JPH0341228A - Control type rotation difference sensitive coupling - Google Patents

Abstract

PURPOSE:To improve transmission torque control accuracy and control response by forming an orifice at the symmetric position at right angles to the stroke direction of a spool and by providing an orifice member to cutting off between the high pressure side and the spool. CONSTITUTION:When a relative rotation speed difference is generated between a first and a second rotation axes 24 and 22, a flow rate discharged from a cylinder chamber 60 corresponding to it is converted to fluid pressure by flow rate control by an orifice 71 and further converted to transmission torque between both the axes. In case that this transmission torque characteristic is to be changed, if a motor actuator 91 is driven by a predetermined control command, a cylinder sleeve 95 is displaced to the axial direction, and a spool 98 which is in contact with a tapered surface 95a formed on its end surface is stroked in the direction at right angles to the rotation axis without receiving high pressure by an orifice member for cutting off between the spool and the high pressure side, and an opening area of the orifice 71 at the symmetric position at right angles to its direction is changed. Thus, the transmission torque control accuracy and control response can be improved.

Description

Detailed Description of the Invention (Field of Industrial Application) 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 left and right wheels, and a differential device for front and rear wheels and left and right wheels. This invention relates to improvements in control type rotation difference sensitive joints used as differential limiting devices, etc.

(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 1. In a rotation difference sensitive joint that converts the amount of fluid discharged according to the relative rotational speed difference of the second rotating shaft into fluid pressure by restricting outflow by an orifice, and further converts this fluid pressure into a transmission torque between both shafts. , a spool is shown in which the opening area of the orifice is changed by an actuator provided on the rotating part.

(Problem to be Solved by the Invention) However, in such a conventional control type rotation difference sensitive joint, there are only a first rotating shaft and a second rotating shaft that can rotate relative to each other. The spool and actuator can be provided on the rotation center shaft, but for example,
As in the case where this joint is applied as a driving force distribution control device for a rear-wheel drive based four-wheel drive vehicle, the first. If a third rotating shaft other than the second rotating shaft exists in a penetrating state at the axis position, the spool and actuator cannot be provided at the rotational center shaft portion.

Therefore, the first. If a third rotating shaft other than the second rotating shaft exists in a penetrating state at the axial center position, as shown in FIG. A plurality of rods are arranged at positions offset from the rotation axis center position so as to surround the third rotation axis, and spools are provided at the tips of the plurality of rods, and the opening area of the orifice can be changed by the stroke position of the spool. There is a proposal to do so.

However, even the controlled rotation differential sensitive joint shown in FIG. 7 has the following problems.

■ There is a one-to-one relationship between the amount of rod operation and the amount of slide stroke of the spool, so when closing or opening the orifice opening area by a minute amount with the spool, the amount of rod operation by the actuator will also be the same. The amount must be minute, and it is difficult to control the transmission torque characteristics with high precision by changing the opening area of the orifice.

■ Since the orifice exists in only one direction relative to the spool, the spool is pressed against the spool chamber due to unbalance in the radial direction, increasing spool sliding resistance and causing a delay in response.

The present invention has been made in view of the above-mentioned problems, and provides a control type rotation differential sensitive joint in which the opening area of an orifice can be changed by an external actuator. It is an object of the present invention to be applicable to a case where a third rotating shaft exists in a penetrating state at the axial center position in addition to the second rotating shaft, and to obtain high transmission torque control accuracy and high control responsiveness.

(Means for Solving the Problems) In order to solve the above problems, in the control type rotation difference sensitive joint of the present invention, a cylindrical sleeve is arranged on the outer periphery of the third rotating shaft, and a Teva surface formed on the cylindrical sleeve is provided. A slide stroke is applied to the spool through the spool, an orifice is formed at a symmetrical position perpendicular to the stroke direction of the spool, and an orifice member is provided to isolate the high pressure side from the spool.

That is, a first rotating shaft and a second rotating shaft are coaxially arranged so as to be relatively rotatable; a third rotating shaft disposed penetratingly at a rotational axis center position coaxial with the second rotating shaft; 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 actuator provided in the non-rotating part; a cylindrical sleeve disposed around the outer periphery of the third rotating shaft and subjected to axial displacement by actuator operation; An orifice opening area change that includes a spool that is movable in a direction perpendicular to an axis, and an orifice member that has an orifice formed at an operating position perpendicular to the stroke direction of the sprue and blocks a high-pressure side from the spool. It is characterized by having the means and.

(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 controlled by the orifice and the fluid pressure is adjusted. This fluid pressure is then converted into a torque transmitted between the two shafts.

When changing this transmission torque characteristic, when the actuator provided in the non-rotating part is driven by a predetermined control command, an axial displacement is applied to the cylindrical sleeve, and the taper formed on the end surface of the cylindrical sleeve is The spool in contact with the surface strokes in the direction perpendicular to the rotation axis without receiving high pressure from the orifice member that blocks the high-pressure side and the spool, and the opening of the orifice is formed at a symmetrical position perpendicular to the stroke direction of the spool. Area is changed.

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

First, the configuration will be explained.

Fig. 5 is a skeleton diagram showing the power train of a four-wheel drive vehicle to which the control type rotation difference sensitive joint A of the embodiment is applied.The control type rotation difference sensitive joint A directly drives the rear wheels with the engine placed horizontally. It is installed in the middle of the power transmission path to the front wheel drive system of a four-wheel drive vehicle as a joint that serves both as a center differential and as a drive force distribution control device for the front wheels.

In FIG. 5, the rear wheel drive system includes an engine 1, a transmission (including a clutch) 2, a first rotating member 24 (first rotating shaft) driven by the final gear 21 of the transmission 2, and a transfer gear train 9.
, a propeller shaft joint 13, propeller shafts 10, 11° 12, a rear differential 15, a rear drive shaft 16, 17, and a rear wheel 19, 20. As a front wheel drive system, a first Rotating member 24, controlled rotation difference sensitive joint A, second rotating member 22 (second rotating shaft) integrated with the front differential case, front differential 3, left front drive shaft 4 (third rotating shaft),
Right front drive shaft 5, joint 6, front wheel 7
．． It is equipped with 8.

1 and 2 are cross-sectional views showing a control type rotation difference sensitive joint A.

Of this control type rotation difference sensitive joint A, the first. The flow rate discharged according to the relative rotational speed difference (rotational speed difference ΔN between the front and rear wheels) of the second rotating member 24.22 is converted into oil pressure by outflow regulation by an orifice, and this oil pressure is further transferred to the circumferential rotation member 22.24. Transmitted torque between (transmitted torque to front wheel side △T
) The configuration of the rotation difference sensitive joint section that shows the function of distributing drive force between the front and rear wheels will be explained.

This rotation difference sensitive joint part includes a dry housing 30 spline-coupled to the first rotation member 24 and having a cam surface 31 formed on the inner surface, a rotor 40 spline-coupled to the second rotation member 22, and a rotor 40 spline-coupled to the circumferential rotation member 22. , 24, a radially arranged driving piston 50 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 60. a spool chamber 72 communicated with the spool chamber 72 via a communication passage 70 and an orifice 71; an accumulator chamber 100 communicated with the spool chamber 72 via a communication oil passage 73; and a regulator chamber 100 communicated with the cylinder chamber 60 from the accumulator chamber 100. An oil passage 80 is provided.

In addition, in FIG. 1 and FIG. 2, 42 is a cylinder hole,
43 is an oil seal, 51 is a piston seal ring, 8
1 is a one-way pole valve, 101 is a piston seal ring, 102 is an accumulator piston, 103 is a spark retainer, 104 is a return spring, +10
is a relief hole.

The configuration of the orifice opening area changing means for changing the opening area of the orifice 71 in the control type rotation difference sensitive joint A will be described.

This orifice opening area changing means includes a motor actuator 91 provided in the transaxle case 23 (non-rotating part) and a motor shaft 9+a of the motor actuator 91.
A fork 94 (swinging member) connected to the fork 94 via a speed reducer 92 and a fork shaft 93, and a fork 94 (swinging member) disposed on the outer periphery of the left front drive shaft 4, which is axially displaced to change the opening area of the orifice 71 from the fork 94. a cylindrical sleeve 95 provided with a cylindrical sleeve 95, a sliding piece 96 coupled to the fork 94 via a bottle, a sliding piece engagement groove 97 formed at the actuator side end of the cylindrical sleeve 95, and a joint side of the cylindrical sleeve 95. Tapered surface 95a formed at the end
a spool 98 disposed in contact with and movable in a direction perpendicular to the rotation axis; and an open outer cylindrical end 98 of the spool 98.
has a closed inner cylindrical end 99a corresponding to the subur 9
Orifice 7 is located at a symmetrical position orthogonal to the stroke direction of 8.
1 is formed.

The fork 94 is fixed to the fork shaft 93 by a key 94a, as shown in FIG. It is arranged while allowing.

As shown in FIG. 1, the cylindrical sleeve 95 is inscribed in the rotor 40, allowed to slide relative to the rotor 40 by means of a key 95b, and is provided so as to rotate together with the rotor 40.

As shown in FIG. 3, the spool 98 has a spherical surface 98b on the surface that contacts the tapered surface 95a of the cylindrical sleeve 95, and a seal ring 98c is provided on the outer periphery to maintain an oil-tight state with the inner wall of the spool chamber 72. It is being

The spool 98 has a relief oil hole 98d formed in the open outer cylindrical end 98a in order to ensure a stroke with respect to the orifice part 99.

The orifice part 99 has a closed inner cylindrical end 99a that is closed to the high pressure side (cylinder chamber 60 side) (bag-like shape), and the spool chamber 72 is closed by the closed inner cylindrical end 99a. The relief oil hole 98d communicates with the connecting oil passage 73, but forms a space that is cut off from the communication passage 73 on the high pressure side. Date spring 99b biases the lower surface of orifice part 99 upward in FIG.
A seal ring 99b is provided on the outer periphery of the spool chamber 72 to maintain an oil-tight condition with the inner wall of the spool chamber 72.

As shown in FIG. 3, an open outer cylindrical end 98a located on the low pressure side (spool chamber 72 side) is fitted into a closed inner cylindrical end 99a that is closed to the high pressure side. However, by stroking the spool 98 while maintaining this fitted state, the opening area of the orifice γ1 is changed.

Next, the effect will be explained.

When driving on a low friction coefficient road such as a two-way road or an icy and snowy road, when a difference in rotational speed between the front and rear wheels occurs in which the rear wheels, which are directly connected to the engine, slip, the first rotating member 24 of the rear wheel drive system and the front wheel drive system are rotated. Relative rotation occurs between the second rotation member 22 and the drive housing 30 of the rotation difference sensitive joint portion and the rotor 40 rotate relative to each other due to the generation of this relative rotation.

This relative rotation causes the driving piston 50 in sliding contact with the cam surface 31 to reciprocate in the radial direction, and during the piston stroke toward the center of the rotation axis, the discharge flow rate is reduced by reducing the volume of the cylinder chamber 60. is converted into hydraulic pressure by the outflow regulation by the annular orifice 71, the pressure inside the cylinder chamber 60 increases, and the hydraulic pressure obtained by multiplying this generated hydraulic pressure and the pressure-receiving area of the piston 50 is a force that presses the driving piston 50 against the cam surface 31. Therefore, this pressing force acts as a torque transmitted to the front wheel side.

In this embodiment, by changing the opening area of the orifice 71, the characteristics of the torque Δd to be transmitted to the front wheels can be arbitrarily changed.

That is, the motor actuator 91 provided in the transaxle case 23 is driven by a predetermined control command,
When the fork 94 is rotated to the right in Fig. 1,
The cylindrical sleeve 95 strokes to the right in FIG. 1, and for a stroke amount S1 of the cylindrical sleeve 95, as shown in FIG. It strokes downward in the drawing while being held down by 95a.

Furthermore, when the fork 94 is rotated to the left in FIG. 1, the cylindrical sleeve 95 strokes to the left in FIG. The spool 98 strokes upward in FIG. 3 while maintaining contact with the tapered surface 95a due to the oil pressure in the chamber 100.

During this spool stroke, orifice part 99
is closed to the high pressure side (cylinder chamber 60 side) by its closed inner cylindrical end 99a, and high pressure from the cylinder chamber 60 does not act on the end surface of the spool 98. Unlike the case where the end face is open to the cylinder chamber 60, a large load is not required for the sliding operation of the spool 98, and pressure fluctuations in the cylinder chamber 6o do not directly affect the spool load fluctuation.

By this spool stroke operation, the opening area of the orifice 71 can be controlled to an appropriate area from the maximum opening area shown in the left half of FIG. 3 to the fully closed state shown in the right half of FIG. can.

As a result, as shown in FIG. 6, by changing the opening area of the orifice 71, it is possible to change the characteristics of the torque transmitted to the front wheels. By doing so, you will also be able to achieve excellent performance as listed below.

a) Tight corner braking is prevented by setting the opening area of the orifice 71 large during small radius turning on a dry road, and by making the distribution of driving force to the front wheels small relative to the front and rear wheel rotational speed difference ΔN.

b) By setting the opening area of orifice γ1 small when driving on a road with a low friction coefficient, and by making the driving force distribution to the front wheels large relative to the rotational speed difference ΔN between the front and rear wheels, it is possible to achieve high running performance on roads with a low friction coefficient. can get.

C) High starting performance and acceleration performance can be obtained by setting the opening area of the orifice 71 small at the time of starting or during intermediate acceleration, and by making the driving force distribution to the front wheels large relative to the front and rear wheel rotational speed difference ΔN.

d) By setting the opening area of the orifice 71 to be small during high-speed running, and having a characteristic that the driving force distribution to the front wheels is large relative to the front and rear wheel rotational speed difference ΔN, high-speed running stability and high turning limit performance can be obtained. It will be done.

e) When the vehicle is stuck, the orifice 71 is fully closed and the driving force distribution characteristic is applied to rigid 4WD, thereby improving the ability to escape from the vehicle.

f) When a large rotational speed difference ΔN between the front and rear wheels continues, such as when driving for a long time on sandy or muddy ground, the orifice 71 is fully closed to suppress the heat generation of the oil and reduce heat. It is possible to protect weak parts and prevent shortening of product life.

As explained above, the control type rotation difference sensitive joint A of the embodiment
It also has the features listed below.

■ Since the motor actuator 91 is installed in the transaxle case 23 and the cylindrical sleeve 95 is placed at an offset position on the outer periphery of the left front drive shaft 4, the first
．． The orifice opening area changing means can be applied even though the left front dry shaft 4, which is the third rotating shaft, is present in a penetrating state at the axial center position in addition to the second rotating members 22 and 24.

As a result, a driving force distribution control device having excellent performance as described in a) to f) above can be provided.

■ Since the spool 98 is configured to slide through the tapered surface 95a formed on the cylindrical sleeve 95, the slide stroke S2 of the spool 98 is a fraction of the stroke amount S1 of the cylindrical sleeve 95. , the opening area of the orifice 71 is the spool 98
When the cylindrical sleeve 95 is closed or opened by a small amount by the motor actuator 91,
SI can be increased.

As a result, the transmission torque characteristics can be controlled to be changed with high precision by changing the opening area of the orifice 71.

(2) Since the orifice 71 is provided at a symmetrical position orthogonal to the stroke direction of the spool 98, the hydraulic pressure acting on the spool 98 via the orifice 71 is balanced and canceled, and the force that presses the spool 98 against the spool chamber 72 does not act.

Also, the orifice part 99 is connected to its closed inner cylindrical end 99.
a to the high pressure side (cylinder chamber 6o side) and the spool 98.
Since the spool chamber 72 with low pressure is formed below the spool 98, the high pressure from the cylinder chamber 60 does not act on the end face of the spool 98, and the sliding movement of the spool 98 requires a large load. Moreover, pressure fluctuations in the cylinder chamber 60 do not directly affect spool load fluctuations. As a result, the spool load applied to the spool 98 by the motor actuator 91 is small in terms of load level, and the variation range is also small, and the transmission torque characteristic change control by changing the opening area of the orifice 71 is always performed with stable and high response. be able to.

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 the present invention may be modified without departing from the gist of the present invention. included.

For example, in the embodiment, an example was shown in which the controlled rotation difference sensitive joint of the present invention was applied as a driving force distribution device for a four-wheel drive vehicle. It may also be applied as a differential device, etc.

Further, the opening shape of the orifice may be any shape such as a circle, a rectangle, an ellipse, or a triangle.

(Effects of the Invention) As explained above, in the present invention, in a controlled rotation differential sensitive joint in which the opening area of the orifice can be changed by an external actuator, a cylindrical sleeve is arranged around the outer periphery of the third rotating shaft. and applying a sliding stroke to the spool via a tapered surface formed on the cylindrical sleeve,
First, because orifices are formed at symmetrical positions perpendicular to the stroke direction of the spool, and an orifice member is provided that blocks the high-pressure side from the spool. The present invention can be applied to a case where a third rotating shaft exists in a penetrating state at the axial center position in addition to the second rotating shaft, and has the effect that high transmission torque control accuracy and high control responsiveness can be obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view (cross-sectional view taken along the line I--I in FIG. 2) showing a controlled rotation differential sensitive joint according to an embodiment of the present invention, and FIG.
[A longitudinal sectional front view taken along the line -II, FIG. 3 is an enlarged sectional view showing the orifice part of the orifice opening area changing means of the embodiment joint, and FIG. 4 is a motion conversion mechanism of the orifice opening area changing means of the embodiment joint. Fig. 5 is a skeleton diagram showing the engine drive system of a four-wheel drive vehicle to which the embodiment joint is applied, and Fig. 6 shows the torque to the front wheel side due to the rotation speed difference between the front and rear wheels due to the embodiment joint. Transfer characteristic diagram, 7th
Figure 1. FIG. 7 is a longitudinal sectional side view showing an example of a control type rotation difference sensitive joint in which a third rotating shaft exists in a penetrating state at the axis position in addition to the second rotating shaft. A...Controlled rotation difference sensitive joint 4...Left front drive shaft 22...Second rotating member (second rotating shaft) 23...Transaxle case (non-rotating member) 24...No. One rotation member (first rotating shaft) 71... Orifice 91... Motor actuator (actuator) 94... Fork 95... Cylindrical sleeve 95a... Tapered surface 8... Spool 8a... Open outer cylindrical end 9... Orifice parts (orifice member) 9a... Closed inner cylindrical end

Claims (1)

[Scope of Claims] 1) A first rotating shaft and a second rotating shaft that are coaxially arranged so as to be relatively rotatable; The flow rate discharged according to the relative rotational speed difference between the third rotating shaft arranged in the state and the first and second rotating shafts is converted into fluid pressure by outflow regulation by an orifice, and further, this fluid pressure is a rotational difference sensitive joint that converts the torque into a transmission torque between both shafts, an actuator provided in the non-rotating part, and a cylindrical sleeve disposed on the outer periphery of the third rotating shaft and subjected to axial displacement by actuator operation. , a spool that is in contact with a tapered surface formed on an end surface of the cylindrical sleeve and is movable in a direction perpendicular to the rotation axis; an orifice is formed at a symmetrical position perpendicular to the stroke direction of the spool; What is claimed is: 1. A controlled rotation differential sensitive joint, comprising: orifice opening area changing means having an orifice member that blocks the connection between the spool and the spool.