JPS6326185Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a roller mill that can be applied to a vertical roller mill.

In the conventional vertical roller mill shown in FIG. 1, a material to be crushed 4 is caught between a plate 2 rotating around a vertical drive shaft and a roller 3. The object to be crushed 4 is crushed by the force applied by the rollers 3 and the slippage caused by the shapes and postures of the rollers 3 and the plate 2.

However, the accumulated layer of the material to be crushed 4 is
Therefore, when a force is applied by the roller 3 to the accumulated layer of the material to be crushed 4, the roller 3 receives a reaction force in proportion to the thickness of the accumulated layer.

In addition, the slip between the plate 2 and the roller 3 can be determined from the shape of the roller 3 by finding the rolling point at which the circumferential speed of the plate 2 and the roller 3 are the same, and the slip rate is shown in Figure 5. The distribution becomes as follows, and the maximum value is obtained at the outer edge 5 of the dish 2 shown in FIG. Note that the slip rate is defined as {(roll circumferential speed−dish speed)/roll circumferential speed}.

Therefore, as shown in FIG. 3, the wear of the roller 3 occurs near the outer edge of the plate 2, where the reaction force from the object 4 to be crushed is maximum and the slippage between the plate 2 and the roller 3 is maximum. It is known that it becomes large at position 5.

In other words, excessive local wear of the roller 3 occurs at the position where the reaction force received from the layer of the material to be crushed 4 is maximum and
This is largely due to the overlapping of the positions where the slip between the roller 3 and the roller 3 is at its maximum.

Furthermore, if the wear of the roller 3 exceeds a certain value, the grinding capacity of the mill decreases, and if the local wear exceeds a certain value, it is necessary to replace the roller 3 or repair the worn part.

The present invention aims to eliminate the above-mentioned conventional drawbacks, and aims to equalize the sliding rate between the table and the rollers to prevent excessive local wear of the rollers, and prevent a decrease in the capacity of the roller mill due to excessive local wear of the rollers. The purpose is to

To achieve this objective, the present invention provides a roller mill equipped with a table that rotates around a vertical drive shaft, and a plurality of rollers that rotate while being pressed against the top surface of the table and crush the pulverized material together with the table. is divided into a plurality of parts within a single slope in the axial direction, and is formed into a truncated cone shape with an inner roller diameter smaller than an outer roller diameter, and each roller is individually rotatably mounted on a roller shaft. Accordingly, it is an object of the present invention to provide a roller mill capable of dispersing the positions where the maximum slip occurs between the table and the rollers.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 6 is a front sectional view showing only a portion of a roller mill showing an embodiment of the present invention, and Fig. 7 is a slide rate distribution diagram between the plate and the roller.

In the figure, rollers 6 and 7, which are pressed against a plate 2 that is rotationally driven by a vertical drive shaft 1 and are driven by the rotation of the plate 2, are divided within a single slope in the axial direction, and the inner roller diameter is Each roller is formed into a truncated cone shape smaller than the diameter of the outer roller, and each roller is attached to a common rotating shaft 8 via a bearing 9 so as to be able to rotate independently. Note that the roller can be divided into a plurality of parts and each of them can be independently attached to the same shared rotating shaft, but this example shows an example in which the rollers are divided into two, such as rollers 6 and 7.

Since the present invention is configured as explained in detail above, it is possible to avoid the point where the maximum slip rate between the table and the roller overlaps with the position where the reaction force of the roller is maximum.
Excessive local wear of the rollers can be prevented.

Furthermore, the slip rate distribution between the table and the roller can be made uniform, and the entire length of the roller can be used effectively. Furthermore, by preventing excessive local wear of the roller, the wear limit of the roller can be set to a large extent, making it possible to significantly extend the life of the roller.

In addition, the vertical crushing device previously proposed in Japanese Patent Application Laid-open No. 58-36651 has a small diameter roller on the outside of the crushing table and a large diameter roller on the inside to remove powder that cannot be crushed by the large diameter roller. According to this device, the small-diameter roller has a large crushing capacity, but the small-diameter roller rotates at a high speed because it is in contact with the outer periphery of the grinding table. Therefore, there is a drawback that wear of the small diameter roller increases.

From the perspective of reducing roller wear, it is correct to lower the roller load surface pressure in areas where the circumferential speed is high. In this invention, the inner roller diameter of the split roller is formed into a truncated cone shape, which is smaller than the outer roller diameter, so the large diameter roller is in contact with the outer periphery of the table, which has a high circumferential speed, and the rotation speed of the large diameter roller is Since it is not as large as in the conventional example, the surface pressure of the outer peripheral portion where the circumferential speed is high is reduced. Therefore, it is possible to maintain the same crushing ability as with a single conical roller, and it is possible to reduce differential slip on the roller surfaces, thereby reliably reducing roller wear.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing a conventional vertical roller mill, Fig. 2 is a front view showing the state of accumulation distribution on the plate of the material to be crushed, Fig. 3 is a front view showing the wear state of the roller, Fig. 4 is a front sectional view showing a part of a conventional vertical roller mill, Fig. 5 is a distribution diagram of the slip rate between the plate and the roller in the case of Fig. 4, and Fig. 6 is a diagram of a roller mill showing an embodiment of the present invention. FIG. 7, which is a front sectional view of only one part, is a slip rate distribution diagram between the plate and the roller in the case of FIG. 6. Explanation of the main parts of the figure, 1... Vertical drive shaft, 2... Dish (table), 6, 7... Roller, 8... Rotating shaft, 9...
bearing.

Claims (1)

[Scope of utility model registration request] In a roller mill equipped with a table that rotates around a vertical drive shaft, and a plurality of rollers that rotate while being pressed against the top surface of the table and pulverize the pulverized material together with the table, the rollers are rotated within a single gradient in the axial direction of the mill. 1. A roller mill characterized in that the roller mill is divided into a plurality of parts, each of which is formed into a truncated cone shape with an inner roller diameter smaller than an outer roller diameter, and each roller is individually rotatably mounted on a roller shaft.