A one-way bearing is a type of bearing that is free to rotate in one direction and lock in the other direction. One-way bearings are also called overrunning clutches, but are named according to different industries and different functions. The metal casing of a one-way bearing contains a large number of rollers, needles or balls, and its rolling seat (hole) is shaped so that it can only roll in one direction and a large resistance in the other direction ( The so-called "one-way").
Introduction
Powder metallurgy one-way bearings use a molding and sintering process to form a metal powder (or a mixture of metal powder and non-metal powder) into a product. On the basis of studying the characteristics of the powder and the characteristics of the process change, the corresponding technical processes are used to change the shape, properties and their structure of the powder to become a bearing product to meet different needs.
The solid one-way bearing uses GCr15 bearing steel, the hardness after heat treatment is HRC61-65, the bearing volume is small and has high bearing capacity, there is enough space for storing grease, and there is a longer lubrication interval.
The powder metallurgy one-way bearing and the solid one-way bearing can completely "lock" the drive shaft when it is driven by the driving force, thereby avoiding the problem of insufficient "locking" performance of the conventional one-way bearing of the drawn outer ring.
Main uses: textile machinery; printing machinery; automotive industry; household appliances; currency detectors.
HF series one-way needle roller bearings: consisting of a stamped outer ring and a plastic cage. The cage can be equipped with a plastic reed or a stainless steel reed to guide the needle, and the beveled raceway and needle on the outer ring are used as locking devices. . HFL (clutch and bearing assembly): The support bearings are mounted on both sides of the needle clutch and are subjected to radial loads. The support bearings are needle roller and plastic cage assemblies. Since there is no inner ring, the wear on the shaft is large, so it is best to heat treat the shaft.
model
One-way bearings: HF, HFL, FC, FCB, RCB, RC, F, IWC, EWC, DC, CSK, CKB (B200), ASNU, CKA, FWD, NF, etc.
Technical principle
A one-way bearing is a type of bearing that is free to rotate in one direction and lock in the other direction. The metal casing of a one-way bearing contains a large number of rollers, needles or balls, and its rolling seat (hole) is shaped so that it can only roll in one direction and a large resistance in the other direction.
The working principle of the one-way bearing:
1. Wedge design This wedge type one-way overrunning clutch is generally composed of inner ring, outer ring, wedge group, wedge cage, strong spring and bearing. The wedge transfers forces from one raceway to the other by wedging between the inner and outer races. The wedge has two diagonal diameters (ie, the distance from one corner of the wedge to the other diagonal) one of which is larger than the other. The wedge action forces the wedge to have a larger vertical position on a relatively large cross section when the inner and outer rings are rotated relative to each other.
2. The self-locking angle wedge mainly relies on the wedge and self-locking angle of the wedge between the inner and outer rings.
The basic concept of a wedge one-way clutch requires that the friction coefficient of the wedge be related to the sudden generation of torque in the inner ring in the drive direction. This friction value must be greater than the tangent of the self-locking angle. If the condition is not safe, the wedge will not occur. The self-locking angle is determined by the structure of the wedge, and the points on the inner and outer rings are respectively connected by wedges. The design of the wedge has a very low initial self-locking angle to ensure absolute bonding at the beginning. As the torque increases, a radial force will be created on the wedge that deflects the wedge race, causing the wedge to roll to a new position. Wedges are often designed to have a self-locking angle that can be gradually increased, as it goes from the overrun position to the maximum load bearing position. A relatively large self-locking angle can reduce the radial force generated by the wedge, so that a large torque is allowed to be transmitted as long as the elongation and Brinell hardness limits are required.
3. Slope and roller design
The ramp and roller one-way clutch consists essentially of an outer ring of cylindrical inner diameter, an inner ring with a ramp, and a set of rollers that are respectively spring-loaded and in close contact with the inner and outer rings. As long as the rotation of one of the raceways in its direction of motion has an effect on the other, this arrangement essentially ensures the instantaneousness of the speed of overrun and ensures immediate drive capability.
This type of one-way clutch can be used for overtaking, indexing and non-reversal in various environments. When used as an overrunning one-way clutch, the sloping roller type one-way clutch will be installed in such a way that the outer ring is used as a transmissive member. This is very important for high speed overtaking. In the application of the inner ring transcendence, the centrifugal force acting on the roller will result in a limited speed of overrun.
When used as a non-return one-way clutch, a ramp-type one-way clutch with only inner ring rotation is suitable for relatively low speeds. If the required speed is higher than the recommended speed, a wedge type one-way clutch is recommended. When used as an indexing one-way clutch, the outer ring is often seen as a wobble element and the inner ring is often seen as a slave element. Otherwise, the inertia of the rollers and springs will cause errors, especially at high frequency divisions. The use of diluted lubricants and powerful springs provides high-speed indexing accuracy and high quality.