JP2020070839A - Lubrication structure of differential mechanism - Google Patents

Abstract

To provide a lubrication structure of a differential mechanism which can supply lubrication oil to the differential mechanism with a simple structure.SOLUTION: A lubrication structure of a differential mechanism 90 which transmits driving force to left and right wheels and absorbs a rotation speed difference includes: a crown gear 80 fixed to a differential case which houses the differential mechanism; a pinion gear 72 which has a rotation center axis intersecting with or located at a twisted position relative to a rotation center axis of the differential mechanism and engages with the crown gear; a lubrication oil guide part 83 which is provided at the inner diameter side of the crown gear and guides lubrication oil discharged from an engagement position between the crown gear and the pinion gear to the inner diameter side of the crown gear to an interior of the differential case of the differential mechanism; and an opening 91 which is formed at the differential case C and introduces the lubrication oil guided by the lubrication oil guide part to the differential mechanism. The lubrication oil guide part has a taper surface part which is formed on an inner peripheral surface of the crown gear and in which its diameter expands at the differential mechanism side relative to the teeth side when viewed in a rotation center axis direction of the crown gear.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a lubricating structure of a differential mechanism that transmits power while absorbing a difference in rotational speed between left and right wheels in a vehicle such as an automobile.

In vehicles such as automobiles, the rotational output of a driving power source such as an engine is decelerated or increased by a transmission and further decelerated by a final reduction gear, and then left and right via a differential mechanism (differential) or a drive shaft. Is transmitted to the wheels (driving wheels).
In the final reduction gear for the front wheels of the vehicle having a vertical transmission in which the rotary shaft is arranged along the vehicle front-rear direction, and in the final reduction gear for the rear wheels driven via the propeller shaft, as a gear mechanism for reduction, A hypoid gear, which is a staggered shaft bevel gear, may be used.

The hypoid gear is configured to have a pinion gear and a crown gear that are arranged at positions where the rotation center axes are twisted (positions where they do not intersect).
When the hypoid gear is used in the final reduction gear, a differential mechanism is usually attached to the inner diameter side of the crown gear.
The differential mechanism transmits the driving force to the left and right wheels and absorbs the rotation speed difference between the left and right wheels due to turning or the like.
The differential mechanism is provided, for example, between a pair of left and right side gears connected to the left and right wheels via a drive shaft and the like, and revolves together with the crown gear, and the rotational speed difference between the left and right wheels is When it occurs, it is configured to have a pinion gear that rotates to allow relative rotation of the left and right side gears.
Since the driving force is constantly applied to the differential mechanism when the vehicle is traveling, it is necessary to supply sufficient lubricating oil to maintain a good lubricating state in order to ensure reliability.

  As a conventional technique relating to lubrication of a differential mechanism of a vehicle, for example, in Patent Document 1, in order to effectively supply lubricating oil to the inside of a differential cage of a differential gear, in order to effectively supply the lubricating oil to the differential gear, the outer periphery of a drive shaft is surrounded by the differential gear and By covering the rear surface of the ring gear, the rear surface of the ring gear has a cover defining a space communicating with the periphery of the side gear, and the cover has an opening through which lubricating oil can flow from the outside. It is described that it is formed.

Japanese Patent Laid-Open No. 2016-196951

In recent years, there has been a demand for reduction in size and weight of a power transmission device for a vehicle, and improvement in efficiency, and it has been required to make peripheral components such as a final reduction gear and a differential mechanism compact and simple.
On the other hand, in the case of the technology that supplies the lubricating oil by using the additional new parts such as the cover part as in the above-mentioned conventional technology, a space for housing these parts is required, and the number of parts also increases. Resulting in.
In view of the problems described above, an object of the present invention is to provide a lubricating structure for a differential mechanism that can supply lubricating oil to the differential mechanism with a simple configuration.

The present invention solves the above-mentioned problems by the following solving means.
The invention according to claim 1 is a lubrication structure of a differential mechanism that transmits a driving force to a left wheel and a right wheel, and absorbs a rotational speed difference between the left wheel and the right wheel. A crown gear that is concentric with the rotation center axis of the differential gear and is fixed to a differential case that accommodates the differential mechanism, and a rotation center axis that intersects or twists with respect to the rotation center axis of the differential mechanism. Lubricating a pinion gear that meshes with a crown gear and a lubricating oil that is provided on the inner diameter side of the crown gear and is discharged from the meshing point of the crown gear and the pinion gear to the inner diameter side of the crown gear to the differential mechanism side. An oil guide portion and an opening formed in the differential case for introducing the lubricating oil guided by the lubricating oil guide portion into the differential mechanism are provided, and the lubricating oil guide portion includes the crown. Is formed on the inner peripheral surface of Ya, a lubrication structure of a differential mechanism which is characterized by having a tapered surface portion of the differential mechanism side is enlarged than the face side of the rotational center axis of the crown gear.

According to a second aspect of the present invention, the lubricating oil guide portion is formed on an inner peripheral surface of the crown gear, and has a spiral groove or a spiral groove that conveys the lubricating oil to the differential mechanism side in accordance with rotation of the crown gear. The lubrication structure for a differential mechanism according to claim 1, wherein the lubrication structure has a ridge.
The invention according to claim 3 is a lubrication structure of a differential mechanism that transmits a driving force to a left wheel and a right wheel, and absorbs a rotational speed difference between the left wheel and the right wheel. A crown gear that is concentric with the rotation center axis of the differential gear and is fixed to a differential case that accommodates the differential mechanism, and a rotation center axis that intersects or twists with respect to the rotation center axis of the differential mechanism. Lubricating a pinion gear that meshes with a crown gear and a lubricating oil that is provided on the inner diameter side of the crown gear and is discharged from the meshing point of the crown gear and the pinion gear to the inner diameter side of the crown gear to the differential mechanism side. An oil guide portion and an opening formed in the differential case for introducing the lubricating oil guided by the lubricating oil guide portion into the differential mechanism are provided, and the lubricating oil guide portion includes the crown. A lubrication structure for a differential mechanism, which has a spiral groove or a protrusion formed on an inner peripheral surface of the yarn carrier and conveys lubricating oil to the differential mechanism side in accordance with rotation of the crown gear. .
According to each of these aspects, when the tooth of the crown gear and the tooth of the pinion gear are meshed with each other, the lubricating oil discharged toward the inner diameter side of the crown gear or the lower portion of the crown gear rotating and passing through the lubricating oil sump The lubricating oil that adheres to the inner diameter side of the crown gear is guided to the differential mechanism side by the lubricating oil guide section that is provided on the inner diameter side of the crown gear, so that a simple and compact structure is achieved inside the crown gear. Lubricating oil can be supplied to the dynamic mechanism to prevent problems such as seizure and improve reliability.
Further, the other opening (window portion) provided for lubrication in the differential case accommodating the differential mechanism can be simplified or eliminated, and the strength of the differential case can be easily secured, so that the size and weight of the differential case can be reduced. be able to.

  As described above, according to the present invention, it is possible to provide a lubrication structure for a differential mechanism that can supply lubricating oil to the differential mechanism with a simple configuration.

1 is a schematic cross-sectional view of a transmission having a differential mechanism lubrication structure according to a first embodiment of the present invention. FIG. 3 is a perspective view around a hypoid gear in the transmission of the first embodiment. It is a schematic cross-sectional view of the crown gear in the lubrication structure of the differential mechanism of the first embodiment. FIG. 6 is a schematic cross-sectional view of a crown gear in a lubrication structure of a differential mechanism of a comparative example of the present invention. FIG. 6 is a schematic cross-sectional view of a crown gear in a second embodiment of a lubrication structure for a differential mechanism to which the present invention is applied. It is a typical sectional view of a crown gear in a lubrication structure of a differential mechanism to which the present invention is applied in a third embodiment.

<First Embodiment>
Hereinafter, a first embodiment of a lubrication structure for a differential mechanism to which the present invention is applied will be described.
The lubrication structure of the differential mechanism according to the first embodiment is provided in, for example, a transmission that is mounted on an automobile such as a passenger car and that shifts a rotational output of an engine that is a power source for driving the vehicle.
In the first embodiment, the transmission is, for example, a chain type continuously variable transmission (CVT).

FIG. 1 is a schematic cross-sectional view of the transmission according to the first embodiment, showing a state as viewed from the side of the vehicle.
FIG. 2 is a perspective view around the hypoid gear in the transmission of the first embodiment.
In the first embodiment, the engine has a so-called vertical layout in which the crankshaft is mounted along the vehicle front-rear direction.

The transmission 1 includes, for example, a torque converter 20, a forward / reverse switching mechanism 30, a primary pulley 40, a secondary pulley 50, and a chain 60 inside a transmission case 10 formed by subjecting a cast product of an aluminum alloy to predetermined machining. , Pinion shaft 70, crown gear 80, front differential 90, transfer clutch 100, control valve 110 and the like.
At the front of the transmission case 10, there is formed a differential housing 11 that accommodates a final reduction gear including a pinion gear 72, a crown gear 80, a front differential 90, and the like.
Lubricating oil is stored in the lower portion of the differential housing 11 to a predetermined oil level.
The oil level of the lubricating oil is set so that the lower part of the crown gear 80 is immersed.

The torque converter 20 is a fluid coupling to which an output shaft of an engine (not shown) is connected, and functions as a starting device that allows the vehicle to start from a zero vehicle speed state.
The torque converter 20 has a stator connected to the input shaft, a turbine connected to the output shaft, and a stator provided between them and fixed to the transmission case 10, and the like.
The torque converter 20 includes a lockup clutch that restrains relative rotation between the impeller and the turbine when in a predetermined operating state.
The engagement force of the lockup clutch is controlled by a transmission control unit (not shown).
The output shaft 21 of the torque converter 20 is connected to the forward / reverse switching mechanism 30.

The forward / reverse switching mechanism 30 reverses the output rotation of the torque converter 20 to allow the vehicle to reverse.
The forward / reverse switching mechanism 30 directly connects the output shaft 21 of the torque converter 20 and the input shaft of the primary pulley 40 during forward movement, and transmits the rotation of the output shaft 21 to the primary pulley 40 as it is.
Further, when the vehicle is moving backward, the forward-reverse switching mechanism 30 reverses the rotational direction of the output shaft 21 and transmits it to the primary pulley 40 to reverse the rotational direction after the primary pulley 40 and switch the vehicle between forward and backward. ..
The forward / reverse switching mechanism 30 includes a planetary gear mechanism in which a plurality of planetary gears supported by a planetary carrier are incorporated between a sun gear and an internal gear that are concentrically arranged.
The sun gear and the internal gear are connected to the input shaft and the output shaft of the forward / reverse switching mechanism 30, respectively.
In the forward / reverse switching mechanism 30, rotation of the planetary gears is restricted during forward movement, and the sun gear and the internal gear rotate in the same direction at the same angular velocity.
At this time, the planetary gear also revolves at the same rotation speed as the sun gear and the like.
When the vehicle is moving backward, the planetary gear rotates on its own axis, so that the sun gear and the internal gear rotate in opposite directions.

The primary pulley 40, the secondary pulley 50, and the chain 60 cooperate with each other to configure a transmission mechanism section (variator) of the transmission 1.
The primary pulley 40 and the secondary pulley 50 are each rotatable around a rotation center axis arranged in parallel.
The primary pulley 40 and the secondary pulley 50 each have a fixed sheave and a movable sheave that sandwich the chain 60.

The chain 60 is wound around the primary pulley 40 and the secondary pulley 50, and transmits power between them.
The chain 60 is configured by connecting a plurality of rocker pins held between sheaves with a link plate.
The primary pulley 40 and the secondary pulley 50 are capable of steplessly changing the distance between the fixed sheave and the movable sheave under the control of a transmission control unit (not shown), whereby the chain 60 is wound. Gear shifting can be performed by changing the effective diameter.

The rotation center axis of the primary pulley 40 is arranged coaxially with the rotation center axis of the engine crankshaft, the torque converter 20, and the sun gear of the forward / reverse switching mechanism 30.
The rotation center axis of the primary pulley 40 is arranged along the front-rear direction of the vehicle.
The rotation center axis of the secondary pulley 50 is arranged below the rotation center axis of the primary pulley 40.

The output shaft 51 of the secondary pulley 50 is provided with a reduction drive gear 52 that drives the pinion shaft 70.
The pinion shaft 70 is a rotation shaft arranged in parallel with the rotation center axis of the secondary pulley 50.
The pinion shaft 70 is provided with a reduction driven gear 71, a pinion gear 72, and a transfer drive gear 73.

The reduction driven gear 71 meshes with the reduction drive gear 52 of the secondary pulley 50, and transmits power from the secondary pulley 50 while decelerating the rotation speed.
The reduction driven gear 71 is provided at an intermediate portion of the pinion shaft 70.
The pinion gear 72 meshes with and drives the crown gear 80.
The pinion gear 72 is provided at the front end portion (end portion on the engine side) of the pinion shaft 70.
The transfer drive gear 73 meshes with a transfer driven gear 92 provided on the input shaft 101 of the transfer clutch 100 to transmit power to the transfer clutch 100.
The transfer drive gear 73 is provided at the rear end of the pinion shaft 70.

The crown gear 80 is an annular gear that is arranged with its rotation center axis along the vehicle width direction.
On one surface portion of the crown gear 80 in the axial direction, teeth that mesh with the teeth of the pinion gear 72 are arranged in the circumferential direction.
The side on which the teeth are formed in the axial direction of the crown gear 80 will be described below as a tooth side portion 81.

The crown gear 80 is driven by the pinion gear 72 of the pinion shaft 70.
The center axis of rotation of the crown gear 80 is orthogonal to the center axis of rotation of the pinion shaft 70 when viewed from above, and is located at a position lower than the center axis of rotation of the pinion shaft 70 when viewed from the vehicle width direction, a so-called twisted position. Have a relationship.
The crown gear 80 and the pinion gear 72 form a hypoid gear (a staggered shaft gear) that serves as a final reduction gear for the front wheels.

The crown gear 80 and the pinion gear 72 are spiral bevel gears having a predetermined helix angle.
In the first embodiment, for example, as shown in FIG. 2, the crown gear 80 is twisted to the right and the pinion gear 72 is twisted to the left.
A front differential 90 is attached to the side of the crown gear 80 opposite to the tooth side portion 81 side.
A shaft portion (not shown) for transmitting power from the front differential 90 to the right front wheel is inserted through the opening 82 at the center of the crown gear 80, and a flow for introducing lubricating oil from the tooth side portion 81 side to the front differential 90 side is provided. It also functions as a road.

The front differential 90 is a differential mechanism that transmits the power input from the crown gear 80 to the left and right front wheels and allows a difference in rotational speed between the left and right front wheels during turning or the like.
The front differential 90 has, for example, a pair of left and right side gears to which left and right drive shafts are connected, a rotation shaft fixed to the crown gear 80, and pinion gears that mesh with the left and right side gears, respectively. To be done.
For example, when there is no rotation speed difference between the left and right front wheels, such as when the vehicle goes straight ahead, the pinion gear does not rotate, and the left and right side gears rotate integrally with the crown gear 80 without relative rotation.
On the other hand, when there is a rotation speed difference between the left and right front wheels, such as when turning, the pinion gear rotates to cause a rotation speed difference between the left and right side gears, allowing the rotation speed difference between the left and right front wheels to be allowed. There is.

  An opening 91 that allows lubricating oil to be introduced from the inside of the opening 82 to the inside of the differential case C is formed in a portion of the front differential 90 that is exposed in the opening 82 of the crown gear 80 in the differential case C.

The transfer clutch 100 transmits the driving force transmitted from the pinion shaft 70 to the rear wheel side and adjusts the torque transmitted to the rear wheel side.
The transfer clutch 100 includes, for example, a hydraulic wet multi-plate clutch, and its engagement force (transmission torque) is appropriately controlled by the transmission control unit according to the traveling state of the vehicle.
The transfer clutch 100 is arranged on the rear side of the primary pulley 40.
The input shaft 101 of the transfer clutch 100 projects to the front side of the transfer clutch 100, and a transfer driven gear 102 is provided.
The output shaft 103 of the transfer clutch 100 projects to the rear side of the transfer clutch 100, and its rear end is connected to the front end of the propeller shaft P.
The propeller shaft P is a rotary shaft that transmits a driving force to the rear wheels via a pinion gear, a crown gear, a rear differential, and a rear drive shaft, which are provided in the rear portion of the vehicle body, which are not shown.

The control valve 110 supplies oil (CVT fluid) pressurized and supplied by an oil pump (not shown) to each part in the transmission 1 in response to a command from a transmission control unit (not shown).
The control valve 110 is arranged in the transmission case 10 above the output shaft 21 of the torque converter 20.

The lubricating structure of the differential mechanism of the first embodiment has a function of supplying lubricating oil to the front differential 90 by the structure described below.
FIG. 3 is a schematic cross-sectional view of the crown gear in the lubrication structure of the differential mechanism of the first embodiment.
FIG. 3 shows a state in which the crown gear 80 is cut along a cross section including the rotation center axis. (Same for FIGS. 4 and 5 described later)
In the first embodiment, the inner peripheral surface 83 of the opening 82 of the crown gear 80 is formed in a tapered shape whose inner diameter continuously changes along the axial direction of the crown gear 80.
The inner peripheral surface 83 is formed so that the front differential 90 side has a larger diameter than the tooth side portion 81 in the axial direction of the crown gear 80.
The inner peripheral surface 83 is a lubricating oil guide portion that guides the lubricating oil from the tooth side portion 81 side to the front differential 90 side by utilizing the centrifugal force when the crown gear 80 rotates.

Hereinafter, the effect of the above-described first embodiment will be described in comparison with a comparative example of the present invention described below.
In the comparative example and the second embodiment described later, the same parts as those in the above-described first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Differences will be mainly described.
FIG. 4 is a schematic cross-sectional view of the crown gear in the lubricating structure of the differential mechanism of the comparative example of the present invention.
In the comparative example, the inner peripheral surface 83 of the opening 82 of the crown gear 80 is formed with a constant inner diameter over the entire length of the crown gear 80 in the rotation center axis direction.

When the pinion gear 72 and the crown gear 80 relatively rotate as the vehicle travels, the lubricating oil extruded from between the teeth of the pinion gear 72 and the teeth of the crown gear 80 at the meshing position is moved to the inner diameter side of the crown gear 80. be introduced.
When the lubricating oil flows into the opening 82 of the crown gear 80, a part of the lubricating oil adheres to the inner peripheral surface 83. Further, on the inner peripheral surface 83 of the crown gear 80, there is lubricating oil that is attached when passing through the lubricating oil sump below the differential housing 11 when the crown gear 80 rotates.
However, in the case of the comparative example, most of these lubricating oils stay inside the opening 82 and do not contribute to the lubrication of the front differential 90.

  On the other hand, in the first embodiment, when the lubricating oil adheres to the inner peripheral surface 83 of the crown gear 80, the inner peripheral surface 83 is formed in a tapered shape, so that the lubricating oil is centrifugally generated to cause the front differential 90 to move. After moving to the side and reaching the end of the crown gear 80 on the front differential 90 side, the crown gear 80 is supplied to the inside of the front differential 90 through the opening 91 and lubricates the side gear, the pinion gear, and the like.

According to the first embodiment described above, the lubricating oil discharged from the meshing portion of the hypoid gear to the inner diameter side of the crown gear 80 is tapered by utilizing the centrifugal force during rotation of the crown gear 80. By carrying the lubricant to the front differential 90 side, the lubricating oil can be supplied to the front differential 90 with a simple and compact structure.
As a result, the lubrication state of the front differential 90 can be improved, troubles such as seizure due to insufficient lubrication can be prevented, and the reliability of the differential mechanism can be improved.
Further, even if the opening for oil supply formed on the outer peripheral surface of the differential case C of the front differential 90 is reduced or eliminated, the lubricating performance can be ensured and the strength of the differential case C can be easily ensured. Therefore, the structure of the front differential 90 can be simplified and the size and weight of the front differential 90 can be reduced.
Further, by making the inner peripheral surface 83 of the crown gear 80 tapered, the weight of the crown gear 80 itself can be reduced.

<Second Embodiment>
Hereinafter, a second embodiment of the lubrication structure of the differential mechanism to which the present invention is applied will be described.
FIG. 5 is a schematic cross-sectional view of a crown gear in the lubrication structure of the differential mechanism of the second embodiment.

As shown in FIG. 5, in the crown gear 80 of the second embodiment, the inner peripheral surface 83 of the opening 82 is formed with a constant inner diameter, as in the comparative example described above.
In the second embodiment, a protrusion 84 is formed on the inner peripheral surface 83.
The protrusion 84 is formed in a rib shape protruding from the surface of the inner peripheral surface 83.
The longitudinal direction of the ridge 84 extends along the inner peripheral surface 83 in a spiral shape concentric with the rotation center axis of the crown gear 80.
The ridges 84 are discharged from the meshing points of the teeth of the crown gear 80 and the teeth of the pinion gear 72, and the lubricating oil introduced into the opening 82 and the crown gear 80 pass through the lubricating oil reservoir below the differential case 11. At this time, the lubricating oil guide portion has a function of transporting the lubricating oil attached to the inner peripheral surface 83 from the tooth side portion 81 to the front differential 90 side in accordance with the rotation of the crown gear 80 when the vehicle moves forward.

  According to the second embodiment described above, the lubricating oil discharged from the meshing portion of the hypoid gear to the inner diameter side of the crown gear 80 is forwarded by the spiral ridge 84 by utilizing the rotation of the crown gear 80 during forward movement. By transporting to the differential 90 side, the lubricating oil can be supplied to the front differential 90 with a simple and compact configuration.

<Third Embodiment>
Hereinafter, a third embodiment of a lubrication structure for a differential mechanism to which the present invention is applied will be described.
FIG. 6 is a schematic cross-sectional view of a crown gear in the lubrication structure for the differential mechanism of the third embodiment.
As shown in FIG. 6, in the crown gear 80 of the third embodiment, the inner peripheral surface 83 of the opening 82 is formed in a tapered shape as in the first embodiment.
Further, on the inner peripheral surface 83, a spiral protrusion 84 similar to that of the second embodiment is formed.
According to the third embodiment described above, the front differential 90 is obtained by the synergistic effect of the same taper shape of the inner peripheral surface 83 as that of the first embodiment and the same effect of the protrusion 84 as that of the second embodiment. The supply of lubricating oil to the can be promoted.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes can be made, which are also within the technical scope of the present invention.
(1) The shape, the structure, the material, the manufacturing method, the arrangement, the number, and the like of the transmission that includes the differential mechanism and the members that configure the lubrication structure of the differential mechanism are not limited to those in the above-described embodiments, and are appropriate. Can be changed.
(2) Each of the above-described embodiments is used, for example, in a front wheel differential mechanism of a vehicle having a vertical transmission, but the present invention is not limited to this, and is driven via, for example, a propeller shaft. It can also be used for lubrication of the differential mechanism provided in the final reduction gear for rear wheels.
(3) In each of the embodiments, the differential mechanism is composed of a side gear and a pinion gear as an example, but the present invention is a differential mechanism having a torque sensing type differential limiting function using, for example, a worm gear. It can also be applied to lubrication of other types of differential mechanisms.
(4) In the second embodiment, the spiral projection is provided on the inner peripheral surface of the crown gear, but a spiral groove may be formed instead of or together with the projection.
(5) Each of the embodiments relates to the hypoid gear in which the rotation center axis of the pinion gear and the rotation center axis of the crown gear are arranged in a twisted manner, but the present invention is not limited to this, and the rotation of the pinion gear is not limited to this. It can also be applied to a spiral bevel gear in which the central axis and the central axis of rotation of the crown gear intersect.

1 transmission 10 transmission case 11 differential housing 20 torque converter 21 output shaft 30 forward / reverse switching mechanism 40 primary pulley 50 secondary pulley 51 output shaft 52 reduction drive gear 60 chain 70 pinion shaft 71 reduction driven gear 72 pinion gear 73 transfer drive gear 80 crown gear 81 tooth side part 82 opening 83 inner peripheral surface 84 ridge
90 Front Differential C Differential Case 91 Opening 100 Transfer Clutch 101 Input Shaft 102 Transfer Driven Gear 103 Output Shaft 110 Control Valve P Propeller Shaft

Claims (3)

A lubricating structure of a differential mechanism that transmits a driving force to a left wheel and a right wheel, and absorbs a rotational speed difference between the left wheel and the right wheel,
A crown gear that is fixed to a differential case that is concentric with the rotation center axis of the differential mechanism and that houses the differential mechanism,
A pinion gear that has a rotation center axis that intersects or twists with respect to the rotation center axis of the differential mechanism and that meshes with the crown gear;
A lubricating oil guide portion which is provided on the inner diameter side of the crown gear and which guides the lubricating oil discharged to the inner diameter side of the crown gear from the meshing point of the crown gear and the pinion gear to the differential mechanism side,
An opening formed in the differential case for introducing lubricating oil guided by the lubricating oil guide portion into the differential mechanism,
The lubricating oil guide portion is formed on an inner peripheral surface of the crown gear, and has a tapered surface portion in which a diameter of the differential mechanism side is expanded from a tooth side in a rotation center axis direction of the crown gear. Lubrication structure of dynamic mechanism. The lubricating oil guide portion is formed on an inner peripheral surface of the crown gear, and has a spiral groove or a ridge that conveys lubricating oil to the differential mechanism side in accordance with rotation of the crown gear. The lubrication structure for the differential mechanism according to claim 1. A lubricating structure of a differential mechanism that transmits a driving force to a left wheel and a right wheel, and absorbs a rotational speed difference between the left wheel and the right wheel,
A crown gear that is fixed to a differential case that is concentric with the rotation center axis of the differential mechanism and that houses the differential mechanism,
A pinion gear that has a rotation center axis that intersects or twists with respect to the rotation center axis of the differential mechanism and that meshes with the crown gear;
A lubricating oil guide portion which is provided on the inner diameter side of the crown gear and which guides the lubricating oil discharged to the inner diameter side of the crown gear from the meshing point of the crown gear and the pinion gear to the differential mechanism side,
An opening formed in the differential case for introducing lubricating oil guided by the lubricating oil guide portion into the differential mechanism,
The lubricating oil guide portion is formed on an inner peripheral surface of the crown gear, and has a spiral groove or a ridge that conveys lubricating oil to the differential mechanism side in accordance with rotation of the crown gear. Differential mechanism lubrication structure.

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