An inner-rotor motor includes a separating member, a stator and a rotor. The separating member is made of an insulating material and includes a first separating part and a second separating part. The separating member includes at least one engaging portion extending along an axial direction of the inner-rotor motor. The stator includes an iron core received in a space jointly defined by the first and second separating parts. The iron core includes at least one engaging groove arranged on an outer surface thereof and extending along the axial direction of the inner-rotor motor. The at least one engaging portion is received in the at least one engaging groove. The rotor is rotatably coupled to the separating member. As such, a convenient assembly and reduced volume of the inner-rotor motor are provided.

CROSS REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of Taiwan application serial No. 104114484, filed on May 6, 2015, and the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an inner-rotor motor and, more particularly, to an inner-rotor motor having a separating member.

2. Description of the Related Art

A conventional inner-rotor motor includes an outer metallic housing and several components arranged in the metallic housing, such as a stator iron core, a driving circuit and a bearing. In this arrangement, electricity may be conducted between the metallic housing and the components, leading to the generation of a leakage current in the conventional inner-rotor motor.

To overcome this problem, another conventional inner-rotor motor9is provided as shown inFIG. 1. The inner-rotor motor9includes a stator91and a separating member92. The separating member92is made of a non-conductive, plastic material and is used to receive the stator91. The separating member92may be coupled with a metallic housing93for insulating purposes, to prevent the generation of a leakage current between the stator91and the metallic housing93. Such a conventional inner-rotor motor9can be seen in Taiwan Patent No. M297577.

The separating member92is in the form of a cylindrical wall. Therefore, the stator91must be fastened with the separating member92to prevent relative rotation therebetween. The stator91includes a first screwing portion911, and the separating member92includes a second screwing portion921aligned with the first screwing portion911. In this arrangement, the separating member92can be fastened to the stator91using a screw “S.” However, since the separating member92is coupled to the stator91by fastening, the assembly of the inner-rotor motor9is inconvenient. Additionally, a single pair of the first and second screwing portions911and912may not be sufficient to provide a secure engagement between the separating member92and the stator91. Thus, two or more pairs of the first and second screwing portions911and912are needed to fasten the separating member92to the stator91in a secure manner via the use of multiple screws “S.” Disadvantageously, the assembly of the inner-rotor motor9is even more inconvenient.

Furthermore, the separating member92is fastened to the metallic housing93using the same screw “S.” Since the separating member92is in the form of the cylindrical wall, the screw “S” must be arranged outwards of an outer surface of the separating member92to fasten the separating member92and the metallic housing93to each other. A radial length of the inner-rotor9motor is thus increased by the screw “S” arranged outwards of the outer surface of the separating member92. Namely, when the separating member92is in the form of the cylindrical wall, arrangement of the screw “S” will certainly increase the volume of the inner-rotor motor9.

Moreover, since a circuit or a coil inside the stator91has to be electrically connected to power or an actuator outside the inner-rotor motor9via a conducting wire, it is necessary to maintain a space between the separating member92and the metallic housing93for the conducting wire to extend through. However, arrangement of the space between the separating member92and the metallic housing93may further increase the volume of the inner-rotor motor9.

In light of the above, it is necessary to improve the inner-rotor motor9to solve the problems of inconvenient assembly and large volume occupation.

SUMMARY OF THE INVENTION

It is therefore the objective of this invention to provide an inner-rotor motor that includes a separating member having at least one first engaging portion, as well as an iron core having at least one engaging groove arranged on an outer surface of the iron core for receiving the protrusion. Thus, convenient assembly of the inner-rotor motor is provided.

The present invention provides an inner-rotor motor including a separating member, a stator and a rotor. The separating member is made of an insulating material and includes a first separating part and a second separating part. The separating member includes at least one engaging portion extending along an axial direction of the inner-rotor motor. The stator includes an iron core received in a space jointly defined by the first and second separating parts. The iron core includes at least one engaging groove arranged on an outer surface thereof and extending along the axial direction of the inner-rotor motor. The at least one engaging portion is received in the at least one engaging groove. The rotor is rotatably coupled to the separating member.

In a form shown, the rotor includes a shaft arranged at a center of the iron core. Each of the at least one engaging groove extends towards the shaft. The at least one engaging portion protrudes inwards towards the iron core.

In the form shown, the first separating part includes a base plate extending along a radial direction of the inner-rotor motor. A lateral wall is connected to the base plate and extends along the axial direction of the inner-rotor motor towards the second separating part, and the at least one engaging portion includes at least one first engaging portion arranged on the lateral wall of the first separating part.

In the form shown, the second separating part includes a base plate extending along the radial direction of the inner-rotor motor. A lateral wall is connected to the base plate and extends along the axial direction of the inner-rotor motor towards the first separating part. The at least one engaging portion further includes at least one second engaging portion arranged on the lateral wall of the second separating part and extending along the axial direction of the inner-rotor motor.

In the form shown, a quantity of the at least one first engaging portion is larger than or equal to a quantity of the at least one second engaging portion. Each of the at least one second engaging portion is aligned with a respective one of the at least one first engaging portion.

In the form shown, the at least one first engaging portion includes a plurality of first engaging portions. The at least one second engaging portion includes a plurality of second engaging portions. Each of the plurality of second engaging portions is aligned with a respective one of the plurality of first engaging portions along the axial direction of the inner-rotor motor.

In the form shown, the at least one first engaging portion includes a plurality of first engaging portions. The at least one second engaging portion also includes a plurality of second engaging portions aligned with the plurality of first engaging portions along the axial direction of the inner-rotor motor. The first separating part includes a first channel arranged at one of the plurality of first engaging portions, and the second separating part includes a second channel arranged at one of the plurality of second engaging portions.

In the form shown, the first separating part includes a first coupling portion arranged in the first channel, and the second separating part includes a second coupling portion arranged in the second channel and coupled to the first coupling portion.

In the form shown, the first coupling portion is in a form of a fastener. The second coupling portion is in a form of a fastening groove. The first and second coupling portions are coupled to each other via the fastener and the fastening groove.

In the form shown, the inner-rotor motor further includes a metallic housing receiving the separating member.

In the form shown, a screwing member extends through the metallic housing, the first channel and the second channel to fasten the separating member in the metallic housing.

In the form shown, the metallic housing includes a body in a form of a hollow cylinder having two openings formed at two opposite ends thereof. The body encloses the first and second separating parts of the separating member. Two lids are arranged respectively at the two openings of the body, and each of the two lids includes a fastening hole arranged at an outer area adjacent to an outer edge thereof. The fastening hole is aligned with the one of the plurality of first engaging portions and the one of the plurality of second engaging portions. The screwing member extends through the fastening holes of the two lids to fix the separating member between the two lids.

In a further form shown, the separating member further includes a through-hole arranged at the first separating part or the second separating part. A wire extends out of the separating member via the through-hole, and the wire is received in the first channel or the second channel.

In the form shown, the inner-rotor motor further includes a circuit board received in the space defined by the first and second separating parts together. One end of the wire is electrically connected to the circuit board, and another end of the wire extends along the first channel or the second channel.

In the form shown, a coil is arranged around an outer periphery of the iron core of the stator. One end of the wire is electrically connected to the coil, and another end of the wire extends along the first channel or the second channel.

In the form shown, the first channel is in a form of a receiving groove formed on an outer surface of the lateral wall of the first separating part, and the second channel is also in a form of a receiving groove formed on an outer surface of the lateral wall of the second separating part. Alternatively, the first channel is in a form of an extending hole extending through two opposite sides of the one of the plurality of first engaging portions along the axial direction of the inner-rotor motor, and the second channel is also in a form of another extending hole extending through two opposite sides of the one of the plurality of second engaging portions along the axial direction of the inner-rotor motor.

According to the above, the at least one engaging portion and the at least one engaging groove extend along the axial direction of the inner-rotor motor. The at least one engaging portion is received in the at least one engaging groove for fixing the iron core relative to the separating member. Thus, a convenient assembly of the motor is provided.

DETAILED DESCRIPTION OF THE INVENTION

Please refer toFIGS. 2 and 3, an inner-rotor motor according to a first embodiment of the present invention includes a separating member1, a stator2and a rotor3. The stator2is received in the separating member1, and the rotor3is rotatably coupled to the separating member1.

The separating member1may be made of an insulating material such as plastic. Specifically, the separating member1may include a first separating part11and a second separating part12which can be coupled to each other to form the separating member1. The first separating part11includes a base plate B1extending along a radial direction of the inner-rotor motor. A lateral wall B2is connected to and extends from an outer edge of the base plate B1toward the second separating part12along an axial direction of the inner-rotor motor, such that the first separating part11is in the form shown inFIG. 3. The first and second separating parts11and12are coupled to each other via the lateral wall B2of the first separating part11along the axial direction of the inner-rotor motor. Thus, the first and second separating parts11and12jointly define a space for receiving the stator2. At least one first engaging portion13is arranged on the lateral wall B2of the first separating part11and extends along the axial direction of the inner-rotor motor.

The stator2includes an iron core21received in the separating member1. Namely, the iron core21is received in the space defined by the first and second separating parts11and12, such that the iron core21can be completely enclosed by said separating parts11and12. At least one engaging groove211is arranged on an outer surface of the iron core21and extends along the axial direction of the inner-rotor motor for receiving the at least one first engaging portion13of the separating member1.

More specifically, the at least one engaging groove211is formed on the outer surface of the iron core21, and the at least one first engaging portion13protrudes from an inner surface of the lateral wall B2of the first separating part11toward the iron core21. The at least one first engaging portion13protrudes toward the iron core21and structurally corresponds to the shape of the at least one groove211, to be received in the at least one engaging groove211. Additionally, the amount of the at least one engaging groove211may be equal to or larger than the amount of the at least one first engaging portion13. Preferably, the amount of the at least one engaging groove211is equal to the amount of the at least one first engaging portion13, such that each of the at least one first engaging portion13can be received in a respective one of the at least one engaging groove211.

The rotor3is rotatably coupled to the separating member1and includes a shaft31and a permanent magnet assembly32. The shaft31is arranged at a center of the permanent magnet assembly32received in the space defined by the first and second separating parts11and12. Specifically, the shaft31is rotatably coupled to the first separating part11or the second separating part12, and the permanent magnet assembly32may be coupled to an outer surface of the shaft31. In this arrangement, a gap is formed between the permanent magnet assembly32and the iron core21of the stator2, thus forming the inner-rotor motor according to the first embodiment of the present invention. The shaft31extends through a center of the iron core21and may extend out of the separating member1through the first separating part11or the second separating part12. It is noted that the at least one groove211of the iron core21extends towards the shaft31. Specifically, a reference plane “R” is defined to pass each engaging groove211and the shaft31. Based on this, the part of the engaging groove to the left of the reference plane “R” is symmetric to the part of the engaging groove211to the right of the reference plane “R.”

When the inner-rotor motor according to the first embodiment of the present invention is in use, an electromagnetic effect is generated between the iron core21and the permanent magnet assembly32when a coil wound around the iron core21is electrified. Thus, the shaft31is driven to rotate relative to the iron core21. The operational principles and detailed structures of the stator2and the rotor3are not discussed herein, since it can be readily appreciated by ordinarily skilled persons in the art.

According to the arrangement described above, when the inner-rotor motor according to the first embodiment of the present invention is assembled, it is simply required to place the iron core21in the separating member1, and each first engaging portion13of the separating member1is therefore received in a corresponding engaging groove211of the iron core21, thus fixing the iron core21relative to the separating member1. Therefore, it prevents the iron core21from rotating relative to the separating member1. In addition, the at least one engaging groove211may include a plurality of engaging grooves211, and the at least one first engaging portion13may include a plurality of first engaging portions13each received in a respective one of the plurality of engaging grooves211in order to enhance the engagement between the separating member1and the iron core21.

Likewise, the second separating part12also includes a base plate B1extending along the radial direction of the inner-rotor motor. In addition, a lateral wall B2is connected to and extends from the base plate B1towards the first separating part11along the axial direction of the inner-rotor motor, such that the second separating part12is in the form shown inFIG. 3. Furthermore, the separating member1further includes at least one second engaging portion13′ arranged at the lateral wall B2of the second separating part12and extending along the axial direction of the inner-rotor motor. The at least one first engaging portion13of the first separating part11is aligned with the at least one second engaging portion13′ of the second separating part12. Due to the arrangement of the at least one second engaging portion13′ on the lateral wall B2of the second separating part12, the second separating part12can be coupled with other components of the inner-rotor motor via the second engaging portion13′, such as a motor base.

Specifically, the amount of the at least one first engaging portion13may be larger than or equal to that of the second engaging portion13′. Preferably, the amount of the at least one first engaging portion13is equal to the amount of the at least one second engaging portion13′, such that each of the at least one second engaging portion13′ is aligned with a respective one of the at least one first engaging portion13along the radial direction of the inner-rotor motor. Namely, the first separating part11may include a plurality of first engaging portions13, and the second separating part12may include a plurality of second engaging portions13′ each aligned with a respective one of the plurality of first engaging portions13along the axial direction of the inner-rotor motor.

Moreover, the at least one first engaging portion13of the first separating part11may include a first channel13a. The first channel13amay be in the form of a receiving groove. Namely, the first channel13ais formed on the outer surface of the lateral wall B2. The at least one second engaging portion13′ of the second separating part12may also include a second channel13a′ formed on the outer surface of the lateral wall B2. When the at least one first engaging portion13includes a plurality of first engaging portions13, one of the plurality of first engaging portions13may include the channel13awhile the others do not. In another case, in the plurality of first engaging portions13, there may be more than one first engaging portion13each including the channel13a. In a further case, each of the plurality of first engaging portions13may include the channel13a. Likewise, the at least one second engaging portion13′ of the second separating part12may have a similar arrangement as the at least one first engaging portion13of the first separating part11. Since the first channel13ais in the form of the receiving groove having an opening, other structures or components may be received in the channel13avia the opening.

Since the at least one second engaging portion13′ is aligned with the at least one first engaging portion13along the axial direction of the inner-rotor motor, the first and second separating parts11and12may respectively include the first and second channels13aand13a′ aligned with each other along the axial direction of the inner-rotor motor. In such a case, the first channel13aof the first separating part11may include a first coupling portion131, and the second channel13a′ of the second separating part12may include a second coupling portion132coupled to the first coupling portion131. More specifically, the first and second coupling portions131and132may be in the form of a fastener and a fastening groove, such that the first and second coupling portions131and132can be engaged to each other via the fastener and the fastening groove. In this embodiment, the first coupling portion131is a fastener, and the second coupling portion132is a fastening groove engaged with the fastener.

In the first embodiment of the present invention, the at least one first engaging portion13and the at least one second engaging portion13′ align with each other and respectively include the first and second channels13aand13a′, and the first and second channels13and13a′ respectively include the first and second coupling portions131and132. As such, the first and second separating parts11and12may be coupled to each other via the first and second coupling portions131and132, thus further enhancing the engagement therebetween. Since the first coupling portion131can be fastened to the second coupling portion132, the use of the first and second coupling portions131and132will not affect the assembly convenience of the inner-rotor motor. Furthermore, since the first coupling portion131is arranged in the first channel13a, the first coupling portion131will not be arranged outwards of the outer surface of the lateral wall B2of the first separating part11. Likewise, the second coupling portion132is arranged in the second channel13a′, therefore, the second coupling portion132will not be arranged outwards of the outer surface of the lateral wall B2of the second separating part12. In other words, since the first and second coupling portions131and132are not arranged outwards of the outer surface of the separating member1, arrangement of the first and second coupling portions131and132will not increase the radial width of the inner-rotor motor according to the first embodiment of the present invention.

Please refer toFIGS. 4 and 5, an inner-rotor motor according to a second embodiment of the present invention further includes a metallic housing4, which is different from the first embodiment. The metallic housing4is adapted to receive the separating member1(including the stator2and the permanent magnet assembly32of the rotor3). The metallic housing4may be coupled to the separating member1by screwing, engagement, press fitting or tenoning for providing a high structural strength of the inner-rotor motor, thus achieving a better protecting effect. In this embodiment, an insulating effect of the inner-rotor motor is provided via the use of the separating member1, thus preventing a leakage current between the stator2and the metallic housing4.

In this embodiment, a screwing member “S” extends through the metallic housing4and the first channel13afor fastening the separating member1in the metallic housing4. Specifically, the at least one first engaging portion13includes a plurality of first engaging portions13, and the at least one second engaging portion13′ includes a plurality of second engaging portions13′. One of the first engaging portions13includes the first channel13a. Likewise, one of the second engaging portions13′ includes the second channel13a′. In addition, the first engaging portion13aligns with the second engaging portion13′, such that the first channel13acommunicates with the second channel13a′. In this arrangement, the screwing member “S” extends through the first and second channels13aand13a′ to fasten the separating member1in the metallic housing4.

The metallic housing4includes a body41in the form of a hollow cylinder having two openings formed at two opposite ends thereof. The body41encloses the first and second separating parts11and12, and includes two lids42respectively coupled with the two openings. Each lid42includes at least one fastening hole421arranged at an outer edge thereof and aligned with the at least one first engaging portion13and the at least one second engaging portion13′. As such, the screwing member “S” extends through the at least one fastening hole421of each of the two lids42, to sandwich the separating member1between said two lids42.

In the inner-rotor motor according to the second embodiment of the present invention, the separating member1is fastened in the metallic housing4by the screwing member “S.” The screwing member “S” extends through the first and second channels13aand13a′ and is not arranged outwards of the outer surfaces of the lateral walls B2of the first and second separating parts11and12. Thus, arrangement of the screwing member “S” does not increase the radial width of the inner-rotor motor according to the second embodiment. As a conclusion, the use of the screwing member “S” will not increase the total volume of the inner-rotor motor in the second embodiment.

Please refer toFIGS. 6 and 7, an inner-rotor motor according to a third embodiment of the present invention differs from the second embodiment in that the separating member1further includes a through-hole14. The through-hole14may be arranged on the first separating part11or the second separating part12. A wire “W” may extend out of the separating member1via the through-hole14and may reach the metallic housing4. The wire “W” may be received in the first channel13aor the second channel13a′. Specifically, the inner-rotor motor of the third embodiment further includes a circuit board5that is received in the space defined by the first and second separating parts11and12and is electrically connected with one end of the wire “W.” The through-hole14may be arranged on the lateral wall B2of the second separating part12and may communicate with the second channel13a′, such that the other end of the wire “W” may extend out of the separating member1along the second channel13a′ and is located between the separating member1and the metallic housing4. In this arrangement, a power source or a controller outside the inner-rotor motor can be provided or electrically connected to the circuit board5via the wire “W.” However, the through-hole14can be arranged on the lateral wall B2of the first separating part11and can communicate with the first channel13a, which is not taken as a limited sense.

Similarly, a coil22may be wound around an outer periphery of the iron core21of the stator2. One end of the wire “W” may be electrically connected to the coil22, while the other end extends out of the inner-rotor motor along the first channel13aor the second channel13a′ of the separating member1. Thus, a power source or a controller outside the inner-rotor motor can be provided to or electrically connected to the coil22via the wire “W.”

In the inner-rotor motor according to the third embodiment of the present invention, the wire “W” extends through the through-hole14of the separating member1and is received in the first channel13aor the second channel13a′. Thus, the wire “W” is able to extend out of the inner-rotor motor along said channel13aor13a′ of the separating member1. In this arrangement, a predetermined space for the wire “W” between the separating member1and the metallic housing4is not necessary. Therefore, arrangement of the wire “W” does not increase the total volume of the inner-rotor motor.

Please refer toFIG. 8, in another implementation of the present invention, a first separating part11′ is similar to the first separating part11described above except that the first separating part11′ includes a first channel13a1being in the form of an extending hole. In other words, the first channel13a1extends through two opposite sides of the at least one first engaging portion13along the axial direction of the inner-rotor motor. As such, the appearance integrity of the first separating part11′ is not adversely affected by the arrangement of the first channel13a1. The first channel13a1may also be adapted to receive the first coupling portion131, the screwing member “S” or the wire “W.” Likewise, the second separating12may also include the second channel (not shown) in the form of an extending hole extending through two opposite sides of the at least one second engaging portion13′ along the axial direction of the inner-rotor motor.

According to the present invention, the separating member1includes at least one first engaging portion13arranged on the inner surface and protruding inwards towards the iron core. The at least one first engaging portion13may be in the form of a solid post extending along the axial direction of the inner-rotor motor. Alternatively, the at least one first engaging portion13may include a first channel13aor13a1. The first channel13amay be in the form of the receiving channel formed on the outer surface of the separating member1. On the other hand, the first channel13a1may be in the form of the extending hole extending through the two opposite sides of the at least one first engaging portion13along the axial direction of the inner-rotor motor.

According to the arrangement described above, the inner-rotor motor of the present invention is characterized as follows. The separating member1includes the at least one first engaging portion13arranged at the first separating part11, and the iron core21includes the at least one engaging groove211arranged at the outer surface thereof. The at least one first engaging portion13and the at least one engaging groove211extend along the axial direction of the inner-rotor motor, and the at least one first engaging portion13is received in the at least one engaging groove211. Thus, the iron core21is fixed relative to the separating member1, and relative rotation therebetween is also prevented. With comparison to the conventional inner-rotor motor9where the separating member92has to be screwed to the stator91, the iron core21and the separating member1in the inner-rotor motor of the present invention do not need to be coupled to each other by screwing, thus providing a convenient assembly.

Additionally, the second separating part12may also include the at least one second engaging portion13′ aligned with the at least one first engaging portion13along the axial direction of the inner-rotor motor. The at least one first engaging portion13and the at least one second engaging portion13′ may include the first and second channels13aand13a′, respectively. According to the second embodiment of the present invention, the inner-rotor motor further includes the metallic housing4and the screwing member “S” for fastening the separating member1in the metallic housing4. The screwing member “S” extends through the first and second channels13aand13a′. Since the screwing member “S” is not arranged outwards of the outer surface of the separating member1, the radial width of the inner-rotor motor will not be increased. With comparison to the traditional inner-rotor motor9where the use of screwing member “S” increases the total volume thereof, the volume of the inner-rotor motor is certainly reduced in the present invention.

Furthermore, due to the arrangement of the wire “W” that extends through the through-hole14of the separating member1and is received in the first channel13aor the second channel13a′, the wire “W” is able to extend out of the inner-rotor motor along said channel13aor13a′. With comparison to the traditional inner-rotor motor9where it is required to maintain a space between the separating member92and the metallic housing93, a predetermined space for the wire “S” between the separating member1and the metallic housing4is not needed in the present invention, thus significantly reducing the total volume of the inner-rotor motor.

As a conclusion, the inner-rotor motor of the present invention provides a convenient assembly and a reduced volume.