JPH04306111A - Mounting structure of suspension arm - Google Patents

Abstract

PURPOSE:To prevent the reduction in the axial tension of a fastening bolt for connecting two members by eliminating a gap, when the gap is generated between respective brackets for connecting the two members together. CONSTITUTION:Two bracket parts 12a, 12b formed into open arm are extended from a suspension arm (lower arm) 12 of a suspension cross member. A molding part 100 is provided on one of them, so as to form a female screw part 98. The rigidity of the other bracket part 12a is lower than that of the bracket part 12b on which the female screw part 98 is formed. By having one bracket part 12a deflected at the time of fastening a fastening bolt, its gap is eliminated, and a damage or destruction of the fastening bolt is prevented, and the connection condition between the suspension arm 12 and the suspension cross member is thus kept appropriate. A female screw part 98 can be formed by inserting a tap from an insert hole 102 of the bracket part 12 on which no female screw part 98 is formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting a suspension arm, and more particularly to a structure for mounting a suspension arm to a suspension cross member mounted on a vehicle body.

0002

2. Description of the Related Art An automobile suspension system is composed of a link mechanism consisting of several suspension arms, each of which is directly or indirectly connected to a wheel, and which is connected to a suspension cross member attached to the vehicle body. Connected to other parts of the vehicle body. In the case of such a structure, for example, in order to connect the lower arm to the suspension cross member with a tightening bolt and support it on the cross member, the lower arm is provided with two crotch-shaped brackets, and a cross is connected between the brackets. The protruding portions of the members are fitted to allow the tightening bolt to be inserted between the bracket portions. For example, Jitsukai Hei 2
JP-A-128608 describes a suspension device having such a configuration.

0003

[Problem to be Solved by the Invention] When tightening a tightening bolt between bracket parts as described above, it is necessary to screw a nut onto the end of the tightening bolt that protrudes outside the facing bracket parts. Normally, the two bracket parts are not made to have different thicknesses. Therefore, if a gap occurs when the protrusion of the cross member is fitted between the bracket parts, both bracket parts will bend due to the fastening force of the tightening bolt. At that time,
The mounting position of the lower arm may shift slightly to the left or right with respect to the cross member fixed to the vehicle body, and the mounting position relative to the vehicle body differs depending on the vehicle body, resulting in variations in the mounting condition. There is. As a result, the force acting on the tightening bolt may become unbalanced, or unnecessary force may be applied to the suspension arm, leading to a problem of premature damage to the tightening bolt. The present invention has been made in view of the above-mentioned circumstances, and its purpose is to eliminate the gap between the above-mentioned bracket parts so as to connect members such as a cross member to a member such as a suspension arm. By ensuring that the bolts can be mounted accurately and preventing the occurrence of gaps, it is possible to avoid a decrease in the axial force or damage to the tightening bolts that connect the two parts, and to improve the rigidity of the bolts in the mounted state. An object of the present invention is to provide a suspension arm mounting structure that realizes the following.

0004

SUMMARY OF THE INVENTION The present invention is applied to a structure for attaching a suspension arm to a suspension cross member. Its feature is that, referring to FIGS. 1 and 2, two crotch-shaped bracket portions 12a and 12b extend from the suspension arm 12 or the suspension cross member 1. and,
A female threaded portion 98 is formed by providing a fleshed portion 100 on one of the two bracket portions 12a and 12b, and the rigidity of the other bracket portion 12a is lower than that of the bracket portion 12b on which the female threaded portion 98 is formed. That is what we are doing. Incidentally, the female threaded portion 98 is formed by inserting a tap into the insertion hole 102 of the bracket portion 12a where the female threaded portion 98 is not formed, and is expanded to have approximately the same diameter as the insertion hole 102 opened by the tap in the lower part of the neck. It is preferable that the tightening bolt 14 having the diameter portion 103 be screwed into the female threaded portion 98 through the insertion hole 102 .

[0005]

[Operation] The suspension arm 12 is formed with two crotch-shaped bracket portions 12a and 12b that fit into a portion of the suspension cross member 1. A portion of the suspension cross member 1 is supported by a tightening bolt 14 via the bracket portions 12a, 12b. A female threaded portion 98 is formed on the bracket portion 12b side,
The tightening bolt 14 can be screwed on. The bracket parts 12a and 12b have different thicknesses so as to have different rigidities. The bracket parts 12a, 12
When a part of the suspension cross member 1 is fitted between the brackets 12a and 12b, a gap may occur between that part and each of the bracket parts 12a and 12b due to assembly errors or manufacturing errors. When the tightening bolt 14 is tightened, the bracket part 12a in which the female thread part 98 is not formed is bent, and there is no gap between each bracket part 12a, 12b and the suspension cross member 1 to be fitted. Therefore, the tightening force is prevented from decreasing or loosening due to plastic deformation of the tightening bolt 14, which would occur if there is a gap. Since the bracket part 12b is formed with the female screw part 98, a thickened part 100 is provided, and the rigidity of this part is inevitably high, so that only the bracket part 12a is bent. By the way, the bracket part 12
When carving a female threaded portion 98 in b, if the female threaded portion 98 extends in a direction toward the rear of the suspension arm 12, a tap for thread cutting must be inserted from the bracket portion 12a side in the direction of arrow 101. Sometimes there isn't. In thread cutting work in such a case, the insertion hole 102 on the bracket part 12a side into which the body of the tap is inserted becomes larger than the diameter of the female thread part 98, so that when tightening the tightening bolt 14 into the female thread part 98, , the tightening bolt 14
The lower part of the neck will play in the insertion hole 102. Therefore, as the tightening bolt 14, a bolt having an enlarged diameter portion 103 equal to the body diameter of the tap in the lower neck portion is adopted. This allows the tightening bolt 14 to be tightened into the bracket portion 12.
a, 12b, the enlarged diameter portion 103 aligns with the insertion hole 102 of the bracket portion 12a created by the tap, and centering of the tightening bolt 14 is automatically achieved. The work of tightening the tightening bolt 14 is also simplified. Furthermore, damage or breakage of the tightening bolt 14 due to bending force generated under the neck of the tightening bolt 14 is also suppressed. Incidentally, by fitting a part of the suspension cross member 1 between the bracket parts 12a and 12b,
When the tightening bolt 14 is tightened, the suspension cross member 1 side is mounted based on the inner surface of the bracket part 12b, so that the mounting position of the suspension arm 12 with respect to the suspension cross member 1 is not misaligned, and there is no variation in the mounting structure. A connected state is achieved.

[0006]

According to the present invention, the axial force of the tightening bolt can be prevented from decreasing and the rigidity of the female threaded portion can be increased. A gap inevitably occurs between the fitting member and the bracket part, but by bending one bracket part when tightening the tightening bolt, this gap can be eliminated and damage to the tightening bolt can be prevented. , it is possible to properly maintain the connection state between the suspension arm and the suspension cross member. When forming a female thread on a bracket part, it is possible to insert a thread cutting tap from one bracket part to the other bracket part, but if it is not possible to cut the thread from the opposite direction, the tap for thread cutting can be inserted into the female thread part. When the tap is inserted into the bracket part that is not provided, the insertion hole becomes larger than the diameter of the female thread part. However, the enlarged diameter portion of the lower neck portion of the bolt that connects the suspension arm and the suspension cross member matches the diameter of the insertion hole, and the tightening bolt is automatically centered. Moreover, since the bolt does not play in the insertion hole, fatigue failure of the bolt is also prevented.

[0007]

EXAMPLES The present invention will be explained in detail below based on examples. FIG. 5 shows a plan view of the right half of the multi-link suspension system and suspension cross member on the front side of the vehicle body. FIG. 6 is a rear view, and FIG. 7 is a side view thereof. In addition, the upper side in FIG. 5 is the front side of the vehicle body, and the lower side is the rear side. A first cross member provided at a front position supporting an engine (not shown) and a second cross member 1 provided at a rear position are installed as suspension cross members. The second cross member 1 is an aluminum die-cast product, and has an arm portion 3 protruding from a main body portion 2, and has one hole 4 on the front side and two holes 5 and 6 on the rear side. There is. Then, insert the stud bolts 7 and bolts 8, 9 shown in FIG. 6 into the respective holes 4, 5, and 6, and insert the stud bolts 7 and bolts 8, 9 shown in FIG. , the second cross member 1 can be fixed. The front attachment part 10 (see FIG. 5) and the rear attachment part 1 of the second cross member 1
1, an intermediate bent portion 12A and a rear end portion 12B of a lower arm 12 of the suspension device are attached. This lower arm 12 is also an aluminum die-cast product, and is a link formed in a substantially A-shape, and the above-mentioned intermediate bent portion 12A corresponds to the top of the A-shape. A rubber bush 13 is inserted into the front attachment part 10, and a collar (not shown) is attached therein. The front mounting portion 10 is fitted into two crotch-shaped bracket portions 12a and 12b of the intermediate bent portion 12A of the lower arm 12, and both 10 and 12 are connected by a tightening bolt 14. The rear mounting part 11 has a shaft hole part 1.
5, and a liquid seal type bush 16 attached to the rear end portion 12B of the lower arm 12 is interposed therein. A body frame 59 (
(see Fig. 10), and the rear part 5 of its body frame 59
It is fixed to the lower surface of 9B with two bolts 8 and 9 on the rear side (see FIG. 6). On the other hand, the hole 4 on the front side of the second cross member 1 is provided in a rising portion 18 bent obliquely upward from the main body portion 2. A front portion 59A of the vehicle body frame 59 is located above the hole 4 on the front side, and is fixed to the lower surface thereof with the stud bolt 7 described above. In addition, the rising part 1
An upper arm 19 of a suspension device is attached to the link attachment portion 18a at the tip of the suspension device 8. A steering rack device 17 for steering, which will be described later, is provided on the second cross member 1, and a steering rack gear 38 shown in FIG. 9 is built therein, and a rack case 20 for this purpose is attached as shown in FIG. There is. At the end of the steering rack bar 21 is the tie rod 22.
is connected to the wheel support 24 of the front wheel 23. Therefore, if you turn the handle, the tie rod 22
The direction of the front wheel 23 can be changed by moving left and right. A pipe-shaped stabilizer 25 extending left and right at the rear of the suspension device is, as shown in FIG.
It is connected to the lower arm 12 via a rod 26 protruding from an intermediate boss portion 97 of the lower arm 12. The stabilizer 25 is attached to the second cross member 1 with a mounting bracket 27 (see FIG. 5) at the center of the arm portion 3 of the second cross member 1 via a rubber 28 (see FIG. 7). The rack case 20 described above is fixed to the bracket 90 at the center of the main body 2 of the second cross member 1. suspension damper 29
The lower fork member 30 (see FIG. 6) is connected by fitting the pin 31 at the lower end into the support portion 89 near the end of the lower arm 12. A ball joint 32 is provided at the end of the lower arm 12 via an overhang 96, and via the ball joint 32,
The lower arm 12 is connected to the wheel support 24. Note that the fork member 30 is bent into a dogleg shape, and a space 33 for passing an output shaft (not shown) for a front-wheel drive vehicle is secured. Incidentally, the fork member 30 is manufactured separately from the damper main body 29A of the suspension damper 29, and is connected to the connecting portion 77 shown in FIG.
, the mounting bolt 34 (represented by a dashed line)
It is now fixed in place. A rising extension arm 35 shown in FIG. 6 is provided from the wheel support 24 described above, and a trailing arm 36 is connected thereto. The rear end portion 36a is directly attached to the vehicle body. The steering rack device 17 is mounted directly on the second cross member 1. The vehicle of this example is equipped with a four-wheel steering system. The four-wheel steering device is designed to align the rear wheels with the front wheels 23 so that they are in opposite phase or in phase to make it easier to turn in a tight corner or change lanes at high speed. An intermediate shaft 37 (see FIG. 11) is provided to transmit the steering angle made by the front wheels 23 to the rear wheels.

The lower arm 12 described above is approximately A-shaped as shown in FIG.
, there are two crotch-shaped bracket parts 12a, 12 that fit into the front mounting part 10 (see FIG. 5) of the second cross member 1.
b is formed. That is, the second cross member 1
A cylindrical portion forming a front mounting portion 10 is supported by a tightening bolt 14. A female threaded portion 98 is formed on the bracket portion 12b side, and the tightening bolt 14 is screwed into the female threaded portion 98. The bracket parts 12a and 12b have different thicknesses so as to have different rigidities. When fitting the front side attachment part 10 of the second cross member 1 between the bracket parts 12a, 12b, there is a gap between the front side attachment part 10 and each bracket part 12a, 12b due to assembly error or manufacturing error. may occur. In addition, a bracket portion 1 is provided inside the front mounting portion 10.
Since the collar 99 extending between the bracket parts 12a and 12b is built in as shown in FIG. However, when tightening the tightening bolts 14, make sure that there is no gap between each bracket part 12a, 12b and the front mounting part 10, otherwise the tightening bolts 14 will become loose while driving the car. As a result of plastic deformation, the fastening force decreases or loosens. Therefore, when the front mounting portion 10 is attached to the intermediate bent portion 12A and the tightening bolt 14 is tightened, it is necessary to eliminate the gap. To this end, when the tightening bolt 14 is tightened, the bracket portion 12a in which the female threaded portion 98 (see FIG. 1) is not formed is bent. Since the female threaded portion 98 is formed in the bracket portion 12b, there must be a fleshed portion 100, which inevitably increases its rigidity, and it is the bracket portion 12a that can be bent. Therefore, the thickness of the bracket part 12a that does not require the formation of a female thread is the same as that of the bracket part 12b.
It is thinner than that. By the way, the bracket part 12b
When the female threaded portion 98 is carved in the lower arm 12, the female threaded portion 98 is oriented in a direction extending toward the rear of the lower arm 12.
A tap (not shown) for thread cutting is attached to the bracket part 12a.
It has no choice but to insert from the side in the direction of arrow 101. In such thread cutting work, the insertion hole 102 on the bracket part 12a side into which the body of the tap is inserted is inserted into the female thread part 98.
becomes larger than the diameter of In this case, when the tightening bolt 14 is tightened into the female threaded portion 98, the lower neck portion of the tightening bolt 14 will play in the insertion hole 102. Therefore, as shown in FIG. 2, the tightening bolt 14 has an enlarged diameter part 10 equal to the body diameter of the tap at the lower neck part.
3 will be adopted. Thereby, when inserting the tightening bolt 14 into the bracket parts 12a, 12b,
The enlarged diameter portion 103 matches the insertion hole 102 of the bracket portion 12a created by the tap, and the tightening bolt 1
4 centering can be achieved, and the work of tightening the tightening bolt 14 is also simplified. Furthermore, damage or breakage of the tightening bolt 14 due to bending force generated under the neck of the tightening bolt 14 is also suppressed. The cylindrical structure of the front attachment part 10 of the second cross member 1 is shown in FIG.
Referring to FIG. 1, a rubber bush 13 is built into the cylindrical body 104. This rubber bush 13 consists of a cylindrical bush 13A and a plate-shaped bush 13B. Incidentally, what appears in FIG. 5 is the plate-shaped bush 13B. A collar 99 is interposed in the rubber bush 13 and has a length that slightly protrudes from both ends of the rubber bush 13. The collar 99 has an enlarged diameter on the plate-shaped bush 13B side, and the cylindrical bush 13
A conical surface 105 is formed between the portion inserted into A and the portion inserted into A. If such a conical surface 105 is provided, an inclined facing part will be formed between it and the cylindrical bush 13A.For example, as a characteristic of the rubber bush 13 when longitudinal force is applied to the wheel, the spring It is convenient because the constant changes are linear. That is, when the rubber bush 13 is gradually twisted, the hardness, ie, spring constant, of the rubber bush 13 exhibits a characteristic that rises from a gradual rise to a sudden rise with respect to the twist angle, as shown by the broken line in FIG. Common. However, the above conical surface 1
By providing 05, the characteristic can be brought closer to exhibiting a uniform rate of increase as shown by the solid line, which is convenient. By the way, a cylindrical core material 106 made of a metal material is interposed in the above-mentioned cylindrical bush 13A. As a result, the hardness of the rubber bush 13 can be tuned, and the rubber bush 13 can be made hard in the lateral direction and soft in the front-rear direction. Therefore, in order to improve steering stability when turning the steering wheel, the steering wheel is made stiffer in the lateral direction. If the front and back directions are made soft, the force that pushes the wheels backwards when they go over a protrusion is tolerable to some extent, which has the advantage of making the ride more comfortable. Note that the core material 106 is molded at the time of manufacturing the cylindrical bush 13A. Incidentally, although not shown, when the front mounting part 10 of the second cross member 1 is fitted between the bracket parts 12a and 12b and the tightening bolt 14 is tightened, the collar 9
Both ends of the bracket 9 abut against the inner surfaces of the respective bracket portions 12a and 12b, thereby restricting the deflection of the bracket portion 12a. Therefore, excessive deformation of the bracket portion 12a is prevented, and the front attachment portion 10 and the bracket portion 12a are prevented from deforming excessively.
a and 12b will be fastened without leaving any gaps. Moreover, since the bracket part 12b side does not bend, the collar 99 is attached with reference to the inner surface of the bracket part 12b, and the lower arm 12 is installed in a stable position without any distortion in the mounting position of the lower arm 12 relative to the front mounting part 10. The advantage is that the connection status is maintained.

Incidentally, the above-mentioned stabilizer 25 is fixed on the left and right arms 3, 3 (only the right side is shown) of the second cross member 1, as shown in FIG. The second cross member 1 will be described below with reference to FIGS. 5 and 8. The second cross member 1 has its main body 2
In contrast, the two arms 3, 3 are U-shaped in plan view and extend backward, so the arms 3 tend to be thin and weak compared to the main body 2. . A rear attachment portion 11 is formed at the rear end of this arm portion 3, and a rear end portion 12B of a lower arm 12 as a suspension arm is attached to the rear attachment portion 11. enters. When that impact hits,
Since the arm portion 3 is thin, it is easily bent or deformed. Therefore, this arm portion 3 is reinforced with a connecting rib 91 extending from the main body portion 2, as also shown in FIG. Note that the arm portion 3 has a triangular shape and tapers toward the inside of the vehicle body. The above-mentioned connecting ribs 91 increase the rigidity of the cantilever-like arm portion 3 at which the lower arm 12 is attached. A mounting seat 92 for fixing the stabilizer 25 is formed on the upper surface of the connecting rib 91, and is designed to increase the mounting rigidity of the stabilizer 25 on the reinforced arm portion 3 when it is fixed with the mounting bracket 27. There is. That is, the reinforcement applied to the arm portion 3 to support the lower arm 12 also serves as reinforcement for attaching the stabilizer 25. The stabilizer 25 causes the arm portion 3 to exert an action to counter torsion when the vehicle rolls, thereby stopping the roll. Therefore, this stabilizer 25
Although a large force acts on the mounting portion of the stabilizer 25, it is possible to cope with the force by the reinforcing action of the connecting rib 91 without actively reinforcing the mounting seat 92 of the stabilizer 25. That is, there is no need to reinforce the mounting portion of the stabilizer 25 just for this purpose, which is convenient. The mounting fitting 27 (see FIG. 7) has a substantially Ω-shape, and is placed over the stabilizer 25 on the mounting seat 92 and fixed with bolts 93a and 93b, as shown in FIG. In addition, the stabilizer 25 and the mounting bracket 2
7, a rubber 28 is interposed to provide a buffer. On the other hand, a bracket 90 for fixing the rack case 20 is attached to the upper surface of the main body 2 of the second cross member 1. Further, a projecting portion 94 for attaching a hanger (not shown) for holding a silencer is integrated into the lower part of the arm portion 3 inside the vehicle body. Note that holes 95A and 95B are connected to this projecting portion 94 via rubber (not shown).
The silencer can be hung by inserting a bolt (not shown) into the frame. Incidentally, in FIG. 8, the overhanging parts 94 are formed on the left and right sides, but only the necessary ones are used. By the way, the bolts 93a in the mounting bracket 27 for attaching the stabilizer 25 described above,
93b and the bracket 90 that fixes the rack case 20
Bolts 90a and 90b are screwed in from above in a vertical position, and holes 95A and 95 are provided for hanging the silencer.
The bolt screwed into B is inserted vertically from below. This is to improve the installation workability when automatically mounting the subassembly of the second cross member 1 using a robot or the like. In other words, if the bolt is installed in an inclined position, the movement of the robot will become complicated and the drive device for screwing it will be impossible to arrange, but this can be avoided. It is considered. Therefore, it becomes possible to improve the assembly work efficiency when using a robot or the like.

Three holes 4, 5, and 6 shown in FIG. 5 are provided on the front and rear sides of the second cross member 1, and stud bolts 7 and bolts 8 shown in FIG. , 9 are inserted, and the second cross member 1 is fixed to the side frame 59 shown in FIG. 10 at a total of six hole positions on the left and right sides. The side frame 59 is attached to the right side of the vehicle body, and the upper part in the figure corresponds to the front side of the vehicle body, the lower part corresponds to the rear side, the left part is the inside of the vehicle body, and the right part is the outside of the vehicle body. The lower threaded portion 7a of the stud bolt 7 shown in FIG. 10 is inserted into the hole 4 on the front side of the second cross member 1 shown in FIG. In addition, the stud bolt 7
The location corresponds to the upper part of a tire house (not shown) that secures and covers the tire relief part 71 that enables steering of the front wheels. Note that, after passing the stud bolt 7 through the hole 4 on the front side of the second cross member 1, the second cross member 1 is fixed to the side frame 59 by tightening the nut 62 shown in FIG. Since the second cross member 1 is attached to the side frame 59 in this manner, the strength of the side frame 59 is improved even if the front portion 59A of the side frame 59 is narrow. A torque box 67 installed between the rear portion 59B of the side frame 59 and the outer plate 66 is integrated by welding or the like. This torque box 67 is made of a plate material in a box shape to form a space 68 with a closed cross section (the torque box 67 is shown in the figure).
(only the front and bottom surfaces are visible), the torsional rigidity of the entire vehicle body has been improved. Two nuts 69 and 70 are fixed to the bottom of the side frame 59 on the inside where the torque box 67 is located. This nut 69,
Reference numerals 70 correspond to the two holes 5 and 6 on the rear side of the second cross member 1 shown in FIG. I have to. In this way, the rigidity is increased by coupling the torque box 67 and the side frame 59, and the rigidity of the entire vehicle body is also improved. In addition, since the width of the front part 59A of the side frame 59 is narrow, the second cross member 1 can be fixed with one stud bolt 7, and the rear part 59B can be secured to some extent with a torque box 67, so two It is fixed by bolts 8 and 9.

When mounting the engine 48 shown in FIG. 11 on the suspension cross member, if it is made wider,
This is advantageous in suppressing the vibration. That is, it can contribute to lowering the spring constant of the entire vehicle body. However, it is not preferable to use a large suspension cross member because it increases weight. For this purpose, the center member 51, which has been considered in the past, is employed. That is, the first cross member 5 on the front side serves as a suspension cross member.
0 and a second cross member 1 on the rear side are provided, and a center member 51 as an engine mount member is attached between both cross members 1 and 50. The front part of the engine 48 is supported by the center member 51. By the way, considering the position of the center of gravity of the entire vehicle body, in the case of a front-wheel drive vehicle, the engine 4 mounted at the front
8 is preferably placed as far back as possible. Preferably, if the engine 48 is lowered to where the front wheels 23 are located, the steering characteristics will be improved. That is, if the engine 48 is placed too far in the front, the vehicle will become front-heavy, making it difficult for the vehicle to turn. Therefore, when the engine 48 is lowered rearward, there is no place to provide the second engine mount 47 that supports the rear part of the engine 48. Therefore, the second engine mount 47 is attached to the main body portion 2 of the second cross member 1. On the other hand, the front side of the engine 48 is supported by a first engine mount 49 provided at the front portion of the center member 51. Then, the center member 51 is extended forward so that the front end of the center member 51 is located as far forward as possible, and the first engine mount 4 on the center member 51 is
The mounting position of 9 is closer to the first cross member 50. The hardness of each mount rubber 123, 124 is selected so that the spring constant of the first engine mount 49 is larger than the spring constant of the second engine mount 47 located at the rear. This is because the engine 48 is moved as far back as possible.
This is done in consideration of the fact that the load sharing in the first engine mount 49 becomes smaller. The second cross member 1 has a front hole 4 and a rear hole 5 provided on the left and right sides.
, 6 to the side frame 59 shown in FIG. 10. Therefore, the distance between the third engine mount 52 on the right side and the fourth engine mount 53 on the left side becomes large. Therefore, the engine 48 can be widely mounted, and engine vibration can be suppressed. As mentioned above, the support on the second engine mount 47 is made soft, and this suppresses the transmission of vehicle body vibrations to the passenger side through the center member 51, which must maintain as high rigidity as possible. There is. On the other hand, since the first engine mount 49 is made of hard rubber, vibrations are absorbed by the rear second engine mount 49.
7 to the first engine mount 49. Furthermore, since the first engine mount 49 is located further away from the occupant's position, even if the vibration there is large, the effect on the occupant is reduced. By the way, when vibration enters from the front wheels 23, the first engine mount 49 tends to become an antinode, and the second engine mount 47 tends to become a node, considering the vibration mode of the vehicle body. Therefore, the second engine mount 4
The support at point 7 is not made too hard to make it difficult for vibrations to be transmitted. Also, engine 4
8, a pipe member 125 is adopted for the rear half of the center member 51 because there are problems with cooling performance and exhaust, and there is no need to support a large load. On the other hand, the front half of the center member 51 is provided with a plate-shaped bracket member 126 connected to the pipe member 125, forming a flat surface and forming a flat surface for the first engine mount 49.
I am trying to make it possible to post it.

According to the above-described structure, the lower arm 12 shown in FIG.
Two crotch-shaped bracket parts 12a and 12b that fit into the
are formed, and the front mounting portion 10 of the second cross member 1 is supported by a tightening bolt 14 (see FIG. 2) via these bracket portions 12a and 12b. A female threaded portion 98 is formed on the bracket portion 12b side, and the tightening bolt 14 can be screwed thereon. The bracket parts 12a and 12b have different thicknesses so as to have different rigidities. However, the bracket part 12a
, 12b, a gap may occur between that part and each bracket part 12a, 12b due to assembly error, manufacturing error, or the like. When tightening the tightening bolts 14, make sure that there is no gap between each bracket part 12a, 12b and the front mounting part 10, and prevent the tightening force from decreasing or loosening due to plastic deformation of the tightening bolts 14. This prevents At this time, when the tightening bolt 14 is tightened, the bracket portion 12a in which the female thread portion 98 is not formed is bent. Since the bracket portion 12b is formed with the female screw portion 98, there is a thickened portion 100, and the rigidity of this portion is inevitably high. Therefore, only the bracket portion 12a is bent as described above. On the other hand, when carving the female threaded part 98 on the bracket part 12b, since the female threaded part 98 extends in the rearward direction of the lower arm 12, a tap (not shown) for thread cutting is inserted from the bracket part 12a side in the direction of the arrow 101. Sometimes you have no choice but to insert it. In thread cutting work in such a case, the insertion hole 102 on the bracket part 12a side into which the body of the tap is inserted becomes larger than the diameter of the female thread part 98, so that when tightening the tightening bolt 14 into the female thread part 98, In addition, the lower neck portion of the tightening bolt 14 will play in the insertion hole 102. Therefore, as shown in FIG. 2, the tightening bolt 14 is provided with an enlarged diameter portion 103 equal to the body diameter of the tap at the lower neck portion. As a result, when the tightening bolt 14 is inserted into the bracket parts 12a and 12b, its enlarged diameter part 103 matches the insertion hole 102 of the bracket part 12a created by the tap, and the center ring of the tightening bolt 14 naturally aligns with the insertion hole 102 of the bracket part 12a created by tapping. It will be done. The work of tightening the tightening bolt 14 is also simplified. Furthermore, damage or breakage of the tightening bolt 14 due to bending force occurring under the neck of the tightening bolt 14 is also avoided. Incidentally, a part of the second cross member 1 is connected to the bracket part 12a,
12b and tighten the tightening bolt 14,
The second cross member 1 side is mounted based on the inner surface of the bracket portion 12b, and the mounting position of the lower arm 12 with respect to the second cross member 1 is not misaligned.
A connection condition with no variation in installation is achieved.

In the above description, two crotch-shaped bracket parts 12a and 12b are provided protruding from the lower arm 12, and the front mounting part 10 of the second cross member 1 is fitted between them. , its front mounting part 1
Although not shown in the figure, the same effect can be achieved by forming two crotch-shaped bracket parts and providing the lower arm 12 with a cylindrical part that fits between the bracket parts. can. Further, although the lower arm 12 has been described as an example of a suspension arm, the above-described connection structure can also be applied to an upper arm or the like and a member to which it is coupled.

[Brief explanation of drawings]

[Fig. 1] Plan view of the suspension arm.

[Figure 2] Enlarged view of the tightening bolt.

FIG. 3 is an enlarged cross-sectional view of the main parts of the front attachment part of the suspension cross member.

FIG. 4 is a graph showing changes in the torsion angle and its spring constant in the rubber bush.

[Fig. 5] A plan layout diagram of the suspension device and the suspension cross member.

[Fig. 6] Rear arrangement view of the suspension device and suspension cross member.

[Fig. 7] Side layout diagram of the suspension device and suspension cross member.

FIG. 8 is a plan view of the second cross member.

FIG. 9 is a view taken along line B-B in FIG. 11.

FIG. 10 is a perspective view of a side frame attached to the right side of the vehicle body.

FIG. 11 is a plan view of the engine mounted on the suspension cross member.

[Explanation of symbols]

1... Suspension cross member (second cross member), 12... Suspension arm (lower arm),
12a, 12b...bracket part, 14...tightening bolt, 9
8... Female threaded part, 100... Thickened part, 102... Insertion hole, 1
03... Expanded diameter part.

Claims (2)

[Claims] Claim 1: In a structure in which a suspension arm is attached to a suspension cross member, two crotch-like bracket portions are extended from the suspension arm or the suspension cross member, and one of the two bracket portions is provided with a fleshed portion. A mounting structure for a suspension arm, characterized in that the other bracket part has a female threaded part formed therein, and the rigidity of the other bracket part is lower than that of the bracket part in which the female threaded part is formed. 2. The female threaded portion is formed by inserting a tap into the insertion hole of the bracket portion where the female thread is not formed, and the tightening bolt that is screwed into the female threaded portion through the insertion hole is formed in the lower neck portion of the female threaded portion. 2. The suspension arm mounting structure according to claim 1, further comprising an enlarged diameter portion having substantially the same diameter as the insertion hole opened by the tap.