JPS6135155A - Brake device - Google Patents

Abstract

PURPOSE:To obtain a brake device having a low cost and high brake efficiency by securing yokes to both surfaces of a permanent magnet, opposing the both end poles through a gap, and disposing a cup-shaped conductive part cooperated with a drive wheel in the gap. CONSTITUTION:A yoke 4 having a pole 4a is mounted on the periphery at one end of a permanent magnet 3 magnetized in the thicknesswise direction, a yoke 5 having a pole 5a is mounted on the periphery at the other end, and the both poles 4a, 5a are opposed through a gap. On the other hand, a rotary member (accelerating pinion) 6 is cooperated with the plate 7, and an eddy cup 9 made of a conductive member is coupled with the member 6. The edge 8b of the cup 8 is disposed in a gap between the yokes 4 and 5. Thus, the eddy current brake force proportional to the rotating speed can be efficiently obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a braking device that makes full use of eddy currents.

[Conventional technology]

A conventional braking device of this type includes magnets N arranged oppositely in the thickness direction on a part of the outer periphery of the magnetically conductive rotating disk.

Some have an S pole. Another example is to make a plurality of recesses in the axial direction on the outer circumference of a donut-shaped magnet, magnetize the S pole in the circumferential direction, and fix the eddy current sheet metal to the inner surface of a cup-shaped yoke. There are those that rotate the entire rotation or rotate the yoke and the swirl plate.

[Problem that the invention seeks to solve]

Among these conventional techniques, the former has poor eddy current generation efficiency because eddy currents are generated only in a part of the disk;
Since there are many 1fC leakage magnetic pots, the magnetic efficiency decreases accordingly. In addition, the latter is expensive because the magnet has a complicated shape and is difficult to process, and both the inertia is large and difficult to brake, whether the magnet is rotated fully or the yoke and swirl plate are rotated. .

The object of this invention is to provide a braking device k with excellent magnetic efficiency, low cost, and good braking efficiency.

[Means for Solving the Problems J] This invention provides a fully solid-layered yoke in which a plurality of magnetic poles are all protruded from one surface of a donut-shaped magnet magnetized in the thickness direction. A yoke having a plurality of magnetic pole parts facing the above-mentioned magnetic pole parts with gaps formed on its surface is solidly layered, and a cup-shaped four-electroelectric member whose edge can pass through the gap between the opposing magnetic pole parts is driven. For this reason, in this invention, the rotation of the driving wheel that drives the driven body is accelerated and transmitted to the rotating member. The conductive member rotates together with the rotating member. Pass the magnetic pole part of one yoke and the magnetic pole part of the other yoke from the N%1A of the magnet to the S of the magnet.
Since the magnetic paths leading to the poles are formed at multiple locations on one side of the magnet, the rotation of the magnet creates a dense and dense magnetic flux density. The edges of the conductive member rotate across this magnetic flux within the gap between the pole pieces. For this reason, an eddy current is generated in the conductive member, and an eddy current braking force proportional to the rotational speed of the conductive member efficiently acts on the conductive member.

〔Example〕

As shown in Figure 1.2, the central axis 2 stands up on the plate 1 for installation. The donut-shaped ferrite permanent magnet 3 is magnetized in its thickness direction. One surface (upper surface) K of the magnet 6 has one yoke 4 fixed thereto as shown in the second figure, and magnetic pole portions 4a, 4b, 4c, and 4d protrude from four locations on the outer periphery of the yoke. be. The other yoke 5 is solidly layered on the other surface (lower surface) of the magnet 6, and 4 yoke 5 extending from four points on the outer periphery
The arm of the book is bent, and the magnetic pole parts 5a, 5b, 5 at the tip thereof are bent.
+c, 5d are between the magnetic pole parts 4 a to 4 d and the distance N'
They are facing each other. The thus formed magnet 5 and yoke 4.5 are fixed to the central shaft 2.

As shown in Figure 1.6, the upper end 2aKU of the central shaft 2 and a speed increasing pinion 6, which is a rotating member, are rotatably supported. The speed increasing pinion 6 rotates in conjunction with the drive wheel 7 at increased speed. A vortex cup 8 as a conductive member is solidly layered on the speed increasing pinion 6. The vortex cup is made of copper, and the disc part is provided with through holes 8a for weight reduction. The edge 8b of the cup has opposing magnetic pole parts 4a and 5a, 4b and 5b, 4c and 5c,
It is possible to pass through the gap between 4d and 5d. The drive wheel 7 is rotatably supported on a central shaft 10 hanging from a plate 9. The rotation of the drive wheel 7 drives a driven body (not shown).

The eddy current braking force F(t) due to this braking device is l and B
g: Magnetic flux density of the gap 8g: Cross-sectional area of the gap v(t): Speed of the conductor in the gap Kh; Thickness of the vortex cup KB: Correction coefficient due to magnetic pole shape ζ: Specific resistance of the cup η: Efficiency .

In order to evaluate the braking force exerted on the driven body, the head of the printer was moved as the driven body by the driving wheel 7, and the head was returned to its original position by a spring. and B g −= D, 52 wb2 layer.

Ag=48XI-bi, h=α8X111i'□.

KB=0.4255. ζ= 1.72 x 10-'
I installed it in Ω□ and investigated its braking force. The efficiency η is 46% when the speed increasing ratio between the driving wheel 7 and the speed increasing pinion 6 is 2.05.

It was 86% for the speed increase ratio of 3.14.

Prior to the test, when the braking device of the present invention was attached to the drive wheel 7 and the printer head was returned to its original position by a spring, the final return speed was 0.72 m/sea.

Therefore, as a result of testing the braking device of the present invention connected to the driving vehicle 7, it was found that with a speed increase ratio of 2.05, the final return speed was 0.
．． If the speed is 55 m/eθC and the speed increasing ratio is 6.14, the final return speed is 0.57? M/BθC.

[Effects of the Invention] Since the magnet of the present invention has a simple shape, it is easy to process and can be made at low cost.Since there is little magnetic flux leakage from the magnetic circuit, magnetic efficiency is good, and a large magnetic flux density can be obtained with a small magnet. 1fC
Since multiple magnetic flux density concentration points are created for one magnet,
Braking efficiency is good because braking force is obtained all around the conductor that passes through it.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the main parts in the embodiment of the present invention, Fig.
The figure is a sectional view taken along the line II-II in Figure 1, and Figure 3 is a cross-sectional view taken along the line II-II in Figure 1.
FIG. 3...Permanent magnet, 4,5...Yoke, 4a~4
d, 5a to 5d... magnetic pole part, 6... speed increasing pinion,
7... Drive wheel, 8... Vortex cup, 8b@φ・
Edge. From then on

Claims (1)

[Scope of Claims] A permanent magnet magnetized in the thickness direction, one yoke fixed to one surface of the magnet and forming a plurality of magnetic poles, and fixed to the other surface of the magnet. the other yoke, which has a plurality of magnetic pole parts facing the magnetic pole parts of the one yoke with a gap therebetween; and a rotating member which is rotatably supported in conjunction with a drive wheel. and a cup-shaped conductive member that is fixed to the rotating member and whose edge can pass through the gap.