Primary level
fill (up) a vacancy
1. The hydraulic oil pump is the (power) mechanism in the hydraulic transmission system.
2. Gray cast iron is represented by symbol (HT), nodular cast iron by symbol (QT) and malleable cast iron by symbol (KT).
3. The tooth profile angle of ordinary standard cylindrical gear is (20).
4. When the belt is driven, if the tension is not enough, the belt will easily slip under the load; If the tension is too large, the life of the belt will be greatly shortened.
5. Heat fit is suitable for (interference) fit.
6. If the coaxiality of the spindle journal exceeds the allowable tolerance, it will cause the spindle to run off in rotation.
7. The research point of the national first-class flat panel should be within 25mmX25mm (20 -25).
8. Artificial correction includes (torsion), (bending), (stretching) and (elongation).
9. The choice of file thickness depends on the workpiece (machining allowance), (machining accuracy), (surface roughness) and (material properties).
10. To correct the convex piece in the middle, it is necessary to hammer (edge) first, from (outside) to (inside) and from heavy to light, from dense to sparse, and gradually flatten the convex part.
1 1. Spiral transmission can transform the (rotary) motion of the driving part into the (linear reciprocating) motion of the driven part.
12. The types of chain drive are (transmission) chain drive, (lifting) chain drive and (traction) chain drive.
13. Cutting fluid has the functions of (cooling), (lubricating) and (cleaning).
14. When assembling ordinary wedge keys, make the keys (upper and lower working faces) stick to the bottom of shaft grooves and hub grooves with gaps (both sides).
15. Cutting movement is the relative movement of (tool) and (workpiece) contacting each other to remove excess metal.
16. The cutting edges of the drill are symmetrically distributed (axisymmetrical), and the radial cutting forces cancel each other, so the drill is not easy to bend.
17. In planing, (linear reciprocating) motion is the main motion.
18. In order to ensure that the rolling bearing has a certain thermal expansion space when working, the inner ring or outer ring of one of the two coaxial bearings must be able to move (axially) during thermal expansion.
19. The accuracy of the shaft mainly includes (dimensional accuracy), (geometric accuracy), (mutual position accuracy) and (surface roughness).
20. When assembling the worm drive mechanism, the axial position of the worm wheel can be adjusted by changing the thickness of the washer.
2 1.(HT/K6) The fit between pulley hole and shaft usually adopts interference fit.
22. For the rigid rotor with low rotation speed, its unbalanced state can be divided into two types, namely, (static) imbalance and (dynamic) imbalance.
23. Apply proper pressure when sawing, the reciprocating stroke should be short, and the sawing angle should be slightly less than (15).
24. The fixed sleeve of the micrometer is engraved with scribed lines with a spacing of 0.5mm, and 50 grids are evenly engraved on the circumference of the differential cylinder. Therefore, every time the differential cylinder rotates one grid, the micrometer screw moves in (0.0 1mm).
25. Tempering can be divided into (low temperature) tempering, (medium temperature) tempering and (high temperature) tempering.
26. In order to ensure the correct meshing of each pair of involute gears, it is necessary to ensure that their (modulus) and (tooth profile angle) are equal respectively.
27. The assembly methods of rolling bearings are: knock-in method, (press-in) method and (temperature difference) method.
28.GCr 15 is bearing steel, g is bearing steel, and 15 is chromium content 1.5%.
29. Three views include (main) view, (prone) view and (sitting) view.
The damage of mechanical parts can be divided into two ways: (natural wear) and (accidental wear).
Two. multiple-choice
1. If the measured angle is greater than 90 and less than180, add a (a) when reading.
180
2. On the vernier of 0.02mm vernier caliper, the 50th grid line is aligned with the (a) mm grid line on the scale.
A. 19
3. There is a hole with a size of Φ 200+0.33 mm to fit the shaft with a size of Φ 200+0.33 mm, and the maximum clearance should be (b) mm. ..
A.0.066 B.0.033 C.0 0.044
4. When installing the V-shaped pulley, the radial circular runout is required to be (a) times the diameter of the pulley.
a . 0.0025-0.0005 b . 0.025-0.005 c . 0.25-0.5d . 2.5-5
5. In hydraulic transmission, use (b) to change the movement speed of the piston.
A. reversing valve B. throttle valve C. overflow valve D. safety valve
6. The tool rake angle, rake angle and the sum of the wedge angle (c).
A. greater than 90 b. less than 90 c. equal to 90 d.0
7.(C) Suitable for transmission between two parallel shafts.
A. bevel gear B. worm and worm wheel C. cylindrical gear D. spiral gear
8. The method of correcting the lead screw with a press belongs to method (c).
A. Stretching, twisting, bending and extension
9. When the hole to be processed needs to be drilled, expanded and reamed in turn, (c) should be used.
A. fixed drill sleeve B. replaceable drill sleeve C. quick-change drill sleeve D. special drill sleeve
10. The long drive screw and polished rod removed from the machine tool should be (d) to avoid deformation.
A. use a v-shaped frame to horizontally support both ends. B. free and sustainable resettlement. C. inclined placement. D. vertical suspension
1 1. chisel, chisel back angle is generally (b).
A.3—5b . 5—8c . 8— 10d . 10— 12
12. The vertex angle 2 φ of the standard twist drill is (b).
A. 1 10φ2b 1 18 2c 125 2d 130 2
13. When sawing hard materials, pipes or sheets, the saw blade (c) should be used.
A. coarse teeth B. middle teeth C. fine teeth D. taper
14. The tool material with good heat resistance and cutting temperature of 540℃-620℃ is (B).
A. cemented carbide B. high speed steel C. alloy tool steel D. carbon tool steel
15. Among the following four steels, (a) has the highest hardness.
A.T 10 steel B.20 steel C.65Mn steel D.A3 steel
16. Tempering treatment is the heat treatment of (c).
A. quenching+low temperature tempering B. quenching+medium temperature tempering C. quenching+high temperature tempering D. quenching
17. When making ruler teeth with 40Cr steel, the typical heat treatment process after forging is (b).
A. normalizing B. complete annealing C. tempering D. tempering
18. In order to improve the surface hardness and wear resistance of gray cast iron, the heat treatment method of (b) is better.
A. quenching, heating and tempering after carburizing B. electric contact heating surface quenching
C. Isothermal quenching D. High temperature tempering
19.P 10 cemented carbide tools are often used for cutting (a).
A. common steel B. heat-resistant steel C. cast iron D. alloy steel
20. In the tensile test, the maximum stress that the sample can bear before fracture is called (B) of the material.
A. yield point B. tensile strength C. elastic limit D. impact toughness
The better (b) of 2 1. material, the better its fracture.
A. strength b plasticity c hardness d toughness
22. When scribing, the line used to determine the size, geometry and relative position of each part of the workpiece is called line (C).
A. Original B. Zero C. Datum D. Center
23. When marking the surface of castings and forgings, (c) coating can be used.
A. Pinzi B. Copper sulfate solution C. Lime water D. Hong Tong powder
24. When gouging, the included angle between the rake face and the base face before gouging is (B).
A. Wedge angle B. Front angle C. Back angle D. Edge angle
25. The main working face of the file refers to the file tooth (A).
A. upper and lower sides B. both sides C. upper and lower sides D. all surfaces
26. The nominal diameter of thread refers to the basic size of thread diameter, namely (A).
A. external thread crest diameter or internal thread root diameter
B. Diameter of root of external thread or top of internal thread
C. crest diameter of internal and external threads
D. Diameter of internal and external thread roots
27. Mainly used in carbon tool steel, alloy tool steel, high speed steel and cast iron abrasive is (B).
A. carbide abrasive B. oxide abrasive C. diamond abrasive D. others
28. Static imbalance is characterized by always staying in the vertical direction (B).
A. Same position B. Lowest position C. Highest position D. Different positions
29. The lathe spindle drives the relative movement of the tool and workpiece to complete the cutting work (A).
A. main movement B. feed movement C. auxiliary movement D. electric feed
30. The straightness tolerance of the bed guide rail of the horizontal lathe slide plate in the vertical plane is 0.02mm per meter, and it is (B) in the whole stroke.
A. only concave B. only convex C. it can be concave or convex.
D. it can be concave or convex.
3 1.CA6 140 Radial circular runout and axial running response of spindle of horizontal lathe (C).
A. not more than 0.0 1 mm b. Not less than 0.03mm.
C the diameter is between 0.02 mm and 0.03 mm. The diameter is between 0.0 1 mm and 0.02 mm.
32.Z525 electric drill gearbox can get nine different speeds. The speed change is realized by changing the engagement of (b) sliding gears installed on two spline shafts.
A. two sets of two links B. two sets of three links C. three sets of three links D. three sets of four links
33. In the assembly method, the repair method is applicable to (a).
A. Single production B. Mass production C. Quantitative production D. Mass production
34. The mechanical locking device has (a) locking device.
A. Stop washer B. Spring washer C. Lock nut D. Countersunk nut
35. Bearing type (C) bears both radial and axial forces.
A. radial bearing B. thrust bearing C. radial thrust bearing D. needle bearing
36. Model 2000 rolling bearing has a diameter of (A) mm. ..
10
37. You can use (a) to remove the cylindrical hole bearing.
A. Press or tensioner B. Hammer C. Knock in D. Temperature difference method
38. The operation process of connecting parts, assemblies and parts into a complete machine is called (C).
A. Component assembly B. Component assembly C. General assembly D. Integral assembly
39. After the reducer worm shaft assembly is loaded into the box, the axial clearance between the shaft end and the bearing cover should be (A).
A. 0.0 1 mm ~ 0.02 mm b. 0. 1 mm ~ 0.2 mm c. 1 mm ~ 2 mm d. 0.2 mm ~ 0.3 m.
40. In the chain drive, the teeth of the sprocket are gradually worn, and the tooth pitch is increased, which accelerates the wear of the chain. When the wear is serious, it should be (c).
A. adjust the center distance of the sprocket B. replace a single link C. replace the chain and sprocket D. replace the sprocket
4 1.(b) can improve the hardness of metal parts.
A. annealing B. quenching C. tempering D. normalizing
42. After reaming, exit the reamer position should be (b).
A. reverse rotation B. forward rotation C. non-rotation D. hammering
43. Cleaning the equipment, partially disassembling parts or partially replacing worn parts, and adjusting the fastening mechanism to ensure that the equipment can meet the production process requirements belongs to (c).
A. Overhaul B. Medium repair C. Minor repair D. Fixed repair
44. The metric standard triangular thread tooth angle is (A).
A.60 B.55 C.40 D.30
45. When repairing the horizontal lathe, if the height of the center line of the spindle taper hole and the center line of the tailstock top taper hole is not satisfied, use (c) to make it meet the requirements.
A. Matching method B. Adjustment method C. Repair method D. Assembly method
46. To make the mechanical transmission mechanism compact, accurate and short-distance transmission, you can choose (A) transmission.
A. gear B. belt C. chain D. screw
47. When filing, if the torque produced by endurance is unbalanced, the surface of the workpiece will be pressed into a (B).
A. plane B. arc convex surface C. arc concave surface D. curved surface
48. When the box is connected internally, it is usually locked by (A).
A. lock nut B. spring washer C. series steel wire D. stop washer
49. Mechanical pressure, slow action, low precision requirements, (A) lubricating oil should be used.
A. high viscosity B. low viscosity C. high evaporation point D. low evaporation point
50. The stud assembly, its axis must be consistent with the body surface (C).
A. coaxial lines B. parallel C. vertical D. staggered
judge
1. On the shaper, the reciprocating linear motion of the shaper becomes the main motion. (√)
2. The file thickness * * * is divided into No.5, 1# is the thickest, and No.5 is the thinnest. (√)
3. When reaming cast iron holes, adding kerosene lubrication will reduce the hole diameter after reaming. (√)
4. When installing slips, pay attention not only to the direction of tooth tip, but also to the tightness. (√)
5. When scraping the original flat plate, four flat plates should be scraped together. (10)
6. When bending, the neutral layer is generally not in the middle of the material, but to the side of the inner layer material. (√)
7. The national standard stipulates that the base hole should be combined with the base shaft system. Generally speaking, the base shaft system should be preferred. (10)
8. Universal angle ruler can measure any angle from 0 to 360. (×)
9. When the circumference is divided into equal parts according to the same chord length, the more equal parts, the smaller the product error. (10)
10. When drilling, the main purpose of cooling and lubrication is lubrication. (×)
1 1. When checking the shape error, the variation of the measured actual component relative to its ideal component is the shape tolerance. (10)
12. A common step usually includes one or several working procedures. (×)
13. When assembling, the cleaning of parts is a very important job. Rubber products (such as sealing ring parts) must be cleaned with gasoline. (×)
14. Before assembly, the rolling bearing must be cleaned with a brush and cotton yarn. Only in this way can they be cleaned. (×)
15. The function of static balance is to eliminate the bias of parts at any position and make the center of gravity of rotating parts coincide with the center of rotation. (√)
16. Double nut locking and locking device belongs to mechanical locking device. (×)
17. Loose welding alignment is better than tight welding alignment. (√)
18. When installing the V-belt, first put the V-belt into the groove of the big pulley, and then put it on the small pulley. (×)
19. Chain transmission mechanism is suitable for transmission between two shafts with close distance. (×)
20. In gear transmission, backlash is not a precision index, but different backlash should be determined according to different working conditions of gears. (√)
2 1. In the assembly of parts, supplementary processing mainly refers to the mechanical processing of parts in the assembly process. (√)
22. When the assembly accuracy is very high in mass production and the number of component rings is small, the selective assembly method is a common method to realize the assembly accuracy. (√)
23. Mechanical equipment shall be disassembled in the same order as when assembled. (×)
24. The daily inspection of equipment is to find abnormal phenomena in time and eliminate them. (√)
25. The brand of lubricating oil is expressed by numbers. The higher the number, the higher the viscosity. (√)
26. The connection of interference fit parts should generally not be disassembled and reassembled after assembly. (√)
27. The smaller the pitch of the thread, the higher the accuracy of the thread. (×)
28. All materials can be straightened and bent. (×)
29. When the integral sliding bearing is damaged, the method of repair is generally adopted. (×)
30. The purpose of thread locking is to prevent the friction torque from decreasing and the nut from turning. (√)
3 1. When the ordinary wedge key is connected, the upper and lower sides of the key are working faces, and there is a certain gap between the key side and the keyway. (√)
32. When assembling the key, check the contact between the two sides of the key and the shaft groove and hub groove by coloring method. (×)
33. When using a vise for strong operation, try to make the force toward the movable pliers body. (×)
34. When marking a large number of identical workpieces, duplicate marking can be used. (×)
35. For reaming on cast iron, kerosene can be used as cutting fluid to improve surface roughness. (√)
36. The corrected part of the tap has a complete tooth profile and the cutting part has a taper angle. (√)
37. The dimensional tolerance of parts can be positive, negative and zero. (×)
38. In the assembly dimension chain, the final ring is the component ring. (×)
39. The original clearance of rolling bearing is greater than the fit clearance, and in general, the fit clearance is greater than the working clearance. (×)
40. When there are two holes on one side of the workpiece, one hole is positioned with a cylindrical pin and the other hole is positioned with a conical pin. (×)
Four. Short answer
1. What basic operations must the fitter master?
Answer: The fitter must master the basic operations such as marking, chiseling, sawing, filing, drilling, reaming, countersinking, reaming, tapping and tapping, correcting and bending, riveting, scraping, grinding, assembly and debugging, measuring and simple heat treatment.
2. When sawing, why should the saw blade have a sawing path?
Answer: After the saw blade has a saw path, the width of the saw seam on the workpiece is greater than the thickness of the back of the saw blade, which can prevent the saw blade from being "stuck" or overheated and reduce the wear of the saw blade.
3. Why can't the reamer be reversed when reaming?
Answer: Reverse rotation will make the chips roll between the hole wall and the flank of reamer teeth, which will make the hole wall rough. In addition, reverse rotation is easy to wear and even collapse the reamer. Therefore, the reamer cannot be reversed when reaming.
4. Why must the diameter of bottom hole be larger than the basic size of thread diameter before tapping?
Answer: If the diameter of the bottom hole is equal to the diameter of the threaded hole, there will not be enough gap between the thread crest and the root of the tap due to extrusion during tapping, and the tap will easily get stuck, making it difficult to continue tapping, or even the tap will break. Therefore, the diameter of the bottom hole before tapping must be larger than the basic size of the thread diameter.
5. What are the characteristics of maintenance assembly?
Answer: (1) reduces the machining accuracy requirements of parts.
(2) No high-precision processing equipment is needed, and the processing time is saved.
(3) The assembly work is complicated and the assembly time is increased, which is suitable for single piece, small batch production or mass production of high-precision products.
6. What are the assembly methods of interference connection?
Answer: Press fit method, thermal expansion fit method, cold shrinkage fit method, hydraulic sleeve method and explosive pressing method.
7. What are the similarities and differences between couplings and clutches?
A: Similarities: Coupling and clutch are usually used to connect two shafts to make them rotate together and transmit torque. Difference: the coupling can only be separated from the two shafts by disassembly when the machine stops running; When the machine is running, the clutch can be engaged and disengaged at any time through the operating system.
8. What are the characteristics of sliding bearings?
Answer: The operation is reliable, the transmission is stable, and there is no noise. The lubricating oil film has the ability to absorb vibration and can bear a large impact load.
9. What is the clearance of the rolling bearing?
Answer: The maximum movement of a rolling bearing in radial and axial directions is called the clearance of the rolling shaft.
10. What is the reason for the error when the gear is installed on the shaft?
Answer: There are eccentric and helical gears, and the section is not close to the shaft shoulder.
1 1. What auxiliary measures can be taken when the thread is rusty and difficult to disassemble?
Answer: spray special thread loosening agent or soak it in kerosene; Knock on the door; Heat the nut with flame.
12. What are the four parts of the product assembly process?
A: preparation before installation; Assembly; Adjustment, precision inspection and trial operation; Painting, oiling and packaging.
13. What are the methods to control the pre-tightening force during thread assembly?
Answer: Control with special assembly tools; Measuring the elongation of bolts; Torsion angle method control.
14. What is the reason for the noise generated by the machine?
A: Fluid impact; Friction between objects; Mechanical vibration.
15. What are the functions of grinding?
Answer: reduce the surface roughness; Meet the precise size requirements; ; Improve the geometric shape of the workpiece.
16. What are the types of scraping?
A: Scraping can be divided into plane scraping and curved surface scraping.
17. What are the common damage forms of belt drive mechanism?
Answer: The common damage forms of belt transmission mechanism are journal bending, loose fit between pulley hole and shaft, pulley groove wear, belt elongation or fracture and wear.
18. What is the main reason for tool wear?
A: There are three main reasons for tool wear: mechanical wear, phase change wear and chemical wear.
19. What is the purpose of the balance test of rotating parts?
Answer: mainly to prevent the unbalanced centrifugal force when the machine works; Eliminate the vibration caused by the unbalanced movement of parts, ensure the accuracy of the machine and prolong the service life.
20. What are the technical requirements for assembling the screw mechanism?
Answer: The assembly of the lead screw mechanism has the following technical requirements: 1, reasonable fit clearance, flexible rotation of the lead screw nut and excessive coaxiality error of the lead screw nut.
2 1. What is the main function of the assembly unit system diagram?
Answer: 1 clearly reflects the assembly process, part name, number and quantity of the product. 2. The assembly process can be divided according to the assembly unit system diagram.
22. What are the basic requirements for the material of the cutting part of the tool? What are the commonly used tool materials?
A: Cutting some materials with a tool has the following requirements: high hardness; Sufficient strength and toughness; High wear resistance; High heat resistance; Good thermal conductivity; Good process performance, etc. Tool materials commonly used by locksmiths are carbon tool steel, alloy tool steel, high speed steel and cemented carbide.
23. What is dynamic imbalance?
Answer: The rotating parts are offset (or offset each other) in radial position, and the two offsets are separated by a certain distance in axial position, resulting in rotational imbalance, which is called dynamic imbalance.
24. What is the level of screw rotation accuracy?
Answer: The accuracy of screw rotation is mainly manifested in the radial circular jump and axial movement of the screw.
25. What is an assembly dimension chain? What are its characteristics?
Answer: The so-called assembly dimension chain refers to the general term of interrelated dimensions. The assembly dimension chain has two characteristics: 1, and all related dimensions are connected into a closed shape. 2. Every independent dimensional error that constitutes this closed shape will affect the assembly accuracy.
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