JP2002029337A - Member for reinforcing bumper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy bumper reinforcing member capable of changing easily and freely a cross-sectional area and cross-sectional height of the reinforcing member in respone to design conditions of various car models and bodies, and easily manufactured and attached. SOLUTION: Fellow hollow sections 2a, 2a made of aluminum alloy of a substantially rectangular cross section are arrayed in parallel along the vehicle width direction, and the arrayed fellow hollow shape materials 2a, 2a are connected each other to be integrated as the single bumper reinforcing member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Detailed description of the invention]

[0002]

2. Description of the Related Art Inside a bumper attached to a front end (front) and a rear end (rear) of a vehicle body such as an automobile, a bumper reinforcing material (also referred to as a bumper reinforcement or a bumper reinforcement) as a strength reinforcing member is provided. ) Is provided.

As is well known, the bumper reinforcing member is disposed between the bumper and the vehicle body so as to extend substantially horizontally with respect to the vehicle body and parallel to the vehicle width direction. The bumper reinforcing material is attached to the vehicle body by connecting the vehicle body such as a front side member or a rear side member directly or directly to the front or rear end of the body frame (body members) of the frame member in the vehicle front-rear direction. It is connected and fixed via a member for use.

More specifically, as disclosed in, for example, Japanese Patent Application Laid-Open No. 4-31152, a front side member extending in the longitudinal direction of the vehicle body is provided with a hollow structure such as a bumper stay. This is a structure in which a bumper reinforcing member having a hollow structure having a substantially rectangular cross section is fixedly extended in the vehicle width direction and substantially in the horizontal direction. With such a structure, in the event of a collision from the front of the vehicle body, the bumper reinforcing material is crushed in the lateral direction and the bumper stay is crushed in the axial direction to absorb the collision energy.

[0005] Therefore, the connection structure between the bumper reinforcing member as the vehicle body energy absorbing member and the bumper stay as the vehicle body connecting member receives the external force energy (collision energy) applied by the vehicle body collision. The ability to absorb the plastic deformation (buckling deformation) and protect the vehicle body members and the like is required.

In recent years, these bumper reinforcements have been replaced with 5000 series, instead of steels conventionally used for weight reduction.
Extruded sections made of high-strength Al alloys such as 6000 series and 7000 series and having a rectangular cross section have begun to be used.

The cross-sectional shape of the extruded profile for the bumper reinforcing member is preferably a mouth-shaped hollow structure from the viewpoint of weight reduction. However, as is well known, the cross-sectional area, cross-sectional height, required strength, and the like of the bumper reinforcing member differ depending on the vehicle type and the design conditions of the vehicle body. For this reason, in the case of a bumper reinforcing member having a large cross-sectional area or cross-sectional height, in order to secure necessary bending strength and crushing characteristics, a hollow middle structure is provided with a reinforcing middle rib. Tagata and eye shapes are also used.

According to the extruded aluminum alloy material,
It is possible to efficiently and mass-produce shaped members having the same cross-sectional shape in the longitudinal direction, such as the cross-sectional shape of the mouth, or the cross-sectional shape of the sun, the rice, or the eye.

However, as the application of the extruded aluminum alloy material to the bumper reinforcing member expands, the number of applicable vehicles and the number of design conditions of the vehicle body also increase dramatically. As described above, the cross-sectional area, cross-sectional height (position or height in the vehicle height direction), or required strength of the bumper reinforcing member differs depending on the vehicle type and the design conditions of the vehicle body.

[0010] In recent years, further improvement in the collision safety of the vehicle body has been demanded, and the collision safety standards of the vehicle body, such as an offset collision test, have become increasingly strict. Accordingly, in response to this, the design conditions of the bumper and the bumper reinforcing member have been greatly changed for each vehicle type, such as the sectional area and the sectional height of the bumper and the bumper reinforcing member of the vehicle body have been increased or the installation position has been increased. Tend to be.

[0011]

In this regard, in the conventional bumper reinforcing member made of a single member, the restriction due to the increase in weight (thickness and reinforcing rib) for improving the bending strength and the shape of the cross-sectional shape that can be manufactured are not considered. There are restrictions. For this reason, the cross-sectional area or the cross-sectional height of the bumper reinforcing member cannot be freely changed according to the design conditions.

[0012] In the conventional bumper reinforcing member made of a single member, the manufacturing side of the bumper reinforcing member or the extruded shape member made of Al alloy requires the various vehicle types and design conditions of the vehicle body, or the cutting of the bumper reinforcing member. It is necessary to make or prepare various bumper reinforcing members and extruded members corresponding to the change of the area or the sectional height. And such diversification requires productivity and low cost for manufacturing side of bumper reinforcing members and extruded profiles, such as requiring many dies, processes and process conditions for extrusion process and molding process. This leads to significant inhibition of conversion.

Further, when the cross-sectional area or the cross-sectional height of the bumper reinforcing member is changed, the characteristics such as the bending strength, the crushing strength, and the amount of collision energy absorption naturally change. Therefore, for each design change of the cross-sectional shape of the bumper reinforcing member, whether or not the required characteristics are satisfied is analyzed, and
It is necessary to verify by conducting a bending test or crush test using a prototype. Therefore, the time required for the analysis and / or the bending test and the crush test due to the change in the sectional shape design of the bumper reinforcing member becomes enormous.

Further, when the cross-sectional shape of the bumper reinforcing member is changed in design, the way of attaching the bumper reinforcing member to the side member naturally becomes different. Therefore, it is necessary to change the design including the structure and shape of the bumper stay. If the mounting method to the side member is different, the bending strength and the crushing characteristics of the bumper reinforcing member structure naturally change. For this reason, the analysis and / or the crush test are further required for the bending strength and the crush characteristics as the bumper reinforcing member structure including the bumper stay, and the time and labor required for the analysis are further increased.

In summary, in the conventional bumper reinforcing member made of a single member, the sectional area or the sectional height of the bumper reinforcing member cannot be freely changed. In addition, various bumper reinforcing members and extruded members must be separately prepared. And a great deal of effort has been paid for predicting and evaluating characteristics in response to the various bumper reinforcing members one after another. Further, on the manufacturing side of the bumper reinforcing member, a great deal of effort has been paid to increase the production and lower the cost of the extrusion process and the molding process in response to frequent design changes.

Therefore, an object of the present invention is to easily and freely change the cross-sectional area or the cross-sectional height of the bumper reinforcing member in accordance with the various vehicle types and the design conditions of the vehicle body, and to provide a flexural strength. It is an object of the present invention to provide an Al alloy bumper reinforcing material that is easy to analyze and evaluate, and that is easy to manufacture and install.

[0017]

Means for Solving the Problems To achieve this object, the gist of the present invention is to arrange aluminum alloy hollow profiles having a substantially rectangular cross section in parallel to the vehicle width direction and to form an array. That is, the hollow members thus formed are connected to each other and integrated as a single bumper reinforcing member.

[0018] The bumper reinforcing material of claim 1 is originally used as a bumper reinforcing material, and its bending strength and crushing characteristics are known, and its manufacturing process and mounting method have been established.
It is premised that hollow sections made of an Al alloy having a substantially rectangular cross section and simple in shape are arranged in the vehicle width direction and used in combination according to the design change of the bumper reinforcing member.

Therefore, the aluminum alloy hollow members arranged in parallel with or in the vehicle width direction at an interval or without an interval are connected to each other and integrated as a single bumper reinforcing member. Thereby, the cross-sectional area or the cross-sectional height of the bumper reinforcing member can be easily and freely changed according to the various vehicle types and the design conditions of the vehicle body.

Further, since the bending strength and the crushing characteristics of the individual hollow members are known and the hollow members having the known bending strength and crushing characteristics are used, the characteristics of the integrated bumper reinforcing material can be easily evaluated. is there. In addition, it is possible to easily manufacture individual hollow members, integrate a single bumper reinforcing material, or attach an integrated bumper reinforcing material.

Further, according to the present invention, as in the gist of claim 2 of the present invention, as an aluminum alloy hollow profile to be used, a mouth shape, a Japanese shape, an eye shape, which is originally used as a bumper reinforcing material.
It can be freely selected from hollow profiles with a cross section of the shape of a triangle.

For this reason, it is very easy to secure necessary bending strength and crushing characteristics in accordance with a design change of the bumper reinforcing member, such as increasing the sectional area and the sectional height of the bumper reinforcing member. Further, there is a great deal of room for selecting a design change of the bumper reinforcing member, such as the size and weight, the bending strength, and the crushing characteristics.

Further, as in the gist of the third aspect of the present invention, it is more preferable to connect the hollow members combined in parallel in the vehicle width direction by a bumper stay.

By connecting the hollow members with a bumper stay, a new member for connection is not required, or even if necessary, it can be minimized. For this reason, the number of attachment steps by a new connecting member does not increase, or even if it increases, it can be minimized. Further, there is no weight increase due to the new connecting member, or even if the weight increases, it can be minimized.

Further, Al used for the bumper reinforcing member of the present invention
The alloy is AA to JIS 50 as in the gist of claim 4 of the present invention.
It is preferable to select from the 00 system, the 6000 system, and the 7000 system.
These Al alloys are suitable for use in the bumper reinforcing member of the present invention and a bumper stay for mounting, since they are excellent in moldability and high in strength, and are easily manufactured by extrusion or the like.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a bumper reinforcing member according to the present invention will be described below with reference to the drawings. An embodiment of the bumper reinforcing member of the present invention is shown in a partially sectional perspective view of FIGS.

First, in FIG. 1, a bumper reinforcing member 1a of the present invention made of an extruded Al alloy is basically composed of two substantially rectangular Al alloy hollow profiles 2a, 2a having a mouth-shaped cross section. Are arranged vertically in the vehicle width direction in order to have a design height required for the bumper reinforcing member.

In this embodiment, an aluminum alloy hollow profile 2a,
2a is arranged in such a manner as to be arranged at intervals in the vertical direction. However, depending on the design height and width required for the bumper reinforcing member and the height and width of the aluminum alloy hollow profile on hand, and further, depending on the required crushing strength and the constraints of the mounting method, etc. Various arrangements and combinations of materials are selected.

More specifically, they may be arranged densely (without a gap) in the direction of the vehicle body or may be arranged with a gap between them.
Various combinations in the vehicle width direction, such as arranging closely parallel in the vertical direction or arranging with an interval, are selected.

The type and number of hollow sections to be combined are also shown in FIG. 3. As illustrated in FIG. 3, the cross section of the hollow sections schematically illustrates the combination of the hollow sections. Bumper reinforcement member 1c ~
1 g is appropriately selected.

In the bumper reinforcing members 1c to 1g shown in FIG.
Fig. 3 (a) shows the hollow hollow members 2d, and Fig. 3 (b) shows the hollow hollow members 2e.
, FIG.3 (c) is a hollow hollow section 2f, FIG.3 (d) is a hollow section 2a and a hollow section 2d, and FIG.3 (e) is a hollow section 2a.
It illustrates an example of how to combine them vertically and vertically, such as with the eye-shaped hollow shaped members 2e.

Incidentally, the bending strength and the crushing characteristics of the bumper reinforcing member can be determined by the conventional single-section rectangular hollow member or the divided structure as in the present invention.
As long as they are made of the same material and have the same cross-sectional area, there is not much difference. This is within the scope of the present invention, when assembling hollow profiles in parallel in the vehicle width direction, the same applies when the hollow profiles are closely arranged without spacing, and also when the hollow profiles are arranged at intervals. It is. As a result, the bumper reinforcing member of the type according to the present invention can be reinforced by a conventional single-section rectangular hollow profile having the same material and cross-sectional area (size and bulk) as long as the hollow profiles are securely connected to each other. Bending strength and crushing characteristics can be secured to be equal to or more than those of the member.

For this reason, even if the design of the bumper reinforcing member is changed due to the design change of the vehicle body, the required height, width, weight, required bending strength and crushing strength of the bumper reinforcing member, or the mounting Depending on the constraints and the like, the height, width, weight, or bending strength or crushing strength of each hand-held or known hollow profile can be considered, and the combination of the hollow profiles can be appropriately selected. Become.

In other words, as shown in FIG. 3, if only a typical hollow shape member and a typical combination example are prepared, it is possible to sufficiently cope with a design change of the bumper reinforcing member.
As a result, unlike the related art, there is no need for the manufacturing side of the bumper reinforcing member to separately produce or prepare various types of bumper reinforcing members in order to cope with various vehicle types and vehicle body design conditions. In addition, in order to manufacture a variety of extruded aluminum alloy profiles for bumper reinforcement members, many dies are not required for the extrusion and molding processes, which hinders productivity and cost reduction. There is no.

In the present invention, in order to further improve the bending strength and the crushing characteristics as a bumper reinforcing member for improving the collision safety, the hollow plate is not changed in design and the reinforcing plate or the reinforcing member is used. It is also permissible for the profiles to be provided at appropriate places in the combined hollow profile.

For example, in the case of the bumper reinforcing member shown in FIG. 1, a method of reinforcing the bumper reinforcing member which requires a large bending strength in order to improve collision safety will be described with reference to FIGS. 4 (a) and 4 (b). This will be described with reference to a front view of the bumper reinforcing member 1a. In FIG. 4 (a), a reinforcing plate 12 corresponding to the shape of the front surface is provided on the front side of the center of the aluminum alloy hollow profiles 2a, 2a. FIG. 4 (b) shows a reinforcing section 13 corresponding to the shape of the gap in the center of the hollow section of the Al alloy hollow section 2a.
Is provided. Another advantage of the present invention is that such reinforcement can be easily performed in response to a change in the design of the bumper reinforcing member.

Next, an embodiment of a method of connecting the arranged hollow members will be described with reference to FIG.

In FIG. 1, two aluminum alloy hollow sections 2a, 2a having a mouth-shaped cross section are connected to the backs (rear walls) 4a, 4b at both ends of the hollow sections 2a, 2a by stays 3a, 3a. Are connected and fixed to each other. In FIG. 1, the left side of the figure is the front direction of the vehicle body, and a bumper reinforcing material attached to the vehicle body front bumper is assumed.

The stays 3a, 3a are provided with front walls 5 corresponding to the back surfaces (rear walls) 4a, 4b at both ends of the hollow members 2a, 2a, and flanges projecting vertically from the front wall 5 (sideways). Part 8
a, 8b. The rear wall 6 has side walls 7a and 7b for supporting the front wall 5 from behind and a rear wall 6 connected to the side walls and parallel to the front wall 5, and has a hat-shaped hollow cross section as a whole.

It should be noted that the stay 3 having such a hollow cross-sectional shape is used.
The materials a and 3a are difficult to manufacture with iron,
There are also problems of electrolytic corrosion with the bumper reinforcing member made of an alloy and problems of a large specific gravity and a large weight increase.

The flanges 8a, 8b of the stays 3a, 3a are arranged in the vertical direction (side) of the stays 3a, 3a in order to facilitate the fixing of the stays 3a, 3a to the back surfaces 4a, 4b of the hollow sections 2a, 2a. ). That is, in the embodiment of FIG. 1, in the flange portions 8a, 8b, the stays 3a, 3a and the back surfaces 4a, 4b of the hollow members 2a, 2a are fastened by fastening means such as bolts 9a and 9b and 9c and 9d. Mechanically joined. At the time of this mechanical joining, the work is simplified by appropriately providing working openings on the rear side or the front side of the hollow sections 2a, 2a.

In addition, as shown in FIG. 1, if the side walls 7a and 7b of the stays 3a and 3a are tapered so that the distance between the side walls 7a and 7b decreases in the rearward direction of the vehicle body (rightward in FIG. 1). The mechanical joining is facilitated without interference or restriction by the main body.

In addition, the connection between the flange portion of the stay and the back surface of the hollow member can be easily performed by driving a self-piercing (self-piercing) rivet or the like from the front surface side of the flange portions 8a and 8b, for example. Can be mechanically connected and fixed.

Furthermore, the contact surfaces of the end portions of the flange portions 8a and 8b of the stay with the back surface of the hollow profile can be connected and fixed by welding. When the electrode is placed in the hollow structure of the hollow member, the electrode itself can be easily attached to the plate-shaped flange portion, so that joining by spot welding is also possible.

The stay is attached to the side member (not shown) by mechanically joining the front wall of the side member with the rear wall 6 of the stay 3a, 3a, or by attaching the rear wall 6 to the side member. This is performed by fitting into the hollow part of the member. Furthermore, on the front wall of the side member,
A bolt heading to the left (in the figure) may be appropriately embedded in advance, a hole corresponding to the bolt may be provided on the rear wall 6 side, and the hole may be inserted into the bolt and fixed.

FIG. 1 also discloses an embodiment in which the hollow members 2a are connected to each other using a connecting member in addition to the connection using the stay. That is, the hollow members 2a, 2a
In the vicinity of the center in the longitudinal direction, a flat plate-shaped connecting member 10 is attached to the back surfaces of the hollow profiles 2a, 2a, and mechanically joined by fastening means such as bolts 9e and 9f.

The auxiliary connecting member 10 is provided at an appropriate position as required, and a mechanical joining or a welding joining is appropriately selected as a fixing method. However, when used together with the connection by the stay, as described above, the number of attachment steps by the connection member does not increase, or even if it increases, to minimize it.
Also, it is provided so that the weight increase due to the new connecting member does not occur, or even if it increases, the weight can be minimized.

Next, another embodiment in which the cross-sectional shape of the hollow profile as the bumper reinforcing member is different will be described with reference to FIG.

In FIG. 2, two aluminum alloy hollow members 2b and 2c each having a mouth-shaped cross section have a rectangular cross section as in FIG. 1, but have one side in the vertical direction (side) on the rear wall side. It has flange portions 11a and 11b that protrude only on it. The rear surfaces (rear walls) 4c, 4d of both ends of the flange portions 11a, 11b
Are connected and fixed to each other by the same stays 3a as in FIG. 2, the left side of the figure is the front direction of the vehicle body.

FIG. 2 is different from FIG. 1 only in the cross-sectional shape of the hollow member to be combined.
The structure and mounting method of 3a are basically the same as those in FIG. The hollow members 2b and 2c have symmetrical shapes in which the extending directions of the flange portions 11a and 11b are different.

Further, another embodiment of the method of connecting the arranged hollow members will be described with reference to FIG.

FIGS. 5A to 5C are the same as those in FIG.
It is assumed that a bumper reinforcement is made of two aluminum alloy hollow sections 2a, 2a having a mouth-shaped cross section and attached to a vehicle front bumper (however, only the left half of the bumper reinforcement is shown). 5A to 5C, (a) is a perspective view of the bumper reinforcement, (b) is a plan view of the bumper reinforcement, (c)
FIG. 3 is a front view of a bumper reinforcing member.

In FIGS. 5 (a) to 5 (c), the hollow sections 2a are connected to each other at the back (rear wall) 4a at both ends of the hollow sections 2a, 2a as in the case of FIG. 14, they are connected and fixed to each other.

However, the shape of the stay 14 is different from that of FIG. 5 (a) to 5 (c) are a front wall 17 corresponding to the back surface 4a at both ends of the hollow profiles 2a, 2a, side walls 18a, 18b supporting the front wall 17 from behind, and the side walls. Flanges 16a, 16 projecting from side to side (sideways) from
It is characterized in that it has a hat shape, is entirely hat-shaped, and has an open cross-sectional shape that extends rearward. This stay 14
Can be easily produced by bending an Al alloy extruded shape or an Al alloy plate, a steel plate, or the like.

The flange portions 16a and 16b of the stay 14 facilitate attachment to the side member 15. That is, the through-holes 20a, 20b are formed in the flange portions 16a, 16b of the stay 14 and the flange portions 19a, 19b on the front surface of the side member 15.
20b, 20c, 20d are provided, and bolts 21c, 21c are provided in the through holes.
By passing through a fastening means such as d, mechanical and simple joining can be achieved.

The stay 14 and the back surface 4a of the hollow members 2a, 2a
The bolts 21a and 21b directed toward the front of the vehicle body (left side in the figure) are appropriately embedded in the front wall 17 of the stay 14 in advance, and holes (not shown) corresponding to the bolts 21a and 21b are hollowed. It is provided on the back surface 4a side of each of the profiles 2a, 2a, and the bolts 21a, 21b are inserted into these holes. At the time of this mechanical joining, if the working holes are appropriately provided on the front side of the hollow profiles 2a, 2a, etc., the work is simplified.

In addition, the contact surface between the front wall 17 of the stay 14 and the back surface of the hollow member can be fixed by welding. Therefore, the mounting method shown in FIG. 5 is simpler than the mounting method shown in FIG. 1 depending on the case and conditions.

(Applicable Al Alloy) Next, the Al alloy used in the bumper reinforcing material and the stay of the present invention will be described. The Al alloy itself used in the profile of the present invention is usually selected from AA to JIS 5000 series, 6000 series, 7000 series and other general-purpose (standard) Al alloys with relatively high proof stress commonly used for this kind of structural member use. Used. Among them, in particular, these 7000 series (Al-Zn-Mg series) Al
A tempering material such as T5 or T6 of an alloy or a 6000 series (Al-Mg-Si series) Al alloy is preferable in terms of strength, corrosion resistance, and workability.

However, on the other hand, even with a special Al alloy whose components and structures are variously proposed from the material side described above, by adopting the structure of the present invention, the strength and energy absorption performance are naturally increased. It will be excellent. Therefore, in terms of cost, conventional general-purpose (standard) Al alloy material is promising, but of course, even if it is a conventional special Al alloy,
It can be used in the present invention.

(Production of Al Alloy Shaped Material) The bumper reinforcing material or stay of the present invention is basically composed of an Al alloy extruded shape material. The production itself of this extruded profile is appropriately produced by a usual method including casting, homogenization heat treatment, hot extrusion, tempering heat treatment and the like as main steps. The use of such an extruded profile makes it possible to easily and efficiently produce a profile having a complicated cross section. However, the bumper reinforcing material is not necessarily an extruded shape material, but may be manufactured by forming an Al alloy plate and then welding. Also, the stay 14 may be manufactured by molding an Al alloy plate.

[0061]

According to the present invention, it is possible to easily and freely change the cross-sectional area or the cross-sectional height of the bumper reinforcing member in accordance with various vehicle types and design conditions of the vehicle body, and furthermore, the bending strength and the like. It is possible to provide an Al alloy bumper reinforcing material that is easy to analyze and evaluate the crushing characteristics, and that is easy to manufacture and install. For this reason, Al
This greatly expands the use of alloy materials, and has great industrial value.

[Brief description of the drawings]

FIG. 1 is a partially sectional perspective view showing one embodiment of a bumper reinforcing member according to the present invention.

FIG. 2 is a partially sectional perspective view showing another embodiment of the bumper reinforcing member according to the present invention.

FIG. 3 is a sectional view showing another embodiment of the bumper reinforcing member according to the present invention.

FIG. 4 is a front view showing another embodiment of the bumper reinforcing member according to the present invention.

FIG. 5 shows another embodiment of the bumper reinforcing member according to the present invention, wherein (a) is a perspective view, (b) is a plan view (partial cross section),
(c) is a front view.

[Explanation of symbols]

1: Bumper reinforcement, 2: Hollow profile, 3, 14: Bumper stay, 4: Rear wall back, 5, 17: Stay front wall, 6: Stay rear wall, 7, 18: Stay side wall, 8, 16: Stay flange, 9, 21: Fastener, 10: Reinforcement plate, 11: Flange, 1
2: Reinforcement plate, 13: Reinforced profile, 15: Side member, 19:
Side member flange, 20: Through hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Nimura 14-1, Chofu Minatomachi, Shimonoseki City, Yamaguchi Prefecture Inside Kobe Steel, Ltd. Chofu Works (72) Inventor Takashi Oka 141-1, Minatomachicho, Shimonoseki City, Yamaguchi Prefecture Shares (72) Inventor Harunobu Yamada 14-1, Chofu Minatomachi, Shimonoseki-shi, Yamaguchi

Claims (4)

[Claims] 1. An aluminum alloy hollow profile having a substantially rectangular cross section is arranged in parallel in the vehicle width direction, and the arranged hollow profiles are connected to each other to be integrated as a single bumper reinforcing material. A bumper reinforcing material characterized by that: 2. The bumper reinforcing material according to claim 1, wherein a cross-sectional shape of the hollow profile is selected from a mouth shape, a Japanese shape, an eye shape, and a rice shape. 3. The bumper reinforcement according to claim 2, wherein the hollow members are connected to each other by a bumper stay. 4. AA to JI as the aluminum alloy
The bumper reinforcing material according to any one of claims 1 to 3, wherein a standard aluminum alloy selected from S 5000 series, 6000 series, and 7000 series is used.