Drive System for a Vehicle Driveable Directly by Muscle Force, Method for Changing a Roller of Such a Drive System and Production Method

Abstract

The invention relates to a drive system for a vehicle drivable by muscle force, in particular for a skateboard, said drive system comprising at least one axle and at least one wheel (1) which has an electric motor (10), wherein the electric motor (10) comprises a stator (11), which can be connected to the axle, and a rotor (12) which is rotatable about the stator. The invention is characterised in that the wheel (1) has a roller (20) which forms a running surface (24), wherein the roller (20) is or can be replaceably connected to the rotor (12). The invention further relates to a method for changing a roller (20) of such a drive system and to a production method.

Claims

1. A drive system for a vehicle drivable by muscle force, in particular for a skateboard, with at least one axle and at least one wheel (1), which has an electric motor (10), characterized in that the electric motor (10) comprises a stator (11), which can be connected to the axle, and a rotor (12) that is rotatable around the stator (11), and the wheel (1) has a roller (20) that forms a running surface (24), wherein the roller (20) is or can be replaceably connected to the rotor (12).

2. The drive system according to claim 1, characterized in that the roller (20) is or can be positively connected with the rotor (12).

3. The drive system according to claim 1 or 2, characterized in that the roller (20) has at least one engaging element (23), which positively engages into a receiving element (27) of the rotor (12).

4. The drive system according to claim 3, characterized in that the engaging element (23) consists of a polygonal inner circumferential surface of the roller (20), and the receiving element (27) consists of a polygonal outer circumferential surface (12a) of the rotor (12).

5. The drive system according to one of the preceding claims, characterized in that the rotor (12) has a bushing (15) with a front plate (14).

6. The drive system according to claim 3, characterized in that the receiving element (27) consists of a recess (13) in the front plate (14) of the bushing (15).

7. The drive system according to one of the preceding claims, characterized in that the rotor (12) is or can be connected with a retaining plate (30) that fixes the roller (20) along a longitudinal axis.

8. The drive system according to claim 7, characterized in that the engaging element (23) is positively fixed between rear surface (13a) of the recess (13) and the retaining plate (30) in an assembled state of the roller (20).

9. The drive system according to claim 7 or 8, characterized in that the retaining plate (30) has ventilation openings (31).

10. The drive system according to one of the preceding claims, characterized in that the roller (20) has a roller core (21) made out of a first material and a jacket layer (22) made out of a second material, wherein the jacket layer (22) is cast onto the roller core (21).

11. The drive system according to claim 10, characterized in that the engaging element (23) is integrally designed with the roller core (21).

12. The drive system according to one of the preceding claims, characterized in that the electric motor (10) is coupled with a controller that has a telemetry module.

13. The drive system according to claim 12, characterized in that the electric motor (10) has a temperature sensor and/or rotational speed sensor that is or can be signal-connected with the controller.

14. The drive system according to one of the preceding claims, characterized in that the electric motor (10) has wiring that is connected with a circuit board, wherein the circuit board is longitudinally axially arranged inside of the stator (11).

15. The drive system according to one of claims 7 to 14, characterized in that the retaining plate (30) is non-rotatably coupled with the front plate.

16. The drive system according to claim 15, characterized in that the retaining plate (30) has fastening holes (32) that align flush with threaded holes (14b) in the front plate (14) in the assembled state.

17. The drive system according to one of claims 7 to 16, characterized in that at least parts of the retaining plate (30) abut flush against the front plate (14).

18. The drive system according to one of claims 5 to 17, characterized in that the bushing (15) has a cylindrical circumferential wall (15a), with which the front plate (14) is integrally designed, in particular as an integral deep-drawn part.

19. A vehicle drivable by muscle force, in particular a skateboard, with at least one drive system according to one of the preceding claims.

20. A method for changing a roller (20) of a drive system or vehicle according to one of the preceding claims, wherein the method consists of the following steps: Releasing the connection between the roller (20) and rotor (12), in particular releasing the retaining plate (30); Removing the roller (20) from the rotor (12); Positively connecting a new roller (20) with the rotor (12); and Fixing the new roller (20) to the rotor (12), in particular with the retaining plate (30).

21. The method for changing a roller (20) of a drive system and/or vehicle according to one of the claims 1 to 19, wherein the method consists of the following steps: Providing a roller core (21) made out of a first material; Placing the roller core (21) into a mold; Casting a second material into the mold to form a jacket layer (22), wherein at least areas of the roller core (21) are recast; and Removing the roller (20) from the mold.

Description

[0042] The invention will be explained in more detail below based on an exemplary embodiment, with reference to the attached, schematic drawings. Shown therein:

[0043] FIG. 1 is a perspective, exploded view of the wheel of a drive system according to the invention in a preferred exemplary embodiment, wherein part of the jacket layer of the roller has been removed for illustrative purposes;

[0044] FIG. 2 is a side view of the wheel according to FIG. 1;

[0045] FIG. 3 is a front view of the wheel according to FIG. 1;

[0046] FIG. 4 is a rear view of the wheel according to FIG. 1;

[0047] FIG. 5 is a cross sectional view through the wheel according to FIG. 3 along the A-A line;

[0048] FIG. 6 is a perspective, partial sectional view of a rotor of a drive system according to the invention in another preferred exemplary embodiment; and

[0049] FIG. 7 is a perspective, partial sectional view of an electric motor of a drive system according to the invention with the rotor from FIG. 6.

[0050] FIGS. 1 to 5 show a wheel, which preferably is part of a drive system for a skateboard. The wheel can also be used as a drive system for longboards, streetboards, snakeboards, scooters, wakeboards or roller skates.

[0051] The wheel 1 comprises an electric motor 10 made up of a stator 11 and rotor 12. The stator 11 can preferably be fixedly connected with an axle of the drive system. In particular, the stator 11 can be screwed to an axle. The stator 11 is preferably fixed on the axle of the drive system using a thread-locking fluid, which prevents the screw connection between the stator 11 and axle of the drive system from inadvertently loosening.

[0052] The rotor 12 is pivoted in relation to the stator 11. In particular, an outer bearing 17a and an inner bearing 17b are provided, which rotatably connect the stator 11 with the rotor 12. The outer bearing 17a and inner bearing 17b preferably each comprise a deep groove ball bearing. The deep groove ball bearings can be sealed.

[0053] The rotor 12 has a bushing 15, which incorporates several permanent magnets 16. The permanent magnets 16 are preferably uniformly distributed over the inner circumference of the bushing 15 and fixedly connected with the bushing 15.

[0054] The rotor 12 further comprises a front plate 14, which seals the bushing 15 on the face. The front plate 14 can be inserted into the bushing 15 via an interference fit. The rear side of the bushing 15 is preferably sealed by a stator ring 18a, the inner bearing 17b and a bushing ring 18b. As a whole, this yields a well encapsulated electric motor 10, which is comparatively resistant to contamination or liquid entry.

[0055] In this conjunction, let it be noted that the wiring of the electric motor 10, i.e., the live windings for generating the dynamic magnetic field, have not been illustrated for reasons of clarity. The windings are preferably non-rotatably arranged on the stator 11. The windings are here designed in such a way that the electric motor 10 has a comparatively large torque. As a whole, the electric motor 10 has an optimized configuration in terms of torque so as to apply a sufficient driving force. This makes sense in particular because the electric motor 10 is preferably conceived as a gearless direct drive. The wiring of the electric motor 10 can be combined into a circuit board, which is fixedly arranged inside of the stator 11. This makes it easier to contact the electric motor 10 with an energy storage system, for example an accumulator or battery. For example, such an accumulator can be arranged on a base plate, wherein the base plate additionally carries the axle on which the electric motor 10 or wheel 1 is non-rotatably fixed.

[0056] Apart from the electric motor 10, the wheel 1 also encompasses a roller 20. The roller 20 is comprised of a roller core 21 and a jacket layer 22. The roller core 21 and jacket layer 22 can here have varying materials. The jacket layer 22 forms a running surface 24 on its outer circumferential surface. The jacket layer 22 is preferably fixedly cast with the roller core 21. As a consequence, there is an integral bond between the roller core 21 and jacket layer 22, which is characterized by an especially high stability.

[0057] As readily discernible on FIG. 1, the roller core 21 has engaging elements 23. The engaging elements 23 are plate-like in design, and extend radially to a longitudinal axis or rotational axis of the wheel 1. In particular, each engaging element 23 yields an extension in the longitudinal direction of the roller core 21 or projects over the roller core 21 in the longitudinal direction. Gaps 25 spaced apart from each other are arranged between the engaging elements 23 in the circumferential direction of the roller core 21. The engaging element 23 has an essentially rectangular outer contour.

[0058] As readily discernible on FIG. 2, the engaging elements 23 on the roller core 21 project over a cylindrical section of the roller core 21. Gaps 25 are formed between the individual engaging elements 23, into which the material of the jacket layer 22 can flow while casting the roller core 21. As a result, a positive connection is realized in addition to the integral bond between the jacket layer 22 and roller core 21. It is also possible that the outer circumferential surface of the roller core 21 be structured, for example have a grooved structure or nap structure, so that a good, in particular positive, connection is established with the jacket layer 22 while casting the roller core 21.

[0059] As a whole, several engaging elements 23 are distributed over the circumference of the roller core 21. The engaging elements 23 essentially form a gearing, wherein the individual teeth or engaging elements 23 are spaced apart uniformly from each other.

[0060] Recesses 13 are arranged on the front plate 14 complementarily to the engaging elements 23 on the roller 20 or on the roller core 21. As a whole, the front plate 14 has several recesses 12 on the face, which each exhibit an outer contour. Another number of recesses 13 is possible. The recess 13 and engaging element 23 are preferably dimensioned in such a way that the engaging element 23 engages into the recess 13 with a clearance fit.

[0061] In particular the recess 13 has a rear surface 13a, a floor surface 13b and two lateral surfaces 13c. The width of the lateral surfaces 13c essentially corresponds to the wall thickness of the engaging elements 23.

[0062] The recess 13 extends radially from an outer circumference of the front plate 14 toward the inside. The front plate 14 can have an outer diameter that essentially corresponds to the inner diameter of the roller core 21. It is here provided that the roller core 21 can be guided over the front plate 14 with a clearance fit.

[0063] A retaining plate 30 is provided to fix the positive connection between the roller 20 and rotor 12. The retaining plate 30 has an outer diameter that essentially corresponds to the outer diameter of the roller core 21. It is also possible for the retaining plate 30 to have an outer diameter larger than the outer diameter of the roller core 21, but smaller than the outer diameter of the jacket layer 22 or roller 20. The retaining plate 30 has fastening holes 32 that align flush with the threaded holes 14b in the front plate 14 in the assembled state. The fastening holes 32 and threaded holes 14b can be used to screw the retaining plate 30 with the front plate 14. In this way, the retaining plate 30 is non-rotatably coupled with the front plate 14 or rotor 12.

[0064] In the assembled state, at least parts of the retaining plate 30 abut flush against the front plate 14. In particular, it is provided that a distance be set between the retaining plate 30 and rear surface 13a of the recess 13 in the front plate 14 that essentially corresponds to the wall thickness of the engaging element 23. In this way, the engaging element 23 can be non-positively clamped between the front plate 14 and retaining plate 30 in addition to the positive connection. This improves the connection between the roller 20 and electric motor 10.

[0065] As readily discernible on FIG. 5, the retaining plate 30 abuts flush against the front plate 14 only with its outer edge and the fastening holes 32. In other words, the retaining plate 30 has a reshaped outer edge, so that a ventilation space 33 forms between the retaining plate 30 and front plate 14. Several ventilation openings 31 located in the retaining plate 30 empty into the ventilation space 33. The ventilation openings 31 are arranged on a circle, and spaced uniformly apart from each other. Nine ventilation openings 31 are provided in the exemplary embodiment shown.

[0066] An air flow that helps cool the electric motor 10 is generated through the ventilation holes 31 behind the retaining plate 30. The air here passes through the ventilation holes 31 and into the ventilation space 33 formed between the retaining plate 30 and front plate 14. The air can again exit the ventilation space 33 through the same ventilation openings 31.

[0067] Three fastening holes 32 are provided inside of the circle described by the ventilation openings 31. The front plate correspondingly has three threaded holes 14b. The threaded holes 14b and fastening holes 32 are each arranged at the same distance relative to the rotational axis of the wheel 1.

[0068] Visible on FIG. 4 is a rear view of the wheel 1. As evident, the stator 11 has an axial hole 11b. The axial hole 11b can encompass a thread. The axial hole 11b can be used to fix the stator 11 or entire wheel 1 on an axle. As further readily discernible, the stator ring 18a fixedly joined with the stator 11 has several openings. Each opening forms a cable outlet 19, so that the cables required for electrically contacting the stator 11 can be run out of the electric motor 10. Since the stator ring 18a is rigidly joined with the stator 11, and thus non-rotatably fixed on the axle, the provided arrangement of cable outlets 19 is here beneficial. A plug connector can also be arranged in the cable outlets 19. In general, the connection between the electric motor 10 and a controller can be established by two or more plug-connectable wiring harnesses. At least one plug connection can be arranged in the cable outlets 19, thereby enabling an easy electrical connection or disconnection directly at the electric motor 10.

[0069] The inner bearing 17b extends around the stator ring 18a, and can be designed as a deep groove ball bearing. Also provided to seal the electric motor 10 is the bushing ring 19b, which is fixedly connected with the bushing 15 of the rotor 12. In particular, the bushing ring 18b can be joined with the bushing 15 by way of an interference fit.

[0070] FIG. 5 shows a detailed illustration of the inner structural design of the wheel 1. Readily discernible in particular is the axial hole 11b of the stator 11. The axial hole 11b serves establish a connection with the axle of the drive system. In addition, the stator 11 comprises a pin 11a, which projects over the stator 11 along the longitudinal axis. The pin 11a carries the outer bearing 17a, which can be designed as a deep groove ball bearing.

[0071] The outer bearing 17a is fitted into an annular extension 14a of the front plate 14.

[0072] As further readily discernible on FIG. 5, both the front plate 14 and bushing ring 18b each have a radial flange 26, which projects over the bushing 15. This prevents dirt or dust from penetrating into the electric motor 10.

[0073] Finally, FIG. 5 clearly shows that the roller 10 consists of two parts. Visible in particular is the roller core 21, which has engaging elements 23 to positively connect the roller 20 with the rotor 12 of the electric motor 10. The roller 20 further comprises a jacket layer 22, which is in particular integrally joined with the roller core 21. The jacket layer 22 can consist of polyurethane, which is characterized by good adhesive characteristics. The jacket layer 22 makes up the running surface 24 of the roller 20. FIGS. 6 and 7 depict an alternative exemplary embodiment of the drive system, wherein in particular the structural design of the electric motor 10 is shown. FIG. 6 presents the rotor 12 of the electric motor 10 in a perspective, partial sectional view. The rotor consists of a bushing 15, which has an essentially cylindrical circumferential wall 15a and a front plate 14 integrally designed with the circumferential wall 15a. The front plate 14 seals the bushing 15 to the outside. In other words, the front plate is aligned on an axle relative to the longitudinally axial exterior side of the axle in the assembled state of the rotor 12. The front plate 14 incorporates an annular extension 14a that can accommodate a ball bearing.

[0074] The bushing 15 with the front plate 14 is preferably designed as an integral deep-drawn part. This makes the rotor 12 especially easy to manufacture. Provided on the side lying opposite the front plate 14 is a bushing ring 18b, which seals the bushing 15 on an axle toward the interior side in the assembled state of the rotor 12. In the area of the bushing ring 18b, the rotor 12, in particular the bushing 15, has a radial flange 26 that serves as a stop for a roller 20.

[0075] The circumferential wall 15a of the rotor 12 is essentially cylindrical in design, and at least sections thereof comprise a polygonal outer profile. In other words, the rotor 12 or bushing 15 has a polygonal outer circumferential surface 12a. The outer circumferential surface 12a forms a receiving element 27 for positively engaging a complementarily designed engaging element 23 of the roller 20. It is specifically provided that the replaceable roller 20 have an inner circumferential surface also having a polygonal design. In particular, several flattened circumferential wall sections can here be provided, which positively intermesh in the assembled state of the roller 20 on the rotor 12, wherein the positive connection comes about in particular in the circumferential direction. As readily discernible on FIG. 6, the interior side of the circumferential wall 15a is also provided with flat or flattened surfaces. These flattened surfaces yield magnetic receptacles 12b, so that flat or non-curved permanent magnets 16 can be easily glued onto the inner circumferential surface of the rotor 12. In this regard, the flattened areas of the circumferential wall 15a have a dual function. The flattened areas permit a positive connection with a replaceable roller 20 toward the outer circumferential surface 12a. The flattened areas form magnet receptacles 12 toward the inner circumferential surface for the easy and reliable accommodation of permanent magnets 16.

[0076] The roller 20 positively fixed with the rotor 12 in the circumferential direction via the polygonal outer contour of the bushing 15 can be connected in a longitudinally axial direction with the front plate 14 of the rotor 12, for example by a screw connection. In particular, the front plate 14 can be provided with holes (not shown here), in particular threaded holes, so as to fix the replaceable roller with a retaining plate 30 to the rotor 12. It can here be provided that the retaining plate 30 be integrally designed with the roller 20, in particular the roller core 21. In other words, at least the roller core 21 can also be designed as a deep-drawn part with an integrally designed retaining plate 30. The retaining plate 30 integrally designed with the roller core 21 preferably also has holes that align flush with the holes or threaded holes in the front plate 14 of the rotor 12, thereby enabling a screw connection between the roller core 21 and rotor 12.

[0077] FIG. 7 presents a perspective, partial sectional view of the electric motor 10, which has a rotor 12 according to FIG. 6. As evident, the permanent magnets 16 are arranged, in particular glued, into the magnet receptacles 12b. The stator 11 has wiring harnesses 19 at one inner axial end of the rotor 12. At the inner axial end, the rotor 12 is mounted so that it can be rotated relative to the bushing ring 18b by way of an inner bearing 17b designed as a ball bearing. At an outer axial end of the rotor 12, the stator 11 is mounted via an outer bearing 17 that is placed, in particular pressed, into the annular extension 14a of the rotor 12. The stator further has winding cores 29, which extend radially outward from the longitudinal axis of the stator 11, and carry windings 28.

[0078] In general, it is provided for the drive system that the electric motor 10, in particular the bushing 15, have an outer diameter that measures at most 80 mm, in particular at most 70 mm, in particular at most 65 mm, in particular 63 mm. This ensures that the wheel 1 with the roller 20 will have an overall diameter that essentially corresponds to commercially available skateboard rollers. As a result, existing skateboards or similar pieces of sports equipment can be easily retrofitted.

[0079] The length of the wheel 1 preferably measures at most 75 mm, in particular at most 72 mm, in particular at most 70 mm. This format also makes it easier to retrofit existing skateboards.

[0080] The entire drive system can additionally encompass a telemetry module, so that the electric motor 10 can be remote controlled. For example, a user can control the electric motor via his or her smartphone and a WLAN, Bluetooth or Zigbee connection. The electric motor 10 can further be adjusted to allow recuperative braking. The electric motor 10 can thus also act as a generator, wherein braking energy is converted into electrical energy, and returned to an energy storage system, for example an accumulator. This expands the range of the drive system.

REFERENCE LIST

[0081] 1 Wheel [0082] 10 Electric motor [0083] 11 Stator [0084] 11a Pin [0085] 11b Axial hole [0086] 12 Rotor [0087] 12a Outer circumferential surface [0088] 12b Magnet receptacle [0089] 13 Recess [0090] 13a Rear surface [0091] 13b Floor surface [0092] 13c Lateral surface [0093] 14 Front plate [0094] 14a Annular extension [0095] 14b Threaded hole [0096] 15 Bushing [0097] 15a Circumferential wall [0098] 16 Permanent magnet [0099] 17a Outer bearing [0100] 17b Inner bearing [0101] 18a Stator ring [0102] 18b Bushing ring [0103] 19 cable outlet [0104] 20 Roller [0105] 21 Roller core [0106] 22 Jacket layer [0107] 23 Engaging element [0108] 24 Running surface [0109] 25 Gap [0110] 26 Radial flange [0111] 27 Receiving element [0112] 28 Winding [0113] 29 Winding core [0114] 30 Retaining plate [0115] 31 Ventilation opening [0116] 32 Fastening hole [0117] 33 Ventilation space