Motor controller

Abstract

To provide a motor controller capable of reducing power consumption.SOLUTION: A motor controller 1 for controlling a motor M which drives an electrically-driven device includes: a target current information acquisition part 10 for acquiring target current information which indicates a target current value of current applied to the motor M; an actual current information acquisition part 11 for acquiring actual current information which indicates an actual current value of current which actually flows through the motor M; and a voltage value setting part 13 for setting a voltage value of voltage applied to the motor M. The voltage value setting part 13 decreases the voltage value when the actual current value exceeds the target current value, and increases the voltage value when the actual current value falls below the target current value.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a motor control device that controls a motor for driving an electric device.

Background Art

[0002] Conventionally, a motor has been used to drive an electric device. As an electric device driven by such a motor, for example, there is an electric valve opening / closing timing control device that controls the opening / closing timing of at least one of the intake valve and the exhaust valve of an internal combustion engine. As a technique related to the electric valve opening / closing timing control device, for example, there is one described in Patent Document 1 cited below.

[0003] Patent Document 1 describes a control system for variable valve timing in an internal combustion engine. In this control system, with respect to the variable valve timing mechanism, based on the detection result of a cam angle sensor that detects the angle of an intake cam or / and an exhaust cam provided in the engine, only the electric power necessary for operation is energized within the range of the cam angle at which the cam torque becomes negative.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to change the performance of an internal combustion engine having a plurality of cylinders, the opening and closing timing of at least one of the intake valve and the exhaust valve of the internal combustion engine is changed. In order to ensure the required conversion speed at that time, electric power or current is required. In order to reduce such electric power or current, for example, it is conceivable to control the energization of the motor at a timing when the cam torque is negative (before crossing the cam peak) and stop the energization at a timing when the cam torque is positive (after crossing the cam peak). However, such control is not sufficient for reducing power consumption or current consumption.

[0006] In addition, general control of an electric valve opening and closing timing control device includes conversion speed constant control for making the conversion speed constant and voltage constant control for making the applied voltage constant. In the conversion speed constant control, when the conversion speed is low, the voltage or power is increased, and when the conversion speed is high, the voltage or power is decreased. When the control system described in Patent Document 1 controls the variable valve timing mechanism with conversion speed constant control, the current consumption increases when the voltage or power is increased. Also, when the control system described in Patent Document 1 controls the variable valve timing mechanism with voltage constant control, a certain amount of current flows. Therefore, in the control system described in Patent Document 1, there is room for improvement in reducing power consumption.

[0007] Therefore, a motor control device capable of reducing power consumption is required.

Means for Solving the Problems

[0008] A characteristic configuration of a motor control device according to the present invention is a motor control device that controls a motor for driving an electric device, and includes a target current information acquisition unit that acquires target current information indicating a target current value of a current flowing through the motor, an actual current information acquisition unit that acquires actual current information indicating an actual current value of a current actually flowing through the motor, and a voltage value setting unit that sets a voltage value of a voltage applied to the motor. The voltage value setting unit is configured to lower the voltage value when the actual current value exceeds the target current value and raise the voltage value when the actual current value is lower than the target current value.

[0009] With such a characteristic configuration, when the load on the motor increases and the actual current exceeds the target current value, the voltage value of the applied voltage applied to the motor is lowered to reduce the output of the motor. When the load on the motor decreases and the actual current falls below the target current value, the voltage value of the applied voltage applied to the motor is increased to increase the output of the motor. As a result, it is possible to reduce the power consumption when the load on the motor increases, and to suppress a decrease in the rotational speed of the motor when the load on the motor decreases.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] The motor control device controls a motor that drives an electric device. An electric device is a device that is operated by electric energy, and in the present invention, it is driven by a motor. In the present embodiment, an electric valve opening / closing timing control device will be described as an example of the electric device. Therefore, the motor control device controls a motor that drives an electric valve opening / closing timing control device. Hereinafter, the motor control device 1 in the present embodiment will be described. However, the motor control device 1 is not limited to the following embodiments, and various modifications are possible without departing from the gist thereof.

[0012] As described above, the motor control device 1 controls a phase control motor (an example of a "motor") M that drives the electric valve opening / closing timing control device 100. FIG. 1 is a cross-sectional view of the valve opening / closing timing control device 100. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

[0013] As shown in FIG. 1, the valve opening / closing timing control device 100 includes a driving-side rotating body A, a driven-side rotating body B, and a phase adjustment mechanism C. The driving-side rotating body A rotates synchronously with the crankshaft 101 of the engine E as an internal combustion engine about the rotation axis core X. The driven-side rotating body B is coaxial with the rotation axis core X and is disposed inside the driving-side rotating body A. Further, the driven-side rotating body B rotates integrally with an intake camshaft 102 (an example of a camshaft) that opens and closes the intake valve 102B of the engine E. The phase adjustment mechanism C sets the relative rotational phase between the driving-side rotating body A and the driven-side rotating body B by the driving force of the phase control motor M.

[0014] The engine E is configured as a four-cycle type in which pistons 104 are accommodated in a plurality of cylinders 103 formed in a cylinder block, and the pistons 104 are connected to the crankshaft 101 by connecting rods 105. A timing chain 106 (a timing belt or the like may also be used) is wound around the output sprocket 101S of the crankshaft 101 of the engine E and the drive sprocket 111S of the driving-side rotating body A.

[0015] Thereby, when the engine E is operating, the entire valve opening / closing timing control device 100 rotates about the rotation axis core X. Further, the driving force of the phase control motor M operates the phase adjustment mechanism C, making it possible to displace the driven-side rotating body B in the same direction or the opposite direction as the rotation direction with respect to the driving-side rotating body A. The relative rotational phase between the driving-side rotating body A and the driven-side rotating body B is set by the displacement in this phase adjustment mechanism C, and control of the opening / closing timing (opening / closing timing) of the intake valve 102B by the cam portion 102A of the intake camshaft 102 is realized.

[0016] Note that the operation in which the driven-side rotating body B is displaced in the same direction as the rotation direction of the driving-side rotating body A is called an advanced angle operation, and the intake compression ratio increases due to this advanced angle operation. Further, the operation in which the driven-side rotating body B is displaced in the opposite direction to the driving-side rotating body A (operation in the direction opposite to the advanced angle operation) is called a retarded angle operation, and the intake compression ratio decreases due to this retarded angle operation.

[0017] As shown in FIG. 1, the driving-side rotating body A is configured by fastening an outer case 111 having a drive sprocket 111S formed on its outer periphery and a front plate 112 with a plurality of fastening bolts 113. The outer case 111 is a bottomed cylindrical type having an opening at the bottom. The front plate 112 is provided on the side opposite to the intake camshaft 102 with respect to the eccentric member 126 in the direction along the rotation axis X.

[0018] As shown in FIGS. 1 and 2, an intermediate member 120 as the driven-side rotating body B and a phase adjustment mechanism C having a hypoid gear reduction mechanism are accommodated in the internal space of the outer case 111. Further, the phase adjustment mechanism C includes an Oldham coupling Cx that reflects the phase change on the driving-side rotating body A and the driven-side rotating body B.

[0019] The intermediate member 120 constituting the driven-side rotating body B is integrally formed with a support wall portion 121 that is connected to the intake camshaft 102 in a posture orthogonal to the rotation axis X and a cylindrical wall portion 122 that protrudes from the outer peripheral edge of the support wall portion 121 in a direction away from the intake camshaft 102 with the rotation axis X as the center.

[0020] This intermediate member 120 is fitted so as to be relatively rotatable in a state where the outer surface of the cylindrical wall portion 122 is in contact with the inner surface of the outer case 111, and is fixed to the end portion of the intake camshaft 102 by a connecting bolt 123 inserted through the through hole at the center of the support wall portion 121. It is configured such that the end portion on the outer side (the side farther from the intake camshaft 102) of the cylindrical wall portion 122 is located inside the front plate 112 in the fixed state.

[0021] As shown in FIGS. 1 and 2, a groove portion 122a is formed over the entire circumference on the outer peripheral side of the cylindrical wall portion 122. The groove portion 122a improves the retention of lubricating oil between the outer surface of the cylindrical wall portion 122 and the inner surface of the outer case 111. As a result, the frictional force between the cylindrical wall portion 122 and the outer case 111 is reduced, and the intermediate member 120 rotates smoothly with respect to the outer case 111.

[0022] As shown in FIG. 1, the phase control motor M is supported by the engine E by a support frame 107 so that its output shaft Ma is arranged coaxially with the rotation axis core X. A pair of engagement pins 108 in a posture orthogonal to the rotation axis core X are formed on the output shaft Ma of the phase control motor M.

[0023] As shown in FIGS. 1 to 3, the phase adjustment mechanism C includes an intermediate member 120, an output gear 125 formed on the inner peripheral surface of the cylindrical wall portion 122 of the intermediate member 120, an eccentric member 126, an elastic member S, a first bearing 128, a second bearing 129, an input gear 130, a fixed ring 131, a ring-shaped spacer 132, and an Oldham coupling Cx. Note that rolling bearings are used for the first bearing 128 and the second bearing 129, but sliding bearings can also be used. In the present embodiment, the first bearing 128 is a ball bearing having an inner ring 128a that contacts the outer peripheral surface of the eccentric member 126 and an outer ring 128b that contacts the inner peripheral surface of the intermediate member 120. The second bearing 129 is a ball bearing having an inner ring 129a that contacts the outer peripheral surface of the eccentric member 126 and an outer ring 129b that contacts the inner peripheral surface of the input gear 130.

[0024] As shown in FIG. 1, among the inner circumference of the cylindrical wall portion 122 of the intermediate member 120, a support surface 122S centered on the rotation axis core X is formed on the inner side (at a position adjacent to the support wall portion 121) in the direction along the rotation axis core X (hereinafter referred to as the axial direction), and an output gear 125 centered on the rotation axis core X is integrally formed outside the support surface 122S (on the side farther from the intake camshaft 102).

[0025] As shown in FIGS. 1 to 3, the eccentric member 126 is cylindrical. The eccentric member 126 has a circumferential support surface 126S on the outer peripheral surface centered on the rotation axis X on the inner side in the axial direction (the side closer to the intake camshaft 102). Further inward in the axial direction of the circumferential support surface 126S (even closer to the intake camshaft 102), a flange portion 126Q is formed that protrudes further radially outward from the circumferential support surface 126S. Further, the eccentric member 126 has an eccentric support surface 126E on the outer peripheral surface centered on the eccentric axis Y that is eccentric in a posture parallel to the rotation axis X on the outer side (the side far from the intake camshaft 102). Therefore, the eccentric member 126 is formed with the flange portion 126Q, the circumferential support surface 126S, and the eccentric support surface 126E arranged in this order along the axial direction from the side closer to the intake camshaft 102. Since the direction along the eccentric axis Y is the same as the axial direction, hereinafter, the direction along the eccentric axis Y will also be simply referred to as the axial direction.

[0026] As shown in FIGS. 1 and 3, a first concave portion 170 that is recessed inward along the radial direction of the eccentric member 126 is formed in the eccentric support surface 126E. On the bottom surface of the first concave portion 170, at both ends in the circumferential direction of the eccentric member 126, a pair of second concave portions 179, 179 that are recessed toward the radial axis side of the eccentric member 126 are formed. In the present embodiment, the first concave portion 170 is symmetric in the circumferential direction.

[0027] The second concave portions 179, 179 are respectively formed at the respective ends in the circumferential direction of the eccentric member 126 in the first concave portion 170. The maximum depth of the bottom surfaces of the second concave portions 179, 179 in the radial direction of the eccentric member 126 is deeper than the depth of the bottom surface near the center in the circumferential direction of the eccentric member 126 in the first concave portion 170. The surfaces from the respective bottom surfaces of the second concave portions 179, 179 to the ends in the circumferential direction of the eccentric member 126 are formed in a shape that follows the curved shape of a spring member 171 described later.

[0028] An elastic member S is fitted into the first concave portion 170. The elastic member S includes a pair of spring members 171, 171. In the present embodiment, the pair of spring members 171, 171 have the same shape and the same size respectively. The elastic member S applies a biasing force to the input gear 130 via the second bearing 129 so that a part of the outer tooth portion 130A of the input gear 130 meshes with a part of the inner tooth portion 125A of the output gear 125. Thereby, an increase in backlash between the input gear 130 and the output gear 125 can be prevented, and abnormal noise can be prevented. Further, thereby, the durability of the input gear 130 and the output gear 125 can be improved.

[0029] As shown in FIGS. 1 and 3, a pair of engagement grooves 126T, each of which can engage with a pair of engagement pins 108 of the phase control motor M (see FIG. 1), are formed in the inner periphery of the eccentric member 126 in a posture parallel to the rotation axis core X.

[0030] As shown in FIG. 3, tapered portions 126c (inclined portions) whose diameters become smaller toward the inner side (the side closer to the intake camshaft 102) are formed on both side portions of the engagement groove 126T on the inner peripheral side of the open end on the outer side (the side far from the intake camshaft 102) of the eccentric member 126. When engaging the pair of engagement pins 108 of the phase control motor M with the engagement groove 126T of the eccentric member 126, the engagement pins 108 are guided by the tapered portions 126c into the engagement groove 126T, so that the engagement operation between the phase control motor M and the eccentric member 126 becomes easy.

[0031] As shown in FIG. 1, the first bearing 128 is externally fitted to the circumferential support surface 126S of the eccentric member 126, and the first bearing 128 is fitted into the support surface 122S of the cylindrical wall portion 122, whereby the eccentric member 126 is rotatably supported with respect to the intermediate member 120 about the rotation axis core X. Further, as shown in FIG. 1, the input gear 130 is rotatably supported about the eccentric axis core Y with respect to the eccentric support surface 126E of the eccentric member 126 via the second bearing 129.

[0032] In this phase adjustment mechanism C, the number of teeth of the external tooth portion 130A of the input gear 130 is set to be one tooth less than the number of teeth of the internal tooth portion 125A of the output gear 125. And a part of the external tooth portion 130A of the input gear 130 meshes with a part of the internal tooth portion 125A of the output gear 125.

[0033] As shown in FIG. 1, the fixed ring 131 is supported in a fitted state on the outer periphery of the eccentric member 126, thereby preventing the second bearing 129 from coming off via the spacer 132.

[0034] As shown in FIG. 1, a gap is formed between the eccentric member 126 and the support wall portion 121 of the intermediate member 120.

[0035] As shown in FIGS. 1-3, the Oldham coupling Cx is composed of a plate-shaped coupling member 140 integrally formed with a central annular portion 141, a pair of external engagement arms 142 protruding radially outward from the annular portion 141 along the first direction (the left-right direction in FIG. 2), and an internal engagement arm 143 protruding radially outward from the annular portion 141 along the second direction (the up-down direction in FIG. 2) orthogonal to the first direction. An engagement recess 143a connected to the opening of the annular portion 141 is formed in each of the pair of internal engagement arms 143.

[0036] At the opening edge portion of the outer case 111, one or more pocket portions 111c whose inner peripheral side is cut out along the circumferential direction are formed at positions other than the guide groove portion 111a. Foreign matters that move to the outer peripheral side by receiving the centrifugal force due to the rotation of the drive-side rotating body A are collected in the pocket portion 111c. FIGS. 2 and 3 illustrate the case where four pocket portions 111c are formed.

[0037] Also, a pair of engagement protrusions 130T are integrally formed on the end face of the input gear 130 facing the front plate 112. The engagement width of the engagement protrusion 130T is set to be slightly narrower than the engagement width of the engagement recess 143a of the internal engagement arm 143.

[0038] With such a configuration, the ordinal joint Cx can be made to function by engaging a pair of outer engagement arms 142 of the joint member 140 with a pair of guide groove portions 111a of the outer case 111, and engaging a pair of engagement protrusions 130T of the input gear 130 with engagement recesses 143a of a pair of inner engagement arms 143 of the joint member 140.

[0039] Note that the joint member 140 can be displaced in a first direction (the left - right direction in FIG. 2) in which the outer engagement arms 142 extend with respect to the outer case 111, and the input gear 130 can be displaced in a second direction (the up - down direction in FIG. 2) along the formation direction of the engagement recesses 143a of the inner engagement arms 143 with respect to the joint member 140.

[0040] As shown in FIGS. 1 and 3, the spacer 132 sets the distance of the gap in which the second bearing 129 can move in the axial direction to a predetermined set value or less. By providing the spacer 132 between the ordinal joint Cx (joint member 140) and the second bearing 129, the movement of the second bearing 129 in the axial direction is restricted to a distance of a predetermined set value or less. Further, on the surface of the front plate 112 facing the input gear 130, a recess 112d recessed toward the outside (the side far from the intake camshaft 102) is formed. The recess 112d is provided to face the opening portion of the joint member 140 in the front plate 112, and the recess 112d is formed slightly wider than the opening portion of the joint member 140. Thereby, contact between the engagement protrusion 130T of the input gear 130 and the front plate 112 can be prevented.

[0041] In the assembled valve opening / closing timing control device 100, as shown in FIG. 1, a support wall portion 121 of an intermediate member 120 is connected to an end portion of the intake camshaft 102 by a connecting bolt 123, and these rotate integrally. The eccentric member 126 is supported by a first bearing 128 so as to be relatively rotatable about a rotation axis X with respect to the intermediate member 120. As shown in FIG. 1, the input gear 130 is supported via a second bearing 129 with respect to an eccentric support surface 126E of the eccentric member 126, and a part of an outer tooth portion 130A of the input gear 130 meshes with a part of an inner tooth portion 125A of the output gear 125.

[0042] Further, as shown in FIG. 2, the outer engagement arm 142 of the Ordam joint Cx engages with a pair of guide groove portions 111a of the outer case 111, and the engagement protrusion 130T of the input gear 130 engages with the engagement recess 143a of the inner engagement arm 143 of the Ordam joint Cx. Since the front plate 112 is disposed on the outer side of the joint member 140 of the Ordam joint Cx as shown in FIG. 1, the joint member 140 can move in a direction orthogonal to the rotation axis X while being in contact with the inner surface of the front plate 112. With this arrangement, the Ordam joint Cx is disposed outside both the first bearing 128 and the second bearing 129 (on the side far from the intake camshaft 102) and inside the front plate 112 (on the side close to the intake camshaft 102).

[0043] Then, as shown in FIG. 1, a pair of engagement pins 108 formed on the output shaft Ma of the phase control motor M engage with the engagement groove 126T of the eccentric member 126.

[0044] The phase control motor M is controlled by a motor control device 1 (see FIG. 4). The engine E is provided with sensors capable of detecting the rotational speeds (number of rotations per unit time) of the crankshaft 101 and the intake camshaft 102, and their respective rotational phases, and the detection signals of these sensors are configured to be input to the control device.

[0045] The control device maintains the relative rotational phase by driving the phase control motor M at a speed equal to the rotational speed of the intake camshaft 102 during the operation of the engine E. On the other hand, an advancing operation is performed by reducing the rotational speed of the phase control motor M below the rotational speed of the intake camshaft 102, and conversely, a retarding operation is performed by increasing the rotational speed. As described above, the intake compression ratio increases due to the advancing operation, and the intake compression ratio decreases due to the retarding operation.

[0046] When the phase control motor M rotates at the same speed as the outer case 111 (the same speed as the intake camshaft 102), the position of the meshing portion of the outer tooth portion 130A of the input gear 130 with respect to the inner tooth portion 125A of the output gear 125 does not change, so the relative rotational phase of the driven-side rotating body B with respect to the driving-side rotating body A is maintained.

[0047] On the other hand, by driving and rotating the output shaft Ma of the phase control motor M at a speed higher or lower than the rotational speed of the outer case 111, in the phase adjustment mechanism C, the eccentric shaft center Y revolves around the rotation shaft center X. Due to this revolution, the position of the meshing portion of the outer tooth portion 130A of the input gear 130 with respect to the inner tooth portion 125A of the output gear 125 is displaced along the inner circumference of the output gear 125, and a rotational force acts between the input gear 130 and the output gear 125. That is, a rotational force centered on the rotation shaft center X acts on the output gear 125, and a rotational force that tries to rotate the input gear 130 around the eccentric shaft center Y acts on the input gear 130.

[0048] As described above, since the engaging projection 130T of the input gear 130 engages with the engaging recess 143a of the internal engaging arm 143 of the joint member 140, the input gear 130 does not rotate with respect to the outer case 111, and the rotational force acts on the output gear 125. Due to the action of this rotational force, the intermediate member 120 rotates around the rotation shaft center X with respect to the outer case 111 together with the output gear 125. As a result, the relative rotational phase between the driving-side rotating body A and the driven-side rotating body B is set, and the setting of the opening and closing timing by the intake camshaft 102 is realized.

[0049] Also, when the eccentric shaft center Y of the input gear 130 revolves around the rotation shaft center X, along with the displacement of the input gear 130, the joint member 140 of the Oldham joint Cx is displaced in the direction (first direction) in which the external engaging arm 142 extends with respect to the outer case 111, and the input gear 130 is displaced in the direction (second direction) in which the internal engaging arm 143 extends.

[0050] As described above, since the number of teeth of the external tooth portion 130A of the input gear 130 is set to be one tooth less than the number of teeth of the internal tooth portion 125A of the output gear 125, when the eccentric axis Y of the input gear 130 revolves once around the rotation axis X, the output gear 125 rotates by one tooth, realizing a large reduction ratio.

[0051] Figure 4 is a block diagram schematically showing the configuration of the motor control device 1. The motor control device 1 includes a target current information acquisition unit 10, an actual current information acquisition unit 11, a torque information acquisition unit 12, a voltage value setting unit 13, and a control unit 14. Each functional unit is constructed by hardware or software or both with a CPU as the core member to perform processing related to the control of the phase control motor M.

[0052] The target current information acquisition unit 10 acquires target current information indicating the target current value of the current supplied to the phase control motor M. The target current value is set, for example, by the upper system of the motor control device 1 according to the required torque required for the phase control motor M. The required torque corresponds to the relative rotation phase of the driving-side rotating body A and the driven-side rotating body B required by the valve opening / closing timing control device 100. Therefore, when a current with the target current value is supplied to the phase control motor M, the valve opening / closing timing control device 100 realizes the desired relative rotation phase. The target current information acquisition unit 10 acquires such target current information indicating the target current value.

[0053] The actual current information acquisition unit 11 acquires actual current information indicating the actual current value of the current actually flowing through the phase control motor M. The actual current value corresponds to the actually measured value of the current flowing through the phase control motor M. Such an actual current value may be actually measured by a current sensor, or alternatively, the terminal voltage in the phase control motor M may be applied to a predetermined resistor, and the potential difference across both ends of this resistor may be measured accordingly. Of course, it may be measured by other methods. The actual current information acquisition unit 11 acquires such actual current information indicating the actual current value.

[0054] The voltage value setting unit 13 sets the voltage value of the voltage applied to the phase control motor M. When the actual current value exceeds the target current value, the voltage value setting unit 13 sets the voltage value low, and when the actual current value is lower than the target current value, the voltage value setting unit 13 sets the voltage value high. By setting the voltage value low when the actual current value exceeds the target current value, power consumption can be suppressed. Also, by setting the voltage value high when the actual current value is lower than the target current value, the rotational speed can be increased and the responsiveness can be improved.

[0055] Further, the motor control device 1 in the present embodiment can also be configured to change the voltage value of the voltage applied to the phase control motor M based on torque information indicating the torque generated in the drive target driven by the valve opening / closing timing control device 100.

[0056] In this case, the torque generated in the drive target driven by the valve opening / closing timing control device 100 may be treated as the torque generated in the phase adjustment mechanism C driven by the valve opening / closing timing control device 100. Torque information indicating such torque is acquired by the torque information acquisition unit 12. The torque generated in the phase adjustment mechanism C corresponds to the torque acting on the phase control motor M when the driven-side rotating body B is relatively rotated with respect to the drive-side rotating body A. Specifically, it corresponds to the cam torque generated when the intake camshaft 102 opens and closes the intake valve 102B. In the present embodiment, such cam torque is not directly measured, but is estimated based on the detection signals of sensors capable of detecting the rotational speeds (number of rotations per unit time) of the crankshaft 101 and the intake camshaft 102 described above and their respective rotational phases, and the estimated result is treated as the cam torque.

[0057] When the torque information acquisition unit 12 is configured to acquire torque information indicating the torque generated in the phase adjustment mechanism C, it is preferable that the voltage value setting unit 13 is configured to increase the voltage value when the torque is a positive value and decrease the voltage value when the torque is a negative value. Thereby, the output torque of the phase control motor M when the torque is a positive value becomes larger, and the output torque of the phase control motor M when the torque is a negative value becomes smaller, so that the effect of reducing power consumption can be made greater.

[0058] Also, according to the above configuration, since the relative rotation speed is high, depending on the valve opening / closing timing control device 100, a stopper may be provided to prevent damage due to collision when the relative rotation phase is maximum. In this case, the voltage value setting unit 13 may lower the voltage value of the voltage applied to the phase control motor M immediately before the relative rotation phase reaches the maximum. That is, the voltage value setting unit 13 may lower the voltage value of the voltage applied to the phase control motor M before hitting the stopper based on the detection signal of the sensor capable of detecting the rotation phase described above. Thereby, even when the relative rotation speed is increased, damage due to collision can be prevented.

[0059] The control unit 14 applies the voltage of the voltage value set by the above-described voltage value setting unit 13 to the phase control motor M of the valve opening / closing timing control device 100 and drives it. Also, although not shown, a detection signal of a sensor capable of detecting the rotation speed (number of rotations per unit time) of the above-described crankshaft 101 and intake camshaft 102 and their respective rotation phases is transmitted to the control unit 14. The control unit 14 transmits these detection signals and / or the calculation results based on the detection signals to the voltage value setting unit 13 and the torque information acquisition unit 12.

[0060] FIG. 5 shows a characteristic diagram of the phase control motor M. In FIG. 5, the horizontal axis is the torque output from the phase control motor M, the left vertical axis is the rotation speed of the phase control motor M, and the right vertical axis is the current flowing through the phase control motor M. For example, in the relationship between torque and current, as the torque increases, the current value of the current flowing through the phase control motor M increases. Also, in the relationship between torque and rotation speed, as the torque increases, the rotation speed of the phase control motor M decreases. This relationship between torque and rotation speed approaches the characteristics of maximum performance as the voltage value of the voltage applied to the phase control motor M increases, and deviates from the characteristics of maximum performance as the voltage value of the voltage applied to the phase control motor M decreases.

[0061] In such a characteristic diagram, when a target current value indicated by a wavy line is set, the higher the required torque, the higher the voltage value of the voltage applied to the phase control motor M. On the other hand, the lower the required torque, the lower the voltage value of the voltage applied to the phase control motor M.

[0062] For example, in the constant conversion speed control where the applied voltage is lowered when the rotational speed of the motor is high and the applied voltage is raised when the rotational speed of the motor is low, as shown in (B) of FIG. 6, the consumed current increases when the applied voltage is raised. Also, in the constant voltage control where the applied voltage is constant regardless of the rotational speed of the motor, as shown in (C) of FIG. 6, the consumed current tends to increase according to the rotational speed of the motor. However, by configuring as described above, as shown in (A) of FIG. 6, by raising the applied voltage when the rotational speed of the motor is high and lowering the applied voltage when the rotational speed of the motor is low, it becomes possible to suppress the consumed current lower than in the case of the constant conversion speed control or the constant voltage control.

[0063] 〔Other Embodiments〕 Next, other embodiments of the motor control device 1 will be described.

[0064] In the above embodiment, the voltage value setting unit 13 has been described as raising the voltage value of the voltage applied to the phase control motor M when the torque is a positive value and lowering the voltage value of the voltage applied to the phase control motor M when the torque is a negative value. However, it is also possible to configure the voltage value setting unit 13 so as not to change the voltage value of the voltage applied to the phase control motor M based on the torque.

[0065] In the above embodiment, the electric device has been described as being the electric valve opening / closing timing control device 100. However, the electric device may be, for example, an electric pump, a fan, or the like. Also, it may be a device other than these.

[0066] In the above embodiment, the voltage value setting unit 13 was described as lowering the voltage value of the voltage applied to the phase control motor M immediately before the relative rotation phase of the driving-side rotating body A and the driven-side rotating body B reaches its maximum. However, the voltage value setting unit 13 may be configured not to lower the voltage value of the voltage applied to the phase control motor M even immediately before the relative rotation phase of the driving-side rotating body A and the driven-side rotating body B reaches its maximum.

[0067] 〔Outline of the above embodiment〕 Hereinafter, the outline of the motor control device 1 described above will be described.

[0068] (1) The motor control device 1 is a motor control device 1 that controls a motor M for driving an electric device, and includes a target current information acquisition unit 10 that acquires target current information indicating a target current value of the current flowing through the motor M, an actual current information acquisition unit 11 that acquires actual current information indicating an actual current value of the current actually flowing through the motor M, and a voltage value setting unit 13 that sets a voltage value of the voltage applied to the motor M. The voltage value setting unit 13 lowers the voltage value when the actual current value exceeds the target current value, and raises the voltage value when the actual current value is lower than the target current value.

[0069] According to this configuration, when the load on the motor M increases and the actual current exceeds the target current value, the voltage value of the applied voltage applied to the motor M is lowered to reduce the output of the motor M. When the load on the motor M decreases and the actual current is lower than the target current value, the voltage value of the applied voltage applied to the motor M can be raised to increase the output of the motor M. As a result, it is possible to reduce the power consumption when the load on the motor M increases, and to suppress a decrease in the rotational speed of the motor M when the load on the motor M decreases.

[0070] (2) In the motor control device 1 described in (1), it is further preferable to include a torque information acquisition unit 12 that acquires torque information indicating the torque generated in the drive target driven by the electric device, and the voltage value setting unit 13 raises the voltage value when the torque is a positive value and lowers the voltage value when the torque is a negative value.

[0071] According to this configuration, it is possible to suppress the difference in the rotational speed of the motor M between the case where the torque is a positive value and the case where the torque is a negative value. Therefore, it becomes possible to drive the electric device while keeping the rotational speed of the motor M constant.

[0072] (3) In the motor control device 1 according to (1) or (2), the electric device is an electric valve opening / closing timing control device 100 including a drive-side rotating body A that rotates synchronously with the crankshaft 101 of the engine (internal combustion engine) E around the rotation axis core X, a driven-side rotating body B that is coaxial with the rotation axis core X and is disposed inside the drive-side rotating body A and rotates integrally with the intake camshaft (camshaft) 102 for valve opening / closing of the engine E, and a phase adjustment mechanism C that sets the relative rotational phase of the drive-side rotating body A and the driven-side rotating body B. The phase control motor (motor) M is preferably configured to drive the phase adjustment mechanism C.

[0073] According to this configuration, it is possible to achieve both reduction of power consumption and suppression of a decrease in the displacement speed of the relative rotational phase of the drive-side rotating body A and the driven-side rotating body B when driving the electric valve opening / closing timing control device 100.

[0074] (4) In the motor control device 1 according to (3), it is preferable that the voltage value setting unit 13 lowers the voltage value immediately before the relative rotational phase reaches the maximum.

[0075] Depending on the valve opening / closing timing control device 100, a stopper may be provided to prevent damage due to a collision between the drive-side rotating body A and the driven-side rotating body B when the relative rotational phase reaches the maximum. Therefore, by configuring as described above, even when the relative rotational speed is increased, damage due to a collision can be prevented.

Industrial Applicability

[0076] The technology according to the present disclosure can be used in a motor control device that controls a motor for driving an electric device.

Explanation of Reference Numerals

[0077] 1: Motor control device, 10: Target current information acquisition unit, 11: Actual current information acquisition unit, 12: Torque information acquisition unit, 13: Voltage value setting unit, 101: Crankshaft, 102: Intake camshaft (camshaft), A: Driving-side rotating body, B: Driven-side rotating body, C: Phase adjustment mechanism, E: Engine (internal combustion engine), M: Phase control motor (motor), X: Axis of rotation

Claims

1. A motor control device for controlling a motor that drives an electric device, a target current information acquisition unit that acquires target current information indicating a target current value of a current supplied to the motor, an actual current information acquisition unit that acquires actual current information indicating an actual current value of a current actually flowing through the motor, and a voltage value setting unit that sets a voltage value to be applied to the motor, wherein the voltage value setting unit lowers the voltage value when the actual current value exceeds the target current value, and raises the voltage value when the actual current value is lower than the target current value.

2. further comprising a torque information acquisition unit that acquires torque information indicating torque generated in a drive target driven by the electric device, wherein the voltage value setting unit raises the voltage value when the torque is a positive value, and lowers the voltage value when the torque is a negative value, according to the motor control device of Claim 1.

3. The electric device is an electric valve opening / closing timing control device including a drive-side rotating body that rotates synchronously with a crankshaft of an internal combustion engine about a rotation axis center, a driven-side rotating body that is coaxial with the rotation axis center and is disposed inside the drive-side rotating body and rotates integrally with a camshaft for opening / closing a valve of the internal combustion engine, and a phase adjustment mechanism that sets a relative rotation phase between the drive-side rotating body and the driven-side rotating body, wherein the motor drives the phase adjustment mechanism, according to the motor control device of Claim 1 or 2.

4. wherein the voltage value setting unit lowers the voltage value immediately before the relative rotation phase reaches the maximum, according to the motor control device of Claim 3.

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