reducer

Abstract

The present application relates to a kind of reducers, the reducer of the present application has: the shell of outer diameter D;Multiple crankshafts;And gear carrier, it supports multiple the crankshafts respectively as can rotate, under the action of multiple the crankshafts, relative to the shell rotating movement.Multiple the crankshafts all have: multiple eccentric bodies, with diameter dc1;Crankshaft journal, with diameter dc2;n1 needle rollers, it is arranged around multiple the eccentric bodies, and with diameter size dr1;And n2 needle rollers, it is arranged around the crankshaft journal, and with diameter size dr2, satisfy relationship formula 5.5≤D / dc1≤7.0.

Description

Technical Field

[0001] This invention relates to a technology applicable to speed reducers. Background Technology

[0002] Patent document 1 discloses a speed reduction device, which includes: an external gear, an internal gear for internal meshing with the external gear, a housing provided with the internal gear, and a gear carrier that rotates relative to the housing.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-109264 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] There is a need for a speed reducer with high torsional stiffness and high damping characteristics.

[0008] Previously, tapered roller bearings were used in crankshaft journals, which made it impossible to increase the diameter of the crankshaft journals and increase the fill factor, making it difficult to achieve high rigidity and high damping in the reducer.

[0009] The present invention was made in view of the above circumstances in order to achieve the purpose of making the reducer more rigid and more damped.

[0010] Solution for solving the problem

[0011] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged around the eccentric body with n1 rollers; and rollers of diameter dr2 arranged around the crankshaft journal with n2 rollers, 5.5≤D / dc1≤7.0.

[0012] Here, the word "roller" corresponds to the word "roller needle".

[0013] In other words, a reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction of the imaginary circle, each crankshaft having a first external tooth; a plurality of external tooth members, each having a second external tooth meshing with the internal teeth of the housing, and performing eccentric motion under the action of the plurality of crankshafts; and a gear carrier supporting the plurality of crankshafts to be rotatable, and under the action of the plurality of crankshafts... The crankshafts rotate relative to the housing and each crankshaft has: a plurality of eccentric bodies corresponding to the plurality of external gear members and each having a diameter dc1; a crankshaft journal corresponding to the gear carrier and having a diameter dc2; n1 first needle rollers arranged around each of the plurality of eccentric bodies, each of the n1 first needle rollers having a diameter dr1; and n2 second needle rollers arranged around the crankshaft journal, each of the n2 second needle rollers having a diameter dr2, satisfying the relation 5.5≤D / dc1≤7.0.

[0014] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. This increases the number of contacts between the eccentric body and the needle rollers, reduces the load applied to a single needle roller, and improves the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0015] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0016] A speed reducer according to one embodiment of the present invention comprises: a housing having a cylindrical shape with an outer diameter of D1 and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter of dc1; a crankshaft journal having a diameter of dc2; rollers of diameter dr1 having n1 arranged around the eccentric body; and rollers of diameter dr2 having n2 arranged around the crankshaft journal, 4.5≤D1 / dc1≤6.0.

[0017] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0018] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0019] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged around the eccentric body with n1 rollers; and rollers of diameter dr2 arranged around the crankshaft journal with n2 rollers, 2.0≤D2 / dc1≤3.0.

[0020] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing, and the crankshaft is positioned away from the central axis of the reduction gear. That is, for the balance of the reduction gear, the crankshaft is set to be thicker and located on the outer side, thereby increasing the number of needle rollers arranged around the eccentric body. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation of the load applied to multiple needle rollers and setting the crankshaft to be thicker, rigidity can be improved.

[0021] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0022] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged with n1 rollers around the eccentric body; and rollers of diameter dr2 arranged with n2 rollers around the crankshaft journals, 6.0≤dc1 / dr1≤9.0.

[0023] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0024] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0025] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged around the eccentric body with n1 rollers; and rollers of diameter dr2 arranged around the crankshaft journal with n2 rollers, 6.0≤D / dc2≤7.5.

[0026] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be relatively large compared to the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0027] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0028] A speed reducer according to one embodiment of the present invention comprises: a housing having a cylindrical shape with an outer diameter D1 and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged with n1 around the eccentric body; and rollers of diameter dr2 arranged with n2 around the crankshaft journal, 5.0≤D1 / dc2≤6.5.

[0029] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be relatively large compared to the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0030] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0031] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged around the eccentric body with n1 rollers; and rollers of diameter dr2 arranged around the crankshaft journal with n2 rollers, 2.5≤D2 / dc2≤3.5.

[0032] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be larger than the cross-sectional area of ​​the housing, and the crankshaft is positioned away from the central axis of the reduction gear. That is, the crankshaft is set to be thicker for the balance of the reduction gear, and is located on the outer side, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and setting the crankshaft to be thicker, rigidity can be improved.

[0033] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0034] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged with n1 rollers around the eccentric body; and rollers of diameter dr2 arranged with n2 rollers around the crankshaft journal, 6.0≤dc2 / dr2≤9.0.

[0035] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be relatively large compared to the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0036] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0037] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged around the eccentric body with n1 rollers; and rollers of diameter dr2 arranged around the crankshaft journal with n2 rollers, 0.85≤dc2 / dc1≤1.0.

[0038] According to a reduction gear of the present invention, the cross-sectional area of ​​the eccentric body of the crankshaft and the cross-sectional area of ​​the crankshaft journal are set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is set to be thicker in terms of the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body and the crankshaft journal. At the same time, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. In addition, by reducing the deviation of the load applied to multiple needle rollers and setting the crankshaft to be thicker, the rigidity can be improved. Furthermore, the damping characteristics can be improved by setting the thickness of the eccentric body, the crankshaft journal, and the needle rollers within an appropriate range.

[0039] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0040] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged with n1 around the eccentric body; and rollers of diameter dr2 arranged with n2 around the crankshaft journal, 0.7≤n1·dr1 / π(dc1+dr1)≤0.9.

[0041] According to a reduction gear of the present invention, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is set to be thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. At the same time, the thickness and number of needle rollers can be set within an appropriate range, increasing the contact between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. In addition, by reducing the deviation of the load applied to multiple needle rollers and setting the crankshaft to be thicker, the rigidity can be improved.

[0042] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0043] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged with n1 around the eccentric body; and rollers of diameter dr2 arranged with n2 around the crankshaft journal, 15.3≤n1≤28.3.

[0044] According to a technical solution of the present invention, the reducer can set the number of needle rollers around the eccentric body of the crankshaft within an appropriate range, thereby increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reducer. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and simultaneously making the crankshaft thicker, rigidity can be improved.

[0045] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0046] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 having n1 arranged around the eccentric body; and rollers of diameter dr2 having n2 arranged around the crankshaft journal, 0.7≤n2·dr2 / π(dc2+dr2)≤0.9.

[0047] According to a reduction gear of the present invention, the cross-sectional area of ​​the crankshaft journal is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is set to be thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. At the same time, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. In addition, the deviation of the load applied to multiple needle rollers is reduced, and the thicker crankshaft is set, thereby improving rigidity.

[0048] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0049] A speed reducer according to one embodiment of the present invention comprises: a housing having an outer diameter D and having internal teeth; a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction, the plurality of crankshafts having external teeth; a plurality of external tooth members having external teeth that mesh with the internal teeth of the housing and undergo eccentric motion under the action of the crankshafts; and a gear carrier supporting the crankshafts so as to be rotatable and rotating relative to the housing under the action of the crankshafts, the crankshaft having: an eccentric body having a diameter dc1; a crankshaft journal having a diameter dc2; rollers of diameter dr1 arranged with n1 around the eccentric body; and rollers of diameter dr2 arranged with n2 around the crankshaft journal, 15.3≤n2≤28.3.

[0050] According to a technical solution of the present invention, the number of needle rollers disposed around the crankshaft journal can be set within an appropriate range, thereby increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reducer. Furthermore, it can reduce the deviation in load applied to multiple needle rollers, while simultaneously making the crankshaft thicker, thereby improving rigidity.

[0051] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0052] The reducer of one embodiment of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft comprising an eccentric body with a diameter dc1, wherein 5.5≤D / dc1≤7.0.

[0053] In other words, a reducer according to one embodiment of the present invention has: a housing with an outer diameter of D and internal teeth; and a plurality of crankshafts located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and separated from each other in the circumferential direction of the imaginary circle, each crankshaft including an eccentric body having a diameter dc1, satisfying the relation 5.5≤D / dc1≤7.0.

[0054] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. This increases the number of contacts between the eccentric body and the needle rollers, reduces the load applied to a single needle roller, and improves the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0055] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0056] The reducer of one embodiment of the present invention comprises: a housing having a cylindrical shape with an outer diameter D1 and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft comprising an eccentric body with a diameter dc1 and a crankshaft journal with a diameter dc2, wherein 4.5≤D1 / dc1≤6.0.

[0057] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0058] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0059] The reducer of one embodiment of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft comprising an eccentric body with a diameter dc1, wherein 2.0≤D2 / dc1≤3.0.

[0060] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing, and the crankshaft is positioned away from the central axis of the reduction gear. That is, for the balance of the reduction gear, the crankshaft is set to be thicker and located on the outer side, thereby increasing the number of needle rollers arranged around the eccentric body. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation of the load applied to multiple needle rollers and setting the crankshaft to be thicker, rigidity can be improved.

[0061] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0062] The reducer of one embodiment of the present invention comprises: a housing having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft comprising: an eccentric body having a diameter dc1; and rollers having a diameter dr1 arranged around the eccentric body, wherein 6.0 ≤ dc1 / dr1 ≤ 9.0.

[0063] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0064] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0065] The reducer of one embodiment of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter of D2 and concentric with the central axis of the housing, the crankshaft comprising: a crankshaft journal having a diameter of dc2; and n2 rollers having a diameter of dr2 arranged around the crankshaft journal, wherein 6.0≤D / dc2≤7.5.

[0066] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be relatively large compared to the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0067] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0068] The reducer of one embodiment of the present invention comprises: a housing having a cylindrical shape with an outer diameter D1 and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft including a crankshaft journal with a diameter dc2, 5.0≤D1 / dc2≤6.5.

[0069] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be relatively large compared to the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0070] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0071] The reducer of one embodiment of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft including a crankshaft journal with a diameter dc2, wherein 2.5≤D2 / dc2≤3.5.

[0072] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be larger than the cross-sectional area of ​​the housing, and the crankshaft is positioned away from the central axis of the reduction gear. That is, the crankshaft is set to be thicker for the balance of the reduction gear, and is located on the outer side, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and setting the crankshaft to be thicker, rigidity can be improved.

[0073] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0074] The reducer of one embodiment of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, the crankshaft comprising: a crankshaft journal having a diameter of dc2; and rollers having a diameter of dr2 arranged around the crankshaft journal, wherein 6.0 ≤ dc2 / dr2 ≤ 9.0.

[0075] According to a reduction gear of the present invention, when viewed axially from the housing, the cross-sectional area of ​​the crankshaft journal is set to be relatively large compared to the cross-sectional area of ​​the housing. That is, the crankshaft is made thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. Simultaneously, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and making the crankshaft thicker, rigidity can be improved.

[0076] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0077] The reducer of one technical solution of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and being concentric with the central axis of the housing, the crankshaft comprising: an eccentric body having a diameter of dc1; and a crankshaft journal having a diameter of dc2, 0.85≤dc2 / dc1≤1.0.

[0078] According to a reduction gear of the present invention, the cross-sectional area of ​​the eccentric body of the crankshaft and the cross-sectional area of ​​the crankshaft journal are set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is set to be thicker in terms of the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body and the crankshaft journal. At the same time, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the eccentric body and the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. In addition, by reducing the deviation of the load applied to multiple needle rollers and setting the crankshaft to be thicker, the rigidity can be improved. Furthermore, the damping characteristics can be improved by setting the thickness of the eccentric body, the crankshaft journal, and the needle rollers within an appropriate range.

[0079] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0080] The reducer of one embodiment of the present invention comprises: a housing with an outer diameter of D and internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing. The crankshaft includes: an eccentric body with a diameter of dc1; and rollers with a diameter of dr1, wherein n1 rollers are arranged around the eccentric body, and 0.7≤n1·dr1 / π(dc1+dr1)≤0.9.

[0081] According to a reduction gear of the present invention, the cross-sectional area of ​​the eccentric body of the crankshaft is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is set to be thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the eccentric body. At the same time, the thickness and number of needle rollers can be set within an appropriate range, increasing the contact between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. In addition, by reducing the deviation of the load applied to multiple needle rollers and setting the crankshaft to be thicker, the rigidity can be improved.

[0082] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0083] The reducer of one embodiment of the present invention comprises: a housing with an outer diameter of D and internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing. The crankshaft includes: an eccentric body with a diameter of dc1; and rollers with a diameter of dr1, wherein n1 rollers are arranged around the eccentric body, where 15.3 ≤ n1 ≤ 28.3.

[0084] According to a technical solution of the present invention, the reducer can set the number of needle rollers around the eccentric body of the crankshaft within an appropriate range, thereby increasing the number of contacts between the eccentric body and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reducer. Furthermore, by reducing the deviation in the load applied to multiple needle rollers and simultaneously making the crankshaft thicker, rigidity can be improved.

[0085] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0086] The reducer of one embodiment of the present invention comprises: a housing with an outer diameter of D and internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing. The crankshaft includes: a crankshaft journal with a diameter of dc2; and rollers with a diameter of dr2, of which n2 are arranged around the crankshaft journal, 0.7≤n2·dr2 / π(dc2+dr2)≤0.9.

[0087] According to a reduction gear of the present invention, the cross-sectional area of ​​the crankshaft journal is set to be larger than the cross-sectional area of ​​the housing. That is, the crankshaft is set to be thicker for the balance of the reduction gear, thereby increasing the number of needle rollers arranged around the crankshaft journal. At the same time, the thickness of the needle rollers can be set within an appropriate range, increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reduction gear. In addition, the deviation of the load applied to multiple needle rollers is reduced, and the thicker crankshaft is set, thereby improving rigidity.

[0088] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0089] The reducer of one embodiment of the present invention comprises: a housing having an outer diameter of D and having internal teeth; and a crankshaft located on the circumference of an imaginary circle having a diameter of D2 and concentric with the central axis of the housing, the crankshaft comprising: a crankshaft journal having a diameter of dc2; and rollers having a diameter of dr2, wherein n2 rollers are arranged around the crankshaft journal, 15.3≤n2≤28.3.

[0090] According to a technical solution of the present invention, the number of needle rollers disposed around the crankshaft journal can be set within an appropriate range, thereby increasing the number of contacts between the crankshaft journal and the needle rollers, reducing the load applied to a single needle roller, and improving the damping performance of the reducer. Furthermore, it can reduce the deviation in load applied to multiple needle rollers, while simultaneously making the crankshaft thicker, thereby improving rigidity.

[0091] That is, in the case of this reducer, the crankshaft is set to be thicker and the bearings are equipped with many small-diameter needle rollers, thereby increasing the number of physical contacts and improving rigidity and damping characteristics.

[0092] The effects of the invention

[0093] By employing this invention, the speed reducer can achieve the effects of high rigidity and high damping. Attached Figure Description

[0094] Figure 1This is a cross-sectional view along the crankshaft axis of the reducer according to the first embodiment of the present invention.

[0095] Figure 2 It is along Figure 1 A sectional view along line II-II.

[0096] Explanation of reference numerals in the attached figures

[0097] 100. Reducer; 200. Housing; 210. Outer cylinder (housing); 211. Outer cylinder; 212. Internal gear pin (internal gear); 215. Mounting flange; 216. Mounting hole; 220. Gear carrier (gear carrier); 221. Base; 222. End plate; 223. Pin; 224. Fixing bolt; 225. Base plate; 226. Column; 227. Threaded hole; 228. Reamed hole; 229. Through hole; 230. Main bearing; 300. Gear section (external gear component); 310. Gear; 320. Gear; 400. Crankshaft assembly Body; 410, crankshaft; 411, journal (crankshaft journal); 412, journal (crankshaft journal); 413, eccentric part (eccentric body); 414, eccentric part (eccentric body); 421-424, bearing; 430, transmission gear (external gear); 431-434, roller; D, outer diameter; D1, outer diameter; D2, diameter; D2h, radius; dc1, diameter; dc2, diameter; dr1, diameter dimension; dr2, diameter dimension; F0, central axis (main axis); F2, crankshaft axis (transmission axis); n1, number of pieces; n2, number of pieces. Detailed Implementation

[0098] Hereinafter, the reducer according to the first embodiment of the present invention will be described with reference to the accompanying drawings.

[0099] Figure 1 This is a cross-sectional view showing the speed reducer of this embodiment. Figure 2 It is along Figure 1 The figure shows a cross-sectional view of the reducer along line II-II. In the figure, reference numeral 100 indicates the reducer.

[0100] like Figure 1 , Figure 2 As shown, the reducer 100 of this embodiment includes: a housing 200, a gear section (external gear member) 300, and three crankshaft assemblies 400. The housing 200 houses the gear section 300 and the three crankshaft assemblies 400.

[0101] In this embodiment, the reducer 100 is an eccentric oscillating reducer.

[0102] The housing 200 includes: an outer cylinder (housing) 210, a gear carrier (gear carrier) 220, and two main bearings 230.

[0103] The outer cylinder portion 210 has internal teeth. The outer cylinder portion 210 has an outer diameter D. Furthermore, the outer cylinder portion 210 is formed in a cylindrical shape with an outer diameter D1.

[0104] The gear carrier 220 is disposed within the outer cylinder 210. The gear carrier 220 supports a plurality of crankshafts 410 (described later) so that they can rotate, and the gear carrier 220 rotates relative to the outer cylinder 210 under the action of the plurality of crankshafts 410. The crankshafts 410 cause the gear section 300 to oscillate.

[0105] Two main bearings 230 are respectively disposed between the outer cylinder portion 210 and the gear carrier portion 220. The two main bearings 230 enable relative rotational movement between the outer cylinder portion 210 and the gear carrier portion 220. The output portion of the reducer 100 in this embodiment is exemplified by one of the outer cylinder portion 210 and the gear carrier portion 220.

[0106] In the reducer 100 of this embodiment, a plurality of crankshafts 410 are respectively provided on a crankshaft assembly 400. The plurality of crankshafts 410 are located on the circumference of an imaginary circle (an arrangement circle for arranging the plurality of crankshafts 410) concentric with the central axis F0 of the outer cylinder portion 210, and are separated from each other in the circumferential direction of the imaginary circle. Each of the plurality of crankshafts 410 has a first external tooth. Here, the imaginary circle has... Figure 1 The circle with diameter indicated by reference numeral D2 in the attached figure.

[0107] Each gear section 300 (gears 310 and 320 described later) has a second external tooth that meshes with the internal teeth of the outer cylinder section 210. The second external tooth of the gear section 300 is different from the first external tooth of the crankshaft 410. The gear section 300 oscillates under the action of the multiple crankshafts 410, and performs eccentric motion under the action of the rotation of the multiple crankshafts 410.

[0108] exist Figure 1 The diagram shows the central axis (main axis) F0 of the reducer 100, which is defined as the rotational center axis of the two main bearings 230. With the outer cylinder portion 210 fixed, the gear carrier portion 220 rotates about the main axis F0. That is, one of the outer cylinder portion 210 and the gear carrier portion 220 can rotate relative to the other about the main axis F0.

[0109] A mounting flange 215 is provided around the outer periphery of the cylindrical outer cylinder portion 210. A plurality of mounting holes 216 are formed at intervals around the periphery of the mounting flange 215. The mounting flange 215 serves as a mating part, for example, when mounting the reducer 100.

[0110] The outer cylinder portion 210 includes an outer cylinder 211 and a plurality of internal toothed pins (internal teeth) 212. The outer cylinder 211 defines a cylindrical internal space for accommodating the gear carrier portion 220, the gear portion 300, and the crankshaft assembly 400. Each internal toothed pin 212 is a cylindrical member extending substantially parallel to the main axis F0. Each internal toothed pin 212 is embedded in a groove formed in the inner wall of the outer cylinder 211. Therefore, each internal toothed pin 212 is properly held by the outer cylinder 211.

[0111] Multiple internal toothed pins 212 are arranged at approximately constant intervals around the main axis F0. The semi-circular surface of each internal toothed pin 212 protrudes from the inner wall of the outer cylinder 211 toward the main axis F0. Therefore, the multiple internal toothed pins 212 function as internal teeth that mesh with the gear section 300.

[0112] The gear carrier portion 220 includes a base 221, an end plate portion 222, a locating pin 223, and a fixing bolt 224. The gear carrier portion 220 is integrally formed in a cylindrical shape. A through hole 229 concentric with the main axis F0 is formed in the gear carrier portion 220.

[0113] The base 221 includes a base plate portion 225 and three pillar portions 226. The three pillar portions 226 extend from the base plate portion 225 toward the end plate portion 222. A threaded hole 227 and a hinge hole 228 are formed on the top surface of each of the three pillar portions 226. A locating pin 223 is inserted into the hinge hole 228. As a result, the end plate portion 222 is positioned with high precision relative to the base 221. A fixing bolt 224 is threaded into the threaded hole 227. As a result, the end plate portion 222 is properly fixed to the base 221.

[0114] The gear portion 300 is disposed between the base plate portion 225 and the end plate portion 222. Three pillar portions 226 pass through the gear portion 300 and are connected to the end plate portion 222.

[0115] The gear section 300 includes two gears 310 and 320. Gear 310 is disposed between the base plate section 225 and gear 320. Gear 320 is disposed between the end plate section 222 and gear 310.

[0116] Gear 310 is approximately equal in shape and size to gear 320. Gears 310 and 320 mesh with the internal toothed pin 212 while rotating within the outer cylinder 211. Therefore, the centers of gears 310 and 320 rotate around the main axis F0.

[0117] The rotational phase of gear 310 is approximately 180° offset from the rotational phase of gear 320. During the period when gear 310 is engaged with half of the plurality of internal toothed pins 212 of the outer cylinder portion 210, gear 320 is engaged with the remaining half of the plurality of internal toothed pins 212. Therefore, gear portion 300 can rotate either outer cylinder portion 210 or gear carrier portion 220.

[0118] In this embodiment, the gear unit 300 includes two gears 310 and 320. Alternatively, more than two gears may be used as the gear unit. Furthermore, as an alternative, a single gear may be used as the gear unit.

[0119] Each of the three crankshaft assemblies 400 includes: a crankshaft 410, four bearings 421, 422, 423, and 424, and a transmission gear (external gear) 430. The transmission gear 430 can also be a general spur gear. For the reducer 100 of this embodiment, the transmission gear 430 is not limited to a specific type.

[0120] The transmission gear 430 is directly or indirectly subjected to the driving force generated by a drive source (e.g., a motor). The transmission path of the driving force from the drive source to the transmission gear 430 can be appropriately set according to the operating environment and conditions of the reducer 100. Therefore, this embodiment is not limited to a specific drive transmission path from the drive source to the transmission gear 430.

[0121] exist Figure 1 The image shows the crankshaft axis (transmission axis) F2. The transmission axis F2 is approximately parallel to the main axis F0. The crankshaft 410 rotates about the transmission axis F2. Figure 1 The notation “D2h” represents the distance between the transmission axis F2 and the main axis F0.

[0122] The crankshaft 410 includes two journals (crankshaft journals) 411 and 412 and two eccentric portions (eccentric bodies) 413 and 414. Journals 411 and 412 extend along the transmission axis F2. The central axis of journals 411 and 412 coincides with the transmission axis F2. Eccentric portions 413 and 414 are formed between journals 411 and 412. Eccentric portions 413 and 414 are eccentric from the transmission axis F2.

[0123] Eccentric portion 413 is positioned corresponding to gear 310, and eccentric portion 414 is positioned corresponding to gear 320. Eccentric portions 413 and 414 each have a diameter dc1.

[0124] Journal 412 is positioned corresponding to base 221 (gear carrier portion 220), and journal 411 is positioned corresponding to end plate portion 222 (gear carrier portion 220). Journals 411 and 412 each have a diameter dc2.

[0125] Journal 411 is inserted into bearing 421. Bearing 421 is disposed between journal 411 and end plate portion 222. Therefore, journal 411 is supported by end plate portion 222 and bearing 421. Journal 412 is inserted into bearing 422. Bearing 422 is disposed between journal 412 and base portion 221. Therefore, journal 412 is supported by base portion 221 and bearing 422.

[0126] In this embodiment, bearing 421 is configured as a needle roller bearing, with a plurality of needle rollers 431 (rollers) arranged around journal 411. Bearing 422 is configured as a needle roller bearing, with a plurality of needle rollers 432 (rollers) arranged around journal 412.

[0127] Needle roller 431 is equivalent to the second needle roller disposed around journal 411, and needle roller 432 is equivalent to the second needle roller disposed around journal 412. Needle rollers 431 and 432 each have a diameter dimension dr2. The number of needle rollers 431 and 432 is n2.

[0128] An eccentric portion 413 is inserted into a bearing 423. The bearing 423 is positioned between the eccentric portion 413 and the gear 310. An eccentric portion 414 is inserted into a bearing 424. The bearing 424 is positioned between the eccentric portion 414 and the gear 320.

[0129] In this embodiment, bearing 423 is configured as a needle roller bearing, with a plurality of needle rollers 433 (rollers) arranged around the eccentric portion 413. Bearing 424 is configured as a needle roller bearing, with a plurality of needle rollers 434 (rollers) arranged around the eccentric portion 414.

[0130] Needle roller 433 corresponds to the first needle roller disposed around eccentric body 413, and needle roller 434 corresponds to the first needle roller disposed around eccentric body 414. Needle rollers 433 and 434 each have a diameter dimension dr1. The number of needle rollers 433 and 434 is n1.

[0131] When driving force is input to the transmission gear 430, the crankshaft 410 rotates about the transmission axis F2. As a result, the eccentric portions 413 and 414 rotate eccentrically about the transmission axis F2. Gear 310, connected to the eccentric portion 413 by means of bearing 423, and gear 320, connected to the eccentric portion 414 by means of bearing 424, oscillate within the circular space defined by the outer cylinder portion 210. Gears 310 and 320 mesh with the internal toothed pin 212, thus causing relative rotational motion between the outer cylinder portion 210 and the gear carrier portion 220.

[0132] The dimensions and size relationships in the reducer 100 of this embodiment are set as follows.

[0133] The outer diameter D of the mounting flange 215

[0134] Outer diameter D1 of outer cylinder (shell) 210

[0135] The crankshaft axis (transmission axis) F2 is configured with a radius D2h, i.e., the diameter D2 of a circle concentric with the main axis F0.

[0136] The diameter dc1 of the eccentric parts 413 and 414

[0137] The diameter dc2 of journals 411 and 412

[0138] The diameter dimension dr1 of the needle rollers 433 and 434 around the eccentric parts 413 and 414

[0139] The diameter dimension dr2 of the needle rollers 431 and 432 around journals 411 and 412

[0140] 5.5≤D / dc1≤7.0…(Equation 1)

[0141] By setting it as in Formula 1, the crankshaft 410 is made thicker relative to the outermost diameter of the housing 210. That is, compared to conventionally used reducers, the crankshaft 410 is made thicker, and the rigidity of the crankshaft 410 is improved. At the same time, the diameter dc1 of the eccentric portions 413 and 414 is increased, and the diameter dr1 of the needle rollers is decreased, thereby increasing the number n1 of the needle rollers 433 arranged around the eccentric portion 413 and the needle rollers 434 arranged around the eccentric portion 414.

[0142] Here, the diameter ratio of the crankshaft 410 can be set to match the size of the reducer 100.

[0143] As a result, the number of line contacts between the needle rollers 433 and the eccentric portion 413 increases. By increasing the number of contacts between the needle rollers 433 and the eccentric portion 413, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 433 from the eccentric portion 413 can be reduced, suppressing the decrease in damping of the bearing 423.

[0144] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0145] Similarly, the number of line contacts between the needle rollers 434 and the eccentric portion 414 is increased. By increasing the number of contacts between the needle rollers 434 and the eccentric portion 414, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 434 from the eccentric portion 414 can be reduced, suppressing the decrease in damping of the bearing 424.

[0146] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0147] 4.5≤D1 / dc1≤6.0…(Equation 2)

[0148] By setting it as in Equation 2, the crankshaft 410 is made thicker relative to the housing 210. That is, compared to conventionally used reducers, the crankshaft 410 is made thicker, thus improving its rigidity. At the same time, the diameter dc1 of the eccentric portions 413 and 414 is increased, and the diameter dr1 of the needle rollers is decreased, thereby increasing the number n1 of the needle rollers 433 arranged around the eccentric portion 413 and the needle rollers 434 arranged around the eccentric portion 414.

[0149] As a result, the number of line contacts between the needle rollers 433 and the eccentric portion 413 increases. By increasing the number of contacts between the needle rollers 433 and the eccentric portion 413, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 433 from the eccentric portion 413 can be reduced, suppressing the decrease in damping of the bearing 423.

[0150] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0151] Similarly, the number of line contacts between the needle rollers 434 and the eccentric portion 414 is increased. By increasing the number of contacts between the needle rollers 434 and the eccentric portion 414, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 434 from the eccentric portion 414 can be reduced, suppressing the decrease in damping of the bearing 424.

[0152] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0153] 2.0≤D2 / dc1≤3.0…(Equation 3)

[0154] By setting it as in Equation 3, the crankshaft 410 is made thicker relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, compared to conventionally used reducers, the crankshaft 410 is made thicker, and the rigidity of the crankshaft 410 is improved. At the same time, the diameter dc1 of the eccentric portions 413 and 414 is increased, and the diameter dr1 of the needle rollers is decreased, thereby increasing the number n1 of the needle rollers 433 arranged around the eccentric portion 413 and the needle rollers 434 arranged around the eccentric portion 414. In addition, the crankshaft 410, needle rollers 433 and 434 and gear carrier 220 can be configured in a way that does not reduce their rigidity without excessively reducing the crankshaft 410, needle rollers 433 and 434 and gear carrier 220.

[0155] As a result, the number of line contacts between the needle rollers 433 and the eccentric portion 413 increases. By increasing the number of contacts between the needle rollers 433 and the eccentric portion 413, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 433 from the eccentric portion 413 can be reduced, suppressing the decrease in damping of the bearing 423.

[0156] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0157] Similarly, the number of line contacts between the needle rollers 434 and the eccentric portion 414 is increased. By increasing the number of contacts between the needle rollers 434 and the eccentric portion 414, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 434 from the eccentric portion 414 can be reduced, suppressing the decrease in damping of the bearing 424.

[0158] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0159] 6.0≤dc1 / dr1≤9.0…(Equation 4)

[0160] By setting it as in Formula 4, the crankshaft 410 is made thicker relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, by making the crankshaft 410 thicker, the rigidity of the crankshaft 410 is improved. At the same time, the thickness of the needle rollers 433 disposed around the eccentric portion 413 and the needle rollers 434 disposed around the eccentric portion 414 is set within a predetermined range relative to the diameter dc1 of the eccentric portions 413 and 414. As a result, the number n1 of needle rollers 433 and 434 is greater than that of conventionally used reducers. In addition, the crankshaft 410, needle rollers 433 and 434 and gear carrier 220 can be configured in a way that does not reduce their rigidity without excessively reducing the size of the crankshaft 410, needle rollers 433 and 434 and gear carrier 220.

[0161] As a result, the number of line contacts between the needle rollers 433 and the eccentric portion 413 increases. By increasing the number of contacts between the needle rollers 433 and the eccentric portion 413, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 433 from the eccentric portion 413 can be reduced, suppressing the decrease in damping of the bearing 423.

[0162] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0163] Similarly, the number of line contacts between the needle rollers 434 and the eccentric portion 414 is increased. By increasing the number of contacts between the needle rollers 434 and the eccentric portion 414, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 434 from the eccentric portion 414 can be reduced, suppressing the decrease in damping of the bearing 424.

[0164] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr1 becomes too small, reducing durability; therefore, this is not preferable.

[0165] 6.0≤D / dc2≤7.5…(Equation 5)

[0166] By setting it as in Formula 5, the crankshaft 410 is made thicker relative to the outermost diameter of the housing 210. That is, by making the crankshaft 410 thicker than conventionally used reducers, the rigidity of the crankshaft 410 is improved. At the same time, by increasing the diameter dc2 of the journals 411 and 412 and decreasing the diameter dr2 of the needle rollers, the number n2 of the needle rollers 431 arranged around the journal 411 and the needle rollers 432 arranged around the journal 412 is increased. Here, the diameter-to-size ratio of the crankshaft 410 can be set to match the size of the reducer 100.

[0167] As a result, the number of line contacts between the needle rollers 431 and the journal 411 increases. By increasing the number of contacts between the needle rollers 431 and the journal 411, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 431 from the journal 411 can be reduced, suppressing the decrease in damping of the bearing 421.

[0168] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0169] Similarly, the number of line contacts between the needle rollers 432 and the journal 412 is increased. By increasing the number of contacts between the needle rollers 432 and the journal 412, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 432 from the journal 412 can be reduced, suppressing the decrease in damping of the bearing 422.

[0170] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0171] 5.0≤D1 / dc2≤6.5…(Equation 6)

[0172] By setting it as in Formula 6, the crankshaft 410 is made thicker relative to the housing 210. That is, compared to conventionally used reducers, the crankshaft 410 is made thicker, thus improving its rigidity. At the same time, the diameter dc2 of the journals 411 and 412 is increased, and the diameter dr2 of the needle rollers is decreased, thereby increasing the number n2 of the needle rollers 431 arranged around the journal 411 and the needle rollers 432 arranged around the journal 412.

[0173] As a result, the number of line contacts between the needle rollers 431 and the journal 411 increases. By increasing the number of contacts between the needle rollers 431 and the journal 411, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 431 from the journal 411 can be reduced, suppressing the decrease in damping of the bearing 421.

[0174] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0175] Similarly, the number of line contacts between the needle rollers 432 and the journal 412 is increased. By increasing the number of contacts between the needle rollers 432 and the journal 412, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 432 from the journal 412 can be reduced, suppressing the decrease in damping of the bearing 422.

[0176] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0177] 2.5≤D² / dc²≤3.5…(Equation 7)

[0178] By setting it as in Equation 7, the crankshaft 410 is made thicker relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, compared to conventionally used reducers, the crankshaft 410 is made thicker, thereby improving its rigidity. At the same time, the diameter dc2 of the journals 411 and 412 is increased, and the diameter dr2 of the needle rollers is decreased, thereby increasing the number n2 of the needle rollers 431 arranged around the journal 411 and the needle rollers 432 arranged around the journal 412. In addition, the crankshaft 410, needle rollers 431 and 432, and gear carrier 220 can be configured in a way that does not reduce their rigidity without excessively reducing the size of the crankshaft 410, needle rollers 431 and 432, and gear carrier 220.

[0179] As a result, the number of line contacts between the needle rollers 431 and the journal 411 increases. By increasing the number of contacts between the needle rollers 431 and the journal 411, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 431 from the journal 411 can be reduced, suppressing the decrease in damping of the bearing 421.

[0180] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0181] Similarly, the number of line contacts between the needle rollers 432 and the journal 412 is increased. By increasing the number of contacts between the needle rollers 432 and the journal 412, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 432 from the journal 412 can be reduced, suppressing the decrease in damping of the bearing 422.

[0182] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0183] 6.0≤dc² / dr²≤9.0…(Equation 8)

[0184] By setting it as in Equation 8, the crankshaft 410 is made thicker relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, by making the crankshaft 410 thicker, the rigidity of the crankshaft 410 is improved. At the same time, the thickness of the needle rollers 431 disposed around the journal 411 and the needle rollers 432 disposed around the journal 412 are set within a predetermined range relative to the diameter dc2 of the journals 411 and 412. As a result, the number n2 of needle rollers 431 and 432 is greater than that of conventionally used reducers. In addition, the crankshaft 410, needle rollers 431 and 432 and gear carrier 220 can be configured in a way that does not reduce their rigidity without excessively reducing the size of the crankshaft 410, needle rollers 431 and 432 and gear carrier 220.

[0185] As a result, the number of line contacts between the needle rollers 431 and the journal 411 increases. By increasing the number of contacts between the needle rollers 431 and the journal 411, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 431 from the journal 411 can be reduced, suppressing the decrease in damping of the bearing 421.

[0186] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0187] Similarly, the number of line contacts between the needle rollers 432 and the journal 412 is increased. By increasing the number of contacts between the needle rollers 432 and the journal 412, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 432 from the journal 412 can be reduced, suppressing the decrease in damping of the bearing 422.

[0188] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, and the needle roller diameter dr2 becomes too small, reducing durability; therefore, this is not preferable.

[0189] 0.85≤dc2 / dc1≤1.0…(Equation 9)

[0190] By setting it as in Formula 9, the crankshaft 410 is made thicker relative to the housing 210, and this is done with the configuration of the crankshaft 410 taken into account. That is, by making the crankshaft 410 thicker, the rigidity of the crankshaft 410 is improved. At the same time, the balance between the thickness of the eccentric portions 413 and 414 and the thickness of the journals 411 and 412 is adjusted to optimize the load balance of the crankshaft 410. In addition, the relationship between the number and thickness of the needle rollers 433 and 434 and the needle rollers 431 and 432 arranged around the eccentric portions 413 and 414 and the journals 411 and 412 is set within a predetermined range. As a result, compared with the conventionally used reducer, the number n1 of needle rollers 433 and 434 and the number n2 of needle rollers 431 and 432 are optimized and increased. In addition, without excessively reducing the size of the crankshaft 410, needle rollers 431-434, or making the gear carrier 220 thin-walled, it is possible to configure them in a way that does not reduce their rigidity.

[0191] 0.7≤n1·dr1 / π(dc1+dr1)≤0.9…(Formula 10)

[0192] By setting it as in Formula 10, the ratio of the length occupied by the needle rollers 433 and 434 in the circumferential direction in the number n1 to the length around the eccentric portions 413 and 414, i.e., the occupancy rate of the needle rollers 433 and 434 in the eccentric portions 413 and 414, can be set within a predetermined range.

[0193] Therefore, the crankshaft 410 is set to be relatively thick relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, by setting the crankshaft 410 to be relatively thick, the rigidity of the crankshaft 410 is improved. At the same time, the thickness of the needle rollers 433 and 434 disposed around the eccentric portions 413 and 414 is set within a predetermined range relative to the thickness of the eccentric portions 413 and 414. As a result, the number n1 of needle rollers 433 and 434 is greater than that of conventionally used reducers. In addition, without excessively reducing the size of the crankshaft 410, the needle rollers 433 and 434, or making the gear carrier 220 thin-walled, it is possible to configure them in a way that does not reduce their rigidity.

[0194] As a result, the number of line contacts between the needle rollers 433 and the eccentric portion 413 increases. By increasing the number of contacts between the needle rollers 433 and the eccentric portion 413, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 433 from the eccentric portion 413 can be reduced, suppressing the decrease in damping of the bearing 423.

[0195] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​below this range. Conversely, if the value exceeds this range, the strength of the bearing retainer cannot be guaranteed, which is not preferable.

[0196] Similarly, the number of line contacts between the needle rollers 434 and the eccentric portion 414 is increased. By increasing the number of contacts between the needle rollers 434 and the eccentric portion 414, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 434 from the eccentric portion 414 can be reduced, suppressing the decrease in damping of the bearing 424.

[0197] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​below this range. Conversely, if the value exceeds this range, the strength of the bearing retainer cannot be guaranteed, which is not preferable.

[0198] 15.3≤n1≤28.3…(Equation 11)

[0199] By setting it as in Formula 11, the occupancy rate of the needle rollers 433 and 434 in the eccentric portions 413 and 414 can be set within a predetermined range as the number of needles n1.

[0200] Therefore, the crankshaft 410 is set to be relatively thick relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, by setting the crankshaft 410 to be relatively thick, the rigidity of the crankshaft 410 is improved. At the same time, the thickness of the needle rollers 433 and 434 disposed around the eccentric portions 413 and 414 is set within a predetermined range relative to the thickness of the eccentric portions 413 and 414. As a result, the number n1 of needle rollers 433 and 434 is greater than that of conventionally used reducers. In addition, without excessively reducing the size of the crankshaft 410, the needle rollers 433 and 434, or making the gear carrier 220 thin-walled, it is possible to configure them in a way that does not reduce their rigidity.

[0201] As a result, the number of line contacts between the needle rollers 433 and the eccentric portion 413 increases. By increasing the number of contacts between the needle rollers 433 and the eccentric portion 413, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 433 from the eccentric portion 413 can be reduced, suppressing the decrease in damping of the bearing 423.

[0202] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to a value smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, which is therefore undesirable.

[0203] Similarly, the number of line contacts between the needle rollers 434 and the eccentric portion 414 is increased. By increasing the number of contacts between the needle rollers 434 and the eccentric portion 414, the rigidity is improved. In addition, the unevenness caused by the load on each needle roller 434 from the eccentric portion 414 can be reduced, suppressing the decrease in damping of the bearing 424.

[0204] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to a value smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, which is therefore undesirable.

[0205] 0.7≤n2·dr2 / π(dc2+dr2)≤0.9…(Formula 12)

[0206] By setting it as in Formula 12, the ratio of the length occupied by the needle rollers 431 and 432 in the circumferential direction in a number n2 to the length around the journals 411 and 412, i.e., the occupancy rate of the needle rollers 431 and 432 on the journals 411 and 412, can be set within a predetermined range.

[0207] Therefore, the crankshaft 410 is set to be relatively thick relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, by setting the crankshaft 410 to be relatively thick, the rigidity of the crankshaft 410 is improved. At the same time, the thickness of the needle rollers 431 and 432 disposed around the journals 411 and 412 is set within a predetermined range relative to the thickness of the journals 411 and 412. As a result, the number n2 of needle rollers 431 and 432 is greater than that of conventionally used reducers. In addition, the crankshaft 410, needle rollers 431 and 432 can be configured in a way that does not reduce their rigidity without excessively reducing the size of the crankshaft 410, needle rollers 431 and 432 or making the gear carrier 220 thin-walled.

[0208] As a result, the number of line contacts between the needle rollers 431 and the journal 411 increases. By increasing the number of contacts between the needle rollers 431 and the journal 411, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 431 from the journal 411 can be reduced, suppressing the decrease in damping of the bearing 421.

[0209] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​below this range. Conversely, if the value exceeds this range, the strength of the bearing retainer cannot be guaranteed, which is not preferable.

[0210] Similarly, the number of line contacts between the needle rollers 432 and the journal 412 is increased. By increasing the number of contacts between the needle rollers 432 and the journal 412, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 432 from the journal 412 can be reduced, suppressing the decrease in damping of the bearing 422.

[0211] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to values ​​below this range. Conversely, if the value exceeds this range, the strength of the bearing retainer cannot be guaranteed, which is not preferable.

[0212] 15.3≤n²≤28.3…(Equation 13)

[0213] By setting it as in Formula 13, the occupancy of the needle rollers 431 and 432 on the journals 411 and 412 can be set within a predetermined range as the number of rollers n2. Therefore, the crankshaft 410 is set to be thicker relative to the housing 210, and the configuration of the crankshaft 410 is taken into account. That is, by setting the crankshaft 410 to be thicker, the rigidity of the crankshaft 410 is improved. At the same time, the thickness of the needle rollers 431 and 432 arranged around the journals 411 and 412 is set within a predetermined range relative to the thickness of the journals 411 and 412. Thus, the number of needle rollers 431 and 432 n2 is greater than that of conventionally used reducers. Furthermore, without excessively reducing the size of the crankshaft 410, the needle rollers 431 and 432, or making the gear carrier 220 thin-walled, it is possible to configure them in a way that does not reduce their rigidity.

[0214] As a result, the number of line contacts between the needle rollers 431 and the journal 411 increases. By increasing the number of contacts between the needle rollers 431 and the journal 411, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 431 from the journal 411 can be reduced, suppressing the decrease in damping of the bearing 421.

[0215] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to a value smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, which is therefore undesirable.

[0216] Similarly, the number of line contacts between the needle rollers 432 and the journal 412 is increased. By increasing the number of contacts between the needle rollers 432 and the journal 412, rigidity is improved. In addition, the unevenness caused by the load on each needle roller 432 from the journal 412 can be reduced, suppressing the decrease in damping of the bearing 422.

[0217] Furthermore, by setting the value within the aforementioned range, torsional stiffness can be improved compared to a value smaller than this range. Conversely, if the value is larger than this range, the through-hole 229 cannot achieve the required diameter, which is therefore undesirable.

[0218] In the case of the reducer 100 of this embodiment, the crankshaft 410 is set to be relatively thick, thereby improving rigidity. The needle rollers 431 to 434 are set to a predetermined thickness, and the number of rollers n1 and n2 is set to be relatively large. As a result, the load unevenness at the needle rollers 431 to 434 can be reduced to correspond with the size of the reducer 100, thus preventing a decrease in damping. In this way, durability is maintained while making it highly rigid and highly damped.

[0219] Furthermore, in this embodiment, the rigidity and damping characteristics of the reducer are improved, thus helping to suppress vibrations during acceleration and cessation of motion in applications such as robotics. Additionally, the increased internal friction of the reducer also contributes to improved controllability.

[0220] The principles of the various implementation methods described above can also be combined to adapt to the requirements of the speed reducer.

[0221] Industrial availability

[0222] As an example of the application of the present invention, all gear devices having crankshafts and cylindrical needle roller bearings can be cited.

Claims

1. A speed reducer, wherein, This reducer has the following features: A shell having an outermost diameter of D and internal teeth, the shell being a cylindrical shape with an outer diameter D1; Multiple crankshafts are located on the circumference of an imaginary circle having a diameter D2 and concentric with the central axis of the housing, and are separated from each other in the circumferential direction; the multiple crankshafts have external teeth. Multiple external gear members, each having external teeth that mesh with the internal teeth of the housing, and undergoing eccentric motion under the action of the crankshaft; and A gear carrier that supports the crankshaft so that it can rotate and, under the action of the crankshaft, rotates relative to the housing. The crankshaft has: An eccentric body with a diameter of dc1; Crankshaft journal, with a diameter of dc2; Rollers with a diameter of dr1, having n1 rollers arranged around the eccentric body; and There are n2 rollers with a diameter of dr2 arranged around the crankshaft journal. Set to the following range: 5.5≤D / dc1≤7.0 4.5≤D1 / dc1≤6.0, 2.0≤D² / dc¹≤3.0 6.0≤dc1 / dr1≤9.0, 6.0≤D / dc²≤7.5 5.0≤D1 / dc2≤6.5, 2.5≤D² / dc²≤3.5 6.0≤dc² / dr²≤9.0 0.85≤dc2 / dc1≤1.0 0.7≤n1·dr1 / π(dc1+dr1)≤0.9, 15.3≤n1≤28.3， 0.7≤n2·dr2 / π(dc2+dr2)≤0.9, 15.3≤n2≤28.3， As a result, torsional rigidity is improved compared to cases outside the range, reducing unevenness caused by the load on each roller from the eccentric body.

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