JP2010143352A - Structure of axle case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce stresses at a welded part of a cover and an interface part between a cover fixing surface and a cover body and restrict its deformation to improve durability when a forward or rearward bonding moment acts against an axle case. <P>SOLUTION: In the axle case structure of a welded sheet assembly structure, a flange-like fixing surface arranged in an annular form along an outer circumference of a cover body composed of a substantial semi-sphere shape of a cover is provided with wide surfaces wider than other locations of fixing surface at right and left two locations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in the structure of an axle case in which the deformation of the cover of the axle case is suppressed to increase the reliability.

An axle case 21 having a sheet metal welding assembly structure as shown in FIG. 7 is a ring-shaped reinforcing material for attaching a gear case to the front of a central opening 24 in which both end portions of upper and lower side plates 22 and 23 are butted against each other. 25 is welded, and a substantially hemispherical cover 30 for sealing the lubricating oil of the gear is welded to the rear.
Since a longitudinal force as a main load is input to such an axle case 21 via a torque rod or the like (not shown), a bending moment is applied to the axle case 21 so that the center portion thereof bends in the longitudinal direction.
Then, the center opening 24 and the cover 30 welded thereto have a long axis in the left-right direction along the axis L of the axle case as shown by the solid line position from the two-dot chain line in FIG. Is deformed so as to approach an elliptical shape with a short axis.
For this reason, at the time of these deformations, the weld root portion between the cover 30 and the upper and lower side plates 22.23 corresponding to the two left and right positions of the elliptical long axis direction, and the substantially hemispherical cover body portion provided on the cover 30 A large tensile stress is generated at the boundary between 30A and the flange-shaped attachment surface 30B, which may cause fatigue cracks or oil leakage.
Also, when the maximum vertical load for the axle case is input, the cover is deformed so as to approach a substantially triangular shape instead of an ellipse, but the same tensile stress acts on the upper part of the cover and the three diagonally lower left and right sides. .
Therefore, in order to relieve these stresses and improve the durability of the same part, the outer periphery of the cover 30 is gradually reduced, and the cover end surface is provided at the boundary between the conventional mounting surface part 30B and the cover main body part 30A. An arrangement in which the outer peripheral end face of the cover is disposed on a curved bent portion has been put into practical use.
However, in the case of the above shape, when a large front-rear input is applied to the axle case 21 after the vertical load, when the central opening 24 serving as the cover mounting portion is deformed into an elliptical shape with the left and right as the major axis, a flange-shaped mounting is performed. A large bending stress is generated in the vicinity of the boundary between the left and right portions of the surface portion 30B and the substantially hemispherical cover body portion 30A, and the bead toes of the welded portion of the cover are located at the bending stress generating portion. There was a possibility that it might fall.
In addition, the present applicant has proposed a method of reducing stress concentration in the weld root portion by adding a weld portion between the back side of the cover and the side plate in addition to the weld portion of the cover mounting surface according to Japanese Patent No. 2685717. However, this is accompanied by an increase in the number of welding steps and is not sufficient for stress relaxation at the boundary between the cover mounting surface and the hemispherical shell.
Japanese Patent No. 2685717

  The present invention was devised in view of the above circumstances, and its main problem is that when a longitudinal bending moment acts on the axle case, the cover welded portion, the cover mounting surface portion, and the boundary portion of the cover main body portion It is an object of the present invention to provide an axle case structure that reduces stress and improves durability.

In order to solve the above problem, the invention of claim 1
Upper and lower side plates each having a groove-shaped cross section and having a longitudinal central portion swelled toward the respective web surfaces to form a central opening, and ring-shaped reinforcing plates and substantially hemispheres respectively fixed to the front and rear edges of the central opening In the structure of the axle case of a sheet metal welding assembly structure composed of a shell-like cover,
The flange-shaped mounting surface provided in an annular shape along the outer periphery of the cover body portion having a substantially hemispherical shell shape is provided with a wide surface portion that is wider at the left and right portions than at other portions of the mounting surface. It is characterized by that.
In the invention of claim 2,
The wide surface portion is formed such that left and right peripheral side walls of the cover body portion are recessed inwardly in a planar shape or a curved surface shape, and is formed substantially perpendicular to the mounting surface.
Furthermore, in the invention of claim 3,
The wide surface portion is formed by projecting the left and right surfaces of the flange-shaped mounting surface outward.

In the present invention, when the center opening of the axle case is deformed to be close to an elliptical shape due to the longitudinal bending moment that is the main load acting on the axle case, the cover welded portion and the flange-like mounting surface of the cover are substantially omitted. Widely expanding the left and right parts of the mounting surface, where the high tensile stress occurs, at the boundary with the hemispherical shell body, it is welded around the central opening, and the elliptical center opening Since it becomes easy to follow shaping, the high stress of the tension | tensile_strength generate | occur | produced in the boundary part of the cover welding part and cover attachment surface and hemispherical part accompanying a deformation | transformation can be relieved.
Therefore, unlike the conventional measures for improving the strength of the same part, it is not necessary to increase the thickness of the cover or add welding from the back side of the cover, and the cover can be obtained without increasing the weight and cost of the axle case. The durability of the welded part and the vicinity thereof can be improved.

According to the present invention, wide surface portions are provided on the left and right sides of the mounting surface portion of the cover, so that the high stress is relieved even when a longitudinal bending moment acts on the axle case, and the durability is improved.
Hereinafter, preferred embodiments of the structure of an axle case according to the present invention will be described with reference to the drawings.

As in the prior art, the axle case 1 is welded with the end portions of the upper and lower side plates 2 and 3 butting each other, the ring-shaped reinforcing material 5 is welded in front of the central opening 4, and the rear side of the present invention. A substantially hemispherical shell-shaped cover 10 is welded (see FIG. 6).
As shown in FIG. 1, the cover 10 includes a cover body portion 10A having a substantially hemispherical shape provided in the center, and a flange-shaped mounting surface portion 10B provided along the outer periphery of the cover body portion 10A. Yes.

And the attachment surface part 10B of the cover 10 forms the radial width of two radial directions along the axis L of the axle case 1 in a pair of wide surface parts 14 that are relatively wider than other parts. .
In the present embodiment, as shown in FIG. 1, a range (α) of approximately 30 degrees and a total of approximately 60 degrees with respect to the axis L is set in the wide surface portion 14.
In this invention, the range of the wide surface part 14 is not limited to the said numerical value.

  As the wide surface portion 14, for example, (1) a configuration in which a substantially hemispherical outer peripheral wall of the cover main body portion 10A is recessed in the center direction with respect to the outer periphery of the mounting surface portion 10B, and the width of the mounting surface portion 10B is increased. A configuration in which the width of the flange-like mounting surface portion 10B is extended outward with respect to the outer peripheral wall of the cover main body portion 10A. (3) The outer peripheral wall of the cover main body portion 10A is recessed in the center direction and the width of the mounting surface portion 10B is outward. There is a configuration that spreads out.

In the cover 10 of FIGS. 1 and 2, an example is shown in which the wide surface portion 14 is formed by denting the outer peripheral wall of the cover main body portion 10 </ b> A toward the center.
In the illustrated example, the outer peripheral wall of the cover main body 10A that is curved is a surface H that has a substantially vertical cross-section with respect to the mounting surface 10B in a range of approximately 60 degrees on both the left and right sides with respect to the axis L that extends to the left and right (see FIG. In the example shown, the flat surface was formed and recessed to form a pair of wide surface portions 14 on the mounting surface portion 10B.

  As a result, when a bending moment is applied to the axle case 1 so that the central portion of the axle case 1 bends backward as described above, the outer periphery of the central opening 4 and the cover 10 of the axle case 1 is as shown in FIG. In addition, although it tries to be deformed into a substantially elliptical shape that extends in the left-right direction to become a major axis and contracts in the up-down direction to become a minor axis, the wide surface portion 14 is formed on the left and right of the corresponding mounting surface portion 10B. As shown in FIG. 5, the deformation resistance in the left-right direction (dr direction) increases, the amount of protrusion deformation in the left-right direction of these portions decreases, and the protrusion range is diffused in the circumferential direction.

  Further, as the outer periphery of the cover 10 is deformed into an approximately elliptical shape, the wide surface portion 14 is deformed in a direction (dx direction) in which the outer periphery of the cover 10 is separated from the side plates 2 and 3, and the welded portion 6 of the cover 10 is interposed. The cover mounting surface 4 ′ at the periphery of the central opening 4 of the side plates 2 and 3 is pulled up toward the cover 10, but the mounting surface portion 10 </ b> B in the same portion is enlarged as the wide surface portion 14. The rigidity of the cover main body portion 10A in the vertical direction with respect to the pressure decreases, and the force for pulling the side plates 2 and 3 toward the cover 10 decreases.

  Thus, by forming the wide surface part 14 which expands a welding surface and the surface H perpendicular | vertical to this wide surface part 14 in the outer peripheral wall surface of 10 A of cover main bodies in two right and left places of the attachment surface part 10B of the cover 10, it is an axle. High tensile stress at the boundary between the welded portion 6 of the cover 10 and the cover main body portion 10A and the mounting surface portion 10B when a bending moment that causes the central portion of the case 1 to bend backward can be relaxed. The durability of the part can be improved.

The cover 10 shown in FIG. 4 is a surface whose cross section is perpendicular to the mounting surface portion 10B within a range of approximately 60 degrees on the left and right sides of the curved outer peripheral wall of the cover main body portion 10A with respect to the axis L extending in the left and right directions. A pair of wide surface portions 14 are formed on the left and right of the mounting surface portion 10B by being recessed into a curved surface (cylindrical shape) having a curvature larger than the circular radius of the back surface of the cover body portion 10A so as to be H (see FIG. 2).
Also in this case, the wide surface portion 14 can achieve the same operations and effects as the first embodiment.

  In this invention, instead of the configuration of the vertical surface H described above, the outer peripheral wall of the cover main body portion 10A is recessed so as to have a curved surface (spherical shape) having a curvature larger than the radius of the hemisphere of the cover main body portion 10A. You may do it (not shown).

  In the cover 10 shown in FIG. 5, the outer peripheral wall of the cover main body 10 </ b> A has a substantially hemispherical shell shape as it is without being recessed as in the conventional case, and flanges are formed in a range of approximately 60 degrees on both the left and right sides with respect to the axis L. The mounting surface portion 10B is formed so as to protrude outward, and a pair of wide surface portions 14 are provided on the mounting surface portion 10B.

  Also in this case, since the left and right portions of the mounting surface portion 10B serving as the outer periphery of the cover are widened and the pair of wide surface portions 14 are formed on the cover mounting surface portion 10B, the outer peripheral wall of the cover main body portion 10A is perpendicular to the mounting surface portion 10B. When the cover 10 is deformed so as to be closer to an ellipse, the force of pulling the side plates 2 and 3 toward the cover 10 is relaxed, and the welded portion 6 of the cover, the cover main body portion 10A, and the mounting surface portion 10B There is an effect of reducing high stress generated in the boundary portion.

In this structure, the shape of the cover is the same as that of the conventional structure, and a conventional mold can be used, and interference with a reduction gear or the like built in the cover does not become a problem.
Furthermore, even if the shape of cutting the outer periphery of the cover is increased during manufacturing, it does not increase over the entire periphery of the cover, so that scrap after cutting is reduced and there is no need to increase the material.

  In the above embodiment, the outer periphery of the mounting surface portion 10B is not changed and the outer periphery of the cover main body portion 10A is recessed, or the outer periphery of the cover main body portion 10A is not changed and the outer periphery of the mounting surface portion 10B is expanded outward. However, it is good also as a structure which dents the outer periphery of 10 A of cover main bodies, and extends the outer periphery of the attachment surface part 10B outwardly combining both. In that case, the amount of deformation of each is small.

Further, in the present invention, it is only necessary that the wide surface portions are formed at least at the two left and right portions, and the wide surface portions may be formed at other portions.
For example, as in Japanese Patent Application No. 2007-167035, a wide surface portion is formed in one upper portion of the cover or two diagonally lower left and right sides, or a wide surface portion in which the two wide diagonal surfaces and the left and right wide surface portions are continuous. It may be the case.
In addition, it goes without saying that various design changes can be made without departing from the scope of the present invention.

It is a figure which shows the cover of Example 1, Comprising: (a) And (c) is a rear view, (b) is a perspective view. It is a fragmentary sectional view of the outer peripheral wall and wide surface part of the cover main body of Examples 1 and 2. It is sectional drawing explaining the deformation | transformation of a cover outer peripheral part. It is a figure which shows the cover of Example 2, Comprising: (a) And (c) is a rear view, (b) is a perspective view. It is a figure which shows the cover of Example 3, Comprising: (a) is a rear view, (b) is a perspective view. It is a perspective view which shows the decomposition | disassembly state of the axle case made from a sheet metal of Example 1. FIG. It is a perspective view which shows the decomposition | disassembly state of the conventional sheet metal axle case. It is a rear view which shows the deformation | transformation of the cover by a front-back bending moment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axle case 2, 3 Up-and-down side board 4 Center opening part 5 Reinforcement material 6 Welding part 10 Cover 10A Cover main-body part 10B Attachment surface part 11 Upper position 12, 13 Left-right diagonally downward position 14 Wide surface part 16 Adhering surface part 21 Axle case 22, 23 Up-and-down Side plate 24 Central opening 25 Reinforcing material 30 Cover 30A Cover body 30B Mounting surface

Claims (3)

Upper and lower side plates each having a groove-shaped cross section and having a longitudinal central portion swelled toward the respective web surfaces to form a central opening, and ring-shaped reinforcing plates and substantially hemispheres respectively fixed to the front and rear edges of the central opening In the structure of the axle case of a sheet metal welding assembly structure composed of a shell-like cover,
The flange-shaped mounting surface provided in an annular shape along the outer periphery of the cover body portion having a substantially hemispherical shell shape is provided with a wide surface portion that is wider at the left and right portions than at other portions of the mounting surface. A structure of an axle case characterized by that.   2. The wide surface portion is formed such that left and right peripheral side walls of the cover main body portion are recessed inwardly in a planar shape or a curved surface shape, and is formed substantially perpendicular to the mounting surface. The structure of the axle case described in 1.   The axle case structure according to claim 1, wherein the wide surface portion is formed by projecting left and right surfaces of the flange-shaped mounting surface outward.

Images