Vehicle transmission systems, cooling systems, and braking systems often use clutches or like devices to selectively transmit rotational forces from a drive shaft to an output member. Conventional clutch devices include an opposing pair of engagement surfaces that can be compelled toward or away from one another using an electrical, mechanical, pneumatic, or hydraulic actuation system. In general, the actuation system causes some relative axial shifting within the clutch device. Such axial movement is used to engage (or disengage) the opposing engagement surfaces, which rotationally interconnects (or rotationally disconnects) the drive shaft and the output member.
In clutch devices using pneumatic or hydraulic actuated systems, a piston may be acted upon by a set of springs to bias the piston toward one of the engaged or disengaged positions. Fluid pressure may act upon the piston, in a direction opposite to that of the spring force, to cause the piston portion to be axially shifted. Such axial movement is used to engage (or disengage) the opposing engagement surfaces, thus selectively controlling the rotation between the drive shaft and the output member.
Clutch devices may require repair or replacement if the engagement surfaces have worn beyond their useful life or if a component is not properly functioning. For instance, seals and clutch engagement surfaces may wear over time and require replacement.
The design of the clutch device can have a significant effect on the time and cost of repair or replacement of component parts. If a clutch device has multiple pieces that must be disassembled before the clutch device can be removed from the drive shaft, the labor costs associated with the repair or replacement of the clutch device may increase. In addition, if a clutch device includes components that are spring biased, extra tooling may be required to clamp those components in place as clutch device is disassembled or removed.
The location and number of seals such as O-rings in the clutch device may also affect the time and cost associated with repairing or replacing clutch devices. If a seal fails and starts to leak, the time required to locate which particular seal is broken may increase if the clutch device has a larger number of seals. Furthermore, the location of the seals may affect the likelihood of contaminants entering the fluid space. If a seal is disposed between two surfaces that move both axially and rotationally relative to one another, the seal may be more susceptible to leakage.
The longevity of the clutch device, and thus the repair interval, may be increased by reducing wear factors such as vibration. Clutch designs built with more liberal tolerances and clutch designs that allow greater degrees of inter-part vibration may have a shorter useful life.