JP4678393B2 - Valve drive control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve body drive controller by which breakage of a tooth in a gear constituting a power transmission mechanism of a drive unit can be appropriately detected. <P>SOLUTION: An EGR control valve 15 is equipped with: a butterfly valve 17; a valve shaft 18 which turns together with the butterfly valve 17; a reduction gear mechanism 19 which transmits power to the valve shaft 18; an electric motor 20 which drives the butterfly valve 17 via the reduction gear mechanism 19; and a turning angle sensor 21 which detects an opening degree of the butterfly valve 17. An ECU 16 feedback-controls the opening degree of the butterfly valve 17, based on a detection signal of the turning angle sensor 21, eventually controlling an opening degree of the EGR control valve 15. Besides, the ECU 16 monitors the opening degree of the butterfly valve 17 and then detects a situation, in which a change in the opening degree is reciprocated, as the breakage of the tooth in the gear constituting the reduction gear mechanism 19. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a drive control device for a valve body that detects breakage of gear teeth constituting a power transmission mechanism of a drive device.

2. Description of the Related Art An exhaust gas recirculation device for recirculating a part of exhaust gas from an internal combustion engine is well known (see, for example, Patent Document 1). Such an exhaust gas recirculation device includes an exhaust gas recirculation passage for recirculating exhaust gas, a butterfly valve provided in the exhaust gas recirculation passage, a spring that biases the butterfly valve toward the valve closing side, and the spring And a driving device that drives the butterfly valve against the urging force. The drive device also includes an electric motor and a gear reduction mechanism, and the power of the electric motor is transmitted to the butterfly valve by the gear reduction mechanism.
JP 2003-314377 A

  Here, in the case where the butterfly valve is driven to the valve opening side against the biasing force of the spring by the electric motor, if the tooth portion of the gear constituting the gear reduction mechanism is damaged, the gear having the damaged tooth portion and the gear Of the gears that mesh with the gears, one gear (drive gear) on the electric motor side is rotated to the valve opening side of the butterfly valve by the driving force of the electric motor, and the other gear (driven gear) is the butterfly valve by the biasing force of the spring. Rotates to the valve closing side. As described above, when the gear tooth portion is damaged, the controllability of the opening degree of the butterfly valve is lowered. In addition, the tooth portions of the drive gear and the driven gear collide with force, and the tooth portions of the drive gear or the driven gear may be further damaged. Such a problem is not limited to the exhaust gas recirculation device drive device, but the driven gear is biased in a predetermined direction by a biasing means such as a spring, and the power source such as a motor resists the biasing force of the biasing means. This is applied to a drive device that drives a drive gear, and occurs in a drive control device that controls opening and closing of a valve body by the drive device.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is a main object of the present invention to provide a drive control device for a valve body that suitably detects breakage of gear teeth constituting a power transmission mechanism of a drive device. It is the purpose.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  According to the first aspect of the present invention, a drive gear, a driven gear meshing with the drive gear, a biasing means for biasing the driven gear in a predetermined rotational direction, and the drive gear against the biasing force of the biasing means. It is applied to a drive device provided with a motive power source that drives.

  Here, when the valve body is driven against the urging force of the urging means, if the tooth portion of the drive gear or the driven gear is damaged (if the tooth portion is missing), the change in the opening degree of the valve body is reciprocated. Indicates. Specifically, when the tooth portion of the driving gear or the driven gear is damaged, the driven gear rotates in the direction opposite to the driving direction by the power source by the biasing force of the biasing means. And if a drive gear and a driven gear mesh | engage in the tooth | gear part which is not damaged, a driven gear will rotate in the drive direction by a power source. Thereby, the change of the opening degree of a valve body shows a reciprocation.

  The inventor pays attention to this point, and in the invention according to claim 1, the opening degree of the valve element is monitored, and the state in which the change in the opening degree indicates reciprocation is determined by the tooth portion of the drive gear or the driven gear. Detected as broken.

  In the invention according to claim 2, the state in which the change in the opening degree of the valve body indicates reciprocation with a width corresponding to n teeth (n is a positive integer) is the tooth portion of the drive gear or the driven gear. Detect as damage. When n tooth portions continuous in the rotation direction of the tooth portions of the drive gear or the driven gear are damaged, the reciprocal width becomes a size corresponding to n tooth portions of the drive gear or the driven gear. Therefore, by detecting the state in which the change in the opening degree of the valve body indicates reciprocation with a width corresponding to n teeth as described above, the detection accuracy is detected by detecting the damage to the teeth of the drive gear or the driven gear. Can be increased.

  Incidentally, in addition to the case where the tooth portion of the drive gear or the driven gear is damaged, it is conceivable to control the opening degree of the valve body so that the change in the opening degree of the valve body indicates reciprocation, for example.

  Therefore, in the invention according to claim 3, the breakage of the tooth portion of the drive gear or the driven gear is detected based on the reciprocation time of the opening degree of the valve body. If the change in the opening of the valve element indicates reciprocation as a result of damage to the teeth of the drive gear or driven gear, the reciprocation time is the number of gear teeth damaged, the driving force of the power source, the urging force of the urging means, etc. Determined by. On the other hand, when the opening degree is reciprocated as the opening degree control of the valve body, the reciprocation time is determined only by the driving force of the power source. Thus, it is thought that the reciprocation time of the opening degree of a valve body differs between the case where the tooth | gear part of a drive gear or a driven gear is damaged, and other cases. Therefore, the detection error can be suppressed by detecting the breakage of the tooth portion of the drive gear or the driven gear based on the reciprocation time of the opening degree of the valve body as described above.

  In a fourth aspect of the invention, the state in which the reciprocation of the opening degree of the valve body is repeatedly detected is detected as a breakage of the tooth portion of the drive gear or the driven gear. When the drive gear or the driven gear is damaged and the valve body is continuously driven against the urging force of the urging means, the reciprocation of the opening degree of the valve body repeatedly occurs. For example, the reciprocation of the opening degree of the valve body occurs continuously (Claim 5), or the reciprocation of the opening degree of the valve body occurs periodically after a predetermined time (Claim 6). Therefore, it is possible to suppress the erroneous detection by detecting the state in which the reciprocation of the opening degree of the valve body is repeatedly generated as described above as the breakage of the tooth portion of the drive gear or the driven gear.

  By the way, when the tooth part of a drive gear or a driven gear is damaged, there exists a possibility that the tooth part of a drive gear or a driven gear may be damaged further as mentioned above. Therefore, in the invention according to the seventh aspect, when the breakage of the tooth portion of the drive gear or the driven gear is detected, a predetermined fail process is performed. Thereby, the further damage of the tooth | gear part of a drive gear and a driven gear can be suppressed.

  For example, as the fail process, the valve body may be maintained at a predetermined opening (for example, a fully closed opening) (Claim 8), or a warning is given that the tooth portion of the drive gear or the driven gear is damaged. (Claim 9). By maintaining the valve body at a predetermined opening, it is possible to avoid a collision between the tooth portion of the drive gear and the tooth portion of the driven gear, and to suppress further damage to the tooth portion of the drive gear or the driven gear. Further, warning that the tooth portion of the drive gear or the driven gear is damaged can suppress further damage to the tooth portion of the drive gear or the driven gear as a result of calling attention.

  In the invention described in claim 10, the fail process is performed according to the reciprocation of the opening degree of the valve body. Here, it is conceivable that the reciprocation mode (for example, reciprocation width, reciprocation time, reciprocation generation period) changes depending on the damage state of the tooth portions of the drive gear and the driven gear. Therefore, by carrying out the fail process according to the above-described reciprocation mode, it is possible to effectively suppress further damage to the tooth portions of the drive gear or the driven gear.

  The invention according to claim 11 controls the opening degree of the butterfly valve, which is provided in the flow path through which the exhaust or intake air of the internal combustion engine flows as a valve body and adjusts the flow rate of the intake or exhaust gas flowing through the flow path.

  Note that the functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.

  The present embodiment embodies the present invention as a drive control device that constitutes an exhaust gas recirculation device for an in-vehicle internal combustion engine. First, the configuration of the exhaust gas recirculation device according to the present embodiment will be described. An exhaust gas recirculation device 10 shown in FIG. 1 is connected to an exhaust passage 12 of an internal combustion engine 11 and a part of the exhaust gas flowing through the exhaust passage 12 is used as an exhaust gas recirculation gas (hereinafter referred to as “EGR gas”). An exhaust gas recirculation passage 14 for recirculation (recirculation) to the exhaust gas, and an exhaust gas recirculation amount control valve that is connected to the exhaust gas recirculation passage 14 and adjusts the recirculation amount of the EGR gas that circulates in the intake passage 13 of the internal combustion engine 11. (Hereinafter referred to as “EGR control valve”) 15 and an ECU 22 that controls each part of the engine system mainly composed of the internal combustion engine 11.

  The EGR actuator 15 includes a butterfly valve 17 provided in the exhaust gas recirculation passage 14, a valve shaft 18 that rotates together with the butterfly valve 17, a gear reduction mechanism 19 that transmits power to the valve shaft 18, and a gear reduction mechanism thereof. An electric motor 20 that drives the butterfly valve 17 via 19 and a rotation angle sensor 21 that detects the opening degree of the butterfly valve 17 are provided. In the EGR actuator 15, the butterfly valve 17 rotates to a fully open position in a predetermined direction (positive side) and to a predetermined position on the negative side with reference to the fully closed position. The electric motor 20 and the rotation angle sensor 21 are connected to the ECU 22.

  The ECU 22 is an electronic control unit mainly composed of a known microcomputer provided with a CPU, a memory and the like. In addition to the rotation angle sensor 21, the ECU 22 includes a crank angle sensor that outputs a pulse signal at every predetermined crank angle of the internal combustion engine 11 (for example, at a cycle of 30 ° CA), and an accelerator opening that outputs a signal correlated with the accelerator operation amount. A degree sensor is connected. The memory stores various programs and parameters. The CPU controls each part of the internal combustion engine 11 based on detection signals from sensors such as the rotation angle sensor 21, the crank angle sensor, and the accelerator opening sensor by executing a program stored in the memory. For example, the CPU controls the opening degree of the EGR actuator 15 in order to properly adjust the EGR gas circulation flow rate.

  A display device 23 is connected to the ECU 22. The display device 23 is constituted by a lamp or the like provided in an instrument panel in front of the driver's seat, and displays various states of the engine system.

  Next, the configuration of the EGR actuator 15 will be described in detail with reference to FIG. A tubular nozzle 30 forming a part of the exhaust gas recirculation passage 14 is held in the housing 16 of the EGR actuator 15, and a butterfly valve 17 is accommodated in the nozzle 30 so as to be freely opened and closed. . In addition, the valve shaft 18 of the butterfly valve 17 is rotatably supported by the housing 16. Specifically, the valve shaft 18 is supported by a bushing (bearing part) 32, an oil seal (seal material) 33, and a ball bearing (bearing part) 34.

  The axial end of the valve shaft 18 (the end on the butterfly valve 17 side) protrudes into the exhaust gas recirculation passage 14 through a shaft insertion hole 36 provided in the nozzle fitting portion 35 of the housing 16. The butterfly valve 17 is provided at the tip. On the other hand, at the rear end of the valve shaft 18 in the axial direction (end opposite to the butterfly valve 17), the configuration of the valve side gear 50, which is one of the components of the gear reduction mechanism 19, and the rotation angle sensor 21. A rotor 37, which is one of the elements, is provided.

  A coil spring 40 as an urging means is attached to the valve side gear 50. The coil spring 40 biases the butterfly valve 17 toward the fully closed position when the engine is stopped. Specifically, the coil spring 40 is a spiral spring in which a return spring 41 and a default spring 42 are integrated, and the springs 41 and 42 are wound in different directions. Further, a U-shaped hook portion that abuts against the valve full-close stopper member when the engine is stopped is provided at a coupling portion that couples the return spring 41 and the default spring 42.

  Here, the return spring 41 is a spring for biasing the butterfly valve 17 in a direction (negative side) to return from the fully open position to the fully closed position, and the default spring 42 is a position that passes the fully closed position to the negative side. It is a spring that urges the butterfly valve 17 in the direction of returning the butterfly valve 17 to the valve fully closed position (positive side). Note that the return spring 41 and the default spring 42 may be individual springs. Moreover, if the specification does not rotate the butterfly valve 17 to the negative side with respect to the fully closed opening degree, the return spring 41 may not be provided.

  The rotation angle sensor 21 as the opening degree detection means has a rotor 37, a permanent magnet 38 attached to the rotor 37, and a Hall IC 39 disposed to face the rear end portion of the valve shaft 18. The Hall IC 39 is an integrated circuit having a Hall element (magnetic detection element) and an amplifier circuit that amplifies the output. According to the rotation angle sensor 21, the direction of the magnetic field applied to the Hall IC 39 changes as the permanent magnet 38 rotates as the valve shaft 18 rotates. As a result, a detection signal corresponding to the opening degree of the butterfly valve 17 is output by the Hall IC 39. In place of the Hall element, a magnetoresistive element may be used as the magnetic detection element.

  The housing 16 houses an electric motor 20 as a power source. The electric motor 20 may be a brushless DC motor (direct current motor) or a brushed DC motor.

  Further, the housing 16 accommodates a gear constituting the gear reduction mechanism 19 in a rotatable manner. The gear reduction mechanism 19 reduces the rotational speed of the motor shaft 44 of the electric motor 20 to a predetermined reduction ratio, and transmits the driving force of the electric motor 20 to the valve shaft 18 of the butterfly valve 17. Mechanism. The gear reduction mechanism includes a pinion gear 46 fixed to the outer periphery of the motor shaft 44 of the electric motor 20, an intermediate reduction gear 47 that rotates in mesh with the pinion gear 46, and a valve that rotates in mesh with the intermediate reduction gear 47. And a side gear 50. The intermediate reduction gear 47 is rotatably fitted on the outer periphery of the holding shaft that forms the center of rotation. The intermediate reduction gear 47 is provided with a large diameter gear portion 48 that meshes with the pinion gear 46 and a small diameter gear portion 49 that meshes with the valve side gear 50.

  Next, the opening degree control of the butterfly valve 17 will be described. The ECU 22 calculates the actual opening of the butterfly valve 17 based on the detection signal of the rotation angle sensor 21, and feedback-controls the opening of the butterfly valve 17 based on the actual opening.

  Specifically, the rotational speed of the internal combustion engine 11 is calculated based on the pulse signal of the crank angle sensor, and the accelerator operation amount is calculated based on the detection signal of the accelerator opening sensor. Thereafter, a command value (hereinafter referred to as “command injection amount”) for the fuel injection valve of the internal combustion engine 11 is calculated based on the engine rotation speed and the accelerator operation amount, and the engine rotation speed and the command injection amount are used as parameters. With reference to the target opening map, a target value of the opening of the butterfly valve 17 (hereinafter referred to as “target opening”) is obtained from the engine speed and accelerator operation amount at each time. Note that such a target opening degree map can be obtained experimentally, for example.

  Then, based on the target opening and actual opening each time, a torque command value for the electric motor 20 (hereinafter referred to as “command torque”) is calculated, and the electric motor 20 is controlled based on the command torque. For example, the provisional value of the command torque is calculated based on the target opening, and the final value of the command torque is calculated by correcting the provisional value of the command torque based on the deviation between the target opening and the actual opening. Then, a duty drive signal corresponding to the command torque is output to the electric motor 20.

  As a result, in the EGR actuator 15, the pinion gear 46 rotates together with the motor shaft 44 of the electric motor 20, and accordingly, the intermediate reduction gear 47 rotates and the valve side gear 50 rotates. As a result, the valve shaft 18 rotates together with the valve side gear 50 against the biasing force of the coil spring 40, and the butterfly valve 17 is controlled to the target opening.

  Next, the operation of the EGR actuator 15 when the gear constituting the gear reduction mechanism 19 is damaged (during abnormality) will be described in detail with reference to FIGS.

  3 and 4 are views showing the operation of the EGR actuator 15 when the tooth portion of the small-diameter gear portion 49 (drive gear) of the intermediate reduction gear 47 is damaged. FIG. 5 shows the valve-side gear 50 (driven gear). It is a figure which shows the action | operation of the EGR actuator 15 when the tooth | gear part of () is damaged. 3 to 5, it is assumed that the small-diameter gear portion 49 of the intermediate reduction gear 47 is driven to the valve opening side (clockwise in the figure) against the urging force of the coil spring 40. In FIGS. 3 and 5, the tooth portion of one gear that is damaged and the tooth portion of another gear meshed at timing t1 or t10 are hatched.

(EGR actuator operation when the teeth of the small-diameter gear section are damaged)
At timing t1 shown in FIG. 3, when the tooth portion 53 adjacent to the valve opening side and the tooth portion of the valve side gear 50 are disengaged from the damaged tooth portion of the small diameter gear portion 49 (see FIG. 4A). At timings t 1 to t 2, the small-diameter gear portion 49 is rotated to the valve opening side (clockwise in the drawing) of the butterfly valve 17 by the driving force of the electric motor 20, and the valve-side gear 50 is rotated by the biasing force of the coil spring 40. Rotates to the valve closing side 17 (clockwise in the figure) (see FIG. 4B). As a result, at timings t1 to t2, the opening degree of the butterfly valve 17 changes to the valve closing side.

  At timing t2, the tooth portion of the valve side gear 50 and the tooth portion of the small diameter gear portion 49 (specifically, the damaged tooth portion of the small diameter gear portion 49 and the tooth portion 54 adjacent on the valve closing side of the butterfly valve 17). When engaged (see FIG. 4C), at timings t2 to t3, the valve side gear 50 rotates to the valve opening side (counterclockwise in the figure), and the opening degree of the butterfly valve 17 changes to the valve opening side.

  Thereafter, the small-diameter gear portion 49 makes one rotation based on the state at the timing t1, and at the timing t3, the tooth portion 53 adjacent to the damaged tooth portion of the small-diameter gear portion 49 on the valve opening side of the butterfly valve 17 and the valve-side gear. When the meshing with the tooth portion of 50 is disengaged, the valve side gear 50 is again rotated to the valve closing side (clockwise in the drawing) of the butterfly valve 17 by the urging force of the coil spring 40. At the timing t4, the tooth portion of the valve side gear 50 is adjacent to the tooth portion of the small diameter gear portion 49 (specifically, the tooth portion 53 adjacent to the damaged tooth portion 53 of the small diameter gear portion 49 on the valve closing side of the butterfly valve 17). When meshed with the portion 54), the valve side gear 50 rotates to the valve opening side (counterclockwise in the figure), and the opening degree of the butterfly valve 17 changes to the valve opening side again.

  Thus, when the tooth portion of the small-diameter gear portion 49 of the intermediate reduction gear 47 is damaged, the change in the opening degree of the butterfly valve 17 indicates a reciprocation of a predetermined width, and the reciprocation is performed for a predetermined time (because the small-diameter gear portion 49 makes one rotation). Occurs periodically after a certain period of time.

(EGR actuator operation when the tooth of the valve side gear is damaged)
At timing t10 shown in FIG. 5, when the tooth portion 56 adjacent to the valve opening side and the tooth portion of the small diameter gear portion 49 are disengaged from the damaged tooth portion of the valve side gear 50, the small diameter gear portion 49 is electrically driven. The butterfly valve 17 rotates to the valve opening side (clockwise in the figure) by the driving force of the motor 20, and the valve side gear 50 moves to the valve closing side (clockwise in the figure) of the butterfly valve 17 by the biasing force of the coil spring 40. Rotate. As a result, at timings t10 to t11, the opening degree of the butterfly valve 17 changes to the valve closing side.

  When the toothed portion 56 of the valve side gear 50 meshes with the toothed portion of the small diameter gear portion 49 at the timing t11, the valve side gear 50 is moved to the valve opening side (counterclockwise in the figure) until the timing t12 when the meshing is released thereafter. It rotates and the opening degree of the butterfly valve 17 changes to the valve opening side. The valve side gear 50 rotates to the valve closing side (clockwise in the drawing) from the timing t12 until the timing t13 when the tooth portion 56 of the valve side gear 50 meshes with the tooth portion of the small diameter gear portion 49, and the butterfly valve 17 The degree of opening again changes to the valve closing side.

  Thus, when the tooth part of the valve side gear 50 is damaged, the change in the opening degree of the butterfly valve 17 indicates continuous reciprocation (vibration) of a predetermined width.

  As described above, when the gear tooth portion constituting the gear reduction mechanism 19 is damaged, the change in the opening degree of the butterfly valve 17 indicates a reciprocation of a predetermined width, and the reciprocation repeatedly occurs. As a result, the controllability of the opening degree of the butterfly valve 17 is lowered. In addition, the tooth portions of the small-diameter gear portion 49 and the valve-side gear 50 collide vigorously (see timings t2 and t4 in FIG. 3 and timings t11 and t13 in FIG. 5), and the tooth portions of both gears are further damaged. As a result, proper opening control of the butterfly valve 17 may be disabled.

  For convenience of explanation, the case where the tooth portion of the small diameter gear portion 49 or the valve side gear 50 is broken is illustrated. However, in this explanation, the small-diameter gear portion 49 (drive gear) of the intermediate reduction gear 47 is replaced with the pinion gear 46, and the valve-side gear 50 (driven gear) is replaced with the large-diameter gear portion 48 of the intermediate reduction gear 47. This can be read as an explanation of the operation of the EGR actuator 15 when the pinion gear 46 or the large-diameter gear portion 48 is damaged.

  Therefore, in the present embodiment, a change in the opening degree of the butterfly valve 17 is monitored, and a state in which the change indicates a reciprocation of a predetermined width is represented by the gears constituting the gear reduction mechanism 19 (pinion gear 46, intermediate reduction gear 47, It is detected as a breakage of the tooth portion of the valve side gear 50). Further, when breakage of these tooth portions is detected, a predetermined fail process is performed.

  Next, based on FIG. 6, the process (gear damage detection process) which detects the damage of the tooth part of the gear which comprises the gear reduction mechanism 19 is demonstrated. FIG. 6 is a flowchart showing the flow of the gear breakage detection program. This program is executed by the ECU 22 at a predetermined cycle (every predetermined crank angle or a predetermined time cycle).

  In step S10 shown in FIG. 6, the ECU 22 acquires the maximum value Amax of the opening degree of the butterfly valve 17 (the opening degree when the change in the opening degree of the butterfly valve 17 turns from the valve opening side to the valve closing side). In subsequent step S11, the ECU 22 acquires the minimum value Amin of the opening degree of the butterfly valve 17 (the opening degree when the change in the opening degree of the butterfly valve 17 changes from the valve closing side to the valve opening side). In subsequent step S12, the ECU 22 calculates the reciprocal width W of the opening degree of the butterfly valve 17 from the difference between the maximum value Amax and the minimum value Amin.

  In subsequent step S13, the ECU 22 determines whether or not the reciprocating width W is included in a predetermined range (Wtl to Wth). Here, the predetermined ranges (Wtl, Wth) are set in consideration of the reciprocal width of the opening degree of the butterfly valve 17 when the gear teeth constituting the gear reduction mechanism 19 are damaged.

  If it is determined in step S13 that the round-trip width W is included in the predetermined range (Wtl to Wth), the ECU 22 proceeds to step S14 and determines that the round-trip width W is not included in the predetermined range (Wtl to Wth). Then, the ECU 22 ends the current gear breakage detection process.

  In step S14, the ECU 22 increments a counter value C indicating the number of times that the reciprocating width W is included in a predetermined range (Wtl to Wth). The counter value C is reset at a predetermined cycle. In subsequent step S15, the ECU 22 determines whether or not the counter value C is equal to or greater than a predetermined value K. When the ECU 22 determines that the counter value C is equal to or greater than the predetermined value K, the ECU 22 proceeds to the process of step S16. When the ECU 22 determines that the counter value C is smaller than the predetermined value K, the present gear breakage detection process ends. To do.

  In step S16, the ECU 22 maintains the butterfly valve 17 at a predetermined opening (for example, the current opening). Specifically, the ECU 22 sets the duty of the drive signal output to the electric motor 20 to a constant value. In subsequent step S <b> 17, the ECU 22 displays on the display device 23 that the gear constituting the gear reduction mechanism 19 has been damaged. Specifically, the ECU 22 turns on or blinks a warning lamp of the display device 23, for example. In addition, you may indicate with a voice that the gear which comprises the gear reduction mechanism 19 was damaged.

  According to this gear breakage detection process, when a reciprocation of a predetermined width is detected a predetermined number of times (K times) or more within a predetermined time with respect to a change in the opening degree of the butterfly valve 17, the opening degree of the butterfly valve 17 is The opening degree is maintained, and the display device 23 displays that the gear teeth constituting the gear reduction mechanism 19 are damaged.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  The state in which the change in the opening degree of the butterfly valve 17 indicates reciprocation is detected as a breakage of the gear teeth constituting the gear reduction mechanism 19. Here, in addition to the case where the gear tooth portion constituting the gear reduction mechanism 19 is damaged, it is considered that the change in the opening degree of the butterfly valve 17 indicates reciprocation in the following cases. That is, when the opening control of the butterfly valve 17 is performed so that the change in the opening of the butterfly valve 17 indicates reciprocation, or when the detected value of the opening of the butterfly valve 17 includes an error (for example, the rotation angle It is considered that when the noise is superimposed on the detection signal of the sensor 21, the change in the opening degree of the butterfly valve 17 indicates reciprocation. In this respect, since the reciprocation of the opening degree with a predetermined width (Wtl <W <Wth) is detected, it is possible to accurately detect the breakage of the gear teeth constituting the gear reduction mechanism 19.

  Further, when the reciprocation of the opening degree of the butterfly valve 17 is detected more than a predetermined number of times within a predetermined time, the breakage of the gear teeth constituting the gear reduction mechanism 19 is detected. Thereby, about the detection of the damage of the said tooth | gear part, the misdetection can be suppressed.

  In addition, when the breakage of the gear teeth constituting the gear reduction mechanism 19 is detected, the butterfly valve 17 is maintained at a predetermined opening. This avoids a collision between a damaged tooth portion of one gear constituting the gear reduction mechanism 19 and a tooth portion of another gear meshing with the one gear, and further updates the tooth portion of the gear constituting the gear reduction mechanism 19. The damage which becomes can be suppressed.

  In addition, when the breakage of the gear teeth constituting the gear reduction mechanism 19 is detected, the fact is displayed on the display device 23. As a result, by coping with the internal combustion engine 11 being stopped, it is possible to avoid collision with other gear teeth meshing with one gear and to suppress further damage to the gear teeth constituting the gear reduction mechanism 19. Can do.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be implemented as follows, for example.

  In the above embodiment, the state where the change in the opening degree of the butterfly valve 17 indicates a reciprocation of a predetermined width is detected as a breakage of the gear tooth portion constituting the gear reduction mechanism 19. However, the breakage of the tooth portion may be detected based on the reciprocation time of the opening degree of the butterfly valve 17. Here, when the change in the opening degree of the butterfly valve 17 indicates reciprocation as a result of damage to the gear teeth constituting the gear reduction mechanism 19, the reciprocation time is the driving force of the electric motor 20 and the urging force of the coil spring 40. It depends on. On the other hand, when the opening degree of the butterfly valve 17 is reciprocated as the opening degree control of the butterfly valve 17, the reciprocation time is determined only by the driving force of the electric motor 20. Moreover, when the change of the opening shows a reciprocation due to the detection error of the opening of the butterfly valve 17, the reciprocation time is considered to be relatively short. Thus, the reciprocation time of the opening degree of the butterfly valve 17 differs between the case where the gear teeth constituting the gear reduction mechanism 19 are damaged and the other cases. Therefore, by detecting the breakage of the gear teeth constituting the gear reduction mechanism 19 based on the reciprocation time of the opening degree of the butterfly valve 17 as described above, the erroneous detection can be suppressed.

  Moreover, in the said embodiment, if the failure | damage of the tooth part of the gear which comprises the gear reduction mechanism 19 is detected, as the fail process, the opening degree of the butterfly valve 17 will be maintained at the opening degree at the time of the detection, The display device 23 displays that the tooth portion of the constituent gear is broken. However, you may implement the fail process according to the reciprocation aspect of the opening degree of the butterfly valve 17. FIG. For example, as described above, when the gear teeth constituting the gear reduction mechanism 19 are further damaged, that is, the teeth adjacent to each other in the rotation direction are successively damaged with the gear teeth. Then, it is thought that the reciprocating width of the opening degree of the butterfly valve 17 becomes large. Therefore, based on the reciprocal width of the opening degree of the butterfly valve 17, a fail process corresponding to the progress of the damage of the tooth portion may be performed.

  Moreover, in the said embodiment, the damage of those tooth | gear parts was detected, without distinguishing each gear which comprises the gear reduction mechanism 19. FIG. However, based on the reciprocal width of the opening degree of the butterfly valve 17 and the reciprocal mode, the gears constituting the gear reduction mechanism 19 may be distinguished to detect breakage of their teeth. For example, in the above-described embodiment, when the reciprocation of the opening degree of the butterfly valve 17 occurs periodically at a predetermined time, the breakage of the drive gear is detected, and the reciprocation of the opening degree of the butterfly valve 17 continues. If this occurs, the failure of the driven gear may be detected. In this case, the fail process may be varied depending on the damaged gear.

  Moreover, in the said embodiment, the failure | damage of the tooth part of the gear which comprises the gear reduction mechanism 19 was detected based on whether the reciprocation width of the opening degree of the butterfly valve 17 was included in the predetermined range set beforehand. . However, the predetermined range may be variably set. For example, even if the gear teeth constituting the gear reduction mechanism 19 are damaged in the same situation, the opening of the butterfly valve 17 increases as the driving force of the electric motor 20 (duty of the driving signal to the electric motor 20) increases. The reciprocal width of the degree is considered to be small. Therefore, the predetermined range may be variably set based on the driving force of the electric motor 20 when the change in the opening degree of the butterfly valve 17 indicates reciprocation.

The figure which shows the exhaust gas recirculation apparatus which concerns on this embodiment. The figure which shows the EGR control valve which concerns on this embodiment. The figure which shows the action | operation of an EGR actuator at the time of the failure | damage of the tooth | gear part of a small diameter gear part. The figure which shows the action | operation of an EGR actuator at the time of the failure | damage of the tooth | gear part of a small diameter gear part. The figure which shows the action | operation of an EGR actuator at the time of the failure | damage of the tooth | gear part of the valve | bulb side gear. The flowchart which shows the flow of a gear breakage detection program.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Exhaust gas recirculation apparatus, 11 ... Internal combustion engine, 12 ... Exhaust passage, 13 ... Intake passage, 14 ... Exhaust gas recirculation passage (flow path), 15 ... EGR control valve, 17 ... Butterfly valve, 18 ... Valve shaft, 19 DESCRIPTION OF SYMBOLS ... Gear reduction mechanism, 20 ... Electric motor (power source), 21 ... Rotation angle sensor (opening degree detection means), 22 ... ECU (Rotation angle detection means, Tooth part breakage detection means, Fail processing means), 40 ... Coil spring (Biasing means) 46 ... pinion gear 47 ... intermediate reduction gear 48 ... large diameter gear portion 49 ... small diameter gear portion 50 ... valve side gear

Claims (11)

A driving gear; a driven gear meshing with the driving gear; a biasing means that biases the driven gear in a predetermined rotational direction; and a power source that drives the driving gear against a biasing force of the biasing means. Applied to the drive device comprising
The valve body that is driven to open and close by the drive device is provided with an opening degree detecting means for detecting the opening degree of the valve body, and the driving for controlling the opening degree of the valve body based on the detection result by the opening degree detecting means. In the control device,
Gear breakage detecting means for monitoring the opening degree detected by the opening degree detecting means and detecting a state in which the change in the opening degree indicates reciprocation as breakage of a tooth portion of the drive gear or the driven gear. A drive control device for a valve body characterized by the above.   The gear breakage detecting means detects a state in which the change in the opening degree indicates a reciprocation having a width corresponding to n teeth (n is a positive integer) as the tooth breakage. 2. The drive control device for a valve body according to 1.   The drive control device for a valve body according to claim 1 or 2, wherein the gear breakage detecting means detects breakage of the tooth portion based on a reciprocation time of the opening degree.   The drive control device for a valve body according to any one of claims 1 to 3, wherein the gear breakage detecting unit detects a state in which the reciprocation of the opening degree is repeatedly generated as breakage of the tooth portion.   5. The drive control device for a valve body according to claim 4, wherein the gear breakage detecting unit detects a state in which the reciprocation of the opening is continuously generated as breakage of the tooth portion.   6. The drive control device for a valve body according to claim 4 or 5, wherein the gear breakage detecting means detects a state in which the reciprocation of the opening degree is periodically generated after a predetermined time as the tooth portion is broken. .   The valve body drive control device according to any one of claims 1 to 6, further comprising: a fail processing unit that performs a predetermined fail process when the tooth breakage is detected by the gear breakage detection unit. .   The valve body drive control device according to claim 7, wherein the fail processing means maintains the valve body at a predetermined opening degree as the fail processing.   The valve body drive control device according to claim 7 or 8, wherein the fail processing means warns that the tooth portion is damaged as the fail processing.   The valve body drive control device according to any one of claims 7 to 9, wherein the fail processing means performs a fail processing in accordance with a reciprocating mode of the opening degree.   The opening degree of the butterfly valve which is provided in the flow path through which the exhaust or intake air of an internal combustion engine flows as the valve body and adjusts the flow rate of the intake or exhaust gas flowing through the flow path is controlled according to any one of claims 1 to 10. The drive control apparatus of the valve body as described.

Images