Device and method to improve as-cast inner surface quality in cast parts

Abstract

A flexible grinder device and method for cleaning an as-cast inner hole surface using the flexible grinder device is provided. The flexible grinder device includes a hydraulic motor powered by a fluid; a control module in communication with the hydraulic motor; a flexible pressure vessel coupled to the hydraulic motor; and an abrasive layer coupled to an outer surface of the flexible pressure vessel. The flexible pressure vessel is configured to contain the fluid, and the fluid is configured to be pressurized. The flexible pressure vessel is rotatable by the hydraulic motor, and the flexible pressure vessel is conformable with an as-cast inner hole surface.

Description

INTRODUCTION

[0001] The present invention relates to the field of machining and finishing tools, and more particularly to a flexible tool designed for cleaning inner surfaces of lightening holes in as-cast metal parts.

[0002] Metal parts, for example crankshafts, are critical components in internal combustion engines for converting linear piston motion into rotational motion. To reduce weight and improve performance, crankshafts often feature lightening holes. These holes, typically cast into the crankshaft, require precise finishing to ensure optimal performance and longevity. Traditional methods for cleaning and grinding these inner surfaces involve rigid tools that may not conform to the irregular shapes and sizes of the lightening holes, leading to incomplete cleaning and inconsistent surface finishes.

[0003] Thus, there is a need for new and improved techniques that offer capability and improved efficiency and quality products to clean inter hole surfaces.SUMMARY

[0004] According to several aspects of the present disclosure, a flexible grinder device is provided. The flexible grinder device includes a hydraulic motor powered by a fluid; a control module in communication with the hydraulic motor; a flexible pressure vessel coupled to the hydraulic motor; and an abrasive layer coupled to an outer surface of the flexible pressure vessel. The flexible pressure vessel is configured to contain the fluid, and the fluid is configured to be pressurized. The flexible pressure vessel is rotatable by the hydraulic motor, and the flexible pressure vessel is conformable with an as-cast inner hole surface.

[0005] In accordance with another aspect of the disclosure, the fluid includes at least one of air or water.

[0006] In accordance with another aspect of the disclosure, the flexible pressure vessel is formed from at least one of a carbon-fiber based composite, rubber, or a polymer-based material.

[0007] In accordance with another aspect of the disclosure, the flexible pressure vessel is formed from an air-tight fabric.

[0008] In accordance with another aspect of the disclosure, the flexible pressure vessel is tube-shaped.

[0009] In accordance with another aspect of the disclosure, the flexible pressure vessel is configured to withstand a pressure between 10 and 50 pounds per square inch (psi).

[0010] In accordance with another aspect of the disclosure, the flexible pressure vessel is between 0.3 and 1.5 millimeters (mm) in thickness.

[0011] In accordance with another aspect of the disclosure, the flexible pressure vessel is rotatable between 500 and 2000 rotations per minute (rpm).

[0012] In accordance with another aspect of the disclosure, the abrasive layer is between 0.1 and 0.3 millimeters (mm) in thickness.

[0013] In accordance with another aspect of the disclosure, the abrasive layer includes abrasive particles formed from at least one of aluminum oxide (Al2O3) or silicon carbide (SiC).

[0014] In accordance with another aspect of the disclosure, the abrasive layer includes abrasive particles with an average mesh screen size between 200 and 3000.

[0015] In accordance with another aspect of the disclosure, the flexible grinder device further comprises a sealant layer disposed on the flexible pressure vessel and configured to make the flexible pressure vessel at least one of air-tight or water-tight.

[0016] According to several aspects of the present disclosure, a flexible grinder device is provided. The flexible grinder device includes a hydraulic motor powered by a fluid including at least one of air or water, a control module in communication with the hydraulic motor, a flexible pressure vessel coupled to the hydraulic motor, and an abrasive layer coupled to an outer surface of the flexible pressure vessel. The flexible pressure vessel is configured to contain the fluid, and the fluid is configured to be pressurized. The flexible pressure vessel is rotatable by the hydraulic motor, and the flexible pressure vessel is conformable with an as-cast inner hole surface. The flexible pressure vessel is configured to withstand a pressure between 10 and 50 pounds per square inch (psi).

[0017] In accordance with another aspect of the disclosure, the flexible pressure vessel is formed from at least one of a carbon-fiber based composite, rubber, or a polymer-based material.

[0018] In accordance with another aspect of the disclosure, the flexible pressure vessel is between 0.3 and 1.5 millimeters (mm) in thickness.

[0019] In accordance with another aspect of the disclosure, the flexible pressure vessel is rotatable between 500 and 2000 rotations per minute (rpm).

[0020] In accordance with another aspect of the disclosure, the abrasive layer is between 0.1 and 0.3 millimeters (mm) in thickness.

[0021] In accordance with another aspect of the disclosure, the abrasive layer includes abrasive particles with an average mesh screen size between 200 and 3000.

[0022] According to several aspects of the present disclosure, a method for cleaning an as-cast inner hole surface using a flexible grinder device is provided. The method includes ushering a flexible pressure vessel of the flexible grinder device into an as-cast inner hole, pressurizing the flexible pressure vessel with the fluid so that the flexible pressure vessel flexibly conforms to the as-cast inner hole surface, and rotating the flexible pressure vessel using the hydraulic motor. The flexible pressure vessel is mechanically and fluidly coupled to a hydraulic motor powered by a fluid. Additionally, an abrasive layer is disposed on an outer surface of the flexible pressure vessel, and the abrasive layer cleans the as-cast inner hole surface as the flexible pressure vessel rotates.

[0023] In accordance with another aspect of the disclosure, the method further comprises shot peening the as-cast inner hole surface.

[0024] The above features and advantages, and other features and advantages, of the presently disclosed system and method are readily apparent from the detailed description, including the claims, and examples when taken in connection with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present disclosure will become more fully understood from the detailed description and the accompanying drawings.

[0026] FIG. 1 is a schematic side view illustrating a flexible grinder device, where the flexible grinder device includes a flexible pressure vessel, in accordance with the present disclosure.

[0027] FIG. 2 is a partial cross section view illustrating a portion of the flexible pressure vessel shown in FIG. 1, wherein the flexible pressure vessel has an abrasive layer coupled to an outer surface of the flexible pressure vessel, in accordance with the present disclosure.

[0028] FIG. 3 is a schematic view illustrating the flexible grinder device shown in FIG. 1 inserted into a lightening hole, wherein the flexible pressure vessel is in a pressurized state, in accordance with the present disclosure.

[0029] FIG. 4 is a flowchart illustrating a method for cleaning an as-cast inner hole surface using the flexible grinder device shown in FIGS. 1 through 3, in accordance with the present disclosure.DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, summary, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0031] Reference will now be made in detail to several examples of the disclosure that are illustrated in accompanying drawings. Whenever possible, the same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0032] Rough as-cast surfaces of castings compromise their fatigue durability substantially. Cored lightening hole surfaces have conventionally remained in service as-cast because of difficulty of accessibility by available cleaning or machining tools (e.g., brushes, water jets, turning, etc.), in the case of cast crankshafts made of a cast steel or nodular iron. Thus, inner hole surfaces have become susceptible locations to a premature fatigue failure.

[0033] A flexible grinder device and method is disclosed herein and is designed to provide an efficient and reliable solution for cleaning and grinding inner surfaces of lightening holes and other spaces in metal parts, for example cast ferrous alloy crankshafts (e.g., a nodular iron crankshaft). The flexible grinder device has flexibility that allows conformation with varying geometries of the inner surface of lightening holes, ensuring thorough cleaning and consistent surface finishes. This adaptability reduces the risk of surface defects and stress concentrations, thereby enhancing the fatigue durability of the crankshaft. The flexible grinder device and method disclosed herein remove rough asperities, scales, and possible inclusions on the as-cast inner surfaces. The flexible grinder device and method are also capable of grinding off degenerated graphite skin as needed so that a uniform casting property can be maintained in the casting from surface to matrix, therefore improving the casting’s fatigue endurance and robustness.

[0034] FIG. 1 illustrates a flexible grinder device 10. The flexible grinder device 10 includes a hydraulic motor 12, a control module 14 in communication with the hydraulic motor 12, a flexible pressure vessel 16 coupled to the hydraulic motor 12, and an abrasive layer 18 coupled to the flexible pressure vessel 16. The flexible grinder device 10, and more specifically the flexible pressure vessel 16, may be ushered into an otherwise inaccessible space, for example a lightening hole, and rotated to clean an inner surface of the lightening hole and remove surface imperfections, for example scales, asperites, inclusions, and / or degenerated graphite skin.

[0035] As illustrated in FIG. 1, the flexible grinder device 10 includes a hydraulic motor 12 that is powered by a fluid, for example air (e.g., a pneumatic motor) or water (e.g., a hydraulic water motor). The air or water is compressed and / or pressurized and fed into the hydraulic motor 12 via an inlet 20. The hydraulic motor 12 includes a mechanical actuator that converts hydraulic pressure and flow from the fluid into torque and angular displacement (rotation). The hydraulic motor 12 may include sensors or gauges to monitor a fluid pressure in the flexible pressure vessel 16.

[0036] A control module 14 is in communication with and controls the hydraulic motor 12. The control module 14 regulates operation of the hydraulic motor 12 to ensure precise and consistent performance. The control module 14 may include sensors and / or feedback mechanisms to monitor the operation of the hydraulic motor 12 and adjust speed and / or performance of the hydraulic motor 12 as needed.

[0037] The flexible pressure vessel 16 is mechanically and fluidly coupled to the hydraulic motor 12 and is designed to contain the pressurized fluid 22 (e.g., air, water). The flexible pressure vessel 16 is capable of rotating under the power of the hydraulic motor 12 and is designed to conform to the irregular shapes and sizes of the as-cast inner hole surfaces (e.g., of lightening holes in crankshafts or other cast parts). This flexibility allows the flexible pressure vessel 16, when ushered into a lightening hole, for example, to adapt to varying geometries of the lightening holes, ensuring thorough cleaning and consistent surface finishes. The flexible pressure vessel 16 may be constructed from materials that provide the necessary flexibility and durability, such as reinforced elastomers or composite materials (e.g., an air-tight fabric, a carbon-fiber based composite, rubber, a polymer-based material, a polymer film, and the like). The flexible pressure vessel 16 itself may function as an abrasive without an additional polishing medium attached. In one example, the flexible pressure vessel 16 is formed from an air-tight fabric having a thickness between 0.3 and 1.5 millimeters (mm) in thickness. One of skill in the art would understand the meaning of the term “about.” Alternatively, the term “about” means plus or minus 0.05 mm. In another example, the flexible pressure vessel 16 is hose or tube-shaped. In yet another example, the flexible pressure vessel 16 is configured to withstand a pressure between 10 and 50 pounds per square inch (psi) and have a limited leak rate. The flexible pressure vessel 16 may be rotatable between 500 and 2000 rotations per minute (rpm). Additionally, a length of the flexible pressure vessel 16 may be selective or variable so that a single cast part or multiple cast parts may be simultaneously cleaned.

[0038] As illustrated in FIG. 2, an abrasive layer 18 is coupled to an outer surface of the flexible pressure vessel 16. FIG. 2 illustrates a portion of the flexible pressure vessel as shown in FIG. 1. The abrasive layer 18 functions to grind and clean an inner surface of the lightening holes, removing surface defects and ensuring a smooth and consistent surface finish. The abrasive layer 18 may be composed of materials such as aluminum oxide (Al2O3), diamond grit, silicon carbide (SiC), or other suitable abrasives that provide effective material removal and long-lasting performance. The abrasive layer 18 may be bonded to the flexible pressure vessel 16 using an adhesive binder, for example a glue or a resin. The abrasive layer 18 may include abrasive particles or grains distributed over the adhesive binder and the flexible pressure vessel 16 to form the abrasive layer 18. In one example, the abrasive layer may be between 0.1 and 0.3 millimeters (mm) in thickness. In one example, the abrasive layer may include abrasive particles with an average mesh screen size between 200 and 3000.

[0039] In some instances, the flexible grinder device 10 may include a sealant layer 26 disposed on the flexible pressure vessel. The sealant layer 26 is configured to make the flexible pressure vessel 16 air-tight and / or water-tight. In an example, the sealant layer 26 may include a polyurethane-based fabric sealant, which can provide flexibility, durability, and resistance to water and chemicals. It will be appreciated that the sealant layer 26 may include a variety of other suitable sealants.

[0040] As illustrated in FIG. 3, the flexible grinder device 10 may be ushered into a lightening hole 28 or other irregularly shaped space to clean and provide a finish to the corresponding cast part. In FIG. 3, the flexible pressure vessel 16 is shown as being ushered into the lightening hole 28 of, for example, a journal section 30 of an engine crankshaft. The flexible pressure vessel 16 is configured to receive pressurized fluid (e.g., air, water, and the like) and apply a normal force against and rigidly contact the inner surface 32 of the as-cast surface of the journal section 30. The flexible pressure vessel 16 is then configured to be rotated by the hydraulic motor 12 and function as a grinder. The abrasive layer 18, disposed on an outside surface of the flexible pressure vessel 16 cleans, removes, and / or grinds the inner surface 32.

[0041] In operation, the flexible grinder device 10 is inserted into the lightening hole 28 of a crankshaft or a space in another cast part (e.g., journal section 30). The hydraulic motor 12 is activated causing the flexible pressure vessel 16 to rotate. Pressurized fluid 22 within the flexible pressure vessel 16 allows the flexible pressure vessel 16 to expand and conform to the inner surface 32 of the lightening hole 28. As the flexible pressure vessel 16 rotates, the abrasive layer 18 grinds and cleans the inner surface 32, removing any surface defects and ensuring a smooth and consistent finish. The control module 14 monitors the operation of the hydraulic motor 12 and adjusts performance as needed to ensure optimal cleaning and grinding of the inner surface 32.

[0042] With reference to FIG. 4, a method 100 for cleaning an as-cast inner hole surface using the flexible grinder device 10 shown in FIGS. 1 through 3 is presented, in accordance with the present disclosure. The method 100 starts at step 102.

[0043] Step 102 depicts ushering the flexible pressure vessel 16 of the flexible grinder device 10 into an as-cast inner hole (e.g., lightening hole 28). Ushering the flexible pressure vessel 16 may include using a robot, for example, to usher the flexible pressure vessel 16 when the flexible pressure vessel 16 has little and / or no fluid or pressure. In this way, the flexible pressure vessel 16 can be flexible and / or pliable and be configured to conform to a geography of the inner surface 32 of the as-cast inner hole (e.g., lightening hole 28).

[0044] Step 104 depicts pressurizing the flexible pressure vessel 16 with the fluid 22 so that the flexible pressure vessel 16 flexibly conforms to the as-cast inner hole surface (e.g., inner surface 32). Pressurizing the flexible pressure vessel 16 may include using the hydraulic motor 12 to supply the fluid 22. For example, the hydraulic motor 12 may include a pneumatic motor that provides a supply of pressurized air to the flexible pressure vessel 16, where the flexible pressure vessel 16 becomes rigid or semi-rigid and conforms to the as-cast inner hole surface (e.g., inner surface 32). It is contemplated that pressurizing the flexible pressure vessel 16 may also include using, for example, using a hydraulic motor 12 that uses water or another liquid.

[0045] Step 106 depicts rotating the flexible pressure vessel 16 using the hydraulic motor 12. The hydraulic motor 12 may be used to rotate the flexible pressure vessel 16 when pressurized with fluid to clean, remove, and / or grind the inner surface 32. The control module 14 may be used to cause the hydraulic motor 12 to rotate, and the control module 14 may be used to determine a rate or duration of rotation of the flexible pressure vessel 16.

[0046] Step 108 depicts shot peening the as-cast inner hole surface (e.g., inner surface 32). Shot peening may include bombarding the inner surface 32 with small spherical media, for example steel, to enhance mechanical properties of the inner surface 32. Each particle of spherical media acts similar to a tiny hammer and creates small indentations and a compressive residual stress layer on the inner surface 32, which prevents microcracks forming or spreading on the inner surface 32. The shot peening may be performed using a compressed air or a wheel turbine.

[0047] The flexible grinder device 10 and method 100 of the present disclosure is advantageous and beneficial over the prior art. A need for a more efficient, flexible, and reliable tool for cleaning and grinding the inner surfaces of lightening holes in cast ferrous alloy crankshafts has led to the development of the flexible grinder device 10. The flexible grinder device 10 aims to address the limitations of current methods by providing a tool that can adapt to the varying geometries of lightening holes or other tight or uneven spaces ensuring thorough cleaning and consistent surface finishes while reducing the risk of damage to the crankshaft or other cast part. The combination of the flexible pressure vessel 16 and the abrasive layer 18 provides an efficient and reliable solution for finishing the inner surfaces 32 of lightening holes and other irregular or hard-to-reach spaces in as-cast parts (e.g., ferrous alloy crankshafts). The adaptability of the flexible pressure vessel 16 reduces the risk of surface defects and stress concentrations, thereby enhancing the fatigue durability of the crankshaft / cast part.

[0048] This description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims.

Examples

Embodiment Construction

[0030]The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, summary, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0031]Reference will now be made in detail to several examples of the disclosure that are illustrated in accompanying drawings. Whenever possible, the same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0032]Rough as-cast surfaces of castings compromise their fatigue durability sub...

INTRODUCTION

[0001] The present invention relates to the field of machining and finishing tools, and more particularly to a flexible tool designed for cleaning inner surfaces of lightening holes in as-cast metal parts.

[0002] Metal parts, for example crankshafts, are critical components in internal combustion engines for converting linear piston motion into rotational motion. To reduce weight and improve performance, crankshafts often feature lightening holes. These holes, typically cast into the crankshaft, require precise finishing to ensure optimal performance and longevity. Traditional methods for cleaning and grinding these inner surfaces involve rigid tools that may not conform to the irregular shapes and sizes of the lightening holes, leading to incomplete cleaning and inconsistent surface finishes.

[0003] Thus, there is a need for new and improved techniques that offer capability and improved efficiency and quality products to clean inter hole surfaces.SUMMARY

[0004] According to several aspects of the present disclosure, a flexible grinder device is provided. The flexible grinder device includes a hydraulic motor powered by a fluid; a control module in communication with the hydraulic motor; a flexible pressure vessel coupled to the hydraulic motor; and an abrasive layer coupled to an outer surface of the flexible pressure vessel. The flexible pressure vessel is configured to contain the fluid, and the fluid is configured to be pressurized. The flexible pressure vessel is rotatable by the hydraulic motor, and the flexible pressure vessel is conformable with an as-cast inner hole surface.

[0005] In accordance with another aspect of the disclosure, the fluid includes at least one of air or water.

[0006] In accordance with another aspect of the disclosure, the flexible pressure vessel is formed from at least one of a carbon-fiber based composite, rubber, or a polymer-based material.

[0007] In accordance with another aspect of the disclosure, the flexible pressure vessel is formed from an air-tight fabric.

[0008] In accordance with another aspect of the disclosure, the flexible pressure vessel is tube-shaped.

[0009] In accordance with another aspect of the disclosure, the flexible pressure vessel is configured to withstand a pressure between 10 and 50 pounds per square inch (psi).

[0010] In accordance with another aspect of the disclosure, the flexible pressure vessel is between 0.3 and 1.5 millimeters (mm) in thickness.

[0011] In accordance with another aspect of the disclosure, the flexible pressure vessel is rotatable between 500 and 2000 rotations per minute (rpm).

[0012] In accordance with another aspect of the disclosure, the abrasive layer is between 0.1 and 0.3 millimeters (mm) in thickness.

[0013] In accordance with another aspect of the disclosure, the abrasive layer includes abrasive particles formed from at least one of aluminum oxide (Al2O3) or silicon carbide (SiC).

[0014] In accordance with another aspect of the disclosure, the abrasive layer includes abrasive particles with an average mesh screen size between 200 and 3000.

[0015] In accordance with another aspect of the disclosure, the flexible grinder device further comprises a sealant layer disposed on the flexible pressure vessel and configured to make the flexible pressure vessel at least one of air-tight or water-tight.

[0016] According to several aspects of the present disclosure, a flexible grinder device is provided. The flexible grinder device includes a hydraulic motor powered by a fluid including at least one of air or water, a control module in communication with the hydraulic motor, a flexible pressure vessel coupled to the hydraulic motor, and an abrasive layer coupled to an outer surface of the flexible pressure vessel. The flexible pressure vessel is configured to contain the fluid, and the fluid is configured to be pressurized. The flexible pressure vessel is rotatable by the hydraulic motor, and the flexible pressure vessel is conformable with an as-cast inner hole surface. The flexible pressure vessel is configured to withstand a pressure between 10 and 50 pounds per square inch (psi).

[0017] In accordance with another aspect of the disclosure, the flexible pressure vessel is formed from at least one of a carbon-fiber based composite, rubber, or a polymer-based material.

[0018] In accordance with another aspect of the disclosure, the flexible pressure vessel is between 0.3 and 1.5 millimeters (mm) in thickness.

[0019] In accordance with another aspect of the disclosure, the flexible pressure vessel is rotatable between 500 and 2000 rotations per minute (rpm).

[0020] In accordance with another aspect of the disclosure, the abrasive layer is between 0.1 and 0.3 millimeters (mm) in thickness.

[0021] In accordance with another aspect of the disclosure, the abrasive layer includes abrasive particles with an average mesh screen size between 200 and 3000.

[0022] According to several aspects of the present disclosure, a method for cleaning an as-cast inner hole surface using a flexible grinder device is provided. The method includes ushering a flexible pressure vessel of the flexible grinder device into an as-cast inner hole, pressurizing the flexible pressure vessel with the fluid so that the flexible pressure vessel flexibly conforms to the as-cast inner hole surface, and rotating the flexible pressure vessel using the hydraulic motor. The flexible pressure vessel is mechanically and fluidly coupled to a hydraulic motor powered by a fluid. Additionally, an abrasive layer is disposed on an outer surface of the flexible pressure vessel, and the abrasive layer cleans the as-cast inner hole surface as the flexible pressure vessel rotates.

[0023] In accordance with another aspect of the disclosure, the method further comprises shot peening the as-cast inner hole surface.

[0024] The above features and advantages, and other features and advantages, of the presently disclosed system and method are readily apparent from the detailed description, including the claims, and examples when taken in connection with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present disclosure will become more fully understood from the detailed description and the accompanying drawings.

[0026] FIG. 1 is a schematic side view illustrating a flexible grinder device, where the flexible grinder device includes a flexible pressure vessel, in accordance with the present disclosure.

[0027] FIG. 2 is a partial cross section view illustrating a portion of the flexible pressure vessel shown in FIG. 1, wherein the flexible pressure vessel has an abrasive layer coupled to an outer surface of the flexible pressure vessel, in accordance with the present disclosure.

[0028] FIG. 3 is a schematic view illustrating the flexible grinder device shown in FIG. 1 inserted into a lightening hole, wherein the flexible pressure vessel is in a pressurized state, in accordance with the present disclosure.

[0029] FIG. 4 is a flowchart illustrating a method for cleaning an as-cast inner hole surface using the flexible grinder device shown in FIGS. 1 through 3, in accordance with the present disclosure.DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, summary, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0031] Reference will now be made in detail to several examples of the disclosure that are illustrated in accompanying drawings. Whenever possible, the same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0032] Rough as-cast surfaces of castings compromise their fatigue durability substantially. Cored lightening hole surfaces have conventionally remained in service as-cast because of difficulty of accessibility by available cleaning or machining tools (e.g., brushes, water jets, turning, etc.), in the case of cast crankshafts made of a cast steel or nodular iron. Thus, inner hole surfaces have become susceptible locations to a premature fatigue failure.

[0033] A flexible grinder device and method is disclosed herein and is designed to provide an efficient and reliable solution for cleaning and grinding inner surfaces of lightening holes and other spaces in metal parts, for example cast ferrous alloy crankshafts (e.g., a nodular iron crankshaft). The flexible grinder device has flexibility that allows conformation with varying geometries of the inner surface of lightening holes, ensuring thorough cleaning and consistent surface finishes. This adaptability reduces the risk of surface defects and stress concentrations, thereby enhancing the fatigue durability of the crankshaft. The flexible grinder device and method disclosed herein remove rough asperities, scales, and possible inclusions on the as-cast inner surfaces. The flexible grinder device and method are also capable of grinding off degenerated graphite skin as needed so that a uniform casting property can be maintained in the casting from surface to matrix, therefore improving the casting’s fatigue endurance and robustness.

[0034] FIG. 1 illustrates a flexible grinder device 10. The flexible grinder device 10 includes a hydraulic motor 12, a control module 14 in communication with the hydraulic motor 12, a flexible pressure vessel 16 coupled to the hydraulic motor 12, and an abrasive layer 18 coupled to the flexible pressure vessel 16. The flexible grinder device 10, and more specifically the flexible pressure vessel 16, may be ushered into an otherwise inaccessible space, for example a lightening hole, and rotated to clean an inner surface of the lightening hole and remove surface imperfections, for example scales, asperites, inclusions, and / or degenerated graphite skin.

[0035] As illustrated in FIG. 1, the flexible grinder device 10 includes a hydraulic motor 12 that is powered by a fluid, for example air (e.g., a pneumatic motor) or water (e.g., a hydraulic water motor). The air or water is compressed and / or pressurized and fed into the hydraulic motor 12 via an inlet 20. The hydraulic motor 12 includes a mechanical actuator that converts hydraulic pressure and flow from the fluid into torque and angular displacement (rotation). The hydraulic motor 12 may include sensors or gauges to monitor a fluid pressure in the flexible pressure vessel 16.

[0036] A control module 14 is in communication with and controls the hydraulic motor 12. The control module 14 regulates operation of the hydraulic motor 12 to ensure precise and consistent performance. The control module 14 may include sensors and / or feedback mechanisms to monitor the operation of the hydraulic motor 12 and adjust speed and / or performance of the hydraulic motor 12 as needed.

[0037] The flexible pressure vessel 16 is mechanically and fluidly coupled to the hydraulic motor 12 and is designed to contain the pressurized fluid 22 (e.g., air, water). The flexible pressure vessel 16 is capable of rotating under the power of the hydraulic motor 12 and is designed to conform to the irregular shapes and sizes of the as-cast inner hole surfaces (e.g., of lightening holes in crankshafts or other cast parts). This flexibility allows the flexible pressure vessel 16, when ushered into a lightening hole, for example, to adapt to varying geometries of the lightening holes, ensuring thorough cleaning and consistent surface finishes. The flexible pressure vessel 16 may be constructed from materials that provide the necessary flexibility and durability, such as reinforced elastomers or composite materials (e.g., an air-tight fabric, a carbon-fiber based composite, rubber, a polymer-based material, a polymer film, and the like). The flexible pressure vessel 16 itself may function as an abrasive without an additional polishing medium attached. In one example, the flexible pressure vessel 16 is formed from an air-tight fabric having a thickness between 0.3 and 1.5 millimeters (mm) in thickness. One of skill in the art would understand the meaning of the term “about.” Alternatively, the term “about” means plus or minus 0.05 mm. In another example, the flexible pressure vessel 16 is hose or tube-shaped. In yet another example, the flexible pressure vessel 16 is configured to withstand a pressure between 10 and 50 pounds per square inch (psi) and have a limited leak rate. The flexible pressure vessel 16 may be rotatable between 500 and 2000 rotations per minute (rpm). Additionally, a length of the flexible pressure vessel 16 may be selective or variable so that a single cast part or multiple cast parts may be simultaneously cleaned.

[0038] As illustrated in FIG. 2, an abrasive layer 18 is coupled to an outer surface of the flexible pressure vessel 16. FIG. 2 illustrates a portion of the flexible pressure vessel as shown in FIG. 1. The abrasive layer 18 functions to grind and clean an inner surface of the lightening holes, removing surface defects and ensuring a smooth and consistent surface finish. The abrasive layer 18 may be composed of materials such as aluminum oxide (Al2O3), diamond grit, silicon carbide (SiC), or other suitable abrasives that provide effective material removal and long-lasting performance. The abrasive layer 18 may be bonded to the flexible pressure vessel 16 using an adhesive binder, for example a glue or a resin. The abrasive layer 18 may include abrasive particles or grains distributed over the adhesive binder and the flexible pressure vessel 16 to form the abrasive layer 18. In one example, the abrasive layer may be between 0.1 and 0.3 millimeters (mm) in thickness. In one example, the abrasive layer may include abrasive particles with an average mesh screen size between 200 and 3000.

[0039] In some instances, the flexible grinder device 10 may include a sealant layer 26 disposed on the flexible pressure vessel. The sealant layer 26 is configured to make the flexible pressure vessel 16 air-tight and / or water-tight. In an example, the sealant layer 26 may include a polyurethane-based fabric sealant, which can provide flexibility, durability, and resistance to water and chemicals. It will be appreciated that the sealant layer 26 may include a variety of other suitable sealants.

[0040] As illustrated in FIG. 3, the flexible grinder device 10 may be ushered into a lightening hole 28 or other irregularly shaped space to clean and provide a finish to the corresponding cast part. In FIG. 3, the flexible pressure vessel 16 is shown as being ushered into the lightening hole 28 of, for example, a journal section 30 of an engine crankshaft. The flexible pressure vessel 16 is configured to receive pressurized fluid (e.g., air, water, and the like) and apply a normal force against and rigidly contact the inner surface 32 of the as-cast surface of the journal section 30. The flexible pressure vessel 16 is then configured to be rotated by the hydraulic motor 12 and function as a grinder. The abrasive layer 18, disposed on an outside surface of the flexible pressure vessel 16 cleans, removes, and / or grinds the inner surface 32.

[0041] In operation, the flexible grinder device 10 is inserted into the lightening hole 28 of a crankshaft or a space in another cast part (e.g., journal section 30). The hydraulic motor 12 is activated causing the flexible pressure vessel 16 to rotate. Pressurized fluid 22 within the flexible pressure vessel 16 allows the flexible pressure vessel 16 to expand and conform to the inner surface 32 of the lightening hole 28. As the flexible pressure vessel 16 rotates, the abrasive layer 18 grinds and cleans the inner surface 32, removing any surface defects and ensuring a smooth and consistent finish. The control module 14 monitors the operation of the hydraulic motor 12 and adjusts performance as needed to ensure optimal cleaning and grinding of the inner surface 32.

[0042] With reference to FIG. 4, a method 100 for cleaning an as-cast inner hole surface using the flexible grinder device 10 shown in FIGS. 1 through 3 is presented, in accordance with the present disclosure. The method 100 starts at step 102.

[0043] Step 102 depicts ushering the flexible pressure vessel 16 of the flexible grinder device 10 into an as-cast inner hole (e.g., lightening hole 28). Ushering the flexible pressure vessel 16 may include using a robot, for example, to usher the flexible pressure vessel 16 when the flexible pressure vessel 16 has little and / or no fluid or pressure. In this way, the flexible pressure vessel 16 can be flexible and / or pliable and be configured to conform to a geography of the inner surface 32 of the as-cast inner hole (e.g., lightening hole 28).

[0044] Step 104 depicts pressurizing the flexible pressure vessel 16 with the fluid 22 so that the flexible pressure vessel 16 flexibly conforms to the as-cast inner hole surface (e.g., inner surface 32). Pressurizing the flexible pressure vessel 16 may include using the hydraulic motor 12 to supply the fluid 22. For example, the hydraulic motor 12 may include a pneumatic motor that provides a supply of pressurized air to the flexible pressure vessel 16, where the flexible pressure vessel 16 becomes rigid or semi-rigid and conforms to the as-cast inner hole surface (e.g., inner surface 32). It is contemplated that pressurizing the flexible pressure vessel 16 may also include using, for example, using a hydraulic motor 12 that uses water or another liquid.

[0045] Step 106 depicts rotating the flexible pressure vessel 16 using the hydraulic motor 12. The hydraulic motor 12 may be used to rotate the flexible pressure vessel 16 when pressurized with fluid to clean, remove, and / or grind the inner surface 32. The control module 14 may be used to cause the hydraulic motor 12 to rotate, and the control module 14 may be used to determine a rate or duration of rotation of the flexible pressure vessel 16.

[0046] Step 108 depicts shot peening the as-cast inner hole surface (e.g., inner surface 32). Shot peening may include bombarding the inner surface 32 with small spherical media, for example steel, to enhance mechanical properties of the inner surface 32. Each particle of spherical media acts similar to a tiny hammer and creates small indentations and a compressive residual stress layer on the inner surface 32, which prevents microcracks forming or spreading on the inner surface 32. The shot peening may be performed using a compressed air or a wheel turbine.

[0047] The flexible grinder device 10 and method 100 of the present disclosure is advantageous and beneficial over the prior art. A need for a more efficient, flexible, and reliable tool for cleaning and grinding the inner surfaces of lightening holes in cast ferrous alloy crankshafts has led to the development of the flexible grinder device 10. The flexible grinder device 10 aims to address the limitations of current methods by providing a tool that can adapt to the varying geometries of lightening holes or other tight or uneven spaces ensuring thorough cleaning and consistent surface finishes while reducing the risk of damage to the crankshaft or other cast part. The combination of the flexible pressure vessel 16 and the abrasive layer 18 provides an efficient and reliable solution for finishing the inner surfaces 32 of lightening holes and other irregular or hard-to-reach spaces in as-cast parts (e.g., ferrous alloy crankshafts). The adaptability of the flexible pressure vessel 16 reduces the risk of surface defects and stress concentrations, thereby enhancing the fatigue durability of the crankshaft / cast part.

[0048] This description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims.

Examples

Embodiment Construction

[0030]The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, summary, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0031]Reference will now be made in detail to several examples of the disclosure that are illustrated in accompanying drawings. Whenever possible, the same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0032]Rough as-cast surfaces of castings compromise their fatigue durability sub...

Claims

1. A flexible grinder device, comprising:a hydraulic motor powered by a fluid;a control module in communication with the hydraulic motor;a flexible pressure vessel coupled to the hydraulic motor, wherein the flexible pressure vessel is configured to contain the fluid, wherein the fluid is configured to be pressurized, wherein the flexible pressure vessel is rotatable by the hydraulic motor, and wherein the flexible pressure vessel is conformable with an as-cast inner hole surface; andan abrasive layer coupled to an outer surface of the flexible pressure vessel.

2. The flexible grinder device of claim 1, wherein the fluid includes at least one of air or water.

3. The flexible grinder device of claim 1, wherein the flexible pressure vessel is formed from at least one of a carbon-fiber based composite, rubber, or a polymer-based material.

4. The flexible grinder device of claim 1, wherein the flexible pressure vessel is formed from an air-tight fabric.

5. The flexible grinder device of claim 1, wherein the flexible pressure vessel is tube-shaped.

6. The flexible grinder device of claim 1, wherein the flexible pressure vessel is configured to withstand a pressure between 10 and 50 pounds per square inch (psi).

7. The flexible grinder device of claim 1, wherein the flexible pressure vessel is between 0.3 and 1.5 millimeters (mm) in thickness.

8. The flexible grinder device of claim 1, wherein the flexible pressure vessel is rotatable between 500 and 2000 rotations per minute (rpm).

9. The flexible grinder device of claim 1, wherein the abrasive layer is between 0.1 and 0.3 millimeters (mm) in thickness.

10. The flexible grinder device of claim 1, wherein the abrasive layer includes abrasive particles formed from at least one of aluminum oxide (Al2O3) or silicon carbide (SiC).

11. The flexible grinder device of claim 1, wherein the abrasive layer includes abrasive particles with an average mesh screen size between 200 and 3000.

12. The flexible grinder device of claim 1, further comprising:a sealant layer disposed on the flexible pressure vessel and configured to make the flexible pressure vessel at least one of air-tight or water-tight.

13. A flexible grinder device, comprising:a hydraulic motor powered by a fluid including at least one of air or water;a control module in communication with the hydraulic motor;a flexible pressure vessel coupled to the hydraulic motor, wherein the flexible pressure vessel is configured to contain the fluid, wherein the fluid is configured to be pressurized, wherein the flexible pressure vessel is rotatable by the hydraulic motor, wherein the flexible pressure vessel is conformable with an as-cast inner hole surface, and wherein the flexible pressure vessel is configured to withstand a pressure between 10 and 50 pounds per square inch (psi); andan abrasive layer coupled to an outer surface of the flexible pressure vessel, wherein the abrasive layer includes abrasive particles formed from at least one of aluminum oxide (Al2O3) or silicon carbide (SiC).

14. The flexible grinder device of claim 13, wherein the flexible pressure vessel is formed from at least one of a carbon-fiber based composite, rubber, or a polymer-based material.

15. The flexible grinder device of claim 13, wherein the flexible pressure vessel is between 0.3 and 1.5 millimeters (mm) in thickness.

16. The flexible grinder device of claim 13, wherein the flexible pressure vessel is rotatable between 500 and 2000 rotations per minute (rpm).

17. The flexible grinder device of claim 13, wherein the abrasive layer is between 0.1 and 0.3 millimeters (mm) in thickness.

18. The flexible grinder device of claim 13, wherein the abrasive layer includes abrasive particles with an average mesh screen size between 200 and 3000.

19. A method for cleaning an as-cast inner hole surface using a flexible grinder device, comprising:ushering a flexible pressure vessel of the flexible grinder device into an as-cast inner hole, wherein the flexible pressure vessel is mechanically and fluidly coupled to a hydraulic motor powered by a fluid;pressurizing the flexible pressure vessel with the fluid so that the flexible pressure vessel flexibly conforms to the as-cast inner hole surface; androtating the flexible pressure vessel using the hydraulic motor, wherein an abrasive layer disposed on an outer surface of the flexible pressure vessel cleans the as-cast inner hole surface as the flexible pressure vessel rotates.

20. The method of claim 19, further comprising:shot peening the as-cast inner hole surface.

Images