JPH0142675Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a device for preventing squeals produced during braking of a band brake used for a bicycle or the like.

(Prior Art) Band brakes used for bicycles have traditionally had the problem of generating unpleasant squeals during braking. In order to prevent this noise, it is necessary to change the material and shape of the lining, add dampers to the parts to attenuate vibrations, and change the natural frequency of each part so that the parts do not resonate. There are ways to do this. However, since it is important to reduce the weight and cost of brake devices for bicycles and other devices, it is currently not possible to expect great effects from preventive measures that meet these requirements.

The mechanism behind band brake squeal is that frictional vibration is generated by frictional sliding between the lining and drum, and this vibration is transmitted to the brake device band, bell crank, case, car body, etc. As a result, any one of these is the source of the sound. An unpleasant squeal occurs. In order to prevent this squeal, measures must be taken using the methods described above, but in the case of bicycle band brakes, each part is made of thin plates that easily transmit vibrations, and there are restrictions in terms of weight and cost. Therefore, countermeasures become difficult.

A conventional band brake will be explained with reference to FIGS. 9 to 12. 1 is a brake drum, 2 is a soft lining, 3 is a steel band, and the lining 2 is fixed to the band 3 with rivets 4. An end 3b of the band 3 is attached to the vehicle body by a pin 5, and the other end 3a of the band 3 is attached to a bell crank 6. Then move the bell crank 6 to arrow A in Figure 9.
By pulling in this direction, the lining 2 comes into pressure contact with the drum 1 and generates a braking force.

When this band brake generates braking force,
As shown in FIG. 11, frictional vibrations occur on the sliding surface B. At the same time, vibrations are generated on the back surface C of the lining 2 in the same way as the braking force, and frictional vibrations occur on both surfaces. Generally, since the drum 1 and the band 3 are made of substantially the same material, the coefficient of friction with the lining 2 is also substantially the same. Therefore, even if the lining 2 and the band 3 are fixed with the rivets 4, the frictional vibrations on both sides of the lining 2 are almost the same, and the entire lining 2 vibrates greatly due to the frictional vibrations. On the other hand, since the band 3 fixed to the lining 2 is also a thin plate with a small mass and a simple shape, the lining 2 and the band 3 are affected by the vibration of the lining 2, and as shown in Fig. 11, the lining 2 and the band 3 are The vibration starts and becomes a large vibration as shown in Fig. 12, which is transmitted to other parts.

(Purpose and structure of the invention) This invention was made in order to solve the problem of band brake squeal mentioned above.
A thin plate with a plurality of distributed openings is inserted into the middle part E, which is a part of the circumference of the Reinig, and when the band, the thin plate, and the lining are fixed with rivets, an elastic material is attached to the outside of the band. By inserting and fixing the washer, the purpose is to attenuate vibrations generated on the sliding surface of the drum and prevent unpleasant squeals.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 8. In the figure, the same reference numerals as the above-mentioned reference numerals indicate equivalent parts. Also in the device of the present invention, the relationship among the drum 1, lining 2, band 3, and bell crank 6 is as follows.
It is the same as a conventional band brake. However, as shown in FIG. 2, the lining 2 and the band 3 have a planar shape with several openings 7a distributed between them, and the lining 2 has a thin plate 7 made of a material different from that of the band 3.
Insert it into the middle part E which is a part of the circumference of. The fixing of the band 3 and the lining 2 in the part where the thin plate 7 is not inserted using the rivets 4 is the same as the conventional method, but the method of fixing the lining 2 in the part where the thin plate 7 is included is that the band 3 and the lining 2 are in contact with each other. An elastic washer 8 is applied to the outside of the band 3 on the opposite side, and the lining 2, thin plate 7, and band 3 are fixed with rivets 9. Note that 10 is a metal washer applied to the outside of washer 8.

(Operations and Effects) The frictional vibrations generated during braking of the band brake according to the present invention are the same as those of the conventional band brake at sections D and F in FIG. 1, but are different at section E. The state of vibration shown in FIGS. 4 and 5 is G-G in FIG. 2 of the inserted thin plate 7.
This is in cross section. That is, lining 2
When pressed against the drum 1 to generate braking force, frictional vibrations occur on the sliding surface H, and the back surface I of the lining 2
Vibration also occurs. In the device of the present invention, since the band 3 and the thin plate 7 are made of different materials, the coefficient of friction with the lining 2 is also different, and the frictional vibrations generated on both sides of the lining 2 are naturally different. Therefore, the vibrations on both sides interfere with each other, and the vibration of the lining itself becomes smaller. Frictional vibration also occurs on the sliding surface J between the thin plate 7 and the band 3, but in this case, the vibration is different from that in the case of the lining 2 because it is friction between metals. In this way, G in Figure 2
- The way in which vibrations are transmitted on the G plane is that frictional vibrations are attenuated in the lining 2 and transmitted to the thin plate 7, and further attenuated between the thin plate 7 and the band 3 and transmitted to the band 3.
Due to these effects, the vibration having the amplitude shown in FIG. 12 described above is attenuated as shown in FIG. 5. Next, the manner in which vibrations are transmitted on the KK plane in FIG. 2 is as shown in FIGS. 6 and 7. In this case, since the thin plate 7 has the cutout opening 7a, the frictional vibration is more easily damped. That is, the portion of the thin plate 7 without the notch opening is as described above, but in the portion with the notch, the lining 2 is pressed against the drum 1, so that the lining 2 becomes a thin plate as shown in FIG. Enter into the notch at 7. Therefore, the density of the lining 2 changes, and the vibration damping rate also changes. At the same time, since the band 3 and the thin plate 7 on the back surface of the lining 2 are made of different materials, their frictional vibrations also differ. In addition, when fixing the lining 2, band 3, and thin plate 7 with the rivets 9, an elastic washer 8 is inserted.
Each member vibrates freely to some extent. In this way, various vibrations are generated, and when they interfere with each other and are finally transmitted to the band 3, they become damped vibrations as shown in FIG. 7.

As described above, the vibration transmitted to the band 3 changes by inserting the thin plate 7 having a non-uniform shape. These are vibrations in one section of the lining 2 and band 1, but if we consider them as vibrations across the entire width of the lining 2 and band 3, the vibrations in Figures 5 and 7 interfere with each other, resulting in vibrations in the 8 It is further attenuated as shown in the figure. In addition, the vibration of the entire circumference of the band 3 is caused by different vibrations within one vibration system, such as the vibration of the part D, the vibration of the part E, and the vibration of the part F in Fig. 1. interfere with each other, further damping the vibrations.

In this way, according to the present invention, it has become possible to solve the conventional problem of band brake squeal easily, easily, and at low cost. Measures to prevent band brakes from squealing have long been available, such as attaching a spring to the back of the band or using double steel bands to suppress vibration. However, these methods do not take advantage of the characteristics of the lining, which is a damping material, and since the lining and band are integrated, they become a single vibration system that tends to vibrate, and furthermore, they do not force frictional vibration. The effect was relatively small due to reasons such as trying to attenuate it. In contrast, the anti-squeal device of the present invention takes advantage of the characteristics of the lining as a damping material, and since the vibration system is divided into several parts, each vibration interferes with each other and is attenuated, making it effective. It has the excellent effect of preventing brake squeal.

[Brief explanation of the drawing]

Fig. 1 is a front view of a band brake equipped with the device of the present invention, Fig. 2 is a plan view of a thin plate, Fig. 3 is a partially enlarged cross-sectional view of the band brake of the present invention, and Fig. 4 is a line G--G in Fig. 2. An explanatory diagram of the frictional vibration state on the G plane,
Figure 5 is the vibration waveform diagram, Figure 6 is the K of Figure 2.
- An explanatory diagram of the frictional vibration state on the K plane, Fig. 7 is its vibration waveform diagram, Fig. 8 is a vibration waveform diagram of the entire thin plate insertion part, Fig. 9 is a front view of the conventional band brake, and Fig. 10 11 is an explanatory diagram of the frictional vibration state of the conventional band brake, and FIG. 12 is its vibration waveform diagram. 1... Drum, 2... Lining, 3... Band, 4... Rivet, 5... Pin, 6... Bell crank, 7... Thin plate, 8... Elastic washer, 9
... Rivets, 10 ... Washers.

Claims (1)

[Scope of utility model registration request] In a band brake that obtains braking force by pressing a soft lining against the flange of the brake drum via a steel band, a band brake with a shape in which multiple openings made of a different material than the band are distributed between the band and the lining. The squeal of a band brake characterized by inserting a thin plate into the middle of the lining circumference and fixing the band, thin plate and lining with rivets, by inserting an elastic washer on the outside of the band. Prevention device.