Vehicle undercarriage

Abstract

In vehicles equipped with a De Dion suspension system, damage to the driveshaft caused by off-road driving is suppressed. [Solution] A De Dion suspension system 30 comprising a drive unit 20, axle hubs 31L, 31R, axle beam 32, left and right coil springs 41L, 41R, and drive shafts 34L, 34R, and a vehicle understructure 100 comprising left and right lateral rods 42L, 42R, and mounts 11, 12 for attaching the drive unit 20 to the body 10, the lateral rods 42L, 42R being rotatably connected to the axle hubs 31L, 31R and the drive unit 20, and the mounts 11, 12 supporting the drive unit 20 so that the drive unit 20 can oscillate around the longitudinal axis 20C of the drive unit 20.

Description

Technical Field

[0001] The present disclosure relates to a vehicle underbody structure including a De Dion type suspension device.

Background Art

[0002] Patent Document 1 discloses a vehicle equipped with a De Dion type suspension device and having a motor mounted on the body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the vehicle travels off - road, the wheels move vertically with respect to the body, and a vertical displacement occurs between the output shaft of the motor and the rotation axis of the wheels. This vertical displacement is absorbed by the bending of the drive shaft of the De Dion type suspension device. However, when the wheels move significantly vertically with respect to the body during off - road driving, the bending angle of the drive shaft becomes large, and there is a possibility that the joint of the drive shaft is damaged.

[0005] An object of the present disclosure is to suppress damage to the drive shaft due to off - road driving in a vehicle including a De Dion type suspension device.

Means for Solving the Problems

[0006] The vehicle understructure of the present disclosure is characterized in that it comprises a drive unit attached to the body, a De Dion suspension system comprising left and right axle hubs supporting left and right wheels, an axle beam connecting the left and right axle hubs in the vehicle width direction, left and right springs disposed between the body and the left and right ends of the axle beam, and left and right drive shafts transmitting driving force from the drive unit to the left and right wheels, left and right lateral rods connecting the left and right axle hubs and the drive unit, and two mounts for attaching the drive unit to the body, wherein both ends of the lateral rods are rotatably connected to the axle hubs and the drive unit, and the two mounts are attached to the front and rear of the drive unit to support the drive unit so that the drive unit can oscillate around a longitudinal axis.

[0007] As a result, when the wheels move vertically relative to the body, the drive unit oscillates around the longitudinal axis in accordance with the direction of wheel movement, making the bending angle of the drive shaft smaller than that of the conventional vehicle described in Patent Document 1. This helps to suppress damage to the drive shaft caused by off-road driving. [Effects of the Invention]

[0008] This disclosure makes it possible to suppress damage to the drive shaft caused by off-road driving in vehicles that include a De Dion suspension system. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view of the undercarriage structure of the vehicle according to the embodiment. [Figure 2] This is an elevation view of the undercarriage of the vehicle according to the embodiment, as seen from the rear of the vehicle. [Figure 3] This is an elevation view showing the operation of various parts of a vehicle equipped with the vehicle understructure of the embodiment while it is driving off-road. [Modes for carrying out the invention]

[0010] The vehicle understructure 100 of the embodiment will be described below with reference to the drawings. FR, UP, and RH in each figure indicate the front, upper, and right sides, respectively, of the vehicle 200 equipped with the vehicle understructure 100. The opposite directions of FR, UP, and RH indicate the rear, lower, and left sides. Hereafter, when simply using the front / rear, left / right, and up / down directions, unless otherwise specified, these refer to the front / rear, left / right, and up / down directions of the vehicle 200. Furthermore, the front / rear, left / right, and up / down directions of the vehicle understructure 100 refer to the front / rear, left / right, and up / down directions of the vehicle 200.

[0011] As shown in Figures 1 and 2, the vehicle understructure 100 includes a drive unit 20, a De Dion suspension system 30, left and right lateral rods 42L and 42R, and a front mount 11 and a rear mount 12.

[0012] The drive unit 20 may be, for example, an electric drive unit including a drive motor, gears, and an inverter. The drive unit 20 is equipped with left and right output shafts 23L and 23R that output driving force. The left and right output shafts 23L and 23R protrude from the left and right surfaces of the drive unit 20 in the left and right directions. The drive unit 20 is also provided with left and right rod mounting seats 24L and 24R to which the left and right lateral rods 42L and 42R, which will be described later, are connected.

[0013] The front of the drive unit 20 is provided with a front bracket 21 that protrudes forward. The rear of the drive unit 20 is provided with a rear bracket 22 that protrudes backward. The front bracket 21 and the rear bracket 22 are positioned on the axis of the longitudinal axis 20C of the drive unit 20. The front bracket 21 and the rear bracket 22 are supported by a front mount 11 and a rear mount 12 attached to the body 10. The front bracket 21 and the rear bracket 22 may be circular, for example, and the front mount 11 and the rear mount 12 may be cylindrical and pivotably support the front bracket 21 and the rear bracket 22 on their inner cylindrical surfaces. In this way, the drive unit 20 is mounted to the body 10 so as to be pivotable around the longitudinal axis 20C.

[0014] The De Dion suspension system 30 includes left and right axle hubs 31L and 31R, an axle beam 32, left and right coil springs 41L and 41R, and left and right drive shafts 34L and 34R. The De Dion suspension system 30 suspends the left and right wheels 18L and 18R.

[0015] The right axle hub 31R of the De Dion suspension system 30 rotatably supports the right wheel 18R. Here, the right wheel 18R includes a wheel hub 14R, a rotating shaft 15R, a wheel 16R, and a tire 17R. The rotating shaft 15R of the wheel 18R is mounted on the inner side of the wheel hub 14R in the vehicle width direction. The wheel 16R is fastened to the outer side of the wheel hub 14R in the vehicle width direction. The tire 17R is fitted around the outer circumference of the wheel 16R.

[0016] The outer portion of the right axle hub 31R in the vehicle width direction has a hole through which the rotating shaft 15R of the right wheel 18R passes. A bearing (not shown) that supports the rotating shaft 15R is provided inside the hole. The inner portion of the right axle hub 31R in the vehicle width direction is hollow. The right outer shaft 39R and the right outer joint 38R of the right drive shaft 34L, which will be described later, are housed inside the hollow portion. The right axle hub 31R is also provided with a hub-side rod mounting seat 33R to which the right lateral rod 42R, which will be described later, is connected.

[0017] The left wheel 18L, like the right wheel 18R, includes a wheel hub 14L, a rotating shaft 15L, a wheel 16L, and a tire 17L. The configuration of the left wheel 18L is symmetrical to that of the right wheel 18R. The left axle hub 31L rotatably supports the left wheel 18L. The configuration of the left axle hub 31L is symmetrical to that of the right axle hub 31R. The left axle hub 31L is provided with a hub-side rod mounting seat 33L to which the left lateral rod 42L is connected.

[0018] The axle beam 32 is a skeletal member that connects between the left and right axle hubs 31L and 31R in the vehicle width direction. As shown in FIG. 1, the axle beam 32 is curved in an arcuate shape such that the central portion in the vehicle width direction protrudes rearward of the vehicle.

[0019] As shown in FIGS. 1 and 2, left and right coil springs 41L and 41R are arranged between the body 10 of the vehicle 200 and the left and right end portions of the axle beam 32. The body 10 is supported by the left and right coil springs 41L and 41R, the axle beam 32, the left and right axle hubs 31L and 31R, and the left and right wheels 18L and 18R.

[0020] The right drive shaft 34R includes an inner shaft 35R, an inner joint 36R, a connection shaft 37R, an outer joint 38R, and an outer shaft 39R. The inner joint 36R is a universal joint capable of connecting the inner shaft 35R and the connection shaft 37R at an angle. The outer joint 38R is a universal joint capable of connecting the outer shaft 39R and the connection shaft 37R at an angle. The angle between the inner shaft 35R and the connection shaft 37R is the joint angle of the inner joint 36R. Also, the angle between the outer shaft 39R and the connection shaft 37R is the joint angle of the outer joint 38R.

[0021] The inner shaft 35R is connected to the right output shaft 23R of the drive unit 20 so as to be coaxial. The outer shaft 39R is connected to the rotation shaft 15R of the right wheel 18R so as to be coaxial. Accordingly, the angle between the output shaft 23R and the connection shaft 37R is also the joint angle of the inner joint 36R. Also, the angle between the rotation shaft 15R and the connection shaft 37R is also the joint angle of the outer joint 38R.

[0022] Similarly, the left drive shaft 34L includes an inner shaft 35L, an inner joint 36L, a connecting shaft 37L, an outer joint 38L, and an outer shaft 39L. The structure of the left drive shaft 34L is bilaterally symmetric with the structure of the right drive shaft 34R. The inner shaft 35L is connected to the left output shaft 23L of the drive unit 20 so as to be coaxial. The outer shaft 39L is connected to the rotating shaft 15L of the left wheel 18L so as to be coaxial.

[0023] The left and right lateral rods 42L and 42R connect the drive unit 20 and the left and right axle hubs 31L and 31R.

[0024] The right lateral rod 42R is composed of an inner rod 42A, an outer rod 42B, and a damper 42C. The inner rod 42A and the outer rod 42B are linearly connected via the damper 42C. The inner end of the inner rod 42A is connected to the rod mounting seat 24R of the drive unit 20 via an elastic member. The elastic member connects the inner rod 42A and the rod mounting seat 24R so that the inner end of the inner rod 42A can rotate around the vehicle longitudinal axis. Also, the outer end of the outer rod 42B is rotatably connected to the hub-side rod mounting seat 33R of the right axle hub 31R around the vehicle longitudinal axis. Thus, the right lateral rod 42R is rotatably connected to the drive unit 20 and the right axle hub 31R.

[0025] The left lateral rod 42L is bilaterally symmetric with the right lateral rod 42R. Similar to the right lateral rod 42R, the left lateral rod 42L is rotatably connected to the drive unit 20 and the left axle hub 31L.

[0026] Next, referring to FIG. 3, the movement of each part when the vehicle 200 equipped with the vehicle lower structure 100 is traveling off-road will be described.

[0027] Figure 3 shows the state in which the vehicle 200 is driving off-road, and the right wheel 18R has driven onto a protrusion 55 on the ground 50, causing the wheel 18R to move upward. As indicated by arrow 91 in Figure 3, when the right wheel 18R moves upward, the right axle hub 31R also moves upward. As a result, the left and right lateral rods 42L and 42R pull the drive unit 20 to the left and right, as shown by arrows 92L and 92R in Figure 3, to maintain the distance between the drive unit 20 and the left and right axle hubs 31L and 31R. Then, as shown by arrow 93 in Figure 3, the drive unit 20 oscillates counterclockwise by an angle β relative to the body 10 until the pulling forces of the left and right lateral rods 42L and 42R are balanced. As a result, the output shaft 23R of the drive unit 20 is tilted by an angle β relative to the body 10.

[0028] Furthermore, when the right wheel 18R moves upward, the right connecting shaft 37R is tilted counterclockwise by an angle α relative to the right output shaft 23R of the drive unit 20. In other words, the joint angle of the inner joint 36R is angle α. Consequently, the right connecting shaft 37R is tilted by an angle α+β relative to the body 10.

[0029] On the other hand, if the drive unit 20 does not oscillate relative to the body 10, as in the vehicle described in Patent Document 1, the output shaft 23R of the drive unit 20 does not tilt relative to the body 10, so the right connecting shaft 37R is tilted by an angle α+β relative to the right output shaft 23R of the drive unit 20. In this case, the joint angle of the inner joint 36R is α+β.

[0030] Therefore, in the vehicle understructure 100 of this embodiment, the joint angle of the inner joint 36R when the wheel 18R moves upward can be reduced by an angle β, which is the oscillation angle of the drive unit 20.

[0031] Thus, the vehicle understructure 100 of this embodiment can reduce the bending angle of the drive shaft 34R when the wheel 18R moves upward compared to when the drive unit 20 does not oscillate. This reduces the joint angle of the inner joint 36R and suppresses damage to the inner joint 36R. Similarly, the vehicle understructure 100 of this embodiment can reduce the joint angle of the outer joint 38R and reduce damage to the outer joint 38R.

[0032] As explained above, when the wheels 18L and 18R move vertically relative to the body 10, the drive unit 20 of the vehicle understructure 100 oscillates around the longitudinal axis 20C in accordance with the direction of movement of the wheels 18L and 18R. This allows the bending angle of the drive shafts 34L and 34R to be smaller than that of the drive shafts of the conventional vehicle described in Patent Document 1. As a result, the vehicle understructure 100 can suppress damage to the drive shafts 34L and 34R caused by off-road driving.

[0033] Furthermore, if the drive unit 20 is an electric unit, the drive unit 20 is supported at two points, the front and rear, which are far from the motor mounted inside. Therefore, the drive unit 20 can be supported by front brackets 21 and rear brackets 22 with low rigidity, or front mounts 11 and rear mounts 12 with low rigidity. [Explanation of Symbols]

[0034] 10 Body, 11 Front mount, 12 Rear mount, 14L, 14R Wheel hub, 15L, 15R Rotating shaft, 16L, 16R Wheel, 17L, 17R Tire, 18L, 18R Wheel, 20 Drive unit, 20C Front / rear axle, 21 Front bracket, 22 Rear bracket, 23L, 23R Output shaft, 24L, 24R Rod mounting seat, 30 De Dion suspension, 31L, 31R Axle hub, 32 Axle beam, 33L, 33R Hub-side rod mounting seat, 34L, 34R Drive shaft, 35L, 35R Inner shaft, 36L, 36R Inner joint, 37L, 37R Connecting shaft, 38L, 38R Outer joint, 39L, 39R Outer shaft, 41L, 41R Coil spring, 42A Inner rod, 42B; Outer rod, 42C; Damper, 42L, 42R; Lateral rod, 50; Ground, 55; Protrusion, 100; Vehicle understructure, 200; Vehicle.

Claims

[Claim 1] The drive unit attached to the body, De Dion suspension system, The left and right axle hubs that support the left and right wheels, an axle beam connecting the left and right axle hubs in the vehicle width direction, The left and right springs are positioned between the body and the left and right ends of the axle beam, A De Dion suspension system comprising left and right drive shafts that transmit driving force from the drive unit to the left and right wheels, The left and right axle hubs and the left and right lateral rods connecting the drive unit, A vehicle understructure comprising two mounts for attaching the drive unit to the body, The lateral rod is rotatably connected at both ends to the axle hub and the drive unit, The two mounts are attached to the front and rear of the drive unit to support the drive unit so that it can oscillate around the longitudinal axis. A vehicle understructure characterized by the following.

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