Common knowledge in mechanical fundamentals
1. Daily protection and maintenance of machines and equipment is of utmost importance. Regardless of whether the machines and equipment are new or old, the principle of "protection as the primary focus and maintenance as a secondary measure" should be followed.
2. Belt drives can be divided into V-belt drives, flat belt drives and round belt drives. The vacuum pump used in our factory's pressure swing adsorption system is a V-belt drive.
3. In belt drive systems, there are usually tensioning devices to adjust the tension.
4. When installing pulleys, the center lines of the two pulleys must be parallel to ensure that the pulleys are not misaligned or runaway on the axis.
5. The primary failure modes of belt drives are slippage and fatigue damage.
6. The effects of gear backlash: First, it prevents gear teeth from jamming due to errors and thermal deformation in the gear pair. Second, it provides space for the lubrication surfaces between the gear teeth.
7. Common gear failure modes are mainly manifested in five categories: wear, scuffing, surface fatigue, plastic deformation, and fracture.
8. Depending on the different operational requirements of the parts, the cooperation can be divided into three categories: clearance cooperation, interference cooperation, and transition cooperation.
9. Mechanical seal failures manifest during operation as vibration, heat generation, and wear, ultimately resulting in media leakage.
10. The three primary parameters that indicate the performance of a pump are: flow rate, pressure, and power.
11. The head of a centrifugal pump decreases as the flow rate increases.
12. For centrifugal pumps, axial seals can be either packing seals or mechanical seals.
13. Rolling bearings consist of four parts: inner ring, outer ring, rolling elements, and cage.
14. Ordinary rolling bearings are represented by four numbers.
15. The function of a check valve is to restrict the direction of fluid flow and prevent the liquid from flowing in the opposite direction.
16. The standard saw blade length for fitters is 300mm.
17. The method of indicating pipe thread is as follows: G3/4 indicates its inner diameter.
18. In the steel wire rope 6×37+1, 6 refers to the number of strands, 37 refers to the number of steel wires in each strand, and 1 refers to the presence of an oil-immersed core in the center.
19. For welding 1Cr18Ni9Ti stainless steel to stainless steel, the welding rod type A132 is required. For welding stainless steel to carbon steel, the commonly used welding rod type A302 is required.
20. Steel pipes can be divided into two main categories: welded steel pipes and seamless steel pipes.
21. The standard for seamless steel pipes and welded steel pipes is usually expressed as outer diameter × wall thickness.
22. There are two types of welding machines: AC welding machines and DC welding machines.
23. 1000 micrometers equals 1 millimeter, and 1 millimeter equals 100 filaments.
24. The braided length of the wire rope knot used must be greater than 15 times the diameter of the rope and not less than 300 mm.
25. The removal and installation of blind flanges must be carried out in accordance with the blind flange management regulations. The thickness of the blind flange must be greater than the thickness of the pipe wall, and a handle must be provided.
Dynamic balancing principle experimental platform
I. Overview of Dynamic Balancing Principle Experimental Platform, Mechanical Fundamentals Experimental Platform, and Dynamic Balancing Experimental Equipment
The rotor assembly of the dynamic balancing principle experimental platform rests on supporting rollers on a frame-shaped pendulum. The pendulum is rigidly supported at the left end, while the right end features a suspended device. Through dynamic balancing experiments with a rigid rotor, students can intuitively and deeply understand the principles of dynamic balancing and the real-time conditions of each eccentric wheel during the laboratory process (eccentricity angle, mass-to-diameter product, rotational speed, etc.). Examples include: the influence of unbalanced mass on dynamic balance, the influence of the unbalanced mass's position relative to the rotor center on dynamic balance, and the influence of the angle between the two eccentric masses on dynamic balance.
II. Primary Technical Parameters
1. Motor power: 90W
2. Operating voltage: 220V
3. Motor speed range: 0-1400 rpm;
4. Dial indicator range: 0-10mm
5. Dynamic balancing speed: 450 rpm
6. Specimen weight: ≤10kg
7. Maximum specimen diameter: Φ=200mm
III. Experiment Content
1. The effect of unbalanced mass on dynamic balance;
2. The effect of changes in the relative phase angle of each unbalanced mass on dynamic balance;
3. A method for calculating the product of the unbalanced mass on the rotor under test and the compensating mass on the compensating disc to achieve dynamic balance.
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