KR101135185B1 - Transmission for Electric Vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric vehicle transmission, and more particularly, it relates to a transmission for an electric vehicle in which an appropriate gear ratio is automatically formed in accordance with a vehicle speed, It is possible to provide a more energy-efficient vehicle running state, and the automatic shifting operation is performed by the control unit. Therefore, the operation by the user is unnecessary, so that a safer vehicle running performance can be provided. The present invention provides an automatic transmission for an electric vehicle, which automatically forms a gear ratio and determines a speed holding time of the vehicle, thereby determining whether or not the gear is to be shifted, thereby preventing frequent shifting and providing a more stable running performance.

Electric vehicle, transmission, two-speed, drive motor

Description

[0001] Transmission for Electric Vehicle [0002]

The present invention relates to an electric vehicle transmission. More specifically, a speed change ratio of an appropriate state is automatically formed in accordance with the vehicle speed, so that a speed control function for a drive motor required in all the speed sections is relaxed, thereby reducing the load on the drive motor, Since the automatic shifting operation is performed by the control unit, the operation by the user is unnecessary, so that it is possible to provide a safer vehicle running performance, automatically form a gear ratio in an appropriate state in accordance with the vehicle speed The present invention relates to a transmission for an electric vehicle that determines a speed holding time of a vehicle and determines whether or not the vehicle is to be shifted, thereby preventing a frequent shift and providing a more stable running performance.

Recently, global environmental problems have become a global concern, and environmental regulations have been strengthened especially in developed countries. Especially, exhaust gas regulations related to automobiles and regulations on fuel efficiency have been expanding.

Recently, the development trend of automobiles has been studied in order to develop vehicles with less pollution in place of vehicles using gasoline heavy oil as the main fuel, which is seriously affecting air pollution. There is a growing interest in electric vehicles with low noise and no emissions at all.

Electric vehicles use lead-acid batteries, which are secondary batteries, as driving power sources. Instead of conventional gasoline or diesel engines, they drive the drive motor with high voltage and high current output from the lead-acid battery and transmit the power generated by the drive motor to power transmission To the drive wheel through the device to rotate the drive wheel.

An electric vehicle operating in this manner has no explosion sound like an internal combustion engine and has no pollution such as air pollution. However, since the energy stored in the capacitor is limited and its operation principle differs from that of the internal combustion engine, Its structure must be changed in such a way as to change or additionally delete the transmission or the separate power transmission means.

Particularly, since the driving motor, which is the power source of the electric vehicle, is rotationally driven through the electric energy of the capacitor, the rotational force and the rotational speed of the driving motor can be directly controlled through the vehicle control unit and can be configured to change the vehicle speed accordingly. That is, unlike an internal combustion engine vehicle, an electric vehicle can be easily controlled with respect to a drive motor, so that the vehicle speed can be smoothly changed by controlling the drive motor even without a separate transmission.

However, if the speed of the vehicle is changed through the control of the driving motor, the load on the driving motor is increased, so that the power consumption is increased. As a result, the driving distance through one charging is shortened. And the configuration of the drive motor becomes complicated. Therefore, although a transmission suitable for a drive motor system is required for an electric vehicle in terms of energy efficiency, the research and development of a transmission for an electric vehicle is still insufficient to date.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior arts, and it is an object of the present invention to reduce the speed control function for a driving motor required in all speed sections by automatically forming a speed change ratio in an appropriate state according to the vehicle speed So that the load of the driving motor can be reduced to thereby provide a more energy-efficient vehicle running state, and the automatic shifting operation is performed by the control unit, so that operation by the user is unnecessary, thereby providing safer vehicle driving performance And an electric motor for driving the electric motor.

It is another object of the present invention to provide an automatic transmission that automatically forms a gear ratio in an appropriate state according to a vehicle speed and determines a speed holding time of the vehicle and determines whether or not to perform a shift according to the vehicle speed to thereby prevent frequent shifting, And it is an object of the present invention to provide a transmission for an electric vehicle capable of improving the durability of a vehicle component associated with the transmission power transmitting device.

The present invention relates to an electric vehicle transmission for changing the power generated by a drive motor and transmitting the same to a drive wheel, wherein first and second input gears having different gear ratios are combined and driven by the drive motor Input shaft; A clutch for connecting or disconnecting the drive motor and the input shaft so that the power of the drive motor is selectively transmitted to the input shaft; A counter shaft to which the first and second counter gears, which are always engaged with the first and second input gears, are engaged in a freely rotating state; The counter shaft linearly moves on the counter shaft in the axial direction so as to receive the power of the input shaft through the first counter gear or the second counter gear at a low speed stage or a high speed stage, Combining synchronizer; A clutch drive unit for operating the clutch; A synchronizer drive unit for operating the synchronizer to move linearly; And a control unit for controlling operations of the clutch drive unit and the synchronizer drive unit such that the power transmission state from the input shaft to the counter shaft is changed to a low speed or a high speed in two stages in accordance with the vehicle speed, And the combined output shaft is rotationally driven by receiving power from the counter shaft.

At this time, the clutch drive unit includes a release fork that presses the clutch so that power transmission between the drive motor and the input shaft is interrupted; An opera cylinder for transmitting a pressing force to the release fork by hydraulic pressure; And a clutch motor operated by the control unit to provide hydraulic pressure to the opera cylinder.

The clutch drive unit may further include a vacuum booster for generating vacuum pressure inside the clutch cylinder so as to multiply the oil pressure delivered to the operable cylinder by the clutch motor.

The electric vehicle transmission may further include a power cutoff sensor for sensing whether the power cutoff between the drive motor and the input shaft is generated by the operation of the clutch and applying the cutoff power to the control unit.

The synchronizer drive unit may further include: a shift fork coupled with the synchronizer; And a select motor operated by the control unit to linearly move the shift fork in the axial direction of the counter shaft.

The electric vehicle transmission may further include a position sensor for sensing a shift position of the shift fork and applying a position signal to the shift fork to the control unit.

The control unit controls the clutch drive unit and the synchronizer drive unit so that the power transmission state to the counter shaft is shifted to the high-speed end when the vehicle speed is equal to or higher than the first speed, And controls the operation of the clutch drive unit and the synchronizer drive unit such that the power transmission state to the counter shaft is shifted to the low speed stage, and the first speed may be set to a speed higher than the second speed.

The control unit may control the clutch drive unit and the synchronizer drive unit such that the power transmission state to the counter shaft is changed to the high-speed end when the vehicle speed is maintained at the first speed or more for a first set time or longer have.

In addition, when the vehicle speed is accelerated from the first speed to a third speed that is higher than the first speed within the first set time, the control unit changes the power transmission state to the counter shaft to the high- So that the clutch drive unit and the synchronizer drive unit can be controlled in operation.

The control unit may control the clutch drive unit and the synchronizer drive unit such that the power transmission state to the counter shaft is changed to the low speed position when the vehicle speed is maintained for a second set time in a state where the vehicle speed is less than the first speed, The operation of the unit can be controlled.

In addition, an input shaft speed sensor for measuring the rotational speed of the input shaft and applying the input shaft speed sensor to the control unit is mounted, and the control unit controls the clutch drive unit such that the input shaft and the drive motor are connected, The rotational speed of the driving motor can be controlled in accordance with the rotational speed of the driving motor.

According to the present invention, it is possible to automatically reduce the speed control function for the drive motor required in all the speed sections by automatically forming the gear ratio in an appropriate state in accordance with the vehicle speed, thereby reducing the load of the drive motor, It is possible to provide an efficient vehicle running state and an automatic shifting operation is performed by the control unit. Therefore, operation by the user is unnecessary, thereby providing a safer vehicle running performance.

In addition, it is possible to automatically form a gear ratio in an appropriate state according to the vehicle speed, determine a speed holding time of the vehicle, and determine whether or not the gear is to be shifted accordingly, thereby preventing frequent shifting to provide a more stable running performance, The durability of the vehicle parts related to the present invention can be improved.

In addition, an input shaft speed sensor capable of measuring the rotational speed of the input shaft is provided to control the speed of the drive motor so as to correspond to the rotational speed of the input shaft when the input shaft and the drive motor are connected, thereby minimizing a shift shock There is an effect that can be.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is an exploded perspective view schematically showing a structure of a transmission for an electric vehicle according to an embodiment of the present invention. FIG. 2 is a schematic view showing the operation state of the transmission for an electric vehicle according to an embodiment of the present invention. 3 is a block diagram showing a control operation function for the electric vehicle transmission according to the embodiment of the present invention.

An electric vehicle transmission according to an embodiment of the present invention is an apparatus for transmitting power generated by a drive motor 100 to a drive wheel (not shown) of a vehicle through a plurality of gears in a changed state, Speed shifting function of the high-speed stage and the low-speed stage so as to be suitable for the shifting function, and is configured to automatically operate according to the vehicle speed through the vehicle control unit 900 instead of operating through the operation by the user.

The transmission for electric vehicles includes an input shaft 400 rotationally driven by a drive motor 100, a clutch 200 connecting or disconnecting the drive motor 100 and the input shaft 400, A synchronizer 600 selectively applying the power transmission state of the counter shaft 500 to the high speed stage and the low speed stage and the clutch 200 and the synchronizer 600 respectively And a control unit 900 for controlling the operation of the clutch drive unit 300 and the synchronizer drive unit 700. The control unit 900 controls the clutch drive unit 300 and the synchronizer drive unit 700, At this time, the output shaft 800 to which the driving wheel of the vehicle is coupled is configured to be rotationally driven by receiving the power of the counter shaft 500.

The input shaft 400 is connected to and disconnected from the driving motor 100 through the clutch 200 so that the power of the driving motor 100 is selectively transmitted according to the operation of the clutch 200. That is, in the normal running mode, the input shaft 400 and the driving motor 100 are connected by the clutch 200 so that the rotational force of the driving motor 100 is transmitted to the input shaft 400. In the shifting mode, The rotational force of the driving motor 100 is not transmitted to the input shaft 400 due to the connection / disconnection of the driving motor 100 from the driving motor 100. A first input gear 410 and a second input gear 420 having different gear ratios are coupled to the input shaft 400 and integrally rotated with the input shaft 400. The first input gear 410 is coupled to the input shaft 400 at a low speed And the diameter of the second input gear 420 is smaller than that of the second input gear 420.

The clutch 200 selectively connects and disconnects the motor shaft (not shown) and the input shaft 400 of the drive motor 100 and includes a clutch disc (not shown), a clutch pressure plate (not shown) And is configured to operate by a separate external force. Since this clutch 200 corresponds to a known technique, a detailed description will be omitted.

The counter shaft 500 is disposed in parallel with the input shaft 400 and is coupled to the first counter gear 510 and the second counter gear 520 so as to receive the rotational force of the input shaft 400. The first counter gear 510 is engaged with the first input gear 410 and the second counter gear 520 is configured to be engaged with the second input gear 420. This gear engagement is always engaged . At this time, the first counter gear 510 is engaged with the first input gear 410, and the diameter of the first counter gear 510 is larger than that of the second counter gear 520 so as to perform a low-speed shift. That is, a low-speed shift function is performed through the first input gear 410 having a relatively small diameter and the first counter gear 510 having a relatively large diameter, and the second input gear 420 having a relatively large diameter is operated. And the second counter gear 520 having a relatively small diameter. However, the diameters of these gears may be varied within the limits of the two-speed range of low speed and high speed depending on the needs of the user.

The first and second counter gears 510 and 520 are coupled to the counter shaft 500 such that the first and second counter gears 510 and 520 are freely rotatable. A synchronizer 600 is mounted on the shaft 500. The synchronizer 600 is coupled with the counter shaft 500 by being splined to be integrally rotated and movably coupled in the axial direction. The synchronizer 600 is disposed between the first and second counter gears 510 and 520, 1 and the second counter gears 510, 520, respectively. That is, when the synchronizer 600 moves toward the first counter gear 510 and engages with the first counter gear 510, the first counter gear 510 rotates integrally with the counter shaft 500, The second counter gear 520 rotates integrally with the counter shaft 500 when the first counter gear 600 moves toward the second counter gear 520 and is coupled with the second counter gear 520. [ At this time, the synchronizer 600 synchronizes the rotational speeds of the counter gears 510 and 520 with the counter shaft 500, and then operates in a manner of being engaged with the counter gears 510 and 520. Thus, And is configured to minimize impact. Since the synchronizer 600 corresponds to a known technology widely used in a transmission of a conventional internal combustion engine vehicle, a detailed description thereof will be omitted.

When the synchronizer 600 linearly moves and selectively engages with the first and second counter gears 510 and 520 as described above, the counter shaft 500 is connected to the first counter gear 510 coupled to the synchronizer 600, 2 counter gear 520 and receives the power of the input shaft 400 at a low speed or a high speed gear ratio. That is, when the synchronizer 600 is coupled to the first counter gear 510, the rotational force of the input shaft 400 is transmitted through the first input gear 410 and the first counter gear 510, When the synchronizer 600 is coupled to the second counter gear 520, the rotational force of the input shaft 400 is transmitted to the second input gear 420 and the second counter gear 520 through the high- To the counter shaft (500).

A separate driving gear 530 is coupled to the counter shaft 500 so as to rotate integrally with the counter shaft 500. The driving gear 530 includes an output gear 810 . The output gear 810 is coupled to the output shaft 800 and the driving wheel (not shown) coupled to the output shaft 800 is rotationally driven as the output shaft 800 is rotationally driven by the rotation of the output gear 810. That is, the power of the drive motor 100 is transmitted to the input shaft 400 and is transmitted through the first input gear 410 and the first counter gear 510 or through the second input gear 420 and the second counter gear 520 to the counter shaft 500 at a low speed or high speed gear ratio and the rotational force of the counter shaft 500 is transmitted to the output shaft 800 and the drive wheel through the drive gear 530 and the output gear 810 . Through the power transmission process, the driving wheel is rotated and driven.

The clutch drive unit 300 functions to operate the clutch 200 to connect and disconnect the power transmission between the drive motor 100 and the input shaft 400. The synchronizer drive unit 700 includes a synchronizer 600, So that the first and second counter gears 510 and 520 are selectively coupled to each other.

The control unit 900 controls the operation of the clutch drive unit 300 and the synchronizer drive unit 700 and controls the power transmission from the input shaft 400 to the counter shaft 500 to the low speed or high speed So that the vehicle is shifted in two-step speed ratio.

According to such a structure, the transmission for an electric vehicle according to an embodiment of the present invention forms a proper gear ratio according to the vehicle speed, thereby alleviating the speed control function for the driving motor 100 required in all the speed sections So that the load of the drive motor 100 can be reduced, thereby providing a more energy-efficient vehicle running state. Further, since the electric vehicle transmission is automatically shifted by the control unit 900, no operation by the user is required, and a safer running performance of the vehicle can be provided.

On the other hand, the clutch drive unit 300 for operating the clutch 200 includes a release fork 310 connected to the clutch 200 to pressurize and depressurize the clutch 200 according to one embodiment of the present invention, An opera cylinder 320 for transmitting a pressing force to the operative cylinder 310 and a clutch motor 340 for providing hydraulic pressure to the opera cylinder 320. [

The release fork 310 is configured to be hinged to a separate hinge shaft 311 so as to rotate in a leaning manner to pressurize or release the clutch 200. When the clutch 200 is pressed, And the input shaft 400 are interrupted. The opera cylinder 320 is coupled to an end of the release fork 310 and is configured to transmit a pressing force to the release fork 310 by hydraulic pressure so that the release fork 310 rotates about the hinge shaft 311. This is a configuration widely used in a general clutch device. In a general clutch device, hydraulic pressure is supplied to an opera cylinder by the user's pressure, and the hydraulic pressurizes the release fork and presses the clutch. However, the clutch drive unit 300 according to the embodiment of the present invention is provided with a separate clutch motor 340 as an apparatus for supplying the hydraulic pressure to the opera cylinder 320, and the clutch motor 340 has a control unit 900, respectively. At this time, the clutch motor 340 and the opera cylinder 320 are interconnected to provide hydraulic pressure through the hydraulic pipe 350.

Therefore, in the transmission of the electric vehicle according to the embodiment of the present invention, the clutch motor 340 is controlled by the control unit 900 in the course of shifting according to the vehicle speed and provides the hydraulic pressure to the opera cylinder 320, The release fork 310 presses the clutch 200 so that the input shaft 400 is powered off from the drive motor 100.

At this time, the clutch drive unit 300 may further include a vacuum booster 330 for generating vacuum pressure inside the clutch cylinder 340 so as to multiply the hydraulic pressure transmitted to the opera- tor cylinder 320 by the clutch motor 340 . Therefore, even if the capacity of the clutch motor 340 becomes relatively small, the hydraulic pressure supplied to the opera cylinder 320 is doubled by the vacuum booster 330, so that the smooth hydraulic pressure supply is possible, 340 can be reduced and the overall energy efficiency of the vehicle can be improved.

The synchronizer drive unit 700 that operates to move the synchronizer 600 linearly includes a shift fork 710 coupled to the synchronizer 600 and a shift fork 710 coupled to the shift fork 710 in the axial direction And a select motor 730 that is operated by the control unit 900 to linearly move the motor to the target position. At this time, the shift fork 710 is coupled to a separate shift rod 720, and the select motor 730 can be configured in such a manner that the shift rod 720 linearly moves in the longitudinal direction.

Accordingly, in the transmission of the electric vehicle according to the embodiment of the present invention, the input shaft 400 is disengaged from the driving motor 100 by the clutch driving unit 300 in the process of shifting according to the vehicle speed In this state, the synchronizer 600 operates through the synchronizer drive unit 700, and the shift function is performed at a high speed or low speed. All of these shift functions are configured to be performed automatically according to the vehicle speed through the control unit 900. [

2 (a), in the first traveling state of the vehicle, the shift from the input shaft 400 to the counter shaft (not shown) is performed in accordance with the shifting process of the electric vehicle transmission according to the embodiment of the present invention. 500 is configured such that the synchronizer 600 is coupled to the first counter gear 510 to maintain the speed ratio of the low speed stage through the first input gear 410 and the first counter gear 510 . The rotational force of the input shaft 400 that is transmitted from the drive motor 100 through the clutch 200 is transmitted to the counter shaft 500 through the first input gear 410 and the first counter gear 510 at a low speed And the rotational force of the counter shaft 500 is transmitted to the output shaft 800 through the driving gear 530 and the output gear 810. [

When the vehicle speed changes to a specific speed while the vehicle is traveling in this state, the clutch 200 is operated by the clutch drive unit 300 as shown in FIG. 2 (b) And the drive motor 100 are interrupted. The synchronizer drive unit 700 disengages the synchronizer 600 from the first counter gear 510 in a state where the power of the drive motor 100 is cut off by the input shaft 400. [ Therefore, in this case, the power of the drive motor 100 is not transmitted to both the input shaft 400 and the counter shaft 500, so that the power of the drive motor 100 is not transmitted to the output shaft 800, , Which corresponds to a transient state that occurs during the shifting process.

As shown in FIG. 2 (b), the shifting process of the shift device is shifted to the high-speed stage as shown in FIG. 2 (c) through a neutral state in the daytime. The synchronizer 600 is coupled to the second counter gear 520 by the synchronizer drive unit 700 so that the rotational force of the input shaft 400 is transmitted through the second input gear 420 and the second counter gear 520 And is transmitted to the counter shaft 500 at a high speed gear ratio. After the operation of the synchronizer 600 is completed, the clutch drive unit 300 operates and connects the input shaft 400 and the drive motor 100 to transmit the power of the drive motor 100 to the input shaft 400 . The rotational force of the input shaft 400 that is transmitted from the drive motor 100 through the clutch 200 is transmitted to the counter shaft 500 through the second input gear 420 and the second counter gear 520 And the rotational force of the counter shaft 500 is transmitted to the output shaft 800 through the driving gear 530 and the output gear 810. [

As described above, the shifting process described above is automatically performed by the control unit 900 and automatically performed by the clutch drive unit 300 and the synchronizer drive unit 700. As described above, in the electric vehicle 100 according to the embodiment of the present invention, The power transmission apparatus may further include a separate power shut-off detection sensor 920 that can accurately detect the operating state of the clutch 200. [ The power cutoff detection sensor 920 is configured to detect whether or not power is interrupted between the drive motor 100 and the input shaft 400 generated by the operation of the clutch 200. This is because the hydraulic pressure Or may be configured in such a manner as to measure the pressing position of the release fork 310, or the like.

The power cutoff detection sensor 920 is configured to detect whether the drive motor 100 and the input shaft 400 are powered off, and to apply the sensed signal to the controller 900. Therefore, it is preferable that the controller 900 controls the synchronizer driving unit 700 to operate only when the power is cut off according to the signal of the power cutoff detection sensor 920.

1 and 2, the transmission for an electric vehicle according to an embodiment of the present invention senses the shift position of the shift fork 710 and outputs a position signal for the shift fork 710 to the controller 900 And a position sensor P1 or P2 for applying an electric current to the position sensors P1 and P2. The speed ratio in the current running state can be accurately grasped by the position sensors P1 and P2, so that a more accurate and safe shifting operation can be performed.

The position sensors P1 and P2 are composed of two low speed single position sensors P1 and two high speed single position sensors P2 and can be configured as optical sensors. In this case, the position sensors P1 and P2 correspond to the position sensors P1 and P2, respectively. The detector block 710 may be mounted separately. For example, as shown in Figs. 1 and 2, the position sensors P1 and P2 are fixedly mounted at specific positions and the detector block 710 is mounted to the shift rod 720 to move with the shift fork 710 So that the respective shift states can be detected by the position sensors P1 and P2 and the detector block 710 as shown in Figs. 2 (a) to 2 (c). That is, in the low-speed shift state, the low-speed single-stage position sensor P1 and the detector block 710 are arranged in line so that the high-speed single-stage position sensor P2 and the detector block 710 coincide with each other And in a neutral state, the position sensors P1 and P2 and the detector block 710 are arranged so as not to coincide with each other.

In this case, the position sensors P1 and P2 may be configured in the form of a simple limit switch as well as an optical sensor so that the limit switch is interfered by the detector block 710 and operated at the corresponding position. In addition, And may be configured with a variety of sensors and operation methods capable of sensing the position of the sensor.

The transmission for an electric vehicle according to an embodiment of the present invention may further include an input shaft speed sensor 930 for measuring a rotational speed of the input shaft 400 and applying a rotational speed signal to the control unit 900, The control unit 900 controls the rotational speed of the input shaft 400 by the input shaft speed sensor 930 so as to prevent the shift shock from occurring in the process of connecting the input shaft 400 and the drive motor 100 through the clutch drive unit 300 It is preferable that the rotation speed of the drive motor 100 is controlled in accordance with the control signal.

The input shaft 400 is disengaged from the drive motor 100 by the clutch drive unit 300 during the shifting process and then transmitted to the synchronizer 600 through the synchronizer drive unit 700. [ ) And the counter gear is changed to the low-speed stage or the high-speed stage. When the operation of the synchronizer drive unit 700 is completed, the clutch drive unit 300 again connects the input shaft 400 to the drive motor 100. At this time, the rotation of the drive motor 100 and the input shaft 400 If the speeds are different, an impact will occur in the process of connecting them. Therefore, in the transmission according to the embodiment of the present invention, the rotational speed of the input shaft 400 is measured by the input shaft speed sensor 930, and the rotational speed of the driving motor 100 Is rotated through the control unit 900 so as to rotate. In this process, the rotational speed of the input shaft 400 and the driving motor 100 is equalized in the process of connecting the input shaft 400 to the driving motor 100, thereby minimizing the shift shock that occurs during shifting.

As shown in FIG. 3, the transmission for electric vehicles according to an embodiment of the present invention configured as described above is adapted to perform two-speed shifting to a low-speed or high-speed end according to the vehicle speed measured by a separate vehicle speed sensor 910 Respectively. At this time, the vehicle speed sensor 910 is generally composed of a speed sensor mounted on the vehicle.

3, the control unit 900 includes a vehicle speed sensor 910, a power cutoff detection sensor 920, position sensors P1 and P2, and an input shaft speed sensor 930 And controls the clutch drive unit 300, the synchronizer drive unit 700, and the drive motor 100 in the manner described above. Since each sensor and components operate as described above, detailed description thereof will be omitted so as not to duplicate.

4 is a flowchart showing a shift control method according to a vehicle speed of an electric vehicle transmission according to an embodiment of the present invention.

The transmission 900 for an electric vehicle according to an embodiment of the present invention performs a function of automatically shifting to a low speed and a high speed according to the speed of the vehicle as described above. And controls the clutch drive unit 300 and the synchronizer drive unit 700 so that the power transmission state to the counter shaft 500 is shifted to the high-speed end when the vehicle speed is equal to or greater than the first speed, The clutch drive unit 300 and the synchronizer drive unit 700 are controlled such that the power transmission state to the counter shaft 500 is shifted to the low speed end. At this time, the first speed should be set to a higher speed than the second speed, preferably the first speed may be set to 80 km / h, and the second speed may be set to 60 km / h.

At this time, the controller 900 may control the power transmission state to be shifted to the high-speed stage immediately when the vehicle speed becomes equal to or higher than the first speed. However, according to the embodiment of the present invention, It is preferable to control the operation of the clutch drive unit 300 and the synchronizer drive unit 700 so that the power transmission state to the counter shaft 500 is shifted to the high-speed end when it is maintained for one set time or more. This makes it possible to prevent frequent shifting when the vehicle speed is repeatedly accelerated and decelerated while the vehicle speed is close to the first speed. At this time, the first set time can be variously set according to the driving conditions and the user's needs, for example, 3 seconds, 5 seconds, or the like.

In addition, when the vehicle speed is accelerated from the first speed to the third speed or more within a first set time, which is higher than the first speed, the control unit 900 determines that the power transmission state to the counter shaft 500 is the high- The operation of the clutch drive unit 300 and the synchronizer drive unit 700 can be controlled. At this time, the third speed can be variously set, but if the first speed is set to 80 km / h as described above, it is preferable that the third speed is set to 90 km / h.

On the other hand, when the vehicle speed is maintained for the second set time set by the user in a state where the vehicle speed exceeds the second speed and does not reach the first speed, the power transmission state to the counter shaft 500 becomes low speed The clutch drive unit 300 and the synchronizer drive unit 700 can be controlled in operation. At this time, the second set time may be variously set to 3 seconds, 5 seconds, 7 seconds, and the like, and the same or different time as the first set time can be selected.

4, the shift state of the vehicle is formed at a low speed in the initial state S1 of the vehicle. When the vehicle starts to travel, the vehicle speed sensor (S2), and the speed maintenance time at which the measured vehicle speed condition is maintained is measured (S3). The controller 900 determines whether the vehicle speed is equal to or greater than the first speed (S4). If it is determined that the vehicle speed is equal to or greater than the first speed, it is determined whether the speed maintenance time is equal to or greater than the first predetermined time (S5). The control unit 900 activates the clutch drive unit 300 and the synchronizer drive unit 700 so that the vehicle speed is higher than the first speed Speed shifting ratio by engagement of the input gear 420 and the second counter gear 520 (S7). If the vehicle speed is equal to or higher than the first speed and the speed holding time is within the first predetermined time, it is determined whether the vehicle speed is equal to or higher than the third speed (S6). At this time, if the vehicle speed is equal to or higher than the third speed, the control unit 900 controls the speed change so as to form a high speed ratio (S7). However, when the vehicle speed is equal to or lower than the third speed, the vehicle speed and the speed maintenance time are repeatedly determined to determine the vehicle speed again (S2). The vehicle speed and the speed maintenance time are again determined, As shown in FIG. Even if the shift control is performed so as to form a high speed ratio, this cycle determination should be continued.

If the vehicle speed measured by the vehicle speed sensor 910 is less than the first speed, the controller 900 determines whether the vehicle speed is equal to or less than the second speed (S8). The control unit 900 operates the clutch drive unit 300 and the synchronizer drive unit 700 to drive the first input gear 410 and the first counter gear 510 at a low speed So that a speed change ratio is formed (S10). If the vehicle speed exceeds the second speed, the control unit 900 determines whether the speed maintenance time is equal to or greater than the second predetermined time (S9). If the vehicle speed is equal to or greater than the second predetermined time, (Step S2) of judging the vehicle speed again when the vehicle speed is less than the second set time, and continues to determine the vehicle speed and the speed holding time. In the case where the shift is controlled so as to form the low speed ratio, similarly, such a cycle determination should be continued.

The first speed is set to 80 km / h, the second speed is set to 60 km / h, the third speed is set to 90 km / h, the first set time is set to 3 seconds, If the vehicle speed is 80 km / h and the vehicle is accelerated, the speed is set to 80 km / h for 3 seconds Or when the vehicle is further accelerated at a speed of 90 km / h within 3 seconds, the transmission of the vehicle is shifted to the high-speed end. Then, when the vehicle speed is decelerated and the vehicle speed is less than 60 km / h, the vehicle transmission is again shifted to the low speed.

If the vehicle speed is higher than 60 km / h and less than 80 km / h, the vehicle speed change device does not operate the speed change and maintains the current speed ratio. That is, if the current shift state is a low-speed state, the low-speed state is maintained. If the current state is a high-speed state, the high- However, if such a vehicle speed is maintained for 5 seconds or more, the vehicle transmission shifts the vehicle shift state to a low speed position. At this time, if the current shift state is a low speed state, the result is maintained as it is at low speed.

Accordingly, the transmission for an electric vehicle according to the embodiment of the present invention automatically shifts within such a speed range to relax the speed control function for the driving motor 100, And the energy efficiency is improved. Further, by determining whether or not the vehicle is to be shifted according to the vehicle speed holding time, frequent shifting can be prevented to provide a more stable running performance and durability of the vehicle parts related to the transmission.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

1 is an exploded perspective view schematically showing a structure of a transmission for an electric vehicle according to an embodiment of the present invention,

2 is an operational state diagram conceptually showing an operating state of the transmission for an electric vehicle according to an embodiment of the present invention;

3 is a block diagram showing a control operation function for a transmission for an electric vehicle according to an embodiment of the present invention;

4 is a flowchart showing a shift control method according to a vehicle speed of an electric vehicle transmission according to an embodiment of the present invention.

Description of the Related Art

100: drive motor 200: clutch

300: clutch drive unit 400: input shaft

500: counter shaft 600: synchronizer

700: Synchronizer drive unit 800: Output shaft

900:

Claims (11)

delete A transmission for an electric automobile that changes power generated by a drive motor and transmits the generated power to a drive wheel, An input shaft coupled to first and second input gears having different gear ratios and rotationally driven by the drive motor; A clutch for connecting or disconnecting the drive motor and the input shaft so that the power of the drive motor is selectively transmitted to the input shaft; A counter shaft to which the first and second counter gears, which are always engaged with the first and second input gears, are engaged in a freely rotating state; The counter shaft linearly moves on the counter shaft in the axial direction so as to receive the power of the input shaft through the first counter gear or the second counter gear at a low speed stage or a high speed stage, Combining synchronizer; A clutch drive unit for operating the clutch; A synchronizer drive unit for operating the synchronizer to move linearly; And A control unit for controlling the operation of the clutch drive unit and the synchronizer drive unit so that the power transmission state from the input shaft to the counter shaft is changed to the low speed or the high speed in two- Wherein the output shaft to which the driving wheel is coupled is rotationally driven by receiving power from the counter shaft, The clutch drive unit A release fork that presses the clutch so that power transmission between the drive motor and the input shaft is blocked; An opera cylinder for transmitting a pressing force to the release fork by hydraulic pressure; And And a clutch motor actuated by said control to provide hydraulic pressure to said opera cylinder, Wherein the control unit controls the clutch drive unit and the synchronizer drive unit such that the power transmission state to the counter shaft is changed to the high-speed end when the vehicle speed is maintained at the first speed or more for a first predetermined time or longer, And controls the clutch drive unit and the synchronizer drive unit such that the power transmission state to the counter shaft is shifted to the low speed when the second speed is lower than the first speed, Speed operation of the clutch drive unit and the synchronizer drive unit so that the power transmission state to the counter shaft is changed to the low-speed end when the speed of the counter shaft is maintained for a second set time while the speed is less than the speed. 3. The method of claim 2, The clutch drive unit Further comprising a vacuum booster for forming a vacuum pressure inside the clutch cylinder so as to multiply the hydraulic pressure transmitted to the opera cylinder by the clutch motor. 3. The method of claim 2, Further comprising a power cut-off detection sensor for detecting whether the power is interrupted between the drive motor and the input shaft caused by the operation of the clutch and applying the sensed power to the control unit. 3. The method of claim 2, The synchronizer drive unit A shift fork coupled with the synchronizer; And A selector motor operated by the control unit for linearly moving the shift fork in the axial direction of the counter shaft, And an electric motor for driving the electric motor. 6. The method of claim 5, Further comprising a position sensor for detecting a shift position of the shift fork and applying a position signal to the shift fork to the control unit. delete delete 3. The method of claim 2, Wherein when the vehicle speed is accelerated from the first speed to a third speed that is higher than the first speed within the first set time, The clutch drive unit, and the synchronizer drive unit. delete 3. The method of claim 2, An input shaft speed sensor for measuring the rotational speed of the input shaft and applying the measured rotational speed to the control unit, Wherein the control unit controls the rotation speed of the drive motor in accordance with the rotation speed of the input shaft so that a shift shock is not generated in the process of coupling the input shaft and the drive motor by the clutch drive unit gearbox.

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