JPH0559237U - Magnet plate for rotation detection and its mounting structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a magnet plate having a structure in which there is little variation in the fixing strength when fixing it on a rotor shaft and which does not take much time for attachment, and an attachment structure thereof. [Structure] A disc-shaped main body 12 made of a magnetic material, and a synthetic resin cylindrical boss provided in the central portion of the main body 12 for mounting the main body 12 on a rotor shaft 18. In the rotation detecting magnet plate having the portion 14, the boss portion 14 is provided with a single or a plurality of slits 16 that open in the front end direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotation detecting magnet plate (hereinafter, simply referred to as a magnet plate) which is mounted on a rotor shaft of a motor or the like and generates a signal having a frequency corresponding to the rotation speed of the rotor.

[0002]

[Prior Art]

 FIG. 2 is a perspective view showing the structure of a conventional magnet plate. As shown in FIG. 2, a magnet plate 50 is conventionally formed of a disk-shaped main body 52 using a resin magnet as a magnetic material, and a cylindrical shape using a synthetic resin material. A boss portion 54 for fixing the main body portion 52 thereon. Through holes 55 are formed in the body portion 52 and the boss portion 54 along the axis. The inner diameter of the through hole 55 is formed to be slightly larger than the outer diameter of the rotor shaft 18 of the motor or the like. When fixing the magnet plate 50 on the rotor shaft 18, the rotor shaft 18 is inserted into the through hole 55 of the magnet plate 50, and after moving to a predetermined position, the adhesive 56 is applied to the through hole 55 and the rotor. It is injected and fixed between the shafts 18.

[0003]

[Problems to be solved by the device]

 However, the structure of the conventional magnet plate described above has the following problems. When the magnet plate 50 is fixed onto the rotor shaft 18, since it is fixed with the adhesive 56 as described above, the adhesive strength will fluctuate unless the amount of the adhesive 56 used is properly controlled. .. In addition, since work steps for bonding and drying are required, there is a problem that the number of work steps increases and the production cost rises. Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a magnet plate and a structure having a structure in which there is little variation in the fixing strength when fixed on a rotor shaft and which does not take a long time to install. It is to provide the mounting structure.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the rotation detecting magnet plate of the present invention has the following configuration. That is, a disc-shaped main body made of a magnetic material and a synthetic resin cylindrical body provided at the center of the main body for mounting the main body on the rotor shaft. In the rotation detecting magnet plate having the above, the boss portion is provided with a single slit or a plurality of slits that are open in the front end direction. In addition, the rotor shaft is inserted through the boss portion of the rotation detecting magnet plate having the above-mentioned structure, and at the same time, a fastening member is attached to the boss portion to reduce the diameter of the boss portion and fixed on the rotor shaft. It is good to

[0005]

[Action]

 The operation will be described. According to the present invention, since the slit is formed in the boss portion of the magnet plate, the tip of the boss portion can be expanded or reduced in diameter, and after the rotor shaft is inserted through the boss portion of the magnet plate. If a tightening member such as a spring band is attached to the boss, the tip of the boss is pressed against the rotor shaft due to the diameter reduction action of the spring band, and the magnet plate is fixed on the rotor shaft due to frictional force. ..

[0006]

【Example】

 Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an external view showing the structure of the magnet plate of this embodiment. First, the configuration will be described. The magnet plate 10 is composed of a disk-shaped main body 12 made of a resin magnet as a magnetic material, and a boss 14 made of a synthetic resin material and formed into a cylindrical body having a flange portion at one end. The flange side of the boss portion 14 is fixed to the central portion of the main body portion 12 with an adhesive or the like so as to vertically project. Further, a through hole 15 is formed in the central portion of the main body portion 12 and the boss portion 14 along the axis, and the inner diameter of the through hole 15 is formed slightly larger than the outer diameter of the rotor shaft 18. Further, the outer wall of the boss portion 14 is provided with two slits 16 that are open toward the tip and are substantially parallel to the axial direction. Since the boss portion 14 is made of a resin material, the tip end portion of the boss portion 14 can be reduced in diameter or expanded in diameter with the other end portion on the main body portion 12 side as a fulcrum.

Next, when fixing the magnet plate 10 onto the rotor shaft 18 such as a motor, the rotor shaft 18 is inserted into the through hole 15 of the magnet plate 10. After sliding the rotor shaft 18 over and moving the magnet plate 10 to a predetermined position, a spring band 20 as a fastening member is attached to the boss portion 14. The boss portion 14 is pressed against the rotor shaft 18 due to the diameter reduction action of the spring band 20, and therefore the magnet plate 10 is rotated by the frictional force between the inner peripheral surface of the boss portion 14 and the outer peripheral surface of the rotor shaft. It is fixed on the child shaft 18.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the number of slits may be one or three or more instead of two. Also good. Instead of providing the flange on the boss portion, a hole may be formed in the central portion of the main body portion and the boss portion may be fitted and fixed in the hole. The inner diameter of the boss portion may be gradually reduced from the main body portion side to the front end portion so that the boss portion may have a spring effect when the slit is provided. Instead of manufacturing the main body and the boss separately and fixing them with an adhesive, the main body and the boss may be integrally formed using a resin magnet. Of course, it is possible to modify.

[0009]

[Effect of the device]

 Since the rotation detecting magnet plate according to the present invention has the slit formed in the boss portion of the cylindrical body, the rotor shaft is inserted through the boss portion of the magnet plate, and then the fastening member is attached to the boss portion to reduce the contraction. By making the diameter, it can be easily fixed on the rotor shaft without using an adhesive, the working time can be shortened and the man-hours can be reduced, and the fixing with uniform strength can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outer shape of a rotation detecting magnet plate according to the present invention and a structure for mounting it on a rotor shaft.

FIG. 2 is a perspective view showing an outer shape of a conventional rotation detecting magnet plate and a structure for mounting it on a rotor shaft.

[Explanation of symbols]

 10 Rotation Detecting Magnet Plate 12 Main Body 14 Boss 16 Slit 18 Rotor Shaft

Claims (2)

[Scope of utility model registration request] 1. A disk-shaped main body made of a magnetic material, and a synthetic resin cylindrical boss provided in the central portion of the main body for mounting the main body on the rotor shaft. A magnet plate for rotation detection having a portion, wherein the boss portion is provided with a single or a plurality of slits opening in the front end direction. 2. The rotor shaft is inserted through the boss portion of the magnet plate for rotation detection according to claim 1, and a fastening member is attached to the boss portion to reduce the diameter of the boss portion so that the rotor shaft is mounted on the rotor shaft. Attachment structure of magnet plate for rotation detection, which is fixed.