JP2012023873A - Electric driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely determine whether a valve body serving as a body to be driven is normally shifted from a non-restricted state to a restricted state in an electric driving device 1.SOLUTION: According to the driving device 1, control means 12 stores a threshold value Ithr regarding an energization amount for determining whether or not a rotational position normally reaches a totally closed position, when controlling the energization to an electric motor 2 so that the rotational position of the valve body is changed from a totally open position toward the totally closed position to reach the totally closed position. When the energization amount increases beyond the threshold value Ithr by a rush current, decreases subsequently to fall below the threshold value Ithr, and increases again to exceed the threshold value Ithr after starting the energization to the electric motor 2, the control means determines that the rotational position normally reached the totally closed position. Thereby, whether or not the valve body is normally shifted from the non-restricted state to the restricted state can be surely determined.

Description

  The present invention relates to an electric drive device that drives a driven body by a driving force generated by an electric motor.

  Conventionally, for example, an electric drive device that rotates a valve body as a driven body by a driving force of an electric motor is known, and intake air that is incorporated into an intake / exhaust system of an internal combustion engine and sucked into the internal combustion engine, or The present invention is applied to a valve device or the like that changes the flow rate of exhaust gas exhausted from an internal combustion engine.

  Further, the electric drive device is provided with a mechanism for mechanically restraining the driven body when the driven body is in a specific position or posture. For example, when an electric drive device is applied to a valve device (hereinafter referred to as a TCV device) for rotationally driving a tumble control valve (hereinafter referred to as a TCV device) that generates a tumble flow in a combustion chamber of an internal combustion engine. In addition, a stopper structure is provided on one member of the speed reduction mechanism, the valve shaft, or the like to mechanically restrain the driven body at the fully open position or the fully closed position.

  By the way, in such an electric drive device that mechanically restrains the driven body, when the driven body shifts from the unconstrained state to the restrained state, the energization amount to the electric motor increases stepwise. For example, in the TCV device, when the TCV is rotated toward full closure, a typical temporal change pattern of the energization amount in the electric motor is as shown in FIG. That is, after the start of energization, the energization amount temporarily increases suddenly due to the inrush current and then decreases, and then the energization amount increases stepwise as the driven body shifts from the unconstrained state to the constrained state.

  For this reason, there is an increasing demand to reliably determine whether or not the driven body has normally shifted from the unconstrained state to the restrained state without regarding such a step-like change in the energization amount as abnormal. Yes.

Note that Patent Documents 1 and 2 disclose circuit configurations and the like that are determined to be abnormal when the energization amount to the electric motor exceeds a predetermined threshold. However, in the circuit configurations of Patent Documents 1 and 2, the transition from the unconstrained state to the constrained state cannot be determined as a normal transition.
Patent Document 3 discloses that the amount of energization is integrated over time to shape the change over time in the amount of energization, thereby increasing an overcurrent due to a short circuit or the like and a normal amount of energization accompanying the transition from the unconstrained state to the restrained state. A circuit configuration or the like is disclosed. However, in the circuit configuration of Patent Document 3, even if an abnormality other than an overcurrent occurs, it may be determined that all transitions are normal, and this is not sufficient as an abnormality determination.

JP-A-8-19172 JP 2005-151766 A Japanese Patent Laid-Open No. 2001-4673

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an undriven state of the driven body in the electric drive device that drives the driven body by the driving force generated by the electric motor. It is to reliably determine whether the driven body has normally shifted from the unconstrained state to the constrained state without simply considering the step-like change in the energization amount accompanying the transition from the unconstrained state to the constrained state. .

[Means of Claim 1]
The electric drive device according to claim 1 includes an electric motor that generates a driving force by energization, a current detection unit that detects an energization amount to the electric motor, and a control unit that controls energization to the electric motor. While controlling the energization of the electric motor by the means, the driving force generated by the electric motor is transmitted to the driven body to change one or both of the position and posture of the driven body.

  In addition, if one or both of the position and orientation of the driven body that changes depending on the driving force transmitted from the electric motor is defined as the displacement amount, the displacement amount value can be changed so that the displacement amount changes in one direction. Even if the driving force is continuously transmitted from the motor to the driven body, there is a constraint value in which the driven body is mechanically constrained and the amount of displacement does not change in one direction. The energization amount to the electric motor increases in a step shape when the displacement amount reaches a constraint value after changing in one direction.

  Then, the control means determines whether or not the displacement amount has normally reached the constraint value when controlling the energization to the electric motor so that the constraint value reaches the constraint value after the displacement amount has changed in one direction. The threshold for the amount of electricity to be stored is stored, and after the start of energization to the electric motor, the amount of energization increases beyond the threshold due to the inrush current, and then decreases again so that the amount of energization falls below the threshold, and then increases again. When the threshold value is exceeded, it is determined that the displacement amount has normally reached the constraint value.

  Thereby, it is possible to determine that an abnormality other than an overcurrent is abnormal by appropriately selecting the threshold value. For this reason, whether the driven body has normally shifted from the unconstrained state to the constrained state without simply considering the step change in the energization amount accompanying the transition of the driven body from the unconstrained state to the constrained state as abnormal. It is possible to reliably determine whether or not.

[Means of claim 2]
According to the electric drive device of the second aspect, after the energization of the electric motor is started, the control means is such that the energization amount falls below the threshold and the absolute value of the temporal change rate of the energization amount is equal to or less than a predetermined convergence value. When this happens, it is determined that the temporary increase / decrease in the energization amount due to the inrush current has converged.
Factors that determine the time required for the inrush current to converge are inertia, motor degradation, load torque, and the like. Of these elements, only the inertia can be calculated strictly, and the others are uncertain elements.

  Therefore, it is necessary to set a large reference value for the time for determining whether or not the inrush current has converged in consideration of fluctuations of uncertain factors. However, when the change amount of the displacement amount is small, the time required for the driven body to transition from the unconstrained state to the constrained state is short. Therefore, if the reference value is increased, the convergence of the inrush current cannot be detected. The possibility that the driving body shifts to the restrained state is increased.

  Therefore, instead of setting a reference value for the time for determining whether or not the inrush current has converged, the determination factor is whether or not the absolute value of the temporal change rate of the energization amount is below the convergence value. Thus, it is possible to reliably detect the convergence of the inrush current regardless of the length of time required for the driven body to shift from the unconstrained state to the restrained state.

[Means of claim 3]
According to the electric drive device of claim 3, the electric motor is in sliding contact with the rotor having a plurality of armature coils and a plurality of commutator pieces, the stator having a plurality of field poles, and the commutator pieces. And two brushes for energizing the armature coil, and a rotational torque is generated by the interaction between the current flowing through the armature coil and the magnetic flux formed by the field pole.

  The control means has a lock current estimation means for estimating the lock current when the energization amount increased after reaching the constraint value is defined as the lock current, and when the displacement reaches the constraint value and the rotor stops. The lock current value Ia when both brushes are in contact with a single commutator piece without straddling a plurality of commutator pieces, and at least one brush straddling a plurality of commutator pieces. The ratio Ia / Ib with the lock current value Ib in the case of contact is stored, and the threshold value is set so as not to exceed the upper limit value obtained by multiplying the estimated value by the lock current estimating means by the ratio Ia / Ib. .

  The combined resistance of the armature coil when two brushes are both in contact with a single commutator piece without straddling a plurality of commutator pieces, is applied while at least one brush straddles a plurality of commutator pieces. It becomes larger than the combined resistance of the armature coils in contact. For this reason, the lock current value Ia is smaller than the value Ib.

Here, since it is extremely difficult to predict whether the lock current will be the value Ia or the value Ib, the estimated value is used to reliably determine the normal transition of the driven body from the unconstrained state to the restrained state. A threshold value is set so as not to exceed a numerical value (upper limit value) obtained by multiplying by Ia / Ib.
Thereby, regardless of the contact state between the brush and the commutator piece in the electric motor when the driven body is in the restrained state, it is possible to reliably determine the normal transition from the unconstrained state to the restrained state.

[Means of claim 4]
According to the electric drive device of the fourth aspect, the lock current estimating unit is configured to perform a plurality of energizations detected a plurality of times by the current detecting unit after it is determined that the displacement amount has normally reached the constraint value. The average value of the detected values of the quantity is used as the estimated value of the lock current.

[Means of claim 5]
According to a fifth aspect of the present invention, there is provided an electric drive device comprising temperature estimation means for estimating the ambient temperature of the electric motor and power supply voltage detection means for detecting the voltage of the power supply that supplies power to the electric motor. The lock current estimating means stores the ratio between the lock current and the power supply voltage as a function having the temperature around the electric motor as a variable, and the ratio of the ambient temperature around the electric motor estimated by the temperature estimating means. Calculate the ratio of the lock current and the power supply voltage by applying the estimated value to the function, and multiply the calculated ratio by the detected value of the power supply voltage detected by the power supply voltage detection means to calculate the estimated value of the lock current To do.

  The lock current has temperature characteristics and is proportional to the voltage of the power source. For this reason, if the ratio between the lock current and the voltage of the power supply is stored in advance as a function having the temperature around the electric motor as a variable, the estimated value of the temperature around the electric motor is applied to the function to obtain the lock current. The estimated value of the lock current reflecting the temperature can be calculated by multiplying the calculated ratio by the detected value of the voltage of the power source.

[Means of claim 6]
According to the electric drive device of the sixth aspect, the lock current estimation means detects the energization amount detected value obtained by the current detection means and the temperature estimation after it is determined that the displacement amount has normally reached the constraint value. The function is corrected based on the estimated value of the ambient temperature of the electric motor estimated by the means and the detected value of the power supply voltage obtained by the power supply voltage detecting means.
Thereby, even if the characteristics of the electric motor change with time and the function fluctuates, the function can be corrected with high accuracy. For this reason, even if the characteristics of the electric motor change with time, the lock current can be estimated with high accuracy.

[Means of Claim 7]
According to the electric drive device of the seventh aspect, the control means time-integrates the energization amount from the start of energization to the electric motor until the energization amount increases stepwise, and based on the obtained integrated value. It is determined whether or not the displacement amount is normal.
In many cases, a linear correlation is found between the energization amount and the temporal change rate of the displacement amount. In this case, the integrated value obtained by time integration of the energization amount and the displacement amount also have a linear correlation. Therefore, it can be determined with high accuracy whether or not the displacement amount is normal based on the integral value.

[Means of Claim 8]
According to an eighth aspect of the present invention, there is provided an electric drive device including a drive circuit for turning on / off the electric motor in response to the start and stop of input of a control signal from the control means. Further, the control means controls energization to the electric motor by outputting a PWM signal as a control signal to the drive circuit. The sampling frequency at which the control means acquires the detected value of the energization amount from the current detection means is greater than the PWM signal frequency divided by the PWM signal duty ratio.

  As a result, the detection value of the energization amount during the on-time period of the PWM signal can be reliably acquired, so that the situation where only the detection value of the energization amount during the off-time period of the PWM signal is acquired can be avoided.

(A) is a principal part block diagram of a TCV apparatus, (b) is explanatory drawing which shows the stopper structure of a TCV apparatus (Example 1). (A) is a circuit block diagram of an electric drive device, and (b) is a trend diagram showing a temporal change pattern of an energization amount in an electric motor (Example 1). (A) is explanatory drawing explaining the value Ia of a lock current in case two brushes are in contact with a single commutator piece, and (b) is one brush straddling two commutator pieces. (Example 1) explaining the value Ib of the lock current in the case of abutting while in contact. It is a main flowchart of an electric drive device (Example 1). 4 is a flowchart of a sub of the electric drive device (Example 1). 4 is a flowchart of a sub of the electric drive device (Example 1). (Example 2) which is a circuit block diagram of an electric drive device. (A) is table data of an electric drive device, (b), (c) is explanatory drawing explaining the update of the table data by an electric drive device (Example 2). (A) is a trend figure which shows the time-dependent change pattern of the energization amount in an electric motor, (b) is explanatory drawing explaining the relationship between the period of a PWM signal, and the sampling period of energization amount (Example 3). It is a trend figure which shows the time-dependent change pattern of the energization amount in an electric motor (conventional example).

  The electric drive device according to the first embodiment includes an electric motor that generates a driving force by energization, a current detection unit that detects an energization amount of the electric motor, and a control unit that controls energization of the electric motor. While controlling the energization of the electric motor by the means, the driving force generated by the electric motor is transmitted to the driven body to change one or both of the position and posture of the driven body.

  In addition, if one or both of the position and orientation of the driven body that changes depending on the driving force transmitted from the electric motor is defined as the displacement amount, the displacement amount value can be changed so that the displacement amount changes in one direction. Even if the driving force is continuously transmitted from the motor to the driven body, there is a constraint value in which the driven body is mechanically constrained and the amount of displacement does not change in one direction. The energization amount to the electric motor increases in a step shape when the displacement amount reaches a constraint value after changing in one direction.

  Then, the control means determines whether or not the displacement amount has normally reached the constraint value when controlling the energization to the electric motor so that the constraint value reaches the constraint value after the displacement amount has changed in one direction. The threshold for the amount of electricity to be stored is stored, and after the start of energization to the electric motor, the amount of energization increases beyond the threshold due to the inrush current, and then decreases again so that the amount of energization falls below the threshold, and then increases again. When the threshold value is exceeded, it is determined that the displacement amount has normally reached the constraint value.

  In addition, after the start of energization to the electric motor, the control means is configured such that when the energization amount falls below a threshold and the absolute value of the temporal change rate of the energization amount falls below a predetermined convergence value, the energization amount due to the inrush current It is determined that the temporary increase or decrease of has converged.

  Further, the electric motor includes a rotor having a plurality of armature coils and a plurality of commutator pieces, a stator having a plurality of field poles, and 2 for slidingly contacting the armature coils in contact with the commutator pieces. It has two brushes and generates rotational torque by the interaction between the current flowing through the armature coil and the magnetic flux formed by the field pole.

  The control means has a lock current estimation means for estimating the lock current when the energization amount increased after reaching the constraint value is defined as the lock current, and when the displacement reaches the constraint value and the rotor stops. The lock current value Ia when both brushes are in contact with a single commutator piece without straddling a plurality of commutator pieces, and at least one brush straddling a plurality of commutator pieces. The ratio Ia / Ib with the lock current value Ib in the case of contact is stored, and the threshold value is set so as not to exceed the upper limit value obtained by multiplying the estimated value by the lock current estimating means by the ratio Ia / Ib. .

Further, the lock current estimating means calculates the average value of the detected values of the plurality of energization amounts detected over a plurality of times by the current detecting means after it is determined that the displacement amount has normally reached the constraint value. Estimated value of
Further, the control means integrates the energization amount over time from the start of energization to the electric motor until the energization amount increases stepwise, and determines whether the displacement amount is normal based on the obtained integrated value. to decide.

  The electric drive apparatus according to the second embodiment includes temperature estimation means for estimating the ambient temperature of the electric motor, and power supply voltage detection means for detecting the voltage of the power supply that supplies power to the electric motor. The lock current estimating means stores the ratio between the lock current and the power supply voltage as a function having the temperature around the electric motor as a variable, and the ratio of the ambient temperature around the electric motor estimated by the temperature estimating means. Calculate the ratio of the lock current and the power supply voltage by applying the estimated value to the function, and multiply the calculated ratio by the detected value of the power supply voltage detected by the power supply voltage detection means to calculate the estimated value of the lock current To do.

  In addition, the lock current estimation means is configured to detect the energization amount detected by the current detection means and the surroundings of the electric motor estimated by the temperature estimation means after it is determined that the displacement amount has normally reached the constraint value. The function is corrected based on the estimated value of the temperature and the detected value of the power supply voltage obtained by the power supply voltage detecting means.

  The electric drive apparatus according to the third embodiment includes a drive circuit that turns on and off the electric motor in response to the start and stop of input of a control signal from the control unit. Further, the control means controls energization to the electric motor by outputting a PWM signal as a control signal to the drive circuit. The sampling frequency at which the control means acquires the detected value of the energization amount from the current detection means is greater than the PWM signal frequency divided by the PWM signal duty ratio.

[Configuration of Example 1]
A configuration of an electric drive device (hereinafter abbreviated as a drive device) 1 according to the first embodiment will be described with reference to FIGS.
The drive device 1 drives a driven body by the driving force generated by the electric motor 2, and is incorporated in an intake system of an internal combustion engine (not shown), for example, to generate a tumble flow in the combustion chamber of the internal combustion engine. This is applied to a TCV device 4 for rotationally driving a TCV (hereinafter referred to as a valve body) 3 to be driven as a driven body.

  That is, the TCV device 4 includes, for example, a valve body 3 that is rotatably accommodated in an intake passage 7 in the intake manifold 6 and generates a tumble flow in the combustion chamber by restricting the intake passage 7, and an electric motor 2. And a driving device 1 that rotates the valve body 3 by a rotational torque as a generated driving force.

  Here, the valve body 3 is penetrated through the valve shaft 8 so as to be fixed relative to the valve shaft 8, and is rotated by a rotational torque transmitted from the valve shaft 8. Moreover, the valve body 3 is provided in the substantially rectangular shape, and the valve shaft 8 is being fixed with respect to the valve body 3 so that it may become parallel to one set of 2 sides which make a rectangle.

  The valve body 3 is formed with a notch 9 on the side farther from the valve shaft 8 out of the two sides parallel to the valve shaft 8, and when fully closed, the valve body 3 and the flow path wall An opening corresponding to the area of the notch 9 is formed therebetween. For this reason, when the valve body 3 rotates to the fully closed position, the intake passage 7 is throttled to an area corresponding to the notch 9, and a tumble flow is generated in the combustion chamber.

  The drive device 1 includes an electric motor 2 that generates rotational torque by energization, a current detection unit 11 that detects an energization amount to the electric motor 2, a control unit 12 that controls energization to the electric motor 2, and a control unit 12. And a drive circuit 14 for turning on and off energization from the power source 13 to the electric motor 2 in response to the start and stop of input of the control signal from the control signal. This is transmitted to the valve body 3 to change the rotational position of the valve body 3.

  The electric motor 2 is in sliding contact with a rotor 18 having a plurality of armature coils 16 and a plurality of commutator pieces 17, a stator 20 having a plurality of field poles 19, and the commutator pieces 17. This is a well-known DC motor that has two brushes 21a and 21b for energizing the motor and generates rotational torque by the interaction between the current flowing through the armature coil 16 and the magnetic flux formed by the field pole 19.

  The current detection unit 11 is a well-known current detection circuit that detects the amount of current supplied to the electric motor 2 by detecting a voltage drop in the shunt resistor 24 incorporated on the ground side of the drive circuit 14 and the electric motor 2.

  The control means 12 outputs a control signal for controlling energization to the electric motor 2 based on detection signals input from various sensors such as the current detection means 11, and is a CPU that performs control processing and arithmetic processing. The microcomputer has a known structure including a storage device such as a ROM and a RAM for storing various data and programs, an input device, an output device, and the like.

  The drive circuit 14 has a well-known structure composed of four switching elements 25 that operate in response to input of control signals individually from the control means 12, and can energize the electric motor 2 in either forward or reverse direction. Is possible.

  By the way, the rotational torque generated by the electric motor 2 is transmitted to the valve shaft 8 via a known speed reduction mechanism. That is, the valve shaft 8 is press-fitted and fixed to a gear member 26 that forms a transmission terminal of rotational torque in the speed reduction mechanism, and the shaft center of the valve shaft 8 and the rotation shaft center of the gear member 26 are coaxial. Further, the gear member 26 is gradually reduced in diameter toward the valve body 3, and the distal end portion 26 a closest to the valve body 3 is supported by the intake manifold 6 by an oil seal 27.

  The valve shaft 8 is held by the gear member 26 so as to protrude from the distal end portion 26a, and an intake manifold is formed in a portion of the valve shaft 8 near the distal end portion 26a and protruding from the distal end portion 26a. 6 is provided with an engaging portion 29 that forms a stopper structure.

  The engaging portion 29 is a disc portion 30 that is perpendicular to the valve shaft 8 and perpendicular to the axis of the valve shaft 8 and has a circular center and a part of the outer peripheral edge of the disc portion 30 toward the outer peripheral side. Projecting portion 31 projecting from the valve shaft 8 and rotate integrally with the valve shaft 8. And the engaging part 29 is accommodated rotatably in the accommodating chamber 32 provided in the wall part of the intake manifold 6.

  Here, the storage chamber 32 is provided in a shape that can restrict the rotation of the engaging portion 29 by engaging with the protruding portion 31. That is, the storage chamber 32 is formed such that the first storage portion 33 having an inner diameter slightly larger than the outer peripheral edge of the disc portion 30 and the outer peripheral edge of the first storage portion 33 partially expand to the outer peripheral side. The disc portion 30 and the protruding portion 31 are accommodated in the first and second accommodating portions 33 and 34, respectively. For this reason, the wall surfaces 35 and 36 of the circumferential direction both ends of the 2nd accommodating part 34 can regulate rotation of the engaging part 29 by engaging with the protrusion part 31 (henceforth, wall surface 35 and 36, respectively). (Referred to as engagement surfaces 35 and 36).

  As described above, the valve body 3 is mechanically constrained by engaging the engagement portions 29 provided on the valve shaft 8 with the engagement surfaces 35 and 36 provided on the intake manifold 6. And the engaging part 29 engages with the engaging surface 35 of the circumferential direction one end side, for example, when the valve body 3 exists in a fully closed position, and the circumferential direction other end side when the valve body 3 exists in a fully open position. The engagement surface 36 is engaged.

  For this reason, the fully closed position related to the rotational position of the valve body 3 is such that even if rotational torque is continuously transmitted from the electric motor 2 toward the valve body 3 so that the rotational position changes to the closed side, the valve body 3 is mechanically Therefore, the rotation position is a constraint value that does not change further to the closed side. Similarly, even if the rotational torque continues to be transmitted from the electric motor 2 to the valve body 3 so that the rotational position changes to the open side, the valve body 3 is mechanically restrained and the rotational position is further increased. The constraint value does not change to the open side.

  Then, when the valve body 3 is rotated toward the constraint value while controlling the energization to the electric motor 2 by the control means 12, the engaging portion 29 is engaged with the engaging surface 35 or the engaging surface 36, and the valve The body 3 shifts from a restrained state that is not mechanically restrained to a restrained state that is mechanically restrained. And when the valve body 3 transfers to a restraint state from a restrained state, the energization amount to the electric motor 2 increases in a step shape. That is, the energization amount to the electric motor 2 increases stepwise when the rotational position of the valve body 3 reaches the constraint value.

  Here, when the valve body 3 is rotated toward the constraint value, a typical temporal change pattern of the energization amount in the electric motor 2 is as shown in FIG. That is, after the start of energization, the energization amount temporarily increases rapidly due to the inrush current and then decreases, and then the energization amount increases stepwise as the valve body 3 shifts from the unconstrained state to the constrained state. The unconstrained state is divided into an initial state in which the energization amount fluctuates in a peak shape due to an inrush current, and a rotation state in which the energization amount is stabilized at a substantially constant value and the valve body 3 rotates at a substantially constant rotational speed. The In the following description, the energization amount increased after reaching the constraint value is referred to as a lock current.

  With respect to the energization amount indicating such a temporal change pattern, the control means 12 stores a threshold value Ithr relating to the energization amount for determining whether or not the rotational position has normally reached the constraint value. When the energization amount exceeds the threshold Ithr after the temporary increase / decrease in the energization amount has converged, it is determined that the rotational position has normally reached the constraint value.

  That is, for example, when the control unit 12 controls energization to the electric motor 2 so as to reach the fully closed position that is a constraint value after the rotational position changes toward the closed side, the rotational position is set to the fully closed position. A threshold value Ithr relating to the energization amount for determining whether or not the electric motor 2 has been normally stored is stored, and after the energization of the electric motor 2 is started, the energization amount increases beyond the threshold value Ithr due to the inrush current, and the energization amount continues. After decreasing to fall below the threshold value Ithr, when it increases again and exceeds the threshold value Ithr, it is determined that the rotational position has normally reached the fully closed position.

  Further, the control means 12 determines whether or not the temporary increase / decrease of the energization amount due to the inrush current has converged, and after the energization of the electric motor 2 starts, the energization amount falls below the threshold Ithr and the energization amount time When the absolute value of the dynamic change rate becomes equal to or less than a predetermined convergence value, it is determined that the temporary increase / decrease in the energization amount due to the inrush current has converged.

  Further, the control means 12 has a function as a lock current estimation means for estimating the lock current, and when the rotation position reaches the constraint value and the rotor 18 stops, both of the two brushes 21a and 21b are The value Ia of the lock current when contacting the single commutator piece 17 without straddling the plurality of commutator pieces 17, and at least one of the brushes 21a, 21b straddling the plurality of commutator pieces 17 The ratio Ia / Ib with the lock current value Ib in the case of contact is stored, and the threshold value Ithr is set so as not to exceed the upper limit value obtained by multiplying the estimated value Iss by the lock current estimating means by the ratio Ia / Ib. Set.

  For example, as shown in FIG. 3, the electric motor 2 has three-phase armature coils 16a to 16c that are Δ-connected, and commutator pieces 17A to 17C are electrically connected to three terminals of the Δ-connection. (The resistance values of the armature coils 16a to 16c are all assumed to be the same value r).

  In this case, the lock current indicates the value Ia when, for example, the brushes 21a and 21b are in contact with only the commutator pieces 17B and 17C, respectively (see FIG. 3A). The lock current indicates the value Ib when, for example, the brush 21a is in contact with both of the commutator pieces 17A and 17B, and the brush 21b is in contact with only the commutator piece 17C (FIG. 3). (See (b)).

  That is, when the brushes 21a and 21b are in contact only with the commutator pieces 17B and 17C, respectively, the combined resistance between the brushes 21a and 21b is a value obtained by multiplying the value r by 2/3, and the brush 21a has the commutator piece 17A. , 17B, and the brush 21b is in contact only with the commutator piece 17C, the combined resistance between the brushes 21a, 21b is a value obtained by multiplying the value r by 1/2. Therefore, since the ratio Ia / Ib is 0.75, the threshold value Ithr is set to be smaller than the upper limit value obtained by multiplying the estimated value Iss by 0.75.

  In addition, when the numerical value of the ratio Ia / Ib is generalized, when the electric motor 2 is provided with only the odd number phase of 2N + 1 phase (N is a natural number), the armature coil 16 is (2N + 1) / {2 · (N + 1)}. In the case where only 2N phases (N is a natural number) are provided, (2N−1) / {2 · (N−1)}.

  In addition, the lock current estimation unit is, for example, an average of detection values of a plurality of energization amounts detected multiple times by the current detection unit 11 after it is determined that the rotation position has normally reached the fully closed position. The value is an estimated value Iss of the lock current. When calculating the estimated value Iss, a known guard process is performed on the detected value.

  The control means 12 then multiplies the estimated value Iss obtained this time by the numerical value of the ratio Ia / Ib when the valve body 3 is rotated toward the fully closed position while controlling the energization to the electric motor 2 next time. The threshold value Ithr is set so as to be smaller than the upper limit value obtained in this way, and it is determined whether or not the rotational position has normally reached the fully closed position based on the threshold value Ithr set in this way.

Furthermore, the control means 12 integrates the energization amount over time from the start of energization to the electric motor 2 until the energization amount increases stepwise, and whether the rotational position is normal based on the obtained integrated value. Determine whether.
That is, when the electric motor 2 is a DC motor, the number of rotations of the electric motor 2 is expressed as N (t) [rad / s] as a function of time t, and the energization amount is expressed as I (t) as a function of time t. N (t) and I (t) satisfy a linear correlation such as the following [Equation 1].
[Formula 1]
N (t) = ab−I (t)

The time required from the start of energization to the electric motor 2 until the energization amount increases stepwise is represented by T1 [s], and from the start of energization to the electric motor 2 until the energization amount increases stepwise. When the rotation angle of the electric motor 2 in the meantime is represented by θ [rad], θ can be calculated by definitely integrating N (t) from 0 to T1 with respect to time t. Therefore, by using [Formula 1], θ is between the numerical value obtained by definitely integrating I (t) from 0 to T1 with respect to time t as [Formula 2] below. It has a linear correlation.
[Formula 2]

  As described above, the rotational position of the valve body 3 and the rotational angle of the electric motor 2 have a one-to-one correspondence. Based on the numerical value obtained by definite integration of I (t) from 0 to T1 with respect to time t. It can be determined whether or not the rotational position is normal.

[Control Method of Example 1]
A control method using the driving device 1 of the first embodiment will be described based on the flowcharts shown in FIGS.
Here, in the main flowchart shown in FIG. 4, for example, when the initial value of the rotational position is the fully open position, the electric motor 2 is arranged such that the rotational position reaches the fully closed position after changing toward the closed side. When the energization is controlled, it is determined whether or not the rotational position has normally reached the fully closed position. And the flowchart shown in FIG. 4 starts with the energization start to the electric motor 2.

  After the start of energization, it is first determined in step S1 whether or not the initial state has shifted to the rotating state. If it is determined that the rotation state is not shifted from the initial state (NO), the process proceeds to step S2, and if it is determined that the rotation state is shifted from the initial state (YES), the process proceeds to step S3.

Here, the determination as to whether or not the state has shifted from the initial state to the rotational state is made by executing a sub-flowchart shown in FIG.
That is, in step S1-1, it is determined whether or not the absolute value of the temporal change rate of the energization amount is equal to or less than a predetermined convergence value. For example, when the absolute value of the difference between the current detection value and the previous detection value regarding the energization amount is regarded as “the absolute value of the temporal change rate of the energization amount”, and the absolute value of this difference becomes less than the convergence value , It is determined that “the absolute value of the temporal change rate of the energization amount” is equal to or less than a predetermined convergence value.

  If the absolute value of the temporal change rate of the energization amount is equal to or less than the predetermined convergence value (YES), the process proceeds to step S1-2, and the absolute value of the temporal change rate of the energization amount is equal to or less than the predetermined convergence value. If not (NO), the process proceeds to step S1-3. In step S1-3, it is determined that the rotational state has not been changed yet, and the process returns to step S1 of the main flowchart. Thereby, in step S1, it determines with having not changed to the rotation state from the initial state.

  Next, in step S1-2, it is determined whether the energization amount is smaller than the threshold value Ithr. If the energization amount is smaller than the threshold Ithr (YES), the process proceeds to step S1-4. If the energization amount is not smaller than the threshold Ithr (NO), the process proceeds to step S1-3. In step S1-3, it is determined that the rotational state has not been changed yet, and the process returns to step S1 of the main flowchart. Thereby, in step S1, it determines with having not changed to the rotation state from the initial state.

  In step S1-4, it is determined that the rotation state has been entered, and the process returns to step S1 of the main flowchart. Thereby, in step S1, it determines with having shifted to the rotation state from the initial state.

In step S2, it is determined whether the elapsed time from the start of energization has exceeded the upper limit time in the initial state. If it is determined that the upper limit time has not been exceeded (NO), the process returns to step S1, and if it is determined that the upper limit time has been exceeded (YES), the process proceeds to step S4, where it is determined that there is a sticking abnormality.
Here, the upper limit time in the initial state is normally set based on the time required for the temporary increase / decrease of the energization amount due to the inrush current to converge. Note that the sticking abnormality is, for example, an abnormality in which the valve body 3 is stuck near the fully open position and cannot rotate.

  In step S3, it is determined whether or not the rotational state has shifted to the restraint state. If it is determined that the rotational state has not shifted to the restraint state (NO), the process proceeds to step S5. If it is determined that the rotational state has shifted to the restraint state (YES), the process proceeds to step S6.

Here, the determination as to whether or not the rotation state has shifted to the restraint state is made by executing the sub-flowchart shown in FIG.
That is, in step S3-1, it is determined whether the energization amount is larger than the threshold value Ithr. If the energization amount is larger than the threshold Ithr (YES), the process proceeds to step S3-2. If the energization amount is not greater than the threshold Ithr (NO), the process proceeds to step S3-3.

  In step S3-2, it is determined that the state has shifted to the restraint state, and the process returns to step S3 of the main flowchart. Thereby, in step S3, it determines with having shifted to the restraint state from the rotation state. In step S3-3, it is determined that the state has not yet been shifted to the constrained state, and the process returns to step S3 of the main flowchart. Thereby, in step S3, it determines with having not transfered from the rotation state to the restraint state.

In step S5, it is determined whether or not the elapsed time after the transition to the rotational state has exceeded the upper limit time of the rotational state. If it is determined that the upper limit time is not exceeded (NO), the process returns to step S3. If it is determined that the upper limit time is exceeded (YES), the process proceeds to step S7.
In step S6, it is determined whether or not the elapsed time after the rotation state transition exceeds the lower limit time of the rotation state. If it is determined that the lower limit time is not exceeded (NO), the process proceeds to step S8, and it is determined that the rotational position is abnormal.

  Here, the upper limit time and the lower limit time of the rotation state are normally set based on the time required for the valve body 3 to rotate from the fully open position to the fully closed position. The rotation position abnormality is an abnormality in which the amount of rotation from the fully opened position of the valve body 3 is small, for example.

  In step S7, it is determined whether the energization amount is smaller than the disconnection value. Here, the disconnection value is a reference value for determining whether or not a disconnection has occurred in the electric motor 2. Therefore, if it determines with the energization amount being smaller than a disconnection value by step S7 (YES), it will progress to step S9 and will determine with disconnection abnormality. Further, if it is determined in step S7 that the energization amount is not smaller than the disconnection value (NO), the process proceeds to step S10 and it is determined that the idling abnormality occurs.

  The idling abnormality is an anomaly in which idling occurs in any part of the rotational torque transmission path from the electric motor 2 to the valve shaft 8. For example, the fixed coupling between the valve shaft 8 and the gear member 26 is performed. Is broken and the gear member 26 is idle with respect to the valve shaft 8.

  If it is determined in step S6 that the lower limit time has been exceeded (YES), the process proceeds to step S11, where it is determined that the rotational position has normally reached the fully closed position from the fully open position, and the process proceeds to step S12. Thus, the lock current is estimated and the main flowchart is terminated.

Here, the control means 12 functions as a lock current estimation means by executing step S12.
The normal / abnormal determination of the rotational position based on the time integration of the energization amount is performed separately from the main flowchart, and the time integration of the energization amount is performed after the start of energization of the electric motor 2. The detection values are executed by sequentially adding together the known trapezoidal formula.

[Effect of Example 1]
According to the driving device 1 of the first embodiment, the control unit 12 moves the rotation position of the valve body 3 to the electric motor 2 so that the rotation position changes from the fully open position toward the fully closed position and reaches the fully closed position, for example. When the energization of the electric motor 2 is controlled, a threshold value Ithr relating to the energization amount for determining whether or not the rotational position has normally reached the fully closed position is stored. After the energization amount has increased beyond the threshold value Ithr and subsequently decreased so that the energization amount has fallen below the threshold value Ithr, the rotation position has reached the fully closed position normally when it has increased again and exceeds the threshold value Ithr. Judge.

Thereby, by appropriately selecting the threshold value Ithr, the valve body 3 can be moved from the rotational state without simply assuming that the step change in the energization amount accompanying the transition from the rotational state of the valve body 3 to the restrained state is abnormal. It is possible to reliably determine whether or not the transition to the restraint state is normal.
If the valve body 3 is not normally shifted from the rotation state to the restraint state, it is determined that the fixing abnormality is detected in step S4, the rotation position is abnormal in step S8, the disconnection abnormality is in step S9, or the idling abnormality is in step S10. ing.

In addition, after the energization of the electric motor 2 is started, the control means 12 has an inrush current when the energization amount falls below the threshold value Ithr and the absolute value of the temporal change rate of the energization amount becomes equal to or less than a predetermined convergence value. Is converged and the initial state is determined to have shifted to the rotating state.
Thereby, even if the time required for convergence of the inrush current varies with time, the convergence of the inrush current can be reliably detected.

Further, the electric motor 2 is, for example, a well-known DC motor shown in FIG. 3, and the control means 12 has a lock current value Ia when the brushes 21a and 21b are in contact only with the commutator pieces 17B and 17C, respectively. And the ratio Ia / Ib to the lock current value Ib when the brush 21a is in contact with both the commutator pieces 17A and 17B and the brush 21b is in contact only with the commutator piece 17C. The threshold value Ithr is set so as not to exceed the upper limit value obtained by multiplying the estimated value Iss by the lock current estimating means by the ratio Ia / Ib.
As a result, the normal state of the valve body 3 from the unconstrained state to the restrained state regardless of the contact state between the brushes 21a and 21b and the commutator pieces 17A to 17C in the electric motor 2 when the valve body 3 is in the restrained state. The transition can be determined with certainty.

Further, the control means 12 integrates the energization amount over time from the start of energization to the electric motor 2 until the energization amount increases stepwise, and the rotational position of the valve body 3 is normal based on the obtained integrated value. It is determined whether or not.
In the electric motor 2, the energization amount and the rotational speed satisfy a linear correlation, and therefore, the linear correlation also exists between the integrated value obtained by integrating the energization amount with time and the rotation angle of the electric motor 2. Therefore, since the rotation angle of the electric motor 2 and the rotation position of the valve body 3 have a one-to-one correspondence, it can be determined with high accuracy whether or not the rotation position is normal based on the integral value.

[Configuration of Example 2]
As shown in FIG. 7, the drive device 1 according to the second embodiment includes a temperature estimation unit 40 that estimates the ambient temperature of the electric motor 2 (hereinafter, “ambient temperature” is abbreviated as ambient temperature), and the electric motor 2. Power supply voltage detection means 41 for detecting the voltage of the power supply 13 (hereinafter abbreviated as power supply voltage) for supplying power to the power supply. Here, the power supply voltage detection means 41 is a known voltage detection circuit, and outputs a detection signal corresponding to the power supply voltage to the control means 12. The temperature estimation means 40 is, for example, a water temperature sensor that detects the temperature of the engine coolant, and estimates the ambient temperature of the electric motor 2 by substituting the temperature of the engine coolant as the ambient temperature of the electric motor 2. To do.

  Further, as a function of the lock current estimation means, the control means 12 uses a function P (T) in which the ratio between the lock current and the power supply voltage (hereinafter referred to as “conductance at restraint”) is the variable T as the ambient temperature of the electric motor 2. ). More specifically, as shown in FIG. 8A, the control means 12 stores the ambient temperature of the electric motor 2 and the numerical values of the conductance at restraint as table data of T and P (T).

  Further, as a function of the lock current estimation unit, the control unit 12 calculates the restricted conductance by applying the estimated value of the ambient temperature of the electric motor 2 to T of the function P (T). In this case, the control means 12 calculates the restricted conductance by linear interpolation even if the estimated value of the ambient temperature of the electric motor 2 is not the numerical value itself stored as table data. Then, as a function of the lock current estimating means, the control means 12 calculates an estimated value Iss of the lock current by multiplying the calculated restricted conductance by the detected value of the power supply voltage.

  Then, the control means 12 sets the threshold value Ithr so as not to exceed the upper limit value obtained by multiplying the estimated value Iss of the lock current calculated using the restricted conductance by the ratio Ia / Ib.

  Further, the control means 12 functions as a lock current estimation means, the detected value of the energization amount obtained by the current detection means 11, the estimated value of the ambient temperature of the electric motor 2 estimated by the temperature estimation means 40, and the power supply The function P (T) is corrected based on the detected value of the power supply voltage obtained by the voltage detecting means 41. Specifically, the control unit 12 divides the detection value of the lock current detected by the current detection unit 11 by the detection value of the power supply voltage, thereby calculating the measured value P of the conductance at the time of restraint. By using this, the numerical value of the function P (T) of the table data is updated.

  For example, as shown in FIG. 8B, the estimated value of the ambient temperature of the electric motor 2 when the detected value of the lock current and the detected value of the power supply voltage used to calculate the actual value P are 0 ° C. Let Ts ° C be between 20 ° C. Then, the ratio of “difference between Ts ° C. and 0 ° C.” and “difference between 20 ° C. and Ts ° C.” is s: 1−s (where 0 <s <1), and before the update. The restricted conductance obtained by linear interpolation based on P (0) and P (20) is P (Ts), and the difference between the measured value P and P (Ts) is ΔP (Ts).

  In this case, if weighting according to Ts ° C. is performed on the numerical values of P (0) and P (20) before the update, the numerical values of P (0) and P (20) after the update are as shown in FIG. It is updated as shown in

[Effect of Example 2]
The drive device 1 according to the second embodiment includes a temperature estimation unit 40 that estimates the ambient temperature of the electric motor 2 and a power supply voltage detection unit 41 that detects a power supply voltage. The control unit 12 functions as a lock current estimation unit. Based on the table data of the ambient temperature of the electric motor 2 and the conductance at the time of restraint, the conductance at the time of restraint is calculated using the estimated value of the ambient temperature of the electric motor 2, and the detected value of the power supply voltage is further added to the calculated conductance at the time of restraint. The estimated value Iss of the lock current is calculated by multiplying.
Thereby, the estimated value Iss of the lock current can be calculated by reflecting the temperature characteristic.

Moreover, the control means 12 corrects table data based on the detected value of the energization amount of the electric motor 2, the estimated value of the ambient temperature of the electric motor 2, and the detected value of the power supply voltage as a function of the lock current estimating means.
Thereby, even if the characteristics of the electric motor 2 change with time, the numerical value of the conductance at the time of restraint of the table data can be updated with high accuracy. For this reason, even if the characteristics of the electric motor 2 change with time, the lock current can be estimated with high accuracy.

Example 3
According to the drive device 1 of the third embodiment, as shown in FIG. 9, the control unit 12 outputs a PWM signal as a control signal to the four switching elements 25 of the drive circuit 14, thereby energizing the electric motor 2. To control. The sampling frequency at which the control means 12 acquires the detected value of the energization amount from the current detection means 11 is greater than the frequency obtained by dividing the frequency of the PWM signal by the duty ratio of the PWM signal.
As a result, the detection value of the energization amount during the on-time period of the PWM signal can be acquired with certainty, so that the situation where only the detection value of the energization amount during the off-time period of the PWM signal is acquired can be avoided. .

Further, the control means 12 indicates various determination processes in the main flowchart of FIG. 4 and the sub flowcharts of FIG. 5 and FIG. We do not use for etc.
As a result, it is possible to prevent misjudgment or the like by using the detection value acquired during the off-time period of the PWM signal.

[Modification]
The mode of the driving device 1 is not limited to the first to third embodiments, and various modifications can be considered.
For example, when the initial value of the rotational position is the fully open position, the drive device 1 of the embodiment controls energization to the electric motor 2 so that the rotational position reaches the fully closed position after changing toward the closed side. In this case, the normal / abnormal determination is made regarding the transition to the restraint state. For example, when the initial value of the rotational position is the fully closed position, the rotational position changes toward the open side. Even when energization of the electric motor 2 is controlled so as to reach the fully open position, it is possible to determine whether the electric motor 2 is normal or abnormal with respect to the transition to the restraint state.

In addition, when a restraint state exists at an intermediate position between the fully open position and the fully closed position, even when controlling the energization of the electric motor 2 so as to reach the intermediate position, normal or abnormal regarding the transition to the restraint state Can be determined.
In addition, the drive device 1 of the embodiment is applied to the TCV device 4. However, for example, the drive device 1 may be applied to a throttle device, and a part of exhaust gas is introduced into an intake system and applied to an internal combustion engine. The drive device 1 may be applied to an EGR device for inhalation.

In addition, the valve body 3 as a driven body driven by the driving device 1 of the embodiment is a butterfly valve that rotates around the valve shaft 8, but the driven body is not limited to other poppet valves, needle valves, or the like. The driven body may be driven by the driving device 1 in a shape.
Further, according to the driving device 1 of the embodiment, the displacement amount that is the target of the constraint value is the rotational position of the valve body 3. For example, when the valve body 3 is a poppet valve or the like, the displacement amount The drive device 1 may be applied as a linear movement amount of the valve body 3.

DESCRIPTION OF SYMBOLS 1 Drive device 2 Electric motor 3 Valve body (driven body)
11 current detection means 12 control means (lock current estimation means)
13 Power supply 14 Drive circuit 16, 16a-16c Armature coil 17, 17A-17C Commutator piece 18 Rotor 19 Field pole 20 Stator 21a, 21b Brush 40 Temperature estimation means 41 Power supply voltage detection means Ithr Threshold Iss Estimate lock current value

Claims (8)

An electric motor that generates a driving force by energization, a current detection unit that detects an energization amount to the electric motor, and a control unit that controls energization to the electric motor,
Electric drive that transmits a driving force generated by the electric motor to a driven body while controlling energization to the electric motor by the control means, and changes one or both of the position and posture of the driven body. In the device
If one or both of the position and orientation of the driven body that change due to the driving force transmitted from the electric motor is defined as a displacement amount,
Even if the driving force continues to be transmitted from the electric motor to the driven body so that the displacement amount changes in one direction, the driven body is mechanically constrained to the displacement amount. There is a constraint value that does not change in one direction,
When the amount of energization to the electric motor reaches the constraint value after the displacement amount changes in one direction, the amount increases in a stepped manner.
The control means includes
In order to determine whether or not the displacement amount has normally reached the constraint value when controlling the energization to the electric motor so as to reach the constraint value after the displacement amount has changed in one direction. Remembers the threshold value for the energization amount of
After the start of energization to the electric motor, the energization amount increases beyond the threshold due to the inrush current, and after the energization amount decreases to fall below the threshold, then increases again and exceeds the threshold, It is determined that the displacement amount has normally reached the constraint value. The electric drive device according to claim 1,
After the energization of the electric motor is started, the control means energizes the inrush current when the energization amount falls below the threshold and the absolute value of the temporal change rate of the energization amount becomes a predetermined convergence value or less. It is determined that the temporary increase / decrease in amount has converged. In the electric drive device according to claim 1 or 2,
The electric motor is
A rotor having a plurality of armature coils and a plurality of commutator pieces, a stator having a plurality of field poles, and two brushes for slidingly contacting the commutator pieces and energizing the armature coils. And
Rotational torque is generated by the interaction between the current flowing through the armature coil and the magnetic flux formed by the field pole,
The control means includes
When the energization amount increased after reaching the constraint value is defined as a lock current, it has a lock current estimation means for estimating the lock current,
When the displacement reaches the constraint value and the rotor stops, the two brushes are both in contact with the single commutator piece without straddling the plurality of commutator pieces. A ratio Ia / Ib between the lock current value Ia and the lock current value Ib when at least one of the brushes is in contact with the plurality of commutator pieces.
The electric drive apparatus characterized in that the threshold value is set so as not to exceed an upper limit value obtained by multiplying the estimated value obtained by the lock current estimating means by the ratio Ia / Ib. In the electric drive device according to claim 3,
The lock current estimation means includes
After it is determined that the displacement amount has normally reached the constraint value, an average value of detection values of a plurality of energization amounts detected a plurality of times by the current detection means is used as an estimated value of the lock current. An electric drive device characterized by that. In the electric drive device according to claim 3,
Temperature estimation means for estimating the ambient temperature of the electric motor;
Power supply voltage detection means for detecting the voltage of a power supply for supplying power to the electric motor,
The lock current estimation means includes
The ratio between the lock current and the voltage of the power source is stored as a function with the temperature around the electric motor as a variable,
By applying an estimated value of the ambient temperature of the electric motor estimated by the temperature estimation means to the function, a ratio between the lock current and the power supply voltage is calculated, and the power supply voltage detection means is calculated based on the calculated ratio. The estimated value of the lock current is calculated by multiplying the detected value of the voltage of the power source detected by the electric drive device. In the electric drive device according to claim 5,
The lock current estimation means includes
After it is determined that the displacement amount has normally reached the constraint value, the detection value of the energization amount obtained by the current detection unit, the estimation of the ambient temperature of the electric motor estimated by the temperature estimation unit The electric drive device, wherein the function is corrected based on a value and a detected value of the voltage of the power source obtained by the power source voltage detecting means. In the electric drive device according to any one of claims 1 to 6,
The control means includes
From the start of energization to the electric motor until the energization amount increases stepwise, the energization amount is integrated over time,
An electric drive device characterized by determining whether or not the displacement amount is normal based on the obtained integral value. In the electric drive device according to any one of claims 1 to 7,
A drive circuit for turning on and off the energization of the electric motor in response to an input start and an input stop of a control signal from the control means;
The control means controls the energization to the electric motor by outputting a PWM signal to the drive circuit as the control signal,
The electric drive apparatus according to claim 1, wherein a sampling frequency at which the control means acquires a detected value of the energization amount from the current detection means is greater than a frequency obtained by dividing the frequency of the PWM signal by the duty ratio of the PWM signal.

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