KR20200114476A - Transmission for electric vehicle - Google Patents

Abstract

The present invention relates to a transmission for an electric vehicle, including: an input shaft connected to a first motor capable of forward and reverse rotation; a drive gear installed on the input shaft, and a power transmission gear disposed in engagement with the drive gear; a first output gear that is connected to the power transmission gear, transmits the driving force of the power transmission gear in a basic mode and a reverse mode, and comprises a planetary gear set that changes the torque and rotational speed from the transmitted driving force to transmit it to the outside by receiving separate driving force of a second motor in a shift mode; and an output shaft to which a second output gear disposed in engagement with the first output gear is shaft-coupled to transmit rotational torque to a wheel.

Description

Transmission for electric vehicles{TRANSMISSION FOR ELECTRIC VEHICLE}

The present invention relates to a transmission for an electric vehicle, and more particularly, the power transmitted by the first motor and the second motor is transmitted to the sun gear and the carrier of the planetary gear set, respectively, and converts it into output power to enable continuous transmission. It relates to a transmission for an electric vehicle.

In general, internal combustion engines such as gasoline engines and diesel engines used as prime movers for automobiles burn fossil fuels in cylinders and use heat energy generated at this time as power. Therefore, the exhaust gas contains harmful components such as nitrogen oxides (Nox) due to combustion and carbon monoxide (CO) or hydrocarbons (HC) due to incomplete combustion. These components pollute the atmosphere with the increase of vehicles and are harmful to the human body, causing pollution problems.

Accordingly, various exhaust gas measures have been taken to reduce harmful components in automobiles using internal combustion engines, but the harmful components contained in the exhaust gas cannot be completely removed. Therefore, as part of the exhaust gas countermeasure, attention is paid to electric vehicles that have low noise and do not emit any exhaust gas.

Electric vehicles operate using a motor that receives electricity from a battery rather than an engine that generates power using fossil fuels such as gasoline or diesel. Accordingly, the energy efficiency of a motor of an electric vehicle that does not emit carbon dioxide is higher than that of an internal combustion engine vehicle engine, and thus, is in the spotlight as an eco-friendly vehicle.

In addition, electric vehicles are provided with a reduction gear in place of a transmission of a general internal combustion engine vehicle.

Unlike the engine, the rotational speed of the motor is easily controlled, so that the rotational speed of the motor is controlled according to the driving speed, and the reducer is responsible for decelerating and outputting the rotation of the motor rotational shaft at a constant rate.

However, the electric motor has a characteristic that the torque varies depending on the rotational speed (rpm). Electric motors have the characteristic of generating the largest torque during initial start-up. If the amount of current is increased to compensate for the falling torque after acceleration, the leakage heat energy increases, so motor efficiency decreases.

Accordingly, in recent years, attempts have been made to install a transmission in an electric vehicle to control the rotation of the motor within a driving range with the best motor efficiency, and to provide a torque suitable for the driving situation of the vehicle through the transmission.

As the application range of electric vehicles increases, it is essential to provide high torque, especially for safe operation of small trucks.

Korean Registered Patent Publication No.1335393 (2013.11.26)

Accordingly, the present invention was conceived to solve the above problems, and an object of the present invention is to convert the rotational power of the sun gear and the carrier of the planetary gear set into output power through the ring gear, so that a continuous transmission is possible or It is to provide a transmission for an electric vehicle capable of continuously variable transmission.

In order to achieve the above object, the present invention includes an input shaft connected to a first motor capable of forward and reverse rotation; A drive gear installed on the input shaft, a power transmission gear disposed in engagement with the drive gear; It is connected to the power transmission gear, and the driving force of the power transmission gear is transmitted in the basic mode and the reverse mode, and the driving force of a separate second motor is transmitted in the shift mode, and the torque and rotation speed are changed from the transmitted driving force and transmitted to the outside. A first output gear made of a planetary gear set; And an output shaft for transmitting a rotational torque to a wheel by coupling a second output gear disposed in engagement with the first output gear.

According to an embodiment of the present invention, the first output gear may include a sun gear disposed at the center; A plurality of planetary gears disposed on the outer circumferential surface of the sun gear so as to mesh with the sun gear; A ring gear disposed outside the planetary gears so as to mesh with the planetary gears; And, a carrier connecting each central axis of the planetary gears; consisting of a planetary gear set including.

According to an embodiment of the present invention, in the basic mode and the reverse mode, the power transmission gear is axially coupled to the sun gear of the first output gear.

According to an embodiment of the present invention, it further includes a second motor connected to the carrier of the first output gear to transmit power in the shift mode.

According to an embodiment of the present invention, in the basic mode and the reverse mode, the power transmission gear is connected to a carrier of the first output gear.

According to an embodiment of the present invention, it further includes a second motor that is axially coupled to the sun gear of the first output gear to transmit power in the shift mode.

According to the transmission for an electric vehicle according to the present invention having the configuration as described above, by converting the rotation power of the sun gear and the carrier of the planetary gear set into output power through the ring gear, the load received by each gear in the planetary gear set is small, Since shifting is possible without synchronization, it is possible to alleviate a shift shock that occurs during gear shifting, thereby improving the performance of an electric vehicle.

1 is a view showing an overall configuration of a transmission for an electric vehicle according to a first embodiment of the present invention.
2 is a diagram showing a basic mode state of an electric vehicle according to the first embodiment of the present invention.
3 is a view showing a basic mode state of a planetary gear set of an electric vehicle according to the first embodiment of the present invention.
4 is a view showing a state of a shift mode of an electric vehicle according to the first embodiment of the present invention.
5 is a view showing a state of a shift mode of a planetary gear set of an electric vehicle according to the first embodiment of the present invention.
6 is a diagram illustrating a state in a reverse mode of an electric vehicle according to the first embodiment of the present invention.
7 is a diagram illustrating a state in a reverse mode of a planetary gear set of an electric vehicle according to the first embodiment of the present invention.
8 is a view showing an overall configuration of a transmission for an electric vehicle according to a second embodiment of the present invention.
9 is a diagram illustrating a basic mode state of an electric vehicle according to a second embodiment of the present invention.
10 is a view showing a basic mode state of a planetary gear set of an electric vehicle according to a second embodiment of the present invention.
11 is a diagram showing a state of a shift mode of an electric vehicle according to a second embodiment of the present invention.
12 is a view showing a state of a shift mode of a planetary gear set of an electric vehicle according to a second embodiment of the present invention.
13 is a diagram illustrating a state in a reverse mode of an electric vehicle according to a second embodiment of the present invention.
14 is a view showing a state in a reverse mode of a planetary gear set of an electric vehicle according to a second embodiment of the present invention.

The present invention will be described in detail in the text, since various modifications can be made and various forms can be obtained. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals have been used for similar elements.

These terms are used only for the purpose of distinguishing one component from another component. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an overall configuration of a transmission for an electric vehicle according to a first embodiment of the present invention, FIG. 2 is a view showing a basic mode state of an electric vehicle according to the first embodiment of the present invention, and FIG. 3 is A diagram showing a basic mode state of a planetary gear set of an electric vehicle according to a first embodiment of the present invention, FIG. 4 is a diagram showing a state of a shift mode of an electric vehicle according to the first embodiment of the present invention, and FIG. 5 FIG. 6 is a view showing a state of a shift mode of a planetary gear set of an electric vehicle according to a first embodiment of the present invention, FIG. 6 is a view showing a state of a reverse mode of an electric vehicle according to the first embodiment of the present invention, and FIG. 7 A diagram showing a state in a reverse mode of a planetary gear set of an electric vehicle according to the first embodiment of the present invention.

As shown in FIG. 1, the transmission for an electric vehicle according to an embodiment of the present invention is connected to an electrically driven first motor M1 and capable of forward and reverse rotation by a rotational operation of the first motor M1. It includes an input shaft (100).

The function according to the main configuration of the transmission of the electric vehicle according to the present invention is to change the number of revolutions and torque from the power transmitted from the input shaft 100 between the input shaft 100 and the output shaft 300 to vary the speed according to the driving state of the vehicle. It is controlled so that it can be operated with

Here, the first motor M1 is a type of motor that is driven by receiving power from a battery module not shown installed in the electric vehicle, and in the present invention, the electric vehicle obtained from the battery module that supplies all the power for driving the vehicle The description is limited to the case.

In addition, the first motor M1 is capable of forward and reverse rotation so that one side rotation (counterclockwise rotation) is used as a basic mode and a shift mode, and the other side rotation (clockwise rotation) is used as a reverse mode. .

Here, the basic mode represents a one-stage shift mode, and the shift mode represents a continuously shifting or stepless, multi-speed mode.

In addition, the present invention is disposed in parallel with the input shaft 100, the output shaft 300 that generates a rotation torque to rotate the wheel through a rotating operation, and the first is installed between the input shaft 100 and the output shaft 300. It includes a power transmission shaft 200 for transmitting the driving force of the motor (M1) to the output shaft (300).

The driving gear 110 is disposed on the input shaft 100 and the power transmission shaft 200 disposed parallel to the input shaft 100 is engaged with the driving gear 110 to reduce the rotational force of the driving gear 110 to the first output gear 220. ), the power transmission gear 210 is disposed.

As shown, the drive gear 110 axially coupled to the input shaft 100 is formed to mesh with the power transmission gear 210 axially coupled to the power transmission shaft 200.

The first output gear 220 meshed with the second output gear 230 of the output shaft 300 is composed of a planetary gear set and transmits rotational force through it, so that the transmission ratio of the basic mode, the shift mode and the reverse mode can be realized. .

The planetary gear set includes a sun gear 221 disposed at the center, a plurality of planetary gears 222 disposed outside the sun gear 221 so as to be engaged and coupled with the sun gear 221, and a planetary gear to be engaged with the planetary gear 222. It includes a ring gear 223 disposed on the outside of the 222, and a carrier 224 connecting each central axis of the plurality of planetary gears 222.

A gear tooth is formed on the inner circumferential surface of the ring gear 223, and a sun gear 221 with a gear tooth formed on the outer circumferential surface is disposed at the center of the ring gear 223, and a ring gear 221 between the ring gear 223 and the sun gear 221 223) and a plurality of planetary gears 222 having gear teeth formed on the outer circumferential surface so as to mesh with the gear teeth of the sun gear 221 are spaced apart from each other, and a carrier 224 on the central axis of each planetary gear 222 Is connected integrally.

The power transmission shaft 200 is axially coupled to the sun gear 221 of the planetary gear set, so that the driving force of the first motor M1 is transmitted through the driving gear 110 and the power transmission gear 210.

Here, the first motor M1 may be directly connected to the sun gear 221 of the planetary gear set so that the driving force of the first motor M1 may be directly transmitted to the sun gear 221.

However, by controlling the rotation torque of the output shaft 300 by adjusting the gear ratio of the driving gear 110 and the power transmission gear 210, the energy loss in the power transmission process of the first motor M1 can be reduced. It can be configured as an indirect delivery method.

The carrier 224 connects the central axes of the plurality of planetary gears 222, and in an embodiment of the present invention may be formed in a polygonal shape proportional to the number of planetary gears 222.

In such a planetary gear set, which is the first output gear 220, the rotation is quiet because a plurality of gears are always engaged, and the transmission of the rotational force is performed by several gear trains, so that the load received by each gear is small, and it can be shifted without synchronization. Therefore, it is possible to change the speed without blocking the power of the first motor M1 transmitted by the input shaft 100, and it is possible to alleviate a shift shock generated during gear shifting.

The carrier 224 of the planetary gear set is connected to a separate second motor M2, and can be continuously shifted or rotated in one direction by the second motor M2 in a shift mode such as continuously shifting. In the basic mode and the reverse mode, since the second motor M2 is not driven, the second motor M2 is in a stopped state, and the planetary gear 222 is rotated by the rotation of the sun gear 221.

This planetary gear set basically consists of the above configuration and operation, but is not necessarily limited thereto, and various planetary gear sets may be adopted.

The first motor (M1) and the second motor (M2) drive the first motor (M1) and the second motor (M2) as a generator using the kinetic energy of the car instead of braking by conventional friction when braking the car. And, after the electric energy generated at this time is stored in a battery, regenerative braking that is reused when the vehicle is driven may be performed.

A power transmission process of the transmission for an electric vehicle according to the first embodiment of the present invention configured as described above will be described as follows.

First, as shown in FIGS. 2 and 3, a basic mode of an electric vehicle will be described.

When the basic mode signal is applied to the transmission due to the operation of the electric vehicle, the first motor M1 rotates counterclockwise.

The rotational force of the first motor M1 is transmitted to the input shaft 100 and is transmitted to the power transmission shaft 200 in a clockwise direction through the power transmission gear 210 meshing with the driving gear 110.

The rotational force transmitted to the power transmission shaft 200 is transmitted to the sun gear 221 of the planetary gear set, which is the first output gear 220, and the sun gear 221 applies rotational force to the planetary gear 222 and the ring gear 223. Deliver.

The rotational force in the counterclockwise direction transmitted to the ring gear 223 is transmitted to the wheels through the output shaft 300 so that the electric vehicle moves forward in a basic mode state.

The carrier 224 is connected to the central axis of the plurality of planetary gears 222 and at the same time is connected to the second motor M2 to maintain a stopped state. Therefore, the planetary gear 222 rotates in a counterclockwise direction in place along the inner circumferential surface of the ring gear 223 around the sun gear 221, and the rotation speed of the sun gear 221 is transmitted to the ring gear 223 as it is. Therefore, the second output gear 230 meshed with the ring gear 223 rotates at the same speed as the rotation speed of the sun gear 221 to transmit power to the output shaft 300.

As the rotation speed output to the output shaft 300 becomes slower than the rotation speed of the first motor M1, the rotation speed transmitted to the wheel is a rotation speed that is slower than the input shaft 100 and a high torque is generated.

As described above, the carrier 224 connected to the planetary gear 222 of the planetary gear set maintains a stopped state due to the second motor M2 being not driven.

As shown in FIGS. 4 and 5, the shift mode of the electric vehicle will be described as follows.

In the basic mode state in which the rotational force of the first motor M1 is transmitted to the wheels through the output shaft 300, in the shift mode, the second motor M2 is counterclockwise in the same rotation direction as the first motor M1. Will rotate.

The rotational force in the counterclockwise direction of the second motor M2 is transmitted to the carrier 224, and the rotational force of the carrier 224 is transmitted as a rotational force in the counterclockwise direction to the ring gear 223 through the revolution of the planetary gear 222. do.

Therefore, in the shift mode, the driving force of the first motor M1 is transmitted to the ring gear 223 through the sun gear 221 and the planetary gear 222 in the basic mode, so that the ring gear 223 rotates counterclockwise. In this state, the driving force of the second motor M2 is additionally transmitted to the ring gear 223 through the carrier 224 and the planetary gear 222, thereby increasing the rotational power of the ring gear 223.

In this way, since the power input from the first motor M1 and the second motor M2 is output through the sun gear 221 and the carrier 224 of the first output gear 220, respectively, the ring gear in the shift mode ( As the speed of 223 is continuously rotated at an increased speed than that of the ring gear 223 in the basic mode, a low torque is generated.

The rotational force in the counterclockwise direction transmitted to the ring gear 223 is transmitted to the wheels through the output shaft 300 so that the electric vehicle moves forward in the shift mode state.

As shown in FIGS. 6 and 7, the reverse mode of the electric vehicle will be described as follows.

The reverse mode has the same power transmission structure as the basic mode, but the rotation direction of the first motor M1 is opposite.

When the reverse mode signal is applied to the transmission due to the operation of the electric vehicle, the first motor M1 rotates clockwise.

The rotational force in the clockwise direction of the first motor M1 is transmitted to the input shaft 100 and is transmitted to the power transmission shaft 200 in a counterclockwise direction through the power transmission gear 210 meshing with the driving gear 110.

The rotational force in the counterclockwise direction transmitted to the power transmission shaft 200 is transmitted to the sun gear 221 of the planetary gear set, which is the first output gear 220, and the sun gear 221 transmits the rotational force to the planetary gear 222. .

The rotational force in the clockwise direction transmitted to the planetary gear 222 is transmitted to the output shaft 300 through the ring gear 223, and transmitted to the wheels through the output shaft 300 so that the electric vehicle moves backward in a reverse mode state.

Hereinafter, in describing the second embodiment of the transmission for an electric vehicle according to the present invention, the same names and constituent symbols are used for configurations having the same configuration and functions as in the first embodiment of the present invention, and to avoid repetitive configurations. Detailed descriptions of these configurations will be omitted.

8 is a diagram showing the overall configuration of a transmission for an electric vehicle according to a second embodiment of the present invention, FIG. 9 is a view showing a basic mode state of an electric vehicle according to the second embodiment of the present invention, and FIG. A diagram showing a basic mode state of a planetary gear set of an electric vehicle according to a second embodiment of the present invention, FIG. 11 is a view showing a state of a shift mode of an electric vehicle according to a second embodiment of the present invention, and FIG. FIG. 13 is a view showing a state in a shift mode of a planetary gear set of an electric vehicle according to a second embodiment of the present invention, FIG. 13 is a view showing a state in a reverse mode of an electric vehicle according to a second embodiment of the present invention, and FIG. A diagram showing a state in a reverse mode of a planetary gear set of an electric vehicle according to a second embodiment of the present invention.

As shown in FIG. 8, a drive gear 110 is disposed on the input shaft 100 and a power transmission gear 210 is connected to the drive gear 110 to be connected to the carrier 224 of the planetary gear set.

Here, the first motor M1 is directly connected to the planetary gear set, which is the first output gear 220, so that the driving force of the first motor M1 can be directly transmitted to the planetary gear set.

However, by controlling the rotation torque of the output shaft 300 by adjusting the gear ratio of the driving gear 110 and the power transmission gear 210, the energy loss in the power transmission process of the first motor M1 can be reduced. It can be configured as an indirect delivery method.

In addition, the second motor M2 is connected to the sun gear 221 of the planetary gear set by the power transmission shaft 200, and one-way rotation is possible by the second motor M2 in the shift mode state.

In the basic mode and the reverse mode, since the second motor M2 is in a non-driving state, the sun gear 221 is in a stopped state, and the planetary gear 222 revolves along the rotation direction of the carrier 224 and the sun gear 221 And rotates along the ring gear 223.

A power transmission process of the transmission for an electric vehicle according to the first embodiment of the present invention configured as described above will be described as follows.

First, as shown in FIGS. 9 and 10, a basic mode of an electric vehicle will be described.

When the basic mode signal is applied to the transmission due to the operation of the electric vehicle, the first motor M1 rotates clockwise.

The rotational force in the clockwise direction of the first motor M1 is transmitted to the input shaft 100 and transmitted in a counterclockwise direction to the planetary gear set carrier 224 through the power transmission gear 210 meshing with the driving gear 110. .

The rotational force transmitted to the carrier 224 of the planetary gear set, which is the first output gear 220, is transmitted to the ring gear 223.

The rotational force in the counterclockwise direction transmitted to the ring gear 223 is sequentially transmitted to the wheels through the second output gear 230 and the output shaft 300 so that the electric vehicle moves forward in a basic mode state.

In the sun gear 221, a plurality of planetary gears 222 are arranged along the outer circumferential surface so that the planetary gear 222 revolves in a counterclockwise direction with the carrier 224 between the sun gear 221 and the ring gear 223. , Since the rotational speed of the carrier 224 is transmitted to the ring gear 223 as it is, the second output gear 230 meshed with the ring gear 223 rotates at the same speed as the rotational speed of the carrier 224, so that the output shaft ( 300).

As the rotation speed output to the output shaft 300 becomes slower than the rotation speed of the first motor M1, the rotation speed transmitted to the wheel is a rotation speed that is slower than the input shaft 100 and a high torque is generated.

At this time, the sun gear 221 of the planetary gear set maintains a stopped state due to the non-driving state of the second motor M2.

As shown in FIGS. 11 and 12, the shift mode of the electric vehicle will be described as follows.

In the basic mode state in which the rotational force of the first motor M1 is transmitted to the wheels through the output shaft 300, in the shift mode, the second motor M2 is clockwise in the same rotation direction as the first motor M1. It will rotate.

The rotational force of the second motor M2 is transmitted to the sun gear 221, and the rotational force of the sun gear 221 is transmitted to the ring gear 223 as a counterclockwise rotational force through the planetary gear 222.

Therefore, in the shift mode, the driving force of the first motor M1 is transmitted to the ring gear 223 through the carrier 224 and the planetary gear 222 in the basic mode, so that the ring gear 223 rotates counterclockwise. In this state, the driving force of the second motor M2 is additionally transmitted to the ring gear 223 through the sun gear 221 and the planetary gear 222, thereby increasing the rotation power of the ring gear 223.

In this way, the power input from the first motor M1 and the second motor M2 is output through the carrier 224 and the sun gear 221 of the first output gear 220, respectively, so that the ring gear in the shift mode ( As the speed of 223 is continuously rotated at an increased speed than that of the ring gear 223 in the basic mode, a low torque is generated.

The rotational force in the counterclockwise direction transmitted to the ring gear 223 is transmitted to the wheels through the output shaft 300 so that the electric vehicle moves forward in the shift mode state.

13 and 14, the reverse mode of the electric vehicle will be described as follows.

The reverse mode has the same power transmission structure as the basic mode, but the rotation direction of the first motor M1 is opposite.

When the reverse mode signal is applied to the transmission due to the operation of the electric vehicle, the first motor M1 rotates counterclockwise.

The rotational force in the counterclockwise direction of the first motor M1 is transmitted to the input shaft 100 and is transmitted in a clockwise direction to the carrier 224 of the planetary gear set through the power transmission gear 210 meshing with the driving gear 110. .

The rotational force transmitted to the carrier 224 of the planetary gear set, which is the first output gear 220, transmits the rotational force in the clockwise direction to the planetary gear 222.

The rotational force in the clockwise direction transmitted to the planetary gear 222 is transmitted to the output shaft 300 through the ring gear 223, and transmitted to the wheels through the output shaft 300 so that the electric vehicle moves backward in a reverse mode state.

Accordingly, in the present invention, the basic mode and the reverse mode are implemented by forward and reverse rotation of the first motor M1, and the shift mode is driven in a direction in which the second motor M2 increases the speed of the carrier 224, The rotation power of the sun gear 221 and the carrier 224 of the gear set are collected and converted into output power through the ring gear 223.

In particular, while the load received by each gear in the planetary gear set is small, shifting is possible even without synchronization, so it is possible to improve the performance of an electric vehicle by reducing a shift shock generated during gear shifting.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains can understand that it is possible to easily transform it into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of the present invention is indicated by the claims to be described later, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

100: input shaft 110: drive gear
200: power transmission shaft 210: power transmission gear
220: first output gear 221: sun gear
222: planetary gear 223: ring gear
224: carrier 230: second output gear
300: output shaft M1: first motor
M2: 2nd motor

Claims (6)

An input shaft connected to a first motor capable of forward and reverse rotation;
A drive gear installed on the input shaft, a power transmission gear disposed in engagement with the drive gear;
It is connected to the power transmission gear, and in the basic mode and the reverse mode, the driving force of the power transmission gear is transmitted. A first output gear made of a planetary gear set; And
And an output shaft for transmitting rotational torque to a wheel by coupling a second output gear disposed in engagement with the first output gear.
The method of claim 1,
The first output gear,
A sun gear disposed in the center;
A plurality of planetary gears disposed on the outer circumferential surface of the sun gear so as to mesh with the sun gear;
A ring gear disposed outside the planetary gears so as to mesh with the planetary gears; And,
A transmission for an electric vehicle, characterized in that consisting of a planetary gear set including a;
The method of claim 1,
In the basic mode and the reverse mode, the power transmission gear is a transmission for an electric vehicle, characterized in that the shaft is coupled to the sun gear of the first output gear.
The method of claim 1,
And a second motor connected to the carrier of the first output gear to transmit power in the shift mode.
The method of claim 1,
In the basic mode and the reverse mode, the power transmission gear is a transmission for an electric vehicle, characterized in that connected to the carrier of the first output gear.
The method of claim 1,
And a second motor axially coupled to the sun gear of the first output gear to transmit power in the shift mode.

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