投稿者: myyn

What Is a Hydrogen Tank?

Hydrogen tanks are tanks that store hydrogen.

Hydrogen tanks are used in fuel cell vehicles powered by fuel cells. In the case of fuel cell stacks, compressed hydrogen is stored in hydrogen tanks installed in the vehicle, and hydrogen can be supplied to the fuel cell stacks.

Hydrogen tanks used in vehicles must withstand higher pressure loads than tanks for natural gas. Hydrogen tanks are made of carbon fiber reinforced plastic or other materials that have been modified to increase their pressure resistance.

Uses of Hydrogen Tanks

Hydrogen tanks are used to store hydrogen. They are installed in fuel cell vehicles and used for hydrogen storage at hydrogen stations.

Hydrogen is very light and requires a large amount of space to store in its original state. Therefore, hydrogen is stored by compressing it at high pressure, liquefying it at low temperatures, adsorbing it onto metals, or converting it into another substance.

The most commonly used storage method is to store hydrogen at high pressure in its gaseous state, which requires high-pressure hydrogen tanks.

Principle of Hydrogen Tanks

Hydrogen tanks used in fuel cell vehicles are a necessary component of a fuel cell vehicle. As a method of storing hydrogen in a fuel cell vehicle, low-pressure hydrogen tanks can easily be used to store hydrogen in gaseous form and supply fuel to Fuel Cell Stacks.

However, the tank volume must be large. The burden of infrastructure development for supplying hydrogen is lighter and is applicable to electric carts and other vehicles that are designed to store small amounts of hydrogen. High-pressure hydrogen tanks are also in practical use in mass-produced fuel cell vehicles,

This is a common method for hydrogen storage. Due to storage space limitations in hydrogen tanks, hydrogen can be compressed and stored to extend the driving range of the vehicle. When hydrogen is cooled to ultra-low temperatures, it can be liquefied and stored in liquefied hydrogen tanks.

Liquefaction greatly reduces the volume of hydrogen compared to gas, which strongly contributes to downsizing. However, temperature control is important because hydrogen vaporizes when the temperature rises.

Structure of Hydrogen Tanks

The structure of hydrogen tanks varies depending on the system.

1. High-Pressure Hydrogen Tanks

Aluminum alloys, special stainless steels, and polymer composite materials are used. Steel cannot be used for high-pressure hydrogen tanks. This is because high-pressure hydrogen enters metals such as steel, causing them to become brittle.

2. Liquefied Hydrogen Tanks

Hydrogen tanks cool hydrogen to -253°C and store it as a liquid in a double-layered container with a vacuum between the tanks. The vacuum prevents heat transfer to the outside and prevents the temperature of the hydrogen from rising.

However, it is not a perfect vacuum, and even vibration produces heat, causing some hydrogen to become a gas. It is important to research technologies to safely remove gaseous hydrogen gas and to reduce the amount of vaporization by approaching a vacuum.

3. Hydrogen Storage Alloys

Hydrogen storage alloys have been put to practical use for storage in nickel-metal hydride batteries. In addition, methods of converting hydrogen to another substance for storage, such as converting toluene to methylcyclohexane by reaction with hydrogen, have been studied in recent years.

Types of Hydrogen Tanks

There are several types of hydrogen tanks.

1. Low-Pressure Hydrogen Tanks

Hydrogen can be stored as a gas, but requires a large tank due to the low pressure. This type of tank is used to store small volumes of hydrogen.

2. High-Pressure Hydrogen Tanks

Since vehicles have limited space for tanks, more hydrogen can be stored in higher pressure tanks with the same tank volume.

3. Liquefied Hydrogen Tanks

Hydrogen tanks store liquefied hydrogen at ultra-low temperatures in insulated tanks. Liquefaction reduces the volume of hydrogen to 1/800th of gas, which is advantageous for installation in vehicles.

4. Hydrogen Storage Alloys

Since the atomic diameter of hydrogen is small, it can be stored when it is absorbed between the molecules of special alloys. When hydrogen is removed from the storage alloy, heat is applied. About 80 kg of storage alloys are needed to store 1 kg of hydrogen, making weight an issue for in-vehicle use.

Hydrogen can also be stored on the surface of carbon nanotubes and molecules with very large surface area.

5. Hybrid Type Hydrogen Tanks

A structure that combines a hydrogen storage alloy and high-pressure hydrogen tanks is used.

What Are Fuel Cell Stacks?

Fuel cell stacks are the power-generating units of a fuel cell vehicle.

Also known as a fuel cell stack, a fuel cell vehicle is called an FCV (fuel cell vehicle). Energy is mainly radiated using electricity generated when hydrogen and oxygen react to replace water.

As a result, no toxic waste gases are generated, making it one of the decarbonization technologies that has been attracting attention in recent years.

Uses of Fuel Cell Stacks

Fuel cell stacks are used to power fuel cell vehicles. By electrochemically reacting to hydrogen and oxygen in the air, an electrical output is obtained to power the vehicle.

Fuel cell stack-based fuel cell vehicles are in increasing demand due to their strong output and compact size. They are also attracting attention as a decarbonization technology toward achieving carbon neutrality.

It is a key technology for fuel cell vehicles, characterized by high energy conversion efficiency, reduced harmful emissions to the environment, low noise, and fast load response.

Principle of Fuel Cell Stacks

Fuel cell vehicles typically generate electricity with a polymer electrolyte fuel cell (PEFC). Fuel cell stacks play the role of a power generator.

Currently, hydrogen and oxygen are used as fuel cells in many fuel cell vehicles. Hydrogen is supplied to the fuel electrode and oxygen to the air electrode. In the electrolyte sandwiched between the two layers of fuel and air poles, hydrogen ions produced at the fuel electrode move toward the air electrode.

The principle is that the electrons separated at the fuel electrode then move through the electronic circuit, generating an electric current. This principle is commonly used for fuel cell stacks for vehicles, and its advantages include operation at low temperatures and high power generation efficiency, even in a small size.

By incorporating hydrogen and oxygen from the atmosphere into the fuel cell stacks installed in the vehicle, electricity is generated, and the electrical energy is used to drive the battery and motor, thereby powering the vehicle.

Structure of Fuel Cell Stacks

Fuel cell stacks are made by stacking flat cells in a stack structure, and connecting multiple cells in series to obtain the output required for the vehicle. The inside of the cell consists of three layers (fuel electrode, electrolyte, and air electrode), and although a single cell can generate electricity on its own, a number of cells are stacked in a stack structure to produce the voltage required for a fuel cell vehicle.

Since heat is generated during power generation, the stack is cooled to suppress the temperature rise during use.

Characteristics of Fuel Cell Stacks

Fuel cell stacks have several differences from conventional vehicles. They are able to provide a comfortable ride and run on less electricity because they have features that are unique to fuel cell stacks.

Other than that, one of the features is that they can run safely for a long time with a single fill, and many innovations have been made to realize these features.

1. Battery

Electricity generated by fuel cell stacks is either sent directly to the motor or stored in batteries, which are nickel-metal hydride or lithium-ion batteries, similar to electric vehicles and hybrid vehicles, which are vehicles powered by something other than gasoline.

The unique feature of the two types of batteries is that they can supply power directly to the motor, making it possible to use even less battery capacity than in an electric vehicle.

2. Cooling Water

Fuel cell stacks require dedicated cooling water. The main component is an ethylene glycol solution with excellent cooling performance and anti-freeze, and has low conductivity to prevent electric shock.

This feature reduces the risk of ignition or electric shock in the event of an accident and is therefore widely used by various manufacturers. In addition, the coolant used is divided according to the make and model of the car to ensure optimal running.

3. Environmental Friendliness

Since only water is discharged during driving, it helps reduce CO2 emissions. Since no combustion is used to generate electricity, there is no generation of nitrogen oxides.

Fuel cell stacks do not require any gasoline, which is used in many automobiles, and help solve the problem of exhaust emissions. In addition, the high efficiency of power generation allows for longer operation with shorter recharging times.

What Is Car Steering?

Steering refers to the steering system of a car. It is also called a steering wheel. By operating the steering wheel, you can control the direction of the car’s tires and change the direction of travel.

A steering wheel refers only to the handle of the steering system, while steering refers to the entire steering system, including the mechanism.

Uses of Steering 

Steering is used to change the direction in which the car is moving and is used by the driver when driving a car.

It is used to change the direction of the wheels of a car, but actually changing the direction of the wheels of a car requires a great deal of force. When the weight of a car’s wheels was originally light, the system used only the driver’s arm strength to change the wheels, but modern cars require a great deal of power to steer. For this reason, cars are often equipped with power steering systems that use hydraulic or motor power to lighten the steering wheel operation.

Principle of Car Steering

Steering a car requires an inherently large amount of force when turning the steering wheel to change the car’s direction of travel. Most of today’s cars are equipped with power steering, which assists the driver in turning the steering wheel. Power steering is a function that assists the force required to turn the steering wheel due to frictional resistance between the tires and the ground at low speeds.

In hydraulic power steering, the rotation of the engine is connected by a belt to a power steering pump, which produces hydraulic pressure to assist the steering wheel rotation.
In electric power steering, an electric motor turns the steering wheel to assist in turning the steering wheel. Electric power steering is the most common type of power steering used in automobiles today.

Hydraulic power steering has a long history of use and the technology is well established, making it inexpensive and capable of producing a large output. However, as they age, oil leaks and the hydraulic pump operate while the engine is running, which reduces fuel efficiency. Electric power steering is powered by an electric motor, making it easy to control on/off and saving space compared to hydraulic pumps.

What Is a Door Handle?

Door handles are handles for opening and closing doors.

They are also called door knobs. The function of a door handle is to open and close the door, but there are several types depending on the type of action used to open and close the door.

Examples of door handles for automotive applications include the grip type, flap type, outer door handle type, and button type. The types of door handles have evolved over time and safety considerations into several types, and continue to do so today.

Uses of Door Handles

Door handles are handles for opening and closing doors, and can be used anywhere as a switch to open and close doors by a certain action.

There are many types of in-vehicle door handles, each with different operations to open and close the door. Non-vehicular door handles include pull handles, stick handles, bar handles, lever handles, and grip balls.

Principle of Door Handles

The mechanism for opening doors with in-vehicle door handles is generally a mechanical, opening and closing. The door can be unlocked by a wiring harness inside the door.

Door handles operate differently depending on the type.

1. Grip Type

In the case of the grip type, the door is opened by grasping the door handles and pulling them forward. The grip is designed so that the hand can be inserted from either the top or bottom to hold the door handles when opening or closing the door, making it easy to open or close the door even when wearing thick gloves.

2. Flap Type

In the flap type, the door is opened by inserting the hand from the bottom and raising the plate-shaped door handles. This type requires less force than the grip type and can be easily operated even by those with limited strength. Since door handles do not protrude from the door, they are less susceptible to air resistance.

Structure of Door Handles

Door handles are available in cylindrical, lever-handle, and push-pull types.

1. Cylindrical Type

Traditional door knobs are cylindrical and have been widely used for interior doors and front doors. They are still often used today, but they must be turned by hand, and it is more effective to replace them with lever-handle types as a measure against infection. There are two types: one that is separate from the key and one that is integrated with the key.

2. Lever Handle Type

The lever handle type can be opened and closed simply by lowering the handle. This reduces the burden on the weak elderly and is suitable for barrier-free rooms. There are types with a separate key on top of the lever handle and types with the lever handle and key integrated into one unit.

3. Push-Pull Type

Push-pull type is often used for entrance doors. The door is opened by lightly pushing the Door Handles when exiting, and pulled when entering. No great force is required, and the key is attached to the top and bottom of the handle for high security.

Types of Door Handles

There are several types of door handles and materials.

1. Aluminum Handle

Aluminum is light and strong. It is soft and easy to process, and is available in a wide range of designs. It has an elegant luster and shimmers when it reflects light. It conducts heat easily and is not suitable for extremely hot or cold places.

It can be cleaned by simply wiping with water and wiping dry. If stains or rust are a concern, wipe with a diluted solution of neutral detergent or polish with a fine-grit sandpaper.

2. Iron Handle

Iron is brittle and rusts easily, but handles are made of steel alloyed with an increased amount of carbon. Steel is harder and stronger than iron and easier to work with. It is black and goes well with wooden furniture.

To clean a door handle, wipe it with a soft, dry cloth. If it gets dirty, wipe with a cloth moistened with neutral detergent and absorb the water with a dry cloth. Wax is effective in preventing rust.

3. Brass Handle

Brass is an alloy of zinc and copper. It has a beautiful luster and is also called brass. The color will fade and become astringent, but it can be polished to bring it back to luster as many times as you like. However, it is weak against water and prone to rust and discoloration.

It should be cleaned by wiping it dry with a soft cloth. If stains are a concern, wipe with neutral detergent and then dry.

What Is a Motor Core?

A motor core, as the name implies, refers to the core of a motor.

The core of the motor is the iron core, which is the pathway for the magnetic flux of the motor. The core allows magnetic fields to pass through more easily than in air and is an important element in the propagation of the magnetic flux between the primary and secondary stages.

The most commonly used material for cores is electromagnetic steel sheet, but there are various other materials such as silicon steel sheet, permalloy, ferrite, and amorphous. There are also various types of cores by shape, such as sheet cores, cut cores, R-cores, and toroidal cores.

Uses of Motor Cores

Motor cores are used in the iron core of motors. It is used in the iron core of the rotor (rotor) and stator (stator) that make up the motor.

High assembly precision is required for the rotor and stator in order to achieve motor performance. Therefore, high machining accuracy is required for the motor core.

Since motors are used in a wide variety of electronic devices that are electrically and physically driven, and since motors of various sizes are used in electronic and industrial devices, motor cores used in the iron cores of motors are also used in a great many electronic devices.

Principle of Motor Cores

As the principle of motors, taking a rotating motor as an example, it can rotate with magnets and magnetic force. When a magnet is turned around a permanent magnet with a rotating shaft, the N and S poles attract and repel each other, causing the magnet with the rotating shaft to turn. If we replace this with a situation where the magnet is driven by electricity, a magnetic field is generated around the copper wire by passing an electric current through it. This becomes a rotating magnetic field, which is the same as the environment in which a magnet rotates.

By coiling the copper wire, the magnetic force is synthesized into a magnetic flux. Also, by inserting the core into the coiled copper wire, the magnetic field lines can easily pass through the core and generate a stronger magnetic force. Motor cores are used inside motors in this way.

Motor cores are processed as laminated cores, which are made by laminating plates. The processing methods for laminated cores include the caulking method, in which multiple plates are pressed together as laminated parts, the laser welding method, in which laminated parts are welded together, and the bonding method, in which laminated parts are adhered together using adhesive.

What Is a Piston?

Pistons are one of the key components inside an engine that converts the combustion energy of fuel into mechanical power.

There are two types of engines: reciprocating engines and rotary engines. Pistons move up and down inside a cylindrical part called a cylinder to produce the engine’s power, which is the driving force that makes the car run.

Pistons are also used not only in automobile engines but also in engines for motorcycles, ships, and aircraft.

Uses of Pistons

Pistons are mainly used in engines, compressors, air compressors, and other equipment. These devices use a mechanism in which the pistons move up and down to generate power through thermodynamic changes, such as compression and expansion.

In an engine, the combustion energy of fuel is converted into mechanical power by the movement of the Pistons, and this power is transmitted to the drive wheels of the car via a component called the crankshaft. Air compressors and compressors also use the movement of pistons to compress gas and use the energy to generate power.

The number of pistons varies depending on the application, but the four-cylinder engine, which consists of four pistons, is widely used in standard passenger cars. These Pistons move back and forth inside a cylinder, which is called a cylinder, at more than 1,000 revolutions per minute. It is also called the heart of the car because it is a necessary device for generating the car’s power.

Principle of Pistons

The principle of piston movement is that, in the case of an engine, the high pressure generated by the combustion of fuel causes the pistons to move up and down inside the cylinder. This movement is accomplished by repeating four motions (intake, compression, expansion, and exhaust).

1. Intake

This is the process of drawing air and fuel into the cylinder for compression. As the pistons descend, a negative pressure is created in the cylinder and the intake valves open, bringing in a mixture of air and fuel.

2. Compression

This is the process of the pistons rising and compressing the air-fuel mixture. With the intake and exhaust valves closed, the rising pistons compress the air-fuel mixture in the cylinder and raise its temperature.

3. Expansion (Combustion)

This is the process in which the spark plug sparks the compressed air mixture and causes it to burn. The hot, high-pressure gas generated by the combustion exerts a downward force on the Pistons, causing them to move downward. This movement generates power in the engine.

4. Exhaust

This is the process of exhausting the exhaust gases from the cylinder after combustion. The pistons rise again and the exhaust valves open to expel the post-combustion gases out of the cylinder.

The repetition of these processes causes the pistons to move up and down, producing power from the engine.

Structure of Pistons

Pistons are generally cylindrical metal parts, made primarily of materials such as aluminum alloys and cast iron. The main components of pistons are as follows:

Pistons are the heart of an engine, and their performance and durability greatly affect the performance and fuel economy of an automobile, so proper maintenance and replacement of parts is important.

1. Pistons Head

The piston head is the part of the cylinder where combustion takes place. It has a sturdy structure to withstand the pressure of the compressed air mixture and combustion gases.

2. Piston Rings

They fill the gap between the pistons and the cylinder, preventing gas leakage and ensuring proper distribution of lubricating oil. There are usually two types: compression rings and oil rings.

3. Piston Skirt

Located at the bottom of the pistons, it serves to support the steady movement of the pistons within the cylinder.

4. Piston Pins

The pistons are connected to the connecting rods (the parts that connect the crankshaft to the pistons) and transmit the movement of the pistons to the crankshaft.

What Is an Oil Cooler?

Oil coolers are devices used to cool and maintain the oil used in car engine oil and industrial machinery at the proper temperature.

It is also called a radiator in cars and motorcycles, and in a broader sense, a heat exchanger. The viscosity of oil can change, depending on its temperature. Since viscosity greatly affects oil performance, the oil must be kept at the temperature at which it performs best.

Oil Coolers are responsible for cooling the oil to keep it at the proper temperature.

Uses of Oil Coolers

Oil coolers are used in automobiles and motorcycles. In the case of automobiles, oil coolers are used in radiators to cool the engine oil and in automatic transmissions such as A/Ts and CVTs to cool the ATF and CVTF.

In FF A/Ts and CVTs, built-in coolers that can be directly installed in the transmission itself are often used. Other applications include construction machinery, industrial machinery, and agricultural machinery.

Principle of Oil Coolers

There are two main types of oil coolers:

1. Water-Cooled Oil Coolers

Water-cooled oil coolers are widely used in automobiles. Oil coolers, which cool the engine oil, are usually called radiators. The engine oil is cooled by the power of coolant called coolant.

The way it works is that the engine oil passes through the cooler core, which is covered by a water jacket through which the coolant circulates. Basically, the lower limit of the cooling temperature is the same as that of the cooling water, so the engine oil temperature is stable regardless of the outside temperature.

2. Air-Cooled Oil Coolers

Air-cooled oil coolers release heat by airflow. The heat is transferred to the oil coolers themselves as the hot oil passes through the oil coolers.

Oil coolers for stationary industrial machines are made of metals with high thermal conductivity, such as brass or brass, and have many fins on the surface. By increasing the surface area with fins, the amount of heat that can be dissipated is increased.

Other Information on Oil Coolers

1. Benefits of Oil Coolers

The primary role of oil coolers is to keep the engine oil at the proper temperature. Engine oil is formulated to perform best at temperatures between 80-100℃.

Cooling the engine oil with oil coolers provides a variety of benefits. The most important effect is to maintain lubricity. Automobiles are made up of a combination of various metal parts such as gears, bearings, and sliding bearings called bushings.

Also, in an engine, the piston slides through the piston chamber. To reduce friction between these parts, oil is essential. By keeping the temperature of the oil in the proper range with oil coolers, the sliding resistance between parts is reduced and the machine can continue to operate normally.

Especially in the case of engines, as output increases, heat from exhaust gases, combustion chambers, and cylinder walls causes the engine oil temperature to rise. Therefore, the temperature is regulated using the power of cooling water. Note that water-cooled oil coolers can prevent the engine oil temperature from dropping too low compared to other oil coolers. This is because the coolant never gets lower than room temperature.

2. Performance Requirements for Oil Coolers

While sufficient cooling capacity is required for automotive oil coolers, there are various other requirements. First, they must be compact and lightweight. Since automobiles are required to have a large occupant space, components that fit inside the engine compartment must always be compact. Lightweight is also an important requirement in terms of fuel efficiency.

Another requirement is that the oil flow resistance must not be too large. If the oil flow resistance is too large, the amount of oil circulating will be reduced and the cooling capacity will also decrease. Also, in a low-temperature environment, the oil needs to warm up quickly. To warm up the oil quickly at low temperatures, it can be said that oil flow resistance is an important requirement.

What Is a Head-Up Display?

Head-up displays are displays located in front of the windshield or instrument hood.

It is characterized by its ability to project vehicle speed and car navigation information. Since the necessary information is displayed in a limited space, it is believed to reduce driving fatigue by reducing the need to shift one’s viewpoint.

Although head-up displays are still in their infancy, they have been adopted in many cars in recent years. It is also a component that may be sold separately and can be retrofitted.

Uses of Head-Up Displays

Head-up displays are used to project information necessary for driving in the driver’s line of sight. The main information displayed in head-up displays includes speed, navigation information, and fuel level.

Usually, the navigation system can be placed between the driver’s seat and the passenger’s seat. However, when the information is projected on the head-up displays, there is no need to remove one’s eyes from the car. Therefore, it is expected to become more widely used from the standpoint of preventing people from looking away from the car.

Principle of Head-Up Displays

Head-up displays are transmissive displays. In order to project the image transparently, a device is used to project the image.

When a portion of the windshield is used for head-up displays, mirrors are used instead of projecting information directly onto the windshield. The display unit that shows the necessary information is located in the dashboard, and the image projected from the display unit is magnified by a diffuser or magnifying glass, and what is projected onto the windshield is the reflected image.

At this time, the light path through which the image is actually projected and the light path perceived by the driver overlap, making the image appear to be reflected on the windshield. Because of this principle, areas other than those shown on the head-up displays appear transparent, the use of head-up displays reduces eye movement while driving.

Types of Head-Up Displays

In projection-type head-up displays, a translucent screen appears on a special display and shows information.

There is also a smartphone display type that projects a smartphone screen onto the display. Thus, the navigation system can be used without shifting the eyes to the smartphone. The smartphone is placed on the head-up displays device and information is obtained by reflecting it back. In other cases, the head-up displays device and the smartphone are connected via Wi-Fi to project information.

The irradiation type can project information onto the windshield. Images can be projected from the head-up displays and displayed directly on the windshield.

How to Select Head-Up Displays

There are two types of head-up displays: those that are connected to the vehicle failure diagnosis system installed in the vehicle and those that are linked to a smartphone. When using a vehicle diagnostic system, a cord connects the connector to the head-up displays, and if equipped with GPS, the display can be powered by USB and can use some functions.

For head-up displays that are connected to a smartphone, the basic functionality depends on the application. For the type with a reflective smartphone screen, the projected screen is inverted, so the smartphone screen must be inverted to display. When connected via wired or Bluetooth, Android Auto and Apple CarPlay can be used.

Structure of Head-Up Displays

The head-up displays can be connected to the car using a cigarette lighter socket or an on-board diagnostic monitoring device, like a car charger with a USB terminal, which provides electricity when connected to the car’s on-board cigarette lighter socket and can be easily disconnected. Onboard diagnostic equipment provides a steady supply of power and uninterrupted meter functionality. However, in-vehicle diagnostic equipment is difficult to remove.

What Is a Brake Pad?

Brake pads are one of the components of brake calipers in disc brakes, and together with disc rotors, they are one of the most important components that directly affect the braking action of a car or motorcycle.

Brake pads are installed so that the disc rotor is sandwiched between the brake pads from the inside and outside. By sandwiching the disc rotor, which rotates together with the wheels of the car or motorcycle, the brake pads generate frictional heat to stop the rotation of the wheels.

Since these parts generate friction directly with the disc rotor, brake pads gradually wear out with use. As they wear out, braking power decreases, so they are also a component that needs to be replaced periodically.

Uses of Brake Pads

Brake pads are components directly related to the operation of disc brakes. Therefore, they are installed in automobiles and motorcycles equipped with disc brakes, or in railroads, aircraft, construction machinery, and agricultural machinery that uses disc brakes.

In recent years, along with the spread of EBS (electronically controlled brake systems), disc brakes are now being used in commercial vehicles, where drum brakes were the norm.

Principle of Brake Pads

Although the method of brake actuation differs from that of a car, in which the brake pedal is depressed, to that of a motorcycle, in which the brake lever is pulled, the method and principle of brake actuation are the same.

By depressing the brake pedal in the driver’s seat of a car or pulling the brake lever of a motorcycle, this force is amplified by a doubling device called a brake booster.

This force is then converted to hydraulic pressure at the master cylinder, which applies pressure to the pistons in the Brake Calipers. The pressure pushes the piston against the disc rotor, causing friction between the Brake Pads and the disc rotor.

The energy of the rotational motion is released outward as thermal energy generated by the friction, and this is how the wheel stops rotating. Therefore, a brake can be said to be a device that mechanically converts kinetic energy into heat and reduces the kinetic energy of the wheel.

Types of Brake Pads

Brake pads can be broadly classified into the following four categories according to the materials used.

• Non-asbestos materials
• Semi-metallic materials
• Carbon metallic material
• Metallic materials

“Non-asbestos materials” are widely used in general, and each type has its own merits and demerits.

1. Non-Asbestos Material

This material is most commonly used in brake pads for Japanese automobiles and motorcycles because it causes less brake noise (squeal), brake dust, and load on the disc rotors.

Although its heat resistance is not very high, it is said to be the most suitable material for driving in urban areas. If you are not particularly particular about driving performance, non-asbestos material Brake Pads are the best choice.

2. Semi-Metallic Material

Semi-metallic brake pads have excellent controllability and wear resistance, and provide stable braking performance even when driving on circuits or in other conditions where the brakes are subjected to heavy loads. On the other hand, it has disadvantages, such as a tendency to generate brake noise (squeal) and to stain wheel wheels.

Semi-metallic material is recommended if you want to use one brake not only for city driving but also for circuit driving.

3. Metallic Material

This material is mainly used as brake pads for vehicles that are driven on circuits, such as racing cars. It has excellent heat resistance performance, and it provides outstanding braking and control performance even at high speeds and under high brake loads such as in circuit driving.

However, it is also prone to brake noise (squeal) and wheel contamination, and is difficult to brake at low speeds, placing a high load on the disc wheel.

Another disadvantage is that they deteriorate more quickly than non-asbestos or semi-metallic materials and must be replaced more frequently. It is not suitable for city driving and is best suited only for circuit driving.

4. Carbon Metallic Material

This material has excellent heat resistance and braking performance, and like metallic materials, it is also used in racing cars that are driven on circuits. It is prone to brake noise (squeal) and wheel contamination, and places a heavy load on the disc rotor.

However, it can also be used for city driving, as braking does not deteriorate at low speeds, as with metallic materials. They are best suited for sports cars and other vehicles where you want to enjoy a stable driving feel.

Other Information on Brake Pads

Brake Pads Life Span and Replacement Timing

Brake pads are used as friction materials, so they will wear out and braking performance will deteriorate over a long period.

Therefore, it is necessary to periodically replace brake pads at one’s own discretion when the brake pads have decreased to 3 mm or less, or when the vehicle has traveled 30,000 to 50,000 km in terms of mileage.

In addition, regardless of the decrease in brake pads or the mileage, if the brakes become less effective or if abnormal noises are heard when braking, it is likely that there is something wrong with the operation of the brake pads. Since these parts are directly related to vehicle safety, it is important to inspect and replace them as soon as possible in case of an emergency.

What Is a Brake Caliper?

Brake calipers are one of the components of a disc brake, and their main function is to control the movement of the brake pads.

The brake caliper is an important component that holds the disc wheel, which rotates with the wheel, between the brake pads and generates frictional heat to stop the wheel from moving.

Uses of Brake Calipers

Disc brakes are used on the wheels of all kinds of vehicles, including automobiles, motorcycles, aircraft, agricultural machinery, construction equipment, and railroads, and all wheels that use disc brakes have brake calipers.

In recent years, disc brakes have also been used in commercial vehicles, where drum brakes are the norm.

Principle of Brake Calipers

By depressing the brake pedal in the driver’s seat of a car or pulling the brake lever of a motorcycle, hydraulic pressure is applied to oil called brake fluid.

The force of this hydraulic pressure is used to apply pressure to the pistons in the brake calipers, which in turn actuate the brake pads in the brake calipers. The brake pads press against the disc rotor, which rotates with the wheel, creating friction.

The heat generated by the friction causes the rotational energy (kinetic energy) of the wheel to be released in the form of heat energy, which reduces the rotational energy of the wheel and stops the wheel from moving.

Types of Brake Calipers

There are three types of brake calipers as follows:

• Floating type
• Opposed type
• Sliding caliper type

Each of these types has different features, advantages and disadvantages, and the brake caliper to be adopted depends on what is important to you.

Specifically, the floating type is installed on light cars and compact cars, the opposed type on sports cars, luxury cars, and commercial vehicles, and the sliding caliper type on passenger cars and trucks.

1. Floating Type

Also called the floating type or one-push type. The piston is pressed against the disc rotor from one side rather than both sides, making it the simplest structure among brake calipers. It has the advantage of being lightweight, inexpensive, and easy to install because it has only one piston and cylinder and few components.

On the other hand, the noise generated during braking (rattle sound) and low rigidity are disadvantages. Because of these characteristics, this type is mainly used in inexpensive vehicles, such as light cars and compact cars.

2. Opposed Type

Also called fixed-side or opposed-piston type.

It has a structure in which pistons are pressed against the disc rotor from both sides, and its merits are its high braking performance and rigidity. There are also types with two or more pistons.

On the other hand, the disadvantage of this type is that it is heavier and more expensive than other types because it has more pistons than other types. Because of their ability to provide stable control and braking performance, they are used in commercial vehicles, luxury cars, and sports cars that require greater braking force.

3. Sliding Caliper Type

Based on the floating type, the number of pistons is increased to two.

The two pistons are back-to-back, and when one piston is pushed out, the other piston is pulled in. This type of brake caliper has two pistons and one cylinder. It can be said that this type of brake caliper compensates for the weak point of low rigidity while retaining the advantages of the floating type, such as low cost and lightweight.

The greatest advantage of this type is that it has fewer disadvantages than the floating and opposed types.

Other Information on Brake Calipers

1. Life Expectancy and Replacement Period of Brake Calipers

Brake calipers are expected to last approximately 100,000 km. Brake pads, one of the components of brake calipers, have a shorter life than brake calipers because they are in direct contact with the disc rotor. Therefore, it is important to have brake pads inspected.

Therefore, it is recommended that brake calipers be inspected at the same time as brake pads. Also, if you notice any brake problems, such as poor braking performance or unusual noises, it is necessary to inspect and replace the brake calipers as soon as possible.

2. Sticking Brake Calipers

One of the most common problems with brake calipers is sticking. Sticking refers to a malfunction in which rust or dirt adheres to the pistons inside the Brake Calipers, causing the pistons to move sluggishly or become stuck, and the brake pads are unable to return from the position where they are pressed against the disc rotors.

This means that the brakes remain active while driving, leading to brake damage, which is dangerous. In particular, if sticking occurs on only one wheel, the brakes will be applied on only one side of the car, making it impossible to control the car and leading to a major accident.

Since brake calipers can be replaced relatively inexpensively, it is important to inspect and replace them regularly before they become sticking or otherwise malfunctioning.

3. How to Inspect and Maintain Brake Calipers

Brake calipers can be inspected and maintained by yourself, but the cost of having a mechanic perform the maintenance is approximately 150 USD. The following points should be checked during maintenance:

• Presence of rust
• Deterioration of piston seals and oil seals
• Filling of brake fluid