Electric moving device

Abstract

The utility model relates to an electric moving device. The electric moving device comprises a direct current motor assembly. The direct current motor assembly comprises a stator; a rotor rotatably disposed in the stator, the rotor including a commutator; a first brush (9a) and a second brush (9b) fixedly arranged relative to the rotor and configured to cooperate with the commutator when the rotor rotates; a first cable (11a) and a second cable (11b), the first cable being connected to the first brush (9a) and the second cable being connected to the second brush (9b); an electrically conductive motor housing (13) housing the stator, the rotor, the first and second brushes and the first and second cables; and an electromagnetic interference filter unit including a printed circuit board (15a) having a first ground plane (15b) electrically connected to the motor housing, and a capacitor (19) mounted on the printed circuit board.

Description

Technical Field

[0001] The utility model relates to an electric moving device such as an electric wheelchair. Background Art

[0002] The electric moving device can be driven by a direct current (dc) motor. In addition, in some cases, the moving device can include one or more actuators, for example, to operate a seat driven by a corresponding dc motor.

[0003] The DC motor has a rotor provided with electromagnets which are fed with a direct current via fixed brushes which are in electrical contact with a commutator fixed to the rotor shaft and electrically connected to the rotor windings.

[0004] The interaction between the rotating commutator and the stationary brushes can generate sparks, which can cause electromagnetic interference (EMI) problems. Utility Model Content

[0005] Electromagnetic interference filters can be used to reduce EMI problems. Such filters can include one or more capacitors or inductors and capacitors in an LC filter configuration. Ferrite materials can also be used to reduce electromagnetic radiation. However, none of these solutions may be effective enough or, as in the case of ferrite materials, may require a large amount of ferrite blocks.

[0006] In view of the above, a general object of the present invention is to provide an electric mobile device that solves or at least alleviates the problems of the prior art.

[0007] Therefore, an electric mobile device is provided, which includes a DC motor assembly, the DC motor assembly including: a stator; a rotor, the rotor is rotatably arranged in the stator, the rotor includes a commutator; a first brush and a second brush, the first brush and the second brush are fixedly arranged relative to the rotor, the first brush and the second brush are configured so that, when the rotor rotates, the first brush and the second brush cooperate with the commutator; a first cable and a second cable, the first cable is connected to the first brush, and the second cable is connected to the second brush; a conductive motor housing, the conductive motor housing accommodating the stator, the rotor, the first brush and the second brush, and the first cable and the second cable; and an electromagnetic interference filter unit, the electromagnetic interference filter unit including a printed circuit board, a capacitor, the printed circuit board having a first ground layer electrically connected to the motor housing, the capacitor is mounted on the printed circuit board and has a first terminal electrically connected to the first cable, a second terminal electrically connected to the second cable, and a third terminal electrically connected to the first ground layer.

[0008] The use of three or more terminal capacitors with a third or ground terminal has been found to be very effective in reducing radiated emissions. The use of a printed circuit board further simplifies mounting.

[0009] According to one embodiment, the capacitor comprises a fourth terminal electrically connected to the first ground layer.

[0010] The printed circuit board may be mounted against an end bell wall of the motor housing.

[0011] According to one embodiment, the printed circuit board includes a second ground layer, wherein the first ground layer is a first exposed layer of the printed circuit board disposed on a first side of the printed circuit board, and the second ground layer is a second exposed layer of the printed circuit board disposed on a second side of the printed circuit board facing the motor housing, and wherein the printed circuit board includes a plurality of vias electrically connecting the first ground layer with the second ground layer.

[0012] The via provides a low impedance electrical contact between the capacitor and the motor housing.

[0013] For example, the printed circuit board may include at least 10 (eg, at least 20, at least 30, or at least 40) vias.

[0014] According to one embodiment, the electric mobility device comprises a fastener, wherein the fastener extends through a metallized through-opening in the printed circuit board and presses the second ground layer against the motor housing.

[0015] The fastener may be a screw.

[0016] The fastener ensures that the entire second ground plane is in full mechanical contact with the motor housing, and thus in electrical contact with the motor housing, or in the case of a conductive filler, as will be described in more detail herein, in electrical contact with the conductive filler.

[0017] According to one embodiment, the motor housing has a flat surface against which the printed circuit board is mounted.

[0018] According to one example, the printed circuit board may be flexible such that when attached to the motor housing it follows the curvature of the motor housing.

[0019] According to one embodiment, the electric mobile device includes a conductive filler having a curved first surface and a flat second surface, the curved first surface being arranged to be in mechanical contact with the motor housing, the shape of the curved first surface following the curvature of the motor housing, wherein the printed circuit board is mounted on the flat second surface.

[0020] According to one embodiment, the printed circuit board is arranged inside the motor housing.

[0021] The conductive filler may have a convex surface abutting against an inner surface of the motor housing.

[0022] Alternatively, the printed circuit board may be mounted to the outer surface of the motor housing or to the conductive filler, which may be attached to the outer surface of the motor housing.The conductive filler may have a concave surface that abuts against the outer surface of the motor housing.

[0023] According to one embodiment, the first cable and the second cable extend through respective cable through-openings in the printed circuit board.

[0024] According to one embodiment, the capacitor is a multilayer ceramic capacitor.

[0025] According to one embodiment, the capacitor is Capacitor.

[0026] According to one embodiment, the electric mobility device is an electric wheelchair.

[0027] Generally, all terms used in the claims should be interpreted according to their ordinary meaning in the technical field, unless otherwise expressly defined herein. Unless otherwise expressly stated, all references to "element, device, component, means, etc." should be openly interpreted as referring to at least one instance of the element, device, component, means, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specific implementation of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0029] Figure 1 schematically illustrates a cross section of an example of a DC motor assembly;

[0030] Figure 2 An example of an EMI filter unit for a DC motor assembly is shown;

[0031] Figure 3A Depicts the Figure 2 A view of the AA section in FIG.

[0032] Figure 3B It is along Figure 2 A view of the BB section in FIG.

[0033] Figure 4 is another example of an EMI filter unit; and

[0034] Figure 5 is a side view of an example of a mobile device. DETAILED DESCRIPTION

[0035] The concepts of the present invention will now be described more fully below with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the concepts of the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided by way of example, so that the present invention will be thorough and complete and will fully convey the scope of the concepts of the present invention to those skilled in the art. Throughout the description, the same reference numerals represent the same elements.

[0036] Figure 1 A cross section of an example portion of a DC motor assembly 1 for an electric mobility device (eg, an electric wheelchair) is shown.

[0037] The DC motor assembly 1 includes a stator (not shown) and a rotor 3 .

[0038] The rotor 3 is rotatably arranged in the stator. The rotor 3 is arranged to electromagnetically interact with the stator.

[0039] The rotor 3 includes a rotor shaft 5 and an electromagnet including a rotor winding mounted on the rotor shaft 5 .

[0040] The rotor 3 comprises a commutator 7. The commutator is electrically connected to the rotor windings.

[0041] The DC motor assembly 1 includes a first brush 9a and a second brush 9b, which are arranged to be in direct mechanical contact with the commutator 7. The first brush 9a and the second brush 9b are configured to cooperate with the commutator 7 when the rotor 3 rotates.

[0042] The DC motor assembly 1 includes a first cable 11 a electrically connected to the first brush 9 a and a second cable 11 b electrically connected to the second brush 9 b .

[0043] The first cable 11a is arranged to be connected to a first pole, for example the positive pole, of a DC power source, and the second cable 11b is arranged to be connected to a second pole, for example the negative pole, of the DC power source.

[0044] When the rotor 3 is rotating, the polarity of the voltage from the first brush 9a, the second brush 9b to the commutator and thus to the rotor winding is alternately changed.

[0045] The DC motor assembly 1 comprises a conductive motor housing 13. For example, the motor housing 13 may be made of metal or a conductive cross-linked polymer material.

[0046] The stator, the rotor 3 , the commutator 7 , the first brush 9 a , the second brush 9 b , the first cable 11 a , and the second cable 11 b are arranged inside the motor housing 13 .

[0047] The motor housing 13 may have a circular or substantially circular cross-sectional shape along its inner periphery.

[0048] Furthermore, the DC motor assembly 1 further includes an electromagnetic interference (EMI) filter unit 15. The EMI filter unit 15 is configured to reduce electromagnetic radiation from the DC motor assembly 1.

[0049] Figure 2 Shows Figure 1 A close-up view of the EMI filter unit 15 is shown in FIG.

[0050] The EMI filter unit 15 includes a printed circuit board (PCB) 15 a .

[0051] The PCB 15a has a first side defining a first ground layer 15b. The first ground layer 15b is an exposed layer that forms the outermost surface of the PCB 15a at the first side.

[0052] The PCB 15a has a second side opposite to the first side. The second side defines a second ground layer 15c. The second ground layer 15c is an exposed layer facing the motor housing 13.

[0053] The first ground layer 15b and the second ground layer 15c form a ground plane.

[0054] The first ground layer 15b and the second ground layer 15c are electrically connected.

[0055] The PCB 15a comprises a metallized through opening 15d extending through the PCB 15a from the first side to the second side. Thus, the metallized through opening 15d has an inner surface clad with metal.

[0056] The metallized through opening 15d is in electrical contact with the first ground layer 15b and the second ground layer 15c.

[0057] The metallized through-opening 15d may be screwed.

[0058] The DC motor assembly 1 comprises a fastener 17a, 17b which is arranged in a respective one of the metallized through-openings 15d. The fastener 17a, 17b is electrically conductive. For example, the fastener 17a, 17b may be made of metal.

[0059] For example, the fasteners 17 a , 17 b may be metal screws that may engage with the threaded metallized through-openings 15 d and / or with the motor housing 13 .

[0060] According to this example, the fasteners 17a, 17b extend through the metallized through-opening 15d and into the motor housing 13. Thus, the first ground layer 15b and the second ground layer 15c are in electrical contact with the motor housing 13 via the fasteners 17a, 17b.

[0061] The DC motor assembly 1 may include a flexible element such as a spring washer disposed between the fastener head and the first ground plane 15b. This ensures that the fasteners 17a, 17b press the PCB 15a toward the motor housing 13 over time by thermal cycles that cause expansion and contraction of the components of the EMI filter unit 15.

[0062] The PCB 15a includes a cable through-opening for passing a corresponding one of the first cable 11a and the second cable 11b. The motor housing 13 also includes a through-opening aligned with a corresponding one of the cable through-openings of the PCB 15a. Thus, the first cable 11a and the second cable 11b are led out from the motor housing 13. The first cable 11a and the second cable 11b can be soldered to the PCB 15a.

[0063] Furthermore, the EMI filter unit 15 further includes a capacitor 19. The EMI filter unit 15 may include a single capacitor 19 or a plurality of capacitors 19 connected in series and / or in parallel.

[0064] The capacitor 19 is a surface mounted capacitor. The capacitor 19 may be soldered to the PCB 15a.

[0065] The capacitor 19 may be a multilayer ceramic capacitor.

[0066] Preferably, capacitor 19 may be Capacitor.

[0067] The capacitor 19 has a first terminal electrically connected to the first cable 11a and a second terminal electrically connected to the second cable 11b. The capacitor 19 also includes a third terminal electrically connected to the first ground layer and thus electrically connected to the motor housing 13.

[0068] The capacitor 19 may include a fourth terminal electrically connected to the first ground layer 15 b .

[0069] according to Figure 2 In the example shown in , the EMI filter unit 15 is arranged on the inner side of the motor housing 13 .

[0070] according to Figure 2 In the example shown in FIG. 1 , the DC motor assembly 1 includes a conductive filler 21. For example, the filler 21 may be made of metal or a conductive polymer material. The filler 21 has a curved first surface 21a having a shape that follows the curvature of the motor housing. Figure 2 In the example in FIG. 1 , the first surface 21 a follows the curvature of the inner surface of the motor housing 13 . The first surface 21 a is convex. The first surface 21 a is arranged in mechanical contact with the motor housing 13 .

[0071] The filler 21 has a flat second surface 21 b. The PCB 15 a is mounted to the flat second surface 21 b. The fasteners 17 a, 17 b press the PCB 15 a against the flat second surface 21 b and press the curved first surface 21 a against the inner surface of the motor housing 13 .

[0072] According to a variant, the motor housing 13 may be provided with a flat surface, such as a flat inner surface, to which the PCB 15a is mounted. In this case, no filler is required.

[0073] Figure 3A PCB 15a is along Figure 2 1. A cross-sectional view of line AA in FIG. 1 is shown. In particular, a first side with a first ground layer 15b is shown. A first terminal 19a, a second terminal 19b, a third terminal 19c, and a fourth terminal 19d of a capacitor 19 are visible. PCB 15a includes a plurality of vias 23 that extend through PCB 15a and electrically connect the first ground layer 15b to the second ground layer 15c. For example, the vias 23 may be evenly distributed along the outer periphery of PCB 15a.

[0074] Figure 3B PCB 15a is along Figure 2 A cross-sectional view along line BB in FIG.

[0075] Figure 4 A variation of a DC motor assembly 1 with an EMI filter unit 15 similar to the above-described EMI filter unit 15 is described. However, according to this example, the EMI filter unit 15' is mounted to the outer surface of the motor housing 13 via a conductive filler 21'. The curved first surface 21a' is pressed against the outer surface of the motor housing 13. The first surface 21a' is concave. Alternatively, the motor housing 13 may have an outer surface portion that is planar, and in this case, the PCB may be mounted directly to the outer surface portion without a filler.

[0076] Figure 5 An example of an electric moving device 25 is shown.

[0077] For example, the electric mobility device 25 may be an electric wheelchair.

[0078] The electric moving device 25 includes a driving wheel 27 .

[0079] The electric movement device 25 may include a seating system 29 and one or more actuators (not shown) arranged to change the position / state of the seating system 29 .

[0080] As described herein, the electric mobility device 25 includes one or more DC motor assemblies 1. For example, the DC motor assembly 1 can be configured to drive a corresponding drive wheel 27. According to some examples, the DC motor assembly 1 can be configured to drive an actuator for changing the position / state of the seating system 29.

[0081] The electric moving device 25 includes a battery (not shown). The first cable 11a and the second cable 11b of the DC motor assembly 1 may be directly or indirectly connected to the battery for feeding power to the first brush 9a and the second brush 9b, and thus to the rotor 3.

[0082] The concept of the invention has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than those disclosed above are equally possible within the scope of the inventive concept as defined by the appended claims.

Claims

1. An electric mobile device, characterized in that: The electric mobile device comprises: A DC motor assembly (1), the DC motor assembly comprising: stator, a rotor (3) which is rotatably arranged in the stator, the rotor (3) comprising a commutator (7), a first brush (9a) and a second brush (9b), the first brush and the second brush being fixedly arranged relative to the rotor (3), the first brush (9a) and the second brush (9b) being configured such that when the rotor (3) rotates, the first brush and the second brush cooperate with the commutator (7), a first cable (11a) and a second cable (11b), the first cable being connected to the first brush (9a), the second cable being connected to the second brush (9b), a conductive motor housing (13) accommodating the stator, the rotor (3), the first brush (9a) and the second brush (9b) and the first cable (11a) and the second cable (11b), and An electromagnetic interference filter unit, comprising a printed circuit board (15a), a capacitor (19), the printed circuit board having a first grounding layer (15b) electrically connected to the conductive motor housing (13), the capacitor being mounted on the printed circuit board (15a) and having a first terminal (19a) electrically connected to the first cable (11a), a second terminal (19b) electrically connected to the second cable (11b), and a third terminal (19c) electrically connected to the first grounding layer (15b).

2. The electric mobile device according to claim 1, characterized in that: The capacitor (19) includes a fourth terminal (19d) electrically connected to the first ground layer (15b).

3. The electric mobile device according to claim 1 or 2, characterized in that: The printed circuit board (15a) includes a second ground layer (15c), wherein the first ground layer (15b) is a first exposed layer of the printed circuit board (15a) disposed on a first side of the printed circuit board (15a), and the second ground layer (15c) is a second exposed layer of the printed circuit board (15a) disposed on a second side of the printed circuit board (15a) facing the conductive motor housing (13), and wherein the printed circuit board (15a) includes a plurality of vias (23) electrically connecting the first ground layer (15b) and the second ground layer (15c).

4. The electric mobile device according to claim 3, characterized in that: The electric mobile device comprises a fastener, wherein the fastener extends through a metallized through-opening (15d) in the printed circuit board (15a) and presses the second ground layer (15c) against the conductive motor housing (13).

5. The electric mobile device according to claim 1 or 2, characterized in that: The conductive motor housing (13) has a flat surface against which the printed circuit board (15a) is mounted.

6. The electric mobile device according to claim 1 or 2, characterized in that: The electric mobile device comprises a conductive filler having a curved first surface and a flat second surface, wherein the curved first surface is arranged to be in mechanical contact with the conductive motor housing (13), and the shape of the curved first surface follows the curvature of the conductive motor housing (13), wherein the printed circuit board (15a) is mounted on the flat second surface.

7. The electric mobile device according to claim 1, characterized in that: The printed circuit board (15a) is arranged inside the conductive motor housing (13).

8. The electric mobile device according to claim 1, characterized in that: The first cable (11a) and the second cable (11b) extend through corresponding cable through-openings in the printed circuit board (15a).

9. The electric mobile device according to claim 1, characterized in that: The capacitor (19) is a multilayer ceramic capacitor.

10. The electric mobile device according to claim 1, characterized in that: The capacitor (19) is Capacitor.

11. The electric mobile device according to claim 1, characterized in that: The electric mobility device is an electric wheelchair.

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