The plum blossom coupling, also known as the jaw coupling, is a widely used elastic coupling composed of two metal shaft sleeves and an elastic plum blossom spacer. It has excellent balance performance and is suitable for high-speed scenarios, with a maximum speed of up to 30,000 revolutions per minute.
The plum blossom couplings are mainly divided into two types: the first is the traditional straight jaw type, and this type of coupling is not very suitable for servo drive systems with extremely high precision requirements; the second is the zero-gap coupling with a curved (concave) jaw type, which is developed on the basis of the straight jaw type and is especially suitable for servo system applications. Its curved surface design aims to reduce the deformation of the elastic plum blossom spacer and limit the influence of centripetal force on it during high-speed operation.
The zero-gap jaw-type plum blossom coupling is composed of two metal shaft sleeves (usually made of aluminum alloy, and stainless steel can also be provided) and a plum blossom elastic spacer. The plum blossom elastic spacer has multiple blade branches. By squeezing, the plum blossom elastic spacer closely adheres to the shaft sleeves on both sides, thereby ensuring its zero-gap performance and achieving squeeze transmission.
When using the zero-gap jaw-type coupling, users must be careful not to exceed the maximum load-bearing capacity of the elastic element specified by the manufacturer (under the premise of ensuring zero gap). Otherwise, the plum blossom elastic spacer will be flattened and deformed, lose elasticity, the preload will also disappear, resulting in the loss of zero-gap performance. In severe cases, it may take a long time for the user to notice after the problem occurs.