JP2002199660A - Fixing structure of magnet for magnetic sensor mounted on rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a magnet for magnetic sensor mounted on a rotor securely and easily. SOLUTION: In a fixing structure of magnet for magnetic sensor mounted on rotor, a sensor magnet 8 is fitted into a boss part 2 of a rotor yoke 3, a reduced diameter part 7d surrounding the sensor magnet 8 in a press-fitted state and a L-shaped bended part 7c to prevent the magnet 8 form coming out in the axial direction are mounted on an inner circumference wall part 7b of a magnet cover 7 fixing a magnet 9 for field placed on a surrounding wall part of the rotor yoke 3, the magnet 8 is sandwiched between an outward flange part 2 of the boss part 2 and the bended part 7c and also the magnet 8 is fixed by the press-fitted state to the reduced diameter part 7d. Accordingly, the magnet 9 and the magnet 8 can be fixed by the magnet cover 7 made of one part, it becomes easy to assemble because a parts count and number of man-hours necessary to assemble the magnet 8 can be reduced and also it becomes possible to securely fix the magnet 8 because the magnet 8 is fixed by the magnet cover 7 combined to the rotor in one-piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for fixing a magnet for a magnetic sensor to a rotor.

[0002]

2. Description of the Related Art Conventionally, in brushless motors and the like,
FIG. 5 shows an example in which a rotor is provided with a magnet for a magnetic sensor for detecting a position (angle). In the figure, a rotor yoke 21 forming a bottomed cylindrical body is shown.
A rotating shaft coupling boss 22 is integrally provided at the center of the bottom of the rotor yoke, and is provided on the inner peripheral surface of the peripheral wall 21a of the rotor yoke 21 in the circumferential direction so as to correspond to the exciting coil of the stator (not shown). A plurality of arc-shaped magnets 23 arranged at equal pitches are provided. Those magnets 23
Is held by a cylindrical magnet cover 24 integrally joined to the rotor yoke 21 by, for example, embossing 21a.

[0003] A single annular magnet 25 for a magnetic sensor is assembled to the boss 22. In the fixing structure, for example, the magnetic sensor magnet 25 having the above-mentioned annular shape is pressed into the inner peripheral surface of the sensor magnet cover 26 in the boss portion 22, and the magnetic sensor magnet 25 is inserted into the cylindrical surface portion 22 a of the boss portion 22. Magnet 25
Is to be inserted. Further, in order to securely fix the sensor magnet cover against acceleration / deceleration rotation, a radially inward end of the sensor magnet cover 26 is formed in an outer peripheral groove 22 b provided in the boss portion 22.
To prevent the sensor magnet cover 26 from coming off, and the magnet 25 for the magnetic sensor is fixed.

[0004]

However, in order to press-fit the sensor magnet cover 26 into which the magnet 25 for the magnetic sensor is press-fitted into the boss portion 22 as described above, it is necessary to ensure its roundness and press-fit strength. The cylindrical surface portion 22a and the outer peripheral groove 22b of the boss portion 22 to be mated are cut. In addition, there is a problem that the assembling becomes complicated, for example, the above-mentioned dedicated sensor magnet cover 26 is required to more securely fix the inserted magnetic sensor magnet 25.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to make it possible to securely and easily fix a magnet for a magnetic sensor provided on a rotor, a magnet for generating a magnetic field according to the present invention is provided. A fixing structure of the magnet for the magnetic sensor to the rotor for fixing the magnet for the magnetic sensor to the rotor provided with the magnet for holding the magnetic field generating magnet and integrally connected to the rotor. The magnet for the magnetic sensor was fixed in a press-fit state by a part of the magnet cover.

According to this, the magnet for generating the field and the magnet for the magnetic sensor can be fixed by the magnet cover made of one part, and the number of parts and the number of assembling steps are reduced as compared with the case where separate covers are used. I can do it.

The magnet for the magnetic sensor is formed in an annular shape to be fitted on a boss provided coaxially with the rotor, and a part of the magnet cover is formed by the magnet for the magnetic sensor. The outer peripheral surface of the boss portion is fixed to the boss portion by fixing the sensor magnet cover into which the annular magnetic sensor magnet is press-fitted into the boss portion. This eliminates the need for the steps of cutting and crimping the cover dedicated to the magnet for the magnetic sensor to the boss portion and engaging the same.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to specific examples shown in the accompanying drawings.

FIG. 1 shows an engine A to which the present invention is applied.
It is a sectional side view of a CG starter. This ACG starter
It is particularly suitable for small motorcycles, is coaxially mounted on the crankshaft 1 of the engine, and functions as a starter motor and a generator. This ACG starter is fixed to a rotor yoke 3 as a rotor having a boss 2 integrally provided so as to protrude coaxially from the center of the bottom of the bottomed cylindrical body, and to an engine end face (not shown). And a stator 4. The boss 2
Are fitted and assembled to the crankshaft 1 so that the rotor yoke 3 rotates coaxially and integrally with the crankshaft 1.

[0010] A plurality of core teeth 4a are radially provided on the stator 4, and a coil 5 is wound around each core tooth 4a. Note that each coil 5 may have a three-phase winding structure. A plurality of magnetic field generating magnets 6 are arranged in the circumferential direction on the inner peripheral surface of the peripheral wall of the rotor yoke 3 so as to correspond to the respective core teeth 4a, and are fixed by a magnet cover 7.

The ACG starter is configured as a brushless motor, and has an annular sensor magnet 8 for a magnetic sensor on the outer peripheral surface of the boss portion 2 of the rotor yoke 3 in order to detect the position (angle) of the rotor 3. Is attached. A Hall IC 9 for detecting a change in the position of the magnetic pole of the sensor magnet 8 is held and arranged in a case 10 fixed to an appropriate position of the stator 4. Since the ACG starter has a three-phase brushless motor structure, three Hall ICs 9 are provided at a predetermined angular pitch in the circumferential direction corresponding to the U, V, and W phases.

The U, V, and W phase lead wires of the coil 5 and the lead wires of each Hall IC 9 are bundled by a cable holder 11 and guided to an external circuit. On the outer peripheral surface of the peripheral wall portion of the rotor yoke 3, a reluctor 12, which is stamped out from the radial inside by press working, is provided over a predetermined angular range in the circumferential direction for detecting an ignition timing position.

Next, the boss 2 of the sensor magnet 8
The fixing structure for is shown below with reference to FIG. As shown in FIG. 2, the boss 2 of the rotor yoke 3
After the sensor magnet 8 is fitted into the magnet cover 7 and the magnets 6 each having an arc shape are inserted and arranged on the inner peripheral surface of the peripheral wall of the rotor yoke 3, the magnet cover 7 is inserted.
Into the rotor yoke 3.

The rotor yoke 3 is provided on the magnet cover 7.
As shown in FIG. 3 showing a state in which the magnet 6 is mounted inside, an outer peripheral wall portion 7 a for elastically pressing the magnet 6 radially outwardly against the peripheral wall portion of the rotor yoke 3.
And an inner peripheral wall portion 7 surrounding the sensor magnet 8 and resiliently pressing the sensor magnet 8 radially inward against the boss portion 2.
b are formed. And the magnet cover 7
Is integrally connected to the rotor yoke 7 by inserting the embossment 3a provided on the rotor yoke 7 into a hole 7d provided on a bottom wall 7c between the two wall portions 7a and 7b and caulking.

The outer peripheral wall 7a of the magnet cover 7
Is bent radially outward in an L-shape, and after the magnet cover 7 is assembled to the rotor yoke 3, the outer wall 7 a of the magnet cover 7 is attached to the bottom wall 7 c on the side of the magnet 6.
The magnet 6 is positioned and fixed in the axial direction by performing plastic deformation processing so that the diameter of the magnet 6 is larger than the diameter of the inner peripheral surface of the magnet 6. In the circumferential direction, the magnet 6 is positioned and fixed by the pressing force of the magnet cover 7 for pressing the magnet 6 against the outer peripheral wall 7a and the resulting contact resistance between the magnet 6 and the outer peripheral wall 7a.

The sensor magnet 8 is loosely fitted in a shelf 2a formed on the base end side of the boss 2 (on the side of the bottom wall 7c of the magnet cover 7), and an outward flange 2b formed on the boss 2. And positioned. A radially inwardly bent L-shaped bent portion 7e is formed at the tip of the inner peripheral wall portion 7b of the magnet cover 7, and a sensor magnet 8 is disposed between the outward flange portion 2b and the L-shaped bent portion 7e. Are sandwiched and held.

On the side of the L-shaped bent portion 7e of the inner peripheral wall portion 7b, as is well shown in FIG. 4, in the assembled state of FIG. A reduced diameter portion 7f is provided. The magnet cover 7 is integrally connected to the rotor yoke 3 by inserting the embossment 3a of the rotor yoke 3 into the hole 7d and caulking as described above. Thus, the sensor magnet 8 is fixed together by the magnet cover 7 for fixing the magnet 6.

Accordingly, the outer peripheral surface of the mating boss portion is cut to secure the roundness and the press-fitting strength associated with the insertion of the magnet for the magnetic sensor into the boss portion as described in the conventional example, Man-hours such as caulking the boss of the magnet cover are not required. In addition, since the magnet 6 and the sensor magnet 8 are fixed by the magnet cover 7 made of one part, the number of parts and the number of assembling steps can be reduced as compared with the case where separate covers are used.
Also, when the present magnet cover 7 is punched from a single thin plate material, the center part is cut off in the case of a conventional magnet-dedicated cover. The portion which has been used can be effectively used as the inner peripheral wall portion 7b, the material cost does not increase, and the cost reduction is promoted because the sensor magnet dedicated cover is no longer required. Further, since the magnet cover 7 is coupled to the rotor yoke 3 by caulking the embossments 3a, the sensor magnet 8 is securely fixed.

In this embodiment, the structure for fixing the Hall IC of the ACG starter is described. However, the present invention is not limited to this, and is applicable to a structure using a magnet for detecting the position of the rotor.

[0020]

As described above, according to the present invention, the magnet for generating the field and the magnet for the magnetic sensor can be fixed by the magnet cover made of one component. Since the number of points and the number of assembling steps can be reduced, the assembling becomes easy, and since the magnet is fixed by the magnet cover integrally connected to the rotor, the magnet for the magnetic sensor can be securely fixed.

Further, an annular magnet dedicated to magnetism is fitted on a boss provided coaxially with the rotor, and is surrounded by a part of the magnet cover in a press-fit state, thereby providing an annular magnet for a magnetic sensor. In order to secure the roundness and the press-fitting strength associated with the insertion into the boss, the outer peripheral surface of the mating boss is This eliminates the need for man-hours such as caulking and engaging the cover dedicated to the magnet for the magnetic sensor with the boss portion, and also eliminates the damage caused by press fitting.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an ACG starter for an engine to which the present invention is applied.

FIG. 2 is an exploded side sectional view of a rotor yoke.

FIG. 3 is a front view of a magnet cover.

FIG. 4 is an enlarged sectional view of a main part showing a fixed state of the sensor magnet.

FIG. 5 is a side sectional view showing a fixing structure of a conventional magnet for a magnetic sensor.

[Explanation of symbols]

Reference Signs List 1 crankshaft 2 boss portion, 2a shelf portion, 2b outward flange portion 3 rotor yoke 4 stator 5 coil 6 magnet for generating magnetic field 7 magnet cover, 7a outer peripheral wall portion, 7b inner peripheral wall portion, 7c bottom wall portion 7d hole, 7e L Character-shaped bent part, 7f reduced diameter part 8 Sensor magnet 9 Hall IC

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 21/22 H02K 29/00 Z 29/00 11/00 C (72) Inventor Yasuhiro Takebe Kiryu, Gunma Prefecture 1-2681, Hirosawa-cho, Ichiba, Japan Mitsuba Co., Ltd. (72) Inventor Toshiyuki Kobayashi 1-2681, Hirosawa-cho, Kiryu-shi, Gunma F-term in Mitsuba Co., Ltd. 5H002 AA07 AB05 AB07 AC06 AC08 AE08 5H019 AA10 BB05 BB10 BB15 BB19 BB22 BB24 CC03 CC08 DD01 EE09 EE11 EE14 5H611 BB07 PP05 QQ01 QQ03 RR02 TT01 UA01 UB02 5H621 BB10 GA01 GA04 GA17 GB10 GB14 HH01 HH02 HH06 HH08 JK02 JK04 JK07 JK14 JK15 5H622 CA01 PP05

Claims (2)

[Claims] 1. A structure for fixing a magnet for a magnetic sensor to a rotor for fixing the magnet for a magnetic sensor to a rotor provided with a magnet for generating a magnetic field, the magnet holding the magnet for generating a magnetic field; A structure for fixing a magnet for a magnetic sensor to a rotor, wherein the magnet for a magnetic sensor is fixed in a press-fit state by a part of a magnet cover integrally connected to the rotor. 2. The magnet for a magnetic sensor, wherein the magnet for the magnetic sensor is formed in an annular shape to be fitted to a boss provided coaxially with the rotor, and a part of the magnet cover is formed by the magnet for the magnetic sensor. 2. The structure for fixing a magnet for a magnetic sensor to a rotor according to claim 1, wherein the magnet is formed so as to surround in a press-fit state.