JPH0331408Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application The present invention relates to a striker for an impact crusher that crushes rocks, ores, etc. by impact, and particularly for an impact crusher that aims to reduce the frequency of replacing the striker. Concerning the hitter.

Prior Art A conventional impact crusher is constructed as shown in the schematic cross-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 blower fixed to the outer periphery of a rotating rotor 5 that rotates around a main shaft 4. Shattered by impact by 6.

The raw stone that is thrown off by the rotating rotor 5 collides with the liner 7a attached to the first repulsion plate 7 provided at the top of the crushing chamber 3 and is crushed.
The rebounding raw stone is crushed by impact by the next hammer 6 which rotates further. Then, the thrown ore is crushed even more finely by the liner 8a attached to the second repulsion plate 8 provided at the upper part of the crushing chamber 3.

In the case of such a conventional impact type crusher, the impactor 6 formed as one piece is generally made of a hard metal material such as high chromium cast iron, high manganese cast steel, or chromium molybdenum cast steel.

However, in this type of impactor 6, since the supplied raw ore to be crushed also contains hard minerals, etc., if the impact is repeated between it and the hard supplied raw ore, as shown in FIG. It will gradually wear out like this.

That is, as shown in FIG. 9A, the tip 6a of the striker 6 whose initial shape was as shown by the solid line.
gradually wears away and deforms into a rounded shape, as shown by the plurality of broken lines in FIG. 9B.

In the conventional impact type crusher, from the viewpoint that it is uneconomical to discard the impactor 6 in this state, the impactor 6 is turned over as shown in FIG.
Use continues until wear progresses as shown by the broken line in Figure D.

[Problem that the invention attempts to solve]

As described above, in conventional impact crushers, the impactor's wear resistance was not sufficient, so when the tip of the impactor wears out and becomes rounded, it becomes difficult for the object to be crushed to collide head-on, making it difficult to crush. As the ability decreases,
The disadvantage was that the cost of replacement was high. In addition, the replacement frequency including the above-mentioned turning of the front and back is 1.5 to 3, for example, when crushing rocks for aggregate.
The work of replacing the hammer, which weighs around 100 kg, once every month was extremely demanding.

Additionally, in order to reduce the wear of the striking element, it is possible to attach a wear-resistant piece such as hard ceramics or cemented carbide to the tip of the striking element, but it is important to select the material and size and shape with wear resistance in mind. There is a problem in that simply attaching such wear-resistant pieces while ignoring the problem does not extend the life of the impactor compared to the increase in the unit cost of the impactor, and it is difficult for normal heavy-load impact crushers to do so. Not put into practical use.

Therefore, an object of the present invention is to provide a striker for an impact type crusher that has high wear resistance and can therefore be replaced less frequently.

[Means for solving problems]

The main means adopted by the present invention to achieve the above object are: a rotating rotor that rotates around a main shaft provided inside a casing; It is equipped with a plurality of strikers and a repulsion plate provided at an appropriate distance around the rotating rotor, and the raw material splashed by the rotating strikers is crushed by colliding with the strikers and the repulsion plate. In a striker for an impact crusher, at least the outermost piece of carbide among the pieces of carbide joined by thermal melting to the striker or a joining table detachably attached to the striker. This is a striker for an impact type crusher in which the circumferential thickness of the rotating rotor is increased toward the outside in the radial direction of the rotating rotor.

[Effect]

The tip of the striker, which has the greatest impact, is made of carbide material, so even after long-term use,
Since the cross-sectional shape of the striker hardly changes, a constant crushing ability can be maintained at all times, and since the distance between the outer circumference of the hammer and the chute shown at 9 in Figure 8 does not change, the raw material does not fall out from there, and the repulsion plate 〓There is no need for adjustment (conventionally required once every 7 to 10 days), and the crushing element is now in charge of crushing, which greatly reduces the load on the crusher (liner wear). Ru.

Further, since the thickness of the striking element becomes thicker toward the outer side in the radial direction of the rotating rotor, it takes a longer period of time (replacement cycle) until the striking element wears out to the point that it cannot be used. In particular, the thickness of the carbide material pieces is increased toward the outer periphery, where wear is more severe, and the thickness of the parts with less wear is decreased, reducing the amount of carbide material used and increasing the lifespan per material cost. succeeded in increasing the.

〔Example〕

Next, embodiments embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

FIG. 1 shows a striking device according to an embodiment of the present invention, and FIG. 1A is a side sectional view thereof, and FIG.
is its front view (right half only), Figure 2 a, b, c
1A and 2B are views corresponding to FIG. 1A showing modified examples of the same striking element, respectively.

It should be noted that the following examples are merely specific examples of implementing the present invention, and are not intended to limit the technical scope of the present invention.

In FIGS. 1a and 1b, the striker 10 includes a striker body 11 and a plurality of joint stands 14, 14, . and each joint table 14,1
It is composed of carbide chips 15, 15, . . . which are fixed by brazing to 4, . . . , respectively, and each joint stand 14, 14, . It is fixed freely.

The joining of the carbide chip 15 to the joining table 14 is as follows:
It is soldered using sand German braze (a clad material made by sandwiching a copper plate between two pieces of silver solder). In addition, HIP
Bonding may be performed by pressure fusion bonding using an electron beam, laser welding, or other heat fusion methods.

The carbide chip 15 is an example of a piece of carbide material, and the spigot parts 13, 13, . . . prevent the joining bases 14, 14, . . . from loosening due to impact, and
This is to prevent the bolt 17 from being subjected to a large load due to centrifugal force.

The carbide chips 15, 15, . . . and the joining tables 14, 14, . In the examples shown in Figures 1 and 2, one carbide chip is attached to one welding table, but two or more carbide chips may be attached to one welding table, and these carbide chips can be attached to one welding table. It is also conceivable that the hard tip or joint table is not divided in the radial direction and/or main axis direction of the rotating rotor.

Further, the carbide chips 15, 15, . The chip 15b is formed into a wedge shape as a whole. Although the thickness of the carbide tip 15a on the inner peripheral side is constant in the illustrated example, it may be formed into a wedge shape like the carbide tip 15b (FIG. 2a).

The tips of the carbide tips 15b, 15b, ... tend to wear out as shown by the broken line The service life of the (thick-walled part) has been extended, making it possible to use it for a long time.

The shape of the carbide chip 15 can be square in front view as shown in the figure, or it can be circular.In order to prevent stress concentration on the corner edges during rock crushing, the shape of the carbide chip 15 is approximately 4R. Chamfering is recommended. This is also effective in removing residual strain at the corners of the joint surfaces.

The material of the cemented carbide chip 15 includes all so-called cemented carbide alloys. Such cemented carbide is made of, for example, tungsten carbide WC, which is then combined with titanium carbide TiC, tantalum carbide TaC, niobium carbide NbC,
Contains a mixture of vanadium carbide VC, molybdenum carbide Mo ₂ C, titanium nitride TiN, etc., and cobalt as a binder.
Co is also widely used.

For example, K20 (JIS
By selecting B 4104), we were able to achieve a lifespan ratio/cost ratio >1.

In the case of the striker 10 shown in this example, the wear life was more than six times that of the conventional striker made of 27Cr cast iron.

However, as long as the carbide chip 15 is a brittle material, there is no guarantee that it will never break, so the number of breaks for the throughput is predicted by a damage probability calculation that takes into account rock strength and the Weibull distribution of the cemented carbide chip strength, and then the load test is carried out. Chips that would be damaged by proof tests such as these were removed in advance.

This avoided the inconvenience of the chips breaking irregularly during use, but it was also found that the number of carbide chips removed was extremely small, only a few.

On the other hand, the particle size distribution of the product is at the initial shape of the carbide chip.
It was found that the crushing capacity remained constant as the carbide tips wore out, and there was no decrease in crushing ability.

The modified example shown in FIG. 2 is designed to reduce the amount of carbide chips used and extend the wear life, making it more economical.

The striker 10a shown in FIG. 2a has an upper carbide tip 15c and a lower carbide tip 15d formed in a vertically symmetrical shape, and when the upper carbide tip 15b wears out, it is turned upside down and has a long lifespan. It was designed to double the amount.

In addition, in the striker 10b shown in FIG. 2B, the inclination of the joint surface of the upper tip 15e is increased so as to further conform to the worn shape. If the inclination of the joint surface is increased in this way, when wear progresses, the angle between the worn surface and the joint surface tends to become more acute than in FIGS. 1 and 2a, which may lead to chipping. Therefore, in this example, consideration was given to providing a chamfer on the top surface side.

In addition, the striker 10c shown in FIG. This impact crusher is suitable for use in impact crushers for adjusting the size of small particles or for making sand without worrying about damage to the feed material.

As a modification of the above-mentioned structure in which the carbide tip is directly bonded to the striker body 11, FIGS.
What is shown in the diagram will be fried. In the striker 10d shown in FIG. 3, an undivided horizontally straight carbide tip 21d is brazed to the tip of the striker body 11d. Since the collision between the striker and the raw material occurs mostly at the outermost periphery of the striker, the above-mentioned striker 10d is suitable for use in impact type crushers for particle shape adjustment or sand making with less impact. suitable for children. However, in this case, as shown in FIG. 3a, the width of the carbide tip becomes wider toward the outer periphery of the rotating rotor, as in the embodiment shown in FIGS. 1 and 2.

In the striking elements 10e and 10f shown in FIGS. 4a and 4b, the tip striking surface portions of the striking element bodies 11e and 11f are slightly protruded in the rotational direction, and carbide tips 21e and 21f having a wedge-shaped side cross section are provided at these portions. It is brazed.

As mentioned above, in the present invention, the shape of the carbide tip is wedge-shaped in cross section, with the width in the circumferential direction of the rotating rotor increasing toward the outer periphery of the rotating rotor. There is a limit shape that is permissible in terms of. Arriving at this point, the fifth
This will be explained below with reference to FIGS. 7 to 7.

That is, when an impact crusher is actually operated, wear on the carbide chips and the joint table progresses as shown in FIG. That is, in the initial stage of use, the tip end corner of the carbide tip 21g is worn like the wear surface a, and the top 22g of the welding table 20g is also gradually worn at the same time. As the use continues, the tip of the carbide tip 21g wears out as shown in b and c, and eventually the worn surface reaches the joining surface 23g with the joining table 20g, as shown in d. At this time, the top 22g of the joining table 20g is worn down to a surface that is about 15 degrees inward from the original top 22g, as shown by d'. If use continues beyond this point, the wear surface progresses to e and e'.

Figure 6 shows the change in wear shape theoretically, taking into consideration the impact frequency distribution and particle size distribution of the raw material, and assuming that the kinetic energy lost due to slipping when the raw material collides with the carbide chip is proportional to the wear rate. This was calculated by simulation, and it matches well with the actual change in wear profile shown in FIG.

In the present invention, for example, the joint surface 23 shown in FIG.
By tilting g to 23g' (10°) or 23g'' (20°), or by tilting the impact surface of the carbide tip 21f as shown in Fig. 4b, the rotation of the carbide tip can be controlled. The width of the rotor in the circumferential direction is made wider as the outer circumference of the rotating rotor increases.For example, if we consider a state in which the worn surface has progressed to the position d as shown in Fig. 5, the tip of the worn surface d The angle φ formed by the tangent f drawn from the part to the wear surface d and the joint surface is 23g → 23g' → 23
g'' (0° → 10° → 20°), the angle between the tangent f and the welding surface decreases as φ ₀ → φ ₁ → φ ₂ , and the Since the tip is at an acute angle, chipping is likely to occur due to stress concentration at the contact portion with the joint surface.

In this way, the angle of the joint surface (θ in Fig. 7) set to save the amount of carbide material used is:
It greatly affects the occurrence of chips and cracks in carbide chips.

Furthermore, when a raw material collides with a chip of thickness t with an impact force P, the tensile stress σ generated on the surface of the carbide chip can be expressed as σ=k(P/t ² ) using the finite element method. Therefore, the minimum thickness t (7th
If the thickness of the material (see figure) is made thinner than a certain level, cracks in the carbide chips will occur frequently.

From this point of view, the above minimum thickness t should be set between 2 mm and 10 mm.
Prototypes of carbide chips were made by varying the inclination angle θ of the bonding surface in the range of 0° to 30°, and experiments were conducted to determine the degree of chipping of the carbide chips. Figure 7 summarizes the results. The experimental conditions at this time are that the circumferential speed of the rotating rotor is
28m/s, raw material size 50~0mm, production volume 140t/
It was set as h.

In Figure 7 above, ● indicates that the carbide tip has cracks that cannot be used, and △ indicates that the edge of the carbide tip has chipped to a degree that does not interfere with actual crushing operation. ing. Also, ◯ indicates conditions where no chipping or cracking occurs.

As is clearly understood from Fig. 7, if the inclination angle θ of the joint surface is set to 3° to 25° and the minimum thickness t of the carbide chip is set to about 3 mm, some chipping will occur at the boundary part. It has been found that a carbide chip that can withstand long-term use can be obtained.

Further analysis of the results shown in Figure 7 above shows that
When the minimum thickness t is 3 mm, the inclination angle θ of the joint surface is
When changing the angle from 3° to 25°, some chipping occurred in all cases. This is based on the thickness limit of carbide chips, and all the chips in these cases occurred on the fractured surface side.

Furthermore, when the inclination angle θ of the joint surface was 25°, some chipping occurred when the thickness of the carbide chip was varied from 3 mm to 7 mm. This is the angle φ between the tangent f and the joint surface shown in FIG.
This is because the angle becomes acute, stress concentration occurs at the contact point with the bonding surface 23 of the upper layer of the carbide chip, and chipping occurs at this portion.

Further, as long as the minimum thickness is ensured, slightly tilting the inclination angle θ of the bonding surface increases the thickness of the outermost peripheral portion of the carbide chip, which is advantageous against cracking and chipping. When the inclination angle θ of the bonding surface is 3°, chipping occurs when the minimum thickness t is 3 mm and 5 mm, and no chipping occurs when the inclination angle θ is 5°, and when the minimum thickness t is 3 mm. This seems to be the reason why chipping occurs, but chipping does not occur when the thickness is 5 mm or more.

Therefore, from the above experimental examples, it has become clear that no cracking or chipping occurs when the minimum thickness t is 5 mm or more and the inclination angle θ of the joint surface is in the range of 5° to 20°.

The material of the carbide chip used in the above experiment was K20.

In the case of the present invention, the method of increasing the thickness in the circumferential direction by changing the cross-sectional shape of the carbide tip from the center side of the rotating rotor to the outer circumference side can be roughly divided into four methods.
When the joint surface is inclined as shown in figure a, and when the joint surface is inclined as shown in figure b
A case can be considered in which the impact surface is inclined as shown in the figure.

The case shown in Fig. 4a has already been described, but in the example shown in Fig. 4b, the joint surface 23f coincides with the radial direction of the rotor, so the cross section of the carbide chip Even if the shape is fan-shaped as in Fig. 4a, the angle φ between the tangent to the worn surface shown by the broken line and the joint surface 23f will be larger than that shown in Fig. 4a, and the chipping will be reduced accordingly. The probability of occurrence decreases. However, because the impact surface is tilted toward the center of the rotating rotor as described above, there is a possibility that rocks thrown off by this impact surface may collide with the base material of the top of the adjacent striking element attached to the rotating rotor. There is a limit to the angle of inclination of the impact surface from this point of view. According to experiments, there is no problem with the forward inclination angle of the impact surface up to about 20 degrees, but if it exceeds 25 degrees, wear is observed on the back base material of the adjacent striking element, and the upper limit is about 25 degrees. I found out something.

[Effect of idea]

As described above, the present invention includes a rotating rotor that rotates around a main shaft provided inside a casing, a plurality of strikers fixed to the outer periphery of the rotating rotor, and a plurality of strikers arranged around the rotating rotor. A striker for an impact crusher, which is equipped with a repulsion plate provided at a distance, and crushes the raw material splashed by the rotating striker by colliding with the striker and the repulsion plate, the above-mentioned impact The thickness of at least the outermost piece of carbide material in the circumferential direction of the rotating rotor among the pieces of carbide material to be heat-fused and bonded to the joining table that is detachably attached to the striker or the striking element is determined by the thickness of at least the outermost piece of carbide material in the circumferential direction of the rotating rotor. Since this is a thicker impact type impact crusher, the amount of material used can be minimized to the extent that harmful cracking of the carbide chips does not occur. The product's lifespan can be extended and, as a result, running costs have been significantly reduced compared to conventional impact crushers using high chromium cast iron.

[Brief explanation of the drawing]

Figure 1 shows a striker according to an embodiment of the present invention; Figure a is a side sectional view thereof, Figure b is a front view (right half only), and Figures 2 a, b, and c are respectively FIG. 2 is a view corresponding to FIG. 1a showing a modification of the striking element. Figures 3a and b relate to a striker according to another embodiment of the present invention;
4 shows a modified example of the striker shown in FIG. 3, FIG. Figure 6 is a conceptual diagram showing the wear status of the carbide tip obtained by calculation.
FIG. 7 is a graph showing the occurrence of cracks and chips in carbide chips obtained by various combinations of the minimum thickness of the carbide chips and the angle of inclination of the joint surfaces. Further, FIG. 8 is a side sectional view showing an example of a conventional impact crusher, and FIG. 9 is an explanatory diagram showing the progress of wear of a conventional impactor. Explanation of symbols, 10, 10a, 10b, 10c,
10d, 21d, 21g...Blower, 11, 11
d... Striker body, 13... Pilot part, 14,
20g...Joining table, 15, 15a to 15h, 21
d, 21g...Carbide chip (carbide material piece).

Claims (1)

[Claims for Utility Model Registration] 1. A rotating rotor that rotates around a main shaft provided inside a casing, a plurality of strikers fixed to the outer periphery of the rotating rotor, and a A striker for an impact crusher, which is equipped with a repulsion plate provided at a distance, and crushes raw material splashed by the rotating striker by colliding with the striker and the repulsion plate, wherein the above-mentioned blow The thickness of at least the outermost piece of carbide material in the circumferential direction of the rotating rotor among the pieces of carbide material to be bonded by heat melting to the joining table that is detachably attached to the striker A blower for an impact type crusher, which is characterized by being thicker. 2 The thickness of the piece of carbide material in the radial direction of the rotating rotor is at least 3 mm, and the angle between the fractured surface of the piece of carbide material and the surface to be joined to the joint table is 3 to 25 degrees.Claim No. 1 for Utility Model Registration A blower for the impact type crusher described in Section 1.