- Choice of motor and gearbox for the gate
- What available tools can be used in work
- Rack and pinion drive assembly
- Mounting the engine and transmission mechanism
- Fastening the chain to the gate
- Eliminating some chain drive problems
- Drive roller transmission
- Mechanism design
- Pinch roller accessories
- Roller-motor connection
Sliding gates are very convenient to use, but they can be improved by equipping them with an electric drive. This article will focus on the options for the drive device, the selection of suitable mechanism parts and the assembly features of functional and reliable mechanics..
A mechanized electric drive will open your gate at the touch of a button. It can be assembled from scrap materials, but installation takes no more than one day. There are two options for sliding gates. In both cases, the asynchronous electric motor acts as a source of thrust, but only in the first case, the transmission of force is performed by an asterisk and a chain, and in the second, using a pressure roller.
Choice of motor and gearbox for the gate
If the section is supplied with three-phase voltage, use a three-phase motor with a star connection. This will eliminate possible starting problems and maximize engine power..
If three-phase voltage is not available, a single-phase capacitor motor will have to be used.
Note:such a choice can result in a serious lack of starting torque.
Choose an operator in the power range of 1.2–2.5 kW, depending on the door leaf weight. It is better to choose the lowest speed possible, for example 6-pole or 12-pole motors with speeds of 1000 and 500 rpm are perfect, respectively. Low torque is needed to avoid high gear ratios and reduce the load on the drive shaft. Suitable for installation are three-phase electric motors of the A100L8 series or single-phase capacitor motors, such as AIRE 80. The cost of both options will not exceed 5,000 rubles.
The rotational speed of the drive wheel, depending on its diameter, should be 80–100 rpm. This value should be taken as the gearbox output torque. The input torque must be equal to the engine speed. Single-stage worm gearboxes are recommended for this kinetic design. The average cost of such a mechanism is 3,500-5,000 rubles.
What available tools can be used in work
You can replace some of the parts with cheaper analogs if you are sure that you can reliably connect the elements of the kinematic diagram. For example, an engine from an old washing machine can be used as a power unit. In this case, when connecting the motor, it will be necessary to determine the ends of two pairs of windings. This is done using a multimeter in the resistance measurement mode, which is much higher at the starting winding..
The shaft of the motor and the gearbox must be connected with a rigid or semi-rigid coupling. The first is a sleeve with holes of different diameters and keyways. Semi-rigid coupling is assembled from two flanges, which are interconnected by rubber petals.
Instead of a gearbox, you can use a belt drive. To correctly determine the gear ratio, divide the diameter of the larger pulley, rigidly and coaxially connected to the drive wheel, by the diameter of the smaller one, which is attached to the motor shaft.
This option implies certain difficulties in assembling the bed for fixing the elements of the kinematic diagram. For example, there are difficulties in constructing a belt tensioner. They can be partially avoided by using an automotive timing belt tensioner. Also, when using a belt drive, you will have to pay attention to the device of an independent shaft with two radial-axial bearings. The shaft must be correctly centered, because it contains the elements of two transmissions: the drive wheel and the driven belt pulley.
Rack and pinion drive assembly
The most common way to transfer power from the motor to the gate is with a chain. A star from a motorcycle or bicycle must be welded to the gearbox shaft. The Gall chain with the corresponding link pitch is stretched horizontally along the entire door leaf and fixed at its edges. Thus, when the sprocket rotates in one direction or another, the thrust is transmitted to the chain, which, in turn, pulls the door frame.
Mounting the engine and transmission mechanism
For the construction of the frame to which the engine and transmission mechanism will be attached, it is most reasonable to use angle steel with a shelf width of 50 mm. The frame must be rigidly attached to the concrete base.
When choosing a motor and gearbox, pay attention to such a parameter as the height of the axis of rotation. If it is not the same, then the base for the equipment will need to be made two-level.
The motor and gearbox are bolted with a self-locking nut to a flat and rigid metal support. The holes in the base must be oblong in order to be able to correctly adjust the position.
Fastening the chain to the gate
The most obvious place to attach a pull rod or chain might seem to be the rail. This is a common mistake, as the power transmission is susceptible to heavy contamination with this arrangement, not to mention the problem of snow accumulation. It is better to install an additional drive beam on the door leaf, keeping a height of 60–100 cm from the road surface. Attach a chain or a toothed rack to this beam from below, protected by a side casing made of rubber or plastic. The ends of the chain are fastened to the gate by welding.
Eliminating some chain drive problems
This method of transmission is fraught with difficulties. For example, the chain tends to stretch, especially under such significant loads. This effect can be eliminated by weld the studs to the last link of the chain and pass them through the eyes fixed to the door frame. This tensioner allows you to periodically select the “weak link” and tighten the chain. It is also possible to place a damping roller with a stiff spring on the drive frame, which will not only compensate for the chain sagging, but also prevent it from jumping off the star due to the so-called “dancing”.
All these difficulties can be avoided by using a rack with teeth instead of a chain. It is unlikely that it will be possible to make one with your own hands; the services of a locksmith will be required.
Drive roller transmission
There is an alternative type of gate operator that uses a pressure roller. Such a mechanism will be somewhat more difficult to design with your own hands, but at the same time, it does not require the placement of additional devices on the gate, it is not afraid of pollution, snow and ice formation.
The essence of the method is simple: a roller with a molded elastic rubber tire is pressed against the outer wall of the rail. The profile of the tire should be straight with no tread to provide maximum grip. The force is provided by a powerful compression spring. It is located on the pusher pin and is pressed with a locked nut and washer. Shaft axles are attached to the shelves of the U-shaped bracket.
To compensate for the force exerted by the roller on the door leaf, two of the same counter-rollers are installed on the opposite side of the rail, but fixed permanently.
Pinch roller accessories
Find suitable castors which can be ordered from the industrial trolley accessories catalog. Choose wheels with a metal base and sealed roller bearings that do not require maintenance. The permissible load must be 300–360 kg. It is also important to select the correct spring for the follower. Their total clamping force should be at least 3.5-4 kN, but not more than the bearing capacity of the wheels.
Choosing a way to transfer rotation to the roller. You can use a V-belt drive for this by securing the driven pulley to the metal base of the wheel with three M12 studs. It also makes sense to use a pair of open gears if you can secure them. The roller can also be fixed directly to the shaft of the gearbox or motor, after removing the bearings from the wheel base. In this case, the tensioning mechanism should not act on the axial shaft of the roller, but on the base of the gearbox housing, which is freely fixed in the longitudinal slots of the bed. Also, do not forget about the permissible radial load on the front bearing of the gearbox – it should not be less than the clamping force of the springs.
After the drive is installed, it is necessary to connect the motor, assemble and configure the starting equipment, which you will learn about from the following articles.