JPH0942416A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent from making stress concentration, gears partial touch, etc., hold the gears properly engaged, improve their durability and produce large differential limiting force. SOLUTION: A device is provided with output side gears 15, 17 which are arranged on a differential case 3 rotating driven by an engine, four pair of pinion gears 43, 45 having fist gear parts 47, 53 which are arranged in parallel in an axial direction on the diameter direction outer side of the gears 15, 17 and be engaged independently with the gears 15, 17 and second gear parts 49, 55 which are engaged with each other, and housing holes 39, 41 for housing the gears 43, 45 in a slidingly rotatable manner. The axis part 51 which is a tooth bottom diameter and less and a dividing part 57 are arranged between the first gear part 47, 53 and the second gear parts 49, 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device used for a vehicle.

[0002]

2. Description of the Related Art FIG. 3 is disclosed in JP-A-49-104328.
Such a differential device 201 is described.

The differential device 201 includes a differential case 203, side gears 205 and 207 on the output side, and side gears 205 and 2 arranged in parallel on the outer side in the radial direction thereof.
A plurality of pairs of pinion gears 209, 211,
Pinion gears 209, 21 formed on the differential case 203
Storage holes 213 and 2 for storing 1 in a freely slidable manner
15 and so on.

The pinion gears 209 and 211 are respectively engaged with the side gears 205 and 207 by a first gear portion 217 which meshes with the side gears 205 and 207, respectively.
219 and the second gear portions 221 and 223 meshing with each other are integrally formed. The twist angles of the gear portions 217 and 221 of the pinion gear 209 are in the same direction, and the twist angles of the gear portions 219 and 223 of the pinion gear 211 are also in the same direction.

The driving force of the engine causes the differential case 203 to rotate, causing the pinion gears 209 and 211 to move to the side gear 2.
When the driving resistance difference is transmitted to the wheels via 07 and 205 and a driving resistance difference is generated between the wheels, the driving force is differentially distributed to the respective wheels by the rotation of the pinion gears 209 and 211.

[0006]

For example, the side gear 207 and the pinion gear 21 that mesh with the pinion gear 209.
When the second gear portion 223 of No. 1 receives torque, the central portion 2 of the tooth 2
29 and the end portions 225 and 227 mesh with each other, and the end portions 225 and 227 having low rigidity are bent in the twisting direction.

However, the central portion 229 of the pinion gear 209 facing the end portions 225, 227 has a high rigidity in the twisting direction and cannot absorb the bending of the end portions 225, 227. Therefore, stress concentration occurs near the end portions 225, 227 and the central portion 229, and the pinion gear 209
Pitching (a phenomenon in which flakes are exfoliated from the surface of the metal under load), scoring (a phenomenon in which a tooth tip of a gear meshes with a tooth tip of a mating gear), and the like occur at a portion of a diagonal line 231 in FIG.

Further, since the central portion 229 of the pinion gear 209 has a high rigidity, the flexural deformation of the end portions 225 and 227 caused by the twisting is absorbed by the flexure of the tooth trace of the gear portion, and finally the gear portion 229 is absorbed. May damage the tooth traces of. Such a problem occurs in the pinion gear 211 as in the pinion gear 209.

Further, in a device in which the pinion gears 209 and 211 are arranged in parallel in the axial direction like the differential device 201, the side gear and the other pinion gear have a meshing reaction force in the opposite direction to the pinion gear arranged in the rotational direction. Hang up. Since the pinion gear that rotates in advance changes between forward traveling and reverse traveling of the vehicle, the meshing reaction force in the opposite direction is applied to both pinion gears, and the generated overturning moments 235 and 23 are generated.
7 (illustrated on the pinion gear 209 as an example), each pinion gear 209, 211 tilts with respect to the rotation center axis.

Due to this fall, each pinion gear 209,
Partial contact occurs between 211 and the housing holes 213 and 215, causing uneven wear and seizure, and the meshing of the gears worsens.

In addition to this, the differential device 20
In the apparatus having the configuration as described in 1, the differential limiting force is obtained by the meshing thrust force of the helical gear, for example, the frictional resistance generated between the side gears 205 and 207. However, in the differential device 201, the side gear 2
A space is provided between 05 and 207, and the cross pin 239 and the spacer 241 are arranged in this space, so that the frictional resistance between the side gears 205 and 207 cannot be fully utilized.

For example, when the side gears 207, 205 are extended inward in order to bring the side gears 205, 207 into direct contact with each other to fully utilize the frictional resistance, interference between the extended portions and the pinion gears 209, 211 is prevented. Therefore, the extension portion has to have a small diameter, and a large differential limiting force cannot be obtained.

Therefore, the present invention provides a differential device which prevents stress concentration and partial contact of gears, maintains good gear meshing, improves durability, and obtains a large differential limiting force. To aim.

[0014]

A differential device according to a first aspect of the present invention is a differential device which is rotationally driven by a driving force of an engine, a pair of output side helical side gears rotatably supported in the differential case, and a pair of output side gears. At least a pair of helical pinion gears, which are arranged radially outward in parallel with each other in the axial direction, have a side gear and a first gear portion that meshes with each other, and a second gear portion that meshes with each other, and each pinion gear formed in the differential case is slidably rotatably accommodated. The pinion gear has a first gear portion and a second gear portion that are integrally formed with each other and have a twist angle in the same direction, and between the first gear portion and the second gear portion. It is characterized in that a divided portion having a diameter of a tooth root or less is provided.

A differential device according to a second aspect of the present invention is the differential device according to the first aspect, in which a thrust washer is arranged between the side gear and the differential case, and the outer peripheral portion of the thrust washer penetrates into the split portion within a range that does not interfere with the pinion gear. .

According to another aspect of the differential device of the present invention, the second gear portion of the pinion gear meshes with at least one axial outer side of both side gears, and these second gear portions are supported in the receiving hole over the entire surface other than the meshing portions of each other. The differential device according to claim 1 or 2.

In the differential device of each claim, frictional resistance is generated by the meshing reaction force received by the pinion gear and the meshing thrust force of each gear, and the frictional resistance provides a torque-sensitive differential limiting function.

According to another aspect of the present invention, in the differential device, the pinion gear is provided with a divided portion having a root diameter or less to divide the first gear portion and the second gear portion, and the divided portion increases rigidity of the pinion gear between the gear portions. Moderately relaxed.

Therefore, the torsional bending of the end portion of the side gear and the end portion of the second gear portion is absorbed by the torsional bending in the split portion of the pinion gear that meshes with them, so that pitching and scoring are prevented. . Further, since the bending of the tooth trace, which has been repeatedly generated at each end of the mating gear, is absorbed by the bending of the divided portion, the tooth trace is not damaged.

Further, even if the pinion gear receives a tipping moment due to a reaction force of meshing in the opposite direction, the tipping moment is absorbed by the bending of the split portion, so that the pinion gear and the housing hole are partially hit and biased by the hit. Wear and seizure are prevented, and the meshing of each gear is maintained well. Thus, the durability of the differential device is greatly improved.

A differential device according to a second aspect of the present invention is the differential device according to the first aspect, wherein a thrust washer is arranged between the side gear and the differential case, and an outer peripheral portion of the thrust washer is inserted into the split portion within a range not interfering with the pinion gear. As in the differential device of claim 1, since the rigidity of the pinion gear is moderately relaxed by the dividing portion, pitching, scoring, damage to the mating gear, uneven wear and seizure with the storage hole, The deterioration of meshing of gears is prevented, and the durability of the differential gear is greatly improved.

In addition to this, since the diameter of the thrust washer of the side gear is increased by utilizing the divided portion of the pinion gear, the frictional resistance due to the meshing thrust force and the differential limiting force are strengthened to that extent, and the thrust washer slides. The increase in the moving area prevents seizure of the side gear.

A differential device according to a third aspect is the differential device according to the first or second aspect, in which the second gear portion of the pinion gear is meshed with at least one axial outer side of both side gears and these second gear portions are engaged with each other. The bearing is supported by the receiving hole on the entire surface other than the meshing portion with each other, and like the differential device according to claim 1 or 2, the rigidity of the pinion gear is moderately relaxed, resulting in damage to the pitching, scoring, or the mating gear. Uneven wear and seizure with the storage hole, deterioration of meshing of gears, etc. are prevented, and durability of the differential device is significantly improved.

In addition to this, since the second gear portion is securely supported in the accommodating hole, the pinion gears are prevented from inclining and the core is deviated, and the meshing with the mating gear is improved.
Uneven wear and seizure with the storage hole are more effectively prevented. In addition to such effects, for example, according to the configuration of claim 2, a large frictional resistance and a differential limiting force due to the meshing thrust force of the side gears can be obtained.

Further, since the second gear portion of each pinion gear is meshed with the outer side of both side gears in the axial direction, it is not necessary to provide a space between both side gears for avoiding interference with the second gear portion. Both side gears can be brought into contact with each other to fully utilize the frictional resistance, and the differential limiting force can be strengthened.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This embodiment has the features of claims 1, 2 and 3, and FIG. 1 shows a differential device 1 of this embodiment.
Is shown. Note that the left and right directions are the left and right directions in FIG. 1, and the members and the like without reference numerals are not shown.

As shown in FIG. 1, the differential case 3 of the differential device 1 is constructed by fixing a casing body 5 and a cover 7 with bolts 9. A ring gear is fixed to the differential case 3, and the ring gear meshes with the output gear of the power transmission system. In this way, the differential case 3 is rotationally driven by the driving force of the engine via the power transmission system.

The differential device 1 is arranged inside the differential carrier, and the boss portions 11 and 1 of the differential case 3 are arranged.
Reference numeral 3 is supported on a differential carrier via a bearing. The differential carrier is provided with an oil sump. The lower part of the differential device 1 is immersed in the oil sump in a stationary state, and repels the oil from the oil sump when rotated.

Inside the differential case 3, output side gears 15 and 17 each composed of a helical gear are arranged.

Hollow boss 1 of each side gear 15, 17
The bearings 9 and 21 are rotatably supported by bearings 23 and 25 of the differential case 3. Further, thrust blocks 31 are arranged on the large diameter portions 27 and 29 formed inside the boss portions 19 and 21 so as to straddle their inner circumferences, and the side gear 1
Centering is performed while supporting the free ends of 5 and 17.

The thrust block 31 is provided with two chamfered portions 32 parallel to each other, and an oil reservoir is formed between the chamfered portions 32 and the large diameter portions 27, 29.

The boss portion 19 of the side gear 15 is spline-connected to the output shaft of one wheel, and the boss portion 21 of the side gear 17 is spline-connected to the output shaft of the other wheel.
These output shafts are attached to each other via a thrust block 31.

A thrust washer 33 is arranged between the side gear 15 and the differential case 3, a thrust washer 35 is arranged between the side gear 17 and the differential case 3, and is located between the side gears 15 and 17 (outer peripheral side of the thrust block 31). Is provided with a thrust washer 37.

The differential case 3 has long and short storage holes 39, 41.
Are formed. Four sets of the storage holes 39 and 41 are arranged in the circumferential direction, and the storage holes 39 and 41 are arranged in parallel in the axial direction. Long and short pinion gears 43 and 45 formed of helical gears are slidably and rotatably housed in the housing holes 39 and 41, respectively.

The long pinion gear 43 includes the first and second gear portions 47 and 49 and a small-diameter shaft portion 51 connecting them.
The first gear part 47 meshes with the right side gear 17. Also, the short pinion gear 45
Is composed of first and second gear portions 53 and 55 and a split portion 57 formed therebetween, the first gear portion 53 meshes with the left side gear 15, and the second gear portion 55 includes the pinion gear 43. Meshes with the second gear portion 49 of the.

The shaft portion 51 and the dividing portion 57 are formed by the gear portions 47,
It has a smaller diameter than 49, 53, 55.
The pinion gear 43 includes the shaft portion 51 and the gear portions 47 and 49.
The pinion gear 45 is divided into gear parts 53 and 55 by a dividing part 57.

As shown in FIG. 2, the thrust washer 33
Recesses 59 and 61 are formed on the outer periphery of the recesses 59 and 61 for avoiding interference with the pinion gears 43 and 45.
The protrusions 63 and 65 formed between 61 penetrate the shaft part 51 and the division part 57, respectively, as shown in FIG.
In FIG. 2, r2 is the radius of the thrust washer 33 provided with the convex portions 63 and 65, which is larger than the thrust washer of the radius r1 in the conventional example in which the split portion is not formed in the pinion gear, and the sliding area is increased. are doing.

The driving force of the engine for rotating the differential case 3 is from the pinion gears 43 and 45 to the side gears 17 and 1.
It is distributed to each output shaft via 5. Further, for example, when a driving resistance difference occurs between wheels during traveling on a rough road, each pinion gear 4
Due to the rotation of 3, 45, the driving force of the engine is differentially distributed to each wheel side.

During transmission of torque, each pinion gear 43, 4
The tooth tip of No. 5 is pressed against the wall surfaces of the storage holes 39, 41 by the reaction force of meshing with the side gears 17, 15, and frictional resistance is generated. Further, due to the meshing thrust force of the helical gear, frictional resistance is generated between the pinion gears 43 and 45 and the end faces of the housing holes 39 and 41, and the thrust washer 33 is provided between the side gear 15 and the differential case 3 via the thrust washer 33. Friction resistance is generated between the side gear 17 and the differential case 3 via 35, and between the side gears 15 and 17 via the thrust washer 37. These frictional resistances provide a torque sensitive differential limiting function.

As shown in FIG. 1, the differential case 3 has an opening 6
7, 69 are provided, and spiral oil grooves 71, 73 are formed on the inner circumferences of the boss portions 11, 13.

When the differential device 1 is stationary, the oil immersed in the openings 67, 69 and the oil grooves 71, 73 flows into the inside of the differential case 3, and the storage hole 39,
It is supplied to 41 and the meshing portion of each gear and lubricates them.

When the differential device 1 is rotated, the oil splashed up from the oil reservoir and rebounded by the inner wall of the differential carrier flows into the differential case 3 through the openings 67, 69 and the oil grooves 71, 73 and lubricates the inside. In addition, oil is forcibly supplied to each thrust washer 33, 35, 37 by centrifugal force from the oil reservoir formed by the chamfered portion 32 of the thrust block 31, and the side gear 1
5 and 17 and the differential case 3 are prevented from seizing, and this oil lubricates the meshing portions of the storage holes 39 and 41 and the gears. In this way, the differential device 1 is configured.

In the differential device 1, as described above, each pinion gear 43, 45 is provided with each gear part 47, 49 ,.
A shaft portion 51 and a split portion 57 for splitting 53 and 55, respectively, are provided, and the shaft portion 51 and the split portion 57 moderately reduce the rigidity, particularly the rigidity in the twisting direction.

Therefore, in the pinion gear 43, the torsional flexure at the end portion of the side gear 17 and the torsional flexure at the end portion of the pinion gear 45 (second gear portion 55) are transmitted to the shaft portion 51 during torque transmission.
The pinion gear 45 is absorbed by the torsional flexure of the pinion gear 45.
The twisting and bending of the end portion of the third (second gear portion 49) is the split portion 57.
It is absorbed by the twisting and bending of.

As a result, pitching and scoring are prevented by the pinion gears 43 and 45, and the deflection of the tooth trace, which has been repeatedly generated at each end of the mating gear, is conventionally prevented.
Since it is absorbed by the bending of the shaft portion 51 and the division portion 57, damage to the tooth trace is prevented.

Further, even when the pinion gears 43 and 45 are subjected to the meshing reaction force in the opposite directions, this overturning moment is absorbed by the bending of the shaft portion 51 and the dividing portion 57.
Partial contact with the storage holes 39, 41 and uneven wear and seizure due to this contact are prevented, and good meshing of the gears is maintained. In this way, the durability of the differential device 1 is significantly improved.

Further, as described above, by providing the convex portions 63 and 65, the thrust washer 33 has a large diameter, the contact area is increased as compared with the thrust washer of the conventional example, and other thrust washers are used. Since the diameters of 35 and 37 are correspondingly increased, the side gears 15 and 17, the differential case 3 and the side gear 1 due to the meshing thrust force.
The frictional resistance between 5 and 17 and the differential limiting force are enhanced accordingly. Further, seizure between the differential case 3, the side gears 15 and 17, and the side gears 15 and 17 is prevented by increasing the sliding area of the thrust washers 33, 35 and 37.

Further, since the second gear portions 49 and 55 of the pinion gears 43 and 45 are meshed with each other on the outer side in the axial direction of the side gears 15 and 17, the second gear portions 49 and 55 are accommodated on the entire surfaces other than the meshing portions. The holes 39 and 41 can support the pinion gears 43 and 45, so that the support state of the pinion gears 43 and 45 is improved, and tilting and center runout are prevented. Therefore,
The meshing with the mating gear is improved, and uneven wear and seizure between the housing holes 39 and 41 are effectively prevented.

Further, since the second gear portions 49 and 55 are meshed with each other on the axially outer sides of the side gears 15 and 17 in this manner, the space provided between the side gears 15 and 17 in the conventional example of FIG. 3 is reduced. Since it becomes unnecessary, by bringing the side gears 15 and 17 into contact with each other via the thrust washer 37, it is possible to fully utilize the frictional resistance between the side gears 15 and 17 to strengthen the differential limiting force.

A vehicle equipped with the differential device 1 has a torque-sensitive differential limiting function, which stabilizes the behavior of the vehicle body when a large torque is applied, such as at the time of starting or accelerating. Due to the effect of improving the durability of the device 1, excellent maneuverability and runnability can be obtained for a long time.

In the structure of the third aspect, each pinion gear may be provided with two second gear portions, and these may be meshed with each other on both axial sides of both side gears. Also in this case, according to the present invention, a split portion is provided between the first gear portion and the second gear portion to moderately reduce the rigidity, so that pitching, scoring, breakage of the mating gear, and a gap between the storage holes. Uneven wear and seizure are prevented, good gear meshing is maintained, and the durability of the differential device is greatly improved.

Further, the differential device of the present invention includes a front differential (a differential device arranged on the front wheel side axle), a rear differential (a differential device arranged on the rear wheel side axle), and a center differential (engine). Can be used for a differential device that distributes the driving force of the vehicle to the front wheel side and the rear wheel side).

[0053]

According to the differential device of the first aspect of the present invention, the pinion gear is provided with a divided portion having a diameter of the tooth bottom or less to divide the first gear portion and the second gear portion, and the divided portion forms the pinion gear between the gear portions. The rigidity of the is moderately relaxed.

Therefore, the torsional flexure at each end of the second gear portion of the side gear and the pinion gear and the flexure of the tooth trace that repeatedly occurs at each end of these mating gears are twisted at the pinion gear side where they mesh. It is absorbed by flexure, preventing pitching, scoring, and damage to tooth traces.

Further, since the overturning moment applied to the pinion gear is also absorbed by the bending of the divided portion, partial contact with the storage hole and uneven wear and seizure due to this contact are prevented, and the meshing of each gear is good. Kept in. Thus, the durability of the differential device is greatly improved.

A differential device according to a second aspect of the present invention is the differential device according to the first aspect, wherein the outer peripheral portion of the thrust washer disposed between the side gear and the differential case is inserted into the split portion within a range not interfering with the pinion gear. The same effect as the differential device of claim 1 is obtained.

In addition to this, since the diameter of the thrust washer of the side gear is increased by utilizing the divided portion of the pinion gear, the frictional resistance due to the meshing thrust force and the differential limiting force are strengthened to that extent, and the thrust washer slides. The increase in the moving area prevents seizure of the side gear.

A differential device according to a third aspect of the present invention is the differential device according to the first or second aspect, in which the second gear portion of the pinion gear is meshed with at least one axial outer side of both side gears and the meshing portion of the second gear portion. The entire surface other than the above is supported by the storage hole, and claim 1
Or, the same effect as the differential device of 2 is obtained.

In addition to this, since the second gear portion is securely supported in the storage hole to prevent the pinion gear from falling and center runout, the meshing with the mating gear is improved, and the deviation between the gear and the storage hole is improved. Wear and seizure are effectively prevented. Furthermore, the second
By engaging the gear parts on the outer side in the axial direction of the both side gears, the both side gears can be brought into contact with each other and the frictional resistance can be fully utilized to enhance the differential limiting force.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

2 is a plan view of a thrust washer used in the embodiment of FIG. 1. FIG.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Differential Device 3 Differential Case 15 and 17 Output Side Gear 33 Thrust Washer 39 and 41 Storage Hole 43 and 45 Pinion Gear 47 and 53 First Gear Part 49 and 55 Second Gear Part 51 Shaft Part (Split Part) 57 Split Part

Claims (3)

[Claims] 1. A differential case which is rotationally driven by a driving force of an engine, a pair of output side helical side gears which are rotatably supported inside the differential case, and a side gear which is arranged radially outside of the side gears in an axial direction. And at least a pair of helical pinion gears each having a first gear portion meshing with each other and a second gear portion meshing with each other,
And a storage hole formed in the differential case for slidably and rotatably storing the respective pinion gears, wherein the first gear portion and the second gear portion of the pinion gear are integrally molded and have a twist angle in the same direction, A differential device characterized in that a split portion having a root diameter or less is provided between the first gear portion and the second gear portion. 2. The differential device according to claim 1, wherein a thrust washer is arranged between the side gear and the differential case, and an outer peripheral portion of the thrust washer penetrates the split portion within a range not interfering with the pinion gear. 3. A second gear portion of the pinion gear meshes with at least one axial outer side of both side gears, and these second gear portions are supported in the storage hole over the entire surface other than the meshing portions of each other. 2 differential devices.