JP2017034730A - Brush device for rotary electric machine, and rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong an available period of a brush and to secure sufficient bearing for a rectifier by making the brush further longer.SOLUTION: A brush device for a rotary electric machine comprises a spring fixing part for fixing a center part of a winding spring, and a brush holding part for holding the brush in a freely slidable manner in a radial direction of the rotary electric machine. In the brush device for the rotary electric machine, an end portion of the winding spring is brought into contact with the brush, and the brush is pressed towards a rectifier of the rotary electric machine. At a side opposite to a contact surface with the rectifier, the brush includes a slope which is inclined in such a manner that a distance from a rotation axis center of the rotary electric machine becomes longer as separated from a center part of the winding spring. In an initial state where the brush is not worn, the slope is formed in such a manner that a contact point of the end portion of the winding spring to the slope is positioned outside of any portion of the winding spring in a radial direction of the rotary electric machine in a use limit state where the brush is worn just by a predetermined amount.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a brush device for a rotating electrical machine and a rotating electrical machine.

  A rotating electrical machine is known in which the tip of a spiral spring is in contact with a brush, and the brush is biased by a commutator by the spiral spring (see Patent Document 1). In the rotating electrical machine described in Patent Document 1, in order to increase the amount of wear of the brush, the end surface of the brush with which the tip of the spiral spring contacts is inclined toward the rotor as it goes toward the spiral spring. It is an inclined surface.

Noto 2530989

  By providing an inclined surface like the brush described in Patent Document 1, it is possible to increase the effective length of the brush and extend the usage period (life) of the brush. However, in order to extend the period of use, if the length of the rotating electrical machine in the radial direction of the brush described in Patent Document 1 is further increased, in the initial state where the brush is not worn, for example, as shown in FIG. The pressing point of the winding spring deviates from the inclined surface of the brush. As a result, the moment component force MB in the radial direction of the rotating electrical machine by the winding spring is insufficient, and there is a possibility that the necessary surface pressure of the brush against the commutator cannot be secured.

The brush device for a rotating electrical machine according to claim 1 includes a spring fixing portion that fixes a central portion of the winding spring, and a brush holding portion that holds the brush slidably in the radial direction of the rotating electrical machine. In a brush device of a rotating electrical machine in which the end is brought into contact with the brush and pressed toward the commutator of the rotating electrical machine, the brush is separated from the center of the winding spring on the opposite side of the contact surface with the commutator. Therefore, it has an inclined surface that inclines so that the distance from the rotation axis center of the rotating electrical machine becomes long, and in the initial state where the brush is not worn, the winding spring for the inclined surface in the use limit state where the brush is worn by a predetermined amount The inclined surface is formed so that the contact point of the end of the coil is positioned on the radially outer side of the rotating electrical machine with respect to any part of the winding spring.
The brush device for a rotating electrical machine according to claim 2 includes a spring fixing portion that fixes a central portion of the winding spring, and a brush holding portion that holds the brush slidably in the radial direction of the rotating electrical machine. In a brush device of a rotating electrical machine in which the end is brought into contact with the brush and pressed toward the commutator of the rotating electrical machine, the brush is separated from the center of the winding spring on the opposite side of the contact surface with the commutator. Therefore, it has an inclined surface that is inclined so that the distance from the rotation axis center of the rotating electrical machine becomes longer, and the contact point of the end of the winding spring on the inclined surface in the initial state where the brush is not worn, and the center of the winding spring The inclined surface is formed so that the end of the winding spring is in contact with the inclined surface on the radially outer side of the rotating electrical machine with respect to the straight line connecting the portions.

  According to the present invention, the brush can be further lengthened to extend the use period of the brush, and a sufficient surface pressure can be ensured for the commutator.

The partial sectional view which looked at the starter concerning this embodiment from the side. II-II sectional view taken on the line of FIG. The electric circuit diagram of a starter. (A) is a figure which shows the initial state in which the brush was set, (b) is a figure which shows a brush, (c) is a figure which shows the positional relationship of a brush and a spiral spring. The figure explaining a mode that a brush wears. (A) is a figure which shows an initial state, (b) is a figure which shows the state between an initial state and a use limit state, (c) is a figure which shows a use limit state. The figure which shows the contact area | region of the spiral spring on an inclined surface. (A) is a schematic diagram for explaining the moment M by the spiral spring and the moment component force MB in the radial direction, and (b) is a relationship between the spring angle θ shown in (a), the moment M and the moment component MB. FIG. The figure which shows the brush at the time of extending the radial direction length of the brush of the brush apparatus which concerns on a prior art. The figure which shows the brush apparatus which concerns on the modification 1. FIG. The figure which shows the brush apparatus which concerns on the modifications 2-4. The figure which shows the brush apparatus which concerns on the modifications 5-7.

Hereinafter, an embodiment of a brush device for a rotating electrical machine according to the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional view of the starter according to the present embodiment as viewed from the side.

  As shown in FIG. 1, the starter includes a starter motor 1, a magnet switch 2, and a clutch mechanism 3. The magnet switch 2 operates between a connection position where the battery (not shown) and the starter motor 1 are electrically connected and a cutoff position where the electrical connection between the battery (not shown) and the starter motor 1 is cut off. It is a switch device.

  The starter motor 1 is a DC commutator motor that rotates a rotor 7 with a current supplied from a battery (not shown) via a magnet switch 2, and has a rotational driving force for starting an engine (not shown). Occur. A starter motor 1 which is a rotating electrical machine includes a cylindrical yoke 1a and a stator 9 held inside the yoke 1a.

  On the inner peripheral side of the stator 9, a rotor 7 is rotatably held through a gap. The rotor 7 includes a rotor iron core having a plurality of slots 5 formed on the outer periphery thereof, and a rotor winding 6 inserted into each slot 5. A commutator 20 (also called a commutator) connected to the rotor winding 6 is provided on one end side (the left side in the figure) of the rotor 7. The commutator 20 is a member that switches the current flowing through the rotor winding 6, and is joined to the end of the rotor winding 6 disposed along the end surface of the rotor core.

  The rotor core and commutator 20 are fixed to the rotating shaft 4. Both ends of the rotating shaft 4 are rotatably supported by bearings 4a and 4b. A driving gear 10 is formed at the end of the rotating shaft 4 on the clutch mechanism 3 side. A current is supplied to the rotor winding 6 from the battery via the brush 171 and the commutator 20. When a current is supplied to the rotor winding 6, a plurality of magnetic poles are formed on the rotor 7 in the circumferential direction. A cylindrical stator 9 constituting a magnetic circuit is disposed on the outer peripheral side of the rotor 7. When a current is passed through the rotor winding 6, the rotor 7 and the rotating shaft 4 rotate integrally with the stator 9.

  The clutch mechanism 3 is provided so as to be movable in a cylindrical one-way clutch 12 and a direction parallel to the central axis CLr of the rotary shaft 4 (hereinafter simply referred to as an axial direction) on the inner periphery of the one-way clutch 12. A pinion shaft 13 and a ring gear 14 for transmitting power to a crankshaft (not shown) of the engine are provided. A pinion 15 is provided at the tip of the pinion shaft 13. A driven gear 11 that meshes with the drive gear 10 of the rotating shaft 4 of the starter motor 1 is formed on the outer periphery of the one-way clutch 12. The clutch mechanism 3 is configured such that the pinion 15 meshes with the ring gear 14 when the pinion shaft 13 moves in one axial direction.

  The one-way clutch 12 includes an outer clutch portion 12a in which a driven gear 11 is formed on the outer periphery, an inner clutch portion 12b disposed inside the outer clutch portion 12a, and an outer clutch portion 12a and an inner clutch portion 12b. And a plurality of rollers 12c. The one-way clutch 12 is configured such that rotation from the outer clutch portion 12a to the inner clutch portion 12b is transmitted, but rotation from the inner clutch portion 12b to the outer clutch portion 12a is not transmitted. Both ends of the outer clutch portion 12a in the axial direction are rotatably supported by a pair of ball bearings 16a and 16b as bearings.

  A pinion shaft 13 is disposed on the inner periphery of the inner clutch portion 12b so as to be movable in the axial direction. A helical spline 17b that engages with a helical spline 17a provided on the inner periphery of the inner clutch portion 12b and transmits the rotational driving force of the starter motor 1 to the pinion shaft 13 is provided on the outer periphery of the pinion shaft 13. In the helical splines 17a and 17b, when the rotational speed of the inner clutch portion 12b is larger than the rotational speed of the pinion shaft 13, the pinion shaft 13 moves to the ring gear 14 side, and the rotational speed of the pinion shaft 13 becomes lower than that of the inner clutch portion 12b. The pinion shaft 13 is inclined so as to move away from the ring gear 14 when the rotational speed is higher.

  For this reason, in a state before starting the engine, the pinion shaft 13 moves to the ring gear 14 side, and the pinion shaft 13 and the inner clutch portion 12b rotate integrally. When the rotational speed of the ring gear 14 is higher than the rotational speed of the pinion shaft 13 as after the engine is started, the friction generated at the sliding portion of the one-way clutch 12 and the action of the helical splines 17a and 17b. As a result, the pinion shaft 13 moves slowly in a direction away from the ring gear 14. The pinion shaft 13 is urged in a direction away from the ring gear 14 by a coil spring 19 as an urging member disposed between the receiving portion 18 fixed to the end of the pinion shaft 13 and the inner clutch portion 12b. ing.

  A lever 23 is swingably disposed between the starter motor 1 and the magnet switch 2. As will be described later, when the ignition key 24 (see FIG. 3) is turned on and the movable iron core 27 is sucked toward the fixed contacts 21a and 22a (see FIG. 3), the lever 23 swings and the end of the lever 23 Presses the receiving portion 18 of the pinion shaft 13. When the receiving portion 18 is pressed by the lever 23, the pinion shaft 13 moves, and the pinion 15 and the ring gear 14 are engaged.

  A brush device 100 is provided at one end (the left end in the figure) of the starter motor 1. FIG. 2 is a view of the brush device 100 as viewed from the axial direction, and is a cross-sectional view cut along a plane along the line II-II in FIG. 1. As shown in FIG. 2, the brush device 100 includes a positive-side brush 171 p and a negative-side brush 171 n (generally referred to as brush 171), and a spiral that urges each brush 171 toward the commutator 20. A spring 161 and a holding plate 153 to which a holding member 151 holding each brush 171 and each spiral spring 161 is fixed are provided.

  The holding plate 153 is an annular plate, and is fixed to the bottom of the bottomed cylindrical rear bracket 41 shown in FIGS. 1 and 2 with screws. In the starter motor 1 of this embodiment, as shown in FIG. 1, the opening of the rear bracket 41 and the opening of one end of the yoke 1a are engaged, and the opening of one end of the front bracket 42 and the yoke 1a are engaged. The opening at the other end is engaged, and the rear bracket 41 and the front bracket 42 are fastened with bolts. Thereby, the rear bracket 41, the yoke 1a, and the front bracket 42 are connected.

  As shown in FIG. 2, four holding members 151 are attached to the holding plate 153 at equal intervals in the circumferential direction. A holding member 151 that holds each of the two brushes 171p on the positive electrode side is attached to the holding plate 153 via an insulating material 152, and a holding member 151 that holds each of the two brushes 171n on the negative electrode side is directly held. It is attached to the plate 153. The holding member 151 is a plate member having a pulse wave cross-sectional shape, and a pair of mounting pieces 151a fixed to the holding plate 153, and side plates 151b and 151c bent 90 degrees from each mounting piece 151a to the stator 9 side. In addition, a connecting plate (not shown) that is bent 90 degrees toward the other side plate 151b, 151c at the end of the side plate 151b, 151c and connects the pair of side plates 151b, 151c to each other is provided.

  The holding member 151 defines a cubic space in which the brush 171 is accommodated by the pair of side plates 151 b and 151 c, a connecting plate (not shown), and the holding plate 153. A brush 171 is disposed in this space, and the brush 171 is arranged in the circumferential direction of the starter motor 1 (hereinafter simply referred to as the circumferential direction) by the holding plate 153, the pair of side plates 151b and 151c, and the connecting plate (not shown). And movement in the axial direction are restricted. On the other hand, the brush 171 is allowed to move in the radial direction of the starter motor 1 (hereinafter simply referred to as the radial direction). That is, the holding member 151 holds the brush 171 slidably in the radial direction. In addition, one side plate 151c of the pair of side plates 151b and 151c has a U-shape in which a radially outer side is opened and a radially inner side is a bottom surface so that a pigtail 181 described later can move in the radial direction. Grooves are formed.

  The brush 171 is a rectangular parallelepiped member whose main component is carbon having conductivity, and supplies the current supplied from the battery to the commutator 20. The brush 171 has an end surface on the rotating shaft 4 side as a contact surface 179 that contacts the commutator 20, and an end surface opposite to the contact surface 179 as a pressing surface that is pressed by the pressing portion 163 of the spiral spring 161. . Details of the shape of the pressing surface will be described later.

  The spiral spring 161 is a mechanical element in which a thin plate is wound in a spiral shape, and is provided with a flat plate-like fixing portion 162 at one end, wound in a spiral shape around the fixing portion 162, and the other end protruding toward the brush 171 side. This is a semicircular arc-shaped pressing portion 163. The arc-shaped pressing portion 163 has an outer peripheral surface that is in contact with the brush 171. A flat plate portion 151d that protrudes toward the stator 9 in parallel to the axial direction is provided at one end portion of the pair of attachment pieces 151a. The flat plate portion 151d is disposed in the central opening of the spiral spring 161, and the fixing portion 162 of the spiral spring 161 is fixed to one surface of the flat plate portion 151d. That is, the flat plate portion 151 d is a fixing member that fixes the central portion of the spiral spring 161. In this way, by setting one end of the spiral spring 161 to the holding plate 153 and bringing the other end of the spiral spring 161 into contact with the pressing surface of the brush 171, the brush 171 is moved by the elastic force of the spiral spring 161. It is pressed toward the commutator 20.

  FIG. 3 is an electric circuit diagram of the starter. As shown in FIG. 3, the magnet switch 2 includes an external input terminal 22 electrically connected to the battery B and an M terminal electrically connected to the positive brush 171p via the positive lead wire 31p. 21. Although not shown, a terminal portion provided at one end of the positive lead wire 31p is fixed to the M terminal 21 with screws. The magnet switch 2 includes a solenoid 25 having a movable iron core 27 and a coil 26 that drives the movable iron core 27. The movable iron core 27 is provided with a movable contact 27 a that can connect or disconnect the M terminal 21 and the external input terminal 22.

  As shown in FIG. 2, the rear bracket 41 is provided with a through hole, and an insulating bush 35 is attached to the through hole. The positive lead wire 31 p is inserted into the rear bracket 41 from the outside of the rear bracket 41 via the bush 35. Although not shown, the positive lead wire 31p is connected to the positive pigtail 181p. As shown in FIG. 2, the positive-side pigtail 181p is fixed to the positive-side brush 171p. A negative electrode side pigtail 181n is fixed to the negative electrode side brush 171n, and the negative electrode side pigtail 181n is electrically connected to the rear bracket 41 (earth) via a holding plate 153. The positive-side pigtail 181p and the negative-side pigtail 181n will be described as the pigtail 181 when collectively referred to.

The operation of the starter will be described with reference to FIG.
As shown in FIG. 3, when the ignition key 24 is turned on, a current is passed from the battery B to the coil 26 of the solenoid 25, and the movable iron core 27 is on the fixed contact 21 a side of the M terminal 21 and the fixed contact 22 a side of the external terminal 22. Sucked into. When the movable iron core 27 is attracted to the fixed contacts 21a and 22a and the movable contact 27a contacts the battery-side fixed contact 22a and the motor-side fixed contact 21a, the battery-side fixed contact 22a and the motor-side fixed contact 21a are connected. A conductive state is established via the movable contact 27a.

  The current introduced from the battery B into the starter is transferred from the M terminal 21 of the magnet switch 2 to the positive lead wire 31p → the positive pigtail 181p → the positive brush 171p → the positive brush 171p of the commutator 20. Flows from the segment in contact to the rotor winding 6 (not shown in FIG. 3). The current introduced into the rotor winding 6 flows from the segment of the commutator 20 in contact with the negative brush 171n → the negative brush 171n → the negative pigtail 181n → the rear bracket 41 (ground).

  Thereby, a rotational force is generated in the rotor 7 shown in FIG. 1, and the generated rotational force is transmitted to the pinion 15 via the rotating shaft 4 to start the engine. After the engine is started, the ignition key 24 is returned to open the contact of the magnet switch 2, the current is cut off, and the starter stops.

  FIG. 4A is a diagram illustrating a state where the brush 171 is set, and illustrates an initial state where the brush 171 is not worn. FIG. 4B is a diagram showing the brush 171, and FIG. 4C is a diagram showing the positional relationship between the brush 171 and the spiral spring 161. 4 (a) and 4 (c) are partially enlarged views of FIG. Since the configuration on the positive electrode side and the configuration on the negative electrode side are substantially the same, the configuration on the positive electrode side will be described as a representative, and the description on the configuration on the negative electrode side will be omitted.

  The brush 171 is arranged extending in the radial direction. Hereinafter, for convenience of explanation, the length direction of the brush 171 shown in FIG. 4A is the y-axis direction, the direction parallel to the central axis CLr (see FIG. 1) of the rotating shaft 4 is the z-axis direction, the y-axis direction, and The direction orthogonal to each of the z-axis directions will be described as the x-axis direction.

  As shown in FIG. 4, the brush 171 has a pair of side surfaces 175 a and 175 b parallel to the yz plane, and a radially inner surface is a contact surface 179 that contacts the commutator 20, and is opposite to the contact surface 179. Is provided with a projecting portion 178 projecting radially outward.

  The brush 171 has an inner plane 172 parallel to the xz plane, an inclined plane 173 inclined by an angle α from the xz plane, and an outer plane 174 parallel to the xz plane on the opposite side of the contact surface 179 that contacts the commutator 20. have. That is, the protrusion 178 described above has an inclined surface 173 and an outer flat surface 174. The inner plane 172 extends toward the inclined surface 173 from the end of the side surface 175a near the peripheral wall of the rear bracket 41. The inclined surface 173 extends from the inner plane 172 toward the outer plane 174, and is inclined so as to approach the peripheral wall of the rear bracket 41 as the distance from the inner plane 172 increases.

  When the center point of the spiral spring 161 is O1, the center point of the rotating shaft 4 is O2, and an arbitrary position on the inclined surface 173 is T, the inclined surface 173 extends from the center point O1 of the spiral spring 161 to an arbitrary position T. As the distance O1T increases, that is, as the distance from the center point O1 increases, the distance O2T from the center point O2 to the position T of the rotating shaft 4 is inclined. The outer flat surface 174 extends from the end of the inclined surface 173 closer to the peripheral wall of the rear bracket 41 toward the side surface 175b.

  In the initial state where the brush 171 is not worn, the pressing portion 163 is in contact with the inner flat surface 172 at the point Q and in contact with the inclined surface 173 at the point P. That is, the inner flat surface 172 and the inclined surface 173 are pressing surfaces with which the pressing portion 163 of the spiral spring 161 is in contact. In the present embodiment, the spiral spring 161 can be stably disposed by bringing the pressing portion 163 of the spiral spring 161 into contact with the brush 171 at two points, and the initial position can be easily positioned. it can.

  The pigtail 181 is connected to the side surface 175b of the brush 171. The pigtail 181 includes a fixing portion 182 fixed inside the brush 171 and an exposed portion 183 extending from the fixing portion 182 to the outside of the brush 171. The fixing portion 182 of the pigtail 181 is disposed on the protruding portion 178.

  The manner in which the brush 171 is worn will be described with reference to FIG. FIG. 5A shows an initial state where the brush 171 is not worn. FIG. 5C shows a use limit state in which the brush 171 is worn by a predetermined amount. FIG. 5B shows a state between the initial state and the use limit state.

  As shown in the figure, the brush 171 is pressed toward the commutator 20 by the pressing portion 163 of the spiral spring 161 and is worn by contact with the commutator 20, and the length in the radial direction gradually decreases. As shown in FIG. 5A, the pressing portion 163 of the spiral spring 161 is in contact with the inner flat surface 172 and the inclined surface 173 in the initial state (Q point, P point) as shown in FIG. 5B. Thus, when wear progresses, the pressing portion 163 of the spiral spring 161 contacts only the inclined surface 173 (point P). Similarly, as shown in FIG. 5C, in the use limit state, the pressing portion 163 of the spiral spring 161 is in contact with only the inclined surface 173 and is not in contact with the inner flat surface 172.

  The contact point P of the spiral spring 161 on the inclined surface 173 is the side 175b side opposite to the side surface 175a from the side surface 175a facing the center point O1 of the spiral spring 161 as the wear of the brush 171 progresses from the initial state. Move towards.

  As shown in FIG. 5A, in the initial state, the boundary section 181b between the fixed portion 182 and the exposed portion 183 in the pigtail 181 is the xz plane passing through the contact point P of the pressing portion 163 of the spiral spring 161 with respect to the inclined surface 173. Is located on a virtual plane V parallel to.

  As wear progresses, as shown in FIG. 5B, the pigtail 181 moves toward the commutator 20 along a U-shaped groove provided in the side plate 151b. As shown in FIG. 5C, when the pigtail 181 comes into contact with the bottom surface of the U-shaped groove, the brush 171 is restricted from moving further inward in the radial direction. This state is defined as a use limit state. That is, the wear amount of the brush 171 is regulated to a predetermined amount by the U-shaped groove. In the use limit state, the boundary cross section 181b of the pigtail 181 is located radially inward from the contact point P of the pressing portion 163 of the spiral spring 161 with respect to the inclined surface 173. That is, the boundary cross section 181b of the pigtail 181 is located radially inward of the virtual plane V.

  FIG. 6 is a diagram showing a region where the contact point P of the spiral spring 161 on the inclined surface 173 moves from the initial state to the use limit state, that is, the contact region 173a of the spiral spring 161. FIG. 6B is an enlarged view of a portion D in FIG. In FIG. 6, Ps is the contact point P of the pressing part 163 with respect to the inclined surface 173 in the initial state, and Pe is the contact point P of the pressing part 163 with respect to the inclined surface 173 in the use limit state. In FIG. 6, the illustration of the pigtail 181 and the hatching showing the cross section of the brush 171 are omitted.

  As schematically shown by a thick line in FIG. 6, the contact region 173a on the inclined surface 173 is located radially outside the straight line Ns connecting the center point O1 of the spiral spring 161 and the contact point Ps in the initial state. . In other words, the angle α with respect to the xz plane of the inclined surface 173 is determined so that the pressing portion 163 of the spiral spring 161 is in contact with the inclined surface 173 radially outside the straight line Ns. It is larger than the angle θs formed by the straight line Ns and the xz plane (α> θs).

  The contact point Pe in the use limit state is the top of the inclined surface 173, and is a point where the inclined surface 173 and the outer flat surface 174 intersect. In the present embodiment, in the initial state, the inclined surface is set such that the contact point Pe of the pressing portion 163 of the spiral spring 161 with respect to the inclined surface 173 in the use limit state is located radially outside of any portion of the spiral spring 161. 173 is formed. That is, as shown in the figure, the entire spiral spring 161 is located inside a circle C with the center point O2 of the rotation shaft 4 as the center.

  FIG. 7A is a schematic diagram for explaining the moment M by the spiral spring 161 and the moment component MB in the radial direction, and FIG. 7B shows the spring angle θ and the moment shown in FIG. It is a figure which shows the relationship between M and moment component force MB. The spring angle θ is an angle formed by a straight line N connecting the center point O1 of the spiral spring 161 and the contact point P on the inclined surface 173 and the xz plane. The spring angle θ can also be defined as an angle formed by the moment M generated by the spiral spring 161 and the yz plane. The moment component MB is a y component of the moment M.

  In the brush device that presses the brush 171 toward the commutator 20 by the spiral spring 161, if the spring angle θ is too close to 90 degrees, that is, if the spring angle θ is too large, the moment component MB decreases, and the commutator 20. The contact pressure of the brush 171 on the contact surface (hereinafter also simply referred to as surface pressure) is insufficient. On the other hand, since the moment M decreases as the spring angle θ decreases, the surface pressure of the brush 171 is insufficient even when the spring angle θ is too small.

  In the present embodiment, the range of the spring angle θ is set so that the surface pressure of the brush 171 is substantially constant from the initial state to the use limit state. In the initial state, the spring angle θ is θs (for example, about 39 degrees), and in the use limit state, the spring angle θ is θe (for example, about 16 degrees). The minimum value of the moment component force MB between the initial state and the use limit state is the value Mmin1 when the spring angle θ is θs, and the maximum value is the value Mmax when the spring angle θ is θx. Mmin1 is a value larger than the moment component force that can generate a surface pressure that can obtain a sufficient rectifying effect. If the surface pressure of the brush is too large, the rotational resistance of the rotor 7 increases, and the power required for rotation increases. For this reason, Mmax is set so that the rotational resistance is smaller than a predetermined value. In the present embodiment, the difference between Mmax and Mmin1 is small, and the surface pressure can be kept substantially constant from the initial state to the use limit state.

  FIG. 8 shows a brush 971 in which the length in the radial direction of the brush according to the technique described in Patent Document 1 (hereinafter referred to as the conventional technique) is extended to the same extent as that of the present embodiment. The length in the radial direction of 175b is set to the same length as in the present embodiment.

  When the brush of the prior art has the same length as the brush 171 of the present embodiment, the contact point P of the spiral spring 161 deviates from the inclined surface 973 of the brush 971 in the initial state as shown in FIG. At this time, the spring angle θ is θcs (for example, about 53 degrees), and the moment component MB is Mmin2 as shown in FIG. 7B. Mmin2 is smaller than Mmin1, and when the difference between Mmax and Mmin1 (Mmax−Mmin1) is ΔMB, the difference between Mmax and Mmin2 (Mmax−Mmin2) is about 4.6 times ΔMB. Since the surface pressure obtained by Mmin2 is very small compared to the present embodiment, the rectifying effect is greatly deteriorated.

  As described above, when the radial length of the conventional brush is extended, the moment component MB by the spiral spring 161 is insufficient in the initial state, and the required surface pressure cannot be ensured for the commutator 20.

According to this embodiment described above, the following operational effects can be obtained.
(1) The brush 171 has an inclined surface 173 inclined to the opposite side of the contact surface with the commutator 20 so that the distance from the center point O2 of the rotating shaft 4 increases as the distance from the center point O1 of the spiral spring 161 increases. have. In the initial state where the brush 171 is not worn, the contact point Pe of the end of the spiral spring 161 with respect to the inclined surface 173 in the use limit state where the brush 171 is worn by a predetermined amount is radially outside of any part of the spiral spring 161. The angle α of the inclined surface 173 is set so as to be located at. Further, the end of the spiral spring 161 is inclined on the radially outer side than the straight line Ns connecting the contact point Ps of the end of the spiral spring 161 in the initial state on the inclined surface 173 and the center point O1 of the spiral spring 161. The angle α of the inclined surface 173 is set so as to come into contact with 173.
In this way, by setting the angle α formed by the xz plane and the inclined surface 173 to be larger than that in the prior art, in the initial state, the spring angle θ of the spiral spring 161 is made smaller than that of the brush 971 shown in FIG. can do. As a result, compared to the brush device described in Patent Document 1, the effective length of the brush (that is, the length of the portion worn from the initial state to the use limit state) can be increased and used from the initial state. Until the limit state, the surface pressure between the commutator 20 and the brush 171 can be kept substantially constant. That is, according to the present embodiment, it is possible to extend the period of use and to obtain a stable rectifying effect over a long period of time as compared with the brush device described in Patent Document 1.
Further, according to the present embodiment, the effective length of the brush 171 can be extended without changing the components other than the brush device 100 (for example, the yoke 1a and the rear bracket 41).

(2) The brush 171 has an inner flat surface 172 and an inclined surface 173 inclined with respect to the inner flat surface 172 on the opposite side of the contact surface with the commutator 20. In the initial state, the end of the spiral spring 161 is in contact with each of the inner plane 172 and the inclined surface 173, and in the use limit state, the end of the spiral spring 161 is in contact with the inclined plane 173 and in contact with the inner plane 172. The inner plane 172 and the inclined surface 173 are formed so as not to occur.
By bringing the end of the spiral spring 161 into contact with the brush 171 at two points, the spiral spring 161 can be stably disposed, and the initial position can be easily positioned. As a result, the assembly workability can be improved, and the number of work steps and production costs can be reduced.

(3) The pigtail 181 was fixed to the protrusion 178 having the inclined surface 173. In the initial state, the boundary section 181b between the fixed portion 182 and the exposed portion 183 in the pigtail 181 is on the virtual plane V orthogonal to the length direction of the brush 171 passing through the contact point Ps of the end of the spiral spring 161 with respect to the inclined surface 173. Is located. Since the protruding portion 178 is not a portion that contacts the commutator 20, that is, a portion that does not wear, if the pigtail 181 is fixed to the protruding portion 178, the effective length of the brush 171 is not affected. That is, according to the present embodiment in which the pigtail 181 is fixed to the protruding portion 178, the brush bracket without increasing the diameter of the rear bracket 41 compared to the case where the pigtail 181 is fixed radially inward of the protruding portion 178. The effective length of 171 can be set longer.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
In the above-described embodiment, the example in which the pressing surface is configured by the inner flat surface 172 and the inclined surface 173 (see FIG. 4B) has been described, but the present invention is not limited to this. For example, as shown in FIG. 9, the inclined surface 273 may be formed from the end of the side surface 175 a to the outer flat surface 174 without forming the inner flat surface 172. The inclination angle of the inclined surface 273 with respect to the xz plane is the same as the inclination angle α of the inclined surface 173 described above.

  According to the first modification, the same operational effects as (1) and (3) described in the above embodiment can be obtained. Note that, since the initial position can be easily set by providing the inner flat surface 172 as in the above-described embodiment, it is preferable to provide the inner flat surface 172. Further, as shown in FIG. 9B, in the brush 271 according to the first modification, the end portion of the side surface 175a of the brush 271 is detached from the side plate 151b of the holding member 151 in the use limit state, and rattles during use. May occur. Therefore, in the first modification, it is preferable that the height of the bottom surface of the U-shaped groove of the side plate 151c is positioned on the radially outer side than the above-described embodiment.

(Modification 2)
The surface on the opposite side of the contact surface 179 that contacts the commutator 20 is not limited to the shape of the above-described embodiment or modification 1. As shown in FIG. 10A, the inner plane 172 and the outer plane 174 may be omitted, and the inclined surface 373 may be formed from the side surface 175a to the side surface 175b. In addition, by forming the outer flat surface 174 of the above-described embodiment, by removing a portion protruding radially outward from the contact point Pe at the end of the spiral spring 161 in the use limit state, the rear bracket 41 can be removed. The diameter can be reduced. That is, the starter motor 1 can be made compact.
(Modification 3)
Instead of the inner plane 172 parallel to the xz plane shown in FIG. 4, as shown in FIG. 10B, an inner plane 472 inclined with respect to the xz plane may be provided. In the initial state, the initial position can be easily set by adopting a configuration in which the end of the spiral spring 161 is in contact with the inner plane 472 at the point Q and in contact with the inclined surface 173 at the point P.
(Modification 4)
Instead of the inner plane 172 parallel to the xz plane shown in FIG. 4, a curved surface 572 that swells radially outward may be provided as shown in FIG.
In the initial state, the end position of the spiral spring 161 is in contact with the curved surface 572 at the point Q, and the inclined surface 173 is in contact with the point P, so that the initial position can be easily set.

(Modification 5)
Instead of the inclined surface 173 shown in FIG. 4, for example, as shown in FIG. 11A, a curved surface 673 that swells radially outward may be provided.
(Modification 6)
Instead of the inclined surface 173 shown in FIG. 4, for example, as shown in FIG. 11B, a curved surface 773 that is recessed radially inward may be provided.

(Modification 7)
In the above-described embodiment, the example in which the inner plane 172 and the inclined surface 173 in contact with the spiral spring 161 are continuous in the initial state has been described (see FIG. 4), but the present invention is not limited to this. As shown in FIG. 11C, an intermediate portion 877 where the spiral spring 161 does not contact may be provided between the first plane 872 and the second plane 873 where the spiral spring 161 contacts in the initial state. Although not shown, the ends of the spiral spring 161 may be brought into contact with each other at three or more points in the initial state. For example, the ends of the spiral spring 161 may be connected to the first plane 872 and the second plane 873 in the initial state. You may make it contact each of the intermediate part 877.

(Modification 8)
In the embodiment described above, the spiral spring 161 has been described as an example of the spiral spring that presses the brush 171, but the present invention is not limited to this. The winding spring may be an elastic body capable of generating a rotational moment around the center of the spring, and may be, for example, a torsion coil spring (torsion bar spring) in addition to the spiral spring.

(Modification 9)
In the above-described embodiment, the example in which the starter motor 1 is adopted as the rotating electrical machine to which the brush device is applied has been described, but the present invention is not limited to this. Further, the present invention is not limited to a DC commutator motor, and the present invention may be applied to an AC commutator motor.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1 Starter motor, 1a yoke, 2 Magnet switch, 3 Clutch mechanism, 4 Rotating shaft, 7 Rotor, 9 Stator, 20 Commutator, 31p Lead wire, 41 Rear bracket, 100 Brush device, 151 Holding member, 151a Mounting piece 151b, 151c Side plate, 151d Flat plate portion, 152 Insulating material, 153 Holding plate, 161 Spiral spring, 162 Adhering portion, 163 Pressing portion, 171 Brush, 172 Inner plane, 173 Inclined surface, 174 Outer plane, 175a, 175b Side surface, 178 Protruding part, 179 Contact surface, 181 Pigtail, 182 Adhering part, 183 Exposed part, 271 Brush, 273 Inclined surface, 373 Inclined surface, 472 Inner plane, 572 Curved surface, 673 Curved surface, 773 Curved surface, 872 First plane , 873 2nd plane, 877 middle part, 971 brush, 973 inclination

Claims (6)

A spring fixing portion that fixes a central portion of the winding spring; and a brush holding portion that holds the brush in a slidable manner in the radial direction of the rotating electrical machine. In the brush device of the rotating electrical machine that is pressed toward the commutator of the rotating electrical machine,
The brush has, on the opposite side of the contact surface with the commutator, an inclined surface that is inclined so that the distance from the rotation axis center of the rotating electrical machine becomes longer as the distance from the central portion of the winding spring increases.
In the initial state where the brush is not worn, the contact point of the end of the winding spring with respect to the inclined surface in the use limit state where the brush is worn by a predetermined amount is more than that of any part of the winding spring. A brush device for a rotating electrical machine in which the inclined surface is formed so as to be positioned radially outward. A spring fixing portion that fixes a central portion of the winding spring; and a brush holding portion that holds the brush in a slidable manner in the radial direction of the rotating electrical machine. In the brush device of the rotating electrical machine that is pressed toward the commutator of the rotating electrical machine,
The brush has, on the opposite side of the contact surface with the commutator, an inclined surface that is inclined so that the distance from the rotation axis center of the rotating electrical machine becomes longer as the distance from the central portion of the winding spring increases.
In the initial state where the brush is not worn, the winding spring is located radially outside the rotating electrical machine with respect to a straight line connecting a contact point of the end portion of the winding spring on the inclined surface and a center portion of the winding spring. A brush device for a rotating electrical machine in which the inclined surface is formed such that the end portion of the rotating device comes into contact with the inclined surface. In the brush apparatus of the rotary electric machine according to claim 1 or 2,
The brush has at least a first surface and a second surface inclined with respect to the first surface on the opposite side of the contact surface with the commutator,
The second surface is the inclined surface;
In the initial state, the end of the winding spring is in contact with each of the first surface and the second surface,
In the use limit state in which the brush is worn by a predetermined amount, the end of the winding spring is in contact with the second surface and is not in contact with the first surface. The brush apparatus of the rotary electric machine in which 2 surfaces are formed. In the brush apparatus of the rotary electric machine according to claim 1 or 2,
The side of the brush is connected to a pigtail having a fixed portion fixed in the brush and an exposed portion extending from the fixed portion to the outside of the brush,
In the initial state, a boundary cross section between the fixing portion and the exposed portion in the pigtail is located on a virtual plane orthogonal to the length direction of the brush passing through a contact point of the end of the winding spring with respect to the inclined surface. The rotating electrical brush device. The brush device for a rotating electrical machine according to claim 4,
The boundary cross section between the fixed portion and the exposed portion in the pigtail is in a radial direction of the rotating electrical machine more than a contact point of an end portion of the winding spring with respect to the inclined surface in a use limit state where the brush is worn by a predetermined amount. A brush device for a rotating electrical machine located inside. A brush device for a rotating electrical machine according to claim 1 or 2,
A rotor including the commutator;
A stator disposed on the outer peripheral side of the rotor;
A cylindrical yoke for holding the stator;
A bottomed cylindrical bracket to which the spring fixing portion and the brush holding portion are fixed;
A rotating electrical machine in which an opening of the bracket and an opening of one end of the yoke are connected.

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