Noise-Reducing THK BL Link Ball with High Load Capacity
Experience the most precious quality, THK BL Link Ball, accurately designed and manufactured for the high load capacity and noiseless performance. It always provides the top durability.
Product Introduction
The THK BL Link Ball is a combination ball stud and spherical sliding bearing that connects moving parts with little play. A precision-machined steel ball bearing is inside the die-cast holder and sealed boot. This lets the holder move smoothly even when it is under a lot of weight. A high-strength zinc alloy holder or an A-1 aluminum alloy for lighter versions connected perpendicularly to the carbon steel ball shank ensures that the BL series is tough and lasts a long time. The grease pockets on the top and bottom of the spherical area keep the assembly well-lubricated all the time. This cuts down on noise and friction a lot. The BL Link Ball is great for rod ends on vehicle height sensors and other precise machines that need to run quietly because it is sealed and always lubricated.
Recommended Products & Advantages
THK BL 16BD Link Ball
This THK BL Link Ball model is heavy-duty and has an M16×2 thread, which gives it the most strength and stability. The chromate-treated steel ball shank and strong zinc alloy holder make it very hard to wear down. Lithium grease pockets and a sealed NBR boot make it easy to move, even when it’s full. Because it is small and has a holder that is perpendicular to the axis, the BL 16BD can easily resist axial and radial forces.
- Material: The parts are an NBR rubber boot for sealing, a zinc alloy holder, and a steel ball shank with a chromate finish and an HV of at least 650.
- High Load: The static capacity is 36,400 N for big loads, and the yield strength is 26,900 N.
- Precision: To reduce play, the spherical clearance is 0.02–0.06 mm radially and ≤0.3 mm axially.
- Lubrication: The top and bottom both have grease chambers that are already filled with lithium-soap grease to help reduce friction.
- Applications: Helpful when you need to be quiet, like when you’re working with heavy link movements in robotics and automation.
THK BL 16D Link Ball
This version uses the M16×1.5 thread, which is similar to the 16BD model. The holder, which is made of a strong zinc-alloy, the ball shank, which is made of carburized steel, and the sealed NBR boot are all part of the same strong structure. This little male thread is perfect for setups that need a regular right-hand screw.
- Compact Holder: This small holder has grease channels and is very slippery.
- Load Specs: It can handle a static load of 36,400 N and a radial load of 26,900 N.
- The small ball clearance guarantees a secure, tight fit.
- Precision Fit: The boot and grease pockets inside the machine help keep noise down when it is moving.
- Quiet Operation: This technology is often used in machine linkages and mechanical levers for tasks that need reliable, quiet movement.
THK BL 14BD Link Ball
The M14×2 thread type is a medium-sized thread that is still strong. The holder is made of a strong zinc alloy, and the steel ball shank has been hardened to make it stronger. The NBR boot and the oil inside make it easy to move.
- Durable Design: A holder made of zinc alloy and a chromium-treated steel ball shank.
- The tight clearance should be between 0.02 and 0.06 mm radially and less than 0.3 mm axially for precise motion control.
- Load Capacity: Even though it is small, it can hold up to 36,400 N of static stress and 19,800 N of yield strength.
- Self-Lubricating: Grease pockets automatically keep the joint lubricated, which means less maintenance is needed.
- Versatile: Useful in many situations, like industrial machines, assembly lines, and anything else that needs a strong connection.
THK BL 14D Link Ball
The materials used in this standard model (BL14BD) are the same as those used in the M14×1.5 thread. It can still handle loads of 36,400 N static and 19,800 N yield, even though it has a simpler right-hand thread design.
- High-Strength Materials: The zinc-alloy housing and the hardened steel ball are both very strong.
- Compact Precision: Get a sealed boot that works quietly and fits tightly around the sphere with high accuracy.
- Load Ratings: The BL14BD has a static load capacity of 36,400 N.
- Easy Installation: M14 thread, standard, right-hand; caps with an “L” on them show left-hand versions.
- Applications: These joints and link mechanisms are great for equipment because they are strong and work smoothly.
Essential Advantages
Low-Noise Operation
The BL Link Balls have a boot that is already filled with grease and bearing surfaces that have been polished to make them less slippery and quieter. The action stays quiet and smooth even when it's loaded because the grease pockets are sealed and the tolerances are very good.
High Load Capacity
Static loads of up to 36,400 N and high yield strengths, like 26,900 N for BL16BD, can be handled by THK BL joints. Because of their heat-treated steel balls and strong alloy holders, they don't get tired or bend.
Compact Precision
There is almost no play because the design makes very little radial spherical clearance (0.02–0.06 mm). Its tight fit helps with damping and accuracy, which are important for precise automation and sensing.
Excellent Durability
Steel and zinc/aluminum alloys that have been treated with chromate are the most resistant to wear. When boots are sealed to keep dirt and oil out, the life of the parts in extreme conditions is greatly extended.
Easy Maintenance
The BL series is easy to take care of because it comes pre-lubricated and sealed. This "lifetime lubrication" design does away with the need for outside grease fittings and regular relubrication. This lowers maintenance costs and downtime.
More Products
BL 12BD Link Ball
A mid-size double-threaded model (M12×1.75) that offers robust load capacity (static 26,700 N). Ideal for moderate-duty linkages with limited space.
BL 4DA Link Ball
Ultra-compact design with M4×0.7 thread, for tiny actuators or sensors. Its aluminum alloy holder (BL-A series) keeps it lightweight yet strong.
BL 12D Link Ball
Standard male-threaded (M12×1.25) joint for medium loads. Combines precision (0.02–0.06 mm clearance) with sealed grease for smooth operation.
BL 10BD Link Ball
Double-threaded (M10×1.5) version of BL10. Balances strength with compact size. Useful for tight assemblies needing high lubricity in oscillating motion.
BL 10D Link Ball
Single-threaded (M10×1.25) model. Known for reliable performance in machinery and valves, with corrosion protection from chromate plating.
BL 8D Link Ball
Small (M8×1.25 thread) joint. Dimensions are just 45.5×19 mm, making it suitable for lightweight linkages. Its compact size and tight tolerances ensure precise control in small mechanisms.
BL 6D Link Ball
Very compact (M6×1) joint for minor loads. An affordable, lightweight option that still features THK’s high-precision steel ball and pre-filled grease for quiet operation.
BL 5DA Link Ball
M5×0.8 double-thread variant in the most petite sizes. Its precision-fit housing and boot sealing make it great for tiny robots or precision instruments.
RBI 5D Link Ball
A female-threaded (“rod end”) version of BL5. The high-strength zinc alloy holder and sealed design enable it to withstand loads in line with the holder.
RBI 16BD Link Ball
Heavy-duty rod end with M16×2 internal thread. It can handle both compressive and tensile loads along the shaft axis, thanks to its dual threaded design and strong materials.
RBI 16D Link Ball
Similar to RBI 16BD but with a standard right-hand M16×1.5 thread. Suitable for industrial applications that require a female mounting end.
RBI 14BD Link Ball
Robust female thread (M14×2) variant with 36,400 N capacity. Provides a direct, threaded connection in automated link mechanisms.
RBI 14D Link Ball
M14×1.5 female thread joint for medium loads. Its sealed construction and high endurance make it a durable choice for assembly and transport equipment.
RBI 12BD Link Ball
M12×1.75 female-threaded link ball, high-strength zinc alloy housing. Offers stable performance in conveyor or guide link supports.
RBI 12D Link Ball
M12×1.25 female thread, standard design. Excellent for robotic arms and fixtures where space is limited.
RBI 10BD Link Ball
Female M10×1.5 thread. Compact yet robust, often used in pneumatic actuators and control linkages.
RBI 10D Link Ball
Female M10×1.25 thread. Lightweight design suits delicate applications while maintaining the same sealed lubrication feature.
RBI 8D Link Ball
Female M8×1.25, small size for precision instrumentation. Boots protect internal grease, ensuring smooth action in small pivots.
RBI 6D Link Ball
Smallest female link ball (M6×1). Ideal for hobbyists or prototyping applications that require low noise and easy assembly.
Suggested Product Types
Both types give a smooth, strong, and long‑lasting surface for seals. Regardless of the size of your shaft, SKF has a sleeve that suits your needs.
THK BL / BL-BD Series
The THK BL / BL-BD series includes regular ball joints with either a male threaded holder (BL) or a double-thread holder (BL-BD). They are THK’s main series and use a holder made of a strong zinc alloy and a steel ball. Choose BL-BD (with “L” for left-hand) if you want a joint with both a male and female thread.
THK BL-A Aluminum Link Ball
This version is lighter because it has an A-1 aluminum alloy holder. It is a great choice for robotics and car parts because it is light and strong at the same time. The only sizes that come in BL-A are BL4DA and BL5DA.
THK RBI Series (Female Holder)
Integrated rod-end bearings with a female-threaded holder that lines up with the ball shank axis. The design can handle both lateral and axial stresses (tension and compression). The application needs the threads of the bolts to line up. It is very resistant to wear thanks to its grease seal, which is the same as the BL series.
THK BJ Series (Ball Joint)
You could also check out THK’s BJ series of ball joints, like the BJ12H. Instead of the usual round rod ends, these have ball studs. The BL series is smaller overall because it was made to work with link mechanisms. BJ joints also make the steering and suspension system more flexible.
Custom-Engineered Solutions
THK and NOKS may be able to make custom link ball solutions for you based on your needs. You can change the thread size, shank length, and ball diameter through dimensional ordering to fit certain link lengths. You can choose between balls made of stainless steel or balls coated with a certain material. You can replace the NBR boots with rubber boots made from fluoro or silicone for use in places with high temperatures or chemicals. You can also change how often you lubricate. Our experts can change the ball’s hardness and plating to make it more resistant to corrosion. Nickel or trivalent chromate are two options. We can make a THK BL Link Ball just for you by changing these settings.
Interactive Size / Selector Tool
THK has an online tool that can help you pick the best link ball model. You can use the Optimal Product Selection Tool to find a THK Link Ball or rod end bearing model that fits your needs by entering the load, orientation, and environmental variables. The tool also gives you CAD drawings and estimates of how long things will last. We’ve added an interactive size selector to help you pick the best THK series for your design. Engineers can use this free tool on THK’s website to make it easier to choose products.
Industries and Applications
Industrial Automation & Robotics
The BL connect Ball is the best way to connect motion in machines and robots. It has sealed lubrication and is very accurate, so it’s perfect for assembly lines, packing, and pick-and-place systems.
Automobile (Height and Load Sensors)
THK BL Link Balls are used in the rod ends and linkage joints of automotive suspension height sensors. They are quiet and last a long time. These automobile height sensor rod ends are great for use in places where there is moisture and road debris because they have a chromate coating and a sealed boot.
Machine Tools & Precision Instruments
The BL joint has a spherical slide bearing ball stud interface with very little play, which makes it perfect for CNC machines and measuring tools. Their high wear resistance makes sure that the accuracy of the instruments lasts a long time.
Transport & Conveyors
The BL is a great part of material handling systems used in transportation and conveyors because it can handle misalignment without squeaking and can handle pulling and pushing loads (especially RBI female varieties).
Medical & Assistive Devices
The small THK BL-A aluminum link balls are used in medical robots and adjustable equipment because they are light and quiet, which are important for these devices.
Aerospace & Defense
Lightweight metals and the right high-temperature greases make it possible to make BL versions that work with aircraft link mechanisms. The precise fit of aircraft control systems helps them meet strict tolerances.