JPH02286946A - Rotation difference sensitive differential limiter - Google Patents

Abstract

PURPOSE:To improve the lubricating performance of a cam face without increasing the number of parts by forming an operating oil sealing chamber with a notch face having an oil hole on the outer peripheral face of the cylinder of a cam housing member and the inner face of the cylinder of a differential case. CONSTITUTION:When relative rotation is generated between a case cover 20 and a rotor 30 in accordance with difference in rotating speed between right and left wheels, a driving piston 40 in peripheral contact with a cam 21 radially reciprocates and makes differential limitation to decrease the distribution of driving force at a high speed rotating side and increase it at a low speed rotat ing side. An operating oil sealing chamber 103 is formed. As a cam face lubricat ing structure 100, between the notch face 20b of the outer periphery of a cam housing (case cover) 20 and the inner peripheral face of a differential case 10. When relative rotation is generated, operating oil flows into the operating oil sealing chamber 103 from a first oil hole 101 to lubricate the cam face 21 through a second oil hole 102. Thus, the lubricating performance of the cam face cam be improved without increasing the number of parts.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a rotation difference sensitive system that limits the differential by converting fluid pressure generated according to the rotation difference between left and right wheels or front and rear wheels into a differential limiting torque. The present invention relates to a type differential limiting device.

(Prior Art) The present applicant has proposed a rotation difference sensitive type differential limiting device built into a differential device using a rotation difference sensitive coupling (abbreviation: orifice coupling) as a differential limiting means, in the application filed in 1983- 1844
We previously proposed the device described in the application documents of No. 85C (unpublished).

This prior art includes, as a first embodiment, a housing member integrally formed with a differential case and a rotor member integrally formed with one side gear. As a second embodiment, a device for restricting We have shown a device that uses rotation as is to limit differential movement.

That is, in the case of the device of the first embodiment, the difference between the average value of the rotational speeds of the left and right wheels and the rotational speed of one wheel becomes the relative rotational speed difference of the differential limiting means, whereas in the device of the second embodiment In this case, the rotational speed difference between the left and right wheels directly becomes the relative rotational speed difference of the differential limiting means.

Therefore, in the case of the second embodiment, the relative rotational speed difference of the differential limiting means is doubled compared to the first embodiment, and the responsiveness when relative rotation occurs and the good differential limiting torque characteristic part can be used. It is preferable.

(Problems to be Solved by the Invention) However, the device shown in the second embodiment has a structure including a housing member and a rotor member connected to each of the pair of side gears, and is different from the first embodiment. Unlike the case where the cam surface is formed inside the differential case, the cam surface is formed on the housing member placed inside the differential case, so a high relative rotational speed difference continues. If this occurs, the supply of hydraulic oil to the cam surface tends to be insufficient, and high cam surface lubrication performance is required to prevent seizure of the cam body.

On the other hand, if a forced lubrication structure is added to the cam surface for forcibly supplying hydraulic oil from the outside, it is disadvantageous in terms of cost and causes an increase in the number of parts that can cause failures and an increase in the size of the device.

The present invention was made in view of the above-mentioned problems, and aims to develop a rotational difference-sensitive differential limiting device that can improve the lubrication performance of the cam surface without increasing the number of parts or increasing the size. Make it a common issue.

(Means for Solving the Problems) In order to solve the above problems, a rotation difference sensitive differential limiting device according to claim 1 is arranged in a differential housing in which hydraulic oil is sealed and connected to a drive input side. a differential case, a binion shaft supported by the differential case, a binion rotatably supported via the binion shaft,
a differential means having a pair of side gears meshing with the binion; and a differential limiter assembled in a built-in state in the middle of a driving force transmission path leading to an output shaft connected to the side gears in order to exhibit a differential limiter function. In the rotation difference sensitive differential limiting device, the differential limiting means includes a housing member connected to one of the pair of side gears, a rotor member connected to the other side gear, a cam surface formed on the inner surface of the housing member; a radially arranged cam body provided on the rotor member that reciprocates in the radial direction while circumferentially contacting the cam surface due to relative rotation; a plurality of fluid chambers whose volumes change without change; an orifice member provided in a fluid path connecting each fluid chamber and the accumulator chamber; and a first hole formed at a radial position corresponding to the cam body of the differential case and housing member. A cam surface lubrication structure constituted by a notch surface formed in the outer circumferential surface of the cylinder in which the first oil hole, the second oil hole, and the second oil hole of the housing member are provided, and a hydraulic oil sealing chamber surrounded by the inner surface of the cylinder of the differential case. It is characterized by being a means having the following.

Further, in the rotation difference sensitive differential limiting device according to claim 2,
The differential limiting means is characterized by having a cam surface lubricating oil hole formed in a side portion of the housing member in an inclined state toward the cam surface.

(Function) When using a rotation difference sensitive differential limiting device, when there is no relative rotation between the two output shafts, there is no reciprocating movement of the cam body and no change in volume of the fluid chamber occurs. No dynamic limiting torque occurs.

At this time, since relative rotation does not occur between the housing member and the rotor member, the problem of generation of friction heat due to friction welding between the cam body and the cam surface does not occur.

When relative rotation occurs between both output shafts, the cam body that is in contact with the cam surface reciprocates in the radial direction due to this relative rotation, and during this reciprocating movement, when the volume of the fluid chamber is reduced by moving toward the center of the rotation axis. The pressure inside the fluid chamber increases due to the flow resistance caused by the orifice member, and the fluid pressure obtained by multiplying this generated fluid pressure and the pressure receiving area of the cam body becomes a force that presses the cam body against the cam surface, and this pressing is caused by a differential force. This is the limiting torque.

When this relative rotation occurs, relative rotation also occurs between the housing member and the rotor member, so that frictional pressure heat is generated on the cam surface.

However, when this relative rotation occurs, the cam surface is lubricated as described below.

First, in the rotation difference sensitive differential limiting device according to claim 1,
Due to the relative rotation between the differential case and the housing member, in a positional relationship where the hydraulic oil sealing chamber and the first oil hole opened in the differential case communicate with each other, the hydraulic oil sealed in the differential housing operates from the first oil hole. In the positional relationship in which the hydraulic oil is introduced into the oil sealing chamber, and then the hydraulic oil sealing chamber and the first oil hole are blocked, the hydraulic oil sealed in the hydraulic oil sealing chamber flows from the second oil hole of the housing member to the inner surface of the housing member. is supplied to the cam surface formed on the cam surface.

In other words, when relative rotation occurs, the cam surface lubrication structure repeatedly introduces hydraulic oil into the hydraulic oil sealing chamber and supplies hydraulic oil from the hydraulic oil sealing chamber, and seals the hydraulic oil that attempts to escape toward the outer circumference due to centrifugal force within the differential case. This ensures the lubrication performance of the cam surface and suppresses the generation of heat due to frictional pressure.

On the other hand, in the rotation difference sensitive differential limiting device according to claim 2,
The hydraulic oil sealed in the differential housing is radiated toward the cam surface from the cam surface lubricating oil hole opened in the side of the housing member due to the action of rotational centrifugal force, and the lubrication performance of the cam surface is improved. is ensured, and friction welding heat generation is suppressed.

(Example) Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

First, the configuration of the embodiment will be explained.

FIG. 1 is a diagram showing a rotation difference sensitive differential limiting device according to an embodiment in which the cam surface lubrication structure according to claim 1 and the cam surface lubrication oil hole according to claim 2 are combined, and the differential function is A rotation difference-sensitive differential limiting means 2 that exhibits a differential limiting function is assembled in the differential mechanism 1 that exhibits a built-in differential limiting function.

The differential means 1 is disposed within a differential housing 5 in which hydraulic oil is sealed. a differential case 10 to which a driving force is input via a drive pionion 3 and a ring gear 4; a binion 12 rotatably supported by the differential case 10 via a binion shaft 11; It is provided with a pair of side gears 13, 14 meshing with each other, and two output shafts 15.16 connected to the side gears 13.14.

The driving force is equally distributed to the output shafts 15 and 16 when no relative rotation occurs, and when relative rotation occurs, the driving force is transmitted by the differential limiting torque by the rotation difference sensitive differential limiting means 2. is transmitted from the high rotation side to the low rotation side.

As shown in FIGS. 1 and 2, the rotational difference-sensitive differential limiting means 2 is configured to connect one output shaft 1 of the output shafts 15 and 16.
5, a cam housing 20 (housing member) on which a side gear 14 is formed, a cam surface 21 formed on the inner surface of the cam housing 20, and the other output shaft 16 on which a side gear 13 is spline-coupled.
a rotor 30 (rotor member) spline-coupled to the
A radially arranged driving piston 40 (cam body) provided on the rotor 30 and reciprocating in the radial direction while circumferentially contacting the cam surface 21 due to relative rotation, and a cylinder whose volume changes as the driving piston 40 reciprocates. Room 50 (
an inclined balance oil passage 60 (fluid passage) that communicates the cylinder chambers 50 and 50, which are arranged opposite to each other and whose volume changes in the same phase;
, a regulator oil passage 80 communicating between the accumulator chamber 70 and each cylinder chamber 50, and an orifice 90 (orifice member) provided in the axial branch oil passage 61 heading from the inclined balance oil passage 60 to the accumulator chamber 70. It is equipped with

The cam housing 20 is provided via a cam housing cover 22 spline-coupled to the output shaft 15, and has a cam surface 21 formed on its inner surface and a side gear 14 formed on its side surface. That is, output shaft 1
5, the cam housing cover 22, the cam housing 20, and the side gear 14 are integrally rotating members.

The rotor 30 is spline-coupled to the output shaft 16 and inserted into the cam surface 21 of the cam housing 20, and is arranged at six positions facing the cam surface 21 at equal intervals in the radial direction. A cylinder hole 31 is formed in.

The driving piston 40 is connected to the cylinder hole 31.
On the other hand, six cam members are provided in an oil-tight state by a seal ring 41, and the circumferential surface with the cam surface 21 is formed into a spherical surface to ensure smooth contact movement and high Hertzian contact stress.

The cylinder chamber 50 is formed between the cylinder hole 31 and the driving piston 40 so that the chamber volume changes depending on the stroke position of the piston 40.

The inclined balance oil passage 60 is connected to the driving piston 4.
The cylinder chamber 50 faces two surfaces A and B perpendicular to the rotary shaft, which are within the range of the diameter of the cylinder hole 31 in which the cylinder hole 31 is provided and which are set at an interval in the rotor axial direction that is narrower than this hole diameter. One inclined balance oil passage 60 is formed with the position where one chamber bottom surface and surface A intersect as a cylinder chamber opening 60a, and the position where the other chamber bottom surface and surface B intersect as a cylinder chamber opening 60b, In addition, three inclined balance oil passages 60 are formed in the rotor axial width N so as not to interfere with each other.

The accumulator chamber 70 is a chamber that temporarily stores and releases hydraulic oil to absorb an increase or decrease in the amount of oil, and includes an accumulator piston 71 that is provided in an oil-tight manner on the inner surface of the cylinder portion 32 of the rotor 30 so as to be able to reciprocate and slide. , the piston 71
and a spring 73 interposed between the spring retainer 72 and the spring retainer 72.

The accumulator piston 71 is provided with a piston seal 74, and the cylinder portion 32 of the rotor 30 corresponding to the position where the piston seal 74 is provided is provided with:
A plurality of relief holes 75 are opened in the radial direction, so that the accumulator chamber 70 exceeds the set pressure and the accumulator piston 7
1 moves to the right in the drawing, the relief hole 75 communicates with the accumulator chamber 70 and the hydraulic oil is transferred to the cam housing 20.
and a relief valve function for discharging to the inlet part 20a between the rotor 30 and the rotor 30.

The regulator oil passage 80 is an oil passage provided for adjusting the oil pressure of the cylinder chamber 50, and communicates the accumulator chamber 70 and each cylinder chamber 50 via one-way valves 81, so that the driving piston 40 can be moved out. When the cylinder chamber pressure becomes lower than the accumulator chamber pressure during radial stroke and the one-way valve 81 opens, pressurized hydraulic oil is supplied from the accumulator chamber 70 to each cylinder chamber 50.

The orifice 90 is formed in each of the three axially branched oil passages 61 extending from the inclined balance oil passage 60 to the accumulator chamber 70, and has a flow passage cross-sectional area larger than that of the cylinder chambers 50 and 50 of the two opposing cylinders. One orifice 90 provides flow resistance to the hydraulic oil.

The cam surface lubrication structure 100 includes a differential case 10 and a cam housing 2, as shown in FIG.
A first oil hole 101 and a second oil hole 102 are formed in four holes at equiangular positions in the radial direction corresponding to the driving piston 40 of No. 0.
The cam housing 20 includes a notch 20b formed on the outer cylindrical surface where the second oil hole 102 is provided, and four hydraulic oil chambers 103 surrounded by the cylindrical inner surface of the differential case 10.

Moreover, as the cam surface lubricating oil hole 200, a first cam surface lubricating oil hole 201 and a second cam surface lubricating oil hole 202 are opened,
The first cam surface lubricating oil hole 201 is located in the cam housing cover 2.
The second cam surface lubricating oil hole 202 is formed on the side of the cam housing 20 at a position facing the oil chamber 10a formed in the differential case 10 and is inclined toward the cam surface 21. A hole is formed at the root position of the side gear 14 in an inclined state toward the cam surface 21.

Next, the operation of the embodiment will be explained.

(a) When driving in a straight line on a dry asphalt road at low to medium speeds, when there is no rotational speed difference between the left and right shafts connected to the output shaft 15.16, the case cover 2 and rotor 3
0, and the driving piston 40 does not reciprocate in the radial direction, so the differential case 10
The engine driving force input from the output shafts 15 and 16 is equally distributed to the output shafts 15 and 16.

At this time, the cam housing 20 and the rotor 30
Since there is no relative rotation between the cam surface 21 of the cam housing 20 and the driving piston 40 of the rotor 30, the problem of generation of friction heat due to friction welding between the cam surface 21 of the cam housing 20 and the driving piston 40 of the rotor 30 does not occur.

On the other hand, even when there is no relative rotation between the left and right axes, when driving straight on a highway at high speed, the output shaft 15.1
Centrifugal force acts on the driving piston 40 provided on the rotor 30, which rotates at high speed as the rotor 6 rotates.
The driving piston 40 is pressed against the cam surface 21 by this centrifugal force, and a differential limiting torque is generated.

Therefore, when traveling straight at high speed, the differential limiting function is exerted to some extent, and the stability of straight traveling at high speed on expressways can be improved.

(b) When relative rotation occurs When a difference in rotational speed occurs between the left and right shafts connected to the output shaft 15° 16 when driving on a rough road or when one wheel is stuck, the case cover 20 and rotor 3o also rotate relative to each other. occurs, and due to this relative rotation, the driving piston 4o in circumferential contact with the cam surface 21 reciprocates in the radial direction, and when attempting to reduce the volume of the cylinder chamber 50 by moving toward the center of the rotation axis during this reciprocating movement, the orifice The pressure inside the cylinder chamber 5o increases due to the flow resistance caused by the flow restriction by the piston 90, and the hydraulic pressure obtained by multiplying this generated hydraulic pressure and the pressure receiving area of the piston 40 becomes a force that presses the driving piston 4o against the cam surface 21, and this pressure The applied force acts as a differential limiting torque, and the differential is limited so that the distribution of driving force is smaller on the high-speed rotation side and larger on the low-speed rotation side.

That is, the differential limiting torque characteristic of the embodiment device shows a characteristic in which the differential limiting torque TLSD increases in a quadratic function curve with respect to the left and right wheel rotational speed difference ΔN8L, as shown by the solid line characteristic in FIG.

Note that when the vehicle speed V is high, such as when driving at high speed, a transmission torque of 8T is added due to the centrifugal force applied to the driving piston 40, as shown by the dotted line characteristic in FIG. 6, corresponding to the magnitude of the vehicle speed V. It shows the characteristics that have been

When this relative rotation occurs, the cam housing 20
The cam surface 21 of the rotor 30 and the driving piston 40 of the rotor 30
Since relative rotation occurs between the two, frictional pressure heat is generated on the cam surface 21.

However, when this relative rotation occurs, the cam surface 21 is lubricated as described below.

First, due to the relative rotation between the differential case 10 and the cam housing 20, as shown in FIG. The hydraulic oil sealed in the housing 5 is introduced from the first oil hole 101 to the hydraulic oil sealing chamber 103, and then, in the positional relationship where the hydraulic oil sealing chamber 103 and the first oil hole 101 are blocked, the hydraulic oil sealing chamber 101 is introduced into the hydraulic oil sealing chamber 103. The hydraulic oil sealed in 103 flows into the second oil hole 1 of the cam housing 20.
02 to the cam surface 21 formed on the inner surface of the cam housing 20.

That is, when relative rotation occurs, the cam surface lubrication structure 100 introduces hydraulic oil into the hydraulic oil sealing chamber 103 and closes the hydraulic oil sealing chamber 1.
By repeating the supply of hydraulic oil from 03, the hydraulic oil that tries to escape toward the outer circumference due to centrifugal force is contained within the differential case 10, ensuring the lubrication performance of the cam surface 21 and suppressing the generation of heat due to frictional pressure. .

On the other hand, regarding the cam surface lubricating oil hole 200, as shown in FIG.
The first cam surface lubricating oil hole 201 and the second
This shows the action of radiating the oil from the cam surface lubricating oil hole 202 toward the cam surface 21, ensuring the lubricating performance of the cam surface 21 and suppressing the generation of heat due to frictional pressure.

Further, when the cam surface lubrication structure 100 and the cam surface lubrication oil hole 200 are used together as in the embodiment, not only the hydraulic oil introduced from the first oil hole 101 but also the cam surface lubrication oil hole 200
A synergistic effect is shown in that the hydraulic oil emitted from zero due to the rotational centrifugal force is also confined within the differential case 10 by the cam surface lubrication structure 100, ensuring high lubrication performance of the cam surface 21 and suppressing the generation of heat due to frictional pressure. A cooling effect will be exerted.

As explained above, the rotational difference sensitive differential limiting device of the embodiment provides the following effects.

■ Since the cam surface lubrication structure 100 and the cam surface lubrication oil hole 200 are provided, in the case of the cam surface lubrication structure 100, the cam surface lubrication oil hole is In the case of 200, cam surface 21 from the inside
By supplying hydraulic oil to the cam surface 21, the lubrication performance of the cam surface 21 can be improved without increasing the number of parts or increasing the size.

Furthermore, a cam surface lubrication structure 100 and a cam surface lubrication oil hole 200
Since not only the hydraulic oil introduced from the first oil hole 101 but also the hydraulic oil emitted from the cam surface lubricating oil hole 200 by the action of rotational centrifugal force is also used in conjunction with the cam surface lubrication structure 100, the differential case 10, exhibiting a synergistic effect of being confined within the cam surface 21, ensuring high lubrication performance of the cam surface 21 and exhibiting a high cooling effect that suppresses the generation of heat due to frictional pressure.

■ Piston seal 74 of accumulator piston 71
The cylinder portion 3 of the rotor 30 corresponding to the position where the
2, by simply opening a plurality of relief holes 75 in the radial direction, a relief valve function that utilizes the stroke action of the accumulator piston 71 allows hydraulic oil to be supplied to the inlet part 2.
Since the discharge is made to 0a, it is possible to improve the lubrication performance of the inlet part 20a between the cam housing 20 and the rotor 30 without increasing the number of parts or increasing the size. Lubricating performance is exhibited in a corresponding relationship with heat, and even when a high relative rotational speed difference ΔNRL continues for a long time, seizure of the cam housing 20 and rotor 30 due to frictional contact heat is prevented.

■ The fluid path that communicates the cylinder chambers 50 and 50 whose volume changes in the same phase is an inclined balance oil path 60, and the position that intersects two planes A and B perpendicular to the rotation axis is the cylinder chamber opening 6.
0a and 60b, the three inclined balance oil passages 60 fit within the rotor axial width N without interfering with each other, so the inner part of the rotor 30 where the oil passages are formed has two parallel oil passages. Rotor axial width N approximately equal to the axial width to be formed
Therefore, it is possible to achieve a smaller and more compact rotational difference sensitive differential limiting device.

For example, the number of driving pistons 40 may be increased due to a design change, and along with this, the inclined balance oil passage 6 may be increased.
Even if there is an increase in the number of 0's, the width can be handled without increasing the axial width of the rotor.

■ Although the regulator oil passage 80 is formed in a position overlapping with surface B, it is formed with an offset in the direction orthogonal to the rotation axis with respect to the inclined balance oil passage 60, so that it does not rotate with the inclined balance oil passage 60. Axial overflow is avoided, and the rotor axial width N is reduced by the regulator oil passage 80.
The expansion of can be prevented.

That is, due to the synergistic effect with the effect (2) above, the axial width N of the rotor can be set narrowly, and the rotation difference sensitive differential limiting device can be made smaller and more compact.

■ Since one orifice 90 is provided for the inclined balance oil passage 60 that communicates the cylinder chambers 50 and 50 of two opposing cylinders, the differential limit is the same as when one orifice is provided for one cylinder chamber. The cross-sectional area of the orifice 90 can be made larger than the cross-sectional area of the orifice when obtaining torque characteristics, and as a result, the influence of contamination (dust, etc.) can be avoided.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, it can be applied to a center differential that allows differential movement between the front and rear wheels instead of the left and right axes.

Further, in the embodiment, a preferable example was shown in which a cam surface lubrication structure and a cam surface lubrication oil hole were used in combination, but it goes without saying that the cam surface lubrication performance can be sufficiently improved even when either one is used. , included in the present invention.

Further, in the embodiment, a fixed orifice is shown as the orifice member, but for example, when high relative rotation continues for a long time, the orifice opening may be completely closed by sensing the hydraulic oil temperature. Alternatively, a variable orifice or the like may be used in which the opening degree of the orifice is gradually changed depending on the relative rotational speed, fluid chamber pressure, etc.

(Effects of the Invention) As described above, in the rotation difference sensitive differential limiting device according to claim 1, the differential limiting means is located at a radial position corresponding to the cam body of the differential case and the housing member. The housing member is comprised of a first oil hole and a second oil hole opened in the housing member, a notch formed in the outer peripheral surface of the cylinder in which the second oil hole of the housing member is provided, and a hydraulic oil sealing chamber surrounded by the inner surface of the cylinder of the differential case. Since this means has a cam surface lubrication structure, the effect is that the lubrication performance of the cam surface can be improved without increasing the number of parts or increasing the size by supplying hydraulic oil to the cam surface from the outside. can get.

Further, in the rotation difference sensitive differential limiting device according to claim 2, the differential limiting means includes a cam surface lubricating oil hole formed in a side portion of the housing member in an inclined state toward the cam surface. Because of this means, the effect of supplying hydraulic oil to the cam surface from the inside can improve the lubrication performance of the cam surface without increasing the number of parts or increasing the size.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional plan view showing a rotation difference sensitive differential limiting device according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional front view showing the rotation difference sensitive differential limiting device taken along line I-I in FIG. 1. , Fig. 3 and Fig. 4 are diagrams for explaining the cam surface lubrication effect by the cam surface lubrication structure, Fig. 5 is a diagram for explaining the cam surface lubrication effect by the cam surface lubricating oil hole, and Fig. 6 is a differential limiting torque characteristic diagram. . 1...Differential means 2...Rotation difference sensitive differential limiting means 5...Differential housing 10...Differential case 11...Pinion shaft 12...Binion 13.14...Side gear 15 .16...Output shaft 20...Cam housing (housing member) 21...
・Cam surface 30...Rotor (○-ta member) 32...Cylinder part 40...Driving piston (cam body) 50...-
Cylinder chamber (fluid chamber) 60... Inclined balance oil passage (fluid passage) 70... Accumulator chamber 80... Regulator oil passage 90... Orifice (orifice member) 100...
Cam surface lubrication structure 101...first oil hole 102...second oil hole 103...hydraulic oil sealing chamber 200...cam surface lubrication oil hole 201...first cam surface lubrication oil hole 202...・Second cam surface lubricating oil hole

Claims (1)

[Scope of Claims] 1) A differential case disposed in a differential housing in which hydraulic oil is sealed and connected to the drive input side, a pinion shaft supported by the differential case, and a pinion shaft. a differential means having a pinion rotatably supported through the differential means, and a pair of side gears meshing with the pinion; and a differential limiting function provided in the middle of a driving force transmission path leading to an output shaft connected to the side gears. In the rotation difference sensitive differential limiting device, the differential limiting device includes a differential limiting means that is assembled in a built-in state to achieve the desired effect, wherein the differential limiting device includes a housing member connected to one of the pair of side gears; a rotor member connected to the other side gear; a cam surface formed on the inner surface of the housing member; and a radially arranged cam provided on the rotor member that reciprocates in the radial direction while circumferentially contacting the cam surface due to relative rotation. a plurality of fluid chambers whose volume changes as the cam body reciprocates, an orifice member provided in a fluid path connecting each fluid chamber and an accumulator chamber, and a cam body of the differential case and housing member. A first oil hole and a second oil hole that are opened at opposing radial positions, and an operation that is surrounded by a cutout surface formed on the outer peripheral surface of the cylinder where the second oil hole of the housing member is provided, and the inner surface of the cylinder of the differential case. A rotation difference sensitive differential limiting device characterized by having a cam surface lubrication structure constituted by an oil-filled chamber. 2) A differential case arranged in a differential housing in which hydraulic oil is sealed and connected to the drive input side, a pinion shaft supported by the differential case, and a pinion shaft rotatably supported via the pinion shaft. A differential means having a pinion and a pair of side gears that mesh with the pinion, and a differential means that is assembled in a built-in state in the middle of a driving force transmission path leading to an output shaft connected to the side gear to exhibit a differential limiting function. In the rotation difference sensitive differential limiting device, the differential limiting device includes a housing member connected to one side gear of the pair of side gears, and a rotor connected to the other side gear. a cam surface formed on the inner surface of the housing member; a radially arranged cam body that is provided on the rotor member and reciprocates in the radial direction while making circumferential contact with the cam surface due to relative rotation; a plurality of fluid chambers whose volume changes with movement; an orifice member provided in a fluid path connecting each fluid chamber and an accumulator chamber; A rotation difference sensitive differential limiting device characterized by having a cam surface lubricating oil hole.