JP3476573B2 - Aluminum drive shaft - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum drive shaft having a balance weight fixed to correct rotational imbalance.

[0002]

2. Description of the Related Art A drive shaft such as a propeller shaft for transmitting power from an engine to a wheel has a yoke 2 attached to an end of a pipe portion 1 as shown in FIG. It constitutes the transmission system. The drive shaft rotates at high speed when transmitting power from the engine to the wheels. At this time, the centrifugal force generated along with the rotation causes a motion in a direction orthogonal to or intersecting the rotation axis, resulting in vibration or noise, which gives the driver or the passenger a discomfort. As a means for preventing vibration, noise, etc., a balance plate 4 for adjusting the mass distribution around the axis is fixed to the pipe portion 1 and the yoke portion 3 by welding or the like. The balance plate 4 is made of iron, steel or the like having a large mass.

By the way, in order to reduce the weight of vehicles, aluminum, aluminum alloys and the like having a small specific gravity have begun to be used as vehicle bodies and vehicle parts. As a part of this, aluminum drive shafts have been proposed. However, when an iron-based balance plate is attached to an aluminum drive shaft by welding or the like, it is difficult to firmly fix the balance plate due to the difference in weldability due to the material. Therefore, a method of fixing the balance plate to the surface of the drive shaft with an aluminum-based welding metal is adopted. For example, Japanese Patent Publication No. 4-2314
In the publication No. 2, the balance plate 4 is fixed to the pipe portion 1 of the drive shaft with the structure shown in FIG. The balance plate 4 is
It is made of iron having a higher specific gravity than aluminum, and has a hole 5 penetrating in the plate thickness direction in the center. An aluminum-based welding material is used to swell the deposited metal 6 on the surface of the pipe portion 1 looking through the through hole 5 to form the cap portion 7 spread on the surface of the balance plate 4. Thereby, the balance plate 4 is sandwiched between the peripheral surface of the pipe portion 1 and the cap portion 7 and fixed to the peripheral surface of the pipe portion 1.

[0004]

The balance plate 4 is heated by the welding heat input when the deposited metal 6 is formed. When the balance plate 4 is heated to a high temperature, a part of it melts and reacts with the aluminum pipe part 1 and the weld metal 6 to form a hard and brittle Al.
—Fe-based intermetallic compound 9 is produced. In addition, the gas or gas component generated during welding may be caught in the deposited metal 6 to form the blowhole 10. Further, the weld metal 6 and the cap portion 7 made of an aluminum-based welding material have a larger thermal expansion coefficient than the iron-based balance plate 4. Therefore, the shrinkage greatly occurs during the cooling process after welding, and the crack 8 is likely to occur due to the tensile stress generated. In particular, the cap portion 7 is cooled while the balance plate 4 functions as a heat absorber and is attached to the surface of the balance plate 4, so that the cap portion 7 is rapidly cooled while receiving a large binding force. As a result, many cracks are likely to occur inside.

Such welding defects reduce the peel strength of the balance plate 4, and may cause the balance plate 4 to peel due to impact or the like. As a result, the reliability of the drive shaft is reduced, which is a bottleneck in popularizing the drive shaft made of aluminum. The present invention has been devised to solve such a problem, and suppresses the generation of Al-Fe-based intermetallic compounds and the occurrence of cracks by improving the relationship between the balance weight and the deposited metal. It is an object of the present invention to provide a balance weight attached to a pipe portion or a yoke portion with excellent peeling resistance, and to provide a high quality and stable aluminum drive shaft free from vibration and noise.

[0006]

In order to achieve the object, an aluminum drive shaft of the present invention includes an aluminum drive shaft and an iron-based balance weight provided on a pipe portion or a yoke portion of the drive shaft. A welded metal that fills a through hole penetrating the balance weight in the thickness direction and is welded to the surface of the pipe part or the yoke part, and the through hole faces the surface of the pipe part or the yoke part. The side has a small diameter opening, the surface side has a large diameter opening, and a slit extending from the through hole to the outer end surface of the balance weight is formed over the entire thickness direction of the balance weight. It is characterized by closing the opening. Ordinary welding conditions, for example welding current of about 1.6 mm and welding current of 240 A
When welding the balance weight to the drive shaft with, the through hole formed in the balance weight has a small diameter opening with a diameter of 12
It is important to be in the range of -14 mm. Further, it is preferable that the deposited metal has a shape that does not spread on the surface of the balance weight and closes the large-diameter opening.

Specifically, as shown in a plan view (a) and a sectional view (b) of FIG. 3, a balance weight 11 is attached to the pipe portion 1 or the yoke portion of the drive shaft. The balance weight 11 has a rectangular parallelepiped shape having a length L, L ′ = 20 to 40 mm on one side and a thickness T = 2 to 6 mm, and a through hole 12 is formed in the central portion. The small-diameter opening on the side of the pipe 1 has a diameter d ₁ = 12 to ₁₄ mm, and the large-diameter opening on the surface side has a diameter d ₂ of 15 mm or more, forming a tapered inner surface of the through hole 12. Has been done. The surface of the pipe part 1 facing from the through hole 12 is melted and the weld metal 13 is raised by welding. For welding, a welding wire having a diameter of 1.2 to 1.6 mm is usually used, and MIG welding with a welding current of 200 to 280 A is adopted. Under this welding condition, when the arc is directed to the central part of the surface of the pipe part 1 facing from the through hole 12, the arc does not reach the inner wall surface of the through hole 12, and the iron-based balance weight 11 is heated by the arc. Will not be melted by. Therefore, the diffusion reaction between the balance weight 11 and the deposited metal 13 is suppressed, and the Al-Fe-based intermetallic compound is not generated.

Balance weight 11 by arc heating
The diameter d ₁ of the small-diameter opening that does not melt depends on the welding conditions, but according to the experiments of the present inventors, when a welding wire having a diameter of 1.6 mm is used, d ₁ ≧ at a welding current of 240 A.
12 mm, welding current of 220 A required d ₁ ≧ 10 mm, and welding current of 260 A required d ₁ ≧ 14 mm. The balance weight 11 continuously receives radiant heat from the arc during welding. Further, if the straight through hole is formed, the inner wall on the front surface side may catch an arc and be overheated. However, in the present invention, since the through hole 12 is formed by the upwardly widened tapered surface, the peripheral edge on the surface side of the through hole 12 does not pick up an arc. As a result, even on the surface side, F
The diffusion reaction between e and Al is suppressed, and no Al-Fe-based intermetallic compound is generated.

The fixing action of the weld metal 13 will be described with reference to FIG. Weld metal 13 deposited on the pipe part 1
Has a substantially inverted truncated cone shape whose diameter increases from bottom to top following the shape of the through hole 12. Weld metal 13
In the cooling process after welding is completed, as shown in FIG.
It contracts along the axial and radial directions of the inverted truncated cone.
As a result, the deposited metal 13 is, as shown in FIG.
The contraction force in the axial direction exerts a wedge action on the tapered surface of the through hole 12, and the balance weight 11 is fixed to the surface of the pipe portion 1. The stress generated by the contraction in the axial direction is relaxed by the contraction in the radial direction, and is dispersed and received by the tapered surface of the through hole 12. Therefore, stress concentration due to shrinkage is reduced, and the weld metal 13
Does not cause cracks inside. As a result, the wedge effect of the deposited metal 13 is sufficiently exerted, and the balance weight 11 is firmly fixed. In this way, since the fixing force of the balance weight 11 is required for the wedge action of the weld metal 13, a sound weld metal 13 without cracks that tends to occur due to contraction is formed. On the other hand, in the method of fixing the balance weight 11 with the thick cap portion 7 spreading on the surface of the balance weight 11 at the periphery of the through hole 12 as in the known example, the contraction in the axial direction is restrained by the cap portion 7 and is relaxed by the contraction in the radial direction. Is also disturbed. As a result, the occurrence of defects such as cracks in the weld metal 13 after cooling cannot be avoided, and a sufficient fixing force cannot be obtained. However, FIG. 4 (a) and (b)
As shown in FIG. 5, in the thin cap portion 7 ′ to the extent that the welding metal 13 overflows from the through hole 12, the cap portion 7 ′ also deforms as the welding metal 13 contracts. In such a case, the shrinkage of the weld metal 13 is not restrained by the cap portion 7 ′, so that defects such as cracks do not occur inside the weld metal 13.

The formation of cracks due to shrinkage after welding can be completely prevented by forming slits in the balance weight. The slit is effective especially when a thick cap portion is formed. For example, as shown in the plan view (a) and the sectional view (b) in FIG. 5, the slit 15 extending through the wall thickness T of the balance weight 11 is formed in the through hole 12.
From the inner peripheral surface to the outer end surface of the balance weight 11. A part of the balance weight 11 is divided by the slit 15, and expansion and contraction at the time of welding are absorbed by expansion and contraction of the divided portion. As a result, large shrinkage stress does not occur in the weld metal 13, and defects such as cracks are prevented. Further, since the slit 15 is formed over the entire area of the balance weight 11 in the thickness direction, it also functions as an escape path for gas or gas components generated from the start to the end of welding, and defects such as blowholes 14 are welded. It is not generated in the metal 13. The through hole 12 can also be formed as a stepped tapered surface, as shown in the plan view (a) and the sectional view (b) of FIG. 6. The welded metal 13 raised on the stepped portion 16 sandwiches the balance weight 11 between the welded metal 13 and the pipe portion 1 by the force generated by the contraction of the welded metal 13 below the stepped portion 16. Thereby, the balance weight 11 is fixed more reliably. At this time, the contraction force required for sandwiching the balance weight 11 corresponds to about half of the wall thickness T, so that the weld metal 13 itself does not cause defects such as cracks.

[0011]

EXAMPLES Reference Example 1: (FIG. 3) A balance weight 1 is provided on the outer peripheral surface of an aluminum drive shaft.
I installed 1. The balance weight 11 has a diameter d ₁ = 12 mm of a small diameter opening and a diameter d ₂ = 15 of a large diameter opening.
25 mm square with 2 mm through hole 12 and thickness 2 mm
I used a piece of iron. 4 with a diameter of 1.6 mm as a welding material
Using 043 alloy wire, MIG welding was performed for 2 seconds under the welding conditions of 240A and 24V. Formed weld metal 1
Although some blowholes 14 were detected in 3,
No -Fe-based intermetallic compound was detected. No fine cracks were observed in the deposited metal 13 due to shrinkage after cooling. Example 1 (FIG. 5) An iron piece having the same size as that of Reference Example 1 in which a slit 15 having a width of 1 mm from the through hole 12 to the outer end surface was formed was used as the balance weight 11 and welded under the same conditions.
The formed weld metal 13 has a blow hole, Al-F.
Neither e-based intermetallic compound nor fine cracks were detected.

Comparative Example 1: (FIG. 2) The balance weight was attached to the outer peripheral surface of the drive shaft under the same conditions as in Reference Example 1, except that a balance weight having a straight through hole having an inner diameter of 9 mm was used. And
The weld metal 6 was raised to cover a part of the surface of the balance weight with the cap portion 7. A very large amount of intermetallic compound was dispersed in the formed weld metal 6. Also,
Blow holes and small cracks were also frequent. Comparative Example 2: (FIG. 2) Welded metal 6 was the same as Comparative Example 1 except that a balance weight having a straight through hole with an inner diameter of 12 mm was used.
Was formed. In this case, the vicinity of the cap portion 7 (see FIG.
a large amount of intermetallic compounds are dispersed in (see c),
A large number of blowholes were also generated. However, fine cracks were not detected.

Comparative Example 3: (FIG. 2) An iron piece 25 mm square and 3 mm thick with a straight through hole having an inner diameter of 9 mm was used as a balance weight, and the welding time was 2.5 seconds. It was attached to the outer peripheral surface of the drive shaft under the same welding conditions as in Reference Example 1. The deposited metal 6 formed had an extremely large amount of intermetallic compound dispersed therein, and many blowholes and fine cracks were generated. Comparative Example 4: (FIG. 2) A balance weight was attached to the outer peripheral surface of the drive shaft in the same manner as Comparative Example 3 except that a balance weight having a straight through hole having an inner diameter of 12 mm was used. In this case,
A weld metal 6 in which a large amount of intermetallic compound was dispersed was formed in the vicinity of the cap portion 7 (see FIG. 2c). In addition, blowholes frequently occurred, and slight cracks were also detected.

Reference Example 2 An iron piece 25 mm square and 3 mm in wall thickness has a small diameter opening d.
A balance weight having a through hole 12 with a diameter of ₁ = 12 mm and a large diameter opening d ₂ = 18 mm was used. In this case, an inner diameter of 14 mm and an outer diameter of 16 mm are provided on the inner peripheral surface of the through hole 12 at a position 1.5 mm from the outer peripheral surface side of the drive shaft.
The step portion 16 was formed. This balance weight was attached to the outer peripheral surface of the drive shaft under the same welding conditions as in Comparative Example 3. Some blow holes and slight cracks were observed in the deposited metal formed in the through holes 12. Example 2: (Fig. 6) The same balance weight 11 as in Reference Example 2 was used except that the slit 15 having a width of 1 mm was formed, and the balance weight 11 was attached to the outer peripheral surface of the drive shaft. In this case, intermetallic compounds, blowholes,
A good weld metal 13 was formed in which none of the fine cracks was detected.

Reference Example 3: (FIG. 3) An iron piece having a 35 mm square and a wall thickness of 4 mm has a diameter d ₁ of a small diameter opening.
The balance weight 11 in which the through-hole 12 having a large diameter opening d ₂ = 20 mm was formed. With the balance weight 11 applied to the outer peripheral surface of the drive shaft, MIG welding was performed for 3.5 seconds under welding conditions of a current of 240 A and a voltage of 24 V to form the deposited metal 13 inside the through hole 12. In the obtained weld metal 13, some blowholes and fine cracks were detected, but no Al-iron based intermetallic compound was detected. Example 3: (FIG. 5) The same balance weight 11 as in Reference Example 3 was used except that the slit 15 having a width of 3 mm was formed, MIG welding was performed for 4 seconds under the same conditions, and the balance weight 11 was attached to the outer peripheral surface of the drive shaft. In this case, a thin cap portion was produced, but the formed weld metal 1
No intermetallic compounds, blowholes, and microcracks were detected in No. 3.

[0016] Example 4 :( Figure 5) the diameter _{d 1} of the small-diameter opening in the top of the wall thickness 6mm in 35mm angle
= 14 mm, the balance weight 11 in which the through hole 12 having a diameter d ₂ = 22 mm of the large diameter opening and the slit 15 having a width of 4 mm was formed was used. With the balance weight 11 applied to the outer peripheral surface of the drive shaft, MIG welding was performed for 4 seconds under welding conditions of a current of 240 A and a voltage of 24 V.
A deposited metal 13 was formed inside the. Obtained weld metal 1
In No. 3, neither intermetallic compound, blowhole nor fine crack was detected.

Each balance weight attached to the outer peripheral surface of the drive shaft as described above was subjected to a tensile test, and the strength when the balance weight was peeled from the drive shaft was measured. The measurement result is shown in FIG. 7. Comparing those having the balance weights of the same thickness, it is clear from the comparison between Comparative Examples 1 and 2 and Example 1 and the comparison between Comparative Examples 3 and 4 and Example 2 that the tapered surface according to the present invention is obtained. Through hole 1
In the case of using the balance weight 11 formed with No. 2, it was confirmed that the peeling strength was remarkably high and that the balance weight was firmly attached to the drive shaft. Further, the through hole 12 is simply formed by a tapered surface (reference example).
Not only that, but with the balance weight 11 in which the slits 15 are formed together with the tapered surface, no intermetallic compound, blowholes, or microcracks are detected in the weld metal 13, and a stable high peel strength is obtained. Is made. Further, as seen in Examples 3 and 4, even when welding using the balance weight 11 having a large wall thickness for a relatively long period of time, defects that tend to occur in the weld metal 13 are suppressed, and excellent peel strength is obtained. The balance weight 11 could be attached to the outer peripheral surface of the drive shaft.

[0018]

As described above, in the present invention, the through hole formed in the iron-based balance weight is expanded upward, and the slit extending from the through hole to the outer end surface of the balance weight is formed into the balance weight. Is formed over the entire area in the thickness direction. Then, the balance weight is attached to the pipe portion or the yoke portion of the drive shaft by filling the through hole with the weld metal. The deposited metal thus formed has a substantially inverted truncated cone shape following the shape of the through hole formed in a widened shape, and fixes the balance weight to the drive shaft with a strong force. Also, since the balance weight has slits formed over the entire thickness direction,
No Al-iron based intermetallic compounds, blowholes, fine cracks, etc. Therefore, the mass distribution of the drive shaft is adjusted with high quality and reliability, and the drive shaft for vehicle without vibration or noise can be obtained.

[Brief description of drawings]

[Figure 1] Drive shaft with balance plate attached

FIG. 2 is a plan view (a), a sectional view (b) and an enlarged sectional view (c) showing a state where a balance plate is attached by a conventional method.

FIG. 3 is a plan view (a) and a sectional view (b) showing a state in which a balance weight is attached in a reference example.

FIG. 4 is a diagram illustrating the action of a weld metal that fixes a balance weight by a wedge action, and a diagram showing a state after attachment when a thin cap portion 7 ′ is generated (b).

FIG. 5 is a plan view (a) and a sectional view (b) showing a state in which a balance weight having a slit is attached according to the present invention.

FIG. 6 is a plan view (a) and a sectional view (b) showing a state in which a balance weight having a step and a slit is attached.

FIG. 7 is a graph showing the influence of the shape of the through hole on the peel strength of the balance weight.

[Explanation of symbols] 7: Thick cap portion 7 ': Thin cap portion 1
1: Balance weight 12: Through hole 13: Weld metal 14: Blow hole 15: Slit 1
6: Step

Front page continued (72) Yutaka Kawada 2400 Kamigo, Ebina City, Kanagawa Prefecture Automotive Parts Industry Co., Ltd. (72) Inventor's comment ▲ Hao 2400 Kamigo, Ebina City, Kanagawa Prefecture Automotive Parts Industry Co., Ltd. (56) References JP-A-57-130775 (JP, A) JP-A-2-84293 (JP, A) Actual Kaihei 4-71842 (JP, U) JP-B-4-23142 (JP, B2) (58) Survey Areas (Int.Cl. ⁷ , DB name) F16F 15/34 B60B 35/12 B23K 9/00

Claims (3)

(57) [Claims] 1. A pipe comprising an aluminum drive shaft, an iron-based balance weight provided on a pipe portion or a yoke portion of the drive shaft, and a through hole penetrating the balance weight in a thickness direction. or a weld metal that is welded to the surface of the yoke portion, the through hole is the pipe portion or side small-diameter opening facing the surface of the yoke portion, the surface side has become a large-diameter opening, yet the through-holes Balance from
The slit extending to the outer end surface of the weight is the balance
An aluminum drive shaft, which is formed over the entire thickness direction of the weight and closes the large-diameter opening with the weld metal. 2. The aluminum drive shaft according to claim 1, wherein a through hole having a diameter of the small diameter opening portion of 12 to 14 mm is formed in the balance weight. 3. The deposited metal according to claim 1 or 2 is balun.
Block the large diameter opening without spreading over the surface of the weight
Aluminum drive shaft are.