Cálculo de tolerancias ajuste agujero y eje

Summary

This video explains the process of calculating tolerances for a mechanical fit between a hole and a shaft. The script outlines the steps for determining the diameter, tolerance, and fit type for both parts based on ISO standards. It covers the importance of quality and position tolerances, explains how to calculate the maximum and minimum diameters for the hole and shaft, and identifies the type of fit (clearance fit) through a series of calculations. The final result provides a comprehensive understanding of the tolerances and fit, making it valuable for engineering applications.

Takeaways

• 😀 The script discusses the calculation of tolerances and fits for a hole and shaft assembly.
• 😀 The nominal diameter for both the hole and shaft is 40 mm, based on ISO tolerance standards.
• 😀 The hole tolerance is indicated as 'H7', with the capital 'H' signifying the hole type and '7' referring to the quality of the tolerance.
• 😀 Tolerances are calculated using a table, where a quality value of 25 microns (0.025 mm) is used for the hole.
• 😀 The position of the tolerance for the hole is zero, meaning it lies on the baseline (0), leading to a calculated maximum diameter of 40.025 mm.
• 😀 The shaft has a tolerance of '6', indicating a tolerance of 16 microns (0.016 mm) from a table.
• 😀 The position of the tolerance for the shaft is calculated as -9 microns, leading to a minimum diameter of 39.975 mm.
• 😀 The type of fit (clearance or interference) is determined by comparing the minimum diameter of the hole and the maximum diameter of the shaft.
• 😀 If the minimum hole diameter is greater than the maximum shaft diameter, a clearance fit is present.
• 😀 The maximum and minimum play (clearance) between the hole and shaft are calculated, with values of 0.050 mm (50 microns) and 0.009 mm (9 microns) respectively.
• 😀 The total tolerance for the assembly is calculated by adding the tolerances of the hole and the shaft, resulting in a total tolerance of 41 microns.

Q & A

What does '40 H7' refer to in the context of the adjustment?

In this context, '40 H7' represents the nominal diameter of the hole, with '40' being the nominal diameter in millimeters and 'H7' indicating the position and quality of the tolerance for the hole.

What is the significance of the 'H' in 'H7' for the hole tolerance?

The 'H' indicates the tolerance position, which defines the deviation limits for the hole. It tells us that the lower deviation is zero, meaning the hole size cannot be smaller than the nominal size.

What role does the number '7' play in 'H7' tolerance?

The number '7' represents the tolerance quality, specifying the range or interval of allowable deviation for the hole's size. In this case, '7' corresponds to a tolerance of 25 microns (0.025 mm) as per the relevant standard tables.

How are the tolerances for the hole calculated?

The tolerances for the hole are calculated by combining the position tolerance (which in this case is zero) and the quality of tolerance (25 microns or 0.025 mm), resulting in the maximum and minimum diameters for the hole.

How do we calculate the maximum and minimum diameters of the hole?

The maximum diameter of the hole is calculated by adding the tolerance to the nominal diameter, while the minimum diameter is calculated by subtracting the tolerance. In this case, the maximum diameter is 40.025 mm and the minimum diameter is 40.000 mm.

What is the significance of the quality tolerance (25 microns) for the hole?

The quality tolerance of 25 microns indicates the permissible deviation range for the hole size. It directly affects the final size, and in this case, the allowable variation is 0.025 mm above or below the nominal 40 mm size.

How is the tolerance for the shaft (eje) determined?

The tolerance for the shaft is determined in a similar way, using the diameter and the tolerance position. For the shaft with a nominal diameter of 40 mm and tolerance '6', the quality tolerance is found to be 16 microns (0.016 mm), and the position tolerance is -9 microns.

Why is the position tolerance for the shaft negative?

The position tolerance for the shaft is negative because the shaft tolerance is located below the zero line in the tolerance chart, indicating that the shaft's diameter is slightly smaller than the nominal diameter.

What does the term 'interference fit' refer to in the context of the adjustment?

An interference fit occurs when the minimum diameter of the hole is larger than the maximum diameter of the shaft, creating a tight fit where the parts will not slide together easily. In this case, the condition indicates that the hole will have a slightly larger diameter than the shaft.

How is the maximum and minimum fit (play) calculated for the hole and shaft?

The maximum play is calculated by subtracting the minimum diameter of the shaft from the maximum diameter of the hole, and the minimum play is calculated by subtracting the maximum diameter of the shaft from the minimum diameter of the hole. For this case, the maximum play is 0.050 mm and the minimum play is 0.009 mm.