月: 2023年1月

What Is a Hydraulic Chuck?

A hydraulic chuck, or power chuck, employs hydraulic pressure to secure a workpiece or tool. Its hollow design often features a through-hole for bar-shaped workpieces, making it suitable for high-precision machining.

Uses of Hydraulic Chucks

Mounted on machine tools like lathes and milling machines, hydraulic chucks are instrumental in securing workpieces for operations such as milling, drilling, and burnishing. Their ability to maintain stability at high speeds makes them indispensable for precise machining tasks.

Principle of Hydraulic Chucks

Utilizing Pascal’s Principle, hydraulic chucks distribute hydraulic pressure evenly to generate significant clamping force. This principle allows for efficient force transmission, enhancing the chuck‘s gripping power.

Types of Hydraulic Chucks

Hydraulic chucks for workpieces come in various jaw configurations, including 2-jaw, 3-jaw, and 4-jaw types, each suited to different shapes and sizes of workpieces. Specialized chucks like collet types and indexing chucks offer additional functionality for specific applications.

Tool-holding hydraulic chucks are designed for securing tools with high precision. They are available in standard, high-rigidity, and slim profiles to accommodate various machining needs.

Other Information on Hydraulic Chucks

1. Clamping of Workpiece

Workpiece clamping hydraulic chucks use a rotating cylinder to apply hydraulic pressure to the jaws, converting axial force into radial force for secure clamping. Features like through-holes for bar workpieces and proximity switches for jaw position and pressure monitoring enhance their versatility and safety.

2. Tool Clamping

Hydraulic chucks for tools provide high-precision clamping with minimal runout, ensuring stable machining accuracy and extended tool life. Their sealed design negates the need for oil replenishment, simplifying maintenance.

What Is a Hydraulic Vise?

A hydraulic vise is a tool that uses the power of hydraulic pressure to strongly secure an object.

The distance between two vises can be adjusted externally by turning a handle, and the strength of the vise to hold the object changes according to the distance between the two vices.

Because it uses hydraulic pressure, it can achieve tightening precision which is difficult to achieve with manual clamping alone, and it can be strongly secured with little force.

When the clamping force is strong, one side of the clamp may lift up, causing the object to move.

To prevent this phenomenon, a hydraulic vise with an anti-lift mechanism is used.

Uses of Hydraulic Vises

Hydraulic vises are used for metal or wood processing where the material needs to be strongly secured.

This includes cutting, welding, or grinding of the material to be secured.

Although a normal manual vise can be used, it is necessary to avoid moving the position of the vise when a heavier material needs to be secured more strongly or when machining accuracy is required.

In such situations, hydraulic vises are used to secure the material.

Principle of Hydraulic Vises

A vise is a tool that holds an object between two metal plates and fixes it strongly in place.

Hydraulic vises are vises that use the power of hydraulic pressure and can clamp materials with light force. Usually, the handle is turned from the outside, and the tightening strength can be adjusted according to the amount of rotation.

This method is based on a hydraulic pressure-generating mechanism based on Pascal’s principle.

If a liquid is enclosed in a container and pressure is applied to the liquid from one side, the pressure propagates uniformly through the container.

Since the larger the area of ​​pressure, the greater the force, even if a piston with a small area is pushed in, a large force can be applied in a large area at output.

There are two types of hydraulic pressure propagators: the “built-in hydraulic pressure type” in which oil is held inside, and the “external supply type” in which oil is injected externally.

The built-in hydraulic type has the advantage that it does not require hydraulic adjustment and can be used immediately.

On the other hand, the externally supplied type is selected when the hydraulic mechanism is not required to work or when the strength of the hydraulic pressure needs to be adjusted.

What Is a Hydraulic Hose?

A hydraulic hose is a hose that serves as a flow path for hydraulic fluid in hydraulically powered equipment.

Hydraulic power is the power generated by a hydraulic pump that converts power from an engine or motor. It is mainly used in construction equipment because even a small pump can generate a large amount of power.

Unlike water hoses, they are designed to withstand higher pressures than those of ordinary household water supply systems. In recent years, hydraulic hoses are increasingly being used as an alternative to conventional hydraulic piping, such as steel pipes and rigid pipes.

Uses of Hydraulic Hoses

As an essential product for hydraulic equipment and flexible piping that can be used in high-pressure environments, hydraulic hoses are used in construction equipment such as hydraulic excavators and wheel loaders, and in factory equipment such as injection molding machines and die-casting machines.

Comparing hydraulic hose with hydraulic piping, hydraulic hose is more flexible and lightweight, and therefore has a higher degree of freedom.

Principle of Hydraulic Hoses

Hydraulic hose is used as the hydraulic oil flow path for hydraulic power and is made of thicker rubber hose compared to the water hose used in ordinary households. Hydraulic pipes used as flow paths for hydraulic power are subject to fatigue failure, such as cracking, due to vibration caused by the rotation of hydraulic pumps. Maintenance is also difficult in such cases.

Hydraulic hoses, on the other hand, are easier to maintain than hydraulic pipes. In recent years, hoses that can withstand high loads have been produced, depending on the application and type of use, and hydraulic hose is increasingly replacing hydraulic pipe.

How to Select Hydraulic Hoses

The following are the six minimum items that must be checked when selecting a hydraulic hose:

1. Confirm the type of fluid used.
2. Select the inside diameter of the Hydraulic Hose based on the flow rate and velocity of the fluid to be used.
3. Check the maximum working pressure.
4. Check the temperature and ambient temperature of the fluid to be used.
5. Check the minimum bending radius of the Hydraulic Hose after confirming its installation position.
6. Check the type of fittings

Incorrect selection of hydraulic hose can cause problems such as damage to the hydraulic hose and the inability of the machine to perform at its full capacity. To select the right Hydraulic Hose, it is necessary to have extensive knowledge of fluids, fittings, and hydraulic equipment.

Other Information on Hydraulic Hoses

1. Fittings

A hydraulic hose is subjected to high pressure loads, so it is common to use special fittings for joints with hydraulic equipment. The role of the fitting is to prevent the hydraulic hose from disconnecting due to the high pressure of hydraulic pressure.

For example, taking water pressure as an example, when a hose is connected to a faucet to let out water, if the faucet is turned fully open and water is let out under high water pressure, the holding force of the hose will be outmatched by the force of the hose and faucet to let out water, causing the hose to disconnect. To prevent this, the faucet and hose should be banded or wired together.

Since hydraulic pressure is higher than that of water, the nipple and socket of a fitting are combined to make it structurally stronger. Advantages of fitting fittings include easy connection and disconnection, no need for seals, etc. as they can be combined as a single unit, and flexible piping as the angle can be freely adjusted by the degree of tightening.

2. Installation and Maintenance

Hydraulic hoses are flexible and are often attached to moving parts. The design must take into account the possibility of damage due to contact with the peripheral equipment of the machine. Since the hydraulic oil flowing inside the hose is under high pressure, if the hose is damaged, the hydraulic oil will be sprayed out at high pressure. Since it is very dangerous for workers to be exposed to high-pressure oil, hydraulic hoses should be protected as necessary.

Hydraulic hoses are mainly made of rubber, and it is generally recommended to replace them once every two years to prevent damage due to deterioration.

What Is a Hydraulic Tool?

Hydraulic tools are powered devices that operate using a hydraulic system to generate high pressure for mechanical tasks.

These tools can be manual or electric. Manual hydraulic tools are operated by hand to generate pressure without needing an external power source, making them ideal for use outdoors or in remote locations. Electric hydraulic tools use an electric motor to drive the pump, offering faster operation and efficiency. Features like automatic pressure control and leak prevention enhance safety and performance.

Uses of Hydraulic Tools

Hydraulic tools are employed in various applications, including lifting heavy objects with hydraulic jacks and lifters, cutting and drilling metal, bending and compressing materials, crimping wiring, and piping, and more. They play crucial roles in construction, railway maintenance, underground piping, maritime operations, and automotive repair.

Characteristics of Hydraulic Tools

Advantages

Hydraulic tools boast efficiency, generating substantial force with minimal effort through a hydraulic cylinder. Their ability to precisely adjust pressure allows for controlled operation, while the liquid medium in the hydraulic system minimizes wear and tear, ensuring longevity and reliability. Their simplicity reduces the likelihood of breakdowns, making hydraulic tools both economical and productive.

Disadvantages

However, hydraulic tools can experience oil leaks and contamination, necessitating regular maintenance. The cost of upkeep can be significant due to the complexity of the hydraulic system.

Types of Hydraulic Tools

Hydraulic tools vary in their design and application, including:

1. Pump Type Hydraulic Tool

These tools manually generate hydraulic pressure and are suited for outdoor tasks. They are less ideal for high-speed operations due to the manual effort required.

2. Cylinder Type Hydraulic Tool

Using a hydraulic cylinder, these tools can perform high-speed and precise work. They may be powered manually or electrically.

3. Power Unit Type Hydraulic Tool

These tools rely on an electric pump to quickly generate hydraulic pressure, suited for tasks requiring high-volume work. While they offer enhanced safety features, they depend on an external power source, limiting their mobility.

Structure of Hydraulic Tools

Hydraulic tools operate through a process that includes generating hydraulic pressure via a hydraulic pump, actuating a hydraulic cylinder, and controlling the pressure to adjust the tool’s operation. This system ensures efficient power use and control over the tool’s movements.

Other Information on Hydraulic Tools

Common hydraulic tools and their applications include hydraulic jacks for lifting, hydraulic benders for shaping metal, hydraulic punches for creating holes, and many others, each designed to perform specific tasks efficiently and effectively.

What Is an Oil Stone?

An oil stone is a stone that is soaked in oil to be used for grinding metals and other materials.

The whetstone used in ordinary households is a water whetstone, which is used to grind kitchen knives by dipping them in water. Unlike water whetstone, oil whetstone is used to grind knives and other metals with oil.

In recent years, synthetic oils specially designed for oil stone have been sold, but in the past, kerosene was used for grinding.

Uses of Oil Stones

Oil stones are still commonly used in the United States and other countries in recent years.

In the Middle East and inland areas of the United States, water is more expensive than oil. Therefore, oil stones, which can sharpen knives without the use of water, have become the mainstream.

Oil stones are generally used in industrial applications because they are harder than water stones and wear less easily.

Principle of Oil Stones

Since oil is more lubricious than water, oil stones are made of hard, rough materials.

Water stones are made up of a collection of hard minerals, the same as oil stones. For metals with a rough surface finish, use a coarse-grained grindstone, and for finer-grained surfaces, use a fine-grained grindstone. However, the finer the grain size, the shorter the life of the wheel. Therefore, the wheel should be selected according to the required surface roughness.

There are also standards for the grain size of oil stones, which are numbered according to the average grain size. The rougher the grain size, the smaller the number, and the finer the grain size, the larger the number.

Oil stones come in a variety of shapes. The most commonly used shape is rectangular, but there are also paper-shaped grinding stones similar to sandpaper and cylindrical grinding stones.

What Is an Electroluminescent (EL) Display?

An EL display is a new energy-saving, high-luminance display that utilizes organic electroluminescence (EL) technology.

Organic compounds such as diamine and anthracene are molecules that emit light when a voltage is applied. OLED functionality utilizes this property.

Unlike conventional LCDs, OLEDs do not require a backlight, making the display thinner.

OLEDs also have the advantage of being able to display a wider variety of colors than when inorganic phosphors are used.

Uses of EL Displays

EL displays are used in a variety of situations as a new technology to replace conventional LCDs.

The most notable application is in TV displays, which are thin and have high brightness.

Other applications include smartphone displays. The thinness of OLED displays has led to the application of bendable display technology, which was not possible in the past, and as a result, smartphones with new performance and shapes are being commercialized.

Principle of EL Displays

EL Display is a phenomenon in which light is emitted when voltage is applied to organic compounds such as diamine and anthracene.

EL display is a generic term for displays that use this type of EL technology and have the advantages of high luminosity even with low power consumption and of being thinner than conventional LCDs.

Since liquid crystal is a non-luminescent material, it must be backlit from the back to emit light, a factor that hinders thinner displays.

In addition, a color filter is installed in each pixel for color display. On the other hand, EL displays are self-luminescent material that does not require a backlight and can emit light only by applying voltage, which is advantageous for realizing thin displays.

A transparent electrode is used on the side that emits light to the outside, and a reflective electrode is used on the opposite side with the light-emitting layer in between.

Using the transparent electrode as the cathode and the reflective electrode as the anode, a negative voltage is applied to the cathode and a positive voltage to the anode, enabling the injection of electrons from the cathode into the electron injection transport layer and holes from the anode into the hole injection transport layer, respectively.

When the injected electrons and holes reach the light-emitting layer, carrier (electrons and holes) recombination occurs, and the electronic energy levels of the OLED molecules in the emitting layer transition from the ground state to the excited state.

The light-emitting phenomenon derived from this energy is electroluminescence (EL), and this technology, which uses organic compounds as light-emitting materials, is called organic EL or OLED (organic light-emitting diode).

For color display, there are two types of methods: one that uses red (R)/green (G)/blue (B) light-emitting materials in the light-emitting layer of each pixel (three-color light-emitting method) and another that combines a color filter with a colorless (white) light-emitting layer (white + color filter method), as in liquid crystal displays.

In terms of power consumption and response time, they offer significant advantages over conventional LCDs.

In this way, it is now being incorporated as a fundamental technology for a wide variety of displays, including not only flat-panel TVs but also smartphones.

What Is a Metal Melting Furnace?

A metal melting furnace is designed for heating and melting various metals, facilitating processes like casting and alloying. They accommodate a wide range of metals, including iron, steel, copper, and aluminum, through different heating methods such as electric, induction, and gas heating.

These furnaces are classified into side charge and top charge types and can be stationary or tiltable, catering to different industrial needs.

Uses of Metal Melting Furnaces

Used primarily in the metalworking industry, metal melting furnaces process raw metals into liquid form for manufacturing components and products. They are essential for producing high-quality metals with specific properties tailored to various applications.

Principle of Metal Melting Furnaces

Metal melting furnaces operate by melting raw materials, and adjusting their composition through processes like degassing and filtration, to produce high-quality molten metal. These furnaces employ several heating methods to achieve the desired melting conditions.

1. Electric Heating

Utilizes electric current to generate Joule heat, melting conductive materials efficiently.

2. Induction Heating

Generates heat within the metal itself through electromagnetic induction, leading to rapid and efficient melting.

3. Arc Discharge Heating

Employs arc discharge to heat and melt materials, using high-frequency arcs to maintain efficiency.

4. Optical Heating

Focuses light, such as infrared, at specific points to heat and melt materials.

5. Gas Heating

Heats materials using combustion gases, though the gas flow can impact the process’s efficiency.

Other Information on Metal Melting Furnaces

1. Features of Induction Furnace

Induction furnaces stand out for their efficiency, reduced emissions, and rapid melting capabilities, offering a cleaner and more environmentally friendly option.

2. Aluminum Melting Furnace

Specialized for melting aluminum, these furnaces offer precise temperature control and energy efficiency, available in various designs to suit different operational scales and requirements.

What Is a Seismograph?

A seismograph is an instrument developed to record the seismic activity of an earthquake.

It is believed that the prototype already existed in China over 1,800 years ago, and is often referred to as the world’s oldest seismograph. The modern seismometer is said to have been invented in Japan in the late 1800s, which has gone under major improvements since then.

A similar term to seismograph is seismic intensity meter, which is a type of seismograph. A seismic intensity meter has the function of calculating seismic intensity in addition to the function of a seismometer, so the name is used to distinguish it from a seismometer.

Uses of Seismographs

The data measured by seismographs are used for various earthquake countermeasures.

Seismographs are also used as instruments to observe volcanic activity.

Principle of Seismographs

Figure 1. Principle of a seismograph

Seismographs are instruments that use the principle of a pendulum.

1. Securing a Fixed Point by the Law of Inertia

Figure 2. Observation of three-way swaying

Since seismographs are usually installed on the ground surface or underground and move with the ground when it shakes, a reference point, called a fixed point, is necessary to ensure that the seismographs will never move in relation to the ground.

Assuming that the fulcrum of the pendulum is the ground, a pen is placed at the position of the weight, and a roll of paper fed at a constant speed is placed at its end. If the ground shakes quickly, the entire device will shake, but the weight remains stationary in space due to the law of inertia, so the ground shaking is recorded on the roll of paper. Earthquake shaking usually occurs in all directions, but shaking parallel to the movement of the paper rolls is difficult to record, three seismographs are used, each recording the three components of north-south, east-west, and vertical directions.

Recently, seismographs that record the movement of a pendulum as an electrical signal using a coil and magnet instead of a paper roll are also utilized.

2. Observation of Displacement, Velocity, and Acceleration

Figure 3. Relationship between the natural period of the pendulum and the period of swaying

The observation of displacement, velocity, or acceleration of the ground is related to the natural period of the pendulum.

The time required for the weight to return to its original position when the pendulum swings freely is called the natural period. If the period of swing of the ground is very short compared to the eigen period, the weight will remain stationary. On the other hand, if the period of swing of the ground is very long compared to the eigen period, the weight will swing just like the ground. If the period of ground shaking coincides with the natural period, the weight will shake much more than the ground because of resonance.

A damper is installed on the weight to prevent resonance, and a response curve of seismographs is considered with the period of the ground on the horizontal axis and the displacement on the vertical axis.

In a region where the period of shaking is much shorter than the natural period and the displacement is constant, the weights are stationary in space. Therefore, it is possible to observe how much the ground has moved from its original position due to shaking, in other words, the displacement.

In a region where the period of shaking is equal to the natural period, the velocity can be observed, and in a region where the period is longer than the natural period, the acceleration can be observed.

Other Information on Seismographs

1. Types of Seismographs

There are three main types of seismographs: high-sensitivity seismographs for small tremors, broadband seismographs for slow tremors, and strong seismographs for strong tremors.

These are used appropriately for different purposes. For example, a high-sensitivity seismograph, due to its characteristics, may detect tremors that have nothing to do with the intended purpose, so measures such as drilling observation wells may be necessary.

2. Observation Method Using Seismographs

There are two types of seismic observation: regular observation and temporary observation.

Regular observation is a method of continuous observation over a long period of time, while temporary observation is a method of limited observation over a short period of time. Temporary observations are conducted for specific purposes, such as aftershock observations after a major earthquake.

3. Using Seismographs

Seismographs are used in various efforts for disaster prevention and mitigation.