A method for realizing strain design of a conical spring rubber layer in a limited space

Abstract

The application discloses a kind of strain design method of realizing conical spring rubber layer in limited space, which is in the case where the outer diameter of outer sleeve is fixed, the radial width of annular end is extended towards the central axis of conical spring to ensure the machining of end screw hole, and then the gap between the inner periphery of outer sleeve and the outermost layer of spacer sleeve is increased to realize the equal strain design of multiple rubber bodies between outer sleeve, mandrel and multiple spacer sleeves after vulcanization forming.The design method of the application can ensure that the annular end of the outer sleeve of the conical spring has enough space for machining end screw hole in limited space, and ensure that each rubber body realizes equal strain state when the product is under pressure, so that the conical spring can avoid frequent cracks and damage of rubber body during use, avoid premature failure of rubber body, thereby improving the service life and performance of the product.

Description

Technical Field

[0001] This invention relates to a design method for a conical spring, and more particularly to a design method for achieving equal strain in the rubber layer of a conical spring within a limited space, belonging to the field of vibration reduction technology for rubber elastic elements. Background Technology

[0002] A conical spring is a rubber elastic positioning and support element suitable for various subway and light rail vehicles both domestically and internationally. Primarily used in vehicle suspension systems, it provides elastic positioning, shock absorption, and cushioning, while also eliminating high-frequency vibrations and improving vibration performance, thus ensuring vehicle safety and comfort. Conical springs are often installed as primary springs between the frame and bogie, mainly serving as elastic supports and load transfer mechanisms. They are a core component of the rail vehicle suspension system, and their performance directly affects the vehicle's motion stability.

[0003] like Figure 1 As shown, an existing conical spring includes an outer sleeve 1, a spindle 2, and multiple spacers 3 located between the outer sleeve 1 and the spindle 2. The outer sleeve 1, spindle 2, and multiple spacers 3 are made of metal and are bonded together by multiple rubber bodies 4 through vulcanization. For ease of subsequent description, the large end of the conical spring is defined as the upper end, and the small end of the conical spring is defined as the lower end. The spacers 3 are set as conical spacers. In the axial section of the conical spring, the angle between the inclined line of the conical spacer 3 located on one side of the central axis L of the conical spring and the central axis L of the conical spring is set as θ1. Then, θ1 is equal for each spacer 3. The inner circumferential surface of the outer sleeve 1 is also set as conical. The angle between the inclined line of the inner circumferential surface of the outer sleeve 1 located on one side of the central axis L of the conical spring and the central axis L of the conical spring is set as θ2. Then, θ1 = θ2. At the large end of the conical spring, an end screw hole 5 is also provided on one end of the outer sleeve 1, which is an annular end 111.

[0004] One of the problems with the existing technology is that after a period of operation, the rubber body always develops defects such as cracks and damage, causing rubber failure, which in turn affects the service life and performance of the product.

[0005] Chinese invention patent application CN111946762A, published on November 7, 2020, discloses a conical rubber spring with fire-resistant function. The conical rubber spring includes a main conical rubber body, a fire-resistant rubber layer, and an insulating layer. The insulating layer is located between the main conical rubber body and the fire-resistant rubber layer. The main conical rubber body, the insulating layer, and the fire-resistant rubber layer are formed into an integral structure by vulcanization.

[0006] The conical rubber springs disclosed in the aforementioned patent documents suffer from the aforementioned technical problems.

[0007] In summary, how to propose a design method for conical springs that can minimize defects such as cracks and damage to the rubber body during use, prevent premature failure of the rubber body, and thus improve the service life and performance of the product is an urgent technical problem that needs to be solved. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the deficiencies in the existing technology by providing a method for designing equal strain in the rubber layer of a conical spring within a limited space. This method can prevent defects such as cracks and damage to the rubber body during the use of the conical spring, thus avoiding premature failure of the rubber body and improving the service life and performance of the product.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for achieving constant strain design of the rubber layer of a conical spring in a limited space. The conical spring includes an outer sleeve, a mandrel, and multiple spacers located between the outer sleeve and the mandrel. The outer sleeve, mandrel, and multiple spacers are bonded together by multiple rubber bodies through vulcanization. The inner circumferential surface of the outer sleeve and the spacers are both set in a conical shape. An end screw hole is also opened on one end of the annular end of the outer sleeve. The method for achieving constant strain design of the rubber layer of the conical spring in a limited space is to extend the radial width of the annular end toward the central axis of the conical spring while keeping the outer diameter of the outer sleeve constant to ensure the processing of the end screw hole. Then, by increasing the gap between the inner circumferential surface of the outer sleeve and the outermost spacer, the constant strain design of the multiple rubber bodies located between the outer sleeve, mandrel, and multiple spacers after vulcanization is achieved.

[0010] Preferably, in the axial section of the conical spring, the angle between the inclined line of the conical spacer located on one side of the central axis of the conical spring and the central axis of the conical spring is set as θ1, so that θ1 is equal for each spacer, and the angle between the inclined line of the inner circumferential surface of the outer sleeve located on one side of the central axis of the conical spring and the central axis of the conical spring is set as θ2. The specific steps of the method for achieving constant strain design of the rubber layer of a conical spring within a limited space are as follows: First, the inclined line at the position of the inner circumferential surface of the outer jacket located on one side of the central axis of the conical spring is set to be parallel to the inclined line at the position of the conical spacer located on one side of the central axis of the conical spring. While ensuring that the outer diameter of the outer jacket remains unchanged, the inclined line at the position of the inner circumferential surface of the outer jacket is moved parallel to the central axis of the conical spring to the inclined line P, so that the radial width of the annular end of the outer jacket is greater than the diameter of the end screw hole. The inclined line P intersects the horizontal line extending horizontally along the annular end of the upper end of the outer jacket at point S. Then, with point S as the center, the inclined line P is rotated by a certain angle away from the central axis of the conical spring to obtain the inclined line Q, so that the inclined line at the position of the inner circumferential surface of the outer jacket is moved to the inclined line Q. Then, θ2 > θ1, so as to increase the gap between the inner circumferential surface of the outer jacket and the outermost spacer. Through the above steps, the constant strain design of multiple rubber bodies located between the outer jacket, the mandrel and multiple spacers after vulcanization is achieved.

[0011] Preferably, a lower conical spacer is also provided at the lower end of the conical spacer, and the angle between the inclined line of the inner circumferential surface of the lower conical spacer located on one side of the central axis of the conical spring and the central axis of the conical spring is set to θ3, then θ3 > θ1; When the conical spring is subjected to vertical pressure, the rubber body located at the lower end of the conical spacer deforms and bulges out to contact the lower conical spacer, thus realizing the characteristic that the vertical stiffness of the spring series increases non-linearly with the increase of load.

[0012] Preferably, the included angle θ1 ≤ 7°.

[0013] Preferably, the included angle θ3 is ≥ 28°.

[0014] Preferably, an annular spacer is also provided at the upper end of the conical spacer.

[0015] Preferably, the lower end face of the rubber body is configured as an inverted face, which includes an arc-shaped face, a first inclined face located at the upper end of the arc-shaped face, and a second inclined face located at the lower end of the arc-shaped face.

[0016] Preferably, a cover is also provided at the upper end of the outer sleeve of the conical spring, and the damping adjustment space is formed by the enclosure between the cover and the upper end of the conical spring. When a high stiffness is required for the conical spring, gas is introduced into the damping adjustment space; when a high stiffness is not required for the conical spring, the gas in the damping adjustment space is discharged.

[0017] Preferably, a gas passage is provided on the cover, and the gas passage is connected to the damping adjustment space; When gas is introduced into the damping adjustment space, it is injected into the damping adjustment space through the gas through hole. After the injection is completed, the sealing plug is inserted into the gas through hole for sealing. When gas needs to be discharged, the sealing plug is removed. When the conical spring is compressed, the gas in the damping adjustment space will be automatically discharged through the gas through hole.

[0018] Preferably, a stepped portion is provided on the annular end of the upper part of the outer cover, and a sealing ring is also provided in the stepped portion, and the cover is press-fitted into the stepped portion.

[0019] The beneficial effects of this invention are as follows: Through the design method of this invention, within a limited space, the conical spring can ensure that sufficient space is reserved at the annular end of its outer sleeve for machining the end screw hole, and that each rubber body achieves a state of uniform strain under pressure. This prevents defects such as cracks and damage to the rubber body during use, avoiding premature failure and thus improving the product's service life and performance. By setting a lower conical spacer at the lower end of the conical spacer, the vertical stiffness of the spring series increases non-linearly with increasing load. By setting the lower end face of the rubber body as an inverted surface, the amount of rubber and wrinkles in the non-working area are reduced, increasing the strain space of the rubber during operation and ensuring a single-layer uniform strain design. By setting a damping adjustment space, the stiffness of the product can be adjusted according to the actual working requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the axial cross-sectional structure of a conical spring in the prior art; Figure 2 for Figure 1 A partial structural diagram of the area between the outermost layer and the innermost spacer; Figure 3 This is a schematic diagram illustrating the principle of the design method in an embodiment of the present invention; Figure 4 This is a schematic diagram of the axial cross-sectional structure of the conical spring in an embodiment of the present invention; Figure 5 This is a schematic diagram of the axial cross-sectional structure of the spacer in an embodiment of the present invention; Figure 6 for Figure 4 Enlarged structural diagram of section A in the middle; Figure 7 for Figure 4 Enlarged structural diagram of section B in the middle; In the diagram: 1. Outer sleeve, 111. Annular end, 112. Stepped section, 2. Mandrel, 3. Spacer, 4. Rubber body, 411. Arc-shaped surface, 412. Sloping surface one, 413. Sloping surface two, 5. End screw hole, 6. Lower conical spacer, 7. Annular spacer, 8. Cover, 811. Gas passage, 9. Damping adjustment space, 10. Sealing ring. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] The applicant, after research, found that, Figure 2 As shown, during the design process, it is necessary to consider the equal strain design of each rubber layer. The equal strain design of rubber layers refers to using the equal strain principle to consider the strain and stress distribution of the rubber material during the design of rubber products, in order to ensure the performance and lifespan of the product. Therefore, under the premise of equal strain design of the rubber layers, theoretically, the tilt angles of the spacer 3 and the outer sleeve 1 should be designed according to the concept of θ1=θ2, so that each layer of rubber 4 is in an equal strain state. In this case, theoretically, the tilt line M at the position of the inner circumference surface of the outer sleeve 1 should be located outside the tilt line N at the actual position of the inner circumference surface of the outer sleeve 1 (i.e., away from the central axis L of the conical spring). Let the distance between the tilt line M and the outermost spacer 3 be H1. However, since the outer diameter Φ of the outer sleeve 1 is fixed and cannot be changed, the design space is limited. At the same time, an end screw hole 5 needs to be opened on the annular end 111 of the outer sleeve 1. At this time, since the reserved size of the radial width D of the annular end 111 is insufficient, the inclined line M at the theoretical position of the inner circumferential surface of the outer sleeve 1 will interfere with the end screw hole 5. Therefore, it is impossible to process the end screw hole 5 on the annular end 111. In order to leave enough radial width D to process the end screw hole 5, the inclined line M at the theoretical position of the inner circumferential surface of the outer sleeve 1 must be shifted inward (i.e., closer to the central axis L of the conical spring) to the position of the inclined line N. Let the distance between the inclined line N and the outermost spacer 3 be H2. It can be seen that H2 < H1. In fact, H1 and H2 represent the thickness of the rubber body 4 between the outer jacket 1 and the outermost spacer 3. When H2 < H1, it means that the actual thickness of the rubber body 4 between the outer jacket 1 and the outermost spacer 3 is less than the theoretical thickness of the rubber body 4 between the outer jacket 1 and the outermost spacer 3. This will cause the rubber bodies to not be in a state of equal strain when the product is under pressure, and the rubber bodies will always have defects such as cracks and damage, resulting in rubber failure, which in turn affects the service life and performance of the product.

[0023] Therefore, such as Figure 3 and Figure 4As shown, in the design, the applicant sets the inner circumferential surface of the outer sleeve 1 into a conical shape. First, the inclined line of the inner circumferential surface of the outer sleeve 1, located on one side of the central axis L of the conical spring, is set parallel to the inclined line of the conical spacer 3, also located on one side of the central axis L of the conical spring. With the outer diameter Φ of the outer sleeve 1 fixed, the inclined line of the inner circumferential surface of the outer sleeve 1 is moved parallel to the central axis L of the conical spring to the inclined line P. This makes the radial width D of the annular end 111 of the outer sleeve 1 greater than the diameter of the end screw hole 5, thus reserving sufficient space for machining the end screw hole 5. Because it is a parallel movement... Therefore, the angle between the inclined line P and the central axis L of the conical spring is equal to θ1. The inclined line P intersects the horizontal line extending horizontally along the annular end 111 at the upper end of the outer sleeve 1 at point S. Then, with point S as the center, the inclined line P is rotated by a certain angle away from the central axis L of the conical spring to obtain the inclined line Q, so that the inclined line at the position of the inner circumferential surface of the outer sleeve 1 is located on the inclined line Q. At this time, the angle θ2 between the inclined line at the position of the inner circumferential surface of the outer sleeve 1 on the side of the central axis L of the conical spring and the central axis L of the conical spring is greater than the angle θ1 between the inclined line at the position of the conical spacer 3 on the side of the central axis L of the conical spring and the central axis L of the conical spring. In this embodiment, since the inclined line P is rotated by a certain angle away from the central axis L of the conical spring, i.e., the angle θ2 > the angle θ1, from Figure 3 As can be seen, the gap H3 between the inclined line Q and the outermost spacer 3 is actually greater than the gap H4 between the inclined line P and the outermost spacer 3. This design, while ensuring sufficient space is reserved at the annular end 111 of the outer jacket 1 for machining the end screw hole 5, increases the thickness of the rubber body 4 between the outer jacket 1 and the outermost spacer 3. This ensures that the rubber bodies achieve a state of equal strain when the product is under pressure. In summary, through the above design method, within a limited space, the conical spring can ensure that sufficient space is reserved at the annular end of its outer jacket for machining the end screw hole, and also ensure that the rubber bodies achieve a state of equal strain when the product is under pressure. This prevents the conical spring from frequently developing defects such as cracks and damage to the rubber body during use, avoiding premature failure of the rubber body, thereby improving the service life and performance of the product.

[0024] The tapered spring, typically used as the primary spring, allows for significant vertical displacement of the axle box relative to the frame during vehicle operation. The lateral and longitudinal relative displacements between the wheelset and the frame are achieved through the deformation of the primary spring. Therefore, specific requirements are placed on the elastic stiffness of the primary spring in the vertical, lateral, and longitudinal directions. Furthermore, under different vertical loads, the vertical stiffness of the primary spring is required to increase non-linearly with increasing load. Figure 5As shown, the applicant has also provided a lower conical spacer 6 at the lower end of the conical spacer 3. The conical spacer 3 and the lower conical spacer 6 can be integrated into one structure. The angle between the inclined line of the inner circumferential surface of the lower conical spacer 6 located on one side of the central axis L of the conical spring and the central axis L of the conical spring is set to θ3, where θ3 > θ1. This effectively creates an outwardly extending section at the lower end of the conical spacer 3. When the product is subjected to vertical pressure, the rubber body at the lower end of the conical spacer deforms and bulges out, contacting the lower conical spacer 6, thus realizing the characteristic that the vertical stiffness of the primary spring increases non-linearly with increasing load. Through experiments, θ1 ≤ 7° can be set, which improves the lateral stiffness of the primary spring and achieves the requirement of a lateral to vertical stiffness ratio of 7.6 or higher. Setting θ3 ≥ 28° can achieve the requirement of more than doubling the vertical non-linear stiffness increment of the primary spring, reduce the vertical creep of the primary spring, and improve the fatigue life of the primary spring.

[0025] An annular spacer 7 is also provided at the upper end of the conical spacer 3. The conical spacer 3, the lower conical spacer 6, and the annular spacer 7 can also be configured as an integral structure. By providing the annular spacer 7, the upper end of the conical spacer 3 extends vertically upward, which facilitates the demolding of the conical spring after vulcanization.

[0026] like Figure 6 The lower end face of the rubber body 4 is set as an inverted face, which includes an arc-shaped face 411, a first inclined face 412 set at the upper end of the arc-shaped face 411, and a second inclined face 413 set at the lower end of the arc-shaped face 411. This reduces the amount of rubber and wrinkles in the non-working area, increases the strain space of the rubber during operation, and ensures the design of uniform strain in a single layer.

[0027] like Figure 4 As shown, a cover 8 is also provided at the upper end of the outer sleeve 1 of the conical spring. The cover 8 and the upper end of the conical spring are used to form a damping adjustment space 9. When a larger stiffness of the conical spring is required, gas, such as compressed air or inert gas, can be filled into the damping adjustment space 9. At this time, the stiffness of the product is actually equal to the stiffness of the conical spring plus the stiffness of the gas, which can meet the larger stiffness requirement. When a larger stiffness is not required, the gas in the damping adjustment space 9 can be discharged.

[0028] A gas passage 811 is provided on the cover 8, which communicates with the damping adjustment space 9. When gas is introduced into the damping adjustment space 9, it is injected into the damping adjustment space 9 through the gas passage 811. After injection, a sealing plug (not shown in the figure) is inserted into the gas passage 811 for sealing. When it is necessary to release the gas, simply remove the sealing plug, and when the conical spring is compressed, the gas in the damping adjustment space 9 will automatically be released through the gas passage 811.

[0029] like Figure 7 As shown, a full-circle stepped portion 112 is provided on the annular end 111 at the upper end of the outer jacket 1. A sealing ring 10 is also provided in the stepped portion 112. The cover 8 is press-fitted into the stepped portion 112, which can improve the sealing performance of the damping adjustment space 9.

[0030] In summary, the design method of this invention ensures that, within a limited space, the conical spring has sufficient space at the annular end of its outer sleeve for machining the end screw hole, while also guaranteeing that all rubber components maintain a uniform strain state under pressure. This prevents frequent cracking and damage to the rubber components during use, avoiding premature failure and thus improving the product's service life and performance. By setting a lower conical spacer at the lower end of the conical spacer, the vertical stiffness of the spring series increases non-linearly with increasing load. By designing the lower end face of the rubber component as an inverted shape, the amount of rubber and wrinkles in the non-working area are reduced, increasing the strain space during operation and ensuring a single-layer uniform strain design. The damping adjustment space allows the product's stiffness to be adjusted according to the actual working requirements.

[0031] In this embodiment, "multiple" refers to "two or more". The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of this invention, which is defined by the claims.

Claims

1. A method for achieving equal strain design of a conical spring rubber layer within a limited space, wherein the conical spring includes an outer sleeve (1), a mandrel (2), and multiple spacers (3) located between the outer sleeve (1) and the mandrel (2), the outer sleeve (1), the mandrel (2), and the multiple spacers (3) are bonded together by multiple rubber bodies (4) through vulcanization, the inner circumferential surface of the outer sleeve (1) and the spacers (3) are both set in a conical shape, and an end screw hole (5) is also opened on one end of the outer sleeve (1) at an annular end (111), characterized in that: The method for achieving equal strain design of the rubber layer of the conical spring in a limited space is to extend the radial width (D) of the annular end (111) toward the central axis (L) of the conical spring while keeping the outer diameter (Φ) of the outer sleeve (1) fixed to ensure the processing of the end screw hole (5), and then achieve equal strain design of multiple rubber bodies (4) located between the outer sleeve (1), the mandrel (2) and multiple spacers (3) after vulcanization by increasing the gap between the inner circumferential surface of the outer sleeve (1) and the outermost spacer (3); In the axial section of the conical spring, the angle between the inclined line of the conical spacer (3) located on one side of the central axis (L) of the conical spring and the central axis (L) of the conical spring is set as θ1, then the θ1 of each spacer (3) is equal, and the angle between the inclined line of the inner circumferential surface of the outer sleeve (1) located on one side of the central axis (L) of the conical spring and the central axis (L) of the conical spring is set as θ2. The specific steps of the method for implementing equal strain design of the rubber layer of the conical spring in a limited space are as follows: First, the inclined line of the inner circumferential surface of the outer sleeve (1) located on one side of the central axis (L) of the conical spring is set to be parallel to the inclined line of the conical spacer (3) located on one side of the central axis (L) of the conical spring. While ensuring that the outer diameter (Φ) of the outer sleeve (1) remains unchanged, the inclined line of the inner circumferential surface of the outer sleeve (1) is moved parallel to the central axis (L) of the conical spring to the inclined line P, so that the radial width (D) of the annular end (111) of the outer sleeve (1) is greater than the end screw hole (5). The diameter of the inclined line P intersects the horizontal line extending horizontally along the annular end (111) at the upper end of the outer jacket (1) at point S. Then, with point S as the center, the inclined line P is rotated at a certain angle away from the central axis (L) of the conical spring to obtain the inclined line Q, so that the inclined line at the position of the inner circumferential surface of the outer jacket (1) moves to the inclined line Q. Then θ2 > θ1, so as to increase the gap between the inner circumferential surface of the outer jacket (1) and the outermost spacer (3). Through the above steps, the equal strain design of multiple rubber bodies (4) located between the outer jacket (1), the mandrel (2) and multiple spacers (3) after vulcanization is achieved.

2. The method for achieving constant strain design of a conical spring rubber layer in a limited space according to claim 1, characterized in that: A lower conical sleeve (6) is also provided at the lower end of the conical sleeve (3). The angle between the inclined line of the inner circumferential surface of the lower conical sleeve (6) located on one side of the central axis (L) of the conical spring and the central axis (L) of the conical spring is set to θ3, then θ3 > θ1. When the conical spring is subjected to vertical pressure, the rubber body at the lower end of the conical spacer (3) deforms and bulges out to contact the lower conical spacer (6), thus realizing the characteristic that the vertical stiffness of the spring increases non-linearly with the increase of load.

3. The method for achieving constant strain design of the rubber layer of a conical spring in a limited space according to claim 2, characterized in that: The included angle θ1 ≤ 7°.

4. The method for achieving constant strain design of the rubber layer of a conical spring in a limited space according to claim 3, characterized in that: The included angle θ3 ≥ 28°.

5. The method for achieving constant strain design of the rubber layer of a conical spring in a limited space according to claim 2, characterized in that: An annular spacer (7) is also provided at the upper end of the conical spacer (3).

6. The method for achieving constant strain design of a conical spring rubber layer in a limited space according to claim 1, characterized in that: The lower end face of the rubber body (4) is set as an inverted surface, which includes an arc surface (411), a first inclined surface (412) set at the upper end of the arc surface (411), and a second inclined surface (413) set at the lower end of the arc surface (411).

7. The method for achieving constant strain design of a conical spring rubber layer in a confined space according to any one of claims 1 to 6, characterized in that: A cover (8) is provided at the upper end of the outer sleeve (1) of the conical spring, and a damping adjustment space (9) is formed by the enclosure between the cover (8) and the upper end of the conical spring. When a large stiffness is required for the conical spring, gas is introduced into the damping adjustment space (9); when a large stiffness is not required for the conical spring, the gas in the damping adjustment space (9) is discharged.

8. The method for achieving constant strain design of a conical spring rubber layer in a limited space according to claim 7, characterized in that: A gas through hole (811) is provided on the cover (8), and the gas through hole (811) is connected to the damping adjustment space (9); When gas is filled into the damping adjustment space (9), the gas is injected into the damping adjustment space (9) through the gas through hole (811). After the injection is completed, the sealing plug is inserted into the gas through hole (811) for sealing. When the gas needs to be discharged, the sealing plug is removed. When the conical spring is compressed, the gas in the damping adjustment space (9) will be automatically discharged through the gas through hole (811).

9. The method for achieving constant strain design of a conical spring rubber layer in a limited space according to claim 7, characterized in that: A stepped portion (112) is provided on the annular end (111) at the upper end of the outer jacket (1), and a sealing ring (10) is also provided in the stepped portion (112). The cover (8) is press-fitted into the stepped portion (112).

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