GLEICHSTROMMOTOR

Abstract

DC motor with four or more poles, including: a cylindrical commutator (9) formed at an axis of an anchor (8); Brushes (10) formed either from a positive brush (10a) or a negative brush (10b) arranged at an outer circumference of the commutator (9), wherein the number of positive brushes (10a) is the same as the number of negative brushes (10b); Brush holding devices (14) that hold the brushes (10); Brush pressure elements (15) which are housed in the brush holding devices (14) and which press the brushes (10) towards the commutator (9); an electrically conductive first connecting plate (16) to which all positive brushes (10a) or all negative brushes (10b) are individually electrically connected via connecting cables (18); and an electrically conductive second connecting plate (17) to which all negative brushes (10b) or all positive brushes (10a) are individually electrically connected via the connecting cables (18); wherein the brush holding device (14), of which an inner circumferential side is open in a radial direction opposite the commutator (9), and the brush holding device (14) comprises a wall (14a) at an outer circumferential side in the associated radial direction, which regulates an outer position in the radial direction of the brush pressure element (15), an anchor core side (12) in an axial direction of the brush holding device (14), which is referred to as a core side, is mounted to the first connecting plate (16), and an anchor core opposite side in the axial direction of the brush holding device (14), which is referred to as an anchor opposite side, is mounted to the second connecting plate (17); wherein the brush holding device (14) which holds the brush (10) which is connected to the first connecting plate (16) via a connecting cable (18) is referred to as a first brush holding device (14A) and the brush holding device (14) which holds the brush (10) which is connected to the second connecting plate (17) via the connecting cable (18) is referred to as a second brush holding device (14B); a slot (16a) which opens outwards in the radial direction and extends halfway to an inner side, is formed in the first connecting plate (16) at a circumferential position where the first brush holding device (14A) is arranged; and the first brush holding device (14A) has a slot insertion section (19) on the core side in the axial direction, the first brush holding device (14A) is mounted to the first connecting plate (16) by inserting the slot insertion section (19) into the slot (16a) of an outer circumferential side of the first connecting plate (16), and an outer position in the radial direction of the first brush holding device (14A) with respect to the first connecting plate (16) is regulated by a single first regulating element.

Description

BACKGROUND OF THE INVENTION Technical field of the invention

[0001] The present invention relates to a DC motor that arranges brushes held in a box-shaped brush holder on an outer periphery of a cylindrical commutator. DESCRIPTION OF THE RELATED ART

[0002] As a conventional technology, there is a brush assembly applied to a DC motor of a six-pole magnet type disclosed in Korean Patent Application KR 10 2013 0 007 793 A.

[0003] The brush assembly is provided with brushes (three positive brushes and three negative brushes, for example) arranged on an outer periphery of a cylindrical commutator and a box-shaped brush holder that holds the brushes.

[0004] The brush assembly is further provided with brush springs housed within the brush holder to urge the brushes toward the commutator, positive connecting plates for electrical connection between the positive brushes, and negative connecting plates for electrical connection between the negative brushes.

[0005] The brush holder is arranged between the positive connecting plates and the negative connecting plates, being mounted to both connecting plates from an inner peripheral side in a radial direction.

[0006] Methods for assembling the brush assembly according to the conventional technology (KR 10 2013 0 007 793 A) are considered to include the two patterns mentioned below.

[0007] 1) In a state where the positive connecting plates, all the brush holders and the negative connecting plates are assembled, the brush springs and the brushes are inserted into the brush holder in this order from an inside in a corresponding radial direction.

[0008] A support frame or mounting frame is then inserted into a central section of the brush holding device so that the brushes do not fall out towards the inner peripheral wall.

[0009] 2) In a state where the positive connecting plates and all the brush holders are assembled, the brush springs and the brushes are inserted into the brush holder in this order from an inner side in a corresponding radial direction.

[0010] Thereafter, in a state where a jig is inserted into a central portion of the brush holder so that the brushes do not fall out toward the inner peripheral side, all the brush holders are fixed to the negative connecting plates.

[0011] Since the brushes are inserted into the brush holder in a state where at least all the brush holders are mounted to the positive connection plates in the above-described assembling method, it is impossible to insert all the brushes into each brush holder from the inside in the radial direction at the same time.

[0012] In addition, when all the brushes are inserted into the brush holders one by one, it is necessary to press the brushes that have been inserted into the brush holders so that the brushes do not fall out toward the inner peripheral side.

[0013] Consequently, in the configuration of KR 10 2013 0 007 793 A, since the assemblability of the brush assembly is poor and an assembly work takes time, there is a problem that the productivity is low.

[0014] JP H06-327197 A describes a DC motor. A support plate assembly is attached to a housing, which is configured to couple a first conductive support plate connected to a negative-side brush, and a second conductive support plate connected to a positive-side brush. A first connecting part connected to the first conductive support plate so as to contact the inner surface of the housing, and the inner end of a terminal bolt, which passes through the housing in an electrically insulated state, are connected to the inner surface side of a second connecting part connected to the second conductive support plate. Then, a nut, which has an insulating member interposed between it and the outer surface of the housing, is screwed onto the outer end part of the terminal bolt.

[0015] US Pat. No. 7,256,527 B2 describes a brush holding device comprising a brush holder with a brush housing chamber and a holding plate to which the brush holder is attached. The holding plate is formed with a center hole in a corresponding center portion, the center hole being sized to allow a commutator to pass therethrough, and with a pair of elongated holes opposite each other with respect to the opening portion, the elongated holes defining bridge portions with the opening hole. The brush holder has a thick-walled portion integral with a bottom wall of the brush housing chamber, the thick-walled portion being provided with fitting grooves on its lateral sides.The bridge sections are inserted into the fitting grooves so that the brush holder is attached to the mounting plate in such a way that the thick-walled section is clamped between the bridge sections.

[0016] The publication DE 10 2007 059 555 A1 describes a brush assembly for an electrical machine. The brush assembly consists of four stacked annular plate elements, namely two outer circuit boards, each of which is electrically connected to one or more brushes, and two guide plates made of electrically insulating material arranged between them. These plates have a shape with projections and recesses to form radial guides for the brushes and receptacles for springs acting on the brushes. The springs are spiral springs wound around a mandrel, the flat ends of which project beyond the spring and are guided in a guide groove of the respective receptacle in a rotationally secure manner and can engage behind a stop.To assemble the brush unit, the circuit boards and guide plates are stacked and riveted in the axial direction, and then the brushes are pushed into the guides in the radial direction and the springs are inserted into the holders.

[0017] US 2008 / 0 083 556 A1 describes a feedthrough seal for a dynamoelectric machine. The feedthrough seal comprises a body portion of the feedthrough seal that can sealingly engage an opening in a housing of a dynamoelectric machine, and at least one extension extending from the body portion that can receive a conductor and provide electrical insulation for it.

[0018] US Pat. No. 7,592,731 B2 describes a rotating DC electric machine with a field winding wound on field-magnet iron cores and an armature with an armature winding connected in series with the field winding via a pair of brushes and a corresponding pair of connecting leads electrically connected to the brushes. A compensating winding for compensating the magnetic field strengths of the field poles is wound around and held by successive field-magnet iron cores, one end of which is fixedly connected and electrically connected to one of the connecting leads, and the other end is electrically connected and fixedly connected to the other connecting lead. SUMMARY OF THE INVENTION

[0019] The present invention has been made in view of the above-mentioned problems and has as a related object to provide a DC motor in which it is easy to mount a brush assembly and which is capable of improving productivity.

[0020] This object is achieved by a DC motor according to claim 1 or claim 2. Advantageous further developments are specified in the dependent claims.

[0021] A DC motor having four or more poles according to a first aspect includes a cylindrical commutator formed on an axis of an armature, brushes formed of positive brushes and negative brushes arranged on an outer periphery of the commutator, brush holders that hold the brushes, brush pressing members housed in the brush holders and that press the brushes toward the commutator, an electrically conductive first connection plate to which all the positive brushes or all the negative brushes are individually electrically connected via lead wires, and an electrically conductive second connection plate to which all the negative brushes or all the positive brushes are individually electrically connected via lead wires.

[0022] The brush holder, an inner peripheral side of which faces the commutator in a radial direction, is opened, the brush holder including a wall on an outer peripheral side in the corresponding radial direction that regulates an outer side position in the radial direction of the brush pressing member, an armature core side in an axial direction of the brush holder, referred to as a core side, is mounted to the first connection plate, and an armature core opposite side in the axial direction of the brush holder, referred to as a core opposite side, is mounted to the second connection plate.

[0023] When the brush holder that holds the brush connected to the first connection plate via a lead wire is referred to as a first brush holder, and the second brush holder that holds the brush connected to the second connection plate via the lead wire is referred to as a second brush holder, a slot that opens outward in the radial direction and extends halfway to an inner side is formed in the first connection plate at a circumferential position where the first brush holder is arranged, the first brush holder having a slot insertion portion on the core side in the axial direction, the first brush holder being mounted to the first connection plate by inserting the slot insertion portion into the slot from an outer peripheral side of the first connection plate,wherein an outer side position in the radial direction of the first brush holding means with respect to the first connecting plate is regulated by a single first regulating element.,

[0024] According to the above-described configuration, since it is possible to mount the first brush holder from the outer peripheral side of the first connecting plate, the mountability can be improved compared with the conventional technology of mounting the first brush holder from the inner peripheral side of the first connecting plate.

[0025] For example, by disposing a mounting jig that regulates an inside position of the brush in a radial direction at a central position in the radial direction of the first connecting plate, and by mounting the first brush holder from the outer peripheral side of the first connecting plates, the brush never falls out to the inside in the radial direction pushed by the pushing member, thus improving an assemblability of the first brush holder.

[0026] Furthermore, it is possible to mount a plurality of the first brush holding devices to the first connecting plate at the same time.

[0027] That is, since the first brush holders are mounted from the outer peripheral side of the first connecting plates, the first brush holders will not interfere with each other, and by mounting the plurality of first brush holders at the same time, the mounting process can be shortened.

[0028] A DC motor having four or more poles according to a second aspect includes a cylindrical commutator formed on an axis of an armature, brushes formed of positive brushes and negative brushes arranged on an outer periphery of the commutator, brush holders that hold the brushes, brush pressing members housed in the brush holders that press the brushes toward the commutator, an electrically conductive first connection plate to which all the positive brushes or all the negative brushes are individually electrically connected via lead wires, and an electrically conductive second connection plate to which all the negative brushes or all the positive brushes are individually electrically connected via lead wires.

[0029] The brush holder, an inner peripheral side of which faces the commutator in a radial direction, is opened, the brush holder including a wall on an outer peripheral side in the corresponding radial direction that regulates an outer side position in the radial direction of the brush pressing member, an armature core side in an axial direction of the brush holder, referred to as a core side, is mounted to the first connection plate, and an armature core opposite side in the axial direction of the brush holder, referred to as a core opposite side, is mounted to the second connection plate.

[0030] When the brush holder that holds the brush connected to the first connection plate via a lead wire is referred to as a first brush holder, and the brush holder that holds the brush connected to the second connection plate via the lead wire is referred to as a second brush holder, a slit that opens outwardly in the radial direction and extends to a radial center position is formed in the first connection plate at a circumferential position where the first brush holder is arranged, and a bridge portion that crosses at least a part of the slit in a circumferential direction is formed.crosses, is arranged on a core side in a thickness direction of the first connecting plate to connect both sides of the slot, wherein the first brush holder has a slot insertion portion on the core side in the axial direction, wherein the first brush holder is mounted to the first connecting plate by inserting the slot insertion portion into the slot from an outer peripheral side of the first connecting plate via an inner side of the bridge portion, wherein an outer side position in the radial direction of the first brush holder with respect to the first connecting plate is regulated by a single first regulating member.

[0031] According to the above-described configuration, since it is possible to mount the first brush holder from the outer peripheral side of the first connecting plate, mounting ability can be improved compared with the conventional technology of mounting the first brush holder from the inner peripheral side of the first connecting plate.

[0032] For example, by disposing a mounting jig that regulates an inner side position in a radial direction of the brush at a central position in the radial direction of the first connecting plate, and by mounting the first brush holder from the outer peripheral side of the first connecting plates, the brush never falls out to an inner side in the radial direction pushed by the pushing member, thus improving an assemblability of the first brush holder.

[0033] It should be noted that since the slot insertion portion is inserted into the slot via an inner side of the bridge portion when the first brush holder is mounted to the first connecting plate, the slot insertion portion does not interfere with the bridge portion.

[0034] Furthermore, it is possible to mount a plurality of the first brush holding devices to the first connecting plate at the same time.

[0035] That is, since the first brush holders are mounted from the outer peripheral side of the first connecting plates, the first brush holders do not interfere with each other, and the mounting process can be shortened by mounting the plurality of first brush holders at the same time. BRIEF DESCRIPTION OF THE DRAWING

[0036] They show: Fig. 1 is a perspective view of a brush assembly according to a first embodiment; Fig. 2 is a perspective view of the brush assembly in a state prior to assembly according to the first embodiment; Fig. 3 is a perspective view of a core side subassembly and a core counter side subassembly in a state before assembly according to the first embodiment; Fig. 4 is a partial sectional view of a starter according to the first embodiment; Fig. 5 is a perspective view of a brush assembly according to a second embodiment; Fig. 6 is a perspective view of the brush assembly in a state prior to assembly according to the second embodiment; Fig. 7 is a perspective view of a core side subassembly and a core counter side subassembly in a state before assembly according to the second embodiment; Fig. 8 is a connection diagram of a motor according to a third embodiment; Fig. 9 is another connection diagram of the motor according to the third embodiment; Fig. 10 is a connection diagram of a motor according to a fourth embodiment; Fig. 11 is another connection diagram of the motor according to the fourth embodiment; and Fig. 12 a connection diagram of a typical DC motor with a magnetic field system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Embodiments of the present invention are described in more detail by the following embodiments. [Exemplary Examples][First Example]

[0038] In a first embodiment, a case of using a DC motor according to the present invention in a starter for starting an engine will be described.

[0039] As it is in Fig. 4, a starter 1 has a pinion 4 arranged on an output shaft 3 which is driven and rotated by a motor 2.

[0040] The starter 1 uses a system that engages the pinion gear with a ring gear 6 of a prime mover (not shown) by rotating the pinion gear 4 in a counter-engine direction of the output shaft 3 (to the left in Fig. 4) is pushed out using an attractive force of an electromagnetic switch 5 which integrates an electromagnet or a solenoid (generally referred to as a pinion plunger type).

[0041] It should be noted that since the basic structure and operation of the starter 1 are generally known, a detailed description will be omitted, and the engine 2 according to the present invention will be described in detail below.

[0042] The motor 2 is a four-pole or more (for example, six-pole) DC motor that uses a permanent magnet 7 for an excitation pole and includes an armature 8, a cylindrical commutator 9, brushes 10, and the like. The armature 8 is arranged at an inner periphery of the excitation pole with an air gap therebetween. The commutator 9 is formed on an axis of the armature 8. The brushes 10 are arranged on an outer periphery of the commutator 9.

[0043] The commutator 9 includes a cylindrical insulator base 9a made of, for example, a resin material, and a plurality of commutator segments 9b arranged in a cylindrical shape and held by the insulator base 9a.

[0044] Then, the insulator base 9a is fixed to an outer periphery of one end of an armature shaft 11 by press fitting.

[0045] Each of the commutator segments 9b is insulated from each other by the insulator base 9a, wherein an armature coil 13 is connected to a step or vane 9c which is provided at each commutator segment 9b at one side to the armature core 12 in an axial direction (left side in Fig. 4) is provided.

[0046] The brushes 10 comprise three positive brushes 10a and three negative brushes 10b arranged alternately in a circumferential direction of the commutator 9, and form a brush assembly arranged in Fig. 1, together with brush holders 14, brush pressing members 15 and a pair of connecting plates 16, 17, which will be described below.

[0047] Each of the brush holders 14 is formed of an insulating member such as a resin or the like, as shown in Fig. 3, an inner peripheral side of the brush holder 14 is opened in a radial direction to form a box shape having a wall 14a at an outer peripheral side in the radial direction.

[0048] The brush pressing element 15 is, for example, a spiral spring and is housed in the brush holder 14. A position of the brush pressing element 15 outward in the radial direction is regulated by the wall 14a of the brush holder 14, whereby the brush 10 is pressed toward the commutator 19.

[0049] Both of the pair of connecting plates 16, 17 are made of a metal, each having a ring shape including a round hole having a larger diameter than an outer diameter of the commutator 9, being opened in a central portion in the radial direction of the connecting plates 16, 17.

[0050] The pair of connecting plates 16 and 17 includes a core-side connecting plate 16 (corresponding to a first connecting plate in the present invention) arranged on a core side in an axial direction, and a core-opposite-side connecting plate 17 (corresponding to a second connecting plate according to the present invention) arranged at a core-opposite side in the axial direction.

[0051] Incidentally, the core side in the axial direction refers to a side close to the armature core 12 (left side in Fig. 4), wherein the core opposite side in the axial direction refers to a side which is remote from the armature core 12 (right side in Fig. 4).

[0052] As it is in Fig. 3, the three positive brushes 10a are each electrically connected to a core-opposite-side surface of the core-side connecting plate 16, which is opposite to the core-opposite-side connecting plate 17 in the axial direction, by lead wires 18.

[0053] On the other hand, the three negative brushes 10b are each electrically connected to a core side surface of the core counter-side connecting plate 17, which is opposite to the core side connecting plate 16 in the axial direction, by the connecting cables or strands 18.

[0054] Further, first slots 16a are formed on the core-side connecting plate 16 at circumferential positions where the brush holders 14 holding the positive brushes 10a are arranged, and second slots 16b are formed at circumferential positions where the brush holders 14 holding the negative brushes 10b are arranged.

[0055] First slots 17a are formed on the core opposite side connecting plate 17 at circumferential positions where the brush holders 14 holding the negative brushes 10b are arranged, and second slots 17b are formed at circumferential positions where the brush holders 14 holding the positive brushes 10a are arranged.

[0056] Hereinafter, the brush holders 14 that hold the positive brushes 10a are referred to as first brush holders 14A, and the brush holders 14 that hold the negative brushes 10b are referred to as second brush holders 14B.

[0057] It should be noted that common functions and shapes between the first brush holders 14A and the second brush holders 14B are described by assigning the same reference numerals.

[0058] The first slots 16a, 17a formed in the core-side connecting plate 16 and the core-counter-side connecting plate 17 are open to the outside in the radial direction and extend halfway to the inside of the plates in the radial direction.

[0059] In contrast, the second slots 16b, 17b are open to the inside in the radial direction and extend halfway to the outside of the plates in the radial direction.

[0060] In other words, the core-side connecting plate 16 and the core-opposite-side connecting plate 17 have flat plate portions between the first slots 16a, 17a and the second slots 16b, 17b in the circumferential direction, and bridge portions 16c, 17c connecting flat plate portions adjacent to each other in the circumferential direction are formed inside the first slots 16a, 17a in the radial direction and outside the second slots 16b, 17b in the radial direction.

[0061] Incidentally, the connecting cables or strands 18 of the positive brushes 10a and the negative brushes 10b are respectively connected to the flat plate portions of the core side connecting plate 16 and the flat plate portions of the core opposite side connecting plate 17.

[0062] A core-side attachment portion to the core-side connecting plate 16 is arranged at a core-side end of the first brush holder 14A, and a core-opposite-side attachment portion to the core-opposite-side connecting plate 17 is arranged at a core-opposite-side end of the first brush holder 14A.

[0063] The core side attachment portion includes a slot insertion portion 19 inserted into the first slot 16a of the core side connecting plate 16, and a holding portion 20 formed at the core side of the slot insertion portion 19.

[0064] The slot insertion portion 19 is disposed protruding from a core side end surface of the first brush holder 14A and has an axial height substantially equal to the thickness of the core side connecting plate 16.

[0065] The holding portion 20 has a plate shape and is arranged to extend in the circumferential direction from both sides in the circumferential direction of the slit insertion portion 19, and is formed such that a circumferential dimension thereof is larger than the circumferential width of the first slit 16a.

[0066] Further, in the core-side mounting portion, a pair of guide grooves 21, with sides of the slot insertion portion 19 in the circumferential direction serving as groove bottoms thereof, are formed between the core-side end surface of the first brush holder 14A facing the height direction (axial direction) of the slot insertion portion 19 and an inner surface of the holding portion 20 (core-opposite side surface).

[0067] It should be noted that a first engagement surface and a second engagement surface recited in claim 7 of the present invention are the core side end surface of the first brush holder 14A and the inner surface of the holding portion 20 forming the guide grooves 21.

[0068] The core opposite side attachment portion includes a convex portion 22 that can be press-fitted into the second slot 17b formed in the core opposite side connecting plate 17, and a radial direction regulating portion 23 disposed inside in the radial direction of the convex portion 22.

[0069] The radial direction regulating portion 23 is arranged to be curved in an arc shape extending in the circumferential direction from both sides of the convex portions 22, and has a function of regulating an outward position in the radial direction of the brush holder 14A with respect to the core opposite side connecting plate 17.

[0070] A core-opposite-side attachment portion for the core-opposite-side connecting plate 17 is disposed at a core-opposite-side end of the second brush holder 14B, and a core-side attachment portion for the core-side connecting plate 16 is disposed at a core-side end of the second brush holder 14B.

[0071] Functions and shapes of the core opposing side attachment portion and the core side attachment portion of the second brush holder 14B are the same as those of the first brush holder 14A, thus duplicative descriptions are omitted.

[0072] It should be noted that a first engagement surface and a second engagement surface as recited in claim 8 according to the present invention are the core opposite side end surface of the second brush holder 14B and the core side surface of the holding portion 20, which form the guide grooves 21.

[0073] U-shaped grooves 24 are formed on a respective side surface in the circumferential direction of the first brush holding devices 14A and the second brush holding devices 14B for leading out the connecting cables 18.

[0074] Next, an assembly method of the brush assembly is described.

[0075] As it is in Fig. As shown in Figure 2, the brush assembly is formed by combining a core-side subassembly and a core-opposite-side subassembly. The core-side subassembly is configured by accommodating the three positive brushes 10a together with the brush pressing members 15 in the first brush holders 14A. The core-opposite-side subassembly is configured by accommodating the three negative brushes 10b together with the brush pressing members 15 in the second brush holders 14B.

[0076] As it is in Fig. 3, the core-side subassembly and the core-counter-side subassembly are assembled by placing a cylindrical mounting jig 25, which regulates inner positions in the radial direction of the positive brushes 10a and the negative brushes 10b, in a central portion in the radial direction of the subassemblies.

[0077] The core-side subassembly is formed by inserting the slot insertion portions 19 of the first brush holders 14A into the first slots 16a from the outer peripheral side of the core-side connecting plate 16.

[0078] The brush pressing members 15 and the positive brushes 10a are installed in the first brush holders 14A during the assembly process of the first brush holders 14A to the core side connecting plate 16.

[0079] The inner positions in the radial direction of the first brush holders 14A with respect to the core-side connecting plate 16 are regulated by inner side ends of the slot insertion portions 19 to abut against inner side ends of the first slots 16a.

[0080] Further, when the slot insertion portions 19 are inserted into the first slots 16a, both sides in the circumferential direction of the first slots 16a are inserted into the pairs of guide grooves 21 formed at the core side attachment portions of the first brush holders 14A.

[0081] In other words, axial positions of the first brush holders 14A with respect to the core-side connecting plate 16 are regulated by the two sides in the circumferential direction of the first slits 16a which are sandwiched between the core-side end surfaces of the first brush holders 14A forming the guide grooves 21 and the inner surfaces of the holding portions 20 (see Fig. 2).

[0082] Similar to the core-side subassembly, the second brush holders 14B are mounted to the core-opposite-side connecting plate 17 by inserting the slot insertion portions 19 provided in the second brush holders 14B into the first slots 17a from the outside in the radial direction of the core-opposite-side connecting plate 17 in the core-opposite-side subassembly.

[0083] Then, the brush assembly is formed by combining the core side subassembly and the core counter side subassembly.

[0084] In other words, the convex portions 22 provided on the core-opposite side of the first brush holders 14A are press-fitted in the axial direction into the second slots 17b formed in the core-opposite side connecting plate 17, and similarly, the convex portions 22 provided on the core-opposite side of the second brush holders 14B are press-fitted in the axial direction into the second slots 16b formed in the core-side connecting plate 16.

[0085] The outer side positions in the radial direction of the first brush holders 14A with respect to the core-opposite-side connecting plate 17 are regulated by the arcuate radial direction position regulating portions 23 formed on the core-opposite side, which abut against the inner peripheral edge of the core-opposite-side connecting plate 17, which functions as a first regulating member (see Fig. 1).

[0086] Similarly, the outer side positions in the radial direction of the second brush holders 14B with respect to the core-side connecting plate 16 are regulated by the arcuate radial direction position regulating portions 23 formed on the core side, abutting against the inner peripheral edge of the core-side connecting plate 16, which functions as the second regulating member.

[0087] The core side connection plate 16 of the brush assembly is connected to an M-connection bolt 27 (see Fig. 4) of the electromagnetic switch 5 via a conductive line member 26, and the core opposite side connecting plate 17 of the brush assembly is electrically connected to an end frame 28 (a motor housing as described in claim 15) of the motor 2, which forms a part of a ground circuit, by being fixed to the end frame 28a by a bolt 29.

[0088] It should be noted that the core-side connecting plate 16 and the core-counter-side connecting plate 17 are arranged in a line in the axial direction without being in electrical contact with each other, with the first brush holders 14A and the second brush holders 14B made of insulating materials sandwiched. [Functions and effects of the first embodiment]

[0089] 1) The brush assembly described in the first embodiment is capable of mounting the first brush holders 14A from the outer peripheral side of the core-side connecting plate 16, and is similarly capable of mounting the second brush holders 14B from the outer peripheral side of the core-counter-side connecting plate 17.

[0090] Consequently, when the first brush holders 14A and the second brush holders 14B are assembled, it is possible to prevent the positive brushes 10a and the negative brushes 10b from falling out by the mounting jig 25 arranged at the central position in the radial direction, thus improving assemblability.

[0091] 2) After mounting the first brush holders 14A to the core-side connecting plate 16, the outer side positions of the brush holders 14A in the radial direction are regulated by press-fitting the convex portions 22 of the first brush holders 14A into the second slots 17b of the core-side connecting plate 17.

[0092] Similarly, after mounting the second brush holders 14B to the core-side connecting plate 17, the positions of the second brush holders 14B outward in the radial direction are regulated by press-fitting the convex portions 22 of the second brush holders 14B into the second slots 16b of the core-side connecting plate 16.

[0093] By adopting this press-fitting structure, fixing of the first brush holders 14A and the core opposite side connecting plate 17 and fixing of the second brush holders 14B and the core side connecting plate 16 become easy.

[0094] In addition, since it is not necessary to use a separate part to regulate the positions of the first brush holders 14A and the second brush holders 14B outward in the radial direction, a number of parts does not increase.

[0095] As a result, when the brush assembly is mounted, it is easy to work, and it is possible to reduce the effort required for the work, thus improving productivity.

[0096] 3) Since the first brush holders 14A are mounted from the outer peripheral side of the core-side connecting plate 16, the first brush holders 14A can be mounted to the core-side connecting plate 16 without interfering with each other even if the three first brush holders 14A are mounted at the same time, for example.

[0097] Similarly, since the second brush holders 14B are mounted from the outer peripheral side of the core-opposite-side connecting plate 17, the second brush holders 14B can be mounted to the core-opposite-side connecting plate 17 without interfering with each other even if the three second brush holders 14B are mounted at the same time, for example.

[0098] Consequently, it is possible to shorten the assembling process by assembling the three first brush holders 14A and the three second brush holders 14B at the same time.

[0099] Other embodiments of the present invention are described below.

[0100] It should be noted that for components and compositions having commonalities to those according to the first embodiment, a detailed description thereof will be omitted by assigning the same reference numerals as in the first embodiment. [Second embodiment]

[0101] The second embodiment is a case where mounting structures of the first brush holders 14A to the core-counter-side connecting plate 17 and the second brush holders 14B to the core-side connecting plate 16 are different from the press-fitting mounting structure described in the first embodiment (the structure of press-fitting the convex portions 22 into the second slits 16b, 17b).

[0102] As it is in Fig. 7, the first brush holders 14A include second slot insertion portions 30 and position regulating portions 31 on respective core opposite sides.

[0103] The second slot insertion portions 30 have convex shapes that can be inserted into the second slots 17b from the inner peripheral side of the core opposing side connecting plate 17.

[0104] The position regulating sections 31 have functions for regulating the axial positions and the outer radial positions of the first brush holders 14A with respect to the core opposite side connecting plate 17.

[0105] The position regulating portions 31 are arranged inside in the radial direction of the second slot insertion portions 30, with fitting grooves 32 opening to the outside in the radial direction being formed thereon.

[0106] The second brush holders 14B include second slot insertion portions 30 and position regulating portions 31 on the associated core side, and have similar functions to the second slot insertion portions 30 and the position regulating portions 31 arranged in the first brush holders 14A.

[0107] As it is in Fig. 6, when the slot insertion portions 19 are inserted into the first slots 16a of the core-side connecting plate 16, the first brush holder 14A can be slidably moved further to the inner peripheral side from a position of an assembled state (a position indicated by a two-dot chain line in Fig. 6 is shown).

[0108] It should be noted that the positions of the assembled state are a state in which all the brush holders 14 in which the brush pressing members 15 and the brushes 10 are installed are mounted to the core side connecting plate 16 and the core opposite side connecting plate 17, that is, the position of the brush holders 14 outside in the radial direction in a state of the brush assembly installed in Fig. 5 is shown.

[0109] The first slot 16a of the core-side connecting plate 16 is formed longer than that according to the first embodiment, so that the first brush holder 14A can slide further toward the inner peripheral side further inward than at the positions of the assembled state.

[0110] Alternatively, as stated in Fig. 7, the first slit 16a is formed over the core side connecting plate 16 from the outer periphery to the corresponding inner periphery.

[0111] In this case, bridge portions 16c that connect flat portions formed on both sides of the first slits 16a in the circumferential direction are arranged on a core side in a plate thickness direction of the core-side connecting plate 16a (a side opposite to the side where the first brush holders 14A are arranged).

[0112] The bridge portions 16c are formed like tunnels over the first slots 16a so that the bridge portions 16c do not interfere with the slot insertion portions 19 and the holding portions 20 when the slot insertion portions 19 of the first brush holders 14A are inserted into the first slots 16a.

[0113] Although the first slit 17a is not formed across the core opposing side connecting plate 17 from the outer periphery to the inner periphery, the first slit 17a is formed longer than that according to the first embodiment, so that the second brush holder 14B can slide further inward toward the inner periphery side than at the positions of the assembled state.

[0114] Similar to the first embodiment, the first brush holders 14A and the second brush holders 14B are mounted by the cylindrical mounting frame 25 (see Fig. 7) which regulates inner side positions in the radial direction of the positive brushes 10a and the negative brushes 10b, is placed in the central portion in the radial direction of the subassemblies, and mounted to the core-side connecting plate 16 and the core-counter-side connecting plate 17, respectively.

[0115] After inserting the slot insertion portions 19 into the first slots 16a from the outer peripheral side of the core-side connecting plate 16 and sliding the first brush holders 14A further to the inner peripheral side from the assembled state positions, when returning to the assembled state positions, the second slot insertion portions 30 slide in the second slots 17b from the inner peripheral side to the outer peripheral side of the core-counter-side connecting plate 16.

[0116] When the second slot insertion portions 30 slide in the second slots 17b from the inner peripheral side to the outer peripheral side, the inner peripheral side of the core opposing side connecting plate 17 fits into the fitting grooves 32 formed in the position regulating portions 31.

[0117] This regulates the axial positions of the first brush holders 14A with respect to the core opposite side connecting plate 17.

[0118] In addition, the first brush holders 14A are regulated at the positions of the assembled state by the inner peripheral edge of the core opposite side connecting plate 17 fitted into the fitting grooves 32, abutting against the groove bottoms of the fitting grooves 32.

[0119] Alternatively, the first brush holder 14A may also be regulated at the mounted state positions by the outer peripheral edges of the second slot insertion portions 30 abutting against the outer peripheral edges of the second slots 17b.

[0120] Similar to the first brush holders 14A, after the second brush holders 14B have slid further to the inner peripheral side from the assembled state positions with respect to the core-side connecting plate 17, the second slot insertion portions 30, when returning to the assembled state positions, slide in the second slots 16b from the inner peripheral side to the outer peripheral side of the core-side connecting plate 16.

[0121] At this time, the axial positions of the second brush holders 14B with respect to the core-side connecting plate 16 are regulated by the inner peripheral side of the core-side connecting plate 16 being fitted into the fitting grooves 32 formed in the position regulating portions 31, and the second brush holders 14B are regulated at the assembled state positions by the inner peripheral edge of the core-side connecting plate 16 being fitted into the fitting grooves 32, abutting against the groove bottoms of the fitting grooves 32.

[0122] Also in the configuration according to the second embodiment, since the outer side positions in the radial direction of the first brush holders 14A are regulated by the core-opposite-side connecting plate 17 by mounting the first brush holders 14A from the outer peripheral side to the core-opposite-side connecting plate 16, and the outer side positions in the radial direction of the second brush holders 14B are regulated by the core-opposite-side connecting plate 16 by mounting the second brush holders 14B from the outer peripheral side of the core-opposite-side connecting plate 17, it is possible to obtain the same effects as in the first embodiment. [Third embodiment]

[0123] A third embodiment is a first case of a motor with an electromagnetic excitation system.

[0124] As it is in Fig. 8, the motor 2 according to the third embodiment includes a magnetic excitation system for forming excitation poles by energizing excitation coils 33 and an armature 8 having wave-wound armature coils 13, being a series-wound type in which the excitation coils 33 are connected in series with the armature coils 13.

[0125] In addition, the motor 2 has a configuration that the number of positive brushes 10a connected to the core side connection plate 16 via the lead wires 18 is less than one half of the number of excitation poles (two in Fig. 8), wherein the excitation coils 33 and the core side connecting plate 16 are electrically connected via a single lead wire 34.

[0126] In the configuration described above, it is possible to easily establish connection even if the number of ends of the exciting coils 33 connected to the core-side connection plate 16 and the number of the positive brushes 10a are different.

[0127] For example, in the case according to Fig. 8, the number of positive brushes 10a may be configured to two (or one) for a six-pole excitation magnet having the excitation coils 33 in an arrangement in which three circuits each with two coils connected in series are connected in parallel.

[0128] It should be noted that, although in Fig. 8 the case of the motor 2 of the series wound type is shown, it may be a motor of a double winding type which connects the excitation coils 33 and the armature coils 13 in series and in parallel.

[0129] Furthermore, as stated in Fig. 9, a configuration may be provided to connect the excitation coils 33 to a ground side or earth side with respect to the armature 8.

[0130] In this case, the negative brushes 10b are connected to the core side connection plate 16, and the positive brushes 10a are connected to the core opposite side connection plate 17. [Fourth embodiment]

[0131] A fourth embodiment is a second case of a motor 2 with an electromagnetic excitation system.

[0132] The motor 2 according to the fourth embodiment has features that the excitation coils 33 of all poles are series-connected or parallel-connected pairs.

[0133] An electromagnetic field that Fig. 10 is a case of 6 poles with 2 parallel circuits each with 3 coils connected in series.

[0134] In the conventional DC motor with an electromagnetic excitation system, as in Fig. 12, each of the positive brushes 10a is connected to the excitation coils 33 via the lead wire 34, respectively.

[0135] Consequently, the numbers of lead wires 34 required are the numbers of positive brushes 10a (two in Fig. 12).

[0136] In contrast, in the engine 2 according to the fourth embodiment, as shown in Fig. 10, regardless of the number of positive brushes 10a, it is possible to connect the excitation coils 33 and the core-side connecting plate 16 by a single lead wire 34, thus realizing a motor 2 with a minimum number of components and having a low cost.

[0137] As it is in Fig.11, the motor 2 according to the fourth embodiment may be configured to connect the excitation coils 33 to a ground side with respect to the armature 8.

[0138] In this case, the negative brushes 10b are connected to the core side connection plate 16, and the positive brushes 10a are connected to the core opposite side connection plate 17. [Modifications]

[0139] Although the configuration in which the positive brushes 10a are connected to the core-side connection plate 16 while the negative brushes 10b are connected to the opposite core-side connection plate 17 is described in the first and second embodiments, a configuration may be provided to connect the positive brushes 10a to the opposite core-side connection plates 17 and to connect the negative brushes 10b to the core-side connection plates 16.

[0140] Although the outer side positions in the radial direction of the first brush holders 14A and the second brush holders 14B with respect to the core-side connecting plate 16 and the core-opposite-side connecting plate 17 are regulated by the arcuate radial regulating portions 23 in the first embodiment, it is also possible to regulate the outer side positions by abutting ends of the convex portions 22 (ends on sides opposite to the radial direction regulating portions) against ends of the second slits 16b, 17b.

[0141] Although a configuration is provided that, in the first embodiment, the convex portions 22 of the first brush holders 14A are press-fitted into the second slots 17b formed in the core-opposite-side connecting plate 17 and the convex portions 22 of the second brush holders 14B are press-fitted into the second slots 16b formed in the core-opposite-side connecting plate 16, only one of the core side and the core-opposite side may employ the press-fit configuration.

[0142] Although the bridge portions 16c overlying the first slits 16a like tunnels in the circumferential direction are arranged on the core side in the thickness direction with respect to the core side connecting plate 16 in the second embodiment, it is possible to arrange similar bridge portions 17c on the core opposite side connecting plate 17.

[0143] Alternatively, the tunnel-like bridge sections 17c may be arranged only on the core opposite side connection plate 17.

[0144] In the second embodiment, the configuration is provided that after the first brush holders 14A have slid further to the inner peripheral side from the positions of the mounted state with respect to the core-side connecting plate 16, the second slot insertion portions 30, when returning to the positions of the mounted state, are inserted into the second slots 17b in the core-opposite-side connecting plate 17, and the first brush holders 14A are mounted to the core-opposite-side connecting plate 17 with the second brush holders 14B having the same configuration.

[0145] However, optionally, only one of the first brush holders 14A and the second brush holders 14B may employ the above-described configuration (the configuration of returning to the mounted state positions after sliding further into the inner peripheral side from the mounted state positions).

[0146] As described above, a first brush holder 14A is mounted on a core-side connecting plate 16 by inserting a slot insertion portion 19 into a slot 16a of an outer peripheral side of the core-side connecting plate 16, and a radially outer side position of the first brush holder 14A at the core-side connecting plate 16 is regulated by both sides in a circumferential direction of a first slot 16a inserted into a pair of guide grooves 21. A radially outer side position of the brush holder 14A is regulated by being fixed to a core-opposite-side connecting plate 17 by press-fitting a convex portion 22 provided at a core-opposite side of the first brush holder 14A into a second slot 17b of a core-opposite-side connecting plate 17.A second brush holder 14B is mounted to the core opposite side connecting plate 17 from an outer peripheral side of the core opposite side connecting plate 17, wherein a radially outer side position is regulated by the core side connecting plate 16.

Claims

[1] DC motor with four or more poles, comprising: a cylindrical commutator (9) formed at an axis of an armature (8); Brushes (10) formed of either a positive brush (10a) or a negative brush (10b) arranged at an outer periphery of the commutator (9), the number of positive brushes (10a) being the same as the number of negative brushes (10b); Brush holding devices (14) holding the brushes (10); Brush pressing elements (15) which are accommodated in the brush holding devices (14) and which press the brushes (10) towards the commutator (9); an electrically conductive first connecting plate (16) to which all positive brushes (10a) or all negative brushes (10b) are individually electrically connected via connecting cables (18); and an electrically conductive second connecting plate (17) to which all negative brushes (10b) or all positive brushes (10a) are individually electrically connected via the connecting cables (18); wherein the brush holder (14), an inner peripheral side of which in a radial direction is opposite to the commutator (9), is opened, and the brush holder (14) includes a wall (14a) at an outer peripheral side in the corresponding radial direction, which regulates an outer side position in the radial direction of the brush pressing member (15), an armature core side (12) in an axial direction of the brush holder (14), referred to as a core side, is mounted to the first connecting plate (16), and an armature core opposite side in the axial direction of the brush holder (14), referred to as an armature opposite side, is mounted to the second connecting plate (17); wherein, when the brush holding device (14) holding the brush (10) connected to the first connecting plate (16) via a lead cable (18) is referred to as a first brush holding device (14A) and the brush holding device (14) holding the brush (10) connected to the second connecting plate (17) via the lead cable (18) is referred to as a second brush holding device (14B); a slot (16a) opening outwardly in the radial direction and extending halfway to an inner side is formed in the first connecting plate (16) at a circumferential position where the first brush holding means (14A) is arranged; and the first brush holder (14A) has a slot insertion portion (19) on the core side in the axial direction, the first brush holder (14A) is mounted to the first connecting plate (16) by inserting the slot insertion portion (19) into the slot (16a) from an outer peripheral side of the first connecting plate (16), and an outer side position in the radial direction of the first brush holder (14A) with respect to the first connecting plate (16) is regulated by a single first regulating member. [2] DC motor with four or more poles, comprising: a cylindrical commutator (9) formed at an axis of an armature (8); Brushes (10) formed of either a positive brush (10a) or a negative brush (10b) arranged at an outer periphery of the commutator (9), the number of positive brushes (10a) being the same as the number of negative brushes (10b); Brush holding devices (14) holding the brushes (10); Brush pressing elements (15) which are accommodated in the brush holding devices (14) and which press the brushes (10) towards the commutator (9); an electrically conductive first connecting plate (16) to which all positive brushes (10a) or all negative brushes (10b) are individually electrically connected via connecting cables (18); and an electrically conductive second connecting plate (17) to which all negative brushes (10b) or all positive brushes (10a) are individually electrically connected via the connecting cables (18); wherein the brush holder (14), an inner peripheral side of which in a radial direction is opposite to the commutator (9), is opened, and the brush holder (14) includes a wall (14a) at an outer peripheral side in the corresponding radial direction, which regulates an outer side position in the radial direction of the brush pressing member (15), an armature core side (12) in an axial direction of the brush holder (14), referred to as a core side, is mounted to the first connecting plate (16), and an armature core opposite side in the axial direction of the brush holder (14), referred to as an armature opposite side, is mounted to the second connecting plate (17); wherein, when the brush holding device (14) holding the brush (10) connected to the first connecting plate (16) via a lead cable (18) is referred to as a first brush holding device (14A) and the brush holding device (14) holding the brush (10) connected to the second connecting plate (17) via the lead cable (18) is referred to as a second brush holding device (14B); a slit (16a) opening outwardly in the radial direction and extending to a radially central position is formed in the first connecting plate (16) at a circumferential position where the first brush holder (14A) is arranged, and a bridge portion (16c) crossing at least a part of the slit (16a) in a circumferential direction is arranged on a core side in a thickness direction of the first connecting plate (16) to connect both sides of the slit (16a), the thickness direction of the first connecting plate (16) corresponding to the axial direction of the brush holder (14);and the first brush holder (14A) has a slot insertion portion (19) on the core side in the axial direction, the first brush holder (14A) is mounted to the first connecting plate (16) by inserting the slot insertion portion (19) into the slot (16a) from an outer peripheral side of the first connecting plate (16) via an inner side of the bridge portion (16c), and an outer side position in the radial direction of the first brush holder (14A) with respect to the first connecting plate (16) is regulated by a single first regulating member; [3] DC motor (2) according to claim 1 or 2, wherein a slot (17a) opening outwardly in the radial direction and extending halfway to an inner side is formed in the second connecting plate (17) at a circumferential position where the second brush holding means (14B) is arranged; and the second brush holder (14B) has a slot insertion portion (19) on the core opposite side in the axial direction, the second brush holder (14B) is mounted to the second connecting plate (17) by inserting the slot insertion portion (19) into the slot (17a) from an outer peripheral side of the second connecting plate (17), and an outer side position in the radial direction of the second brush holder (14B) with respect to the second connecting plate (17) is regulated by a single second regulating member. [4] DC motor (2) according to claim 1 or 2, wherein a slit (17a) opening outwardly in the radial direction and extending to a radially central position is formed in the second connecting plate (17) at a circumferential position where the second brush holder (14B) is arranged, and a bridge portion (17c) crossing at least a part of the slit (17a) in a circumferential direction is arranged on a core side in a thickness direction of the second connecting plate (17) to connect both sides of the slit (17a); and the second brush holder (14B) has a slot insertion portion (19) on the core opposite side in the axial direction, the second brush holder (14B) is mounted to the second connecting plate (17) by inserting the slot insertion portion (19) into the slot (17a) from an outer peripheral side of the second connecting plate (17) via an inner side of the bridge portion (17c), and an outer side position in the radial direction of the second brush holder (14B) with respect to the second connecting plate (17) is regulated by a single second regulating member. [5] DC motor (2) according to one of claims 1 to 4, wherein the brush holding device (14) is formed from an insulating material; the first connecting plate (16) and the second connecting plate (17) are arranged in a line in the axial direction without being electrically connected to each other, wherein the brush holding device (14) is clamped; and the second connecting plate (17) also functions as the first regulating element. [6] DC motor (2) according to claim 3 or 4, wherein the brush holding device (14) is formed from an insulating material; the first connecting plate (16) and the second connecting plate (17) are arranged in a line in the axial direction without being electrically connected to each other, wherein the brush holding device (14) is clamped; and the first connecting plate (16) also functions as the second regulating element. [7] DC motor (2) according to one of claims 1 to 6, wherein at least one of a plurality of the first brush holders (14A) has a first engagement surface and a second engagement surface at both ends in the axial direction of the slot insertion portion (19), respectively; circumferential dimensions of the first engagement surface and the second engagement surface are larger than the width in the circumferential direction of the slot (16a) formed in the first connecting plate (16); a guide groove (21) is formed between the first engagement surface and the second engagement surface such that a circumferential direction side of the slot insertion portion (19) becomes a groove bottom; and both sides in the circumferential direction of the slot (16a) are inserted into the guide groove (21) and clamped between the first engagement surface and the second engagement surface in a state in which the slot insertion portion (19) is inserted into the slot (16a). [8] DC motor (2) according to one of claims 3, 4 and 6, wherein at least one of a plurality of second brush holders (14B) has a first engagement surface and a second engagement surface at both ends in the axial direction of the slot insertion portion (19), respectively; circumferential dimensions of the first engagement surface and the second engagement surface are larger than the width in the circumferential direction of the slot (17a) formed in the second connecting plate (17); a guide groove (21) is formed between the first engagement surface and the second engagement surface such that a circumferential direction side of the slot insertion portion (19) becomes a groove bottom; and both sides in the circumferential direction of the slot (17a) are inserted into the guide groove (21) and clamped between the first engagement surface and the second engagement surface in a state in which the slot insertion portion (19) is inserted into the slot (17a). [9] The DC motor (2) according to any one of claims 1 to 8, wherein at least one of the plurality of first brush holders (14A) has a convex portion (22) on a core opposite side in the axial direction, the convex portion (22) being fixed to the second connecting plate (17) by a press-fitting structure. [10] The DC motor (2) according to any one of claims 1 to 8, wherein at least one of the plurality of second brush holders (14B) has a convex portion (22) on a core side in the axial direction, the convex portion (22) being fixed to the first connecting plate (16) by a press-fitting structure. [11] DC motor (2) according to one of claims 1 to 8, wherein, when an assembled state is defined as a state in which all brush holding devices (14) are mounted to the first connecting plate (16) and the second connecting plate (17), at least one of the plurality of first brush holders (14A) is mounted to the first connecting plate (16) such that the first brush holder (14A) can slide further toward the inner peripheral side further inward than at a position of the mounted state and has a second slot insertion portion (30) on the inner peripheral side in the radial direction and on the core opposite side in the axial direction; a second slot (17b) is formed on the second connecting plate (17) from the inside to halfway toward an outside in the radial direction at a position in the circumferential position where at least one of the first brush holding devices (14A) is arranged; when a sliding position is defined as a position at which at least one of the first brush holding devices (14A) slides further inward into the inner peripheral side than a position of the mounted state with respect to the first connecting plate (16), and, when at least one of the first brush holders (14A) returns from the sliding position to the position of the mounted state, the second slot insertion portion (30) slides in the second slot (17b) from the inner peripheral side to the outer peripheral side of the second connecting plate (17). [12] DC motor (2) according to claim 11, wherein at least one of the first brush holders (14A) has a position regulating section (31) that regulates an axial position of the first brush holder (14A) with respect to the second connecting plate (17) at the inner peripheral side in the radial direction and at the core opposite side in the axial direction; a fitting groove (32) opening toward an outside in the radial direction is formed in the position regulating portion (31); and, when the second slot insertion portion (30) slides into the second slot (17b) from the inner peripheral side to the outer peripheral side of the second connecting plate (17), the axial position of at least one of the first brush holders (14A) with respect to the second connecting plate (17) is regulated by the inner peripheral side of the second connecting plate (17) being fitted into the fitting groove (32). [13] DC motor (2) according to one of claims 1 to 8, wherein, when an assembled state is defined as a state in which all brush holding devices (14) are mounted to the first connecting plate (16) and the second connecting plate (17), at least one of the plurality of second brush holders (14B) is mounted to the second connecting plate (17) such that the second brush holder (14B) can slide further toward the inner peripheral side further inward than at a position of the mounted state and has a second slot insertion portion (30) on the inner peripheral side in the radial direction and on the core opposite side in the axial direction; a second slot (16b) is formed on the first second connecting plate (16) from the inside to halfway toward an outside in the radial direction at a position in the circumferential position where at least one of the second brush holding devices (14B) is arranged; when a sliding position is defined as a position where at least one of the second brush holding devices (14B) slides further inward into the inner peripheral side than a position of the mounted state with respect to the second connecting plate (17), and, when at least one of the second brush holders (14B) returns from the sliding position to the position of the mounted state, the second slot insertion portion (30) slides in the second slot (16b) from the inner peripheral side to the outer peripheral side of the first connecting plate (16). [14] DC motor (2) according to claim 13, wherein at least one of the second brush holders (14B) has a position regulating portion (31) that regulates an axial position of the second brush holder (14B) with respect to the first connecting plate (16) at the inner peripheral side in the radial direction and at the core opposite side in the axial direction; a fitting groove (32) opening toward an outside in the radial direction is formed in the position regulating portion (31); and, when the second slot insertion portion (30) slides into the second slot (16b) from the inner peripheral side to the outer peripheral side of the first connecting plate (16), the axial position of at least one of the second brush holders (14B) with respect to the first connecting plate (16) is regulated by the inner peripheral side of the first connecting plate (16) being fitted into the fitting groove (32). [15] DC motor (2) according to one of claims 1 to 14, wherein all positive brushes (10a) are connected to the first connecting plate (16); all negative brushes (10b) are connected to the second connecting plate (17); and the second connecting plate (17) is fixed directly to a motor housing (28) which forms part of a grounding circuit, so that the second connecting plate (17) is electrically connected to the motor housing (28). [16] DC motor (2) according to one of claims 1 to 15, wherein the armature (8), of which an armature coil (13) wound around the armature core (12) is a wave winding, and an electromagnetic excitation system is provided which has excitation coils (33) connected in series or in series and parallel with the armature coils (13), and forms excitation poles by a power supply of the excitation coils (33); the number of brushes (10) connected to the first connecting plate (16) via the connecting cables (18) is less than half the number of excitation poles; and the excitation coils (33) and the first connecting plate (16) are electrically connected. [17] DC motor (2) according to one of claims 1 to 15, wherein an electromagnetic excitation system is provided which forms excitation poles by supplying power to excitation coils (33); the excitation coils (33) of all poles are connected in series or in parallel connected pairs; and the excitation coils (33) and the first connecting plate (16) are electrically connected to one another.

Images