JP6448341B2 - Active vibration isolator - Google Patents

Description

  The present invention relates to an active vibration isolator, and more particularly to an active vibration isolator capable of securing a vibration isolating performance.

  An elastic body that receives vibration of a vibrating body mounted on a vehicle, a liquid chamber in which the elastic body forms at least a part of a wall surface, a movable member that changes the volume of the liquid chamber, and an actuator that drives the movable member with electromagnetic force Is known (for example, Patent Document 1). In the technique disclosed in Patent Document 1, the vibration of the vibrating body can be damped by driving (vibrating) the movable member by passing a current through the actuator.

Japanese Patent No. 5473869

  However, in the above-described conventional technique, when the vibrating body vibrates and the elastic body is deformed, and the internal pressure of the liquid chamber rises and the movable member moves to change the volume of the liquid chamber, a preset damping force, etc. May not be obtained, and the vibration-proof performance may be reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an active vibration isolator capable of ensuring vibration isolation performance.

Means for Solving the Problems and Effects of the Invention

  In order to achieve this object, according to the active vibration isolator of claim 1, at least a part of the wall surface of the liquid chamber is constituted by the elastic body that receives the vibration of the vibration body mounted on the vehicle, and the actuator includes The movable member is driven by electromagnetic force, and the volume of the liquid chamber is changed to suppress vibration. The actuator generates a reaction force against the thrust generated in the movable member by the internal pressure of the liquid chamber changed by the deformation of the elastic body by the reaction force generation means. Thereby, a movement of a movable member when the internal pressure of a liquid chamber changes can be suppressed. As a result, a change in volume of the liquid chamber due to the displacement of the movable member can be suppressed, so that a preset damping force or the like can be obtained, and there is an effect that vibration-proof performance can be secured.

Actuators comprises a coil exciting current for driving the movable member is input, the current flowing through the coil by the movable member is moved by thrust (induced current) is detected by the current detecting means. When a current is detected by the current detection means, a current is passed through the coil by the restriction means, and the movement of the movable member is restricted. Since the movable member by a thrust possible to limit the movable movable member in a short time after the movement, there is an effect capable of suppressing the decrease in vibration damping performance due to the delay of response.

According to the active vibration isolating apparatus of the second aspect , the information on the driving state of the vehicle is acquired by the information acquisition unit, and the driving state of the vehicle acquired by the information acquisition unit is determined by the driving state determination unit It is determined whether the vehicle is in an operating state. As a result of the determination, the reaction force generating means is executed when the driving state of the vehicle is a constant speed traveling state. Therefore, in addition to the effect of the first aspect, there is an effect that it is possible to ensure the anti-vibration performance when the vehicle is running at a constant speed.

It is an axial sectional view of an active vibration isolator in an embodiment of the present invention. It is a schematic diagram of a movable member. It is the block diagram which showed the electrical structure of the active vibration isolator. It is a flowchart of ACM processing. It is a flowchart of a restraint process. It is a flowchart of a movable process.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, the structure of the active vibration isolator 10 will be described with reference to FIG. FIG. 1 is an axial sectional view of an active vibration isolator 10 according to an embodiment of the present invention, and FIG. 2 is a schematic view of a movable member. FIG. 1 illustrates a state before the engine is supported (that is, a state before the weight of the engine is loaded).

  The active vibration isolator 10 is a vibration isolator for supporting and fixing an automobile engine (vibrating body, not shown) and preventing the engine vibration from being transmitted to a vehicle body frame (not shown). As shown in FIG. 1, the first fixture 11 attached to the engine side, the cylindrical second fixture 12 attached to the vehicle body frame side below the engine, and a rubber-like elastic body are connected. A liquid chamber 17 is formed between the anti-vibration base 15 and the second attachment 12 and the anti-vibration base 15, and a diaphragm 18 made of a rubber-like elastic body is connected to the diaphragm 18. An actuator 40 having a shaft 42 and disposed on the opposite side of the liquid chamber 17 across the diaphragm 18, and a piston that is displaced in the axial direction by a drive shaft 42 of the actuator 40 With product 30, and a partition plate 19 having an insertion hole 20 of the piston member 30 is inserted.

  The first fixture 11 is formed in a substantially cylindrical shape from a metal material such as an aluminum alloy, and a hole portion in which a female screw is formed on the inner peripheral surface is recessed in the upper end surface. The second fixture 12 includes a cylindrical fitting 13 in which the vibration-proof base 15 is vulcanized and a bottom fitting 14 fixed to the lower portion of the cylindrical fitting 13 by caulking. The cylindrical metal fitting 13 is formed in a cylindrical shape having an opening extending upward, and the bottom metal fitting 14 is formed in a cup shape having a bottom portion, respectively, from a steel material or the like. A mounting bolt projects from the bottom of the bottom metal fitting 14.

  The anti-vibration base 15 (elastic body) is formed in a truncated cone shape from a rubber-like elastic body, and is vulcanized and bonded between the lower surface side of the first fixture 11 and the upper end opening of the cylindrical fitting 13. A rubber film 16 covering the inner peripheral surface of the cylindrical metal fitting 13 is connected to the lower end portion of the vibration isolating base 15, and the outer peripheral edge of the partition plate 19 is in close contact with the rubber film 16, thereby An orifice 21 is formed between the rubber film 16.

  The diaphragm 18 is formed as a rubber film bent in a bellows shape from a rubber-like elastic body. The outer periphery of the diaphragm 18 is vulcanized and bonded to the annular mounting plate 23 as viewed from above, and the inner periphery is added to the shaft-shaped shaft member 44. Sulfur bonded. The shaft-like member 44 has a projecting portion 24 that projects in a flange shape outward in the radial direction, and is integrally formed with the diaphragm 18 and vulcanized and bonded to the outer peripheral surface. The diaphragm 18 is attached to the second fixture 12 by the attachment plate 23 being clamped and fixed together with the cylindrical fitting 13 by the bottom fitting 14. As a result, a liquid chamber 17 is formed between the upper surface side of the diaphragm 18 and the lower surface side of the vibration isolation base 15. The liquid chamber 17 is filled with an antifreeze liquid (not shown) such as ethylene glycol.

  The partition plate 19 is a member formed in a disk shape from a resin material. Since the partition plate 19 is disposed between the vibration isolation base 15 and the diaphragm 18, the liquid chamber 17 is divided into the first liquid chamber 17 a on the vibration isolation base 15 side and the second liquid chamber 17 b on the diaphragm 18 side. Divided into chambers. The partition plate 19 includes an insertion hole 20 that is drilled along the axis O direction. The piston member 30 is inserted through the insertion hole 20, and the piston member 30 forms a part of a partition wall (wall surface) that partitions the first liquid chamber 17a and the second liquid chamber 17b. Further, the partition plate 19 is held between the mounting plate 23 of the diaphragm 18 and the step portion formed on the film portion 16 of the vibration isolation base 15.

  The partition plate 19 is formed with an orifice forming portion 22 having a U-shaped cross section opened outward in the radial direction on the outer peripheral side, and the diaphragm 18 on the inner peripheral side (axial center O side) of the orifice forming portion 22. And the space opened below for accommodating the piston member 30 is formed. The orifice forming part 22 forms an orifice 21 having a substantially rectangular cross section by being in close contact with the rubber film 16 covering the inner periphery of the cylindrical fitting 13. The orifice forming part 22 includes a notch part (not shown) formed in the upper wall part of the orifice forming part 22 and an opening part (not shown) formed in the body part of the orifice forming part 22. And a vertical wall (not shown) connecting the upper and lower wall portions and the body portion of the orifice forming portion 22. The orifice 21 is divided in the circumferential direction by a vertical wall, communicated with the first liquid chamber 17a through a notch, and communicated with the second liquid chamber 17b through an opening. That is, in the present embodiment, the orifice 21 is formed as an orifice channel having a channel length of about a half circumference from the notch to the opening.

  The piston member 30 (a part of the movable member) is a member formed in a substantially cylindrical shape from a rubber-like elastic body, and is fixed to the tip end of the shaft-like member 44 with a screw 33. As for the piston member 30, the overhang | projection part 31 which protrudes toward radial direction outward is formed in the outer peripheral surface. The piston member 30 and the shaft-like member 44 are arranged in a vertical posture along the axis O of the second fixture 12 (in the present embodiment, coaxially). The piston member 30 is vibrated and displaced in the direction of the axis O in the liquid chamber 17 by transmitting the driving force of the actuator 40 via the driving shaft 42. Thereby, the volume of the liquid chamber 17 is changed, and the hydraulic pressure control is performed. The shaft-like member 44 is a member that forms a part of the drive shaft 42 and constitutes the drive shaft 42 together with the mover 43 (described later).

  The piston member 30 is provided with projecting portions 31 and 24 projecting in a flange shape outward in the radial direction at the upper end and the lower end in the axis O direction. The overhang part 31 is a part disposed on the first liquid chamber 17a side, and the overhang part 24 is a part disposed on the second liquid chamber 17b side. The diameters of the overhang portions 31 and 24 are larger than the inner diameter of the insertion hole 20. Therefore, when the displacement of the piston member 30 in the direction approaching the actuator 40 reaches a predetermined amount or more, the overhanging portion 31 comes into contact with the upper surface of the partition plate 19, thereby restricting the displacement of the piston member 30. The Further, when the displacement of the piston member 30 in the direction approaching the vibration isolating base 15 reaches a predetermined amount or more, the overhanging portion 24 comes into contact with the lower surface of the partition plate 19 so that the displacement of the piston member 30 is reduced. Be regulated.

  The actuator 40 is a movable iron core electromagnet type linear actuator, and is housed and held in a housing space formed by the bottom metal fitting 14 in a state of being sealed from the outside. The actuator 40 includes a stator 41 fixed to the second fixture 12, and a mover 43 that is supported so as to reciprocate with respect to the stator 41 and is connected to the piston member 30. The mover 43 is a shaft-like member disposed in a vertical position along the axis O of the second fixture 12 (coaxially in the present embodiment), and its tip is attached to the piston member 30. The movable member 43 and the shaft-shaped member 44 are integrally connected to the shaft-shaped member 44 so that the piston member 30 is vibrated and displaced (reciprocated) vertically along the axis O direction.

  The drive shaft 42 (a part of the movable member) includes a movable element 43, a shaft-shaped member 44, and a bolt. The mover 43 is formed in a cylindrical shape having a through hole along the axis O, while the shaft-shaped member 44 is provided with a threaded portion that is open on the base end side and has a female screw formed on the inner peripheral surface thereof. The front end of the bolt inserted from the base end side of the mover 43 is screwed into the female thread portion of the shaft-like member 44, whereby the mover 43 and the shaft-like member 44 are integrally connected, and the drive shaft 42 is configured. Is done.

  The mover 43 has a magnetic material portion 45 (a part of the moveable member) as a mover core formed by laminating a large number of metal plates made of a magnetic metal such as an electromagnetic steel plate on the outer peripheral surface. A plurality (two in this embodiment) of magnetic material portions 45 are provided with a predetermined interval in the direction of the axis O. The mover 43 is capable of reciprocating in the direction of the axis O with respect to the stator 41 via a plate spring 46 that is a pair of upper and lower elastic support members, and the position of the axis O and the axis O are orthogonal to each other. It is supported in a state where the direction position is positioned.

  The stator 41 has an annular shape that surrounds the outer periphery of the mover 43 coaxially, and supports the mover 43 so that it can reciprocate in the direction of the axis O in its hollow portion. It is held in a lowered state. The mounting plate 25 is caulked and fixed by the bottom metal fitting 14 together with the cylindrical metal fitting 13 and the attachment plate 23 of the diaphragm 18.

  The stator 41 is arranged in a radial direction from both sides so that a yoke 47 formed by laminating a large number of annular metal plates made of a magnetic metal such as an electromagnetic steel plate and the central portion of the yoke 47 are opposed to each other with the magnetic material portion 45 interposed therebetween. A pair of magnetic pole portions 48 projecting inward are provided.

  The tip of the magnetic pole part 48 of the stator 41 facing the magnetic material part 45 (that is, the inner end of the magnetic pole part 48) is adjacent to the moving element 43 along the reciprocating direction (axis O direction). A pair of upper and lower permanent magnets 50 and 51 facing the mover 43 while being arranged in parallel are orthogonal to the reciprocating direction of the mover 43 so that their magnetic poles are NS different from each other. The magnetic poles are arranged in the direction, and the arrangement of the magnetic poles (N pole and S pole) is reversed. In the present embodiment, two pairs of upper and lower permanent magnets 50 and 51 are arranged in parallel in the axis O direction so as to correspond to the magnetic material portion 45.

  A coil 52 is wound around each of the pair of magnetic pole portions 48 of the stator 41 around the axis in the direction orthogonal to the reciprocating direction (axis O direction) of the mover 43 to form a pair of permanent magnets. The magnetic flux passing through 50 and 51 can be generated. In the present embodiment, a pair of permanent magnets 50 and 51 are provided at the inner end portions of the pair of magnetic pole portions 48 of the stator 41 facing each other with the magnetic material portion 45 interposed therebetween. Are opposed to each other with the mover 43 sandwiched in a direction orthogonal to the reciprocating direction of the mover 43, and the arrangement of the magnetic poles is reversed left and right (left and right in FIG. 1) so that the opposing magnetic poles are different from each other. It is arranged.

  When the coil 52 of the actuator 40 is in a demagnetized state, the drive shaft 42 supported by the leaf spring 46 so as to be displaceable in the direction of the axis O with respect to the stator 41 has the weight of the piston member 30 and the drive shaft 42 and the leaf spring. It stops at a position where the elastic force of 46 is balanced. When a positive excitation current is passed through the coil 52 from this state, the direction of the magnetomotive force generated in the coil 52 is the same as the direction of the magnetomotive force of the upper permanent magnet 50, and the magnetomotive force is increased. On the other hand, the direction of the magnetomotive force of the lower permanent magnet 51 and the direction of the magnetomotive force of the coil 52 are reversed, and the magnetomotive forces of the two are canceled out and weakened. As a result, an upward force acts on the magnetic material portion 45, and the mover 43 is raised while elastically deforming the leaf spring 46. Since the piston member 30 coupled to the mover 43 moves upward, the volume of the first liquid chamber 17a decreases.

  On the other hand, when an exciting current in the reverse direction is supplied to the coil 52, a downward force is applied to the magnetic material portion 45, and the mover 43 is lowered while elastically deforming the leaf spring 46. Since the piston member 30 coupled to the mover 43 moves downward, the volume of the first liquid chamber 17a increases. Thus, by alternately switching the direction of the excitation current of the coil 52 in the forward and reverse directions, the drive shaft 42 and the piston member 30 can be reciprocated up and down to change the volume of the first liquid chamber 17a.

  When the coil 52 of the actuator 40 is in a demagnetized state, if a load is input to the first fixture 11 and the vibration isolating base 15 is elastically deformed to increase the internal pressure of the first liquid chamber 17a, the piston member 30 and the drive shaft 42 is pushed (lowered) to the actuator 40 side. A spring constant that is a ratio of a thrust generated in the piston member 30 due to an increase in the internal pressure of the first liquid chamber 17a (a force pushed out of the first liquid chamber 17a) and a displacement of the piston member 30 generated by the thrust, and the piston member 30 The natural frequency of the piston member 30 and the drive shaft 42 is determined by the mass of the drive shaft 42 (see FIG. 2). This spring constant is mainly determined by the leaf spring 46, but can be adjusted by causing the piston member 30 to interfere with the partition plate 19 in the insertion hole 20. Since the mass of the screw 33 and the drive shaft 42 of the piston member 30 can be adjusted relatively easily (the mass can be changed), the natural frequency can be adjusted relatively easily.

  This natural frequency is set within a frequency band of vibration that drives the actuator 40 to exhibit the vibration isolation function. In the present embodiment, the natural frequency is set within a range of 30 Hz to 100 Hz, which is narrower than the frequency band of vibrations that drive the actuator 40 to exhibit the vibration isolation function.

  A method of manufacturing the active vibration isolator 10 (see FIG. 1) configured as described above will be described. The first molded body in which the first fixture 11 and the second fixture 12 (tubular fitting 13) are connected by the vibration isolating base 15, the diaphragm 18 and the overhanging portion 24 are integrally molded and the mounting plate 23 is formed. The second molded body to which the shaft-like member 44 is vulcanized and bonded, and the piston member 30 are each vulcanized and molded by a rubber vulcanization mold. After the vulcanization molding by the rubber vulcanization mold, first, the second molded body is assembled to the partition plate 19 to assemble the intermediate assembly. Specifically, the partition plate 19 and the second molded body are submerged in the liquid, the piston member 30 is inserted into the insertion hole 20 of the partition plate 19, and the piston member 30 is fixed to the shaft-shaped member 44 with the screw 33.

  Next, the first molded body is also submerged in the liquid, and the intermediate assembly is inserted from the lower opening of the first molded body into the cylindrical fitting 13 from the partition plate 19 side, and the first assembly is assembled in the liquid. Thereafter, the first assembly is taken out of the liquid with the first attachment 11 being in the downward position, and while maintaining this posture, the actuator 40 is stacked from the lower surface side of the diaphragm 18, and the shaft-shaped member 44 and the mover 43 are overlapped. Is fastened with bolts. And the bottom metal fitting 14 is put on the actuator 40, and the bottom metal fitting 14 is fixed to the lower opening of the cylindrical metal fitting 13 by caulking. Thereby, the manufacture of the active vibration isolator 10 is completed.

  Next, the electrical configuration of the active vibration isolator 10 will be described with reference to FIG. FIG. 3 is a block diagram showing an electrical configuration of the active vibration isolator 10. As shown in FIG. 3, the actuator 40 of the active vibration isolator 10 is controlled by an ECU 60 (Electronic Control Unit). The ECU 60 includes a CPU 61, a ROM 62, and a RAM 63, which are connected to the input / output port 65 via the bus line 64. A device such as a crank pulse sensor 71 is connected to the input / output port 65.

  The CPU 61 is an arithmetic unit that controls each unit connected by the bus line 64, and the ROM 62 stores a control program executed by the CPU 61 (for example, the program of the flowcharts shown in FIGS. 4 to 6), fixed value data, and the like. This is a non-rewritable non-volatile memory to be stored. The RAM 63 is a memory for storing various data in a rewritable manner when executing the control program.

  The crank pulse sensor 71 is a sensor that detects a crank pulse that is output as the crankshaft of the engine rotates, and includes an output circuit (not shown) that processes the detection result and outputs the result to the CPU 61. The TDC pulse sensor 72 is a sensor that detects a top dead center (TDC) pulse of each cylinder of the engine, and includes an output circuit (not shown) that processes the detection result and outputs the result to the CPU 61. .

  The drive circuit 73 is a switching circuit that supplies current to the coil 52 (see FIG. 1) of the actuator 40. The current sensor 74 is a sensor that detects a current that actually flows through the coil 52, and includes an output circuit (not shown) that processes the detection result and outputs the result to the CPU 61. The current amplifier 75 is a device that amplifies a direct current that flows through the coil 52.

  The acceleration sensor device 76 is a sensor that detects the longitudinal acceleration (front-rear G) and the lateral acceleration (lateral G) of the automobile, and has an output circuit (not shown) that processes the detection result and outputs it to the CPU 61. I have. The CPU 61 integrates the detection results (front and rear G, lateral G) input from the acceleration sensor device 76 with respect to time to calculate speeds in two directions (front and rear directions and left and right directions), and synthesizes these two direction components. Thus, the traveling speed of the car is acquired.

  The other input / output device 77 is a sensor attached to the crankshaft of the engine, which detects the engine speed and outputs the detection result to the CPU 61, and the operation amount of an accelerator pedal (not shown). Examples include an accelerator pedal sensor that detects and outputs a detection result to the CPU 61, a shift position sensor that detects a shift position of the transmission and outputs the detection result to the CPU 61, and the like. The CPU 61 can determine the driving state of the automobile from the detection results of these sensors.

  Next, ACM processing will be described with reference to FIGS. 4 is a flowchart of ACM processing, FIG. 5 is a flowchart of constraint processing, and FIG. 6 is a flowchart of movable processing. The ACM process is a process that is repeatedly executed by the CPU 61 (for example, at intervals of 0.2 seconds) while the power of the ECU 60 is turned on, and controls the actuator 40 to provide the vibration isolating function to the active vibration isolator 10. It is a process that demonstrates.

  As shown in FIG. 4, regarding the ACM processing, the CPU 61 acquires the acceleration (front-rear G) and the traveling speed of the vehicle (S1, S2), and determines whether the traveling speed of the vehicle is equal to or higher than a predetermined traveling speed. (S3). In the process of S3, the travel speed acquired in the process of S2 and the threshold value stored in advance in the ROM 62 corresponding to the travel speed (in this embodiment, travel that is determined to be traveling (not stopped)). Speed).

  As a result of the process of S3, when it is determined that the traveling speed of the automobile is equal to or higher than the predetermined traveling speed (S3: Yes), the CPU 61 determines whether the acceleration of the automobile is equal to or lower than the predetermined acceleration. (S4). In the process of S4, the acceleration acquired in the process of S1 is compared with a threshold value stored in advance in the ROM 62 corresponding to the acceleration (acceleration determined to be constant speed running in the present embodiment). . As a result of the process of S4, when it is determined that the acceleration of the vehicle is equal to or less than the predetermined acceleration (S4: Yes), it is determined that the vehicle is traveling at a constant speed with a small acceleration (S4: Yes). ), The CPU 61 executes a restraining process (S5) on the actuator 40.

  On the other hand, if it is determined as a result of the processing in S3 that the vehicle traveling speed is less than the predetermined traveling speed (S3: No), the vehicle is stopped (engine stopped) or is idling. It is judged that As a result of the process of S4, when it is determined that the acceleration of the vehicle exceeds a predetermined acceleration (S4: No), it is determined that the vehicle is being accelerated or decelerated. In these cases, the CPU 61 performs a movable process (S6) on the actuator 40.

  The restraint process (S5) shown in FIG. 5 is executed when the automobile is traveling at a constant speed with a small acceleration. When engine shake vibration of a low frequency (for example, 7 Hz to 20 Hz) is generated as the automobile runs at a constant speed, the vibration-proof base 15 is elasticized by a load input from the engine via the first fixture 11 (see FIG. 1). Deformation changes the volume of the first liquid chamber 17a. Then, the liquid goes back and forth between the first liquid chamber 17a and the second liquid chamber 17b connected via the orifice 21. When the volume of the first liquid chamber 17a is enlarged / reduced, the volume of the second liquid chamber 17b is reduced / expanded accordingly. The change in volume of the second liquid chamber 17b is absorbed by the elastic deformation of the diaphragm 18. . Since the shape and size of the orifice 21 and the spring constant of the vibration-proof base 15 are set so as to exhibit low spring characteristics and high damping force in the frequency region of engine shake vibration, vibration transmitted from the engine to the vehicle body can be reduced. Can be reduced.

  However, when the piston member 30 is displaced by the thrust accompanying the change in the internal pressure of the first liquid chamber 17a due to the volume change of the first liquid chamber 17a, the volume change of the first liquid chamber 17a is absorbed by the displacement of the piston member 30. As a result, the amount of liquid flowing back and forth between the first liquid chamber 17a and the second liquid chamber 17b through the orifice 21 is reduced, so that a desired damping force may not be obtained. In order to prevent this, the CPU 61 executes a restraining process (S5). The restraining process (S5) is a process for restricting the displacement of the piston member 30 while the vehicle is traveling at a constant speed to ensure the vibration isolating performance in the frequency region of engine shake vibration.

  As shown in FIG. 5, the CPU 61 determines whether or not a current flows through the coil 52 (see FIG. 1) in relation to the restraining process (S5) (S11, current detection means). The current flowing through the coil 52 is an induced current generated in the coil 52 when the piston member 30 and the drive shaft 42 are displaced with respect to the coil 52, and is detected by a current sensor 74 (see FIG. 3). When the CPU 61 determines that no current flows through the coil 52 as a result of the process of S11 (S11: No), the restriction process (S5) is terminated.

  On the other hand, if the CPU 61 determines that a current flows through the coil 52 as a result of the process of S11 (S11: Yes), the current amplifier is configured so that the reaction force (electromagnetic force against thrust) by the coil 52 increases. A direct current is passed through the coil 52 through 75 (S12, limiting means). As a result, the coil 52 is excited and the displacement of the piston member 30 and the drive shaft 42 is restricted. As a result, it is possible to secure the amount of liquid that passes between the first liquid chamber 17a and the second liquid chamber 17b through the orifice 21 as the volume of the first liquid chamber 17a changes. Therefore, low spring characteristics and high damping force can be secured in the frequency region of engine shake vibration.

  Further, the CPU 61 detects an induced current generated in the coil 52 when the piston member 30 and the drive shaft 42 are displaced with respect to the coil 52, and restricts the displacement of the piston member 30 and the drive shaft 42 based on the detection of the current. To do. Since the movement of the piston member 30 and the drive shaft 42 can be limited in a short time after the piston member 30 and the drive shaft 42 move due to the thrust accompanying the increase in the internal pressure of the first liquid chamber 17a, the response delay (piston member 30 The displacement of the piston member 30 caused by the time difference from the start of movement to the stop of movement) can be minimized. Therefore, it is possible to suppress the deterioration of the vibration isolation performance caused by the response delay.

  It should be noted that vibration at a higher frequency than engine shake vibration (for example, vibration during idling (for example, 20 Hz to 40 Hz) due to rotation of the crankshaft of the engine, vibration during acceleration operation (for example, 100 Hz to 200 Hz), vibration during cylinder deactivation ) Occurs, the orifice 21 connecting the first liquid chamber 17a and the second liquid chamber 17b is clogged. Then, since the anti-vibration performance due to the liquid flowing through the orifice 21 is not exhibited, the CPU 61 drives the actuator 40 by the movable process (see S6, FIG. 6) to exhibit the anti-vibration performance.

  The movable process (S6) shown in FIG. 6 is executed when the vehicle is stopped (in an engine stop state or an idle operation state) or during acceleration / deceleration operation of the automobile. In relation to the movable process (S6), the CPU 61 acquires a crank pulse detected by the crank pulse sensor 71 (a pulse output at every predetermined crank angle), and acquires a TDC pulse detected by the TDC pulse sensor 72 (S21). ). Next, the CPU 61 calculates the time interval of the crank pulse by comparing the acquired crank pulse with a reference crank pulse (TDC pulse of a specific cylinder) (S22). Next, the CPU 61 calculates the crank angular velocity ω by dividing the crank angle by the time interval of the crank pulse (S23), and calculates the crank angular acceleration dω / dt by differentiating the crank angular velocity ω with respect to time (S24).

  Next, the CPU 61 calculates the torque Tq around the crankshaft of the engine by Tq = I × dω / dt (S25). Where I is the moment of inertia around the crankshaft of the engine. The torque Tq is zero assuming that the crankshaft is rotating at a constant angular velocity ω. However, in the expansion stroke, the angular velocity ω increases due to the acceleration of the piston, and in the compression stroke, the angular velocity ω decreases due to the deceleration of the piston. Since the angular acceleration dω / dt is generated, a torque Tq proportional to the crank angular acceleration dω / dt is generated.

  Next, the CPU 61 determines the maximum value (maximum torque) and the minimum value (minimum torque) of the temporally adjacent torque (S25), and determines the difference between the maximum value and the minimum value of the torque, that is, the amount of torque fluctuation. The amplitude (the magnitude of engine vibration) at the position of the active vibration isolator 10 to be supported is calculated (S27). The CPU 61 determines the output timing and duty waveform of the current to be passed through the coil 52 of the actuator 40 based on the calculated magnitude of the engine vibration and the phase of the engine vibration, and the drive circuit 73 supplies an alternating current (sine wave signal) to the coil 52. Or a rectangular wave signal) (S28). Note that when the engine is stopped, no crank pulse is generated, so no current flows through the coil 52.

  When the engine is displaced downward due to vibration and the volume of the first liquid chamber 17a is reduced, an exciting current is caused to flow through the coil 52 in synchronization with the processing in S28, and a downward force is applied to the magnetic material portion 45. The mover 43 is lowered while the leaf spring 46 is elastically deformed. Since the piston member 30 coupled to the mover 43 moves downward, the volume of the first liquid chamber 17a increases. As a result, an increase in the fluid pressure in the first fluid chamber 17a can be suppressed, so that the active vibration isolator 10 can actively suppress the transmission force from the engine to the vehicle body.

  On the contrary, when the engine is displaced upward due to vibration and the volume of the first liquid chamber 17a is increased, the exciting current is supplied to the coil 52 in synchronization with the processing in S28, and the magnetic material portion 45 is directed upward. When this force is applied, the mover 43 rises while the leaf spring 46 is elastically deformed. Since the piston member 30 coupled to the mover 43 moves upward, the volume of the first liquid chamber 17a decreases. As a result, a decrease in the fluid pressure in the first fluid chamber 17a can be suppressed, so that the active vibration isolator 10 can actively suppress the transmission force from the engine to the vehicle body.

  In the present embodiment, a spring constant that is a ratio between a thrust (force in the direction of the axis O) generated in the piston member 30 due to a change in the internal pressure of the first liquid chamber 17a and a displacement amount of the piston member 30 generated by the thrust, The natural frequency of the piston member 30 and the drive shaft 42 determined by the mass of the piston member 30 and the drive shaft 42 is within the frequency band (20 Hz to 200 Hz) of the vibration that drives the actuator 40 and exhibits the anti-vibration function. Is set. As a result, since the actuator 40 can apply vibration substantially equal to the natural frequency to the drive shaft 42, strong vibration can be generated by resonance even if the output of the actuator 40 is small. Since the actuator 40 with a small output can be employed, the actuator 40 can be reduced in size (especially with a low profile). Further, since the piston member 30 and the drive shaft 42 can be easily vibrated, the current flowing through the coil 52 can be reduced. Therefore, the power consumption of the actuator 40 can be reduced.

  In addition, the natural frequency of the piston member 30 and the drive shaft 42 includes a first frequency (30 Hz) representing vibrations to be suppressed (for example, 20 Hz to 40 Hz) in the idling operation state of the automobile and vibrations to be suppressed in the driving operation state of the automobile. It is a frequency that represents (for example, 100 Hz to 200 Hz) and is set to a second frequency (100 Hz) that is higher than the first frequency. Therefore, in any of the idling operation state and the traveling operation state, the vibration frequency of the piston member 30 driven (vibrated) by the actuator 40 and the natural frequency of the piston member 30 and the drive shaft 42 can be brought close to each other. . Therefore, the power consumption of the actuator 40 can be reduced in both the idle operation state and the traveling operation state.

  The actuator 40 drives the piston member 30 in a frequency range lower than the natural frequency (for example, 20 Hz to 40 Hz) in the idling operation state of the automobile, and the frequency range higher than the natural frequency (for example, 100 Hz to higher in the driving operation state of the automobile). The piston member 30 is driven at 200 Hz). Therefore, it is possible to ensure the vibration-proof performance in the idle operation state and the traveling operation state while preventing the piston member 30 from becoming difficult to control due to resonance.

  Here, the actuator 40 generates a reaction force against the thrust generated in the piston member 30 by the internal pressure of the first liquid chamber 17a changed by the deformation of the vibration isolation base 15 by the restraining process (S5, reaction force generation means). . Thereby, the movement of the piston member 30 when the internal pressure of the 1st liquid chamber 17a changes can be suppressed. As a result, since the volume change of the first liquid chamber 17a due to the change of the piston member 30 can be suppressed, a spring constant of the vibration isolating base 15 and a damping force set in advance by the orifice 21 can be obtained, and active vibration isolation The anti-vibration performance of the device 10 can be ensured.

  In addition, by the ACM process (see FIG. 4), information regarding the driving state of the vehicle is acquired by the processing of S1 and S2 (information acquisition means), and whether the acquired driving state of the vehicle is a predetermined driving state or not. , S4 (operation state determination means). As a result of the determination, when the driving state of the automobile is a constant speed running state (S4: Yes), the process of S5 (reaction force generating means) is executed. Therefore, it is possible to secure a vibration isolation performance that suppresses engine shake vibration when the automobile is in a constant speed traveling state.

  Further, when it is determined whether the driving state of the vehicle is a predetermined driving state or not by the processing of S3 and S4 (driving state determination means), the driving state of the vehicle is an idle driving state or an acceleration / deceleration driving state ( (S3: No, S4: No), the process of S6 (movable process) is executed. In the movable process (S6), it is possible to actively suppress the transmission force that transmits the vibration of the engine to the vehicle body during idle operation or acceleration / deceleration operation. Therefore, it is possible to ensure the vibration isolation performance in the constant speed running state, the idle operation state, and the acceleration / deceleration operation state of the automobile.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  In the above-described embodiment, the liquid chamber 17 is partitioned by the partition plate 19 to form the first liquid chamber 17a and the second liquid chamber 17b, and the orifice 21 is provided between the first liquid chamber 17a and the second liquid chamber 17b. Although the case of being connected has been described, the present invention is not necessarily limited to this. For example, it is naturally possible to connect the first liquid chamber 17a and the second liquid chamber 17b with a plurality of orifices according to the required vibration-proof performance. In addition to the first liquid chamber 17a and the second liquid chamber 17b, it is naturally possible to have one or more sub liquid chambers. In this case, the two liquid chambers among the first liquid chamber 17 a, the second liquid chamber 17 b, and the sub liquid chamber can be communicated with each other by one or more orifices other than the orifice 21. Further, it is naturally possible to provide an elastic film in the liquid chamber 17 that suppresses vibrations having a frequency higher than the vibration frequency suppressed by the orifice 21.

  Although the case where the active vibration isolator 10 is used as an engine mount that elastically supports an automobile engine has been described in the above embodiment, the present invention is not necessarily limited thereto. It is naturally possible to apply the active vibration isolator 10 to a vibration isolator that suppresses vibration of an arbitrary vibrating body such as a body mount or a differential mount.

  In the above embodiment, the active vibration isolator 10 is described in which the diaphragm 18 is disposed below the vibration isolation base 15 so that the second liquid chamber 17b is provided below the first liquid chamber 17a. However, the present invention is not limited to this, and the anti-vibration base 15 and the diaphragm 18 can be arranged at arbitrary positions. For example, it is naturally possible to dispose a diaphragm above the vibration isolation base and provide the second liquid chamber above the first liquid chamber. In this case, an orifice for connecting the first liquid chamber and the second liquid chamber is formed on the outer periphery of the vibration-proof base.

  In the above embodiment, the case where the actuator 40 is energized with an alternating current (sine wave signal, rectangular wave signal, etc.) to excite the coil 52 and the drive shaft 42 elastically supported by the leaf spring 46 is reciprocated has been described. However, it is not necessarily limited to this. In the case of an actuator in which the drive shaft is urged to one side in the direction of the axis O by the coil spring, the coil is excited when the coil is intermittently energized and deenergized by intermittently supplying a direct current to the coil. Thus, the coil spring can be compressed to displace the drive shaft, and the drive shaft can be displaced by the restoring force of the coil spring by demagnetizing the coil. Even in an active vibration isolator employing such an actuator, the same actions and effects as in the present embodiment can be realized.

  In the above embodiment, the active vibration isolator 10 that changes the volume of the first liquid chamber 17a by the piston member 30 that reciprocates in the insertion hole 20 of the partition plate 19 has been described, but the present invention is not necessarily limited thereto. Absent. In this embodiment, an active vibration isolator that changes the volume of the liquid chamber by displacing the rubber film (movable member) constituting a part of the wall surface of the liquid chamber with an actuator instead of the piston member 30 has been described in the present embodiment. It is of course possible to apply the technology.

  In the above embodiment, in the ACM process (see FIG. 4), the output timing and duty waveform of the current flowing through the coil 52 of the actuator 40 are determined based on the magnitude (amplitude) and phase of the engine vibration calculated by the CPU 61. Although the case has been described, the present invention is not necessarily limited to this. For example, the CPU 61 (see FIG. 3) can acquire the operating state correlated with the frequency, amplitude, and phase from the detection result of the rotation speed sensor (other input / output device 77) that detects the rotation speed of the engine. . If the output signal of the current flowing through the coil 52 of the actuator 40 is stored in the ROM 62 as a data map for each frequency in the operating state, the CPU 61 can read out a suitable data map from the ROM 62. The CPU 61 generates a control signal based on the read data map and outputs it to the drive circuit 73. When the drive circuit 73 generates a drive signal based on the input control signal, the actuator 40 is energized and the excitation force of the active vibration isolator 10 is exerted on the engine side. Thereby, the vibration proof performance is easily demonstrated compared with this Embodiment. This is an example, and other known control means (processing method) can be employed.

10 Active vibration isolator 15 Vibration isolator base (elastic body)
17a First liquid chamber (liquid chamber)
30 Piston member (part of movable member)
40 Actuator 42 Drive shaft (part of movable member)

Claims (2)

An elastic body that receives vibration of a vibration body mounted on the vehicle;
A liquid chamber in which the elastic body forms at least a part of the wall surface;
A movable member that changes the volume of the liquid chamber;
An actuator that drives the movable member with electromagnetic force;
The actuator includes a reaction force generating means for generating a reaction force against a thrust generated in the movable member by an internal pressure of the liquid chamber changed by deformation of the elastic body ,
A coil to which an excitation current for driving the movable member is input,
The reaction force generation means includes a current detection means for detecting a current flowing in the coil by the thrust,
An active vibration isolator comprising: a restricting means for restricting the movement of the movable member by causing a current to flow through the coil when a current is detected by the current detecting means . Information acquisition means for acquiring information relating to the driving state of the vehicle;
Driving state determination means for determining whether the driving state of the vehicle acquired by the information acquisition unit is a predetermined traveling driving state;
The reaction force generation means, according to claim 1 Symbol placement of the active vibration isolation device characterized in that it is executed when the operating condition of the vehicle by said driving state determining means is determined to be a constant speed running state .

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