Gear, assembly, and transmission

Abstract

The present invention relates to a gear (16) for a gear transmission, comprising: a rotation axis (18) having an axial direction (20) and a circumferential direction (22); a plurality of gear portions (24, 26, 50) configured as individual components and arranged adjacent to each other along the axial direction (20); each of the gear portions (24, 26, 50) having a gear ring (28) arranged circumferentially around the rotation axis (18); wherein the gear portions (24, 26, 50) can each reach a coupled state by rotating relative to each other along the circumferential direction (22), wherein the gear portions (24, 26, 50) are fixedly connected to each other along the axial direction (20), and wherein the gear portions (24, 26, 50) are arranged without bias relative to each other along the circumferential direction (22) in the coupled state. The invention also relates to an assembly (10) having such a gear and a gear transmission having such a gear.

Description

Technical Field

[0001] The present invention relates to a gear, an assembly having such a gear, and a gear transmission. Background Technology

[0002] Transmissions with plastic gears are used in numerous technical fields, such as in adjustable drives in motor vehicles, drive systems in electric bicycles, and in industrial applications. In particular, the planetary gears in planetary gear transmissions used therein are made of plastic.

[0003] Currently, most plastic gears are manufactured using plastic injection molding. To secure the plastic gear to a central element, such as a shaft or bearing, the central element is typically embedded in an injection mold and then overmolded with the plastic material from which the gear is to be manufactured. During the cooling of the plastic, shrinkage stress is often generated within the gear, and this shrinkage stress can consume a significant portion of the plastic's usable strength potential. This results in a short lifespan for such gears.

[0004] Furthermore, a risk inherent in the aforementioned manufacturing method is that the central component embedded in the injection mold may be damaged during overmolding. Therefore, during the overmolding of the rolling bearing, especially at high mold temperatures, lubricant may leak from the rolling bearing. This leaked lubricant can then contaminate the injection mold or the plastic.

[0005] Furthermore, multi-part gear arrangements with a primary gear and a secondary gear are known from the prior art. These arrangements can be manufactured independently of the central element and then mounted on it. In the mounted state, the primary gear and the secondary gear are spring-loaded relative to each other about the axis of rotation in the circumferential direction. This arrangement is used to eliminate backlash between the meshing gears. Relevant prior art documents include: DE102011122138A1, US2013 / 0213168A1, US2018 / 0017151A1, and US2013 / 0112027A1.

[0006] This arrangement is primarily used for gears made of metals, such as powder metallurgy. The disadvantages of this arrangement sometimes lie in increased friction and therefore increased wear during gear engagement, as well as increased manufacturing costs, especially installation costs. Therefore, the fastening of this gear arrangement to the central element must be achieved through additional manufacturing and / or installation steps. In particular, a separate axial fixation is required in known examples. Summary of the Invention

[0007] Therefore, the objective of this invention is to provide a gear arrangement that has a long service life and is easy to manufacture.

[0008] According to the present invention, this object is achieved by a gear having the features of claim 1, a component having the features of claim 13, and a gear transmission having the features of claim 14.

[0009] Advantageous designs and improvements of the invention are given in the dependent claims.

[0010] A gear, particularly a cylindrical gear, for a gear transmission according to the invention includes a rotation axis having an axial direction and a circumferential direction. The term "axial direction" herein and hereinafter preferably refers to two opposite directions along the rotation axis. Correspondingly, the term "circumferential direction" herein and hereinafter can be understood as two opposite directions about the rotation axis. The axial direction is preferably arranged perpendicular to the circumferential direction. Unless otherwise stated, the terms "axial" and "radial" as used herein and hereinafter also refer to the rotation axis.

[0011] The gear according to the invention comprises a plurality of gear portions configured as individual components and arranged adjacent to each other in the axial direction, wherein each gear portion has a gear ring arranged circumferentially about an axis of rotation. Preferably, the gear ring is arranged circumferentially about the axis of rotation. The gear portions are preferably arranged coaxially with the axis of rotation. The gear portions can each reach a coupled state by rotating relative to each other in the circumferential direction, in which the gear portions are fixedly connected to each other in the axial direction. Therefore, each of the gear portions preferably must rotate relative to its corresponding adjacent gear portion in order to reach a coupled state from a decoupled state. In the coupled state, the gear portions can be connected to each other, in particular, by form-fitting manner. Through the arrangement of being fixedly connected to each other in the axial direction, axial force can preferably be transmitted between the gear portions in the coupled state.

[0012] According to the invention, the gear portions are arranged circumferentially without bias relative to each other in the coupled state. In particular, the gears do not have biasing elements, such as spring elements, which would generate biasing forces between the gear portions. Thus, gears with low wear and easy manufacturing can be provided.

[0013] Preferably, the gear portions are rotatably arranged relative to each other in the circumferential direction in the coupled state. When engaged with a mating gear, the gear portion can thereby align with the mating gear, allowing the gear to compensate for tolerances, such as shaft misalignment or deformation.

[0014] Each gear portion in the gear assembly may have a ring gear with multiple teeth, each tooth having a tooth end face arranged perpendicular to the axis of rotation. Gear portions adjacent to each other in the coupled state may be arranged relative to each other such that their tooth end faces are arranged opposite each other in the axial direction. Preferably, none of the tooth end faces are arranged relative to the tooth grooves arranged between the teeth. This arrangement preferably corresponds to the arrangement of the tooth end faces relative to each other when the gear engages with the mating gear. Therefore, the gear portions can be fixedly connected to each other in the axial direction when engaged with the mating gear. Preferably, the tooth end faces of adjacent gear portions in the gear assembly abut against each other and, particularly preferably, are arranged without offset relative to each other in the circumferential direction. The gear preferably has a continuous tooth profile in the axial direction.

[0015] In a preferred embodiment of the invention, the gear portion is configured as an injection-molded portion, preferably as a plastic injection-molded portion. Preferably, each of the gear portions is configured as a plastic injection-molded portion. Thus, the gear can be mass-produced inexpensively and with high precision. By constructing a gear composed of multiple gear portions, the gear can be easily mounted on a central element, such as a bearing or shaft.

[0016] Gear components have the same and / or different helix angles. Therefore, different types of teeth can be achieved in a simple way. If all gear components have the same helix angle, the gear can therefore be constructed using either spur or helical machining. Herringbone teeth can be achieved simply using two gear components with equal but different helix angles.

[0017] Preferably, at least one gear portion has at least one first coupling element. Particularly preferably, each gear portion has at least one first coupling element. The at least one first coupling element may be arranged on a first end face of the at least one gear portion, preferably perpendicular to the axis of rotation. Preferably, the at least one first coupling element is configured to protrude beyond the first end face in the axial direction. The at least one gear portion may include a plurality, preferably three, of the at least one first coupling element, which may be evenly distributed in the circumferential direction.

[0018] Particularly preferably, at least one gear portion has at least one second coupling element that can be coupled to at least one first coupling element. Therefore, a coupling state can preferably be established through the interaction of at least one first coupling element and at least one second coupling element. Preferably, each gear portion has at least one second coupling element that can be coupled to at least one first coupling element. The at least one second coupling element may be arranged on a first end face of at least one gear portion. Preferably, the at least one second coupling element is configured as a recess that is retracted axially relative to the first end face. At least one gear portion may include a plurality, preferably three, of the at least one second coupling element, which may be evenly distributed circumferentially.

[0019] Preferably, at least one first coupling element and at least one second coupling element can be coupled to each other, particularly preferably by rotating the corresponding gear portions relative to each other in a circumferential direction. At least one first coupling element and at least one second coupling element may each have an undercut, wherein, preferably, the undercut of at least one first coupling element can engage with the undercut of at least one second coupling element. At least one first coupling element and at least one second coupling element may together constitute a coupling unit in the form of a bayonet connector.

[0020] In a gear portion arranged adjacent to two gear portions in a gear portion, at least one first coupling element and / or at least one second coupling element may be arranged in the manner described above on the first end face of the respective gear portion and on the second end face of the gear portion arranged opposite to the first end face in the axial direction.

[0021] At least one of the gear portions preferably has an inner sheath surface radially arranged inside the gear ring. Particularly preferably, each of the gear portions has an inner sheath surface radially arranged inside the gear ring. At least one second coupling element may be configured as a recess in the inner sheath surface.

[0022] In a preferred embodiment, at least one gear portion has a shoulder that projects radially inward beyond the surface of the inner sheath and rotates at least segmentally about the axis of rotation. The shoulder can rotate completely about the axis of rotation. The shoulder allows axial forces to be transmitted from the gear to the central element and vice versa. Preferably, the shoulder is located on an axial end of at least one gear portion, which is particularly preferably arranged axially opposite to a first end face.

[0023] The inner sheath surface may have driving teeth for transmitting torque acting about the axis of rotation, the driving teeth having at least one driving tooth. Therefore, torque can be transmitted from at least one gear portion, for example, to the central element. Preferably, the at least one driving tooth is arranged parallel to the axial direction. In an alternative embodiment of the inner sheath surface, the inner sheath surface may not have driving teeth for transmitting torque acting about the axis of rotation. Preferably, a gear portion having driving teeth is arranged adjacent to such a gear portion, the inner sheath surface of which has no driving teeth. Thus, rotatability can be achieved between the gear portion without an inner sheath surface and the gear portion with an inner sheath surface. Therefore, the corresponding gear portions can achieve a coupled state.

[0024] In a preferred embodiment of the invention, the gear has exactly two or exactly three gear portions. In this configuration, the gear can be installed particularly easily.

[0025] In an improved embodiment of the invention, two of the gear portions are identical. Particularly preferably, the gear has exactly two gear portions, wherein these gear portions are identical.

[0026] An assembly according to the invention includes the aforementioned gear and a central element radially arranged inside the gear ring, wherein the central element is configured as a shaft or a bearing. The bearing may be, in particular, a rolling bearing. The central element is preferably configured to abut against the surface of an inner sheath. The fit between the inner sheath surface and the central element may be a transition fit or a press fit.

[0027] A gear transmission according to the invention includes at least one of the aforementioned gears and / or the aforementioned components, and a mating gear meshing with the at least one gear, wherein the mating gear engages with each of the gear portions. Due to the engaging mating gears, the gear portions of at least one gear can be rotatable relative to each other in the circumferential direction, at most within the range of tooth backlash. Therefore, disengagement of the coupling state caused by rotation of the gear portions relative to each other can be prevented.

[0028] In one possible implementation, the gear transmission is configured as a planetary gear transmission having at least one planetary gear, wherein the at least one planetary gear is formed by at least one gear.

[0029] As one application, an adjustable drive system for a motor vehicle with the aforementioned gear transmission can be envisioned. As another application, a drive system for an electric bicycle or electric mini-motorcycle with the aforementioned gear transmission can be envisioned. Attached Figure Description

[0030] Embodiments of the present invention are described below with reference to the accompanying drawings. In the drawings:

[0031] Figure 1 An exploded view of a first embodiment of the component is shown;

[0032] Figure 2 It shows Figure 1 A perspective view of the embodiment shown;

[0033] Figure 3 It shows Figure 1 A perspective view of the gear portion of the embodiment shown;

[0034] Figure 4 An exploded view of a second embodiment of the component is shown;

[0035] Figure 5 It shows Figure 4 A perspective view of the embodiment shown;

[0036] Figure 6 An exploded view of a third embodiment of the component is shown;

[0037] Figure 7 It shows Figure 6 A perspective view of the embodiment shown. Detailed Implementation

[0038] Figures 1 to 7 Various embodiments are shown. The same reference numerals are used for identical and functionally identical parts. For clarity, not all reference numerals are used in every figure.

[0039] Figure 1 and Figure 2 A first embodiment of component 10 is shown, and the arrangement is described in detail based on this first embodiment. Component 10 includes a central element 14 configured as a bearing 12, preferably configured as a rolling bearing, and a gear 16 configured as a cylindrical gear. Gear 16 includes a rotation axis 18 having an axial direction 20 and a circumferential direction 22 arranged perpendicular to the axial direction 20.

[0040] Figure 1 The gear 16 shown includes a first gear portion 24 and a second gear portion 26, which are configured as separate components and arranged adjacent to each other in the axial direction 20. Each of the gear portions 24 and 26 has a gear ring 28 arranged circumferentially about a rotation axis 18 in the circumferential direction 22. The gear portions 24 and 26 are preferably arranged coaxially with the rotation axis 18. The gear portions 24 and 26 can be coupled by rotating relative to each other in the circumferential direction 22, in which the gear portions 24 and 26 are fixedly connected to each other in the axial direction 20, so that axial force can be transmitted between the gear portions 24 and 26. Although in Figure 1An exploded view of component 10 is shown, but gear parts 24 and 26 are not shown. Figure 2 The figure shows the state under coupling.

[0041] Especially Figure 3 As shown, each of the gear portions 24 and 26 has three first coupling elements 30 and three second coupling elements 32 that can be coupled to the first coupling elements 30 to establish a coupled state of the gear portions 24 and 26. Each of the gear portions 24 and 26 has a first end face 34 arranged perpendicular to the axis of rotation 18. The first coupling elements 30 and the second coupling elements 32 are respectively evenly distributed along the circumferential direction 22 on the first end face 34 of the first gear portion 24 and the first end face 34 of the second gear portion 26.

[0042] The first coupling element 30 is configured to protrude beyond the first end face 34 along the axial direction 20. The second coupling element 32 is configured as a recess that retracts relative to the first end face 34 along the axial direction 20. Each of the first coupling element 30 and each of the second coupling element 32 has an undercut portion 36. Here, the undercut portions 36 of the first coupling element 30 and the second coupling element 32 can be engaged with each other by rotating the gear portions 24, 26 relative to each other in the circumferential direction 22. Therefore, the first coupling element 30 and the second coupling element 32 constitute a coupling unit in the form of a bayonet connector. Thus, in the coupled state, the gear portions 24, 26 are connected to each other, particularly in a form-fit manner.

[0043] Especially in Figure 3 As can be seen, gear portions 24 and 26, in the coupled state, are rotatably arranged relative to each other in the circumferential direction 22, provided that the undercut 36 allows. When engaging with the mating gear of gear 16, gear portions 24 and 26 can thereby align with the mating gear, allowing gear 16 to compensate for tolerances, such as shaft misalignment or deformation. Figure 3 It can also be seen that in the first embodiment, the first gear portion 24 and the second gear portion 26 are identical. For example... Figure 1 As shown, the first gear portion 24 and the second gear portion 26 have the same helix angle 37.

[0044] Especially refer to Figure 1 It is understood that gear portions 24 and 26 are arranged relative to each other without bias in the circumferential direction 22 in the coupled state. In particular, gear 16 has no biasing element, such as a spring element, which would generate a biasing force between gear portions 24 and 26.

[0045] like Figure 1 and Figure 3As shown, the gear ring 28 of each of the gear portions 24 and 26 has a plurality of teeth 38, each of which has a tooth end face 40 arranged perpendicular to the axis of rotation 18. In the coupled state, the adjacent gear portions 24 and 26 can be arranged relative to each other such that their tooth end faces 40 are arranged opposite each other in the axial direction 20. In particular, none of the tooth end faces 40 are arranged relative to the tooth grooves 42 arranged between the teeth 38. Therefore, the gear portions 24 and 26 can be fixedly connected to each other in the axial direction 20 when engaged with a mating gear. As particularly Figure 2 As shown, the tooth end faces 40 of the adjacent gear portions 24 and 26 abut against each other and are arranged in the circumferential direction 22 without offset from each other.

[0046] Figure 1 and Figure 3 Further shown, gear portions 24 and 26 each have an inner sheath surface 44 radially arranged inside the gear ring 28. Here, the central element 14 is configured to abut against the inner sheath surface 44. The second coupling elements 32 are each configured as a recess in the inner sheath surface 44.

[0047] The first gear portion 24 and the second gear portion 26 each have a shoulder 46 that protrudes radially inward beyond the inner sheath surface 44 and rotates completely around the axis of rotation 18. The center element 14 is correspondingly arranged to abut against the shoulder 46. Thus, axial force can be transmitted from the gear 16 to the center element 14 and vice versa via the shoulder 46. The shoulder 46 is correspondingly arranged on the axial end 48 of the first gear portion 24 or the second gear portion 26, wherein the axial end 48 is correspondingly arranged opposite the first end face 34 along the axial direction 20.

[0048] Given Figure 4 and Figure 5 The second embodiment shown below will be substantially described in conjunction with the previous one. Figure 1 and Figure 2 The difference from the first embodiment.

[0049] Figure 4 As shown, the central element 14 of component 10 includes two bearings 12. Regarding the gear 16 of the second embodiment, the first gear portion 24 and the second gear portion 26 are also identically configured. Furthermore, the gear 16 has a third gear portion 50 configured as a separate component, which is arranged axially 20 between the first gear portion 24 and the second gear portion 26. Here, the third gear portion 50 preferably does not have a shoulder 46.

[0050] The third gear portion 50 has a first end face 34 and a second end face 52 arranged opposite to the first end face 34 along the axial direction 20 and perpendicular to the axis of rotation 18. Here, the first end face 34 of the third gear portion 50 is arranged adjacent to the first end face 34 of the first gear portion 24. The second end face 52 of the third gear portion 50 is arranged adjacent to the first end face 34 of the second gear portion 24. Corresponding to the arrangement on the first end face 34 of the first gear portion 24 and the second gear portion 26, the third gear portion 50 has three first coupling elements 30 and three second coupling elements 32 that can be coupled to the first coupling elements 30 on each of its end faces 34 and 52. The first coupling elements 30 and the second coupling elements 32 are each evenly distributed along the circumferential direction 22. Therefore, the third gear portion 50 can achieve a coupling state with the first gear portion 24 and the second gear portion 26 respectively by rotating relative to the first gear portion 24 and the second gear portion 26 along the circumferential direction 22 in the manner described above.

[0051] like Figure 4 and Figure 5 As further shown, the third gear portion 50 is machined as a spur gear and therefore has a helix angle of 0°. Thus, the helix angle of the third gear portion 50 differs from the helix angle 37 of the first gear portion 24 and the second gear portion 26.

[0052] Given Figure 6 and Figure 7 The third embodiment shown will also be described below in essentially the same way as the third embodiment. Figure 1 and Figure 2 The difference from the first embodiment.

[0053] Especially Figure 6 As shown, in the assembly 10 of the third embodiment, the central element 14 is configured as a shaft 54. The first gear portion 24 and the second gear portion 26 are configured separately. Therefore, the first gear portion 24 is wider than the second gear portion 26 in the axial direction 20. Furthermore, the inner sheath surface 44 of the first gear portion 24 has driving teeth for transmitting torque acting around the rotation axis 18, the driving teeth having four driving teeth 56. The driving teeth 56 are parallel to the axial direction 20 and arranged to engage in the recess 58 of the shaft 54. The inner sheath surface 44 of the second gear portion 26 adjacent to the first gear portion 24 does not have driving teeth, which will transmit torque between the central element 14 and the second gear portion 26. Thus, the second gear portion 26 can rotate relative to the first gear portion 24 in the circumferential direction 22, so that the first gear portion 24 and the second gear portion 26 can reach a coupled state. Therefore, the gear 16 of the third embodiment can be fixed radially and axially to the shaft 54.

[0054] The corresponding first gear portion 24 and the corresponding second gear portion 26 of the illustrated embodiment, as well as the third gear portion 50 of the second embodiment, are preferably configured as plastic injection molded portions.

[0055] List of reference numerals in the attached diagram:

[0056] 10 components

[0057] 12 bearings

[0058] 14. Central Components

[0059] 16 gears

[0060] 18. Axis of rotation

[0061] 20 Axial direction

[0062] 22 Circumferential direction

[0063] 24 First Gear Section

[0064] 26 Second Gear Section

[0065] 28 Gear Ring

[0066] 30 First coupling element

[0067] 32 Second coupling element

[0068] 34 First end face

[0069] 36. Undercut

[0070] 37 helix angle

[0071] 38 teeth

[0072] 40 Tooth end face

[0073] 42 tooth grooves

[0074] 44 Inner sheath surface

[0075] 46. ​​Shoulders

[0076] 48 Axial end

[0077] 50 Third Gear Section

[0078] 52 Second end face

[0079] 54 axes

[0080] 56 Drives the gear

[0081] 58. Depression

Claims

1. A gear (16), particularly a cylindrical gear, for use in a gear transmission, comprising: A rotation axis (18) having an axial direction (20) and a circumferential direction (22), and multiple gear portions (24, 26, 50) configured as individual components and arranged adjacent to each other along the axial direction (20). Each of the gear portions (24, 26, 50) has a gear ring (28) arranged circumferentially around the axis of rotation (18). Furthermore, the gear portions (24, 26, 50) can each achieve a coupled state by rotating relative to each other along the circumferential direction (22), in which the gear portions (24, 26, 50) are fixedly connected to each other along the axial direction (20), characterized in that the gear portions (24, 26, 50) are arranged relative to each other without bias along the circumferential direction (22) in the coupled state.

2. The gear according to claim 1, characterized in that, The gear portions (24, 26, 50) are each rotatably arranged relative to each other along the circumferential direction (22) in the coupled state.

3. The gear according to any one of the preceding claims, characterized in that, Each of the gear portions (24, 26, 50) has a gear ring (28) having a plurality of teeth (38), each of the plurality of teeth (38) having a tooth end face (40) arranged perpendicular to the axis of rotation (18), wherein the gear portions of the gear portions (24, 26, 50) that are adjacent to each other in the coupled state can each be arranged relative to each other such that their tooth end faces (40) are arranged relative to each other along the axial direction (20).

4. The gear according to any one of the preceding claims, characterized in that, The gear portions (24, 26, 50) are configured as injection-molded portions, preferably as plastic injection-molded portions.

5. The gear according to any one of the preceding claims, characterized in that, The gear portions (24, 26, 50) have the same and / or different helix angles (37).

6. The gear according to any one of the preceding claims, characterized in that, At least one of the gear portions (24, 26, 50) has at least one first coupling element (30).

7. The gear according to claim 6, characterized in that, At least one of the gear portions (24, 26, 50) has at least one second coupling element (32) that can be coupled to the at least one first coupling element (30).

8. The gear according to any one of the preceding claims, characterized in that, At least one of the gear portions (24, 26, 50) has an inner sheath surface (44) radially arranged inside the gear ring (28).

9. The gear according to claim 8, characterized in that, The at least one gear portion (24, 26) has a shoulder (46) that protrudes radially inward beyond the inner sheath surface (44) and rotates at least segmentally around the axis of rotation (18).

10. The gear according to any one of claims 8 to 9, characterized in that, The inner sheath surface (44) has driving teeth for transmitting torque acting around the rotation axis (18), the driving teeth having at least one driving tooth (56).

11. The gear according to any one of the preceding claims, characterized in that, The gear (16) has exactly two or exactly three of the gear portions (24, 26, 50).

12. The gear according to any one of the preceding claims, characterized in that, Two of the gear sections (24, 26, 50) have the same construction.

13. A component (10) having a gear (16) according to any one of the preceding claims and a central element (14) radially arranged inside a gear ring (28), wherein, The central element (14) is configured as a shaft (54) or a bearing (12).

14. A gear transmission having at least one gear (16) according to any one of claims 1 to 12 and / or an assembly (10) according to claim 13 and a mating gear meshing with said at least one gear (16), wherein, The mating gear engages with each of the gear portions (24, 26, 50).

15. The gear transmission according to claim 14, characterized in that, The gear transmission is configured as a planetary gear transmission having at least one planetary gear, wherein the at least one planetary gear is formed by the at least one gear (16).

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