JPS6137574Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a power steering device, and its purpose is to communicate the two chambers of the power cylinder to make the steering performance moderately heavy during straight travel and slight steering. The object of the present invention is to eliminate the uneasiness that the steering wheel feels light especially when driving at high speeds, and to improve the restorability of the steering wheel.

In general, automobiles equipped with a power steering system have problems in that the steering wheel is rather light when driving at high speeds, creating a feeling of uneasiness, and that the steering wheel has poor restorability during small steering operations.

The present invention was developed to solve the above-mentioned conventional problems. Focusing on the fact that when driving at high speeds, the vehicle is driven exclusively in a straight line or in a slightly steered state, one side of the power cylinder is operated only near the neutral position of the piston. A bypass path is formed to communicate a groove communicating with the chamber and a passage communicating with the other chamber of the power cylinder, and an embodiment thereof will be described below with reference to the drawings.

In FIG. 1, reference numeral 10 indicates a power cylinder of the power steering device. A valve housing 11 is fixed to one end of the power cylinder 10, and a servo valve that controls the supply and discharge of pressure oil to the power cylinder 10 is attached to the valve housing 11. A device 12 is housed therein. A piston 13 is slidably fitted into the power cylinder 10, and the piston 13 divides the power cylinder 10 into a left chamber 10a and a right chamber 10b. A rack 14 is carved on the outer periphery of the piston 13, and a sector gear 16 carved on a cross shaft 15 is meshed with this rack 14. The crossshaft 15 is connected to the steering wheels via the required steering linkage.

The servo valve device 12 includes a main valve member 17 fitted in the valve housing 11, and a first flap valve 18 and a second flap rotatably housed in valve chambers formed at both ends of the main valve member 17. It consists of a valve 19. A steering shaft 20 is integrally connected to the first and second flapper valves 18 and 19.
is connected to the handle. A screw shaft 21 is integrally engaged with one end of the main valve member 17.
1 is inserted into the power cylinder 10 and is screwed into the piston 13 via a ball 22. The screw shaft 21 is flexibly connected to the steering shaft 20 via a torsion bar 23.

In addition, 25 and 26 in the figure are the valve housing 11.
2 shows the pressure oil supply port and discharge port provided in
Reference numerals 7 and 28 indicate pressure oil passages formed in the power cylinder 10 and the valve housing 11, respectively. The passage 27 is the left chamber 10a of the power cylinder 10.
The passage 28 is opened to the right chamber 10b of the power cylinder 10, and the pressure oil supplied from the supply port 25 is distributed to one of the passages 27 and 28 by actuation of the servo valve device 12 by operating the handle. The other end is connected to the discharge port 26.

A bypass passage 30 having a throttling effect is formed in the power cylinder 10 and communicates with the passage 27, and this bypass passage 30 is opened on the inner circumferential surface of the power cylinder 10 into which the piston 13 is fitted. An annular V-groove 31 is formed on the outer periphery of the piston 13, and this V-groove 31 connects to the right chamber 1 of the power cylinder 10 through a communication passage 32 formed in the piston 13.
It is connected to 0b. The bypass passage 30 communicates with the V groove 31 near the neutral position of the piston 13, thereby allowing the left chamber 10a and the right chamber 10b of the power cylinder 10 to communicate with each other. When slid, the bypass passage 30 is closed by the outer peripheral surface of the piston 13, and communication between the left chamber 10a and the right chamber 10b of the power cylinder 10 is cut off.

Since the device of the present invention is configured as described above, when the piston 13 of the power cylinder 10 is located at or near the neutral position, that is, when the vehicle is traveling straight or when performing small angle steering, the power cylinder 10 is Left and right chambers 10a, 10
b are communicated with each other via the passage 25, the bypass passage 30, the V-groove 31, and the communication passage 32, so that the power steering action is reduced. Therefore, it is possible to eliminate the anxiety caused by the steering wheel becoming too light especially when driving at high speeds, and it is also possible to improve the restorability of the steering wheel during minute steering.

However, when the handle is turned significantly, the stroke of the piston 13 also becomes large, and the bypass passage 30 is blocked by the outer peripheral surface of the piston 13, causing the left and right chambers 10 of the power cylinder 10 to close.
Since the communication between a and 10b is cut off, nimble steering performance is ensured by normal power steering action.

FIG. 2 shows another embodiment of the present invention, in which the power cylinder 1
A hole 33 communicating with the passage 27 is formed in the hole 33, and a plunger 34 that projects into the power cylinder 10 is slidably inserted into the hole 33. On the other hand, an annular cam groove 35 is formed on the outer periphery of the piston 13.
This cam groove 35 is connected to the right chamber 10 of the power cylinder 10.
It is connected to b. The plunger 34 is joined to the cam groove 35 of the piston 13 by the force of the spring 36, and when the piston 13 is slid from the neutral position in the left-right direction, the plunger 34 moves along the cam groove 35 against the spring 36. is displaced in the direction of The plunger 34 is formed with a bypass passage 37 having a throttling effect that communicates with and blocks the passage 27, and this bypass passage 37 communicates with the cam groove 35.

Therefore, when the vehicle is traveling straight or when performing slight steering, the left and right chambers 10a, 10 of the power cylinder 10 are
b communicate with each other via the passage 27, a bypass path 37 formed in the plunger 34, and a cam groove 35. However, when the steering wheel is turned with a large force, the plunger 34 moves along the cam groove 35 as the piston 13 slides. Since the bypass passage 37 and the passage 27 are displaced and the communication between the bypass passage 37 and the passage 27 is cut off, the communication relationship between the power cylinder left and right chambers 10a and 10b is also cut off, thereby achieving the same effect as in the embodiment described above.

As mentioned above, the present invention has a configuration in which both chambers of the power cylinder communicate with each other via a bypass path when driving straight and during slight steering, which eliminates the feeling of anxiety that the steering wheel is light when driving at high speeds. It also has the feature of improving the resilience of the handle. Particularly, since the present invention is configured to open and close the bypass passage that communicates the two chambers of the power cylinder by using the movement of the piston, it has the advantage of being extremely simple in configuration.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a power steering device showing an embodiment of the present invention, and FIG. 2 is a sectional view of the same showing another embodiment of the invention. 10... Power cylinder, 12... Servo valve device, 13... Piston, 27, 28... Passage, 3
0,37...bypass road, 31,35...groove.

Claims (1)

[Scope of utility model registration request] In a power steering device equipped with a power cylinder controlled by the operation of a servo valve device based on handle operation, a groove communicating with one chamber of the power cylinder is provided on the outer periphery of the piston of the power cylinder, and a groove is provided in the outer periphery of the piston of the power cylinder, and the neutral a bypass path that communicates the groove with a passage communicating with the other chamber of the power cylinder near the position, and blocks communication between the groove and the passage when the piston is slid beyond the vicinity of the neutral position; A power steering device that is provided on the power cylinder side.