JPH0826931B2 - Differential device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a differential device having a differential lock mechanism.

(Prior Art) Japanese Patent Publication No. 57-4536 discloses a diff lock device. As shown in FIG. 3, this device is a differential limiting device of a differential device in which a pair of differential side gears 105, 105 are meshed with a differential pinion 103 which is rotatably supported by a differential case 101 which rotates by inputting torque. A multi-plate clutch 107 for limiting or stopping the differential between the differential case 101 and the side gear 105, a hydraulic actuator 109 for pressing and fastening the same, and a cylinder device 111 for applying hydraulic pressure thereto.

However, since the pressing force of the multi-plate clutch 107 is input to the meshing portion between the diff side gear 105 and the diff pinion 103, the backlash thereof changes (narrows) and the meshing is adversely affected.

In addition, there is a diff lock device that connects a diff case and a differential gear with a dog clutch, but as shown in FIG.
If the clutch teeth 113, 115 are straight or have an inverse tapered shape with a thicker tooth tip than the tooth root, it is difficult to engage at the time of meshing because of the narrow spacing between the tooth flanks. Further, in the case of the clutch teeth 115, thrust force in the engagement direction due to the taper is applied to this and it is difficult to disengage. In addition, when the tooth ends are in mesh with each other, the corners are likely to be chipped and the tooth root is weak because the thickness is insufficient.

(Problems to be Solved by the Invention) Accordingly, the present invention provides a differential device in which the differential lock mechanism does not affect the meshing of the differential gears, the differential lock operation and the release operation are smooth, and the strength of the cam portion is large. To aim.

[Means for Solving the Problems] (Means for Solving the Problems) A differential device according to the present invention includes a differential case that rotates by inputting a torque, a pinion gear that is rotatably supported by the differential case, and a pair of gears that mesh with the pinion gear. The first provided between the side gear and the differential case
And a second cam portion provided between the counter gear portion of the side gear and engaged and disengaged while being constantly engaged with the cam portion of the first cam, and the first and second cams. parts has a pressure angle of engagement theta ₁ and theta ₂ each provide a thrust force of the disengagement direction of the clutch member, when the meshing pressure angle between the pinion and side gears and _{θ 3, θ 3 ≧ θ 1} > It is characterized in that it is θ ₂ .

(Operation) When torque is input and the differential case rotates, this rotation is caused by the rotation of the pinion gear via the pinion gear.
Differentially distributed to each side gear.

The clutch member is moved to stop the differential distribution function to the side gears that connect the differential case and the side gears so that they cannot rotate relative to each other, and the differential lock state is established, so that the torque distribution ratios to them are equal. When these connections are released, the differential lock is released and the differential distribution function is restored.

If there is a rotation difference between the differential case and the side gear when the tips of the second cam (engagement side) start to mesh, θ ₁
Since> θ ₂ , the difference between the thrust forces of θ ₁ (first cam portion) and θ ₂ (second cam portion) acts on the clutch member in the engaging direction in addition to the movement operation force. Engage the cam part of. Further, in the engaged state of the cam portion, since θ ₃ ≧ θ ₁ , the thrust force of the side gear due to the meshing pressure angle θ ₃ with the pinion gear is always larger than the thrust force difference from the clutch member. Therefore, the influence on the backlash is small, and the meshing between the side gear and the pinion gear is maintained normally.

(Embodiment) An embodiment will be described with reference to FIGS. 1 and 2. This embodiment is used in the power system of the vehicle shown in FIG. Less than,
The left-right direction is the left-right direction in Fig. 1, and the upper part is the second direction.
It corresponds to the front (upper) of the vehicle in the figure. Further, members without numbers are not shown.

The vehicle shown in FIG. 2 has an engine 1, a transmission 3,
Direction changing gear set 5, propeller shaft 7, rear differential 9
(Differential device of this embodiment), rear axle 11,1
3, left and right rear wheels 15,17, left and right front wheels 19,21, etc.

As shown in FIG. 1, the differential case 23 of the rear differential 9 is rotatably supported by the differential carrier 29 by bearings 25 and 27. A drive pinion shaft 33 having a front end connected to the propeller shaft 7 side and a drive pinion gear 31 integrally formed at the rear end is rotatably supported on the differential carrier 29. A ring gear 35 meshing with the gear 31 is fixed to the differential case 23 with bolts 37. In this way, the differential case 23 is rotationally driven by the driving force from the engine 1.

A pinion shaft 41 is supported in an axial groove 39 provided on the inner circumference of the differential case 23 so as to be axially movable and integrally rotatable with the differential case 23. Pinion shaft
A pinion gear 43 is rotatably supported by 41, and a pair of side gears 45, 47 are meshed with the left and right sides thereof at a meshing pressure angle θ ₃ . The left side gear 45 is splined to the left rear axle 11, and the right side gear 47 is splined to the right rear axle 13. Further, the rear axle 11 is provided at the left end of the differential carrier 29.
Is attached to the right end of the axle tube 49 of the rear axle 13.

Therefore, the differential case 23 is driven by the driving force from the engine 1.
When the pinion gear 43 rotates, this rotation passes through the pinion shaft 41 and the pinion gear 43, and by the rotation of the pinion gear 43,
The side gears 45, 47 are differentially distributed to the left and right rear wheels 15, 17 side.

In the axial space between the right side gear 47 and the differential case 23, a ring-shaped clutch member 51 is provided around the outer periphery of the differential case 23.
It is arranged so as to be movable in the axial direction while being supported on the inner circumference. A first cam portion 53 is provided between the clutch member 51 and the side wall of the differential case 23, and the clutch member 51 and the side gears are provided.
A second cam portion 55 is provided between the anti-gear portion 47. The clutch member 51 moves in the axial direction while always meshing with the cam portion 53 to engage and disengage the cam portion 55. Therefore, when the clutch member 51 moves to the left as shown in the lower half of FIG. 1 (a), the side gear 47 and the differential case 23 are connected to each other such that they cannot rotate relative to each other, and the differential distribution function is stopped to enter the differential lock state. .
Also, when moving to the right as in the upper half of the figure, the side gear 47
The relative rotation of the differential case 23 is enabled, and the differential lock is released. As shown in FIG. 1B, the meshing angles θ ₁ and θ ₂ of the cams 53 and 55 are θ ₁ > θ ₂ .

A retaining ring 57 is attached to the inner circumference of the differential case 23,
Between the 57 and the clutch member 51, a return spring for urging the clutch member 51 to the right to release the engagement of the cam portion 55.
59 are arranged.

The pressing member 61 includes a plurality of axial arms 63 arranged in the circumferential direction.
And a ring-shaped base portion 65 connecting these right end portions, the arm 63 penetrates the differential case 23, and the left end thereof is in contact with the clutch member 51.

The diff carrier 29 has a ring 75 with a U-shaped cross section that is prevented from rotating.
The bolt 67 is fastened together with a lock 73 of the lock nut 71 by a bolt 69. Inside the ring 75, a ring 77 having a U-shaped cross section is fixed so that the concave portions of the ring 77 face each other, and a ring-shaped diaphragm 79 is fixed to the fixed portion of the ring 77 at the inner and outer peripheral edges in an airtight manner. There is. The left end of the ring 77, through which the pressing member 81 penetrates, abuts the pressing member 61 and the right end of the diaphragm 77
It is placed in contact with 79. Diaphragm 79 and ring
Air pressure is supplied to the pressure chamber 83 formed between 75 from the air pump 87 via the pipe line 85. When the air pressure is supplied, the pressure chamber 83 expands and the clutch member 5 is pressed through the pressing members 81 and 61.
Move 1 to the left diff lock side. Thus, the air actuator 89 is configured. Such a pressure supply operation can be manually performed from the driver's seat or automatically according to steering conditions or road surface conditions. A retaining ring 91 is attached to the outer periphery of the differential case 23, and washers 93 are disposed between the ring 75 and the differential case 23 and the retaining ring 91.

In this way, when the clutch member 51 is moved to the left and the second cam portion 55 starts meshing, the differential case 23
If there is a rotation difference between the side gear 47 and the side gear 47, each cam part 53,55
At, a thrust force for pushing back the clutch member 51 is generated. At this time, since θ ₁ > θ ₂ , the thrust force from the cam portion 53 is larger than the thrust force from the cam portion 55,
The thrust force corresponding to the difference acts to the left (the diff lock side). Since this thrust force is applied to the pressing force of the actuator 89, the cam portion 55 smoothly engages and the clutch member
51 is held stable in this position.

Further, since θ ₃ ≧ θ ₁ , the rightward thrust force exerted on the side gear 47 by meshing with the pinion gear 43 is always larger than the thrust force difference. Therefore, the influence on the backlash is minimal, and in addition, the pinion shaft 41 has a groove.
Since the pinion gear 43 and the left and right side gears 45, 47 are always equal in backlash because they can move along 39, their meshing is normally maintained. The differential case 23
Sliding between the pressing side and the actuator 89 side is performed at the contact portion of the pressing members 61 and 81.

When the pressure supply to the actuator 89 is stopped, the clutch member
51 is moved to the right by the urging force of the return spring 59, and the engagement of the cam portion 55 is released. This urging force is set to be larger than the thrust force generated by the cam portion 53.

As shown in FIG. 1 (b), the corner portions 95 and 97 of the teeth of the cam portion 55 are obtuse angles, so they are not chipped even in the initial stage of meshing in which the force concentrates on these portions. In addition, the teeth of the cam portions 53 and 55 have wide roots, and therefore have high strength. Further, as described above, the engagement in the cam portion 55 is smooth, and the engagement pressure angle θ ₂ also facilitates the disengagement due to the thrust force in the backward direction. When the diff lock is released, the rear wheels 15 and 17 can be differentially rotated, and the vehicle can smoothly turn. When the diff lock state is set, this differential rotation is stopped, the straight running stability is improved, and the transmission driving force to the rear wheels 15 and 17 becomes equal,
Only one rear wheel slips on a bad road and the running performance is not lost.

[Effects of the Invention] As described above, in the differential device of the present invention, the differential lock mechanism does not affect the meshing of the differential gears, the differential lock operation and release are smooth, and the strength of the cam portion is large.

[Brief description of drawings]

FIG. 1A is a sectional view of one embodiment, and FIG. 1B is A of FIG.
-A sectional view, FIG. 2 is a skeleton mechanism diagram showing a power system of a vehicle using this embodiment, FIG. 3 is a sectional view of a conventional example, and FIG. 4 is a partial sectional view of another conventional example. 23 ... Differential case 43 ... Pinion gear 45, 47 ... Side gear 51 ... Clutch member 53, 55 ... Cam section

Claims (1)

[Claims] 1. A differential case which is rotated by inputting torque,
The pinion gear rotatably supported by the differential case, the pair of side gears meshing with the pinion gear, and the first cam portion provided between the differential case and the first cam portion are constantly engaged with each other to receive the axial movement operation and to counteract the side gear. And a clutch member that engages and disengages with a second cam portion that is provided between the gear portion and the gear portion, and the first and second cam portions apply a thrust force in the engaging and disengaging direction to the clutch member, respectively θ ₁ and It has a meshing pressure angle theta _2, the the meshing pressure angle between the pinion and side gears and theta _3, differential device which is a _{θ 3 ≧ θ 1> θ 2} .