JPH069765Y2 - Rotating saw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotary saw provided with means for preventing the generation of noise called metal noise that significantly deteriorates the working environment when the rotary saw idles.

(Prior Art) Generally, when a rotary saw is rotated at a high speed, the blade edge of the saw cuts air, and then an air vortex called a Karman vortex is formed. When the frequency of this vortex resonates with the natural frequency of the saw body, a very loud high frequency metallic sound is generated.
This metallic noise makes the working environment significantly worse. Therefore, various methods have been announced so far in order to prevent such high-frequency metallic noise. For example, as shown in FIG. 2A, the split groove 2 is provided at several places from the tooth bottom 1 of the rotary saw toward the center, and the stress concentration due to the split groove 2 shown in FIG. 2A is increased as shown in FIG. 2B. A padding 4 made of aluminum, copper, or the like is provided in a round hole 3 provided at an inner end portion of the split groove 2 to prevent it.
Are embedded, and so on.

In addition, a rotary saw with a crack-like split streak around the saw body (Japanese Patent Application No. 48).
-127746), the length from the root 1 to the round hole 6 at the tip of the splitting muscle 5 is shown in FIGS. 2A and 2B, as shown in FIGS. 2C and 2D. It is not suitable for heavy-duty cutting because it is more likely to cause misalignment than a saw that is used.

Furthermore, it is known that a rotary saw provided with a perforation 7 called a window shown in FIG. 2E has an effect of preventing metallic noise. It has been found that embedding an object, which has substantially the same shape and size as the hole and is made of a material (for example, plastic) different from the material of the rotary saw, has a great effect on the prevention of metallic noise. .

The purpose of this is to change the natural frequency of the saw to prevent resonance with the Karman vortex and to absorb the vibration of the saw by the padding.

(Problems to be solved by the invention) The conventional noise-preventing circular saws have punched out a part of the circular saw body and provided circular holes 3 and 6 perforated portions 7 and made of aluminum, copper, plastic or the like. Work such as embedding the filling was necessary. This is to prevent the resonance with the Karman vortex by absorbing the vibration of the saw or changing the natural frequency of the saw itself depending on the characteristics of the padding itself. Since such a filling is generally different from the material of the saw itself, it is difficult to fix it.

According to the present invention, a padding made of the same material as the saw itself is arranged so as to be substantially in sliding contact with the perforated portion of the saw, and a part of the padding is fixed to the saw body so that the natural frequency of the saw is It is converted into a frictional force with the padding, thereby preventing noise caused by rotation of the saw.

(Means for Solving the Problems) In order to solve the above problems, according to the present invention, a saw having a shape that makes sliding contact along the inner length of the perforated portion provided in the saw body over as long a distance as possible is provided. Fill with a pad of the same material. A part of the padding is fixed to the saw body to prevent the padding from coming off.

(Operation) The vibration energy generated by the rotation of the saw is replaced with the thermal energy by the sliding contact friction between the saw and the padding to prevent noise generation.

(Embodiment) FIG. 1 shows an embodiment embodying the present invention. In this embodiment, a circular saw 10 having a mounting hole 12 in the central portion and a cutting blade 14 in the peripheral portion has a saw body portion 16 having a plurality of cutout holes 15 similar to those shown in FIG. 2E. The first hole in the cutout
A padding 18 as shown in Figure 1B is embedded.

The padding 18 has a shape substantially the same as the shape of the cutout hole 15, and it is possible to use the one punched from the saw body portion 16 or the one punched from another sheet member, and generally, The padding 18 is constructed of the same or thinner material as the body portion 16 of the saw.

In FIG. 1C, a split streak 20 is formed at the center of the padding 18a, and holes 21 for preventing stress concentration are provided at both ends thereof.
In this case, friction is simultaneously generated between the saw body and the padding and between the split lines 20, and the soundproofing effect is further excellent.

Figure 1D shows a padding 18b with notches on both sides.
In this case, however, the convex portion is brought into frictional contact with the saw body, and at the same time, ventilation is achieved through the cutout portion, and a heat dissipation effect by this is expected.

FIG. 1E is a further development of the specific example of FIG. 1D, and the padding 18c is made of a spring material or the like.

FIG. 1F is another specific example, and shows a padding 18d made of a spring material as in FIG. 1E.

Each of these plugs contacts the side wall surface of the cutout hole, and acts to convert the vibration of the saw into a frictional force as described above.

The paddings 18, 18a, 18b, 18c, 18d are fixed to the saw body at at least one position of the padding material by welding, adhesive, caulking, fitting or the like so as not to come off from the saw body 10 during rotation of the saw.

FIGS. 3 and 4 are graphs showing the results of experiments comparing the noise level of the saw of the present invention with a known saw of the same type. All of these experiments were conducted in a small room with sound absorbing material
The sound pressure level at each rotation speed was measured by a normal sound level meter at a position separated by m. All saws are 305 mm in diameter, 2.0 mm thick and have 100 teeth.

In FIG. 3, A is a known saw having eight perforations, and B is
A saw in which steel having the same shape and size as the hole shown in FIG. 1B and having the same material as that of the saw body is embedded in the hole, and a central point of the steel is welded and fixed. As a result, it can be seen that, as the number of revolutions increases, the saw according to the invention clearly has a lower noise level than known saws.

In FIG. 4, D is a known saw that has not been subjected to any countermeasure, and resonance is exhibited at all rotation speeds. E is a known saw in which aluminum is embedded in a circular hole at four places and round holes at the tip thereof as shown in FIG. 2B, and F is a saw in which steel of the form shown in FIG. 1E is embedded in eight holes. . The saw F of the present invention clearly shows that resonance is prevented and sound pressure level is lowered at high speed rotation.

(Effect of the Invention) From these graphs, it was proved that the present invention lowered the sound pressure level and did not generate metallic noise during idling, and that the present invention was extremely effective in practical use.

[Brief description of drawings]

FIG. 1A is a plan view of a circular saw showing an example of the present invention, and FIG. 1B is a plan view.
Perspective view of padding used in FIG. 1A, FIG. 1C, FIG. 1D, 1E
FIG. 1F is a view similar to FIG. 1B showing another specific example, and FIGS. 1G and 1H are sectional views taken along lines GG and HH of FIGS. 1B and 1C, respectively, and FIGS. FIG. 2E is a plan view showing a known circular saw, and FIG.
FIG. 4 and FIG. 4 are views showing experimental data showing noise levels of the circular saw of the present invention and a known circular saw. DESCRIPTION OF SYMBOLS 1 ... Tooth root, 2 ... Split groove, 3 ... Round hole, 4 ... Filling, 5 ... Split line, 6 ... Round hole, 7 ... Drilled portion, 10 ... Circular saw, 14 ... Cutting blade, 15 ... Cutout hole, 16 … Saw body, 18… Filling, 20… Split line, 21… Hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyoshi Akiguchi 7-633 Kamijima, Hamamatsu City, Shizuoka Prefecture Orion Tool Manufacturing Co., Ltd. (56) References JP-A-48-24396 (JP, A) Actual Kai 52-95993 (JP, U) Actual public 47-6312 (JP, Y2) Actual public 33-3998 (JP, Y2)

Claims (1)

[Scope of utility model registration request] 1. A plurality of perforations are provided in the saw body to prevent resonance between the frequency of a Karman vortex generated behind the saw blade during rotation of the saw and the natural frequency during rotation of the saw body. The same metal filling as the saw body is slidably attached to almost all of the perforations, and a part of the filling is fixed to the saw body, whereby the energy of natural vibration during rotation of the saw body is transferred between the saw and the filling. A rotary saw having a structure capable of converting into friction energy.