JP2012137113A - Shaft device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft device that reliably prevents a shaft stored in a housing from falling out and has high flexibility of the design.SOLUTION: A differential device includes: a differential case 40 formed with a storing hole 43; a pinion shaft 50 stored inside the storing hole 43; and a snap ring 70 assembled to an outer peripheral of the differential case 40 and disposed crossing over the storing hole 43. A fitting groove 54 extended in a direction is formed in an end surface of the pinion shaft 50. The snap ring 70 includes: a body 71 extended while encircling the differential case 40; and a bar-like protrusion 75 mounted to an inner peripheral surface of the body 71 and fitting to the fitting groove 54.

Description

  The present invention relates to a shaft device, and more particularly, to a shaft device including a shaft and a housing that houses the shaft.

  Conventionally, various techniques for preventing a pinion shaft from coming off from a differential case have been proposed for differential devices mounted on vehicles such as automobiles. For example, Patent Document 1 discloses a technique in which both end surfaces of a pinion shaft interfere with a ring gear to prevent the pinion shaft from coming off in the axial direction, and the ring gear and the pinion shaft are locked to prevent the pinion shaft from rotating. Has been proposed.

  In Patent Document 2, a pinion shaft is inserted into a through hole provided in the peripheral wall portion of the differential case, and a pin is inserted into a pin insertion hole formed in the peripheral wall portion of the differential case in a direction perpendicular to the through hole. A technique for preventing the pinion shaft from coming off and preventing it from rotating by locking the pin to the pinion shaft has been proposed. Patent Document 3 proposes a technique for preventing a pinion shaft from coming off by causing a bolt screwed into a differential case to project its tip portion to a position facing the end surface of the pinion shaft.

JP-A-10-141474 JP 2008-128440 A Japanese Patent Laid-Open No. 9-089073

  In Patent Document 1, a pinion shaft is prevented from rotating and coming off using a ring gear for transmitting a rotational force input from a driving force source to a differential device. In this case, it is necessary to arrange the ring gear at a position facing the end face of the pinion shaft. Therefore, the arrangement of the ring gear is limited, and there is a problem that the degree of freedom in designing the differential device is low.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a shaft device that can reliably prevent a shaft accommodated in a housing from being detached and has a high degree of freedom in design. It is.

  A shaft device according to the present invention includes a housing in which a through-hole is formed, a shaft housed in the through-hole, a snap ring that is assembled to the outer periphery of the housing and disposed beyond the through-hole, Is provided. A fitting groove extending in one direction is formed on the end surface of the shaft. The snap ring includes a main body that extends around the housing, and a rod-shaped protrusion that is attached to the inner peripheral surface of the main body and fits into the fitting groove.

  Preferably, in the shaft device, the fitting grooves are formed on both sides of the end surface of the shaft. The fitting grooves may be formed in parallel to each other.

  Preferably, in the above shaft device, an assembly groove extending to reach the through hole is formed on the outer surface of the housing. The assembly groove and the fitting groove may be formed to be continuous with each other.

  Preferably, in the above shaft device, the rod-shaped protrusion extends in a direction orthogonal to the extending direction of the main body.

  According to the present invention, it is possible to reliably prevent the shaft accommodated in the casing from coming off, and to improve the degree of freedom in designing the shaft device.

It is sectional drawing of the differential gear according to Embodiment 1 of this invention. It is a fragmentary sectional view of the differential which shows the area | region II vicinity shown in FIG. FIG. 2 is a plan view of the differential device shown in FIG. 1. FIG. 4 is a partial plan view of a differential device showing a region IV and its vicinity shown in FIG. 3 in an enlarged manner. It is a front view of a snap ring. It is a side view of a snap ring. It is a top view of a pinion shaft. It is a front view of a pinion shaft. It is sectional drawing of the pinion shaft which follows the IX-IX line in FIG. It is the schematic before the assembly | attachment of a snap ring. It is the schematic which shows the 1st step at the time of the assembly | attachment of a snap ring. It is the schematic which shows the 2nd step at the time of the assembly | attachment of a snap ring. It is a fragmentary top view which shows the state which a rod-shaped protrusion rotates with a pinion shaft. FIG. 5 is a partial plan view of a differential device according to a second embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view of differential device 1 according to the first embodiment of the present invention. The differential device 1 transmits a part of the rotational force input from the driving force source to the left and right wheels via the drive shaft 53. The differential device 1 is accommodated in a differential carrier 10. The differential carrier 10 has a box shape, and has a space for housing each component therein. Oil is present in the differential carrier 10, which cools and lubricates the various mechanisms of the differential 1.

  A drive pinion (not shown) is rotatably held on the differential carrier 10. The drive pinion is meshed with the ring gear 30. A part of the ring gear 30 is immersed in the oil in the differential carrier 10, and the ring gear 30 rotates, so that the oil can be scooped up. The ring gear 30 and the drive pinion mesh with each other so as to have a predetermined backlash. A differential case 40 is connected to the ring gear 30. The ring gear 30 is bolted to the differential case 40 and is held by the differential case 40. The power generated by the driving force source and converted in driving force, rotation speed and rotation direction by the transmission is transmitted to the differential case 40 through the drive pinion and the ring gear 30.

  The differential case 40 holds the pinion shaft 50. A housing hole 43 is formed in the differential case 40. The pinion shaft 50 is inserted into the accommodation hole 43, and the pinion shaft 50 is accommodated in the accommodation hole 43. The pinion shaft 50 extends along the axial direction 100 indicated by the double arrow in FIG. The pinion shaft 50 holds the pinion gear 51 so that it can rotate and revolve. The pair of side gears 52 are arranged so as to mesh with the pinion gear 51. The side gear 52 is spline-fitted with the drive shaft 53, and the rotation of the side gear 52 is transmitted to the drive shaft 53.

  The drive shaft 53 rotates with the differential case 40. The differential case 40 is provided so as to share the rotation shaft 31 that is a virtual rotation center line with the drive shaft 53. The drive shaft 53 is provided so as to be rotatable around the rotation shaft 31, and the differential carrier 10 is fixed. That is, the drive shaft 53 is provided so as to be relatively rotatable around the rotation shaft 31 with respect to the differential carrier 10 surrounding the drive shaft 53.

  The differential case 40 is rotatably held on the differential carrier 10 by a bearing 60. The bearing 60 includes an inner race 61 that contacts the differential case 40, an outer race 63 that contacts the differential carrier 10, and a roller 62 as a rolling element interposed between the inner race 61 and the outer race 63.

  The side gear 52 includes a flat thrust surface 153 orthogonal to the rotation shaft 31, a through hole 151 as an inner peripheral surface positioned on the inner peripheral side of the thrust surface 153, and an outer peripheral surface 152 positioned on the outer peripheral side of the thrust surface 153. And a tooth surface 154 that meshes with the pinion gear. The outer peripheral surface 152 is a cylindrical surface and is disposed in parallel with the rotation shaft 31. The outer peripheral surface 152 is in contact with the inner peripheral surface 41 of the differential case 40. The inner peripheral surface 41 of the differential case 40 with which the outer peripheral surface 152 contacts is also configured in parallel to the rotation shaft 31.

  The drive shaft 53 is fitted into a through hole 151 formed in the side gear 52, and the drive shaft 53 and the side gear 52 rotate integrally. The thrust surface 153 extends from the through hole 151 to the outer peripheral surface 152 and is orthogonal to the rotation shaft 31. The thrust surface 153 is a flat surface without a portion protruding in the direction of the rotation shaft 31. The tooth surface 154 extends linearly. The tooth surface 154 is located on the conical surface, and is configured such that the diameter decreases as the distance from the thrust surface 153 increases. The side gear 52 may be a so-called spiral gear in which the tooth surface 154 is twisted.

  The differential gear that allows the vehicle to run smoothly by giving a rotational difference to the left and right drive shafts 53 when turning or when the road surface is uneven includes a pinion gear 51 and a side gear 52. The pinion gear 51 is attached to the differential case 40, and the side gear 52 is engaged with the pinion gear 51. The side gear 52 is coupled to the drive shaft 53 by a spline.

  When the vehicle goes straight on a flat road, the distance that the left and right drive wheels roll is equal. Therefore, the left and right side gears 52 rotate at the same rotational speed, the pinion gear 51 sandwiched between the side gears 52 does not rotate, and the differential case 40, the pinion gear 51, and the side gear 52 revolve together.

  When the vehicle turns a curve, the rolling distance of the driving wheel outside the curve is longer than the driving wheel inside the curve, so the side gear 52 outside the curve rotates faster than the side gear 52 inside the curve. At this time, the side gear 52 outside the curve rotates faster than the differential case 40, and the side gear 52 inside the curve rotates slower than the differential case 40. Therefore, the pinion gear 51 attached to the differential case 40 and sandwiched between the left and right side gears 52 is not only revolved but also rotated. As a result, power from the differential case 40 can be transmitted to the left and right side gears 52 rotating at different speeds.

  Due to the action of the differential gear, the vehicle can smoothly turn a curve or travel on an uneven road surface without causing a slip between the driving wheel and the road surface.

  Hereinafter, the shaft device according to the present embodiment will be described. The shaft device includes a housing and a shaft accommodated in the housing. In the present embodiment, the casing is the differential case 40 of the vehicle differential device 1, and the shaft is the pinion shaft 50 of the differential device 1. The pinion shaft 50 is configured as a rotation center axis of the pinion gear 51 of the differential device 1.

  FIG. 2 is a partial cross-sectional view of the differential device 1 in which the vicinity of the region II shown in FIG. 1 is enlarged. FIG. 3 is a plan view of the differential device 1 shown in FIG. FIG. 4 is a partial plan view of the differential device 1 showing the vicinity of the region IV shown in FIG. 3 in an enlarged manner. FIG. 5 is a front view of the snap ring 70. FIG. 6 is a side view of the snap ring 70. FIG. 7 is a plan view of the pinion shaft 50. FIG. 8 is a front view of the pinion shaft 50. FIG. 9 is a cross-sectional view of the pinion shaft 50 taken along line IX-IX in FIG. FIG. 1 shows a cross section of the differential device 1 taken along line II in FIG.

  Referring to FIGS. 2 to 9 as appropriate, the differential case 40 is formed with a cylindrical accommodation hole 43 as a through hole penetrating the differential case 40. The pinion shaft 50 is formed in a substantially cylindrical shape and is accommodated in the accommodation hole 43. The pinion shaft 50 has a pair of end surfaces 50a and 50b, and the end surfaces 50a and 50b are formed with elongated and recessed fitting grooves 54 so that parts of the end surfaces 50a and 50b extend in one direction. The fitting groove 54 is formed along the radial direction of the pinion shaft 50 orthogonal to the axial direction 100 shown in FIG. The fitting grooves 54 are formed on both sides of the end surfaces 50 a and 50 b of the pinion shaft 50. The fitting groove 54 formed on the end surface 50a and the fitting groove 54 formed on the end surface 50b extend in the same direction and are formed in parallel to each other.

  A snap ring 70 is assembled on the outer periphery of the differential case 40. The snap ring 70 is arranged so as to make one round of the outer periphery of the differential case 40. The snap ring 70 is disposed beyond the accommodation hole 43 in which the pinion shaft 50 is accommodated. In a state where the pinion shaft 50 is housed in the housing hole 43, the snap ring 70 is disposed so as to face the end faces 50a, 50b on both sides of the pinion shaft. The snap ring 70 extends along the radial direction of the cylindrical accommodation hole 43 and is disposed so as to cross the accommodation hole 43 from one side of the radial direction to the other.

  As shown in FIGS. 5 and 6, the snap ring 70 is attached to an arcuate body portion 71 and an inner peripheral surface 72 of the main body portion 71, and protrudes inward in the radial direction from the inner peripheral surface 72. And a protrusion 75. As shown in FIGS. 1 and 3, the main body 71 of the snap ring 70 extends around the periphery of the differential case 40. The main body portion 71 is formed in a substantially C shape with a part of the annular shape cut out, thereby reducing the rigidity of the main body portion 71 and allowing the main body portion 71 to be easily elastically deformed. Become.

  A grip 76 is provided at the end of the C-shaped main body 71. In the grip portion 76, the width of the main body portion 71 is increased. A through hole 77 is formed in the grip portion 76 so as to penetrate the grip portion 76 in the thickness direction of the main body portion 71. The ease of holding of the gripping portion 76 is enhanced by providing the wide hole and forming the through hole 77. An operator who assembles the snap ring 70 on the outer periphery of the differential case 40 can grip the pair of gripping portions 76 with both hands to elastically deform the snap ring 70 and increase the gap between the end portions of the main body portion 71. By doing so, the snap ring 70 can be easily assembled around the differential case 40.

  The inner peripheral surface 72 of the main body 71 of the snap ring 70 is formed with a flat portion 74 in which a part of the inner peripheral surface 72 is recessed outward in the radial direction. While the main portion of the inner peripheral surface 72 extends in an arc shape, the flat portion 74 is formed to extend in a planar shape. In the place where the flat part 74 is formed, the width | variety of the main-body part 71 is small. The rod-shaped protrusion 75 protrudes radially inward from the flat part 74 and is formed integrally with the main body 71. A portion where the main body portion 71 and the rod-like protrusion 75 are joined together forms a joint portion 78.

  The rod-shaped protrusion 75 extends in a direction orthogonal to the extending direction of the main body 71. The rod-shaped protrusion 75 has, for example, a length that is five times or more the thickness dimension of the main body 71 and is joined to the main body 71 at the center in the longitudinal direction. The rod-shaped protrusion 75 extends along the thickness direction of the main body 71 and protrudes from the main body 71 by the same length from the front surface and the back surface of the main body 71 as shown in FIG.

  The rod-like protrusion 75 is fitted in the fitting groove 54 formed in the both end faces 50a, 50b of the pinion shaft 50. The fitting groove 54 and the rod-shaped protrusion 75 are adjusted in shape and size so that the rod-shaped protrusion 75 can be fitted into the fitting groove 54 with almost no gap. For example, when the rod-shaped protrusion 75 has a quadrangular prism shape, the fitting groove 54 is formed in a cross-sectional quadrangle, and when the rod-shaped protrusion 75 has a triangular prism shape, the fitting groove 54 is formed in a cross-sectional shape triangle. When 75 is cylindrical, the fitting groove 54 is formed in a circular cross-sectional shape. The extension length of the rod-shaped protrusion 75 is equal to the length of the fitting groove 54 or slightly smaller than the length of the fitting groove 54. That is, the extending length of the rod-shaped protrusion 75 is equal to the diameter of the pinion shaft 50 or slightly smaller than the diameter of the pinion shaft 50.

  The main body 71 of the snap ring 70 is disposed around the differential case 40 so as to straddle the end surfaces 50a and 50b of the pinion shaft 50 in a state where the rod-shaped protrusion 75 is mounted in the fitting groove 54. Since the rod-shaped protrusions 75 are evenly arranged in the thickness direction of the main body 71 with respect to the main body 71, when the rod-shaped protrusion 75 is fitted into the fitting groove 54, the main body 71 is connected to the pinion shaft 50. Extends across the diameter.

  The outer surface 42 of the differential case 40 is formed with an assembly groove 44 in which a part of the outer surface 42 is elongated. As shown in FIG. 4, the assembly groove 44 extends so as to reach the accommodation hole 43 formed in the differential case 40, and extends so as to be connected to the fitting groove 54 formed in the pinion shaft 50. The assembly groove 44 on the outer surface 42 of the differential case 40 and the fitting grooves 54 formed on the end surfaces 50a and 50b of the pinion shaft 50 are formed so as to be continuous with each other. The assembly groove 44 and the fitting groove 54 are formed to extend in a direction orthogonal to the axial direction 100 shown in FIG. 1 and to extend in the extending direction of the drive shaft 53. The shape and dimensions of the assembly groove 44 are adjusted so that the rod-shaped protrusion 75 can be accommodated therein.

  The pinion shaft 50 is formed in a substantially cylindrical shape, and two-surface widths 56 and 57 are formed on a part of the outer peripheral surface thereof. As shown in FIGS. 8 and 9, the two-sided width 56 is constituted by processed surfaces 56 a and 56 b in which a part of the outer peripheral surface of the cylindrical pinion shaft 50 is cut flat. The pair of processed surfaces 56a and 56b are formed in parallel to each other. The two-surface width 57 is constituted by processed surfaces 57a and 57b in which a part of the outer peripheral surface of the cylindrical pinion shaft 50 is processed flat. The pair of processed surfaces 57a and 57b are formed in parallel to each other.

  As shown in FIG. 1, the two-surface widths 56 and 57 are formed at positions where the outer peripheral surface of the pinion shaft 50 faces the pinion gear 51 in the longitudinal direction of the pinion shaft 50. By forming the two-surface widths 56 and 57, a gap is formed between the outer peripheral surface of the pinion shaft 50 facing the pinion gear 51 and the pinion gear 51. This gap is used as a space for supplying lubricating oil to the pinion gear 51 that rotates relative to the pinion shaft 50.

  In the circumferential direction of the pinion shaft 50, two-surface widths 56 and 57 are formed at positions orthogonal to the rotation direction of the pinion shaft 50 that rotates around the rotation shaft 31 together with the differential case 40. On the outer peripheral surface of the pinion shaft 50 facing the pinion gear 51 in the rotation direction of the pinion shaft 50 rotating around the rotation shaft 31, no two-plane width is formed, and no gap is formed between the pinion shaft 50 and the pinion gear 51. . In the direction in which a load is applied to the pinion shaft 50 when the pinion shaft 50 revolves around the rotation shaft 31, the outer peripheral surface of the pinion shaft 50 is formed into a circumferential surface shape.

  Accordingly, the rotational force transmitted from the ring gear 30 to the pinion shaft 50 via the differential case 40 can be efficiently transmitted from the pinion shaft 50 to the pinion gear 51, and the pinion gear 51 can revolve around the rotation shaft 31. . Further, when torque is transmitted from the pinion shaft 50 to the pinion gear 51, it is possible to avoid stress concentration on a part of the outer peripheral surface of the pinion shaft 50 that contacts the pinion gear 51.

  The fitting grooves 54 of the end surfaces 50a and 50b of the pinion shaft 50 extend along a direction perpendicular to a pair of parallel processing surfaces 56a and 56b (57a and 57b) constituting the two-surface width 56 (57). So that it is formed. The processing surfaces constituting the two-surface widths 56 and 57 shown in FIG. 8 extend in a direction parallel to the paper surface, and the fitting groove 54 extends in a direction perpendicular to the paper surface. The direction perpendicular to the processed surfaces 56a, 56b, 57a, 57b shown in FIG. 9 is the left-right direction in the figure, and the fitting groove 54 also extends in the left-right direction in the figure.

  The assembly of the snap ring 70 to the differential case 40 in the shaft device having the above configuration will be described below. The snap ring 70 is assembled into the fitting groove 54 of the pinion shaft 50 while the rod-shaped protrusion 75 is fitted into the assembly groove 44 formed in the differential case 40. FIG. 10 is a schematic view before the snap ring 70 is assembled. FIG. 11 is a schematic view showing a first stage when the snap ring 70 is assembled. FIG. 12 is a schematic view showing a second stage when the snap ring 70 is assembled.

  As shown in FIG. 10, first, the snap ring 70 is arranged around the differential case 40, and the circumferential direction of the snap ring 70 is such that the rod-shaped protrusions 75 are aligned with the extending direction of the assembly groove 44 formed in the differential case 40. Perform position alignment. Subsequently, the snap ring 70 is moved in the arrow direction shown in FIG. 10 so that the rod-shaped protrusion 75 is accommodated in the assembly groove 44. FIG. 11 shows a state in which a part of the rod-shaped protrusion 75 is fitted into the assembly groove 44 during the movement of the snap ring 70.

  From the arrangement shown in FIG. 11, the snap ring 70 is further moved in the direction of the arrow shown in FIG. 11 so that the rod-shaped protrusion 75 moves from the assembly groove 44 to the inside of the fitting groove 54. FIG. 12 illustrates a state in which the rod-shaped protrusion 75 is disposed over both the assembly groove 44 and the fitting groove 54 while the snap ring 70 is moving. Thereafter, the snap ring 70 is further moved in the direction of the arrow shown in FIG. 12, so that the rod-shaped protrusion 75 shown in FIG. 2 is fitted into the fitting groove 54.

  By forming the assembly groove 44 in the differential case 40, the snap ring 70 can be assembled to the differential case 40 by passing the inside of the assembly groove 44 through the rod-shaped protrusion 75. Since the main body 71 of the snap ring 70 can be assembled to the differential case 40 without greatly elastic deformation, the assembly of the snap ring 70 becomes easy, and the workability of the assembly of the snap ring 70 can be improved.

  The moving direction when the snap ring 70 shown in FIGS. 10 to 12 is assembled is a direction orthogonal to the extending direction of the substantially annular main body 71. Therefore, the groove width of the assembly groove 44 formed in the differential case 40 can be reduced by extending the rod-shaped protrusion 75 in a direction orthogonal to the extension direction of the main body 71, and therefore the assembly groove 44. Thus, the amount of elastic deformation when the snap ring 70 is assembled can be reduced.

  The fitting groove 54 is formed so as to extend in the extending direction of the rod-shaped protrusion 75 in a state assembled to the differential case 40 (that is, the direction orthogonal to the extending direction of the main body 71 of the snap ring 70). The fitting grooves 54 on both sides of the end surfaces 50 a and 50 b of the pinion shaft 50 are formed in parallel to each other so as to extend in a direction orthogonal to the extending direction of the main body 71 of the snap ring 70. The assembly groove 44 on the outer surface 42 of the differential case 40 is also formed so as to extend in the same direction as the fitting groove 54, and the assembly groove 44 and the fitting groove 54 are formed to be continuous with each other. In this way, if the snap ring 70 is moved in one direction along the rotation shaft 31 shown in FIG. 1, the rod-shaped protrusion 75 is moved from the inside of the assembly groove 44 to the fitting groove 54 to be fitted. The snap ring 70 can be easily assembled by fitting into the groove 54.

  When the snap ring 70 is assembled to the differential case 40, the rod-like protrusion 75 of the snap ring 70 is fitted into the fitting groove 54 formed in the pinion shaft 50. At this time, the main body 71 of the snap ring 70 that forms a structure integral with the rod-shaped protrusion 75 is fixed to the outer surface 42 of the differential case 40. The main body 71 of the snap ring 70 is fixed to the differential case 40, and the rod-shaped protrusion 75 of the snap ring 70 is also fixed to the differential case 40. Therefore, the pinion shaft 50 in which the rod-like protrusion 75 is fitted in the fitting groove 54 cannot be rotated with respect to the differential case 40.

  Further, the pinion shaft 50 cannot be moved along the axial direction 100 shown in FIG. 1 with respect to the differential case 40 by holding both sides of the end faces 50a, 50b by the snap ring 70. The snap ring 70 is disposed so as to cover both end faces 50a and 50b of the pinion shaft 50, and the rod-like protrusion 75 is inserted into the fitting groove 54, whereby the pinion shaft 50 is moved relative to the differential case 40 in the axial direction 100. And the rotational movement in the circumferential direction of the pinion shaft 50 having a cylindrical shape is restricted.

  As described above, the snap ring 70 is assembled to the differential case 40 so that the rod-shaped protrusion 75 fits into the fitting groove 54 of the pinion shaft 50, so that both the rotational movement of the pinion shaft 50 and the movement of the axial direction 100 are performed. Can be prevented. By using the snap ring 70 having a simple structure, the rotation of the pinion shaft 50 accommodated in the differential case 40 with respect to the differential case 40 and the prevention of the pinion shaft 50 from coming off from the differential case 40 can be reliably performed. Since it is possible to prevent the pinion shaft 50 from being rotated and prevented from coming off without adjusting the arrangement of other members constituting the differential device 1, the degree of freedom in designing the shaft device can be improved. The fitting grooves 54 are formed on both sides of the end faces 50a and 50b of the pinion shaft 50, and the rod-shaped protrusions 75 are fitted into the fitting grooves 54 on both sides of the end faces 50a and 50b, thereby rotating the pinion shaft 50 more reliably. It can be stopped.

  By restricting the movement of the pinion shaft 50 in both the rotational direction and the axial direction 100, the relative positions of the two-surface widths 56 and 57 formed on the pinion shaft 50 with respect to the pinion gear 51 do not change. Therefore, the oil supply space formed by the two-surface widths 56 and 57 can be held at a predetermined position where the pinion shaft 50 and the pinion gear 51 face each other. Therefore, a good lubrication state between the pinion shaft 50 and the pinion gear 51 can be ensured, so that the arrangement of the two-surface widths 56 and 57 is shifted, and the contact between the pinion shaft 50 and the pinion gear 51 changes to change the pinion shaft 50. It is possible to prevent the damage limit from being lowered. Since the snap ring 70 has the function of preventing the rotation of the pinion shaft 50, it is not necessary to change the special lubrication structure, so that an increase in the cost of the apparatus can be avoided.

  Next, the principle that can prevent the relative movement of the pinion shaft 50 in the axial direction 100 with respect to the differential case 40 when the pinion shaft 50 rotates will be described. In the vehicle differential device 1, when the sliding resistance between the pinion gear 51 and the pinion shaft 50 increases due to a high differential between the left and right wheels or a high load of the vehicle, the pinion shaft 50 is rotated in the circumferential direction. A large rotational torque acts on the pinion shaft 50. Due to this rotational torque, a shearing stress acting to bend the rod-shaped protrusion 75 acts on the rod-shaped protrusion 75 having a function of preventing the rotation of the pinion shaft 50.

  Since the rod-like protrusion 75 of the snap ring 70 is disposed in the fitting groove 54 of the pinion shaft 50, when the rotational torque acts on the pinion shaft 50 and the pinion shaft 50 attempts to rotate relative to the differential case 40, Stress acts on the rod-shaped protrusion 75 from the pinion shaft 50. When the stress acting on the rod-shaped protrusion 75 from the pinion shaft 50 exceeds the proof stress of the rod-shaped protrusion 75, the rod-shaped protrusion 75 is damaged. The rod-shaped protrusion 75 is broken at the joint 78 between the main body 71 and the rod-shaped protrusion 75 where stress is most concentrated. Since the rod-shaped protrusion 75 extends in a direction inclined with respect to the extending direction of the main body 71, the maximum stress acts on the joint 78, and the rod-shaped protrusion 75 is connected to the main body 71 at the joint 78. Separate from.

  Even after the rod-shaped protrusion 75 is damaged, the rod-shaped protrusion 75 is disposed inside the fitting groove 54. Since the rod-like protrusion 75 having the function of preventing the rotation of the pinion shaft 50 breaks and the rod-like protrusion 75 can freely rotate with respect to the main body 71 of the snap ring 70, the circumferential direction of the pinion shaft 50 is reduced. Rotation is possible. The pinion shaft 50 is accommodated in the accommodation hole 43 so as to be rotatable relative to the differential case 40 in a state where the rod-shaped protrusion 75 is broken. On the other hand, the main body 71 of the snap ring 70 is still disposed beyond the accommodation hole 43 formed in the differential case 40 even if the rod-like protrusion 75 is broken, and the end surface 50 a of the pinion shaft 50 is formed outside the accommodation hole 43. 50b is opposed to both.

  FIG. 13 is a partial plan view showing a state in which the rod-shaped protrusion 75 rotates together with the pinion shaft 50. As shown in FIG. 13, the pinion shaft 50 and the broken rod-like protrusion 75 are integrally rotated relative to the differential case 40 by the rotational torque acting on the pinion shaft 50. Even after the rod-shaped protrusion 75 breaks and the snap ring 70 cannot perform the function of preventing the rotation of the pinion shaft 50, the snap ring 70 is disposed by the main body 71 disposed opposite to both the end faces 50 a and 50 b of the pinion shaft 50. The movement of the pinion shaft 50 in the direction in which the pinion shaft 50 comes out of the differential case 40, that is, the axial direction 100 shown in FIG.

  Thus, even when the pinion shaft 50 accommodated in the differential case 40 rotates together with the pinion gear 51, it is possible to suppress a change in the relative position between the differential case 40 and the pinion shaft 50 in the axial direction 100. Therefore, it is possible to prevent the pinion shaft 50 from coming off the differential case 40. Further, since the pinion shaft 50 can be arranged so that the oil supply space formed on the outer peripheral surface of the pinion shaft 50 is interposed between the pinion shaft 50 and the pinion gear 51, the pinion shaft 50 is in a good lubrication state. Can be secured.

  By disposing the rod-like protrusion 75 inside the fitting groove 54, the snap ring 70 restricts the movement of the pinion shaft 50 in the axial direction 100 and also has a function of preventing the rotation of the pinion shaft 50. On the other hand, after the rod-like protrusion 75 is broken, the rod-like protrusion 75 and the pinion shaft 50 are integrally rotated while maintaining the state in which the movement of the pinion shaft 50 in the axial direction 100 is restricted by the main body 71 of the snap ring 70. be able to.

(Embodiment 2)
FIG. 14 is a partial plan view of the differential device 1 according to the second embodiment. FIG. 14 shows an enlargement of a part of the differential device 1 corresponding to the vicinity of the region IV shown in FIG. Compared with FIG. 14 and FIG. 4 showing an enlarged view of the vicinity of the region IV in the first embodiment, the differential device 1 of the second embodiment has an assembly groove 44 formed on the outer surface 42 of the differential case 40. The shape is different from that of the first embodiment.

  Specifically, the assembly groove 44 shown in FIG. 4 is formed to extend linearly, whereas the assembly groove 44 shown in FIG. 14 is separated from the accommodation hole 43 from one end on the accommodation hole 43 side. The groove width increases toward the other end on the side. The assembly groove 44 has the maximum groove width at the end portion on the side that serves as an inlet through which the rod-like protrusion 75 is inserted into the assembly groove 44 when the snap ring 70 is assembled.

  In this way, when the snap ring 70 described with reference to FIGS. 10 to 12 is assembled, the rod-shaped protrusion 75 can be moved into the assembly groove 44 more easily. Therefore, workability at the time of assembling the shaft device can be improved.

  In the above description of the embodiment, the pinion shaft 50 accommodated in the differential case 40 has been described as an example, but the shaft device has been described. However, the device of the present invention can also be applied to other devices. For example, the shaft device of the present invention can be applied to a pinion portion of a planetary gear used for an automatic transmission or a transfer. Further, the shaft device of the present invention can be applied not only to vehicle parts but also to a shaft that is a plain bearing.

  Although the embodiment of the present invention has been described as above, the embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be applied particularly advantageously to a shaft device including a differential case and a pinion shaft of a differential gear mounted on a vehicle.

  1 differential gear, 31 rotating shaft, 40 differential case, 43 receiving hole, 44 assembly groove, 50 pinion shaft, 50a, 50b end face, 51 pinion gear, 54 fitting groove, 56, 57 width across flats, 56a, 56b, 57a , 57b Machining surface, 70 snap ring, 71 body portion, 72 inner peripheral surface, 74 flat portion, 75 rod-shaped projection, 76 gripping portion, 77 through hole, 78 joint portion.

Claims (6)

A housing in which a through hole is formed;
A shaft housed inside the through hole;
A snap ring assembled to the outer periphery of the housing and disposed beyond the through-hole,
A fitting groove extending in one direction is formed on the end surface of the shaft,
The said snap ring is a shaft apparatus containing the main-body part extended around the said housing | casing, and the rod-shaped projection part which is attached to the internal peripheral surface of the said main-body part, and fits into the said fitting groove.   The shaft device according to claim 1, wherein the fitting groove is formed on both sides of the end surface of the shaft.   The shaft device according to claim 2, wherein the fitting grooves are formed in parallel to each other.   The shaft device according to any one of claims 1 to 3, wherein an assembly groove extending to reach the through hole is formed on an outer surface of the housing.   The shaft device according to claim 4, wherein the assembly groove and the fitting groove are formed to be continuous with each other.   The shaft device according to any one of claims 1 to 5, wherein the rod-shaped protrusion extends in a direction orthogonal to an extending direction of the main body.

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