JP4730326B2 - Motor driver and valve timing adjusting device - Google Patents

Description

  The present invention relates to a motor driver and a valve timing adjusting device including the motor driver.

2. Description of the Related Art Conventionally, in the field of a valve timing adjusting device that adjusts the valve timing of an internal combustion engine by rotation of an electric motor as disclosed in Patent Document 1, for example, a motor driver that energizes and drives an electric motor using a power supply voltage is used. It is used. One type of such motor driver is to protect the motor driver by turning off the energization to the electric motor (hereinafter referred to as “motor energization”) when the power supply voltage falls below a threshold value. Patent Document 2 discloses this.
JP 2006-37837 A JP 2004-229410 A

  By the way, when the motor energization is turned off when the power supply voltage falls below the threshold, it is necessary to return the motor energization to the on state in response to the return of the power supply voltage. Therefore, the inventor has conducted intensive research on a technique for turning on the motor power when the power supply voltage once lower than the threshold exceeds the threshold. As a result of the inventor's research, when the voltage drop generated in the signal line becomes large due to the length of the signal line for supplying the power supply voltage from the external power source to the motor driver, the following problem occurs. Was found to occur.

  The problem is that in the on state of motor energization, a voltage obtained by subtracting the voltage drop from the power supply voltage from the external power supply is applied to the motor driver, but when the applied voltage falls below the threshold, The voltage drop disappears as the motor energization is turned off. As a result, the power supply voltage of the external power supply is directly applied to the motor driver, so that the applied voltage exceeds the threshold value and the motor energization is turned on. Then, the voltage drop occurs again and the motor energization is turned off, and thereafter, the motor energization is repeatedly turned on and off according to the disappearance / generation of the voltage drop, that is, the chattering state. Such energization chattering is not desirable because it causes failure and lowers durability rather than protecting the motor driver.

  The present invention has been made in view of the problems described above, and an object thereof is to provide a highly durable motor driver and a valve timing adjusting device including the motor driver.

According to the first aspect of the present invention, there is provided a filter circuit that filters an external power supply voltage and outputs an internal power supply voltage, an energization circuit that realizes motor energization by applying the internal power supply voltage, and an external power supply voltage or an internal power supply voltage. An energization off means for turning off the motor energization by the energization circuit on condition that the current is below the threshold, and an energization on means for turning on the motor energization by the energization circuit on condition that the external power supply voltage or the internal power supply voltage exceeds the threshold. In the motor driver, the energization on means for prohibiting the energization of the motor by the energization circuit until the predetermined on-side set time elapses after the external power supply voltage or the internal power supply voltage exceeds the threshold , the external power supply voltage If the internal power supply voltage exceeds the threshold before the ON side set time elapses, the internal power Until the and between the internal power supply voltage to the voltage exceeds the threshold value passes the on-side set time after exceeding a threshold value, prohibits an energizing by the energizing circuit.

According to the invention described in this claim 1, the voltage drop (hereinafter to a motor current is turned off the power source voltage on condition that the external supply voltage falls below the threshold value, it had been simply "voltage drop" in the column of solutions ) Disappears, even if the external power supply voltage exceeds the threshold value, turning on the motor energization is prohibited until the on-side set time elapses from that time. According to this, since it is possible to avoid a situation where the motor energization is turned on immediately after the external power supply voltage exceeds the threshold value and the voltage drop occurs again, the motor energization is repeatedly turned on / off according to the disappearance / occurrence of the voltage drop. That is, energization chattering can be suppressed. Therefore, it is possible to prevent the motor driver from being damaged due to energization chattering and to enhance its durability.
In the configuration in which the output internal power supply voltage is applied to the energization circuit from the filter circuit that filters the external power supply voltage, it is desirable to turn on / off the motor energization according to the behavior of each of the power supply voltages. Therefore, by prohibiting motor energization until the on-side set time elapses after the external or internal power supply voltage exceeds the threshold, suppression of energization chattering corresponding to each behavior of these power supply voltages individually The effect can be demonstrated.
Furthermore, in the configuration in which the output internal power supply voltage is applied from the filter circuit that filters the external power supply voltage to the energizing circuit, the external power supply voltage and the internal power supply voltage change according to the time constant of the filter circuit when they change in conjunction with each other. Thus, the change speed of the internal power supply voltage becomes slower than the change speed of the external power supply voltage. Therefore, according to the first aspect of the present invention, when the internal power supply voltage exceeds the threshold value until the ON side set time elapses after the external power supply voltage exceeds the threshold value, the external power supply voltage exceeds the threshold value. The energization of the motor by the energization circuit is prohibited until the internal power supply voltage exceeds the threshold and until the on-side set time elapses after the internal power supply voltage exceeds the threshold. According to this, although there is a change in conjunction with each other, it is possible to exhibit the effect of suppressing energization chattering by appropriately corresponding to both external and internal power supply voltages having different speeds of change.

According to the invention described in claim 2, energization on means, by an external power supply voltage is above the threshold at the time the external power supply voltage is turned on the side set time has exceeded the threshold value has elapsed, the motor energization by energization circuit When the on-side set time elapses, the power supply voltage is below the threshold value, so that the motor energization by the energization circuit is kept off. According to this, even if the external power supply voltage chatters once and exceeds the threshold value, even if it falls below the threshold value before the ON side set time elapses, the motor energization is held off and the chattering is performed. Can be suppressed. On the other hand, at the normal time when the external power supply voltage exceeds the threshold value until the on-side set time elapses, the motor energization is turned on after the elapse of time and can be reliably restored.

According to the invention described in claim 3 , the energization off means prohibits the energization circuit from turning off the motor energization until a predetermined off-side set time elapses after the external power supply voltage falls below the threshold value. Thus, after the motor current is turned on the voltage drop generated from higher than external power supply voltage is the threshold value after the on-side setting time, as an external power supply voltage drops below the threshold value, elapsed off side setting time from the below Until this is done, turning off the motor energization is prohibited. According to this, since it is possible to avoid a situation where the motor energization is turned off and the voltage drop disappears immediately after the external power supply voltage falls below the threshold value, the effect of suppressing energization chattering is enhanced.
In the configuration where the output internal power supply voltage is applied from the filter circuit that filters the external power supply voltage to the energizing circuit, the external power supply voltage may be momentarily interrupted. Can be suppressed accordingly. Therefore, by prohibiting the motor from being turned off until the off-side set time has elapsed after the external power supply voltage, which has a high possibility of instantaneous interruption among the external and internal power supply voltages, falls below the threshold, The effect of suppressing chattering can be enhanced.

According to the invention of claim 4, de-energization means, by an external power supply voltage is below the threshold value at the time the external power supply voltage is off-side setting time from below the threshold has elapsed, the motor energization by energization circuit When the off-side set time elapses, the external power supply voltage exceeds the threshold value, and the motor energization by the energization circuit is kept on. According to this, even if the external power supply voltage is momentarily interrupted and once falls below the threshold value and exceeds the threshold value before the OFF side set time elapses, the motor energization is kept on and the chattering is performed. Can be suppressed. On the other hand, at the normal time when the external power supply voltage falls below the threshold until the off-side set time elapses, the motor driver can be turned off after the elapse of time to reliably protect the motor driver.

In the configuration in which the output internal power supply voltage is applied from the filter circuit that filters the external power supply voltage to the energization circuit, as described above, the possibility of instantaneous interruption of the internal power supply voltage is low. Therefore, according to the fifth aspect of the present invention, the energization off means turns off the motor energization by the energization circuit when the internal power supply voltage falls below the threshold value. According to this, when the current consumption of the electric motor increases, for example, when the internal power supply voltage falls below the threshold value, the motor energization can be immediately turned off. Motor failure can be suppressed.

In the configuration in which the output internal power supply voltage is applied to the energization circuit from the filter circuit that filters the external power supply voltage, when the external and internal power supply voltages change in conjunction with each other as described above, the change rate of the internal power supply voltage is external. It becomes slower than the change speed of the power supply voltage. Further, in such a configuration, the external power supply voltage is more reliable than the internal power supply voltage as the power supply voltage serving as a reference for turning on / off the motor. Therefore, according to the sixth aspect of the present invention, the off-side set time is set within a falling period from when the internal power supply voltage starts decreasing until it falls below the threshold value. According to this, the internal power supply voltage that changes in conjunction with the external power supply voltage can be made lower than the threshold value after the motor energization is turned off due to the lapse of the off-side set time from being below the threshold value of the external power supply voltage. Therefore, when the external and internal power supply voltages change in conjunction with each other, not only can the motor power be turned off in a timely manner based on the highly reliable external power supply voltage, but also the internal power supply voltage can be lowered after the power is turned off. It is possible to realize the energized off state.

The invention according to claim 7 is an electric motor, and the motor driver according to any one of claims 1 to 6 which drives the electric motor by energization using a power supply voltage, and the internal combustion engine by rotation of the electric motor. And an adjusting mechanism for adjusting the valve timing. According to the invention described in claim 7 , the motor driver according to any one of claims 1 to 6 exhibits an effect of suppressing energization chattering to prevent a failure of the motor driver. Therefore, it is possible to adjust the valve timing stably over a long period of time.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 2 to 6 show a valve timing adjusting device 1 according to an embodiment of the present invention. The valve timing adjusting device 1 is mounted on a vehicle and adjusts the valve timing of an intake valve or an exhaust valve of an internal combustion engine.

(Basic configuration of electric unit)
First, the basic configuration of the electric unit 10 of the valve timing adjusting device 1 shown in FIG. 2 will be described. The electric unit 10 includes an electric motor 12 and a motor driver 60.

  The electric motor 12 is a brushless motor, and includes a motor case 13, a motor shaft 14, and a motor coil 15 (see FIG. 3). The motor case 13 is fixed to the internal combustion engine via a stay. The motor case 13 supports the motor shaft 14 so as to be rotatable forward and backward, and fixes each motor coil 15. In the electric motor 12, when a rotating magnetic field in the forward direction that is clockwise in FIG. 4 is formed by energizing each motor coil 15, the motor shaft 14 is rotationally driven in the forward direction. On the other hand, when a rotating magnetic field in the reverse direction, which is counterclockwise in FIG. 4, is formed by energizing each motor coil 15, the motor shaft 14 is driven to rotate in the reverse direction.

  As shown in FIG. 2, the motor driver 60 is accommodated in the motor case 13. The motor driver 60 is electrically connected to each motor coil 15 of the electric motor 12 as shown in FIG. The motor driver 60 rotationally drives the motor shaft 14 by energizing each motor coil 15.

(Basic configuration of adjustment mechanism)
Next, the basic configuration of the adjusting mechanism 20 of the valve timing adjusting device 1 shown in FIG. 2 will be described. The adjusting mechanism 20 includes a driving side rotating body 22, a driven side rotating body 24, a differential gear mechanism section 30, and a link mechanism section 50.

  The drive-side rotator 22 is a timing sprocket around which a timing chain is wound between the crankshaft of the internal combustion engine. When the output torque of the crankshaft is input to the drive-side rotator 22, the drive-side rotator 22 rotates in the clockwise direction of FIG. 5 while maintaining a relative phase with the crankshaft in conjunction with the crankshaft. The driven-side rotating body 24 is coaxially fixed to the cam shaft 2 of the internal combustion engine, and rotates in the clockwise direction in FIG.

  As shown in FIGS. 2 and 4, the differential gear mechanism 30 includes a sun gear 31, a planet carrier 32, a planet gear 33, a transmission rotating body 34, and the like. The sun gear 31 formed of an internal gear is screwed coaxially to the drive side rotator 22 and rotates integrally with the drive side rotator 22 by transmission of the output torque of the crankshaft. The planet carrier 32 is connected to the motor shaft 14 through a joint 35 and rotates integrally with the motor shaft 14 by transmission of rotational torque from the motor shaft 14. The planetary carrier 32 forms an eccentric portion 36 by a cylindrical outer peripheral surface portion that is eccentric with respect to the driving side rotating body 22. The planetary gear 33 made of an external gear is fitted to the eccentric portion 36 via the bearing 37 and is arranged eccentrically with respect to the sun gear 31. The planetary gear 33 meshes with the sun gear 31 from the inner peripheral side, and performs a planetary motion according to the relative rotation of the motor shaft 14 with respect to the drive side rotating body 22. The transmission rotating body 34 is concentrically fitted to the outer peripheral side of the driven side rotating body 24. The transmission rotating body 34 is provided with a plurality of engagement holes 38 arranged at equal intervals in the rotation direction. The planetary gear 33 is provided with a plurality of engagement protrusions 39 protruding into the engagement holes 38. Then, when each of the engagement protrusions 39 engages with the engagement hole 38, the rotation motion of the planetary gear 33 is extracted and converted into the rotation motion of the transmission rotating body 34.

  As shown in FIGS. 2, 5, and 6, the link mechanism unit 50 includes links 52 and 53, a guide unit 54, a movable body 56, and the like. In FIGS. 5 and 6, hatching representing a cross section is omitted for easy understanding of the description. The first link 52 is connected to the drive-side rotator 22 by a pair. The second link 53 is connected to the driven-side rotating body 24 by a turning pair and is connected to the first link 52 by a turning pair via the movable body 56. The guide portion 54 is formed by a portion including an end surface on the opposite side to the planetary gear 33 in the transmission rotating body 34. A guide groove 58 in which the movable body 56 is slidably fitted is formed in the guide portion 54. The guide groove 58 is formed in a spiral groove shape whose distance from the rotation center of the guide portion 54 changes in the longitudinal direction.

  In the adjustment mechanism 20 having such a configuration, when the motor shaft 14 does not rotate relative to the drive-side rotator 22, the planetary gear 33 rotates integrally with the drive-side rotator 22 and the transmission rotator 34 without planetary motion. To do. As a result, the movable body 56 is not guided in the guide groove 58, and the relative positional relationship between the links 52 and 53 does not change, so that the relative phase between the driving side rotating body 22 and the driven side rotating body 24, and hence the valve timing, is increased. Retained. When the motor shaft 14 is driven to rotate in the forward rotation direction with respect to the drive-side rotator 22, the transmission rotator 34 is rotated counterclockwise in FIG. Relative rotation. As a result, the movable body 56 is guided in the guide groove 58 and the relative positional relationship between the links 52 and 53 changes, whereby the driven-side rotator 24 is relative to the drive-side rotator 22 in the clockwise direction in FIG. Since it rotates, the valve timing is advanced. When the motor shaft 14 is driven to rotate relative to the drive side rotator 22 in the reverse rotation direction, the valve timing is retarded according to the principle opposite to that for the relative rotation drive in the forward rotation direction.

(Characteristic configuration of motor driver)
Next, a characteristic configuration of the motor driver 60 according to the present embodiment will be described. As shown in FIG. 3, the motor driver 60 includes an external terminal 62, a filter circuit 70, and an inverter unit 80.

  The external terminal 62 is electrically connected via a signal line 66 to a battery 64 as an external power source disposed outside the motor driver 60 in the vehicle. With this connection, the external power supply voltage Vo supplied from the battery 64 through the signal line 66 is applied to the external terminal 62. Here, an energization circuit 82 of the electric motor 12 is electrically connected to the external terminal 62 via a filter circuit 70 as described later. With this connection, when energization to the electric motor 12 is turned on, a voltage drop ΔVd is generated in the signal line 66. Therefore, the voltage drop ΔVd is subtracted from the voltage Vb of the battery 64 (hereinafter referred to as “battery voltage”) Vb. Is applied to the external terminal 62 as the external power supply voltage Vo. On the other hand, when the electric motor 12 is turned off, the voltage drop ΔVd disappears, so that the battery voltage Vb is directly applied to the external terminal 62 as the external power supply voltage Vo.

  The filter circuit 70 is formed by combining an inductor 72 and capacitors 74 and 76. Both ends of the inductor 72 are electrically connected between the external terminal 62 and the inverter unit 80. One end of the first capacitor 74 is electrically connected to one end of the inductor 72 and the external terminal 62, and the other end of the first capacitor 74 is grounded. One end of the second capacitor 76 is electrically connected to the other end of the inductor 72 and the inverter unit 80, and the other end of the second capacitor 76 is grounded. With the above configuration, a π-type filter circuit 70 is formed on the upstream side of the inverter unit 80, and the circuit 70 filters the external power supply voltage Vo applied to the external terminal 62 to perform the internal power supply voltage Vi. Is output to the inverter unit 80 side. Therefore, in the motor driver 60, a situation in which fluctuating noise due to an instantaneous interruption of the external power supply voltage Vo is propagated to the inverter unit 80 side and malfunctions are suppressed is suppressed.

  The inverter unit 80 includes an energization circuit 82, a switching circuit 84, and the like. The energization circuit 82 is a bridge circuit and is electrically connected to the filter circuit 70. With this connection, the internal power supply voltage Vi output from the filter circuit 70 is applied to the energization circuit 82, and the battery 64 side of fluctuation noise caused by the consumption current of the electric motor 12 is applied by the filter circuit 70. Propagation to is suppressed.

  The energization circuit 82 includes a plurality of arms 86u, 86v, 86w that are electrically connected to the corresponding motor coils 15, respectively. A switching element 88 is provided on each of the upper and lower sides of the arms 86u, 86v, and 86w that sandwich the connection point with the motor coil 15. Each switching element 88 is, for example, a MOS type field effect transistor, and is turned on / off by a drive signal.

  The switching circuit 84 includes a memory 89 as a control IC for the energization circuit 82, and is electrically connected to the filter circuit 70. By this connection, the internal power supply voltage Vi output from the filter circuit 70 is also applied to the switching circuit 84, and the internal power supply voltage Vi can be detected by the switching circuit 84. Further, the switching circuit 84 can detect the external power supply voltage Vo by being electrically connected to the external terminal 62. Further, the switching circuit 84 is electrically connected to the gates of the switching elements 88, and switches the elements 88 on and off by changing the voltage level of the drive signal applied to the switching elements 88. As a result, the energization state of each motor coil 15 changes according to the on / off state of each switching element 88, and the electric motor 12 rotates or stops.

  The switching circuit 84 according to the present embodiment turns on / off the energization of each motor coil 15 of the electric motor 12 (hereinafter referred to as “motor energization” again) based on the detected external power supply voltage Vo and internal power supply voltage Vi. Control off.

(Motor energization on / off control)
Next, the flow of on / off control of motor energization by the switching circuit 84 will be described with reference to FIGS. The on / off control starts when the ignition switch of the vehicle is turned on and ends when the ignition switch is turned off.

  As shown in FIG. 7, in step S101 of on / off control, it is determined whether or not the external power supply voltage Vo is lower than a threshold value Vth.

Here, the threshold value Vth is an upper limit value of the voltage value that needs to be turned off in order to protect the inverter unit 80. The threshold value Vth is set in advance so as to satisfy the following threshold value condition. Is remembered.
Threshold condition: smaller than the value obtained by subtracting the predicted maximum value of the voltage drop ΔVd from the normal value of the battery voltage Vb (see FIGS. 1 and 9).
For example, when the normal value of the battery voltage Vb is 12V and the predicted maximum value of the voltage drop ΔVd is 2 to 3V, the threshold Vth is set to about 7.7V.

  If an affirmative determination is made in step S101, the process proceeds to step S102 to start the timer T, and in the subsequent step S103, the motor energization is kept on. Thereafter, in step S104, it is determined whether or not a predetermined off-side set time Toff has elapsed since the start of the timer T. As a result, if a negative determination is made, the process returns to step S103, so that the motor energization is prohibited until the off-side set time Toff elapses.

Here, the off-side set time Toff is preset and stored in the memory 89 so as to satisfy the following off-time conditions 1 and 2.
Off-time condition 1: More than the instantaneous voltage interruption time Tm in which it is not necessary to turn off the motor in order to protect the inverter unit 80 (see FIG. 11)
Off-time condition 2: within the fall period Ti from when the internal power supply voltage Vi starts to fall to below the threshold value Vth (see FIG. 10)
For example, when the instantaneous interruption time Tm is 100 μs and the falling period Ti is 176 μs, the off-side set time Toff is about 130 ± 20 μs.

  If an affirmative determination is made in step S104, that is, if the off-side set time Toff has elapsed from the start of the timer T, the process proceeds to step S105, where the timer T is stopped and reset. Thereafter, in step S106, it is determined again whether or not the external power supply voltage Vo is lower than the threshold value Vth. As a result, if a negative determination is made, the process proceeds to step S107, the motor energization is kept on, and then the process returns to step S101. Therefore, when the external power supply voltage Vo that once falls below the threshold value Vth returns above the threshold value Vth within the off-side set time Toff due to a momentary interruption of the battery voltage Vb, the motor energization is turned off and the inverter unit 80 is turned off. Since it is no longer necessary to protect the motor, the energization of the motor is continued. On the other hand, if an affirmative determination is made in step S106, the process proceeds to step S108 to switch the motor energization from on to off to protect the inverter unit 80.

  Up to this point, the subsequent steps when an affirmative determination is made in step S101 have been described, but the following steps will be described below when a negative determination is made in step S101.

  If a negative determination is made in step S101, the process proceeds to step S109 to determine whether or not the internal power supply voltage Vi is below the same threshold value Vth as in step S101. As a result, if a negative determination is made, it is not necessary to turn off the motor energization this time, and the process returns to step S101. On the other hand, if an affirmative determination is made, the process proceeds to step S108 to switch the motor energization from on to off to protect the inverter unit 80.

  As described above, in this embodiment, when the external power supply voltage Vo falls below the threshold value Vth, the motor energization is turned off after the off-side set time Toff elapses. However, when the internal power supply voltage Vi falls below the threshold value Vth. The motor energization is turned off almost simultaneously.

  Now, after the motor energization is switched off in step S108, the process proceeds to step S110 shown in FIG. 8, and it is determined whether or not the external power supply voltage Vo exceeds the same threshold value Vth as in step S101. As a result, if an affirmative determination is made, the process proceeds to step S111 to start the timer T, and in the subsequent step S112, the motor energization is held off. Thereafter, in step S113, it is determined whether or not the internal power supply voltage Vi exceeds the same threshold value Vth as in step S110. If a negative determination is made, the process proceeds to step S114, and a predetermined time from the start of the timer T is determined. It is determined whether the on-side set time Ton has elapsed. As a result, if a negative determination is made, the process returns to step S112. Therefore, unless the internal power supply voltage Vi exceeds the threshold value Vth, the motor energization is prohibited until the on-side set time Ton elapses. .

Here, the on-side set time Ton is preset and stored in the memory 89 so as to satisfy the next on-time condition.
On-time condition: More than half of the maximum value of the chattering cycle predicted for each power supply voltage Vo, Vi and battery voltage Vb For example, when the half-value of the predicted maximum value of the chattering cycle is 160 ms, the on-side set time Ton is 200 It is set to about ± 10 ms.

  When an affirmative determination is made in step S114, that is, when the on-side set time Ton has elapsed from the start of the timer T, the process proceeds to step S115, where the timer T is stopped and reset. Thereafter, in step S116, it is determined again whether or not the external power supply voltage Vo exceeds the threshold value Vth. As a result, if a negative determination is made, the process proceeds to step S117, the motor energization is kept off, and then the process returns to step S110. Therefore, when the external power supply voltage Vo once exceeds the threshold value Vth returns below the threshold value Vth within the on-side set time Ton due to chattering of the external power supply voltage Vo or the battery voltage Vb, the inverter is turned on when the motor energization is turned on. Since the unit 80 cannot be protected, the motor energization is kept off. On the other hand, if an affirmative determination is made in step S116, the process proceeds to step S118, the motor energization is switched from OFF to ON, and then the process returns to step S101.

  The case where the internal power supply voltage Vi does not exceed the threshold value Vth within the on-side set time Ton from above the threshold value Vth of the external power supply voltage Vo is as described above, but in the opposite case, the process proceeds to step S119. , Reset and restart timer T. In the subsequent step S120, the motor energization is kept off, and in the subsequent step S121, it is determined whether or not the same on-side set time Ton as in step S114 has elapsed since the restart of the timer T. As a result, if a negative determination is made, the process returns to step S120. Therefore, after the external power supply voltage Vo exceeds the threshold value Vth, until the internal power supply voltage Vi exceeds the threshold value Vth and until the on-side set time Ton elapses from the increase of the internal power supply voltage Vi, It is prohibited to turn on the motor.

  If an affirmative determination is made in step S121, that is, if the on-side set time Ton has elapsed from the restart of the timer T, the routine proceeds to step S122, where the timer T is stopped and reset. Thereafter, in step S123, it is determined again whether or not the internal power supply voltage Vi exceeds the threshold value Vth. As a result, if a negative determination is made, the process proceeds to step S124, the motor energization is kept off, and then the process returns to step S110. Therefore, if the internal power supply voltage Vi once exceeds the threshold value Vth and returns below the threshold value Vth within the on-side set time Ton due to chattering of the internal power supply voltage Vi or the battery voltage Vb, the inverter is turned on when the motor energization is turned on. Since the unit 80 cannot be protected, the motor energization is kept off. On the other hand, if an affirmative determination is made in step S123, the process proceeds to step S125, the motor energization is switched from OFF to ON, and then the process returns to step S101.

  Up to this point, the following steps have been described in the case where an affirmative determination is made in step S110. Next, the subsequent steps in the case where a negative determination is made in step S110 will be described.

  If a negative determination is made in step S110, the process proceeds to step S126, and it is determined whether or not the internal power supply voltage Vi exceeds the same threshold value Vth as in step S110. As a result, if a negative determination is made, it is not necessary to turn on the motor energization this time, and the process returns to step S110. On the other hand, if a positive determination is made, the process proceeds to step S127 to start the timer T, and then proceeds to step S120. Therefore, in this case, the motor energization is prohibited from turning on until the on-side set time Ton elapses from the start of the timer T. After the elapse of time, the motor energization is performed according to the relationship between the internal power supply voltage Vi and the threshold value Vth. It is held off or switched on.

(Switching circuit operation)
Next, operation examples 1 to 5 of the switching circuit 84 realized by the on / off control of FIGS.

(Operation example 1)
FIG. 1 shows that the internal power supply voltage Vi is maintained, for example, by the electric motor 12 generating power almost simultaneously with a decrease in the battery voltage Vb or an abnormal voltage drop of the signal line 66, so that only the external power supply voltage Vo is the threshold value Vth. Operation Example 1 is shown in the case of returning after falling below.

  Specifically, in the first operation example, when the external power supply voltage Vo decreases and falls below the threshold value Vth, turning off the motor energization is prohibited until the off-side set time Toff elapses. When the off-side set time Toff elapses, the motor energization is turned off and the voltage drop ΔVd of the signal line 66 disappears. However, in Operation Example 1, the motor energization is turned off because the external power supply voltage Vo does not exceed the threshold value Vth. Maintained in a state.

  Thereafter, when the external power supply voltage Vo rises and exceeds the threshold value Vth, the turning-on of the motor is prohibited until the on-side set time Ton elapses. When the on-side set time Ton elapses, the motor energization is turned on and a voltage drop ΔVd is generated in the signal line 66. However, in Operation Example 1, the motor energization is on because the external power supply voltage Vo does not fall below the threshold value Vth. Maintained in a state.

  As described above, according to this embodiment, immediately after the external power supply voltage Vo falls below the threshold value Vth, the motor energization is prohibited, and immediately after the power supply voltage Vo exceeds the threshold value Vth, the motor energization is prohibited. Thus, energization chattering can be suppressed.

(Operation example 2)
FIG. 9 shows an operation example 2 in a case where the current consumption of the electric motor 12 rapidly increases and only the internal power supply voltage Vi returns after falling below the threshold value Vth.

  Specifically, in the operation example 2, first, when the internal power supply voltage Vi decreases and falls below the threshold value Vth, the motor energization is immediately turned off without waiting for the off-side set time Toff. Therefore, the inverter unit 80 and the electric motor 12 Is protected.

  Furthermore, in the operation example 2, the voltage drop ΔVd disappears by turning off the motor energization, and the internal power supply voltage Vi once rises and exceeds the threshold value Vth. However, due to the on-time condition, the voltage Vi drops again and falls below the threshold value Vth until the on-side set time Ton elapses from exceeding the threshold value Vth of the internal power supply voltage Vi. Thus, the energization off state is maintained.

  Thereafter, when the internal power supply voltage Vi rises and exceeds the threshold value Vth, the motor energization is prohibited from being turned on until the on-side set time Ton elapses. When the on-side set time Ton elapses, the motor energization is turned on and a voltage drop ΔVd is generated on the signal line 66. However, in Operation Example 2, the motor energization is on because the internal power supply voltage Vi does not fall below the threshold value Vth. Maintained in a state.

  As described above, according to the present embodiment, when the internal power supply voltage Vi is chattered due to the disappearance of the voltage drop ΔVd, and also immediately after the power supply voltage Vi exceeds the threshold value Vth, turning on the motor is prohibited. Can be suppressed.

(Operation example 3)
FIG. 10 shows that the threshold voltage Vth is linked with the external and internal power supply voltages Vo and Vi due to the decrease in the battery voltage Vb or the abnormal voltage drop of the signal line 66 or in addition to the sudden increase in the consumption current of the electric motor 12. Operation Example 3 in the case of returning after falling below is shown.

  In the present embodiment, due to the action of the filter circuit 70, the falling speed of the internal power supply voltage Vi is slower than the falling speed of the external power supply voltage Vo. Therefore, in the operation example 3, first, when the external power supply voltage Vo decreases and falls below the threshold value Vth, the motor energization is prohibited.

  In the present embodiment, the internal power supply voltage Vi does not fall below the threshold value Vth within the off-side set time Toff due to the off-time condition 2. Therefore, in the operation example 3, when the off-side set time Toff elapses, the voltage drop ΔVd disappears by turning off the motor energization. However, the internal power supply voltage Vi has the threshold value Vth according to the same principle as in the operation example 2. Therefore, the motor energization is maintained in the off state in a manner corresponding to the lower direction.

Further, in the present embodiment, due to the function of the filter circuit 70, the rising speed of the internal power supply voltage Vi is slower than the rising speed of the external power supply voltage Vo. Thus in operation example 3, after the on-the motor energization is prohibited by exceeding the threshold value Vth rises external power supply voltage Vo, an internal power supply voltage Vi from exceeding the external power supply voltage Vo on side set time in Ton When raised to above the threshold value Vth, to the further on-side setting time from exceeding Ton of the internal power supply voltage Vi has elapsed, on the motor current continues to be prohibited. When the on-side set time Ton elapses after the internal power supply voltage Vi exceeds the threshold value Vth, a voltage drop ΔVd is generated by turning on the motor energization. Since voltage Vi does not fall below threshold value Vth, motor energization is maintained in the on state.

  Thus, according to the present embodiment, immediately after the external power supply voltage Vo falls below the threshold value Vth, the motor energization is prohibited from being turned off, and even when the internal power supply voltage Vi is chattered due to the disappearance of the voltage drop ΔVd. , Vi is prohibited from being turned on immediately after exceeding Vi threshold value Vth. Therefore, energization chattering can be suppressed.

(Operation example 4)
FIG. 11 shows an operation example 4 in the case where only the external power supply voltage Vo falls below the threshold value Vth and then recovers due to a momentary interruption of the battery voltage Vb.

  In the present embodiment, due to the function of the filter circuit 70, the internal power supply voltage Vi hardly changes even if the battery voltage Vb is momentarily interrupted. Therefore, in the operation example 4, first, when the external power supply voltage Vo falls below the threshold value Vth in response to the instantaneous interruption of the battery voltage Vb, the motor energization is prohibited from being turned off. However, the external power supply voltage Vo is It returns until the OFF side set time Toff elapses from the lower limit. As a result, the external power supply voltage Vo exceeds the threshold value Vth at the elapse of the off-side set time Toff, so that the motor energization remains on. Therefore, since the motor energization is maintained in the on state regardless of the instantaneous interruption of the battery voltage Vb, the energization chattering can be suppressed.

  As described above, according to the present embodiment, the energization chattering can be sufficiently and reliably suppressed, so that the inverter unit 80 can be prevented from being broken and its durability can be enhanced. As a result, it is possible to realize stable valve timing adjustment over a long period of time.

  In the embodiment described so far, the switching circuit 84 that executes the steps S101 to S109 of the on / off control corresponds to the “energization off means” recited in the claims, and the steps S110 to S110 of the on / off control. The switching circuit 84 that executes S127 corresponds to the “energization on means” recited in the claims.

(Other embodiments)
Although one embodiment of the present invention has been described above, the present invention is not construed as being limited to the embodiment, and can be applied to various embodiments without departing from the scope of the invention. it can.

  For example, when the motor energization is turned off based on the internal power supply voltage Vi, the off-side set time Toff elapses after the internal power supply voltage Vi falls below the threshold value Vth in accordance with the case based on the external power supply voltage Vo. The energization off may be realized.

  As the electric motor 12, an electric motor having various configurations can be adopted even if it is other than the brushless motor described above. Further, as the filter circuit 70, filter circuits having various configurations can be employed as long as the effects of the present invention can be obtained, even if other than the above-described π-type filter circuit. Further, as the adjusting mechanism 20, various configurations can be used as long as the valve timing of the internal combustion engine can be adjusted by the rotation of the electric motor, even if the adjusting mechanism 20 is not provided with the differential gear mechanism 30 and the link mechanism 50 described above. This mechanism can be adopted.

  The present invention can be applied to various motor drivers for energizing and driving an electric motor using a power supply voltage, in addition to the motor driver for the valve timing adjusting device.

It is a schematic diagram which shows the operation example 1 of the switching circuit of the motor driver by one Embodiment of this invention. FIG. 6 is a configuration diagram illustrating a valve timing adjusting device according to an embodiment of the present invention, which corresponds to a cross-sectional view taken along line II-II in FIG. 5. It is a block diagram which shows the electric unit of FIG. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is the VI-VI sectional view taken on the line of FIG. It is a flowchart which shows the on / off control flow of motor energization which the switching circuit of the motor driver by one Embodiment of this invention implement | achieves. FIG. 8 is a flowchart showing a motor energization on / off control flow realized by the motor driver switching circuit according to the embodiment of the present invention, which is continued from VIII in FIG. 7. It is a schematic diagram which shows the operation example 2 of the switching circuit of the motor driver by one Embodiment of this invention. It is a schematic diagram which shows the operation example 3 of the switching circuit of the motor driver by one Embodiment of this invention. It is a schematic diagram which shows the operation example 4 of the switching circuit of the motor driver by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve timing adjustment device, 2 cam, 10 Electric unit, 12 Electric motor, 14 Motor shaft, 15 Motor coil, 20 Adjustment mechanism, 30 Differential gear mechanism part, 50 Link mechanism part, 60 Motor driver, 62 External terminal, 64 Battery, 66 Signal line, 70 Filter circuit, 72 Inductor, 74 First capacitor, 76 Second capacitor, 80 Inverter part, 82 Energizing circuit, 84 Switching circuit (Energizing off means, Energizing on means), 86u, 86v, 86w Arm , 88 switching element, 89 memory, T timer, Toff off side set time, Ton on side set time, Ti falling period, Tm instantaneous interruption time, Tc chattering cycle, Vb battery voltage, Vo external power supply voltage, Vi internal power supply voltage, Vth threshold

Claims (7)

A filter circuit that filters the external power supply voltage and outputs the internal power supply voltage; an energization circuit that applies current to the electric motor by applying the internal power supply voltage; and the external power supply voltage or the internal power supply voltage falls below a threshold value it on condition, and de-energization means for turning off the current supply by the conducting circuit, wherein the external power supply voltage or condition the internal power supply voltage may exceed the threshold value, and a current-on means for turning on the power by the energizing circuit In the motor driver provided,
The energization on means for prohibiting energization by the energization circuit until a predetermined on-side set time elapses after the external power supply voltage or the internal power supply voltage exceeds the threshold , the external power supply voltage exceeds the threshold. When the internal power supply voltage exceeds the threshold value until the on-side set time elapses after the power supply voltage exceeds the threshold value, the internal power supply voltage exceeds the threshold value and the internal power supply voltage exceeds the threshold value. The motor driver , wherein energization by the energization circuit is prohibited during a period from when the internal power supply voltage exceeds the threshold until the on-side set time elapses . Said energization-on means, by said external power supply voltage at the time when said external power supply voltage has passed the on-side set time has exceeded the threshold value exceeds the threshold value to turn on the power by the energizing circuit, 2. The motor driver according to claim 1 , wherein energization by the energization circuit is held off when the external power supply voltage is lower than the threshold at the time when the on-side set time elapses. The de-energization means according to claim 1 or 2, characterized in that the external power supply voltage to prohibit off energization by the energizing circuit from below the threshold until the elapse of the predetermined off-side setting time Motor driver. The de-energization means, by said external power supply voltage is the external power supply voltage at the time of the OFF-side set time has elapsed since below the threshold value is below the threshold value, and deenergized by the conducting circuit, 4. The motor driver according to claim 3 , wherein energization by the energization circuit is kept on when the external power supply voltage exceeds the threshold at the time when the off-side set time elapses. 5. The motor driver according to claim 3 , wherein the energization off unit turns off the energization by the energization circuit when the internal power supply voltage falls below the threshold. 6. The motor driver according to claim 5 , wherein the off-side set time is set within a falling period from when the internal power supply voltage starts to drop to below the threshold value. An electric motor;
The motor driver according to any one of claims 1 to 6 , wherein the electric motor is energized and driven using a power supply voltage.
An adjustment mechanism for adjusting a valve timing of the internal combustion engine by rotation of the electric motor.

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