JP5622595B2 - Saw blade for electric saw - Google Patents

Description

  The present invention relates to a saw blade for an electric saw used for an electric saw that reciprocates a saw blade.

  An electric saw that reciprocates a saw blade is widely used as a cutting device for cutting a workpiece such as a metal pipe. As a saw blade used for this electric saw, a so-called bimetal saw blade using a high-speed tool steel as a tooth tip and a tough alloy steel as a body portion is generally used. Also, in terms of shape, the cutting noise can be reduced by setting the pitch of the tooth tip of the saw blade to unequal pitch, or the cutting amount of the clam teeth can be changed to subdivide the chips, Saw blades that reduce cutting resistance acting on the saw teeth have been put to practical use. In general, a saw blade that has been bent by a tooth tip in the left-right direction is subjected to cutting force on the side opposite to the set-up direction when the workpiece is being cut. If it is not taken, it will be a factor of cutting. In addition, as shown in Patent Document 1, a line connecting the tooth tips of the teeth with respect to a straight line connecting the tip of the most advanced tooth and the tooth tip of the most proximal tooth in the electric saw blade is a tooth root. What is comprised so that it may curve toward a direction is known.

JP 2001-179536 A

  Here, the structure of a conventional saw blade as shown in Patent Document 1 will be described with reference to FIGS. FIG. 1 is a partially enlarged view showing the arrangement of teeth of a conventional electric saw blade, wherein (1) is a side view and (2) is a bottom view. The saw blade 1 is bent in the right direction with the straight teeth 3 that are not bent in the thickness direction of the saw blade body 2 and the left set teeth 4a and 4b that are bent in the left direction. Has the right set teeth 5a, 5b done. The left and right set teeth in the horizontal direction W1 are constant, and the tooth tip pitches Pa to Pe of the saw teeth are all different pitches, so-called unequal pitches. Between the straight tooth 3 and the next straight tooth 3, four set teeth are arranged.

  According to the conventional saw blade 1, since the pitches of the left and right set teeth are unequal, the cutting amount differs between the left and right teeth. This means the difference in cutting resistance received between the left and right, and the difference in the amount of saw blade swinging between the left and right due to the cutting resistance means that straightness during cutting is lost and bending is likely to occur. This indicated that the cutting efficiency and work quality were lowered, and there was a need for improvement.

  Also, when cutting a pipe with an electric saw, as shown in FIG. 2, the contact distance L1 between the workpiece 7 and the saw blade 1 becomes long soon after the start of cutting, and the saw blade with a narrow tooth pitch causes clogging. As a result, the cutting efficiency is reduced and heat is generated, which causes premature tooth wear. Therefore, it is desirable to set a wide tooth pitch for cutting at this point.

  When the cutting is advanced as shown in FIG. 3 and the saw blade tip 6 reaches the pipe inner diameter 7a, the contact distance L2 between the workpiece 7 and the saw blade 1 gradually decreases, and the saw blade tip reaches the vicinity of the center of the pipe diameter. The contact distance L2 becomes the shortest. At this time, if the tooth pitch is wide, the amount of cut will be excessive, the impact received by the tooth will increase, and the tooth tip will be chipped and vibration during cutting will increase. Is preferably set narrowly.

  As shown in FIG. 4, when the workpiece 7 is further cut, the contact distance L3 between the workpiece 7 and the saw blade 1 gradually increases, and the cutting conditions are the same as soon as the cutting starts shown in FIG. In this way, in the case of pipe cutting, an appropriate tooth pitch greatly changes in one cutting operation, so a single tooth pitch saw blade is disadvantageous compared to an unequal pitch blade.

  As explained above, the optimum conditions for the pitches of the left and right set teeth 4a, 4b, 5a, 5b and the pitch of the straight teeth 3 differ depending on the positional relationship between the saw blade 1 and the work 7, so how to set them It is difficult to do.

  The present invention has been made in view of the above background, and is to achieve a saw blade for an electric saw having an unequal pitch blade capable of cutting a workpiece such as a pipe without impairing cutting efficiency and cutting quality.

  Another object of the present invention is to realize a saw blade for an electric saw that is excellent in durability while improving cutting efficiency by optimizing the type and pitch of teeth to be set.

  The purpose of the above is to provide two kinds of tooth pitch and straight teeth without set-up bending and set-up teeth set up in the left-right direction in the electric saw blade, straight teeth, left set teeth, straight teeth, right sets The teeth (the order of the left and right set teeth may be reversed) form one set pattern, and a saw blade is formed by a series of the set patterns. Further, the pitch and the amount of swing out of the left and right set teeth are all set to be the same. Further, the pitch of the straight teeth following the set teeth is set small, and the pitch of the set teeth following the set teeth is set large.

  The saw blade for an electric saw according to the present invention is used for an electric saw that reciprocates the saw blade. Since the left and right set teeth are balanced by using an unequal pitch blade, Compared with this, excellent sharpness or cutting performance and durability can be realized.

It is the elements on larger scale which show the arrangement | positioning condition of the tooth | gear of the conventional saw blade for electric saws, (1) is a side view, (2) is a bottom view. It is a figure which shows the relationship between the saw blade for electric saws of an initial stage of cutting, and a pipe. It is a figure which shows the relationship between the saw blade for electric saws in the middle of a cutting | disconnection, and a pipe. It is a figure which shows the relationship between the saw blade for electric saws and a pipe just before the end of a cutting | disconnection. It is a side view showing the whole saw blade for electric saws concerning the present invention. It is the elements on larger scale which show the arrangement | positioning condition of the tooth | gear of the saw blade for electric saws which concerns on this invention, (1) is a side view of the saw blade main body 8a, (2) is a bottom view of the saw blade main body 8a. It is a graph which shows the experimental result of the cutting | disconnection with the saw blade for electric saws which concerns on this invention, and the conventional saw blade for electric saws.

  An embodiment of the present invention will be described with reference to FIGS. In the present specification, the front, rear, left, right, and up and down directions of the saw blade 8 will be described as directions shown in the drawing. FIG. 5 is a side view showing the entire saw blade for an electric saw according to the present invention. The saw blade 8 is an elongated blade-type saw blade before and after being used in an electric saver saw (not shown), and a plurality of teeth 9 are formed on the lower portion 8b of the saw blade body 8a. It consists of various pitches. An attachment portion 8c to the electric saver saw is provided on the base end side (rear side) of the saw blade body 8a. A line (hereinafter referred to as “tooth tip line”) A connecting the tooth tips 10 of the teeth 9 is the tooth tip of the tooth 9a on the most distal side (front end side) and the tooth 9b on the most proximal side of the saw blade body 8a. It is curved so as to be convex with respect to a straight line (hereinafter referred to as “reference line”) B connecting the tooth tips.

  In this embodiment, the tooth tip line A is curved with a substantially constant curvature, and the distance from the tooth tip of each tooth 9 to the reference line B is the largest near the center of the reference line B (distance δ). It becomes small as it goes to the front end side and the base end side of the blade body 8a. The degree of curvature of the tooth tip line A that provides good cutting performance and durability varies depending on the length of the reference line B or the distance (actual blade length) from the most advanced tooth 9a to the most proximal tooth 9b. However, according to the experiment and research of the present inventor, when the actual blade length is 100 mm or more and 400 mm or less, the distance δ is preferably 12 mm or less. Specifically, when the actual blade length is 100 mm or more and less than 200 mm, the distance δ is about 0.4 to 5 mm, and when the actual blade length is 200 mm or more and less than 300 mm, the distance δ is about 1.5 to 9 mm, When the actual blade length is 300 mm or more and less than 400 mm, the distance δ is preferably about 3 to 12 mm.

  6 is a partially enlarged view showing the arrangement of teeth of the saw blade for an electric saw according to the present invention, (1) is a side view of the saw blade body 8a, and (2) is a bottom view of the saw blade body 8a. It is. In the present invention, the pitch of the saw blade 8 is composed of two types of pitches P3 and P4. P3 is a pitch corresponding to the straight tooth 9c and the length is 2.117 mm, and P4 is a pitch corresponding to the set teeth (9d and 9e) and a length is 2.822 mm. In this embodiment, the dimensional ratio between the pitches P3 and P4 is set to 3: 4, and the pitch P4 of the set teeth is set to be longer than the pitch P3. Moreover, in the conventional saw blade 1 shown in FIG. 1, the right set teeth 5b, the left set teeth 4b, the right set teeth 5a, the left set teeth 4a and a plurality of set teeth are arranged continuously from the front end side. However, in the saw blade 8 of the present embodiment, as shown in FIG. 6, one set tooth and straight tooth are alternately arranged.

  The teeth of the saw blade 8 are composed of a straight tooth 9c that is not subjected to a set process, a right set tooth 9d that is set in the left and right direction of the saw blade body 8a, and a left set tooth 9e. The amount W2 is constant. The arrangement of the teeth is configured by repeating the set pattern 12 of the straight teeth 9c, the left set teeth 9d, the straight teeth 9c, and the right set teeth 9e from the front end side. Here, the relationship between the set pattern 12 and the pitch, which are repeated sections, is arranged so that the pitch between the set teeth 9d or 9e provided behind the set teeth 9c and the set teeth 9c is P3. According to this configuration, the pitch P3 of the straight teeth 9c is narrow, and the pitch P4 of the set teeth 9d and 9e is wide. Further, the height H4 of the pitch portion is configured to be larger than H3 corresponding to the difference in pitch.

  The clam pattern 12 having the configuration shown in FIG. 6 includes straight teeth 9c, right claws 9d1, and left claws 9e1, and therefore, the straight teeth between the claws compared to the clam pattern shown in FIG. 9c is increased by one. That is, in the set pattern 12, there are two straight teeth 9c for each cutting of the right set teeth 9d and the left set teeth 9e, so that cutting is performed twice. At this time, for example, when the set pattern 12 has a single pitch that is not an unequal pitch, the cutting amount of one tooth is the same, so the cutting amount of the straight tooth 9c is the same as the cutting amount of the straight tooth 9c. More than the cutting amount of 9d and 9e.

  The unbalance of the cutting amount by each tooth also causes the load on each tooth to be unbalanced, causing tooth chipping and uneven wear, which adversely affects the life of the saw blade. Therefore, the cutting amount of the straight tooth 9c is suppressed and the left and right set teeth 9d. It is important to balance the cutting amount of 9e. Therefore, in this embodiment, the pitch P3 of the straight teeth 9c is made narrower than the pitch P4 of the set teeth 9d and 9e, and the amount of cutting of one straight tooth 9c is suppressed, so that the load applied to each tooth is made uniform. It was configured as follows. Further, according to the present invention, the interval Ps between the straight teeth 9c and the straight teeth 9c is constant at P3 + P4. Further, the interval Pw between the right set teeth 9d and the left set teeth 9e is also constant at P3 + P4, which indicates that the left and right cutting amounts are constant. As a result, the tooth run-out due to the cutting resistance applied to the left and right set teeth 9d and 9e becomes equal to the left and right, so that the straightness during cutting is kept good.

  Further, by providing two kinds of tooth pitches P3 and P4, it is possible to cope with a change in the contact distance between the workpiece 7 and the saw blade 1 during the pipe cutting shown in FIGS. Specifically, when the contact distance L1 between the workpiece 7 and the saw blade 1 immediately after the start of cutting shown in FIG. 2 is long, main cutting is performed at a portion of P4 having a wide pitch, and the P3 portion assists the cutting of P4. Do cutting. When the cutting edge shown in FIG. 3 advances to the vicinity of the center of the workpiece 7 and the contact distance L2 between the workpiece 7 and the saw blade 1 is short, the cutting depth of the teeth is cut by the teeth of the portion P3 having a narrow pitch. The impact is reduced, tooth damage can be prevented and the life of the saw blade can be extended.

  As described above, in the saw blade 8 according to the present embodiment, tooth damage can be prevented and the life of the saw blade can be extended significantly. In addition, the machinability was greatly improved. The saw blade 8 shown in FIG. 6 is configured by repeating the set pattern 12 of the straight teeth 9c, the left set teeth 9d, the straight teeth 9c, and the right set teeth 9e from the front end side, but the right set teeth and the left set teeth The arrangement may be reversed, and the pattern of the straight teeth 9c, the right set teeth 9e, the straight teeth 9c, and the left set teeth 9d may be repeated from the front end side.

  The inventors conducted a practical experiment in order to confirm that the saw blade 8 according to the present invention has better cutting performance and durability than the conventional saw blade 1. FIG. 7 is a graph showing experimental results of a cutting test between the electric saw blade according to the present invention and the conventional electric saw blade. An electric saver saw (CR13VBY manufactured by Hitachi Koki Co., Ltd.) equipped with a saw blade for an electric saw is set to a speed dial 2.5, and a pipe fixed to a vise device by hand is cut. The cutting method was a free cutting that proceeded with the weight of the electric saver saw.

  The saw blade specification used in the experiment is a combination of the tooth tip material made of high speed (for example, cemented carbide tip) 200 mm in length, the blade width 18 mm, the thickness 1.3 mm, and the tooth pitch 9 and 12 (pieces / inch). The clam pattern has straight teeth, right claws, straight teeth, and left claws, and the tooth tip has a curved shape. Here, the total length is the length in the front-rear direction of the saw blade, and the blade width refers to the length in the vertical direction when viewed in FIG. In the prototype to be compared, the tooth tip material is made of high-speed (for example, carbide chip) 200 mm in total length, the blade width is 18 mm, the thickness is 1.3 mm, the tooth pitch P3 is 12 (pieces / inch), and the tooth pitch P4 is 9 (pieces). / Inch), and the set pattern is a straight tooth, a left set tooth, and a right set tooth, and the tooth tip has a curved shape. Another commercial product, which is the comparison target, is a tooth tip material HSS (material details unknown) with a total length of 200 mm, a blade width of 18 mm, a thickness of 1.3 mm, and a tooth pitch of 10 (pieces / inch). The left and right set teeth are teeth, and the tooth tips are linear. There are two saw blades used for cutting in each specification. The pipe of the material to be cut has a 50A pipe outer diameter of 60.5 mm and a wall thickness of 3.9 mm made of SUS304. The experiment was performed until the saw blade was not cut, and the time required for cutting was measured.

  The experimental results are as shown in FIG. Invention 1 and Invention 2 in the graph are the results of the first and second saw blades 8 of the configuration shown in FIGS. Prototype 1 and Prototype 2 in the graph are the results of the first and second saw blades of the above-described electric saw for comparison. Commercial product 1 and commercial product 2 are the results of the first and second saw blades for electric saws on the market. From this experimental result, the first and second products of the invention can be cut three times, the average cutting time of the first cut is 94.5 seconds / time, and the average cutting time of the second cut is 135.5. Second / time. The number of cuttings of the prototype was one for the first and twice for the second, and the average cutting time for the first cut was 87.5 seconds / time, and the cutting time for the second cut was 141 seconds. Both of the commercially available products reached the end of their lives after being cut once, and the average cutting time was 109.5 seconds / time.

  As described above, the invention product has the most superior result in terms of life. The cutting speed for the first cut of the invention and the prototype is 7 seconds, and the prototype is superior, and for the second cut, the invention is superior with a difference of 5.5 seconds. It was. Inventive products and commercial products were superior in inventive products with a difference of 15 seconds between inventive products. From the above results, it was confirmed that the inventive product had excellent cutting performance and durability as a saw blade for an electric saw.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, in the above-described embodiment, the dimensional ratio between the pitches P3 and P4 is set to 3: 4. However, the ratio is not necessarily limited to this, and may be set to other ratios.

1 saw blade 2 saw blade body 3 straight teeth 4a, 4b left set teeth 5a, 5b right set teeth 6 saw blade teeth 7 work 7a pipe inner diameter 8 saw blade 8a saw blade body 8b lower part of the saw blade 8c (electric saver saw) 9) (the most advanced) tooth 9b (most proximal end) tooth 9c straight tooth 9d right set tooth 9e left set tooth 10 tooth tip 11 tooth base 12 set pattern A tooth tip line B reference line P3 Pitch of straight blade P4 Pitch of set blade Pw Distance between previous set teeth and next set teeth Ps Distance between previous and next set teeth L1, L2, L3 Contact distance W1 between work and saw Tooth swing amount W2 (Crust tooth) swing amount

Claims (3)

  A saw blade for an electric saw that is used for an electric saw that reciprocates a saw blade, and has two pitches, a wide tooth pitch and a narrow tooth pitch, with an unequal pitch saw blade composed of two types of saw tooth pitch. Is an unequal pitch blade in which the wide pitch and the narrow pitch are alternately arranged, and consists of straight teeth and set teeth that are swung left and right, and the arrangement is straight teeth, right set teeth, straight teeth , Left set teeth or straight teeth, left set teeth, straight teeth, right set teeth, straight teeth and set teeth are arranged alternately, the pitch of the straight teeth following the set teeth is small, and the set teeth following the set teeth An electric saw blade having a large tooth pitch.   2. The saw blade for an electric saw according to claim 1, wherein the distance between the straight teeth and the distance between the set teeth and the set teeth is configured to be equal, and the left and right swinging amount of the set teeth is constant.   The line connecting the tooth tips of each tooth is curved toward the root direction with respect to the straight line connecting the tooth tips of the most advanced tooth and the most proximal tooth. Or the saw blade for electric saws of 2.

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