JP2011117540A - Vehicle differential gear device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle differential gear device capable of preventing a welding depth from being further deepened while continuously applying penetration welding to a flange part and a ring gear in a circumferential direction. <P>SOLUTION: In a location adjacent to an inner peripheral side of a pair of contact surfaces 22a and 24a to be welded, an outer peripheral edge is located at a radial location a corresponding to a lower limit value A of a necessary welding depth and an inner peripheral edge is located at a radial location b corresponding to an upper limit value B of the necessary welding depth. A first annular gap 30 is provided where the gap in an axial direction C is set to equal to or less than a first size D1 filled with the welding. A second annular gap 32 is provided at a position adjacent to an inner peripheral side of the first annular gap 30, where the gap in the axial direction C is set to larger than the first size D1, which is not filled with the welding. The welding is applied so that a minimum value of a variation range of a penetration depth X1 of a weld bead 28 is greater than the lower limit value A of the necessary welding depth. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a differential gear device for a vehicle, and in particular, the welding depth in the radial direction between the flange portion and the ring gear becomes deeper than necessary while continuously welding the flange portion and the ring gear in the circumferential direction. The present invention relates to a technique for suppressing the problem.

  A differential case having a pair of side gears opposed to each other and a pinion meshing with them in a state where the pinion is rotatably supported and having an annular flange portion integrally projected from the cylindrical outer peripheral surface to the outer peripheral side; An annular ring gear welded between one side surface in the axial direction of the flange portion and one end surface brought into contact with the one side surface, and the power input to the ring gear is transmitted to the pair of side gears. 2. Description of the Related Art A vehicle differential gear device that transmits a rotation difference to a rotating member connected to the pair of side gears while allowing a rotation difference is known. For example, it is described in Patent Document 1.

  The differential case of Patent Document 1 includes an annular protrusion that protrudes toward one side of the flange portion and contacts the ring gear at one side of the flange portion when the differential case and the ring gear are combined before being welded to each other. (Web) is provided. Thus, annular gaps (first gap and second gap) are formed between the flange portion of the differential case and the ring gear, which are combined with each other, on the outer peripheral side and the inner peripheral side with the annular protrusion interposed therebetween. Is done. The differential case and the ring gear combined with each other are welded to each other by, for example, a laser beam while an additive material containing, for example, nickel is supplied into a gap on the outer peripheral side of the annular protrusion. In the welding, the surplus additive material flows into the gap on the inner peripheral side of the annular protrusion, so that a local bulge is not formed on the weld bead, and a weld bead having a smooth outer peripheral surface is obtained.

EP1719572A2

  By the way, in the above-mentioned conventional differential gear device for a vehicle, since the penetration depth of the weld bead formed by welding the flange portion and the ring gear becomes shallow, the flange portion and the ring gear penetrate in the radial direction and are welded. In some cases, the abutting portion between one side surface of the flange portion and one end surface of the ring gear may remain at a position adjacent to the inner peripheral side of the weld bead. In such a case, when the weld bead is solidified and shrinks after welding, the butt portion becomes a resistance to the shrinkage, so that a tensile residual stress is generated in the weld bead and the durability of the weld bead is lowered. There was a possibility. On the other hand, it is conceivable that the penetration depth of the weld bead is sufficiently deep so that the flange portion and the ring gear are continuously welded in the radial direction in the circumferential direction. However, if the welding depth in the radial direction between the flange portion and the ring gear, that is, the weld leg length becomes excessively deeper than necessary by increasing the penetration depth of the weld bead, the shrinkage force of the weld bead after welding increases. Since the distortion of the ring gear and the flange portion increases, there is a possibility that the ring gear is hard, that is, the ring gear shaft center is inclined with respect to the differential case shaft center.

  The present invention has been made against the background of the above circumstances. The object of the present invention is to provide a welding depth in the radial direction between the flange portion and the ring gear while continuously welding the flange portion and the ring gear in the circumferential direction. An object of the present invention is to provide a vehicle differential gear device capable of suppressing the depth of the vehicle from becoming deeper than necessary.

  To achieve this object, the gist of the invention according to claim 1 is that (a) a pair of opposite side gears and a pinion meshing with each other are accommodated in a state in which the pinion is rotatably supported and a cylinder. Welding between a differential case having an annular flange portion projecting integrally from the outer peripheral surface to the outer peripheral side, and one end surface in contact with one side surface in the axial direction of the flange portion An annular ring gear configured to transmit a power input to the ring gear to a rotating member connected to the pair of side gears while allowing a rotational difference between the pair of side gears. And (b) one side surface of the flange portion and one end surface of the ring gear correspond to a lower limit value of a necessary welding depth predetermined in a radial direction in the mutual welding. An inner peripheral edge is positioned at a directional position, and a pair of contact surfaces that are brought into contact with each other before welding is formed, and (c) adjacent to the inner peripheral side of the contacted pair of contact surfaces The inner peripheral edge is positioned at a radial position corresponding to an upper limit value of a required welding depth predetermined in the radial direction in the welding, and the axial distance between the flange portion and the ring gear is Is provided with a first annular gap set to be equal to or smaller than the first dimension filled by the welding, and (d) at a position adjacent to the inner peripheral side of the first annular gap, the flange portion and the ring gear There is a second annular gap in which an interval in the axial direction is set larger than the first dimension which is not filled by the welding.

  The gist of the invention according to claim 2 is that, in the invention according to claim 1, welding of the flange portion and the ring gear reaches the first annular gap from the outer peripheral side of the flange portion and the ring gear. That is, a welding bead having a depth to be formed is continuously formed in the circumferential direction.

  The gist of the invention according to claim 3 is that, in the invention according to claim 1 or 2, the first dimension is a thickness in an axial direction of an inner peripheral end of a weld bead formed by the welding. This is because it is set smaller than the dimension.

  According to the differential gear device for a vehicle according to the first aspect of the present invention, adjacent to the inner peripheral side of the pair of contact surfaces in which the inner peripheral edge is positioned at the radial position corresponding to the lower limit value of the required welding depth. In the position, the inner peripheral edge is positioned at a radial position corresponding to the upper limit value of the required welding depth, and the axial distance between the flange portion and the ring gear is set to be equal to or less than the first dimension filled by the mutual welding. The first annular gap is provided, and the axial distance between the flange portion and the ring gear is not filled by the welding at a position adjacent to the inner circumferential side of the first annular gap. Since the second annular gap set larger than the dimension is provided, the outer peripheral edge of the first annular gap is positioned at the radial position corresponding to the lower limit value of the required welding depth. The penetration depth of the weld bead Through-welding is ensured if welding is performed so as to exceed the lower limit of the depth, and even if the penetration depth of the weld bead exceeds the upper limit of the required welding depth, the flange portion and the ring gear The weld depth in the radial direction, that is, the weld leg length does not exceed the upper limit of the required weld depth, so that the weld depth is more than necessary even though the flange portion and the ring gear are continuously welded in the circumferential direction. It is possible to suppress deepening.

  According to the differential gear device for a vehicle of the invention according to claim 2, the welding of the flange portion and the ring gear has a depth that reaches the first annular gap from the outer peripheral side of the flange portion and the ring gear. Since the weld bead is continuously formed in the circumferential direction, the ring gear and the flange portion are welded so as to penetrate in the radial direction continuously in the circumferential direction. Therefore, for example, when the flange portion and the ring gear are not continuously welded in the circumferential direction, the abutting portion between one side surface of the flange portion and one end surface of the ring gear is located at a position adjacent to the inner peripheral side of the weld bead. If the weld bead solidifies and shrinks after welding, tensile residual stress is generated in the weld bead, which may reduce the durability of the weld bead. it can.

  According to the differential gear device for a vehicle according to the third aspect of the invention, the first dimension is set smaller than the thickness dimension in the axial direction of the inner peripheral end of the weld bead formed by the welding. Therefore, even when the penetration depth of the weld bead is shallower than the upper limit value of the required weld depth, the first annular gap is filled with the weld bead that has reached the first annular gap. Therefore, the ring gear and the flange portion are welded so as to penetrate in the radial direction continuously in the circumferential direction. Even if the penetration depth of the weld bead varies, the weld depth in the radial direction between the flange portion and the ring gear, that is, the weld leg length is within the range from the lower limit value to the upper limit value of the required weld depth. The welding leg length can be stabilized.

It is sectional drawing which shows the differential gear apparatus for vehicles of one Example of this invention. It is an enlarged view which expands and shows the II arrow part of the differential gear apparatus shown in FIG. 1, Comprising: It is sectional drawing for demonstrating the welding site | part of a differential case and a ring gear. FIG. 3 is a diagram illustrating a state in which the flange portion and the ring gear of FIG. 2 are combined with each other before being welded to each other. It is sectional drawing for demonstrating the welding site | part of a differential case and a ring gear, Comprising: It is a figure which shows the state by which the penetration depth of the weld bead was made to reach | attain in a 2nd annular clearance. It is a figure which shows a mode that the penetration welding of a flange part and a ring gear is confirmed by nondestructive inspection, for example, ultrasonic inspection. In the differential gear apparatus of the other Example of this invention, it is sectional drawing for demonstrating the welding site | part of a differential case and a ring gear, Comprising: It is a figure corresponding to FIG. In the differential gear apparatus of the other Example of this invention, it is sectional drawing for demonstrating the welding site | part of a differential case and a ring gear, Comprising: It is a figure corresponding to FIG. In the differential gear apparatus of the other Example of this invention, it is sectional drawing for demonstrating the welding site | part of a differential case and a ring gear, Comprising: It is a figure corresponding to FIG.

  Hereinafter, an embodiment 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 cross-sectional view showing a vehicle differential gear device (hereinafter referred to as a differential gear device) 10 according to an embodiment of the present invention. In FIG. 1, a differential gear device 10 includes a pair of side gears 12 opposed to each other on an axis C, and a pair of pinions 14 opposed to each other across the axis C and meshed with the pair of side gears 12, respectively. A differential case 20 having an annular flange portion 18 integrally accommodated from the cylindrical outer peripheral surface 16 to the outer peripheral side and accommodated in a rotatably supported state, and one side surface of the flange portion 18 in the axis C direction And an annular ring gear 26 welded between one end surface 24 abutted on one side surface 22 and the one end surface 24. The differential gear device 10 is provided, for example, in a transmission, a transfer, or a final reduction gear (not shown), and the power input to the ring gear 26 is applied to the pair of side gears 12 while allowing a rotational difference between the pair of side gears 12. Each of the rotating members is connected to, for example, a pair of left and right drive wheels and a pair of front and rear drive axles.

  FIG. 2 is an enlarged view showing the II gear portion of the differential gear device 10 shown in FIG. 1, and is a cross-sectional view for explaining a welded portion between the differential case 20 and the ring gear 26. FIG. 3 is a view showing a state in which the flange portion 18 and the ring gear 26 of FIG. 2 are combined with each other before they are welded to each other. As shown in FIG. 3, one side surface 22 of the flange portion 18 and one end surface 24 of the ring gear 26 are opposed to each other in the direction of the axis C shown in FIG. A pair of contact surfaces 22a and 24a are formed. In FIG. 2, the contact surfaces 22a and 24a shown in FIG. 3 are virtually indicated by a two-dot chain line. These contact surfaces 22a and 24a have inner peripheral edges positioned at a radial position a corresponding to a lower limit value A of a required welding depth predetermined in the radial direction.

  Further, on one side surface 22 of the flange portion 18, a first annular groove 22 b formed adjacent to the inner peripheral side of the contact surface 22 a and an inner peripheral side of the first annular groove 22 b are adjacent. A formed second annular groove 22c is provided.

  As shown in FIGS. 2 and 3, the first annular groove 22b has an outer peripheral edge located at the radial position a, and an inner peripheral edge predetermined in the radial direction, the upper limit B of the required welding depth. Is located at a radial position b corresponding to. The depth of the first annular groove 22b in the direction of the axis C is continuously deeper toward a predetermined first dimension D1 as it goes from the radial position a to the radial intermediate position c. The first dimension D1 is set from the intermediate position c to the radial position b. The depth in the axial center C direction of the first annular groove 22b of the present embodiment is that of the portion on the flange portion 18 side with respect to the one end surface 24 of the weld bead 28 formed by the welding regardless of the radial position. It is set smaller than the thickness dimension t in the direction of the axis C at the inner peripheral end. For example, FIG. 2 shows a state where the penetration depth X1 in the radial direction of the weld bead 28 coincides with the depth corresponding to the intermediate position c, but at the intermediate position c of the first annular groove 22b. The first dimension D1 which is the depth in the axial center C direction is set to be smaller than the thickness dimension t in the axial center C direction of the inner peripheral end of the weld bead 28 on the flange portion 18 side with respect to the one end surface 24. ing. Therefore, in the first annular groove 22 b of this embodiment, a portion located on the outer peripheral side of the inner peripheral end of the weld bead 28 is filled with the weld bead 28. In other words, the depth of the first annular groove 22b in the direction of the axis C is set to be filled by the welding. When the penetration depth X1 of the weld bead 28 exceeds the lower limit value A of the required welding depth and is not more than the upper limit value B, the welding depth in the radial direction between the flange portion 18 and the ring gear 26, that is, welding. The leg length X2 is equal to the penetration depth X1 of the weld bead 28.

  By providing the first annular groove 22b as described above, a diameter corresponding to the lower limit value A of the required welding depth in the welding is provided at a position adjacent to the inner peripheral side of the pair of contact surfaces 22a and 24a. The outer peripheral edge is positioned at the direction position a, the inner peripheral edge is positioned at the radial position b corresponding to the upper limit B of the required welding depth in the welding, and the axial center C direction of the flange portion 18 and the ring gear 26 Is provided with a first annular gap 30 set to be equal to or smaller than the first dimension D1 filled by the welding.

  The outer peripheral edge of the second annular groove 22c is positioned at the radial position b. In the present embodiment, the inner peripheral edge of the second annular groove 22 c is in contact with the one end face 24 of the ring gear 26. A portion of the side surface 22 of the flange portion 18 adjacent to the inner peripheral side of the second annular groove 22 c is brought into contact with the one end surface 24 of the ring gear 26. The depth in the direction of the axis C of the second annular groove 22c is set to a predetermined second dimension D2. The second dimension D2 is set larger (deeper) than the thickness dimension t in the axial center C direction of the inner peripheral end of the portion on the flange 18 side with respect to the one end surface 24 of the weld bead 28 formed by welding. ing. For example, FIG. 4 shows a state where the penetration depth X1 in the radial direction of the weld bead 28 is larger than the upper limit value B of the required welding depth, and the first annular groove 22b at that depth. The second dimension D2 that is the depth in the direction of the axis C is larger than the thickness dimension t in the direction of the axis C of the inner peripheral end of the weld bead 28 on the flange 18 side with respect to the one end surface 24. Accordingly, the second annular groove 22c of the present embodiment is not filled with the weld bead 28. In other words, the depth (second dimension D2) in the direction of the axis C of the second annular groove 22c is set so as not to be filled by the welding. When the penetration depth X1 of the weld bead 28 exceeds the upper limit value B of the required welding depth, the radial welding depth of the flange portion 18 and the ring gear 26, that is, the welding leg length X2, is the required welding depth. It becomes equal to the upper limit B of the height.

  By providing the second annular groove 22c as described above, a radial position b corresponding to the upper limit value B of the required welding depth in the welding is provided at a position adjacent to the inner peripheral side of the first annular gap 30. The second annular gap 32 is set to a second dimension D2 that is larger than the first dimension D1 that is not filled by the welding, and the distance between the flange 18 and the ring gear 26 in the direction of the axis C is not filled. Is provided.

  The differential case 20 is made of a metal such as cast iron manufactured through processes such as casting, cutting, and grinding. The ring gear 26 is made of metal such as alloy steel manufactured through processes such as cutting, gear cutting, and heat treatment. As shown in FIG. 3, the differential case 20 and the ring gear 26 are in a state where the contact surface 22 a of the one side surface 22 of the flange portion 18 and the contact surface 24 a of the one end surface 24 of the ring gear 26 are in contact with each other. The one side surface 22 and the one end surface 24 are welded to each other by the laser beam L irradiated from the outer peripheral side.

  For example, the output of the laser beam L is experimentally obtained and set in advance so that the average value of the variation range of the penetration depth X1 of the weld bead 28 substantially matches the upper limit value B of the required welding depth. The Further, the output of the laser beam L is such that, for example, the minimum value of the variation range of the penetration depth X1 of the weld bead 28 formed by laser beam welding is larger than the lower limit value A of the required welding depth. Preliminarily obtained experimentally and set. Since the outer peripheral edge of the first annular gap 30 is positioned at the radial position a corresponding to the lower limit value A of the required welding depth, welding of the flange portion 18 and the ring gear 26 by the laser beam L is performed at the flange portion. 18 and a weld bead 28 having a depth reaching the first annular gap 30 from the outer peripheral side of the ring gear 26 are continuously formed in the circumferential direction. Therefore, for example, even when the penetration depth X1 of the weld bead 28 varies and the penetration depth X1 may become shallower than the upper limit B of the required welding depth as shown in FIG. The portion 18 and the ring gear 26 are welded so as to penetrate in the radial direction continuously in the circumferential direction.

  FIG. 5 is a view showing a state in which penetration welding between the flange portion 18 and the ring gear 26 is confirmed by nondestructive inspection, for example, ultrasonic inspection. As shown in FIG. 5, in the ultrasonic inspection, for example, from the probe 36 brought into contact with the side surface opposite to the one side surface 24 of the flange portion 18 toward the one side surface 24 inside the flange portion 18. A convergent ultrasonic beam S is emitted. Then, the reflected wave of the ultrasonic beam S at the discontinuous portion adjacent to the inner peripheral side of the weld bead 28, that is, the first annular gap 30 is detected, and the radial direction of the outer peripheral edge of the first annular gap 30 is detected. By confirming the position, the radial depth L of the inner peripheral end of the weld bead 28 corresponding to the penetration depth X1 of the weld bead 28 is measured. When the radial depth L of the inner peripheral end of the weld bead 28 is larger than the lower limit value A of the required welding depth, it is determined that the welding is through welding, and the radial depth L is the lower limit of the required welding depth. When the value is A or less, it is determined that non-penetrating welding is performed. In the present embodiment, for example, the spot diameter D3 of the ultrasonic beam S is set to be smaller than the difference (B−A) between the upper limit value B and the lower limit value A of the necessary welding depth. The measurement error of L is set to be between the lower limit value A and the upper limit value B of the required welding depth.

  As described above, according to the differential gear device 10 of the present embodiment, the inner peripheral side of the pair of contact surfaces 22a and 24a that are brought into contact with each other before the flange portion 18 and the ring gear 26 are welded by the laser beam L. Is positioned at a radial position a corresponding to the lower limit value A of the required welding depth in the welding, and a radial position corresponding to the upper limit value B of the required welding depth in the welding. b is provided with a first annular gap 30 in which the inner peripheral edge is positioned and the interval in the direction of the axis C is set to be equal to or smaller than the first dimension D1 filled by the welding, and the variation in the penetration depth X1 of the weld bead 28 is provided. Since the welding is performed so that the minimum value of the range is larger than the lower limit value A of the required welding depth, even if the penetration depth X1 of the weld bead 28 varies, the flange portion 18 and the ring gear 6 and is welded to penetrate radially circumferentially continuous. Further, an outer peripheral edge is positioned at a radial position b corresponding to the upper limit value B of the required welding depth in the welding at a position adjacent to the inner peripheral side of the first annular gap 30, and an interval in the axis C direction. Is provided with a second annular gap 32 set to a second dimension D2 larger than the first dimension D1 that is not filled by the welding, so that the penetration depth X1 exceeds the upper limit B of the required welding depth. Even in this case, the welding depth in the radial direction between the flange portion 18 and the ring gear 26, that is, the welding leg length X2, does not exceed the upper limit B of the necessary welding depth. Therefore, it is possible to prevent the radial welding depth, that is, the weld leg length X2 from becoming deeper than necessary, while continuously welding the flange portion 18 and the ring gear 26 in the circumferential direction.

  In addition, according to the differential gear device 10 of the present embodiment, the welding between the flange portion 18 and the ring gear 26 by the laser beam L reaches the first annular gap 30 from the outer peripheral side of the flange portion 18 and the ring gear 26. Since the weld bead 28 is continuously formed in the circumferential direction, the flange portion 18 and the ring gear 26 are welded so as to penetrate in the radial direction continuously in the circumferential direction. Therefore, for example, when the flange portion 18 and the ring gear 26 are not continuously welded in the circumferential direction, the contact surface 22a of the one side surface 22 of the flange portion 18 is positioned adjacent to the inner peripheral side of the weld bead 28. When the weld bead 28 is solidified and contracts after welding, a tensile residual stress is generated in the weld bead 28 when the weld bead 28 solidifies and contracts after welding. However, such a situation can be prevented.

  Further, according to the differential gear device 10 of the present embodiment, the first dimension D1 is the flange portion 18 with respect to the one end surface 24 of the weld bead 28 formed by welding the flange portion 18 and the ring gear 26 with the laser beam L. In this case, the penetration depth X1 of the weld bead 28 is shallower than the upper limit value B of the required welding depth because it is set smaller than the thickness dimension t in the axial center C direction of the inner peripheral end of the side portion. Even so, since the first annular gap 30 is filled with the weld bead 28 that reaches the first annular gap 30, the ring gear 26 and the flange portion 18 continuously penetrate in the circumferential direction in the radial direction. Welded. Even if the penetration depth X1 of the weld bead 28 varies, the welding depth in the radial direction between the flange portion 18 and the ring gear 26, that is, the weld leg length X2, is from the lower limit value A to the upper limit value B of the required welding depth. Therefore, the welding leg length X2 can be stabilized.

  Next, another embodiment of the present invention will be described. In the following description of the embodiments, portions that overlap each other are denoted by the same reference numerals and description thereof is omitted.

  FIG. 6 is a cross-sectional view for explaining a welded portion between the differential case 20 and the ring gear 26 in the differential gear device 40 of another embodiment of the present invention, and corresponds to FIG. 2 of the first embodiment. FIG. As shown in FIG. 2, one side surface 46 of the flange portion 44 and the one end surface 24 of the ring gear 26 of the present embodiment are opposed to each other in the direction of the axis C and abut against each other before they are welded to each other. A pair of contact surfaces 46a and 24a are formed. These abutting surfaces 46a and 24a have inner peripheral edges positioned at a radial position a corresponding to a lower limit value A of a required welding depth predetermined in the radial direction. Also, on one side 46 of the flange portion 44, a first annular groove 46b formed adjacent to the inner peripheral side of the contact surface 46a, and an inner peripheral side of the first annular groove 46b are adjacent. A formed second annular groove 46c is provided. The first annular groove 46b is configured similarly to the first annular groove 24b of the first embodiment. The second annular groove 46c is configured in the same manner as the second annular groove 24c of the first embodiment except that the inner peripheral edge communicates with the cylindrical outer peripheral surface 16.

  By providing such a second annular groove 46c, a position adjacent to the inner peripheral side of the first annular gap 30 is at a radial position b corresponding to the upper limit B of the required welding depth in the welding. A second annular gap 48 is provided in which the outer peripheral edge is positioned and the interval in the direction of the axis C is set to a second dimension D2 larger than the first dimension D1 that is not filled by the welding.

  According to the differential gear device 40 of the present embodiment, the configuration other than the above is the same as that of the first embodiment described above, and abuts one side surface 46 of the flange portion 44 and the one end surface 24 of the ring gear 26 before welding. An outer peripheral edge is positioned at a radial position a corresponding to the lower limit value A of the required welding depth in the welding at a position adjacent to the inner peripheral side of the pair of contact surfaces 46a and 24a. An inner peripheral edge is positioned at a radial position b corresponding to the upper limit B of the required welding depth, and a first annular gap 30 is set in which the interval in the direction of the axis C is set to be equal to or smaller than the first dimension D1 filled by the welding. Since the welding is performed such that the minimum value of the variation range of the penetration depth X1 of the weld bead 28 is larger than the lower limit value A of the required welding depth, the penetration depth of the weld bead 28 is Variation in length X1 Also, the flange portion 44 and the ring gear 26 is welded to penetrate radially circumferentially continuous. Further, an outer peripheral edge is positioned at a radial position b corresponding to the upper limit value B of the required welding depth in the welding at a position adjacent to the inner peripheral side of the first annular gap 30, and an interval in the axis C direction. Is provided with a second annular gap 48 set to a second dimension D2 larger than the first dimension D1 that is not filled by the welding, so that the penetration depth X1 exceeds the upper limit B of the required welding depth. Even in this case, the welding depth in the radial direction between the flange portion 18 and the ring gear 26, that is, the welding leg length X2, does not exceed the upper limit B of the necessary welding depth. Therefore, as in the first embodiment, it is possible to suppress the welding depth in the radial direction, that is, the weld leg length X2 from becoming deeper than necessary, while continuously welding the flange portion 44 and the ring gear 26 in the circumferential direction. The effect that it can be obtained.

  FIG. 7 is a cross-sectional view showing a state in which the flange portion 54 and the ring gear 56 of the differential case 52 are combined with each other in the differential gear device 50 according to another embodiment of the present invention. FIG. 6 is a diagram corresponding to FIG. 3 of the first embodiment. As shown in FIG. 7, the one side surface 58 of the flange portion 54 and the one end surface 60 of the ring gear 56 of the present embodiment are opposed to each other in the axial center C direction and abutted with each other before they are welded to each other. A pair of contact surfaces 58a and 60a are formed. These contact surfaces 58a and 60a have their inner peripheral edges positioned at a radial position a corresponding to a lower limit value A of a required welding depth predetermined in the radial direction. Further, a first annular groove 60b formed adjacent to the inner peripheral side of the contact surface 60a and a first annular groove 60b adjacent to the inner peripheral side of the first annular groove 60b are formed on one side surface 60 of the ring gear 56. The second annular groove 60c is provided. The first annular groove 60b and the second annular groove 60c have a symmetrical shape with respect to the one side surface 58 as compared with the first annular groove 24b and the second annular groove 24c of the first embodiment. Configured.

  By providing the first annular groove 60b, the radial position a corresponding to the lower limit A of the required welding depth in the welding is provided at a position adjacent to the inner peripheral side of the pair of contact surfaces 58a and 60a. The inner peripheral edge is positioned at the radial position b corresponding to the upper limit value B of the required welding depth in the welding, and the distance between the flange portion 18 and the ring gear 26 in the axial center C direction is set. A first annular gap 62 set to be equal to or smaller than the first dimension D1 filled by the welding is provided. Further, by providing the second annular groove 60c, the position adjacent to the inner peripheral side of the first annular gap 62 is at a radial position b corresponding to the upper limit B of the required welding depth in the welding. There is a second annular gap 64 in which the outer peripheral edge is positioned and the distance between the flange portion 18 and the ring gear 26 in the axial center C direction is set to a second dimension D2 that is larger than the first dimension D1 that is not filled by the welding. Is provided.

  According to the differential gear device 50 of the present embodiment, the configuration other than the above is the same as that of the above-described first embodiment. Therefore, even if the penetration depth X1 of the weld bead 28 varies, The ring gear 56 and the ring gear 56 are continuously welded through in the radial direction, and the flange portion 54 and the ring gear 56 are welded even when the penetration depth X1 exceeds the upper limit value B of the required welding depth. The weld depth in the radial direction, that is, the weld leg length X2, does not exceed the upper limit B of the required weld depth. Accordingly, as in the first embodiment, it is possible to prevent the welding depth in the radial direction, that is, the weld leg length X2 from becoming deeper than necessary, while continuously welding the flange portion 54 and the ring gear 56 in the circumferential direction. The effect that it can be obtained.

  FIG. 8 is a cross-sectional view showing a state where the flange portion 18 of the differential case 20 and the ring gear 56 are combined with each other in the differential gear device 70 of another embodiment of the present invention before they are welded to each other. FIG. 6 is a diagram corresponding to FIG. 3 of the first embodiment. As shown in FIG. 8, the position adjacent to the inner peripheral side of the pair of contact surfaces 22a and 60a of this embodiment is outside the radial position a corresponding to the lower limit A of the required welding depth in the welding. The peripheral edge is positioned and the inner peripheral edge is positioned at a radial position b corresponding to the upper limit B of the required welding depth in the welding, and the distance between the flange portion 18 and the ring gear 56 in the axis C direction is the welding distance. Is provided with a first annular gap 72 set to be equal to or smaller than the first dimension D1. Further, an outer peripheral edge is located at a radial position b corresponding to the upper limit value B of the required welding depth in the welding at a position adjacent to the inner peripheral side of the first annular gap 72, and the flange portion 18 and the ring gear A second annular gap 74 having a second dimension D2 that is larger than a first dimension D1 that is not filled with the welding by a distance in the axial center C direction from 56 is provided.

  According to the differential gear device 70 of the present embodiment, the configuration other than the above is the same as that of the above-described first embodiment. Therefore, even if the penetration depth X1 of the weld bead 28 varies, the flange portion 18 The ring gear 56 and the ring gear 56 are continuously welded through in the radial direction and welded, and even when the penetration depth X1 exceeds the upper limit B of the required welding depth, the flange portion 18 and the ring gear 56 are used. The weld depth in the radial direction, that is, the weld leg length X2, does not exceed the upper limit B of the required weld depth. Therefore, as in the first embodiment, it is possible to suppress the welding depth in the radial direction, that is, the weld leg length X2 from becoming deeper than necessary, while continuously welding the flange portion 18 and the ring gear 56 in the circumferential direction. The effect that it can be obtained.

  As mentioned above, although one Example of this invention was described in detail with reference to drawings, this invention is not limited to this Example, It can implement in another aspect.

  For example, in the above-described embodiment, the cross-sectional shapes of the first annular groove 22b (46b, 60b) and the second annular groove 22c (46c, 60c) are only examples, and other cross-sectional shapes are shown. It may have. For example, the first annular concave groove 22b (46b, 60b) may be formed such that the depth in the axial center C direction continuously increases from the radial position a to the radial position b. The first dimension D1 may be uniformly set from the direction position a to the radial position b. Further, the second annular groove 22c (46c, 60c) has a depth in the direction of the axis C from the first dimension D1 of the inner peripheral edge of the first annular groove 22b (46b, 60b) as in this embodiment. It may be formed so as to increase in two dimensions D2 stepwise, that is, discontinuously, and the depth in the axis C direction from the inner peripheral edge to the inner peripheral side of the first annular groove 22b (46b, 60b). You may form so that it may become large continuously. Preferably, the depth of the second annular groove 22c (46c, 60c) in the direction of the axis C is increased stepwise from the first dimension D1 to the second dimension D2, and the second annular groove The corners on the outer peripheral side of 22c are formed at a right angle or with a sufficiently small radius of curvature so as to be approximately a right angle. Thereby, even when the weld bead 28 reaches the inner peripheral side from the radial position b, the weld leg length X2 does not become larger than the upper limit B of the required welding depth.

  In the above-described embodiment, the flange portions 18 (44, 54) and the ring gear 26 (56) are welded to each other by laser beam, but may be welded by, for example, electron beam welding or other welding.

  It should be noted that the above description is merely an embodiment, and other examples are not illustrated. However, the present invention is implemented in variously modified and improved modes based on the knowledge of those skilled in the art without departing from the gist of the present invention. Can do.

10, 40, 50, 70: Vehicle differential gear device 12: Side gear 14: Pinion 16: Cylindrical outer peripheral surfaces 18, 44, 54: Flange portions 20, 42, 52: Differential cases 22, 46, 58: One side surface 22a 24a, 46a, 58a, 60a: contact surface 24, 60: one end face 26, 56: ring gear 28: weld bead 30, 62, 72: first annular gap 32, 48, 64, 74: second annular gap A : Lower limit value of necessary welding depth B: Upper limit value of necessary welding depth C: Center axis D1: First dimension a: Radial position corresponding to lower limit value of necessary welding depth b: Upper limit value of necessary welding depth Radial position t corresponding to: thickness dimension

Claims (3)

A differential case having a pair of side gears opposed to each other and a pinion meshing with them in a state where the pinion is rotatably supported and having an annular flange portion integrally projecting from the cylindrical outer peripheral surface to the outer peripheral side; An annular ring gear welded between one side surface in the axial direction of the flange portion and one end surface brought into contact with the one side surface, and the power input to the ring gear is transmitted to the pair of side gears. A differential gear device for a vehicle that transmits to a rotating member connected to the pair of side gears while allowing a rotation difference,
On one side surface of the flange portion and one end surface of the ring gear, an inner peripheral edge is positioned at a radial position corresponding to a lower limit value of a required welding depth predetermined in the radial direction in the mutual welding, and the welding is performed. A pair of abutting surfaces that are brought into contact with each other before are formed,
An inner peripheral edge is positioned at a radial position corresponding to an upper limit value of a required welding depth predetermined in the radial direction in the welding at a position adjacent to the inner peripheral side of the pair of contact surfaces that are in contact with each other. A first annular gap set to be equal to or less than a first dimension in which the axial distance between the flange portion and the ring gear is filled by the welding,
In a position adjacent to the inner peripheral side of the first annular gap, a second annular ring in which the axial distance between the flange portion and the ring gear is set larger than the first dimension that is not filled by the welding. A differential gear device for a vehicle, wherein a gap is provided.   The welding between the flange portion and the ring gear is to continuously form a weld bead having a depth reaching the first annular gap from the outer peripheral side of the flange portion and the ring gear in the circumferential direction. The vehicle differential gear device according to claim 1.   3. The vehicle differential gear device according to claim 1, wherein the first dimension is set to be smaller than a thickness dimension in an axial direction of an inner peripheral end of a weld bead formed by the welding. .

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