EN
![[Translate to English:]](/fileadmin/_processed_/a/d/csm_weiteres-rettungsschere_268678893d.jpg)
Planetary Gears for Rescue shears
Rescue Without CompromiseSituations, in which every second counts.
Situations, in which every second counts. With professional helpers. And state-of-the-art equipment: Help after traffic accidents, help after natural disasters, help after explosions. When robust, effective rescue devices are indispensable. LUKAS Hydraulik (Erlangen) is one of the leading suppliers of these tools. The traditional enterprise uses planetary gears from IMS Gear for its mobile spreading devices and shears of the eDRAULIC series. To make them work when it really matters. And every second counts
With its modular system, IMS Gear’s spectrum ranges from quick quality solutions to customer-specific adaptations and sophisticated special gear configurations. The same applies to our solutions for modern agricultural technology.
- High efficiency
- Stable service life
- High flexibility & wide range of applications
“By using the eDRAULIC, you save about 50% of weight compared to the conventional equipment of a complete rescue set.”
Clear Matter: Rescue in an Emergency
For decades, powerful rescue devices have ranked among the indispensable hydraulic tools of fire departments. The pictures are impressive: Cut up cars at the end of traffic jams from which wedged victims of accidents have been saved, cut up wagons after train crashes, spread out steel doors to gain access after gas explosions.
Conventional solutions, however, have a few drawbacks and limitations.
First of all, conventional hydraulic units need to be set up as drives and put into operation, while hydraulic hoses have to be connected before help can set in. This costs time. The equipment is heavy and takes up a lot of space in the vehicle, and the range of hydraulic hoses is limited by their reach and accessibility. Consequently, a vehicle that has slid down the slope can sometimes not be reached.
Clear Stipulation: No Compromise on the Performance of the Device
These limitations led LUKAS Hydraulik to develop a mobile solution. Dietmar Lindner, design engineer with LUKAS, sums up the basic requirements of the specifications: “No compromise in terms of power, portable, to be operated by one person”. The strategy to reach the goal: Driving the hydraulic pump by a strong electric motor powered by a high-performance battery. “Quite soon, it became evident that the hydraulic pump was overstrained by the very high rotational speed of the electric motor, that doesn’t work”, Lindner recalls. The theoretical possibility to install a significantly higher-torque motor providing the required torque at a bearable rotational speed cannot be put into practice: “The dimensions and weight of such a motor would have blown the whole concept”, Lindner explains.
Clear Technological Requirement: a Gear Between Motor and Pump
Due to the technological requirements it was necessary to install a gear
between electric motor and hydraulic pump. “It soon became apparent that IMS Gear was the desired partner as they really committed themselves, although naturally we just enquired non-automotive quantities”, Lindner explains.
This commitment reflects both the tremendous experience of IMS Gear and the technological ambition to enable innovation: “It quickly became clear that the task to transmit a great force in a very small installation space could only be realized by a planetary gear”, explains Andreas Sigwart, Sales Engineer at IMS Gear. “With our modular system we have the platform to be able to quickly respond to enquiries, provide a technology assessment and subsequently work on a solution.”
Clear Challenge: the Extreme Rotational Speed
The project proved to be extremely challenging. “The modular system from IMS Gear recommends input speeds of 3,000 revolutions. In this case, the electric motor provides 24,000 revolutions at a torque of 0.4 Nm” reports Sales Engineer Andreas Sigwart.” As the installation space is strictly limited, only a 1-stage PLG could be considered. Plastic planetary wheels that due to their lower weight would be advisable had to be ruled out, and the same was true for the gear drive of the product line with a diameter of 42 mm that was first taken into consideration.
“After the first test runs it was clear that we could meet the requirements but had to dig very deep into the module kit”, Sigwart remembers. The 52 mm gear drive proved to be a sufficiently stable basis. As the output speed with about 5,000 revolutions per minute is still ambitious, metal spur gears are used to prevent excessive axial forces resulting from helical gearing. A larger bore of the planetary wheels can provide for a better bearing. The optimized bearing plays a major role anyway: “With a slide bearing, the enormous rotational speed would generate too much heat, thus burn the grease and wear very fast in case of dry running”, Sigwart explains. For this reason, our current series solution features a needle bearing complemented by a special lubricant.
Clear Benefits: the Efficiency of the Modular System
As the individual components are taken from the modular system of IMS Gear and samples are available at low cost and without great loss of time, the test effort is significantly decreased. “With quantities of a few thousand gear drives per year a special development would not have been feasible”, Lindner praises the fruitful cooperation. Especially since IMS Gear is extremely flexible at the output side and the optimum connection to the hydraulic pump could quickly be realized. The hydraulic gear ratio of the pump coming after the planetary gear is 10,000:1 which explains the force of the shears, spreaders and cylinders.In this way, a compact rescue device was created that offers high handling benefits with identical power. “By using the eDRAULIC, you save about 50% of weight compared to the conventional equipment of a complete rescue set including shears, spreader and rescue cylinder”, Lindner explains. If further advances of the batteries, the electric motor or the hydraulics
require modified gear reductions of the planetary gear, all can be implemented from the modular system. “The variability of the IMS Gear module kit and the access to proven components allow quick and cost-efficient derivation”, Sigwart emphasizes the special added value for customers in this strategic option. He adds that with respect to ever shorter innovation cycles quick and above all reliable availability are major preconditions for success not only in technological but also to economic terms. As a first modification, a slimmer motor pinion could save weight. In this case exactly 77 grams. “Weight optimization is a continuous process with individual components adding up to the savings”, Lindner states.
Conclusion
In this project, the modularity and flexibility of the module kit that has been proven for many years pays off particularly well. An efficient and powerful solution, made for emergencies all over the world.
Your are looking for a custom-fit solution for your application? Then let’s talk about it: As an experienced development partner, we at IMS Gear are always excited to develop new solutions for the world of tomorrow.
Get in touch with Helmut Brugger
What Is a Planetary Gear?
A planetary gear (also: epicyclic gear) is a technical design that serves as a “link” for power transmission between a drive source (the motor) and an application to be moved (e.g. the movement of a wheel). For many decades, we from IMS Gear have been renowned experts for the design and manufacturing of planetary gears for a great variety of industrial applications.
Where Are Planetary Gears Used?
The advantage of planetary gears is their ability to combine high power density with little installation space. A further important factor is the low noise emission that can be realized by the specific design. This makes planetary gears an ideal solution for a great variety of applications, e.g.
- logistics (industrial trucks, driverless transport vehicles, ...)
- building technology (e.g. automated access systems, barriers and doors), household devices (e.g. robot lawn mowers, appliances, ...)
- agricultural technology / farming (e.g. feeding and milking robots, seed drills, ...)
- and many more.
How Does a Planetary Gear Work?
Basically, planetary gears work as the name implies: the sunwheel is in the center and driven by the motor. It confers its motion to three rotary planetary wheels which form a stage. They are arranged on the bearing bolts of a planetary carrier. The last planetary carrier is rigidly connected to the drive shaft and so provides power transmission at the output. On the outside, the planetary gear wheels rotate in a gearbox with internal gearing, the so-called ring gear.
Input and output are arranged coaxially with planetary gears, the shafts rotate in the same direction. PLGs are suitable for clockwise and counter-clockwise rotation, alternating, continuous and intermittent operation and are characterized by a high level of efficiency. The compact design offers high power density compared to other gear designs and high torque transmission for extremely small installation space.
If the number of teeth of the sun wheel and planetary wheels is changed, different gear reductions are possible within one stage. We from IMS Gear combine the reductions of our planetary gears in up to four stages. In this way, an enormous variety of different gear requirements can be realized.
Why Is the Output Torque of a Planetary Gear so Important?
Output torque is the most important parameter when choosing a planetary gear. The gear reduction reduces the relatively high rotational speed of the motor (rpm), delivering a lower rotational speed at the output end. This increases the output torque in inverse ratio. To link the planetary gear to the respective application a specific connecting flange is required.
As different manufacturers apply different measuring methods, great care must be taken when seeking to make a comparison. We will be pleased to calculate the maximum axial and radial load for your specific application under consideration of all parameters. Higher loads can be achieved through design measures. We will be happy to develop tailor-made implementation concepts for our customers.
Which Motors Can Planetary Gears Be Adapted to?
The connection between driving shaft (the motor) and the planetary gear is highly individual as there is a great number of different motors (and manufacturers) with particular specifications. This is where manufacturers of planetary gears show their degree of flexibility. Basically, all IMS Gear planetary gears can be adapted to fit all motors available on the market; individual solutions are possible at the input and output sides.
How Relevant Are “Operational Dynamics” and “Gear Backlash” for Planetary Gears?
High levels of operational dynamics are achieved through low inertia torques, smooth running and low levels of mechanical wear. When it comes to designing and manufacturing planetary gears, IMS Gear uses plastic instead of metal for the planetary wheels where appropriate and technically feasible. This delivers low inertia torques. If necessary, we achieve smooth running through high-quality needle bearings or low friction coefficients between metal and plastics, low levels of mechanical wear through a special gearing design and the use of plastics wheels. In a nutshell: The material mix typical of IMS Gear ensures excellent operational dynamics.
In this context, the gear backlash of the planetary gear has to be considered. It depends on many factors: Type of load, number of stages, bearing, version, combination of materials. When seeking to compare different manufacturers, always remember that here, too, there are no standardized measuring methods.
Depending on the field of application, the efficiency of planetary gears is also to be specified. The gearing efficiency only takes account of the rolling motion of the gearwheel, the gear efficiency of all losses of the entire bearing. It is inevitably lower than the gearing efficiency. As there are no standardized measuring methods, a comparison of the efficiency levels of different manufacturers always requires special attention. Please contact us if you have any special requirements here.
Which Temperature Ranges Can Planetary Gears Be Used in?
The application resp. operating temperature range of planetary gears depends on the respective application but also on the material and lubrication. Our pure metal versions with standard lubrication range between −30° and +120° C, the PK-series made of plastic between −15° and +65° C.
Which Protection Classes Do Planetary Gears Have?
The protection classes of planetary gears are defined according to DIN EN 60529. Planetary gears (short: PLGs) from IMS Gear can fulfil the following protection classes:
- Gears with sintered bearings: IP 40
- Gears with ball bearings (2 RS): IP 53
Upon request you can obtain output and motor gaskets to realize higher protection classes.
Which Installation Position Is Possible for Planetary Gears?
Due to grease lubrication the IMS Gear planetary gears can be installed in any desired position. In vertically arranged outputs, additional sealing measures can be provided on request.
What Is the Service Life of Planetary Gears?
Depending on environmental conditions and the operating data of the drive system, the service life of a planetary gear ranges between 200 and 30,000 hours. The great variety of application options precludes any generally applicable forecast of service life.
Planetary gears from IMS Gear are usually lubricated with grease and therefore maintenance-free during their service life. Depending on the requirements profile, we select the optimum lubricant from more than ten options.
The structural conversion through the hardening of the individual metal parts has a positive effect on the strength and wear behavior. IMS Gear has its own heat treatment shop. As the entire metal manufacturing is in-house, we can choose from various steels for hardening.
How Noisy Are Planetary Gears?
Low-noise behavior is a decisive criterion for certain applications of planetary gears. In these cases, so-called low-noise planetary gears are the solution of choice. To achieve an optimum noise behavior, increased demands on concentricity and axial run-out of the motor end plate, flange and shaft need to be met. Axial forces act on the motor shaft due to helical gearing. Sufficient dimensioning of the motor shaft bearings should be taken into account here.
To counteract the grease-promoting effect of helical gears, radial shaft sealing rings or sealed motor bearings can be used. Especially in the field of low-noise planetary gears we from IMS Gear have developed extensive experience and are available as a reliable manufacturer and development partner.