JPH1035210A - Axle suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the height of a casting mold and to insure the shape as desired without cutting work, even in the case of molding by casting. SOLUTION: Parting surfaces 53, 57 between a lower mold 51 and an upper mold 52, both of which form a middle part 21 and a knuckle spindle installing part 23R of an axle member, are formed so as to coincide with the fore-and-aft center line (C) of the axle member, while a parting surface 55 of a leaf spring installing part 22R is formed at the afer end of the installing part 22R. With this, since the upper surface of the leaf spring installing part 22R can take a plane form as desired, machining such as cutting work can be dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called rigid axle suspension in which left and right wheels are connected by a single axle and the axle is attached to a vehicle body via a spring.

[0002]

2. Description of the Related Art A suspension is a device that connects a wheel to a vehicle body and is an important device that supports the vehicle body and has a great effect on the vibration, riding comfort, and security of the vehicle.
The structure consists of a spring that reduces the impact received from the road surface during traveling, a shock absorber that suppresses the vertical vibration of the vehicle body to improve the ride comfort, a stabilizer that suppresses the rolling of the car, and holds these to control the movement of the wheel It consists of a link mechanism to suppress.

This device has desirable spring characteristics and damping characteristics in order to support the vehicle body and reduce vibrations and impacts from the road surface, protect the vehicle body, occupants, loads, etc., and provide a driving force during acceleration / deceleration.・ Appropriate rigidity and sufficient strength / durability against braking force or force in all directions such as lateral force when turning, holding the wheel in a predetermined correct position with respect to the vehicle body, and By appropriately controlling the movement of the wheels with respect to the road surface, a function that gives the vehicle the most suitable kinetic performance is required. For this reason, various types of suspensions have been considered.

[0004] As one of them, there is an axle suspension system, so-called rigid axle suspension. In this type, the left and right wheels are connected by a single axle, and the axle is attached to the vehicle body via a spring. Usually, a suspension (suspension device) supporting the vehicle body and an axle (traveling device) supporting the wheels are provided. ). The axle receives a vertical load applied to the spring seat, a vertical bending moment due to a lateral load during turning or the like, a horizontal bending moment and a torsional moment due to a braking force and a driving force. This type of suspension is often used for front and rear shafts of trucks, buses and the like.

[0005] Among the rigid axle suspensions, in the case of a non-drive wheel, the rigid axle suspension is an axle beam (I-beam), which is formed in an I-shaped cross section by forging. The axle beam formed on the I-shaped cross section by forging has high fatigue strength, deformation strength and impact resistance, and is a manufacturing method suitable for mass production.

[0006]

The above-described forging has a problem that it is difficult to make changes corresponding to each vehicle type because the manufacturing equipment is large and the forging die is also large. Therefore, a cast axle beam excellent in strength and weight reduction is disclosed in
It has been proposed in JP-A-215004. This one is
The axle beam is formed into a rectangular cross-section by casting, and the parting-off portion is provided on the side surface of the axle beam, so that strength equivalent to that of forged axle beam can be obtained and weight reduction is to be achieved. .

However, in the above-described cast axle beam, since the parting-off portion is cast so as to be provided on the side surface of the axle beam, as shown in FIG.
The upper and lower center lines 1a of the mold 2 need to be parting surfaces (parting surfaces) 3 between the lower mold 2a and the upper mold 2b. Here, since the axle member 1 is curved upward from the center to both ends, the vertical center line 1a of the axle member 1
Becomes the parting surface (parting surface) 3 of the mold 2, the height of the lower mold 2a and the upper mold 2b needs to be increased, so that the overall height of the mold 2 increases. As a result, when the mold 2 is divided, the height on the side of the manufacturing equipment is also increased, which causes a problem that the productivity of the axle member 1 is reduced. Accordingly, the present invention has been made in view of the above-described problems, and it is an object of the present invention to reduce the height of a casting mold and to secure a required shape without cutting even in casting. .

[0008]

SUMMARY OF THE INVENTION The present invention relates to an axle suspension device having an axle member extending in a vehicle width direction, connecting left and right wheel supports, and suspending a vehicle body. According to the first aspect of the present invention, the axle member is formed by casting, and is formed so as to be curved upward at the end toward the wheel support. The reason is that a parting-off part is provided.

In the invention described in claim 2, the axle member includes a suspension spring mounting portion for arranging a suspension spring on upper and lower surfaces, and the parting portion is provided on upper and lower surfaces of the axle member other than the suspension spring mounting portion. It is to be provided.

[0010]

According to the first aspect of the present invention, when the parting portions are formed on the upper and lower surfaces of the axle member, the end portions of the axle member are curved upward toward the axle support. However, since the mold can be formed without increasing the height of the mold, the productivity of this type of axle member is improved. When the parting-off part is provided on the upper and lower surfaces of the axle member other than the suspension spring attachment part, the parting-off part is not formed on the suspension spring attachment part, so that the upper part of the upper surface of the suspension spring attachment part is not formed. Since the surface shape is formed flat, a post-process such as cutting is not required, and the working process can be simplified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an axle suspension according to the invention in F
FIG. 1 is a perspective view showing an overall configuration of the present embodiment when applied to a front side (non-drive wheel side) rigid axle suspension of an R vehicle. The rigid axle suspension includes an axle member 20 connecting the left wheel support 10L and the right wheel support 10R, and a pair of leaf springs 30L disposed in the front-rear direction with respect to the axle member 20.
30R. These leaf springs 3
One end 31L, 31R of the 0L, 30R is pin-connected to a spring bracket fixed to the vehicle body side, and the other end is provided with shackles 32L, 32R for releasing a change in span due to deflection of the leaf springs 30L, 30R. The axle member 20 and the leaf springs 30L, 30R are connected by U bolts 33, 33, 33, 33. Axle member 20
Shock absorbers 40L and 40R are mounted near both ends of the.

FIG. 2 is a view showing the structure of the axle member 20, FIG. 2 (a) is a top view of a half of the axle member 20, and FIG. 2 (b) is a side view of the half. 3 shows a sectional view, FIG. 3 (a) shows a sectional view taken along the line AA of FIG. 2 (b), and FIG. 3 (b) shows a sectional view taken along the line BB of FIG. 2 (b). The axle member 20 has a leaf spring attachment portion 22L for attaching a leaf spring (see FIG. 1) to both ends of a central portion 21 formed substantially horizontally (note that FIG.
2L is not shown), 22R, and knuckle spider mounting portions 23L for mounting knuckle spiders for steering wheels at both ends (note that 23L is not shown because FIG. 2 shows the right half portion). ) And 23R.
Here, the knuckle spindle attachment portions 23L and 23R are formed to be curved upward from the leaf spring attachment portions 22L and 22R, respectively.

FIG. 4 is a view showing a mold 50 for forming the axle member 20 by casting. The mold 50 includes a lower mold 51 and an upper mold 52, and a parting surface (cut surface) 53 of the lower mold 51 and the upper mold 52 forming the central portion 21 of the axle member 20, and a knuckle spider mounting portion 23 </ b> R (note , 23L) are formed such that the parting surfaces 57 of the lower die 51 and the upper die 52 that are formed coincide with the front-rear center line C of the axle member 20. On the other hand, the leaf spring mounting portion 22R
(The same applies to 22L).
A parting surface 55 of the upper die 52 and the upper die 52 is formed at a rear end thereof (in FIG. 4, the lowermost part of the leaf spring mounting portion 22R). In addition, a parting surface 54 obliquely rearward (diagonally lower in FIG. 4) is between the parting surfaces 53 and 55, and a parting surface 56 diagonally forward (diagonally upper in FIG. 4) is between the parting surfaces 55 and 57. Are formed respectively.

As described above, since the parting surface 53 is formed on the upper and lower surfaces of the axle member 20, the axle member 20
Even if is curved upward at the end, the height of the mold can be kept low, and the height on the side of the manufacturing equipment in the mold splitting operation is reduced, thereby improving the working efficiency. Further, as shown in FIG. 2A, the axle member 20 has a parting part 21 x by a parting surface 53, a parting part 22 y by a parting surface 54, a parting part 22 x by a parting surface 55, and a parting part by a parting surface 56. The part 22z has the parting part 23x formed by the parting surface 57, and the upper surface 22a of the leaf spring mounting parts 22R and 22L has a predetermined planar shape, and is subjected to machining such as cutting. Eliminates the need.

The leaf spring mounting portions 22R, 2
Since the die draft formed on the upper surface of the 2L can be utilized as a taper angle for attaching a leaf spring, it is necessary to use a caster wedge which has been conventionally used for forming a taper angle. And the cost can be reduced.

Further, in the casting method, if a weir is provided on the upper side surface 22b of the leaf spring mounting portions 22R, 22L so as not to interfere with the leaf spring, the work for removing the remaining weir becomes unnecessary. The workability is improved, and the cost can be further reduced.

In the above-described embodiment, the cut-off surfaces 53 and 57 coincide with the front and rear center lines of the axle members of the center portion 21 and the knuckle spider mounting portions 23R and 23L.
Is described, and the parting plane 55 is formed at the rear end of the leaf spring mounting parts 22R, 22L. However, the parting plane 55 is formed at the rear end or the front end of the leaf spring mounting parts 22R, 22L. If so, the central part 21 and the knuckle spider mounting part may be formed anywhere.

The axle member 20 is acted on simultaneously by a tire (not shown) by a vertical force based on a loaded state and a running state of the vehicle, and a vertical force and a longitudinal force based on a braking state. In particular, the leaf spring mounting portions 22L and 22L
The center portion 21 between the axle member 20 and the center portion 21 is most susceptible to the largest load during loading and braking.
Since 1 is located at the lowest position in the vehicle, it is also susceptible to impact loads from the road surface. Therefore, a bending moment and a torsional moment based on those forces act on the central portion 21. The central portion 21 has a left side portion (front portion) 21a and a lower side portion (lower portion) 21b by a vertical force and a longitudinal force.
Generates a tensile stress, and a right side (rear) 21c and an upper side (upper) 21d generate a compressive stress. Since cast iron, which is a brittle material, has a relation of allowable tensile stress << allowable compressive stress, it is necessary to relax the stress in a portion receiving the tensile stress.

Therefore, in this embodiment, the central portion 2
1, the front part 21a and the lower part 21b which receive the tensile stress are formed to have a large thickness, and the rear part 2 which receives the compressive stress.
The thickness of 1c and the upper part 21d is made thin. Thereby, the centroid of the cross section of the central portion 21 (when the cross-sectional areas are collected at a certain point so that the value of the moment of inertia of a certain surface does not change, the point is called the centroid) G is shown in FIG. ), It is located below the vertical center line (XX line) and to the left (front) of the right and left center line (Y-Y line) of the center section, before it receives tensile stress. It will approach the part 21a side and the lower part 21b side.

Here, as is apparent from the following mathematical formula 1, the normal stress σ at an arbitrary point in the cross section is proportional to a distance e from a neutral axis (this neutral axis passes through the centroid of the cross section). Therefore, the closer the position of the centroid G of the cross section of the central portion 21 to the front portion 21a and the lower portion 21b that receives the tensile stress, or the larger the section modulus Z becomes, the more the position of the centroid G becomes. The vertical stress (tensile stress) σ at an arbitrary point in the cross section of the portion 21a and the lower portion 21b is reduced.

[0021]

Σ = Me / I = M / Z In the above equation 1, M represents a bending moment;
I represents the moment of inertia about the neutral axis, and Z represents the section modulus.

On the other hand, when the position of the centroid G of the cross section of the central portion 21 is closer to the front portion 21a and the lower portion 21b that receive the tensile stress, the rear portion 21c and the upper portion 21d that receive the compressive stress.
Is further away from the centroid G, the compressive stress applied to the rear portion 21c and the upper portion 21d increases. However, as described above, cast iron, which is a brittle material, has a relation of allowable tensile stress << allowable compressive stress. Therefore, relaxing the tensile stress makes it possible to reduce the cross-sectional size and reduce the weight.

As described above, in the present embodiment, the degree of freedom of the sectional shape of the central portion 21 is greatly improved as compared with forging, and a large sectional modulus can be obtained by using a sand core. Thereby, in the case of an axle having the same strength as that of forging, it is possible to reduce the cost and to reduce the weight. In addition, since a large section modulus can be obtained by casting using a sand core, an axle having an ideal cross-sectional shape can be obtained.

In addition, since casting does not require large-scale manufacturing equipment as compared with forging, it is suitable for small-lot production of many kinds, and axles for each vehicle type can be manufactured at low cost. Become. Further, even if the axle has the same strength as that of forging, various cross-sectional shapes can be obtained, so that the degree of freedom for each vehicle type and the degree of design can be greatly improved.

In the above-described embodiment, an example has been described in which the axle suspension device of the present invention is applied to the front rigid axle suspension of an FR vehicle. However, the axle suspension device of the present invention is applied to the rear vehicle of an FR vehicle. (Drive wheel side) It can also be applied to a rigid axle suspension. It is also apparent that the axle suspension device of the present invention can be applied to a front rigid axle suspension or a rear rigid axle suspension of an FF vehicle.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entire configuration of a non-drive wheel side of an axle suspension device of the present invention.

2 shows the structure of the axle member of FIG. 1, FIG. 2 (a) shows a top view, and FIG. 2 (b) shows a side view.

3 shows a cross-sectional view, FIG. 3 (a) showing an AA cross section of FIG. 2, and FIG. 3 (b) showing a BB cross section of FIG.

FIG. 4 is a view showing a template.

FIG. 5 is a view showing a conventional mold.

[Explanation of symbols]

10L, 10R: wheel support, 20: axle member, 21:
Central part, 21x ... Partition part, 22R ... Leaf spring attachment part, 22x, 22y, 22z ... Partition part, 23R ...
Knuckle spider mounting part (end), 23x ... parting part,
G: centroid, 30L, 30R: leaf spring, 40
L, 40R: shock absorber, 50: mold, 51:
Lower mold, 52 ... Upper mold, 53-57 ... Parting surface (cut surface)

Continued on the front page (72) Inventor Junichi Miyagi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Hiroshi Matsuura 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Invention Person: Nishi Ishikawa 3-1-1, Tomikawa-cho, Nakagawa-ku, Nagoya-shi Inside Chuo Kane Kogyo Co., Ltd.

Claims (2)

[Claims] 1. An axle suspension device comprising an axle member extending in a vehicle width direction, connecting left and right wheel supports, and suspending a vehicle body, wherein the axle member is formed by casting and has an end portion. The axle suspension device according to any one of claims 1 to 3, characterized in that the axle member is formed so as to be curved upward toward the wheel support, and a parting-off portion is formed on upper and lower surfaces of the axle member due to a mold mating surface. 2. The vehicle according to claim 1, wherein the axle member includes a suspension spring mounting portion for arranging a suspension spring on the upper and lower surfaces, and the parting-off portion is provided on upper and lower surfaces of the axle member other than the suspension spring mounting portion. The axle suspension according to claim 1, characterized in that: