JPS63145173A - Integral power steering device - Google Patents

Abstract

PURPOSE:To improve the safety during traveling by allowing a spring chamber set close at both both edges of a spool to communicate to a tank through a variable throttle whose opening degree is adjusted according to the car speed and forming a steering reaction force chamber by allowing the upstream side of the variable throttle to communicate to an actuator. CONSTITUTION:Rands 55 and recessed grooves 56 are formed alternately on the outer periphery of a spool SP, and are inclined by an angle theta with respect to the tangential line crossing at right angles in the direction of axis of the spool SP. Projecting parts 57 and recessed parts 58 are formed alternately on the inner periphery of the spool SL, and are inclined by an angle alpha similarly in case of the rands 52 and recessed grooves 56. Spring chambers 59 and 60 are formed at the both edges of the spool SP, and passages 63 and 64 are connected to the spring chambers 59 and 60, respectively. Variable throttles 65 and 66 are installed into the passages 63 and 64, and a spring chamber communicates to a tank through the variable throttles 65 and 66. The variable throttle valve is controlled by a controller.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an integral power steering device using a rotary valve.

(Prior Art) The conventional integral power steering system shown in FIGS. 5 to 9 includes a cylinder housing H1 and a valve housing H2 in which a rotary valve is installed.

The piston l housed in the cylinder housing H1 has a through hole 3 having a threaded groove 2 on its inner periphery, and the tip of the hole 3 is closed with a cap 4. A rack 5 is formed on the outer periphery of the piston 1, and a sector gear 6 is engaged with the rack 5.

A hollow worm shaft 8 having a thread groove 7 formed on its outer periphery is inserted into the through hole 3, and a pawl 9 is interposed between the thread groove 7 and the thread groove 2 of the through hole 3. Therefore, when the piston l moves, the worm shaft 8 rotates.

The base end of the worm shaft 8 is rotatably supported by a bearing (not shown) provided in the valve housing H2.

A stub shaft 10 is inserted into the valve housing H2, and the stub shaft 10 is rotatably supported by a pawl bearing 11.

A torsion bar 12 is inserted into the worm shaft 8, and its tip is fixed with a pin 13a. The other end of this torsion bar 12 is inserted into the insertion hole 14 of the stub shaft 10, and the insertion end is fixed with a pin 13b.

The spool SP is attached to the stub shaft 10 as described above.
A groove 18 is formed in the axial direction in the fitting portion of the spool SP, and the pin 15 fixed to the stub shaft IO is inserted into this groove 16. Therefore, the spool SP becomes a sliding eye in the axial direction while rotating integrally with the stub shaft lO.

Further, a sleeve SL is fitted around the outer periphery of the spool SP, and this sleeve SL rotates integrally with the worm shaft 8 and is rotatable relative to the spool SP.

As is clear from FIG. 8.9, the spool SP constructed as described above has lands 17 to 22 and grooves 23 to 28 alternately formed therein, and the lands and grooves are also formed in the sleeve SL. Convex portions 28 to 34 and concave portions 35 to 40 corresponding to
and is formed.

Among the lands of the spool SP, lands 1B and 2 are located every other land in the circumferential direction of the spool SP.
Tank boats 41 to 43 are formed in each of the valve housings 41 to 43, and these tank boats 41 to 43 communicate with the tank T via a drain chamber 44 formed in the valve housing H2.

Furthermore, the land 1 in the circumferential direction of the spool SP
As is clear from FIG. 8, the widths of the recesses 7 to 22 are slightly smaller than the circumferential widths of the recesses 35 to 40 of the sleeve SL. Further, the circumferential width of the convex portions 28 to 34 of the sleeve SL is also made smaller than the circumferential width of the grooves 23 to 28 of the spool SP.

Therefore, when the spool SL is held at the neutral position in FIG. 8, the grooves 23 to 28 of the spool SP and the sleeve S
All four parts 35-40 of L communicate with each other, and it also communicates with tank T via tank boats 41-43 and a drain chamber 44.

Further, first to third annular grooves 45 to 47 are formed on the inner circumference of the valve housing H2 that contacts the outer circumference of the sleeve SL.

As is clear from FIG. 8.9, the first annular grooves 45 are always in communication with the pump P and are located every other part in the circumferential direction of the sleeve SL. It communicates with each of the recesses 36, 38, and 40.

The second annular groove 46 passes through one pressure chamber 48 defined by the piston l, and the recess 36.38.
．． It communicates with the surfaces of the convex portions 30, 32, and 34 adjacent to the protrusion 40, and functions as one of the 7 cutout ports.

Further, the third annular groove communicates with the other pressure chamber 48 on the opposite side from the pressure chamber 4, and also communicates with the convex portion 30.3.
2.34 is connected to the surface of another convex portion 28.31.33, and functions as the other actuator boat.

Therefore, when the spool SP is rotated clockwise from the state shown in FIG. 8, for example, as shown in FIG. The groove 24 communicates with the recess 3B, the groove 2B communicates with the recess 38, and the groove 28 communicates with the recess 40, respectively. Further, the third annular groove 47 includes the groove 23 and the groove 35, the groove 25 and the groove 37,
It communicates with the pump boats 41 to 43 via the groove 27 and the recess 39, respectively.

Then, if the spool SP is switched to the left, the first annular groove 45 and the third annular groove 47 will communicate with each other, and the second annular groove 4B will communicate with the tank boats 41 to 43.

As described above, the flow direction of one hydraulic fluid is controlled by switching the spool SP to the left or right, but the turning angle θ of this spool SP is determined by the stub shaft 10 as shown in FIG.
Stopper lOa and worm shaft 8 provided integrally with
It is regulated by the hollow part of.

Therefore, when the handle (not shown) is held in the neutral position, the first to third annular grooves 45 to
All 47 are tank boats 41-43 and drain room 4
4 to the tank T, and no pressure acts on the pressure chambers 48 and 49. Therefore, the piston l maintains the illustrated position, the steering angle becomes zero, and the vehicle continues to travel straight.

If you turn the handle to the left or right from the above neutral state,
As a result, the stub shaft 10 rotates, but the worm shaft 8 does not rotate due to the turning resistance on the wheel side.In other words, at the initial stage when the steering wheel is turned, only the stub shaft 10 rotates even though the torsion bar 12 is twisted. do.

If the handle is now turned to the right, the stub shaft 10 will rotate as described above, and the spool SP will also rotate to the right. If the spool SP turns clockwise in this way, the 4th first annular groove 45 and the second
The third annular groove 47 communicates with the annular groove 46, and the third annular groove 47 communicates with the tank T.
A, the oil discharged from the pump P is supplied to one pressure chamber 48, and the hydraulic oil in the other pressure chamber 49 is returned to the tank T. Therefore, the piston 1 moves to the left in the drawing, rotates the sector gear 6, and steers the wheels to the right.

When the piston 1 moves as described above, the worm shaft 8 also rotates accordingly.

The spool SP and the sleeve SL rotate integrally while maintaining their relative rotation angles.

When the handle l is stopped from this state, the spool SP also stops, but the sleeve SL blocks communication between the first annular groove 45, the second annular groove 46, the third annular groove 47, and the tank boat. The wheel rotates a little to the desired position and then stops. Therefore, when the steering wheel is stopped, the pressure chambers 48 and 49 are locked, and the wheel remains at the steered position.

Note that when the steering wheel is turned to the left, the principle is exactly the same as when the steering wheel is turned to the right, except that the rotation directions of the spool SP and the sleeve SL are different.

(Problem that the tree design aims to solve) Regarding the power steering system, increasing the power assist force when the vehicle is running at low speeds and reducing it when driving at high speeds is the most safe and easy to operate system. Feeling will also improve.

However, the conventional integral power steering system described above is not configured to control the power assist force according to the vehicle speed. The reason for this is considered to be that even if an attempt is made to provide a reaction force mechanism while the spool SP and sleeve SL rotate relative to each other, the configuration thereof becomes complicated. For this reason, the idea that an integral power steering system cannot be provided with a mechanism for controlling the reaction force of the steering has been established as a general concept.

The purpose of this invention is to provide a steering reaction force mechanism to an integral power steering device, which has been considered impossible in the past.
The goal is to improve the safety of the vehicle.

(Means for Solving the Problems) In order to achieve the above object, the present invention makes the sleeve and the spool relatively movable in the axial direction, and the above-mentioned four parts and grooves formed on the sleeve and the spool. Both or one of the sleeves and the spool are inclined with respect to a tangent perpendicular to the axial direction of the spool, and the spring chamber facing both ends of the spool is provided with a variable throttle that adjusts the throttle opening according to the vehicle speed. The upstream side of the variable throttle is communicated with the passage leading to the actuator.

(Operation of the present invention) With the above structure, by relatively moving the spool and the sleeve in the axial direction, the amount of overlap between the groove and the recess can be changed.

Therefore, by controlling the pressure in the spring chamber facing both ends of the spool, it is possible to change the amount of overlap between the groove and the recess. This spring chamber is communicated with the tank via a variable throttle that changes its opening depending on the vehicle speed, and the actuator hoard is communicated upstream of this variable throttle, so the pressure in this spring chamber is controlled by the vehicle speed. It changes depending on.

Since the pressure in the spring chamber changes in accordance with the vehicle speed, the amount of relative movement between the spool and the sleeve also changes, and the amount of overlap between the groove and the recess is controlled in accordance with the vehicle speed.

(Effects of the Present Invention) Since the present invention is configured as described above, the integral power steering device can also be provided with a steering reaction force mechanism. Therefore, the safety during driving is extremely high.

(Embodiment of the present invention) In the embodiment shown in FIGS. 1 to 3, a spool SP is fitted to the stub shaft 10, and a guide groove 50 is formed in the inner circumference of the spool SP in the axial direction. ing. A regulating pin 51 erected on the stub shaft 10
By inserting the spool SP into the guide groove 50, the spool SP is slidable in the axial direction of the stub shaft IO and rotates integrally with the spool SP in the rotational direction.

There are lands 55 on the outer periphery of the spool SP made as above.
and concave grooves 56 are formed alternately, but these lands 5
5 and the groove 5B are each inclined at an angle α with respect to a tangent perpendicular to the axial direction of the spool Sp.

Further, on the inner circumference of the sleeve SL provided on the outer circumference of the spool SP, convex portions 57 and concave portions 58 are alternately formed, and both of these convex portions 57 and concave portions 58 are similar to the lands and concave grooves described above. is tilted by an angle α.

Further, both ends of the spool SP are connected to a spring chamber 59,
In addition to facing the BO, this spring chamber 59.60
The springs 61 and 62 are interposed in the spring 131.
．． A spring force of 132 is applied to the spool SP. Then, the passages B3.64 are connected to each of the spring chambers 59.80, and the passages 63, 84 are connected to each other.
A variable aperture 85.6B is provided in the
The spring chambers 58 and 60 are communicated with the tank T via the spring chambers 58 and 60. The variable aperture 85.6B automatically adjusts its opening according to the speed of the vehicle, and the opening is made smaller when the vehicle is running at high speed, and is made larger when the vehicle is running at low speed.

Further, each of the second annular groove 48 and the third annular groove 47 is connected to the variable aperture 65, via the fixed aperture 67, 68,
The passage 63 on the upstream side of 88 is connected to B4.

The configuration for controlling the opening degree of the variable throttle according to the vehicle speed can be achieved using known means 1, for example, by using a solenoid valve as the variable throttle,
A controller is installed that oscillates an electrical signal according to the vehicle speed,
The solenoid valve may be controlled by this controller.

The configuration other than the above is completely the same as that of the prior art described above.

When the handle is turned to the right as in the conventional case, pressure oil is supplied to the second annular groove 48 and a portion of the pressure oil is transferred to the fixed orifice 67 and the variable orifice 67.
It flows into tank T via 5.

When oil passes through the variable throttle 85 in this manner, a pressure difference is generated before and after the oil, and the pressure on the upstream side of the variable throttle 65 acts on the spring chamber 59.

The pressure inside the spring chamber 58 at this time varies depending on the opening degree of the variable throttle 65, that is, the vehicle speed of the vehicle, and becomes low pressure when traveling at low speeds and becomes high pressure when traveling at high speeds.

Therefore, during low-speed running, the variable throttle 65 maintains a substantially fully open state, and the pressure inside the spring chamber 65 becomes the tank pressure. When the spring chamber 65 reaches the tank pressure, the spool SP maintains the state shown in FIG. 2.3 in the axial direction by the action of the two springs 65 and 66. That is, in FIG. 2 where the spool SP and sleeve SL are kept in a neutral state, the lap height 1 and the height 2 of the concave groove of the spool SP are equal.

Therefore, if you turn the handle clockwise in the above condition,
The spool SP moves in the direction of the arrow in FIG. 3, and the amount of overlap between the groove 56 and the recess 58 becomes relatively maximum.

On the other hand, when the vehicle is running at high speed, the pressure inside the spring chamber 59 increases, so the spool SP
As shown in the figure, it moves in the axial direction of the stub shaft 10 against the spring 62 on the opposite side. When the spool SP moves in the axial direction, the overlap irritation 1 between the groove 56 and the groove 58 decreases.

Therefore, even if the steering wheel is turned to the right in this state, the amount of wrap Ml will be relatively smaller than when the vehicle is running at low speed. As the wrap amount decreases, the flow rate supplied to the pressure chamber 48 also decreases, so the power assist force by the piston 1 becomes weaker.

In other words, according to this embodiment, the spool sp is movable in the axial direction, and the opening degree of the variable throttle B5.66 is changed according to the vehicle speed, so when driving at high speed, the steering wheel is operated It feels heavy, and when driving at low speeds, it becomes lighter.

[Brief explanation of the drawing]

Drawings 1 to 4 show embodiments of this invention.
The figure is a cross-sectional view of the main parts, Figure 2 is a developed view of the spool and sleeve in a neutral state, Figure 3 is a developed view of the spool and sleeve with the handle turned off, and Figure 4 is a diagram showing how the spool changes depending on the vehicle speed. Developed view of the spool moving in the axial direction, Nos. 5 to 9
The figure shows a conventional example in which a rotary valve is applied to an integral type integral power steering device, and Fig. 5 is a cross-sectional view.
Figure 6 is a sectional view of the main parts, Figure 7 is a sectional view showing the relationship between the stopper provided on the stub shaft and the worm shaft, and Figure 8 is the flow of hydraulic oil with the spool and sleeve in neutral position. FIG. 9 is an explanatory diagram showing the flow of hydraulic oil when the spool is rotated. SP...Spool, 55...Land, 56...Concave groove, SL...Sleeve, 57...Protrusion, 58...
Recessed portion, 53.60...Spring chamber, 63.64...
・Aisle, 65.66...variable aperture.

Claims (1)

[Claims] The sleeve includes a sleeve having alternating convex portions and concave portions formed on the inner periphery, and a spool having alternating lands and concave grooves corresponding to the convex portions and concave portions, and the spool is installed inside the sleeve so as to be rotatable relative to the sleeve. , a rotary valve is used that connects the actuator boat to the pump or tank by relatively rotating the sleeve and spool to connect or cut off the communication between the recess in the sleeve and the groove in the spool. In the integral power steering device, the sleeve and the spool are movable relative to each other in the axial direction, and both or one of the recessed portion and the groove is inclined with respect to a tangent perpendicular to the axial direction of the sleeve and the spool. Moreover, the spring chamber facing both ends of the spool is communicated with the tank via a variable throttle that adjusts the throttle opening depending on the vehicle speed, and the upstream side of the variable throttle is connected to a passageway leading to the actuator. An integral power steering device connected to the