JP2004183416A - Wear-resistant composite cutting edge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a wear-resistant composite cutting edge to have effective excavating performance to a situation where the crack development of a rock bed cannot be expected by changing a viewpoint from conventional cutting edges. <P>SOLUTION: This wear-resistant composite cutting edge 1 for excavating sediment, a rock, or the like has an upper face 2, a bottom face 3 and opposed side faces 4, a cutting edge tip 5 formed at the tip part, and a fitting part 6 mountable to a working machine, on the proximal end side. In this case, hard wear-resistant layers 7 are formed only at the bottom face 3, at both side end parts in a cross direction in a required range. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cutting edge mainly used for a ripper point and the like, and more particularly to excavating a ground where a crack hardly occurs even when a rock penetrates the cutting edge during ripping such as a soft rock layer. And a wear-resistant composite cutting edge having a function of extending the life.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a construction machine for excavating earth and sand such as a bulldozer, a cutting blade for excavation is detachably mounted as a ripper point, for example, at a tip of a ripper device. Since such cutting blades are used for excavation and crushing work by penetrating the ground or rock, etc., they are intensely rubbed against earth and sand and rocks. Have been. For this reason, when the replacement frequency increases, the work efficiency is reduced, and at the same time, the cost of parts is increased.
[0003]
Regarding the prior art as such a cutting edge for excavation, wear resistance due to hardfacing etc. in the widthwise middle portion leaving both sides from the cutting edge of the cutting edge of the hardened and tempered low alloy steel to the middle portion. A cutting blade in which layers are arranged is known (Patent Document 1). There is also known an excavating cutting blade in which a hard particle that extends rearward from a cutting edge of the cutting blade is provided at a central portion of an upper surface of the cutting blade to form a hardened wear layer (Patent Document 2). Further, there is another one disclosed in Japanese Patent Application No. 2002-255002, which is a prior application of the present applicant.
[0004]
In the techniques disclosed in Patent Document 1 and Patent Document 2 or the prior application, the cutting edge is worn and sharpened for the purpose of improving the wear life of the cutting edge for excavation and maintaining excellent work performance (penetration). A hard wear-resistant layer is provided. What is common in those prior arts is that as shown in the schematic diagram of FIG. 6A, the wear of the central portion of the cutting edge 50 for excavation is suppressed, and the pointed shape when viewed from the near side of the blade 52 is shown. The purpose is to control the wear shape. For this purpose, a hard wear-resistant layer 53 is arranged at the center of the front (upper) surface 51. In other words, by leaving the central portion of the front (upper) surface 51 and wearing it around preferentially, it is intended to suppress the increase in the contact area and maintain the penetration.
[0005]
[Patent Document 1]
Japanese Patent Publication No. 6-501076 [Patent Document 2]
JP-A-8-53860
[Problems to be solved by the invention]
However, when the excavation work site is a soft rock layer, there is a problem with the cutting edge according to the above-mentioned prior art. Soft rocks are generally sedimentary soft rocks with a uniaxial compressive strength of about 20 MPa or less, and are in the process of becoming hard rocks due to densification and diagenesis of sedimentary soils. Weak sedimentary soft rock; (3) weathered hard rock or thermo-metamorphic hard rock in the process of becoming soil due to faulting, folding, weathering, hydrothermal action, etc. (according to the Geotechnical Engineering Handbook). The above-described cutting edge (ripper point) according to the prior art, which is used to rip hard rock ground and rips hard rock ground to enhance the functionality (penetration), is inferior in practical use. .
[0007]
In other words, when the rock is hard, once the cutting edge penetrates, the crack spreads to some extent, and thereafter, the rip work proceeds while the crack is relatively easily expanded by traction, and the rock can be crushed. For this reason, work efficiency can be maintained as long as penetration can be maintained by suppressing an increase in the contact area. However, where the rock is weak and the crack does not spread even when the cutting edge penetrates, such as a soft rock layer, it can be considered that the cutting edge of the above technique is not suitable.
[0008]
In addition, as shown in a schematic diagram of FIG. 6B, the excavating cutting blade 50 generally used in the ripping operation has a substantially wedge shape when viewed from the side. Its thickness is significantly increased. On the other hand, in the cutting edge according to the prior art, an increase in the contact area is suppressed by reducing the width. However, when the width of the contact surface is small, the area where the cutting edge contact surface is scratched by one ripping operation. And the crushing efficiency decreases. Therefore, there is a problem that workability is significantly reduced.
[0009]
In order to solve such a problem, the present invention is configured to provide an effective excavation performance in a situation in which crack propagation in a rock mass cannot be expected by changing a point of interest from a conventional cutting edge. It is an object of the present invention to provide a wear composite cutting blade.
[0010]
[Means for Solving the Problems and Functions / Effects]
In order to achieve the above-mentioned object, the wear-resistant composite cutting edge according to the present invention comprises:
A wear-resistant composite cutting blade having a top surface, a bottom surface, opposed side surfaces, a cutting edge formed at a distal end, and a fitting portion that can be attached to a working machine at a base end side, wherein a hard wear-resistant layer is formed only on the bottom surface. Are formed.
[0011]
According to the present invention, by disposing the hard wear-resistant layer only on the bottom surface of the cutting blade, the hard wear-resistant layer arranged on the bottom surface in the width direction by excavation work wears the upper surface of the cutting blade first. Because it is maintained, the cutting edge can be excavated in a wide and thin state like a hoe, and the crushing efficiency of ripping work on soft rock ground can be increased. Further, since the hard wear-resistant layer disposed on the bottom surface is gradually worn from the front side which is the base material, the hard wear-resistant layer does not peel off by use and has an effect of extending the wear life. In the present invention, the upper surface corresponds to a portion to be a front surface in use, and the bottom surface corresponds to a portion to be a rear surface in use.
[0012]
In the above invention, the hard wear-resistant layer disposed on the bottom surface is preferably in a range from a cutting edge in a longitudinal direction of the bottom surface to at least a vicinity of a wear limit length. In this way, the self-wear characteristics are controlled, the upper surface is worn first, and the hoe-like shape is maintained with the blade width wide up to the excavation limit, and the excavation function is secured and it can be used effectively. can get.
[0013]
Further, in the above invention, the hard wear-resistant layer disposed on the bottom surface is preferably formed in a region along both side edges in the width direction of the bottom surface. In this way, even if the cutting edge is worn, since the hard wear-resistant layers are present on both side edges, a wide cutting edge can be maintained, and the area where the cutting edge contact surface is scratched by one ripping operation can be reduced. Since it becomes wider and more stress can be applied to the bedrock, the effect that the crushing efficiency can be maintained to the maximum can be obtained.
[0014]
Further, in the above invention, the hard wear-resistant layer disposed on the bottom surface is preferably formed in a front end region of the bottom surface and a region along both lateral ends in the width direction. In this case, even when worn, the cutting blade having a wide and thin shape can be maintained, and the wear of the cutting edge can be further delayed, so that the effect of further extending the wear life can be obtained.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, specific embodiments of the wear-resistant composite cutting blade according to the present invention will be described with reference to the drawings.
[0016]
FIG. 1 shows a side view (a), a plan view (b), and a bottom view (c) showing a ripper point of the first embodiment.
[0017]
A description will be given of a wear-resistant composite cutting blade according to the present embodiment that is used as a ripper point of a ripper device attached to a bulldozer.
[0018]
As shown in FIGS. 1A to 1C, the ripper point 1 has a top surface 2 and a bottom surface 3, side surfaces 4 opposed to both sides thereof, and a cutting edge formed by intersecting the top surface 2 and the bottom surface 3. 5 and a fitting portion 6 is formed at a base end opposite to the cutting edge 5 to a shank (not shown) which is a working machine member of the bulldozer. Hard wear-resistant layers 7 are arranged from the cutting edge 5 to the entire required area of the distal end portion 3a of the bottom surface 3 and to the required width in both directions from the distal end portion 3a of the bottom surface 3 to the proximal end direction. It is. Reference numeral 8 in the figure is a mounting pin hole.
[0019]
The hard wear-resistant layer 7 is built up by, for example, supplying hard particles having a particle size of about 0.5 to 4 mm to a weld pool of a welding material using an arc electrode. In this case, the thickness of the hard wear-resistant layer 7 is increased so as to be about 6 mm. As the hard particles used for forming the hard wear-resistant layer, those mainly containing carbide are preferable. Examples of the carbide include TiC, ZrC, HfC (group IVB), VC, NbC, TaC (group VB), Mo2C, W2C, and WC (group VIB).
[0020]
In addition, since both sides of the hard wear-resistant layer 7 disposed on the bottom surface 3 are used at an inclination angle θ of the axis a with respect to the ground plane A of about 45 ° when normally used as the ripper point 1, The initial state in this state is set so as to reach a position corresponding to the wear limit length La relative to the work surface in the initial state. The wear limit length La is about 1/2 L from the cutting edge in the full length L at the ripper point 1 having the shape shown in FIG. However, the wear limit length is not specified by the numerical values.
[0021]
In setting the wear limit length La, the fitting portion 6 is exposed when the upper surface 2 (the front surface in use) is retracted due to abrasion during a ripping operation. It defines the limit at which the arrangement of 7 is useless.
[0022]
The width w of the hard wear-resistant layers 7, 7 arranged along both sides of the bottom surface 3 (rear surface when used) is practically about 1/4 to 1/3 of the blade width W. Preferably it is. As described above, the arrangement length is substantially L / 2 from the cutting edge to the position set as the wear limit length La.
[0023]
By arranging the hard wear-resistant layer 7 in a strip shape along the front end portion 3a and both side end portions of the bottom surface 3 in this way, a portion other than the bottom surface 3 where the hard wear-resistant layer 7 is arranged during excavation work ( The upper surface 2) is rapidly worn and gradually becomes thinner, leaving the hard wear-resistant layer 7 on the bottom surface 3 side. In other words, the wear shape is controlled in a state where the upper surface 2 is scraped off. Therefore, the edge 5 of the cutting edge (the ripper point 1) becomes thinner with its edge width W, and is formed just like a hoe, and stress is applied to soft rock ground while maintaining intrusion. To increase the crushing efficiency.
[0024]
Even if the abrasion progresses and the tip portion 3a wears out, since the hard abrasion resistant layers 7, 7 are arranged in a belt shape on both side ends, the change of the abrasion state is additionally shown in FIG. As described above, even if the front surface (upper surface 2) side is preferentially worn, the entire blade width is maintained by the hard wear-resistant layers 7, 7 disposed on the rear surface (bottom surface 3) side, so that the front surface becomes thinner. It is kept in a hoe shape, and gradually wears out, but the rear surface is worn with a delay. Therefore, the crushing efficiency is maintained up to the wear limit length position.
[0025]
In order to confirm the effectiveness of the cutting edge of the present embodiment configured as described above, a result of an actual vehicle test using two types of ripper points in addition to the ripper point of the present embodiment and the conventional product is shown. 3 (a) and 3 (b). The other types of ripper points (test product 1 and test product 2) used in this test are the same as the cutting edge of the present embodiment, such as the outer dimensions and base material. As shown in FIG. 4 (a), as the test product 1, the upper surface 2a of the ripper point 1a has a cutting edge 5a and a center portion connected thereto, and the lower surface 3a 'has a cutting edge 5a and a center portion connected thereto. Each of the test pieces 2 has a hard wear-resistant layer 7 ′, and as shown in FIG. 4B, a required area from the cutting edge 5 b of the upper surface 2 b of the ripper point 1 b to the base end side is required. A hard wear-resistant layer 7 "arranged over the entire blade width was used. In this test, a general ripping operation was performed. The distance of one ripping operation is about 30 m.
[0026]
In this comparative test, the conventional product has a high wear rate and becomes unusable in a short period of time, whereas the test product 1 has a very good wear life, but has poor workability (excavation property) and cannot be used on the way. I became intolerant and stopped the test. In addition, the test product 2 did not have a great difference in the wear life from the conventional product because the hard wear-resistant layer peeled off in the middle. Moreover, as the wear progressed, the excavation was poor, though there was no problem in the penetration. The ripper point 1 of the present embodiment has a durability which is about twice as large as that of the conventional product in terms of durability because the abrasion rate is lower than that of the conventional product and the hard wear-resistant layer does not peel off. Durability (abrasion resistance) is recognized, and even if wear progresses, the tip is kept thin and wide, excavation is good, average work efficiency is improved in proportion to it, and it is remarkably good I understand.
[0027]
In addition, the ripper point 1 of the present embodiment is effective work that ensures the excavation ability as compared with the conventional product and the test products 1 and 2, as seen from the graph of the average work efficiency shown in FIG. It turns out that the time is much better. In short, the efficiency of the conventional product and the test products 1 and 2 are less than 1 in a short time in comparison with the ripper point of the present embodiment used for the comparison test, but the ripper point of the present embodiment is twice as large as those. It can be seen that it possesses an excellent function that it effectively lasts for the above working hours. The average work efficiency (times / minute) indicates the average number of times of ripping work in each work time section, and the ripping work distance per time is about 30 m.
[0028]
In the above-described embodiment, a long rib is formed at the center in the width direction of the cutting blade. However, the present invention can also be applied to a case where there is no center rib provided on the lower surface 3. If necessary, a hard wear-resistant layer may be provided on the front surface within a range where the workability is improved (up to the limit length where excavation is good).
[0029]
As described above, the wear-resistant composite cutting edge of the present invention is effective as a ripper point. Not only such a ripper point, but also as a cutting edge 21 of a ripper bucket 20 as illustrated in FIG. Can be used. Alternatively, it can be used for the tooth of the excavation bucket as needed.
[Brief description of the drawings]
FIG. 1 is a side view (a), a plan view (b), and a bottom view (c) showing a ripper point of the present embodiment.
FIGS. 2A and 2B are an explanatory diagram (a) of a usage state of a ripper point of the present embodiment and a plan view (b) illustrating a worn state.
FIGS. 3A and 3B are a graph (a) showing abrasion resistance and a graph (b) showing average working efficiency of a comparison test result of a conventional product and a test product with the present embodiment.
FIGS. 4A and 4B are diagrams showing test products used for a comparison test.
FIG. 5 is a diagram showing a ripper bucket and its cutting blade.
FIG. 6 is a schematic diagram (a) showing a plane of a conventional ripper point and a schematic diagram (b) showing a mode in which the thickness increases with progress of wear.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ripper point 2 Top surface 3 Bottom surface 3a Bottom end portion 5 Cutting edge 6 Fitting portion 7 Hard wear-resistant layer a Axis A Ground plane

Claims (4)

A wear-resistant composite cutting blade having a top surface, a bottom surface, opposed side surfaces, a cutting edge formed at a distal end, and a fitting portion that can be attached to a working machine at a base end side, wherein a hard wear-resistant layer is formed only on the bottom surface. A wear-resistant composite cutting blade characterized in that a cutting edge is formed. The wear-resistant composite cutting blade according to claim 1, wherein the hard wear-resistant layer disposed on the bottom surface ranges from a cutting edge in a longitudinal direction of the bottom surface to at least a vicinity of a wear limit length. The wear-resistant composite cutting blade according to claim 1, wherein the hard wear-resistant layer disposed on the bottom surface is formed in a region along both side edges in the width direction of the bottom surface. The wear-resistant composite cutting blade according to claim 1, wherein the hard wear-resistant layer disposed on the bottom surface is formed in a front end region of the bottom surface and a region along both side ends in the width direction.

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