Clamping element freewheel

Abstract

Clamping element freewheel with an inner ring and an outer ring (12) which together form an annular gap which is limited on its inner or outer circumference by a clamping contour, a number of clamping elements (20) which are held in a cage (18) in the annular gap, and a spring-loaded device by which the clamping elements (20) are pre-tensioned into a clamping position in which they clamp against the clamping contour (22), characterized in that the spring-loaded device has a spring element (26) which extends axially through the annular gap and engages with one end the cage (18) and with the other end a stop (28) which is formed on the inner ring or the outer ring.

Description

The invention relates to a clamping body freewheel having an inner ring and an outer ring, which together form an annular gap which is bounded on its inner or outer circumference by a clamping contour, a number of clamping bodies which are held in a cage in the annular gap, and a spring-action device, by means of which the clamping bodies are prestressed into a clamping position in which they bear in a clamping manner against the clamping contour.DE 10 2022 112 702 A1 discloses a clamping body freewheel of this type, in which the springing device is formed by an annular spring, which is in frictional contact with the inner ring (or optionally the outer ring) and therefore exerts a torque on the cage during a relative movement between the inner ring and the cage.Another known solution consists in individually springing each clamping body by means of spring elements formed in each clamping body cell of the cage.It is an object of the invention to provide a clamping body freewheel which is distinguished by a reduced idling torque.This object is achieved according to the invention in that the springing device has a spring element which extends axially through the annular gap and acts with one end on the cage and with the other end on a stop which is formed on the inner ring or the outer ring.Since the spring element extends axially through the annular gap, it can have a relatively large length and therefore be designed without impairing the stability such that it has only a very small spring constant and therefore elastically pretensions the clamping bodies into the clamping position only with very little force. Therefore, even a very low torque in the idling direction is sufficient to release the clamping bodies from their clamping position.The spring-on device can be produced easily in this way and does not require any additional installation space.Advantageous embodiments of the invention are specified in the dependent claims.In one embodiment, the spring element may be a flexure spring formed integrally with the cage.In another embodiment, the spring element can be formed separately from the cage and can be formed, for example, by an elastic wire which is anchored at one end to the cage.The spring element can be arranged, for example, in an empty cage cell which is open at its end facing the stop. Alternatively, two or more spring elements can also be provided, so that a more symmetrical distribution of the clamping bodies results.If the outer ring is in the form of a sleeve which is closed off at one end by a base, the stop can be formed on or in this base of the sleeve.Exemplary embodiments are explained in more detail below with reference to the drawings.The following are shown: FIG. 1 shows an axial section through a clamping body freewheel according to the invention; FIG. 2 is a sectional view taken along the line II--II in FIG. 1; and FIG. 3 shows an axial section through a clamping body freewheel according to another exemplary embodiment.The freewheel shown in FIG. 1 comprises a sleeve 10, the circumferential wall of which forms an outer ring 12 of the freewheel and which is closed at one end by a base 14. An inner ring 16 (FIG. 2 ), which is not shown in FIG. 1, forms with the outer ring 12 an annular gap which accommodates a number of clamping bodies 20 held in a cage 18. In the example shown, the clamping bodies 20 have the form of rollers.As can be seen in FIG. 2, the inner circumferential surface of the outer ring 12 forms a clamping contour 22, which is shaped such that the annular gap narrows in the clockwise direction in the vicinity of each of the clamping bodies 20. It can also be seen in FIG. 2 that one of the cells of the cage 18 which accommodate the clamping bodies 20 is not occupied. In FIG. 1, this unoccupied cell is seen, which is denoted by the reference sign 24 and which, in contrast to the remaining cells, is open toward the side of the base 14 of the sleeve 10. From the opposite end of the cell 24 there projects centrally a spring element 26 which extends virtually over the entire axial length of the freewheel and bears with its free end against a stop 28. In this example, the stop 28 is formed by the edge of a recess 30 in the base 14 of the sleeve 10.As FIG. 1 shows, the spring element 26 is elastically deflected, so that it rests against the stop 28 under a certain prestress. This applies a torque to the cage 18 which tends to rotate the cage in a clockwise direction in FIG. 2. As a result, the clamping bodies 20 have been displaced into a clamping position in which they are held in a clamping manner in the narrowing part of the annular gap between the inner ring and the outer ring. This also prevents the inner ring 16 from rotating clockwise in a clamping manner.On the other hand, when a counter clockwise torque acts on the inner ring 16, the clamping bodies 20 are carried along in the direction in which the annular gap expands, thereby releasing the clamping, so that the inner ring 16 can freely rotate in the counter clockwise direction. During the movement out of the clamping position, the clamping bodies 20 rotate the cage 18 somewhat in the counterclockwise direction in FIG. 2 counter to the force of the spring element 26, During this rotation, the cell 24 of the cage moves upward in FIG. 1, so that the spring element 26 is deflected more strongly.The more flexurally rigid the spring element 26 is, the greater is the torque required to release the clamping bodies 20 from the clamping position and to unlock the freewheel.The design of the spring element 26 shown here, however, has the advantage that the free end of the spring element presses via a large lever arm onto the stop 28, so that the force exerted on the stop is correspondingly low. Accordingly, the counter torque exerted on the cage is also so low that the freewheel can be unblocked even with a low torque. In addition, the spring constant of the spring element 26 can be finely metered by suitable selection of the thickness of this spring element.In the example shown in FIGS. 1 and 2, the spring member 26 is formed integrally with the cage 18. FIG. 3 shows an alternative embodiment in which the spring element 26' is formed separately from the cage 18. In Figure 3, the spring element 26' is an elastic wire passing through the end wall of the cage 18 which bounds the cell 24. The wire then enters an annular groove 32 in the end face of the cage 18 and then follows this annular groove a certain distance in the circumferential direction, whereby a secure anchoring of the spring element in the cage is achieved.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2022 112 702 A1

[0002]

Claims

A clamping body freewheel comprising an inner ring (16) and an outer ring (12) which together form an annular gap which is bounded on its inner or outer circumference by a clamping contour (22), a number of clamping bodies (20) which are held in the annular gap in a cage (18), and a spring-on device by which the clamping bodies (20) are prestressed into a clamping position in which they bear clampingly against the clamping contour (22), characterized in that the spring-on device has a spring element (26; 26') which extends axially through the annular gap and acts with one end on the cage (18) and with the other end on a stop (28) which is formed on the inner ring or the outer ring.A clamp freewheel as claimed in claim 1, wherein the cage (18) includes a cell (24) open at its end facing the stop (28), and wherein the spring member (26; 26') is anchored to the cage (18) at the opposite end of the cell (24) and extends freely through the interior of the cell.The clamping body freewheel according to claim 2, wherein the cell (24) which receives the spring element (26; 26') and further cells of the cage which receive the clamping bodies (20) are arranged in a uniform grid.The clamping body freewheel according to claim 3, comprising a plurality of spring elements which are accommodated in associated cells (24) in positions distributed uniformly on the circumference of the cage.The clamping body freewheel according to any one of the preceding claims, wherein the spring element (26) is a flexible spring which is formed in one piece with the cage (18).Clamping body freewheel according to one of Claims 1 to 4, in which the spring element (26) is a flexurally elastic element which is formed separately from the cage (18) and is anchored to the cage.Clamping body freewheel according to Claim 6, in which one end of the spring element (26') is accommodated in an annular groove (32) of the cage (18).Clamping body freewheel according to one of the preceding claims, in which the outer ring (12) is part of a sleeve (10) closed by a base (14), and the base (14) of the sleeve forms the stop (28) for the spring element (26; 26').

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