Anchor rod

Abstract

The utility model relates to an anchor rod which comprises anchor rod steel, a tray sleeved on the anchor rod steel and a nut in threaded connection with the anchor rod steel, an anti-attrition gasket is arranged between the nut and the tray, the anchor rod steel comprises a cylindrical rod body, an outer ring of the rod body is provided with an external thread, the external thread is a trapezoidal thread, the tooth bottom width of the external thread is 1mm-3mm, and the thread bottom width of the external thread is 1mm-3mm. According to the anchor rod, the thread height of the external threads ranges from 1 mm to 2 mm, the thread pitch of the external threads is two times of the thread bottom width, and compared with an existing conventional anchor rod, the anchor rod has the advantages that the anchoring force and the material utilization rate are greatly improved under the same condition; meanwhile, the anchor rod steel is simple in structure, convenient to machine and manufacture, low in cost and good in surrounding rock reinforcing effect.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of anchor rod, specifically refers to a kind of anchor rod. BACKGROUND

[0002] Resin anchor rod is widely used in good condition coal mine as a traditional supporting material. The anchor rod currently used is mainly of three types: one is a twisted resin anchor rod metal rod body, one is a resin anchor rod without longitudinal rib screw thread steel, and the other is a resin anchor rod with equal strength screw thread steel. The equal strength screw thread steel resin anchor rod is convenient to process, the whole rod body can be screwed with nut, and the length can be freely cut according to the needs. However, the thread pitch of such equal strength screw rod body is relatively large, and the thread pitch is limited by the thread form and pitch, and the thread pitch angle is too large. After the installation of the anchor rod, it is difficult to pre-tighten the nut. At the same time, the cross section of the rod body is similar to an oblong shape, which will squeeze the resin anchoring agent outside the rod body when the rod body rotates and stirs the resin, which is not conducive to the dense bonding of the resin anchoring agent and the rod body, and the anchoring force often cannot reach the best state. SUMMARY

[0003] The utility model provides a kind of anchor rod for the deficiency of prior art.

[0004] The utility model is realized by the following technical scheme, provides a kind of anchor rod, including anchor rod steel, tray that is sleeved on anchor rod steel and nut that is threadedly connected on anchor rod steel, wear-reducing gasket is equipped between the nut and tray, the anchor rod steel includes cylindrical rod body, outer thread is equipped on the rod body, outer thread is trapezoidal thread, the bottom width of outer thread is 1mm~3mm, the height of outer thread is 1mm~2mm, and the pitch of outer thread is 2 times the bottom width.

[0005] As optimization, the middle part of the tray is protruded to the side of the nut. Thus, a cavity is formed on the other side, which facilitates the filling of the anchoring agent.

[0006] As optimization, the pitch of the outer thread is 3.8~6.2mm. It ensures that the anchor rod has a high pre-tightening force after pre-tightening the nut during installation, and improves the torque conversion coefficient during installation of the anchor rod.

[0007] As optimization, the outer thread is provided on the outer circle of the rod body. It is convenient for processing into anchor rod for use, and it can not be limited by the exposed length during installation of the anchor rod, and the anchor rod can be pre-tightened at any time to ensure that the initial pre-tightening force meets the design requirements. After the surrounding rock is broken and unstable, and the surface surrounding rock gangue falls, the anchor rod can be pre-tightened continuously.

[0008] The utility model discloses a beneficial effect is: the utility model discloses a kind of anchor rod, the anchor rod of the utility model is compared with existing conventional anchor rod, under the same condition, it greatly improves anchoring force and the utilization rate of material;After the broken instability of surrounding rock, surface surrounding rock gangue drops, anchor rod can continue to be pre-tightened, while the anchor rod steel structure is simple, processing and manufacturing are convenient, low in cost, and the effect of reinforcing surrounding rock is good. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 It is the sectional view of the anchor rod of the utility model;

[0010] Figure 2 It is the front view of the anchor rod steel of the utility model;

[0011] Figure 3 It is the utility model Figure 1 A portion enlarged view of middle A;

[0012] Figure 4 It is the anchor performance test force-displacement curve diagram of the utility model;

[0013] As shown in the figure:

[0014] 1, anchor rod steel, 2, tray, 3, wear pad ring, 4, nut. DETAILED DESCRIPTION

[0015] To clearly illustrate the technical features of the scheme, the following through specific implementation, the scheme is described.

[0016] As Figures 1 to 4 Shown, the utility model discloses a kind of anchor rod steel, including cylindrical pole body, pole body is made using hot rolling process, material extension rate is high, material utilization is high, simple processing, low in cost.

[0017] Pole body outer circle length is provided with outer thread, pole body thread full length is equal in strength, can not be limited by exposed length when anchor rod is installed, always pre-tightening anchor rod, to guarantee initial pre-tightening force reaches design requirement, outer thread is trapezoidal thread, outer thread can be made as left-handed or right-handed according to demand, the tooth bottom width of the outer thread is 1mm~3mm, the tooth height of outer thread is 1mm~2mm, the pitch of outer thread is 2 times tooth bottom width.The pitch of outer thread in the embodiment is 3.8~6.2mm, guarantees that anchor rod has higher pre-tightening force after pre-tightening nut when installing, improves the moment conversion coefficient when anchor rod is installed.

[0018] A kind of anchor rod, including anchor rod steel 1, tray 2 of being sleeved on anchor rod steel 1 and nut 4 of being threadedly connected on anchor rod steel 1.The wear pad 3 is equipped between the nut 4 and tray 2.The middle of the tray 2 is protruded to nut 4 side.

[0019] In the processing, the anchor rod steel after cutting according to the demand, from bottom to top, nut 4, wear pad 3 and tray 2 are sleeved.

[0020] The anchor rod steel of the utility model is compared with the prior art as follows:

[0021] The anchor rod steel of the utility model selects the nominal diameter of 20mm, the maximum outer diameter of the rod body is 23.9mm, and the thread pitch is 4.1mm.

[0022] The nominal diameter of the anchor rod steel of the prior art is 20mm, the maximum outer diameter of the rod body is 23.9mm, the thread pitch is 12mm, and the thread pitch diameter is 20.95.

[0023] The rod body is compared with the commonly used equal strength rod body thread pitch angle.

[0024] The calculation formula of the thread pitch angle is: Φ = arctan (P / (πD2))

[0025] Wherein, Φ represents the thread pitch angle, P represents the thread pitch, and D2 represents the thread pitch diameter.

[0026] Φ1 = arctan (P / (πD2)) = arctan (4.1 / 3.14 20.9) = 3.5762°

[0027] Φ1 = arctan (P / (πD2)) = arctan (12 / 3.14 20.9) = 10.3648°

[0028] Through comparison, the thread pitch angle of the anchor rod steel rod body of the prior art is much larger than that of the utility model, the resistance of the thread rotation is large, the thread bearing capacity is reduced, and the nut self-locking capacity is not good.

[0029] The anchor rod steel of the utility model is compared with the prior art as follows:

[0030] The experimental purpose is:

[0031] The anchor rod full-length prestressed anchoring support method is an effective means for solving the support of complex and difficult roadways, the shape of the anchor rod is related to the strength coupling and stiffness coupling of the anchor rod and the support body, according to the rock mass properties of the support body, the optimal anchor rod shape (including the pitch, the rod body cross-sectional shape) is selected, the support difficulty of the complex and difficult roadway is solved, and the economic benefits are maximized. The relationship between the anchor rod shape and the anchoring performance of the resin anchoring agent is studied by using the laboratory experiment method, the relationship between the pulling force and the displacement of different anchor rod shapes is obtained, and the optimal anchor rod shape support method is selected according to different mine rock mass environments.

[0032] The experimental method is:

[0033] The anchoring performance experiment mainly studies the bonding performance between different shaped anchor rods and anchoring agents. In this experiment, two anchor rods with different specifications and shapes were anchored in a steel pipe with a height of 300 mm and an inner diameter of 28 mm. The steel pipe provided lateral restraint to ensure that the cementitious body did not displace laterally.

[0034] The anchoring performance test was conducted on a (WAW-1000) type electro-hydraulic servo universal testing machine. The maximum experimental force of the testing machine was 1000 kN, and hydraulic clamping and servo control were used for the tensile and compressive tests of the test piece. The test can achieve continuous full-range measurement and recording. The displacement control was used in the test process, and the loading speed was 5 mm / min. The anchor rod pulling force device is shown in Figure 2 , which is composed of a 100 mm diameter pipe and two fixed caps. The lower part is connected with a 30 mm cylinder to provide pulling force, and the upper part is a fixed cap with an opening aperture of 30 mm. The upper screw cap is opened during the experiment.

[0035] Two types of anchor rods were used in this experiment, and the anchor rod shape parameters are shown in Table 1 below:

[0036] Table 1: Anchor rod shape parameters used in the experiment

[0037]

[0038] Installation process:

[0039] CKb2850 type resin anchoring agent was selected for steel pipe anchoring. The anchoring agent was installed according to the normal mixing and gelation sequence. The pulling anchoring force was measured 2 hours after installation was completed.

[0040] The anchoring force data of the two types of rods were obtained. The force-displacement curve of the anchoring performance test is shown in Figure 4 .

[0041] From the curve, the anchoring performance parameters of the anchor rod sample force-displacement value are obtained:

[0042] Test piece 1 (pitch 12) maximum pulling force 136 KN, extension displacement 12.4 mm;

[0043] Test piece 2 (pitch 12) maximum pulling force 142 KN, extension displacement 14.5 mm;

[0044] Test piece 3 (pitch 4) maximum pulling force 173 KN, extension displacement 14.4 mm;

[0045] Test piece 4 (pitch 4) maximum pulling force 169 KN, extension displacement 13.5 mm;

[0046] Through the analysis of the force-displacement data curve:

[0047] Under the same test condition, the anchoring force is greatly influenced by the shape of the rod body (including the cross-sectional shape, the screw pitch, etc.). The anchor rod steel and the anchor rod made of the anchor rod steel have a significantly larger drawing force.

[0048] Of course, the above description is not limited to the above examples, and the technical features not described in the utility model can be realized by or using the prior art, which will not be described here. The above examples and drawings are only used to illustrate the technical scheme of the utility model and are not a limitation on the utility model. The preferred embodiments of the utility model are described in detail, and those skilled in the art should understand that changes, modifications, additions or replacements made by those skilled in the art within the essential scope of the utility model do not deviate from the purpose of the utility model and should also belong to the protection scope of the claims of the utility model.

Claims

1. An anchor rod, characterized by: The anchor rod steel (1), the tray (2) sleeved on the anchor rod steel (1), and the nut (4) threaded on the anchor rod steel (1), a wear-reducing gasket (3) is arranged between the nut (4) and the tray (2), the anchor rod steel (1) comprises a cylindrical rod body, an outer thread is arranged on the outer circle of the rod body, the outer thread is a trapezoidal thread, the tooth bottom width of the outer thread is 1mm-3mm, the tooth height of the outer thread is 1mm-2mm, and the pitch of the outer thread is 2 times the tooth bottom width.

2. An anchor rod as claimed in claim 1, characterised in that: The middle part of the tray (2) is protruded to one side of the nut (4).

3. An anchor rod as claimed in claim 1, characterised in that: The pitch of the outer thread is 3.8-6.2mm.

4. An anchor rod as claimed in claim 1, characterised in that: The outer thread is arranged on the outer circle of the rod body.

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