Fill in the blanks:

1, the main performance parameters of hydraulic pump are flow, volumetric efficiency, pressure, power, mechanical efficiency and total efficiency. 2. There are many kinds of hydraulic pumps, such as gear pumps, vane pumps, piston pumps and screw pumps. 3. Hydraulic control valves can be divided into three categories: directional control valves, pressure control valves and flow control valves. 4. The pressure control valve is used to control and adjust the working pressure in the hydraulic system to obtain the force or torque required by the actuator. 5. The pressure control valve includes safety valve, pressure reducing valve and sequence valve. 6. The flow control valve is used to control and adjust the flow of oil passing through the valve port, so that the actuator can generate corresponding movement speed. 7. The flow control valve includes throttle valve and speed regulating valve. 8. The function of one-way valve is to make the oil flow only in one direction. 9. The function of the directional control valve is to control the oil flow direction in the hydraulic system, thus changing the movement direction or working sequence of the actuator. 10. The reversing valve uses the relative movement between the valve core and the valve body to change the direction of oil flow and connect or close the oil circuit.

The legal length marked on mechanical manufacturing drawings is millimeters, and the conversion relationship between legal length and English system is 1 inch =25.4 millimeters.

Derusting methods include mechanical derusting, chemical derusting and electrochemical derusting.

Key connection is divided into loose key connection, tight key connection and spline connection.

Rolling bearings are divided into centripetal type and thrust type according to the direction and size of load.

The errors of measurement methods include systematic errors and random errors.

Commonly used disassembly methods include knocking unloading method, drawing method, jacking method and temperature difference destruction method.

The main file pattern on the working face of the file is the main file pattern.

When riveting, the diameter of the rivet is related to the thickness of the connecting plate.

The height (or length) of a spring without external force is called the free height (or length).

The main purpose of adding cutting fluid during drilling is cooling.

The tap consists of a working part and a taper handle.

Cutting angle of saw blade: rake angle and rake angle.

Coupling is divided into rigid coupling and flexible coupling.

Compared with adjustable wrench, it is safer to use the dummy wrench, and it is more convenient to use the dummy wrench in adjustable wrench.

The first-level maintenance of equipment is carried out by the operator, who is responsible for the daily lubrication and maintenance of equipment. The secondary maintenance of equipment is carried out by the mechanic, who is responsible for equipment maintenance and system maintenance.

Three common threads are given: straight thread, tapered thread and trapezoidal thread.

List three commonly used hydraulic control valves: electromagnetic directional valve, overflow valve, pressure reducing valve and sequence valve.

The mating characteristics used in mechanical production are: interference fit, over fit and clearance fit.

The same parts can be interchanged with each other, but the characteristics that can still ensure the performance requirements of the machine or parts are called parts interchangeability. (tolerance fit)

Dimensional tolerance refers to the variation of allowable dimensions, that is, the absolute value of algebraic difference between the maximum limit dimension (or upper deviation) and the minimum limit dimension (or lower deviation).

Interchangeability conditions, that is, to ensure the consistency of technical requirements such as size, geometric shape, mutual position and surface roughness of parts.

The algebraic difference obtained by subtracting the size of the mating shaft from the size of the hole is called clearance when it is positive and interference when it is negative.

Among the coordination codes, the molecular code H is based on hole system and the denominator code H is based on shafting.

When drilling, the rotary motion of the drill bit is the main motion, and the axial motion is the feed motion. (Basic knowledge of metal cutting)

Twist drills are generally made of high-speed steel and hardened to HRC62-68. Consists of a handle, a neck and a working part. There are two kinds of handles: straight handles and tapered handles. (Drilling, reaming and reaming)

The diameter of the drill bit is greater than 13mm, and the handle generally adopts Morse taper handle.

When the accuracy of the hole is high and the surface roughness is low, the cutting time is short and the cutting speed is high.

Thread elements include tooth type, nominal diameter, pitch, thread number, thread tolerance zone, rotation direction and screw length. (Tapping thread and socket thread)

When tapping, the cutting edge of the tap squeezes the material, so the diameter of the bottom hole must be larger than the diameter of the screw hole before tapping.

The axial distance between two adjacent teeth on the pitch diameter is called pitch.

Nominal diameter of thread refers to the basic size of the large diameter of thread, that is, the diameter of external thread crest and internal thread root.

When machining internal threads with the same diameter on steel and cast iron, the bottom hole diameter of steel is slightly larger than that of cast iron.

Drilling machine can generally complete drilling, reaming, reaming, reaming and tapping. (drilling machine and jig)

Hydraulic transmission takes liquid as the working medium, and the mechanical energy of the prime mover is converted into hydraulic energy through the power element. Then, with the help of the executive element, the hydraulic energy of the oil is converted into mechanical energy through pipelines and control elements, and the load is driven to realize linear or rotary motion.

Hydraulic pump is an energy device that converts mechanical energy into hydraulic energy. Commonly used hydraulic pumps are gear pump, vane pump and plunger pump.

The common wear forms of chain transmission mechanism include chain elongation, chain and sprocket wear, link fracture and so on.

Belt transmission uses the friction between belt and pulley to transmit motion and power, which is suitable for transmission with large center distance between two shafts.

According to the types of rolling elements, rolling bearings are divided into roller bearings, ball bearings and needle bearings.

Rolling bearing is a kind of bearing with rolling friction, which generally consists of outer ring, inner ring, rolling body and cage.

Secondary maintenance is a periodic and planned repair work with technicians as the mainstay and operators as the supplement.

Scribing is divided into plane scribing and three-dimensional scribing.

The basic elements of thread are tooth type, large diameter, pitch, number of threads, thread tolerance zone, rotation direction and screw length.

Right or wrong

(√) The gear is fixed on the shaft. When a large amount of interference is needed, the hydraulic sleeve method should be used for assembly.

(√) Choosing appropriate positioning elements can ensure the stability of workpiece positioning and the minimum positioning error.

(x) If the micrometer cannot rotate due to impact, the operator should immediately disassemble it for inspection and adjustment.

(x) When drilling a deep hole with an extended drill bit, you can drill to the bottom without quitting chip removal halfway.

(x) When tapping on tough materials, it is not allowed to add cooling lubricant to avoid reducing thread roughness.

(√) When the material is bent, the neutral layer is generally not in the middle of the material, but biased to the side of the inner material.

(x) In belt drive, the belt that does not slip is a flat belt.

(√) The workpiece should be clamped on the left side of the vice for easy operation.

(√) Hydraulic system generally consists of power part represented by hydraulic pump, executive part represented by hydraulic cylinder, control part represented by various control valves and some auxiliary devices.

(x) When the vise clamps the workpiece, a long tube can be placed to tighten the handle to increase the clamping force.

(x) Parts must cross before machining.

(√) The length of the saw blade is expressed by the center distance of the mounting holes at both ends.

(x) When sawing, the smaller the sawing angle, the better.

(x) The main purpose of adding cutting fluid during drilling is to improve the surface quality of the hole.

Multiple choice question:

1. The reason why the grinding table crawls at a low speed may be (b).

A. Inevitable oil leakage in the system B. Air is mixed in the system.

C, hydraulic impact D, cavitation phenomenon

2. When the aperture is large, the cutting speed of (c) should be taken.

A, arbitrary B, larger C, smaller D, medium speed

4. Do not wear gloves when operating (A).

A, drilling machine B, lathe C, milling machine D, machine tool

5. There are three kinds of documents: ordinary documents, special documents and (c).

A, knife file b, diamond file c, plastic file d, oval file

6. When the strength and hardness of the workpiece are large, the tool life (B).

A, the longer B, the shorter C, the same D, it doesn't matter.

7. A group of devices that transfer energy from the prime mover to (a) are called transmission devices.

A, working machine b, motor c, gasoline engine d and receiver

8. The basic principle of disassembly is that the disassembly sequence is opposite to (a).

A. assembly sequence b, installation sequence c, assembly sequence d and adjustment sequence.

9.(c) Chips will be formed when cutting metal materials with greater plasticity.

A, ribbon b, crushing c, granular d, crushing

10. Hydraulic transmission relies on (b) to transmit motion.

A, oil pressure b, the change of sealing volume

C, piston movement d, oil flow

1 1. What can keep the transmission ratio unchanged is (c).

A, belt drive b, chain drive c, gear drive d and friction wheel drive

12. The algebraic difference between the minimum limit size of the hole and the maximum limit size of the shaft is positive, which is called (b).

A, clearance value b, minimum clearance c, maximum clearance d and maximum allowance

13. When chiseling hard materials such as hard steel or cast iron, the wedge angle is (c).

a、30 ~50 B、50 ~60 C、60 ~70 D、70 ~90

14. The function of the power part of hydraulic transmission is to convert mechanical energy into liquid (C) A, heat energy B, electric energy C and pressure potential energy 15. The power part of hydraulic transmission generally refers to (B) A, motor B, hydraulic pump C and accumulator 16. The function of hydraulic transmission work part is to convert hydraulic potential energy into (A) A and mechanical energy B. A, rotary cylinder B, overflow valve C and reversing valve 18. Under normal circumstances, the height of the oil pump and oil should be limited below (c), otherwise it is easy to precipitate air in the oil and cause cavitation. a、 1000mm B、6000mm C、500mm 19。 Usually, the oil temperature in the oil tank of the hydraulic system is within the range of (b). a、40 ~ 50℃ B、55 ~ 65℃ 65 ~ 75℃ 20。 The accumulator of hydraulic system is a device for storing and releasing (A). A, liquid pressure energy b, liquid heat energy c and electric energy 2 1. The flow control valve controls and adjusts the flow of oil through the valve port by changing (c), so that the actuator can generate corresponding movement speed. A, the size of the liquid pressure b, the size of the liquid velocity c, the size of the channel opening.

22. The temperature rise of rolling bearing shall not exceed (a). When the humidity is too high, check the reasons and take correct measures to adjust. a、60 ~ 65℃ b、40 ~ 50℃ c、25 ~ 30℃ 23。 The maximum radial movement of one ring and the other ring of a fixed rolling bearing is called (B) A, radial displacement b, radial clearance c and axial clearance 24. The roller and raceway of the bearing will wear in use, and when the wear reaches a certain level, the rolling bearing will (. A, overheating B, stuck C, rolling instability

Questions and answers:

What are the advantages of belt drive compared with other mechanical drives?

Answer: (1), the belt is elastic, which can reduce the impact and vibration and run smoothly without noise.

(2) It can be used for transmission with large center distance between two transmission shafts.

(3) In case of overload, the belt will slip on the pulley, which has overload protection function and can avoid the damage of other components.

(4) The belt drive has simple structure, easy manufacture, convenient maintenance and low cost.

What are the characteristics of worm drive? Where is it used?

Answer: (1), with large bearing capacity.

(2) Large transmission ratio and compact structure.

(3) The transmission is accurate, smooth and noiseless.

(4) Self-locking: that is, only the worm can drive the worm wheel, but the worm wheel cannot drive the worm drive.

(5) Low transmission efficiency and easy heating.

(6) The worm gear is made of bronze, which reduces friction and improves transmission efficiency, resulting in an increase in material cost.

(7) Worms and worm wheels cannot be engaged at will.

(8) The cost of hob for machining worm gear is high.

Worm drive is suitable for occasions with large transmission ratio, compact structure, stable transmission and self-locking, such as speed reducer, chain pulley, lathe feed mechanism and machine tool indexing head.