JP5148657B2 - Accelerator pedal device - Google Patents

Description

  The present invention relates to an accelerator pedal device provided in a vehicle, and more particularly to an accelerator pedal device capable of generating a reaction force against a pedal effort.

  In an automobile that controls the throttle opening by operating the accelerator pedal installed in the vehicle, the valve body of the throttle valve is always spring-biased in the fully closed direction, and the accelerator pedal and the valve body of the throttle valve are connected by a wire. There is what I did. In this case, the driver can perform the depression operation of the accelerator pedal by sensing the spring urging force that increases according to the depression amount of the accelerator pedal as a reaction force of the accelerator pedal.

  Further, the accelerator pedal and the throttle valve are disconnected, and for example, a displacement sensor is provided on the accelerator pedal, and a valve element driving actuator is provided on the throttle valve to automatically control the throttle opening by the operation of the accelerator pedal. it can. In this case, since the spring biasing force on the throttle valve side does not act on the accelerator pedal, there is a type in which a return spring for returning the accelerator pedal to the initial position is directly assembled to the accelerator pedal.

  Further, in any of the above cases, there is an actuator provided with an actuator that generates a driving force in both the depression direction and the return direction with respect to the accelerator pedal. By using an electric motor as a power source for the actuator, it is possible to generate a driving force in both the stepping-in direction and the returning direction with a simple control of rotating the electric motor forward and backward. In this case, the depressing force of the accelerator pedal can be reduced by forward rotation of the electric motor, and can be increased by inversion.

  On the other hand, as an electric motor drive circuit for forward / reverse control of the electric motor, a pair of switching elements respectively provided on the power supply side and the ground side across the electric motor are arranged for forward rotation and reverse rotation, respectively. Such a bridge circuit is known (see, for example, Patent Document 1).

JP 2005-65396 A

  In the motor drive circuit using the bridge circuit as described above, the drive control of the electric motor is performed by an ECU (Electronic Control Unit) using a CPU, whereby the reaction force generation control by the electric motor can be suitably performed. . On the other hand, if the ECU continues to output an excessive output due to some cause such as noise, an overcurrent may flow through the electric motor. Since there is no possibility that the ECU is affected by external noise, a fuse is provided upstream of the bridge circuit (power supply line) as described in Patent Document 1 as a countermeasure.

  However, in the case of a circuit provided with a fuse upstream of the bridge circuit, if the fuse blows due to the overcurrent, even if the ECU returns to normal, the drive circuit becomes completely uncontrollable. In the meantime, there was a problem that the control by the addition of a suitable reaction force after that became impossible and the merchantability was lowered.

  In order to solve these problems, the accelerator pedal device that suitably applies reaction force by the motor actuator will take measures when an overcurrent occurs due to an abnormality in the control device and prevent all uncontrollable states when returning Therefore, in the present invention, in the accelerator pedal device including the electric motor (6b) that generates the driving force in both the depressing direction and the returning direction of the accelerator pedal (3) provided in the vehicle, A plurality of switching elements (8a, 8b, 9a, 9b) are provided so that a motor drive circuit (7) for controlling the drive of the electric motor causes the currents to flow through the electric motor to flow in opposite directions in the stepping direction and the return direction. And a fuse (12) for preventing an overcurrent from flowing through the electric motor, the fuse being Was assumed that only are arranged in the current path through the pair of switching elements (8a · 8b) for driving the electric motor to the depression direction of the bridge circuit.

  According to this, when the control device that controls the motor drive circuit continues to output an excessive output due to some cause, and an overcurrent in the direction of driving the electric motor flows in the depression direction of the accelerator pedal, It is possible to prevent the driving force from being generated in the stepping direction due to the blow of the fuse, and the current path interrupted by the fuse is only the current path flowing through the pair of switching elements for driving the electric motor in the stepping direction. For this reason, since the current path for driving the electric motor in the return direction is not interrupted, it is possible to control to generate a reaction force in at least the return direction when the ECU returns from the abnormal state to the normal state. The case where the reaction force is generated in the return direction is in response to the driver's depression operation of the accelerator pedal, and since it is possible to perform a suitable reaction force control against the depression, the merchantability of the accelerator pedal device that performs the reaction force control Can be prevented.

  In particular, the fuse (12) includes the electric motor (6b) and a pair of switching elements for driving the electric motor in the stepping direction (8b) provided on the ground side of the electric motor. It should be provided in between.

  Thus, according to the present invention, when the control device that controls the motor drive circuit continues to output an excessive output and an overcurrent flows through the electric motor, the reaction force is generated in the direction in which the accelerator pedal is depressed. In addition, since only the current path flowing through the electric motor is blocked by the fuse, it is possible to prevent the accelerator pedal from being lightened in the depression direction. Since the actuator can be controlled in the return direction of the accelerator pedal, it is possible to generate a reaction force when the driver depresses the accelerator pedal, and any reaction force control when the fuse is blown. However, the merchantability of the accelerator pedal device can be prevented from being reduced.

It is a side view which shows roughly the mechanical part of the accelerator pedal with which this invention was applied. It is a principal part circuit diagram which shows the motor drive circuit based on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view schematically showing a mechanical part of an accelerator pedal to which the present invention is applied. The accelerator pedal device of the illustrated example is shown as an example (drive-by-wire) that is not mechanically connected to a throttle valve of an engine (not shown). A known mechanically connected accelerator pedal device connected to the valve body via a wire may be used.

  As shown in FIG. 1, a floor panel 1 that forms a part of a vehicle is formed in a shape that rises to a predetermined height at a front portion of the vehicle, and a pedal support 2 is fixed to the rising portion 1a. The pedal support 2 supports the pedal arm 3a of the accelerator pedal 3 so as to be tiltable. The pedal support 2 is provided with an angle sensor 4 for detecting the tilt angle of the pedal arm 3a.

  The pedal arm 3a is spring-biased by a return spring 5 in a direction in which the pedal arm 3a is returned to the initial position indicated by the solid line in the figure corresponding to the fully closed state of the throttle opening. Further, the projecting end of the output rod 6a of the actuator 6 pivotally supported by the rising portion 1a is connected to the intermediate portion of the pedal arm 3a.

  The actuator 6 uses an electric motor 6b as a power source, and the accelerator rod 3 is accelerated and retracted by moving the output rod 6a in and out of the body of the actuator 6 by forward and reverse rotation of the electric motor 6b. It is provided so that the arm 3a can be driven. Thus, for example, when the accelerator pedal 3 is operated in the depression direction, the accelerator arm 3a is driven in the return direction in addition to the spring biasing force of the return spring 5 as a reaction force against the driver's depression force, and the accelerator pedal 3 is returned in the return direction. When operated, the accelerator arm 3a can be driven in the stepping direction against the spring biasing force of the return spring 5.

  As shown in FIG. 2, the motor drive circuit 7 that controls the drive of the electric motor 6b of the actuator 6 is connected in parallel to the battery line Lv connected to the battery (not shown) on the power source side and is connected to the electric motor 6b. Power supply side FETs 8a and 9a as switching elements respectively connected to the two terminals, and ground side FETs 8b and 9b as switching elements respectively connected to both terminals of the electric motor 6b and connected in parallel to the ground line Le. It is comprised by the well-known bridge circuit which provided. The on / off control of the FETs 8a, 8b, 9a, and 9b may be performed, for example, by PWM control by the ECU 11 incorporating the CPU.

  An angle detection signal corresponding to the amount of depression of the accelerator pedal 3 from the angle sensor 4 is input to the ECU 11, and further, current running condition signals from various sensors (engine rotation, vehicle speed, steering angle, yaw rate, etc.). It is good to be able to input. In the reaction force generation control for the accelerator pedal 3 by the ECU 11, when the electric motor 6b is driven in the depression direction of the accelerator pedal 3 (for example, normal rotation), one pair of FETs 8a and 8b on the power supply side and the ground side are turned on. The other pair of FETs 9a and 9b is turned off. On the contrary, when the electric motor 6b is driven (for example, reversely) in the return direction of the accelerator pedal 3, the one pair of FETs 8a and 8b are turned off, and the other pair of FETs 9a and 9b are turned on.

  In the motor drive circuit 7 of the illustrated example, the fuse 12 is connected between the electric motor 6b and the ground side FET 8b that is turned on when the electric motor 6b is driven in the depression direction of the accelerator pedal 3. When the electric motor 6b is driven in the depression direction of the accelerator pedal 3, as shown by the solid arrow (depression direction) in the figure, the power supply side FET 8a, the electric motor 6b, and the ground side FET 8b are arranged in this order from the power supply line Lv. A current flows through the electric motor 6b through a current path extending to the ground line Le. The fuse 12 is provided only in the current path when the electric motor 6b is driven in the depression direction of the accelerator pedal 3.

  The normal reaction force control in the accelerator pedal apparatus configured as described above will be described. When the accelerator pedal 3 is stepped on, the spring biasing force acting in the return direction by the return spring 5 increases as the accelerator pedal 3 is approached. When an operation of depressing the accelerator pedal 3 is performed, it is preferable that the driver feels an increase in the amount of depression of the accelerator pedal 3 due to a reaction force, but a large reaction force is long when traveling at a constant speed on an expressway, for example. Fatigue occurs as time goes on. In such a case, the accelerator pedal 3 can be operated with a light depression force by outputting a control command for generating a driving force in the depression direction of the accelerator pedal 3 from the ECU 11 to the electric motor 6b. It is also preferable to assist when the accelerator pedal 3 is stepped on all the way to the fully open position in order to quickly increase the vehicle speed and output. On the other hand, when the vehicle speed is high, such as when entering a curve, it is effective to increase the reaction force in order to make the driver recognize that the vehicle speed is to be reduced. In such a case, it is effective to return the accelerator pedal 3 in the return direction. Control to generate a driving force can be performed. In addition, control for applying a reaction force to the accelerator pedal 3 can be performed according to various traveling conditions.

  According to the arrangement of the fuse 12 described above, when the ECU 11 runs out of control for some reason and an overcurrent exceeding the rated current flows through the electric motor 6b, the electric motor is pushed in the depression direction of the accelerator pedal 3. The fuse 12 is blown only when 6b is driven. Since the fuse 12 is blown to prevent the actuator 3 from being driven in the direction in which the accelerator pedal 3 is depressed, a large driving force is applied to the depression of the accelerator pedal 3 when the ECU 11 runs out of control. It is prevented that the accelerator pedal 3 is greatly depressed with a light pedal force that is not intended.

  In addition, since the fuse 12 is provided only in the current path when the electric motor 6b is driven in the depression direction of the accelerator pedal 3 as described above, it is possible to prevent only the driving force from being applied in the depression direction. It is still possible to drive the electric motor 6b in the return direction. In this case, as shown by the two-dot chain line arrow (return direction) in FIG. 2, the current path from the power line Lv to the ground line Le via the power side FET 9a, the electric motor 6b, and the ground side FET 9b in this order. Since the current flows through the electric motor 6b, the current flows through the electric motor 6b in the direction opposite to the stepping direction, and the electric motor 6b is reversed.

  The return direction of the accelerator pedal 3 is the fully closed direction of the throttle opening, and the application of the driving force in that direction is a control that facilitates the operation of fully closing the throttle valve, and there is no problem. If the ECU 11 temporarily runs away due to a disturbance such as noise, the cause can be removed and the ECU 11 can return to the normal state. In such a case, if any reaction force control cannot be performed, the ECU 11 can be repaired. Until it is released, it will be forced to perform an uncomfortable accelerator operation that is different from the previous accelerator operation, so that the merchantability of the accelerator pedal device that realizes the preferable operation of the accelerator pedal 3 by applying a reaction force is reduced. There is a risk of doing.

  On the other hand, when an overcurrent occurs in the stepping direction, it prevents the generation of driving force in a direction in which the accelerator pedal 3 may be stepped on with a light stepping force. By leaving the force control, it is not possible to completely control the product before sending it out for repair.

  In the illustrated example, an FET is used as a switching element. However, the present invention is not limited to an FET, and any element having various switching functions such as a power transistor and a relay may be used. Further, the fuse 12 does not have to be a type that melts due to overcurrent, and may be a type that can be restored after being shut off like a thermostat.

3 Accelerator pedal 6b Electric motor 7 Motor drive circuit 8a, 8b Switching element (stepping direction)
9a, 9b Switching element (return direction)
12 Fuses

Claims (2)

In an accelerator pedal device including an electric motor that generates a driving force in both a depressing direction and a returning direction of an accelerator pedal provided in a vehicle,
A motor drive circuit that controls the driving of the electric motor includes a bridge circuit that uses a plurality of switching elements to flow currents flowing through the electric motor in opposite directions in the stepping direction and the return direction, and the electric motor. A fuse for preventing overcurrent from flowing;
The accelerator pedal device according to claim 1, wherein the fuse is disposed only in a current path passing through a pair of switching elements for driving the electric motor in the stepping direction of the bridge circuit.   The fuse is provided between the electric motor and a pair of switching elements for driving the electric motor in the stepping direction provided on the ground side of the electric motor. The accelerator pedal device according to claim 1.

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