Speed reducer and motor with speed reducer
A speed reducer includes a casing, a crankshaft, and a speed reducer main body. The crankshaft has a rotation support part rotatably supported by the casing and an eccentric part eccentric with respect to the rotation support part. The speed reducer main body has an engagement part engaged with an outer circumferential surface of the eccentric part, decelerates rocking rotation of the eccentric part received by the engagement part, and outputs the decelerated rotation to outside. The crankshaft is provided with a flange part protruding to an outward side in a radial direction from an end part of the rotation support part on the eccentric part side and abutting an end surface of the engagement part in an axial direction. The flange part is formed such that a center thereof coincides with a center of the eccentric part in a direction orthogonal to the axial direction.
1. A speed reducer comprising:
a casing;
a crankshaft having a rotation support part rotatably supported by the casing and an eccentric part eccentric with respect to the rotation support part, and rotating in response to a rotation force from outside; and
a speed reducer main body having an engagement part engaged with an outer circumferential surface of the eccentric part, decelerating rocking rotation of the eccentric part received by the engagement part, and outputting the decelerated rotation to outside,
wherein the crankshaft is provided with a flange part protruding to an outward side in a radial direction from an end part of the rotation support part on the eccentric part side and abutting an end surface of the engagement part in an axial direction,
the flange part is formed such that a center thereof in a direction orthogonal to the axial direction coincides with a center of the eccentric part in a direction orthogonal to the axial direction,
the rotation support part is rotatably supported by the casing via a rotation support bearing,
the rotation support bearing is engaged with an outer circumferential surface of the rotation support part and abuts directly on an end surface of the flange part,
an outer diameter of the rotation support part is larger than an outer diameter of the eccentric part, and an outer diameter of the rotation support bearing is larger than an outer diameter of the engagement part.
2. The speed reducer according to claim 1 ,
wherein the flange part is formed in an annular shape having a uniform clearance from the outer circumferential surface to the eccentric part in a circumferential direction.
3. A motor with a speed reducer comprising:
the speed reducer according to claim 2 ; and
a motor part joined to the crankshaft of the speed reducer.
4. The speed reducer according to claim 1 ,
wherein the speed reducer main body includes
a bearing serving as the engagement part,
a rocking gear rotatably supported by the eccentric part of the crankshaft via the bearing, and having first internal teeth and first external teeth,
a fixed gear fixed to the casing, meshed with the first external teeth of the rocking gear, and having second internal teeth concentric with respect to a center axis of the rotation support part of the crankshaft, and
an output gear meshed with the first internal teeth of the rocking gear, and having second external teeth concentric with respect to the center axis.
5. A motor with a speed reducer comprising:
the speed reducer according to claim 4 ; and
a motor part joined to the crankshaft of the speed reducer.
6. A motor with a speed reducer comprising:
the speed reducer according to claim 1 ; and
a motor part joined to the crankshaft of the speed reducer.