JP2018020579A - Steering wheel unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering wheel unit which is equipped with a dedicated battery for driving an electric motor and can charge the battery while driving.SOLUTION: Voltage of a vehicle battery 30 is taken out of an accessory socket and inputted to a charge circuit 33. The charge circuit 33 is composed of a charge voltage control circuit 37 which controls an upper limit charge voltage and stabilizes current flowing in a battery 18; and a changeover circuit 38 turning on/off charge of the battery 18 on the basis of a changeover signal s from an ECU 21. Power driving the electric motor 20 of an assist control mechanism 3 is supplied by the battery 18. When the electric motor 20 operates, the ECU 21 detects a steering state of the vehicle and outputs a signal turning on/off charge of the battery 18 with respect to the charge circuit 33. When a steering angle or steering angle velocity is determined to be specified value or smaller, the vehicle is determined to be driving straight ahead, the changeover circuit 38 is connected to turn on the charge; while turning, the changeover circuit 38 is disconnected to turn off the charge.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a steering wheel unit that can be attached to and detached from a vehicle together with a steering wheel.

  2. Description of the Related Art Conventionally, there is a type in which a steering wheel unit is detachably connected to a front end portion of a steering shaft of a vehicle and a steering assist force of assist means is applied to the steering wheel unit (see, for example, Patent Document 1). Such a steering wheel unit can be easily replaced and repaired, such as steering force detecting means, and can be easily maintained. Further, it is considered that the detection signal of the steering force detection means incorporated in the steering wheel unit by the signal extraction means can be taken out of the steering wheel unit.

Japanese Patent Laid-Open No. 3-159872

  In the steering wheel unit as described above, since the assist means is not incorporated, maintenance of the electric motor as the assist means is not easy. When the electric motor and the control means are housed in the steering wheel unit, it is necessary to supply power to the control means of the electric motor, a battery is detachably attached to the steering wheel unit, and there is no dedicated power wiring for the steering wheel unit May correspond to the vehicle. However, the assist operation cannot be continued if the remaining capacity of the battery decreases while the vehicle is running. For this reason, it is conceivable to use a large-capacity battery for the steering wheel unit or to prepare and replace a spare battery, but it is necessary to secure a place for installing a large-sized battery or to stop the vehicle Replacement is required. In addition, it is desirable to charge the battery when the battery is low, but if the battery is charged while traveling, depending on the steering state, for example, a large current may flow to the charging part such as a cable during turning, and it is necessary to make the fail safe. is there.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a steering wheel unit including a dedicated battery for driving an electric motor and capable of charging the battery while the vehicle is running. .

  In order to solve the above-mentioned problem, the invention according to claim 1 is a steering wheel unit attached to a vehicle having a steering mechanism that transmits a rotational drive of a steering shaft to a wheel and turns the steering wheel. A steering wheel shaft having one end connected to the steering wheel, and the other end provided with a detachable connecting portion to the steering shaft, an electric motor for giving a steering assist force to the steering wheel shaft, and the steering wheel A speed reduction mechanism that is attached to the shaft and transmits the rotation of the electric motor at a reduced speed, a torque sensor that detects a steering torque applied to the steering wheel shaft, and calculates the steering assist force based on the steering torque And drive control of the electric motor A control unit, the steering wheel shaft, the speed reduction mechanism unit, the electric motor, the torque sensor, and a housing that houses the control unit, and an external unit that supplies power to the control unit by charging from a DC power source of the vehicle The gist is provided with a power source, and a charging circuit unit that is connected between the DC power source and the external power source and controls charging of the external power source.

  According to the above configuration, the steering wheel unit includes the steering wheel, the steering wheel shaft, the housing, and the external power source. The housing has an electric motor and a controller fixed therein, and houses a speed reduction mechanism and a torque sensor attached to the steering wheel shaft. Further, an external power source that supplies power to the control unit and a charging circuit unit that controls charging of the external power source are fixed to the housing and connected to the control unit. Since the external power source is charged from the DC power source of the vehicle via the charging circuit unit, it is possible to charge the external power source while traveling. As a result, it is possible to reduce the size of the external power source, thereby improving the vehicle mountability, and it is not necessary to replace the external power source with a spare external power source since there is no battery exhaustion.

  According to a second aspect of the present invention, in the steering wheel unit according to the first aspect, the charging circuit unit is controlled by the control unit based on a steering angle and a steering angular velocity, and the vehicle is traveling straight ahead. The gist is to turn on the charging of the external power source and to turn off the charging of the external power source when the vehicle is turning.

  According to the above configuration, when the steering angle or steering angular velocity of the steering wheel during traveling is equal to or less than a predetermined value, the control unit determines that the vehicle is traveling straight ahead and connects the charging circuit unit to turn on charging of the external power source. During the turning of the vehicle, the charging circuit section is disconnected to turn off the charging of the external power source. For this reason, the external power source is not charged while the steering wheel is steered. As a result, a large current due to the operation of the electric motor does not flow between the direct current power source and the charging circuit unit of the vehicle, so that it is possible to achieve fail-safety.

  ADVANTAGE OF THE INVENTION According to this invention, the steering wheel unit which is equipped with the battery for exclusive use which drives an electric motor, and can charge a battery during vehicle travel can be provided.

The schematic diagram which shows schematic structure of the electric power steering apparatus which concerns on one Embodiment of this invention. The figure which shows schematic structure of the steering wheel unit of FIG. The figure which shows schematic structure of the external power supply attached to a steering wheel unit, and a charging circuit part periphery. The flowchart which shows the operation | movement process procedure of the charging circuit part performed by the control part.

Hereinafter, a steering wheel unit according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering apparatus 1 according to an embodiment of the present invention.
As shown in FIG. 1, the electric power steering apparatus 1 is for applying a steering assist force to a steering mechanism of a vehicle, and includes a steering mechanism 16 and a steering wheel unit 4. The steering mechanism 16 includes a steering shaft 6, a rack and pinion mechanism 14, a rack shaft 15, and two tie rods 10. The steering wheel unit 4 includes a steering wheel housing 24, a steering wheel 2, a steering wheel shaft 5, an assist control mechanism 3 that constitutes a steering assist mechanism, a deceleration mechanism (deceleration mechanism) 19, and a torque sensor 17. The assist control mechanism 3 includes an electric motor 20, an ECU (control unit) 21, a battery (external power source) 18, and a charging circuit (charging circuit unit) 33.

  In the steering mechanism 16, the steering shaft 6 includes a column shaft 7, an intermediate shaft 8, and a pinion shaft 9, and rotates integrally with the steering wheel shaft 5 as the steering wheel 2 rotates. The rack-and-pinion mechanism 14 has a pinion (pinion gear) 13 and a rack (rack gear) 12 that meshes with the pinion 13, and a rack shaft 15 that extends so that the rotation of the pinion shaft 9 cannot rotate and can move in the left-right direction of the vehicle. To reciprocal motion. Tie rods 10 are coupled to both ends of the rack shaft 15, and each tie rod 10 is connected to the steered wheels 11 via a knuckle arm (not shown).

  In the steering wheel unit 4, the steering wheel 2 is coupled to a steering wheel shaft 5 that is rotatably supported with respect to the steering wheel housing 24. An actuator including the speed reduction mechanism 19 and the electric motor 20 is attached to the steering wheel shaft 5 and applies a steering assist force (power) to the steering wheel shaft 5. The electric motor 20 that is a drive source of the actuator is connected to the steering wheel shaft 5 via a speed reduction mechanism 19 including an input pulley 25, an output pulley 26, and a belt 27 (both see FIG. 2), which will be described later. The rotational force of the electric motor 20 is decelerated by the speed reduction mechanism 19 and this reduced rotational force is transmitted to the steering shaft 6 as an assist torque.

  The electric motor 20 is controlled by an ECU 21 that constitutes an electronic control unit including a CPU (microcomputer). For example, a three-phase brushless motor is used. Further, the rotational speed of the rotation shaft of the electric motor 20 is calculated by the ECU 21 based on the rotation angle θm detected by the rotation angle sensor 22 such as a resorrelva built in the electric motor 20. The ECU 21 includes a control circuit including a CPU and a drive circuit (inverter) that is controlled by the control circuit and supplies electric power to the electric motor 20. Further, the external battery 18 is charged from the vehicle battery (DC power supply) 30 via the charging circuit 33, and electric power for driving the electric motor 20 is supplied from the battery 18 to the ECU 21.

  Further, the steering wheel unit 4 includes a torque sensor 17 that detects the steering torque τ by a relative rotational displacement amount between the input shaft (upper end side) and the output shaft (lower end side) of the steering wheel shaft 5 via a torsion bar (not shown). Have. The values detected by the torque sensor 17 including the rotation angle sensor 22 and the external vehicle speed sensor 23 for detecting the vehicle speed V, which is the vehicle speed, are input to the ECU 21 and processed.

  As described above, when the steering shaft 6 rotates via the steering wheel shaft 5 in accordance with the rotation operation of the steering wheel 2, the rack shaft 15 reciprocates in the axial direction by the rack and pinion mechanism 14. Thereby, the turning of the steered wheel 11 is achieved.

FIG. 2 is a diagram showing a schematic structure of the steering wheel unit 4 of FIG.
As shown in FIG. 2, the steering wheel unit 4 includes a steering wheel 2, a steering wheel shaft 5, a steering wheel housing 24, and a battery 18. The steering wheel shaft 5 is rotatably fixed to the steering wheel housing 24 and is connected to the steering wheel 2 at its upper end so as to rotate integrally around the axis. A column shaft 7 is fitted into the connecting portion at the lower end of the steering wheel shaft 5. The steering wheel shaft 5 and the column shaft 7 are connected with their axis centers aligned so as to rotate together.

  The steering wheel housing 24 covers the lower part of the steering wheel shaft 5 and is formed in a substantially rectangular parallelepiped shape. The electric motor 20 and the ECU 21 are fixed inside, and the speed reduction mechanism 19 and the torque sensor 17 attached to the steering wheel shaft 5 are accommodated. Is done. The electric motor 20 includes a rotation shaft and a rotation angle sensor 22 and is disposed so that the rotation shaft is substantially parallel to the steering wheel shaft 5. The torque sensor 17 is disposed around the steering wheel shaft 5.

  In the ECU 21, a signal line wiring cable 35 is connected by a connector 36 from an external device (for example, the vehicle speed sensor 23). The ECU 21 is connected to, for example, another ECU by a CAN signal and communicates with each other to exchange a steering command value, detection values of various sensors, other information necessary for motor control, and the like. A battery 18 for supplying electric power to the ECU 21 is externally fixed to the side surface of the steering wheel housing 24, and positive and negative electrode portions are connected to the ECU 21 by connectors (or relay cables). For the battery 18, for example, a DC power supply of DC12V is used. Further, a charging circuit 33 is attached in the steering wheel housing 24. The charging circuit 33 is supplied with the voltage of the vehicle battery 30 (see FIG. 1, for example, DC12V) via a charging connector 31 and a charging cable 32 connected to an accessory socket (for cigarette lighter) (not shown). A charging voltage is output from the battery 33 to the battery 18.

  The speed reduction mechanism 19 is a speed reduction mechanism portion including a pulley and a belt, and has a diameter larger than, for example, a toothed input pulley 25 connected to a rotating shaft of the electric motor 20 and an input pulley 25 connected to the steering wheel shaft 5. A toothed output pulley 26, and a toothed belt 27 spanned between the input pulley 25 and the output pulley 26. The input pulley 25 is coupled to the rotating shaft of the electric motor 20 so as to be integrally rotatable. The output pulley 26 is disposed on the outer periphery of the steering wheel shaft 5 so as to be integrally rotatable.

  When the rotating shaft of the electric motor 20 rotates, the input pulley 25 rotates accordingly. The rotation of the input pulley 25 is transmitted to the output pulley 26 via the belt 27, and the output pulley 26 rotates at a lower speed than the rotation of the input pulley 25.

Next, the attachment structure of the steering wheel unit 4 will be described.
As shown in FIG. 2, the steering wheel unit 4 is housed and fixed in a metal bracket 29 attached to a recess 34 that opens to the front surface (front side) of the dashboard 28 of the vehicle. The rear surface (back side surface) of the bracket 29 is connected to the column shaft 7 coupled to the steering wheel shaft 5, the wiring cable 35 on the other side of the ECU 21, and the connector 36.

  A battery 18 is attached to the side surface of the steering wheel housing 24. The battery 18 is fixed to the side surface of the steering wheel housing 24 (for example, screw fastening) in a state where a DC power source is accommodated in a resin case, for example, and is connected to the ECU 21 by a connector. A charging circuit 33 is attached in the steering wheel housing 24 and connected to the ECU 21. Charging circuit 33 is connected to external vehicle battery 30 by charging cable 32 and charging connector 31.

  Thus, the battery 18 can be used while being charged with the steering wheel unit 4 attached to the dashboard 28. As a result, there is no need to worry about running out of the battery, battery replacement is unnecessary, and the battery 18 can be reduced in size.

Next, FIG. 3 is a diagram showing a schematic configuration around the battery 18 and the charging circuit 33 attached to the steering wheel unit 4.
As shown in FIG. 3, the voltage of the vehicle battery 30 is taken out from a cigarette lighter accessory socket (not shown) installed at the lower center of the dashboard 28 (see FIG. 2) and input to the charging circuit 33 in the assist control mechanism 3. Is done. The charging circuit 33 controls an upper limit charging voltage to make the current flowing in the battery 18 constant, and a switching circuit 38 that turns on / off charging of the battery 18 based on a switching signal s from the ECU 21. Composed. The switching circuit 38 has a switching element such as a relay or FET.

  Next, FIG. 4 is a flowchart showing an operation processing procedure of the charging circuit 33 executed by the ECU 21. The control blocks (steps S401 to S404) shown below are realized by a program executed by the CPU of the ECU 21, and charging of the battery 18 is turned on / off by repeatedly executing each arithmetic process at predetermined intervals. Is done.

  In the assist control mechanism 3, power for driving the electric motor 20 is supplied from the battery 18 via the ECU 21. When the electric motor 20 is activated, the ECU 21 detects the steering state of the vehicle and outputs a switching signal s for turning on / off charging to the charging circuit 33.

  As shown in FIG. 4, during traveling of the vehicle, first, the CPU determines whether or not the steering angle is equal to or less than a predetermined value (step S401). If it is determined that the steering angle is equal to or less than the predetermined value (step S401: YES), it is determined that the steering wheel 2 is near neutral, and the process proceeds to step S402.

  If it is determined that the steering angle is greater than the predetermined value (step S401: NO), it is determined that the vehicle is turning (the steering wheel 2 is being steered), the switching circuit 38 is shut off, and charging is turned off (step). S403), the battery 18 is not charged. Thereafter, the CPU ends the processing and exits the flow.

  Subsequently, it is determined whether or not the steering angular velocity is equal to or less than a predetermined value (step S402). When it is determined that the steering angular velocity is equal to or less than the predetermined value (step S402: YES), it is determined that the steering is not performed, that is, the vehicle is traveling straight ahead, and the switching circuit 38 is connected to turn on charging (step (step S402). S404), the battery 18 is charged. Thereafter, the CPU ends the processing and exits the flow.

  When it is determined that the steering angular velocity is greater than the predetermined value (step S402: NO), the process proceeds to step S403, the switching circuit 38 is shut off and charging is turned off (step S403), and the battery 18 during vehicle turning is charged. Do not do it. This prevents a large current from flowing between the vehicle battery 30 and the charging circuit 33 during steering of the steering wheel 2 on which the electric motor 20 operates.

  Next, the operation and effect of the steering wheel unit 4 according to the present embodiment configured as described above will be described.

  According to the above configuration, the steering wheel unit 4 includes the steering wheel 2, the steering wheel shaft 5, the steering wheel housing 24, and the battery 18. In the steering wheel housing 24, the electric motor 20 and the ECU 21 are fixed, and the speed reduction mechanism 19 and the torque sensor 17 attached to the steering wheel shaft 5 are accommodated. Further, a battery 18 that supplies electric power to the ECU 21 is externally attached to the steering wheel housing 24, and a charging circuit 33 that controls charging of the battery 18 is fixed and connected to the ECU 21. Since the battery 18 is charged from the vehicle battery 30 via the charging circuit 33, the battery 18 can be charged during traveling.

  If the steering angle or the steering angular velocity of the steering wheel 2 that is traveling is equal to or less than a predetermined value, the ECU 21 determines that the vehicle is traveling straight ahead, connects the charging circuit 33 to turn on the battery 18, and turns on the vehicle. During the turning, the charging circuit 33 is disconnected and the charging of the battery 18 is turned off. For this reason, the battery 18 is not charged while the steering wheel 2 is steered.

  Thereby, since the battery 18 can be reduced in size, the vehicle mountability is improved, and the battery 18 does not run out, so that it is not necessary to replace the battery 18 with a spare battery 18. Further, since a large current due to the operation of the electric motor 20 does not flow between the vehicle battery 30 and the charging circuit 33, fail safe can be achieved.

  As described above, according to this embodiment, it is possible to provide a steering wheel unit that includes a dedicated battery that drives an electric motor and can be charged while the vehicle is running.

  Although one embodiment according to the present invention has been described above, the present invention can also be implemented in other forms.

  In the above embodiment, an example in which the battery 18 is externally fixed to the side surface of the steering wheel housing 24 has been described. However, the present invention is not limited to this, and the battery 18 may be mounted inside the steering wheel housing 24. Further, the charging circuit 33 may be integrally attached to the battery 18 outside the steering wheel housing 24.

  In the above embodiment, the example in which the output of the charging circuit 33 is switched by the switching signal s from the ECU 21 to turn on / off the charging of the battery 18 is shown, but the present invention is not limited to this. In addition, the output of the charging voltage to the battery 18 may be switched by determining whether the vehicle is traveling straight or turning based on the steering angle and steering angular velocity values transmitted from the ECU 21.

  In the above embodiment, a method for fixing the steering wheel unit 4 to the vehicle is not particularly described, but it is possible by appropriately attaching and fixing the steering wheel housing 24 to a space opened in the dashboard 28 facing the driver's seat. . For example, a plurality of thick metal plate-like claws are attached to the side surface of the steering wheel housing 24 of the steering wheel unit 4 so as to be able to be pushed and pushed out, and the brackets 29 are engaged and fixed. Good.

1: electric power steering device, 2: steering wheel, 3: assist control mechanism, 4: steering wheel unit, 5: steering wheel shaft,
6: steering shaft, 7: column shaft, 8: intermediate shaft, 9: pinion shaft, 10: tie rod, 11: steered wheel, 12: rack,
13: Pinion, 14: Rack and pinion mechanism, 15: Rack shaft,
16: Steering mechanism, 17: Torque sensor, 18: Battery (external power supply),
19: Deceleration mechanism (deceleration mechanism part), 20: Electric motor, 21: ECU (control part),
22: rotation angle sensor, 23: vehicle speed sensor,
24: Steering wheel housing (housing), 25: Input pulley,
26: output pulley, 27: belt, 28: dashboard, 29: bracket,
30: Vehicle battery (DC power supply), 31: Charging connector, 32: Charging cable,
33: charging circuit (charging circuit part), 34: recess, 35: wiring cable, 36: connector,
37: charging voltage control circuit, 38: switching circuit,
τ: steering torque, V: vehicle speed, θm: rotation angle, s: switching signal

Claims (2)

A steering wheel unit that is attached to a vehicle having a steering mechanism that transmits the rotational drive of a steering shaft to a wheel and steers it,
A steering wheel,
A steering wheel shaft having one end connected to the steering wheel and the other end provided with a detachable connecting portion to the steering shaft;
An electric motor for providing a steering assist force to the steering wheel shaft;
A speed reduction mechanism that is attached to the steering wheel shaft and decelerates and transmits the rotation of the electric motor;
A torque sensor for detecting a steering torque applied to the steering wheel shaft;
A control unit that calculates the steering assist force based on the steering torque, and drives and controls the electric motor;
A housing that houses the steering wheel shaft, the speed reduction mechanism, the electric motor, the torque sensor, and the control unit;
An external power source that is charged from a DC power source of the vehicle and supplies power to the control unit;
A steering wheel unit comprising: a charging circuit unit that is connected between the DC power source and the external power source and controls charging of the external power source. In the steering wheel unit according to claim 1,
The charging circuit unit is controlled by the control unit based on a steering angle and a steering angular velocity, and turns on charging of the external power source when the vehicle is traveling straight, and the external circuit when the vehicle is turning. A steering wheel unit characterized by turning off the charging of the power source.

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