JP2010203557A - Differential gear device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential gear device for a vehicle capable of enhancing the lubricity of sliding surface of a pinion shaft and a differential pinion gear even in lubricating oil of which viscosity is made low. <P>SOLUTION: The differential pinion gear device includes a plurality of infinitesimal holes 42a wherein the closer they approach a differential pinion gear 20, the more they decline to a pinion shaft 18. The device is also configured so that oil supply is continued as much as possible even in the lubricating oil of which viscosity is made low to enhance the lubricity because the oil supply is maintained until the lubricating oil stored in the infinitesimal holes 42a is run out even if an amount of oil supply in a differential case 14 becomes shortage by providing the axis C1 side of the differential gear 20 with a circular annulus porous member 38 which introduces the lubricating oil stored in the infinitesimal holes 42a along the infinitesimal holes 42a by a centrifugal force and supplies it to the sliding surface. In addition, the lubricity is further enhanced effectively for efficient supply to the sliding surface because the lubricating oil stored in the infinitesimal holes 42a is introduced along the infinitesimal holes 42a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a differential gear device for a vehicle, and more particularly to a technique for improving the lubricity of a portion of a pinion shaft that supports a differential pinion gear.

  A differential case in which a ring gear is fixed to the outer peripheral portion and supported at both ends so as to be rotatable around a single axis, a pair of side gears housed in the differential case and opposed to each other on the single axis, and the differential case A plurality of differential pinion gears that are accommodated between the pair of side gears in mesh with the pair of side gears and that are rotatably supported by a pinion shaft fixed to the differential case so as to be orthogonal to the one axis. A vehicle differential gear device is known. For example, the differential gear device for vehicles described in patent document 1 is it. The vehicle differential gear device described in Patent Document 1 includes a short cylindrical member provided between a plurality of differential pinion gears so as to be concentric with the uniaxial center and penetrated through a pinion shaft. In this differential gear device for a vehicle, the lubricating oil supplied between the plurality of differential pinion gears from the oil sump provided at both ends of the differential case through the lubricating oil passage formed on the inner peripheral surface of the end is By collecting the differential pinion gear to the part supported by the pinion shaft by being collected by the inner peripheral surface of the cylindrical member, the lubricity of the supporting part is enhanced.

JP-A-11-351360

  By the way, in the conventional differential gear device for a vehicle, the lubricating oil is supplied to the inside of the differential case from the inner and outer communication holes formed in the differential case by the lubricating oil stored in the housing supporting the differential case and scraped up by the ring gear. By being introduced into the differential case or, as described above, by being introduced into the differential case from the oil reservoirs provided at the end surfaces of both ends of the differential case through the lubricating oil passages formed on the inner peripheral surfaces of the both ends. It has come to be done. The lubricating oil supplied to the inside of the differential case lubricates the meshing portions of the side gear and the differential pinion gear and the sliding portions of the differential gear and the pinion shaft.

  However, in recent years, there has been a tendency for the lubricating oil to have a low viscosity, which reduces the oil retaining property of the lubricating oil supplied to the inside of the differential case, and the differential portion, that is, the sliding surface between the differential pinion gear and the pinion shaft. There was a problem that the lubricity decreased.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a vehicle capable of improving the lubricity between the differential pinion gear and the pinion shaft even when the lubricating oil has a reduced viscosity. It is to provide a differential gear device for use.

  In order to achieve this object, the gist of the invention according to claim 1 is that: (1) a differential gear case in which a ring gear is fixed to an outer peripheral portion and both end portions are supported rotatably around a single axis; A pair of side gears housed in the differential case and opposed to each other on the one axial center, and housed in a state in which the pair of side gears are engaged with each other between the pair of side gears in the differential case, and orthogonal to the one axial center in the differential case A differential gear device for a vehicle having a plurality of differential pinion gears rotatably supported by a pinion shaft fixed so as to perform, (2) adjacent to the one axial center side of the differential pinion gear A plurality of fibers or minute fibers that are fitted to the pinion shaft and are inclined toward the pinion shaft toward the differential pinion gear. A plurality of fibers or micropores, and lubricating oil retained in the micropores is guided along the plurality of fibers or micropores by centrifugal force generated with rotation about the uniaxial center, and the differential pinion gear An annular porous member is provided between the pinion shaft and the pinion shaft.

  According to the differential gear device for a vehicle of the first aspect of the invention, the differential pinion gear is fitted to the pinion shaft adjacent to the uniaxial center side of the differential pinion gear, and toward the differential pinion gear toward the pinion shaft. A plurality of slanted fibers or micropores, and lubricating oil retained in the plurality of fibers or micropores is formed in the plurality of fibers or micropores by centrifugal force generated with rotation around the uniaxial center. Since the annular porous member is guided along the differential pinion gear and supplied between the differential pinion gear and the pinion shaft, a part of the lubricating oil supplied to the inside of the differential case is retained in the porous member. Supply of lubricating oil between the differential pinion gear and the pinion shaft until there is no lubricating oil retained in the porous member even if the amount of oil supplied to the Since is maintained, even at low viscosity lubricating oil continuously as possible can be supplied to the lubricating oil between the differential pinion gears and the pinion shaft, it is possible to improve the lubricity. Further, since the lubricating oil retained in the porous member is guided along the plurality of fibers or micropores and efficiently supplied between the differential pinion gear and the pinion shaft, the lubricity is more effectively improved. Be improved. Further, since the lubricating oil is filtered when passing through the porous member, it is possible to prevent foreign matter from entering the sliding surface between the differential pinion gear and the pinion shaft.

  Here, preferably, the porous member is bundled in an annular shape by being bonded with, for example, resin or synthetic rubber in a state in which a plurality of fiber materials or tubular members made of natural or synthetic resin are radially arranged. Alternatively, it is manufactured by forming a minute hole communicating in the radial direction with, for example, a resin or synthetic rubber formed in an annular shape.

  Preferably, the porous member has a pinion shaft such that the micropores are directed to the differential pinion gear from alternating layers of an open-cell porous layer and a dense synthetic resin layer formed of, for example, foamed resin or polyurethane foam. Configured to head towards.

  Preferably, the porous member is provided with a reverse tapered surface (reverse conical surface) inclined toward the pinion shaft toward the differential pinion gear on the uniaxial center side. In this way, the lubricating oil that scatters from the uniaxial center side due to the centrifugal force is accumulated on the inner peripheral side of the reverse tapered surface of the porous member and guided between the differential pinion gear and the pinion shaft. It becomes easier to collect and lubricity is further improved.

  Preferably, the outer peripheral surface of the pinion shaft has a bottom surface that is parallel to the axial direction and faces the inner peripheral surface of the porous member and the sliding surface (inner peripheral surface) of the differential pinion gear. A plurality of lubricating oil circulation grooves are formed. In this way, the lubricating oil that oozes out from the porous member can be easily supplied to the sliding surface between the differential pinion gear and the pinion shaft through the plurality of lubricating oil flow grooves, so that the difference between the differential pinion gear and the pinion shaft The lubricity during the operation is further improved.

1 is a longitudinal sectional view showing a vehicle differential gear device to which the present invention is applied. It is a perspective view of the porous member shown in FIG. FIG. 3 is a cross-sectional view showing a cross section taken along the line III in FIG. 2.

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

  FIG. 1 is a longitudinal sectional view showing a vehicle differential gear device (hereinafter referred to as a differential gear device) 10 to which the present invention is applied. In FIG. 1, a differential gear device 10 is disposed in a common housing (not shown) (transaxle case or differential carrier) together with, for example, a transmission and a final reduction gear, and a lubricating oil stored in a predetermined amount in the housing. So as to be lubricated together with the transmission and the final reduction gear.

  The differential gear device 10 includes a differential gear 14 having a ring gear (final driven gear) 12 fixed to the outer peripheral portion thereof and supported by the housing so as to be rotatable about an axis (single axis) C1, and accommodated in the differential case 14. The pair of side gears 16 opposed to each other on the shaft center C1 and the pair of side gears 16 are accommodated in the differential case 14 so as to be engaged with the pair of side gears 16 so that the differential case 14 is orthogonal to the shaft center C1. And a pair of differential pinion gears 20 that are rotatably supported by a fixed pinion shaft 18. The differential gear device 10 is rotationally driven in accordance with the torque input from the transmission or the final reduction gear via the ring gear 12, and detects a rotational difference between a pair of left and right drive shafts and drive wheels (not shown) connected to the subsequent stage. The pair of drive shafts and drive wheels are rotationally driven while allowing.

  The differential case 14 has a main body portion 14a that houses a pair of side gears 16 and a pair of differential pinion gears 20, and a cylindrical shape that protrudes in the axial center C1 direction from the opening edges that the main body portion 14a has on both sides in the axial center C1 direction. And a pair of end portions 14b. Both end portions 14b are supported by the housing so as to be rotatable around the axis C1 through a pair of bearings. A pair of oil grooves 22 are formed in the inner peripheral surface 21 of both end portions 14b. The pair of oil grooves 22 are formed in a spiral shape from the end surfaces of both end portions 14b toward the inside of the main body portion 14a. These pair of oil grooves 22 are respectively inserted into the both end portions 14b and connected to the pair of side gears 16 so as to be able to transmit power to the pair of drive shafts. The lubricating oil passage for guiding the lubricating oil to the inside of the main body portion 14a of the differential case is formed.

  The differential case 14 includes a cylindrical outer peripheral surface 22 concentric with the axial center C1 formed in the main body portion 14a, and a flange portion 24 that protrudes from one end of the cylindrical outer peripheral surface 22 in the axial center C1 direction toward the outer peripheral side. I have. The ring gear 12 is fixed to the cylindrical outer peripheral surface 22 by, for example, press fitting or the like, and is fastened to the flange portion 24 by, for example, a plurality of bolts 26. The ring gear 12 is provided concentrically with the axial center C1 of the differential case 14.

  The pinion shaft 18 is a shaft-like member having both ends fitted into a pair of through holes 30 formed through the body portion 14a of the differential case 14 in the direction of the axis C2 perpendicular to the axis C1. Concentric through holes 32 and 34 that are orthogonal to the axis C2 are respectively formed at one end of the pinion shaft 18 and the main body 14a. The pinion shaft 18 is press-fitted into both the through holes 32 and 34, for example. It is prevented from coming off from the main body portion 14a by a pin 36 fitted by, for example. The pinion shaft 18 rotates about the axis C1 together with the differential case 14 when the differential case 14 is rotated about the axis C1.

  The pair of differential pinion gears 20 are a pair of bevel gears that are housed in a state of being inserted through the pinion shaft 18 in the main body portion 14a and are opposed to each other on the axis C2. The pair of differential pinion gears 20 are supported by the pinion shaft 18 so as to be relatively rotatable about the axis C2, and the differential case 14 and the pinion shaft 18 are rotated about the axis C1 by rotating the differential case 14 and the pinion shaft 18 around the axis C1. It is supposed to be.

  The pair of side gears 16 includes a pair of bevel gear portions 16a facing each other on the shaft center C1, and a pair of shaft portions 16b projecting outward from the back side of the bevel gear portions 16a in the direction of the shaft center C1. And is accommodated in a state of meshing with the pair of differential pinion gears 20 in the main body portion 14a. The shaft portion 16b is supported by the main body portion 14a so as to be rotatable around the axis C1. The pair of side gears 16 rotate around the axis C1 when the differential case 14, the pinion shaft 18, and the pair of differential pinion gears 20 are rotated around the axis C1. Here, at the time of the rotation, the pair of side gears 16 rotate at the same rotational speed around the axis C1 when the pair of differential pinion gears 20 does not rotate relative to the pinion shaft 18, respectively. When the differential pinion gear 20 rotates relative to the pinion shaft 18, the differential pinion gear 20 rotates around the axis C <b> 1 with a difference in rotational speed.

  In the differential gear device 10 configured as described above, the differential case 14 and the pinion shaft 18 are rotationally driven around the axis C1 in accordance with the torque input from the transmission or the final reduction gear via the ring gear 12, and a pair of side gears are driven. The pair of left and right drive shafts and drive wheels connected to the subsequent stage via a pair of differential pinion gears 20 and a pair of side gears 16 are respectively rotated while allowing a difference in rotational speed of 16.

  Here, the differential gear device 10 of the present embodiment is provided adjacent to each other on the axis C1 side of the pair of differential pinion gears 20, and is paired with a pair of annular porous members 38 respectively fitted to the pinion shaft 18. It has. Hereinafter, the porous member 38 will be described in detail.

  2 is a perspective view of the porous member 38 shown in FIG. 1, and FIG. 3 is a cross-sectional view showing a section taken along the line III in FIG. 1 to 3, the porous member 38 is an annular member that is provided adjacent to the end surface of the differential pinion gear 20 on the side of the axis C <b> 1 and is fitted to the pinion shaft 18. Further, the porous member 38 includes a reverse tapered surface (reverse conical surface) 40 that is inclined toward the pinion shaft 18 toward the differential pinion gear 20 on the axis C1 side. The porous member 38 includes a plurality of natural or synthetic resin tubular members 42 that are inclined toward the pinion shaft 18 toward the differential pinion gear 20 on the entire circumference around the axis C2. The tubular member 42 has a minute hole 42 a that is inclined toward the pinion shaft 18 toward the differential pinion gear 20 on the inner peripheral side. The porous member 38 is manufactured by bonding a plurality of tubular members 42 made of natural or synthetic resin radially, for example, by a resin 43 and bundled in an annular shape. Note that the central portion in the longitudinal direction of the pinion shaft 18 to which the porous member 38 is fitted has a large diameter, and the porous member 38 is prevented from moving toward the rotation center. Further, the porous member 38 is stuck to the differential pinion gear 20 side by centrifugal force during traveling.

  On the outer peripheral surface of the pinion shaft 18, a plurality of lubricants having a bottom surface that is parallel to the direction of the axis C <b> 2 and faces the inner peripheral surface of the porous member 38 and the sliding surface (inner peripheral surface) of the differential pinion gear 20. An oil circulation groove 44 is formed.

  In the differential gear device 10 including the porous member 38 configured as described above, the supply of the lubricating oil to the inside of the main body portion 14a of the differential case 14 is stored in the housing that rotatably supports the differential case 14, and the ring gear. Lubricating oil scooped up by 12 is introduced into the main body portion 14a from an internal / external communication hole (not shown) formed in the differential case 14, or both ends thereof from oil reservoirs provided at the distal end surfaces of both end portions 14b of the differential case 14 This is done by being introduced into the body portion 14a through the oil groove 22 formed in the inner peripheral surface 21 of 14b. The lubricating oil supplied to the inside of the main body portion 14a lubricates the meshing portions between the side gear 16 and the differential pinion gear 20 and the sliding portions between them and the differential case 14 and the pinion shaft 18.

  Here, the porous member 38 retains a part of the lubricating oil supplied to the inside of the main body portion 14a inside, that is, in the plurality of micro holes 42a. In this embodiment, when the lubricating oil is applied to the porous member 38, the lubricating oil is absorbed into the plurality of minute holes 42a by capillary action. When the porous member 38 is rotated around the axis C1 together with the differential gear device 10, the lubricating oil retained in the micro holes 42a in the plurality of tubular members 42 is rotated around the axis C1. Along with the micro holes 42 a, the centrifugal force generated along with the micro holes 42 a guides it and supplies it between the differential pinion 20 and the pinion shaft 18. Further, the plurality of lubricating oil flow grooves 44 scatter from the axial center C1 side by the centrifugal force and ooze out from the lubricating oil and the porous member 38 accumulated on the inner peripheral side of the reverse tapered surface 40 of the porous member 38. The lubricating oil is guided between the differential pinion 20 and the pinion shaft 18.

  As described above, according to the differential gear device 10 of the present embodiment, the differential pinion gear 20 is fitted to the pinion shaft 18 adjacent to the axial center C1 side of the differential pinion gear 20, and toward the pinion shaft 18 toward the differential pinion gear 20. A plurality of inclined tubular members 42 and a plurality of minute holes 42a formed on the inner peripheral side thereof are provided, and the lubricating oil retained in the plurality of minute holes 42a is rotated with the rotation around the axis C1. Since the annular porous member 38 that is guided along the minute hole 42 a by the generated centrifugal force and is supplied between the differential pinion gear 20 and the pinion shaft 18 is provided, it is supplied into the main body portion 14 a of the differential case 14. A part of the lubricating oil is retained in the minute hole 42a, and even if the amount of oil supplied to the inside of the main body portion 14a is insufficient, the retained lubricating oil in the minute hole 42a is lost. Since the supply of the lubricating oil between the differential pinion gear 20 and the pinion shaft 18 is maintained during this period, even if the lubricating oil has been lowered in viscosity, the lubricating oil is continuously supplied to the differential pinion gear 20 as much as possible. It can be supplied between the pinion shaft 18 and the lubricity can be improved. Further, since the lubricating oil retained in the micro holes 42a of the porous member 38 is guided along the micro holes 42a, the lubricating oil is efficiently supplied between the differential pinion gear 20 and the pinion shaft 18, so that it is more effective. Therefore, lubricity is improved. Further, since the lubricating oil is filtered when passing through the porous member 38, it is possible to prevent foreign matter from entering the sliding surface between the differential pinion gear 20 and the pinion shaft 18.

  Further, according to the differential gear device 10 of the present embodiment, the porous member 38 has a reverse tapered surface (reverse conical surface) 40 that is inclined toward the pinion shaft 18 toward the differential pinion gear 20 toward the axis C1. It has. In this way, the lubricating oil scattered from the axial center C1 side due to the centrifugal force is accumulated on the inner peripheral side of the reverse tapered surface 40 and guided between the differential pinion gear 20 and the pinion shaft 18, so that the lubricating oil further increases. It becomes easy to collect and lubricity is further improved.

  Further, according to the differential gear device 10 of the present embodiment, the outer peripheral surface of the pinion shaft 18 is parallel to the axial center C2 direction, and the inner peripheral surface of the porous member 38 and the sliding surface of the differential pinion gear 20. A plurality of lubricating oil circulation grooves 44 having a bottom surface facing the (inner peripheral surface) are formed. In this way, the lubricating oil that oozes out from the porous member 38 is easily supplied to the sliding surface between the differential pinion gear and the pinion shaft through the plurality of lubricating oil flow grooves 44, so that the differential pinion gear 20 and the pinion shaft The lubricity between the two is further improved.

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

  For example, in the above-described embodiment, the porous member 38 includes the plurality of minute holes 42a that are inclined toward the pinion shaft 18 toward the differential pinion gear 20 on the entire circumference around the axis C2. 42a does not necessarily have to be provided on the entire circumference around the axis C2. Even if it is provided in a part, there is a temporary effect.

  In the above-described embodiment, since the porous member 38 has the micropores 42a, the porous member 38 is annularly bonded with, for example, the resin 43 in a state where the plurality of tubular members 42 made of natural or synthetic resin are radially arranged. However, the present invention is not limited to this. For example, the micro holes 42a communicating in the radial direction may be formed in, for example, a resin or synthetic rubber formed in an annular shape.

  In the above-described embodiment, the porous member 38 includes the plurality of minute holes 42a that incline toward the pinion shaft 18 toward the differential pinion gear 20. However, the porous member 38 is not limited to this. You may provide the some fiber which inclines toward the pinion shaft 18 so that it goes. In this case, the porous member 38 is manufactured by, for example, bonding a plurality of natural or synthetic resin fiber materials in a radially arranged state and bonding them with, for example, resin or synthetic rubber and bundling them in an annular shape. The In addition, the porous member 38 is directed to the pinion shaft as the micropores are directed to the differential pinion gear from alternate layers of an open-celled porous layer and a dense synthetic resin layer formed of, for example, foamed resin or polyurethane foam. It may be configured as follows.

  In the above-described embodiment, the porous member 38 includes the reverse tapered surface (reverse conical surface) 40 that is inclined toward the pinion shaft 18 toward the differential pinion gear 20 on the axis C1 side. The tapered surface 40 is not necessarily provided.

  In the above-described embodiment, the outer peripheral surface of the pinion shaft 18 has a plurality of bottom surfaces that are parallel to the direction of the axis C2 and face the inner peripheral surface of the porous member 38 and the sliding surface of the differential pinion gear 20. The lubricating oil circulation groove 44 is formed, but the lubricating oil circulation groove 44 is not necessarily provided.

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

10: differential gear device for vehicle 12: ring gear 14: differential case 16: side gear 18: pinion shaft 20: differential pinion gear 38: porous member 42a: minute hole C1: axis (one axis)

Claims (1)

A ring gear is fixed to the outer periphery, and both ends are supported so as to be rotatable around a single axis, a pair of side gears housed in the differential case and opposed to each other on the single axis, and the differential case A plurality of differential pinion gears housed in a state of meshing with the pair of side gears between the pair of side gears and rotatably supported by a pinion shaft fixed to the differential case so as to be orthogonal to the one axis. A differential gear device for a vehicle,
A plurality of fibers or fine holes that are fitted to the pinion shaft adjacent to the uniaxial center side of the differential pinion gear and are inclined toward the pinion shaft side toward the differential pinion gear, Alternatively, the lubricating oil retained in the microholes is guided along the plurality of fibers or microholes by the centrifugal force generated with the rotation around the uniaxial center and supplied between the differential pinion gear and the pinion shaft. A vehicle differential gear device comprising an annular porous member.

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