Motor drive circuit, actuator, and vehicle lamp

Abstract

A motor drive circuit for independently driving a three-phase motor (61) and a DC motor (71) comprises: a first circuit (C1) that drives the three-phase motor (61) and includes three half bridge circuits (HB1) to (HB3) connected in parallel with one another; and a second circuit (C2) that drives the DC motor (71) and includes two half bridge circuits (HB3), (HB4) connected in parallel with each other. One half bridge circuit (HB3) in the first circuit (C1) also serves as one half bridge circuit (HB3) in the second circuit (C2).

Description

Motor drive circuit, actuator, and vehicle lamp

[0001] The present invention relates to a motor drive circuit, an actuator, and a vehicle lamp.

[0002] There is known a vehicle lamp capable of changing the direction of a light exiting portion and changing the direction of exiting light by adjusting the vertical and horizontal leveling of an actuator. The following Patent Document 1 discloses a headlamp which is such a vehicle lamp.

[0003] In the vehicle headlamp disclosed in Patent Document 1 below, a leveling motor in a leveling drive unit is driven by a signal from a leveling ECU (Electronic Control Unit), so that the vertical direction of the light exiting portion is changed; a swivel motor in a swivel drive unit is driven by a signal from a swivel ECU, so that the horizontal direction of the light exiting portion is changed.

[0004] Japanese Patent No. 5523806

[0005] In the vehicle lamp described in Patent Document 1, the circuit is divided into two systems: one from the leveling ECU to the leveling motor, and the other from the swivel ECU to the swivel motor. For this reason, there has been a demand for reducing costs by integrating part of the circuit, and the present inventor has focused on the motor drive circuit and arrived at the present invention.

[0006] Accordingly, an object of the present invention is to provide a motor drive circuit, an actuator, and a vehicle lamp that can reduce costs.

[0007] To achieve the above objective, the present invention provides a motor drive circuit for individually driving a three-phase motor and a DC motor, comprising: a first circuit in which three half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in each half-bridge circuit are individually connected to three terminals of the three-phase motor to drive the three-phase motor; and a second circuit in which two half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in each half-bridge circuit are individually connected to two terminals of the DC motor to drive the DC motor, wherein one half-bridge circuit in the first circuit also serves as one half-bridge circuit in the second circuit.

[0008] Furthermore, in order to achieve the above objective, the present invention provides an actuator comprising: an upper-lower leveling drive unit that includes one of a three-phase motor and a DC motor and changes the vertical direction of a light emitting part that emits light to the outside of a vehicle; a left-right leveling drive unit that includes the other of the three-phase motor and the DC motor and changes the left-right direction of the light emitting part; a first circuit in which three half-bridge circuits, including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in each half-bridge circuit are individually connected to three terminals of the three-phase motor to drive the three-phase motor; and a second circuit in which two half-bridge circuits, including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in each half-bridge circuit are individually connected to two terminals of the DC motor to drive the DC motor, wherein one half-bridge circuit in the first circuit also serves as one half-bridge circuit in the second circuit.

[0009] Furthermore, in order to achieve the above objective, the present invention provides a vehicle lighting device comprising: a light emitting unit that emits light to the outside of the vehicle; an up-down leveling drive unit that includes one of a three-phase motor and a DC motor and changes the vertical direction of the light emitting unit; a left-right leveling drive unit that includes the other of the three-phase motor and the DC motor and changes the left-right direction of the light emitting unit; a first circuit in which three half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in each half-bridge circuit are individually connected to three terminals of the three-phase motor to drive the three-phase motor; and a second circuit in which two half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in each half-bridge circuit are individually connected to two terminals of the DC motor to drive the DC motor, wherein one half-bridge circuit in the first circuit also serves as one half-bridge circuit in the second circuit.

[0010] In such motor drive circuits, actuators, and vehicle lighting fixtures, a single half-bridge circuit serves as both a part of the first circuit that drives a three-phase motor and a part of the second circuit that drives a DC motor. Therefore, compared to cases where the motor drive circuit, actuator, and vehicle lighting fixtures completely separate the vertical motor drive circuit that drives the vertical motor used in the vertical actuator and the horizontal motor drive circuit that drives the horizontal motor used in the horizontal actuator, costs can be reduced.

[0011] Furthermore, when driving the DC motor with the high-side switch ON and the low-side switch OFF in the half-bridge circuits included in the first circuit and the second circuit, and the high-side switch OFF and the low-side switch ON in the half-bridge circuits not included in the first circuit, the high-side switch in at least one of the half-bridge circuits not included in the second circuit may be ON, and the low-side switches in each of the half-bridge circuits not included in the second circuit may be OFF.

[0012] In this case, while the DC motor is being driven, power can be supplied to the DC motor via the three-phase motor from at least one half-bridge circuit that is included in the first circuit but not in the second circuit. Therefore, when the DC motor is driven as described above, the movement of the DC motor can be accelerated, and the direction of the light emission part can be changed more quickly.

[0013] As described above, the present invention provides a motor drive circuit, actuator, and vehicle lighting device that can reduce costs.

[0014] Figure 1 shows a vehicle to which the vehicle lighting device of the present invention is applied. Figure 2 shows a vehicle lighting system including the vehicle lighting device. Figure 3 shows a circuit device and a leveling drive unit. Figure 4 shows the motor drive circuit and motor of Figure 3. Figure 5 is a timing chart showing the operation of the circuit device of Figure 3.

[0015] Preferred embodiments of the motor drive circuit, actuator, and vehicle lighting fixture according to the present invention will be described in detail below with reference to the drawings. The embodiments illustrated below are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved within the scope of the claims. In the drawings referenced below, the dimensions of each component may be shown differently for the sake of clarity. Also, in the drawings, for the sake of readability, reference numerals may be assigned to only some of the similar components, and some reference numerals may be omitted.

[0016] Figure 1 shows a vehicle to which the vehicle lighting system of the present invention is applied. As shown in Figure 1, the vehicle VE is equipped with a pair of vehicle lighting fixtures 100. The vehicle lighting system 1 is a system incorporated into the vehicle VE. In this embodiment, the example in which the vehicle lighting fixtures 100 are vehicle headlights will be described. In the figure, the X axis is the axis indicating the left-right direction, the Y axis is the axis indicating the up-down direction, and the Z axis is the axis indicating the front-back direction.

[0017] Figure 2 shows a vehicle lighting system 1 including the vehicle lighting fixture of this embodiment. As shown in Figures 1 and 2, the vehicle lighting system 1 of this embodiment mainly comprises a vehicle lighting fixture 100, a control signal output unit 3, a control unit 30, and a supply circuit 35.

[0018] First, the vehicle lighting fixture 100 will be described. The vehicle lighting fixture 100 of this embodiment mainly consists of a housing 120 and a lighting unit 130. In Figure 2, the housing 120 is shown in cross-section.

[0019] The housing 120 has a lamp housing 121 and a front cover 122. The front of the lamp housing 121 is open, and the front cover 122 is fixed to the lamp housing 121 so as to close this opening. The space formed by the lamp housing 121 and the front cover 122 is a housing space, and the luminaire unit 130 is housed in this housing space. The front cover 122 transmits the light emitted from the luminaire unit 130.

[0020] The lighting unit 130 of this embodiment mainly comprises a light-emitting section 140 equipped with a light source (not shown), an actuator AC, and a support member 160. Note that the internal structure of the light-emitting section 140 and the actuator AC is omitted in Figure 2.

[0021] The light emitting unit 140 emits light from the light source to the outside of the vehicle VE. In this example, the light emitted from the light emitting unit 140 is irradiated in front of the vehicle VE via the front cover 122. In this embodiment, the light emitting unit 140 can switch the emitted light between low beam and high beam. The light emitting unit 140 may also include a reflector that reflects light from the light source and a projection lens through which the light is transmitted. As a light source, for example, an LED array in which multiple LEDs (Light Emitting Diodes) are arranged in a matrix can be used. Furthermore, the light emitted by the light emitting unit 140 is not limited. For example, the light emitting unit 140 does not need to be able to switch the emitted light between low beam and high beam.

[0022] The actuator AC mainly comprises an up-and-down actuator AC1, a left-and-right actuator AC2, and a leveling drive circuit 4. The up-and-down actuator AC1 mainly comprises an up-and-down leveling drive unit 6 and a case 151, and is configured to change the direction of light emission from the light emission unit 140 in the up-and-down direction. The up-and-down leveling drive unit 6 is driven by the leveling drive circuit 4. In this embodiment, the up-and-down actuator AC1 is fixed to the housing 120. The up-and-down actuator AC1 may also be fixed to the housing 120 via other members. These other members are, for example, members that can be tilted relative to the housing 120 by operating a manual screw or the like. The up-and-down leveling drive unit 6 is located inside the case 151. An output shaft 153 is connected to the up-and-down leveling drive unit 6 and leads out to the front of the case 151. Power from the up-and-down leveling drive unit 6 can be transmitted to the output shaft 153. The output shaft 153 is a rod-shaped member extending in the front-rear direction and is movable along its longitudinal direction by power transmitted from the vertical leveling drive unit 6. The front end of the output shaft 153 has a ball-like shape.

[0023] The left / right actuator AC2 mainly comprises a left / right leveling drive unit 7 and a case 152, and is configured to change the direction of light emission from the light emission unit 140 in the left / right direction. The left / right leveling drive unit 7 is driven by a leveling drive circuit 4. In this embodiment, the left / right leveling drive unit 7 is located inside the case 152. An output shaft 154 is connected to the left / right leveling drive unit 7 and leads out to the top of the case 152. Power from the left / right leveling drive unit 7 can be transmitted to the output shaft 154. The output shaft 154 is a member that extends in the vertical direction and is rotatable around an axis that extends in the vertical direction by the power transmitted from the left / right leveling drive unit 7. The light emission unit 140 is fixed to the upper end of the output shaft 154. Therefore, when the output shaft 154 rotates, the light emission unit 140 rotates so that the direction of light emission changes in the left / right direction. A bracket 155 is provided on the bottom surface of the case 152, and the bracket 155 is rotatably connected to the front end of the output shaft 153.

[0024] The leveling drive circuit 4 is electrically connected to the vertical leveling drive unit 6 and the horizontal leveling drive unit 7, and drives the vertical leveling drive unit 6 and the horizontal leveling drive unit 7 as described above. The leveling drive circuit 4 may be located in the internal space of one of the cases 151 and 152, or outside the cases 151 and 152 in the internal space of the housing 120, or outside the housing 120. Details of the leveling drive circuit 4 will be described later.

[0025] The support member 160 is located above the light emitting section 140 and extends in the front-rear direction. The front end of the support member 160 has a ball shape, and a bracket 142 is rotatably connected to this front end. The bracket 142 is fixed to a plate section 143 that extends upward from the light emitting section 140. The front end of the support member 160 connected to the bracket 142 roughly coincides with the rotational axis of the output shaft 154 of the left-right actuator AC2.

[0026] In this type of lighting unit 130, the operation of the vertical actuator AC1 causes the output shaft 153 to move in the front-rear direction, increasing or decreasing its protrusion, which in turn causes the light-emitting section 140 and the horizontal actuator AC2 to tilt vertically around the front end of the support member 160 as a pivot point. As a result, the vertical orientation of the light-emitting section changes. Specifically, when the output shaft 153 moves forward and its protrusion increases, the light-emitting section 140 tilts upward, and when the output shaft 153 moves forward and its protrusion decreases, the light-emitting section 140 tilts downward. In addition, the operation of the horizontal actuator AC2 causes the output shaft 154 to rotate, which in turn causes the light-emitting section 140 to rotate around the axis of rotation of the output shaft 154. As a result, the horizontal orientation of the light-emitting section 140 changes.

[0027] The orientation of the light-emitting section 140 can be changed, for example, by 4 degrees upward and 5 degrees downward, and by 3 degrees left and right. The orientation of the light-emitting section 140 is adjusted by the leveling amounts of the vertical leveling drive section 6 and the horizontal leveling drive section 7, which are driven by the leveling drive circuit 4. The leveling drive circuit 4 is electrically connected to the control signal output unit 3 via the control signal cable 8 and is controlled by the control signal from the control signal output unit 3. The control signal output unit 3 is electrically connected to the control unit 30. The supply circuit 35 is electrically connected to the control signal output unit 3. In this specification and claims, electrical connections may be simply referred to as connections.

[0028] Next, the circuits and other components of the vehicle lighting system 1 of this embodiment will be described.

[0029] Figure 3 shows the circuit device and its respective leveling drive units in this embodiment. The circuit device 2 mainly comprises a control unit 30, a memory 31, a control signal output unit 3, a control signal cable 8, a leveling drive circuit 4, and a supply circuit 35. In this specification, at least one of the vertical leveling drive unit 6 and the horizontal leveling drive unit 7 may be referred to as the leveling drive unit.

[0030] First, the control unit 30, memory 31, supply circuit 35, and control signal output unit 3 will be described. These are installed, for example, in the ECU of a vehicle.

[0031] The control unit 30 consists of, for example, an integrated circuit (IC) such as a microcontroller, LSI (Large-scale Integrated Circuit), or ASIC (Application Specific Integrated Circuit), or an NC (Numerical Control) device. The control unit 30 may or may not use a machine learning machine. The control unit 30 is electrically connected to the control signal output unit 3, as well as the leveling drive circuit 4, the supply circuit 35, and the memory 31.

[0032] The memory 31 is configured to store information and to be readable. The memory 31 is, for example, a non-transitory recording medium, and semiconductor recording media such as RAM (Random Access Memory) or ROM (Read Only Memory) are preferred, but any type of recording medium such as optical recording media or magnetic recording media may be included. Note that a "non-transitory" recording medium includes computer-readable recording media excluding transient propagation signals, and does not exclude volatile recording media. The memory 31 stores programs and information necessary for the control unit 30 to control the control signal output unit 3, the leveling drive circuit 4, and the supply circuit 35. The control unit 30 reads the programs and information stored in the memory 31. The memory 31 may also store information upon instruction from the control unit 30.

[0033] The control unit 30 and memory 31 may be provided in the vehicle's ECU as described above, but at least one of the control unit 30 and memory 31 may be housed in the housing space of the housing 120. Alternatively, at least one of the control unit 30 and memory 31 may be provided on a circuit board on which the control signal output unit 3 is provided. Alternatively, the control unit 30 and memory 31 may be provided in a single package. Alternatively, at least one of the control unit 30 and memory 31 may be divided into multiple packages, for example, one part may be provided in the ECU and the other part may be provided in the internal space of the housing 120.

[0034] The supply circuit 35 is a circuit connected to a predetermined power source of the vehicle VE, and supplies power from that power source. This power is indicated by IG. The supply circuit 35 is a switch composed of, for example, a transistor, which supplies power from the predetermined power source when it is ON and stops supplying power from the predetermined power source when it is OFF. The supply circuit 35 is electrically connected to the leveling drive circuit 4 via a cable or the like. The voltage supplied to the supply circuit 35 is, for example, 12V. Therefore, the supply circuit 35 supplies power of this voltage to the leveling drive circuit 4. The location where the supply circuit 35 is provided is not particularly limited, but the supply circuit 35 may be provided, for example, on a circuit board on which the control signal output unit 3 is provided. Also, when the supply circuit 35 is provided on the ECU, the predetermined power source may be, for example, a constant voltage source that supplies power to the ECU.

[0035] The control signal output unit 3 mainly comprises a control signal output circuit 32, a ground switch 33, and a control-side connector 38.

[0036] The control signal output circuit 32 outputs a control signal to control the leveling drive circuit 4. The control signal in this embodiment is a voltage signal that controls based on a voltage value. Therefore, the control signal output circuit 32 outputs a control signal of a voltage value indicating the leveling amount by which the leveling drive circuit 4 drives the vertical leveling drive unit 6 and the horizontal leveling drive unit 7. The range of this voltage value is, for example, 0V to 16V. The control signal output circuit 32 is controlled by the control unit 30. The control signal output circuit 32 consists of, for example, a digital-to-analog conversion circuit. In this case, for example, when the control unit 30 outputs a control signal using a PWM (Pulse Width Modulation) signal to the control signal output circuit 32, the control signal output circuit 32 converts the PWM signal into a voltage value and outputs it. The control signal output circuit 32 is electrically connected to the control-side connector 38.

[0037] The control-side connector 38 is a connector to which one end of the control signal cable 8 can be plugged in and out. The control-side connector 38 is made of a conductor such as copper, and the contact surface of the control-side connector 38 with the control signal cable 8 may be gold-plated, but it may also be left unplated and the conductor such as copper exposed. The control signal cable 8 is, for example, a conductive cable with plugs on both ends, in which case the plugs are plugged in and out of the control-side connector 38.

[0038] A ground switch 33 is electrically connected to the control signal transmission path between the control signal output circuit 32 and the control-side connector 38 via a resistor r3. The ground switch 33 is a switch made of a transistor or the like, and is controlled by the control unit 30. The ground switch 33 is electrically connected to ground. Therefore, the ground switch 33 switches the electrical connection between the transmission path between the control signal output circuit 32 and the control-side connector and ground.

[0039] Next, we will explain the leveling drive circuit 4, the vertical leveling drive unit 6, and the horizontal leveling drive unit 7.

[0040] The leveling drive circuit 4 mainly comprises a protection circuit 41, a resistor r4, a comparator 42, a motor drive circuit 43, and a drive-side connector 48. The vertical leveling drive unit 6 mainly comprises a motor 61 and a position sensor 62.

[0041] The drive-side connector 48 has a configuration that is generally similar to that of the control-side connector 38, and the other end of the control signal cable 8 is a detachable connector. The drive-side connector 48 is electrically connected to the comparator 42 via a resistor r4. Therefore, the control signal output from the control signal output unit 3 and input to the leveling drive circuit 4 via the control signal cable 8 is input to the comparator 42 via the control-side connector 38 and resistor r4. Thus, the drive-side connector 48 to the comparator 42 is the transmission path for the control signal in the leveling drive circuit 4.

[0042] The comparator 42 is a circuit that compares the signal output from the position sensor 62 of the vertical leveling drive unit 6 (described later) and the signal output from the position sensor 72 of the horizontal leveling drive unit 7 (described later) with the control signal input from the drive-side connector 48, and outputs a different signal according to the result of the comparison. The comparator 42 is electrically connected to the control unit 30 and the motor drive circuit 43.

[0043] The motor drive circuit 43 is a circuit that drives the motor 61 of the vertical leveling drive unit 6 and the motor 71 of the horizontal leveling drive unit 7. Details of the motor drive circuit 43 will be described later.

[0044] The protection circuit 41 is electrically connected to the supply circuit 35 via a cable or the like. The protection circuit 41 consists of a diode D41 and a resistor r41 connected in series. The anode of diode D41 is electrically connected to the supply circuit 35, and the cathode is connected to one end of resistor r41. The other end of resistor r41 is connected to the transmission path of the control signal input from the drive-side connector 48, i.e., between the drive-side connector 48 and resistor r4. The resistance value of resistor r4 is, for example, 100 times or more that of resistor r41. In this way, the supply circuit 35 is connected to the transmission path of the control signal input from the drive-side connector 48 via the protection circuit 41.

[0045] A motor 61 of the vertical leveling drive unit 6 is connected to an output shaft 153 in FIG. 2 via a gear (not shown) or the like so as to be capable of transmitting power. When the torque of the motor 61 is transmitted to the output shaft 153 via a gear or the like, the output shaft 153 moves along the longitudinal direction, the protruding amount of the output shaft 153 from a case 151 changes, and as described above, the vertical orientation of a light emitting unit 140 changes. In the present embodiment, the motor 61 is a three-phase motor.

[0046] A position sensor 62 detects the position of the output shaft 153. The position sensor 62 is formed of, for example, a potentiometer. Note that the position sensor 62 may detect the position of the output shaft 153 by detecting the rotation amount of the motor 61. The position sensor 62 is electrically connected to a comparator 42 of a leveling drive circuit 4, and outputs a detection signal to the comparator 42.

[0047] A motor 71 of the horizontal leveling drive unit 7 is connected to an output shaft 154 in FIG. 2 via a gear (not shown) or the like so as to be capable of transmitting power. When the torque of the motor 71 is transmitted to the output shaft 154 via a gear or the like, the output shaft 154 rotates about its axis, and the horizontal orientation of the light emitting unit 140 changes. In the present embodiment, the motor 71 is a DC motor.

[0048] A position sensor 72 detects the rotational position of the output shaft 154. The position sensor 72 is formed of, for example, a potentiometer similarly to the position sensor 62. Note that the position sensor 72 may detect the rotational position of the output shaft 154 by detecting the rotation amount of the motor 71. The position sensor 72 is electrically connected to the comparator 42 of the leveling drive circuit 4, and outputs a detection signal to the comparator 42.

[0049] Next, the motor drive circuit 43 will be described.

[0050] FIG. 4 is a diagram showing the motor drive circuit 43 and the motors 61, 71.

[0051] As shown in Figure 4, the motor drive circuit 43 mainly comprises four half-bridge circuits HB1 to HB4. Half-bridge circuit HB1 includes a high-side switch QUH and a low-side switch QUL connected in series with each other. Similarly, half-bridge circuit HB2 includes a high-side switch QVH and a low-side switch QVL connected in series with each other, half-bridge circuit HB3 includes a high-side switch QWH and a low-side switch QWL connected in series with each other, and half-bridge circuit HB4 includes a high-side switch QXH and a low-side switch QXL connected in series with each other. Each of the high-side switches QUH to QXH and the low-side switches QUL to QXL is composed of transistors or the like. The control unit 30 controls the switching of each of the half-bridge circuits HB1 to HB4.

[0052] In each of the half-bridge circuits HB1 to HB4, the terminals on the opposite side of the low-side switches QUL to QXL from the high-side switches QUH to QXH are electrically connected to each other and are also connected to a predetermined power supply. This power supply is indicated as DC. In addition, the terminals on the opposite side of the high-side switches QUL to QXL from the high-side switches QUH to QXH are electrically connected to each other and are also connected to ground. Thus, each of the half-bridge circuits HB1 to HB4 is connected to each other in parallel.

[0053] As described above, since the motor 61 is a three-phase motor, it has three terminals 61U to 61W. The circuit between the high-side switch QUH and the low-side switch QUL of the half-bridge circuit HB1 is electrically connected to terminal 61U of the motor 61. Similarly, the circuit between the high-side switch QVH and the low-side switch QVL of the half-bridge circuit HB2 is electrically connected to terminal 61V of the motor 61, and the circuit between the high-side switch QWH and the low-side switch QWL of the half-bridge circuit HB3 is electrically connected to terminal 61W of the motor 61.

[0054] Thus, a three-phase full-wave rectifier circuit is formed by the first circuit C1, which consists of half-bridge circuits HB1 to HB3, and the motor 61. Therefore, the half-bridge circuits HB1 to HB3 are energized and driven, for example, at 120 degrees. For example, the high-side switch QUH is turned on when the rotation angle of the motor 61 is from 0 to 120 degrees, the high-side switch QVH is turned on when the rotation angle is from 120 to 240 degrees, the high-side switch QWH is turned on when the rotation angle is from 240 to 360 degrees, the low-side switch QUL is turned on when the rotation angle of the motor 61 is from 180 to 300 degrees, the low-side switch QVL is turned on when the rotation angle is from 300 to 60 degrees, and the low-side switch QWL is turned on when the rotation angle is from 60 to 180 degrees. In this case, the rotation angle of the motor 61 is detected by a magnetic sensor (not shown), and based on the detection result, the control unit 30 controls the respective half-bridge circuits HB1 to HB3 depending on the initial state of the rotation angle of the motor 61 and the direction of rotation. As long as the half-bridge circuits HB1 to HB3 are switching and the motor 61 is rotating, the half-bridge circuits HB1 to HB3 may be driven in a different manner than described above. Furthermore, while the half-bridge circuits HB1 to HB3 are switching and the motor 61 is rotating, the control unit 30 turns off the high-side switch QXH and the low-side switch QXL of the half-bridge circuit HB4.

[0055] As described above, since motor 71 is a DC motor, it has two terminals 71W and 71X. The circuit between the high-side switch QXH and the low-side switch QXL of the half-bridge circuit HB4 is electrically connected to terminal 71X of motor 71. As described above, the circuit between the high-side switch QWH and the low-side switch QWL of the half-bridge circuit HB3, which is electrically connected to terminal 61W of motor 61, is further electrically connected to terminal 71W of motor 71.

[0056] Thus, a full-bridge circuit is formed by the second circuit C2, which consists of half-bridge circuits HB3 and HB4, and the motor 71. The half-bridge circuits HB3 and HB4 are driven in reverse direction. That is, when the motor 71 rotates in one direction, the high-side switch QWH is turned on, the high-side switch QXH is turned off, the low-side switch QWL is turned off, and the low-side switch QXL is turned on. When the motor 71 rotates in the other direction, the high-side switch QWH is turned off, the high-side switch QXH is turned on, the low-side switch QWL is turned on, and the low-side switch QXL is turned off. As long as the half-bridge circuits HB3 and HB4 are operating and the motor 71 is rotating, the half-bridge circuits HB3 and HB4 may be controlled differently from the above. Furthermore, while the half-bridge circuits HB3 and HB4 are in a predetermined switch state and the motor 71 is rotating, the high-side switches QUH and QVH and the low-side switches QUL and QVL of the half-bridge circuits HB1 and HB2 are turned off.

[0057] As described above, the first circuit C1 consists of half-bridge circuits HB1 to HB3, and the second circuit C2 consists of half-bridge circuits HB3 and HB4. Therefore, one half-bridge circuit HB3 serves as both one half-bridge circuit in the first circuit C1 and one half-bridge circuit in the second circuit C2.

[0058] Next, the operation of the circuit device 2 will be explained.

[0059] Figure 5 is a timing chart showing the operation of the circuit device 2. Figure 5 shows the voltage of the power output from the supply circuit 35, the drive switching state of the first circuit C1 or the second circuit C2 by the control unit 30, the state of the control signal output from the control signal output circuit 32, the connected / disconnected state of the ground switch 33, the operation of the first circuit C1, the operation of the second circuit C2, and the current flowing through the control signal cable 8. An example of 12V is shown as the power output from the supply circuit 35 in Figure 3. The drive switching state of the first circuit C1 or the second circuit C2 by the control unit 30 is indicated as the motor drive circuit, where C1 indicates that the first circuit C1 is operational, C2 indicates that the second circuit C2 is operational, and the state in between indicates that neither is operational. The control signal output from the control signal output circuit 32 indicates that a control signal is output if it is ON, and a control signal is not output if it is OFF. The ground switch 33 is indicated as GNDs / w, where it is connected if it is ON, and disconnected if it is OFF. The first circuit C1 and the second circuit C2 are operating when ON and not operating when OFF. The current flowing through the control signal cable 8 is shown as follows: the dashed line indicates 0A, the area above the dashed line indicates that current is flowing from the control signal output unit 3 to the leveling drive circuit 4, and the area below the dashed line indicates that current is flowing from the leveling drive circuit 4 to the control signal output unit 3. The further away from the dashed line, the higher the current value.

[0060] As shown in Figure 5, in this example, the supply circuit 35 always supplies power from a predetermined power source. Therefore, the power from the supply circuit 35 is supplied to the control signal transmission path in the leveling drive circuit 4 via the protection circuit 41.

[0061] At time T1, the control unit 30 enables the operation of the first circuit C1 and prevents the operation of the second circuit C2. This control is completed within the control unit 30, and no signal is output from the control unit 30. Also at time T1, the control unit 30 controls the control signal output circuit 32 to output a control signal. Furthermore, at time T1, the control unit 30 controls the ground switch 33 to disconnect it. Consequently, the control signal transmission path is ungrounded. Therefore, the control signal output from the control signal output circuit 32 is input to the leveling drive circuit 4 from the drive-side connector 48 via the control-side connector 38 and the control signal cable 8. Consequently, current due to the control signal flows from the control signal output unit 3 to the leveling drive circuit 4 in the control signal cable 8. The current value at this time is, for example, 0.01 mA or more and 0.2 mA or less.

[0062] When a control signal is input to the comparator 42, the comparator 42 compares the signal from the position sensor 62 with the control signal and outputs a signal related to the comparison result to the control unit 30, which then operates the first circuit C1 of the motor drive circuit 43. The operation of the first circuit C1 causes the motor 61 to operate. The operation of the motor 61 causes the output shaft 153 to move along its longitudinal direction, and the orientation of the light emitting unit 140 changes in the vertical direction. Therefore, the direction of the light emitted from the light emitting unit 140 changes in the vertical direction. When the output shaft 153 moves by a predetermined amount due to the operation of the motor 61, the signal from the position sensor 62 and the control signal become, for example, the same voltage. At this time, the comparator 42 outputs a different signal to the control unit 30. Upon receiving this signal, the control unit 30 stops the operation of the first circuit C1. In this example, the first circuit C1 stops at time T11. Therefore, the operation of the motor 61 stops at time T11. The duration of operation of the first circuit C1 varies depending on the voltage of the control signal, but is, for example, between 0.5 and 6 seconds.

[0063] The period from time T1 to time T2 is the transmission period of the control signal, which is longer than the operation period of the first circuit C1, for example, 13 seconds. Therefore, at time T2, the motor 61 is stopped. At time T2, the control unit 30 does not make the first circuit C1 and the second circuit C2 operational. Also at time T2, the control unit 30 controls the control signal output circuit 32 to stop the output of the control signal from the control signal output circuit 32, and further controls the ground switch 33 to connect the ground switch 33. Therefore, the control signal transmission path in the control signal output unit 3 is grounded. As a result, the power supplied from the supply circuit 35 to the control signal transmission path of the leveling drive circuit 4 flows from the drive-side connector 48 to the control signal cable 8, and further flows from the control-side connector 38 to the control signal output unit 3, and then flows to the ground via the ground switch 33. As a result, a refresh current with a current value larger than the current that flows through the control signal cable 8 due to the control signal during the period from time T1 to time T2 flows through the control signal cable 8. Therefore, even if a small oxide film is formed on the control-side connector 38 or the drive-side connector 48, this oxide film can be destroyed by the refresh current. Furthermore, the refresh current suppresses the formation of the oxide film. The refresh current is, for example, 1 mA or more.

[0064] Next, at time T3, the control unit 30 makes the second circuit C2 operational and prevents the first circuit C1 from operating. Also at time T3, the control unit 30 controls the control signal output circuit 32 to output a control signal, and further controls the ground switch 33 to disconnect it. Consequently, the control signal transmission path becomes ungrounded. Therefore, the control signal output from the control signal output circuit 32 is input to the leveling drive circuit 4, just as it was from time T1 to time T2. As a result, current due to the control signal flows through the control signal cable 8 from the control signal output unit 3 to the leveling drive circuit 4.

[0065] When a control signal is input to the comparator 42, the comparator 42 compares the signal from the position sensor 72 with the control signal and outputs a signal related to the comparison result to the control unit 30, which then operates the second circuit C2 of the motor drive circuit 43. The operation of the second circuit C2 causes the motor 71 to operate. The operation of the motor 71 causes the output shaft 154 to rotate, and the orientation of the light emitting unit 140 changes in the left-right direction. Therefore, the direction of the light emitted from the light emitting unit 140 changes in the left-right direction. When the output shaft 154 rotates by a predetermined amount due to the operation of the motor 71, the signal from the position sensor 72 and the control signal become, for example, the same voltage. At this time, the comparator 42 outputs a different signal to the control unit 30. Upon receiving this signal, the control unit 30 stops the operation of the second circuit C2. In this example, the second circuit C2 stops at time T31. Therefore, the operation of the motor 71 stops at time T31. The duration of operation of the second circuit C2 varies depending on the voltage of the control signal, but is, for example, between 0.5 and 6 seconds.

[0066] The period from time T3 to time T4 is the transmission period of the control signal, which is longer than the operation period of the second circuit C2, for example, 13 seconds. Therefore, at time T4, the motor 71 is stopped. At time T4, the control unit 30 sets the motor drive circuit 43, the control signal output circuit 32, and the ground switch 33 to the same state as from time T2 to time T3. As a result, a refresh current with a current value greater than the current that flows through the control signal cable 8 due to the control signal during the period from time T3 to time T4 flows through the control signal cable 8. Therefore, as with the period from time T2 to time T3, even if a small oxide film is formed on the control-side connector 38 and the drive-side connector 48, this oxide film can be destroyed by the refresh current. In this way, the state becomes the same as the state before time T1.

[0067] As described above, the motor drive circuit 43 of this embodiment is a motor drive circuit that drives a three-phase motor 61 and a DC motor 71 individually, and comprises a first circuit C1 in which three half-bridge circuits are connected in parallel to each other, and the electrical circuits between the high-side switches QUH to QWH and the low-side switches QUL to QWL in each half-bridge circuit HB1 to HB3 are individually connected to the three terminals 61U to 61W of the three-phase motor 61 to drive the three-phase motor 61, and a second circuit C2 in which two half-bridge circuits HB3 and HB4 are connected in parallel to each other, and the electrical circuits between the high-side switches QWH and QXH and the low-side switches QWL and QXL in each half-bridge circuit HB3 and HB4 are individually connected to the two terminals 71W and 71X of the DC motor 71 to drive the DC motor 71, and one half-bridge circuit HB3 in the first circuit C1 also serves as one half-bridge circuit HB3 in the second circuit C2. Furthermore, the actuator AC of this embodiment includes a three-phase motor 61 and an up-down leveling drive unit 6 that changes the vertical direction of the light emitting unit 140, a left-right leveling drive unit 7 that includes a DC motor 71 and changes the left-right direction of the light emitting unit 140, and the motor drive circuit 43. Furthermore, the vehicle lighting fixture 100 of this embodiment includes the light emitting unit 140 and the actuator AC.

[0068] With this motor drive circuit 43, actuator AC, and vehicle lighting fixture 100, one half-bridge circuit HB3 serves as both a part of the first circuit C1 that drives the three-phase motor 61 and a part of the second circuit C2 that drives the DC motor 71. Therefore, with the motor drive circuit 43, actuator AC, and vehicle lighting fixture 100, costs can be reduced compared to the case where the vertical motor drive circuit that drives the vertical motor used in the vertical actuator AC1 and the horizontal motor drive circuit that drives the horizontal motor used in the horizontal actuator AC2 are completely separated.

[0069] Although the present invention has been described above with reference to the above embodiments, the present invention is not limited thereto.

[0070] For example, in the above embodiment, the motor 61 of the vertical leveling drive unit 6 is a three-phase motor, and the motor 71 of the left-right leveling drive unit 7 is a DC motor. However, the motor 61 of the vertical leveling drive unit 6 may be a DC motor, and the motor 71 of the left-right leveling drive unit 7 may be a three-phase motor. In this case, the half-bridge circuits HB1 to HB3 of the first circuit C1 are electrically connected to the three terminals of the motor 71, and the first circuit C1 drives the motor 71, and the half-bridge circuits HB3 and HB4 of the second circuit C2 are electrically connected to the two terminals of the motor 61, and the second circuit C2 drives the motor 61. Generally, the vertical actuator AC1 is driven more frequently than the left-right actuator AC2. Therefore, as in the above embodiment, it is preferable that a three-phase motor is used for the motor 61 of the vertical leveling drive unit 6 and a DC motor is used for the motor 71 of the left-right leveling drive unit 7.

[0071] Furthermore, the timing chart of the above embodiment is just one example, and different control methods may be used as long as the motor 61 is driven when changing the orientation of the light emitting unit 140 in the vertical direction, and the motor 71 is driven when changing the orientation in the horizontal direction.

[0072] Furthermore, in the above embodiment, when the DC motor 71 is driven, the high-side switches QUH, QVH and low-side switches QUL, QVL of the half-bridge circuits HB1 and HB2, which are not included in the second circuit C2 that drives the motor 71, are turned off. However, when the DC motor 71 is driven with the high-side switch QWH on and the low-side switch QWL off in the half-bridge circuit HB3, which is included in the first circuit C1 and the second circuit C2, and the high-side switch QXH off and the low-side switch QXL on in the half-bridge circuit HB4, which is not included in the first circuit C1, the high-side switches QUH, QVH in at least one of the half-bridge circuits HB1 and HB2, which are not included in the second circuit C2, may be turned on, and the low-side switches QUL, QVL in each of the half-bridge circuits HB1 and HB2, which are not included in the second circuit C2, may be turned off. In this case, while the DC motor 71 is being driven, power can be supplied to the DC motor 71 via the three-phase motor 61 from at least one of the half-bridge circuits HB1 and HB2, which are included in the first circuit C1 but not in the second circuit C2. Therefore, when the DC motor 71 is driven in this way, the movement of the DC motor 71 can be accelerated, and the direction of the light emitting section 140 can be changed more quickly. When driving in this way, it is preferable to lock the three-phase motor 61 so that it does not operate.

[0073] Furthermore, the configuration of the vehicle lighting fixture 100 may differ from that shown in Figure 2, as long as it includes a light emitting unit 140, an up / down actuator AC1, and a left / right actuator AC2. For example, the configuration of the output shafts 153 and 154, and the configuration of the brackets 142 and 155, etc., may differ from that shown in Figure 2.

[0074] Furthermore, in the above embodiment, a vehicle headlight was used as an example of the vehicle lighting device 100. However, the vehicle lighting device 100 is not limited to a vehicle headlight, and may be, for example, a road surface drawing device that draws a predetermined image on the road surface with emitted light.

[0075] According to the present invention, a motor drive circuit, actuator, and vehicle lighting equipment that can reduce costs are provided and can be used in fields such as vehicle lighting equipment for automobiles.

Claims

1. A motor drive circuit for individually driving a three-phase motor and a DC motor, comprising: a first circuit in which three half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switches and the low-side switches in the three half-bridge circuits are individually connected to three terminals of the three-phase motor to drive the three-phase motor; and a second circuit in which two half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switches and the low-side switches in the two half-bridge circuits are individually connected to two terminals of the DC motor to drive the DC motor, wherein one half-bridge circuit in the first circuit also serves as one half-bridge circuit in the second circuit.

2. An actuator comprising: an upper and lower leveling drive unit that includes one of a three-phase motor and a DC motor and changes the vertical direction of a light emitting section that emits light to the outside of a vehicle; a left and right leveling drive unit that includes the other of the three-phase motor and the DC motor and changes the left and right direction of the light emitting section; a first circuit in which three half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in the three half-bridge circuits are individually connected to three terminals of the three-phase motor to drive the three-phase motor; and a second circuit in which two half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in the two half-bridge circuits are individually connected to two terminals of the DC motor to drive the DC motor, wherein one half-bridge circuit in the first circuit also serves as one half-bridge circuit in the second circuit.

3. The actuator according to claim 2, characterized in that when the DC motor is driven with the high-side switch ON and the low-side switch OFF in the half-bridge circuits included in the first circuit and the second circuit, and the high-side switch OFF and the low-side switch ON in the half-bridge circuits not included in the first circuit, the high-side switch in at least one of the half-bridge circuits not included in the second circuit is turned ON, and the low-side switches in each of the half-bridge circuits not included in the second circuit are turned OFF.

4. A vehicle lighting device comprising: a light emitting unit that emits light to the outside of the vehicle; an up-down leveling drive unit that includes one of a three-phase motor and a DC motor and changes the vertical direction of the light emitting unit; a left-right leveling drive unit that includes the other of the three-phase motor and the DC motor and changes the left-right direction of the light emitting unit; a first circuit in which three half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in the three half-bridge circuits are individually connected to three terminals of the three-phase motor to drive the three-phase motor; and a second circuit in which two half-bridge circuits, each including a high-side switch and a low-side switch connected in series with each other, are connected in parallel with each other, and the electrical circuits between the high-side switch and the low-side switch in the two half-bridge circuits are individually connected to two terminals of the DC motor to drive the DC motor, wherein one half-bridge circuit in the first circuit also serves as one half-bridge circuit in the second circuit.

5. When the DC motor is driven with the high-side switch on and the low-side switch off in the half-bridge circuits included in the first circuit and the second circuit, and the high-side switch off and the low-side switch on in the half-bridge circuits not included in the first circuit, the high-side switch in at least one of the half-bridge circuits not included in the second circuit is turned on, and the low-side switches in each of the half-bridge circuits not included in the second circuit are turned off, as described in claim 4.

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