JP2014190374A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device capable of surely maintaining sufficient lubricating state of a sliding part between a pinion shaft and differential pinion.SOLUTION: An oil introduction flow passage 12 for introducing lubricating oil supplied from the outside to the inside of an axle insertion hole 13 along a radial direction is formed on end surfaces of a pair of boss parts 11, a side gear oil guide flow passage for guiding the lubricating oil from the axle insertion hole to a pinion shaft 3 is formed in spline holes 31 of a pair of a differential side gears 5, and a gear oil reservoir 23 for collecting and accumulating the lubricating oil is formed in an inner end surface position of a confronting part of the pinion shaft and a pair of differential pinions 4.

Description

  The present invention relates to a differential device that transmits a driving force of a prime mover such as an engine or a motor to a wheel drive shaft, and in particular, lubricity of a sliding portion between a pinion shaft and a differential pinion rotatably supported by the pinion shaft. The present invention relates to a differential apparatus suitable for improvement.

  Conventionally, in a vehicle such as a three-wheel or four-wheel vehicle, when a vehicle turns, the driving of a prime mover such as an engine or a motor can be performed without causing any one of the left and right wheel drive shafts to slip. It is known to transmit force to the left and right wheel drive shafts via a differential device.

  Such a conventional differential device includes a differential case that is rotationally driven, a pinion shaft that is mounted in the differential scale and rotates integrally with the differential case, and a plurality of, for example, 1 rotatably supported at both ends of the pinion shaft. A pair of differential pinions and a pair of differential side gears that are rotatably accommodated in the differential case while being engaged with the respective differential pinions are provided. A pair of bosses formed in a cylindrical shape are formed on both end sides along the rotation axis of the differential case. The inner peripheral surfaces of these boss portions are axle insertion holes that rotatably support one end sides of the left and right wheel drive shafts inserted into the differential case. The pinion shaft is attached to the differential case with its axial direction oriented in a direction orthogonal to the rotational axis of the differential case. Further, each of the pair of differential pinions revolves around the rotation axis of the differential case and rotates around the axis of the pinion shaft when the differential case rotates. Furthermore, the pair of differential side gears are arranged coaxially with the rotation axis of the differential case and opposed to the inside of the differential case, and for spline coupling one end of the left and right wheel drive shafts along the rotation axis. A spline hole having a plurality of spline teeth is formed (see, for example, Patent Document 1).

  By the way, in the conventional differential device, it is known that insufficient lubrication oil supply occurs in the sliding portion between the pinion shaft and the differential pinion, and as a result, seizure occurs in the sliding portion between the pinion shaft and the differential pinion. Yes.

  In order to cope with such a problem, a part of a plurality of spline teeth formed in the spline hole of the differential side gear, for example, three teeth are missing, and a side gear oil guide passage is provided, thereby providing a pinion shaft. A differential device has been proposed in which the amount of lubricating oil supplied to the sliding portion between the pinion shaft and the differential pinion is increased to improve the lubricity of the sliding portion between the pinion shaft and the differential pinion (see, for example, Patent Document 2).

  Further, in order to cope with the above-mentioned problems, the applicant of the present application is an oil pocket capable of capturing and storing lubricating oil on the inner end face (end face of the pinion revolution axis) of the sliding portion between the pinion shaft and the differential pinion. The differential apparatus which improved the lubricity of the sliding part of a pinion shaft and a differential pinion by providing is proposed (for example, refer patent document 3).

JP-A-52-170173 JP-A-8-170717 JP 2004-360807 A

  However, in the conventional differential device, the amount of lubricating oil supplied to the sliding portion between the pinion shaft and the differential pinion is insufficient and the lubricating state is deteriorated, and the good lubricating state of the sliding portion cannot be reliably maintained. There was a problem that there was a case.

  The present invention has been made in view of these points, and an object of the present invention is to provide a differential device that can reliably maintain a good lubrication state of a sliding portion between a pinion shaft and a differential pinion.

  In order to achieve the above-described object, the differential device of the present invention is rotationally driven, and the inner and outer sides of the inner peripheral surface communicate with one end side of the left and right wheel drive shafts at both end sides along the rotation axis. A differential case in which a pair of cylindrical bosses formed as axle insertion holes are formed, and is attached to the differential case and rotates integrally with the differential case, and its axial direction is the rotational axis of the differential case A pinion shaft arranged in a direction orthogonal to the pinion shaft, and rotatably supported at both ends of the pinion shaft, and can revolve around the rotation axis of the differential case, and the axis of the pinion shaft A pair of differential pinions that are capable of rotating about the center, and the inside of the differential case coaxially with the rotational axis of the differential case A spline hole, which is opposed to each other in a state of being meshed with each of the pair of differential pinions, and has a plurality of spline teeth for spline coupling one end of each of the left and right wheel drive shafts, extends along the rotation axis. A differential gear having a pair of differential side gears formed on the tip end surfaces of the pair of boss portions, the lubricating oil supplied from the outside along the radial direction. An oil introduction passage for introduction into the axle insertion hole is formed, and a side gear that guides the lubricating oil from the axle insertion hole toward the pinion shaft in each spline hole of the pair of differential side gears An oil guide passage is formed, and lubricating oil is applied to the inner end face position of the opposed portion of the pinion shaft and the pair of differential pinions. It is characterized in that 捉 to reservoir oil for storable gear is formed.

  And by adopting such a configuration, the oil introduction flow path formed on the tip surface of the boss portion can flow the lubricating oil supplied from the outside to the axle insertion hole when the differential case rotates. The amount of lubricating oil supplied from the outside to the inside of the differential case can be increased compared to the conventional case. In addition, the side gear oil guide passage formed in the spline hole can guide the lubricating oil from the axle insertion hole toward the pinion shaft without impairing the coupling strength between the differential side gear and the wheel drive shaft by the spline. Since the flow passage area can be easily and reliably increased, the amount of lubricating oil supplied from the axle insertion hole through the inside of the spline hole to the pinion shaft can be increased as compared with the prior art. Furthermore, the oil sump for the gear formed on the pinion shaft can increase the capacity of the lubricating oil to be captured and stored in the sump for gear without reducing the strength of the pinion shaft and the differential pinion as compared with the conventional case. When the differential case rotates, the stored lubricating oil can be efficiently introduced from the entire circumference of the pinion shaft into the sliding portion between the pinion shaft and the differential pinion. As a result, the amount of lubricating oil supplied to the sliding portion between the pinion shaft and the differential pinion is simpler and more reliable than before with a simple configuration of providing an oil introduction channel, an oil guide channel for side gears, and an oil reservoir for gears. Therefore, it is possible to reliably maintain a good lubrication state of the sliding portion between the pinion shaft and the differential pinion.

  In the present invention, the oil introduction flow path is formed by a plurality of oil introduction grooves that communicate the inside and outside of the tip surface of the boss portion, and the side gear oil guide flow path is the pair of differential side gears. A plurality of spline teeth formed in the respective spline holes are formed as missing teeth, and the oil sump for gears is formed by the pair of differential pinions on the outer peripheral surface of the pinion shaft. The diameter of the oil retaining annular groove formed at the position of the inner end surface of the opposed portion facing each other and the axially outer diameter formed at the inner end of each inner hole of the pair of differential pinions is increased. It can be set as the structure currently formed by the cyclic | annular enlarged diameter part. And by employ | adopting such a structure, the some oil introduction groove | channel can form an oil introduction flow path easily. Further, the missing tooth can easily form the side gear oil guiding channel, and the number of teeth of the missing tooth can be easily increased to increase the channel area of the side gear oil guiding channel. Furthermore, the oil retaining annular groove and the annular diameter-enlarged portion can easily form a gear oil reservoir, and can easily increase the capacity of the lubricating oil that is captured and stored in the gear oil reservoir. Therefore, since the supply amount of the lubricating oil to the sliding portion between the pinion shaft and the differential pinion can be easily increased, the good lubricating state of the sliding portion between the pinion shaft and the differential pinion can be more reliably maintained. .

  Furthermore, in this invention, when the number of teeth of the said spline teeth is 27, it can be set as the structure whose number of teeth made into the said missing tooth is 5 teeth. And by adopting such a configuration, it passes through the oil guide passage for side gear that guides the lubricating oil from the axle insertion hole toward the pinion shaft without impairing the coupling strength between the differential side gear and the wheel drive shaft by the spline. The amount of lubricating oil to be supplied can be reliably prevented from consuming the lubricating oil held in the gear oil sump. As a result, a good lubrication state of the sliding portion between the pinion shaft and the differential pinion can be more reliably maintained.

  Furthermore, in the present invention, in each of the pair of axle insertion holes, the lubricating oil supplied to the axle insertion hole via the oil introduction passage is brought into the inside of the differential case along with the rotation of the differential case. An oil guide channel for case that guides toward the vehicle is formed, and one end of the oil guide channel for case can be connected to the oil introduction channel. By adopting such a configuration, the lubricating oil supplied to the axle insertion hole via the oil introduction passage can be easily and reliably flowed toward the inside of the differential case as the differential case rotates. .

  According to the differential device of the present invention, the amount of lubricating oil supplied to the sliding portion between the pinion shaft and the differential pinion can be reduced with a simple configuration of providing an oil introduction passage, a side gear oil guide passage, and a gear oil sump. Since it can increase easily and reliably compared with the past, it has the outstanding effect that the favorable lubrication state of the sliding part of a pinion shaft and a differential pinion can be hold | maintained reliably.

Sectional drawing which shows the principal part of embodiment of the differential apparatus which concerns on this invention The side view which shows the front end surface of the bearing mounting part of the right side of FIG. Enlarged view showing the vicinity of the gear oil sump in FIG. The expanded sectional view which shows the coupling | bond part of the spline hole of the differential side gear of FIG. 1, and the spline shaft of a wheel drive shaft.

  The present invention will be described below with reference to embodiments shown in the drawings.

  As shown in FIG. 1, the differential device 1 of the present embodiment includes a differential case 2 that is rotationally driven, a pinion shaft 3 that is attached in the differential case 2 and rotates integrally with the differential case 2, and both end portions of the pinion shaft 3. And a pair of differential side gears 5 rotatably accommodated in the differential case 2 in mesh with the respective differential pinions 4. .

  The differential case 2 is arranged so that the rotation axis C1 (hereinafter referred to as the differential axis C1) is substantially horizontal when mounted on the vehicle. A pair of boss portions 11 formed in a cylindrical shape are formed on both end sides along the differential axis C1. A plurality of, in this embodiment, two oil introduction grooves 12 a that communicate the boss parts 11 in the thickness direction are formed on the front end surfaces of both the boss parts 11, and these oil introduction grooves 12 a are formed. Thus, an oil introduction passage 12 for introducing the lubricating oil supplied from the outside of the present embodiment into the inside of an axle insertion hole 13 described later along the radial direction is formed. 2 shows the oil introduction channel 12 formed on the front end surface of the right boss portion 11. As shown in FIG. Further, the number, shape, and size of the oil introduction groove 12a can be set according to the design concept and the like. For example, the oil introduction groove 12a can be formed at 3, 4, 5,.

  The bottom surface 12aa of the oil introduction groove 12a is formed such that the radially outer side is inclined toward the inner diameter side which is higher than the radially inner side. Further, as shown in FIG. 2, the side surface shape of the oil introduction groove 12a is a shape that can capture the lubricating oil supplied from the outside during rotation of the differential case 2 and flow it into the inside, that is, scrape the lubricating oil. It is formed to be able to. In the present embodiment, during rotation of the differential case 2 indicated by the arc-shaped arrow in FIG. 2, the side surface located on the leading side in the rotational direction of the differential case 2 is the outer edge of the boss portion 11 is the inner edge of the boss portion 11. The inclined surface 12ab is inclined by being arranged on the leading side in the rotational direction of the differential case 2 from the edge on the circumferential side.

  Each inner peripheral surface of the pair of boss portions 11 is an axle insertion hole 13 that rotatably supports one end side of the left and right wheel drive shafts S inserted into the differential case 2. Furthermore, a case oil groove 14 a is formed on the inner peripheral surface of each of the boss portions 11 so as to be spirally bored toward the inside of the differential case 2. One end of the case oil groove 14a on the outer side in the differential axial direction is recessed at the bottom surface 12aa of the oil introduction groove 12a, in the present embodiment, on the inner peripheral side of the bottom surface 12aa and adjacent to the inclined surface 12ab. It is connected to the oil sump 12ac for introduction. Further, the case oil groove 14 a formed in the right axle insertion hole 13 and the case oil groove 14 a formed in the left axle insertion hole 13 are formed on the differential axis C <b> 1 provided in the center portion of the differential case 2. It is formed in plane symmetry via a virtual symmetry plane (not shown) including an axis C2 (hereinafter referred to as shaft axis C2) perpendicular to the axis.

  A bearing mounting portion 15 on which a bearing for rotatably supporting the differential case 2 in a housing such as a transmission case (not shown) is formed on the distal end side of the outer peripheral surface of the pair of boss portions 11.

  The case oil guide channel 14 for causing the lubricating oil supplied to the axle insertion hole 13 through the oil introduction channel 12 of the present embodiment to flow toward the inside of the differential case 2 by the case oil groove 14a. It is configured. Note that the lubricating oil supplied to the axle insertion hole 13 via the oil introduction flow path 12 is directed toward the inside of the differential case 2 by a gap between the axle insertion hole 13 and the wheel drive shaft S inserted therein. Although it can be made to flow, it is preferable to provide the case oil guide channel 14 in the sense that the flow is easily and reliably caused by the rotation of the differential case 2. For this reason, it is important to form the lubricating oil flow in the spiral direction of the case oil groove 14a toward the inside of the differential case 2 as the differential case 2 rotates.

  Returning to FIG. 1, the pinion shaft 3 is formed in a cylindrical shape as a whole, and both end portions thereof are fitted into a pair of through holes formed so as to penetrate in the direction of the shaft axis C <b> 2. That is, the axis of the pinion shaft 3 is formed coaxially with the shaft axis C2 of the differential case 2. Therefore, the pinion shaft 3 rotates about the differential axis C1 together with the differential case 2 when the differential case 2 rotates about the differential axis C1. Further, concentric through holes 17 and 18 perpendicular to the shaft axis C2 are formed in one end portion of the pinion shaft 3 and the differential case 2, respectively. The pinion shaft 3 is fitted into the through holes 17 and 18 by press fitting or the like. The pin 19 is attached so as not to come out of the differential case 2. Most of the lubricating oil supplied to the inside of the differential case 2 passes through a window portion (not shown) used for assembling the pinion shaft 3, the differential pinion 4, and the differential side gear 5 to the inside of the differential case 2 formed in the differential case 2. To be discharged to the outside. Further, the remaining part (a small part) of the lubricating oil supplied to the inside of the differential case 2 is discharged to the outside through a gap between the opposing surfaces of the differential case 2 and the pinion shaft 3.

  Two flat portions 3 a extending in parallel with each other are formed on the opposing portion of the outer peripheral surface of the pinion shaft 3 facing the pair of differential pinions 4. Further, as shown in an exaggerated manner in FIG. 3, an oil retaining annular groove 21 is formed at the position of the inner end surface (difference axis line side) of the opposing portion of the pinion shaft 3 and the differential pinion 4. The outer end face of the oil retaining annular groove 21 is connected to the inner end face of the flat surface portion 3 a, and the position of the inner end face of the differential pinion 4 is arranged at an intermediate position in the axial direction of the oil retaining annular groove 21. Yes.

  Returning to FIG. 1, the pair of differential pinions 4 is housed in a state of being inserted into the pinion shaft 3 inside the differential case 2, and is configured by a pair of bevel gears arranged to face each other on the shaft axis C <b> 2. ing. The pair of differential pinions 4 is supported by the pinion shaft 3 so as to be relatively rotatable about the shaft axis C2, and the differential case 2 and the pinion shaft 3 are rotated about the differential axis C1 to thereby center the differential axis C1 together. It is supposed to rotate as. In other words, the pair of differential pinions 4 can revolve around the differential axis C1 and can rotate about the shaft axis C2. Further, as exaggeratedly shown in FIG. 3, an annular enlarged portion 22 that increases in diameter toward the outside in the axial direction is formed at the inner end of each inner hole of the pair of differential pinions 4. As the annular enlarged diameter portion 22, the lubricating oil supplied to the outer peripheral surface of the pinion shaft 3 is rotated around the differential axis C 1 of the pinion shaft 3 as the differential case 2 rotates, and the differential pinion is centered on the shaft axis C 2. It is preferable to have a shape that can prevent scattering to the outer periphery due to the centrifugal force during rotation. For this reason, the annular enlarged diameter portion 22 in the present embodiment is formed by providing a chamfer having a slope with an angle of about 10 ° at the inner end of the inner hole of the differential pinion 4. The pinion shaft 3 can be Y-shaped and the number of differential pinions 4 can be three, or the pinion shaft 3 can be cross-shaped and the number of differential pinions 4 can be four.

  The oil retaining annular groove 21 and the annular enlarged diameter portion 22 constitute a gear oil reservoir 23 in the present embodiment capable of capturing and storing lubricating oil. In addition, what is necessary is just to set the magnitude | size and shape of the annular groove | channel 21 for oil holding | maintenance, and the annular enlarged diameter part 22 as needed, such as a design concept.

  Returning to FIG. 1, the pair of differential side gears 5 is constituted by a pair of bevel gears arranged to face each other in a state of meshing with each of the pair of differential pinions 4 on the differential axis C <b> 1. The pair of differential side gears 5 rotate about the differential axis C1 by rotating the differential case 2, the pinion shaft 3, and the pair of differential pinions 4 about the differential axis C1.

  As shown in FIG. 4, each of the pair of differential side gears 5 is provided with a plurality of spline teeth 31a (only a part of FIG. A spline hole 31 is formed along the differential axis C1. Further, a part of the plurality of spline teeth 31a is missing, and the missing tooth portion forms a side gear oil guiding passage 33 that guides lubricating oil from the axle insertion hole 13 toward the pinion shaft 3. Has been. Note that the number of teeth to be missing (the location where the missing tooth portion of the plurality of spline teeth 31a is formed) depends on the size of the wheel drive shaft S, the number of teeth of the differential pinion 4 and the differential side gear 5, and the module. 4 or 5 teeth (4 or 5 places) is supplied to the sliding portion in the differential case 2 when the differential case 2 rotates without impairing the coupling strength between the differential side gear 5 and the wheel drive shaft S by the spline. This is preferable in the sense that the supply amount of the lubricating oil can be made appropriate. In the present embodiment, the number of spline teeth 31a is 27 and the number of missing teeth is 5 (five places), so that the number of the side gear oil guide channels 33 is five.

  Here, as for the position of the missing tooth, it is arranged so that the distance between the centers of the two missing teeth adjacent to each other is as equal as possible. It is preferable in the sense that it can be arranged.

  The lubricating oil supplied to the inside of the differential case 2 is slid inside the transmission by, for example, forced oiling using an oil pump driven by the driving force of the driving force transmission device or splashing oil using splashes of lubricating oil. Lubricating oil supplied to the moving part is used.

  Since other configurations are the same as those of a conventionally known differential device, detailed description thereof is omitted.

  Next, the operation of the present embodiment having the above-described configuration will be described.

  According to the differential device 1 of the present embodiment, the lubricating oil supplied from the outside of the differential case 2 when the differential case 2 rotates is captured by the oil introduction groove 12 a as the oil introduction channel 12 by the rotation of the differential case 2. The lubricating oil captured by the oil introduction groove 12a flows from the outside toward the inside along the inclination of the bottom surface 12aa of the oil introduction groove 12a, and from the outer peripheral side of the boss portion 11 to the inside along the inclined surface 12ab. The lubricating oil accumulated in the introduction oil reservoir 12ac is supplied to the case oil groove 14a connected to the introduction oil reservoir 12ac.

  Next, the lubricating oil that has flowed into the case oil groove 14 a flows into the axle insertion hole 13, and the lubricating oil that has flowed into the axle insertion hole 13 flows toward the center of the differential case 2 due to the rotation of the differential case 2.

  Next, the lubricating oil flowing in the case oil groove 14 a toward the center of the differential case 2 is caused by the side gear oil guide passage 33 formed in the spline hole 31 of the pair of differential side gears 5 by the rotation of the differential case 2. , It flows toward the portion located between the pair of differential pinions 4 in the outer peripheral surface of the pinion shaft 3 and is supplied to the outer peripheral surface of the pinion shaft 3.

  Next, the lubricating oil supplied to the outer peripheral surface of the pinion shaft 3 causes the surface of the pinion shaft 3 to face the end of the pinion shaft 3 by rotation about the differential axis C1 of the pinion shaft 3 as the differential case 2 rotates. Fluid. At this time, the lubricating oil is trapped in the gear oil sump 23 including the oil retaining annular groove 21 and the annular enlarged diameter portion 22 while flowing on the surface of the pinion shaft 3 toward the end of the pinion shaft 3. As a result, the lubricating oil is stored (supplied) in the gear oil reservoir 23. The lubricating oil stored in the oil sump 23 flows into the sliding portion between the pinion shaft 3 and the differential pinion 4 due to the centrifugal force generated by the rotation about the differential axis C of the pinion shaft 3 as the differential case 2 rotates. Thus, a lubricating oil film is formed on the sliding portion, and the sliding portion is properly maintained in lubrication.

  Next, the lubricating oil after lubrication of the sliding portion between the pinion shaft 3 and the differential pinion 4 passes between the opposing surfaces of the pinion shaft 3 and the differential pinion 4 by rotation about the differential axis C1 of the pinion shaft 3. Then, it is discharged to the outside through the window portion of the differential case 2.

  A portion of the lubricating oil trapped in the gear oil reservoir 23 that exceeds the flow amount to the sliding portion is sequentially stored in the gear oil reservoir 23. When the lubricating oil stored in the gear oil reservoir 23 exceeds the capacity of the space that forms the gear oil reservoir 23, the excess lubricating oil is rotated by the rotation (rotation) of the differential pinion 4 and the inner end surface of the differential pinion 4 Along the diffusive case 2, splashed and scattered in the differential case 2, and used for lubrication of the meshing part of the differential pinion 4 and the differential side gear 5. After being used for lubrication of the sliding portion, it is discharged to the outside through a window portion or the like.

  As described above, according to the differential device 1 of the present embodiment, the oil introduction flow path 12 formed on the front end surface of the boss portion 11 has conventionally used the lubricating oil supplied from the outside without reducing the strength of the differential case 2. Therefore, the amount of lubricating oil supplied from the outside to the inside of the differential case 2 can be easily and reliably increased as compared with the conventional case.

  Further, according to the differential device 1 of the present embodiment, the side gear oil guide passage 33 formed in the spline hole 31 is inserted into the axle without impairing the coupling strength between the differential side gear 5 and the wheel drive shaft S by the spline. Since a larger amount of lubricating oil can be led from the hole 13 toward the pinion shaft 3 than in the prior art, and the flow passage area can be increased easily and reliably, the inside of the spline hole 31 from the axle insertion hole 13 can be increased. It is possible to increase the supply amount of the lubricating oil supplied to the pinion shaft 3 after passing through.

  Further, according to the differential device 1 of the present embodiment, the gear oil sump 23 formed at the position of the inner end surface of the opposed portion of the pinion shaft 3 and the differential pinion 4 increases the strength of the pinion shaft 3 and the differential pinion 4. The capacity of the lubricating oil to be captured and stored can be increased as compared with the conventional one without lowering, and the stored lubricating oil can be supplied from the entire circumference of the pinion shaft 3 to the pinion shaft 3 and the differential pinion 4 when the differential case 2 rotates. Therefore, the lubricating oil can be supplied easily and reliably to the sliding portion.

  Therefore, according to the differential device 1 of the present embodiment, the oil introduction flow path 12 is provided at the respective front end surfaces of the pair of boss portions 11, and the side gear oil is provided in the spline holes 31 of the pair of differential side gears 5. A sliding portion between the pinion shaft 3 and the differential pinion 4 is provided with a simple structure in which the guide channel 33 is provided and the gear oil sump 23 is provided at the position of the inner end surface of the opposing portion of the pinion shaft 3 and the differential pinion 4. The amount of lubricating oil supplied to the shaft can be increased easily and reliably compared to the prior art, and the lubricating oil can be efficiently and reliably supplied to the sliding portion between the pinion shaft 3 and the differential pinion 4. A good lubricating state of the sliding portion between the shaft 3 and the differential pinion 4 can be reliably maintained.

  Further, according to the differential device 1 of the present embodiment, the plurality of oil introduction grooves 12 a can easily form the oil introduction flow path 12, and the missing teeth easily form the side gear oil guide flow path 33. And the side gear oil guiding channel 33 can be easily increased, and the oil retaining annular groove 21 and the annular enlarged diameter portion 22 facilitate the gear oil reservoir 23. And the capacity of the lubricating oil retained in the gear oil sump 23 can be easily increased. Therefore, the amount of lubricating oil supplied to the sliding portion between the pinion shaft 3 and the differential pinion 4 can be easily increased, so that the good lubricating state of the sliding portion between the pinion shaft 3 and the differential pinion 4 can be more reliably maintained. be able to.

  Furthermore, according to the differential device 1 of the present embodiment, when the number of teeth of the spline teeth 31a is 27, the number of teeth to be missing is 5, so the differential side gear 5 and the wheel drive shaft S by the spline. The supply amount of the lubricating oil passing through the side gear oil guide passage 33 that guides the lubricating oil from the axle insertion hole 13 toward the pinion shaft 3 is held in the gear oil reservoir 23 without impairing the coupling strength with the gear shaft. It is possible to reliably prevent the lubricating oil from being consumed. As a result, a good lubrication state of the sliding portion between the pinion shaft 3 and the differential pinion 4 can be more reliably maintained.

  Furthermore, according to the differential device 1 of the present embodiment, the lubricating oil supplied to the axle insertion hole 13 via the oil introduction passage 12 is supplied to each of the pair of axle insertion holes 13 as the differential case 2 rotates. In this case, a case oil guide passage 14 for guiding the inside of the differential case 2 is formed, and one end of the case oil guide passage 14 is connected to the oil introduction passage 12. The lubricating oil supplied to the axle insertion hole 13 via the path 12 can be easily and reliably flowed toward the inside of the differential case 2 as the differential case 2 rotates.

  In addition, according to the differential device 1 of the present embodiment, the case oil groove 14a formed in a spiral shape toward the inside of the differential case 2 can easily form the case oil guide channel 14. As the differential case 2 rotates, the lubricating oil can flow easily and reliably toward the inside of the differential case 2.

  Furthermore, according to the differential device 1 of the present embodiment, the oil introduction groove 12a as the oil introduction flow path 12 formed on the tip surface of the boss portion 11 is directed toward the inner diameter side where the radially outer side is higher than the radially inner side. A bottom surface 12aa formed so as to be inclined, and a side surface composed of an inclined surface 12ab in which the outer peripheral edge of the boss portion 11 is arranged on the leading side in the rotation direction of the differential case 2 with respect to the inner peripheral edge of the boss portion 11. In addition, since it is configured to have an introduction oil sump 12ac that is recessed at a position adjacent to the inclined surface 12ab on the inner peripheral side of the bottom surface 12aa, the lubricating oil is formed in a flow path shape as compared with the conventional one. The shape is easy to flow in. Thereby, for example, even if the supply amount of the lubricating oil supplied to the differential device 1 is as low as about 150 cc / min, the supply amount of the lubricating oil to the sliding portion between the pinion shaft 3 and the differential pinion 4 is conventionally reduced. Therefore, it is possible to more reliably maintain a satisfactory lubrication state of the sliding portion, that is, a sufficient supply amount of lubricating oil in which the sliding portion is not seized.

  Furthermore, according to the differential device 1 of the present embodiment, the annular enlarged diameter portion 22 constituting a part of the gear oil sump 23 is formed by providing a chamfer having an inclined surface having an angle of about 10 °. From the rotation of the lubricating oil supplied to the outer peripheral surface of the pinion shaft 3 around the differential axis C1 of the pinion shaft 3 as the differential case 2 rotates, and the centrifugal force when the differential pinion rotates about the shaft axis C2 Scattering to the outer periphery can be prevented easily and reliably.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.

DESCRIPTION OF SYMBOLS 1 Differential apparatus 2 Differential case 3 Pinion shaft 4 Differential pinion 5 Differential side gear 11 Boss part 12 Oil introduction flow path 12a Oil introduction groove 12aa Bottom surface 12ab Inclined surface 12ac Oil reservoir for introduction 13 Axle insertion hole 14 Oil guide flow path 14a Case oil Groove 15 Bearing mounting portion 21 Oil retaining annular groove 22 Annular diameter enlarged portion 23 Gear oil sump 31 Spline hole 31a Spline teeth 33 Side gear oil guide passage C1 Differential axis (rotational axis of differential case)
C2 shaft axis (pinion shaft axis)
S Wheel drive shaft

Claims (4)

A pair of cylindrical bosses that are rotationally driven and have axle insertion holes that communicate with the inner and outer sides of which the inner peripheral surface rotatably supports one end of the left and right wheel drive shafts at both ends along the rotation axis. A differential case formed with,
A pinion shaft mounted in the differential case and rotating integrally with the differential case, the pinion shaft being arranged in a direction orthogonal to the rotational axis of the differential case;
A pair of differential pinions that are rotatably supported at both ends of the pinion shaft, are capable of revolving around the rotational axis of the differential case, and are capable of rotating about the axis of the pinion shaft;
A plurality of shafts that are coaxially arranged with the rotational axis of the differential case and are opposed to each other in a state of being engaged with the pair of differential pinions inside the differential case, and for spline-connecting one end of each of the left and right wheel drive shafts A pair of differential side gears in which a spline hole having a plurality of spline teeth is formed along the rotational axis;
A differential device comprising:
An oil introduction flow path for introducing lubricating oil supplied from the outside into the inside of the axle insertion hole along the radial direction is formed on the front end surface of each of the pair of boss portions. Each spline hole of the pair of differential side gears is formed with a side gear oil guide channel for guiding lubricating oil from the axle insertion hole toward the pinion shaft, and between the pinion shaft and the pair of differential pinions A differential device, characterized in that a gear oil sump capable of capturing and storing lubricating oil is formed at the position of the inner end surface of the facing portion. The oil introduction channel is formed by a plurality of oil introduction grooves that communicate the inside and outside of the tip surface of the boss part,
The side gear oil guide passage is formed by notching a part of a plurality of spline teeth formed in each spline hole of the pair of differential side gears,
The gear oil sump includes an oil retaining annular groove formed at an inner end surface position of an opposing portion of the outer peripheral surface of the pinion shaft facing each of the pair of differential pinions, and the pair of differential pinions. The differential device according to claim 1, wherein the differential device is formed by an annular diameter-enlarged portion formed at an inner end portion of each inner hole and expanding toward the outside in the axial direction.   3. The differential device according to claim 1, wherein when the number of spline teeth is 27, the number of teeth to be missing is 5 teeth. 4.   In each of the pair of axle insertion holes, case oil that guides the lubricating oil supplied to the axle insertion hole through the oil introduction passage toward the inside of the differential case as the differential case rotates. The induction channel is formed, and one end of the oil guide channel for the case is connected to the oil introduction channel. 4. Differential device.

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