MindMap Gallery Mechanical transmission
This is a mind map about mechanical transmission. The main content includes: chain transmission and belt transmission. Mechanical transmission is a device that converts power from one form to another. It is widely used in various mechanical equipment to achieve control of speed, torque and direction.
Edited at 2024-10-26 23:38:37Diese Vorlage zeigt die Struktur und Funktion des Fortpflanzungssystems in Form einer Mind Map. Es führt die verschiedenen Komponenten der internen und externen Genitalien ein und sortiert das Wissen eindeutig aus, um Ihnen dabei zu helfen, mit den wichtigsten Wissenspunkten vertraut zu werden.
Dies ist eine Mind Map über die Interpretation und Zusammenfassung des Beziehungsfeldes E-Book, des Hauptinhalts: Überblick über die Essenzinterpretation und Übersicht über das Feld E-Book. "Relationship Field" bezieht sich auf das komplexe zwischenmenschliche Netzwerk, in dem ein Individuum andere durch spezifische Verhaltensweisen und Einstellungen beeinflusst.
Dies ist eine Mind Map über Buchhaltungsbücher und Buchhaltungsunterlagen.
Diese Vorlage zeigt die Struktur und Funktion des Fortpflanzungssystems in Form einer Mind Map. Es führt die verschiedenen Komponenten der internen und externen Genitalien ein und sortiert das Wissen eindeutig aus, um Ihnen dabei zu helfen, mit den wichtigsten Wissenspunkten vertraut zu werden.
Dies ist eine Mind Map über die Interpretation und Zusammenfassung des Beziehungsfeldes E-Book, des Hauptinhalts: Überblick über die Essenzinterpretation und Übersicht über das Feld E-Book. "Relationship Field" bezieht sich auf das komplexe zwischenmenschliche Netzwerk, in dem ein Individuum andere durch spezifische Verhaltensweisen und Einstellungen beeinflusst.
Dies ist eine Mind Map über Buchhaltungsbücher und Buchhaltungsunterlagen.
Mechanical transmission
Belt drive
Working principle and type
Friction belt transmission (uses the friction force generated between the belt and the pulley when the driving wheel rotates to drive the driven wheel to rotate)
flat belt
The working surface is the inner surface
V-belt
The working surface is on both sides (can produce greater friction and is the most widely used)
Poly V-belt
It has the advantages of both flat belt and V-belt, and is mainly used in occasions with high power and compact structure.
round belt
The transmission capacity is small and is often used in instruments and household machinery.
Meshing belt transmission (there are equidistant teeth of a certain shape on the inner circumference of the transmission belt that mesh with the corresponding tooth grooves on the pulley. There is no slippage between the belt and the pulley, so this belt transmission is called synchronous belt transmission)
Belt drive characteristics and applications
advantage
Simple structure
low price
Smooth transmission
Buffering and vibration absorption
Slip during overload to prevent damage to other parts
shortcoming
Transmission ratio is unstable
The overall dimensions of the transmission are larger
Less efficient
Belt life is shorter
Greater stress on the shaft due to belt tension
application
Medium and small power transmission (not exceeding 50kW)
In multi-stage transmission systems, it is often used in high-speed stages
Mostly used in occasions with large center distance
Force analysis and slipping phenomenon of belt drive
Force analysis
The difference in tension between the two sides of the belt is called the effective tension of the belt drive, which is the circumferential force transmitted by the belt. It is the sum of the frictional forces on the contact surfaces of the belt and the pulley.
slipping phenomenon
When the power of the belt drive exceeds this limit, significant relative sliding will occur between the belt and the pulley, a phenomenon called slipping. Slippage will cause serious wear and tear of the belt. Slippage should be avoided during belt transmission.
Factors affecting maximum circular force
Initial pulling force (the greater the initial pulling force, the greater the maximum circular force)
Wrapping angle a (the larger a, the greater the maximum circular force)
Friction coefficient f ((the greater the friction coefficient, the greater the maximum circumferential force)
Elastic sliding and transmission ratio in belt transmission
Belt elastic sliding during rotation
This kind of sliding between the belt and the pulley caused by the elastic deformation of the belt is called the elastic sliding of the belt. This is an inherent characteristic of the normal operation of the belt drive and cannot be avoided.
Belt drive ratio
i=n1/n2=d2/d1/(1-e)
V-belt and pulley
V-belt models and specifications
Ordinary V-belt
composition
wrapping cloth
Tensile body
Top glue
Primer
Marking method
Truncated
base length
Standard number
Narrow V-belt
Wide V-belt
Joint V-belt
Large wedge angle V-belt
Material and structure of V pulley
Material
Cast iron (HT150, HT200) is commonly used as pulley material. The maximum allowable peripheral speed of cast iron pulleys is 25m/s. Cast steel can be used when the speed is higher. In order to reduce the weight of the pulley, the pulley material can also be aluminum alloy or engineering plastic.
structure
rim
Wheel groove wedge angle
32°
34°
36°
38°
wheel hub
web
base diameter
2.5-3 shaft diameters
implement pulley
≤300mm
Web pulley or orifice plate type
>300mm
Oval spoke pulley
Design steps of ordinary V-belt transmission
Selection
Determine the reference diameter of the pulley and calculate the belt speed
Determine the center distance and reference length of the V-belt
Check the wrapping angle of the small pulley
Determine the number of strips
Belt drive tensioning, installation and maintenance
Tension
Tighten the belt by adjusting the center distance
Tension with tension wheel
Installation and maintenance
When installing the belt drive, the two shafts must be parallel and the grooves of the two pulleys must be aligned.
Protective cover should be added
When the V-belts need to be replaced, the same set of V-belts should be replaced at the same time, and old and new ones cannot be used together.
The tape should not be in contact with acid, alkali or oil; the working temperature should not exceed 60°
Timing belt drive
advantage
Stable transmission, accurate transmission ratio, etc.
shortcoming
Both manufacturing and installation require higher precision and higher costs
application
Large equipment such as medium and small power transmissions or compressors that require accurate transmission ratios
chain drive
Characteristics and applications of chain drives
advantage
No elastic sliding and slipping phenomena, ensuring accurate average transmission ratio
High transmission efficiency
The chain does not need to be tensioned very tightly around the pulley like a belt
Compact structure
Can work in high temperature, low speed and oily environments
Low installation accuracy and low cost
The structure is lightweight when the center distance is large
shortcoming
The instantaneous chain speed and instantaneous transmission ratio are not constant, so the smoothness of the transmission is poor, and there is impact and noise during operation.
application
Transmissions in mining machinery, agricultural machinery, petroleum machinery, and motorcycles
Chains and sprockets
roller chain
Tooth chain
Principles for selecting chain pitch
Transmission ratio: i=n1/n2=z2/z1
When designing chain transmission, a small-pitch chain should be selected as much as possible on the premise of meeting the transmission power. Optional small pitch multi-row chain for high speed and heavy load
Arrangement, tensioning and lubrication of chain drives
layout
The two axes should be parallel, the two wheels should be on the same plane, and the inclination angle with the horizontal plane should not exceed 45°.
Tension
When the transmission center distance is adjustable, the tension can be controlled by adjusting the center distance.
When the transmission center distance cannot be adjusted, a tensioner wheel can be installed or 1-2 links can be removed from the chain after it is worn and stretched.
lubricating
Significance: Good lubrication can reduce wear and noise and extend chain life
Method: Select from the relevant design data based on the chain speed and chain pitch.