JPH04289701A - Regenerative braking system for electric motor coach - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative braking system for an electric vehicle.

0002

2. Description of the Related Art As is well known, an electric vehicle is equipped with an electric motor and runs by supplying power to the electric motor from a battery. In such an electric vehicle, regenerative braking is performed during braking, and the kinetic energy of the vehicle is recovered as electric power to charge the battery.

[0003] In general, regenerative braking devices used in such electric vehicles have switch elements connected in a bridge shape to form a battery charging circuit, as described in Japanese Unexamined Patent Publication No. 2-36701. A charging circuit is interposed between the electric motor and the battery. When the vehicle is braked, a control pulse signal is output to this battery charging circuit to turn on/off the switch element, and the battery is charged with the electric power generated in the electric motor by this battery charging circuit.

0004

[Problems to be Solved by the Invention] However, in the conventional regenerative braking device as described above, if the duty factor of the control pulse signal input to the charging circuit is constant, the braking force is exhibits an upwardly convex parabolic characteristic (see FIG. 9). For this reason, there is a problem in that the braking force becomes excessive at a rotational speed where this characteristic takes its maximum value, and this excessive braking force impairs the braking feeling. On the other hand, it is thought that the above-mentioned problem can be solved by selecting the duty factor of the control pulse signal so that the maximum braking force does not become excessive.
Since the braking force has a parabolic characteristic that is convex upward with respect to the rotational speed, the braking force in the high rotational speed region and the low rotational speed region becomes small, making it impossible to obtain sufficient braking force in the high rotational speed region. A problem arises.

The present invention has been made in view of the above problems, and provides a regenerative braking device for an electric vehicle that can obtain braking force with a characteristic that increases as the rotational speed of an electric motor increases.
The purpose is to improve the braking feeling and to obtain a large braking force when the electric motor rotates at high speed.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a driving wheel to a rotating shaft of an electric motor via a power transmission system, and provides a battery charging circuit between the electric motor and a battery. In a regenerative braking device for an electric vehicle that performs regenerative braking by turning on/off according to the duty factor of the control pulse signal input to the battery charging circuit, the battery charging circuit has a duty factor of the control pulse signal input to the battery charging circuit. is made small in a high rotational speed range according to the rotational speed of the rotating shaft of the electric motor, and the braking force is increased as the rotational speed of the rotating shaft increases within a range not exceeding a predetermined braking force.

[0007] The regenerative braking device of the present invention includes a first motor in the power transmission system that responds to the rotational speed of the rotating shaft of the electric motor.
The first clutch may be provided, and the power transmission system may be configured to be disconnected by the first clutch when the rotational speed of the rotating shaft of the electric motor is below a predetermined rotational speed. In addition, in the regenerative braking device of this aspect, a second clutch that responds to the rotational speed of the drive wheel is provided in the power transmission system in parallel with the first clutch, and the second clutch is connected to the rotation speed at which the first clutch operates. The power transmission system can be configured in such a manner that the power transmission system is connected in a speed range exceeding a rotational speed lower than the rotational speed.

Furthermore, the regenerative braking device of the present invention can be configured such that a continuously variable transmission is provided in the power transmission system, and regenerative braking is performed by the charging circuit while the continuously variable transmission is operated to shift to a high reduction ratio side. .

[0009]

[Operation] The regenerative braking device for an electric vehicle of the present invention has an upwardly convex parabolic characteristic in which the braking force has a rotational speed characteristic, and
Using the duty factor of the control pulse signal as a parameter, we focused on the fact that the braking force decreases as the duty factor decreases, and as the rotational speed of the electric motor increases, the duty factor of the control pulse signal is decreased to reduce the braking force to a predetermined braking force. The size should be increased as the number of electric motors increases within a range that does not exceed . Therefore, a good braking feeling can be obtained without the braking force becoming excessive, and a large braking force can be obtained even at high rotational speeds.

The regenerative braking device for an electric vehicle of the present invention further includes providing a first clutch in the power transmission system that responds to the rotational speed of the electric motor and connects in a region where the rotational speed of the electric motor exceeds a predetermined speed. Therefore, regenerative braking is always performed in a region where the rotational speed of the electric motor is high, and energy can be recovered effectively. By providing a second clutch that responds to the rotational speed of the drive wheel in parallel with the first clutch and configuring the second clutch to be connected at a lower rotational speed than the first clutch, the Energy can be recovered effectively.

Furthermore, in the regenerative braking device for an electric vehicle of the present invention, a continuously variable transmission is provided in the power transmission system, and regenerative braking is performed while the continuously variable transmission is operated to shift toward a higher reduction ratio. Therefore, even if the rotational speed of the drive wheels decreases, the speed of the electric motor is increased, and energy recovery efficiency can be increased.

0012

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show a regenerative braking device for an electric vehicle according to an embodiment of the present invention, in which FIG. 1 is a side view of an electric two-wheeled vehicle as an electric vehicle, FIG. 2 is a sectional view of a power unit, FIG. 3 is a circuit diagram, FIG. 4 is a flowchart showing the control processing.

In FIG. 1, reference numeral 11 denotes a vehicle body frame that is approximately U-shaped in side view, and the vehicle body frame 11 includes a front frame 11f, a center frame 11d, and a rear frame 1.
It has 1r. This body frame 11 includes a front cover 21f, a leg shield 21a, and a step floor 21b.
, a synthetic resin body 21 consisting of a rear cover 21c and an undercover 21d.

[0014] The vehicle body frame 11 includes a front frame 1.
A head tube 12 is fixed to the front part of 1f, and a front wheel 14 is connected to this head tube 12 via a front fork 13.
f is supported so as to be steerable by a steering handle 15. Although not shown in FIG. 1, an accelerator sensor 37 (see FIG. 3) consisting of a potentiometer or the like that detects the operating angle of the accelerator grip is attached to the steering handle 15.

A control box 16 is attached to the front of the head tube 12, and the front of the control box 16 is covered by a front cover 21f. A controller 49 consisting of an ECU or the like is housed inside the control box 16. This controller 4
9 will be described later.

Further, in the vehicle body frame 11, a battery box 22 is provided on a center frame 11d, and a power swing unit 50 is swingably supported at the rear of the center frame 11d by a pivot shaft (not shown). The power swing unit 50 is formed by assembling an electric motor 52 and the like to a case body 51, as will be described later, and rotatably supports a rear wheel (drive wheel) 14r at the rear end of the case body 51. Note that 99 is a cushion unit interposed between the rear part of the power swing unit 50 and the vehicle body frame 11.

The battery box 22 is mounted on a battery holder 23 fixed to the center frame 11d.
It is fastened with a band 24. A plurality of batteries 36 (see FIG. 3) are housed inside the battery box 22, and these batteries 36 are connected in parallel or in series to a drive circuit described later, a controller 49 described above, and the like. Although not clearly shown in the figure, the battery holder 23
is a plate-shaped member installed in the vehicle width direction at the lower part of the center frame 11d, and the above-mentioned step floor 21b is fixed onto the battery box 22 mounted on the battery holder 23 via a band 24. .

Further, in the vehicle body frame 11, the above-mentioned rear cover 21c is fixed to the rear frame 11r. The rear cover 21c has a substantially hollow cylindrical shape with an open top, and a sheet 26 is supported on the top so that the opening can be closed. The seat 26 has a hinge at the front and a rear cover 21c.
It closes the opening of the rear cover 21c when the seat is ready for sitting (see FIG. 1), and opens the opening of the rear cover 21c when it is tilted forward.

A trunk box 25 and a charging box 27 are housed in the rear cover 21c, diagonally above and in front of the rear wheel 14r. The trunk box 25 has an open top, and the top opening is covered with the above-mentioned sheet 26 so as to be openable and closable. This trunk box 25 has a size that can accommodate a helmet.

[0020] The charging box 27 has a substantially L-shape when viewed from the side with the front part protruding upward, and the front upper part is open. This charging box 27 houses a charger for charging from a commercial AC power source, etc. inside, and its front upper opening is covered by a lid 28 so as to be openable and closable. A charging circuit 97 is provided on one side of the lid 28, and the charging circuit 97 and the charger are connected to the battery 36 and the like. In addition, in FIG. 1, 88 is an intake duct arranged in the rear cover 21c, and one end of the intake duct 88 is connected to the cooling air inlet of the power swing unit 50.
The other end opens into the rear cover 21c.

As shown in FIG. 2, the power swing unit 50 includes a case body 51 whose front end is swingably supported by the vehicle body frame 11, an electric motor 52, and a continuously variable transmission 5.
3 and the final reduction mechanism 54 are integrally assembled. The case body 51 is formed by casting an aluminum alloy or the like, and has a recess 51a on the right side of the front and a recess 51b on the left side of the rear.

The case body 51 has a recess 51 on the front right side.
A motor chamber 31 has a motor case 60 fixed thereto and houses the electric motor 52, and a gear chamber 5 has a bearing member 57 fixed to the rear left recess 51b and houses the final reduction mechanism 54.
8 is defined, and a side cover 55 is fixed to the left side to define a transmission chamber 56 that accommodates a continuously variable transmission 53. The above-mentioned motor chamber 31 and transmission chamber 56 are connected to the case body 5.
1 through a through hole 34 formed near the bottom surface of the recess 51a, and the transmission chamber 56 is opened to the atmosphere from an exhaust port (not shown).

The motor case 60 has a bottomed cylindrical shape with an open end, and is fixed to the case body 51 with bolts 30 with the opening aligned with the opening of the recess 51a to define the motor chamber 31. A bearing 32 is provided at the bottom of the motor case 60, and a rotary shaft 61 is rotatably installed in the motor chamber 31 by the bearing 32 and a bearing 33 provided at the bottom of the recess 51a of the case body 51.

One end of the rotating shaft 61 passes through the bottom of the recess 51a and is connected to the continuously variable transmission 53 within the transmission chamber 56, and the other end passes through the bottom of the motor case 60. This rotating shaft 6
1, a cooling fan 59 is installed in the motor chamber 31 at a position close to the bottom of the recess 51a and facing the through hole 34.
A rotor 63 made of a magnet is fixed at the center of the motor case 60, and a rotation sensor 70 is attached to an end penetrating the bottom of the motor case 60. As is well known, rotor 6
3 is composed of a magnet and is located inside the stator.

The cooling fan 59 rotates together with the rotating shaft 61 and supplies cooling air from the above-mentioned intake duct 88 to the motor chamber 31.
The cooling air is introduced into the transmission chamber 56 through the ventilation hole 34. The rotation sensor 70 includes a magnet fixed to the rotating shaft 61 and a magnetically sensitive element such as an MR element attached to the bottom right side of the motor case 60, and this magnetically sensitive element is connected to the controller 49. This rotation sensor 7
0 detects the rotational position, rotational speed, etc. of the rotating shaft 61 and outputs a detection signal to the controller 49.

The motor case 60 also includes a motor chamber 3.
Three stator coils 62u, 62v, and 62w (represented by numbers without subscripts as necessary) constituting the stator are fixed on the left side of the first side, and a heat sink 66 is fixed on the right side. The three stator coils 62 are Y-connected (see FIG. 3), and three terminals are connected to a drive circuit described later.

The heat sink 66 is made of an extruded aluminum alloy member having a substantially hexagonal cylindrical shape with a hexagonal outer periphery;
A large number of cooling fins (not shown) are formed on the inner periphery. This heat sink 66 has bolts 9 passing through it in the axial direction.
8 is screwed onto the motor case 60 and fixed to the motor case 60, and the surrounding area is covered with a cover 65 made of resin. A resin 46 such as epoxy is filled between the cover 65 and the outer surface of the heat sink 66, and the cover 65 is fixed to the heat sink 66 with this resin. Note that the cover 65 has an air intake port connected to the air intake duct described above, and a board for a gate drive circuit, which will be described later, is disposed inside.

The heat sink 66 includes a total of six field effect transistors (FETs), one on each of the six outer surfaces.
ET) 35a, 35b, 35c, 35d, 35e, 35
f (hereinafter represented by a number without a subscript as necessary) constitutes a drive circuit (battery charging circuit) 64,
Further, a capacitor 68 for stabilizing the power supply is arranged on the inner periphery. Although not shown clearly in the figure, a cooling air passage communicating with the intake duct 88 is formed between the capacitor 68 and the inner peripheral portion of the heat sink 66, and the aforementioned cooling fins protrude into this cooling air passage.

The continuously variable transmission 53 is constructed by having a belt 74 suspended between a drive pulley 72 and a driven pulley 73. The drive pulley 72 is provided on the rotating shaft 61 of the electric motor 52, and the driven pulley 73 is a sleeve 7 rotatably provided on the input shaft 71 of the final reduction mechanism 54.
It can be attached to 8. This driven pulley 73 has a first centrifugal clutch 75 and a second centrifugal clutch 76 connected to the input shaft 71.
and are connected in parallel.

The drive pulley 72 is composed of a fixed face 72a fixed to the rotating shaft 61 and a movable face 72b provided on the rotating shaft 61 so as to be movable in the axial direction. This drive pulley 72 is driven by a governor mechanism 77 having a movable face 72b and a weight 77a to move in the axial direction, and the belt 7 is moved in accordance with the rotational speed of the rotating shaft 61.
The winding diameter of 4 changes.

Similarly, the driven pulley 73 is composed of a fixed face 73a fixed to the sleeve 78 and a movable face 73b supported by the sleeve 78 so as to be movable in the axial direction. The movable face 73b of the driven pulley 73 is biased toward the fixed face 73a by a spring 80a compressed between the movable face 73b and the clutch outer 79 of the second centrifugal clutch 76. The movable face 73b moves accordingly to change the belt winding diameter.

In the second centrifugal clutch 76, a clutch outer 79 is fixed to a sleeve 78, and a clutch inner 80 is provided on a clutch outer 81 of the first centrifugal clutch 75. This second centrifugal clutch 76 is similar to the first centrifugal clutch 7
5, the rotation speed of the clutch outer 81, that is, the rear wheel 14
Connect and disconnect according to the rotation speed of r. Further, in the first centrifugal clutch 75, the clutch outer 81 is fixed to the input shaft 71, the clutch inner 82 is provided on the clutch outer 79 of the second centrifugal clutch 76, and the rotational speed of the clutch outer 79 of the second centrifugal clutch 76 is That is, the electric motor 5
The connection and disconnection are performed according to the rotational speed of the second rotating shaft 61. The first centrifugal clutch 75 operates at a rotation speed slightly lower than the maximum efficiency rotation speed of the electric motor 52 (for example, 1700 rpm) and is connected in a region exceeding this rotation speed, and the second centrifugal clutch 76 It operates at a lower rotation speed (for example, 125 rpm) than the rotation speed at which it connects, and connects in a region exceeding this rotation speed.

The final reduction mechanism 54 includes a gear 71a fixed to the input shaft 71 and gears 83a, 83 fixed to the intermediate shaft 83.
b and a gear 84a fixed to the output shaft 84, with the gear 71a and the gear 83a meshing, and the gear 83b and the gear 84a meshing with each other. The input shaft 71 is connected to the case body 51 and the bearing member 57.
As mentioned above, the left end is the transmission chamber 5.
6 and is connected to the continuously variable transmission 53. Output shaft 84
protrudes to the right side of the case body 51, and the rear wheel 14r is fixed to the end of this output shaft 84.

The controller 49 is composed of an ECU and the like. As shown in FIG. 3, this controller 49 includes an accelerator sensor 37, a vehicle speed sensor 38, and a brake sensor 39.
, the voltage sensor 40 and the rotation sensor 70 described above are connected, and also connected to the gate drive circuit 41. The accelerator sensor 37 detects the operating angle of the accelerator grip,
Similarly, the vehicle speed sensor 38 detects the vehicle speed, the brake sensor 39 detects the operation of the brake pedal, and the voltage sensor 40 detects the voltage of the battery 36.

The controller 49 processes the output signals of each sensor and outputs pulse width modulation signals (corresponding to PWM signals and control pulse signals) a, b, c, d, e, and f. As will be described later, this controller 49 determines the braking state of the vehicle and outputs a predetermined PWM signal during braking according to the vehicle speed and the operating angle of the accelerator grip during normal driving (during driving excluding braking). A duty factor PWM signal is output to the gate drive circuit. Note that this PWM signal has a frequency that is more than twice the maximum frequency of an alternating current output by the electric motor during regenerative braking, which will be described later.

The gate drive circuit 41 includes a booster circuit and the like, and is connected to the battery 36 and the drive circuit 64. This gate drive circuit has a drive signal (
For convenience, the same symbol as the PWM signal is attached to the drive circuit 64.
output to FET35.

As shown in FIG. 3, the drive circuit 64 is formed by connecting the above-mentioned six FETs 35 in a bridge shape, and connects the positive terminal and the negative terminal (ground terminal) of the battery 36 in parallel with the above-mentioned capacitor 68. connected between. These F
The gate of ET35 is connected to the gate drive circuit 41, and the source of FET35a, the drain of FET35d, and FET35 are connected to the gate drive circuit 41.
Source of ET35b and drain of FET35e, FET
The source of FET 35c and the drain of FET 35f are connected to each other, and the drains of FETs 35a, 35b, 35c are connected to the positive terminal of battery 36,
The source of 5f is connected to the negative terminal. These FETs 35 each have diodes 42a, 42b,
42c, 42d, 42e, and 42f are connected in parallel.

Next, the operation of this embodiment will be explained. In this regenerative braking device, the program shown in FIG. 4 is repeatedly executed in the controller 49 to drive and control the electric motor 52.

First, in step P1, the duty factor (output duty) Do of the current applied to the electric motor 52 during normal running is calculated. This output duty Do is calculated based on the deviation between the operating angle of the accelerator grip and the vehicle speed.

In step P2, the value of the output duty Do is determined, and the braking state of the vehicle is determined based on the value of the output duty Do. In this step P2, if the output duty Do is a positive value (Do>0), it is determined to be a normal running state and the process of step P3 is performed, and if the output duty Do is zero (Do=0), it is determined to be a braking state. The determination is made and the process of step P4 is performed. Note that this step P2 is
This can be replaced by processing that determines the signal from the brake switch that detects the depression of the brake pedal.

In step P3, processing for energizing the electric motor, that is, PWM signals a, b, c
The duty factor of PWM signal a is set to 1, and the duty factors of PWM signals d, e, and f are set to Do above.
, b, c, d, e, and f are output to the gate drive circuit 41. Then, the gate drive circuit 41 outputs a drive signal corresponding to the PWM signal to each FET35, and outputs a drive signal corresponding to the PWM signal to each FET35.
5 is turned on/off according to the duty factor. Therefore, an alternating current having a phase difference of 120 degrees is applied to each stator coil 62 of the electric motor 52 (Fig.
1), the output of the electric motor 52 is transmitted to the rear wheels.

Further, in step P4, the voltage sensor 40
Determine the battery voltage Vb from the output signal of , and if the battery voltage exceeds a predetermined voltage, proceed to step P5, and if the battery voltage Vb is equal to or lower than the predetermined voltage V0, proceed to step P.
Perform the process in step 6. In addition. The above predetermined voltage V0 is the battery 3
This is the reference value for determining the necessity of charging battery 3.
It is determined as appropriate depending on the capacity etc. of 6.

In step P5, processing for performing dynamic braking is performed, that is, the duty factors of PWM signals a, b, c are set to 0, and the duty factors of PWM signals d, e, f are set to 1. The signal is output to the gate drive circuit 41. Therefore, the motor drive circuit 64 has FETs 35a, 35b, and 35c turned off, and FETs 35a, 35b, and 35c turned off.
35d, 35e, and 35 are turned on, making the terminals of the stator coil 62 conductive. Here, since the currents generated in each stator coil 62 have a phase difference of 120 degrees, the battery 3
Since no charging current flows through the battery 36, overcharging of the battery 36 can be prevented.

On the other hand, in step P6, the rotation speed of the electric motor 52 is determined from the output signal of the rotation sensor 70, and the regeneration duty Db is map searched from the data table shown in FIG. 10 using the rotation speed of the electric motor 52 as an address. do. Here, the data table of FIG. 10 is used because the deceleration torque exhibits a characteristic as shown in FIG. 9 with respect to the rotational speed of the electric motor 52 using the regeneration duty Db as a parameter. , is defined as a characteristic that increases the deceleration torque asymptotically to the regulation torque (torque over) as the rotational speed of the electric motor 52 increases. Note that the regulated torque in FIG. 9 is defined as the maximum transmission torque that can be transmitted without causing abnormality in the power transmission system such as the continuously variable transmission 53.

In the next step P7, output processing for performing regenerative braking is performed. The output processing of regenerative braking is P
The duty factor of WM signals a, b, c is 0, PWM
The duty factors of the signals d, e, and f are set to the regeneration duty Db, and these PWM signals are output to the gate drive circuit 41. Therefore, in the motor drive circuit 64, each FET 35a, 35b, 35c is turned off, and the FET 35
d, 35e, 35f are turned on/off according to the regeneration duty Db.
When the power is turned off, the electric power generated in the electric motor 52 is transferred to the battery 36.
In addition, the vehicle is braked with a deceleration torque according to the regenerative duty and the rotational speed of the electric motor 52.

Here, as shown in FIG. 11, a sinusoidal current is generated in each stator coil 62u, 62v, 62w of the electric motor 52, and the PWM signal is the maximum frequency of the alternating current generated by the electric motor 52. The FET has a frequency that is more than twice as high, and the FET turns on (
(The ON period is shown with diagonal lines). Therefore, the amount of heat generated by each stator coil 62u, 62v, and 62w can be made uniform.

Furthermore, during this regenerative braking, as is clear from FIGS. 9 and 10, the maximum value of the deceleration torque is regulated to a value smaller than the torque overload, so that the continuously variable transmission 5
In addition, since the deceleration torque increases as the rotational speed of the electric motor 52 increases, the electric motor 52
Braking performance during high-speed rotation is improved, and a good braking feeling is also obtained.

Furthermore, a first clutch 75 that responds to the rotational speed of the electric motor 52 and a second clutch 76 that responds to the rotational speed of the rear wheel 14r are connected in parallel between the electric motor 52 and the rear wheel 14r. The first clutch 75 is connected in a region where the maximum efficient rotation speed of the electric motor 52 exceeds the operating rotation speed, and the second clutch 76 is connected at a rotation speed lower than that of the first clutch 75. Connect in the area where the operating rotational speed exceeds the operating rotational speed. Therefore, the electric motor 52 can be operated efficiently to save power.
Furthermore, the kinetic energy of the vehicle body during braking can be effectively recovered.

The first clutch 75 and the second clutch 76 described above can be assembled to the rear wheel 14r as shown in FIG. 5a, or the clutches 75 and 76 can be assembled to the rear wheel 14r as shown in FIG. 52 is also possible. Furthermore, these clutches 75, 76 can be assembled to the rear wheel 14r together with the electric motor 52 as shown in FIG. . In a mode in which the final reduction mechanism 54 is assembled together with the final reduction mechanism 54, the reduction mechanism 54 is installed between the clutches 75, 76 and the electric motor 52 as shown in FIG.
It is possible to arrange the speed reduction mechanism 54 between the clutches 75, 76 and the rear wheel 14r as shown in FIG.

FIG. 8 shows another embodiment of the present invention. Note that the same parts as those in the above-mentioned embodiment are designated by the same reference numerals, and illustration and description thereof will be omitted. In this embodiment, a motor 43 is attached to the continuously variable transmission 53 as an actuator for changing the gear ratio, and this motor 94 adjusts the gear ratio of the continuously variable transmission 53.

As shown in FIG. 8, a sleeve 90 is provided on the rotating shaft 61 of the electric motor 52.
A movable face 73b of the drive pulley 72 is supported so as to be movable in the axial direction. A worm member 92 is engaged with the movable face 73b via a bearing 91 so as to be relatively rotatable and integrally movable in the axial direction.

The worm member 92 is formed with a gear portion 92a, and this gear portion 92a meshes with an intermediate gear 93. A worm 94a fixed to the rotating shaft of a motor 94 meshes with the intermediate gear 93. The motor 94 is connected to a drive circuit (not shown) and is driven based on a control signal output by the controller 49.

In this embodiment, during regenerative braking, the belt winding diameter of the drive pulley 72 is gradually reduced as the vehicle speed decreases, and the continuously variable transmission 53 is operated to decelerate, that is, the drive pulley 72 is moved from the driven pulley 73 to the drive pulley 72. Gradually increases the speed of rotation transmitted to the Therefore, even if the vehicle speed decreases,
The rotating shaft 61 of the electric motor 52 can be rotated at high speed, the efficiency of regenerative power generation can be improved, and the kinetic energy of the vehicle can be effectively recovered.

[0054]

As explained above, according to the invention as set forth in claim 1, the duty factor of the control pulse signal is reduced when the electric motor rotates at high speed, so that the braking force is reduced within a range where the braking force does not exceed a certain value. Since it is controlled so that it becomes large at high speeds, a good braking feeling can be obtained and a large braking force can be obtained at high speeds.

Further, according to the second aspect of the invention, since the power transmission system is provided with the first clutch that responds to the rotational speed of the electric motor, regenerative braking is ensured when the rotational speed of the electric motor is large. kinetic energy can be effectively recovered. In the invention according to claim 3, a second clutch responsive to the rotational speed of the drive wheel is provided in parallel with the first clutch, and the second clutch is connected at a lower rotational speed than the first clutch. As a result, the kinetic energy of the vehicle can be more effectively recovered during braking.

Furthermore, according to the invention set forth in claim 4,
Since the continuously variable transmission performs regenerative braking while decelerating, sufficient power can be generated even when the vehicle speed decreases, and energy can be effectively recovered.

[Brief explanation of the drawing]

[Fig. 1] Overall side view of an electric two-wheeled vehicle to which a regenerative braking device according to an embodiment of the present invention is applied.

[Figure 2] Cross-sectional view of the power unit of the regenerative braking device

[Figure 3] Electrical circuit diagram of the regenerative braking device

[Figure 4] Flowchart showing control processing of the regenerative braking device

[Fig. 5] A and b are schematic diagrams showing other aspects of the main parts of the regenerative braking device, respectively.

[Fig. 6] A schematic diagram showing another aspect of the main parts of the regenerative braking device.

[Fig. 7] A and b are schematic diagrams showing other aspects of the main parts of the regenerative braking device, respectively.

FIG. 8 is a sectional view of the main parts of a regenerative braking device according to another embodiment of the present invention.

[Fig. 9] A diagram showing the characteristics of the deceleration torque with respect to the rotational speed of the electric motor using the duty factor of the control signal as a parameter.

[Figure 10] Control characteristic diagram of duty factor of control signal

[Figure 11] Action explanatory diagram showing the current generated in the electric motor

[Explanation of symbols]

14r...Rear wheel (drive wheel), 35, 35a, 35b
, 35c, 35d, 35e, 35f...FET (switch element), 36... battery, 49... controller, 52... electric motor, 53... continuously variable transmission,
64...Motor drive circuit (battery charging circuit), 75
...first centrifugal clutch, 76...second centrifugal clutch.

Claims (4)

[Claims] Claim 1: A driving wheel is connected to a rotating shaft of an electric motor via a power transmission system, and a battery charging circuit is interposed between the electric motor and a battery, and a control pulse signal inputted by the battery charging circuit is provided. In a regenerative braking device for an electric vehicle that performs regenerative braking by turning on/off according to a duty factor of the electric motor, the duty factor of a control pulse signal input to the battery charging circuit is set to a high rotational speed according to the rotational speed of the rotating shaft of the electric motor. 1. A regenerative braking device for an electric vehicle, characterized in that the braking force is increased as the rotational speed of a rotating shaft increases within a range that does not exceed a predetermined braking force. 2. The regenerative braking device for an electric vehicle according to claim 1, wherein the power transmission system is provided with a first clutch that responds to the rotational speed of the rotating shaft of the electric motor, and the first clutch A regenerative braking device for an electric vehicle, characterized in that the power transmission system is cut off when the rotational speed of the rotating shaft is below a predetermined rotational speed. 3. The regenerative braking device for an electric vehicle according to claim 2, wherein a second clutch responsive to the rotational speed of the drive wheel is provided in the power transmission system in parallel with the first clutch. A regenerative braking device for an electric vehicle, characterized in that the second clutch is configured to connect the power transmission system in a rotational speed range exceeding a rotational speed smaller than the rotational speed at which the first clutch operates to disconnect. . 4. The regenerative braking device for an electric vehicle according to claim 1, wherein the power transmission system is provided with a continuously variable transmission, and while the continuously variable transmission is operated to shift toward a higher reduction ratio side, the battery is A regenerative braking device for an electric vehicle, characterized in that regenerative braking is performed by a charging circuit.