JP3384024B2 - Servo valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo valve used for a power steering device of an automobile. 2. Description of the Related Art As shown in FIG. 4, a rotary type servo valve used in a power steering device of an automobile or the like has a characteristic that when a handle is turned, a hydraulic pressure is applied while a handle torque TM is small. There is a region where the assist does not work, when ing than there is handle torque value p, gently assist increases, further handle torque is increased, two-stage rapid assist was made to increase becomes more than q Breaking characteristics are required. [0003] In order to obtain such pressure characteristics, there is a technique disclosed in, for example, JP-A-63-215462. As shown in FIGS. 5 and 6, the control land of the sleeve valve member 40 that underlaps with the land 31 of the rotor valve member 30 at the neutral position is provided at the fitting portion of the rotor valve member 30 and the sleeve valve member 40. In this configuration, a pressure control land portion Z1 having a pressure control land 411 and a pressure characteristic adjustment land portion Z2 having an adjustment land 412 of the sleeve valve member 40 overlapping the land portion 31 at the neutral position are arranged. [0004] As will land portion 31 of the pressure control land portion Z1 shown in FIG. 6 (A), the supply chamber 32 and the supply chamber the supply holes 43 with the relative rotation of both valve member communicates
32 and the land 31 are interposed between the discharge holes 33
There first chamfer 36 for controlling the diaphragm so as to gradually reduce the area of communication between the discharge chamber communicating is formed on the land portion 31 of the pressure characteristic-adjusting land portion Z2 has at one end face, FIG. 6 (B ), A second chamfer 37 for controlling the squeezing so as to gradually increase the communication area between the supply chamber 32 and the discharge chamber with the relative rotation of the two valve members is provided on the other end face.
As shown in FIG. 6 (C), a third chamfer 38 for controlling the aperture so as to gradually reduce the communication area between the supply chamber 32 and the discharge chamber is formed. By these three types of chamfering operations, the supply holes 44 and 45 are controlled so as to have a two-step bending assist characteristic according to the handle torque TM (rotation angle). [0005] In the above configuration,
The direction of the flow of the chamfered narrowing section is determined by the supply chamber 32 and the discharge chamber.
Between the supply chamber 32 and the discharge chamber and the discharge chamber.
Since it is configured by a combination of both directions from the exit chamber side to the supply chamber side , especially from the discharge chamber side to the supply chamber side
The flow in the direction toward changes the flow line pattern depending on the valve opening, and accordingly, the appearance of abnormal noise (shoe noise of the fluid restrictor) differs, and the sound pressure difference increases. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is relatively rotatable with respect to each other.
The sleeve valve member and the rotor valve member
The inner circumference of the sleeve valve member has a plurality of circumferential grooves and grooves.
And lands are provided alternately on the outer periphery of the rotor valve member.
Is a circumferential duplication corresponding to the concave groove and the land, respectively.
A number of lands and concave grooves are provided alternately, and these two valve members are
Supply the pressurized fluid to the groove or land.
The supply hole and the pressurized fluid supplied from the supply hole
Supply port for distributing and supplying to the
A discharge port for discharging the pressure fluid and a pressure fluid
In a servo valve having a discharge hole for discharging,
The supply hole is formed in the groove of the sleeve valve member.
And a supply chamber formed in the rotor valve member facing the supply chamber.
The pressure control land and the front of the sleeve valve member.
Supply ports are formed in the lands on both sides of the supply chamber.
The rotor valve portion facing the land portion where the port is formed
A first pressure control chamber provided in a groove of the material,
Rotor sandwiching the first pressure control chamber on both sides of the land for use
A rectifying land formed on the valve member;
The rotor valve member sandwiching the control chamber and the rectifying land.
A discharge chamber provided with a discharge hole formed in a concave groove of
Recesses on both sides of the land of the sleeve valve member facing the chamber
A second pressure control provided with the discharge port formed in the groove
And a second pressure control in the rectifying land.
A communication area between the second pressure control chamber and the discharge chamber at one end on the control chamber side.
Of chamfer to control iris so that it changes gradually
And the sleeve valve having the supply port formed at the other end.
From the first pressure control chamber always in close contact with the land of the member
Forming a closing part for blocking the flow of oil to the second pressure control chamber;
It is characterized by the fact that: [0007] By the action structure of the surface in the direction of flow of the pressure fluid
It regulates the flow in one direction along the taking part, stabilizes cavitation and reduces the generation of abnormal noise. An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, a power steering apparatus employing the servo valve of the present invention will be described. The output shaft 12 is rotatably supported in the gear housing 10 and the valve housing 11 fixed to each other via bearings 18 and 18a.
The pinion 12a of the output shaft 12 has a rack tooth 15 of a rack shaft 15 slidably supported in a direction crossing the pinion 12a.
a. The power cylinder 1 is mounted on the rack shaft 15.
6 is fixed, and the steered wheels are connected via a link mechanism (not shown). An input shaft 13 connected to a steering handle via a handle shaft is provided in the housings 10 and 11.
The output shaft 12 is supported coaxially with bearings 19 and 19 a via bearings 19 and 19 a. The two shafts 12 and 13 are connected by a torsion bar 14 so as to be elastically and relatively rotatable. These two shafts 1
A rotary servo valve 20 according to the present invention is provided between 2 and 13. The rotary type servo valve 20 includes a rotor valve member 30 formed on the input shaft 13,
A sleeve valve member 40 rotatably fitted to the outer peripheral surface and the inner peripheral surface 11a of the valve housing 11 and connected to the output shaft 12 by a connecting pin 25, comprises a supply port 51, a discharge port 52, and a pair of supply ports. A rotary 4-port throttle switching valve having 53 and 54 is formed. [0010] That is, as shown in FIG. 2, the inner periphery of the sleeve valve member 40 groove 42 is formed, the land portion 41 between respective grooves 42 are formed. In addition, the groove 42 of the sleeve valve member 40 is formed on the outer periphery of the rotor valve member 30.
Are formed, and a pressure control land 31A and a rectification land 31B are formed, and a concave groove 32 is formed between each of the lands 31A and 31B. A supply hole 43 is opened in the land portion 41 of the sleeve valve member 40, and each supply hole 43 communicates with a supply port 51 to which a pressure fluid from a supply pump 50 is supplied. As shown in FIG. 3, the supply hole 43 of the sleeve valve member 40 in the groove 32 of the rotor valve member 30 is formed.
The one that communicates with the supply chamber R0 forms a first pressure control chamber R1, and the one that communicates with the discharge port 54A of the sleeve valve member 40 forms a discharge chamber R3. This discharge chamber R
3, a discharge hole 33 is opened, as shown in FIGS.
The discharge hole 33 communicates with a discharge port 52 communicating with a reservoir 57 through a passage 55 between the input shaft 13 and the torsion bar 14 and a through hole 56 provided in the input shaft 13. The land portion 41 of the sleeve valve member 40
The supply ports 53 and 54 communicating with the left and right chambers 16a and 16b of the power cylinder 16 are formed in the land portions 41A on both sides of the supply chamber R0.
Reference numerals 3 and 54 denote the first pressure control chamber R1 of the rotor valve member 30.
Is in communication with The concave groove 42 of the sleeve valve member 40
Among them, those other than the supply chamber R0 form a second pressure control chamber R2, and the second pressure control chamber R2
The discharge port 54A communicating with the discharge chamber R3 is formed. The pressure control land 31A of the rotor valve member 30 is located at a position corresponding to the supply chamber R0 of the sleeve valve member 40, and has chamfers u at both ends. Further, the rectifying land 31B of the rotor valve member 30 is located at a position corresponding to the second pressure control chamber R2 of the sleeve valve member 40. This rectifying land 31B
Is formed on one side with a chamfer N for restricting and controlling the communication area between the second pressure control chamber R2 and the discharge chamber R3 so as to gradually change with the relative rotation of the two valve members 30, 40. A closing portion S that is always in close contact with the land portions 41 and 41A of the member 40 is formed. According to the present invention, when the rotor valve member 30 and the sleeve valve member 40 rotate relative to each other from the neutral position shown in FIGS. 2 and 3, the pressure control land 31A is supplied by the chamfer u. The communication area between the chamber R0 and the first pressure control chamber R1 is controlled to expand and contract to supply oil to the left or right chambers 16a and 16b of the power cylinder 16.
Also, the right or left chamber 16b, 16a of the power cylinder 16
Oil is discharged from the discharge port 54A of the sleeve valve member 40 to the second
The gas is discharged from the discharge hole 33 through the pressure control chamber R2 and the discharge chamber R3 of the rotor valve member 30. At this time, the rectifying land portion 31B enters the supply chamber R0 and the first pressure control chamber R1 because the closing portion S is always closely closed to the lands 41 and 41A of the sleeve valve member 40. The flow of the collected oil to the second pressure control chamber R2 is always shut off, and the flow is regulated in one direction along the chamfer N from the second pressure control chamber R2 to the discharge chamber R3. Accordingly, in all of the pressure control lands 31A and the rectification lands 31B, the oil flowing through the chamfers u and N flows from the second pressure control chamber R2 to the discharge chamber R3.
It is fixed in only one direction of the flow , so that a change in the streamline pattern due to the valve opening can be prevented, cavitation is stabilized, and abnormal noise is reduced. As described above, according to the present invention, each other
Valve member and rotor fitted to be rotatable relative to each other
A valve member, and the inner circumference of the sleeve valve member is circumferentially
A plurality of grooves and lands are provided alternately, and the rotor valve
Corresponds to the groove and land on the outer periphery of the member
A plurality of lands and concave grooves are provided alternately on the circumference of
Supply pressure fluid to the concave groove or land of both valve members
And a pressure flow supplied from the supply hole.
A supply port for distributing and supplying the body to the controlled device, and
A discharge port for discharging the pressurized fluid of the controlled
Servo valve with a discharge hole for discharging pressure and pressure fluid
The supply hole is formed in the groove of the sleeve valve member.
A supply chamber, and a rotor facing the supply chamber.
A pressure control land formed on the valve member;
Supply ports are formed in the lands on both sides of the supply chamber of the valve valve member.
Before the supply port faces the land where the supply port is formed.
A first pressure control chamber provided in the concave groove of the rotor valve member;
The first pressure control chamber is provided on both sides of the pressure control land.
A rectifying land formed on the sandwiched rotor valve member;
The first pressure control chamber and the rectifying land portion interposed therebetween;
Discharge provided by forming a discharge hole in a concave groove of a rotor valve member
Chamber and a land of the sleeve valve member facing the discharge chamber
The discharge port is formed in the concave groove on both sides of the part
A second pressure control chamber;
The second pressure control chamber and the discharge chamber are provided at one end on the side of the second pressure control chamber.
For controlling the aperture so that the area of communication with the gradual change
The supply port is formed at the other end.
The first pressure is always kept in close contact with the land of the sleeve valve member.
Closure to shut off oil flow from control room to second pressure control room
The oil flow is equal to the first pressure in all of the pressure control land portion and the rectification land portion.
Oil entering the force control chamber always blocks the flow to the second pressure control chamber.
From the second pressure control chamber to the discharge chamber along the chamfer
Is kept constant in one direction flows Te, it is possible to reduce the abnormal sound cavitation stably.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a power steering apparatus provided with a rotary servo valve showing a first embodiment of the present invention. FIG. 2 is a rotary type showing a first embodiment of the present invention. FIG. 3 is a cross-sectional view of a main part of a rotary type servo valve showing a first embodiment of the present invention; FIG. 4 is a cross-sectional development view of a steering pressure with respect to a steering wheel torque in the servo valve; Characteristic diagram [Fig. 5] Cross-sectional development view of a main part of a rotary type servo valve showing the prior art [Fig. 6] Detailed cross-sectional view of a chamfered portion of Fig. 5 showing the prior art [Explanation of reference numerals] 20 Rotary type servo valve Reference Signs List 30 Rotor valve member 31A Pressure controlling land 31B Rectifying land 33 Discharge hole 40 Sleeve valve member 41 Land 41A Land 43 Supply hole N Chamfer S Closure

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-215462 (JP, A) JP-A-5-301571 (JP, A) JP-A-60-15265 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B62D 5/083

Claims (1)

(57) [Claims] [Claim 1] Sleeves fitted so as to be relatively rotatable with each other.
A sleeve member comprising a valve member and a rotor valve member;
Multiple concave grooves and lands are alternately arranged on the inner circumference of the material
The concave groove and the run are provided on the outer periphery of the rotor valve member.
Multiple lands and concave grooves on the circumference corresponding to the
Are provided alternately, and the concave grooves or land portions of these valve members are provided.
And a supply hole for supplying pressure fluid to the
To distribute the supplied pressure fluid to the controlled equipment
To discharge the pressure fluid of the supply port and the controlled device.
And a discharge port for discharging pressure fluid.
In the above servo valve, the supply hole is formed and provided in the concave groove of the sleeve valve member.
The supply chamber and the rotor valve member facing the supply chamber.
The formed pressure control land portion and the sleeve valve member
Forming supply ports in the lands on both sides of the supply chamber;
The rotor facing a land portion having a supply port formed therein
A first pressure control chamber provided in a concave groove of the valve member;
B that sandwiches the first pressure control chamber on both sides of the control land.
A rectifying land formed on the data valve member;
The rotor valve sandwiching the pressure control chamber and the rectifying land.
A discharge chamber provided with a discharge hole formed in a concave groove of the member,
Both sides of the land portion of the sleeve valve member facing the discharge chamber
The second pressure provided by forming the discharge port in the concave groove of
A control chamber, and the rectifying land has one end on the second pressure control chamber side.
Gradually changes the communication area between the second pressure control chamber and the discharge chamber.
Forming a chamfer for controlling the drawing so that the other end
Land portion of the sleeve valve member having a supply port formed
From the first pressure control chamber to the second pressure control chamber
A servo valve characterized by forming a closing part for shutting off oil flow to the motor .