WO2014126282A1

WO2014126282A1 - Continuously variable automatic transmission

Info

Publication number: WO2014126282A1
Application number: PCT/KR2013/001254
Authority: WO
Inventors: 김태훈
Original assignee: 현대파워텍 주식회사
Priority date: 2013-02-18
Filing date: 2013-02-18
Publication date: 2014-08-21

Abstract

The invention relates to a continuously variable automatic transmission, comprising: a first input shaft to which the power of an engine is transferred; a second input shaft to which the power of the engine is transferred from the first input shaft; a belt drive unit which is installed between the first input shaft and the second input shaft and shifts gears; a first planetary gear set connected to the second input shaft; a second planetary gear set which is connected to the second input shaft, connected to the outer circumferential surface of the first planetary gear set, and also connected to an output shaft; and friction elements which are installed in the first planetary gear set and the second planetary gear set and implements two forward shift stages and one reverse shift stage.

Description

Continuously Variable Automatic Transmission

The present invention relates to a continuously variable automatic transmission, and more particularly, to a continuous variable automatic transmission that can reduce the overall length of the transmission.

The conventional Continuously Variable Transmission (CVT) is a transmission that can control the gear ratio to a near infinite stage within a given range.

In contrast to other transmissions that can control the gear ratio in only a few predetermined steps, it is also called a continuously variable transmission.

The continuously variable transmission drives the engine at the most efficient rotational speed (RPM) according to the speed of the vehicle.

Belt Drive Method The drive system of the continuously variable transmission transmits power by hanging a belt between two pulleys.

The pulley which is installed on the input shaft which is directly connected to the engine and rotates is called the main pulley, and the pulley which is installed on the output shaft and is connected to the main pulley by the belt is called the pulley.

Between the main pulley and the output shaft, a general planetary gear set or a planet type planetary gear set is installed to implement a plurality of shift stages.

Background art of the present invention is disclosed in Republic of Korea Patent Publication No. 10-2011-0033260 (published on March 30, 2011, the name of the invention: pulley support structure and belt type continuously variable transmission of the belt type continuously variable transmission).

The conventional continuous variable automatic transmission has a problem in that it is difficult to reduce the overall length of the transmission because a general planetary gear set or a planetary gear set of a rib type is installed between the main pulley and the output shaft.

Therefore, there is a need for improvement.

It is an object of the present invention to provide a continuously variable automatic transmission that can reduce the overall length of the transmission.

Continuously variable automatic transmission according to the present invention comprises: a first input shaft to which the power of the engine is transmitted; A second input shaft through which power of the engine is transmitted from the first input shaft; A belt driving unit installed between the first input shaft and the second input shaft to perform a shift operation; A first planetary gear set connected to the second input shaft; A second planetary gear set connected to the second input shaft, connected to an outer circumferential surface of the first planetary gear set, and connected to an output shaft; And a friction element installed in the first planetary gear set and the second planetary gear set, and configured to implement a shift stage of forward two speeds and reverse one speeds.

Preferably, the first planetary gear set and the second planetary gear set are connected by a carrier consisting of one plate.

More preferably, the first planetary gear set includes: a first sun gear that is restrained or released by the friction element; A first planetary gear geared to the first sun gear and constrained or released by the friction element; And a first ring gear connected to the first planetary gear and connected to the second input shaft.

More preferably, the second planetary gear set includes: a second planetary gear geared to the first ring gear and connected to the first planetary gear; And a second ring gear connected to the second planetary gear and connected to the output shaft.

More preferably, a ring gear portion geared to the first planetary gear is formed on an inner wall of the first ring gear, and a sun gear portion geared to the second planetary gear is formed on an outer wall of the first ring gear.

More preferably, the first ring gear serves as a ring gear of the first planetary gear set by the ring gear part and serves as a sun gear of the second planetary gear set by the sun gear part.

More preferably, the first planetary gear and the second planetary gear are rotatably connected to the carrier made of one plate.

More preferably, the second planetary gear set is geared to an outer circumferential surface of the first planetary gear set.

More preferably, the friction element may include a first brake installed between the first sun gear and the case; A second brake disposed between the carrier and the case; And a clutch installed between the first ring gear and the second ring gear.

According to the present invention, since the second planetary gear set is geared to the outer circumferential surface of the first planetary gear set, the first planetary gear set and the second planetary gear set are positioned on the same plane without being spaced apart from each other. As a result, the overall length can be shortened compared to the conventional automatic transmission in which the first planetary gear set and the second planetary gear set are not arranged on the same plane, thereby reducing the space required for transmission installation.

Further, according to the present invention, since the ring gear of the first planetary gear set and the sun gear of the second planetary gear set are formed integrally with the first ring gear, the second planetary gear set may be geared to the outer circumferential surface of the first planetary gear set. This reduces the overall length of the transmission.

According to the present invention, the first ring gear can simultaneously serve as a ring gear of the first planetary gear set and a sun gear of the second planetary gear set.

In addition, according to the present invention, since the first planetary gear and the second planetary gear are rotatably connected to the carrier made of one plate, the number of carriers can be reduced, and the overall length of the transmission can be reduced by the thickness of the carrier, which is omitted. can.

1 is a block diagram showing a continuous variable automatic transmission according to an embodiment of the present invention.

2 is a cross-sectional view illustrating a connection structure between a first planetary gear set and a second planetary gear set of a continuously variable automatic transmission according to an embodiment of the present invention.

3 is a graph showing a lever analysis of a continuously variable automatic transmission according to an embodiment of the present invention.

4 is an operation table of a continuously variable automatic transmission according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of a continuous variable automatic transmission according to the present invention. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or custom. Therefore, the definitions of these terms should be made based on the contents throughout the specification.

1 is a block diagram showing a continuous variable automatic transmission according to an embodiment of the present invention, Figure 2 is a first planetary gear set and a second planetary gear of the continuous variable automatic transmission according to an embodiment of the present invention Figure 3 is a cross-sectional view showing a connection structure of the set, Figure 3 is a graph showing a lever analysis of a continuously variable automatic transmission according to an embodiment of the present invention, Figure 4 is a continuously variable automatic according to an embodiment of the present invention The operation table of the transmission.

1 to 4, a continuous variable automatic transmission according to an exemplary embodiment of the present invention includes a first input shaft 12 through which power of an engine is transmitted, and power of the engine from a first input shaft 12. The first planetary gear set is connected between the second input shaft 14, the first input shaft 12 and the second input shaft 14 to perform the shifting operation, and the first planetary gear set connected to the second input shaft 14. A second planetary gear set 70 connected to the second input shaft 14 and connected to an outer circumferential surface of the first planetary gear set 50, and connected to the output shaft 92, and a first planetary gear set ( 50) and friction elements (82, 84, 86) installed in the second planetary gear set (70) and which implements a shift stage of forward 2 speed reverse 1 speed.

When the engine is driven, power of the engine transmitted through the first input shaft 12 is supplied to the first planetary gear set 50 by the second input shaft 14 through the belt driving unit 30.

At this time, since the outer diameters of the driving pulley 32 and the driven pulley 34 vary according to the speed change of the vehicle, the power of the engine transmitted from the first input shaft 12 is driven by the driving pulley 32, Passed through the belt 36 and the driven pulley 34 is transmitted to the second input shaft (14).

The power of the engine transmitted through the second input shaft 14 passes through the first planetary gear set 50 and the second planetary gear set 70 and is transmitted to the drive shaft 96 through the output shaft 92. By the operation of (82, 84, 86), it is possible to realize the shift stage of the forward 2 speed reverse 1 speed.

A main gear 94 is installed in the output shaft 92, and a driven gear 98 geared with the main gear 94 is installed in the drive shaft 96 to which the differential device is connected.

The first planetary gear set 50 includes a first sun gear 52 and a first sun gear 52 that are restrained or released by the first brake 82 to be described later among the

friction elements

82, 84, and 86. The first planetary gear 54 connected to the first planetary gear 54 and restrained or released by the second brake 84 to be described later among the

friction elements

82, 84, and 86. And a first ring gear 58 connected to 14).

The second planetary gear set 70 has a second planetary gear 74 geared to the first ring gear 58 and connected to the first planetary gear 54 and a gear connection to the second planetary gear 74. And a second ring gear 76 connected to the output shaft 92.

Power of the engine transmitted through the second input shaft 14 is input through the first ring gear 58 and transmitted to the output shaft 92 through the second planetary gear 74 and the second ring gear 76. It is then transmitted to the drive shaft 96 through the main gear 94 and the driven gear (98).

At this time, the first sun gear 52, the first planetary gear 54, and the second planetary gear 74 are operated by the first brake 82 and the second brake 84 among the

friction elements

82, 84, and 86. ) Is constrained or released, enabling a two-speed forward gear.

The first ring gear 58 is formed in a ring shape, and a ring gear portion 56 geared to the first planetary gear 54 is formed on an inner wall of the first ring gear 58, and the first ring gear 58 is formed. On the outer wall of the) is formed a sun gear portion 72 in gear connection with the second planetary gear (74).

Since the ring gear portion 56 is formed on the inner circumferential surface of the first ring gear 58 and the sun gear portion 72 is formed on the outer circumferential surface of the first ring gear 58, the first ring gear 58 is formed of the first planetary gear set. It serves as a ring gear and a sun gear of the second planetary gear set 70 at the same time.

As described above, since the ring gear of the first planetary gear set 50 and the sun gear of the second planetary gear set 70 are integrally formed, the second planetary gear set 70 is formed on the outer circumferential surface of the first planetary gear set 50. Is geared to reduce the overall length of the transmission.

In addition, since the first planetary gear 54 and the second planetary gear 74 are rotatably connected to the carrier 74a formed of one plate, the number of carriers 74a can be reduced, and the thickness of the carrier omitted. This reduces the overall length of the transmission.

The

friction elements

82, 84, and 86 include a first brake 82 provided between the first sun gear 52 and the case 10, a carrier 74a and a case 10 of the first planetary gear 54. The second brake 84 is installed between the) and the clutch 86 is provided between the sun gear portion 72 and the second ring gear 76.

When the first brake 82 is actuated, the first sun gear 52 is restrained so that when the engine power is transmitted to the first ring gear 58, the first planetary gear 54 forms an outer circumferential surface of the first sun gear 52. Therefore, the gear shifting operation is performed while idling.

When the second brake 84 is operated, the carrier 74a connected to the first planetary gear 54 and the second planetary gear 74 is restrained.

Therefore, the first planetary gear 54 and the second planetary gear 74 are rotated by the engine power transmitted through the ring gear 56 and the sun gear 72 to transmit reverse rotational power, thereby shifting the speed of the reverse first speed. Will be implemented.

When the clutch 86 is operated, the sun gear portion 72 and the second ring gear 76 are connected by the clutch 86, so that the power of the engine transmitted through the second input shaft 14 passes through the clutch 86 to the output shaft. It is transmitted to (92) to implement the shift speed of the second forward.

Looking at the operation of the continuous variable automatic transmission according to an embodiment of the present invention configured as described above are as follows.

When driving of the vehicle is started, the first brake 82 is operated to transmit power of the engine transmitted through the first input shaft 12 to the first pulley 32, the belt 36, and the driven pulley 34. It is transmitted to the ring gear 58.

The power of the engine transmitted to the sun gear portion 72 of the first ring gear 58 passes through the second planetary gear 74 and the second ring gear 76, and the main gear 94, the driven gear 98, and the drive shaft. It is transmitted to the driving wheel along (96) to implement the gear shift speed of the forward 1 speed.

At this time, since the first sun gear 52 is constrained by the operation of the first brake 82, the first planetary gear 54 revolves along the outer circumferential surface of the first sun gear 52, and the first planetary gear 54 is coupled with the first planetary gear 54. The second planetary gear 74 connected by the carrier 74a revolves along the outer circumferential surface of the sun gear portion 72 to perform the deceleration operation.

When the vehicle speed is increased and the shift speed of the second forward speed is required, the operation of the first brake 82 is released and the clutch 86 is operated so that the second input shaft 14 and the output shaft 92 are connected.

Therefore, the power of the engine transmitted through the second input shaft 14 passes through the clutch 86 and is transmitted to the drive shaft 96 through the output shaft 92, thereby implementing a speed shift stage of the second forward speed.

When the shift stage of the reverse first speed is operated by the driver's operation, the carrier 74a is restrained because the first brake 82 and the clutch 86 are released and the second brake 84 is operated.

Therefore, the power of the engine input through the ring gear portion 56 and the sun gear portion 72 is transmitted to the output shaft 92 along the second planetary gear 74 and the second ring gear 76, and the carrier 74a is Since the second planetary gear 74 rotates, the reverse rotational power is transmitted to implement the shift stage of the reverse 1 speed.

Here, the first planetary gear set 50 and the second planetary gear set 70 are formed of a single planetary gear set, and the second planetary gear set 70 is arranged side by side in the outer diameter direction of the first planetary gear set 50. As a result, the front and rear lengths of the transmission, that is, the overall length of the transmission, are shortened.

As a result, it is possible to provide a continuous variable automatic transmission that can reduce the total length of the transmission.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand.

In addition, the vehicle has been described as an example of a continuous variable automatic transmission, but this is merely exemplary, the continuous variable automatic transmission of the present invention can be used in other products other than the vehicle.

Therefore, the true technical protection scope of the present invention will be defined by the claims below.

Claims

A first input shaft through which power of the engine is transmitted;

A second input shaft through which power of the engine is transmitted from the first input shaft;

A belt driving unit installed between the first input shaft and the second input shaft to perform a shift operation;

A first planetary gear set connected to the second input shaft;

A second planetary gear set connected to the second input shaft, connected to an outer circumferential surface of the first planetary gear set, and connected to an output shaft; And

And a friction element installed in the first planetary gear set and the second planetary gear set, the friction element embodying a shift stage of forward two speed and reverse one speed.
The method of claim 1,

And the first planetary gear set and the second planetary gear set are connected by a carrier made of one plate.
The method of claim 2, wherein the first planetary gear set,

A first sun gear constrained or released by the friction element;

A first planetary gear geared to the first sun gear and constrained or released by the friction element; And

And a first ring gear connected to the first planetary gear and connected to the second input shaft.
The method of claim 3, wherein the second planetary gear set,

A second planetary gear connected to the first ring gear and connected to the first planetary gear; And

And a second ring gear connected to the second planetary gear and connected to the output shaft.
The method of claim 4, wherein

A ring gear part geared to the first planetary gear is formed on an inner wall of the first ring gear, and a sun gear part geared to the second planetary gear is formed on an outer wall of the first ring gear. Automatic transmission.
The method of claim 5, wherein the first ring gear,

And a ring gear of the first planetary gear set by the ring gear unit, and a sun gear of the second planetary gear set by the sun gear unit.
The method of claim 6,

And the first planetary gear and the second planetary gear are rotatably connected to the carrier made of one plate.
The method of claim 7, wherein

And the second planetary gear set is geared to an outer circumferential surface of the first planetary gear set.
The method of claim 7, wherein the friction element,

A first brake installed between the first sun gear and the case;

A second brake disposed between the carrier and the case; And

And a clutch provided between the first ring gear and the second ring gear.