Patent Description:
One example of conventional rotors of rotating electric machines having permanent magnets includes a magnet holder having a holder base provided to a rotary shaft, a plurality of holder arms formed so as to protrude from the holder base in the axial direction of the rotary shaft, and elastic bridge portions connecting the holder base and the holder arms (see, for example, <CIT>).

Another document is <CIT> which refers to an electric motor with a rotor having a rotating body, which rotating body further includes a plurality of axial arms molded to the corresponding slots and configured to fix the permanent magnets.

However, in the rotor described in <CIT> , positioning and fixation of magnets in the circumferential direction are made by elasticity of the bridge portions. Therefore, there is a possibility that positioning accuracy of permanent magnets in the circumferential direction is deteriorated, thus causing cogging torque and torque ripple. In addition, such cogging torque and torque ripple might deteriorate performance of a rotating electric machine.

The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide a rotor of rotating electric machine, and a rotating electric machine, that enable improvement in positioning accuracy for magnets in the circumferential direction.

A rotor of rotating electric machine is provided according to claim <NUM>.

The rotor of rotating electric machine according to the present disclosure enables improvement in positioning accuracy for magnets in the circumferential direction.

Embodiments of a rotor of rotating electric machine, and a rotating electric machine, according to the present disclosure, will be described below with reference to the drawings. In the drawings, the same or similar components are denoted by the same reference characters. For the purpose of avoiding unnecessary redundant description and facilitating the understanding of the skilled person, detailed description of a well-known matter and repetitive description of substantially the same configuration may be omitted.

Embodiment <NUM> will be described with reference to <FIG>. <FIG> is a sectional view of a rotating electric machine in embodiment <NUM>. A rotating electric machine <NUM> mainly includes a rotor <NUM> (i.e., rotor of rotating electric machine) stored in a hollow cylindrical motor case <NUM>, a stator <NUM>, and an output shaft <NUM> penetrating the rotor <NUM>. The rotor <NUM> is fixed to the output shaft <NUM>, and the outer circumferential surface of the rotor <NUM> is opposed to the inner circumferential surface of the stator <NUM> with an air gap therebetween. On the outer circumferential surface of the rotor <NUM>, a plurality of pairs of permanent magnets (not shown) are arranged for forming field poles at the outer circumferential surface of the rotor <NUM>.

The stator <NUM> is wound with armature windings <NUM> for three phases (U phase, V phase, W phase). An annular wiring portion <NUM> is provided near the upper side of the armature windings <NUM> in <FIG>. Although not shown, the armature windings <NUM> and the annular wiring portion <NUM> are connected by welding or the like via upper ends of the armature windings <NUM>. A winding end <NUM> provided at the annular wiring portion <NUM> extends so as to penetrate a frame <NUM> described later in an extending direction of the axial line of the rotating electric machine <NUM>, i.e., the axial direction of the output shaft <NUM>. The winding end <NUM> is connected to the armature winding <NUM> via the annular wiring portion <NUM>. In the following description, an "output-shaft direction" refers to the axial direction of the output shaft <NUM>, a "radial direction" refers to the radial direction of the output shaft <NUM>, and a "circumferential direction" refers to the circumferential direction of the output shaft <NUM>.

The winding end <NUM> is formed such that three conductors respectively connected to an end of the U-phase winding, an end of the V-phase winding, and an end of the W-phase winding of the armature windings <NUM> are collected.

On the upper and lower sides of the rotor <NUM> in <FIG>, a pair of first bearings 9a and a pair of second bearings 9b for rotatably supporting the output shaft <NUM> are provided, respectively. The first bearings 9a are provided at a center part of the frame <NUM>. The frame <NUM> serves as a cover for closing the inside of the rotating electric machine <NUM>. The second bearings 9b are fixed to a structure <NUM> on an output side of the rotating electric machine <NUM>.

A sensor rotor <NUM> is fixed at an end on a non-output side of the output shaft <NUM> (side opposite to the side where the output-side structure <NUM> is located). A rotation sensor (not shown) is provided at a non-output-side end surface of the sensor rotor <NUM> with a gap therebetween. The sensor rotor <NUM> has one pair or a plurality of pairs of permanent magnets. The rotation sensor located separately from the sensor rotor <NUM> detects change in a magnetic field generated from the permanent magnets of the sensor rotor <NUM> rotating along with rotation of the output shaft <NUM>, converts the detected change into an electric signal, and transmits the electric signal to a control device (not shown) of the rotating electric machine <NUM>, or the like. Although the sensor rotor <NUM> and the rotation sensor are described as a magnetic sensor type here, a type other than the magnetic sensor type may be used, e.g., a resolver may be used. Alternatively, a Hall sensor may be used.

<FIG> is an exploded perspective view of the rotor in embodiment <NUM>. A rotor core <NUM> is fixed to the output shaft <NUM>, and magnets <NUM> which are segment-type permanent magnets are attached to the outer circumference of the rotor core <NUM>. The magnets <NUM> are attached to the rotor core <NUM> by magnet holders <NUM> made of synthetic resin, for example, so as to be positioned and fixed. The number of the magnet holders <NUM> is the same as the number of the magnets <NUM> attached to the rotor core <NUM>. A hollow cylindrical cover <NUM> is attached on the outer side of the magnets <NUM>. The cover <NUM> has a function of preventing a fraction of the magnet <NUM> from flying off to a surrounding area when the magnet <NUM> is damaged, and thus preventing the rotating electric machine <NUM> from being locked by the fraction of the magnet <NUM>. The rotor <NUM> in embodiment <NUM> has a stage-skewed structure such that the rotor <NUM> has two-stage rotor cores <NUM> shifted from each other in the circumferential direction. The magnet holders <NUM> provided to the rotor cores <NUM> all have the same shape. In embodiment <NUM>, at one rotor core <NUM>, eight magnets <NUM> are attached along the circumferential direction of the rotor core <NUM>. Therefore, in the entire rotor <NUM>, eight magnets <NUM> are arranged in each of two rows. Since the rotor <NUM> has a stage-skewed structure as described above, the magnets <NUM> having the same polarities in the adjacent rows are attached at positions shifted from each other by a predetermined step angle in the circumferential direction.

<FIG> is a perspective view of the magnet holder according to embodiment <NUM>. The magnet holder <NUM> has a base portion <NUM> of which one side is on the inner side in the radial direction of the output shaft <NUM> and the other side is on the outer side in the radial direction when the magnet holder <NUM> is attached to the rotor core <NUM>. The base portion <NUM> has a sector shape expanding from the inner side in the radial direction toward the outer side in the radial direction. On one surface of the base portion <NUM>, an arm portion <NUM> is provided at a center part on the outer side in the radial direction. The arm portion <NUM> is for retaining the magnet <NUM> in the radial direction and the circumferential direction and extends in the output-shaft direction.

On the surface on the arm portion <NUM> side of the base portion <NUM>, a press-fit pin <NUM> protrudes at a center part. The press-fit pin <NUM> is used for fixing the magnet holder <NUM> to the rotor core <NUM>. On the surface on the arm portion <NUM> side of the base portion <NUM>, an end on the outer side in the radial direction is raised toward the arm portion side so as to be stepped, thus forming an output-shaft-direction retaining portion <NUM> for retaining the magnet <NUM> in the output-shaft direction. The output-shaft-direction retaining portion <NUM> contacts with one-side end surface of the magnet <NUM> in the output-shaft direction so as to retain the magnet <NUM> in the output-shaft direction. A non-arm-portion side (side opposite to the arm portion <NUM> side) of a radial-direction outer end surface of the base portion <NUM> is tapered inward in the radial direction, thus forming a guide portion <NUM>. Owing to the guide portion <NUM>, the rotor core <NUM> can be easily stored in the cover <NUM> at the time of assembling the rotor <NUM>. In view of ease of molding of the magnet holder <NUM>, a through hole may be provided to the base portion <NUM> as appropriate.

The arm portion <NUM> retains the magnet <NUM> in the radial direction by a radial-direction inner surface 16a thereof. That is, as described later, when the magnet <NUM> is inserted between the rotor core <NUM> and the magnet holder <NUM>, the radial-direction inner surface 16a of the arm portion <NUM> contacts with the a radial-direction outer surface of the magnet <NUM>, thereby retaining the magnet <NUM> in the radial direction. The arm portion <NUM> is provided with a holder rib <NUM> for retaining a circumferential-direction side surface of the magnet <NUM>. The holder rib <NUM> protrudes inward in the radial direction from a circumferential-direction center part of the arm portion <NUM>. A cutout <NUM> is provided on the base portion <NUM> side of the holder rib <NUM>. The output-shaft-direction length of the cutout <NUM> is set to be greater than two times the length of the press-fit pin <NUM>. At an end of the holder rib <NUM> on a non-base-portion side (side opposite to the base portion <NUM> side), a come-off prevention protrusion <NUM> (i.e., a protrusion) is provided so as to protrude further inward in the radial direction from the holder rib <NUM>. The come-off prevention protrusion <NUM> is for preventing the magnet holder <NUM> from coming off in the circumferential direction when the magnet holder <NUM> is attached to the rotor core <NUM>.

<FIG> is a detailed view of the arm portion according to embodiment <NUM>, when the arm portion <NUM> shown in <FIG> is seen outward in the radial direction. The circumferential-direction width of the come-off prevention protrusion <NUM> is smaller at a base part thereof than at a distal end thereof, thus forming a constricted portion <NUM>. One surface in the circumferential direction of the holder rib <NUM> serves as a pressing surface <NUM>, and a surface of the holder rib <NUM> opposite to the pressing surface <NUM> serves as a relief surface <NUM>. As described later in detail, when the magnets <NUM> are attached to the rotor core <NUM>, the pressing surface <NUM> contacts with a circumferential-direction side surface of the magnet <NUM>, to press the magnet <NUM>, and the relief surface <NUM> is separate from the magnet <NUM> without contacting with the magnet <NUM>.

<FIG> is a perspective view of the rotor core according to embodiment <NUM>. At both ends in the output-shaft direction of an outer circumferential surface <NUM> of the rotor core <NUM> having substantially an octagonal prism shape, a plurality of core ribs <NUM> protruding outward in the radial direction are provided at predetermined intervals in the circumferential direction. The core ribs <NUM> are for positioning the magnets <NUM> by pressing the magnets <NUM>, and are provided at two locations for each magnet <NUM>. In embodiment <NUM>, since eight magnets <NUM> are attached to one rotor core <NUM>, the core ribs <NUM> are provided at sixteen locations for one rotor core <NUM>.

An insertion groove <NUM> and a lock groove <NUM> are provided between the core ribs <NUM> at two locations for each magnet <NUM>. The insertion groove <NUM> is a groove in which the come-off prevention protrusion <NUM> of the magnet holder <NUM> is to be inserted, and the circumferential-direction width of the insertion groove <NUM> is not less than the circumferential-direction width of the come-off prevention protrusion <NUM>. The lock groove <NUM> is a groove for preventing the come-off prevention protrusion <NUM> from coming off outward in the radial direction, and has such a shape to which the distal end of the come-off prevention protrusion <NUM> is fitted. The output-shaft-direction lengths of the insertion groove <NUM> and the lock groove <NUM> are greater than the output-shaft-direction length of each come-off prevention protrusion <NUM>. On an output-shaft-direction one-side end surface <NUM>, a plurality of press-fit holes <NUM> are provided at predetermined intervals in the circumferential direction. The press-fit hole <NUM> is a hole into which the press-fit pin <NUM> of the magnet holder <NUM> is to be press-fitted and fixed. In embodiment <NUM>, since eight magnets <NUM> are attached to the rotor core <NUM>, eight magnet holders <NUM> are attached. Therefore, eight press-fit holes <NUM> are provided. The output-shaft-direction lengths of the insertion groove <NUM> and the lock groove <NUM> may be changed as appropriate in a range not less than the output-shaft-direction length of the come-off prevention protrusion <NUM>. The distance between the output-shaft-direction one-side end surface <NUM> and the lock groove <NUM> is smaller than the distance between the base portion <NUM> and the come-off prevention protrusion <NUM> of the magnet holder <NUM>. Thus, when the press-fit pin <NUM> is press-fitted into the press-fit hole <NUM>, the come-off prevention protrusion <NUM> is fitted to the lock groove <NUM>.

<FIG> is a sectional view along line A-A in <FIG> and is a plan view of a first core plate according to embodiment <NUM>. <FIG> is a sectional view along line B-B in <FIG> and is a plan view of a second core plate according to embodiment <NUM>. <FIG> is a sectional view along line C-C in <FIG> and is a plan view of a third core plate according to embodiment <NUM>. The rotor core <NUM> is formed by stacking first core plates 33A, second core plates 33B, and third core plates 33C made of electromagnetic steel sheets and each having a thickness of about <NUM>, and then welding the stacking side surface. A plurality of first core plates 33A are stacked to form an end part of the rotor core <NUM> on the output-shaft-direction one-side end surface <NUM> side and the press-fit holes <NUM>. A plurality of second core plates 33B are stacked to form a center part of the rotor core <NUM> and the insertion grooves <NUM>. A plurality of third core plates 33C are stacked to form an end part of the rotor core <NUM> on the side opposite to the output-shaft-direction one-side end surface <NUM>, and the lock grooves <NUM>.

Next, a procedure for assembling the rotor <NUM> in embodiment <NUM> will be described. <FIG> shows the procedure for assembling the rotor in embodiment <NUM>. First, the come-off prevention protrusion <NUM> of the magnet holder <NUM> is inserted into the insertion groove <NUM> of the rotor core <NUM> from the outer side in the radial direction. Then, the magnet holder <NUM> is moved in the output-shaft direction so that the press-fit pin <NUM> is press-fitted and fixed into the press-fit hole <NUM> of the rotor core <NUM>. At this time, the magnet <NUM> is subsequently inserted in the output-shaft direction from the non-base-portion side of the magnet holder <NUM>. In embodiment <NUM>, eight magnets <NUM> are inserted for one rotor core <NUM>. Push-in surfaces <NUM> of the magnets <NUM> are pushed in simultaneously so as to be flush with an output-shaft-direction opposite-side end surface <NUM> of the rotor core <NUM>, whereby the magnets <NUM> are inserted into a gap <NUM> between the rotor core <NUM> and the magnet holders <NUM>. Here, the push-in surface <NUM> is an end surface of the magnet <NUM> on the non-base-portion side and is a surface to be pushed when the magnet <NUM> is inserted. The output-shaft-direction opposite-side end surface <NUM> is an output-side end surface on the side opposite to the output-shaft-direction one-side end surface <NUM>.

Next, the magnets <NUM> and the magnet holders <NUM> are attached also to another rotor core <NUM> through the same procedure, the two rotor cores <NUM> are arranged along the output-shaft direction with their centers aligned with each other, and the output shaft <NUM> is press-fitted into the center holes of the two rotor cores <NUM> having the magnets <NUM> attached thereto. At this time, the two rotor cores <NUM> are arranged such that the magnets <NUM> respectively attached to the two rotor cores <NUM> have the same polarities. When the output shaft <NUM> has been press-fitted, a part of the output shaft <NUM> protrudes from the rotor core <NUM>. Finally, the cover <NUM> is moved from the side opposite to the side where the output shaft <NUM> protrudes, so as to be fitted to the two rotor cores <NUM>, and then ends of the cover <NUM> on both sides in the output-shaft direction are bent inward in the radial direction, to form bent portions <NUM>, whereby the rotor <NUM> is completed. In arranging the two rotor cores <NUM>, their respective output-shaft-direction opposite-side end surfaces <NUM> are opposed to each other so that the magnet holders <NUM> attached to the respective rotor cores <NUM> do not interfere with each other.

In the magnet holder <NUM>, the output-shaft-direction length of the cutout <NUM> is set to be greater than two times the length of the press-fit pin <NUM>. Therefore, when the come-off prevention protrusion <NUM> of the magnet holder <NUM> is inserted into the insertion groove <NUM> of the rotor core <NUM> from the outer side in the radial direction and then the magnet holder <NUM> is moved in the output-shaft direction, the holder rib <NUM> is prevented from interfering with the core rib <NUM>. Thus, attachment of the magnet holder <NUM> is facilitated.

Next, retention and positioning for the magnets <NUM> will be described. <FIG> is a perspective view showing the rotor core with the magnets attached thereto, and <FIG> is a sectional view along line D-D in <FIG>. As shown in <FIG>, the magnet holders <NUM> are located on both sides in the circumferential direction of each magnet <NUM>, and both ends in the circumferential direction of the radial-direction outer surface of the magnet <NUM> respectively contact with the radial-direction inner surfaces 16a of the arm portions <NUM> of the magnet holders <NUM> on both sides. Thus, the magnet <NUM> is pressed by the radial-direction inner surfaces 16a, whereby the magnet <NUM> is retained in the radial direction. Meanwhile, as shown in <FIG>, a center part of a circumferential-direction one-side surface 13a of the magnet <NUM> contacts with the pressing surface <NUM> of the holder rib <NUM>, and both upper and lower end parts of the circumferential-direction one-side surface 13a are separate from the core ribs <NUM>. A center part of a circumferential-direction opposite-side surface 13b of the magnet <NUM> is separate from the relief surface <NUM> of the holder rib <NUM>, and both upper and lower end parts of the circumferential-direction opposite-side surface 13b contact with the core ribs <NUM>. That is, the magnet <NUM> is retained by the pressing surface <NUM> on one side in the circumferential direction and is retained by the core ribs <NUM> on the opposite side in the circumferential direction. Thus, since the magnet <NUM> is retained on both sides in the circumferential direction, positioning in the circumferential direction is accurately made. In addition, since the core ribs <NUM> and the pressing surface <NUM> are at different positions in the up-down direction, the magnet <NUM> is provided with retention means at positions shifted from each other in the up-down direction on one side and the opposite side in the circumferential direction, and this combination makes a structure in which the upper end part, the center part, and the lower end part are all retained and positioned in the circumferential direction. The dimensional relationship is set such that, when the magnet <NUM> is pressed against the core ribs <NUM>, the relief surface <NUM> does not protrude toward the magnet <NUM> side relative to the core ribs <NUM> and thus the magnet <NUM> is assuredly pressed against the core ribs <NUM>.

Effects obtained by the device configured as described above will be described.

In embodiment <NUM>, the magnet is supported from both sides in the circumferential direction by the pressing surface provided to the holder rib of the magnet holder and the core ribs of the rotor core, whereby fixation and positioning in the circumferential direction can be made. Thus, positioning accuracy for the magnet in the circumferential direction can be improved.

In addition, the relief surface is provided on the side opposite to the pressing surface, whereby the magnet is assuredly pressed against the core ribs. Thus, positioning accuracy for the magnet in the circumferential direction is further improved.

In addition, the cutout is provided to the holder rib of the magnet holder so as to prevent interference with the core rib at the time of insertion into the rotor core. Therefore, the core ribs for positioning can be provided at two locations at both ends in the output-shaft direction, for each magnet. Thus, positioning for the magnet in the circumferential direction relative to the rotor core can be made more accurately.

In addition, the come-off prevention protrusion of the magnet holder is fitted to the lock groove of the rotor core, whereby the magnet holder is prevented from coming off in the radial direction and the non-base-portion side of the magnet holder is prevented from opening in the radial direction.

In addition, in the output-shaft direction, the magnet is retained by the same-polarity magnet attached to the adjacent rotor core and the output-shaft-direction retaining portion of the magnet holder, whereby displacement in the output-shaft direction of the magnet is prevented.

In addition, as compared to a case where the magnet is retained in the output-shaft direction by only a retention force of the bent portions of the cover, a press-fit force of the magnet holder and the rotor core is added for the retention and therefore the magnet can be fixed more strongly in the output-shaft direction.

In addition, since the guide portion <NUM> is provided to the base portion of the magnet holder, the cover can be easily fitted to the rotor core.

In a rotating electric machine, cogging torque, torque ripple, and the like may occur because of positional displacement between the magnet and the rotor core in the circumferential direction and the output-shaft direction, and backlash in the radial direction which occurs when the magnet is inserted. In this case, the performance of the rotating electric machine might be deteriorated. In embodiment <NUM>, as described above, in the circumferential direction, the radial direction, and the output-shaft direction, accurate positioning can be made and the magnet is assuredly fixed. Thus, cogging torque, torque ripple, and the like as described above are reduced, whereby deterioration of the performance of the rotating electric machine due to cogging torque, torque ripple, and the like is suppressed.

Next, embodiment <NUM> will be described with reference to <FIG>. Embodiment <NUM> is different from embodiment <NUM> in that the output-shaft-direction retaining portion of the magnet holder is separated from the base portion and is located on the side opposite to the base portion. The configurations of the rotating electric machine <NUM> and the rotor core <NUM> are the same as those in embodiment <NUM> and therefore description thereof is omitted.

<FIG> is a perspective view of a magnet holder according to embodiment <NUM>. A magnet holder <NUM> is composed of the base portion <NUM> and the arm portion <NUM> as in the magnet holder <NUM> of embodiment <NUM>. The press-fit pin <NUM>, the guide portion <NUM>, the holder rib <NUM>, the cutout <NUM>, and the come-off prevention protrusion <NUM> are also the same as those in embodiment <NUM>.

On the non-base-portion side of the arm portion <NUM>, an output-shaft-direction retaining portion <NUM> extending toward both sides in the circumferential direction is provided. Therefore, the output-shaft-direction retaining portion <NUM> is not provided to the base portion of the magnet holder <NUM>. The shape of the output-shaft-direction retaining portion <NUM> is the same as the shape of the output-shaft-direction retaining portion <NUM> in embodiment <NUM>.

Next, a procedure for assembling the rotor <NUM> in embodiment <NUM> will be described. <FIG> shows a procedure for assembling the rotor in embodiment <NUM>. First, the output shaft <NUM> is press-fitted into the center holes of two rotor cores <NUM>. At this time, their respective output-shaft-direction opposite-side end surfaces <NUM> are opposed to each other as in embodiment <NUM>.

Next, the magnet holder <NUM> is attached to the rotor core <NUM> to which the output shaft <NUM> has been press-fitted at the center. The come-off prevention protrusion <NUM> of the magnet holder <NUM> is inserted into the insertion groove <NUM> of the rotor core <NUM> from the outer side in the radial direction, and then the magnet holder <NUM> is moved in the output-shaft direction so that the press-fit pin <NUM> is press-fitted and fixed into the press-fit hole <NUM> of the rotor core <NUM>. Thereafter, eight magnets <NUM> are inserted for one rotor core <NUM> from the base portion <NUM> sides of the magnet holders <NUM> attached to the rotor core <NUM>. At this time, the push-in surfaces <NUM> of the magnets <NUM> are pushed in simultaneously so as to be flush with the output-shaft-direction one-side end surface <NUM> of the rotor core <NUM>, whereby the magnets <NUM> are inserted into the gap <NUM> between the rotor core <NUM> and the magnet holders <NUM>. Finally, the cover <NUM> is fitted to the two rotor cores <NUM> from the side opposite to the side where the output shaft <NUM> protrudes, and then ends of the cover <NUM> on both sides in the output-shaft direction are bent inward in the radial direction, to form the bent portions <NUM>, whereby the rotor <NUM> is completed. Retention and positioning of the magnets <NUM> are the same as those in embodiment <NUM>.

According to embodiment <NUM>, the same effects as in embodiment <NUM> can be obtained.

In addition, since the output-shaft-direction retaining portion is provided on the non-base-portion side of the arm portion instead of the base portion, it becomes possible to attach the magnet after the output shaft is press-fitted into the rotor core, and therefore positional displacement of the magnet does not occur when the output shaft is press-fitted into the rotor core. Thus, more accurate positioning can be performed. In addition, since the output shaft can be press-fitted into each rotor core one by one, it is not necessary to arrange the two rotor cores with their centers aligned with each other at the time of press-fitting the output shaft. Thus, the equipment configuration is simplified and workability is improved.

Next, embodiment <NUM> will be described with reference to <FIG>. Embodiment <NUM> is different from embodiments <NUM> and <NUM> in that the magnet holder has a plurality of come-off prevention protrusions. The configuration of the rotating electric machine <NUM> is the same as that in embodiment <NUM> and therefore description thereof is omitted.

<FIG> is a perspective view of a magnet holder according to embodiment <NUM>. A magnet holder <NUM> is composed of the base portion <NUM> and the arm portion <NUM> as in the magnet holder <NUM> of embodiment <NUM>. The press-fit pin <NUM>, the output-shaft-direction retaining portion <NUM>, the guide portion <NUM>, and the cutout <NUM> are also the same as those in embodiment <NUM>.

The holder rib <NUM> is provided with two come-off prevention protrusions <NUM> arranged along the output-shaft direction. The shape of each come-off prevention protrusion <NUM> is the same as that in embodiments <NUM> and <NUM>. The holder rib <NUM> is also the same as that in embodiments <NUM> and <NUM> except for the number of the come-off prevention protrusions <NUM>.

<FIG> is a perspective view of a rotor core according to embodiment <NUM>. At both ends in the output-shaft direction of an outer circumferential surface <NUM> of a rotor core <NUM> having substantially an octagonal prism shape, a plurality of core ribs <NUM> protruding outward in the radial direction are provided at predetermined intervals in the circumferential direction. As in embodiment <NUM>, the core rib <NUM> is for positioning the magnet <NUM> by pressing the magnet <NUM>. In embodiment <NUM>, three core ribs <NUM> are provided for each magnet <NUM>. Also in embodiment <NUM>, eight magnets <NUM> are attached to one rotor core <NUM>, and therefore the core ribs <NUM> are provided at twenty-four locations for one rotor core <NUM>.

Between the core ribs <NUM> at two locations for each magnet <NUM>, the insertion grooves <NUM> and the lock grooves <NUM> are provided alternately two by two along the output-shaft direction. Among the two insertion grooves <NUM> and the two lock grooves <NUM>, the insertion groove <NUM> and the lock groove <NUM> on the upper side correspond to the come-off prevention protrusion <NUM> close to the base portion <NUM> in the magnet holder <NUM>. The insertion groove <NUM> and the lock groove <NUM> on the lower side correspond to the come-off prevention protrusion <NUM> far from the base portion <NUM> in the magnet holder <NUM>. As in embodiment <NUM>, the output-shaft-direction length of each of the insertion grooves <NUM> and the lock grooves <NUM> is greater than the output-shaft-direction length of the corresponding come-off prevention protrusion <NUM>. In addition, the distance between the output-shaft-direction one-side end surface <NUM> and each lock groove <NUM> is smaller than the distance between the corresponding come-off prevention protrusion <NUM> and the base portion <NUM> of the magnet holder <NUM>. Thus, when the press-fit pin <NUM> is press-fitted into the press-fit hole <NUM>, each come-off prevention protrusion <NUM> is fitted to the corresponding lock groove <NUM>. The other matters regarding the rotor core <NUM> are the same as the rotor core <NUM> in embodiment <NUM>.

In assembling the rotor <NUM>, the two come-off prevention protrusions <NUM> of the magnet holder <NUM> are inserted into the two insertion grooves <NUM> of the rotor core <NUM> from the outer side in the radial direction, and then the magnet holder <NUM> is moved in the output-shaft direction, whereby the press-fit pin <NUM> is press-fitted and fixed into the press-fit hole <NUM> of the rotor core <NUM>. Insertion of the magnet <NUM>, press-fitting of the output shaft <NUM>, and attachment of the cover <NUM> are the same as those in embodiment <NUM>.

Embodiment <NUM> may be combined with embodiment <NUM>. In this case, the magnet <NUM> is inserted from the base portion side as in embodiment <NUM>.

In addition, since a plurality of come-off prevention protrusions for preventing the magnet holder from coming off in the radial direction are provided, stress applied to each come-off prevention protrusion is dispersed and thus the durability of the magnet holder is improved.

Although the disclosure is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects, and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations to one or more of the embodiments of the disclosure.

It is therefore understood that numerous modifications which have not been exemplified can be devised without departing from the scope of the appended claims.

For example, at least one of the constituent components may be modified, added, or eliminated. At least one of the constituent components mentioned in at least one of the preferred embodiments may be selected and combined with the constituent components mentioned in another preferred embodiment. For example, in embodiments <NUM> to <NUM>, the case of applying the feature according to the present disclosure to a rotating electric machine having a stage-skewed structure has been shown, but the feature according to the present disclosure may be applied to a motor not having a stage-skewed structure.

Claim 1:
A rotor (<NUM>) of rotating electric machine, comprising:
a rotor core (<NUM>,<NUM>) fixed to an output shaft (<NUM>);
a plurality of magnets (<NUM>) arranged on an outer circumference of the rotor core (<NUM>,<NUM>) along a circumferential direction of the output shaft (<NUM>); and
a plurality of magnet holders (<NUM>,<NUM>,<NUM>) each having an arm portion (<NUM>) extending along an axial direction of the output shaft (<NUM>) and a base portion (<NUM>) retaining the arm portion (<NUM>), wherein
the base portion (<NUM>) has a press-fit pin (<NUM>) press-fitted into a press-fit hole (<NUM>) provided at an end surface of the rotor core (<NUM>,<NUM>),
the arm portion (<NUM>) has a holder rib (<NUM>) which protrudes inward in a radial direction of the output shaft (<NUM>) and of which one end surface in the circumferential direction serves as a pressing surface (<NUM>), and a protrusion (<NUM>) inserted into an insertion groove (<NUM>) provided at an outer circumferential surface of the rotor core (<NUM>,<NUM>), and
the magnets (<NUM>) are located between the rotor core (<NUM>,<NUM>) and the magnet holders (<NUM>,<NUM>,<NUM>), one end surface in the circumferential direction of each magnet (<NUM>) contacts with the pressing surface (<NUM>), and another end surface in the circumferential direction of each magnet (<NUM>) contacts with a core rib (<NUM>) protruding from the rotor core (<NUM>,<NUM>).