JP3610643B2 - Rotating electric machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a yoke for a rotating electrical machine that is employed as a stator of a rotating electrical machine, and more particularly to a rotating electrical machine that is employed in a starter motor or the like under high vibration conditions in a vehicle or the like and uses a permanent magnet as a field magnetic pole. About York.
[0002]
[Prior art]
In recent years, in order to realize a reduction in weight and cost of a rotating electrical machine, a rotating electrical machine in which a permanent magnet stator is adopted instead of a conventional winding stator is becoming widespread. The configuration and assembly configuration of the yoke 50 in such a rotating electric machine are shown in FIGS. The yoke 50 constitutes an outer shell of the rotating electric machine, and is constituted by a cylindrical yoke 11 formed in a cylindrical shape and a lid portion 14 that covers both ends of the cylindrical yoke 11. In the rotating electrical machine that employs permanent magnets for the stator, a plurality of permanent magnets 12 are disposed on the inner peripheral surface of the cylindrical yoke 11. In the rotating electrical machine shown in FIG. 7, the lid portions 14 provided at both ends of the cylindrical yoke 11 are formed to be larger than the outer diameter of the cylindrical yoke 11 by a diameter of a through bolt described later. The lid portions 14 at both ends of the cylindrical yoke 11 are formed by a plurality of through bolts 13 at the flange portion 15 protruding outside the outer diameter of the cylindrical yoke 11 by the diameter of the through bolt 13. Fastened to both ends. Further, in the rotating electrical machine shown in FIG. 8, the diameter of the lid portion 14 is formed substantially equal to the outer diameter of the cylindrical yoke 11. The lid portions 14 at both ends of the cylindrical yoke 14 are fastened and fixed to both end portions of the cylindrical yoke 11 with through bolts 13 passing through the cylindrical yoke 11.
[0003]
As the permanent magnet 12 employed in the rotating electrical machine in FIGS. 5 and 6, a high-performance ferrite magnet or the like that is lower in cost than a wound stator is employed. This ferrite magnet is characterized by a relatively low residual magnetic flux density of 3000 to 5000 gauss and a small amount of magnetic flux. Therefore, when such a permanent magnet 12 is employed in a stator of a rotating electrical machine, the metal cylindrical yoke 11 that concentrates the magnetic field is made thinner than in the case where a winding stator is employed. Is possible. As described above, the cylindrical yoke 11 formed in a cylindrical shape can be thinned, so that the weight reduction and cost reduction of the rotating electrical machine can be realized.
[0004]
Furthermore, a hollow extending in the axial direction is formed in the inner circumference or outer circumference of the cylindrical portion of the yoke (yoke) in the Nihon Denshoku Electric Technical Report 29-232, and a through bolt is passed through this hollow portion. In this way, it is possible to suppress the innermost diameter and outermost diameter of the through bolt that protrudes into and out of the yoke.
[0005]
[Problems to be solved by the invention]
However, the former rotating electrical machine according to the conventional example may be employed in a starter motor of a vehicle, for example, and may be disposed under high vibration conditions. In such a case, the thin cylindrical yoke 11 as described above may have low rigidity and resonate with external vibrations of the engine or the like. In this case, it is conceivable that each part in the rotating electrical machine such as the looseness fixed by the through bolt 13 is damaged, or abnormal wear occurs between the parts. These affect the life of the rotating electrical machine or starter. Therefore, in order to overcome these situations, for example, the thickness of the cylindrical yoke 11 can be increased, or the number of through-bolts 13 that are tightening and fixing the lid portion 14 can be increased. There has been a problem that the rotating electric machine is reduced in weight and cost.
[0006]
Further, as described above, when the cylindrical yoke 11 and the lid portion 14 are fastened and fixed with the through bolts 13 within the inner circumference of the cylindrical yoke 11 in the flange portion 15 or the lid portion 14, the lid portion 14. A bending moment is applied to the end of the cylindrical yoke 11 as a fulcrum. At this time, if the fastening force of the through bolt 13 is increased to some extent, the lid portion 14 may be deformed. For example, in the rotating electrical machine shown in FIG. 5, a bending moment is applied in the α1 direction as shown in FIG. 7, and the lid portion 14 is deformed in the α2 direction. In the rotating electrical machine yoke shown in FIG. 6, a bending moment is applied in the β1 direction as shown in FIG. 8, and the lid portion 14 is deformed in the β2 direction. Therefore, if the lid 14 is made of a highly rigid material to increase the rigidity of the lid 14, the cylindrical yoke 13 formed of a thin steel plate or the like having low rigidity may be distorted. As described above, in order to increase the rigidity of the lid portion 14, the use of a highly rigid material or the increase in the thickness is similar to the case of the cylindrical yoke 11 described above. Needless to say, this will hinder costs.
[0007]
In addition, the through bolt of the rotating electrical machine according to the latter conventional example has a part of its cross section entering the virtual yoke cylindrical portion (recess), but until most of the cross section including the center of the shaft is accommodated. Not reached. That is, the fastening force that acts on the bracket (lid portion) by the through bolt is deviated from the virtual cylindrical portion of the yoke with which the bracket is in contact. Therefore, as described above, a moment acts on the through bolt receiving surface of the bracket in the axial direction, and the bracket is distorted. This means that when the bracket is set to ground, the starter motor circuit cannot be connected, and when the bracket supports the rotation of the armature, the armature thrust becomes clogged, making it impossible to rotate. There was a risk of becoming.
[0008]
Thus, in a rotating electrical machine that uses a thin steel plate for the cylindrical yoke 11 to achieve weight reduction and cost reduction, the rigidity of the cylindrical yoke 11 is ensured, and the through-bolt tightening force is sufficiently exhibited when the yoke is assembled. It was very difficult to do.
Accordingly, an object of the present invention is to provide a yoke for a rotating electrical machine that realizes weight reduction and cost reduction and that can ensure sufficient durability even when employed in a high vibration environment.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a rotating electrical machine according to the present invention has a built-in permanent magnet forming a field magnetic pole and is formed in a substantially cylindrical shape, and an end of the cylindrical portion of the rotating electrical machine yoke. disposed parts, the abutting lid portion on the end surface of the cylindrical portion, and pressed from the axially outer side of the lid part, fastened to the lid portion to the yoke, provided with through-bolts for securing the through-bolts A part of the diameter of the yoke is set so as to be hidden in the concave portion, and the cylindrical portion of the yoke is formed with a concave portion recessed along the axial direction from the inner peripheral side or the outer peripheral side. A center to which the fastening force is applied is set between a virtual outermost diameter and a virtual innermost diameter of the cylindrical portion in the concave portion, and the cylindrical portion and the lid portion are fastened and fixed , and
It is mounted on a vehicle and used as a drive motor for a starter that starts an engine .
[0010]
Further, the recess in the cylindrical portion of the yoke for the rotating electrical machine has a substantially semicircular shape, the through bolt has a circular cross section, and the through bolt is guided by the substantially semicircular recess so that the through bolt The rotating electrical machine according to claim 1, wherein the axial center of the rotating electrical machine is located between a virtual outermost diameter and a virtual outermost diameter of the cylindrical portion. The concave portion of the cylindrical portion of the yoke for a rotating electrical machine is substantially semicircular, and has a uniform protruding portion along the axial direction in the opening of the concave portion. You may make it employ | adopt the yoke for rotary electric machines as described.
[0011]
Further, the cylindrical portion is formed with a plurality of recesses, and the permanent magnet that contacts between the pair of recesses is disposed on an inner peripheral surface of the cylindrical portion. You may make it employ | adopt the yoke for rotary electric machines of Claim 2 or Claim 3 .
[0012]
Further, the recess in the cylindrical portion of the rotating electrical machine yoke is substantially semicircular, the through bolt has a circular cross section, and the through bolt is guided by the substantially semicircular recess so that the through Only a part of the diameter of the bolt is set to be hidden in the recess, and the axial center of the through bolt is located between the virtual extension outer diameter and the virtual extension inner diameter of the cylindrical part. The rotating electrical machine according to claim 5 may be adopted.
[0013]
[Action and effect]
The operation of the rotary electric machine yoke according to the present invention configured as described above will be described below.
As described above, the cylindrical portion of the yoke is formed with a concave portion that is recessed in the axial direction from the inner peripheral side or the outer peripheral side, and this concave portion serves as a rib. Therefore, even when the cylindrical portion is formed of a thin steel plate or the like, it can have sufficient rigidity. In other words, the assembly of the rotating electrical machine yoke and the lid is performed by the through bolt in the recess. The center that exerts the tightening force of the through bolt is formed by the cylindrical portion and the concave portion of the yoke, and is set between the virtual innermost diameter and the virtual outermost diameter of the cylindrical portion on the end surface with which the lid portion abuts. By doing so, the compressive force applied to the cylindrical part at the time of fastening with a through bolt is applied to the virtual cylindrical cross section of the cylindrical part. In other words, the moment generated in the radial direction of the cylindrical yoke and the axial direction of the lid portion can be suppressed as much as possible by the tightening force of the through bolt, and the deformation of the cylindrical yoke and the lid portion can be prevented by the tightening force. it can. As a result, the cylindrical yoke for the rotating electrical machine and the lid can be securely tightened with the through bolts.
[0014]
Here, the imaginary outermost diameter and the imaginary innermost diameter indicate the diameter of a circle formed by connecting the local maximum points or the local minimum points of the radii on the axial end surface of the yoke cylindrical portion with which the lid portion abuts, The virtual cylindrical cross section means between the two.
Also, by forming the concave portion in the cylindrical portion of the yoke in a semicircular shape, the outer diameter of the through bolt is guided along the concave portion, so that it is easy to insert the male screw into the female screw portion when assembling the through bolt, There is no need to provide a large guide surface at the opening of the female screw portion, and a rotating electrical machine that can be easily assembled and processed can be configured.
[0015]
In addition, when a uniform protrusion is formed along the axial direction at the recess opening of the yoke cylindrical portion, the virtual outermost diameter or virtual innermost diameter of the yoke cylindrical portion expands toward the outer diameter or inner diameter side, respectively. The range in which the axis of the bolt can be arranged can be expanded, and the degree of design freedom can be increased. Further, if the through-bolt head pressing surface is also disposed within this range, a more stable fastening force can be obtained.
[0016]
When the permanent magnet is mounted, the concave portion or the projecting portion that protrudes to the inner circumference of the yoke is brought into contact with the circumferential end of the magnet to achieve this positioning, and the assembling property is improved.
Furthermore, since the starter for starting the engine is mounted on the engine main body or a part attached to the engine, the engine is susceptible to vibration of the engine. If the rotating electrical machine of the present invention is used as a starter motor, the yoke is formed of a thin steel plate. However, it is possible to supply a starter using a permanent magnet field that can secure sufficient rigidity and sufficiently withstand vibrations received from the engine.
[0017]
Further, the center that exerts the fastening force of the through bolt is formed by the cylindrical portion and the concave portion of the yoke, and is between the virtual extension inner diameter and the virtual extension outer diameter of the cylindrical portion on the end surface with which the lid portion abuts. By being set, the compressive force applied to the cylindrical portion at the time of fastening by the through bolt is surely applied to the cylindrical cross section of the cylindrical portion. In other words, the moment generated in the radial direction of the cylindrical yoke and the axial direction of the lid portion can be suppressed as much as possible by the tightening force of the through bolt, and the deformation of the cylindrical yoke and the lid portion can be prevented by the tightening force. it can. As a result, the cylindrical yoke for the rotating electrical machine and the lid can be further securely tightened with the through bolts.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a circumferential sectional view of a rotating electrical machine (excluding an armature) according to the present invention, and FIG. 2 is an axial sectional view.
As shown in FIGS. 1 and 2, the rotating electrical machine 1 includes a cylindrical yoke 2 formed of a cylindrical metal material, and lid portions 5 that cover both ends of the cylindrical yoke 2.
[0019]
A plurality of recesses 4 are formed on the outer surface of the cylindrical yoke 2 in the central axis direction of the cylindrical yoke 2. The concave portion 4 is formed in a substantially semicircular shape toward the radially inner peripheral side of the cylindrical yoke 2. A permanent magnet 6 as a field magnetic pole of a rotating electrical machine is fixed to the inner peripheral surface of the cylindrical yoke 2 with an adhesive or the like. The permanent magnet is positioned by a convex portion 4 a on the inner peripheral surface of the cylindrical yoke 2, which is the back side of the concave portion 4. That is, the permanent magnet 6 is fixed after being aligned with the base portion 4b of the convex portion 4a. This improves the assembling property of the rotating electrical machine.
[0020]
The lid 5 is covered so as to cover both ends of the cylindrical yoke 2. The lid 5 is formed to be larger by a predetermined value than the diameter of the cylindrical yoke 2. That is, the lid 5 has a diameter that allows a through-hole through which a through bolt 3 to be described later penetrates.
The two lid portions 5 formed at both ends of the cylindrical yoke 2 and the cylindrical yoke 2 are fastened and fixed in the central axis direction of the cylindrical yoke 2 by a through bolt 3. The through-bolt 3 is disposed at a position where the axial center 3 a of the through-bolt 3 falls between the virtual outermost diameter d 1 and the virtual extended outer diameter D (virtual outermost diameter) of the cylindrical yoke 2. That is, the center 3a of the fastening force of the through bolt 3 has the same diameter as the portion of the cylindrical yoke 2 where the outer diameter is D. Furthermore, in this embodiment, the center of the through-bolt 3 is arranged at a position where the axial center 3a of the through-bolt 3 fits between the virtual extension inner diameter d2 and the virtual extension outer diameter D of the cylindrical yoke 2. .
[0021]
FIG. 4 shows an example of a vehicle starter 100 to which the rotating electrical machine configured as described above is applied. The starter 100 includes a starter motor 110, a housing 120 that forms lids disposed at both ends of a yoke 111 of the starter motor 100, and an end frame 130. A magnet 112 is fixed to the inner circumference of the yoke 111, and an armature 113 is rotatably arranged on the inner circumference of the magnet 112. Further, the yoke 111 is formed with recesses 111a corresponding to the plurality of recesses. In the housing 120, a pinion (not shown) that meshes with the ring gear of the engine is provided, and a female screw portion 121 into which the male screw portion 3 b at the tip of the through bolt 3 is screwed is formed. A magnet switch (not shown) that energizes the starter motor 110 is housed in the end frame 130. Further, the end frame 130 is formed with a through hole 131 into which the through bolt 3 is inserted and in which the head 3c comes into contact. Reference numeral 140 denotes a brush holding plate that holds a brush (not shown) for energizing the armature 113 of the starter motor 110, and is sandwiched between the yoke 111 and the end frame 130. Reference numeral 150 denotes a motor partition that is sandwiched between the yoke 111 and the housing 120.
[0022]
At both ends of the yoke 111, an end frame 130 and a housing 120 are disposed via a brush holding plate 140 and a motor partition 150, respectively. Then, the male screw portion 3 b at the tip of the through bolt 3 is passed through the through hole 131 of the end frame 130 and screwed into the female screw portion 121 of the housing 120, so that the end frame 130 and the housing 120 are firmly attached to the yoke 111. Fix it.
[0023]
Since such a starter 100 is disposed in the immediate vicinity of the engine of the vehicle, it directly receives engine vibration and the like. Therefore, the yoke of a rotating electrical machine employed in such an environment is heavily loaded by vibration, and requires a certain degree of rigidity and a fixing force during assembly.
The effects of the rotating electrical machine 1 configured as described above will be described below.
[0024]
As described above, the concave portion 4 is uniformly formed in the central axis direction on the outer periphery of the cylindrical yoke 2. Since the concave portion 4 serves as a rib in the cylindrical yoke 2, sufficient rigidity can be secured even in the cylindrical yoke 2 formed of a thin steel plate.
In addition, the through-bolt 3 is set such that the shaft center 3a is between the virtual outermost diameter d1 of the cylindrical yoke 2 in the recess 4 and the virtual extended outer diameter D (virtual outermost diameter). Accordingly, when the through bolt 3 is tightened, the center of the tightening force is located between the innermost diameter and the outermost diameter of the yoke, so that almost no bending moment applied to the lid 5 can be eliminated. That is, the cylindrical yoke 2 simply receives a compressive force in the direction of the central axis by fastening the through bolt 3. Therefore, it is not necessary to use a material having a particularly high rigidity for the lid 5 or increase the thickness. For this reason, the lid 5 and the cylindrical yoke 2 can be fastened and fixed by receiving the fastening force of the through-bolts 3 in the direction and part where the highest rigidity of the cylindrical yoke 2 can be exhibited. Therefore, the through bolt 3 can be fastened and fixed with a sufficiently strong load.
[0025]
Furthermore, by setting the axial center 3a of the through bolt 3 between the virtual extension inner diameter d2 and the virtual extension outer diameter D of the cylindrical yoke 2 in the recess 4, the center of the tightening force when the through bolt 3 is tightened. Is located in the cylindrical cross section between the inner diameter and the outer diameter of the yoke, the bending moment applied to the lid portion 5 can be further eliminated, and the yoke 2 capable of exhibiting the highest rigidity in the cylindrical yoke 2. The lid 5 and the cylindrical yoke 2 can be fastened and fixed by receiving the fastening force of the through-bolts 3 on the end face.
[0026]
As an accompanying effect, a part of the diameter of the through-bolt 3 is set so as to be hidden in the recess 4, so that the protrusion from the outer periphery of the cylindrical yoke 2 is reduced, and the size of the rotating electrical machine is reduced. Can also be realized. Further, it goes without saying that the concave portion 4 also serves as a positioning mechanism for the through bolt 3 at the time of fastening with the through bolt 3 and contributes to an improvement in assembling.
[0027]
In this way, in the yoke of the rotating electrical machine according to the present invention, it is possible to use a thin steel plate for the cylindrical yoke and to fasten and fix each yoke sufficiently firmly. It is possible to achieve both vibration resistance. That is, even when a rotating electrical machine that achieves weight reduction and cost reduction is used in a high vibration environment, a sufficiently reliable rotating electrical machine can be provided.
[0028]
In addition, as shown in FIG. 3, you may make it form the protrusion part 4d which protruded around the said recessed part 4 in the uniform height and radial direction from the outer periphery of the cylindrical yoke 2. As shown in FIG. When the yokes are fastened and fixed by the through bolts 3, the head pressing surface 3 c of the through bolt 3 holds down not only the extension of the end of the cylindrical yoke 2 but also the extension of the projection 4 d. The cylindrical yoke can withstand the higher fastening force of the through bolt 3. That is, even if it does in this way, it is possible to raise the effect which is not inferior to the said Example.
[0029]
In this embodiment, the axial center 3a of the through-bolt 3 is located between the virtual outermost diameter d1 of the cylindrical yoke 2 and the virtual outermost diameter D1 (in contact with the outermost diameter of the protruding portion 4d). Placed in. Further, the axial center 3a of the through-bolt 3 is arranged at a position that fits between the virtual extension inner diameter d2 and the virtual extension outer diameter D2 of the cylindrical yoke 2, thereby exhibiting the highest rigidity in the cylindrical yoke 2. The lid 5 and the cylindrical yoke 2 can be fastened and fixed by receiving the fastening force of the through bolt 3 on the end face of the yoke 2 that can be used.
[0030]
In the above description of the embodiment, an example in which the outer periphery of the cylindrical yoke 2 has a recess recessed toward the inner diameter side is shown, but the inner periphery of the cylindrical yoke 2 is recessed toward the outer diameter side (projected toward the outer periphery side). ) Needless to say, the same effect can be obtained with a cylindrical yoke having a concave portion (convex portion). Moreover, although the cover part 5 demonstrated the example covered to the both end surfaces of the cylindrical yoke 2 (illustration shows only one side), the cover part is provided only in one side and the internal thread which fastens a through bolt is cylindrical, for example A flange may be provided on the yoke, a female screw may be formed therein, and the lid 5 (for example, the end frame 130) may be directly fastened to the cylindrical yoke 2.
[Brief description of the drawings]
FIG. 1 is a circumferential sectional view of a yoke of a rotating electrical machine according to the present invention.
FIG. 2 is an axial sectional view of a yoke of a rotating electrical machine according to the present invention.
FIG. 3 is a sectional view showing another embodiment of the yoke of the rotating electrical machine according to the present invention.
FIG. 4 is a cross-sectional plan view of a part of the starter when the yoke of the rotating electrical machine according to the present invention is employed in a vehicle starter.
FIG. 5 is a circumferential sectional view showing a yoke of a conventional rotating electric machine.
FIG. 6 is a circumferential sectional view showing a yoke of a conventional rotating electric machine.
FIG. 7 is a partial cross-sectional plan view showing an action when fastening and fixing a yoke of a conventional rotating electric machine.
FIG. 8 is a partial cross-sectional plan view showing an action when fastening and fixing a yoke of a conventional rotating electric machine.
[Explanation of symbols]
2 Cylindrical yoke 3 Through bolt 3a Shaft bolt shaft center 4 Recess 5 Lid member 100 Starter 110 Starter motor 111 Yoke 112 Magnet 111a Recess 120 Housing 130 End frame

Claims (5)

Built-in permanent magnets that form field magnetic poles, and a substantially cylindrical yoke for a rotating electrical machine,
A lid that is disposed at the end of the cylindrical portion of the yoke for the rotating electrical machine and that contacts the end surface of the cylindrical portion;
A presser bolt for pressing from the outside in the axial direction of the lid, fastening the lid to the yoke, and fixing the lid,
The cylindrical portion of the yoke is formed with a recess recessed along the axial direction from the inner peripheral side or the outer peripheral side,
Only a part of the diameter of the through bolt is set to be hidden in the recess,
The axial center of the through-bolt is set between a virtual outermost diameter and a virtual innermost diameter of the cylindrical part end face in the concave part, and the cylindrical part and the lid part are fastened and fixed ; and
A rotating electrical machine that is mounted on a vehicle and used as a drive motor for a starter that starts an engine . The concave portion of the cylindrical portion of the yoke for the rotating electrical machine is substantially semicircular, the through bolt is circular in cross section, and the through bolt is guided by the substantially semicircular concave portion, thereby The rotating electrical machine according to claim 1, wherein the center is located between a virtual outermost diameter and a virtual innermost diameter of the cylindrical portion. The concave portion in the cylindrical portion of the yoke for a rotating electrical machine is substantially semicircular, and has a uniform protruding portion along the axial direction in the opening of the concave portion. Yoke for rotating electrical machines. 4. A plurality of concave portions are formed in the cylindrical portion, and the permanent magnet that contacts between the pair of concave portions is disposed on an inner peripheral surface of the cylindrical portion. A yoke for a rotating electrical machine according to any one of the above. Built-in permanent magnets that form field magnetic poles, and a substantially cylindrical yoke for a rotating electrical machine,
A lid that is disposed at the end of the cylindrical portion of the yoke for the rotating electrical machine and that contacts the end surface of the cylindrical portion;
A presser bolt for pressing from the outside in the axial direction of the lid, fastening the lid to the yoke, and fixing the lid,
The cylindrical portion of the yoke is formed with a recess recessed along the axial direction from the inner peripheral side or the outer peripheral side,
Only a part of the diameter of the through bolt is set to be hidden in the recess,
The rotating electrical machine characterized in that an axial center of the through bolt is set between a virtual outermost diameter and a virtual outermost diameter of the cylindrical portion, and the cylindrical portion and the lid portion are fastened and fixed.

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