JPH03213728A - Control-type rotation difference sensitive coupling - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a control type device used as a drive force distribution device of a multi-wheel drive vehicle such as a four-wheel drive vehicle, a differential limiting device between front and rear wheels, left and right wheels, etc. Related to improvement of rotation difference sensitive joints.

(Prior art) As a conventional control type rotation difference sensitive joint, Japanese Patent Application Laid-Open No. 63-1
A joint as described in the publication No. 01567 is known.

This conventional source includes a first rotating shaft and a second rotating shaft that are coaxially arranged so as to be relatively rotatable, and a fluid that is discharged according to the relative rotational speed difference between the first and second rotating shafts. The figure shows a rotation differential sensitive joint that converts the flow rate into fluid pressure by restricting outflow through an orifice, and further converts this fluid pressure into transmission torque between both shafts, and a spool that strokes in the axial direction driven by an actuator. The orifice opening area is changed depending on the relative positional relationship between the driven spool and the orifice.

(Problems to be Solved by the Invention) However, when using such a conventional control type rotation difference sensitive joint to finely control the orifice opening area and optimally control the transmission torque characteristics depending on the driving condition and vehicle condition, If the actuator is simply set, the spool reference position that determines the orifice opening will vary from unit to unit.

That is, the patent application No. 1-156307 proposed earlier by the present applicant
As stated in the specification and drawings of the issue, simply setting the stepping motor, which is the actuator, will not work.
Because the backlash of the motor reduction gear and the play caused by the machining accuracy and assembly accuracy of the forks, sleeves, and bushing rods vary from unit to unit, even if the same rotational angle drive command is output to the stepping motor, the orifice opening may vary in some units. 1 product is S. However, in other units, the orifice opening area varies from unit to unit, such as S, (≠SO).

As a result, there are many units that do not perform optimal control of the transmission torque characteristics according to the intended driving condition and vehicle condition by finely controlling the orifice opening area. In a small-area region, the transmitted torque deviates significantly from the target torque, making it impossible to take advantage of the transmission torque characteristic change control.

Therefore, there is a plan to improve the accuracy of parts processing management and assembly management, and to keep the amount of backlash and play constant for each unit, but in this case, a huge amount of man-hours would be required for processing management and assembly management. , the unit cost would be extremely high.

The present invention has been made with attention to the above-mentioned problems, and is a controlled rotation differential sensitive joint in which the opening area of the orifice can be changed by an external actuator, without increasing the machining accuracy or assembly accuracy of parts. The objective is to eliminate variations in the transmission torque characteristics of individual units while creating a low-cost unit.

(Means for Solving the Problems) In order to solve the above problems, in the controlled rotation difference sensitive joint of the present invention, the spool reference position is determined based on the torque detection value of the shaft member that transmits the rotational drive torque by the actuator. A means for determining position is provided.

That is, a first rotating shaft and a second rotating shaft are coaxially arranged so as to be relatively rotatable; A rotation difference sensitive joint that converts the flow rate discharged according to the relative rotational speed difference of the second rotating shaft into fluid pressure through outflow regulation using an orifice, and further converts this fluid pressure into a transmission torque between the two shafts; an orifice opening area changing means for changing an orifice opening area by stroking a spool with an actuator provided on a non-rotating part; a torque detecting means provided on a shaft member for transmitting rotational driving torque by the actuator; The present invention is characterized by comprising spool reference position determination means for determining that the spool is at the reference position when the torque detection value from the detection means exceeds a predetermined value.

(Function) When a relative rotation speed difference occurs between the first rotation shaft and the second rotation shaft, the flow rate discharged according to the relative rotation speed difference is converted into fluid pressure by outflow regulation by the orifice. , Furthermore, this fluid pressure is converted into a transmission torque between both shafts.

If you want to change this transmission torque characteristic, apply a predetermined drive command to the actuator from the outside and drive it, and the actuator operation will be converted to a spool stroke operation, and the orifice opening area that determines the outflow regulation effect will be changed to the spool. It changes depending on the relative position between the and orifice.

In this transmission torque change control, play is given to the transmission member from the actuator to the spool, the actuator is moved when the ignition is turned on, and the torque detection value from the torque detection means provided on the shaft member that transmits the rotational drive torque of the actuator is set to a predetermined value. When the value exceeds the value, the spool reference position determination means determines that the spool reference position is reached, and sets the actuator position at that time.

In other words, the shaft torque detection value is very small until gear backlash or play between transmission members is blocked, and immediately after this backlash or play is blocked, the spool's movement start resistance, which is pushed by the spring or hydraulic pressure, increases. Since the shaft torque detection value exhibits the characteristic of rapidly increasing, if the torque value that occurs when backlash or play is blocked is set as a predetermined value, the set actuator standard will be set when the torque detection value exceeds the predetermined value. The position will coincide with the spool reference position at which the spool begins the operation of changing the orifice opening area.

Then, the reference position set by the initialization process is used as the reference for the control command to be output to the actuator,
The orifice opening area is changed and controlled to obtain the transmitted torque according to the driving condition.

Note that once the ignition is turned off, the next time the ignition is turned on, the spool reference position is set again by the above-mentioned initialization process, thereby eliminating the effect of a change in the position of the actuator due to the ignition being turned off.

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

First, the configuration will be explained.

FIG. 6 is a schematic diagram showing the power train and differential limiting control system of a rear wheel drive vehicle to which the controlled rotation difference sensitive joint A of the embodiment is applied. ,
It is installed between RW and used as a differential limiting device with a built-in differential.

In FIG. 6, reference numeral 180 is a stepping motor that changes the differential limiting torque characteristic of the controlled rotation difference sensitive joint A, and this stepping motor 180 is driven and controlled by the controller 200.

This controller 200 includes a vehicle speed sensor 20.
1. Right rear wheel rotation sensor 202, left rear wheel rotation sensor 203
, steering angle sensor 204, accelerator opening sensor 205, brake switch 206, strain gauge 207 (torque detection means), etc. are connected, and these sensor signals are used as input information,
The differential limiting torque characteristic is controlled to be changed in accordance with the rotational speed difference between the left and right rear wheels, the accelerator opening degree, etc., and the differential limiting torque is controlled to be canceled when the brakes are applied.

FIG. 1 is a cross-sectional view showing a differential 1 in which a controlled rotation difference sensitive joint A is built-in. 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 left drive shafts 15 and a right drive connected to the side gears 13 and 14. A shaft 16 is provided.

The drive torque is equally distributed to the left and right drive shafts 15 and 16 when no differential rotation occurs, and when differential rotation occurs, the drive torque is driven by the differential limited torque by the control type rotation difference sensitive joint A. Torque is transmitted from the high rotation side to the low rotation side.

Hereinafter, the configuration of the control type rotation difference sensitive joint A will be explained with reference to FIGS. 1 to 4.

Among the control type rotation difference sensitive joints A, the rotation difference sensitive joint 20 exhibiting a rotation difference sensitive joint function is one of the left drive shaft 15 (first rotation shaft) and the right drive shaft 16 (second rotation shaft). A cam surface 31 formed on the inner surface of a drive housing 30 spline-coupled to one left drive shaft 15, a rotor 40 spline-coupled to the other right drive shaft 16, and a differential rotation A driving piston 50 in a radial arrangement that reciprocates in the radial direction while slidingly contacting the cam surface 31, a cylinder chamber 60 whose volume changes as the driving piston 50 reciprocates, and the cylinder chamber 6.
0 through a balance oil passage 71.
0, one end of the spool chamber 70 is opened, an accumulator chamber 90 is communicated with the cylinder chamber 60 via the regulator oil passage 80, and an accumulator chamber 90 is formed at the open end of the balance oil passage 71 with respect to the spool chamber 70. Orifice 1
00.

In addition, 32 is a drive housing cover, 41 is a cylinder hole, 42 is a relief valve hole, 51 is a seal link, 8
1 is a pole one-way valve, 91 is an accumulator piston, 92 is a spring retainer, and 93 is a return spring.

The orifice opening area changing means 110 of the aforementioned second orifice 100 includes a spool 120. Center hole 130, cross hole 140. Butsch rod 150. Crosslot 160.
It includes a slide mechanism 170 and a stepping motor 180.

The spool 120 is arranged in a spool chamber 7 such that the opening area of the orifice 100 can be changed from fully open to fully open.
0, and is arranged at the axial center position of the rotor 40.

As shown in the cross-sectional view of FIG. 3, this spool 120 is urged by an assist spring 121 in the direction of fully opening the orifice (to the left in the figure).

Note that one end of the assist spring 121 is fixed to a spring retainer 74 attached to the rotor 40 with a screw 73. Also, this spring retainer 74
A communication hole 75 is formed in the spool chamber 70 to communicate the accumulator chamber 9O and the spool chamber 70. Further, a snap ring 76 is provided in the spool hole 70 to prevent the spool 120 from popping out due to internal pressure.

The center hole 130 communicates with the spool chamber 70,
It is formed at the axis of the rotating shaft 15.

The cross hole 140 is formed to penetrate from the end of the center hole 130 in the radial direction of the left drive shaft 15.
The width of the spool 120 is set to be equal to the required stroke amount of the spool 120 and the distance between the paths.

The bushing rod 150 has one end connected to the spool 12.
0 and is inserted into the center hole 130 so as to be slidable in the axial direction.

The cross opening/end 160 is connected to the bushing rod 15.
0, and both ends are slightly protruded from the cross hole 140 to the outside of the rotating shaft 15.

The slide mechanism 170 includes a sleeve 171 connected to the cross rod 160 and provided on the outer periphery of the left drive shaft 15 so as to be slidable in the left-right direction in the figure, and a bearing 172 interposed in the sleeve 171 to prevent relative rotation. A bearing outer race 173 is provided to allow the bearing.

The stepping motor 180 is attached to the differential housing 5, and as shown in FIG. 3, a reduction gear mechanism 182 is attached to the motor shaft. A fork shaft 181 (shaft member) is connected to the output shaft 183 of this reduction gear mechanism 182, and a substantially U-shaped fork 184 is attached to this fork shaft 181. placed next to each other.

Further, the fork shaft 181 is provided with a strain gauge 207 that detects the transmitted rotational drive torque by utilizing the fact that the resistance value changes due to the torsional strain of the shaft.

Next, the effect will be explained.

(Differential limiting effect) When driving on rough roads or when one wheel is stuck, the left and right drive shafts 15.16
When a difference in rotational speed occurs between the left and right rear wheels W and RW connected to the rear wheels W and RW, relative rotation also occurs between the drive housing 30 and the rotor 40, and this relative rotation causes the driving piston 50 in sliding contact with the cam surface 31 to rotate. reciprocates in the radial direction,
When the volume of the cylinder chamber 60 is reduced by moving toward the center of the rotation axis during this reciprocating motion, the pressure inside the cylinder chamber 60 increases due to the flow resistance caused by the outflow restriction by the spool 120, and this generated oil pressure and the pressure receiving area of the piston 50 The combined hydraulic pressure becomes a force that presses the driving piston 50 against the cam surface 31, and this pressing force acts as a differential limiting torque, and in the distribution of driving torque, the high speed rotation side is reduced from the equal torque distribution. Therefore, the differential is limited to increase the low speed rotation side.

(Differential Limit Change Control) The differential limit torque characteristic of the device of this embodiment can be arbitrarily changed by changing the opening area of the orifice 100.

That is, the fork 184 is moved by the stepping motor 180.
When the bearing outer race 173 is rotated in the direction of the arrow in FIG. 1, the bearing outer race 173 slides to the right in FIG. Bush rod 150 and spool 120 are stroked to the right in the figure to reduce the opening area of orifice 100.

When the stepping motor 180 is driven in the opposite direction from this state, the fork 184 rotates in the direction opposite to the arrow, and the fork 184 no longer restricts the position of the slide mechanism 170, and the biasing force of the assist spring 121 causes the fork 184 to rotate in the opposite direction to the arrow. , bearing outer race 17
3 and the fork 184, the spool 120 also strokes to the left in the figure, and the opening area of the orifice 100 widens.

When the opening area of the orifice 100 is reduced in this way, as shown in FIG. As a result, as shown in FIG. 7, a differential limiting torque characteristic is exhibited in which the gain gradually decreases with respect to the relative rotational difference.

Therefore, for example, it is possible to improve turning performance by setting a low-gain differential limiting torque characteristic at the beginning of a turn and a high-gain differential limiting torque characteristic at the late stage of a turn, or by using a high-gain differential limiting torque characteristic when driving on a rough road or when stuck. By controlling the differential limiting torque in accordance with various driving conditions and vehicle conditions, it is possible to obtain the desired optimum driving performance, such as improving all-terrain performance.

(Spool reference position setting) Spool reference position setting is performed immediately after the ignition is turned on by initialization processing in the controller 200 using a microcomputer.

FIG. 5 is a flowchart showing the flow of the spool reference position setting process performed by the controller 200. When the ignition is turned on (step a), the stepping motor 180 is moved at a certain angle in the direction of pushing the spool 120. (step b).

Then, the output value T of the strain gauge 207 is set to the controller 200.
(step c), and its value T and set value T. (step d), and the output value T is the set value T. In the following cases, the fork 184 is connected to the sleeve 171. Cross rod 160. And the spool 120 is not pushed through the bushing rod 150. (In addition, spool 1
20 is pushed by the hydraulic pressure of the accumulator chamber 90 and stops against the snap ring 76, giving play to the transmission mechanism from the stepping motor 180 to the spool 120. ) In this case, return to step b again,
The rotation of the stepping motor 180 is advanced.

When the play in the transmission mechanism is reduced, the output value T from the strain gauge 207 reaches the set value T. The process then proceeds from step d to step f, where it is determined whether the output value T from the strain gauge 207 is smaller than the set value T1. This is to check whether the spool 120 has been pushed in beyond the play in the transmission mechanism.

If NO in step f, proceed to step 9, move the stepping motor 180 a little in the return direction of the spool 120, and repeat step C-step d-
The flow of step f is repeated, and if it is determined YES in step f, the process proceeds to step h, and the controller 20 uses the position of the stepping motor 180 at that time as the reference position.
0 random access memory (RAM) is set to 'l'.

Through the above steps, the reference positioning of the spool 120 is completed.
Thereafter, the stepping motor 180 controls the orifice opening area to change based on this reference position.

That is, by setting the torque value that occurs when there is backlash in the reduction gear mechanism 182 or play or blockage in the transmission mechanism as a set value (value from To to T), the torque value from the strain gauge 207, which is the torque detection value, can be set as a set value (value from To to T). When the output value T is within the range of this set value, the set reference position of the stepping motor 180 coincides with the spool reference position at which the sprue 120 or the orifice opening area starts changing operation.

As explained above, the controlled rotation difference sensitive joint A of the embodiment has the following features.

■ The spool reference position is set in the initialization process using the output value T from the strain gauge 207, and this set reference position is used as the reference for the control command to be output to the stepping motor 180, thereby reducing backlash of the reduction gear mechanism 182. This eliminates the influence of variations in the amount of play and play between each unit, without increasing the machining accuracy or assembly accuracy of each part.
Variations in transmission torque characteristics from unit to unit can be suppressed.

As a result, while creating a low-cost unit that does not increase the machining accuracy or assembly accuracy of each part, the orifice opening area can be finely controlled to optimally control the transmission torque characteristics according to the desired driving condition and vehicle condition. can be done in the same way for all units.

■ After the ignition is turned off, the next time the ignition is turned on, the spool reference position is set again by the upper 2 initialization process, so even if the position of the stepping motor 180 changes due to the ignition being turned off, the influence of that change can be eliminated. I can do it.

■ Output value T from strain gauge 207 which is torque detection value
Since the reference position is determined when the value is within this set value, for example, if the hydraulic pressure in the accumulator chamber 90 is released, the spool 120 will not be moved until it comes into contact with the spring retainer 74. Therefore, when the maximum rotation angle range of the stepping motor 180 is set as the reference position, a predetermined fail-safe operation such as issuing an alarm or fixing the motor rotation angle at the zero position is performed. By doing so, damage to the cam surface 31, the driving piston 50, etc. can be prevented.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and even if there are design changes within the scope of the gist of the present invention, they are included in the present invention. It will be done.

For example, in the embodiment, an example was shown in which the controlled rotation difference sensitive joint of the present invention was applied to a differential limiting device for left and right wheels. It may be used as a device or a differential limiting device for front and rear wheels.

Further, in the embodiment, an example is shown in which a stepping motor is used as the actuator, but other actuators such as a DC motor may be used.

Further, the orifice 100 may be formed in any shape such as a circle, a rectangle, an ellipse, or a triangle.

(Effects of the Invention) As explained above, in the controlled type rotation difference sensitive joint of the present invention, in the controlled type rotation difference sensitive joint in which the opening area of the orifice can be changed by an external actuator,
A spool reference position determination means is provided that determines the spool reference position based on the torque detection value of the shaft member that transmits the rotational drive torque of the actuator, so it is a low-cost unit that does not increase the machining accuracy or assembly accuracy of parts. , it is possible to obtain the effect that variations in transmission torque characteristics of individual units can be eliminated.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional plan view showing a differential to which a control type rotation difference sensitive joint according to an embodiment of the present invention is applied, FIG. 2 is a longitudinal sectional front view of the rotation difference sensitive joint taken along line I-I in FIG. The figure is an enlarged sectional view showing the sprue part of the embodiment joint, Figure 4 is a sectional view showing the stepping motor and fork part of the embodiment joint, and Figure 5 is the initialization processing operation for setting the spool reference position immediately after the ignition is turned on. FIG. 6 is a schematic diagram showing an engine drive system and control system to which the embodiment coupling is applied, and FIG. 7 is a differential limiting torque characteristic diagram using the embodiment coupling. A-... Control type rotation difference sensitive joint 15... Left drive shaft (first rotation shaft) 16... Right drive shaft (second rotation shaft) 20... Rotation difference sensitive joint 70... Spool chamber 100...-orifice 110...-orifice opening area changing means 120...
Spool 180...Stepping motor 200...Controller (including spool reference position determining means) 207...Strain gauge (torque detection means)

Claims (1)

[Claims] 1) A first rotating shaft and a second rotating shaft are coaxially arranged so as to be relatively rotatable, and the liquid is discharged according to a relative rotational speed difference between the first and second rotating shafts. The flow rate is converted into fluid pressure through outflow regulation by an orifice, and the spool is stroked using a rotation differential sensitive joint that converts this fluid pressure into transmission torque between both shafts and an actuator installed in the non-rotating part. orifice opening area changing means for changing the orifice opening area;
a torque detection means provided on a shaft member that transmits the rotational drive torque of the actuator; and a spool reference position determination for determining that the spool is at the reference position when the torque detection value from the torque detection means exceeds a predetermined value. A controlled rotation differential sensitive joint characterized by comprising means and.