The present invention relates to the technical field of transmission, more particularly to a planetary gear transmission box.
As automobiles develop continuously toward intelligence and comfort, electric tailgates have become a trend, and more and more cars have begun to use electric tailgates. Generally, the motor drives the gearbox and then drives the tailgate to open or close.
This type of gearbox is designed with a low transmission ratio, usually lower than 25, so it transmits a low torque, and the output torque is generally less than 5 Nm. Since it transmits a small torque and has low requirements for the strength of the sun gear, the sun gear of at least one stage of planetary gear train can be produced from plastic. In addition, since this type of gearbox has a low transmission ratio, symmetrical gearboxes are usually used.
Therefore, this type of gearbox has the defects of low torque transmission and high cost. In addition, since two gearboxes have to be arranged, a large space will be occupied.
To solve the above technical problem to a certain extent, the present invention proposes the following technical solutions:
A planetary gear transmission box, comprising a housing portion, a first planetary gear transmission stage, and a second planetary gear transmission stage, wherein the first planetary gear transmission stage comprises a first sun gear, a first planetary carrier, and a first ring gear; the second planetary gear transmission stage comprises a second sun gear, a second planetary carrier, and a second ring gear; the first sun gear is connected to an external input element, the first planetary carrier is connected to the second sun gear, and the second planetary carrier is connected to an output element; an transmission ratio of the gear transmission box is greater than 25.
A planetary gear transmission box, comprising a housing portion, a first planetary gear transmission stage, and a second planetary gear transmission stage, wherein the first planetary gear transmission stage comprises a first sun gear, a first planetary carrier, and a first ring gear; the second planetary gear transmission stage comprises a second sun gear, a second planetary carrier, and a second ring gear; the first sun gear is connected to an external input element, the first planetary carrier is connected to the second sun gear, and the second planetary carrier is connected to an output element; the second planetary carrier is directly supported on the box body.
According to the above two technical solutions, the present invention redesigns the transmission ratio of the gearbox, making it greater than or equal to 25, preferably between 25-30, so as to increase the locked rotor torque of the gearbox. In addition, the output rotation speed decreases due to the increase of the transmission ratio, so the bearing member can be omitted at the output end.
Further, material of the second sun gear is metal.
Further, the housing portion comprises an intermediate housing provided with a radially and inwardly extending support portion, and the first planetary carrier is supported by the support portion.
Further, the housing portion further comprises a first end cover and a second end cover.
Further, a bearing is provided in a central through hole of the first end cover.
Further, a gasket is provided between the first end cover and a planetary gear disposed on the first planetary carrier.
Other specific features and advantages will be clearly shown in the following description in conjunction with the accompanying drawings, and the description is given as a rough rather than limiting guide, in which
All the drawings are only schematic and are not necessarily drawn to scale. In addition, only those parts necessary to illustrate the invention are shown, and other parts are omitted or only mentioned. That is, in addition to the components shown in the drawings, the invention may also include other components.
The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.
Referring to
The transmission components include two-stage transmission devices. Specifically, the first transmission stage is composed of a first sun gear 3, a first planetary carrier 5, and a first ring gear formed on the inner side of the gearbox intermediate housing 4. The power input by the electric motor is transmitted to the first sun gear 3, then to the first planetary carrier 5 via the planetary gear, and then to the second transmission stage.
The second transmission stage includes a second sun gear, a second ring gear 6 and a second planetary carrier 7. The second ring gear 6 is fixedly arranged on the gearbox intermediate housing 4. As can be seen from
As can be seen from
In addition, as a preferred embodiment, lubricating oil is arranged between the second planetary carrier 7 and the second end cover 8 to further reduce the wear therebetween.
It can also be seen from
As another preferred embodiment of the present invention, referring to
The present invention redesigns the transmission ratio of the gearbox, making it greater than or equal to 25, preferably between 25-30, so as to increase the locked rotor torque of the gearbox, thus making it greater than 5.5 Nm. Accordingly, due to the increase of the torque, in order to increase the strength of structural members, the second sun gear is made of metal materials. Of course, the first sun gear, the first planetary carrier and the second planetary carrier can also be made of metal materials. In addition, the output rotation speed decreases due to the increase of the transmission ratio, so the bearing member can be omitted at the output end.
The present invention has been clearly and completely described with reference to the above schematic embodiments. Those skilled in the art should understand that various other embodiments can be envisaged by modifying the disclosed technical solution without departing from the spirit and scope of the present invention. These embodiments should be understood to fall within the scope of the present invention determined by its claims and any of its equivalent technical solutions.
Number | Date | Country | Kind |
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201910889607.2 | Sep 2019 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2020/113242 | 9/3/2020 | WO |