Abstract: A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.

Abstract: A speed reducer includes an input shaft, an input gear, a fixing gear and an output gear. The input shaft includes an eccentric structure. The input gear is disposed on the eccentric structure and includes first teeth of which each with a first contact portion and a second contact portion. The fixing gear and the output gear are disposed corresponding to the input gear, wherein the fixing gear includes second teeth, and the second teeth are in contact with the first contact portions, wherein the output gear includes third teeth, and the third teeth are in contact with the second contact portions. A first tooth number difference between the first teeth and the second teeth is different from a second tooth number difference between the first teeth and the third teeth.

Abstract: A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.

Abstract: A cycloid speed reducer includes a weight element, an input shaft and a cycloid disc. The weight element is disposed within an accommodation space of the cycloid disc. An eccentric part is disposed on the input shaft. Since the length of the input shaft is reduced, the overall length of the cycloid speed reducer is shortened. Moreover, the mass center of the weight element and the mass center of the eccentric part and the cycloid disc are arranged along the same axial direction. That is, the line passing through the mass center of the weight element and the mass center of the eccentric part and the cycloid disc is perpendicular to the input shaft. Consequently, the efficacy of the dynamic balance of the cycloid speed reducer is enhanced.

Abstract: A speed reducing device includes a motor and a speed reducing mechanism. The speed reducing mechanism includes at least one roller assembly, a cycloid disc, at least one fixing disc and a positioning assembly. The roller assembly is disposed within a rotor portion of the motor. While the roller assembly is rotated with the rotor portion, the roller assembly is eccentrically revolved. The roller assembly includes a wheel disc and at least one roller. The cycloid disc includes a main body and at least one cycloid tooth structure. The cycloid tooth structure is protruded from an outer periphery of the main body and in contact with the corresponding roller. While the roller assembly is eccentrically revolved, the at least one cycloid tooth structure is pushed against the corresponding roller, so that the cycloid disc is correspondingly rotated.

Abstract: A bearing assembly and a rotary shaft apparatus employing the same are provided. The bearing assembly is rotatably coupled with a first shaft and a second shaft. The first bearing housing includes a first annular recess having a first axial depth. The first bearing is connected with the first annular recess and the first shaft and has a first axial thickness. The second bearing housing includes a second annular recess having a second axial depth. The second bearing is connected with the first annular recess, the second annular recess and the second shaft and has a second axial thickness. The spacer is disposed between the first bearing and the second bearing and has a third axial thickness. The sum of the first axial thickness, the second axial thickness and the third axial thickness is greater than the sum of the first axial depth and the second axial depth.

Abstract: A two-stage cycloid speed reducer comprises two rotating disc assemblies. Each rotating disc assembly comprises two cycloid discs. In other words, the cycloid speed reducer has four cycloid discs to be in contact with the corresponding rollers. Consequently, the load withstood by each cycloid disc is reduced. Since the cycloid speed reducer has stronger structural strength, the cycloid speed reducer can be applied to the high-load circumstance. Moreover, an eccentric assembly of the eccentric device includes a plurality of eccentric cylinders. The eccentric cylinders are disposed within the axle holes of the corresponding cycloid discs. Due to the eccentric cylinders, the eccentric direction of two cycloid discs is opposite to the eccentric direction of the other two cycloid discs. Consequently, it is not necessary to install an additional weight compensation device in the cycloid speed reducer to compensate the dynamic equilibrium. Moreover, the cycloid speed reducer can be assembled easily.

Abstract: A bearing assembly and a rotary shaft apparatus employing the same are provided. The bearing assembly is rotatably coupled with a first shaft and a second shaft. The first bearing housing includes a first annular recess having a first axial depth. The first bearing is connected with the first annular recess and the first shaft and has a first axial thickness. The second bearing housing includes a second annular recess having a second axial depth. The second bearing is connected with the first annular recess, the second annular recess and the second shaft and has a second axial thickness. The spacer is disposed between the first bearing and the second bearing and has a third axial thickness. The sum of the first axial thickness, the second axial thickness and the third axial thickness is greater than the sum of the first axial depth and the second axial depth.

Abstract: A cycloid speed reducer includes a weight element, an input shaft and a cycloid disc. The weight element is disposed within an accommodation space of the cycloid disc. An eccentric part is disposed on the input shaft. Since the length of the input shaft is reduced, the overall length of the cycloid speed reducer is shortened. Moreover, the mass center of the weight element and the mass center of the eccentric part and the cycloid disc are arranged along the same axial direction. That is, the line passing through the mass center of the weight element and the mass center of the eccentric part and the cycloid disc is perpendicular to the input shaft. Consequently, the efficacy of the dynamic balance of the cycloid speed reducer is enhanced.

Abstract: A speed reducing device includes a motor and a speed reducing mechanism. The speed reducing mechanism includes at least one roller assembly, a cycloid disc, at least one fixing disc and a positioning assembly. The roller assembly is disposed within a rotor portion of the motor. While the roller assembly is rotated with the rotor portion, the roller assembly is eccentrically revolved. The roller assembly includes a wheel disc and at least one roller. The cycloid disc includes a main body and at least one cycloid tooth structure. The cycloid tooth structure is protruded from an outer periphery of the main body and in contact with the corresponding roller. While the roller assembly is eccentrically revolved, the at least one cycloid tooth structure is pushed against the corresponding roller, so that the cycloid disc is correspondingly rotated.

Abstract: A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.

Abstract: A two-stage cycloid speed reducer comprises two rotating disc assemblies. Each rotating disc assembly comprises two cycloid discs. In other words, the cycloid speed reducer has four cycloid discs to be in contact with the corresponding rollers. Consequently, the load withstood by each cycloid disc is reduced. Since the cycloid speed reducer has stronger structural strength, the cycloid speed reducer can be applied to the high-load circumstance. Moreover, an eccentric assembly of the eccentric device includes a plurality of eccentric cylinders. The eccentric cylinders are disposed within the axle holes of the corresponding cycloid discs. Due to the eccentric cylinders, the eccentric direction of two cycloid discs is opposite to the eccentric direction of the other two cycloid discs. Consequently, it is not necessary to install an additional weight compensation device in the cycloid speed reducer to compensate the dynamic equilibrium. Moreover, the cycloid speed reducer can be assembled easily.