JPS6145579B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a power steering device using a planetary gear mechanism, in which the planetary gear mechanism has play related to vehicle speed, thereby improving steering stability especially during high-speed driving. This invention relates to improvements in steering devices.

Conventionally, many power steering devices of this type have been proposed by the present applicant (for example, Japanese Patent Application Laid-Open No. 100542/1982 and Japanese Utility Model Application No. 73636/1989).

However, with such conventional power steering devices, the steering force is light when driving at low to medium speeds, but on the other hand, when driving at high speeds, the ground friction force with the road surface is small, so even if the steering force is small, the steering force is small. Since the steering wheel easily turns, which can lead to an unexpected accident due to over-turning the steering wheel, a mechanism is usually provided to apply a steering reaction force.

In order to improve such steering stability, the present invention provides a power steering device that solves the problem of steering stability during high-speed driving by providing a planetary gear mechanism with play related to vehicle speed. It provides:

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In Fig. 1, 1 is a cylinder housing, 2 is a cylinder housing, and 2 is a cylinder housing.
3 is a differential mechanism housing, and 3 is an input shaft connected to a handle (not shown). 4 is a sector gear, which is connected to the pitman arm of the steering wheel (not shown), and finally the sector gear 4 rotates (output) in proportion to the rotation (input) of the input shaft 3, steering the steering wheel. do. A piston 5 that meshes with a sector gear 4 is disposed within the cylinder housing 1, and defines working chambers A and B on both sides. A cylindrical screw shaft 6 is threadedly engaged with the inner peripheral surface of the piston 5, and is connected to the input shaft 3 via a torsion bar 9 by pins 7 and 8.

A rotatable disk 1 serves as a planetary gear mechanism C.
Sun gears 11a and 11b are symmetrically carved on the peripheral surfaces of the input shaft 3 and screw shaft 6, respectively, and a plurality of planet gears 12a and 12b that mesh with the sun gears are attached symmetrically to both sides of the disk 10 using pins 13. be placed in a specific manner. Each of the planet gears 12a and 12b is similarly meshed with a rotatable ring gear 14a and a ring gear 14b,
One ring gear 14a is connected via a rod 15,
The other ring gear 14b is connected to the spool 16 of the control valve 17 shown in FIG.

As shown in FIG. 4, a V groove 19 is formed in a part of the outer peripheral surface of the ring gear 14b in the tooth width direction of the ring gear 14b. The tip of the movable iron core 21 provided eccentrically from the center of the movable iron core 20 is constantly engaged by the elastic force of the return spring 25.

The solenoid case 20 is screwed into a recess 22 formed in the differential mechanism housing 2 and fixed via a lock nut 23.

The movable iron core 21 moves up and down through a through hole 24 formed in the differential mechanism housing 2, and normally protrudes from the through hole 24 by the elastic force of a return spring 25 installed in the solenoid case 20, and is connected to the ring gear 14b.
It also engages with the V groove 19 of the solenoid case 20.
The solenoid coil 26 disposed on the inner circumferential wall of the solenoid coil 26 is energized during high-speed operation, so that the solenoid coil 26 is pulled up from the V-groove 19 by a predetermined stroke.

When the detected value of the vehicle speed sensor 28 of the control device 27 that detects the vehicle speed exceeds a certain value, the solenoid coil 26 is excited by the amplifying current from the power source 30 via the amplifying device 29, and the vehicle speed increases. When the voltage drops below a certain level, the current is cut off and becomes de-energized. In this embodiment, a movable iron core 21 is provided that operates when the vehicle speed exceeds a certain level, but it is possible to select one that operates in proportion to the vehicle speed or one that operates in stages. Next, as the spool 16 moves, the control valve 17 shown in FIG.
selectively supplying pressure fluid to the

Next, the effect will be explained.

As shown in FIG. 4, when the steering wheel is turned and the input shaft 3 is rotated in a low-medium speed driving state where the movable iron core 21 is tightly engaged with the V-groove 19 of the ring gear 14b, the input shaft 3 is rotated. Since the sector gear 4 connected to the sector gear 4 is in a fixed state due to ground resistance, the piston 5 and the screw shaft 6 that mesh with the sector gear 4 are stationary, while the sun gear 1
1b is also fixed like the ring gear 11b. Therefore, the sun gear 11 of the input shaft 3
Due to the rotation a, the planet gear 12a rotates on its own axis without revolving, causing the ring gear 14a to rotate and the spool 16 to move. The switched control valve 17 delivers pressurized fluid from the hydraulic pump to one of the working chambers A or B defined within the piston 5. At the same time, the rotational force (steering force) of the input shaft 3 is transmitted to the other screw shaft 6 while twisting the torsion bar 9, so that the sun gear 11b rotates at the same rotational speed as the sun gear 11a with a slight phase lag. start. (3rd
As shown in the figure, the projection of the torsion bar 9 abuts against the input shaft 3). Therefore, the planet gear 12a, which was only rotating on its axis, rotates and revolves in parallel, like the other planet gears 12b, and stops the ring gear 14a. In other words, the control valve 17 is maintained in the switched state and thereafter continues to supply pressure fluid into the working chamber until the input shaft 3 stops.

As the screw shaft 6 rotates, the piston 5 that is engaged with it moves by a pitch proportional amount, but this movement is performed smoothly by the pressure fluid supplied to the working chamber A or B, and the operator The sector gear 4 can be rotated with an extremely small amount of force, and the steered wheels can be turned. While the input shaft 3 is rotating, the piston 5 is moved by the working fluid by an amount proportional to this pitch and follows.

When the input shaft 3 is stopped, the sun gear 11a is also stopped, but the other sun gear 11
b rotates by an amount equivalent to the amount of twist applied to the torsion bar 9 and then stops. Since the planet gears 12a and 12b continue to rotate for a short time until they stop, the ring gear 14a, which has been stopped until now, rotates in the opposite direction and stops at the initial position. In other words, the ring gear 14a rotates by the amount of torsion of the torsion bar 9 applied when the input shaft 3 rotates, and the spool 16 also moves to the neutral position accordingly.

Next, move the movable iron core 2 into the V groove 19 of the ring gear 14b.
When the vehicle speed exceeds a certain speed from a low-medium speed driving state in which 1 is tightly engaged, an output signal is sent to the amplifier 29 from the vehicle speed sensor 28 of the control device 27 that detects this vehicle speed. As a result, the current from the power source 30 is amplified and energized to the solenoid coil 26. When the solenoid coil 26 is excited, a V-groove 19 of the ring gear 14b,
The movable core 21, which has been engaged by the elastic force of the return spring 25, is pulled up by a predetermined stroke as shown in FIG. When the movable iron core 21 is pulled up, play, that is, a gap X is generated between it and the V groove 19 of the ring gear 14b.

Therefore, when the steering wheel is turned in such a high-speed driving state, the ring gear 14b is in a state where it can rotate by the gap X formed between it and the movable iron core 21, and during this time, the first stage Since the ring gear 14a does not rotate due to the spring reaction force of a return spring (not shown) of the spool 16, the spool 16 does not move due to the rod 15 attached to the ring gear 14a.

Therefore, no pressure fluid is supplied to the working chambers A or B, so the steered wheels do not turn.

Then, when the steering wheel is further steered in a predetermined direction, the ring gear 14b is fixed while moving by the amount of play described above, so the ring gear 14a rotates as described above, and the ring gear 14
Spool 16 by rod 15 attached to a
moves in a predetermined direction, pressure fluid is supplied to one of the working chambers A and B, and the steered wheels are steered in a predetermined direction. Other operations are the same as those at low and medium speeds, so explanations will be omitted.

Next, in the device of this invention, when performing valve centering (input-pressure characteristics, right-turn and left-turn characteristics are symmetrical with respect to the neutral axis), the power steering device is Place it on the test, fix the sector shaft (not shown) and record the input and pressure rise characteristics. Based on this record, the lock nut 2 shown in Figure 4 is
3 is loosened and the solenoid case 20 is rotated to either the left or right. Due to the rotation of the movable core 21 eccentric to the solenoid case 20, the movable core 21 moves relatively within the V-groove 19 and moves through the V-groove 19. The ring gear 14b is rotated around its axis, and at the same time, the planet gears 12a, 12b meshing with the ring gear 14b are rotated to rotate the ring gear 14a, which has been rotatably installed from the beginning. Note that the rotation of the ring gear 14b is up to twice the eccentricity of the movable iron core 21, and therefore,
Adjustment can be made within that range.

When this centering is completed, the solenoid case 20 is fixed with the lock nut 23, and the eccentric movable iron core 2
1 functions as a fixing member and can perform its original operation.

In addition, in the embodiment of this invention, the ring gear 14b
A movable iron core 21 provided in the solenoid case 20 as a fixed part, and a V formed in the ring gear 14b.
However, as shown in FIG. 6, a pin 19b is installed in the ring gear 14b, and the movable iron core 2
It is also possible to form a V-groove 19c in 1a so as to engage each other.

As described above, the present invention engages a movable iron core that moves up and down according to the vehicle speed with a V groove formed in a ring gear, and by pulling up the movable iron core by a certain amount especially during high-speed driving, the movable iron core engages with a V groove formed in a ring gear. Since there is play, or a gap, in the engagement with the iron core, the steering force is not immediately transmitted to the steering wheels, which prevents accidents caused by over-turning the steering wheel and improves steering stability during high-speed driving. can be increased.

Further, since the movable iron core is provided at an eccentric position, valve centering can be easily performed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of the invention, and FIG. 2 is a
A vertical sectional side view taken along the - line in Fig. 1, and Fig. 3 are:
FIG. 4 is a partially enlarged sectional view taken along line - in FIG. 1, FIG. 5 is an explanatory diagram showing the operating state, and FIG. 6 shows another embodiment. FIG. 17... Control valve, 3... Input shaft, 6... Screw shaft, C... Planetary gear mechanism, 14b... Ring gear, 2... Differential mechanism housing, 19... V groove, 20... Solenoid Case, 21...Movable iron core, 27...Control device, 2
8... Vehicle speed sensor, 29... Multiplier, 30... Power supply.

Claims (1)

[Claims] 1. A power system in which the control valve that controls the pressure fluid supplied to the power cylinder is switched and controlled via a symmetrically interconnected planetary gear mechanism that is operated by the phase difference that occurs between the input shaft and the screw shaft. In the steering device, the control valve is linked to a ring gear of one planetary gear mechanism, and the ring gear of the other planetary gear mechanism is rotatable with respect to the differential mechanism housing;
A power steering device characterized in that a V-groove is formed in the ring gear, a movable core of a solenoid is opposed to the movable core of the solenoid so as to be engageable with the V-groove, and a control device is provided that excites the solenoid in accordance with vehicle speed.