ハードロック工業 List of Products and Services

The "SLB Space Lock Bearing Nut" is a powerful return-stop lock nut with a hexagonal shape and pre-loading torque type. It is a groundbreaking product that does not damage the threads of the bolt during tightening and maintains its return-stop function even after reuse. Since it can maintain the appropriate initial preload for a long time, it prevents various damages to bearings caused by a decrease in rigidity. 【Features】 ■ Maintains strong return-stop effect even after reuse ■ Can be reused without damaging the threads, even on shafts with keyway machining ■ Hexagonal shape makes tightening easy and efficient ■ Thread strength is twice that of standard lock nuts ■ Good balance of the nut's center of gravity *For more details, please refer to the related links or feel free to contact us.

• nut

Content Overview 【Loosening of Screws】 Principles/Types/Evaluation/Testing/Countermeasures 【Design and Tightening of Screw Fasteners】 Mechanics/Design of Screw Fasteners/Screw Tightening Methods/Screw Tightening Tools 【About Screws】 Standards/Types and Usage/Materials/Surface Treatment/Strength of Screw Components 【Screw Troubles】 Troubles during Screw Tightening/Troubles after Screw Tightening/Others (Troubles) ↓↓For more details, click here↓↓

• bolt

Fatigue failure is a destructive phenomenon that occurs suddenly and without warning under conditions where a constant load is applied repeatedly, and it can also occur with variable loads. On our technical information site "Screw Fastening Technology Navigation," which contributes to solving issues related to screw fastening, we provide detailed information about metal damage known as "fatigue failure." Please take a look through the related links. [Contents] ■ What is fatigue failure? - Evaluation of fatigue characteristics - Factors that change fatigue characteristics - Fatigue mechanisms ■ Characteristic fracture surfaces of fatigue failure - Beach marks - Striation patterns ■ Considerations for fatigue strength safety design *For more details, please feel free to contact us.

• bolt

The main forms of corrosion include "uniform corrosion, pitting corrosion, and galvanic corrosion." Other types of corrosion include "crevice corrosion," which occurs due to the formation of an oxygen concentration cell in tiny gaps on the order of microns, "grain boundary corrosion," where the grain boundaries preferentially corrode, "erosion corrosion," which involves the action of wear by fluids, and "high-temperature oxidation," which occurs in high-temperature atmospheres or steam. Our technical information site "Screw Fastening Technology Navi," which contributes to solving issues related to screw fastening, features the three main forms of corrosion (uniform corrosion, pitting corrosion, and galvanic corrosion). Please take a look through the related links. [Contents] ■ Main forms of corrosion - Uniform corrosion - Pitting corrosion - Galvanic corrosion ■ Special types of corrosion cracking - Stress corrosion cracking - Hydrogen embrittlement cracking *For more details, please feel free to contact us.

• bolt

The technical information site "Screw Fastening Technology Navi," which contributes to solving issues related to screw fastening that our company operates, introduces steel materials. As the basics of steel materials, it covers topics such as "the difference between steel and non-ferrous metals," "what carbon steel is," and "manufacturing methods," using diagrams and tables. Please take a look through the related links. 【Content Included】 ■ Basics of Steel Materials - Difference between Steel and Non-Ferrous Metals - What is Carbon Steel - Manufacturing Methods ■ About Heat Treatment - Basic Heat Treatment - Structural Changes Due to Heat Treatment ■ Major Steel Materials *For more details, please feel free to contact us.

• bolt

"Mechanical properties" refer to the collective mechanical characteristics possessed by metallic materials, with tensile strength, elongation, reduction of area, hardness, and impact value being representative examples. Our technical information site, "Screw Fastening Technology Navi," which addresses challenges in screw fastening, provides detailed information on representative mechanical properties using diagrams and tables. Please take a look through the related links. [Contents] ■ What are mechanical properties - Tensile tests and stress-strain diagrams - Reduction of area, hardness, impact value - Relationship between tensile strength and hardness ■ Representative mechanical properties - Steel materials - Non-ferrous metals *For more details, please feel free to contact us.

• bolt

There are a variety of tools available for tightening or loosening screws. Generally, tightening tools such as "spanners" and "megawrenches," as well as "monkey wrenches" and "pipe wrenches," are used. On our technical information site "Screw Fastening Technology Navi," which contributes to solving screw fastening challenges, we introduce some slightly special tightening tools. For more details, please refer to the related links. [Contents] ■ Torque Wrench ■ Impact Wrench ■ Power Wrench ■ Hook Spanner *For more information, please feel free to contact us.

• bolt

When tightening bolts and nuts, the points to be aware of regarding the relationship between the tightening torque and axial force in the threaded joint can be broadly categorized into the following two points: (1) When the tightening torque is too high relative to the strength of the bolt and nut. (2) When the tightening torque is too low relative to the strength of the bolt and nut. Our technical information site "Screw Fastening Technology Navi," which contributes to solving issues related to screw fastening, confirms the stresses that occur inside the bolt during fastening and addresses the issue of screw failure when the tightening torque is too high, providing detailed information on this topic. Please take a look at the related links. *For more details, please feel free to contact us.

• bolt

In the tightening of screws, when torque is applied to the nut while the bolt is in a state of axial force, the relationship between the bolt axial force and the torque applied to the nut is derived as an application of the "principle of the inclined plane." On our technical information site "Screw Fastening Technology Navi," which contributes to solving issues related to screw fastening, we provide detailed explanations of the principle of the inclined plane in the case of square screws, using diagrams and other materials. Please take a look through the related links. *For more details, feel free to contact us.

• bolt

When fixing the joined components, the types of fastening screws include bolts and nuts. Axial force refers to the force that occurs when a bolt is tightened; the bolt tightening area is pulled in the axial direction and stretches very slightly. The reactive force that tries to return it to its original state is the axial force. If the axial force is not within the appropriate range, it can cause loosening or lead to the destruction of the joined components, making daily management of proper tightening torque and axial force important. Now, to determine the necessary tightening torque for managing the appropriate axial force, it can be calculated using a simple formula. We provide detailed information on this topic on our technical information site, "Screw Fastening Technology Navigation," which contributes to solving screw fastening challenges. Please check it out through the related link. *For more details, please feel free to contact us.

• bolt

In the fastening of mechanical structures (screw fasteners), screws are important components. They can be removed when necessary. The ability to repair mechanical structures and reuse them is a key feature. According to the screw fastening general rules (JIS B 1083:2008), screw fastening is defined as the method or state of joining two or more items by fitting the threaded part of a bolt with the nut or the internally threaded part formed in the item, and tightening the screw. A screw fastening assembly is defined as the entire structure with a screw fastening part or a part of the structure that includes the screw fastening part. Our technical information site "Screw Fastening Technology Navigation," which contributes to solving screw fastening challenges, provides detailed information about "the structure of screws." Please take a look through the related links. *For more details, please feel free to contact us.

• bolt

The technical information site "Screw Fastening Technology Navigation," which contributes to solving issues related to screw fastening that our company operates, introduces the "design of screw fastening bodies." We explain the design methods for a bolt fastening body that connects two hollow cylinders with a single bolt and nut. We provide detailed explanations with diagrams and formulas on how to design the bolt to meet specific conditions and the design policies for each condition. Please take a look through the related links. [Content Included] ■ How should bolts for screw fastening bodies be designed? ■ What is the internal force coefficient Φ? *For more details, please feel free to contact us.

• bolt

The Junker axial perpendicular vibration test is a test for the loosening of screws caused by repeated loads in the axial perpendicular direction. The principle of the Junker test is illustrated in the left diagram. By applying repeated forces in the perpendicular direction to the axis of the screw, a loosening torque is generated, and the changes in axial force are continuously measured. In actual usage scenarios of screws and bolts, vibrations occur regularly and are a primary cause of loosening. The Junker testing machine artificially generates vibrations in the axial perpendicular direction, which are prone to cause a decrease in axial force, allowing for observation and verification. *For more details, please refer to the PDF materials or feel free to contact us.*

• bolt

The NAS test refers to the accelerated vibration test described in the U.S. aerospace standards: NAS (NATIONAL AEROSPACE STANDARD) 3350/3354, which is commonly referred to as the NAS test. Since the test is based on the aviation industry, it emphasizes the effects of acceleration (deceleration) environments and high-temperature environments. At Hard Rock Industries, the "impact vibration test in accordance with NAS3350/3354" is referred to as the NAS test. Additionally, the U.S. aerospace standards primarily focus on heat-resistant alloys for the materials of applicable bolts and nuts, and specify the lubricants to be used, along with various other criteria. To properly conduct a NAS test, it is necessary to adhere to all these standards; however, for products intended for the Japanese market, tests that conform to the NAS test are generally conducted. *For more details, please refer to the PDF document or feel free to contact us.*

• bolt

When physically defining the loosening of bolts and nuts, it can be defined as "a decrease in clamping force (bolt axial force)." So, what factors contribute to this decrease in clamping force? They can be broadly divided into two categories: "loosening due to non-rotation of the threaded part" and "loosening due to rotation of the threaded part." When considering anti-loosening measures, it is necessary to examine these two factors. In the products of Hard Lock Industries, development focuses on how to prevent loosening caused by the rotation of the threads, and they possess overwhelmingly superior anti-loosening characteristics. [External force factors of loosening due to thread rotation] 1. Axial direction of the bolt 2. Direction perpendicular to the bolt axis 3. Direction around the bolt axis *For more details, please refer to the PDF materials or feel free to contact us.

• bolt

To perform safe screw fastening, sufficient initial tightening force F is required, and for that, it is necessary to tighten with an appropriate tightening torque T. The characteristics of the tightening methods for screw fasteners can be broadly divided into two categories: elastic region tightening and plastic region tightening. Therefore, when fastening bolts, it is important to select the appropriate strength classification (yield stress) and friction coefficient that correspond to the target bolt axial force. Thus, to perform proper screw tightening, it can be said that it is essential to have a good understanding of the friction coefficient, which greatly influences the tightening torque and initial tightening force. [Tightening Methods for Screw Fasteners] ■ Elastic Region Tightening: Tightening within the range where the bolt does not yield ■ Plastic Region Tightening: Tightening within the range where the bolt yields and reaches the limit tightening axial force *For more details, please refer to the PDF document or feel free to contact us.

• bolt

In addition to the direction perpendicular to the bolt axis, axial repeated loads can also cause loosening. In the case of axial repeated loads, if the bolt and nut are properly tightened and sufficient initial axial force is applied, even when subjected to a large repeated load of 80% of the bolt yield axial force Fy, it can be understood that even standard hex nuts are less likely to experience rotational loosening. On the other hand, if the initial axial force significantly decreases due to some factor, hex nuts and hex nuts with spring washers will completely experience rotational loosening at 50% of the bolt yield axial force Fy, and even double nuts will see the initial axial force drop to about half. From the above results, it can be understood that in the case of hard lock nuts, even when the initial axial force is low or decreases due to some factor, they are less likely to experience rotational loosening. *For more details, please refer to the PDF document or feel free to contact us.

• bolt

The loosening of screws can be broadly classified into two types. There is "rotational loosening," which occurs when the male and female threads rotate relative to each other in the direction of loosening, and "non-rotational loosening," which occurs even when they are not rotating relative to each other. Furthermore, screws are used extensively in our daily lives. However, when screws loosen when we do not want them to, it can not only disrupt our lives but also lead to major accidents. It is important that screws do not loosen when we do not want them to, and that they do loosen when we want them to. Research on screw loosening and prevention is considered urgent. 【Classification of Loosening】 ■ Rotational Loosening ■ Non-Rotational Loosening *For more details, please refer to the PDF document or feel free to contact us.

• bolt

The damage to screws and bolts can be broadly classified into three categories: "damage," "failure," and "fracture." Damage refers to the separation of a part of the material or the occurrence of permanent deformation, and it does not necessarily imply a hindrance to use. Failure refers to the separation of a part or the whole of the material or the occurrence of significantly large permanent deformation that renders it unusable, while fracture refers to the material breaking apart and separating. In other words, the damage/fracture of a bolt occurs on the surface of the bolt, particularly from the bottom of the thread valley where stress concentration is high. For a more detailed explanation, please refer to the related link page. 【Forms of Bolt Damage】 ■ Damage: Separation of a part of the material or occurrence of permanent deformation ■ Failure: Separation of a part or the whole of the material or occurrence of significantly large permanent deformation that renders it unusable ■ Fracture: Material breaks apart and separates *For more details, please refer to the PDF materials or feel free to contact us.

• bolt

The cause of loosening screws lies in the play (clearance) of the threads between the bolt and the nut, and if this can be completely eliminated, it would achieve the ideal anti-loosening effect. Our anti-loosening effect utilizes the "wedge," which has been used in wooden construction for a long time. We have conducted extensive research and developed a product that applies the principle of this "wedge" to nuts. That groundbreaking product is the 'HLN Hard Lock Nut.' 【Features of HLN Hard Lock Nut】 ■ Anti-loosening effect recognized worldwide ■ Torque and axial force management possible ■ Reusable ■ Easy and good workability ■ Contributes to significant cost reduction *For more details, please refer to the PDF document or feel free to contact us.

• nut

The loosening of screws is related to the decrease in fastening force (bolt axial force), and the causes can be broadly divided into two categories: "non-rotational loosening of screws" and "rotational loosening of screws." When the bolt axial force is low or decreases, the number of cycles until bolt failure decreases, leading to a very dangerous situation. In combination with measures against non-rotational loosening, our 'HLN Hard Lock Nut' exhibits a powerful anti-loosening effect based on the principle of wedging. Therefore, you can use it with confidence without worrying about a decrease in fastening force. [Causes of Screw Loosening] ■ Non-rotational loosening of screws - Initial settling - Indentation loosening - Loosening due to micro-motion wear, excessive tightening, and other external forces - Loosening due to thermal causes ■ Rotational loosening of screws *For more details, please refer to the PDF document or feel free to contact us.

• bolt

The "HLS [Hard Lock Set Screw] (R)" is a locking part developed from the application of the wedge principle, similar to HLN and HLB, which support safety in industrial society for mold fastening. Like the hard lock nut, it provides stable and lasting anti-loosening effects under all conditions, and being made entirely of metal, it has minimal wear and maintains a high anti-loosening effect. It meets the needs of various fields, from industrial machinery to mold fixation. 【Features】 ■ Extremely high anti-loosening effect and semi-permanent ■ Reusable ■ Easy and good workability ■ Provides economic benefits *For more details, please download the PDF or feel free to contact us.

• nut

It has a strong anti-loosening effect that is not found in other lock nuts, as well as excellent workability and ease of attachment and detachment.

• bolt

The Hard Lock® nut, born in Japan and growing globally, possesses a strong anti-loosening effect not found in other lock nuts, along with excellent workability and ease of attachment and detachment. Could the principle of a wedge be applied to prevent loosening? This theme was tackled, and after repeated trial and error, the Hard Lock nut was completed.

• Other safety equipment