RU76596U1 - DISK SAW WITH A DIAMETER FROM 400 TO 560 mm FOR LONGITUDINAL CUTTING OF WOOD - Google Patents

Abstract

The utility model relates to the field of sawmilling and woodworking, in particular to circular saws, and can be used in various milling and sawing and sawing devices designed for longitudinal processing of wood. Circular saw with a diameter of 400 to 560 mm, thickness S = (2.8-4.0) mm for longitudinal sawing of coniferous wood, preferably on multisaw machines with an even number of teeth and a widening of the cutting crown on each side from 0.5 to 1.0 mm, the height of the teeth h = 25 ± 5 mm, the angle of sharpness of the teeth β = 40 ± 10 °, and the rake angle γ = 25 ± 10 °, characterized in that the number of teeth Z of the saw is determined by the dependence

,

where D is the outer diameter of the saw. The design of the inventive saw allows almost one and a half times to reduce the effort and expended cutting power. The reduced number of teeth significantly reduces the cost of their manufacture, reduces the possibility of overheating of the saws and increases their resistance between regrinding, and also reduces the cost of regrinding the saws during their operation. The performance of the saws was tested on prototypes at woodworking enterprises of the Kirov region. Preparations are underway for the mass production of such saws.

Description

The utility model relates to the field of sawmilling and woodworking, in particular to circular saws, and can be used in various milling and sawing and sawing devices designed for longitudinal processing of wood.

Known circular saws, (GOST 980-80 "Round circular saws for sawing wood"). They are made of alloy steel and with diameters from 400 to 560 mm have a thickness of 2 to 2.8 mm and the number of teeth from 48 to 120.

The disadvantage of saws is that they have a small resource and require frequent grinding of teeth, which with such a number of teeth is a very time-consuming process, and especially for multi-saw machines.

Known circular saws with carbide inserts. (GOST 9769-79 "Circular saws with carbide inserts for the processing of wood materials"). The thickness of the saws ranges from 2 to 3 mm, and the number of teeth is in the range from 56 to 72. Such saws are more durable in operation and their regrinding is made much less frequently.

From the above analogues it is seen that the known saws have a sufficiently large number of teeth from 48 to 72, which creates some problems in the operation of such saws.

Firstly, with such a number of teeth, several saw teeth are simultaneously involved in the cutting process. As a result of this, the cutting forces are increased, as compared with if, for example, one tooth participated in the cutting process, and the power consumption increases.

Secondly, a large number of teeth requires sufficient time and energy consumption when regrinding such saws.

Partially, the issue of reducing teeth on saws intended for longitudinal sawing of wood, and accordingly reducing labor costs for the manufacture, operation and regrinding of such saws, was solved in the saw design described in the Eurasian patent “Circular saw with a diameter of 400 to 560 mm for sawing coniferous wood

breeds "(Eurasian patent No. 004150. Publication 2004.02.26), which is selected for the prototype of the proposed technical solution.

In the design of this saw, a saw blade of thickness S with a cutting crown formed by an even number of teeth deposited with a wear-resistant Stellite alloy, with a widening of the cutting crown on each side from 0.5 to 1.0 mm, tooth height h = 25 ± 5 mm , the angle of sharpening of the teeth β = 40 ± 10 °, and the rake angle γ = 35 ± 10 °, while the number of teeth Z of the saw and the thickness S of the saw blade are determined by the dependence

Where D is the outer diameter of the saw.

As studies have shown, in the aforementioned saw design, far from all the possibilities of increasing its operational and technical characteristics were used.

The purpose of the utility model is to create a new design of a circular saw with a small number of teeth, which allows to increase its technical and operational capabilities.

To this end, the authors carried out research and development work to determine the optimal design of a circular saw for longitudinal sawing of coniferous and deciduous wood on multi-saw machines with a reduced number of teeth.

In the course of the work, it turned out that for saws with a diameter of 400, 450, 500 and 560 mm, intended for longitudinal cutting and obtaining a two-edged beam of a standard height of 100, 125, 150 and 175 mm and obtaining lumber of a specified width according to GOST 26002-83E, a step is required teeth, respectively, 100, 125, 150 and 175, that is, that the cutting process preferably involved one tooth of the saw, but not more than two teeth.

Based on this condition, it was determined the required number of teeth Z for each diameter of the saw.

Z = L / tooth pitch

Where, the circumference L of the saw corresponding to each diameter D of the saw is expressed as L = (D.

where π = 3.14 is a mathematical constant denoting the ratio of the length L of the circle to the diameter D of the circle.

D is the diameter of the saw circumference in mm.

As a result, we get the number of teeth Z corresponding to each diameter of the saw D and the inventive saw.

⌀ = 400 Z = L / 100 = 12.56, round to Z = 12 ⌀ = 450 Z = L / 125 = 11.3, round to Z = 12 ⌀ = 500 Z = L / 150 = 10.04, round to Z = 10 ⌀ = 560 Z = L / 175 = 10.04, round to Z = 10

The prototype, the number of teeth in relation to the corresponding diameter of the inventive saw is almost 1.4 times higher:

D = 400 mm Z = 22 D = 450 Z = 24 D = 500 Z = 26 D = 560 Z = 28

In addition, the rationale for the rational choice of the required minimum number of teeth of the inventive saw in comparison with the saw according to patent No. 00415, for example, saw ⌀ = 400, is confirmed by the following mathematical formulas:

The feed per tooth for both saws is determined by the formula:

U - feed rate, m / min

Uz - feed per tooth, mm

n is the number of revolutions of the saw per minute

z is the number of teeth

however, for the saw according to patent No. 004150 it is

Uz 1 = 12 × 1000/3000 × 22 = 0.18 mm (Rzmax = 120 μm)

For the inventive saw, it will be

Uz 2 = 12 × 1000/3000 × 12 = 0.33 mm (Rzmax = 220 μm)

The cutting power for both saws is determined by the formula:

N - cutting power, kW

K - specific resistance to cutting, kgf / mm ²

b - cut width, mm

N - cut height

n is the number of revolutions of the saw per minute

z - number of teeth

however, for the saw according to patent No. 004150 it is

N1 = 5.95 × 4.2 × 100 × 0.18 × 22 × 3000/60 × 102 × 1000 = 4.9 kW

For the inventive saw, it will be

N2 = 4.3 × 4.2 × 100 × 0.33 × 1 × 23000/60 × 102 × 1000 = 3.5 kW

(3) The cutting force for both saws is determined by the formula

P = KbHUz × zn / 60V1000 kgf, where

P - cutting force, kgf

N - cutting power, kW

K - specific resistance to cutting, kgf / mm ²

b - cut width, mm

N - cut height, mm

Uz - feed per tooth, mm

n is the number of revolutions of the saw per minute

z - number of teeth

V - cutting speed, m / s,

where V = πDn / 60 × 1000 m / s, where

(- mathematical constant denoting the ratio of the perimeter to the diameter of the circle.

D - saw diameter, mm

n is the number of revolutions of the saw per minute

however, for the saw according to patent No. 004150 it is

P1 = 5.95 × 4.2 × 100 × 0.18 × 22 × 3000/60 × 62.8 × 1000 = 7.88

For the inventive saw, it will be

P2 = 4.3 × 4.2 × 100 × 0.3312 × 3000/60 × 62.8 × 1000 = 5.69

From the foregoing it follows that, with a decrease in the number of saw teeth, the cutting power and cutting force on such saws are reduced and, compared with the prototype, these figures are reduced by about 1.4 times.

At the same time, the surface roughness value of the lumber obtained after sawing (Rzmax) by the inventive saws does not exceed 750 μm and meets the requirements of GOST 26002-83E.

This goal is achieved due to the fact that in a circular saw with a diameter of 400 to 560 mm, a thickness of S = (2.8-4.0) mm for longitudinal sawing of wood, preferably on multisaw machines, including a saw blade with a broadening of the cutting crown on each side from 0.5 to 1.0 mm, tooth height h = 25 ± 5 mm, tooth taper angle β = 40 ± 10 °, and rake angle γ = 25 ± 10 °, according to a utility model, the number of teeth Z of a saw is determined by the relationship

Where D is the outer diameter of the saw.

The essence of the utility model is illustrated by drawings, which depict:

Figure 1 - saw blade;

Figure 2 - saw blade, side view of figure 1;

Figure 3 - remote element I of figure 1.

The circular saw (figure 1) is intended for longitudinal sawing of coniferous and deciduous wood, preferably on multi-saw machines, since it is on these machines that replacing and regrinding saws is a very time-consuming process.

The saw diameter is selected in the range from 400 to 560 mm in accordance with a number of saw diameters provided by GOST 980-80, as the most suitable for longitudinal sawing of wood on multi-saw machines.

The saw has a saw blade 1 with a thickness of S = (2.8-4.0) mm with a cutting crown 2 formed by an even number Z of teeth 3, with a broadening of the cutting crown on each side from 0.5 to 1.0 mm (FIG. 2).

In order to use the well-known and proven saw tooth profile (Fig. 3) with a sharpening angle β, rake angle (and tooth height h, these sizes were chosen in accordance with the recommendations of GOST 980-80 equal to β = 40 ± 10 °, γ = 25 ± 10 (and h = 25 ± 5 mm. In addition, these dimensions allow the use of commercially available equipment for sharpening the teeth of saws. In addition, the saw blade 1 can be equipped with carbide element 4 at the end of the tooth 3.

Experimentally, taking into account the different modes of cutting, heating, deformation of the saws and the above justifications, it was determined and given above the optimal number of teeth Z of the saw blade for each diameter of the saws.

From here we determine a certain coefficient K, which covers the entire range of the claimed saws, and is expressed by the ratio of D to Z

So for the saw min ⌀ = 400 K ₁ will be

And for the saw, min ⌀ = 560 K ₂ will be

Thus, the optimal number of teeth Z of the inventive saw in the General case, covering the entire range of saws can be expressed by the dependence

,

where the coefficient K, taking into account the above K ₁ and K ₂ and rounding off the coefficient K ₁ from 33.33 to 30.0, will be K = (30-56)

Thus, in final form, the optimal number of teeth Z of the inventive saw, in the General case, covering the entire range of saws can be expressed by the dependence D

The design of the inventive saw allows almost one and a half times to reduce the effort and expended cutting power. The reduced number of teeth significantly reduces the cost of their manufacture, reduces the possibility of overheating of the saws and increases their resistance between regrinding, and also reduces the cost of regrinding the saws during their operation.

At the same time, such saws provide the necessary purity of processing the resulting lumber that meets the requirements of GOST 26002-83E. The performance of the saws was tested on prototypes at woodworking enterprises of the Kirov region. Preparations are underway for the mass production of such saws.

List of used literature.

(one). Yakunin N.K. Preparation for operation and operation of circular saws. M. MGUL 2000 p. 341, formula (1.8).

(2). Manzhos F.M. Woodworking machinery. Goslesbumizdat. P. 71, formula (71).

(3). Manzhos F.M. Woodworking machinery. Goslesbumizdat. P. 71, formula (72).

Claims (1)

Circular saw with a diameter of 400 to 560 mm for longitudinal sawing of wood, preferably on multisaw machines with a thickness of S = (2.8-4.0) mm with an even number of teeth and a broadening of the cutting crown on each side from 0.5 to 1.0 mm , the height of the teeth h = 25 ± 5 mm, the angle of sharpening of the teeth β = 40 ± 10 °, and the rake angle γ = 25 ± 10 °, characterized in that the number of teeth Z of the saw is determined by the dependence

, where D is the outer diameter of the saw.