JP2552364B2 - Controlled differential rotation sensitive joint - Google Patents

Description

The present invention relates to a driving force distribution device for a multi-wheel drive vehicle such as a four-wheel drive vehicle, a differential device for front and rear wheels and a left and right wheel, and a front and rear wheel and a left and right wheel. The present invention relates to an improvement in a control type rotation difference sensitive joint used as a differential limiting device or the like.

(Prior Art) Japanese Patent Application Laid-Open No. 63-10
Joints such as those described in the 1567 publication are known.

According to this conventional source, a fluid is discharged in accordance with a relative rotational speed difference between a first rotating shaft and a second rotating shaft that are coaxially rotatable relative to each other, and the first and second rotating shafts. An actuator provided in the rotation part (rotor) to which the rotation shaft is connected, and a rotation difference sensitive joint that converts the amount into fluid pressure by restricting outflow by an orifice and further converts this fluid pressure into transmission torque between both shafts. Indicates an axially stroked spool, which is adapted to change the orifice opening area.

(Problems to be Solved by the Invention) However, in such a conventional control type rotational differential sensing joint, since the spool and the actuator are provided in the rotor that is the rotating portion, there are problems as listed below. there were.

Since the actuator rotates at high speed together with the rotor, the durability of the actuator deteriorates.

Since it is necessary to use a slip ring for applying electricity to the actuator, the actuator becomes inoperative due to wear of the slip ring or poor contact.

When a rotary shaft such as an axle is arranged in a penetrating state on the rotary shaft, the actuator cannot be attached to the rotary shaft.

When the opening area of the orifice that opens on the inner surface of the spool chamber is changed and controlled by the stroke position of the spool, torque fluctuations will result unless the orifices are finished uniformly and with high accuracy. Has a high valve sensitivity and is accompanied by valve vibration when the orifice is fully closed.

The present invention has been made in view of the above-mentioned problems, and in a control type rotational differential sensing joint in which an opening area of an orifice can be changed by an external actuator, a rotating shaft such as a wheel penetrates a rotating shaft center. It can be applied when it is placed, and it improves the durability and operational reliability of the actuator, and secures the smooth and highly accurate opening area change control near the opening and closing of the opening area without requiring high orifice processing accuracy. The task is to do.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the control type rotationally differential sensing joint of the present invention, a first rotating shaft and a second rotating shaft are coaxially and relatively rotatably arranged. The flow rate discharged according to the relative rotational speed difference between the shaft and the first and second rotary shafts is converted into fluid pressure by the outflow regulation by the orifice, and this fluid pressure is converted into transmission torque between both shafts. Rotation sensitive joint, an actuator that is provided in the non-rotating portion, and that performs a rotating operation about a position deviated from the central axis of the first and second rotating shafts, and is rotated by the actuator. A rotating member, a bearing, a slide mechanism that is provided around the first or second rotating shaft and is movable in the axial direction when the rotating member rotates, and a plurality of orifices are opened. Rotate with the spool chamber and slide Slidably provided with axial direction movement of the structure, the end portion outer peripheral, characterized in that it comprises a a spool axial grooves are formed at positions corresponding to the plurality of orifices.

(Operation) When a relative rotational speed difference is generated between the first rotary shaft and the second rotary shaft, the flow rate discharged according to the relative rotary speed difference is converted into fluid pressure by the outflow regulation by the orifice. Further, this fluid pressure is converted into a transmission torque between both shafts.

When changing the transmission torque characteristic, when the actuator provided in the non-rotating part is rotated by a predetermined control command, the rotating member is centered at a position deviated from the central axes of the first and second rotating shafts. As a result, the rotational movement is converted into axial movement by a slide mechanism having a bearing, and the spool slides in the axial direction as the slide mechanism moves. This sliding of the spool changes the relative position with respect to the spool chamber in which the plurality of orifices are opened, and the orifice opening area is changed depending on the positional relationship between the orifice and the spool.

When changing the orifice opening area,
An actuator that is provided in the non-rotating portion and that performs a rotating operation about a position deviated from the central axes of the first and second rotating shafts; and a rotating member that is rotated by the actuator.
A slide mechanism having a bearing and provided around the first or second rotation shaft and movable in the axial direction in accordance with the rotation of the rotation member causes the control spool to slide in the axial direction. Therefore, even if a rotating shaft such as an axle is arranged in a penetrating state at the center of the rotating shaft, it does not hinder the installation of the actuator.

Since the actuator is provided in the non-rotating portion, the durability is improved and the operation reliability is improved as compared with the case where the actuator is provided in the rotating portion and the drive electricity is applied through the slip ring.

Further, since the slide mechanism has a bearing, the frictional resistance due to the relative rotation between the stationary side (rotating member side) and the rotating side (rotating shaft side) of the sliding mechanism is kept low, and the durability is deteriorated due to wear. To be prevented.

Further, since the axial groove is formed at the position corresponding to the plurality of orifices on the outer circumference of the end portion of the spool, the opening area is formed by only the axial groove in the vicinity of the closed opening of the orifice opening area. For this reason, the valve sensitivity near the point where the orifice opening area is completely closed becomes dull, torque fluctuations are suppressed small, and valve vibration due to a large hydraulic pressure drop when the orifice is fully closed is also suppressed. Further, in the vicinity of the closed opening of the orifice opening area, the amount of change in the orifice opening area with respect to the amount of change in the spool stroke becomes small, so that highly accurate opening area change control can be secured in the closed area.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

 First, the configuration will be described.

FIG. 9 is a schematic diagram showing a power train and a limited slip differential control system of a rear-wheel drive vehicle to which the control type rotational differential sensing joint A of the embodiment is applied. , R
It is applied as a differential limiting control device for the differential device provided between W.

In FIG. 9, reference numeral 180 is a motor actuator for changing the differential limiting torque characteristic of the control type rotationally sensitive joint A.
The motor actuator 180 is drive-controlled by the controller 200. And in this controller 200,
A vehicle speed sensor 201, a right rear wheel rotation sensor 202, a left rear wheel rotation sensor 203, a steering angle sensor 204, a throttle opening sensor 205, and a brake switch 206 are connected.

FIG. 1 is a cross-sectional view showing a rear differential in which a control type rotational difference sensitive joint A is incorporated in a differential gear 1, and the differential gear 1 has a driving force via a drive pinion 3 and a ring gear 4. Is input to the differential case 10, a pinion 12 rotatably supported via a pinion shaft 11, a pair of side gears 13 and 14 meshing with the pinion 12, and two side gears 13 and 14 connected to each other. It has a left drive shaft 15 and a right drive shaft 16.

When the differential rotation is not generated, the drive torque is transmitted to the left and right drive shafts 15 and 16 in a uniform distribution, and when the differential rotation is generated, the differential torque is controlled by the differential rotation sensitive joint A of the control type. The torque is transmitted from the high rotation side to the low rotation side.

Hereinafter, referring to FIGS. 1 to 6, the control type rotation difference sensitive joint A will be described.
The configuration of will be described.

Among the control type rotational differential joints A, the rotational differential joint 20 showing the rotational differential joint function includes the left drive shaft 15 (first rotary shaft) and the right drive shaft 16 (second rotary shaft). The cam surface 31 formed on the inner surface of the drive housing 30 splined to the one left drive shaft 15, the rotor 40 splined to the other right drive shaft 16, and the rotor 40 provided on the rotor 40,
A radial arrangement of the driving piston 50 that reciprocates in the radial direction while slidingly contacting the cam surface 31 by differential rotation, a cylinder chamber 60 that changes in volume as the driving piston 50 reciprocates, and a balance between the cylinder chamber 60 The spool chamber 72 communicated with the oil passage 70 and the orifice 71, one end of the spool chamber 72 is opened and the regulator oil passage 80 is formed.
Accumulator chamber 90 communicating with the cylinder chamber 60 via
It has and.

32 is a drive housing cover, 41 is a cylinder hole, 42 is a relief valve hole, 51 is a seal ring, 81 is a ball one-way valve, 91 is an accumulator piston,
Reference numeral 92 is a spring retainer, and 93 is a return spring.

Orifice opening area changing means 110 of the orifice 71
Is a motor actuator 180, a slide mechanism 170 (motion conversion mechanism), a cross rod 160 and a push rod 1
It has 50 and a spool 120.

The motor actuator 180 includes a rotation difference sensitive joint 20.
Is mounted on the differential housing 5 (non-rotating portion) close to the fork, and as shown in FIG. 3, it is mounted on the fork shaft 181 and the fork shaft 181, which is attached to the outer periphery of the left drive shaft 15. It has a U-shaped fork 182.

The slide mechanism 170 is a sleeve ring 171 provided on the outer periphery of the left drive shaft 15 so as to be slidable in the left-right direction in FIG.
And a ball bearing 172 on the outer circumference of the sleeve ring 171.
And a bearing retainer 173 provided to allow relative rotation with the fork 182 interposed therebetween. The fork 182 contacts the bearing retainer 173.

The cross rod 160 is arranged in a cross hole 140 having a large hole diameter that allows a stroke amount required for the spool 120 formed through the left drive shaft 15, and one end thereof is fixed to the sleeve ring 171. The rod is an axial radial rod whose end is fixed to the push rod 150.

The push rod 150 is arranged in a center hole 130 formed through the center shaft of the left drive shaft 15, one end of which is fixed to the cross rod 160, and a spherical surface 150a
The other end of the rod is an axial rod provided in pressure contact with the spool 120.

The spool 120, as shown in FIG.
Spool hole 40b formed at the rotational axis position of the orifice part 40a as a separate component that is press-fitted and fixed at the axial center position of
In addition, the oil seal 121 is slidably arranged in an oil-tight state.

In the orifice part 40a, as shown in FIG. 5, an oil passage 70a formed by a round hole communicating with the balance oil passage 70,
Six orifices 71 formed by square holes are radially formed.

As shown in FIG. 6, the spool 120 has axial grooves 120a formed at the positions corresponding to the six orifices on the outer circumference of the end on the accumulator chamber 90 side. It is an inclined groove in which the depth of the groove is gradually changed deeper toward the spool end surface 120b.

Further, an engagement pin 120c is provided on the body of the spool 120 so as to project in the radial direction, and the engagement pin 120c is engaged with an engagement groove 40c formed in the inner surface of the spool hole 40b, whereby the spool 120 is made into an orifice part. Rotate together with 40a (rotor 40),
The positional relationship between the axial groove 120a and the orifice 71 is fixed.

Incidentally, 122 is a stopper ring provided at the end of the engaging groove 40c.

 Next, the operation will be described.

When a difference in rotation speed occurs between the left and right rear wheels RW, RW connected to the left and right drive shafts 15, 16 when driving on a rough road or when one wheel is stacked, relative rotation also occurs between the drive housing 30 and the rotor 40. The relative rotation causes the driving piston 50 slidingly contacting the cam surface 31 to reciprocate in the radial direction, and of this reciprocation, when the volume of the cylinder chamber 60 is reduced by moving toward the center of the rotation axis, the spool 120 regulates the outflow. The pressure in the cylinder chamber 60 rises due to the flow resistance generated by, and the hydraulic pressure obtained by multiplying the generated hydraulic pressure and the pressure receiving area of the piston 50 becomes the force that presses the driving piston 50 against the cam surface 31,
This pressing force acts as the differential limiting torque, and in the distribution of the driving torque, the differential is limited such that the high-speed rotation side is reduced and the low-speed rotation side is increased from the equal torque distribution.

The differential limiting torque characteristic of the device of this embodiment is
It can be arbitrarily changed by changing the opening area of the orifice 71.

That is, when the fork 182 is rotated by the motor actuator 180 in the direction of arrow C in FIG. 3, the bearing retainer 173 slides to the right in FIG.
The slide mechanism 170 moves to the right in the figure, and the cross rod 160 and the push rod 150 move as shown in the lower side of FIG. 1, whereby the spool 120 slides to the right in FIG. The opening area of the orifice 71 is reduced.

The effect of changing the orifice opening area will be described with reference to FIGS. 7 and 8.

FIG. 7a shows a state where the orifice opening area is fully opened. At this time, the hydraulic oil is mainly the orifice 71 and the end surface 1 of the spool 120.
It flows through a large opening formed by 20b and prevents the flow path resistance from increasing even when the viscosity of the hydraulic oil is large at low temperatures.

FIG. 7b shows a state in which the large opening is closed from the fully opened state, and when the spool 120 strokes to this position, a small flow path constituted by the closed cut surface 71a of the orifice 71 and the axial groove 120a of the spool 120 is formed. The hydraulic oil begins to flow and the valve sensitivity becomes dull from this point.

FIG. 7c shows a state near the closed end of the orifice opening area, and in this spool stroke region, the bottom surface of the axial groove 120a is inclined, so that the valve sensitivity becomes further dull compared to the state of FIG. 7b. There is.

FIG. 7d shows a state in which the orifice 71 is completely closed.

And, FIG. 8 is a change characteristic of the orifice opening area with respect to the spool stroke, and the characteristics a, b, c, d of FIG. 8 are shown.
Points are shown corresponding to FIGS. 7a, 7b, 7c, and 7d, respectively.

In this way, as the orifice opening area decreases,
FIG. 10 shows a differential limiting torque characteristic that shifts from the low range side to the high range side in the characteristic of FIG.

Also, from the fully closed state of the orifice to the motor actuator
When 180 is driven in the opposite direction, the fork 182 rotates in the direction opposite to the arrow C, whereby the position regulation of the slide mechanism 170 by the fork 182 disappears, and the hydraulic pressure on the accumulator chamber 90 side causes the bearing retainer 173 and the fork 173 to move. While maintaining the contact state with the 182, the spool 120 slides to the left side in the drawing, the opening area of the orifice 71 increases, and a differential limiting torque characteristic that shifts from the high range side to the low range side can be obtained. .

The driving of the motor actuator 180 is controlled by the controller 200 as follows, for example.

That is, when the initial turning is detected based on the input signals from the sensors 201 to 206, the low range differential limiting torque characteristic is set in order to improve the turning performance. On the other hand, when the latter half of the turn is detected, the differential limiting torque characteristic of the high range is set in order to improve the dash performance.

Also, if you detect when driving on a bad road or when stuck
High range differential limiting torque characteristics.

Also, when it is detected that the rear wheels RW, RW are braking with the road surface μ on the left and right being different from each other, ABS (anti-lock brake system) for left and right wheels independent control is detected.
In the vehicle with, a low range differential limiting torque characteristic is used to prevent wheel lock on the low μ road side and ensure stability, and to secure a braking force on the high μ road side and maintain a small braking distance. .

In this way, by controlling the differential limiting torque according to various traveling states and vehicle states, desired optimum traveling performance can be obtained.

As described above, in the control type rotation difference sensitive joint A of the embodiment, the features listed below can be obtained together.

Since the push rod 150 and the spool 120 are arranged at the axial center position of the left drive shaft 15 and the motor actuator 180 for driving them is provided in the external non-rotating part offset from the left drive shaft 15 in the direction orthogonal to the axis, This can be applied when the left and right drive shafts 15 and 16 are arranged in a penetrating state at the center of rotation as in the example, and the third rotating shaft penetrates in addition to the relatively rotating first and second rotating shafts. It can also be applied when placed in a state.

Since the motor actuator 180 is provided in the differential housing 5 which is a non-rotating portion, the durability of the actuator is improved as compared with an actuator that rotates at a high speed.

Further, since the driving electricity is applied to the motor actuator 180 directly from the wiring, the cause of actuator non-operation due to wear of the slip ring and poor contact is eliminated, and the operational reliability is improved.

Since the axial groove 120a is formed at the position corresponding to the plurality of orifices 71 on the outer periphery of the end of the spool 120, the valve sensitivity becomes dull when the orifice opening area is closed and closed due to only the axial groove 120a. To do.

As a result, even if the orifices 71 are not finished uniformly and with high accuracy, and there are orifices 71 that are completely closed and orifices that are slightly open among the orifices 71, the torque fluctuation is suppressed to a small level. In addition, the valve does not vibrate due to a large hydraulic pressure drop when the orifice is fully closed.

When processing the orifice 71, if only the closed surface 71a is processed with positional accuracy, for example, even if some play exists between the engaging pin 120c and the engaging groove 40c,
Torque fluctuations and valve vibrations near the point where the orifice opening area is completely closed can be almost eliminated, and the orifice opening area change control is not affected.

Spool near the end of the orifice opening area
Since the opening area is formed only by the axial groove 120a of 120, the amount of change in the orifice opening area with respect to the amount of change in the spool stroke is small, and the opening area change control in this closed region can be performed with high control accuracy. can do.

Since the orifice 71 is not directly formed on the rotor 40 but is formed on the orifice part 40a which is a separate part from the rotor 40, the orifice 71 can be formed with high machining accuracy without difficulty in machining the orifice. Can be finished.

The embodiment of the present invention has been described in detail above with reference to the drawings.
The specific configuration is not limited to this embodiment, and even if there are design changes and the like within the scope of the present invention, they are included in the present invention.

For example, in the embodiment, an example in which the control type rotational differential sensing joint of the present invention is applied to the left and right wheel differential limiting device is shown. It may be used as a device or a front and rear wheel differential limiting device.

Further, the orifice 71 is a circle, a rectangle, an ellipse, a triangle, or the like.
It may be formed in any shape.

Further, in the embodiment, the example in which the drive of the motor actuator 180 is automatically controlled by the controller 200 is shown.
The drive may be controlled by manual control by the driver's switch operation, or may be controlled by either automatic or manual control.

Further, in the example, the bottom surface of the axial groove is shown as an inclined surface that promotes the blunting of the valve sensitivity, but how to set the groove width and groove bottom surface shape to obtain desired stable valve sensitivity characteristics. May be.

(Effects of the Invention) As described above, in the control type rotational differential sensing joint of the present invention, the means for controlling the orifice opening area is provided in the non-rotating portion, and the control means for the first and second rotating shafts is provided. An actuator that generates a rotating motion about a position off the central axis, a rotating member that is rotated by the actuator, and a bearing, and are provided around the first or second rotating shaft. A slide mechanism that is movable in the axial direction according to the rotation of the rotating member and a spool chamber in which a plurality of orifices are opened, and is slidable in the axial direction as the slide mechanism moves. Since the means by the spool in which the axial groove is formed at the position corresponding to the plurality of orifices on the outer circumference of the end portion, the effects listed below can be obtained.

(1) When a rotary shaft such as an axle is arranged in a penetrating state at the rotary shaft center, a means for controlling the orifice opening area by an actuator can be applied.

(2) The durability and operational reliability of the actuator are improved.

(3) It is possible to prevent deterioration of durability due to wear of the slide mechanism.

(4) The opening area change control can be ensured smoothly and with high accuracy near the opening area closing cutoff without requiring high orifice processing accuracy.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional plan view showing a rear differential to which a control type rotary differential sensitive joint according to an embodiment of the present invention is applied. FIG. 2 is a vertical sectional front view of the rotary differential sensitive joint taken along the line I-I in FIG. Is a perspective view showing a motor actuator portion of the embodiment joint, FIG. 4 is an enlarged sectional view showing a spool portion of the embodiment joint, FIG. 5 is a sectional view showing an orifice part of the embodiment joint, and FIG. 6 is an embodiment. Perspective view showing spool of fitting, 7a
FIGS. 7b, 7c, and 7d are explanatory views of the action when the orifice opening area is reduced in the embodiment joint, and FIG. 8 is a change characteristic diagram of the orifice opening area with respect to the spool stroke of the embodiment joint, FIG. 9 is a schematic diagram showing an engine drive system and a control system of a vehicle to which the embodiment joint is applied, and FIG. 10 is a differential limiting torque characteristic diagram by the embodiment joint. A: Controlled differential rotation sensitive joint 15: Left drive shaft (first rotary shaft) 16: Right drive shaft (second rotary shaft) 20: Rotational differential joint 71: Orifice 72: Spool Chamber 110 …… Orifice opening area changing means 120 …… Spool 120a …… Axial groove 170 …… Slide mechanism (motion conversion mechanism) 180 …… Motor actuator (actuator)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 63-101567 (JP, A) JP 63-115916 (JP, A) JP 1-135928 (JP, A) JP 1- 135927 (JP, A) JP-A-3-14917 (JP, A) JP-A-3-24329 (JP, A) JP-B-48-29661 (JP, B1) JP-B-16-13896 (JP, Y1)

Claims (1)

(57) [Claims] 1. A first rotary shaft and a second rotary shaft coaxially rotatably arranged relative to each other, and a flow rate discharged according to a relative rotational speed difference between the first rotary shaft and the second rotary shaft. A rotation difference sensitive joint that converts the fluid pressure to a transmission torque between both shafts by restricting outflow by an orifice, and a center of the first and second rotation shafts provided in the non-rotating part An actuator that generates a rotating motion about an off-axis position, a rotating member that is rotated by the actuator, and a bearing, and are provided around the first or second rotating shaft. A slide mechanism that is movable in the axial direction according to the rotation of the rotating member and a spool chamber in which a plurality of orifices are opened is provided so as to be slidable in the axial direction according to the movement of the slide mechanism. Corresponding to the above multiple orifices on the outer circumference Controlled rotation difference sensitive coupling of the spool axial grooves are formed, characterized in that has a to position that.