Asymmetric disc cutter ring

Abstract

The invention relates to the technical field of full face rock tunneling machines, in particular to a disc cutter capable of efficiently breaking rock. The disc cutter is an asymmetric cutter ring designed by considering rock breaking lateral force, the outer edge angle of the disc cutter is increased, and the inner edge angle of the disc cutter is reduced, so that the disc cutter is more suitable for balancing the lateral force in the tunneling operation process. And the strength of the blade part of the disc-shaped hobbing cutter is improved while the actual rock breaking characteristic is met, abnormal failures such as tipping, string grinding and blade collapse are basically eliminated, and the service life of the disc-shaped hobbing cutter is prolonged.

Description

Technical Field

[0001] The invention patent belongs to the field of disc cutters for full-section rock tunneling machines, and in particular relates to a disc cutter for efficient rock breaking. Background Art

[0002] At present, the disc cutters widely used in rock-breaking tools of full-face tunnel boring machines (a general term for full-face rock tunnel boring machines - TBMs and shields - Shields) are generally symmetrical about the blade plane perpendicular to their rotation axis, which are called symmetrical-blade disc cutters; this type of cutter does not meet its actual rock-breaking characteristics, and has serious abnormal failures such as chipping and string wear, and has a short life. Asymmetrical-blade (or wedge-shaped) disc cutters designed according to the velocity vector of the rock penetration bisecting the disc cutter blade angle have the characteristic of weak blades, which affects the strength of disc cutters with a small installation radius, and even causes "blade collapse", reducing the efficiency of TBM and Shield operations. Summary of the invention

[0003] The invention substantially eliminates abnormal failures such as chipping of the rock-breaking disc-shaped hob, string wear, and "blade collapse", and increases the life of the rock-breaking disc-shaped hob by an average of about 10%.

[0004] The inner and outer edge angles of the disc cutter are offset by α, where: C The outward force applied to the cutter when it is working, F is the rock-breaking force of the rock-breaking cutter.

[0005] The stress distribution of the rock contact area when the disc cutter rolls to break the rock ( Figure 1 ) can be expressed as in, therefore in, σ s is the uniaxial compressive strength of rock.

[0006] Then the rock breaking force F of the disc cutter is, where: is the arc of the rock contact area, r is the radius of the disc cutter, f is the rock breaking friction coefficient, χ is the stress coefficient, B is the cutter blade width, k is the rock yield condition,

[0007] The lateral resistance of the rock-breaking disc cutter to the rock consists of two parts: friction force F m and the resistance of the rock being scraped F g .in The influence on the outer rock is about one third of the cutter spacing. That is, the influence range of the disc cutter on the inner rock is about A'BEF, and the influence range on the outer rock is about A'BGH, as shown in ( Figure 2 ),and Where: SA'BEF——area of ​​annulus A'BEF; Where: SA'BGH——area of ​​ring A'BGH;

[0008] Considering the influence of the rock on the outside of the disc cutter and the balance of the lateral force generated, the area S where the unbalanced rock breaking force actually acts on the inside of the disc cutter is The unbalanced lateral force F acting on the i-th disc cutter on the cutter head is Si for Where: τ—shear strength of rock;

[0009] Therefore, the lateral force F acting on the rock breaking disc cutter is C It can be expressed as The above theory has been verified experimentally.

[0010] ( Figure 3 ) is a schematic diagram of the actual rock-breaking disc cutter and its force-bearing space, ( Figure 4 ) is a plane graph, where F Z F and F C Obviously, the disc cutter of this shape has an outward force F during operation. C , it is easy to break the blade, and even the disc cutter will be stuck and cause string wear, and the rock breaking blade will slide toward the axis of the cutter disc, so the service life is short.

[0011] F and F C Combined into force F Z , and use this force vector to bisect the disc cutter blade angle, as ( Figure 5 ). At this time, the inner and outer edge angles of the disc hob need to be offset, the offset is α, and From this, BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is the stress acting on the rock-breaking edge of the disc cutter;

[0013] Figure 2 This is the effect diagram of the disc cutter breaking rock;

[0014] Figure 3 This is a diagram of the actual rock crushing by the disc cutter;

[0015] Figure 4 It is a disc cutter rock breaking diagram;

[0016] Figure 5 To invent the outline drawing of the disc hob;

[0017] Figure 6 It is the outline diagram of the disc-shaped hob invented in the embodiment; Specific embodiments

[0018] The embodiments of the present invention are described in detail below. The embodiments are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Taking Suchang porphyry as an example, its compressive strength σs=100.57MPa, shear resistance τ=15.65MPa, friction coefficient with disc cutter f=0.032; disc cutter 17″, blade angle φ=20° determined by traditional method, blade width B=16mm, installation radius Ri=742mm on the cutterhead, cutter spacing Ri-Ri-1=70mm; the rated load of the cutter F=250KN. Then or but

[0019] Example disc cutter Figure 6 shown.

Claims

1. A disc cutter for efficient rock breaking, characterized in that: The force vector bisects the disc cutter blade angle, and the inner and outer blade angles of the disc cutter are offset by α, where: In the formula, F C The outward force applied to the cutter when it is working, F is the rock-breaking force of the rock-breaking cutter.

2. The disc cutter for high-efficiency rock breaking according to claim 1, characterized in that: The rock breaking force of the disc cutter In the formula, is the arc of the rock contact area, r is the radius of the disc cutter, f is the rock breaking friction coefficient, χ is the stress coefficient, B is the cutter blade width, and k is the rock yield condition 3. The high-efficiency rock-breaking disc cutter according to claim 2, characterized in that: The stress distribution of the rock contact area in the disc cutter rolling rock breaking (Figure 1) can be expressed as in, therefore In the formula, σs is the uniaxial compressive strength of rock.

4. The high-efficiency rock-breaking disc cutter according to claim 1, characterized in that: The lateral resistance of the rock-breaking disc cutter to the rock consists of two parts: friction force F m and the resistance of the rock being scraped Fg, and In the formula, F Si is the unbalanced lateral force acting on the i-th disc cutter on the cutter head.

5. The high-efficiency rock-breaking disc cutter according to claim 4, characterized in that: The disc cutter is subjected to friction from the rock; 6. The high-efficiency rock-breaking disc cutter according to claim 4, characterized in that: The unbalanced lateral force of the disc cutter acting on the i-th disc cutter on the cutter head is: Where: τ——shear strength of rock, R i is the trajectory circle radius of the i-th hob.

7. The high-efficiency rock-breaking disc cutter according to claim 6, characterized in that: The influence on the outer rock is about one third of the cutter spacing. That is, the influence range of the disc cutter on the inner rock is about A'BEF, and the influence range on the outer rock is about A'BGH, as shown in (Figure 2) and In the formula, SA'BEF is the area of ​​the annulus A'BEF.

8. The high-efficiency rock-breaking disc cutter according to claim 6, characterized in that: Where, SA'BGH is the area of ​​the ring A'BGH.

9. The high-efficiency rock-breaking disc cutter according to claim 6, characterized in that: The inner and outer edge angles of the disc hob need to be offset, and the offset is α, so the inner and outer edge angles of the disc hob are Where φ is the blade angle.

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