JPS63220742A - Motor - Google Patents

Abstract

PURPOSE:To generate a slip on a contact surface between a rotating member and a back yoke for preventing burning of a motor when an excessive load is applied to an apparatus. by bringing said rotating member and back yoke into contact with each other and by transmitting a rotary driving force to the rotating member via said contact surface. CONSTITUTION:When a driving current is caused to flow through a stator winding 3, a rotor magnet 1 and a back yoke 2 integrally start rotation. Because a thrust attraction force is generated between the rotor magnet 1 and a printed wiring board 3', a pressure is generated in a contact surface A of a rotating member 4 and the back yoke 2. Therefore, a rotary driving force proportional to a friction coefficient and a thrust attraction force between the back yoke 2 and the rotating member 4 is transmitted to the rotating member 4. When an excessive load is applied, the back yoke 2 and the rotating member 4 slip on each other.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to motors used in various electronic devices.

BACKGROUND OF THE INVENTION In recent years, motors have been increasingly used in various electronic devices for the purpose of increasing performance and multifunctionality, and video tape recorders (hereinafter abbreviated as VTR), for example, are no exception. Taking a VTR as an example, various operation modes such as recording/playback, stop, and special playback are required.Switching between these various operation modes is performed by a motor, a belt, a gear, etc., and a cam for switching operation modes, etc. This is done by driving −
It is commonly practiced.

FIG. 3 shows a cross-sectional view of a conventional motor. In FIG. 3, 1 is a rotor magnet magnetized into multiple poles in the axial direction, 2 is a back yoke made of a magnetic material, and 3 is a printed arrangement made of a magnetic material! l! The i1 board 3 is a stator winding fixed on the printed wiring board 3' by adhesive or the like. A rotor magnet I is fixed to the back yoke 2 by adhesive or the like, and a pulley groove 5' for winding the belt 10 is provided. Further, the back yoke 2 is press-fitted onto a shaft 6, and the shaft 6 is rotatably supported by a bearing 7 provided on a chassis board 8.

Further, an operation mode switching cam (not shown) is coupled to the belt 10 via a speed reduction mechanism (not shown).

Now, when a drive current is applied to the stator winding 3, the rotor magnet l and the back yoke 2 start rotating integrally on the shaft 6 due to the biasing of the stator winding 3. Therefore, pulley groove 5
The rotational driving force is transmitted to the speed reduction mechanism by the belt lO wound around '.

If the operation mode switching cam connected to the belt 10 is locked due to an abnormal load, the belt 10 will slip in the boob groove 5'', preventing excessive load from being applied to the motor and preventing the mechanism from operating. It is possible to prevent damage etc.

Problems to be Solved by the Invention However, in the above configuration, the belt 10
Therefore, in order to extract the rotational driving force to the outside, the belt 1
It is necessary to increase the cross-sectional area of the belt 10 (and to increase the tension of the belt IO. In this case, due to aging, the rotational driving force that can be transmitted by the belt 10 decreases). there were.

Further, if the rotational driving force that can be transmitted by the belt 10 cannot be increased, it is necessary to increase the reduction ratio in the reduction mechanism. In this case, there is a problem that the size of the device increases.

Furthermore, when the belt 10 is not used and an output means such as a timing belt or a gear transmission mechanism is used, a relatively large value of driving force can be transmitted, and no decrease in the rotary driving force that can be transmitted due to changes over time has been observed. No, however in this case,
If the operation l1ll-like switching cam etc. is locked due to some reason such as an abnormal load, the abnormal load will be applied to the motor, causing a problem such as burnout of the motor or damage to the speed reduction mechanism.

Means for Solving the Problems Technical means of the present invention for solving the above problems include a back yoke that holds rotor magnets magnetized with multiple poles in a plane, and 7. a printed wiring board made of a magnetic material arranged to face a plane; a rotating member having a rotational driving force extraction means for extracting the rotational driving force to the outside of the motor and abutting the back yoke or the rotor magnet at one end plate in the axial direction; the rotor magnet and the printed wiring board; a thrust holding member that holds a thrust suction force generated between the two through the rotating member, and the rotating member and the back yoke can rotate independently of each other about the axis of rotation. The effect of this technical means is as follows.

That is, a bank yoke holding rotor magnets magnetized with multiple poles in a plane as described above, a printed distribution board made of a magnetic material arranged so as to face the magnetized plane of the rotor magnets, A rotational driving force extraction means for extracting rotational driving force is provided outside the motor, and a rotating member that contacts the back yoke or the rotating magnet at one end surface in the axial direction, and the rotor magnet and the printing arrangement board. and a thrust holding member that holds the thrust suction force generated between the rotary member and the rotary member, and the rotary member and the back yoke are configured to rotate independently of each other about the shaft. By configuring the rotor to transmit the rotational driving force to the rotating member at the contact surface by the thrust attraction force generated between the printed distribution board and the rotor magnet, an excessive load is not applied. However, since the motor slips on the contact surface, it is possible to prevent burnout of the motor and damage to the speed reduction mechanism, etc.

Therefore, the means for extracting rotational driving force from the motor to the outside is no longer limited to the belt, so the rotational driving force that can be extracted from the motor can be increased, which not only reduces the size of the reduction mechanism but also reduces the size of the entire device and improves reliability. This makes it possible to improve performance, reduce weight, and reduce costs.

EXAMPLE Hereinafter, a motor according to an example of the present invention will be explained based on the drawings. FIG. 1 is a cross-sectional view of a motor in one embodiment of the present invention.

In Fig. 1, 1 is a rotor magnet magnetized into multiple poles in the axial direction, 2 is a back yoke made of a magnetic material, 3 is a stator winding, 3'' is a printed wiring board made of a magnetic material, and 4° is a rotating member.A rotor magnet 1 is fixed to a back yoke 2 by adhesive or the like.The back yoke 2 is press-fitted onto a shaft 6, and the shaft 6 is provided on a chassis board 8. It is rotatably held by a bearing 7.

Here, the rotating member 4° is provided with a gear portion 5 for extracting rotational driving force to the outside, and this rotating member 4° is supported on a shaft 6 by a periphery bearing 7′. Therefore, the back yoke 2 and the rotating member 4' are supported so that they can rotate independently of each other about the shaft 6. Further, the back yoke 2 and the rotating member 4' are in contact with each other at one end surface A in the axial direction. The thrust attraction force generated between the rotor magnet 1 and the printed wiring board 3'' is held by the thrust holding member 50 via the rotating member 4''.

In addition, the gear portion 5 is connected to a deceleration mechanism (not shown).
A cam (not shown) for switching operation mode is coupled thereto.

Next, the operation of this embodiment will be explained.

At this point, when a drive current is applied to the stator winding 3, the rotor magnet 1 and the back yoke 2 start rotating integrally on the rotating shaft due to the biasing of the stator winding 3. Here, since a thrust attraction force is generated between the rotor magnet 1 and the printed wiring board 3', the back yoke 2 is attracted in the direction of the printed wiring board 3°, and the rotation member 4° and the back yoke 2 Pressure is generated at the contact surface A. Therefore, a rotational driving force proportional to the friction coefficient between the back yoke 2 and the rotating member 4° and the thrust attraction force is transmitted to the rotating member 4°.

That is, the rotational driving force is transmitted by the gear portion 5 to the operation mode switching cam via the reduction mechanism.

In this embodiment, the magnetic circuit configuration of the motor is the same as before, so the motor characteristics do not change. However, since the gear portion 5 is used as a means for extracting the rotational driving force to the outside, the belt is not changed as in the conventional case. It becomes possible to extract a larger value of rotational driving force than if it were used. Therefore, since the reduction ratio of the reduction mechanism can be reduced, it is possible to reduce the size, cost, and weight of the reduction mechanism.

Furthermore, even though the gear section 5 is used as a means for extracting rotational driving force, even if an excessive load is applied, the bank yoke 2 and the rotating member 4' will slip against each other, resulting in motor burnout and deceleration. Damage to mechanisms etc. is prevented.

As described above, according to this embodiment, it is possible to provide a highly reliable, low-cost, and high-performance motor with a very simple configuration.

Next, a second embodiment of the present invention will be described.

FIG. 2 is a cross-sectional view of the motor in this embodiment.

In FIG. 2, 1 is a rotor magnet magnetized into multiple poles in the axial direction, 2 is a bank yoke made of a magnetic material, 3 is a stator winding, 3' is a printed wiring board made of a magnetic material, and 4' is a rotating member. A rotor magnet 1 is fixed to the back yoke 2 by adhesive or the like. The shaft 6, which is the center of rotation, is rotatably supported by a bearing 7' provided on the chassis board B, and a screw 2 screwed into the chassis board 8.
0, it is restricted from moving in the thrust direction. The back yoke 2 is rotatably supported on a shaft 6 by a bearing 7.

On the other hand, a printed wiring board 3'' is disposed so as to face the magnetic pole surface of the rotor magnet 1, and the stator winding 3 is disposed on the rotating member 4°.A gear portion 5 for extracting rotational driving force to the outside is provided on the rotating member 4°.Here, the rotating member 4' is press-fitted into the shaft 6, and the rotor The magnet l and the rotating member 4° are in contact with each other at one end surface A in the axial direction via a felt ring 9 bonded to the rotor magnet l.

In addition, the gear portion 5 is connected to a deceleration mechanism (not shown).
A cam (not shown) for switching operation mode is coupled thereto.

Next, the operation of this embodiment will be explained.

Now, when a drive current is applied to the stator winding 3, the rotor magnet 1 and the back yoke 2 start rotating integrally about the shaft 6 due to the biasing of the stator winding 3. Here, since a thrust attraction force is generated between the rotor magnet 1 and the printed wiring board 3'', the rotor magnet 1 is attracted in the direction of the rotating member 4'', and the rotation member 4'' and the ring 9 are attracted to each other. Pressure is generated at the contact surface A. That is, a rotational driving force proportional to the friction coefficient between the ring 9 and the rotating member 4° and the thrust suction force is transmitted to the rotating member 4''. Therefore, the rotational driving force is transmitted by the gear portion 5 to the operation mode switching cam via the reduction mechanism.

In this embodiment, since the gear portion 5 is used as a means for extracting the rotational driving force to the outside, it is possible to extract a larger value of rotational driving force than when a belt is used as in the past. become.

Furthermore, even though the gear section 5 is used as a means for extracting rotational driving force, even if an excessive load is applied to the operation mode switching cam, the ring 9 and the rotating member 4' will slip against each other, so the motor This prevents burnout and damage to the deceleration mechanism, etc.

In addition, since the felt ring 9 is used on the contact surface, it has a long life and stable temperature characteristics, and even if there is surface runout of the end surface that the rotating member 4 is in contact with, it can be transmitted. The rotational driving force remains constant.

Also, the amount of air gap between the printed wiring board Fi3' and the rotor magnet 1 is as follows:
Since it can be set to any value using the screw 20, the thrust suction force can be changed to any value. That is, it becomes possible to set the transmittable rotational driving force to an arbitrary value.

In this embodiment, the ring 9 is made of felt, but the present invention is not limited to this, and may be made of, for example, oil-impregnated resin.

Further, the means for adjusting the amount of air gap between the magnetic pole surface of the rotor magnet 1 and the printed wiring board 3' is not limited to the screw 20. For example, a plunger (not shown) or a linear motor (not shown) can be used. ) etc. are mounted so that they can rotate integrally with the rotating member 4 degrees, and power is supplied to these actuators using known means such as brushes (not shown) and slip rings (
There is no problem even if the axial position of the printed wiring board 3' with respect to the rotor magnet is set at an arbitrary location.

Further, the rotor magnet 1 does not necessarily have to be fixed to the back yoke 2 in a flat plane, but may be a cylindrical surface on the inner circumferential side or the outer circumferential side.

Further, the means for extracting the rotational driving force to the outside may be other than gears, such as a timing belt, or the rotating member 4° may directly drive the cam for switching the operation mode.

In the first and second embodiments, a predetermined brake torque can be applied to the motor by locking the operation mode switching cam etc. with a locking means (not shown), so there is no possibility of damage to the mechanism. Another effect is that the motor can be stopped without causing noise, vibration, or the like.

Furthermore, an example has been described in which the shaft serving as the center of rotation is rotatably supported on the chassis board, but it goes without saying that this can also be achieved in a case where the shaft is press-fitted into the chassis board.

In addition, in the first and second embodiments, the rotational drive force extraction means was attached to rotate integrally with the rotating member 4', but the second rotational drive force extracting means rotates integrally with the back yoke. A configuration may also be adopted in which a force extraction means is provided so that two types of output can be simultaneously extracted from one motor.

Furthermore, in the first and second embodiments, the motor has V
Although it was explained as a motor for switching the operation mode of the TR,
It is clear that the present invention is not limited to such usage, and can be used, for example, in a VTR capstan motor, reel motor, etc.

Effects of the Invention The present invention comprises: a back yoke that holds a rotor magnet magnetized with multiple poles in a plane; a printed wiring board made of a magnetic material disposed so as to face the magnetized plane of the rotor magnet; a rotating member having a rotational driving force extraction means for extracting rotational driving force to the outside of the motor and abutting the back yoke or the rotor magnet at one end surface in the axial direction; the rotor magnet and the printed wiring board; and a thrust holding member that holds the thrust suction force generated between the rotary member and the rotary member via the rotary member, and the rotary member and the back yoke rotate independently of each other about the axis of rotation. By transmitting the rotational driving force to the rotating member through the contact surface by the thrust suction force, even if an excessive load is applied from the output side, the contact surface Since the motor slips, it is possible to prevent burnout of the motor and damage to the reduction mechanism, etc., and it is possible to provide an inexpensive and highly reliable motor.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a motor according to one embodiment of the present invention, FIG. 2 is a cross-sectional view of a motor according to another embodiment of the present invention, and FIG.
The figure is a cross-sectional view of a motor in a conventional example. 1... Rotor magnet, 2... Back yoke, 3... Stator winding, 4'... Rotating member, 5...・Gear part, 5゛...Pulley groove, 6...Shaft, 7.7゛...Bearing, 8
...Chassis board, 9...Ring, 1
0...Belt. Name of agent Patent attorney Toshio Nakao Idiot 1 person 1--1st round) Gokumen 2-1-Bavuk York 3--I! I fixed) each gk 8-1-shi r-shi, Xa lU Figure 3

Claims (3)

[Claims] (1) A shaft, a rotor magnet magnetized with multiple poles on a plane, a rotor magnet holding member that rotates integrally with the rotor magnet around the shaft, and a magnetized rotor magnet. a substrate made of a magnetic material and arranged to face a plane, a stator winding arranged in a magnetic space formed by the substrate and the rotor magnet, and the rotor magnet holding member or the rotor magnet. a rotating member that contacts a rotor magnet at one end surface in the axial direction and is supported coaxially with the rotor magnet holding member so as to be able to rotate independently of the rotor magnet holding member; and this rotating member. a rotational driving force extraction means that rotates integrally with the rotor magnet and extracts the rotational driving force to the outside; and a thrust force retainer that holds the thrust attraction force generated between the rotor magnet and the substrate via the rotating member. A motor characterized by comprising a member. (2) The motor according to claim (1), characterized in that a sliding member is disposed between the rotating member and the contact surface of the rotor magnet holding member or the rotor magnet. (3) The motor according to claim (1), further comprising variable means that can change the amount of air gap between the rotor magnet and the substrate to an arbitrary value.