JP2008215274A - Valve timing adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve timing adjusting device preventing failures. <P>SOLUTION: A valve timing adjusting device provided with an electric motor including a motor shaft and generating controlled torque on the motor shaft by electricity supply, an electricity supply control part executing advancing control of electricity supply to the electric motor, and a phase adjusting mechanism adjusting relative phase between a crank shaft and a cam shaft by rotationally driving the camshaft according to controlled torque given by the motor shaft, prohibits the electricity supply control circuit part from executing advancing control of electricity supply to the electric motor when actual rotation direction Dr of the motor shaft changes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a valve timing adjusting device for an internal combustion engine that adjusts the valve timing of at least one of an intake valve and an exhaust valve whose camshaft opens and closes by torque transmission from a crankshaft.

  Conventionally, the control torque generated on the motor shaft of the electric motor is applied to the phase adjusting mechanism, and the cam shaft is rotationally driven in accordance with the control torque, whereby the relative phase between the crank shaft and the cam shaft (hereinafter, There is known a valve timing adjusting device (hereinafter referred to as “electric valve timing adjusting device”) that adjusts “engine phase”). As this type of electric valve timing adjusting device, Patent Document 1 discloses an apparatus that generates an appropriate control torque in accordance with an operation state of an internal combustion engine by controlling energization to an electric motor. Yes.

By the way, in an electric motor such as an embedded magnet type brushless motor in which a permanent magnet is embedded in a motor shaft, the actual motor energization may be delayed with respect to the energization control timing. In general, in the field of electric motors, energization advance control is widely used as a method for eliminating such energization delay and increasing motor efficiency (see, for example, Patent Document 2).
JP 2005-9480 A JP 2004-180399 A

  So far, the present inventor has conducted intensive research on a technique for applying advance angle control to energization of an electric motor in an electric valve timing adjusting device. However, as a result of the inventor's research, it has been found that if the advance angle control is performed when the actual rotation direction of the motor shaft changes, the following problem occurs.

  When the actual rotation direction of the motor shaft changes, the actual rotation speed of the motor shaft once becomes zero. In the phase adjustment mechanism, the cam shaft on which the cam torque acts is rotated according to the control torque from the motor shaft by the reaction force from the valve to be opened / closed, so that at the moment when the actual rotational speed of the motor shaft becomes zero, FIG. When the advance angle control is performed as shown in FIG. 4, there is a possibility that a control torque necessary for rotationally driving the camshaft against the cam torque cannot be obtained sufficiently (see, for example, the black circle in FIG. 24). As a result, the motor shaft is locked, and a large current flows through an energization control circuit unit (for example, a drive circuit) that controls energization of the electric motor, which may cause a failure.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a valve timing adjusting device that prevents failure.

  The invention according to claim 1 is an electric valve timing adjustment device for an internal combustion engine that adjusts the valve timing of at least one of an intake valve and an exhaust valve whose camshaft opens and closes by torque transmission from a crankshaft, and includes a motor An electric motor that has a shaft and generates a control torque on the motor shaft by energization, an energization control circuit unit that controls the advance of energization to the electric motor, and a cam shaft that rotates according to the control torque applied from the motor shaft Thus, the energization control circuit unit prohibits advance angle control when the actual rotation direction of the motor shaft changes.

  According to the first aspect of the present invention, since the advance angle control with respect to the energization of the electric motor is prohibited when the actual rotation direction of the motor shaft changes, the motor shaft advances at the moment when the actual rotation speed of the motor shaft becomes zero. Angle control is not performed. Thereby, at the moment when the actual rotational speed becomes zero, the control torque necessary for the phase adjusting mechanism to rotationally drive the cam shaft against the cam torque can be secured in the motor shaft. Locking can be avoided. Therefore, it is possible to prevent a situation in which a large current flows through the energization control circuit unit of the electric motor and a failure occurs.

  According to the invention described in claim 2, the electric motor is an embedded magnet type brushless motor in which a permanent magnet is embedded in the motor shaft. In such an embedded magnet type brushless motor, since the actual energization tends to be delayed with respect to the energization control timing due to the generation of the reluctance torque, the advance angle control is effective. On the other hand, in the configuration in which the cam shaft on which the cam torque acts is driven to rotate by the phase adjustment mechanism according to the control torque from the motor shaft, the advance angle control at the moment when the actual rotation speed of the motor shaft becomes zero is a failure of the energization control circuit section. It becomes a factor causing problems. However, as described above, by prohibiting the advance angle control when the actual rotation direction of the motor shaft changes, it is caused by the advance angle control while utilizing the effectiveness of the advance angle control for the embedded magnet type brushless motor. The failure problem can also be solved.

  In order to change the actual rotation direction of the motor shaft, it is necessary to make the target rotation direction of the motor shaft different from the actual rotation direction. Therefore, when the target rotation direction and the actual rotation direction are different, the probability that the actual rotation direction is changing is high. Therefore, according to the third aspect of the invention, the energization control circuit unit prohibits the advance angle control due to the difference between the target rotation direction of the motor shaft and the actual rotation direction, and therefore when the actual rotation direction changes. Can surely prohibit the advance angle control.

  After the actual rotation direction of the motor shaft changes, the actual rotation direction matches the target rotation direction of the motor shaft. Therefore, if the directions coincide with each other after the difference between the target rotation direction and the actual rotation direction, there is a high probability that the actual rotation direction has been changed. Therefore, according to the fourth aspect of the present invention, the energization control circuit unit matches the target rotation direction with the actual rotation direction after prohibiting the advance angle control due to the difference between the target rotation direction and the actual rotation direction of the motor shaft. By doing so, the advance angle control is restored. According to this, after the change in the actual rotation direction, which eliminates the necessity of prohibiting the advance angle control, the advance angle control can be reliably restored and the effect of eliminating the energization delay can be enjoyed.

  When the actual rotational direction of the motor shaft changes, the actual rotational speed of the motor shaft temporarily decreases to zero. Therefore, when the actual rotational speed decreases below the threshold value, there is a high probability that the actual rotational direction is changing. Therefore, according to the fifth aspect of the present invention, the energization control circuit unit prohibits the advance angle control by reducing the actual rotational speed of the motor shaft to be equal to or less than the threshold value, so that it is reliable when the actual rotational direction changes. The advance angle control can be prohibited.

  When the actual rotational direction of the motor shaft changes, the actual rotational speed of the motor shaft once decreases to zero and then increases. Therefore, when the actual number of rotations rises after the threshold value or less and exceeds the threshold value, the probability that the actual rotation direction has changed is high. Therefore, according to the invention described in claim 6, the energization control circuit unit increases the actual rotational speed after prohibiting the advance angle control due to the actual rotational speed of the motor shaft being equal to or lower than the threshold, and exceeds the threshold. To return the advance angle control. According to this, after the change in the actual rotation direction, which eliminates the necessity of prohibiting the advance angle control, the advance angle control can be reliably restored and the effect of eliminating the energization delay can be enjoyed.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment.

(First embodiment)
FIG. 2 shows the electric valve timing adjusting device 1 according to the first embodiment of the present invention. The electric valve timing adjusting device 1 is mounted on a vehicle and is installed in a transmission system that transmits engine torque from a crankshaft (not shown) of an internal combustion engine to a camshaft 2.

(Basic configuration)
First, the basic configuration of the electric valve timing adjusting device 1 will be described. The electric valve timing adjusting device 1 is a combination of the electric motor 4, the energization control circuit unit 6 and the phase adjusting mechanism 8, and adjusts the valve timing determined by the engine phase between the crankshaft and the camshaft 2. In the present embodiment, the camshaft 2 opens and closes the intake valve of the internal combustion engine, and the electric valve timing adjusting device 1 adjusts the valve timing of the intake valve.

  As shown in FIGS. 2 and 3, the electric motor 4 is an embedded magnet type brushless motor. Specifically, the electric motor 4 includes a housing 10, a bearing 12, a motor shaft 14, a permanent magnet 18, and a motor stator 16. The housing 10 is fixed to a fixed joint 9 of an internal combustion engine such as a chain case. Two bearings 12 and a motor stator 16 are accommodated and fixed in the housing 10. Each bearing 12 supports a shaft main body 14a of the motor shaft 14 so as to be rotatable forward and backward. In the motor shaft 14, a plurality of permanent magnets 18 are embedded in the rotor portion 14 b protruding from the shaft main body 14 a toward the outer peripheral side in a form aligned at equal intervals in the rotation direction. The permanent magnets 18 adjacent to each other in the rotation direction form opposite magnetic poles on the outer peripheral wall side of the rotor portion 14b. The motor stator 16 is disposed concentrically on the outer peripheral side of the rotor portion 14b, and has a core 16a and a coil 16b. The core 16 a is formed by stacking iron pieces, and a plurality of cores 16 a are provided at equal intervals in the rotation direction of the motor shaft 14. A coil 16b is wound around each core 16a.

  The energization control circuit unit 6 is electrically connected to each coil 16b of the electric motor 4, and controls energization to these coils 16b in accordance with the operating condition of the internal combustion engine. Under this energization control, the electric motor 4 forms a rotating magnetic field acting on each permanent magnet 18 by exciting each coil 16b, thereby generating a control torque in a direction corresponding to the formed magnetic field in the rotor portion 14b. The motor shaft 14 is rotated. Here, in the present embodiment, with respect to the motor shaft 14, the clockwise direction and the counterclockwise direction in FIG. 3 are defined as the forward rotation direction and the reverse rotation direction, respectively.

  Next, the phase adjustment mechanism 8 shown in FIG. 2 will be described. The phase adjustment mechanism 8 includes a driving side rotating body 22, a driven side rotating body 24, a planetary gear unit 30, and a link unit 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 rotor 24 is coaxially fixed to the camshaft 2 of the internal combustion engine, and rotates together with the camshaft 2 in the clockwise direction in FIG. As described above, in the present embodiment, the forward rotation direction of the motor shaft 14 is set to the same direction as the rotation direction of the internal combustion engine, and the reverse rotation direction of the motor shaft 14 is set to the opposite direction to the rotation direction of the internal combustion engine.

  2 and 4, the planetary gear unit 30 includes a sun gear 31, a planet carrier 32, a planetary 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 shaft main body 14a of the motor shaft 14 via a joint 35, and rotates according to the control torque transmitted 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. 5 and 6, the link unit 50 includes links 52 and 53, a guide portion 54 and a movable body 56. In FIGS. 5 and 6, hatching representing a cross section is omitted. 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. As shown in FIGS. 2 and 6, 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.

  The phase adjusting mechanism 8 having the above-described structure is a control torque applied from the motor shaft 14 to the cam shaft 2 in which the cam torque caused by the reaction force from the intake valve acts alternately on the retard side and the advance side as shown in FIG. The engine phase is adjusted by rotationally driving in accordance with the engine.

  Specifically, when the motor shaft 14 does not rotate relative to the drive-side rotator 22 due to control torque maintenance or the like, the planetary gear 33 rotates together with the drive-side rotator 22 and the transmission rotator 34 without planetary motion. . 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 motor-side shaft 14 and the camshaft 2 are rotated together to drive-side rotating body 22 And the engine phase that determines the valve timing are maintained. On the other hand, when the motor shaft 14 rotates relative to the drive side rotator 22 in the forward direction due to an increase in the control torque in the forward direction, the transmission rotator 34 is driven by the planetary motion of the planetary gear 33. Relative rotation in the counterclockwise direction of FIG. 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 is changed, so that the camshaft 2 together with the driven-side rotating body 24 and the driving-side rotating body 22 are shown in FIG. Since the engine is driven to rotate in the clockwise direction, the engine phase is advanced. On the other hand, when the motor shaft 14 rotates relative to the drive side rotor 22 in the reverse rotation direction due to an increase in the control torque in the reverse rotation direction, etc., it is driven by the principle opposite to the relative rotation in the normal rotation direction. The camshaft 2 is driven to rotate in the counterclockwise direction in FIG.

(Electric motor)
Hereinafter, a characteristic configuration of the electric motor 4 will be described. As shown in FIGS. 2 and 8, the electric motor 4 further includes three rotation angle sensors SU, SV, and SW. Each rotation angle sensor SU, SV, SW is composed of, for example, a Hall element or the like, and is positioned at a predetermined interval in the rotation direction of the motor shaft 14. The rotation angle sensors SU, SV, SW each output a detection signal representing the actual rotation position θ of the motor shaft 14 by sensing the magnetic field formed by the magnetic poles of the sensor magnet 20 mounted on the motor shaft 14.

  Specifically, the rotation angle sensors SU, SV, SW are turned on when the north pole of the sensor magnet 20 is located within each sensing range, and the voltage level of the detection signal is high as shown in FIG. (H). Further, the rotation angle sensors SU, SV, SW are turned off when the S pole of the sensor magnet 20 is located within each sensing range, and the voltage level of the detection signal is set to low (L) as shown in FIG. . Therefore, the detection signal of each rotation angle sensor SU, SV, SW is a signal whose voltage level increases or decreases according to the actual rotation position θ of the motor shaft 14.

(Energization control circuit)
Hereinafter, a characteristic configuration of the energization control circuit unit 6 will be described. As shown in FIG. 2, the energization control circuit unit 6 includes a control circuit 60 and a drive circuit 70. In the present embodiment, the control circuit 60 is arranged outside the electric motor 4 and the drive circuit 70 is arranged inside the electric motor 4, but both the circuits 60 and 70 are arranged outside or inside the electric motor 4. You may do it.

  The control circuit 60 is mainly composed of a microcomputer, and is electrically connected to the drive circuit 70 as shown in FIG. The control circuit 60 has a function of controlling energization to the electric motor 4 as well as a function of controlling the internal combustion engine.

  The control circuit 60 calculates the actual valve timing of the engine phase based on the actual rotation direction Dr and the actual rotation speed Sr of the electric motor 4 given from the drive circuit 70, and also sets the target valve based on the operation status of the internal combustion engine. Calculate timing. Further, the control circuit 60 sets the target rotation direction Dt and the target rotation speed St of the electric motor 4 based on the calculated phase difference between the actual valve timing and the target valve timing, and sets the setting results as the drive circuit 70. Output to.

  The drive circuit 70 is provided with a signal generation block 72 and an energization block 74. In the present embodiment, each of the blocks 72 and 74 is configured by hardware using dedicated electric circuit elements.

  The signal generation block 72 is electrically connected to the rotation angle sensors SU, SV, SW, the control circuit 60 and the energization block 74 of the electric motor 4. The signal generation block 72 calculates the actual rotation direction Dr and the actual rotation speed Sr of the electric motor 4 based on the detection signals of the rotation angle sensors SU, SV, SW representing the actual rotation position θ of the motor shaft 14, respectively. Is output to the control circuit 60 and the energization block 74.

  As shown in FIG. 9, the energization block 74 has an inverter unit 76 and a drive unit 78. The inverter unit 76 formed of a bridge circuit includes upper switching elements FU, FV, FW and lower switching elements GU, GV, GW. The upper switching elements FU, FV, and FW and the lower switching elements GU, GV, and GW are electrically connected with the same reference numerals, and each coil 16b of the electric motor 4 is star-connected between these connection points. Has been. Each of the switching elements FU, FV, FW, GU, GV, and GW has a characteristic of being turned on by a drive signal having a high voltage level and turned off by a drive signal having a low voltage level.

  The drive unit 78 includes a control IC, and is electrically connected to the switching elements FU, FV, FW, GU, GV, and GW of the control circuit 60, the signal generation block 72, and the inverter unit 76. Based on the target rotational direction Dt and the target rotational speed St given from the control circuit 60 and the actual rotational direction Dr and the actual rotational speed Sr given from the signal generation block 72, the drive unit 78 is connected to each switching element FU, FV, FW, GU, GV, and GW are driven on and off. As a result, motor energization is realized and control torque is generated in the motor shaft 14.

  Here, as shown in FIGS. 10 and 11, the drive unit 78 of the present embodiment has patterns i to vi of drive signal voltage levels to be applied to the switching elements FU, FV, FW, GU, GV, and GW (hereinafter, “ The control torque is adjusted by controlling the “energization pattern”. 10 and 11, in each of the energization patterns i to vi, when the voltage level of the drive signal is high, L is when the voltage level of the drive signal is low, and the voltage level of the drive signal is pulse width modulated. The case where it is made to represent is represented as P.

  Specifically, when both the target and actual rotation directions Dt and Dr are normal rotation directions, the drive unit 78 switches the motor shaft 14 during normal rotation by switching the energization patterns i to vi shown in FIG. The control torque in the forward rotation direction acting on is adjusted. When both the target and actual rotation directions Dt and Dr are in the reverse rotation direction, the drive unit 78 switches the energization patterns i to vi shown in FIG. 11 in the reverse direction to change the reverse rotation direction acting on the motor shaft 14 during the reverse rotation. Adjust the control torque. When the target and actual rotation directions Dt and Dr are the normal rotation direction and the reverse rotation direction, respectively, the drive unit 78 switches the energization patterns i to vi shown in FIG. Adjust the control torque to apply the brake. When the target and actual rotation directions Dt and Dr are the reverse and normal rotation directions, respectively, the drive unit 78 switches the energization patterns i to vi shown in FIG. Adjust the control torque to apply the brake. In any of these cases, the drive unit 78 sets the on-duty ratio of the pulse width modulation in each of the energization patterns i to vi based on the rotational speed difference between the target rotational speed St and the actual rotational speed Sr. It is.

  As shown in FIG. 12, the drive unit 78 of the present embodiment further controls the advance of the switching timing of the energization patterns i to vi when the target rotation direction Dt and the actual rotation direction Dr match, while the target rotation direction The advance angle control is prohibited when Dt and the actual rotation direction Dr are different.

  Specifically, when both the target and actual rotation directions Dt and Dr are normal rotation directions, the drive unit 78 indicates the forward switching timing of the energization patterns i to vi shown in FIG. Of the detection signals of the rotation angle sensors SU, SV, and SW, the voltage level of the signal associated in advance is advanced with respect to the switching timing (hereinafter referred to as “related signal switching timing”). Similarly, when both the target and actual rotation directions Dt and Dr are in the reverse rotation direction, the drive unit 78 indicates the reverse direction switching timing of the energization patterns i to vi shown in FIG. 11 as shown in FIG. , SV, SW are advanced with respect to the related signal switching timing. In any of these cases, the drive unit 78 sets the advance amount Ta of the switching timing of the energization patterns i to vi to a predetermined ratio with respect to the time difference Td between the related signal switching timings of the rotation angle sensors SU, SV, SW. Therefore, it is set according to the actual rotational speed Sr.

  On the other hand, when the target and actual rotation directions Dt and Dr are the forward rotation direction and the reverse rotation direction, respectively, the driving unit 78 sets the reverse direction switching timing of the energization patterns i to vi shown in FIG. The timing is matched with the related signal switching timing of the sensors SU, SV, and SW. Similarly, when the target and actual rotation directions Dt and Dr are the reverse rotation direction and the normal rotation direction, respectively, the drive unit 78 rotates the forward switching timing of the energization patterns i to vi shown in FIG. 11 as shown in FIG. The timing is matched with the related signal switching timing of the angle sensors SU, SV, SW. Therefore, in any of these cases, the advance angle of the switching timing of the energization patterns i to vi is prohibited.

  As described above, in the first embodiment, for example, when the target rotation direction Dt changes from the normal rotation direction to the reverse rotation direction during the normal rotation of the motor shaft 14 as shown in FIG. 1, the direction Dt is different from the actual rotation direction Dr. Therefore, the advance angle control of the switching timing of the energization patterns i to vi is prohibited as shown in FIG. At this time, since the switching mode of the energization patterns i to vi is the forward direction switching in FIG. 11, the motor shaft 14 during normal rotation is braked in the reverse direction, and the actual rotational speed Sr decreases. As a result, the actual rotational speed Sr once becomes zero, but since the advance angle control is prohibited at this moment of zero, a control torque (for example, torque represented by a white circle in FIG. 17) that can counter the cam torque is generated. The motor shaft 14 starts reverse rotation. That is, since the actual rotation direction Dr changes in the reverse rotation direction and coincides with the target rotation direction Dt, the advance angle control of the switching timing of the energization patterns i to vi returns as shown in FIG.

  As described above, according to the first embodiment, when the actual rotational direction Dr changes, the advance angle control is prohibited from before the change and the lock of the motor shaft 14 is avoided. It is possible to prevent a situation where a current flows and breaks down. Further, if the prohibition of the advance angle control is not required, the advance angle control is appropriately performed immediately after that, so that the energization delay caused by the reluctance torque can be eliminated.

(Second embodiment)
As shown in FIG. 18, the second embodiment of the present invention is a modification of the first embodiment. The drive unit 78 of the second embodiment performs advance control of the switching timing of the energization patterns i to vi when the actual rotational speed Sr of the motor shaft 14 exceeds a predetermined threshold Sth, while the actual rotational speed Sr is equal to or less than the threshold Sth. In such a case, the advance angle control is prohibited. Here, the threshold value Sth is set to a value near zero rotation, and is set in a range where the influence of the advance angle control in the apparatus 1 is sufficiently small. As a result, the region where the actual rotational speed Sr becomes a value near zero rotation substantially overlaps the region where the target rotational direction Dt and the actual rotational direction Dr are different, and advance angle control can be prohibited in this region. .

  Specifically, when the actual rotational speed Sr exceeds the threshold value Sth and the directions Dt and Dr are both in the normal rotation direction or both the reverse rotation directions, the driving unit 78 performs the energization patterns i to vi shown in FIG. The direction or reverse direction switching timing is advanced with respect to the related signal switching timing of the rotation angle sensors SU, SV, SW as shown in FIG. 13 or FIG. Similarly, when the actual rotational speed Sr exceeds the threshold value Sth and the directions Dt and Dr are one of the forward rotation direction and the reverse rotation direction and the other, the drive unit 78 has the energization patterns i to vi shown in FIG. The reverse or forward switching timing is advanced with respect to the related signal switching timing of the rotation angle sensors SU, SV, SW as shown in FIG. In any of these cases, the drive unit 78 sets the advance amount Ta of the switching timing of the energization patterns i to vi in the same manner as in the first embodiment.

  When the actual rotational speed Sr is equal to or less than the threshold value Sth and the directions Dt and Dr are both forward rotation directions or both reverse rotation directions, the driving unit 78 performs forward or reverse switching of the energization patterns i to vi shown in FIG. The timing is matched with the related signal switching timing of the rotation angle sensors SU, SV, SW as shown in FIG. Similarly, when the actual rotational speed Sr is equal to or less than the threshold value Sth and the directions Dt and Dr are one of the forward rotation direction and the reverse rotation direction, the drive unit 78 reverses the energization patterns i to vi shown in FIG. 10 or FIG. As shown in FIG. 15 or FIG. 16, the timing for switching the direction or the forward direction is matched with the related signal switching timing of the rotation angle sensors SU, SV, SW. Therefore, in any of these cases, the advance angle of the switching timing of the energization patterns i to vi is prohibited.

  As described above, in the second embodiment, for example, when the target rotation direction Dt changes from the normal rotation direction to the reverse rotation direction during the normal rotation of the motor shaft 14 as shown in FIG. 23, the switching pattern of the energization patterns i to vi is the forward direction of FIG. Since switching is performed, the motor shaft 14 during normal rotation is braked in the reverse direction, and the actual rotational speed Sr decreases. At this time, while the actual rotational speed Sr exceeds the threshold value Sth, the switching timing of the energization patterns i to vi is controlled to advance as shown in FIG. 20, and when the actual rotational speed Sr decreases to the threshold value Sth or less, the advance angle Control is prohibited as shown in FIG. As a result, since the actual rotational speed Sr once becomes zero in the energization control prohibition state, a control torque that can counteract the cam torque is generated, the motor shaft 14 starts reverse rotation, and the actual rotational speed Sr increases. Become. Therefore, as long as the actual rotational speed Sr is equal to or less than the threshold value Sth after the actual rotational direction Dr is changed in the reverse direction, the advance control of the switching timing of the energization patterns i to vi is kept in a prohibited state as shown in FIG. When the actual rotational speed Sr exceeds the threshold value Sth, the advance angle control returns as shown in FIG.

  Thus, also in the second embodiment, when the actual rotation direction Dr changes, the advance angle control is prohibited before and after the change and the lock of the motor shaft 14 is avoided, so that the inverter unit 76 is avoided. It is possible to prevent a situation in which a large current flows through the terminal and breaks down. In addition, after the prohibition of the advance angle control is no longer necessary, the advance angle control can be appropriately performed to eliminate the energization delay caused by the reluctance torque.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described so far, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments within the scope not departing from the gist thereof. it can.

  For example, the electric motor 4 may be other than a buried magnet type brushless motor as long as it is a motor that requires advance control of energization.

  Further, the energization control circuit unit 6 may have a configuration other than the combination of the above-described two circuits 60 and 70 as long as the energization of the electric motor 4 can be advanced. Here, for example, both functions of the circuits 60 and 70 may be performed by a single electric circuit. In the drive circuit 70, some of the functions may be realized by a microcomputer.

  Furthermore, the phase adjustment mechanism 8 has a configuration other than the configuration including the planetary gear unit 30 described above as long as the engine phase can be adjusted by rotationally driving the camshaft 2 according to the control torque generated by the electric motor 4. It may be. Specifically, a sun gear that meshes with the planetary gear is provided on both of the two rotating bodies that rotate in conjunction with the crankshaft and the camshaft, and the engine phase is changed by the planetary motion of the planetary gear. The phase adjustment mechanism 8 or the like having the configuration may be used.

  In addition to the above-described device for adjusting the valve timing of the intake valve, the present invention is suitably applied to a device for adjusting the valve timing of the exhaust valve and a device for adjusting the valve timing of both the intake valve and the exhaust valve. be able to.

It is a schematic diagram for demonstrating the characteristic action | operation of 1st embodiment of this invention. It is a block diagram which shows the electric valve timing adjustment apparatus by 1st embodiment of this invention, Comprising: It corresponds to the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line 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 schematic diagram for demonstrating the cam torque which acts on a cam shaft in 1st embodiment of this invention. It is a block diagram which shows the electricity supply control circuit part of FIG. It is a block diagram which shows the detailed structure of the electricity supply block of FIG. It is a schematic diagram for demonstrating the electricity supply control by 1st and 2nd embodiment of this invention. It is a schematic diagram for demonstrating the electricity supply control by 1st and 2nd embodiment of this invention. It is a mimetic diagram for explaining energization control by a first embodiment of the present invention. It is a schematic diagram for demonstrating the electricity supply control by 1st and 2nd embodiment of this invention. It is a schematic diagram for demonstrating the electricity supply control by 1st and 2nd embodiment of this invention. It is a schematic diagram for demonstrating the electricity supply control by 1st and 2nd embodiment of this invention. It is a schematic diagram for demonstrating the electricity supply control by 1st and 2nd embodiment of this invention. It is a schematic diagram for demonstrating the characteristic action | operation of 1st embodiment of this invention. It is a mimetic diagram for explaining energization control by a second embodiment of the present invention. It is a mimetic diagram for explaining energization control by a second embodiment of the present invention. It is a mimetic diagram for explaining energization control by a second embodiment of the present invention. It is a mimetic diagram for explaining energization control by a second embodiment of the present invention. It is a mimetic diagram for explaining energization control by a second embodiment of the present invention. It is a schematic diagram for demonstrating the characteristic action | operation of 2nd embodiment of this invention. It is a schematic diagram for demonstrating the subject solved by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric valve timing adjustment apparatus, 2 Cam shaft, 4 Electric motor, 6 Current supply control circuit part, 8 Phase adjustment mechanism, 14 Motor shaft, 14a Shaft main body, 14b Rotor part, 16 Motor stator, 18 Permanent magnet, 20 Sensor magnet, 60 control circuit, 70 drive circuit, 72 signal generation block, 74 energization block, 76 inverter unit, 78 drive unit, Dr actual rotation direction, Dt target rotation direction, Sr actual rotation number, St target rotation number, Sth threshold, SU, SV, SW rotation angle sensor, FU, FV, FW Upper switching element, GU, GV, GW Lower switching element, i, ii, iii, iv, v, vi Energization pattern, Ta lead angle, Td Time difference

Claims (6)

A valve timing adjustment device for an internal combustion engine that adjusts the valve timing of at least one of an intake valve and an exhaust valve whose camshaft opens and closes by torque transmission from a crankshaft,
An electric motor having a motor shaft and generating a control torque on the motor shaft by energization;
An energization control circuit unit for controlling the advance of energization to the electric motor;
A phase adjustment mechanism that adjusts a relative phase between the crankshaft and the camshaft by rotationally driving the camshaft according to the control torque applied from the motor shaft;
With
The valve timing adjustment device, wherein the energization control circuit unit prohibits the advance angle control when the actual rotation direction of the motor shaft changes.   2. The valve timing adjusting device according to claim 1, wherein the electric motor is an embedded magnet type brushless motor in which a permanent magnet is embedded in the motor shaft.   3. The valve timing adjustment device according to claim 1, wherein the energization control circuit unit prohibits the advance angle control when a target rotation direction and an actual rotation direction of the motor shaft are different. 4.   4. The valve timing according to claim 3, wherein the energization control circuit unit restores the advance angle control when the target rotation direction and the actual rotation direction coincide with each other after the advance angle control is prohibited. Adjustment device.   3. The valve timing adjustment device according to claim 1, wherein the energization control circuit unit prohibits the advance angle control when an actual rotational speed of the motor shaft decreases to a threshold value or less.   6. The valve timing adjustment according to claim 5, wherein the energization control circuit unit restores the advance angle control when the actual rotation speed increases and exceeds the threshold value after the advance angle control is prohibited. apparatus.

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