A multi-section nonlinear stiffness hourglass spring

Abstract

A multi-stage nonlinear stiffness hourglass spring comprises a conical rubber body with a central hollow vibration damping zone, and a support plate and a mounting plate arranged in parallel. The conical rubber body is vulcanized and connected between the support plate and the mounting plate. The conical rubber body has a rubber stopper in the central hollow vibration damping zone, a first vibration damping gap is formed between the side surface of the rubber stopper and the inner side surface of the conical rubber body, and a second vibration damping gap is formed between the top surface of the rubber stopper and the mounting surface where the mounting plate is located. The hourglass spring provided by the present invention has a rubber stopper provided in the central hollow vibration damping zone of the rubber body. When the hourglass spring is subjected to a large load, the inner side surface of the rubber body can contact the rubber stopper to form a section of nonlinear variable stiffness. After the rubber stopper contacts the metal part of the mounting surface where the mounting plate is located, another section of nonlinear variable stiffness can be provided, and the nonlinear stiffness variation range is large.

Description

Technical Field

[0001] The invention relates to the technical field of rail vehicle vibration damping components, in particular to a multi-section nonlinear stiffness hourglass spring. Background Art

[0002] The hourglass spring is a secondary suspension damping device for rail vehicles. Its basic structure consists of a vulcanized rubber body connected between a parallel support plate and a mounting plate. The rubber body has a symmetrically distributed cone structure, with a hollow damping zone in the middle. The loaded deformation of the rubber body provides flexible support for the vehicle, improving driving comfort and meeting stiffness requirements under varying loads. Because the damping device requires a certain degree of nonlinear stiffness to meet varying stiffness requirements under varying vehicle loads, matching nonlinear stiffness design is crucial in hourglass spring development.

[0003] A search revealed prior art documents on hourglass springs and variable stiffness designs. For example, the utility model authorization announcement document, "Hourglass Spring and Vehicle with Hourglass Spring," has publication number CN207526919U. The disclosed hourglass spring has low vertical stiffness, making it a viable alternative to the low-stiffness characteristics of coil spring steel without the risk of sudden breakage. However, its stiffness varies linearly, failing to provide nonlinear stiffness variation. This makes it unsuitable for applications with significant vehicle load fluctuations.

[0004] For example, the invention patent publication number is "CN110762149A" and the name is "A nonlinearly slowed variable stiffness hourglass spring". In the disclosed technical solution, the upper elastic body has an upper variable stiffness part for nonlinear slowing and changing stiffness, and the lower elastic body has a lower variable stiffness part for nonlinear slowing and changing stiffness; the upper elastic body also has an upper compressive expansion body, the upper variable stiffness part is an upper variable stiffness tray, and the outer periphery of the upper variable stiffness tray is an annular upper variable stiffness edge; the bottom of the upper compressive expansion body is connected to the upper variable stiffness tray inside the upper variable stiffness edge; the lower elastic body also has a lower compressive expansion body, the lower variable stiffness part is a lower variable stiffness tray, and the outer periphery of the lower variable stiffness tray is an annular lower variable stiffness edge; the bottom of the lower compressive expansion body is connected to the lower variable stiffness tray inside the lower variable stiffness edge. This comparative document shows that when the compressive expansion body is loaded and deformed, it can contact the variable stiffness tray to provide nonlinear variable stiffness. Although nonlinear stiffness change can be achieved, its change range is small. After the variable stiffness tray and the compressive expansion body come into contact, another stage of nearly linear stiffness change is presented.

[0005] For example, the invention patent publication number "CN115782946A" is titled "An Hourglass Spring for Secondary Vibration Damping." The technical solution disclosed in this reference utilizes a stopper fixed to a mounting plate to provide nonlinear stiffness variation. However, because the stopper must be assembled between a specific connecting plate and a mounting plate, the overall structure of the hourglass spring is complex and installation is cumbersome. Furthermore, because the stopper is located on the mounting plate, it produces nonlinear stiffness variation when in contact with the rubber body. While this range of stiffness variation is greater than that of the second reference, the stopper cannot come into contact with any metal parts, leaving the range of stiffness variation limited. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a multi-section nonlinear stiffness hourglass spring, comprising a conical rubber body with a hollow vibration damping zone in the middle and a support plate and a mounting plate arranged in parallel. The conical rubber body is vulcanized and connected between the support plate and the mounting plate. A rubber stopper is provided in the middle of the hollow vibration damping zone of the conical rubber body. A first vibration damping gap is formed between the side surface of the rubber stopper and the inner side surface of the conical rubber body, and a second vibration damping gap is formed between the top surface of the rubber stopper and the mounting surface where the mounting plate is located. When the first vibration damping gap is zero, it has at least a first nonlinear stiffness, and when the second vibration damping gap is zero, it has at least a second nonlinear stiffness.

[0007] Furthermore, the top surface of the rubber stopper includes a first arc surface.

[0008] Furthermore, the side surface of the rubber stopper and the inner side surface of the conical rubber body are connected via a first transition arc surface.

[0009] Furthermore, the side surface of the rubber stopper is a first inclined surface, the first inclined surface has a first inclination angle relative to the central axis of the hourglass spring, and the first inclination angle is an acute angle.

[0010] Furthermore, a second inclination angle is formed between the inner side surface of the conical rubber body and the central axis of the hourglass spring, and the second inclination angle is smaller than the first inclination angle.

[0011] Furthermore, the first inclined surface is an arc-shaped convex surface, and the inner side surface of the conical rubber body is an arc-shaped concave surface.

[0012] Furthermore, the first transition arc surface is concave to form an annular gap groove, and the annular gap groove and the first inclined surface and the inner side surface of the conical rubber body are transitioned by arc surfaces.

[0013] Furthermore, a second arc surface is provided as a transition between the first inclined surface and the first arc surface.

[0014] Furthermore, the surface of the support plate has an annular protrusion.

[0015] Furthermore, the top surface of the annular protrusion is an arc surface, the inner side surface is an inclined surface with a third inclination angle, the outer side surface of the conical rubber body has a fourth inclination angle, and the third inclination angle is smaller than the fourth inclination angle.

[0016] Compared to the prior art, the technical solution of this application offers the following advantages: The hourglass spring provided by the present invention features a rubber stopper located in the middle of the internal, hollow vibration damping zone of the rubber body. When the hourglass spring is subjected to a significant load, the inner surface of the rubber body contacts the rubber stopper, creating a nonlinear variable stiffness. Once the rubber stopper contacts the metal mounting surface of the mounting plate, another nonlinear variable stiffness is achieved. This wide range of nonlinear stiffness variation addresses the limited nonlinear stiffness variation found in prior art. Furthermore, the hourglass spring exhibits excellent structural integrity, lacks redundant assembly features, and is easy to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Schematic diagram of the hourglass spring structure provided in Example 1 and Example 3;

[0018] Figure 2 : Figure 1 Partial enlarged view;

[0019] Figure 3 : Partial structural principle of the hourglass spring rubber body and rubber stopper provided in Example 2 Figure 1 ;

[0020] Figure 4 : Partial structural principle of the hourglass spring rubber body and rubber stopper provided in Example 2 Figure 2 . DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] like Figure 1 and Figure 2A multi-stage nonlinear stiffness hourglass spring comprises a conical rubber body 1 with a central air-displacement damping zone, and a support plate 2 and a mounting plate 3 arranged in parallel. The conical rubber body 1 is vulcanized and connected between the support plate 2 and the mounting plate 3. A rubber stopper 4 is provided in the central portion of the air-displacement damping zone of the conical rubber body 1. A first damping gap S1 is formed between the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1, and a second damping gap S2 is formed between the top surface of the rubber stopper 4 and the mounting surface of the mounting plate 3. When the first damping gap S1 is zero, the spring exhibits at least a first nonlinear stiffness, and when the second damping gap S2 is zero, the spring exhibits at least a second nonlinear stiffness.

[0023] Generally speaking, an hourglass spring has a vertically symmetrical structure, with mounting plates 3 positioned vertically on either side of a support plate 2. A conical rubber body 1 is vulcanized and connected symmetrically between the mounting plates 3 and the support plates 2. The rubber stopper 4 of the hourglass spring provided by the present invention is positioned in the middle of the radially damping zone of the conical rubber body 1, forming an integral part of the entire conical rubber body 1. This eliminates the need for separate assembly structures for the entire hourglass spring; the conical rubber body 1, mounting plate 3, and support plate 2 are vulcanized and connected to form a single unit, facilitating installation and use in a vehicle's secondary suspension.

[0024] When the hourglass spring is loaded, at light loads, the conical rubber body 1 begins to deform and compress, providing a relatively linear stiffness. As the load gradually increases, the conical rubber body 1 deforms further, and its inner surface begins to approach the side of the rubber stopper 4. When the first damping gap S1 reaches zero, i.e., the inner surface of the conical rubber body 1 and the side of the rubber stopper 4 contact each other, the rubber stopper 4, being a solid rubber with no free space, experiences greater stiffness. At this point, the hourglass spring begins to exhibit a significant nonlinear stiffness variation. During this period of continued contact between the inner surface of the conical rubber body 1 and the side of the rubber stopper 4, the hourglass spring begins to develop a second, nearly linear stiffness. When subjected to a higher load, the distance between the rubber stopper 4 and the mounting surface of the mounting plate 3 gradually decreases. When the second damping gap S2 reaches zero, the top surface of the rubber stopper 4 begins to contact the mounting surface of the mounting plate 3, providing the hourglass spring with another significant nonlinear variable stiffness. It should be noted that the mounting surface of the mounting plate 3 is not necessarily the mounting plate 3 itself. In this embodiment, the mounting plate 3 is a ring-shaped mounting plate with a central opening. However, in actual installation and use, the mounting plate 3 is mounted on a metal mounting surface. When the aforementioned high load occurs, the top surface of the rubber stopper 4 contacts the metal mounting surface, providing a significant nonlinear and large stiffness. Therefore, when the first damping gap S1 and the second damping gap S2 are zero, the hourglass spring exhibits two significant nonlinear stiffness variations. The stiffness when the second damping gap S2 is zero is significantly greater than the stiffness when the first damping gap S1 is zero. This solves the problem of insufficient nonlinear stiffness variation in the prior art. Combined with the nearly linear stiffness of the conical rubber body 1 itself due to its deformation, the hourglass spring provided by the present invention has multi-stage nonlinear variable stiffness properties, and can be applied to application conditions requiring a larger amplitude or richer variable stiffness.

[0025] The following describes the embodiments of the present invention in detail.

[0026] Example 1: Figure 1 and Figure 2 shown.

[0027] The top surface of the rubber stopper 4 preferably includes a first arcuate surface 41. In this embodiment, the rubber stopper 4 can be a partially spherical protrusion. This allows for a gradual fit after the top surface of the rubber stopper 4 contacts the mounting surface of the mounting plate 3 when a significant load is applied, providing a greater degree of variable stiffness. The spherical protrusion of the rubber stopper 4 prevents excessive stress concentration during the aforementioned contact process, positively impacting its fatigue performance. Furthermore, after the first damping gap S1 reaches zero, the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1 also gradually fit together, resulting in a more linear stiffness change during this stage.

[0028] In the above embodiment, the rubber stopper 4 and the inner surface of the conical rubber body 1 are subject to continuous compression and deformation due to load changes, resulting in a certain amount of stress concentration at the connection between the two. Over time, this area may crack and damage. To address this problem, the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1 are connected by a first transition arc surface 11 to minimize stress concentration.

[0029] Example 2: Figure 3 and Figure 4 shown.

[0030] In the above embodiment, although the connection between the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1 via the first transition arc surface 11 can alleviate stress concentration to a certain extent, since the rubber stopper 4 is an overall spherical protrusion, if the diameter of the first transition arc surface 11 is too large, the first vibration damping gap S1 will be too large. As a result, when load occurs, the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1 will not be able to contact and fit. Therefore, based on this, the rubber stopper 4 of this embodiment adopts a more preferred design.

[0031] The side surface of the rubber stopper 4 is a first inclined surface 42, which has an acute first angle α relative to the central axis of the hourglass spring. This design results in the rubber stopper 4 having a roughly trapezoidal shape. The second vibration-damping gap S2 formed between the first inclined surface 42 and the inner surface of the conical rubber body 1 is smaller than in the first embodiment. It is understood that when load is applied, the inner surface of the conical rubber body 1 will contact the side surface of the rubber stopper 4 earlier, providing nonlinear variable stiffness.

[0032] Furthermore, the inner side of the conical rubber body 1 is an arcuate concave surface 43. While the inner side of the conical rubber body 1 of an hourglass spring in prior art is often convex, the arcuate concave surface 43 is more preferably designed in this embodiment. Because the rubber stopper 4 is generally spherical and convex, a convex inner side of the conical rubber body 1 would deform under load, resulting in excessive stiffness. This would make it difficult for the rubber stopper 4 to contact the mounting surface of the mounting plate 3, thus affecting the final stiffness adjustment effect.

[0033] Furthermore, the first transition arc surface 11 is concave to form an annular gap groove 44. This annular gap groove 44 transitions to the first inclined surface 42 and the inner surface of the conical rubber body 1 through an arc-shaped surface. The design of the annular gap groove 44 creates a concave, hollow area at the junction between the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1. During extrusion deformation, the presence of the annular gap groove 44 significantly reduces the direct stress between the two, improving fatigue performance in this section. The presence of the first inclined surface 42 also does not affect the contact between the side surface of the rubber stopper 4 and the inner surface of the conical rubber body 1. This design of the annular gap groove 44 provides superior stress relief to the first transition arc surface 11 in the first embodiment. Preferably, the annular gap groove 44 can be designed as a teardrop-shaped surface, with a larger spacing at the bottom and a smaller spacing at the opening. This way, under load, the opening of the annular gap groove 44 will fit in contact and gradually transition into the groove interior, while a hollow area at the bottom provides stress relief.

[0034] Furthermore, a second inclination angle β is defined between the inner side of the conical rubber body 1 and the central axis of the hourglass spring. This second inclination angle β is smaller than the first inclination angle α. This design creates a progressive profile between the inner side of the conical rubber body 1 and the first inclined surface 42. When load is applied, when the second damping gap S2 is zero, the inner side of the conical rubber body 1 and the first inclined surface 42 gradually align, with a larger aligning area and length than in the first embodiment, resulting in a more linear stiffness change during this stage.

[0035] Furthermore, the first inclined surface 42 and the first arc surface 41 are transitioned to each other via the second arc surface 45, so that when the side surface of the rubber stopper 4 and the inner side surface of the conical rubber body 1 are in contact with each other, there is a smooth transition and the stiffness change is more linear.

[0036] Example 3: Figure 1 shown.

[0037] Based on the above embodiment, the support plate 2 is further optimized to provide a richer range of variable stiffness performance. The support plate 2 has an annular protrusion 5 on its surface. The annular protrusion 5 can be a metal protrusion, a vulcanized rubber layer on top of the metal protrusion, or a fully rubber structure. When the conical rubber body 1 deforms under load, its outer surface can contact the annular protrusion 5 when the load reaches a certain level, thereby providing another nonlinear stiffness variation.

[0038] Furthermore, the top surface of the annular protrusion 5 is an arc-shaped surface, while the inner side surface is an inclined surface with a third inclination angle γ. The outer side surface of the conical rubber body 1 has a fourth inclination angle δ, where the third inclination angle γ is smaller than the fourth inclination angle δ. With this design, the inner side surface of the annular protrusion 5 and the outer side surface of the conical rubber body 1 also form a progressive profile, meaning that the outer side surface of the conical rubber body 1 gradually conforms to the inner side surface of the annular protrusion 5. This provides a more linear stiffness change during this phase, and also ensures more uniform force on the outer side surface of the conical rubber body 1 after contact, improving its fatigue resistance.

[0039] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

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

Claims

1. A multi-section nonlinear stiffness hourglass spring, comprising a conical rubber body (1) with a hollow vibration damping zone in the middle, and a support plate (2) and a mounting plate (3) arranged in parallel, wherein the conical rubber body (1) is vulcanized and connected between the support plate (2) and the mounting plate (3), and is characterized in that: The conical rubber body (1) has a rubber stopper (4) in the middle of the idle vibration damping area, a first vibration damping gap (S1) is formed between the side surface of the rubber stopper (4) and the inner side surface of the conical rubber body (1), and a second vibration damping gap (S2) is formed between the top surface of the rubber stopper (4) and the mounting surface where the mounting plate (3) is located, and when the first vibration damping gap (S1) is zero, there is at least a first nonlinear stiffness, and when the second vibration damping gap (S2) is zero, there is at least a second nonlinear stiffness; The side surface of the rubber stopper (4) is a first inclined surface (42), and the first inclined surface (42) has a first inclination angle (α) relative to the central axis of the hourglass spring, and the first inclination angle (α) is an acute angle; the inner side surface of the conical rubber body (1) and the central axis of the hourglass spring have a second inclination angle (β), and the second inclination angle (β) is smaller than the first inclination angle (α).

2. The multi-section nonlinear stiffness hourglass spring according to claim 1, characterized in that: The top surface of the rubber stopper (4) includes a first arc surface (41).

3. The multi-section nonlinear stiffness hourglass spring according to claim 2, characterized in that: The side surface of the rubber stopper (4) and the inner side surface of the conical rubber body (1) are connected via a first transition arc surface (11).

4. The multi-section nonlinear stiffness hourglass spring according to claim 3, characterized in that: The first inclined surface (42) is an arc-shaped convex surface, and the inner side surface of the conical rubber body (1) is an arc-shaped concave surface (43).

5. The multi-section nonlinear stiffness hourglass spring according to claim 3, characterized in that: The first transition arc surface (11) is concave to form an annular gap groove (44), and the annular gap groove (44) and the first inclined surface (42) and the inner side surface of the conical rubber body (1) are all transitioned by arc surfaces.

6. The multi-section nonlinear stiffness hourglass spring according to any one of claims 3 to 5, characterized in that: A second arc surface (45) transitions between the first inclined surface (42) and the first arc surface (41).

7. The multi-section nonlinear stiffness hourglass spring according to any one of claims 1 to 5, characterized in that: The surface of the support plate (2) is provided with an annular protrusion (5).

8. The multi-section nonlinear stiffness hourglass spring according to claim 7, characterized in that: The top surface of the annular protrusion (5) is an arc surface, the inner side surface is an inclined surface with a third inclination angle (γ), the outer side surface of the conical rubber body (1) has a fourth inclination angle (δ), and the third inclination angle (γ) is smaller than the fourth inclination angle (δ).

Images