JP2008048467A - Rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce vibrations transmitted from a stator to a casing. <P>SOLUTION: A rotary electric machine 100 includes a motor casing 104 that stores a rotor and a stator 102, a bolt 200 that passes through the stator 102 in the direction parallel to the rotating shaft of the rotary electric machine 100 and that is fastened to the motor casing 104, and a nut 222 that has a shape corresponding to the shaft portion of the bolt 200. A space 108 is formed inside the motor casing 104 and around the shaft of the inserted portion of the bolt 200. The nut 222 is provided inside the space 108. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine including a rotor and a stator, and more particularly to a structure for fixing a stator to a casing that reduces transmission of vibration generated in the stator to the casing.

  HV (Hybrid Vehicle), EV (Electric Vehicle), and FCV (Fuel Cell Vehicle) vehicles are equipped with a rotating electrical machine as a drive source. The rotating electrical machine includes a rotor, a stator, and a casing. In such a rotating electric machine, a structure in which a stator is fastened to a casing by a bolt is known.

  For example, Japanese Patent Laying-Open No. 2000-236639 (Patent Document 1) discloses a brushless motor rotor that can reduce the weight of a rotor core and suppress thermal demagnetization of a permanent magnet attached to the rotor core. Disclose. The rotor includes a cylindrical rotor core, a rotor shaft that passes through the center of the rotor core, and the rotor core is fixed to the outer periphery of the rotor core in the circumferential direction of the rotor core. And two or more permanent magnets intermittently attached along the rotor shaft, and a plurality of air holes provided between the rotor shaft and the permanent magnet and penetrating in the thickness direction of the rotor core. It is characterized by doing.

According to the rotor of the brushless motor disclosed in the above-mentioned publication, a plurality of air holes located between the rotor shaft and the permanent magnet are provided through the rotor core in the thickness direction. While being able to reduce, since a rotor core can be cooled and the temperature rise can be suppressed by the gas which passes through each ventilation hole during the rotational motion of a rotor, the thermal demagnetization of a permanent magnet can be suppressed.
Japanese Patent Application Laid-Open No. 2000-236639

  However, in the brushless motor disclosed in the above-mentioned publication, the stator and the casing are fastened by screws, so that the stator is fixed to the casing.

  When electric power is supplied to the coil wound around the stator, a magnetic field is generated in the stator. Based on the generated magnetic field, a magnetic flux is formed between the rotor and the stator, so that a rotational force is generated in the rotor. When a rotational force is developed in the rotor, the stator receives a reaction force against the rotational force developed in the rotor. When the rotating electrical machine operates, the stator vibrates based on the received reaction force.

  Therefore, when the stator is fixed to the casing, there is a problem that resonance between the stator and the casing occurs. As a result, in a vehicle in which a rotating electrical machine is mounted as a drive source, there is a problem that noise is generated from components of the drive system (for example, a transaxle).

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a rotating electrical machine that reduces vibrations transmitted from a stator to a casing.

  A rotating electrical machine according to a first aspect is a rotating electrical machine including a rotor and a stator. The rotating electrical machine has a shape corresponding to a housing that houses the rotor and the stator, a bolt that passes through the stator in a direction parallel to the rotating shaft of the rotating electrical machine and is fastened to the housing, and a shaft portion of the bolt. And having a nut. A space portion is formed inside the housing and around the axis of the bolt insertion portion. The nut is provided in the space.

  According to the first invention, when the rotating electrical machine is operated, a magnetic field is generated in the stator in accordance with the power supply to the coil wound around the stator. A rotational force is developed in the rotor based on the magnetic field generated in the stator. At this time, a reaction force against the rotational force developed in the rotor is applied to the stator. For this reason, the stator vibrates based on the received reaction force. The vibration component generated according to the reaction force includes at least a component in a direction orthogonal to the rotation axis. Further, the vibration generated in the stator is transmitted not only to the casing via the contact surface between the stator and the casing but also to the casing via the bolt. The bolt penetrates the stator in a direction parallel to the rotation axis. A space is formed around the axis of the portion where the bolt is inserted into the housing, and a nut is fastened in the space. The position of the shaft portion of the bolt is limited by friction based on the fastening force between the nut and the housing. Therefore, when the vibration of the stator is transmitted to the housing via the bolt, the housing and the nut are allowed to move relative to each other in the direction perpendicular to the rotation axis. At this time, the vibration of the stator is absorbed by heat conversion due to friction on the contact surface between the nut and the housing. That is, by forming a space portion inside the housing and providing a nut in the space portion, the vibration of the stator transmitted to the housing via the bolt can be reduced. Thereby, since the vibration level at the resonance frequency can be reduced, it is possible to reduce noise generated during operation of the rotating electrical machine. Therefore, it is possible to provide a rotating electrical machine that reduces vibrations transmitted from the stator to the housing.

  In the rotating electrical machine according to the second invention, in addition to the configuration of the first invention, the space portion is a relative movement range in a direction perpendicular to the rotating shaft of the rotating electrical machine between the bolt shaft and the housing. Is formed in a shape that is not limited by the nut.

  According to the second aspect of the present invention, the relative movement range in the direction orthogonal to the rotation axis of the bolt shaft and the housing is formed in a shape that is not limited by the nut, so that the nut and the housing are relative to each other. When moving smoothly, the movement range is not limited by the nut, so that the vibration of the stator transmitted to the housing can be reliably reduced.

  In the rotating electrical machine according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the space portion has an opening that opens on the axial center side of the rotating shaft.

  According to the third invention, the stator can be fastened to the casing by inserting the nut from the opening and inserting the bolt into the stator and the casing.

  In the rotating electrical machine according to the fourth invention, in addition to the configuration of any one of the first to third inventions, an opening is formed in the housing. The shaft portion of the bolt is inserted into the space through the opening. A gap is formed in the direction perpendicular to the rotation axis of the rotating electrical machine at the shaft portion and the opening of the bolt that penetrates the space.

  According to the fourth invention, a gap having a predetermined distance is formed in the direction perpendicular to the rotation axis between the shaft portion of the bolt and the opening. Thereby, relative movement between the shaft portion of the bolt and the housing is possible. Therefore, the vibration of the stator is transmitted to the housing through the shaft portion of the bolt and the nut. This can be reduced by relatively moving the housing and the nut and converting the vibration from the stator into heat due to the friction between the housing and the nut.

  A rotating electrical machine according to a fifth invention is mounted on a vehicle in addition to the configuration of any one of the first to fourth inventions.

  According to the fifth aspect, by applying the present invention to a vehicle on which a rotating electrical machine is mounted, vibrations transmitted from the stator to the housing are reduced, so that noise generated during operation of the rotating electrical machine is also reduced. . Therefore, noise generated in the vehicle is reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As shown in FIG. 1, a rotating electrical machine 100 according to the present embodiment includes a stator 102, a motor case 104 that is a casing, and a rotor (not shown).

  The stator 102 has a hollow cylindrical shape. In the present embodiment, stator 102 is formed by laminating a plurality of electromagnetic steel plates along the rotation axis direction. In the stator 102, a plurality of teeth and slots (both not shown) are formed toward the axial center side.

  The plurality of slots are formed by grooves penetrating in a direction parallel to the rotation axis. The plurality of teeth are formed between the slots along a direction parallel to the rotation axis. A coil (not shown) is wound around each tooth.

  The rotor has a cylindrical shape and is inserted into a hollow portion inside the stator 102. The outer diameter of the rotor is at least smaller than the inner diameter inside the stator 102. The rotor is fixed to a rotating shaft (not shown). The rotating shaft is rotatably supported on the rotating shaft of the rotating electrical machine 100 by a bearing portion (not shown) provided in the motor case 104.

  The rotor is formed, for example, by inserting a permanent magnet in a direction parallel to the rotation axis with respect to a cylindrical laminated body in which a plurality of electromagnetic steel plates are laminated. A plurality of permanent magnets are inserted along the circumferential direction. In addition, it may replace with a permanent magnet and you may make it comprise a rotor using an electromagnet.

  The motor case 104 has a hollow cylindrical shape, and accommodates the stator 102 and the rotor in an inner hollow portion. The material of the motor case 104 is, for example, an aluminum alloy, but is not particularly limited thereto.

  The motor case 104 is formed with an attachment surface 106 that fixes the stator 102 to the inside. The mounting surface 106 has a smaller inner diameter than the outer diameter of the stator 102 and is a surface that is formed along the inner periphery of the motor case 104 and is orthogonal to the rotation axis. Three openings 110 are formed in the mounting surface 106. The openings 110 are formed at equal intervals in the circumferential direction around the rotation axis.

  Further, the stator 102 is formed with protruding portions 112, 114, 116 having through holes 120, 122, 124 at positions corresponding to the three openings 110. FIG. 2 shows an arrow A in FIG. As shown in FIG. 2, protrusions 112, 114, 116 are provided on the outer edge of the stator 102 at equal intervals around the rotation axis along the circumferential direction. The protrusions 112, 114, and 116 have a shape protruding in the radial direction.

  The protrusions 112, 114, and 116 are formed along a direction parallel to the rotation axis. In addition, through holes 120, 122, and 124 are formed in the protrusions 112, 114, and 116 in a direction parallel to the rotation axis. A bolt 200 is inserted into each of the through holes 120, 122, and 124. The bolt 200 inserted into the stator 102 is inserted into the opening 110 formed in the mounting surface 106.

  The opening 110 is formed so as to communicate with a space 108 formed inside the motor case 104. A nut (not shown) is provided in the space 108. The nut has a shape corresponding to the bolt 200. Stator 102 is fastened to mounting surface 106 of motor case 104 by bolts 200 and nuts.

  In the present embodiment, it has been described that three openings 110 are formed on the mounting surface 106 and three protrusions 112, 114, 116 are formed on the stator 102, but the number is particularly limited to three. It is not a thing.

  In such a rotating electric machine structure, when electric power is supplied to the coil wound around the stator 102, a magnetic field is generated in the stator 102. A magnetic flux flow is formed between the rotor and the stator 102 based on the generation of the magnetic field. And a rotational force expresses in a rotor by the flow of the formed magnetic flux.

  When a rotational force is developed in the rotor, the stator 102 receives a reaction force against the rotational force developed in the rotor. As a result, vibration is generated in the stator 102. When the vibration generated in the stator 102 is transmitted to the motor case 104, resonance between the stator 102 and the motor case 104 may occur, resulting in noise of the rotating electrical machine 100. In particular, in a relatively lightweight case such as an aluminum alloy, noise due to vibration generated in the stator 102 tends to increase.

  Therefore, the present invention is characterized in that a space portion 108 is formed inside the motor case 104 and around the axis of the insertion portion of the bolt 200, and a nut is provided in the space 108.

  FIG. 3 shows a 3-3 cross section of FIG. As shown in FIG. 3, an opening 110 is formed in the mounting surface 106 in a direction parallel to the rotation axis. Further, a space 108 is formed on the end side of the motor case 104 with respect to the mounting surface 106. The space 108 communicates with the opening 110. Further, the space portion 108 is opened toward the axial center side by the opening portion 224.

  The space portion 108 is formed in a substantially rectangular shape from the axial center side toward the radially outer side. A nut 222 is provided in the space 108. The stator 102 is fastened to the mounting surface 106 of the motor case 104 by the bolt 200 and the nut 222.

  FIG. 4 shows an enlarged perspective view of the broken-line frame in FIG. 4 illustrates the nut 222, the space 108, and the inner diameter surface of the opening 110 for convenience of explanation. As shown in FIG. 4, in a state in which the nut 222 is fastened to the shaft portion of the bolt 200, the shaft portion of the bolt 200 is friction based on the fastening force at the contact surface 226 between the nut 222 and the motor case 104. As a result, the position is limited. The surface roughness of the contact surfaces of the nut 222 and the motor case 104 may be adjusted to an appropriate surface roughness through experiments or the like in advance.

  Further, a gap is formed between the shaft portion of the bolt 200 and the opening 110 formed in the motor case 104 in a direction perpendicular to the shaft of the bolt 200. The gap is not particularly limited as long as the shaft portion of the bolt 200 can be inserted into the opening 110. For example, a gap of a predetermined distance is formed between the shaft portion of the bolt 200 and the opening 110. You may make it have.

  The length of the opening 224 and the space 108 in the axial direction of the bolt 200 is substantially the same as the length of the nut 222 in the axial direction, and is at least long enough for the nut 222 to be accommodated in the space 108. Have.

  Further, the space 108 is formed in a shape such that the relative movement range in the direction perpendicular to the rotation axis is not limited by the nut 222 in the shaft portion of the bolt 200 and the motor case 104. For example, the space portion 108 is formed in a substantially rectangular shape having a size such that the nut 222 does not contact the wall surface of the space portion 108 even when the nut 222 and the motor case 104 move relative to each other.

  The operation based on the structure of the rotating electrical machine 100 as described above will be described. When the stator 102 is fastened to the motor case 104 by the bolt 200 and the nut 222, the stator 102 is supported by the contact surface between the motor case 104 and the stator 102.

  When electric power is supplied to the coil wound around the stator 102 and a rotational force is developed in the rotor, the stator 102 receives a reaction force with respect to the rotational force developed in the rotor. When the rotating electrical machine 100 is operated, the stator 102 vibrates by this reaction force. The vibration component at this time includes at least a component in a direction orthogonal to the rotation axis. At this time, the vibration transmitted to the bolt 200 causes a slip at the contact surface 226 between the nut 222 and the motor case 104. Therefore, the vibration transmitted from the stator 102 is thermally converted by the friction generated on the contact surface 226 between the nut 222 and the motor case 104 and reduced.

  The direction orthogonal to the rotation axis is, for example, the direction around the axis of the bolt 200, the radial direction of the stator 102, and the circumferential direction of the stator 102, but is not particularly limited thereto.

  In this way, a space portion is formed inside the motor case 104, and the stator 102 and the motor case 104 are interposed between the stator 102 and the motor case 104 by fastening the stator 102 to the mounting surface 106 with the bolts 200 and the nuts 222. Compared to the case where the case 104 is fixed, a change such as a decrease in spring rigidity can be caused.

  Therefore, the vibration level at the resonance frequency is reduced. Further, during the operation of the rotating electrical machine 100, since slip always occurs between the nut 222 and the motor case 104, vibration is always absorbed.

  As described above, according to the rotating electrical machine according to the present embodiment, the space is formed around the axis of the portion where the bolt is inserted into the motor case, and the nut is fastened in the space. The position of the shaft portion of the bolt is limited by friction based on the fastening force between the nut and the motor case. Therefore, when the vibration of the stator is transmitted to the motor case via the bolt, relative movement between the motor case and the nut is allowed. At this time, the vibration of the stator is absorbed by heat conversion due to friction on the contact surface between the nut and the motor case. That is, by forming a space inside the motor case and providing a nut in the space, it is possible to reduce the vibration of the stator transmitted to the motor case via the bolt. Thereby, since the vibration level at the resonance frequency can be reduced, it is possible to reduce noise generated during operation of the rotating electrical machine. Therefore, it is possible to provide a rotating electrical machine that reduces vibrations transmitted from the stator to the housing.

  The rotating electrical machine as described above is mounted on a vehicle. In this way, noise generated during operation of the rotating electrical machine is reduced, so that noise generated in the vehicle is also reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the structure of the stator and motor case of the rotary electric machine which concerns on this Embodiment. It is an external view of a stator and a motor case viewed from an arrow A. FIG. 3 is a 3-3 cross section of FIG. 2. It is an expansion perspective view of the broken-line frame of FIG.

Explanation of symbols

  100 rotating electrical machine, 102 stator, 104, 404 motor case, 106 mounting surface, 108 space, 110, 224 opening, 112, 114, 116 protrusion, 120, 122, 124 through hole, 222 nut, 226 contact surface, 200 volts.

Claims (5)

A rotating electric machine comprising a rotor and a stator,
A housing for housing the rotor and the stator;
A bolt that penetrates the stator in a direction parallel to the rotation axis of the rotating electrical machine and is fastened to the housing;
A nut having a shape corresponding to the shaft portion of the bolt,
A space is formed inside the housing and around the axis of the insertion portion of the bolt,
The nut is a rotating electrical machine provided in the space.   The space portion is formed in a shape such that a relative movement range in a direction perpendicular to a rotation axis of the rotating electrical machine is not limited by the nut in the bolt shaft and the housing. The rotating electrical machine described in 1.   The rotating electrical machine according to claim 1, wherein the space portion has an opening that opens to an axial center side of the rotation shaft. An opening is formed in the housing, and a shaft portion of the bolt is inserted into the space through the opening,
The rotating electrical machine according to any one of claims 1 to 3, wherein a gap of a predetermined distance is formed in a direction orthogonal to the rotating shaft of the rotating electrical machine between the shaft portion of the bolt and the opening.   The rotating electrical machine according to claim 1, wherein the rotating electrical machine is mounted on a vehicle.

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