Every man should have in his arsenal such a device as a screwdriver. It allows you to perform a variety of repair and construction work. However, with all the popularity of the screwdriver, not everyone knows about its device. In fact, there are not so many elements installed here. The device screwdriver following: planetary gearbox, DC motor, load limiter, battery, button speed control. On this list of devices you can finish. In fact, there may be more, but the standard equipment always includes only these five types.
Scheme of the device cordless screwdriver.
This is the main node in the screwdriver. The execution is mostly standard. The DC motor is a cylinder within which magnets are arranged in a circle. The anchor of this motor is held on special supports, which are most often made of brass. In the grooves of this anchor fit the motor windings, which are made of a material having a high magnetic permeability. The material of the armature body itself is steel. Through an equal number of turns, the winding has access to the collector plates. Engine brushes, which are made mostly of graphite and metal, touch the surface of the armature in its tail.
Types of cartridges for the screwdriver.
In order that fixing was reliable, it is necessary to press brushes. They have a special mechanism. For clamping used spring-loaded plate. They allow structural elements not to leave their rightful place, but at the same time they can move along their vertical axis. This greatly reduces wear on the mechanism. If you look at the diagram of a permanent motor, you can find that the voltage is supplied exclusively on the brushes themselves. In this case, the direction of rotation of the motor is directly dependent on the polarity of the applied voltage.
Naturally, this is a primitive device, but this knowledge is quite enough to make regular repairs to the motor. Most often in it windings fail. They can simply burn from overloads, so you should always ensure that the equipment does not work at the limit.Back to table of contents
Planetary gearbox: features
Device network screwdriver.
This is another very important mechanism in the work of the screwdriver. It is always made in a separate case. This mechanism consists of the following parts: sun gear, ring gear, satellites and carrier. Only four components which can fail as a result of operation. Most often, low-cost screwdrivers consist of gearbox elements that are made of plastic. More expensive models are made of metal. The second option is preferable, since only it allows you to save the tool for many years in operation.
Not all gears are made the same. Each manufacturer has its own secrets of craftsmanship. In order to repair a node, it is necessary to specify the location of each individual element in accordance with the scheme.
The ring gear is considered the main part. It has a cylindrical shape. Along its circumference are the teeth, along which the satellites move. They are mounted on the carrier pins. The sun gear is located between the satellites of the first carrier.
The first carrier on the opposite end has a second sun gear.
Screwdriver gear unit.
It, of course, is attached to the second carrier. As is clear, the device is quite simple, if not to say that it is primitive. Such a planetary gearbox is taken as a basis by manufacturers, as it is reliable and has simple assembly. When repairing, you can troubleshoot on your own.
If we are talking about a gearbox, which has two stages, then the second carrier is attached to the shaft rigidly. This refers to the shaft on which the cartridge is mounted. It turns out a kind of sandwich, which consists of two drivers and satellites. This whole mechanism is located inside the main gear. It is worth noting the fact that the ring gear itself is fixed rigidly in the housing. To do this, you can use special latches or protrusions that are located on the sides. The protrusions at the same time abut the special balls, which are located around the circumference. They, in turn, are set on an elastic ring.
The ring is always spring loaded using a load limiting mechanism. The spring force can always vary due to the load that acts on the device. Each planetary gearbox has a simple structure, which does not affect the course of its operation. As you know, everyone can repair the mechanism with their own hands. It requires only a little skill and knowledge of plumbing. This is a great solution for the screwdriver has been developed for a long time. Previously, other gearboxes were used, but in the end, almost all manufacturers switched to a planetary version of the mechanism that allows the screwdriver to work in almost any conditions without any significant overloads.
Scheme of the internal device screwdriver.
It is worth talking about the work of the mechanism itself. The sun gear in it drives all the satellites around the ring main gear. The result is a phenomenon where the carrier rotates at a much lower speed than the engine itself. Since the second carrier is even higher relative to the axis of rotation, respectively, when transmitting torque from the first structural element to it, the speed becomes much lower. This is the principle of the two-stage gearbox. Today they are very popular among manufacturers and buyers. The ability to adjust the speed always allowed to bring work to a completely new progressive level. Of course, there are more complex mechanisms that have three gear shift stages. In this case, the speed adjustment is carried out through the use of an additional planetary gear.
In order to work as efficiently as possible, some models presented on the market have double-sided gearboxes. The first speed is used to tighten the screws themselves, and the second - for drilling holes. This is a great solution, which every year becomes more and more popular. For repair and construction work on a large scale it is worth acquiring just such a tool.Back to table of contents
Speed controller: the nuances
Possibilities of household screwdrivers.
The speed control is also done in a very simple way. Here, a pulse-width controller and a key, which is made on the basis of a field-effect transistor, are involved. As for the control, it uses a variable resistor. Its resistance, and, accordingly, the speed of rotation, directly depend on the force pressing the power button. It is sometimes called the trigger. The reverse affects only the direction of the voltage applied to the engine. Here for these purposes apply special flip contacts. The whole process is automated, so a person doesn’t have to do anything manually.Back to table of contents
Battery and its characteristics
Without a battery simply can not do. It serves to supply the DC power to the motor. The battery is also installed small-sized. This allows to significantly reduce its weight for ease of operation. It represents such a device at once several feeding elements fastened together, which are connected in series.
At the same time, they all come together in a single building, so they are presented to a person as a whole. The range of supply voltage at the screwdriver can be very diverse. It starts at 9 volts for home household models, and can reach 18 volts for powerful professional devices. Here you can put forward a direct pattern. The higher the power supply, the more powerful the screwdriver will be.
So, now everyone knows about the components of the screwdriver. As you know, they are all quite simple. Knowing the device screwdriver, you can always draw conclusions on how it can be repaired. A person who has a strong theoretical base can always put it into practice. Repairing a screwdriver with your own hands will always save a lot of money.