A keyway type double-sleeve oil passage cylinder seat

Abstract

This invention provides a keyway-type double-stage hydraulic passage cylinder seat, belonging to the field of aircraft landing gear design technology. The first and second hydraulic circuits of the cylinder seat differ in height by a predetermined distance; both hydraulic circuits are normal brake circuits; the cylinder seat is fixed to the external brake device housing; the landing gear lever arm is installed in the keyway at the bottom of the cylinder seat, and the hydraulic circuits of both circuits are located within the ribs. Compared to a cylinder seat structure design with one normal brake circuit and one stress brake circuit, the two hydraulic circuits provided by this invention place higher demands on the structure. This invention adopts a method where the two circuits do not intersect in height, minimizing structural weight while ensuring performance.

Description

Technical Field

[0001] This invention belongs to the field of aircraft landing gear design technology, and particularly relates to a keyway-type double-set oil passage cylinder seat. Background Technology

[0002] The wheel assembly and braking system are mounted together on the aircraft's main landing gear. The braking system mainly consists of a brake disc assembly, a brake housing assembly, and a cylinder block assembly. When the aircraft brakes, high-pressure brake fluid enters the piston chamber through the oil passage in the cylinder block. Under the braking pressure, the piston moves forward, pressing the stationary brake disc assembly against the rotating brake disc assembly. The cylinder block is mainly used to receive the brake fluid pressure to provide thrust and transmit braking torque, and it is also used to mount piston components.

[0003] In related technologies, the two sets of oil passages in the cylinder block are on the same plane, resulting in a relatively heavy cylinder block. However, in some scenarios, a cylinder block with two sets of oil passages that are lighter is required, so existing cylinder blocks cannot meet the requirements. Summary of the Invention

[0004] To address the problem that existing cylinder blocks are too heavy for applications requiring two lightweight cylinder blocks with two sets of hydraulic lines, this invention proposes a keyway-type double-set hydraulic passage cylinder block, the technical solution of which is as follows:

[0005] A keyway-type double-stage hydraulic passage cylinder seat is provided, comprising: a first hydraulic circuit, a second hydraulic circuit, a keyway, and ribs.

[0006] The first set of hydraulic circuits and the second set of hydraulic circuits are at a preset height difference; both sets of hydraulic circuits are normal brake circuits; the cylinder seat is fixed on the external brake device housing; the landing gear lever arm is installed in the keyway at the bottom of the cylinder seat; and the oil passages of the two sets of hydraulic circuits are located inside the ribs.

[0007] When the aircraft brakes, the high-pressure brake fluid enters the piston bore through one of the hydraulic circuits in the cylinder block. The piston, installed in the piston bore, moves forward under the braking pressure, pressing the stationary brake disc assembly against the rotating brake disc assembly, thereby generating a frictional torque that stops the rotating wheels. The landing gear lever arm is installed in the keyway of the cylinder block, thereby transmitting this frictional torque to the landing gear shaft. When one hydraulic circuit fails, the other hydraulic circuit operates.

[0008] Optionally, the first hydraulic circuit includes three piston holes: a first hydraulic circuit piston hole, an intermediate hydraulic circuit piston hole, and a last hydraulic circuit piston hole. The first hydraulic circuit piston hole and the intermediate hydraulic circuit piston hole, as well as the intermediate hydraulic circuit piston hole and the last hydraulic circuit piston hole, are connected by the first hydraulic circuit. The inlet of the first hydraulic circuit is located at the entrance of the first hydraulic circuit piston hole and is connected to the system pipeline. It is used to transport system hydraulic oil through the first hydraulic circuit piston hole into the first hydraulic circuit and finally into the last hydraulic circuit piston hole.

[0009] The second hydraulic circuit includes three piston holes: a first piston hole, a middle piston hole, and a last piston hole. The first and middle piston holes, and the middle and last piston holes, are connected by the second hydraulic circuit. The inlet of the second hydraulic circuit is located at the first piston hole and is connected to the system pipeline. This inlet is used to transport system hydraulic oil through the first piston hole to the second hydraulic circuit and ultimately to the last piston hole.

[0010] The first and second sets of oil circuits are located within the ribs.

[0011] Optionally, the keyway-type double-sleeve oil passage cylinder seat also includes multiple bolt holes located in the middle of the cylinder seat. The multiple bolt holes are distributed around the circumference and are used to install bolts to fix the cylinder seat to the external brake device housing.

[0012] Optionally, the keyway-type double-set oil passage cylinder seat also includes an indicator rod hole. The indicator rod hole is located near the piston hole of the first set of hydraulic oil circuits in the middle, and the distance between the indicator rod hole and the piston hole of the first set of hydraulic oil circuits in the middle is a preset distance. The indicator rod hole is used to install an indicator rod, and the remaining thickness of the brake disc after wear can be detected through the indicator rod.

[0013] Optionally, the first hydraulic circuit and the second hydraulic circuit differ in height by 5 mm.

[0014] Optionally, the cylinder block structure is a high-strength aluminum alloy forging.

[0015] Optionally, the diameter of the first set of oil circuits is 5 mm, and the length of the first set of oil circuits between the first set of hydraulic oil circuit piston hole and the middle set of hydraulic oil circuit piston hole is 165 mm.

[0016] The diameter of the second set of oil circuits is 5 mm, and the length of the second set of oil circuits between the piston hole of the first set of hydraulic oil circuits and the piston hole of the middle set of hydraulic oil circuits is 145 mm.

[0017] Optionally, the piston holes of the first set of hydraulic circuits and the second set of hydraulic circuits are circular blind holes with a diameter of 46 mm and a depth of 26 mm.

[0018] Optionally, the inlet ports of the first and second hydraulic circuits are circular, with a chamfer of 1×45°.

[0019] Optionally, each bolt hole is a circular through hole with a diameter of 18 mm and a chamfer of 2×45° at the opening.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The cylinder block structure proposed in this invention has two sets of hydraulic oil circuits, both of which are normal brake oil circuits. Compared with the cylinder block structure design of one normal brake oil circuit and one stress brake oil circuit, it puts forward higher requirements in terms of structure. This invention adopts the method of two sets of oil circuits not intersecting in height, which minimizes the structural weight while ensuring performance.

[0022] 2. The symmetrical design along the centerline of the cylinder block proposed in this invention allows for quick installation of the braking device on the left or right side of the main landing gear, providing better installation convenience and maintainability. Furthermore, it includes indicator rod holes to secure the indicator rod and serve as a reference for judging the wear condition of the brake disc.

[0023] 3. The cylinder block proposed in this invention uses ribs to connect the piston bore, thereby ensuring the strength of the part and minimizing its weight. Calculations show that under twice the maximum braking static pressure of 42 MPa, the maximum MISES stress of the cylinder block is 349 MPa. The weight of the structure of this invention is 3.94 kg, representing a weight reduction of over 8% compared to similar structures.

[0024] 4. The cylinder block proposed in this invention is made of high-strength aluminum alloy forgings, which has strong resistance to stress corrosion, good tensile strength, fracture toughness and temperature adaptability, and is conducive to product weight reduction design.

[0025] 5. The cylinder block proposed in this invention employs many detailed design features to prevent failure caused by stress concentration. For example, the bolt connection holes are chamfered, all oil passage holes have chamfered or rounded openings, and the fuse hole is located in a low-stress area of ​​the cylinder block. These measures all help reduce stress concentration and improve the lifespan of the cylinder block. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view of the first hydraulic circuit of the keyway-type double-stage oil passage cylinder seat provided by the present invention.

[0027] Figure 2 This is a cross-sectional view of the second hydraulic circuit of the keyway-type double-stage oil passage cylinder seat provided by the present invention;

[0028] Figure 3 This is a longitudinal sectional view of the keyway-type double-set oil passage cylinder seat structure provided by the present invention;

[0029] Figure 4 This is a stress cloud diagram of the keyway-type double-set oil passage cylinder seat structure provided by the present invention.

[0030] In the diagram: 1-Piston hole of the first set of hydraulic circuits; 2-First set of hydraulic circuits; 3-Inlet of the first set of hydraulic circuits; 4-Bolt hole; 5-Keyway; 6-Indicator rod hole; 7-Piston hole of the second set of hydraulic circuits; 8-Second set of hydraulic circuits; 9-Inlet of the second set of hydraulic circuits; 10-Rib. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0032] To meet the requirements of dual-redundancy control and maximize weight reduction while ensuring performance, this invention proposes a keyway-type double-layer oil passage cylinder seat. The oil passage is not closed, which is beneficial for vibration reduction. This invention improves the structure's resistance to oil pressure pulses and reduces structural weight.

[0033] This invention proposes a keyway-type double-stage hydraulic passage cylinder seat, the cylinder seat structure being a high-strength aluminum alloy forging. This keyway-type double-stage hydraulic passage cylinder seat includes: two sets of hydraulic circuits (including a first set and a second set of hydraulic circuits), a keyway, and ribs. The first set of hydraulic circuits and the second set of hydraulic circuits differ in height by 5 mm. Both sets of hydraulic circuits are normal brake circuits. The cylinder seat is fixed to the external brake device housing; the landing gear lever arm is installed in the keyway of the cylinder seat, and the hydraulic circuits of both sets are located within the ribs.

[0034] When the aircraft brakes, the high-pressure brake fluid of the system enters the piston hole through one of the hydraulic lines in the cylinder seat. The piston installed in the piston hole moves forward under the action of braking pressure, pressing the stationary brake disc assembly against the rotating brake disc assembly, thereby generating a frictional torque that stops the rotating wheels. The landing gear lever arm is installed in the keyway 5 of the cylinder seat, thereby transmitting this frictional torque to the landing shaft.

[0035] When one hydraulic circuit fails, the other hydraulic circuit will operate.

[0036] Specifically, such as Figure 1 , Figure 2 and Figure 3As shown, the first hydraulic circuit includes a piston hole 1, a circuit 2, and an inlet 3; the second hydraulic circuit includes a piston hole 7, a circuit 8, and an inlet 9.

[0037] To facilitate processing, the piston hole 1 of the first set of hydraulic oil circuits is a circular blind hole with a diameter of 46 mm and a depth of 26 mm.

[0038] In this invention, the number Ms of the first hydraulic circuit piston hole 1 can be determined according to the following formula:

[0039] Ms = μ d F n (P-ΔP)n T R m Fn=mπr 2

[0040] Where: μ d F is the coefficient of kinetic friction. n The total area of ​​all pistons, in cm² 2 P is the applied braking pressure, in MPa; ΔP is the pressure loss of the piston assembly, in MPa; n T For friction surfaces, the number is even; R m is the median diameter of the friction surface, in cm; m is the number of pistons; r is the piston radius.

[0041] For example, the first set of hydraulic circuits may include three piston holes 1: the first piston hole 1, the middle piston hole 1, and the last piston hole 1. Figure 1 As shown, the first set of hydraulic oil circuit piston holes 1 and the middle set of hydraulic oil circuit piston holes 1, and the middle set of hydraulic oil circuit piston holes 1 and the end set of hydraulic oil circuit piston holes 1 are connected by the first set of oil circuits 2, thereby ensuring that the hydraulic oil is evenly distributed between each set of hydraulic oil circuit piston holes 1.

[0042] The diameter of the first set of oil circuits 2 is 5 mm, and the length of the first set of oil circuits 2 between the first set of hydraulic oil circuit piston hole 1 and the middle set of hydraulic oil circuit piston hole 1 is 165 mm.

[0043] The first hydraulic oil inlet 3 is located at the entrance of the first hydraulic oil circuit piston hole 1. The first hydraulic oil inlet 3 is circular, and the chamfer of the opening of the first hydraulic oil inlet 3 is 1×45°. The first hydraulic oil inlet 3 is connected to the system pipeline and is used to transport the system hydraulic oil through the first hydraulic oil circuit piston hole 1 to the first oil circuit 2 and finally to the last hydraulic oil circuit piston hole 1.

[0044] In another embodiment, the keyway-type double-sleeve oil passage cylinder seat may further include bolt holes 4. Bolt holes 4 are located in the middle of the cylinder seat. For example, as... Figure 1 As shown, the cylinder block can be provided with 6 bolt holes 4 in the middle. The 6 bolt holes 4 are distributed around the circumference. Each bolt hole 4 is a circular through hole with a diameter of 18 mm and a chamfer of 2×45° at the opening. The bolt holes 4 are used to install bolts and fix the cylinder block to the external brake device housing.

[0045] like Figure 1 As shown, the bottom of the cylinder block is provided with a keyway 5, which cooperates with the landing gear lever arm to connect the cylinder block to the landing gear and transmit the friction torque of the brake disc; the length × width × height of the keyway 5 is 51 mm × 63 mm × 24 mm.

[0046] In another embodiment, the keyway-type double-sleeve hydraulic passage cylinder seat may further include an indicator rod hole 6. The indicator rod hole 6 is located near the piston hole 1 of the intermediate first hydraulic circuit, and the distance between it and the piston hole 1 is a preset distance, typically 59.7 mm. The indicator rod hole 6 is a circular through hole with a diameter of 4 mm. The indicator rod hole 6 is used to install an indicator rod, which allows detection of the remaining thickness of the brake disc after wear.

[0047] For ease of processing, the piston hole 7 of the second hydraulic circuit is a circular blind hole with a diameter of 46 mm and a depth of 26 mm.

[0048] like Figure 2 As shown, the second hydraulic circuit may include three piston holes 7: a first piston hole 7, a middle piston hole 7, and a last piston hole 7. The first and middle piston holes 7, and the middle and last piston holes 7, are connected by a second hydraulic circuit 8, thereby ensuring that the hydraulic oil is evenly distributed among the piston holes.

[0049] The diameter of the second set of oil circuits 8 is 5 mm, and the length of the second set of oil circuits 8 between the first set of hydraulic oil circuit piston hole 7 and the middle set of hydraulic oil circuit piston hole 7 is 145 mm.

[0050] The second hydraulic oil inlet 9 is located at the piston hole 7 of the first hydraulic oil circuit. The second hydraulic oil inlet 9 is circular and has a chamfer of 1×45°. The second hydraulic oil inlet 9 is connected to the system pipeline and is used to transport the system hydraulic oil through the piston hole 7 of the first hydraulic oil circuit to the second oil circuit 8 and finally to the piston hole 7 of the last hydraulic oil circuit.

[0051] The first set of oil circuits 2 and the second set of oil circuits 8 are located inside the rib 10, and mainly bear the hydraulic pulses and structural stress from the oil from the first set of oil circuits 2 and the second set of oil circuits 8.

[0052] When the system supplies oil to the first set of hydraulic circuits, the hydraulic oil enters the first set of hydraulic circuits 2 through the oil inlet 3 of the first set of hydraulic circuits. The hydraulic oil fills the three piston holes 1 of the first set of hydraulic circuits. The high-pressure hydraulic oil pushes the piston in the piston hole 1 of the first set of hydraulic circuits out, thereby pressing the rotating brake disc and generating the frictional torque of braking the aircraft wheels.

[0053] When the system supplies oil to the second hydraulic circuit, the hydraulic oil enters the second hydraulic circuit 8 through the oil inlet 9. The hydraulic oil fills the three piston holes 7 of the second hydraulic circuit. The high-pressure hydraulic oil pushes the piston in the piston hole 7 of the second hydraulic circuit out, thereby pressing the rotating brake disc and generating the frictional torque to brake the aircraft wheels.

[0054] To verify whether the structure of this invention meets the usage requirements, stress simulation calculations were also performed, such as... Figure 4 As shown, it can be obtained that under twice the maximum braking static pressure of 42MPa, the maximum MISES stress S of the cylinder seat is 349MPa.

[0055] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A keyway-type double-sleeve oil passage cylinder seat, characterized in that, include: The first set of hydraulic circuits, the second set of hydraulic circuits, keyways, and ribs. The first set of hydraulic circuits and the second set of hydraulic circuits are at a preset height difference; both sets of hydraulic circuits are normal brake circuits; the cylinder seat is fixed on the external brake device housing; the landing gear lever arm is installed in the keyway at the bottom of the cylinder seat; and the oil passages of the two sets of hydraulic circuits are located inside the ribs. When the aircraft brakes, the high-pressure brake fluid enters the piston bore through one of the hydraulic lines in the cylinder block. The piston, installed in the piston bore, moves forward under the braking pressure, pressing the stationary brake disc assembly against the rotating brake disc assembly, thereby generating a frictional torque that stops the rotating wheels. The landing gear lever arm is installed in the keyway of the cylinder block, thereby transmitting this frictional torque to the landing gear shaft. When one hydraulic line fails, the other hydraulic line operates. The number of piston holes in the first set of hydraulic circuits Ms = Fn=mπr 2 , In the formula, The coefficient of kinetic friction; P represents the total area of ​​all pistons; P is the applied braking pressure; ΔP is the pressure loss of the piston assembly. For friction surfaces, the number is even; denoted as the mid-diameter of the friction surface; m is the number of pistons; and r is the piston radius.

2. The keyway-type double-sleeve oil passage cylinder seat according to claim 1, characterized in that, The first set of hydraulic circuits includes three piston holes: the first set of hydraulic circuit piston hole, the middle set of hydraulic circuit piston hole, and the last set of hydraulic circuit piston hole. The piston hole of the first hydraulic circuit and the piston hole of the intermediate hydraulic circuit are connected by the first hydraulic circuit. The piston hole of the intermediate hydraulic circuit and the piston hole of the last hydraulic circuit are connected by the first hydraulic circuit. The oil inlet of the first hydraulic circuit is located at the entrance of the piston hole of the first hydraulic circuit. The oil inlet of the first hydraulic circuit is connected to the system pipeline and is used to transport the system hydraulic oil through the piston hole of the first hydraulic circuit to the first hydraulic circuit and finally to the piston hole of the last hydraulic circuit. The second hydraulic circuit includes three piston holes: the first piston hole, the middle piston hole, and the last piston hole. The piston holes of the first and second hydraulic circuits and the piston holes of the middle and second hydraulic circuits, as well as the piston holes of the middle and second hydraulic circuits and the piston holes of the last and second hydraulic circuits, are connected by the second hydraulic circuit. The inlet of the second hydraulic circuit is located at the piston hole of the first and second hydraulic circuits. The inlet of the second hydraulic circuit is connected to the system pipeline and is used to transport the system hydraulic oil through the piston holes of the first and second hydraulic circuits to the second hydraulic circuit and finally to the piston hole of the last and second hydraulic circuits. The first and second sets of oil circuits are located within the ribs.

3. The keyway-type double-sleeve oil passage cylinder seat according to claim 1, characterized in that, The keyway-type double-layer oil passage cylinder seat also includes multiple bolt holes located in the middle of the cylinder seat. These bolt holes are distributed circumferentially and are used to install bolts, thus fixing the cylinder seat to the external brake device housing.

4. The keyway-type double-sleeve oil passage cylinder seat according to claim 1, characterized in that, The keyway-type double-set oil passage cylinder seat also includes an indicator rod hole. The indicator rod hole is located near the piston hole of the first set of hydraulic oil circuits in the middle, and the distance between the indicator rod hole and the piston hole of the first set of hydraulic oil circuits in the middle is a preset distance. The indicator rod hole is used to install an indicator rod, and the remaining thickness of the brake disc after wear can be detected through the indicator rod.

5. The keyway-type double-sleeve oil passage cylinder seat according to claim 1, characterized in that, The first hydraulic circuit and the second hydraulic circuit differ in height by 5 millimeters.

6. The keyway-type double-sleeve oil passage cylinder seat according to claim 1, characterized in that, The cylinder block structure is made of high-strength aluminum alloy forgings.

7. The keyway-type double-sleeve oil passage cylinder seat according to claim 2, characterized in that, The diameter of the first set of oil circuits is 5 mm, and the length of the first set of oil circuits between the piston hole of the first set of hydraulic oil circuits and the piston hole of the middle set of hydraulic oil circuits is 165 mm. The diameter of the second set of oil circuits is 5 mm, and the length of the second set of oil circuits between the piston hole of the first set of hydraulic oil circuits and the piston hole of the middle set of hydraulic oil circuits is 145 mm.

8. The keyway-type double-sleeve oil passage cylinder seat according to claim 2, characterized in that, The piston holes of the first and second hydraulic circuits are circular blind holes with a diameter of 46 mm and a depth of 26 mm.

9. The keyway-type double-sleeve oil passage cylinder seat according to claim 2, characterized in that, The inlets of the first and second hydraulic circuits are circular, with a chamfer of 1×45°.

10. The keyway-type double-sleeve oil passage cylinder seat according to claim 3, characterized in that, Each bolt hole is a circular through hole with a diameter of 18 mm and a chamfer of 2×45° at the opening.

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