JPS61236399A - Rotor brake device - Google Patents

Abstract

PURPOSE:To enable to apply the prescribed brake torque irrespective of the rotating speed of a rotor by providing a supporting plate for supporting a permanent magnet disposed near the rotor having a conductor in engagement with the rotational shaft of the rotor. CONSTITUTION:A ring-shaped conductive electromagnetic soft iron ring 5' is engaged integrally with a collar 5a of a flywheel 5. A disc-shaped electromagnetic soft iron plate 8 is provided at an ultrafine gap from the wheel 5, permanent magnets 11 are provided at an equal interval on the circumference of the plate 8, and an electromagnetic soft iron plate 7 is provided on the magnets 11. When the flywheel 5 is rotated, a brake torque is generated between the ring 5' and the plate 8. When the torque becomes larger than the torque value for stopping the plate 8 on the basis of a load 13, the plate 8 is rotated in the same direction as the wheel 5 to reduce the brake torque.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating body motion device that applies a constant braking torque to a rotating body having rotational inertia, and particularly to one that can be applied to a stationary motion device.

[Conventional technology]

BACKGROUND ART Conventionally, as a first means for applying braking to a rotating body, that is, applying a braking torque, there are methods that use a mechanical friction brake such as a disc type or a belt type.

A second method is to set up a generator and adjust the output current to generate a predetermined braking torque.

As a third method, there is a method in which the rotating body is made of a conductor, a magnetic circuit is formed by a coil sandwiching the conductor, and braking torque is applied by the eddy current generated when the magnetic flux crosses the rotating conductor.

[Problem that the invention seeks to solve]

Among the above-mentioned conventional rotary body motion devices.

The first method has the disadvantage that it is poor in durability because it causes wear of the brake part, and also generates sliding noise as noise.

The second method can generate accurate braking torque without contact and without generating noise, but since the generated current is passed through a resistor to generate braking torque, it is difficult to apply it to a stationary exercise device. This requires a 300 to 400 W generator, a large variable resistor, a cooler, etc., and is disadvantageous in terms of cost.

Furthermore, like the second means, the third means is also non-contact.

Although it is possible to generate braking torque with high accuracy without generating noise, it requires a power source to supply current to the coil, which has the drawback of being disadvantageous in terms of cost.

In order to apply a constant braking torque regardless of the rotational speed of the rotating body, the second method requires a constant current load circuit, and the third method requires a circuit that controls the coil current using a strain gauge, etc. The present invention is intended to solve the above-mentioned problem, and its contents will be explained below with reference to FIGS. 1 to 3.

The flywheel 5 is a chain 2. It is connected to the pedal rotating section 1 and the transmission 3 via a timing belt 4. Further, the flywheel 5 is connected to a shaft 18 via a bearing 16.
rotate around. A ring-shaped conductive electromagnetic soft iron shaft 5' whose thickness gradually increases or decreases in the direction of the rotational axis of the flywheel 5 is fitted and integrated into the flange 5a of the flywheel 5.

A disc-shaped electromagnetic soft iron plate 8 with a small gap between the electromagnetic soft iron shaft 5
A plurality of permanent magnets 11 made of ring-shaped ferrite are provided at equal intervals around the circumference of the electromagnetic soft iron plate 8.
An electromagnetic soft iron plate 7 is provided on the permanent magnet 11, and the permanent magnet 11 and the electromagnetic soft iron plate 7.8 are integrated with non-magnetic screws 20. The electromagnetic soft iron plate 8 is screwed (screwed) onto the shaft 1o at a threaded portion 10a, and the electromagnetic soft iron plate 8 is rotatable and movable in the direction of the rotation axis of the flywheel 5. A wire rope 15 is once fixed to the rope winding portion 8a of the electromagnetic soft iron plate 8, and a load 13 for applying a constant braking torque is provided at the other end.

[For production]

The magnetic flux generated by the magnet 11 exits the electromagnetic soft iron plate 7, passes through the air gap, passes through the electromagnetic soft iron shaft 5', returns to the electromagnetic soft iron plate 8 through the air gap again. At this time, leakage of magnetic flux can be prevented by the presence of the electromagnetic soft iron plates 7 and 8.

When the flywheel 5 is rotated by the belt, an eddy current is generated in the electromagnetic soft iron shaft 5', and the relative speed between the electromagnetic soft iron shaft 5' and the electromagnetic soft iron plate 8 is changed between the electromagnetic soft iron shaft 5' and the electromagnetic soft iron plate 8. A braking torque is created which is to be reduced.

The strength of this braking torque is determined by the square of the magnetic flux density perpendicular to the rotation direction of the electromagnetic soft iron shaft 5' and the electromagnetic soft iron shaft 5' and the electromagnetic soft iron plate 8.
It is proportional to the square of the relative rotational speed. When this braking torque becomes larger than a torque value that can stop the electromagnetic soft iron plate 8 based on the load 13, the electromagnetic soft iron plate 8 is rotated in the same direction as the flywheel 5. Then, the electromagnetic soft iron plate 8 is moved in a direction away from the flywheel 5 by a screw cut in the shaft 10.

This movement increases the amount of air gap between the electromagnetic soft iron plate 8 and the electromagnetic soft iron shaft 5', which increases magnetic resistance, reduces eddy current, and reduces braking torque.

Then, at a position where this braking torque becomes equal to a constant reverse rotation torque based on the load 13, the electromagnetic soft iron plate 8 stops rotating and stands still.

In this way, regardless of the rotational speed of the flywheel 5, the braking torque of the flywheel is equal to the reverse rotation torque based on the load 13, so that the braking torque is always constant. Note that the absolute value of the constant braking torque can be changed by appropriately selecting the load.

〔Example〕

The present invention will be explained in detail below.

FIG. 2 is a schematic diagram of a stationary motor vehicle motion device to which the present invention is applied. 1 is a pedal rotation part, 2 is a chain, 3 is a transmission consisting of a speed increasing pulley, 4 is a timing belt, 5
is a flywheel, and 6 is a gear receiving the driving force of the timing belt 4.

Although the transmission 3 is shown in the figure, the flywheel 5 may be directly driven by a chain or belt from the pedal rotating section 1.

FIG. 3 is a side view of the flywheel 5. The flywheel 5 is made of a cast iron disc, and the flange 5a has an electromagnetic soft iron shaft 5.
' is inserted. The permanent magnets 11, which are sandwiched between the electromagnetic soft iron plates 7 and 8 and fixed with non-magnetic screws 2o, are ring-shaped and made of ferrite, and a plurality of them are arranged around the electromagnetic soft iron plate 8 (for example, 8 magnets are arranged at equal intervals in the circumferential direction). provided.

Figures 1 (a) and (b) show the A-A cross section in Figure 3, 5'
is an electromagnetic soft iron shaft fitted inside the flange 5a of the flywheel 5, which improves magnetic properties when the flywheel 5 is made of cast iron. The flywheel 5, the electromagnetic soft iron shaft 5', and the gear 6 are integrated and rotated around a fixed shaft 10 via a bearing 16. Note that the position of the flywheel 5 in the rotation axis direction is fixed by the bearing 16.

8 is an electromagnetic soft iron plate that is screwed into the threaded part 10a of the shirt 10 (
When the electromagnetic soft iron plate 8 is rotated, it moves in the axial direction of the shirt 10.

Note that the position where the electromagnetic soft iron plate 8 contacts the thrust bearing 18 is the initial position in the axial direction. The direction of movement of the electromagnetic soft iron plate 8 is such that when the electromagnetic soft iron plate 8 rotates in the same direction as the rotating direction of the flywheel 5, it moves away from the flywheel 5.

A plurality of permanent magnets 11 are fixed to the circumference of the electromagnetic soft iron plate 8, and the electromagnetic soft iron plates 7, 8 and the permanent magnets 11 are connected to the non-magnetic screws 2.
It is unified at 0.

The magnetic flux generated by the permanent magnet 11 exits from the tip of the electromagnetic soft iron plate 7, passes through the gap, passes through the electromagnetic soft iron shaft 5', and forms a magnetic path that reaches the tip of the electromagnetic soft iron plate 8 via the gap.

As shown in the figure, the electromagnetic soft iron shaft 5' is formed in a tapered shape whose thickness gradually increases or decreases in the axial direction of the shaft 10, and the tip of the electromagnetic soft iron plate 7.8 and the electromagnetic soft iron shaft 5' The amount of air gap changes as the electromagnetic soft iron plate 8 rotates.

Regarding the rope winding of the eight electromagnetic soft iron plates 8, a wire rope 12 with one end fixed by a stopper 17 is wound around the part 8a for one or more turns, and a load 13 is provided at the other end of the wire rope 12. The electromagnetic soft iron plate 8 is rotated by the load 13 so as to approach the flywheel 5, but its rotation is regulated by the thrust bearing 18 in the initial state. When the electromagnetic soft iron plate 8 rotates in the same direction as the flywheel 5 as described later, the wire rope 12 is wound in parallel following the rope winding part 8a, and the load 13 is pulled up and fixed on the electromagnetic soft iron plate 8. Add reverse rotation torque.

Now, when the flywheel 5 is rotated by the belt, an eddy current is generated in the electromagnetic soft iron shaft 5' and the relative speed between the electromagnetic soft iron shaft 5' and the electromagnetic soft iron plate 8 is generated between the electromagnetic soft iron shaft 5' and the electromagnetic soft iron plate 8. A braking torque is created which is to be reduced.

The strength of this braking torque is determined by the square of the magnetic flux density perpendicular to the rotation direction of the electromagnetic soft iron shaft 5' and the electromagnetic soft iron shaft 5' and the electromagnetic soft iron plate 8.
It is proportional to the square of the relative rotational speed.

Therefore, when the rotational speed of the flywheel is increased, a large braking torque is generated.

The above braking torque tries to rotate the electromagnetic soft iron plate 8 in the same direction as the flywheel 5, so if the electromagnetic soft iron plate 8
When a braking torque larger than the reverse rotation torque based on the load 13 that stops the rotation of the electromagnetic soft iron plate 8 is caused to rotate in the same direction as the flywheel 5.

When the electromagnetic soft iron plate 8 rotates in the same direction as the flywheel 5, the electromagnetic soft iron plate 8 is moved away from the flywheel 5 by the threaded portion 10a of the shaft 10.

This movement increases the amount of air gap between the tip of the electromagnetic soft iron plate 7.8 and the electromagnetic soft iron shaft 5', and as the magnetic flux density decreases, the generation of eddy current becomes smaller, so that the braking torque decreases.

Then, at a position where this braking torque becomes equal to the reverse rotation torque due to the load 13, the electromagnetic soft iron plate 8 stops rotating and stands still.

In this state, a braking torque equal to the reverse rotation torque is applied to the flywheel 5.

When the rotation speed of the flywheel 5 is further increased, the eddy current increases and the braking torque exceeds the reverse rotation torque, and the electromagnetic soft iron plate 8 rotates further away from the flywheel 5 and reaches a position balanced with the reverse rotation torque. Stand still.

Note that when the rotational speed of the flywheel is lowered, the reverse rotation torque based on the load 13 exceeds the braking torque, and the electromagnetic soft iron plate 8 rotates and approaches the flywheel 5, thereby increasing the braking torque and increasing the braking torque based on the load 13. The electromagnetic soft iron plate 8 comes to rest at a position balanced with the reverse rotation torque.

Therefore, when the electromagnetic soft iron plate 8 is stationary, the braking torque of the flywheel 5 is equal to the reverse rotational torque due to the load 13, and a constant braking torque is provided regardless of the rotational speed of the flywheel 5.

By appropriately selecting the weight of the load 13, any constant braking torque can be applied.

[Modified example]

In the above embodiments, a spring or the like may be used instead of the wire rope 12.

In addition, although the thickness of the electromagnetic soft iron ring 5' in the direction of the rotation axis is made non-uniform, it may be constant; in this case, the thickness of the electromagnetic soft iron plate 7
By making the outer end surface of the electromagnetic soft iron ring 5' protrude from the outer end surface of the electromagnetic soft iron ring 5', the amount of air gap is increased and the braking torque is reduced.

Further, in the above embodiment, the permanent magnet 11 is made of ring-shaped ferrite, but a square-shaped one may be used instead of the ring-shaped one, or alnico may be used instead of ferrite.

However, ring-shaped ferrite magnets are produced in large quantities for use in speakers and are inexpensive.

In the above embodiments, an automobile was used as an example of the stationary exercise device, but it is clear that a board or the like may also be used.

In addition to exercise equipment, the present invention can also be applied to a characteristic testing machine for prime movers such as motors, and the current-torque characteristics can be measured by driving the flywheel with the motor to be measured.

It is also possible to attach a tachometer to the flywheel and calculate the amount of work, which is the product of rotation speed and torque.

C Effects of the Invention As described above, according to the present invention, a constant braking torque can be applied regardless of the rotation speed of the rotating body, and braking can be applied without contacting the rotating body, causing no wear and noise. Longer life is achieved.

In addition, since no external power is required, it is suitable for use as a stationary exercise device that is portable and used outdoors.

[Brief explanation of drawings]

Figures 1 (a) and (b) are diagrams of one embodiment of the present invention, Figure 2 is a schematic diagram of a stationary vehicle, Figure 3 is a side view of the flywheel section, 1 is a pedal rotation section, 3 is the transmission, 5 is the flywheel,
5' is an electromagnetic soft iron ring, 7 and 8 are electromagnetic soft iron plates, 8a is a rope winding part, 10 is a shaft, 10a is a threaded part, 11 is a permanent magnet, and 12 is a wire rope. 13 is a load, and 20 is a non-magnetic screw.

Claims (1)

[Scope of Claims] A rotating body that is rotated by a predetermined power and includes at least a conductor portion, and a permanent magnet arranged near the rotating body,
In a rotating body moving device that applies braking torque to a rotating body by generating an eddy current, a support plate that supports the permanent magnet and is rotatable is provided so as to be threadedly engaged with the rotating shaft of the rotating body, and a constant force is attached to the support plate. A rotating body motion device characterized by being equipped with a load.