Suspension structure

Abstract

This disclosure provides a suspension structure that can improve steering feel. [Solution] The suspension structure according to this disclosure is a suspension structure 10 in which a steering gearbox 12 is fastened to a boss 13 provided on a suspension member 11 and having a screw hole for fastening the steering gearbox 12, wherein the diameter of the boss 13 is larger on the side fastening the steering gearbox than on the front side of the vehicle body.

Description

Technical Field

[0001] The present disclosure relates to a suspension structure.

Background Art

[0002] Patent Document 1 discloses an automotive suspension device that improves steering responsiveness by adjusting the hardness of a bush in a multi-link type suspension structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in order to reduce the weight of an automobile, it has been proposed to change the material of the suspension structure from iron to aluminum. FIG. 4 illustrates the toe rigidity in the case of an iron suspension structure 35 and an aluminum suspension structure 30. In FIG. 4, the horizontal axis represents the lateral force applied to the wheel, and the vertical axis represents the toe-in angle. In FIG. 4, the numerical values of the horizontal axis and the vertical axis are omitted, but the value is larger on the right side of the horizontal axis and larger on the upper side of the vertical axis. As shown in FIG. 4, in the aluminum suspension structure 30 (the suspension structure according to the comparative example described later), the toe-in angle is smaller for the same lateral force compared to the iron suspension structure 35. Therefore, it can be seen that the aluminum suspension structure 30 (the suspension structure according to the comparative example described later) has higher toe rigidity than the iron suspension structure 35.

[0005] Figure 5 also illustrates the yaw rate with respect to steering angle for both iron and aluminum suspension structures. In Figure 5, the values ​​on the vertical axis are omitted, but the higher the value on the vertical axis, the larger the value. Focusing on the area around a steering angle of 0 degrees shown in Figure 5, the iron suspension structure shows variable data, indicating an unstable yaw rate. In contrast, the aluminum suspension structure (the suspension structure related to the comparative example described later) shows less variability, indicating a stable yaw rate.

[0006] In other words, as shown in Figures 4 and 5, the aluminum suspension structure has higher toe rigidity and more stable yaw rate compared to the steel suspension structure. However, subjective evaluations of the aluminum suspension structure sometimes showed that the steering feel was not appropriate.

[0007] This disclosure has been made in view of these circumstances and provides a suspension structure that can improve steering feel. [Means for solving the problem]

[0008] The suspension structure relating to this disclosure is A suspension structure in which a steering gearbox is fastened to a hollow boss provided on a suspension member, The outer diameter of the boss is larger on the side that fastens the steering gearbox than on the side facing the front of the vehicle.

[0009] In the suspension structure disclosed herein, the outer diameter of the boss is larger on the side that fastens the steering gearbox than on the front side of the vehicle. By having this configuration, the steering gearbox deforms more in the suspension structure disclosed herein, and the steering reaction force increases. Therefore, the suspension structure disclosed herein provides an appropriate steering reaction force, reduces the gap between the steering reaction force and the turning motion of the vehicle, and improves the steering feel.

[0010] The suspension structure according to this disclosure may have an opening provided near the boss of the suspension member. Even with such a configuration, a suitable steering reaction force is obtained, reducing the gap between the steering reaction force and the turning motion of the vehicle, and improving the steering feel.

[0011] The outer diameter of the boss may be configured to decrease from the side that fastens the steering gearbox toward the front of the vehicle. Even with such a configuration, a suitable steering reaction force is obtained, reducing the gap between the steering reaction force and the vehicle's turning motion, and improving the steering feel. [Effects of the Invention]

[0012] This disclosure provides a suspension structure that can improve steering feel. [Brief explanation of the drawing]

[0013] [Figure 1] This is an xz plan view of the suspension structure according to Embodiment 1. [Figure 2] This is a cross-sectional view of the suspension structure according to Embodiment 1, using the yz direction. [Figure 3] This figure shows the results of analyzing the deformation amounts of the suspension structure according to the comparative example and the suspension structure according to Embodiment 1. [Figure 4] This diagram shows the toe stiffness for steel suspension structures and aluminum suspension structures. [Figure 5] This figure shows the yaw rate with respect to the steering angle for iron suspension structures and aluminum suspension structures. [Modes for carrying out the invention]

[0014] Hereinafter, the present disclosure will be described through embodiments of the invention. However, the invention according to the claims is not limited to the following embodiments. Also, not all of the configurations described in the embodiments are essential as means for solving the problems. For the sake of clarity of explanation, the following description and drawings have been appropriately omitted and simplified. In each drawing, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted as necessary.

[0015] Of course, the right-handed xyz orthogonal coordinates shown in the drawings are for convenience in explaining the positional relationship of the components. Usually, the positive direction of the z-axis is vertically upward, and the xy plane is the horizontal plane.

[0016] (Embodiment 1) <Suspension Structure> First, referring to FIGS. 1 and 2, the configuration of the suspension structure according to Embodiment 1 will be described. FIG. 1 is an xz plane view of the suspension structure according to Embodiment 1. FIG. 2 is a yz cross-sectional view of the suspension structure according to Embodiment 1. In FIGS. 1 and 2, the positive x-axis side is the left side of the vehicle body (left side as viewed from the vehicle body), the negative y-axis side is the front of the vehicle body, and the positive z-axis side is the upper side of the vehicle body.

[0017] As shown in FIG. 1, the suspension structure 10 includes a suspension member 11 and a steering gear box 12. As shown in FIG. 1, a steering column 15 and two tie rods 16 are fastened to the steering gear box 12.

[0018] A steering wheel is fastened to the tip side of the steering column 15 shown in FIG. 1. A left wheel is fastened to the tie rod 16 provided on the positive x-axis side (see FIG. 1). The left side means the left side as viewed from the vehicle body. A right wheel is fastened to the tie rod 16 provided on the negative x-axis side (see FIG. 1). The right side means the right side as viewed from the vehicle body.

[0019] As shown in FIG. 1, the suspension member 11 extends in the vehicle width direction (x-axis direction) between the left and right front wheels and is also referred to as a subframe. As shown in FIG. 1, the steering gear box 12 is provided on the back side of the suspension member 11, that is, on the positive y-axis side and on the inner side of the vehicle body with respect to the suspension member 11. The suspension member 11 protects the steering gear box 12 from being impacted from outside the vehicle body. The suspension member 11 is made of, for example, aluminum.

[0020] Referring to FIG. 2, the suspension member 11 and the steering gear box 12 will be described with attention paid thereto. As shown in FIG. 2, the suspension member 11 includes a boss 13. The steering gear box 12 and the suspension member 11 are fastened by a bolt 25 via the boss 13 and a bush 17. The bush 17 has a hollow shape and is made of, for example, a rubber material.

[0021] <boss> As shown in FIGS. 1 and 2, the boss 13 is provided on the suspension member 11 and has a hollow shape. As shown in FIG. 2, the inner peripheral surface 13a of the boss 13 is threaded to correspond to the bolt 25 so that the steering gear box 12 can be fastened. The boss 13 has a threaded hole with a distance e1. For example, when the bolt 25 is a single-thread bolt, the inner peripheral surface 13a of the boss 13 is threaded to correspond to the length of the bolt 25.

[0022] Note that FIG. 2 shows an example in which the bolt 25 is inserted up to a part of the inner peripheral surface 13a of the boss 13, but it is not limited thereto, and the bolt 25 may be inserted into all of the inner peripheral surface 13a of the boss 13. In other words, the length of the bolt 25 may be any length as long as the steering gear box 12 and the suspension member 11 are fastened by the bolt 25.

[0023] Referring to Figure 2, the outer diameter of the boss 13 will be explained. As shown in Figure 2, the boss 13 has a diameter of distance d1 on the side that fastens to the steering gearbox 12 (positive y-axis side). Also, as shown in Figure 2, the boss 13 has a diameter of distance d2 on the front side of the vehicle body (negative y-axis side). As shown in Figure 2, distance d1 is greater than distance d2.

[0024] In other words, as shown in Figure 2, the outer diameter of the boss 13 is larger on the side that fastens the steering gearbox 12 than on the front side of the vehicle. Furthermore, the outer diameter of the boss 13 is not limited to the example shown in Figure 2, and may be made smaller from the side that fastens the steering gearbox towards the front of the vehicle.

[0025] <Opening> Furthermore, as shown in Figures 1 and 2, the suspension member 11 is provided with an opening G1 near the boss 13. In the example shown in Figure 2, the opening G1 is located directly above the boss 13 (on the positive z-axis side).

[0026] In the example shown in Figure 2, the opening G1 has an opening area approximately the same as the inner circumference of the boss 13. However, it is not limited to this, and the opening G1 can be configured to have a predetermined opening area according to the size of the suspension member 11. Also, although there is only one opening G1 in the example shown in Figure 2, a configuration with multiple openings G1 is also possible.

[0027] Thus, in the suspension structure 10 according to Embodiment 1, the outer diameter of the boss 13 is larger on the side that fastens the steering gearbox 12 than on the front side of the vehicle body, and an opening G1 is provided near the boss 13.

[0028] <Amount of deformation> The amount of deformation of the suspension structure according to Embodiment 1 will be explained with reference to Figure 3. Figure 3 is a diagram showing the results of analyzing the amount of deformation of the suspension structure 30 according to the comparative example and the suspension structure 10 according to Embodiment 1.

[0029] The comparative example suspension structure 30 is a structure in which the outer diameter of the boss 13 shown in Figure 2 is constant from the side fastening the steering gearbox 12 to the front of the vehicle body, and there is no opening G1 near the boss 13. In Figure 3, for the sake of clarity, the suspension member 11 and the steering gearbox 12 are shown. The comparative example suspension structure 30 is an aluminum suspension structure as shown in Figures 4 and 5.

[0030] In Figure 3, the upper panel shows the analysis results of the deformation amount of the suspension structure 30 according to the comparative example, and the lower panel shows the analysis results of the deformation amount of the suspension structure 10 according to Embodiment 1. In Figure 3, black indicates a larger deformation amount, and white indicates a smaller deformation amount. Here, we will focus on the ranges A1 and A2 shown in Figure 3.

[0031] As shown in Figure 3, in range A2, there is no difference in the amount of deformation between the suspension structure 30 according to the comparative example and the suspension structure 10 according to embodiment 1.

[0032] As shown in Figure 3, in range A1, the suspension structure 10 according to Embodiment 1 has a greater region of large deformation of the steering gearbox 12 compared to the suspension structure 30 according to the comparative example. This is thought to be due to the following:

[0033] The steering gearbox 12 is composed of springs and can therefore be considered an elastic member. In the suspension structure 10 according to Embodiment 1, the outer diameter of the boss 13 is larger on the side that fastens the steering gearbox 12 than on the front side of the vehicle body, compared to the suspension structure 30 according to the comparative example, and an opening G1 is provided. As a result, in the suspension structure 10 according to Embodiment 1, the rigidity of the suspension member near the steering gearbox mounting portion (boss 13) is lower compared to the suspension structure 30 according to the comparative example. As a result, in the suspension structure 10 according to Embodiment 1, the steering gearbox 12 is thought to deform more elastically than in the suspension structure 30 according to the comparative example, and the amount of deformation of the steering gearbox 12 (range A1) is considered to be larger.

[0034] In other words, in the suspension structure 10 according to Embodiment 1, the outer diameter of the boss 13 is larger on the side that fastens the steering gearbox 12 than on the front side of the vehicle body, and an opening G1 is provided. As a result, in the suspension structure 10 according to Embodiment 1, as shown in Figure 3, the steering gearbox 12 (range A1) can be deformed more, without changing the range (range A2) that affects the mounting of the body and the mounting of the arms.

[0035] <Steering feel> Furthermore, as shown in Figures 4 and 5, the suspension structure 30 in the comparative example, despite having high toe rigidity and a stable yaw rate, lacked steering feel in subjective evaluations. Specifically, the steering reaction force felt by the driver was weak, resulting in a gap between the steering reaction force and the vehicle's turning motion.

[0036] On the other hand, the suspension structure 10 according to Embodiment 1 yielded similar results to those in Figures 4 and 5, exhibiting high toe rigidity, stable yaw rate, and improved steering feel in subjective evaluations. In other words, there was no gap between the steering reaction force and the vehicle's turning motion, allowing the driver to obtain an appropriate steering feel. This is thought to be due to the following reasons.

[0037] As shown in Figure 3, in the suspension structure 10 according to Embodiment 1, the outer diameter of the boss 13 is larger on the side that fastens the steering gearbox 12 than on the front side of the vehicle body, and an opening G1 is provided. As a result, the steering gearbox 12 (range A1) is deformed more. This increases the self-alignment torque and the steering reaction force. Therefore, in the suspension structure 10 according to Embodiment 1, an appropriate steering reaction force is obtained, the gap between the steering reaction force and the turning motion of the vehicle is reduced, and the steering feel is improved.

[0038] Thus, in the suspension structure 10 according to Embodiment 1, the outer diameter of the boss 13 is larger on the side that fastens the steering gearbox 12 than on the front side of the vehicle body, and an opening G1 is provided. By having this configuration, the suspension structure 10 according to Embodiment 1 can improve steering feel.

[0039] In conventional technology, steering feel is improved by setting the hardness of the bushings. However, since bushings are made of rubber, there is a risk that the appropriate steering feel may not be obtained as they deteriorate over time. In contrast, the suspension structure 10 according to Embodiment 1 improves steering feel by allowing the steering gearbox 12 to deform more, so that the appropriate steering feel can be obtained without deterioration over time, enabling driving that is exactly as intended.

[0040] In the above description, the suspension structure 10 according to Embodiment 1 was explained as having a boss 13 whose diameter is larger on the side that fastens to the steering gearbox 12 than on the front side of the vehicle body, and an opening G1 is provided.

[0041] However, the suspension structure 10 according to Embodiment 1 may also have a structure in which the diameter of the outer circumference of the boss 13 on the side fastening the steering gearbox 12 is larger than that on the front side of the vehicle body, or a structure in which the opening G1 is provided. In this case as well, the steering feel can be improved for the same reasons as described above.

[0042] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from its intent. [Explanation of Symbols]

[0043] 10. Suspension Structure 11 Suspension Member 12 Steering gearbox 13 Bosses 13a Inner surface 15 Steering column 16 Tie Rods 17 Bush 25 volts A1 Range A2 Range d1, d2, e1 distance G1 aperture

Claims

1. A suspension structure in which a steering gearbox is fastened to a hollow boss provided on a suspension member, The outer diameter of the boss is larger on the side that fastens the steering gearbox than on the front side of the vehicle body. Suspension structure.

2. An opening is provided near the boss of the suspension member. The suspension structure according to claim 1.

3. The outer diameter of the boss decreases from the side that fastens the steering gearbox toward the front of the vehicle body. The suspension structure according to claim 1 or 2.

Images