DE-112024002642-T5 - Coupling for blocking a reverse input and assembly method for it

DE112024002642T5DE 112024002642 T5DE112024002642 T5DE 112024002642T5DE-112024002642-T5

Abstract

[Problem] Providing a coupling structure to block a reverse input that can restrict movement in an axial direction of an engagement element relative to an output element, while reducing the number of parts. [Solution] The coupling for blocking a reverse input comprises a pressed link 2, an input link 3, an output link 4, an engagement element 5, and a retaining link 6. The retaining link 6 has a first spacer section 38, a second spacer section 39, and a connecting section 40 that connects the first spacer section 38 and the second spacer section 39, and restricts movement in the axial direction of the engagement element 5 relative to the output link 4 by being attached to the output link 4, with the engagement element 5 being positioned between the first spacer section 38 and the second spacer section 39 in the axial direction of the pressed surface 7.

Inventors

Kazuyuki HATANAKA

Assignees

NSK LTD.

Dates

Publication Date: 20260513
Application Date: 20240705
Priority Date: 20230720

Claims (20)

A coupling for blocking a reverse input, comprising: a pressed member having a pressed surface on an inner circumferential surface; an input member having an input-side engaging section located on an inner surface in a radial direction of the pressed surface and coaxial with the pressed surface; an output member having an output-side engaging section located further on the inner surface in the radial direction than the input-side engaging section and coaxial with the pressed surface; an engagement element comprising a pressing surface facing the pressed surface, an input-side engagement section that can be brought into engagement with the input-side engaging section, and an output-side engagement section that can be brought into engagement with the output-side engaging section, and arranged such that it is movable in a first direction, which is a direction in which the pressing surface moves toward or away from the pressed surface; and a retaining member comprising a first spacer section, a second spacer section, and a connecting section that connects the first spacer section and the second spacer section, and restricting axial movement of the engagement element relative to the output member by being attached to the output member in a state in which the engagement element is arranged between the first spacer section and the second spacer section in the axial direction; wherein, when a torque is applied to the input element, the engagement element moves away from the pressed surface in the first direction due to the engagement of the input-side engagement section with the input-side engagement section, and transmits the torque applied to the input element to the output element by bringing the output-side engagement section into engagement with the output-side engagement section; however, when a torque is applied in the opposite direction to the output element, the output-side engagement section engages with the output-side engagement section, and the pressing surface is pressed against the pressed surface, causing the pressing surface to come into frictional engagement with the pressed surface.
Clutch for blocking a reverse input after Claim 1 , wherein the output member has a small-diameter shaft section projecting from a central section of an end face or surface on a first side in an axial direction of the output-side engaging section towards the first side in the axial direction; the first spacer section has a first through-hole through which the output-side engaging section, the small-diameter shaft section or both are inserted; and the second spacer section has a second through-hole through which the output-side engaging section is inserted.
Clutch for blocking a reverse input after Claim 2 , wherein the retaining member has a locking projection section projecting from a surface facing an outer circumferential surface of the outward-engaging section or an outer circumferential surface of the small-diameter shaft section; and the outward-engaging section or the small-diameter shaft section has a locking groove on the outer circumferential surface at the same position in the axial direction as the locking projection section, with which the locking projection section engages.
Clutch for blocking a reverse input after Claim 3 , wherein a side surface or surface on a second side in the axial direction of the locking projection section has an inclined surface or surface section at least at one section on a tip end side in a projection direction of the locking projection section, wherein the inclined surface section is inclined in the direction towards the tip end side in the projection direction in a direction towards the first side in the axial direction.
Clutch for blocking a reverse input after Claim 4 , wherein a side face or surface on the first side is configured in the axial direction of the locking projection section by a flat surface or surface perpendicular to the axial direction of the pressed surface.
Clutch for blocking a reverse input after Claim 3 , wherein the locking projection section is configured by a plurality of locking projection sections provided at a plurality of locations spaced apart in a circumferential direction.
Clutch for blocking a reverse input after one of the Claims 3 until 6 , wherein the locking projection section projects from an inner circumferential surface or surface of the first through hole.
Clutch for blocking a reverse input after Claim 7 , wherein the first spacer section has a discontinuous section at least at one point in a circumferential direction.
Clutch for blocking a reverse input after Claim 7 , wherein the outer circumferential surface of the small-diameter shaft section comprises a small-diameter section representing a section on the first side in the axial direction, a large-diameter section representing a section on the second side in the axial direction, and a stepped surface or area facing the first side in the axial direction and connecting the small-diameter section and the large-diameter section; an outer diameter of the small-diameter section is equal to or less than a diameter of an incircle of the locking projection section; an outer diameter of the large-diameter section is greater than the diameter of the incircle of the locking projection section; and the locking groove is provided in the large-diameter section.
Clutch for blocking a reverse input after Claim 2 , wherein the input member has an input member-side restriction section which restricts movement of the holding member towards the first side in the axial direction relative to the output member by engaging with the first spacer section.
Clutch for blocking a reverse input after Claim 2 , comprising a retaining ring with a section on an inner surface in the radial direction, which engages with a section of the outer circumferential surface of the small-diameter shaft section, which is located further on the first side in the axial direction than the first spacer section; wherein movement of the retaining member towards the first side in the axial direction relative to the starting member is restricted by the first spacer section engaging with a side face or surface on the second side in the axial direction of a section on an outer surface in the radial direction of the retaining ring.
Clutch for blocking a reverse input after one of the Claims 1 until 11 , comprising a prestressing element which elastically prestresses the engagement element in one direction towards the pressed surface in the first direction.
Clutch for blocking a reverse input after Claim 12 , wherein movement of the prestressing member in the axial direction relative to the output member is restricted by the retaining member.
Clutch for blocking a reverse input after Claim 13 , wherein the preload member is arranged between the first spacer section and the second spacer section in the axial direction of the pressed surface and is configured by a leaf spring which is elastically sandwiched between the exit-side engaging section and the engagement element in the first direction.
Clutch for blocking a reverse input after Claim 13 , wherein the connecting section of the retaining member is configured by two connecting sections arranged on both sides of the first spacer section and the second spacer section in a second direction perpendicular to both the axial direction of the pressed surface and the first direction, each of the two connecting sections having a retaining hole extending in the first direction; and the preload member is configured by two compression helical springs that are internally fitted and retained in the retaining holes of the two connecting sections and elastically press sections on both sides in the second direction of a side face or surface of the engagement element on a side opposite the pressed surface in the first direction.
Clutch for blocking a reverse input after Claim 15 , comprising a press piece attached to an end section in an extension direction of each of the two compression helical springs; and the two compression helical springs elastically press the sections on both sides of the engagement element over the press pieces.
Clutch for blocking a reverse input after Claim 15 or Claim 16 , wherein the engagement element is configured by two engagement elements; the input-side engaging section is configured by two input-side engaging sections; the retaining hole by a penetrating through The access hole is configured to penetrate in the first direction; and the two compression helical springs are elastically compressed in the first direction between the two engagement elements.
Clutch for blocking a reverse input after Claim 17 , wherein at least one of the two connecting sections has a discontinuous section at a point in the circumferential direction of the retaining hole.
Clutch for blocking a reverse input after one of the Claims 1 until 16 , wherein the intervention element is configured by two intervention elements; and the input-side intervention section is configured by two input-side intervention sections.
Method for mounting a coupling to block a reverse input after Claim 17 or 19 , which includes the preload member; wherein the assembly method for the coupling for blocking a reverse input comprises one step: introducing the two engagement elements from the axial direction towards an inside in the radial direction of the pressed surface in a state in which the output member, the two engagement elements, the retaining member and the preload member are combined, and using an assembly device which engages the input-side engagement sections of the two engagement elements respectively, the two engagement elements are displaced against elastic preload forces of the preload member in directions which bring the two engagement elements closer together in the radial direction.

Description

TECHNICAL AREA The present disclosure relates to a coupling for blocking a reverse input, which transmits torque input into an input element to an output element and completely blocks torque that is reverse input into the output element and does not transmit the torque to the input element or transmits only part of the torque to the input element and blocks the rest. TECHNICAL BACKGROUND A reverse input blocking coupling has an input element connected to an input-side mechanism such as a drive source and an output element connected to an output-side mechanism such as a reduction mechanism, and has a function of transmitting torque input into the input element to the output element and simultaneously completely blocking the reverse torque input into the output element so that it is not transmitted to the input element, or of transmitting only part of the torque to the input element and blocking the remainder. Reverse input blocking couplings are broadly classified into locking and free-running types, depending on the mechanism that blocks the reverse torque applied to the output element. A locking-type reverse input blocking coupling incorporates a mechanism that prevents the output element from rotating when a reverse torque is applied. A free-running reverse input blocking coupling, on the other hand, incorporates a mechanism that allows the output element to rotate freely when a torque is applied. The choice between a locking-type and a free-running reverse input blocking coupling is appropriately determined by the application of the device in which the reverse input blocking coupling is integrated. Patent 2023/136149 describes a locking-type coupling for blocking a reverse input. This known coupling for blocking a reverse input includes a pressed element, an input element, an output element, and an engagement element. The pressed link has a pressed surface on one of its inner circumferential surfaces. The inlet element has an inlet-side engaging section which is arranged on an inside in a radial direction of the pressed surface and is arranged coaxially to the pressed surface. The output member has an output-side engaging section which is arranged further on the inside in the radial direction of the pressed member than the input-side engaging section, and is arranged coaxially to the pressed surface. The engagement element has a pressing surface facing the pressed surface, an inlet-side engagement section that can engage with the inlet-side engaging section, and an outlet-side engagement section that can engage with the outlet-side engaging section, and is arranged in such a way that it is able to move in a first direction which is a direction towards or away from the pressed surface. In this known coupling for blocking a reverse input, when torque is applied to the input element, the input-side engaging section engages with the input-side engagement section, causing the engagement element to move away from the pressed surface. As the output-side engagement section engages with the output-side engaging section, the torque applied to the input element is transmitted to the output element. Conversely, when a torque is applied in reverse to the output element, the output-side engaging section engages with the output-side engagement section, causing the engagement element to move towards the pressed surface. This presses the pressing surface against the pressed surface, bringing the pressing surface into frictional engagement with the pressed surface. LIST OF EDITED ITEMS PATENT LITERATURE Patent document 1: WO 2023/136149 BRIEF SUMMARY OF THE INVENTION TECHNICAL PROBLEM During the WO 2023/136149 The described coupling for blocking a reverse input has the possibility that, if movement in the axial direction of the engagement element relative to the input and output elements is not restricted, the engagement element may tilt in the axial direction. In a case where the engagement element moves radially outward while remaining tilted in the axial direction, the pressing surface and the pressed surface come into contact, resulting in local jamming. This leads to an unnecessary increase in the force required to change from a locked or half-locked state to an unlocked or half-unlocked state, or may cause plastic deformation of the pressing surface, the pressed surface, or both. In this known coupling for blocking a reverse input, two independent spacers are provided on both sides in the axial direction of the engagement element, and the two spacers restrict movement in the axial direction of the engagement element relative to the input element and the output element. However, using two spacers that are independent of each other increases the number of parts, which brings disadvantages such as increased costs to manage the parts and an increase in the number of assembly steps. One objective of the present disclosure is to provide a coupling structure for blocking a reverse input which can restrict movement in the a