KR102073568B1 - Axial-type cutting head having reduced drilling deviation and torque reaction force - Google Patents

Abstract

The axial rotary cutting head according to the present invention can reduce the deflection due to the bending deflection and the torque reaction force generated during the shearing and sump operation because the drum is divided into two or more parts and each part is rotated in opposite directions. Has the advantage.

Description

Axial-type cutting head having reduced drilling deviation and torque reaction force to reduce drilling deflection and torque reaction force

The present invention relates to an axial rotary cutting head, and more particularly, because the drum is divided into two or more parts and each part is rotated in the opposite direction, due to the bending deflection and torque reaction forces generated during the shearing and sumping operations. It is for an axial rotary cutting head, which can reduce the deflection.

In addition, the present invention also relates to a method of designing such an axially rotating cutting head.

In general, the cutting head is installed in a road header, a continuous miner, a pavement miller, or the like, and is used to crush or remove rock or pavement. The cutting head includes an axial rotary cutting head (or sometimes referred to as a axial type or longitudinal type cutting head) in which the axis of the working boom and the axis of rotation of the cutting head are the same, and the drum in which the boom and the axis of rotation are orthogonal. There is a cutter (transverse type cutting head).

As shown in Figs. 1A to 1B, the axial rotary cutting head 1 has a drum 4 and a drum 4 which are rotated about the axis of rotation, the axis of rotation of which is installed on the same line as the axis of the boom 2 of the equipment. It includes a plurality of pick cutter (7) installed in the).

Typical axial cutting heads are made conical to facilitate sumping indentation. The tip part (nose part 5) is designed with a relatively small torque radius and a relatively small torque resistance, and the rear part is cut at a relatively high linear speed due to the large rotation radius, so that the rotational resistance is equal to the speed ratio (= radius r ratio). This is big. As a result, the tip 5 generates a relatively small cutting force and the rear portion generates a large cutting force.

The axial rotary cutting head 3 performs rock cutting based on a sump of a predetermined depth. At this time, the cutting operation is a primary sumping operation to press the cutting head 3 to the rock surface to a certain depth, and a second shearing operation to cut the rock by cutting to the side while maintaining the press-in depth. Classified as

2a to 2b show the sump operation of the axially rotating cutting head 3, which sums up to zero when viewed in the xy plane, as all 360 ° sides of the axial cutting head 3 are in contact with the rock surface. As a result, excavation deflection rarely occurs. However, the torque reaction force deflection occurs the most and accordingly there is a problem that the equipment itself receives a force to rotate to one side. For reference, the arrow in FIG. 2B means the cutting load acting on each pick cutter 7. Yellow arrows indicate drag force (Fd) and white arrows indicate normal force (Fn).

3 shows a shearing operation in which a quarter part of the outer circumferential surface of the axial rotary cutting head 3 is in contact with the rock, and a joint bias occurs in a downward direction in the shearing direction, thereby causing a deflection deflection. have. On the other hand, the same problem occurs in the case of the shearing operation in which half of the outer circumferential surface of the cutting head 3 contacts the rock. Accordingly, there is a problem in that the working direction of the boom must be artificially adjusted during the shearing operation, and a difference in the drilling efficiency occurs according to the skill of the operator.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object thereof is to provide an axial rotary cutting head which can reduce deflection due to flexing deflection and torque reaction force during shearing and sumping operations.

It is also an object of the present invention to provide a method for designing such an axially rotating cutting head.

In order to solve the above problems, the axial rotary cutting head 10 according to a preferred embodiment of the present invention, the drum (11) divided into at least two parts along the rotating shaft (21); And a pick cutter 7 installed in the drum 11.

The drum 11 has a nose 5 at its tip, but the circular diameter of the cross section is increased toward the rear end, and the rotating shaft 21 is parallel to the axis of the work boom 2. The divided parts rotate about the rotation axis 21, but a part of the divided parts rotates in the opposite direction to the remaining parts.

The flexural deflection and torque reaction forces generated during the shearing and sumping operations can be offset and reduced by rotating the divided portions in opposite directions.

The divided parts can be rotated by one drive motor. Some of the divided parts may be rotated in the same direction as the rotation shaft 21 and the remaining parts may be rotated by the gear assembly 20 in the opposite direction to the rotation direction of the drive motor.

Preferably, the gear assembly 20, the sun gear 22 is rotated by the rotary shaft 21 and the gear 22a is formed on the outer peripheral surface; A ring gear 23 provided around the sun gear 22 and having a gear 23a formed on an inner circumferential surface thereof; And a satellite gear 24 installed between the sun gear 22 and the ring gear 23 to be engaged with the gears 22a and 23a.

The portion may be rotated by any one of the rotary shaft 21 and the ring gear 23, the remaining portion may be rotated by any one of the rotary shaft 21 and the ring gear 23, and thus the portion And the remaining portion may be rotated in opposite directions.

Preferably, the drum 11 is divided into two parts (first and second drums 12 and 14), wherein the first and second drums 12 and 14 are rotated in opposite directions by one driving motor. Can be. It is preferable that the rotational angular velocity of the second drum 14 is slower than the first drum 12 among the first and second drums 12 and 14.

In order to minimize the deflection deflection generated during the shearing operation of the cutting head 3, the height Hp of the second drum 14, the height Ht of the drum 11, and the reduction ratio Iz of the gear assembly 20. It is preferable to satisfy the following formula.

[expression]

0.3 ≤ Hp / Ht ≤ 0.5

1 ≤ Iz ≤ 3

In addition, in order to minimize the sum of the torque reaction forces generated during the sump operation of the cutting head, the height Hp of the second drum 14, the height Ht of the drum 11, and the reduction ratio Iz of the gear assembly 20. ) Preferably satisfies the following equation.

[expression]

0.3 ≤ Hp / Ht ≤ 0.5

1 ≤ Iz ≤ 3

According to another aspect of the present invention, a method of designing an axial rotary cutting head includes: (a) dividing the drum 11 of the cutting head into at least two parts along the rotation axis 21; And (b) determining a rotational angular velocity of the divided portion.

One part of the part is rotated in the opposite direction to the other part. The steps (a) and (b) divide the drum 11 and determine the rotational angular velocity so that the bending deflection and the torque reaction force generated in the portion during the shearing operation and the sump operation cancel each other out.

The present invention provides an axial rotary cutting head capable of reducing deflection due to flexing deflection and torque reaction forces during shearing and sumping operations.

The present invention also provides a method of designing such an axially rotating cutting head.

Figure 1a is a photograph showing a rod header equipped with a conventional axial rotary cutting head.
1B is a front view showing the cutting head of FIG. 1A.
Figure 2a is a side view showing the sump operation of a conventional axial rotary cutting head.
FIG. 2B is a rear view of FIG. 2A;
3 is a rear view showing the shearing operation of the existing axial rotary cutting head.
4 is a front view showing the axial rotary cutting head according to a preferred embodiment of the present invention.
5 is a plan view showing the cutting head of FIG.
6 is a perspective view illustrating a gear assembly provided in the cutting head of FIG. 4.
7 is a side view showing a cutting head subjected to numerical analysis (illustration of the pick cutter is omitted).
8 is a graph showing the force vector according to the height Hp of the second drum during the shearing operation when the reduction ratio of the gear assembly is 1.25.
9 is a graph showing the magnitude of the force (F _abs ) according to the height (Hp) and the reduction ratio of the second drum.
10 is a graph showing the magnitude of torque reaction force according to rock strength and height Hp of the second drum.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own inventions. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only embodiments of the present invention and do not represent all of the technical idea of the present invention, various equivalents that may be substituted for them at the time of the present application It should be understood that there may be variations and examples.

The x, y, z coordinate axes shown in the drawings below are Cartesian coordinate axes, and the three axes are perpendicular to each other. This coordinate axis has been added to help understand the drawing.

4 is a front view showing the axial rotational cutting head according to a preferred embodiment of the present invention, Figure 5 is a plan view showing the axial rotational cutting head.

Referring to the drawings, the axially rotating cutting head 10 includes a drum 11 and a pick cutter 7 installed on the drum 11.

The drum 11 has a nose 5 at its tip and the diameter of the circular cross section increases as it goes down (down in FIG. 4). Thus, the drum 11 may have a conical shape. And the pick cutter 7 is installed in the outer surface of the drum 11. The pick cutter 7 may be installed to form a spiral shape on the outer circumferential surface of the drum 11. The pick cutter 7 breaks the rock (or ground) in direct contact with the rock (or ground).

The drum 11 is divided into at least two parts. The divided portions are rotated in opposite directions to each other. For example, as shown in the figure, the drum 11 is divided into a first drum 12 and a second drum 14 and the first and second drums 12 and 14 are rotated in opposite directions to each other. Can be.

Preferably, the first drum 12 comprises a nose 5 and the diameter of its cross section increases rapidly as it goes down and the diameter of its cross section increases relatively slowly as it goes down.

In the present invention, the drum 11 is divided into two or more parts, and a part of the divided parts is rotated in the opposite direction to the other parts. Hereinafter, for convenience of description, only the case where the drum 11 is divided into two parts (a first drum and a second drum) will be described. When the drum 11 is divided into three or more parts, those skilled in the art will be able to easily understand the configuration.

The first drum 12 is directly connected to the rotary shaft 21 of the cutting head 10 to rotate in the same direction as the rotary shaft 21, and the second drum 14 is connected to the gear assembly 20 to rotate the shaft 21. Can be rotated in the opposite direction. 6 shows a specific specific example of such a gear assembly 20. Gear assembly 20 may include sun gear 22, ring gear 23, and satellite gear 24.

The sun gear 22 is installed to be rotatable by the rotating shaft 21 of the cutting head 10, and a gear 22a is formed on the outer circumferential surface thereof. The rotating shaft 21 is rotated by a drive motor (hydraulic motor, etc., not shown in the figure).

The ring gear 23 is provided around the sun gear 22, and the gear 23a is formed in the inner peripheral surface. The satellite gear 24 is installed between the sun gear 22 and the ring gear 23, and is engaged with the gears 22a and 23a.

As the rotation shaft 21 is rotated by the drive motor, the sun gear 22 is rotated, and the satellite gear 24 is rotated about the sun gear 22 as the sun gear 22 rotates, thereby rotating the ring. The gear 23 rotates in the direction opposite to the rotation shaft 21. The second drum 14 is connected to the ring gear 23 to rotate in a direction opposite to the rotation shaft 21.

Table 1 below summarizes the configuration and role of the gear assembly 20.

TABLE 1

In addition, Equation 1 below is for calculating the reduction ratio of the gear assembly 20.

[Equation 1]

In the above formula,

I _Z : Reduction Ratio

Z _S : Number of gear teeth of sun gear

Z _R : Number of gear teeth of ring gear

ω _S : Angular speed of rotation of sun gear

ω _R : Angular speed of rotation of ring gear

ω ₁ : rotational angular velocity of the first drum

ω ₂ : rotational angular velocity of the second drum

로 계산될 수 있다. For example, the reduction ratio in FIG.

It can be calculated as

[Optimized Solution of Cutter Head Segmentation (Design Method to Minimize Bias of Force)]

(1) I / O variable definition

-Input variable: Cutting height of cutting head (H _p ), reduction ratio (I _Z )

Output Variables: Cutting force of the pick cutter (Fd), cutting head combined force (absolute value of deflection force)

-Home conditions

(i) Target rock: hard rock (compressive strength 180 Mpa)

             (ii) Cutting force (Fd): 10kN (indentation depth 4mm)

(iii) Vertical force (Fn) is not taken into account.

(iv) The same cutting force is applied to all pick cutters.

(v) 1/4 of the drum outer surface contacts the rock during the shearing operation (FIG. 3).

(vi) the shape and dimensions of the cutting head are the same as in FIG. 7 (Ht = 500mm)

(2) Calculation of the components of individual forces acting on the pick cutter

Since Fd is a force generated in the tangential direction of the rotating body generated at the tip coordinates (x _i , y _i ) of the specific picker, Fd is calculated as the component force (Fx, Fy) of the Cartesian two-dimensional coordinate system. The formula for calculation is the same as Fx and Fy below.

When the drum 11 is divided into two parts, but the height of the second drum 14 is Hp and the reduction ratio is Iz, the second drum 14 is rotated in the opposite direction to the first drum 12, so that the second drum The components (Fx, Fy) acting on the specific picker of (14) can be calculated by the following equation.

Tables 2 to 6 below show the calculation results of the force according to the reduction ratio Iz and Hp when 1/4 of the drum outer surface contacts the rock during shearing of hard rock. In Tables 2 to 6, F _abs represents the absolute value of the force.

[Table 2] Reduction Ratio: 1.0

[Table 3] Reduction Ratio: 1.25

[Table 4] Reduction Ratio: 1.5

[Table 5] Reduction Ratio: 2.0

[Table 6] Reduction Ratio: 3.0

8 is a graph showing a force vector according to Hp when the reduction ratio is 1.25. As shown in the figure, it can be seen that the absolute value F _abs of the force decreases as Hp increases and then becomes the minimum value at Hp = 200mm and then increases again. This means that there is an optimal split height that can minimize the deflection deflection. In consideration of the self-weight of the cutting head 10, the force vector is more preferably located in one quadrant than in the fourth quadrant.

9 shows the absolute value F _abs of the force according to the reduction ratio Iz and Hp of the gear assembly 20.

As shown in Tables 2 to 6 and FIGS. 8 to 9 above, in order to reduce the absolute value of the deflection force of the force during the shearing operation of the axial rotary cutting head 10 (that is, the bending deflection generated during the shearing operation is In order to minimize), it is preferable that the height Hp of the second drum 14, the height Ht of the drum 11, and the reduction ratio Iz of the gear assembly 20 satisfy the following equation.

[Equation 2]

0.3 ≤ Hp / Ht ≤ 0.5

1 ≤ Iz ≤ 3

If Hp / Ds and Iz are out of the above range, it is not preferable because the flexural deflection is difficult to be adjusted efficiently through the working boom. And more preferably, Iz is 1-2.

[Design method to minimize the sum of torque reaction force]

The numerical range of Hp for reducing the magnitude of torque reaction force generated when the axial rotary cutting head 10 performs the sump operation was obtained by numerical analysis for each rock strength, and the results are shown in Tables 7 to 8 below. .

TABLE 7

TABLE 8

Table 7 shows the load acting on each pick cutter according to the type of rock, and FIG. 8 shows the entire drum under the load of the pick cutter 7 while the cutting head 10 is in contact with the rock by 360 ° of the outer surface thereof. In Table 8, the magnitude of the torque reaction force (kN-m) generated when excavation with the drum height (Ht) = 500 mm inserted in the rock is shown according to Hp.

As described above, during the sump operation of the existing axial rotary cutting head 3, the torque force generated by the rotation of the cutting head 3 causes the equipment to be forced to rotate to one side. In Table 8, the first column shows Hp = 0, where there is no cutting head split (formerly axial rotary cutting head), in which case the torque reaction force is greater than that with splits (2nd to 5th column in Table 8). It can be seen that the torque reaction force is much greater.

FIG. 10 is a graph of Table 8, and it can be seen that the magnitude of torque reaction force is smallest when Hp = 200mm in all rocks (soft rock to hard rock). In addition, when Hp = 150mm or Hp = 250mm, the magnitude of the torque reaction force is large, and it can be seen that the equipment may be pulled to one side.

According to Table 8 and FIG. 10 and the like, in order to minimize the sum of the torque reaction forces generated during the sump work of the axial rotary cutting head 10, the height Hp, the drum height Ht, the gear of the second drum 14 It is preferable that the reduction ratio Iz of the assembly 20 satisfies the following equation.

[Equation 3]

0.3 ≤ Hp / Ds ≤ 0.5

1 ≤ Iz ≤ 3

If the Hp / Ds and Iz are out of the above ranges, the magnitude of the torque reaction force increases, which may cause a problem that the entire apparatus is inclined in one direction. And more preferably, Iz is 1-2.

Meanwhile, in the above description, the first drum 12 is directly connected to the rotating shaft 21 and the second drum 14 is connected to the ring gear 23, but the first drum 12 is connected to the ring gear 23. The second drum 14 may be directly connected to the rotating shaft 21. In addition, in the above, only the division of the drum 11 into two parts has been described, but the drum 11 may be divided into three or more parts, and a part of the three parts may be rotated in the opposite direction to the other parts.

1: Loader header with conventional axial rotary cutting head
2: working boom
3, 10: axial rotary cutting head
4, 11: drum
5: nose 7: pick cutter
12: first drum 14: second drum
20 gear assembly 21 rotation axis
22: sun gear 22a, 23a: gear
23: ring gear 24: satellite gear
Ds: Maximum sump depth (depth when cutting head is inserted maximum during sump operation)
Hp: height of the second drum
Ht: height of drum
Iz: Reduction ratio of gear assembly

Claims (7)

A drum 11 divided into at least two parts along the rotation shaft 21; And,
And a pick cutter 7 installed at the drum 11;
The drum 11 has a nose 5 at its tip, but the circular diameter of the cross section is increased toward the rear end, and the rotating shaft 21 is parallel to the axis of the work boom 2,
The divided parts are rotated about the rotation axis 21, a part of the divided parts rotate in the opposite direction to the other parts,
The flexural deflection and torque reaction forces generated during shearing and sumping work are canceled and reduced by rotating the divided parts in opposite directions,
The divided parts are rotated by one drive motor, a part of the divided parts being rotated in the same direction as the rotation shaft 21 and the other part is opposite to the rotation direction of the drive motor by the gear assembly 20. Rotated to,
Gear assembly 20,
A sun gear 22 which is rotated by the rotation shaft 21 and whose gear 22a is formed on the outer circumferential surface thereof;
A ring gear 23 provided around the sun gear 22 and having a gear 23a formed on an inner circumferential surface thereof; And
And a satellite gear 24 installed between the sun gear 22 and the ring gear 23 to be engaged with the gears 22a and 23a.
Axial rotary cutting head, characterized in that the portion is rotated by the rotary shaft (21) and the remaining portion is rotated by the ring gear (23). delete The method of claim 1,
The drum 11 is divided into first and second drums 12 and 14, and the first and second drums 12 and 14 are rotated in opposite directions by one driving motor.
Axial rotary cutting head, characterized in that the rotational angular velocity of the second drum (14) is slower than the first drum (12) of the first and second drums (12) (14). The method of claim 3,
Reduction ratio of the height Hp and the drum height Ht of the second drum 14 and the gear assembly 20 in order to minimize the sum of the bending deflection generated during the shearing operation of the cutting head and the torque reaction force generated during the sumping operation. (Iz) is an axial rotational cutting head, characterized in that the following formula.
[expression]
0.3 ≤ Hp / Ht ≤ 0.5
1 ≤ Iz ≤ 3 In the design method of the axial rotary cutting head,
(a) dividing the drum 11 of the cutting head into at least two parts along the rotation axis 21; And,
(b) determining a rotational angular velocity of the divided portion;
The drum 11 has a nose 5 at its tip, but the circular diameter of the cross section is increased toward the rear end, and the rotating shaft 21 is parallel to the axis of the work boom 2,
A part of the part is rotated in the opposite direction to the other part,
Steps (a) and (b) divide the drum 11 and determine the rotational angular velocity so that the bending deflection and the torque reaction force generated in the portion during the shearing operation and the sump operation cancel each other out.
The drum 11 is divided into first and second drums 12 and 14, and divided into a first drum 12 and a second drum 14 including a nose 5.
The first drum 12 and the second drum 14 are rotated by one drive motor, the second drum 14 is rotated in the opposite direction to the drive motor and the second drum 14 is the first drum 12. A method of designing an axial rotary cutting head, characterized in that the rotational angular velocity is slower than). delete The method of claim 5,
Reduction ratio of the height Hp and the drum height Ht of the second drum 14 and the gear assembly 20 in order to minimize the sum of the deflection deflection generated during shearing of the cutting head and the torque reaction force generated during the sumping operation. (Iz) is a design method of the axial rotational cutting head, characterized in that the following formula.
[expression]
0.3 ≤ Hp / Ht ≤ 0.5
1 ≤ Iz ≤ 3

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