Sleeve for vehicular air spring and vehicular air spring including the same

Abstract

To provide a sleeve for a vehicular air spring which achieves improvement of spring characteristics and rigidity without having a complicated reinforced fiber step, and to provide a vehicle air spring including the same.SOLUTION: A sleeve for a vehicle air spring according to one embodiment of the invention includes at least an upper sleeve and a lower sleeve. An upper end circumferential portion of the upper sleeve is coupled to a top mount part, a lower end circumferential portion of the lower sleeve is coupled to a piston portion, and one of the upper sleeve and the lower sleeve may be formed to have thicknesses which are different between sections along a longitudinal direction.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a sleeve for an air spring for a vehicle and an air spring for a vehicle including the same, and more particularly to a sleeve for an air spring for a vehicle and an air spring for a vehicle including the same, which have improved spring characteristics and rigidity without a complicated reinforcing fiber process. [Background technology]

[0002] An automobile suspension is a device that exists between the body and the wheels, and connects these two rigid bodies using one or more links. It is supported in the vertical direction by springs and shock absorbers, and in other directions, it performs the function of mechanically harmonizing the relative movement between the body and the wheels by appropriately balancing high rigidity and flexibility.

[0003] Such a suspension must satisfy the following basic requirements: it must effectively block out irregular road inputs that occur while the vehicle is running, providing passengers with a comfortable ride; it must provide driving convenience by appropriately controlling the shaking of the vehicle body caused by the driver's driving actions and curvature of the road; and it must maintain an appropriate level of vertical load on the tire's contact surface when running on irregular road surfaces, ensuring maneuverability and stability of the vehicle when cornering, braking, and driving.

[0004] In order to satisfy these conditions, various types of suspensions have been developed and applied to vehicles. Recently, air suspensions that improve ride comfort by changing the volume of the sleeve that forms the air spring to change the air spring constant and automatically maintain the vehicle height by changing the amount of air are widely used in luxury passenger cars.

[0005] Since such sleeves are repeatedly deformed, they need to have excellent durability, but conventional sleeves have had difficulty in satisfying this requirement. For example, to improve durability, conventional rubber sleeves have had to undergo a complicated fiber-reinforced process to reinforce their rigidity, but this has led to a problem of a significant drop in the efficiency of sleeve manufacturing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 2,090,801 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a sleeve for a vehicle air spring, and an air spring for a vehicle including the same, which have improved spring characteristics and rigidity without a complicated reinforcing fiber process.

[0008] Also, the present invention provides a sleeve for a vehicle air spring, which allows easy stress management of the material through management of the expansion rate of the sleeve, and an air spring for a vehicle including the same.

[0009] Another object of the present invention is to provide a sleeve for an air spring for a vehicle, and an air spring for a vehicle including the same, which can improve product performance by improving design freedom.

[0010] In addition, the present invention provides a sleeve for an air spring for a vehicle, in which the sleeve is divided into a plurality of pieces and each piece is manufactured by injection molding, thereby improving the flowability of the injection molding during injection molding of each sleeve and improving the quality of the sleeve, and an air spring for a vehicle including the same. [Means for solving the problem]

[0011] A sleeve 500 for an air spring for a vehicle according to one embodiment of the present invention includes at least an upper sleeve 520 and a lower sleeve 540, 640, an upper circumferential portion 522 of the upper sleeve 520 is connected to a top mount portion, and a lower circumferential portion 544, 644 of the lower sleeve 540, 640 is connected to a piston portion, and one of the upper sleeve 520 and the lower sleeve 540, 640 may be formed to have different thicknesses in different sections along the longitudinal direction.

[0012] As an example, the thickness of the sleeve in the area where the rolling lobe is formed when the piston portion is at its maximum upward movement may be greater than the thickness of the sleeve in the area where the rolling lobe is formed when the piston portion is at its maximum downward movement.

[0013] As another example, the thickness of the sleeve in the area where the rolling lobe is formed when the piston portion rises to its maximum may be greater than the thickness of the sleeve in the area where the rolling lobe is formed when the vehicle is in a drivable state and the vehicle is stopped.

[0014] According to one embodiment of the present invention, the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 are arranged to overlap each other, and the thickness of the upper sleeve 520 and the thickness of the lower sleeve 540 in the overlapping area may be substantially the same or the inner sleeve of the overlapping sleeves may be thicker than the outer sleeve.

[0015] In addition, the sleeves formed to have different thicknesses may be configured to include at least a section in which the inner diameter is uniform in the longitudinal direction and a section in which the inner diameter decreases uniformly downward in the longitudinal direction. An inner diameter transition section connecting the section in which the inner diameter is uniform in the longitudinal direction and the section in which the inner diameter decreases uniformly downward in the longitudinal direction may be formed.

[0016] According to an embodiment of the present invention, the sleeves may be formed to have different thicknesses such that the sleeve has a maximum thickness in a region where a rolling lobe is formed when the piston portion is raised to the maximum.

[0017] Also, the sleeves may be formed to have different thicknesses such that the sleeve has a minimum thickness in an area where a rolling lobe is formed when the vehicle is in a runnable state and the vehicle is stopped.

[0018] Also, the sleeves may be formed to have different thicknesses such that the sleeve has a minimum thickness in a region where a rolling lobe is formed when the piston portion is at its maximum downward movement.

[0019] The maximum thickness may be within a range of 3.0 to 7.0 mm, and the minimum thickness may be within a range of 1.0 to 4.0 mm.

[0020] According to an embodiment of the present invention, the sleeves formed to have different thicknesses may be lower sleeves 540 and 640 .

[0021] According to one embodiment of the present invention, the air spring for a vehicle may include sleeves 500, 600 for the air spring for a vehicle having the above-mentioned structure, a top mount portion to which upper circumferential portions 522, 622 of the upper sleeves 520, 620 are coupled, and a piston portion to which lower circumferential portions 544, 644 of the lower sleeves 540, 640 are coupled. Effect of the Invention

[0022] According to an embodiment of the present invention, a sleeve for an air spring for a vehicle has different thicknesses in different sections in the longitudinal direction, so that spring characteristics and rigidity can be improved at the same time without a complicated reinforcing fiber process.

[0023] In addition, by dividing the sleeve into several pieces and manufacturing each piece by injection molding, the flow of the injection molding is improved during the injection molding of each sleeve, improving the quality of the sleeve and improving the design freedom, thereby improving the performance of the product. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a perspective view of a sleeve according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the sleeve shown in FIG. [Diagram 3] 2 is a cross-sectional view of the sleeve shown in FIG. 1. [Figure 4] FIG. 13 is a perspective view of a sleeve according to yet another embodiment of the present invention. [Diagram 5] FIG. 5 is an exploded perspective view of the sleeve shown in FIG. 4. [Figure 6] 5 is a cross-sectional view of the sleeve shown in FIG. 4. [Figure 7] 6 is a cross-sectional view of the lower sleeve illustrating a change in thickness of the lower sleeve in the longitudinal direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention can be modified in various ways and can have various embodiments, and a specific embodiment will be described in detail with reference to the drawings. However, this is not intended to limit the present invention to a specific embodiment, and it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used for similar components. Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another component. For example, a first component may be named a second component, and similarly, the second component may be named a first component, without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated items or any item of multiple associated items. When a component is referred to as being "connected" or "connected" to another component, it should be understood that the other components may be directly connected or connected to the other components, but there may be other components in between. On the other hand, when a component is described as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between. The terms used in this application are merely used to describe a particular embodiment and are not intended to limit the present invention. The singular term includes the plural term unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. In addition, the terms "first" and "second" are used in this specification for the purpose of distinction only and should not be understood to indicate or predict any order or priority in any manner.Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention belongs. Terms as defined in commonly used dictionaries should be interpreted to have a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted in an ideal or overly formal sense unless expressly defined in this application. In addition, the term "about" should be understood in this specification to include the range of manufacturing tolerances in the art to which this invention belongs.

[0026] In the specification and claims, when a part includes a certain element, this does not mean excluding other elements, but may further include other elements, unless otherwise specified. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0027] The air spring may be disposed between the top mount portion and the piston portion and may be embodied to act as a spring. For example, the air spring may include a housing and a sleeve.

[0028] According to one embodiment of the present invention, one end of the sleeve may be hermetically fixed to the top mount portion and the other end may be hermetically fixed to the piston portion. The sleeve may be surrounded by a housing.

[0029] For example, the sleeve is an air bag whose volume can change with the up and down movement of the piston. That is, the sleeve, which has a certain pressure inside, changes its volume with the up and down movement, and the internal pressure changes accordingly, acting as a spring.

[0030] According to one embodiment of the present invention, one end of the sleeve may be hermetically fixed to the top mount portion, and the other end may be hermetically fixed to the inner surface of the piston portion. The sleeve may be surrounded by a housing. When the piston portion moves axially upward relative to the piston portion, the bent portion of the sleeve, i.e., the portion where the rolling lobe is formed, may be rolled together with the piston portion to form a circle. As a result, the air in the sleeve is compressed, and the air spring operates as a spring.

[0031] Fig. 1 is a perspective view of a sleeve according to an embodiment of the present invention. The sleeve shown in Fig. 1 is a sleeve before it is attached to a top mount portion and a piston portion and a lobe is formed. Fig. 2 is an exploded perspective view of the sleeve shown in Fig. 1. Fig. 3 is a cross-sectional view of the sleeve shown in Fig. 1.

[0032] 1 to 3, a sleeve 500 for an air spring for a vehicle according to an embodiment of the present invention may be generally cylindrical, for example, and may include at least an upper sleeve 520 and a lower sleeve 540. An upper circumferential portion 522 of the upper sleeve 520 may be coupled to a top mount portion, and a lower circumferential portion 524 of the upper sleeve 520 may be coupled to an upper circumferential portion 542 of the lower sleeve 540. A lower circumferential portion 544 of the lower sleeve 540 is coupled to a piston portion.

[0033] In FIG. 1, the lower sleeve 540 of the upper sleeve 520 and the lower sleeve 540 is configured to include a region that forms a rolling lobe, but the upper sleeve 520 may be configured to include a region that forms a rolling lobe.

[0034] In the present invention, the sleeve 500 can be manufactured separately into a sleeve including a region forming a rolling lobe and a sleeve not including such a region. Accordingly, while satisfying the high rigidity required for the sleeve 500, the design freedom of the sleeve 500 is improved and the manufacturing efficiency of the sleeve can be improved.

[0035] For example, the upper sleeve 520 and the lower sleeve 540 may be made of the same material, but the sleeve that does not include the area that forms the rolling lobe may be made of a material that is stiffer than the rest of the sleeve, because a stiffer material may not be suitable for forming a rolling lobe.

[0036] Additionally, the upper sleeve 520 and the lower sleeve 540 may be manufactured by injection molding using a thermoplastic elastomer (TPE) material.

[0037] Thermoplastic elastomer materials can be molded by injection or extrusion blow molding like ordinary plastic materials, and can be reused, but they also have the properties of an elastomer.

[0038] According to one embodiment of the present invention, the upper sleeve 520 and the lower sleeve 540 are each independently manufactured by injection molding using a thermoplastic elastomer material, which improves the design flexibility of the upper sleeve 520 and the lower sleeve 540. For example, the sleeve including the region where the rolling lobe is formed can be designed to have excellent stiffness and spring characteristics by having a thickness variation in the longitudinal direction (as described below).

[0039] In addition, the flowability of the sleeve 500 during injection molding can be improved. The sleeve 500 according to an embodiment of the present invention can be designed to have different inner diameters in the longitudinal direction, but this can cause poor flowability during injection molding when a single sleeve is injection molded, which can make quality control of the sleeve difficult. In the present invention, the sleeve 500 is manufactured separately into the upper sleeve 520 and the lower sleeve 540, and the flowability during injection molding can be improved.

[0040] According to one embodiment of the present invention, the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 may be attached to the upper circumferential portion 542 of the lower sleeve 540 by welding the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540.

[0041] For example, the lower circumferential portion 524 of the upper sleeve 520 can be attached to the upper circumferential portion 542 of the lower sleeve 540 by positioning the upper sleeve 520 and the lower sleeve 540 so that the ends of the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 face each other (butt joint) and welding the facing portions.

[0042] More preferably, according to one embodiment of the present invention, the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 may be disposed to overlap each other, as shown in Fig. 3. The overlapping area may be welded to attach the lower circumferential portion 524 of the upper sleeve 520 to the upper circumferential portion 542 of the lower sleeve 540.

[0043] In addition, for such welding, one of the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 may have a step portion formed in the circumferential direction for positioning the remaining sleeve. As an example, FIG. 3 shows a step portion 546 formed in the lower circumferential portion 524 of the upper sleeve 520 in the circumferential direction.

[0044] According to an embodiment of the present invention, the upper sleeve 520 and the lower sleeve 540 may be joined by laser welding in the overlapping region. That is, the lower end circumferential portion 524 of the upper sleeve 520 and the upper end circumferential portion 542 of the lower sleeve 540 may be joined by laser welding along the circumferential direction. To this end, as an example, the inner sleeve may include a laser energy absorbing material, and the outer sleeve may include a laser transmissible material. As an example of a laser energy absorbing material, the inner sleeve may include carbon black.

[0045] Additionally, according to one embodiment of the present invention, each of the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 may be configured to include an outwardly extending flange.

[0046] The flanges may be placed in opposing contact with one another and the flanges may be welded to attach the lower circumferential portion 524 of the upper sleeve 520 to the upper circumferential portion 542 of the lower sleeve 540 .

[0047] Fig. 4 is a perspective view of a sleeve according to yet another embodiment of the present invention, Fig. 5 is an exploded perspective view of the sleeve shown in Fig. 4, and Fig. 6 is a cross-sectional view of the sleeve shown in Fig. 4.

[0048] 4 to 6, the sleeve 600 according to an embodiment of the present invention may further include a middle sleeve 660 interposed between the upper sleeve 620 and the lower sleeve 640. A lower circumferential portion 624 of the upper sleeve 620 may be coupled to an upper circumferential portion 662 of the middle sleeve 660, and a lower circumferential portion 664 of the middle sleeve 660 may be coupled to an upper circumferential portion 642 of the lower sleeve 640. A lower circumferential portion 644 of the lower sleeve 640 may be coupled to the piston portion. An upper circumferential portion 622 of the upper sleeve 620 may be coupled to the top mount portion.

[0049] As an example, the lower end circumferential portion 624 of the upper sleeve 620 and the upper end circumferential portion 662 of the intermediate sleeve 660 may be welded together to attach the lower end circumferential portion 624 of the upper sleeve 620 to the upper end circumferential portion 662 of the intermediate sleeve 660, and the lower end circumferential portion 664 of the intermediate sleeve 660 may be welded together to attach the lower end circumferential portion 664 of the intermediate sleeve 660 to the upper end circumferential portion 642 of the lower sleeve 640.

[0050] For example, the lower circumferential portion 624 of the upper sleeve 620 can be attached to the upper circumferential portion 662 of the intermediate sleeve 660 by positioning the upper sleeve 620 and the intermediate sleeve 660 so that the ends of the lower circumferential portion 624 of the upper sleeve 620 and the upper circumferential portion 662 of the intermediate sleeve 660 face each other and welding the opposing portions.

[0051] Through this, the sleeve 600 of the present invention can have a further improved degree of freedom in design. For example, the upper sleeve 620 and the lower sleeve 640 can be made of different materials independently, but in a structure in which the upper sleeve 620 and the lower sleeve 640 are joined together, the degree of freedom in selecting materials may be reduced due to the joining. On the other hand, when the intermediate sleeve 660 is interposed between the upper sleeve 620 and the lower sleeve 640, even if materials that are difficult to join are selected for the upper sleeve 620 and the lower sleeve 640, the difficulty in joining can be resolved through the intermediate sleeve 660.

[0052] More preferably, according to an embodiment of the present invention, as shown in Fig. 6, the lower circumferential portion 624 of the upper sleeve 620 and the upper circumferential portion 662 of the middle sleeve 660 may be arranged to overlap each other, and the lower circumferential portion 664 of the middle sleeve 660 and the upper circumferential portion 642 of the lower sleeve 640 may be arranged to overlap each other. In this case, additionally, one of the upper circumferential portion 662 of the middle sleeve 660 and the lower circumferential portion 624 of the upper sleeve 620 may have a step portion 666 for positioning formed along the circumferential direction, and one of the lower circumferential portion 664 of the middle sleeve 660 and the upper circumferential portion 642 of the lower sleeve 640 may have a step portion 668 for positioning formed along the circumferential direction. Fig. 6 shows an example in which the step portions 666, 668 are formed on the upper circumferential portion 662 of the middle sleeve 660 and the lower circumferential portion 664 of the middle sleeve 660.

[0053] The lower end circumferential portion 624 of the upper sleeve 620 and the upper end circumferential portion 662 of the intermediate sleeve 660 are arranged to overlap each other, and the overlapping region is welded, so that the lower end circumferential portion 624 of the upper sleeve 620 can be attached to the upper end circumferential portion 662 of the intermediate sleeve 660. Similarly, the lower end circumferential portion 664 of the intermediate sleeve 660 and the upper end circumferential portion 642 of the lower sleeve 640 are arranged to overlap each other, and the overlapping region is welded, so that the lower end circumferential portion 664 of the intermediate sleeve 660 can be attached to the upper end circumferential portion 642 of the lower sleeve 640. In FIG. 6, as an example, the intermediate sleeve 660 is arranged on the inside in the overlapping region, and the upper sleeve 620 to the lower sleeve 640 are arranged on the outside. In such an arrangement, where the middle sleeve 660 and the upper sleeve 620 or the lower sleeve 640 are laser welded together, the middle sleeve 660 may be made of a laser energy absorbing material (e.g., carbon black) and the upper sleeve 620 and the lower sleeve 640 may be made of a laser transmissive material.

[0054] Additionally, according to one embodiment of the present invention, the lower circumferential portion 624 of the upper sleeve 620 and the upper circumferential portion 662 of the middle sleeve 660 may each be configured to include an outwardly extending flange. The flanges may be disposed in opposing contact with one another, and the lower circumferential portion 624 of the upper sleeve 620 may be attached to the upper circumferential portion 662 of the middle sleeve 660 by welding the flanges.

[0055] Similarly, the lower circumferential portion 664 of the middle sleeve 660 and the upper circumferential portion 642 of the lower sleeve 640 may each be configured to include an outwardly extending flange. The flanges may be disposed in opposing contact with one another, and the lower circumferential portion 664 of the middle sleeve 660 may be attached to the upper circumferential portion 642 of the lower sleeve 640 by welding the flanges.

[0056] Fig. 7 is a cross-sectional view of the lower sleeve for explaining thickness change in the longitudinal direction of the lower sleeve. The configuration of the lower sleeve as shown in Fig. 7 can be applied to both the sleeve composed of the upper sleeve and the lower sleeve in Fig. 1 and the sleeve composed of the upper sleeve, the middle sleeve, and the lower sleeve in Fig. 4. In addition, although the configuration of thickness change is described below mainly for the lower sleeve, it should be understood that such a configuration of thickness change can also be applied to the upper sleeve.

[0057] The sleeve (particularly the lower sleeve) according to the present invention acts as an air bag whose volume can change with the up and down movement of the piston. That is, the sleeve, which has a certain pressure inside, changes its volume with the up and down movement of the piston, and the internal pressure changes accordingly.

[0058] For example, when the piston part is fully jounced, the sleeve has a minimum volume, the internal pressure increases accordingly, and the load on the area where the rolling lobe is formed increases. On the other hand, when the piston part is fully rebounded, the sleeve has a maximum volume, the internal pressure decreases accordingly, and the load on the area where the rolling lobe is formed decreases.

[0059] On the other hand, the sleeve is required to have rigidity for durability, but at the same time, it is required to have spring characteristics.

[0060] In order to simultaneously satisfy both durability and spring characteristics, the lower sleeves 540 and 640 according to an embodiment of the present invention may be formed to have different thicknesses in different sections along the longitudinal direction.

[0061] For example, the thickness of the sleeve in the region where the rolling lobe is formed when the piston portion rises to its maximum may be greater than the thickness of the sleeve in the region where the rolling lobe is formed when the piston portion falls to its maximum, or the thickness of the sleeve in the region where the rolling lobe is formed when the piston portion rises to its maximum may be greater than the thickness of the sleeve in the region where the rolling lobe is formed when the vehicle is in a drivable state and the vehicle is stopped (when the vehicle is in the normal position).

[0062] Accordingly, the durability of the sleeve can be improved by increasing the thickness of the sleeve in areas where a large load is applied, and at the same time, the spring characteristics of the air spring can be ensured by decreasing the thickness of the sleeve in areas where a relatively small load is applied.

[0063] According to an embodiment of the present invention, the lower sleeve 540, 640 may be formed to have a maximum thickness in a region where the rolling lobe is formed when the piston portion is fully raised. For example, the maximum thickness may be within a range of 3.0 to 7.0 mm.

[0064] Also, according to an embodiment of the present invention, the lower sleeve 540, 640 may be formed to have a minimum thickness in an area where a rolling lobe is formed when the vehicle is in a runnable state and the vehicle is stopped. Also, the lower sleeve 540, 640 may be formed to have a minimum thickness in an area where a rolling lobe is formed when the piston part is fully lowered. Additionally, in order to impart more spring characteristics, the lower sleeve 540, 640 may be formed to have a minimum thickness over the entire area where a rolling lobe is formed when the piston part is fully lowered and the entire area where a rolling lobe is formed when the vehicle is in a runnable state and the vehicle is stopped. As an example, the minimum thickness may be within a range of 1.0 to 4.0 mm.

[0065] According to one embodiment of the present invention, the lower circumferential portion 524 of the upper sleeve 520 and the upper circumferential portion 542 of the lower sleeve 540 (as described above) may be positioned to overlap one another, and the overlapped area may be attached by laser welding.

[0066] Considering this, in the present invention, the thickness of the upper sleeve 520 and the thickness of the lower sleeve 540 may be configured not to change along the longitudinal direction in the overlapping region. When applying laser welding, the same energy must be delivered to the overlapping portion, but if the thickness changes along the longitudinal direction, it is difficult to deliver the same energy, which makes the welding conditions complicated. As an example, the overlapping region may be 5 mm or more in the longitudinal direction.

[0067] In the overlapping region, the thickness of the upper sleeve 520 and the thickness of the lower sleeve 540 may be configured to be the same as each other, or the innermost sleeve of the overlapping sleeves may be thicker than the outermost sleeve.

[0068] As an example having the above-mentioned configuration, the lower sleeve 540, 640 may be configured to include, from top to bottom, a first section having a constant inner diameter in the longitudinal direction, a second section having a uniform inner diameter decreasing in the longitudinal direction, a third section having a uniform inner diameter in the longitudinal direction, a fourth section having a uniform inner diameter decreasing in the longitudinal direction, and a fifth section having a uniform inner diameter in the longitudinal direction (as shown in FIG. 7). In addition, inner diameter transition sections connecting the sections may be formed between each section.

[0069] In the first section, the sleeve has a substantially uniform thickness along its length, which may be, for example, about 3 mm, and in the second section, which may include a region where the rolling lobe is formed when the piston portion is at its maximum elevation, the thickness of the second section is the maximum, which may be, for example, about 3.5 mm.

[0070] The third section, the fourth section, and the inner diameter transition section connecting the third section and the fourth section may include a region where a rolling lobe is formed when the piston portion descends to its maximum extent and a region where a rolling lobe is formed when the vehicle is in a drivable state and the vehicle is stopped, and the third section, the fourth section, and the inner diameter transition section connecting the third section and the fourth section may have a minimum thickness, for example, about 2.5 mm. [Explanation of symbols]

[0071] 500, 600: Sleeve 520: Upper sleeve 540: Lower sleeve 660: Intermediate sleeve

Claims

1. A sleeve (500) for a vehicle air spring, The sleeve includes at least an upper sleeve (520) and a lower sleeve (540, 640); An upper end circumferential portion (522) of the upper sleeve (520) is connected to a top mount portion, A lower end circumferential portion (544, 644) of the lower sleeve (540, 640) is connected to the piston portion, The sleeve for an air spring for a vehicle is formed such that one of the upper sleeve (520) and the lower sleeve (540, 640) has a different thickness from the other in each section along a longitudinal direction.

2. 2. A sleeve for a vehicle air spring as claimed in claim 1, wherein the thickness of the sleeve in a region where a rolling lobe is formed when the piston portion is at its maximum upward movement is greater than the thickness of the sleeve in a region where a rolling lobe is formed when the piston portion is at its maximum downward movement.

3. 2. A sleeve for a vehicle air spring as described in claim 1, wherein the thickness of the sleeve in a region where a rolling lobe is formed when the piston portion rises to its maximum is greater than the thickness of the sleeve in a region where a rolling lobe is formed when the vehicle is in a drivable state and the vehicle is stopped.

4. a lower end circumferential portion (524) of the upper sleeve (520) and an upper end circumferential portion (542) of the lower sleeve (540) are arranged to overlap each other; 2. A sleeve for a vehicle air spring as described in claim 1, wherein the thickness of the upper sleeve (520) and the thickness of the lower sleeve (540) are substantially the same in the overlapping region or the sleeve disposed on the inside of the overlapping sleeves is thicker than the sleeve disposed on the outside.

5. 2. The sleeve for a vehicle air spring as claimed in claim 1, wherein the sleeves formed to have different thicknesses are configured to include at least a section in which the inner diameter is the same in the longitudinal direction and a section in which the inner diameter decreases uniformly downward in the longitudinal direction.

6. 6. The sleeve for a vehicle air spring as claimed in claim 5, wherein an inner diameter transition section is formed between a section having a constant inner diameter in the longitudinal direction and a section in which the inner diameter decreases uniformly downward in the longitudinal direction, connecting both sections.

7. 2. The sleeve for a vehicle air spring as claimed in claim 1, wherein the sleeve is formed to have different thicknesses such that the sleeve has a maximum thickness in a region where a rolling lobe is formed when the piston portion rises to a maximum.

8. 2. The sleeve for a vehicle air spring as claimed in claim 1, wherein the sleeve is formed to have the different thicknesses so as to have a minimum thickness in an area where a rolling lobe is formed when the vehicle is in a runnable state and the vehicle is stopped.

9. 2. The sleeve for a vehicle air spring as claimed in claim 1, wherein the sleeve is formed to have different thicknesses such that the sleeve has a minimum thickness in a region where a rolling lobe is formed when the piston portion is at its maximum downward movement.

10. 8. A sleeve for a vehicle air spring as claimed in claim 7, wherein said maximum thickness is within the range of 3.0 to 7.0 mm.

11. 9. A sleeve for a vehicle air spring as claimed in claim 8, wherein said minimum thickness is within the range of 1.0 to 4.0 mm.

12. 2. The sleeve for a vehicle air spring according to claim 1, wherein the sleeve formed to have different thicknesses is the lower sleeve (540, 640).

13. A sleeve (500, 600) for a vehicle air spring according to any one of claims 1 to 12, a top mount portion to which the upper end circumferential portion (522, 622) of the upper sleeve (520, 620) is attached; An air spring for a vehicle, comprising a piston portion to which the lower end circumferential portion (544, 644) of the lower sleeve (540, 640) is attached.

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