JPH09188115A - Manufacture of vehicular composite axle beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a vehicular composite axle beam which has high strength and allos a low manufacturing cost and which is capable of ensuring the sharing of parts and reducing its own weight without lowering the operating performance of a vehicle at the cost of steering angle. SOLUTION: A projecting junction part 36 is formed at a tire-mounting part 32, and at the junction part 36, a circular groove 38 is provided, for example, on the periphery. On the other hand, a recessed part 34 which is shaped so that the projecting junction part 36 is fitted into it, is formed at a junction part 33 of an intermediate part (vehicle supporting part) 31 having a spring mounting seat 37. The tire-mounting part 32 is manufactured by forging a steel material, thereafter conditioning and heat-treating, and machining it. Besides, the intermediate part (vehicle supporting part) 31 is formed by forging an aluminum- or aluminum alloy material, and the recessed part 34 is formed by machining. Then, after the junction part 36 of the tire-mounting part 32 is fitted into the recessed part 34 of the intermediate part (vehicle supporting part) 31, the intermediate part (vehicle supporting part) 31 is finish-forged, and the junction part 33 into which the junction part 36 is fitted, is integrally forged and joined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle beam which is a suspension component for a vehicle such as a truck, and more particularly to 3
The present invention relates to a method of manufacturing a composite axle beam for a vehicle having a split structure.

[0002]

2. Description of the Related Art Axle beams for trucks, particularly front axle beams, are conventionally made of forged carbon steel or alloy steel, and have a steel axle beam of an integral structure.
There is an aluminum alloy axle beam having an integral structure manufactured by forging an aluminum alloy.

FIG. 7 is a plan view showing the structure of a conventional front axle beam, and FIG. 8 is a front view thereof. 7 and 8, the rightmost spindle is not shown.

The axle beam 1 is formed with two spring mounting seats 3 for mounting leaf springs at a ¼ portion from both ends thereof. Then, between the both ends of the axle beam 1 and the two spring mounting seats 3, the kingpin boss portions 2 are respectively provided.
And a spindle 7 for mounting a tire (not shown) is provided between each kingpin boss portion 2 and the end portion of the axle beam 1. As mentioned above, only the leftmost spindle 7 is shown.

The kingpin boss portion 2 is fitted in a U-shaped knuckle 4 provided at the end portion on the spindle 7 side, and a connecting portion 6 at the end portion on the spring mounting seat 3 side is fitted in this way. The knuckle 4 and the connecting part 6 with the kingpin 5
It has a structure in which both are inserted and connected. Therefore, the spindle 7 can rotate around the kingpin 5 with respect to the axle beam main body on the side of the spring mounting seat 3, and by operating the handle, the spindle 7 and the tire change the angle with respect to the vehicle, and the tire moves in the traveling direction. It is facing you. FIG. 10 is a view showing the relationship between the connecting portion 6 on the axle beam body side and the knuckle 4 on the spindle 7 side when the handle is operated, that is, when the vehicle turns. The kingpin 5 is inclined so that the upper end thereof is slightly inward with respect to the vertical direction, thereby forming a kingpin inclination angle.

Further, the main body of the axle beam 1 on the side of the spring mounting seat 3 has a beam shape which is basically flattened in the vertical direction.
As shown in FIG. 9D, the cross section taken along line -E has an I shape having flanges at both upper and lower ends, and in the spring mounting seat 3, the cross section taken along line DD of FIG. 8 is shown in FIG. 9C. As shown, the upper end flange is large and the lower end flange is small.
8 and 9, a convex lens shape is formed as shown by the line CC in FIG. 8, and a cross section taken along the line BB in FIG. 8 is shown in FIG. 9A at the connecting portion 6 of the kingpin boss portion 2. As shown, it is almost square. In this way, the cross-sectional shape of the axle beam main body changes from a flat shape to a square shape in the vertical direction from the central portion toward the side.

The axle beam having such a structure is formed into a shape capable of ensuring strength and rigidity in a required portion. By performing this forming process by forging, the strength and rigidity of the entire material can be ensured. ing.

[0008]

However, the above-mentioned conventional axle beam has the following drawbacks. Recently, weight reduction of vehicles has become an inevitable demand. Under this demand, front axle beams such as trucks are
The use of aluminum alloys instead of the traditional steels has been a challenge. However, if it is attempted to manufacture a front axle beam from an aluminum alloy for the purpose of reducing this weight, the wall thickness will be made thicker than that made of steel in order to make the strength and rigidity equivalent to those made of steel. There is a need.

In particular, since a large load is applied to the kingpin boss portion 2, the insertion hole and the outer peripheral edge of the connection portion are formed around the insertion hole of the kingpin 5 in the connection portion 6 on the axle beam body side. The spacing should be larger than that of steel. That is, as shown in FIG. 10, it is necessary to increase the thickness of the peripheral portion of the kingpin insertion hole in the vehicle front-rear direction and the vehicle left-right direction.

However, if the wall thickness of this portion is increased, the knuckle 4 connected via the kingpin 5 is present in the vicinity of the connecting portion 6, so that the shape of the knuckle 4 is the same as that of steel. Therefore, there are various obstacles in driving or designing the vehicle. In particular, in the vehicle front-rear direction shown in FIG. 10, when the thickness of the peripheral portion of the insertion hole of the connecting portion 6 becomes large, the knuckle 4 interferes with the connecting portion 6, and the allowable value of the rolling angle becomes small, so that the minimum rotation The radius becomes smaller. If so, there is a problem in driving the vehicle.

On the other hand, in the vehicle left-right direction, if the thickness of the peripheral portion of the insertion hole of the connecting portion 6 becomes large, it becomes necessary to move the knuckle 4 and the spindle 7 to the outside, which increases the distance between the left and right tires. This has the drawback of being a constraint in vehicle design.

In order to eliminate these drawbacks, in order to thicken the peripheral portion of the hole of the connecting portion 6, the knuckle must be changed to a shape different from that of conventional steel, and other steel axles are required. Since the knuckle cannot be shared with the vehicle type using the beam, the manufacturing cost increases. In particular, recently, in order to reduce the manufacturing cost, it is inevitable to share parts, and in order to reduce the weight, it must be abandoned to share parts, which is not a practical means to achieve the purpose. I can't say.

The present invention has been made in view of the above problems, and it is possible to secure the sharing of parts, reduce the driving performance of the vehicle at the sacrifice of the turning angle, and reduce the weight. An object of the present invention is to provide a method of manufacturing a composite axle beam for a vehicle, which is capable of being manufactured.

[0014]

A method of manufacturing a composite axle beam for a vehicle according to the present invention comprises a steel tire having kingpin boss portions at both ends of a vehicle support portion made of aluminum or an aluminum alloy having a spring mounting seat. A method of manufacturing a vehicle composite axle beam having a three-part structure in which mounting portions are coupled to each other, wherein one coupling portion of the vehicle support portion and the tire mounting portion is fitted into a recess provided in the other coupling portion. It is characterized in that both joint portions are joined by hot forging to join the vehicle support portion and the tire mounting portion.

Further, it is preferable that a recess is provided in the joint of the vehicle support and the joint of the tire mounting portion is fitted in the recess.

Further, it is preferable to provide unevenness such as parallel grooves extending in the longitudinal direction of the axle beam, circumferential annular grooves, spiral grooves or dents on the surface of the joint portion of the tire mounting portion.

[0017]

In the present invention, the tire mounting portion having the kingpin boss portion that has mechanical movement and is required to have strength and rigidity is made of steel, and the vehicle supporting portion which is sufficient only for the function as the beam is made of aluminum or aluminum alloy. Made. Then, an axle beam is formed by connecting the tire mounting portion and the vehicle supporting portion. Since the axle beam has such a three-part structure, the required strength and rigidity are secured in the portion where strength and rigidity are required, while the portion functioning as a beam occupying most of the longitudinal direction of the axle beam is secured. By reducing the weight, the weight of the entire axle beam can be significantly reduced.

In order to manufacture the axle beam having such advantages, in the method of the present invention, first, the vehicle support portion is hot forged, and then either one of the vehicle support portion and the tire mounting portion is joined. A recess having a shape into which the other coupling portion fits is provided. Next, the other connecting portion is fitted into this recess, the vehicle supporting portion is finish-forged, and both joint portions are integrally hot forged and joined. Then, the joint surfaces of both joints are subjected to plastic deformation, and the newly activated active surface of the joints serves as an interface, and the vehicle support portion made of aluminum and the tire mounting portion made of steel are subjected to hot solid-phase joining. Therefore, when the vehicle composite axle beam is manufactured by the method of the present invention, the weight of the entire vehicle is reduced, and the axle beam having the improved strength of the joint portion can be obtained.

By the way, in the present invention, if the joint portion having the recess is made of steel, the forging temperature of steel is too high for aluminum, so that forging becomes difficult. Further, the aluminum material has a lower hardness than the steel material and is easily deformed. Therefore, in the method of the present invention in which the joint portion having the concave portion is forged toward the other joint portion and joined, the joint portion having the concave portion is an aluminum material, that is, the concave portion is formed in the joint portion of the vehicle support portion. It is preferable to provide and fit the joint portion of the tire mounting portion.

In this case, if unevenness is provided on the surface of the joint portion of the tire mounting portion, aluminum, which is the material of the vehicle supporting part, flows into the concave portion of the unevenness during forging. Therefore, compared with the case where the surface of the joint portion of the tire mounting portion is flat and the joint portion is joined to the vehicle support portion only by solid-phase joining, when the groove or the like is formed in the joint portion, the mechanical joining The effect increases the strength.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view of an axle beam according to an embodiment of the present invention, and FIG. 2 is AA 'in FIG.
It is sectional drawing of a surface. It should be noted that the intermediate portion (vehicle support portion) 31 is shown in substantially half thereof, the tire mounting portion 32 is shown only one of them, and the kingpin boss portion and the spindle portion are not shown.

The tire mounting portion 32 is formed with a convex coupling portion 36, and the coupling portion 36 is provided with, for example, an annular groove 38 in the circumferential direction. On the other hand, the spring mounting seat 3
The joint portion 33 of the intermediate portion (vehicle support portion) 31 having 7 has a concave portion 34 having a shape into which a convex joint portion 36 is fitted.

The tire mounting portion 32 having a kingpin boss portion (not shown) is manufactured, for example, by forging carbon steel S45C, heat-treating it, and machining it. The intermediate portion (vehicle support portion) 31 is, for example, J
It is formed by forging an IS6061 aluminum alloy, and the recess 34 is formed by machining. Then, the joint portion 36 of the tire mounting portion 32 is fitted into the recess 34 of the joint portion 33, and both are joined by hot forging.

In the present embodiment thus constructed, since the axle beam has a three-part structure, the tire mounting portion 32, which is required to have strength and rigidity, has the required strength and rigidity, while the axle is used. By reducing the weight of the intermediate portion (vehicle support portion) 31 that occupies most of the longitudinal direction of the beam, it is possible to significantly reduce the weight of the entire axle beam. Therefore, it is possible to reduce the weight without changing the shape, that is, to secure the sharing of the parts and to keep the turning angle equal to that of the steel integrated type. Further, by arranging the split position between the spring mounting seat 37 and the kingpin boss portion, a portion that occupies most of the weight of the conventional steel integrated axle beam, that is, a portion between the left and right spring mounting seats. Since the weight is reduced by aluminum or aluminum alloy, the weight reduction effect of the entire axle beam is great.

For example, in this embodiment, a weight reduction of 25% can be obtained as compared with the weight of the conventional carbon steel S45C forged integral type axle beam having the same strength and rigidity.

In the method of this embodiment, the tire mounting portion 3
2 of the connecting portion 36 to the intermediate portion (vehicle supporting portion) 31 of the connecting portion 3
After fitting in the concave portion 34 of 3, the intermediate portion (vehicle support portion) 31
Is subjected to hot finish forging, and the joint portion 33 into which the joint portion 36 is fitted is integrally forged and joined. Therefore, according to the method of the present embodiment, the manufacturing cost is low and the high-strength axle beam can be manufactured.

For example, as a method of joining the joint portions 33 and 36, as shown in FIG.
A method of connecting the tire mounting portion and the tire mounting portion with a bolt can be considered.

In this axle beam, an axle beam intermediate portion (vehicle support portion) 11 having a spring mounting seat 17 for fixing and supporting a leaf spring (not shown) has flanges 15 formed at both ends thereof. . Further, the tire mounting portion 12 having a kingpin boss portion (not shown) also has a flange 16 formed at the end portion on the side of the intermediate portion 11. The flanges 15 and 16 are attached to the bolt 13 and the nut 1.
The intermediate portion 11 and the tire mounting portion 12 are connected by being fastened by means of No. 4 and are fixed to each other to be integrally assembled.

Further, as shown in FIG. 10, a method of connecting the intermediate portion (vehicle supporting portion) and the tire mounting portion with a cast doll can be considered.

This is an intermediate portion (vehicle support portion) 21 having a spring mounting seat 27 and a kingpin boss portion (not shown).
And tire mounting portion 22 having a spindle (not shown)
And are joined by a cast toy. That is, the tire mounting portion 22 is manufactured by forging, and the projection 26 is formed on the connecting portion 25 of the tire mounting portion 22. Then, by casting the molten aluminum alloy into a beam shape so as to surround the projection 26,
An intermediate portion (vehicle support portion) 21 having a spring mounting seat 27 is manufactured. The connecting portion 23 of the intermediate portion 21 has a concave portion 24.
The projection 26 is fitted in.

The present embodiment has the following advantages over these joining methods. That is, in the method of this embodiment, as shown in FIG. 9, since no flange is provided in the joint, the weight of the flange does not interfere with the tie rod arm and the knuckle arm arranged around the joint. The amount can be reduced. Further, in this embodiment, since the intermediate portion 31 can be manufactured by forging an aluminum alloy, the strength can be increased by forging, so that the intermediate portion 3 can be manufactured more easily than the one manufactured by casting.
The wall thickness of 1 can be reduced. Therefore, the weight of the axle beam can be further reduced.

By the way, the strength of the joint between the tire mounting portion 32 and the vehicle support portion 31 of the axle beam according to this embodiment is generally proportional to the surface area of the joint portion 36 of the tire mounting portion 32. In order to verify this, a carbon steel S45C member having a convex joint having various surface areas and a JIS6061 aluminum alloy member having a recess having a size fitting to the joint are provided in the method of this embodiment. According to the above, forging joining was performed, and a tensile test was performed on each test piece. However, the workability at the time of forging was 25%, and the convex joint portion was a flat surface without forming irregularities, and only the surface area was changed.

FIG. 5 is a graph showing the evaluation result of the tensile test for each test piece, with the vertical axis representing the maximum tensile load F _B (N) and the horizontal axis representing the surface area A (mm ² ) of the joint. is there. As shown in FIG. 5, when the surface area of the joint is small, the maximum tensile load F _B is also small, and as the surface area of the convex joint increases, the maximum pull-out load increases and the strength of the joint increases. Thus, since the tensile load is proportional to the surface area of the coupling portion, the bonding strength due to forge bond has a tensile load (F _B / A) per unit area of the coupling portion, i.e.,
It can be represented by shear peel strength. Therefore, the shear peel strength is 12 MPa when the forging degree is 25%.

Further, since the strength of the joint portion depends on the cross-sectional area of the joint portion of both members, the surface area and cross-sectional area of the joint portion of the tire mounting portion and the cross-sectional area of the joint portion of the vehicle support portion are appropriately set. As a result, a desired strength can be obtained. Specifically, the surface area of the convex joint portion is A ₁ , the cross sectional area of the joint portion of the vehicle support portion is A ₂ , the cross sectional area of the joint portion of the tire mounting portion is A ₃ , the shear peel strength is S ₁ , the vehicle the yield strength of the material constituting the support portion S _2, when the strength of the material constituting the tire mounting portion and S _3, sets the a _1, a ₂ and a ₃ required to obtain a desired maximum tensile load F can do. That is, A ₁ > F / S ₁ , A ₂ > F / S ₂ and A ₃ > F
It is advisable to set the values of A ₁ , A ₂ and A ₃ so as to satisfy / S ₃ .

In the present embodiment, the tire mounting portion 32 in which the annular groove 38 is formed in the convex joint portion 36 is used, but in addition, joint portions having various shapes as shown in FIG. 6 may be used. It is possible to use the tire mounting part that has. For example, as shown in FIG. 6A, the connecting portion 36 of the tire mounting portion 32 is
6 in which no groove or the like is formed, as shown in FIG. 6B, a spiral groove 38a is formed,
As shown in FIG. 6 (c), there are those in which a parallel groove 38b is formed in the longitudinal direction of the axle beam, and those in which a coupling portion 36 is provided with a recess 39 as shown in FIG. 6 (d).

As described above, when the groove or the recess is formed in the convex joint, the bonding strength is improved as compared with the case where the joint is formed by the flat joint having no groove or the recess. To do. This is because the joining area is increased by forming the groove or the recess, and in addition, the aluminum and the aluminum are introduced into the groove or the recess to mechanically bond the two.

In order to verify this, carbon steel S45 having a convex joint with an annular groove as shown in FIG.
A C-made member and a JIS6061 aluminum alloy-made member provided with a recess having a size that fits in the joint are used to forge-join according to the method of this example to produce a test piece, and the test piece is stretched. The test was conducted. However, the conditions other than the surface shape of the convex joint were the same as those of the test piece prepared in the tensile test shown in FIG.
As a result, when the surface area of the convex joint portion was set to 830 mm ² , the maximum tensile load was 29300 N, and compared with the case of joining using the grooveless convex joint portion shown in FIG. With the same surface area, it was possible to obtain a maximum drawing load of about 3 times. Therefore, if a groove or the like is formed on the surface of the convex joint, it is possible to reduce the surface area of the convex joint required to obtain a desired maximum tensile load.

[0039]

As described above in detail, according to the method of the present invention, either one of the vehicle supporting portion made of aluminum or aluminum alloy and the tire mounting portion made of steel is provided at the other connecting portion. Since it fits in the recessed part and both joints are joined by hot forging, sharing of parts can be ensured and at the same time, it is lightweight without sacrificing the turning angle and reducing the driving performance of the vehicle. It is possible to manufacture a high-strength vehicle composite axle beam at a low manufacturing cost. Further, when the concave portion is provided in the joint portion of the vehicle support portion and the unevenness is provided on the surface of the joint portion of the tire mounting portion, the joint strength can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an axle beam according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line A-A ′ in FIG.

FIG. 3 is a schematic diagram showing an axle beam in which an intermediate portion (vehicle support portion) and a tire mounting portion are connected by bolts.

FIG. 4 is a schematic diagram showing an axle beam in which an intermediate portion (vehicle support portion) and a tire mounting portion are joined by a cast case.

FIG. 5 is a graph showing the evaluation results of the tensile test for each test piece, with the vertical axis representing the maximum tensile load F _B (N) and the horizontal axis representing the surface area A (mm ² ) of the joint.

FIG. 6 is a side view showing an example of the shape of the joint portion of the tire mounting portion.

FIG. 7 is a plan view showing a structure of a conventional front axle beam.

FIG. 8 is a front view showing a structure of a conventional front axle beam.

9 is a cross-sectional view taken along the line EE of FIG.

FIG. 10 is a connecting portion 6 on the axle beam main body side when the vehicle turns.
It is a figure which shows the relationship between the knuckle 4 by the side of a spindle 7, and.

[Explanation of symbols]

 1: Axle beam 2: King pin boss part 3: Spring mounting seat 4: Knuckle 5: King pin 6: Connection part 7: Spindle 11, 21, 31: Intermediate part 12, 22, 32: Tire support part 13: Bolt 14: Nut 15, 16: Flange 23, 25: Connection part 24, 34: Recessed part 26: Protrusion 33, 36; Coupling part 38; Groove

Claims (4)

[Claims] 1. A method of manufacturing a vehicle composite axle beam having a three-part structure in which a steel tire mounting portion having a kingpin boss portion is coupled to both ends of a vehicle supporting portion made of aluminum or an aluminum alloy having a spring mounting seat. In the above, the connecting portion of any one of the vehicle supporting portion and the tire mounting portion is fitted into a recess provided in the other connecting portion, and both connecting portions are joined by hot forging to provide the vehicle supporting portion. A method for manufacturing an axle beam, characterized in that the portion and the tire mounting portion are joined together. 2. A recess is provided in the coupling portion of the vehicle support portion,
The method for manufacturing a vehicle composite axle beam according to claim 1, wherein a joint portion of a tire mounting portion is fitted into the recess. 3. The method for manufacturing a composite axle beam for a vehicle according to claim 2, wherein unevenness is provided on a surface of the joint portion of the tire mounting portion. 4. The method of manufacturing a composite axle beam for a vehicle according to claim 3, wherein the unevenness is a parallel groove extending in a longitudinal direction of the axle beam, a circular groove in a circumferential direction, a spiral groove, or a recess. .