JPH06284682A - Stepping motor - Google Patents

Abstract

PURPOSE:To provide a stepping motor in which vibrations produced at the time of driving can be suppressed and noise produced from the mounted side with the propagation of vibrations to the mounted side can be prevented in a stepping motor. CONSTITUTION:A spring 5 is inserted between one end in the direction of an axial line of a rotor 2 and a support sober 4, and the rotor 2 is energized toward the other end in the direction of an axial line by the spring 5. The other end in the direction of an axial line of the rotor 2 is abutted on a motor case 1 through a thrust bearing 7. The spring 5 is so coupled to the rotor 2 as to rotate it together with the rotor 2. Further, the spring 5 is rotatably supported in the case 1 through a ball bearing 6. A cylindrical case 8 is provided in the outer circumferential part of the spring 5 to accommodate the spring 5 within the case 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor, and more particularly, to a stepping motor capable of suppressing vibration generated during driving.

[0002]

2. Description of the Related Art In general, a stepping motor includes a stator having a plurality of multi-layer windings having a minute pitch and separated from each other, and a salient pole-shaped rotor housed inside the stator and having a slight pitch deviation from the stator. By sequentially exciting the windings of the stator, the salient poles of the rotor are sequentially attracted and rotated, and an output with a rotation angle proportional to the number of input pulses is obtained and the input pulse Since the output rotation speed proportional to the frequency is obtained and the position accuracy is improved, it is used in various devices that require positioning accuracy.

[0003]

However, in such a conventional stepping motor, since the rotor is rotated by the pulse input, the vibration is generated. In particular, the amplitude or frequency of the input pulse varies depending on the component accuracy even in the same motor, and there are cases where the same motor is used at two or more types of rotational speeds, so it is difficult to suppress the generated vibration. This vibration is transmitted to the various devices to which the motor is attached,
There was a problem that abnormal noise was generated.

Therefore, the present invention provides a stepping motor capable of suppressing the vibration generated at the time of driving and preventing the transmission of the vibration to the mounted side and the generation of noise from the mounted side. It is an object.

[0005]

The invention according to claim 1 is
In order to solve the above problems, in a stepping motor including a motor case and a rotor rotatably supported in the case, the stepping motor is interposed between one axial end of the rotor and the inner wall of the motor case. , And a spring for urging the rotor toward the other end in the axial direction.

In order to solve the above-mentioned problems, the invention according to claim 2 is characterized in that the other axial end portion of the rotor contacts the motor case via a thrust bearing. In order to solve the above problems, the invention according to claim 3 is characterized in that the spring is connected to a rotor and rotates together with the rotor. In order to solve the above-mentioned problems, the invention of claim 4 is characterized in that the motor case inner wall side of the spring is rotatably supported by the motor case by a ball bearing.

In order to solve the above-mentioned problems, the invention of claim 5 has a variable means for varying the urging force of the spring. In order to solve the above-mentioned problems, the invention according to claim 6 is characterized in that a cylindrical case is provided on an outer peripheral portion of the spring, and the spring is housed in the case.

[0008]

According to the first aspect of the invention, a spring is interposed between one end of the rotor in the axial direction and the inner wall of the motor case, and the spring urges the rotor toward the other end of the axial direction. Therefore, when the rotor rotates, the spring presses the rotor toward the case in the axial direction, and vibration generated when the motor is driven is suppressed. As a result, vibration is not transmitted from the motor to the mounted side and noise is not generated from the mounted side.

According to the second aspect of the invention, the other axial end of the rotor is in contact with the motor case via the thrust bearing. Therefore, the friction between the rotor and the case is reduced, and the rotor is stably rotated. As a result, the vibration generated from the motor is further suppressed. In the invention according to claim 3, the spring is connected to the rotor and is rotated together with the rotor. Therefore, the mass of the rotor is increased by the amount of the spring, and the rotor is surely biased by the spring. As a result, the vibration generated in the motor is further suppressed.

According to the fourth aspect of the invention, the inner wall side of the spring of the motor case is rotatably supported by the motor case by the ball bearing. Therefore, the resistance between the motor case and the spring is reduced when the rotor is rotated, and the connecting portion does not generate heat. As a result, the rotation of the rotor is not hindered by the spring, the spring is used for a long period of time, and the motor is stably driven for a long period of time.

According to a fifth aspect of the invention, there is provided variable means for varying the biasing force of the spring. Therefore,
By varying the spring force according to the rotation speed of the rotor, the natural vibration point of the motor is changed, and the vibration is sufficiently suppressed even when the rotation speed of the motor changes.
In the invention according to claim 6, a cylindrical case is provided on the outer peripheral portion of the spring, and the spring is housed in the case. Therefore, when the spring rotates, the spring does not swing due to centrifugal force, and a specific value of natural vibration is prevented.

[0012]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a diagram showing an embodiment of a stepping motor according to the present invention. First, the configuration will be described. In FIG. 1, 1
Is a motor case, and the rotor 2 is housed in the case 1. Further, as is well known, a stator having a plurality of multi-layer windings having a predetermined pitch and separated from each other around the rotor 2, a harness for inputting a pulse signal of a predetermined frequency to each winding of the stator, and the like. Is provided. The rotor 2 has a salient pole shape with a pitch slightly different from the stator, and by sequentially exciting the stator, the salient poles of the rotor 2 are sequentially attracted and rotated. In the present embodiment, the stator and the like are not shown in the drawings in order not to obstruct the description.

One end of the rotor shaft 2a in the axial direction of the rotor 2 is supported by the support member 4 via the metal bearing 3a, and the other end of the rotor shaft 2a in the axial direction rotates to the case 1 via the metal bearing 3b. It is supported freely. A spring 5 is interposed between the support member 4 and the rotor 2. One end of the spring 5 is fixed to the support member 4 and the other end is connected to the rotor 2. Urges the rotor 2 toward the other end in the axial direction and rotates with the rotor 2.

A ball bearing 6 is provided on the outer peripheral portion of the support member 4. The ball bearing 6 is provided slidably in the direction of the arrow on the inner peripheral surface of the case 1, and the support member 4 is provided. 4 is rotatably supported on the case 1.
In this embodiment, the support member 4 is regarded as the inner wall of the motor case 1 referred to in the claims. Also, the rotor 2
A thrust bearing 7 is interposed between the other axial end of the metal bearing 3 b and the metal bearing 3 b, and the rotor 2 is in contact with the case 1 via the bearing 7. A cylindrical case 8 is provided on the outer peripheral portion of the spring 7, and the spring 5 is housed in the case 8.

On the other hand, a cylindrical moving member 9 is provided between the case 1 and the ball bearing 6, and this connecting member 9 has a screw 10 screwed into the case 1, and the screw 10 rotates. Therefore, the rotor 2 is moved closer to and away from the rotor 2. The connecting member 9 biased by the spring 5 comes into contact with the tip of the connecting member 9.
The biasing force of the spring 5 can be varied by bringing the support member 4 and the ball bearing 6 close to the rotor 2 side as the rotor 10 rotates. The connecting member 9 and the screw 10 constitute a variable means.

In this embodiment having such a structure, a spring 5 is interposed between one end of the rotor 2 in the axial direction and the support member 4, and the spring 5 moves the rotor 2 toward the other end in the axial direction. Since the rotor 2 is biased, the rotor 2 can be pressed against the case 1 in the axial direction by the spring 5 when the rotor 2 rotates, and it is possible to suppress the occurrence of vibration when the motor is driven. As a result,
It is possible to prevent vibration from being transmitted to the mounted side and noise from being generated from the mounted side.

Further, since the other axial end portion of the rotor 2 is brought into contact with the motor case 1 via the thrust bearing 7, the friction between the rotor 2 and the case 1 can be reduced and the rotor 2 can be reduced. It can be rotated stably. As a result, the vibration generated from the motor can be further suppressed. Further, since the spring 5 is connected to the rotor 2 so as to rotate together with the rotor 2,
The mass of can be increased by the amount of the spring, and the rotor 2 can be surely biased by the spring 5, so that the vibration generated in the motor can be further suppressed.

Further, since the spring 5 is rotatably supported by the case 1 via the ball bearing 6, the resistance between the motor case 1 and the spring 5 can be reduced when the rotor 2 rotates and the connection can be achieved. It is possible to prevent the part from generating heat. As a result, the rotation of the rotor 2 can be prevented from being hindered by the spring 5, the spring 5 can be used for a long time, and the motor can be stably driven for a long time. it can.

Further, the urging force of the spring 5 is applied to the connecting member 9
And, since it is varied by the screw 10, the spring force can be varied according to the rotation speed of the rotor 2,
The characteristic vibration point of the motor can be changed. As a result, vibration can be sufficiently suppressed even when the rotation speed of the motor changes. Further, since the cylindrical case 8 is provided on the outer peripheral portion of the spring 5 and the spring 5 is housed in the case 8, it is possible to prevent the spring 5 from swinging due to centrifugal force when the spring 5 rotates. It is possible to prevent a constant value of natural vibration.

[0020]

According to the first aspect of the invention, the rotor can be pressed against the case in the axial direction by the spring when the rotor rotates, and the vibration can be suppressed when the motor is driven. it can. As a result, it is possible to prevent the transmission of vibration to the mounted side and the generation of noise from the mounted side.

According to the second aspect of the present invention, the friction between the rotor and the case can be reduced, and the rotor can be stably rotated. As a result, the vibration generated from the motor can be further suppressed. According to the third aspect of the present invention, the mass of the rotor can be increased by the amount of the spring, and the rotor can be surely biased by the spring, so that the vibration generated in the motor can be further suppressed. .

According to the fourth aspect of the present invention, it is possible to reduce the resistance between the motor case and the spring when the rotor rotates, and to prevent the connecting portion from generating heat. As a result, the rotation of the rotor can be prevented from being hindered by the spring, and the spring can be used for a long period of time.
The motor can be driven stably over a long period of time.

According to the fifth aspect of the invention, the spring force can be varied according to the rotational speed of the rotor, and the natural vibration point of the motor can be varied. As a result, vibration can be sufficiently suppressed even when the rotation speed of the motor changes. According to the sixth aspect of the invention, it is possible to prevent the spring from swinging due to centrifugal force when the spring rotates, and also to prevent natural vibration of a constant value.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a stepping motor according to the present invention.

[Explanation of symbols]

 1 Motor Case 2 Rotor 4 Support Member (Inner Wall) 5 Spring 6 Ball Bearing 7 Thrust Bearing 8 Cylindrical Case 9 Connecting Member (Variable Means) 10 Screw (Variable Means)

Claims (6)

[Claims] 1. A stepping motor comprising a motor case and a rotor rotatably supported in the case, the stepping motor being interposed between one axial end of the rotor and an inner wall of the motor case, A stepping motor having a spring biased toward the other end in the axial direction. 2. The stepping motor according to claim 1, wherein the other axial end portion of the rotor contacts the motor case via a thrust bearing. 3. The stepping motor according to claim 1, wherein the spring is connected to the rotor and rotates together with the rotor. 4. The stepping motor according to claim 3, wherein an inner wall side of the spring of the motor case is rotatably supported by the motor case by a ball bearing. 5. The stepping motor according to any one of claims 1 to 4, further comprising a varying unit that varies a biasing force of the spring. 6. The stepping motor according to claim 1, wherein a cylindrical case is provided on an outer peripheral portion of the spring, and the spring is housed in the case.