JPS63283446A - Dc motor - Google Patents

Abstract

PURPOSE:To prevent the malfunction of a speed detecting element by fitting and fixing a cylindrical magnetic shielding plate in the circumferential groove of a ring insulating plate provided on the end faces of a stator core. CONSTITUTION:Insulating plates 3 and 8 are provided on both end faces of a cylindrical stator core 1 surrounding a rotor 5, and a printed plate 7 is immovably installed on the inside face of a motor axially opposed to one insulating plate 3. Also, a cylindrical magnetic shielding plate 4 is fitted and fixed in said insulating plate 3. On the inside of said magnetic shielding plate 4, a rotational speed detecting element 6 connected with the said printed plate 7 and immovably supported by said shielding plate 4 is arranged radially in opposition to the end outer periphery of said rotor 5. In this manner, said rotational speed detecting element 6 for the rotor 5 is arranged on the inside of a coil end 2a protruding from the end face of said iron core 1, via the cylindrical magnetic shielding plate 4 fitted and fixed in the insulating plate 3, to enable prevention of the malfunction of said rotational speed detecting element 6 and improvement in assembling properties of an apparatus.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a DC motor in which a rotor rotational speed detection element is disposed inside the coil end, in which magnetism generated from the coil is shielded with a structure that is easy to assemble. The present invention relates to a sensor capable of preventing malfunction of a detection element.

[Conventional technology]

When installing a rotor rotation speed detection element inside the coil end of a DC motor, a cylindrical shielding plate is generally installed on a printed board to shield the magnetism generated from the coil and prevent the detection element from malfunctioning. When installing, this printed board was fixed to the inside surface of the motor.

[Problem that the invention seeks to solve]

This structure not only complicates the structure of the printed circuit board, but also has the disadvantage that the coil may be damaged at the tip of the shield plate during motor assembly.

In order to eliminate the above-mentioned drawbacks, this invention shields the magnetism generated from the coil with a structure that is easy to assemble to prevent malfunction of the rotor rotational speed detection element disposed inside the coil end. The purpose of this invention is to provide a DC motor with

[Means for solving problems]

In order to achieve the above object, the present invention provides an annular insulating plate having an insertion groove 8a for the coil 2 on the end face of the cylindrical stator core 1 and a circumferential groove 3b on the outer surface of the inner circumference. 3, and a cylindrical magnetic shielding plate 4 is fitted and fixed in the circumferential groove 3b, and the rotor 5 is inserted into the inside of the coil end 2a protruding from the end face of the iron core 1 via the magnetic shielding plate 4. A rotational speed detection element 6 is provided.

[Effect]

Since the cylindrical magnetic shielding plate 4 is fitted and fixed in the circumferential groove 3b of the annular insulating plate 8 provided on the end face of the stator core 1, damage to the coil 2 can be prevented during motor assembly. Not only is this possible, but the structure of the printed board 7 is also simplified.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which both end surfaces of a cylindrical stator core 1 surrounding a rotor 5 are made of nylon 66, for example.
Annular insulating plates 3 and 8 made of resin such as the like are provided, and a printed board 7 is fixedly attached to the inner surface of the motor that faces one of the insulating plates 3 in the axial direction. The rotor 5 is made of a permanent magnet, and has both ends extending outward from the end face of the iron core 1 so as to be longer than the iron core 1 in the axial direction. - As shown in FIGS. 2 to 4, the insulating plate 8 has a large number of insertion grooves 3a for the coil 2 on the inner periphery, and has grooves 3a disposed intermittently in the circumferential direction on the outer surface of the inner periphery. A circumferential groove 8b is formed in the distal end surface of the protrusion 8C. Inside the coil insertion groove 8a, a substantially cylindrical insulator 8d is integrally formed on the peripheral edge of the groove 3a, and is fitted into the coil insertion groove of the iron core 1 (not shown) to electrically insulate the iron core 1 and the coil 2. A cylindrical magnetic shielding plate 4 is fitted into the circumferential groove 3b and, if necessary, is fixed and attached with an adhesive or the like. Although the other insulating plate 8 is illustrated as a simple annular plate, the present invention is not limited to this, and it may be made to have the same shape as the one insulating plate 3, or may be omitted. Inside the magnetic shielding plate 4, a rotational speed detection element 6 for the rotor 5, which is made of a Hall element or the like connected to and fixedly supported by the printed board 7, is arranged radially opposite to the outer periphery of the end of the rotor 5. has been done.

According to the embodiment, the rotational speed detection element of the rotor 5 is connected to the inner side of the coil end 2a protruding from the end face of the iron core 1 through the cylindrical magnetic shielding plate 4 fitted and fixed in the circumferential groove 3b of the insulating plate 8. 6, it is possible not only to prevent damage to the coil 2 when assembling the motor, but also to facilitate the insertion of the coil 2 by using the insulating plate 3. Furthermore, the structure of the printed board 7 is also explained in the conventional example. It becomes easier than anything else.

In the embodiment described above, a case has been described in which a permanent magnet is used in the rotor 5 and a cylindrical insulator 3d is provided on the inner surface of the insulating plate 3, but the present invention is not limited thereto.

〔Effect of the invention〕

According to this invention, in a DC motor in which a rotor rotational speed detecting element is arranged inside the coil end, the stator core has a coil insertion groove on the end face and a circumferential groove on the outer surface of the inner circumference. A ring-shaped insulating plate is provided, and a cylindrical shielding plate that shields the magnetism generated from the coil is fitted into the circumferential groove to prevent malfunction of the detection element. The effects of preventing damage to the coil and making it easier to insert the coil can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is an enlarged longitudinal sectional view of the insulating plate of Fig. 1, Fig. 3 is a side view of Fig. 2 as seen from the top direction, and Fig. 4. is a side view seen from the Q sky direction in FIG. 2. DESCRIPTION OF SYMBOLS 1... Iron core, 2... Coil, 2a... Coil end, 8... Insulating plate, 3a, 3b... Groove, 4... Shielding plate, 5... Rotor, 6... ...Detection element.

Claims (1)

[Claims] 1) An annular insulating plate having a coil insertion groove on the end face of the cylindrical stator core and a circumferential groove formed on the outer surface of the inner circumferential part is provided, and a cylindrical magnetic insulating plate is provided in the circumferential groove. A direct current motor characterized in that a shielding plate is fitted and fixed, and a rotor rotational speed detecting element is disposed inside a coil end protruding from the end face of the iron core via a magnetic shielding plate.