KR20200117087A - Shift system and control method for electric vehicle - Google Patents

Abstract

The present invention relates to a shift system including: an input shaft connected to a motor through a main clutch; an output shaft arranged parallel to the input shaft; a shift module installed to implement shifting between a plurality of shift gears in a synchro-mesh method between the input shaft and the output shaft; a clutch actuator installed to drive the main clutch; an operating force transmission mechanism provided to transmit driver′s shifting operating force to the shifting module in a mechanical linear displacement; and a controller provided to drive the clutch actuator according to the driver′s shift operation.

Description

Electric vehicle transmission system and its control method {SHIFT SYSTEM AND CONTROL METHOD FOR ELECTRIC VEHICLE}

The present invention is a technology related to the configuration of a transmission system that allows the power of a motor that exhibits a driving force in an electric vehicle to be properly shifted and transmitted to a driving wheel.

Vehicles should be designed to meet the maximum grade performance and maximum vehicle speed performance.In the case of an electric vehicle that uses one motor as the vehicle's power source, using a transmission rather than driving the vehicle with only a motor guarantees the efficiency of the motor. It is advantageous to meet the maximum grade performance and the highest vehicle speed performance.

In the case of installing a transmission in an electric vehicle, the motor can provide the required driving power of the vehicle in a relatively wide range without a significant decrease in efficiency compared to the engine, and the weight and cost aspects compared to the effect of the increase in the number of shift stages. In consideration, it is preferable to configure the number of shift stages into 2 to 3 gears.

Conventional electric vehicle transmissions do not use a torque converter between the motor and transmission in order to improve fuel efficiency (electricity) of the electric vehicle, and use a transmission mechanism with high power transmission efficiency similar to that of a conventional manual transmission, but are similar to conventional automatic transmission vehicles In order to realize a smooth shifting feeling that prevents the user from recognizing the shift, it is mainly in the direction of allowing automatic shifting without the main clutch between the motor and the transmission causing torque interruption. Is being developed.

However, as described above, in order to provide a transmission ratio suitable for a wide speed range of a vehicle with a small number of transmission stages of 2nd to 3rd, the gear ratio must be larger than that of a conventional transmission. Since it is a factor that causes a greater impact, it is difficult to develop a practical electric vehicle transmission.

The matters described as the background technology of the present invention are only for enhancing an understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art. Will be

KR 1020160024077 A

The present invention provides a plurality of shift stages to sufficiently secure the maximum climbing capability and maximum vehicle speed performance of the vehicle, and improves the fuel consumption of the vehicle by utilizing the efficient driving point of the motor during high-speed driving of the vehicle. Noise and vibration characteristics can be improved by reducing the rotation speed, and based on the same power performance, the capacity and weight of the motor can be significantly reduced compared to electric vehicles implemented only with a motor, and the driver feels an unexpected shifting action. It is an object of the present invention to provide a transmission system for electric vehicles and a control method thereof so as not to be dissatisfied by the problem.

The transmission system for an electric vehicle of the present invention for achieving the above object,

An input shaft connected to the motor through the main clutch;

An output shaft disposed parallel to the input shaft;

A shift module installed between the input shaft and the output shaft to implement shifting between a plurality of shift stages in a synchronous mesh manner;

A clutch actuator installed to drive the main clutch;

An operating force transmission mechanism provided to transmit the shifting operating force of a driver to the shifting module in a mechanical linear displacement;

A controller provided to drive the clutch actuator according to the driver's shift operation;

It characterized in that it is configured to include.

The shifting module is

A first-stage driving gear and a first-stage driven gear having the largest transmission ratio meshed with each other;

A three-speed drive gear and a three-speed driven gear meshed with each other with the smallest transmission ratio;

A two-stage driving gear and a two-stage driven gear engaged with each other to have a transmission ratio between the first and third stages;

A first synchronization device installed to implement a first stage;

A second synchronization device installed to selectively implement the second and third stages;

It can be configured to include.

The operation force transmission mechanism

A control finger installed to be movable in the selecting direction and the shifting direction by the driver's shift lever operation force;

A first shift rail installed to transmit an operating force from the control finger to the first synchronous device;

A second shift rail installed to transmit an operating force from the control finger to the second synchronous device;

A first lug and a second lug installed to transmit an operating force of the control finger in a shifting direction to the first and second shift rails, respectively;

It can be configured to include.

The control finger, the first lug, and the second lug may be configured to implement a parking state of the vehicle by simultaneously moving the first shift rail and the second shift rail in a shifting direction.

The control finger moves together in a state in which the first finger for pushing the first lug in the shifting direction and the second finger for pushing the second lug in the shifting direction are spaced apart wider than the thickness of the first finger in the selecting direction Configured to be;

The second lugs are aligned adjacent to the first lug in the selecting direction in a neutral state, and are formed thicker than the thickness of the first lug in the selecting direction, so that the first finger moves the first lug in the shifting direction. When pushing, the second finger may be configured to push the second lug together in a shifting direction.

A first solenoid actuator provided to limit transmission of an operating force for implementing the first stage to the first synchronous device;

A second solenoid actuator provided to limit transmission of the operating force for implementing the second stage to the second synchronous device;

Including more,

The controller controls the first solenoid actuator according to a predetermined first vehicle speed condition to limit the shift from second to first stage, and controls the second solenoid actuator according to a predetermined second vehicle speed condition to control the third stage. It may be configured to limit the shift from the third gear to the first gear by controlling the first solenoid actuator according to a predetermined third vehicle speed condition and to limit the shift from the third gear to the first gear.

When the shifting module is shifted, the controller releases the previous gear, engages the target gear, and then gradually engages the main clutch through slip control, and controls the torque of the motor to maintain the target speed of the motor. Can be configured to

The controller may be configured to release the main clutch with the clutch actuator when detecting a risk of sudden change in motor rotation due to a driver's misoperation.

In addition, the electric vehicle transmission system control method according to the present invention,

When the shifting module is shifted, the previous gear is released, the target gear is engaged, the main clutch is slip-controlled to gradually engage, and the torque of the motor may be controlled to maintain the target speed of the motor.

When there is a risk of sudden change in motor rotation due to a driver's misoperation, the main clutch can be immediately released by the clutch actuator.

The present invention provides a plurality of shift stages to sufficiently secure the maximum climbing capability and maximum vehicle speed performance of the vehicle, and improves the fuel consumption of the vehicle by utilizing the efficient driving point of the motor during high-speed driving of the vehicle. Noise and vibration characteristics can be improved by reducing the rotational speed, and based on the same power performance, the capacity and weight of the motor can be significantly reduced compared to an electric vehicle implemented only with a motor, allowing an economical electric vehicle powertrain to be constructed.

In addition, the present invention prevents the driver from complaining that the driver feels an unexpected shifting action as the driver directly changes the speed according to his or her own intention, and the safety of the vehicle is improved against the driver's incorrect shift lever operation. To secure it.

1 is a configuration diagram of a transmission system for an electric vehicle according to the present invention,
2 is a view showing a simplified example of the transmission configuration of the transmission system for an electric vehicle according to the present invention,
FIG. 3 is a view showing the configuration of FIG. 2 by adding an operation force transmission mechanism for transmitting the driver's shift operation force;
4 is a view showing an example of adding a first solenoid actuator and a second solenoid actuator to the configuration of FIG. 3;
FIG. 5 is a graph illustrating a motor torque according to a motor speed in a transmission system for an electric vehicle according to the present invention, and a driving line for each shift stage, and is a diagram illustrating a first vehicle speed condition, a second vehicle speed condition, and a third vehicle speed condition ,
6 is a diagram illustrating a method for controlling a transmission system for an electric vehicle according to the present invention, and a graph illustrating a shift process from first to second gear and from second to first gear;
7 is a flow chart showing an embodiment of a method for controlling a transmission system for an electric vehicle according to the present invention.

1 and 2, the present invention includes an input shaft IN connected through a motor M and a main clutch CL; An output shaft (OUT) arranged parallel to the input shaft; A shift module (SM) installed to implement shifting between a plurality of shift stages in a synchro-mesh method between the input shaft and the output shaft; A clutch actuator (CA) installed to drive the main clutch (CL); An operation force transmission mechanism provided to transmit the driver's shift operation force to the shift module SM in a mechanical linear displacement; And a controller CLR provided to drive the clutch actuator CA according to the driver's shift operation.

That is, the present invention transmits the power of the motor M to the input shaft IN of the transmission TM equipped with the transmission module SM through the main clutch CL, and the controller (CLR) drives the clutch actuator (CA) to release the main clutch (CL), and the operation force transmission mechanism transmits the driver's shift operation force to the shift module (SM) in a linear displacement so that the shift is made. It is composed.

Therefore, the driver shifts through his own shifting operation, compared to other conventional automatic transmissions that perform the shifting so that the driver is not aware of it, and thus torque interruption occurs due to the release of the main clutch during shifting. Also, they do not take this as a complaint, but take it for granted.

In addition, when shifting is performed while the main clutch CL is released as described above, there is an advantage of being able to perform shifting while minimizing shift shock and relatively easy shifting between shift stages having a relatively large step-to-step ratio.

The transmission module SM includes a first-stage driving gear (1D) and a first-stage driven gear (1P) having the largest transmission ratio meshed with each other; A three-stage drive gear (3D) and a three-stage driven gear (3P) meshed with each other with the smallest transmission ratio; A two-stage drive gear (2D) and a two-stage driven gear (2P) engaged with each other to have a transmission ratio between the first and third gears; A first synchronization device (S1) installed to implement a first stage; It is configured to include a second synchronization device (S2) installed to selectively implement the second and third stages.

That is, a series of shift stages of 1st to 3rd gears are provided, and the 1st gear has the largest transmission ratio and gradually becomes smaller so that the 3rd gear has the minimum transmission ratio, and the 1st synchronous device S1 is in one direction. It is configured to move to and implement the first stage, and the second synchronization device S2 is configured to move in both directions to implement the second and third stages, respectively.

For reference, in the drawings of the present invention, the first gear means the gear level responsible for the lowest vehicle speed, L gear, and the third gear means the gear level responsible for the highest vehicle speed. It is also expressed as D-level in the sense of.

In addition, as shown in FIG. 1, in the present invention, the driver's operation force is transmitted through the shift lever LV, and the shift lever LV is formed to implement the P gear for parking in addition to the L, D, and H gears. It is installed so that it can be manipulated according to the pattern.

Of course, the shift lever LV may be configured to move according to a pattern in which the L, D, H, and P stages are arranged differently.

For reference, it is configured to draw the power of the output shaft OUT to the driving wheel W through the output gear OG and the differential DF.

The operation force transmission mechanism includes a control finger (CF) installed to be movable in a selecting direction and a shifting direction by a driver's shift lever (LV) operation force; A first shift rail (SL1) installed to transmit the operating force from the control finger (CF) to the first synchronous device (S1); A second shift rail (SL2) installed to transmit the operation force from the control finger (CF) to the second synchronous device (S2); It comprises a first lug (L1) and a second lug (L2) installed to transmit the operating force of the control finger (CF) in the shifting direction to the first shift rail (SL1) and the second shift rail (SL2), respectively. .

For reference, the selecting direction and the shifting direction are usually set to be orthogonal, and the selecting direction refers to a linear direction in which the shift lever moves to a position immediately before selecting any of the L, H, D, and P stages. , The shifting direction refers to a direction in which the shift lever moves so as to directly engage the selected shift stage after the shift lever moves by selecting a desired shift stage along the selecting direction.

The operation force of the shift lever LV as described above is transmitted to the first lug L1 and the second lug L2, which are shift lugs, through the control finger CF, and the first lug L1 is the Since the first shift rail (SL1) is fixed and the second lug (L2) is fixed to the second shift rail (SL2), when the control finger (CF) transmits the operating force to the first lug (L1) , When the first shift rail SL1 moves in its longitudinal direction, and the control finger CF transmits an operating force to the second lug L2, the second shift rail SL2 moves in its longitudinal direction. It is configured to move.

A first shift fork SF1 is coupled to the first shift rail SL1 to move the first synchronous device S1 in a linear direction, and a second shift for the second shift rail SL2 The fork SF2 is coupled to be configured to move the second synchronous device S2 in a linear direction.

In the present invention, the control finger CF, the first lug L1, and the second lug L2 move the first shift rail SL1 and the second shift rail SL2 in the shifting direction at the same time, It is configured to implement a parking state.

That is, the control finger CF includes a first finger F1 for pushing the first lug L1 in the shifting direction and a second finger F2 for pushing the second lug L2 in the shifting direction. It is configured to move together in a state spaced apart wider than the thickness of the first finger F1 in the ting direction;

The second lug L2 is aligned adjacent to the first lug L1 in a selecting direction in a neutral state, and is formed thicker than a thickness of the first lug L1 in the selecting direction, so that the first finger When (F1) pushes the first lug L1 in the shifting direction, the second finger F2 is configured to push the second lug L2 together in the shifting direction.

Accordingly, when the control finger CF pushes the first lug L1 and the second lug L2 to the left at the same time as in the PN state of FIG. 3, the first synchronization device S1 and the second synchronization device S2 ) Simultaneously engages 1st and 3rd gears, the shifting module SM of the transmission TM is locked in a state in which it is impossible to transmit rotational force between the motor M and the driving wheel W, and as a result, the vehicle is parked. The state is implemented.

On the other hand, in the HND state of FIG. 3, when the control finger CF is moved to the left, the third stage H is formed, and when it is moved to the right, the second stage and the D stage are formed, and in the LN state, the control finger CF If) is moved to the left, the first stage, L stage is formed.

Referring to FIG. 4, the present invention relates to a first solenoid actuator (SA1) provided to limit the transfer of the operating force to implement the first stage to the first synchronous device (S1); It further includes a second solenoid actuator (SA2) provided to limit the transmission of the operating force to implement the second stage (S2) to the second synchronous device (S2).

In addition, the controller CLR controls the first solenoid actuator SA1 according to a predetermined first vehicle speed condition V1 to limit a shift from the second stage to the first stage, and a predetermined second vehicle speed condition ( The second solenoid actuator (SA2) is controlled according to V2) to limit the shift from the third to the second, and the first solenoid actuator is controlled according to a predetermined third vehicle speed condition (V3) to control the first solenoid actuator to be 1 It is configured to limit the shift to the stage.

That is, the controller drives the first solenoid actuator (SA1) or the second solenoid actuator (SA2) to inhibit the movement of the first shift rail (SL1) or the second shift rail (SL2), thereby limiting the speed change. Is to do.

The first vehicle speed condition V1, the second vehicle speed condition V2, and the third vehicle speed condition V3 are illustrated in FIG. 5.

In other words, the first vehicle speed condition is that if a shift is made to the first gear, L gear, while driving to the current 2nd gear, D gear, the number of rotations of the motor M rapidly rises above the allowable speed of the transmission, causing an unreasonable effect on the powertrain system including the motor. It is set as the vehicle speed at which the durability may be deteriorated and noise and vibration begin to increase relatively rapidly, and the second vehicle speed condition and the third vehicle speed condition are similarly set to the motor when shifting from 3rd to 2nd gear. The number of revolutions is set to a speed capable of preventing exceeding the allowable speed of the transmission, and a speed capable of preventing the number of rotations of the motor from exceeding the allowable speed of the transmission when shifting from the third to the first speed.

In addition, referring to FIG. 5, if the transmission was able to implement only the first stage, the motor is relatively efficient by lowering the number of rotations of the motor by using the 2nd or 3rd stage in the driving condition that should have been driven at an excessively high motor rotational speed. It can be driven in an excellent area, and through this, it is possible to improve the fuel consumption of the vehicle and increase the mileage of the electric vehicle, and it can be seen that the motor rotational speed is relatively low, so that excellent noise and vibration characteristics of the vehicle can be secured. .

On the other hand, when shifting is performed in the shifting module SM by the driver's operation of the shift lever LV, the controller CLR releases the previous gear, engages the target gear, and then the main clutch CL It is configured to control the torque of the motor (M) to maintain the target speed of the motor (M) while gradually coupling through the slip control.

That is, as illustrated in FIG. 6, when shifting from 1st gear to 2nd gear, for example, the controller CLR controls the clutch actuator CA to release the main clutch CL, and the previous gear, the 1st gear After releasing, the second gear is engaged, and then the clutch actuator (CA) is controlled to fasten the main clutch (CL).At this time, the main clutch (CL) is slip-controlled to prevent the inertia of the drive system when shifting. The motor torque fluctuations due to the acceleration change are smoothly coupled so that the output torque of the vehicle is not affected, and at the same time, the motor (M) performs torque control to form and maintain the input shaft speed at the second stage of the target speed. To do it.

In addition, as illustrated in FIG. 7, in an embodiment of the method of controlling the transmission system for an electric vehicle of the present invention, when the controller CLR detects a risk of a sudden change in rotation of the motor M due to a driver's misoperation (S10 ), to release the main clutch CL with the clutch actuator CA (S20).

That is, in the state in which the shift module SM has a 2nd or 3rd gear, when a first shift is performed during high-speed driving (for example, 150Kph or more), or when a reverse shift is performed during forward high-speed driving, the rotation speed of the motor rapidly increases and the vehicle suddenly stops. Because a danger occurs, when the controller CLR detects this situation, the clutch actuator CA immediately releases the main clutch CL, thereby causing the motor M and the drive system to It is to prevent damage and deterioration of durability, as well as to improve the safety of the vehicle.

Although the present invention has been illustrated and described with reference to specific embodiments, it is understood in the art that the present invention can be variously improved and changed within the scope of the technical spirit of the present invention provided by the following claims. It will be obvious to a person of ordinary knowledge.

M; motor
CL; Main clutch
SM; Shifting module
IN; Input shaft
OUT; Output shaft
CLR; controller
TM; Transmission
W; Drive wheel
S1; First synchronizing device
S2; 2nd synchronization device
CA; Clutch actuator
SA1; 1st solenoid actuator
SA2; 2nd solenoid actuator

Claims (10)

An input shaft connected to the motor through the main clutch;
An output shaft disposed parallel to the input shaft;
A shift module installed between the input shaft and the output shaft to implement shifting between a plurality of shift stages in a synchronous mesh manner;
A clutch actuator installed to drive the main clutch;
An operating force transmission mechanism provided to transmit the shifting operating force of a driver to the shifting module in a mechanical linear displacement;
A controller provided to drive the clutch actuator according to the driver's shift operation;
Electric vehicle transmission system, characterized in that configured to include. The method according to claim 1,
The shifting module is
A first-stage driving gear and a first-stage driven gear having the largest transmission ratio meshed with each other;
A three-speed drive gear and a three-speed driven gear meshed with each other with the smallest transmission ratio;
A two-stage driving gear and a two-stage driven gear engaged with each other to have a transmission ratio between the first and third stages;
A first synchronization device installed to implement a first stage;
A second synchronization device installed to selectively implement the second and third stages;
Electric vehicle transmission system, characterized in that configured to include. The method according to claim 2,
The operation force transmission mechanism
A control finger installed to be movable in the selecting direction and the shifting direction by the driver's shift lever operation force;
A first shift rail installed to transmit an operating force from the control finger to the first synchronous device;
A second shift rail installed to transmit an operating force from the control finger to the second synchronous device;
A first lug and a second lug installed to transmit an operating force of the control finger in a shifting direction to the first and second shift rails, respectively;
Electric vehicle transmission system, characterized in that configured to include. The method of claim 3,
The control finger, the first lug, and the second lug are configured to realize a parking state of the vehicle by simultaneously moving the first shift rail and the second shift rail in a shifting direction.
Electric vehicle transmission system, characterized in that. The method of claim 4,
The control finger moves together in a state in which the first finger for pushing the first lug in the shifting direction and the second finger for pushing the second lug in the shifting direction are spaced apart wider than the thickness of the first finger in the selecting direction Configured to be;
The second lugs are aligned adjacent to the first lug in the selecting direction in a neutral state, and are formed thicker than the thickness of the first lug in the selecting direction, so that the first finger moves the first lug in the shifting direction. When pushing, the second finger is configured to push the second lug together in the shifting direction
Electric vehicle transmission system, characterized in that. The method of claim 3,
A first solenoid actuator provided to limit transmission of an operating force for implementing the first stage to the first synchronous device;
A second solenoid actuator provided to limit transmission of the operating force for implementing the second stage to the second synchronous device;
Including more,
The controller controls the first solenoid actuator according to a predetermined first vehicle speed condition to limit the shift from second to first stage, and controls the second solenoid actuator according to a predetermined second vehicle speed condition to control the third stage. To limit the shift from the third gear to the second gear, and to limit the shift from the third gear to the first gear by controlling the first solenoid actuator according to a predetermined third vehicle speed condition.
Electric vehicle transmission system, characterized in that. The method according to claim 1,
When the shifting module is shifted, the controller releases the previous gear, engages the target gear, and then gradually engages the main clutch through slip control, and controls the torque of the motor to maintain the target speed of the motor. Configured to
Electric vehicle transmission system, characterized in that. The method according to claim 1,
The controller is configured to release the main clutch with the clutch actuator when detecting a risk of sudden change in motor rotation due to a driver's misoperation
Electric vehicle transmission system, characterized in that. The method according to any one of claims 1 to 6,
When shifting the shifting module, controlling the torque of the motor to maintain the target speed of the motor while releasing the previous gear, engaging the target gear, and gradually engaging the main clutch by slip control
Electric vehicle transmission system control method, characterized in that. The method according to any one of claims 1 to 6,
Immediately releasing the main clutch with the clutch actuator when there is a risk of sudden change in motor rotation due to a driver's misoperation
Electric vehicle transmission system control method, characterized in that.

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