JP7633079B2 - Suspension device and vehicle body structure - Google Patents

Description

This disclosure relates to a suspension device and a vehicle body structure.

Leaf springs are used as suspension devices for automobiles. For example, Patent Document 1 describes a suspension device that includes a leaf spring that suspends the front wheels via a front axle tube and a shock absorber that dampens vibrations of the leaf spring. In this device, the front end of the leaf spring is connected to a frame extending in the fore-and-aft direction via a bracket, and the rear end of the leaf spring is connected to the frame via a shackle and a bracket.

Japanese Patent Application Publication No. 7-257129

In recent years, there has been progress in the development of electric vehicles that run by driving a motor with battery power. In electric vehicles, electrical components such as a battery, motor, and inverter are mounted on the body frame of the vehicle. The performance requirements for electric vehicles are increasing year by year, and the capacity of the batteries mounted on the vehicles is also increasing accordingly. In order to mount a large-capacity battery, for example, it is conceivable to configure the body frame of the vehicle to include a pair of side rails extending in the front-rear direction of the vehicle, a cross member extending in the width direction of the vehicle and connecting the pair of side rails, and a pair of rear rails connected to a midpoint in the extension direction of the cross member and extending from the cross member to the rear of the vehicle, and to form a space for mounting the battery between the pair of side rails and the cross member.

In such a configuration, the load is concentrated at the connection between the cross member and the pair of rear rails. In particular, when leaf springs are connected to the pair of rear rails as in Patent Document 1, the load of the leaf springs is applied to the pair of rear rails, so the connection between the cross member and the pair of rear rails requires significant reinforcement. Such reinforcement leads to an increase in the number of parts, which causes the vehicle to become heavier.

Therefore, this disclosure aims to prevent the vehicle from becoming too heavy.

In one aspect, a suspension device is provided that is attached to a vehicle body frame including a pair of side rails extending in the longitudinal direction of the vehicle, a cross member extending in the width direction of the vehicle and connecting the pair of side rails, and a pair of rear rails connected to a midpoint in the extension direction of the cross member and extending from the cross member to the rear of the vehicle. This suspension device includes a leaf spring that is disposed on the outer side of the pair of rear rails in the width direction of the vehicle and supports the rear axle of the vehicle, and a front spring bracket that connects a front end of the leaf spring to the cross member.

In the suspension device according to this embodiment, the front end of the leaf spring is connected to the cross member via the front spring bracket. Therefore, the load from the leaf spring is transmitted to the cross member, and the concentration of the load on the pair of rear rails is suppressed. As a result, the load transmitted to the connection between the cross member and the pair of rear rails is reduced, and it is possible to simplify the reinforcement of the connection. This makes it possible to suppress an increase in the weight of the vehicle.

In one embodiment, the vehicle may further include a rear spring bracket that connects the rear end of the leaf spring to the pair of rear rails. In this configuration, the load of the leaf spring can be distributed to the cross member and the pair of rear rails.

In one embodiment, the front spring bracket may be connected to the cross member so that the front end of the leaf spring can rotate about an axis parallel to the extension direction of the cross member. By connecting the front end of the leaf spring to the cross member so that it can rotate about an axis parallel to the extension direction of the cross member, it becomes possible to position the axis of the front spring bracket close to the body frame, and therefore the moment acting on the front spring bracket is reduced. Therefore, the strength required of the front spring bracket is reduced, and the structure of the front spring bracket can be simplified. As a result, the weight of the vehicle can be further suppressed.

In one embodiment, the cross member has a hollow structure with a rectangular cross section including an upper surface facing the upper side of the vehicle, a lower surface facing the lower side of the vehicle, and a pair of side surfaces facing in the fore-aft direction of the vehicle, and the front spring bracket may be fastened to the side surface facing the rear side of the vehicle and the lower surface. With this configuration, the front spring bracket can be firmly connected to the cross member.

The vehicle body structure according to one embodiment includes a pair of side rails extending in the fore-and-aft direction of the vehicle, a cross member extending in the width direction of the vehicle and connecting the pair of side rails, a pair of rear rails connected to a midpoint in the extension direction of the cross member and extending from the cross member to the rear of the vehicle, a leaf spring positioned outside the pair of rear rails in the width direction of the vehicle and supporting the rear axle of the vehicle, and a front spring bracket connecting the front end of the leaf spring to the cross member.

The vehicle body structure according to this aspect makes it possible to prevent the vehicle from becoming too heavy.

Various aspects of the present invention can prevent the vehicle from becoming too heavy.

1 is a plan view of a body structure including a suspension device according to one embodiment. FIG. 2 is a side view of the body structure shown in FIG. FIG. 2 is a plan view of the suspension device. FIG. 4 is an enlarged perspective view showing the periphery of a front spring bracket.

Embodiments of the present disclosure will now be described with reference to the drawings. In the following description, identical or equivalent elements will be given the same reference numerals, and redundant descriptions will not be repeated.

Figure 1 is a plan view showing a body structure including a suspension device according to one embodiment. Figure 2 is a side view of the body structure shown in Figure 1. The vehicle body structure 1 shown in Figures 1 and 2 is a structure applied to a large vehicle such as a truck. The vehicle is an electric vehicle that runs by driving a motor with battery power, such as a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. In the following description, the forward and backward directions of the vehicle are referred to as the fore-aft direction of the vehicle, and the left-right direction when the vehicle is viewed from the rear is referred to as the vehicle width direction.

As shown in FIG. 1, the body structure 1 includes a vehicle body frame 10 and a suspension device 30. The vehicle body frame 10 includes a pair of side rails 2, a pair of cross members 3, a pair of front rails 4, and a pair of rear rails 5. The pair of front rails 4 support a cab 8 in which the driver's seat of the vehicle is located, and the pair of side rails 2 and the pair of rear rails 5 support a cargo bed 9 of the vehicle.

The pair of side rails 2 are spaced apart from each other on the left and right sides and extend parallel to each other along the fore-aft direction of the vehicle. In one embodiment, the pair of side rails 2 are located in the center of the vehicle in the fore-aft direction, more specifically, between the front wheels 17 and rear wheels 18 of the vehicle.

The pair of cross members 3 extend in the vehicle width direction and connect the ends of the pair of side rails 2. The pair of side rails 2 and the pair of cross members 3 are made of long metal members, such as I-beams. A battery mounting area R1, which is a rectangular space, is formed between the pair of side rails 2 and the pair of cross members 3. A battery 21 that supplies power to drive the vehicle is mounted in the battery mounting area R1.

The pair of cross members 3 includes a cross member 3A disposed at the front and a cross member 3B disposed at the rear of the cross member 3A. A walk-through portion W that allows occupants to pass between the cab 8 and the cargo bed 9 may be formed on the cross member 3A.

The pair of front rails 4 are connected to the cross member 3A. The pair of front rails 4 are spaced apart in the vehicle width direction and extend parallel to each other from the cross member 3A toward the front of the vehicle. That is, the pair of front rails 4 are arranged forward of the pair of side rails 2. The distance between the pair of front rails 4 in the vehicle width direction is smaller than the distance between the pair of side rails 2 in the vehicle width direction. Therefore, the pair of front rails 4 are connected to a midpoint in the extension direction of the cross member 3A. The pair of front rails 4 are connected to cross members 11 and 12 that extend in the vehicle width direction. The cross member 11 connects the tips of the pair of front rails 4 to each other. The cross member 12 is arranged behind the cross member 11 and connects the pair of front rails 4.

Front wheels 17 are attached to the pair of front rails 4 via front axles 15. A front mounting area R2 is formed between the pair of front rails 4. In the front mounting area R2, electrical components such as a motor 22 and an inverter 23, as well as a cooling device 24 for cooling these electrical components, are mounted.

Between the pair of front rails 4 and the cross member 3A, upper and lower kick parts 6 are provided, which connect the pair of front rails 4 and the cross member 3A so that the pair of side rails 2 are positioned lower than the pair of front rails 4. The upper and lower kick parts 6 are connected to the rear ends of the pair of front rails 4, and are connected to the cross member 3A while continuously inclining downward as they approach the cross member 3A. By interposing the upper and lower kick parts 6 between the cross member 3A and the pair of front rails 4, the pair of cross members 3 and the pair of rear rails 5 are positioned lower than the pair of side rails 2. As a result, the cargo bed 9 is supported at a lower position, making it possible to increase the load capacity of the vehicle.

The pair of rear rails 5 are connected to the cross member 3B. The pair of rear rails 5 are spaced apart in the vehicle width direction and extend parallel to each other from the cross member 3B toward the rear of the vehicle. That is, the pair of rear rails 5 are arranged rearward of the pair of side rails 2. The distance between the pair of rear rails 5 in the vehicle width direction is smaller than the distance between the pair of side rails 2 in the vehicle width direction. Therefore, the pair of rear rails 5 are connected to a midpoint in the extension direction of the cross member 3B. The distance between the pair of rear rails 5 in the vehicle width direction may be the same as the distance between the pair of front rails 4 in the vehicle width direction. The pair of rear rails 5 are connected to the cross member 13 and the cross member 14 extending in the vehicle width direction. The cross member 13 connects the rear ends of the pair of rear rails 5 to each other. The cross member 14 is arranged in front of the cross member 11 and connects the pair of rear rails 5.

Rear wheels 18 are attached to the pair of rear rails 5 via rear axles 16. A rear mounting area R3 is formed between the pair of rear rails 5. In the rear mounting area R3, electrical components such as a junction box 25, an on-board charger 26, and a DC converter 27, as well as a cooling device 28 for cooling these electrical components, are mounted.

As described above, the length of the pair of cross members 3 in the vehicle width direction is longer than the length of the cross members 11, 12, 13, and 14. Therefore, the width of the battery mounting area R1 in the vehicle width direction is greater than the widths of the front mounting area R2 and the rear mounting area R3 in the vehicle width direction. In other words, the portion of the body frame 10 where the pair of side rails 2 are arranged is wider than the portion where the pair of front rails 4 and the pair of rear rails 5 are arranged.

Figure 3 is a plan view of the suspension device 30. The suspension device 30 is provided between the body frame 10 and the rear axle 16, and suppresses vibration of the body frame 10 during traveling. As shown in Figures 2 and 3, the suspension device 30 includes a pair of leaf springs 31, a pair of front spring brackets 32, a pair of rear spring brackets 33, and a pair of shock absorbers 34.

As shown in FIG. 3, the pair of leaf springs 31 are disposed on the outer sides of the pair of rear rails 5 in the vehicle width direction and extend in the front-rear direction of the vehicle. The leaf springs 31 support the rear axle 16 at their center in the front-rear direction via the support member 16a.

The front end 31a of the leaf spring 31 is connected to the cross member 3B via the front spring bracket 32. FIG. 4 is an enlarged perspective view of the periphery of the front spring bracket 32. As shown in FIG. 4, the cross member 3B has a hollow structure with a rectangular cross section including an upper surface 3u facing the upper side of the vehicle, a lower surface 3b facing the lower side of the vehicle, and a pair of side surfaces 3s facing in the front-rear direction of the vehicle. The front spring bracket 32 is bolted to the side surface 3s facing the rear side of the vehicle and the lower surface 3b of the pair of side surfaces 3s. The front spring bracket 32 also has a fixed shaft extending along an axis AX parallel to the extension direction (vehicle width direction) of the cross member 3B. The front end 31a of the leaf spring 31 is rounded to surround the fixed shaft of the front spring bracket 32 and is fastened to the front spring bracket 32 so as to be rotatable around the axis AX. That is, the front end 31a of the leaf spring 31 is rotatably connected to the cross member 3 via the front spring bracket 32.

As shown in FIG. 2, the pair of rear spring brackets 33 are disposed behind the pair of front spring brackets 32 and are fastened to the outer surfaces of the pair of rear rails 5. The rear end 31b of the leaf spring 31 is fastened to the rear spring bracket 33 via a shackle 35. The shackle 35 is rotatable relative to the rear spring bracket 33. That is, the rear end 31b of the leaf spring 31 is rotatably connected to the rear rail 5 via the rear spring bracket 33.

As shown in FIG. 3, a pair of shock absorbers 34 are provided between the pair of rear rails 5 and the rear axle 16. The shock absorbers 34 dampen vibrations of the leaf springs 31 caused by the up and down movement of the rear axle 16.

As described above, in the suspension device 30, the front end 31a of the leaf spring 31 is connected to the cross member 3B via the front spring bracket 32, and the rear end 31b of the leaf spring 31 is connected to the rear rail 5 via the rear spring bracket 33. Therefore, the load transmitted from the rear axle 16 to the leaf spring 31 is distributed and transmitted to the cross member 3B and the pair of rear rails 5. This prevents the load from concentrating on the pair of rear rails. As a result, the load transmitted to the connection C between the cross member and the pair of rear rails is reduced, making it possible to simplify the reinforcement of the connection C (see FIG. 3). This prevents the vehicle from becoming heavy.

In addition, in the above-described body structure 1, the distance between the pair of side rails 2 in the vehicle width direction is greater than the distance between the pair of front rails 4 in the vehicle width direction and the distance between the pair of rear rails 5 in the vehicle width direction. In other words, the portion where the pair of side rails 2 are arranged is wider than the portion where the pair of front rails 4 and the pair of rear rails 5 are arranged. This makes it possible to ensure a wide battery mounting area R1 formed between the pair of side rails 2, making it possible to mount a battery 21 with a relatively large capacity while maintaining the wheelbase of the vehicle. As a result, the vehicle's cruising range can be increased.

The front spring bracket 32 connects the leaf spring 31 to the cross member 3B so that the front end 31a of the leaf spring 31 can rotate around the axis AX parallel to the extension direction of the cross member 3B. When the leaf spring 31 is connected to the cross member 3B so that the front end 31a of the leaf spring 31 can rotate around the axis AX parallel to the extension direction of the cross member 3B, it is possible to position the fixed shaft of the front spring bracket 32 closer to the body frame 10 than when the front spring bracket 32 is fastened to the rear rail 5. By positioning the fixed shaft of the front spring bracket 32 closer to the body frame 10, the moment acting on the front spring bracket 32 is reduced. Therefore, the front spring bracket 32 can be simplified, and as a result, the weight of the vehicle can be further suppressed.

Although various embodiments of the suspension device and vehicle body structure have been described above, the invention is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the invention.

1...body structure, 2...side rail, 3...cross member, 3b...underside, 3s...side, 3u...upper surface, 5...rear rail, 10...vehicle frame, 16...rear axle, 30...suspension device, 31...leaf spring, 31a...front end, 31b...rear end, 32...front spring bracket, 33...rear spring bracket.

Claims (4)

A suspension device attached to a vehicle body frame including a pair of side rails extending in a front-rear direction of a vehicle, a cross member extending in a vehicle width direction of the vehicle and connecting the pair of side rails, and a pair of rear rails connected to a midpoint of the cross member in the extending direction and extending from the cross member to a rear of the vehicle,
a leaf spring disposed on an outer side of the pair of rear rails in the vehicle width direction and supporting a rear axle of the vehicle;
a front spring bracket connecting a front end of the leaf spring to the cross member;
Equipped with
The cross member has a hollow structure having a rectangular cross section including an upper surface facing an upper side of the vehicle, a lower surface facing a lower side of the vehicle, and a pair of side surfaces facing in a front-rear direction of the vehicle,
A suspension device , wherein the front spring bracket is fastened to one of the pair of side surfaces that faces the rear of the vehicle and to the lower surface . The suspension device according to claim 1, further comprising a rear spring bracket that connects the rear ends of the leaf springs to the pair of rear rails. The suspension device according to claim 1 or 2, wherein the front spring bracket connects the front end of the leaf spring to the cross member so that the front end of the leaf spring can rotate about an axis parallel to the extension direction of the cross member. A pair of side rails extending in a front-rear direction of the vehicle;
a cross member extending in a vehicle width direction of the vehicle and connecting the pair of side rails;
A pair of rear rails connected to the cross member at an intermediate position in the extending direction and extending from the cross member toward the rear of the vehicle;
a leaf spring disposed on an outer side of the pair of rear rails in the vehicle width direction and supporting a rear axle of the vehicle;
a front spring bracket connecting a front end of the leaf spring to the cross member;
Equipped with
The cross member has a hollow structure having a rectangular cross section including an upper surface facing an upper side of the vehicle, a lower surface facing a lower side of the vehicle, and a pair of side surfaces facing in a front-rear direction of the vehicle,
The front spring bracket is fastened to one of the pair of side surfaces that faces the rear of the vehicle, and to the underside , of a vehicle body structure.

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