Motor for vehicle

Abstract

An embodiment of the present invention provides a motor for a vehicle, comprising: a shaft; a stator disposed as an annular shape about a rotor; a bearing which supports the shaft to be rotatable; a bearing support portion which supports the bearing; and a bearing damper which is disposed on the bearing support portion and comes into contact with the bearing, wherein the bearing damper absorbs vibrations transferred from the bearing and provides a preload to one side of the bearing in the axial direction.

Description

vehicle motors

[0001] The present invention relates to a motor for a vehicle.

[0002] In general, a motor is a device that converts electrical energy into rotational energy by utilizing the force that a conductor receives in a magnetic field.

[0003] As motor applications have expanded in recent years, their role has become increasingly important. In particular, with the rapid advancement of vehicle electrification, demand for motors used in steering and braking systems is growing significantly.

[0004] The motor comprises a shaft formed to be rotatable, a rotor coupled to the shaft, and a stator fixed inside the motor housing. The stator is installed along the circumference of the rotor with a gap. Furthermore, coils that form a rotating magnetic field are wound around the stator, causing electromagnetic interaction with the rotor to induce rotation of the rotor. As the rotor rotates, the shaft rotates, generating driving force.

[0005] Electric vehicles, which currently use electricity to charge, have much lower interior noise levels than conventional internal combustion engine vehicles, so the noise and vibration requirements of users, including drivers, are continuously expanding, and in particular, the noise and vibration requirements of motors are continuously strengthening.

[0006] As for the current motor, when assembling the rotor and stator, preload is applied to the ball bearings that support the shaft to reduce noise and vibration generated when the motor rotates.

[0007] To apply a preload to a ball bearing supporting a shaft, a wave washer may be conventionally used. For example, a wave washer may apply a preload to the outer ring of a ball bearing.

[0008] However, since the wave washer is made of metal, if axial shaking occurs during the rotation of the motor or the ball bearing is damaged, the shock is transmitted to the motor through the wave washer and directly to the vehicle interior, which has a negative impact on the driver's driving experience.

[0009] The purpose of the present invention is to provide a vehicle motor that can minimize noise and vibration and extend the life of ball bearings.

[0010] In addition, the purpose is to provide a vehicle motor capable of applying stable preload to a ball bearing.

[0011] In order to achieve the above-described purpose, a vehicle motor according to one embodiment of the present invention has a technical feature of minimizing noise and vibration and extending the life of the ball bearing by installing a bearing damper made of rubber material capable of uniformly providing preload to the outer ring of the ball bearing.

[0012] The present invention provides a vehicle motor comprising: a shaft; a rotor fixed to the shaft; a stator arranged in an annular shape around the rotor; a bearing that rotatably supports the shaft; a bearing support that supports the bearing; and a bearing damper arranged in the bearing support and in contact with the bearing, wherein the bearing damper absorbs vibration transmitted from the bearing and provides an axial preload to one side of the bearing.

[0013] The above bearing damper may be formed in an annular shape of rubber material.

[0014] According to an embodiment of the present invention, the inner ring of the bearing is press-fitted onto the shaft, and the outer ring of the bearing is supported by the bearing damper so that an axial preload can be applied.

[0015] According to an embodiment of the present invention, a groove may be provided on the outer surface of the outer ring of the bearing, and an O-ring inserted into the groove may be provided.

[0016] According to an embodiment of the present invention, the bearing damper may have a cross-section that is circular or rectangular and may have a uniform height.

[0017] According to an embodiment of the present invention, the bearing damper may have an outer diameter smaller than the outer diameter of the outer ring of the bearing, and an inner diameter of the bearing damper may be larger than the inner diameter of the outer ring of the bearing.

[0018] According to an embodiment of the present invention, a damper receiving groove may be formed on the bottom surface of the bearing support between the bearing and the bearing support.

[0019] According to an embodiment of the present invention, the inner diameter of the damper receiving groove increases from the top to the bottom, and the width of the inlet may be smaller than or equal to the diameter of the cross-section of the bearing damper.

[0020] According to an embodiment of the present invention, the width of the damper receiving groove may be greater than or equal to the diameter of the cross-section of the bearing damper.

[0021] According to an embodiment of the present invention, the inner diameter of the damper receiving groove may be larger than the inner diameter of the outer ring of the bearing.

[0022] According to an embodiment of the present invention, the upper height of the damper receiving groove can be formed higher than the center height of the bearing damper.

[0023] According to an embodiment of the present invention, the bearing may include a ball bearing.

[0024] According to the motor of the present invention having the configuration described above, by installing a bearing damper made of rubber that can uniformly provide preload to the outer ring of the ball bearing, noise and vibration can be minimized and the life of the ball bearing can be extended.

[0025] By restraining the bearing damper from being dislodged from the damper receiving groove of the bearing support, not only can poor installation of the bearing damper on the bearing support be prevented, but also a stable preload can be applied to the ball bearing.

[0026] Fig. 1 is a perspective view showing a motor according to an embodiment of the present invention.

[0027] Figure 2 is a cross-sectional view taken along line 'A-A' of Figure 1.

[0028] Fig. 3 is an enlarged cross-sectional view showing a bearing installation structure according to an embodiment of the present invention.

[0029] Fig. 4 is a perspective view showing a bearing damper according to an embodiment of the present invention.

[0030] FIG. 5 is a displacement graph showing the compression distance and compression force of a bearing damper according to an embodiment of the present invention.

[0031] FIG. 6 is a cross-sectional view showing a bearing support according to the first embodiment of the present invention, which is an enlarged view of part “A” of FIG. 2.

[0032] FIG. 7 is a cross-sectional view showing a bearing support according to a second embodiment of the present invention, which is an enlarged view of part “A” of FIG. 2.

[0033] FIG. 8 is a displacement graph showing the vibration and frequency of a wave washer according to an internal technology and a bearing damper according to an embodiment of the present invention.

[0034] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When designating components in the drawings, it should be noted that, where possible, identical components will be given the same reference numerals, even if they appear in different drawings. Furthermore, when describing embodiments of the present invention, detailed descriptions of related, known structures or functions will be omitted if they are deemed to hinder understanding of the embodiments of the present invention.

[0035] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of embodiments of the present invention. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms. When it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but another component may also be "connected," "coupled," or "connected" between each component.

[0036] Hereinafter, a motor (10) according to various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0037] FIG. 1 is a perspective view showing a motor (10) according to an embodiment of the present invention, and the motor (10) according to the embodiment may include a motor housing (100) and a cover (200).

[0038] Next, Fig. 2 is a cross-sectional view taken along line 'A-A' of Fig. 1.

[0039] The X direction illustrated in Fig. 2 may refer to a radial direction, and the Y direction may refer to an axial direction. In addition, the axial direction and the radial direction may be arranged perpendicular to each other.

[0040] Here, the axial direction may refer to the longitudinal direction of the shaft (500) described later.

[0041] In addition, the drawing symbol 'C' shown in FIG. 2 means the center of rotation, i.e. the center of the axis, and the direction along a circle having a radius in the radial direction based on the center of the axis can be said to be the circumferential direction.

[0042] Referring to FIG. 2, a motor (10) according to an embodiment may include a motor housing (100), a cover (200), a stator (300), a rotor (400), a shaft (500), a bearing (600), and a bus bar (700).

[0043] The motor housing (100) can accommodate a stator (300), a rotor (400), a shaft (500), a bearing (600), a bus bar (700), etc. inside. The motor housing (100) can include a cylindrical housing body (110).

[0044] The cover (200) covers the upper portion of the stator (300) and rotor (400) accommodated in the housing body (110) of the motor housing (100) and is coupled to the motor housing (100). The cover (200) may be formed in a cylindrical shape, similar to the motor housing (100).

[0045] The motor housing (100) and cover (200) form the outer shape of the motor (10), and an accommodation space can be formed inside the motor housing (100) and cover (200). Accordingly, a stator (300), a rotor (400), a shaft (500), a bus bar (700), and a bearing (600) can be placed in the accommodation space.

[0046] The motor housing (100) and cover (200) may be formed of, for example, aluminum, iron, or an alloy containing each of these. However, the present invention is not limited thereto, and various materials may be adopted and applied.

[0047] The motor (10) can install the stator (300) inside the motor housing (100) by hot pressing.

[0048] Here, the hot pressing method refers to a method of fixing the stator (300) and the like to an internal receiving space during a size change process through heating and cooling of the motor housing (100).

[0049] In detail, it refers to a method in which the motor housing (100) is heated to a predetermined temperature to expand the motor housing (100), and the size of the accommodation space of the motor housing (100) is temporarily expanded and increased, and then the stator (300) can be inserted.

[0050] As the motor housing (100) cools, the motor housing (100) shrinks and returns to its original state, thereby reducing the size of the motor housing (100). Accordingly, the motor housing (100) presses the inside of the stator (300), and the stator (300) can be fixed to the motor housing (100).

[0051] The stator (300) may include a stator core (310), an insulator (320), and a coil (330).

[0052] A coil (330) that forms a rotating magnetic field may be wound around the stator (300). Specifically, the coil (330) may be wound around the insulator (320) of the stator (300). The coil (330) may be wound around the stator (300) and may be supplied with an external power source. When an external power source is supplied to the coil (330), it causes an electromagnetic interaction with the rotor (400).

[0053] The stator core (310) may be formed by stacking multiple thin steel plates, but is not limited thereto, and may be formed as a single part.

[0054] The stator core (310) may include a cylindrical yoke portion (not shown) and a plurality of teeth portions (not shown) protruding from the yoke portion toward the center.

[0055] The insulator (320) insulates the stator core (310) and the coil (330). Therefore, the insulator (320) can be installed between the stator core (310) and the coil (330), and the coil (330) can be wound around the stator core (310) on which the insulator (320) is installed.

[0056] The rotor (400) may be placed inside the stator (300). The rotor (400) may have a shaft (500) coupled to its center. Here, the inner side may refer to a direction positioned toward the rotation center (C) of the motor (10) based on the radial direction, and the outer side may refer to a direction opposite to the inner side.

[0057] The rotor (400) may include a rotor core (410) and a magnet (420). The rotor core (410) may be formed in a shape in which a plurality of plates in the form of circular thin steel plates are laminated. A hole may be formed in the center of the rotor core (410) through which a shaft (500) passes and is coupled.

[0058] The rotor (400) can be formed by combining a plurality of magnets (420) to a rotor core (410). For example, the rotor (400) can have magnets (420) installed on the outer peripheral surface of the rotor core (410).

[0059] The magnet (420) forms a rotating magnetic field with the coil (330) wound around the stator core (310). The magnet (420) may be installed so that the N pole and the S pole are alternately positioned. Therefore, the rotor (400) rotates due to the electromagnetic interaction between the coil (330) and the magnet (420), and the shaft (500) rotates in conjunction with the rotation of the rotor (400), thereby generating driving force for the motor (10).

[0060] Here, the magnet (420) of the rotor (400) is also referred to as a drive magnet. The magnets (420) may be installed along the outer peripheral surface of the rotor core (410) at regular intervals.

[0061] The rotor (400) may include a can member (not shown) that prevents the magnet (420) from being separated from the rotor core (410) and prevents the magnet (420) from being exposed. In this case, the can member may be arranged to cover the rotor core (410) to which the magnet (420) is coupled.

[0062] The shaft (500) can be rotatably supported inside the motor housing (100) by a bearing (600).

[0063] The shaft (500) can be press-fitted into a hole formed in the center of the rotor core (410). The shaft (500) can be connected to a steering shaft of a vehicle and transmit power to the steering shaft.

[0064] The shaft (500) can be formed of a metal material having a predetermined rigidity.

[0065] The bearing (600) may be installed on the upper and lower portions of the shaft (500) depending on the installation location. The bearing (600) may include a first bearing (610) supporting the upper portion of the shaft (500) and a second bearing (620) supporting the lower portion of the shaft (500).

[0066] Additionally, the bearing (600) may include a housing bearing installed in the motor housing (100) and a cover bearing installed in the cover (200).

[0067] And the bearing (600) may include a ball bearing including an outer ring (601), an inner ring (602), and a ball (603) installed between the outer ring (601) and the inner ring (602). As the bearing (600) supports the outer circumference of the shaft (500), the shaft (500) can rotate within the receiving space of the motor housing (100).

[0068] The bus bar (700) may be placed on the upper portion of the stator (300) and may be supported by the insulator (320). The bus bar (700) may be electrically connected to the coil (330) of the stator (300). The bus bar (700) may be electrically connected to a power transmission device, such as an external connector, through a through hole perforated in the cover (200).

[0069] Meanwhile, according to an embodiment of the present invention, it is intended to provide a motor (10) with improved NVH performance by installing a bearing damper (900) that uniformly applies preload to a bearing (600).

[0070] FIG. 3 is a cross-sectional view showing an enlarged installation structure of a second bearing according to an embodiment of the present invention, FIG. 4 is a perspective view showing a bearing damper (900) according to an embodiment of the present invention, and FIG. 5 is a displacement graph showing a compression distance and compression force of a bearing damper (900) according to an embodiment of the present invention.

[0071] Referring to FIG. 3, a bearing support member (800) for fixing and supporting a second bearing (620) is provided at the center of the bottom of the motor housing (100).

[0072] The bearing support (800) has a cylindrical shape with an open upper portion, and the second bearing (620) among the bearings (600) can be inserted and supported through the open upper portion of the bearing support (800). That is, the second bearing (620) that supports the lower portion of the shaft (500) in the motor housing (100) can be supported by the bearing support (800).

[0073] Since the bearing support (800) must support the rotor (400) and shaft (500) that rotate at high speed, it is preferable to manufacture it from a metal material with excellent rigidity.

[0074] A bearing support (800) according to an embodiment of the present invention may include a structure for precisely aligning and supporting a shaft (500) of a motor (10) rotating at high speed. Accordingly, the bearing support (800) can be precisely designed for its position relative to the motor housing (100).

[0075] The inner ring (602) of the bearing (600) installed in the bearing support (800) can have its inner surface in contact with the outer surface of the shaft (500).

[0076] And the outer ring (601) of the bearing (600) installed in the bearing support (800) can have an outer circumferential surface in contact with the inner circumferential surface of the bearing support (800).

[0077] According to the present invention, the inner ring (602) of the bearing (600) is press-fitted to the shaft (500), and the outer ring (601) of the bearing (600) can be seated on the inside of the bearing support (800). A plurality of grooves (604) are formed on the outer circumferential surface of the outer ring (601) of the bearing (600). An O-ring (605) is provided in the plurality of grooves (604) to closely contact the inside of the bearing support (800) and seal it from the outside.

[0078] Between the outer ring (601) and the inner ring (602) of the bearing (600), a plurality of rolling members, i.e., balls (603), are interposed along the circumferential direction of the bearing (600) to support relative rotation between the outer ring (601) and the inner ring (602) of the bearing (600).

[0079] An elastic bearing damper (900) may be compressed and interposed between the bottom surface of the second bearing (620) provided at the lower portion of the motor housing (100) and the bottom surface of the bearing support member (800) to support the second bearing (620). For example, the bearing damper (900) may support the outer ring (601) of the second bearing (620).

[0080] Referring to FIG. 4, the bearing damper (900) is an annular elastic body made of a rubber damper body, and can apply a uniform preload to the outer ring (601) of the bearing (600).

[0081] When the outer ring (601) of the second bearing (620) is supported by an upward force by a bearing damper (900) like this, the force is transmitted to the inner ring (602) through the ball (603), and the inner ring (602) can apply a preload upward to the shaft (500).

[0082] In this way, the configuration in which the bearing damper (900) applies a preload to the bearing (600) is such that even if axial shaking occurs when the motor rotates or vibration occurs due to damage to the bearing (600), the embodiment can block vibration and reduce noise generation by applying a uniform preload to the outer ring (601) of the bearing (600) using the bearing damper (900) made of a rubber material.

[0083] And the bearing damper (900) may include a damper body having a cross-section having either a circular or rectangular shape.

[0084] For example, as shown in (a) of FIG. 4, the bearing damper (900) may include a damper body whose cross-section includes a circular shape. Also, as shown in (b) of FIG. 4, the second bearing damper (900b) may include a damper body whose cross-section includes a rectangular shape.

[0085] Referring to FIG. 5, the second bearing damper (900b) in the embodiment can obtain an upward linear graph in which the relationship between the compression force and the compression distance is proportional, which can be advantageous in terms of adjusting the preload.

[0086] Meanwhile, a bearing damper (900) with a circular cross-sectional structure can obtain a curved graph of an upward-sloping second-order equation.

[0087] Accordingly, a bearing damper (900) having a circular or square cross-sectional shape may be selected depending on the required preload for the bearing (600), but is not limited thereto.

[0088] The following example describes a bearing damper (900) having a circular cross-section, but is not limited thereto and can also be applied to a second bearing damper (900b) having a square cross-section.

[0089] The bearing damper (900) having the above cross-sectional structure can be formed in a shape that is smaller than the outer diameter of the outer ring (601) of the second bearing (620) and larger than the inner diameter. The inner diameter of the damper receiving groove (810) can also be formed in a shape that is larger than the inner diameter of the outer ring of the second bearing (620). For example, the outer diameter of the bearing damper (900) is smaller than the outer diameter of the outer ring (601) of the second bearing (620), and the inner diameter of the bearing damper (900) is larger than the inner diameter of the outer ring (601) of the second bearing (620), thereby effectively applying a preload to the outer ring (601) of the second bearing (620). That is, the upper part of the bearing damper (900) can contact the lower surface of the outer ring (601) of the second bearing (620) to apply preload in the axial direction of the shaft (500). Of course, the bearing damper (900) should not contact the inner ring (602) of the second bearing (620) that rotates together with the shaft (500) as much as possible.

[0090] Accordingly, a uniform preload can be applied to the outer ring (601) of the second bearing (620) by the bearing damper (900).

[0091] FIG. 6 is a cross-sectional view showing a bearing support according to a first embodiment of the present invention, which is an enlarged view of part “A” of FIG. 2, and FIG. 7 is a cross-sectional view showing a bearing support according to a second embodiment of the present invention, which is an enlarged view of part “A” of FIG. 2.

[0092] Referring to FIG. 6, a damper receiving groove (810) may be formed on the bottom surface of the bearing support (800) between the bearing (600) and the bearing support (800) in which a portion of the bearing damper (900) can be received. Specifically, a portion of a bearing damper (900) having a circular or rectangular cross-sectional shape may be received in the damper receiving groove (810) formed in the bearing support (800) to apply a preload to the bearing (600).

[0093] The width of the damper receiving groove (810) may be greater than or equal to the diameter of the cross-section of the bearing damper (900) to ensure accurate seating of the bearing damper (900).

[0094] Conversely, if the width of the damper receiving groove (810) is smaller than the diameter of the cross-section of the bearing damper (900), the bearing damper (900) may not be seated accurately in the damper receiving groove (810), and thus the bearing damper (900) may cause an imbalance in the preload with respect to the bearing (600).

[0095] Referring to Fig. 7, when the bearing damper (900) has a circular cross-sectional shape, the damper receiving groove (810) may be formed in a tapered shape with an inner diameter that increases from the top to the bottom. Here, the depth of the damper receiving groove (810) may be formed to be greater than the center height of the bearing damper (900). Accordingly, when the bearing damper (900) is fitted into the damper receiving groove (810), the bearing damper (900) can be received more stably.

[0096] As the bearing damper (900) is stably accommodated in the damper accommodation groove (810), it is possible to prevent improper installation of the bearing damper (900) on the bearing support (800) and to apply a constant preload to the outer ring (601) of the bearing (600).

[0097] FIG. 8 is a displacement graph showing vibration and frequency of a wave washer according to the prior art and a bearing damper according to an embodiment of the present invention.

[0098] Referring to FIG. 8, in the process of applying preload to a bearing (600) in a wave washer according to the prior art, mechanical disturbance is introduced into the wave washer, which may cause vibration in a specific frequency range (500 to 800 Hz), thereby causing noise.

[0099] However, the bearing damper (900) according to the present invention can reduce vibration and noise generation in a specific frequency range where vibration occurs due to the wave washer.

[0100] Therefore, according to the motor (10) according to the present invention, by installing a bearing damper (900) made of rubber that can uniformly provide a preload to the outer ring (601) of the bearing (600), the shock and vibration transmitted from the bearing (600) can be absorbed or blocked, thereby minimizing noise generation.

[0101] In addition, since a part of the bearing damper (900) is accommodated in the damper accommodation groove (810) of the bearing support (800), not only can the installation failure of the bearing damper (900) to the bearing support (800) be prevented, but also a stable preload can be applied to the outer ring (601) of the bearing (600).

[0102] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

[0103] The motor of the present invention can be applied to a vehicle.

Claims

1. Shaft; A rotor fixed to the above shaft; A stator arranged in a ring around the rotor; A bearing that rotatably supports the above shaft; A bearing support supporting the above bearing; and A bearing damper disposed on the bearing support and in contact with the bearing; A vehicle motor, wherein the bearing damper absorbs vibration transmitted from the bearing and provides axial preload to one side of the bearing.

2. In paragraph 1, As a first condition, the bearing damper is made of an annular rubber material, and As a second condition, the outer diameter of the bearing damper is smaller than the outer diameter of the outer ring of the bearing, and the inner diameter of the bearing damper is larger than the inner diameter of the outer ring of the bearing. A motor for a vehicle that satisfies at least one of the following conditions.

3. In paragraph 2, If the above second condition is satisfied, The inner ring of the bearing is press-fitted onto the shaft, and the outer ring of the bearing is supported on the bearing damper to receive axial preload. A motor for a vehicle, wherein a groove is provided on the outer surface of the outer ring of the bearing, and an O-ring is provided to be inserted into the groove.

4. In paragraph 1, At least a portion of the above bearing damper comprises a cross-section having a circular or rectangular shape, and The above bearing damper has a uniform height, A motor for a vehicle that satisfies at least one of the following conditions.

5. In paragraph 1, A motor for a vehicle, wherein a damper receiving groove is formed on the bottom surface of the bearing support between the bearing and the bearing support.

6. In paragraph 5, The inner diameter of the above damper receiving groove increases from the top to the bottom, and the width of the inlet is smaller than or equal to the diameter of the cross-section of the bearing damper. The width of the above damper receiving groove is greater than or equal to the diameter of the bearing damper cross-section, and The inner diameter of the above damper receiving groove is larger than the inner diameter of the outer ring of the above bearing, and The upper height of the damper receiving groove is formed higher than the center height of the bearing damper. Satisfying at least one of the following conditions, Motor for vehicles.

7. Shaft; A rotor fixed to the above shaft; A stator arranged around the rotor; A second bearing that rotatably supports the shaft; A bearing support supporting the second bearing; and A vehicle motor including a bearing damper made of rubber, which is interposed between the bearing and the bearing support in an axially facing contact portion.

8. In paragraph 7, A motor for a vehicle, wherein the bearing and the bearing support are interposed in a radially facing contact portion, and includes an O-ring for absorbing vibration and sealing to the outside.

9. In paragraph 7, A motor housing including the shaft, the rotor, and the stator therein, A motor for a vehicle, wherein the bearing support is located at the center of the bottom of the motor housing.

10. A vehicle having a motor for a vehicle as defined in any one of paragraphs 1 to 9.

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