| 摘要 |
PURPOSE:To improve the capacity efficiency by forming a convex tooth in the longer- diameter part of a rotor body formed through the pitch curve of a noncircular gear, and forming, in the shorter-diameter part, a concaved tooth which can be meshed with the convex tooth in the above-described longer-diameter part and reducing the leak from the gap between the inner peripheral surface of a casing. CONSTITUTION:The outer peripheral surface of a noncircular rotor body 11 having an elliptical form is formed through the pitch curve of two-leaf ellipse- series noncircular gear, and a convex tooth 14 having a top tooth thickness (a) is formed in the longer- diameter part 12, and a concaved tooth 15 which can be meshed with the above-described convex tooth 14 is formed onto the shorter-diameter part 13. Timing gears 6 and 6 which engage each other are fitted in the projection parts of the rotary shafts 18 and 18 similarly in the former. Therefore, the convex tooth 14 in the above-described longer-diameter part 12 shifts along the inner peripheral surface 17a of a casing 17, and though a certain gap 20 is formed between the addendum 14a of the convex tooth 14 and the peripheral surface 17a of the casing 17, the gap (b) is formed, since the top tooth thickness (a) is provided. Because of the gap width (b), the resistance of the fluid which flows in the gap 20 formed between the addendum 14a and the inner peripheral surface 17a increases, and the amount of leak can be reduced.
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