KR102554941B1 - Transmission for electric vehicle - Google Patents

Abstract

The present invention includes a concentric reduction device for receiving power from a drive motor shaft and decelerating and outputting power to an input shaft concentric with the drive motor shaft; an output shaft disposed parallel to the input shaft; a plurality of transmission gear pairs installed on the input shaft and the output shaft to be externally engaged to form different transmission ratios; a first clutch means provided to switch between a state in which the transmission gear pair transmits power from the input shaft to an output shaft and a state in which power is blocked; It is configured to include; a second clutch means provided to transmit the power of the input shaft to the output shaft by continuously variable frictional force.

Description

Transmission for electric vehicle {TRANSMISSION FOR ELECTRIC VEHICLE}

The present invention relates to a transmission for an electric vehicle, and more particularly, to a technology for configuring a powertrain capable of ensuring sufficient driving performance of a vehicle while using a drive motor with as little capacity as possible.

An electric vehicle uses a drive motor to provide the driving force necessary for driving the vehicle instead of an engine. The price of the drive motor generally increases in proportion to the capacity or size, and when the size of the drive motor increases, the driving force that can be provided Although the range of is widened, it is also a factor that lowers the fuel efficiency due to the increase in the weight of the vehicle.

The matters described as the background technology of the present invention are only for the purpose of improving the understanding of the background of the present invention, and should not be taken as an admission that they correspond to the prior art already known to those skilled in the art. It will be.

KR 1020170018220 A

The present invention ensures sufficient driving performance such as maximum speed, acceleration performance, and climbing performance of the vehicle while using a drive motor of as small a capacity as possible, thereby reducing the cost required for manufacturing the vehicle and securing the required driving performance of the vehicle The purpose is to provide a transmission for electric vehicles that can ultimately maximize the marketability of vehicles.

Transmission for an electric vehicle of the present invention for achieving the above object

a concentric reduction device for receiving power from the drive motor shaft and decelerating the power to an input shaft concentric with the drive motor shaft;

an output shaft disposed parallel to the input shaft;

a plurality of transmission gear pairs installed on the input shaft and the output shaft to be externally engaged to form different gear ratios;

a first clutch means provided to switch between a state in which the transmission gear pair transmits power from the input shaft to an output shaft and a state in which power is blocked;

It is characterized in that it is configured to include a; second clutch means provided to continuously and variably transfer the power of the input shaft to the output shaft by frictional force.

The concentric reduction device may be composed of a single pinion planetary gear device in which a ring gear is always fixed.

The first clutch means may be composed of a synchronizing device that is synchronized by frictional force and then meshed to form a state in which power is transmitted.

The second clutch means is

a driving gear rotatably installed on the input shaft;

a driven gear installed on the output shaft in a state meshed with the driving gear;

a friction clutch provided to vary and transmit power by varying the frictional force formed in the clutch disk provided between the input shaft and the driving gear;

an actuator provided to adjust the frictional force of the friction clutch;

It can be configured to include.

The actuator

housing department;

a ball screw device provided in the housing to adjust the pressure applied to the clutch disk by the ball nut linearly moving along the direction of the input shaft;

a control motor installed in the housing to drive the screw of the ball screw device;

A self-locking mechanism provided in the housing to prevent reverse movement by interlocking with the rotation of the screw to support the forward state of the ball nut toward the clutch disk; may be configured to include.

The self-locking mechanism

a wedge piston installed in the housing to be linearly movable in a direction perpendicular to the input shaft and contacting the rear end of the ball nut with an inclined surface;

It may be configured to include; an interlocking device provided to linearly move the wedge piston by receiving the rotational force of the screw.

The interlocking device

a rack gear formed on the wedge piston;

a pinion meshed with the rack gear;

It may be configured to include; an interlocking gear externally meshed with the screw and provided with the pinion on a rotating shaft of the pinion.

The plurality of transmission gear pairs are composed of a first-speed gear pair implementing the largest transmission ratio and a second-speed transmission gear pair implementing a smaller transmission ratio than the first-speed transmission gear pair;

The first clutch means is installed on the input shaft and consists of 1 & 2 synchronizing devices for transmitting power from the input shaft to the 1st gear pair and to the 2nd gear pair and to realize a neutral state;

The driving gear and the driven gear of the second clutch unit may be configured to realize a gear ratio smaller than that of the second gear pair.

The present invention ensures sufficient driving performance such as maximum speed, acceleration performance, and climbing performance of the vehicle while using a drive motor of as small a capacity as possible, thereby reducing the cost required for manufacturing the vehicle and securing the required driving performance of the vehicle Thus, ultimately, the marketability of the vehicle can be maximized.

1 is a view showing the structure of a transmission for an electric vehicle according to the present invention;
2 to 10 are views explaining the operation of the transmission of FIG. 1;
11 is a detailed configuration diagram of the actuator of FIG. 1;
12 is a view explaining the operation of the actuator compared to the structure of FIG. 11;
13 is a diagram showing another embodiment of the present invention.

1 to 12, an embodiment of the transmission for an electric vehicle of the present invention receives power from a drive motor shaft (MS) and decelerates it to an input shaft (IN) concentric with the drive motor shaft (MS) and outputs it. a concentric deceleration device; an output shaft (OUT) disposed parallel to the input shaft (IN); a plurality of transmission gear pairs installed on the input shaft (IN) and the output shaft (OUT) to be externally engaged to form different gear ratios; a first clutch means provided to switch between a state in which the transmission gear pair transmits the power of the input shaft (IN) to an output shaft (OUT) and a state in which power is blocked; It is configured to include a second clutch means provided to continuously and variably transfer the power of the input shaft (IN) to the output shaft (OUT) by frictional force.

An output gear OG connected to the differential DF is integrally provided on the output shaft OUT so that power transmitted from the input shaft IN can be distributed to both driving wheels through the differential DF.

In this embodiment, the concentric reduction device is composed of a single pinion planetary gear device (PG) in which the ring gear is always fixed. More specifically, the power of the drive motor (DM) is input to the drive motor shaft (MS) connected to the sun gear of the planetary gear device (PG), and is decelerated and output to the input shaft (IN) connected to the carrier.

Of course, even if the sun gear of the planetary gear device (PG) is fixed and the drive motor shaft (MS) is connected to the ring gear, the power of the drive motor (DM) is reduced and output through the input shaft (IN) connected to the carrier. can be implemented

In this embodiment, the first clutch means is composed of a synchronization device that is synchronized by frictional force and then meshed to form a state in which power is transmitted.

Of course, the first clutch means may also be configured as a dog clutch or a magnet clutch.

In this embodiment, the second clutch means includes a drive gear (1) installed rotatably relative to the input shaft (IN); a driven gear 3 installed on the output shaft OUT in a state meshed with the drive gear 1; a friction clutch (BC) provided to vary and transmit power by varying the frictional force formed in the clutch disk (5) provided between the input shaft (IN) and the drive gear (1); It is configured to include an actuator (AT) provided to adjust the frictional force of the friction clutch (BC).

The actuator (AT) includes a housing (7); a ball screw device 11 provided in the housing 7 to adjust the pressure applied to the clutch disk 5 by the ball nut 9 linearly moving along the input shaft IN direction; a control motor 15 installed in the housing 7 to drive the screw 13 of the ball screw device 11; Includes a self-locking mechanism provided in the housing 7 to prevent reverse movement by interlocking with the rotation of the screw 13 to support the forward state of the ball nut 9 toward the clutch disk 5 It is composed by

The self-locking mechanism includes a wedge piston 17 installed in the housing 7 to be linearly movable in a direction perpendicular to the input shaft IN and contacting the rear end of the ball nut 9 with an inclined surface; It is configured to include an interlocking device provided to linearly move the wedge piston 17 by receiving the rotational force of the screw 13.

In this embodiment, the interlocking device includes a rack gear 19 integrally formed with the wedge piston 17; a pinion 21 geared to the lacquer 19; It is configured to include an interlocking gear 23 externally meshed with the screw 13 and provided along with the pinion 21 on a rotating shaft of the pinion 21 .

In addition to the interlocking device, it may be implemented using a power transmission device such as a belt or chain.

11 and 12 compare and explain the structure and operation of the actuator AT, and comparing FIGS. 11 and 12, the ball nut 9 moves from the state of FIG. 11 to the state of FIG. 12 to the left in the drawing. It can be seen that the moving linear displacement is formed and provided to the friction clutch BC.

For reference, FIG. 11 can be seen in a state before frictional force is generated in the friction clutch (BC), and FIG. 12 is in a state in which frictional force is formed in the friction clutch (BC) by the linear displacement provided by the ball nut (9). can see.

In addition, in FIGS. 11 and 12, the direction in which the ball nut 9 moves to the side where the friction clutch BC is located is referred to as the forward direction, and the opposite direction is referred to as the rear direction.

In addition, in front of the ball nut 9, a leaf spring 27 is configured to elastically transmit linear displacement to the friction clutch BC through a bearing 25, and in the friction clutch BC, the ball It is configured so that the pressure applied to the clutch disk 5 increases according to the linear displacement provided by the nut 9, and as a result, the amount of power transmitted to the driving gear 1 of the input shaft IN is adjusted. .

In the state of FIG. 11, when the control motor 15 is driven by a controller (not shown), the screw 13 rotates, and the ball nut 9 moves toward the friction clutch BC to move the bearing 25. Through this, the leaf spring 27 is pushed to increase the frictional force of the friction clutch BC.

At this time, when the interlocking gear 23 rotates due to the rotation of the screw 13, the pinion 21 integrally connected thereto rotates, and the wedge piston 17 on which the rack gear 19 is formed rotates. It moves vertically toward the input shaft (IN), and the inclined surface formed at the rear end of the ball nut 9 is supported by the inclined surface of the wedge piston 17, even if power is not supplied to the control motor 15. A self-locking function that prevents the ball nut 9 from moving backward is implemented.

The self-locking function as described above does not require additional power to continuously operate the friction clutch BC in a situation where, for example, power is continuously transmitted through the friction clutch BC, ultimately fuel efficiency of the electric vehicle. and improve mileage.

On the other hand, looking at the configuration of the embodiment of FIG. 1 in more detail, the plurality of transmission gear pairs are a first gear pair (SG1) that implements the largest gear ratio, and a second gear pair that implements a smaller gear ratio than the first gear pair (SG1). It consists of a single shift gear pair (SG2); The first clutch means is installed on the input shaft (IN) and transmits the power of the input shaft (IN) to the first gear pair (SG1) and the second gear pair (SG2) and a neutral state. It is composed of 1&2 synchronizer (1&2S) that implements; The driving gear 1 and the driven gear 3 of the second clutch means are configured to realize a gear ratio smaller than that of the second gear pair SG2.

Therefore, as a result, the transmission ratio formed by the drive gear 1 and the driven gear 3 implements the transmission ratio of the three stages.

The operation of the transmission configured as described above will be reviewed through FIGS. 2 to 10 .

FIG. 2 moves the sleeve of the 1&2 synchronous device (1&2S) to the left from the neutral state of FIG. 1 for first-speed driving, and the power of the input shaft (IN) is transmitted to the output shaft (OUT) through the first-stage gear pair (SG1). It is a condition that can be transmitted.

FIG. 3 shows a state in which the drive motor is driven from the state of FIG. 2 and the first-stage power is decelerated in the planetary gear device and then decelerated in the first-stage transmission gear pair (SG1) and is drawn to the driving wheels through the output shaft and the differential. will be.

As such, in the present invention, since the first gear ratio is implemented by multiplying the gear ratio provided by the planetary gear unit and the gear ratio provided by the first gear pair SG1, the gear ratio of the first gear pair without the reduction ratio of the planetary gear unit Compared to the case where the first gear ratio is formed only by the gearbox, the size of the first gear pair can be relatively small, and a sufficient first gear ratio can be formed, thereby narrowing the distance between the shafts between the input shaft and the output shaft. The overall weight of the vehicle is reduced, and a relatively high transmission ratio can be implemented, so that sufficient vehicle climbing performance can be secured even when a drive motor with a relatively small capacity is used.

FIG. 4 shows operating the friction clutch BC of the second clutch means to shift to second gear in the first gear driving situation as shown in FIG. 3 . Of course, this means that the controller drives the actuator AT so that frictional force is generated in the friction clutch BC, and the amount of power transmitted through the friction clutch BC varies depending on the driving amount of the actuator AT. .

In this state, the power from the drive motor DM is transmitted to the output shaft OUT through the first gear shift gear pair SG1, and the friction clutch BC, the driving gear 1, and the driven gear 3 are transmitted. transmitted in parallel through

5 shows that the 1&2 synchronous device 1&2S is released to the neutral state from the state of FIG. 4, but the power of the driving motor DM continues to drive the friction clutch BC, the drive gear 1 and the driven gear 3. It indicates the status being transmitted to the output shaft (OUT) through .

6 shows that the sleeve of the 1&2 synchronous device 1&2S moves to the right from the state of FIG. 5 so that the power of the input shaft IN is transmitted to the output shaft OUT through the second gear pair SG2. However, power is still being transmitted through the second clutch means.

FIG. 7 reversely drives the actuator AT from the state of FIG. 6 so that the friction clutch BC is released, so that the power of the drive motor DM is output only through the second gear pair SG2. OUT) represents a true two-stage state.

That is, the states of FIGS. 4 to 6 are a series of processes in which the shift is performed while the power is continuously transmitted to the output shaft OUT during the shift from the 1st driving state in FIG. 3 to the 2nd driving state in FIG. 7 . will represent

As described above, by continuously transmitting power from the drive motor DM to the output shaft OUT while shifting from 1st gear to 2nd gear, gear shifting is performed by a synchronizing mechanism such as the conventional 1&2 synchronizing device (1&2S). A vehicle equipped with the transmission of the present invention can secure a smooth and smooth shifting feeling because the torque interruption phenomenon during gear shifting, which inevitably occurs in a transmission implementing the above, does not occur.

8 illustrates a situation in which the friction clutch BC is operated for shifting from a 2-speed driving situation to a 3-speed gear, and the power of the drive motor DM is supplied with the 2-speed gear pair SG2. It is a state in which it is transmitted to the output shaft OUT through the drive gear 1 and the driven gear 3.

FIG. 9 shows that the 1&2 synchronizing devices 1&2S are released to a neutral state from the state of FIG. 8, and the power of the driving motor DM drives the friction clutch BC, the driving gear 1, and the driven gear 3. It shows a state in which transmission is transmitted to the output shaft OUT while forming a 3-speed shift stage through the

As described above, torque interruption does not occur even in the process of shifting from the second gear to the third gear, and a smooth shift feeling can be secured.

FIG. 10 shows a state in which a reverse shift stage is implemented, structurally the same as that of FIG. 3 in which the first stage is implemented, but the reverse shift stage is implemented by rotating the drive motor DM in reverse.

As described above, the electric vehicle transmission according to the present invention is formed by a concentric reduction device and a first-speed gearbox, so the volume and weight of the transmission can be reduced, while securing a relatively large transmission ratio and a relatively small capacity of a drive motor. It is to ensure sufficient climbing performance of the vehicle, and to provide a relatively large number of gear stages for an electric vehicle that reaches three forward stages, so that the acceleration performance and maximum speed of the vehicle can be sufficiently secured.

Meanwhile, FIG. 13 shows another embodiment of the present invention, in which a two-speed transmission capable of realizing a total of two forward gears by removing the two-speed gear pair SG2 from the configuration of FIG. 1 is an example of configuration. , and its operation is almost the same as that of the above embodiment.

Although the present invention has been shown and described in relation to specific embodiments, it is known in the art that the present invention can be variously improved and changed without departing from the technical spirit of the present invention provided by the claims below. It will be self-evident to those skilled in the art.

One; driving gear
3; driven gear
5; clutch disc
7; housing
9; ball nut
11; ball screw device
13; screw
15; control motor
17; wedge piston
19; rack gear
21; pinion
23; interlocking gear
25; bearing
27; leaf spring
MS; drive motor shaft
IN; input shaft
OUT; output shaft
D-F; differential
OG; output gear
PG; planetary gear
DM; driving motor
BC; friction clutch
AT; actuator
SG1; 1 gear shift gear pair
SG2; 2-speed gearbox pair
1&2S;1&2 Synchronizer

Claims (8)

a concentric reduction device for receiving power from the drive motor shaft and decelerating the power to an input shaft concentric with the drive motor shaft;
an output shaft disposed parallel to the input shaft;
a plurality of transmission gear pairs installed on the input shaft and the output shaft to be externally engaged to form different gear ratios;
a first clutch means provided to switch between a state in which the transmission gear pair transmits power from the input shaft to an output shaft and a state in which power is blocked;
a second clutch means provided to continuously and variably transmit power from the input shaft to the output shaft by frictional force;
It is composed of,
The second clutch means is
a driving gear rotatably installed on the input shaft;
a driven gear installed on the output shaft in a state meshed with the driving gear;
a friction clutch provided to vary and transmit power by varying the frictional force formed in the clutch disk provided between the input shaft and the driving gear;
an actuator provided to adjust the frictional force of the friction clutch;
It consists of,
The actuator
housing department;
a ball screw device provided in the housing to adjust the pressure applied to the clutch disk by the ball nut linearly moving along the direction of the input shaft;
a control motor installed in the housing to drive the screw of the ball screw device;
a self-locking mechanism provided in the housing to prevent reverse movement by interlocking with the rotation of the screw to support the forward state of the ball nut toward the clutch disk;
A transmission for an electric vehicle, characterized in that configured to include a. The method of claim 1,
The concentric reduction device is composed of a single pinion planetary gear device in which the ring gear is always fixed.
A transmission for electric vehicles characterized by a. The method of claim 1,
The first clutch means is composed of a synchronization device that is synchronized by frictional force and then meshed to form a state in which power is transmitted.
A transmission for electric vehicles characterized by a. delete delete The method of claim 1,
The self-locking mechanism
a wedge piston installed in the housing to be linearly movable in a direction perpendicular to the input shaft and contacting the rear end of the ball nut with an inclined surface;
an interlocking device provided to linearly move the wedge piston by receiving the rotational force of the screw;
A transmission for an electric vehicle, characterized in that configured to include a. The method of claim 6,
The interlocking device
a rack gear formed on the wedge piston;
a pinion meshed with the rack gear;
an interlocking gear circumscribed to the screw and provided along with the pinion on a rotating shaft of the pinion;
A transmission for an electric vehicle, characterized in that configured to include a. The method of claim 7,
The plurality of transmission gear pairs are composed of a first-speed gear pair that implements the largest transmission ratio and a second-speed transmission gear pair that implements a smaller transmission ratio than the first-speed gear pair;
The first clutch means is installed on the input shaft and consists of 1 & 2 synchronizing devices that implement a state in which the power of the input shaft is transmitted to the first gear pair, a state in which power is transmitted to the second gear pair, and a neutral state;
The driving gear and the driven gear of the second clutch means are configured to realize a gear ratio smaller than that of the second gear shift gear pair.
A transmission for electric vehicles characterized by a.

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