JPH0217922B2 - - Google Patents

Abstract

PURPOSE:To freely adjust the load of rotary torque and facilitate momentary switching of loading condition by utilizing a friction force generated between a permanent magnet and a solenoid coil. CONSTITUTION:An iron core 5 is attracted by a permanent magnet 2 under the condition that the power is not supplied to a coil 7 and therefore it is necessary for rotating a load shaft 1 to supply a rotating force which exceeds a friction force due to a contact pressure between the end surface of iron core 5 and that of a bearing 3. A friction force increases by exciting the solenoid coil so that the magnetic flux is generated in the same direction as the magnetic flux generated by the magnet 2 and a larger rotating force is required in order to dominate such friction force. On the contrary, a friction force can gradually be reduced and the condition where friction force is zero can be formed by exciting the solenoid coil so that the magnetic flux is generated in such a direction as cancelling the magnetic flux generated by the magnet 2. Moreover, the iron core 5 can be moved toward a bearing 4 by exciting the solenoid coil in such a direction as cancelling the magnetic flux generated by the magnet 2.

Description

Detailed Description of the Invention (Technical Field) The present invention is a variable rotational load solenoid that has a clutch function and can adjust the rotational load, and more specifically, uses a permanent magnet and a solenoid coil to create an electromagnetic connection between parts. The present invention relates to a rotary load variable solenoid with a clutch that can freely adjust the rotary load torque by utilizing the frictional force generated by the clutch, and can instantly disconnect the load generation state.

(Background of the Invention) Appropriate loads and brakes are often required in rotating mechanisms such as precision machines, office machines, and consumer appliances.

For example, the tape can be fed more smoothly by applying an appropriate brake torque or load to the reel on the supply side using a magnetic tape feeding mechanism or the like.

Also, this load is not uniform, and if it is possible to make it small at the beginning of supply and increase it as it approaches the end of supply, it is possible to always feed in the optimal state and to minimize the electric power of the motor that supplies the power. be able to. The same can be said about automatic film advance and automatic rewind in cameras, which have recently become commonplace.

However, in reality, there is no simple device that can provide such motion, so a load is created using a friction force generated using a spring. Such a load is constant and cannot be changed from moment to moment. Another problem is that over a long period of time, the state of friction changes and the load changes.

In large tape recorders and the like, a configuration is used in which motors are arranged on the supply side and the take-up side, each motor is alternately loaded, and the degree of the load is controlled. However, such a configuration is large-scale and either increases the size of the entire device or can only be used for devices that are inherently large.

(Objective of the Invention) The object of the present invention is to provide a compact device that can arbitrarily adjust the rotational load, instantly connect or disconnect the load generating state, and extract the mechanical displacement when the load is disconnected. An object of the present invention is to provide a rotary load variable solenoid with a clutch.

(Structure of the Invention) In order to achieve the above object, a rotary load variable solenoid with a clutch according to the present invention includes first and second magnetic bearings, and is magnetized in the axial direction and provided on the outer periphery of the first bearing. a cylindrical permanent magnet, a non-magnetic load shaft that is rotatably supported by the first and second bearings, and a load shaft that is integrally provided with the load shaft and is rotatable between the bearings. A cylindrical iron core made of a magnetic material and having a length shorter than the distance between the first and second bearings, and provided on the outer periphery of the iron core, the first bearing, the permanent magnet, and the second bearing. a bobbin, a magnetic disk provided in the middle of the bobbin in a plane perpendicular to the load axis, a solenoid coil consisting of a coil wound on both sides of the disk, and the first bearing; The permanent magnet, the second bearing, and the yoke that covers the outer periphery of the solenoid coil reduce friction between the iron core and the first bearing by adjusting the contact pressure between the iron core and the bearing using a current flowing through the coil. By adjusting the torque necessary to rotate the load shaft, a magnetic flux of a certain value or more in the opposite direction to the magnetic flux generated by the permanent magnet is generated to move the iron core in the direction of the second bearing. It is configured.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 is a diagram showing an embodiment of a rotary load variable solenoid with a clutch according to the present invention, and is partially cut away along a plane including the central axis.

FIG. 2 is a partially cutaway view of the embodiment taken along a plane perpendicular to the axis.

This embodiment is designed with the idea of automating the assembly in mind, and allows assembly based on the inner diameter of the bobbin 8 of the solenoid coil. The bobbin 8 is formed by assembling a lower bobbin 8A and an upper bobbin 8B, and a magnetic disc 6 is sandwiched between the opposing flanges of each bobbin, and the lower bobbin 8A is fitted into the upper bobbin 8B to be integrated.

A coil 7A is wound around the lower bobbin 8A, and a coil 7B is wound around the upper bobbin 8B. These coils are connected in series and connected to pins 10 and the like provided on the lower bobbin A.

A cylindrical permanent magnet 2 is attached to the first bearing 3 made of magnetic material.
are fitted and integrated.

This cylindrical permanent magnet 2 is magnetized in the axial direction.

This assembly of the bearing 3 and permanent magnet is inserted and fixed into the lower bobbin 8A.

The second bearing 4 made of magnetic material is fitted into the upper bobbin 8B.

A cylindrical magnetic core 5 is integrally provided on the non-magnetic load shaft 1 . The outer diameter of this iron core 5 is smaller than the minimum inner diameter of the bobbin 8 (see Fig. 2),
When the load shaft 1 is supported by the first and second bearings 3 and 4, it can rotate together with the shaft in the space within the bobbin 8.

The axial length of the iron core 5 is smaller than the distance between the end face of the first bearing 3 and the end face of the second bearing 4, and the iron core 5 and the load shaft are movable in the axial direction. Each yoke 9 has a yoke cylindrical portion 9 made of magnetic material.
A, a yoke lower lid part 9B, and a yoke upper lid part 9C.

The flange of the bobbin 8 and the magnetic disk 6 are inserted into the yoke cylindrical portion 9A so as to be in contact with the inner periphery thereof.

A yoke upper lid part 9C is fitted into the upper end surface of the yoke cylindrical part 9A, and a yoke lower lid part 9B is fitted into and fixed to the lower end surface.

The lower surface of the yoke upper lid portion 9C is the second bearing 4.
A relief hole for escaping the boss portion of the second bearing 4 and an escape hole for escaping the load shaft 1 are provided at the center.

A screw is provided on the outer periphery of the boss portion of the yoke upper lid portion 9C, and can be used to fix the solenoid to the mechanism.

The upper surface of the yoke lower lid portion 9B is brought into contact with the surface of the permanent magnet 2, and the first bearing 3 is located in the center.
An escape hole is provided to escape the boss part. This escape hole was intentionally provided to prevent short-circuiting of the magnetic path of the permanent magnet 2.

The main magnetic circuit when the iron core is in the position shown in FIG. 1 and no current is supplied to the coil 7 is as follows.

N pole of permanent magnet 2 → first bearing 3 → iron core 5 → magnetic disk 6 → cylindrical part 9A of yoke → lower cover part 9B of yoke → S pole of permanent magnet 2 Iron core 5 moves upward in Fig. 1 The main magnetic circuit when the upper end surface of the iron core 5 is in contact with the second bearing is as follows.

At this time, a current is supplied to the coil 7 to generate a magnetic flux in a direction that cancels out the magnetic flux generated by the permanent magnet 2.

N pole (lower side) of coil 7B → cylindrical part 9 of yoke
A → Magnetic disk 6 → Iron core 5 → Second bearing 4 → Upper cover part 9C of yoke → Cylindrical part 9A of yoke → Coil 7B
S pole (upper side) In the device with the above configuration, even when the coil 7 is not energized, the iron core 5 is attracted by the permanent magnet 2 and the first
is attracted to the surface of the bearing 3.

Therefore, in order to rotate the load shaft 1, it is necessary to supply a rotational force that overcomes the frictional force caused by the contact pressure between the end face of the iron core 5 and the end face of the first bearing 3. If the solenoid coil is excited to generate magnetic flux in the same direction as the magnetic flux generated by the permanent magnet 2, the frictional force will increase, and a larger rotational force will be required to overcome the friction.

Contrary to the above, if the solenoid coil is excited to generate magnetic flux in a direction that cancels out the magnetic flux generated by the permanent magnet 2, the frictional force will gradually decrease, and finally a state of zero friction can be achieved.

Furthermore, if the solenoid coil is excited to generate magnetic flux in a direction that cancels the magnetic flux generated by the permanent magnet 2, the iron core 5 is moved in the direction of the second bearing 4.

FIG. 3 is a graph for explaining the operating characteristics of the variable load solenoid with a clutch configured as described above. The vertical axis shows the torque (gram force/cm) required to rotate the load shaft on a logarithmic scale, and the horizontal axis shows the voltage supplied to the solenoid coil. The curve shows the operating characteristics of the example.

Approximately 16 g/cm of torque is required to rotate the load shaft without energizing the solenoid coil, which generates a voltage in the forward direction (direction that generates magnetic flux in the same direction as the permanent magnet), and When the torque is increased, 19g/cm at 1V, 10V
It weighs approximately 40 grams/cm.

When a reverse voltage is applied, a torque of 1 gram force/cm can be created at 5.5V.

When the current is further increased, a repulsive force is generated in the iron core 5 against the polarity of the permanent magnet, and the iron core 5 is moved upward from the state shown in FIG.

If we connect the coil of the device to a voltage that changes instantaneously between +6V and -6V, it will provide a load torque of approximately 30 g-force cm when +6V is applied, and when -6V is applied. When the iron core 5
and the load shaft 1 moves upward in FIG. Therefore, for example, if the load shaft is connected to a device (not shown) at a +6V position, it can be moved to another position and detached from the device at a -6V position.

Conversely, when changing from -6V to +6V, a load of about 30 grams/cm can be instantaneously coupled with this movement.

(Modifications) Various modifications can be made to the embodiments described in detail above within the scope of the present invention.

By inserting thin materials with different coefficients of friction between the first bearing 3 and the iron core 5, the load range can be changed.

The curve in Figure 3 shows the characteristics when a synthetic resin disc with a low coefficient of friction is inserted.

It can be seen that the torque has decreased significantly. The load torque when no current is supplied is 5 grams
cm. If 2V is applied in the opposite direction, the torque can be increased to 1g/cm.

Further, by increasing the current in the opposite direction, the iron core can be moved upward.

By leading out the lead wires from the upper coil 7B and the lower coil 7A in a three-terminal structure and selectively operating one or both, more diverse operations can be achieved.

(Effects of the Invention) As described above in detail, the rotary load variable solenoid with a clutch according to the present invention can freely adjust the load torque using the solenoid current. Therefore, it is also possible to automatically control the load torque by configuring a control circuit loop including this rotary load variable solenoid.

Furthermore, since the structure is simple, the entire device can be made compact.

The length of the cylindrical part of the yoke of the above-mentioned example device is 22
mm, and the diameter of the yoke is 19 mm, making it very small.

Furthermore, the electric current can cause the core to move, and this movement can be used to control external mechanisms, such as switching other clutches.

Therefore, it can be widely applied to optical machines, office machines, audio equipment, video equipment, etc.
Furthermore, since the solenoid coil is shielded by the yoke, leakage magnetic flux is prevented from occurring.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating an embodiment of a rotary load variable solenoid with a clutch according to the present invention, partially cut away along a plane including a central axis. Second
The figure is a partially broken view of the embodiment taken along a plane perpendicular to the axis. FIG. 3 is a graph for explaining the operation of the rotary load variable solenoid with clutch. 1... Load shaft, 2... Permanent magnet, 3... First bearing, 4... Second bearing, 5... Iron core, 6... Magnetic disc, 7... Coil, 7A... Bottom coil, 7
B...Upper coil, 8...Bobbin, 8A...Lower bobbin, 8B...Upper bobbin, 9...Yoke, 9A...
Yoke cylindrical part, 9B... Yoke lower lid part, 9C...
Yoke upper cover, 10...terminal pin.

Claims (1)

[Scope of Claims] 1. First and second magnetic bearings, a cylindrical permanent magnet magnetized in the axial direction and provided on the outer periphery of the first bearing, and the first and second bearings. a non-magnetic load shaft that is rotatably supported by a non-magnetic load shaft, and a length that is integrally provided with the load shaft, is rotatable between the bearings, and is shorter than the distance between the first and second bearings. a cylindrical iron core made of a magnetic material; a bobbin provided on the outer periphery of the iron core, the first bearing, the permanent magnet and the second bearing; A magnetic disc is provided, a solenoid coil consisting of a coil wound on both sides of the disc, and a yoke that covers the outer periphery of the first bearing, the permanent magnet, the second bearing, and the solenoid coil. The contact pressure between the iron core and the bearing is adjusted by the current flowing through the coil, thereby adjusting the friction between the iron core and the first bearing, thereby adjusting the torque required to rotate the load shaft. At the same time, a magnetic flux of a certain amount or more in the opposite direction to the magnetic flux generated by the permanent magnet is generated to cause the iron core to
Rotary load variable solenoid with clutch configured to move in the direction of the bearing. 2. The rotary load variable solenoid with a clutch according to claim 1, wherein the pair of magnetic bearings are fitted into the inner periphery of the bobbin. 3. The rotary load variable solenoid with a clutch according to claim 2, wherein the yoke is cylindrical and forms a magnetic circuit between one pole of the permanent magnet and the second bearing.