Patent ID: 12259015

DESCRIPTION OF THE EMBODIMENTS

FIG.1toFIG.12illustrate a reverse-input blocking clutch1of an example of an embodiment of the present disclosure. Here, axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the reverse-input blocking clutch1, unless otherwise specified. In this example, the axial direction, radial direction, and circumferential direction of the reverse-input blocking clutch1coincide with the axial direction, radial direction, and circumferential direction of the input member3, and the axial direction, radial direction, and circumferential direction of the output member4. Further, one side in the axial direction refers to the input member3side (right side inFIG.1), and the other side in the axial direction refers to the output member4side (left side inFIG.1).

<Explanation of Structure of Reverse-Input Blocking Clutch>

The reverse-input blocking clutch1of this example includes a pressed member2, an input member3, an output member4, an engaging element5, and an elastic member6. The reverse-input blocking clutch1has a reverse input blocking function of transmitting rotational torque input to the input member3to the output member4, while completely blocking rotational torque reversely input to the output member4and not transmitting it to the input member3, or transmitting only a part of the rotational torque reversely input to the output member4to the input member3and blocking the remaining part.

In the reverse-input blocking clutch of the present disclosure, materials of the input member, the output member, the pressed member, and the engaging element are not particularly limited. For example, as these materials, in addition to metals such as iron alloys, copper alloys, and aluminum alloys, synthetic resins mixed with reinforcing fibers as necessary can be applied. Further, the input member, the output member, the pressed member, and the engaging element can be made of the same material, or can be made of different materials.

The pressed member2is supported and fixed to a fixed portion and does not rotate when the reverse-input blocking clutch1is used. Further, the pressed member2has a pressed surface7which is a cylindrical concave surface on an inner peripheral surface of an intermediate portion in the axial direction. In this example, the pressed member2includes an input-side housing element8and an output-side housing element9.

The output-side housing element9has a stepped cylindrical inner peripheral surface. The inner peripheral surface of the output-side housing element9has a small-diameter cylindrical surface portion10on the other side in the axial direction, a large-diameter cylindrical surface portion11on the one side in the axial direction, and a connecting surface portion12that connects the small-diameter cylindrical surface portion10and the large-diameter cylindrical surface portion11and faces the one side in the axial direction. In this example, the pressed surface7is configured by the large-diameter cylindrical surface portion11.

The output-side housing element9has an inward flange portion13protruding toward inside in the radial direction at an end portion on the other side in the axial direction of the small-diameter cylindrical surface portion10, and has a cylindrical inner diameter side fitting surface portion14on an outer peripheral surface of an end portion on the one side in the axial direction thereof.

The input-side housing element8includes a hollow circular plate-shaped side plate portion15, a large-diameter cylindrical portion16bent o over the entire circumference from an end portion on the outside in the radial direction of the side plate portion15toward the other side in the axial direction, and a small-diameter cylindrical portion17protruding from an intermediate portion in the radial direction of the side plate portion15toward the one side in the axial direction over the entire circumference. The large-diameter cylindrical portion16has an outer diameter side fitting surface portion18on an inner peripheral surface thereof.

In this example, by fitting the inner diameter side fitting surface portion14of the output-side housing element9and the outer diameter side fitting surface portion18of the input-side housing element8by spigot fitting without looseness, the input-side housing element8and the output-side housing element9are positioned in the radial direction. With the input-side housing element8and the output-side housing element9thus positioned in the radial direction, the input-side housing element8and the output-side housing element9are connected to each other by a connecting member such as a bolt (not illustrated) so as to configure the pressed member2. The pressed member2is supported and fixed to the fixed portion by screwing bolts inserted through holes provided in the fixed portion into screw holes19opening on a surface on the other side in the axial direction of the output-side housing element9.

The input member3is connected to an input-side mechanism such as an electric motor, and receives rotational toque. The input member3has an input shaft portion20, an input flange portion21, and an input-side engaging portion22.

In this example, the input shaft portion20has a cylindrical shape.

The input flange portion21protrudes toward outside in the radial direction over the entire circumference from the outer peripheral surface of an end portion on the other side in the axial direction of the input shaft portion20.

In this example, the input-side engaging portions22protrude toward the other side in the axial direction from two locations of a surface on the other side in the axial direction of the input flange portion21that are positioned on opposite sides in the radial direction. The number of the input-side engaging portion22corresponds to the number of the engaging element5. In this example, a pair of (two) input-side engaging portions22are provided, and the input-side engaging portions22are separated from each other in the radial direction of the input member3. The pair of input-side engaging portions22are arranged in portions of the surface on the other side in the axial direction of the input flange portion21that are deviated from the rotation center O of the input member3toward outside in the radial direction.

Each of the pair of input-side engaging portions22has an end surface shape that is substantially fan-shaped when viewed in the axial direction and that is symmetrical in the circumferential direction. Specifically, inner side surfaces23in the radial direction of the pair of input-side engaging portions22are configured by flat surfaces parallel to each other, and an outer side surface in the radial direction24of each of the input-side engaging portions22has the same cylindrical contour shape as the outer peripheral surface of the input flange portion21. Further, a pair of side surfaces25in the circumferential direction of each of the input-side engaging portions22are configured by flat surfaces that are inclined in directions away from each other as going toward outside in the radial direction.

The input member3is rotatably supported inside the input-side housing element8of the pressed member2by an input-side radial rolling bearing26. An outer ring27of the input-side radial rolling bearing26is fitted inside the small-diameter cylindrical portion17of the input-side housing element8without looseness, and is held in the axial direction between a portion on the inside in the radial direction of a side surface on the one side in the axial direction of the side plate portion15and a retaining ring30athat is locked in a portion on the one side in the axial direction of the small-diameter cylindrical portion17. An inner ring28of the input-side radial rolling bearing26is fitted around an end portion on the other side in the axial direction of the input shaft portion20of the input member3without looseness, and is held in the axial direction between a side surface on the one side in the axial direction of the input flange portion21and a retaining ring30bthat is locked on an outer peripheral surface of an intermediate portion in the axial direction of the input shaft portion20.

In this example, the input-side radial rolling bearing26is configured by a ball bearing using balls as rolling elements29. However, the input-side radial rolling bearing for supporting the input member3may be configured by a tapered roller bearing using tapered rollers or a roller bearing using cylindrical rollers as rolling elements.

The pair of input-side engaging portions22is arranged on the inside in the radial direction of the pressed surface7in a state where the input member3is rotatably supported inside the pressed member2.

The output member4is connected to an output-side mechanism such as a speed-reducing mechanism and outputs rotational torque. The output member4is coaxially arranged with the input member3. In this example, the output member4has an output shaft portion31, an output flange portion32, an output-side engaging portion33, and a small diameter shaft portion34.

The output shaft portion31has a columnar shape.

The output flange portion32protrudes toward outside in the radial direction over the entire circumference from an outer peripheral surface of an end portion on the one side in the axial direction of the output shaft portion31.

The output-side engaging portion33protrudes toward the one side in the axial direction from the central portion of a side surface on the one side in the axial direction of the output flange portion32. The output-side engaging portion33has a cam function. That is, the distance from the rotation center O of the output member4to the outer peripheral surface of the output-side engaging portion33is not constant in the circumferential direction.

The output-side engaging portion33has a substantially rectangular end surface shape when viewed from the axial direction. That is, the outer peripheral surface of the output-side engaging portion33is configured by a pair of long side portions38and a pair of short side portions39. The output-side engaging portion33is symmetrical with respect to a virtual plane which passes through the rotation center O of the output member4and is perpendicular to the pair of long side portions38, and is symmetrical with respect to a virtual plane which passes through the rotation center O of the output member4and is parallel to the pair of long side portions38. The pair of short side portions39exists on the same cylindrical surface as the outer peripheral surface of the output flange portion32.

The small diameter shaft portion34has a columnar shape and protrudes from the central portion of a side surface on the one side in the axial direction of the output flange portion32toward the one side in the axial direction. The axial length of the small diameter shaft portion34is larger than the axial length of the output-side engaging portion33. That is, a tip end portion (end portion on the one side in the axial direction) of the small diameter shaft portion34protrudes toward the one side in the axial direction from a tip end surface (end surface on the one side in the axial direction) of the output-side engaging portion33. Further, the outer-diameter dimension of the small diameter shaft portion34is larger than the distance between the pair of long side portions38of the output-side engaging portion33. That is, an outside portion in the radial direction of the small diameter shaft portion34protrudes from an intermediate portion in the lengthwise direction of the long side portions38toward outside in the radial direction.

The output shaft portion31of the output member4is rotatably supported inside the output-side housing element9by the output-side radial rolling bearing40. The outer ring41of the output-side radial rolling bearing40is fitted inside the small-diameter cylindrical surface portion10of the output-side housing element9without looseness, and is axially held between a side surface on the one side in the axial direction of the inward flange portion13and a retaining ring44alocked at an end portion on the one side in the axial direction of the small-diameter cylindrical surface portion10. An inner ring42of the output-side radial rolling bearing40is fitted around the output shaft portion31without looseness, and is axially held between a side surface on the other side in the axial direction of the output flange portion32and a retaining ring44blocked on an outer peripheral surface of an intermediate portion in the axial direction of the output shaft portion31.

In this example, the output-side radial rolling bearing40is configured by a ball bearing using balls as rolling elements43. However, the radial rolling bearing for supporting the output member4may be configured by a tapered roller bearing using tapered rollers or a roller bearing using cylindrical rollers as rolling elements.

The small diameter shaft portion34of the output member4is inserted inside the input member3. It is also possible to arrange a radial bearing such as a sliding bearing between an outer peripheral surface of the small diameter shaft portion34and an inner peripheral surface of the input member3. A locking groove59is formed over the entire circumference of the outer peripheral surface of an intermediate portion in the axial direction of the small diameter shaft portion34.

In a state where the output member4is rotatably supported inside the pressed member2, the output-side engaging portion33is arranged between the pair of input-side engaging portions22.

The engaging element5has a pressing surface45facing the pressed surface7, an input-side engaged portion50that can be engaged with the input-side engaging portion22, and an output-side engaged portion that can be engaged with the output-side engaging portion33, and is arranged between the pressed surface7and the output-side engaging portion33with regard to a first direction, which is a direction of moving toward or away from the pressed surface7, so as to move in the first direction.

In this example, a pair of (two) engaging elements5are provided. The pair of engaging elements5is arranged on the inside in the radial direction of the pressed member2so as to move in the first direction in a state where the respective pressing surfaces45are directed to opposite sides in the radial direction and the respective inner side surfaces in the radial direction face each other. In a case of implementing the reverse-input blocking clutch of the present disclosure, the number of engaging element is arbitrary, and the number of engaging element can be one or three or more. In this case, the configuration of the input-side engaging portion and the output-side engaging portion can be appropriately changed according to the number of engaging element.

In the description of the engaging element5, the radial direction of the engaging element5is the direction indicated by the arrow a inFIG.2, which is the direction of movement of the engaging elements5moving toward or away from the pressed surface7, that means the first direction. Further, the width direction of the engaging element5is a direction indicated by the arrow B inFIG.2, that means a direction perpendicular to the first direction.

Each engaging element5configuring the pair of engaging elements5has a pair of pressing surfaces45facing the pressed surface7at two locations separated in the circumferential direction of the outer side surface in the radial direction, and has a substantially arcuate notch46at the central portion in the circumferential direction located between the pair of pressing surfaces45on the outer side surface in the radial direction. Each pressing surface45is configured by a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface7.

When viewed from the axial direction, of the outer side surface in the radial direction of the engaging element5, portions deviated in the circumferential direction from the pair of pressing surfaces45including the notch46exist on the inside in the radial direction of a virtual circle centered on the center axis O of the input member3and in contact with the pair of pressing surfaces45. That is, in a state where the pair of pressing surfaces45is in contact with the pressed surface7, the portions of the outer side surface in the radial direction of the engaging element5that are deviated from the pair of pressing surfaces45in the circumferential direction do not come in contact with the pressed surface7.

It is preferable that each pressing surface45has a surface texture that has a larger coefficient of friction with respect to the pressed surface7than surfaces of other portions of the engaging element5. Further, the pressing surfaces45can be configured so as to be integral with the engaging elements5, or can be configured by surfaces made of friction materials fixed to, for example, the outer side surfaces in the radial direction of the engaging elements5by sticking, bonding, or the like.

Each of the engaging elements5includes a concave portion47having an arcuate cross-sectional shape at the central portion in the width direction of an end portion on the inside in the radial direction, and includes a pair of convex portions48protruding toward inside in the radial direction on both side portions of the concave portion47in the width direction. Further, the engaging element5includes a flat surface portion49extending in the width direction of the engaging element5when viewed from the axial direction, on the portion other than the concave portion47and the pair of convex portions48formed on the inner side surface in the radial direction thereof. The flat surface portions49of the pair of engaging elements5are configured by flat surfaces parallel to each other.

The inner surface of the concave portion47is configured by a cylindrical concave surface having a radius of curvature larger than the radius of curvature of the outer peripheral surface of the small diameter shaft portion34of the output member4. As illustrated inFIG.3, when rotational torque is input to the input member3, portions of the flat surface portion49located on both sides of the concave portion47in the width direction engage with the output-side engaging portion33. That is, in this example, the output-side engaged portion is configured by the portions of the flat surface portion49located on both sides of the concave portion47in the width direction.

The engaging element5has an input-side engaged portion50, which can be engaged with an input-side engaging portion22, at an intermediate portion in the radial direction of a central portion in the width direction. In this example, the input-side engaged portion50has a substantially arcuate opening shape when viewed from the axial direction, and is configured by a through hole axially penetrating through the intermediate portion in the radial direction of the engaging element5at the central location in the width direction. The input-side engaged portion50has a size that allows the input-side engaging portion22to be loosely inserted. Due to this, in a state where the input-side engaging portion22is inserted inside the input-side engaged portion50, gaps exist between the input-side engaging portion22and the inner surface of the input-side engaged portion50in the width direction and the radial direction of the engaging element5, respectively. As a result, the input-side engaging portion22can be displaced in the rotational direction of the input member3with respect to the input-side engaged portion50of the engaging element5, and the input-side engaged portion50can be displaced in the radial direction of the engaging element5with respect to the input-side engaging portion22. In this example, the input-side engaged portion50has a flat surface51parallel to the flat surface portion49on the inner side surface in the radial direction thereof (surface facing toward outside in the radial direction).

In a case of implementing the present disclosure, the input-side engaged portion can also be configured by a bottomed hole that opens only on a side surface on the one side in the axial direction of the engaging element. Alternatively, the input-side engaged portion can also be configured by a notch that opens on an outer side surface in the radial direction of the engaging element.

In a state where the pair of engaging elements5is arranged inside in the radial direction of the pressed member2, the pair of input-side engaging portions22of the input member3is arranged inside the input-side engaged portions50of the pair of engaging elements5, and the output-side engaging portion33of the output member4is arranged between the pair of flat surface portions49.

The inner diameter dimension of the pressed member2and the radial dimension of the engaging element5are regulated so that a gap exists at least one of portions between the pressed surface7and the pair of pressing surfaces45and between the tip end surfaces of the convex portions48of the pair of engaging elements5in a state where the pair of engaging elements5is arranged inside in the radial direction of the pressed member2.

In order to suppress looseness between the output-side engaging portion33of the output member4and the flat surface portions49configuring the output-side engaged portion of the engaging element5, the elastic member6elastically urges the engaging element5in a direction to bring the pair of pressing surfaces45closer to the pressed surface7with regard to the first direction.

In this example, an elastic member6is arranged in each engaging element5of the pair of engaging elements5. Specifically, the elastic member6is arranged between the output-side engaging portion33of the output member4and the flat surface portion49of the engaging element5. The number of the elastic member6can be changed according to the number of the engaging element5. That is, the pair of engaging elements5, a pair of (two) elastic members6, and the output-side engaging portion33are arranged such that the flat surface portions49and the pair of elastic members6hold the output-side engaging portion33from the outside in the radial direction.

In this example, the elastic member6is configured by a leaf spring. In a case of implementing the reverse-input blocking clutch of the present disclosure, the elastic member6can be configured by a coil spring, disc spring, or elastic material such as rubber, elastomer, or resin. As illustrated inFIG.6, the elastic member6has a pair of arm portions52and a pair of connecting portions53.

The pair of arm portions52has a substantially H-shaped planar shape when viewed from the plate thickness direction (radial direction of the engaging elements5). Specifically, each arm portion52has a pair of width direction plate pieces52ahaving a rectangular shape respectively, separated from each other in the axial direction, and extending in the width direction of the engaging elements5, and an axial direction plate piece52bconnecting the intermediate portions in the extending direction of the pair of width direction plate piece52a. That is, each arm portion52has a notch52cthat opens at a tip end portion (an end portion on the outside in the width direction of the engaging elements5).

Of the pair of connecting portions53, a connecting portion53on the one side in the axial direction connects base end portions of the width direction plate pieces52aon the one side in the axial direction of the pair of arm portions52(end portions thereof on the inside in the width direction of the engaging elements5), and a connecting portion53on the other side in the axial direction connects base end portions of the width direction plate pieces52aon the other side in the axial direction of the pair of arm portions52. In this example, each connecting portion53has a substantially U-shaped or substantially V-shaped end surface shape when viewed from the axial direction. However, in a case of implementing the present disclosure, the shape of the connecting portion is not particularly limited as long as it can prevent interference with the input member and the output member. For example, the connecting portion can be configured in a flat plate shape.

The pair of elastic members6engage the notches52cformed in the pair of arm portions52with the pair of convex portions48of the respective engaging elements5. In other words, the pair of convex portions48of the engaging element5is arranged inside the notches52cof the pair of arm portions52of the elastic member6. As a result, the elastic member6is supported so as not to displace in the axial and width directions, but so as to displace in the radial direction (first direction) with respect to the engaging element5. In this example, regardless of the positional relationship between each engaging element5and the output-side engaging portion33, specifically, regardless of the position in the radial direction of each engaging element5and the rotational phase of the output-side engaging portion33with respect to each engaging element5, the output-side engaging portion33is configured to elastically abut against the pair of elastic members6. As a result, looseness between the output-side engaging portion33and the output-side engaged portion is suppressed. Portions on both sides in the axial direction of the pair of arm portions52of each elastic member6protrude in the axial direction beyond both side surfaces in the axial direction of the engaging element5.

The reverse-input blocking clutch1of this example includes a pair of spacers54. Each spacer54of the pair of spacers54has a flat plate shape, has a substantially elliptical or substantially rectangular end surface shape when viewed from the axial direction, and has a through hole55through which the output-side engaging portion33and the small diameter shaft portion34can be inserted without looseness. The pair of spacers54is arranged on both sides in the axial direction of the pair of elastic members6in a state where the output-side engaging portion33and the small diameter shaft portion34are inserted into the through holes55without looseness.

The pair of spacers54prevents end surfaces of the pair of elastic members on both sides in the axial direction configured by fractured surfaces and sheared surfaces from coming into contact with a side surface on the other side in the axial direction of the input flange portion21of the input member3and a side surface on the one side in the axial direction of the output flange portion32of the output member4. Further, looseness of the engaging elements5is suppressed by holding the pair of elastic members6in the axial direction with the pair of spacers54and by extending the spacers54to positions facing the pair of arm portions52of the elastic members6and thus restricting looseness of the pair of arm portions52in the axial direction.

In this example, axial displacement of the engaging elements5is regulated since the pair of spacers54faces the pair of arm portions52of the elastic members6. However, it is also possible to regulate the axial displacement of the engaging elements by bringing the pair of spacers directly face the engaging elements.

As illustrated inFIG.9, of the pair of spacers54, at least a spacer54on the other side in the axial direction preferably has a chamfer section56on an opening edge on the other side in the axial direction of the through hole55. The chamfer section56is configured in a C-chamfered shape having a linear cross-sectional shape. Further, the chamfering depth of the chamfer section56is set to be equal to or larger than the chamfering radius of the corner R portion57that connects the side surface on the one side in the axial direction of the output flange portion32and the long side portion38of the output-side engaging portion33. The presence of the chamfer section56effectively prevents interference between the corner R portion57and the opening edge on the other side in the axial direction of the through hole55provided in the spacer54on the other side in the axial direction.

The reverse-input blocking clutch1of this example includes a stopper member58. The stopper member58is configured by a retaining ring having a partial cylindrical shape. That is, the stopper member58has a substantially C-shaped end surface shape when viewed from the axial direction. However, in a case of implementing the present disclosure, the stopper member can also be configured by a speed nut or a bush nut that has a hollow circular plate shape and has radial slits formed on an inside portion in the radial direction thereof.

The stopper member58is locked in a locking groove59provided on the outer peripheral surface of the intermediate portion in the axial direction of the small diameter shaft portion34, and faces the side surfaces on the one side in the axial direction of the pair of engaging elements5through a spacer54on the one side in the axial direction and the pair of elastic members6. In other words, the pair of elastic members6supported by the pair of engaging elements5so as not to relatively displace in the axial and width directions is held between the side surface on the one side in the axial direction of the output flange portion32and the stopper member58through the pair of spacers54. As a result, the pair of engaging elements5is prevented from displacing in the axial direction relative to the output member4. That is, the stopper member58configures a displacement prevention means.

However, in a case of implementing the reverse-input blocking clutch of the present disclosure, alternatively or additionally, the spacer can be locked to the output member and face the side surface in the axial direction of the engaging element directly or through the other member such as an elastic member. That is, the spacer can also be provided with a function as a stopper member.

Further, in this example, the stopper member58faces the side surface of the engaging element5on the one side in the axial direction through a spacer54and the elastic member6. However, the spacer54can be omitted or can directly face the side surface of the engaging element5on the one side in the axial direction. Alternatively, a displacement prevention means for preventing displacement of the engaging element in the axial direction relative to the output member can also be configured by, for example, a crimpled portion formed on the output member.

<Explanation of Operation of Reverse-Input Blocking Clutch>

The operation of the reverse-input blocking clutch1of this example will be descried with reference toFIG.3andFIG.4. Note that inFIG.3andFIG.4, gaps between the input member3and the output member4and the pair of engaging elements5are exaggerated.

First, a case where rotational torque is input to the input member3from the input-side mechanism will be described.

When rotational torque is input to the input member3, as illustrated inFIG.3, the input-side engaging portion22rotates in the rotational direction of the input member3(counterclockwise direction in the example illustrated inFIG.4) inside the input-side engaged portion50. Then, the inner side surface23in the radial direction of the input-side engaging portion22presses the flat surface51of the input-side engaged portion50toward inside in the radial direction, thereby moving the engaging element5in a direction away from the pressed surface7. That is, the engaging element5is moved toward inside in the radial direction based on engagement with the input member3. In this example, due to the engagement between the pair of input-side engaging portions22and the pair of engaging elements5, the engaging element5located on the upper side inFIG.3is moved toward the lower side and the engaging element5located on the lower side inFIG.3is moved toward the upper side.

As a result, the engaging element5moves inward in the radial direction, and the flat surface portion49of the output-side engaged portion of the engaging element5engages with the output-side engaging portion33of the output member4. In this example, the inner side surfaces in the radial direction of the pair of engaging elements5move in a direction toward each other, and the flat surface portions49of the pair of engaging elements5hold the output-side engaging portion33of the output member4from both sides in the radial direction. Specifically, when the flat surface portion49of the engaging element5and the output-side engaging portion33engage, the output member4rotates so that the long side portion38of the output-side engaging portion33are parallel to the flat surface portion49of the engaging element5, and the output-side engaging portion33and the flat surface portion49are brought into contact without looseness. As a result, rotational torque input to the input member3is transmitted to the output member4through the engaging element5and output from the output member4.

In the reverse-input blocking clutch1of this example, when rotational torque is input to the input member3, the engaging element5moves in the direction away from the pressed surface7regardless of the rotational direction of the input member3. Then, the rotational torque input to the input member3is transmitted to the output member4through the engaging element5.

Next, a case where rotational torque is reversely input to the output member4from an output-side mechanism will be described.

When rotational torque is reversely input to the output member4, as illustrated inFIG.4, the output-side engaging portion33rotates in the rotational direction of the output member4(clockwise direction in the example illustrated inFIG.4). Then, of the outer peripheral surface of the output-side engaging portion33, a connecting portion (corner portion) between the long side portion38and the short side portion39presses the flat surface portion49of the output-side engaged portion of the engaging element5toward outside in the radial direction, and the engaging element5moves in the direction closer to the pressed surface7, that is, toward outside in the radial direction. As a result, the pressing surface45of the engaging element5is frictionally engaged with the pressed surface7. In this example, by engaging the output-side engaging portion33of the output member4and the flat surface portions49of the pair of engaging elements5, the pair of engaging elements5moves in a direction away from each other, that is, the engaging element5located on the upper side inFIG.4is moved toward the upper side and the engaging element5located on the lower side inFIG.4is moved toward the lower side respectively such that the pressing surfaces45of the pair of engaging elements5are frictionally engaged with the pressed surface7.

As a result, the rotational torque reversely input to the output member4is completely blocked and not transmitted to the input member3, or only a part of the rotational torque reversely input to the output member4is transmitted to the input member3and the remaining part is blocked. In order to completely block the rotational torque reversely input to the output member4and prevent it from being transmitted to the input member3, the output member4is locked by holding the engaging element5between the output-side engaging portion33and the pressed member2so as to prevent the pressing surface45of the engaging element5from sliding (rotating) with respect to the pressed surface7. On the other hand, in order to transmit only a part of the rotational torque reversely input to the output member4to the input member3and block the remaining part, the output member4is semi-locked by holding the engaging element5between the output-side engaging portion33and the pressed member2so as to allow the pressing surface45to slide with respect to the pressed surface7.

In the reverse-input blocking clutch1of this example, the size of the gaps between each component member is adjusted so as to enable the operation described above. In particular, in the positional relationship in which the pressing surface45of the engaging element5is in contact with the pressed surface7, gaps are provided between the inner side surface23in the radial direction of the input-side engaging portions22and the inner surface of the input-side engaged portion50so as to allow the pressing surface45to be further pressed against the pressed surface7based on pressing the corner portion of the output-side engaging portion33presses the flat surface portion49. As a result, the input-side engaging portion22is prevented from blocking the engaging element5moving toward outside in the radial direction when rotational torque is reversely input to the output member4. Further, even after the pressing surface45contacts the pressed surface7, the output member4is properly locked or semi-locked by making the surface pressure acting on a contact portion between the pressing surface45and the pressed surface7change depending on the magnitude of the rotational torque reversely input to the output member4.

<How to Assemble Reverse-Input Blocking Clutch>

The reverse-input blocking clutch1of this example can be assembled, for example, as follows.

First, the output-side engaging portion33of the output member4and the small diameter shaft portion34are inserted into the through holes55of the pair of spacers54. The elastic member6is supported on the engaging element5by engaging the notches52cof the elastic member6with the pair of convex portions48of the engaging element5. Next, the pair of engaging elements5is arranged so that the flat surface portions49and the pair of elastic members6hold the output-side engaging portion33of the output member4from outside in the radial direction. Then, the stopper member58is locked in the locking groove59of the output member4. By doing this, a preliminary assembly60as illustrated inFIG.7andFIG.8is obtained.

The inner ring42of the output-side radial rolling bearing40is fitted around the output shaft portion31of the output member4without looseness, and the retaining ring44bis locked on the outer peripheral surface of the intermediate portion in the axial direction of the output shaft portion31.

The output member4is inserted inside the output-side housing element9from the one side in the axial direction. When inserting the output member4inside the output-side housing element9, an assembly jig (not illustrated) is used to displace the pair of engaging elements5in a direction toward each other (toward inside in the radial direction) against the elasticity of the pair of elastic members6. After the end surface on the other side in the axial direction of the outer ring41of the output-side radial rolling bearing40comes into contact with the side surface on the one side in the axial direction of the inward flange portion13, the assembly jig is retracted, and the pair of engaging elements5is displaced in a direction away from each other (toward outside in the radial direction) by the elasticity of the pair of elastic members6, and the pressing surfaces45are brought into contact with the pressed surface7. Then, a retaining ring44ais engaged with an end portion on the one side in the axial direction of the small-diameter cylindrical surface portion10to obtain an output-side assembly61as illustrated inFIG.11.

The steps for assembling the output-side assembly61can be suitably rearranged or performed simultaneously as long as no contradiction occurs.

Further, an input-side assembly62as illustrated inFIG.12is obtained by rotatably supporting the input member3inside the input-side housing element8by the input-side radial rolling bearing26.

Next, in a state where the phases of the pair of input-side engaging portions22of the input member3and the input-side engaged portions50of the pair of engaging elements5in the circumferential direction coincide, the output-side assembly61and the input-side assembly62are displaced toward each other in the axial direction. As a result, the inner diameter side fitting surface portion14of the output-side housing element9and the outer diameter side fitting surface portion18of the input-side housing element8are fitted together without looseness, and the pair of input-side engaging portions22are inserted into the input-side engaged portions50. Then, the reverse-input blocking clutch1is assembled by coupling the input-side housing element8and the output-side housing element9to each other using coupling members.

In the reverse-input blocking clutch1of this example, the stopper member58prevents the pair of engaging elements5from being relatively displaced in the axial direction with respect to the output member4. Therefore, as illustrated inFIG.11, the output member4, the pair of engaging elements5, and the output-side housing element9can be formed into a subassembly as the output-side assembly61. By displacing the output-side assembly61and the input-side assembly62in a direction toward each other in the axial direction, the inner diameter side fitting surface portion14and the outer diameter side fitting surface portion18are fitted together without looseness, and the pair of input-side engaging portions22of the input member3is inserted into the input-side engaged portions50of the pair of engaging elements5to combine the output-side assembly61and the input-side assembly62.

Comparative Example

FIG.13toFIG.15illustrate a reverse-input blocking clutch of a comparative example in relation to the present disclosure. The reverse-input blocking clutch100of the comparative example does not include the pair of spacers54, the stopper member58, and a structure for attaching these to the reverse-input blocking clutch100, however, other than that, its basic construction is similar to the reverse-input blocking clutch1of an example of an embodiment of the present disclosure.

When assembling the reverse-input blocking clutch100, as illustrated inFIG.14andFIG.15, a pair of input-side engaging portions104of the input member103is inserted into input-side engaged portions102of a pair of engaging elements101, and a leaf spring105configuring an elastic member is arranged on the inside in the radial direction of each engaging element101. Further, an input shaft portion106of the input member103is rotatably supported by an input-side radial rolling bearing107with respect to an input-side housing element109configuring a pressed member108. In this way, an input-side assembly comprising a pair of engaging elements101, an input member103, a pair of leaf springs105, an input-side radial rolling bearing107, and an input-side housing element109is obtained.

Further, an output shaft portion111of an output member110is rotatably supported inside an output-side housing element113configuring a pressed member108by an output-side radial rolling bearing112. In this way, the output member110, the output-side radial rolling bearing112, and the output-side housing element113are combined to obtain an output-side assembly.

Next, the input-side assembly and the output-side assembly are brought close to each other in the axial direction to insert an output-side engaging portion114of the output member110between a pair of leaf springs105arranged on the inside in the radial direction of the pair of engaging elements101. At the same time, the pair of engaging elements101is arranged inside the pressed surface115provided on an inner peripheral surface of the output-side housing element113so as to bring pressing surfaces116provided on the outer side surfaces in the radial direction of the pair of engaging elements101face the pressed surface115. Then, the pressed member108is configured by coupling and fixing the input-side housing element109and the output-side housing element113, thereby obtaining the reverse-input blocking clutch100.

When inserting the output-side engaging portion114between the pair of leaf springs105, the pair of leaf springs105and the output-side engaging portion114cannot be visually confirmed from the outside. Due to this, the work of inserting the output-side engaging portion114between the pair of leaf springs105becomes troublesome, and the assembly cost may increase.

Further, although the pair of leaf springs105is elastically held between the output-side engaged portions117and the output-side engaging portion114, each leaf spring105is not supported by any member so as not to be able to fall out. Therefore, in a state before inserting the output-side engaging portion114between the pair of leaf springs105, these leaf springs105move in a direction toward each other, and the distance between the pair of leaf springs105may be narrowed. From this point of view as well, the work of inserting the output-side engaging portion114of the output member110between the pair of leaf springs105may become troublesome.

On the other hand, in the reverse-input blocking clutch1of an example of an embodiment of the present disclosure, when displacing the output-side assembly61and the input-side assembly62in a direction toward each other in the axial direction, the pair of input-side engaging portions22can be loosely inserted into the input-side engaged portions50as long as the phases in the circumferential direction of the pair of input-side engaging portions22and the input-side engaged portions50of the pair of engaging elements5coincide. That is, with the reverse-input blocking clutch1of this example, it is not necessary to insert the output-side engaging portion114between the pair of leaf springs105while increasing the distance between the pair of leaf springs105as in the method of assembling the reverse-input blocking clutch100of the comparative example. Therefore, with the reverse-input blocking clutch1of this example, assembly work can be facilitated and assembly efficiency can be improved.

In the reverse-input blocking clutch100of the comparative example, the pair of engaging elements101can be displaced in the axial direction by several millimeters with respect to the input member103and the output member110. Due to this, there is a possibility that the engaging elements101incline in the axial direction. When the engaging elements101move toward outside in the radial direction while the engaging elements101inclined in the axial direction, the pressing surfaces116and the pressed surface115are locally brought into contact and bite occurs. This may result in an increase in the force required to switch from the locked or semi-locked state to the unlocked or semi-unlocked state, and plastic deformation may occur in the pressing surfaces116and/or the pressed surface115.

On the other hand, in the reverse-input blocking clutch1of this example, the pair of engaging elements5is prevented from being inclined in the axial direction by preventing relative displacement of the pair of engaging elements5in the axial direction with respect to the output member4by the stopper member58. As a result, switching operation of the output member4between the locked and semi-locked state or unlocked and semi-unlocked state can be performed stably.

REFERENCE SIGNS LIST

1Reverse-input blocking clutch2Pressed member3Input member4Output member5Engaging element6Elastic member7Pressed surface8Input-side housing element9Output-side housing element10Small-diameter cylindrical surface portion11Large-diameter cylindrical surface portion12Connecting surface portion13Inward flange portion14Inner diameter side fitting surface portion15Side plate portion16Large-diameter cylindrical portion17Small-diameter cylindrical portion18Outer diameter side fitting surface portion19Screw hole20Input shaft portion21Input flange portion22Input-side engaging portion23Inner side surface in the radial direction24Outer side surface in the radial direction25Side surface in the circumferential direction26Input-side radial rolling bearing27Outer ring28Inner ring29Rolling elements30a,30bRetaining ring31Output shaft portion32Output flange portion33Output-side engaging portion34Small diameter shaft portion38Long side portion39Short side portion40Output-side radial rolling bearing41Outer ring42Inner ring43Rolling element44a,44bRetaining ring45Pressing surface46Notch47Concave portion48Convex portion49Flat surface portion50Input-side engaged portion51Flat surface52Arm portion52aWidth direction plate piece52bAxial direction plate piece52cNotch53Connecting portion54Spacer55Through hole56Chamfer section57Corner R portion58Stopper member59Locking groove60Preliminary assembly61Output-side assembly62Input-side assembly100Reverse-input blocking clutch101Engaging element102Input-side engaged portion103Input member104Input-side engaging portion105Leaf spring106Input shaft portion107Input-side radial rolling bearing108Pressed member109Input-side housing element110Output member111Output shaft portion112Output-side radial rolling bearing113Output-side housing element114Output-side engaging portion115Pressed surface116Pressing surface117Output-side engaged portion