A grinding fixture and method for cam locator pins of an aeroengine

Abstract

The application relates to a grinding clamping device and method for a cam positioning pin of an aero-engine, and solves the problem that the cam positioning pin of the aero-engine cannot be clamped for grinding.(1) A positioning bushing is designed to clamp and position the positioning pin, and the cylindrical surface of the positioning pin is ensured to be completely extended to facilitate grinding operation; the overall design is a cylindrical body with a hole, and the cross section is designed as four sections, from left to right, which are an M12 thread section, a wide ring groove section, a thin ring groove section and a thin wall section;(2) a positioning rod is designed to cooperate with the positioning bushing, the positioning pin is ensured to be pressed, and the positioning pin is prevented from shaking in the positioning bushing; the overall structure is a cylindrical body, and from left to right, the structure is a pressing contact section, a thread section and a tightening clamping section. The grinding of the cam positioning pin of the main fuel pump regulator of the type can be realized by using the device and the method. The device and the method are used, the problem that the positioning pin cannot be clamped for grinding when the size of the positioning pin is large is effectively solved, and the spare part procurement pressure is greatly relieved.

Description

Technical Field

[0001] This invention relates to the field of aircraft engine component repair, and in particular to a grinding and clamping device and method for aircraft engine cam locating pins. Background Technology

[0002] The main fuel regulator is a core control accessory for aero engines. It is primarily used to reliably control the engine under varying flight altitudes, speeds, atmospheric temperatures, and pressures, ensuring stable engine operation under all conditions. As a highly precise mechanical-hydraulic control accessory, the main fuel regulator has a complex internal structure, requiring extremely high precision in the coordination and cooperation between its components, and demanding strict dimensional control during maintenance.

[0003] like Figure 1 As shown, the cam assembly consists of cam 01, locating pin 02, and camshaft 03. During aero-engine repair, locating pin 02 is required according to process requirements to ensure proper fit with the hole. Due to manufacturing tolerances, some locating pins have an excessively large outer diameter. Therefore, the cylindrical surface that mates with the hole needs to be ground to reduce the outer diameter of the locating pin. During grinding, the locating pin needs to be clamped on a grinding head, and the rotation of the grinding head ensures uniform circumferential grinding of the locating pin. Because the locating pin is small, it cannot be directly clamped and positioned using a grinding head. Summary of the Invention

[0004] This invention provides a grinding clamping device and method for aircraft engine cam locating pins, solving the problem of the inability to clamp and grind aircraft engine cam locating pins.

[0005] This invention is achieved through the following technical solutions:

[0006] A grinding and clamping device and method for aero-engine cam locating pins, with specific technical solution as follows:

[0007] (1) Design of positioning bushing: Its function is to clamp and position the positioning pin and ensure that the cylindrical surface of the positioning pin is fully extended for grinding operation. Its typical structural features are that the overall design is a cylinder with holes, and the cross-section is designed as 4 sections, from left to right: M12 thread section, wide annular groove section, fine annular groove section and thin wall section.

[0008] M12 threaded section: used to mate with the threaded section of the positioning rod to ensure the clamping of the end of the positioning pin;

[0009] Wide annular groove: a machining process groove used to ensure the root of the threaded section protrudes and to ensure the feed depth of the positioning rod;

[0010] Fine annular groove section: Its size is determined according to the outer diameter of the end of the locating pin to ensure that the locating pin can be installed to the bottom normally;

[0011] Thin-walled section: Its inner hole size is determined according to the outer circle size of the cylindrical surface of the locating pin. There are roughness requirements on the inner side, and the outer side is designed as a bevel structure. On the one hand, it ensures that the cylindrical surface is sufficiently convex to ensure the grinding effect, and on the other hand, it can avoid the accumulation of grinding paste.

[0012] (2) Design positioning rod: Its function is to cooperate with the positioning bushing to ensure the positioning pin is pressed and to prevent the positioning pin from shaking in the positioning bushing. Its typical structural feature is that the overall structure is cylindrical, and from left to right, it consists of a pressing contact section, a threaded section, and a tightening clamping section.

[0013] The pressing contact section: its left end face directly contacts the end face of the locating pin, and its end face roughness and flatness have high requirements;

[0014] Threaded section: Used to mate with the threaded section of the positioning bushing to ensure the axial movement of the positioning rod;

[0015] Tightening clamping section: It has a groove with a width of 8mm, which serves as the force application point when tightening or loosening.

[0016] The device and method used here can be used to grind the cam locating pin of this type of main fuel pump regulator. The use of this invention and method effectively solves the problem that the locating pin is too large to be clamped for grinding in the past, and greatly alleviates the pressure of spare parts procurement. Attached Figure Description

[0017] Figure 1 Here is a structural diagram of the cam assembly;

[0018] Figure 2 Figure b is a sectional view of the positioning bushing structure, where Figure b is the DD section view of Figure a.

[0019] Figure 3 Figure b is a cross-sectional view of the positioning rod structure, where the figure b is the EE section view of figure a.

[0020] Figure 4 This is a schematic diagram of the grinding clamp. Detailed Implementation

[0021] like Figure 2 , 3 As shown, the grinding and clamping device for the cam locating pin of the aero-engine of the present invention includes a locating bushing and a locating rod, and the specific method is as follows:

[0022] (1) Press Figure 4 As shown, install the positioning pin 1 in the positioning bushing 3, and tighten the positioning rod 4 with an open wrench with S=8mm to ensure that the positioning pin 1 is pressed into the positioning bushing 3.

[0023] (2) Tighten the positioning rod 4 to the clamping section. Figure 4 The Φ10 end shown is clamped on the rotating grinding head;

[0024] (3) Check that the runout of the cylindrical surface of the positioning pin 1 relative to the cylindrical surface of the positioning rod 4 should not exceed 0.05mm. This can be achieved by slightly loosening the positioning rod 4 and adjusting the position of the positioning pin 1.

[0025] (4) Start the grinding head and grind the cylindrical surface of the positioning pin 1 in conjunction with the existing grinding fixture 2. You can measure while grinding to ensure the dimensional requirements are met.

[0026] (5) Remove the positioning rod 4 from the grinding machine and loosen the positioning rod 4 with an open wrench with S=8mm, and remove the positioning pin 1.

Claims

1. A grinding and clamping device for a cam locating pin of an aircraft engine, characterized in that: Includes positioning bushings and positioning rods; The positioning bushing clamps and positions the positioning pin, and ensures that the cylindrical surface of the positioning pin is fully extended for grinding. The overall design is a cylinder with holes, and the cross-section is designed with 4 sections, from left to right: M12 thread section, wide annular groove section, narrow annular groove section and thin-walled section. M12 threaded section: used to mate with the threaded section of the positioning rod to ensure the clamping of the end of the positioning pin; Wide annular groove: a machining process groove used to ensure the root of the threaded section protrudes and to ensure the feed depth of the positioning rod; Fine annular groove section: Its size is determined according to the outer diameter of the end of the locating pin to ensure that the locating pin can be installed to the bottom normally; Thin-walled section: Its inner hole size is determined according to the outer circle size of the cylindrical surface of the locating pin. There are roughness requirements on the inner side, and the outer side is designed as a bevel structure. On the one hand, it ensures that the cylindrical surface is sufficiently convex to ensure the grinding effect, and on the other hand, it can avoid the accumulation of grinding paste. The positioning rod cooperates with the positioning bushing to ensure the positioning pin is pressed and to prevent the positioning pin from shaking in the positioning bushing. The overall structure is cylindrical, and from left to right, it consists of a pressing contact section, a threaded section, and a tightening clamping section. The pressing contact section: its left end face directly contacts the end face of the locating pin, and its end face roughness and flatness are subject to requirements; Threaded section: Used to mate with the threaded section of the positioning bushing to ensure the axial movement of the positioning rod; Tightening clamping section: milled with clamping grooves, serving as the force application point when tightening or loosening.

2. A grinding and clamping method for an aircraft engine cam locating pin, using the clamping device described in claim 1, characterized in that: Specific steps for: 1) Install the locating pin in the locating bushing and tighten the locating rod with an open-end wrench to ensure that the locating pin is pressed into the locating bushing; 2) Tighten the positioning rod and clamp it onto the rotating grinding head; 3) Check that the runout of the cylindrical surface of the locating pin relative to the cylindrical surface of the locating rod does not exceed 0.05mm. This can be achieved by slightly loosening the locating rod and adjusting the position of the locating pin. 4) Start the grinding head and, in conjunction with the existing grinding fixture, grind the cylindrical surface of the locating pin. Measurements can be taken while grinding to ensure dimensional requirements are met. 5) Remove the positioning rod from the grinder and loosen it with an open-end wrench to remove the positioning pin.

Images