JPS6257545B2 - - Google Patents
Info
- Publication number
- JPS6257545B2 JPS6257545B2 JP53125208A JP12520878A JPS6257545B2 JP S6257545 B2 JPS6257545 B2 JP S6257545B2 JP 53125208 A JP53125208 A JP 53125208A JP 12520878 A JP12520878 A JP 12520878A JP S6257545 B2 JPS6257545 B2 JP S6257545B2
- Authority
- JP
- Japan
- Prior art keywords
- control valve
- working
- valve spool
- chamber
- spool
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000007935 neutral effect Effects 0.000 claims description 3
- 230000002079 cooperative effect Effects 0.000 claims 2
- 230000000875 corresponding effect Effects 0.000 claims 1
- 238000010276 construction Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000001965 increasing effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/08—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by type of steering valve used
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Power Steering Mechanism (AREA)
- Multiple-Way Valves (AREA)
- Actuator (AREA)
Description
【発明の詳細な説明】
本発明は、ステアリングホイールの操向運動を
流体圧的に支援するために不平衡な作動シリンダ
をもつたパワーステアリング装置の制御弁に関す
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control valve for a power steering device with unbalanced actuating cylinders for hydraulically supporting the steering movement of a steering wheel.
流体圧的なパワーステアリング装置の場合、唯
一の流体圧式作動シリンダを用いること、すなわ
ちピストンの片側からだけ伸びている１本のピス
トンロツドを有している作動シリンダを用いるこ
とが、構造上およびコスト上望ましい。 In the case of hydraulic power steering systems, it is advantageous both structurally and cost-effectively to use only one hydraulic actuating cylinder, that is, to have one piston rod extending from only one side of the piston. desirable.
不平衡な作動シリンダをもつたパワーステアリ
ング装置は、たとえばドイツ連邦共和国特許出願
公開第1959020号公報で知られている。このパワ
ーステアリング装置は、相対する制御方向におい
て制御力を非対称に与える必要があり、両操向方
向からの復帰力および復帰速度があまり大きくな
くかつ異なつた大きさになるなどという欠点を有
している。さらに多くの場合、弁の中立位置にお
いて系統圧力によつて発生されて作動ピストンに
作用する力は非常に不利である。 A power steering device with unbalanced working cylinders is known, for example, from DE 1959 020 A1. This power steering device has the disadvantage that it is necessary to apply control force asymmetrically in opposing control directions, and that the return force and return speed from both steering directions are not very large and have different magnitudes. There is. Furthermore, in many cases the forces which are generated by the system pressure and which act on the actuating piston in the neutral position of the valve are very disadvantageous.
系統圧力および面積差に合わされた作動室内に
おける差圧によつて、作動ピストンに対して力の
平衡が生じさせられる。多くの場合、制御弁内に
作用する中心ばねを、小面積のピストン面に相応
した高い圧力が生ずるように、すなわち制御弁が
流体圧的中心から偏心しておかれるように調整す
ることによつて間に合わせている。 The differential pressure in the working chamber, matched to the system pressure and the area difference, creates a force balance on the working piston. This is often achieved by adjusting the central spring acting in the control valve in such a way that a correspondingly high pressure is generated on a small area of the piston surface, i.e. the control valve is kept eccentric from the hydraulic center. I'm making time.
この処置によれば、その特性曲線が中心から直
ぐに上昇している制御弁をもつたパワーステアリ
ング装置の場合だけ、満足できる作用が達成でき
る。もしこれがたとえば乗用車のパワーステアリ
ング装置のような場合でなければ、左右の操向力
は大きく異なつてしまう。 With this measure, a satisfactory effect can only be achieved in power steering systems with control valves whose characteristic curve rises directly from the center. If this were not the case, for example, in a power steering system for a passenger car, the left and right steering forces would be significantly different.
本発明の目的は、流体圧的中心において必要な
差圧を生ずるような制御弁を提供することにあ
る。 It is an object of the invention to provide a control valve which produces the required pressure differential at the hydraulic center.
この目的は、本発明によれば、流体圧的なパワ
ーステアリング装置において、制御弁の中に２個
の絞り装置が設けられ、これらの絞り装置が弁ス
プールの位置に無関係に小面積側の作動室におけ
る系統圧力をせき止めることによつて達成でき
る。 According to the invention, the present invention provides a hydraulic power steering device in which two throttle devices are provided in the control valve, and these throttle devices operate on the small area side regardless of the position of the valve spool. This can be achieved by damming the system pressure in the chamber.
以下、図面に示す実施例に基づいて本発明を詳
細に説明する。 Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.
制御弁１は弁体２と油入口室３内に横にかつ長
手軸心に対して偏心して配置された２個の制御弁
スプール４ａ，４ｂとを有している。これらの制
御弁スプール４ａ，４ｂはそれぞれひとつの孔
５，６を有しており、これらの孔５，６の中には
制御弁スプール４ａ，４ｂを駆動するために用い
るピン（図示せず）が係合している。弁体２は孔
７を有しており、この孔７を通してねじり棒がス
テアリングホイール（図示せず）の回転運動をピ
ニオンを介してラツクに伝える。流体圧が消失し
た場合、自動車をステアリングホイールから被操
向車輪へのこの機械的な連結装置を介して純粋に
手動で操向することもできる。 The control valve 1 has a valve body 2 and two control valve spools 4a, 4b arranged laterally in the oil inlet chamber 3 and eccentrically with respect to the longitudinal axis. These control valve spools 4a, 4b each have one hole 5, 6, and in these holes 5, 6 there is a pin (not shown) used to drive the control valve spools 4a, 4b. is engaged. The valve body 2 has a hole 7 through which a torsion rod easily transmits the rotational movement of a steering wheel (not shown) via a pinion. In the event of a loss of fluid pressure, it is also possible to steer the motor vehicle purely manually via this mechanical coupling from the steering wheel to the steered wheel.
作動媒体は配管８を介して制御弁１に送られ
る。作動媒体は、制御弁スプール４ａにある入口
制御縁９、制御弁スプール４ｂにある入口制御縁
９′および配管１０，１０′を介して不平衡の作動
シリンダ１２の作動室１１，１１′に送られる。
この作動媒体は、分岐箇所１３，１３′、制御弁
スプール４ｂにある戻り口制御縁１４および制御
弁スプール４ａにある戻り口制御縁１４′を介し
て、弁体２の孔１５ａを通つて戻り配管１５に流
入する。 The working medium is sent to the control valve 1 via the pipe 8. The working medium is delivered to the working chambers 11, 11' of the unbalanced working cylinder 12 via an inlet control lip 9 on the control valve spool 4a, an inlet control lip 9' on the control valve spool 4b and lines 10, 10'. It will be done.
This working medium returns through the bore 15a of the valve body 2 via the branch points 13, 13', the return control lip 14 on the control valve spool 4b and the return control lip 14' on the control valve spool 4a. It flows into the pipe 15.
制御縁および油配管が作用的に対称に配置され
ている場合、分岐箇所１３，１３′における圧力
は同じであるので、作動シリンダ１２の作動室１
１，１１′は同じ圧力になる。分岐箇所１３と戻
り口制御縁１４との間の絞り１６によつて、作動
媒体は絞り１６の手前でせき止められ、それによ
つて小面積の作動室１１内の圧力が作動室１１′
に比べて高くなる。絞り１６の前後には作動媒体
の流れに関連した差圧が生ずる。絞り１６の後方
の圧力は両作動室１１，１１′に対して共通の戻
り配管１５内の圧力によつて決まる。すなわち、
絞り１６の後方の圧力は作動室１１′の圧力に
ほゞ相応している。今や配管１０，１０′内の抵
抗が非対称であるために、配管１０内の流量は配
管１０′内の流量よりも少ない。配管１０におけ
る減少流量によつて絞り１６の作用は限定され
る。最適値に達した後は絞り１６の断面積を小さ
くしても、絞り１６の前後の圧力差はほとんど高
まらない。 If the control lip and the oil line are arranged operatively symmetrically, the pressures at the branch points 13, 13' are the same, so that the working chamber 1 of the working cylinder 12
1 and 11' have the same pressure. By means of the throttle 16 between the branch point 13 and the return control edge 14, the working medium is blocked in front of the throttle 16, so that the pressure in the small-area working chamber 11 is reduced to the working chamber 11'.
higher than that of A pressure difference occurs across the throttle 16 that is related to the flow of the working medium. The pressure behind the throttle 16 is determined by the pressure in the return line 15, which is common to both working chambers 11, 11'. That is,
The pressure behind the throttle 16 corresponds approximately to the pressure in the working chamber 11'. The flow rate in line 10 is less than the flow rate in line 10' because the resistance in lines 10, 10' is now asymmetric. The reduced flow rate in the line 10 limits the action of the throttle 16. After reaching the optimum value, even if the cross-sectional area of the throttle 16 is made smaller, the pressure difference across the throttle 16 will hardly increase.
入口制御縁９′と分岐箇所１３′との間の配管１
０′に絞り１６と同じ大きさの第２の絞り１６′を
設けることによつて、作動媒体の均一な流量分布
が保証され、絞り１６′の昇圧作用は大面積の作
動室１１′に影響を及ぼさない。両方の絞り１
６，１６′の大きさを変えることによつて、制御
弁１の中立位置におけるシリンダ室内の所望の圧
力差が得られ、それによつて作動ピストン１７に
力が作用しない。絞り１６，１６′はたとえば配
管１０，１０′を細くすることによつても形成で
きる。 Piping 1 between the inlet control edge 9' and the branch point 13'
By providing a second throttle 16' with the same size as the throttle 16 at 0', a uniform flow distribution of the working medium is ensured, and the pressure increasing action of the throttle 16' affects the large area of the working chamber 11'. does not affect both apertures 1
By varying the dimensions of 6, 16', the desired pressure difference in the cylinder chamber in the neutral position of the control valve 1 is obtained, so that no forces act on the working piston 17. The throttles 16, 16' can also be formed, for example, by narrowing the pipes 10, 10'.
第２図は、制御弁がアキシヤルスライド弁とし
て知られている構造で作られているような本発明
の別の実施例を示している。第２図の制御弁にお
いて第１図の実施例と同一部分には第１図と同一
符号が付されている。 FIG. 2 shows another embodiment of the invention in which the control valve is made of a construction known as an axial slide valve. In the control valve of FIG. 2, the same parts as in the embodiment of FIG. 1 are given the same reference numerals as in FIG.
ステアリングホイールの回転は、軸方向に移動
できる制御弁スプール４に伝達される。昇圧のた
めに必要な絞り１６，１６′は、一方では小面積
の作動室１１にある戻り口制御縁１４に、他方で
は大面積の作動室１１′にある入口制御縁９′に、
制御弁１の内周面と制御弁スプール４との間に設
けられている。 The rotation of the steering wheel is transmitted to an axially movable control valve spool 4. The throttles 16, 16' required for the pressure increase are located on the one hand in the return control edge 14 in the small-area working chamber 11 and on the other hand in the inlet control edge 9' in the large-area working chamber 11'.
It is provided between the inner peripheral surface of the control valve 1 and the control valve spool 4.
第３図は、制御弁が回転弁として知られている
構造で作られているような本発明の実施例を示し
ている。 FIG. 3 shows an embodiment of the invention in which the control valve is made of a construction known as a rotary valve.
作動媒体は、配管８，８ａ，８ｂ，８ｃおよび
それに従属された３つの入口制御縁９を介して小
面積の作動室１１に流入するか、ないしは３つの
入口制御縁９′を介して大面積の作動室１１′に流
入する。 The working medium enters the small-area working chamber 11 via the pipes 8, 8a, 8b, 8c and the three inlet control edges 9 dependent thereon, or enters the large-area working chamber 11 via the three inlet control edges 9'. into the working chamber 11'.
作動媒体は、それぞれ３つの戻り口制御縁１
４，１４′、制御弁スプール４にある３つのラジ
アル孔１５ａ，１５ｂ，１５ｃを介して戻り配管
１５に戻る。 The working medium is supplied to each of the three return control edges 1
4, 14', and returns to the return pipe 15 through three radial holes 15a, 15b, 15c in the control valve spool 4.
両作動室１１，１１′における差圧は、３つの
戻り口制御縁１４の直後で作用する３つの絞り１
６、および３つの入口制御縁９′の直前で作用す
る３つの戻り口制御縁１４によつて保証される。 The pressure difference in the two working chambers 11, 11' is caused by three throttles 1 acting immediately after the three return control edges 14.
6, and three return control edges 14 acting immediately before the three inlet control edges 9'.
本発明に基づく制御弁の場合、絞り１６，１
６′は、制御弁スプール４ないし制御弁１のケー
シングの孔内周面にある突起によつて、リング
状、多面状あるいは平面状に作られる。 In the case of the control valve according to the invention, the throttle 16,1
6' is formed into a ring shape, a multifaceted shape, or a planar shape by a projection on the inner peripheral surface of the hole of the control valve spool 4 or the control valve 1 casing.
第１図は回転ピストン構造の制御弁の横断面
図、第２図はアキシヤルピストン構造の制御弁の
長手断面図、第３図は回転弁構造の制御弁の横断
面図である。
１…制御弁、４…制御弁スプール、８…入口配
管、９，９′…入口制御縁、１０，１０′…配管、
１１…小面積の作動室、１１′…大面積の作動
室、１２…作動シリンダ、１３，１３′…分岐箇
所、１４，１４′…戻り口制御縁、１５…戻り配
管、１６，１６′…絞り。
FIG. 1 is a cross-sectional view of a control valve having a rotary piston structure, FIG. 2 is a longitudinal cross-sectional view of a control valve having an axial piston structure, and FIG. 3 is a cross-sectional view of a control valve having a rotary valve structure. 1... Control valve, 4... Control valve spool, 8... Inlet piping, 9, 9'... Inlet control edge, 10, 10'... Piping,
11... Small area working chamber, 11'... Large area working chamber, 12... Working cylinder, 13, 13'... Branch point, 14, 14'... Return port control edge, 15... Return piping, 16, 16'... Aperture.
Claims (1)
作用面を有し、作動配管を介して制御弁に接続さ
れ、この制御弁がハンドルの回転運動によつて駆
動され、開放中央位置並びに入口配管に接続され
た室および戻り配管に接続された室を有し、その
場合弁の中立位置においてこれらの室に作動シリ
ンダの両方の作動室が同時に接続され、専ら小さ
な作用面を有する作動室から圧力媒体を戻すため
に用いる配管部分の中に、制御弁の運動によつて
その横断面が変わらない絞りが組み込まれている
ような液圧式パワーステアリング装置において、 制御弁１の運動によつてその横断面が変わらな
い絞り１６′が、入口配管に接続された室と、大
きな作用面を有する作動室に通じる配管１０′と
の間に配置されていることを特徴とする液圧式パ
ワーステアリング装置。 ２ 絞り１６および１６′が相応した配管１０お
よび１０′の狭隘部として形成されていることを
特徴とする特許請求の範囲第１項記載の制御弁。 ３ 絞り１６および１６′が、制御弁スプール４
に設けられた切欠部と、制御弁スプール４を収容
する孔の円筒状壁との協働作用によつて形成され
ていることを特徴とする特許請求の範囲第１項記
載の制御弁。 ４ 絞り１６および１６′が、制御弁スプール４
を収容する孔の表面に加工された切欠部と、制御
弁スプール４の円筒状部分との協働作用によつて
形成されていることを特徴とする特許請求の範囲
第１項記載の制御弁。 ５ 絞り１６および１６′が、リング状あるいは
平面状に形成されていることを特徴とする特許請
求の範囲第３項または第４項の制御弁。 ６ 絞り１６および１６′が同じ自由横断面積で
作られていることを特徴とする特許請求の範囲第
１項ないし第５項のいずれか１項に記載の制御
弁。[Scope of Claims] 1. The pistons of the working cylinder have working surfaces of different sizes and are connected via working piping to a control valve, which control valve is driven by the rotational movement of the handle and has an open central position and a chamber connected to the inlet pipe and a chamber connected to the return pipe, in which case in the neutral position of the valve both working chambers of the working cylinder are connected simultaneously to these chambers and have an exclusively small working surface. In a hydraulic power steering device in which a restriction whose cross section does not change due to the movement of the control valve 1 is incorporated in the piping section used for returning the pressure medium from the working chamber, Hydraulic power supply, characterized in that a throttle 16', whose cross section does not change, is arranged between the chamber connected to the inlet pipe and the pipe 10' leading to the working chamber, which has a large working area. Steering device. 2. Control valve according to claim 1, characterized in that the throttles 16 and 16' are formed as constrictions in the corresponding lines 10 and 10'. 3 Restrictions 16 and 16' are connected to control valve spool 4
2. The control valve according to claim 1, wherein the control valve is formed by a cooperative action between a notch provided in the control valve spool and a cylindrical wall of the hole that accommodates the control valve spool. 4 Restrictions 16 and 16' are connected to control valve spool 4
The control valve according to claim 1, characterized in that the control valve is formed by a cooperative action of a notch machined on the surface of the hole accommodating the control valve spool 4 and a cylindrical portion of the control valve spool 4. . 5. The control valve according to claim 3 or 4, wherein the throttles 16 and 16' are formed in a ring shape or a planar shape. 6. Control valve according to any one of claims 1 to 5, characterized in that the throttles 16 and 16' are made with the same free cross-sectional area.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2745987A DE2745987C2 (en) | 1977-10-13 | 1977-10-13 | Hydraulic power steering, in particular for motor vehicles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5464333A JPS5464333A (en) | 1979-05-24 |
| JPS6257545B2 true JPS6257545B2 (en) | 1987-12-01 |
Family
ID=6021313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12520878A Granted JPS5464333A (en) | 1977-10-13 | 1978-10-13 | Control valve for power steering with a unbalanced actuation cylinder |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5464333A (en) |
| BR (1) | BR7806744A (en) |
| CS (1) | CS222667B2 (en) |
| DE (1) | DE2745987C2 (en) |
| ES (1) | ES474117A1 (en) |
| FR (1) | FR2405855A1 (en) |
| GB (1) | GB2005611B (en) |
| IT (1) | IT1106180B (en) |
| SE (1) | SE439910B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2931139C2 (en) * | 1979-08-01 | 1984-01-05 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Control valve with open center position |
| FR2508566A1 (en) * | 1979-11-26 | 1982-12-31 | Dba | Control flow distributor for hydraulic servo steering - has sleeve with flow ports and internal control piston, forming pressure control follower |
| GB2075932B (en) * | 1980-05-14 | 1983-09-01 | Cam Gears Ltd | Power assisted vehicle steering system |
| DE3122368A1 (en) * | 1981-06-05 | 1982-12-23 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | HYDRO CONTROL |
| US4587886A (en) * | 1983-04-28 | 1986-05-13 | Jidosha Kiki Co., Ltd. | Power steering device |
| JPS6133368A (en) * | 1984-07-26 | 1986-02-17 | Atsugi Motor Parts Co Ltd | power steering device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4920664U (en) * | 1972-05-26 | 1974-02-21 |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1153774A (en) * | 1955-06-10 | 1958-03-21 | Differential piston servo motor, in particular for motor vehicle steering gears | |
| GB796194A (en) * | 1956-01-05 | 1958-06-04 | Dewandre Co Ltd C | Improvements in or relating to power-assisted steering mechanisms for road vehicles |
| US3556155A (en) * | 1969-01-24 | 1971-01-19 | Caterpillar Tractor Co | Variable flow-modulated valve |
| FR2270467B1 (en) * | 1974-03-29 | 1977-09-30 | Mercier Bernard | |
| JPS5428735Y2 (en) * | 1974-08-15 | 1979-09-14 |
-
1977
- 1977-10-13 DE DE2745987A patent/DE2745987C2/en not_active Expired
-
1978
- 1978-10-02 GB GB7838862A patent/GB2005611B/en not_active Expired
- 1978-10-05 IT IT51392/78A patent/IT1106180B/en active
- 1978-10-06 SE SE7810507A patent/SE439910B/en not_active IP Right Cessation
- 1978-10-09 FR FR7828793A patent/FR2405855A1/en active Granted
- 1978-10-11 ES ES474117A patent/ES474117A1/en not_active Expired
- 1978-10-12 CS CS786635A patent/CS222667B2/en unknown
- 1978-10-12 BR BR7806744A patent/BR7806744A/en unknown
- 1978-10-13 JP JP12520878A patent/JPS5464333A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4920664U (en) * | 1972-05-26 | 1974-02-21 |
Also Published As
| Publication number | Publication date |
|---|---|
| IT1106180B (en) | 1985-11-11 |
| IT7851392A0 (en) | 1978-10-05 |
| SE439910B (en) | 1985-07-08 |
| BR7806744A (en) | 1979-05-08 |
| FR2405855A1 (en) | 1979-05-11 |
| FR2405855B1 (en) | 1984-08-24 |
| JPS5464333A (en) | 1979-05-24 |
| GB2005611B (en) | 1982-05-12 |
| CS222667B2 (en) | 1983-07-29 |
| ES474117A1 (en) | 1979-05-01 |
| GB2005611A (en) | 1979-04-25 |
| DE2745987A1 (en) | 1979-04-19 |
| DE2745987C2 (en) | 1982-10-21 |
| SE7810507L (en) | 1979-04-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0679895B2 (en) | Hydraulically operated steering device | |
| US3996838A (en) | Diverter valve for power steering with power beyond | |
| KR100529996B1 (en) | Fluid controller and fluid meter bypass arrangement | |
| JPH0249949B2 (en) | ||
| JP2628133B2 (en) | Automotive servo controller | |
| JPS6257545B2 (en) | ||
| US4558720A (en) | Closed-center controller for use with unequal area cylinder | |
| US4828067A (en) | Electronic power assist control steering system | |
| EP0775623B1 (en) | Steering control unit with flow amplification for unequal piston areas | |
| US4555975A (en) | Hydraulic steering | |
| US4016949A (en) | Hydrostatic load sensitive regenerative steering system | |
| US4377217A (en) | Power steering system having hydraulic reaction chambers | |
| JP4329089B2 (en) | Fluid controller | |
| US3990534A (en) | Power steering system | |
| JPH0134825B2 (en) | ||
| JPS61196875A (en) | 4-wheel steering device | |
| EP0672574B1 (en) | Power steering system | |
| GB2042443A (en) | Hydraulic powerassisted steering system | |
| US6769249B2 (en) | Low slip steering system and improved fluid controller therefor | |
| US3957129A (en) | Steering system | |
| JPH07509198A (en) | Especially automotive power steering equipment | |
| US3991656A (en) | Servo valve device in power steering apparatus | |
| US4846296A (en) | Hydraulic fluid pressure control system for use with power assist steering | |
| US5794736A (en) | Fluid control system for a vehicle power assisted steering mechanism | |
| JP2559724B2 (en) | Power steering hydraulic control device |