Fatigue test device for elastic connecting rod coupling and test method thereof

Abstract

The invention discloses a fatigue test device for an elastic connecting rod coupling and a test method thereof, and relates to the technical field of elastic connecting rod couplings. The invention aims to solve the problem that the fatigue strength test of the elastic connecting rod coupling cannot be completed by the existing test device. The testing device comprises a torsion shaft disc, a force arm assembly, a transmission shaft, a fixing support, a transmission assembly, a servo motor and a plurality of bearing seats, the servo motor drives the transmission assembly to reciprocate in the vertical direction, the lower end of the transmission assembly is rotationally connected with the outer side end of the force arm assembly, and the inner side end of the force arm assembly is fixedly connected with the torsion shaft disc. The torsion shaft disc is horizontally arranged through the bearing seat, the inner side end of the torsion shaft disc is fixedly connected with the input end of the elastic connecting rod coupler, the output end of the elastic connecting rod coupler is fixedly connected with the inner side end of the transmission shaft, the transmission shaft is horizontally arranged through the bearing seat, and the outer side end of the transmission shaft is fixedly connected with the fixing support. The device is used for the fatigue test of the elastic connecting rod coupling.

Description

Technical Field

[0001] This invention relates to the field of flexible connecting rod coupling technology, and more specifically to a fatigue testing device and method for flexible connecting rod couplings. Background Technology

[0002] Flexible connecting rod couplings are widely used in marine propulsion systems, wind power generation, engine test benches, and other fields. They offer functions such as torque transmission, displacement compensation, vibration damping, and compact structure. They mainly consist of an input flange, an output flange, an intermediate shaft, and a flexible connecting rod assembly. Chinese patent CN206129865U describes a flexible connecting rod assembly composed of a connecting rod casting, spherical rubber joints, and cylindrical rubber joints. The advantage of these rubber joints is that they absorb the impact of vibrations in the power system and compensate for axial, angular, and radial deformations caused by misalignment and thermal expansion of the main engine. The disadvantage is that these rubber joints will wear and even fatigue during use, which is unavoidable. Therefore, rubber components are usually defined as lifespan parts in engineering and must be replaced promptly when they reach their specified service life.

[0003] As is well known, under repeated dynamic strain, rubber materials will gradually develop microscopic damage inside and accumulate continuously, eventually leading to a decrease in the mechanical properties of rubber, such as strength and elasticity, and the appearance of cracks or even fractures on the surface, thus causing fatigue aging.

[0004] In summary, fatigue testing is an indispensable and crucial step in the development of flexible connecting rod couplings. Cyclic fatigue tests are performed hundreds of thousands or even millions of times within a given frequency and torque range to verify the dynamic performance of the flexible connecting rod coupling. Therefore, there is an urgent need to invent a device and method for fatigue testing of flexible connecting rod couplings. Summary of the Invention

[0005] In order to solve the problem that existing testing devices cannot complete fatigue strength tests on elastic connecting rod couplings, this invention proposes a fatigue testing device and method for elastic connecting rod couplings.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] A fatigue testing device for an elastic linkage coupling includes a torsion disc, a lever arm assembly, a transmission shaft, a fixed bracket, a transmission component, a servo motor, and multiple bearing seats. The servo motor drives the transmission component to reciprocate vertically. The lower end of the transmission component is rotatably connected to the outer end of the lever arm assembly. The inner end of the lever arm assembly is fixedly connected to the torsion disc. The torsion disc is horizontally positioned via the bearing seats. The inner end of the torsion disc is fixedly connected to the input end of the elastic linkage coupling. The output end of the elastic linkage coupling is fixedly connected to the inner end of the transmission shaft. The transmission shaft is horizontally positioned via the bearing seats, and the outer end of the transmission shaft is fixedly connected to the fixed bracket.

[0008] The transmission assembly includes a first pull rod, a second pull rod, and a third pull rod. The upper end of the first pull rod is connected to the output end of the servo motor. The lower end of the first pull rod is fixed to the upper end of the second pull rod by a first fastener. The middle part of the third pull rod is horizontally inserted into the lower end of the second pull rod and is rotatably connected to the second pull rod. The two ends of the third connecting rod are fixed to the outer ends of the lever arm assembly by second fasteners.

[0009] The middle part of the third tie rod is rotatably connected to the second tie rod via a rolling bearing.

[0010] The inner end of the lever arm assembly is fixed to the torsion shaft disk by a third fastener.

[0011] The torsion shaft disc includes a torsion disc and a torsion shaft. The torsion shaft is horizontally positioned, and the torsion disc is fixed to the outer end of the torsion shaft. A through hole is provided on the side wall of the torsion shaft, and the end of the third fastener is inserted into the through hole.

[0012] Multiple reinforcing ribs are evenly distributed and fixed between the torsion disc and the torsion shaft along the circumferential direction.

[0013] The inner end of the torsion shaft is fixedly connected to the input flange of the elastic connecting rod coupling via the input side flange, the inner end of the drive shaft is fixedly connected to the output flange of the elastic connecting rod coupling via the output side flange, and the outer end of the drive shaft is fixedly connected to the fixed bracket via the connecting flange.

[0014] The bearing housing includes an upper cover, a lower cover, and a base plate. The base plate is horizontally positioned, the lower cover is vertically fixed to the middle of the upper surface of the base plate, and the upper cover is fixed above the lower cover.

[0015] Multiple tie rods are fixed between the two sides of the bearing housing cover and the bearing housing base plate.

[0016] A test method for a fatigue testing apparatus for flexible connecting rod couplings includes the following steps:

[0017] Step 1: Open the bearing housing cover, install the fatigue testing device, keep the connection between the connecting flange and the fixed bracket disconnected, and weld the part to be welded in place;

[0018] Step 2: Rotate the torsion disc and observe whether the fatigue testing device can rotate smoothly. If it cannot, find the cause and ensure that the fatigue testing device can rotate.

[0019] Step 3: Close the bearing housing cover, screw the set screw into the threaded hole connecting the upper and lower covers of the bearing housing, and connect the connecting flange to the fixed bracket.

[0020] Step 4: Control the servo motor to apply vertical tension, ensuring the dynamic torque T is within ±10kN·m, frequency 4Hz, and cycle 1 million times;

[0021] Step 5: After the test, observe the appearance of the flexible connecting rod coupling for any abnormalities. Disassemble the spherical and cylindrical rubber joints of the flexible connecting rod coupling and check the fatigue damage status of the rubber parts.

[0022] The beneficial effects of this invention compared to the prior art are:

[0023] This invention is used to verify the fatigue resistance of the internal spherical and cylindrical rubber joints of an elastic connecting rod coupling during the development stage. By controlling the vertical tension of the servo motor to adjust the dynamic torque input value, the vertical tension is converted into the horizontal axial force through the lever arm device and the torsion shaft disc. The advantages are that the length of the lever arm device is adjustable, the vertical tension of the servo motor is adjustable, and the operability is high. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a fatigue testing device for an elastic connecting rod coupling according to the present invention;

[0025] Figure 2 This is a schematic diagram of the working structure of the lever arm assembly in this invention;

[0026] Figure 3 This is a schematic diagram of the structure of the elastic connecting rod coupling in this invention;

[0027] Figure 4 This is a schematic diagram of the torsion shaft disk in this invention;

[0028] Figure 5 This is a schematic diagram of the bearing housing structure in this invention;

[0029] Figure 6 This is a cross-sectional structural diagram of the bearing housing in this invention. Detailed Implementation

[0030] To make the technical problems solved, the technical solutions, and the beneficial effects of the present invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0031] Specific implementation method one: Combining Figures 1 to 6 This embodiment describes a fatigue testing device for an elastic connecting rod coupling, comprising a torsion disc 1, a lever arm assembly 3, a transmission shaft 8, a fixed bracket 10, a transmission component, a servo motor, and multiple bearing seats 2. The servo motor drives the transmission component to reciprocate vertically. The lower end of the transmission component is rotatably connected to the outer end of the lever arm assembly 3, and the inner end of the lever arm assembly 3 is fixedly connected to the torsion disc 1. The torsion disc 1 is horizontally positioned via the bearing seats 2. The inner end of the torsion disc 1 is fixedly connected to the input end of the elastic connecting rod coupling 6, and the output end of the elastic connecting rod coupling 6 is fixedly connected to the inner end of the transmission shaft 8. The transmission shaft 8 is horizontally positioned via the bearing seats 2, and the outer end of the transmission shaft 8 is fixedly connected to the fixed bracket 10.

[0032] One end of the device transmits dynamic torque to the elastic connecting rod coupling 6 through the lever arm assembly 3, while the other end is fixed and constrained. The dynamic torque is absorbed by the elastic connecting rod coupling 6 itself, which has the ability to compensate for deformation. The fatigue damage status of the overall appearance of the elastic connecting rod coupling 6 and the rubber joint components is tested after a certain number of torsion cycles at a given frequency.

[0033] Since the fixed bracket 10 is stationary, after the dynamic torque is transmitted to the elastic connecting rod coupling 6, the fluctuation of the dynamic torque is absorbed by the deformation compensation of the spherical rubber joint 602 and the cylindrical rubber joint 603 inside the elastic connecting rod coupling 6.

[0034] The length of lever arm assembly 3 is L, and the vertical force F applied by the servo motor is F=T / L, where T is the dynamic torque.

[0035] The elastic link coupling 6 includes an input flange 601, an output flange 605, an intermediate shaft 604, and two elastic link assemblies. The two elastic link assemblies are arranged side by side, and the intermediate shaft 604 is connected between the two elastic link assemblies. The input flange 601 is connected to the elastic link assembly on the input side, and the output flange 605 is connected to the elastic link assembly on the output side. The elastic link assembly includes a ball-shaped rubber joint 602 and a cylindrical rubber joint 603.

[0036] Specific Implementation Method Two: Combining Figure 2This embodiment describes a transmission assembly that includes a first pull rod 11, a second pull rod 13, and a third pull rod 14. The upper end of the first pull rod 11 is connected to the output end of the servo motor. The lower end of the first pull rod 11 is fixedly connected to the upper end of the second pull rod 13 via a first fastener 12. The middle part of the third pull rod 14 is horizontally inserted into the lower end of the second pull rod 13 and is rotatably connected to the second pull rod 13. The two ends of the third pull rod 14 are respectively fixedly connected to the outer ends of the lever arm assembly 3 via second fasteners 16.

[0037] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment 1.

[0038] During the process of the servo motor transmitting dynamic torque to the lever arm assembly 3, the first fastener 12 and the second fastener 16 are tightly fitted with threaded connections to avoid inaccurate dynamic torque transmission due to gaps.

[0039] Specific implementation method three: Combining Figure 2 In this embodiment, the middle part of the third pull rod 14 is rotatably connected to the second pull rod 13 via a rolling bearing 15.

[0040] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment Two.

[0041] The inner hole of the rolling bearing 15 installed inside the second tie rod 13 passes through the third tie rod 14, which can ensure the smooth rotation of the lever arm assembly 3 when the second tie rod 13 moves in the vertical direction.

[0042] Specific implementation method four: Combination Figures 1 to 2 In this embodiment, the inner end of the lever arm assembly 3 is fixedly connected to the torsion shaft disk 1 by a third fastener 4.

[0043] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment 1.

[0044] The torsion disc 1 is connected to the lever arm assembly 3 via the third fastener 4, transmitting dynamic torque to the horizontal shaft system and then to the elastic connecting rod coupling 6.

[0045] Specific Implementation Method Five: Combining Figure 4 This embodiment describes a torsion shaft disk 1 including a torsion disk 101 and a torsion shaft 103. The torsion shaft 103 is horizontally arranged, and the torsion disk 101 is fixed to the outer end of the torsion shaft 103. A through hole 104 is provided on the side wall of the torsion shaft 103, and the end of the third fastener 4 is inserted into the through hole 104.

[0046] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment Four.

[0047] Specific Implementation Method Six: Combination Figure 4In this embodiment, a plurality of reinforcing ribs 102 are evenly distributed and fixed between the torsion disc 101 and the torsion shaft 103 along the circumferential direction.

[0048] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment Five.

[0049] Specific implementation method seven: Combination Figure 1 and Figure 4 In this embodiment, the inner end of the torsion shaft 103 is fixedly connected to the input flange 601 of the elastic connecting rod coupling 6 via the input side flange 5, the inner end of the transmission shaft 8 is fixedly connected to the output flange 605 of the elastic connecting rod coupling 6 via the output side flange 7, and the outer end of the transmission shaft 8 is fixedly connected to the fixed bracket 10 via the connecting flange 9.

[0050] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment Five.

[0051] The input side flange 5 is welded to the torsion shaft 1, and the output side flange 7 and the connecting flange 9 are also welded to the drive shaft 8.

[0052] The connecting flange 9 and the fixed bracket 10 are connected by fasteners for a tight fit, and remain stationary during fatigue testing.

[0053] Specific implementation method eight: Combination Figures 5 to 6 This embodiment describes the bearing housing 2, which includes an upper bearing housing cover 201, a lower bearing housing cover 202, and a base plate 204. The base plate 204 is horizontally arranged, the lower bearing housing cover 202 is vertically fixed to the middle of the upper surface of the base plate 204, and the upper bearing housing cover 201 is fixed above the lower bearing housing cover 202.

[0054] The undisclosed technical features in this embodiment are the same as those in Specific Embodiment 1.

[0055] To ensure detachability after welding, the bearing housing 2 is designed as a separate type with an upper cover 201 and a lower cover 202.

[0056] There are three bearing housings 2, which are respectively located at both ends of the torsion shaft 103 and in the middle of the transmission shaft 8.

[0057] Specific Implementation Method Nine: Combining Figure 5 In this embodiment, multiple tie rods 203 are fixedly connected between the two sides of the bearing housing lower cover 202 and the bearing housing base plate 204.

[0058] The undisclosed technical features in this embodiment are the same as those in specific embodiment eight.

[0059] The upper end face of the bearing housing lower cover 202 is symmetrically provided with threaded holes 205 for connecting the upper and lower covers of the bearing housing. The upper end face of the bearing housing upper cover 201 is provided with set screws on both sides, and the ends of the set screws are threaded to the threaded holes 205 for connecting the upper and lower covers of the bearing housing. The lower end face of the bearing housing lower cover 202 is symmetrically provided with multiple threaded holes 206 for connecting the lower cover and the base plate. The lower end face of the bearing housing base plate 204 is symmetrically provided with multiple connecting screws, and the ends of the connecting screws are threaded to the threaded holes 206 for connecting the lower cover and the base plate of the bearing housing.

[0060] Specific Implementation Method Ten: Combining Figures 1 to 6 This embodiment describes a test method for a fatigue testing device for an elastic connecting rod coupling, comprising the following steps:

[0061] Step 1: Open the bearing housing cover 201, install the fatigue testing device, keep the connection between the connecting flange 9 and the fixed bracket 10 disconnected, and weld the part to be welded.

[0062] Step 2: Rotate the torsion disc 1 and observe whether the fatigue testing device can rotate smoothly. If it cannot, find the cause and ensure that the fatigue testing device can rotate.

[0063] Step 3: Close the upper cover 201 of the bearing housing, screw the set screw into the threaded hole 205 at the connection of the upper and lower covers of the bearing housing, and connect the connecting flange 9 to the fixed bracket 10.

[0064] Step 4: Control the servo motor to apply vertical tension, ensuring the dynamic torque T is within ±10kN·m, frequency 4Hz, and cycle 1 million times;

[0065] Step 5: After the test, observe whether there are any abnormalities in the appearance of the elastic connecting rod coupling 6. Disassemble the spherical rubber joint 602 and the cylindrical rubber joint 603 of the elastic connecting rod coupling 6 to check the fatigue damage status of the rubber parts.

[0066] Working principle

[0067] Dynamic torque is simulated by the reciprocating motion of the first pull rod 11 in the vertical direction driven by the servo motor. The first pull rod 11 drives the second pull rod 13 through the first fastener 12. The inner hole of the rolling bearing 15 installed inside the second pull rod 13 passes through the third pull rod 14. The third pull rod 14 is fixed to the lever arm assembly 3 through the second fastener 16. The lever arm assembly 3 passes through the through hole 104 on the torsion shaft disk 1 through the third fastener 4, so as to realize the dynamic torque transmission to the torsion shaft disk 1. The torsion shaft 1 is connected to the input side flange 5 by welding. The drive shaft 8 is also connected to the output side flange 7 and the connecting flange 9 by welding. The connecting flange 9 is connected to the fixed bracket 10 by fasteners. The final dynamic torque transmission path is servo motor → lever arm assembly 3 → torsion shaft 1 → input side flange 5 → elastic connecting rod coupling 6 → output side flange 7 → drive shaft 8 → connecting flange 9 → fixed bracket 10. The spherical rubber tube connector 602 and the cylindrical rubber joint 603 of the elastic connecting rod coupling 6 absorb dynamic torque fluctuations. Finally, the fatigue performance of the elastic connecting rod coupling 6 is judged by inspecting the overall appearance of the machine and the fatigue damage of the rubber joint.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A fatigue testing device for elastic connecting rod couplings, characterized in that: It includes a torsion shaft disk (1), a lever arm assembly (3), a transmission shaft (8), a fixed bracket (10), a transmission component, a servo motor, and multiple bearing seats (2). The servo motor drives the transmission component to reciprocate in the vertical direction. The lower end of the transmission component is rotatably connected to the outer end of the lever arm assembly (3). The inner end of the lever arm assembly (3) is fixedly connected to the torsion shaft disk (1). The torsion shaft disk (1) is horizontally set through the bearing seats (2). The inner end of the torsion shaft disk (1) is fixedly connected to the input end of the elastic connecting rod coupling (6). The output end of the elastic connecting rod coupling (6) is fixedly connected to the inner end of the transmission shaft (8). The transmission shaft (8) is horizontally set through the bearing seats (2). The outer end of the transmission shaft (8) is fixedly connected to the fixed bracket (10).

2. The fatigue testing device for elastic connecting rod couplings according to claim 1, characterized in that: The transmission assembly includes a first pull rod (11), a second pull rod (13) and a third pull rod (14). The upper end of the first pull rod (11) is connected to the output end of the servo motor. The lower end of the first pull rod (11) is fixed to the upper end of the second pull rod (13) through a first fastener (12). The middle part of the third pull rod (14) is horizontally inserted into the lower end of the second pull rod (13) and is rotatably connected to the second pull rod (13). The two ends of the third connecting rod (14) are fixed to the outer ends of the lever arm assembly (3) through second fasteners (16).

3. The fatigue testing device for an elastic connecting rod coupling according to claim 2, characterized in that: The middle part of the third tie rod (14) is rotatably connected to the second tie rod (13) by a rolling bearing (15).

4. The fatigue testing device for an elastic connecting rod coupling according to claim 1, characterized in that: The inner end of the lever arm assembly (3) is fixed to the torsion shaft disk (1) by a third fastener (4).

5. A fatigue testing device for an elastic connecting rod coupling according to claim 4, characterized in that: The torsion shaft disc (1) includes a torsion disc (101) and a torsion shaft (103). The torsion shaft (103) is horizontally arranged, and the torsion disc (101) is fixed to the outer end of the torsion shaft (103). A through hole (104) is provided on the side wall of the torsion shaft (103), and the end of the third fastener (4) is inserted into the through hole (104).

6. A fatigue testing device for an elastic connecting rod coupling according to claim 5, characterized in that: Multiple reinforcing ribs (102) are evenly distributed and fixed between the torsion disc (101) and the torsion shaft (103) along the circumferential direction.

7. A fatigue testing device for an elastic connecting rod coupling according to claim 5, characterized in that: The inner end of the torsion shaft (103) is fixed to the input flange (601) of the elastic connecting rod coupling (6) via the input side flange (5), the inner end of the drive shaft (8) is fixed to the output flange (605) of the elastic connecting rod coupling (6) via the output side flange (7), and the outer end of the drive shaft (8) is fixed to the fixed bracket (10) via the connecting flange (9).

8. A fatigue testing device for an elastic connecting rod coupling according to claim 1, characterized in that: The bearing housing (2) includes a bearing housing upper cover (201), a bearing housing lower cover (202) and a bearing housing base plate (204). The bearing housing base plate (204) is horizontally arranged, the bearing housing lower cover (202) is vertically fixed to the middle of the upper end face of the bearing housing base plate (204), and the bearing housing upper cover (201) is fixed above the bearing housing lower cover (202).

9. A fatigue testing device for an elastic connecting rod coupling according to claim 8, characterized in that: Multiple tie rods (203) are fixed between the two sides of the bearing housing lower cover (202) and the bearing housing base plate (204).

10. A test method for a fatigue testing apparatus for an elastic connecting rod coupling according to any one of claims 1 to 9, characterized in that: Includes the following steps: Step 1: Open the bearing housing cover (201), install the fatigue testing device, keep the connection between the connecting flange (9) and the fixed bracket (10) disconnected, and weld the part to be welded. Step 2: Rotate the torsion disc (1) and observe whether the fatigue testing device can rotate smoothly. If it cannot, find the cause and ensure that the fatigue testing device can rotate. Step 3: Close the bearing housing cover (201), screw in the set screw at the threaded hole (205) connecting the upper and lower covers of the bearing housing, and connect the connecting flange (9) with the fixed bracket (10); Step 4: Control the servo motor to apply vertical tension, ensuring the dynamic torque T is within ±10kN·m, frequency 4Hz, and cycle 1 million times; Step 5: After the test, observe whether there are any abnormalities in the appearance of the elastic connecting rod coupling (6), disassemble the ball-shaped rubber joint (602) and the cylindrical rubber joint (603) of the elastic connecting rod coupling (6), and check the fatigue damage status of the rubber parts.

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