Roller cage element having profiled rollers for a roller screw drive

Abstract

Proposed is a roller cage element for a roller screw drive, having profiled rollers (1) which are arranged around a longitudinal axis of a roller cage (2), in the cage pockets (3) of which roller cage the profiled rollers (1) are spaced from one another in the circumferential direction, the end pins (11) of which profiled rollers engage in bearing pockets (12) of rim rings (5) of the roller cage (2), characterized in that the bearing pockets (12) are radially open for the radial insertion of the profiled rollers (1) and each have an operating seat (13, 21) for the profiled rollers (1) and have an assembly seat (14, 20) for the profiled rollers (1) which is radially spaced from the operating seat (13, 21), in which assembly seat the profiled rollers (1) are held so as to be prevented from falling out of the roller cage (2) radially, wherein, for the assembly of the roller cage element, the profiled rollers (1) are arranged on a first pitch circle (TK1) arranged around the cage axis and, for the operation of the roller screw drive, said profiled rollers are arranged on a second pitch circle (TK2) arranged around the cage axis.

Description

[0001] Roller cage element with profile rollers for a rolling screw drive

[0002] The present invention relates to a roller cage element for a rolling screw drive, with profile rollers that are rotatably mounted in a roller cage.

[0003] US 10,584,777 B2 discloses a roller screw drive designed as a roller cage. A roller cage element has profile rollers arranged around a longitudinal axis of a roller cage, in whose cage pockets the profile rollers are arranged at a distance from one another in the circumferential direction. End pins of the profile rollers engage in bearing pockets of flange rings of the roller cage. The end pins have a cylindrical section and, in this particular case, a gear section that meshes with a ring gear of the nut of the roller screw drive. This roller screw drive is thus synchronized.

[0004] The roller cage has circumferentially distributed webs arranged along the rotational axis, with the flange rings located at their axial ends. Adjacent webs define U-shaped cage pockets for accommodating the profile rollers. These cage pockets keep the profile rollers spaced apart around the circumference. The cage pockets, which open radially inward, are helpful for inserting the profile rollers with their cylindrical pins into the roller cage from the radial inside. The roller cage element is screwed onto a threaded spindle of the rolling screw drive. For assembly, measures must be taken to enable the roller cage element to be mounted onto the threaded spindle of the rolling screw drive.

[0005] The object of the invention was to provide a roller cage element for a rolling screw drive that can be easily mounted on a threaded spindle or in a nut of the rolling screw drive. According to the invention, this object was achieved by the roller cage element for a rolling screw drive according to claim 1. Appropriate further developments and methods for mounting the roller cage element are specified in claims 2 to 10.

[0006] The roller cage element for a rolling screw drive has profile rollers arranged around a longitudinal axis of the roller cage. The longitudinal axes of the roller cage and the rolling screw drive coincide.

[0007] The profile rollers can be provided with a helical thread wound around the roller axis on the outer circumference, which meshes with a nut-side and / or a spindle-side thread.

[0008] The profile rollers can be provided with a plurality of parallel, consecutively arranged grooves and teeth, which are arranged transversely to the roller axis. Such profile rollers can be used in planetary roller screw drives and roller screw drives. In planetary roller screw drives, the profile rollers, designed as planetary rollers, rotate both around their roller axis and around the axis of a threaded spindle. In the case of a roller screw drive, the profile rollers can rotate around their roller axis and, for example, be arranged stationary.

[0009] The profile rollers are arranged at a distance from one another in the circumferential direction in cage pockets of the roller cage. This circumferential spacing and the sequence of profile rollers in the circumferential direction depend on the type and pitch of the rolling screw drive. For example, in the case of a planetary rolling screw drive, the profile rollers designed as planetary rollers mesh with the thread of a lead screw of the screw drive. The planetary rollers distributed around the circumference must be designed and positioned according to the pitch of the lead screw thread if their axial end faces are to lie in common planes.

[0010] The roller cage can preferably have webs distributed around the circumference and arranged along the rotation axis, at whose axial ends the flange rings are arranged. Adjacent webs define the cage pockets for accommodating the profile rollers. The webs and the flange rings can be manufactured as a single piece; alternatively, they can also be individual components that are positively connected to one another, for example, in the form of a plug-in connection.

[0011] The end pins of the profile rollers engage in the bearing pockets of the roller cage's rim rings. The profile rollers are mounted in the bearing pockets so they can rotate around the axis of the cylindrical pins. The bearing pockets are distributed around the circumference of the rim rings and determine the circumferential spacing of the profile rollers.

[0012] The bearing pockets are radially open for radial insertion of the profile rollers and each have an operating seat for the profile rollers and a mounting seat for the profile rollers, spaced radially from the operating seat. For example, the bearing pockets can be U-shaped in the axial direction and open either radially outward or radially inward.

[0013] The profile rollers can be inserted into the radially open side of the bearing pockets, with the pins engaging into the bearing pockets. To install the roller cage element, the profile rollers are inserted radially into the bearing pockets until they have reached their mounting position. The mounting position can be designed so that the pins of the profile rollers snap into it. A specific embodiment is described below.

[0014] In any case, the profile rollers are held captively in the mounting seat and do not easily fall out of the bearing pockets. The mounting seat enables the roller cage element to be mounted, for example, with a threaded spindle. This means that the inner enveloping circle diameter of the roller cage element is larger than the enveloping circle diameter of the threaded spindle; the profile rollers of the cage element do not interfere with the pushing together of the threaded spindle and the roller cage element. If the roller cage element is to be mounted with a nut of the screw drive, the outer enveloping circle diameter of the roller cage element is smaller than the enveloping circle diameter of the nut on its inner circumference. The enveloping circle diameter encloses a body whose greatest extent is equal to the diameter of the enveloping circle. An outer enveloping circle diameter encloses an outer contour of the body.An inner enveloping circle lies within a hollow body that is tangent to the inner enveloping circle at its narrowest point.

[0015] When the roller cage element is mounted with other essential components of the rolling screw drive, the profile rollers are moved out of their mounting seat in the bearing pockets by radial displacement and radially displaced into their operating seat, where they mesh with their assigned rolling partner, i.e. with a threaded spindle or with a nut of the rolling screw drive.

[0016] The mounting location of the profile rollers is located on a first pitch circle around a cage axis of the roller cage. This pitch circle is dimensioned so that the profile rollers do not collide with the rolling element into or onto which they are pushed during assembly of the roller cage element.

[0017] If the roller cage element is to be slid onto a threaded spindle, the inner diameter of the roller cage element is larger than the outer diameter of the threaded spindle. If the roller cage element is to be inserted into a nut, the outer diameter of the roller cage element is larger than the inner diameter of the nut.

[0018] When the roller cage element is assembled with the intended rolling partner and the profile rollers have been moved from their assembly seat to the operating seat by radial displacement, the profile rollers mesh with their rolling partner, i.e. with the threaded spindle or with the nut of the rolling screw drive.

[0019] The first and second pitch circles are located on different pitch circles around the cage axis, whose diameters are designed according to the function of the mounting seat and the operating seat. If the roller cage element is to be mounted with a threaded spindle, the first pitch circle for the mounting seat is larger than the second pitch circle for the operating seat.

[0020] If the roller cage element is to be mounted with a screw drive nut, the first pitch circle for the mounting seat is smaller than the second mounting seat for the operating seat.

[0021] The invention therefore enables easy assembly of the roller cage element with the intended rolling partner, i.e. threaded spindle or nut, without the need for additional components.

[0022] The bearing pockets are preferably each circumferentially limited by opposing pocket walls on each flange ring, which form pairwise holding sections for the profile rollers in the radial direction, each holding section being assigned to one of the two pitch circles.

[0023] Two opposing and facing pocket walls thus form a pair of holding sections. This holding section forms the mounting seat for the profile rollers. Similarly, another radially spaced holding section can form the operating seat. In the mounting seat and the operating seat, the profile rollers can be enclosed at their journals by the pocket walls of the roller cage's rim rings to such an extent that the profile rollers are held captively in the mounting seat and reliably supported in the operating seat.

[0024] The aforementioned retaining section can be formed by two circumferentially opposite, facing curved wall sections of the pocket walls. These can be part-circular, i.e., adapted to the diameter of the pin of the profile roller. Viewed in the axial direction, the wall sections are thus concavely curved. When the profile rollers are inserted into the roller cage, they can snap into this retaining section. This snap-in action can be ensured by appropriately shaping the pocket walls and selecting a suitable material with sufficiently high elasticity. The wall sections can be concave.

[0025] The pocket walls can preferably each have two curved wall sections arranged radially one behind the other in the axial direction, which partially encompass the journals of the profile rollers, wherein a clear distance between two opposite curved wall sections assigned to one of the two pitch circles is smaller than a journal diameter of the journals of the profile rollers. More generally, the bearing pocket can have a clear opening width that is smaller than the diameter of the journals.

[0026] For mounting the roller cage element onto a threaded spindle of the rolling screw drive, a method is proposed that involves the following steps. The profile rollers are placed in the roller cage into their mounting seat, where the roller cage element has an inner enveloping circle diameter that is larger than the outer diameter of the threaded spindle. The imaginary enveloping circle is large enough to touch the profile rollers arranged around the circumference. The roller cage element and the threaded spindle are then pushed into one another without the profile rollers coming into contact with the threaded spindle. After this pushing into one another, the profile rollers are radially displaced inward into the operating seat, where the profile rollers engage with the threaded spindle. A nut of the rolling screw drive is then screwed onto the roller cage element.

[0027] For assembling the roller cage element with a nut of the rolling screw drive, a method is proposed that involves the following steps. The profile rollers are inserted into the roller cage in the assembly seat, where the roller cage element has an outer enveloping circle diameter that is smaller than the inner diameter of the nut. The imaginary enveloping circle is large enough to touch the profile rollers arranged around the circumference. The roller cage element is then inserted into the nut without the profile rollers coming into contact with the nut. The profile rollers are then radially displaced into the operating seat, where they engage with the nut. A threaded spindle is then screwed into the roller cage element.

[0028] The nut can be a two-part nut element composed of rings, or it can be a one-part profile nut.

[0029] The invention is explained in more detail below with reference to two exemplary embodiments illustrated in a total of 12 figures. They show:

[0030] Figure 1 shows a first embodiment of a roller cage element in perspective view,

[0031] Figure 2 shows a cage of the roller cage element from Figure 1 in perspective view,

[0032] Figure 3 shows the roller cage element from Figure 1 in a side view, in assembly position,

[0033] Figure 4 shows the roller cage element from Figure 3 in operating position,

[0034] Figure 5 is an enlarged detail of Figure 3,

[0035] Figure 6 is a further enlarged detail of the cage of the roller cage element of Figure 3,

[0036] Figure 7 is a schematic representation of the roller cage element with a threaded spindle of a screw drive, in assembly position,

[0037] Figure 8 is a schematic representation of the roller cage element as in Figure 7, in operating position,

[0038] Figure 9 shows another embodiment in perspective view,

[0039] Figure 10 is an enlarged detail of Figure 9,

[0040] Figure 11 is a schematic representation of the embodiment according to Figure 9 with a nut of a screw drive, in a mounting position of the roller cage element and

[0041] Figure 12 is a schematic representation as in Figure 11, in the operating position of the roller cage element.

[0042] The embodiment shown in Figures 1 to 8 shows a first embodiment of a roller cage element for a rolling screw drive, with profile rollers 1 which are arranged around a longitudinal axis of a roller cage 2, in the cage pockets 3 of which the profile rollers 1 are arranged at a distance from one another in the circumferential direction.

[0043] The roller cage 2 has webs 4 distributed over the circumference and arranged along the axis of rotation, at the axial ends of which flange rings 5 ​​are arranged, wherein webs 4 arranged adjacent to one another delimit cage pockets 3 for receiving the profile rollers 1.

[0044] The profile rollers 1 have a larger engagement profile 7 for engagement with a spindle-side thread 8 of a threaded spindle 9 (see Figure 8). On both sides of the larger engagement profile 7, a smaller engagement profile 10 is formed on the profile roller 1 for engagement with a nut-side profile of a nut of the screw drive (not shown).

[0045] Figures 3 and 4 show that the profile rollers 1 are provided with pins 11 at their axial ends, which engage in bearing pockets 12 of the flange rings 5 ​​of the roller cage 2. The bearing pockets 12 can be clearly seen, for example, in Figure 2. Viewed in the axial direction, the bearing pockets 12 each have a U-shaped contour, opening radially outward.

[0046] The bearing pockets 12 each have an operating seat 13 for the profile rollers 1 and a mounting seat 14 for the profile rollers 1, spaced radially from the operating seat 13 (see Figure 5). The mounting seat 14 secures the profile rollers 1 against radially falling out of the roller cage 2.

[0047] The profile rollers 1 are inserted radially from the outside into the bearing pockets 12, causing elastic deformation of the pocket walls 15, and snap into their mounting seat 14. By radial displacement, the profile rollers 1 are snapped into their operating seat 13, causing elastic deformation of the pocket walls 15.

[0048] Figure 6 shows an enlarged detail of the radially outer mounting seat 14 for the profile rollers 1 for mounting the roller cage element, as well as the operating seat 13 for the profile rollers 1. In the mounting seat 14, the profile rollers 1 are arranged on a first pitch circle TK1 arranged around the cage axis, and for operating the rolling screw drive, on a second pitch circle TK2 arranged around the cage axis (see Figures 3 and 4). The rotation axes of the profile rollers 1 lie on the first pitch circle TK1 in the mounting seat and on the second pitch circle TK2 in the operating seat.

[0049] Figure 6 clearly shows that the bearing pockets 12 are each circumferentially delimited by opposing pocket walls 15, which are distributed over the circumference of both flange rings 5. In pairs, the two opposing pocket walls 15 form two radially arranged holding sections 16, 17 for the profile rollers 1 in the radial direction.

[0050] The radially outer holding section 16 for the mounting seat 14 is formed by curved wall sections 18 on both pocket walls 15, which encompass the pins 11 of the profile rollers 1 over a partial circumference, wherein, viewed from the radial outside, a clear distance between the two opposing curved wall sections 18 is smaller than a pin diameter of the pins 11 of the profile rollers 1.

[0051] The radially inner holding section 17 for the operating seat 14 is formed by curved wall sections 19 on both pocket walls 15, which encompass the pins 11 of the profile rollers 1 over a partial circumference, wherein, viewed from the radial outside, a clear distance between the two opposite curved wall sections 19 is smaller than a pin diameter of the pins 11 of the profile rollers 1.

[0052] Figures 7 and 8 show two assembly steps. In the first assembly step (Figure 7), the profile rollers 1 are snapped into the assembly seat 14.

[0053] Figure 7 clearly shows that an inner enveloping circle diameter of the roller cage element is larger than an outer diameter or enveloping circle diameter of the threaded spindle 9. The roller cage element can be pushed onto the threaded spindle 9 without disturbing contact with the threaded spindle 9.

[0054] Figure 8 shows the roller cage element with the profile rollers 1 in the operating seat 13, which mesh with the threaded spindle 9.

[0055] A nut element (not shown) can then be screwed onto the profile roller element.

[0056] The embodiment shown in Figures 9 to 12 differs from the first embodiment essentially by a radially interchanged arrangement of the assembly seat and the operating seat as well as by radially continuously open bearing pockets 22 in the flange rings 5.

[0057] Figures 9 and 10 show that the bearing pockets 22 are radially open throughout. A mounting seat 20 is located radially inside and an operating seat 21 is located radially outside in the bearing pockets 22. In the mounting seat 20, the profile rollers lie on a radially inner first pitch circle TK1. In the operating seat, the profile rollers 1 lie on a radially outer second pitch circle TK2.

[0058] As in the previously described embodiment, pocket walls 29 of the bearing pockets 22 are designed as curved wall sections 25, 26 arranged radially one behind the other. Circumferentially opposite curved wall sections 25, 26 form holding sections 27, 28 for the profile rollers 1 in the assembly seat 20 and the operating seat 21.

[0059] According to this exemplary embodiment, the assembly sequence is such that first the profile rollers 1 are radially inserted into the roller cage 2 in the assembly seat 20 and, similar to the previously described exemplary embodiment, snap into the assembly seat 20, in which the roller cage element has an outer enveloping circle diameter that is smaller than the inner diameter of a nut element 23, which in the exemplary embodiment is formed from individual nut rings 24. The roller cage element and the nut element 23 are then pushed into one another. Figure 11 clearly shows that there is a radial distance between the profile rollers 1 and the nut element 23, so that unwanted contact during assembly is excluded.

[0060] In the next step, the profile rollers 1 are moved into the operating seat 21, where the profile rollers 1 engage with the nut element 23. This assembly step is shown in Figure 12.

[0061] The threaded spindle 8 (not shown here) can then be screwed in

[0062] List of reference symbols

[0063] Profile roller

[0064] roller cage

[0065] Cage bag

[0066] web

[0067] Bordring

[0068] engagement profile spindle-side thread threaded spindle smaller engagement profile pin bearing pocket operating seat assembly seat pocket wall holding section holding section curved wall section curved wall section assembly seat operating seat bearing pocket nut element nut ring curved wall section curved wall section holding section holding section pocket wall

Claims

Patent claims 1. Roller cage element for a rolling screw drive, with profile rollers (1) arranged around a longitudinal axis of a roller cage (2), in whose cage pockets (3) the profile rollers (1) are arranged at a distance from one another in the circumferential direction, the end pins (11) of which engage in bearing pockets (12) of flange rings (5) of the roller cage (2), characterized in that the bearing pockets (12) are radially open for the radial insertion of the profile rollers (1) and each have an operating seat (13, 21) for the profile rollers (1) and a mounting seat (14, 20) for the profile rollers (1), which is radially spaced from the operating seat (13, 21), in which the profile rollers (1) are held against radial falling out of the roller cage (2),wherein the profile rollers (1) are arranged on a first pitch circle (TK1) arranged around the cage axis for mounting the roller cage element and are arranged on a second pitch circle (TK2) arranged around the cage axis for operating the rolling screw drive.

2. Roller cage element according to claim 1, the roller cage (2) of which has webs (4) distributed over the circumference and arranged along the longitudinal axis, at the axial ends of which the flange rings (5) are arranged, wherein webs (4) arranged adjacent to one another delimit cage pockets (3) for receiving the profile rollers (1).

3. Roller cage element according to claim 1 or 2, the bearing pockets (12) on each flange ring (5) are each delimited in the circumferential direction by opposing pocket walls (15, 29) which form pairs of holding sections (16, 17, 27, 28) for the profile rollers (1) in the radial direction, each holding section (16, 17, 27, 28) being assigned to one of the two partial circles (TK1, TK2).

4. Roller cage element according to claim 3, the pocket walls (15, 29) of which, viewed in the axial direction, each have two radially successive curved wall sections (18, 19, 25, 26) which encompass the journals (11) of the profile rollers (1), wherein a clear distance between two of the two pitch circles (TK1, TK2) arranged, opposite curved wall sections (18, 19, 25, 26) is smaller than a pin diameter of the pins (11) of the profile rollers (1).

5. Roller cage element according to one of claims 1 to 4, whose bearing pocket (12, 22) has a clear opening width which is smaller than the diameter of the pins (11).

6. Roller cage element according to one of claims 1 to 4, whose first pitch circle diameter (TK1) in the assembly seat (14, 20) is larger than the second pitch circle diameter (TK2) in the operating seat (13, 21).

7. Roller cage element according to one of claims 1 to 4, whose first pitch circle diameter (TK1) in the assembly seat (14, 20) is smaller than the second pitch circle diameter (TK2) in the operating seat (13, 21).

8. Roller cage element according to one of claims 1 to 6, the bearing pockets (12) of which each have a U-shaped contour when viewed in the axial direction.

9. Method for mounting the roller cage element according to claim 6 on a threaded spindle (9) of the rolling screw drive according to the following steps: • Inserting the profile rollers (1) into the roller cage (2) in the assembly seat (14), in which the roller cage element has an inner enveloping circle diameter that is larger than the outer diameter of the threaded spindle (9), • Attaching the roller cage element to the threaded spindle (9) • Radial displacement of the profile rollers (1) into the operating seat (13), in which the profile rollers (1) are in engagement with the threaded spindle (9) • Screwing a nut onto the roller cage element.

10. Method for assembling the roller cage element according to claim 7 into a nut element (23) of the rolling screw drive according to the following steps: • Inserting the profile rollers (1) into the roller cage (2) in the assembly seat (20), in which the roller cage element has an outer enveloping circle diameter that is smaller than an inner diameter of the nut element (23) • Insert the roller cage element into the nut element (23) • Radial displacement of the profile rollers (1) into the operating seat (21) in which the profile rollers (1) are in engagement with the nut element (23) • Screwing a threaded spindle into the roller cage element.

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