Assembling the gearbox of the Makita 6271d screwdriver

Principle of operation and main components

Before you start repairing a screwdriver with your own hands, you need to understand the principle of its operation and what parts it consists of. The main difference between a screwdriver and other power tools is the use of a mechanism that stops the rotation of the working part of the device. This happens when the maximum resistance for the instrument is reached. This value is not constant and can be adjusted. There are two types of device:

  • operating from a 220 volt network;
  • using a rechargeable battery.

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Regardless of the type of device, the principle of operation is the same and is based on the transmission of torque. It determines which fastening tool can screw the screwdriver. To increase the torque in the devices, gearboxes with a large gear ratio are used, but the rotation speed is reduced. With AC power screwdrivers, the torque value is related to the power consumption of the tool. The main parts that underlie the screwdriver device, be it Makita, Hitachi or Bison, are as follows:

  • electric motor;
  • push button;
  • reverse speed regulator;
  • chuck;
  • the electronic unit;
  • reducer.

The electric motor rotates the spindle at a set speed using a planetary gearbox. The torque is controlled by a coupling and a chuck or hex holder is fitted to the spindle. A removable device called a “bit” is installed in this cartridge. The screwdriver is controlled by an electronic circuit and reverse switching.

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The tool uses a planetary gearbox. The gearbox includes sun and ring gears, satellites, carrier. The shaft of the electric motor rotates the sun gear, which transmits the torque to the satellites, and they already directly act on the carrier.

The reducer is available in one- and two-stage type. In the second case, a double carrier connected to the shaft is used. The design of two carriers and satellites is located in the middle of the ring gear. It is fixed through special grooves on the body. Along the entire perimeter, the projections of the ring gear abut against the spring-loaded balls through the ring. The load regulation mechanism acts on the ring through a controlled spring, the force of which is changed by adjusting the regulator.

The speed control is performed using a pulse circuit assembled on a pulse-width modulation (PWM) microcircuit. The controller controls the field-effect transistor operating in the key mode. The pulse frequency is changed using a variable resistor. The resistance value of the resistor depends on the force applied to the button.

The screwdriver sleeve is a ratchet. If the load on the chuck exceeds the permissible value, the load regulator is triggered. The force of the spring becomes insufficient to hold the ring gear, and it comes off the balls. The electric motor starts to rotate the gear idle. When switching to electric drill mode, this gear is turned off and does not participate in the work.

A rechargeable battery with a voltage of 12 V or 18 V is most often used as a power source. It characterizes the power of the device.

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The battery consists of several elements installed in one housing and connected in series. The case has a special latch that allows you to quickly remove the battery.

Charger repair

To restore the performance of rechargeable batteries, a charger is used on the power tool. Bosch screwdrivers are no exception. One of the failures of the screwdriver is the failure of the charger.

This breakdown manifests itself as follows. The rechargeable battery is set to charge. The device turns on for literally a few minutes, and then turns off, indicating that the charging process is complete. In this case, the battery remains in a discharged state.

How to assemble Makita 12V cordless drill 6271D gear assy assemble and motor change

To find out the reason for the refusal, you must:

  • Disassemble the charger case by unscrewing 4 self-tapping screws. It consists of two sections. In the first, a transformer is installed, in the second. the control board of the device.
  • Now you need to apply voltage to the transformer and measure the current. If it matches the face value, go to the next operation.
  • As a rule, the control chip and rectifier are in good order in this case, so you need to check the power connectors while the device is operating. A thin wire must be soldered to each contact. They will make it possible to measure the voltage during the operation of the device.
  • Charging is turned on and current measurements are taken. If the readings are unstable, up to complete disappearance, then the reason is the bending of the power terminals due to prolonged operation of the device.

Restoring contact will allow you to get a full charging process.

DIY repair

In a home workshop, it is not so difficult to repair a gearbox. Repair is reduced to disassembling the unit into separate parts, checking the integrity of their structure, purging and lubricating, followed by reassembly. The process is subdivided into the following stages:

  • Separating the gearbox from the engine and removing (usually with a chuck) from the screwdriver casing.
  • Unscrewing the housing and removing the locking washer.
  • Sequential removal of satellites and transfer plates (2 or 3, depending on the design).
  • Removing the ring gear and checking the ball bearings (they can roll over the entire seal, but should not roll outside of it).

Makita DDF456 disassemble. Whats inside gear assembly

After removing all parts, they must be cleaned of “old grease”, wiped dry and make sure that they are not damaged.

Then the craftsmen recommend folding them in the reverse order “dry” and make sure that when the satellites rotate, the chuck spindle also rotates. If the rotation is carried out without scrolling, then it can be assembled back.

First, bearings are placed in the grooves in the housing, on which the annular gear is installed. Then, one at a time, put the transfer plates, with the satellites installed on them and put on top of the fixing washer.

Assembling the gearbox of the Bosch screwdriver

The history of the appearance of the device

A screwdriver is a power tool. Its main purpose, following from the name, is to twist or unscrew the fastener. After the electric drill was invented in 1868, the development of the power tool became widespread. Founding companies DeWalt, Bosch, BlackDecker, Makita and Hitachi pushed the industry forward with new devices.

The advent of the Phillips screw in 1934 created a demand for an electric tool for tightening it. It turned out to be especially in demand in mechanical engineering. The first such device was called a wrench. With the advent of batteries, the device gained mobility, and the name screwdriver came into use. Its mass production began in the early 80s.

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Modern devices are constantly being improved, but to a greater extent this relates to the method of autonomy and control. The design of the device remains unchanged.

Home workshop: how to repair a screwdriver gearbox?

Any tool, regardless of model and brand, sooner or later breaks down. A screwdriver is no exception: individual parts and assemblies wear out over time, and without proper care or under force majeure, they may refuse.

The main functional load during the operation of the tool is distributed through the gearbox between the engine and the chuck, so if something happens to the gearbox, the work will begin. In order not to spend money on repair services, it is enough to use the advice of the masters to restore the operation of the unit yourself.

Battery bank: troubleshooting

It is not difficult to identify battery damage. It is enough to measure its voltage after fully charged. The voltage on one cell is 1.3 volts. the voltage of a fully charged battery of 12 cells should correspond to 15.6-15.7 volts. If the voltage is insufficient, this is a signal for further battery check:

  • To do this, unscrew the screws on the case and take out the cassette with cans.
  • Visually inspect galvanic cells for oxidation and degradation.
  • Then you need to measure the voltage on each bank. If one or more voltage is absent, then they must be replaced immediately.
  • Armed with a soldering iron, it is necessary to remove everything that can prevent you from removing the punched can: the positive wire and the temperature sensor. It is better to insulate the power cable to avoid short circuit.
  • Now you need to disconnect the plates welded to the battery, align them for a more reliable contact.
  • After that, you need to tin the contacts. To reduce the heating time and temperature, it is advisable to use flux Ф38м. It is applied in a small amount to the contact plate and liquid solder is added. Spreading over the surface, it tinns the contact. This must be done on both sides of the upper and lower contact plates.
  • After that, you need to prepare the battery bank itself. Apply flux in the place of its contact with the contact. The plate with the heated solder must be pressed against the jar in the upper end. And the same must be done with the lower contact.
  • After that, it is necessary to restore the temperature sensor and the positive contact. Then proceed with the assembly of the repaired battery.

Repair of the charger of the Makita screwdriver

When repairing the charger, it is necessary to loosen the screws securing the housing covers. Inside there is a printed circuit board with contacts. First you need to check the transformer with a tester. To do this, you need to measure the output voltage. Then you should ring the cable to exclude its fracture. Then the primary and secondary windings of the transformer and the fuse are checked. You need to collect it in the reverse order.

Dismantling the Makita screwdriver

To disassemble the screwdriver, you need a Phillips screwdriver and some personal time. To disassemble the screwdriver completely, you need:

  • unscrew the screws securing the case;
  • remove the composite start button mechanism;
  • remove the electric motor together with the gearbox;
  • disconnect the gearbox from the engine by unscrewing the bolts that hold them together.
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To disassemble the battery of a screwdriver, you need to loosen the bolts connecting the body, or separate the body joints on an adhesive basis using a soldering iron. Inside the battery there are several nickel-cadmium batteries with a certain capacity and carrying a charge. In case of battery repair, they need to be replaced with new ones.

The chuck is changed with a screwdriver and a hex wrench. First, use a screwdriver to loosen the fixing screw in the chuck by turning it clockwise. Then the hexagon is inserted, the reverse button is turned on, it is clamped, and then the chuck easily lends itself.

“Makita” screwdriver battery repair

When repairing the battery with a Phillips screwdriver, unscrew the screws that secure the case. There are several cans inside the case. Visual inspection should be used to inspect them and identify abnormalities in geometry such as bulging, for example. We test the banks with a multimeter for residual charge. If it is absent, the bank is replaced with a new one.

Assembling the gearbox of the Makita 6271d screwdriver

In this article, we will consider a screwdriver from the well-known Makita brand, describe its technical characteristics and general device, talk about the main problems and malfunctions that arise during the operation of the tool, as well as how to diagnose a breakdown and repair one or another element with your own hands. screwdriver.

Scheme 1

The diagram shows:

  • Shift lever
  • Body assembly
  • Nameplate
  • Screw
  • Spring
  • Reverse shift lever
  • Start button
  • Contact terminal
  • Screw
  • Keyless chuck
  • Gearbox assembly
  • Electric motor
  • Screw
  • Body assembly
  • Charging unit
  • Battery

A modern screwdriver is a high-tech device. Important structural elements:

  • Removable battery
  • Rubberized handle grip
  • Powerful electric motor
  • Metal planetary gearbox
  • Soft start button
  • Reverse switch button
  • Torque regulator

These are the main components of the screwdriver design, which are included in the basic package of any screwdriver model.

Scheme 2

Repair of the button of the screwdriver “Makita”

The on / off button of the instrument is a complex electronic mechanism. It consists of several elements that make it up:

  • start buttons;
  • reverse buttons;
  • buttons for switching the speed of revolutions;
  • soft start buttons.

When repairing a button, you first need to disassemble it by unscrewing the screws that secure the case and disconnecting the battery. After that, you must check the connections and contacts for dirt, clean them. If cleaning the contacts did not help to fix the problem, the button should be replaced as a complete.

Description, general information

Makita screwdrivers are very powerful. The average stroke rate for various models is about 2300 rpm, which is a good indicator compared to other brands. The weight of most models of tools is within 1.5 kg. Its small mass means that it will be comfortable to work with such a tool. The manufacturer also took care of the convenience of working in poorly lit rooms, making LED backlighting for most models. Separately, it is worth highlighting the type of handle for holding these tools on the weight. As a rule, they are made rubberized, and therefore it is convenient to hold them in a brush, respectively, the work process is much easier.

The disadvantage of these screwdrivers is the strong vibration of the handle during operation, as well as their short-lived batteries. In addition, the price for the products of this company is quite high, which is important for the domestic consumer.