Reverse-input blocking clutch

Abstract

[Problem] To achieve a structure that can prevent damage to a reverse-input blocking clutch and / or to a member constituting a mechanical device in which the reverse-input blocking clutch is incorporated, even when an excessively large torque is reversely inputted into an output member. [Solution] A pressed member 2 has: a fixed element 7 that does not rotate even during use; a movable element 8 that is supported radially inward of the fixed element 7 so as to be capable of rotating relative to the fixed element 7, and that has a pressed surface 6; and a limiting member 9 that is disposed between the fixed element 7 and the movable element 8. When a rotational torque reversely input into the output member 4 is less than or equal to a prescribed value, the limiting member 9 prevents rotation of the movable element 8 relative to the fixed element 7, whereas when the rotational torque reversely input into the output member 4 is greater than the prescribed value, the limiting member 9 allows the rotation of the movable element 8 relative to the fixed element 7.

Description

Reverse input blocking clutch

[0001] This disclosure relates to a reverse input blocking clutch that transmits rotational torque input to an input member to an output member, but does not transmit rotational torque input in reverse to an output member to the input member.

[0002] A reverse input blocking clutch 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 having the function of not transmitting rotational torque that is input in reverse to the output member to the input member.

[0003] Reverse input blocking clutches differ in the mechanism for blocking the rotational torque applied in reverse to the output member. They include a lock-type reverse input blocking clutch, which has a mechanism to prevent the output member from rotating when rotational torque is applied in reverse, and a free-type reverse input blocking clutch, which has a mechanism to allow the output member to spin freely when rotational torque is applied. The choice between a lock-type and a free-type reverse input blocking clutch is determined appropriately based on the application of the device in which the reverse input blocking clutch is incorporated.

[0004] In the lock-type reverse input blocking clutch described in International Publication No. 2019 / 026794, when rotational torque is input to an input member, the input-side engaging portion of the input member engages with the input-side engaged portion of the engaging element, causing the engaging element to move away from the pressed surface provided on the pressed member, and the output-side engaged portion of the engaging element engages with the output-side engaging portion of the output member, thereby transmitting the rotational torque input to the input member to the output member. On the other hand, when rotational torque is input in reverse to the output member, the output-side engaging portion of the output member engages with the output-side engaged portion of the engaging element, causing the engaging element to move towards the pressed surface, pressing the pressing surface against the pressed surface and frictionally engaging the pressing surface with the pressed surface.

[0005] International Publication No. 2019 / 026794 Brochure

[0006] In the reverse input blocking clutch described in International Publication No. 2019 / 026794, even if an excessively large torque is reversed input to the output member, the pressing surface cannot slide against the pressed surface, and the rotation of the output member is prevented. This can cause excessive force to be applied to the reverse input blocking clutch and / or the components of the machine in which the reverse input blocking clutch is incorporated, potentially leading to damage to those components.

[0007] The present disclosure aims to provide a reverse input blocking clutch structure that, when an excessively large torque is reverse-inputted to the output member, allows the output member to rotate, thereby preventing damage to the reverse input blocking clutch and / or the components constituting the mechanical device into which the reverse input blocking clutch is incorporated.

[0008] 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.

[0009] The member to be pressed has a surface to be pressed on its inner circumferential surface.

[0010] The input member has an input-side engaging portion located radially inward of the pressed surface and is arranged coaxially with the pressed surface.

[0011] The output member has an output-side engaging portion that is located radially inward from the input-side engaging portion and is arranged coaxially with the pressed surface.

[0012] 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 be movable in the radial direction.

[0013] 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.

[0014] In particular, in a reverse input blocking clutch according to one aspect of the present disclosure, the pressed member comprises: a fixed element that does not rotate even during use; a movable element having the pressed surface and arranged to be able to rotate relative to the fixed element; and a limiting member disposed between the fixed element and the movable element.

[0015] The limiting member prevents the relative rotation of the movable element with respect to the fixed element when the rotational torque input in reverse to the output member is less than or equal to a predetermined magnitude, while allowing the relative rotation of the movable element with respect to the fixed element when the rotational torque input in reverse to the output member is greater than a predetermined magnitude.

[0016] In a reverse input blocking clutch according to one aspect of the present disclosure, the movable element may be positioned radially inward of the fixed element.

[0017] In a reverse input blocking clutch according to one aspect of the present disclosure, the limiting member can be sandwiched radially between the inner circumferential surface of the fixed element and the outer circumferential surface of the movable element.

[0018] In one embodiment of the reverse input blocking clutch of the present disclosure, the limiting member may be composed of a tolerance ring comprising a base plate having a cylindrical shape and a plurality of protrusions projecting radially from a plurality of circumferential locations on the base plate.

[0019] In this case, each of the plurality of protrusions may have a pair of inclined surfaces at both ends on the axial side, which are inclined so that they move further apart in the axial direction as they approach the substrate portion in the radial direction.

[0020] In a reverse input blocking clutch according to one aspect of the present disclosure, the limiting member can be fitted onto the movable element.

[0021] Alternatively, the limiting member can be fitted inside the fixing element.

[0022] In a reverse input blocking clutch according to one aspect of the present disclosure, the movable element may have a first inner diameter side circumferential surface portion on its outer circumferential surface where the limiting member is arranged around it, a second inner diameter side circumferential surface portion on the outer circumferential surface portion located on one axial side of the first inner diameter side circumferential surface portion, and a third inner diameter side circumferential surface portion on the outer circumferential surface portion located on the other axial side of the first inner diameter side circumferential surface portion. In this case, the radial distance between the inner circumferential surface of the fixed element and the second inner diameter side circumferential surface portion can be made smaller than the radial distance between the inner circumferential surface of the fixed element and the first inner diameter side circumferential surface portion, and the radial distance between the inner circumferential surface of the fixed element and the third inner diameter side circumferential surface portion can be made smaller than the radial distance between the inner circumferential surface of the fixed element and the first inner diameter side circumferential surface portion.

[0023] In a reverse input blocking clutch according to one aspect of the present disclosure, the outer diameter of the second inner diameter side circumferential surface portion can be made larger than the outer diameter of the first inner diameter side circumferential surface portion, and the outer diameter of the third inner diameter side circumferential surface portion can be made larger than the outer diameter of the first inner diameter side circumferential surface portion.

[0024] Alternatively, the outer diameter of one of the second inner diameter side circumferential surface portion and the third inner diameter side circumferential surface portion can be made larger than the outer diameter of the first inner diameter side circumferential surface portion, and the outer diameter of the other of the second inner diameter side circumferential surface portion and the third inner diameter side circumferential surface portion can be made smaller than the outer diameter of the first inner diameter side circumferential surface portion.

[0025] In a reverse input blocking clutch according to one aspect of the present disclosure, the axial relative displacement of the movable element with respect to the fixed element can be limited.

[0026] In a reverse input blocking clutch according to one aspect of the present disclosure, the fixed element may have an axially oriented stepped surface and a locking groove on its inner circumferential surface. In this case, the movable element may be axially clamped between the stepped surface and a retaining ring locked in the locking groove.

[0027] According to one aspect of the present disclosure, a reverse input blocking clutch can prevent damage to the reverse input blocking clutch and / or the components constituting the mechanical device into which the reverse input blocking clutch is incorporated, even when an excessively large torque is reverse-inputted to the output member.

[0028] Figure 1 is an enlarged cross-sectional view of a main part showing an example of a mechanical device incorporating a reverse input blocking clutch of the first embodiment of the present disclosure. Figure 2 is an enlarged view of part I of Figure 1. Figure 3 is an enlarged view of part II of Figure 2. Figure 4 is a perspective view showing the reverse input blocking clutch of the first embodiment with the fixing element omitted. Figure 5 is a cross-sectional view showing the reverse input blocking clutch of the first embodiment with the fixing element omitted. Figure 6 is a cross-sectional view taken along line III-III of Figure 5. Figure 7 is a cross-sectional view taken along line III-III of Figure 5 showing the state in which rotational torque is input to the input member, with the biasing member omitted. Figure 8 is a cross-sectional view taken along line III-III of Figure 5 showing the state in which rotational torque is input to the output member, with the biasing member omitted. Figure 9 is a perspective view showing the limiting member removed from the reverse input blocking clutch of the first embodiment. Figure 10 is a diagram corresponding to Figure 5 for a second embodiment of the present disclosure. Figure 11 is a diagram corresponding to Figure 2 for a third embodiment of the present disclosure. Figure 12 is an enlarged view of section IV of Figure 11. Figure 13 is a perspective view of the third example of the reverse input blocking clutch, with the fixed elements omitted. Figure 14 is a cross-sectional view of the third example of the reverse input blocking clutch, with the fixed elements omitted. Figure 15 is a perspective view showing the limiting member removed from the third example of the reverse input blocking clutch.

[0029] [First Example] A first example of an embodiment of the present disclosure will be described with reference to Figures 1 to 9.

[0030] In the following description, unless otherwise specified, 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 member 3 side (the right side in Figures 1, 2, and 5), and the other axial side refers to the output member 4 side (the left side in Figures 1, 2, and 5).

[0031] The direction of the pressing surface 45 of the engaging element 5 relative to the pressed surface 6 is defined as the first direction (up and down direction in Figures 6 to 8), 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 6 to 8). For the engaging element 5, the direction coinciding with the first direction is defined as its radial direction (direction indicated by arrow α in Figure 6), and the direction coinciding with the second direction is defined as its width direction (direction indicated by arrow β in Figure 6).

[0032] <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.

[0033] Of the elements constituting the reverse input blocking clutch 1, the input member 3, output member 4, and engaging element 5 have the same configuration and function as a conventional reverse input blocking clutch.

[0034] The input member 3 has an input-side engaging portion 24 located radially inward of the pressed surface 6 provided on the inner circumferential surface of the pressed member 2, and is arranged coaxially with the pressed surface 6. The output member 4 has an output-side engaging portion 29 located radially inward of the input-side engaging portion 24, and is arranged coaxially with the pressed surface 6. The engaging element 5 has a pressing surface 45 facing the pressed surface 6, an input-side engaged portion 46 that can engage with the input-side engaging portion 24, and an output-side engaged portion 47 that can engage with the output-side engaging portion 29, and is arranged to be movable in the radial direction.

[0035] In the reverse input blocking clutch 1 of this disclosure, the engaging element 5 applies rotational torque T to the input member 3. ３When [input] is input, based on the engagement of the input-side engaging portion 24 with the input-side engaged portion 46, it moves in a direction away from the pressed surface 6 in the radial direction, and by engaging the output-side engaged portion 47 with the output-side engaging portion 29, the rotational torque T input to the input member 3 ３ is transmitted to the output member 4.

[0036] On the other hand, when the rotational torque T ４ is reversely input to the output member 4, based on the engagement of the output-side engaging portion 29 with the output-side engaged portion 47, the pressing surface 45 is pressed against the pressed surface 6, and the pressing surface 45 is frictionally engaged with the pressed surface 6. That is, basically, when the rotational torque T ４ is reversely input to the output member 4, the reverse input blocking clutch 1 blocks the rotation of the output member 4 and completely blocks the rotational torque T ４ reversely input to the output member 4.

[0037] In particular, in the reverse input blocking clutch 1 of the present disclosure, by improving the configuration of the pressed member 2, when the rotational torque T ４ reversely input to the output member 4 is less than or equal to a predetermined magnitude T ｔｈ (T ４ ≤ T ｔｈ ), the rotation of the output member 4 is blocked, but when the rotational torque T ４ reversely input to the output member 4 is greater than a predetermined magnitude T ｔｈ (T ４ > T ｔｈ ), it is configured to allow the rotation of the output member 4. Hereinafter, the components of the reverse input blocking clutch 1 will be described centered on the configuration of the pressed member 2 and the said feature.

[0038] (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 45 of the engaging element 5 when the engaging element 5 moves in a direction approaching the pressed surface 6. That is, the pressed surface 6 has a function of frictionally engaging with the pressing surface 45 of the engaging element 5 when the rotational torque T ４ is reversely input to the output member 4.

[0039] The input-side engaging portion 24 of the input member 3 and the output-side engaging portion 29 of the output member 4 are positioned radially inward of the pressed surface 6. On the radially inward side of the pressed surface 6, the input-side engaging portion 24, the output-side engaging portion 29, and the engaging element 5 are capable of rotation about the central axis O of the pressed surface 6.

[0040] The pressed surface 6 is annular when viewed from the axial direction. The shape of the pressed surface 6 in the axial direction is not limited to this, but in this example it is a cylindrical surface with no change in inner diameter in the axial direction.

[0041] In the reverse input blocking clutch 1, the pressed member 2 includes a fixed element 7 that does not rotate even when in use, a movable element 8 that has a pressed surface 6 and is arranged to allow relative rotation with respect to the fixed element 7, and a limiting member 9 arranged between the fixed element 7 and the movable element 8.

[0042] (Fixed element) The fixed element 7 does not rotate even when in use. The structure of the fixed element 7 can be such that it is supported and fixed to a fixed part that does not rotate even when in use, such as the housing 63, or the fixed element 7 is configured integrally with the fixed part as an element of the fixed part that does not rotate even when in use. In this example, the fixed element 7 is configured integrally with the housing 63 of the mechanical device 58.

[0043] Since the limiting member 9 is positioned between the fixed element 7 and the movable element 8, the movable element 8 and the limiting member 9 are positioned radially inward from the inner circumferential surface of the fixed element 7, or they are positioned on one or the other axial side of the fixed element 7. Therefore, the fixed element 7 has a surface on either its inner circumferential surface or its axial side that faces the outer circumferential surface or axial side of the movable element 8. These surfaces are basically composed of cylindrical or flat surfaces and can be equipped with a structure to limit the relative displacement of the movable element 8 and / or the limiting member 9 with respect to the fixed element 7.

[0044] In this example, the movable element 8 and the limiting member 9 are arranged radially inward on the inner surface of the fixed element 7, and the movable element 8 is restricted from axial relative displacement with respect to the fixed element 7. For this purpose, the fixed element 7 has an axially oriented stepped surface 10 and a locking groove 11 on its inner surface. The stepped surface 10 and the locking groove 11 are provided to axially clamp the movable element 8 between the stepped surface 10 and the retaining ring 12 locked in the locking groove 11, thereby restricting its axial relative displacement.

[0045] Furthermore, the fixing element 7 has a cylindrical surface portion 13 in the axial middle of its inner circumferential surface, except for a relief portion provided at the connection point with the stepped surface 10, in which the inner diameter does not change along the axial direction, and a small-diameter surface portion 14 having an inner diameter smaller than the inner diameter of the cylindrical surface portion 13 at the other end of the inner circumferential surface. The stepped surface 10 is provided at the portion connecting the cylindrical surface portion 13 and the small-diameter surface portion 14, and is composed of a flat surface perpendicular to the central axis of the cylindrical surface portion 13 and facing one side in the axial direction. The locking groove 11 is provided around the entire circumference of the inner circumferential surface of the fixing element 7 in the portion adjacent to the one side in the axial direction of the cylindrical surface portion 13.

[0046] (Movable element) The movable element 8 is positioned radially inward of the fixed element 7, and is capable of relative rotation with respect to the fixed element 7. The movable element 8 has a pressed surface 6 in the axial direction portion of its inner circumferential surface where the engaging element 5 is positioned radially inward. Therefore, the inner circumferential surface of the movable element 8 constitutes the inner circumferential surface of the pressed member 2.

[0047] The movable element 8 is supported by a fixed part or fixed element 7, such as a housing 63, which does not rotate during use, so that it can rotate about the central axis of the pressed surface 6, that is, the rotational axis O of the input member 3 and the output member 4. This allows relative rotation of the movable element 8 with respect to the fixed element 7. It is preferable that the movable element 8 is positioned radially inward of the fixed element 7. In particular, it is more preferable that the movable element 8 is fitted inside the fixed element 7 radially. This is advantageous because it can reduce the axial dimension of the reverse input blocking clutch 1 and can appropriately restrict the radial position of the fixed element 7. In this example, the movable element 8 is positioned radially inward of the fixed element 7.

[0048] The structure in which the movable element 8 is arranged to allow relative rotation with respect to the fixed element 7 is arbitrary, but for example, by fitting the movable element 8 inside the radially inward side of the fixed element 7 via a limiting member 9, the output member 4 can be made to a predetermined size T ｔｈ When a torque greater than the specified value is input in reverse, the movable element 8 can be supported to rotate relative to the fixed element 7. In other words, by fitting the movable element 8 into the fixed element 7 via the limiting member 9, the rotational torque T input in reverse to the output member 4 can be supported. ４ is of a predetermined size T ｔｈ When it is not greater than this, the rotation relative to the fixed element 7 is blocked and the member is supported by the fixed element 7, but the rotational torque T is input in reverse to the output member 4. ４ is of a predetermined size T ｔｈ Rotation relative to the fixed element 7 is permitted only when it is greater than [a certain value].

[0049] The movable element 8 can also be supported by a fixed part that does not rotate during use, or by a fixed element 7, via a rolling bearing or the like.

[0050] The movable element 8 has a surface on either its outer circumferential surface or axial side facing the inner circumferential surface or axial side of the fixed element 7, in order to position the limiting member 9 between the fixed element 7 and the movable element 8. These surfaces are basically composed of cylindrical or flat surfaces, but they may be equipped with a structure to limit the relative displacement of the limiting member 9 with respect to the movable element 8.

[0051] In this example, the movable element 8 has a cylindrical portion 18 and a hollow circular plate-shaped side plate portion 19 extending radially inward from the other axial end of the cylindrical portion 18. In this example, the pressed surface 6 is formed by the inner circumferential surface of the cylindrical portion 18. Furthermore, in this example, the outer circumferential surface of the cylindrical portion 18 is fitted radially inward onto the inner circumferential surface of the fixed element 7 and has a structure for arranging the limiting member 9.

[0052] In this example, the inner circumferential surface of the side plate portion 19 is a bearing holding portion on which a radial rolling bearing 37a is installed to rotatably support one axial end of the output shaft portion 32 of the output member 4 with respect to the pressed member 2. The side plate portion 19 can be omitted if the input member 3 or the output member 4 is directly and rotatably supported by a fixed part such as the housing 63 or the fixing element 7 of the pressed member 2 via another member such as a radial rolling bearing.

[0053] The cylindrical portion 18 constituting the movable element 8 is fitted into the cylindrical surface portion 13 of the fixed element 7 by gap fitting. As a result, the movable element 8 is positioned radially inward of the fixed element 7, enabling relative rotation with respect to the fixed element 7.

[0054] The movable element 8 has a first inner diameter side circumferential surface portion 15 on its outer circumferential surface where a limiting member 9 is positioned between it and the inner circumferential surface of the fixed element 7, a second inner diameter side circumferential surface portion 16 on the outer circumferential surface portion located on one axial side of the first inner diameter side circumferential surface portion 15, and a third inner diameter side circumferential surface portion 17 on the outer circumferential surface portion located on the other axial side of the first inner diameter side circumferential surface portion 15.

[0055] The second inner diameter side circumferential surface portion 16 and the third inner diameter side circumferential surface portion 17 are optional and additional structures, but they have the function of stabilizing the radial position of the movable element 8 relative to the fixed element 7 by reducing the distance between the portion of the outer circumferential surface of the movable element 8 where the limiting member 9 is not placed and the inner circumferential surface of the fixed element 7, to the extent that the rotation of the movable element 8 is not hindered.

[0056] The radial distance d between the inner circumferential surface of the fixing element 7 and the second inner diameter side circumferential surface portion 16. ２ This is the radial distance d between the inner circumferential surface of the fixed element 7 and the first inner diameter side circumferential surface portion 15. １ Smaller than (d ２ <d １ ), and the radial distance d between the inner circumferential surface of the fixing element 7 and the third inner diameter side circumferential surface portion 17. ３ This is the radial distance d between the inner circumferential surface of the fixed element 7 and the first inner diameter side circumferential surface portion 15. １ Smaller than (d ３ <d １As long as this relationship is satisfied, the relative sizes of the outer diameters of the first inner diameter side circumferential surface portion 15, the second inner diameter side circumferential surface portion 16, and the third inner diameter side circumferential surface portion 17 can be set arbitrarily.

[0057] For example, the outer diameter of the second inner diameter side circumferential surface portion 16 can be made larger than the outer diameter of the first inner diameter side circumferential surface portion 15, and the outer diameter of the third inner diameter side circumferential surface portion 17 can be made larger than the outer diameter of the first inner diameter side circumferential surface portion 15. In this case, the radial distance d between the inner circumferential surface of the fixed element 7 and the second inner diameter side circumferential surface portion 16. ２ The radial distance d between the inner circumferential surface of the fixed element 7 and the third inner diameter side circumferential surface portion 17. ３ These can be the same or different. Furthermore, the outer diameter of the second inner diameter side circumferential surface portion 16 and the outer diameter of the third inner diameter side circumferential surface portion 17 can be the same or different.

[0058] Alternatively, the outer diameter of one of the second inner diameter side circumferential surface portion 16 and the third inner diameter side circumferential surface portion 17 can be made larger than the outer diameter of the first inner diameter side circumferential surface portion 15, and the outer diameter of the other of the second inner diameter side circumferential surface portion 16 and the third inner diameter side circumferential surface portion 17 can be made smaller than the outer diameter of the first inner diameter side circumferential surface portion 15.

[0059] The radial distance d between the cylindrical surface portion 13 and the second inner diameter side circumferential surface portion 16 ２ , and the radial distance d between the cylindrical surface portion 13 and the third inner diameter side circumferential surface portion 17 ３ It is preferable to minimize the size of the movable element 8, as much as possible, without making the process of inserting the movable element 8 radially inward of the fixed element 7 excessively cumbersome.

[0060] In this example, the outer diameter of the second inner diameter side circumferential surface portion 16 is larger than the outer diameter of the first inner diameter side circumferential surface portion 15, and the outer diameter of the third inner diameter side circumferential surface portion 17 is larger than the outer diameter of the first inner diameter side circumferential surface portion 15. The radial distance d between the cylindrical surface portion 13 and the second inner diameter side circumferential surface portion 16. ２ The radial distance d between the cylindrical surface portion 13 and the first inner diameter side circumferential surface portion 15 is １ Smaller than (d ２ <d １ ), and the radial distance d between the cylindrical surface portion 13 and the third inner diameter side circumferential surface portion 17 ３ The radial distance d between the cylindrical surface portion 13 and the first inner diameter side circumferential surface portion 15 is１ It is smaller than (d ３ <d １ ).

[0061] With this configuration, even when a certain amount of radial distance is secured between the inner circumferential surface of the fixed element 7 and the first inner diameter side circumferential surface portion 15 in order to install the limiting member 9, it is possible to prevent the radial displacement and / or inclination of the central axis of the movable element 8 with respect to the central axis of the fixed element 7 from becoming excessively large. Therefore, even if the central axis of the output member 4 supported by the side plate portion 19 is inclined with respect to the central axis of the input member 3, it is possible to prevent this inclination from becoming excessive. As a result, the radial position of the movable element 8 with respect to the fixed element 7 can be appropriately controlled, and the function of allowing the rotation of the output member 4 when an excessive torque is input in reverse to the output member 4 can be performed stably and appropriately.

[0062] Furthermore, in this example, the outer diameter of the second inner diameter side circumferential surface portion 16 and the outer diameter of the third inner diameter side circumferential surface portion 17 are the same. Therefore, the radial distance d between the cylindrical surface portion 13 and the second inner diameter side circumferential surface portion 16 is ２ The radial distance d between the cylindrical surface portion 13 and the third inner diameter side circumferential surface portion 17. ３ These are the same as each other.

[0063] In this example, the cylindrical portion 18 has a recess 20 with a rectangular cross-sectional shape in the axial middle portion of its outer circumferential surface. In this example, the first inner diameter side circumferential surface portion 15 is formed by the bottom surface of the recess 20. Therefore, the axial displacement of the limiting member 9 fitted onto the first inner diameter side circumferential surface portion 15 relative to the movable element 8 can be restricted.

[0064] The second inner diameter side circumferential surface portion 16 is provided on the outer circumferential surface of the cylindrical portion 18 in a portion adjacent to one side of the recess 20 in the axial direction, and the third inner diameter side circumferential surface portion 17 is provided on the outer circumferential surface of the cylindrical portion 18 in a portion adjacent to the other side of the recess 20 in the axial direction.

[0065] The cylindrical portion 18 is axially clamped between the stepped surface 10 of the fixed element 7 and the retaining ring 12 which is locked in the locking groove 11. The axial distance between the stepped surface 10 and the retaining ring 12 is slightly larger than the axial dimension of the cylindrical portion 18. Therefore, the movable element 8 is allowed to rotate relative to the fixed element 7 when an excessive torque is input to the output member 4, while its relative axial displacement relative to the fixed element 7 is limited, preferably substantially impossible.

[0066] (Restricting Member) The restricting member 9 is positioned between the fixed element 7 and the movable element 8. The restricting member 9 is positioned against the rotational torque T that is input in reverse to the output member 4. ４ However, the torque has a predetermined magnitude T ｔｈ The following is (T ４ ≦T ｔｈ In this case, relative rotation of the movable element 8 with respect to the fixed element 7 is prevented, while the rotational torque T input in reverse to the output member 4 is prevented. ４ is of a predetermined size T ｔｈ Larger than (T ４ >T ｔｈ In this case, it has the function of allowing relative rotation of the movable element 8 with respect to the fixed element 7.

[0067] In other words, the rotational torque T is input in reverse to the output member 4. ４ is of a predetermined size T ｔｈ In the following cases, the limiting member 9 prevents the rotation of the movable element 8 with respect to the fixed element 7, thereby preventing the rotation of the output member 4. In contrast, the rotational torque T input in reverse to the output member 4 is prevented. ４ is of a predetermined size T ｔｈ If the value is greater than this, the limiting member 9 allows the rotation of the output member 4 by allowing the relative rotation of the movable element 8 with respect to the fixed element 7.

[0068] The manner in which the limiting member 9 is positioned between the fixed element 7 and the movable element 8 is arbitrary as long as the above-mentioned function of the limiting member 9 can be realized. The limiting member 9 can be positioned between the inner circumferential surface of the fixed element 7 and the outer circumferential surface of the movable element 8, i.e., sandwiched in the radial direction, or it can be positioned between the axial side surface of the fixed element 7 and the axial side surface of the movable element 8, i.e., sandwiched in the axial direction.

[0069] The limiting member 9 can be composed of a tolerance ring, a collar or spacer made of an elastomer such as rubber or a synthetic resin, a torque limiter, or other components necessary to achieve its function.

[0070] Tolerance rings are formed by pressing and bending elastic metal plates, including spring steel such as carbon steel and stainless steel.

[0071] The tolerance ring may be either a shaft variable (SV) type, in which multiple protrusions 22 project radially outward from multiple locations in the circumferential direction of the base plate portion 21, or a housing variable (HV) type, in which multiple protrusions project radially inward from multiple locations in the circumferential direction of the base plate portion. When a shaft variable (SV) type tolerance ring is used as the limiting member 9, the limiting member 9 is fitted onto the movable element 8. When a housing variable (HV) type tolerance ring is used as the limiting member 9, the limiting member 9 is fitted onto the fixed element 7.

[0072] A torque limiter is a type of coupling that transmits torque between components within a set torque range, and cuts off the transmission of torque between components by slipping when the set torque is exceeded.

[0073] When a tolerance ring or torque limiter is applied as the limiting member 9, the limiting member 9 is placed between the fixed element 7 and the movable element 8, and by adjusting its function, the threshold value for whether or not to allow relative rotation of the movable element 8 with respect to the fixed element 7 is set to a predetermined magnitude T related to torque. ｔｈ By setting it in this way, it is possible to realize the function of the limiting member 9.

[0074] When a collar or spacer is used as the limiting member 9, a metal, elastomer such as rubber, or synthetic resin member can be used. The collar or spacer is frictionally engaged with both the fixed element 7 and the movable element 8 by adjusting the surface properties of both the surface that engages with the fixed element 7 and the surface that engages with the movable element 8. By adjusting the surface properties of these members, a threshold value T of torque is set that allows relative rotation of the movable element 8 with respect to the fixed element 7. ｔｈ By setting it to this, it becomes possible to realize the function of the limiting member 9.

[0075] A predetermined magnitude T of torque is the threshold value for determining whether or not to allow relative rotation of the movable element 8 with respect to the fixed element 7. ｔｈ This can be adjusted by changing the specifications of the limiting member 9. In any case, the limiting member 9 controls the rotational torque T that is input in reverse to the output member 4. ４ is of a predetermined size T ｔｈ The following is (T ４ ≦T ｔｈ In this case, relative rotation of the movable element 8 with respect to the fixed element 7 is prevented, while the rotational torque T input in reverse to the output member 4 is prevented. ４ is of a predetermined size T ｔｈ Larger than (T ４ >T ｔｈ In this case, the performance is adjusted to allow relative rotation of the movable element 8 with respect to the fixed element 7. With this configuration, the rotational torque T that is input in reverse to the output member 4 relative to the fixed element 7 is adjusted. ４ The ability to switch the rotation of the movable element 8 according to its size is available.

[0076] In this example, the limiting member 9 is made up of a tolerance ring comprising a base portion 21 having a notched cylindrical shape and a plurality of protrusions 22 projecting radially from multiple locations in the circumferential direction of the base portion 21, and is sandwiched radially between the cylindrical surface portion 13 of the fixed element 7 and the first inner diameter side circumferential surface portion 15 of the movable element 8. In other words, the limiting member 9 is radially braced between the cylindrical surface portion 13 and the first inner diameter side circumferential surface portion 15.

[0077] In this example, the limiting member 9 is composed of a shaft variable (SV) type tolerance ring. Therefore, the base portion 21 is elastically fitted onto the first inner diameter side circumferential surface portion 15 of the movable element 8, and the tips of the multiple protrusions 22 are pressed against the cylindrical surface portion 13 of the fixed element 7.

[0078] Each of the multiple protrusions 22 has a pair of inclined surfaces 23 at both ends in the axial direction, which are inclined so that they move further apart in the axial direction as they approach the base plate portion 21 in the radial direction. The pair of inclined surfaces 23 have the function of facilitating the insertion work when moving and installing the limiting member 9 in the axial direction.

[0079] A predetermined size T ｔｈ It is set to an appropriate size so as to prevent damage to the reverse input blocking clutch 1 and / or the components constituting the mechanical device 58 in which the reverse input blocking clutch 1 is incorporated. For example, a predetermined size T ｔｈ This is not limited to, but includes the rotational torque T input from the electric motor 59 to the input member 3. ３ It can be made to be about two to four times the maximum value.

[0080] In this example, by changing the number of protrusions 22, their radial thickness, axial length, and / or circumferential width, a predetermined size T can be achieved. ｔｈ It is being adjusted to the appropriate size.

[0081] In the assembly process of the reverse input blocking clutch 1 in this example, the assembly of the pressed member 2 can be performed by first elastically fitting the limiting member 9 onto the first inner diameter side circumferential surface portion 15 of the movable element 8, then inserting the movable element 8 radially inward of the fixed element 7, and finally locking the retaining ring 12 into the locking groove 11.

[0082] In this example, since a pair of inclined surfaces 23 are provided at both ends of the projection 22 in the axial direction, when inserting the movable element 8, to which the limiting member 9 is fitted, into the radially inward side of the fixed element 7, it is possible to prevent the axial ends of the projection 22 from catching on the inner circumferential surface of the fixed element 7, thereby making the insertion work easier.

[0083] The assembly of components other than the pressed member 2 can be carried out in any procedure, as long as it does not create inconsistencies. For example, first, as shown in Figure 4, the components other than the fixed element 7 can be assembled, and then the movable element 8 can be inserted radially inward of the fixed element 7, and the retaining ring 12 can be locked into the locking groove 11.

[0084] In the reverse input blocking clutch 1, the pressed member 2 is configured to include a fixed element 7, a movable element 8, and a limiting member 9, thereby blocking the rotational torque T that is reverse input to the output member 4. ４ is of a predetermined size T ｔｈ The following is (T ４ ≦T ｔｈ In this case, the frictional force acting between the fixed element 7, the movable element 8 and the limiting member 9 prevents the relative rotation of the movable element 8 with respect to the fixed element 7. As a result, the rotation of the output member 4 is locked, and the rotational torque T that is input in reverse to the output member 4 is blocked. ４ The signal is completely blocked and not transmitted to the input member 3.

[0085] In contrast, the rotational torque T is input in reverse to the output member 4. ４ is of a predetermined size T ｔｈ Larger than (T ４ >T ｔｈ In this case, slippage occurs between the fixed element 7 and the limiting member 9, and / or between the movable element 8 and the limiting member 9, allowing relative rotation of the movable element 8 with respect to the fixed element 7. This allows rotation of the output member 4. At this time, the rotational torque T input in reverse to the output member 4 ４ A portion of it is transmitted to the input member 3, and the rest is blocked.

[0086] With this configuration, if an excessively large torque is reverse-inputted to the output member 4, the rotation of the output member 4 is permitted, preventing damage to the reverse input blocking clutch 1 and / or the components constituting the mechanical device 58 into which the reverse input blocking clutch 1 is incorporated.

[0087] (Input Member) The input member 3 has an input-side engaging portion 24 located radially inward of the pressed surface 6 and is arranged coaxially with the pressed surface 6.

[0088] The input member 3 is connected to an input-side mechanism such as an electric motor 59, and the rotational torque T ３ The input is received. Specifically, the input member 3 is composed of the output shaft of the input-side mechanism, or it is composed as a separate member from the output shaft, etc., and can be fixed coaxially to the output shaft, etc. In this example, the input member 3 is fixed coaxially to the motor output shaft 62 of the electric motor 59.

[0089] The input-side engaging portion 24 is provided on a part of the input member 3 that is radially outward from the rotational axis O, and has a portion that engages with the input-side engaged portion 46 of the engaging element 5. The input-side engaging portion 24 is configured to engage (contact) its radially inner surface 25 with the radially inner surface of the input-side engaged portion 46 as the input member 3 or engaging element 5 rotates.

[0090] In this example, the input member 3 has an input shaft portion 26 and an input flange portion 27, in addition to the input-side engaging portion 24.

[0091] The input shaft portion 26 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 26 has a cylindrical shape. In this example, the input member 3 is connected and fixed to the motor output shaft 62 in a manner that enables torque transmission by press-fitting and fixing the inner circumferential surface of the input shaft portion 26 to the outer circumferential surface of the motor output shaft 62. However, the input shaft portion 26 and the motor output shaft 62 can be connected not only by press-fitting and fixing, but also by non-circular engagements such as spline engagements, as long as torque can be transmitted between them.

[0092] The input flange portion 27 is an element for positioning the input-side engaging portion 24 at a location radially outward from the rotation center of the input member 3. In this example, it protrudes radially outward from the outer circumferential surface of the other axial end of the input shaft portion 26 over its entire circumference.

[0093] The input-side engaging portion 24 protrudes axially toward the other side from the portion of the input flange portion 27 that is radially outward from the center of rotation on the other axial side.

[0094] The input-side engaging portion 24 is an element that, when rotational torque is applied to the input member 3, engages with the input-side engaged portion 46 of the engaging element 5, causing the engaging element 5 to rotate in the same direction as the input torque. The shape of the input-side engaging portion 24 is not limited as long as it is configured to engage with the input-side engaged portion 46 of the engaging element 5.

[0095] For example, the input-side engaging portion 24 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 24 has an end face shape that is symmetrical with respect to the circumferential direction.

[0096] For example, the input-side engaging portion 24 may have a partially annular shape, a substantially trapezoidal shape, or a similar end face shape, where the circumferential width increases as it extends radially outward when viewed from the axial direction. In this example, the circumferential middle portion of the radially inner surface 25 of the input-side engaging portion 24 is composed 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 24 when viewed from the axial direction, while the circumferential side portions are composed of partially cylindrical convex surfaces that are inclined radially outward as they extend circumferentially to both sides. The radially outer surface 28 of the input-side engaging portion 24 is composed of a partially cylindrical convex surface centered on the central axis O.

[0097] The number of input-side engaging portions 24 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 24 are also composed of multiple input-side engaging portions 24. In this example, the engaging element 5 is composed of two engaging elements 5. Therefore, the input-side engaging portions 24 are composed of two input-side engaging portions 24, in accordance with the number of engaging elements 5. The two input-side engaging portions 24 are positioned at two radially opposite locations on the other axial side of the input flange portion 27, and are spaced apart from each other with respect to the radial direction of the input member 3.

[0098] The input member 3 is rotatably supported by the fixed portion or 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 61 which is coupled and fixed to a housing 63 via a motor output shaft 62.

[0099] (Output Member) The output member 4 has an output-side engaging portion 29 that is located radially inward from the input-side engaging portion 24, 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.

[0100] The output member 4 is connected to an output-side mechanism such as a gearbox, and is configured to output rotational torque to the output-side mechanism as it rotates. Specifically, the output member 4 can be made up of the input section of the output-side mechanism, or it can be made up as a separate component from the input section and fixed coaxially to the input section. In this example, the output member 4 is fixed coaxially to the drive pulley 69, which is the input section of the gearbox 68.

[0101] The output-side engaging portion 29 has a portion that engages with the output-side engaged portion 47 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 47 of the engaging element 5 and rotates the engaging element 5 in the same direction as the reverse input torque.

[0102] The portion of the output-side engaging portion 29 that engages with the output-side engaged portion 47 of the engaging element 5 is located radially inward from the input-side engaging portion 24 and radially outward from the rotational axis O of the output member 4, and is positioned to engage with the output-side engaged portion 47 of the engaging element 5. The output-side engaging portion 29 is configured to engage (contact) its outer circumferential surface with the output-side engaged portion 47 as the output member 4 or engaging element 5 rotates.

[0103] The output-side engaging portion 29 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 29, which is the part that engages with the output-side engaged portion 47, is not constant in the circumferential direction.

[0104] The number of parts of the output-side engaging portion 29 that engage with the output-side engaged portion 47 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 29 is also configured to have multiple engaging parts. In this example, the output-side engaging portion 29 is configured to have two parts that engage with the output-side engaged portion 47, corresponding to the number of engaging elements 5. However, even when there is only one engaging element 5, it is possible to adopt a structure similar to this example.

[0105] When the output-side engaging portion 29 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 29 is arbitrary as long as the output-side engaging portion 29 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.

[0106] In this example, the output-side engaging portion 29 has a substantially rectangular cross-sectional shape, as shown in Figure 6, 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 29 is composed of two parallel flat surfaces 30 and two convex curved surfaces 31, each partially cylindrical in shape.

[0107] In this example, the output-side engaging portion 29 is symmetric 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 30. Furthermore, the output-side engaging portion 29 is symmetric 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 30. That is, the output-side engaging portion 29 has a shape that is twice symmetric with respect to the central axis of the output member 4. The output-side engaging portion 29 is located radially inside the two input-side engaging portions 24 and is positioned between the output-side engaged portions 47 of the two engaging elements 5.

[0108] In this example, the output member 4 has an output-side engaging portion 29, as well as an output shaft portion 32 and a small-diameter shaft portion 33.

[0109] The output shaft portion 32 is an element for connecting the output member 4 and the input portion of the output mechanism so as to be able to transmit rotational torque. In this example, the output shaft portion 32 has a stepped cylindrical shape. Specifically, the output shaft portion 32 has a large diameter portion 34, a medium diameter portion 35, and a small diameter portion 36 in order from one side in the axial direction. In this example, the drive pulley 69 of the reduction gear 68 is externally fitted and fixed to the medium diameter portion 35.

[0110] The output-side engaging portion 29 protrudes from the center of the end face on one axial side of the output shaft portion 32 toward the axial side.

[0111] The small-diameter shaft portion 33 has a cylindrical shape and protrudes in the axial direction from the center of the end face on one axial side of the output-side engaging portion 29.

[0112] 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.

[0113] (Support Member) The reverse input blocking clutch 1 in this example is equipped with a support member 38 to rotatably support the other axial end (small diameter portion 36) of the output shaft portion 32 with respect to the movable element 8 by a radial rolling bearing 37b on the other axial side.

[0114] The support member 38 comprises a cylindrical bearing holder 39, a partial cylindrical portion 40 extending axially from a single circumferential position at one end of the bearing holder 39 on one axial side, and an outward flange portion 41 extending radially outward from one end of the partial cylindrical portion 40 on one axial side.

[0115] The support member 38 is supported and fixed to the movable element 8 by screwing a bolt 43, which is inserted through a through hole 42 provided in the outward flange portion 41, into a screw hole 44 provided in the side plate portion 19 of the movable element 8.

[0116] The other axial end (small diameter portion 36) of the output shaft portion 32 is rotatably supported by a radial rolling bearing 37b on the other axial side with respect to the inner circumferential surface of the bearing holding portion 39 of the support member 38.

[0117] In the illustrated example, the radial rolling bearings 37a and 37b are each ball bearings using balls as rolling elements. However, the radial rolling bearings supporting the output member 4 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 37a and 37b.

[0118] (Engaging element) The engaging element 5 has a pressing surface 45 facing the pressed surface 6, an input-side engaged portion 46 that can engage with the input-side engaging portion 24, and an output-side engaged portion 47 that can engage with the output-side engaging portion 29, and is arranged to allow movement of the engaging element 5 in the radial direction (first direction).

[0119] The engaging element 5 applies rotational torque T to the input member 3. ３ When input is received, the input-side engaging portion 24 engages with the input-side engaged portion 46, and moves radially away from the pressed surface 6, causing the output-side engaged portion 47 to engage with the output-side engaging portion 29, thereby transmitting the rotational torque input to the input member 3 to the output member 4, while the output member 4 receives the rotational torque T ４ When reverse input is applied, the output-side engaging portion 29 engages with the output-side engaging portion 47, and the pressing surface 45 is pressed against the pressed surface 6, causing the pressing surface 45 to frictionally engage with the pressed surface 6.

[0120] The pressing surface 45 is provided on the radially outer surface of the engaging element 5 that faces the pressed surface 6. The shape and size of the pressing surface 45 are arbitrary as long as they can frictionally engage with the pressed surface 6. The pressing surface 45 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 45 can be provided for one engaging element 5, or multiple pressing surfaces 45 can be provided. The radius of curvature of the pressing surface 45 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.

[0121] In this example, the pressing surface 45 is composed of two pressing surfaces 45 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 45 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.

[0122] Of the radially outer surface of the engaging element 5, the portion that is circumferentially away from the two pressing surfaces 45 is located radially inward from a virtual circle that is centered on the central axis O of the input member 3 and tangent to the two pressing surfaces 45, when viewed from the axial direction. In other words, when the two pressing surfaces 45 are in contact with the surface to be pressed 6, the portion that is circumferentially away from the two pressing surfaces 45 does not come into contact with the surface to be pressed 6.

[0123] The pressing surface 45 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 45 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 bonding.

[0124] In this example, the input-side engaged portion 46 is provided in the radially intermediate portion of the widthwise center of the engaging element 5. More specifically, although not limited to this, the input-side engaged portion 46 has a substantially arc-shaped opening when viewed from the axial direction and 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.

[0125] The input-side engaged portion 46 is sized to allow the input-side engaged portion 24 to be loosely inserted. Therefore, when the input-side engaged portion 24 is inserted inside the input-side engaged portion 46, there are gaps between the input-side engaged portion 24 and the inner surface of the input-side engaged portion 46 in the width direction and the radial direction of the engaging element 5. As a result, the input-side engaged portion 24 can be displaced relative to the input-side engaged portion 46 in the rotational direction of the input member 3, and the input-side engaged portion 46 can be displaced radially relative to the input-side engaged portion 24.

[0126] The input-side engaged portion 46 engages with the input-side engaged portion 24 as the input member 3 rotates, and is an element that receives the rotational torque input from the input member 3. The input-side engaged portion 46 is not limited in its shape or structure, as long as it is configured to engage with the input-side engaged portion 24.

[0127] In this example, the radially inner surface 48 of the inner surface of the input-side engaged portion 46, which faces radially outward, is made up of a flat surface perpendicular to the first direction, and the radially outer surface 49 of the inner surface of the input-side engaged portion 46, which faces radially inward, is made up 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 50 connecting the ends on both sides of the radially inner surface 48 in the second direction and the ends on both sides of the radially outer surface 49 in the second direction is made up of a partially cylindrical concave curved surface.

[0128] The output-side engaged portion 47 engages with the output-side engaged portion 29 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. In this example, the output-side engaged portion 47 is provided at the center in the width direction of the radially inner surface of the engaging element 5.

[0129] In this example, the engaging element 5 has a flat surface portion 51 on its radially inner surface that is perpendicular to the radial direction of the engaging element 5, and has two protrusions 52 projecting radially inward at two positions on the flat surface portion 51 in the width direction of the engaging element 5. The output-side engaged portion 47 is composed of the portion of the flat surface portion 51 that is located between the two protrusions 52 in the width direction. In this example, the width dimension of the output-side engaged portion 47, i.e., the distance between the two protrusions 52, is larger than the width dimension of the flat surface 30 of the output-side engaging portion 29.

[0130] In the reverse input blocking clutch 1 of this example, the pressing surfaces 45 of the two engaging elements 5 are oriented radially toward opposite sides of each other, and their flat surfaces 51 are facing each other. Each engaging element 5 is positioned radially inward of the movable element 8, and is capable of moving in a first direction, which is the radial direction of each engaging element 5 and corresponds to the direction of proximity of the pressing surface 45 to the pressed surface 6. Furthermore, the two input-side engaging portions 24 of the input member 3, positioned on one axial side, are inserted axially into the respective input-side engaged portions 46 of the two engaging elements 5, and the output-side engaging portion 29 of the output member 4, positioned on the other axial side, is inserted axially between the output-side engaged portions 47 of the two engaging elements 5. In other words, the two engaging elements 5 are positioned so that their respective output-side engaged portions 47 sandwich the output-side engaging portion 29 from the radial outside.

[0131] With the two engaging elements 5 positioned radially inward of the movable element 8, the inner diameter of the movable element 8 and the radial dimensions of the engaging elements 5 are restricted so that a gap exists in at least one of the following locations: between the pressed surface 6 and the two pressing surfaces 45, and between the tip surfaces of the two combinations of protrusions 52 formed by the two protrusions 52 of the two engaging elements 5 facing each other.

[0132] (Biasing Member) The reverse input blocking clutch 1 in this example further comprises a biasing member 53 as an optional component.

[0133] The biasing member 53 elastically biases the engaging element 5 toward the pressed surface 6. The biasing member 53 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 53 is not particularly limited and is appropriately determined according to the number of engaging elements 5.

[0134] In this example, the biasing member 53 is composed of two biasing members 53 positioned at two locations in the width direction between the radially inner surfaces of the two engaging elements 5, and each biasing member 53 is composed of a compression coil spring. A protrusion 52 is inserted into the inside of both ends in the extension direction of each biasing member 53. This prevents each biasing member 53 from falling out of the space between the two engaging elements 5.

[0135] The two biasing members 53 elastically bias the two engaging elements 5 toward the pressed surface 6 by the force that attempts to restore their elasticity. 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 45 of the two engaging elements 5 come into contact with the pressed surface 6.

[0136] (Spacer and stopper member) The reverse input blocking clutch 1 in this example also further comprises two spacers 54 and a stopper member 55 as optional components.

[0137] Each spacer 54 has the function of restricting the axial position of the engaging element 5 with respect to the output member 4.

[0138] In this example, each spacer 54 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 54 has a through hole 56 through which the output-side engaging portion 29 can be inserted without rattling. Each spacer 54 is positioned on both axial sides of the two engaging elements 5 with the output-side engaging portion 29 inserted through the through hole 56 without rattling.

[0139] The stopper member 55 has the function of preventing one of the two spacers 54, the axial spacer 54, from moving axially to the axial side and falling off the output member 4.

[0140] In this example, the stopper member 55 is made up of a segmented annular retaining ring. The stopper member 55 is locked to a small-diameter shaft portion 33 provided at the other axial end of the output member 4.

[0141] <Explanation of the operation of the reverse input blocking clutch> The operation of the reverse input blocking clutch 1 in this example will be explained using Figures 7 and 8. Note that Figures 7 and 8 omit the biasing member 53 and exaggerate the radial gap between the input member 3 and the output member 4 and the two engaging elements 5.

[0142] (When rotational torque is applied to the input member) Rotational torque T is applied to the input member 3 ３When input is received, 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 7, the input-side engaging portion 24 rotates inside the input-side engaged portion 46 in the rotation direction of the input member 3 (counterclockwise in the example of Figure 7).

[0143] This reduces the gap between the radially inner surface 25 of the input-side engaging portion 24 and the radially inner surface 48 of the input-side engaged portion 46, causing the radially inner surface 25 of the input-side engaging portion 24 to come into contact with the radially inner surface 48 of the input-side engaged portion 46.

[0144] From this state, as the input member 3 rotates further, the radially inner surface 48 of the input side engaged portion 46 is pressed radially inward by the radially inner surface 25 of the input side engaged portion 24, and the engaging element 5 moves away from the pressed surface 6. That is, the two engaging elements 5 move radially inward, which is the direction in which they move closer to each other, based on their engagement with the input member 3, and the radially inner surfaces of the two engaging elements 5 approach each other, and the output side engaged portion 29 of the output member 4 is clamped from both radial sides by the output side engaged portions 47 of the two engaging elements 5.

[0145] In this way, the output member 4 is rotated so that the flat surface 30 of the output-side engaging portion 29 is parallel to the flat surface portion 51 of the engaging element 5, while the output-side engaging portion 29 and the output-side engaged portion 47 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.

[0146] (When rotational torque is input in reverse to the output member) Rotational torque T is applied to the output member 4 ４ When reverse input is applied, 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 8, the output-side engaging portion 29 rotates in the direction of rotation of the output member 4 (clockwise in the example of Figure 8) inside the output-side engaged portions 47 of the two engaging elements 5. The connection portion (corner) between the flat surface 30 and the convex curved surface 31 on the outer circumferential surface of the output-side engaging portion 29 presses the output-side engaged portion 47 radially outward, causing the two engaging elements 5 to move toward the pressed surface 6.

[0147] That is, based on the engagement with the output member 4, the two engaging elements 5 move toward the radially outer side, which is the direction in which they move away from each other, and the pressing surfaces 45 of the two engaging elements 5 come into contact with the pressed surface 6 and frictionally engage with the pressed surface 6.

[0148] In the reverse input blocking clutch 1 of this example, the size of the gap between each component member is adjusted so that the above operation is possible. In particular, in the positional relationship where the pressing surfaces 45 of the two engaging elements 5 are in contact with the pressed surface 6, a gap is provided between the radially inner surface 25 of the input-side engaging portion 24 and the radially inner surface 48 of the input-side engaged portion 46.

[0149] As a result, when the rotational torque T ４ is reversely input to the output member 4, the movement of the engaging element 5 toward the radially outer side is prevented from being blocked by the input-side engaging portion 24, and even after the pressing surface 45 comes into contact with the pressed surface 6, the surface pressure acting on the contact portion between the pressing surface 45 and the pressed surface 6 changes according to the magnitude of the rotational torque T ４ reversely input to the output member 4.

[0150] In the reverse input blocking clutch 1 of the present disclosure, when the rotational torque T ４ reversely input to the output member 4 is greater than a predetermined magnitude T ｔｈ (T ４ > T ｔｈ ), the rotation of the output member 4 is allowed by allowing the relative rotation of the movable element 8 with respect to the fixed element 7. For this reason, when an excessively large rotational torque T ４ is reversely input to the output member 4, it is possible to prevent damage to the reverse input blocking clutch 1 and / or the members constituting the mechanical device 58 in which the reverse input blocking clutch 1 is incorporated due to this torque. For example, when the mechanical device 58 is an electric jack, even when a heavy object drops on the load receiving portion and an impact load is applied to the load receiving portion, deformation of the components of the rotary-linear motion conversion device 60 and / or the speed reducer 68 existing between the load receiving portion and the reverse input blocking clutch 1 in the torque transmission path can be prevented.

[0151] Furthermore, in the reverse input blocking clutch 1 of this example, a first inner diameter side circumferential surface portion 15 is provided on the outer circumferential surface of the movable element 8 to secure space for the installation of the limiting member 9. However, a second inner diameter side circumferential surface portion 16 and a third inner diameter side circumferential surface portion 17 are provided on both sides of the axial direction to minimize the radial distance between the fixed element 7 and the movable element 8. This prevents the radial displacement and / or inclination of the central axis of the movable element 8 with respect to the central axis of the fixed element 7 from becoming excessively large.

[0152] For example, by placing a belt 71 over a drive pulley 69 fixed to the output member 4, the output member 4 is pulled by the tension of the belt 71, thereby preventing the central axis of the output member 4 from becoming excessively tilted relative to the central axis of the input member 3.

[0153] Therefore, even when the reverse input blocking clutch device 1 is incorporated into various mechanical devices, the radial position of the movable element 8 relative to the fixed element 7 can be appropriately controlled, thereby enabling the function of allowing the output member 4 to rotate when excessive torque is reverse-inputted to the output member 4 to be performed stably and appropriately.

[0154] The reverse input blocking clutch 1 can be incorporated into various mechanical devices. Examples of mechanical devices into which the reverse input blocking clutch 1 can be incorporated include rotating mechanical devices such as drive units that transmit the rotational motion of a drive source to a driven part as rotational motion, or mechanical devices such as electric jacks that convert the rotational motion of a drive source into linear motion and transmit it to a driven part. Below, an example in which the reverse input blocking clutch 1 of this example is incorporated into a mechanical device 58 that converts the rotational motion of a drive source into linear motion and transmits it to a driven part will be described.

[0155] The mechanical device 58 in this example includes, in addition to the reverse input blocking clutch 1, an electric motor 59 which is a drive source, and a rotary-to-linear motion converter 60. In the mechanical device 58, the output rotation of the electric motor 59 is input to the rotary-to-linear motion converter 60 via the reverse input blocking clutch 1, and the rotary-to-linear motion converter 60 converts it into linear motion.

[0156] The electric motor 59 comprises a motor housing 61, a motor output shaft 62 rotatably supported inside the motor housing 61, a rotor supported and fixed around the motor output shaft 62, and a stator arranged around the rotor and supported and fixed inside the motor housing 61.

[0157] The motor housing 61 is coupled and fixed to the fixing element 7.

[0158] The motor output shaft 62 is coupled and fixed to the input member 3 of the reverse input blocking clutch 1 so as to be able to transmit torque.

[0159] The rotary-to-linear motion converter 60 has the function of converting rotational motion input to the input unit into linear motion. The rotary-to-linear motion converter 60 can have any configuration as long as it has the above function.

[0160] For example, the rotary-to-linear motion converter 60 can be composed of a ball screw type or sliding screw type lead screw device, a cam device, etc. The rotary-to-linear motion converter 60 is preferably composed of a ball screw type lead screw device in order to ensure a sufficient stroke for linear motion and to ensure good efficiency. When a lead screw device is used as the rotary-to-linear motion converter 60, one of the screw shaft and the nut constitutes a rotational motion element that forms the input part to which rotational motion is input, and the other of the screw shaft and the nut constitutes a linear motion element.

[0161] In this example, the rotary-to-linear motion converter 60 is composed of a ball screw type feed screw device comprising a housing 63, a nut 64 which is an input section and a rotational motion element, a screw shaft 65 which is a linear motion element, and a plurality of balls (not shown).

[0162] The nut 64 has a helical female ball screw groove on its inner circumferential surface. The nut 64 is supported inside the housing 63 by a bearing device 66, which allows it to rotate but prevents it from moving in the axial direction.

[0163] The screw shaft 65 has a helical male ball screw groove 67 on its outer circumferential surface. The screw shaft 65 is inserted inside the nut 64 and is positioned coaxially with the nut 64. The screw shaft 65 is supported inside the housing 63 so as to be unable to rotate but able to move in the axial direction. The screw shaft 65 also has a driven part (not shown).

[0164] Multiple balls are arranged to roll freely in a load path consisting of a female ball screw groove and a male ball screw groove 67.

[0165] The start and end points of the load path are connected by a circulation mechanism (not shown). Balls that reach the end point of the load path are returned to the start point of the load path via the circulation mechanism. The start and end points of the load path are swapped depending on the direction of relative axial movement (relative rotation direction) between the nut 64 and the screw shaft 65.

[0166] In the mechanical device 58, when the motor output shaft 62 is rotationally driven based on the energization of the stator of the electric motor 59, the nut 64 is rotationally driven via the reverse input blocking clutch 1. As the nut 64 rotates, multiple balls circulate through the circulation means and roll along the load path, causing the screw shaft 65 to move linearly in the axial direction, and the driven part provided on the screw shaft 65 to move linearly.

[0167] The nut 64, which is the input part of the rotary-to-linear motion converter 60, and the output member 4 of the reverse input blocking clutch 1 can be connected in a torque-transmission manner, either directly or via other members such as a coupling. Alternatively, the nut 64 and the output member 4 can be connected in a torque-transmission manner via a reduction gear 68, or a stepped or continuously variable transmission with an adjustable reduction ratio.

[0168] When the nut 64 and the output member 4 are connected via a reduction gear 68 to enable torque transmission, the type of reduction gear 68 is not particularly limited. For example, the reduction gear 68 can be a belt-type reduction gear, a chain-type reduction gear, a parallel gear type reduction gear, a worm gear reduction gear, a planetary gear type reduction gear, and the like.

[0169] In this example, the nut 64 and the output member 4 are connected in a torque-transmitting manner by a belt-type reduction gear 68. Specifically, the reduction gear 68 comprises a drive pulley 69 fitted and fixed to the output member 4, a driven pulley 70 fitted and fixed to the nut 64, and a belt 71 stretched between the drive pulley 69 and the driven pulley 70.

[0170] [Second Example] A second example of the embodiment of the present disclosure will be described with reference to Figure 10.

[0171] The reverse input blocking clutch in this example does not have the support member 38 that was provided in the reverse input blocking clutch 1 of the first example. In this example, one axial position of the output shaft portion 32a of the output member 4a is rotatably supported with respect to the movable element 8a by a single bearing device 72.

[0172] Specifically, the axial end (large diameter portion 34a) of the output shaft portion 32a is rotatably supported by a bearing device 72 with respect to the inner circumferential surface of an inner diameter cylindrical portion 73 that extends from the radially inner end of the side plate portion 19 of the movable element 8a toward the other axial direction.

[0173] In the illustrated example, the bearing device 72 is composed of back-to-back double-row angular contact ball bearings. However, the bearing device 72 can also be composed of face-to-face double-row angular contact ball bearings, double-row tapered roller bearings, double-row cylindrical roller bearings, etc.

[0174] The reverse input blocking clutch in this example can reduce the number of parts compared to the reverse input blocking clutch in the first example. Furthermore, since it does not have a support member 38, the belt 71 can be placed on the drive pulley 69 after the reverse input blocking clutch has been assembled to the machine device 58 (see Figure 1). This makes the assembly and maintenance work of the machine device 58 easier.

[0175] The other components and effects of the second example are the same as those of the first example.

[0176] [Third Example] A third example of the embodiment of the present disclosure will be described with reference to Figures 11 to 15.

[0177] In the reverse input blocking clutch 1a of this example, the limiting member 9a is made of a housing variable (HV) type tolerance ring in which a plurality of protrusions 22a protrude radially inward from multiple locations in the circumferential direction of the base plate portion 21. As a result, the base plate portion 21 is elastically fitted into the inner circumferential surface (large diameter surface portion 74) of the fixed element 7a, and the tips of the plurality of protrusions 22a are pressed against the outer circumferential surface (first inner diameter side circumferential surface portion 15a) of the movable element 8b.

[0178] Furthermore, the shape of the inner surface of the fixed element 7a and the shape of the outer surface of the movable element 8a have been changed from the structure of the first example.

[0179] The fixed element 7a has a large-diameter surface portion 74, a medium-diameter surface portion 75, and a small-diameter surface portion 76 in order from one side in the axial direction on the portion of its inner circumferential surface where the movable element 8a is positioned radially inward. The large-diameter surface portion 74 and the medium-diameter surface portion 75 are connected by a first stepped surface 77 facing one side in the axial direction, and the medium-diameter surface portion 75 and the small-diameter surface portion 76 are connected by a second stepped surface 78 facing one side in the axial direction. The limiting member 9a is fitted inside the large-diameter surface portion 74.

[0180] The movable element 8a (cylindrical portion 18a) has a stepped cylindrical outer surface. Specifically, the cylindrical portion 18a has, in order from one axial side, a second inner diameter side circumferential surface portion 16a, a first inner diameter side circumferential surface portion 15a, and a third inner diameter side circumferential surface portion 17a on its outer surface.

[0181] In this example, the outer diameter of the second inner diameter side circumferential surface portion 16a is larger than the outer diameter of the first inner diameter side circumferential surface portion 15a, and the outer diameter of the third inner diameter side circumferential surface portion 17a is smaller than the outer diameter of the first inner diameter side circumferential surface portion 15a. The first inner diameter side circumferential surface portion 15a and the third inner diameter side circumferential surface portion 17a are connected by an inner diameter side stepped surface 79 facing the other side in the axial direction.

[0182] With the movable element 8a positioned radially inward of the fixed element 7a, the second inner diameter side circumferential surface portion 16a and the first inner diameter side circumferential surface portion 15a face the large diameter surface portion 74, and the third inner diameter side circumferential surface portion 17a faces the medium diameter surface portion 75. In this state, the radial distance d between the large diameter surface portion 74 and the second inner diameter side circumferential surface portion 16a is ２ The radial distance d between the large diameter surface portion 74 and the first inner diameter side circumferential surface portion 15a is １smaller than (d ２ <d １ ), and the radial interval d ３ between the intermediate diameter face portion 75 and the third inner diameter side peripheral face portion 17a is smaller than the radial interval d １ between the large diameter face portion 74 and the first inner diameter side peripheral face portion 15a (d ３ <d １ ).

[0183] Further, the inner diameter side stepped face 79 faces the first stepped face 77, and the end face on the other axial side of the cylindrical portion 18a faces the second stepped face 78. The cylindrical portion 18a of the movable element 8a is axially sandwiched between the first stepped face 77 of the fixed element 7a or the second stepped face 78 and the retaining ring 12 locked to the locking groove 11. Thereby, relative axial displacement of the movable element 8a with respect to the fixed element 7a is substantially impossible.

[0184] In the assembly process of the reverse input blocking clutch 1a of this example, the assembly work of the pressed member 2a is first performed by elastically fitting the restricting member 9 into the large diameter face portion 74 of the fixed element 7a, then inserting the movable element 8a into the inner diameter side of the fixed element 7a from one axial side, and further locking the retaining ring 12 to the locking groove 11.

[0185] The configurations and operational effects of other parts of the third example are the same as those of the first and second examples.

[0186] 1, 1a Reverse input blocking clutch 2, 2a Pressed member 3 Input member 4, 4a Output member 5 Engaging element 6 Pressed surface 7, 7a Fixed element 8, 8a, 8b Movable element 9, 9a Restricting member 10 Stepped surface 11 Locking groove 12 Retaining ring 13 Cylindrical surface 14 Small diameter surface 15, 15a First inner diameter side circumferential surface 16, 16a Second inner diameter side circumferential surface 17, 17a Third inner diameter side circumferential surface 18 Cylindrical part 19 Side plate part 20 Recess 21 Base plate part 22, 22a Projection 23 Inclined surface 24 Input side engaging part 25 Radial inner surface 26 Input shaft part 27 Input flange part 28 Radial outer surface 29 Output side engaging part 30 Flat surface 31 Convex curved surface 32, 32a Output shaft section 33 Small diameter shaft section 34 Large diameter section 35 Medium diameter section 36 Small diameter section 37a, 37b Radial rolling bearing 38 Support member 39 Bearing holder section 40 Partial cylindrical section 41 Outward flange section 42 Through hole 43 Bolt 44 Screw hole 45 Pressing surface 46 Input side engaged section 47 Output side engaged section 48 Radial inner surface 49 Radial outer surface 50 Circumferential surface 51 Flat surface section 52 Convex section 53 Biasing member 54 Spacer 55 Stopper member 56 Through hole 58 Mechanical device 59 Electric motor 60 Rotary-to-linear motion converter 61 Motor housing 62 Motor output shaft 63 Housing 64 Nut 65 Screw shaft 66 Bearing device 67 Male ball screw groove 68 Reducer 69 Drive pulley 70 Driven pulley 71 Belt 72 Bearing device 73 Inner diameter cylindrical section 74 Large diameter surface section 75 Medium diameter surface section 76 Small diameter surface section 77 First stepped surface 78 Second stepped surface 79 Inner diameter stepped surface

Claims

1. A pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion located radially inward of the pressed surface and arranged coaxially with the pressed surface; an output member having an output-side engaging portion located radially inward of the input-side engaging portion 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 be movable in the radial direction. 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, thereby frictionally engaging the pressing surface with the pressed surface. The pressed member comprises: a fixed element that does not rotate even during use; a movable element having the pressed surface and arranged to allow relative rotation with respect to the fixed element; and a limiting member disposed between the fixed element and the movable element. The limiting member prevents relative rotation of the movable element with respect to the fixed element when the rotational torque reversed into the output member is less than or equal to a predetermined magnitude, while allowing relative rotation of the movable element with respect to the fixed element when the rotational torque reversed into the output member is greater than a predetermined magnitude, in a reverse input blocking clutch.

2. The reverse input blocking clutch according to claim 1, wherein the movable element is arranged radially inward of the fixed element.

3. The reverse input blocking clutch according to claim 2, wherein the limiting member is sandwiched radially between the inner circumferential surface of the fixed element and the outer circumferential surface of the movable element.

4. The reverse input blocking clutch according to claim 3, wherein the limiting member is composed of a tolerance ring comprising a base plate having a missing cylindrical shape and a plurality of protrusions projecting radially from a plurality of locations in the circumferential direction of the base plate.

5. The reverse input blocking clutch according to claim 4, wherein each of the plurality of protrusions has a pair of inclined surfaces at both ends on the axial side, which are inclined so that they move further apart from each other in the axial direction as they approach the substrate portion in the radial direction.

6. The reverse input blocking clutch according to claim 4, wherein the limiting member is fitted onto the movable element.

7. The reverse input blocking clutch according to claim 4, wherein the limiting member is fitted inside the fixing element.

8. The reverse input blocking clutch according to any one of claims 3 to 7, wherein the movable element has a first inner diameter side circumferential surface portion on its outer circumferential surface where the limiting member is arranged around it, a second inner diameter side circumferential surface portion on the outer circumferential surface portion located on one axial side of the outer circumferential surface portion than the first inner diameter side circumferential surface portion, and a third inner diameter side circumferential surface portion on the outer circumferential surface portion located on the other axial side of the outer circumferential surface portion than the first inner diameter side circumferential surface portion, the radial distance between the inner circumferential surface of the fixed element and the second inner diameter side circumferential surface portion is smaller than the radial distance between the inner circumferential surface of the fixed element and the first inner diameter side circumferential surface portion, and the radial distance between the inner circumferential surface of the fixed element and the third inner diameter side circumferential surface portion is smaller than the radial distance between the inner circumferential surface of the fixed element and the first inner diameter side circumferential surface portion.

9. The reverse input blocking clutch according to claim 8, wherein the outer diameter of the second inner diameter side circumferential surface portion is larger than the outer diameter of the first inner diameter side circumferential surface portion, and the outer diameter of the third inner diameter side circumferential surface portion is larger than the outer diameter of the first inner diameter side circumferential surface portion.

10. The reverse input blocking clutch according to claim 8, wherein the outer diameter of one of the second inner diameter side circumferential surface portion and the third inner diameter side circumferential surface portion is larger than the outer diameter of the first inner diameter side circumferential surface portion, and the outer diameter of the other of the second inner diameter side circumferential surface portion and the third inner diameter side circumferential surface portion is smaller than the outer diameter of the first inner diameter side circumferential surface portion.

11. The reverse input blocking clutch according to any one of claims 1 to 10, wherein the movable element is limited to its relative axial displacement with respect to the fixed element.

12. The reverse input blocking clutch according to claim 11, wherein the fixed element has an axially oriented stepped surface and a locking groove on its inner circumferential surface, and the movable element is axially sandwiched between the stepped surface and a retaining ring locked in the locking groove.

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