Brake & Clutch Power Transmission Engineering

Power transfer through a clutch or brake is the method by which the energy is transferred from one rotating device to a second non-rotating device. In the case of a clutch, the second non-rotating device is brought up to the same rotational speed as the driving device. In a brake, the second non-rotating device is fixed, and the driving device is gradually brought to a stop. The end result is that both devices are rotating at the same speed (or in the case of a brake are completely stopped). The two common methods of engagement are friction and jaw (or tooth).

The friction and the jaw engagement methods are available in any version of actuation method selected. For example Carlyle Johnson offers a spring-engaged clutch. The spring engaged clutch is available with single or multiple disc friction surfaces or a jaw type torque transfer system.

Clutch and Brake Power Transfer

Type Summary
Friction Uses friction discs to transfer torque between rotating/non-rotating parts
Jaw / Tooth Uses serrated tooth design to transfer torque from rotating part to non-rotating part

Friction Clutches and Brakes

Friction clutches and brakes utilize friction discs to transfer the energy from one rotating member to a second rotating member. The friction between the discs of the two bodies allows the clutch or brake to transmit torque. The friction discs are flat smooth surfaces that are alternately attached to the rotating and the non-rotating elements. The sequence and type of friction surface, as well as the load presented to the clutch/brake will determine the size and number of friction surfaces that are utilized to transmit the torque.

Once the torque capacity of the disc friction surfaces is exceeded then the device will slip. It will also slip during engagement and disengagement, while the friction discs are being gradually squeezed together by whatever actuation method is used. This allows a smooth transfer of torque from one device to another. Learn more about Friction Power Transfers.

Jaw (or Tooth) Clutches and Brakes

Jaw clutches and brakes utilize a serrated tooth design to transfer or absorb energy from one rotating device to a second rotating device. The friction between the surfaces of the teeth of the rotating and non-rotating device allows the clutch to transmit torque or a brake to hold a device in a stopped condition. Learn more about Jaw or Tooth Power Transfers.

Power Transfer Summary

Each method of power transfer offers the designer some advantages and disadvantages. It is important to realize what these advantages are when selecting a clutch or a brake. This is only a general guide and there are always exceptions. Carlyle Johnson has the expertise to resolve the most difficult control problems.

Problem Carlyle Solution Type
Dust, Usage Wear Advanced Composite Friction Surfaces Friction
High Torque Wear Multiple Pressure-Angle Jaw Configurations Jaw or Tooth
Backlash Zero Backlash Jaw Tooth Designs Jaw or Tooth

Examples of design variations developed by the engineers at Carlyle Johnson include the use of advanced composite friction surfaces for dust free and virtually zero wear usage, as well as complex multiple pressure-angle jaw configurations to assure positive disengagement in very high torque applications. Some positioning brakes have virtually zero "backlash". Carlyle Johnson has developed jaw tooth designs for many precision-indexing applications.

Occasionally the requirement for an application with a manual override will result in the use of several different power transmission devices either in tandem or within a single housing, permitting continued operation in the event of power or prime mover failure. Friction-type devices have been designed to permit bi-directional driving by an electric motor but allowing no backdrive, resulting in a safety brake which prevents the driven load from moving, until power is restored. The locking action during power failure can assure a condition with "no stored energy" reducing risks of accidents and injuries to personnel.

There are thousands of such custom applications where Carlyle Johnson has solved unique and difficult power transmission problems. Factors such as weight and size limitations, environment, special materials, service life, accessibility, engagement speed, and cost constraints are challenges we can meet with our expertise and long history. Our clutches and brakes work in outer space and at ocean depths of 15,000 feet. Consult us for further information on your power transmission applications.


Types of Power Transfer

Advantages of Friction engagement

  • Soft engagement of devices to be coupled
  • Engagement speed is not limited

Advantages of Jaw/Tooth engagement

  • High torque in a relatively small size
  • Capable of indexing or registration of input to output
  • Positive engagement of teeth allowing virtually zero backlash

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