JP2003232432A - Differential gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential lock function while improving package performance using an electromagnet. <P>SOLUTION: This differential gear is provided with a differential mechanism 5 to distribute driving force of an engine from a differential case 3 through side gears 31 and 33 to the wheel side, a friction clutch 13 provided between a differential case 5 and an armature 7, the electromagnet 15 to move and operate the armature 7 to connect the clutch 13, and a cam means 9 provided between the armature 7 and the side gear 33 to tighten the clutch 13 through the armature 7. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential limiting function,
Alternatively, the present invention relates to a differential device having a differential lock function. 2. Description of the Related Art Japanese Patent Publication No. 50-20331 discloses a differential limited differential 201 as shown in FIG. The differential limiting type differential device 201 includes a differential case 203 that rotates by the driving force of an engine, a bevel gear type differential mechanism 205 that distributes the rotation of the differential case 203 to the wheels, and a differential rotation of the differential mechanism 205. , A cam mechanism 209 for operating the cone clutch 207, a return spring 211, an actuator 213, a stop mechanism, and the like. The cone clutch 207 has a wedge member 215
The cam mechanism 209 is provided between the left side gear 217 of the differential mechanism 205 and the wedge member 215. Also, the return spring 211 urges the wedge member 215 to the right in the figure to release the connection of the cone clutch 207,
The cam mechanism 209 is kept in the meshing state. The actuator 213 includes a pin 219, a weight 221, and another weight that forms a pair with the weight 221. A gear portion 223 formed on the pin 219 meshes with a gear portion 225 formed on the wedge member 215. ing. [0006] Both ends of the coil spring 227 are pressed against the pin 219 by the urging force. Each weight is connected to the pin 219 via the coil spring 227, rotates together with the pin 219, and swings outward. It is configured as follows. Each weight is urged inward in the swing direction by another coil spring, and swings outward at an angle corresponding to the magnitude of the centrifugal force accompanying rotation. The stop mechanism includes a tab member, a weight attached to the tab member, a coil spring, and the like. The tab member is rotatably attached to the differential case 203, and the tab member has a stop tab portion. When each of the above weights swings outward, it locks with this stop tab portion. In addition, the weight increases the number of rotations at which the stop tab portion is locked to each weight by displacing the tab member radially outward by centrifugal force, and the coil spring opposes the centrifugal force of the weight to prevent the tab member from rotating. Is urged radially inward to reduce the number of rotations at which the stop tab portion and each weight are locked. When one of the wheels idles on a rough road or the like, the differential mechanism 205 generates a differential rotation, and the side gear 217 and the differential case 203 rotate differentially, and the wedge member connected to the side gear 217 by the cam mechanism 209. The wedge member 215 rotates through the gear portions 223 and 225.
The pin 219 meshing with the coil spring 22 rotates, and the coil spring 22
Each weight connected to the pin 219 via 7 swings outward by centrifugal force. If the swing angle (differential rotation speed) of each weight is larger than the set value, each weight is connected to a tab member (stop mechanism).
And the rotation of the wedge member 215 is braked via the tab member, the weight, the coil spring 227, the pin 219, and the gear portions 223, 225, and the wedge member 215 is stopped.
A difference in rotation is generated between the side gear 217 and the side gear 217. The differential torque causes the cam mechanism 209 to operate, and the generated cam thrust force moves the wedge member 215 to the left against the return spring 211, causing the cone clutch 207 to move. To conclude. When the cone clutch 207 is engaged, the wedge member 215 is connected to the differential case 203 via the cone clutch 207, so that the differential torque applied to the cam mechanism 209 is strengthened, and the cam thrust force is further increased. The differential of the moving mechanism 205 is locked. When the differential rotation speed decreases, the swing angle of each weight becomes smaller, the lock between the weight and the stop tab is released, and the braking of the wedge member 215 by the stop mechanism is stopped. The wedge member 215 returns to the right, the engagement of the cone clutch 207 is released, and the differential lock of the differential mechanism 205 is released. The stop mechanism adjusts the position of the tab member (stop tab portion) by the weight and the coil spring, and adjusts the differential rotation speed at which each weight is locked (the cone clutch 207 is engaged). I do. [0014] However, in the differential limiting type differential device 201, the differential limiting function such as the actuator 213 and the stop mechanism is mechanically configured.
If the wheels do not spin at high speed, differential locking will not occur. Therefore, the differential can be arbitrarily locked according to changes in speed, steering, road surface conditions, etc., while the vehicle is running.
Adjustments such as unlocking cannot be made. The actuator 213 and the stop mechanism have a very large number of components, and it is difficult to adjust the weight (centrifugal force) of each weight and weight and the spring constant of the three types of coil springs used. In addition, the operation tends to be unstable, and the variation among products is likely to increase. In order to lock and release the differential according to the speed, steering, road surface conditions, etc. of the vehicle, a clutch for limiting the differential is provided by a hydraulic actuator using air pressure or hydraulic pressure or an actuator using an electromagnet. Requires a differential limiting mechanism configured to operate
Since a large differential limiting force is required to lock the differential, a hydraulic actuator is used for such a differential limiting mechanism. However, a differential limiting mechanism using a fluid pressure actuator requires a pressure source (pump) and has a wide arrangement space including a pump, a pressure line (piping), and a layout space thereof. You need
In order to prepare this space, it is necessary to change a casing or a vehicle body for accommodating the differential device, and it is difficult to unitize (package: modularize) the pump, the pressure line, and the like with the differential device. Further, in the fluid pressure type actuator, it is easy to cause a decrease in function and a decrease in reliability due to a pressure leak in each part, and in addition, consideration is given to strengthening a seal in each part of the pressure line in order to prevent the pressure leak. Is necessary, and an increase in cost accompanying this is inevitable. On the other hand, if an electromagnet is used for the actuator, a pump and a pressure line are not required, and a space for arranging the pump and the pressure line is not required, so that the structure is simple and compact. Since there is no work, assembly is easy and assembly cost is reduced. In addition, the uniting of the differential device and the electromagnet is possible and the package is high, so that the casing and the vehicle body of the differential device need not be changed or remodeled, or they can be reduced. In addition, a high reliability can be obtained by being released from a decrease in function due to a pressure leak such as a fluid pressure type actuator. In addition, it is not necessary to take measures such as strengthening a seal of a pressure line. The accompanying increase in costs is avoided. However, in the case of an actuator using an electromagnet, it is difficult to obtain a sufficient differential limiting force for locking the differential. Accordingly, an object of the present invention is to provide a differential device which can obtain a differential lock function while using an electromagnet, and can be changed and modified on a casing or a vehicle body side by making it into a unit, thereby making it unnecessary. . According to a first aspect of the present invention, there is provided a differential device that rotates by receiving a driving force of a motor, and a differential that distributes rotation of the differential case from a pair of output side gears to wheels. A mechanism, a friction clutch provided between the differential case and the armature, an electromagnet for moving the armature to fasten the friction clutch, and an armature provided between the armature and a side gear, and the armature is provided by a cam thrust force. And a biasing member for biasing the armature toward the cam means side. When the armature is moved by the electromagnet, the friction clutch is engaged and the armature is connected to the differential case side. In this state, when differential rotation occurs in the differential mechanism, the differential torque is transmitted to the cam between the armature and the side gear. The friction clutch is tightened by the generated cam thrust force, and the differential is locked by the generated large differential limiting force. As described above, in the differential apparatus of the present invention, the friction clutch for limiting the differential is provided between the differential case and the armature, and the cam means is provided between the armature and the side gear to retighten the friction clutch. Therefore, a sufficient differential limiting force for locking the differential can be obtained even with an actuator using an electromagnet. As described above, in the present invention, the friction clutch doubles as the pilot clutch and the differential limiting clutch. Also, by controlling the excitation of the electromagnet, the excitation current, the excitation stop, etc., the differential can be arbitrarily limited according to changes in speed, steering, road surface condition, etc. during the running of the vehicle, and the differential is locked. The lock can be released. Further, unlike the configuration using the fluid pressure type actuator, the pump and the pressure line and the space for arranging them are not required, so that the structure is simple and compact, the on-board property is improved, and the pressure line routing work is performed. Because there is no assembly, assembly is easy, and assembly cost is reduced. Furthermore, the uniting of the differential device and the electromagnet is possible and the package is high, so that there is no need to change or modify the casing for housing the differential device or the vehicle body side, or it is not necessary. In addition, the function does not deteriorate due to pressure leakage as in the fluid pressure type actuator, and high reliability can be obtained. In addition, consideration such as strengthening the seal of the pressure line becomes unnecessary. The cost increase associated with is avoided. DESCRIPTION OF THE PREFERRED EMBODIMENTS A differential device 1 (one embodiment of the present invention) will be described with reference to FIG. Hereinafter, the left and right directions are the left and right directions in FIG. 1, and members and the like without reference numerals are not shown. As shown in FIG. 1, the differential device 1
Are a differential case 3, a bevel gear type differential mechanism 5, an armature 7, a cam 9 (cam means), and a return spring 11.
(Biasing member), a multi-plate pilot clutch 13 (friction clutch), an electromagnet 15, a controller, and the like. The differential case 3 comprises a cover 17, a casing body 19 made of a non-magnetic material, and a rotor 21 made of a magnetic material. The cover 17 is fixed to the left opening of the casing body 19 with bolts. It is welded to the right opening. The differential case 3 is arranged inside the differential carrier, and the boss portion 23 of the cover 17 and the boss portion 25 of the rotor 21 are respectively supported by the differential carrier via bearings. An oil reservoir is formed inside the differential carrier. A ring gear is fixed to the differential case 3 with bolts, and this ring gear meshes with an output-side bevel gear of a power transmission system. The power transmission system is connected to the transmission, and the differential case 3 is driven to rotate by the driving force of an engine (motor) transmitted through the transmission and the power transmission system. The differential mechanism 5 includes a pinion shaft 27, a pinion gear 29 supported on the pinion shaft 27,
The output side gears 31 and 33 are provided. Each pinion shaft 27 has an end engaged with a through hole 35 provided in the casing body 19 and is fixed by a spring pin.
Are respectively engaged with the pinion gear 29 from the left and right. Between the casing body 19 and the pinion gear 29, the centrifugal force of the pinion gear 29 and the side gear 3
Pinion gear 29 generated by engagement with gears 1 and 33
A spherical washer 37 receiving the meshing reaction force is disposed. The hub 39 of the left side gear 31 has a cover 1
The hub 39 is connected to the left wheel side via a spline-connected axle. The hub 43 of the right side gear 33 is connected to the right wheel via a spline-connected axle. A thrust washer 45 is disposed between the side gear 33 and the rotor 21 to receive a reaction force from the engagement of the side gear 33. The driving force of the engine for rotating the differential case 3 is distributed to the left and right side gears 31 and 33 via the pinion shaft 27 and the pinion gear 29, and transmitted to the left and right wheels via the axle. When a difference in driving resistance occurs between the left and right wheels, for example, when traveling on a rough road, the driving force of the engine is differentially distributed to the left and right sides by the rotation of each pinion gear 29. The armature 7 is a hub part 4 formed integrally.
The right side gear 33 is supported on the outer periphery of the hub 43 by a hub 47. The cam 9 is provided between the flange 49 of the armature 7 and the side gear 33, and the return spring 11 urges the armature 7 in the direction in which the cam 9 engages (leftward). The pilot clutch 13 is provided between the casing body 19 and the armature 7. The outer plate 51 is connected to a spline portion 53 formed on the inner periphery of the casing body 19, and the inner plate 5
Reference numeral 5 is connected to a spline portion 57 formed on the outer periphery of the hub portion 47 (armature 7). The core 59 of the electromagnet 15 is arranged with an appropriate air gap between the core and the rotor 21, and is supported on the rotor 21 by bearings and is centered. The core 59 is connected to the differential carrier via a support member and is prevented from rotating. The lead wire of the electromagnet 15 is drawn out of the differential carrier through the grommet and connected to a vehicle-mounted battery. The core 59, the rotor 21, the pilot clutch 13 and the armature 7 constitute a magnetic path of the electromagnet 15. The rotor 21 is divided into a radially outer side and an inner side by a stainless steel ring 61 which is a nonmagnetic material. In addition, each plate 5 of the pilot clutch 13
At the radial position corresponding to the ring 61, the notches 1 and 55 are provided with a plurality of notches 63 and a bridge portion connecting the notches 63 in the circumferential direction. The ring 61 and the notch 63 prevent the magnetic flux from being short-circuited on the magnetic path. The controller detects the turning traveling from the vehicle speed, the steering angle, the lateral G, etc., or performs the excitation of the electromagnet 15, the control of the excitation current, the stop of the excitation, and the like according to the road surface condition. When the electromagnet 15 is excited, a magnetic flux loop is formed in the above-described magnetic path, the armature 7 is attracted, and the pilot clutch 13 is pressed and engaged with the rotor 21 to generate pilot torque. With the pilot torque generated,
When differential rotation occurs in the differential mechanism 5, the armature 7 connected to the differential case 3 via the pilot clutch 13
And the armature 7 connected to the side gear 33 by the cam 9, a differential torque is applied to the cam 9, and the armature 7 moves rightward by receiving the generated cam thrust force to tighten the pilot clutch 13 further. A large differential limiting force is obtained by the self-locking function of the pilot clutch 13 by the cam 9. If the differential limiting force exceeds the differential locking torque of the differential mechanism 5, the differential is locked. . Further, in a range where the differential limiting force is smaller than the differential lock torque, a torque-sensitive differential limiting force can be obtained by the cam thrust force of the cam 9 which increases and decreases according to the change in the differential torque. Further, if the exciting current of the electromagnet 15 is controlled to adjust the slip of the pilot clutch 13, the pilot torque of the pilot clutch 13 and the cam thrust force of the cam 9 change, so that the differential limiting force is freely controlled. be able to. When the excitation of the electromagnet 15 is stopped, the armature 7 returns to the left by the urging force of the return spring 11, the pilot clutch 13 is released, the pilot torque and the cam thrust force of the cam 9 disappear, and the differential mechanism 5, the differential rotation becomes free. The return spring 11 and the washer 45 maintain an appropriate gap between the armature 7 and the pilot clutch 13, so that the pilot clutch 13 is inadvertently moved via the armature 7 by the engagement reaction force of the side gear 33. It is fastened to prevent a differential limiting force from being generated. The controller excites the electromagnet 15, controls the excitation current, and stops the excitation at an arbitrary timing, and performs differential locking, differential limiting force adjustment, and the like according to changes in vehicle speed, steering conditions, road surface conditions, and the like. Unlocking and the like are performed, and by such an operation, the startability, acceleration, turning performance, maneuverability, stability, running ability on a rough road, and the like of the vehicle can be significantly improved. The differential case 3 is provided with an opening.
Further, spiral oil grooves are formed on the inner circumferences of the boss portions 23 and 25. The lower half of the differential device 1 is immersed in oil in an oil sump. With rotation, the oil flows out of the opening and the spiral oil groove into and out of the differential case 3, and the gears 29, 31, 33 , A sliding portion between the outer periphery of the pinion shaft 27 and the pinion gear 29, a thrust washer 45, a spherical washer 37, and a side gear 31.
, A sliding portion between the armature 7 (hub 43) and the side gear 33, the cam 9, the pilot clutch 13,
Both ends of the return spring 11 are sufficiently lubricated and cooled. The performance (magnetic force) of the electromagnet 15 is stabilized by the oil that the differential case 3 (ring gear) rotates and splashes.
Operation function of 3 is stabilized. Thus, the differential device 1 is configured. The differential device 1 includes a differential case 3
By providing the pilot clutch 13 between the armature 7 and the armature 7 and providing the cam 9 between the armature 7 and the side gear 33, a self-locking function for retightening the pilot clutch 13 is obtained. However, a large differential limiting force that can lock the differential can be obtained. Further, by performing operations such as excitation of the electromagnet 15, control of the excitation current, and stop of excitation, differential locking, differential limiting force adjustment,
The lock can be released, and the startability, acceleration, turning, maneuverability, stability, running ability on a rough road, and the like of the vehicle can be greatly improved. Further, the use of the electromagnet 15 eliminates the need for a pump or pressure line such as a fluid pressure type actuator and a space for arranging them, thereby making the structure simple and compact and improving the mountability. Further, since there is no work of drawing the pressure line, the assembling is easy and the assembling cost is reduced. Further, since the electromagnet 15 can be easily unitized with the differential device 1, the differential device 1 has a high packaging property, and no change or remodeling of the differential carrier and the vehicle body is required or required. Further, the function does not deteriorate due to pressure leakage as in a fluid pressure type actuator, and high reliability can be obtained. In addition, it is not necessary to take measures such as strengthening the seal of the pressure line. The cost increase associated with is avoided. The friction clutch used in the differential device of the present invention is not limited to a multi-plate clutch, but may be another type of friction clutch such as a cone clutch. In the present invention, the differential mechanism is not limited to a bevel gear type differential mechanism. For example, a planetary gear type differential mechanism and a pinion gear slidably housed in a housing hole of a differential case may be used. Or a differential mechanism using a worm gear. Further, the differential device of the present invention
Front differential (differential device that distributes engine driving power to left and right front wheels), rear differential (differential device that distributes engine driving force to left and right rear wheels), and center differential (the engine driving force is distributed to front and rear wheels) Differential device). According to the differential device of the present invention, a friction clutch for limiting the differential is provided between the differential case and the armature and a cam means is provided between the armature and the side gear to increase the friction clutch. A self-locking function for tightening is obtained, and a sufficient differential limiting force for locking the differential is obtained even with an actuator using an electromagnet. Further, the differential limiting force is arbitrarily adjusted according to changes in speed, steering conditions, road surface conditions, etc., to improve startability, acceleration, turning, maneuverability, stability, running on rough roads, and the like. It can be greatly improved. Further, a pump, a pressure line, and a space for disposing the pump and the pressure line are not required. Further, the packaging property is high, and it is not necessary or necessary to change or modify the casing of the differential device or the vehicle body.

[Brief description of the drawings] FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is a sectional view of a conventional example. [Explanation of symbols] 1 Differential device 3 differential case 5 Differential mechanism 7 Armature 9 cam (cam means) 11 Return spring (biasing member) 13 Pilot clutch (friction clutch) 15 Electromagnet 33 Side Gear

Claims (1)

Claims: 1. A differential case that rotates by receiving a driving force of a prime mover, a differential mechanism that distributes rotation of the differential case from a pair of output side gears to wheels, and a differential case and an armature. A friction clutch provided therebetween; an electromagnet for moving the armature to fasten the friction clutch; and an electromagnet provided between the armature and a side gear to press the friction clutch via the armature by a cam thrust force. A differential device comprising: a cam means; and an urging member for urging the armature toward the cam means.