speed reducer

Abstract

This enables the creation of a thinner gearbox than conventional gearboxes without compromising performance or characteristics. [Solution] In a reduction gear 1 comprising an eccentric shaft 4 in which eccentric parts 41 and 42 perform eccentric motion due to the rotation of the shaft, planetary gears 51 and 52 rotatably supported by the eccentric parts 41 and 42 and performing eccentric motion in synchronization with the eccentric motion of the eccentric shaft 4, a case 9 to which a plurality of outer peripheral pins 6 that function as internal teeth for the planetary gears 51 and 52 are rotatably attached, and a carrier 7 which is rotatably supported by the eccentric shaft 4 and consists of covers 71 and 72 that clamp the planetary gears 51 and 52 and outputs the rotation of the planetary gears 51 and 52, the planetary gears 51 and 52 and the covers 71 and 72 are manufactured by reducing their size by the amount by which the torsional rigidity of each part is increased by shot peening when processing the material, and shot peening is applied to the surface of the parts.

Claims

1. An eccentric shaft having an eccentric portion, wherein the shaft rotates due to the rotation of the motor, causing the eccentric portion to perform an eccentric motion, A planetary gear is rotatably supported at the eccentric portion of the eccentric shaft and performs eccentric motion around the axial center of the eccentric shaft due to the eccentric motion of the eccentric portion, A case in which a plurality of outer peripheral pins, arranged around the planetary gear and functioning as internal teeth relative to the outer teeth of the planetary gear, are rotatably mounted on the inner circumferential surface, The shaft includes two covers that are rotatably supported at both ends of the eccentric portion and that clamp the planetary gear, and a carrier that outputs the rotation of the planetary gear based on the eccentric motion of the eccentric portion to the outside, In a speed reducer equipped with, At least the planetary gear and the carrier components are manufactured by reducing the size of each component by the amount by which the torsional rigidity of each component increases when shot peening is applied during the manufacturing process of the material, and then the shot peening is applied to each manufactured component to increase the torsional rigidity. A gearbox characterized by the following features.

2. The case, after the shot peening, undergoes surface treatment of ultra-smooth polishing and oil reservoir processing in the grooves where the outer pins are attached. The gearbox according to feature 1.

3. The material of the carrier and the case is ductile cast iron. The gearbox according to feature 1 or 2.

4. Each component of the eccentric shaft, planetary gear, and multiple outer pins is manufactured by processing the material, followed by heat treatments of quenching, ultra-sub-zeroing, and tempering in that order, and then surface treatments of shot peening, ultra-smooth polishing, and oil reservoir machining in that order. A gearbox according to any one of claims 1 to 3.

5. The two lids are disc-shaped with a first through-hole drilled in the center. The two covers are rotatably mounted on the eccentric shaft with tapered roller bearings interposed between the first through hole and the eccentric shaft, and are rotatably mounted on the case with angular contact bearings interposed between the outer circumference and the inner circumference of the case. The planetary gear is disc-shaped with a second through-hole drilled in its center. The planetary gear is rotatably mounted on the eccentric shaft with retained needle rollers interposed between the second through hole and the eccentric portion. The aforementioned tapered roller bearing and angular contact bearing have shot peening applied to the entire raceway, and the surface treatments of ultra-smooth polishing and oil reservoir processing are applied in this order to the parts of the raceway that the rollers contact. The aforementioned retained needle roller has been shot peened over its entire surface, and the circumferential surface of the needle roller has been subjected to ultra-smooth polishing and oil reservoir processing in that order. A gearbox according to any one of claims 1 to 4.

6. The material of the eccentric shaft, the planetary gear, and the plurality of outer pins is structural steel material with guaranteed hardenability. A gearbox according to any one of claims 1 to 5.

7. A second spur gear is fixed to one end of the eccentric shaft, meshing with a first spur gear connected to the rotor of the motor, and reducing the rotational speed of the first spur gear and transmitting it to the eccentric shaft. The first and second spur gears undergo heat treatments of quenching, ultra-sub-zeroing, and tempering in that order, followed by surface treatments of shot peening, ultra-smooth polishing, and oil reservoir machining in that order. A gearbox according to any one of claims 1 to 6.

8. A first reduction is performed by the gear mechanism of the first spur gear and the second spur gear, and a second reduction is performed by the gear mechanism of the planetary gear and the case. The gearbox according to feature 7.

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