JP6699356B2 - Overrunning clutch - Google Patents

Description

  The present invention relates to an overrunning clutch.

  Conventionally, there is known an overrunning clutch that is provided between an inner ring and an outer ring and switches between an engaged state and a released state in accordance with a rotational speed difference between the two. Such an overrunning clutch is, for example, in an engaged state when the outer wheel is relatively clockwise and in a released state when it is counterclockwise.

  For example, Patent Document 1 discloses a two-way clutch capable of switching the engagement/release direction. A wedge space is formed between the outer ring and a rotary shaft provided on the inner peripheral side of the outer ring, and rollers are arranged in the wedge space. The engagement/disengagement direction can be changed by variously changing the arrangement of the wedge space, especially the part (disengagement part, idling part) and narrow part (engagement part) wider than the diameter of the roller, such as counterclockwise or clockwise. Can be changed. For example, by setting a portion wider than the diameter of the roller as the end portion on the counterclockwise side of the wedge space, the counterclockwise direction can be the release direction.

JP-A-5-302632

  By the way, once the engaging members such as the rollers and the tops are brought into the engaged state (engaged state), basically, the relative state of the inner ring and the outer ring is not switched to the released state unless the relative rotation is switched. If it is attempted to interrupt the driving force transmission between the inner ring and the outer ring while the relative rotation between the inner ring and the outer ring is not switched due to abnormal rotation or the like, the engaging member in the engaged state is forced to move in the direction opposite to the engaging direction. Need to be pulled out. At this time, in order to pull out the engaging member, a large force such as a force equal to or larger than the transmission torque is required, but at that time, the engaging member and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring meshing with the engaging member are damaged. There is a risk. Therefore, it is an object of the present invention to provide an overrunning clutch capable of switching an engaged state of an engaging member in an engaged state to a released state with a force lower than a transmission torque.

  The overrunning clutch according to the present invention includes an outer ring, an inner ring, an engaging member, and a separating member. The engagement member can engage the inner ring and the outer ring. The separating means can separate the engaging surface of the engaging member in the vertical direction from the engaging surface of at least one of the outer ring and the inner ring when the engaging member is engaged with the outer ring and the inner ring. Is.

  In the above invention, the overrunning clutch may include a biasing unit and a control unit. In this case, the control means causes the biasing means to bias the engaging means in a direction opposite to the engaging direction, and the separating means causes the engaging surface of the engaging member to contact at least the outer ring and the inner ring. The second control for separating the one engagement surface in the vertical direction can be executed sequentially or simultaneously.

  Further, in the above invention, the separating means may separate the engaging member from the inner ring or the outer ring by contracting the engaging member toward the outer ring or the inner ring.

  Further, in the above invention, the spacing means is at least one of a means for displacing the engagement surface of the outer ring in a direction away from the inner ring and a means for displacing the engagement surface of the inner ring in a direction away from the outer ring. You can

  Further, in the above invention, the separating means may be configured to include a magnetostrictive element.

  Further, in the above invention, the separating means may be configured to include a piezoelectric element. In this case, a plurality of engaging members are provided, and only one piezoelectric element is provided in any one of the inner ring, the outer ring, and the engaging member, and the piezoelectric element is the inner ring, the outer ring, the engaging member, and the entire overrunning clutch. It can vibrate at any natural frequency.

  Further, in the above invention, the urging means may be composed of at least one of the elastic member and the electromagnet.

  According to the present invention, it is possible to switch the engagement state of the engagement member in the engagement state to the release state with a force lower than the transmission torque.

It is a figure which illustrates a partial structure of the overrunning clutch (sprag type) concerning this embodiment. It is a figure explaining the switching process from an engagement state of an overrunning clutch (sprag type) concerning this embodiment to a release state. It is a figure which shows another example of the overrunning clutch (sprag type) which concerns on this embodiment. It is a figure which shows another example (roller clutch type) of the overrunning clutch which concerns on this embodiment. It is a figure explaining the change process from an engagement state to a release state of another example (roller clutch type) of an overrunning clutch concerning this embodiment. It is a figure which shows another example of the overrunning clutch which concerns on this embodiment. It is a figure explaining the switching process from the engagement state to the release state of another example of the overrunning clutch concerning this embodiment.

<First Embodiment>
FIG. 1 illustrates an overrunning clutch 10 according to this embodiment. The overrunning clutch 10 shown in FIG. 1 is a sprag type clutch and includes an inner ring 12, an outer ring 14, a sprag cam 16, a support ring 18, a spring 20, and an electromagnet 22.

  The outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14 are separated from each other, and the sprag cam 16, the support ring 18, the spring 20, and the electromagnet 22 are arranged in the separated space. When the sprag cam 16 is engaged (engaged) between the outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14, torque is transmitted between the inner ring 12 and the outer ring 14 via the sprag cam 16. It That is, the outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14 together form an engaging surface.

  The sprag cam 16 is an engagement member provided in plural numbers along the circumferential direction on a support ring 18 formed concentrically with the inner ring 12 and the outer ring 14. The sprag cam 16 is rotatably supported by the support ring 18. In the example shown in FIG. 1, when the outer race 14 rotates clockwise relative to the inner race 12, the sprag cam 16 rotates clockwise and is bitten by the inner race 12 and the outer race 14 (engagement state). . On the other hand, when the outer ring 14 rotates counterclockwise relative to the inner ring 12, the sprag cam 16 rotates counterclockwise and separates from the inner ring 12 and the outer ring 14 (released state).

  The sprag cam 16 includes a magnetostrictive element 28 and a weight 30. As will be described later, when the magnetism is applied, the magnetostrictive element 28 is deformed, whereby the sprag cam 16 is separated from the inner ring 12 and the outer ring 14. The magnetostrictive element 28 is made of, for example, a material in which iron (Fe) and a rare earth element such as terbium (Tb) or dysprosium (Dy) are mixed. The magnetostrictive element 28, including this embodiment and other examples thereafter, is included in the spacing member in the claims. The electromagnet 22 is included in the biasing means in the claims.

  The weight 30, which serves as a magnetic path between the electromagnet 22 and the magnetostrictive element 28, is preferably made of a magnetically permeable member. In addition, the weight 30 is preferably made of a magnetic material that is attracted to the magnetic force of the electromagnet 22. For example, the weight 30 is made of iron, nickel, or an alloy thereof.

  The spring 20 is an elastic member that biases the sprag cam 16 in the engagement direction. In the example of FIG. 1, the spring 20 is provided on the inner ring 12 side and biases the sprag cam 16 in the clockwise direction.

  The electromagnet 22 faces the sprag cam 16 and applies magnetism to the magnetostrictive element 28 of the sprag cam 16. Moreover, the weight 30 of the sprag cam 16 is attracted by the magnetism. The electromagnet 22 is provided, for example, at the tip of a column 32 that extends radially from the inner ring 12. A current source 31 (see FIG. 2) provided in the inner ring 12 or the like supplies a current to the electromagnet 22.

  FIG. 2 illustrates a schematic diagram when the overrunning clutch 10 according to the present embodiment is switched from the engaged state to the released state. In this example, the outer ring 14 is assumed to be rotating clockwise (engagement direction) relative to the inner ring 12. Further, as an initial state, the overrunning clutch 10 is in an engaged state, that is, the engagement surface of the sprag cam 16 is engaged with the outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14.

  After the initial state, for example, when current is supplied to the electromagnet 22 from the current source 31 provided in the inner ring 12, magnetic flux is generated from the electromagnet. The magnetic flux forms a loop path L (magnetic path) of the weight 30 of the sprag cam 16, the magnetostrictive element 28, the inner ring 12, the support column 32, and the electromagnet 22. At this time, by applying magnetism to the magnetostrictive element 28, the magnetostrictive element 28 contracts in at least one of the outer ring direction and the inner ring direction. In FIG. 2, an example in which the magnetostrictive element 28 contracts toward the center of rotation is shown by a broken line.

  As the magnetostrictive element 28 contracts, the engagement surface 34 of the sprag cam 16 is vertically separated from the engagement surfaces 24 and 26 of at least one of the inner ring 12 and the outer ring 14. This causes the overrunning clutch 10 (more accurately, the sprag cam 16) to switch from the engaged state to the released state.

  The vertical direction does not indicate only the 90° direction with respect to the engagement surface, but includes a range that may be regarded as being substantially vertical. For example, in consideration of mechanical accuracy and tolerance, a range of 85° or more and 95° or less may be included in the vertical direction.

  When switching the sprag cam 16 from the engaged state to the released state, if the sprag cam 16 is to be pulled out from the inner ring 12 and the outer ring 14 in parallel with the engagement surface 34 and separated from each other, the gap between the inner ring 12 and the outer ring 14 may be reduced. In principle, the sprag cam 16 cannot be removed from the inner ring 12 and the outer ring 14 unless a force equal to or greater than the torque transmitted by the above is applied.

  On the other hand, in the present embodiment, the sprag cam 16 is separated from the inner ring 12 and the outer ring 14 perpendicularly to the engagement surfaces 34, 24, 26 of the sprag cam 16, the inner ring 12 and the outer ring 14. With such a configuration, the force required for separation can be suppressed to less than the torque transmitted between the inner ring 12 and the outer ring 14.

  In addition, in the present embodiment, the electromagnet 22 pulls the weight 30 of the sprag cam 16 to urge the sprag cam 16 in a direction opposite to the engaging direction. At this time, it is preferable that the attraction force (more accurately, the moment) by the electromagnet 22 is larger than the elastic force (more accurately, the moment) by the spring 20. By doing so, it is possible to rotate the sprag cam 16 once separated from the inner ring 12 and the outer ring 14 in the counterclockwise direction which is the release direction, and to reliably switch the overrunning clutch 10 from the engaged state to the released state. Become.

  In the embodiment illustrated in FIGS. 1 and 2, the magnetostrictive element 28 that contracts by applying magnetism is used, but the embodiment is not limited to this. It is known that the magnetostrictive element 28 has the property of expanding, while magnetism is applied, and contracting (returning to the original condition) when the magnetism is cut off, instead of the above property. Such a magnetostrictive element 28' may be used as a constituent member of the overrunning clutch 10.

  FIG. 3 illustrates the overrunning clutch 10 in which the magnetostrictive element 28 ′ is provided on the sprag cam 16. The magnetostrictive element 28' has the property of expanding while magnetism is applied and contracting (restoring) when the magnetism is interrupted.

  Further, the electromagnet 22 is provided on the engagement direction side, that is, on the clockwise upstream side of the sprag cam 16, and attracts the sprag cam 16 to urge it clockwise (engagement direction). On the other hand, the spring 20 is provided on the release direction side, that is, the counterclockwise upstream side of the sprag cam 16, and biases the sprag cam 16 counterclockwise (release direction).

  Compared to the embodiment of FIG. 1, in FIG. 1, the means for urging the sprag cam 16 in the engaging direction is the spring 20, whereas in FIG. 3, the electromagnet 22 plays its role. Further, in FIG. 1, the means for urging the sprag cam 16 in the releasing direction is the electromagnet 22, whereas in FIG. 3, the spring 20 plays the role. The magnitude relationship between the elastic force of the spring 20 and the attractive force (more precisely, the moment) of the electromagnet 22 is the elastic force of the spring 20<the attractive force of the electromagnet 22 in both FIGS.

  In such a configuration, the overrunning clutch 10 is brought into the engaged state when the outer ring 14 is rotating clockwise with respect to the inner ring 12. First, electric current is supplied to the electromagnet 22. The magnetostrictive element 28 ′ is expanded by the magnetic flux generated by the electromagnet 22, and the sprag cam 16 is attracted clockwise by the electromagnet 22. As a result, the sprag cam 16 engages with the inner ring 12 and the outer ring 14.

  When the sprag cam 16 is switched from the engaged state to the released state, the current supply to the electromagnet 22 is cut off. As a result, the magnetostrictive element 28' contracts (returns to its original state), and the engagement surface 34 of the sprag cam 16 is vertically separated from the engagement surfaces 24 and 26 of at least one of the inner ring 12 and the outer ring 14. Further, when the attraction force of the electromagnet 22 becomes zero, the sprag cam 16 is urged by the spring 20 in the releasing direction, that is, counterclockwise.

<Modification of First Embodiment>
1 to 3, the magnetostrictive elements 28 and 28' are included in the spacing member, but instead of this, a piezoelectric element and a voltage source for applying a voltage thereto may be provided. For example, instead of the magnetostrictive element 28 of FIG. 1, a voltage element that contracts when a voltage is applied may be provided. Further, instead of the magnetostrictive element 28' of FIG. 3, a voltage element that expands when a voltage is applied and contracts (returns to the original state) when the voltage is cut off may be provided. The voltage can be applied to the piezoelectric element provided on the sprag cam 16 by applying a voltage to the sprag cam 16 at the time of engagement by forming a circuit in which one of the outer ring 14 and the inner ring 12 is on the positive side and the other is on the negative side.

<Second Embodiment>
FIG. 4 shows an example of a roller clutch as another example of the overrunning clutch 10 according to the present embodiment. The overrunning clutch 10 includes an inner ring 12, an outer ring 14, a roller 36, a spring 20, an electromagnet 22, and a piezoelectric element 40. In this example, the roller 36 is included in the engagement member. The electromagnet 22 is included in the urging means, and the piezoelectric element 40 is included in the separating means.

  The outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14 are separated from each other, and the roller 36, the spring 20, and the electromagnet 22 are arranged in this separated space. Further, the space (wedge space 38) in which the roller 36, the spring 20, and the electromagnet 22 are arranged has a taper shape in which the diameter of the roller 36 is gradually reduced to become smaller than the diameter of the roller 36. Has been formed. When urging the roller 36 to a portion having a diameter equal to or larger than the diameter of the roller 36, urging is performed in the releasing direction, and when urging the roller 36 to a portion having a diameter smaller than the diameter of the roller 36, urging is applied to an engaging portion. Become.

  In the example shown in FIG. 4, the wedge space 38 is formed in a tapered shape that narrows in the clockwise direction. Therefore, when the outer ring 14 rotates clockwise with respect to the inner ring 12, the roller 36 is engaged (engaged) with the inner ring 12 and the outer ring 14. On the other hand, when the outer ring 14 rotates counterclockwise with respect to the inner ring 12, the roller 36 separates from the inner ring 12 and the outer ring 14 (released state).

  The spring 20 urges the roller 36 in the engagement direction, that is, toward the portion of the wedge space 38 where the diameter of the roller 36 is less than the diameter of the roller 36. As will be described later, the electromagnet 22 urges the roller 36 in the releasing direction, that is, toward the portion of the wedge space 38 having a diameter equal to or larger than the diameter of the roller 36.

  A piezoelectric element 40 is provided on at least one of the outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14 that define the wedge space 38. The piezoelectric element 40 is arranged such that at least a part of the wedge space 38 is included in an engaging surface with the roller 36, that is, a portion having a diameter smaller than that of the roller 36. That is, the surface of the piezoelectric element 40 (the surface exposed to the wedge space 38) functions as an engagement surface and is engaged with the roller 36.

  The roller 36 is preferably made of a magnetic material that is attracted to the magnetic force of the electromagnet 22. For example, the roller 36 is made of iron, nickel, or an alloy thereof.

  FIG. 5 illustrates a schematic diagram when the overrunning clutch 10 according to the present embodiment is switched from the engaged state to the released state. In this example, the outer ring 14 is assumed to be rotating clockwise (engagement direction) relative to the inner ring 12. In the initial state, the overrunning clutch 10 is in the engaged state, that is, the engagement surface 34 of the roller 36 is the engagement surface 24 (outer peripheral surface) of the inner ring 12 and the engagement surface 26 of the outer ring 14 (the piezoelectric element 40). Surface) of the vehicle.

  After the initial state, when voltage is applied to the piezoelectric element 40 from the voltage source 41 provided in the outer ring 14 or the like, the piezoelectric element 40 contracts in at least one of the inner ring direction and the outer ring direction. In the example shown in FIG. 5, since the piezoelectric element 40 is provided on the outer ring 14, the piezoelectric element 40 contracts to the outer ring side (outer diameter side) when a voltage is applied.

  As the piezoelectric element 40 contracts, the engagement surface 26 of the outer ring 14 is separated from the engagement surface 34 of the roller 36 in the vertical direction. In other words, the engagement surface 26 of the outer ring 14 is displaced in the direction away from the inner ring. This causes the overrunning clutch 10 (more accurately, the roller 36) to switch from the engaged state to the released state. When the piezoelectric element 40 is provided on the inner ring 12, the engagement surface 24 of the inner ring 12 is separated from the engagement surface 34 of the roller 36 in the vertical direction. In other words, the engagement surface 24 of the inner ring 12 is displaced in the direction away from the outer ring.

  In addition, in this embodiment, a current is supplied from the current source 31 to the electromagnet 22 to generate a magnetic field, and the roller 36 is attracted. That is, the roller 36 is biased in the direction opposite to the engagement direction (release direction). At this time, the attraction force of the electromagnet 22 is preferably larger than the elastic force of the spring 20.

  If the roller 36 is not pulled in the releasing direction after the piezoelectric element 40 is contracted, the roller 36 is urged by the spring 20 in the engaging direction to be pulled to a position where the piezoelectric element 40 is not arranged, and again. There is a possibility of reaching the engaged state. By performing the contraction of the piezoelectric element 40 and the pulling in the release direction at the same time as in the present embodiment, re-engagement after the release can be prevented. The pulling in the releasing direction, that is, the current supply to the electromagnet 22 may be performed prior to the voltage application to the piezoelectric element 40.

<Third Embodiment>
FIG. 6 shows another example of the overrunning clutch 10 according to the present embodiment. In this example, as the separating member, a piezoelectric element 40 is included in addition to or instead of the magnetostrictive element 28. That is, the components of the overrunning clutch 10 are deformed by the piezoelectric element 40, and thereby the engaging members are vertically separated from the engaging surfaces of the inner ring 12 and the outer ring 14.

  FIG. 6 illustrates a sprag type overrunning clutch 10. Instead of this, the present embodiment may be applied to a roller clutch type overrunning clutch 10.

  The overrunning clutch 10 shown in FIG. 6 changes the structure of the sprag cam 16 compared with the overrunning clutch 10 illustrated in FIG. That is, the magnetostrictive element 28 is removed from the sprag cam 16 and only the weight 30 of the magnetically permeable member constitutes the sprag cam 16'.

  Further, the piezoelectric element 40 is provided on at least one of the inner ring 12, the outer ring 14, and the sprag cam 16 ′ that is an engaging member of the overrunning clutch 10. In the example shown in FIG. 6, the piezoelectric element 40 is provided on the outer peripheral surface of the outer ring 14. Only one piezoelectric element 40 may be provided, but a plurality of piezoelectric elements 40 may be provided as long as they can be cooperatively operated in generating a vibration mode described later. Further, in order to simplify the control, only one piezoelectric element 40 may be provided in the overrunning clutch 10. Since the structure of the sprag cam 16' and the structure other than the piezoelectric element 40 are the same as those in the embodiment of FIG. 1, detailed description of the structure will be omitted.

  FIG. 6 shows a schematic diagram when the overrunning clutch 10 is switched from the engaged state to the released state. In this example, the outer ring 14 is assumed to be rotating clockwise (engagement direction) relative to the inner ring 12. As an initial state, the overrunning clutch 10 is in an engaged state, that is, the engagement surface of the sprag cam 16 ′ is engaged with the outer peripheral surface 24 of the inner ring 12 and the inner peripheral surface 26 of the outer ring 14.

  When an AC voltage is applied to the piezoelectric element 40 from the initial state, the piezoelectric element 40 deforms according to the voltage waveform. Along with this, the outer ring 14 to which the piezoelectric element 40 is attached also deforms. A large variation can be obtained by adjusting the displacement of the piezoelectric element 40 and causing the overrunning clutch 10 to resonate. The broken line in FIG. 6 shows the secondary vibration mode (at the time of resonance) of the outer ring 14 in the radial direction. The frequency of the voltage waveform applied to the piezoelectric element 40 may be any of the natural frequencies of the inner ring 12 alone, the outer ring 14 alone, the engagement member (sprag cam 16 ′), and the overrunning clutch 10 as a whole.

  As the amplitude of the AC voltage applied to the piezoelectric element 40 increases, the deformation amplitude of the outer ring 14 increases. Furthermore, as shown in FIG. 7, the amplitude of the outer ring 14 exceeds the threshold value Ath. The threshold value Ath indicates, for example, an amplitude to such an extent that the engagement surface 34 of the sprag cam 16 ′ in the engagement state is completely separated from the engagement surface 26 of the outer ring 14 in the vertical direction, and is acquired in advance by a test or a simulation. It is possible.

  Further, when the amplitude of the outer ring 14 exceeds the threshold value Ath, a current is supplied to the electromagnet 22 to generate magnetism, and the sprag cam 16' is biased in the releasing direction (rotates counterclockwise). Alternatively, the electric current may be supplied to the electromagnet 22 from a stage before the amplitude of the outer ring 14 exceeds the threshold value Ath. By doing so, the overrunning clutch 10 (more precisely, the sprag cam 16) can be switched from the engaged state to the released state.

  In the embodiment of FIG. 6, the engaging member is disengaged from the outer ring and the inner ring only by the deformation by the piezoelectric element 40 without utilizing the contraction or extension of the engaging member (sprag cam) by the magnetostrictive element 28. However, it is not limited to this form. For example, the piezoelectric element 40 may be applied to the overrunning clutch 10 of FIG. 1 to promote the disengagement.

10 overrunning clutch, 12 inner ring, 14 outer ring, 16 sprag cam (engaging member), 18 support ring, 20 spring, 22 electromagnet (separating means), 24 inner peripheral surface (engaging surface), 26 outer peripheral surface (Engagement surface), 28 magnetostrictive element (separation means), 30 weight, 31 current source, 32 strut, 34 engagement surface of engagement means, 36 roller, 38 wedge space, 40 piezoelectric element, 41 voltage source.

Claims (7)

Outer ring,
An inner ring,
An engagement member,
Spacing means
Biasing means,
Control means,
Equipped with
The engagement member is capable of engaging the inner ring and the outer ring,
The separating means can separate the engagement surface of the engagement member in the vertical direction from the engagement surface of at least one of the outer ring and the inner ring when the engagement member is engaged with the outer ring and the inner ring. der is,
The control means is
A first control for urging the engaging member in a direction opposite to the engaging direction by the urging means;
A second control for separating the engagement surface of the engagement member by the separation means in a direction perpendicular to at least one engagement surface of the outer ring and the inner ring;
Can be performed sequentially or simultaneously,
Overrunning clutch. Outer ring,
An inner ring,
An engagement member,
Spacing means
Equipped with
The engagement member is capable of engaging the inner ring and the outer ring,
The separating means can separate the engaging surface of the engaging member in the vertical direction from the engaging surface of at least one of the outer ring and the inner ring when the engaging member is engaged with the outer ring and the inner ring. And
The separating means contracts the engaging member toward the outer ring or the inner ring to separate the engaging member from the inner ring or the outer ring,
Overrunning clutch. Outer ring,
An inner ring,
An engagement member,
Spacing means
Equipped with
The engagement member is capable of engaging the inner ring and the outer ring,
The separating means can separate the engaging surface of the engaging member in the vertical direction from the engaging surface of at least one of the outer ring and the inner ring when the engaging member is engaged with the outer ring and the inner ring. And
The separating means is
Means for displacing the engagement surface of the outer ring in a direction away from the inner ring, and
Means for displacing the engagement surface of the inner ring in a direction away from the outer ring,
At least one of the overrunning clutches. Outer ring,
An inner ring,
An engagement member,
Spacing means
Equipped with
The engagement member is capable of engaging the inner ring and the outer ring,
The separating means can separate the engaging surface of the engaging member in the vertical direction from the engaging surface of at least one of the outer ring and the inner ring when the engaging member is engaged with the outer ring and the inner ring. And
The separating means is an overrunning clutch including a magnetostrictive element . Outer ring,
An inner ring,
An engagement member,
Spacing means
Equipped with
The engagement member is capable of engaging the inner ring and the outer ring,
The separating means can separate the engaging surface of the engaging member in the vertical direction from the engaging surface of at least one of the outer ring and the inner ring when the engaging member is engaged with the outer ring and the inner ring. And
The spacing means is configured to include a piezoelectric element,
A plurality of engaging members are provided,
Only one piezoelectric element is provided on the inner ring or outer ring,
The piezoelectric element is an overrunning clutch that can vibrate at the natural frequency of the inner ring or the outer ring to which the piezoelectric element is attached . The overrunning clutch according to claim 1 , wherein
The urging means is an overrunning clutch composed of an electromagnet . The overrunning clutch according to claim 1 , wherein
The biasing means is composed of an elastic member,
An electromagnet for urging the engaging member in the engaging direction,
The control means is an overrunning clutch that cuts off the power supply to the electromagnet during the first control .

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