A high-thrust and high-speed axial force loading device

Abstract

The present invention belongs to the technical field of aviation test instruments, and specifically relates to a high-thrust and high-speed axial force loading device. The present invention is an independent box body, without axial positioning, and has the function of automatically compensating for axial displacement. The axial force is provided by a double-rod hydraulic cylinder and transmitted by a tilting pad thrust bearing. The present invention can stably provide an axial force from zero to the rated load by accurately controlling the oil supply pressure of the double-rod hydraulic cylinder, with high loading accuracy and a small load fluctuation range; a radial force is applied to the drive shaft by a double-rod hydraulic cylinder arranged above the box body to increase the support stiffness of the cylindrical roller bearing. When the drive shaft rotates at a high speed over a critical value, the radial force is changed, thereby changing the support stiffness of the cylindrical roller bearing, and then changing the natural frequency of the shaft system, and having the function of frequency shifting. The present invention has the characteristics of strong operability, high speed, large thrust and strong practicality.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation testers, and in particular relates to a large-thrust and high-speed axial force loading device. Background Art

[0002] The high-speed rotors of aircraft engines are supported by elastic supports and squeeze film dampers. The GE90 and GEnx engines use this design to reduce the vibration of the rotor when it passes the critical speed. However, the performance of the squeeze film damper cannot be accurately calculated based on the design parameters, and a trial and error method based on experience, theory and experiment is required.

[0003] In order to more effectively play the shock-absorbing role of the squeeze film damper, it is necessary to conduct tests and verifications on the squeeze film damper and the rotor system together to match a suitable squeeze film damper. When the rotor system rotates at high speed, the compressor rotor blades do work on the air, causing the blades to be subjected to the reaction force of the airflow, and the direction of the force is axial. The bearing that bears the axial force is a three-point ball bearing, which can only work stably under the condition of axial force. Therefore, during the test, an external axial force loading device is required, and the axial force is transmitted to the three-point ball bearing of the rotor system through a coupling.

[0004] Aircraft engines have high transmission power and high operating speed, and generate large axial thrust. The existing axial force loading method cannot meet the axial force requirements. Summary of the invention

[0005] The object of the present invention is to provide a high-thrust and high-speed axial force loading device.

[0006] A high-thrust, high-speed axial force loading device comprises a housing and a double-rod hydraulic cylinder; a housing bushing is installed on the housing, and a transmission shaft, a cylindrical roller bearing, a tilting pad thrust bearing, and a thrust bearing seat are arranged inside the housing; the inner ring of the cylindrical roller bearing is installed at both ends of the transmission shaft, and the outer ring of the cylindrical roller bearing is installed on the housing; the transmission shaft is supported by the cylindrical roller bearing, and a thrust plate is arranged in the middle of the transmission shaft; the tilting pad thrust bearing is sleeved on the transmission shaft, and the tilting pad block on its end face contacts the thrust plate of the transmission shaft; the thrust bearing seat is sleeved on the tilting pad thrust bearing, and a cylindrical pin is installed radially between the thrust bearing seat and the tilting pad thrust bearing to prevent rotation when transmitting the axial force; a plurality of the double-rod hydraulic cylinders are installed on the housing bushing, evenly distributed along the circumference of the transmission shaft, and are used to apply axial force to the thrust bearing seat and rely on the housing wall to bear the reaction force of the axial force; another double-rod hydraulic cylinder is installed above the housing to apply radial force to the thrust bearing seat.

[0007] Furthermore, a drum-shaped tooth is installed at one end of the transmission shaft to compensate for the axial displacement after the axial force is applied. A cover shell is provided outside the drum-shaped tooth, and the cover shell is installed on the housing bushing. An oil supply pipe and an oil return pipe for lubricating the drum-shaped tooth are provided on the cover shell.

[0008] Furthermore, the multiple double-rod hydraulic cylinders evenly distributed along the circumference of the transmission shaft are connected in parallel and share one oil inlet and one oil outlet. When loading, the oil supply pressure of each double-rod hydraulic cylinder is consistent, and the input force remains consistent, so as to avoid unbalanced loading of the tilting pad of the tilting pad thrust bearing, which would cause additional overturning moment of the transmission shaft. The double-rod hydraulic cylinders arranged above the box body are used to adjust the support stiffness of the cylindrical roller bearing and change the natural frequency of the shaft system when working at a high speed beyond the critical point.

[0009] Furthermore, the tilting pad thrust bearing is composed of a tilting pad on the end face and four oils in the inner hole; after the transmission shaft rotates, the tilting pad contacts the thrust plate of the transmission shaft to form a dynamic pressure oil film, and the journal of the transmission shaft cooperates with the four oils in the inner hole, so that the tilting pad thrust bearing can move freely on the transmission shaft without getting stuck, so that the applied axial force is fully borne by the transmission shaft.

[0010] Furthermore, each extension rod head of the double-rod hydraulic cylinder is equipped with a force sensor for detecting the output force value. The oil supply pressure of the double-rod hydraulic cylinder is controlled by a proportional servo valve so that it can stably provide an axial force from zero to rated load, with high loading accuracy and a small load fluctuation range.

[0011] The beneficial effects of the present invention are:

[0012] The present invention is an independent box body, without axial positioning, and has the function of automatically compensating for axial displacement. The axial force is provided by a double-rod hydraulic cylinder and transmitted by a tilting pad thrust bearing. The present invention can stably provide an axial force from zero to the rated load by accurately controlling the oil supply pressure of the double-rod hydraulic cylinder, with high loading accuracy and a small load fluctuation range. The double-rod hydraulic cylinder arranged above the box body applies radial force to the transmission shaft to increase the support stiffness of the cylindrical roller bearing. When the transmission shaft rotates at a high speed over a critical value, the radial force is changed, thereby changing the support stiffness of the cylindrical roller bearing, and then changing the natural frequency of the shaft system, and has the function of frequency shifting. The present invention has the characteristics of strong operability, high speed, large thrust and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an overall schematic diagram of the present invention.

[0014] Figure 2 It is a schematic diagram of the tilting pad thrust bearing in the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings.

[0016] Embodiment 1:

[0017] A high-thrust, high-speed axial force loading device, comprising a box body and a double-rod hydraulic cylinder 3; a box body bushing 5 is installed on the box body, and a transmission shaft 2, a cylindrical roller bearing 4, a tilting pad thrust bearing 7, and a thrust bearing seat 8 are arranged inside the box body; the inner ring of the cylindrical roller bearing 4 is installed at both ends of the transmission shaft 2, and the outer ring of the cylindrical roller bearing 4 is installed on the box body; the transmission shaft 2 is supported by the cylindrical roller bearing 4, and a thrust plate is arranged in the middle of the transmission shaft 2; the tilting pad thrust bearing 7 is sleeved on the transmission shaft 2, and its end face The tilting pad is in contact with the thrust plate of the transmission shaft 2; the thrust bearing seat 8 is mounted on the tilting pad thrust bearing 7, and a cylindrical pin is installed radially between the thrust bearing seat 8 and the tilting pad thrust bearing 7 to prevent rotation when transmitting axial force; multiple double-rod hydraulic cylinders 3 are installed on the box bushing 5 and are evenly distributed along the circumference of the transmission shaft 2, and are used to apply axial force to the thrust bearing seat 8 and rely on the box wall to withstand the reaction force of the axial force; another double-rod hydraulic cylinder 3 is installed above the box to apply radial force to the thrust bearing seat 8.

[0018] The present invention is an independent housing. The supporting bearings at both ends of the axial force loading device are cylindrical roller bearings 4. The two ends are connected to the external coupling through a flange structure. The generated axial force is transmitted to the high-speed rotor by the coupling. Therefore, this axial force loading device has no axial positioning and has the function of automatically compensating for axial displacement when transmitting axial force. The axial force loading device mainly relies on the tilting pad thrust bearing 7 to transmit the axial force. The specific bearing parameters are determined by the working conditions. The tilting pad thrust bearing 7 uses the dynamic pressure oil film formed between the tilting pad and the thrust plate to realize large-tonnage axial force transmission and can accurately adjust the axial loading force.

[0019] Embodiment 2:

[0020] Furthermore, a drum-shaped gear 10 is installed at one end of the transmission shaft 2 for compensating for the axial displacement after the axial force is applied. A cover shell 11 is provided outside the drum-shaped gear 10, and the cover shell 11 is installed on the housing bushing 5. The cover shell 11 is provided with an oil supply pipe and an oil return pipe for lubricating the drum-shaped gear.

[0021] Embodiment 3:

[0022] In the present invention, the axial force is provided by a double-rod hydraulic cylinder 3, a force sensor 6 is installed at the head of the rod, and the oil supply pressure of the double-rod hydraulic cylinder 3 is controlled by a proportional servo valve, which can stably provide an axial force from zero to a rated load, with high loading accuracy and a small load fluctuation range; a plurality of double-rod hydraulic cylinders 3 evenly distributed circumferentially along the transmission shaft 2 are connected in parallel, sharing an oil inlet and an oil outlet, and the oil supply pressures of the double-rod hydraulic cylinders 3 are consistent during loading, and the input force is kept consistent, thereby avoiding unbalanced loading of the tilting pad of the tilting pad thrust bearing 7, and the transmission shaft 2 does not generate additional overturning moment due to the application of the axial force.

[0023] The double-rod hydraulic cylinder 3 arranged above the box in the present invention is used to apply radial force to the transmission shaft 2, increase the support stiffness of the cylindrical roller bearing 4, and change the radial force when the transmission shaft 2 rotates at a high speed over a critical value, thereby changing the support stiffness of the cylindrical roller bearing 4, and then changing the natural frequency of the shaft system, which has the function of frequency shifting. At the same time, since the oil film of the sliding bearing has a damping characteristic, it can absorb the vibration of the shaft system.

[0024] Embodiment 4:

[0025] Furthermore, the tilting pad thrust bearing 7 is composed of a tilting pad on the end face and four oils in the inner hole; after the transmission shaft 2 rotates, the tilting pad contacts the thrust plate of the transmission shaft 2 to form a dynamic pressure oil film, and the journal of the transmission shaft 2 cooperates with the four oils in the inner hole, so that the tilting pad thrust bearing 7 can move freely on the transmission shaft 2 without getting stuck, so that the applied axial force is fully borne by the transmission shaft 2.

[0026] Embodiment 5:

[0027] like Figure 1 As shown, the axial force loading device described in the present invention adopts an independent box design, which is composed of a lower box 1 and an upper box. A box bushing 5 is installed on the box, and a double-rod hydraulic cylinder 3 is installed on the bushing; the reaction force after the axial force is applied acts on the box bushing 5 and is transmitted to the box through the box bushing 5.

[0028] The supporting bearings at both ends of the axial force loading device are cylindrical roller bearings 4, which are connected to the external coupling through a flange structure. The generated axial force is transmitted to the high-speed rotor by the coupling; therefore, this axial force loading device has no axial positioning, and the initial installation position needs to be limited during the assembly process. The displacement of the transmission shaft caused by the axial force is compensated by the drum-shaped teeth composed of the cylindrical roller bearing 4, the drum-shaped teeth 10, and the internal teeth 12, avoiding the axial force of the accompanying test equipment. At the same time, the drum-shaped teeth here also serve as one of the hinges of the coupling, playing a role in angular compensation.

[0029] The tilting pad thrust bearing 7 with a four-oil structure in the inner hole is mounted on the transmission shaft 2, and relies on the dynamic pressure oil film formed by the tilting pad to transmit large thrust, and relies on the four oils to provide radial support for the bearing. After the transmission shaft 2 rotates, an oil film is formed. At the same time, the tilting pad thrust bearing can also move freely on the shaft without getting stuck, so that the applied axial force is fully borne by the transmission shaft 2.

[0030] The double-rod hydraulic cylinders 3 are evenly distributed on the circumference of the casing bushing. Multiple hydraulic cylinders act on the thrust bearing seat 8 at the same time. The hydraulic cylinders are connected in parallel and share one oil inlet and one oil outlet. When loading, the oil supply pressure of each hydraulic cylinder is consistent, and the input force is kept consistent to avoid eccentric loading of the tilting pad and additional overturning moment of the transmission shaft. The hydraulic cylinder at the upper casing 9 is used to adjust the support stiffness of the cylindrical roller bearing 4 and change the natural frequency of the shaft system when working at high speed and overcritical.

[0031] The design process of the axial force loading device of the present invention is as follows:

[0032] 1. Analyze the working mechanism of the axial force loading device and master the core technology of the design of high linear speed tilting pad thrust bearings;

[0033] 2. By designing the structure of the axial force loading device, determine the cylindrical roller bearings, transmission shafts with thrust plates, and tilting pad thrust bearings that meet the power and speed requirements; then complete the design of the loading bearing seat, housing, and hydraulic cylinder to confirm the overall structure;

[0034] 3. Through the analysis of the device, calculate the number of pads, average specific pressure, average linear speed, oil film thickness, oil film temperature, and lubricating oil volume of the tilting pad thrust bearing under high power and high speed conditions, and determine the structure and size of the tilting pad thrust bearing and its thrust pads;

[0035] 4. Grind machine samples and conduct load tests on the device to verify the device's high speed capability and high thrust axial force loading function.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-thrust and high-speed axial force loading device, characterized in that: It comprises a housing and a double-rod hydraulic cylinder (3); a housing bushing (5) is installed on the housing, and a transmission shaft (2), a cylindrical roller bearing (4), a tilting pad thrust bearing (7), and a thrust bearing seat (8) are arranged inside the housing; the inner ring of the cylindrical roller bearing (4) is installed at both ends of the transmission shaft (2), and the outer ring of the cylindrical roller bearing (4) is installed on the housing; the transmission shaft (2) is supported by the cylindrical roller bearing (4), and the two ends of the axial force loading device are connected to the external coupling through a flange structure, and the generated axial force is transmitted to the high-speed rotor by the coupling, and a thrust plate is arranged in the middle of the transmission shaft (2); the tilting pad thrust shaft The bearing (7) is sleeved on the transmission shaft (2), and the tilting pad on its end face contacts the thrust plate of the transmission shaft (2); the thrust bearing seat (8) is sleeved on the tilting pad thrust bearing (7), and a cylindrical pin is installed in the radial direction between the thrust bearing seat (8) and the tilting pad thrust bearing (7) to prevent rotation when transmitting axial force; a plurality of double-rod hydraulic cylinders (3) are installed on the housing bushing (5) and evenly distributed along the circumference of the transmission shaft (2), and are used to apply axial force to the thrust bearing seat (8) and rely on the housing wall to bear the reaction force of the axial force; another double-rod hydraulic cylinder (3) is installed above the housing to apply radial force to the thrust bearing seat (8).

2. A high-thrust, high-speed axial force loading device according to claim 1, characterized in that: A drum-shaped tooth (10) is installed at one end of the transmission shaft (2) for compensating for axial displacement after an axial force is applied. A cover shell (11) is provided outside the drum-shaped tooth (10). The cover shell (11) is installed on the housing bushing (5). An oil supply pipe and an oil return pipe for lubricating the drum-shaped tooth are provided on the cover shell (11).

3. The high-thrust and high-speed axial force loading device according to claim 1 is characterized in that: The plurality of double-rod hydraulic cylinders (3) uniformly distributed along the circumference of the transmission shaft (2) are connected in parallel and share an oil inlet and an oil outlet. When loaded, the oil supply pressure of each double-rod hydraulic cylinder (3) is consistent, and the input force is kept consistent, so as to avoid the tilting pad of the tilting pad thrust bearing (7) from being overloaded, and prevent the transmission shaft (2) from generating an additional overturning moment due to the application of the axial force. The double-rod hydraulic cylinder (3) arranged above the box body is used to adjust the support stiffness of the cylindrical roller bearing (4) and change the natural frequency of the shaft system when working at a high speed and over a critical level.

4. The high-thrust and high-speed axial force loading device according to claim 1 is characterized in that: The tilting pad thrust bearing (7) is composed of a tilting pad block on the end surface and four oil liquids in the inner hole. After the transmission shaft (2) rotates, the tilting pad block contacts the thrust plate of the transmission shaft (2) to form a dynamic pressure oil film, and the journal of the transmission shaft (2) cooperates with the four oil liquids in the inner hole, so that the tilting pad thrust bearing (7) can move freely on the transmission shaft (2) without being stuck, so that the applied axial force is completely borne by the transmission shaft (2).

5. The high-thrust and high-speed axial force loading device according to claim 1 is characterized in that: Each extension rod head of the double-rod hydraulic cylinder (3) is equipped with a force sensor (6) for detecting the output force value. The oil supply pressure of the double-rod hydraulic cylinder (3) is controlled by a proportional servo valve so that the double-rod hydraulic cylinder (3) can stably provide an axial force from zero to a rated load, with high loading accuracy and a small load fluctuation range.

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