward a center of the cavity, a periphery concave portion formed radially outward of the central ridge portion to concave radially outward, and a lip portion formed between the periphery concave portion and an opening edge of the cavity to convex radially inward. An outer circumferential part of the crown surface has a first portion and a second portion located radially outward of the first portion. A stepped portion is formed between the first and second portions. A stepped portion volume ratio of a stepped portion volume to a top dead center volume is set to 0.1 or smaller.Type: ApplicationFiled: May 22, 2015Publication date: December 10, 2015Inventors: Daisuke Shimo, Sangkyu Kim, Makoto Namba, Masahiro Miyazaki, Yudai Kato, Shuji Takuma, Tadashi Tadokoro
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Publication number: 20150219181Abstract: An engine piston structure includes: a piston (1); a connecting rod (10) having a small end part (10a) coupled to the piston (1), and having a large end part (10b) coupled to a crankshaft; a piston pin (2) through which the piston (1) and the small end part (10a) of the connecting rod (10) are coupled together and which has a hollow cross section; and at least one dynamic vibration absorber (20) provided inside the piston pin (2) to reduce resonance of the piston (1), the piston pin (2), and the small end part (10a) of the connecting rod (10) in combination with respect to the large end part (10b) of the connecting rod (10) during a combustion stroke.Type: ApplicationFiled: August 9, 2013Publication date: August 6, 2015Applicant: MAZDA MOTOR CORPORATIONInventors: Yasunori Kanda, Tsunehiro Mori, Yasuhiro Sudou, Masakazu Kikuchi, Kazuo Toyoda, Tetsuya Hanzawa, Yukiyoshi Fukuda, Akira Sumitani, Masahiro Koizumi, Koichi Hirata, Shuji Takuma, Kouji Kubo, Kazuya Nishimori
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Publication number: 20150075479Abstract: A piston pin structure for an engine is provided, which suppresses integral resonance of a piston, a piston pin, and a smaller end part of a connecting rod with respect to a larger end part of the connecting rod on the combustion stroke, as well as suppresses an increase of noise on other strokes, and restricts the fixed dynamic absorber inside the piston pin from coming off and ensures a coming-off function. The piston pin structure may include a dynamic absorber including a fixed part fixed to a piston pin, a movable part extending in the axial direction of the piston pin, and a supporting part for swingably supporting the movable part with respect to the fixed part. A restriction mechanism for mechanically restricting the movement of the dynamic absorber in the axial direction may also be included.Type: ApplicationFiled: August 29, 2014Publication date: March 19, 2015Inventors: Koichi Hirata, Yasunori Kanda, Kouji Kubo, Mitsutaka Yamaya, Shuji Takuma, Tatsuya Kobayashi, Takeshi Motomuro
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Publication number: 20150075478Abstract: A piston structure for an engine is provided. The piston structure includes a piston for reciprocating within a cylinder, a connecting rod having a smaller-end part and a larger-end part in both ends, respectively, the smaller-end part coupled to the piston, the larger-end part coupled to a crankshaft, a cross-sectionally hollow piston pin coupling the piston to the smaller-end part, and a dynamic absorber provided inside the piston pin, including a fixed part fixed to the piston pin and a movable part pivotally supported by the fixed part, and for suppressing the piston, the piston pin, and the smaller-end part from integrally resonating with respect to the larger-end part of the connecting rod on combustion stroke. The dynamic absorber includes an assemblable dynamic absorber in which the movable part is formed by attaching a mass adjusting part to the fixed part.Type: ApplicationFiled: August 20, 2014Publication date: March 19, 2015Inventors: Koichi Hirata, Mitsutaka Yamaya, Shuji Takuma, Yasunori Kanda, Tatsuya Kobayashi, Takeshi Motomuro