Patent Description:
In recent years, due to the energy-saving trend of electrical equipment, the motors used are usually high-efficiency brushless DC motors instead of induction motors. For example, air-conditioning units use high-efficiency brushless DC motors to drive fans. These brushless DC motors are driven by inverters, which use pulse width modulation (hereinafter referred to as PWM) as the driving method. In the use of this PWM driving method, the neutral point potential of the winding is not zero and a common mode voltage is generated. In the case of high frequency, a coupling capacitance will be generated between the motor structures, and the common mode voltage will form a loop through the coupling capacitance between the stator, the rotor, the permanent magnet, the end cover, and other parts and the bearing capacitance, thereby generating voltage on the bearing capacitance branch. The voltage generated between the inner and outer rings of the bearing (bearing capacitance branch) due to the common mode voltage is called the shaft voltage. The shaft voltage contains the high-frequency components of the high-speed switching action during the semiconductor during PWM driving. If the shaft voltage reaches the insulation breakdown voltage of the lubricating oil film inside the bearing, it will discharge and generate current, which will cause partial melting corrosion phenomenon of the inner surface of the bearing and the balls, this is what we call bearing electrical corrosion. When the electric corrosion progresses gradually, wave-shaped wear will occur on the bearing, which will eventually cause abnormal noise and decrease the life of the bearing.

In order to prevent electrical corrosion of bearings, many solutions have been proposed in the industry, which can be roughly summarized into the following three types: (<NUM>) Making the inner and outer rings of the bearing in a conductive state, (<NUM>) Making the inner and outer rings of the bearing in a reliable insulated state, (<NUM>) Reduce the shaft voltage. For the method (<NUM>), it has been proposed to use conductive bearing grease, but it is actually difficult to apply because it cannot achieve the same service life as non-conductive grease and high cost. In addition, there is also a way to install a conductive brush on the shaft, which will cause problems such as wear of the brush, need for installation space, high implementation cost, and need for maintenance. For the method (<NUM>), there are cases where ceramic ball bearings are used in actual product applications, which have good results. However, ceramic ball bearings are very expensive and difficult to apply on a large scale, especially in some applications with high cost requirements. For the method (<NUM>), a variety of invention technologies for reducing the shaft voltage are proposed. Among them, an invention patent <CIT> proposes that an insulation layer is provided between the inner and outer sides of the rotor of the motor to increase the impedance of the rotor and greatly reduce the shaft voltage, which can decrease from tens of volts to less than ten volts, and as the thickness of the insulation layer increases, the shaft voltage gradually decreases. In practice, we can also see the application of this technology in some motor products. However, in some large-power plastic-packaged DC motors, the shaft voltage is not improved instead the shaft voltage will increase, resulting in an increase in the risk of electrical corrosion of the bearing.

<CIT> relates generally to a tapping device comprising a brush holder, which is made of electrically conductive material and can be connected to a base body of an electric machine. The tapping device further comprises a brush, which is made of electrically conductive material. <CIT> relates generally to a molded motor comprising a stator with a stator winding wound onto a stator iron core; a shaft passing through the center of the motor; a rotor integrally formed with the shaft and freely rotated at the inner peripheral side of the stator; a bearing used for supporting the shaft; and a bracket finished product used for fixing the bearing. <CIT> relates generally to a motor including a stator forming a coil by being wound around an iron core constructed of a plurality of teeth; a rotor in which magnets arranged in an outer periphery of a shaft are integrated by resin parts and a rolling bearing are provided at both ends in an axial direction of the shaft, respectively; and a bracket which supports one rolling bearing of the rotor.

One of the objects of embodiments of the present application is to provide a motor and an electrical equipment, in order to solve the technical problem of electrical corrosion of the large-power bearing.

In order to solve the technical problem above mentioned, according to the invention a motor is provided, which includes:.

In an embodiment of the invention, an electrical equipment is provided, which includes the motor above mentioned.

The beneficial effects of the motor and the electrical equipment provided by the embodiments of the present invention are as follows:
The traditional integrated bearing bracket is separated into the stator bracket portion and the bearing support portion, and the bracket insulation layer is provided between the stator bracket portion and the bearing support portion, which is equivalent to adding an insulation layer capacitance C1 between the stator bracket portion and the bearing support portion. The capacitance Cd between the bearing outer ring and the stator core is decomposed into the equivalent capacitance Cd2 after the capacitance C1 between the bearing support portion and the stator bracket portion and the capacitance C2 between the stator bracket portion and the stator core are connected in series, and then in parallel with the capacitance Cd1 between the bearing support portion and the stator core.

The arrangement of the bracket insulation layer can make the capacitance C1 much smaller than C2 and Cd2 smaller than C1 on the one hand; on the other hand, the bearing support portion of the bearing bracket can have no or reduce the area directly facing the stator core in the axial direction of the motor, and be far away from the stator core, that is, the value of the capacitance Cd1 can also be small. Therefore, the equivalent capacitance Cd of the stator side can be greatly reduced.

In the loop of the high-frequency circuit, there is also a capacitance Cb between the bearing outer ring and the bearing inner ring. The shaft voltage is the divided voltage between the two ends of the capacitance Cb. The capacitance Cd is equivalent to being connected in series on the outer ring side of the bearing of the capacitance Cb. Therefore, the capacitance Cd is reduced through the arrangement of the bracket insulation layer, so that the two ends of the capacitance Cb obtain a smaller divided voltage, that is, the shaft voltage is reduced, and the risk of electric corrosion of the bearing is effectively reduced. For motors with larger power and larger metal shells to increase the installation strength and ensure heat dissipation, the risk of electrical corrosion damage to the motor bearings can also be reduced.

The electrode structure is used to adjust the equivalent capacitance Cb between the bearing inner ring and the bearing outer ring, the electrode structure is electrically connected to the bearing bracket and forms an adjustment capacitance C3 with the rotor shaft; or the electrode structure is electrically connected to the rotor shaft and forms an adjustment capacitance C3 with the bearing bracket.

The adjustment capacitance C3 is connected in parallel with the bearing capacitances Cb1 and Cb2 to increase the equivalent capacitance Cb and reduce the voltage difference between the two ends of the equivalent capacitance Cb. On the one hand, the parallel connection of the adjustment capacitance C3 will increase the equivalent capacitance Cb, and make the equivalent capacitance Cb to obtain a smaller divided voltage, that is, the voltage difference between the bearing inner ring and the bearing outer ring is reduced, and the shaft voltage is reduced; on the other hand, when the adjustment capacitance C3 is relatively large relative to the bearing capacitances Cb1 and Cb2, the current between the bearing bracket and the rotor shaft will pass through the branch of the adjustment capacitance C3 to shunt the shaft current, thereby reducing the current flowing through the bearing outer ring and bearing inner ring, that is the shaft current. Therefore, the risk of electrical corrosion damage to the bearing can be greatly reduced.

The motor and the electrical equipment having the motor can effectively reduce the motor shaft voltage, thereby reducing the risk of electrical corrosion damage to the motor bearing and improving the reliability of the motor.

In order to explain the embodiments of the present application, i.e. present invention, more clearly, a brief introduction regarding the accompanying drawings that need to be used for describing the embodiments of the present application or the prior art is given below.

In order to make the purpose, the technical solution and the advantages of the present application, i.e. invention, be clearer and more understandable, the present application will be further described in detail below with reference to accompanying figures and embodiments. It should be understood that the specific embodiments described herein are merely intended to illustrate but not to limit the present invention. All the embodiments referred to as embodiments of the present application mentioned in the detailed description are in the scope of present invention.

In the description of the present application, it needs to be understood that, directions or location relationships indicated by terms such as "length", "width", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", and so on are the directions or location relationships shown in the accompanying figures, which are only intended to describe the present application conveniently and simplify the description, but not to indicate or imply that an indicated device or component must have specific locations or be constructed and manipulated according to specific locations; therefore, these terms shouldn't be considered as any limitation to the present application.

In addition, terms "the first" and "the second" are only used in describe purposes, and should not be considered as indicating or implying any relative importance, or impliedly indicating the number of indicated technical features. As such, technical feature(s) restricted by "the first" or "the second" can explicitly or impliedly comprise one or more such technical feature(s). In the description of the present application, "a plurality of" means two or more, unless there is additional explicit and specific limitation.

In the present application, unless there is additional explicit stipulation and limitation, terms such as "mount", "connect with each other", "connect", "fix", and so on should be generally interpreted, for example, "connect" can be interpreted as being fixedly connected, detachably connected, or connected integrally; "connect" can also be interpreted as being mechanically connected or electrically connected; "connect" can be further interpreted as being directly connected or indirectly connected through intermediary, or being internal communication between two components or an interaction relationship between the two components. For the one of ordinary skill in the art, the specific meanings of the aforementioned terms in the present application can be interpreted according to specific conditions.

Referring to <FIG>, an exemplary plastic-packaged DC motor with larger power has a large motor power, a large torque, and a high temperature rise. In order to ensure the installation strength of the motor and the electrical equipment using the motor, and to ensure the heat dissipation of the motor, it is generally used at least one larger metal shell as the bearing bracket <NUM>' on one side of the motor. The bearing bracket <NUM>' is connected to and supports the plastic-packaged stator <NUM>' of the motor, and is fixedly connected to the mounting bracket of the electrical equipment, and is also connected to and supports a bearing outer ring <NUM>' on one side of the bearing <NUM>' of the motor. For the motor with the above solution, if an insulation layer is provided between the inner and outer sides of the rotor corresponding to the patent <CIT>, the shaft voltage will not be improved instead the shaft voltage will increase, and resulting in the risk of electrical corrosion of the bearing increasing. The applicant discovered the specific reasons as follows:
This kind of motor uses an insulated rotor <NUM>', which is rotatably mounted on the stator <NUM>'. Since a rotor insulation layer <NUM>' is provided between the inner core <NUM>' and the outer core <NUM>' of the rotor, which is equivalent to adding a Cz3 between the inner core <NUM>' of the rotor and the outer core <NUM>' of the rotor, and for the rotor-side capacitive coupling loop from the bearing inner ring <NUM>' to the stator core <NUM>', the magnet capacitance Cz2 and the air gap capacitance Cz1 between the stator <NUM>' and the rotor <NUM>' are further provided, the capacitances Cz1, Cz2, and Cz3 are connected in series, and the equivalent capacitance is arranged to be Cz. In general, the capacitance of the rotor insulation layer capacitance Cz3 is small, generally tens of PF, so the equivalent capacitance Cz is also small.

Compared with the equivalent capacitance Cd between the bearing outer ring <NUM>' and the stator core <NUM>', the bearing bracket <NUM>' electrically connected to the bearing outer ring <NUM>' of the above-mentioned motor has a larger area and is provided with a portion directly close to the stator core <NUM>' in the axial or radial direction, or due to the metal bracket in the electrical equipment electrically connected to the bearing bracket <NUM>' is provided with a portion close to the stator core <NUM>', such that the capacitance Cd between the bearing outer ring <NUM>' electrically connected to the bearing bracket <NUM>' and the stator core <NUM>' is relatively large, generally several hundred PF or more.

Since ends of the capacitance Cd on the stator side and the capacitance Cz on the rotor side are connected to the stator core <NUM>', and the other ends are connected to the bearing outer ring <NUM>' and the bearing inner ring <NUM>', the capacitance difference between Cd and Cz will cause the voltage difference between the bearing outer ring <NUM>' and the bearing inner ring <NUM>' larger, that is, the shaft voltage is too large, thereby increasing the risk of electric corrosion of the bearing <NUM>'.

Referring to <FIG>, <FIG>, and <FIG>, the present invention provides a motor, which includes a stator <NUM>, a rotor <NUM>, a bearing <NUM>, a bearing bracket <NUM>, and an electrode structure <NUM>. The stator <NUM> includes a stator core <NUM> having windings <NUM>. The rotor <NUM> is rotatably mounted on the stator <NUM>. The rotor <NUM> includes a rotor core <NUM> and a rotor shaft <NUM> located at the center of the rotor core <NUM> and connected to the rotor core <NUM>. The rotor core <NUM> may include a permanent magnet <NUM>. The rotor core <NUM> rotates synchronously with the rotor shaft <NUM>.

The bearing <NUM> is configured to support the rotor shaft <NUM> so that the rotor shaft <NUM> can rotate freely. The bearing <NUM> includes a bearing inner ring <NUM> and a bearing outer ring <NUM>. The bearing inner ring <NUM> is sleeved on the outer peripheral surface of the rotor shaft <NUM> and is confined on the rotor shaft <NUM> along the axial direction of the rotor shaft <NUM>, and the bearing inner ring <NUM> is in conduction with the rotor shaft <NUM>. The bearing outer ring <NUM> is mounted on the bearing bracket <NUM> and is confined on the bearing bracket <NUM> in the radial and axial directions. Rollers <NUM> are provided between the bearing outer ring <NUM> and the bearing inner ring <NUM> so that the bearing outer ring <NUM> and the bearing inner ring <NUM> can rotate freely.

Referring to <FIG> together, the bearing bracket <NUM> includes a bearing support portion <NUM> made of conductive material and configured for fixing and conducting the bearing outer ring <NUM>; at least one bearing bracket <NUM> also includes a stator bracket portion <NUM> made of conductive material and configured for connection to the stator <NUM>, the stator bracket portion <NUM> is located on the radially outer side of the bearing support portion <NUM>. A bracket insulation layer <NUM> is provided between the bearing support portion <NUM> and the stator bracket portion <NUM> so that the stator bracket portion <NUM> and the bearing support portion <NUM> insulation.

The traditional integrated bearing bracket is separated into the stator bracket portion <NUM> and the bearing support portion <NUM>, and the bracket insulation layer <NUM> is provided between the stator bracket portion <NUM> and the bearing support portion <NUM>, which is equivalent to adding an insulation layer capacitance C1 between the stator bracket portion <NUM> and the bearing support portion <NUM>. The capacitance Cd between the bearing outer ring <NUM> and the stator core <NUM> is decomposed into the equivalent capacitance Cd2 after the capacitance C1 between the bearing support portion <NUM> and the stator bracket portion <NUM> and the capacitance C2 between the stator bracket portion <NUM> and the stator core <NUM> are connected in series, and then in parallel with the capacitance Cd1 between the bearing support portion <NUM> and the stator core <NUM>.

The arrangement of the bracket insulation layer <NUM> can make the capacitance C1 much smaller than C2 and Cd2 smaller than C1 on the one hand; on the other hand, the bearing support portion <NUM> of the bearing bracket <NUM> can have no or reduce the area directly facing the stator core <NUM> in the axial direction of the motor, and be far away from the stator core <NUM>, that is, the value of the capacitance Cd1 can also be small. Therefore, the equivalent capacitance Cd of the stator side can be greatly reduced.

In the loop of the high-frequency circuit, there is also a capacitance Cb between the bearing outer ring <NUM> and the bearing inner ring <NUM>. The shaft voltage is the divided voltage between the two ends of the capacitance Cb. The capacitance Cd is equivalent to being connected in series on the outer ring side of the bearing of the capacitance Cb. Therefore, the capacitance Cd is reduced through the arrangement of the bracket insulation layer <NUM>, such that it is balanced with the smaller capacitance Cz connected in series on the inner ring side of the bearing, so that the two ends of the capacitance Cb obtain a smaller divided voltage, that is, the shaft voltage is reduced, and the risk of electric corrosion of the bearing is effectively reduced. For motors with larger power and larger metal shells to increase the installation strength and ensure heat dissipation, the risk of electrical corrosion damage to the motor bearings <NUM> can also be reduced.

The motor further includes an electrode structure <NUM> used to adjust the equivalent capacitance Cb between the bearing inner ring <NUM> and the bearing outer ring <NUM>, which includes two solutions. Referring to <FIG> and <FIG>, a first solution is that the electrode structure <NUM> is electrically connected to the bearing bracket <NUM>, which is equivalent to adding a conductive electrode plate at a position close to the rotor shaft <NUM>, and an adjustment capacitance C3 is formed between the electrode plate and the rotor shaft <NUM>, and the electrode structure (i.e. the electrode plate) is electrically connected to the bearing bracket <NUM>, which can be regarded that the bearing inner ring <NUM> is extended by the rotor shaft <NUM>, and the bearing outer ring <NUM> is extended by the electrode structure <NUM>, the two extended portions are respectively provided with an area facing each other and are non-conducting, hereby forming the adjustment capacitance C3, which is equivalent to the above adjustment capacitance C3 being connected in parallel between the bearing outer ring <NUM> and the bearing inner ring <NUM>.

Referring to <FIG>, the second solution is that the electrode structure <NUM> is electrically connected to the rotor shaft <NUM>, which is equivalent to adding a conductive electrode plate that has an equal potential with the rotor shaft <NUM> on the rotor shaft <NUM>. The bearing bracket <NUM> and the electrode structure <NUM> are spaced apart, and the bearing bracket <NUM> is electrically connected to the bearing outer ring <NUM>, which is equivalent to adding an electrode plate that has an equal potential with the bearing outer ring <NUM> on the bearing outer ring <NUM>. An adjustment capacitance C3 is formed between the two electrode plates and the rotor shaft <NUM> is electrically connected to the bearing inner ring <NUM>. Therefore, the adjustment capacitance C3 is equivalent to being connected in parallel between the bearing outer ring <NUM> and the bearing inner ring <NUM>.

Among them, the electrical connection includes direct and indirect electrically conductive connection, and connection through a large capacitance. The connection through a large capacitance, such as a thin insulation layer is provided between two metal members. As long as the distance between the two metal parts is close enough and the facing area is large enough, the capacitance value between the two metal parts will be large enough.

For the above two solutions, if both ends of the rotor core <NUM> are respectively provided with one bearing <NUM>, two bearings <NUM> are provided, and the high-frequency equivalent circuit between the bearing outer ring <NUM> and the bearing inner ring <NUM> of one bearing <NUM> can also be equivalent to a coupling capacitance Cb1. The high-frequency equivalent circuit between the bearing outer ring <NUM> and the bearing inner ring <NUM> of another bearing <NUM> can also be equivalent to a coupling capacitance Cb2. The shaft voltage is the divided voltage on Cb1 and Cb2.

Each bearing <NUM> is installed on a bearing bracket <NUM> respectively, and the bearing inner rings <NUM> of the two bearings are electrically connected to the rotor shaft <NUM>. In order to simplify the analysis, the description is made based on the electrical connection of the two bearing brackets <NUM>, and the above-mentioned capacitances Cb1 and Cb2 are equivalent to being connected in parallel. The arrangement of the above electrode structure <NUM> is equivalent to connecting the adjustment capacitance C3 in parallel with the bearing capacitances Cb1 and Cb2. The total capacitance of Cb1, Cb2, and C3 in parallel is the above-mentioned "equivalent capacitance". It can be understood that when the two bearing brackets <NUM> (or bearing outer ring <NUM>) are not electrically connected, Cb1 or Cb2 and C3 are connected in parallel, and the total capacitance of the two in parallel is the above-mentioned "equivalent capacitance". The above-mentioned Cb1 and Cb2 are respectively the bearing capacitances of the corresponding bearings, which is related to the facing areas of the bearing inner ring and the bearing outer ring. For a given bearing, the bearing capacitance is also determined. The equivalent capacitance is denoted as Cb, by adjusting the facing area between the electrode structure <NUM> and the rotor shaft <NUM> (the first solution) or the electrode structure <NUM> and the bearing bracket <NUM> (the second solution) and the size of the air gap between the electrode structure <NUM> and the rotor shaft <NUM>, or the electrode structure <NUM> and the bearing bracket <NUM>, which can effectively change the amount of the adjustment capacitance C3 and the amount of the equivalent capacitance Cb. For the convenience of description, assuming that the capacitance formed by the bearing outer ring <NUM> through the bearing bracket <NUM> and the stator core <NUM> is Cd, and the equivalent capacitance formed between the bearing inner ring <NUM> and the stator core <NUM> through the air gaps of the rotor shaft <NUM>, the permanent magnet <NUM>, the stator <NUM>, and the rotor <NUM> is Cz. The coupling capacitance loop formed by the entire motor includes the above-mentioned equivalent capacitances Cb, Cd, and Cz.

The adjustment capacitance C3 is connected in parallel with the bearing capacitances Cb1 and Cb2 to increase the equivalent capacitance Cb and reduce the voltage difference between the two ends of the equivalent capacitance Cb. On the one hand, the parallel connection of the adjustment capacitance C3 will increase the equivalent capacitance Cb, such that the equivalent capacitance Cb obtain a smaller divided voltage, that is, the voltage difference between the bearing inner ring <NUM> and the bearing outer ring <NUM> is reduced, and the decreased shaft voltage is realized. On the other hand, when the adjustment capacitance C3 is relatively large relative to the bearing capacitances Cb1 and Cb2, the current between the bearing bracket <NUM> and the rotor shaft <NUM> will pass through the branch of the adjustment capacitance C3 to shunt the shaft current, thereby reducing the current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>, that is, the shaft current, and therefore, the risk of electrical corrosion damage to the bearing <NUM> can be greatly reduced.

The motor and the electrical equipment having the motor can effectively reduce the motor shaft voltage, thereby reducing the risk of electrical corrosion damage to the motor bearing <NUM> and improving the reliability of the motor.

Referring to <FIG>, according to the invention, the bearings <NUM> are provided with two, and two bearings <NUM> are arranged on both sides of the rotor core <NUM> at intervals along the axial direction of the rotor core <NUM>, and each bearing <NUM> is provided with a bearing bracket <NUM>. The two sets of bearings <NUM> are arranged at intervals, and are located at positions sandwiching the rotor core <NUM> in the axial direction, and support the rotor shaft <NUM> to freely rotate. The two sets of bearings <NUM> are respectively mounted on two bearing brackets <NUM>. The bearing bracket <NUM> on the shaft extension side X and the outside of the stator core <NUM> are plastic-packaged and molded into a plastic shell <NUM>, and the bearing bracket <NUM> on the non-shaft extension side X' is mounted on the plastic shell <NUM>. The motors shown in <FIG> and <FIG> are two other embodiments in which two bearings <NUM> and two bearing brackets <NUM> are arranged.

Referring to <FIG> and <FIG> to <FIG>. According to the invention, the bearing support portions <NUM> of the two bearing brackets <NUM> are electrically connected by a conductive member <NUM>, and the conductive member <NUM> is insulated from the stator bracket portion <NUM>, which is equivalent to electrically connecting the two bearing outer rings <NUM>, and the two bearing inner rings <NUM> are electrically connected through the rotor shaft <NUM>. Therefore, the above adjustment effect will affect the shaft voltages of the two bearings <NUM> at the same time, thereby the effect of the risk of electric corrosion of the two bearings <NUM> are reduced at the same time.

In this embodiment, referring to <FIG> and <FIG>, the conductive member <NUM> includes two terminals <NUM> arranged at intervals and a power cord <NUM> connected between the two terminals <NUM> and an outer surface of the power cord <NUM> is an insulation portion. The two terminals <NUM> can be respectively connected to the bearing support portions <NUM> of the two bearing brackets <NUM>, so that the two bearing brackets <NUM> are conducted, and the power cord <NUM> has a compact structure and is easy to be assembled. Referring to <FIG> at the same time, specifically, the two bearing brackets <NUM> are respectively located on the shaft extension side X and the non-shaft extension side X'. A part of the power cord <NUM> is arranged on the outer circumferential surface of the plastic shell <NUM> along the axial direction of the stator <NUM>, and the other part of the power cord <NUM> is arranged on one end surface of the plastic shell <NUM> along the radial direction of the stator <NUM>. The bearing bracket <NUM> on the shaft extension side X covers the other end surface of the stator core <NUM>. The overall structure occupies a small space.

In the embodiment, referring to <FIG>, the bearing support portion <NUM> of each bearing bracket <NUM> is provided with a connecting hole <NUM>, and the two terminals <NUM> are electrically connected to the two connecting holes <NUM> in a one-to-one correspondence. The terminals <NUM> of the power cord <NUM> abuts against the connection holes <NUM>, and the terminals <NUM> are fixed to the bearing support <NUM> by fasteners <NUM>. This solution is easy to be assembled and has a compact structure, the two bearing brackets <NUM> are conducted, and then the two bearing outer rings <NUM> are conducted.

Referring to <FIG> and <FIG>, in another embodiment of the present application, one of the bearing brackets <NUM> and the stator core <NUM> are integrally molded with a plastic shell <NUM>, so that the bearing bracket <NUM> is insulated from the stator core <NUM>. Specifically, the plastic shell <NUM> may be formed by molding with a resin material. The outer surface of the plastic shell <NUM> of the stator <NUM> is provided with a mounting groove <NUM> for mounting the power cord <NUM>. During assembly, the power cord <NUM> is mounted in the mounting groove <NUM> to facilitate the assembly of the power cord <NUM>.

Referring to <FIG> and <FIG>. In another embodiment of the present application, the stator bracket portion <NUM> is a metal member for forming a capacitance. Specifically, the stator bracket portion <NUM> can be made of aluminum or other metal materials, which is easy to be stamped and stretched.

Referring to <FIG>, in another embodiment of the present application, for the bearing bracket <NUM> with the bracket insulation layer <NUM>, the bracket insulation layer <NUM> is injection molded through the region between the stator bracket portion <NUM> and the bearing support portion <NUM>. The bracket insulation layer <NUM> is injection-molded between the stator bracket portion <NUM> and the bearing support portion <NUM> such that the bearing bracket <NUM> as a whole and to insulate the stator bracket portion <NUM> and the bearing support portion <NUM> from each other. The bracket insulation layer <NUM> can be made of thermosetting material, which has good insulation properties. Specifically, the material of the insulation layer is Bulk Molding Compound (BMC) or polybutylene terephthalate (PBT) or other insulation materials, which is arranged as required.

Referring to <FIG> and <FIG>, in another embodiment of the present application, the stator bracket portion <NUM> is provided with a plurality of first arm portions <NUM> extending radially inwardly of the bearing bracket <NUM>; the bearing support portion <NUM> is provided with a plurality of second arm portions <NUM> extending radially outwardly of the bearing bracket <NUM>; the first arm portions <NUM> and the second arm portions <NUM> are embedded in the bracket insulation layer <NUM>. The first arm portion <NUM> and the second arm portion <NUM> are provided to extend the first arm portions <NUM> and the second arm portions <NUM> into the bracket insulation layer <NUM> when the bracket insulation layer <NUM> is injection molded, so that the bracket insulation layer <NUM> is more firmly combined with the stator bracket portion <NUM> and the bearing support portion <NUM>, and at the same time, the first arm portions <NUM> and the second arm portions <NUM> can improve the structural strength of the region of the bracket insulation layer <NUM>.

In the embodiment, the first arm portions <NUM> and the second arm portions <NUM> are arranged in pairs, and are at least partially opposite to each other in the radial direction of the motor. This solution can better enable the bracket insulation layer <NUM> to be more firmly combined with the stator bracket portion <NUM> and the bearing support portion <NUM>, and at the same time can improve the structural strength of the region of the bracket insulation layer <NUM>.

Referring to <FIG> and <FIG>, in another embodiment of the present application, the stator bracket portion <NUM> is provided with a plurality of first through holes <NUM> extending in the axial direction of the bearing bracket <NUM>, and the first through holes <NUM> are at least partially buried in the bracket insulation layer <NUM>; the bearing support portion <NUM> is provided with a plurality of second through holes extending along the axial direction of the bearing bracket <NUM>, and the second through holes are at least partially buried in the bracket insulation layer <NUM>. The first through holes <NUM> and the second through holes are provided for the purpose of injecting the insulating material into the first through hole <NUM> and the second through hole when the bracket insulation layer <NUM> is injection molded, thereby increasing the contact area of the bracket insulation layer <NUM> and the stator bracket portion <NUM>, and the bearing support portion <NUM> allows the bracket insulation layer <NUM> to be more firmly combined with the stator bracket portion <NUM> and the bearing support portion <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, in another embodiment of the present application, the stator bracket portion <NUM> is provided with a first fixing portion <NUM>, and the first fixing portion <NUM> is connected to the plastic shell <NUM> to realize the bearing bracket <NUM> having the stator bracket portion <NUM> being assembled on the plastic shell <NUM>. In the embodiment, the bearing bracket <NUM> can be connected to the plastic shell <NUM> by screws <NUM>, which is easy to be assembled.

In another embodiment of the present application, the stator bracket portion <NUM> is provided with a second fixing portion <NUM>, and the second fixing portion <NUM> is connected to the bracket <NUM> of the electrical equipment using the motor to realize the fixing of the motor. The bracket <NUM> is made of metal, and the second fixing portion <NUM> is electrically connected to the bracket <NUM>. Specifically, the second fixing portion <NUM> and the bracket <NUM> are electrically connected by a power cord. The bracket <NUM> is electrically connected with the power ground of the electrical equipment or with the earth. The bracket insulation layer <NUM> is provided to reduce the stator side capacitance Cd, so that the two ends of the bearing capacitance Cb connected in series with the Cd obtain a smaller divided voltage, that is, the shaft voltage is reduced; and the effect of the bracket <NUM> of the electrical equipment connected to the stator bracket portion <NUM> on the shaft voltage is weakened.

Referring to <FIG>, in another embodiment of the present application, the rotor <NUM> of the motor uses an insulated rotor <NUM> structure, that is, a rotor insulation layer <NUM> is provided between the rotor shaft <NUM> and the outer peripheral surface of the rotor core <NUM>. For example, the rotor insulation layer <NUM> is provided between the outer core <NUM> of the rotor <NUM> and the inner core <NUM> of the rotor <NUM>. As before, this solution can make the equivalent capacitance Cz of the rotor side connected to the bearing inner ring <NUM> smaller. In this case, by providing the bracket insulation layer <NUM> between the stator bracket portion <NUM> and the bearing support portion <NUM> of the bearing bracket <NUM>, the value of the capacitance Cd can be reduced. By adjusting the facing areas and distance between the bearing support portion <NUM> and the stator bracket portion <NUM>, and by means of adjusting the dielectric constant of the material of the bracket insulation layer <NUM> can change the value of the capacitance C1, thereby changing the value of the capacitance Cd. Specifically, the rotor insulation layer <NUM> may be made of PBT or rubber. The motors shown in <FIG> and <FIG> are two other similar embodiments.

In the embodiment, when the equivalent capacitance Cd between the bearing outer ring <NUM> and the stator core <NUM> is reduced to match (approximately) the equivalent capacitance Cz between the bearing inner ring <NUM> and the stator core <NUM>, the potentials of the bearing outer ring <NUM> and the bearing inner ring <NUM> are close, which can greatly reduce the voltage difference between the bearing outer ring <NUM> and the bearing inner ring <NUM>, that is, reduce the shaft voltage, thereby effectively reducing the risk of electric corrosion of the bearing <NUM>.

Referring to <FIG> and <FIG>, in another embodiment of the present application, the electrode structure includes a sleeve portion <NUM> disposed on the bearing support portion <NUM> of at least one bearing bracket <NUM>, the sleeve portion <NUM> and the bearing support portion <NUM> are electrically connected to each other, and a first air gap <NUM> extending along the radial direction of the rotor shaft <NUM> is formed between the sleeve portion <NUM> and the rotor shaft <NUM>. With reference to the previous analysis of the first solution, it is equivalent to adding an adjustment capacitance C3 between the rotor shaft <NUM> and the bearing support portion <NUM>. The coupling capacitance loop formed by the entire motor includes the above-mentioned equivalent capacitances Cb, Cd, and Cz. Therefore, the arrangement of the sleeve portion <NUM>, on the one hand, can increase the equivalent capacitance Cb, so that both ends (that is, the bearing outer ring <NUM> and the bearing inner ring <NUM>) of the equivalent capacitance Cb are in the circuit formed by the stator side capacitance Cd connected in series with the equivalent capacitance Cb, a smaller divided voltage divider is obtained, that is, a smaller shaft voltage; on the other hand, the current between the bearing bracket <NUM> and the rotor shaft <NUM> will pass through the branch of the above-mentioned adjustment capacitance C3 to shunt the shaft current, thereby reducing the current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>, that is the shaft current. Therefore, the risk of electrical corrosion damage to the bearing <NUM> can be greatly reduced.

In another embodiment of the present application, one end of the rotor shaft <NUM> in the axial direction is provided with a shaft hole <NUM> extending along the axial direction, and the sleeve portion <NUM> includes an outer sleeve <NUM> located outside the outer peripheral surface of the rotor shaft <NUM> and an inner sleeve <NUM> extending in the shaft hole <NUM>, and the inner sleeve <NUM> is located inside the outer sleeve <NUM>. By arranging the outer sleeve <NUM> sleeved on the rotor shaft <NUM> and an inner sleeve <NUM> extending into the rotor shaft <NUM>, the facing area of the sleeve portion <NUM> to the rotor shaft <NUM> can be increased to increase the adjustment capacitance C3. The adjustment capacitance C3 is formed between the sleeve portion <NUM> and the rotor shaft <NUM>, and the adjustment capacitance C3 is connected in parallel with the bearing capacitances Cb1 and Cb2. On the one hand, the shaft voltage between the bearing outer ring <NUM> and the bearing inner ring <NUM> can be reduced; on the other hand, the shaft current can be shunted. The current between the bearing bracket <NUM> and the rotor shaft <NUM> is shunted from the branch of the above-mentioned adjustment capacitance C3, which effectively reduce the shaft current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>. Specifically, a closing plate <NUM> is connected to the same end surface of the outer sleeve <NUM> and the inner sleeve <NUM>. The closing plate <NUM> can prevent foreign matter from entering the shaft hole <NUM> and the inside of the motor, so as to ensure the reliable operation of the shaft sleeve portion <NUM>.

In another embodiment of the present application, the cross-sectional shape of the first air gap <NUM> in the radial direction is in a circular ring shape concentric with the rotor shaft <NUM>. The adjustment capacitance C3 of a predetermined value is formed between the rotor shaft <NUM> and the sleeve portion <NUM>, and the adjustment capacitance C3 is connected in parallel with the bearing capacitances Cb1 and Cb2.

In another embodiment of the present application, the distance in the radial direction of the first air gap <NUM> is less than or equal to <NUM>, such that the value of the adjustment capacitance C3 is relatively large, so as to increase the equivalent capacitance Cb, so that the divided voltage obtained at two ends of the equivalent capacitance Cb are smaller, hat is, the voltage difference between the bearing inner ring <NUM> and the bearing outer ring <NUM> is reduced, and the shaft voltage is reduced. At the same time, the adjustment capacitance C3 is arranged to be larger than the bearing capacitances Cb1 and Cb2, so that the electricity at both ends of the equivalent capacitance Cb can be more concentrated on both ends of the adjustment capacitance C3, which is equivalent to concentrated on the sleeve portion <NUM> and the rotor shaft <NUM> close to the sleeve portion <NUM> to reduce the shaft current.

In another embodiment of the present application, the sleeve portion <NUM> and the bearing support portion <NUM> are metal members integrally formed, and the integral forming process, such as stamping and stretching, is adopted for easy processing. Specifically, the sleeve portion <NUM> and the bearing support portion <NUM> may be aluminum members or other metal members, which can realize electric conduction and are easy to be press-formed.

Referring to <FIG> and <FIG>. In another embodiment of the present application, the electrode structure <NUM> is disposed on the rotor shaft <NUM>, which is easy to be assembled. The adjustment capacitance C3 is formed between the electrode structure <NUM> and the bearing bracket <NUM>, and the rotor shaft <NUM> is electrically connected to the bearing inner ring <NUM>. Therefore, the adjustment capacitance C3 is equivalent to being connected in parallel between the bearing outer ring <NUM> and the bearing inner ring <NUM>. With reference to the previous analysis of the second solution, the coupling capacitance loop formed by the entire motor includes the above-mentioned equivalent capacitances Cb, Cd, and Cz. The adjustment capacitance C3 is connected in parallel with the bearing capacitances Cb1 and Cb2 to increase the equivalent capacitance Cb and reduce the voltage difference between the two ends of the equivalent capacitance Cb. On the one hand, the parallel connection of the adjustment capacitance C3 will increase the equivalent capacitance Cb, such that the equivalent capacitance Cb obtains a smaller divided voltage in the equivalent loop of the equivalent capacitance Cd in series with the bearing outer ring <NUM> and the equivalent capacitance Cz in series with the bearing inner ring <NUM>, that is the voltage difference between the bearing inner ring <NUM> and the bearing outer ring <NUM> is reduced to reduce the shaft voltage; on the other hand, the current between the bearing bracket <NUM> and the rotor shaft <NUM> will flow through the branch of the above-mentioned adjusting capacitor C3 to shunt the shaft current, thereby reducing the current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>, that is, the shaft current. Therefore, the risk of electrical corrosion damage to the bearing <NUM> can be greatly reduced.

Referring to <FIG>, in another embodiment of the present application, the electrode structure <NUM> includes a plurality of first conductive cylinders <NUM> that are sequentially sleeved and arranged at intervals. The first conductive cylinders <NUM> are arranged around the rotor shaft <NUM> and are extended along the axis direction, the first conductive cylinders <NUM> are electrically connected to the rotor shaft <NUM>, which is equivalent to adding a conductive electrode plate with the same potential as the rotor shaft <NUM> on the rotor shaft <NUM>. A plurality of second conductive cylinders <NUM> are provided on the bearing support portion <NUM> of the bearing bracket <NUM> close to the electrode structure <NUM>. The second conductive cylinders <NUM> are arranged around the rotor shaft <NUM> and are extended along the axial direction. The second conductive cylinders <NUM> are electrically connected to the bearing support portion <NUM>; which is equivalent to adding an electrode plate with the same potential as the bearing outer ring <NUM> on the bearing outer ring <NUM>. The first conductive cylinders <NUM> and the second conductive cylinders <NUM> are arranged opposite to each other in the radial direction of the motor, and the second air gap <NUM> extending along the axial direction of the rotor shaft <NUM> is formed between the first conductive cylinder <NUM> and the second conductive cylinder <NUM>. An adjustment capacitance C3 is formed between the two electrode plates, and the rotor shaft <NUM> is electrically connected to the bearing inner ring <NUM>. Therefore, the adjustment capacitance C3 is equivalent to being connected in parallel between the bearing outer ring <NUM> and the bearing inner ring <NUM>. On the one hand, the shaft voltage between the bearing outer ring <NUM> and the bearing inner ring <NUM> can be reduced; on the other hand, the shaft current can be shunted, such that the current between the bearing bracket <NUM> and the rotor shaft <NUM> is shunted from the branch circuit of the adjustment capacitor C3, which effectively reduces the shaft voltage and shaft current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>. The solution of the first conductive cylinders <NUM> and the second conductive cylinders <NUM> facilitates the internal heat of the motor to pass through the air gap between the rotor shaft <NUM> and the innermost second conductive cylinder <NUM> and the air gap between the first conductive cylinder <NUM> and the second conductive cylinder <NUM> to be transmitted to the outside, which is conducive to the heat dissipation of the motor. In addition, the distance of the annular air gap can be different, which facilitates the processing of the first conductive cylinders <NUM> and the second conductive cylinders <NUM>.

In the embodiment, a third air gap <NUM> extending along the axial direction of the rotor shaft <NUM> is formed between the second conductive cylinder <NUM> closest to the rotor shaft <NUM> among the second conductive cylinders <NUM> and outer peripheral surface of the rotor shaft <NUM>. An adjustment capacitance of a predetermined value is formed between the innermost second conductive cylinder <NUM> and the rotor shaft <NUM>, and the adjustment capacitance is connected in parallel with the bearing capacitances Cb1 and Cb2.

In the embodiment, the cross-sectional shapes of the second air gap <NUM> and the third air gap <NUM> in the radial direction is a circular ring shape concentric with the rotor shaft <NUM>. The second air gap <NUM> and the third air gap <NUM> of circular ring shapes form an adjustment capacitance of a predetermined value, and the adjustment capacitance is connected in parallel with the bearing capacitances Cb1 and Cb2 to effectively reduce the shaft voltage and shaft current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>.

In the embodiment, the distance in the radial direction of the second air gap <NUM> is less than or equal to <NUM>; the distance in the radial direction of the third air gap <NUM> is less than or equal to <NUM>, which can allow the value of the adjustment capacitance C3 relatively large. The adjustment capacitance C3 is connected in parallel to the bearing capacitances Cb1 and Cb2 to increase the equivalent capacitance Cb, so that the two ends of the equivalent capacitance Cb obtain a smaller divided voltage, that is, the voltage difference between the bearing inner ring <NUM> and the bearing outer rings <NUM> is reduced, and the shaft voltage is reduced. At the same time, the adjustment capacitance C3 is arranged larger than the bearing capacitances Cb1 and Cb2, so that the electricity at both ends of the equivalent capacitance Cb can be more concentrated on both ends of the adjustment capacitance C3, which is equivalent to concentrated between the first conductive cylinder <NUM> and the second conductive cylinder <NUM> and between the innermost second conductive cylinder <NUM> and the rotor shaft <NUM> to reduce shaft current.

In another embodiment of the present application, the electrode structure <NUM> further includes a shaft mounting portion <NUM> and an end plate <NUM> connecting the shaft mounting portion <NUM> and the first conductive cylinders <NUM>. The shaft mounting portion <NUM> is fixed on the rotor shaft <NUM> and is electrically connected to the rotor shaft <NUM>. The structure of the shaft mounting portion <NUM>, the end plate <NUM> and the first conductive cylinders <NUM> is easy to be assembled. The shaft mounting portion <NUM> is fixed to the rotor shaft <NUM> and is electrically connected to the rotor shaft <NUM>. This solution is easy to be assembled and ensures that the first conductive cylinders <NUM> are electrically connected to the rotor shaft <NUM>.

In the embodiment, the first conductive cylinders <NUM> are electrically connected to the shaft mounting portion <NUM> through the end plate <NUM>, so that all the first conductive cylinders <NUM> are electrically connected to the rotor shaft <NUM> through the shaft mounting portion <NUM>.

Referring to <FIG> and <FIG>, in another embodiment of the present application, the electrode structure <NUM> includes a conductive electrode plate <NUM> connected to the rotor shaft <NUM> and extending radially along the rotor shaft <NUM>, which is equivalent to adding a conductive electrode plate with the same potential as the rotor shaft <NUM> on the rotor shaft <NUM>. The bearing bracket <NUM> close to the conductive electrode plate <NUM> is a metal member. The area of the bearing bracket <NUM> close to the conductive electrode plate <NUM> is equivalent to adding an electrode plate with the same potential as the bearing outer ring <NUM> on the bearing outer ring <NUM>. A fourth air gap <NUM> is formed between the conductive electrode plate <NUM> and the bearing bracket <NUM>. An adjustment capacitance C3 is formed between the two electrode plates, and the rotor shaft <NUM> is electrically connected to the bearing inner ring <NUM>. Therefore, the adjustment capacitance C3 is equivalent to being connected in parallel between the bearing outer ring <NUM> and the bearing inner ring <NUM>. On the one hand, the shaft voltage between the bearing outer ring <NUM> and the bearing inner ring <NUM> can be reduced; on the other hand, the shaft current can be shunted, such that the current between the bearing bracket <NUM> and the rotor shaft <NUM> is shunted from the branch of the above-mentioned adjustment capacitance C3, which effectively reduce the shaft current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>. The electrode structure <NUM> also includes a shaft mounting portion <NUM> for connecting with the rotor shaft <NUM>.

In the embodiment, the distance in the axial direction of the fourth air gap <NUM> is less than or equal to <NUM>, such that the value of the adjustment capacitance C3 is relatively large. The adjustment capacitance C3 is connected in parallel to the bearing capacitances Cb1 and Cb2 to increase the equivalent capacitance Cb, so that the two ends of the equivalent capacitance Cb obtain a smaller divided voltage, that is, the voltage difference between the bearing inner ring <NUM> and the bearing outer rings <NUM> is reduced, and the shaft voltage is reduced. At the same time, the adjustment capacitance C3 is arranged larger than the bearing capacitances Cb1 and Cb2 can make the electricity at both ends of the equivalent capacitance Cb more concentrated on the two ends of the adjustment capacitance C3, which is equivalent to being concentrated on the bearing bracket <NUM> and the conductive electrode plate <NUM> to reduce the shaft current.

Referring to <FIG>, in another embodiment of the present application, the shaft mounting portion <NUM> is fixed at one end of the rotor shaft <NUM>, the end of the rotor shaft <NUM> is provided with a shaft hole <NUM> along the axial direction, and the shaft mounting portion <NUM> includes a fixing post <NUM> disposed toward the side of the bearing bracket <NUM> and matched with the shaft hole <NUM>, and the fixing post <NUM> is at least partially fixed to the shaft hole <NUM>. After the fixing post <NUM> is fixed to the shaft hole <NUM>, the first conductive cylinders <NUM> can be mounted on the rotor shaft <NUM> and electrically connected with the rotor shaft <NUM>, which is convenient for assembly and disassembly. The motor shown in <FIG> is another embodiment in which the fixing post <NUM> and the shaft hole <NUM> are provided.

In another embodiment of the present application, the fixing post <NUM> is fixed to the shaft hole <NUM> by crimping. The crimping method assembly can tightly fix the fixing post <NUM> in the shaft hole <NUM>, ensuring the reliability of the first conductive cylinders <NUM> connected to the rotor shaft <NUM> when the motor is working, and avoiding the first conductive cylinders <NUM> from detaching when the rotor shaft <NUM> rotates.

In another embodiment of the present application, the outer peripheral surface of the fixing post <NUM> is provided with an external thread, and the shaft hole <NUM> is provided with an internal thread that is threaded with the external thread. The first conductive cylinders <NUM> are fixedly mounted on the rotor shaft <NUM> through threaded connection, and the connection is firm and reliable.

In another embodiment of the present application, rollers <NUM> and grease are provided between the bearing outer ring <NUM> and the bearing inner ring <NUM>. The capacitance formed mainly depends on the oil film. When the bearing <NUM> is stationary, the bearing capacitance is larger. After rotating, the higher the speed and the more uniform, the more uniform the bearing oil film is formed, and the smaller the corresponding bearing capacitance. Generally, after the speed exceeds 1500r/min, the bearing capacitance value is basically stable. According to the actual measurement of a commonly used <NUM> bearing, the bearing capacitances corresponding to 1000r/min, 1500r/min and 2000r/min are 55PF, 33PF, and 32PF respectively. That is, the basic value of the bearing capacitance is above 30PF. The electrode structure <NUM> is provided, and an adjustment capacitance C3 is formed between the electrode structure <NUM> shown in <FIG> and <FIG> and the rotor shaft <NUM>, and an adjustment capacitance C3 is formed between the bearing bracket <NUM> and the electrode structure <NUM> shown in <FIG>. The adjustment capacitance C3 is an air capacitance, and the relative dielectric constant and absolute dielectric constant of air are constant. Therefore, it is the distance and the facing area of the air gap that determines the adjustment capacitance C3. If the ratio of the facing area on both sides of the air gap to the distance of the air gap is greater than or equal to <NUM>, the adjustment capacitance C3 greater than <NUM> PF can be formed. Furthermore, the adjustment capacitance C3 is greater than or much greater than the bearing capacitances Cb1 and Cb2, so that the electricity at both ends of the equivalent capacitance Cb can be more concentrated on both ends of the capacitance C3, which is equivalent to concentrated on the electrode structure <NUM> and the rotor shaft <NUM> (the first solution), or equivalent to concentrate on the electrode structure <NUM> and the bearing bracket <NUM> (the second solution), so that most of the current between the bearing bracket <NUM> and the rotor shaft <NUM> flows through the branch of the adjustment capacitance C3, to shunt the shaft current, thereby greatly reducing the current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>, that is, the shaft current. Therefore, the risk of electrical corrosion damage to the bearing <NUM> can be greatly reduced.

Specifically, referring to <FIG> and <FIG>, when the first air gap <NUM> is formed between the sleeve portion <NUM> and the rotor shaft <NUM>, the ratio of the facing area of the first air gap <NUM> to the distance of the first air gap <NUM> is greater than or equal to <NUM>. Furthermore, the adjustment capacitance C3 is arranged larger or far larger than the bearing capacitances Cb1 and Cb2, so as to achieve the above-mentioned effect of reducing the shaft current and reducing the electric corrosion of the bearing <NUM>.

Referring to <FIG>, when a second air gap <NUM> is formed between the first conductive cylinder <NUM> and the second conductive cylinder <NUM>, and a third air gap 612is formed between the innermost second conductive cylinder <NUM> and the outer circumferential surface of the rotor shaft <NUM>, the sum of the ratio of the facing area to the distance of the second air gap <NUM> and the ratio of the facing area to the distance of the third air gap <NUM> is greater than or equal to <NUM>. Furthermore, the adjustment capacitance C3 is greater than or far greater than the bearing capacitances Cb1 and Cb2, so as to achieve the above-mentioned effect of reducing the shaft current and reducing the electric corrosion of the bearing <NUM>.

Referring to <FIG>, when a fourth air gap <NUM> is formed between the conductive electrode plate <NUM> and the bearing bracket <NUM>, the ratio of the facing area to the distance of the fourth air gap <NUM> is greater than or equal to <NUM>. Furthermore, the adjustment capacitance C3 is arranged larger or far larger than the bearing capacitances Cb1 and Cb2, so as to achieve the above-mentioned effect of reducing the shaft current and reducing the electric corrosion of the bearing <NUM>.

In another embodiment of the present application, the electrode structure <NUM> is a metal member integrally molded, which can be easily processed by an integrally molded process. Specifically, the electrode structure <NUM> may be made of aluminum or other metal members, which can realize conductivity and is easy to be formed.

In another embodiment of the present application, an electrical equipment is provided, including the above-mentioned motor.

In the loop of the high-frequency circuit, there is also a capacitance Cb between the bearing outer ring <NUM> and the bearing inner ring <NUM>. The shaft voltage is the divided voltage between the two ends of the capacitance Cb. The capacitance Cd is equivalent to being connected in series on the outer ring side of the bearing of the capacitance Cb. Therefore, the capacitance Cd is reduced through the arrangement of the bracket insulation layer <NUM>, so that the two ends of the capacitance Cb obtain a smaller divided voltage, that is, the shaft voltage is reduced, and the risk of electric corrosion of the bearing is effectively reduced. For motors with larger power and larger metal shells to increase the installation strength and ensure heat dissipation, the risk of electrical corrosion damage to the motor bearings <NUM> can also be reduced.

The electrode structure <NUM> is used to adjust the equivalent capacitance Cb between the bearing inner ring <NUM> and the bearing outer ring <NUM>. The electrode structure <NUM> is electrically connected to the bearing bracket <NUM> and forms an adjustment capacitance C3 with the rotor shaft <NUM>; or, the electrode structure <NUM> is electrically connected to the rotor shaft <NUM> and forms an adjustment capacitance C3 with the bearing bracket <NUM>. The adjustment capacitance C3 is connected in parallel with the bearing capacitances Cb1 and Cb2 to increase the equivalent capacitance Cb and reduce the voltage difference between the two ends of the equivalent capacitance Cb. On the one hand, the parallel connection of the adjustment capacitance C3 will increase the equivalent capacitance Cb, such that the equivalent capacitance Cb obtain a smaller divided voltage, that is, the voltage difference between the bearing inner ring <NUM> and the bearing outer ring <NUM> is reduced, and the decreasing of the shaft voltage is realized. On the other hand, when the adjustment capacitance C3 is relatively large relative to the bearing capacitances Cb1 and Cb2, the current between the bearing bracket <NUM> and the rotor shaft <NUM> will flow through the branch of the adjustment capacitance C3 to shunt the shaft current, thereby reducing the current flowing through the bearing outer ring <NUM> and the bearing inner ring <NUM>, that is, the shaft current, and therefore, the risk of electrical corrosion damage to the bearing <NUM> can be greatly reduced.

Claim 1:
A motor, comprising:
a stator (<NUM>), comprising a stator core (<NUM>) provided with windings (<NUM>);
a rotor (<NUM>), rotatably mounted with respect to the stator (<NUM>), wherein the rotor (<NUM>) comprises a rotor core (<NUM>) and a rotor shaft (<NUM>) located at a center of the rotor core (<NUM>) and connected to the rotor core (<NUM>);
a bearing (<NUM>), supporting the rotor shaft (<NUM>), and comprising a bearing inner ring (<NUM>) and a bearing outer ring (<NUM>);
a bearing bracket (<NUM>), comprising a bearing support portion (<NUM>) made of conductive material and configured for fixing and conducting the bearing outer ring (<NUM>); wherein at least one bearing bracket (<NUM>) further comprises a stator bracket portion (<NUM>) made of conductive material and configured for connection to the stator (<NUM>), the stator bracket portion (<NUM>) is located on the radially outer side of the bearing support portion (<NUM>), and a bracket insulation layer (<NUM>) is provided between the bearing support portion (<NUM>) and the stator bracket portion (<NUM>); characterised by
an electrode structure (<NUM>), configured for adjusting an equivalent capacitance between the bearing inner ring (<NUM>) and the bearing outer ring (<NUM>); wherein the electrode structure (<NUM>) is electrically connected with the bearing bracket (<NUM>) and an adjustment capacitance is formed between the electrode structure (<NUM>) and the rotor shaft (<NUM>) or the electrode structure (<NUM>) is electrically connected with the rotor shaft (<NUM>), and an adjustment capacitance is formed between the electrode structure (<NUM>) and the bearing bracket (<NUM>);
wherein two bearings (<NUM>) are provided, and the two bearings (<NUM>) are arranged on both sides of the rotor core (<NUM>) at intervals along an axial direction of the rotor core (<NUM>), and each of the bearings is connected to one bearing bracket (<NUM>), and wherein the bearing support portions (<NUM>) of the two bearing brackets (<NUM>) are electrically connected by a conductive member (<NUM>) and the conductive member (<NUM>) is insulated from the stator bracket portion (<NUM>).