Dry type piston structure for aviation airplane wheel brake

Abstract

A dry type piston structure for an aviation airplane wheel brake comprises a pull rod, a lining and a piston, the pull rod comprises an end plate and a rod shaft, the piston is arranged in an inner cavity of the lining in a sliding mode, the end plate of the pull rod and the end face of the lining are installed in a matched mode, a through hole communicated with the inner cavity of the lining is formed in the end plate of the pull rod, and a support is arranged in an inner cavity of the piston. The support is sleeved with a return spring, an expansion pipe is arranged in an inner hole of the support, a horn mouth is formed in the end, away from an end plate of the pull rod, of the expansion pipe, the outer surface of the horn mouth extends out of the inner hole and abuts against the support, and a rod shaft in the middle of the pull rod penetrates through the expansion pipe and extends out of the horn mouth of the expansion pipe. The rod shaft of the pull rod is sleeved with a ball head at the horn mouth of the expansion pipe and provided with a nut through threads, a heat insulation block is arranged at an opening of an inner cavity of the piston, and a first sealing ring and a first protection ring are arranged between the rod shaft of the pull rod and the piston. Brake hydraulic oil is isolated outside the piston, reliability is high, output force is stable, and maintenance is convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft wheel brakes, and in particular to a dry piston structure used for aircraft wheel brakes. Background Art

[0002] The piston is installed in the cylinder seat of the aircraft wheel brake device. Under the action of the brake hydraulic oil, the brake pressure is converted into thrust to press the brake disc to achieve braking. Figure 1 As shown, all parts in the piston are immersed in hydraulic oil for operation. The hydraulic oil enters the inner cavity of the piston and is close to the brake disc. The hydraulic oil is affected by the temperature of the brake disc, which will cause carbonization of the oil and shedding of the piston surface during operation to produce excess matter, affecting the performance of the vehicle. When inspecting the piston, it is necessary to completely disassemble the piston before inspecting and replacing the internal parts of the piston, which is inconvenient to inspect the internal parts of the piston. Therefore, in the design process of the piston, preventive design is required for the materials of each part, surface treatment measures, etc. Otherwise, there may be a risk of excess matter falling off the piston surface during operation. Summary of the Invention

[0003] In order to solve the problems mentioned in the above background technology, the present invention provides a dry piston structure for aircraft wheel brakes.

[0004] The present invention discloses the following technical scheme: a dry piston structure for aircraft wheel brakes, comprising a pull rod, a bushing and a piston, the pull rod comprising an end plate and a rod shaft, the piston being slidably arranged in the inner cavity of the bushing, the end plate of the pull rod being matched with the end face of the bushing, the end plate of the pull rod being provided with a through hole communicating with the inner cavity of the bushing, the inner cavity of the piston being provided with a support, the outer sleeve of the support being provided with a return spring, the two ends of the return spring respectively abutting against the inner end face of the piston cavity and the inner end face of the cone of the support to control the piston to reset, an expansion tube being provided in the inner hole of the support, the end of the expansion tube away from the end plate of the pull rod being provided with a bell mouth, the outer surface of the bell mouth extending out of the inner hole abutting against the support, the rod shaft in the middle of the pull rod penetrating the expansion tube and extending out of the bell mouth of the expansion tube, the rod shaft of the pull rod being provided with a ball head at the bell mouth of the expansion tube and a nut being installed through a thread, an insulation block being provided at the opening of the inner cavity of the piston, and a first sealing ring and a first protective ring being provided between the rod shaft of the pull rod and the piston.

[0005] Furthermore, the piston is provided with an annular groove for mounting the first sealing ring and the first protective ring.

[0006] Furthermore, the first sealing ring and the first protective ring are arranged in parallel.

[0007] Furthermore, multiple sets of second sealing rings and second protective rings are provided between the piston and the bushing.

[0008] Furthermore, the heat insulation block is mounted on the piston via threads.

[0009] Beneficial effects: Compared with the prior art, the dry piston structure of the present invention isolates the brake hydraulic oil from the outside of the piston by setting a through hole connected to the inner cavity of the bushing on the pull rod, and adding a sealing ring and a protective ring between the piston and the pull rod, thereby solving problems such as high oil temperature after aircraft wheel braking; at the same time, the working medium of the spring and automatic gap adjustment mechanism is changed from hydraulic oil to air, which can achieve advantages such as high reliability and stable output force; the piston and the insulation block are connected by threads, which is convenient for maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic diagram of the installation structure of a common wet piston in the prior art; Figure 2 It is a structural schematic diagram of the present invention; Figure 3 A schematic diagram of a pull rod according to the present invention; In the figure: 1-pull rod, 2-bushing, 3-piston, 4-support, 5-ball head, 6-insulation block, 7-nut, 8-rebound spring, 9-expansion tube, 10-first sealing ring, 11-first protective ring, 12-second sealing ring, 13-second protective ring, 101-end plate, 102-rod shaft. DETAILED DESCRIPTION

[0011] like Figures 2 to 3 As shown, a dry piston structure for aircraft wheel brakes includes a pull rod 1, a bushing 2 and a piston 3. The pull rod 1 includes an end plate 101 and a rod shaft 102. The piston 3 is slidably arranged in the inner cavity of the bushing 2. The end plate 101 of the pull rod 1 is installed in conjunction with the end face of the bushing 2. A through hole is provided on the end plate 101 of the pull rod 1 that is connected to the inner cavity of the bushing 2. The through hole is used to circulate hydraulic oil. A support 4 is provided in the inner cavity of the piston 3. A return spring 8 is provided on the outer sleeve of the support 4. The two ends of the return spring 8 respectively abut against the inner cavity end face of the piston 3 and the inner end face of the truncated cone of the support 4 to control the reset of the piston 3. An expansion tube 9 is provided in the inner hole of the support 4. The end of the expansion tube 9 away from the end plate 101 of the pull rod 1 is provided with a bell mouth, and the outer surface of the bell mouth extends The inner hole is against the support 4, and the rod shaft 102 in the middle of the pull rod 1 penetrates the expansion tube 9 and extends out of the bell mouth of the expansion tube 9. The rod shaft 102 of the pull rod 1 is located at the bell mouth of the expansion tube 9 and is sleeved with a ball head and a nut 7 is installed through a thread to limit the support 4. An insulating block 6 is provided at the opening of the inner cavity of the piston 3 to separate the high temperature generated by the brake from the components inside the piston 3. A first sealing ring 10 and a first protective ring 11 are provided between the rod shaft 102 of the pull rod 1 and the piston 3 to prevent hydraulic oil from entering the interior of the piston 3. The piston 3 is provided with an annular groove for installing the first sealing ring 10 and the first protective ring 11, so that the first sealing ring 10 and the first protective ring 11 move with the piston 3 to prevent hydraulic oil from entering the inner cavity of the piston 3.

[0012] The first sealing ring 10 and the first protective ring 11 are arranged in parallel, and the first protective ring 11 protects the first sealing ring 10 from being easily damaged or ineffective; multiple sets of second sealing rings 12 and second protective rings 13 are provided between the piston 3 and the bushing 2, two sets of which are shown in the figure, to effectively prevent the hydraulic oil from leaking from between the piston 3 and the bushing 2; the thermal insulation block 6 is installed on the piston 3 by means of threads, which facilitates the removal of the thermal insulation block 6 for inspection and maintenance of the components inside the piston 3; Working Principle: Brake hydraulic fluid enters the inner cavity of bushing 2 through the through-hole in tie rod 1, pushing piston 3 to move. A sealing ring and a protective ring are installed between piston 3 and tie rod 1 to prevent brake hydraulic fluid from entering the inner cavity of piston 3. When no brake hydraulic fluid pressure is input, the left end face contacts the inner end face of bushing 2. When braking, the hydraulic fluid pushes piston 3 toward the brake disc (to the right in the figure), compressing return spring 8. When the brake is released, the brake hydraulic fluid pressure is removed, and the compressed return spring 8 overcomes the residual pressure and friction in the hydraulic line to return piston 3 to its original position.

[0013] The return spring 8 is limited by the support 4, expansion tube 9, ball head and nut 7. It is required that when the elastic force of the return spring 8 is at its maximum, the expansion tube 9 must be able to withstand the elastic force transmitted by the support 4 without creeping. When the brake disc brakes due to wear, the piston 3 continues to move toward the brake disc, pushing the support 4 to overcome the expansion force and friction between the ball head and the expansion tube 9 and move forward, causing the expansion tube 9 to creep. The effective working length of the expansion tube 9 is equal to the total wear size allowed by the brake disc. When the brake disc is worn to the limit, the expansion tube 9 is also pulled out to the limit. When replacing the brake disc, the creeping expansion tube 9 is discarded. For this dry piston 3, the internal parts of the piston 3 can be replaced and inspected by simply unscrewing the insulation block 6, which is very convenient for maintenance.

[0014] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A dry piston structure for aircraft wheel brakes, comprising a pull rod (1), a bushing (2) and a piston (3), wherein the pull rod (1) comprises an end plate (101) and a rod shaft (102), and the piston (3) is slidably arranged in the inner cavity of the bushing (2), and the end plate (101) of the pull rod (1) is mounted in cooperation with the end face of the bushing (2), characterized in that: The end plate (101) of the pull rod (1) is provided with a through hole communicating with the inner cavity of the bushing (2), the inner cavity of the piston (3) is provided with a support (4), the outer sleeve of the support (4) is provided with a return spring (8), the two ends of the return spring (8) respectively abut against the inner cavity end face of the piston (3) and the inner end face of the cone of the support (4) to control the piston (3) to reset, the inner hole of the support (4) is provided with an expansion tube (9), the end of the expansion tube (9) away from the end plate (101) of the pull rod (1) is provided with a bell mouth, the outer surface of the bell mouth extends The rod shaft (102) in the middle of the pull rod (1) extends out of the expansion tube (9) and extends out of the bell mouth of the expansion tube (9). The rod shaft (102) of the pull rod (1) is located at the bell mouth of the expansion tube (9) and is provided with a ball head (5) and a nut (7) is installed through a thread. A heat insulation block (6) is provided at the opening of the inner cavity of the piston (3). A first sealing ring (10) and a first protective ring (11) are provided between the rod shaft (102) of the pull rod (1) and the piston (3).

2. The dry piston structure for aircraft wheel brakes according to claim 1, characterized in that: The piston (3) is provided with an annular groove for mounting a first sealing ring (10) and a first protective ring (11).

3. The dry piston structure for aircraft wheel brakes according to claim 1, characterized in that: The first sealing ring (10) and the first protective ring (11) are arranged in parallel.

4. The dry piston structure for aircraft wheel brakes according to claim 1, characterized in that: Multiple sets of second sealing rings (12) and second protective rings (13) are provided between the piston (3) and the bushing (2).

5. The dry piston structure for aircraft wheel brakes according to claim 1, characterized in that: The heat insulating block (6) is mounted on the piston (3) via threads.

Images