JPH0628969B2 - Hydraulic telescopic actuator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic telescopic actuator suitable for use in a vehicle suspension such as disclosed in US Pat. No. 3,277,840, and more particularly to reducing its overall length. For this reason, the present invention relates to an actuator of a type having a cylindrical cylinder tube shape.

(Technical background) The double-acting hydraulic expansion / contraction actuator used in the vehicle suspension is designed to be nested, and tilts the vehicle sideways to the selected roll angle to stabilize the vehicle speed and road curvature over a wide range. It enables curved turn. Such an actuator not only maintains a stable turn of the vehicle at various vehicle operating speeds, but also responds quickly and instantaneously to a steering command, depending on a suitable control device, to change the roll angle of the vehicle to one roll angle. The angle is changed to another angle, and when the vehicle runs straight or stops, it has the ability to stand up.

As this kind of hydraulic expansion / contraction actuator, for example, the one disclosed in the above-mentioned US Pat. No. 3277840 is known, but in order to use it as a vehicle suspension, its setting space is limited, so it is smaller. Things were desired.

(Object of the Invention) The object of the present invention is set in relation to each wheel of a vehicle, and is used for controlling suspension load and displacement such as tilting the vehicle using power, and for damping vertical movement of the vehicle. A new and improved compact double-acting hydraulic telescopic actuator for use is provided.

(Structure of the Invention) In the hydraulic expansion / contraction actuator according to the present invention, the piston rod means is connected to the reciprocating piston, and extends from the connecting portion through the rod guide to be connected to the vehicle support structure. And a pair of variable volume chambers of hydraulic fluid are supplied to one or the other of the variable volume chambers to expand the respective chambers, thereby extending or retracting the piston rod means, respectively. A hydraulic telescopic actuator for an active suspension system connecting support structures, wherein concentric inner and outer cylinder tubes form a nested cylinder tube assembly and define a cylindrical cavity between both cylinders. , A piston is mounted for reciprocal movement in the cylindrical cavity, and A stone rod guide is secured to the upper end of the outer cylinder tube, the piston rod means is connected to the piston and extends upwardly through the rod guide to connect to a vehicle support structure, the piston being The first variable volume chamber is provided with an annular inner seal for sealingly contacting the contact portion with the inner cylinder tube and an annular outer seal for sealingly contacting the contact portion with the outer cylinder tube, The piston rod means is provided above the piston, and the piston rod means has a hydraulic flow path communicating with the first variable volume chamber, and the control means supplies pressurized hydraulic fluid to the first chamber. Adapted to expand the chamber and thus contract the actuator, wherein the piston rod means is adapted to the inner cylinder tube. Re mounted for child motion, and a second variable volume chamber is defined by the sealing contact portion between the piston and the inner cylinder tube,
The control means supplies pressurized fluid to the second chamber to expand the second chamber, and thereby expands the actuator.

(Operation and Effect of the Invention) In the actuator according to the present invention, the actuator can be expanded and contracted by introducing and discharging the hydraulic pressure into the first and second hydraulic chambers. Since the second hydraulic chambers are constructed as described above by using the interlocking cylinder tube assembly, they can be set concentrically with each other, and the total length thereof can be shortened as compared with the conventional one. Further, since the actuator according to the present invention has the above-mentioned structure, the air spring chamber separate from the hydraulic chamber can be formed in the actuator without increasing the total length thereof. Therefore,
It is not necessary to support the static load in the hydraulic part, and the power consumption can be greatly reduced. Further, even if the hydraulic portion is damaged, the air spring portion can support the load and can exert a suspension effect, and therefore, the vehicle can be driven at a low speed without stopping. Therefore, it is not necessary to provide other mechanical spring means such as a coil spring for that purpose.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the accompanying drawings.

Illustrated in FIGS. 1 and 2 is a vehicle double-acting active suspension unit 10 designed to replace the conventional struts known as MacPherson suspension struts. The suspension unit 10 includes an outer cylinder tube 12, an inner cylinder tube 14, and a base cylinder 16 connected to the lower ends of the inner cylinder tube 14 and a base cap 16 connected to each other.
d cylinder tube assembly) is used. As shown in FIG. 3, such a unit 10 is adapted to connect to a vehicle wheel assembly 17. The above-described configuration of the suspension 10 can shorten the length of the unit and maximize the use of space, and these units can be easily used instead of the conventional strut-shaped ones, and selectively. It is possible to extend and adjust the inclination of the vehicle.

A piston assembly 18 is attached to each suspension unit 10 so as to reciprocate relative to the cylinder tube assemblies 12, 14, and concentric inner and outer annular piston rods 22, 24 are provided. Each lower end is connected to a cylindrical piston 26. The concentric piston rods 22 and 24 have an oil passage between them.
27, which extends upwards through a cylindrical rod guide 28 and reaches the inside of a connector block 30. The rod guide is provided with an annular seal 31 for allowing the outer piston rod 24 to slide on the guide portion while maintaining a sealed state. The nut 32 is screwed to the upper end of the piston rod 24,
2, 24 are fixed to the connector block 30 and the vehicle body. This vehicle body portion is a conventional mounting tower 34 that is sandwiched between the lower side surface 35 of the connector block 30 and the upper shoulder portion 36 of the outer piston rod 24. Is part of. In this way, the vehicle body is firmly connected to the piston of the suspension unit 10 and moves with the movement of the piston.

Piston 26 has outer and inner cylinder tubes 12,
Mounted so as to reciprocate in a cylindrical space between 14 and inner and outer O-ring seals 4
0, 42 are provided to seal the cylinder-shaped cavity in an oil-tight and air-tight manner to form an upper chamber and a lower chamber 44, 46 that can be expanded and contracted. The upper chamber 44 is an oil chamber, and basically, pressurized oil is supplied from the control device 48 to the oil chamber as shown in FIG. 3, but in the control device, A separate servo valve 50 is incorporated in each suspension unit 10. Pressurized oil is supplied to the servo valve from a pump 52 via pressurizing lines 56 and 58, as schematically shown in FIG. The fluid discharged from the servo valve 50 is sent to a sump by a line 62. As shown schematically, the pump 52 pumps oil through an oil cooler 69 via lines 66,68.

When the spool of the valve 50 moves downward, the pressurized oil is supplied from the pressurizing line 56 to the annular chamber 70 in the nector block 30 through the flow passage 59, and the upper end of the outer piston rod 24 is further extended. Is supplied via a radial channel 72 in the section. When the pressurized oil fills the space between the inner and outer piston rods 22 and 24 as described above, the space between the outer piston rod 24 and the cylinder tube 12 is filled with the compressed oil through the openings 74 and 76. Thus, when the upper chamber 44 is filled with the pressurized oil, a downward force is applied to the piston 26. When a sufficient amount of force is applied by this pressure, the upper chamber 44 expands and the actuator unit contracts. In the state shown in FIG. 1, the upper chamber 44 is expanded to the maximum and the actuator unit is contracted.

The servo valve 50 not only supplies the pressurized oil to the upper chamber 44, but also moves upward to supply the pressurized oil to the inner chamber 80 formed between the inner cylinder tube 14 and the inner piston rod 22. You can also As in the upper chamber 44, the pressurized oil is directed by the servo valve 50 via line 73 to the opening 74 in the connector block 30.
The shape is an annular chamber. Pressurized oil is supplied to the inner chamber 80 via a radial passage 78 in the neck of the outer piston rod. When the pressure in the inner chamber 80 exceeds a predetermined pressure, the pressure in the inner chamber 80 acts on the chamber wall and the end of the inner cylinder tube 14, and the inner chamber expands to a predetermined length.

FIG. 2 shows a state where the inner chamber 80 is maximally expanded. However, due to the balance of forces in the expansion chamber and the contraction chamber, various states can be obtained between the states shown in FIGS. 1 and 2. It is possible to realize the state of.

An elongated rod 81 is secured to the top of outer piston rod 24, mounted within inner piston rod 22, and
A coil spring 85 extends into the interior of the coil 82 which is held in place. A load sensor is attached to the upper end of each piston rod assembly and is connected to the circuit 86. The rod 81 and the coil 82 cooperate to form a linear variable differential transformer 83, which provides the excursion signal, which is transmitted by the circuit 86 to the computer 84. . The computer 84 continues to receive signals indicating, for example, vehicle load, vehicle speed, bank angle, road curvature, lateral acceleration, and road undulations while the vehicle is in operation. These signals are processed by a computer, and the computer sends a control signal to the servo valve 50. Servo valve 50
Is operated by the torque motor 90. Computer 84
Is transmitted to the torque motor 90 via the circuits 92, 94, 96 and 98 to operate each actuator. Based on the input signal 86 coming into the computer, the torque motor adjusts the servo valve, which in turn adjusts the double-acting actuator, tilting the vehicle when turning and making adjustments under a wide range of driving conditions, to stabilize. Attenuation that allows the vehicle to turn while the vehicle is traveling straight ahead or is stationary is obtained by limiting the servo valve by adjusting the spool. This is possible with different control algorithms in different sensors and controllers, but any other control mode that is theoretically possible. With this device, it is possible to integrate the control of the front-rear and left-right inclination, the control of the damping and the spring rate.

In the preferred embodiment of the hydraulic actuator of the present invention described above, screwed to the base cap 16, or
An air suspension is provided as well, utilizing an outer support tube 100 that is otherwise secured. The outer support tube 100 extends upward from the base cap 16 and has a terminal end serving as a connecting portion 102 to the rod guide 28, and the connecting portion is bent inward to be air-sealed. The support tube 100 is spaced apart from the outer cylinder tube 12, and a cylindrical cavity 104 is formed between the outer tube and the support tube 100, and the cylindrical cavity is provided at the lower end of the cylinder tube 14. The lower chamber 46 is connected by a radial flow path 106. Compressed air for suspension is supplied by the controller 108 through line 110 to the cylindrical cavity 104 and the lower chamber 46. The compressed air acts within the lower chamber 46 to provide air suspension force to the suspension unit.
This trapped air amount is different from the oil amount, and the amount is such that an air spring is generated by the sliding piston, and the size of the air spring is It is sized to provide nearly proper loading and spring constant.

This air spring eliminates the need to support the static load of the vehicle on the hydraulic portion of the device, thus significantly reducing power consumption. In addition, it is not necessary to provide a coil spring around the actuator or other suspension device to support the static load, and furthermore, when the hydraulic mechanism is damaged and becomes inoperable, it goes into a streak mode. Without this, low speed operation becomes possible.

In the embodiment of the hydraulic expansion / contraction actuator described above, the high-pressure actuator for positioning the vehicle body according to the traveling device and the road surface of the vehicle is formed.
When the chamber 44 is pressurized, the unit contracts, while the chamber
When 80 is pressurized, the unit expands. This allows the four corners of the vehicle to be adjusted in height as needed, and the interlocking cylinder tube structure provides concentric and separate hydraulic chambers to improve the overall length of the unit. Has been shortened.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a preferred embodiment of the hydraulic actuator of the present invention, showing its contracted state, and FIG. 2 is the same as FIG. 1, showing the preferred embodiment of the hydraulic actuator of the present invention. FIG. 3 is a longitudinal sectional view of the embodiment, showing its extended state, and FIG. 3 is a partial diagrammatic view of a control mechanism for a suspension mechanism incorporating the hydraulic actuator of the present invention. 10 …… Hydraulic expansion / contraction actuator 12 …… Inner cylinder tube 14 …… Outer cylinder tube 22, 24 …… Piston rod means 26 …… Piston, 27 …… Hydraulic flow path 28 …… Piston rod guide, 34 …… Support structure 40 ... annular inner seal, 42 ... annular outer seal 44 ... first volume variable chamber, 50 ... control means 80 ... second volume variable chamber

Claims (3)

[Claims] 1. A piston rod means is connected to a reciprocating piston, extends from the connecting portion through a rod guide, and is connected to a vehicle support structure. Wheel assembly and vehicle support structure provided with control means for supplying one or the other of the variable volume chambers to expand the respective chambers and thereby extend or retract the piston rod means, respectively. In a hydraulic telescopic actuator for an active suspension system, the concentric inner and outer cylinder tubes (14, 12) form a nested cylinder tube assembly and define a cylindrical cavity between both cylinders. , A piston (26) is mounted so as to reciprocate in the cylindrical cavity, and A guide (28) is fixed to the upper end of the outer cylinder tube (12), and the piston has an annular inner seal (40) for sealingly contacting the contact portion with the inner cylinder tube and the outer cylinder tube. Annular outer seal for sealing contact with the contact part
By providing (42), the first variable volume chamber (44) is formed above the piston, and the piston rod means is
It comprises a hydraulic flow path (27) communicating with the first variable volume chamber, the control means (50) supplies pressurized hydraulic fluid to the first chamber to expand the first chamber, The actuator is adapted to contract, the piston rod means is mounted for telescopic movement with respect to the inner cylinder tube, and a second seal is provided between the piston and the inner cylinder tube. The variable volume chamber (80) is defined, and the control means supplies pressurized fluid to the second chamber to expand the second chamber, and thus expands the actuator. Hydraulic telescopic actuator. 2. An outer support tube (100) extends around the outer cylinder tube (12) and seals the cylinder tube to form an air chamber (104) therebetween to support the weight of the vehicle. Therefore, means for supplying compressed air to the air chamber at a predetermined air pressure is provided for this purpose, and means for changing the air pressure for causing the actuator to act as a variable suspension spring device is provided. The hydraulic expansion / contraction actuator according to claim 1. 3. The piston rod means are radially spaced and both are pistons (26).
Inner and outer piston rods (22,
24), wherein the hydraulic flow path (27) is defined between the inner and outer piston rods, and the inner and outer piston rods include the inner cylinder tube (14).
The hydraulic expansion / contraction actuator according to claim 1 or 2, characterized in that the hydraulic expansion actuator is mounted so as to perform a nested movement.