KR950008767Y1 - Integral type power steering apparatus - Google Patents

Abstract

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Description

Integral Power Steering Device

1 is a longitudinal sectional view of an integral type power steering apparatus according to an embodiment of the present invention.

2 is a cross-sectional view of the main part on the left side, showing an operating state.

3 is a cross-sectional view of the main part on the right side, showing an operating state.

* Explanation of symbols for main parts of the drawings

2e: passage for communicating the gear chamber with the pressure chamber on the other side

2f, 24d: passage for communicating the supply passage from the gear chamber and the pump

4: cylinder 6: piston

8, 10: pressure chamber 12: rack

14: sector gear 15: gear chamber

36, 38: valve

The present invention relates to an integral type power steering device.

In general, the power steering apparatus introduces a pressure fluid switched and controlled by a control valve into pressure chambers formed on both sides of a piston inserted freely in a cylinder, and operates the piston by the pressure difference between both pressure chambers. It is supposed to give the aid of.

In such a power steering apparatus, a stroke limiter is provided for limiting the stroke of the piston by releasing the steering assist force after reaching the required steering angle so that excessive force is not applied to the steering linker. (Japanese special mission office 46-32090)

In the conventional power steering apparatus described above, a check valve is provided inside the piston to depressurize the high compression pressure chamber. In order to satisfy the function, the piston carries out carburization, and when a check valve or the like is incorporated, a machining step after the carburization is necessary.

Moreover, the stroke cannot be adjusted from the outside, and the restriction is large also at the position of the piston circumferential surface to which the check valve is attached.

Moreover, in the vehicle and the unnecessary vehicle which need the function of limiting the stroke of the piston, there are various drawbacks such as different parts constituting the power steering device and high management cost.

The present invention is made to eliminate the above-described drawbacks, and to provide a power steering apparatus that can limit the stroke of the piston without any change to the internal parts such as the piston.

The integral type power steering apparatus according to the present invention includes a piston inserted to move freely in a cylinder, a rack formed on an axial surface of the piston, a sector gear meshed with the rack, and a partition formed by an electric piston. Pressure chambers, electrical sector gears are accommodated, gear chambers communicating with one of the electrical pressure chambers, and the like, and the control valve is switched by steering wheel operation to pump two pressure chambers respectively. And communicating with and disconnecting from one of the tanks to supply pressure fluid to both pressure chambers, and furthermore, a passage for connecting the electric gear chamber to the other pressure chamber and a passage for supplying from the pump. And the like, a valve is attached to each of these passages, and one of the valves is opened by a predetermined rotation or more in both directions of the sector gear. It will have to.

In the integral power steering apparatus according to the present invention, since the valve is opened at one position of the rotation of the sector gear and the pressure chamber of the high pressure shaft of the cylinder is depressurized, excessive force is not applied to the link system after the sector shaft.

Next, the present invention will be described based on the embodiments shown in the drawings.

1 is a longitudinal sectional view showing an integral type power steering device according to an embodiment of the present invention, and is inserted in the cylinder portion 4 of the gear housing 2 so that the piston 6 can move freely. The cylinder 6 is partitioned into two pressure chambers 8 and 10 by the piston 6.

A rack 12 is formed on the side surface (lower in FIG. 1) of the piston 6, in which the sector gears 14 which interlock with the steering wheel (not shown) are engaged with each other. In addition, the piston 6 is rotated forward and backward according to the reciprocating motion. The space (gear chamber) 15 in which the sector gear 14 in the gear housing 2 is accommodated communicates with one pressure chamber 10 via the passage 2a.

A ball screw groove 18 is formed in the hole 16 of the shaft portion of the piston 6 described above, and the worm shaft 22 is formed through a plurality of balls 20 in the groove 18. It is fitted.

The valve housing 24 is fixed to one end of the above-mentioned gear housing 2, and the step shaft (input shaft) 26 is assembled so that the worm shaft 22 and the axis line which matched in the valve housing 24 match the axis line. Cylindrical holes are formed in the worm shaft 22 on the side opposite to the step shaft 26, and end portions of the step shaft 26 are fitted in the holes 22a, and both shafts 22 and 26 are formed. Is connected by a torsion bar 28 fitted in a hole formed in each shaft core.

In addition, the step shaft 26 is linked with a steering wheel (not shown).

In the valve housing 24 described above, a rotary control consisting of a valve rotor 30 connected to the pin 29 and rotating together with the step shaft 26 and a valve sleeve 32 formed on the worm shaft 22. The valve 34 is accommodated.

The control valve 34 is interposed between an oil pump (not shown) via a supply passage 24a and an inlet port 24b, and a reflux passage (not shown) and a pursuit port. And the pressure chamber 8 on the left side of the drawing via the passages 32a, 24c, and 2b, and the pressure chamber on the right side of the figure via the passage 32b. Each communicates with (10).

When the control valve 34 is switched by operation of the steering wheel, the pressure oil discharged from the oil pump is supplied to one of the pressure chambers 8 and 10, and at the same time, the pressure chamber on the other side is in communication with the tank. A pressure difference is generated between the pressure chambers of the pressure chambers, and the piston 6 is operated by this pressure difference to provide an auxiliary force in the steering direction.

On the wall surface of the aforementioned gear chamber 15, a pair of valves 36 and 38 are attached to the rotary end portions in the left and right directions of the sector gear 14 which rotates in accordance with the movement of the piston 6. . These valves 36 and 38 are cylindrical valve bodies 40 and 42 which are screwed into valve inserting holes 2c and 2b formed in the gear housing 2. ), Springs for pushing the springs 44, 46, springs 44 and 46, which are fitted to move freely in the valve bodies 40 and 42, inwardly of the gear chamber 15 It consists of (48), (50), etc.

The springs 44 and 46 protrude inwardly of the gear chamber 15 from stopper rings 52 and 54 fixed to the inner holes of the valve insertion holes 2c and 2d. When the pins 44a and 46a are inserted, and the sector gear 14 rotates to near the rotational limit point and presses the pins 44a and 46a, the springs 44 and 46 are springs 48. It moves beyond the elastic force of (50). The sides 44b and 46b of the pins 44a and 46a of the springs 44 and 46 have a small diameter, and the pins 44a and 46a. Introduction paths 44c and 46c are formed to pass through the inside of the springs 44 and 46 from the side surfaces of the springs 44 and 50.

Through-holes 40a, 42a and annular grooves 40b, 42b are formed in the wall surfaces of the cylindrical valve bodies 40, 42.

The annular groove 40b of the valve body 40 shown on the left side of the figure communicates with the pressure chamber 8 on the left side via a communication path 2e formed in the gear housing 2, and the valve body 42 on the right side. The annular groove 42b communicates with the inlet port 24b via the communication paths 2f and 24d. When the springs 44 and 46 are not operated, the through holes 40a and 42a of the valve bodies 40 and 46 are the large diameter portions of the springs 44 and 46. ), The small diameter portions 44b and 46b of the springs 44 and 46 move and open into the through holes 40a and 42a when operated. The pressure chamber 8 on the left side of the chamber 15 and the cylinder 4 or the gear chamber 15 and the inlet port 24b communicate with each other.

The operation of the integral type power steering apparatus according to the above configuration will be described. When the control valve is switched by the steering wheel, the hydraulic oil from the pump is supplied to one pressure chamber 8 (or 10) and the hydraulic oil in the other pressure chamber 10 (or (8)). Is returned to the tank, and the piston 6 is moved by the pressure difference between these pressure chambers 8 and 10 to rotate the sector gear 14. In the normal operation of power steering, the sector gear 14 is not rotated to a position in contact with the pins 44a and 46a at the tip of the springs 44 and 46 of both valves 36 and 38. In addition, since the hydraulic pressure acting on both ends of the springs 44 and 46 is the same on the left and right sides, the force for moving the springs 44 and 46 is not generated.

On the other hand, after the rotation angle of the tire reaches the limit point, especially when the driver excessively manipulates the steering wheel, for example, when turning to the left, the gear chamber 15 and the pressure chamber 10 in communication with it The pressure chamber 8 on the left side becomes low pressure and the piston 6 moves to the left side, and the sector gear 14 rotates counterclockwise, so that the piston 6 and the sector gear 14 come into contact with each other. The position shown by the virtual line (two dashed-dotted line) of 2 degrees is reached. As a result, the sector gear 14 presses the spring 44 of the left valve 36, so that the small diameter portion 44b of the spring 44 moves into the through hole 40a of the cylindrical valve body 40. Thus, the gear chamber 15 communicates with the left pressure relief 8, and the high pressure hydraulic fluid in the gear chamber 15 flows through the communication passage 2e to the pressure chamber 8 in the low pressure state.

Therefore, the gear chamber 15 and the pressure chamber 10 on the right side become low pressure, and no excessive sector shaft torque is required.

On the contrary, in the case of rotating to the right, the gear chamber 15 and the pressure chamber 10 on the right side are at low pressure and the pressure chamber 8 on the left is at high pressure, so that the piston 6 is moved to the right side, and the sector gear ( 14) rotates clockwise.

As described above, when excessive operation force is applied and the valve 38 on the right side is operated (see FIG. 3), the inlet port 24b communicates with the gear chamber 15, and the high pressure hydraulic oil from the pump is connected to the communication path ( 24d) flows into the gear chamber 15 via 2f, and the working oil in the pressure chamber 10 is returned to the tank.

In addition, adjustment of the rotation angle of a tire can be performed by adjusting the depth which inserts a valve assembly in valve insertion hole 2c (2d).

As described above, according to the present invention, it is possible to protect the link system after the sector axis by limiting the output of the power steering by reducing the high pressure state of the pressure chamber in the cylinder at the limit where the sector gear is engaged with the rack.

Claims (1)

By a piston 6 fitted to move freely in the cylinder, a rack 12 formed on the side of the piston 6, a sector gear 14 meshing with the rack 12, and an electric piston 6 Two pressure chambers (8), (10) and electrical sector gears (14), which are divided and formed in the cylinder (4), are accommodated and communicate with one of the pressure chambers (8) and (10). ), The control valve 34 is switched by operation of the steering wheel, and the two pressure chambers 8 and 10 are communicated to and disconnected from any one of the pump and the tank, respectively. In the integral type power steering apparatus for rapidly supplying pressure fluid to the pressure fluid at (10) and (10), a passage is formed in which the gear chamber (15) communicated with the other pressure chamber and a passage in communication with a supply path from the pump, Valves are provided in each of these passages, and a predetermined rotation or more in both directions of the sector gears 14 Side of the Integral-type power steering device, characterized in that the valve is to be opened.