DRIVE ASSEMBLY

Description

State of the art

[0001] The present invention relates to a drive arrangement, a vehicle comprising the drive arrangement and a method for assembling a drive arrangement.

[0002] Drive arrangements with drive units held between two walls, for example, a vehicle frame, are known. The drive unit is bolted to the two opposing walls. Typically, a gap between the drive unit and one of the walls must be bridged. To achieve this, a retaining plate can be provided on the drive unit, which is elastically deformed to bridge the gap. However, this can have an adverse effect on the mechanical load and the sealing of the drive arrangement. A prior art drive arrangement is disclosed in DE 10 2017 201617 A1, wherein a mounting for a drive unit has a tolerance compensation element in the form of a sliding bearing, which allows movement of a screw of the mounting along the longitudinal axis of the screw. When the screw is tightened, no radial expansion of the tolerance compensation element occurs. Disclosure of the invention

[0003] In contrast, the drive arrangement according to the invention with the features of claim 1 is characterized by the fact that a load-bearing advantageous mounting of a drive unit can be provided within a frame interface in a simple manner. This is achieved by a drive arrangement comprising a drive unit and a frame interface, wherein the drive unit is arranged at least partially between a first wall and a second wall of the frame interface. Furthermore, the drive arrangement comprises a first mounting and a second mounting. The first mounting holds the drive unit on the first wall of the frame interface, and the second mounting holds the drive unit on the second wall of the frame interface. The first mounting includes a screw and a sleeve-shaped tolerance compensation element.The tolerance compensation element is located at least partially within a wall opening in the first wall and rests against the drive unit. The tolerance compensation element is screwed to the drive unit. Specifically, the screw projects through the tolerance compensation element, in particular such that the tolerance compensation element is clamped between the drive unit and the screw head. The tolerance compensation element is designed to expand radially upon tightening, allowing it to bear at least partially against the inside of the wall opening when the screw is tightened to a predefined torque.

[0004] In other words, the drive unit is attached to the first wall using the first bracket by means of the tolerance compensation element deforming under the screw tension, causing it to expand radially until a frictional connection is established by pressing it against the inside of the wall opening. This frictional connection, i.e., the contact of the expanded part of the tolerance compensation element against the inside of the wall opening, is specifically a frictional connection in the axial direction, i.e., along the screw axis. Additionally, radial movement is restricted because the expanded tolerance compensation element rests against the entire circumference of the wall opening. Thus, the drive unit is reliably and precisely positioned and indirectly attached to the first wall by means of the tolerance compensation element.

[0005] To enable the specific radial deformability of the tolerance compensation element, it can be designed in a variety of ways. For example, the tolerance compensation element can have a special geometry and / or special incorporated structural features, such as defined slots or grooves, which, when tightened, cause the radial expansion of the tolerance compensation element. Alternatively, a uniformly shaped sleeve, for example, at least partially cylindrical, would also be possible, which deforms uncontrollably when tightened, whereby the sleeve can only deform radially outwards, for example, due to the screw located inside.

[0006] Preferably, the radial widening results from an axial compression or shortening of the tolerance compensation element, in particular which can be brought about by screwing it together using the screw.

[0007] In particular, the radial expansion takes the form of a plastic deformation of the tolerance compensation element.

[0008] The tolerance compensation element is particularly preferably designed as a one-piece component.

[0009] Preferably, a gap existing between the drive unit and the first wall of the frame interface, which may result, for example, from manufacturing-related differences in the dimensions of the drive unit and an interior space of the frame interface limited by the two walls, is compensated for by the tolerance compensation element. For this purpose, the tolerance compensation element and screw can first be loosely inserted into the wall opening and screwed to the drive unit. The tolerance compensation element thus aligns itself with the position of the drive unit. By tightening the screw to a defined torque, the tolerance compensation element is radially deformed, at least until a portion of it touches the inside of the wall opening. This contact establishes the force-fit with the wall opening to secure the drive unit to the first wall.

[0010] The first and second walls of the frame interface are preferably arranged at a predefined fixed distance from each other. Particularly preferably, the frame interface is at least partially U-shaped, especially wherein the first and second walls are arranged parallel to each other at the predefined fixed distance and are preferably connected to each other by means of a connecting area. Preferably, the frame interface, i.e., the first wall, the second wall, and the connecting area, is formed as a single-piece component.

[0011] The drive arrangement allows for an assembly of the drive unit and frame interface that is advantageous with regard to mechanical loads. The tolerance compensation element ensures backlash-free mounting of the drive unit between the two walls, preventing bending and / or tensile stress in either component, for example, when the drive unit is screwed to the walls from both sides. This allows, for instance, the use of particularly lightweight materials for the drive assembly components.

[0012] The dependent claims contain preferred further developments of the invention.

[0013] Preferably, an inner wall of the tolerance compensation element, when in its undeformed state, has a concave wall region. The concave wall region is defined as at least a section of the inner wall that, viewed in longitudinal section of the tolerance compensation element, is curved radially outwards. Preferably, the concave wall region can also include straight, for example, axially aligned, sections located between two radially outwardly curved sections. If, for example, an outer wall of the tolerance compensation element is straight or cylindrical, the cross-section of the wall of the tolerance compensation element thus tapers from the axial ends towards the center. Particularly preferably, the concave wall region extends over the entire axial length of the tolerance compensation element.In particular, the concave wall section results in a thinner wall thickness for the tolerance compensation element compared to surrounding areas, essentially in an axially central region. This allows for a more targeted radial deformation originating from the concave wall section. The curvature of the concave wall section thus enables the radial deformability of the tolerance compensation element in a particularly targeted and simple manner.

[0014] Preferably, the outer wall of the tolerance compensation element, when in its undeformed state, has a cylindrical wall section. This allows for a particularly simple and cost-effective design. Furthermore, this design enables the tolerance compensation element to be inserted into the wall opening particularly easily and precisely.

[0015] Preferably, the outer wall of the tolerance compensation element, when in its undeformed state, has a convex wall region. The convex wall region is defined as at least a section of the outer wall that, viewed in longitudinal section of the tolerance compensation element, is curved radially outwards. Preferably, the convex wall region can also include straight, for example, axially aligned sections located between two radially outwardly curved sections. The convex wall region can, for example, be considered a bulbous wall region. A combination of a convex wall region on the outer wall and a concave wall region on the inner wall is particularly advantageous. This geometry can also be considered a geometry with a pre-formed radial expansion, which allows the radial expansion to be achieved by means of the screw connection to be produced in a particularly targeted and simple manner.

[0016] Preferably, the tolerance compensation element is designed to widen in the longitudinal direction, essentially in the center. This means that axial compression preferably leads to an increasingly bulbous geometry of the tolerance compensation element. This allows a centrally located area to first contact the inside of the wall opening. As a result, even with varying gap sizes between the first wall and the drive unit, a reliable force-fit connection can be established through the widening of the tolerance compensation element.

[0017] Preferably, the tolerance compensation element has a flange on one side facing away from the drive unit. The flange is defined as a region of the tolerance compensation element that has a larger outer diameter than the other regions. Preferably, the flange is designed so that it does not deform when tightened with the screw.

[0018] The tolerance compensation element is particularly preferably designed such that the flange limits its maximum axial compression by bearing against the first wall when bolted, preferably such that the maximum axial compression results in a minimal radial expansion, during which the tolerance compensation element bears at least partially against the inside of the wall opening. In particular, the tolerance compensation element thus has a shaft length extending to the underside of the flange, which is designed such that the flange limits a predefined maximum deformation length. In particular, the shaft length is greater than the sum of the wall thickness of the first wall and the width of the gap. Preferably, the deformation length is at least 10%, more preferably at least 30%, of the axial length of the entire tolerance compensation element.The flange thus allows for particularly easy assembly of the drive assembly in order to achieve the desired screwed-in condition, since, for example, the screw is simply screwed in until the flange rests against the first wall.

[0019] Preferably, the first wall has a shoulder, in particular wherein the flange can be pressed against an axial end face of the shoulder when the screw is tightened with the predefined tightening torque. The flange and the shoulder are designed to center the tolerance compensation element relative to the wall opening. Preferably, a fit, in particular a clearance fit or a transition fit, is formed between the flange and the shoulder. This allows for a particularly simple and precise arrangement of the tolerance compensation element in the wall.

[0020] Preferably, the drive unit comprises a drive element and a mounting plate, wherein the drive element and the mounting plate are connected to each other, for example by means of a screw connection. The screw of the first mounting plate is screwed into the mounting plate. Preferably, the mounting plate has a threaded nut into which the screw is screwed.

[0021] Preferably, the tolerance compensation element is made of metal, in particular steel or aluminum. This allows for a particularly simple and cost-effective design, enabling reliable and robust mounting of the drive unit to the first wall.

[0022] Preferably, the drive unit rests against the second wall, with the second bracket having a screw connection. In particular, the drive unit is firmly connected to the second wall by means of the screw connection of the second bracket. Preferably, the screw connection has at least one screw, preferably several screws. By directly screwing the drive unit to the second wall, a particularly simple and robust assembly of the drive assembly is possible. Preferably, when assembling the drive assembly, the drive unit is first screwed to the second wall by means of the screw connection, and then the gap to the first wall is bridged by means of the tolerance compensation element.

[0023] Preferably, the drive unit comprises a motor and / or a gearbox. The specific arrangement and mounting, at least partially within the frame interface, ensures an optimal, reliable connection with advantageous mechanical force distribution, thus enabling a long service life for the drive unit. Furthermore, a low weight for the drive assembly can be achieved in a simple and cost-effective manner.

[0024] Furthermore, the invention leads to a vehicle, preferably a vehicle propelled by muscle power and / or motor power, preferably an electric bicycle, which includes the described drive arrangement. The frame interface is preferably part of the vehicle frame.

[0025] Preferably, the tolerance compensation element is arranged on the side of the drive unit of the drive assembly facing away from a sprocket of the vehicle. This means that the second mounting point of the drive assembly is located on the sprocket side of the drive unit. Since the greatest forces act on the drive unit and the frame interface in the area of ​​the sprocket, this avoids high mechanical stress on the tolerance compensation element. Instead, particularly when the drive unit and the second mounting point are directly bolted together, a particularly direct and robust mechanical connection of the drive unit to the frame interface can be provided.

[0026] Furthermore, the invention leads to a method for assembling a drive assembly, preferably the drive assembly described above. The method comprises the following steps: Positioning a drive unit at least partially between a first wall and a second wall of a frame interface, securing the drive unit to the second wall by means of a second bracket, arranging a sleeve-shaped tolerance compensation element in a wall opening of the first wall, and screwing the tolerance compensation element to the drive unit by means of a screw.

[0027] The screw is tightened to a predefined torque such that the tolerance compensation element expands radially, at least until it partially rests against the inner side of the wall opening in the first wall. This creates a first support structure formed by the tolerance compensation element and the screw, which is used to attach the drive unit to the first wall. This method allows for particularly simple installation of the drive assembly in the frame interface, enabling reliable fastening and the use of defined load conditions, preferably a neutral load condition or a low tensile load on the drive unit.

[0028] Preferably, the tolerance compensation element has a flange on a side facing away from the drive unit. The screw is tightened at least until the flange of the tolerance compensation element rests against the first wall. Additionally, the screw is tightened to a maximum extent until the ratio of tightening torque change to tightening angle change reaches a value of at least 0.5, preferably 1. This ratio can be considered the slope of a torque curve with respect to the angle of rotation during tightening. In other words, the screw is tightened to a maximum extent until the slope of the torque curve increases significantly. This ensures, on the one hand, sufficient radial expansion of the tolerance compensation element with the first wall and, on the other hand, prevents tensile stress on the drive unit from being caused by overtightening the screw after the flange is in place.

[0029] Preferably, the predefined tightening torque is a maximum of 30 Nm, and in particular a maximum of 20 Nm. Brief description of the drawings

[0030] The invention is described below with reference to an exemplary embodiment in conjunction with the figures. In the figures, functionally identical components are each identified by the same reference numerals. The figures show: Figure 1 shows a sectional view of a drive arrangement according to a preferred embodiment of the invention; Figure 2 shows a detailed sectional view of the drive arrangement. Figure 1 Figure 3 shows a detailed sectional view of the drive arrangement of the Figure 1 in the unbolted state, and Figure 4 a simplified schematic view of a torque curve when the drive assembly is bolted together. Figure 1 . Preferred embodiments of the invention

[0031] Figure 1shows a sectional view of a drive arrangement 1 according to a preferred embodiment of the invention. Figure 2 shows a detailed sectional view of the drive arrangement 1 of the Figure 1 . In the Figure 1 and 2 The drive assembly is shown in its fully assembled state. Preferably, the drive assembly is part of an electric bicycle (not shown).

[0032] The drive arrangement 1 comprises a (schematically represented) drive unit 2, which includes a drive element 20 comprising a motor and a gearbox, and two retaining plates 23, 25. The drive unit 2 is accommodated within a U-shaped frame interface 3. The frame interface 3 has a first wall 31 and a second wall 32, between which the drive unit 2 is arranged.

[0033] The two retaining plates 23, 25 are screwed directly to the drive element 20 and serve for fastening to the frame interface 3. For this purpose, the drive arrangement 1 has a first bracket 51, by means of which the drive unit 2 is attached to the first wall 31, and a second bracket 52, by means of which the drive unit 2 is attached to the second wall 32.

[0034] The second bracket 52 has a screw connection with a screw 52, ​​by means of which the first retaining plate 23 is directly screwed to the second wall 32. The screw 52 is screwed into a threaded nut 26 of the first retaining plate 23. The first retaining plate 23, and thus also the drive unit 2, rests directly against an inner surface 32a of the second wall 32.

[0035] In the first wall 31, a wall opening 31b is designed as a passageway. The wall opening 31b is designed in two stages and has a step 31c.

[0036] Through the wall opening 31b, a screw 5 of the first bracket 51 can be screwed into the drive unit 2 to enable the fastening of the drive unit 2 to the first wall 31, as described below.

[0037] The first bracket 51 has a tolerance compensation element 4. The tolerance compensation element 4 is sleeve-shaped and projects through the wall opening 31b, resting against the second retaining plate 25 of the drive unit 2. The tolerance compensation element 4 thus bridges a gap 6 between the first wall 31 and the second retaining plate 25 of the drive unit 2.

[0038] The screw 5 of the first bracket 51 is screwed into a threaded nut 27 of the second retaining plate 25 of the drive unit 2, protruding through the tolerance compensation element 4.

[0039] The screw connection is such that a rigid connection exists between the drive unit 2 and the first wall 31 via the first bracket 51, i.e., tolerance compensation element 4 and screw 5, both axially and radially with respect to a screw axis 59. The screw connection is designed to prevent tensile stress on the drive unit 2 between the two walls 31, 32 of the frame interface 3. Instead, the drive unit 2 is in a neutral or slightly tensile state when fully screwed in. This is achieved by the specific design of the deformable tolerance compensation element 4.

[0040] To describe the tolerance compensation element, reference is first made to the following: Figure 3 , which shows a detailed sectional view of the drive arrangement of the Figure 1 and 2 shown in an unbolted and undeformed state.

[0041] As in the Figure 3 As can be seen, the tolerance compensation element 4 has an outer wall 42 with a cylindrical wall section 42a. The outer diameter 47 of the cylindrical wall section 42a is smaller, preferably 5% to 10% smaller, than the inner diameter 37 of the wall opening 31b, so that the tolerance compensation element 4 can be easily arranged in the wall opening 31b.

[0042] On one side facing away from the drive unit 2, the tolerance compensation element 4 has a flange 44 which has a larger outer diameter 48 than the cylindrical wall area 42a and than the inner diameter 37 of the wall opening 31b.

[0043] An inner wall 41 of the tolerance compensation element 4 has a concave wall region 41a that extends over the entire axial length of the tolerance compensation element 4. The concave wall region 41a causes the wall thickness of the tolerance compensation element 4 to decrease axially towards the center, starting from both end faces. This allows the tolerance compensation element 4 to deform more easily and precisely when the screw 5 is tightened further after the screw head 51 has come into contact with the tolerance compensation element 4.

[0044] In detail, after the screw head 51 is seated on the flange 44, the tolerance compensation element 4 is axially compressed by the screw connection as the screw is tightened further. Due to the concave wall region 41a of the inner wall 41, this axial compression leads to a plastic deformation of the tolerance compensation element 4 in the form of a radial expansion of at least one deformation region 45, as indicated by the arrows in Figure 2 indicated. This deformation area 45 lies essentially in the center of the tolerance compensation element 4 in the axial direction.

[0045] The radial expansion results in a portion of an outer surface 40 of the tolerance compensation element 4 being applied to an inner surface 31a of the wall opening 31b of the first wall 31. The tolerance compensation element 4 is thereby axially compressed by tightening the screw 5 until the flange 44 abuts the shoulder 31c of the wall opening 31b.

[0046] A compression length 46 corresponds to the difference between the shaft length 42b of the cylindrical wall section 42a and the sum of the width of the gap 6 and the wall thickness 31d up to the shoulder 31c. In particular, the shaft length 42b and / or the wall thickness 31d are specifically designed such that a sufficiently large compression length 46 results in minimal radial expansion until the surface 40 makes full contact with the inner surface 31a of the wall opening 31b and, in particular, is pressed against it. This creates, on the one hand, a force-fit in the axial direction and, on the other hand, a backlash-free arrangement in the radial direction, so that the drive unit 2 is reliably attached to the first wall 31 by means of the first bracket 51.

[0047] To achieve a particularly precise relative alignment of the drive unit 2 to the first wall 31, the screw connection, i.e., screw 5 and tolerance compensation element 4, is precisely centered relative to the wall opening 31b. For this purpose, the flange 44 of the tolerance compensation element 4 and the shoulder 31c of the wall opening 31b are specifically designed to achieve this centering. In detail, a transition fit is formed between the flange 44 and the shoulder 31c.

[0048] To ensure reliable holding of the screw connection, screw 5 is tightened with a predefined tightening torque of 50. This tightening torque is specifically designed and is described below in relation to the Figure 4 described. Figure 4 This shows a simplified schematic view of a torque curve during a screw connection of the drive assembly. Figure 1 .

[0049] This is shown in Figure 4a diagram with an exemplary torque curve 150, which, when tightening, starts from a state when the screw head 51 rests against the tolerance compensation element 4, where the tolerance compensation element 4 is still undeformed, as in Figure 3 The X-axis 102 indicates the angle of rotation in degrees, while the Y-axis 101 indicates the torque in Newton meters.

[0050] In region 150, the torque 150 increases due to the resistance of the tolerance compensation element 4, in this case, for example, within the region of elastic deformation of the tolerance compensation element 4. Following this increase in torque 150, a region 156 ensues in which the plastic deformation of the tolerance compensation element 4 occurs, i.e., axial compression and radial expansion. In this region 156, the torque 150 increases only slightly over a large range of the rotation angle 102.

[0051] As soon as the flange 44 abuts the shoulder 31c of the first wall 31, the slope of the torque curve 150 increases significantly, as shown in Figure 4 in area 157. If further tightening with a high torque were to occur, the drive unit 2 would subsequently be subjected to tensile stress. To avoid a high tensile load and instead preferably ensure a neutral or only slightly stressed arrangement of the drive unit 2, the screw 5 is tightened to a maximum of the predefined tightening torque 50. The tightening torque 50 is reached when the torque curve 150 reaches a slope 154 of 1. This is the case when, as schematically indicated, the ratio of tightening torque change 151 to tightening angle change 152 is equal to 1. Preferably, the tightening torque 50 is approximately 20 Nm, for example when using an M8 screw.

Claims

1. Drive arrangement of a vehicle which can be operated, in particular, by muscle power and / or motor power, comprising: - a drive unit (2), - a frame interface (3), wherein the drive unit (2) is arranged at least partially between a first wall (31) and a second wall (32) of the frame interface (3), - a first bracket (51) which holds the drive unit (2) on the first wall (31), and - a holder (52) which holds the drive unit (2) on of the second wall (32), wherein the first bracket (51) comprises a screw (5) and a sleeve-shaped tolerance compensation element (4), wherein the tolerance compensation element (4) is arranged at least partially within a wall opening (31b) of the first wall (31) and so as to bear against the drive unit (2), and is screwed to the drive unit (2) by means of the screw (5), and wherein the tolerance compensation element (4) is designed so as to widen radially as a result of the screw connection in order to at least partially bear against an inner side (31a) of the wall opening (31b) when the screw (5) is tightened with a predefined tightening torque (50).

2. Drive arrangement according to Claim 1, wherein an inner wall (41) of the tolerance compensation element (4) has a concave wall region (41a) in the undeformed state.

3. Drive arrangement according to either of the preceding claims, wherein an outer wall (42) of the tolerance compensation element (4) has a cylindrical wall region (42a) in an undeformed state.

4. Drive arrangement according to either of Claims 1 or 2, wherein an outer wall (42) of the tolerance compensation element (4) has a convex wall region (42a) in an undeformed state.

5. Drive arrangement according to one of the preceding claims, wherein the tolerance compensation element (4) is designed so as to widen substantially centrally in the longitudinal direction.

6. Drive arrangement according to one of the preceding claims, wherein the tolerance compensation element (4) has a flange (44) on one side facing away from the drive unit (2).

7. Drive arrangement according to Claim 6, wherein the tolerance compensation element (4) is designed in such a way that, by bearing against the first wall (31) in the screwed state, the flange (44) limits a maximum axial compression of the tolerance compensation element (4).

8. Drive arrangement according to either of Claims 6 or 7, wherein the first wall (31) has a shoulder (31c), and wherein the flange (44) and the shoulder (31c) are designed to centre the tolerance compensation element (4) relative to the wall opening (31b).

9. Drive arrangement according to one of the preceding claims, wherein the drive unit (2) has a drive element (20) and a holding plate (25), in particular with a threaded nut (27), wherein the drive element (20) and the holding plate (25) are connected to each other, and wherein the screw (5) of the first bracket (51) is screwed into the holding plate (25).

10. Drive arrangement according to one of the preceding claims, wherein the tolerance compensation element (4) is made of metal, in particular steel or aluminium.

11. Drive arrangement according to one of the preceding claims, wherein the drive unit (2) bears against the second wall (32), and wherein the second bracket (52) has a screw connection.

12. Vehicle, in particular vehicle which can be operated by muscle power and / or motor power, preferably electric bicycle, comprising a drive arrangement (1) according to one of the preceding claims.

13. Method for assembling a drive arrangement (1), in particular according to one of the preceding claims, comprising the steps: - positioning a drive unit (2) at least partially between a first wall (31) and a second wall (32) of a frame interface (3), - fastening the drive unit (2) to the second wall (32) by means of a second bracket (52), - arranging a sleeve-shaped tolerance compensation element (4) in a wall opening (31b) of the first wall (31), and - screwing the tolerance compensation element (4) to the drive unit (2) by means of a screw (5), wherein the screw (5) is tightened with a predefined tightening torque (50) in such a way that the tolerance compensation element (4) widens radially at least until it bears at least partially against an inner side (31a) of the wall opening (31b), with the result that the tolerance compensation element (4) and the screw (5) form a first bracket (51) for fastening the drive unit (2) to the first wall (31).

14. Method according to Claim 13, wherein the tolerance compensation element (4) has a flange (44) on one side facing away from the drive unit (2), and wherein the screw (5) is tightened at least until the flange (44) bears against the first wall (31), and wherein the screw (5) is tightened at most until a ratio of change in tightening torque (151) to change in tightening angle of rotation (152) reaches a value of at least 0.5, in particular 1.

15. Method according to Claim 13 or 14, wherein the predefined tightening torque is at most 30 Nm, in particular at most 20 Nm.