JPH04368288A - Automotive rear body structure - Google Patents

Abstract

PURPOSE:To apply reinforcement to a rear suspension member so that any deformation caused by a pump from behind hardly befall to a fuel tank as possible. CONSTITUTION:A fuel 32 is provided in front of a rear suspension member 5, and a spare tire pan 33 to house a spare tire under a horizontal condition is provided behind it. Reinforcement 41 is installed so as to increase bending rigidity of the edge part situated on the wheel support member side in the rear suspension member 5 beyond the bending rigidity of its central part. Vehicle body installation units 5A and 5B for pivotally fixing units 14 and 27 of a suspension arm 6 and the suspension arm 6 to a vehicle body are also provided in the edge part situated on the wheel support member 2 side. Even if the spare tire in its horizontal posture is pushed forward by a bump from behind, its energy is absorbed, so that even of the rear suspension member is largely deformed, the deformation can be prevented from befalling to the fuel tank.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to the rear body structure of an automobile, and more specifically, to suppress the deformation of a suspension member in a rear suspension system in the event of a rear collision, thereby reducing damage to mounted parts and mounting devices. This relates to the rear body structure.

0002

[Prior Art] In an automobile suspension system,
Recently, a multi-link method is often adopted. Such a suspension device is supported by suspension members arranged to extend in the left-right direction of the vehicle body. The suspension member needs to pivotally support many suspension links, and a pivot portion for this purpose is provided. When each link is attached to such a pivot joint, if the suspension member is of a welded structure obtained by pressing a steel plate, the rigidity can be partially varied. Incidentally, as described in Japanese Utility Model Publication No. 2-26734, a fuel tank is sometimes mounted immediately in front of a suspension member disposed at the rear of the vehicle body. In such a case, if a large impact force is applied to the suspension member from behind due to a rear-end collision, the suspension member is deformed and a portion of the suspension member protrudes forward, making it easy to damage the fuel tank.

0003

[Problem to be solved by the invention] For example, when a fuel tank is mounted in front of a suspension member placed at the rear of the vehicle body, and a spare tire is stored approximately horizontally behind it. There is concern that if a large impact force is applied from behind, such as in a rear-end collision, the spare tire may be pushed forward, resulting in severe deformation of the suspension member. The suspension member is usually fixed to the vehicle body on its left and right sides, and pivot parts such as suspension arms are formed at both ends. Therefore, when a force pushing the suspension member forward is applied due to a rear collision or the like, the central portion where the vehicle body attachment portion does not exist deforms and tries to move forward. At this time, a large local bend occurs on the side of the suspension member that is closer to the center of the vehicle body mounting portion, and the center portion bends from this point into a substantially V-shape. If such deformation occurs, the tip of the bend will hit the fuel tank located in front of the vehicle, and in severe cases, the fuel tank may be damaged. Therefore, even if the suspension member deforms by absorbing impact energy in the event of a rear collision, it is necessary to prevent the deformation from reaching the fuel tank. Incidentally, loads act on the suspension members from the lateral and vertical directions while the vehicle is running, but if the rigidity of the suspension members is low, the entire suspension system is likely to be vibrated.
Noise and vibration will increase. Furthermore, the stability of the suspension device also deteriorates, making it impossible to obtain good steering stability. Therefore, a certain degree of strength and high rigidity are required, but if they are too strong, they will be more likely to break when subjected to an impact load. Therefore, it is desirable to take care to ensure the rigidity while keeping the deformation to a gentle level. The present invention was made in view of the above problem, and its purpose is to allow the structure of the rear suspension member to deform to absorb energy due to a rear collision, but to prevent the deformation from reaching the fuel tank. The rear suspension member itself has been reinforced with reinforcement that minimizes the amount of force that is applied to it, ensuring the necessary rigidity while also protecting the fuel tank and preventing input loads from suspension arms, etc. To provide a rear body structure for an automobile in which a suspension member exhibits sufficient rigidity to suppress vehicle body vibration and noise.

0004

SUMMARY OF THE INVENTION The present invention is applied to a rear vehicle body structure that includes a suspension member that supports a suspension arm in a suspension device mounted on a vehicle body. Its features include, as shown in FIGS. 1 and 2, a fuel tank 32 is arranged in front of the rear suspension member 5 arranged in the vehicle width direction;
A spare tire pan 33 is installed behind the rear suspension member 5 to store a spare tire 35 (see FIG. 3) in a horizontal state. A reinforcement 41 is attached that makes the bending rigidity of the end portion of the rear suspension member 5 located on the wheel support member 2 (see FIG. 5) side higher than that of the center portion of the rear suspension member 5. Further, the end portion located on the wheel support member 2 side is provided with vehicle body mounting portions 5A, 5B for fixing the suspension arm pivot portions 13, 14, 27 and the suspension arm 6 to the vehicle body. The above reinforcement 41 is
It is preferable to form it on the front edge 37 of the rear suspension member 5. The rear suspension member 5 consists of an upper panel 5P (see FIG. 8) and a lower panel 5Q, both of which are welded to form a closed cross section 5a inside.
It is arranged so that it is welded inside Q and forms a small closed cross section 5b.

[0005]

[Operation] In front of the rear suspension member 5,
A fuel tank 32 is arranged, and a space for a spare tire pan 33 is secured at the rear. In such a vehicle body, when the vehicle body is to be lowered from a design standpoint, the spare tire 35 is housed and installed substantially horizontally, and the spare tire pan 33 for this purpose is also horizontally disposed. In particular, if a multi-link system is used as the suspension system, it is necessary to secure a fairly large volume for the suspension wheel house.
The restrictions are getting bigger and bigger. This rear suspension member 5 includes a substantially U-shaped bracket 27 to which the upper arm 7 (see FIG. 5) is pivotally attached, a support bracket 13 to which the lower arm front 6A is pivotally attached, and furthermore,
Bracket 1 for attaching the link of stabilizer 12
4 is also provided, and the end of the rear suspension member 5 serves as a pivot point for a suspension arm 6. As a result, if there is a rear collision with a fairly large impact force, the spare tire 35 is pushed forward, thereby deforming the rear suspension member 5. A reinforcement 41 for crushing control is attached to the rear suspension member 5 in order to realize gentle deformation of the rear suspension member 5. The position where this reinforcement 41 is provided on the rear suspension member 5 is the front part of the rising part 5m, and is located at the bent part 36 where the arm part 5M extends from the main body part 5N. In this way, the bent portion 36
If the rigidity of the main body 5N is increased, even if the main body 5N is pushed forward, the opening angle α at the bent portion 36 is likely to be maintained, and as a result, the main body 5N forms a gentle circular arc as indicated by the two-dot chain line 42, for example. It becomes a deformation. In the case of such arcuate deformation, the amount of forward movement of the front edge 37 of the main body portion 5N is small, and it is extremely unlikely that the rear suspension member 5 approaches and hits the fuel tank 32. Moreover, even if it hits, it will be a surface contact, and the influence on the fuel tank 32 can be reduced. That is, the bending rigidity at the bending portion 36 is increased by the reinforcement 41, and the bending stiffness at the bending portion 36 is increased so that the bending portion 36 does not bend as much as the angle β. Note that the bent portion 36 is formed between the main body portion 5N and the arm portion 5M.
The cross section of the reinforcement 41 is the connecting part between the two upper and lower panels 5 forming a closed cross section 5a.
A small closed section 5 formed at the lower corner of the front part of P, 5Q
b.

[0006]

[Effects of the Invention] According to the present invention, the reinforcement provided at the left and right ends of the rear suspension member at a position closer to the center of the vehicle body mounting portion prevents the spare tire in a horizontal position from being pushed forward by a rear collision or the like. too,
Energy from a rear collision is absorbed, preventing the rear suspension member from deforming and reaching the fuel tank. In addition, the suspension members have sufficient rigidity against input loads from suspension arms, etc., reducing vehicle body vibration and noise. When the reinforcement is formed on the leading edge of the rear suspension member, deformation of the rear suspension member is further reduced even if the fuel tank is located in the front. The rear suspension member consists of an upper panel and a lower panel, both panels are welded to form a closed cross section inside, and a reinforcement is welded to the inside of the lower panel to form a small closed cross section. If there is, deformation suppression can be more effectively promoted.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on drawings showing embodiments. FIG. 4 is a plan view of the rear suspension, which is symmetrical and only the right side is shown. The top of the diagram corresponds to the front side of the vehicle body. FIG. 5 is an elevational view thereof, and FIG. 6 is a view taken along the line A--A in FIG. In such a suspension device,
Hub support 2 as a wheel support member that supports rear wheel 1
are on the left and right (only one is shown), and its hub support 2
, 2, a sub-frame 5 serving as a rear suspension member is arranged so as to extend in the left-right direction of the vehicle body. As shown in FIG. 7, this subframe 5 consists of an upper panel 5P and a lower panel 5 that are made of pressed iron plate.
Q and welded together to form a closed cross section 5a that is approximately rectangular in cross section in the front-rear direction. Five links are used for such subframe 5,
It has a multi-link suspension system. Note that the subframe 5 has front and rear vehicle body attachment parts 5A and 5B.
(See FIG. 4), it is attached to a vehicle body frame (not shown) and supported at a total of four points on the left and right sides. As shown in FIG. 5, this sub-frame 5 has a rising portion 5m formed near the hub support 2, and as shown in FIG.
The portion marked A is a slightly thin arm portion 5M that protrudes forward. The main body portion 5N extends in the left-right direction including the vehicle body attachment portion 5B at the rising portion 5m.
is formed thicker than the arm portion 5M.

Since the suspension system in this example is for a front wheel drive vehicle, the rear suspension system does not include a differential gear unit. In such a suspension device, there are two lower arms 6, 6 connecting the subframe 5 and the hub support 2 attached to the rear wheel 1, as shown in FIG. 5, and an upper arm 7 above them. It is located. The lower arm 6 consists of a lower arm front 6A and a lower arm rear 6B, and the latter can also function as a steering tie rod when a four-wheel steering vehicle is used as described later. An upper trailing arm 3B and a lower trailing arm 3A are attached to the upper and lower parts of the hub support 2, respectively, and extend toward the front side of the vehicle body.
is supported by the vehicle body. As mentioned above, this example is a rear suspension used at the rear of a two-wheel steering vehicle that steers only the front wheels, and the lower arm rear 6B is connected to the ball joint 8 located at the rear of the subframe 5.
It is pivoted by connecting to. However, if a rear wheel steering gear unit 9 (indicated by a phantom line in FIG. 4) for four-wheel steering is connected to the ball joint 8, the rear wheels 1 will be in the same phase as the front wheels are being steered. It will also be possible to steer the vehicle and have it take opposite steering angles at low speeds. The lower end of a suspension damper 11 is attached to the pivot point 10 of the lower arm front 6A near the hub support 2, and the upper end of the suspension damper 11 is fixed to a suspension tower (not shown) of the vehicle body to buffer vehicle body vibrations. Can be done. Note that a stabilizer control link 12 that connects the right hub support 2 and the left hub support (not shown) extends left and right. This stabilizer is bent forward as shown in FIG. 4 at a location close to the rear wheel 1.
It is connected to a rod 12a extending vertically through a joint 12A shown in FIG. 6, and the upper end of the rod 12a is connected to the hub support 2 by a support portion 2f at the center of the hub support 2 in the vertical direction.

Incidentally, a support bracket 13 (see FIG. 5) made of sheet metal is attached to the lower part of the main body part 5N of the subframe 5 near the rear wheel 1, and one end of the lower arm front 6A mentioned above can swing freely. It is pivoted. The lower arm front 6A needs to have a desired anhedral angle and camber, and for this purpose, a support bracket 13 is attached to the lower part of the subframe 5 so as to project downward. This support bracket 13
A bridging bracket 14 as another metal fitting is attached so as to straddle the and subframe 5 and also has a reinforcing function. With this bridge bracket 14, the torsional rigidity of the support bracket 13 can be increased, and the load acting on the support bracket 13 can be dispersed by the bridge bracket 14, so that the weight of the support bracket 13 can be reduced. It is considered. Although not described in detail, the bridge bracket 14 is formed with two mounting surfaces 14a and 14b, as shown in FIG.
One mounting surface 14a is used to support the connecting rod 15 that connects the lower arm rear 6B to the left and right, or to support the rear wheel steering gear unit 9 for four-wheel steering when it is attached. be done. The other mounting surface 14b supports the intermediate portion of the control link 12 of the stabilizer described above. Note that these mounting surfaces 14a and 14b are formed at different positions and at different angles in order to make the mounting work less likely to occur.

The hub support 2 described above is made of die-cast aluminum, and the suspension member 5 is made of a pressed iron plate as described above. However, the five links that make up the suspension arms are all made of cast iron because the forces from the wheels act in the axial direction and large bending forces are applied to them. For example, to explain the lower arm front 6A of the lower arm 6, FIG.
As shown in FIG. 5, the left end boss portion 18 is a pivot point connected to a support bracket 13 shown in FIG. 5 and described later. On the other hand, the right end boss portion 19 has a ball joint 20 (Fig.
) is mounted in a caulking manner, and is pivoted to a support portion 2a, which will be described later, of the hub support 2 shown in FIG. 10 via its ball joint 20. moreover,
An intermediate boss portion serving as a pivot point 10 is formed close to the boss portion 19 of the lower arm front 6A, and is capable of supporting the lower end of the suspension damper 11 (see FIG. 5). The centers 18a, 10a, and 19a of each of the boss portions 18, 10, and 19 are located on a straight line 21 indicated by a dashed line, and although this linear arrangement is not shown, it is maintained even in a plan view. has been done. This is because the lower arm front 6A functions as a link, and the compressive force and tensile force acting on it are sufficient if they are applied as axial force, and the center 10a supporting the suspension damper 11 is aligned with the straight line 2.
If it deviates from 1, the lower arm front 6A will bend due to the lateral force applied from the suspension damper 11, but care has been taken to prevent this from happening.

FIG. 10 is an individual diagram of the hub support 2 fixed to the rear wheel 1 described above, which is integrally manufactured by die-casting aluminum or the like, and has support parts with suspension arms formed at various places. The figure is an elevational view when viewed from the center of the vehicle body toward the rear wheel 1. Referring also to FIG.
is rotatably mounted. The lower arm front 6A is connected to a ball joint 20 on the support section 2a at the lower center.
The support part 2 of the protruding part on the right side is attached through the
c, lower arm rear 6B is ball joint 2
Connected via 2. The upper arm 7 is attached to the support part 2d formed at the center part in the vertical direction,
An upper trailing arm 3 is attached to the top support portion 2e.
B is connected via a ball joint 23. The hub support 2 to which five links are attached in this way is
It is attached to the inside of the rear wheel 1 using three mounting seats 2A to 2C with bolts or the like, as shown in FIG. The above-mentioned support parts 2a to 2e, including the support part 2f that supports the stabilizer rod 12a, are provided in the vicinity of the rib 30 formed around the hub support 2 or so as to be continuous with the rib 30. The space between the ribs 30 is usually a thin web 31, and if necessary, a lightening hole is provided to ensure the overall strength and rigidity of the hub support 2 and to reduce the weight. There is. Therefore, the unsprung portion of the suspension is not heavy, and deterioration in steering followability is also avoided.

By the way, in FIG. 1, subframe 5
A fuel tank 32 is arranged in front of the vehicle, and a space for a spare tire pan 33 is secured in the rear. If you look at the arrangement in the front-back direction, it looks like Figure 3. The floor panel 34 is formed with unevenness, and the portion where the subframe 5 is located is raised. The rear part thereof is a recessed part as a spare tire pan 33 for storing a spare tire 35 horizontally. In addition, when the gear unit 9 for four-wheel steering is provided, it is installed at the position shown in the figure. In a car body with such an arrangement, if the car body is to be lowered from a design point of view, if it is impossible to store the spare tire 35 leaning up, it will have to be stored almost horizontally, and the spare tire pan will be 33 is also installed horizontally. In particular, when a multi-link suspension system is adopted, it is necessary to secure a considerably large volume of the suspension wheel house, which makes it increasingly difficult to store the spare tire 35 by leaning against it. As a result, in the event of a rear-end collision with a considerable impact force, the spare tire 35 is pushed forward, thereby deforming the subframe 5. Furthermore, if a box for a gear unit 9 for four-wheel steering is attached to the rear of the subframe 5, the deformation of the subframe 5 will be further exacerbated by its forward displacement. As shown in FIG. 1, the subframe 5 has two vehicle body attachment portions 5A and 5B on the left and right sides thereof.
Since it is fixed to the vehicle body, it deforms into a substantially U-shape with its center bent and protruding forward. If such deformation occurs, the top of the bend will hit the fuel tank 32 located in the front in a concentrated manner, and in severe cases, the fuel tank may be damaged. Therefore, even if the subframe 5 deforms by absorbing the impact energy in the event of a rear collision, it is necessary to prevent the deformation from reaching the fuel tank 32.

On the other hand, on the subframe 5, there is a substantially U-shaped bracket 27 for pivotally mounting the upper arm 7 (see FIG. 5).
, a support bracket 13 for pivotally connecting the lower arm front 6A, and a holding bracket 28 for attaching the link of the stabilizer 12 to the bridging bracket 14. It has become a department. For this reason, loads act on the subframe 5 from the lateral and vertical directions during driving, but if the rigidity of the subframe 5 is low, the entire suspension system is likely to be vibrated, causing noise and vibration. It gets bigger. Also, subframe 5
If the lateral rigidity of the vehicle is low, the stability of the suspension system will also deteriorate, and when considering steering stability, a certain level of strength and high rigidity are required. However, if this is too strong, it will easily break when subjected to an impact load. Therefore, it is preferable to take care to ensure the rigidity and to limit the deformation to a gentle level. For this purpose, a reinforcement 41 for crushing control is attached to the subframe 5 to achieve gentle deformation. This reinforcement 41 will be described in detail later, but the subframe 5
As shown in FIG. 1, the position provided is at the front of the rising portion 5m, and is located at the bent portion 36 where the arm portion 5M extends from the main body portion 5N. In other words, since there are vehicle body attachment parts 5A and 5B on the side of the hub support 2 from this bent part 36, it is firmly fixed to the vehicle body, but in the event of a rear collision, the impact force from the center rear part of the subframe 5 When received, the main body part 5N
attempts to deform using the bent portion 36 as a base point. If the rigidity of the bent portion 36 is low, the opening angle α of the bent portion 36 will be deformed to be small as the angle β, and the deformation of the subframe 5 will tend to become approximately V-shaped as described above. . However, if the rigidity of the bent portion 36 is increased, even if the main body portion 5N is pushed forward, the opening angle α at the bent portion 36 is likely to be maintained, and as a result, the main body portion 5N has a substantially V-shaped shape. For example, a gentle arc-shaped deformation as shown by the two-dot chain line 42 occurs. In the case of such an arcuate deformation, the amount of forward movement of the front edge 37 of the main body portion 5N will be along the broken line 43, which will form a substantially V-shape on both the left and right sides.
The occurrence of the subframe 5 hitting the fuel tank 32 is extremely rare. That is, the bending rigidity at the bent portion 36 is increased by the reinforcement 41, so that the bending portion 36 does not bend as much as the angle β described above. By the way, bending part 36
Furthermore, if the entire front edge 37 of the main body portion 5N is reinforced, the reinforcing effect at the bent portion 36 will be weakened, and the weight of the subframe 5 will increase. Therefore, it is necessary to improve the rigidity in order to prevent damage to the fuel tank 32 due to rear collisions only at effective locations where the deformation form is known, and the reinforcement 41 is installed at such locations. It has been subjected. When deformation of the main body portion 5N is suppressed in this manner, the influence on the suspension device is reduced, and damage to the vehicle body as a whole can be reduced. Note that the position of the bent portion 36 in the vertical direction is as shown in FIG. 2, since the arm portion 5M is located slightly lower than the rising portion 5m.
It is located at the bottom in elevation.

The above-mentioned bent portion 36 is a connecting portion between the main body portion 5N and the arm portion 5M, and its cross section is divided into two upper and lower panels 5P forming a closed cross section 5a of the subframe 5, as shown in FIG. , 5Q, with a small closed cross section 5b formed at the lower corner portion. The closed cross section 5b is formed of a reinforcement 41 pressed into a substantially dogleg shape, and the reinforcement 41 is attached in advance to the inner surface of the lower panel 5Q by welding or the like, and the lower panel 5Q in this state is It is integrated with the upper panel 5P by welding. By the way, the end faces 46 of panels 5P and 5Q
, 47 is overlapped with the flange 48 of the reinforcement 41, so that the lower panel 5Q can be backed up when the end face 46 is welded to the end face 47. In addition, as shown in FIG. 7, the upper panel 5P and the lower panel 5Q generally have flanges 5p and 5q formed therein.
By spot welding or the like, it is possible to improve the ease of assembly and to increase the torsional rigidity of the subframe 5. However, no flange is provided on the front surface 37a of the front edge 37 of the main body portion 5N, and the end surfaces 46 and 47 of both panels 5P and 5Q are overlapped. By doing so, even if the main body portion 5N deforms as described above and approaches the fuel tank 32, surface contact will occur and the flange will avoid piercing the wall of the fuel tank 32.

As can be seen from the above explanation, in the rear suspension member, energy due to a rear collision is absorbed by crushing control by reinforcement. As a result, even if the rear suspension member is deformed due to a rear collision, it is possible to suppress the deformation from extending to the fuel tank as much as possible. This reinforcement also provides sufficient rigidity to the suspension members, making it possible to suppress vehicle body vibration and noise.

[Brief explanation of drawings]

FIG. 1 is an enlarged plan view showing a reinforcement attached to a bent portion of a rear suspension member located immediately behind a fuel tank.

[Figure 2] Enlarged elevational view of the rear suspension member with reinforcement attached.

[Figure 3] A layout diagram of the fuel tank, rear suspension member, and spare tire pan in the longitudinal direction of the vehicle body.

[Fig. 4] A plan view of the right half of the rear suspension.

[Fig. 5] Elevation view of the right half of the rear suspension.

FIG. 6 is a view taken along line A-A in FIG. 5.

FIG. 7 is a sectional view taken along line BB in FIGS. 1 and 4. FIG.

8 is a sectional view taken along the line C-C in FIG. 1;

[Figure 9] Single front view of lower arm front.

[Fig. 10] Elevation view of a single hub support.

[Explanation of symbols]

2...Hub support (wheel support member), 5...Subframe (rear suspension member), 5A, 5B...Vehicle body attachment part, 5P...Upper panel, 5Q...Lower panel,
5a...closed section, 5b...small closed section, 6...lower arm (suspension arm), 13, 14, 27...pivot part (bracket), 32...fuel tank, 33...spare tire pan, 35...spare tire, 37... Leading edge, 41...Reinforcement.

Claims (3)

[Claims] Claim 1: A rear vehicle body structure including a suspension member that supports a suspension arm in a suspension device mounted on a vehicle body, wherein a fuel tank is disposed in front of the rear suspension member disposed in the vehicle width direction, and the rear A spare tire pan for storing a spare tire in a horizontal state is installed behind the suspension member, and the bending stiffness of the end of the rear suspension member located on the wheel support member side is calculated from the bending stiffness of the center part of the rear suspension member. A reinforcement is attached to make the suspension arm higher than the vehicle body, and a pivot portion of the suspension arm and a vehicle body mounting portion for fixing the suspension arm to the vehicle body are provided at the end located on the wheel support member side. Rear body structure of a car. 2. The rear body structure of an automobile according to claim 1, wherein the reinforcement is formed at a leading edge of a rear suspension member. 3. The rear suspension member includes an upper panel and a lower panel, both of which are welded to form a closed section inside, and the reinforcement is welded to the inside of the lower panel to form a small cross section. The rear body structure of an automobile according to claim 1, wherein the rear body structure of an automobile has a closed cross section.