JP2009041762A - Operation control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation control device capable of appropriately controlling the residual magnetism of a magnetic fluid. <P>SOLUTION: The operation control device is used to selectively restrict the operation of an operation member which is at least reciprocated or rotated. Specifically, after a magnetic field is increased based on an operation restriction request by the operation member, the operation control device performs control to generate a magnetic field in the direction reverse to that of the magnetic field applied when the magnetic field is increased, so that the magnetic fluid has predetermined viscosity. More specifically, the operation control device performs control with respect to a magnet coil based on a map correlated with a demagnetization ratio indicating a degree of the softening of the magnetic fluid with respect to an electric current applied to the magnet coil and an electricity application time. Thus, the residual magnetism of the magnetic fluid can be appropriately removed for a required minimum time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technical field of an operation control device that selectively restricts the operation of a rotating member that moves back and forth, for example, under a pressing force or rotates under a torque.

  2. Description of the Related Art Conventionally, there has been known an operation control device that determines the position of a member that operates directly, adjusts the relative position, and limits the relative rotation of a relatively rotating member. For example, in Patent Document 1, a magnet plate is disposed at one end of a shaft body by an amount corresponding to an increase in the gap during armature adsorption and inserted into the chamber, and a magnet plate with a different polarity is disposed on the chamber wall surface and the interior of the chamber is magnetized. A clearance adjustment mechanism for an electromagnetic clutch filled with powder is described. In addition, techniques related to the present invention are described in Patent Documents 2 and 3.

Japanese Utility Model Publication No. 62-102035 JP 2002-310197 A Japanese Patent Laid-Open No. 11-22774

  By the way, in the operation control apparatus as described above, a magnetic fluid is used. However, in the techniques described in Patent Documents 1 to 3, the residual magnetism in the magnetic fluid is solidified after the magnetic fluid is solidified. There is no description on how to properly remove.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an operation control device capable of appropriately controlling the residual magnetism of a magnetic fluid.

  In one aspect of the present invention, an operation control device that selectively restricts the operation of at least a reciprocating or rotating operation member presses a friction plate that transmits torque by frictional contact, and constitutes the operation member. And the actuator that applies thrust to the piston, and the fluid is housed in a fluid chamber formed between the piston and the actuator. And a magnetic field control means for controlling the magnetic field generating means for applying a magnetic field to the magnetic fluid, wherein the magnetic field control means increases the magnetic field in response to an operation restriction request of the operating member. After that, a magnetic field in a direction opposite to the magnetic field applied when the magnetic field is increased is generated so that the magnetic fluid has a predetermined viscosity. Performs control with respect to the magnetic field generating means so that.

  The motion control device is used to selectively limit at least the motion of the motion member that reciprocates or rotates. Specifically, the motion control device generates a magnetic field in a direction opposite to that when the magnetic field is increased so that the magnetic fluid has a predetermined viscosity after increasing the magnetic field in response to a motion restriction request of the motion member. Thus, the magnetic field generating means is controlled. Thereby, for example, the residual magnetism of the magnetic fluid can be appropriately removed. In addition, since an AC control device for removing the residual magnetism of the magnetic fluid is not necessary, the cost can be reduced and the mountability can be improved.

  In one mode of the above-described operation control device, the magnetic field generation unit is configured by an electromagnetic coil, and the magnetic field control unit generates the magnetic field in the reverse direction with respect to the current applied to the electromagnetic coil and the energization time. Based on the map associated with the demagnetization factor indicating the degree of softening of the magnetic fluid, the current applied to the electromagnetic coil and the energization time are controlled when the reverse magnetic field is generated. In this aspect, the magnetic field generating means can control the electromagnetic coil so that the magnetic fluid has a predetermined viscosity based on a map of the demagnetization factor using the current applied to the electromagnetic coil and the energization time as variables.

  In another aspect of the operation control apparatus, the magnetic field control unit obtains the current and the energization time from the map such that the energization time is the shortest while the demagnetization factor equal to or higher than a predetermined value is obtained. Then, the electromagnetic coil is controlled. As a result, the residual magnetism of the magnetic fluid can be appropriately removed in the minimum necessary time.

  Preferably, the magnetic field control means sets the current and the energization time so that the energization time is the shortest while the demagnetization factor equal to or greater than the predetermined value is obtained when the friction plate is subjected to wear adjustment. Obtained from the map, the electromagnetic coil is controlled. Thereby, engagement responsiveness can be improved.

  Preferably, when the clutch is disengaged, the magnetic field control means has the shortest energization time when the demagnetization factor equal to or higher than the predetermined value is obtained when the electromagnetic coil is intermittently energized. The current and the energization time are obtained from the map, and the electromagnetic coil is controlled. As a result, the clutch engagement pressure (engagement pressure) can be quickly lowered, and the clutch release response can be improved.

  In another mode of the above operation control device, the magnetic field control unit controls the electromagnetic coil based on an area on the map in which the demagnetization rate of the magnetic fluid can be controlled in a short time. Thereby, the viscosity of the magnetic fluid can be adjusted appropriately. This also eliminates the need for an AC control device, thereby reducing costs and improving mountability.

  Preferably, the magnetic field control means is based on an area on the map in which the demagnetization rate in the magnetic fluid can be controlled in a short time when the electromagnetic coil is intermittently energized when the clutch is released. Then, the electromagnetic coil is controlled. Thereby, the shock at the time of engagement can be suppressed and smooth engagement can be performed.

  Preferably, the magnetic field control means can control the demagnetization rate in the magnetic fluid in a short time after reducing the current flowing through the electromagnetic coil when maintaining the engaged state in the clutch. Based on the area on the map, the electromagnetic coil is controlled. As a result, the current used for the actuator can be appropriately reduced by reducing the clutch engagement pressure, and the loss can be reduced.

  Preferably, in the operation control device, the map is defined based on a current applied to the electromagnetic coil and an energization time when the magnetic field is increased by an operation restriction request of the operation member.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
First, a first embodiment of the present invention will be described.

(overall structure)
FIG. 1 is a diagram schematically showing an operation control apparatus according to an embodiment of the present invention. This figure corresponds to an example of an electromagnetic clutch to which the present invention is applied.

  The actuator 1 is configured to generate thrust by an electromagnet 2 and an armature 3 attracted by the electromagnet 2. The electromagnet 2 has an annular shape as a whole and a yoke 4 having a U-shaped peripheral partial cross section that is open in the axial direction, and an electromagnetic coil (hereinafter referred to as a “main coil”) that generates a magnetic field when energized. 5). The main coil 5 is fitted into the yoke 4. The armature 3 includes a ring-shaped flat plate portion 6 that faces the yoke 4 and a cylinder portion 7 that is integrated with an outer peripheral end of the flat plate portion 6. The cylinder part 7 includes an inner cylinder part 7a and an outer cylinder part 7b having a diameter larger than that. The cylinder part 7 has an annular shape as a whole, and a peripheral part has a hollow shape.

  The cylinder portion 7 is disposed so as to cover at least a part of the outer periphery side of the yoke 4, and a thin plate-like retainer 8 is attached to the tip portion thereof. Another retainer 9 facing this retainer 8 is fixed to a predetermined fixing portion 10 holding the electromagnet 2. A return spring 11 is disposed between the retainers 8 and 9. The return spring 11 is compressed when the armature 3 is attracted and moved forward by the electromagnet 2, and has an elastic force that pushes the armature 3 back to the original initial position when the attraction force (the thrust of the armature 3) by the electromagnet 2 is lost. appear.

  An electromagnet 12 is fixed to a substantially central portion in the axial direction inside the cylinder portion 7. The electromagnet 12 includes a base ring 12a fixed to the outer peripheral surface of the inner cylindrical portion 7a, an electromagnetic coil (hereinafter referred to as “subcoil”) 12b fitted to the outer peripheral side, and a frame member 12c that covers the subcoil 12b. And comprising. A slight gap is opened between the base ring 12a, the subcoil 12b, and the frame member 12c, and this gap forms a flow path for the magnetic fluid 24.

  The first piston 13 is fitted to one side (right side in FIG. 1) sandwiching the electromagnet 12 inside the cylinder portion 7 so as to move back and forth while maintaining a liquid-tight state. Accordingly, a first piston chamber 14 is formed between the electromagnet 12 and the first piston 13. Further, the second piston 15 is fitted on the other side (the left side in FIG. 1) sandwiching the electromagnet 12 inside the cylinder portion 7 so as to move back and forth while maintaining a liquid-tight state. Accordingly, a second piston chamber 16 is formed between the electromagnet 12 and the second piston 15.

  The first piston 13 includes a portion that extends in the axial direction from a portion that fits inside the cylinder portion 7, and that portion approaches the friction plate 18 that constitutes the clutch mechanism 17 that functions as a brake. Opposite. The friction plate 18 includes a brake plate that is spline-fitted to the inner peripheral surface of the casing 19, and brake disks that are spline-fitted to the outer peripheral surface of the brake drum 20 and arranged alternately with respect to the brake plate. By being pressed in the thickness direction (axial direction) by one piston 13, it is configured to frictionally contact each other and transmit torque. In the example shown in FIG. 1, the brake drum 20 is integrated with the sun gear 22 of the planetary gear mechanism 21, and the sun gear 22 is selectively braked. The second piston 15 includes a portion extending in the axial direction (left direction in FIG. 1) from a portion that fits inside the cylinder portion 7, and the portion is provided on a stopper 23 attached to the casing 19. It is comprised so that it may contact | abut.

  A magnetic fluid 24 is sealed inside the piston chambers 14 and 16. The magnetic fluid 24 is, for example, a fluid in which a magnetic powder is mixed in oil, and is a fluid that increases in viscosity, decreases in fluidity, or solidifies in accordance with an applied magnetic field. Note that the control of the current amount and energization time for the main coil 5 and the subcoil 12b described above is based on requests for engagement and release of the clutch mechanism 17 and requests for solidification of the magnetic fluid 24 and requests for releasing the solidification associated with these requests. It is executed by a command signal from the ECU 100 based on it. The control current applied to the subcoil 12b is assumed to be a direct current.

  Here, the basic operation of the above-described apparatus will be described. Specifically, the operation when the control until the clutch mechanism 17 is engaged (hereinafter referred to as “normal control”) will be described.

  The state shown in FIG. 1 is a state in which the main coil 5 is in an off state and no pressing action is performed, and the armature 3 is pushed back to the initial position on the backward side together with the pistons 13 and 15 by the return spring 11. . In this state, the subcoil 12b is also in the OFF state, and therefore, the magnetic fluid 24 is hardly affected by the magnetic field, and the viscosity of the magnetic fluid 24 is low and the fluidity is maintained. Further, the second piston 15 abuts against the stopper 23 and is relatively pushed into the second piston chamber 16. Therefore, since the volume of the second piston chamber 16 is small, most of the magnetic fluid 24 has moved to the inside of the first piston chamber 14. Therefore, the volume of the first piston chamber 14 is large or the amount of the magnetic fluid 24 inside the first piston chamber 14 is large, so that the first piston 13 protrudes relatively large from the armature 3 and the stroke adjustment is performed. It is on the front side in the pressing direction.

  When the determination to start engagement is established and an engagement command is issued in such a state, first, the ECU 100 executes control for increasing the current of the main coil 5. As a result, the armature 3 is attracted by the magnetic force of the main coil 5, and axial thrust is generated. When the suction force acting on the armature 3 becomes larger than the elastic force by the return spring 11, the armature 3 starts to move. When the pistons 13 and 15 are moved together with the armature 3, the first piston 13 comes into contact with the friction plate 18, and the second piston 15 is separated from the stopper 23 and can move to the stopper 23 side. Accordingly, the armature 3 moves forward in a state where the advancement of the first piston 13 is blocked, so that the first piston 13 is relatively pushed back toward the inside of the cylinder 7. Therefore, in this state, there is no pressing force that positively frictionally contacts the friction plate 18. Further, the magnetic fluid 24 in the first piston chamber 14 moves to the second piston chamber 16 through the above-described flow path, and the second piston 15 is pushed out toward the stopper 23 accordingly. Therefore, the protrusion amount of the first piston 13 from the armature 3 or the relative position of both is changed, and the stroke position of the first piston 13 is relatively adjusted in the backward direction.

  Thus, when the armature 3 moves forward to the set position, the ECU 100 performs control to temporarily reduce the current of the main coil 5. Thereby, the thrust by the main coil 5 is temporarily reduced. Next, when the air gap between the armature 3 and the yoke 4 becomes substantially zero, the ECU 100 increases the current of the subcoil 12b. Thereby, when the magnetic field from the subcoil 12b acts on the magnetic fluid 24, the magnetic fluid 24 is solidified or its viscosity increases. Therefore, the magnetic fluid 24 filled in the first piston chamber 14 is sealed in the first piston 13, and the relative movement of the armature 3 and the first piston 13 approaching is limited. Alternatively, the movement of the armature 3 is restricted or restricted while the advance of the first piston 13 is stopped, and as a result, the thrust of the armature 3 is transmitted to the first piston 13. As a result, the first piston 13 presses the friction plates 18 to bring them into frictional contact with each other, and the clutch mechanism 17 is engaged.

(Control method)
Next, a control method performed by the ECU 100 in the first embodiment will be specifically described.

  In the first embodiment, the ECU 100 executes the control for solidifying the magnetic fluid 24 or the control for increasing the viscosity as described above so that the magnetic fluid 24 has a predetermined viscosity. Control is performed so that a magnetic field in the opposite direction to the magnetic field used in the control is generated. That is, the ECU 100 performs a control for solidifying the magnetic fluid 24 or a control for increasing the viscosity, and a current opposite to the current that flows through the subcoil 12b (hereinafter simply referred to as “reverse current”). Control to flow.

  Specifically, the ECU 100 indicates the degree to which the magnetic fluid 24 is softened by flowing the reverse current through the subcoil 12b with respect to the reverse current applied to the subcoil 12b and the energization time (in other words, the magnetic fluid 24 Based on a map associated with a demagnetizing factor (hereinafter referred to as a “demagnetizing factor map”) indicating the degree of viscosity of the sub-coil 12b, the amount of reverse current flowing through the subcoil 12b and energization time are controlled. To do. More specifically, in the first embodiment, the ECU 100 has the shortest energization time while a demagnetizing factor equal to or higher than a predetermined value (for example, a demagnetizing factor that can be considered that residual magnetism has been sufficiently removed) is obtained. The reverse current and the energization time are obtained from the demagnetization factor map, and the sub coil 12b is controlled. By performing the above control, it is possible to remove the residual magnetism of the magnetic fluid 24 in the minimum necessary time. Further, according to the first embodiment, since an AC control device is not required, the cost can be reduced and the mountability can be improved.

  FIG. 2 is a diagram for explaining the basic concept of the control method according to the first embodiment. In FIG. 2, the horizontal axis indicates time, and the vertical axis indicates the current that flows through the subcoil 12 b (hereinafter simply referred to as “subcoil current”). First, as indicated by reference numeral X1, the ECU 100 applies an electric current to the subcoil 12b in order to solidify the magnetic fluid 24 or increase the viscosity. In the following, the subcoil current used at this time is expressed as “I1”, and the energization time is expressed as “T1”. Next, the ECU 100 causes a current as indicated by the symbol X1 to flow through the subcoil 12b, and then causes a reverse current as indicated by the symbol X2 to flow through the subcoil 12b. For example, as described above, in order to remove the residual magnetism of the magnetic fluid 24, a reverse current is passed in this way. Hereinafter, the sub-coil current used when the reverse current is passed is denoted as “I2”, and the energization time is denoted as “T2”.

  FIG. 3 is a diagram illustrating an example of the above-described demagnetization factor map. As shown in FIG. 3, in the demagnetization factor map, the demagnetization factor is associated with the sub-coil current I2 and the energization time T2 described above. In FIG. 3, the higher the demagnetization factor (that is, the lower the viscosity of the magnetic fluid 24), the darker the color. The demagnetization factor map is obtained by measuring in advance.

  In FIG. 3, a region A is a region where the subcoil current I2 is relatively small and the energization time T2 is relatively wide. When the subcoil 12b is energized by the subcoil current I2 and the energization time T2 in the region A, a high demagnetization factor can be obtained. Region B is a region where the subcoil current I2 is small and the energization time T2 is short. When the subcoil 12b is energized by the subcoil current I2 and the energization time T2 in the region B, the demagnetization factor of the magnetic fluid 24 can be greatly changed (that is, the demagnetization factor is increased). The region C is a region where the range of the subcoil current I2 is relatively wide and the energization time T2 is short. When the subcoil 12b is energized by the subcoil current I2 and the energization time T2 in the region C, a high demagnetization factor can be obtained. The region D is a region where the subcoil current I2 is large and the energization time T2 is long. When the subcoil 12b is energized by the subcoil current I2 and the energization time T2 in the region D, the demagnetization rate is relatively low. This is presumably because the magnetic fluid 24 started to magnetize in reverse due to the long energization time T2.

  In the first embodiment, the subcoil 12b is controlled based on the subcoil current I2 in the region C and the energization time T2. This is because when the subcoil 12b is energized by the subcoil current I2 and the energization time T2 in the region C, a high demagnetization rate can be obtained by the short energization time T2, that is, reliable demagnetization is possible in a short time. Because it becomes.

  The demagnetization factor map is defined for each subcoil current I1 and energization time T1 described above. This is because the demagnetization factor map changes depending on the subcoil current I1 and the energization time T1. This is because, for example, the subcoil current I2 at which a high demagnetization rate is obtained and the short time change. Therefore, the ECU 100 described above performs control to flow the reverse current by switching the demagnetization map used according to the sub-coil current I1 and the energization time T1 used before flowing the reverse current.

  FIG. 4 shows an example of a demagnetizing factor map obtained when different subcoil currents I1 are used. FIGS. 4A and 4B show examples of demagnetizing factor maps in which demagnetizing factors are associated with the subcoil current I2 and the energizing time T2, respectively. Specifically, FIG. 4A shows a demagnetization map obtained when “1 (A)” is used as the subcoil current I1, and FIG. 4B shows “0. 5 (A) ”shows a demagnetizing factor map obtained. According to FIG. 4, the subcoil current that was set when a predetermined demagnetization factor was obtained when “1 (A)” was used as the subcoil current I1 and when “0.5 (A)” was used. It can be seen that there is a difference of ΔI2 in I2 (for example, the subcoil current I2 that provides the highest demagnetization factor). Specifically, it can be seen that when the subcoil current I1 is large, the subcoil current I2 to be set to obtain a predetermined demagnetization factor is large.

  Next, the control method for the subcoil 12b based on the demagnetization factor map will be described more specifically. The ECU 100 refers to the demagnetization ratio map, obtains a subcoil current and an energization time that minimize the energization time while obtaining a demagnetization factor of a predetermined value or more, and controls the subcoil 12b. In the following, the predetermined value of the demagnetization factor is expressed as “Dm_max”, and the subcoil current and the energization time that provide the shortest energization time among the demagnetization rates equal to or higher than Dm_max in the demagnetization factor map are “I2_min” and “ Indicated as “T2_min”. Note that the predetermined value of the demagnetizing factor used when obtaining I2_min and T2_min corresponds to, for example, a demagnetizing factor that can be considered that the residual magnetism has been sufficiently removed.

  FIG. 5 is a diagram for specifically explaining how to obtain the sub-coil current I2_min and the energization time T2_min. FIG. 5A shows an example of a demagnetizing factor map in which a demagnetizing factor is associated with the subcoil current I2 and the energization time T2. Further, in FIG. 5A, a part of lattice points in the demagnetization factor map in which a demagnetization factor equal to or higher than Dm_max is indicated by black circles, and a part of lattice points in the demagnetization factor map in which the demagnetization factor is less than Dm_max is indicated by white circles. Show. On the other hand, FIG.5 (b) has shown the figure which observed Fig.5 (a) from upper direction. From FIG. 5, it can be seen that the point P is the point at which the energization time is the shortest among the demagnetization rates equal to or higher than Dm_max. Therefore, the subcoil current and the energization time at the point P are I2_min and T2_min, respectively. Note that the point P obtained in this manner tends to be located in a region C (see FIG. 3) in the demagnetization factor map.

  The ECU 100 controls the subcoil 12b based on the subcoil current I2_min and the energization time T2_min obtained as described above when removing the residual magnetism of the magnetic fluid 24. As a result, the residual magnetism of the magnetic fluid 24 can be removed in a short time.

  ECU 100 stores sub-coil current I2_min and energization time T2_min obtained in advance, and ECU 100 performs control using the stored sub-coil current I2_min and energization time T2_min. Further, the sub-coil current I2_min and the energization time T2_min are obtained for each sub-coil current I1 and the energization time T1 described above and stored in the ECU 100. That is, the ECU 100 stores data in which the sub coil current I2_min and the energization time T2_min are associated with the sub coil current I1 and the energization time T1. This is because the demagnetization rate map and the like change depending on the subcoil current I1 and the energization time T1.

(First control example)
Next, a first control example executed by the ECU 100 in the first embodiment will be described. In the first control example, the ECU 100 reduces the viscosity of the magnetic fluid 24 by being magnetized and increasing in order to remove the influence on the residual magnetism when the clutch mechanism 17 is engaged (at the time of wear adjustment). Control for. Specifically, in the first control example, the ECU 100 performs control (hereinafter referred to as “demagnetization control”) that causes a reverse current to flow to the subcoil 12 b when the clutch mechanism 17 is engaged. More specifically, the ECU 100 executes demagnetization control based on the subcoil current I2_min and the energization time T2_min obtained from the demagnetization factor map described above.

  With reference to FIG. 6, the 1st control example in 1st Embodiment is demonstrated concretely. 6A shows the time change of the hydraulic pressure, FIG. 6B shows the time change of the stroke of the armature 3, and FIG. 6C shows the time change of the subcoil current. In FIG. 6, the solid line indicates an example of a result when the control according to the first control example is performed, and the broken line indicates an example of a result when the control according to the first comparative example in the first embodiment is performed. Is shown. Note that the control according to the first control example in the first embodiment corresponds to control in which a reverse current is supplied to the subcoil 12b according to the demagnetization map described above, and corresponds to the first comparative example in the first embodiment. Such control corresponds to control in which a reverse current is supplied to the subcoil 12b without considering the demagnetization map described above.

  In this case, an engagement instruction (clutch engagement instruction) for the clutch mechanism 17 is issued at time t11. Thereafter, when a predetermined time has elapsed from time t11 (including when the ignition switch of the engine is turned on, etc.), control is performed such that a reverse current is supplied to the subcoil 12b. Specifically, as shown in FIG. 6C, a reverse current as indicated by a solid line 70 is applied in the first control example, and a reverse current as indicated by a broken line 71 is applied in the first comparative example. Energized. Specifically, in the first control example, a reverse current corresponding to the subcoil current I2_min and the energization time T2_min obtained from the demagnetization factor map is energized. In this case, it can be seen that the reverse current in the first control example is shorter in energization time than the reverse current in the first comparative example.

  In this way, after the reverse current is supplied to the subcoil 12b, the wear adjustment of the friction plate 18 in the clutch mechanism 17 is performed. In this case, as indicated by the white arrow 73 in FIG. 6A, according to the control according to the first control example, the hydraulic pressure rapidly increases as compared with the control according to the first comparative example. It turns out that it is suppressed. Therefore, according to the control according to the first control example, it is possible to suppress the generation of the transmission torque generated in the first piston 13 and the friction plate 18, that is, it is possible to prevent the engagement shock. Furthermore, the surge pressure when the first piston 13 contacts the friction plate 18 is reduced, and leakage of the magnetic fluid 24 can be suppressed.

  Next, at time t12, as shown in FIG. 6C, control for energizing the subcoil 12b is performed in order to solidify the magnetic fluid 24 or increase the viscosity. Here, as shown by the white arrow 74 in FIG. 6A, according to the control according to the first control example, an appropriate hydraulic pressure is obtained as compared with the control according to the first comparative example. You can see that Therefore, according to the control according to the first control example, it can be said that the piston stroke at the time of wear adjustment becomes faster and the wear adjustment time can be shortened, so that the engagement response is improved. This is considered to be because the residual magnetism of the magnetic fluid 24 was appropriately removed by performing demagnetization control using a reverse current as indicated by the solid line 70 in FIG. 6C.

  FIG. 7 is a flowchart illustrating processing performed in the first control example in the first embodiment. This process is executed by the ECU 100.

  First, in step S101, the ECU 100 issues an engagement instruction (clutch engagement instruction) to the clutch mechanism 17. Then, the process proceeds to step S102. In step S102, the ECU 100 executes the demagnetization control described above. Specifically, ECU 100 allows a reverse current to flow through sub-coil 12b when a predetermined time has elapsed since the clutch engagement instruction was issued (including when the engine ignition switch is turned on). Execute control. Specifically, the ECU 100 executes control for flowing a reverse current to the subcoil 12b based on the subcoil current I2_min and the energization time T2_min obtained from the demagnetization factor map. When the above process ends, the process exits the flow.

  According to the control according to the first control example in the first embodiment, the residual magnetism of the magnetic fluid 24 can be appropriately removed, and the engagement response can be improved.

(Second control example)
Next, a second control example executed by the ECU 100 in the first embodiment will be described. In the second control example, the ECU 100 performs control to intermittently energize the subcoil 12b (hereinafter referred to as “intermittent energization control”) when the clutch mechanism 17 is released. Specifically, when the clutch mechanism 17 is released, the ECU 100 reverses the pulse current in one direction (hereinafter referred to as “positive pulse current”) and the positive pulse current with respect to the subcoil 12b. Intermittent current control is performed in which a pulse current (hereinafter referred to as “reverse pulse current”) is alternately flowed. The reverse pulse current corresponds to the reverse current described above. The intermittent energization control is performed in order to appropriately control the lowering speed of the engagement pressure of the clutch mechanism 17. Note that the ECU 100 performs intermittent energization control for supplying a reverse pulse current to the subcoil 12b based on the subcoil current I2_min and the energization time T2_min obtained from the demagnetization factor map described above.

  With reference to FIG. 8, the 2nd example of control in 1st Embodiment is demonstrated concretely. FIG. 8A shows the time change of the current (hereinafter referred to as “main coil current”) flowing through the main coil 5, FIG. 8B shows the time change of the subcoil current, and FIG. ) Shows the change over time of the engagement pressure (engagement pressure) of the clutch mechanism 17. In FIG. 8, the solid line indicates an example of the result when the control according to the second control example in the first embodiment is performed, and the broken line indicates the control according to the second comparative example in the first embodiment. An example of the result of the case is shown. The control according to the second control example in the first embodiment corresponds to intermittent energization control in which a reverse pulse current is supplied to the subcoil 12b in accordance with the demagnetization factor map described above, and the second comparison in the first embodiment. The control according to the example corresponds to intermittent energization control in which a reverse pulse current is energized to the subcoil 12b without considering the demagnetization factor map described above.

  In this case, the release of the clutch mechanism 17 is started at time t21. At this time, energization of the main coil 5 is stopped (see FIG. 8A), and intermittent energization control is executed for the subcoil 12b (see FIG. 8B). Specifically, as shown in FIG. 8B, intermittent energization control as shown by a solid line 75 is executed in the second control example, and intermittent energization control as shown by a broken line 76 is executed in the second comparative example. Executed. Specifically, in the second control example, intermittent energization control is executed using a reverse coil current corresponding to the subcoil current I2_min and the energization time T2_min obtained from the demagnetization factor map. In this case, it can be seen that the reverse pulse current in the second control example is shorter in energization time than the reverse pulse current in the second comparative example.

  When such intermittent energization control is executed, the pressure in the first piston chamber 14 changes as indicated by a solid line 77 and a broken line 78 in FIG. The pressure in the first piston chamber 14 corresponds to the engagement pressure (engagement pressure) of the clutch mechanism 17. From this, it can be seen that according to the control according to the second control example, the engagement pressure of the clutch mechanism 17 is rapidly reduced as compared with the control according to the second comparative example. Therefore, according to the control according to the second control example, it can be said that the release response in the clutch mechanism 17 is improved as compared with the control according to the second comparative example. When the control according to the second comparative example is executed, the lowering speed of the clutch engagement pressure is relatively slow because the demagnetization of the magnetic fluid 24 becomes insufficient because the energization time in the reverse pulse current is long, and the hydraulic pressure is This is probably because it did not fall appropriately.

  FIG. 9 is a flowchart showing processing performed in the second control example in the first embodiment. This process is repeatedly executed by the ECU 100.

  First, in step S <b> 201, the ECU 100 determines whether a release execution condition for the clutch mechanism 17 is satisfied. If the release execution condition is satisfied (step S201; Yes), the process proceeds to step S202. If the release execution condition is not satisfied (step S201; No), the process exits the flow. In step S202, the ECU 100 stops energization of the main coil 5 and performs intermittent energization control on the subcoil 12b in order to open the clutch mechanism 17. Specifically, the ECU 100 executes control for alternately flowing a positive pulse current and a reverse pulse current to the subcoil 12b. Specifically, the ECU 100 executes intermittent energization control for supplying a reverse pulse current to the subcoil 12b based on the subcoil current I2_min and the energization time T2_min obtained from the demagnetization factor map described above. Then, the process proceeds to step S203.

  In step S203, the ECU 100 determines whether or not the release of the clutch mechanism 17 has been completed. For example, the ECU 100 determines whether or not the release of the clutch mechanism 17 has been completed based on the fastening pressure of the clutch mechanism 17. When the opening is completed (step S203; Yes), the process proceeds to step S204. When the opening is not completed (step S203; No), the process exits the flow. In step S204, the ECU 100 stops energizing the subcoil 12b because the release of the clutch mechanism 17 has been completed. Then, the process exits the flow.

  According to the control according to the second control example in the first embodiment described above, the engagement pressure of the clutch mechanism 17 can be quickly lowered, and the release response of the clutch mechanism 17 can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  Also in the second embodiment, the ECU 100 controls the amount of reverse current to be supplied to the subcoil 12b and the energization time based on the demagnetization factor map as in the first embodiment described above. However, in the first embodiment, the reverse current and the energization time that provide the shortest energization time among the demagnetization ratios greater than or equal to the predetermined value are obtained from the demagnetization factor map and the subcoil 12b is controlled. In the second embodiment, the ECU 100 controls the subcoil 12b based on a region on the demagnetization factor map in which the demagnetization factor in the magnetic fluid 24 can be controlled in a short time. Specifically, in the first embodiment, the control on the subcoil 12b is performed based on the region C shown in FIG. 3, but in the second embodiment, the control on the subcoil 12b is performed based on the region B shown in FIG. . That is, in the second embodiment, the ECU 100 controls the subcoil 12b according to a region where the viscosity of the magnetic fluid 24 can be changed in a short time. The purpose of this is to remove the residual magnetism of the magnetic fluid 24 reliably in the first embodiment, whereas in the second embodiment, by leaving the viscosity of the magnetic fluid 24 to some extent, This is because the purpose is to use this viscosity. Note that the region B (see FIG. 3) on the demagnetization factor map used in the second embodiment is defined as a region where the demagnetization factor is not more than a specified value and the energization time is not more than the specified value.

  According to the second embodiment described above, the viscosity of the magnetic fluid 24 can be appropriately controlled, and a shock can be effectively suppressed during engagement and the like. Further, according to the second embodiment, since an AC control device is not necessary, the cost can be reduced and the mountability can be improved.

(First control example)
Next, a first control example executed by the ECU 100 in the second embodiment will be described. In the first control example, when the clutch mechanism 17 is engaged, the ECU 100 performs the intermittent energization control as shown in the second control example of the first embodiment described above on the subcoil 12b. That is, the ECU 100 executes control for alternately flowing a positive pulse current and a reverse pulse current to the subcoil 12b when the clutch mechanism 17 is engaged. More specifically, the ECU 100 executes intermittent energization control for supplying a reverse pulse current to the subcoil 12b based on the subcoil current I2 and the energization time T2 in the region B in the demagnetization factor map described above. The intermittent energization control is executed in order to suppress the shock at the time of engagement by gradually increasing the transmission torque.

  With reference to FIG. 10, the 1st example of control in 2nd Embodiment is demonstrated concretely. FIG. 10A shows an example of a result when the control according to the first control example in the second embodiment is performed, and FIG. 10B shows the control according to the first comparative example in the second embodiment. An example of the result of performing is shown. Specifically, in the control according to the first control example in the second embodiment, a reverse pulse current is applied to the subcoil 12b based on the subcoil current I2 and the energization time T2 in the region B in the demagnetization factor map described above. The control according to the first comparative example in the second embodiment corresponds to the intermittent energization control in which the reverse pulse current is energized to the subcoil 12b without considering the demagnetization map described above. . 10 (a) and 10 (b), respectively, the time change of the main coil current is shown in the upper stage, the time change of the sub coil current is shown in the middle stage, and the engagement pressure (engagement pressure) of the clutch mechanism 17 is shown in the lower stage. ).

  In this case, engagement of the clutch mechanism 17 is started at time t31. At this time, energization to the main coil 5 is started. Thereafter, intermittent energization control is performed on the subcoil 12b. Specifically, in the first control example, intermittent energization control is performed using a reverse pulse current as indicated by reference numeral 81 in FIG. 10A, and in the first comparative example, in FIG. 10B. Intermittent energization control is performed using a reverse pulse current as indicated by reference numeral 82. Specifically, in the first control example, intermittent energization control is executed using the sub-coil current I2 in the region B in the demagnetization factor map and the reverse pulse current corresponding to the energization time T2. In this case, it can be seen that the reverse pulse current in the first control example has a smaller amount of current than the reverse pulse current in the first comparative example.

  When such intermittent energization control is executed, the pressure in the first piston chamber 14 changes as indicated by a solid line 83 in FIG. 10A and a solid line 84 in FIG. The pressure in the first piston chamber 14 corresponds to the engagement pressure of the clutch mechanism 17. From this, it can be seen that according to the control according to the first control example, the engagement pressure of the clutch mechanism 17 is gradually increased as compared with the control according to the first comparative example. In other words, it can be seen that the engagement pressure of the clutch mechanism 17 gradually increases. Therefore, according to the control according to the first control example, it can be said that the shock at the time of engagement is suppressed as compared with the control according to the first comparative example. It should be noted that the fastening pressure is gently increased by the control according to the first control example as described above because the control of the subcoil 12b is performed based on the region B in the demagnetization factor map. This is probably because the viscosity was adjusted appropriately.

  FIG. 11 is a flowchart showing processing performed in the first control example in the second embodiment. This process is repeatedly executed by the ECU 100.

  First, in step S301, the ECU 100 determines whether an engagement execution condition for the clutch mechanism 17 is satisfied. If the engagement execution condition is satisfied (step S301; Yes), the process proceeds to step S302. If the engagement execution condition is not satisfied (step S301; No), the process exits the flow. In step S302, the ECU 100 starts energization of the main coil 5 and performs intermittent energization control on the subcoil 12b in order to engage the clutch mechanism 17. Specifically, the ECU 100 executes control for alternately flowing a positive pulse current and a reverse pulse current to the subcoil 12b. Specifically, the ECU 100 executes intermittent energization control in which a reverse pulse current is supplied to the subcoil 12b based on the subcoil current I2 and the energization time T2 in the region B in the demagnetization factor map described above. Then, the process proceeds to step S303.

  In step S303, the ECU 100 determines whether or not the engagement of the clutch mechanism 17 has been completed. For example, the ECU 100 determines whether or not the engagement of the clutch mechanism 17 has been completed based on the fastening pressure of the clutch mechanism 17. When the engagement is completed (step S303; Yes), the process proceeds to step S304. When the engagement is not completed (step S303; No), the process exits the flow. In step S304, since the engagement of the clutch mechanism 17 has been completed, the ECU 100 stops energizing the subcoil 12b. Then, the process exits the flow.

  According to the control according to the first control example in the second embodiment described above, it is possible to suppress a shock at the time of engagement and perform smooth engagement.

(Second control example)
Next, a second control example executed by the ECU 100 in the second embodiment will be described. In the second control example, the ECU 100 performs control for maintaining the engagement state in the clutch mechanism 17 (that is, holding pressure) after the engagement of the clutch mechanism 17 is completed as described above. Specifically, the ECU 100 executes control for lowering the viscosity of the magnetic fluid 24 to some extent in order to maintain the engaged state with the engagement pressure (engagement pressure) of the clutch mechanism 17 lowered to some extent. In this case, the ECU 100 executes control for energizing the reverse current to the subcoil 12b after the engagement is completed. Specifically, the ECU 100 executes control for energizing a reverse current to the subcoil 12b based on the subcoil current I2 and the energization time T2 in the region B in the demagnetization factor map described above. By performing such control, the fastening pressure can be reduced appropriately, and the main coil current can be reduced. Therefore, loss due to the main coil current can be reduced.

  With reference to FIG. 12, the 2nd example of control in 2nd Embodiment is demonstrated concretely. 12A shows the clutch engagement flag, FIG. 12B shows the time change of the subcoil current, and FIG. 12C shows the time of the engagement pressure (engagement pressure) of the clutch mechanism 17. FIG. 12D shows the change over time of the main coil current. In this case, at the time t41, the engagement of the clutch mechanism 17 ends, and at the same time, a clutch engagement flag for maintaining the engagement state in the clutch mechanism 17 is set. Thereafter, at time t42, the subcoil current is decreased. Thereby, since the magnetic field which acts on the magnetic fluid 24 falls, as shown by the code | symbol 85 in FIG. 12, the fastening pressure of the clutch mechanism 17 falls. For example, the fastening pressure is reduced to about “0.8 (MPa)”.

  If the sub-coil current is reduced as described above, it is held at the fastening pressure as indicated by reference numeral 85. In order to release this, at time t43, it is indicated by reference numeral 86 in FIG. 12 (b). Such reverse current is applied to the subcoil 12b. Specifically, a reverse current corresponding to the subcoil current I2 and the energization time T2 in the region B in the demagnetization factor map is energized to the subcoil 12b. Thereby, since the viscosity of the magnetic fluid 24 is appropriately reduced, the fastening pressure of the clutch mechanism 17 is further reduced as shown in FIG. Since the main coil current can be reduced by reducing the fastening pressure in this way, the main coil current is reduced as indicated by reference numeral 87 in FIG. Thereby, it becomes possible to reduce the loss due to the main coil current. By the above control, as indicated by reference numeral 88 in FIG. 12C, it is possible to maintain the pressure at, for example, about “0.4 (MPa)” due to a decrease in transmission torque or the like.

  FIG. 13 is a flowchart illustrating processing performed in the second control example according to the second embodiment. This process is repeatedly executed by the ECU 100.

  First, in step S401, the ECU 100 determines whether or not the engagement of the clutch mechanism 17 has ended. When the engagement of the clutch mechanism 17 has been completed (step S401; Yes), the process proceeds to step S402. On the other hand, when the engagement of the clutch mechanism 17 has not ended (step S401; No), the process proceeds to step S404. In this case, the ECU 100 executes normal control until the clutch mechanism 17 as described above is engaged (step S404). Then, the process exits the flow.

  In step S402, the ECU 100 reads the map. This map is a map showing the pressure holding characteristic of the magnetic fluid 24 once the viscosity is increased. The pressure applied to the magnetic fluid 24 (corresponding to the engagement pressure of the clutch mechanism 17), the subcoil current, and the temperature of the magnetic fluid 24. It is a map which shows the pressure holding time of the pressure according to each. Then, the process proceeds to step S403.

  In step S403, the ECU 100 controls the sub-coil 12b and the main coil 5 based on the engagement pressure and the pressure holding time of the clutch mechanism 17 obtained from the map in step S402. Specifically, the ECU 100 performs control for energizing the reverse current to the subcoil 12b after performing control for temporarily reducing the subcoil current. In this case, the ECU 100 executes control for energizing a reverse current to the subcoil 12b based on the subcoil current I2 and the energization time T2 in the region B in the demagnetization factor map described above. Further, the ECU 100 performs control to reduce the main coil current. When the above process ends, the process exits the flow.

  According to the control according to the second control example in the second embodiment described above, the main coil current can be appropriately reduced by reducing the fastening pressure, and the loss due to the main coil current can be reduced. Become.

[Modification]
Here, another example of the operation control apparatus according to the present invention will be described. FIG. 14 schematically shows an operation control apparatus according to a modification of the present invention. The motion control device shown here is mounted on a vehicle or the like, maintains a thrust force that pushes an object to be pressed such as the friction plate 30 by using the pressure retention characteristic of the magnetic fluid, and is biased by a thrust generating means such as a motor 41. It is configured so that it can be released.

  In FIG. 14, a pressure holding mechanism 31 facing the friction plate 30 is arranged. The pressure-holding mechanism 31 includes a cylinder 32 and a first piston 33 and a second piston 34 that are housed on both end sides thereof so as to be movable back and forth. In addition, a partition wall 35 is formed at a substantially central portion in the axial direction inside the cylinder 32, and an oil passage 38 through which the left and right oil chambers 36 and 37 communicate is formed through the partition wall 35. Yes. And the magnetic fluid 39 is filled so that these oil chambers 36 and 37 and the oil path 38 may be filled. Further, an electromagnetic coil 40 that generates a magnetic field that increases the viscosity of the magnetic fluid 39 is provided in or near the oil passage 38. Control of the current and energization time of the electromagnetic coil 40 (that is, control of the magnetic field) is performed by an ECU (not shown).

  The first piston 33 is disposed so that the tip portion thereof is opposed to the friction plate 30. The second piston 34 is disposed on the opposite side of the first piston 33 and is configured to apply a thrust (force in the axial direction for pushing the friction plate 30) to the second piston 34. As a mechanism for generating the thrust, a screw mechanism and a motor 41 for rotating the screw mechanism are provided. The screw mechanism and the motor 41 correspond to an actuator. The screw mechanism includes a ball screw shaft 42 as an example of a screw shaft and a nut 43 screwed into the ball screw shaft 42, and the ball screw shaft 42 is the motor 41. And is configured to be rotated by a motor 41. A second piston 34 is connected to the nut 43. The motor 41 is controlled by the ECU.

  When applying a load to the friction plate 30, first, the current to the electromagnetic coil 40 is cut off to reduce the viscosity of the magnetic fluid 39, and in this state, the motor 41 is driven to rotate the ball screw shaft 42. The nut 43 is advanced in the right direction in FIG. As a result, the second piston 34 moves together with the nut 43 and is pushed into the cylinder 32 so that the magnetic fluid 39 in the oil chamber 37 on the left side in FIG. 14 passes through the oil passage 38 and the oil on the right side in FIG. It will move to the chamber 36. Therefore, the first piston 33 moves forward toward the friction plate 30 and presses it. In this way, the thrust by the screw mechanism and the motor 41 acts on the friction plate 30 via the magnetic fluid 39.

  This operation control device is configured to maintain the load or pressing force (engagement force in the case of a friction clutch or friction brake) applied to the friction plate 30 by the pressure holding state of the magnetic fluid 39 as described above. . That is, after the thrust is generated by the screw mechanism and the motor 41 until the friction plate 30 is pressed with a predetermined load, the electromagnetic coil 40 is first energized to generate a magnetic field in the oil passage 38. The current is variably small in a current range in which the viscosity of the magnetic fluid 39 in the oil passage 38 becomes a viscosity that does not flow through the oil passage 38.

  By passing an electric current in this way to the electromagnetic coil 40, the viscosity of the magnetic fluid 39 is increased or substantially solidified at least in the oil passage 38, so that the magnetic material moved to the oil chamber 36 on the right side of FIG. The fluid 39 is confined in the oil chamber 36. Therefore, the reaction force that presses the friction plate 30 is received by the fixed cylinder 32 via the first piston 33 and the magnetic fluid 39. Therefore, even if the driving of the motor 41 is stopped and the thrust by the screw mechanism and the motor 41 is eliminated, the load for pressing the friction plate 30 can be held.

  The above-described control can also be executed for the operation control apparatus described above. That is, after executing the control for solidifying the magnetic fluid 24 or the control for increasing the viscosity, the control is performed so that the reverse current is supplied to the electromagnetic coil 40 so that the magnetic fluid 24 has a predetermined viscosity. It can be carried out. Specifically, control of the electromagnetic coil 40 can be performed based on a demagnetization factor map in which the demagnetization factor is associated with the reverse current applied to the electromagnetic coil 40 and the energization time.

It is the figure which showed typically the operation | movement control apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the basic concept of the control method which concerns on 1st Embodiment. It is a figure which shows an example of a demagnetizing factor map. The example of the demagnetization factor map obtained when different subcoil current I1 is used is shown. It is a figure for demonstrating concretely how to obtain sub coil current I2_min and energization time T2_min. It is a figure for demonstrating the 1st example of control in 1st Embodiment. It is a flowchart which shows the process performed in the 1st control example in 1st Embodiment. It is a figure for demonstrating the 2nd control example in 1st Embodiment. It is a flowchart which shows the process performed in the 2nd control example in 1st Embodiment. It is a figure for demonstrating the 1st example of control in 2nd Embodiment. It is a flowchart which shows the process performed in the 1st control example in 2nd Embodiment. It is a figure for demonstrating the 2nd control example in 2nd Embodiment. It is a flowchart which shows the process performed in the 2nd control example in 2nd Embodiment. It is the figure which showed typically the operation | movement control apparatus which concerns on the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 2, 12 Electromagnet 3 Armature 5 Main coil 11 Return spring 12b Subcoil 13 1st piston 14 2nd piston 17 Clutch mechanism 18 Friction plate 24, 39 Magnetic fluid 100 ECU

Claims (9)

An operation control device that selectively restricts the operation of at least a reciprocating or rotating operation member;
A friction plate that presses a friction plate that transmits torque by frictional contact;
An actuator for applying thrust to the piston;
A magnetic fluid that is housed in a fluid chamber formed between the piston and the actuator and restricts the operation of the operating member by increasing the viscosity by increasing the acting magnetic field; and
Magnetic field control means for controlling the magnetic field generating means for applying a magnetic field to the magnetic fluid,
The magnetic field control means increases the magnetic field in response to an operation restriction request of the operating member, and then reverses the magnetic field applied when the magnetic field is increased so that the magnetic fluid has a predetermined viscosity. An operation control apparatus that controls the magnetic field generation means so that the above is generated. The magnetic field generating means is composed of an electromagnetic coil,
The magnetic field control means is based on a map in which a demagnetizing factor indicating a degree to which the magnetic fluid has been softened by generating the magnetic field in the reverse direction is associated with the current applied to the electromagnetic coil and the energization time. The operation control device according to claim 1, wherein when the magnetic field in the reverse direction is generated, the current applied to the electromagnetic coil and the energization time are controlled.   The magnetic field control means obtains, from the map, the current and the energization time that make the energization time the shortest while the demagnetization factor of a predetermined value or more is obtained, and controls the electromagnetic coil. The operation control device according to claim 2.   The magnetic field control means obtains the current and the energization time from the map so that the energization time is the shortest while the demagnetization factor equal to or higher than the predetermined value is obtained when the friction plate is subjected to wear adjustment. The operation control device according to claim 3, wherein control is performed on the electromagnetic coil.   When the electromagnetic coil is intermittently energized when the clutch is disengaged, the magnetic field control means is configured to reduce the energization time that is the shortest among the demagnetization ratios greater than or equal to the predetermined value, and the current The operation control apparatus according to claim 3, wherein an energization time is obtained from the map, and the electromagnetic coil is controlled.   The motion control apparatus according to claim 2, wherein the magnetic field control unit controls the electromagnetic coil based on an area on the map in which the demagnetization rate of the magnetic fluid can be controlled in a short time. .   When the electromagnetic coil is intermittently energized when the clutch is disengaged, the magnetic field control means is based on the area on the map where the demagnetization rate of the magnetic fluid can be controlled in a short time. The operation control apparatus according to claim 6, wherein control is performed on the coil.   The magnetic field control means is based on an area on the map in which the demagnetization rate in the magnetic fluid can be controlled in a short time after the current flowing through the electromagnetic coil is reduced when maintaining the engaged state in the clutch. The operation control apparatus according to claim 6, wherein control is performed on the electromagnetic coil.   9. The map according to claim 2, wherein the map is defined based on a current applied to the electromagnetic coil and an energization time when the magnetic field is increased by an operation restriction request of the operating member. The operation control device according to the item.