German BILZ coupling BILZ model BILZ price

BILZ couplings transmit motion by directly welding or bonding a thin-walled corrugated tube (bellows) to the two halves of the coupling. This type of coupling features a simple structure, compact dimensions, ease of machining and installation, and high transmission accuracy. It is primarily used in low-power precision machinery and control mechanisms that require compact structures and high transmission accuracy. The coupling consists of two hubs and a thin-walled metal tube, connected by either welding or bonding. Although many other materials are available, stainless steel and nickel are the most commonly used materials for the metal tube. Nickel tubes are produced using electrodeposition. This method first involves machining a solid mandrel into a corrugated shape, electroplating nickel onto the mandrel, and then chemically dissolving the mandrel to obtain the nickel bellows. This method allows for precise control of the bellows wall thickness and can achieve thinner walls than bellows made by other methods. These thin-walled bellows give the coupling high sensitivity and rapid response, making it ideal for applications in extremely small and precise instruments.

BILZ Coupling Introduction

It consists of two hubs and a thin-walled metal tube, connected by either welding or bonding. Although many other materials are available, stainless steel and nickel are the most commonly used materials for the metal tube. Nickel tubes are produced using electrodeposition. This method first involves machining a solid mandrel into a corrugated shape, electroplating nickel onto the mandrel, and then chemically dissolving the mandrel to obtain the nickel bellows. This method allows for precise control of the bellows wall thickness and can achieve thinner walls than bellows made by other methods. These thin-walled bellows give the coupling high sensitivity and rapid response, making it ideal for applications in extremely small and precise instruments.

BILZ Coupling Features and Applications

1) Bellows couplings are backlash-free and highly sensitive. 2) High elasticity provides better equipment protection. 3) Capable of absorbing vibration while strongly compensating for radial, angular, and axial misalignments. 4) Resistant to oil contamination and highly corrosion-resistant. 5) Torsionally rigid, with identical rotational characteristics in both clockwise and counter-clockwise directions. 6) Commonly used in industrial machinery such as CNC machine tools and indexing tables. The elastic element of a bellows coupling is a precision metal bellows, available in flexible and rigid series. The flexible series offers greater elasticity and is often used in miniature applications such as encoders and sensors, while the rigid series is mainly applied in servo motors and CNC machine tools (machining centers).

BILZ Coupling Troubleshooting

Based on the coupling structure, power is transmitted from the coupling to the power output shaft (gearbox shaft) via a clamping hub connection, and to the power input shaft via a clamp collar. Power transmission between the clamped end and the clamping hub end of the coupling is achieved through a bellows, which is bonded to both the clamping hub end and the clamp collar. The failure occurred at the interface between the clamp collar and the bellows. Two pre-deformation grooves are machined radially into the clamp collar. The groove width is approximately 2mm. One groove, located on the side with the clamping screw, is a through-slot in the diametrical direction but does not penetrate completely at the depth where it connects to the bellows; its cross-section is beveled. The other groove does not extend fully in the radial direction, nor does it penetrate completely at the longitudinal connection point with the bellows; its cross-section is also beveled. During clamping, the clamping screws are tightened to the specified torque using a torque wrench. This causes deformation of the clamp collar to eliminate clearance between the bore and the shaft, achieving a secure clamp. As shown in the cross-sectional view, the presence of the two pre-deformation grooves creates a weaker section, with deformation primarily occurring at these grooves. The pre-deformation groove on the side with the clamping screw has the smallest cross-sectional area and is therefore the weakest point. Permanent V-shaped deformation marks at its end indicate that the stress in this area during clamping exceeds the yield strength of the super-hard aluminum alloy. According to the stress distribution diagram, once the bevel gear box and main gearbox are assembled and clamped, the stress value at the bonded interface of the pre-deformation groove on the clamping screw side reaches 164Mpa, with a deformation magnitude of 0.027mm. During launcher operation, the coupling is subjected to alternating composite stresses, resulting in even higher stress and deformation at this location. If minor defects such as voids, inclusions, or flaws exist at the bonded interface during manufacturing, micro-cracks will initiate at these defective points within the region of highest stress on the coupling's bonded surface when the alternating stress exceeds the bond strength, forming fatigue initiation sites. Due to stress concentration at the crack tips, the cracks gradually propagate with increasing stress cycles and prolonged exposure to constant stress. As the cracks spread, the bonded interface is progressively weakened. When the cracks reach a critical size, fatigue failure occurs. Although the coupling functioned normally during initial testing, crack propagation over time leads to eventual failure, even under low loads. The presence of stress at the bonded joint is a latent cause of failure. To avoid excessive stress in the coupling clamp collar during clamping, annular relief grooves are typically machined into the clamp collar for stress relief.

Weidou Intelligent Technology specializes in selling German BILZ rigid couplings, BILZ flexible couplings, BILZ safety couplings, BILZ universal joints, BILZ disc couplings, BILZ jaw couplings, BILZ flange couplings, BILZ cross-slide couplings, BILZ slider couplings, BILZ gear couplings, BILZ tire couplings, BILZ elastic couplings, BILZ bellows couplings, BILZ roller chain couplings, and BILZ spring couplings. All products are original imports from Germany. Customers are welcome to inquire and place orders.