JP2000246452A - Welded part shape and welding method of motor case - Google Patents

Abstract

(57) [Problem] To provide a motor case welded portion shape and a welding method capable of reducing the thickness and weight of a motor case, reducing the internal finishing processing allowance, and reducing the processing cost. SOLUTION: A cylindrical motor case body is provided.
In the shape of the welded portion of the motor case assembled by welding the aluminum alloy extruded shape materials 10 divided into a plurality of pieces in the longitudinal direction, the welded portion 20 of the aluminum material 10 has a fitting shape in the longitudinal direction of the cylindrical shape, Weld 2
Ratio T ₀ / T between the thickness T _{0 of 0} and the substantial thickness T ₁ of the non-welded portion.
It is assumed that ₁ is 1.5 to 2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape and a method for welding a motor case for an automobile used in an electric vehicle. More specifically, the present invention relates to a case shape and a welding method of a case for reducing the weight and processing cost of a motor case for an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, an aluminum alloy has been used as a motor case material for an electric vehicle from the viewpoint of weight reduction and heat dissipation. This is because an aluminum alloy is most suitable as a motor case material as compared with other metal materials. A conventional motor case for an electric vehicle generally uses an aluminum casting that is integrally formed without being assembled.

[0003]

However, it is difficult to reduce the thickness of an aluminum casting because it generally has low strength. Therefore, when applied to a motor case,
There was a problem that it was inevitably thicker as a whole and could not meet the needs for weight reduction. In addition, aluminum castings have insufficient dimensional accuracy of the finished product, so the inner diameter part that houses the motor cannot be used as it is, and the finishing processing of the inner diameter part requires a lot of time and man-hours. This was a major factor in raising manufacturing costs.
Therefore, there has been a problem that the motor case can be made thinner and lighter without lowering the strength, and the machining cost can be kept low by reducing the machining allowance for the inner diameter portion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it has been made possible to reduce the thickness and weight of a motor case, further reduce the amount of internal finishing, and reduce the machining cost. It is intended to provide a welding method.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a structure in which an aluminum alloy extruded by dividing a cylindrical motor case body into a plurality of parts in a longitudinal direction. in the weld shape of the motor case assembled by welding form material each other, welds the aluminum material is form fitting shape in the longitudinal direction of the cylindrical shape, substantially of non-welded portion and the thickness T ₀ of the weld the ratio T ₀ / T ₁ between the thickness T ₁ is the weld shape of the motor case is 1.5 to 2.0, further forms a hollow water-cooling jacket section in the non-welded portion of the motor case body portion, Assuming that the inner and outer thicknesses excluding the water cooling passage are t ₁ and t ₂ , respectively, the actual thickness T ₁ of the non-welded portion is the welded shape of the motor case where T ₁ = t ₁ + t _2. further melt bead width W ₀ and the fitting of the weld The ratio W of the uneven dimension W _{1 0} / W ₁
Is greater than 2 and W ₀ is the shape of the welded portion of the motor case formed including W _1, and the material forming the body of the motor case is divided into two parts at equal intervals in the longitudinal direction or 4 parts. It is a division, and the welding order and direction are welding methods of a motor case in which opposite lines are alternately welded in opposite directions,
Molten bead width W of the welded portion comprises an uneven dimension W ₁ of the fitting portion
₀ is formed, and, by a welding method of the motor case of performing welding in the longitudinal direction of the motor case body portion as W ₀ and the ratio W ₀ / W ₁ of W ₁ is larger than 2, problems Is solved.

Hereinafter, the function and effect of the present invention will be described. In the present invention, the weld of the aluminum material is form fitting shape in the longitudinal direction of the cylindrical shape, the ratio T ₀ / T ₁ of the wall thickness T ₀ of the weld virtually thickness T ₁ of the non-welded portion Is 1.5-2.
The reason why the shape of the welded portion of the motor case is 0 is as follows.

[0007] By adopting the fitting structure, it is possible to provide a binding effect between the materials, and to suppress thermal deformation during welding.
In addition, since T ₀ is set to be larger than T ₁ , it is possible to compensate for a decrease in the strength of the welded portion and a decrease in the strength of the welded portion when a welding defect occurs, to maintain the strength of the entire case and to suppress welding heat deformation. Can be. If T ₀ / T ₁ is smaller than 1.5, it is not enough to cover the decrease in the strength of the weld,
If it exceeds 2.0, it is necessary to increase the welding heat input in order to obtain the penetration depth, and on the contrary, the welding heat deformation increases. Therefore, T ₀ / T ₁ is desirably 1.5 to 2.0.

The welding method used in the present invention may be ordinary arc welding, but it is more effective to employ resistance welding, laser welding or electron beam welding in order to further suppress welding deformation.

Further, the welding condition is selected so that the ratio W ₀ / W ₁ of the dimension W _{1 of the} projections and depressions of the fitting portion to the width W ₀ of the welding bead becomes larger than 2, thereby causing a gap between the projections. Welding defects can be eliminated from the welded portion to reduce the probability of remaining internal defects, thereby further suppressing a decrease in the strength of the welded portion. W ₀
If / W ₁ is smaller than 2, welding defects may remain and the strength may be significantly reduced, so that 2 or more is required.

Further, the material forming the body of the motor case is divided into two or four in the longitudinal direction, and the welding sequence and the direction are such that the opposite lines are alternately welded in opposite directions. The reason is that by alternately welding the target parts in the opposite direction, the thermal deformation caused by welding at a certain point can be canceled by the next welding, and finally the torsion and bending deformation become almost zero, and the material This is because assembly can be performed without impairing high precision.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a motor case according to an embodiment of the present invention;

(First Embodiment) FIG. 1 is a view showing a first embodiment of a welding portion shape and a welding method of a motor case according to the present invention, and schematically shows a cross section of a motor case body. FIG. First, the configuration will be described. Cooling fin 30 integrally formed in the longitudinal direction outside the cylindrical case
Extruded aluminum material 10 having
The motor case body is divided and assembled together to form a welded portion 20 in the longitudinal direction of the motor case body.

FIG. 2 (a) shows the detailed shape of the welded portion 20 in FIG. 1. The state before welding is a state where the raw materials are joined together. In FIG. 2A,
Weld thickness T ₀ is 7 mm, the non-welded portion thickness T ₁ is 4 mm, the protrusion of the projections (height) W ₁ is 2mm fitting portion 21, of the case in the center of the section of the welded portion thickness It was formed in the longitudinal direction. Further, a concave portion for fitting is formed in a case portion facing the projection of the fitting portion 21 so that the fitting portion 21 is fitted without any gap.

FIG. 2B is a sectional view showing a state in which welding is performed in the longitudinal direction from the outside of the case in the fitted state of FIG. The weld bead width W ₀ is 5 mm, and includes the protrusion (height) W ₁ of the fitting portion 21.

FIG. 3 is a view showing a method of welding the motor case according to the first embodiment, and shows a welding order and direction when welding a material divided into four parts. The above four weldings are performed in the following order and direction. First, the welding is performed from the back to the front as indicated by the arrow, and then the welding is performed from the front to the back. Next, the welding is performed from the back toward the front. Finally, the welding is performed from the front to the back, and the welding is completed.

(Second Embodiment) FIG. 4 is a diagram showing a second embodiment of the present invention. That is, in the first embodiment, the hollow water-cooled jacket portion 11 is formed in the non-welded portion of the motor case body, and the inner and outer thicknesses t ₁ and t ₂ excluding the water cooling passage are respectively reduced. , T ₁ =
2 mm and t ₂ = 2 mm. In the second embodiment, substantially the thickness T ₁ of the non-weld 4 mm (T ₁
= T ₁ + t ₂ ).

[0017]

As described above in detail, according to the present invention, the structure is such that the aluminum alloy extruded shape material obtained by dividing the cylindrical motor case body into a plurality in the longitudinal direction is welded to each other. In the shape of the welded portion of the motor case assembled by welding, the welded portion of the aluminum material has a fitting shape in the longitudinal direction of the cylindrical shape, and the thickness T of the welded portion is formed.
₀ and the ratio T ₀ / T ₁ of the virtually thickness T ₁ of the non-welded portion is 1.5
~ 2.0, and a hollow water-cooled jacket is formed in the non-welded portion of the motor case body, and the inner and outer wall thicknesses excluding the water-cooling passage are respectively t. ₁ and t ₂ , the actual thickness T ₁ of the non-welded portion is the shape of the welded portion of the motor case where T ₁ = t ₁ + t ₂ , and further, the molten bead width W ₀ of the welded portion and the fitting portion's The ratio W ₀ / W _{1 of the} unevenness dimension W ₁ is larger than 2;
W ₀ is the shape of the welded portion of the motor case formed including W _1, and the material forming the body of the motor case is divided into two or four at equal intervals in the longitudinal direction,
The order and direction of welding is a welding method for a motor case in which opposite lines are alternately welded in opposite directions, and the unevenness dimension W _{1 of the} fitting portion is set.
To form a weld bead width W ₀ of the weld, and
_{Since 0} the ratio W ₀ / W ₁ of W ₁ is a method of welding motor case welding is performed in the longitudinal direction of the motor case body portion so as to be larger than 2, the motor case can thin lightweight, further, the internal An excellent effect that the finishing allowance is small and the processing cost can be reduced can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a welding portion shape and a welding method of a motor case according to the present invention, and is a schematic cross-sectional view of a motor case body.

FIG. 2A is a detailed cross-sectional view of a welded portion (fitting portion) in the first embodiment, and FIG. 2B is a detailed cross-sectional view of the welded portion in a state where a molten bead is formed. .

FIG. 3 is a view for explaining a motor case welding method according to the present invention.

FIG. 4 is a detailed sectional view of a welded portion (fitting portion) according to the second embodiment.

[Explanation of symbols]

10 aluminum extruded shape material 11 water cooling jacket portion 20 welded portion 21 fitting portion 22 molten bead T ₀ weld thickness T ₁ unwelded portion thickness W ₀ weld molten bead width W ₁ fitting portion projection height t ₁ water-cooled Inside wall thickness t ₂ Water cooling outside wall thickness

Claims (5)

[Claims] 1. A motor case body having a cylindrical shape,
In the shape of a welded portion of a motor case which is assembled by welding together extruded aluminum alloy materials divided into a plurality in the longitudinal direction, the welded portion of the aluminum material has a fitting shape in a longitudinal direction of a cylindrical shape, and weld shape of the motor case that the ratio T ₀ / T ₁ of the wall thickness T ₀ parts virtually thickness T ₁ of the non-welded portion is characterized in that 1.5 to 2.0. 2. The shape of the welded portion of the motor case according to claim 1, wherein a hollow water-cooled jacket portion is formed in a non-welded portion of the motor case body portion, and inner and outer wall portions excluding a water cooling passage. When the thicknesses are t ₁ and t ₂ , respectively, the substantial thickness T ₁ of the non-welded portion is T ₁ = t ₁ + t ₂ . 3. A weld shape of the motor case according to claim 1 or 2, molten bead of the weld portion is formed to include a projection of the fitting portion, and the bead width W ₀ of the weld weld shape of the motor case, wherein the ratio W ₀ / W ₁ of the protrusion of the fitting portion (height) W ₁ is greater than 2. 4. The welded shape of the motor case according to claim 1, wherein the material forming the body of the motor case is divided into two or four parts at equal intervals in a longitudinal direction, A welding method for a motor case, wherein opposite welding portions are alternately welded in a reverse order in a welding order and direction. 5. A weld shape of the motor case according to claim 3 or 4 and the welding process, forming a molten bead width W ₀ of the weld including the protruding fitting portion (height) W ₁ And the ratio W ₀ / W ₁ of W ₀ and W ₁
As W ₁ is larger than 2, the welding method of the motor casing, characterized in that welding is performed in the longitudinal direction of the motor case body part.