JPH0438266A - Automatic steering system for vehicle - Google Patents

Abstract

PURPOSE:To prevent a burden of steering operation by a driver from increasing by releasing the connection between an automatic steering drive mechanism and an input shaft through a safety mechanism at a time when something goes wrong with an automatic steering control system and thereby such a reaction as more than the specified one has occurred in an interval between the automatic steering drive mechanism and the input shaft of a power steering mechanism. CONSTITUTION:When something goes wrong with an automatic steering control part, a servomotor 30 fails to generate driving force utterly and thereby it has become free of rotation, this trouble is inferred and if a handwheel is rotated for operation, an upper steering shaft 13b is rotated as well, and this rotation is transmitted to the upper end of an inner spool 18g via pins 18i1, 18i2. With this, a hydraulic mechanism works likewise in the case where a sleeve 31 is rotated by the servomotor 30, thus steerage by a driver is being assisted. On the other hand, when the servomotor 30 is subjected to seizure or binding at time of trouble, if a handwheel 14 is rotated for operation, some reaction occurs in space between the upper steering shaft 13b and the sleeve 31, and these pins 18i1, 18i2 separate from recess parts 31a1, 31a2, whereby the driver is released from the seizure of the servomotor 30, thereby enabling him to handle a steering wheel.

Description

[Detailed description of the invention]

■Industrial Application Fields The present invention relates to an automatic steering system for vehicles in which the input shaft of a steering mechanism is rotated by an automatic steering drive mechanism under the control of an automatic steering control means to automatically steer a vehicle. Regarding equipment.

[Prior art]

Conventionally, as this type of device, Utility Model Application No. 60-115174
The one disclosed in the above publication is known. According to this device, a rotating shaft of a servo motor connected to an automatic steering controller and a steering shaft are connected via a transmission mechanism made of gears.

[Problem to be solved by the invention]

However, with the conventional device described above, when an abnormality occurs in the automatic steering control system and the driver tries to steer in the correct direction and the direction of the wings, or when the driver does not steer when it should, the driver It is necessary to overcome the servo motor to operate the steering wheel, which requires a large steering force, resulting in poor operability. The present invention has been made to address the above problems, and
An automatic steering system for a vehicle that can disconnect the automatic steering control system when an abnormality occurs in the automatic steering control system, thereby preventing an increase in the burden of steering operations on the driver even in the event of an abnormality. The purpose is to provide equipment.

[Means to solve the problem]

In order to achieve the above object, the structural features of the present invention are as follows:
The steering link mechanism operates in response to the rotational steering input input to the input shaft connected to the steering wheel, and controls the supply and discharge of pressure oil discharged from the hydraulic pump to the power cylinder installed in the steering link mechanism. a power steering mechanism that drives the mechanism;
A vehicle automatic comprising: an automatic steering drive mechanism that is connected to the input shaft of the power steering mechanism via a transmission mechanism and rotates the input shaft by a required amount under control of an automatic steering control means. In the steering device, when a reaction force greater than a predetermined value is generated between the automatic steering drive mechanism and the input shaft of the power steering mechanism, the transmission mechanism is connected to the automatic steering drive mechanism and the input shaft of the power steering mechanism. The reason for this is that it is constructed so that it is equipped with a safety mechanism to release the connection.

[Operation and effects of the invention]

In the present invention configured as described above, under normal conditions, the automatic steering drive mechanism and the input shaft of the power steering mechanism are connected by the transmission mechanism, and the automatic steering control means can control the input shaft. The input shaft is rotated by the required amount to drive the steering link mechanism, but if a failure occurs in the automatic steering control system and the driver applies a rotational steering input from the steering wheel, the automatic steering A reaction force greater than a predetermined value is generated between the automatic steering drive mechanism and the input shaft of the power steering mechanism, and the safety mechanism releases the connection between the automatic steering drive mechanism and the input shaft. Therefore, when the driver determines that an abnormality has occurred in the automatic steering control system and attempts to rotate the steering wheel to drive the input shaft of the power steering mechanism, the automatic steering drive mechanism and the power steering A reaction force greater than a predetermined value is generated between the input shaft of the steering mechanism, the safety mechanism releases the connection between the automatic steering drive mechanism and the input shaft, and the automatic steering control system is subsequently disconnected. This can prevent an increase in the burden of steering operations on the driver.

【Example】

Hereinafter, one embodiment of the present invention will be explained using the drawings. Fig. 2 schematically shows the entire front wheel steering mechanism in which the vehicle automatic steering device according to the present invention is applied to a vehicle equipped with a steering mechanism on the front wheels. It is shown in This front wheel steering mechanism is displaced in the axial direction to rotate the left and right front wheels FWI,
It has a rack par 11 for steering the FW 2. The rack par 11 is connected to the steering handle 14 via a pinion gear 12, a lower steering shaft 13a, and an upper steering shaft 13t, and has rack ends 15a and 15b fixed to both ends thereof.
Left and right tie rods 16a, 16b swingably connected to
The left and right front wheels F are connected via left and right knuckle arms 17a and 17b rotatably connected to the same tie lofts 16a and 16b.
WI and FW2 are connected. Between the lower steering shaft 1811 and the upper steering shaft 1.3b, there is a control valve 18 consisting of a four-way valve shown enlarged in Fig. 1.
is assembled. The control valve 18 has an outer sleeve 18f, an inner spool 18g, and a tone run part 13b3 configured at the lower end of the upper steering shaft arranged concentrically in a case 18e that also serves as a gear box, and
The lower end of the Toshi sun/a part 13b3 is connected to the lower steering shaft 13a.
The outer sleeve 18f is connected to the lower steering shaft 13a by a pin 101, and the outer sleeve 18f is engaged with the lower steering shaft 13a by a pin 102. The hydraulic oil supplied through the boat 18at is supplied from the boat 18b (or boat 18C) to the right oil chamber 22a (or left oil chamber 22b) of the power cylinder 22, and the hydraulic oil is supplied to the left oil chamber 22b (or right oil chamber 22b) of the power cylinder 22. Hydraulic oil from the oil chamber 22a) is introduced from the boat 18C (or port 1-18b) and discharged from the boat 18d to the reservoir 23 via the conduit P2. The outer sleeve 18f of the control valve 18 is connected to the lower steering shaft 1.
The inner spool 18g is engaged with a sleeve 31 that is press-fitted into the drive section 30a of the servo motor 30 via a transmission mechanism 19 provided at the upper end of the control valve 18. . Note that when the inner spool 18g rotates in the direction of the arrow in FIG. 1 and its relative angle with the outer sleeve 18f shifts, the ports 18a and 18b communicate with each other, and the ports 18d and 18c communicate with each other. The inner spool 18g rotates in the direction opposite to the arrow direction in Figure 1, and the outer sleeve 18f
When the relative angle between port 18a and port 18 is shifted,
port 18d and port 18b communicate with each other.
The two are connected. In the transmission mechanism 19, as shown enlarged in FIG. 3, the shaft portion 13bl of the upper steering shaft 13b is rotatably inserted inside the upper end of the cylindrical inner spool 18g. However, two holes 18g1 and 18g2 are provided on the upper side of the inner spool 18g, and the company's 18g
1. Bin 18i1. in 18g2. 1812 is press-fitted and the bottle 1 protrudes from the inner surface of the inner spool 18g.
The tip of 811.1812 is the shaft portion 13 of the upper steering shaft 13b.
The inner spool 18g and the upper steering shaft 13b are not actually engaged with each other because they are fitted with a gap into the through hole 13b2 provided to communicate with the bl side surface. A through hole 31a is provided in the sleeve 31 to which the upper end of the inner spool 18g is connected, and the through hole 31a has a cylindrical upper part and a deformed cylindrical lower part as shown in FIG. The upper end of the inner spool 182g passes through the inner spool 182g rotatably. However, in this case as well, the rear ends of the bottles 1811 and 1812 press-fitted into the inner spool 18g are recessed portions 31 a 1. 31a2, so normally the inner spool 18g and sleeve 3
1 rotates synchronously. The servo motor 30 into which the sleeve 31 is press-fitted is fixed to the vehicle body through an outer case, and drives the sleeve 31 in the forward and reverse directions by a predetermined amount via the drive unit 30a in response to a control signal output from the automatic steering control unit 32. rotate it in the direction. The automatic steering control unit 32 outputs a control signal to the servo motor 30 according to a predetermined control mode, and controls the steering according to a predetermined program or steers the vehicle so as to track the vehicle in front. or steering control according to instructions from a signal generator installed within the road surface. The bower cylinder 22 to which hydraulic oil is supplied and discharged by the control valve 18 responds to the supply and discharge of the hydraulic oil. 11 in the axial direction, and assists the driver in steering the left and right front wheels FWI, FW by the steering wheel 14 or by the servo motor 30 controlled by the automatic steering control section 32. Note that a switching valve 24 is provided between conduits P1 and P2 in the hydraulic drive system, and the switching valve 24 is normally closed to block the conduits PI and P2 and assist front wheel steering using hydraulic pressure. When there is an abnormality in the hydraulic drive system, the hydraulic pump 2 is opened to allow communication between the conduits PI and P2.
To prevent excessive load from being applied to 1. Next, the operation of the above embodiment will be explained. It is assumed that the driver is currently turning on an automatic steering control switch (not shown). Assume that the automatic steering control unit 32 determines that it is necessary to steer the vehicle to the right according to a predetermined control mode. Then, the automatic steering control section 32 outputs a control signal to the servo motor 30 to rotate the sleeve 31 in the direction of the arrow in FIG. When the sleeve 31 rotates, the positions of the recesses 31al and 31112 provided in the inner wall of the sleeve also rotate, so that the bins 1811.
At the rear end of 1812 there is a force that tries to rotate it in the same direction and the same pin 1811. A force acts to push 1812 toward the center of the rotating shaft. Since the bottles 1811 and 1812 are press-fitted into the holes 18g+, 18g2 provided in the inner spool 18g, they will not move toward the center of the rotating shaft unless a predetermined force is applied. Provided recess 31 a 1. When the position of 31a2 rotates, the same pin 1811.18+2 also rotates. Same pin 1811. With the rotational movement of 1812, the same pin 1
811. Inner spool 1 where 1812 is press-fitted
Since the upper end of 8g also rotates in the direction of the arrow in FIG. 18c. Therefore, the high pressure hydraulic oil supplied from the hydraulic pump 21 passes from the port 18a to the port 18b to the power cylinder 2.
Power cylinder 2 is supplied to the right oil chamber 22m of power cylinder 2.
The piston 22c in the power cylinder 2 is moved to the left in FIG.
It is discharged to 8. Piston 22 in power cylinder 22
When C moves to the left, the left and right front wheels FWI
, FW2 is steered to the right, so the servo motor 30
This means that the steering is assisted by the hydraulic mechanism. Further, as the power cylinder 22 moves, the pinion 12 is rotated in the same direction as the inner spool 18g in FIG. 1. As the lower steering shaft 13a fixed to the lower steering shaft 13a also rotates due to the rotation of the pinion 12, the outer sleeve 18f engaged with the lower steering shaft 13a by a pin also rotates by a predetermined amount.
The hydraulic mechanism assists steering until the rotation of f catches up to the rotation of the inner spool 18g (until there is no relative angle difference). Meanwhile, the automatic steering control unit 32 Assume that it is determined that it is necessary to steer the vehicle to the left.The automatic steering control unit 32 outputs a control signal to the servo motor 30 to rotate the sleeve 31 in the direction opposite to the arrow direction in FIG. When rotates in the direction opposite to the direction of the arrow in Fig. 1, the inner spool 1
The upper end of 8g rotates in the direction opposite to the arrow direction shown in FIG. 1, so that ports 18a and 18c communicate with each other, and ports 18d and 18b communicate with each other. Therefore, the high pressure hydraulic oil supplied from the hydraulic pump 21 is supplied to the power cylinder 2 from the port 18a via the port f8c.
Since the oil is supplied to the left oil chamber 22b of power cylinder 2,
The piston 22c in the power cylinder 22 is moved to the right in FIG. Piston 2 in power cylinder 22
When 2C moves to the right, tie rods 16a and 16b
and the left and right front wheels FW via the knuckle arms 17a and 17b.
Since I and FW2 are steered to the left, in this case as well, the steering by the servo motor 30 is assisted by the hydraulic mechanism until the rotation of the outer sleeve 18f catches up with the rotation of the inner spool 18g. On the other hand, assume that some abnormality has occurred in the automatic steering control section 32. Assume that due to this abnormality, the servo motor 30 no longer generates a full driving force and is now able to rotate freely. When the driver detects the abnormality and rotates the steering wheel 14, the upper steering shaft 13t) rotates in accordance with the operation. The shaft portion 13b1 of the upper steering shaft 13b is inserted into the upper end of the cylindrical inner spool 18g. Through hole 13b provided in lower end 13b1 of the upper steering shaft 1, 3b
Inner spool 18g upper hole 18g for 2
．． Bottle 1811. press-fitted into 18 g 2. 181
When the tips of the inner spool 18g are engaged, the rotation of the upper steering shaft 13b is transmitted to the upper end of the inner spool 18g. As a result, the hydraulic mechanism operates in the same manner as when the sleeve 31 is rotated by the servo motor 30, and the steering by the driver is assisted. On the other hand, suppose that if some abnormality occurs in the automatic steering control section 32, the servo motor 30 becomes stuck and does not move at all. When the driver detects an abnormality and attempts to rotate the handle 14, the bin 1 is rotated as the upper steering shaft 13b rotates.
811. 1812 also tries to rotate. but,
Bin 1811. The rear end of 1812 is engaged with recesses 31a1 and 31a2 provided in the inner wall of the sleeve 31 (
4), since the sleeve 31 is fixed to the fixed motor 30, the upper steering shaft 11b and the sleeve 31
A reaction force is generated between the bottles 1811. The rear end of 18i2 forms a concave portion 31 m1 as it rotates. 31a
2 generates a force pushing toward the center of the rotation axis. Bottle 1811.1812 has hole 18g1. provided in inner spool 18g. 18g2 is press-fitted and fixed, so the fixing force is not very large, and as the force pushing the bins 1811 and 1812 toward the center of the rotational axis increases as they rotate, the bins 1811 and 1812 are pressed into place and fixed. 1812 starts moving in the same direction. As the rotation moves further, bin 1
811. L812 is the recess 3 L a L, 31 a
2, and gradually moves into the through hole 13b2 while slidingly contacting the inner wall of the deformed cylindrical shape (see FIG. 6). At this time, since the inner wall of the deformed cylindrical shape is shaped so that the distance to the center of the upper steering shaft 13b gradually approaches,
The bins 1811 and 1812 move little by little toward the center of the rotation axis. Then, when the upper steering shaft 13b rotates 90'', the rear end of the bin 1811, 1812 is completely inserted into the hole 18 provided in the inner spool 18g, as shown in FIG.
g1. 18g2, even if it rotates further, the rear end will not even come into sliding contact with the sleeve 31, and the driver can perform the nodle operation freed from the fixation of the servo motor 30. Note that when the driver wishes to perform steering using the steering wheel 14 without relying on the automatic steering control, or when an abnormality occurs in the automatic steering control system, the switching valve 24 can be turned off using a switch (not shown). It is activated to connect the conduits P1 and P2, and the hydraulic power steering mechanism is not activated. In the above embodiment, the safety mechanism is such that the bottle enters the through hole in the upper steering shaft, but it may also be configured so that the bottle breaks when a force exceeding a predetermined level is applied. can. Needless to say, make sure that the broken bottle does not get caught. Furthermore, in the above-described embodiment, when the bottle is housed in the through-hole, it does not return to its original position, but a spring may be provided in the through-hole to press it against the inner wall of the sleeve. You can also do it. In this case, automatic steering control can be continued if the abnormality in the automatic steering control system is recovered. In addition, as a safety mechanism, it is also possible to use a structure in which the pawl in a well-known dog clutch is replaced with a bottle as in this embodiment.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of the automatic steering system for a vehicle according to the present invention, Fig. 2 is a schematic configuration diagram of a front wheel steering mechanism to which the automatic steering system for a vehicle according to the present invention is applied, and Fig. 3 is a safety Sectional views of the mechanism, FIGS. 4 to 6 are cross-sectional views showing the operating state of the safety mechanism. Explanation of symbols 11...Rubkuba-12...Pinion, 13a, 1
3b... Steering shaft, 13b2... Through hole, 14...
Handle, 16a, 16b... tie rod, 17a
, 17b...knuckle arm, 18g...inner spool, 18g1. 18g2...hole, 1811
．． 18i2...Bin, 21...Hydraulic pump, 22
...Power cylinder, 30...Servo motor, 31
... Sleeve, 31 a 1 ° 31 a 2 ... Concave portion, 32 ... Automatic steering control section.

Claims (1)

[Claims] Controls the supply and discharge of pressurized oil discharged from a hydraulic pump to a power cylinder provided in a steering link mechanism that operates in response to a rotational steering input input to an input shaft connected to a steering wheel. a power steering mechanism that drives the steering link mechanism;
an automatic steering drive mechanism that is connected to the input shaft of the power steering mechanism via a transmission mechanism and rotates the input shaft by a required amount under control of an automatic steering control means; In the steering device, the transmission mechanism is configured to transmit the automatic steering drive mechanism and the input shaft when a reaction force greater than a predetermined value is generated between the automatic steering drive mechanism and the input shaft of the power steering mechanism. An automatic steering system for a vehicle, characterized in that the automatic steering system is configured to include a safety mechanism for releasing the connection with the vehicle.