JP2543401B2 - Hydraulic suspension - Google Patents

Description

TECHNICAL FIELD The present invention relates to a suspension of a vehicle such as an automobile,
More particularly, it relates to a hydraulic suspension.

2. Description of the Related Art Conventionally, a fluid pressure suspension of a vehicle such as an automobile has generally been provided with a working fluid supply passage, a working fluid discharge passage,
A fluid pressure actuator provided between the wheel and the vehicle body, a connection passage communicating with the actuator, and a connection passage by selectively connecting the connection passage with the working fluid supply passage means or the working fluid discharge passage. A pressure control valve for controlling the pressure in the actuator via the pressure control valve.

In such a fluid pressure type suspension, when severely and rapidly turning or accelerating or decelerating, the pressure in the actuator and the accumulator for the gas spring communicating with this becomes very high. It is necessary to. In order to achieve such an object, for example, as described in Japanese Utility Model Application Laid-Open No. 63-81707, a return passage that connects the connection passage and the working fluid discharge passage to each other and a connection passage provided in the middle of the return passage Conventionally, a relief valve that opens when the pressure exceeds a predetermined value is provided, and when the pressure in the connection passage exceeds a predetermined value, the relief valve opens and part of the working fluid in the connection passage goes to the discharge passage. It is supposed to be discharged.

In such a conventional fluid pressure type suspension, when the pressure in the connection passage exceeds a predetermined value, the relief valve is opened and a part of the working fluid in the connection passage is discharged. Therefore, the energy of the high-pressure working fluid is wasted, resulting in a deterioration of fuel efficiency.

If the pressure in the connection passage exceeds the upper limit of the control pressure range of the pressure control valve even if the pressure does not rise to the opening pressure of the relief valve, the pressure control valve connects the connection passage and the working fluid discharge passage, As a result, a part of the working fluid in the connection passage is discharged to the working fluid discharge passage via the pressure control valve.
Therefore, when the vehicle turns or accelerates / decelerates relatively rapidly, the roll of the vehicle body increases relatively rapidly when the pressure in the connection passage exceeds the upper limit of the control pressure range of the pressure control valve. There's a problem.

In view of the above-mentioned problems in the conventional fluid pressure type suspension, the present invention can prevent the pressure in the actuator from becoming excessive without wasting energy, and can prevent relatively sharp turning and An improved fluid pressure system that prevents the roll of the vehicle body from increasing relatively rapidly even when the pressure in the connection passage reaches the upper limit of the control pressure range of the pressure control valve due to acceleration / deceleration. Intended to provide suspension.

According to the present invention, a working fluid supply passage having an accumulator, a working fluid discharge passage, a fluid pressure actuator arranged between a wheel and a vehicle body,
Pressure control for controlling the pressure in the actuator via the connection passage by selectively connecting the connection passage communicating with the actuator and the working fluid supply passage or the working fluid discharge passage with the connection passage. A fluid having a valve and relief means for connecting the connection passage and the working fluid supply passage in communication when the pressure in the connection passage exceeds a predetermined value to guide the working fluid from the connection passage to the working fluid supply passage. Achieved by pressure suspension.

According to the above-mentioned structure, when the pressure in the connection passage exceeds a predetermined value, the connection passage and the working fluid supply passage are connected to each other to guide the working fluid from the connection passage to the working fluid supply passage. Since the means is provided, when the pressure in the actuator becomes extremely high due to rapid turning or acceleration / deceleration and the pressure in the connection passage exceeds a predetermined value, a part of the working fluid in the connection passage is removed. It is possible to prevent the pressure in the actuator from becoming excessive while effectively recovering the energy held in the high-pressure working fluid by being guided to the working fluid supply passage and the accumulator instead of the working fluid discharge passage.

In the structure as described above, the pressure in the connection passage where the relief means starts to function, that is, the predetermined value is substantially equal to or slightly lower than the upper limit value of the control pressure range of the pressure control valve. When the pressure in the connection passage exceeds a predetermined value, the connection passage and the working fluid supply passage are connected to each other, so that the pressure control valve connects the connection passage and the working fluid discharge passage. This prevents a part of the working fluid in the connection passage from being discharged to the working fluid discharge passage, which prevents the pressure in the connection passage even when the vehicle makes a relatively rapid turn or acceleration / deceleration. It is possible to reliably prevent the roll of the vehicle body and the like from increasing relatively rapidly when the pressure exceeds the upper limit of the control pressure range of the pressure control valve.

According to one embodiment of the present invention, the relief means is provided with a return passage connecting the connection passage and the working fluid supply passage, and opened when the pressure in the connection passage exceeds a predetermined value. The relief valve and the check valve provided in the middle of the return passage and permitting only the flow of the working fluid from the connection passage to the working fluid supply passage. The relief valve and the check valve are configured as one valve. It is preferable.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Embodiment FIG. 1 is a schematic configuration diagram showing one embodiment of a fluid pressure type suspension according to the present invention.

In the figure, reference numeral 10 denotes a reserve tank that stores oil as a working fluid, and the reserve tank is a flow path 12
Is connected to the pump 14. One end of a working fluid supply passage 16 is connected to the pump 14, whereby the pump 14 pumps up the working fluid from the reserve tank 10 through the flow path 12 and supplies the high-pressure working fluid to the working fluid supply passage 16. It has become. The other end of the working fluid supply passage 16 is connected to the pressure control valve 18.

An attenuator 20 that absorbs the pressure pulsation of the working fluid discharged from the pump and reduces the pressure change in the middle of the working fluid supply passage 16 and a check valve that allows only the working fluid flow from the pump to the pressure control valve 18. 22 are provided. An accumulator 24 is connected to the working fluid supply passage 16 at a position downstream of the check valve 22. The accumulator absorbs pressure pulsation of the working fluid by enclosing high pressure gas therein, and accumulates pressure. It is designed to

A portion of the working fluid supply passage 16 between the attenuator 20 and the check valve 22 is communicatively connected by a passage 26 to a working fluid discharge passage 28 that communicates with the reserve tank 10 at one end. A relief valve 30 is provided in the middle of the passage 26, and the relief valve is opened when the pressure of the working fluid in the working fluid supply passage 16 is equal to or higher than a predetermined value so that the working fluid in the working fluid supply passage 16 is protected. A part of the fluid is guided to the working fluid discharge passage 28, thereby preventing the pressure of the working fluid in the working fluid supply passage 16 from rising above a predetermined value.

A portion of the working fluid supply passage 16 on the downstream side of the check valve 22 is connected to a working fluid discharge passage 28 through passages 32 and 34. In the middle of the passage 32, a throttle 36 and a normally open type solenoid valve 38 with adjustable flow rate are provided. Solenoid open / close valve 38
Is capable of adjusting the flow rate of the working fluid passing through the valve by changing the exciting current supplied to the solenoid 40 and closing the valve as required. A pilot operated on-off valve 42 is provided in the middle of the passage 34. The on-off valve 42 takes in the pressure on both sides of the throttle 36 as pilot pressure and maintains the valve closed position 42a when there is no differential pressure on both sides of the throttle 36, and the pressure on the upstream side of the throttle 36, that is, the working fluid supply passage side is high. Sometimes, it is switched to the valve opening position 42b. Thus throttle 36, solenoid on-off valve 3
8 and the on-off valve 42 cooperate with each other to provide the working fluid supply passage 16
The bypass valve 44 for controlling the pressure in the working fluid supply passage 16 is configured by selectively connecting the working fluid discharge passage 28 and the working fluid discharge passage 28.

As shown in the figure, the pressure control valve 18 includes a switching control valve 46, a passage 48 for connecting the working fluid supply passage 16 and the working fluid discharge passage 28 to each other, a fixed throttle 50 and a variable throttle 52 provided in the middle of the passage. It has become. The other end of the working fluid supply passage 16 is connected to the P port of the switching control valve 46, the other end of the working fluid discharge passage 28 is connected to the R port, and one end of the connection passage 54 is connected to the A port. ing.

The switching control valve 46 is a spool valve that takes in the pressure Pp in the passage 48 between the fixed throttle 50 and the variable throttle 52 and the pressure Pa in the connection passage 54 as pilot pressure, and the pressure Pp and the spring force F of the spring 47. When the sum of the pressure and pressure is higher than Pa, the pressure is changed to the switching position 46a where the P port and A port are connected for communication.
When the sum of p and the spring force F and Pa are substantially equal to each other, the port is switched to the switching position 46b that shuts off the communication of all ports, and when the sum of the pressure Pp and the spring force F is lower than the pressure Pa, the port R And the port A are connected to each other so as to switch to a switching position 46c. Further, the variable throttle 52 changes the effective passage cross-sectional area of the throttle by controlling the current supplied to its solenoid 56, and thereby changes the pressure Pp in cooperation with the fixed throttle 50.

The other end of the connection passage 54 is connected to the actuator 58. In the illustrated embodiment, the actuator 58 comprises a cylinder 60 and a piston 64 which fits in the cylinder and cooperates with the cylinder to define a working fluid chamber 62, the cylinder being shown in the figure. It is connected to a suspension arm that is not mounted, and is connected to a vehicle body (not shown) at the tip of the rod portion of the piston. Further, a suspension spring 70 is mounted between the upper seat 66 fixed to the rod portion of the piston and the lower seat 68 fixed to the cylinder. As shown, the piston 64 is provided with a passage 72, one end of which communicates with the working fluid chamber 62 and the other end of which communicates with the other end of the connection passage 54. An accumulator 76 for a gas spring is connected to the working fluid chamber 62 via a throttle 74.

Further, the connection passage 54 and the working fluid supply passage 16 are connected to each other by a return passage 78, and a relief valve 80 is provided in the middle of the return passage. Relief valve
On the other hand, 80 takes in the pressure in the return passage 78 on the side of the connection passage 54, therefore, the pressure Pa in the connection passage 54 as a pilot pressure, and when the pressure exceeds a predetermined set pressure Pr, it opens to open from the connection passage 54. The working fluid is allowed to flow toward the working fluid supply passage 16. Thus the return passage 78
The relief valve 80 cooperates with each other to form a relief device 82 that guides a part of the working fluid in the connection passage 54 to the working fluid supply passage 16 when the pressure Pa exceeds the set pressure Pr.

In this case, the set pressure Pr of the relief valve 80 is preferably substantially equal to or less than the upper limit value Ph of the control pressure range of the pressure control valve 18, and in the illustrated embodiment, the set pressure Pr is the upper limit. It is set to a value substantially the same as the value Ph.

Although not shown in the figure, the pressure control valve 18, the connection passage 54, the actuator 58, the relief device 82, etc. are provided corresponding to each wheel of the vehicle.

Therefore, according to this embodiment, the pressure Pa in the working fluid chamber 62 of the actuator 58 is set to the set pressure of the relief valve 80 by the vehicle not shown in the drawing performing severe turning and acceleration / deceleration.
When Pr is exceeded, the relief valve 80 opens and part of the working fluid in the connection passage 54 is returned to the working fluid supply passage 16 through the return passage 78, whereby the energy held by the high-pressure working fluid is effective. Will be collected.

Further, since the connection passage 54 and the high pressure passage 16 are communicatively connected when the pressure Pa exceeds the set pressure Pr, the connection passage 54 and the working fluid discharge passage 28 are communicatively connected by the switching control valve 46 of the pressure control valve 18. As a result, a relatively large amount of working fluid in the connection passage is prevented from being discharged to the working fluid discharge passage,
As a result, even when the vehicle makes a relatively rapid turn or acceleration / deceleration, when the pressure in the working fluid chamber 62 exceeds the upper limit value Ph of the control pressure range of the pressure control valve, the roll of the vehicle body, etc. becomes relatively abrupt. Is certainly avoided.

FIG. 2 is a schematic diagram similar to FIG. 1 showing another embodiment of the fluid pressure suspension according to the present invention.
Note that, in FIG. 2, the same reference numerals as those in FIG. 1 are attached to the substantially same portions as those shown in FIG.

In this embodiment, the relief valve 80 has a pressure Pa in the connection passage 54 and a pressure in the return passage 78 on the working fluid supply passage 16 side with respect to the relief valve 80, and thus a pressure Ps in the working fluid supply passage 16. The valve is configured to open when the pressure difference (Pa-Ps) between and exceeds the set pressure Pr.

Therefore, according to this embodiment, the pressure Pa in the working fluid chamber 62 is
The relief valve 80 opens when the differential pressure Pa-Ps exceeds the set value Pr due to the rise of the pressure difference. Thus, the same effect as that of the embodiment shown in FIG. 1 can be obtained.

According to this embodiment, the relief valve 80 has a differential pressure Pa-Ps.
Is opened when the pressure exceeds the set pressure Pr, the working fluid is frequently supplied to and discharged from the actuator 58 by the pressure control valve 18 in order to control the riding comfort and the posture of the vehicle. When the pressure Pa in the working fluid supply passage 16 decreases, the pilot pressure Pp also decreases, which facilitates switching of the switching control valve 46 to the switching position 46c. According to this embodiment, the relief valve 80 has a differential pressure Pa. -When Ps exceeds the set pressure Pr, the valve opens so that the pressure in the working fluid chamber 62 is increased by sudden turning or acceleration / deceleration of the vehicle while the pressure in the working fluid supply passage is reduced. Even when the pressure suddenly rises, the switching control valve 46 can be prevented from switching to the switching position 46c, and at a stage where the pressure Pa is lower than that in the embodiment shown in FIG. Relief valve 80 has opened, which is shown in FIG. It is possible to improve the recovery of energy than in the case of 施例.

In the suspension of the present invention, the application of the present application was filed on the same date as the present application so that the working fluid can be more reliably guided from the connection passage to the working fluid supply passage when the pressure in the connection passage exceeds a predetermined value. The working fluid discharge inhibiting means described in Japanese Patent Application No. 63-335553 filed by the same applicant as the person is between the portion of the connection passage 54 to which the return passage 78 is connected or the pressure control valve 18 or the working fluid. It may be provided in the middle of the discharge passage. Further, an orifice may be provided in the middle of the pilot passage on the upper side of the switching control valve 46 in the drawing.

In the above, the present invention has been described in detail with respect to two embodiments, but the present invention is not limited to these embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

[Brief description of drawings]

1 and 2 are schematic configuration diagrams showing one embodiment of a fluid pressure suspension according to the present invention. 10 …… Reserve tank, 12 …… Passage, 14 …… Pump, 16…
Working fluid supply passage, 18 Pressure control valve, 20 Attenuator, 22 Check valve, 24 Accumulator, 26 passage, 28 Working fluid discharge passage, 30 Relief valve, 32 , 34
...... Passage, 36 ...... Throttle, 38 ...... Solenoid on-off valve, 40 ...... Solenoid, 42 ...... Open / close valve, 44 ...... Bypass valve, 46 ...... Switching control valve, 48 ...... Passage, 50 ...... Fixed throttle , 52 ... Variable diaphragm, 54 ...
… Connection path, 56 …… Solenoid, 58 …… Actuator, 6
0 …… Cylinder, 62 …… Working fluid chamber, 64 …… Piston, 66…
… Upper seat, 68 …… Lower seat, 70 …… Suspension spring, 72 …… Passage, 74 …… Throttle, 76 …… Accumulator, 78 …… Return passage, 80 …… Relief valve, 82 ……
Relief device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Takeuma 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Takashi Yonekawa 1, Toyota Town, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Katsuhiko Hattori, 1 in 41 Chuo-dori, Nagakute-cho, Aichi-gun, Aichi-gun, Toyota Central Research Institute Co., Ltd. (72) Inventor, Osamu Komazawa, 2-chome, Asahi-cho, Kariya city, Aichi Prefecture (72) Inventor Narutaka Isoya, 2-1, Asahi-cho, Kariya city, Aichi Prefecture, Aisin Seiki Co., Ltd. (72) Inventor, Kenji Hayashi, 2--1, Asahi-machi, Kariya city, Aichi Prefecture, Aisin Seiki Co., Ltd. (56) Reference References JP-A 2-147424 (JP, A) JP-A 60-213513 (JP, A) Actual development Shou 63-81707 (JP, U)

Claims (1)

(57) [Claims] 1. A working fluid supply passage having an accumulator, a working fluid discharge passage, a fluid pressure actuator disposed between a wheel and a vehicle body, a connection passage communicating with the actuator, and the working fluid supply passage. Alternatively, a pressure control valve for controlling the pressure in the actuator via the connection passage by selectively connecting the working fluid discharge passage and the connection passage to each other, and the pressure in the connection passage exceed a predetermined value. And a relief means for connecting the connection passage and the working fluid supply passage in communication with each other to guide the working fluid from the connection passage to the working fluid supply passage.