How to calculate the total efficiency of a series system... The mechanical principle part of the kne

In fact, the total efficiency of the tandem system is the best calculation, which is the product of the efficiency of each level. For example, the efficiency between the motor and the reducer, the efficiency between the reducer and the output shaft is, and the efficiency of the output shaft doing external work, then the efficiency of the system is.

It's simpler if there are values for input and output, total efficiency = output input.

The efficiency of each is obedient.

The more series, the lower the efficiency, the greater the investment, and the higher the maintenance and repair cost. Because no system is 100% efficient. This is also a mechanical principle.

Gearing efficiency experiments.

First, the purpose of the experiment.

1. Understand the structural characteristics and working principle of the closed (closed) gear testing machine.

3. Measure the transmission efficiency of the gears on the closed gear testing machine.

2. Experimental conditions.

1. CLS-II gear transmission testing machine.

Third, the content of the test.

The closed gear testing machine has 2 identical gearboxes (suspension gearbox 7 and fixed shaft gearbox 4), and there are 2 identical gears in each gearbox that mesh and drive with each other, and two experimental gearboxes are connected by two shafts to form a closed gear transmission system. When this transmission system is driven by motor 1 to run, the power transmitted by the motor to the system is enclosed in the gear transmission system, and the two pairs of gears are self-driving with each other;Due to the friction and other energy losses, after the system is running, in order to make the system run continuously, the motor continues to provide the energy lost in the energy consumption of the system.

1.Suspension electric motor.

Sensors...Gearbox.

Gear pairs...Axis.

8.Load the weights.

To calculate the gearing efficiency, the output power of the motor and the power transmitted within the closed system are measured.

The motor power is p1: p1 n·t1

kw)n: motor speed, t1: motor output torque;

The power p2 transferred within a closed system: p2=t2n

9550=wln

kw)w: gravity of the added weight (n);l: length of the loading lever, l=

m；n--The speed of the motor and the closed system.

Therefore, the transmission efficiency of a single-stage gear is:

Fourth, the experimental procedure.

1 Before turning on the power supply, you should gently turn the motor speed control knob counterclockwise to the end to avoid the motor starting suddenly when the machine is turned on.

2 Turn on the power and press the "Reset Button" to clear it; At this time, the speed display is "0", and the motor torque display is "·", indicating that the system is in the state of "automatic zeroing"; At the end of the zero, the torque is displayed as "0".

3 After ensuring that all the loading weights are removed, adjust the speed control knob of the motor so that the motor speed is 600

r min.

4. Add the first weight (10N) to the weight basket, and after the display is stable (after the general speed regulation or loading, the speed and torque display value can jump 2-3 times to reach the stable value, and do not need to be written in the test report), press the "hold button" to keep the display value unchanged at that time, and record the group of values; Then press the "Load Button" once, the first loading indicator lights up, and out of the "Hold" state, indicating that the first point loading is over.

5. Add the second weight to the weight basket and repeat the above operation until 8 weights are added, the 8 loading indicators are fully lit, and the speed and torque indicators display "8888" respectively, indicating the end of the experiment.

6. After recording each set of data, the motor speed should be slowly adjusted to zero, and then the power of the test bench should be turned off.

7. From the recorded data, the transmission efficiency (-t2) curve of the geared closed transmission system is made.

Total Efficiency = Belt Drive (Bearing Bearing Gears, First Shaft) (Bearing 2 Gear 2, Second Shaft) (Bearing Bearing Gears, Third Shaft) Belt conveyor, omitting all "efficiency".

The total efficiency is equal to the efficiency of the belt multiplied by the efficiency of the gear multiplied by the efficiency of the bearing multiplied by the efficiency of the coupling; The efficiency of the gear should be squared, and the bearing should be cubic of the gear.

7 efficiency multiplication, which are belt drive, bearing, gear, bearing, gear, bearing, coupling.

Flip the formulas yourself, all in the engineering mechanics major decades ago!

Because it is a standard spur cylindrical gear, the pressure angle (20 degrees), the tooth top height coefficient (equal to 1), and the top clearance coefficient (equal to the standard value Then the number of teeth of gear 2 is equal to i12 xz1=40 Indexing circle radius: r1=,r2= base circle radius: rb1=r1·cosa=,rb2=r2·cosa= pitch circle and index circle.

The velocity scale, acceleration scale, and length scale in the mechanical principle can be determined by themselves, as long as the size of the diagram is appropriate and easy to calculate.

The transmission ratio error is mainly caused by manufacturing errors, gear clearance and other factors, this error is very small, and the actual design calculation is basically not considered, and the main concern is the efficiency loss of gear transmission, which also contains the components of transmission ratio error.

There are 10 rotating bai pairs, 1 moving pair, and 1 high pair. There are 8 moving parts, the self-degree is equal to the point is the composite hinge, the point A is the local constraint, and the roller and the AD rod are one moving piece. Point A is not a composite hinge.

IHG is a rack, which is a component. The EF rod is a virtual constraint, and removing it does not affect the motion.

Calculate the degree of freedom of the mechanism, calculate the degree of freedom of the mechanism according to the following formula, where n is the number of active members; PL is two gears with low Z=10, one for the standard gear and one for the positive displacement (non-undercut) gear.

There are 10 rotating pairs, 1 moving pair, and 1 high pair. There are 8 moving parts, the point with equal degrees of freedom is the composite hinge, the point A is the local constraint, and the roller and the AD rod are one moving piece. Point A is not a composite hinge.

IHG is a rack, which is a component. The EF rod is a virtual constraint, and removing it does not affect the motion.

Self-study of mechanical principles and do the following things:

If you know what the mechanical principle is about, you can first read the introduction in the book, and then read the table of contents again to know what each chapter is about;

Before the teacher speaks, take a general look at it, so that even if you miss a little bit in the class, it will be fine;

The first two links don't take too long, but they are very helpful in improving the efficiency and overall grasp of the class;

In addition, you can ask the seniors who are better at learning which ones are more difficult;

As far as I know, the gear part is a bit difficult, and the rest is something to memorize;

Do more questions and practice more.

There are many self-study methods, and I suggest using the following steps: 1. First choose a college level of "Mechanical Design" to understand the mechanical principles. 2. Grasp the core of mechanical principles

Understand the problem from the perspective of kinematics and dynamics. 3. Don't drill the tip of the horns, don't just put it down, learn down, and look back later. 4. The content of mechanical principles is not closely related, and each chapter breaks through.

5. Choose another textbook that suits you to improve your learning.

The cloud disk link has been sent to you in a private message, and you can see if you need it.

Learning endlessly, I hope it can help you, if you are satisfied, if you are not satisfied, please continue to ask.