A device and method for testing the stiffness of a rail vehicle elastic joint

Abstract

A method for testing the stiffness of elastic joints in railway vehicles involves first applying an axial force to the outer surface of the elastic joint, reducing the elastic clearance to zero and ensuring the outer surface of the elastic joint is in contact and maintained. Then, forces are applied radially to the outer surface and axially along the axial mandrel to detect the axial and radial stiffness of the elastic joint. Applying an axial force to the outer surface first, reducing the elastic clearance to zero, effectively applies a preload to the elastic joint, eliminating the influence of clearance on the stiffness test results in subsequent axial and radial stiffness tests, making the test results more closely reflect actual operating conditions.

Description

Technical Field

[0001] This invention relates to the field of testing and inspection of elastic joints in rail vehicles, specifically to a testing device and method for the stiffness of elastic joints in rail vehicles. Background Technology

[0002] Elastic joints are among the most widely used elastic elements on rail vehicles. Mostly composed of rubber-metal composites, they possess numerous advantages, including excellent omnidirectional movement, design versatility, adjustable elastic parameters, impact resistance, ability to attenuate and absorb high-frequency vibrations and noise, and lightweight construction. In rail vehicles, they play a crucial role in transferring loads, buffering instantaneous impacts, attenuating and absorbing harmful vibrations, and ensuring the smooth and stable operation of trains at high speeds. Elastic joints are installed in pairs within the bogies, with each car requiring 8 pairs (16 pieces) of elastic joints (4 pairs per bogie). To ensure the smooth and safe operation of the vehicle, the stiffness of the 8 pairs of elastic joints installed together must be within the same range. Therefore, the joints must undergo stiffness testing before leaving the factory for selection.

[0003] like Figure 1 As shown, this is a mandrel-type elastic joint S. A vulcanized rubber layer S4 exists between the mandrel S3 and the outermost outer sheath S4. The outer sheath S4 is divided into two discontinuous upper and lower parts with a gap S2 between them. When conducting stiffness tests on this mandrel, both axial and radial stiffness tests are required. Existing technologies do not consider the impact of the gap S2 on the test results. In fact, during axial and radial stiffness tests, the presence of the gap S2 generates a certain amount of compression, especially during axial stiffness tests, where this compression significantly affects the stiffness test results. Furthermore, this elastic joint S requires pre-compression to zero the gap S before actual vehicle installation; therefore, existing technologies cannot reflect the stiffness performance under actual application conditions.

[0004] A search revealed existing technical documents concerning methods and apparatus for testing the stiffness of elastic joints. Examples include an invention patent with application number "CN202010284429.3" entitled "Mechanism and Method for Measuring the Radial Static Stiffness of a Metal-Rubber Ball Joint," and a utility model patent with application number "CN202220441529.7" entitled "Mechanism for Testing the Radial Stiffness of a Steering Gear Bearing." However, these published technical solutions do not consider the stiffness test results of the clearance S or its impact on actual working conditions; therefore, the accuracy and practicality of their stiffness tests need improvement.

[0005] Therefore, it is of great significance to propose a more accurate test device and method for the elastic node stiffness of rail vehicles that is more in line with actual working conditions. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for testing the stiffness of elastic joints in rail vehicles. First, a force along the axial direction of the elastic joint is applied to the outer surface of the elastic joint to reduce the elastic gap of the outer surface to zero, thereby making the outer surface of the elastic joint fit together and maintain its position. Then, forces are applied to the outer surface of the elastic joint radially and along the axial direction of the elastic joint along the axial mandrel, respectively, to detect the axial and radial stiffness of the elastic joint.

[0007] Furthermore, applying a force along the axial direction to the outer surface of the elastic node is applying a downward pressure along the axial direction to the end face of the outer surface.

[0008] Alternatively, the force applied to the outer surface of the elastic node along the axial direction of the elastic node can be a frictional force applied to the circumferential surface of the outer surface along the axial direction of the elastic node.

[0009] Furthermore, a metal jacket is provided that is interference-fitted with the circumference of the outer jacket surface. The elastic node is pressed into the metal jacket, and the frictional force of the interference fit between the outer jacket surface and the metal jacket is used to reduce the elastic gap of the outer jacket surface to zero.

[0010] The aforementioned application of force along the radial direction of the elastic node to the outer surface of the elastic node is to simultaneously apply a consistent downward vertical force to the outer surface after the elastic gap is reduced to zero, and at the same time provide constant upward vertical support to the core of the elastic node.

[0011] A test device for the stiffness of elastic nodes in rail vehicles is also proposed, comprising a cover plate and a metal jacket, both of which are hollow cylinders. The elastic node can be placed inside the metal jacket, with a small clearance fit between the inner surfaces of the metal jacket and the hollow cylinder. After the elastic node is placed inside the metal jacket, the end face of the jacket protrudes beyond the end face of the metal jacket. After the cover plate is closed on the metal jacket, one end of the mandrel of the elastic node extends from the center of the cover plate, and the other end extends from the center of the metal jacket. A clamping device is also connected between the cover plate and the metal jacket. After the cover plate is closed on the metal jacket, the clamping device can press the cover plate against the end face of the elastic node's jacket, providing a clamping force along the axial direction of the elastic node and locking it in place.

[0012] Furthermore, the clamping device is a latch, which includes a buckle and a wrench; the edge of the cover plate is fixedly connected to a lug, the side circumference of the metal jacket is fixedly connected to a wrench seat, and one end of the wrench is hinged to the wrench seat; the buckle is hinged to the wrench via a pin, and the buckle is vertically connected to the pin.

[0013] Furthermore, the buckle and the pin are connected by a thread.

[0014] Furthermore, one end of the metal jacket protrudes inward to form a boss surface, which can support the end face of the jacket surface of the elastic node.

[0015] Furthermore, a groove is formed on the side circumference of the metal jacket, and the wrench seat is fixedly connected to the bottom of the groove; a second groove is formed on the edge of the cover plate, and the buckle and the hanging ear are accommodated in the second groove when connected.

[0016] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0017] 1: First, apply a force along the axial direction of the elastic node to the outer surface of the elastic node. After the elastic gap of the outer surface is reduced to zero, it is equivalent to applying a pre-stress to the elastic node under test. This eliminates the influence of the gap on the stiffness test results in the subsequent axial and radial stiffness tests of the elastic node, making the test results closer to the actual working conditions. Attached Figure Description

[0018] Figure 1 Schematic diagram of a spindle-type elastic node structure;

[0019] Figure 2 : Front view of the experimental apparatus structure in Example 3;

[0020] Figure 3 Top view of the experimental apparatus structure in Example 3;

[0021] Figure 4 : Force application state diagram for radial stiffness test of elastic node. Detailed Implementation

[0022] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Example 1: Apply a frictional force along the axial direction of the elastic node to the circumferential surface of the outer casing to reduce the elastic gap S2 of the outer casing to zero.

[0024] In this embodiment, a frictional force along the axial direction of the elastic node is first applied to the circumferential surface of the outer sleeve, causing the upper and lower split parts of the outer sleeve S1 of the elastic node to fit together completely, thus reducing the elastic gap S2 between them to zero. Maintaining this frictional force and the zero elastic gap S2 is equivalent to applying a preload to the elastic node.

[0025] After applying preload, a force is applied to the outer sleeve surface S1 of the elastic node and a force is applied to the mandrel S3 along the axial direction of the elastic node to detect the axial and radial stiffness of the elastic node. The specific process of applying pressure to detect stiffness is already known in existing technology and will not be elaborated here. This embodiment focuses on detecting static stiffness. Taking axial stiffness as an example, a fixed force is applied to the mandrel S3 and the axial deformation of the mandrel S3 is detected to obtain the axial static stiffness.

[0026] The aforementioned frictional force can be provided by fitting a metal jacket onto the outer periphery of the outer jacket surface S1, pressing the elastic node into the metal jacket, and using the frictional force of the interference fit between the outer jacket surface S1 and the metal jacket to reduce the elastic gap S2 of the outer jacket surface S1 to zero.

[0027] Example 2: Applying downward pressure along the axial direction of the elastic node to the end face of the outer casing S1 causes the elastic gap S2 of the outer casing to return to zero.

[0028] Unlike Example 1, which applied a frictional force along the axial direction of the elastic node to the circumferential surface of the outer sleeve S1, this example directly applies a downward pressure along the axial direction of the elastic node to the end face of the outer sleeve S1. Under this downward pressure, the upper and lower split parts of the outer sleeve S1 come together, and the elastic gap S2 returns to zero. The subsequent stiffness test process for the elastic node is the same as in Example 1.

[0029] After the elastic gap S2 of the outer sleeve surface S1 is reduced to zero, during the radial stiffness test, it is preferable to simultaneously apply a consistent downward vertical force to the outer sleeve surface S1 after the elastic gap S2 is reduced to zero, and simultaneously provide constant upward vertical support to the mandrel S3 of the elastic node. Specifically, as follows... Figure 4 As shown, an external support component (not shown in the diagram) can be used, with mandrels S3 at both ends supporting the external support. Since the elastic gap S2 returns to zero, this is to ensure the upper and lower surfaces of the outer sleeve S1 are aligned correctly. Figure 4 The left and right split parts receive the same vertical downward force. It is necessary to apply the same force to the split parts of the outer casing S1 at the same time to further ensure that the radial deformation of the entire outer casing S1 is consistent when the radial stiffness is applied, so as to accurately measure the radial stiffness.

[0030] As shown in the table below, a comparison between the existing elastic node stiffness test and the stiffness test conducted after first setting the elastic gap S2 to zero in the above embodiments shows that the stiffness data of Embodiments 1 and 2 are more accurate and closer to the actual working conditions.

[0031]

[0032] Example 3: A device for applying downward pressure along the axial direction of the elastic node to the end face of the outer sleeve surface S1.

[0033] like Figure 2-4As shown, the device is designed in two parts: a cover plate 1 and a metal jacket 2. Both the cover plate 1 and the metal jacket 2 are hollow cylinders. The elastic node can be placed inside the metal jacket 2, and the inner surfaces of the metal jacket 2 and the hollow cylinder are fitted with a small gap. After the elastic node is placed inside the metal jacket 2, the end face S11 of the jacket protrudes from the end face of the metal jacket 2. After the cover plate 1 is closed on the metal jacket 2, one end of the spindle of the elastic node extends from the center of the cover plate 1, and the other end extends from the center of the metal jacket 2. A clamping device is also connected between the cover plate 1 and the metal jacket 2. After the cover plate 1 is closed on the metal jacket 2, the clamping device can press the cover plate 1 against the end face S11 of the elastic node's jacket, providing a clamping force along the axial direction of the elastic node and locking it in place.

[0034] In a specific application of this device, combined with Embodiment 2, the elastic node is first placed inside the metal jacket 2. Since the two have a small gap fit, it can be directly placed in without pressing it in. At this point, as... Figure 4 As shown, the end face S11 of the outer jacket protrudes from the end face of the metal jacket 2. At this time, the cover plate 1 is closed, and the pressing device applies downward pressure along the axial direction of the elastic node to the protruding end face S11 of the outer jacket through the cover plate 1, so that the elastic gap S2 of the outer jacket is zero. After the pressing device is locked, it can maintain the state of zero elastic gap S2 and generate pre-pressure.

[0035] One embodiment of the clamping device involves creating a threaded hole on the end face of the metal jacket 2, and then clamping and locking the cover plate 1 together with bolts. Another embodiment utilizes a latch for clamping and locking. The latch 3 includes a latch 31 and a wrench 32; a lug 11 is fixedly connected to the edge of the cover plate 1, and a wrench seat 21 is fixedly connected to the side circumference of the metal jacket 2. One end of the wrench 32 is hinged to the wrench seat 21; the latch 31 is hinged to the wrench 32 via a pin 33, and the latch 31 is vertically connected to the pin 33. During clamping, the latch 31 is placed on the lug 11, and the wrench 32 is swung downwards towards the metal jacket 2. When the wrench 32 swings to a vertical position and contacts the metal jacket 2, the latch 3 is locked. During the aforementioned process, the cover plate 1 continuously presses down on the end face S11 of the jacket and maintains the clamping position.

[0036] To adjust the overlap distance of the latch 31 in the locking mechanism 3, the latch 31 and the pin 33 are connected by threads. After the metal sleeve 2 is inserted into the elastic nodes of different heights, the end face S11 of the sleeve protrudes from the end face of the metal sleeve 2 at different heights. The overlap distance can be adjusted by the thread between the latch 31 and the pin 33 to ensure that the cover plate 1 can be pressed and maintained by the locking mechanism 3.

[0037] like Figure 3 As shown, one end of the metal jacket 2 protrudes inward to form a boss surface 22. After the elastic node is inserted into the metal jacket 2, the end face of the jacket at one end is supported by the boss surface 22. When pressure is applied to the end face S11 of the jacket that protrudes from the other end of the metal jacket 2, the boss surface 22 provides corresponding support force.

[0038] The metal jacket 2 has a groove 23 on its side circumference, and the wrench seat 21 is fixedly connected to the bottom of the groove 23. The lug 11 has a groove 12 on the edge of the cover plate 1, and the buckle 31 is accommodated in the groove 12 when connected to the lug 11. The wrench seat 21 and the wrench in the tightened state can be accommodated in the groove 23. The end of the wrench 21 has a bent part 321 to facilitate the operation of tightening the locking buckle 3.

[0039] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for testing the stiffness of a rail vehicle elastic joint, characterized in that: Includes a cover plate (1) and a metal jacket (2), both of which are hollow cylinders; the elastic node can be placed inside the metal jacket (2) and the inner side of the metal jacket (2) and the hollow cylinder are fitted with a small gap. After the elastic node is placed inside the metal jacket (2), the end face of the elastic node protrudes from the end face of the metal jacket (2). After the cover plate (1) is closed on the metal jacket (2), one end of the spindle of the elastic node extends from the center of the cover plate (1) and the other end extends from the center of the metal jacket (2). A clamping device is also connected between the cover plate (1) and the metal jacket (2). After the cover plate (1) is closed on the metal jacket (2), the clamping device can press the cover plate (1) against the end face of the elastic node, providing a clamping force along the axial direction of the elastic node and locking it in place.

2. The testing device for elastic node stiffness of rail vehicles as described in claim 1, characterized in that: The clamping device is a latch (3), which includes a buckle (31) and a wrench (32); the edge of the cover plate (1) is fixedly connected to the lug (11), and the side of the metal jacket (2) is fixedly connected to the wrench seat (21). One end of the wrench (32) is hinged to the wrench seat (21); the buckle (31) is hinged to the wrench (32) through the pin (33), and the buckle (31) is vertically connected to the pin (33).

3. The testing device for elastic node stiffness of rail vehicles as described in claim 2, characterized in that: The buckle (31) and the pin (33) are connected by threads.

4. The testing device for elastic node stiffness of rail vehicles as described in claim 3, characterized in that: The bottom of one end of the metal jacket (2) protrudes inward to form a boss surface (22), which can support the end face of the jacket surface of the elastic node.

5. The testing device for elastic node stiffness of rail vehicles as described in claim 4, characterized in that: The metal jacket (2) has a groove (23) on its side circumference, and the wrench seat (21) is fixedly connected to the bottom of the groove (23); the hanging ear (11) has a groove (12) on the edge of the cover plate (1), and the buckle (31) and the hanging ear (11) are accommodated in the groove (12) when connected.

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