JP2019157973A - Differential device - Google Patents

Abstract

To smoothly discharge a lubricant in a differential case to the outside of the case by a simple oil path structure using mutual mating faces of both case-halved bodies without particularly forming a window hole at the differential case, in a differential device in which the differential case includes a pair of case-halved bodies.SOLUTION: A pair of case-halved bodies C1, C2 have an annular recess 31 and an annular protrusion 32 which are coaxially fit to each other at one and the other of mutual mating faces f1, f2 of the case-halved bodies C1, C2. A tip face of the annular protrusion 32 and an inner bottom face of the annular recess 31 oppose each other with an air gap 33 sandwiched therebetween in an axial direction, an oil groove 34 opened at an inner face Ci of a differential case is formed of the opposing faces in a position separated from a pinion shaft 21 in the axial direction, a shaft hole 40 inserted with the pinion shaft 21 is formed between the mating faces f1, f2, and a clearance space 41 communicating with the oil groove 34 at an end part at the inside of a radial direction, and communicating with the outside of the differential case C at an end part at the outside of the radial direction is interposed between the shaft hole 40 and the pinion shaft 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a differential, particularly a hollow differential case rotatable around a first axis, a differential mechanism housed in the differential case, lubricating oil introducing means capable of introducing lubricating oil from the outside into the differential case, and a differential case A pinion shaft that is coupled to the outer peripheral flange portion and meshes with a drive gear connected to a power source, and a differential mechanism is disposed on a second axis perpendicular to the first axis and supported by the differential case; The present invention relates to a gear having a pinion gear rotatably supported by a pinion shaft, and a pair of side gears meshed with the pinion gear and rotatable about a first axis.

  In the present invention and the present specification, the “axial direction” refers to the axial direction of the differential case (that is, the direction along the first axis), and the “radial direction” refers to the radial direction of the differential case (that is, centered on the first axis). The “circumferential direction” refers to the circumferential direction of the differential case (that is, the circumferential direction of the circle with the first axis as the center line).

  A differential case of the above-described differential device in which a differential case is divided into a pair of case halves that are coupled to each other with each open end face as a mating surface is already known, for example, as disclosed in Patent Document 1 below.

JP 54-38027 A

  In the above-described differential device, the differential mechanism can be assembled or the inner surface of the differential case can be machined in a state in which the pair of case halves constituting the differential case are separated from each other. There is no need to provide a large working window in the differential case. Therefore, even in the differential shown in Patent Document 1, a large working window is not provided in the differential case.

  In such a differential device, the differential case does not have a large window hole, which is advantageous in ensuring the rigidity of the differential case, but on the other hand, smooth discharge of the lubricating oil introduced into the differential case becomes difficult and lubrication is difficult. There is a risk that the oil will deteriorate early, causing problems such as seizure of the differential mechanism.

  In addition, in order to solve the above problem, when a large window hole is additionally processed even in the split type differential case, not only the rigidity strength of the differential case is lowered but also the cost is increased by the additional work of the window hole. There is.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide a differential device that can solve the above-described problems of conventional devices with a simple structure.

  In order to achieve the above object, the present invention provides a hollow differential case rotatable around a first axis, a differential mechanism housed in the differential case, and a lubricating oil capable of introducing lubricating oil into the differential case from the outside. Introducing means and a ring gear coupled to a flange portion on the outer periphery of the differential case and meshing with a drive gear connected to a power source, wherein the differential mechanism is disposed on a second axis perpendicular to the first axis. In the differential having a pinion shaft supported by the differential case, a pinion gear rotatably supported by the pinion shaft, and a pair of side gears that mesh with the pinion gear and can rotate about the first axis, the differential case includes: A pair of case halves coupled to each other with each open end face serving as a mating surface, and the pair of case halves are connected to each other on the first axis. An annular concave portion and an annular convex portion that are fitted to each other are provided on one and the other of the mating surfaces, and the tip surface of the annular convex portion and the inner bottom surface of the annular concave portion are opposed to each other with a gap in the axial direction. In addition, an oil groove that opens to the inner surface of the differential case is formed at a position spaced apart from the pinion shaft in the axial direction by the opposing surfaces, and the pinion shaft is inserted between the mating surfaces. A shaft hole is formed, and between the shaft hole and the pinion shaft, a radially inner end communicates with the oil groove and a radially outer end communicates with the outside of the differential case. The first feature is that a gap space serving as an oil passage is interposed.

  According to the present invention, in addition to the first feature, the annular convex portion is partially cut away in a circumferential direction at a portion corresponding to the pinion shaft, and the oil groove and the gap space are interposed through the cutout portion. Is a second feature.

  According to the present invention, in addition to the second feature, a pinion support surface that rotatably supports the back surface of the pinion gear via a pinion washer is formed in a concave shape on the inner surface of the differential case, A third feature is that the opening to the inner surface of the differential case is disposed on the axially outer side of the contact surface of the pinion support surface with the pinion washer.

  Furthermore, in addition to any one of the first to third features, the present invention provides a mating surface of one case half having the annular recess with respect to the other case half in a plane perpendicular to the first axis. A groove portion having a U-shaped cross section that forms the shaft hole in cooperation with the flat surface is recessed in the mating surface of the other case half formed with the one case half. Is the fourth feature.

  According to the first feature, a part of the lubricating oil in the differential case is formed on the mating surfaces of the pair of case halves (particularly, the opposing surfaces of the annular convex portion and the annular concave portion that are concentrically fitted) by centrifugal force. It enters the oil groove and reaches the shaft hole formed between the mating surfaces of both case halves. Then, the reached lubricating oil flows in the gap space between the shaft hole and the pinion shaft, that is, the oil passage to the radially outer side by the action of centrifugal force, and from the radially outer end of the oil passage to the outside of the differential case. To be discharged. As a result, without specially providing a large window hole in the differential case, the lubricating oil in the differential case can be smoothly discharged out of the case, and the oil for lubricating the differential mechanism can be efficiently distributed inside and outside the differential case. This can contribute to preventing seizure of each part of the mechanism. In addition, the oil groove and the clearance space in the shaft hole, which serve as the lubricating oil discharge path, use the clearance between the mating surfaces of the two case halves, thus simplifying the structure of the lubricating oil discharge path. And can greatly contribute to cost savings.

  According to the second feature, the annular convex portion provided on one of the mating surfaces of both case halves is partially cut away in the circumferential direction at a portion corresponding to the pinion shaft, and oil is passed through the cutout portion. Since the groove and the gap space communicate with each other, a simple communication structure in which a notch is provided in the annular convex portion provides a communication path between the oil groove and the gap space, thereby further simplifying the structure. Can contribute to cost savings.

  According to the third feature, the inner surface of the differential case is formed with a concave pinion support surface that rotatably supports the back surface of the pinion gear via a pinion washer, and the oil groove has an opening to the inner surface of the differential case. Since the pinion support surface is disposed on the axially outer side than the pinion washer contact surface, even if the clearance space serving as the oil passage is formed in the shaft hole as described above, the clearance space in the radial direction The opening on the end side can be closed by the pinion washer or the back surface of the pinion gear. Moreover, since the oil groove opening can be sufficiently offset axially outward from the pinion washer contact surface of the pinion shaft or pinion support surface, the maximum diameter portion of the inner surface of the differential case (i.e., the corresponding portion of the pinion shaft or pinion gear) The lubricating oil can be easily stored in the entire peripheral area including the oil, and the amount of lubricating oil flowing out from the maximum diameter portion toward the oil groove or the gap space can be suppressed. Thereby, each part (for example, tooth part, back, pinion shaft fitting part, etc.) of the pinion gear can be efficiently lubricated.

  According to the fourth feature, the mating surface of one case half having an annular recess with respect to the other case half is formed in a plane perpendicular to the first axis, and one case half of the other case half A groove portion having a U-shaped cross section that forms a shaft hole in cooperation with the flat surface is formed in the mating surface with the case half body so that one case half body is flattened with the mating surface. As a result, the structure is simplified and the machining is facilitated. Also, the U-shaped groove need only be formed in the mating surface of the other case half to obtain the shaft hole. Since drilling is not required, machining is easy and it can greatly contribute to cost saving.

The longitudinal cross-sectional view (1-1 sectional view taken on the line of FIG. 2) which shows the differential which concerns on one Embodiment of this invention, and its peripheral device. Right side view of the above-described differential device, with the transmission case, axle, bearings, and gears of the differential mechanism omitted. Right side view showing the differential case of the above differential unit alone (corresponding to FIG. 2) A perspective view of the first case half as viewed from the mating surface f1 side The perspective view which looked at the 2nd case half and the pinion washer from the mating face f2 side 6-6 enlarged sectional view of FIG. 7-7 enlarged cross-sectional view of FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  In FIG. 1, a transmission case 9 of a vehicle (for example, an automobile) houses a differential device D that distributes power from a power source (not shown) (for example, an in-vehicle engine) to the left and right axles 11 and 12 for transmission. The The differential device D includes a differential case C and a differential mechanism 20 built in the differential case C.

  The differential case C is divided into left and right first and second case halves C1 and C2 that are detachably coupled to each other with their open end faces as mating faces f1 and f2.

  The left and right first and second case halves C1 and C2 are integrally connected to the main body portions Cm1 and Cm2 formed in a substantially hemispherical shape and the axially outer portions of the main body portions Cm1 and Cm2, and extend in the axial direction. Bearing bosses Cb1 and Cb2 and flange halves Cf1 and Cf2 that are integrally formed radially outwardly on the outer periphery of the body portions Cm1 and Cm2 and extend in the circumferential direction around the first axis X1 are provided. ing.

  The left and right bearing bosses Cb1 and Cb2 are rotatably supported around the first axis X1 by the transmission case 9 via bearings 13 and 14 on the outer peripheral side thereof. In addition, left and right axles (drive shafts) 11 and 12 are rotatably fitted to the inner peripheral surfaces of the left and right bearing bosses Cb1 and Cb2, and spiral grooves 15 and 16 (FIG. 1) for drawing lubricating oil. , See FIG. 4). The spiral grooves 15 and 16 can exhibit a screw pump action that feeds the lubricating oil in the transmission case 9 into the differential case C as the bearing bosses Cb1 and Cb2 and the axles 11 and 12 rotate relative to each other. This is an example of the lubricating oil introducing means.

  The first and second case halves C1 and C2 are in a state where the opposed open end surfaces of the left and right body portions Cm1 and Cm2 are abutted and the opposed side surfaces of the left and right flange halves Cf1 and Cf2 are abutted. A plurality of bolts B described later are detachably coupled. The left and right flange halves Cf1 and Cf2 are overlapped with each other to form a flange portion Cf on the outer periphery of the differential case C. In the overlapped state, the two flange halves Cf1 and Cf2 are coupled with the ring gear R by a plurality of bolts B. It is tightened together.

  The ring gear R meshes with, for example, a drive gear 8 that serves as an output unit of a transmission connected to the engine. Thereby, the rotational driving force from the drive gear 8 is transmitted to the pinion shaft 21 and the differential case C via the ring gear R.

  Further, in the present embodiment, the ring gear R includes a rim portion Ra having a helical gear-shaped tooth portion Rag on the outer periphery, and a ring plate-like spoke portion Rb protruding integrally from the inner peripheral surface of the rim portion Ra. . The spoke portion Rb is concentrically fitted to an annular step portion 51 provided on the outer surface of the second flange half Cf2, and the fitted state passes through the spoke portion Rb and the second flange half Cf2. It is held by a plurality of bolts B that are screwed into one flange half Cf1 and tightened.

  In FIG. 1, the tooth portion Rag is a cross-sectional display along the tooth trace to simplify the display.

  The differential mechanism 20 is disposed on a second axis X2 orthogonal to the first axis X1 at the center of the differential case C and is supported by the differential case C, and a pair of rotatably supported by the pinion shaft 21. Pinion gears 22, 22 and left and right side gears 23, 23 that mesh with each pinion gear 22 are provided. The left and right side gears 23 and 23 function as output gears of the differential mechanism 20, and the inner ends of the left and right axles 11 and 12 are spline-fitted to the inner peripheral surfaces of the side gears 23 and 23, respectively. .

  The back surfaces of the pinion gear 22 and the side gear 23 are rotatably supported on the inner surface Ci of the differential case C via a pinion washer 25 and a side gear washer 26. The inner surface Ci of the differential case C is exemplified as a spherical surface in the present embodiment, but it may be a tapered surface or a flat surface orthogonal to the first axis X1 or the second axis X2.

  The pinion shaft 21 is inserted into a shaft hole 40 (described later) of the differential case C, and both ends of the pinion shaft 21 are engaged with engagement recesses Rbi provided on the inner peripheral end of the ring gear R (that is, the inner peripheral surface of the spoke Rb). By combining, separation from the shaft hole 40 is prevented.

  Thus, the rotational driving force transmitted from the ring gear R to the differential case C via the flange portion Cf is distributed and transmitted to the left and right axles 11 and 12 through the differential mechanism 20 while allowing differential rotation. Since the power distribution function of the differential mechanism 20 is well known in the art, further explanation is omitted.

  By the way, the first and second case halves C1 and C2 have an annular concave portion 31 and an annular convex portion 32 that are concentrically fitted to each other on the first axis X1, and the case halves C1 and C2 have mating surfaces f1 and f2. Have one and the other.

  In the present embodiment, the open end surface of the first case half C1, that is, the mating surface f1 with the second case half C2, is the end surface of the large diameter end of the main body Cm1 of the first case half C1 and the end surface thereof. The inner surface of the flange half Cf1 that is flush with the first surface is configured as a plane orthogonal to the first axis X1. An annular recess 31 is formed at the radially inner end of the mating surface f1 by being recessed one step from the mating surface f1 to the axially outer side (left side in FIG. 1). Moreover, the annular recess 31 opens not only on the mating surface f1 but also on the inner surface Ci of the differential case C (first case half C1).

  On the other hand, the open end face of the second case half C2, that is, the mating face f2 with the first case half C1, is flush with the end face of the large diameter end of the main body Cm2 of the second case half C2. It is comprised in the plane orthogonal to the 1st axis line X1 by the inner surface of the continuous flange half body Cf2. An annular convex portion 32 is formed at the radially inner end of the mating surface f2 so as to project from the mating surface f2 to the axially outer side (left side in FIG. 1). Moreover, the inner peripheral surface of the annular convex portion 32 constitutes a part of the inner surface Ci of the differential case C (second case half C2).

  The axial front end surface 32t of the annular convex portion 32 and the axially inner bottom surface 31b of the annular concave portion 31 are opposed to each other with a gap in the axial direction. An annular oil groove 34 that opens to the inner surface Ci of the differential case C is formed at a position spaced apart from the pinion shaft 21 in the axial direction by the opposing surfaces.

  Further, a shaft hole 40 into which the pinion shaft 21 is inserted is formed between the mating surfaces f1, f2 of the first and second case halves C1, C2. As clearly shown in FIG. 7, the shaft hole 40 includes a groove portion 43 having a U-shaped cross section that is recessed to receive the pinion shaft 21 on the mating surface f <b> 2 on the second case half C <b> 2 side, and a groove portion 43. And a mating surface f1 on the first case half C1 side, which is a flat surface that closes the open surface.

  Further, in this embodiment, as shown in FIGS. 6 and 7, a clearance 41 b between the shaft hole 40 and the pinion shaft 21 that allows some movement of at least the axial direction of the pinion shaft 21 in the shaft hole 40. Is provided. It is also possible to set such that the play 41b is not provided.

  A semi-cylindrical boss portion 44 covering the back surface side with a sufficient thickness corresponding to the groove portion 43 is integrally provided on the outer side surface of the second case half C2. The boss portion 44 ends at the root portion of the flange half body Cf2. The flange half body Cf2 has a radially outer side opened to a portion connected to the radially outer end of the boss portion 44 (and thus the groove portion 43). A notch 52 is formed. The notch 52 exposes the outer peripheral surfaces of both ends of the pinion shaft 21 to the outside of the differential case C.

  And since the groove part 43 which forms the shaft hole 40 is a U-shaped cross section, and the mating surface f1 is a plane, between the inner surface of the shaft hole 40 and the outer peripheral surface of the pinion shaft 21, FIG. A gap space 41 is formed that extends along the pinion shaft 21 as shown (that is, in the radial direction of the differential case C). The gap space 41 includes a pair of corner-corresponding space portions 41a formed corresponding to both flat inner side surfaces of the groove portion 43 and the plane of the mating surface f1 orthogonal thereto, and the above-described axial clearance. 41b.

  The gap space 41 functions as an oil passage whose end on the radially inner side communicates with the oil groove 34 and whose end on the radially outer side opens to the outside of the differential case C.

  Further, as described above, in order to allow the end portion on the radially inner side of the gap space 41 to communicate with the oil groove 34, the annular convex portion 32 is partially cut away in the circumferential direction at a portion corresponding to the pinion shaft 21. . That is, the notch 32k of the annular protrusion 32 communicates the gap space 41 and the oil groove 34 through this. The notch 32k may be integrally formed with the second case half C2, or may be formed by post-processing after the second case half C2.

  As shown in FIG. 5, the pinion support surface Cip that supports the back surface of the pinion gear 22 through the pinion washer 25 around the second axis X <b> 2 is formed in a slightly concave shape on the inner surface Ci forming the spherical shape of the differential case C. Has been. And the opening part of the oil groove 34 is arrange | positioned in the axial direction outer side rather than the contact surface 54 with the pinion washer 25 of the pinion support surface Cip (refer FIG. 6).

  Next, the operation of the embodiment will be described.

  The first and second case halves C1 and C2 of the differential case C are integrally formed of a metal material (for example, aluminum, aluminum alloy, cast iron, etc.) (for example, forging or casting), and after the forming, the first half The parts of the first and second case halves C1 and C2 are machined to finish the final form of the product (first and second case halves C1 and C2).

  When assembling the differential device D, the first and second case halves C1 and C2 are separated from each other, and each component of the differential mechanism 20, that is, the pinion shaft 21, the pinion gear 22, and the side gear 23 is interposed therebetween. , The mating surfaces f1, f2 of the first and second case halves C1, C2 are butted together. At that time, the case halves C1 and C2 are correctly arranged concentrically by fitting the annular concave portions 31 and the annular convex portions 32 of the mating surfaces f1 and f2.

  Next, the inner peripheral end portion of the spoke portion Rb of the ring gear R is concentrically fitted to the annular step portion 51 on the side surface of the second case half C2, and the ring gear R and the flange halves Cf1 and Cf2 are fastened together with a plurality of bolts B. . In this co-tightened state, the ring gear R is prevented from coming out from the shaft hole 40 of the pinion shaft 21 by engaging engagement recesses Rbi on the inner periphery of the spoke portion Rb with both ends of the pinion shaft 21. And the pinion shaft 21 are connected so that torque can be directly transmitted.

  The first and second bearing bosses Cb1 and Cb2 of the differential case C housing the differential mechanism 20 are rotatably supported by the transmission case 9 via bearings 13 and 14, and the inner end portions of the left and right axles 11 and 12 are further supported. Is inserted into the first and second bearing bosses Cb1 and Cb2 and fitted to the inner circumferences of the left and right side gears 23 and 23 to complete the assembly of the differential device D to the automobile.

  When the differential device D performs a differential function, the left and right bearing bosses Cb1 and Cb2 of the differential case C and the axles 11 and 12 rotate relative to each other, and accordingly, the spiral grooves 15 and 16 on the inner periphery of the bearing bosses Cb1 and Cb2 Exerts a screw pump action for feeding the lubricating oil in the transmission case 9 into the differential case C. Thereby, even if there is no window hole in the differential case C, the lubricating oil outside the differential case C can be sufficiently introduced into the differential mechanism 20 in the differential case C.

  By the way, a part of the lubricating oil introduced into the differential case C and lubricated each part of the differential mechanism 20 is caused by centrifugal force, and the annular recesses 31 that are concentrically fitted to the mating surfaces f1, f2 of the first and second case halves C1, C2. And flows into the annular oil groove 34 between the axially opposed surfaces of the annular protrusion 32. The inflowing lubricating oil flows in the annular oil groove 34 in the circumferential direction, and in the shaft hole 40 formed between the mating surfaces f1 and f2 from the notch 32k of the annular protrusion 32 as illustrated by the arrow a in FIG. The gap space 41 is reached. Then, the reached lubricating oil further flows through the clearance space 41 in the shaft hole 40 radially outward by the action of centrifugal force, and is smoothly discharged out of the differential case C from the radially outward end. Is done.

  Accordingly, the lubricating oil in the differential case C can be smoothly discharged out of the differential case C without specially providing a large window hole in the differential case C, and the oil for lubricating the differential mechanism 20 can be efficiently distributed and replaced inside and outside the differential case C. Therefore, the lubrication function of each part of the differential mechanism 20 can be satisfactorily exhibited, which can contribute to prevention of seizure of each part of the differential mechanism 20. Also, if the wear metal powder generated by the gear engagement of the differential mechanism 20 remains without being discharged out of the differential case C together with the lubricating oil, abnormal noise is generated from each part of the differential mechanism 20 and the durability of the differential mechanism 20 is reduced. However, in this embodiment, since the lubricating oil can be efficiently circulated and exchanged inside and outside the differential case C as described above, a large amount of metal wear powder remains in the differential case C. This prevents the differential mechanism 20 from operating smoothly and improves durability.

  In addition, the clearance groove 41 in the oil groove 34 and the shaft hole 40 serving as a lubricating oil discharge path to the outside of the differential case C is a clearance between the mating surfaces f1 and f2 between the first and second case halves C1 and C2. Therefore, it is possible to simplify the structure for discharging the lubricating oil in the differential case C. Therefore, it is not necessary to add a large window hole to the differential case C, so that cost saving is achieved. When the first and second case halves C1 and C2 are forged, the window hole is not required to be formed, so that the structure of the forging die is simplified and the cost can be further reduced. .

  In the present embodiment, the annular convex portion 32 provided on the mating surface f2 of the second case half C2 with the first case half C1 is partially cut away in the circumferential direction at a portion corresponding to the pinion shaft 21. Thus, the gap space 41 and the oil groove 34 communicate with each other through the notch 32k. Thereby, since it is possible to communicate between the oil groove 34 and the gap space 41 (oil passage) in the shaft hole 40 with a simple communication structure in which the annular protrusion 32 is partially cut away in the circumferential direction, Further structural simplification and thus cost savings are achieved.

  Further, on the inner surface Ci of the differential case C of the present embodiment, a pinion support surface Cip that rotatably supports the rear surface Ci of the pinion gear 22 via the pinion washer 25 is formed to be slightly concave from the inner surface Ci. The opening to the inner surface Ci of the differential case is disposed on the axially outer side of the contact surface 54 of the pinion support surface Cip with the pinion washer 25.

  As a result, even if a gap space 41 serving as an oil passage is formed in the shaft hole 40 or a notch 32k is provided in the annular convex portion 32 in order to connect the gap space 41 and the oil groove 34, these gap spaces The opening on the radially inner end side of 41 and the notch 32k is entirely or largely blocked by the back of the pinion washer 25 and the pinion gear 22 during transmission. Moreover, since the opening position of the oil groove 34 can be sufficiently offset in the axially outward direction with respect to the pinion washer abutment surface 54 of the pinion washer 25 or the pinion support surface Cip, the maximum diameter portion (that is, the pinion) of the differential case inner surface Ci Lubricating oil can be easily accumulated in the entire peripheral region including the corresponding portions of the shaft 21 and the pinion gear 22, that is, the amount of lubricating oil flowing out from the maximum diameter portion toward the oil groove 34 or the gap space 41 is suppressed. As a result, each part of the pinion gear 22 (for example, a tooth part, a back surface, a pinion shaft fitting part, etc.) can be efficiently lubricated.

  Further, the mating surface f1 of the first case half C1 of the present embodiment with respect to the second case half C2 is formed on a plane orthogonal to the first axis X1, and the first case half of the second case half C2 is formed. A groove 43 having a U-shaped cross section that forms a shaft hole 40 in cooperation with the flat surface of the mating surface f1 is recessed in the mating surface f2 with C1. As a result, the first case half C1 can be flattened at its mating surface f1, thereby simplifying the structure and facilitating processing. Also, with respect to the mating surface f2 of the second case half C2, since the pinion shaft 21 is fixed by the ring gear R and is not brought into contact with the differential case C, only a U-shaped groove is required to obtain the shaft hole 40. No drilling or special shape grooving is required. As a result, the machining process is easy and cost saving is achieved. This effect is advantageous in terms of cost especially when the second case half C2 is forged.

  Further, the first and second case halves C1 and C2 of the present embodiment integrally have first and second flange halves Cf1 and Cf2 that are overlapped with each other to form the flange portion Cf, respectively, at the outer peripheral end portions. The first and second flange halves Cf1 and Cf2 and the spoke portion Rb of the ring gear R are fastened by a common bolt B, and both end portions of the pinion shaft 21 are connected to the inner peripheral portion (engagement recess Rbi) of the spoke portion Rb. Are engaged with the concave and convex portions so that torque can be transmitted.

  Thereby, even if the differential case C is divided into two, the case halves C1 and C2 and the ring gear R can be fastened with a simple coupling structure. In addition, the point that the rotational torque can be directly transmitted from the ring gear R to the pinion shaft 21 side and the point that the pinion shaft 21 is floatingly supported in the shaft hole 40 with some play 41b in the axial direction are combined. It is possible to reduce the load burden on the individual case halves C1 and C2 during transmission. This effect is particularly advantageous when the case halves C1 and C2 are formed of a relatively low-rigidity material (for example, aluminum or aluminum alloy).

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment, A various design change is possible in the range which does not deviate from the summary.

  For example, in the above embodiment, the differential device D is implemented as a vehicle differential device. However, in the present invention, the differential device D may be implemented in various mechanical devices other than the vehicle.

  In the above embodiment, the coupling between the flange portion Cf of the differential case C and the ring gear R is exemplified by a plurality of bolts B. However, in the present invention, the coupling between the flange portion Cf and the ring gear R is welded (for example, (Laser welding, electron beam welding, etc.).

  In the above-described embodiment, the tooth portion Rag of the ring gear R has a helical gear shape. However, the ring gear of the present invention is not limited to the embodiment, and may be a bevel gear, a hypoid gear, a spur gear, or the like.

  In the above embodiment, the shaft hole 40 is formed by the mating surface f1 (plane) of one case half C1 and the groove 43 of the mating surface f2 of the other case half C2. A groove part facing the groove part 43 may also be provided on the f1 side so that the shaft hole 40 is formed between the groove parts of the mating surfaces f1 and f2.

  In the above-described embodiment, the spiral grooves 15 and 16 for drawing the lubricating oil provided on the inner peripheral surfaces of the bearing bosses Cb1 and Cb2 are shown as an example of the lubricating oil introducing means. However, the lubricating oil introducing means is limited to the embodiment. Not. For example, instead of or in addition to the spiral grooves 15 and 16, the axles 11 and 12, a lubricating oil path that serves as a lubricating oil introduction means on the side gear boss that extends long on the back surface of the side gear 23 and extends outside the differential case C, A spiral groove may be provided. Alternatively, means for injecting or dripping the lubricating oil from the ceiling or side wall of the transmission case 9 toward the outer end opening (gap space 41) of the shaft hole 40 may be used as the lubricating oil introduction means.

  Moreover, in the said embodiment, what used the circumferential notch 32k provided in the cyclic | annular convex part 32 as a communication means which connects between the oil groove 34 and the clearance gap 41 in the shaft hole 40 was shown. However, the communication means is not limited to the embodiment. For example, the oil groove 34 and the gap space 41 may be communicated with each other through a communication hole provided in the first or second case half C1 (C2).

  Moreover, in the said embodiment, although the annular recessed part 31 and the annular convex part 32 were continuous in the circumferential direction, the shape of these annular recessed part 31 and the annular convex part 32 is not limited to embodiment, For example, a discontinuous part is formed. An annular concave part and an annular convex part may be included.

C ··· Differential case C1 ··· First case half (one case half)
C2 ... Second case half (the other case half)
Cf: Flange Ci: Inner surface Cip of differential case ... Pinion support surface D ... Differential gear f1, f2 ... Mating surface R ... Ring gear Rag ... tooth part X1, X2 ... first and second axis 8 ... drive gears 15, 16 ... spiral groove (lubricant introduction means)
20... Differential mechanism 21... Pinion shaft 22... Pinion gear 23... Side gear 25... Pinion washer 31. ··· Round convex portion 32k ··· notch portion 34 ··· oil groove 40 ··· shaft hole 41 ··· clearance space 43 ··· groove portion 54 ··· pinion Contact surface of the support surface with the pinion washer

Claims (4)

A hollow differential case (C) rotatable around the first axis (X1);
A differential mechanism (20) housed in the differential case (C);
Lubricating oil introduction means (15, 16) capable of introducing lubricating oil from the outside into the differential case (C);
A ring gear (R) that is coupled to a flange (Cf) on the outer periphery of the differential case (C) and meshes with a drive gear (8) connected to a power source;
The differential mechanism (20) includes a pinion shaft (21) disposed on a second axis (X2) orthogonal to the first axis (X1) and supported by the differential case (C), and the pinion shaft (21 ) And a pair of side gears (23) meshed with the pinion gear (22) and rotatable about the first axis (X1).
The differential case (C) includes a pair of case halves (C1, C2) that are coupled to each other with each open end face as a mating surface (f1, f2). The pair of case halves (C1, C2) An annular concave portion (31) and an annular convex portion (32), which are concentrically fitted to each other on the first axis (X1), are provided on one and the other of the mating surfaces (f1, f2)
The tip surface (32t) of the annular convex portion (32) and the inner bottom surface (31b) of the annular concave portion (31) are opposed to each other with a gap in the axial direction. An oil groove (34) that opens to the inner surface (Ci) of the differential case (C) is formed at a position spaced apart from the shaft (21) in the axial direction,
A shaft hole (40) into which the pinion shaft (21) is inserted is formed between the mating surfaces (f1, f2).
Between the shaft hole (40) and the pinion shaft (21), the radially inner end communicates with the oil groove (34) and the radially outer end is the differential case ( A differential device characterized in that a gap space (41) serving as an oil passage communicating with the outside of C) is interposed.   The annular convex portion (32) is partially cut in the circumferential direction at a portion corresponding to the pinion shaft (21), and the oil groove (34) and the gap space ( 41. The differential device according to claim 1, wherein 41) communicates with the differential device. On the inner surface (Ci) of the differential case (C), a pinion support surface (Cip) for rotatably supporting the back surface of the pinion gear (22) via a pinion washer (25) is formed in a concave shape,
The opening of the oil groove (34) to the inner surface (Ci) of the differential case (C) is more axial than the contact surface (54) of the pinion support surface (Cip) with the pinion washer (25). The differential device according to claim 2, wherein the differential device is arranged on an outer side in the direction. A mating surface (f1) of one case half (C1) having the annular recess (31) with respect to the other case half (C2) is formed on a plane orthogonal to the first axis (X1),
A cross-sectional U-shape that forms the shaft hole (40) in cooperation with the plane on the mating surface (f2) of the other case half (C2) with the one case half (C1) The differential device according to claim 1, wherein the groove portion (43) is recessed.

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