JP2010234497A - Tip for chip saw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tip satisfying both strength against the pressing-in of tip subjected to press-fitting into a saw plate of a chip saw and wear resistance to cutting. <P>SOLUTION: In the tip, a cutting edge 9 for cutting is formed on the surface side of an end, and a press-in groove 11 having both side walls 6 is formed on the rear surface side. By press-fitting the press-in groove 11 into a tooth profile 3 formed on the saw plate 2, the tip fixed onto the saw plate 2 is improved. In the tip 5, the cutting edge 9 is formed of a highly rigid raw material with wear resistance, and the tip body 7 having the press-in groove 11 is formed of a raw material having toughness enough to bear the press-in. The tip body 7 and the cutting edge 9 are integrally formed through sintering in two-color molding, resulting in a hardness of the tip body 7 to be 500-850 HV and a hardness of the cutting edge 9 to be 900-1,200 HV. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a tip for a tip saw that is press-fitted and fixed to a tooth profile portion of an edge that is a cutting portion of a saw blade such as a band saw for sawing.

Conventionally, for example, as shown in Patent Document 1, a chip in which square groove-like press-fitting grooves having plate-like side walls are formed on both sides of a cutting edge portion for cutting is provided on both sides of a large number of tooth profile portions at the edge of a saw plate. There is known a tip saw that is press-fitted and fixed so as to be attached from the surface.
The above-mentioned tip saw is easier to attach and detach than previous tip saws that are fixed by welding, screwing, etc., so that the tip worn by use is not conspicuous and does not require highly skilled techniques for tip replacement. There was an advantage that maintenance work did not require high cost and time.

Japanese Patent No. 4148732

However, while the above-mentioned insert is required to have high hardness with wear resistance at the cutting edge, the press-fitting groove (tip body) press-fitted and fixed to the tooth profile of the saw blade has high toughness for holding the fixing force by press-fitting and press-fitting. There is a problem that it is not suitable in terms of material because it is required, that is, a hard material is damaged.
On the other hand, since it was conventionally formed with a single material such as sintered molded material such as SUS420J2 or YAP10 (carbon C = 1.5%) which is a powder high speed steel, the hardness is limited to HV500 to 850, When a high hardness material having wear resistance exceeding HV850 is used for wear resistance, there is a drawback that the chip body which is a press-fitting fitting portion is damaged.

  The tip of the present invention for solving the above-mentioned problem is as follows. First, a cutting edge portion 9 for cutting is formed on the tip surface side, and a press-fitting groove 11 having both side walls 6 is formed on the back surface side. A chip that is fixed to the saw plate 2 by press-fitting the press-fitting groove 11 to the formed tooth profile 3, and the cutting edge 9 is formed of a high-hardness material having wear resistance, and press-fitted The chip body 7 forming the groove 11 is formed of a material having toughness that can withstand the press-fitting.

  Second, the chip body 7 and the blade edge portion 9 are integrally formed by sintering by two-color molding.

  Third, the hardness of the chip body 7 is HV500 to 850, and the hardness of the blade edge portion 9 is HV900 to 1200.

  Fourth, the high-speed steel in which the tip body 7 is made to precipitate carbide in the matrix and the cutting edge portion 9 has a carbon content of 2% or more for forming carbide in the matrix, or further contains titanium nitride. It is characterized by that.

  Fifth, the relative density (value when the true density is 100%) of the tip body 7 and the blade edge portion 9 is 93% or more.

  Sixth, it is characterized in that the sintering temperature difference between the tip body 7 and the blade edge portion 9 is sintered within 70 ° C.

  According to the chip of the present invention configured as described above, a chip saw chip for cutting wood mainly for lumbering or woodworking, and press-fitting of a chip to be press-fitted and fixed to a tooth profile portion of a cutting side edge of a saw plate Since the chip body on the press-fitting groove side, which is the part, uses a material with excellent toughness, damage during press-fitting is prevented and the chip's toughness-adhering force is maintained even during cutting use after press-fitting. Hold power.

  On the other hand, when cutting wood, the cutting edge portion has high wear resistance, so that it can withstand long-time use and can maintain a long grinding distance, and the number of chip replacements can be reduced.

  In addition, since the tip of the present invention is formed by two-color molding of the cutting edge and the tip body, a chip having a uniform size, hardness and toughness can be manufactured relatively easily, and the respective toughness and hardness required for the tip body and the cutting edge portion can be obtained. In addition to being able to reliably control, by setting the hardness of the chip body to HV500 to 850 and the hardness of the cutting edge portion to HV900 to 1200, practically sufficient durability can be obtained.

  Further, in order to maintain a substantial true density between the chip body and the blade edge portion, a relative density of 93% or more is required. For this purpose, the difference in sintering temperature between the two needs to be 70 ° C. or less.

It is a partial expanded side view of the chip saw using the chip | tip of this invention. It is the whole chip | tip perspective view similarly. (A) is a side view of the chip, (B) is a rear view thereof, and (C) is a bottom view of the chip. It is an expanded side view of the state which mounted | wore the chip | tip with the chip | tip. It is the graph which compared the abrasion resistance of the chip | tip of this invention, and another chip | tip.

  The embodiment of the chip of the present invention shown in the drawings will be described in detail below. FIG. 1 is a side view of a saw saw band saw made of a chip saw 1, and there are a number of cutting edges of a saw blade 2 made of an endless band. The tooth profile part 3 and a sawdust discharge surface 4a that is curved and cut in a valley shape are formed on the cutting direction side of the tooth profile part 3.

  Chips 5 having a groove-like cross section are press-fitted and fitted along the plate direction so as to be attached from both sides to the end portions in the cutting direction of a large number of tooth profile portions 3 and fixed in a removable manner. 2 and 3, the chip 5 has a side wall 6 on both sides, a chip body 7 having a groove-like cross section having a thick bottom part, and a tip end side of the cutting surface of the bottom part 8 of the chip body 7. It consists of a plate-shaped blade edge portion 9 integrally formed in a shape inclined in a wedge shape toward the lower end of the chip (a shape in which the thickness on the blade edge side is increased).

  A relief groove 10 at the time of press fitting to the saw plate 2 is formed in the bottom corner between the side walls 6 and 6, and the side walls 6 and 6 form a press fit groove 11 for press-fitting and accommodating the saw plate 2. . Further, the shape of the cutting surface side of the chip 1 is inclined on both sides so that the front end side is wide, and the side wall 6 is also formed with a side surface inclined in rear view so that the bottom portion 8 is successively thickened, and the saw plate 2 The clamping pressure at the time of press-fitting is held. In addition, by inclining broadly toward the cutting edge side and the cutting surface side, the effect of relaxing resistance during cutting and facilitating the discharge of sawdust is also intended.

  In contrast to the shape of the chip 5, the tooth profile portion 3 of the saw plate 2 has a plurality of saw tooth profile portions 3 and 3 as shown in FIGS. A relief surface 4b is formed as a slanting surface in the direction of the gentle attack angle. Further, the surface of the tooth profile portion 3 on the cutting direction side forms a linear surface inclined in the angle of attack with respect to the cutting direction, and forms a receiving surface 4c that faces and receives the bottom surface of the press-fitting groove 11 when the chip 5 is press-fitted. is doing.

  Further, a rectangular groove-like receiving groove 4d is formed between the lower end of the receiving surface 4c and the discharge surface 4a so as to fit and receive the lower end of the bottom 8 of the chip body 7 when the chip 5 is press-fitted. . This receiving groove 4d is mainly intended to regulate the lower limit position when the chip 5 is press-fitted and, in a supplementary manner, by adjusting the fitting tolerance with the lower end of the bottom portion 8, the fixing force of the chip 5 is adjusted. The shape of the receiving groove 4d is not particularly limited to that shown in the figure.

  As described above, in the tip of the present invention, the cutting edge portion 9 needs to be a high hardness material having wear resistance, and the tip body 7 needs to be a tough material with low hardness. Further, in order to sinter different materials at the same temperature to obtain a substantially true density, it is desirable that the difference between the sintering temperatures of the respective materials is 70 ° C. or less.

  The present invention is based on high speed steel. High-speed steel is usually a material in which carbide is precipitated in a matrix of martensite and the hardness is hardly lowered even at high temperatures, but the contribution of only carbide is HV900 stopping at Vickers hardness.

Therefore, high-speed steel powder having an average particle size of 15 μm or less for injection molding and a carbon content of 2% or more or a material kneaded with titanium nitride powder was used on the high hardness material side. Thereby, the hardness whose Vickers hardness is HV900 or more was obtained.
As a result, HV900-1200 at the cutting edge portion of the U-shaped composite insertion blade, HV500-850 at the insertion portion, and a two-color molded chip having a change in hardness as a whole were obtained.

Next, manufacturing and materials of the chip 5 will be described. In the embodiment of the present invention, the chip 5 having the shape shown in FIGS. 2 and 3 was manufactured in the following manner with respect to the band saw of the saw plate 2 having a thickness of 1.05 mm.
1. Dimensions / Shape Total length 7.00 (unit of length mm, the same shall apply hereinafter)
Height 3.00
Width 1.02 of the open end of the press-fit groove 11 (allowable dimension 0.97 to 1.02)
Side wall 6 thickness 0.1
The thickness of the bottom 8 is 1.00
Cutting edge width 2.20 (allowable dimensions 2.18 to 2.22)
Blade angle 45 °
84 ° angle at both corners
Maximum thickness 0.80 on the tip side of the blade edge 9
Length 5.00 of blade edge 9

2. Manufacturing method and material Chips were manufactured by injection molding by two-color molding and sintering technology by powder metallurgy, and an electric furnace was used as the sintering furnace.

  In the above two-color molding, the high-toughness raw material powder used for the chip body 7 and the wear-resistant raw material powder used for the blade edge portion 9 are mixed and kneaded with a binder, and then in the first molding, the mold is formed in the blade edge portion 9. The compound for the blade edge is pelletized and then injected, pressed and heated to form, and in the secondary forming, this is placed at a fixed position in the forming die of the entire chip 5 and the remaining space (the chip body 7 The compound for the chip body was pelletized in the space occupied) and injected, followed by pressure and heat molding together with the blade edge portion 9.

The sintering temperature in the above case is as follows. YAP10, YAP63, and H34A are all commercial products manufactured by Hitachi Metals Precision Co., Ltd.
(1) As a result of sintering a tough material (YAP10: carbon C = 1.5%) and an abrasion resistant material (YAP63: carbon C = 2.0%) at sintering temperatures of 1245 ° C. and 1255 ° C. Good bonding without voids and gaps was confirmed.
(2) Under the conditions of a sintering temperature of 1245 ° C., a quenching temperature of 1180 ° C., and a tempering temperature of 560 ° C., there was no void at the interface between YAP10 and YAP63, and a bonding strength of 1800 N / mm ² was obtained.
(3) Under the conditions of a sintering temperature of 1255 ° C., a quenching temperature of 1180 ° C., and a tempering temperature of 560 ° C., the structure of YAP63 is martensite and there is sufficient carbide precipitation, and the wear resistance is 3.4 of the current push blade. Double results were obtained.
(4) According to the above, a molded product in which the compounds of YAP10 and YAP63 were combined without excess or deficiency was obtained. The chip after degreasing, sintering and heat treatment of the green molded body compounded by PIM (abbreviation of Powder Injection Molding) is within the allowable range of 1.00 mm between the mounting parts and the edge width 2.20 mm. Shape accuracy was achieved.
(5) As the wear-resistant material, a material using H34A (carbon C = 3.0% added with a small amount of titanium nitride) in addition to the above was molded and heat-treated under substantially the same conditions.

FIG. 5 compares the wear resistance of the products (E) and (F) of the present invention formed by the above-described method with other products including conventional chips according to the grinding distance, and was tested under the following conditions. It is a result.
(1) Test material: YAP10, YAP63, H34A
(2) Work material: S Pararam (REW: Glulam)
(3) Equipment used: Horizontal milling machine (4) Rotation speed: 1230 rpm
(5) Feeding speed: 28 mm / min
(6) Cutting amount: Cutting distance at which the wear amount reaches 40 μm (7) Evaluation method: Evaluation of the degree of wear of the cutting edge with a microscope

According to the above results, the products (E) and (F) of the present invention are inferior to the tip formed of a single H34A with wear resistance (D), but 2 than the conventional products (A) and (B). The wear resistance is double or more, and (E) is substantially equivalent to the single (C) YAP63.
As described above, the single wear-resistant materials (C) and (D) have no problem in wear resistance, but have a problem of breakage during press-fitting of the chip.

DESCRIPTION OF SYMBOLS 1 Tip saw 2 Saw board 3 Tooth profile part 6 Side wall 7 Tip body 9 Cutting edge part 11 Press-fit groove

Claims (6)

  A cutting edge portion (9) for cutting is formed on the front surface side, a press-fitting groove (11) having both side walls (6) is formed on the back surface side, and a tooth profile portion (3) formed on the saw plate (2) A chip that is fixed to the saw plate (2) by press-fitting the press-fitting groove (11), and the cutting edge (9) is made of a hard material having wear resistance and press-fitted. A chip for a chip saw in which a chip body (7) for forming a groove (11) is formed of a material having toughness to withstand the press-fitting.   The tip for a chip saw according to claim 1, wherein the tip body (7) and the blade edge portion (9) are integrally formed by sintering by two-color molding.   The tip for a tip saw according to claim 1 or 2, wherein the tip body (7) has a hardness of HV500 to 850 and the cutting edge portion (9) has a hardness of HV900 to 1200.   A high-speed steel in which the tip body (7) has a carbon content of 2% or more for further precipitation of carbide in the matrix and the cutting edge (9) in the matrix to form carbide, or further containing titanium nitride; 4. A chip saw tip according to claim 2 or 3.   The tip for a tip saw according to claim 2, 3 or 4, wherein the relative density of each of the tip body (7) and the blade edge portion (9) is 93% or more.   The tip for a tip saw according to claim 5, wherein the difference in sintering temperature between the tip body (7) and the blade edge portion (9) is sintered within 70 ° C.

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