月: 2022年12月

What Is a Rod End Bearing?

Rod end bearings, incorporating a spherical plain bearing within the housing, are also known as “rod ends” or “spherical plain bearing rod ends.” They are used in assemblies for connecting parts and facilitating relative motion.

Uses of Rod End Bearings

Figure 1. Example of Rod End Bearing Use

Rod end bearings are essential in various sectors, including construction, industrial machinery, automotive, and aviation. They are pivotal in connecting and transmitting motion in parts that undergo rotational or oscillating movements. For instance, as shown in Figure 1, they are utilized in production lines to control the movement of workpieces.

The rod-end housing ends, featuring either “male” or “female” threads, are designed for secure attachment, allowing for the relative displacement of connected parts through a spherical sliding structure.

Principle of Rod End Bearings

Rod end bearings facilitate smooth and flexible rotational motion, enabling connected parts to rotate and tilt freely, akin to human joints. They are capable of withstanding high loads, making them suitable for heavy-duty applications.

Structure of Rod End Bearings

Figure 2. Structure of Rod End Bearing

As depicted in Figure 2, a rod end bearing comprises a “bush” (inner ring) and a “rod end housing” (outer part with threads for connection). These components allow for adjustable connections by threading the male rod into the female-threaded rod end housing.

Types of Rod End Bearings

Figure 3. Types of Rod Ends

Rod end bearings vary by shape, lubrication, and material, each tailored for specific applications and requirements.

• Shape: Choose between male and female threaded housings to match the connecting rods.
• Lubrication: Options include lubricated (greased) or unlubricated types, with the latter incorporating a lubricating synthetic resin for maintenance-free applications.
• Material: Materials range from carbon steel to high-carbon chromium-bearing steel and self-lubricating synthetic resins, selected based on environmental conditions and load requirements.

Additionally, resin-made rod ends offer lightweight, maintenance-free options suitable for environments with contaminants.

Others

Figure 4. Link Ball

Link balls, another variant, combine a threaded shaft with a bushing, often covered with a rubber boot to prevent ingress of water and dust, with lubricant sealed within for smooth operation.

What Is a Coil Spring?

A coil spring, primarily made of metal wire, stores energy when compressed, pulled, or twisted. This energy then acts as a restoring force. There are three types of coil springs based on their function: compression springs for compression, tension springs for pulling, and torsion springs for twisting.

Coil springs are widely used in automobiles and machine tools to absorb shock and vibration, and in various machines and everyday items that require a return action, such as push buttons.

Uses of Coil Springs

Coil springs serve two primary functions: returning to their original length by repulsive force, and absorbing shock and vibration. Repulsive force applications include ballpoint pens, bicycle locks, and automatic tape measures. Shock-absorbing applications feature automobile suspensions and shock absorbers on Tarzan ropes.

Principle of Coil Springs

Coil springs operate on elastic energy from the wire’s plastic deformation. The restoring force is proportional to compressive displacement. The spring constant, determined by dividing the restoring force by displacement, varies with wire diameter. When selecting coil springs, both the spring constant and the spring length are important considerations.

For repulsive force applications, the spring constant is estimated based on the intended displacement and required force. In shock absorption, the spring constant is chosen based on displacement length and expected load. To avoid resonance, the system’s natural frequency should not match external periodic forces. Often, dampers are used alongside coil springs to provide resistance and control displacement rate.

Coil Springs in Dental Applications

In orthodontics, coil springs apply force to teeth for corrective treatment. They are often made from cobalt-chrome alloy and chosen based on the direction of tooth movement. Open coil springs widen the gap between teeth, while closed springs are used to close gaps. It’s crucial to ensure compatibility with the patient’s body to avoid allergic reactions.

Coil Springs for Automotive Applications

Automotive coil springs are integral to vehicle suspensions, often combined with shock absorbers. The spring’s characteristics, like wire diameter, length, and number of turns, influence the suspension’s performance. Various types of coil springs, such as equal pitch, unequal pitch, and nonlinear pitch, respond differently to shocks. While coil springs absorb shocks, shock absorbers paired with them help control vibrations more quickly.

What Is a Measuring Gauge?

Measuring gauge is a general term for measuring instruments with reference dimensions, angles, shapes, etc.

It is mainly used in the manufacturing process to determine if the machined dimensions, etc., are acceptable or not. Measuring gauges are not calipers or micrometers that measure dimensions. It is a tool to determine whether the dimensions of an object to be inspected are within the standard range.

When measuring dimensions with a measuring instrument, the speed and quality of the inspection process can vary depending on the skill level of the inspector. However, using a Measuring Guage, it is easy to determine whether a product is acceptable or not. Differences in operator skill are less likely to appear, and the gauges are easy to handle.

In addition, measuring gauges can be used not only for on-site inspections but also for quality control between different companies. The same gauges as those used in the company can be handed over to sub-contractors, and the same dimensional control can be performed between the two companies by simply telling them to use the gauges for control.

Uses of Measuring Gauges

Measuring gauges are used in industrial product manufacturing lines. They are used during the manufacturing process and in final inspections to check whether the machined parts and dimensions quickly that are important to the function of the product are within specifications.

In addition, measuring gauges with a set of multiple sizes, such as pin gauges and crevice gauges described below, can be used to check the approximate size of the inside diameter of a very narrow gap or a relatively small hole.

Principle of Measuring Gauges

A measuring gauge is finished to a standard dimension. By placing a measuring gauge finished to the standard dimension over or through the part to be inspected, it is possible to determine whether the size of the part to be inspected is larger or smaller than the measuring gauge.

For example, if a 5 mm diameter finished Measuring Guage can pass through a machined hole that requires a 5 mm diameter, the diameter of the machined hole can be judged to be larger than 5 mm diameter. Furthermore, if a measuring gauge finished to 5.1 mm in diameter cannot pass through the hole, the inside diameter of the machined hole can be judged to be smaller than 5.1 mm in diameter.

By comparing the machined part at the manufacturing site with a measuring gauge whose dimensions are known, it is possible to determine quickly whether the finished dimensions are within the standard range without using a measuring instrument, such as a caliper.

Types of Measuring Gauges

There are various types of measuring gauges. The main types of measuring gauges are as follows:

• Block Gage: A “length” standard used to check the accuracy of measuring instruments.
• Skimmer Gauge: Gauges used to measure the dimensions of the gap between two surfaces.
• Welding Gauges: Gauges capable of making a wide variety of welding-related measurements.
• Angle Gauges: Gauges used for angle inspection.
• Pitch Gauges: Gauges used to check the pitch of screws.
• Filler Gauges: Gauges used to measure the dimensions of narrow gaps.
• Taper Gauges: Gauges used to measure gaps and hole diameters.
• Center Gauges: Gauges used to check the angles of turning tool cutting edges when threading on a lathe.
• Radius Gauges: Gauges used to inspect the radius (curved part) of a product.
• C-Face Measuring Gauge: Gauge used to measure the size of the C-face after C-chamfering.
• Pin Gauges: Gauges used to measure the diameter of holes.

Other Information on Measuring Gauges

Precautions for Handling Measuring Gauges

Materials, not just measuring gauges, will change dimensions depending on temperature. When handling measuring gauges, make sure they are not extremely heated or cooled. The same applies not only to measuring gauges but also to inspection objects.

In addition, in inspections that are used repeatedly, there is a possibility that wear may occur on the parts that rub against each other over a long period. Measurement gauges, like measuring instruments, should be calibrated periodically to check for dimensional accuracy.

What Is a Flat Spring?

A flat spring is crafted from a thin metal plate, typically fabricated through press working. With a thickness usually less than 1 mm, they are a staple in household products due to their cost-efficiency and suitability for mass production.

Although their thin form factors contribute to lightweight and simple design advantages, this also limits their strength. As such, careful selection of materials and design is crucial to prevent deformation or damage under excessive loads or varying operational conditions.

Uses of Flat Springs

Flat springs are integral to diverse applications across different industries:

1. Daily Necessities and Stationery

Utilized in items like tweezers and ballpoint pen clips, flat springs leverage their restorative force to clamp objects, enhancing operability and functionality in precision tools.

2. Sports-Related

Employed in equipment such as diving boards and snowboards, flat springs adjust flexibility and stiffness, absorbing impacts to improve the athlete’s experience.

3. Electronic Equipment

In electronic devices, they actuate button switches and establish reliable electrical connections in circuit contacts, crucial for user feedback and signal control.

Principle of Flat Springs

Designed primarily in flat, wavy, or curved shapes to facilitate easy deformation, flat springs are made from high-strength metals like stainless steel or aluminum, tailored to their specific applications. The principle of operation aligns with beam calculation models, where stress and deflection are key considerations.

How to Select a Flat Spring

Selecting the right flat spring involves considering load capacity, deformation, material, size, and mounting method to ensure compatibility with application requirements and operational environments.

1. Load Capacity and Deformation

Assess the spring’s ability to absorb the intended load and achieve the required deformation, selecting a thickness that meets these design specifications.

2. Material

Choose a material based on the need for corrosion resistance or strength, with options like stainless steel or alloy steel. Protective coatings may also be applied to enhance durability.

3. Size

The spring’s dimensions should accommodate the load, deformation, and available mounting space, ensuring a proper fit and function.

4. Mounting Method

Stable securing of the spring through methods like welding or clamping is essential for optimal performance, taking into account the spring’s integration within the device or structure.

What Is a Plastic Nut?

A plastic nut is molded from resin, distinguishing it from traditional metal nuts.

Nuts are components that, used alongside bolts and screws, fasten or assemble machinery. They have a threaded center hole; bolts have male threads, whereas nuts have female threads.

Being lightweight, plastic nuts are favored in applications where reducing weight or mitigating vibration is crucial. They also serve as excellent electrical insulators, making them ideal for electrical insulation needs.

However, resin tends to be more brittle and less durable than metal, necessitating caution when using plastic nuts in high forces applications.

Uses of Plastic Nuts

Plastic nuts find use in various applications, leveraging their unique properties. Below are some examples:

1. Electronic Equipment

In electronic equipment and electrical wiring systems, plastic nuts provide superior insulation compared to metal nuts, securing electronic components and wiring effectively. Their application is crucial in preventing short-circuit failures in computers and household appliances, where electrical insulation is paramount.

2. Furniture

They are employed in assembling household utensils and furniture, favored for their lightweight yet sufficient strength for fixing. Applications include furniture legs, handles, and small assembly parts.

3. Outdoor Lighting

The corrosion resistance of plastic nuts benefits the assembly of outdoor lighting and components, offering a viable alternative to metal nuts prone to corrosion.

4. Plastic Products

When assembling plastic parts, using metal nuts may cause damage. Plastic nuts, less likely to harm plastic components, are preferred for assembling plastic enclosures and covers.

Characteristics of Plastic Nuts

Plastic nuts, made from plastic materials, are utilized for fastening along with bolts and screws. Key characteristics include electrical insulation and lightweight. Their insulation property is particularly valued in electronic device assembly. Additionally, their flexibility and vibration absorption capacity surpasses that of metal nuts.

Types of Plastic Nuts

Various plastic materials are used to manufacture plastic nuts, each with distinct advantages:

1. Polypropylene Nut

Polypropylene, known for its lightweight, chemical resistance, and low density, is suited for lightweight constructions and withstands outdoor and humid environments.

2. Nylon Nut

Nylon nuts, celebrated for their durability and chemical and vibration resistance, are versatile, fitting for insulation-required and lightweight assemblies.

3. Polycarbonate Nut

Polycarbonate, a resin known for its high transparency, impact, and heat resistance, is often chosen for transparent parts and lighting applications.

4. Polyethylene Nut

Polyethylene nuts are recognized for their durability, chemical resistance, and resilience against chemical corrosion and decay, making them suitable for outdoor use or environments with chemical exposure.

5. Polyvinyl Chloride Nut

These nuts offer excellent insulation and chemical resistance, are easy to process, and are cost-effective. However, their strength may be compromised in high-temperature and high-load conditions.

What Is a Hand Saw?

A hand saw is a manual saw capable of cutting various materials including metal, plastic, wood, and polyvinyl chloride. Its versatility and independence from a power source make it an ideal tool for home use.

There are two main types of hand saws: those with replaceable blades and those with fixed blades. The replaceable blade type offers more flexibility for different applications and longevity, as the blade can be switched out as needed.

Uses of Hand Saws

Hand saws are commonly used for cutting metal, plastic, wood, and other materials, especially in DIY carpentry, and for breaking down bulky waste at home. They are particularly effective for cutting materials with smaller cutting areas, such as pipes and bars. For cutting aluminum, stainless steel, plastic panels, and pipes, a hand saw is often preferred over a wood saw.

They are handy tools to keep at home for various cutting needs.

Principle of Hand Saws

Hand saws typically feature a bow-like body with a thin, narrow blade. The blade is tensioned using a screw at the tip, preventing bending during use and facilitating the cutting of hard materials. Handles are often an extension of the blade, designed for comfortable grip and efficient force application. They may be rubber-coated or wooden, and some models feature a vertical grip, like Western saws, for enhanced force application, especially for cutting harder materials.

The blades are usually made of durable materials like bimetal or cobalt, ensuring longevity and safety, as they are less likely to shatter if broken. Some hand saws are stringless and more suited for cutting smaller parts due to lower blade tension.

What Is Vacuum Hose?

Vacuum hoses are specialized hoses designed for transporting liquids and gases under conditions of high vacuum, where the pressure is significantly lower than the atmospheric pressure. These hoses are critical in various industries and research fields due to their ability to maintain a clean and controlled environment by preventing the entry of foreign particles and impurities.

Applications of Vacuum Hose

Vacuum hoses are pivotal in numerous sectors:

1. Semiconductor Manufacturing Industry

In semiconductor production, maintaining cleanliness is crucial due to the fine structures of semiconductors. Vacuum hoses facilitate the supply and discharge of materials and gases, preserving the necessary clean conditions.

2. Space Industry

They are integral to spacecraft manufacturing and testing, handling the vacuum conditions of outer space and ensuring the reliability of space probes and equipment.

3. Pharmaceutical Manufacturing Industry

Vacuum hoses contribute to the sterile environment required in pharmaceutical and biological product manufacturing, preventing contamination and ensuring product safety and quality.

4. Research Field

In research fields like physics and chemistry, vacuum hoses are essential for creating specific experimental conditions under vacuum, facilitating the study of gas and heat conduction and elementary particle behavior.

5. Industrial Applications

These hoses support various industrial processes needing vacuum conditions, such as heat treatment, degassing, and coating, by providing precise control over vacuum levels.

Principles of Vacuum Hose

Vacuum hoses operate on fundamental principles to control gas movement:

1. Molecular Movement and Diffusion

Under low pressure, gas molecules inside the hose move from areas of high pressure to low pressure, facilitated by the hose’s connection to vacuum chambers or pumps, guiding the molecules in the desired direction.

2. Effect of Pressure Difference

By connecting areas of different pressures, vacuum hoses enable gas molecules to move towards lower pressure areas, balancing the pressure distribution within the hose.

3. Relationship between Flow Velocity and Pressure

The flow rate of gas inside a vacuum hose increases with the pressure difference, allowing efficient movement and exhaust of gases.

Structure of Vacuum Hose

Vacuum hoses are constructed with smooth internal surfaces and materials that minimize gas molecule collisions. They are durable and resistant to chemicals, maintaining high vacuum conditions over time.

Types of Vacuum Hose

Various types exist catering to specific applications:

1. Rubber Vacuum Hose

Flexible and economical, suitable for general vacuum applications across a wide temperature range.

2. Plastic Vacuum Hose

Lightweight and chemically resistant, ideal for medical and analytical equipment.

3. Metal Vacuum Hose

Highly durable and resistant to pressure, perfect for advanced vacuum experiments and industrial use.

4. Silicone Vacuum Hose

High-temperature resistance, stable in various conditions, and find applications in the medical and food industries.

5. Composite Material Vacuum Hose

Combines properties of different materials to meet diverse requirements, offering customized performance advantages for specific needs.

What Is a Flat Belt?

A flat belt is characterized by its flat, rectangular cross-section, distinguishing it from V-shaped belts. It is a flexible, stretchable belt used for connecting multiple shafts, offering the advantage of shock absorption during power transmission. This capability allows it to dampen sudden load changes and vibrations between machine components, while its ability to slip intentionally reduces damage during overloads. However, flat belts generally have lower force transmission capabilities compared to V-belts and require careful design for handling high torques and loads, especially at high rotational speeds.

Applications of Flat Belts

Flat belts serve various purposes across multiple industries:

1. Industrial Machinery

In factories, flat belts are crucial for transmitting power from motors to pumps, fans, compressors, and more, prized for their overload protection and shock absorption qualities.

2. Automotive

These belts facilitate power transmission from car engines to generators and cooling fans, and are sometimes used in power steering and submersible pumps.

3. Agricultural Machinery

Flat belts are integral to agricultural machinery, such as mowers, enhancing the efficiency of power transmission from engines to various equipment for more effective farming operations.

4. Transportation Industry

They secure cargo to prevent movement during transit, safeguarding against damage or tipping over within vehicles.

Principles of Flat Belts

Comprising multiple layers, flat belts often feature a surface layer for wear resistance and durability, made from rubber or synthetic materials, and a reinforcing layer underneath, typically crafted from synthetic fibers like polyester, to bolster strength and load-bearing capabilities.

1. Surface Layer

This outer layer ensures wear resistance and protection from external elements, with its grip critical for effective power transmission.

2. Reinforcement Layer

Located beneath the surface, this layer enhances the belt’s strength and durability, distributing even force across the belt. It often consists of multiple layers oriented at various angles to balance strength and flexibility.

How to Choose a Flat Belt

Selecting the right flat belt involves considering:

1. Material

Choose based on the application and environment, with options ranging from rubber to synthetic materials, each offering different properties like wear and oil resistance.

2. Tensile Strength

Important for determining the belt’s load-bearing capacity, ensuring it matches the weight of the cargo to avoid damage.

3. Width

A wider belt distributes load more effectively, essential for securing large or heavy items.

4. Thickness

Affects strength and durability; thicker belts are stronger but may offer less flexibility, requiring a balance based on the nature of the load.

What Is a Crank Handle?

A crank handle is a mechanical input device that generates rotational output by manually rotating a handle. It typically consists of a lever (rod-shaped part) with a hole or shaft at one end, serving as the rotary output side, and a handle mounted in an L-shape for input.

A crank is a part of an axle or curved shaft, or an arm, keyed at right angles to the end of a shaft, converting reciprocating motion to circular motion or vice versa.

Uses of Crank Handles

Figure 1. Example of crank handle use

Crank handles are used in various applications requiring rotary motion. Common examples include handles for car jacks, window and louver openers, and fishing rod reels. In industrial settings, they are used for manual operations of valves, electric motors, gears, and machine tool positioning like lathes.

Figure 1 illustrates crank handles used for the manual operation of lifting devices and worm reduction gears.

Principle of Crank Handles

Crank handles function as mechanical input devices for manual rotary movements, consisting of a lever connecting a rotating shaft to an off-center shaft. They generate rotational output through manual rotation, offering leverage to reduce the required force.

The force needed to rotate a shaft, or torque, is calculated as follows:

Torque T(N-m) = Tangential force F(N) × Turning radius R(m)

The longer the lever, the more rotational force can be generated with less effort. However, longer levers make increasing rotational speed more difficult. Thus, lever length should be selected based on the required torque and rotational speed.

Types of Crank Handles

Figure 2. Types of crank handles (1)

Figure 3. Types of crank handles (2)

• Lever/Handle Material: Cast iron, carbon steel, stainless steel, aluminum alloy, resin
• Lever shape: Straight, offset
• Handle mounting: Fixed, rotating, rotating retractable
• Lever hole shape: Round hole, square hole
• Others: Ratchet shaft attachments, balance weight on opposite sides of the handle

Figure 4. Types of crank handles (3)

Crank Handles Selection

When selecting crank handles, consider the operating environment and workspace. Factors include the shaft shape, required operation force, material strength, handle accessibility, environmental conditions, and workspace limitations.

• Select a round or square hole according to the shaft shape.
• Choose the appropriate shaft and lever hole dimensions for the equipment.
• For operations requiring more force, opt for a longer lever.
• If high strength is needed, consider materials like carbon steel or stainless steel.
• Choose an offset handle to avoid interference with nearby equipment.
• Select a rotary or retractable handle if space is limited.
• For harsh environments, choose durable, weather-resistant materials.
• Consider a ratchet-type handle for a limited workspace.
• For tasks requiring many rotations, like lathe positioning, select a balanced handle.

What Is a Compression Spring?

A compression spring, also known as a compression coil spring, is used to absorb shock or support weight by utilizing the reaction force of a compressed spring. It’s the most common type of spring, typically cylindrical, but comes in various forms depending on its application and location. For instance, the spring inside a ballpoint pen, which helps return the pen tip, is a type of compression spring.

Characteristics of Compression Springs

Compression springs are primarily divided into “equal pitch coil springs” and “unequal pitch coil springs,” chosen based on load requirements and function.

1. Equal Pitch Coil Spring

Equal-pitch coil springs are perfectly cylindrical and exhibit a linear relationship between load and deflection. This linearity simplifies design and mathematical modeling. However, actual springs may differ from calculated values, particularly below 30% and above 70% of total deflection. This variance is due to end adhesion during compression, which slightly alters the effective number of coils.

Uses of Equal Pitch Coil Springs

These springs are used in applications such as gas-regulating valves, automobile suspensions, motorcycle clutches, retractable pens, spring beds, suitcase locks, and computer keyboards.

2. Unequal Pitch Coil Spring

Unequal pitch coil springs, varying in shape, exhibit a non-linear load-deflection relationship.

Types of Unequal Pitch Coil Springs

• Conical Coil Spring: This spring type, entirely conical, avoids coil interference during compression.
• Slack Coil Spring: Shaped like a large “slack,” used for space reduction at the ends.
• Tapered Coil Spring: A “pinched” shape that helps avoid central interference when compressed.

Uses of Unequal Pitch Coil Springs

Used in various applications, these springs are typically conical or barrel-shaped and found in battery case contact springs, foot switches, cock valves, space-saving springs, coffee filter handles, and in dampers for car suspensions and bridges.

Other Compression Springs

Beyond “equal pitch coil springs” and “unequal pitch coil springs,” there are numerous custom compression coil spring designs, each tailored for specific applications. The default winding direction is right-hand unless otherwise specified.

Other Information on Compression Springs

1. Selection of Compression Springs

When selecting a compression coil spring, factors such as spring constant, free length, and outside diameter are critical. The operational range is from the free length (no load) to the maximum allowable compression length. Proper installation often involves securing the springs at both ends with specific components, like spring washers.

2. Stress Design of Compression Coil Springs

Typically used under static load conditions, these springs should be selected so that their stress remains within the elastic limit of the material. It’s recommended to use springs where the maximum stress is below 80% of the material’s specified allowable torsional stress.