JP4147420B2 - Vehicle power circuit - Google Patents

Description

  The present invention relates to a vehicle power supply circuit.

As an electric load mounted on the vehicle and supplied with power from a battery, for example, a manual valve that switches the oil passage of the automatic transmission control device is driven according to the driving range selected by the driver by operating a shift lever or shift switch, etc. Motor actuators are known.
Thus, in a so-called shift-by-wire type automatic transmission in which a manual valve is driven by a motor actuator and the oil passage of the automatic transmission control device is switched, when the parking range is selected, the parking of the manual valve is simultaneously performed by the driving of the motor actuator. The mechanism is activated and the output shaft of the vehicle is locked.

  In the case of an automatic transmission that manually locks the output shaft without using a motor actuator, even if the battery is completely discharged and the so-called battery has run out, the vehicle can be moved because the lock can be released manually. On the other hand, in the case of a shift-by-wire automatic transmission, if the battery runs out, power cannot be supplied to the motor actuator, so the lock cannot be released and the vehicle cannot move.

When the auxiliary battery (second battery) is provided, electric power can be supplied to the motor actuator and the output shaft can be unlocked even if the main battery (first battery) rises. In this case, when the main battery (first battery) rises, it is necessary to connect the auxiliary battery (second battery) immediately after the rise or at an appropriate timing after the rise.
In Patent Document 1, when the voltage of the second battery is detected and the control unit detects a decrease in the capacity of the second battery based on the detection result, the second battery is used to detect the presence of the vehicle occupant. The battery is charging.

JP 2001-145275 A

  However, according to the vehicle power supply circuit described in Patent Document 1, it is necessary to provide a means for detecting a voltage and a control unit to detect a decrease in capacity by detecting a voltage, which increases the cost. is there. Further, since charging is performed at the timing when the presence of the vehicle occupant is detected, it is necessary to provide a sensor for detecting the presence of the vehicle occupant, which further increases costs.

  The present invention has been created in view of such a problem, and when the first battery rises, the second battery can be connected with a simple configuration, and power is supplied to the electric load by the connected second battery. It is an object to provide a vehicle power supply circuit that can be supplied.

According to the first aspect of the present invention, the connection switching means is operated by a current flowing from the first battery to the electric load. Specifically, the connection switching means operates to cut off the connection between the second battery and the electric load by the current flowing from the first battery to the electric load. When the current stops flowing, the connection switching unit stops the operation for cutting off the connection, and the second battery and the electric load are connected. That is, when the first battery rises, the second battery is connected. Thus, according to this vehicle power supply circuit, the second battery can be connected when the first battery rises without providing means for detecting a decrease in the capacity of the first battery.
In addition, when the first battery rises and no current flows from the first battery to the electric load, the connection switching means connects the second battery to the electric load, so that the second battery is connected to the electric load. Simple.
Further, since the backflow prevention means prevents the backflow of current from the second battery to the first battery, the power of the second battery is supplied to the electric load when the second battery is connected. Therefore, according to this vehicle power supply circuit, the second battery can be connected with a simple configuration when the first battery is raised, and power can be supplied to the electric load by the connected second battery.

According to the invention described in claim 2, since the first battery and the second battery are connected in parallel, the electric power generated by the alternator can be stored not only in the first battery but also in the second battery.
According to the invention of claim 3, the overcharge of the second battery can be prevented by the overcharge prevention means for preventing overcharge.

According to the invention of claim 4, since the capacity of the second battery is smaller than the capacity of the first battery, the cost of the battery can be reduced.
According to the fifth aspect of the present invention, if the switch is turned off, the power of the first battery can be prevented from being consumed unnecessarily.

  According to the sixth aspect of the present invention, even if the first battery rises, the output shaft can be unlocked by driving the actuator of the shift-by-wire type automatic transmission with the second battery. Therefore, the vehicle can be moved even if the first battery rises.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 2 is a schematic diagram showing a part of the shift-by-wire automatic transmission 1. The manual valve 10 of this embodiment is switched by a motor actuator 11. The manual valve 10 is a spool type valve similar to a manual valve in an automatic transmission that switches the range by a conventional manual operation. The manual valve 10 is supplied with a line hydraulic pressure as a source pressure for control and driving, and each travel according to the shift position. A hydraulic pressure is supplied to a friction engagement device (not shown) through a path corresponding to the range.

The motor actuator 11 is connected to a vehicle power circuit described later via an SBW control ECU (shift-by-wire control electric control unit) 12. The rotation of the motor actuator 11 is transmitted to the control rod 13 through a fitting portion (not shown).
The control rod 13 is disposed perpendicular to the spool axis of the manual valve 10. A detent plate 14 is fixed to the control rod 13 so as to rotate integrally.

  The detent mechanism includes a detent plate 14 and a detent spring 15. The detent plate 14 is a plate-shaped member having a substantially fan shape, and a plurality of concave portions 14a are formed on the outer periphery of the arc shape. The detent spring 15 is a leaf spring and is fixed in a cantilever manner to a predetermined fixing portion. A roller 16 that engages with the recess 14 a of the detent plate 14 is attached to the tip of the detent spring 15, and the roller 16 engages with one of the recesses 14 a by the elastic force of the detent spring 15. The concave portion 14a and the roller 16 are arranged corresponding to the set positions of the respective ranges in the manual valve 10, and when the roller 16 is completely engaged with any one of the concave portions 14a, the travel range position corresponding to the concave portion 14a. The manual valve 10 is set to

  The parking lock mechanism is configured to stop the rotation of the output shaft by engaging the parking lock pole 18 with the uneven portion formed on the outer peripheral portion of the parking gear 17. The park rod 19 is bent at a substantially right angle, its base end is fixed to the detent plate 14, and its tip extends to a position opposite to the parking gear 17 with respect to the parking lock pole 18. A tapered cone-shaped cam 20 is fitted to the distal end portion of the park rod 19 so as to be movable back and forth and pressed in the distal direction by a spring 21. As the park rod 19 is moved forward, the cam 20 is pressed by the spring 21. As a result, the cam 20 pushes up the parking lock pole 18 toward the parking gear 17 so that the pawl 18a of the parking lock pole 18 is moved to the parking gear. 17 is configured to mechanically prevent rotation of the output shaft.

  The SBW control ECU 12 is connected to a range selection switch or a range selection lever (not shown) having switches corresponding to the parking range, reverse range, neutral range, drive range, 2 range, L range, and the like. The SBW control ECU 12 switches the shift range by rotating the motor actuator 11 according to the selected range.

Next, the vehicle power supply circuit will be described.
FIG. 1 is a schematic diagram of a vehicle power supply circuit. The vehicle power supply circuit 2 includes a main battery 31 as a first battery, an auxiliary battery 32 as a second battery, a relay 33 as a connection switching means, an overcharge prevention mechanism 35, and a backflow prevention diode as a backflow prevention means. 36 and 37 and the like, which are connected by a power line 30.

  The main battery 31 is connected to an alternator 34 provided in the vehicle, and stores electric power generated by the alternator 34. The main battery 31 is connected to the motor actuator 11 via the SBW control ECU 12 and supplies the stored electric power to the motor actuator 11 under the control of the SBW control ECU 12. Specifically, the main battery 31 is a lead storage battery that can be charged while generating electric power.

The various auxiliary machines 43 need to supply a certain amount of power even while the ignition switch is turned off. The main battery 31 always supplies power to various supplementary notes even when the ignition switch is off.
The auxiliary battery 32 is connected to the alternator 34 in parallel with the main battery 31 and stores the electric power generated by the alternator 34. The auxiliary battery 32 is connected to the motor actuator 11 via the SBW control ECU 12 when the main battery 31 is raised, and supplies the stored electric power to the motor actuator 11 under the control of the SBW control ECU 12. The auxiliary battery 32 is also a lead storage battery or the like like the main battery 31. The auxiliary battery 32 may have a smaller capacity than the main battery 31.

  The overcharge prevention mechanism 35 prevents the auxiliary battery 32 from being excessively charged. The overcharge prevention mechanism 35 is provided on the power supply line 30 that connects the + pole of the alternator 34 and the + pole of the auxiliary battery 32. The overcharge prevention mechanism 35 includes, for example, a relay or transistor, a current sensor, and an electronic control unit. The electronic control unit detects the charging current to the auxiliary battery 32 with a current sensor, and integrates this time to detect the charge amount of the auxiliary battery 32. When the charge amount is larger than a predetermined value, the auxiliary battery 32 is prevented from being excessively charged by turning off the relay or the transistor. A current sensor for detecting the discharge current may be provided to detect the charge amount based on the charge current and the discharge current. Note that it is possible to detect that the auxiliary battery 32 is fully charged by measuring the internal impedance of the auxiliary battery 32 and adjust the voltage generated by the alternator 34 to prevent overcharging. Techniques for preventing overcharging are well known, and how to prevent overcharging is a design matter that can be selected as appropriate.

  The backflow prevention diode 36 is provided on the power supply line 30 that connects the + pole of the alternator 34 and the overcharge prevention mechanism 35. The backflow prevention diode 37 is provided on the power supply line 30 that connects the positive electrode of the main battery 31 and a relay 33 described later. The backflow prevention diode 36 prevents backflow of current from the auxiliary battery 32 to the main battery 31. For this reason, even if the voltage of the main battery 31 decreases, the power stored in the auxiliary battery 32 is not supplied to the main battery 31. Therefore, even if the main battery 31 rises, power is stored in the auxiliary battery 32. Further, the backflow prevention diode 37 also prevents backflow of current from the auxiliary battery 32 to the main battery 31. For this reason, when the auxiliary battery 32 is connected to the motor actuator 11, the electric power stored in the auxiliary battery 32 is not supplied to the main battery 31 but is supplied to the motor actuator 11.

  The relay 33 is provided on the power supply line 30 that connects the positive electrode of the auxiliary battery 32 and the power supply terminal 12 a of the SBW control ECU 12. The relay 33 is turned on / off by a current flowing from the main battery 31 to the motor actuator 11. Specifically, the coil portion 33a of the relay 33 is formed by winding a power line 30 that connects the positive electrode of the main battery 31 and the power terminal 12a of the SBW control ECU 12 in a coil shape. The power supply line 30 extending from the power supply terminal 12a of the SBW control ECU 12 branches to the main battery 31 side and the auxiliary battery 32 side at the branch point 30a, and the coil portion 33a is provided on the main battery 31 side from the branch point 30a. . The relay 33 is a normally closed type, and the movable contact 33b is biased in a direction to turn on the relay 33 by a spring 33c. When a current flows from the main battery 31 to the SBW control ECU 12, that is, when the relay 33 is excited, the movable contact 33b is attracted to the coil portion 33a. Thereby, the relay 33 is turned off, and the connection between the auxiliary battery 32 and the SBW control ECU 12 is cut off. When no current flows from the main battery 31 to the SBW control ECU 12, that is, when the coil portion 33a is demagnetized, the movable contact 33b is urged by the spring 33c to return. Thereby, the relay 33 is turned on, and the auxiliary battery 32 and the SBW control ECU 12 are connected.

  The switch 42 is turned on when the ignition switch is turned on and turned off when the ignition switch is turned off. Since the main battery 31 may be connected to a battery that does not need to supply power while the ignition switch is turned off, the main battery 31 is provided with the switch 42 while the ignition switch is turned off. Can be prevented from being consumed unnecessarily. However, since the main battery 31 is also connected to various auxiliary machines 43, the main battery 31 may be lifted by the various auxiliary machines 43.

Next, the operation for unlocking the output shaft will be described when the main battery 31 is not raised and when the main battery 31 is raised.
(1) When the main battery 31 is not raised When the main battery 31 is not raised, power is supplied from the main battery 31 to the SBW control ECU 12 and the motor actuator 11 when the ignition switch is turned on. As a result, the relay 33 is turned off, and the connection between the auxiliary battery 32 and the SBW control ECU 12 is cut off. When the driver performs an operation of moving the range from parking to another range, the motor actuator 11 is driven by the electric power supplied from the main battery 31, and the parking lock is released.

(2) When the main battery 31 is raised If the main battery 31 is raised after the ignition switch is turned on, no current flows from the main battery 31 to the SBW control ECU 12, so that the relay 33 is turned on and the auxiliary battery is turned on. Power is supplied by 32. In this embodiment, when the ignition switch is turned off, the switch 42 is turned off and no current flows from the main battery 31, so the relay 33 is turned on and the auxiliary battery 32 is connected. For this reason, even if the main battery 31 rises while the ignition switch is off, power is supplied by the auxiliary battery 32. Since the backflow prevention diodes 36 and 37 prevent the backflow of current from the auxiliary battery 32 to the main battery 31, when the auxiliary battery 32 is connected, the electric power stored in the auxiliary battery 32 is the SBW control ECU 12 and the motor. This is supplied to the actuator 11 so that the driver can release the parking lock.

  According to the vehicle power supply circuit 2 according to the embodiment of the present invention described above, the relay 33 is operated by the current flowing from the main battery 31 to the motor actuator 11. Specifically, the relay 33 operates to disconnect the connection between the auxiliary battery 32 and the motor actuator 11 by the current flowing from the main battery 31 to the motor actuator 11. When the current no longer flows from the main battery 31 to the motor actuator 11, the coil portion 33a is demagnetized and the relay 33 stops the operation of disconnecting the connection, and the movable contact 33b is biased by the spring 33c, and the auxiliary battery 32 and the motor actuator 11 are stopped. And are connected. That is, when the main battery 31 rises, the auxiliary battery 32 is connected. Thus, according to the vehicle power supply circuit 2, the auxiliary battery 32 can be connected when the main battery 31 rises without providing a means for detecting a decrease in the capacity of the main battery 31. Therefore, the configuration for connecting the auxiliary battery 32 when the main battery 31 is raised is simple.

The schematic diagram of the power circuit for vehicles concerning one embodiment of the present invention. The schematic diagram which shows a part of automatic transmission which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic transmission, 2 Vehicle power supply circuit, 11 Motor actuator (electric load), 31 Main battery (1st battery), 32 Auxiliary battery (2nd battery), 33 Relay (connection switching means), 34 Alternator, 35 Overcharge prevention mechanism, 36 Backflow prevention diode (backflow prevention means), 37 Backflow prevention diode (backflow prevention means), 42 switch

Claims (6)

A first battery connected to an electrical load;
A second battery,
Connection switching means that is activated by a current flowing from the first battery to the electrical load, and disconnects the connection between the second battery and the electrical load when a current flows from the first battery to the electrical load. And connection switching means for connecting the second battery and the electric load when no current flows from the first battery to the electric load;
Backflow prevention means for preventing backflow of current from the second battery to the first battery;
A vehicle power supply circuit comprising: The first battery stores the electric power generated by the alternator,
2. The vehicle power supply circuit according to claim 1, wherein the second battery is connected in parallel to the first battery and stores electric power generated by the alternator.   The vehicle power supply circuit according to claim 2, further comprising overcharge prevention means for preventing overcharge of the second battery.   4. The vehicle power supply circuit according to claim 1, wherein the capacity of the second battery is smaller than the capacity of the first battery. 5.   The vehicular power supply circuit according to any one of claims 1 to 4, further comprising a switch on a power supply line connecting the first battery and the electric load. The vehicular power supply circuit according to any one of claims 1 to 5, wherein the electric load is an actuator of a shift-by-wire automatic transmission.

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