3-link mechanism for reducing sideways movement of solid AXLE-coil spring suspension

Abstract

At present, most vehicles using solid axle-coil spring suspension use Panhard rod in controlling the sideways movement in the form of a single link with a fixed length aligned horizontally in parallel with a solid axle. It is linked to a chassis at one end and linked to the solid axle at the other end. Upon the solid axle moving vertically on rough road surface, the sideways movement follows because of the Panhard rod's fixed length. A characteristic 3-link mechanism, therefore, compensates for the Panhard rod's fixed length according to solid axle's vertical movement, reducing the solid axle's sideways movement or controlling the solid axle in nearly straight-line vertical movement. In addition, the 3-link mechanism has a roll center in a position lower than Panhard rod.

Description

[0001] 3-LINK MECHANISM FOR REDUCING SIDEWAYS MOVEMENT OF SOLID AXLE¬

[0002] COIL SPRING SUSPENSION

[0003] Field of the Invention

[0004] This invention relates to automotive engineering as regards sideways movement control links for solid axle-coil spring suspensions.

[0005] Background of the Invention

[0006] Most vehicles with solid axle-coil spring suspension usually use Panhard rod in control of sideways movement as invented by Panhard automobile company in the early 20s. Panhard rod is a single link with a fixed length aligned horizontally or nearly in parallel with a solid axle. It is linked to a chassis at one end and the solid axle at the other end in the form of rotational axis. Advantages are that it is simple and low-cost while a disadvantage is that the solid axle has sideways movement as it moves vertically on rough road surface as disclosed in a US patent publication number US5458359, entitled “Missing link swivel for four-link rigid axle suspensions”.

[0007] Afterwards, an invention was developed that was called Watt’s linkage, which was an application based on Watt steam engine in 1784, comprising 3 linked bars. The 2 outer bars had the same length; each of them had one end linked to a chassis and the other end linked with the middle bar in the form of rotational axis. The middle bar was much shorter and linked with the outer ones at both ends, and its body was linked to a solid axle in the form of rotational axis, hence called four-bar linkage, which had an advantage in that it eradicated sideways movement of the solid axle and a disadvantage in that the solid axle had less vertical movement distance than that of Panhard rod as disclosed in a US patent publication number US 10639952B2, entitled “Vehicle suspension”, and a US patent publication number US 20200393042A1, entitled “Control-linkage assembly for a differential of a vehicle and an axle assembly for a vehicle”.

[0008] In addition, there is another invention that helps reduce the sideways movement of solid axle that is an application based on Scott Russel linkage, which comprises 2 linked bars. The long bar having a length greater than the short one, is linked to a chassis at one end and is linked to a solid axle at the other end in the form of rotational axis. The short bar has one end linked at the body of the long one and the other end linked to the solid axle in the form of rotational axis. An advantage is that it helps reduce the sideways movement of the solid axle partly while a disadvantage is that the solid axle has considerably less vertical movement distance than that of Panhard rod as disclosed in a US patent publication number US5445404, entitled “Axle beam type suspension arrangement for automotive vehicle”.

[0009] It can be seen that the prior inventions contain claims on the linkage that helps reduce the sideways movement, with different advantages and disadvantages. Based on these, an invention has further been developed that is called the 3-link mechanism, which has advantages in that it helps reduce the sideways movement of solid axle almost entirely, and the solid axle has equivalent vertical movement distance to and a roll center (RC) lower than that of Panhard rod. Disadvantages are the costliness and durability.

[0010] Summary of the Invention

[0011] This invention is the 3-link mechanism for solid axle-coil spring suspension, comprising linked main parts, called a lower link, an upper link and a compensation link. There is a linkage of individual components.

[0012] The invention relating to this 3-link mechanism intends to help reduce the sideways movement of solid axle-coil spring suspension as vehicle moves on rough road surface as caused by the fixed length of the Panhard rod, using the characteristic 3-link mechanism for a compensation of the Panhard rod’s fixed length, controlling the solid axle in nearly straight-line vertical movement.

[0013] Detailed Description of the Invention

[0014] Mostly vehicles using the solid axle-coil spring suspension usually use the Panhard rod for controlling the sideways movement in the form of a single link with a fixed length aligned horizontally or nearly in parallel with the solid axle. It is linked to a chassis at one end and linked to the solid axle at the other end in the form of rotational axis. Upon the solid axle moving vertically on rough road surface, the sideways movement follows because of the Panhard rod’s fixed length. Compensation by the characteristic 3-link mechanism for the Panhard rod’s fixed length according to the solid axle’s vertical movement, therefore, reduce the solid axle’s sideways movement or control of the solid axle in nearly straight-line vertical movement.

[0015] The 3-link mechanism according to FIGs. 1, 2 and 3 illustrates in the event that a compensation link (3) is on the right side which can be flipped on the left side.

[0016] The 3-link mechanism according to FIGs. 1, 2 and 3 consists of 1. a lower link (1), 2. an upper link (2), and 3. a compensation link (3). The explanation of linkage between 3 links refers to 3-link mechanism where the lower link (1) aligns horizontally or nearly as shown in FIG. IB.

[0017] Each component is characterized in that:

[0018] A lower link (1) aligned horizontally or nearly, having a length greater than the upper link (2). One end of the link is linked in a form of pivot or rotational axis (5) to a chassis (4) and other end linked in a form of pivot or rotational axis (5) to a body of a compensation link (3).

[0019] An upper link (2) aligned horizontally or nearly, having a length less than the lower link (1). One end of the link is linked in a form of pivot or rotational axis (5) to a chassis (4) and other end linked in a form of pivot or rotational axis (5) to one end of a compensation link (3).

[0020] A compensation link (3) aligned vertically or nearly, having one end linked in a form of pivot or rotational axis (5) to one end of the upper link (2), the body linked in a form of pivot or rotational axis (5) with one end of the lower link (1), and the other end linked in the form of pivot or rotational axis (5) with any parts of solid axle or beam axle (6) or any parts assembled as solid axle or beam axle (6), such as differential cover or any parts requiring control of relative movement to a chassis (4).

[0021] A chassis (4) has a stable and strong structure or frame, having assemblies mounted by welding, bolts or linked with another parts by pivot or rotational axis (5).

[0022] The lower link (1), the upper link (2) and the compensation link (3) are characterized as one single solid body or parts assembled as one single solid body, such as upper link (2), as shown in FIG. 3A, 3B and 3C, the links linked together in a form of pivot or rotational axis (5) at the body and both ends, such as the compensation link (3), or linked only at both ends, such as the lower link (1) and the upper link (2). All the lower link (1), the upper link (2) and the compensation link (3) have at least 1 linkage at the body or at both ends such as the lower link (1) as shown in FIG. 3C.

[0023] A solid axle (6) is characterized as a rigid structure with low torsibility. Within the structure, differential, powertrain system or motor (7) may be additionally provided. A beam axle (6) is characterized as being able to twist longitudinally. Both solid axle and beam axle (6) comprise wheels (8) at both ends as shown in FIG. 2.

[0024] According to FIG.1A, IB, 1C and FIG. 2, a sideways movement (S-S) of the solid axle (6) or beam axle (6) with wheels (8) installed at both ends occurs from a fixed length of the lower link (1). The 3-link mechanism compensates the fixed length with compensation link (3) pushed and pulled by the upper link (2) in relation to the vertical movement of solid axle (6) or beam axle (6). The quantity of compensation of the 3-link mechanism is enabled by adjusting the proportion of lengths and linkage positions of the 3 links, or the linked position to the chassis (4) in the form of pivot or rotational axis (5) of the lower link (1) and the upper link (2). The most suitable compensation is that this proportion adjustment of lengths AB embodiment and BC embodiment of the compensation link (3) and the 3-link mechanism is most efficient when the length of the upper link (2) is less than the lower link (1) and all 3 links linked in the form of perpendicular as shown in FIG. IB.

[0025] Brief Description of the Drawings

[0026] FIG. 1A illustrates a 3-link mechanism in the event that a compensation link (3) aligns vertically or nearly in a low position, compensating the sideways movement (S-S).

[0027] FIG. IB illustrates the 3-link mechanism in the event that a compensation link (3) aligns vertically at a range of angles of perpendicular position with a lower link (1) and upper link (2) without providing any compensation for sideways movement (S-S).

[0028] FIG. 1C illustrates the 3-link mechanism in the event that a compensation link (3) aligns vertically or nearly in a high position, compensating the sideways movement (S-S).

[0029] FIG. 2 illustrates the 3-link mechanism in the event that a compensation link (3) aligns vertically or nearly in a low position, compensating the sideways movement (S-S). One end linked to a solid axle or beam axle (6) with wheel (8) installed at both ends. In addition, this 3-link mechanism has a roll center (RC) in a position lower than Panhard rod.

[0030] FIG. 3A, 3B, 3C illustrate the lower link (1), the upper link (2) and the compensation link (3) with different shape and form linked as 3-link mechanism, but the explanation of all 3 links are the same.

[0031] Best Mode of the Invention

[0032] As described in the Detailed Description of the Invention.

[0033] Industrial Applicability

[0034] The 3-link mechanism invention is applied to motor vehicle industry as regards suspensions or to other inventions seeking to control relative movement between 2 parts which are chassis (4) and solid axle or beam axle (6), according to this invention.

Claims

AMENDED CLAIMS received by the International Bureau on 02 January 2025 (02.01.2025)1. The 3-link mechanism comprising 1. lower link (1) 2. upper link (2) and 3. compensation link (3), having one side rotationally connected (5) to the central portion of the axle beam (6), wherein an axle beam (6) holds left and right wheels (8) and supports the rotation of the left and right wheels (8) at both ends, and the other side rotationally connected (5) to the mounting portion of the vehicle body side member (4) with the following specific conditions: a lower link (1), functioning as a link arm, horizontally aligned or near horizontally, being longer and located at the bottom of the upper link (2), having one end rotationally connected (5) to mounting portion of the vehicle body side member (4) and the other end rotationally connected (5) to the central portion of the compensation link (3), an upper link (2), functioning as a link arm, horizontally aligned or near horizontally, having one end rotationally connected (5) to mounting portion of the vehicle body side member (4) and the other end rotationally connected (5) to one end of the compensation link (3), and a compensation link (3), functioning as a link arm, vertically aligned or near vertically, having one end rotationally connected (5) to one end of the upper link (2), the central portion rotationally connected (5) to one end of the lower link (1), and the other end rotationally connected (5) to a central portion of the axle beam (6); for vehicles with a normal body height condition where there is no load and body does not roll, the lower link (1), upper link (2), and axle beam (6) are positioned horizontally or near horizontally, parallel or near parallel, and perpendicular or near perpendicular to the compensation link (3).

2. The 3-link mechanism according to claim 1, wherein vehicle with normal body height condition where there is no load and body does not roll, the lower link (1) and upper link (2) have one end rotationally connected (5) to the mounting portion of the vehicle body side member (4), and the same side member (4) connected to the left or right of the compensation link (3) when viewed from above and rearward.

3. The 3-link mechanism according to claims 1 or 2, wherein the lower link (1), upper link (2), and compensation link (3) have a single or double rotationally connected (5) at both ends to preventthe 3 -link mechanism from swinging rearward and forward due to acceleration and deceleration, respectively.

4. The 3-link mechanism according to claims 1, 2, or 3, wherein the lower link (1) and upper link (2) do not always align overlap when viewed from above, by creating an angle at rotationally connected (5) to the compensation link (3), resulting in two other ends rotationally connected (5) to the mounting portion of the vehicle body side member (4) separating to prevent the 3-link mechanism from swinging rearward and forward due to acceleration and deceleration, respectively.[0001][0002]STATEMENT UNDER ARTICLE 19 (1)[0003]The 3-link mechanism consists of three link arms similar to DI, having one side rotationally connected to the mounting portion of the vehicle body side member and the other side rotationally connected to a central portion of the axle beam. However, both three-link arms have different arrangements according to the specific conditions of the new claims and also have different horizontal and vertical movements when the axle beam moves up and down from the bump and rebound, respectively. Additionally, the 3-link mechanism has an inventive step as follows:[0004]1. Reduction of buckling at the central portion of the compensation link due to the length of the compensation link and lateral force is reduced by keeping the compensation link vertical or near vertical, resulting in a shorter compensation link and the 3-link mechanism being the most compact as in new claims 1 and 2.[0005]2.Reduction of sway of the 3-link mechanism rearward and forward due to acceleration and deceleration, respectively, by the compact mechanism and method of new claims 3 and 4, not mentioned by Dl's claims.

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