Cage free wheel having bearing roller

Abstract

To facilitate the attachment and installation of a cage free wheel to a shaft / hub connecting part, and to improve functionality.SOLUTION: In a cage free wheel installed in a crank gap in a drive part of, in particular, an electric bicycle, bearing rollers for supporting a hub and a shaft to each other continuously in a circumferential direction, and a rotatably-arranged clamp body are arranged at a cage. The clamp body locks relative motions between the shaft and the hub in one rotation direction in terms of friction locking, and permits the relative motions in the other direction. The clamp body is spring-energized in a clutch-in direction by a ring-shaped spring which extends around a row in a slit of a face at the outside of a radial direction, and the bearing rollers are arranged in pockets correlated with the cage at both sides of the ring-shaped spring at each of a pair of the bearing rollers. The bearing rollers are arranged so as to be accommodated in the corresponding pockets in the radial direction so as to be relatively supplementarily engaged with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention relates to a cage freewheel according to the preamble of claim 1, for installation in the clamping gap between the shaft / hub connection, in particular in the drive of an electric bicycle. [Background technology]

[0002] Cage freewheels are known in numerous embodiments, see for example DE 102009030614 A1 and DE 102011108413 A1 by the same applicant.

[0003] It is important for a freewheel that the shaft and the hub (in which the freewheel is installed in the clamping gap between them) must be supported relative to each other with as little radial play as possible. Usually, this is achieved by an additional roller bearing separate from the freewheel. However, this increases the axial constructional size of the shaft / hub connection. In various applications, particularly in the bottom brackets of electric vehicle drives, the smallest possible axial constructional size is desired.

[0004] German Patent Application No. 10 2019 2018 785 A1 discloses a cage freewheel in which bearing rollers and clamping bodies are arranged in a circumferential sequence. The bearing rollers are used to support the shaft and hub relative to each other. The clamping bodies are rotatably arranged so that they frictionally lock the relative movement between the shaft and hub in one rotational direction and allow it in the other. Ring-shaped springs extending around the row of clamping bodies in slots in the radially outer surfaces of the clamping bodies ensure a spring bias of the clamping bodies in the clutch-in direction. Each pair of bearing rollers is located in an associated pocket of the cage ring on both sides of the ring-shaped spring. The bearing rollers thus integrate a roller bearing function into the cage freewheel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] German Patent Application Publication No. 102009030614 [Patent Document 2] German Patent Application Publication No. 102011108413 [Patent Document 3] German Patent Application Publication No. 1020192018785 [Patent Document 4] U.S. Patent No. 6,279,708 Summary of the Invention [Problem to be solved by the invention]

[0006] A drawback of such cage freewheels is their laborious and complicated installation. While the clamping body is held from the outside by the ring spring that surrounds the cage freewheel and is protected from falling, the bearing rollers located on both sides of the ring spring are prone to falling when the cage is installed. In addition, the axial position of the rollers is not fixed, making installation of the ring spring difficult and leading to collisions between the rollers and the ring spring. Such collisions can cause malfunctions of the cage freewheel. It is therefore an object of the present invention to propose a cage freewheel that is easier to install and install on a shaft / hub connection and / or improves the functionality of the cage freewheel.

[0007] U.S. Patent No. 6,279,708 shows a freewheel with integrated ball bearings, in which a row of ball bearings and a row of clamping bodies are arranged adjacent to each other between an inner ring and an outer ring. The balls and clamping bodies are arranged in a cage, which accommodates the balls in a complementary engagement between the inner and outer rings in the axial direction. Again, there is a risk of the balls falling out in the radial direction during installation or when the inner and outer rings are removed. [Means for solving the problem]

[0008] This problem is solved by the features of claim 1. Advantageous embodiments result from the respective dependent claims.

[0009] In a cage freewheel of the type mentioned at the outset, the invention provides that the bearing rollers are accommodated in a radially complementary manner in their associated (first) pockets in the ring-shaped cage. This not only facilitates the installation of the cage during the manufacture of the cage freewheel, but also the subsequent installation of the cage freewheel between the shaft and the hub, since the bearing rollers can no longer fall out and be lost. This provides the user with an assembly that can be easily inserted into the ring gap between the shaft and the hub.

[0010] The complementary accommodation of the rollers in the freewheel cage can also be achieved by assembling the freewheel cage using several cage parts that are latched together during installation. However, a particularly advantageous design is achieved if the freewheel cage is manufactured from elastically deformable plastic, in particular as an injection-molded part, so that the bearing rollers are clipped into their pockets by elastic deformation of the cage. This allows the cage to be constructed in one piece. The installation of the bearing rollers can be carried out either before or after the installation of the clamping bodies and the insertion of the ring springs, by simply pressing the bearing rollers into their associated pockets from the outside or inside.

[0011] In a preferred embodiment, the pockets for the bearing rollers have a width on the circumferential surface of the cage that corresponds at least to the circumference of the bearing rollers and have at least one, preferably two, pairs of protrusions that protrude into the pockets, via which the bearing rollers are held in a radially complementary engagement in the pockets. This reduces the required mounting force, since the freewheel cage only needs to deform in the region of the protrusions, rather than along the entire length of the bearing rollers. The larger the gap between the protrusions and the smaller their radial extent, the smaller the required deformation force. If the pockets have corresponding protrusions not only on the outer circumferential surface of the cage but also on the inner circumferential surface of the cage, the bearing rollers can be selectively pressed into their pockets from the inside or the outside.

[0012] Preferably, the bearing rollers are positioned axially by the inner surfaces of the side edges of the cage and by a central bar separating the pockets arranged in pairs, the width of the bar between the pockets being preferably greater than the diameter or width of the ring springs.

[0013] Preferably, the cage freewheel has at least three, preferably five, pairs of bearing rollers distributed around the circumference of the cage in their associated pockets. Here, a plurality of (second) pockets, each containing a clamping body, are provided circumferentially between the (first) pockets containing the bearing rollers. At least three, preferably five, pairs of rollers ensure reliable radial alignment of the shaft component and the hub component relative to each other. The remaining space in the circumferential direction can be utilized for the clamping bodies, thereby providing a sufficiently high clamping surface for transmitting forces occurring in the locking direction between the shaft and hub. Preferably, at least two, more preferably at least four, clamping bodies are arranged consecutively in the circumferential direction, followed by another bearing roller in the circumferential direction. Thus, the cage freewheel has at least two, preferably at least four, times as many clamping bodies as bearing rollers. Essentially, the more clamping bodies available, the higher the torque that can be transmitted in the locking direction of the freewheel.

[0014] Alternatively, the bearing rollers may be connected to each other in pairs via a common shaft within their respective pockets, or may be integrally formed with the common shaft. When the bearing rollers are installed from the outside, they must be clipped into their respective pockets before the ring spring is attached. By integrally connecting the bearing rollers to both sides of the ring spring, it is possible to absorb a higher rotational torque between the shaft and the hub.

[0015] The pockets for the clamping bodies are preferably separated from one another by bars, the free spacing between the bars being determined such that it is greater than the radially inward lateral extension of the clamping bodies in the circumferential direction but less than the radially outward lateral extension. Since the clamping bodies cannot fall inward between the bars, it is possible to fit the clamping bodies into their pockets from the outside and then install the ring springs that hold the clamping bodies in the freewheel cage. The clamping bodies are thus held in the freewheel cage by the ring springs, while the bearing rollers are prevented from falling out radially by the complementary engagement.

[0016] Further advantages and embodiments will become apparent from the following description of exemplary embodiments with reference to the drawings. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is an isometric view of a cage freewheel with clamping bodies and bearing rollers. [Figure 2] FIG. 2 is an enlarged view of the freewheel cage of the cage freewheel shown in FIG. 1. [Figure 3] 3 is a diagram showing a cross section taken along the cutting line AA in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] The cage freewheel 1 shown in FIG. 1 comprises a ring-shaped cage 2 (cage ring) and clamping bodies 3 rotatably fitted within the cage in a manner known per se. The clamping bodies 3 have a central slit 4 into which a ring-shaped spring 5, e.g., a spiral spring, is fitted over the entire circumference of the row of clamping bodies, biasing the clamping bodies 3 in the clutch-in direction. The cage freewheel is used to install in a ring gap between a shaft component and a hub component, with the inner circumferential surface of the hub component and the outer circumferential surface of the shaft component each formed as a cylindrical track for the clamping bodies 3. The edge surfaces of the clamping bodies 3, oriented toward the inner or outer track of the shaft component or hub component, function as clamping wedges that immobilize the shaft component relative to the hub component in the rotational direction, i.e., the locking direction of the freewheel, thereby blocking relative rotation. In the opposite rotational direction, i.e., the free running direction, for example, the hub component is fixed, while the shaft component can rotate freely.

[0019] In principle, it is possible to fit the cage freewheel 1 according to the invention not directly between the shaft component and the hub component, but instead between the freewheel inner ring and the freewheel outer ring, which are then pressed onto the shaft component or pressed into the hub component, respectively, to form the cylindrical track for the clamping body 3.

[0020] To center the shaft component relative to the hub component within the shaft / hub connection, the cage freewheel 1 has additional bearing rollers 6, which in each pair are fitted into corresponding pockets 7 of the freewheel cage 2 on either side of the ring spring 5 and perform the function of roller bearings. Between each pair of rollers 6 there are four consecutive clamping bodies 3, so that there are four times as many clamping bodies distributed around the circumference as there are roller pairs.

[0021] The clamping body 3 of the clamping body freewheel, often also referred to as a clamping piece, is non-circular in structure and therefore has a long and a short lateral extension. In its long lateral extension, the clamping body 3 is slightly wider than the diameter of the bearing roller 6, so that during clutch engagement, the clamping body is sandwiched in a ring gap formed by the outer surface of the shaft part and the inner sliding surface of the hub part. In its short lateral extension, the clamping body 3 is slightly narrower than the diameter of the bearing roller 6, so that in the clutch engagement direction the clamping body slides along the sliding surface of the ring gap, spring-biased against the sliding surface.

[0022] The cage 2 is shown in more detail in Figure 2. It has two ring-shaped edge strips 9a, 9b which form the side edges of the cage and are connected to each other via an axially extending bar 10. Between the bars 10, receiving pockets 8 for the clamping bodies 3 are formed. Four pockets 8 for each clamping body 3 are followed by one pair of pockets 7 for the bearing rollers 6. When the cage freewheel is fully installed, the ring-shaped spring 5 stretches over the central bar 11.

[0023] The pockets 7 are shaped so as to accommodate the bearing rollers 6 in a complementary manner (positive locking). For this purpose, protrusions or cams 13 that protrude into the pockets are arranged radially inward and outward on separator bars 12 on the sides of the pockets 7. The circumferential distance a1 between the two cams 13 is smaller than the outer diameter of one bearing roller 6. A rounded contour 14 is formed between the inner and outer protrusions 13 of one separator bar 12, and this contour is adapted to the circumferential extension of the bearing rollers 6. The central distance a2 between the two opposing rounded contours 14 is selected to be slightly larger than the diameter of the bearing roller 6.

[0024] The cage 2 is manufactured using a high-grade plastic material such as polyamide or polyetheretherketone (PEEK) with certain elastic properties, so that the bearing rollers 6 can be pressed into the corresponding pockets 7 from the inside or outside for installation. Pressure on the bearing rollers 6 causes the associated pockets 7 to expand due to elastic deformation of the protrusions 13. After the bearing rollers 6 reach their radially central position, the deformation is relaxed and the bearing rollers 6 are held in the center of the pockets by the protrusions 13 and the curved contours 14.

[0025] The bearing roller 6 is axially positioned in the pocket 7 by the inner surface of the edge band 9a or 9b and the central bar 11. The width of the central bar 11 is greater than the outer diameter of the ring spring, which ensures that the bearing roller does not come into contact with the ring spring during installation and subsequent operation.

[0026] To mount the cage freewheel, the clamping bodies 3 can be first installed on the cage 2 by inserting them radially from the outside into the pockets 8. The circumferential distance between the two bars 10 is determined so that this distance is greater than the circumferentially oriented width of the radially inner lateral surface of the clamping bodies 3. However, since the radially outer width of the clamping bodies 3 is greater than the distance between the two separator bars 8, the clamping bodies 3 cannot fall inward through their own pockets 8. The ring springs 5 ​​are then placed around the clamping bodies 3, and finally the bearing rollers 6 can be pressed into their associated pockets 7. Similarly, it is also possible to first place the bearing rollers 6 in the pockets 7, and then fit the clamping bodies 3 into the pockets 8 so that the ring springs 5 ​​run around the outer periphery of the row of clamping bodies.

[0027] Thus, in the fully mounted cage freewheel, the clamping bodies 3 are held by the ring springs 5, while the bearing rollers 6 are held in their pockets in a complementary and non-destructive manner. The fully mounted cage freewheel can then be slid onto a shaft component and inserted together with the shaft component into the associated hub component to manufacture the freewheel, or vice versa, inserted into the hub component and then the shaft component pushed through.

[0028] The cage freewheel illustrated in the exemplary embodiment can be modified in many ways and still fall within the scope of the present invention. For example, instead of five pairs of bearing rollers, a greater or lesser number of bearing roller pairs can be used. For example, by distributing at least three bearing roller pairs at an angle of 120° around the circumference of the freewheel cage, more residual space is created for additional clamping bodies. The bearing rollers 6 of one bearing roller pair can also be connected to each other via a common central axis. In this case, the central bar 11 can be omitted or provided with a corresponding recess for the common axis of the bearing roller pairs 6. The axially inner front faces of the edge strips 9a and 9b can be provided with additional guide surfaces that limit the rotational movement of the clamping bodies. Similarly, the axially inner front faces of the edge strips 9a and 9b can be provided with pins that engage in corresponding recesses on the front side of the clamping bodies and thereby define the rotation axis for the clamping bodies. In this case, the clamping bodies can also be attached by light pressure and the resulting elastic deformation of the cage 2 until the pins fit into the recesses on the front side of the clamping bodies. It is also possible to provide corresponding pins on the clamping bodies and recesses for them on the front sides, inside the edge strips 9a and 9b. However, it is also possible, as shown in German Utility Model No. 202017106205, to design the cage in two parts, for example using two part rings that are latched together via a latching connection in the region of the bars 10, 12.

Claims

1. A cage-free wheel (1) having a ring-shaped cage (2) for installation in the clamp gap between a shaft and a hub, wherein the cage (2) is provided with bearing rollers (6) that support the hub and the shaft from each other, and a clamp body (3) rotatably disposed within the cage (2), wherein the clamp body (3) frictionally locks the relative movement between the shaft and the hub in one rotational direction and allows it in the other, and is spring-biased in the clutch-in direction by a ring-shaped spring (5) extending around a row of clamp bodies (3) in a slit (4) on the radially outer surface of the clamp body (3), the bearing rollers (6) are each disposed in pairs within associated pockets (7) of the cage (2) on both sides of the ring-shaped spring (5), and the bearing rollers (6) are radially coupled and complementary in the cage-free wheel, The cage-free wheel is characterized in that the bearing roller (6) is positioned axially by the inner surface of the cage side edge (9a, 9b) of the cage (2) and by a central bar (11) that separates the paired pockets (7) from each other.

2. The cage-free wheel according to claim 1, characterized in that the cage (2) is manufactured using an elastically deformable plastic, and the bearing roller (6) is clipped into its own pocket (7) by the elastic deformation of the cage (2).

3. The cage-free wheel according to claim 1 or 2, wherein the pocket (7) for the bearing roller (6) has a width on at least one circumferential surface of the cage (2) that corresponds to at least the circumference of the bearing roller (6), and has at least one pair of projections (13) that protrude into the pocket, and the bearing roller (6) is held within the pocket (7) in a radially complementary engagement manner via the projections.

4. The cage-free wheel according to claim 1 or 2, characterized in that at least three pairs of the bearing rollers (6) are distributed around the circumference of the cage (2) within associated pockets (7), and a plurality of pockets (8) containing clamp bodies (3) are provided circumferentially between the pockets (7) containing the bearing rollers (6).

5. The cage-free wheel according to claim 4, characterized in that at least two clamping bodies (3) are arranged in a continuous manner in the circumferential direction, followed by another bearing roller (6) in the circumferential direction.

6. The cage-free wheel according to claim 1 or 2, wherein the pockets (8) for the clamp body (3) are separated from each other by bars (10), and the free spacing between the bars (10) is determined such that the spacing is greater than the radially inner width but less than the radially outer width, with the spacing oriented circumferentially to the clamp body (3).

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