Car - technical device, which performs the transformation of energy, materials and information in order to facilitate the physical and mental labor of a person, improve its quality and productivity.
There are the following types of machines:
1. Energy machines - converting energy of one type into energy of another type. These machines come in two varieties:
Engines(Fig. 1.2), which convert any kind of energy into mechanical energy (for example, electric motors convert electrical energy, motors internal combustion convert the expansion energy of gases during combustion in the cylinder).
2. Working machines - machines that use mechanical energy to perform work on the movement and transformation of materials. These machines also have two varieties:
Transport vehicles(Fig. 1.4), which use mechanical energy to change the position of the object (its coordinates).
3. Information machines - machines designed to process and convert information. They are divided into:
Math machines(Fig. 1.6), transforming the input information into mathematical model object under study.
4. Cybernetic machines (Fig. 1.8) - machines that control workers or energy machines, which are able to change the program of their actions depending on the state of the environment (i.e. machines with elements of artificial intelligence).
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The concept of the machine unit.
Machine unit called technical system, consisting of one or more machines connected in series or in parallel and designed to perform any required functions. Usually, the machine unit includes: an engine, a transmission mechanism and a working or power machine. At present, a control and management or cybernetic machine is often included in the composition of the machine unit. The transmission mechanism in the machine unit is necessary to match the mechanical characteristics of the engine with the mechanical characteristics of a working or power machine.
Scheme of the machine unit.
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Mechanism and its elements.
Several definitions of mechanism are used in the textbook literature:
First: mechanism called a system of rigid bodies designed to transfer and convert the given movement of one or more bodies into the required movements of other rigid bodies.
Second: Mechanism- a kinematic chain, which includes a fixed link (rack) and the number of degrees of freedom of which is equal to the number of generalized coordinates characterizing the position of the chain relative to the rack.
Third: mechanism called a device for the transmission and transformation of movements and energies of any kind.
Fourth: Mechanism- a system of solid bodies, movably connected by contact and moving in a certain, required way relative to one of them, taken as stationary.
These definitions use previously undefined concepts:
Link- a rigid body or a system of rigidly connected bodies that are part of the mechanism. Kinematic chain- a system of links that form kinematic pairs with each other. Kinematic couple- a movable connection of two links, allowing their certain relative movement. Rack- a link, which, when studying the mechanism, is taken as a fixed one. Number of degrees freedom or mobility of the mechanism- the number of independent generalized coordinates that uniquely determines the position of all its links on a plane or in space.
From theoretical mechanics: Systems of material bodies (points), the positions and movements of which are subject to certain geometric or kinematic restrictions, set in advance and independent of the initial conditions and given forces, is called not free. These restrictions placed on a system and making it non-free are called connections. The positions of the points of the system allowed by the constraints imposed on it are called possible. Quantities independent of each other q 1 ,q 2 , ... q n , completely and uniquely determining the possible positions of the system at an arbitrary moment of time are called generalized coordinates of the system.
The disadvantages of these definitions are: the first does not reflect the ability of the mechanism to transform not only movement, but also forces; the second does not contain an indication of the function performed by the mechanism. Both definitions are in conflict with the definition of a technical system. Given the above, we give the following formulation of the concept of mechanism:
mechanism called a system consisting of links and kinematic pairs forming closed or open circuits, which is designed to transfer and convert the displacements of the input links and the forces applied to them into the required displacements and forces on the output links.
Here: input links- links to which the specified movement and the corresponding force factors (forces or moments) are reported; output links- those on which they receive the required movement and forces.
Starting link- a link, the coordinate of which is taken as a generalized one. Initial kinematic pair- a pair, the relative position of the links in which is taken as a generalized coordinate.
Engine- an energy machine that converts any energy into mechanical work. The main type of power plant in transport is a heat engine - a complex technical system that converts heat into mechanical work.
On domestic cars installed piston engines internal combustion. These engines are classified according to the following main features:
1. According to the method of ignition combustible mixture: compression ignition engines (diesels) and spark (forced) ignition engines (gasoline and gas).
2. According to the method of mixture formation: engines with external mixture formation (gasoline and gas) and with internal mixing(diesels).
3. By type of power control: motors with quantitative and motors with qualitative power control. With quantitative control, the power is changed by the throttle valve due to the amount of air-fuel mixture entering the cylinder, and with qualitative control, by varying the amount of injected fuel with a constant amount of air (by varying the composition of the mixture).
4. According to the method of implementation of the working process: four-stroke and two-stroke engines.
5. By type of fuel used: liquid fuel engines running on gasoline and diesel fuel, and gaseous fuel engines operating on compressed or liquefied gas.
6. According to the number of cylinders: single-cylinder and multi-cylinder engines (two-, four-, six-cylinder, etc.).
7. According to the location of the cylinders: single-row, or linear, engines (the cylinders are arranged in one row) and double-row, or the so-called V-shaped (two rows of cylinders are located at an angle to each other).
Spark ignition engines are characterized by quantitative power control and external carburetion. They can use gasoline and gas. Gasoline engines divided into two modifications - fuel injected engines through the nozzle intake system(usually on inlet valve or into a cylinder) and carburetor (air-fuel mixture entering the cylinders is prepared by the carburetor).
Carburetor engines are being actively superseded by fuel-injected engines. The fuel supply in these engines is carried out according to the signal of the control unit, formed according to the information of the sensor complex (air consumption, rotational speed crankshaft, position throttle valve etc.).
Compression ignition (diesel) engines are characterized by power regulation by changing the composition of the mixture and internal mixture formation.
Test tasks by TMM
assembly based on the materials of the Federal Accreditation Agency
(att. nica. en, i- exam. en), NGPU, KamGPI and department. "Mechanization…",
Assoc. Glukhov B.V.
Thematic structure
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Sections (didactic units) |
Number of questions |
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Schemes, drawing. |
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1. Basic provisions |
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2. Structure |
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3. Kinematics of lever mechanisms |
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4. Dynamics |
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5. Gear kinematics |
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6. Involute gearing |
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7. Cam mechanisms |
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8. Vibration protection |
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Total |
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1.Basic provisions
1. The totality of the means of human activity created to carry out the processes of production and service the non-productive needs of society is ...
1) device 2) mechanism
3) technique 4) knot
2. A machine is a device designed to…
1) performing useful work 2) transforming movements
3) transfer of movements 4) transfer and transformation of movement
3. A device that performs mechanical movements to convert energy, materials and information is ...
1) kinematic pair 2) mechanism
3) machine 4) node
4. Machines are divided into classes according to the functions they perform ...
1) energy, workers, information
2) energy, workers, information, cybernetic
3) working, analytical, informational, cybernetic
4) energy, working, analytical
5. Energy machine is...
1) a machine designed to convert any kind of energy into mechanical energy (and vice versa)
2) a machine designed to convert materials
3) a machine that changes the shape, properties and states of a material or processed object
4) a machine designed to convert information
6. The electric current generator is a machine ...
1) transport 2) technological
3) energy 4) information
7. The working machine is…
1) car - engine
2) a machine that converts information
3) a machine that converts materials
4) cybernetic machine
8. transport vehicle- This…
1) car - engine
2) working machine, changing the shape, properties and state of the material or processed object
3) a technological machine that transforms the shape of an object
4) a machine that changes the position of a moving object
9. Transport vehicles are…
1) automatic machines 2) electric motors
3) automatic lines 4) working machines
10. The mechanism is called ...
1) energy conversion device
2) a device for transferring useful work
3) conversion device mechanical movement
4) a system of moving links connected by kinematic pairs
11. The mechanism is designed to ...
1) doing useful work
2) transmission and transformation of mechanical movements
3) information transfer
4) energy transfer and conversion
12. A device for transmitting and converting rotational motion between two shafts is ...
1) machine 2) mechanism
3) fixture 4) assembly unit
13. A system of bodies designed to transform mechanical movement is called ...
1) mechanism 2) machine
3) technique 4) assembly unit
14. A mechanism, all moving links of which describe trajectories in one plane or in parallel planes, is ... a mechanism.
1) spatial 2) flat
3) linear 4) symmetrical
15. A kinematic pair is called ...
1) fixed connection of two contacting links
2) movable connection of more than two links
3) movable connection of two contacting links
4) two links not connected by kinematic pairs
16. The connection of two contacting links of the mechanism, allowing their relative movement, is called ...
1) kinematic connection 2) structural group
3) kinematic pair 4) kinematic chain
17. A kinematic pair is called superior if...
3) the links are in contact along the plane
4) the links are in contact along the line
18. A kinematic pair is called inferior if...
1) the links are in contact on the surface
2) the links are in contact along a line or at a point
3) the links are in contact along the line
4) the links are in contact in any way
19. Mechanisms with higher kinematic pairs are superior to mechanisms with lower kinematic pairs ...
1) Greater motion conversion accuracy
2) transmission of movement over long distances
3) the ability to transfer large forces
4) using fewer links in the chain
20. An example of a single-moving kinematic pair is a pair ...
1) a cylinder on a plane 2) a ball on a plane
3) screw 4) spherical
21. An example of a two-moving kinematic pair is a pair ...
1) cylinder on a plane 2) cylindrical
22. An example of a three-moving kinematic pair is a pair ...
1) ball on a plane 2) cylindrical
3) rotational 4) spherical
23. An example of a four-movable kinematic pair is a pair ...
1) a ball on a plane 2) a cylinder on a plane
3) rotational 4) spherical
24. The number of degrees of freedom of a kinematic pair in the figure is ...
25. The number of degrees of freedom of a kinematic pair in the figure is ...
26. The number of degrees of freedom of a kinematic pair in the figure is ...
27. The number of degrees of freedom of a kinematic pair in the figure is ...
28. Number of degrees of freedom of a kinematic pair E equals…
29. Number of degrees of freedom of a kinematic pair WITH equals…
30. Number of degrees of freedom of a kinematic pair E equals…
31. Number of degrees of freedom of a kinematic pair IN equals…
32. The kinematic pair shown in the figure is called ...
1) screw 2) translational
3) rotational 4) spherical
33. The figure shows symbol according to GOST 2.770 …
34. The figure shows the symbol according to GOST 2.770 …
1) screw kinematic pair
2) translational kinematic pair
3) cylindrical kinematic pair
4) rotational kinematic pair
35. The figure shows the symbol according to GOST 2.770 …
1) screw kinematic pair
2) rotational double kinematic pair
3) cylindrical kinematic pair
4) rotational kinematic pair
36. The figure shows the symbol according to GOST 2.770 …
1) screw kinematic pair
2) spherical kinematic pair
3) spherical kinematic pair with a finger
4) rotational kinematic pair
37. Kinematic chain is ...
1) a system of links that form kinematic pairs with each other
2) a system of links that form kinematic connections with each other
3) a system of links that form kinematic connections with each other
4) a system of links that form among themselves higher kinematic pairs
38. The mechanism is different from the kinematic chain ...
1) the presence of a fixed link (rack)
2) the absence of a fixed link
3) the presence of moving links
4) the presence of expedient movements
39. In a flat kinematic chain ...
1) all points move in the same plane
2) all points move in two planes
3) all points move parallel to one plane
4) all points move parallel to two planes
40. In a closed kinematic chain ...
1) the output link is not connected to the rack
2) all links are movable
3) the input link is not connected to the rack
4) the input and output links are connected with the rack
2.Structure
1. The number of degrees of freedom of a flat mechanism is determined by the formula ...
1) Malysheva 2) Chebysheva
3) Willis 4) Novikov
2. Chebyshev's formula for calculating the number of degrees of freedom of a flat mechanism has the form ...
1) W = 6n + 5p 5 + 4p 4 + 3p 3 + 2p 2 + p 1
2) W \u003d 3n + 2p 1 - p 2
3) W = 6 n – 5 p 1 – 4 p 2 – 3 p 3 – 2 p 4 – p 5
4) W= 3 n – 2 p 1 – p 2
3. If there is a roller in the cam mechanism diagram, its ...
1) replace with a link and two pairs
2) move to the structural profile
3) remove
4) replace with two links
4. The number of degrees of freedom of the mechanism of mechanical scissors is ...
5. The number of degrees of freedom of a flat mechanism, the kinematic diagram of which is shown in the figure, is ...
6. Number of degrees of freedom of a flat mechanism, kinematic scheme
Designed for the production of thermal and electrical energy (gas generators, electric generators, etc.), as well as motor machines that convert energy of any kind (water, wind, thermal, electrical, etc.) into mechanical (electric motors, internal combustion, etc.)..."
Source:
"on the procedure for economic incentives for the mobilization preparation of the economy" (approved by the Ministry of Economic Development of the Russian Federation N GG-181, the Ministry of Finance of the Russian Federation N 13-6-5 / 9564, the Ministry of Taxes of the Russian Federation N BG-18-01 / 3 02.12.2002)
Official terminology. Akademik.ru. 2012 .
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