Gear redcuers are categorized according to the orientation of the input and output shafts, right-angle or parallel-shaft reducers. These different arrangements use different typees of gearing. For mixer applications, both right-angle and parallel-shaft reducers have advantages and disadvantages. Right-angle reducers are typically shorter than parallel-shaft reducers, allowing them to fit better between floors and below roofs. Conversely, right-angle drives obstruct part of the top ot the tank, which can make piping connections difficult. Mounting and adjusting foot-mounted motors may be easier with right-angle drives than with parallel-shaft reducers.
Parallel-shaft gear reducers use one or more sets of parallel-shaft gears, such as helical gears, to make the necessary speed reduction. Some parallel-shaft reducers have the motor stacked above the worm gear motor to limit the overall diameter of the mixer drive system. Other parallel-shaft reducers have the motor mounted alongside the gear reducer to limit the overall height of th drive system. Generally, parallel-shaft reducers are easier than right-angle mixer drives to design and build. However, they do involve mounting and operating a verical electric motor, which can cause additional problems with large motors.
In-line reducers are usually a variation on parallel-shaft reducers. A properly designed double-reduction reducer with two sets of gearing having the same center distance can be arranged so that the input and output shafts are not only parallel, but in line with one another. Compared with parallel shaft reducers, in-line reducers usually trade greater height for smaller diameter and centered weight. Other types of gearing, such as plaetary planetary gear box, can make an in-line reducer. Whatever the basic configuration, well-designed gear reducers will provide good service in mixer applications.
Right-angle gear reducers must use at least one right-angle gear set, typically spiral bevel or worm gears. Both spiral-bevel and worm gears have unique advantages with respect to mixer applications. Spiral-bevel gears are some of the quietest and most efficient right-angle gears. Although less efficient than other gears, worm gears can make heat dissipation more difficult.
Gear drives are also known as gear reducers or gearboxes. These are rugged mechanical devices desined to transmit high power at high operating efficiencies and have a long service life. The worm gear motor is an important component of the mixer drive systems, providing speed reduction and increasing allowable torque. Moreover, in some cases it provides support to the mixer shaft.
Helical gears are used in parallel shaft gear reducers. In helical gears, gear teeth are machined along a helical path with respect to the axis of rotation. Helical gears are commonly used with two-, three-, and in some cases even four-, five-, and six-stage speed reductions. In-line helical reducers are a variation of parallel shaft speed reducers configured such that the output and input shafts are in-line.
Spiral bevel gears are used when the input and output shafts of the gear reducers are required to be at right angles. The curve shape of the spiral bevel teeth makes gradual contacts, resulting in less noise during operation. Helical, parallel shaft, and helical bevel gear units have high operating efficiency, approximately 98% for each gear stage reduction.
Worm gears, are the most economical speed reducers, capable of providing a sizable speed reduction with a single gear set. The input and output shaft of these gears are at right angles to each other. However, becasue of the sliding contact between the worm pinion and the gear, the worm gear reducer is less efficient. The efficiency decreases as the speed redcution ratio increases. For example, at a speed reduction ratio of 10:1, the efficiency of the worm gearbox may be approximately 90%. However, at a redution ratio of about 50:1, the efficiency of the worm reducer drops to about 70%. Gearbox manufactures offer gear reducers in helical bevel and helical worm design.
Helical, spiral bevel, and worm gears are external gears with the teeth on the outer periphery of the gears. In planetary gears the teeth profile is on the inside of a circular ring with meshing pinion. Planetary gears consist of an internal gear with a small pinion, known as a sun gear, surrounded by multiple planetary gears. These gears can provide high speed reduction ratios and are relatively compact in size. Gear reducer manufacturers also offer geared-motor, that consists of a factory assembled motor with the gear unit. Figure 12.34 shows a variety of gear reducer with motor configurations.
NMRV worm gear series also available as compact and flexibility. NMRV worm gear series also available as compact integral helical/worm option, has been designed with a view to modularity: low number of basic models can be applied to a wide range of power ratings guaranteeing top performance and reduction ratios from 5 to 1000.
One advantage of a gear reduction starter motor over a direct drive motor is reduced mass (weight) of the gear reduction motor.
Another advantage of using a Gear reduction motors is that an increased engine cranking speed over TDC of each engine compression stroke can be obtained, even though the average cranking speed remains about the same as a comparable direct drive motor. This increase in speed over TDC is said to improve the cold start performance of a diedsel engine.
Gear reduction starter motors are also more efficient than direct drive motors. This means that less of the electrical energy that is being converted to mechanical energy is lost as heat. One starter motor manufacturer indicates up to a 40 percent decrease in planetary gear Motor current with the gear reduction motor compared to a comparable direct drive motor. This means less current is also flowing through the cranking circuit, so the available voltage at the starter motor terminals is increased compared to direct drive starters.
Most gear reduction starter motors are soft start motors. The soft start design cuases the armature to rotate slowly as the drive with attached pinion gear is sliding toward the ring gear. This slow rotation of the pinion gear provides a greater likelihood that the pinion gear is fully engaged with the ring gear before fully cranking power is applied, which reduces ring and pinion gear milling. Howerver, the soft-start design also causes most gear reduction starter motors to draw much more current through the motor’s solenoid terminal compared to most direct drive starter motors.
There are four basic types of gear reducers on the market today:helical gears,parellel shaft helical gears,helical bevel gears,and helical worm gears. The latter three types of gear reducers are often used in the theatre industry. Both parallel shaft and helical bevel Gear reduction motors are very efficient in transmittting power from the motor to the output shaft. The helical worm gear reducer is inefficient in its transmission of power from the motor to the output shaft. The helical worm design is the mostly widely used gear reducer type, offering long service life overload and shock tolerance.
Efficient gear reducers are used on most of today’s packaged winch systems. They are also used on most fire curtain motor systems as they are easy to back drive, which is the reverse of the normal operation. The output shaft is used to turn the input shaft. Many fire curtain release systems release the brake on the motor, using the weight of the fire curtain to turn the output shaft of the gear reducer, which turns the motor. A hydraulic dampener attached to the motor controls the descent speed of the fire curtain.
An inefficient gear reducer design does, however, have advantages in the threatre world. A helical worm gear reducer with a gear ratio greater than 60:1 statistically cannot be back-driven. This means that a load on the output shaft will remain staionary even if the motor brake is released. Most line shaft, drum, and counterweight assist winches use this type of planetary gear reducer because of this feature. Helical worm gear reducers are a simple design that is very cost-effective to produce. This design lends itself to the lower output RPM and higher gear ratios used in the theatre industry.
Gear reducers are filled with oil and are vented because the oil will expand as the reducer is used. The oil helps to keep the reducer cool. The reducer will have breather vent and a drain plug. While it may look like as if they can be mounted or oriented in any position, it is very important to be certain that the vent is at the top and drain at the bottom when the reducer is mounted in its final position. The amount of oil with which the reducer is filled varies with the orientation that is used. The orientation is also important regarding the bearings that are installed into the reducer. The manufacturer will install different bearing depending on whether the bearing is below or above the oil level in the reducer. Thus it is important to order a gear reducer for the specific orientation for which it will be used.
Gear reducers also have their own service factor, which is defined by the American Gear Manufactures Association (AGMA). AGMA adjusts a reducer’s ratings relative to the individual load charateristics of the reducer. AGMA’s ratings are based upon time duration. For winches used for between three and ten hous per day the service factor is 1.25. For winches used for more than ten hours per day the service factor is 1.5.
Numerous industrial machines need energy at slow speeds and higher torque. Conveyors and concrete mixers are typcial examples of machinery with such specifications. At speeds of 780 rpm and much less, the following drives might be prudently utilized: chain drive, belt drive, separate speed reducer coupled towards the motor, or gear motor.
The gear reducer motor is really a speed-reducing motor that provides a direct energy drive from a single unit. The gear motor offers an very compact, effective, packaged energy drive. A gear motor generally consists of a standdard AC or DC motor along with a sealed gear train properly engineered for the load. This assembly is mounted on a single base as a 1 package, enclosed pwoer drive. The benefit of this unit is its intense compactness. A gear motor really is smaller sized than a low-speed regular motor from the exact same horsepower.
The motor-shaft pinion of the worm gear motor drives the gear or series of gears in an oil bath that is linked with the output shaft. This type of arrangement is usually the most economical and convenient way to obtain low speeds of approximately 1 rpm to 780 rpm.
One-unit gear motors are available with the following options:(1)shafts parallet to each other or at right angls, (2) polyphase, single-phase, or DC voltages, and (3) horsepower ratings ranging from approximately 1/6 hp to 200 hp.
Gear motor are accessible in numerous from the regular motor kinds like squirrel cage or wound rotor induction motors, operating at either continuous or adjustable speeds. The manage gear for the motor is chosen exactly the same as for any other motor from the exact same kind.
When choosing a gear motor, an essential consideration will be the degree of gear service and gear life primarily based around the load circumstances to which the motor will probably be subjected. Gear motors are divided into 3 classes. Every class utilizes various gear sizes to deal with particular load circumstances. Every class give concerning the exact same life for the gears. The American Gear Manufactures’s Assocation has defined 3 operationg conditons generally discovered in industrial service and has established 3 regular gear classifications to meet these circumstances.
Class I: For steady loads within the motor rating of 8 hours per day duration, or for intermittent operation under moderate shock conditions.
Class II: For 24-hour operation at steady loads within the motor rating, or 8-hour operation under moderate shock conditions.
Class III: For 24-hour operation under moderate shock conditions, or 8-hour operation under heavy shock conditions.
For conditions that are more severe than those covered by Class III gears, a fluid drive unit may be incorporated in the assembly to cushion the shock to an acceptable value.
To achieve multiple speeds, separate units are available with a transmission comparable to that of an automobile. These units must be assembled with the motor and the driven machine. Because the amount of power lost in gearing is very small, the multiple drive has essentially constant horsepower. In other words, as the output speed is decreased, the torque is increased. Generally, this means that larger shaft sizes are needed for the output side.
A worm gear assembly resembles a single threaded screw that turns a modified spur gear with slightly angled and curved teeth. Worm Gear reduction motors may be fitted with either a right-, left-hand, or hollow output (drive) shaft. This correct angle gearing kind is utilized when a sizable speed reduction or perhaps a big torque improve is needed inside a restricted quantity of space. Figure 1 shows a single thread (or single begin) worm along with a forty tooth worm gear resulting inside a 40:1 ratio. The ratio is equal towards the quantity of gear teeth divided by the amount of starts/threads around the worm. A comparable spur gear set having a ratio of 40:1 would need a minimum of two stages of gearing. Worm gears can attain ratios of much more than 300:1.
Worm gears have an inherent design advantage over other gear sets; the worm can easily turn the dc worm gear motor, but the gear cannot turn the worm. In lifting applications, this feature acts as a secondary brake due to limited back drivability.
Worms can be made with multiple threads/starts as shown in Figure 2. The pitch of the thread remains constant while the lead of the thread increases. In these examples, the ratios relate to 40:1, 20:1, and 13.333:1 respectively.
Worm gear sets can be self-locking: the worm can drive the gear, but due to the inherent friction the gear cannot turn (back-drive) the worm. Typically only in ratios above 30:1. This self-locking action is reduced with wear, and should never be used as the primary braking mechanism of the application.
27RPM DC24V 2.45NM 25kg.cm Turbo Worm Gear Motor GW31ZY DIY Robot
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3.Use for labeling machines, remote control curtains, automatic voltage electricity, grills, ovens, washing machines, garbage disposal machines, household appliances, slot machines, the banknote recognition, automatic actuator, coffee machine, towel disposal, lighting, etc.
4.Low speed structure,high power,large output torque,stable performance,small installation space and self lock,etc.
5.This type is low speed Worm Gear DC Motor,self locking.
6.Widely used in various of occasions that require special install size.
The worm gear is usually bronze and the worm is steel, or hardened steel. The bronze component is designed to wear out before the worm because it is easier to replace.
The hoist motor can transmit motion through the gear reducer, but the load cannot transmit motion back through the gear reducer.
Regulates the lowering speed of the load
The load will not be allowed to free fall
OSHA [1910.179] recognizes this as an approved means of controlled braking
In an industry where ‘load brakes’ and ‘regenerative braking’ are widely accepted, Electrolift offers the better option by using a worm drive gearbox as the secondary braking function.
The main advantages of Electrolift’s non-load brake worm drive gear reducer:
Constant load on the load block. Load brake hoists are prohibited from doing this because it does not allow the load brake to release causing overheating and premature failure.
Long lifts – Long lifts cause load brakes to overheat and prematurely fail
Faster lifting speeds – Load brakes accumulate excessive heat as lifting speeds increase.
Inherently safe – Worm drives do not need controls or high maintenance mechanisms to ensure safe lifts.
Low Maintenance – Less moving parts than gearboxes that require complex load brake mechanisms