JPH05503903A - digital suspension system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] name of invention digital suspension system Koura I and Ichino The present invention is a hydraulic suspension system. em) and a digital actuator suitable for the suspension system. The present invention Specifically, the hydraulic suspension system and the suspension system are equipped with a digital computer force-regulated hydraulic suspension system. related to actuators used in

Mitsubishi Tachimei The use of computers for hydraulic control of automobile suspension systems is already known. Regarding the structure of the device and hydraulic actuator for controlling the suspension system Various methods have been proposed so far.

No. 4,333.668 (198 (Published June 8, 2013) with a damping orifice controlled by a solenoid. A shock absorber is disclosed. The solenoid is the extension of the absorber. tion) and operates under computer control.

The car's pitch and roll are also computer-controlled, with solenoid activation. The magnets open and close the valves, keeping the car in a nearly stable state.

U.S. Patent No. 4.639.013 (1987) to Williams et al. (published January 27) discloses an active vehicle suspension system, which uses gas springs (gas springs). A double-acting hydraulic actuator is placed in parallel with the It is set up.

By sensing the actual load change and adjusting the actuator appropriately, The known changes in load are corrected.

Canadian Patent No. 1,230,657 (1987) to Williams et al. (published on February 22nd) is an active suspension system that uses hydraulic actuators for each wheel. The position is disclosed, and a signal is generated according to the amount of displacement and the magnitude of the applied force, By controlling the displacement of the hydraulic actuator based on these signals, vehicle safety is achieved. Stay qualitative.

U.S. Patent No. 4,753,328 (1988) to Williams et al. (Published June 28) is based on earlier US patents and Canadian patents granted to Williams et al. This is a further improvement on the device described in the patent, which controls the piston movement of the actuator. A damping system that can selectively perform active or passive damping tem) is disclosed.

Digital hydraulic actuators are known. Amélie Granted to Robinson No. 4,602,481 (issued July 29, 1986) provides a pre-selected Digital actuator with different piston area to selectively apply force of magnitude Discloses specific examples of data. The applied force is the same as when the piston receives return pressure. Adjust the ratio of the piston area when receiving pressure from the pressure source to the ton area controlled by By selectively applying pressure, the actuator It is also possible to apply a force in the opposite direction. Pressure that drives the actuator in one direction The area of the piston when receiving pressure from the force source (high pressure) is calculated by moving the actuator in the opposite direction. To change the area of the piston when it receives the same pressure as when it is driven. Adjust the force so that it is positive in one direction. The combination of areas when subjected to pressure source pressure or return pressure can have a corresponding selection value.

Typically, digital hydraulic actuators are used when a double-acting mechanism is required. limited. This requires applying force so that it can be moved in two directions. This is because the total area or range of pressure that can be applied is limited. be. For this reason, it is necessary to suppress fluctuations in the pressure applied in any one direction. The size of the actuator increases significantly. America Granted to Robinson Patent No. 4,602,481 (issued July 29, 1986) describes this type of linear complex. A dynamic digital device is disclosed.

U.S. Patent No. 3,068,841 (December 1962) to Robbins et al. (Published on March 18th), the ram can be used as a workpiece even if the power and pump capacity are small. Discloses a device that can be rapidly moved toward a target location. This device is a piston After changing the size of the cylinder and positioning the ram, apply all the force to the workpiece. The desired result can be obtained by applying the

Generally, digital actuators have separate components, and the actuator It is connected to all individual valves, storage devices, etc. located remotely from the main body.

A simple escape from the original A The purpose of the invention is to reduce the force between the vehicle body and each wheel independently of the displacement of the actuator. Provides a vehicle suspension system that can be adjusted to maintain vehicle stability. It's about doing.

In a broader sense, the present invention relates to a suspension system for a vehicle body, the invention being concerned with a suspension system for a vehicle body. senses the lateral acceleration and longitudinal acceleration of the vehicle body and uses digital hydraulic actuators. The actuators support the vehicle body from each wheel, and each actuator has a different effective area. a plurality of actuator sections and a first source of hydraulic fluid at a first pressure; a second fluid source in which the hydraulic fluid is at a second pressure different than the first pressure; valve means for selectively connecting the first or second liquid source to the tuator section; and each actuator is connected to the first pressure or the second pressure by the valve means. for each actuator independently of the actuator extension. The applied force can be selectively varied, and the computer The control means controls the valve based on the condition sensed by the sensing means. Based on the predicted pressure at each actuator determined by computer means, the Actuator section of a digital hydraulic actuator connected to the first or second pressure The number of sections is adjusted to maintain the vehicle body in a nearly stable state.

Preferably, means are provided for measuring the displacement of each actuator; a signal representative of the displacement of the eta to computer means; , controlling the valve to maintain the actuator means in a preselected extended position. Let's do it.

Preferably, the hydraulic actuator has a rotor extending through the housing and a rotor extending through the housing. The protrusion that extends in the axial direction on the housing and protrudes in the radial direction is The projecting portions are provided at intervals in the circumferential direction to form multiple spaces in the circumferential direction, and the circumferential A pair of surfaces facing each other constitute opposite ends of each space in the circumferential direction, and the adjacent surfaces Each opposing surface of the protrusion has a different area, extends axially over the rotor, and Bosses protruding in the radial direction are formed at intervals in the circumferential direction of the Each space is divided on both sides of the boss to create a pair of actuators. The circumferentially spaced radial sides of each boss forming the evaporator section are , has approximately the same area as the opposing surfaces of the protrusions facing each other in the space, and has an edge in the circumferential direction of the space. The protrusion of the housing has an end surface that cooperates with the rotor, and the protrusion of the housing has an end surface that cooperates with the rotor. The surface of the space cooperates with the surface extending in the circumferential direction of the space to connect a pair of actuators in the space. One of the actuator sections is sealed and the boss is sealed in the other. was received from the actuator section of the rotor. Rotatably arranged within the housing, each boss moves a preset rotation within its respective space. The actuator can be rotated by the rotation angle, and a preselected pressure fluid is applied to each actuator. It is equipped with a means for feeding it into the data section.

It is a further object of the invention to arrange the various elements in a single unit. with a hydraulic output that can be connected to a suitable hydraulic actuator. Easy-to-install digital hydraulic actuator unit (assembly) Our goal is to provide the following.

In a broader sense, the invention further relates to a digital hydraulic actuator unit. The actuator unit includes a cylinder, a first element and a first element. body with a chamber connected to the body, forming a piston within the cylinder a second element, the first element and the second element forming a piston-cavity cooperative action; The unit further divides the chamber into a high pressure chamber and a low pressure chamber. The piston makes the low pressure chamber larger and the high pressure chamber smaller, filling the high pressure chamber and the low pressure chamber. means for moving the piston toward the high pressure chamber to create a pressure difference in the hydraulic fluid; A plurality of valves are provided in the main body, one for each pair of piston and cavity to act on. , first passage means passing through the main body and connecting the multi-valve to the high-pressure chamber; and connecting the low-pressure chamber to the multi-valve. a second passage means for each cavity of the cooperating piston and cavity pair; It has individual passageways leading to each valve.

The cylinder is connected to the cylinder by a fluid connection to one side of the hydraulic actuator. It is desirable to drive the actuator based on the pressure within the cylinder.

The chamber and cylinder are placed at both axial ends of the actuator unit. This is desirable.

Preferably, the main body further includes a valve means, and the first passage means connects the valve means to the high pressure chamber. the valve means is in communication with the low pressure chamber by the second passage means, and the hydraulic fluid connector is in communication with the low pressure chamber. is connected from the hydraulic actuator to the valve means, and the valve means is connected to the hydraulic actuator. is selectively connected to either the high-pressure chamber or the low-pressure chamber, and is supplied from the cylinder. The actuator can be driven in the opposite direction to the pressure applied.

In a broader sense, the invention further relates to a digital hydraulic actuator. The actuator includes a fixing element and a first member formed by the fixing element. a driven piston cooperating with the cylinder; The pressure acting between the fixed element and the wave piston in order to displace the wave piston means for digitally varying the force; and a second cylinder having a different cross-sectional area than the first cylinder. a cylinder and a coupling fluidly connecting the first cylinder to the second cylinder; Inside the second cylinder, the ratio of the cross-sectional area of the first cylinder and the second cylinder Equipped with an operating piston that is capable of imparting a force exerted by There is.

Preferably, the pressure acting between the fixed element and the driven piston is varied digitally. The means for causing the first set of piston cavities of different cross-sectional areas and the cross-section of the fixing element to a first set of pistons with different areas, and a second set of pistons with different cross-sectional areas; a second set of piston cavities having different cross-sectional areas; Each piston of the second set of pistons is housed in a respective piston cavity of the first set; Each cavity of the two sets of piston cavities can accommodate each piston of the first set. The selected pressure fluid is supplied to each cavity of the first and second set of cavities. means for selectively supplying the

Preferably, the means for selectively applying a pressure is a first pressure or a pressure different from the first pressure. supplying fluid at a second pressure to each cavity of the first and second sets of cavities; I try to do that.

Preferably, the working piston is a double-acting piston, and the working piston's fluid coupling is preferably a double-acting piston. Pressurized fluid is supplied with the side facing away from the ring facing down.

Preferably, a fluid coupling connects the first cylinder and the second cylinder. It has a straight cylindrical passage, and the cross-sectional area of the passage is equal to that of the first cylinder. It has a section that changes from a small cross-sectional area to a cross-sectional area equal to that of the second cylinder.

Preferably, the first set of cylinders and the first set of pistons have a common axis, The first set of pistons is separated to form a wall of each cavity of the first set of cavities. ing.

Preferably, the second set of cylinders and the second set of pistons have a common axis, The second set of pistons is separated to form a wall of each cavity of the second set of cavities. ing.

Preferably, the distance between the wave piston and the working piston is maintained within a preselected range. In order to do this, means are provided for adjusting the amount of liquid in the fluid coupling.

■Plate two! Rin left 13 Other features, objects and advantages of the invention will be apparent from the description of the accompanying drawings. It will become clear from the following detailed description of the preferred embodiments.

FIG. 1 is a schematic diagram of a vehicle illustrating a suspension system according to the present invention.

Figure 2 shows the digital hydraulic pressure when one of the wheels is in a position to support it against the wheel. 2 is a schematic diagram of an actuator.

Figure 3 is a diagram similar to Figure 2, but showing the preferred form of the hydraulic actuator. It is a diagram.

FIG. 4 is a schematic diagram of one form of hydraulic actuator used in the present invention.

Figure 5 shows how to control the pressure applied to the actuator section. FIG. 3 is a schematic diagram of the control valve used.

FIG. 6 is a schematic radial cross-sectional view of a preferred embodiment of a hydraulic actuator.

FIG. 7 is a sectional view of a preferred form of the digital actuator according to the present invention. .

FIG. 8 is a cross-sectional view of a preferred form of an actuator made according to the present invention. Ru.

FIG. 9 is a sectional view taken along line 9--9 in FIG. 8.

FIG. 1O is a sectional view taken along line 10-40 in FIG. 8.

FIG. 11 is a sectional view taken along the line 11-11 in FIG. 8.

FIG. 12 shows a device made according to the present invention, in which an actuator throttle 1 is a schematic diagram of an apparatus further comprising: FIG.

Desirable 2B The apparatus of the preferred embodiment of the present invention shown in FIG. 4) Can be applied to four-wheeled vehicles having (16). In addition, each wheel is a chassis (not shown in FIG. 1). The device is used for pitch and roll as well as vehicle Multiple accelerometers (accelerometers) measure vertical, lateral, and longitudinal acceleration of erometers). In the illustrated device, symbols (18) and (20) Five accelerometers shown in (22), (24), and (26) are designed. Accelerometer (I8) measures the acceleration of Fugo, and the accelerometer (20) is located vertically at one end of the car. The accelerometers (22) and (26) measure the vertical acceleration on both sides of the car. The accelerometer (24) measures the horizontal lateral acceleration. The acceleration mentioned above The meters (I8) to (26) each send a signal representing the acceleration measurement to the control computer. The data is transmitted to the controller (28). The control section (28) includes a control valve device (30) ( 32) (34) (Each control valve device is composed of multiple valves, and regarding this will be explained later), and sends a signal to each of the wheels (10), (12), (14) (1 6) respectively control the hydraulic actuators (42) ((57) and (200)). do.

In the device shown, the hydraulic circuit of the actuator (42) is connected to the high pressure tank (38) and the low pressure tank (38). It contains pressure tanks (40), which are connected to valve devices (30), (32), and (3). 4) (36), and each position of the wheels (10), (12), (14), and (16). A digital hydraulic actuator (42) controls the force generated. Actue Regarding the actuator (42), the actuator (57) (2) shown in FIG. 4 and FIG. 00) will be described in more detail below.

In the illustrated embodiment, the hydraulic pump (44) pumps fluid at high pressure (P, l) into a high pressure system. Supplies the cylinder (38) and maintains the low pressure cylinder (40) at low pressure (PL) do. Note that there is a significant difference in the pressure difference between the high pressures P and l and the low pressure PL.

Hydraulic actuators can adjust the applied force independently of the telescoping motion. Any suitable material can be used as long as it is possible. computer control section (28) is the actuator according to the model of the digital hydraulic actuator used. Activate the valve of the motor (12). Specifically, double-acting actuators (the force is generated by two single-acting actuators (force is applied in one direction only) and single-acting actuators (force is applied in only one direction). The control is different when using (added). 2 types shown in Figure 4 and Figure 6 An example of this is shown.

An example of mounting a hydraulic actuator acting in the axial direction is shown in FIG. In Figure 2 , the piston-cylinder type actuator (42) (see Fig. 4) is connected to the vehicle body ( 46) and the suspension device (48) in the axial or longitudinal direction.

In addition, in the drawing, wheels (10), (12), (14), and (16) are attached to the suspension system. It is attached. In Fig. 3, a torque type digital actuator (42A) ( In Fig. 6, the double-acting torque type actuator (200)) is connected to the vehicle body (46) and each Between the suspension device (48) for the wheels (10) (12) (14) (16) It is being deployed. The actuator (42) (or (42A)) is a single-acting actuator. Either an actuator or a double-acting actuator may be used. In Figure 4, it expands and contracts in the axial direction. The single-acting actuator (57) shown in FIG. No. 2,481 shows a double-acting actuator that extends and retracts in the axial direction.

Generally, when using a double-acting actuator, each wheel (10) (12) (1 4) In order to support the vehicle body part (46) at the position (16), use a suitable suspension spring (43). It is desirable to use it simultaneously with a digital hydraulic actuator.

A single acting piston-cylinder type actuator (57) is shown in FIG. this The device shows two high pressure sources (38), one actuator (57). ) for the upper section (59) of the actuator and the other one for the lower section (59) of the actuator. This is for version (76). In the following description, only reference will be made to the high pressure source (38). . Note that it is not necessary to provide a separate low pressure source (38) for each section. do not have. The pressure of the high pressure source is P, while the pressure of the low pressure source (40) is lower than this. Low pressure is 9.

A high pressure source (38) is connected to valves (52) (54) (56) via a manifold (50). connected to and forming part of each valve device (30), (32), (34), and (36). Ru. These valves are connected to a low pressure source (40) via a low pressure manifold (58). Ru. Answers (52), (54), and (56) are the upper part (59) of the actuator (57). an annular chamber with a common axis; - (60), (62), and (64), respectively. chamber or section ( 60), (62), and (64) are centered around the common axis (66) of these chambers. The effective cross-sectional areas are different when measured in the radial direction.

In the same way, separate the chambers or sections (60), (62), and (64). An annular ring divider is connected to the second or bottom section of the actuator (57). a second set of annular chambers formed with a common axis (66) in the section (76); - (68) (70) (72) (74).

Section (60) (62) (64) (68) (70) (72) (7 For example, the effective cross-sectional area of the chamber (60) is Preferably, the chamber (62) is twice the size of the chamber (64). It is desirable to double the amount. However, what is important is that the effective cross-sectional area of these chambers The purpose is not to make them stepwise like this, but to make them different in area.

A chamber (60) formed in the upper part (59) of the actuator (57) ( 62) (64) are connected to the valves (50) (52) (56), respectively, and the lower part ( The chambers (68), (70), (72), and (74) formed in 76) are respectively , connected to valves (78) (80) (82) (valve device (30) (32) There are valves (78), (80), and (82) in each of (34) and (36). these The valve is connected to a high pressure source (38) through a high pressure manifold (86) and (88) to a low pressure source (40).

The control unit (28) includes valves (52) (54) (56) (78) (80) (8 2) Activate each of (84) to activate each of the various sections (60), (62), and (6). 4) (68) (72) (74) from either the high pressure source (38) or the low pressure source (40) Connect to one side. Therefore, let's separate the two units (59) and (76). The total force is cylinder (60) (62) (64) (6g) (70) (7 2) Depends on the sum of the forces in (74). The sum of these forces is It is obtained as the area of the bar multiplied by the pressure in each chamber, and the pressure is Depending on the fluid source used, either P or PL is selected.

Valves (52) (54) (56) (78) (80) (82) (84) are activated. Any suitable device that allows the evaporator section to be connected to either pressure source can be used. However, the operation of the device is limited by referring to the valve shown in Figure 5. I will refer to and explain.

In this device, the valve has a control solenoid designated (90). This control The solenoid (90) may be any suitable material that can move the body of the valve. Solenoids can be used. The solenoid (90) has two cylinders (92) is connected to (94), and the cylinder is moved back and forth to create a high pressure inlet. The port (96) and low pressure inlet boat (98) are opened and closed. Intermediate boat (10 0) separate the valves into their respective sections or chambers (60) (62) (64) ( Connect to 68) (70) (72) (74). If the valve moves, e.g. The port (96) is closed and the port (911) is open, but the port is closed as shown by dimension X in the figure. Port (98) opens before port (96) is fully closed. the valve moves in the opposite direction A similar phenomenon occurs when port (98) is closed and port (96) is opened. Jiru. Cylinder (92) (94) for opening and closing ports (96) (98) ) is moving at a fairly high speed, so the time that both boats are open at the same time is very short. Ru. Therefore, the pressure will not increase significantly while switching between high pressure source and low pressure source. do not have.

Each cylinder (60) (62) (64) (68) (70) (72) (74) may be connected to either the low pressure source (40) or the high pressure source (38). seed The ratio of effective area within each section or chamber, e.g. When the effective cross-sectional area of separating the two sections (59) and (76) by connecting them to It is possible to apply additional pressure.

The high pressure source PH and the low pressure source P are substantially constant pressure sources, and for example, there is an air at the top of the fluid. Pressure is applied to maintain a substantially constant pressure. Therefore, flow has a substantial negative effect on pressure. It will not affect you. Simply put, the low pressure PL may be atmospheric pressure.

The pressure sources (38) (40) are used to control the flow of hydraulic fluid to the actuator or the extended state of the actuator, i.e. the upper (59) and lower (76) of the actuator (57). Essentially the same pressure can be maintained on the valve regardless of the state of separation It is of the model type. For example, the relative rotation of the rotor and housing in FIG. (38) This can be done by maintaining the air pressure in (40) approximately constant. Ru.

Various chambers (60) (62) (64) (68) (70) (72) ( Valve (52) (54) (56) (78) for sending appropriate pressure into 74) (80), (72), and (84) are controlled by the computer control section (28). can be done. This is done based on the expected amount of chassis movement. Then, the signals from the accelerometers (18) (20) (22) (24) (26) are based calculations to determine the expected travel of the chassis with respect to the wheels. . Calculations are performed using the weight and center of gravity (hypothesized or determined), and the vehicle body (46 ) is determined by the force required to prevent it from moving at each wheel position.

In order to calculate the force that can be applied to the actuator, it is necessary to know the acceleration. In addition, the weight and center of gravity of the vehicle must be assumed or determined. child Therefore, suitable means may be provided on each suspension system to take up the weight of the vehicle. . The weight of a car can be easily determined by measuring the amount of movement of the suspension system and using that measurement. You can simply wear it. That is, each wheel (10), (12), (14), (16) The actuator (42) (42A) in the position is indicated by the reference numeral (104) in FIG. Measure the angular position of the wheel with a suitable measuring device such as The measurement can be carried out using a measuring device as shown.

Signals from accelerometer (1g) (20) (22) (24) (26), each wheel (104) Signals from the actuator extension measurement device above and other measurement devices signals from the control unit or control computer ( 28).

The control computer (28) determines the force to be applied by each actuator; Valves (52) (54) (56) (78) (80) of each valve block (34) Calculate the positions of (82) and (84).

In a preferred embodiment of the invention, the force to be applied by each actuator is the latest value, preferably the accelerometer and extension signal (extension si gnals) is calculated as a weighted sum of several previous values for each. weight person The numbers relate to known modern linear control theory, preferably optical linear quadratic equation control theory. It is calculated using the Ritsukachi equation and vehicle parameter information. define the car Parameters include mass, mass moment of inertia, and dimensions, which are The program can be installed on the computer when it is installed.

In a preferred embodiment, the vehicle parameters include an accelerometer and a stretch signal and an actuator. It is determined from the power of the evaluator.

To calculate the parameters, an appropriate calculation procedure is used, for example, using the maximum likelihood statistical method. can be made. In this case, the control computer calculates the force of the actuator. In addition, calculations are periodically performed to determine the car parameters and the weights described above are The calculation coefficient is calculated and corrected according to the difference in vehicle load conditions. Normally, the actuator The eta force calculation is repeated at least every 0.1 seconds. On the other hand, Wei Ting Calculate the calibration factor at least every 10 seconds, preferably at shorter intervals. Now.

Calculating the force of the actuator every 0.1 seconds will result in changes in direction, acceleration, and braking of the car. It is also able to respond quickly enough to changes in the road surface conditions the car is driving on. .

The most important function of the suspension system is to respond to changes in the road surface. ) can be made virtually unrelated to the road surface. However, the wheels (nominal position) (generally about the wheel storage compartment) (center), the suspension will reach its suspension limit and the The impact is transmitted to the vehicle body (46). To avoid this, suspend the vehicle in its normal position ( The suspension system moves the vehicle body part (46) sufficiently to keep the wheels relative to the body part. I have to let it happen. With rigid suspension, the wheels are held in their normal position. but , there is an inconvenience that the unevenness of the road is transmitted to the vehicle body (46). In this case, the wheels can move freely with respect to the car body (46), so the car body part is not affected by the road surface. However, if the suspension limit of the suspension system is exceeded, the shock There is an inconvenience that this is transmitted to the vehicle body. The computer control controls the selected suspension system. To reveal the type, the active suspension system must be controlled. which one In this case, as with conventional suspension systems, the impact exceeds the suspension limit and is transmitted to the vehicle body (46). We must react in a way that prevents this from happening.

In a preferred embodiment of the invention, the hydraulic actuator is shown in FIGS. , using a torsional actuator as shown at (200). ing. The torsional actuator includes a rotor (204) within a housing (202). or has been deployed. The rotor (204) has a shaft (208) extending in the axial direction. It is fixed to the suspension arm (48) of the wheel. Therefore, the attachment to the vehicle body (46) is The angular position of arm (48) positions rotor (204) relative to housing (202). It is adjusted by rotating.

The torsional actuator (200) shown in FIG. 6 is an axial actuator (57). and similar parts to those in the embodiments of FIGS. 4 and 6. They are given the same quotation marks. The torsion actuator (200) expands in the circumferential direction. Multiple spaces (208) (210) (212) (214) are formed. . A space (20g) is formed between the protrusions (216) and (218), and a space (210g) is formed between the protrusions (216) and (218). ) is formed between the protrusions (218) and (220), and the space (212) is formed between the protrusions (220). 0) (222). Furthermore, the space (214) is connected to the protrusion (222) and the rod. between the surfaces (224) formed on the data (204).

The rotor (204) has bosses (242) (244) (246) spaced apart in the circumferential direction. will be deployed. These bosses are located around the space (208) (210) (212). The length in the direction is short and is accommodated in each space, and each of these spaces is connected to an actuator set. (208A) (208B), (210A) (210B), and (21 2A) (212B).

In the structure shown, ports (228) (230) are connected to protrusions (218) (216). sections (208A) (208B) adjacent to the valves (80 ) (56). Similarly, section (210B) (210A ) are located adjacent to the protrusions (218) (220) and the ports (232) (23 4) and are connected to valves (54) and (82), respectively. Section (212 B) (212A) is a port located adjacent to the protrusion (220) (222) (236) and (238), and are connected to valves (52) and (84), respectively.

Section (214) connects to valve (78) via port (240) be done.

The bosses (242), (244), and (246) are surrounded by spaces (20g) and (21g), respectively. 0) Wiping relationship with the surroundings of (212) Sections (208A), (208B), (21OA) and (21OA), respectively. 0B), and (212A) and (212B). Similarly, The origin (216) (218) (220) (222) is the circumference of the rotor (204). It is in a sealed relationship with the enclosure, and sections (208A) (208B), (210A) ( 210B) and (212A) (212B) (214) are further sealed. do.

The area of the surface (224) of the space (214) is substantially the same as the area of the opposing surface of the protrusion (222). It is clear that they are equivalent. Multiple actuators with different effective cross-sectional areas in the radial direction ducer sections are circumferentially spaced around the rotor.

The radial area of a matched pair of adjacent faces is specified relative to the radial area of another matched pair. By combining the cross-sectional area when subjected to different pressures, the (201!A) (208B) (210A) (210B> (212A ) (212B), respectively, to valves (80) (56) (82) (54) (84) (5 2) By selectively connecting to the high pressure source P□ or the low pressure source P via (78) to create the desired force.

The torsion actuator (200) is a double acting actuator, as shown in FIG. The suspension device (48) can be moved clockwise or counterclockwise under the control of the computer (28). Pressure is applied to rotate the suspension system in either direction, and the suspension system is 6) can be maintained in the desired position. Single acting actuator is available for each car. Change the magnitude of the force applied between the wheels and the vehicle body (46), but without changing the direction. , can only be operated to maintain the suspension in its normal position.

The digital hydraulic actuator (310) shown in FIG. a plurality of annular piston cavities (314); )(316)(318)(320) form a first set of piston cavities; These are annular pistons (322) (324) ( 326) (328).

The wave piston, or second element (33G), comprises a plurality of pistons forming a second set of pistons. annular pistons (332) (334) (336) and a second spaced apart piston (332) (334) (336) sets of annular piston cavities (338) (340) (342) (344) is formed. The second set of pistons (332) (334) (336) is Housed in the first set of piston cavities (314) (316) (31g) The first set of pistons (322), (324), (326) (32g) are Second set of piston cavities (33g) (340) (342) (34 4). Each cavity (314) (316) (318) (334 ) (340) (342) (344) are lines (346) (348) (35 2) Through the (354), (356) and (35g), the valves (360) ( 366) (3H) (370) (372). These answers are It is essentially the same and is also essentially the same as the valve illustrated in FIG. answer from the first position connecting each cylinder to the high pressure tank (37 6) (High pressure line (374) leading from the above tank (38) (equivalent to (50) or (86)), or also the operation indicated by the symbol P, Low pressure line (37g) connected to dynamic fluid source (380) (tank (40) above) ) (the above-mentioned line (58) or (88)). child These valves (360) (362) (364) (366) (368) (37 0) (372> is connected to the control unit (382) by the line (384), Either high pressure or low pressure so that one pressure can be applied to each cavity and all the pressure that tries to separate the two elements (312) (330) can be varied.

various in the first and second set of cavities forming the actuator (310). By directly relating the cross-sectional area of the cavity, digital effects can be obtained and various keys can be created. selection by appropriately connecting the cavity to either a high pressure source or a low pressure source. It is desirable to increase the pressure in the process. That is, the cross-sectional area of each cavity is a direct ratio to the cross-sectional area of other cavities, ie, a multiple of 2.

The actuator (310) forms an annular body or first cylinder (386). It extends integrally to the element (312) in which the driven piston immediately The second element (330) cooperates with the hydraulic piston (330) and the cylinder ( 386). The axial length of the cylinder (386) is in the piston cavity, the first and second sets of pistons are in the most extended state. At any given time, the dimensions are sufficient to ensure movement of the piston (330). Siri guided by the cooperative action of a piston (330) in a small A piston element, e.g., extending between the wave piston (330) and the first element (312). This prevents the first and second sets of pistons from being damaged.

The cylinder (386) connects to the second piston via a hydraulic connection section (38g). a second cylinder (392) containing a working piston (390). It will be done. In the structure shown, this connecting means is preferably a straight tube, but if necessary, Alternatively, it can also be formed by bending it using a connector such as a hydraulic hose. illustrated In the structure, the cross-sectional area of the piston (390) is smaller than the cross-sectional area of the piston (330). The piston (330) is also extremely small through the fluid coupling (338). ) is applied to the piston (390) and the piston connected to the piston (390). This will correspond to the pressure applied to the ton rod (394). Piston (33 When the area ratio of 0) and (390) is 10:1, it is added to the piston (390) The force is 1710 times that of the piston (330) (total pressure is essentially the same). ). If piston (390) moves freely, piston (330) If the piston (390) moves by l/10, the piston (390) will move the entire length.

In this way, by changing the cross-sectional area of the pistons (330) and (390), the movement The amount of movement of the actuating piston (390) can be significantly increased.

Adapted to the difference in cross-sectional area between the first cylinder (386) and the second cylinder (392). In order to Gradually from the large area of the Linder (386) to the small area of the Cylinder (392) It is changing to

Coupling (3) is used to move element (330) in the direction of element (312). 8g) via the line (396). Connect to two position valves (398). The valve can be connected to a high pressure source. one On the other hand, between the element (312) and the element (330), a first and a second set of cavities are provided. A sufficient number of cavities in the cavity are connected to a low pressure source. Therefore, the piston ( 390) acts in the direction of the piston (330), and the piston (390) Forced to move upward in FIG. 7, the element (330), that is, the piston (330) 312).

As mentioned above, the valves (360) (362) (365) (366) (36 8) (370) (372) (398) were explained with reference to Figure 5 - pressure or other pressure source.

Hydraulic fluid connector (3811) allows fluid addition or addition via outlet (408). Apparatus can be provided for carrying out the removal. This device is a computer (8 2) and as shown by the arrows (412) (414), the sensor (4 According to the relative positions of the pistons (330) (390) measured in 00) (402) , fluid can be added or subtracted.

In the above explanation, only two types of hydraulic pressure are described, but three types can be applied using appropriate valves. Higher hydraulic pressures can be used. In this way, from among several different pressures, Any one pressure can be selected to act on the cavity.

FIG. 8 shows a preferred embodiment of the invention, including the valve, high pressure source, low pressure source and output. Arrangement a (450) is constructed by appropriately arranging and combining all the cylinders. .

In Figure 8, parts similar to those shown in Figure 7 have the same reference number. The text is appended to the end, and repeated explanations regarding the digital hydraulic device will be omitted ( However, compared to the structure shown in Figure 7, two elements (312A) and (330A) There is one less piston and cavity inside. That is, the piston (328) and the A corresponding cavity (344) is not provided in the structure of FIG. 8). to some valves Therefore, numbers different from those used in FIG. 7 are given.

A compact digital actuator device is shown in FIG. A cylinder part (452) constituting a pressure cylinder (386A) at one end of the direction This cylinder is the cylinder (386) shown in the embodiment of FIG. is essentially the same. The opposite axial end of the unit (45) has a chamber. A bar (454) is provided.

Between the cylinder (452) and the chamber (454) is a first element (312A). ) is provided with a main body (455) made from.

This acts in conjunction with the movable element (330A) (second element) or piston.

In addition, various disc-shaped elements (456) (458) (460) can be combined. A passageway is formed to accommodate the valve. This will be explained later .

The device (450) has various elements arranged approximately symmetrically around the long axis (462). ing.

The chamber (454) is indicated at (376A) by a piston (464). The chamber is divided into a high-pressure chamber P, and a low-pressure chamber P, designated by the symbol (380A). It will be done. The piston (464) is connected to the high pressure chamber by suitable means (466) such as a spring. (376A) and the high pressure chamber <376A) and the low pressure chamber - (380A). That is, the spring (466) is connected to the piston ( 464) reduces the size of the high pressure chamber (376) and lowers the Increase the size of the pressure chamber (380A) to create a gap between high pressure PH and low pressure PL. Maintain pressure differential.

In the structure shown, the disk (456) is provided with an axial protrusion (468). A passageway (470) extends through the protrusion. Piston (464) is axial The protrusion (468) in the direction is slid tightly.

Various valves (as mentioned above, (360) (362) (364) (366) etc.) in its entirety under the quotation mark (472) (all valves have the same quotation mark). These valves are elements (312A) (460) (458) ( 456) in the main body (455). Figures 9, 10 and As is clear from FIG. 11, around the axis (462) of the cavity (474) arranged symmetrically.

A first path communicating valve (472) with high pressure chamber (376A) is radially Route (476) (478) (480) (482) (484) (48 6) by a long passageway (470) communicating with the cavity (474) through be done.

Referring to FIG. 9, an additional cavity (474) is formed to further accommodate the valve. I am trying to make it possible to include it.

In this case, the valve is substantially the same as the valve (398) in the previous embodiment, with the first Pathway (490) connects hyperbaric chamber (376A) to valve (396). It is connected to a similar valve (472).

Each of the valves (472) has a separate path, i.e. an axially extending path (504) ( Route (492) connecting (506) (508) (510) (512) (514) ) (494) (496) (500) (502), element (312A ) (330A) is connected to each cavity of the digital actuator formed. (See Figure 11).

Referring again to FIG. 10, valve (396) is inserted into cavity (4) containing an equivalent valve. 74) is provided with a radial path (516) communicating with the axial path (518). I get kicked. The path (518) is connected to a fitting (520) for connecting to a hydraulic hose, etc. connected, which will be explained later.

The low pressure chamber (380A) has an axial path (522) (FIGS. 9 and 10). (see) to the circumferential groove (524) which communicates with the cavity (474). (See Figure 11).

To function properly, the piston (330A) must have free piston movement. A device is provided to restrict the movement of the piston (330A) from the element (312A). Do not let it come out or come into contact with one end of the cylinder (452). Ru.

This movement restriction device is formed by an annular groove (526) (see FIG. 8), The shaped groove includes an axial path (528), a radial projection (530), and a radial radius. Pass through the passage (582) and passage (470) to the high pressure chamber (376A) (Fig. and Figure 9).

The second annular groove (532) is axially spaced from the groove (526) in the cylindrical wall. is provided and connected to an axial path (534), which path is connected to a radial path (534). (536), the connecting path (524), and the axial path (522) to the low pressure chamber (3 80A) (see Figures 8, 9 and 10).

The piston (330A) has a circumferential groove (538) formed on its outer surface, that is, around the circumference. and is connected to the inside of the cylinder (386A) through an L-shaped path (540). .

The movement restriction device operates as follows. The piston (330A) is at the end of the cylinder If the groove ( 538) are aligned on the same line as the groove (526), so the inside of the cylinder (386A) is connected to the high pressure chamber (376A) through the path (528) and the piston (3 30A) is forced towards element (312A). On the other hand, the piston (330A) is too close to element (312A), the groove at (538) is identical to the groove at (532). The cylinder (386A) is located on the line (534) (536) (53 8) etc. and connects to the low pressure chamber (380A). Therefore, if the digital actuator When any of the pistons and cavities of the motor device are under high pressure, the piston ( 330A) is forced into the cylinder (386A) away from the fixed element (312A) Proceed to.

Assuming that the device of the invention is deployed in an active suspension system, each wheel can be mounted, e.g. For piston cylinder structures such as stone (390A) and cylinder (392A) would be supported by an actuator (399) formed thus, e.g. For example, the piston shaft designated by the symbol (394A) is connected to the wheel and the cylinder The main body of the driver (392A) is connected to the vehicle body. Regardless of the purpose, cylinder High pressure fluid from the cylinder (386A) is transferred to the double piston and cylinder (390A). ) (392 people) is connected through the line (388A) to one side of the cylinder. - The unit pressure in the piston (390A) is substantially equal to the unit pressure in the piston (386A). is supplied to.

Opposite ends of the piston (390A) and cylinder (392A) (392A) is a suitable coupling such as the hose coupling shown at (396A). It is connected to a connector (520) by a coupling. This is a valve (396 ), and the valve (396) is normally connected to the low pressure chamber. (380A). To drive the piston (390A) in the opposite direction. For this purpose, a valve corresponding to valve (396) is moved to direct high pressure fluid into the chamber described above. (392A).

Figure 12 is a diagrammatic representation somewhat similar to Figure 8, but here the point A pump (600) is further provided which pumps the high pressure line through a valve (602). Connected to line (374) (374A) and low pressure line (378) (378A) These pressure lines are connected to a high pressure source (376) (376A) and a low pressure source (376A). 80) Connected to (380A).

The apparatus shown in FIG. 12 further includes an actuator throttle (604). The purpose of this throttle is to prevent the working piston ( 390) (390A) (394) (394A).

The actuator throttle (604) includes a throttle valve (606), and throttles the pressure line from the cylinder (386) (386A) to the orifice (60 8), or this aperture office (608) in the position shown. ) so that it can be connected directly to the cylinder (386) (386A). I'm doing it. In the same way, the return line (396) (396A) connects the valve ( 606) directly to the low pressure chamber (380) (38OA). , the low pressure chamber (380) (3 80A).

Movement of valve (606) is caused by lines (396) (396A) and (388) (388 A) through valve control pressure lines (612) (614) connected to valve (606) This can be achieved by a pressure difference between the hydraulic pressures acting on both ends of the . Throttle (6 04) operates as follows.

When there is no load on the operating piston (390) (390A), there is no pressure on the operating piston. There is no difference. Therefore, a total pressure difference is applied to the throttle. throttle The velocity of the flow through the throttle orifice (608) and therefore the velocity of the piston is determined by 10) is a function of its size and the pressure difference thereon. In extreme cases the piston When there is no movement, there is no pressure difference on the throttle and the total pressure difference acts on the working piston. do. By providing the valve (606), the action on the throttle is reduced when the pressure is high. , always from the actuator (399) through the flow lines (388) (396). It is done. This throttle is effective in preventing cavitation.

To incorporate the device of the invention, four connections are required: cylinder (386A); (i.e. connection to line (388A)), connection to fixture (520), chamber Low pressure line to (3gOA) and high pressure line connection to chamber (376A) It is clear that a continuation is necessary.

Although the present invention has been described, a person skilled in the art would understand that the invention described in the claims Transformations can be made without departing from the spirit.

FIG. 5 FIG. 4 FIG. 6 FIG.9 FIG. 10 FIG. abstract A digital suspension system for vehicles, with a built-in digital hydraulic actuator in each wheel. and detects the lateral acceleration and longitudinal acceleration of the vehicle body, as well as the position of each wheel with respect to the vehicle body. This information is sent to a computer. computer The controller calculates the force required by each wheel and controls each wheel's digital hydraulic actuator. The amount of increase in force applied to each actuator between the wheel and the vehicle body. to maintain the vehicle in a nearly stable position. Hydraulic actuators used in suspension systems The eta is shaped by a device including a first element, a cylinder, a body and a chamber. It is desirable that the The first element includes several piston cavities of different sizes. A second element has a plurality of piston elements and a piston element. a cavity is provided, and the first element and the second element act cooperatively. . The second element forms the piston within the cylinder. On the main body side, preferably the axis It has multiple valves built in, with the axis of symmetry as the axis of symmetry. A valve consists of a cooperating piston and a cap. One for each combination of bits.

The piston divides the chamber into a high pressure chamber and a low pressure chamber, and the piston is biased toward the high pressure chamber. This creates a pressure difference between the high pressure chamber and the low pressure chamber. The passageway answers the high-pressure chamber and low-pressure The answer is to select each cavity as either a high-pressure chamber or a low-pressure chamber. It allows for selective connection.

international search report memlmSIApp-1-No　DI’ding/rm　01/n1in Uni International inspection report International investigation report

Claims (1)

[Scope of Claims] (1) A vehicle suspension system that senses the lateral acceleration and longitudinal acceleration of the vehicle body using a sensing means, and supports the vehicle body from each wheel using a digital hydraulic actuator, Each actuator includes a plurality of actuator sections having different effective areas, a first source of hydraulic fluid in which the hydraulic fluid is at a first pressure, and a second source in which the hydraulic fluid is at a second pressure different from the first pressure. a source of hydraulic fluid, and valve means for selectively connecting either the first or second source of hydraulic fluid to a selected actuator section, the valve means varying the number of actuator sections. , the first pressure or the second pressure By changing the effective area of each actuator connected to the force, the extension of the actuator is independent The force applied to each actuator can be selectively varied by vertically adjusting the valve, and the valve control is performed by computer means, and the sensing means senses the and adjusting the number of digital hydraulic actuators connected to the first or second pressure based on the predicted pressure of each actuator determined by computer means based on the conditions determined, thereby maintaining the vehicle body section in a substantially stable condition. A vehicle suspension system that makes this possible. (2) comprising means for measuring the displacement of each actuator and providing a signal representative of the displacement of each actuator to the computer means; 2. A suspension system according to claim 1, wherein the valve control is adapted to maintain the motor means in a preselected extended position. (3) The suspension system according to claim 2, wherein each actuator is a double-acting actuator. (4) The hydraulic actuator has a rotor that passes through the housing. A protrusion that extends in the axial direction on the housing and protrudes in the radial direction is spaced in the circumferential direction of the housing. Protruding and recessing at intervals forms multiple spaces in the circumferential direction, and the adjacent protrusions are opposed in the circumferential direction. A pair of opposing surfaces constitute circumferentially opposing ends of each space, and the opposing surfaces of adjacent protrusions have different areas, and form a boss that extends axially on the rotor and projects radially. are formed spaced apart circumferentially of the rotor, each boss being housed in a different space, each space being divided on either side of the boss to form a pair of actuator sections, and each boss having a radius of The sides of the direction are the pairs of protrusions that are opposite in the space. having approximately the same area as the facing surface and forming a circumferential edge of the space, the protrusion having an end surface that cooperates with the rotor, and the boss cooperating with a surface extending in the circumferential direction of the space, Sky sealing one actuator section of a pair of actuator sections within the space, the bosses being received from the other actuator section, the rotor being rotatably disposed within the housing, and each boss pre-sealing within the respective space. 2. The suspension device according to claim 1, wherein the suspension device is rotatable by a set rotation angle and includes means for feeding hydraulic fluid at a first pressure or hydraulic fluid at a second pressure to each actuator section. (5) The hydraulic actuator has a rotor that passes through the housing. A protrusion that extends in the axial direction on the housing and protrudes in the radial direction is spaced in the circumferential direction of the housing. Protrusions are provided at intervals to form multiple spaces in the circumferential direction, and adjacent protrusions are A pair of opposing surfaces constitute circumferentially opposing ends of each space, and the opposing surfaces of adjacent protrusions have different areas, and form a boss that extends axially on the rotor and projects radially. are formed spaced apart circumferentially of the rotor, each boss being housed in a different space, each space being divided on either side of the boss to form a pair of actuator sections, and each boss having a radius of The side of the direction is the pair of protrusions that are opposite in the space. having approximately the same area as the facing surface and forming a circumferential edge of the space, the protrusion having an end surface that cooperates with the rotor, and the boss cooperating with a surface extending in the circumferential direction of the space, Sky sealing one actuator section of a pair of actuator sections within the space, the bosses being received from the other actuator section, the rotor being rotatably disposed within the housing, and each boss pre-sealing within the respective space. 3. The suspension device according to claim 2, which is capable of rotating by a set rotation angle and includes means for feeding hydraulic fluid at a first pressure or hydraulic fluid at a second pressure to each actuator section. (6) The hydraulic actuator has a rotor that passes through the housing. The protrusions extend axially on the housing and protrude in the radial direction, and the protrusions protrude at intervals in the circumferential direction of the housing. A pair of surfaces forming a plurality of spaces in the direction and facing each other in the circumferential direction of adjacent protrusions. The surfaces constitute opposing ends in the circumferential direction of each space, and each opposing surface of the adjacent protrusion The surfaces have different areas, and bosses extending in the axial direction and projecting in the radial direction on the rotor are formed at intervals in the circumferential direction of the rotor, and each boss is housed in a different space, Divide each space on both sides of the boss to form a pair of actuator sections. The radial side surface of each boss is approximately the same surface as the opposing surface of the opposing protrusion in the space. and forming a circumferential edge of the space, the protrusion forming an edge cooperating with the rotor. The boss has a surface, and the boss cooperates with the surface extending in the circumferential direction of the space to connect a pair of axes in the space. One of the actuator sections is sealed in space, the boss is received from the other actuator section, and the rotor is in the housing. The bosses are arranged rotatably within the chamber, and each boss can rotate within its respective space by a preset rotation angle, and allows the hydraulic fluid at the first pressure or the hydraulic fluid at the second pressure to be delivered to each opening. 4. A suspension system according to claim 3, further comprising means for feeding into the actuator section. (7) The rotor passes through the housing and extends axially over the housing. The protrusions protruding in the radial direction are provided at intervals in the circumferential direction of the housing. A pair of circumferentially opposing surfaces of adjacent protrusions form each space. The opposing surfaces of adjacent protrusions have different areas, and the bosses extending axially on the rotor and protruding radially on the rotor are The bosses are formed at intervals in the circumferential direction of the cylinder, and each boss is accommodated in a different space. each space is divided on opposite sides of the boss to form a pair of actuator sections, the radial side surfaces of each boss having approximately the same area as the opposing surfaces of the protrusions facing each other in the space, and the radial side surfaces of each boss having substantially the same area as the opposing surfaces of the protrusions facing each other in the space; The protrusion has an end surface that cooperates with the rotor, and the boss cooperates with a circumferentially extending surface of the space to move the pair of actuators in the space. one of the actuator sections is sealed within the space, the bosses are received from the other actuator section, the rotor is rotatably disposed within the housing, and each boss moves within its respective space by a preset angle of rotation. A hydraulic actuator capable of rotation and having means for delivering a preselected pressure fluid to each actuator section. (8) a fixing element and a first cylinder formed by the fixing element cooperating with each other; A fixing element is used to displace the driven piston of the first cylinder and the driven piston of the first cylinder. means for digitally varying the pressure acting between the driven piston and the driven piston; a second cylinder having a different cross-sectional area from the first cylinder; a fluid coupling connected to the cylinder and a fluid coupling in the second cylinder connecting the first and second cylinders; (9) A digital hydraulic actuator comprising a working piston, making it possible to apply a force determined by the ratio of the cross-sectional areas of the cylinder. The varying means includes a first set of piston cavities with different cross-sectional areas and fixed elements with different cross-sectional areas, and a second set of pistons with different cross-sectional areas and a second set of pistons with different cross-sectional areas of the wave pistons. a second set of piston cavities, each piston of the second set of pistons being received in a piston cavity of the first set; Each cavity of the stone cavities is capable of accommodating each piston of the first set and includes means for selectively supplying selected pressure fluid to each cavity of the first and second sets of cavities. The digital hydraulic actuator described in item 8 of the scope of Eta. (10) The means for selectively supplying pressure supplies the first or second pressure to each cavity, and the first pressure and the second pressure are significantly different from each other. de Digital hydraulic actuator. (11) The digital hydraulic actuator according to claim 10, wherein the operating piston is a double-acting piston and is provided with means for supplying pressure fluid with the side of the operating piston facing away from the fluid coupling facing down. (12) The fluid coupling has a straight cylindrical passage connecting the first cylinder and the second cylinder, and the cross-sectional area of the passage is changed from a cross-sectional area equal to the first cylinder to a second cylinder. 11. A digital hydraulic cylinder according to claim 10, further comprising means for changing the cross-sectional area of the cylinder to be equal. (13) The first set of cylinders and the first set of pistons have a common axis, and the first set of pistons are separated to form the walls of each cavity of the first set of cavities. The digital hydraulic actuator according to claim 10. (14) The second set of cylinders and the second set of pistons have a common axis, and the second set of pistons are separated to form the walls of each cavity of the second set of cavities. The digital hydraulic actuator according to claim 10. (15) The fluid coupling has a straight cylindrical passage connecting the first cylinder and the second cylinder, and the cross-sectional area of the passage is changed from a cross-sectional area equal to that of the first cylinder to a cross-sectional area equal to that of the first cylinder. 12. A digital hydraulic cylinder according to claim 11, further comprising means for changing the cross-sectional area of the cylinder to be equal. (16) The first set of cylinders and the first set of pistons have a common axis, and the first set of pistons is separated from the first set of pistons. The digital camera according to claim 11 forming a wall of each cavity of the cavity. Tal hydraulic actuator. (17) The second set of cylinders and the second set of pistons have a common axis, and the second set of pistons are separated to form the walls of each cavity of the second set of cavities. The digital hydraulic actuator according to claim 11. (18) The first set of cylinders and the first piston have a common axis, and the first set of pistons are separated to form the walls of each cavity of the first set of cavities. The digital hydraulic actuator according to claim 12. (19) The second set of cylinders and the second set of pistons have a common axis, and the second set of pistons are separated to form the walls of each cavity of the second set of cavities. The digital hydraulic actuator according to claim 12. (20) The digital hydraulic actuator according to claim 8, wherein the working piston is a double-acting piston and is provided with means for supplying pressure fluid with the side of the working piston facing away from the fluid coupling facing down. (21) The digital hydraulic actuator according to claim 9, wherein the working piston is a double-acting piston and is provided with means for supplying pressure fluid with the side of the working piston facing away from the fluid coupling facing down. (22) The fluid coupling has a straight cylindrical passage connecting the first cylinder and the second cylinder, and the cross-sectional area of the passage is changed from the cross-sectional area equal to the first cylinder to the second cylinder. 9. A digital hydraulic cylinder according to claim 8, further comprising means for changing the cross-sectional area of the cylinder to be equal. (23) The fluid coupling has a straight cylindrical passage connecting the first cylinder and the second cylinder, and the cross-sectional area of the passage is changed from a cross-sectional area equal to the first cylinder to a second cylinder. 10. A digital hydraulic cylinder according to claim 9, further comprising means for changing the cross-sectional area of the cylinder to be equal. (24) a cylinder, a body having a first element, and a chamber connected together; a digital hydraulic actuator unit with a cylinder, the first element being a cylinder; a second element forming a piston within the cylinder, the first element and the second element cooperating. It has a pair of piston and cavity that act in the same way, and the cooperation between these piston and cavity is The same action forms a digital hydraulic actuator, and the piston The chamber is divided into a high pressure chamber and a low pressure chamber, and the piston is moved to the high pressure chamber side. A pressure difference is created between the hydraulic fluid filling the high pressure chamber and the low pressure chamber, and the main body is provided with a plurality of valves, one for each cavity, and the first passage means passing through the main body is provided with a plurality of valves, one for each cavity. a digital hydraulic actuator connecting each valve to the high pressure chamber by a second passage means in the body, connecting the low pressure chamber to each valve by a second passage means in the body, and connecting each cavity to the respective valve by a separate passage through the body. unit. (25) The actuator unit according to claim 24, wherein each valve is arranged symmetrically with respect to the axis of the device. (26) The actuator unit according to claim 25, further comprising means for connecting the cylinder to the hydraulic actuator in order to supply hydraulic fluid under pressure from the cylinder to one side of the hydraulic actuator. (27) The actuator unit according to claim 25, wherein the chamber and the cylinder are located at both axial ends of the main body. (28) The first passage means extends approximately along an axis passing through the shaft projecting into the chamber. The piston has a passageway extending along the shaft while maintaining a sealing relationship with the shaft. 26. The actuator unit according to claim 25, wherein the actuator unit is slidable along the shaft.