Discussion Overview
The discussion revolves around determining the force required to hold a pneumatic piston stationary during assembly, specifically in the context of preventing rotation while a torque is applied. Participants explore various mechanical considerations and approaches related to clamping and torque application.
Discussion Character
- Technical explanation
- Debate/contested
- Experimental/applied
Main Points Raised
- One participant inquires about the force needed to hold a piston in place against a torque of 50 Nm, questioning if the formula T-rfsin(theta) is applicable.
- Another participant mentions using a pneumatic piston to exert the necessary force.
- Some participants assert that torque cannot be applied to a piston, only linear force, and request clarification on the mechanism involved.
- A participant explains the context of assembling an oil pump, detailing how the piston is clamped pneumatically to prevent rotation while components are tightened with a torque wrench.
- Concerns are raised about the lubrication of the piston-clamp interface, with one participant suggesting that the coefficient of friction should be determined experimentally.
- Another participant states that the tangential force required to stop the piston from rotating is equal to the applied torque divided by the piston radius, emphasizing the need for the coefficient of friction to calculate clamping force.
- Some participants propose alternative methods to prevent rotation, such as using a hollow gudgeon pin or internal tooling, rather than external clamping.
- One participant mentions the challenges of creating a universal fixture for various piston designs, noting that not all pistons have a through hole for clamping.
- Concerns about maintaining the external finish of the piston are discussed, with suggestions for using adapter pins for different sizes to avoid damage.
Areas of Agreement / Disagreement
Participants express differing views on the applicability of torque to the piston and the best methods for clamping it without causing damage. The discussion remains unresolved, with multiple competing approaches and considerations presented.
Contextual Notes
Limitations include the need for specific coefficients of friction, which are suggested to be determined experimentally, and the varying dimensions of piston holes complicating the clamping process.
