JP2010023716A - Lower structure of automobile side door - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lower structure of an automobile side door, which is superior in collision safety with respect to side collisions, even if a reinforcing member such as door waist reinforcement is omitted, and which has light-weight and is easy to assemble. <P>SOLUTION: The lower structure of the automobile side door 1a is provided with an inner panel 2 arranged with respect to an outer panel 3, and the inner panel 2 is constituted of an aluminum alloy panel in a thickness range of 1 to 4 mm, and in the upper part of the inner panel 2; and a rib 10 having a recessed and protruded cross sectional shapes is formed integrally, by molding of the inner panels themselves so as to reinforce the upper part instead of the door waist reinforcement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lower structure of an automobile side door that can cope with a side collision (side collision) of an automobile, has excellent collision safety, is lightweight, and can be easily assembled.

  The lower structure of a typical conventional automobile side door is shown in FIGS. 8 is a perspective view of the lower structure of the automobile side door, and FIG. 9 is a cross-sectional view taken along line AA of FIG. 8 and 9, in the lower structure 100 of the automobile side door, an inner panel 101 that constitutes the passenger compartment side is disposed with respect to the outer panel 102 that constitutes the side surface of the vehicle body. The inner panel 101 and the outer panel 102 form a box-type hollow structure having an internal space 105. As a result, even when a load (collision energy) due to a side collision from the side of the vehicle body (left side in the figure) indicated by the arrow direction in FIG. 9 is applied, the necessary rigidity and strength as the lower structure of the automobile side door are reduced. Can be secured.

  Here, according to the safety standard for side collision, even if the speed of side collision increases, the side door should not be greatly deformed and enter the passenger compartment to impair the safety of passengers in the passenger compartment. For this reason, on the upper part of the door inner panel 101, a door waist reinforcement (or reinforcement upper) 103 is provided as a reinforcing member for reinforcing the upper side of the lower structure of the automobile side door.

  This door waist reinforcement 103, together with the door beam 104 that reinforces the lower side of the lower structure of the automobile side door, the lower structure of the automobile side door is greatly deformed by a side collision and enters the vehicle interior, thereby impairing the safety of passengers in the vehicle interior. It plays an important role in preventing this. That is, the door beam 104 protruding from the side of the vehicle body is responsible for absorbing the collision energy in the first half of the side collision. Next, the door waist reinforcement 103 located closer to the passenger compartment is responsible for absorbing the collision energy in the second half of the side collision.

  The door waist reinforcement 103 is usually formed separately from the door inner panel 101 by press molding or the like, and a member manufactured by molding into a desired panel shape is formed on the door inner panel 101 by a method such as welding or rivet joining. Used by wearing. However, such a reinforcing method requires a manufacturing cost for press-molding the waist reinforcement 103 as a separate part, increases management costs due to an increase in the number of parts of the lower structure of the automobile side door, welding and rivet joining, etc. There are problems such as an increase in the joining cost. Also, in the case of a side collision, depending on the magnitude of the collision energy, these joints may be damaged, and the lower structure of the side door of the automobile will be greatly deformed and enter the passenger compartment, impairing the safety of passengers in the passenger compartment. There was a problem of lowering.

  On the other hand, in recent years, with respect to global environmental problems caused by exhaust gas and the like, improvement in fuel consumption has been pursued by reducing the weight of the body of a transport aircraft such as an automobile. For this reason, the application of lighter aluminum alloy materials such as rolled plates and extruded shapes, in place of steel materials that have been used in the past, is increasing especially for automobile bodies. Of these, the outer panel (outer plate) and inner panel (inner plate), which are substructures of automobile side doors, are also used for Al-Mg-Si AA to JIS 6000 (hereinafter simply referred to as 6000) and Al The use of aluminum alloy plates such as -Mg AA to JIS 5000 (hereinafter simply referred to as 5000) is being studied.

  However, in the example in which the inner panel and the outer panel are aluminum alloy plates (panels), the plate thickness is reduced to, for example, 1.2 mm or less in order to reduce the weight. In order to cope with side collisions, which have become particularly stringent in recent years under such thinning, the above-described doors of the lower structure of the automobile side doors are required to ensure the rigidity and strength of the doors. In addition to the waist reinforcement 103 and the door beam 104 that reinforces the lower part in FIG. 9, more reinforcing materials are required. In other words, despite the desire to reduce the number of parts of the lower structure of the automobile side door, the door waist reinforcement 103 could not be omitted from the viewpoint of safety and strength of side collision.

  For this reason, even if the inner panel is made of an aluminum alloy, the number of joints such as welding and self-piercing rivets associated with the installation of such many reinforcing materials increases, and the labor for the joint also increases. Moreover, the weight increase accompanying installation of a reinforcing material also impairs the advantage of weight reduction using an aluminum alloy. Furthermore, if there are many joints, as described above, depending on the magnitude of the collision energy, these joints may be damaged and the lower structure of the automobile side door may be greatly deformed and enter the vehicle interior, as described above. There are actually problems of safety reduction, such as compromising the safety of passengers.

  In contrast, the present inventors have proposed an aluminum alloy inner panel for automobile side doors that satisfies the necessary strength and rigidity to cope with a side collision, is excellent in collision safety, is lightweight, and is easy to form and assemble. I have done it. For example, in Patent Document 1, an inner panel of a side door of an automobile is an aluminum alloy plate made of a relatively thick plate, and a rectangular large hollow portion ( We proposed an example with space. Further, in Patent Document 2, an aluminum alloy sheet-formed panel is overlapped on the vehicle compartment side and the outer panel side to form an inner panel, and a closed cross-section space is formed at both the inner panel central portion and the peripheral portion. Proposed.

In these Patent Documents 1 and 2, a deep (a door thickness is ensured) cross-sectional space that can cope with a side collision can be formed in the center part and the peripheral part of the inner panel. For this reason, the strength and rigidity of the inner panel's central part and peripheral part can be greatly improved, and it is not necessary to use many reinforcing materials as in the past, and it can cope with side collisions where standards are becoming stricter. Can do. Moreover, the large shaping | molding depth required for an inner panel is securable by thickening a shaping | molding panel or overlapping two shaping | molding panels. Therefore, it is possible to produce an aluminum alloy inner panel having an inner panel forming depth (door thickness) that can solve the problem of the aluminum alloy thin plate that is difficult to press-form compared to a steel plate and can cope with the side collision. it can.
JP 2006-96179 A JP 2006-306157 A

  In the side collision test based on the safety standard for side collision described above, a carriage having a barrier at the tip is caused to collide at about 50 km / h on the side of the automobile body. In such a side collision test, an impact load is applied to the door panel as well as a vehicle body skeleton member such as a B-pillar of an automobile body, and the side door exhibits deformation that intrudes in the direction of the passenger compartment.

  Here, in the proposed change to the side impact test of Euro-NCAP, a third-party evaluation on vehicle safety in Europe that was recently announced, test conditions were further increased in order to make vehicle safety standards more stringent in side impacts. It is getting strict. For example, the weight of the cart used for the test is significantly increased from the conventional 950 kg to 1500 kg, and the aluminum honeycomb in the portion of the barrier in front of the cart that collides with the door is made harder. Due to such a change, the impact load applied to the side door panel in the side collision test by this Euro-NCAP in Europe becomes much larger than before.

  For such a side impact test by Euro-NCAP in Europe, even a side door made of an aluminum alloy inner panel as proposed in Patent Documents 2 and 3, depending on the conditions, There is a possibility that the deformation of the door lower structure entering the vehicle compartment cannot be suppressed. For this reason, even in automobile side doors made of an aluminum alloy inner panel, the side door (lower structure of the automobile side door) will not be greatly deformed and enter into the vehicle compartment at the time of side collisions where the conditions are severe. It is required to have excellent properties.

  However, even if the lower structure of the automobile side door made of an aluminum alloy inner panel is excellent in such side collision safety, the weight increases due to the use of many reinforcing members such as the door waist reinforcement, In addition, if the number of parts increases and the assembly and production become complicated, there is no point in practicality.

  Accordingly, the present invention is intended to provide a lower structure of an automobile side door that is excellent in collision safety against side collision, and is lightweight and easy to assemble even if a reinforcing member such as the door waist reinforcement is omitted. .

In order to achieve this object, the gist of the lower structure of an automobile side door excellent in collision safety according to the present invention is that an automobile side side in which an inner panel that constitutes a passenger compartment side is disposed with respect to an outer panel that constitutes a side face of a vehicle body. A lower structure of the door, wherein the inner panel is composed of a single aluminum alloy panel having a thickness of 1 to 4 mm, and the upper portion of the inner panel is replaced with a door waist reinforcement which is a reinforcing member. A rib formed from the inner panel itself is provided integrally, and this rib has an uneven cross-sectional shape extending in the vertical direction of the vehicle body, and extends in the longitudinal direction of the vehicle body of the inner panel, The bending strength of the upper part of the inner panel where the ribs are extended is determined in a cross section perpendicular to the vehicle body longitudinal direction of the upper part of the inner panel where the ribs are extended. As fully plastic moment against bending occurring in the side impact load is that it has a 300N · m or more.

  In order to achieve this object, another gist of the lower structure of an automobile side door excellent in collision safety according to the present invention is that an inner panel that constitutes a vehicle compartment side with respect to an outer panel that constitutes a vehicle body side face is provided. It is a lower structure of the arranged automobile side door, and the inner panel is composed of two aluminum alloy panels joined to each other with a thickness of 1 to 4 mm, and constitutes the upper side of the inner panel The aluminum alloy panel is made thicker than the aluminum alloy panel constituting the lower side, and the upper part of the aluminum alloy panel constituting the upper side of the inner panel is replaced with this inner member instead of the door waist reinforcement. A rib formed from the panel itself is provided integrally, and this rib has an uneven cross-sectional shape extending in the vertical direction of the vehicle body. In addition, the inner panel extends in the front-rear direction of the vehicle body of the inner panel, and the bending strength of the upper portion of the inner panel where the rib extends is determined by the vehicle body front and rear of the inner panel upper portion where the rib extends. The total plastic moment with respect to the bending caused by the side collision load in the cross section perpendicular to the direction is 300 N · m or more.

  The present invention can be applied to an automobile side door having a hybrid structure of a steel plate outer panel and an aluminum alloy inner panel, including an all aluminum side door in which both an outer panel and an inner panel are aluminum alloy panels.

  In the present invention, a rib formed from the inner panel itself is reinforced by replacing the door waist reinforcement which is a reinforcing member conventionally provided (without the door waist reinforcement) on the upper portion of the inner panel. In this case, reinforcement is performed so that the cross section of the rib is a certain level or more as a total plastic moment with respect to bending caused by a side collision load. In other words, ribs are integrally provided on the upper portion of the inner panel to reinforce such that a certain level of reinforcing effect is obtained.

  For this reason, even if a reinforcing member such as the door waist reinforcement is omitted, the present invention can secure the necessary rigidity and strength of the door that can cope with a side collision in which the above-mentioned standard is strict. In addition, it is light and can be easily formed and assembled without greatly increasing the weight.

  Embodiments of the present invention will be described below in detail with reference to the drawings. Hereinafter, the embodiment of the automobile side door lower structure of the present invention will be described with reference to FIGS. 1 and 3 are perspective views (after assembly) of the automobile side door of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 4 is a sectional view taken along line AA in FIG. 5 to 7 are cross-sectional views taken along line AA of either FIG. 1 or FIG.

Basic structure of automobile side door:
1 and 2, in an automobile side door lower structure 1a, an inner panel (inner plate) 2 constituting a vehicle compartment side is arranged with respect to an outer panel (outer plate) 3 constituting a vehicle body side surface. . The inner panel 2 and the outer panel 3 form a box-type hollow structure having an internal space 4. The thickness of the space 4 (thickness in the vehicle body width direction) ensures a door thickness corresponding to a side collision. Accordingly, even when a load (collision energy) due to a side collision from the side of the vehicle body (left side in the figure) indicated by the arrow direction in FIG. 2 is applied, the necessary rigidity as the lower structure 1a or 1b of the automobile side door is reduced. Necessary strength can be ensured. In each of cross-sectional views 4, 5, 6, and 7 to be described later other than FIG. 2, the load load direction due to the side collision is indicated by an arrow as in FIG.

Inner panel thickness:
The inner panel 2 of the automobile side door lower structure 1a, 1b is composed of an aluminum alloy panel having a thickness of 1 to 4 mm. If the thickness of the inner panel exceeds 4mm, the weight will increase and the advantage of weight reduction of aluminum alloy plate (panel) for the inner panel will be lost compared to the conventional thin steel plate material. The press formability of the aluminum alloy plate to the inner panel is also lowered. On the other hand, if the thickness of the inner panel is too thin, less than 1 mm, even if the rib in the present invention is provided on the upper portion of the inner panel, the height (depth) of the rib is increased or the number of ribs is increased. Even if it increases, the reinforcing effect does not appear. For this reason, the total plastic moment when the upper part of the inner panel provided with the rib is bent cannot be set to 300 N · m or more. Therefore, the thickness of the inner panel is set to a range of 1 to 4 mm.

  The inner panel 2 of the automobile side door lower structure 1a in FIG. 1 shows an embodiment composed of a single panel. In this case, the thickness of the inner panel 2 is usually the same regardless of the location due to the characteristics of the material aluminum alloy plate (rolled plate) used. However, since the thickness of the inner panel 2 on the right side that hits the door attachment portion (hinge portion) in FIG. 1 needs to be rigid to support the weight of the left inner panel 2 that is free when the door is opened, Even within the thickness range of 1 to 4 mm, it is necessary to increase the thickness accordingly. This also applies to the upper part of the inner panel where the rib 10 is extended. In order to obtain the reinforcing effect of the rib 10, it is necessary to increase the thickness within the above-described thickness range of 1 to 4 mm.

  Therefore, the thickness of the inner panel 2 is determined from the above-described rib reinforcing effect and the required rigidity on the door mounting portion side. For this reason, when a plate having the same thickness is used regardless of its location, such as the above-described rolled plate, the thickness of the inner panel 2 on the left side that becomes free when the door is opened tends to be excessive. For this reason, if possible, for example, a tailored blank material in which the thickness of the inner panel 2 on the right side corresponding to the door mounting portion in FIG. The differential thickness inner panel 2 may be used.

Differential thickness inner panel:
The inner panel of the automobile side door lower structure 1b in FIG. 3 is an example of such a differential thickness inner panel. That is, the inner panel of FIG. 3 is not a single aluminum alloy panel (single plate) as shown in FIG. 1, but an inner panel 2 and an inner panel 6 constituting the upper part of the inner panel in which the rib 10 is extended. In addition, a split structure is formed by joining two separate panels.

  The inner panel 6 that constitutes the upper part of the inner panel constitutes the upper part of the inner panel in which the ribs 10 are extended. The inner panel 6 has a 6a portion extending in the lateral direction and a door attachment portion (hinge portion) side in FIG. 3b, which extends in the vertical direction on the right side of FIG. This is because both the 6a portion and the 6b portion are inner panel portions that require strength and rigidity.

  That is, by making the inner panel into such a two-piece split structure, the upper side of the inner panel where the ribs 10 are extended, and the inner panel side (right side) corresponding to the door mounting portion (hinge portion) in FIG. Can be made relatively thick, selected from a thickness of 1 to 4 mm. Thereby, the strength and rigidity of these inner panel portions can be increased, and the reinforcing effect of the ribs 10 can be further increased.

  On the other hand, the thickness of the left inner panel 2 that is free when the door is opened, which does not require excessive thickening, can be selected from a thickness of 1 to 4 mm. Therefore, even if the thickness of the inner panel upper side where the ribs 10 are extended and the inner panel side corresponding to the door mounting portion is increased, an increase in the weight of the entire inner panel can be suppressed. For this reason, a difference thickness board (panel) like a tailored blank material is applicable. In this case, press molding of the inner panel main body 2 and press molding of the upper inner panel 6 itself and press molding for forming the rib 10 are performed simultaneously or continuously on the integrated tailored blank material. .

  If the inner panel has such a split structure of two sheets, the individual inner panels can be separately press-molded and then joined together to be integrated as an inner panel. Thereby, the press molding of the inner panel main body 2 which is a large panel and the press molding of the upper inner panel 6 itself and the press molding for forming the rib 10 can be performed separately, which is a difficult-to-form material than the steel plate. Facilitates press forming of aluminum alloy sheet to inner panel.

  No special means is required for joining the inner panel 2 and the inner panel 6 constituting the upper part of the inner panel with the ribs 10 extended, and no special means is required. The method can be used. For example, various welding methods such as spot welding, friction stir welding (FSW) welding, arcing, and laser can be applied in consideration of joining conditions, joining strength, workability, and the like. Further, mechanical joining such as SPR (self-piercing rivet), bolt coupling (a normal bolt, nut system or stud bolt system), mechanical clinching or the like can be applied. Furthermore, adhesion by an adhesive can also be applied. These joining means may be applied alone or in various combinations.

Reinforcement of automobile side door substructure (rib design conditions):
Characteristically, according to the present invention, ribs 10 formed from the inner panel itself are integrally provided and reinforced as shown in FIGS. The rib 10 has an uneven cross-sectional shape extending in the vertical direction of the vehicle body, and extends in the longitudinal direction of the vehicle body of the inner panel. And, in the present invention, this rib 10 is used instead of the door waist reinforcement, which is a reinforcing member, which is always provided in the upper portion (door waist reinforcement portion) of the inner panel 2 conventionally (door waist reinforcement). Is provided).

  When the material aluminum alloy plate is press-formed on the inner panel 2, the rib 10 is formed by simultaneously pressing the material aluminum alloy plate portion corresponding to the upper portion of the inner panel 2, thereby forming the upper portion of the inner panel 2 (door waist). Reinforcement part) is formed integrally with itself. This is the same even when the plate has a uniform thickness as in the case of the inner panel 2 formed of a single panel as shown in FIG. 1 or a differential thickness plate such as a tailored blank material. Further, in the form of the divided inner panels 2 and 6 as shown in FIG. 3, each material aluminum alloy plate having a different thickness is press-formed into the shape of the inner panels 2 and 6, and is formed on the upper portion of the inner panel 6 itself. The rib 10 is formed integrally.

  As shown in FIGS. 1 and 2, the cross-sectional shape of the rib 10 in the vertical direction of the vehicle body (vertical direction in the figure) is a ridge-like ridges 11 and 12 that are convex toward the side of the vehicle and a ridge that is concave toward the side of the vehicle. The recesses 13 and 14 have an uneven cross-sectional shape that is alternately and substantially parallel. Therefore, the ribs referred to in the present invention mean that the ribs and ridges extending in the longitudinal direction of the inner panel of the inner panel are alternately and substantially parallel in the vertical direction of the vehicle body. Say the uneven parts. Here, the shape of the concavo-convex cross section itself does not matter whether it is a rectangular concavo-convex shape as shown in FIGS.

  The ridges 11 and 12 and the ridges 13 and 14 in the rib 10 may have the same height (depth) h and width w in the vertical direction of the vehicle body, or may be different from each other. However, the height (depth) h and width w are preferably as high (deep) to large as the reinforcing effect increases. This reinforcing effect is naturally related to other elements and conditions, but in order to increase the reinforcing effect due to the height (depth) h and satisfy the strength of the upper portion of the inner panel described later, the concavo-convex cross-sectional shape of the rib 10 is used. It is preferable that the height h of the individual irregularities of the ridges 11 and 12 and the ridges 13 and 14 is 18 mm or more, and the width w of the irregularities is 15 mm or more.

  Further, the greater the number of the ridges 11 and 12 and the ridges 13 and 14 of the rib 10, the more preferable the reinforcing effect. For this reason, it is preferable that there are at least one or more combinations of one row of ridges and one row of ridges. For example, in the case of FIGS. 1 and 3, the ribs 10 are the protruding strips 11 and 12 and the concave strips 13 and 14, and the combination of the convex row 1 row and the concave row 1 row is two rows. However, the upper limit of the number of protrusions and recesses of the rib 10 is determined depending on whether or not the rib 10 can be molded.

  Further, if the strength of the inner panel upper part to be described later can be satisfied, the ridges 11 and 12 and the ridges 13 and 14 in these ribs 10 do not necessarily have to be provided parallel to each other or horizontally to each other in the longitudinal direction of the vehicle body. It may be tilted. Further, the ridges 11 and 12 and the ridges 13 and 14 in these ribs 10 are not necessarily linear or continuous, but may be curved or intermittent. That is, the rib 10 does not necessarily extend continuously in the front-rear direction of the vehicle body of the inner panel, or does not necessarily extend over the entire region of the inner panel of the vehicle body in the front-rear direction. Moreover, you may provide intermittently so that the part with and without the rib 10 may be formed over the front-back direction of the vehicle body of an inner panel.

  However, in order to increase the reinforcing effect of the convex strips 11 and 12 and the concave strips 13 and 14 in these ribs 10, it is necessary to extend the ribs 10 in the front-rear direction of the vehicle body of the inner panel. The length l of the inner panel of the ribs 11 and 12 and the concave stripes 13 and 14 in the rib 10 extending in the longitudinal direction of the vehicle body greatly contributes to the reinforcing effect, and if l is too short, the reinforcing effect is increased. Therefore, a length l approximate to this length is required corresponding to the length of the inner panel upper reinforcement position (waist reinforcement portion) extending in the front-rear direction of the vehicle body.

  The upper position of the inner panel 2 where the rib 10 is provided may be the same as the upper reinforcing position (waist reinforcement portion) of the inner panel where the reinforcing effect is maximized as the position where the conventional door waist reinforcement 103 of FIG. 9 described above is provided. . These ribs 10 are provided on the inner panel 2 by press molding of the inner panel 2 itself.

  Here, the rib 10 is separately manufactured as a reinforcing member separate from the inner panel 2, and is joined and integrated with the upper reinforcing position of the inner panel 2 as in the conventional door waist reinforcement 103 of FIG. In this case, as described above, the management cost and the joining cost increase due to the increase in the number of parts of the lower structure of the automobile side door. Also, in the case of a side collision, depending on the magnitude of the collision energy, these joints may be damaged, and the lower structure of the side door of the automobile will be greatly deformed and enter the passenger compartment, impairing the safety of passengers in the passenger compartment. Decreases.

  5 to 7 are modifications of FIGS. FIG. 5 shows a case where the molded panel 7 is attached to the attachment portion of the rib 10 at the upper part of the inner panel 2 from the upper outer side of the inner panel 2, and the space formed by the concave stripes 13, 14, 15 is reinforced as a closed space. . In FIG. 6, the molded panel 8 is attached to the attachment portion of the rib 10 at the upper part of the inner panel 2 from the upper inner side of the inner panel 2, and the space formed by the ridges 11 and 12 is reinforced as a closed space. FIG. 7 shows a further modification of the embodiment shown in FIG. 5 in which foamed resin is filled into each closed space formed by the concave stripes 13, 14, and 15 and is reinforced.

  Note that these molded panels 7 and 8 are not the conventional door waist reinforcement 103 of FIG. 9 described above, but are only panels that serve as a lid for forming the closed space. Moreover, these molded panels 7 and 8 are not the conventional steel door waist reinforcement 103 but, like the inner panel 2, are merely thin molded panels made of an aluminum alloy plate. The joining of the molded panels 7 and 8 may be the same as the joining means for the inner panel 2 and the inner panel 6 described above.

Inner panel top strength:
In the present invention, the strength and rigidity of the upper portion of the inner panel 2 where the rib 10 is extended = the waist reinforcement portion are remarkably improved by the reinforcing effect according to the design conditions and embodiments of the rib 10 described above. Specifically, at the portion where the rib 10 is extended, the cross section of the rib 10 is reinforced so that the total plastic moment with respect to the bending caused by the side collision load is 300 N · m or more. This total plastic moment is a total plastic moment with respect to the out-of-plane bending of the inner panel 2 in the vertical cross section of the rib 10, and against the bending caused by the side collision load in the cross section of the rib 10 perpendicular to the longitudinal direction of the vehicle body. The total plastic moment.

  This total plastic moment indicates the magnitude of the bending strength of the upper part of the inner panel 2 when a collision energy is applied to the upper part of the inner panel 2 during a side collision, and the strength of the upper part of the inner panel 2 against a side collision. It is an optimal scale when measuring This total plastic moment amount is widely used as an index for designing the bending strength of a member subjected to a bending load such as a beam in fields such as civil engineering and architecture, for example, “Structural Mechanics Formulas Collection”. However, in the present invention, this total plastic moment amount is not used as an index of the bending strength of the entire member (in the present invention field, the entire door) used in the civil engineering and construction fields. That is, the present invention is different from the conventional one in that the total plastic moment amount is limited to the upper part of the door inner panel provided with the rib 10 which is a part of the door structure.

  The stress state in the thickness direction when the upper part of the inner panel is deformed by a side collision load indicates a fully plastic bending state. Therefore, the bending moment at this time, that is, the total plastic moment Mp (N · m), can be theoretically obtained by an expression described later if the stress distribution is uniform in the width direction. If the total plastic moment is less than 300 N · m, the strength and rigidity of the upper portion of the inner panel 2 are insufficient, which is smaller than the reinforcing effect of the conventional door waist reinforcement 103 in FIG. 9 described above, and the significance of adopting the present invention. Is damaged. That is, when the door waist reinforcement is eliminated, it is impossible to suppress the deformation such that the side door (the lower structure of the automobile side door) enters the vehicle compartment at the time of a side collision.

This total plastic moment is the total plastic moment with respect to the bending due to the side collision load in the cross section of the portion where the rib 10 is extended on the upper part of the door inner panel 2 after press molding and before assembling to the door. Obtained from calculation of cross section. Specifically, as a cross-section of the rib 10, a range is assumed in which the starting point is wmm above the upper end of the concave strip 13 in the rib 10 and the lower end is wmm from the lower end of the convex strip 12 in the rib 10. Then, the total plastic moment around the neutral axis of the cross section with respect to the bending due to the side collision load of the cross section is obtained by calculation. Here, w is the width of the groove 13 or the protrusion 12. That is, as a state of full plastic bending, the bending stress at all locations is equal to the material yield strength σ _y outside the neutral axis of the cross section, and the bending stress at all locations of the material is −σ _y inside the neutral axis. In this state, the moment M _p calculated by the following equation based on the bending stress σ and the distance z from the neutral axis is defined as the total plastic moment.

上記式において、Ｍ_ｐは全塑性モーメント、Ａはリブ断面全体の断面積、σは曲げ応力、ｚは中立軸からの距離を意味する。

In the above equation, M _p is the total plastic moment, A is the cross-sectional area of the entire rib cross section, σ is the bending stress, and z is the distance from the neutral axis.

Other reinforcements:
In the present invention, the embodiment described above is further allowed to be provided with a reinforcement for ensuring collision safety. However, in the present invention, the rib 10 is provided instead of the conventional door outer waist reinforcement 103 provided on the upper portion of the door inner panel, and a reinforcing member such as the conventional door waist reinforcement 103 is not necessary. In the present invention, as described above, the strength and rigidity necessary for the door inner panel can be secured. Therefore, except for the reinforcement for ensuring collision safety, the reinforcement for increasing the overall rigidity and strength of the door inner panel itself is unnecessary. However, reinforcement installation that is attached to reinforce door components such as hinges for opening and closing the door is allowed as necessary.

  As described above, in the present invention, instead of the conventionally provided door waist reinforcement (without the door waist reinforcement), the inner panel itself is molded to reinforce the upper portion of the inner panel. To do. For this reason, the number of parts such as door waist reinforcement is reduced, and there are relatively few joints such as welding and self-piercing rivets associated with the installation of such a reinforcing material. Moreover, even if there is no door waist reinforcement, it is possible to prevent breakage from such a joint at the time of a side collision, and to prevent deformation of the side door entering in the direction of the passenger compartment. In addition, the labor for joining is reduced. Moreover, the weight increase accompanying installation of a reinforcing material can also be suppressed and the advantage of weight reduction using aluminum alloy is not impaired.

Material aluminum alloy plate:
The material aluminum alloy plate constituting the inner panels 2 and 6 or the molded panels 7 and 8 has a 0.2% proof stress when used as a vehicle body in order to ensure the strength and rigidity required as a door inner panel. A high strength of 180 MPa or more is preferable. The same applies to reinforcing materials such as the outer panel 3 and the door beam 104. As the material aluminum alloy plate, a general-purpose aluminum alloy plate of 5000 series, 6000 series, 7000 series, etc., which is generally used for this kind of structural member production (prepared after hot rolling and cold rolling) is appropriately selected. The

Other car side door lower structure:
In the present invention, other automobile side door lower structures are the same as those known. For example, in FIGS. 1 and 3, the internal space 4 also serves as a space for accommodating a window regulator that is a door glass lifting mechanism, a door mirror driving motor, a door latch mechanism, and the like in an integrally set state. The space 5 selectively provided at the center of the inner panel 2 serves as a work space for reducing the weight of the inner panel and accommodating the window regulator, the door mirror driving motor, the door latch mechanism, and the like.

  Although not shown in the figure, the frame constituting the window portion of the upper portion of the door is integrally joined to the upper portion of the door lower structure by welding or mechanical joining with the upper end portion 2a of the inner panel 2 or the like. It becomes. For this reason, the space formed by the upper end 2a of the inner panel 2 and the upper end 3a of the outer panel 3 is a space opened toward the upper part. The frame that forms the window at the top of the door may be made of a steel plate, or made of aluminum alloy (to form an aluminum alloy tube or hollow shape by hydroforming, It may be a molded alloy plate).

  As the outer panel 3, a normal panel having a thickness of 1.2 mm or less can be used, and a panel obtained by press-molding a steel plate may be used. A panel made of a formed aluminum alloy plate may be used.

  The lower end portion 2b of the inner panel 2 is sandwiched by the lower end portion 3b of the outer panel 3 that has been hemmed (folded by 180 degrees), and is integrated by a known method such as bonding, welding, or mechanical joining. .

  Moreover, although not shown in figure, the right end part of the inner panel 2 of FIG. 1 (inner panel 6 of FIG. 3) has a flange part for attaching the hinge used for attachment of a door, respectively.

Door beam:
2, 4 and 5 to 7 of the present invention, the door beam 104 for reinforcing the lower side of the lower structure of the automobile side door is the same as the conventional door beam of FIG. In other words, the vehicle absorbs energy for protecting passengers in the vehicle by receiving a load caused by a side collision of the vehicle body indicated by an arrow. For this purpose, the door beam 104 protrudes and extends from the side of the vehicle body, and it is necessary to receive a side collision load earlier. For this purpose, the door beam 104 is provided so as to protrude from the side of the outer panel 3 to the side of the vehicle body by a mounting bracket (flange) (not shown). The door beam 104 may be made of steel, but is preferably made of an aluminum alloy for reducing the door weight. In this respect, if the door beam 104 is an aluminum alloy extruded hollow member having a substantially rectangular cross section, it is preferable from the viewpoint of high energy absorption capability at the time of the side collision.

  Examples of the present invention will be described below. The undercarriage of the automobile side door shown in FIGS. 1 and 2 is actually manufactured by changing the conditions of the rib 10 at the upper part of the inner panel 2, and the strength test is performed on the door alone (the automobile side door lower structure alone). It was. These results are shown in Table 1.

The area of the lower part of the side door was about 0.84 m ² , the maximum width was about 160 mm, the length of the vehicle body in the longitudinal direction of the lower part of the door inner panel was 1200 mm, and the length of the vehicle body in the vertical direction was 700 mm. The door outer panel 3 uses a 6000 series aluminum alloy plate 1.2 mm thick material (0.2% proof stress 200 MPa), and the door inner panel 2 uses the same 6000 series aluminum alloy plate (0.2% proof stress 135 MPa). As shown in FIG. 1, the thickness of the door inner panel 2 was variously changed.

  The rib 10 is formed on the waist reinforcement portion, which is an upper position of the door inner panel 2, at the time of press forming of a 6000 series aluminum alloy plate on the door inner panel 2, and is formed at the position below the upper end of the panel by a width wmm below the width wmm. Molded at the same time so that the upper end position of the The conditions of the rib 10 formed thereby changed the height h, the length l, the width w, and the number (row) of the ridges 11 and 12 that are convex with respect to the side collision direction (vehicle body side direction). Incidentally, in the lower structure of the automobile side door shown in FIGS. 1 and 2, the number of the ridges 11 and 12 is two rows. The height h, the length l, and the width w of the ridges for each example were all the same.

  The door beam 104 has a hollow rectangular cross section having a cross-sectional width (vehicle body vertical direction) of 40 mm, a height (vehicle body width direction) of 38 mm, and a plate thickness of 2 to 4 mm, and a 1100 mm long 7000 series aluminum alloy extruded material (0.2 % Proof stress 400 MPa), and bolted to a position 100 mm from the lower part of the door outer panel 3 using a bracket made of 7000 series aluminum alloy extruded material, and installed horizontally.

(Total plastic moment)
The total plastic moment of the door inner panel 2 is against the bending due to the side impact load in the cross section of the portion where the rib 10 on the upper part of the door inner panel 2 is extended after press molding and before assembling to the door. The total plastic moment was obtained from the calculation of the cross section by the above formula.

(Door strength test)
The strength test method for the door was based on the “Test method for side door strength for passenger cars” issued by the Japan Society for Automotive Engineers. The outline of this test method is sufficiently high when a pressing tool (diameter 305 mm), which is a cylindrical jig, is pressed against a door in which the front and rear are fixed and a predetermined stroke (pushing amount: usually 300 mm at maximum) is applied. It is evaluated whether or not it has a deformation load. In the present invention, the deformation load of the door with an indentation amount of 250 mm was used as an evaluation item, and the load (kN) with an indenter indentation amount of 250 mm measured by this test was investigated. The larger the load, the less likely to be deformed in the direction of the vehicle interior due to a side collision, resulting in higher collision safety.

  A plurality of commercially available automobile side doors, including steel plates and aluminum alloys, were evaluated by the above-mentioned “Side Door Strength Test Method for Passenger Cars”. With the lowest strength, the load at an indenter pushing amount of 250 mm was 40 kN Met. Therefore, the test results were organized based on this value. The test results are shown in Table 1.

  According to Invention Examples 1 to 3, the total plastic moment of the upper portion of the door inner panel 2 (waist reinforcement portion) is 300 N · m or more. As a result, the inventive example eliminates the door waist reinforcement 103, reduces the number of parts, and obtains the door strength equivalent to the target commercial door.

  On the other hand, in Comparative Examples 1 to 4, it is inappropriate to provide the ribs (the height h, the length l, the width w, or the number of the convex ridges 11 and 12 is insufficient), or the inner The panel thickness is insufficient, and the total plastic moment of the upper part of the door inner panel 2 (waist reinforcement) is as low as less than 300 N · m. As a result, in Comparative Examples 1 to 4, when the door waist reinforcement 103 is eliminated, the target commercially available door strength is not reached.

  From the above, the effectiveness of the lower structure of the automobile side door according to the present invention and the critical significance of each requirement can be confirmed.

  ADVANTAGE OF THE INVENTION According to this invention, even if reinforcement members, such as the said door waist reinforcement, are abbreviate | omitted, the lower structure of the motor vehicle side door which is excellent in the collision safety with respect to a side collision, and is lightweight and easy to assemble can be provided. Therefore, the present invention can be applied to an automobile side door panel in which an outer panel is made of an aluminum alloy, including an all-aluminum door, and an automobile side door inner panel in which the outer panel is made of a steel plate.

It is a perspective view which shows the aspect of the lower structure of this invention automobile side door. It is sectional drawing of FIG. It is a perspective view which shows another aspect of the lower structure of the motor vehicle side door of this invention. FIG. 4 is a cross-sectional view of FIG. 3. It is sectional drawing which shows another aspect of the lower structure of the motor vehicle side door of this invention. It is sectional drawing which shows another aspect of the lower structure of the motor vehicle side door of this invention. It is sectional drawing which shows another aspect of the lower structure of the motor vehicle side door of this invention. It is a perspective view which shows the aspect of the lower structure of the conventional motor vehicle side door. It is sectional drawing of FIG.

Explanation of symbols

1: car side door lower structure, 2, 6: inner panel, 3: outer panel, 4, 5: space, 7, 8: panel, 10: rib, 11, 12: ridge, 13, 14, 15: concave Article 104: Door beam,

Claims (2)

  A lower structure of an automobile side door in which an inner panel constituting a vehicle compartment side is arranged with respect to an outer panel constituting a vehicle body side, wherein the inner panel is formed from a single aluminum alloy panel having a thickness of 1 to 4 mm. In the upper part of this inner panel, instead of the door waist reinforcement which is a reinforcing member, a rib molded from this inner panel itself is integrally provided, and this rib is an uneven cross section extending in the vertical direction of the vehicle body The inner panel has a shape and extends in the front-rear direction of the vehicle body of the inner panel, and the bending strength of the upper part of the inner panel from which the ribs are extended is the upper part of the inner panel from which the ribs are extended. In the cross section perpendicular to the longitudinal direction of the vehicle body, the total plastic moment with respect to the bending caused by the side collision load is set to 300 N · m or more. Lower structure of the automobile side door to.   A lower structure of an automobile side door in which an inner panel constituting a vehicle compartment side is arranged with respect to an outer panel constituting a vehicle body side, wherein the inner panel is joined to each other with a thickness of 1 to 4 mm. The aluminum alloy panel is composed of a single aluminum alloy panel, and the aluminum alloy panel constituting the upper side of the inner panel is made thicker than the aluminum alloy panel constituting the lower side, and further the aluminum alloy constituting the upper side of the inner panel. In the upper part of the panel, instead of the door waist reinforcement which is a reinforcing member, a rib formed from this inner panel itself is integrally provided, and this rib has an uneven cross-sectional shape extending in the vertical direction of the vehicle body, The inner panel extends in the front-rear direction of the vehicle body of the inner panel, and extends the rib. The bending strength of the upper part of the steel plate is 300 N · m or more as a total plastic moment against bending caused by a side collision load in the cross section perpendicular to the longitudinal direction of the vehicle body of the upper part of the inner panel where the ribs are extended. The lower structure of the automobile side door.

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