JPH01229088A - Bonding between shaft and bore consisting of porous form - Google Patents

Abstract

PURPOSE:To provide the title bonding process so designed that a shaft and the bore of a porous form impregnated with a curable synthetic resin are mutually inserted and a liquid adhesive is injected into the gap between them, thereby securing high bond strength between then and ensuring automatic bonding in mass-productive fashion with quick drying and good workability. CONSTITUTION:A rotor R produced by compression molding of a neodymium iron boron-based magnet as a porous form is impregnated with e.g., a liquid epoxy resin to fill the fin pores to form the first film f1. Thence, the resultant rotor R is coated with e.g., a fluororesin to form a rest-resisting film f2. A shaft 1 is then inserted into the bore of the above rotor R followed by injection of a liquid adhesive into the mating gap, resulting in drying of said adhesive which is left on the contact surface. The resin to be used for forming the first film f1 may be, other than an epoxy resin, a curable liquid acrylic resin or a lac varnish or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Separation) The present invention relates to an adhesion method in which one of the holes or shafts of a porous body is inserted into the other, and an adhesive liquid is injected to bond the two.

(Prior Art) Generally, when bonding porous bodies with an adhesive, an adhesive with relatively high viscosity is used. In other words, if an adhesive with low viscosity is used, it will be absorbed into the pores of the porous material before it hardens, and no adhesive will remain on the contact surface with the adhered object, making it impossible to obtain strong bonding strength. .

On the other hand, adhesives with high viscosity have difficulty entering areas with small gaps between bonding surfaces, and are not suitable for bonding a shaft and a hole with a small fit-in gap, where dimensional accuracy is important.

(Object of the Invention) In view of the above-mentioned problems, an object of the present invention is to provide a method of adhering a hole containing a porous body and a shaft to obtain strong bonding force even in a state where there is a small gap between the holes.

(Specific Means for Achieving the Object) In order to achieve the above object, according to the present invention, the hole including the porous body and the porous body of the shaft are impregnated with a curable synthetic resin liquid, Alternatively, the present invention proposes a method of bonding a shaft and a hole made of a porous material by inserting one of the shafts into the other and injecting an adhesive into the fitting portion to bond both shafts.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view showing the entire stepper motor used in a camera, and shows a motor block M that is arranged in a circular hole shape around a lens optical axis P and drives a shutter and an automatic focusing lens.

The rotor R is a permanent magnet magnetized with four poles, and is bonded to the shaft 1 with adhesive.
are press-fitted together.

The two stators SA, SB are fixed to the motor block M at symmetrical positions with respect to the rotor R by shafts S1, S2. Further, the coils LA and LB are inserted into the stators SA and SB, respectively, and are controlled to be energized by a known motor drive circuit Q.

In such a configuration, the drive circuit Q drives the coils LA and LB.
When the drive pulses are sequentially applied to the stators SA, SB
are sequentially excited, and each magnetic pole of rotor R is connected to stator SA, S
Attractive or repulsive action occurs in response to the pole B, and the rotor R
rotates forward or backward around the shaft 1, and a pinion connected to the tip of the shaft 1 operates a shutter or an automatic focusing lens.

By the way, since a shutter or an automatic focusing lens requires a highly responsive and powerful motor, it is important to carefully select the magnetic material and dimensional accuracy of the stators SA, SB and rotor R.

The rotor R uses a samarium cobalt magnet, but if a compression molded neodymium iron boron magnet, which has even better characteristics, is used, the maximum energy product is large, so a powerful motor with good response can be constructed.

However, since neodymium iron boron magnets are porous, when bonding them to the shaft 1, a sufficient gap is provided so that the high viscosity adhesive can fully enter the adhesive surface, and a long time is allowed for the adhesive to harden. There must be.

On the other hand, in order to construct a powerful motor with uniform response, it is important that the gaps between the magnetic poles of stators SA and SB and the outer periphery of rotor R be small and uniform. The fit gap between the rotor R and the shaft 1 needs to be kept at about 10-odd microns in order to reduce the eccentricity of the rotor R with respect to the shaft 1.

When joining the rotor R and the shaft 1 in such a situation, the high viscosity adhesive no longer sufficiently enters the small gap, and
The amount of adhesive that can enter is absorbed into the inner surface of the hole in the rotor R, and a sufficient bonding force cannot be obtained.

Furthermore, high viscosity adhesives generally take a long drying time and must be left for a long time in order to obtain strong overall strength, making them difficult to mass-produce.

Furthermore, low viscosity adhesives are more likely to be absorbed by the inner surface of the hole and will not remain on the bonding contact surface, resulting in no bonding strength.

Fig. 2 shows a cross section of the joint between the rotor R and the shaft 1, which shows the main part of the present invention. is impregnated to fill minute pores to form a first film fl, and then a fluorocarbon resin is applied to form a rust preventive film f2.

These coatings are processed and dried on the rotor R as a single unit, and the thickness of the coating is approximately several microns.

Next, the shaft 1 is inserted into the hole in the rotor R, and liquid adhesive is injected into the gap between the holes. When the inner surface of the hole in the rotor R is coated with
Since the adhesive is covered by l and f2, it dries while remaining on the contact surface.

Liquid adhesive dries quickly and is suitable for mass production, and is convenient for automation.Also, even when there is a small gap between the hole and shaft 1 as in the example, it can sufficiently penetrate into the bonding surface and provide strong bonding force. .

In addition to the above, the resin forming the first film f1 may be any liquid curable material such as acrylic resin or lacquer varnish.

Further, the resin forming the rust-preventing film f2 is not limited to those mentioned above, and any paint having a rust-preventing effect may be used.

Furthermore, the present invention is not limited to the above-mentioned embodiments, but can be similarly implemented even when the shaft is a porous body depending on the application, and can be applied to other joints of porous bodies that require dimensional accuracy.

(Effects) As is clear from the above explanation, since the surface of the porous body is sealed by the first film, a liquid adhesive can be used when bonding the shaft 1, and a strong bonding force is achieved. This bonding method is fast, easy to work with, and suitable for mass production and automation.

Furthermore, a film that provides a rust-preventing effect is easily formed.

Therefore, the present invention is an effective method suitable for bonding porous materials to achieve extremely high precision bonding conditions.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall plan view of a step motor, and FIG. 2 is a sectional view of a main part. １・・・・・・・・・・・・Rotor axis R・・・・・・
・・・・・・Rotor (porous body) 2・・・・・・・・・
・・・・・・Binion bi・・・・・・・・・・・・
・Motor block SA, SB・・Stator LA, LB・・Coil Q・・・・・Drive circuit f1・・・・First film f2・・・・・・・・・・・μ】Silver film or more

Claims (1)

[Claims] The hole containing the porous body and the porous body of the shaft are impregnated with a curable synthetic resin liquid, and the other is inserted into one of the holes or the shaft, and an adhesive liquid is injected into the fitting part to bond them together. A method of bonding a shaft and a hole made of a porous material to be bonded.