Reverse input cutoff clutch, torque transmission device, and method for adjusting tension of same

Abstract

The present invention achieves a reverse input cutoff clutch structure that makes it possible to temporarily disable a reverse input cutoff function. A pressed member 2 comprises: a main body section 7 having a pressed surface 6 on an inner peripheral surface thereof; and a side plate section 8 extending radially inward from an axial end section of the main body section 7. The side plate section 8 has an observation hole 10 axially penetrating a part including a part of which the radial position coincides with a part deviating from a pressing surface 31 in the circumferential direction in a radially outward surface of an engagement element 5.

Description

Reverse input blocking clutch, and torque transmission device and tension adjustment method thereof.

[0001] This disclosure relates to a reverse input blocking clutch that transmits rotational torque input to an input member to an output member, while completely blocking rotational torque input in reverse to an output member and not transmitting it to the input member, or transmitting only a portion of it to the input member and blocking the remainder, as well as a torque transmission device equipped with the reverse input blocking clutch, and a method for adjusting the tension thereof.

[0002] Japanese Patent Publication No. 2012-135936 describes a belt-type torque transmission device as a type of torque transmission device that transmits torque between a pair of rotating members arranged in parallel. The torque transmission device described in Japanese Patent Publication No. 2012-135936 comprises a drive pulley that is rotationally driven by a motor or the like, a driven pulley arranged parallel to the drive pulley, an endless belt stretched between the drive pulley and the driven pulley, and a tension pulley that is pressed against the endless belt and applies tension to the endless belt.

[0003] International Publication No. 2023 / 136149 describes a reverse input blocking clutch that transmits rotational torque input to an input member connected to an input-side mechanism such as a drive source to an output member connected to an output-side mechanism such as a reduction mechanism, while completely blocking rotational torque input in reverse to the output member and not transmitting it to the input member, or transmitting only a portion of it to the input member and blocking the rest. The reverse input blocking clutch described in International Publication No. 2023 / 136149 includes a mechanism to prevent the rotation of the output member when rotational torque is input in reverse to the output member.

[0004] Specifically, in the locking reverse-input blocking clutch described in International Publication No. 2023 / 136149 pamphlet, when rotational torque is input to the input member, based on the engagement of the input-side engaging portion of the input member with the input-side engaged portion of the engaging element, the engaging element moves in a direction away from the pressed surface provided on the pressed member, and by engaging the output-side engaged portion of the engaging element with the output-side engaging portion of the output member, the rotational torque input to the input member is transmitted to the output member. On the other hand, when rotational torque is reverse-input to the output member, based on the engagement of the output-side engaging portion of the output member with the output-side engaged portion of the engaging element, the engaging element moves in a direction approaching the pressed surface, presses the pressing surface against the pressed surface, and frictionally engages the pressing surface with the pressed surface.

[0005] JP-A-2012-135936 International Publication No. 2023 / 136149 pamphlet

[0006] In a mechanical device provided with a belt-type torque transmission device, depending on the type of the mechanical device, in order to hold the position or posture of the driven part regardless of the force acting on the driven part connected to the driven pulley, even when no operation is performed to change the position or posture of the driven part, it is necessary to energize the motor to exert a rotational force, which is disadvantageous in terms of energy saving.

[0007] If the reverse-input blocking clutch described in International Publication No. 2023 / 136149 pamphlet is incorporated between the output shaft of the motor and the drive pulley, when the driven part attempts to change its position or posture and the output member rotates even slightly in a state where no rotational torque is input to the input member, the reverse-input blocking function of the reverse-input blocking clutch operates. For this reason, in a belt-type torque transmission device, it becomes possible to hold the position or posture of the driven part without energizing the motor.

[0008] However, with such a structure, even if the torque transmission device equipped with a reverse input blocking clutch is incorporated into the machine and the pressure applied by the tension pulley to the endless belt is adjusted to adjust the tension of the endless belt, the drive pulley will not rotate at all due to the reverse input blocking function of the reverse input blocking clutch, which may cause problems in properly adjusting the tension of the endless belt. In this case, in order to properly adjust the tension of the endless belt, it is necessary to temporarily disable the reverse input blocking function of the reverse input blocking clutch.

[0009] This disclosure aims to provide a reverse input blocking clutch that can temporarily disable a reverse input blocking function that either prevents the transmission of rotational torque reversed into an output member to an input member, or transmits only a portion of it to the input member and blocks the rest, as well as a torque transmission device equipped with the reverse input blocking clutch and a method for adjusting its tension.

[0010] A reverse input blocking clutch according to one aspect of the present disclosure comprises a pressed member, an input member, an output member, and an engaging element.

[0011] The member to be pressed has a surface to be pressed on its inner circumferential surface.

[0012] The input member has an input-side engaging portion located radially inward of the pressed surface, is connected to an input-side mechanism on one axial side, and is arranged coaxially with the pressed surface.

[0013] The output member has an output-side engaging portion that is positioned radially inward from the input-side engaging portion, is connected to the output-side mechanism on the other axial side, and is positioned coaxially with the pressed surface.

[0014] The engaging element has a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and is arranged to allow the pressing surface to move in the near-far direction relative to the pressed surface.

[0015] When rotational torque is input to the input member, the engaging element moves radially away from the pressed surface based on the input-side engaging portion engaging with the input-side engaged portion, thereby engaging the output-side engaged portion with the output-side engaging portion and transmitting the rotational torque input to the input member to the output member. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, causing the pressing surface to frictionally engage with the pressed surface.

[0016] The pressed member comprises a main body portion having the pressed surface on its inner circumferential surface, and a side plate portion extending radially inward from the axial end of the main body portion.

[0017] In particular, in a reverse input blocking clutch according to one aspect of the present disclosure, the side plate portion has an observation hole that penetrates axially through a portion of the radial outer surface of the engaging element facing the pressed surface, including a portion whose radial position coincides with a portion that is circumferentially offset from the pressing surface.

[0018] In a reverse input blocking clutch according to one aspect of the present disclosure, the number of observation holes may be an integer multiple of the number of engaging elements.

[0019] In a reverse input blocking clutch according to one aspect of the present disclosure, the engaging element may be composed of two engaging elements. In this case, the circumferential position of the portion of the radial outer surface of one of the two engaging elements that is away from the pressing surface coincides with one of the observation holes, and the circumferential position of the portion of the radial outer surface of the other engaging element that is away from the pressing surface coincides with the other observation hole.

[0020] In a reverse input blocking clutch according to one aspect of the present disclosure, the pressing surface can be composed of two pressing surfaces provided at two positions on the radial outer surface of the engaging element that are spaced apart from each other in the circumferential direction, and the engaging element can have a non-contact surface on the radial outer surface between the two pressing surfaces in the circumferential direction that does not contact the pressed surface when the two pressing surfaces are in contact with the pressed surface.

[0021] In this case, the non-contact surface can be composed of a flat surface perpendicular to the radial direction of the engaging element.

[0022] In a reverse input blocking clutch according to one aspect of the present disclosure, the side plate portion can extend radially inward from the other axial end of the main body portion.

[0023] In this case, the output member can be rotatably supported on the inner circumferential surface of the side plate portion by radial rolling bearings.

[0024] Additionally or alternatively, the output member may have a marker that allows confirmation of the phase in the rotational direction of the output member.

[0025] A torque transmission device according to one aspect of the present disclosure comprises: a torque input unit rotationally driven by a drive source; a drive member arranged coaxially with the torque input unit; a driven member arranged parallel to the drive member; a flexible annular transmission member spanning between the drive member and the driven member; an adjustment member pressed against the transmission member to apply tension to the transmission member; and a reverse input blocking clutch arranged between the torque input unit and the drive member.

[0026] In particular, in a torque transmission device according to one aspect of the present disclosure, the reverse input interruption clutch is configured with the reverse input interruption clutch according to one aspect of the present disclosure.

[0027] The input member is either composed of the torque input section, or is composed as a separate component from the torque input section and is fixed coaxially with respect to the torque input section.

[0028] The output member is configured integrally with the drive member, or is configured as a separate member from the drive member, and is fixed coaxially with respect to the drive member.

[0029] A method for adjusting the tension of a torque transmission device according to one aspect of the present disclosure is a method for adjusting the tension of a transmission member of a torque transmission device according to one aspect of the present disclosure, wherein a tool is inserted radially inward through the observation hole into the main body, and the engaging element is moved radially inward with the tool, thereby separating the pressing surface from the pressed surface, and the tension of the transmission member is adjusted by adjusting the pressing force of the adjustment member against the transmission member.

[0030] According to a reverse input blocking clutch in one aspect of the present disclosure, it is possible to temporarily disable the reverse input blocking function that either does not transmit the rotational torque reversed into the output member to the input member, or transmits only a portion of it to the input member and blocks the rest.

[0031] Figure 1 is a perspective view of a reverse input blocking clutch of a first example embodiment of the present disclosure. Figure 2 is an end view of the reverse input blocking clutch of the first example, viewed from the output member side. Figure 3 is an end view of the reverse input blocking clutch of the first example, viewed from the input member side. Figure 4 is a cross-sectional view taken along line I-I of Figure 2. Figure 5 is a cross-sectional view taken along line II-II of Figure 4. Figure 6 is a cross-sectional view taken along line II-II of Figure 4, showing the state in which rotational torque is input to the input member, with the biasing member omitted. Figure 7 is a cross-sectional view taken along line II-II of Figure 4, showing the state in which rotational torque is input to the output member, with the biasing member omitted. Figure 8 is a schematic diagram illustrating a method for disabling the reverse input blocking function of the reverse input blocking clutch of the first example. Figure 9 is an end view showing a torque transmission device incorporating the reverse input blocking clutch of the first example. Figure 10 is a schematic diagram showing a torque transmission device incorporating the reverse input blocking clutch of the first example. Figure 11 is an end view of Figure 10, viewed from the left side. Figure 12 is a diagram corresponding to Figure 2, showing a reverse input interruption clutch of a second embodiment of the present disclosure. Figure 13 is a cross-sectional view taken along line III-III of Figure 12.

[0032] [First Example] A first example of an embodiment of the present disclosure will be described with reference to Figures 1 to 11.

[0033] In the following description, unless otherwise specified, the axial, radial, and circumferential directions refer to the axial, radial, and circumferential directions of the pressed surface 6. The axial, radial, and circumferential directions of the pressed surface 6 coincide with the axial, radial, and circumferential directions of the input member 3, and also coincide with the axial, radial, and circumferential directions of the output member 4. Furthermore, one axial side refers to the input side of the reverse input blocking clutch 1 (the right side in Figures 4 and 8), and the other axial side refers to the output side of the reverse input blocking clutch 1 (the left side in Figures 4 and 8).

[0034] <Explanation of the structure of the reverse input blocking clutch> The reverse input blocking clutch 1 of this disclosure comprises a pressed member 2, an input member 3, an output member 4, and an engaging element 5.

[0035] Of the elements constituting the reverse input blocking clutch 1, the pressed member 2, the input member 3, and the output member 4 have the same configuration and function as a conventional reverse input blocking clutch.

[0036] The pressed member 2 has a pressed surface 6 on its inner circumferential surface. The input member 3 has an input-side engaging portion 14 located radially inward of the pressed surface 6 and is arranged coaxially with the pressed surface 6. The output member 4 has an output-side engaging portion 19 located radially inward of the input-side engaging portion 14 and is arranged coaxially with the pressed surface 6. The engaging element 5 has a pressing surface 31 facing the pressed surface 6, an input-side engaged portion 32 that can engage with the input-side engaging portion 14, and an output-side engaged portion 33 that can engage with the output-side engaging portion 19, and is arranged to be movable in the radial direction.

[0037] When rotational torque is input to the input member 3, the engaging element 5 moves radially away from the pressed surface 6 based on the input-side engaging portion 14 engaging with the input-side engaged portion 32, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output-side engaged portion 33 with the output-side engaging portion 19.

[0038] In response to this, when rotational torque is input in reverse to the output member 4, the engaging element 5, based on the fact that the output-side engaging portion 19 engages with the output-side engaged portion 33, presses its pressing surface 31 against the pressed surface 6, causing the pressing surface 31 to frictionally engage with the pressed surface 6. In other words, the reverse input blocking clutch 1 either completely blocks the rotational torque that is input in reverse to the output member 4 and does not transmit it to the input member 3, or transmits only a portion of it to the input member 3 and blocks the rest.

[0039] In this specification, the direction of the pressing surface 31 of the engaging element 5 relative to the pressed surface 6 is defined as the first direction (up and down direction in Figures 5 to 7), and the direction perpendicular to both the axial direction of the pressed surface 6 and the first direction is defined as the second direction (left and right direction in Figures 5 to 7). With respect to the engaging element 5, the direction coinciding with the first direction is defined as the radial direction of the engaging element 5 (direction indicated by arrow α in Figure 5), and the direction coinciding with the second direction is defined as the width direction of the engaging element 5 (direction indicated by arrow β in Figure 5).

[0040] The input-side engaging portion 14 of the input member 3 and the output-side engaging portion 19 of the output member 4 are positioned radially inward of the pressed surface 6. With respect to the first direction, the input-side engaging portion 14, the input-side engaged portion 32, the output-side engaged portion 33, and the output-side engaging portion 19 are arranged in that order radially inward of the pressed surface 6. Furthermore, the input-side engaging portion 14, the output-side engaging portion 19, and the engaging element 5 are rotatable radially inward of the pressed surface 6.

[0041] In particular, the reverse input blocking clutch 1 of this disclosure is characterized by an improved configuration of the pressed member 2, which allows the reverse input blocking function, which either does not transmit the rotational torque reversed into the output member 4 to the input member 3, or transmits a portion of it to the input member 3 and blocks the rest, to be temporarily disabled. The components of the reverse input blocking clutch 1 will be described below, focusing on the pressed member 2 and this characteristic.

[0042] [Pressed Member] The pressed member 2 has a pressed surface 6 on its inner peripheral surface. The pressed surface 6 constitutes a surface that contacts the pressing surface 31 of the engaging member 5 when the engaging member 5 moves radially outward in a direction approaching the pressed surface 6 with respect to the first direction. That is, the pressed surface 6 has a function of frictionally engaging with the pressing surface 31 of the engaging member 5 when rotational torque is reversely input to the output member 4.

[0043] The pressed member 2 is supported by a fixed portion that does not rotate even when the reverse input blocking clutch 1 is in use, or is provided integrally with the fixed portion so that its rotation is restricted.

[0044] In the reverse input blocking clutch 1 of the present disclosure, the pressed member 2 includes a main body portion 7 and a side plate portion 8.

[0045] The main body portion 7 has a pressed surface 6 on a portion of its inner peripheral surface where the engaging member 5 is disposed inside. Therefore, the inner peripheral surface of the main body portion 7 constitutes the inner peripheral surface of the pressed member 2. The pressed surface 6 is circular in shape when viewed from the axial direction, and although not limited thereto, in this example, it is in the shape of a cylindrical surface with no change in inner diameter in the axial direction.

[0046] In this example, the main body portion 7 has a substantially cylindrical shape and has a convex portion 9 protruding radially outward at one position in the circumferential direction of the outer peripheral surface. In this example, by engaging the convex portion 9 with a key groove provided in the fixed portion, the rotation of the pressed member 2 with respect to the fixed portion is restricted.

[0047] The side plate portion 8 extends radially inward from an axial end portion of the main body portion 7. Specifically, the side plate portion 8 extends radially inward from an end portion on one side in the axial direction or an end portion on the other side in the axial direction of the main body portion 7. In this example, the side plate portion 8 extends radially inward from the end portion on the other side in the axial direction of the main body portion 7 and has a substantially hollow circular plate shape.

[0048] The side plate portion 8 has an observation hole 10 that axially penetrates a portion including a portion whose radial position coincides with a portion of the outer radial surface of the engaging member 5 that is circumferentially deviated from the pressing surface 31 among the portions facing the pressed surface 6.

[0049] The observation hole 10 is an element for inserting a tool 51 radially inward into the main body 7 when temporarily disabling the reverse input blocking function. By inserting the tool 51 radially inward into the main body 7 through the observation hole 10, the engaging element 5 is moved radially inward, and the pressing surface 31 is separated from the pressed surface 6, thereby temporarily disabling the reverse input blocking function.

[0050] The radial position of the observation hole 10 is restricted to a position where the engaging element 5 can be moved radially inward by a tool 51 inserted radially into the main body 7 through the observation hole 10, in order to temporarily disable the reverse input blocking function. Specifically, the radial position of the observation hole 10 is restricted to a position where the tool 51 can be inserted between the portion of the radial outer surface of the engaging element 5 that is circumferentially off from the pressing surface 31 and the surface to be pressed 6, with the pressing surface 31 in contact with the pressed surface 6. In this example, the radial position of the observation hole 10 is restricted so that the radial outer surface of the inner surface of the observation hole 10 is located on the same cylindrical surface as the surface to be pressed 6.

[0051] The shape of the observation hole 10 is not limited, as long as it temporarily disables the reverse input blocking function and allows the output member 4 to be rotated slightly while the reverse input blocking function is disabled. For example, the observation hole 10 can have a circular, oval, elliptical, rectangular, sector-shaped, or partially annular shape, or a similar opening shape when viewed from the axial direction. In this example, the observation hole 10 has a substantially partially annular opening shape centered on the central axis of the pressed surface 6.

[0052] The circumferential length of the observation hole 10 is determined according to the number of engaging elements 5, the type and structure of the mechanical device into which the reverse input blocking clutch 1 is incorporated, and the rotational tolerance of the output member 4.

[0053] Specifically, the circumferential length of the observation hole 10 is appropriately determined according to the structure of the torque transmission device 52, the type of torque transmission device 52, the rotational tolerance required of the output member 4 when the reverse input blocking function is temporarily disabled, the arrangement of the side plate portion 8 where the observation hole 10 is located, and the arrangement relationship between the side plate portion 8 and other elements constituting the torque transmission device 52.

[0054] For example, as in this example, if the reverse input blocking clutch 1 is incorporated into the torque transmission device 52 and it is necessary to temporarily disable the reverse input blocking function in order to adjust the tension of the transmission member 56, then it is necessary to allow a slight rotation of the output member 4 while the reverse input blocking function is disabled. More specifically, if the observation hole 10 is substantially partially annular and the ends on both sides in the circumferential direction are semicircular, the circumferential length of the shortest part of the observation hole 10 can be in the range of 15 degrees to 30 degrees, although this is not limited to the central angle with respect to the central axis of the pressed surface 6.

[0055] The number of observation holes 10 is preferably determined according to the number of engaging elements 5. When the engaging element 5 is composed of multiple engaging elements 5, it is preferable to provide the same number or more observation holes 10. In this case, the circumferential positions of the multiple observation holes 10 are restricted so that the tool 51 can simultaneously move the multiple engaging elements 5 radially inward, thereby separating each of the pressing surfaces 31 from the pressed surface 6.

[0056] It is not prohibited for the number of observation holes 10 to be greater than the number of engaging elements 5. In this case, it is preferable that the number of observation holes 10 be an integer multiple of the number of engaging elements 5. The number of observation holes 10 can be determined according to the structure of the device to which the reverse input blocking clutch 1 is applied and the arrangement of other elements constituting the device, but in any case, it is preferable that the number of observation holes 10 be the same as the number of two or more engaging elements 5, or an integer multiple of the number of engaging elements 5.

[0057] When the engaging element 5 is composed of two engaging elements 5, the number of observation holes 10 is a multiple of 2. In this case, the circumferential position of the portion of the radial outer surface of one of the two engaging elements 5 that is not adjacent to the pressing surface 31 coincides with one of the observation holes 10, and the circumferential position of the portion of the radial outer surface of the other engaging element 5 that is not adjacent to the pressing surface 31 coincides with another observation hole 10.

[0058] In this example, the engaging element 5 is composed of two engaging elements 5. The observation holes 10 are composed of two observation holes 10, corresponding to the number of engaging elements 5. The circumferential position of the portion of the radial outer surface of one of the two engaging elements 5 (for example, the upper right side in Figure 3) that is not adjacent to the pressing surface 31 coincides with one of the two observation holes 10, and the circumferential position of the portion of the radial outer surface of the other engaging element 5 (for example, the lower left side in Figure 3) that is not adjacent to the pressing surface 31 coincides with the other observation hole 10. Specifically, the two observation holes 10 are located at two radially opposite positions on the side plate portion 8. In addition, the circumferential length of the shortest portion of each observation hole 10 is approximately 24 degrees.

[0059] In this example, the side plate portion 8 has a cylindrical surface portion 11 on its inner circumferential surface. The side plate portion 8 also has an inwardly projecting flange portion 12 at one axial end of the cylindrical surface portion 11, projecting radially inward, and has screw holes 13 opening at multiple locations in the circumferential direction on the other axial side surface.

[0060] The pressed member 2 can be constructed as a single integrated unit, or it can be constructed by combining multiple parts. When the pressed member 2 is constructed from multiple parts, for example, the opening of a cylindrical member having a main body 7 can be closed by a lid member having a side plate 8. In this case, an observation hole 10 is provided in the lid member (side plate 8). In this example, the pressed member 2 is constructed as a single integrated unit.

[0061] The reverse input blocking clutch 1 in this example may also be further equipped with a cover member that closes the opening on one axial side of the main body 7 of the pressed member 2. In this case, the pressed member 2 and the cover member are fitted together (spigot fitting) without rattle by fitting the cover member to the axial end of the main body 7, thereby positioning the pressed member 2 and the cover member radially, and then connecting them to each other with a connecting member such as a bolt.

[0062] [Input Member] The input member 3 has an input-side engaging portion 14 located radially inward of the pressed surface 6 and is arranged coaxially with the pressed surface 6.

[0063] The input member 3 is connected to an input-side mechanism such as an electric motor on one axial side, and rotational torque is input to it. Specifically, the input member 3 can be made up of the output shaft of the input-side mechanism, or it can be made up as a separate member from the output shaft and fixed coaxially to the output shaft.

[0064] The input-side engaging portion 14 is provided on a part of the input member 3 that is radially outward from the rotational axis, and has a portion that engages, specifically contacts, with the input-side engaged portion 32 of the engaging element 5. The input-side engaging portion 14 is configured to engage (contact) its radially inner surface 16 with the radially inner surface 36 of the input-side engaged portion 32 as the input member 3 or engaging element 5 rotates.

[0065] In this example, the input member 3 has an input shaft portion 15 and an input flange portion 17, in addition to the input-side engaging portion 14.

[0066] The input shaft portion 15 is an element for connecting the input-side mechanism and the input member 3 to enable the transmission of rotational torque. In this example, the input shaft portion 15 has a cylindrical shape. The input member 3 is connected to the output shaft of the input-side mechanism, such as an electric motor, by non-circular engagement, such as spline engagement, between the inner circumferential surface of the input shaft portion 15 and the outer circumferential surface of the output shaft of the input-side mechanism.

[0067] The input flange portion 17 is an element for positioning the input-side engaging portion 14 at a location radially outward from the rotation center of the input member 3. In this example, the input flange portion 17 protrudes radially outward from the outer circumferential surface of the other axial end of the input shaft portion 15 over its entire circumference.

[0068] The input-side engaging portion 14 is an element that, when rotational torque is applied to the input member 3, engages with the input-side engaged portion 32 of the engaging element 5, causing the engaging element 5 to rotate in the same direction as the input torque. In this example, the input-side engaging portion 14 protrudes axially toward the other side from a portion of the other axial side of the input flange portion 17 that is radially outward from the center of rotation.

[0069] The shape of the input-side engaging portion 14 is not limited, as long as it is configured to engage with the input-side engaged portion 32 of the engaging element 5.

[0070] For example, the input-side engaging portion 14 may have an end face shape that is symmetrical with respect to the circumferential direction, or it may have an end face shape that is asymmetrical with respect to the circumferential direction. In this example, the input-side engaging portion 14 has an end face shape that is symmetrical with respect to the circumferential direction.

[0071] For example, the input-side engaging portion 14 can have a partially annular shape, a substantially trapezoidal shape, or a similar end face shape, where the length in the second direction increases as it moves outward in the first direction when viewed from the axial direction. In this example, the input-side engaging portion 14 has an end face shape similar to a substantially trapezoidal shape, and the intermediate portion in the second direction of the radially inner surface 16 of the input-side engaging portion 14 is made up of a flat surface perpendicular to the line connecting the central axis O of the input member 3 and the center of the input-side engaging portion 14 when viewed from the axial direction, and the portions on both sides in the second direction are made up of partially cylindrical convex surfaces that are inclined in the direction toward the outward direction in the first direction as they move toward both sides in the second direction. The radially outer surface 18 of the input-side engaging portion 14 is made up of a partially cylindrical convex surface centered on the central axis O.

[0072] The number of input-side engaging portions 14 is determined according to the number of engaging elements 5. If the engaging element 5 is composed of multiple engaging elements 5, the input-side engaging portions 14 are also composed of multiple input-side engaging portions 14.

[0073] In this example, the engaging element 5 is composed of two engaging elements 5. Therefore, the input-side engaging portion 14 is composed of two input-side engaging portions 14, corresponding to the number of engaging elements 5. The two input-side engaging portions 14 are positioned at two radially opposite locations on the other axial side of the input flange portion 17, and are spaced apart from each other with respect to the radial direction of the input member 3.

[0074] The input member 3 can be rotatably supported by the fixed portion or by the pressed member 2 which is supported and fixed to the fixed portion. In this example, the input member 3 is rotatably supported by a motor housing which is supported and fixed to the fixed portion via the motor output shaft of the electric motor 58.

[0075] [Output Member] The output member 4 has an output-side engaging portion 19 that is located radially inward from the input-side engaging portion 14, and is arranged coaxially with the pressed surface 6. In other words, the output member 4 is also arranged coaxially with the input member 3.

[0076] The output member 4 is connected to an output mechanism such as a reduction gear on the other axial side, and is configured to output rotational torque to the output mechanism as it rotates. Specifically, the output member 4 can be made up of the input shaft of the output mechanism, or it can be made up as a separate member from the input shaft and fixed coaxially to the input shaft. In this example, the output member 4 is fixed coaxially to the drive member 54 of a belt-type torque transmission device 52.

[0077] The output-side engaging portion 19 has a portion that engages with the output-side engaged portion 33 of the engaging element 5, and is an element that receives rotational torque from the engaging element 5 when rotational torque is input to the input member 3 and the engaging element 5 rotates. Furthermore, when rotational torque is input in reverse to the output member 4, it engages with the output-side engaged portion 33 of the engaging element 5 and rotates the engaging element 5 in the same direction as the reverse input torque.

[0078] The portion of the output-side engaging portion 19 that engages with the output-side engaged portion 33 of the engaging element 5 is located radially inward from the input-side engaging portion 14 and radially outward from the rotational axis O of the output member 4, and is positioned to engage with the output-side engaged portion 33 of the engaging element 5. The output-side engaging portion 19 is configured to engage (contact) its outer circumferential surface with the output-side engaged portion 33 as the output member 4 or engaging element 5 rotates.

[0079] The output-side engaging portion 19 has a cam function. The distance from the rotational axis of the output member 4 to the outer circumferential surface of the output-side engaging portion 19, which is the part that engages with the output-side engaged portion 33, is not constant in the circumferential direction.

[0080] The number of parts of the output-side engaging portion 19 that engage with the output-side engaged portion 33 is determined according to the number of engaging elements 5. When the engaging element 5 is composed of multiple engaging elements 5, the output-side engaging portion 19 is also configured to have multiple engaging parts. In this example, the output-side engaging portion 19 is configured to have two parts that engage with the output-side engaged portion 33, in accordance with the number of engaging elements 5.

[0081] When the output-side engaging portion 19 is cut by a virtual plane perpendicular to the rotational axis O of the output member 4, the cross-sectional shape of the output-side engaging portion 19 is arbitrary as long as the output-side engaging portion 19 has a cam function, and can be, for example, a square, rectangle, parallelogram, trapezoid, or other quadrilateral, oval, or a shape similar to these quadrilaterals or ovals.

[0082] In this example, the output-side engaging portion 19 has a substantially rectangular cross-sectional shape, as shown in Figure 5, when cut by a virtual plane perpendicular to the rotational axis O of the output member 4. More specifically, the outer circumferential surface of the output-side engaging portion 19 is composed of two parallel flat surfaces 20 and two convex curved surfaces 21, each partially cylindrical in shape.

[0083] In this example, the output-side engaging portion 19 is symmetrical with respect to a virtual plane that passes through the rotational axis O of the output member 4 and is perpendicular to the two flat surfaces 20. Furthermore, the output-side engaging portion 19 is symmetrical with respect to a virtual plane that passes through the rotational axis O of the output member 4 and is parallel to the two flat surfaces 20. That is, the output-side engaging portion 19 has a shape that is twice symmetrical with respect to the central axis of the output member 4. The output-side engaging portion 19 is located radially inside the two input-side engaging portions 14, positioned between the output-side engaged portions 33 of the two engaging elements 5, and passes through the through-hole 62 of the spacer 42.

[0084] In this example, the output member 4 has an output-side engaging portion 19, as well as an output shaft portion 22 and a small-diameter shaft portion 23.

[0085] The output shaft portion 22 is an element for connecting the output member 4 and the input portion of the output mechanism in a manner that can transmit rotational torque.

[0086] The output shaft portion 22 is arranged coaxially with the output-side engaging portion 19. The output-side engaging portion 19 protrudes in the axial direction from the center of the end face 24 on one axial side of the output shaft portion 22. The end face 24 on one axial side of the output shaft portion 22 is composed of a flat surface perpendicular to the central axis of the output member 4.

[0087] In this example, the output shaft portion 22 has a stepped cylindrical shape. Specifically, the output shaft portion 22 has a large diameter portion 25, a medium diameter portion 26, and a small diameter portion 27 in order from one side in the axial direction. The large diameter portion 25 has a flange portion 28 that protrudes radially outward along its entire circumference in the axial middle portion of its outer circumferential surface. In this example, the drive member 54 of the torque transmission device 52 is fitted and fixed to the medium diameter portion 26.

[0088] The small-diameter shaft portion 23 is an element for engaging the stopper member 43, which prevents the engaging element 5 and the spacer 42 from moving in one axial direction. The small-diameter shaft portion 23 has a cylindrical shape and protrudes in one axial direction from the center of the end face on one axial side of the output-side engaging portion 19.

[0089] The output member 4 is rotatably supported by the fixed portion or by the pressed member 2 which is supported and fixed to the fixed portion. In this example, the output member 4 is rotatably supported by the pressed member 2. Specifically, the large-diameter portion 25 of the output shaft portion 22 is rotatably supported by the pressed member 2 by a radial rolling bearing 29a. The outer ring of the radial rolling bearing 29a is fitted snugly into the cylindrical surface portion 11 provided on the inner circumferential surface of the side plate portion 8 of the pressed member 2, and the inner ring of the radial rolling bearing 29a is fitted snugly onto the outer circumferential surface of the large-diameter portion 25. Furthermore, the radial rolling bearing 29a is axially sandwiched between a flange portion 28 provided on the outer circumferential surface of the large-diameter portion 25 and an inward-facing flange portion 12 provided on the inner circumferential surface of the pressed member 2.

[0090] The small-diameter portion 27 of the output shaft 22 is rotatably supported by a radial rolling bearing 29b on a support member 45, which will be described later. The other end face of the small-diameter portion 27 of the output shaft 22 on the axial side is exposed and not covered by the support member 45.

[0091] In this example, the output member 4 is provided with a corner radius 30 having a concave arc cross-sectional shape at the connection point between the axial end face 24 of the output shaft portion 22 and the outer circumferential surface of the output-side engaging portion 19. The corner radius 30 relieves the stress acting on the connection point between the axial end face 24 of the output shaft portion 22 and the outer circumferential surface of the output-side engaging portion 19.

[0092] The output member 4 may have a marker 61 that allows confirmation of the rotational phase of the output member 4. The marker 61 is an element that allows easy determination of the rotational phase of the output-side engaging portion 19 from the outside.

[0093] By providing the marker 61, it becomes easier to align the circumferential position of the observation hole 10 of the pressed member 2 with the circumferential position of the portion of the radially outer surface of the engaging element 5 that is circumferentially away from the pressing surface 31, in order to temporarily disable the reverse input blocking function of the reverse input blocking clutch 1.

[0094] The type and location of the marker 61 are not particularly limited, as long as they can be seen from the outside. For example, the marker 61 can be a recess or a protrusion, a mark made with paint or an oil-based pen, or an engraving. In this example, the marker 61 is provided on the other end face in the axial direction of the output shaft portion 22 (small diameter portion 27) of the output member 4, and is composed of a groove extending in a direction parallel to the flat surface 20.

[0095] [Engaging element] The engaging element 5 has a pressing surface 31 facing the pressed surface 6, an input-side engaged portion 32 that can engage with the input-side engaging portion 14, and an output-side engaged portion 33 that can engage with the output-side engaging portion 19, and is arranged to be movable in a first direction which is the near-far direction relative to the pressed surface 6.

[0096] When rotational torque is input to the input member 3, the engaging element 5 moves away from the pressed surface 6 in the first direction based on the input-side engaging portion 14 engaging with the input-side engaged portion 32, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output-side engaged portion 33 with the output-side engaging portion 19. Conversely, when rotational torque is input in reverse to the output member 4, the engaging element 5 presses the pressing surface 31 against the pressed surface 6 based on the output-side engaging portion 33 engaging with the output-side engaged portion 19, thereby frictionally engaging the pressing surface 31 with the pressed surface 6.

[0097] The engaging element 5 may consist of one engaging element 5 or two or more engaging elements 5, as long as it has the above configuration.

[0098] The engaging element 5 can be manufactured by any method. For example, the engaging element 5 can be manufactured by pressing, sintering, forging, casting, and / or machining. In this example, the engaging element 5 is a press-formed metal plate manufactured by pressing.

[0099] The shape of the engaging element 5 is arbitrary as long as it comprises a pressing surface 31, an input-side engaged portion 32, and an output-side engaged portion 33, and can achieve the above-mentioned functions; therefore, a wide range of conventional engaging element shapes can be adopted.

[0100] In this example, the engaging element 5 is composed of two engaging elements 5. Each engaging element 5 has the function of an engaging element 5. Each engaging element 5 has a substantially semicircular end face shape when viewed from the axial direction and has a symmetrical shape with respect to the width direction. The configuration of each engaging element 5 will be described below.

[0101] The pressing surface 31 is provided on the radially outer surface of the engaging element 5 facing the pressed surface 6. The shape and size of the pressing surface 31 are arbitrary as long as they can frictionally engage with the pressed surface 6. The pressing surface 31 can be made up of the entire radially outer surface of the engaging element 5, or it can be made up of a part of it. One pressing surface 31 can be provided for one engaging element 5, or multiple pressing surfaces 31 can be provided. The radius of curvature of the pressing surface 31 can be the same as the radius of curvature of the pressed surface 6, or it can be smaller than the radius of curvature of the pressed surface 6.

[0102] In this example, the pressing surface 31 is composed of two pressing surfaces 31 located at two positions on the radially outer surface of the engaging element 5 that are spaced apart from each other in the circumferential direction. Each pressing surface 31 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the surface to be pressed 6.

[0103] The portion of the radially outer surface of the engaging element 5 that is circumferentially separated from the two pressing surfaces 31 is located radially inward from a virtual circle that is centered on the rotation center O of the input member 3 and tangent to the two pressing surfaces 31, when viewed from the axial direction. In other words, when the two pressing surfaces 31 are in contact with the surface to be pressed 6, the portion that is circumferentially separated from the two pressing surfaces 31 does not come into contact with the surface to be pressed 6.

[0104] In this example, the engaging element 5 has a non-contact surface 34 on its radially outer surface, located between the two pressing surfaces 31, which does not come into contact with the pressed surface 6 when the two pressing surfaces 31 are in contact with the pressed surface 6. In this example, the non-contact surface 34 is made up of a flat surface perpendicular to the radial direction of the engaging element 5. Therefore, when the two pressing surfaces 31 are in contact with the pressed surface 6, a gap 35 is formed between the pressed surface 6 and the non-contact surface 34, when viewed from the axial direction, which is approximately crescent-shaped or approximately arch-shaped.

[0105] In this example, the non-contact surface 34 can be defined as the portion of the radially outer surface of the engaging element 5 that is circumferentially separated from the pressing surface 31. In this case, the circumferential length of the gap 35 is also related to the rotational tolerance required for the output member 4 when the reverse input blocking function is temporarily released. For this reason, it is preferable to arrange the two pressing surfaces 31 so as not to hinder the function of providing the two pressing surfaces 31, and to form a non-contact surface 34 that can sufficiently secure the circumferential length of the gap 35. For example, the distance between the two pressing surfaces 31 provided on each engaging element 5 is preferably in the range of 120 degrees to 160 degrees, and more preferably in the range of 135 degrees to 145 degrees, in terms of the central angle around the central axis of the pressed surface 6. In this example, the distance between the two pressing surfaces 31 provided on each engaging element 5 is 140 degrees, in terms of the central angle around the central axis of the pressed surface 6.

[0106] The pressing surface 31 preferably has a surface property that results in a higher coefficient of friction with respect to the pressed surface 6 than the other parts of the engaging element 5. Furthermore, the pressing surface 31 can be integrally formed with the other parts of the engaging element 5, or it can be formed from the surface of a friction material fixed to the other parts of the engaging element 5 by adhesive or other means.

[0107] The input-side engaged portion 32 engages with the input-side engaged portion 14 as the input member 3 rotates, and is an element that receives the rotational torque input from the input member 3. The shape of the input-side engaged portion 32 is not limited as long as it is configured to be able to engage with the input-side engaged portion 14.

[0108] In this example, the input-side engaged portion 32 is provided in the radially intermediate portion of the widthwise center of the engaging element 5. More specifically, the input-side engaged portion 32 is composed of a through hole that penetrates the radially intermediate portion of the widthwise center of the engaging element 5 in the axial direction.

[0109] The input-side engaged portion 32 is sized to allow the input-side engaged portion 14 to be loosely inserted. Therefore, when the input-side engaged portion 14 is inserted inside the input-side engaged portion 32, there are gaps between the input-side engaged portion 14 and the inner surface of the input-side engaged portion 32 in the width direction and the radial direction of the engaging element 5. As a result, the input-side engaged portion 14 can be displaced relative to the input-side engaged portion 32 in the rotational direction of the input member 3, and the input-side engaged portion 32 can be displaced relative to the input-side engaged portion 14 in the radial direction of the engaging element 5.

[0110] In this example, the radially inner surface 36 of the inner surface of the input-side engaged portion 32, which faces radially outward, is composed of a flat surface perpendicular to the first direction, and the radially outer surface 37 of the inner surface of the input-side engaged portion 32, which faces radially inward, is composed of a curved surface having a substantially arc-shaped contour or a composite surface having a substantially V-shaped contour when viewed from the axial direction. The circumferential surface 38 connecting the ends on both sides of the radially inner surface 36 in the second direction and the ends on both sides of the radially outer surface 37 in the second direction is composed of a partially cylindrical concave curved surface.

[0111] The output-side engaged portion 33 engages with the output-side engaged portion 19 as the engaging element 5 rotates, and is an element for outputting the rotational torque input from the input member 3 to the engaging element 5 to the output member 4. The shape of the output-side engaged portion 33 is not limited as long as it is configured to engage with the output-side engaged portion 19. In this example, the output-side engaged portion 33 is provided at the center in the width direction of the radially inner surface of the engaging element 5.

[0112] In this example, the engaging element 5 has a flat surface portion 39 on its radially inner surface that is perpendicular to the radial direction of the engaging element 5, and has two protrusions 40 projecting radially inward at two positions on the flat surface portion 39 in the width direction of the engaging element 5. The output-side engaged portion 33 is composed of the portion of the flat surface portion 39 that is located between the two protrusions 40 in the width direction. In this example, the width dimension of the output-side engaged portion 33, i.e., the distance between the two protrusions 40, is larger than the width dimension of the flat surface 20 of the output-side engaging portion 19.

[0113] In the reverse input blocking clutch 1 of this example, the pressing surfaces 31 of the two engaging elements 5 are oriented radially toward opposite sides, and the flat surfaces 39 are facing each other, with each engaging element 5 positioned radially inward of the pressed member 2, allowing movement in the first direction. Furthermore, the two input-side engaging portions 14 of the input member 3, positioned on one axial side, are inserted axially into the respective input-side engaged portions 32 of the two engaging elements 5, and the output-side engaging portion 19 of the output member 4, positioned on the other axial side, is inserted axially between the output-side engaged portions 33 of the two engaging elements 5. In other words, the two engaging elements 5 are positioned so that their respective output-side engaged portions 33 sandwich the output-side engaging portion 19 from the radial outside.

[0114] With the two engaging elements 5 positioned radially inward of the pressed member 2, the inner diameter of the pressed surface 6 and the radial dimensions of the engaging elements 5 are regulated such that a gap exists in at least one of the following areas: the space between the pressed surface 6 and the two pressing surfaces 31, and the space between the tip faces of the two combinations of protrusions 40 formed by the two protrusions 40 of the two engaging elements facing each other.

[0115] [Biasing Member] The reverse input blocking clutch 1 in this example further comprises a biasing member 41 as an optional component.

[0116] The biasing member 41 elastically biases the engaging element 5 toward the pressed surface 6. The biasing member 41 can be made of a spring such as a leaf spring, coil spring, or disc spring, or an elastic material such as rubber, elastomer, or synthetic resin. The number of biasing members 41 is not particularly limited and is appropriately determined according to the number of engaging elements 5.

[0117] In this example, the biasing member 41 is composed of two biasing members 41 positioned at two locations in the width direction between the radially inner surfaces of the two engaging elements 5, and each biasing member 41 is composed of a compression coil spring. A protrusion 40 is inserted into the inside of both ends in the extension direction of each biasing member 41. This prevents each biasing member 41 from falling out of the space between the two engaging elements 5.

[0118] The two biasing members 41 elastically bias the two engaging elements 5 toward the pressed surface 6 by the force of their elastic restoring. As a result, in the neutral state where no torque is applied to either the input member 3 or the output member 4, the pressing surfaces 31 of the two engaging elements 5 come into contact with the pressed surface 6. This ensures that even when no rotational torque is being input in reverse to the output member 4, the pressing surfaces 31 and the pressed surface 6 engage in friction, maintaining the reverse input blocking function of the reverse input blocking clutch.

[0119] [Spacers and stopper members] The reverse input blocking clutch 1 in this example further comprises two spacers 42 and a stopper member 43 as optional components.

[0120] Each spacer 42 has the function of restricting the axial position of the engaging element 5 with respect to the output member 4.

[0121] In this example, each spacer 42 is constructed in a flat plate shape and has an end face shape that is approximately oval or rectangular when viewed from the axial direction. Each spacer 42 has a through hole 44 through which the output-side engaging portion 19 can be inserted without rattling. Each spacer 42 is positioned on both axial sides of the two engaging elements 5 with the output-side engaging portion 19 inserted through the through hole 44 without rattling.

[0122] The stopper member 43 has the function of preventing one of the two spacers 42, the axial spacer 42, from moving axially to the axial side and falling off the output member 4.

[0123] In this example, the stopper member 43 is made up of a segmented annular retaining ring. The stopper member 43 is locked into a locking groove provided on the outer circumferential surface of the other axial end of the small diameter shaft portion 23 of the output member 4.

[0124] [Support Member] The reverse input blocking clutch 1 in this example further comprises a support member 45 as an optional component.

[0125] The support member 45 is an element for rotatably supporting the other axial end (small diameter portion 27) of the output shaft portion 22.

[0126] The support member 45 comprises a cylindrical bearing holder 46, a partial cylindrical portion 47 extending axially from a single circumferential position at one end of the bearing holder 46 on one axial side, and an outward flange portion 48 extending radially outward from one end of the partial cylindrical portion 47 on one axial side.

[0127] The support member 45 is supported and fixed to the pressed member 2 by screwing a bolt 50, which is inserted through a through hole 49 provided in the outward flange portion 48, into a threaded hole 13 provided in the pressed member 2.

[0128] The other axial end (small diameter portion 27) of the output shaft portion 22 is rotatably supported by the support member 45 via a radial rolling bearing 29b held by the bearing holding portion 46.

[0129] In the illustrated example, the radial rolling bearings 29a and 29b that rotatably support the output shaft 22 are each ball bearings using balls as rolling elements. However, the radial rolling bearings for supporting the output shaft 22 can also be constructed using tapered roller bearings or cylindrical roller bearings using tapered rollers as rolling elements. Furthermore, different types of bearings can be used for the radial rolling bearings 29a and 29b.

[0130] <Explanation of the operation of the reverse input blocking clutch> The operation of the reverse input blocking clutch 1 in the normal state, that is, when the reverse input blocking function is enabled, will be explained using Figures 6 and 7. Note that Figures 6 and 7 omit the biasing member 41 and exaggerate the radial gap between the input member 3 and the output member 4 and the two engaging elements 5.

[0131] When rotational torque is applied to the input member 3, the two engaging elements 5 move away from the pressed surface 6, regardless of the rotation direction of the input member 3. More specifically, as shown in Figure 6, the input-side engaging portion 14 rotates inside the input-side engaged portion 32 in the rotation direction of the input member 3 (counterclockwise in the example of Figure 6).

[0132] This reduces the gap between the radially inner surface 16 of the input-side engaging portion 14 and the radially inner surface 36 of the input-side engaged portion 32, causing the radially inner surface 16 of the input-side engaging portion 14 to come into contact with the radially inner surface 36 of the input-side engaged portion 32.

[0133] From this state, as the input member 3 rotates further, the radially inner surface 16 of the input-side engaging portion 14 presses the radially inner surface 36 of the input-side engaged portion 32 radially inward, causing the engaging element 5 to move away from the pressed surface 6. That is, the two engaging elements 5 move radially inward, moving closer to each other based on their engagement with the input member 3, causing the radially inner surfaces of the two engaging elements 5 to approach each other, and the output-side engaged portion 19 of the output member 4 is clamped from both radial sides by the output-side engaged portions 33 of the two engaging elements 5.

[0134] In this way, the output member 4 is rotated so that the flat surface 20 of the output-side engaging portion 19 is parallel to the output-side engaged portion 33, while the output-side engaging portion 19 and the output-side engaged portion 33 of the engaging element 5 are engaged without any rattle. As a result, the rotational torque input to the input member 3 is transmitted to the output member 4 via the two engaging elements 5 and output from the output member 4.

[0135] When rotational torque is applied in reverse to the output member 4, the two engaging elements 5 move toward the pressed surface 6, regardless of the rotation direction of the output member 4. Specifically, as shown in Figure 7, the output-side engaging portion 19 rotates in the direction of rotation of the output member 4 (clockwise in the example of Figure 7) inside the output-side engaged portions 33 of the two engaging elements 5. The flat surface 20 of the outer circumferential surface of the output-side engaging portion 19 presses the output-side engaged portions 33 radially outward, causing the two engaging elements 5 to move toward the pressed surface 6.

[0136] In other words, the two engaging elements 5 move radially outward, away from each other, based on their engagement with the output member 4, so that the pressing surfaces 31 of the two engaging elements 5 come into contact with the pressed surface 6 and frictionally engage with the pressed surface 6.

[0137] As a result, the rotational torque reversed into the output member 4 is either completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque reversed into the output member 4 is transmitted to the input member 3 and the rest is blocked.

[0138] In order to completely block the rotational torque that is reverse-input to the output member 4 and prevent it from being transmitted to the input member 3, the engaging element 5 is braced (clamped) between the output-side engaging part 19 and the pressed member 2 so that the pressing surface 31 of the engaging element 5 does not slide (rotate relative to) the pressed surface 6, thereby locking the output member 4.

[0139] To ensure that only a portion of the rotational torque inverted to the output member 4 is transmitted to the input member 3 and the remainder is blocked, the engaging element 5 is braced (clamped) between the output-side engaging portion 19 and the pressed member 2 so that the pressing surface 31 of the engaging element 5 slides against the pressed surface 6, thereby semi-locking the output member 4.

[0140] In the reverse input blocking clutch 1 of this example, the size of the gaps between each component is adjusted so that the above operation is possible. In particular, when the pressing surfaces 31 of the two engaging elements 5 are in contact with the pressed surface 6, a gap exists between the radially inner surface 16 of the input-side engaging portion 14 and the radially inner surface 36 of the input-side engaged portion 32.

[0141] This prevents the radial outward movement of the engaging element 5 from being blocked by the input-side engaging part 14 when rotational torque is input in reverse to the output member 4, and also ensures that even after the pressing surface 31 contacts the pressed surface 6, the surface pressure acting on the contact area between the pressing surface 31 and the pressed surface 6 changes according to the magnitude of the rotational torque input in reverse to the output member 4, thereby ensuring that the output member 4 is properly locked or partially locked.

[0142] Furthermore, the biasing member 41 elastically biases the two engaging elements 5 toward the pressed surface 6, so that even in a neutral state where no torque is applied to either the input member 3 or the output member 4, the pressing surfaces 31 of the two engaging elements 5 are in contact with the pressed surface 6. As a result, even when no rotational torque is being input in reverse to the output member 4, the pressing surfaces 31 and the pressed surface 6 are frictionally engaged, maintaining the reverse input blocking function of the reverse input blocking clutch.

[0143] <Explanation of how to temporarily disable the reverse input blocking function> In the reverse input blocking clutch 1 of this disclosure, an observation hole 10 is provided in the side plate portion 8 of the pressed member 2, so that the reverse input blocking function, which either does not transmit the rotational torque reversed into the output member 4 to the input member 3, or transmits only a part of it to the input member 3 and blocks the rest, can be temporarily disabled. That is, as shown in Figure 8, by inserting a tool 51 radially inward into the main body portion 7 through the observation hole 10 and moving the engaging element 5 radially inward with the tool 51, the pressing surface 31 is separated from the pressed surface 6, thereby temporarily disabling the reverse input blocking function.

[0144] Specifically, first, the input member 3 is rotated. Rotating the input member 3 releases the locked or semi-locked state of the output member 4, making it possible to rotate the input member 3, the engaging element 5, and the output member 4 together. By rotating the input member 3, the circumferential position of the non-contact surface 34, in this example, which is the portion of the radially outer surface of the engaging element 5 that is circumferentially away from the pressing surface 31, is brought to approximately coincide with the circumferential position of the observation hole 10 provided in the side plate portion 8 of the pressed member 2. This operation is performed using the marker 61.

[0145] More specifically, by rotating the input member 3 while checking the marker 61, the output member 4 is rotated until the extension direction of the marker 61 is oriented approximately 90 degrees away from the circumferential center position of the observation hole 10. This causes the circumferential position of the non-contact surface 34 to roughly coincide with the circumferential position of the observation hole 10.

[0146] The operation of rotating the input member 3 so that the circumferential position of the non-contact surface 34 approximately coincides with the circumferential position of the observation hole 10 can be performed manually by an operator while visually confirming the marker 61, or it can be performed automatically by a robot.

[0147] Next, the tip (one end on the axial side) of the rod-shaped or plate-shaped tool 51 is inserted into the observation hole 10 located in the part of the observation hole 10 where the circumferential position coincides with the non-contact surface 34. Then, the tip of the tool 51 is inserted through the observation hole 10 into the gap 35 that exists between the pressed surface 6 and the non-contact surface 34.

[0148] Next, the tip of the tool 51 presses the non-contact surface 34 of the engaging element 5 radially inward, and by maintaining the pressing surface 31 separated from the pressed surface 6, the reverse input blocking function is temporarily disabled. In this state, the output member 4 can rotate within the range in which the tip of the tool 51 can move circumferentially inside the observation hole 10. The operation of pressing the non-contact surface 34 of the engaging element 5 radially inward with the tip of the tool 51 can be performed by moving the tip of the tool 51 itself radially inward, or by using the tapered guide surface provided on the tip of the tool 51.

[0149] <Explanation of the structure of the torque transmission device and its tension adjustment method> The reverse input blocking clutch 1 of this disclosure can be incorporated into various mechanical devices. Examples of mechanical devices into which the reverse input blocking clutch 1 can be incorporated include a torque transmission device that transmits the rotational motion of a drive source to a driven part as rotational motion, or a mechanical device such as an electric jack that converts the rotational motion of a drive source into linear motion and transmits it to a driven part.

[0150] While not limited to this, a torque transmission device can be employed that transmits torque between a driving member and a driven member arranged parallel to each other via a flexible annular transmission member, such as a belt-type or chain-type torque transmission device.

[0151] The torque transmission device 52 includes, in addition to the reverse input blocking clutch 1, a torque input section 53, a drive member 54, a driven member 55, a transmission member 56, and an adjustment member 57. In this example, the torque transmission device 52 is configured as a belt-type torque transmission device.

[0152] The torque input section 53 is rotationally driven by a drive source such as an electric motor 58 or an engine. In this example, the torque input section 53 is composed of the input member 3 of the reverse input blocking clutch 1 and is rotationally driven by the electric motor 58.

[0153] The drive member 54 is arranged coaxially with the torque input unit 53.

[0154] The driven member 55 is arranged parallel to the driving member 54. The driven member 55 is connected to the driven part in a manner that allows torque to be transmitted.

[0155] The transmission member 56 is annular in shape, spans between the driving member 54 and the driven member 55, and is flexible.

[0156] The adjustment member 57 is pressed against the transmission member 56, applying tension to the transmission member 56. The adjustment member 57 is configured to allow adjustment of the force with which it is pressed against the transmission member 56. In this example, the adjustment member 57 is configured to apply tension to the transmission member 56 from the outside. However, the adjustment member 57 can also be configured to apply tension to the transmission member 56 from the inside.

[0157] In this example, the drive member 54, the driven member 55, and the adjusting member 57 are each made up of pulleys, and the transmission member 56 is made up of an endless belt. In contrast, in a chain-type torque transmission member, the drive member, the driven member, and the adjusting member are each made up of sprockets, and the transmission member is made up of a chain.

[0158] The reverse input blocking clutch 1 is positioned between the output shaft of the electric motor 58 and the drive member 54.

[0159] The input member 3 is composed of a torque input section 53, or it is composed as a separate component from the torque input section 53 and is fixed coaxially with respect to the torque input section 53. In this example, the input member 3 is composed of a torque input section 53.

[0160] The output member 4 is either integrated with the drive member 54, or it is configured as a separate component from the drive member 54 and is fixed coaxially to the drive member 54. In this example, the drive member 54, configured as a separate component from the output member 4, is externally fitted and fixed to the output shaft portion 22 (medium diameter portion 26) of the output member 4.

[0161] The torque transmission device 52 of this disclosure incorporates a reverse input blocking clutch 1 between the output shaft of the electric motor 58 and the drive member 54. Therefore, even if the power supply to the electric motor 58 is stopped, the position or orientation of the driven part, which is connected to the driven member 55 in a manner that allows torque transmission, can be maintained.

[0162] In the torque transmission device 52 of this disclosure, a tool 51 is inserted radially inward into the main body 7 through the observation hole 10, and the engaging element 5 is moved radially inward by the tool 51, thereby separating the pressing surface 31 from the pressed surface 6. The tension of the transmission member 56 is then adjusted by adjusting the pressing force of the adjustment member 57 against the transmission member 56.

[0163] In other words, the reverse input blocking function of the reverse input blocking clutch 1 is temporarily disabled, and the rotation of the output member 4 is permitted within the range in which the tip of the tool 51 can move circumferentially inside the observation hole 10, and / or within the range in which the engaging element 5 can move circumferentially relative to the tip of the tool 51, thereby allowing the rotation of the drive member 54. This allows a change in the amount of tension on the transmission member 56 by the adjusting member 57 due to a change in the pressing force of the adjusting member 57 on the transmission member 56. Therefore, the tension of the transmission member 56 can be adjusted with a relatively small force without changing the position or orientation of the driven part connected to the driven member 55.

[0164] After adjusting the tension of the transmission member 56 to the desired size, the tool 51 is withdrawn from the observation hole 10. As a result, the elasticity of the biasing member 41 causes the engaging element 5 to move radially outward, and the pressing surface 31 is pressed against the surface to be pressed 6.

[0165] [Second Example] A second example of the embodiment of the present disclosure will be described with reference to Figures 12 and 13.

[0166] In this example, the number of observation holes 10a provided in the side plate portion 8a of the pressed member 2a, and the support structure of the output member 4a, differ from the structure of the first example.

[0167] In the reverse input blocking clutch 1a of this example, the side plate portion 8a has four observation holes 10a. The four observation holes 10a are provided at four equally spaced locations in the circumferential direction of the side plate portion 8a.

[0168] In this example, the circumferential position of the non-contact surface 34 of one of the two engaging elements 5 is aligned with one of the four observation holes 10a. Then, the circumferential position of the observation hole 10a located radially opposite to the aforementioned observation hole 10a among the remaining three observation holes 10a coincides with the circumferential position of the non-contact surface 34 of the other engaging element 5.

[0169] In this example, the angle at which the input member 3 is rotated in order to align the circumferential position of the observation hole 10a with the circumferential position of the non-contact surface 34 can be kept smaller compared to the structure of the first example.

[0170] In this example, one axial position of the output shaft portion 22a of the output member 4a is rotatably supported with respect to the pressed member 2a by a single bearing device 59.

[0171] Specifically, the axial end (large diameter portion 25a) of the output shaft portion 22a is rotatably supported by a bearing device 59 with respect to the inner circumferential surface of the inner diameter cylindrical portion 60 that extends from the radially inner end of the side plate portion 8a toward the other axial direction.

[0172] In the illustrated example, the bearing device 59 is composed of back-to-back double-row angular contact ball bearings. However, the bearing device 59 can also be composed of face-to-face double-row angular contact ball bearings, double-row tapered roller bearings, double-row cylindrical roller bearings, and the like.

[0173] The reverse input blocking clutch 1a in this example can reduce the number of parts compared to the reverse input blocking clutch 1 in the first example. Furthermore, since it does not have a support member 45, the transmission member 56 can be connected to the drive member 54 after the reverse input blocking clutch 1a has been assembled to the machine. This makes the assembly and maintenance work of the machine easier.

[0174] The other components and effects of the second example are the same as those of the first example.

[0175] The first and second embodiments of this disclosure can be combined as appropriate, as long as they do not create a contradiction.

[0176] 1, 1a Reverse input blocking clutch 2, 2a Pressed member 3 Input member 4, 4a Output member 5 Engaging element 6 Pressed surface 7 Main body 8, 8a Side plate 9 Protrusion 10, 10a Observation hole 11 Cylindrical surface 12 Inward flange 13 Screw hole 14 Input side engaging part 15 Input shaft 16 Radial inner surface 17 Input flange 18 Radial outer surface 19 Output side engaging part 20 Flat surface 21 Convex curved surface 22, 22a Output shaft 23 Small diameter shaft 24 End face 25, 25a Large diameter part 26 Medium diameter part 27 Small diameter part 28 Flange 29a, 29b Radial rolling bearing 30 Corner radius part 31 Pressing surface 32 Input side engaged part 33 Output side engaged portion 34 Non-contact surface 35 Gap 36 Radial inner surface 37 Radial outer surface 38 Circumferential surface 39 Flat surface portion 40 Convex portion 41 Biasing member 42 Spacer 43 Stopper member 44 Through hole 45 Support member 46 Bearing holding portion 47 Partial cylindrical portion 48 Outward flange portion 49 Through hole 50 Bolt 51 Tool 52 Torque transmission device 53 Torque input portion 54 Drive member 55 Driven member 56 Transmission member 57 Adjustment member 58 Electric motor 59 Bearing device 60 Inner diameter side cylindrical portion 61 Marker

Claims

1. A pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion arranged radially inward from the pressed surface, connected to an input-side mechanism on one axial side, and arranged coaxially with the pressed surface; an output member having an output-side engaging portion arranged radially inward from the input-side engaging portion, connected to an output-side mechanism on the other axial side, and arranged coaxially with the pressed surface; and an engaging element having a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and arranged to allow movement of the pressing surface in the near and far directions relative to the pressed surface, The engaging element, when rotational torque is input to the input member, moves radially away from the pressed surface based on the input-side engaging portion engaging with the input-side engaged portion, and transmits the rotational torque input to the input member to the output member by engaging the output-side engaged portion with the output-side engaging portion. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, causing the pressing surface to frictionally engage with the pressed surface. The pressed member comprises: a main body portion having the pressed surface on its inner circumferential surface; and a side plate portion extending radially inward from the axial end of the main body portion. The side plate portion has an observation hole that penetrates axially through a portion of the radial outer surface of the engaging element facing the pressed surface, including a portion whose radial position coincides with a portion that is circumferentially away from the pressing surface.

2. The reverse input blocking clutch according to claim 1, wherein the number of observation holes is an integer multiple of the number of engaging elements.

3. The reverse input blocking clutch according to claim 2, wherein the engaging element is composed of two engaging elements, and the circumferential position of the portion of the radial outer surface of one of the two engaging elements that is not adjacent to the pressing surface coincides with one of the observation holes, and the circumferential position of the portion of the radial outer surface of the other engaging element that is not adjacent to the pressing surface coincides with the other observation hole.

4. The pressing surface is composed of two pressing surfaces provided at two positions on the radial outer surface of the engaging element that are spaced apart from each other in the circumferential direction, and the engaging element has a non-contact surface on the radial outer surface between the two pressing surfaces in the circumferential direction that does not contact the surface to be pressed when the two pressing surfaces are in contact with the surface to be pressed, according to any one of claims 1 to 3.

5. The reverse input blocking clutch according to claim 4, wherein the non-contact surface is composed of a flat surface perpendicular to the radial direction of the engaging element.

6. The reverse input blocking clutch according to any one of claims 1 to 5, wherein the side plate portion extends radially inward from the other axial end of the main body portion.

7. The reverse input blocking clutch according to claim 6, wherein the output member is rotatably supported on the inner circumferential surface of the side plate portion by radial rolling bearings.

8. The reverse input shutoff clutch according to claim 6 or 7, wherein the output member has a mark that allows confirmation of the phase in the rotational direction of the output member.

9. A torque transmission device comprising: a torque input unit rotationally driven by a drive source; a drive member arranged coaxially with the torque input unit; a driven member arranged parallel to the drive member; a flexible annular transmission member spanning between the drive member and the driven member; an adjustment member pressed against the transmission member to apply tension to the transmission member; and a reverse input blocking clutch arranged between the torque input unit and the drive member, wherein the reverse input blocking clutch is configured as a reverse input blocking clutch according to any one of claims 1 to 8; the input member is configured as the torque input unit, or as a separate member from the torque input unit and fixed coaxially with respect to the torque input unit; and the output member is configured integrally with the drive member, or as a separate member from the drive member and fixed coaxially with respect to the drive member.

10. A method for adjusting the tension of a torque transmission device according to claim 9, comprising: inserting a tool radially inward into the main body through the observation hole; moving the engaging element radially inward with the tool, thereby separating the pressing surface from the pressed surface; and adjusting the pressing force of the adjustment member against the transmission member to adjust the tension of the transmission member.

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