leaf spring

Abstract

A leaf spring may include: an upper plate provided with an arc-shaped portion, which is integrally formed on both ends thereof, respectively, for forming a spring eyelet; a lower plate, which is positioned to overlap with the lower side of the upper plate and provided with an arc-shaped portion, which is integrally formed on both ends thereof and faces the arc-shaped portion of the upper plate, to form the spring eyelet; a clamping unit, which is arranged to prevent the two ends of the overlapping upper and lower plates from being separated from each other; and a central fastening unit, which is configured to fasten the central portion of the overlapping upper and lower plates.

Description

Technical Field

[0001] The present disclosure relates to a configuration of a leaf spring. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] By coupling both ends of the leaf spring to the vehicle frame and the center portion to the axle using U-bolts, the leaf spring can elastically support the axle relative to the vehicle frame and transmit driving force, braking force, and axle force to the vehicle body itself.

[0004] Conventional leaf springs are mainly made of steel materials, which are a factor in increasing the weight of vehicles. In recent years, technologies have been developed for reducing weight by using composite materials such as fiber reinforced plastics (FRP), thereby improving the fuel efficiency of vehicles.

[0005] The foregoing is merely intended to help understanding the background of the present disclosure, and is not intended to mean that the present disclosure falls within the scope of the relevant technologies known to those skilled in the art. Summary of the Invention

[0006] The present invention provides a leaf spring that is made of a composite material and can further reduce the weight of a vehicle with a simple configuration, and can effectively distribute stress in areas where stress may concentrate, thereby increasing its robustness and reducing manufacturing costs.

[0007] In a form of the present invention, the leaf spring may include: an upper plate provided with a first arc-shaped portion, which is integrally formed on both ends of the upper plate for forming a spring eyelet; a lower plate, which is placed to overlap with the lower side of the upper plate and is provided with a second arc-shaped portion, which is integrally formed on both ends thereof and is configured to face the first arc-shaped portion of the upper plate to form the spring eyelet; a clamping unit configured to prevent the two ends of the overlapping upper and lower plates from separating from each other; and a central fastening unit configured to fasten the central portion of the overlapping upper and lower plates.

[0008] In a form, a bush may be inserted into each of the spring holes formed by the first and second arc-shaped portions of the upper and lower plates.

[0009] The upper plate and the lower plate may be spaced apart from each other adjacent the bushing to form a first gap.

[0010] In a form, a recessed portion configured to form the first gap may be formed on at least one of the upper plate or the lower plate overlapping each other, and the recessed portion may be formed by pressing down a contact surface between the upper plate and the lower plate.

[0011] In another form, the size of the first gap may be adjusted by the diameter of a bushing inserted into the eyelet of the spring.

[0012] In other forms, the outer side of the first arc-shaped portion of the upper plate is configured to protrude upward, while the outer side of the second arc-shaped portion of the lower plate is configured to protrude downward.

[0013] The upper plate and the lower plate may be formed to have the same shape and may be symmetrically coupled to each other to form the spring eyelet.

[0014] The clamping unit may include: an upper piece, provided with an arcuate cross-sectional portion surrounding a first arcuate portion of the upper plate and flat portions extending from both sides of the arcuate cross-sectional portion of the upper piece; a lower piece, provided with an arcuate cross-sectional portion surrounding a second arcuate portion of the lower plate and flat portions extending from both sides of the arcuate cross-sectional portion of the lower piece; and a plurality of fasteners configured to pass through and fasten the upper piece and the lower piece respectively placed on the upper side and the lower side of the overlapping upper and lower plates.

[0015] The upper sheet and the lower sheet may be formed to have the same shape and may be symmetrically coupled to each other in a state of sandwiching the overlapped upper and lower plates.

[0016] In a state where the upper and lower pieces are placed on the upper and lower sides of the overlapping upper and lower plates, respectively, a second gap may be formed between the outer flat portions of the upper and lower pieces before the upper and lower pieces are fixed by a plurality of fasteners.

[0017] The plurality of fasteners may include: at least one first bolt passing through and fastening the inner flat portion of the upper piece, the upper plate, the lower plate, and the inner flat portion of the lower piece to reduce the first gap; and at least one second bolt passing through and fastening the outer flat portion of the upper piece and the outer flat portion of the lower piece to reduce the second gap.

[0018] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order that the present disclosure may be better understood, various forms thereof will now be described, given by way of example, with reference to the accompanying drawings, in which:

[0020] Figure 1 is a perspective view showing an assembled leaf spring;

[0021] Figure 2 yes Figure 1 Exploded perspective view of the middle leaf spring;

[0022] Figure 3 It is shown in detail Figure 1 a view of a portion of

[0023] Figure 4A yes Figure 3 a side view of a portion of;

[0024] Figure 4B yes Figure 4A an enlarged view of a portion of the

[0025] Figure 5 is a view exemplarily showing a state in which a leaf spring is applied to a vehicle.

[0026] The drawings described herein are for illustration purposes only and are not intended to obscure the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0027] The following description is merely exemplary in nature and is not intended to prevent the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0028] Hereinafter, a leaf spring according to an exemplary form of the present disclosure will be described with reference to the accompanying drawings.

[0029] Reference Figures 1 to 5 , a leaf spring according to the form of the present disclosure includes: an upper plate 3, provided with an arc-shaped portion 1, which is integrally formed on its two end portions, respectively, for forming a spring eyelet E; a lower plate 5, which is placed to overlap with the lower side of the upper plate 3 and is provided with an arc-shaped portion 1 integrally formed on its two end portions, respectively, and faces the arc-shaped portion 1 of the upper plate 3 to form the spring eyelet E; a clamping unit 7, which is arranged to prevent the two end portions of the overlapping upper plate 3 and lower plate 5 from being separated from each other; and a central fastening unit 9, which is configured to fasten the central portion of the overlapping upper plate 3 and lower plate 5.

[0030] In other words, in this form, the upper plate 3 and the lower plate 5 made of composite material are integrated together by means of the clamping unit 7 and the central fastening unit 9, are mounted on the frame 11 through the clamping unit 7, and are coupled to the axle 13 through the central fastening unit 9, thereby performing the function of enabling the axle 13 to elastically support the frame 11.

[0031] For reference, the front spring eyelet E of the leaf spring is mounted to the frame 11 via a mounting bracket 15, the rear spring eyelet E is mounted to the frame 11 via a shackle 17, and the central fastening unit 9 includes an upper body 19, a lower body 21 and a U-bolt 23 that surrounds the upper body 19 and the lower body 21 and is fastened to the axle 13.

[0032] In this form, the bushing 25 is inserted into each spring eyelet E formed by the arc-shaped portions 1 at both ends of the upper plate 3 and the lower plate 5 .

[0033] That is, the bushing 25 may be made of a durable material and formed into a tubular shape to maintain a state in which the leaf spring is firmly and durably coupled to the mounting bracket 15 and the shackle 17 through the pin.

[0034] The upper plate 3 and the lower plate 5 surrounding the bushing 25 are spaced apart from each other to form a first gap G1 .

[0035] The first gap G1 may be formed by a recessed portion 27 formed on at least one of the upper plate 3 or the lower plate 5 that overlap each other, and the recessed portion 27 is formed by pressing down the contact surface between the upper plate 3 and the lower plate 5. Figure 4A and Figure 4B As shown, the contact surface may be the lower side surface of the upper plate 3 facing the lower plate 5 near the spring eyelet E.

[0036] That is, the first gap G1 can be formed by forming a recessed portion 27 (for example, a groove or a slot) on the lower side of the two end portions of the upper plate 3, or by forming a recessed portion 27 on the upper side of the two end portions of the lower plate 5, or by forming a recessed portion 27 on the lower side of the two end portions of the upper plate 3 and on the upper side of the two end portions of the lower plate 5.

[0037] As a reference, Figure 4A and Figure 4B The first gap G1 formed by the recessed portions 27 formed on the lower sides of both end portions of the upper plate 3 is merely exemplarily shown.

[0038] On the other hand, the size of the first gap G1 may be configured to be adjusted by the diameter of the bushing 25 inserted into the spring eyelet E.

[0039] That is, in a state where the spring eyelet E is constant, when the diameter of the bushing 25 increases, the size of the first gap G1 increases, and when the diameter of the bushing 25 decreases, the size of the first gap G1 decreases.

[0040] Therefore, the first gap G1 can be formed simply by inserting the bushing 25 , which is slightly larger than the spring eyelet E, into the spring eyelet E in a state where the recessed portion 27 as described above is not provided.

[0041] On the other hand, the upper plate 3 is configured so that the outer portion of the arc-shaped portion 1 thereof protrudes upward, and the lower plate 5 is configured so that the outer portion of the arc-shaped portion 1 thereof protrudes downward.

[0042] In this way, the configuration in which the outer sides of the arc-shaped portions 1 of the upper plate 3 and the lower plate 5 protrude upward and downward enables the upper plate 3 and the lower plate 5 to be formed to have a relatively thin thickness, while fully ensuring the strength of the portion formed by the spring eyelet E, and enables the ends of the upper plate 3 and the lower plate 5 to be maintained in a more firmly combined state through the clamping unit 7 described later.

[0043] The upper plate 3 and the lower plate 5 may be configured to have the same shape and be symmetrically coupled to each other so as to form the spring eyelet E.

[0044] That is, although the upper plate 3 and the lower plate 5 can be configured as separate components and overlap each other to constitute the leaf spring of the present disclosure, two components having substantially the same shape are manufactured to use one of the components as the upper plate 3 and the other as the lower plate 5, and thus the number of components required for management can be reduced, ease of assembly can be ensured, and ultimately the cost of manufacturing the leaf spring can be reduced.

[0045] The clamping unit 7 includes: an upper piece 33, which is provided with an arcuate cross-sectional portion 29 surrounding the arcuate portion 1 of the upper plate 3 and flat portions 31 extending from both sides of the arcuate cross-sectional portion 29; a lower piece 35, which is provided with an arcuate cross-sectional portion 29 surrounding the arcuate portion 1 of the lower plate 5 and flat portions 31 extending from both sides of the arcuate cross-sectional portion 29; and a plurality of fastening devices that pass through and fasten the upper piece 33 and the lower piece 35 respectively placed on the upper and lower sides of the overlapping upper plates 3 and lower plates 5.

[0046] That is, the fastening device can ensure the coupled state of the upper piece 33 and the lower piece 35 in a state where the upper piece 33 and the lower piece 35 overlap the upper and lower sides of both end portions of the overlapping upper plate 3 and the lower plate 5, respectively.

[0047] The upper piece 33 and the lower piece 35 may be formed to have the same shape and may be symmetrically coupled to each other in a state of sandwiching the overlapped upper plate 3 and lower plate 5 .

[0048] That is, although separate components having slightly different shapes from each other can be used as the upper piece 33 and the lower piece 35, by forming the above-mentioned thin sheets to have the same shape, as in the present form, the number of components required for management can be reduced, and ease of assembly can be ensured, and ultimately the cost of manufacturing the leaf spring can be reduced.

[0049] In addition, the upper piece 33 and the lower piece 35 can be mass-produced by simply punching a flat plate, and thus the cost of manufacturing the leaf spring of the present disclosure can be further reduced.

[0050] On the other hand, when the upper piece 33 and the lower piece 35 are respectively placed on the upper and lower sides of the overlapping upper plates 3 and lower plates 5, a second gap G2 is formed between the outer flat portion 31 of the upper piece 33 and the outer flat portion 31 of the lower piece 35 before the upper piece and the lower piece are fastened and fixed by the device.

[0051] The fastening device includes at least one first bolt 37, which passes through and fastens the inner flat portion 31 of the upper piece 33, the upper plate 3, the lower plate 5 and the inner flat portion 31 of the lower piece 35 to reduce the first gap G1; and at least one second bolt 39, which passes through and fastens the outer flat portion 31 of the upper piece 33 and the outer flat portion 31 of the lower piece 35 to reduce the second gap G2.

[0052] For reference, the “inner flat portion” refers to the flat portion 31 facing the central fastening unit 9 , and the “outer flat portion” refers to the flat portion 31 opposite to the inner flat portion with respect to the arc-shaped cross-sectional portion 29 .

[0053] Of course, the nuts 41 are coupled to the first and second bolts 37, 39, respectively, to generate a coupling force. At this time, the first and second gaps G1, G2, respectively, counteract the forces applied by the first and second bolts 37, 39, together with the nuts 41, in the direction of reducing the distance between the upper plate 33 and the lower plate 35. Therefore, these nuts 41 act in the direction in which the elastic force of the upper and lower plates 3, 5 widens the gap between the upper and lower plates 3, 5. As a result, the friction between the heads of the first and second bolts 37, 39 and the upper plate 33, and between the nuts 41 and the lower plate 35, can be sufficiently ensured, enabling the first and second bolts 37, 39 to be securely fastened.

[0054] In addition, if Figure 3 As shown in Figure 4, the arc-shaped cross-sectional portion 29 of the upper piece 33 and the arc-shaped cross-sectional portion 29 of the lower piece 35 are coupled to each other by the first bolt 37 and the second bolt 39 respectively when the two portions 29 surround the arc-shaped portion 1 of the upper plate 3 and the arc-shaped portion 1 of the lower plate 5. Therefore, the movement of the upper piece 33 and the lower piece 35 relative to the upper plate 3 and the lower plate 5 is structurally suppressed, and the uniformly distributed stress generated at the ends of the upper plate 3 and the lower plate 5 can form a coupling state that maintains a stronger and more stable state.

[0055] The leaf spring made of a composite material of the present disclosure can further reduce the weight of a vehicle with a simple configuration and effectively distribute stress in areas where stress may be concentrated, thereby increasing its robustness and reducing manufacturing costs.

[0056] Although exemplary forms of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure.

Claims

1. A leaf spring comprising: An upper plate is provided with a first arc-shaped portion, wherein the first arc-shaped portion is integrally formed on both ends of the upper plate and is used to form a spring eyelet; a lower plate positioned to overlap with a lower side of the upper plate and provided with second arc-shaped portions, the second arc-shaped portions being integrally formed on both end portions of the lower plate, respectively, and configured to face the first arc-shaped portion of the upper plate to form the spring eyelet; a clamping unit configured to prevent both end portions of the overlapped upper plate and the lower plate from being separated from each other; as well as a central fastening unit configured to fasten central portions of the overlapped upper and lower plates, wherein a bushing is inserted into each of the spring holes formed by the first arc-shaped portion of the upper plate and the second arc-shaped portion of the lower plate; wherein the upper plate and the lower plate are spaced apart from each other to form a first gap near the bushing; and A recessed portion is formed on at least one of the upper plate and the lower plate that overlap each other, the recessed portion being configured to form the first gap, and the recessed portion is formed by pressing down a contact surface between the upper plate and the lower plate.

2. The leaf spring according to claim 1, wherein The size of the first gap is adjusted by the diameter of the bushing inserted into the corresponding spring eyelet.

3. The leaf spring according to claim 1, wherein An outer side of the first arc-shaped portion of the upper plate is configured to protrude upward, and an outer side of the second arc-shaped portion of the lower plate is configured to protrude downward.

4. The leaf spring according to claim 3, wherein The upper plate and the lower plate are formed to have the same shape and are symmetrically coupled to each other to form the spring eyelet.

5. The leaf spring according to claim 3, wherein Each of the clamping units comprises: an upper piece provided with an arcuate cross-sectional portion surrounding the first arcuate portion of the upper plate and flat portions extending from both sides of the arcuate cross-sectional portion of the upper piece; a lower piece provided with an arc-shaped cross-sectional portion surrounding the second arc-shaped portion of the lower plate and flat portions extending from both sides of the arc-shaped cross-sectional portion of the lower piece; and A plurality of fasteners are configured to pass through and fasten the upper and lower sheets respectively placed on the upper and lower sides of the overlapped upper and lower sheets.

6. The leaf spring according to claim 5, wherein The upper sheet and the lower sheet are formed to have the same shape and are symmetrically coupled to each other in a state where the overlapped upper plate and the lower plate are sandwiched therebetween.

7. The leaf spring according to claim 5, wherein In a state where the upper piece and the lower piece are placed on the upper and lower sides of the overlapping upper and lower plates, respectively, a second gap is formed between the outer flat portion of the upper piece and the outer flat portion of the lower piece before the upper piece and the lower piece are fixed by the plurality of fasteners.

8. The leaf spring according to claim 7, wherein The plurality of fasteners include: at least one first bolt configured to pass through and tighten the inner flat portion of the upper piece, the upper plate, the lower plate, and the inner flat portion of the lower piece so as to reduce the first gap; and At least one second bolt is configured to pass through and tighten the outer flat portion of the upper piece and the outer flat portion of the lower piece to reduce the second gap.

Images