Power transmission device and power unit equipped with same
A power transmission device includes a first gear, a second gear meshing with the first gear, a third gear that rotates integrally with the second gear, a fourth gear meshing with the third gear, a housing accommodating the first gear, the second gear, the third gear, and the fourth gear, and a plate member mounted in the housing. A lubricating liquid is stored in the housing so that a part of the second gear and a part of the fourth gear are immersed therein. The plate member includes a catch tank arranged adjacent to the first gear, and a tray extending from the catch tank along the second gear into the lubricating liquid. The catch tank receives the lubricating liquid drawn up by the fourth gear and guides the lubricating liquid to the meshing portion between the first gear and the second gear.
1. A power transmission device comprising:
a first gear;
a second gear meshing with the first gear;
a third gear that rotates integrally with the second gear;
a fourth gear meshing with the third gear;
a housing accommodating the first gear, the second gear, the third gear, and the fourth gear; and
a plate member mounted in the housing, wherein:
a lubricating liquid is stored in the housing such that a part of the second gear and a part of the fourth gear are immersed therein;
the plate member includes a catch tank arranged adjacent to the first gear, and a tray extending from the catch tank along the second gear into the lubricating liquid; and
the catch tank is configured to receive the lubricating liquid drawn up by the fourth gear and guide the lubricating liquid to a meshing portion between the first gear and the second gear.
2. The power transmission device according to claim 1 , wherein:
the fourth gear is located on one side with respect to the meshing portion between the first gear and the second gear in a horizontal direction; and
the plate member is adjacent to the meshing portion between the first gear and the second gear from another side in the horizontal direction.
3. The power transmission device according to claim 1 , wherein the catch tank includes,
a first catch tank located above the first gear and receiving the lubricating liquid drawn up by the fourth gear, and
a second catch tank located below the first gear and guiding the lubricating liquid supplied from the first catch tank to the meshing portion.
4. The power transmission device according to claim 3 , wherein the first catch tank has a first supply hole used to supply the lubricating liquid to the second catch tank.
5. The power transmission device according to claim 4 , wherein the first supply hole is located directly above the first gear.
6. The power transmission device according to claim 4 , wherein:
the first catch tank has a first compartment, a second compartment, and a partition wall that partially isolates the first compartment and the second compartment; and
the first supply hole is provided in the second compartment.
7. The power transmission device according to claim 3 , wherein the first catch tank further includes a second supply hole used to supply the lubricating liquid to a bearing supporting the first gear.
8. The power transmission device according to claim 3 , wherein the second catch tank has a shape open toward the meshing portion.
9. The power transmission device according to claim 3 , wherein:
the catch tank further includes a vertical wall extending between the first catch tank and the second catch tank; and
the vertical wall faces an outer peripheral surface of the first gear.
10. The power transmission device according to claim 3 , wherein the tray extends in an arc shape from the second catch tank along an outer peripheral surface of the second gear.
11. A power unit comprising:
the power transmission device of claim 1 ; and
an electric motor driving the first gear of the power transmission device.
12. The power unit according to claim 11 , wherein the fourth gear is a ring gear of a differential unit.