JP2886737B2 - Differential device - Google Patents

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 Differential devices 201 and 203 as shown in FIGS. 7 and 8 are described in Japanese Utility Model Laid-Open No. 63-78746 and Japanese Utility Model Laid-Open No. 62-172842, respectively.

The differential gears 201 and 203 include bevel gear type differential gear mechanisms 207 and 209, viscous couplings 211 and 213 for limiting a differential, and a multi-plate clutch 215.
217 respectively. The viscous couplings 211 and 213 are speed-sensitive differential limiting means that generate a greater differential limiting force as the differential rotational speed increases. or,
The multi-plate clutches 215 and 217 are
9, 221 are fastened by a meshing reaction force to the pinion gears 223, 225. The meshing reaction force increases as the transmission torque of the differential gear mechanisms 207, 209 increases, so that the multi-plate clutches 215, 217 are torque-sensitive. This is a differential limiting means.

[0004]

As shown in FIG. 7, in a differential 201, a left side gear 219 in the figure is connected to a left axle 233 via a hub 231 and a right side gear 23
5 is connected to the right axle 237. Multiple disc clutch 2
Reference numeral 15 denotes an SH type (S: shaft, H: housing) disposed between the hub 231 and the differential case 239 (housing). 8, in the differential 203, the multiple disc clutch 217 is disposed between the right side gear 221 and the differential case 241 in the figure, and the viscous coupling 213 is disposed between the left side gear 243 and the differential case 241. Are arranged, and all are SH types.

In the differential gear 201, the multi-plate clutch 2
The transfer ratios (R _t ) of the left and right axles 233 and 237 generated by 15 are R _tL and R _tR , respectively.

[0006]

(Equation 1) f _L : friction torque generated in the multi-plate clutch 215 according to the input torque and transmitted to the left axle 233 side.

F _R : multi-plate clutch 2 according to input torque
15 and transmitted to the right axle 237 side.

Here, since f _L = 0,

(Equation 2) Therefore, R _tL ≠ R _{tR and a} one-sided effect occurs.

In this case, in FIG.
The driving force indicated by the thick arrow 249 is input to 237, and the driving force indicated by the broken arrow 251 is applied to the right axle 237 to be strengthened.

As described above, when the differential limiting means is arranged in the SH type, the differential limiting force becomes unequal on the left and right sides, and a one-sided effect occurs.

FIG. 9 is a graph showing a differential limiting characteristic of the differential device 201. The vertical axis indicates the shaft torque transmitted to the right wheel when the left wheel is idling, and the horizontal axis indicates the shaft torque transmitted to the left wheel when the right wheel is idling. Shaft torque. Graphs 253 and 255 show the right-axis torque and the left-axis torque by the multiple disc clutch 215, respectively, which are asymmetric with respect to the straight line 257 at 45 °, and indicate that the right-axis torque is larger than the left-axis torque as described above. ing. The gradient with respect to the horizontal axis of the graph 253 and the gradient with respect to the vertical axis of the graph 255 are referred to as a transfer ratio (R _t ).

Accordingly, the characteristics of the entire differential 201 are graphs 259 and 261 obtained by equally applying the differential limiting force by the viscous coupling 211 to the graphs 253 and 255.

FIG. 10 is a graph showing the differential limiting characteristics of the differential 203, and graphs 263 and 265 show the characteristics of the multi-plate clutch 217. Since the multi-plate clutch 217 is arranged on the right side gear 221 side on the SH type, the left shaft torque is larger than the right shaft torque. Therefore, the differential 203
The overall characteristics are graphs 267 and 269 obtained by adding the differential limiting force of the viscous coupling 213 to graphs 263 and 265.
And is asymmetric with respect to the straight line 257.

As described above, there has hitherto not been provided any differential device having the characteristics of the torque-sensitive type and the speed-sensitive type and having uniform differential limiting characteristics on one side and the other side.

Therefore, the present invention comprises a torque-sensitive type and a speed-sensitive type differential limiting means, so that the differential limiting characteristics are equal when the differential gear on one side is idle and when the differential gear on the other side is idle. It is an object of the present invention to provide a differential device that can obtain the following.

[0016]

SUMMARY OF THE INVENTION A differential gear according to the present invention comprises a pair of differential gears connected to respective power transmission shafts, meshing with these differential gears, meshing with each other, and paralleling the differential gears. A connecting gear comprising a pair of pinion gears arranged on a shaft and connecting the differential gears so as to be rotatable differentially, and each of these gears is rotatably supported, and the pair of tooth top surfaces is slidably and rotatable in a storage hole. A differential gear mechanism having a differential case accommodated in the differential gear mechanism, and when a driving rotation difference occurs in one or the other power transmission shaft in a state where the differential case is rotationally driven in the differential gear mechanism, a frictional resistance between the pinion gear and the differential case is reduced. A torque-sensitive differential limiting means that limits the differential in response and the driving forces sent to the other or one of the power transmission shafts are equal to each other,
A speed-sensitive differential limiting means for limiting a differential in response to a differential rotational speed between a cylindrical member connected to one of the differential gears and a hub connected to the other differential gear; At least one pinion gear of the pair of pinion gears has one end positioned axially on one side of the differential case and the other end axially abutting the other side of the differential case via the cylindrical member. Characterized by being positioned on the side.

[0017]

The driving force input from the differential case to the differential gear mechanism is distributed to each power transmission shaft via the connecting gear and the differential gear. Further, the differential gear rotates differentially according to the driving resistance difference on each power transmission shaft side, and the driving force is differentially distributed to each power transmission shaft side.

In this differential gear mechanism, a speed-sensitive type differential limiting means is arranged in an SS type, and the torque-sensitive type differential limiting means is provided with another type even if any of the power transmission shafts runs idle. The driving force transmitted to the power transmission shaft on the ground side is equal to each other, and uniform differential limiting characteristics can be obtained on one side and the other side. Since a speed-sensitive differential limiting force is equally applied to this characteristic, the overall differential limiting characteristic is equal between one side and the other side, and there is no one-sided effect that degrades maneuverability.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIGS. FIG. 1 shows a differential device of this embodiment,
FIG. 4 shows a power system of a vehicle using the differential device. The left and right directions are the left and right directions in this vehicle and FIG. 1, and members and the like without reference numerals are not shown.

[0020] As shown in FIG.
It comprises a transmission 3, a propeller shaft 5, a rear differential 7 (differential device of FIG. 1 disposed on the rear wheel side), rear axles 9, 11, left and right rear wheels 13, 15, and left and right front wheels 17, 19 and the like. . In the rear differential 7, the differential case 21 is rotatably disposed in a differential carrier 23, and a ring gear 25 fixed to the differential case 21 meshes with a 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. Thus, the driving force of the engine 1 is transmitted to the rear differential 7 via the transmission 3 and the propeller shaft 5 to drive the differential case 21 to rotate.

As shown in FIG. 1, the differential case 21 includes a main body 31.
And a cover 35 fixed to the main body 31 with screws 33, and a pair of side gears 37 and 39 (differential gears) are arranged inside. A left hub 41 is disposed on the left side of the side gear 37, and the flange portion 43, the cylindrical member 45, the right flange 47, and the left side gear 37 are integrated by welding. Hub 41 is cover 3
5 is rotatably supported by a shaft support 49, and a washer 51 is arranged between the flange 43 and the cover 35. The right side gear 39 is formed on the right hub 53, and the hub 53 is connected to the shaft support 55 of the main body 31.
It is rotatably supported by. The left rear axle 9 is splined to the left hub 41 and prevented from falling off by a retaining ring 57, and the right rear axle 11 is splined to the right hub 53 and prevented from falling off by a retaining ring 59. I have.

The main body 31 is provided with a long storage hole 61 and a short storage hole circumferentially adjacent to the storage hole 61 in a direction parallel to the axis. A pinion gear 63 is provided in the storage hole 61.
(Connecting gear) is slidably and rotatably accommodated, and a short pinion gear (connecting gear) is slidably and rotatably accommodated in the short storage hole, and each is rotatably supported on the outer periphery of the tooth tip.

The long pinion gear 63 includes the left and right gear portions 6.
5 and 67 and a shaft portion 69 connecting these members. The shaft portion 69 has a small diameter in order to avoid interference with the right side gear 39. The left gear 65 meshes with the left side gear 37, and the right gear 67 meshes with the right end of the short pinion gear. The short pinion gear meshes with the right side gear 39 at the left end. A thrust washer 71 and retaining rings 73, 73 are mounted on the main body 31 to prevent the long and short pinion gears from falling off. Thus, the differential gear mechanism 75 is configured.

The driving force of the engine 1 for rotating the differential case 21 is distributed from the respective pinion gears to the side gears 37, 39, and via the rear axles 9, 11, the right and left rear wheels 13, 15 are arranged.
Is transmitted to When a driving resistance difference occurs between the rear wheels, the driving force of the engine 1 is differentially distributed to each of the left and right sides by the rotation of each pinion gear.

Each gear of the differential gear mechanism 75 is a helical gear. When the differential case 21 is driven to rotate when the vehicle moves forward, the side gears 37 and 39 are slid by being pressed by the sliding portions 81 between each other due to thrust forces 77 and 79 generated by engagement with the pinion gears. When the differential case 21 is driven to rotate in the reverse direction of the vehicle, the flange portion 43 is moved by the washer 51 by the meshing thrust force 83 of the side gear 37.
The side gear 39 slides on the sliding portion 89 with the main body 31 due to the meshing thrust force 87.
The friction coefficient of the sliding portion 81 is larger than the friction coefficient of the sliding portions 85 and 89.

The left end of the long pinion gear 63 slides on the flange 47 and the right end slides on the thrust washer 71 due to the meshing thrust force. The left end of the short pinion gear slides with the main body 31, and the right end slides with the thrust washer 71. These sliding parts have the same coefficient of friction.
In addition, a rotational friction resistance is obtained between (the support surface) between each pinion gear (outer periphery of the tooth tip) and its storage hole.

The rotation of each pinion gear and the side gears 37 and 39 is braked by the frictional resistance of each pinion gear and the frictional resistance of each sliding portion due to the meshing thrust force, so that the differential rotation of the differential gear mechanism 75 is limited. Since this frictional resistance changes in proportion to the transmission torque of the differential gear mechanism 75, each sliding portion constitutes a torque-sensitive differential limiting means.

A hub 91 is disposed between the flange 43 and the flange 47 on the left side gear 37 side.
It is rotatably supported on the outer periphery of. The hub 91 is provided with a connecting portion 95 that penetrates rightward through a gap 93 between the left side gear 37 and the hub 41, and the connecting portion 95 is spline-connected to the right hub 53. Flange 43
A working chamber 97 is formed between the cylindrical member 45, the flange 47, and the hub 91. The working chamber 97 is filled with high-viscosity silicone oil through an injection hole 99 and sealed by a ball 101 caulked into the injection hole 99. Have been. Cylindrical member 45
, A number of outer plates are engaged, and the hub 91 is engaged with inner plates alternately arranged with the outer plates. An X ring 103 (seal having an X-shaped cross section) and a backup ring 105 are arranged between the hub 91 and the hub 41, and an X ring 107 and a backup ring 109 are provided between the side gear 37 and the connecting portion 95. Are arranged to prevent leakage of silicone oil.

Thus, the viscous coupling 111
(Speed-sensitive differential limiting means). Since the outer plate is connected to the left rear axle 9 via the hub 41 and the inner plate is connected to the right rear axle 11 via the hub 91 and the hub 53, the viscous coupling 111 is an SS type. The arrangement limits the differential rotation of the differential gear mechanism 75.

Since the hub 91 of the viscous coupling 111 is connected to the hub 53 by the connecting portion 95, FIG.
Unlike the prior art example, the right axle 237 had to be longer than the left axle 233 in order to connect with the viscous coupling 211.
Can be of equal length.

Thus, the rear differential 7 is formed.

Next, the differential limiting characteristics of the rear differential 7 will be described with reference to FIGS.

FIG. 2 is a graph showing the transfer ratio (R _t ) of the rear differential 7, in which the first quadrant is an area on the forward side and the third quadrant is an area on the reverse side (coasting side). The upper side of the 45 ° straight line 113 in the first and third quadrants is an area of the axial torque transmitted to the right rear wheel 15 via the rear differential 7 when the left rear wheel 13 idles, and the lower side is the right rear wheel 15. Is a region of the shaft torque sent to the left rear wheel 13 when the vehicle idles.

Graphs 115, 117, 119 and 121 are transfer ratios of torque-sensitive differential limiting means, and graphs 123, 125, 127 and 12 are obtained by adding the differential limiting force of the viscous coupling 111 to these graphs.
9 is the differential limiting characteristic of the entire rear differential 7.

The frictional resistance between the pinion gear of the torque-sensitive type differential limiting means and the storage hole is equal to when the left side gear 37 is rotated forward and when the right side gear 39 is rotated forward, and each pinion gear is driven by the meshing thrust force. The sliding frictional resistance of the end portions is made equal left and right as described above.
Therefore, this differential limiting means has no one-sided effect in forward and backward movements, and the graphs 115 and 117 and the graphs 119 and 121 are symmetrical with respect to the straight line 113, respectively. Further, as described above, R _t is greater than R _t during backward sliding portion graphs 115 and 117 because than the sliding resistance is made larger at the time of advance of 85 and 89 the sliding resistance of the sliding portion 81 . In addition, since the viscous coupling 111 is arranged in the SS type, the differential limiting force can be reduced by the respective graphs 115 and 1.
Graphs 123, 125, added to 17, 119, 121
127 and 129 are also symmetrical with respect to the straight line 113, and the rear differential 7 does not produce a one-sided effect.

In the vehicle shown in FIG. 4, for example, even when the left rear wheel 13 idles and the left shaft torque drops to T _L1 when traveling on a rough road, a large T _R1 shaft torque is sent to the right rear wheel 15 to cause a bad condition. Road running performance is greatly improved. At this time, since there is no one-sided effect, the driving force sent to the rear wheels on the contact side on the left and right sides on the idling side is equal, and the maneuverability and safety are greatly improved.
The ability to obtain such a large differential limiting force particularly enhances the stability of the vehicle body under a large torque, and is suitable for sporty running.

Further, as shown in FIG.
The gradient of 5,127,129 is shown in graphs 115,117,1.
It is determined by the gradient of 19,121. Therefore, the effect of the differential limiting force of the viscous coupling 111 is also shown in the graph 11.
The difference between this effect is determined by the gradient of 5, 117, 119, and 121. The difference between this effect and the initial torque T _iD during forward movement, which is a tangent between the graph 123 and the ordinate, and the reverse torque, which is a tangent between the graph 129 and the ordinate. appearing as a difference between the initial torque T _ics.
Here, the gradients of the graphs 123 and 129 are represented by R _tD ,
_Assuming that R _tc and the single torque of the viscous coupling 111 are T _Vc , T _iD = T _Vc (R _tD +1) T _ic = T _Vc (R _tc +1), and since R _tD > R _tc , T T _iD > _Tic .

[0038] Thus, by combining a torque sensitive type differential limiting means with different R _t in forward and reverse, it can be varied in reverse before characteristics of the entire plus characteristics of the viscous coupling 111.

FIG. 3 is a graph showing the differential limiting force with respect to the input torque of the rear differential 7. Graph 131 is improved by the differential limiting force in forward is larger R _t of the graph 123, 125 in FIG. 2, the graph 133 is a graph of the differential limiting force during reverse or when engine braking is 2 127,12
Indicates that it is reduced by 9 R _t is small. Further, broken line 135 represents the limit torque of the ABS (anti-lock brake system), the differential limiting torque T ₂ of the time T ₁ Tosureba its maximum input torque at the time of engine braking without exceeding the limit torque of ABS , ABS
Interference with the system is avoided.

As described above, the rear differential 7 has the SS type viscous coupling 111, which is a speed-sensitive type, in addition to the torque-sensitive type differential limiting means having equal transfer ratios on the left and right sides. In addition, the left-right differential limiting characteristic greatly improves the vehicle's controllability.
In addition, by adopting this structure, it is easy to make the transfer ratio of the torque-sensitive differential limiting means large when the vehicle is moving forward and small when the vehicle is moving backward, so that the differential limiting force of the viscous coupling 111 acts symmetrically. However, a large differential limiting force can be obtained when the vehicle is moving forward, and interference with the ABS of the vehicle can be prevented during engine braking. or,
In addition, the rear axles 9, 11 can be made equal.

Next, a second embodiment will be described with reference to FIG. This embodiment is equivalent to the rear differential 7 of the first embodiment in which the meshing portion between the pinion gears is on the right end side of the differential gear mechanism 75, but this meshing portion is on the left end side of the differential gear mechanism. I do. Hereinafter, only differences from the rear differential 7 will be described. In FIG. 5, members having the same functions as those in FIG. 1 are denoted by the same reference numerals as those in FIG. The differential device of this embodiment is similar to the rear differential 7 of the first embodiment shown in FIG.
As a rear differential 137 of the vehicle.

In the differential case 21, left and right side gears 1 are provided.
39, 141 (differential gears) are arranged, the left side gear 139 is formed on the left hub 143, and the right side gear 141 is formed on the right hub 145. Each of the hubs 143 and 145 supports a free end of each other by a shaft support 147, and a washer 149 is disposed between the right hub 145 and the main body 31. The hub 41 has a left rear axle 9
The right rear axle 11 is spline-connected to the hub 145.

The housing hole 15 provided in the body 31 in the axial direction
A long pinion gear 153 (connecting gear) is slidably and rotatably accommodated in 1, and a short pinion gear (connecting gear) is slidably rotatable in an axial storage hole provided adjacent to the storage hole 151 in the circumferential direction. It is stored in.

The long pinion gear 153 is connected to the left and right gear portions 1.
55, 157 and a shaft 159 connecting them,
The left gear 155 meshes with the left end of the short pinion gear, and the right gear 157 meshes with the right side gear 141. The right end of the short pinion gear meshes with the left side gear 139. Each of these gears is a helical gear. Thus, the differential gear mechanism 161 is configured.

When the differential case 21 is driven to rotate in the rotation direction when the vehicle is moving forward, the side gears 139 and 141 slide on the sliding portions 163 of each other due to the thrust force meshing with the pinion gears. When the differential case 21 is driven to rotate in the reverse direction, the flange portion 43 slides on the sliding portion 165 with the washer 51 due to the meshing thrust force in the opposite direction, and the hub 145 slides on the sliding portion 167 with the washer 149. Sliding with The coefficient of friction of the sliding part 163 is
7, so that the frictional resistance when moving forward is larger than when moving backward. The left end of each pinion gear slides with the hub 143 due to the thrust force of the meshing portion, and the right end of the
1 and the thrust washer 71. The friction coefficients of these sliding portions are made equal. Each sliding portion constitutes a torque-sensitive differential limiting means for the differential gear mechanism 161. The viscous coupling 111 is connected to the hub 4
1 and the hub 145 are arranged in an SS type.

Accordingly, the rear differential 137 has no one-sided effect of the differential limiting force in forward and backward traveling, and a large differential limiting force is obtained in forward traveling, and the differential limiting force is reduced in reverse traveling (coasting). It can provide the vehicle with excellent maneuverability and sporty driving performance,
Interference with S can be avoided.

The third embodiment will be described with reference to FIG.

In this embodiment, a plunger pump type coupling 169 is arranged in the rear differential 7 of the first embodiment with respect to a viscous coupling 111 as a speed sensitive type differential limiting means. The coupling 169 and the differential gear mechanism 171 for constituting the torque-sensitive differential limiting means are provided with the left and right rear axles 9,
11 between the left and right hubs 173 and 175
It is arranged in the mold. This embodiment also has the same effects as the first and second embodiments.

[0049]

The differential device according to the present invention has a differential limiting characteristic between when the power transmission shaft on one side of the differential gear mechanism runs idle and when the other power transmission shaft on the differential gear side runs idle. Since the speed-sensitive differential limiting means is disposed between the power transmission shafts in addition to the torque-sensitive differential limiting means having uniform torque, uniform differential limiting characteristics can be obtained between one side and the other side. Also, the differential limiting force of the torque-sensitive differential limiting means can be easily changed in the direction of the differential rotation.

[Brief description of the drawings]

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

FIG. 2 is a graph showing a differential limiting characteristic of the first embodiment.

FIG. 3 is a graph showing a differential limiting characteristic of the first embodiment.

FIG. 4 is a skeleton configuration diagram showing a power system of a vehicle using each embodiment.

FIG. 5 is a sectional view of a second embodiment.

FIG. 6 is a sectional view of a third embodiment.

FIG. 7 is a sectional view of a first conventional example.

FIG. 8 is a sectional view of a second conventional example.

FIG. 9 is a graph showing a differential limiting characteristic of the first conventional example.

FIG. 10 is a graph showing a differential limiting characteristic of the second conventional example.

[Description of Signs] 7,137 Rear differential (differential device) 9 Left rear axle (power transmission shaft) 11 Right rear axle (power transmission shaft) 21 Differential case 37,39,139,141 Side gear (differential gear) 63,153 Pinion gear (Connecting gear) 75, 161, 171 Differential gear mechanism 111 Viscous coupling (speed-sensitive differential limiting means) 169 Plunger pump type coupling (speed-sensitive differential limiting means)

Claims (1)

(57) [Claims] 1. A pair of differential gears connected to respective power transmission shafts, meshing with these differential gears and meshing with each other, and being arranged on a parallel axis with the differential gears, the differential gears are differentially driven. A differential gear mechanism comprising: a connecting gear composed of a pair of pinion gears rotatably connected; and a differential case that rotatably supports each of these gears and slidably and rotatably stores the pair of tooth tips in a storage hole. In the differential gear mechanism, when a drive rotation difference occurs in one or the other power transmission shaft in a state where the differential case is rotationally driven, the differential is limited in response to the frictional resistance between the pinion gear and the differential case, and the other one or the other is limited. Torque-sensitive differential limiting means having equal driving forces sent to one power transmission shaft, a cylindrical member connected to one differential gear of the pair of differential gears, and the other differential gear Speed-sensitive differential limiting means for limiting the differential in response to a differential rotation speed with a hub connected to the hub, and at least one of a pair of pinion gears.
One end of the non-ion gear is axially attached to one side of the differential case.
Is positioned and the other end is in axial contact with the other side of the differential case.
A differential device characterized in that it is positioned in the axial direction via the contacting cylindrical member .