JP6380260B2 - Differential case - Google Patents

Description

  The present invention relates to a differential case constituting a differential device.

  A differential device that absorbs a difference in rotational speed between right and left wheels and enables smooth running is well known. When power transmitted from the engine side is input to the differential device, it is transmitted to the left and right drive shafts via the ring gear, differential case, pinion shaft, pinion gear, and side gear. In addition, there is known one in which a window for communicating the inside and the outside of the differential case is formed. This is the differential case described in Patent Document 1. By forming the window in the differential case, the differential gear accommodated in the differential case can be assembled from the outside.

Japanese Patent Laid-Open No. 9-229163 Japanese Patent Laid-Open No. 11-30315 JP 2008-8460 A

  When the window is formed in the differential case as in Patent Document 1, the differential case is alternately formed with a portion having high rigidity and a portion having low rigidity in the rotation direction when viewed from the axial direction of the drive shaft. Specifically, the portion of the differential case where the window is formed has low rigidity, and the portion where the window is not formed has high rigidity. As a result, when a high load is input from the ring gear, a high load is also applied to the differential case that supports the ring gear, and there is a possibility that a portion having a low rigidity of the differential case may be plastically deformed. Along with this, the ring gear fixed to the differential case is also plastically deformed, and there is a possibility that gear noise is generated between the ring gear and the drive gear meshing therewith.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a structure capable of suppressing plastic deformation of the differential case even when a high load is input in the differential case formed with a window. There is to do.

The gist of the first invention is (a) a differential case having a gear housing portion that is formed with a window that communicates the inside and the outside and rotates about an axis, and (b) the window A beam member that connects one end side and the other end side of the edge of the frame in a direction parallel to the axis, and (c) both ends of the beam member are connected to the edge of the window by welding, d) The dimension of the beam member in the rotation direction of the gear housing portion is formed so as to increase from the middle in the longitudinal direction of the beam member toward both ends in the longitudinal direction when viewed from the outer peripheral side of the gear housing portion, (E) The end face of the beam member in the rotation direction of the gear housing portion is connected to the gear housing portion, and the side of the beam member becomes longer toward the outer peripheral side of the gear housing portion. It is formed in a taper shape .

  Thus, the rigidity of the site | part in which the window of the gear accommodating part was formed can be improved by providing a beam member in the window formed in the gear accommodating part of a differential case. By the way, since the lubrication of the differential gear accommodated in the gear accommodating portion is performed by guiding the lubricating oil scraped up by the ring gear from the window of the gear accommodating portion into the gear accommodating portion, the beam member is provided on the window. There is a risk of reducing the amount of lubricating oil supplied into the gear housing. On the other hand, the dimension in the rotational direction of the beam member is formed short in the middle of the axial direction, and the end surface in the rotational direction of the beam member is formed in a taper shape. It can be efficiently guided to the differential gear in the gear housing. Thus, ensuring the rigidity of the differential case and securing the amount of lubricating oil in the gear housing portion can both be achieved.

It is sectional drawing of the differential case which is one Example of this invention. It is an external view of the differential case of FIG. It is a figure which shows the shape of the pillar member of FIG. The tooth surface deformation amount (tooth surface deformation amount) of each tooth (outer peripheral tooth) of the ring gear when a high load is input to the ring gear provided in the differential case is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a sectional view of a differential case 10 according to an embodiment of the present invention. The differential case 10 is one of the parts constituting a differential device that absorbs the difference in rotational speed between the left and right wheels and enables smooth running. When the differential case 10 is assembled to a vehicle, the differential case 10 rotates about the axis C1.

  The differential case 10 rotates about an axis C1, and includes a gear accommodating portion 12 in which a differential gear (not shown) is accommodated, a disk-like flange 14 extending radially outward from the outer peripheral surface of the gear accommodating portion 12, and a differential case 10 (or the gear housing portion 12) is provided with a pair of cylindrical bosses 16L and 16R protruding in parallel with the axis C1 from both ends of the gear housing portion 12 in the axial direction (direction parallel to the axis C). Yes. The bosses 16L and 16R are formed around the axis C.

  The gear housing portion 12 is formed of a cylindrical portion 12 a formed in a cylindrical shape and a pair of side walls 12 b and 12 c extending from both ends of the cylindrical portion 12 a toward the inner peripheral side in the axial direction of the differential case 10. A pair of pinion shaft support holes 18a and 18b are formed at positions near the middle of the cylindrical portion 12a in the axial direction of the differential case 10. The pair of pinion shaft support holes 18a and 18b are round holes formed around a common axis C2 orthogonal to the axis C1. Both ends of a pinion shaft (not shown) are fitted into the pair of pinion shaft support holes 18.

  A flange 14 is connected to the outer peripheral end of the tubular portion 12a on the side wall 12b side in the axial direction of the differential case 10. A plurality of bolt holes 20 for connecting a ring gear 19 (refer to FIG. 2) made of a helical gear are formed in the flange 14 in the circumferential direction. A boss 16L is connected to the inner peripheral end of the side wall 12b, and a boss 16R is connected to the inner peripheral end of the side wall 12c. A drive shaft (not shown) is fitted into the through holes 24L and 24R formed in the inner periphery of the bosses 16L and 16R.

  A pair of windows 22 that communicate the inside and the outside of the gear housing portion 12 are formed in the cylindrical portion 12a of the gear housing portion 12 at diagonal positions in the rotational direction. The window 22 is a hole that communicates the inside and the outside of the gear housing portion 12. When viewed from the outer peripheral side of the differential case 10 centered on the axis C, the window 22 is formed in a rectangular shape with corners formed in an arc shape. By forming the window 22, a differential gear composed of a pinion shaft, a pinion gear, etc. (not shown) accommodated in the gear accommodating portion 12 can be assembled.

  FIG. 2 is an external view of the differential case 10 of FIG. In FIG. 2, the ring gear 19 is fastened to the flange 14 of the differential case 10 by bolts 25. As shown in FIG. 2, one end side of the edge of the window 22 in the axial direction of the differential case 10 (gear housing portion 12) is provided at a portion where the window 22 is formed in the circumferential direction of the gear housing portion 12 (tube portion 12 a). A column member 26 that connects the other end side to the other end side is provided. The column member 26 is a flat plate having a predetermined thickness formed in a longitudinal shape, and both ends in the longitudinal direction are connected to the edge of the window 22 by welding. The column member 26 is welded after the differential gear 10 and the ring gear 19 are assembled to the differential case 10. Further, the column member 26 corresponds to the beam member of the present invention.

  FIG. 3 shows the shape of the column member 26 of FIG. 3A is a view of the column member 26 of FIG. 2 as viewed from the outer peripheral side of the differential case 10, and FIG. 3B is a cross-sectional view taken along line AA of FIG. 3A.

  As shown in FIGS. 2 and 3, the column member 26 is formed in a longitudinal shape, and further, when connected to the differential case 10, a constriction is formed in the middle of the column member 26 in the axial direction of the differential case 10. ing. That is, both ends of the column member 26 in the rotation direction of the differential case 10 are formed in an arc shape on the side where the column member 26 is constricted in the middle in the axial direction of the differential case 10 when viewed from the outer peripheral side of the differential case 10. Accordingly, when viewed from the outer peripheral side of the differential case 10, the dimension of the column member 26 in the rotational direction of the differential case 10 is larger than the axial line of the differential case 10 than the both ends in the axial direction when viewed from the outer peripheral side of the differential case 10. The middle of the direction is shorter.

  Further, as shown in FIG. 3B, the dimension in the direction perpendicular to the longitudinal direction of the column member 26 (the dimension in the rotation direction of the differential case 10) is changed as the thickness of the column member 26 is changed. The end faces 28 on both sides in the direction perpendicular to the longitudinal direction of the column member 26 are tapered. Specifically, the end face 28 of the column member 26 is formed in a curved shape. Then, the end surface 28 of the column member 26 is formed in a taper shape, so that the column member 26 is arranged such that the short side in the direction perpendicular to the longitudinal direction of the column member 26 faces the inner side of the differential case 10. Connected to the differential case 10. Therefore, in a state where the column member 26 is connected to the differential case 10, the end surface 28 of the column member 26 in the rotation direction of the differential case 10 moves toward the outer peripheral side of the differential case 10 (gear housing portion 12). It is formed in a tapered shape that spreads (becomes longer).

  As described above, the column member 26 is connected to the portion where the window 22 of the cylindrical portion 12a of the gear accommodating portion 12 is formed, so that the rigidity of the portion where the window 22 of the cylindrical portion 12a of the gear accommodating portion 12 is formed. Will improve. Therefore, even if a high load is applied to the differential case 10 via the ring gear 19, the differential case 10 (gear housing portion 12) has high rigidity, and therefore, the plastic deformation of the differential case 10 is suppressed. Further, the plastic deformation of the ring gear 19 accompanying the plastic deformation of the differential case 10 is also suppressed, and gear noise generated at the meshing portion between the ring gear 19 and a drive gear (not shown) that meshes with the ring gear 19 is suppressed.

  FIG. 4 shows the deformation amount (tooth surface deformation amount) of the tooth surface of each tooth (outer peripheral tooth) of the ring gear 19 when a high load is input to the ring gear 19 fixed to the differential case. The horizontal axis indicates the number (tooth number) assigned to each tooth of the ring gear 19, and the vertical axis indicates the deformation amount of the tooth surface of the tooth corresponding to the tooth number. FIG. 4A shows the deformation amount of each tooth of the ring gear 19 fixed to the differential case 10 of this embodiment, and FIG. 4B shows the ring gear 19 of the differential case without the column member 26 as a comparison object. The deformation amount of each tooth is shown.

  When the column member 26 is not provided, as shown in FIG. 4 (b), the tooth surface of the ring gear 19 located in the vicinity of the portion where the window 22 is formed has a large amount of deformation, and from the window 22 in the rotational direction. The tooth surface of the ring gear 19 at a distant position has a small amount of deformation, and there is a difference in the amount of deformation of the ring gear 19. This is because the pillar member 26 is not provided in the window 22, so that a difference occurs in the rigidity of the gear housing portion 12. That is, since the rigidity in the vicinity of the window 22 of the gear housing portion 12 is low, the amount of change is large, and the ring gear 19 provided in the vicinity of the window 22 of the gear housing portion 12 is also associated with this. The amount of deformation of the tooth surface increases.

  On the other hand, in the differential case 10 of the present embodiment, since the column member 26 is provided on the window 22, the rigidity in the vicinity of the window 22 of the gear housing portion 12 is increased. In relation to this, even in the ring gear 19 located in the vicinity of the window 22, the deformation amount of the tooth surface is smaller than that in the case where the column member 26 is not provided, and is separated from the window 22 in the rotation direction. Even when compared with the deformation amount of the tooth surface of the ring gear 19 at the position, the difference is small. As described above, since the column member 26 is provided in the window 22, the rigidity of the portion of the gear housing portion 12 where the window 22 is formed is improved, so that the deformation amount of the tooth surface of the ring gear 19 near the window 22 is reduced. Reduced.

  By the way, as a contradiction due to the column member 26 being connected to the window 22, the opening area of the window 26 is reduced as a whole, and the lubricating oil scooped up by the ring gear 19 becomes difficult to be supplied into the gear housing portion 12. On the other hand, since the constriction is formed in the middle in the longitudinal direction of the column member 26, the window 22 has a wide opening area in the middle in the axial direction of the differential case 10 (gear housing portion 12). Here, the differential gear (not shown) assembled in the gear housing portion 12 is also arranged in the vicinity of the middle of the window 22 in the axial direction of the differential case 10, so that the lubricating oil scooped up by the ring gear 19 is differentially Efficiently supplied to the gear.

  Further, since the end surface 28 of the column member 26 is formed in a tapered shape, the lubricating oil scraped up by the ring gear 19 is guided into the gear housing portion 12 along the taper of the end surface 28. As described above, the constriction is formed in the column member 26 and the end surface 28 is formed in a tapered shape, so that the lubricating oil is efficiently supplied to the differential gear in the gear housing portion 12. The decrease of is also suppressed.

  As described above, according to the present embodiment, the column member 26 is provided in the window 22 formed in the gear housing portion 12 of the differential case 10, thereby increasing the rigidity of the portion of the gear housing portion 12 where the window 22 is formed. Can be improved. By the way, the lubrication of the differential gear housed in the gear housing portion 12 is performed by guiding the lubricating oil scraped up by the ring gear 19 from the window 22 of the gear housing portion 12 into the gear housing portion 12. If the column member 26 is provided in the gear 22, there is a possibility that the supply amount of the lubricating oil into the gear housing portion 12 is reduced. On the other hand, since the constriction is formed in the middle of the axial direction of the column member 26 and the end surface 28 in the rotation direction of the column member 26 is formed in a tapered shape, the lubricating oil scraped up by the ring gear 19 is efficiently used. Well, it can be guided to the differential gear in the gear housing portion 12. Thus, ensuring of the rigidity of the differential case 10 and securing of the amount of lubricating oil in the gear housing portion 12 can be achieved at the same time.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the windows 22 and 54 are formed at two places in the rotation direction. However, the number of the windows 22 and 54 is not necessarily limited thereto, and is one or three or more. It doesn't matter.

  In the above-described embodiment, the ring gear 19 is formed of a helical gear. However, the present invention is not necessarily limited to the helical gear, and may be formed of, for example, a hypoid gear.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

10, 50: Differential case 12, 52: Gear housing 22, 54: Window 26, 56: Column member (beam member)
28: End face

Claims (1)

A differential case having a gear housing portion formed with a window communicating between the inside and the outside and rotating around an axis,
A beam member for connecting one end side and the other end side in a direction parallel to the axis of the edge of the window;
The beam member is connected to the edge of the window by welding at both ends in the longitudinal direction,
The dimension of the beam member in the rotation direction of the gear housing portion is formed so as to increase from the middle in the longitudinal direction of the beam member toward both ends in the longitudinal direction as seen from the outer peripheral side of the gear housing portion,
The end surface of the beam member in the rotation direction of the gear housing portion is tapered to the side where the dimension of the beam member becomes longer toward the outer peripheral side of the gear housing portion while being connected to the gear housing portion. The differential case is characterized by being formed in.

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