JP2019103237A - Rotor unit and series of rotor unit - Google Patents

Abstract

To provide a rotor unit that facilitates component dimension control.SOLUTION: A rotor unit 1 used in an electric motor includes a rotor 2, a rotation axis 3 disposed on the inner periphery of the rotor 2, and a cylindrical intermediate member 4 provided between the inner peripheral surface of the rotor 2 and the outer peripheral surface of the rotation axis 3 and connecting the rotor 2 and the rotation axis 3. The rotor 2 and the intermediate member 4 have detent structures 2a and 4e that engage with each other to restrict relative rotation between the rotor 2 and the intermediate member 4, and are integrally molded by insert molding.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotor unit and a series of rotor units used for an electric motor.

  Hitherto, as a method of assembling a rotor constituting an electric motor and a rotary shaft, a method by press-fitting is known.

  For example, Patent Document 1 proposes a method of assembling the rotor 100 and the shaft 300 via a pair of end plates 200 as shown in FIG. Specifically, a pair of end plates 200 are disposed on both sides of the laminated core 101 of the rotor 100, and the inner ring (cylindrical portion) 200a of each end plate 200 is press-fit into the through hole 101a of the laminated core 101, and then each end plate By press-fitting the shaft 300 to the inner ring 200a of 200, the rotor 100 and the shaft 300 are integrally assembled.

JP 2000-184645 A

  By the way, by the method of couple | bonding two components by press fitting, the joint force between components is ensured by setting the magnitude | size of the press-in allowance between both components appropriately. If the press-in margin is too large, the parts can not withstand the press-in load and may be deformed or broken. On the other hand, if the press-in margin is too small, a sufficient bonding force can not be obtained. Therefore, when coupling the rotor and the rotating shaft by press-fitting, the press-in allowance is not properly managed, and if the coupling force is not sufficient, the coupling is performed against the circumferential moment of inertia occurring at the time of rapid acceleration or rapid braking. The forces can not withstand and a relative slip occurs between the rotor and the axis of rotation. Since the occurrence of such slippage leads to a decrease in the accuracy of rotational position control of the electric motor, it is required to manage the press-in allowance appropriately. Further, since the above-mentioned moment of inertia varies depending on the magnitude of the output of the electric motor, there is also a circumstance that the press-in allowance must be set individually according to the output of the electric motor.

  As described above, in the configuration in which the rotor and the rotary shaft are coupled by press fitting, it is not easy to manage the press-in allowance between the parts. However, as in Patent Document 1, the rotor and the rotary shaft (shaft) are coupled. If the end plate is pressed into the laminated core of the rotor (first press), and the shaft is pressed into the end plate (second press), the press-in control There is a problem that (dimension control of parts) becomes severe and the cost becomes high.

  Therefore, an object of the present invention is to provide a rotor unit and a series of rotor units in which dimensional control of parts is easy.

  In order to solve the above problems, the present invention is a rotor unit used for an electric motor, which comprises a rotor, a rotating shaft disposed on the inner periphery of the rotor, and an inner peripheral surface of the rotor and an outer peripheral surface of the rotating shaft. And a cylindrical intermediate member provided between and connecting the rotor and the rotational shaft, wherein the rotor and the intermediate member engage with each other to restrict relative rotation between the rotor and the intermediate member. While having a stop structure, it is characterized by being integrally molded by insert molding.

  As described above, since the rotor and the intermediate member are integrally formed by insert molding, management of the press-in allowance between the rotor and the intermediate member becomes unnecessary as compared with the case where these are assembled by press-fitting. , Easy to manage the dimensions of parts. For this reason, the cost required for dimensional control can be reduced, and cost reduction can be achieved. In addition, the rotor and the intermediate member have a detent structure that engages with each other to restrict relative rotation between the rotor and the intermediate member, so that rotation by press-in which requires adjustment of the press-in margin is required. Compared with the stopping means, circumferential slippage between the rotor and the intermediate member can be prevented easily and reliably, and the reliability is improved.

  The rotation preventing structure includes a convex engaging portion formed on one of the inner peripheral surface of the rotor and the outer peripheral surface of the intermediate member, and a concave engaging portion formed on the other so as to engage with the convex engaging portion. It can be configured.

  In addition, it is desirable that a detent structure that engages with each other to restrict rotation is also provided between the inner peripheral surface of the intermediate member and the outer peripheral surface of the rotation shaft. This makes it possible to reliably prevent circumferential slippage between the intermediate member and the rotating shaft, thereby further improving the reliability. The anti-rotation structure is, for example, a convex engagement portion formed on one of the inner peripheral surface of the intermediate member and the outer peripheral surface of the rotation shaft, and a concave engagement formed on the other so as to engage the convex engagement portion. It can consist of parts.

  In addition, a pair of protrusions that contact with both axial end surfaces of the rotor may be integrally provided at both axial end portions of the intermediate member. Thereby, axial movement of the rotor with respect to the intermediate member can be restricted. In addition, it is not necessary to separately provide a dedicated member for restricting the axial movement of the rotor, so that the number of parts can be reduced and the cost can be reduced. In addition, since such projections are insert-molded on the rotor together with the intermediate member, even if there is variation in the axial length of the rotor, the projections can be separated from the respective rotors. It is possible to mold without contact and to positionally regulate the rotor with high accuracy. As a result, it is possible to reliably prevent the fluctuation of the magnetic circuit that occurs when the positional relationship between the stator and the rotor deviates in the axial direction, and it is possible to provide a highly reliable electric motor with stable performance.

  Also, the intermediate member and the rotary shaft may be integrally molded by insert molding. In that case, it is not necessary to control the press-fit allowance between the rotating shaft and the intermediate member, so the dimensional control of the parts is further facilitated.

  The rotor generally has a surface magnet type in which a magnet is attached to the surface of the rotor core, and an embedded magnet type in which a magnet is embedded inside the rotor core, but the rotor applied to the present invention is a surface magnet type Is preferred. In the case of the surface magnet type, since the intermediate member can be insert-molded to the rotor core before the magnet is attached, the magnet is not affected by the heat during insert molding. Therefore, by adopting the surface magnet type rotor, it is possible to avoid the possibility that the magnet is thermally demagnetized due to the influence of heat at the time of insert molding and the performance is degraded, and the performance of the magnet can be maintained favorably. .

  Further, by making the intermediate member made of resin, the weight of the rotor unit can be reduced as compared to the case where the intermediate member is made of metal or the like.

  Further, the present invention is a series of rotor units used for an electric motor, which is provided between a rotor, a rotary shaft arranged on the inner periphery of the rotor, and an inner peripheral surface of the rotor and an outer peripheral surface of the rotary shaft. Is provided with a plurality of types of rotor units each including a cylindrical intermediate member connecting the rotor and the rotation shaft, each time the outer diameter of the rotor is different, and the rotor and the intermediate members in each type of rotor unit are engaged with each other And has a detent structure for restricting relative rotation between the rotor and the intermediate member, and is integrally molded by insert molding, and all the intermediate members in each type of rotor unit have the same inner diameter. It is characterized by being.

  Thus, as the rotor and the intermediate member are integrally formed by insert molding, similarly to the above, dimensional control of the rotor and the intermediate member becomes easier as compared with the case where they are assembled by press fitting. Cost reduction can be achieved. In addition, since the intermediate members in each type of rotor unit are all formed to have the same inner diameter, it is possible to insert and assemble a rotary shaft with the same outer diameter into the intermediate member. That is, even when the rotor units are developed in series using rotors having different outer diameters, the common (one type) rotation shaft can be used by forming the inner diameters of all the intermediate members to the same size. Therefore, it is not necessary to align rotation axes different in outer diameter for each type of rotor unit, and cost can be reduced.

  According to the present invention, dimensional control of parts of the rotor unit is facilitated, and cost reduction can be achieved.

It is a perspective view of a rotor unit concerning an embodiment of the present invention. It is a longitudinal cross-sectional view of a rotor unit shown in FIG. It is a disassembled perspective view of a rotor unit shown in FIG. It is an expanded sectional view which expands and shows a caulking part. It is a longitudinal cross-sectional view which shows one structural example of the rotor unit among series of the rotor unit which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the structural example of another rotor unit. It is a figure which shows the assembly | attachment structure of the conventional rotor and rotating shaft.

  Hereinafter, the present invention will be described based on the attached drawings. In each drawing for explaining the present invention, components such as members or components having the same function or shape are denoted by the same reference numerals as long as discrimination is possible, and then the explanation thereof will be described. I omit it.

  FIG. 1 is a perspective view of a rotor unit for an electric motor according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the rotor unit shown in FIG. 3 is an exploded perspective view of the rotor unit shown in FIG. 1, and FIG. 4 is an enlarged cross-sectional view showing a portion surrounded by a two-dot chain line in FIG.

  As shown in FIGS. 1 to 3, the rotor unit 1 according to the present embodiment is configured of a rotor 2, a rotating shaft 3, and an intermediate member 4.

  The rotor 2 is disposed to face the stator constituting the electric motor when the rotor unit 1 is applied to the electric motor, and the magnetic flux generated between the coil and the stator when power is supplied to the coil. It is a member that rotates by action. Specifically, the rotor 2 is configured by an annular rotor core 5 formed of a plurality of steel plates (for example, electromagnetic steel plates etc.) axially stacked, and a plurality of magnets 6 attached to the outer peripheral surface of the rotor core 5 There is. On the outer peripheral surface of the rotor core 5, a plurality of convex claws 5a engaged with both end surfaces in the circumferential direction of each magnet 6 are provided. By inserting the magnet 6 in the axial direction between the pair of claws 5a, the magnet 6 is held by the pair of claws 5a so as not to be separated in the outer diameter direction. However, since the axial movement of the magnet 6 can not be restricted in the claw portion 5 a, an adhesive is applied to the back surface of the magnet 6 and the magnet 6 is adhered to the outer peripheral surface of the rotor core 5. On the other hand, it does not leave in the axial direction. Further, instead of bonding the magnets 6 to the rotor core 5, cover members are provided to cover the outer circumferences and both axial end faces of the respective magnets 6, and the cover members prevent the magnets 6 from coming off the rotor core 5. You may

  The rotation shaft 3 is formed of a metallic solid body and disposed on the inner periphery of the rotor 2. The intermediate member 4 is a cylindrical member made of resin provided between the inner peripheral surface of the rotor 2 and the outer peripheral surface of the rotary shaft 3 to connect the rotor 2 and the rotary shaft 3. Specifically, the intermediate member 4 includes a small cylindrical portion 4a, a large cylindrical portion 4b disposed on the outer peripheral side of the small cylindrical portion 4a and having an outer diameter and an inner diameter larger than the small cylindrical portion 4a, a small cylindrical portion 4a and a large cylindrical portion And an annular portion 4c extending in the radial direction at the axially intermediate portion with 4b to connect them.

  As shown in FIG. 3, a plurality of convex engaging portions 4d extending in the axial direction are provided on the inner peripheral surface of the small cylindrical portion 4a. On the other hand, on the outer peripheral surface of the rotary shaft 3, a plurality of concave engaging portions 3a extending in the axial direction are provided so as to correspond to the plurality of convex engaging portions 4d provided in the small cylindrical portion 4a. The concave engaging portion 3a and the convex engaging portion 4d are engaged with each other in a state where the rotary shaft 3 is inserted into the small cylindrical portion 4a and assembled as shown in FIG. The circumferential rotation between the rotation shaft 3 and the intermediate member 4 is restricted. That is, the concave engaging portion 3a and the convex engaging portion 4d engage with each other to restrict the rotation between the outer peripheral surface of the rotary shaft 3 and the inner peripheral surface of the intermediate member 4 (small cylindrical portion 4a). It functions as a detent structure.

  Further, at an axially intermediate portion of the rotary shaft 3, a flange portion 3b is provided which protrudes in the outer diameter direction from the outer peripheral surface. As shown in FIG. 2, when the rotary shaft 3 is inserted into the small cylindrical portion 4a, the collar portion 3b abuts on the axial end of the small cylindrical portion 4a to position the rotary shaft 3 with respect to the small cylindrical portion 4a. do. Further, the caulking portion 3c provided on the rotating shaft 3 is in contact with the end on the opposite side to the end of the small cylindrical portion 4a, so that the axial direction of the intermediate member 4 with respect to the rotating shaft 3 It regulates movement.

  As shown in FIG. 3, the crimped portion 3 c is provided at an end (an end opposite to the side of the collar portion 3 b) of the axial region A in which the concave engagement portion 3 a is provided. Moreover, the caulking part 3c is in the state shown by the solid line in FIG. 4 so as not to prevent the insertion of the rotary shaft 3 into the intermediate member 4 before caulking. That is, the caulking portion 3c before caulking is formed to be flush with the outer peripheral surface of the axial region A provided with the concave engaging portion 3a, or not to protrude in the outer diameter direction from the outer peripheral surface . Moreover, the groove part 3e is formed over the circumferential direction at the edge part in which the crimping part 3c was provided (refer FIG. 4). With the rotary shaft 3 inserted into the small cylindrical portion 4a of the intermediate member 4 and the collar portion 3b abutted against the end of the small cylindrical portion 4a to position the rotary shaft 3, a hammer or the like is driven into the groove 3e, By bending the crimped portion 3c in the outer diameter direction as shown by the dotted line in FIG. 4, the axial movement of the intermediate member 4 is restricted by the crimped portion 3c.

  Further, as shown in FIG. 3, a plurality of concave engaging portions 4e extending in the axial direction are provided on the outer peripheral surface of the large cylindrical portion 4b. On the other hand, on the inner peripheral surface of the rotor 2 (the rotor core 5), a plurality of convex engaging portions 2a extending in the axial direction are formed to correspond to the plurality of concave engaging portions 4e provided in the large cylindrical portion 4b. There is. The convex engaging portion 2 a and the concave engaging portion 4 e engage with each other to restrict circumferential rotation between the rotor 2 and the intermediate member 4. That is, the convex engaging portion 2a and the concave engaging portion 4e are mutually engaged to restrict rotation between the inner peripheral surface of the rotor 2 and the outer peripheral surface of the intermediate member 4 (large cylindrical portion 4b). It functions as a stop structure.

  Further, a pair of protruding portions 4 f protruding in the outer diameter direction is provided over the entire circumference at both axial direction end portions of the large cylindrical portion 4 b. The pair of protrusions 4 f restricts axial movement of the rotor 2 with respect to the intermediate member 4 by contacting both axial end faces of the rotor 2 (the rotor core 5) (see FIG. 2). Prevents axial separation.

  Here, in the rotor unit according to the present embodiment configured as described above, the connection between the rotary shaft 3 and the intermediate member 4 can be made by either the clearance of the rotary shaft 3 with respect to the small cylindrical portion 4a or press fitting. However, it is desirable that the coaxiality between the rotary shaft 3 and the rotor 2 be a press-in that can be assembled with higher accuracy. Further, in the transmission of the rotational torque between the rotary shaft 3 and the intermediate member 4, since the concave engagement portion 3 a and the convex engagement portion 4 d receive torque, the press fit margin in the case of the press fit is the same as that of the electric motor. There is no need to set individually according to the output etc. On the other hand, the rotor 2 and the intermediate member 4 are coupled not by press-fitting but by integral molding by insert molding.

  As described above, since the rotor 2 and the intermediate member 4 are integrally formed by insert molding, they do not have to be connected by press-fitting, so that a press-in allowance (for example, several tens of) between the rotor 2 and the intermediate member 4 Management of micron) is not required. Moreover, compared with the double press-fit structure as described in the above-mentioned patent documents 1, a press-fit location can be reduced and a press-fit location can be made only to one place between rotating shaft 3 and middle member 4 And, the specification of the press-fit allowance can be unified into one. As a result, dimensional control of parts constituting the rotor unit becomes easy, and manufacturing costs can be reduced.

  Further, between the rotor 2 and the intermediate member 4 and between the rotary shaft 3 and the intermediate member 4, a rotation preventing structure is provided by the engagement of the convex engaging portion and the concave engaging portion, As compared with the rotation prevention means by press-in which requires adjustment of the press-in allowance, it is possible to prevent the circumferential slippage between the respective members easily and reliably. Further, by adopting such a rotation stopping structure, in the configuration in which the rotational position of the rotor is detected to control the electric motor, in particular, the accuracy of the rotational position control is improved, thereby improving the reliability.

  In addition, the concavo-convex relationship between the convex engaging portion and the concave engaging portion in the above embodiment may be reversed. Moreover, such a rotation prevention structure is, for example, the inner peripheral surface of the rotor 2 and the outer peripheral surface of the intermediate member 4 or the rotation other than the one formed by the convex engaging portion and the concave engaging portion engaged with each other. The outer peripheral surface of the shaft 3 and the inner peripheral surface of the intermediate member 4 may be prevented from rotating by forming them into non-perfect circular shapes such as polygonal shapes.

  Further, in the above embodiment, the pair of projections 4 f for restricting the axial movement of the rotor 2 is insert-molded on the rotor 2 together with the intermediate member 4 so that it is higher than in the case of using the retaining ring. Position control can be performed with accuracy. That is, in the case of the retaining ring, in consideration of the variation in the axial length of the rotor core, a groove for attaching the intermediate member is provided in advance so that the retaining ring can be attached even when the axial length of the rotor core is maximum. Although it must be formed, if the axial length of the rotor core is short, an axial gap may occur between the retaining ring and the rotor core, and the rotor core may be axially displaced.

  On the other hand, even if there is a variation in the axial length of the rotor 2 (the rotor core 5), the projection 4f which is insert-molded together with the intermediate member 4 does not have a gap from each rotor 2 It is possible to make contact, and position control of the rotor 2 can be performed with high accuracy as compared with position control using a retaining ring. As a result, it is possible to reliably prevent the fluctuation of the magnetic circuit that occurs when the positional relationship between the stator and the rotor deviates in the axial direction, and it is possible to provide an electric motor with stable performance and high reliability. Further, by integrally molding the pair of projections 4f with the intermediate member 4, it is not necessary to separately provide a dedicated member such as a snap ring, and the number of parts can be reduced, so that cost reduction can be achieved. Become.

  By the way, the rotor generally has a type called a surface magnet type (SPM: Surface Permanent Magnet) in which a magnet is attached to the outer peripheral surface (surface) of the rotor core as in the above embodiment, and Separately, there are two types of types, called an interior permanent magnet (IPM) type in which a magnet is embedded inside the rotor core. The configuration of the present invention is applicable not only to the surface magnet type (SPM) but also to the embedded magnet type (IPM).

  However, in the case of the embedded magnet type (IPM), since it is necessary to perform insert molding with the intermediate member in a state in which the magnet is embedded in the rotor core, it is conceivable that the magnet is somewhat affected by heat during insert molding. Therefore, depending on the type of magnet, the heat during insert molding may cause heat demagnetization, which may reduce the magnetic force, and care should be taken.

  On the other hand, in the case of the surface magnet type (SPM), since the intermediate member can be insert-molded to the rotor core before the magnet is attached, the magnet is not affected by the heat at the time of insert molding. Therefore, it is preferable to use a surface magnet type (SPM) rotor in order to avoid thermal demagnetization and maintain good performance of the magnet.

  Moreover, as a material of the intermediate member 4, thermoplastic synthetic resins called so-called engineering plastics such as PBT (polybutylene terephthalate), and thermoplastic synthetic resins such as PPS (polyphenylene sulfide) and PEEK (polyether ether ketone) Or the thermoplastic synthetic resin in which fibrous reinforcements, such as GF (glass fiber) and CF (carbon fiber), were contained is mentioned. Although it is possible to use metal materials other than resin etc. as a material of intermediate member 4, weight reduction can be attained by making intermediate member 4 into resin. In the case where the intermediate member 4 is made of resin, application to a small output electric motor is desirable from the viewpoint of the strength (durability) to the rotational torque of the intermediate member 4.

  Subsequently, a series of rotor units according to the present invention will be described.

  FIG.5 and FIG.6 is a longitudinal cross-sectional view which shows the structural example of the one part rotor unit among series of the rotor unit which concerns on embodiment of this invention.

  The rotor unit 1A shown in FIG. 5 and the rotor unit 1B shown in FIG. 6 use the rotors 2 having different outer diameters and inner diameters. The basic configuration of each of the rotor units 1A and 1B is the same as that of the rotor unit according to the above-described embodiment shown in FIGS. In this case, the rotor unit 1B shown in FIG. 6 uses the rotor 2 with an outer diameter and an inner diameter larger than the rotor unit 1A shown in FIG. 5 (B2> B1, C2> C1). Moreover, in connection with this, in the rotor unit 1B shown in FIG. 6, the intermediate member 4 with a larger outer diameter than the rotor unit 1A shown in FIG. 5 is used (D2> D1). In this case, in the rotor unit 1B shown in FIG. 6, the outer diameter of the intermediate member 4 is formed large by forming the annular portion 4c of the intermediate member 4 large in the radial direction.

  As described above, in each of the rotor units 1A and 1B shown in FIGS. 5 and 6, the outer diameter of the intermediate member 4 is made different according to the size of the rotor 2 in the radial direction. The inner diameter of the intermediate member 4 in the units 1A and 1B is set to the same size (E1 = E2).

  As described above, in the series of rotor units according to the present embodiment, the inner diameter of the intermediate member 4 of each of the rotor units 1A and 1B is set to the same size. It is possible to insert and assemble the rotating shaft 3. That is, even when the rotor unit is developed in series using rotors having different outer diameters and inner diameters, the common (one type) rotary shaft can be obtained by forming the inner diameters of all the intermediate members in the same size. It can be used. As a result, it is not necessary to align the rotation axes different in outer diameter for each type of rotor unit, and series development can be performed using one type of rotation axis, so cost reduction can be achieved.

  Also, in the series using rotors of different sizes, the magnitudes of the rotational torque and the moment of inertia generated between the rotor and the intermediate member and between the rotary shaft and the intermediate member differ due to differences in the rotor output. By providing a detent mechanism that regulates rotation by engaging each other with each other, even with rotor units having different outputs, slippage does not occur using a similar detent structure. It is possible to correspond. That is, in the case of restricting the rotation only by the coupling force by the press-in, it is necessary to set the press-in allowance between the parts individually according to the size of the rotational torque and the moment of inertia. The press-in allowance does not have to be set individually, and can widely correspond to rotational torques and inertia moments of various sizes.

  Further, in each of the rotor units 1A and 1B shown in FIGS. 5 and 6, the rotor and the intermediate member are integrally molded by insert molding, similarly to the rotor unit according to the embodiment shown in FIGS. There is. Therefore, in each of the rotor units 1A and 1B as well, the press-fit locations are reduced, and dimensional management of components (management of press-fit allowance) becomes easy, so cost reduction can be achieved.

  As mentioned above, although the rotor unit concerning the embodiment of the present invention and its series were explained, the present invention is not limited to the above-mentioned embodiment. In the above embodiment, the rotary shaft is assembled to the intermediate member, but the rotary shaft may be integrally formed by insert molding in addition to the rotor and the intermediate member. In that case, it is not necessary to control the press-fit allowance between the rotating shaft and the intermediate member, so the dimensional control of the parts becomes even easier. Further, in the above embodiment, the engagement portion between the rotation shaft 3 and the intermediate member 4 (concave engagement portion 3a, convex engagement portion 4d), and the engagement portion between the intermediate member 4 and the rotor 2 (concave engagement portion Although 4e and the convex engaging part 2a) are provided in three places, respectively, the place where such an engaging part is provided may be one place or plural places.

DESCRIPTION OF SYMBOLS 1 rotor unit 2 rotor 2a convex engagement part 3 rotating shaft 3a concave engagement part 4 intermediate member 4d convex engagement part 4e concave engagement part 4f projection part 5 rotor core 6 magnet

Claims (8)

A rotor unit used for an electric motor,
A tubular intermediate which is provided between a rotor, a rotary shaft arranged on the inner periphery of the rotor, and an inner peripheral surface of the rotor and an outer peripheral surface of the rotary shaft to connect the rotor and the rotary shaft Equipped with
The rotor and the intermediate member have a detent structure which engages with each other to restrict relative rotation between the rotor and the intermediate member, and is integrally molded by insert molding. And a rotor unit.   The anti-rotation structure includes a convex engagement portion formed on one of the inner peripheral surface of the rotor and the outer peripheral surface of the intermediate member, and a concave engagement formed on the other so as to engage the convex engagement portion. The rotor unit according to claim 1, comprising: There is provided an anti-rotation structure which engages with each other between the inner peripheral surface of the intermediate member and the outer peripheral surface of the rotary shaft to restrict rotation.
The anti-rotation structure includes a convex engaging portion formed on one of the inner peripheral surface of the intermediate member and the outer peripheral surface of the rotating shaft, and a concave formed on the other so as to engage the convex engaging portion. The rotor unit according to claim 1, wherein the rotor unit comprises an engaging portion.   The projection part which contacts the axial direction both end surfaces of the rotor in the axial direction both ends of the intermediate member, and which restricts the axial direction movement of the rotor to the intermediate member is provided in one. The rotor unit as described in a term.   The rotor unit according to any one of claims 1 to 4, wherein the intermediate member and the rotary shaft are integrally molded by insert molding.   The rotor according to any one of claims 1 to 5, wherein the rotor is a surface magnet type rotor having a rotor core formed of a plurality of steel plates stacked in the axial direction and a plurality of magnets attached to the outer peripheral surface of the rotor core. The rotor unit as described in.   The rotor unit according to any one of claims 1 to 6, wherein the intermediate member is made of resin. A series of rotor units used for electric motors,
A cylindrical intermediate member provided between a rotor, a rotary shaft arranged on the inner periphery of the rotor, and an inner peripheral surface of the rotor and an outer peripheral surface of the rotary shaft to connect the rotor and the rotary shaft And a plurality of types of rotor units each having a different member for each different outer diameter of the rotor,
The rotor and the intermediate member in each type of the rotor unit have a detent structure which engages with each other to restrict relative rotation between the rotor and the intermediate member, and is integrally formed by insert molding. Molded,
A series of rotor units characterized in that the intermediate members in the rotor units of each type are all formed to have the same inner diameter.

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