GEAR SUPPORT STRUCTURE

To suppress a weight increase and a cost increase while suppressing uneven contact of the first gear and the second gear that may be caused by inclination of the first axis due to a mesh reactive force.SOLUTION: A lubrication hole 58 is provided in a support wall portion 18w that supports a first-b bearing 34 and rigidity of the support wall portion 18w is partially reduced, such that, when a mesh reactive force Fr between a first gear 12 and a second gear 14 is applied to a first shaft 22, the first-b bearing 34 far from the first gear 12 deforms in a direction of the engagement reactive force Fr more easily than a first-a bearing 32 close to the first gear 12. Thus, a displacement amount at the side of the first-b bearing 34 in a case where the mesh reactive force Fr is applied to the first shaft 22 is increased, and the inclination of the first shaft S1 caused by application of the great mesh reactive force Fr to the side of the first-a bearing 32 is suppressed. Accordingly, uneven contact between the first gear 12 and the second gear 14 due to inclination of the first shaft S1 is reduced, thereby the durability of the first gear 12 and the second gear 14 increases.SELECTED DRAWING: Figure 3 【課題】重量増やコスト増を抑制しつつ噛合い反力に起因する第１軸線の傾斜に伴って第１歯車と第２歯車とが偏当たりすることを抑制する。【解決手段】第１歯車１２と第２歯車１４との噛合い反力Ｆｒが第１軸２２に加えられた場合に、第１歯車１２から遠い第１ｂ軸受３４が第１歯車１２に近い第１ａ軸受３２に比較して噛合い反力Ｆｒの方向へ変位し易くなるように、第１ｂ軸受３４を保持している支持壁部１８ｗに潤滑穴５８が設けられ、その支持壁部１８ｗの剛性が部分的に低下させられている。このため、第１軸２２に噛合い反力Ｆｒが加えられた場合の第１ｂ軸受３４側の変位量が増大させられ、第１ａ軸受３２側に大きな噛合い反力Ｆｒが加えられることに伴う第１軸線Ｓ１の傾斜が抑制されて、第１軸線Ｓ１の傾斜に起因する第１歯車１２と第２歯車１４との偏当たりが軽減され、第１歯車１２および第２歯車１４の耐久性が向上する。【選択図】図３