There are many solutions for attaching a gear to a shaft. Here are a few ideas which should help you in your installation:
| Attachment with a fixing screw | Attachment with a Key and Circlip | ||
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| Attachment with a Cotter pin | Attachment with a Locking assy. | ||
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| Attachment with a Locking ring | Attachment with a Self-lubricating bush | ||
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| PRINCIPALS Assembling the screw is quite simple. It just needs a threaded hole to be punctured into the machine’s hub, and machining the flattened area on the shaft. This will help the forces to concentrate on the edges of the cup headed screws (GM and SM) |
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ADVANTAGES This type of fixing improves adherence and prevents any kind of misalignment during the operation. Also, this kind of mounting limits transmissibility. It is therefore recommended to fix the low module gear wheels this way. (Generally, the threaded hole is standard on all HPC pulleys) |
| PRINCIPAL The key attached with the gear and shaft functions as a spigot, it stops rotation between the two. A groove or keyway works as a key element in a machine, it intensifies the productivity if it’s attached to the bore and shaft. They are cut into the bore for traversing the whole width of the gear hence basically function as manufacturing practicalities. |
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| A parallel key – is a rectangular piece of metal, embedded into shaft and hub. Next, the machining of the groove in the shaft is done by aiding it with a two-bladed cutting tool. So, a keyway of the parallel key is excellent for the transmission of high torque levels. |
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| Disk (or half-moon) keys are used for the transmission of weaker couples. The machining of the keyway into the shaft is very easily accomplished by utilizing a three-bladed cutter. | |
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A keyway does not interrupt the axial movement of the system. Therefore it should be incorporated with another locking system, such as a thread and bolt, or more, simply by using circlips. |
Attachment with circlips
| PRINCIPAL Circlips, stop axial movement between two components.There are two types of circlips – one is used for shaft mounting and another is used inside the bore. UTILISATION For the utilization of these elements, a groove is required to be cut into either the bore or the shaft, then they fit axially, from one end of the shaft or bore with the aid of a specialized tool. Attention, a minimum (or maximum) clearance diameter is needed for the installation. |
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| The use of these components is often associated with a KEYWAY in the assembly of pulleys or spur gears. | ||||
Assembly with cotter pins
| PRINCIPAL The cotter pin has the effect of immobilizing one component concerning another, hence they assure accurate relative positioning of the two pieces, or of transmitting a movement. Besides, it can also act as a securing element by shearing away in the event of a violent surcharge. UTILISATION Essentially, the pin is subjected to shearing, and should therefore be used in cases where there is relatively little torque involved – The piercing of the pinholes is generally done after assembling the components in order to assure perfect alignment. However, it’s not recommended to use where frequent removal is necessary.
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For the use of a cylindrical cotter pin, the machine is required to pierce a hole through the shaft and gear. A rough hole can do the job as the pins can adjust by deforming in their seating. This property enables them to resist vibration while providing more stability. Therefore, this type of assembly is excellent for small toothed wheels or pulleys, or gears with low modules. |
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Installation with a Locking assembly.
| PRINCIPAL By tightening the screws, the user can deform a conical ring, and inflict a strong force between the shaft and bore. Hence, the obtained liaison would be complete, rigid (i.e. backlash-free), and easily removable. Methods of fixing to a shaft -> Methods of fixing to a shaft ALTF11 |
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| ADVANTAGE By avoiding the manufacturing accidents which can be caused whilst cutting keyways etc, the system increases the sectional strength of the shaft while decreasing the concentration of stress points and the phenomenon of metal fatigue cracking. For equal diameters, the transmissible couple with this method is much higher. Thus, the work done on the shaft and bore gets limited to ensure H8/h8 tolerance and a surface finish of at least Ra=1,6mm for self-centering assemblies (RT25 and RTL450). A guide should be envisaged for the other assemblies. These locking assemblies are recommended for all types of toothed wheels, and especially for pulleys, sprockets, and gears with large pitches or important modules. |
Attachment by locking ring
| Attachment by locking ring is a fast and efficient method of attaching all types of toothed wheels. There exists two solutions for it – the first is, locking with half a locking ring (type CT), another is, locking with the aid of a full collar (CC). | |||||
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THE USE OF A HALF-ROUND RING (CT)
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USING A LOCKING RING (CC)
In both cases, the result has a completely rigid joint, which is perfect for the transmission of high levels of torque. |
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Assembly by self lubricating bush.
| PRINCIPAL This very simple system provides reliable, simple, and efficient rotational guidance. It limits friction between the shaft and bore with the employment of two self-lubricating bushes (type QAF or QAG), and at the same time, prevents the axial movement from rotating objects. The locking elements are the most practical locking rings (CT or CJ). They have no requirement for special machining and can be positioned at any point on a shaft, just require adjustments to the position of the pivot point. |
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| The use of self-lubricating Ollieare QAG or QFM bushes imposes a maximum tolerance of f7 on the shaft and H8 on the bore (see ISO 2795 and 2796). | |||||
