Cam-type One-way Clutch

One-way cam clutches use cams that engage between the input and output shafts to transmit torque (with engagement) in one direction and idle (without engagement) in the other direction. High torque is transmitted and engagement and idling are quickly switched in the customer's product whilst saving space.

Proven track record as a
one-way clutch manufacturer

More than half a century of experience and high reliability in mobility

Tsubaki has many years of experience as a manufacturer of one-way clutches and continues to develop new technologies. By using carefully selected optimum materials, our unique heat-treated cams, inner and outer races, high-precision machining using specialized machines, and thorough quality control have made it possible for us to produce a large number of products for general industrial use as well as for automobiles and motorcycles.

Tsubaki's strengths

Ability to make effective proposals
that meet the needs of our customers

Cams are the most critical part in determining the performance of the cam clutch. We use our many years of expertise in dimensional accuracy and hardness, as well as a wide variety of cams to ensure that it fulfills the role of a one-way clutch.

The basic structure of a product, in which our one-way clutch is adopted, determines its ability to meet the needs of customers. By understanding a wide variety of needs and products, Tsubaki's cam clutches will help you achieve your goals.


Extensive know-how condensed into
a simple structure

Cam clutches are composed of three main components: cams, cages and springs.
Cams are either delivered to customers pre-assembled with inner and outer races making up the raceway of the cams, or inner races may share a shaft, and outer races may share a casing, sprocket and pulley, etc.
In addition, a side plate may be used to support the axial load.

Function and operating principle

Relationship between input and output
during power transmission

Transmits torque in one direction only

The function of the cam clutch is to "transmit torque (T) in one direction only". This is made possible by the cam engaging between two rotating elements. At the same time, it also means there is “no cam engagement when torque transmission is unrequired.”

Assuming that the angular velocity in the engagement direction is positive, the relationship between input and output speeds during engagement and idling is as follows. Engagement : ωin = ωout , T >0
Idling : ωin < ωout , T =0
This characteristic allows for many modes of operation in a variety of applications.

Superior engagement responsiveness

Springs are the main components of cam clutches and provide moments in the direction of the cam engagement to allow the cams to engage at any time and instantly switch between static/idle and engaged states. This superior responsiveness eliminates almost all transmission losses of the cam clutches.

Mechanism of
energy loss reduction

Cam: High-speed engagement type
Cam: High-speed idling type

Minimize energy loss by using
centrifugal force

In order to maximize efficiency of our customers’ products, Tsubaki’s cam clutches are designed to minimize loss during power transmission. In accordance with customer needs, we offer two types of cams; one for high-speed engagement and the other for high-speed idling.

For high-speed engagement, the center of gravity of the cam is designed so that the cams engage with centrifugal force, enabling torque to be transmitted even at high speeds and reducing energy loss.

For high-speed idling, the centrifugal force lifts the cams up to prevent contact between the cams and surface of the inner race. This reduces energy loss by more than 90% at 1,700 r/min, and completely eliminates it at even higher speeds.


Two-speed drive

The combination of “engagement” and “idling” enables the power of multiple drive sources to be controlled freely.

Cam clutches engage when power transmission is required and idle when not by reversing the rotation.
This characteristic optimizes the output of the entire system by removing power from multiple drive sources in the area of highest efficiency.

Tsubaki offers two types; one uses speed difference (two-speed drive) and the other uses direction of rotation (dual drive).

We will propose the most suitable type according to the needs of the customer.


Prevents reverse load from the driven side and avoids damage to the drive source

Various types of motors are used in hybrid and electric vehicles. Motors drive the output side of vehicles, but if a large force is applied to the output side, they can become overloaded and damaged.

Tsubaki's cam clutches reduce energy loss when motors are running normally and prevent damage to the motor by instantly engaging when reverse input is applied to the motor shaft.

New products using
cam clutch technology

Under development Cam and Roller Clutch

Space-saving cam clutch with bearing function

Cam clutches are used in conjunction with bearings to ensure that all cams contribute equally to torque transmission. This product is currently being developed to meet customer needs of securing axial space despite having space in the outer diameter direction.

Details to be updated soon.

Under development Hybrid drive unit

Tsubaki’s unique drive unit that maximizes chain and cam clutch features

When extracting output from multiple drive sources, an external control device is typically required to switch the sources. This prevents customers from maximizing the benefits of efficiency by using multiple drive sources.

The advantages of Tsubaki's hybrid drive unit are:

  1. Deceleration mechanism to extract large output from a
    small motor
  2. No clutch control is required when switching drive sources,
    and the drive source speed can be controlled according to
    the desired output characteristics
  3. Simple structure of chain, sprocket and cam clutch

Details to be updated soon.