JPH0429419B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to an impact crusher for impact crushing rocks, ores, and the like. "Prior Art" A conventional impact crusher is constructed as shown in the schematic sectional view shown in FIG. For example, raw ore is fed into the crushing chamber 3 from the raw material supply port 2 installed at the upper side of the impact crusher 1, and the raw ore is fed into the crushing chamber 3 by a hammer 6 fixed on the outer periphery of a rotating rotor 5 that rotates around the main shaft. Shattered by collision.
The raw ore thrown off by this collision is crushed by the liner _7a attached to the first repulsion plate 7 provided at the top of the crushing chamber 3, and the repelled ore is further rotated. The ball is hit by the next hitting ball 6 that comes next. The thrown ore is crushed into finer pieces by a liner _8a attached to a second repulsion plate 8 provided at the top of the crushing chamber 3. The crushed raw stone further advances from the next striker 6 to the liner _9a attached to the casing 9, and in this way, the raw stone is successively crushed along the path shown by arrow A. In the case of such a conventional impact type crusher, the impactor 6 is generally made of a hard metal such as high chromium cast iron or high manganese steel. However, with such a striker 6, the supplied raw ore to be crushed also contains similar hard raw materials, and due to repeated impact with the hard supplied raw ore, wear occurs as shown in FIG. I will do it. That is, as shown in the figure, the striking element 6, which initially had the shape shown by the dashed line, wears out one after another as shown by the broken line, and eventually wears out to the shape shown by the solid line, for example. It turns out. In order to solve this problem, a repulsive crushing impact blade has been proposed, for example, as disclosed in Japanese Utility Model Publication No. 1934/1983. ``Problem to be solved by the invention'' However, in this case, a material harder than the impact blade body is bonded to the tip of the impact blade without heat welding, and the hard material here refers to heat-treated metal. The idea and the relationship with the hardness of the rough stone are not considered at all. This cannot be said to have sufficiently solved the above-mentioned wear problem, and there was a problem in terms of crushing ability. Although the impact blade for repulsion type crushing disclosed in the above-mentioned publication improves the wear resistance of the impact blade to some extent, the hard material is usually extremely expensive, so the cost of the impact blade is lower than that of the conventional one. There is also the problem that the price increases. ``Object of the Invention'' The present invention was made in order to eliminate such conventional drawbacks, and its main purpose is to achieve low cost in a striker, and to provide a striker with excellent wear resistance when crushing raw ore. An object of the present invention is to provide an impact crusher equipped with a striking element. "Means for Solving the Problems" In order to achieve the above object, the main means adopted by the present invention is to have a rotating rotor that rotates around a main shaft provided inside a casing, and is fixed on the outer periphery of the rotor. In an impact type crusher that crushes raw ore supplied into the crushing chamber from a raw material supply port by colliding with a plurality of strikers installed and a repulsion plate attached to the casing side, the outer edge of the tip of the striker is This is an impact-type crusher that is made up of joined hard members that are harder than the raw stone and have a substantially triangular side cross-sectional shape. "Operation of the Invention" With the structure as described above, when the hard member having a substantially triangular cross section is joined to the outer edge of the tip of the striking element, the hard member is attached to the outer edge of the tip of the striking element. , a portion shaped according to its wear characteristics is reinforced by a hard member made of a wear-resistant member. In addition, the rigid member with a triangular cross section at this time is
From a cost point of view, it is possible to form a minimum volume that is cheap. "Example" Examples of the present invention will be described below with reference to FIGS. 1 to 7 to provide an understanding of the present invention. The following examples are merely specific examples of the present invention, and are not intended to limit the technical scope of the present invention. Here, FIG. 1 is a cross-sectional view of a striker installed in an impact crusher according to an embodiment of the present invention, and FIG. 2 shows the shape and dimensions of a ceramic piece joined to the striker of FIG. 1. Fig. 3 is an explanatory diagram showing the wear status of a conventional striker over time under different conditions as seen from the side, and Fig. 4 is a graph showing the wear resistance of a striker made of various hard members joined together. , FIG. 5 is a graph showing the relationship between the stress value generated in the ceramic piece and the inclination angle of the triangular cross section, and FIG. 6 is a graph showing the bending stress value generated in the ceramic piece bonded to the base material.
FIG. 7 is a graph showing the shear stress value generated at the joint surface between the base material and the ceramic piece. As shown in Fig. 1, a ceramic piece 11, which is employed as an example of a hard member, is bonded to the outer edge of the tip of a striking element base material 12 installed in an impact crusher (see Fig. 8). . In this case, the ceramic piece 11 is formed in the shape of a triangular prism with a substantially triangular side cross section, and its tip surface (impacting surface) 11 _a and the joint surface 1
The angle with 1 _b is set to 30° to 70°, and the angle between the apex 11 _c at the outer end and the bisector of that apex and the joining surface 1
The distance to the intersection with 1 _b is set to 9 mm or more (see Figure 2). As the joining method, for example, the surface of the ceramic piece 11 is fused and coated with copper, and this is silver-brazed to the striker base material 12. The shape, angle and dimensions adopted for the ceramic piece 11 will be explained below. First, in determining the dimensions of the triangular cross section of the ceramic piece _11a , the ceramic piece 11 to be joined to the outer corner of the tip of the striker is schematically shown in FIG. For example, the ceramic piece 11 is formed into a triangular prism with a height l and whose base is ΔOQR. In the figure: QR...Line tangent to the worn surface at a certain point when wear progresses...Intersection with the bisector of ∠QOR x ₀ ...Length of the line segment θ...Magnitude of ∠ORQ O' , Q', R'... are the vertices on the opposite side corresponding to O, Q, R. Next, in order to obtain data regarding the shape, the results of an investigation into how the conventional impactor 6 (see FIG. 9) wears and changes over time will be described. For this test, as shown in Figure 3a, a striker with a tip corner (dotted chain line) formed at an almost right angle, and as shown in Figure 3b, a striker with a rounded corner (dotted chain line). A batting ball with a mark on it was prepared. Changes in the side shape of these striking elements 6 over time are shown by solid lines in FIGS. 3a and 3b. As shown in Figure 3b, there are also those with rounded corners at the tip, as shown in Figure 3a.
As shown in FIG. 2, even if the tip angle is not rounded, when wear starts from the tip of the striking element 6 toward the inside, the wear progression angle α progresses at 40° to 50°. Then, after a certain period of time has passed, the wear shapes of both will almost match. This is because the angular striker (Fig. 3a) undergoes severe initial wear and wear progresses quickly. Therefore, if the ceramic piece 11 having a cross-sectional shape matching this shape is bonded to the base material 12 from the beginning, wear can be effectively suppressed. However, manufacturing a ceramic piece that exactly matches this worn shape requires a long time for machining, which increases the machining cost. In addition, since the thickness of the ceramic piece 11 at the joint end is small, the ceramic piece 11 cannot withstand the bending stress caused by the blow when the raw material is crushed, leading to breakage, and there is a risk that it will eventually break. For this reason, it is better to use a hard member with a simple shape that approximates the worn shape and does not have the problem of breaking the joint end, and is easy to process. A substantially triangular shape was selected, and the angle θ (FIG. 2) between the joint surface 11 _b and the tip surface 11 _a (see FIG. 1) was set to be large. Incidentally, data on this angle θ was investigated by performing crushing using a conventional impactor. The size of the rough stone at this time is 40 to 100 mmφ, and the rotating rotor 5 (8th
(see figure) was set at a peripheral speed of 20 to 60 m/sec. At this time, as the circumferential speed of the rotating rotor 5 increases, the length of the side of the triangle on the outer end surface of the striking element increases.
OQ (see Figure 2) has increased. This is because as the circumferential speed of the rotating rotor 5 increases, the raw stone caught at the tip of the striking element causes a slippage similar to a foul tip, and the wear position shifts backward from the tip of the striking element. Therefore, the contact point of the wear surface 12 _a at the intersection point P between the bisector of the apex angle (∠QOR in FIG. 2) of the outer end of the striker and the wear surface 12 _a and the tip surface 11 _a of the striker.
As a result of measuring the angle θ between the two, it was found that θ varies in the range of approximately 30° to 70°. Next, in examining the abrasion properties of the ceramic piece 11, various selected hard members were actually joined to the tip of the striking element, and the abrasion resistance of each was investigated. At this time, as a feed material,
We used rhyolite, which is the most abrasive rock. The wear resistance value obtained here was expressed as a wear resistance ratio, with the wear resistance of conventionally used 27Cr cast iron (shown in Figure 4) being 1. The graph shown in FIG. 4 shows this wear resistance ratio (expressed in logarithm) on the vertical axis and the Vickers hardness Hv of each hard member on the horizontal axis. In the figure: ...Si ₃ N ₄ (Silicon nitride ceramic) ...D20 (Cemented carbide-1) ...ZrO ₂ -1 (Zirconium ceramic-1) ...M20 (Cemented carbide-2) ...D40 (Cemented carbide) -3)...D25 (Cemented Carbide-4)...ZrO ₂ -2 (Zirconium Ceramic-2)...Cemented Carbide Overlay Welding...27Cr (Conventional Striker). As shown in FIG. 4, the wear resistance ratio has a constant relationship with the Vickers hardness Hv, and was 20 for the zirconia ceramic and 56 for the silicon nitride ceramic. In the case of cemented carbide, the wear resistance ratio of cemented carbide was 52, although it varied depending on the cobalt content. According to these results, the lifespan ratio L of the striking element, when the lifespan of the conventional striking element is assumed to be 1, is expressed by the following formula. L = ε _. As described above, for example, in FIG. 2, if the distance x ₀ from the apex 0 on the outside of the tip of the striker to the intersection of the bisector of the apex angle 0 and the wear surface 12 _a is decreased, the ceramic piece 11 Although the cost is reduced because the volume of the ceramic piece 11 is smaller, there is a relationship between the bending stress generated in the ceramic piece 11 and the shear stress generated at the joint, and these will be further discussed below. As a premise, when a raw stone collides with the tip of the striking element, the ceramic piece 1 bonded to the striking element base material 12
1, bending stress occurs. This is ceramic piece 11
If the bending strength (transverse strength) exceeds the bending strength of the ceramic piece 11, the ceramic piece 11 will be destroyed, so a dimensional range must be determined so that such destruction will not occur. Furthermore, since the joint surface _11b is not parallel to the striking surface _11a , shear stress is generated by the collision of the rough stones. If this exceeds the bonding strength, the ceramic piece 11 will come off from the base material 12, so dimensions must be determined to ensure that the necessary bonding area is obtained so that the ceramic piece 11 does not come off. In order to satisfy the above two points, 1 piece of ceramic
It is possible to increase the volume of 1 and increase the bonding area, but brittle materials such as ceramics have dimensional effects, so if the size exceeds a certain limit,
Strength is significantly reduced. Naturally, the size of the ceramic piece 11 must be made as small as possible in order to reduce costs. Therefore, using a calculation formula for a beam on an elastic floor having a triangular cross-sectional shape, the bending stress σ generated on the striking surface _11a was determined using θ, x ₀ and l shown in FIG. 2 as parameters.
Once θ, x ₀ and l are determined, the joint area is determined, and therefore the shear stress τ generated on the joint surface 13 is determined. Since the above calculation formula and its calculation procedure are well known, they will be omitted, but theoretically, as l becomes larger, the bonding area increases. At this time, the shearing stress τ decreases, but the bending stress σ increases, causing the ceramic piece 11 to crack. Also, as the length x ₀ increases, the bending stress σ
Although the shear stress τ and the shear stress τ are both reduced, the volume of the ceramic piece 11 becomes larger, resulting in an increase in cost. Regarding ∠ORQθ, as shown in Figure 5, the bending stress σ is maximum when θ is approximately 25°, and when θ is 50°
It reaches its maximum at ~60°, and the shear stress τ reaches its maximum. In addition, in Figure 5, x ₀ (see Figure 2)
= 10 mm, l (see the same figure) = 30 mm, and when the length x ₀ and the length l of the ceramic piece 11 are changed, the bending stress σ and the shear stress τ
The stress values of change, but the value of θ when they reach their maximum value does not change much. However, when l<20 mm, the value of shear stress τ becomes significantly large.
Note that σ ₀ in FIG. 5 is a correction value for the bending strength (flexural strength) of zirconia ceramic (ZrO ₂ ). Figure 6 shows the length when θ=45° and l=30mm.
It is a graph showing the relationship between x ₀ and bending stress σ. As can be seen from this, even if the length x ₀ is gradually reduced, the value of bending stress σ does not change much in the range x ₀ > 7 mm, but in the range x ₀ ≦ 7 mm, σ
The value of becomes significantly large. Further, this tendency remained the same even when the magnitude θ of ∠ORQ and the length l of the ceramic piece 11 were changed. Furthermore, Fig. 7 is a graph showing the relationship between length x ₀ and shear stress τ when θ = 45° and l = 30 mm. When x ₀ becomes 9 mm or less, shear stress τ suddenly increases. growing. From the above results, the length x ₀ is the shear stress τ
The value of the bonding strength of the ceramic piece 11 is approximately 6 kgf/
It is necessary that x 0 be within a range not exceeding mm ² , that is, x ₀ ≧9 mm. At this time, since the value of bending stress σ is small, there is no problem in terms of bending strength. On the other hand, as an example of a hard member, when using a cemented carbide that is directly silver-brazed to the base material 12, the strength of the joint determined in the same manner as the ceramic piece 11 above is at least 20 kgf/mm ² or more. Since there is a bonding strength (shear strength), for example, even when x ₀ =5 mm, if l≧20 mm, the hard member will not come off from the base material 12 due to shear stress. Moreover, at this time, it also has sufficient strength to withstand bending stress. Similarly, for example x ₀ is 7.5mm
When set to , it can sufficiently withstand bending stress even if l is set to 15 mm. Furthermore, even when cemented carbide is used as a hard member,
Since the results of experiments and calculations conducted so far on ceramic pieces can be very approximately matched, unless otherwise specified, references to ceramic pieces are also taken to refer to cemented carbide. do. As a result of the above studies, the dimensions of the ceramic piece and the cemented carbide piece used for the hard member of the striking element were determined, and for convenience, these dimensions are summarized in Table 1.

[Table] Incidentally, a crushing test was conducted using a striker to which a hard member formed based on the materials and dimensions shown in Table 1 was joined. At this time, zirconia-based ceramic was used as the ceramic material, and rhyolite with a diameter of 100 mm was used as the crushing raw material. This striking element was attached to an impact crusher, and the circumferential speed was 60 m/sec.
The hard member did not crack or come off from the base material 12 when rotated. "Effects of the Invention" As explained above, the present invention has a rotating rotor that rotates around a main shaft provided inside a casing, a plurality of strikers fixedly installed on the outer periphery of the rotor, and a plurality of strikers attached to the casing side. In an impact type crusher that crushes raw ore supplied into a crushing chamber from a raw material supply port by colliding with an attached repulsion plate, the outer edge of the tip of the striker has a side surface that is harder than the ore and has a side cross section. This impact type crusher is characterized by being made by joining together hard members that are approximately triangular in shape, so it can achieve low cost and has a crusher with excellent wear resistance when crushing raw ore. We were able to provide the machine.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a striker installed in an impact crusher according to an embodiment of the present invention, and FIG. 2 is an explanation showing the shape and dimensions of a ceramic piece bonded to the striker of FIG. 1. Figure 3 is an explanatory side view of the wear status of a conventional striker under different conditions over time, and Figure 4 is a graph showing the wear resistance of a striker made of various hard members joined together. Figure 5 is a graph showing the relationship between the stress value generated in the ceramic piece and the inclination angle of the triangular cross section, Figure 6 is a graph showing the bending stress value generated in the ceramic piece bonded to the base material, and Figure 7 is the graph showing the relationship between the stress value generated in the ceramic piece and the inclination angle of the triangular cross section. A graph showing the shear stress value generated at the joint surface with the piece, Fig. 8 is a schematic cross-sectional view of an impact crusher equipped with a conventional impactor, and Fig. 9 is a cross-sectional view showing the state of wear of the impactor. . (Explanation of symbols), 1...Impact crusher, 2...
Raw material supply port, 4...Main shaft, 5...Rotating roller, 6
... Striker, 7, 8 ... Repulsion plate, 9 ... Casing, 11 ... Ceramic piece, 12 ... Base material, 13
...joint surface.

Claims (1)

[Claims] 1. A rotating rotor that rotates around a main shaft provided inside a casing, a plurality of striking elements fixed on the outer periphery of the rotor, and a repulsion plate attached to the casing side. In an impact crusher that crushes raw ore supplied into a crushing chamber from a raw material supply port by colliding with it, a hard piece of hard material that is harder than the raw ore and has a substantially triangular side cross-sectional shape is attached to the outer edge of the tip of the striker. An impact crusher characterized by parts being joined together. 2. The impact crusher according to claim 1, wherein the angle between the front end surface of the hard member and the joint surface is 30° to 70°. 3. The hard member is made of ceramic, and the distance from the apex of the outer end of the triangle to the intersection of the bisector of the apex angle and the joint surface is 9 mm or more. The impact crusher according to item 2. 4. Claim 1, wherein the hard member is made of cemented carbide, and the distance from the apex of the outer end of the triangle to the intersection of the bisector of the apex angle and the joint surface is 5 mm or more. Or the impact crusher described in paragraph 2.