Rigid limiting structure used in rear shock absorber of turboprop engine

Abstract

The invention discloses a rigid limiting structure in a rear-side shock absorber, the rear-side shock absorber comprises a first rubber assembly, a second rubber assembly, a main support assembly and a mounting frame assembly, and a main bolt sequentially penetrates through the second rubber assembly, the main support assembly and the first rubber assembly and then is locked with a nut; a main bolt penetrating through the main support assembly is connected with one end of the installation frame assembly in a matched mode through a first ball bearing, the main support assembly comprises a main support frame body, and a third through hole is formed in the middle of the main support frame body. A first shaft sleeve and a second shaft sleeve are further connected outside the main bolt in a sleeved mode. The first shaft sleeve and the second shaft sleeve are both located in the third through hole, a gap H4 is reserved between the outer circumferential face of the first shaft sleeve and the inner circumferential face of the third through hole, and a gap H5 is reserved between the outer circumferential face of the second shaft sleeve and the inner circumferential face of the third through hole. When overlarge impact force or vibration is borne, the outer peripheral face of the first shaft sleeve and the outer peripheral face of the second shaft sleeve make contact with the inner peripheral face of the third through hole to form a rigid limiting structure.

Description

Technical Field

[0001] The present invention relates to a rigid limiting structure in a rear shock absorber, and more particularly to a rigid limiting structure in a rear shock absorber for a turboprop engine, belonging to the technical field of turboprop engine vibration reduction. Background Art

[0002] A turboprop engine is an engine that combines jet thrust and propeller thrust. It combines the characteristics of a jet engine and a propeller engine and has better performance in aspects such as low-speed flight and short takeoff and landing. Therefore, turboprop engines are widely used in aircraft such as small airplanes, helicopters, and unmanned aerial vehicles.

[0003] When a turboprop engine is operating, due to the rotation of the propeller, relatively large vibrations will be generated. Therefore, the vibration problem of a turboprop engine may be more prominent compared to other types of aeroengines. Vibration will have an adverse impact on the working performance of the engine itself, possibly causing wear and fatigue of engine components, thereby shortening its service life. At the same time, vibration will also cause damage to the aircraft airframe structure, such as inducing structural fatigue cracks, etc., and thus endangering the life and safety of the fuselage. Therefore, shock absorbers are generally installed between the engine and the aircraft frame to absorb and isolate vibration energy.

[0004] Along the length of the turboprop engine, the side close to the turboprop is set as the front side of the engine, and the opposite side is the rear side of the engine. After installing the shock absorber, according to its position relative to the engine, the shock absorber can be divided into a front shock absorber, a front upper shock absorber, and a rear shock absorber.

[0005] In the design of the rear shock absorber, it is necessary to design a rigid limiting structure because the rigid limiting structure can limit the degree of deformation of the shock absorber when it is subjected to excessive impact force or vibration, thereby protecting the shock absorber and the engine from damage; the rigid limiting structure can increase the stiffness of the shock absorber, making it more stable during operation and reducing the additional stress generated by vibration. In a turboprop engine shock absorber, the rigid limiting structure can also ensure that the shock absorber operates within a predetermined stroke range, avoiding failures or damages caused by exceeding the design range.

[0006] The Chinese invention patent application with the publication number CN116039935A and the publication date of May 2, 2023 discloses a vibration damping installation system for the engine of a large turboprop passenger aircraft, which includes: a turboprop engine having a front mounting surface near the propeller side and a rear mounting surface near the turbine combustion chamber side. There are two mounting points and three front mounting joints on the front mounting surface, and two rear mounting joints on the rear mounting surface. Among them, a mechanical or hydraulic torque compensation device is installed at the two mounting points; the three front mounting joints include a first front mounting joint and two second front mounting joints. The first front mounting joint is located at the vertex of the front mounting surface, and the two second front mounting joints are symmetrically arranged on the left and right along the longitudinal vertical plane of the engine. A front upper vibration damping device is installed at the first front mounting joint, and a front side vibration damping device is installed at the second front mounting joint; the two rear mounting joints are symmetrically arranged on the left and right along the longitudinal vertical plane of the engine, and a rear side vibration damping device is installed at the two rear mounting joints.

[0007] In this patent document, it does not disclose in detail how the rear side vibration damping device performs rigid limiting.

[0008] In summary, how to design a rigid limiting structure in the rear side shock absorber for a turboprop engine so that it can limit the deformation degree of the shock absorber when it is subjected to excessive impact force or vibration, thereby protecting the shock absorber and the engine from damage is a technical problem that needs to be solved urgently. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a rigid limiting structure in the rear side shock absorber for a turboprop engine to address the defects in the prior art. It can limit the deformation degree of the shock absorber when it is subjected to excessive impact force or vibration, thereby protecting the shock absorber and the engine from damage, ensuring that the shock absorber operates within a predetermined stroke range, and avoiding failures or damages caused by exceeding the design range.

[0010] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A rigid limiting structure in the rear shock absorber for a turboprop engine. The rear shock absorber includes a first rubber component, a second rubber component, a main bracket component disposed between the first rubber component and the second rubber component, and a mounting frame component disposed on one side of the main bracket component. One end of the mounting frame component is inserted into the main bracket component. A main bolt sequentially passes through the second rubber component, the main bracket component, and the first rubber component and is locked with a nut, thereby pressing the second rubber component and the first rubber component against the bottom surface and the top surface of the main bracket component, so that the rubber bodies in the second rubber component and the first rubber component are in a pre-compressed state. The main bolt passing through the main bracket component is connected to one end of the mounting frame component through a first ball bearing. The mounting frame component includes a mounting frame body, and a first ball bearing mounting hole is provided at one end of the mounting frame body. The main bracket component includes a main bracket frame body, and a third through hole is provided at the middle position on the main bracket frame body; when one end of the mounting frame component is inserted into one side of the main bracket component, the central axis of the first ball bearing mounting hole coincides with the central axis of the third through hole; after installation, the first ball bearing is disposed at the position between the rod body of the main bolt and the first ball bearing mounting hole, so that the main bolt passing through the main bracket component is connected to one end of the mounting frame component through the first ball bearing; A first sleeve and a second sleeve are also sleeved on the outside of the main bolt; the first sleeve is located at the position between the first rubber component and the first ball bearing, and the second sleeve is located at the position between the second rubber component and the first ball bearing; both the first sleeve and the second sleeve are located in the third through hole, and a gap H4 is left between the outer peripheral surface of the first sleeve and the inner peripheral surface of the third through hole, and a gap H5 is left between the outer peripheral surface of the second sleeve and the inner peripheral surface of the third through hole; When subjected to excessive impact force or vibration, a rigid limiting structure is formed by the contact between the outer peripheral surfaces of the first sleeve and the second sleeve and the inner peripheral surface of the third through hole.

[0011] Preferably, a second ball bearing mounting hole and a third ball bearing mounting hole are provided on the other side of the main bracket component. The ball bearing in the first screw rod with a ball bearing is the second ball bearing, and the ball bearing in the second screw rod with a ball bearing is the third ball bearing; after installation, the second ball bearing is disposed at the position between one end of the first screw rod and the second ball bearing mounting hole, so that one end of the first screw rod is connected to the other side of the main bracket component through the second ball bearing, and the third ball bearing is disposed at the position between one end of the second screw rod and the third ball bearing mounting hole, so that one end of the second screw rod is connected to the other side of the main bracket component through the third ball bearing. The other ends of the first screw rod and the second screw rod are both connected to the aircraft frame.

[0012] Preferably, a first mounting arm and a second mounting arm are provided on the aircraft frame. A first mounting through hole is provided at one end of the first mounting arm, and a second mounting through hole is provided at one end of the second mounting arm; During connection, the other end of the first screw rod passes through the first mounting through hole and is locked with the first mounting nut, and the other end of the second screw rod passes through the second mounting through hole and is locked with the second mounting nut, so that the other ends of the first screw rod and the second screw rod are both connected to the aircraft frame.

[0013] Preferably, both the second rubber component and the first rubber component include a top plate, a first bottom plate and a second bottom plate. The rubber bodies in the second rubber component and the first rubber component both include a first rubber stack and a second rubber stack. The first bottom plate is vulcanized and bonded to the top plate through the first rubber stack, and the second bottom plate is vulcanized and bonded to the top plate through the second rubber stack. The first rubber stack and the second rubber stack are respectively located at both ends of the top plate, and a through hole is formed in the middle position of the top plate. During installation, the main bolt sequentially passes through the through hole of the second rubber component, the main support component and the through hole of the first rubber component and is locked with a nut. After locking, the first bottom plate and the second bottom plate of the second rubber component are in contact with the bottom surface of the main support component, and the first bottom plate and the second bottom plate of the first rubber component are in contact with the top surface of the main support component.

[0014] Preferably, before pre-compression, one end of the first bushing is in contact with the top plate of the first rubber component, and there is a gap H1 between the other end of the first bushing and the end face of the inner ring of the first ball bearing. One end of the second bushing is in contact with the top plate of the second rubber component, and there is a gap H2 between the other end of the second bushing and the end face of the other end of the inner ring of the first ball bearing. After pre-compression by locking the main bolt, both the gap H1 and the gap H2 are zero.

[0015] Preferably, flanges are provided on the outer circumferential surfaces of one ends of the first bushing and the second bushing, and counterbores are provided on the top plates of the first rubber component and the second rubber component. When one ends of the first bushing and the second bushing are in contact with the top plate, the end portions of one ends of the first bushing and the second bushing are respectively inserted into the counterbores on the top plates of the first rubber component and the second rubber component, and the flanges on the end portions of one ends of the first bushing and the second bushing are respectively in contact with the top plates of the first rubber component and the second rubber component. At this time, there is a gap H3 between the end portions of one ends of the first bushing and the second bushing and the bottom surfaces of the counterbores on the top plates of the first rubber component and the second rubber component.

[0016] Preferably, a first through hole and a second through hole are further formed in the main support frame body, and a first positioning protrusion and a second positioning protrusion are respectively provided on the first bottom plate and the second bottom plate of the second rubber component and the first rubber component. The shapes of the first positioning protrusion and the second positioning protrusion match the first through hole and the second through hole. During installation, the positioning protrusion 1 and positioning protrusion 2 of the rubber component 1 are respectively inserted into one end of the through hole 1 and one end of the through hole 2 on the main support frame body, and the positioning protrusion 1 and positioning protrusion 2 of the rubber component 2 are respectively inserted into the other end of the through hole 1 and the other end of the through hole 2 on the main support frame body, so that the bottom plate 1 and bottom plate 2 of the rubber component 2 are in contact with the bottom surface of the main support assembly, and the bottom plate 1 and bottom plate 2 of the rubber component 1 are in contact with the top surface of the main support assembly.

[0017] The beneficial effects of the present invention are as follows: When subjected to excessive impact force or vibration, a rigid limiting structure is formed by the contact between the outer peripheral surface of the bushing 1 and the outer peripheral surface of the bushing 2 and the inner peripheral surface of the through hole 3, so that the present invention can limit the deformation degree of the shock absorber when subjected to excessive impact force or vibration, thereby protecting the shock absorber and the engine from damage, ensuring that the shock absorber works within a predetermined stroke range, and avoiding failures or damages caused by exceeding the design range. By designing the screw 1 with a ball bearing and the screw 2 with a ball bearing on the side of the rear shock absorber to connect the main support assembly to the aircraft frame, the rear shock absorber can obtain more installation redundancy in all directions, can compensate for the installation gap, and improves the safety, reliability and convenience of the installation and use of the rear shock absorber. The connection position of the main bolt is set at the position between the two rubber stacks of the rubber component 2 and the rubber component 1. In this way, as long as a main bolt is used to press the rubber component 2 and the rubber component 1 against the bottom surface and the top surface of the main support assembly, the rubber bodies in the rubber component 2 and the rubber component 1 can be pre-compressed. Therefore, compared with the prior art, the connection structure of one connecting bolt is reduced, the pre-compression structure of the rubber component is simplified, the installation steps are simplified, and the weight of the entire rear shock absorber device is reduced, meeting the requirements of lightweight design. In addition, by setting in this way, the area of the third metal skeleton in the prior art is also reduced, further reducing the weight of the entire rear shock absorber device. Using the positioning protrusion to cooperate with the through hole to assemble the rubber component and the main support component can further improve the assembly accuracy and assembly speed of the rear shock absorber; in addition, by opening the through hole 1 and the through hole 2, the weight of the main support frame body can also be reduced, further meeting the requirements of lightweight design. Description of the Drawings

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the rear shock absorber in the embodiment of the present invention; Figure 2 It is an exploded decomposition structural schematic diagram of the rear shock absorber in the embodiment of the present invention; Figure 3 It is an axial sectional structural schematic diagram of the rear shock absorber in the embodiment of the present invention; Figure 4 It is a three-dimensional structural schematic diagram of the main support assembly in the embodiment of the present invention; Figure 5Schematic three-dimensional structure diagram of the mounting frame assembly in the embodiment of the present invention; Figure 6 is Figure 3 Schematic diagram of a partial axial sectional structure at the main bolt in; Figure 7 is Figure 6 Enlarged structure diagram of part A in; Figure 8 Schematic three-dimensional structure diagram when the main support assembly and the aircraft frame are mounted and connected in the embodiment of the present invention; Figure 9 Schematic three-dimensional structure of rubber component one in the embodiment of the present invention Figure 1 ; Figure 10 Top view structure diagram of the rear shock absorber in the embodiment of the present invention; Figure 11 Schematic three-dimensional structure of rubber component one in the embodiment of the present invention Figure 2 ; Figure 12 is Figure 6 Enlarged structure diagram of part B in; In the figure: 1. Rubber component one, 2. Rubber component two, 3. Main support component, 311. Main support frame, 312. Through hole three, 313. Rotating arm, 314. Connecting arm, 315. Hanging ear, 316. Ball bearing two mounting hole, 317. Ball bearing three mounting hole, 318. Through hole one, 319. Through hole two, 4. Mounting frame component, 411. Mounting frame, 412. Ball bearing one mounting hole, 5. Main bolt, 6. Nut, 7. Ball bearing one, 711. Inner ring, 8. Screw rod one, 9. Screw rod two, 10. Screw, 11. Sleeve one, 12. Sleeve two, 13. Aircraft frame, 131. Mounting arm one, 132. Mounting arm two, 14. Mounting nut one, 15. Mounting nut two, 16. Connecting pin shaft, 17. Ball bearing two, 18. Ball bearing three, 19. Top plate, 191. Counterbore, 20. Bottom plate one, 21. Bottom plate two, 22. Rubber stack one, 23. Rubber stack two, 24. Positioning protrusion one, 25. Positioning protrusion two, 26. Flange, 27. Through hole. Detailed implementation manners

[0019] The technical solutions of the present invention will be further elaborated in detail below in conjunction with the drawings and specific embodiments.

[0020] Embodiment: As Figures 1 to 3As shown in the figure, the rear shock absorber in this embodiment includes a first rubber component 1, a second rubber component 2, a main bracket component 3 disposed between the first rubber component 1 and the second rubber component 2, and a mounting frame component 4 disposed on one side of the main bracket component 3. One end of the mounting frame component 4 is inserted into the main bracket component 3. The main bolt 5 passes through the second rubber component 2, the main bracket component 3, and the first rubber component 1 in sequence and is locked with the nut 6, thereby pressing the second rubber component 2 and the first rubber component 1 against the bottom surface and the top surface of the main bracket component 3, so that the rubber bodies in the second rubber component 2 and the first rubber component 1 are in a pre-compressed state. The main bolt 5 passing through the main bracket component 3 is connected with one end of the mounting frame component 4 through a first ball bearing 7. The other end of the mounting frame component 4 is connected to a turboprop engine (not shown in the figure), and the other side of the main bracket component 3 is connected to an aircraft frame (not shown in the figure) through a first screw 8 with a ball bearing and a second screw 9 with a ball bearing. By installing the above-mentioned rear shock absorber between the turboprop engine and the aircraft frame to absorb and isolate vibration energy, the service life of the turboprop engine is increased, and the safety of the aircraft body is ensured.

[0021] As Figure 4 and Figure 5 shown, the mounting frame component 4 includes a mounting frame body 411, and a first ball bearing mounting hole 412 is provided at one end of the mounting frame body 411. The main bracket component 3 includes a main bracket body 311, and a third through hole 312 is provided at the middle position of the main bracket body 311; As Figure 3 shown, when one end of the mounting frame component 4 is inserted into one side of the main bracket component 3, the central axis of the first ball bearing mounting hole 412 coincides with the central axis of the third through hole 312; after installation, the first ball bearing 7 is disposed at the position between the outer rod body of the main bolt 5 and the first ball bearing mounting hole 412, so that the main bolt 5 passing through the main bracket component 3 is connected with one end of the mounting frame component 4 through the first ball bearing 7. As Figure 5 shown, the other end of the mounting frame body 411 is connected to a turboprop engine (not shown in the figure) through a screw 10.

[0022] As Figure 6 and Figure 7As shown, a first sleeve 11 and a second sleeve 12 are also sleeved outside the main bolt 5; the first sleeve 11 is located between the first rubber component 1 and the first ball bearing 7, and the second sleeve 12 is located between the second rubber component 2 and the first ball bearing 7; both the first sleeve 11 and the second sleeve 12 are located in the third through hole 312, and a gap H4 is left between the outer peripheral surface of the first sleeve 11 and the inner peripheral surface of the third through hole 312, and a gap H5 is left between the outer peripheral surface of the second sleeve 12 and the inner peripheral surface of the third through hole 312. When subjected to excessive impact force or vibration, a rigid limiting structure is formed by the contact between the outer peripheral surfaces of the first sleeve 11 and the second sleeve 12 and the inner peripheral surface of the third through hole 312, so that in this embodiment, the deformation degree of the shock absorber when subjected to excessive impact force or vibration can be limited, thereby protecting the shock absorber and the engine from damage, ensuring that the shock absorber works within a predetermined stroke range, and avoiding faults or damages caused by exceeding the design range.

[0023] As Figure 4 and Figure 8 shown, a second ball bearing mounting hole 316 and a third ball bearing mounting hole 317 are provided on the other side of the main support assembly 3. The ball bearing in the screw rod one 8 with a ball bearing is the second ball bearing 17, and the ball bearing in the screw rod two 9 with a ball bearing is the third ball bearing 18; after installation, the second ball bearing 17 is arranged between one end of the screw rod one 8 and the second ball bearing mounting hole 316, so that one end of the screw rod one 8 is connected to the other side of the main support assembly 3 through the second ball bearing 17, and the third ball bearing 18 is arranged between one end of the screw rod two 9 and the third ball bearing mounting hole 317, so that one end of the screw rod two 9 is connected to the other side of the main support assembly 3 through the third ball bearing 18. The other ends of the screw rod one 8 and the screw rod two 9 are both connected to the aircraft frame 13. Through the above structure, the other side of the main support assembly 3 is connected to the aircraft frame 13 through the screw rod one 8 with a ball bearing and the screw rod two 9 with a ball bearing.

[0024] In this embodiment, the main support assembly is connected to the aircraft frame by designing the screw rod one with a ball bearing and the screw rod two with a ball bearing, so that the rear shock absorber can obtain more installation redundancy in all directions, can compensate for the installation gap, and improves the safety, reliability and convenience of the installation and use of the rear shock absorber.

[0025] An installation arm one 131 and an installation arm two 132 are provided on the aircraft frame 13. An installation through-hole one (not shown in the figure) is provided at one end of the installation arm one 131, and an installation through-hole two (not shown in the figure) is provided at one end of the installation arm two 132. When connecting, the other end of the screw one 8 is passed through the installation through-hole one and then locked with the installation nut one 14, and the other end of the screw two 9 is passed through the installation through-hole two and then locked with the installation nut two 15, so that the other ends of the screw one 8 and the screw two 9 are both connected to the aircraft frame 13.

[0026] The main support assembly 3 further includes a rotating arm 313. A connecting arm 314 and a hanging ear 315 are provided on one side of the main support frame body 311. The connecting arm 314 and the hanging ear 315 are of an integral structure with the main support frame body 311. One end of the rotating arm 313 is hinged to the hanging ear 315 through a connecting pin shaft 16. A ball bearing two mounting hole 316 is provided on the connecting arm 314, and a ball bearing three mounting hole 317 is provided at the other end of the rotating arm 313. Due to the influence of various factors, the relative positions between the installation through-hole one and the installation through-hole two on the aircraft frame 13 are not determined. Therefore, during connection in the prior art, the situation of difficult installation often occurs. In this embodiment, during installation, the screw one 8 with a ball bearing is first connected to the installation arm one. After connection, due to the hinged structure between the rotating arm 313 and the hanging ear 315, the installation position of the screw two 9 with a ball bearing can be adjusted according to the actual position of the installation through-hole two, so that the screw two 9 with a ball bearing can be conveniently connected to the installation arm two, thereby further improving the convenience of installation and use of the rear shock absorber. In addition, the connecting arm 314 and the main support frame body 311 are designed as an integral structure. In this way, compared with the prior art, one hinge point is reduced, so that the rear shock absorber is more stable during the shock absorption work.

[0027] The structures of the rubber component two 2 and the rubber component one 1 are the same. Taking the rubber component one 1 as an example, as Figure 9 shown, the rubber component one 1 includes a top plate 19, a bottom plate one 20 and a bottom plate two 21. The rubber body includes a rubber stack one 22 and a rubber stack two 23. The bottom plate one 20 is vulcanized and bonded to the top plate 19 through the rubber stack one 22, and the bottom plate two 21 is vulcanized and bonded to the top plate 19 through the rubber stack two 23. The rubber stack one 22 and the rubber stack two 23 are respectively located at both ends of the top plate 19. A through-hole 27 is opened at the middle position of the top plate 19. When installing, the main bolt 5 passes through the through-hole 27 of the rubber component two 2, the main support assembly 3 and the through-hole 27 of the rubber component one 1 in sequence and then is locked with the nut 6. After locking, the bottom plate one 20 and the bottom plate two 21 of the rubber component two 2 are in contact with the bottom surface of the main support assembly 3, and the bottom plate one 20 and the bottom plate two 21 of the rubber component one 1 are in contact with the top surface of the main support assembly 3. As Figure 10As shown, it can be seen that in this embodiment, the connection position of the main bolt 5 is set at the position between the two rubber stacks of the second rubber component 2 and the first rubber component 1. In this way, as long as one main bolt 5 is used to press the second rubber component 2 and the first rubber component 1 against the bottom surface and the top surface of the main bracket assembly 3, the rubber bodies in the second rubber component 2 and the first rubber component 1 can be pre-compressed. Thus, compared with the prior art, the connection structure of one connecting bolt is reduced, the pre-compression structure of the rubber component is simplified, the installation steps are simplified, and the weight of the entire rear shock absorber is reduced, meeting the requirements of lightweight design. In addition, with such a setting, the area of the third metal skeleton (i.e., the top plate in this embodiment) in the prior art is also reduced, further reducing the weight of the entire rear shock absorber.

[0028] As Figure 4 and Figure 11 shown, a first through hole 318 and a second through hole 319 are also formed in the main bracket frame 311. The first through hole 318 and the second through hole 319 are located on both sides of the third through hole 312. Positioning protrusions 24 and 25 are respectively arranged on the bottom plates 20 and 21 of the second rubber component 2 and the first rubber component 1. The shapes of the positioning protrusions 24 and 25 match those of the first through hole 318 and the second through hole 319. When the second rubber component 2 and the first rubber component 1 are pressed against the bottom surface and the top surface of the main bracket assembly 3, the positioning protrusions 24 and 25 of the first rubber component 1 are respectively inserted into one end of the first through hole 318 and one end of the second through hole 319 on the main bracket frame 311, and the positioning protrusions 24 and 25 of the second rubber component 2 are respectively inserted into the other end of the first through hole 318 and the other end of the second through hole 319 on the main bracket frame 311, thereby positioning the positions of the second rubber component 2 and the first rubber component 1 when they are pressed against the bottom surface and the top surface of the main bracket assembly 3. This can further improve the assembly accuracy and assembly speed of the rear shock absorber. In addition, the weight of the main bracket frame can also be reduced by the formed first through hole and second through hole, further meeting the requirements of lightweight design.

[0029] In addition, as Figure 6 and Figure 7As shown in the figure, in order to further precisely control the pre-compression amount of the rubber bodies in Rubber Component Two and Rubber Component One, the applicant has made further improvements. Before pre-compression, one end of the first bushing 11 contacts the top plate 19 of Rubber Component One, and there is a gap H1 between the other end of the first bushing 11 and the end face of one end of the inner ring 711 of the first ball bearing 7. One end of the second bushing 12 contacts the top plate 19 of Rubber Component Two, and there is a gap H2 between the other end of the second bushing 12 and the end face of the other end of the inner ring 711 of the first ball bearing 7. After the main bolt 5 is tightened for pre-compression, both the gap H1 and the gap H2 become zero, that is, the other end of the first bushing 11 contacts the end face of one end of the inner ring 711 of the first ball bearing 7, and the other end of the second bushing 12 contacts the end face of the other end of the inner ring 711 of the first ball bearing 7. In this way, by using the rigid limit between the bushing and the ball bearing, the pre-compression amount of the rubber bodies in Rubber Component Two and Rubber Component One can be precisely controlled by designing the values of the gaps H1 and H2. After the bolt and nut reach the designed tightening torque, the bushing generates metal rigid limit to ensure the designed compression state of the rubber, ensuring that the rubber parts do not loosen under the engine load condition of the rear shock absorber. In addition, it should be noted that after pre-compression, the first bushing and the second bushing can also be used to axially limit the ball bearing.

[0030] As Figure 12 shown, on the outer peripheral surface of one end of the first bushing 11 and the second bushing 12, flanges 26 are provided respectively. On the top plates 19 of Rubber Component One and Rubber Component Two, counterbores 191 are provided respectively. When one end of the first bushing 11 and the second bushing 12 contacts the top plate 19, the end parts of one end of the first bushing 11 and the second bushing 12 are respectively inserted into the counterbores 191 on the top plates 19 of Rubber Component One and Rubber Component Two, and the flanges 26 on the end parts of one end of the first bushing 11 and the second bushing 12 contact the top plates 19 of Rubber Component One and Rubber Component Two respectively. At this time, there is a gap H3 between the end parts of one end of the first bushing 11 and the second bushing 12 and the bottom surfaces of the counterbores 191 on the top plates 19 of Rubber Component One and Rubber Component Two.

[0031] In summary, when subjected to excessive impact or vibration, a rigid limiting structure is formed by the contact between the outer peripheral surfaces of the first bushing and the second bushing and the inner peripheral surface of the third through hole, so that the present invention can limit the deformation degree of the shock absorber when subjected to excessive impact or vibration, thereby protecting the shock absorber and the engine from damage, ensuring that the shock absorber operates within a predetermined stroke range, and avoiding failures or damages caused by exceeding the design range. By designing the first screw rod with a ball bearing and the second screw rod with a ball bearing on the side of the rear shock absorber to connect the main bracket assembly to the aircraft frame, the rear shock absorber can obtain more installation redundancy in all directions, compensate for the installation gap, and improve the safety, reliability and convenience of the installation and use of the rear shock absorber. The connection position of the main bolt is set at the position between the two rubber piles of the second rubber component and the first rubber component. In this way, as long as a main bolt is used to press the second rubber component and the first rubber component against the bottom surface and the top surface of the main bracket assembly, the rubber bodies in the second rubber component and the first rubber component can be pre-compressed. Therefore, compared with the prior art, the connection structure of one connecting bolt is reduced, the pre-compression structure of the rubber component is simplified, the installation steps are simplified, and the weight of the entire rear shock absorber device is reduced, meeting the requirements of lightweight design. In addition, with this setting, the area of the third metal skeleton in the prior art is also reduced, further reducing the weight of the entire rear shock absorber device. Using the positioning protrusions to cooperate with the through holes to assemble the rubber component and the main bracket component can further improve the assembly accuracy and assembly speed of the rear shock absorber; in addition, the weight of the main bracket frame can also be reduced by the opened first through hole and the second through hole, thereby further meeting the requirements of lightweight design.

[0032] "A plurality of" as described in the embodiments refers to a quantity of "two or more". The above embodiments are only for illustrating the present invention and not for limiting the present invention. Those skilled in the relevant technical fields can make various changes or transformations without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the present invention, and the protection scope of the present invention should be defined by each claim.

Claims

1. A rigid limit structure for a rear shock absorber of a turboprop engine, the rear shock absorber comprising a rubber component 1, a rubber component 2, a main bracket component arranged between the rubber component 1 and the rubber component 2, and a mounting frame component arranged at one side of the main bracket component, one end of the mounting frame component is inserted into the main bracket component, a main bolt is sequentially passed through the rubber component 2, the main bracket component and the rubber component 1 and then locked with a nut, so that the rubber component 2 and the rubber component 1 are pressed against the bottom surface and the top surface of the main bracket component, so that the rubber bodies in the rubber component 2 and the rubber component 1 are in a pre-compressed state, the main bolt passing through the main bracket component is matched and connected with one end of the mounting frame component through a ball bearing 1, characterized in that: The mounting frame assembly includes a mounting frame body, a ball bearing 1 mounting hole is arranged at one end of the mounting frame body, and the main bracket assembly includes a main bracket frame body, and a through hole 3 is arranged at the middle position of the main bracket frame body; when one end of the mounting frame assembly is inserted into one side of the main bracket assembly, the central axis of the ball bearing 1 mounting hole and the central axis of the through hole 3 coincide with each other; after installation, the ball bearing 1 is arranged at a position between the outside of the rod body of the main bolt and the ball bearing 1 mounting hole, so that the main bolt passing through the main bracket assembly is connected with one end of the mounting frame assembly through the ball bearing 1; A sleeve 1 and a sleeve 2 are sleeved on the outside of the main bolt; the sleeve 1 is located between the rubber component 1 and the ball bearing 1, and the sleeve 2 is located between the rubber component 2 and the ball bearing 1; the sleeve 1 and the sleeve 2 are both located in the through hole 3, and a gap H4 is left between the outer circumference of the sleeve 1 and the inner circumference of the through hole 3, and a gap H5 is left between the outer circumference of the sleeve 2 and the inner circumference of the through hole 3; When subjected to excessive impact force or vibration, a rigid limiting structure is formed by the contact between the outer circumference of the shaft sleeve one and the outer circumference of the shaft sleeve two and the inner circumference of the through hole three.

2. The rigid limiting structure according to claim 1, characterized in that: A ball bearing two mounting hole and a ball bearing three mounting hole are provided on the other side of the main bracket assembly. The ball bearing in the screw rod one with the ball bearing is ball bearing two, and the ball bearing in the screw rod two with the ball bearing is ball bearing three. After installation, ball bearing two is arranged at a position between one end of the screw rod one and the ball bearing two mounting hole, so that one end of the screw rod one is matched and connected with the other side of the main bracket assembly through ball bearing two, and ball bearing three is arranged at a position between one end of the screw rod two and the ball bearing three mounting hole, so that one end of the screw rod two is matched and connected with the other side of the main bracket assembly through ball bearing three, and the other ends of the screw rod one and the screw rod two are both connected to the aircraft frame.

3. The rigid limiting structure according to claim 2, characterized in that: A mounting arm 1 and a mounting arm 2 are provided on the aircraft frame, a mounting through hole 1 is provided on one end of the mounting arm 1, and a mounting through hole 2 is provided on one end of the mounting arm 2; When connecting, the other end of screw rod one is passed through installation through hole one and then locked with installation nut one, and the other end of screw rod two is passed through installation through hole two and then locked with installation nut two, so that the other ends of screw rod one and screw rod two are connected to the aircraft frame.

4. The rigid limiting structure according to claim 1, 2 or 3, characterized in that: The rubber component 2 and the rubber component 1 both include a top plate, a bottom plate 1 and a bottom plate 2, the rubber bodies in the rubber component 2 and the rubber component 1 both include a rubber pile 1 and a rubber pile 2, the bottom plate 1 is vulcanized and bonded to the top plate through the rubber pile 1, the bottom plate 2 is vulcanized and bonded to the top plate through the rubber pile 2, the rubber pile 1 and the rubber pile 2 are respectively located at the two ends of the top plate, and a through hole is opened in the middle of the top plate; During installation, the main bolt passes through the through hole of rubber component 2, the main bracket component and the through hole of rubber component 1 in sequence and is then locked with the nut. After locking, the bottom plate 1 and bottom plate 2 of rubber component 2 are in contact with the bottom surface of the main bracket component, and the bottom plate 1 and bottom plate 2 of rubber component 1 are in contact with the top surface of the main bracket component.

5. The rigid limiting structure according to claim 4, characterized in that: Before pre-compression, one end of the sleeve one contacts the top plate of the rubber component one, and a gap H1 is left between the other end of the sleeve one and the end face of one end of the inner ring of the ball bearing one; one end of the sleeve two contacts the top plate of the rubber component two, and a gap H2 is left between the other end of the sleeve two and the end face of the other end of the inner ring of the ball bearing one; when the main bolt is tightened for pre-compression, the gaps H1 and H2 are both zero.

6. The rigid limiting structure according to claim 5, characterized in that: A flange is provided on the outer peripheral surface of one end of the shaft sleeve 1 and the shaft sleeve 2, and a countersunk hole is provided on the top plate of the rubber component 1 and the rubber component 2; When one end of the sleeve 1 and the sleeve 2 contacts with the top plate, one end of the sleeve 1 and the sleeve 2 is respectively inserted into the countersunk holes on the top plates of the rubber components 1 and 2, and the flanges on one end of the sleeve 1 and the sleeve 2 are respectively contacted with the top plates of the rubber components 1 and 2. At this time, a gap H3 is left between one end of the sleeve 1 and the sleeve 2 and the bottom surface of the countersunk holes on the top plates of the rubber components 1 and 2.

7. The rigid limiting structure according to claim 4, characterized in that: A through hole 1 and a through hole 2 are also provided on the main support frame, and a positioning protrusion 1 and a positioning protrusion 2 are respectively provided on the bottom plate 1 and the bottom plate 2 of the rubber component 2 and the rubber component 1, and the shapes of the positioning protrusion 1 and the positioning protrusion 2 match the through hole 1 and the through hole 2; During installation, the positioning protrusion 1 and the positioning protrusion 2 of the rubber component 1 are respectively inserted into one end of the through hole 1 and one end of the through hole 2 on the main bracket frame, and the positioning protrusion 1 and the positioning protrusion 2 of the rubber component 2 are respectively inserted into the other end of the through hole 1 and the other end of the through hole 2 on the main bracket frame, so that the bottom plate 1 and the bottom plate 2 of the rubber component 2 are in contact with the bottom surface of the main bracket assembly, and the bottom plate 1 and the bottom plate 2 of the rubber component 1 are in contact with the top surface of the main bracket assembly.

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