Rotor for brush motor and on-vehicle brush motor

A rotor includes coils that are formed by winding wires around bobbins of a core, terminals which are arranged on the bobbins and to which end portions of the wires are hooked, and a commutator arranged at an end portion of the core on a side where the terminals are arranged. The terminals and commutator segments of the commutator are electrically connected via metal pieces extending from the commutator segments and via a wiring board.

TECHNICAL FIELD

The present invention relates to brush motors, in particular, to a rotor for a brush motor.

BACKGROUND ART

A rotor for a brush motor includes coils that are formed by winding wires around bobbins of a core, and a commutator that rotates integrally with the core. Each wire of the coils is electrically connected to commutator segments of the commutator, and an electric current flows through the coil when electric power is supplied to the commutator segments via so-called “brushes”. When an electric current flows through a coil, the coil generates a magnetic field. Magnetic forces among the coils of the rotor and magnets disposed on the stator cause the rotor to rotate with respect to the stator.

In general, in a rotor for a brush motor, wires are fixed to and electrically connected to commutator segments by engaging (so-called “hooking”) the end portions of the wires drawn out from the bobbins with the commutator segments. For example, in a rotor disclosed in Patent Literature 1, an engaging claw is provided on each commutator segment, and an armature wire is fused to an engaging claw in a state in which the engaging claw is bent to clamp the armature wired. Thereby, the armature wire is fixed to and electrically connected to the commutator segment.

CITATION LIST

Patent Literature

Patent Literature 1: Japanese Unexamined Utility Model Application Publication No. H04-134173

SUMMARY OF INVENTION

Technical Problem

In the conventional rotor for the brush motor, the end portions of a wire of a coil are hooked to commutator segments in a state in which the end portions of the wire are drawn out from the bobbins to the commutator. Thus, there is a problem that the length of the drawn portion of the wires is long, causing the wires to break due to inertial force during rotation of the rotor. There is another problem that a difference between a resonant state of the core and a resonant state of the commutator induced by vibration of the rotor causes the drawn wires to break.

The present invention has been made to solve the problems above, and it is an object of the present invention to provide a rotor for a brush motor that can reduce the occurrence of breakage of wires, and an on-vehicle brush motor that uses such a rotor for a brush motor.

Solution to Problem

A rotor for a brush motor in accordance with the present invention includes: a plurality of coils formed by winding wires around bobbins of a core; a plurality of terminals provided on one of the bobbins, wherein an end portion of each wire is hooked to each of the plurality of terminals; and a commutator arranged at an end portion of the core on a side where the terminals are provided, wherein the terminals and commutator segments of the commutator are electrically connected via metal pieces extending from the commutator segments and a wiring board.

Advantageous Effects of Invention

In the rotor for the brush motor in accordance with the present invention, the wires are hooked to the terminals arranged on the bobbins, and the terminals and the commutator segments are electrically connected via the metal pieces extending from the commutator segments and via the wiring board. Thereby, it is possible to eliminate the necessity of drawing out the wires from the bobbins to the commutator, and reduce the likelihood of breakage of the wires.

DESCRIPTION OF EMBODIMENTS

Hereinafter, to explain the present invention in more detail, embodiments of the present invention will be explained with reference to the attached drawings.

A rotor200of the present invention is integrally made of a core1on which coils3a-3fare wound, a commutator6, and a shaft7by insert molding. Hereinafter, with reference toFIGS. 1 to 7, a state before insert molding will be explained.

FIG. 1is a perspective view of the core1, bobbins2a-2f, and the coils3a-3f.FIG. 2is an enlarged view of a portion including a first terminal4aand a second terminal5ashown inFIG. 1.FIG. 3is a perspective view of the core1, the bobbins2a-2f, the coils3a-3f, the commutator6, and the shaft7.FIG. 4is a perspective view for illustrating a state in which the shaft7penetrates through the commutator6shown inFIG. 3.FIG. 5is an enlarged view of a portion including the first terminal4aand a first metal piece81ashown inFIG. 4.FIG. 6is a plan view of the core1, the bobbins2a-2f, the coils3a-3f, the commutator6, and the shaft7shown inFIG. 4.FIG. 7is a cross-sectional view taken along a line A-A′ shown inFIG. 6.

Note thatFIGS. 1, 3, and 4illustrate a state before fusing wires of the coils3a-3fto first terminals4a-4fand second terminals5a-5f. Also note that, inFIG. 6, as for the coils3a-3f, only one end portions31a-31fand the other end portions32a-32fof the wires are shown.

The core1is made from laminated steel plates, and has six teeth. By covering each tooth with an insulator made of, for example resin, the bobbins2a-2fare formed. Individual wires are wound around bobbins2a-2f, and coils3a-3fof so-called “concentrated winding” are constituted.

At an end of the bobbin2a, there are provided a first terminal4aand a second terminal5a. The first terminal4aand the second terminal5aare made of pure copper, and the first terminal4ais shorter in length than the second terminal5a.

The first terminal4ais provided with a hook41a. The hook41ahas a shape that is capable of clamping a linear member flexibly. As shown inFIG. 2, the end portion31aof the wire of the coil3ais fixed to the hook41aby fusing, with the end portion31aclamped by the hook41a. The second terminal5ais provided with a hook51a. The hook51ahas a shape that is capable of clamping a linear member flexibly. The other end portion32aof the wire of the coil3ais fixed to the hook51aby fusing, with the other end portion32aclamped by the hook51a.

Similarly, at each end of the bobbins2b-2f, there are provided a corresponding first terminal4b-4fand second terminal5b-5f. One end portions31b-31fof the wires of the coils3b-3fare hooked to hooks41b-41fof the first terminals4b-4f, respectively, and are fixed to the hooks41b-41fby fusing. The other end portions32b-32fof the wires of the coils3b-3fare hooked to hooks51b-51fof the second terminals5b-5f, respectively, and are fixed to the hooks51b-51fby fusing.

As shown inFIGS. 3 and 4, the commutator6having a generally cylindrical shape is arranged at an end portion of the core1on a side at which the first terminals4a-4fand the second terminals5a-5fare arranged. The commutator6has an internal space that communicates with an internal space formed in the core1, and the shaft7passes through both internal spaces.

On a side peripheral portion of the commutator6, three first commutator segments8a-8cand three second commutator segments9a-9care alternately arranged with a space provided therebetween. That is, the first commutator segment8aand the second commutator segment9aare opposed to each other via the shaft7, the first commutator segment8band the second commutator segment9bare opposed to each other via the shaft7, and the first commutator segment8cand the second commutator segment9care opposed to each other via the shaft7.

The first commutator segment8aincludes a pair of first metal pieces81a,82athat extend toward a direction from a central portion of the commutator6to the outer peripheral portion. Each first metal piece81a,82ais bent toward an axial direction of the shaft7at a substantially right angle to form an L-shape. The tip of the first metal piece81a, which is one of the first metal pieces, is in contact with the first terminal4aas shown inFIG. 5. The first metal piece81ais made of pure copper, and is fixed to the first terminal4aby, for example, TIG (Tungsten Inert Gas) welding. Similarly, the first metal piece82a, which is the other of the first metal pieces, is made of pure copper, and the tip of the first metal piece82ais in contact with the first terminal4band fixed to the first terminal4bby, for example, TIG welding.

Moreover, the first commutator segment8aincludes a second metal piece83amade of pure copper between the first metal pieces81a,82a. The second metal piece83ais bent toward an axial direction of the shaft7at a substantially right angle to form an L-shape.

Similarly, the first commutator segment8bincludes a pair of first metal pieces81b,82b. The first metal piece81b, which is one of the first metal pieces, is fixed to the first terminal4c. The first metal piece82b, which is the other of the first metal pieces, is fixed to the first terminal4d. In addition, the first commutator segment8bincludes a second metal piece83bhaving an L-shape between the first metal pieces81b,82b.

Similarly, the first commutator segment8cincludes a pair of first metal pieces81c,82c. The first metal piece81c, which is one of the first metal pieces, is fixed to the first terminal4e. The first metal piece82c, which is the other of the first metal pieces, is fixed to the first terminal4f. In addition, the first commutator segment8cincludes a second metal piece83chaving an L-shape between the first metal pieces81c,82c.

The second commutator segment9aincludes a second metal piece91athat is made of pure copper and that extend toward a direction from the central portion of the commutator6to the outer peripheral portion. The second metal piece91ais bent toward an axial direction of the shaft7at a substantially right angle to form an L-shape. Similarly, the second commutator segments9b,9crespectively include second metal pieces91b,91chaving an L-shape.

Next, with reference toFIGS. 8 to 12, a state after forming the core1, the commutator6, and the shaft7integrally by insert molding will be explained.

FIG. 8is a perspective view of the rotor200, and illustrates a wiring board11, and the rotor200without the wiring board11.FIG. 9is an enlarged view of a portion including a wiring board mounting surface101shown inFIG. 8.FIG. 10is a perspective view for illustrating a state in which the wiring board11shown inFIG. 8is mounted on the wiring board mounting surface101.FIG. 11is a plan view of the rotor200shown inFIG. 10.FIG. 12is a side view of the rotor200shown inFIG. 10.

A resin molded portion10, which has a substantially disc-shape and is made of resin used in the insert molding, is formed on an outer peripheral portion of a core-side end of the commutator6. That is, the resin molded portion10is integrated with core1to cover a commutator-side end portion of the core1.

The second terminals5a-5fand the second metal pieces83a-83c,91a-91cpenetrate through the resin molded portion10, and individual tip portions thereof project from the wiring board mounting surface101. Terminal blocks102, which support the projecting tip portions of the second terminals5a-5fand the second metal pieces83a-83c,91a-91c, are formed on the wiring board mounting surface101. In addition, the wiring board mounting surface101is provided with a plurality of cylindrical reference pins103and component placement recesses104a,104b.

The wiring board11is placed on the wiring board mounting surface101. The wiring board11includes, for example, an electronic circuit board formed with laminated wiring layers. The wiring board11has a plurality of first through-holes111, and the reference pins103of the resin molded portion10penetrate through the first through-holes111, respectively. In addition, the wiring board11has a plurality of second through-holes112, and the tip portions of the second terminals5a-5fand the second metal pieces83a-83c,91a-91care soldered to the wiring board11in a state in which the tip portions penetrate through corresponding second through-holes112.

On a surface of the wiring board11facing the wiring board mounting surface101, there is mounted a plurality of electronic components113a,113b. The electronic components113aare, for example, resistance elements, and the electronic components113bare, for example, capacitors. The electronic components113a,113bare mounted so as to be placed within the component placement recesses104a,104bof the resin molded portion10, respectively, as shown inFIG. 10.

The second terminals5a-5f, the second metal pieces83a-83c,91a-91cand the electronic components113a,113bare electrically connected through wiring in the wiring board11. Hereinafter, with reference toFIGS. 6, 11 and 13, a specific example of the wiring in the wiring board11, and an electrical connection state among the coils3a-3f, the first commutator segments8a-8cand the second commutator segments9a-9cby such wiring will be explained.

By a line114ain the wiring board11, the second metal piece83aand the second metal piece91aare connected. That is, as shown inFIG. 13, the first commutator segment8aand the second commutator segment9aare electrically connected by the line114a.

By a line114bin the wiring board11, the second metal piece83band the second metal piece91bare connected. That is, as shown inFIG. 13, the first commutator segment8band the second commutator segment9bare electrically connected by the line114b.

By a line114cin the wiring board11, the second metal piece83cand the second metal piece91care connected. That is, as shown inFIG. 13, the first commutator segment8cand the second commutator segment9care electrically connected by the line114c.

By a line114din the wiring board11, the second terminal5aand the second terminal5dare connected. Here, the first metal piece81ais welded to the first terminal4a, and the first metal piece82bis welded to the first terminal4d. Thus, as shown inFIG. 13, a state in which two coils3a,3dare connected in series between the first commutator segments8a,8bis established.

By a line114ein the wiring board11, the second terminal5cand the second terminal5fare connected. Here, the first metal piece81bis welded to the first terminal4c, and the first metal piece82cis welded to the first terminal4f. Thus, as shown inFIG. 13, a state in which two coils3c,3fare connected in series between the first commutator segments8b,8cis established.

By a line114fin the wiring board11, the second terminal5eand the second terminal5bare connected. Here, the first metal piece81cis welded to the first terminal4e, and the first metal piece82ais welded to the first terminal4b. Thus, as shown inFIG. 13, a state in which two coils3e,3bare connected in series between the first commutator segments8c,8ais established.

As explained above, with the lines114a-114fin the wiring board11, it is possible to place the first commutator segments8a-8c, the second commutator segments9a-9c, and the coils3a-3fin a state in which points of the same phase are wired and in which points of the same electrical potential are wired.

Note that, as shown inFIG. 14, by connecting individual resistance elements and individual capacitors among the second metal pieces91a-91c, so-called “snubber circuits” may be configured among the second commutator segments9a-9c. Each resistance element and capacitor of the snubber circuits115a-115care respectively provided by the electronic components113a,113bprovided on the wiring board11.

Hereinafter, in the present invention, the first terminals4a-4fand the second terminals are collectively referred to as “terminals”. One end portions31a-31fand the other end portions32a-32fof the wires of the coils3a-3fare collectively referred to as “end portions”. The first commutator segments8a-8cand the second commutator segments9a-9care collectively referred to as “commutator segments”. The first metal pieces81a-81c,82a-82cand the second metal pieces83a-83c,91a-91care collectively referred to as “metal pieces”.

Next, a brush motor including the rotor200configured as explained above will be explained.

A stator (not shown) provided with magnets is arranged so as to face the outer peripheral portion of the core1. In addition, brushes (not shown) for supplying electric power to the commutator segments8a-8c,9a-9care provided so as to come into contact with the outer peripheral portion of the commutator6. The brush motor is constituted by the rotor200, the stator, and the brushes.

Next, an operation of the brush motor, and effects of the rotor200in accordance with Embodiment 1 will be explained.

First, a power supply unit (not shown) applies a voltage to the brushes. By providing electric power from the brushes to the commutator segments8a-8c,9a-9c, electric current flows in the corresponding coils3a-3f. When the electric current flows in the coils3a-3f, the coils generate a magnetic field. Magnetic forces between the coils3a-3fof the rotor200and the magnets of the stator cause the rotor200to rotate with respect to the stator.

In response to a rotational movement of the rotor200, the commutator segments8a-8c,9a-9calternately come into contact with the brushes, and the coils in which the electric current flows are switched. Thus, the rotor200continues to rotate with respect to the stator.

No conventional rotor for a brush motor includes the terminals4a-4f,5a-5f, the metal pieces81a-81c,82a-82c,83a-83c,91a-91c, the resin molded portion10, and the wiring board11according to Embodiment 1, and the end portions of the wires of the coils are drawn out from the bobbins to the commutator and hooked to the commutator segments. Thus, there is a problem that the wires are likely to be broken because of the inertial force applied to the wires due to the rotation of the rotor, the difference between the resonant state of the core and the resonant state of the commutator induced by vibration of the rotor and so on.

In contrast, in the rotor200in accordance with Embodiment 1, the terminals4a-4f,5a-5fare provided on the bobbins2a-2f, the end portions31a-31f,32a-32fof the wires are hooked to the terminals4a-4f,5a-5f, and the wires and the commutator segments8a-8c,9a-9care electrically connected via the metal pieces81a-81c,82a-82c,83a-83c,91a-91cextending from the commutator segments8a-8c,9a-9cand via the wiring board11. Thus, it is possible to eliminate the necessity of drawing the wires out of the bobbins2a-2fto the commutator6, and reduce the likelihood of the breakage of the wires.

In addition, in the conventional rotor for the brush motor, when a plurality of the wires is fixed to one commutator segment to electrically connect therebetween, the plurality of wires is fused to the one commutator segment in a state in which the plurality of wires is hooked to a hook of the one commutator segment. Thus, there is a problem that fusing work is difficult to perform, and that a fixed state and an electrical connection state at the fused portion are unstable.

In contrast, in the rotor200in accordance with Embodiment 1, one of the first terminals4a-4fand one of the second terminals5a-5fare provided on each of the bobbins2a-2f, one end portions31a-31fand the other end portions32a-32fof the wires are hooked and fused to the corresponding first terminals4a-4fand the second terminals5a-5f, respectively. In addition, each of the first commutator segments8a-8cincludes two of the first metal pieces81a-81c,82a-82c, and each of the tip portions of the first metal pieces is in contact with a different first terminal4a-4f. Thereby, it is possible to connect two wires to each one of the first commutator segments8a-8cwithout providing the fused portion at which two or more wires are hooked to one point. Thereby, it is possible to make the fusing work easier. In addition, it is possible to stabilize the fixed state and the electrical connection state at the fused portion to enhance the structural strength of the rotor200.

Further, in the conventional rotor for the brush motor, the commutator segments are electrically connected to one another by winding electrical wires around the outer peripheral portion of the rotor. Therefore, there is a problem that it is difficult to automate a manufacturing line because it requires a step of winding the electrical wires manually in manufacturing the brush motor.

In contrast, in the rotor200in accordance with Embodiment 1, the commutator segments8a-8cand the commutator segments9a-9care electrically connected via the second metal pieces83a-83c,91a-91cextending from the commutator segments8a-8c,9a-9cand via the wiring in the wiring board11. Thus, it is possible to eliminate the step of winding the wires around the outer peripheral portion of the rotor200in manufacturing the brush motor, automate the manufacturing line for the brush motor, and reduce manufacturing costs. In particular, since only a step of attaching the wiring board11is required, it is suitable for automation.

In addition, in the rotor200in accordance with Embodiment 1, the core1, commutator6, and the shaft7are integrally formed by insert molding. Thereby, generation of the difference between the resonant state of the core1and the resonant state of the commutator6is suppressed during the rotation of the rotor200, and thus vibration resistance properties of the rotor200can be improved.

Further, in the rotor200in accordance with Embodiment 1, the wiring board11is not included as the objects of insert molding, and the resin molded portion10is interposed between the wiring board11and the coils3a-3f. Thereby, heat generated by flowing the electric current in the coils3a-3fis less likely to be transmitted to the wiring board11. Accordingly, the wiring board11may be made of a member having relatively low heat resistance properties such as an electronic circuit board. Further, by adopting the wiring board11, it is possible to easily incorporate the snubber circuits into the rotor200, as explained above.

The brush motor including the rotor200can be used for any application of a general motor. Especially, the brush motor including the rotor200is suitable for an on-vehicle brush motor because it has the properties that the wires are less likely to be broken, has the properties of high structural strength and vibration resistance, and has properties that the heat generated in the coils3a-3fis less likely to be transmitted to the wiring board11, as explained above. More specifically, it can be used for, for example, open and close control of a wastegate (WG) valve of an engine or an exhaust gas recirculation (EGR) valve of an engine.

Note that shapes and structures of the hooks41a-41f,51a-51fmay be any shapes and structures as long as the end portions31a-31f,32a-32fof the wires of the coils3a-3fcan be hooked thereto, and the shapes and structures of the hooks are not limited to the shapes and structures shown inFIGS. 1 to 7.

In addition, a shape of each of the second metal pieces83a-83c,91a-91cis not limited to the L-shape. It may be any shape as long as it can penetrate through the resin molded portion10and the tip portion thereof can project from the wiring board mounting surface101.

Moreover, when the snubber circuits are not required, the electronic components113a,113bmay not be provided on the wiring board11and the component placement recesses104a,104bmay not be formed in the resin molded portion10. In this case, the electrical connection state among the coils3a-3fand the commutator segments8a-8c,9a-9cis a state shown inFIG. 13.

Further, the wiring board11may be an electronic circuit board of a single layer, and it may be made of a copper plate.

Furthermore, a way of winding the coils3a-3fis not limited to the concentrated winding. The coils may be so-called “distributed windings” coils in which the wires are wound across a plurality of the bobbins. In this case, only one of the first terminal and the second terminal may be provided on each of the bobbins.

In addition, a shape of the core1may be any shape as long as it has a shape used for an ordinary brush motor. Moreover, the brush motor of the present invention is not limited to a 6-pole motor, and the motor may have any number of poles.

Further, the number of the first metal pieces81a-81c,82a-82cincluded in each of the first commutator segments8a-8cis not limited to two. Depending on the number of poles of the brush motor and so on, three or more first metal pieces may be included.

As explained above, the rotor200in accordance with Embodiment 1 includes: the coils3a-3fformed by winding the electrical wires around the bobbins2a-2fof the core1; the terminals4a-4f,5a-5fprovided for the bobbins2a-2fand to which the end portions31a-31f,32a-32fof the wires are hooked; and the commutator6arranged at the end portion of the core1on the side where the terminals4a-4f,5a-5fare provided. The terminals4a-4f,5a-5fand the commutator segments8a-8c,9a-9cof the commutator6are electrically connected via the metal pieces81a-81c,82a-82c,83a-83c,91a-91cextending from the commutator segments8a-8c,9a-9cand via the wiring board11. By providing the terminals4a-4f,5a-5fon the bobbins2a-2f, hooking the end portions31a-31f,32a-32fof the wires thereto, and electrically connecting the wires and the commutator segments8a-8c,9a-9cvia the metal pieces81a-81c,82a-82c,83a-83c,91a-91cextending from the commutator segments8a-8c,9a-9cand via the wiring board11, it is possible to eliminate the necessity of drawing out the wires from the bobbins2a-2fto the commutator6and reduce the likelihood of the breakage of the wires.

In addition, the terminals4a-4f,5a-5finclude the first terminals4a-4fto which one end portions31a-31cof the wires are hooked, and the second terminals5a-5fto which other end portions32a-32cof the wires are hooked and which are connected to the wiring board11. The metal pieces81a-81c,82a-82c,83a-83c,91a-91cinclude the first metal pieces81a-81c,82a-82cwhich are in contact with the first terminals4a-4f, and the second metal pieces83a-83c,91a-91cwhich are connected to the wiring board11. By adopting the configuration in which the first terminals4a-4fand the second terminals5a-5fare provided on the bobbins2a-2f, one end portions31a-31fof the wires are hooked to the first terminals4a-4f, respectively, and other end portions32a-32fof the wires are hooked to the second terminals5a-5f, respectively, it is possible to make the fusing work easier. In addition, it is possible to stabilize the fixed state and the electrical connection state at the fused portion to enhance the structural strength of the rotor200.

In addition, the commutator segments8a-8c,9a-9cinclude the first commutator segments8a-8chaving the first metal pieces81a-81c,82a-82cand the second metal pieces83a-83c, and the second commutator segments9a-9chaving the second metal pieces91a-91c. Each of the first commutator segments8a-8cincludes the plurality of first metal pieces81a-81c,82a-82c, and each of the tip portions thereof is in contact with a different first terminal among the first terminals4a-4f. Since each of the first commutator segments8a-8cincludes the plurality of first metal pieces81a-81c,82a-82cand each of the tip portions thereof is in contact with a different first terminal among the first terminals4a-4f, it is possible to eliminate the fused portion where the plurality of wires is hooked at one point even in a case in which two or more wires are connected to one of the first commutator segments8a-8c.

In addition, the first metal pieces81a-81c,82a-82cand the first terminals4a-4fare made of pure copper, and the tip portions of the first metal pieces81a-81c,82a-82care welded to the first terminals4a-4f. Since the first metal pieces81a-81c,82a-82cand the first terminals4a-4fare made of pure copper, it is possible to suppress generation of soot during the TIG welding.

Further, the rotor200includes the resin molded portion10provided on the outer peripheral portion of the core-side end portion of commutator6. The second terminals5a-5fand the second metal pieces83a-83c,91a-91cpenetrate through the resin molded portion10, and the tip portions thereof project from the wiring board mounting surface101of the resin molded portion10. The wiring board11is mounted on the wiring board mounting surface101. By interposing the resin molded portion10between the wiring board11and the coils3a-3f, it is possible that the heat generated by flowing the electric current in the coils3a-3fis less likely to be transmitted to the wiring board11.

Further, the wiring board11is the electronic circuit board, and the snubber circuits are constituted by the electronic components provided on the electronic circuit board. The snubber circuits can absorb high voltage (so-called “surge voltage”) that is generated when the commutator segments touching to the brushes are switched.

Furthermore, the rotor200includes the shaft7that penetrates through the internal spaces of the core1and the commutator6. The core1, the commutator6, and the shaft7are integrally formed by insert molding. Thereby, the generation of the difference between the resonant state of the core1and the resonant state of the commutator6is suppressed during the rotation of the rotor200, and thus the vibration resistance property of the rotor200can be improved.

With reference toFIG. 15, a rotor200in which a female thread portion71is formed on an inner peripheral portion of the shaft7will be explained. Since components other than the shaft7are the same as those in Embodiment 1, the same reference numerals are given to the same components and explanation thereof will be omitted.

The shaft7is made of metal, and has a hollow structure as shown inFIG. 15. The core1in which the coils3a-3fare wound around the bobbins2a-2f, the commutator6, and the shaft7are manufactured as separate members, and they are integrated by insert molding. The resin molded portion10and the female thread portion71on the inner peripheral portion of the shaft7are formed of the resin used in the insert molding.

The rotor200in accordance with Embodiment 2 is particularly suitable for use in an actuator that converts a rotary motion of the rotor200to a linear motion. That is, a linear shaft having a bar-shape is penetrated through the hollow interior of the shaft7, and a male thread portion provided on an outer periphery portion of the linear shaft is engaged with the female thread portion71. Thereby, when the rotor200rotates with respect to the stator (not shown), the linear shaft moves along an axial direction of the linear shaft with respect to the brush motor.

By incorporating, into the shaft7, a mechanism for converting the rotary motion of the rotor200to the linear motion, it is possible to eliminate the necessity of installing such a mechanism outside the brush motor, and thus the number of overall actuator components can be reduced. Further, since the female thread portion71and the resin molded portion10are formed of the resin used in the insert molding, it is possible to reduce the number of steps for manufacturing the brush motor, and thus the manufacturing cost of the brush motor can be reduced.

Note that it is to be understood that the above-mentioned embodiments can be freely combined, various changes can be made for any component in each of the above-mentioned embodiments, and any optional components in each of the above-mentioned embodiments can be omitted within the scope of the invention.

INDUSTRIAL APPLICABILITY

With the rotor for the brush motor according to the present invention, it is possible to reduce the likelihood of breakage of wires. Thus, the rotor for the brush motor is suitable to be used in an on-vehicle brush motor, for example, for example, for performing opening and closing control of the WG valve or the EGR valve of an engine

REFERENCE SIGNS LIST