Independent driving device for electric vehicle

Abstract

An independent driving device for an electric vehicle according to an embodiment of the present invention comprises: a steering arm for aligning a wheel according to a steering direction of an electric vehicle; a motor installed on the steering arm; a decelerator installed on the steering arm and connected to a motor shaft of the motor to control and output a rotation speed or a torque ratio of the motor; a hub carrier provided to face the decelerator and rotatably supporting the wheel; and an output transmission part connecting the decelerator and the hub carrier so that an output of the decelerator is transmitted to the hub carrier.

Description

Independent drive system for electric vehicles

[0001] The present invention relates to an independent motor device for an electric vehicle, and more particularly, to an independent motor device for an electric vehicle that independently provides driving force to each wheel of the electric vehicle.

[0002] As interest and awareness of environmental issues grow, demand for environmental performance in automobiles, along with carbon neutrality, is also increasing. Reflecting this demand, the automotive industry is shifting from internal combustion engine vehicles to electric vehicles. The sales and distribution of electric vehicles (EVs) in the global automotive market are increasing annually. Electric vehicles are sold and distributed in a variety of drive systems, including hybrid electric vehicles (HEVs), mild hybrid electric vehicles (MHEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and hydrogen fuel cell electric vehicles (FCEVs).

[0003] As sales and adoption of electric vehicles increase, various types of electric motors are being developed and applied to vehicles. Among these, in-wheel motors are attracting attention due to their superior space utilization in vehicle design, lowering the vehicle's center of gravity, and reducing vehicle weight.

[0004] In-wheel motors, mounted on each wheel of an electric vehicle, free up space previously reserved for powertrain components like engines for other uses. They also eliminate the need for powertrain components like transmissions and differentials, thereby reducing vehicle manufacturing costs. Furthermore, electric vehicles equipped with in-wheel motors benefit from reduced weight, as they require fewer parts.

[0005] However, in-wheel motors are installed directly on the wheels, which inevitably experience road shock. Furthermore, because they are installed within the confined space of the wheel, in-wheel motors are manufactured with a complex intertwining of mechanical and electronic components, such as motor windings and supporting ball bearings.

[0006] If road shock and vibration are directly transmitted to the in-wheel motor, the motor is vulnerable to road shock and is more likely to break or malfunction. Breakage or malfunction of the in-wheel motor can lead to loss of steering control in the electric vehicle, threatening the lives of the driver and passengers. Due to these issues, in-wheel motors are not widely used in electric vehicles.

[0007] Therefore, there is a need for a motor that has the advantages of an in-wheel motor while also ensuring durability and stability against road shocks.

[0008] Unless otherwise indicated herein, the matters described in this identifier are not prior art to the claims of this application, and their description in this identifier is not intended to be deemed prior art.

[0009] The problem to be solved by the present invention is to provide an independent motor device for an electric vehicle that ensures durability and stability against road shock and road vibration.

[0010] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] According to an embodiment of the present invention for solving the above problem, an independent driving device for an electric vehicle includes a steering arm for aligning the wheel according to the steering direction of the electric vehicle, a motor installed on the steering arm, a reducer installed on the steering arm and connected to a motor shaft of the motor to adjust and output a rotational speed or torque ratio of the motor, a hub carrier provided to face the reducer and rotatably support the wheel, and an output transmission unit connecting the reducer and the hub carrier such that the output of the reducer is transmitted to the hub carrier.

[0012] Other specific details of the present invention are included in the detailed description and drawings.

[0013] According to embodiments of the present invention, at least the following effects are achieved.

[0014] The present invention can reduce the possibility of damage or malfunction of the motor and reducer by forming a structure in which the motor and reducer are not directly affected by road impact.

[0015] The present invention has the advantage of further reducing the possibility of damage and malfunction of the motor and reducer by including a configuration that reduces road shock.

[0016] The present invention can improve the space utilization of an electric vehicle by minimizing the space in which a motor and reducer of an electric vehicle are installed.

[0017] The present invention has the effect of stably transmitting the output of the motor even when vibration occurs due to the curvature of the road surface.

[0018] The effects according to the present invention are not limited to those exemplified above, and more diverse effects are included in this specification.

[0019] FIG. 1 is a perspective view showing an independent driving device for an electric vehicle according to an embodiment of the present invention installed on a wheel of the electric vehicle.

[0020] Figure 2 is a perspective view of an independent driving device for an electric vehicle according to one embodiment of the present invention.

[0021] Figure 3 is a perspective view viewed from a different direction than Figure 2.

[0022] Figure 4 is an exploded perspective view of Figure 2;

[0023] Fig. 5 is a drawing showing a state in which the steering arm of Fig. 2 aligns the wheels of an electric vehicle.

[0024] Figure 6 is a state diagram showing the pivot arm of Figure 4 rotating.

[0025] Fig. 7 is a drawing showing a state in which the motor and reducer of Fig. 4 are placed on the steering arm.

[0026] FIG. 8 is a state diagram illustrating an independent driving device for an electric vehicle according to an embodiment of the present invention in a driving state of an electric vehicle.

[0027] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the scope of the claims.

[0028] Furthermore, the embodiments described herein will be described with reference to cross-sectional and / or schematic drawings, which are ideal illustrations of the present invention. Therefore, the form of the illustrations may be modified due to manufacturing techniques and / or tolerances. Furthermore, in each drawing illustrated in the present invention, each component may be depicted somewhat enlarged or reduced for convenience of explanation. Throughout the specification, the same reference numerals denote the same components.

[0029] Hereinafter, the present invention will be described with reference to drawings for explaining an independent driving device (10) for an electric vehicle according to an embodiment of the present invention.

[0030] FIG. 1 is a perspective view showing an independent driving device for an electric vehicle according to an embodiment of the present invention installed on a wheel of the electric vehicle, FIG. 2 is a perspective view of an independent driving device for an electric vehicle according to an embodiment of the present invention, FIG. 3 is a perspective view viewed from a different direction from FIG. 2, and FIG. 4 is an exploded perspective view of FIG. 2.

[0031] Referring to FIGS. 1 to 4, an independent driving device (10) for an electric vehicle according to an embodiment of the present invention includes a steering arm (100), a motor (200), a reducer (300), a hub carrier (400), and a power transmission unit (500). The independent driving device (10) for an electric vehicle according to an embodiment of the present invention may further include a buffer member (600) and a pivot arm (700).

[0032] The steering arm (100) aligns the wheels (WH) according to the steering direction of the electric vehicle, and is installed on each wheel (WH) of the electric vehicle. Fig. 5 is a drawing illustrating a state in which the steering arm of Fig. 2 aligns the wheels of the electric vehicle. Referring to Fig. 5, the steering arm (100) aligns the wheels (WH) by rotating along the steering direction. The electric vehicle can move in a straight line or in a curved direction by aligning the wheels (WH) by the steering arm (100).

[0033] Referring back to FIGS. 1 to 4, the steering arm (100) may include a first arm body (110) and a second arm body (120). The first arm body (110) is a portion where a motor (200) and a reducer (300) are installed, and may rotate along with the first arm body (110). The first arm body (110) may be installed in an electric vehicle in a vertical or nearly vertical form with respect to the ground. One end of the first arm body (110) may be positioned somewhat apart from the ground, and the other end may be connected to the second arm body (120) and may be positioned somewhat higher than the upper portion of a wheel (WH) of the electric vehicle. The motor (200) and the reducer (300) may be installed adjacent to one end of the first arm body (110).

[0034] The first arm body (110) may include a base portion (111), a first side wall portion (112), and a second side wall portion (113). The base portion (111) may be formed in a plate shape as a portion forming the body of the first arm body (110). The first side wall portion (112) and the second side wall portion (113) may extend from both longitudinal edges of the base portion (111) and may extend in a direction facing the outer surface of the wheel (WH). That is, the first arm body (110) may include the base portion (111), the first side wall portion (112), and the second side wall portion (113), and thus may have an accommodation space (114) that is open in a direction facing the wheel (WH).

[0035] A motor (200) and a reducer (300) may be installed in the first arm body (110). FIG. 7 is a drawing showing a state in which the motor and reducer of FIG. 4 are arranged on the steering arm. Referring to FIG. 7, the motor (200) and the reducer (300) may be accommodated and installed in the accommodation space (114) of the first arm body (110). Either the motor (200) or the reducer (300) may be installed in the accommodation space (114) of the first arm body (110), or both the motor (200) and the reducer (300) may be accommodated and installed. The motor (200) or the reducer (300) accommodated in the accommodation space (114) of the first arm body (110) may be protected from the external environment by the base portion (111), the first side wall portion (112), and the second side wall portion (113). In the drawing, the reducer (300) is installed in the receiving space (114) of the first arm body (110), and the motor (200) is installed in the first side wall (112).

[0036] The second arm body (120) extends from the other end of the first arm body (110) toward the direction in which the outer surface of the wheel (WH) faces, and is a part that is connected to another component responsible for steering the electric vehicle. The second arm body (120) can be installed in the electric vehicle in a horizontal or nearly horizontal form with respect to the ground. The second arm body (120) is positioned higher than the upper part of the electric vehicle. One end of the second arm body (120) can be connected or coupled to another component of the electric vehicle, and the other end can be connected to the first arm body (110). The second arm body (120) rotates along with the first arm body (110) according to the steering of the electric vehicle, and a rotational axis that serves as the center of the rotation passes through the second arm body (120).

[0037] The second arm body (120) can be formed in a similar shape to the first arm body (110) including the aforementioned base portion (111), first side wall portion (112), and second side wall portion (113). When the first arm body (110) and the second arm body (120) are formed in this shape, weight reduction and reduction in production cost are possible.

[0038] The motor (200) includes a motor shaft and generates rotational force to rotate a wheel (WH), and can transmit the rotational force to a reducer (300) through the motor shaft. The motor (200) can be installed together with the reducer (300) at a position adjacent to one end of the first arm body (110). Unlike a conventional in-wheel motor, the motor (200) is not installed on the wheel (WH) but on the steering arm (100). More precisely, since the motor (200) is installed on the first arm body (110) of the steering arm (100), it can avoid being directly exposed to road shock. In addition, since the road shock is attenuated by the buffer member (600), the motor (200) installed on the first arm body (110) can be safely protected from road shock. The motor (200) may be installed in the receiving space (114) of the first arm body (110), or may be installed in a location other than the receiving space (114). The motor (200) may be installed in the first arm body (110) in various ways, such as by bolting or pin fastening. When the motor (200) is installed in the receiving space (114) of the first arm body (110), it may be installed on any one of the inner surface of the base portion (111) of the first arm body (110), the inner surface of the first side wall portion (112), and the inner surface of the second side wall portion (113). When the motor (200) is installed in a location other than the receiving space (114) of the first arm body (110), it may be installed on any one of the outer surface of the base portion (111), the outer surface of the first side wall portion (112), and the outer surface of the second side wall portion (113).

[0039] Referring to Fig. 7, the motor (200) may be placed between one side and the other side of the steering arm (100) in consideration of the arrangement relationship with other parts, etc. One side of the steering arm (100) is a part where the upper pivot arm (710) is rotatably coupled, and the other side of the steering arm (100) is a part where the lower pivot arm (720) is rotatably coupled. Details related to this will be described later. The motor (200) may be installed in a space-efficient manner in conjunction with the output transmission unit (500) by being densely placed between one side and the other side of the steering arm (100).

[0040] The reducer (300) is connected to the motor shaft of the motor (200) and outputs by controlling the rotation speed or torque ratio of the motor (200). The reducer (300) can output by controlling the rotation speed or torque ratio of the motor (200) by connecting the internal gear to the motor shaft of the motor (200). The reducer (300) can be installed together with the motor (200) at a position adjacent to one end of the first arm body (110). Unlike the conventional in-wheel motor, the reducer (300) is not installed on the wheel (WH), but on the steering arm (100). Like the motor (200) described above, the reducer (300) is installed on the first arm body (110) of the steering arm (100), so that it is not directly exposed to road shock, or can be more safely protected from road shock by the buffer member (600).

[0041] Additionally, the reducer (300) may be placed on one side and the other side of the steering arm (100), similar to the motor (200). Space utilization can be increased by placing either the motor (200) or the reducer (300) between one side and the other side of the steering, or by placing both the motor (200) and the reducer (300).

[0042] The hub carrier (400) is provided to face the reducer (300) and rotatably supports the wheel (WH). The hub carrier (400) may include a carrier rotation part (410) and a carrier connection part (420).

[0043] The carrier rotation part (410) is a part that is directly connected to the wheel (WH) and rotates integrally with the wheel (WH), and the carrier connection part (420) is a part that is connected to the carrier rotation part (410) and is a part that is connected to the steering arm (100) or the pivot arm (700). The carrier rotation part (410) can be formed to be rotatable relative to the carrier connection part (420).

[0044] When the wheel (WH) moves up and down along the road surface curve, the carrier rotation part (410) and the carrier connection part (420) can also move up and down flexibly. This movement of the carrier rotation part (410) and the carrier connection part (420) can act as a road surface shock to the motor (200) and the reducer (300), but the road surface shock can be attenuated by the buffer member (600).

[0045] The output transmission unit (500) connected to the reducer (300) transmits the output of the reducer (300) to the hub carrier (400). Specifically, the reducer (300) can rotate the wheel (WH) by transmitting the output of the reducer (300) to the carrier rotation unit (410). The output transmission unit (500) can include a plurality of output shafts (510) and joints (520). When the output transmission unit (500) includes a plurality of output shafts (510) and joints (520), even if the position of the hub carrier (400) is displaced with respect to the reducer (300), the output of the reducer (300) can be transmitted. That is, even when the wheel (WH) moves up and down, the output of the reducer (300) can be transmitted to the carrier rotation unit (410). Referring to Fig. 4, the output transmission unit (500) is preferably composed of three output shafts (510) and two joints (520). The output transmission unit (500) can be implemented in various ways, including a universal joint, a constant velocity joint, etc., which are known types of shaft joints.

[0046] Meanwhile, the buffer member (600) supports the steering arm (100) and the hub carrier (400), and as the hub carrier (400) moves due to the movement of the wheel (WH), it can elastically expand and cushion road shock. One end of the buffer member (600) can be connected to the steering arm (100), and the other end of the buffer member (600) can be connected to the hub carrier (400). In order to efficiently cushion road shock, it is preferable that one end of the buffer member (600) be connected to the second arm body (120) of the steering arm (100), and the other end be connected to the carrier connection portion (420) of the hub carrier (400). The buffer member (600) can be implemented in various forms that elastically expand and cushion road shock, and the implementation form is not limited. For example, the buffer member (600) can be implemented to include a shock absorber and a coil spring.

[0047] And, the pivot arm (700) rotates in conjunction with the up-and-down movement of the wheel (WH) and the hub carrier (400), and one end may be rotatably coupled to the steering arm (100), and the other end may be rotatably coupled to the hub carrier (400). One end of the pivot arm (700) may rotate within a predetermined angular range around a portion coupled to the steering arm (100), and the other end of the pivot arm (700) may rotate within a predetermined angular range around a portion coupled to the hub carrier (400).

[0048] The joint structure of the pivot arm (700) and the steering arm (100), and the pivot arm (700) and the hub carrier (400) allows one end and the other end of the pivot arm (700) to rotate within a predetermined angular range according to the up-and-down movement of the wheel (WH) and the hub carrier (400), and can be implemented in various forms. For example, the joint structure of the pivot arm (700) and the steering arm (100), and the pivot arm (700) and the hub carrier (400) can be implemented in the form of an axial joint. That is, an axial joint portion (730) is formed at one end and the other end of the pivot arm (700), respectively, and corresponding axial joint portions (130, 430) can be formed at the steering arm (100) and the hub carrier (400), respectively. The corresponding axial joint portions (130, 430) have a form corresponding to the axial joint portion (730). The shaft coupling portion (730) and the corresponding shaft coupling portion (130, 430) can be coupled by a coupling shaft (SF).

[0049] Fig. 6 is a state diagram illustrating a state in which the pivot arm of Fig. 4 rotates. Referring to Fig. 6, the pivot arm (700) may include an upper pivot arm (710) and a lower pivot arm (720). The upper pivot arm (710) and the lower pivot arm (720) may be spaced apart from each other and arranged in parallel. One end of the upper pivot arm (710) may be rotatably coupled to one side of the steering arm (100), that is, one side of the first arm body (110), and the other end of the upper pivot arm (710) may be rotatably coupled to one side of the hub carrier (400), that is, one side of the carrier connecting portion (420). One end of the lower pivot arm (720) is rotatably coupled to the other end of the steering arm (100), that is, the other end of the first arm body (110), and the other end of the lower pivot arm (720) can be rotatably coupled to the other end of the hub carrier (400), that is, the other end of the carrier connecting portion (420). Since the pivot arm (700) includes the upper pivot arm (710) and the lower pivot arm (720), the load applied to the joint portion of the pivot arm (700) and the steering arm (100) and the joint portion of the pivot arm (700) and the hub carrier (400) is distributed. As the load is distributed, the risk of damage to the joint portion can be reduced. As described above, at least one of the motor (200) and the reducer (300) may be arranged between one side of the steering arm (100) to which one end of the upper pivot arm (710) is coupled and the other side of the steering arm (100) to which one end of the lower pivot arm (720) is coupled. Since the motor (200) and the reducer (300) are densely arranged between one side and the other side of the steering arm (100), the motor (200) and the reducer (300) can be installed in a space-efficient manner in connection with the output transmission unit (500).

[0050] Fig. 8 is a state diagram illustrating an independent driving device for an electric vehicle according to an embodiment of the present invention while the electric vehicle is in operation. Hereinafter, with reference to Fig. 8, the operating state of an independent driving device (10) for an electric vehicle according to an embodiment of the present invention while the electric vehicle is in operation will be briefly described.

[0051] An independent driving device (10) for an electric vehicle according to an embodiment of the present invention maintains a basic state in which the electric vehicle does not move up and down when the electric vehicle is stopped. When the electric vehicle starts to run in the basic state, the wheel (WH) begins to roll along the ground and moves up and down following the curvature of the ground. The movement of the wheel (WH) transmits road shock to the electric vehicle. When the wheel (WH) moves upward, the hub carrier (400) also moves upward as one unit with the wheel (WH). As the hub carrier (400) moves upward, the pivot arm (700) rotates at a predetermined angle, and the buffer member (600) is compressed to buffer the road shock. Conversely, when the wheel (WH) moves downward, the hub carrier (400) also moves downward as one unit with the wheel (WH). As the hub carrier (400) moves downward, the pivot arm (700) rotates at a predetermined angle and the buffer member (600) is tensioned to buffer the road shock.

[0052] As described above, the independent driving device (10) for an electric vehicle according to an embodiment of the present invention forms a structure in which the motor (200) and the reducer (300) are not directly exposed to road shock, thereby reducing the possibility of damage and malfunction of the motor (200) and the reducer (300). In addition, the present invention has the advantage of further reducing the possibility of damage and malfunction of the motor (200) and the reducer (300) by including a configuration that attenuates road shock. In addition, the present invention can improve the space utilization of the electric vehicle by minimizing the space in which the motor (200) and the reducer (300) of the electric vehicle are installed. In addition, the present invention has the effect of stably transmitting the output of the motor (200) even when vibration occurs due to the curvature of the road surface.

[0053] Although the preferred embodiments of the present invention have been described with reference to the attached drawings, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application. Therefore, the embodiments described above should be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the claims described below rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A steering arm that aligns the wheels according to the steering direction of the electric vehicle; A motor installed on the above steering arm; A reducer installed on the steering arm and connected to the motor shaft of the motor to control and output the rotation speed or torque ratio of the motor; A hub carrier which is provided to face the above reducer and rotatably supports the wheel; and An independent driving device for an electric vehicle, comprising: an output transmission unit connecting the reducer and the hub carrier so that the output of the reducer is transmitted to the hub carrier.

2. In paragraph 1, An independent driving device for an electric vehicle, further comprising a buffer member that supports the steering arm and the hub carrier and elastically expands and absorbs road shock as the hub carrier flows due to the movement of the wheel.

3. In paragraph 2, The above steering arm A first arm body in which the above motor and the above reducer are installed; and Including a second arm body extending in the direction in which the outer surface of the wheel is facing the first arm body; An independent driving device for an electric vehicle, wherein the above-mentioned buffer member is connected at one end to the second arm body and at the other end to the hub carrier.

4. In paragraph 1, An independent driving device for an electric vehicle, further comprising a pivot arm, one end of which is rotatably connected to the steering arm and the other end of which is rotatably connected to the hub carrier.

5. In paragraph 4, The above pivot arm is, An upper pivot arm, one end of which is rotatably connected to one side of the steering arm and the other end of which is rotatably connected to one side of the hub carrier; and An independent driving device for an electric vehicle, comprising: a lower pivot arm, one end of which is rotatably connected to the other end of the steering arm, and the other end of which is rotatably connected to the other end of the hub carrier.

6. In paragraph 5, An independent driving device for an electric vehicle, wherein at least one of the motor and the reducer is disposed between one side and the other side of the steering arm.

7. In paragraph 3, The above first arm body bass section; Including first and second side wall portions extending from both longitudinal edges of the base portion toward the direction in which the outer surface of the wheel is facing; An independent driving device for an electric vehicle, wherein at least one of the motor and the reducer is placed in a receiving space formed by the base portion and the first and second side wall portions.

8. In paragraph 1, The above output transmission unit is an independent drive device for an electric vehicle in which the output of the reducer is transmitted even if the hub carrier is displaced with respect to the reducer.

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