A transmission, comprising a box body with an inner cavity and a gear set and an oil supply device that are accommodated in the box body, wherein an oil sump carrying lubricating oil is disposed at the bottom of the inner cavity; the oil supply device is fastened on a side that is of the gear set and that is away from the oil sump, the oil supply device comprises a sealing chamber and an oil collection tank that are fastened to each other, and the oil collection tank is located above the sealing chamber; an oil inlet port and at least one oil spray pipe are disposed for the sealing chamber, and the at least one oil spray pipe extends in different directions; and the sealing chamber is configured to: receive the lubricating oil that is in the oil sump and that is transported from the oil inlet port, and spray the lubricating oil to at least one to-be-lubricated part of the gear set through the at least one oil spray pipe; and the oil collection tank has an upper opening, the oil collection tank is configured to: when the gear set rotates, receive, by using the upper opening, the lubricating oil that is in the oil sump and that is stirred and transported by the gear set, at least one oil transport tank is further disposed for the oil collection tank, a quantity of oil transport tanks is the same as a quantity of oil spray pipes, and any oil transport tank is disposed corresponding to one oil spray pipe, and is configured to lubricate a same to-be-lubricated part together with the corresponding oil spray pipe, wherein the transmission further comprises an oil transport component, the oil transport component comprises an oil transport pipeline and an oil transport pump, one end of the oil transport pipeline is connected to the oil inlet port of the oil supply device, the other end of the oil transport pipeline is connected to the oil sump, and the oil transport pump is configured to pump the lubricating oil in the oil sump into the sealing chamber through the oil transport pipeline. an oil sump carrying lubricating oil is disposed at the bottom of the inner cavity; the oil supply device is fastened on a side that is of the gear set and that is away from the oil sump, the oil supply device comprises a sealing chamber and an oil collection tank that are fastened to each other, and the oil collection tank is located above the sealing chamber; an oil inlet port and at least one oil spray pipe are disposed for the sealing chamber, and the at least one oil spray pipe extends in different directions; and the sealing chamber is configured to: receive the lubricating oil that is in the oil sump and that is transported from the oil inlet port, and spray the lubricating oil to at least one to-be-lubricated part of the gear set through the at least one oil spray pipe; and the oil collection tank has an upper opening, the oil collection tank is configured to: when the gear set rotates, receive, by using the upper opening, the lubricating oil that is in the oil sump and that is stirred and transported by the gear set, at least one oil transport tank is further disposed for the oil collection tank, a quantity of oil transport tanks is the same as a quantity of oil spray pipes, and any oil transport tank is disposed corresponding to one oil spray pipe, and is configured to lubricate a same to-be-lubricated part together with the corresponding oil spray pipe, wherein the transmission further comprises an oil transport component, the oil transport component comprises an oil transport pipeline and an oil transport pump, one end of the oil transport pipeline is connected to the oil inlet port of the oil supply device, the other end of the oil transport pipeline is connected to the oil sump, and the oil transport pump is configured to pump the lubricating oil in the oil sump into the sealing chamber through the oil transport pipeline.