Speed reducer casing, speed reducer, and method of manufacturing speed reducer casing
A speed reducer casing of the present invention has inner teeth on an inner periphery thereof. The speed reducer casing includes an inner tooth portion and a casing body portion, the inner tooth portion including the inner teeth, the casing body portion supporting the inner tooth portion. The inner tooth portion is formed of a material having a higher slidability than the casing body portion. The casing body portion is formed of a material having a higher hardness than the inner tooth portion.
1. A speed reducer casing having inner teeth on an inner periphery thereof, the speed reducer casing comprising:
an inner tooth portion including the inner teeth; and
a casing body portion supporting the inner tooth portion,
wherein a material forming the inner tooth portion is different from a material forming the casing body portion,
the material forming the inner tooth portion has a higher slidability than the material forming the casing body portion, and
wherein the material forming the casing body portion has a higher hardness than the material forming the inner tooth portion.
2. The speed reducer casing of claim 1 , wherein the casing body portion is formed of a material having a higher melting point than the inner tooth portion.
3. The speed reducer casing of claim 1 , wherein the casing body portion has such a tubular shape as to cover at least a radially outer region of the inner tooth portion.
4. The speed reducer casing of claim 3 , wherein the inner teeth of the inner tooth portion are formed of pin grooves retaining therein columnar inner tooth pins so as to be slidable.
5. A speed reducer comprising:
the speed reducer casing of claim 1 ; and
a speed reduction mechanism disposed inside the speed reducer casing.
6. The speed reducer casing of claim 1 ,
wherein the casing body portion is formed of a light metal having a high specific strength.
7. The speed reducer casing of claim 6 ,
wherein the casing body portion is formed of an aluminum alloy.
8. The speed reducer casing of claim 6 ,
wherein the inner tooth portion is formed of a hard resin.
9. The speed reducer casing of claim 8 ,
wherein the inner tooth portion is formed of an engineering plastic.
10. The speed reducer casing of claim 7 ,
wherein the inner tooth portion is formed of a hard resin.
11. The speed reducer casing of claim 10 ,
wherein the inner tooth portion is formed of an engineering plastic.
12. The speed reducer casing of claim 1 ,
wherein the inner tooth portion is formed of a hard resin.
13. The speed reducer casing of claim 12 ,
wherein the inner tooth portion is formed of an engineering plastic.
14. A method of manufacturing a speed reducer casing having inner teeth on an inner periphery thereof,
wherein the speed reducer casing includes an inner tooth portion and a casing body portion, the inner tooth portion including the inner teeth, the casing body portion supporting the inner tooth portion, a material forming the inner tooth portion being different from a material forming the casing body portion, the material forming the inner tooth portion having a higher slidability than the material forming the casing body portion, and the material forming the casing body portion having a higher hardness than the material forming the inner tooth portion,
the method comprises:
forming the casing body portion first; and
setting the casing body portion in a mold and forming the inner tooth portion by injection molding.