JP2001157434A - Rotor for stepping motor and stepping motor incorporating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bond a bush at a rotor for a stepping motor to a magnet in a simple working process and strongly. SOLUTION: The rotor 22 is composed of a rotor shaft 26. The rotor is composed of the bush 27 which is shaft-mounted on the rotor shaft 26. The rotor is composed of the magnet 28 which is bonded integrally to the bush 27 on the outer circumferential face of the bush 27. In the rotor 22 for the stepping motor, the outer circumferential face in the tip of the bush at the rotor 22 is cut off obliquely, a recessed part 33 is formed between the outer circumferential face and the magnet 28, an adhesive 37 is filled into the recessed part 33, and the bush 27 and the magnet 28 are bonded. In the rotor for the stepping motor, a step 35 is formed in the circumference of the obliquely cut-off face 34, grooves 36, 36,... are formed in a plurality of places in the step 35, the adhesive 37 is filled into the step 35, the grooves 36, 36,... and the recessed part 33, and the bush 27 and the magnet 28 are bonded after the adhesive 37 is hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a stepping motor and a stepping motor including the rotor therein, and more particularly to a rotor for a stepping motor having a rotor bush and a magnet which are firmly joined to each other. The present invention relates to an installed stepping motor.

[0002]

2. Description of the Related Art A conventional stepping motor of this type will be described with reference to FIGS. First, the rotor 1 of the stepping motor shown in FIGS. 5 and 6 will be described. The rotor 1 includes a rotor shaft 2 provided in a longitudinal direction of a center portion of the rotor 1, a bush 3 rotatably mounted on an outer peripheral surface of the rotor shaft 2, and a bush 3 on an outer peripheral surface of the bush 3. Bush 3
And a magnet 4 joined thereto.

The magnet 4 is formed of a hollow cylindrical magnetic material, and a plurality of protruding portions 5 are provided on the inner peripheral surface of the left end of the magnet 4 so as to project in the axial direction.

On the other hand, the bush 3 is made of a non-magnetic synthetic resin, and comprises a cylindrical small diameter portion 6 in the left half and a cylindrical large diameter portion 7 in the right half. . A gear 8 is engraved on the outer peripheral portion of the small diameter portion 6 on the left side, so that the magnet 4 is joined to the outer peripheral surface of the large diameter portion 7.

Further, the outer peripheral surface at the right end of the large diameter portion 7 is beveled, and a concave portion 9 is formed between the magnet 4 and the bush 3. In the drawing, reference numeral 10 denotes a hollow portion.

In order to join the bush 3 and the magnet 4, first, the small diameter portion 6 of the bush 3 is inserted into the magnet 4 from the right side opening portion of the magnet 4 with the small diameter portion 6 facing forward. The left end of the large-diameter portion 7 of the bush 3 is positioned by contacting the projecting portion 5 of the magnet 4, and then the adhesive 9 is filled in the recess 9 of the bush 3,
After the adhesive 11 is cured, the bush 3 and the magnet 4 are joined.

Next, the stepping motor rotor 12 shown in FIG. 7 will be described. The rotor 12 has a rotor shaft 13, a bush 14 rotatably mounted on the outer peripheral surface of the rotor shaft 13, and a bush 14 joined to the outer peripheral surface of the bush 14, similarly to the aforementioned rotor 1. The outer peripheral surface of the end of the bush 14 is shown in FIG.
The magnet 1 is obliquely cut off similarly to the bush 3 shown in FIG.
A recess 16 is formed between the recess 5 and the recess 5.

Further, the rotor 12 has a plurality of projections 17, 17...
Also, a fitting recess 1 for fitting the projections 17, 17,...
Are provided on the outer peripheral surface of the bush 14, and the projections 17, 17 and the fitting recesses 18, 18,. Are configured to perform a mutual rotation stop function.

The rotor 12 is provided with the fitting recess 1.
The outer peripheral surface of the bush 14 including 8, 18,.
An adhesive 19 is filled between the inner peripheral surface of the magnet 15 including 7, 7,... And between the concave portions 16, and the bush 14 and the magnet 15 are joined after the adhesive is cured.

[0010]

In the rotor of the stepping motor shown in FIGS. 5 and 6, a predetermined concave portion is formed between the inclined surface and the magnet by beveling the outer peripheral surface of the tip of the bush. Since the recess is filled with an adhesive and the bush and the magnet are joined after the adhesive is cured, the bonding surface of the bush and the magnet is a flat surface composed of a circle and a circle. In addition, there has been a defect that the joint strength between the bush and the magnet is not sufficiently ensured, and rotation stop between the bush and the magnet is not guaranteed.

The rotor of the stepping motor shown in FIG. 7 has, in addition to the structure of the rotor described above, a plurality of protrusions projecting from the inner peripheral surface of the magnet, and a plurality of protrusions are provided on the outer peripheral surface of the bush corresponding to the protrusions. Since the fitting recesses are provided, the projections and the fitting recesses are matched with each other to fit each other, and the magnet and the bush are configured so as to prevent mutual rotation.
At the time of assembly, the bush and the magnet need to be aligned with each other, so that the workability in assembling is poor and the cost is increased.

Accordingly, in a rotor for a stepping motor and a stepping motor having the rotor therein, there is a technical problem to be solved so that the bush and the magnet can be firmly joined to each other in a simple operation process. A problem arises, and the present invention aims to solve this problem.

[0013]

DISCLOSURE OF THE INVENTION The present invention has been proposed to achieve the above object, and has a rotor shaft, a bush mounted on the rotor shaft, and a bush on an outer peripheral surface of the bush. And a magnet integrally joined to the rotor, wherein the outer peripheral surface of the bush tip end portion is beveled to form a recess between the rotor and the magnet, and the recess is filled with an adhesive. In the stepping motor rotor formed by joining the bush and the magnet, a step is formed around the beveled surface and grooves are formed at a plurality of positions of the step, and the step, the groove, and A stepping motor rotor in which the recess is filled with an adhesive, and the bush and the magnet are joined after the adhesive is hardened, and the groove has an opening width at an inlet of the groove, the maximum width of which is inside the groove. Smaller size And a rotor comprising a rotor shaft, a bush fixed to the rotor shaft, and a magnet integrally joined to the bush on the outer peripheral surface of the bush. The rotor has a rotor in which the outer peripheral surface of the bush tip of the rotor is beveled and a recess is formed between the rotor and the magnet, the recess is filled with an adhesive, and the bush and the magnet are joined. In the stepping motor, a step is formed around the inclined surface, grooves are formed at a plurality of positions of the step, and the step, the groove and the recess are filled with an adhesive, and the adhesive is formed. An object of the present invention is to provide a stepping motor in which a rotor formed by joining the bush and the magnet after being cured is housed in a casing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. In FIG. 1, reference numeral 20 denotes a stepping motor. The stepping motor 20 includes a rotor 22 rotatably supported in a casing 21, a stator 23 disposed on the outer periphery of the rotor 22, and a stepper motor 20 mounted on an outer peripheral surface of the stator 23 and winding a coil 24. And a bobbin 25 mounted thereon.

Further, as shown in FIG. 2, the rotor 22 has a rotor shaft 26 provided in the longitudinal direction of the center of the rotor 22.
A bush 27 rotatably mounted on the outer periphery of the rotor shaft 26; and a magnet 28 disposed on the outer periphery of the bush 27. The magnet 28 is formed of a hollow cylindrical magnetic material, and a plurality of projecting portions 29 project from the inner peripheral surface of the left end of the magnet 28 in the axial direction.

On the other hand, the bush 27 is made of a non-magnetic synthetic resin, and has a cylindrical small diameter portion 30 in the left half.
A right-half cylindrical large-diameter portion 31 is provided. A gear 32 is engraved on the outer peripheral portion of the small diameter portion 30 on the left side, and the magnet 28 is joined to the outer peripheral surface of the large diameter portion 31.

Thus, as in the conventional example, the large diameter portion 31
The outer peripheral surface of the right end portion is obliquely notched, and a concave portion 33 is formed between the magnet 28 and the bush 27. Further, as shown in FIGS.
5 are provided around the groove portion 36,
Are provided in the axial direction and over a predetermined depth.

Therefore, the bush 27 is connected to the magnet 2
In order to assemble the bush 27 and join the two, first, the bush 27 is inserted into the magnet 28 from the right opening of the magnet 28 with the small-diameter portion 30 of the bush 27 forward, and the bush 27 is The left end surface of the large diameter portion 31 is brought into contact with the inner surface of the projecting portion 29 of the magnet 28, and then the step portion 35 and the groove portions 36, 36,.
The recess 37 is filled with an adhesive 37, and after the adhesive 37 is cured, the bush 27 and the magnet 28 are filled.
Is firmly joined. At this time, the groove 3
The adhesive 37 filled in 6, 36... Integrally joins the magnet 28 and the bush 27, and in particular, is configured to sufficiently exhibit the function of stopping rotation of both.

Further, the bush 27 inserted in the magnet 28 is restricted from moving leftward in the axial direction by the protrusion 29 provided at the left end of the magnet 28, and is moved rightward. In this case, the rightward movement in the axial direction is restricted by the adhesive 37 filled in the grooves 36.

Further, the groove 36 is formed such that the opening width B of the entrance 38 of the groove 36 is smaller than the maximum width C inside the groove 36, whereby the adhesive filled in the groove 36 is formed. 37 also regulates the movement of the magnet 28 and the bush 27 in the direction away from each other by the small-sized entrance portion 38 of the groove portion 36.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0022]

According to the present invention, as described in detail in the above embodiment, the invention according to claim 1 is a rotor for a stepping motor, wherein the outer peripheral surface of the tip of the bush of the rotor is beveled. In a rotor having a recess formed between the bush and the magnet, a step is provided around the beveled surface, and grooves are formed at a plurality of positions of the step, and the step, the groove, and the Since the recess is filled with an adhesive and the bush and the magnet are joined after the adhesive is hardened, the operation of centering the bush and the magnet as in the conventional example is not required, and the recess is simply provided. When the adhesive is filled, the adhesive naturally flows into the step portion and the groove portion, and the magnet and the bush mutually move in the rotational direction and the axial direction after the adhesive is hardened. Are regulated, and both sides are extremely strong and integrated Than it is engaged.

Further, according to the present invention, the opening width of the entrance of the groove is formed to be smaller than the maximum width inside the groove, and the adhesive flows into the groove and is hardened. Thus, the movement of the bush and the magnet in the direction away from each other is also restricted by the small-sized entrance portion of the groove.

The third aspect of the present invention is directed to the first aspect.
Alternatively, since the stepping motor has the rotor according to the second aspect incorporated therein, a stepping motor having the above-described operational effects can be obtained.

As described above, the present invention has a remarkable effect that the bush and the magnet of the rotor for the stepping motor can be joined firmly to each other in a simple working process and can contribute to cost reduction. It is the invention which plays.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention, and is a partially cut-away longitudinal sectional view of a stepping motor.

FIG. 2 is a longitudinal sectional view showing the stepping motor rotor of FIG. 1;

FIG. 3 is a right side view of FIG. 2;

FIG. 4 is a sectional view taken along line AA of FIG. 2;

FIG. 5 is a longitudinal sectional view showing a conventional example and showing a rotor for a stepping motor.

FIG. 6 is a right side view of FIG. 5;

FIG. 7 is a right side view showing another conventional example and showing a rotor for a stepping motor.

[Explanation of symbols]

 Reference Signs List 22 rotor 26 rotor shaft 27 bush 28 magnet 33 concave portion 34 inclined surface 35 stepped portion 36 groove portion 37 adhesive

Claims (3)

[Claims] 1. A rotor comprising a rotor shaft, a bush fixed to the rotor shaft, and a magnet integrally joined to the bush on an outer peripheral surface of the bush, wherein a tip end of the bush of the rotor is provided. In the stepping motor rotor, the outer peripheral surface is obliquely cut to form a recess between the magnet and the recess, and the recess is filled with an adhesive and the bush and the magnet are joined. A step is formed around the notched surface, grooves are formed at a plurality of positions of the step, an adhesive is filled in the step, the groove, and the recess, and after the adhesive is hardened, the bush, the magnet and A rotor for a stepping motor, wherein the rotor is joined. 2. The stepping motor rotor according to claim 1, wherein the groove is formed such that an opening width at an entrance of the groove is smaller than a maximum width inside the groove. 3. A rotor comprising: a rotor shaft; a bush fixed to the rotor shaft; and a magnet integrally joined to the bush on an outer peripheral surface of the bush. In the stepping motor having a rotor in which a concave portion is formed between the magnet and the outer peripheral surface, the concave portion is formed between the magnet and the bush, and the bush and the magnet are joined together. A step is formed around the beveled surface, grooves are formed at a plurality of positions of the step, an adhesive is filled into the step, the groove, and the recess, and the bush is formed after the adhesive is cured. A stepping motor, wherein a rotor formed by joining a magnet is housed in a casing.