JPH06185581A - Differential gear - Google Patents

Abstract

PURPOSE:To provide a small and light differential gear which is designed to reduce a differential limit force during reversing of a vehicle to a value lower than that during advancing and prevent the occurrence of interference between an engine brake and an ABS. CONSTITUTION:A differential gear 7 comprises two helical pinion gears 63 and 65, making a pair, contained in the containing holes 59 and 61 of a differential gear case 21; and a pair of helical side gears 37 and 39 geared with the respective helical pinion gears. The side gears are caused to push each other by means of a thrust force when a vehicle is driven frontward and the pinion gears are engaged with each other at the outside in the axial direction of an engaging part with the side gear.

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 in a vehicle.

[0002]

2. Description of the Related Art FIG. 1 is disclosed in JP-A-49-104328.
0-like helical gear type differential device 20
1 is described. This is provided with a pair of side gears 203 and 205, each of which is connected to the wheel side, a plurality of sets of pinion gears 207 and 209, and a differential case 211 that houses them. Pinion gears 207 and 209
Has a tooth tip slidably supported in a housing hole 213 of the differential case 211. The pinion gears 207 and 209 mesh with the side gears 203 and 205, respectively, and the shaft of the meshing portion with the side gears 203 and 205. They mesh with each other inside the direction. Also, each side gear 203, 205
A spacer 215 is arranged between them.

[0003]

In this differential device 201, the side gears 203 and 205 are abutted against the spacer 215 by the thrust force due to the meshing of the gears, and the differential torque is obtained by the friction torque. Since the pinion gears 207 and 209 mesh with each other on the inner side in the axial direction as described above, the spacer 215 has the side gear 20.
It is also necessary to hit 3,205.

However, in order to reduce the size and weight of the device, if the wide and heavy spacer 215 is removed, the side gear 20 is removed.
In order to abut the 3,205, they must be extended inward in the axial direction, and the size and weight cannot be reduced. or,
Depending on the rotation direction of the differential case 211, the differential limiting force when the vehicle travels forward becomes greater than the differential limiting force, and, for example, the engine brake interferes with the antilock brake system (ABS).

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a small and lightweight differential device which can reduce the differential limiting force when the vehicle is moving backward and when it is moving forward.

[0006]

SUMMARY OF THE INVENTION A differential device according to the present invention comprises a differential case which is rotationally driven by a driving force of an engine, a pair of helical side gears each connected to a wheel side, and a sliding hole in a differential case. A pair of helical pinion gears that are movably housed are provided, and the side gears press against each other by thrust force when the differential case is driven by the engine in the rotational direction when the vehicle is moving forward, and the pinion gears mesh with the side gears separately. It is characterized in that they are in mesh with each other and these side gears mesh with each other axially outside the meshing portion.

[0007]

Since each pinion gear is meshed with the side gear on the axially outer side of the meshing portion, the side gear can be abutted without using the spacer as in the conventional example and without extending the side gear. It is small and lightweight.

Further, when the differential case is driven by the engine and the vehicle moves forward, the thrust forces of the side gears give each side gear a twist angle in a direction in which the thrust forces oppose each other. With such a configuration, as described below, when a differential occurs, a larger differential limiting force is obtained when the vehicle is moving forward by the friction torque due to the thrust force difference between the grip side of the side gear and the idling side than when the vehicle is moving backward. Therefore, when the engine brake is operating, the torque direction is the same when the vehicle is moving backward, and the differential limiting force becomes small.
Interference with the BS is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIGS. FIG. 1 shows the differential device of this embodiment,
FIG. 7 shows a power system of a vehicle using this differential device. The left and right directions are the left and right directions in this vehicle and FIGS.

As shown in FIG. 7, this power system includes an engine 1, a transmission 3, a propeller shaft 5, a rear differential 7 (a differential device of the embodiment arranged on the rear wheel side), left and right rear axles 9, 11. Left and right rear wheels 13,1
5, the left and right front wheels 17, 19 and the like. In the rear differential 7, the differential case 21 is the differential carrier 23.
The ring gear 25, which is rotatably disposed inside and is fixed to the differential case 21, meshes with the drive pinion gear 27. The drive pinion gear 27 is formed integrally with a drive pinion shaft 29 connected to the propeller shaft 5 side. In this way, the driving force of the engine 1 rotationally drives the differential case 21 from the transmission 3 via the propeller shaft 5.

As shown in FIG. 1, the differential case 21 has a main body 3
1 and a cover 35 fixed to the main body 31 with bolts 33. Inside the left and right side gears 37, 39
(Helical side gear) is arranged. The side gears 37, 39 are supported by the differential case 21 by shaft supporting portions 41, 43 provided between the side gears 37, 39, and the opposite ends are centered by the shaft supporting portions 45 provided between the side gears 37, 39. . Left and right side gears 37,
Reference numeral 39 is spline-coupled to the left and right rear axles 9 and 11, respectively, and is fixed in the axial direction by circlips 47 and 47. A steel washer 49 is arranged between the side gears 37 and 39, and washers 51 and 51 having a small friction coefficient are provided between the side gears 37 and 39 and the differential case 21.
Are arranged. The differential case 21 has openings 53, 5
5, 57 are provided, and the oil enclosed in the differential carrier 23 flows in and out to lubricate the inside.

As shown in FIG. 2, four sets of housing holes 59 and 61 are formed in the main body 31 on the outer sides of the side gears 37 and 39 in the radial direction. The housing holes 59 and 61 respectively have long and short pinion gears 63 and 65 ( Helical pinion gear) is slidably and rotatably housed. The pinion gears 63 and 65 are arranged in the circumferential direction in reverse for each adjacent pair. An arrow 67 in FIG. 3 indicates the leftward direction of the vehicle, and the long pinion gear 63 is composed of left and right gear parts 69 and 71, and a shaft part 73 that connects these parts and has a small diameter to avoid interference with the side gear 37. ing. As shown in FIGS. 1 and 3, the left gear portion 69 meshes with the left end portion of the short pinion gear 65, and the right gear portion 71 meshes with the right side gear 39. Further, as shown in FIG. 1, the right end portion of the pinion gear 65 meshes with the left side gear 73.

As described above, since the pinion gears 63 and 65 mesh with each other on the left side (outside in the axial direction) of the meshing portion with the side gear 37.39, the side gears 37 and 39 differ from the conventional example of FIG. No spacer is required for abutting against each other, and it is not necessary to extend the side gears 37 and 39 inward. Therefore, it is smaller and lighter.

The driving force of the engine 1 for rotating the differential case 21 is from the pinion gears 63 and 65 to the side gear 3.
It is distributed to the left and right rear wheels 13 and 15 via 7, 39, and when a driving resistance difference is generated between the rear wheels, the pinion gears 63 and 65 are rotated and are differentially distributed to the left and right sides. During torque transmission,
The pinion gears 63 and 65 are pressed against the housing holes 59 and 61 by the reaction force of engagement with the side gears 37 and 39, and the differential torque is limited by the friction torque. This differential limiting force is equal when the vehicle is moving forward and when the vehicle is moving backward. Further, as shown in FIG. 2, since the pinion gears 63 and 65 of each set are arranged in the circumferential direction in the reverse order, the pressing forces of the pinion gears 37 and 39 against the differential case 21 are equal regardless of the forward and backward movement and the turning direction. A uniform differential limiting force can be obtained between the rear wheels 13 and 15.

As shown in FIG. 3, each gear is a helical gear, and the side gears 37 and 39 are provided with opposite twist angles. The arrow 75 indicates the rotation direction of the differential case 21 when the vehicle moves forward by the driving force of the engine. Therefore, when the vehicle moves forward, the side gears 37, 39 engage the steel washer 49 with the thrust force meshing with the pinion gears 63, 65. Through each other as shown in Figure 4,
When the vehicle is moving backward (the direction of torque is the same as when using the engine brake while moving forward), it is pressed against the differential case 21 side as shown in FIG.

FIG. 4 and FIG. 5 show a state in which the right rear wheel 15 idles on a bad road or the like. Fh indicates the thrust force of the right side gear 39 on the idling side, and Fl indicates the thrust force of the left side gear 37 on the grip side. Here Fl: F
Let h = 10: 1. R2 and R1 respectively indicate the friction diameter between the side gears 37 and 39 via the steel washer 49 and the friction diameter between the side gears 37 and 39 and the differential case 21 via the washer 51. The friction coefficient of each friction surface is μ.

Assuming that R1 = R2 = R, as shown in FIG. 5, when the vehicle is in reverse, Fl and Fh face outward, and the side gear 3
The rotation of the side gears 37, 39 is braked by the friction torques T1 = F1.multidot..multidot.R / 2 and T2 = Fh.multidot..multidot.R / 2 generated between the gears 7, 39 and the differential case 21, respectively, and the differential limiting force is obtained. To be Further, as shown in FIG. 4, when the vehicle is moving forward, Fl,
Fh is directed inward, T1 equal to the above occurs in each side gear between the side gears 37, 39 and the steel washer 49, and the force (Fl-Fh) is applied to the differential case 2 via the steel washer 49 and the side gear 39.
The friction torque of T3 = (F1-Fh) .multidot..mu.R / 2 is obtained between the side gear 39 and the differential case 21. In the example of FIGS. 4 and 5, the ratio (T1 + T1 + T3) :( T1 + T2) = 2 of the differential limiting force when the vehicle is moving forward and when the vehicle is moving backward.
It will be 9:11.

As described above, the differential limiting force of the rear differential 7 can be increased when the vehicle is moving forward and can be decreased when the vehicle is moving backward. Further, the friction coefficient of the steel washer 49 is larger than the friction coefficient of the washer 51, and the friction diameter is also R2> R1, so the difference in the differential limiting force is further increased.

FIG. 6 is a graph of the differential limiting characteristic of the rear differential 7, graphs 77 and 79 are characteristics when the vehicle is moving forward, and graphs 81 and 83 are characteristics when moving backward. Further, the graphs 77 and 81 show the rear differential 7 when the right rear wheel 15 idles.
Shows the axial torque sent to the left rear wheel 13 by the differential limiting force, and graphs 79 and 83 show the axial torque sent to the right rear wheel 15 when the left rear wheel 13 runs idle.

As described above, the differential limiting force due to the meshing reaction force is equal between the left and right rear wheels 13 and 15 depending on the arrangement order of the pinion gears 63 and 65.
Also, the graphs 81 and 83 are symmetrical with respect to the straight line 85 having the gradient 1, and the differential limiting force due to the thrust force is large at the time of forward movement and small at the time of backward movement.
Is the angle β of the graphs 81 and 83 with respect to the straight line 85.
Greater than

Therefore, in the vehicle of FIG. 7, the forward differential stability is improved by the large differential limiting force of the rear differential 7 when moving forward, and even if one of the rear wheels spins, a large driving force is sent to the other rear wheel. The ability to drive on rough roads is improved. Further, when the engine brake is used, the direction of the torque is the same as that when the vehicle is moving backward, and the differential limiting force is small, so that the interference with the ABS is prevented.

Next, the second embodiment will be described with reference to FIGS. The differential device 87 of this embodiment is
The structure of the pinion gear is different from that of the first embodiment,
Members having the same functions as those of the first embodiment are designated by the same reference numerals. The left-right direction is the left-right direction in FIG.

The differential case 89 comprises a main body 91 and a cover 35 fixed to the main body 91 with bolts 33, and side gears 37 and 39 are arranged inside. The main body 91 has storage holes 93, 9 on the outside of the side gears 37, 39 in the radial direction.
5, the pinion gears 97 and 99 (helical pinion gears) are slidably housed. The pinion gears 97 and 99 are arranged in the circumferential direction in reverse for each pair of adjacent gears.

The arrow 101 in FIG. 9 indicates the left direction in FIG.
The pinion gears 97 and 99 are respectively on the left gear portion 10
3, 105, right gear parts 107, 109, and small-diameter shaft parts 111, 113 connecting these parts. or,
The gear parts 105 and 107 are respectively gear parts 103 and 109.
Longer. Each pinion gear 97, 99 has a short gear portion 1
03 meshes with the left end portion of the long gear portion 105, and the short gear portion 109 meshes with the right end portion of the long gear portion 107, so that they are connected to each other on both outer sides in the axial direction. Further, the side gear 37 is connected to the pinion gear 99 by meshing with the right end portion of the gear portion 105, and the side gear 39 is connected to the gear portion 1.
It is connected to the pinion gear 97 by meshing with the left end portion of 07. The side plate 115 is attached to the differential case 21 by the retaining ring 1.
The pinion gears 97 and 99 are fixed at 17, and are opposed to the right end portions of the pinion gears 97 and 99.

As described above, since the pinion gears 97 and 99 mesh with each other on both sides in the axial direction of the meshing portion with the side gears 37 and 39, extension of the side gears 37 and 39 and spacers are unnecessary, and the size and weight are small. is there.

Each gear is a helical gear, and an arrow 119 in FIG. 9 indicates a differential case 21 when the vehicle is driven forward.
Shows the rotation direction of. At this time, the side gear 37,
Numeral 39 pushes each other through the steel washer 49 by the thrust force meshing with the pinion gears 97 and 99, and when the vehicle is in reverse, the thrust forces are opposite to each other.
It is pressed against the differential case 21 via.

With such a gear structure, the differential device 87 of this embodiment can obtain a large differential limiting force when the vehicle is moving forward, as well as the first embodiment, and can prevent the interference between the engine brake and the ABS.

[0028]

According to the differential device of the present invention, since a pair of pinion gears for connecting the side gears are meshed with each other on the axially outer side of the meshing portion with the side gears, the side gears can be arranged close to each other, and a spacer or a side gear for abutting the side gears can be arranged. It is not necessary to extend and can be made compact and lightweight. Further, since the respective gears are configured to press against the helical gears and the respective side gears press each other when the vehicle moves forward, the differential limiting force at the time of reverse driving becomes smaller than that at the time of moving forward, and the interference between the engine brake and the ABS can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a perspective view of a pinion gear used in the first embodiment.

FIG. 4 is an operation diagram of the first embodiment.

FIG. 5 is an operation diagram of the first embodiment.

FIG. 6 is a graph showing the differential limiting characteristic of the first embodiment.

FIG. 7 is a skeleton mechanism diagram showing a power system of a vehicle using the first embodiment.

FIG. 8 is a sectional view of a second embodiment.

FIG. 9 is a perspective view of a pinion gear used in the second embodiment.

FIG. 10 is a sectional view of a conventional example.

[Explanation of symbols]

7 Rear differential (differential gear) 21,89 Differential case 37,39 Side gear (helical side gear) 59,61,93,95 Storage hole 63,65,97,99 Pinion gear (helical pinion gear) 87 Differential gear

Claims (1)

[Claims] 1. A differential case which is rotationally driven by the drive of an engine, a pair of helical side gears each connected to a wheel side, and a pair of two helical pinion gears slidably housed in a housing hole of a differential case. The side gears press against each other by thrust force when the differential case is driven by the engine in the rotational direction when the vehicle is moving forward, and the pinion gears mesh with the side gears separately and the shafts of the meshing parts with these side gears. A differential device characterized in that they mesh with each other on the outside in the direction.