WO2022201173A1

WO2022201173A1 - An electrical machine

Info

Publication number: WO2022201173A1
Application number: PCT/IN2021/051171
Authority: WO
Inventors: Dhinagar Samraj Jabez; Aravindh Balaji VS; Subbiah Senthilnathan
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2021-03-23
Filing date: 2021-12-14
Publication date: 2022-09-29
Anticipated expiration: 2023-09-23

Abstract

The present invention discloses an electrical machine (100) with a wire routing member (301) having one or more holes (301A) for routing a set of wires (104) from the stator (201). The present invention achieves the objective of routing the set of wires (104) from the stator (201) without compromising the strength of the electrical machine (100).

Description

AN ELECTRICAL MACHINE

TECHNICAL FIELD

[0001] The present subject matter relates generally to an electrical machine of a vehicle. More particularly but not exclusively, the present subject matter relates to a wiring routing of the electrical machine of the vehicle.

BACKGROUND

[0002] A hub motor is an electrical machine that is incorporated in a hub of a wheel. The hub motor drives the wheel directly and has various advantages such as space saving on the vehicle body. Therefore, it is widely used in modem vehicles. The hub motor like a regular electrical machine includes a rotor, a stator, and a shaft. The rotating part of the hub motor i.e. the rotor is at the outer side while the stator is disposed at the inner side encompassed in the rotor. The shaft serves as an axle that is non-rotatably attached to a vehicle frame assembly at both ends. The stator is attached to the shaft, and the rotor is fixedly disposed of in the wheel. Hence, both the shaft and the stator stay static and non-rotational. Multiple permanent magnets are disposed circumferentially along an inner surface of the rotor. The stator comprises multiple teeth surrounded by metal windings, which get energized by electricity at each phase. Therefore, a rotational force is applied to the rotor having permanent magnets by a magnetic field generated by the energized stator windings. Thereafter, the rotation of the rotor is transmitted to drive the wheels of the vehicle. The stator windings get energized by an external electric source connected to the stator through a set of wires.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to refer to similar features and components.

[0004] Figure 1 exemplarily illustrates a general assembly of an electrical machine in accordance with one or more implementation.

[0005] Figure 2 exemplarily illustrates an exploded view of the electrical machine in accordance with one or more implementation [0006] Figure 3 (a) exemplarily illustrates a sub-assembly of an essential part of the electrical machine in accordance with one or more implementation [0007] Figure 3 (b) exemplarily illustrates a top view of a subpart of the electrical machine in accordance with one or more implementation

[0008] Figure 4 exemplarily illustrates a section view of the electrical machine in accordance with one or more implementation

DETAILED DESCRIPTION

[0009] An electrical machine of a vehicle includes a rotor, a stator, and a shaft. A hub motor is a kind of electrical machine, which is incorporated into the hub of a wheel. While in operation the rotor of the hub motor rotates at the outer side whereas the stator attached to the shaft remains static and non-rotational at an inner side. A set of wires from a plurality of winding of the stator connects the stator to an external power source. To energize the plurality of windings of the stator, electrical current is supplied to the stator windings through the set of wires. Since the set of wires connected to the hub motor are high voltage wires, hence it is important to keep the set of wires out of interference from any physical objects in its vicinity. Typically there is a need to route plurality of wires which include wires carrying high current as well as wires carrying signal e.g. controller signal or a sensor signal all of which need to be routed from the stator portion of the electrical machine towards various other aggregate systems of the vehicle e.g. to the control unit, energy source, etc. It is undesirable to club all such wires together into a conduit or casing and route them together as it can lead to undesirable electromagnetic interference adversely impacting the signal or current flowing through as well as making it difficult to assemble and service. In a combined and collective routing, any deterioration in single wire can cause damage to the entire cluster of harness leading to high cost of repair which is undesirable.

[00010] As per the known state of art, to prevent the set of wires from the undesirable interference of physical objects, the set of wires from the stator are passed through a cavity or an opening made in the shaft. However, the shaft with a cavity for passing the set of wires demands special sophisticated manufacturing and automated assembly thereby increasing the overall manufacturing cost and assembly time of the hub motor. A shaft with a cavity weakens the physical strength of the shaft thereby weakening the strength of the hub motor. Additionally, such an arrangement of wires projecting out of the shaft cavity eventually increases the overall diameter of the shaft with wires. The increased diameter of the shaft with wires leads to undesirable increase in an inner diameter of a bearing of the end cover which makes it difficult to remove the end cover for servicing. Further, such an arrangement of passing wires through the shaft cavity reduces the life of wires due to the rubbing of the wires with sharp end edges of the shaft. Furthermore, water sealing in the cavity of the shaft cannot be ensured thereby making the wires susceptible to water contact which can be catastrophic in nature.

[00011] Therefore, there exists a need for an electrical machine in which routing of the wires from the stator can be done without compromising the strength of the hub motor in a simple, and cost-effective manner and additionally which can effectively overcome the challenges of the known arts.

[00012] It is an object of the present invention to provide a wiring routing in an electrical machine, wherein the electrical machine comprises a rotor, a stator, and a shaft. The rotor of the electrical machine has a plurality of magnets disposed at the inner circumference. The stator comprises a plurality of teeth and one or more winding made of metals around said teeth. The shaft of the electrical machine being attached to the stator is a static and non-rotational member like the stator. The electrical machine is configured with a wire routing member attached to the shaft such that the wire routing member aids in routing the set of wires from the stator to the controller.

[00013] As per an aspect of the present invention, the wiring routing member comprises one or more opening capable of routing the set of wires from the stator. [00014] As per an aspect of the present invention, said one or more openings provided on the wire routing member are placed at a predetermined distance in an annular manner about the shaft axis. Therefore, the one or more openings in the wire routing member can be placed at an equidistant, attached, or non-equidistant distance from each other as per requirement. [00015] As per an aspect of the present invention, the one or more opening of the wire routing member have enough clearance between the wires and an inner periphery of said opening. A sealant in between the wires and the inner periphery of the one or more opening is disposed of for preventing the set of wires from being exposed to water droplets and also eliminating any entry of foreign contamination like mud, water from entering into the inside region of the electrical machine. [00016] As per yet another aspect of the present invention, the wire routing member is press-fitted on the shaft, thereby providing a simple and easy assembly for routing wires.

[00017] As per an embodiment of the present invention, a first inner bearing of a first end cover of the electrical machine at least partially and circumferentially overlaps with the wire routing member disposed on the shaft. The overlap of the first inner bearing on the wire routing member is configured such that the outer diameter of the shaft member including outer diameter of the wire routing member is substantially equal to or less than the inner diameter of the first inner bearing. [00018] As per yet another aspect of the present invention, the first inner bearing of the first end cover of the electrical machine is larger than the size of the second inner bearing of the second end cover of the electrical machine.

[00019] The present invention provides an electrical machine that efficiently and safely achieves the objective of routing wires in a simple, cost-effective manner without compromising on the strength of the electrical machine. Additionally, the present invention provides tailoring flexibility by adjusting the number of opening, size of opening and distance between said openings in the wire routing member as per requirement. The present invention also provides enough space for the disposition of the sealant in between the wires and the openings thereby preventing the set of wires from water droplets and other problems cited above.

[00020] The present subject matter is further described with reference to the accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[00021] Fig.l and Fig.2 exemplarily illustrates a general assembly perspective view and an exploded perspective view of a hub motor hereinafter referred to as an electrical machine (100), comprising a first end cover (101), a second end cover (102), a shaft (103), and a set of wire (104). As seen in Fig.2, the electrical machine (100) includes a rotor (202) encompassing a stator (201) which is coupled to the shaft (103). The rotor (202) rotates while the stator (201) is static and non-rotational along with the shaft (103). The rotor (202) comprises a plurality of magnets (202A) disposed circumferentially along an inner circumference of the rotor (202). The stator (201) comprises a plurality of teeth (201 A) surrounded by one or more windings (not labelled). The teeth (201 A) along with the stator gets assembled on the shaft (103). A set of wire (104) connects the stator (201) to a controller (not shown) to energize the one or more windings of the stator (201) at each phase. Since the first end cover (101) and the second end cover (102) both are moving parts rotating along with the rotor (202), it is impossible to take out the set of wires (104) from the end covers. Therefore, the only possible way of taking out the set of wires (104) from the motor is either through the shaft (103) or through near to the shaft (103).

[00022] Fig.3 (a) and Fig.3 (b) exemplarily illustrate sub-assembly and subpart of the electrical machine. The shaft (103) ofthe electrical machine (100) is configured with a wire routing member (301) assembled on it for routing the set of wires (104) from the stator (201). As per an embodiment, the wire routing member (301) is press-fitted on the shaft (103). The wire routing member (301) comprises one or more openings (301A) which aids in routing and supporting the set of wires (104). For example, the wire routing member (301) can comprise of four openings for holding three phase wires and one sensor wire. Therefore, tailoring of said wire routing member (301) can be done as per requirement. Additionally, the space between the one or more openings (301A) is predetermined. Space can be equidistant, non-equidistant, or attached on a case-to-case basis. Further, the one or more openings (301) are large enough to accommodate a sealant (not shown) between the set of wires (104) and an inner periphery (301AA) of the one or more openings (301A). The sealant prevents the one or more set of wires (104) from water droplets, entry of external contamination etc.

[00023] Fig.4 exemplarily illustrates a section view of the electrical machine (100) in accordance with one or more implementation. As can be seen from Fig. 4 the first end cover (101) and the second end cover (102) includes a first inner bearing (401 A) and a second inner bearing (40 IB) respectively. The first inner bearing (401 A) is configured to at least partially and circumferentially overlap with the wire routing member (301) in an axis direction of the shaft. The first inner bearing (401 A) has a bigger outer diameter Dio than the outer diameter D2o of the second inner bearing (40 IB) i.e. Dio > D2o. Thus a co-axial and static wire routing member (301) is configured on the inner diameter of the first bearing (401A) which enables transfer of the loads from the first bearing (401 A) onto the shaft (103) while also enabling rotary motion of the first end cover (101) The circumferential overlapping design of the first inner bearing (401 A) on the wire routing member (301) ensures that the outer diameter D4o of the shaft along with the outer diameter

D3o of the wire routing member (301) is substantially equal to the inner diameter Dli of the first inner bearing (401 A) diameter i.e. Dli = D3o and D3i = D4o This helps in passing the set of wires (104) after crossing the inner bearings (401 A) in a defined path, thereby providing ease of serviceability by removing the rotational end covers.

[00024] Many other improvements and modifications may be incorporated herein without deviating from the scope of the invention.

List of Reference numerals 100: Electrical machine 101: First end cover 102: Second end cover 103: Shaft

104: Set of wires 201: Stator

201 A: Plurality of teeth 202: Rotor 202A: Plurality of magnets

301: Wire routing member 301 A: One or more holes 301AA: Inner periphery 401 A: First inner bearing 40 IB: Second inner bearing

Claims

We claim:

1. An electrical machine (100) comprising a rotor (202) comprising a plurality of magnets (202A) disposed circumferentially along an inner circumference of the rotor (202); a stator (201) comprising a plurality of teeth (201 A), and one or more winding around each of the plurality of teeth (201 A); a shaft (103) attached to the stator (201); wherein a co-axial and static wire routing member (301) is configured to be attached to the shaft (103) on the outer diameter of the shaft.

2. The electrical machine (100) as claimed in claim 1, wherein the wire routing member (301) comprises one or more openings (301A) capable of routing a one or more wires (104) from the stator (201).

3. The electrical machine (100) as claimed in claim 2, wherein the one or more openings (301 A) being provided on the wire routing member (301) with a predefined circumferential space in between the openings.

4. The electrical machine (100) as claimed in claim 1, wherein the one or more openings (301 A) of the wire routing member (301) have clearance for holding a sealant (not shown) between the set of wires (104) passing through the one or more openings (301A) and an inner periphery (301AA) ofthe one or more openings (301A) of the wire routing member (301).

5. The electrical machine (100) as claimed in claim 1, wherein the wire routing member (301) is press-fitted on the shaft (103).

6. The electrical machine (100) as claimed in claim 1 or claim 2, wherein a first inner bearing (401 A) of a first end cover (101) ofthe electrical machine (100) at least partially and circumferentially overlaps the wire routing member (301) in a axis direction of the shaft.

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7. The electrical machine (100) as claimed in claim 1 or claim 2, wherein the diameter of the shaft (103) including the wire routing member (301) being equal to the diameter of the first inner bearing (401 A).

8. The electrical machine ( 100) as claimed in claim 6, wherein the first inner bearing (401A) of the first end cover (101) of the electrical machine (100) is larger in size than a second inner bearing (40 IB) of the of a second end cover (102) of the electrical machine (100) (Dio > D2o).

9. The electrical machine (100) as claimed in claim 6, wherein the outer diameter (D3o) of the wire routing member (301) is substantially equal to the inner diameter (Dli) of the first inner bearing (401 A) diameter.

10. The electrical machine (100) as claimed in claim 6, wherein the inner diameter of the shaft D3i is equal to outer diameter D4o of the shaft (103).

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