KR102554882B1 - 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 first hollow shaft and a second hollow shaft installed relative to the input shaft to be rotatable; a dual clutch device installed to transmit the power of the input shaft to the first hollow shaft or the second hollow shaft, respectively; an odd-stage driving gear integrally provided on the first hollow shaft and installed to implement an odd-stage among a series of gear shift stages; an even stage driving gear integrally provided on the second hollow shaft and installed to implement an even stage; odd-stage driven gears and even-stage driven gears installed to be relatively rotatable on the output shaft so as to engage with the odd-stage drive gears and the even-stage drive gears, respectively; It is configured to include a plurality of synchronization devices provided on the output shaft to connect or disconnect the odd-stage driven gear and the even-stage driven gear to the output shaft.

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 first hollow shaft and a second hollow shaft installed relative to the input shaft to be rotatable;

a dual clutch device installed to transmit the power of the input shaft to the first hollow shaft or the second hollow shaft, respectively;

an odd-stage driving gear integrally provided on the first hollow shaft and installed to implement an odd-stage among a series of gear shift stages;

an even stage driving gear integrally provided on the second hollow shaft and installed to implement an even stage;

odd-stage driven gears and even-stage driven gears installed to be relatively rotatable on the output shaft so as to engage with the odd-stage drive gears and the even-stage drive gears, respectively;

and a plurality of synchronizing devices provided on the output shaft to connect or disconnect the odd-stage driven gear and the even-stage driven gear to or from the output shaft.

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

The dual clutch device

Receiving linear displacement along the axial direction of the input shaft from the outside, the friction force generated between the first clutch disk installed on the first hollow shaft and the second clutch disk installed on the second hollow shaft changes in proportion to the linear displacement, respectively. a dual clutch configured to;

An actuator installed to provide linear displacement along the axial direction of the input shaft to the dual clutch; may be configured to include.

The actuator

housing department;

a ball screw device provided in the housing to provide linear displacement to the dual clutch by a 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 of the ball nut by interlocking with the rotation of the screw to support a state in which the ball nut advances toward the dual clutch; 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 odd-stage drive gear installed on the first hollow shaft is composed of a first-stage drive gear and a third-stage drive gear;

The even-stage drive gear installed on the second hollow shaft is made of a two-stage drive gear;

On the output shaft, a first-stage driven gear meshed with the first-stage drive gear, a third-stage driven gear meshed with the third-stage drive gear, and a second-stage driven gear meshed with the second-stage drive gear are sequentially disposed;

Between the 1st driven gear and the 3rd driven gear, a 1st & 3rd gear synchronous device connecting or disconnecting the 1st driven gear or 3rd driven gear to the output shaft is installed;

A two-stage synchronous device may be installed next to the second-stage driven gear to connect or block the second-stage driven gear to the output shaft.

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.

Referring to Figures 1 to 12, the embodiment of the present invention receives power from the drive motor shaft (MS) and the drive motor shaft (MS) and the concentric reduction device for outputting the deceleration to the input shaft (IN) forming a concentric axis; an output shaft (OUT) disposed parallel to the input shaft (IN); a first hollow shaft (HS1) and a second hollow shaft (HS2) rotatably installed on the input shaft (IN); a dual clutch device installed to transmit the power of the input shaft (IN) to the first hollow shaft (HS1) or the second hollow shaft (HS2), respectively; an odd-stage driving gear integrally provided on the first hollow shaft (HS1) and installed to implement an odd-stage among a series of shift stages; an even-stage drive gear integrally provided with the second hollow shaft (HS2) and installed to implement an even-stage; odd-stage driven gears and even-stage driven gears installed to be relatively rotatable on the output shaft (OUT) so as to be engaged with the odd-stage drive gears and the even-stage drive gears, respectively; It is configured to include; a plurality of synchronization devices provided on the output shaft (OUT) to connect or disconnect the odd-stage driven gear and the even-stage driven gear to the output shaft (OUT).

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 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, a configuration in which power of the drive motor is decelerated and output through the input shaft IN connected to the carrier can be implemented. .

In this embodiment, the dual clutch device receives linear displacement along the axial direction of the input shaft IN from the outside, and the first clutch disk CD1 installed on the first hollow shaft HS1 and the second hollow shaft a dual clutch (DC) configured such that the frictional force generated in the second clutch disk (CD2) installed in (HS2) varies in proportion to the linear displacement; It is configured to include an actuator (AT) installed to provide linear displacement along the axial direction of the input shaft (IN) to the dual clutch (DC).

The actuator (AT) includes a housing (1); a ball screw device (5) provided in the housing (1) to provide linear displacement to the dual clutch (DC) by the ball nut (3) linearly moving along the direction of the input shaft (IN); a control motor 9 installed in the housing 1 to drive the screw 7 of the ball screw device 5; Includes a self-locking mechanism provided in the housing 1 to prevent reverse movement by interlocking with the rotation of the screw 7 to support the forward state of the ball nut 3 toward the dual clutch DC It is composed by

The self-locking mechanism includes a wedge piston 11 installed in the housing 1 to be linearly movable in a direction perpendicular to the input shaft IN and contacting the rear end of the ball nut 3 with an inclined surface; It is configured to include an interlocking device provided to linearly move the wedge piston 11 by receiving the rotational force of the screw 7.

The interlocking device includes a rack gear 13 formed on the wedge piston 11; a pinion 15 geared to the lacquer 13; It is configured to include an interlocking gear 17 externally meshed with the screw 7 and provided together with the pinion 15 on a rotating shaft of the pinion 15 .

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. Comparing FIGS. 11 and 12, the ball nut 3 moves from the state of FIG. 11 to the state of FIG. 12 to the left in the drawing. It can be seen that linear displacement is provided to the dual clutch DC by forming one linear displacement.

For reference, FIG. 11 can be seen in a state before frictional force is generated in the dual clutch (DC), and FIG. 12 is a state in which frictional force is formed in the dual clutch (DC) by linear displacement provided by the ball nut (3). Can be seen as.

In addition, in FIGS. 11 and 12, the direction in which the ball nut 3 moves to the side where the dual clutch DC is located is referred to as the front, and the opposite direction is referred to as the rear.

In addition, in front of the ball nut 3, a leaf spring 21 is configured to elastically transmit linear displacement to the dual clutch DC through a bearing 19, and in the dual clutch DC, the ball The pressure applied to the first clutch disk CD1 or the second clutch disk CD2 increases according to the linear displacement provided by the nut 3 .

Of course, in order to separately provide the pressure for pressing the first clutch disk CD1 and the pressure for pressing the second clutch disk CD2, the configuration of the actuator AT as described above is provided by overlapping two sets or Two actuators (AT) should be used to provide two independent linear displacements to the dual clutch (DC), but here, for convenience of understanding, a configuration that forms one linear displacement will be described.

In addition, as described above, the configuration of receiving two independent linear displacements from the actuator AT and converting them into frictional force of the first clutch disk CD1 or the second clutch disk CD2 in the dual clutch DC It will be possible to implement by known technology.

In the state of FIG. 11, when the control motor 9 is driven by a controller (not shown), the screw 7 rotates, and the ball nut 3 moves toward the dual clutch DC to move the bearing 19. Through this, the leaf spring 21 is pushed to increase the frictional force of the dual clutch DC.

At this time, when the interlocking gear 17 rotates due to the rotation of the screw 7, the pinion integrally connected thereto rotates, and the wedge piston 11 formed with the rack gear 13 rotates the input shaft as shown in FIG. (IN), the inclined surface formed at the rear end of the ball nut 3 is supported by the inclined surface of the wedge piston 11, so that the ball nut A self-locking function that prevents (3) from moving backward is implemented.

The self-locking function as described above does not require additional power to continuously operate the dual clutch (DC) in a situation where, for example, power is continuously transmitted through the dual clutch (DC), ultimately reducing fuel consumption of an electric vehicle. and improve mileage.

On the other hand, looking at the configuration of the embodiment of FIG. 1 in more detail, the odd-stage drive gear installed on the first hollow shaft (HS1) is composed of a first-stage drive gear (D1) and a third-stage drive gear (D3); The even-stage drive gear installed on the second hollow shaft (HS2) consists of a two-stage drive gear (D2); On the output shaft OUT, the 1st driven gear P1 meshed with the 1st drive gear D1, the 3rd driven gear P3 meshed with the 3rd drive gear D3, and the 2nd drive gear D2. The second driven gear (P2) is arranged sequentially; Between the 1st driven gear P1 and the 3rd driven gear P3, the 1st & 3rd gear synchronous device connecting or disconnecting the 1st driven gear P1 or 3rd driven gear P3 to the output shaft OUT ( 1&3S) is installed; Next to the second-stage driven gear P2, a second-stage synchronous device 2S is installed to connect or disconnect the second-stage driven gear P2 to the output shaft OUT.

Meanwhile, the dual clutch DC is composed of the first clutch CL1 and the second hollow shaft HS2 connecting the first clutch disk CD1 of the first hollow shaft HS1 to the input shaft IN. It can be considered to be composed of a second clutch CL2 connecting the two clutch disks CD2 to the input shaft IN.

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

FIG. 2 shows a state in which the 1st stage driven gear P1 is connected to the output shaft OUT and the first clutch CL1 of the dual clutch DC is connected to prepare for a 1st stage start in the 1&3 synchronizing device from the state of FIG. 1. it is depicted

FIG. 3 is a first-stage drive gear through the first clutch CL1 of the dual clutch DC after the first-stage power is decelerated in the planetary gear device PG by driving the drive motor DM in the state of FIG. 2 ( D1), it is decelerated again in the first-stage driving gear D1 and the first-stage driven gear P1, and drawn out to the driving wheels through the output shaft OUT and the differential DF.

As described above, in the present invention, since the first-stage transmission ratio is implemented by multiplying the gear ratio provided by the planetary gear device PG and the gear ratio provided by the first-stage driving gear D1 and the first-stage driven gear P1, the planetary gear Compared to the case where the first gear ratio is formed only with the gear ratio of the first gear drive gear D1 and the first driven gear P1 without the reduction ratio of the device PG, the size of the first driven gear P1 can be relatively small. It is possible to form a sufficient 1-speed gear ratio while still having it, and the distance between the shafts between the input shaft (IN) and the output shaft (OUT) can be narrowed, thereby reducing the overall weight of the transmission and realizing a relatively high gear ratio. Even when using a drive motor (DM) with a small capacity, it is possible to secure sufficient vehicle climbing performance.

FIG. 4 shows a state in which the second gear driven gear P2 is connected to the output shaft OUT by the second gear synchronous device 2S for shifting to the second gear in the first gear driving situation as shown in FIG. 3 . At this time, the second clutch CL2 of the dual clutch DC is released, and the power of the drive motor DM is transmitted to the output shaft OUT through the second drive gear D2 and the second driven gear P2. It is not passed on.

FIG. 5 shows a situation in which a shift to second gear is performed from the state of FIG. 4 . The first clutch CL1 is released and the second clutch CL2 is engaged at the same time so that the shift to second gear is substantially performed. , and when the gear shift is completed, as shown in FIG. 6, the power of the drive motor DM is transferred to the second clutch CL2, the second drive gear D2, and the second driven gear P2 of the dual clutch DC. ), it becomes a two-stage driving state provided to the output shaft (OUT).

Therefore, as described above, the power from the driving motor DM is continuously transmitted to the output shaft OUT while shifting from 1st gear to 2nd gear, thereby realizing shifting by the conventional synchronous device mechanism. Since the torque interruption phenomenon inevitably occurring during shifting does not occur, a vehicle equipped with the transmission of the present invention can secure a smooth and smooth shifting feeling.

7 shows a state in which the 3rd driven gear P3 is connected to the output shaft OUT by the 1&3 synchronizing device for shifting to 3rd gear, since the first clutch CL1 of the dual clutch DC is still released. The power of the driving motor DM is not transmitted from the input shaft IN to the output shaft OUT through the third driving gear D3 and the third driven gear P3.

FIG. 8 illustrates a process of shifting to third gear, wherein the first clutch CL1 is engaged while the second clutch CL2 of the dual clutch DC is released, and transmission is transmitted to the output shaft OUT during gear shifting. Without interruption of the applied torque, the shift to the third gear is completed by transitioning to the state shown in FIG. 9 .

FIG. 10 shows a state in which a reverse shift stage is implemented, structurally the same as that of FIG. 4 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 transmission for an electric vehicle according to the present invention is formed by the concentric reduction device, the first-stage drive gear (D1), and the first-stage driven gear (P1), so the volume and weight of the transmission can be reduced, and the gear ratio is relatively large. As a result, it is possible to secure sufficient climbing performance of the vehicle with a relatively small capacity of the drive motor (DM), and to provide a relatively large number of gear stages for an electric vehicle that reaches 3 forward stages, thereby providing sufficient acceleration performance and maximum speed of the vehicle. to be able to secure it.

Meanwhile, FIG. 13 shows another embodiment of the present invention, in which the 3rd drive gear D3 and the 3rd driven gear P3 are removed from the configuration of FIG. 1 to implement a total of 2 forward gears. An example of configuring a two-speed transmission is shown, 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; housing
3; ball nut
5; ball screw device
7; screw
9; control motor
11; wedge piston
13; rack gear
15; pinion
17; interlocking gear
19; bearing
21; leaf spring
MS; drive motor shaft
IN; input shaft
OUT; output shaft
HS1; 1st hollow shaft
HS2; 2nd hollow shaft
D-F; differential
OG; output gear
PG; planetary gear
CD1; 1st clutch disk
CD2; 2nd clutch disk
DC; dual clutch
AT; actuator
D1; 1st drive gear
D3; 3-speed drive gear
D2; 2nd stage drive gear
P1; 1st driven gear
P3; 3-stage driven gear
P2; 2nd driven gear
1&3S;1&3 single synchronous device
2S; 2-speed synchroniser
CL1; 1st clutch
CL2; 2nd clutch
DM; drive motor

Claims (7)

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 first hollow shaft and a second hollow shaft installed relative to the input shaft to be rotatable;
a dual clutch device installed to transmit the power of the input shaft to the first hollow shaft or the second hollow shaft, respectively;
an odd-stage drive gear integrally provided on the first hollow shaft and installed to realize an odd-stage among a series of gear shift stages;
an even-stage drive gear integrally provided on the second hollow shaft and installed to implement an even-stage;
odd-stage driven gears and even-stage driven gears installed to be relatively rotatable on the output shaft so as to engage with the odd-stage drive gears and the even-stage drive gears, respectively;
a plurality of synchronizing devices provided on the output shaft to connect or disconnect the odd-stage driven gear and the even-stage driven gear to or from the output shaft;
It is composed of,
The dual clutch device
Receiving linear displacement along the axial direction of the input shaft from the outside, the friction force generated between the first clutch disk installed on the first hollow shaft and the second clutch disk installed on the second hollow shaft changes in proportion to the linear displacement, respectively. a dual clutch configured to;
an actuator installed to provide linear displacement along the axial direction of the input shaft to the dual clutch;
It consists of,
The actuator
housing department;
a ball screw device provided in the housing to provide linear displacement to the dual clutch by a 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 dual clutch;
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. 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 5,
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 6,
The odd-stage drive gear installed on the first hollow shaft is composed of a first-stage drive gear and a third-stage drive gear;
The even-stage drive gear installed on the second hollow shaft is made of a two-stage drive gear;
On the output shaft, a first-stage driven gear meshed with the first-stage drive gear, a third-stage driven gear meshed with the third-stage drive gear, and a second-stage driven gear meshed with the second-stage drive gear are sequentially disposed;
Between the 1st driven gear and the 3rd driven gear, a 1st & 3rd gear synchronous device connecting or disconnecting the 1st driven gear or 3rd driven gear to the output shaft is installed;
Next to the second-stage driven gear, a second-stage synchronous device for connecting or blocking the second-stage driven gear to the output shaft is installed.
A transmission for electric vehicles characterized by a.

Images