Multi stage transmission for vehicle

The present application claims priority to Korean Patent Application No. 10-2015-0129687, filed Sep. 14, 2015, the entire contents of which is incorporated herein for all purposes by this reference.

The present invention relates to a multi stage transmission for a vehicle, and more particularly, to a technology capable of improving fuel efficiency of a vehicle by implementing shifting stages as many as possible by the number of components as small as possible and a simple configuration.

Recently, a rise in an oil price has become a factor allowing automobile manufacturers throughout the world to enter into unlimited competition toward fuel efficiency improvement, and in the case of an engine, an effort to improve fuel efficiency and decrease a weight through a technology such as downsizing, or the like, has been conducted.

Meanwhile, among methods of improving fuel efficiency that may be made by a transmission mounted in a vehicle, there is a method of allowing an engine to be driven at a more efficient driving point through a multi stage transmission to ultimately improve fuel efficiency.

In addition, the multi stage transmission as described above may allow the engine to be driven in a relatively low revolution per minute (RPM) band to further improve silence of the vehicle.

However, as shifting stages of the transmission are increased, the number of internal components configuring the transmission is increased, such that a mounting feature and transfer efficiency may be deteriorated and a cost and a weight may be increased. Therefore, in order to maximize a fuel efficiency improving effect through the multi stage transmission, it is important to devise a transmission structure capable of deriving maximum efficiency by a small number of components and a comparatively simple configuration.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Various aspects of the present invention are directed to providing a multi stage transmission for a vehicle capable of maximizing fuel efficiency improvement of the vehicle through driving at an optimal driving point of an engine and improving silence of the vehicle through more silent driving of the engine by implementing at least forward nine stages and reverse one stage or more by a comparatively small number of components and a simple configuration.

According to an exemplary embodiment of the present invention, there is provided a multi stage transmission for a vehicle, including: an input shaft and an output shaft; a first planetary gear device, a second planetary gear device, and a third planetary gear device provided to transfer a torque between the input shaft and the output shaft and each including three rotating elements; and at least six shifting elements connected to the rotating elements of the first to third planetary gear devices, in which the first planetary gear device may have a first rotating element which is permanently connected to the input shaft and is variably connected to a third rotating element of the third planetary gear device, a second rotating element which is fixedly installed by any one of the shifting elements and variably connected to the third rotating element of the third planetary gear device, and a third rotating element which is variably connected to a first rotating element of the second planetary gear device and permanently connected to a first rotating element of the third planetary gear device, and the second planetary gear device may have a first rotating element which is fixedly installed by the other one of the shifting elements and variably connected to a first rotating element of the third planetary gear device, a second rotating element which is permanently connected to the output shaft and variably connected to the first rotating element of the third planetary gear device, and a third rotating element which is permanently connected to a second rotating element of the third planetary gear device.

The first planetary gear device, the second planetary gear device, and the third planetary gear device may be sequentially disposed along a rotating shaft direction of the input shaft and the output shaft.

The first planetary gear device and the second planetary gear device may be configured as a single pinion simple planetary gear device and the third planetary gear device may be configured as a double pinion simple planetary gear device.

The second rotating element of the first planetary gear device may be fixedly installed in a transmission case by a first brake among the shifting elements, the first rotating element of the second planetary gear device may be fixedly installed in the transmission case by a second brake among the shifting elements, and the rest of the shifting elements may be configured to form variable connection structures between the rotating elements of the planetary gear devices.

A first clutch among the shifting elements may form a variable connection structure between the first rotating element of the first planetary gear device and the third rotating element of the third planetary gear device; a third clutch among the shifting elements may form a variable connection structure between the second rotating element of the first planetary gear device and the third rotating element of the third planetary gear device; a fourth clutch among the shifting elements may form a variable connection structure between the first rotating element of the second planetary gear device and the first rotating element of the third planetary gear device; and a second clutch among the shifting elements may form a variable connection structure between the second rotating element of the second planetary gear device and the first rotating element of the third planetary gear device.

According to another exemplary embodiment of the present invention, there is provided a multi stage transmission for a vehicle, including: a first planetary gear device, a second planetary gear device, and a third planetary gear device each having three rotating elements; six shifting elements configured so as to variably provide a frictional force; and eight rotating shafts connected to the rotating elements of the planetary gear devices, wherein a first rotating shaft is an input shaft directly connected to a first rotating element of the first planetary gear device, a second rotating shaft is directly connected to a second rotating element of the first planetary gear device, a third rotating shaft is directly connected to a third rotating element of the first planetary gear device and a first rotating element of the third planetary gear device, a fourth rotating shaft is directly connected to a third rotating element of the third planetary gear device, a fifth rotating shaft is directly connected to a first rotating element of the second planetary gear device, a sixth rotating shaft is directly connected to a third rotating element of the second planetary gear device and a second rotating element of the third planetary gear device, a seventh rotating shaft is an output shaft directly connected to a second rotating element of the second planetary gear device, and a first clutch among the six shifting elements is installed between the first rotating shaft and the fourth rotating shaft, a second clutch is installed between the third rotating shaft and the seventh rotating shaft, a third clutch is installed between the second rotating shaft and the fourth rotating shaft, a fourth clutch is installed between the third rotating shaft and the fifth rotating shaft, a first brake is installed between the second rotating shaft and a transmission case, and a second brake is installed between the fifth rotating shaft and the transmission case.

The first planetary gear device, the second planetary gear device, and the third planetary gear device may be sequentially disposed along a rotating shaft direction of the input shaft and the output shaft.

The first planetary gear device and the second planetary gear device may be configured as a single pinion simple planetary gear device and the third planetary gear device may be configured as a double pinion simple planetary gear device.

The first clutch may be installed to variably connect between the first rotating element of the first planetary gear device and the third rotating element of the third planetary gear device, the second clutch may be installed to variably connect between the second rotating element of the second planetary gear device and the first rotating element of the third planetary gear device, the third clutch may be installed to variably connect between the second rotating element of the first planetary gear device and the third rotating element of the third planetary gear device, and the fourth clutch may be installed to variably connect between the first rotating element of the second planetary gear device and the first rotating element of the third planetary gear device.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

FIG. 1 is a configuration diagram showing a configuration of a multi stage transmission for a vehicle according to an exemplary embodiment of the present invention.

FIG. 2 is a table showing operation modes of the multi stage transmission for a vehicle of FIG. 1 .

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1 , a multi stage transmission for a vehicle according to an exemplary embodiment of the present invention is configured to include an input shaft IN and an output shaft OUT, a first planetary gear device PG 1 , a second planetary gear device PG 2 , and a third planetary gear device PG 3 provided to transfer a torque between the input shaft IN and the output shaft OUT and each including three rotating elements, and at least six shifting elements connected to the rotating elements of the first to third planetary gear devices.

The first planetary gear device PG 1 has a first rotating element S 1 which is permanently connected to the input shaft IN and is variably connected to a third rotating element R 3 of the third planetary gear device PG 3 , a second rotating element C 1 which is fixedly installed by any one of the shifting elements and variably connected to the third rotating element R 3 of the third planetary gear device PG 3 , and a third rotating element R 1 which is variably connected to a first rotating element S 2 of the second planetary gear device PG 2 and permanently connected to a first rotating element S 3 of the third planetary gear device PG 3 .

The second planetary gear device PG 2 has a first rotating element S 2 which is fixedly installed by the other one of the shifting elements and variably connected to a first rotating element S 3 of the third planetary gear device PG 3 , a second rotating element C 2 which is permanently connected to the output shaft OUT and variably connected to the first rotating element S 3 of the third planetary gear device PG 3 , and a third rotating element R 2 which is permanently connected to a second rotating element C 3 of the third planetary gear device PG 3 .

The first planetary gear device PG 1 , the second planetary gear device PG 2 , and the third planetary gear device PG 3 are sequentially disposed along a rotating shaft direction of the input shaft IN and the output shaft OUT.

The first planetary gear device PG 1 and the second planetary gear device PG 2 are configured as a single pinion simple planetary gear device and the third planetary gear device PG 3 is configured as a double pinion simple planetary gear device.

The second rotating element C 1 of the first planetary gear device PG 1 is fixedly installed in a transmission case CS by a first brake B 1 among the shifting elements and the first rotating element S 2 of the second planetary gear device PG 2 is fixedly installed to the transmission case CS by a second brake B 2 among the shifting elements.

The rest of the shifting elements are configured to form variable connection structures between the rotating elements of the planetary gear devices.

That is, a first clutch CL 1 among the shifting elements forms a variable connection structure between the first rotating element S 1 of the first planetary gear device PG 1 and the third rotating element R 3 of the third planetary gear device PG 3 , a third clutch CL 3 among the shifting elements forms a variable connection structure between the second rotating element C 1 of the first planetary gear device PG 1 and the third rotating element R 3 of the third planetary gear device PG 3 , a fourth clutch CL 4 among the shifting elements forms a variable connection structure between the first rotating element S 2 of the second planetary gear device PG 2 and the first rotating element S 3 of the third planetary gear device PG 3 , and a second clutch CL 2 among the shifting elements forms a variable connection structure between the second rotating element C 2 of the second planetary gear device PG 2 and the first rotating element S 3 of the third planetary gear device PG 3 .

According to the present exemplary embodiment, the first rotating element S 1 , the second rotating element C 1 , and the third rotating element R 1 of the first planetary gear device PG 1 each are a first sun gear, a first carrier, and a first ring gear, the first rotating element S 2 , the second rotating element C 2 , and the third rotating element R 2 of the second planetary gear device PG 2 each are a second sun gear, a second carrier, and a second ring gear, and the first rotating element S 3 , the second rotating element C 3 , and the third rotating element R 3 of the third planetary gear device PG 3 each are a third sun gear, a third carrier, and a third ring gear.

The multi stage transmission for a vehicle configured as described above may also be represented as follows.

That is, the multi stage transmission for a vehicle according to an exemplary embodiment of the present invention is configured to include the first planetary gear device PG 1 , the second planetary gear device PG 2 , and the third planetary gear device PG 3 each having three rotating elements, the six shifting elements configured to variably provide frictional force, and eight rotating shafts connected to the rotating elements of the planetary gear devices.

Here, a first rotating shaft RS 1 is the input shaft IN directly connected to the first rotating element S 1 of the first planetary gear device PG 1 , a second rotating shaft RS 2 is directly connected to the second rotating element C 1 of the first planetary gear device PG 1 , a third rotating shaft RS 3 is directly connected to the third rotating element R 1 of the first planetary gear device PG 1 and the first rotating element S 3 of the third planetary gear device PG 3 , a fourth rotating shaft RS 4 is directly connected to the third rotating element R 3 of the third planetary gear device PG 3 , a fifth rotating shaft RS 5 is directly connected to the first rotating element S 2 of the second planetary gear device PG 2 , a sixth rotating shaft RS 6 is directly connected to the third rotating element R 2 of the second planetary gear device PG 2 and the second rotating element C 3 of the third planetary gear device PG 3 , and a seventh rotating shaft RS 7 is the output shaft directly connected to the second rotating element C 2 of the second planetary gear device PG 2 .

Further, the first clutch CL 1 among the six shifting elements is installed between the first rotating shaft RS 1 and the fourth rotating shaft RS 4 , the second clutch CL 2 is installed between the third rotating shaft RS 3 and the seventh rotating shaft RS 7 , the third clutch CL 3 is installed between the second rotating shaft RS 2 and the fourth rotating shaft RS 4 , the fourth clutch CL 4 is installed between the third rotating shaft RS 3 and the fifth rotating shaft RS 5 , the first brake B 1 is installed between the second rotating shaft RS 2 and the transmission case CS, and the second brake B 2 is installed between the fifth rotating shaft RS 5 and the transmission case CS.

Since the multi stage transmission for a vehicle according to an exemplary embodiment of the present invention including the three simple planetary gear devices and the six shifting elements as described above may implement forward nine stages and reverse one stage depending on an operation mode table as shown in FIG. 2 , it may implement a multi stage shifting stage of nine stages by a relatively small number of components and a simple configuration to contribute to improvement of fuel efficiency and silence of the vehicle, thereby making it possible to improve salability of the vehicle.

As set forth above, according to exemplary embodiment of the present invention, at least forward nine stages and reverse one stage or more are implemented by a comparatively small number of components and a simple configuration, thereby making it possible to maximize fuel efficiency improvement of the vehicle through driving at an optimal driving point of an engine and improve silence of the vehicle through more silent driving of the engine.

For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.