JPH06305445A - Locknut for undercarriage frame - Google Patents

Abstract

PURPOSE:To prevent the damage of a cross member and a reinforcing member effectively by forming a nut of a cast product provided with a base part with a threaded hole to be screwed with a bolt, and a bent part formed in the bent state at one end of the base part so as to come in contact with a plate part adjacent to the fitting flange of the cross member. CONSTITUTION:A nut 24 is formed of a base part 24a coming in contact with a fitting flange 20, a clamped member, and a bent part 24b formed in the bent state at one end part of the base part 24a. A disc-shaped protruding part 24c is formed at the base part 24a, and the protruding part 24c is provided with a threaded hole 24d bored so as to be screwed with the screw shank part of a bolt 14. Since the nut 24 is a cast product, the cross-sectional shape of a connection part 24c between the base part 24a and the bent part 24b can be easily formed into such optimum shape as to prevent stress concentration based on bending load or at least reducing the degree of stress concentration sufficiently compared to a conventional reinforcing member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastening nut for a chassis frame of a truck or the like.

[0002]

2. Description of the Related Art An example of the structure of a chassis frame of a truck or the like will be described with reference to FIGS. Reference numeral 10 in the figure
Indicates an undercarriage frame as a whole, and the undercarriage frame extends in the vehicle front-rear direction and has a pair of left and right side rails 12 each having a groove-shaped cross section, and extends in the vehicle width direction at both ends thereof with a bolt 14 and the same. It is composed of a cross member 18 fastened to the side rail 12 by a nut 16 screwed to a bolt.

The cross member 18 shown in the drawing has a groove-shaped cross-sectional shape consisting of upper and lower flanges 18f and a vertical web 18w that connects one side edge of the upper and lower flanges to each other. Both ends in the width direction are bent in the vertical direction to form the mounting flange 20. The mounting flange 20 is fastened to the web 12w of the side rail 12 by the bolt 14 and the nut 16 screwed to the bolt, and when the load acting on the fastening portion is large, it is well shown in FIG. As described above, an L-shaped reinforcing member 22 generally called a patch is interposed between the mounting flange 20 and the nut 16.

The reinforcing member 22 is the mounting flange 2
A plate-like base plate portion 22a which is in contact with the plate member 0 and a plate portion which is formed by bending at one end portion of the base plate portion and is adjacent to the mounting flange 20 of the cross member (in the illustrated case, the upper and lower flanges
8f) and a bent portion 22b that abuts on the plate 8f), and is conventionally formed by pressing a plate material.

In the above-mentioned conventional side rail and cross member fastening structure, when the acting load at the fastening portion of the bolt 14 is large, the reinforcing member 2 is provided along the outer peripheral edge of the nut 16.
A crack due to stress concentration is likely to occur in the second board portion 22a, and a bending load acts on the connecting portion between the board portion 22a and the bent portion 22b to easily break this portion. Has the disadvantage of being lost or reduced,
Furthermore, since the reinforcing member 22 and the tightening nut 16 are separate members, the number of parts is increased, the assembly work is troublesome, and the manufacturing cost is increased.

In the illustrated chassis frame 10, the upper and lower flanges 18f of the cross member 18 having the groove-shaped cross section are bent at both ends in the vertical direction to form the mounting flange 20, and the web 18w of the cross member 18 is formed. There is a case where both end portions of the are bent in the front-rear direction to form the mounting flange 20, and the mounting flange 20 is interposed by the reinforcing member 22 and fastened by the bolts 14 and the nuts 16. In this case, the same problem as described above is also caused. was there. Further, both ends of the upper and lower flanges 18f of the cross member 18 having an I-shaped cross section are bent in the vertical direction to form the mounting flange 20, or both ends of the web 18w are bent in the front-rear direction of the vehicle body for mounting. In the case where the flanges 20 are formed, the reinforcing members 22 are interposed on the mounting flanges 20 and the bolts 14 and the nuts 16 are used to fasten the webs 12w of the side rails, the same problem as described above occurs. Further, an upper member having a hat-shaped cross section in general, and a lower member arranged along the upper member along its entire length or only near both ends of the upper member and fixed to the upper member by rivets or the like. In a so-called alligator-type cross member in which a connecting portion expanded in a V shape by an upper member and a lower member is formed at both ends, end portions of the upper member and the lower member in the connecting portion are respectively arranged in a vertical direction. Bending 1 to form a mounting flange, and mounting a reinforcing member on the mounting flange, bolt 1
4 and the nut 16 are also fastened to the side rail web, there is a problem that the reinforcing member is easily damaged and the manufacturing cost is increased as in the above case.

[0007]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances. It has a small number of parts, the side rail and cross member can be easily fastened together, the manufacturing cost is low, and the stress concentration is based. An object of the present invention is to provide a fastening nut for a chassis frame that can effectively prevent damage to the cross member and the reinforcing member, and as a result can improve the durability and reliability of the chassis frame. .

[0008]

To achieve the above object, the present invention is directed to a pair of left and right side members extending in the vehicle front-rear direction such that both ends of a cross member extending in the vehicle width direction extend in the vehicle front-rear direction. In what is fastened to the rail with bolts,
The nut screwed with the bolt is formed by bending at one end of the substrate portion and the board portion having a screw hole into which the bolt is screwed and abutting on the mounting flange of the cross member. A fastening nut for an undercarriage frame is proposed, which is formed of a cast product including a bent portion that abuts a plate portion adjacent to the mounting flange of the cross member.

[0009]

According to the present invention, since the screw hole is directly formed in the base plate portion which is brought into contact with the mounting flange of the cross member, the nut also serves as a conventional reinforcing member, so that the number of parts is reduced, and Assembling the cross member and the side rail becomes easy. Further, since the nut consisting of the substrate portion and the bent portion is preferably composed of an integrally cast product of ductile cast iron, the shape of the connecting portion between the substrate portion and the bent portion, stress concentration does not substantially occur, Alternatively, it can be easily formed into a desired shape in which the stress concentration is at least significantly smaller than that of the conventional reinforcing member obtained by bending and pressing a plate material.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to an enlarged cross-sectional view of a main part of FIG.
(Note that members and portions substantially the same as those of the conventional configuration described with reference to FIGS. 3 and 4 are denoted by the same reference numerals, and duplicate description will be omitted.) According to the present invention, the bolt 14 In cooperation with the side rail 1, the mounting flange 20 is formed by bending the ends of the upper and lower flanges 18f (the upper flange is illustrated in FIG. 1) of the cross member 18 in the vertical direction.
The nut 24 that is fastened to the second web 12w is formed as a member in which the conventional reinforcing member 22 and the nut 16 are combined and integrated, and is preferably a cast product of ductile cast iron.

The nut 24 is composed of a base plate portion 24a that abuts the mounting flange 20 that is the member to be fastened, and a bent portion 24b that is formed by bending one end portion of the base plate portion 24a. A disk-shaped raised portion 24c is formed on the shaft 24, and a screw hole 24d into which the screw shaft portion of the bolt 14 is screwed is formed in the raised portion.

On the other hand, the bent portion 24b has a mounting flange 2 for the cross member 18, as well shown in FIG.
The plate portion adjacent to 0, that is, in the case of the illustrated embodiment, abuts on the upper flange 18f, and mainly, the upper flange 18f.
The bending load that acts on the bent portion 26 in which the mounting flange 20 is formed by bending is supported to prevent damage to the bent portion 26. Since the nut 24 is a cast product,
The cross-sectional shape of the connecting portion 24e between the substrate portion 24a and the bent portion 24b can be easily made into an optimum shape capable of preventing stress concentration due to the bending load or at least making the stress concentration degree sufficiently smaller than that of the conventional reinforcing member. Can be molded into.

Further, a curved surface portion 24f having a cross-sectional shape is provided at a tip portion of the bent portion 24b of the cross member 18 which is in contact with the upper flange 18f, and which is gradually separated from the upper flange 18f as it goes inward in the vehicle width direction. .
The curved surface portion 24f is preferably formed into an elliptical surface or a curved surface such as a parabolic surface, a hyperbolic surface, or the like that is close thereto, and by providing the curved surface portion 24f, the upper flange 18 is provided.
It is possible to effectively prevent stress concentration at a portion where f and the tip end of the bent portion 24b come into contact with each other, and reliably prevent cracks or the like in the upper flange 18f at the abutting portion.

According to the above construction, since the nut 24 also serves as a reinforcing member, there are advantages that the number of parts is small, the assembling work of the side rail 12 and the cross member 18 becomes easy, and the manufacturing cost can be reduced. Further, since the nut 24 is a cast product, the shape of the connection portion 24e can be formed into an optimum shape and the curved surface portion 24f can be easily formed. Therefore, damage around the fastening portion of the cross member 18 and the nut 24 can be achieved. There is an advantage that the self-damage can be effectively prevented and eventually the durability and reliability of the chassis frame 10 can be improved.

In the illustrated embodiment, the mounting flange 20 is formed at the end of the upper and lower flanges 18f of the cross member 18 having a groove-shaped cross section, but the end of the web 18w of the cross member 18 is formed. The present invention can be similarly applied to the case where the mounting flange 20 is formed by bending the vehicle body in the front-rear direction. In this case, the bent portion 24b of the nut 24, of course, contacts the plate portion adjacent to the mounting flange, that is, the web 18w.

Further, in the present invention, the cross member 18 has an I-shaped cross-section, and the mounting flanges for the side rails 12 are formed at the ends of the upper and lower flanges or at the ends of the web connecting the upper and lower flanges. In this case, it can be applied in substantially the same manner as the above-mentioned groove-shaped cross-section.

Further, according to the present invention, in an alligator type cross member in which V-shaped connecting portions are formed at both end portions in the vehicle width direction, end portions of an upper member and a lower member forming the connecting portions are vertically moved. The same can be applied to the case where the mounting flange is formed by bending. In this case, the angle formed by the base plate portion 24a and the bent portion 24b of the nut 24 is formed to be an obtuse angle of 90 degrees or more so as to match the angle formed by the plate portions of the upper and lower members adjacent to the mounting flange. Is normal.

[0018]

As described above, the chassis frame fastening nut according to the present invention has a pair of right and left ends in which both ends of a cross member extending in the vehicle width direction extend in the vehicle front-rear direction. Which is fastened to the side rail by a bolt, the nut screwed to the bolt is in contact with the mounting flange of the cross member, and is the same as the base plate portion having a screw hole into which the bolt is screwed. It is characterized in that it is formed by bending at one end of the base plate part and is formed of a cast product having a bent part that abuts a plate part adjacent to the mounting flange of the cross member, and the number of parts is small and the chassis frame of the chassis frame is small. There is an advantage that the manufacturing cost can be reduced and the side rail and the cross member fastening portion can be prevented from being damaged to improve the durability and reliability of the chassis frame.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a front view of a nut 24 in FIG.

FIG. 3 is a partial plan view showing a conventional undercarriage frame for trucks.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 3 and viewed in the direction of the arrow.

[Explanation of reference numerals] 10 Undercarriage frame 12 Side rails 14 Bolts 16 and 24 Nuts 18 Cross members

Claims (1)

[Claims] 1. A structure in which both ends of a cross member that extends in the vehicle width direction are fastened by bolts to a pair of left and right side rails that extend in the vehicle front-rear direction,
The nut screwed with the bolt is formed by bending at one end of the substrate portion and the board portion having a screw hole into which the bolt is screwed and abutting on the mounting flange of the cross member. A fastening nut for a chassis frame, comprising a cast product having a bent portion that abuts a plate portion adjacent to a mounting flange of a cross member.