Find the high finger of the mechanical class and point down. Masters of mechanical engineering ask f

Briefly, a motor (generator, motor) works with two magnetic fields acting in relative motion, with the magnetic field of the rotating part as the rotor and the rotor of the fixed part as the stator. Generally speaking, one of them is the working magnetic field. One is to control the magnetic field, which is to control the strength of the magnetic field by the magnitude of the current - excitation.

In addition, some motors use permanent magnets and do not require current as an electric magnetic field, and this kind of motor is called "permanent magnet motor". The magnetic field can be generated by energizing is called "excitation", and the excitation is divided into "self-excitation" and "other excitation", self-excitation is excitation by the electric energy emitted by the generator itself, and other excitation is excitation by the current provided by external electrical energy. The reference books are as follows:

1. "Principles of Motors" [Paperback] Machinery Industry Press; (Basic primer knowledge is available).

2. "Motor Principle and Drag" (2nd Edition) [Paperback] Peng Hongcai Yuan.

Briefly, the motor (generator, motor) works on the basis of the relative action of the two magnetic fields, the rotating part of the magnetic field of the rotor, and the fixed part of the rotor is a stator. Generally in a working magnetic field. One controls the strength of the magnetic field - the magnitude of the excitation current.

Also, some permanent magnet motors with no current power magnetic field, which are known as permanent magnet motors. Energizing generates a magnetic field, known as "excitation", which excites energy "self-excitation" and "excitement", and self-excitation emits the generator itself into energy excitation currents excitation by external excitation and excitation. Refer to the following:

br > Principles of Electric Motors [Paperback] Machinery Industry Press Yen (Introductory Knowledge).

2, the principle of the motor and the basis of dragging" (2) [paperback] Pang Xi um yen yuan.

DNF Mechanic Growth Strategy.

It's very simple, you should take a look at the mechanics before you talk about it.

Why can't today's students ask such questions?

f = p*s

s =r = =

p = pa ~~pa

So you can figure it out for yourself.

A is the angle of rotation from point C to point D, B is the angle of pressure, and S is the current displacement.

The process of doing the questions is all in the picture!

The key to this is that the extension of the driven rod is tangent to the offset circle at all times (i.e., the distance from the cam frame axis to the rod is always equal).

Notice that the blue dotted line leads from the center of the circle, passes past point d, and then intersects the red circle.

If you can't, you can contact the station!

The small circle in green is the offset circle, the blue circle is the base circle, and the red circle is the theoretical outline. The magenta rod is the driven rod when turning to the D point position;

In the mechanism, f (or e) is a virtual constraint, one can be removed; B and C are local degrees of freedom, which can be rigidized and regarded as one with the member, so there are 3 moving parts in the mechanism, 2 high pairs, and 3 low pairs, so f=3x3-2x3-1x2=1

A mainspring is a device in the engine that winds a sheet-like steel bar and uses its elasticity to generate power when it is gradually loosened. Mechanical clocks, watches and toys are equipped with clockwork. The calibre's accuracy is exactly the average of the front and back.

With the improvement of modern metallurgical technology, higher quality metal elements are applied to the production of the main spring of the movement, and by changing the metal elasticity and fatigue resistance of the mainspring, the output torque is stabilized as much as possible with excellent physical properties. The watchmaker either grinds the smooth inner wall of the barrel to reduce the release resistance of the spring, or reduces the pendulum frequency, and relatively lengthens the power to achieve a corresponding stable torque range.

True or False: 1 True, 2 False, 3 Wrong (due to elastic sliding error (increasing the wrapping angle and reducing the bending stress when the belt is wound around the small pulley) True, 6 Wrong (V pulley groove angle is determined according to the model of the belt and the diameter of the pulley, so the groove angle of the large and small pulleys is not necessarily equal, wrong (the minimum manufacturing unit is right (line contact is wrong (synchronous toothed belt is not friction transmission) lifting sensitive, 10 wrong.

You think, using the screw rod to drive means that the machine has intermittent movement, which requires stability and accuracy, so the transmission ratio is required to be correct, and the belt drive, when overloaded, there will be slippage between the belt and the pulley, and the slippage will make the transmission fail, and the fixed transmission ratio cannot be guaranteed due to sliding.

Because the V-belt will become longer with the increase of use after use, if you only replace the invalid one, then the new V-belt will be tighter than the other V-belts, and the V-belt will wear out quickly and the service life will be shorter.

1) The first-level transmission of the machine tool is the motor driving the main wheel of the gearbox! This is not a precision transmission grade! The soft transmission with the belt is not only conducive to the smoothness of the motor loading, but also eliminates the inrush current when the motor is started in hard contact!

The spindle and lead screw behind the gearbox belong to precision transmission! Errors in soft transmission are not tolerated! So it's all geared!

2) Multiple belts are replaced in sets! When a strip breaks or slackens, it needs to be replaced! Because you can't make the new one the same length as the original ones!

The old one is no longer the original standard size due to stretching! So it's too tight to find a new one! And the old one is too loose!

Finally, one by one!