JP3455310B2 - Power case - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the power case of a drive mechanism of a motor vehicle, and more particularly to a predetermined speed of the motor vehicle, preferably for the purpose of preventing excessive assistance to the driver, which would endanger the operation of the motor vehicle. Is an improvement on a type of power case that is fast and automatically transforms the power case into a fully mechanical case.

[0002]

2. Description of the Related Art Power cases for drive mechanisms or servosteering are known which reduce the power required for parking operations, in particular for stopping the vehicle and rotating the wheels or rotating it at low speeds. Is.
These mechanisms operate in a similar manner to conventional gear steering wheels, except that they have a piston that works with a rack bar, which piston is selectively connected via a valve coupled to a pinion. This automatic control is performed when the steering wheel is driven by the driver's steering by being driven in one direction or the other direction by the supplied pressurized fluid.

[0003] These power cases serve a particular purpose, to which power cases are assigned, especially at low speeds, but over-assist the driver during high-speed maneuvers and, in case of unexpected maneuvers, motor vehicles. Lose control over. A mechanism in which the power case of such a drive mechanism constantly assists at high speed or low speed is a serious problem.

In order to solve this, an improvement in the function in such cases was made, which was to control the fluid passage through the distributor valve to reduce the auxiliary effect, or of the pressure fluid pump. Limited to selectively adjusting the action to reduce the fluid supply, in all cases the drive mechanism, to some extent, survives operational problems at high speeds to assist the driver. become. The ideal solution to the problem consists of modifying the mechanism in terms of its optimal behavior by acting as a power case at low speed and as a fully mechanical case at high speed.

For the above reasons and to achieve the above objects, the present invention assembles an integral assembly between all parts of the case acting as a conventional drive mechanism to obtain a non-actuated state. To do so, it proposes a power case for a variable-functionality drive mechanism that responds faster than a predetermined value, with a gradual and gradual angular interaction of the valve spool and pinion.

In order to fully understand the proposed solution, it is advantageous to have the structural and functional characteristics of a conventional power case, as shown in. This type of case has a steering case 1 in which a cylinder 2 is incorporated inside, one end is welded and sealed, and a piston 3 fixed to an end portion of a rack bar 4 is attached.
Is coaxial with the casing 1 and extends beyond the cylinder 2 and is operatively associated with a pivot arm (not shown) to form a steering mechanism.

The casing 1 has a case body 1 ',
A valve 5 is attached to the case main body 1 ', and a pressurized fluid distributor formed by a valve spool 5'having a rotary support inside the case and a valve sleeve 5'coaxial with the valve spool 5'. Have.

The valve spool 5'has an orifice 6 in its upper portion, which communicates with the supply circuit for pressurized fluid and the valve spool 5 ', and the inside of the valve spool 5'has a valve sleeve 5'. It has an opening orifice corresponding to 〃, which corresponds to the inside of the valve spool 5'while the case is functioning, and assists during the steering operation by the conduits on both sides of the piston. Form a fluid passage. The valve spool 5'has an upper portion attached to the column of the steering wheel and a toothed lower portion 5a which meshes with the toothed inner portion of the bushing 8 provided on the case body 1 '.

There is a clearance between the two teeth, which allows the valve spool 5'of the valve 5 to
It allows angular rotational movement of the base of a bushing 8 which is connected to the valve sleeve 5 "of the valve 5 and projects the pinion 4'in engagement with the rack bar 4. Inside the valve spool 5 ', coaxial therewith, one end On the upper portion of the valve spool 5 ', a torsion bar 9 fixed to the base of a bushing 8 having the other end connected to the valve sleeve 5 "is attached. When the steering wheel turns, this conventional method of operating a power case starts, and this movement is transmitted to the pinion via the torsion bar 9. The torsion of the torsion bar 9 causes a slight difference in the axial displacement of the pinion 4 with respect to the pinion, and in response to this difference, a difference in the valve spool 5'with respect to the valve sleeve 5 "of the valve 5 and the piston of the rack bar 4 Pressurized fluid is passed to one or the other side of 3, to obtain an auxiliary effect in this way.

[0010]

SUMMARY OF THE INVENTION The present invention provides an improvement over conventional power cases such as those described above, which basically comprises the steps of incorporating a mechanism to eliminate the angular clearance caused by torsion bars. This mechanism comprises a blocking device which forms an integral part of the power case and progressively blocks the function of the torsion bar, the progressive blocking device having a width of approximately 7 ° in one or the other direction of the steering wheel. Changes the valve spool angle.

The torsion bar blocking device interferes axially or transversely with the torsion bar and preferably is electrically responsive to the control signals of the wheel speed sensor and the steering wheel torque sensor. Actuator. This is the existing part of the case, until its overall stiffness constitutes a conventional mechanical case in response to a signal generated by the wheel's speed sensor, so as to form a coupling assembly by this method. It is meant that this mechanism automatically responds to certain values or parameters, speed or torque, starting from a given speed to provide a gradual block of the torsion bar. Also, this mechanism starts from this state,
It acts as a power case by restoring hydraulic assistance in response to torque values generated by the driver at high speed and unpredictable behavior. That is, in this second state, the torque signal triggers the unblocking of the torsion bar.

In practice, an improvement of the present invention is that the valve has a fixed part at the end of the torsion bar opposite the end fixed to the valve spool, the fixed part having an angle of It is a clearance limiting means, has a prismatic shape having a recess on the side opposite to the side on which the torsion bar is fixed, and has side slopes facing each other that determine the limit on the angular clearance of the valve spool. The fixed portion is fixed laterally to the bushing holder of the pinion by a pin and is loosely enclosed in a groove formed in the cylindrical end portion of the valve spool. This groove limits a pair of symmetrical parts which are located in that part with respect to the axis of the valve spool and which are arranged concentrically with respect to the bushing, but with a free angular clearance which is restricted by the fixed part of the torsion bar. . The fixed portion of the torsion bar is arranged at the bottom of the groove of the valve spool between the flat and parallel surfaces of the groove inner surface of the end of the valve spool, and the flat and parallel surface is an inclined surface inclined toward the end of the fixed portion. Are formed and are arranged at a position deviated by 90 ° with respect to the groove of the valve spool. The portion of the valve spool where the groove is formed and the fixed portion of the torsion bar that forms the recess that extends to the bottom of the bushing define the guide space of the fixed dowel of the fixed portion, and the fixed dowel is the end of the rod coaxial with the pinion. Fixed to the section, arranged for free axial movement in the passage of the pinion, extending from the bottom of the bushing to the end of the rotary support of the pinion, the rod projecting beyond the steering case.

The fixed dowel of the fixed portion has a pair of opposed inclined surfaces, the inclined surfaces having a small conical shape corresponding to the conical area of the valve spool, and the pair of flat parallel surfaces being: Face the facing surface of the recess in the fixed part of the torsion bar. Accordingly, the angular clearance of the valve spool is gradually limited by the axial movement of the dowel when the conical portion of the valve spool and the conical portion of the dowel portion meet. The dowel is dominated by an electrical device which is actuated by the speed sensor of the wheel and the sensor of the steering wheel via the rod.

The proposed improvement is to act as a power case at low speeds and as a conventional mechanical case at high speeds to provide fast and immediate assistance in response to sudden maneuvers required to avoid obstacles. Has a power steering variable device that can be restored to. Therefore, the present invention is a power case for a steering mechanism of an automobile having a steering casing having an inner cylinder, in which the piston fixed to the end of the rack bar is arranged in the inner cylinder, The rack bar extends coaxially with the casing and projects to the outside of the casing, and is connected to an articulated arm of a wheel control system, the casing distributing auxiliary fluid in response to rotation of a steering wheel. In fluid communication with the housing body of the fluid valve, the distributor valve being formed by a tubular valve spool, the upper portion of which is connected to the steering column of the vehicle and is in fluid communication with the fluid source. A valve sleeve concentric with the valve spool and having an inlet and a return orifice. An orifice selectively communicating with a passage in a case that communicates both sides of the piston with the supply through a port of the valve spool in response to rotation of a steering wheel, and a lower portion of the valve spool is It is concentrically arranged with respect to the bushing attached to the case and connected to the valve sleeve, and is connected to the bushing and is freely angled in both directions by a torsion bar in response to being driven by rotation of a steering wheel. The torsion bar is disposed coaxially with the valve spool, and both ends of the torsion bar are connected to the valve spool and the bushing, respectively, and the bushing is disposed in a meshing relationship with the rack bar. Steering coupled to a fixed pinion In the power case of the structure, the end of the torsion bar opposite to the end connected to the valve spool is coupled to a fixed portion for the torsion bar provided on the valve spool mounted inside the bushing, The fixed portion is connected to a bushing at a side thereof, and is disposed at a bottom portion of a groove provided in a cylindrical end portion of a valve spool concentrically arranged on the bushing, and the groove is Both sides of the fixed part have a slightly clearance surface and their lateral edges limit the angular rotational movement of the valve spool in both rotational directions during hydraulic assistance of the mechanism. A device forming a torch inside the bushing movably coupled to the control device of the torsion bar in response to the values of wheel speed and steering wheel torque. A block device for the steering bar is installed, the block device gradually reduces the angular clearus of the valve spool, and the torsion bar and the valve spool transmit the movement of the steering wheel directly to the pinion of the rack bar. It is characterized by forming an integral mechanical unit.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In all the figures shown, the same reference numbers refer to equal corresponding parts. In particular, the improvement proposed by the invention, shown below, has been incorporated into a conventional case as represented by and has a fixed part 10 of the torsion bar 9, which is at one end of the valve spool 5 '. A rod 11 'coaxially attached to it to limit the angular clearance of the dowel 11 and to provide free axial movement with a bushing 8 integrally formed with the pinion 4'. Is attached to the end of and serves to block the fixed part 10.
The improvement of the invention also comprises a valve spool 5'having a cylindrical end portion 12 longitudinally divided by a groove 13. The valve spool 5'is a cylindrical end portion which is longitudinally divided at the end portion by a groove 13 which forms portions 14, 14 'of symmetrical shape with respect to the geometrical axis e of the valve spool 5'. It has (12).

These parts 14 of the valve spool 5 ',
14 ′ is constituted by mutually parallel flat surfaces 15, 15 ′ which are symmetrically opposed to each other with respect to the axis e, and these flat surfaces 15, 15 ′ are formed by the grooves 13 with which the torsion bar 9 intersects.
Slopes 16 that start from the bottom 13 'of the
16 ', these inclined surfaces 16, 16' form a cone in the valve spool 5'between the parts 14, 14 '. The fixed part 10 of the torsion bar 9 is constituted by a flat polygonal U-shaped body, the free branch parts 17, 17 'of which are at right angles between the intermediate branch part 19 and the branch parts 17, 17'. Form a depression c limited by a face.

The fixed portion 10 is such that the opposing flat surfaces 10, 10 "having a thickness or height less than the separation distance of the flat, parallel flat surfaces 15, 15 'of the valve spool are also flat and parallel. , With a slanted longitudinal edge 19. The fixed part 10 is laterally connected to the bushing 8 of the power box by a pin 20 at the bottom 13 'of the groove,
The flat surfaces 15, 15 'of the space h of the groove 13 limit the flat surfaces 10', 10 "of the fixed part 10. As can be seen, the parts 14, 1 of the end part 12 of the valve spool 5 '.
4'is supported on the bottom of the bushing 8 and is part 14,1
4'and the branch part 1 displaced by 90 ° with it
7 and 17 'define the inclined surfaces 16, 16' and the depression c of the fixed part 10.

These inclined surfaces 16, 16 'and the surfaces of the branch parts 17, 17' form a longitudinal guide of the dowel 11, which is the conical inclined surface 16 of the parts 14, 14 '. , 16 ′, and a surface parallel to the fixed portion 10 and a side inclined surface. Both sides of the dowel 11 facing the conical inclined surface present the same conical shape as in the area of the inclined surfaces 16, 16 ', which begins at the same intersection as the flat parallel surfaces of the parts 14, 14'. 11 fits tightly between both conical inner surface ends at the end of its run, but when it is arranged in the region of the end inclined surfaces 16, 16 ', said inclined surface 16 , 16 'form a clearance or space h'.

The dowel 11 is arranged coaxially with the housing 8 on the rod 11 ′ so as to be free to move axially in the passage 18 starting from the bottom of the bushing 8 in the pinion 4 ′. It projects beyond the drive case 1 and is associated with a selective positioning device for the dowel 11 in the recess c in response to the wheel speed and the steering wheel torque. These devices, indicated by reference numeral 19 in FIG. 1, may be of different configurations and do not form part of the present invention. As an example, they are constituted by an electrical device, which has an electromechanical actuator 20 dominated by the output of a signal comparator of a circuit 21, not shown in detail, the input of which is the wheel. A speed sensor 22 and a torque sensor 23 for the steering wheel v of the drive column connected to the valve spool 5 '.
Connected to. The operation of the improvement incorporated in the power case to selectively convert the power case to the mechanical case is as follows. In the normal linear movement of a motor vehicle, when the valve 5 is in a non-actuated state, that is, the passages for connecting the hydraulic circuit to both sides of the piston 3 fixed to the rack bar 4 have a valve spool 5'and a valve sleeve of the valve 5. There is no hydraulic assistance when blocked between 5 ".

In this position of the dowels 11, the dowels 11 are located at the rear end of the depression c, ie their inclined surfaces are separated by a clearance or space h '. In this position, the power case operates conventionally. That is, when the steering wheel rotates in one direction or the other, the movement of the steering wheel
Is transmitted to the pinion 4 '. The twisting of the torsion bar 9 fixed at its upper end to the valve spool 5'causes an angular displacement of the valve spool 5'limited by the fixed portion 10 of the bar, which is done as follows. Portion 1 of the cylindrical end portion 12 of the valve spool 5 '
The fixed parts 1 and 4 are moved by an angle of about 7 °.
Beveling of the longitudinal edge 19 of the valve spool 5 '
This angular movement α limited to the fixed part 10 on both sides to allow communication of the passage between the valve sleeve 5 ″ and the valve sleeve 5 ″.
Is performed, which allows the auxiliary fluid to pass through the steering casing 1.

In high speed and light operation, the power case is
Maintaining its functionality, the driver receives excessive assistance while driving. In this state, the proposed improvement forms a case deformation in a conventional mechanical case or box. For this purpose, the wheel speed sensor 22 starts to actuate from a predetermined speed and generates a control signal for the actuator 20, whereby a depression c is formed between the conical ramps 16, 16 '. The movement of the rod 11 'along it results in the movement of the dowel 11, which movement is caused by the movement of the surface of the dowel 11 and the parts 14, 1 of the valve spool 5'.
4'abut against each other and complement each other tightly and gradually reduce the angle α until they join the parallel surfaces of the fixed part 10 of the torsion bar 9.

In this position of the dowel 11, an integral unit is formed in the case, a bushing 8 having a valve spool 5 ', a valve sleeve 5 "and a pinion 4'.
The fixed part 10 and the torsion bar 9 act when blocking the torsion bar 9, i.e. to join as a mechanical case, which is the valve spool 5 '.
It means eliminating hydraulic assistance by eliminating the angular clearance of. In this abutting position of the dowel 11, in a high-speed vehicle, if the driver makes an unexpected movement with a torque value above the predetermined value of the sensor 23 related to this torque, it is the control signal of the actuator 20. Is generated, the rod 11 'is pulled by the signal, the dowel 11 is deactivated, and the case is converted to the power case. The blocking of the valve spool 5 ′ and the torsion bar 9 is carried out axially, but it can also be carried out in a direction transverse to the torsion bar 9. Although the invention has been described above, the invention is clearly understandable to a person skilled in the art and requires no further explanation.

[Brief description of drawings]

1 is a cross-sectional view of a power case incorporating the improved portion of the present invention.

FIG. 2 is an enlarged detailed view of the mechanism of the present invention, in which the power case responds to hydraulic resistance in a non-actuated state, the mechanism of the present invention blocking the torsion bar to eliminate the angular gap in the center of the valve. Is.

FIG. 3 is a cross-sectional view through the line I-I showing the center of the valve of the case in the unassisted drive position.

FIG. 4 is a cross-sectional view similar to showing a central angular gap in response to rotation of a steering wheel actuated by a torsion bar.

FIG. 5 is a cross-sectional view through the line II-II showing the fixed dowels of the fixed portion of the torsion bar between the valve spool and the conical surface of the gap or space towards these surfaces.

FIG. 6 is a similar drawing showing a fixed dowel at a fixed portion at a midpoint of traveling, that is, a fixed dowel that gradually reduces an angular gap of a torsion bar.

FIG. 7 shows the reduction of the space between the fixed dowel of the fixed part and the central conical surface, which is the line III of the auxiliary reduction.
It is a sectional view which passes along III.

FIG. 8 shows the reduction of the space between the fixed dowel of the fixed part and the central conical surface, which is the line III of the auxiliary reduction.
It is a sectional view which passes along III.

FIG. 9 is a view showing a mechanism of the present invention showing a dowel at a block position of a fixed portion of a torsion bar.

FIG. 10 is a cross-sectional view through line IV-IV showing the dowel in the overall block position without clearance for the central cone of the valve.

FIG. 11 is a perspective view of parts of the mechanism of the present invention.

FIG. 12 shows a power case with conventional components for understanding the interpretation of the invention.

[Explanation of symbols]

4 pinion 5'valve spool 8 bushings 9 torsion bar 10 fixed 11 fixed dowel 12 Cylindrical end 13 groove 15,15 'flat surface 16,16 'inclined surface 17,17 'Branch 20 actuators 22 sensors 23 sensors

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-19268 (JP, A) JP-A-60-110570 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 5/083 B62D 5/06

Claims (6)

(57) [Claims] 1. A power case for a steering mechanism of an automobile having a steering casing having an inner cylinder, wherein a piston fixed to an end of a rack bar is arranged in the inner cylinder, The rack bar extends coaxially with the casing and projects to the outside of the casing, and is connected to an articulated arm of a wheel control system.
In response to rotation of the steering wheel, it communicates with the housing body of the auxiliary fluid distributor valve, said distributor valve being formed by a tubular valve spool, the upper part of which is connected to the steering column of the vehicle. A fluid inlet and a return orifice in communication with the source of fluid and concentric with the valve spool by a valve sleeve that is responsive to rotation of the steering wheel to the source through the port of the valve spool. An orifice that selectively communicates with a passage of a case that communicates both sides of the piston is formed, and a lower portion of the valve spool is concentrically arranged with respect to a bushing attached to the case and connected to the valve sleeve. And connected to the bushing by turning the steering wheel In response to being moved, the torsion bar is capable of freely performing an angular movement in both directions, the torsion bar being coaxially arranged on the valve spool and having ends on both sides respectively a valve spool and a bushing. An end of a torsion bar opposite to an end connected to a valve spool in a power case of a steering mechanism of an automobile, wherein the bushing is connected to a pinion arranged in a meshing relationship with the rack bar. The part is connected to a fixed part for a torsion bar provided inside the bushing, said fixed part being connected to the bushing on the side and having a cylindrical shape of a valve spool concentrically arranged on said bushing. It is arranged at the bottom of the groove provided in the end part,
The groove faces both sides of the fixed part and has a surface with a slight clearance, and its lateral edges have an angular rotation of the valve spool in both rotational directions during hydraulic assistance of the mechanism. A blocking device for a torsion bar is mounted on the inside of the bushing, which forms a device for limiting the movement, and which is movably connected to a positioning device responsive to the value of the wheel speed and the torque of the steering wheel. The block device is selected by the positioning device.
Angle clearer of the preparative valve spool is controlled to択的
Emission scan is gradually decreased gradually, and the valve spool and the torsion bar, and characterized in that to be able to form an integral mechanical unit directly transmitting the movement of the steering wheel to the rack bar of the pinion Power case for automobile steering mechanism. 2. The fixed portion of the torsion bar has flat surfaces on both sides which are parallel to each other, and each of these flat surfaces has a prismatic shape having an inclined region converging toward a vertical symmetric center plane in the longitudinal direction. The main body, the flat surface being located at a slight distance from the flat bottom surface of a groove provided in the cylindrical end portion of the valve spool, the groove being a fixed portion of the end portion of the torsion bar. The body has a depth from the upper end surface to the lower end surface, and the body is provided with an indentation, and the indentation defines a pair of branch portions having inward faces parallel to each other and orthogonal to a bottom surface of the indentation. Then
The power case according to claim 1, wherein the main body of the fixed portion is connected to a wall of the bushing by a pin laterally fixed to the bushing. 3. A groove formed in a cylindrical end portion of the valve spool is a branch portion of a fixed portion of a torsion bar.
Define a pair of longitudinal portions of the cylindrical end portion that extend longitudinally offset by 90 ° and are symmetrically opposed, and the groove in the cylindrical end portion of the valve spool is fixed. A portion of the fixed portion of the torsion bar that is opposite to the flat and parallel flat surfaces of the portion, and an inclined surface that is inclined toward the end of the fixed portion and expands with respect to each other. The combination of the inwardly facing surface of the branch portion constitutes the guide means of the block device of the torsion bar, and the block device is axially movable along the axis of symmetry of the valve spool.
And the power case described in 2. 4. The torsion bar blocking device comprises:
It is constituted by a die-shaped dowel, which is fixed to the end of a rod arranged coaxially to the pinion for free axial movement in the passage, said rod from the bottom of the bushing to the end of the pinion. The power case according to any one of claims 1 to 3, wherein the power case is extended and is projected beyond the steering casing so as to be associated with the control device of the block device. 5. A dice-shaped dowel constituting a block device is mounted between a branch portion of a fixed portion of a torsion bar and an inclined surface of a groove of a cylindrical portion of a valve spool, and the dowel has a fixed surface and Comprising a plurality of lateral flat parallel surfaces facing the surface of the branch of the complementary ramp, facing the conical ramp of the cylindrical end portion of the valve spool, the ramp of the dowel being The shape of the eye is such that it is arranged to engage with the inclined surface of the valve spool starting from the flat surface of the groove facing the flat surface of the fixed portion, and the shafts are opposed at the same distance with respect to the inclined surface of the fixed portion. 6. The power case according to claim 4, wherein the positioned end portion forms an angular clearance of the valve spool, thereby enabling hydraulic assistance. 6. The torsion bar blocking device comprises:
The power case according to claim 1, wherein the power case is mounted in a direction intersecting with the torsion bar and is connected to the control device via the bushing.