JPS6240222B2 - - Google Patents

Description

【発明の詳細な説明】 本発明は、自動車その他の車輌における動力操
向装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering system for an automobile or other vehicle.

従来、この種操向装置として、操向軸の回動に
伴い直進位置と左右各操向位置との３位置に切換
移動される切換弁を設け、該切換弁の各操向位置
への移動によりパワシリンダの左右両室の一方を
油圧ポンプその他の作動油圧源に、他方をタンク
に選択的に接続して、手動の操向に動力補助を与
える式のものは一般に知られるがこの場合該切換
弁は、直進位置において作動油圧源とタンクとを
接続するオープンセンタ型に構成されるを一般と
するもので、このものでは該直進位置において作
動油圧源からの圧油がタンクに流出してしまうの
で、車輌に他の油圧装置例えばパワブレーキ装置
等を装備するときはそのための油圧源を別個に用
意する必要がある。かくて該切換弁を、直進位置
においてパワシリンダの両室を共に作動油圧源又
はタンクの何れか一方に接続して、該切換弁を介
しての作動油圧源とタンクとの接続を常時は断つ
クローズドセンタ型に構成し、該作動油圧源を他
の油圧装置の油圧源として併用出来るようにする
ことが考えられるが、かかるクローズドセンタ型
切換弁は、例えば直進位置においてパワシリンダ
の両室をタンクに接続する型式の場合、各操向位
置への切換移動に伴い前記シリンダの一方の室を
先ずタンクから遮断して密閉状態とし、次いで作
動油圧源に接続せしめるようにして、作動油圧源
とタンクとの接続を断つようにしているから、該
室はタンクから遮断されて作動油圧源に接続され
る迄、前記操向軸に連動するピストンの一方から
他方に向う移動により密閉状態で膨張を続けて負
圧となり、該室内の油に気泡の発生を来たす不都
合を伴う。 Conventionally, this type of steering device has been provided with a switching valve that can be switched between three positions, a straight-forward position and left and right steering positions, as the steering shaft rotates, and the switching valve can be moved to each steering position. It is generally known that one of the left and right chambers of a power cylinder is selectively connected to a hydraulic pump or other hydraulic pressure source and the other to a tank to provide power assistance to manual steering; however, in this case, the switching The valve is generally configured as an open center type that connects the hydraulic pressure source and the tank in the straight-ahead position; in this valve, pressure oil from the hydraulic pressure source flows into the tank in the straight-ahead position. Therefore, when the vehicle is equipped with other hydraulic devices, such as a power brake device, it is necessary to separately prepare a hydraulic power source for the device. In this way, the switching valve is connected to both chambers of the power cylinder in the straight forward position to either the hydraulic pressure source or the tank, and the connection between the hydraulic pressure source and the tank via the switching valve is normally cut off. It is conceivable to configure it as a center type so that the operating hydraulic pressure source can be used in combination as a hydraulic source for other hydraulic devices, but such a closed center type switching valve can connect both chambers of the power cylinder to the tank in the straight-ahead position, for example. In the case of a type in which the cylinder is switched to each steering position, one chamber of the cylinder is first shut off from the tank to be in a sealed state, and then connected to the hydraulic pressure source, thereby establishing a connection between the hydraulic pressure source and the tank. Since the connection is cut off, the chamber continues to expand in a sealed state due to the movement of the piston linked to the steering shaft from one side to the other until it is isolated from the tank and connected to the hydraulic pressure source. This causes the inconvenience of air bubbles forming in the oil in the chamber.

又、同様に直進位置においてパワシリンダの両
室を作動油圧源に接続する型式の切換弁では、各
操向位置への移動に伴い前記シリンダの他方の室
を作動油圧源から遮断して、次いでタンクに接続
せしめるようにしているから、該室は作動油圧源
から遮断されてタンクに接続される迄、前記ピス
トンにより密閉状態で圧縮されて高圧となり、こ
の圧力が前記操向軸に作用して一時的に操向力が
増大し、操向感覚を悪化させる不都合を伴う。 Similarly, in a type of switching valve that connects both chambers of the power cylinder to the hydraulic pressure source in the straight-ahead position, the other chamber of the cylinder is cut off from the hydraulic pressure source as the cylinder moves to each steering position, and then the tank is connected to the hydraulic pressure source. Therefore, until the chamber is cut off from the hydraulic pressure source and connected to the tank, it is compressed in a sealed state by the piston and becomes high pressure, and this pressure acts on the steering shaft and temporarily This causes the disadvantage that the steering force increases and the steering feeling deteriorates.

第１発明は、かかる不都合を無くした装置を提
供することをその目的とするもので、操向軸の回
動に伴い直進位置と左右各操向位置との３位置に
切換移動される切換弁を備え、該切換弁の直進位
置において操向軸に咬うラツクと一体のピストン
を有するパワシリンダの左右両室を共にタンクに
接続して各操向位置への切換移動に伴い前記シリ
ンダの一方の室を先づタンクから遮断して密封状
態とし次いで作動油圧源に接続又は直進位置にお
いて前記パワシリンダの左右両室と共に作動油圧
源に接続して各操向位置への切換移動に伴い前記
シリンダの他方の室を作動油圧源から遮断して次
いでタンクに接続するクローズドセンタ型の車両
の動力操向装置において、前記パワシリンダの各
室と、前記直進位置において接続される前記作動
油圧源又はタンクとを前記切換弁に並列の各別の
側路を介して接続し、各側路に前記各室とタンク
とを接続するものでは各室への油の流入を許す一
方向弁を、前記各室と作動油圧源とを接続するも
のでは各室からの油の流出を許す一方向弁を各介
入せしめたことを特徴とする。 The object of the first invention is to provide a device that eliminates such inconveniences, and is a switching valve that can be switched between three positions, a straight-ahead position and left and right steering positions, as the steering shaft rotates. The right and left chambers of a power cylinder having a piston integrated with a rack that engages the steering shaft in the straight forward position of the switching valve are connected to the tank, and as the switching valve moves to each steering position, one of the cylinders is connected to the tank. The chamber is first isolated from the tank and sealed, and then connected to the hydraulic pressure source, or in the straight forward position, both the left and right chambers of the power cylinder are connected to the hydraulic pressure source, and as the power cylinder moves to each steering position, the other cylinder is connected to the hydraulic pressure source. In a power steering system for a vehicle of a closed center type in which a chamber of the power cylinder is isolated from a hydraulic pressure source and then connected to a tank, each chamber of the power cylinder is connected to the hydraulic pressure source or the tank connected at the straight-ahead position. In the case where the switching valve is connected through separate parallel passages, and each side passage connects each of the chambers and the tank, a one-way valve that allows oil to flow into each chamber is connected to each of the chambers. The one connected to the hydraulic pressure source is characterized in that a one-way valve is inserted in each chamber to allow oil to flow out from each chamber.

第２発明は、上記第１発明において更に路面抵
抗に応じた操向力の変化が得られるようにした装
置を提供することをその目的とするもので、前記
切換弁は直進位置においてパワシリンダの両室を
共にタンクに接続する型式のものに構成し、前記
各側路に、前記各一方向弁と前記各室との間にお
いて、前記切換弁の直進位置からの何れの切換移
動によつても体積を減少される油圧反動室を各介
入せしめたことを特徴とする。次いで本発明実施
の１例を第１図乃至第３図に付説明する。 A second aspect of the present invention is to provide a device in which, in addition to the first aspect, the steering force can be changed in accordance with road resistance, and the switching valve is configured to operate on both sides of the power cylinder in the straight-ahead position. The chambers are both connected to a tank, and each of the side passages is provided between each of the one-way valves and each of the chambers by any switching movement of the switching valve from the straight position. It is characterized by the intervention of a hydraulic reaction chamber whose volume is reduced. Next, an example of implementing the present invention will be explained with reference to FIGS. 1 to 3.

図面で１は車輌における操向軸、２はその根部
の操向ハンドルを示し、該操向軸１を前方に延長
して、該軸２の回動に伴われて回動する側方の斜
歯型のラツク３を咬合う斜歯型のピニオン４を有
するピニオン軸５と、該斜歯型のピニオン４の左
右の回動に際し、該ピニオン軸５に作用する前後
方向の反力により弁筐６内を中間の直進位置から
その前後の左右各操向位置に切換摺動される切換
弁７とを順次に形成した。 In the drawings, reference numeral 1 indicates a steering shaft of the vehicle, and 2 indicates a steering handle at the base of the vehicle. A pinion shaft 5 has a diagonal tooth-shaped pinion 4 that engages a tooth-shaped rack 3, and when the diagonal tooth-shaped pinion 4 rotates from side to side, a reaction force in the front and rear direction acting on the pinion shaft 5 causes the valve casing to move. Switching valves 7 which are slidably switched from an intermediate straight-ahead position to each of the left and right steering positions before and after the straight-ahead position are sequentially formed in the inside of the valve 6.

該切換弁７は、各操向位置において前記ラツク
３に連結されるピストン８を有するパワシリンダ
９の左右両室９ａ，９ｂの一方を、エンジンに連
動する油圧ポンプから成る作動油圧源１０に、他
方をタンク１１に選択的に接続し、直進位置にお
いて前記両室９ａ，９ｂを共にタンク１１に接続
して、該切換弁７を介しての作動油圧源１０とタ
ンク１１との接続を常時は断つクローズドセンタ
型に構成した。これを更に詳述すれば、該切換弁
７は、前記作動油圧源１０に連る弁筐６の給油ポ
ート６ａに常時連通する中間の第１環状溝７ａ
と、その前後の第２第３環状溝７ｂ，７ｃとを備
え、これら第２第３環状溝７ｂ，７ｃは互に透孔
１２，１２を介して連通させて、直進位置におい
てパワシリンダ９の左右各室９ａ，９ｂに連る第
１第２シリンダポート６ｂ，６ｃをこれら第２第
３環状溝７ｂ，７ｃを介してタンク１１に連るタ
ンクポート６ｄに連通させ、前記両室９ａ，９ｂ
を共にタンク１１に接続せしめるようにした。そ
して、該切換弁７の各操向位置への摺動によれ
ば、両シリンダポート６ｂ，６ｃの一方を第１環
状溝７ａを介して給油ポート６ａに切換接続し、
前記両室９ａ，９ｂの一方に作動油圧源１０から
の圧油を供給して、手動による操向に所定の動力
補助が与えられるようにした。更に、該切換弁７
の各操向位置への切換摺動に際し、給油ポート６
ａに切換接続される一方のシリンダポート６ｂ，
６ｃを介して該給油ポート６ａとタンクポート６
ｄとが接続されることのないように、該シリンダ
ポート６ｂ，６ｃは給油ポート６ａに接続される
以前にタンクポート６ｄとの接続を断ち、タンク
ポート６ｄから給油ポート６ａに切換接続される
迄の間密閉されるようにした。以上は上記した従
来式のものと特に異るところはないが、本発明に
よれば、前記パワシリンダ９の左右各室９ａ，９
ｂとタンク１１とを各別の第１第２側路１３，１
４を介して接続し、各側路１３，１４に各室９
ａ，９ｂへの油の流入を許す第１第２一方向弁１
５，１６を各介入した。各側路１３，１４は一端
において各室９ａ，９ｂに連る前記第１第２シリ
ンダポート６ｂ，６ｃに、他端においてタンク１
１に連る弁筐６の前端の室６ｅに各連通させるも
ので、各シリンダポート６ｂ，６ｃと各一方向弁
１５，１６との間に下記する第１第２油圧反動室
１７，１８を各介入した。 The switching valve 7 connects one of the left and right chambers 9a, 9b of a power cylinder 9 having a piston 8 connected to the rack 3 at each steering position to an operating hydraulic pressure source 10 consisting of a hydraulic pump linked to the engine, and the other is selectively connected to the tank 11, both chambers 9a and 9b are connected to the tank 11 in the straight forward position, and the connection between the hydraulic pressure source 10 and the tank 11 via the switching valve 7 is normally cut off. It is configured as a closed center type. To explain this in more detail, the switching valve 7 has an intermediate first annular groove 7a that is always in communication with the oil supply port 6a of the valve housing 6 connected to the hydraulic pressure source 10.
and second and third annular grooves 7b and 7c in front and rear thereof, and these second and third annular grooves 7b and 7c communicate with each other through through holes 12 and 12, so that the left and right sides of the power cylinder 9 are connected to each other in the straight-ahead position. The first and second cylinder ports 6b and 6c connected to the respective chambers 9a and 9b are communicated with the tank port 6d connected to the tank 11 via these second and third annular grooves 7b and 7c, and both the chambers 9a and 9b are connected to each other.
Both are connected to tank 11. Then, by sliding the switching valve 7 to each steering position, one of the cylinder ports 6b, 6c is switched and connected to the oil supply port 6a via the first annular groove 7a,
Pressure oil from a hydraulic pressure source 10 is supplied to one of the chambers 9a, 9b to provide a predetermined power assistance to manual steering. Furthermore, the switching valve 7
When switching to each steering position, the oil supply port 6
one cylinder port 6b, which is switch-connected to a;
The oil supply port 6a and tank port 6 are connected via 6c.
d, the cylinder ports 6b and 6c are disconnected from the tank port 6d before being connected to the refueling port 6a, and the cylinder ports 6b and 6c are disconnected from the tank port 6d until the tank port 6d is switched and connected to the refueling port 6a. It was kept sealed for a while. Although the above is not particularly different from the conventional type described above, according to the present invention, each of the left and right chambers 9a, 9 of the power cylinder 9
b and the tank 11 in separate first and second side passages 13 and 1.
4, and each side passage 13, 14 is connected to each chamber 9.
First and second one-way valves 1 that allow oil to flow into a and 9b
5 and 16 respectively. Each side passage 13, 14 has one end connected to the first and second cylinder ports 6b, 6c connected to each chamber 9a, 9b, and the other end connected to the tank 1.
1, and the following first and second hydraulic reaction chambers 17, 18 are provided between each cylinder port 6b, 6c and each one-way valve 15, 16. Each intervened.

即ち、これら油圧反動室１７，１８は、切換弁
７の側方にその直進位置からの何れの切換移動に
よつても体積を減少されるべく設けるもので、各
油圧反動室１７，１８内にはばね１９で互に弾発
される前後１対のプランジヤ２０，２０を設け、
該プランジヤ２０，２０は切換弁７に突設した前
後１対のフランジ２１，２１間に挾持させて、常
時は切換弁７を直進位置に保持せしめるべく作用
するようにした。尚、前記一方向弁１５，１６は
各油圧反動室１７，１８の前方のプランジヤ２
０，２０に一体に配設した。２２，２３は、第１
第２油圧反動室１７，１８に切換弁７を介して各
対向すべく設けた副油圧反動室で、夫々通路２
４，２５を介して前記第１第２シリンダポート６
ｂ，６ｃに連通した。 That is, these hydraulic reaction chambers 17 and 18 are provided on the side of the switching valve 7 so that the volume can be reduced by any switching movement from the straight forward position. A pair of front and rear plungers 20, 20 are provided, which are urged against each other by a leaf spring 19.
The plungers 20, 20 are sandwiched between a pair of front and rear flanges 21, 21 protruding from the switching valve 7, and normally act to maintain the switching valve 7 in the straight forward position. The one-way valves 15 and 16 are connected to the plunger 2 in front of each hydraulic reaction chamber 17 and 18.
0 and 20. 22 and 23 are the first
The secondary hydraulic reaction chambers are provided to face the second hydraulic reaction chambers 17 and 18 via the switching valve 7, and each passage 2
4, 25 to the first and second cylinder ports 6
It communicated with b and 6c.

２６は、前記作動油圧源１０と供給ポート６ａ
とを結ぶ給油路１０ａに介在させた蓄圧器を示
す。次いでその作動を説明するに、操向軸１を例
えば左方に回動すると、ラツク３とこれに連結さ
れるピストン８が右方に移動し、切換弁７がピニ
オン軸５に作用する前方への反力により前記油圧
反動室１７，１８，２２，２３のばね１９に抗し
て前方に切換摺動し、上記の如くパワシリンダ９
の左室９ａに連る第１シリンダポート６ｂが第１
環状溝７ａを介して給油ポート６ａに切換接続さ
れて、該左室９ａに作動油圧源１０からの圧油が
供給されて動力補助が行なわれる。この切換摺動
に際し、第１シリンダポート６ｂ従つて左室９ａ
は、上記の如くタンクポート６ｄとの接続を断た
れて、その後給油ポート６ａに接続される迄密閉
され、その間もピストン８は右動を続けて負圧と
なるが、かくするときは前記第１側路１３に介在
させた第１一方向弁１５が開いて、該左室９ａに
タンク１１からの油が流入され、一定圧以上の負
圧になることを防止されて、該室９ａ内の油に気
泡の発生を来たすことはない。 26 is the hydraulic pressure source 10 and the supply port 6a.
A pressure accumulator is shown interposed in the oil supply path 10a connecting the two. Next, to explain its operation, when the steering shaft 1 is rotated, for example, to the left, the rack 3 and the piston 8 connected thereto move to the right, and the switching valve 7 moves forward where it acts on the pinion shaft 5. The reaction force causes the hydraulic reaction chambers 17, 18, 22, and 23 to switch and slide forward against the springs 19, and as described above, the power cylinder 9
The first cylinder port 6b connected to the left chamber 9a of the
The left chamber 9a is switchably connected to the oil supply port 6a via the annular groove 7a, and pressurized oil from the hydraulic pressure source 10 is supplied to the left chamber 9a to provide power assistance. During this switching sliding, the first cylinder port 6b and the left chamber 9a
As described above, the connection with the tank port 6d is cut off, and the piston 8 is sealed until it is connected to the refueling port 6a. During this time, the piston 8 continues to move to the right and becomes a negative pressure. The first one-way valve 15 interposed in the first side passage 13 opens, and oil from the tank 11 flows into the left chamber 9a, preventing the negative pressure from becoming more than a certain pressure, and causing the inside of the chamber 9a to flow. It does not cause bubbles to form in the oil.

そして、動力補助時には、該左室９ａ内の油圧
が路面抵抗に応じて増大し、該油圧は第１側路１
３に介在させた第１油圧反動室１７とその副油圧
反動室２２とに作用して、前記ばね１９の弾発力
をその分強める結果となり、切換弁７を前方の操
向位置に保持せしめる力従つて操向力は路面抵抗
に応じて変化する。 At the time of power assistance, the hydraulic pressure in the left chamber 9a increases according to the road resistance, and the hydraulic pressure increases in the first side passage 1.
3 acts on the first hydraulic reaction chamber 17 and its auxiliary hydraulic reaction chamber 22, thereby increasing the elastic force of the spring 19 accordingly, thereby holding the switching valve 7 in the forward steering position. The steering force and therefore the steering force change depending on the road resistance.

以上は操向軸１を左方に回動した場合である
が、これを右方に回動した場合においても、第２
側路１４と第２一方向弁１６と第２油圧反動室１
８とその副油圧反動室２３により同様の作動が行
なわれる。尚、上記第１第２油圧反動室１７，１
８は各側路１３，１４に介入させなくとも良いの
であるが、かくするときは側路１３，１４の他に
これら油圧反動室１７，１８をパワシリンダ９の
両室９ａ，９ｂに各別に連通する通路を形成する
必要があつて、当該装置が複雑となる。 The above is a case where the steering shaft 1 is rotated to the left, but even when it is rotated to the right, the second
Side passage 14, second one-way valve 16, and second hydraulic reaction chamber 1
8 and its auxiliary hydraulic reaction chamber 23 perform similar operations. Note that the first and second hydraulic reaction chambers 17, 1
8 does not need to intervene in each of the side passages 13 and 14, but in this case, in addition to the side passages 13 and 14, these hydraulic reaction chambers 17 and 18 are connected to both chambers 9a and 9b of the power cylinder 9 separately. This makes the device complicated.

第４図は他の実施例を示すもので、上記実施例
と特に異るところは、切換弁７を直進位置におい
てパワシリンダ９の両室９ａ，９ｂを共に作動油
圧源１０に接続する型式のものに構成し、第１第
２側路１３，１４をパワシリンダ９の各室９ａ，
９ｂに連る第１第２シリンダポート６ｂ，６ｃと
作動油圧源１０に連る給油路１０ａとの間に切換
弁７と並列に設け、これら各側路１３，１４に介
入される一方向弁１５，１６を前記各室９ａ，９
ｂからの油の流出を許す型式に構成した点であ
る。又、上記実施例の油圧反動室１７，１８，２
２，２３と同様にプランジヤ２０，２０とばね１
９とを有する反動室２７，２８，２９，３０を設
けたが、これらは前記側路１３，１４に介入させ
ず、タンク１１に常時連通させるもので、ばね１
９の弾発力により常時切換弁７を直進位置に保持
せしめるべく作用するが、上記実施例の油圧反動
室１７，１８，２２，２３のように操向力を路面
抵抗に応じて変化させるような作用はしない。 FIG. 4 shows another embodiment, which differs from the above embodiment in that the switching valve 7 is in the straight forward position and both chambers 9a and 9b of the power cylinder 9 are connected to the hydraulic pressure source 10. The first and second side passages 13 and 14 are connected to each chamber 9a of the power cylinder 9,
A one-way valve is provided in parallel with the switching valve 7 between the first and second cylinder ports 6b, 6c connected to the hydraulic pressure source 9b and the oil supply path 10a connected to the hydraulic pressure source 10, and intervened in each of these side paths 13, 14. 15 and 16 in each of the chambers 9a and 9.
The point is that it is constructed in a type that allows oil to flow out from b. Moreover, the hydraulic reaction chambers 17, 18, 2 of the above embodiment
Similar to 2 and 23, plungers 20 and 20 and spring 1
Although reaction chambers 27, 28, 29, and 30 having a spring 1 and a
Although the switching valve 7 is always maintained in the straight-ahead position by the elastic force of the spring 9, the steering force is changed in accordance with the road resistance like the hydraulic reaction chambers 17, 18, 22, and 23 of the above embodiment. It has no effect.

次いでその作動を説明するに、切換弁７を各操
向位置に移動せしめれば、パワシリンダ９の両室
９ａ，９ｂの一方が作動油圧源１０に接続状態に
維持されたまま他方がタンク１１に切換接続され
て、手動の操向に所定の動力補助が与えられる。
この切換摺動に際し、該他方の室９ａ，９ｂは、
先ず作動油圧源１０との接続を断たれて、その後
タンク１１に接続される迄は密閉状態に存するよ
うにするから、その間も移動を続けるピストン８
により圧縮されて高圧となるが、該他方の室９
ａ，９ｂ内の油は、これに連る側路１３，１４の
一方向弁１５，１６を開いて給油路１０ａに流出
し、一定圧以上には上昇せず操向力の増大を来た
すことはない。 Next, to explain its operation, when the switching valve 7 is moved to each steering position, one of the chambers 9a, 9b of the power cylinder 9 is maintained connected to the hydraulic pressure source 10, and the other is connected to the tank 11. A switching connection is made to provide a predetermined power assistance to manual steering.
During this switching sliding, the other chambers 9a and 9b are
First, the connection with the hydraulic pressure source 10 is cut off, and then the piston 8 is kept in a sealed state until it is connected to the tank 11, so that the piston 8 continues to move during that time.
The other chamber 9 is compressed and becomes high pressure.
The oil in a and 9b opens the one-way valves 15 and 16 of the side passages 13 and 14 connected thereto and flows out into the oil supply passage 10a, and does not rise above a certain pressure and causes an increase in steering force. There isn't.

尚、上記両実施例においては、切換弁７として
摺動式のものを用いたが、これに限るものではな
く回動式のものを用いても良い。 In both of the above embodiments, a sliding type switching valve 7 is used, but the switching valve 7 is not limited to this, and a rotating type may also be used.

この様に本発明によるときは、切換弁としてク
ローズドセンタ型のものを用いても、一方向弁を
介入した側路を介してパワシリンダの室内の圧力
が調整されて、該室内の油に気泡の発生を来たし
たり又圧縮を与えられて操向力が増大するといつ
た上記従来式の不都合を生ずることがなく、更に
第２発明によれば操向力を路面抵抗に応じて変化
させることが出来て、而も構造簡単な装置が得ら
れる等の効果を有する。 As described above, according to the present invention, even if a closed center type switching valve is used, the pressure inside the power cylinder chamber is regulated through the side path with a one-way valve, and air bubbles are prevented from entering the oil inside the chamber. The above-mentioned disadvantages of the conventional method, such as the steering force increasing due to compression or compression, do not occur, and furthermore, according to the second invention, the steering force can be changed in accordance with the road resistance. This has the advantage that a device with a simple structure can be obtained.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明装置の１例の截断側面図、第２
図は第１図の―線截断面図、第３図はその油
圧回路を示す線図、第４図は他の実施例の油圧回
路を示す線図である。 １……操向軸、７……切換弁、９……パワシリ
ンダ、９ａ，９ｂ……左右各室、１０……作動油
圧源、１１……タンク、１３，１４……側路、１
５，１６……一方向弁、１７，１８……油圧反動
室。 Fig. 1 is a cutaway side view of one example of the device of the present invention;
The drawings are a sectional view taken along the line -- in FIG. 1, FIG. 3 is a diagram showing the hydraulic circuit, and FIG. 4 is a diagram showing the hydraulic circuit of another embodiment. 1...Steering shaft, 7...Switching valve, 9...Power cylinder, 9a, 9b...Right and left chambers, 10...Operating oil pressure source, 11...Tank, 13, 14...Side passage, 1
5, 16... One-way valve, 17, 18... Hydraulic reaction chamber.

Claims (1)

【特許請求の範囲】 １ 操向軸の回動に伴い直進位置と左右各操向位
置との３位置に切換移動される切換弁を備え、該
切換弁の直進位置において操向軸に咬うラツクと
一体のピストンを有するパワシリンダの左右両室
を共にタンクに接続して各操向位置への切換移動
に伴い前記シリンダの一方の室を先づタンクから
遮断して密封状態とし次いで作動油圧源に接続又
は直進位置において前記パワシリンダの左右両室
を共に作動油圧源に接続して各操向位置への切換
移動に伴い前記シリンダの他方の室を作動油圧源
から遮断して次いでタンクに接続するクローズド
センタ型の車両の動力操向装置において、前記パ
ワシリンダの各室と、前記直進位置において接続
される前記作動油圧源又はタンクとを前記切換弁
に並列の各別の側路を介して接続し、各側路に前
記各室とタンクとを接続するものでは各室への油
の流入を許す一方向弁を、前記各室と作動油圧源
とを接続するものでは各室からの油の流出を許す
一方向弁を各介入せしめたことを特徴とする車両
の動力操向装置。 ２ 操向軸の回動に伴い直進位置と左右各操向位
置との３位置に切換移動される切換弁を備え、該
切換弁の直進位置において操向軸に咬うラツクと
一体のピストンを有するパワシリンダの左右両室
を共にタンクに接続して各操向位置への切換移動
に伴い前記シリンダの一方の室を先づタンクから
遮断して密封状態とし次いで作動油圧源に接続し
て、該切換弁を介して作動油圧源とタンクとの接
続を常時は断つクローズドセンタ型に構成させ、
前記パワシリンダの各室とタンクとを前記切換弁
に並列の各別の側路を介して接続し各側路に、前
記各室への油の流入を許す一方向弁を各介入せし
める車両の動力操向装置において、これら各側路
に前記各一方向弁と前記各室との間において前記
切換弁の直進位置から何れの切換移動によつても
体積を減少される油圧反動室を介入せしめたこと
を特徴とする車両の動力操向装置。[Scope of Claims] 1. A switching valve that is switched between three positions, a straight-ahead position and left and right steering positions as the steering shaft rotates, and that engages the steering shaft in the straight-ahead position of the switching valve. Both the left and right chambers of a power cylinder having a piston integrated with the rack are connected to the tank, and when switching to each steering position, one chamber of the cylinder is first shut off from the tank to seal it, and then the hydraulic pressure is supplied. or connect both the left and right chambers of the power cylinder to the hydraulic pressure source in the straight-ahead position, cut off the other chamber of the cylinder from the hydraulic pressure source as it switches to each steering position, and then connect it to the tank. In a power steering system for a closed center vehicle, each chamber of the power cylinder is connected to the hydraulic pressure source or tank connected at the straight-ahead position through separate side passages parallel to the switching valve. However, the one-way valve that connects each of the above-mentioned chambers and the tank to each side passage allows oil to flow into each chamber, and the one-way valve that connects each of the above-mentioned chambers to the hydraulic pressure source has a one-way valve that allows oil to flow from each chamber. A power steering system for a vehicle, characterized in that a one-way valve for allowing outflow is provided in each of the valves. 2.Equipped with a switching valve that can be switched between three positions, a straight-ahead position and left and right steering positions, as the steering shaft rotates, and a piston integrated with a rack that engages the steering shaft in the straight-ahead position of the switching valve. Both the left and right chambers of the power cylinder having the power cylinder are connected to the tank, and as the cylinder is switched to each steering position, one chamber of the cylinder is first shut off from the tank to be in a sealed state, and then connected to the hydraulic pressure source. It is configured as a closed center type that normally disconnects the hydraulic pressure source and tank via a switching valve.
Each chamber of the power cylinder and the tank are connected through separate side passages in parallel with the switching valve, and each side passage is provided with a one-way valve that allows oil to flow into each of the chambers. In the steering device, a hydraulic reaction chamber whose volume is reduced by any switching movement of the switching valve from the straight forward position is interposed between each of the one-way valves and each of the chambers in each of these side passages. A vehicle power steering device characterized by: