JP7574040B2 - Vehicle rear structure - Google Patents

Description

The present invention relates to a rear structure of a vehicle, and in particular to a rear structure of a vehicle that is effective against load input from the rear.

Electric vehicles, including hybrid vehicles, may be equipped with important safety components such as a motor and a drive battery in the rear of the vehicle. Such vehicles require a rear structure that can protect important safety components against input loads from the rear, such as a rear-end collision. For example, the following Patent Document 1 discloses a rear structure of a vehicle with a range extender device equipped with a motor and an engine mounted in the rear. In this rear structure of the vehicle, a muffler that extends in the vehicle width direction is arranged behind the range extender device equipped with a motor and an engine, and when a load is input from the rear, the muffler is pushed by the rear subframe on which the range extender device is mounted and wraps around under the range extender device, thereby protecting important safety components such as the motor.

JP 2019-73122 A

However, the rear structure of the vehicle described in Patent Document 1 requires a complex and precise structure for the rear subframe and the like. Also, in order to prevent the input load from the rear from reaching important safety components, it is generally necessary to add strong reinforcing members or strengthen the body frame, which leads to increased vehicle weight and costs. Furthermore, if such measures cannot be applied, measures such as reducing the battery capacity will be necessary, which will prevent the desired performance from being obtained and will lead to a decrease in product appeal. In other words, a simple rear structure for a vehicle that can protect important safety components mounted in the rear is desired.

The present invention was made in consideration of the above problems, and its purpose is to provide a simple rear structure for a vehicle that can protect important safety parts mounted in the rear.

In order to achieve the above object, the rear structure of a vehicle of the present invention comprises:
In the rear structure of the vehicle,
The vehicle comprises a wheel having a tire and a rim, a side sill arranged in front of the wheel on the lower part of the vehicle body and on both outer sides in the vehicle width direction, extending in the fore-and-aft direction of the vehicle, and a muffler arranged to the rear of the wheel, the vehicle width outer portion overlapping at least the widthwise central region of the wheel when viewed from the rear of the vehicle, wherein a forward protruding portion is provided on the vehicle front side of the vehicle width outer portion of the muffler which protrudes forward of the vehicle, and the forward protruding portion overlaps with the wheel when viewed from the rear of the vehicle .

With this configuration, when a load is input from the rear, the muffler is moved forward of the vehicle by the abutting object from the rear and abuts against the wheel, and the wheel is further moved forward of the vehicle and abuts against the side sill. Generally, when a load is input from the rear of a vehicle, the load acts only on the rear side frame that forms the framework of the rear of the vehicle body, but with the above configuration, the input load from the rear is also distributed to the side sill, so large deformation of the side frame can be avoided. This makes it possible to avoid large deformation of the rear of the vehicle and protect important safety parts mounted in the rear of the vehicle.

With this configuration, when a load is input from the rear of the vehicle and the muffler comes into contact with the wheel, the forward protrusion of the muffler fits into a recess on the inner widthwise side of the wheel rim. Generally, the outer periphery of the rim is recessed on the inner widthwise side to accommodate the tire, and by the forward protrusion of the muffler fitting into this recess, the muffler is prevented from coming off the wheel to the inner or outer widthwise side of the vehicle when a load is input from the rear, and the wheel is reliably abutted against the side sill, so that the input load from the rear can be reliably distributed to the side sill.

A further configuration of the present invention is a braking force control device that controls the braking force of the wheels, and a rear load detection means that detects a load input to the vehicle from the rear, and the braking force control device is characterized in that it applies a braking force to the wheels when the rear load detection means detects a load input to the vehicle from the rear.

With this configuration, when a load input from the rear of the vehicle is detected, the rotation of the wheels is restricted, so that when the muffler comes into contact with the wheels, the muffler and the wheels are prevented from moving upward and downward as the wheels rotate, and the wheels can be reliably brought into contact with the side sill. In addition, in the event of a rear-end collision, the forward movement of the vehicle is restricted, so further collision with an object in front is avoided.

A further configuration of the present invention is characterized in that the vehicle width direction outer portion of the muffler has an insulating structure formed therein by laminating a combination of insulating material and a metal shielding plate that divides the inside of the muffler .

With this configuration, even if the outer portion of the muffler in the vehicle width direction is located on the outer side in the vehicle width direction compared to existing vehicles, the thermal impact on vehicle body components such as the bumper can be reduced by providing a heat insulating structure in that portion.

As explained above, according to the present invention, it is possible to avoid large deformations in the rear of the vehicle by distributing the input load from the rear of the vehicle to the side sills, thereby protecting important safety parts mounted in the rear without increasing weight or cost, and ensuring marketability.

1 is a side view of a vehicle rear portion showing a schematic configuration of an electric vehicle according to one embodiment to which the vehicle rear structure of the present invention is applied; FIG. 2 is a bottom view of the rear of the vehicle shown in FIG. 1 . FIG. 2 is a rear view of the muffler and rear wheels of the vehicle of FIG. 1 . 2 is a flowchart of a calculation process executed in the braking force control device of FIG. 1 . FIG. 4 is a bottom view showing a state in which a load is input from the rear to the vehicle shown in FIGS. FIG. 4 is a diagram showing a modified example of the muffler of FIG. 3 . FIG. 4 is a rear view showing a modified example of the muffler of FIG. 3 .

Below, an embodiment of the vehicle rear structure of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of the rear of the vehicle showing the schematic configuration of an electric vehicle to which the vehicle rear structure of this embodiment is applied, and FIG. 2 is a bottom view of FIG. 1. This electric vehicle is equipped with an engine and a motor generator (not shown) at the front of the vehicle as a driving source for driving the vehicle, and is equipped with a high-voltage, large-capacity driving battery 1 at the rear of the vehicle that supplies high-voltage, large-current power to the motor generator. For this driving battery 1, for example, a lithium-ion battery or the like is used, which can be charged with regenerative power when the motor generator is used as a generator.

Rear wheels 2 are arranged on both the left and right sides of the rear of the vehicle (both sides in the vehicle width direction). The rear wheels 2 are equipped with a tire 3 on the outer periphery of the wheel and a rim 4 that supports the inner periphery of the tire 3, and the rim 4 is provided on the outer periphery of a wheel that is journalled on, for example, the rear axle. As is well known, the tire 3 is made of an elastic body such as rubber and is formed in a circular tube shape with an open radial inner part, and the rim 4 is recessed on the inner side in the width direction so as to accommodate the radial inner part of the tire 3 (see Figure 6). With the radial inner part closed by the rim 4, air (or other gas) is pressurised and injected into the inside of the tire 3 to form a pneumatic tire.

Rear side frames 5 extending in the longitudinal direction of the vehicle are disposed on the inner side of the left and right rear wheels 2 in the vehicle width direction, and their rear ends are connected by a rear bumper beam 6. The rear side frames 5 are connected to floor side frames 8 extending in the longitudinal direction of the vehicle on both sides of the vehicle width direction in the lower part of the passenger compartment via kick-up sections 7 located forward of the rear wheels 2 and on the inner side of the vehicle width direction. The driving battery 1 is mounted in a battery frame (not shown) so as to be stored between the left and right rear side frames 5.

A side sill 9 is disposed in front of the rear wheels 2, on the outer side of the floor side frame 8 in the vehicle width direction, and extends in the vehicle front-rear direction. The side sill 9 is literally the threshold of the vehicle compartment, disposed below the side door, and although it is not always counted as a major skeletal member, it is a strength member that protects the vehicle compartment. The side sill 9 generally extends between the wheelhouse of the front wheels (not shown) and the wheelhouse of the rear wheels 2.

In this embodiment, an engine is mounted at the front of the vehicle, and its exhaust pipe 10 extends toward the rear of the vehicle and branches off at the rear of the vehicle, with a muffler 11 installed in each of the branches. The muffler 11 reduces the pressure and temperature of the exhaust by gradually expanding the engine exhaust and interfering with pressure waves. Such exhaust mufflers are sometimes called silencers, but here they will be referred to as mufflers 11.

In this embodiment, as shown in the rear view of FIG. 3, the muffler 11 is arranged and configured so that the outer portion in the vehicle width direction overlaps with the central region in the width direction of the rear wheel 2. The entire muffler 11, including the outer portion in the vehicle width direction, is integrated as the muffler 11, but the left end (outer portion in the vehicle width direction) of the muffler 11 shown in FIG. 3 does not function as the exhaust muffler described above, and only the outer shell (wrapped) portion is covered with a metal plate to form a heat-insulating structure 13. In this embodiment, when a load is input from the rear as described later, the muffler 11 moves forward of the vehicle and abuts against the rear wheel 2, so that the muffler hanger 12 that suspends the muffler 11 from the vehicle body is arranged at the outer portion in the vehicle width direction so as not to hinder the forward movement. In addition, a rear wheelhouse liner (fender liner) (not shown) is interposed between the muffler 11 and the rear wheel 2.

The electric vehicle of this embodiment is also provided with a braking force control device 14 that controls the braking force of each wheel. This braking force control device 14, like an anti-lock brake device or a vehicle behavior control device, is capable of controlling the braking force of each wheel by adjusting the braking fluid pressure of each wheel, and can apply braking force to each wheel even when the driver is not depressing the brake pedal. Note that instead of a configuration that adjusts the braking fluid pressure, if each wheel is equipped with an electric brake device, it is also possible to control the braking force of each wheel by adjusting the operating amount (operating state) of an electric motor that applies the braking force.

The braking force control device 14 is equipped with a processing unit with advanced computing capabilities. This processing unit is constructed as a computer system such as a microcomputer, and therefore, like existing computer systems, the braking force control device 14 is configured with, for example, a storage device that stores a processing program, and an input/output device for reading sensor signals from the load sensor 15 (described later) and for communicating with other control devices.

The electric vehicle of this embodiment is also provided with a load sensor (rear load detection means) 15 that detects a load input to the vehicle from the rear. This load sensor 15 is composed of, for example, an acceleration sensor disposed near the rear bumper. This load sensor 15 is for detecting a rear load of a magnitude that occurs, for example, in a rear-end collision of the vehicle, and is used, for example, to determine whether to deploy an airbag. In this embodiment, as described below, it is also used to determine the braking force applied to each wheel by the braking force control device 14.

Figure 4 is a flowchart of the calculation process executed by the braking force control device 14. This calculation process is executed, for example, by timer interrupt processing at a preset predetermined sampling period. First, in step S1, it is determined from the output signal of the load sensor 15 whether or not a load has been input from the rear of the vehicle. If a load has been input from the rear, the process proceeds to step S2, and if not, the process returns.

In step S2, full braking control is performed on all wheels (maximum brake fluid pressure control) before returning.

According to this calculation process, if a load similar to that of a rear-end collision is input to the vehicle from the rear, all wheels will be fully braked.

Figure 5 is a bottom view of the muffler 11, rear wheel 2, and side sill 9 when a load of the magnitude of a rear-end collision is input to the vehicle from the rear. The figure shows only the left side of the vehicle. In the electric vehicle of this embodiment, when a load of the magnitude of a rear-end collision is input to the vehicle from the rear, all wheels are fully braked as described above. When this load is input from the rear, the muffler 11 is moved forward of the vehicle by an abutting object from the rear, but the rear wheels 2 are located in front of the vehicle, and the outer parts of the muffler 11 in the vehicle width direction overlap with the central region of the rear wheels 2 in the rear view of the vehicle, so the muffler 11 abuts against the rear wheels 2. When the muffler 11 and the rear wheels 2 are further moved forward of the vehicle by an abutting object from the rear, i.e., the input load, the rear wheels 2 abut against the side sill 9. As described above, the side sill 9 is a strength member that protects the passenger compartment, so the rear wheels 2 abut against the side sill 9, dispersing the input load from the rear to the side sill 9.

In a typical vehicle, the muffler 11 does not overlap the rear wheel 2 when viewed from the rear of the vehicle, or overlaps only slightly. In this state, even if the muffler 11 moves forward of the vehicle due to an input load from the rear, the muffler 11 does not abut the rear wheel 2, or even if it does abut, it is moved diagonally inward in the vehicle width direction, and as a result, the rear wheel 2 is rarely moved forward of the vehicle due to the abutment of the muffler 11. In this case, the input load from the rear acts almost entirely on the rear side frame 5, which causes the rear side frame 5 to deform significantly. In addition, in the case of a rear-end collision of the vehicle, the rear wheel 2 may be moved forward of the vehicle by the impact object. However, even in this case, the impact object moves the rear wheel 2 forward of the vehicle while significantly deforming the rear side frame 5, so that a large deformation of the rear side frame 5 cannot be avoided. In an electric vehicle in which the driving battery 1 is mounted so as to be stored between the left and right rear side frames 5 as in this embodiment, it is difficult to avoid damage to the driving battery 1, which is an important safety component.

In contrast, in the electric vehicle of this embodiment, which can distribute the input load from the rear to the side sill 9 via the muffler 11 and the rear wheel 2, it is possible to avoid large deformation of the rear side frame 5 due to the input load from the rear, and this makes it possible to protect the driving battery 1, i.e., important safety parts, stored between the left and right rear side frames 5. In addition, since all wheels are fully braked when a load is input from the rear, it is possible to prevent the muffler 11 from deviating vertically from the rear wheel 2 due to, for example, the relative rotation of the rear wheel 2 and the muffler 11 after the rear wheel 2 abuts against the muffler 11, and thus the rear wheel 2 can be reliably abutted against the side sill 9. In addition, since all wheels are fully braked, that is, the vehicle is maintained in a stopped state, further collision of the vehicle with an object in front of it is avoided. Note that if the hanging position of the muffler 11 from the vehicle body by the muffler hanger 12 is on the inside in the vehicle width direction, there is a risk that the muffler 11 will rotate and move inward in the vehicle width direction around the hanging position. In response to this, the muffler 11 is suspended from the vehicle body by the muffler hanger 12 on the outer side in the vehicle width direction, so that the muffler 11 can be reliably brought into contact with the rear wheel 2 when a load is applied from the rear.

6 is a bottom view showing a modified example of the muffler 11 of this embodiment, showing only the left side of the vehicle. In this muffler 11, a forward protruding portion 16 that protrudes forward of the vehicle is provided on the vehicle front side of the outer part in the vehicle width direction. This forward protruding portion 16 is formed, for example, by bending a metal plate that constitutes the outer shell of the muffler 11. As described above, the outer part in the vehicle width direction of the muffler 11 of this embodiment overlaps up to the central region in the vehicle width direction when viewed from the rear of the vehicle, so that when a load is input from the rear, the forward protruding portion 16 formed on the outer part in the vehicle width direction of the muffler 11 enters the recess on the inner side in the width direction of the rim 4 as shown in the same figure. For example, when an input load from the rear acts toward the inside in the vehicle width direction, if the front surface of the muffler 11 is flat, the muffler 11 will slip on the contact surface of the tire 3 of the rear wheel 2 and move inward in the vehicle width direction, which may result in the muffler 11 deviating from the rear wheel 2 and making it impossible to abut the rear wheel 2 against the side sill 9. In contrast, if the forward protrusion 16 of the muffler 11 fits into the recess on the inside of the rim 4 in the width direction, the two are prevented from escaping inward or outward in the vehicle width direction, and as a result, the rear wheel 2 can be reliably abutted against the side sill 9.

In addition, in this embodiment, the outer portion in the vehicle width direction of the muffler 11, which will be positioned further outboard in the vehicle width direction than existing vehicles, is made of a heat insulating structure 13. As described above, the muffler 11 has the effect of lowering the temperature of the exhaust gas, so the muffler 11 itself is prone to becoming hot. On the outer side in the vehicle width direction at the rear of the vehicle, there are vehicle body components that are susceptible to heat effects, such as a plastic rear bumper. By arranging the heat insulating structure 13 on the outer portion in the vehicle width direction of the muffler 11 for these vehicle body components that are susceptible to heat effects, it is possible to reduce the thermal effects on these vehicle body components.

Fig. 7 is a rear view showing a modified example of the muffler 11 of this embodiment. In the muffler 11 of Fig. 3, the outer side of the functional part as an exhaust muffler in the vehicle width direction is covered with a metal plate, and the hollow part is made into a heat insulating structure 13. In the muffler 11 of Fig. 7, for example, an individual heat insulating material 17 is stored in the outer part of the press muffler in the vehicle width direction, and the heat insulating material 17 and the metal plate covering it constitute the heat insulating structure 13. With such a heat insulating structure 13, it is possible to reduce the thermal influence on the vehicle body components in the rear part of the vehicle, similarly to the muffler 11 of Fig. 3. Also, for example, a combination of such a heat insulating material 17 and a metal shielding plate that divides the inside of the muffler 11 in the vehicle width direction may be laminated.

In this manner, in the vehicle rear structure of this embodiment, the outer portion of the muffler 11 in the vehicle width direction is overlapped up to the central region in the width direction of the rear wheel 2, so that when a load is input from the rear, the muffler 11 moves forward of the vehicle and abuts against the rear wheel (wheel) 2, and the rear wheel 2 moves forward of the vehicle and abuts against the side sill 9. In existing vehicles, when a load is input from the rear of the vehicle, the load acts only on the rear side frame 5 that forms the framework of the rear of the vehicle body, but in the rear structure of this embodiment, the input load from the rear is also distributed to the side sill 9, so large deformation of the rear side frame 5 can be avoided. Therefore, when a load is input from the rear, it is possible to avoid large deformation of the rear of the vehicle, and it is possible to protect the important safety parts mounted on the rear of the vehicle, namely the driving battery 1.

In addition, by providing a forward protrusion 16 that protrudes forward of the vehicle on the vehicle front side of the outer side in the vehicle width direction of the muffler 11, when a load is input from the rear of the vehicle and the muffler 11 abuts against the rear wheel 2, the forward protrusion 16 of the muffler 11 fits into a recess on the inner width direction of the rim 4 of the rear wheel 2. The outer periphery of the rim 4 has a recess on the inner width direction to accommodate the tire 3, and by the forward protrusion 16 of the muffler 11 fitting into this recess, the muffler 11 is prevented from coming off the rear wheel 2 to the inner or outer width direction of the vehicle when a load is input from the rear, and the rear wheel 2 is reliably abutted against the side sill 9, so that the input load from the rear can be reliably distributed to the side sill 9.

In addition, when the load sensor (rear load detection means) 15 detects a load input from the rear of the vehicle, the braking force control device 14 applies a braking force to the wheel to restrict rotation, so that when the muffler 11 comes into contact with the rear wheel 2, the muffler 11 and the rear wheel 2 are prevented from moving away from each other in the vertical direction due to the rotation of the rear wheel 2, and the rear wheel 2 can be reliably brought into contact with the side sill 9. In addition, in the event of a rear-end collision, forward movement of the vehicle is restricted, so further collision with an object in front is avoided.

In addition, even if the vehicle width direction outer portion of the muffler 11 is located on the outer side in the vehicle width direction compared to existing vehicles, the thermal impact on vehicle body components such as the bumper can be reduced by providing a heat insulating structure 13 on the vehicle width direction outer portion.

The above describes the vehicle rear structure according to the embodiment, but the present invention is not limited to the configuration described in the above embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, the above embodiment describes only an example in which the vehicle rear structure of the present invention is applied to an electric vehicle such as a hybrid vehicle, but the vehicle rear structure of the present invention can be applied to any type of vehicle equipped with a muffler 11.

1. Drive battery (important safety component)
2 Rear wheel 3 Tire 4 Rim 5 Rear side frame 9 Side sill 11 Muffler 13 Heat insulating structure 14 Braking force control device 15 Load sensor (rear load detection means)
16 forward protrusion

Claims (4)

In the rear structure of the vehicle,
A wheel having a tire and a rim;
A side sill is disposed in front of the wheels on both outer sides of a lower portion of a vehicle body in a vehicle width direction and extends in a vehicle front-rear direction;
a muffler disposed behind the wheel, the muffler having an outer portion in a vehicle width direction overlapping at least a central region in the width direction of the wheel as seen from the rear of the vehicle ;
A forward protruding portion that protrudes forward of the vehicle is provided on a vehicle width direction outer side of the muffler,
A rear structure for a vehicle , wherein the forward protrusion overlaps with the wheel when viewed from the rear of the vehicle . a braking force control device that controls the braking force of the wheels;
a rear load detection means for detecting a load input from the rear of the vehicle,
2. The rear structure of a vehicle according to claim 1 , wherein the braking force control device applies a braking force to the wheels when the rear load detection means detects a load input to the vehicle from the rear. 3. The vehicle rear structure according to claim 1, wherein the vehicle width direction outer portion of the muffler has an insulating structure formed by laminating a combination of insulating material and a metal shielding plate that divides the inside of the muffler . the vehicle includes an engine and a motor generator as a drive source, and a drive battery at a rear of the vehicle that supplies power to the motor generator;
4. The vehicle rear structure according to claim 1, wherein a rear end edge of the muffler protrudes rearward in the vehicle front-rear direction beyond the drive battery.

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