Support assembly having a shaft, a first bearing and a nut

Abstract

The invention relates to a bearing assembly having a shaft, a first bearing and a nut, wherein the nut has a thread which is screwed onto a threaded region configured on the shaft, wherein a bearing seat configured on the shaft adjoins the threaded region, wherein an inner ring of the first bearing contacts the bearing seat, wherein the nut contacts the inner ring of the first bearing, wherein the inner ring of the first bearing is arranged spaced apart from the threaded region of the shaft, wherein a relief region of the thread cut out in the threaded region of the shaft is arranged in a partial region of the bearing seat adjoining the threaded region.

Description

Technical Field

[0001] The present invention relates to a support assembly having a shaft, a first bearing and a nut. Background Technology

[0002] It is generally known that shafts can be supported in a rotatable manner by bearings.

[0003] As the closest prior art, a speed reducer is known from DE 102 07 396 B4.

[0004] A support assembly is known from US 28 36 473 A.

[0005] A fastening bearing preload device is known from US 49 66 474 A.

[0006] A device for fixing a drive pinion is known from US 96 18 050 B2.

[0007] A multi-piece spacer element for adjusting bearing preload is known from US 2010 / 0 247 016 A1.

[0008] A self-aligned planetary gear transmission mechanism is known from US 29 36 655 A.

[0009] A bearing device for axles is known from DE 197 13 211 A1.

[0010] An axially adjustable support assembly is known from GB 20 27 134 A. Summary of the Invention

[0011] Therefore, the object of the present invention is to construct a support assembly with an extended service life.

[0012] According to the present invention, this objective is achieved by a support assembly according to the following features.

[0013] An important feature of the invention regarding the support assembly is that the support assembly has a shaft, a first bearing, and a nut, particularly a shaft nut.

[0014] The nut has threads, particularly internal threads, which are screwed onto a threaded area constructed on the shaft, the threaded area specifically having external threads.

[0015] The bearing housing constructed on the shaft is adjacent to the threaded area.

[0016] In this configuration, the inner ring of the first bearing contacts the bearing housing, and specifically, the inner ring of the first bearing is fitted onto the bearing housing.

[0017] The nut contacts the inner ring of the first bearing.

[0018] In this arrangement, the inner ring of the first bearing is spaced apart from the threaded area of ​​the shaft.

[0019] The retraction area (Auslaufbereich) of the thread cut in the threaded area of ​​the shaft is located in a portion of the bearing housing adjacent to the threaded area.

[0020] The advantage here is that the nut achieves axial fixation via a threaded connection and radial centering / alignment via a mating seat abutting against the retraction area. Because the retraction area, through the threaded region, extends into the bearing housing, the internal cylindrical mating seat constructed on the nut can be fitted onto the retraction area and thus centered in the radial direction. Therefore, axial and radial fixation is achieved when the nut is screwed onto the shaft, and no backlash is formed in either direction. Improved rotational accuracy is achieved in this way. The latter is particularly important, for example, in planetary gear transmission mechanisms.

[0021] In an advantageous design, the bearing housing is constructed with a precision-machined, particularly ground, cylindrical, especially externally cylindrical, surface.

[0022] In particular, the surface is interrupted only by the recessed portion of the retraction area. The advantage here is that the bearing housing can be manufactured with very high precision and the nut can be precisely centered on the internal cylindrical mating seat by means of this mating seat.

[0023] In an advantageous design, the nut presses against the inner ring of the first bearing. The advantage here is that the first bearing is preloaded, thus reducing bearing clearance.

[0024] In an advantageous design, the bearing housing covers a larger area than the inner ring of the first bearing in the axial direction, particularly in the direction of the shaft's rotation axis.

[0025] In particular, the bearing housing extends further in the axial direction than the contact area between the bearing housing and the inner ring of the first bearing. The advantage here is that the area of ​​the shaft machined with high precision not only has the axial width of the inner ring, but is also wider than the axial width of the inner ring.

[0026] In an advantageous design, the nut has a first internal cylindrical region adjacent to the nut's thread, particularly a mating seat, wherein this region contacts the bearing housing, particularly the retraction area, and is fitted and / or pressed against the bearing housing, particularly the retraction area. The advantage here is that the nut can be precisely centered on the shaft and therefore also oriented relative to the inner ring centered on the bearing housing.

[0027] In an advantageous design, the nut has a chamfered portion that wraps around the circumference on its axially oriented edge region. This has the advantage of simplifying the insertion of the nut when fitting it onto the shaft.

[0028] In an advantageous design, the maximum net inner diameter of the nut in its threaded region is less than or equal to the net inner diameter of the first internal cylindrical region adjacent to the nut thread, particularly the mating seat. The advantage here is that the nut thread does not require retraction within the mating seat region.

[0029] In a favorable design, the outer ring of the first bearing is housed within the housing.

[0030] The outer ring of the second bearing is housed within the housing. This has the advantage that the shaft is rotatably supported relative to the housing.

[0031] In a favorable design, the outer ring of the first bearing rests against the stepped portion of the housing.

[0032] The outer ring of the second bearing abuts against the stepped portion of the housing. An advantage here is that the two stepped portions are arranged in a mirror-symmetrical manner. Therefore, in the axial direction, the first stepped portion is upward, more precisely, radially inward, while the second stepped portion is downward, that is, radially outward.

[0033] Therefore, a radially constricted portion of the housing is provided axially between the two stepped portions. In this region between the two stepped portions, internal teeth may be constructed on the housing or on a gear ring connected to the housing in a manner that prevents relative rotation. The internal teeth mesh with a planetary gear supported on a pin, wherein the pin is inserted into the shaft or constructed as a single piece, particularly integrally.

[0034] In an advantageous design, the housing is constructed as a single piece, wherein internal teeth are formed on the housing. The advantage here is that it allows for simple manufacturing.

[0035] In an advantageous design, the housing is constructed in multiple parts, wherein the housing has a toothed ring with internal teeth. The advantage here is that the toothed ring can be made of a different material than the housing, which is preferably made of gray cast iron, particularly by ADI.

[0036] In a favorable design, the inner ring of the second bearing is fitted onto the shaft.

[0037] In particular, the inner ring of the second bearing abuts against a stepped portion constructed on the shaft. The advantage here is that the second bearing is accommodated on the shaft.

[0038] In an advantageous design, a stepped portion constructed on the housing is arranged axially between the first and second bearings, with the outer rings of both bearings abutting against the stepped portion.

[0039] The second bearing is arranged axially between the first bearing and a stepped portion constructed on the shaft, with the inner ring of the second bearing abutting against the stepped portion. An advantage here is that the housing can be easily manufactured.

[0040] In an advantageous design, the first bearing is arranged axially between the nut and the second bearing. The advantage here is that the nut generates a closed-loop force flow through both bearings.

[0041] In an advantageous design, a first internal cylindrical region constructed on the nut is arranged axially between the nut's thread and the inner ring of the first bearing. The advantage here is that high-precision alignment can be achieved.

[0042] In an advantageous design, the bearing housing constructed on the shaft is arranged axially between the threaded area of ​​the shaft and the second bearing. The advantage here is that alignment can be achieved by means of the mating housing, thus improving the rotational accuracy of the shaft.

[0043] In an advantageous design, the shaft is a planet carrier, in which planetary gear pins are received and / or connected. The planetary gears are supported, in particular by means of bearings, especially needle roller bearings, mounted on and rotatably supported on the planetary gear pins.

[0044] In this design, the teeth of the planetary gear mesh with internal teeth on one hand, and with rotatably arranged components, particularly the teeth of the sun gear that serve as the sun gear teeth on the other. This has the advantage of achieving high rotational accuracy, especially in the case of a flange block output section on the output side. Therefore, the overall service life of the reducer, and especially the two bearings, is also extended.

[0045] In an advantageous design, the nut has a second internal cylindrical region adjacent to the nut's thread and positioned on the side of the nut's thread opposite to the first internal cylindrical region.

[0046] In particular, the second inner cylindrical region has a net inner diameter smaller than the minimum net inner diameter of the nut's thread and / or presses against the second outer cylindrical region of the shaft, which is adjacent to the threaded region of the shaft and has an outer diameter smaller than the maximum outer diameter of the threaded region of the shaft. The advantage here is that the nut is centered on both sides, and thus rotational accuracy is further improved.

[0047] This invention is not limited to the above-described combination of features. Those skilled in the art, particularly those seeking to achieve their intended purpose and / or by comparison with the prior art, will recognize other reasonable combinations of the above-described features and / or individual features described above and / or features described below and / or features in the accompanying drawings. Attached Figure Description

[0048] The present invention will now be described in detail with reference to the schematic diagram:

[0049] exist Figure 1 The support assembly according to the invention for a planetary gear transmission mechanism is shown in cross-section.

[0050] exist Figure 2 The corresponding oblique view is shown in the figure.

[0051] exist Figure 3 Enlarged to show Figure 1 The region denoted by B.

[0052] exist Figure 4 Enlarged to show Figure 1 The region denoted by C. Detailed Implementation

[0053] As shown in the figure, the support assembly has bearings 5 ​​and 7 for supporting the shaft, which are received in the housing component, specifically in the housing 6 having a gear ring. The shaft is constructed, for example, as a planet carrier 2 together with a second sidewall 4 of the planet carrier 2.

[0054] Here, the second sidewall 4 and the planet carrier 2 are connected in a manner that prevents relative rotation, and are constructed as a single part, that is, as one piece, in particular as an integral structure, or as two interconnected parts, in particular as a two-piece structure.

[0055] The corresponding planetary gear pin 3 is not only pressed into the hole of the planet carrier 2, but also into the hole of the second side wall 4.

[0056] The first bearing 7 is preloaded by means of a nut 1, specifically a shaft nut, screwed onto the external thread of the shaft. Here, the nut 1 presses the inner ring of the first bearing 7, which is fitted onto the shaft, specifically the planetary carrier 2, towards the second bearing 5 in the axial direction. This pulls the shaft in the opposite direction and thus presses the inner ring of the second bearing 5, fitted onto the shaft, specifically onto the second sidewall 4, towards the first bearing 7. The outer rings of both bearings 5 ​​and 7 are located on the shoulder of the housing 6. This creates a closed force flow that returns from the nut to the nut 1 via the planetary carrier 2, the second bearing 5, the housing 6, and the first bearing 7.

[0057] Therefore, the two bearings 5 ​​and 7 are preloaded by means of nut 1.

[0058] The two bearings 5 ​​and 7 are preferably constructed as radial thrust bearings.

[0059] A toothed ring with internal teeth is received in the housing 6, or the toothed ring is integrally constructed in the housing 6 by forming internal teeth on the inner side of the housing 6, particularly axially, between two shoulders.

[0060] The planetary gear, which is rotatably supported on the planetary gear pin 3, meshes with the internal teeth on one side and with the teeth of the sun gear, which is rotatably supported on the other side.

[0061] The sun gear and planetary gears are not shown in the attached diagram.

[0062] Nut 1 is particularly advantageous when the planetary gear transmission stage has a flanged output section. This is because the outer diameter of the planet carrier 2 on the output side is very large in this case. In particular, the radial range covered by nut 1 with respect to the rotation axis of planet carrier 2 includes the radial range covered by the inner ring of the first bearing 7, or the two radial ranges at least overlap.

[0063] In the support assembly according to the invention, the shaft 2, particularly the planetary carrier 2, has a finished bearing housing 30 on which the inner ring of the first bearing 7 is arranged. However, the finished bearing housing 30 extends in the axial direction longer than the axial region required by the inner ring of the first bearing 7.

[0064] The threaded area 32 of the shaft, especially the external threaded area, is adjacent to the bearing housing 30 of the shaft, and the nut 1 is screwed onto the external threaded area with its thread, especially the internal thread.

[0065] The threaded region 32 is preferably constructed as an external threaded region.

[0066] When manufacturing the threaded region 32, the tool, particularly the cutting tool, moves in the axial direction, especially in the direction of the rotation axis of shaft 2, and the tool cuts to create the thread. Although the finished, particularly smooth, cylindrical region of bearing housing 30 is adjacent to the end of the threaded region 32, a retraction region 31 is created as the tool moves radially away. This is because as the tool moves radially away, the shaft still rotates about its rotation axis in the circumferential direction, resulting in a retraction thread groove / thread line in the retraction region 31. Here, the radial depth of the thread groove, i.e., the helical cut of the threaded region 32, decreases as the axial distance from the threaded region 32 increases. Therefore, the minimum radial distance of the thread groove in the retraction region 31 is a strictly monotonically increasing function of the axial distance from the threaded region 32 until this minimum radial distance reaches the outer radius of bearing housing 30. The inner ring of bearing 7 is arranged axially spaced from the threaded region 32 and the retraction region 31. The retraction area 31 is surrounded by a bearing housing 30 that is otherwise finished, because the bearing housing 30 extends longer axially than the inner ring of the bearing 7 and has been made before the thread cutting area 32.

[0067] Although the shaft blank is only finished in the area of ​​bearing housing 30, particularly in the area of ​​the subsequently manufactured relief area 31, the blank is only rough-machined in the area of ​​the subsequently manufactured threaded area 32, specifically by turning. After manufacturing the threaded area 32, the maximum radial distance in the threaded area 32 is less than half the outer diameter of the bearing housing 30. This is because the tooth crests between the recesses of the thread grooves are also machined during the manufacturing of the threaded area 32.

[0068] Nut 1 has an internal thread, which is used to screw nut 1 onto the threaded area 32 of the shaft. Here, nut 1 has a finely machined internal cylindrical area connected to its internal thread area, which is pushed when nut 1 is screwed onto bearing housing 30, in particular retraction area 31, and thus causes radial alignment of nut 1 relative to the shaft, in particular planetary carrier 2.

[0069] Furthermore, the nut has a chamfered portion that circumferentially surrounds its end region facing the first bearing 7. Therefore, it is easy to insert when fitting onto the shaft.

[0070] According to the present invention, there is no relief groove / countercut groove connected to the threaded area 32 on the shaft, but the relief area 31 is connected to the threaded area 32.

[0071] In another embodiment of the invention, the nut 1 has an internal cylindrical region, particularly a mating seat, not only at its end region facing the first bearing 7, but also at its end region away from the first bearing 7. Thus, the two internal cylindrical regions axially abut the threads of the nut 1 on both sides, wherein the net inner diameter of the second internal cylindrical region, i.e., the internal cylindrical region arranged away from the first bearing, is smaller than the net inner diameter of the first internal cylindrical region. However, in particular, the net inner diameter of the second internal cylindrical region is also smaller than the minimum net inner diameter of the threads of the nut 1, and also has a retraction area required for the cutting tool during thread manufacturing. The shaft has a corresponding external cylindrical region abutting the thread region 32 on the side away from the retraction area 31, and in particular, does not have a retraction area. Therefore, the nut can be centered on the shaft radially and axially without clearance using the mating seats on both sides, and further improved rotational accuracy can be achieved. This improves the service life of the planetary gear transmission mechanism, particularly in embodiments where the shaft is a planetary carrier.

[0072] In other embodiments of the invention, the planet carrier 2 is constructed with a single-sided wall and is therefore supported in the housing 6 via two bearings 5 ​​and 7. Here, the planetary gear pins are preferably inserted into the corresponding holes in the planet carrier 2 only on one side.

[0073] List of reference numerals in the attached diagram:

[0074] 1 nut

[0075] 2 Planetary Carrier

[0076] 3 Planetary gear pins

[0077] 4. Second sidewall of the planetary carrier

[0078] 5 bearings

[0079] 6. Housing with gear ring

[0080] 7 bearings

[0081] 30 Bearing Housing

[0082] 31 Retraction Area

[0083] 32. Threaded area.

Claims

1. A support assembly having a shaft, a first bearing, and a nut, the nut being a shaft nut. The nut has threads, which are internal threads, and these threads are screwed onto a threaded area constructed on the shaft, the threaded area on the shaft having external threads. Its features are, The bearing housing constructed on the shaft is adjacent to the threaded area. The inner ring of the first bearing contacts the bearing housing, and the inner ring of the first bearing is fitted onto the bearing housing. The nut contacts the inner ring of the first bearing. The inner ring of the first bearing is arranged separately from the threaded area of ​​the shaft. The retraction area of ​​the thread cut in the threaded region of the shaft is arranged in a portion of the bearing housing adjacent to the threaded region. The nut has a first internal cylindrical region adjacent to the nut's thread, and the first internal cylindrical region contacts the retraction area. The nut has a second internal cylindrical region adjacent to the thread of the nut and arranged on the side of the thread of the nut opposite to the first internal cylindrical region.

2. The support assembly according to claim 1, Its features are, The bearing housing is constructed with a precision-machined external cylindrical surface. The surface is interrupted only by the recessed portion of the retraction area.

3. The support assembly of claim 2, wherein, The surface of the outer cylindrical shape is machined by grinding.

4. The support assembly according to any one of claims 1 to 3, Its features are, The nut is pressed onto the inner ring of the first bearing.

5. The support assembly according to any one of claims 1 to 3, Its features are, The bearing housing covers a larger area than the inner ring of the first bearing in the axial direction, that is, in the direction of the shaft's rotation axis. The bearing housing extends further in the axial direction than the contact area between the bearing housing and the inner ring of the first bearing.

6. The support assembly according to any one of claims 1 to 3, Its features are, The first internal cylindrical region is fitted and / or pressed onto the retraction region by the mating seat.

7. The support assembly according to any one of claims 1 to 3, Its features are, The nut has a chamfered portion that surrounds the circumference on its axially oriented edge region.

8. The support assembly according to any one of claims 1 to 3, Its features are, The maximum net inner diameter of the nut in its threaded region is less than or equal to the net inner diameter of the first inner cylindrical region adjacent to the nut thread.

9. The support assembly according to any one of claims 1 to 3, Its features are, The outer ring of the first bearing is housed within the housing. The outer ring of the second bearing is housed within the housing. And / or, The outer ring of the first bearing rests against the stepped portion of the housing. The outer ring of the second bearing rests against the stepped portion of the housing.

10. The support assembly according to claim 9, Its features are, The shell is constructed as a single piece, and internal teeth are formed on the shell. or, The shell is constructed in multiple parts, wherein the shell has a toothed ring with internal teeth.

11. The support assembly according to claim 9, Its features are, The inner ring of the second bearing is fitted onto the shaft. The inner ring of the second bearing abuts against a stepped portion constructed on the shaft.

12. The support assembly according to claim 11, Its features are, The stepped portion constructed on the housing, on which the outer rings of the two bearings abut, is arranged axially between the first and second bearings. The second bearing is arranged in the axial direction between the first bearing and the stepped portion on the shaft where the inner ring of the second bearing abuts.

13. The support assembly according to claim 9, Its features are, The first bearing is arranged axially between the nut and the second bearing.

14. The support assembly according to claim 13, Its features are, The first internal cylindrical region constructed on the nut is arranged axially between the thread of the nut and the inner ring of the first bearing. And / or, The bearing housing constructed on the shaft is arranged in the axial direction between the threaded area of ​​the shaft and the second bearing.

15. The support assembly according to claim 10, Its features are, The shaft is a planet carrier, in which planetary gear pins are received and / or connected, and planetary gears are mounted on and rotatably supported on the planetary gear pins. The teeth of the planetary gear mesh with the internal teeth on one hand, and with the teeth of a component arranged in a rotatable manner that serve as the sun gear teeth on the other hand.

16. The support assembly of claim 15, wherein, The planetary gear is mounted on the planetary gear pin by means of a bearing mounted on the planetary gear pin.

17. The support assembly according to claim 16, characterized in that, The bearing mounted on the planetary gear pin is a needle roller bearing.

18. The support assembly according to claim 15, characterized in that, The component in question is the sun gear.

19. The support assembly according to any one of claims 1 to 3, Its features are, The net inner diameter of the second inner cylindrical region is smaller than the minimum net inner diameter of the nut's thread and / or the second inner cylindrical region is pressed against the second outer cylindrical region of the shaft, which is adjacent to the threaded region of the shaft, and the outer diameter of the second outer cylindrical region is smaller than the maximum outer diameter of the threaded region of the shaft.

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