The roughness of the friction surface of the friction pair test piece is Ra3. 2μm, and its technical parameters are as follows. The test prototype is WD-150 Archimedes worm gear reducer, its main technical parameters: center distance a=150mm; number of teeth z1=1, z2=37; modulus m=6mm; worm diameter coefficient q=11; pressure angle α=20°; displacement coefficient x2=1. 0; helix angle λ=5.195°; gear ratio i=37. For the material, heat treatment and hardness of the worm gear pair, the roughness of the tooth surface is Ra3. 2μm.
Table 1 Main technical parameters of worm gear transmission and friction pair Material heat treatment hardness (HBS) steel worm gear transmission worm (test ring) 45 steel tempering 265 (steel steel friction pair) worm gear (test block) 45 steel tempering 240 copper worm Auxiliary drive worm (test ring) 45 steel quenching and tempering 265 (steel-copper friction pair) worm gear (test block) ZCuSn5Pb5Zn5170 before the test of the steel worm gear reducer tooth surface running. Clean the worm reducer and load an appropriate amount of running oil. The DC speed-regulating motor is used to gradually increase the input speed from low speed to rated speed under light load. When the rated speed and load are basically stable, the load is increased by one step. In this way, the load is added to the rated value for running. After the running, the tooth surface roughness also improves the tooth surface contact accuracy and the tooth surface hardness before running.
The test oil and the content steel friction pair are continuously lubricated with GL-5 extreme pressure gear oil, and the steel copper friction pair is continuously lubricated with L-CKE ordinary worm gear oil. Under the same working conditions, the friction and wear properties of each pair of friction pairs were tested on the MHK-500 TIMKEN test machine. The spindle speed of the test machine was n=1500r/min. The test ring was connected to the test machine spindle. Connected to the deck underneath, the test ring rotates and the test block is tightened. Loaded and tested by the load bar and weight of the lever system, each running time is 10min.
The steel worm drive is lubricated with GL-5 extreme pressure gear oil, and the copper worm drive is lubricated with L-CKE common worm gear oil. On the worm and worm test bench, each worm drive is operated under 100 rated load. After reaching the thermal balance, the transmission efficiency of each drive and the temperature rise of the lubricating oil are tested respectively. The input speed is n1=1450r/min, and the rated output turns. Moment [5] T2 = 347 Nm. In order to improve the accuracy of the test data and the reproducibility of the test results, each test data herein is an average of three reproduction test data.
The test results and analysis of the friction coefficient test results of the two pairs of friction pairs are listed, it can be seen that the friction coefficient of the steel friction pair is smaller than the friction coefficient of the steel copper friction pair, and the friction factor of each friction pair is not affected by the load change.
Fig. 2 Friction coefficient curve The test results of the wear of the two pairs of friction pairs are listed. It can be seen that the wear scar area of ​​the steel friction pair is smaller than the wear scar area of ​​the steel copper friction pair, and the wear amount of each friction pair increases with the increase of the load. The friction and wear characteristics appear directly in the worm drive are the transmission efficiency, the temperature rise of the lubricating oil and the bearing capacity.
Fig. 3 Wear amount (wear scar area) curve The two worm gear drives are operated under 100 rated load respectively. After reaching the heat balance, the transmission efficiency and the temperature rise of the lubricating oil are listed. It can be seen that the transmission efficiency of the steel worm drive is higher than that of the copper worm drive, and the temperature rise of the lubricating oil is lower than that of the copper worm drive. Finally, the maximum load carrying capacity of the two worm drives is tested separately. The result is that the bearing capacity of the steel worm drive is higher than that of the copper worm drive.
Table 2 Maximum loading rate () and temperature rise (°C) test results Lubricating oil temperature rise Maximum loading rate Steel worm gear drive 51160 copper worm gear drive 58120 Through test and analysis, the transmission performance of steel worm gear drive is better than copper Transmission performance of the worm gear drive. The key problem of steel worm gear transmission is how to prevent the tooth surface glue, which is also the root cause of the difficult realization of steel worm gear transmission. Since the steel reinforced material composed of the steel worm wheel and the steel worm has strong mutual solubility, once the lubricating film between the friction surfaces breaks during work, the surface metal directly contacts, and it is easy to cause adhesion or even gluing.
Transmission efficiency curve The extreme pressure agent in the GL-5 extreme pressure gear oil of this paper is a sulfur-based extreme pressure additive. Its extreme pressure must produce a good friction extreme pressure chemical reaction in the presence of air (oxygen). Temperature), or tribochemical adsorption (lower temperature). Namely: in the presence of iron oxide-iron sulfide film (Fe3O4-FeS), there is better lubrication. The iron oxide film acts as a catalyst, and only under the Fe3O4 film, the iron on the friction surface can be vulcanized by the active sulfur atom dissociated by the sulfide, and a tribochemical reaction occurs to form a soft, high melting point chemical lubrication with small shear strength. Membrane - iron sulfide (FeS). The sulfur-based extreme pressure additive adsorbs on the surface of the metal (Fe) at a polar end at a low temperature to form a chemical adsorption film. The SS bond and the CS bond are present in the molecule of the sulfur-based extreme pressure additive, and the SS bond is a weak bond with a lower bond energy. Under normal working conditions, the SS bond is first broken to form an iron-thiol film, and the film has better Anti-wear effect. Under extreme pressure, the CS bond is broken to form an iron sulfide film (FeS). The film has high load carrying capacity and high melting point. When the temperature is close to 800 °C, it can maintain good lubricating properties and its hydrolysis performance is also good. . The organosulfide chemically reacts with the metal (Fe) only at high temperatures (greater than 200 ° C). Therefore, under extreme pressure conditions, in general, the lubricating effect of the sulfur-containing additive is better than that of the chlorine-containing or phosphorus-containing additive. Its molecular structure is: θCH2-SS-CH2θ. The reaction mechanism of this extreme pressure agent is: when the temperature is low, the molecules of the extreme pressure agent are adsorbed on the surface of the metal (Fe) to form a chemical adsorption film; when the temperature reaches a certain temperature At the time of the value, the SS bond in the extreme pressure agent molecule is broken, and the dibenzyl disulfide forms only the oily iron thiol film; at high temperature, the CS bond in the molecule is broken, and all of the polar iron sulfide is formed. membrane. The reaction film softens the convex portion of the metal surface and reduces the resistance at the time of collision. At the same time, due to the plastic deformation to fill the pits on the metal surface, the contact area is increased, the unit load on the contact surface is reduced, and the friction and wear are reduced. Extreme pressure reaction membranes have high strength and can withstand large loads, which can reduce wear and prevent gluing [3].
Normal single head CNC Router Machine, size 1325, 1530, 2030, 2040 etc, and customized size also provided. with 3kw spindle, 4.5kw, 5.5kw, 6kw etc, china brand or Italy hsd.
Machine samples:
Package:
1. Outside package: Standard marine export plywood case.
2. Inner package: Stretchy film and plastic film for humidity.
Standard 3 Axis CNC,3 Axis CNC Router,3 Axis CNC,3 Axis CNC Machine
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