Hydraulic bushing and production process thereof

Abstract

The hydraulic bushing sequentially comprises a main spring, a runner plate and a bushing support from inside to outside, the runner plate and the bushing support are matched with the main spring, the bushing support is in sealed connection with the main spring, and the space between the bushing support and the main spring is filled with liquid; the main spring comprises an inner pipe, main spring rubber and a ball cage which are sequentially connected from inside to outside. The hydraulic bushing still has a reliable damping effect under the condition that the hydraulic bushing is not provided with an outer sleeve any more. Due to the fact that an outer sleeve is omitted from the hydraulic bushing, local excessive extrusion or deformation of the outer sleeve is avoided, and the qualification rate of the hydraulic bushing is increased. And the manufacturing cost of the hydraulic bushing can be saved by eliminating the outer sleeve.

Description

Technical Field

[0001] This invention relates to the field of hydraulic bushing production, and more specifically, to a hydraulic bushing and its production process. Background Technology

[0002] Hydraulic bushings and bushing brackets are key connecting components widely used in modern automotive suspension systems. They are primarily used to connect the subframe and control arms to attenuate vibrations and impacts transmitted from the road surface to the vehicle body, thereby improving ride comfort and handling stability through frequency shielding. This subassembly typically consists of an internal hydraulic bushing skeleton and an external metal bushing bracket, which are assembled together with an interference fit.

[0003] Currently, the industry commonly uses a press-fitting machine to press the hydraulic bushing into the bushing bracket. The specific process is as follows: first, the bushing bracket is positioned on the worktable of the submersible press-fitting machine, then the hydraulic bushing skeleton is placed above the bushing bracket mounting hole, and axial pressure is applied by the press head, so that the bushing is embedded into the inner hole of the bracket under continuous mechanical pressure until the predetermined installation depth is reached.

[0004] Because the outer tube is made of aluminum, if the pressure control is inaccurate or the pressing is not properly aligned during the pressing process, the outer tube of the bushing is easily subjected to excessive local compression or deformation, resulting in a high product scrap rate. Summary of the Invention

[0005] The purpose of this invention is to provide a hydraulic bushing and its manufacturing process, which maintains reliable shock absorption without requiring an outer sleeve. Because the outer sleeve is eliminated, localized excessive compression or deformation of the outer sleeve is prevented, thus improving the yield rate of the hydraulic bushing. Furthermore, eliminating the outer sleeve also reduces manufacturing costs.

[0006] To achieve the above objectives, the present invention provides a hydraulic bushing, which includes, from the inside out, a main spring, a flow channel plate that cooperates with the main spring, and a bushing bracket. The bushing bracket and the main spring are sealed together, and the space between the bushing bracket and the main spring is filled with liquid. The main spring consists of an inner tube, a main spring rubber, and a ball cage connected sequentially from the inside out.

[0007] The present invention also provides a manufacturing process for a hydraulic bushing, wherein the main spring and the flow channel plate are fitted together and then pressed and fixed to the bushing bracket by a submersible filling machine.

[0008] Preferably, the main spring and the bushing bracket are interference-fitted.

[0009] Preferably, the inner tube, the main spring rubber, and the ball cage are vulcanized to obtain the main spring.

[0010] Preferably, the bushing support is produced by an extrusion process.

[0011] Preferably, sealing rings are provided at both ends of the bushing bracket to cooperate with the main spring to achieve a seal.

[0012] Preferably, the sealing ring and the bushing support are configured as an integral structure, and the inner diameter of the sealing ring gradually decreases along the direction away from the bushing support.

[0013] Preferably, the inner diameter of the bushing support extruded is consistent with the outer diameter of the sealing ring.

[0014] Preferably, the assembly surface of the bushing bracket is machined to ensure the dimensional accuracy of the mating surfaces.

[0015] According to the above technical solution, the present invention eliminates the outer sleeve of the bushing and no longer uses the outer sleeve to seal the liquid inside the hydraulic bushing. Instead, the main spring and the bushing support are directly sealed, and the liquid is sealed between the bushing support and the main spring.

[0016] In this hydraulic bushing, the main spring is the core elastic load-bearing and connecting component. It consists of a three-layer structure: an inner tube, a main spring rubber, and a ball cage. The inner tube is directly press-fitted or connected to the vehicle frame or control arm. The bushing bracket opening connects to the subframe. The inner tube is the main force input point and static connector. The main spring rubber is used for load bearing and vibration isolation. As an elastic body, the main spring rubber bears the static load and dynamic vibration from the inner tube. Its core function is to attenuate and isolate high-frequency, low-amplitude vibrations, such as engine idling vibrations and minor road surface unevenness. The ball cage is a molded skeleton that provides support for the main spring rubber during vulcanization molding, ensuring the structural strength and shape accuracy of the main spring.

[0017] During use, the main spring provides radial and axial stiffness to the hydraulic bushing, determining the bushing's basic stiffness and elastic characteristics. The main spring rubber mates with the ball cage and flow channel plate. When vibration occurs, the main spring rubber deforms. As the main spring rubber deforms, the fluid located between the bushing support and the main spring is driven to flow from one chamber to another. During the fluid flow, the hydraulic bushing provides hydraulic damping.

[0018] The ball cage, as the outermost layer of the main spring, mates with the flow channel plate. The inner wall of the bushing aluminum bracket and the vulcanized main spring form multiple hydraulic chambers. Liquid channels are provided on the flow channel plate to connect these chambers. The flow channel plate is designed with specific inertial channels or decoupling disk structures. These channels connect the liquid chambers on both sides of the bushing. When the main spring deforms under stress, it compresses one side of the liquid chamber, forcing liquid to flow through narrow channels on the flow channel plate into the other side. The liquid flow through these narrow channels generates a significant damping or inertial effect, thereby consuming energy and altering the dynamic stiffness of the bushing.

[0019] Therefore, hydraulic bushings utilize the elasticity of the main spring rubber to isolate high-frequency, low-amplitude vibrations, ensuring vehicle comfort during driving; and by utilizing the damping effect of the flow channel plate on the liquid flow, they can efficiently attenuate and suppress low-frequency, high-amplitude vibrations or impacts, such as starting jitter and bump impacts.

[0020] This hydraulic bushing maintains reliable vibration damping even without an outer sleeve. Because the outer sleeve is eliminated, localized excessive compression or deformation of the outer sleeve is prevented, thus improving the yield rate of the hydraulic bushing. Furthermore, eliminating the outer sleeve also reduces manufacturing costs.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a hydraulic bushing; Figure 2 This is a cross-sectional view of a hydraulic bushing; Figure 3 This is a schematic diagram of a bushing bracket; Figure 4 This is a cross-sectional view of a bushing support.

[0023] Explanation of reference numerals in the attached figures Detailed Implementation

[0024] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] In this invention, unless otherwise stated, directional terms such as "one end," "the other end," "outer surface," "axis," "conical," and "near" in the terminology represent only the orientation of the term in its conventional use or are common terms understood by those skilled in the art, and should not be regarded as limitations on the term.

[0026] See Figure 1-2 The hydraulic bushing, from the inside out, includes a main spring 1, a flow channel plate 2 that cooperates with the main spring 1, and a bushing bracket 3. The bushing bracket 3 is sealed to the main spring 1, and the space between the bushing bracket 3 and the main spring 1 is filled with liquid. The main spring 1 includes an inner tube 11, a main spring rubber 12, and a ball cage 13 connected sequentially from the inside to the outside.

[0027] By implementing the above technical solution, the hydraulic bushing eliminates the outer sleeve of the bushing and no longer uses the outer sleeve to seal the liquid inside the hydraulic bushing. Instead, the main spring 1 and the bushing bracket 3 are directly sealed, and the liquid is sealed between the bushing bracket 3 and the main spring 1.

[0028] In this hydraulic bushing, the main spring 1 is the core elastic load-bearing and connecting component of the hydraulic bushing. It consists of a three-layer structure: an inner tube 11, a main spring rubber 12, and a ball cage 13. The inner tube is directly press-fitted or connected to the vehicle frame or control arm. The bushing bracket opening connects to the subframe. The inner tube is the main force input point and static connection component. The main spring rubber 12 is used for load bearing and vibration isolation. As an elastic body, the main spring rubber 12 bears the static load and dynamic vibration from the inner tube 11. Its core function is to attenuate and isolate high-frequency, low-amplitude vibrations, such as engine idling vibrations and minor road surface unevenness. The ball cage 13 is a molded skeleton that provides a supporting skeleton for the vulcanization molding of the main spring rubber 11, ensuring the structural strength and shape accuracy of the main spring 1.

[0029] During use, the main spring 1 provides radial and axial stiffness to the hydraulic bushing, determining the bushing's basic stiffness and elastic characteristics. The main spring rubber 12 cooperates with the ball cage and flow channel plate. When vibration occurs, the main spring rubber 12 deforms. As the main spring rubber 12 deforms, the liquid located between the bushing support 3 and the main spring 1 is driven to flow from one chamber to another. During the liquid flow, the hydraulic bushing achieves hydraulic damping.

[0030] The ball cage 13, as the outermost layer of the main spring, mates with the flow channel plate 2. The inner wall of the bushing support 32 and the main spring form multiple liquid chambers. Liquid channels are provided on the flow channel plate 2, connecting to these chambers and guiding the liquid flow between them. The flow channel plate 2 is designed with specific inertial channels or decoupling disk structures. These channels connect the liquid chambers on both sides of the bushing. When the main spring 1 deforms under force, it compresses one side of the liquid chamber, forcing the liquid to flow through the narrow channels on the flow channel plate 2 into the other side's liquid chamber. The liquid flow through the narrow channels generates a significant damping or inertial effect, thereby consuming energy and changing the dynamic stiffness of the bushing.

[0031] Therefore, the hydraulic bushing utilizes the elasticity of the main spring rubber 12 to isolate high-frequency small-amplitude vibrations, ensuring the comfort of the vehicle during driving; the flow channel plate 2 generates a damping effect on the liquid flow, which can efficiently attenuate and suppress low-frequency large-amplitude vibrations or impacts, such as starting jitter and bump impacts.

[0032] This hydraulic bushing maintains reliable vibration damping even without an outer sleeve. Because the outer sleeve is eliminated, localized excessive compression or deformation of the outer sleeve is prevented, thus improving the yield rate of the hydraulic bushing. Furthermore, eliminating the outer sleeve also reduces manufacturing costs.

[0033] The present invention also provides a production process for a hydraulic bushing, wherein the main spring 1 and the flow channel plate 2 are fitted together and then pressed and fixed to the bushing bracket 3 by a submersible filling machine.

[0034] The submersible filling machine is filled with a special liquid. First, the bushing support 3 is placed in the liquid. Then, the main spring 1 and the flow channel plate 2 are fitted together and placed on top of the bushing support 3. The bushing support 3, main spring 1, and flow channel plate 2 are all submerged in the liquid. The filling equipment is started to press the main spring 1 downwards until the main spring 1 and flow channel plate 2 are completely pressed into the bushing support 3. After the pressing is completed, the gap between the bushing support 3 and the main spring 1 is completely filled with liquid. This liquid provides damping for the hydraulic bushing.

[0035] This liquid has a low viscosity index, with viscosity changing little with temperature, thus ensuring stable damping performance under different ambient temperatures. It also exhibits excellent low-temperature fluidity, preventing solidification in extremely cold weather and ensuring normal bushing operation even at low temperatures. It is highly compatible with rubber, preventing swelling, aging, or performance degradation of the main spring rubber. Furthermore, it possesses anti-wear and anti-foaming properties, maintaining performance under long-term high-frequency vibration without easily generating bubbles, and also needs good damping characteristics to aid energy dissipation. In one embodiment, the liquid is configured as ethylene glycol-based hydraulic oil or polypropylene glycol-based oil.

[0036] The space between the bushing support 3 and the main spring 1 needs to be purged of air and filled with liquid. If there is air in the cavity of the hydraulic bushing, the gas will be compressed under high pressure, forming bubbles. When the pressure changes abruptly, the bubbles will burst, generating impact and noise, severely weakening the damping effect, and potentially damaging the structure. Moreover, air is compressible during use, while the specialized hydraulic oil is almost incompressible. Only by completely filling the cavity with incompressible liquid can the deformation of the rubber be converted into liquid pressure instantaneously and without delay, generating the precisely designed damping force through the flow channel plate 2. Therefore, even the smallest air bubble between the bushing support 3 and the main spring 1 will lead to unstable and degraded bushing performance.

[0037] After the main spring 1 is fitted with the flow channel plate 2, it is pressed and fixed to the bushing bracket 3 by a submersible filling machine, which can reliably remove air. This is the key to ensuring the stable performance and silent operation of the bushing throughout its entire life cycle. Using the bushing bracket 3 instead of the outer sleeve of the bushing to seal the liquid saves costs and also achieves the shock absorption effect of the hydraulic bushing.

[0038] In this embodiment, preferably, the main spring 1 and the bushing bracket 3 are interference-fitted.

[0039] The main spring 1 and the bushing bracket 3 are fitted together by the main spring rubber 12. The main spring rubber 12 can be compressed. During the pressing process, the main spring rubber 12 is first compressed so that it can enter the inner hole 33 of the bushing bracket 3. After entering the inner hole 33, the main spring rubber 12 expands and presses tightly against the inner wall of the bushing bracket 3, thereby achieving a sealing effect. Therefore, by setting the main spring 1 and the bushing bracket 3 with an interference fit, the contact between the main spring rubber 12 and the inner wall of the bushing bracket 3 can maintain a certain pressure at the contact position, thereby achieving the sealing effect of the liquid in the hydraulic bushing.

[0040] In this embodiment, preferably, the inner tube 11, the main spring rubber 12, and the ball cage 13 are vulcanized to obtain the main spring 1.

[0041] The inner tube 11 is a metal mandrel, and the ball cage 13 is a metal outer sleeve. Before the vulcanization process, the inner tube 11 and the ball cage 13 are precisely fixed in the corresponding cavities of the mold, with a pre-designed space between them. This space is used to form the main spring rubber 12. After the inner tube 11 and the ball cage 13 are fixed, raw rubber is injected into the mold cavity. Unvulcanized, viscous raw rubber material is injected or pre-placed into the pre-designated space.

[0042] The mold is then closed and held at high temperature (e.g., 160-180°C) and high pressure for a period of time. During this process, the rubber undergoes a cross-linking reaction, transforming from a linear polymer structure into a three-dimensional network structure, ultimately yielding the main spring 1 with certain elasticity, strength, and durability.

[0043] During the vulcanization process, the rubber not only cures itself, but the adhesive system in its formulation also chemically reacts with the metal surfaces of the inner tube 11 and the ball cage 13, forming an extremely strong chemical-physical bond. Under the action of this chemical-physical bond, the hydraulic bushing can withstand repeated liquid pressure and deformation without the rubber peeling off from the metal, thus ensuring the reliability of the hydraulic bushing during operation. Moreover, the vulcanized bonding surface between the ball cage 13 and the main spring rubber 12 is an absolute guarantee for the sealing of the hydraulic chamber interior. This chemical-physical bonding interface prevents high-pressure liquid from seeping in and peeling off the rubber, ensuring the long-term effectiveness of the hydraulic system.

[0044] After cooling and demolding, the inner tube 11, the main spring rubber 12, and the ball cage 13 become a composite component. In this composite component, the ball cage 13 provides rigid support and strength for the main spring 1, while the main spring rubber 12 provides elastic damping for the main spring 1.

[0045] Preferably, the vulcanizing mold can precisely control the shape, thickness, and pre-compression of the rubber part, which directly determine the static stiffness, deformation limit, and fatigue life of the main spring.

[0046] In this embodiment, preferably, the bushing support 3 is produced by an extrusion process.

[0047] Since the bushing bracket 3 no longer needs to be fitted with the outer sleeve, the requirements for the dimensional accuracy and surface roughness of the inner wall of the bushing bracket 3 are reduced accordingly. Therefore, the precision requirements for machining of the inner wall of the bushing bracket 3 are reduced, which can save the manufacturing cost of the bushing bracket 3.

[0048] The bushing bracket 3 is produced by an extrusion process. During extrusion, a blank of a fixed length is extruded according to the cross-sectional shape of the bushing bracket 3. Then, according to the actual length of the bushing bracket 3, the blank is cut into multiple intermediate parts, and the intermediate parts are then processed to obtain the bushing bracket 3.

[0049] This method of extruding and cutting the bushing bracket 3 can not only reduce the processing cost of the bushing bracket 3, but also improve the production efficiency of the bushing bracket 3.

[0050] In this embodiment, preferably, sealing rings 14 are provided at both ends of the bushing bracket 3 to cooperate with the main spring 1 to achieve sealing.

[0051] In this embodiment, preferably, the sealing ring 14 and the bushing bracket 3 are configured as an integral structure, and the inner diameter of the sealing ring 14 gradually decreases along the direction away from the bushing bracket 3.

[0052] After the main spring 1 is pressed into the bushing bracket 3, the two ends of the main spring 1 will cooperate with the sealing rings 14 at both ends of the bushing bracket 3 to seal the liquid inside the bushing bracket 3.

[0053] The inner diameter of the sealing ring 14 gradually decreases in the direction away from the bushing bracket 3. The main spring 1 and the bushing bracket 3 are interference-fitted. Therefore, the sealing ring 14 will exert a certain pressure on the end of the main spring 1. Under the action of this pressure, the main spring rubber 12 will deform. The deformed main spring rubber 12 will also exert elastic pressure on the sealing ring 14 at the contact position. This elastic pressure ensures that the sealing ring 14 and the main spring 1 can always be reliably fitted. Through this reliable fit, the liquid can be effectively sealed.

[0054] In addition, the inner diameter of the sealing ring 14 gradually decreases along the direction away from the bushing bracket 3, so that the deformation of the main spring rubber 12 is greater towards both ends of the hydraulic bushing. That is, along the length of the sealing ring, the sealing effect of the main spring rubber 12 and the sealing ring 14 gradually increases, thereby reliably ensuring the sealing effect.

[0055] Moreover, the convergence effect of the sealing ring 14 can reliably position the main spring 1 located therein.

[0056] In this embodiment, preferably, the inner diameter of the bushing bracket 3 extruded is consistent with the outer diameter of the sealing ring 14.

[0057] The inner diameter of the bushing bracket 3 extruded is consistent with the outer diameter of the sealing ring 14. After the blank is cut into an intermediate part, the inner hole of the intermediate part needs to be processed. By cutting the inner hole, the middle part of the intermediate part forms the inner hole 33 of the bushing bracket 3, while the two ends of the intermediate part are cut into the cone shape shown in the figure to form the sealing ring 14.

[0058] In this embodiment, preferably, the assembly surface 31 of the bushing bracket 3 is machined to ensure the dimensional accuracy of the mating surface.

[0059] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0060] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0061] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A hydraulic bushing, characterized in that, From the inside out, it includes a main spring (1), a flow channel plate (2) that cooperates with the main spring (1), and a bushing bracket (3). The bushing bracket (3) is sealed to the main spring (1), and the space between the bushing bracket (3) and the main spring (1) is filled with liquid. The main spring (1) includes an inner tube (11), a main spring rubber (12), and a ball cage (13) connected sequentially from the inside to the outside.

2. A manufacturing process for a hydraulic bushing, characterized in that, After the main spring (1) and the flow channel plate (2) are fitted together, they are pressed and fixed by the submersible filling machine and the bushing bracket (3).

3. The production process according to claim 2, characterized in that, The main spring (1) and the bushing bracket (3) are interference fit.

4. The production process according to claim 2, characterized in that, The inner tube (11), the main spring rubber (12) and the ball cage (13) are vulcanized to obtain the main spring (1).

5. The production process according to claim 2, characterized in that, The bushing bracket (3) is produced by extrusion process.

6. The production process according to claim 5, characterized in that, The bushing bracket (3) is provided with sealing rings (14) at both ends for use with the main spring (1) to achieve sealing.

7. The production process according to claim 6, characterized in that, The sealing ring (14) and the bushing bracket (3) are set as an integral structure, and the inner diameter of the sealing ring (14) gradually decreases along the direction away from the bushing bracket (3).

8. The production process according to claim 7, characterized in that, The inner diameter of the bushing bracket (3) is the same as the outer diameter of the sealing ring (14).

9. The production process according to claim 5, characterized in that, The assembly surface (31) of the bushing bracket (3) is machined to ensure the dimensional accuracy of the mating surface.

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