What is mechanical transmission? Analysis of the advantages and disadvantages of several common mechanical transmission methods

   　Mechanical transmissionDesign is an important part of non-standard mechanical design. Choosing the right mechanical transmission mode is one of the important tasks to be determined in the scheme design, which directly determines the advantages and disadvantages of the scheme, the cost and the performance of the equipment, including productivity, accuracy and reliability, and can reflect the engineer's design ability level and rich experience.

Our fundamental application in mechanical design is the practice of mechanical theory. The obvious representative of mechanical theory and practice here is the design of mechanical transmission mechanism.

1. Mechanical transmission gear transmission is mainly divided into plane gear transmission and space gear transmission.

Advantages: It is suitable for a wide range of circumferential speed and power; the transmission ratio is accurate, stable and high efficiency. High reliability and long service life. Transmission between parallel axes, intersecting axes at any angle, and staggered axes at any angle can be achieved.

The disadvantage is the need for higher manufacturing and installation accuracy and higher costs. Not suitable for long-distance transmission between two shafts.

2. Mechanical transmission Worm gear transmission is used for motion and power between two axes that are perpendicular and non-intersecting in space.

Advantages: large transmission ratio, compact structure and size.

Disadvantages: large axial force, easy to heat, low efficiency, only one-way transmission.

3. Mechanical transmission chain transmission chain transmission, compared with gear transmission, its main features are: lower requirements for manufacturing and installation accuracy; when the center distance is large, its transmission structure is simple; but the instantaneous chain speed and instantaneous transmission ratio are not constant, The transmission stability is poor.

4. Belt drive, including driving wheel, driven wheel and annular belt.

Used when two axes rotate in parallel and in the same direction, it is called the concept of opening motion, center distance and wrap angle. According to the cross-sectional shape, belts can be divided into three categories: flat belts, V-belts and special belts.

When applying mechanical transmission, pay attention to: calculation of transmission ratio; stress analysis and calculation of belt; allowable power of single V-band.

Advantages: It is suitable for transmission with large center distance between two shafts; the belt has good flexibility, can reduce impact and absorb vibration; it must slip when overloaded to prevent damage to other parts; the structure is simple and the cost is low.

Disadvantages: The external size of the transmission is large; a tensioning device is required; a fixed transmission ratio cannot be guaranteed due to slippage; the belt life is short; the transmission efficiency is low.

Let's talk about two types of gear trains: fixed-axle gear trains and epicyclic gear trains. The transmission ratio of the epicyclic gear train cannot be calculated directly by solving the transmission ratio of the fixed-axis gear train, but by using the principle of relative motion and the relative speed method (or inverse method) to convert the epicyclic gear train into an imaginary fixed-axis gear train. It is suitable for transmission between two shafts far apart; it can be used as a transmission to realize variable speed transmission; a larger transmission ratio can be obtained; the synthesis and decomposition of movement can be realized.

The above is a small series to introduce to you about the common typesMechanical transmissionThe advantages and disadvantages of the method are analyzed, hoping to help everyone.

Cut three samples with a length of 250 mm from one PJ V-ribbed belt, and mark a marking line with a spacing of 100mm at the middle position of the PJ V-ribbed belt. When more than three samples cannot be taken from one PJ V-ribbed belt, samples can be cut from the same batch of PJ V-ribbed belt, but must be indicated in the report. 7.4.2 High temperature resistance test method
Place the sample at 100 ℃ ± 2 ℃ for 96 h ± 1 h and then take it out. After standing at laboratory temperature for more than 2h, bend it along a cylinder with a diameter of 20 mm at a contact angle of at least 90 °.