JPH0382360A - Stepping motor provided with rotational vibration preventive device - Google Patents

Abstract

PURPOSE: To realize a stepping motor provided with a small rotational vibration preventer having high manufacturability by arranging a resilient body and a weight while stacking in the thrust direction of a rotor thereby decreasing the maximum diameter of the rotational vibration preventer. CONSTITUTION: A disc-like resilient body 7 causes no unbalance in the rotational system and has a specified thickness. Since adhesive layers 9, 10 are applied previously to the opposite side faces of the resilient body 7, the resilient body 7 and the adhesive layers 9, 10 provide a three layer structure. The resilient body 7 is disposed concentrically to a rotor 2 while being bonded, on one side face thereof, to the end face 6a of an output gear 6 through any one adhesive layer. A weight 8 has a larger diameter than the resilient body 7 and bonded to the other side face thereof through the adhesive layer 10 while being arranged coaxially with the rotor 2. A motor 1 provided with the rotational vibration preventer 5 is built in a business machine.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention can be used, for example, as a drive source for a paper feed mechanism of a printer, a drive source for a mechanism that moves a head carrier on which a print head is mounted, or other office equipment. The present invention relates to a stepping motor used as a drive source for various applications, and particularly relates to a stepping motor in which a device for preventing rotational vibration is attached to the rotor.

[Conventional technology]

A stepping motor is rotated by one step angle by switching the excitation phase of the stator according to an input pulse, and the input coil is applied in a stepwise manner. Therefore, each time an input pulse is applied, the angular displacement (step angle) of the rotor shaft responds as shown in Figure 9, and a large peak portion as shown by A in Figure 9 is formed for each step. be done. Therefore, the occurrence of these peak portions A causes vibrations and noise based thereon.

In order to avoid such problems, a rotational vibration prevention device C is attached to the rotor shaft of the conventional stepping motor a, as shown in FIGS. 7 and 8.

This device C consists of a boss e fixed to one end of the rotor shaft by a screw d, a ring-shaped weight f surrounding the boss e and arranged concentrically on the outside thereof, and the boss e and the weight f. and a ring-shaped elastic body g made of rubber. The weight f provides an inertial mass to the rotor h of the stepping motor a. The parts other than the screw d of this rotational vibration prevention device C are formed by setting the boss e and the weight f in a mold for the elastic body g in advance, and then injecting and filling the mold with a rubber material. This is obtained by connecting the boss e and the weight f using the elastic body g at the same time as the molding. Note that i in FIG. 7 is an output gear attached to the other end of the rotor shaft.

In such a rotational vibration prevention device C, resistance based on the elastic deformation of the elastic body g acts against mutual movement between the rotor shaft and the weight f arranged in the radial direction of the rotor shaft. This resistance provides a damping force against fluctuations in the rotational speed of the rotor h, making it possible to reduce vibration and noise.

[Problems to be Solved by the Invention] However, in the conventional rotational vibration prevention device C, the boss e2, the elastic body g, and the weight f that constitute the device are continuous so that they overlap in the radial direction of the rotor shaft. The outer diameter of the device C is large because the two are connected to each other. Therefore, in motors that are becoming smaller, such as stepping motors used in office equipment, for example, the rotational vibration prevention device C is smaller than the outer diameter of the frame of motor a, as shown in Figure 7. There is a problem in that the diameter becomes large, leading to a substantial increase in the size of the motor.

In addition, since the rotational vibration prevention device C is manufactured as described above, it is troublesome to set the boss e and the weight f in the mold, resulting in poor productivity.

An object of the present invention is to provide a stepping motor with a rotational vibration prevention device that is not only capable of reducing vibration and noise of the motor but also is compact and easy to manufacture.

[Means for Solving the Problem] In order to achieve the above object, in the stepping motor with a rotational vibration prevention device of the present invention, the rotational vibration prevention device is attached to the end of the rotor shaft of the rotor, and the rotational vibration prevention device is attached to the end of the rotor shaft of the rotor. The fixing device is also formed of a large-diameter fixing device and a rubber-like substance with a predetermined thickness, and one side is attached to the end surface of the fixing device along the direction orthogonal to the axial direction of the rotor shaft via an adhesive layer. an elastic body that is bonded and arranged concentrically with the rotor axis; and an elastic body having a predetermined thickness;
and a weight that is adhered to the other side of the elastic body via an adhesive layer and is arranged concentrically with the rotor axis to provide an inertial mass to the rotor.

Furthermore, in order to prevent the weight from causing a short circuit in the event that the weight comes off, it is preferable to form the weight with a non-conductive material.

In order to prevent the rotational vibration prevention device from being subjected to external force that would cause it to peel off, and to reduce the axial length of the motor, the rotational vibration prevention device is made of rubber-like material with a predetermined thickness and a center portion. is formed with a rotor shaft through hole, one side is bonded via an adhesive layer to an end surface of the rotor main part of the rotor located within the motor frame, and the rotor is concentric with the rotor shaft of the rotor. The elastic body is formed to have a predetermined thickness and has a rotor shaft through hole in the center, and is bonded to the other side of the elastic body via an adhesive layer to form the rotor shaft. and a weight arranged concentrically with the rotor to provide an inertial mass to the rotor.

Furthermore, in order to more easily attach the rotational vibration prevention device to the rotor, adhesive layers on both sides of the elastic body are attached to the elastic body in advance, and these adhesive layers and the elastic body form a three-layer structure. It is better to configure it.

Further, in order to further reduce rotational vibration, the adhesive layer may be formed of an adhesive material.

[Operation] Since the weight provides inertial mass to the rotor, each time the rotor rotates by one step angle, the elastic body between the weight and the fixture attached to the rotor shaft is elastically deformed. That is, since a resistance based on the elastic deformation of the elastic body acts against the mutual movement of the rotor and the weight, this resistance can provide a damping force against fluctuations in the rotational speed of the rotor. Since the elastic body and the weight are arranged in a stacked manner in the thrust direction of the rotor, the maximum diameter of the rotational vibration prevention device, that is, the diameter of the weight can be reduced.

Moreover, since the elastic body and the weight are each attached via an adhesive layer, there is no need to use a mold to connect them together, and this rotational vibration prevention device can be easily attached to the rotor. .

Furthermore, there is a possibility that the weight may peel off due to deterioration of the adhesive layer of the rotational vibration prevention device. However, if the weight is made of a non-conductive material, even if the weight falls onto a circuit section of a device equipped with a motor, the weight will not cause a short circuit in the circuit.

If the rotational vibration prevention device is provided within the motor frame by adhering to the end face of the rotor main portion, the prevention device can be covered by the motor frame. And the inner rotor type stepping motor is
Generally, a dead space is formed between the end face of the rotor main portion and the motor frame. Therefore, since this space can be effectively utilized to provide the above-mentioned prevention device, the axial dimension of the entire motor can be shortened.

Furthermore, if the elastic body and the adhesive layers on both sides have a three-layer structure in advance, when adhering the elastic body to the end face of the fixture or the end face of the rotor main part, and adhering the weight to this elastic body, There is no need to apply adhesive or adhere adhesive material each time, and the elastic body can be easily bonded via adhesive layers on both sides.

Further, when the adhesive layer is an adhesive material, the viscosity of the adhesive layer functions similarly to an elastic body, so that rotational vibration can be further suppressed.

[Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

Reference numeral 1 in FIG. 1 is a permanent magnet type stepping motor, and the end of a rotor shaft 3 of the rotor 2 projects outside of a motor frame 4 in which the main portion of the rotor 2 is housed. A rotational vibration prevention device 5 is attached to one end of the rotor shaft 3 to provide a damping force against fluctuations in the rotational speed of the rotor 2.

The rotational vibration prevention device 5 includes an output gear 6 as a fixture,
It is formed from an elastic body 7 and a weight 8. The output gear 6, the elastic body 7, and the weight 8 are stacked along the thrust direction of the rotor 2, as described below.

The output gear 6 is attached by fitting its center hole into one end of the rotor shaft 3. This gear 6 is closed.

The elastic body 7 has a shape that does not cause imbalance in the rotational direction, for example, a disk shape, and is made of a rubber-like material such as acrylic foam and has a predetermined thickness. Adhesive layers 9 and 10 are attached in advance to both sides of the elastic body 7, respectively.

The adhesive layer 9.10 is formed of, for example, a double-sided adhesive sheet with adhesive material provided on both sides of the sheet. Therefore, as shown in FIG. 2, the elastic body 7 and the adhesive layers 9 and 10 are formed in a three-layer structure.

The elastic body 7 is arranged concentrically with the rotor 2 with one side thereof adhered to the end surface 6a of the output gear 6 via one of the adhesive layers (for example, the adhesive layer 9). .

The weight 8 is provided to give the rotor 2 an inertial mass. The size of the mass of this weight 8 can be arbitrarily obtained by changing the diameter and thickness, and the size of this mass depends on the torque of the stepping motor 1 and the size of the inertia of the rotor 2. This will be determined as appropriate.

The weight 8 is made of metal or non-metal, but in this embodiment, one made of a non-conductive material is used.

This weight 8 also has a shape that does not cause unbalance in the rotational direction, for example, a disk shape, and is formed to have a predetermined thickness. The maximum diameter of the weight 8 is set to be equal to or smaller than the outer diameter of the motor frame 4. Furthermore, this weight 8 is formed to have a larger diameter than the elastic body 7.

The weight 8 has an adhesive layer 10 on the other side of the elastic body 7.
The rotor 2 is bonded to the rotor 2 through the rotor 2, and is arranged concentrically with the rotor 2.

Furthermore, the stepping motor 1 equipped with the rotational vibration prevention bag gt5 configured as described above is used by being built into office equipment or the like. An example of this is shown in FIG. 3, in which reference numeral 11 is a support plate, on which the stepping motor 1 is attached so that the axis of the rotor shaft 3 is horizontal, and the output gear 6 is connected to the stepping motor 1. is meshed with a human power gear 12a of a transmission gear mechanism 12 that transmits power to a load (not shown). Further, a circuit board 13 of office equipment is arranged below the support plate 11, and various electronic components 14 are attached to the upper surface of this board 13.

Next, the operation of the above embodiment will be explained.

The stepping motor 1 is operated by applying human power pulses to the coil of a stator (not shown) and switching the excitation phase, as in the conventional case. Each time an input pulse is applied, the rotor 2 is rotated by one step angle.

In driving such a stepping motor 1, the weight 8 of the rotational vibration prevention device 5 attached to the rotor shaft 3 is
gives an inertial mass to the rotor 2. Therefore, each time the rotor 2 rotates by one step angle, the elastic body 7 made of a rubber-like material between the weight 8 and the fixture 6 attached to the rotor shaft 3 is elastically deformed. Therefore, resistance based on the elastic deformation of the elastic body 7 acts against the mutual movement of the rotor 2 and the weight 8. This resistance provides a damping force against fluctuations in the rotational speed of the rotor 2.

By applying the above-described damping force to the rotor 2, the formation of large peaks at each step is suppressed, and the angular displacement of the rotor shaft 3 is smoothly improved as shown in Fig. 4. . Therefore, the vibration of the stepping motor 1 and the noise generated therefrom can be reduced.

The rotational vibration prevention device 5 included in this motor 1 is
The fixing device 6, elastic body 7, and weight 8 are arranged in a stacked manner in the thrust direction of the rotor 2, so compared to a case where these are arranged in a stacked manner along the radial direction. , the maximum diameter of the prevention device 5, that is, the diameter of the weight 8, can be reduced.

Therefore, this prevention device 5 is suitable for use when attached to the stepping motor 1 whose motor frame 4 has a small outer diameter. In this case, the substantial outer diameter of the motor as a whole can be prevented from increasing, so that it can be installed in a narrow space of office equipment.

Moreover, the elastic body 7 and the weight 8 of the rotational vibration prevention device 5 are
Since it is attached to the output gear 6 by adhesive without using fixing devices such as screw parts, the adhesive strength decreases due to deterioration of the adhesive layers 9 and 10, and the weight 8 peels off and lands on the circuit board 13. There is a risk that it will be listed. However, even if such a situation were to occur, since the elastic body 7 and the weight 8 are non-conductive, there is no risk of short-circuiting the circuit on the circuit board 13.

Moreover, in this embodiment, the elastic body 7 is bonded as described above.
Since the preventive device 5 and the weight 8 are attached, a fixing part for fixing the preventive device 5 to the rotor shaft 3 can be omitted, and since the output gear 6 is used as a fixing device, the preventive device 5 can be attached to the rotor shaft 3. The number of points is small and the configuration is simple.

Moreover, since the elastic body 7 and the weight 8 are attached with adhesive as described above, there is no need to connect them integrally using a mold, and manufacturing is easy. not only that,
Since the elastic body 7 and the adhesive layers 9 and 10 on both sides thereof have a three-layer structure in advance, it is necessary to adhere each elastic body 7 to the end surface 6a of the output gear 6 and the weight 8 to this elastic body 7. There is no need to apply an adhesive, and the elastic body 7 can be easily bonded via the adhesive layers 9 and 10 on both sides. Therefore, the prevention device 5 can be easily attached to the rotor shaft 3.

FIG. 5 shows a second embodiment of the invention. This embodiment is an example applied to a hybrid stepping motor having an inner rotor structure. This embodiment differs from the first embodiment in the motor structure and the structure and arrangement of the rotational vibration prevention device.

The structure of the hybrid stepping motor 21 is the same as that of a conventionally known one, and will be briefly explained below.
is the stator, and on both sides there are motor frames 23 and 24.
are provided to fit each other, and these frames 23.
24 exposes the outer peripheral surface of the core of the stator 22 to the outside. Bearings 25 are attached to the center portions of the motor frames 23 and 24, and a rotor 26 is rotatably attached via these bearings 25. The rotor 26 is formed by attaching a rotor main portion 28 to the center of a rotor shaft 27. The main rotor g28 is housed inside the core of the stator 22, and is formed by adhering rotor cores 30 and 31 to both sides of a rotor magnet 29 magnetized along the axial direction of the rotor shaft 27. There is. Also,
One end of the rotor shaft 27 protrudes from one motor frame 23, and an output gear 32 is attached to the end. In such a hybrid stepping motor 21, a dead space is usually formed between the motor frame 23 and the rotor core 30, and between the motor frame 24 and the rotor core 31, respectively. By slightly increasing the axial length of the motor frame 24, the above space can be made larger.

Next, the rotational vibration prevention device 35 will be explained. This device 35 is provided using a dead space formed between the motor frame 24 and the rotor core 31. The prevention device 35 is formed of an elastic body 38 having a three-layer structure with adhesive layers 36 and 37 attached to both sides in advance, and a weight 39 that provides an inertial mass to the rotor 26. The elastic body 38 and the weight 39 of the prevention device 35 are stacked along the axial direction of the rotor 26 as described below.

The elastic body 38 has a shape that does not cause unbalance in the rotation direction, for example, a disk shape, and has a rotor shaft through hole 38 in the center thereof.
a, and is made of a rubber-like material such as acrylic foam and has a predetermined thickness. The outer diameter of this elastic body 38 is smaller than the outer diameter of the rotor main portion 28 . The elastic body 35 has one side surface bonded to the end surface of the rotor main portion 28 (in this embodiment, the end surface 31a of the rotor core 31) via one of the adhesive layers (for example, the adhesive layer 36). and is arranged concentrically with the rotor 26.

The three weights are made of metal or non-metal, and these three weights also have a shape that does not cause unbalance in the rotation direction, for example, a disk shape, and have a rotation shaft through hole 39a in the center thereof. , and is formed to have a predetermined thickness. The size of the mass of this weight 39 can be arbitrarily obtained by changing the diameter and thickness, and the size of this mass is determined by the torque of the stepping motor,
and is appropriately determined depending on the magnitude of the inertia of the rotor 26. The weight 35 is adhered to the other side surface of the elastic body 38 via an adhesive layer 37 and is arranged concentrically with the rotor 26.

In the configuration of this second embodiment as well, it is possible to obtain a damping force against rotational speed fluctuations of the rotor 26 and reduce vibration noise of the stepping motor 21 by the same effect as explained in the first embodiment. , the number of parts of the rotational vibration prevention device 35 is small and the configuration is simple, and
It can also be easily attached to the rotor 26.

Moreover, in this embodiment, since the rotational vibration prevention device 35 is provided by adhering to the end surface 31a of the rotor main portion 28, this device 3
5 can be covered by the motor frame 24. Therefore, during handling such as assembling the motor 21 to a device, no external force is applied to the rotational vibration prevention device 35 that would cause it to come off.

Since the dead space between the motor frame 24 of the inner rotor type stepping motor 21 and the end face 31a of the motor main section 28 is provided here, the prevention device 35 is installed in the motor frame 24. Compared to the case where the motor is attached to the end of the rotor shaft 27 protruding outside the frame, the axial dimension of the entire motor can be shortened.

FIG. 6 shows a third embodiment of the invention. This embodiment is an example applied to a hybrid stepping motor having an inner rotor structure. Since this embodiment differs from the second embodiment described above in the structure and arrangement of the rotational vibration prevention device, only this point will be explained below.

An end of the rotor shaft 27 opposite to the end to which the output gear 32 is attached also projects outside the motor frame 24, and a rotational vibration prevention device 41 is attached to this end. This device 41 is formed from a fixture 42, an elastic body 43, and a weight 44, which are stacked along the thrust direction of the rotor 26 as described below.

The fixture 42 has a disk shape, and its center hole is connected to the rotor shaft 27.
It is attached by fitting onto the end of the This fixture 42 has an end surface 42 along a direction perpendicular to the axial direction of the rotor shaft 27.
It has a.

The elastic body 7 has a center hole 43a in its center into which the end of the rotor shaft 27 enters, and has a shape, for example, a ring shape, that does not cause unbalance in the rotational direction.

The elastic body 43 is made of a rubber-like material such as acrylic foam and has a predetermined thickness. and elastic body 4
Adhesive layers 45 and 46 are attached in advance to both sides of 3, respectively, and these have a three-layer structure. The adhesive layers 45 and 46 are formed of, for example, double-sided adhesive sheets.One side of the elastic body 43 is adhered to the end surface 42a via one of the adhesive layers (for example, the adhesive layer 45). It is arranged concentrically with the rotor 26.

Weight 44 is provided to provide inertial mass to rotor 26. The mass of this weight 44 can be arbitrarily obtained by changing the diameter and thickness, and the mass depends on the torque of the stepping motor and the inertia of the rotor 26. This will be determined as appropriate. This weight 44 is made of metal or non-metal, but in this embodiment, one made of a non-conductive material is used. This weight 44 also has a shape that does not cause unbalance in the rotational direction, for example, a disk shape, and is formed to have a predetermined thickness.

The maximum diameter of the weight 44 is the same as that of the motor frame 23.
It is formed to be smaller than the maximum outer diameter dimension of 24. Furthermore, this weight 44 is formed to have a larger diameter than the elastic body 43.

Further, the weight 44 has an adhesive layer 46 on the other side of the elastic body 43.
The rotor 26 is attached concentrically to the rotor 26.

In the stepping motor equipped with such a rotational vibration prevention bag af41, it is possible to obtain the same effect as that described in the first embodiment, thereby achieving the intended purpose of the present invention.

Note that the present invention is not limited to the above embodiments. For example, the adhesive layer may be formed of an adhesive material such as a polymer adhesive. When an adhesive layer containing an adhesive is used, the viscosity of the adhesive functions similarly to an elastic body, so rotational vibration can be further suppressed. Of course, the adhesive layer may be formed using an adhesive that hardens after adhesion.

Furthermore, in the present invention, the adhesive layer and the elastic body do not need to have a three-layer structure in advance, and the adhesive layer and the elastic body and the weight may be attached by coating or pasting each time. .

Furthermore, it goes without saying that the present invention can be applied to various stepping motors other than the above embodiments.

[Effects of the Invention] Since the present invention is configured as described above, it has the following effects.

According to the invention of claim 1, since the elastic body and the weight are arranged in a stacked manner in the thrust direction of the rotor, the maximum diameter of the rotational vibration prevention device is reduced, and the substantial diameter of the stepping motor is reduced. In addition to being able to reduce the size in the direction, the elastic body and weight can be attached to each other by adhesive.
The rotational vibration prevention device is easy to manufacture and can be easily attached to the rotor.

Further, according to the invention of claim 2, since the weight of the rotational vibration prevention device is made of a non-conductive material, even if the weight is peeled off due to deterioration of the adhesive layer and falls onto the circuit section of the device, the weight will remain intact. will not cause a short circuit.

According to the third aspect of the invention, the rotational vibration prevention device is installed within the motor frame by utilizing the dead space between the end face of the rotor main portion and the motor frame, which is generally provided in an inner rotor type stepping motor. Since the axial dimension of the entire motor can be shortened, the elastic body and the weight will not be subjected to external forces that would cause them to be peeled off during handling of the motor.

Further, according to the fourth aspect of the present invention, the elastic body, the body and the weight can be easily bonded together through the adhesive layers on both sides of the elastic body, and the assemblability is good.

Further, according to the invention of claim 5, since the adhesive layer is an adhesive material, rotational vibration can be further reduced due to its viscosity.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a side view showing a main part in cross section, and FIG. FIG. 3 is a cross-sectional view of the elastic body, FIG. 3 is a side view showing the positional relationship between circuit components and a stepping motor disposed above them, and FIG. 4 is a diagram showing the relationship between step angle and time. FIG. 5 is a partially sectional side view of a second embodiment of the present invention. FIG. 6C is a partially sectional side view of the third embodiment of the present invention. Figures 7 and 8 show a conventional example, with Figure 7 being a partially sectional side view, Figure 8 being a perspective view of the rotational vibration prevention device, and Figure 9 being 2.26 Rotor, 3, 27 Rotor mold, 5
．． 35.41... Rotational vibration prevention device, 6... Output gear (fixing tool), 6a, 31a, 42a... End face, 7
．． 38.43... Elastic body, 8, 39.44... Weight, 38a, 39a... Rotor shaft through hole, 28... Rotor main part, 42... Fixture, 9, 10, 36 ,37゜4
5.46...Adhesive layer.

Claims (1)

[Scope of Claims] 1. In a stepping motor in which a rotational vibration prevention device is attached to the rotor, the rotational vibration prevention device is attached to an end of the rotor shaft of the rotor and is a fixture having a larger diameter than the rotor shaft. is formed of a rubber-like material to have a predetermined thickness, and one side is bonded via an adhesive layer to an end surface of the fixture along a direction perpendicular to the axial direction of the rotor shaft, so that the rotor shaft an elastic body disposed concentrically with the rotor shaft, and an elastic body formed to have a predetermined thickness and adhered to the other side of the elastic body via an adhesive layer and disposed concentrically with the rotor axis; A stepping motor with a rotational vibration prevention device, characterized in that the stepping motor is formed from a weight that provides an inertial mass to the motor. 2. The stepping motor with a rotation vibration prevention device according to claim 1, wherein the weight is made of a non-conductive material. 3. In an inner rotor type stepping motor in which a rotational vibration prevention device is attached to the rotor, the rotational vibration prevention device is formed of a rubber-like material with a predetermined thickness and a rotor shaft through hole in the center. , one side is on the end face of the rotor main part of the rotor located within the motor frame,
an elastic body that is bonded via an adhesive layer and arranged concentrically with the rotor axis of the rotor; A stepping motor with a rotational vibration prevention device, characterized in that it is formed of a weight that is adhered to the other side of the body via an adhesive layer, is arranged concentrically with the rotor shaft, and provides an inertial mass to the rotor. 4. Claim 1, 2 or 3, wherein the adhesive layers on both sides of the elastic body are attached to the elastic body in advance, and both adhesive layers and the elastic body form a three-layer structure. A stepping motor with a rotational vibration prevention device described in . 5. The stepping motor with a rotational vibration prevention device according to claim 1, 2, 3 or 4, wherein the adhesive layer is made of an adhesive material.