JP5108458B2 - Electric actuator and fluid-filled vibration isolator using the same - Google Patents

Description

  The present invention relates to an electric actuator that reciprocates an output member using the rotational driving force of the electric motor by energizing the electric motor, and a fluid-filled vibration isolator capable of switching the vibration isolating characteristics by the electric actuator. About.

  Conventionally, an electric actuator in which an output member is linearly reciprocated by energization is known. For example, the member is interposed between members constituting a vibration transmission system, and these members are connected to each other for vibration prevention or vibration prevention support. In the fluid-filled vibration isolator to be used, it is employed as an actuator for switching the vibration isolating characteristics. Patent Document 1 (Japanese Patent Laid-Open No. 2000-161457) shows an example of an electric actuator in which such an output member is reciprocated.

  In such an electric actuator in which the output member is reciprocally operated, it may be necessary to control the position of the output member with high accuracy. For example, in a fluid-filled vibration isolator that is structured to switch between the fluid flow communication state and the block state using the reciprocating operation of the output member of the electric actuator, switching of the vibration isolation characteristics is effectively realized. Therefore, it is desirable that the position control of the output member is performed with high accuracy in the electric actuator.

  Therefore, conventionally, as a means for controlling the position of the output member, for example, the position of the output member is directly detected using a position sensor such as a photoelectric tube or a limit switch, and the operation of the electric actuator is performed based on the detection result. The method etc. which control are adopted.

  However, in the position control means using such a position sensor, an increase in the number of parts and a complicated structure cannot be avoided, and an increase in the size of the apparatus tends to be a problem. In addition, the use of an expensive position sensor may increase the cost.

  On the other hand, the time until the output member reaches the displacement end in the reciprocating direction is measured or predicted in advance, and the position of the output member is controlled by controlling energization according to the time. .

  However, especially when an electric motor is used as the driving force source of the output member under conditions in which an error occurs in the supply voltage, etc., the output member per unit time depends on the power supplied to the electric motor. Due to the difference in displacement, it has been extremely difficult to accurately and stably control the position of the output member in the reciprocating operation direction.

JP 2000-161457 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that the position of the output member in the reciprocating operation direction can be accurately controlled with a simple structure. An object of the present invention is to provide an electric actuator having a novel structure, and a fluid-filled vibration isolator having a novel structure capable of switching and controlling vibration isolation characteristics with high accuracy by using the electric actuator.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

That is, the present invention relates to an electric actuator having an output member that is linearly reciprocated by converting a rotational driving force of an electric motor driven by DC power into a linear driving force via a power conversion mechanism. Switching means for switching the polarity of the DC power supplied to the electric motor is provided, the rotation direction of the electric motor is changed by the switching operation of the switching means, and the driving direction of the output member is restored to the forward direction. On the first power supply path that supplies the electric motor with the DC power of the polarity that drives the output member in the forward direction, the contact state is brought about by the displacement of the output member. A first switch means having a first electrode and a first brush which are displaced relative to each other, the first brush being detached from the first electrode and in contact When the first power supply path is released and the displacement end of the output member in the forward direction is defined, the DC power having the polarity for driving the output member in the backward direction is generated. On the second power supply path for supplying power to the electric motor, there is provided a second switch means having a second electrode and a second brush which are relatively displaced in contact with the displacement of the output member. The second brush is detached from the second electrode, the contact state is released, and the second power feeding path is cut off, so that the return end of the output member in the backward direction is defined. Further, the second switch means is maintained in the connected state at the cutoff position of the first switch means, and the first switch means is connected at the cutoff position of the second switch means. Is supposed to be maintained Meanwhile, at least one of the screw structure and the worm gear structure from the electric motor on the transmission path of driving force to the output member is provided, transmit the rotational driving force of the electric motor as a reciprocating drive force to the output member The power conversion mechanism is configured to include at least one of the screw structure and the worm gear structure, the first power supply path is blocked, and the displacement end of the output member in the forward direction is defined. The output member is held at the displacement end by the meshing action of the threads in the power conversion mechanism in a state where the second power supply path is blocked and the displacement end in the backward direction of the output member is defined. It is characterized by being designed .

  In such an electric actuator having a structure according to the present invention, by switching between a contact state and a non-contact state between the electrode and the brush provided on the power supply path, DC power of one polarity is supplied to the electric motor. The displacement end of the output member is defined by selectively blocking the first and second power supply paths. As a result, the stroke of the reciprocating operation of the output member can be stably defined with a simple structure.

Further, when the output member is positioned at the displacement end, one switch means is cut off and the other switch means is maintained in the connected state. According to this, the output member is stopped at the displacement end by blocking one of the switch means, and the other switch means is maintained in the connected state, so that the output member is removed from the one displacement end. It becomes possible to quickly supply the electric power to the electric motor with the DC power having the polarity driven toward the other displacement end side. Therefore, in the reciprocating operation of the output member, the amount of displacement can be set with high accuracy, and the operating member can be quickly shifted from the stopped state to the driven state. Furthermore, in the electric actuator according to the present invention, the rotational driving force of the electric motor is converted into a linear driving force by providing a screw structure or a worm gear structure on the driving force transmission path from the electric motor to the movable valve element. Can be transmitted to the output member and the holding force can be applied to the output member when the electric motor is de-energized by the meshing action of the screw threads exhibited in the screw structure and the worm gear structure. The member can be stably held in the switching displacement state. As described above, since the holding force of the output member can be effectively obtained without energizing the electric motor, continuous power supply to the electric motor becomes unnecessary when the switching state of the output member is maintained. Problems such as heat generation due to continuous energization of the electric motor and an increase in the amount of electric power consumed can be avoided.

  Further, in the electric actuator according to the present invention, the DC power of the polarity that drives the output member in the forward direction is allowed to be fed to the electric motor, and the DC power of the polarity that drives the output member in the backward direction is allowed. First rectifying means for blocking power supply to the electric motor is provided on the first power supply path, and DC power having a polarity for driving the output member in the backward direction is supplied to the electric motor. A second rectifying means is provided on the second power supply path to permit and block power supply to the electric motor of the DC power having the polarity for driving the output member in the forward direction. It is preferable that the switching means includes a means and a second rectifying means.

  Using such rectifying action by the first and second rectifying means, a first power supply path for supplying the electric motor with DC power having a polarity for driving the output member in the forward direction, and the output member in the backward direction. The second power supply path for supplying DC electric power having the driving polarity to the electric motor can be realized with a simple structure.

In the electric actuator according to the present invention, preferably, the power conversion mechanism includes a power transmission member, and the first electrode, the second electrode, the first brush, and the first One of the two brushes is provided on the power transmission member, and the first electrode and the second electrode are disposed so as to extend in the operation direction of the power transmission member with respect to the reciprocating operation of the output member. In addition, the end of the first electrode and the end of the second electrode are displaced from each other in the operating direction of the power transmission member, while the first direction in the operating direction of the power transmission member The brush and the second brush are provided at the same position.

  As described above, any one of the first electrode, the second electrode, the first brush, and the second brush is attached to the power transmission member, and the first electrode and the second electrode extend from each other. And the first brush and the second brush are arranged at positions aligned with each other in the extending direction of the electrode, so that the switch means composed of the electrode and the brush The connected state and the disconnected state are switched according to the operation of the power transmission member, and the output member is stably reciprocated with a predetermined stroke.

  Further, in the electric actuator according to the present invention, any one of the first electrode, the second electrode, the first brush, and the second brush is provided on the output member, The first electrode and the second electrode are provided so as to extend linearly in the reciprocating operation direction of the output member, and the end portions of the first electrode and the second electrode are reciprocated of the output member. They may be offset from each other in the direction of operation.

  According to this, by providing either the electrode or the brush with respect to the output member, switching of the switch means according to the displacement of the output member can be realized with high accuracy. In particular, the first and second electrodes are disposed so as to extend linearly in the reciprocating direction of the output member, and the ends of the first electrode and the second electrode are mutually connected in the extending direction of the electrodes. By disposing them, the connection state of one of the first switch means and the second switch means and the cutoff state of the other can be effectively realized in a state where the output member is positioned at the displacement end. I can do it.

On the other hand, according to the present invention, the first mounting member and the second mounting member are connected by the main rubber elastic body, and a part of the wall portion is configured by the main rubber elastic body to enclose the incompressible fluid. Forming a pressure-receiving chamber and an equilibrium chamber in which a part of the wall is formed of a flexible membrane and enclosing an incompressible fluid, and the fluid is sealed by communicating the pressure-receiving chamber and the equilibrium chamber with each other by a fluid channel In the vibration isolator, the communication state and the cutoff state of the fluid flow path are switched by the reciprocating drive of the output member constituting the electric actuator according to any one of claims 1 to 4 . It is also characterized.

  As described above, by using the output member of the electric actuator according to the present invention as the valve means for switching the communication state and the blocking state of the fluid flow path, the fluid flow path switching control can be realized with high accuracy. Thus, it is possible to stably achieve the desired switching of the anti-vibration performance.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIGS. 1 and 2 show an electric actuator 10 as an embodiment of the present invention. More specifically, the electric actuator 10 has an electric motor 12. In the following description, the vertical direction means the vertical direction in FIG. 1, which is the reciprocal operation direction of the movable member 28 described later, unless otherwise specified.

  The electric motor 12 is an existing electric motor, and has a rotating shaft 14 as a drive shaft. When DC power is supplied from the power supply device 16, a rotational force is applied to the rotating shaft 14, and the rotating shaft 14 is driven to rotate around the central axis. In particular, in the present embodiment, the rotation direction of the rotary shaft 14 can be changed according to the energization direction to the electric motor 12. In addition, as the electric motor 12, various well-known motors (electric motors), such as a separately excited DC motor, can be adopted. The power supply device 16 employs a combination of various DC power supplies, an AC power supply, and a rectifier that converts AC power into DC power. For example, an in-vehicle storage battery (battery) is preferably used. The

  A male screw member 18 as a screw portion is attached to the rotating shaft 14 of the electric motor 12. The male screw member 18 is a substantially cylindrical member having a thread formed on the outer peripheral surface thereof, and the rotation shaft 14 is inserted and fixed so as to extend on the central axis. The male screw member 18 is rotated as the rotary shaft 14 is driven to rotate.

  The electric motor 12 is attached to the support member 20. The support member 20 has a thick annular shape, and is formed of a hard synthetic resin in the present embodiment.

  Further, a holding cylinder portion 24 is formed on the inner peripheral edge portion of the support member 20. The holding cylinder portion 24 has a substantially cylindrical shape and extends upward from the inner peripheral edge portion of the support member 20. In addition, the holding cylinder portion 24 is formed with a pair of engaging cutout portions 26 and 26 that open to the inner peripheral surface and the upper end surface at a portion opposed in one radial direction. The engagement notch 26 is formed in a groove shape having a substantially constant circumferential width dimension and extending in a predetermined length in the axial direction. In the present embodiment, both side surfaces in the circumferential direction spread in parallel with each other.

  The electric motor 12 is fitted and fixed in the central hole of the support member 20 so that the rotating shaft 14 of the electric motor 12 extends on the center line of the central hole of the support member 20. Thereby, the rotating shaft 14 is positioned so as to be separated from the inner peripheral side of the holding cylinder portion 24.

Further, a movable member 28 as an output member and a power transmission member is put on the tip portion of the rotating shaft 14. The movable member 28 has a substantially bottomed cylindrical shape in the reverse direction. In this embodiment, the movable member 28 is formed of a metal such as iron or an aluminum alloy, thereby improving the durability against deformation and wear. Further, a pressing flange portion 30 that extends toward the outer peripheral side is integrally formed at the upper end portion of the movable member 28. The pressing flange portion 30 in the present embodiment is chamfered so that the outer peripheral edge portion has a substantially hemispherical shape in the longitudinal section.

  Furthermore, a pair of engaging protrusions 32 and 32 are formed at the lower end portion of the movable member 28 so as to protrude toward the outer peripheral side from a portion facing in one radial direction. The engaging protrusion 32 is a substantially block-shaped protrusion, and both end faces in the circumferential direction are parallel to each other. Further, the width dimension in the circumferential direction of the engagement protrusion 32 is substantially equal to the width dimension in the circumferential direction of the engagement notch portion 26 formed in the holding cylinder portion 24, and the axial direction of the engagement protrusion 32. The dimension is sufficiently smaller than the axial dimension of the engagement notch 26.

  Further, the movable member 28 is provided with a female screw portion 34 as a screw contact portion. The female thread portion 34 is formed by utilizing the peripheral wall portion of the movable member 28 having a substantially bottomed cylindrical shape in the reverse direction, and a thread is engraved on the inner peripheral surface thereof over its entire length. Further, the screw thread constituting the female screw part 34 has a structure corresponding to the screw thread formed on the outer peripheral surface of the male screw member 18 attached to the rotating shaft 14.

  The movable member 28 having such a female screw portion 34 is attached to the rotating shaft 14 of the electric motor 12. That is, the movable member 28 is placed on the rotating shaft 14 from above, and the peripheral wall portion of the movable member 28 is positioned so as to surround the rotating shaft 14 while being spaced apart from the outer peripheral side of the rotating shaft 14. In the present embodiment, the rotating shaft 14 of the electric motor 12 is provided so as to extend in the reciprocating operation direction of the movable member 28 described later.

  Further, the male screw member 18 attached to the rotating shaft 14 is inserted into the inner peripheral side of the peripheral wall portion of the movable member 28, and the screw thread formed on the outer peripheral surface of the male screw member 18 and the inner peripheral surface of the movable member 28 are inserted. The thread of the formed female thread portion 34 is hooked. In other words, the male screw member 18 attached to the rotary shaft 14 is screwed into the female screw portion 34 of the movable member 28 from the lower opening. As a result, the movable member 28 is assembled to the rotating shaft 14, and a screw structure including the male screw member 18 and the female screw portion 34 is provided at a connecting portion between the rotating shaft 14 and the movable member 28.

  Further, since the rotating shaft 14 of the electric motor 12 is positioned on the inner peripheral side of the holding cylinder part 24, the movable member 28 is inserted into the holding cylinder part 24. 3, the engagement protrusion 32 formed integrally with the lower end portion of the movable member 28 is positioned in the circumferential direction with respect to the engagement notch portion 26 formed on the holding cylinder portion 24. The engagement protrusions 32 are fitted in the engagement notches 26. The movable member 28 is locked in the circumferential direction with respect to the holding cylinder portion 24 by the engagement action in the circumferential direction of the engagement protrusion 32 and the engagement notch portion 26 and is relatively non-rotatable. Such a locking of the movable member 28 and the holding cylinder portion 24 constitutes a rotation limiting mechanism for the movable member 28 in this embodiment.

  In this case, the rotational driving force generated by the electric motor 12 by power feeding is converted into a reciprocating driving force by a screw structure constituted by the male screw member 18 and the female screw part 34 and is applied to the movable member 28. . The movable member 28 can be driven and displaced to a predetermined position in the axial direction by controlling the rotation direction of the rotary shaft 14 in the electric motor 12. Hereinafter, the reciprocating operation in the axial direction of the movable member 28 will be described.

  First, the male screw member 18 attached to the rotating shaft 14 of the electric motor 12 is positioned at the lower end portion of the female screw portion 34 formed on the movable member 28, that is, the lower end opening in the peripheral wall portion of the movable member 28. In this case, the movable member 28 is positioned at the upper end in the reciprocating operation direction. Even in the state where the movable member 28 is positioned at the upper end in the driving direction as described above, the engagement protrusion 32 is positioned in the engagement notch 26 so that the engagement action by them is exhibited. It has become.

  Next, when the electric motor 12 is energized from the power supply device 16, the rotating shaft 14 is rotated to one side in the circumferential direction, and the male screw member 18 is rotated relative to the female screw portion 34, the male screw member. 18 is screwed into the female screw portion 34. As a result, the movable member 28 in which the female screw portion 34 is formed is relatively displaced downward in the axial direction with respect to the rotating shaft 14 to which the male screw member 18 is attached and the electric motor 12, and the lower end in the reciprocating operation direction. Can be moved to.

  In particular, in the present embodiment, the rotation of the movable member 28 is prevented by the engagement of the engagement protrusion 32 and the engagement notch 26, so that the rotational driving force of the rotating shaft 14 is between the male screw member 18 and the female screw portion 34. Therefore, the movable member 28 is prevented from rotating by being transmitted by friction or the like, and the drive displacement in the axial direction of the movable member 28 can be efficiently realized.

  Next, when the electric motor 12 is energized from the power supply device 16 and the rotating shaft 14 is rotated in the reverse direction in the circumferential direction, the male screw member 18 is rotated relative to the female screw portion 34, and the male screw The member 18 is twisted in the pulling direction with respect to the female screw portion 34. As a result, the movable member 28 in which the female screw portion 34 is formed is relatively displaced in the axial direction relative to the rotary shaft 14 and the electric motor 12 to which the male screw member 18 is attached, and the upper end in the reciprocating operation direction. Can be moved to. In the present embodiment, the rotating shaft 14 is reversely rotated by supplying a current having a reverse polarity to the electric motor 12.

  As described above, the rotational driving force generated by the electric motor 12 is converted into a linear driving force in the axial direction by the screw structure provided at the connecting portion of the rotating shaft 14 and the movable member 28, and is applied to the movable member 28. It is to be transmitted. The movable member 28 can be reciprocated up and down in the axial direction by switching the energization direction to the electric motor 12 and changing the rotation direction of the rotary shaft 14. As is clear from the above, in this embodiment, a power conversion mechanism that converts the rotational driving force of the electric motor 12 into a linear reciprocating driving force by a screw structure provided between the rotating shaft 14 and the movable member 28 is provided. It is configured.

  Here, the electric actuator 10 according to the present embodiment is provided with a control circuit 36 for controlling the reciprocating operation of the movable member 28. The control circuit 36 is provided on a power supply path from the power supply device 16 to the electric motor 12 and further includes a power supply device 38.

  The power feeding device 38 is a device that switches the polarity of the DC power fed from the power supply device 16 to the electric motor 12. In this embodiment, the direction of energization of the electric motor 12 based on the detection result of the connected sensor 40. Is to control. The sensor 40 in the present embodiment detects the running state of the automobile based on the vehicle speed, the engine speed, etc., and a conventionally known speed sensor or the like can be adopted.

  In addition, the power feeding device 38 is connected to the electric motor 12 through the first power feeding path 42 and the second power feeding path 44. Further, a first switch 46 as a first switch means is provided on the first power supply path 42, and a second switch as a second switch means is provided on the second power supply path 44. The switch 48 is provided. In the present embodiment, the power supply device 38 has a terminal (not shown) that outputs DC power input from the power supply device 16, and one terminal is connected to one power supply terminal of the electric motor 12. The lead wire connected to the other terminal is branched and connected to the first switch 46 and the second switch 48, respectively, so that the first feeding path 42 and the second feeding path 44 are configured. Yes.

In addition, a first diode 50 as a first rectifier is disposed on the first power supply path 42. By the rectifying action of the first diode 50, Oite the first feed path 42, together with the energization in a direction towards the power supply device 38 side from the side the first switch 46 is allowed, the power supply device 38 side To the first switch 46 is prevented from being energized. As a result, in the first power supply path 42, only DC power having a polarity that causes the movable member 28 to be driven and displaced downward is supplied to the electric motor 12.

Furthermore, a second diode 52 as a second rectifier is disposed on the second power supply path 44. This rectification of the second diode 52, Oite the second feed path 44, together with the energization in a direction towards the second switch 48 side from the power supply apparatus 38 side is permitted, the second switch Energization in the direction from the 48 side toward the power feeding device 38 side is blocked. As a result, in the second power supply path 44, only DC power having a polarity that drives and displaces the movable member 28 upward is supplied to the electric motor 12.

  As the first and second diodes 50 and 52, a diode having a known rectifying action (for example, a pn junction diode) formed using silicon, germanium, selenium, or the like as a material can be employed. There is preferably a silicon diode.

  In addition, the polarity of the DC power input from the power supply device 16 is controlled by the power supply device 38, and the first and second diodes 50, 44 are provided on the first and second power supply paths 42 and 44. By providing 52, the DC power whose polarity is controlled is supplied to the electric motor 12 selectively through one of the power supply paths 42 and 44. As is clear from this, in the present embodiment, the power feeding device 38 and the first and second diodes 50 and 52 constitute switching means for switching the polarity of the DC power fed to the electric motor 12. Yes.

  Then, the switching means having the power feeding device 38 and the first and second diodes 50 and 52 switches the polarity of the DC power fed to the electric motor 12 so that the driving direction of the movable member 28 can be switched. It has become.

  The first switch 46 provided on the first power supply path 42 includes a first electrode 54 and a first contact fitting 56 as a first brush. The first electrode 54 is formed of a conductive metal material, has a thin longitudinal plate shape, and is connected to a terminal of the power feeding device 38 via a conducting wire. In the present embodiment, the first electrode 54 is fixed to the inner peripheral surface of the holding cylinder portion 24 and is disposed so as to extend in the axial direction that is the operation direction of the movable member 28.

  The first contact fitting 56 is formed of a conductive metal material, has a rod shape, and is attached to the movable member 28. Further, the first contact fitting 56 is provided at a position corresponding to the first electrode 54 in the circumferential direction under the fitting of the movable member 28 to the holding cylinder portion 24. Further, the distal end portion of the first contact metal fitting 56 is brought into contact with the first electrode 54 when the movable member 28 is positioned in the region from the intermediate portion to the upper end in the operation direction.

  On the other hand, the second switch 48 includes a second electrode 58 and a second contact fitting 60 as a second brush. The second electrode 58 is formed of a conductive metal material, has a thin longitudinal plate shape, and is connected to a terminal of the power feeding device 38 via a conducting wire. Further, in the present embodiment, the second electrode 58 is fixed to the inner peripheral surface of the holding cylinder portion 24 and is disposed so as to extend in the axial direction that is the operation direction of the movable member 28.

  The second contact fitting 60 is made of a conductive metal material, has a rod shape, and is attached to the movable member 28. Further, the second contact fitting 60 is provided at a position corresponding to the second electrode 58 when the movable member 28 is fitted to the holding cylinder portion 24. Further, the distal end portion of the second contact fitting 60 is brought into contact with the second electrode 58 when the movable member 28 is positioned in the region from the intermediate portion to the lower end in the operation direction.

  The first contact fitting 56 and the second contact fitting 60 as described above are attached to the movable member 28 by the fixing fitting 62. The fixing metal fitting 62 is a thin plate-like metal fitting, and is formed of a conductive material. Further, the fixing bracket 62 has a curved plate shape corresponding to the outer peripheral surface shape of the movable member 28, and one surface is overlapped and fixed to the outer peripheral surface of the movable member 28, and the other surface is fixed to the other surface. The base end portions of the first contact fitting 56 and the second contact fitting 60 are fixed so as to be separated from each other by a predetermined distance in the circumferential direction of the movable member 28. As a result, the first contact fitting 56 and the second contact fitting 60 are spaced apart from each other in the direction perpendicular to the axis, and project from the peripheral wall portion of the movable member 28 toward the outer peripheral side. In the present embodiment, the first contact metal fitting 56 and the second contact metal fitting 60 extend so as to be gradually inclined downward toward the projecting tip side.

  Further, the fixing bracket 62 is connected to the other power supply terminal of the electric motor 12 through a conductive wire, and the other terminal of the power supply device 38 is connected to the electric motor 12 through the first switch 46 and the second switch 48. Is connected to the other power supply terminal.

  Here, since the first contact metal fitting 56 and the second contact metal fitting 60 are attached to the movable member 28, the first electrode 54 and the second electrode metal fitting 54 according to the reciprocating operation in the axial direction of the movable member 28. It is displaced relative to the second electrode 58 in the axial direction.

  Further, in the present embodiment, as shown in FIGS. 4 to 6, the first electrode 54 and the second electrode 58 are disposed so as to be relatively shifted in the axial direction, and the first contact fitting is provided. 56 and the tip of the second contact fitting 60 are positioned at the same height in the axial direction. More specifically, the upper end portion of the first electrode 54 is positioned axially above the upper end portion of the second electrode 58, and the lower end portion of the second electrode 58 is the first electrode 54. It is located in the lower side in the axial direction than the lower end portion. In the present embodiment, the lengths of the first electrode 54 and the second electrode 58 in the mount axis direction are equal, and the first electrode 54 extends upward from the second electrode 58. The portion and the portion of the second electrode 58 that extends downward from the first electrode 54 have the same length in the axial direction.

  As a result, the connection and disconnection of the first switch 46 and the second switch 48 are switched according to the drive displacement of the movable member 28.

  That is, in a state where the movable member 28 is drivingly displaced in the intermediate portion in the operation direction, the tip portion of the first contact fitting 56 is in contact with the first electrode 54 as shown in FIG. While being maintained in a state, the tip portion of the second contact fitting 60 is maintained in contact with the second electrode 58. In other words, the first and second contact fittings 56 and 60 are brought into sliding contact with the first and second electrodes 54 and 58 when the movable member 28 is driven and displaced in the intermediate portion in the operation direction. . Thereby, both the first switch 46 and the second switch 48 are connected, and both the first power supply path 42 and the second power supply path 44 are maintained in the connected state.

  Further, in the state where the movable member 28 is positioned at the lower end in the operation direction, the tip portion of the first contact fitting 56 displaces the first electrode 54 downward as shown in FIG. Thus, the contact state between the first electrode 54 and the first contact fitting 56 is released. Furthermore, since the second electrode 58 extends below the first electrode 54, the second electrode 58 and the second contact fitting 60 are maintained in a connected state. As a result, the first switch 46 is in a disconnected state, the tip of the second contact fitting 60 is brought into contact with the lower end of the second electrode 58, and the second switch 48 is Stay connected. Accordingly, the first power supply path 42 having the first switch 46 on the path is cut off, and the second power supply path 44 having the second switch 48 on the path is maintained in the connected state.

  On the other hand, in the state where the movable member 28 is positioned at the upper end in the operation direction, the tip of the second contact fitting 60 displaces the second electrode 58 upward as shown in FIG. Thus, the contact state between the second electrode 58 and the second contact fitting 60 is released. Further, since the first electrode 54 extends below the second electrode 58, the first electrode 54 and the first contact fitting 56 are maintained in a connected state. As a result, the second switch 48 is in a disconnected state, the tip of the first contact fitting 56 is brought into contact with the upper end of the first electrode 54, and the first switch 46 is Stay connected. Accordingly, the second power feeding path 44 having the second switch 48 on the path is blocked, and the first power feeding path 42 having the first switch 46 on the path is maintained in the connected state.

  In particular, in the present embodiment, the first electrode 54 and the second electrode 58 are set to have a sufficiently large deviation in the axial direction, and the movable member 28 is positioned at the lower end in the operation direction. The first electrode 54 is in a state where the electrode 58 extends below the contact portion between the second electrode 58 and the second contact fitting 60 and the movable member 28 is positioned at the upper end in the operation direction. Extends above the contact portion between the first electrode 54 and the first contact fitting 56. Accordingly, it is possible to effectively prevent both the first and second switches 46 and 48 from being disconnected due to an error in the displacement amount of the movable member 28 due to an inertial force or the like.

  In this case, when the movable member 28 is located in the middle part of the operation direction and both the first switch 46 and the second switch 48 are connected, the first power supply path 42 and the second power supply path 42 are connected. Electric power is supplied to the electric motor 12 through one of the power supply paths 44. That is, the first diode 50 is disposed on the first power supply path 42, and only the DC power having the polarity that drives the movable member 28 downward is supplied to the electric motor 12 through the first power supply path 42. In addition, the second diode 52 is disposed on the second power supply path 44, and only the DC power having the polarity that drives the movable member 28 downward is supplied to the electric motor 12 through the second power supply path 44. This is because power is supplied.

  When the movable member 28 is driven downward and reaches the lower end in the operation direction, the contact state between the first electrode 54 and the first contact fitting 56 is released, and the first switch 46 is shut off. . As a result, power supply to the electric motor 12 through the first power supply path 42 is stopped, and the downward displacement driving of the movable member 28 is stopped.

  On the other hand, in the state where the movable member 28 is positioned at the lower end in the operation direction as described above, the second electrode 58 and the second contact fitting 60 are maintained in contact with each other, and the movable member 28 is driven upward. The polarized DC power can be supplied to the electric motor 12 through the second power supply path 44.

  Then, the DC power having a polarity that drives the movable member 28 upward by the power supply device 38 is supplied to the electric motor 12 through the second power supply path 44, so that the movable member 28 is driven to displace upward. It is like that.

  Furthermore, when electric power is supplied to the electric motor 12 through the second power supply path 44, the movable member 28 is driven and displaced upward, and when the movable member 28 reaches the upper end in the operation direction, the second electrode 58 and The contact state of the second contact fitting 60 is released and the second switch 48 is shut off. As a result, power supply to the electric motor 12 through the second power supply path 44 is stopped, and the upward displacement drive of the movable member 28 is stopped.

  When the movable member 28 is driven and displaced upward from the lower end in the operation direction, the separated first electrode 54 and the first contact fitting 56 are brought into contact again, and the first switch 46 is turned on. Connected. Further, the first electrode 54 and the first contact metal fitting 56 are maintained in a connected state under the state where the movable member 28 is positioned at the upper end in the operation direction. Therefore, in a state where the movable member 28 is positioned at the upper end in the operation direction, the first switch 46 is maintained in the connected state, and power can be supplied to the electric motor 12 through the first power supply path 42. ing.

  Then, the DC power having a polarity that drives the movable member 28 downward by the power supply device 38 is supplied to the electric motor 12 through the first power supply path 42, so that the movable member 28 is driven to displace downward. It is done.

  Thus, in the electric actuator 10 according to the present embodiment, the reciprocating operation of the movable member 28 is realized with a target stroke. In particular, the physical contact between the first and second electrodes 54 and 58 and the first and second contact fittings 56 and 60 is automatically released by the drive displacement of the movable member 28, so that the movable member 28. Therefore, the movable member 28 can be reliably stopped at a predetermined position, and the displacement amount of the movable member 28 can be controlled with high accuracy.

  Moreover, in the present embodiment, one of the first switch 46 and the second switch 48 is shut off while the movable member 28 is positioned at the end in the operation direction. The other is connected. Therefore, when the polarity is reversed by the power feeding device 38, the direct current is quickly fed to the electric motor 12 through the connection path on the side having the switch maintained in the connected state, and the movable member 28 is moved to the opposite end side. It is actuated towards. Therefore, both the stop of the movable member 28 at the driving end and the driving from the stopped state can be stably realized.

  Further, the first and second contact fittings 56 and 60 are fixed to the movable member 28, and are displaced relative to the first and second electrodes 54 and 58 in accordance with the drive displacement of the movable member 28. Accordingly, the drive end of the movable member 28 is defined by switching the connection and disconnection of the switches 46 and 48 constituted by the electrodes 54 and 58 and the contact fittings 56 and 60. Therefore, the movable member 28 can be driven with a simple structure, a small number of parts, and at a low cost compared to the case where the driving end of the movable member 28 is defined by using a sensor or the like that detects the position of the movable member 28. The edge can be defined.

  In the present embodiment, a rotation limiting mechanism that prevents relative rotation of the movable member 28 and the holding cylinder portion 24 around the central axis is provided. Thereby, it can prevent that the movable member 28 rotates with rotation of the rotating shaft 14 of the electric motor 12, and can drive-displace the movable member 28 efficiently.

The electric actuator 10 having such a structure is employed in an automobile engine mount 64 as a fluid-filled vibration isolator as shown in FIGS . The engine mount 64 includes a mount main body 66, and a first mounting bracket 68 as a first mounting member and a second mounting bracket 70 as a second mounting member are mutually connected by a main rubber elastic body 72. It has the structure connected to. The first mounting bracket 68 is attached to a power unit (not shown) which is one member constituting the vibration transmission system, and the second mounting bracket 70 is the other member constituting the vibration transmission system. By being attached to the body of the automobile, the power unit and the vehicle body are connected in an anti-vibration manner via the engine mount 64.

  More specifically, the first mounting bracket 68 is a block-shaped member formed of iron, aluminum alloy, or the like. In the present embodiment, the upper part has a circular block shape, and the lower part is upward. It is a circular block shape that gradually increases in diameter as it goes. A mounting bolt 74 that protrudes upward is integrally provided at the upper end of the first mounting bracket 68.

  On the other hand, the second mounting bracket 70 has a thin, large-diameter, generally cylindrical shape, and is a high-rigidity member formed of iron, aluminum alloy, or the like, similar to the first mounting bracket 68. In addition, an inner flange-shaped stepped portion 76 is provided at the upper end portion, and a tapered portion 78 that extends upward and gradually expands is integrally formed at the inner peripheral side end portion of the stepped portion 76. ing. Further, a flange-shaped portion 80 that extends in the direction perpendicular to the axis is formed at the upper end portion of the tapered portion 78.

  The first mounting bracket 68 and the second mounting bracket 70 are disposed on the same central axis, spaced apart from the opening side of the second mounting bracket 70 where the flange-shaped portion 80 is provided. The main rubber elastic body 72 is interposed between the first mounting metal 68 and the second mounting metal 70, and the first mounting metal 68 and the second mounting metal 70 are formed by the main rubber elastic body 72. Are interconnected.

  The main rubber elastic body 72 is formed of a thick rubber elastic body having a substantially truncated cone shape, and a large-diameter recess 82 having a hemispherical shape or a mortar-like shape that opens to the end surface is provided at the end on the large-diameter side. Is formed. The lower end portion of the first mounting bracket 68 is inserted into the end portion on the small diameter side of the main rubber elastic body 72 and vulcanized and bonded, and the outer peripheral surface of the large diameter end portion of the main rubber elastic body 72 is attached. The upper end portion including the tapered portion 78 of the second mounting bracket 70 is overlapped and vulcanized and bonded. As a result, the first mounting bracket 68 and the second mounting bracket 70 are elastically connected by the main rubber elastic body 72, and one opening of the second mounting metal 70 is fluid-tight by the main rubber elastic body 72. Is blocked. As described above, the main rubber elastic body 72 in the present embodiment is formed as an integrally vulcanized molded product integrally including the first mounting bracket 68 and the second mounting bracket 70.

  Further, a seal rubber layer 84 having a thin-walled large-diameter cylindrical shape is integrally formed on the outer peripheral edge of the large-diameter side end of the main rubber elastic body 72 in the axially downward direction. The seal rubber layer 84 is formed on the inner peripheral surface of the second mounting bracket 70, and the inner peripheral surface of the lower portion of the second mounting bracket 70 below the stepped portion 76 is substantially covered by the seal rubber layer 84. The entire surface is covered. In addition, an annular step surface 86 that extends in a direction substantially perpendicular to the axis is formed on the inner peripheral side of the seal rubber layer 84 at the peripheral edge of the opening of the large-diameter recess 82.

A diaphragm 88 as a flexible film is disposed in the other opening of the second mounting bracket 70. The diaphragm 88 is a rubber film having a thin and large-diameter substantially disk shape, and has a sufficient slack in the axial direction on the outer peripheral portion. Further, the central portion of the diaphragm 88 is a central abutting portion 90 having a thick disc shape as compared with the outer peripheral portion. Further, an annular fixing portion 92 is integrally formed on the outer peripheral edge portion of the diaphragm 88.

  A fixing fitting 94 is vulcanized and bonded to the fixing portion 92 provided on the diaphragm 88. The fixing bracket 94 is a highly rigid member made of iron or the like, has a large-diameter, generally annular shape, and is fixed to the fixing portion 92 in an embedded state. As described above, the diaphragm 88 in the present embodiment is formed as an integrally vulcanized molded product that is integrally provided with the fixing bracket 94.

  The integral vulcanized molded product of the diaphragm 88 is attached to the integral vulcanized molded product of the main rubber elastic body 72 provided with the first mounting bracket 68 and the second mounting bracket 70. That is, after the diaphragm 88 is inserted from the opening on the opposite side of the main rubber elastic body 72 of the second mounting bracket 70, the second mounting bracket 70 is subjected to a diameter reduction process, thereby fixing the fixing bracket 94. Is fixed to the opening of the second mounting bracket 70. Thereby, the diaphragm 88 is attached so as to cover the other opening of the second attachment fitting 70 fluid-tightly.

  Under the assembly of the diaphragm 88 to the second mounting bracket 70, the body rubber elastic body 72 and the axially facing surface of the diaphragm 88 are isolated from the outside on the inner peripheral side of the second mounting bracket 70. Thus, a fluid sealing region 96 in which an incompressible fluid is sealed is formed. The incompressible fluid sealed in the fluid sealing region 96 is not particularly limited, and for example, water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixed solution thereof is preferably employed. Further, in order to effectively obtain a vibration isolation effect based on the fluid flow action described later, it is desirable to employ a low viscosity fluid having a viscosity of 0.1 Pa · s or less.

  A partition member 98 is accommodated in the fluid sealing region 96 and supported by the second mounting bracket 70. The partition member 98 includes a partition member main body 100 and a lid plate metal fitting 102.

  The partition member main body 100 has a thick, substantially disk shape, and is formed of a metal such as a hard synthetic resin or an aluminum alloy. In addition, a circular central recess 104 that opens downward is formed in the central portion of the partition member main body 100 in the radial direction. Further, a small-diameter central protrusion 106 that protrudes upward is integrally formed at the central portion in the radial direction of the partition member main body 100.

  A first circumferential groove 108 is formed on the outer peripheral edge of the partition member main body 100. The first circumferential groove 108 is opened on the outer peripheral surface of the partition member main body 100, and continuously extends the outer peripheral edge of the partition member main body 100 with a predetermined length of less than one round in the circumferential direction. Furthermore, a concave groove 110 is formed in a radially intermediate portion of the partition member main body 100. The concave groove 110 is opened at the upper end surface of the partition member main body 100 and extends continuously between the radial direction of the central recess 104 and the first peripheral groove 108 with a predetermined length of slightly less than one round in the circumferential direction. Yes. The concave groove 110 communicates with the central recess 104 through a communication passage 112 having one end extending in a direction perpendicular to the axis.

  On the other hand, the lid plate fitting 102 is a metal member having a substantially disk shape. Moreover, the outer peripheral part of the lid plate metal fitting 102 of the present embodiment is positioned axially above the center part via a step. Furthermore, a circular through hole 114 is formed in the center portion of the lid plate metal fitting 102. The through hole 114 is a small-diameter hole corresponding to the shape of the central protrusion 106 formed in the partition member main body 100.

  And the partition member 98 in this embodiment is comprised by combining these partition member main bodies 100 and the cover metal fitting 102 mutually. That is, the cover plate metal fitting 102 is superimposed on the upper end surface of the partition member main body 100, and the central protrusion 106 projecting from the partition member main body 100 is inserted into the through hole 114 formed through the cover plate metal fitting 102. By fitting, the lid plate metal fitting 102 is fixed to the partition member main body 100, and the partition member 98 is configured.

  In such a partition member 98, the partition member main body 100 and the cover plate metal fitting 102 are closely attached to each other at the central portion in the radial direction and overlapped with each other, and are positioned at a predetermined distance in the axial direction at the outer peripheral portion. Yes. A second peripheral groove 116 extending in the circumferential direction is formed between the opposing surfaces of the partition member main body 100 and the cover plate fitting 102 in the outer peripheral portion where the partition member main body 100 and the cover plate fitting 102 are separated from each other. Has been. The second circumferential groove 116 continuously extends with a predetermined length of a little less than one round in the circumferential direction, although it is not always clear in the drawing. A partition wall (not shown) formed integrally with the partition member main body 100 is provided between the circumferential end portions of the second circumferential groove 116 so that the second circumferential groove 116 has a length of slightly less than one round in the circumferential direction. Partitioning.

  Further, under the assembly of the partition member main body 100 and the cover plate fitting 102, one end of the first circumferential groove 108 and one end of the second circumferential groove 116 are one of the first circumferential grooves 108. Are connected to each other through a connection window 118 that opens to the upper end surface of the partition member main body 100. As a result, the first circumferential groove 108 and the second circumferential groove 116 form a spiral circumferential groove 120 extending in the circumferential direction with a predetermined length of slightly less than two rounds.

  Thus, the partition member 98 constituted by the partition member main body 100 and the lid plate metal fitting 102 is accommodated in the fluid sealing region 96. That is, before the diaphragm 88 is attached to the second mounting bracket 70, the partition member 98 is attached to the second mounting bracket 70 from the opening opposite to the side where the main rubber elastic body 72 is vulcanized and bonded. It is inserted. Thereafter, the diaphragm 88 is fitted into the second mounting bracket 70 from the opening, and the second mounting bracket 70 is subjected to diameter reduction processing such as an eight-way drawing, whereby the partition member 98 and the diaphragm 88 are It is fitted and fixed to the second mounting bracket 70.

  Under the arrangement of the partition member 98 and the diaphragm 88, the outer peripheral portion of the upper end surface of the partition member 98 is pressed against the step surface 86 of the main rubber elastic body 72, and the outer peripheral portion of the lower end surface of the partition member 98 is fixed to the fixing portion. The metal fittings 94 are pressed into contact with each other through 92 and sealed fluid-tightly. Further, the outer peripheral surface of the partition member 98 is fluid-tightly superimposed on the second mounting member 70 via the seal rubber layer 84. As a result, the fluid sealing region 96 is vertically divided in the axial direction across the partition member 98, and a part of the wall portion is constituted by the main rubber elastic body 72 on one side across the partition member 98. In addition, a pressure receiving chamber 122 in which pressure fluctuation is caused by elastic deformation of the main rubber elastic body 72 is formed, and a part of the wall portion is formed of a diaphragm 88 on the other side across the partition member 98. Thus, an equilibrium chamber 124 in which a volume change is allowed by elastic deformation of the diaphragm 88 is formed. The pressure receiving chamber 122 and the equilibrium chamber 124 are filled with the incompressible fluid sealed in the fluid sealing region 96, respectively.

  Further, the outer peripheral side opening of the circumferential groove 120 formed at the outer peripheral edge of the partition member 98 is fluid-tightly closed by the second mounting bracket 70. Further, one end of the circumferential groove 120 is communicated with the pressure receiving chamber 122 through a communication window (not shown) formed in the lid plate fitting 102, and the other end of the circumferential groove 120 is formed in the partition member main body 100. The equilibrium chamber 124 communicates with the communication window 126. As a result, the first orifice passage 128 as a fluid flow path extending in the circumferential direction by a predetermined length and communicating the pressure receiving chamber 122 and the equilibrium chamber 124 with each other uses the circumferential groove 120 of the partition member 98. Is formed.

  In the present embodiment, the anti-vibration effective for the low-frequency vibration around 10 Hz corresponding to the engine shake or the like based on the resonance action of the fluid flowing through the first orifice passage 128. It is tuned so that the effect (high attenuation effect) is exhibited.

  Further, the opening of the concave groove 110 formed in the partition member 98 is covered with the lid plate metal fitting 102, and one end of the concave groove 110 is communicated through a communication window (not shown) formed in the lid plate metal fitting 102. 122, and the other end of the groove 110 communicates with the equilibrium chamber 124 through the central recess 104. As a result, the second orifice passage 130 as a fluid flow path extending in the circumferential direction by a predetermined length and communicating the pressure receiving chamber 122 and the equilibrium chamber 124 with each other is formed in the concave groove 110 and the central recess of the partition member 98. 104 is used.

  The resonance frequency of the fluid that flows through the second orifice passage 130 is tuned to a higher frequency than that of the first orifice passage 128. In this embodiment, the resonance frequency corresponds to idling vibration or the like based on the resonance action of the fluid. It is tuned to exhibit an effective anti-vibration effect (low dynamic spring effect) against medium to high frequency vibrations around 20 to 40 Hz.

The tuning of the orifice passages 128 and 130 corresponds to, for example, the spring stiffness of each wall of the pressure receiving chamber 122 and the equilibrium chamber 124, that is, the amount of pressure change necessary to change the chambers 122 and 124 by a unit volume. It can be performed by adjusting the passage length and passage cross-sectional area of the orifice passages 128 and 130 while taking into consideration the characteristic values based on the respective elastic deformation amounts of the main rubber elastic body 72, the diaphragm 88, etc. The frequency at which the phase of the pressure fluctuation transmitted through the passages 128 and 130 changes to bring about a substantially resonant state can be grasped as the tuning frequency of the orifice passages 128 and 130.

  The mount body 66 according to the present embodiment having such a structure is assembled to the bracket fitting 132. The bracket fitting 132 is a highly rigid member formed of iron or the like, and has a fitting portion 134 into which the mount main body 66 is fitted. The fitting part 134 has a bottomed cylindrical shape as a whole, and has a flange part 136 at the upper end part. An annular leg 138 is fixed to the outer peripheral surface of the fitting portion 134 by welding or the like. The leg portion 138 has bolt holes (not shown) penetratingly formed at a plurality of locations on the circumference, and the leg portions 138 are screwed and fixed to the vehicle body by fixing bolts (not shown) inserted through the bolt holes. It has become.

  Then, the mount main body 66 is fitted into the fitting portion 134 of the bracket fitting 132 from the upper opening, and the second mounting fitting 70 is press-fitted and fixed to the fitting portion 134, whereby the mount main body 66 is The bracket fitting 132 is fitted and fixed. In the present embodiment, the flange-like portion 80 provided at the upper end of the second mounting bracket 70 is brought into contact with the flange portion 136 provided at the upper end of the fitting portion 134 from above, The second mounting bracket 70 and the fitting portion 134 are relatively positioned.

  Here, the electric actuator 10 having a structure according to the present invention is fitted into the fitting portion 134 of the bracket metal fitting 132 and fixed in a state where it is placed on the bottom wall portion of the fitting portion 134. The engine mount 64 according to the present embodiment is configured by mounting the mount body 66 to the bracket fitting 132 in the mounting state on the bracket fitting 132. As shown in FIGS. 7 and 8, the support member 20 constituting the electric actuator 10 has a shape corresponding to the bracket fitting 132, and the outer peripheral surface and the lower surface of the support member 20 are the bracket fitting 132. It is overlapped and fixed on the inner surface.

  In the engine mount 64, the electric actuator 10 is positioned below the mount body 66, and the movable member 28 is separated from the central contact portion 90 of the diaphragm 88 by a predetermined distance in the axial direction. Alternatively, it is positioned below in a superimposed contact state.

  In other words, the electric actuator 10 is positioned on the opposite side of the partition member 98 with the diaphragm 88 in between, and the movable member 28 of the electric actuator 10 has a second contact with the central contact portion 90 of the diaphragm 88 in between. The orifice passage 130 is opposed to the central recess 104 which is an opening portion on the equilibrium chamber 124 side.

  The movable member 28 is driven and displaced in the axial direction, so that the movable member 28 is brought into contact with or separated from the central contact portion 90 of the diaphragm 88. It can be displaced up and down according to the reciprocating operation in the axial direction. As a result, the central abutting portion 90 of the diaphragm 88 can be relatively approached or separated from the central recess 104 of the partition member 98 in accordance with the drive displacement of the movable member 28.

  That is, when the movable member 28 is positioned at the upper end in the reciprocating operation direction, the central contact portion 90 is pressed by the movable member 28 and is pressed against the lower surface of the partition member 98, so that the opening of the central recess 104 is formed. It is closed by the movable member 28 via the central contact portion 90.

  On the other hand, when the movable member 28 is positioned at the lower end in the reciprocating operation direction, the movable member 28 is separated downward with respect to the central contact portion 90 of the diaphragm 88, and the central contact portion 90 is located below the partition member 98. The central recess 104 is opened to the equilibrium chamber 124 by being spaced apart from each other.

  As described above, by controlling the reciprocating operation of the movable member 28, the opening of the central recess 104, which is the opening of the second orifice passage 130 on the equilibrium chamber 124 side, can be switched between the open state and the closed state. In this way, the communication state and the cutoff state of the second orifice passage 130 can be switched. As is clear from FIG. 8, in this embodiment, the movable member 28 and the diaphragm 88 are overlapped with each other so as to be separated from each other. Further, as is clear from the above description, in the present embodiment, the movable valve body as the action member is constituted by the movable member 28, and the output member and the action member are constituted by the same member.

  The engine mount 64 for automobiles having such a structure is such that the first mounting bracket 68 constituting the mount body 66 is mounted to a power unit (not shown) by mounting bolts 74, and the second mounting bracket. 70 is attached to a vehicle body (not shown) via a bracket fitting 132. Accordingly, the engine mount 64 is interposed between the power unit and the vehicle body, and the power unit is supported by the vehicle body in a vibration-proof manner.

  When the automobile engine mount 64 having the above-described structure is mounted on the automobile and vibrations in a low frequency range such as an engine shake which is a problem during driving are input, a relatively large pressure fluctuation occurs in the pressure receiving chamber 122. Be born. The flow amount of the fluid through the first orifice passage 128 is effectively ensured by the difference in relative pressure fluctuation generated between the pressure receiving chamber 122 and the equilibrium chamber 124, and the resonance action of the fluid or the like. Based on the fluid action, an effective anti-vibration effect (high damping effect) is exhibited against low-frequency vibration such as engine shake.

  At that time, as shown in FIG. 7, the movable member 28 is positioned at the upper end in the reciprocating operation direction, and the equilibrium chamber of the second orifice passage 130 is interposed via the central contact portion 90 of the diaphragm 88. It is pressed against the opening on the 124 side. Thereby, the opening part by the side of the equilibrium chamber 124 of the 2nd orifice channel | path 130 is obstruct | occluded fluid-tightly, and the 2nd orifice channel | path 130 is the interruption | blocking state. Accordingly, the fluid flows between the pressure receiving chamber 122 and the equilibrium chamber 124 through the second orifice passage 130, and the hydraulic pressure in the pressure receiving chamber 122 is prevented from being released to the equilibrium chamber 124. Therefore, it is possible to effectively obtain a vibration isolation effect based on the fluid flow action.

  In addition, when an idling vibration that is a problem when the vehicle is stopped or a low-frequency booming noise that is a problem when traveling is input in a medium to high frequency range, a pressure fluctuation with a small amplitude is induced in the pressure receiving chamber 122. When such vibration is input, the electric power is supplied to the electric motor 12 to cause the rotary shaft 14 to rotate in one circumferential direction, and the movable member 28 is driven and displaced downward in the axial direction as shown in FIG. It is supposed to be.

  As a result, the opening of the second orifice passage 130 on the equilibrium chamber 124 side is switched to the communication state, and the pressure receiving chamber 122 and the equilibrium chamber 124 are communicated with each other by the second orifice passage 130. The flow amount of the fluid through the second orifice passage 130 is effectively ensured by the difference in relative pressure fluctuation generated between the pressure receiving chamber 122 and the equilibrium chamber 124, and the resonance action of the fluid, etc. Based on the fluid action, an effective anti-vibration effect (low dynamic spring effect) is exerted against medium to high frequency vibrations such as idling vibrations.

  In short, in the fluid filled type vibration damping device according to the present embodiment, the second orifice passage 130 is controlled to be communicated and blocked by the reciprocating operation of the movable member 28, and the vibration damping characteristics are switched. . In FIGS. 7 and 8, the stroke of the reciprocating operation of the movable member 28 is exaggerated for easy understanding. Accordingly, the shapes of the male screw member 18 and the female screw portion 34, specifically, for example, the inclination and size of the thread in the male screw member 18 and the female screw portion 34 are exaggerated.

  In the automotive engine mount 64 having the structure according to this embodiment, the opening / closing control of the second orifice passage 130 is enhanced by employing the electric actuator 10 having the structure as described above as the driving means of the movable member 28. This can be realized with high accuracy, and switching control with stable anti-vibration characteristics becomes possible.

  In addition, since the control circuit 36 that controls the reciprocating operation of the movable member 28 has a simple structure, it is possible to prevent an increase in the number of parts and an increase in cost.

  Furthermore, by adopting a screw structure as a power conversion mechanism that converts the rotational driving force exerted by power feeding to the electric motor 12 into a linear reciprocating driving force in the axial direction and transmits it to the movable member 28, The holding force is exerted on the movable member 28 by the screwing action (the locking force or frictional force between the screw threads) of the male screw member 18 and the female screw portion 34. Therefore, the movable member 28 can be held at the drive end even in a state where the movable member 28 where the energization to the electric motor 12 is stopped is located at the drive end. The switching state can be maintained.

  In particular, when the movable member 28 is positioned at the upper end in the reciprocating operation direction, an effective holding force can be easily obtained without energization, so that the second orifice passage 130 is substantially blocked. The state can be reliably maintained, and the desired vibration-proof performance can be realized when inputting low-frequency vibration corresponding to engine shake or the like.

  Moreover, in the engine mount 64 structured to exert a holding force on the movable member 28 using friction and engagement between the male screw member 18 and the female screw portion 34, the second orifice is maintained by maintaining a continuous energized state. Compared with the case where the passage 130 is maintained in the shut-off state, even when the pressure in the pressure receiving chamber 122 is exerted on the movable member 28 through the second orifice passage 130, the movable member 28 resists the pressure. Therefore, the substantial shut-off state of the second orifice passage 130 is more reliably realized.

  Furthermore, since the holding force can be exerted on the movable member 28 without requiring the electric motor 12 to be energized, it is possible to suppress the power consumed when maintaining the switched anti-vibration characteristics, and in the energized state. Heat generation due to continuous maintenance can be suppressed and deterioration of durability due to heat can be prevented.

  Further, the movable member 28 is attached to the rotary shaft 14 by screwing the male screw member 18 fixed to the rotary shaft 14 into the female screw portion 34 formed using the central hole of the movable member 28. Therefore, it is possible to prevent relative inclination between the movable member 28 and the rotary shaft 14, and disconnection in the axial direction. Accordingly, the stable operation of the movable member 28 can be realized, and the vibration-proof characteristic can be switched with high accuracy and stability.

  Further, for example, compared to a case where a linear motor or the like is used to control the stroke in the driving direction of the movable member 28, a change in the drive displacement amount of the movable member 28 due to fluctuations in the supply voltage to the electric motor 12 is suppressed. Therefore, switching of the vibration proof characteristics can be realized with higher accuracy.

  In the present embodiment, the pressing flange portion 30 that extends to the outer peripheral side is integrally formed at the upper end portion of the movable member 28. As a result, a large area of the upper end surface of the movable member 28 is ensured, and the pressure per unit area exerted on the central contact portion 90 of the diaphragm 88 can be suppressed. In addition, since the outer peripheral surface of the pressing flange portion 30 is an arcuate curved surface, when the pressing force by the movable member 28 is exerted on the diaphragm 88, the pressing force is concentrated locally and acts. Can be prevented, and the durability of the diaphragm 88 can be improved.

  As mentioned above, although one Embodiment of this invention has been described, this is an illustration to the last, Comprising: This invention is not limited at all by the specific description in this Embodiment.

  For example, in the embodiment, the first and second electrodes 54 and 58 are attached to the holding cylinder portion 24 side, and the first and second contact fittings 56 and 60 are attached to the movable member 28 side. The first and second contact fittings 56 and 60 are displaced relative to the first and second electrodes 54 and 58 in accordance with the drive displacement of the movable member 28. However, this is only an example. For example, the first and second electrodes 54 and 58 are attached to the outer peripheral surface of the movable member 28, and the first and second contact fittings 56 and 60 are held by the holding cylinder. It may be attached to the inner peripheral surface of the portion 24.

  Moreover, in the said embodiment, while the edge part of the 1st electrode 54 and the 2nd electrode 58 has mutually shifted in the axial direction, the front-end | tip part of the 1st contact metal fitting 56 and the 2nd contact metal fitting 60 is a shaft. For example, the axial end portions of the first electrode 54 and the second electrode 58 are aligned with each other in the axial direction, and the first contact fitting 56 is arranged. When the movable member 28 is positioned at the end in the operation direction by positioning the tip portions of the second contact fitting 60 and the second contact fitting 60 in the axial direction, the first and second switches 46 and 48 Either one can be cut off, and the other can be kept connected.

  Further, it is not essential that one of the first and second electrodes 54 and 58 and the first and second contact fittings 56 and 60 is attached to the movable member 28. For example, a rotating member as a power transmission member that is rotated according to the rotation of the rotating shaft 14 and has a reduced number of rotations compared to the rotating shaft 14 through a reduction gear train or the like is provided separately from the output member. The first and second brushes are mounted on the outer peripheral surface of the rotating member, and the first and second extending in the rotation direction of the rotating member are located at positions corresponding to the tip portions of the first and second brushes. Two electrodes are disposed. Further, the contact portions of the first and second brushes with the electrodes are arranged at the same position in the circumferential direction, and the end portions of the first and second electrodes are positioned so as to be displaced from each other in the rotation direction of the rotating member. . When the rotating member is rotated by a certain amount, one of the first and second switch means is cut off, and the other is maintained in the connected state, so that the displacement of the output member is reduced. It may be specified.

  As is clear from the above description, the relative displacement between the first and second electrodes and the first and second brushes is not necessarily limited to the relative displacement in the drive direction of the output member. The contact state and non-contact state of the electrode and the brush are switched by relative displacement caused by rotation around the center line of the reciprocating operation of the output member or linear relative displacement in a direction different from the reciprocating operation direction of the output member. It may be like this.

  In the embodiment, the switching means for switching the polarity of the DC power supplied to the electric motor 12 includes the first and second diodes 50 and 52. However, the switching means is not necessarily the first. The second diodes 50 and 52 may not be included, and the first power supply path 42 and the second power supply path 44 may supply direct-current power having different polarities to the electric motor 12. good. Specifically, for example, mechanical switch means for switching one of the first power supply path 42 and the second power supply path 44 to a cut-off state according to the polarity of the DC power supplied to the electric motor 12. By providing separately from the first and second switches 46 and 48, a rectifying means such as a diode can be omitted.

  In the embodiment, as an example of the power conversion mechanism, a screw structure including the male screw member 18 attached to the rotary shaft 14 and the female screw portion 34 provided on the movable member 28 is shown. The power conversion mechanism is not limited to such a screw structure. For example, a worm gear structure can be adopted as the power conversion mechanism.

  More specifically, for example, in the automobile engine mount 140 shown in FIG. 9, a predetermined length in the circumferential direction with respect to the outer peripheral surface of the movable member 144 constituting the electric actuator 142. A gear portion 146 is formed by engraving the thread. In the following description, members and parts that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  Then, the male screw member 18 fixed to the rotating shaft 14 of the electric motor 12 is screwed to the gear portion 146 provided on the movable member 144. As a result, the worm gear structure as the power conversion mechanism includes the male screw member 18 and the gear portion 146, and when the electric motor 12 is supplied with power, the rotational driving force of the rotating shaft 14 is linear with the worm gear structure. It is converted into a reciprocating driving force and transmitted to the movable member 144.

As described above, by adopting a worm gear structure in which the male screw member 18 is screwed to the gear portion 146 at a part of the circumference, the output member and the power can be obtained by using the rotational driving force of the electric motor 12 as a linear driving force. A power conversion mechanism for transmitting to the movable member 144 that is a transmission member can be realized.

  Further, in the engine mount 64 according to the embodiment, the movable valve body as the action member for switching the communication state and the cutoff state of the second orifice passage 130 is provided by the movable member 28 as the output member constituting the electric actuator 10. Although it is configured, for example, an action member that switches between the communication state and the cutoff state of the fluid flow path is provided separately from the output member, and the action member is connected to the output member via a rack or the like, Alternatively, by directly fixing, the reciprocating driving force exerted on the output member may be transmitted to the action member. Also by this, the action member is driven to reciprocate with the reciprocating drive of the output member, so that the fluid flow path switching control can be effectively realized.

  The electric actuator according to the present invention has an output member that can be reciprocated linearly. For example, the connection and blocking of the fluid flow path can be switched or an external force can be applied to other members or parts. The action member for exerting the effect is not essential, and the action member may be provided separately from the output member and retrofitted.

  The engine mount 64 shown in the above embodiment is a specific example of the fluid filled type vibration isolator according to the present invention, and the fluid filled type according to the present invention has the specific structure described in the above embodiment. The structure of the vibration isolator is not limitedly interpreted. For example, the engine mount 64 according to the embodiment includes the first orifice passage 128 and the second orifice passage 130, but three or more orifice passages may be provided. In addition, for example, a movable plate or a movable film that is formed of a rubber elastic body and separates the pressure receiving chamber and the equilibrium chamber is provided, and the hydraulic pressure in the pressure receiving chamber is changed to the equilibrium chamber by minute displacement or minute deformation of the movable plate or movable film. A hydraulic pressure absorbing mechanism for transmission can also be provided.

  In the above embodiment, the power supply device 16 is shown as a power supply means to the electric motor 12, but the electric actuator according to the present invention may include a power supply means for supplying power to the electric motor in advance. A power feeding means is prepared separately from the electric actuator, and the electric actuator itself may have a structure not including the power feeding means.

  Further, the present invention is not necessarily applied only to the electric actuator for the fluid filled type vibration isolator, but can be applied to the electric actuator for various uses that require a linear reciprocating driving force. is there.

  Further, the fluid-filled vibration isolator according to the present invention is not necessarily employed only as an engine mount, and can be employed as a mount other than the engine, such as a body mount and a member mount. The present invention can be applied to a vibration isolator for various uses.

  Furthermore, the fluid-filled vibration isolator according to the present invention is not necessarily applied only to the fluid-filled vibration isolator for automobiles, and is applicable to, for example, engine mounts and member mounts for trains. Also, it can be suitably employed as a fluid-filled vibration isolator for various other uses.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

It is sectional drawing which shows the electric actuator as one Embodiment of this invention, Comprising: It is the II sectional view taken on the line of FIG. In the electric actuator, II-II line sectional view of FIG. 3 showing a state where the movable member is positioned below end. III-III sectional view taken on the line of FIG. The model figure of the electric actuator which comprises the engine mount. The model figure which shows the state in which a movable member is located in a lower end in the electric actuator. The model figure which shows the state in which the movable member is located in an upper end in the electric actuator. Sectional drawing of the engine mount provided with the electric actuator. Sectional drawing which shows the state in which the 2nd orifice channel | path was connected in the engine mount. Sectional drawing which shows the engine mount as another embodiment of this invention.

Explanation of symbols

10: Electric actuator, 12: Electric motor, 14: Rotating shaft, 18: Male screw member, 28: Movable member, 34: Female screw part, 38: Power supply device, 42: First power supply path, 44: Second power supply Path: 46: first switch, 48: second switch, 50: first diode, 52: second diode, 54: first electrode, 56: first contact fitting, 58: second switch Electrode, 60: second contact fitting, 64: engine mount, 68: first attachment fitting, 70: second attachment fitting, 72: main rubber elastic body, 88: diaphragm, 122: pressure receiving chamber, 124: equilibrium Chamber, 128: first orifice passage, 130: second orifice passage

Claims (5)

In the electric actuator having an output member that is linearly reciprocated by converting the rotational driving force of the electric motor driven by DC power into a linear driving force via a power conversion mechanism,
Switching means for switching the polarity of the DC power supplied to the electric motor is provided, and the rotation direction of the electric motor is changed by the switching operation of the switching means so that the driving direction of the output member is forward and backward. While being able to switch
A first electrode that is relatively displaced in contact with the displacement of the output member and a first electrode are disposed on a first power supply path for supplying the electric motor with DC power having a polarity for driving the output member in the forward direction. First switch means having one brush is provided, the first brush is detached from the first electrode, the contact state is released, and the first power supply path is cut off, thereby the output. The displacement end of the member in the forward direction is defined,
A second electrode that is relatively displaced in contact with the displacement of the output member and a second electrode are provided on the second power supply path for supplying the electric motor with DC power having a polarity for driving the output member in the backward direction. Second switch means having two brushes is provided, and the second brush is detached from the second electrode, the contact state is released, and the second power feeding path is cut off, so that the output The displacement end of the member in the backward direction is defined,
Further, the second switch means is maintained in the connected state at the cutoff position of the first switch means, and the first switch means is maintained in the connected state at the cutoff position of the second switch means. On the other hand,
At least one of a screw structure and a worm gear structure is provided on a transmission path of driving force from the electric motor to the output member, and the rotational driving force of the electric motor is transmitted to the output member as a reciprocating driving force. The power conversion mechanism is configured to include at least one of the screw structure and the worm gear structure, and the first power supply path is blocked and the displacement end of the output member in the forward direction is defined. The output member is held at the displacement end by the meshing action of the threads in the power conversion mechanism when the two power supply paths are blocked and the displacement end of the output member in the backward direction is defined. electric actuator, characterized in that has become.   A first DC power that allows the electric power to be fed to the electric motor with the polarity of the DC power that drives the output member in the forward direction, and the electric power that is fed to the electric motor that has the polarity to drive the output member in the backward direction. A rectifying means is provided on the first power supply path, and allows the direct current power of the polarity that drives the output member in the backward direction to be fed to the electric motor, and drives the output member in the forward direction. A second rectifying means for blocking the supply of polarity direct-current power to the electric motor is provided on the second power supply path, and includes the first rectifying means and the second rectifying means. The electric actuator according to claim 1, wherein the means is configured. The power conversion mechanism includes a power transmission member, and any one of the first electrode, the second electrode, the first brush, and the second brush is provided on the power transmission member. The first electrode and the second electrode are disposed so as to extend in the operation direction of the power transmission member with respect to the reciprocating operation of the output member, and the first electrode and the second electrode are disposed in the operation direction of the power transmission member. While the end of one electrode and the end of the second electrode are offset from each other, the first brush and the second brush are provided at the same position in the operating direction of the power transmission member. The electric actuator according to claim 1 or 2.   One of the first electrode, the second electrode, the first brush, and the second brush is provided on the output member, and the first electrode and the second electrode are The first and second electrodes are provided so as to extend linearly in the reciprocating direction of the output member, and the ends of the first electrode and the second electrode are displaced from each other in the reciprocating direction of the output member. 4. The electric actuator according to any one of 3. The first mounting member and the second mounting member are connected by a main rubber elastic body, and a pressure receiving chamber in which a part of a wall portion is configured by the main rubber elastic body and incompressible fluid is enclosed, and a flexible In a fluid-filled vibration isolator in which a part of the wall portion is formed of a conductive film to form an equilibrium chamber in which an incompressible fluid is enclosed, and the pressure receiving chamber and the equilibrium chamber communicate with each other by a fluid flow path.
5. A fluid, wherein the fluid passage is switched between a communication state and a shut-off state by reciprocating driving of the output member constituting the electric actuator according to any one of claims 1 to 4. Enclosed vibration isolator.

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