JPS6320208A - Nose-dive avoidance method in braking vehicle - Google Patents

Abstract

PURPOSE:To ensure the prevention of nose-dive at the time of braking by changing over a throttle valve to a secondary changeover position prohibiting the elongation of a hydraulic cylinder and giving a large damping force when a vehicle is in a predetermined brake condition. CONSTITUTION:A throttle valve 55 is changed over to a primary changeover position, thereby obtaining a predetermined damping force. Said throttle valve 55 is changed over to a secondary changeover position, when a vehicle is in a braked condition. In this case, a hydraulic cylinder 12 is allowed only to contract and a hydraulic fluid flow is so controlled as to give a damping force larger than available with the primary changeover position. According to the aforesaid constitution, hydraulic cylinders 10 and 12 at the front wheel side sink at a restricted sinking speed and hydraulic cylinders 16 and 18 at the rear wheel side are allowed to move toward a contracting direction only. According to the aforesaid constitution, it becomes possible to avoid the occurrence of a nose-dive phenomenon wherein the forward-down angle of a vehicle front is excessive.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a nose dive avoidance force method when braking a vehicle, particularly when braking a vehicle equipped with a hydraulic suspension device suitable for an I-rack crane or the like. Regarding how to avoid nose dive.

(Prior art and its problems) Truck cranes generally have outriggers that extend laterally from the chassis frame to ensure work stability during suspension work, and lift the entire vehicle body to lift tires, etc. off the ground. These are suspended from the chassis frame to increase the suspension load of the chassis frame.

At this time, in order to completely lift the tires off the ground, conventional trunk cranes use an axle.
Many are fixed types that are attached directly to the chassis frame without intervening springs.

In addition, even when the truck crane moves while suspending a heavy object such as a tetrapod, the axle of the truck crane is fixed to ensure stability during suspension.

However, if the axle is mounted in a fixed manner without intervening a spring, there is a problem in that the ride comfort during traveling of a vehicle such as a truck crane is extremely poor.

Therefore, in order to improve the riding comfort of vehicles such as truck cranes when moving, a hydraulic suspension device with a spring function and a shock absorber function is installed between the chassis frame and the axle, which improves the riding comfort when moving. However, since the crane and other components of vehicles such as truck cranes are mounted on the chassis frame, their center of gravity is relatively high, so if sudden braking is applied while moving, the front of the vehicle may sink. A problem arises in that a so-called "F nose dive" phenomenon occurs significantly.

The present invention has been made in order to solve such problems, and is a method for reliably preventing the so-called "nose dive" during braking of a vehicle such as a truck crane equipped with a hydraulic suspension device. The purpose is to provide a dive avoidance method.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the method for avoiding nose dive during vehicle braking according to the present invention provides a piston side chamber defined by a piston and a piston side chamber defined by a piston between a chassis frame and an axle. A hydraulic cylinder having a piston between two chambers on the other side and a chamber on the other side of the piston are interposed, the one side chamber of the piston and the other side chamber of the piston are communicated with each other through an oil passage, and a gas gas defined by a movable partition wall is provided in the middle of the oil passage. an accumulator that has a chamber and an oil chamber and stores a part of the hydraulic oil discharged from the chamber on one side of the piston in the oil chamber when the piston moves; throttle valve means having first and second switching positions, detecting a braking condition of the vehicle, and controlling the throttle valve means to contract and extend the hydraulic cylinder when the vehicle is in an unbraked condition; When the vehicle is in a predetermined braking state, extension of the hydraulic cylinder is prohibited, and contraction is prohibited. The second switching position provides a greater damping force than the first switching position.
When it is detected that the vehicle has changed from the predetermined braking state to the non-braking state, the switching position is switched from the second switching position to the first switching position after a predetermined time has elapsed from the time of detection. It is characterized by switching the position.

(Function) When the vehicle is not in a braking state, part of the hydraulic oil that flows in and out between the chamber on one side of the piston and the chamber on the other side of the piston when the hydraulic cylinder expands and contracts is stored in the oil chamber of the accumulator, and as the amount of stored oil increases or decreases, gas As the chamber contracts and expands, the pressure in the gas chamber increases or decreases, and as the pressure in the gas chamber increases or decreases, the operating oil pressure also increases or decreases, achieving a spring function. Then, by switching the throttle valve means having a throttle function to the first switching position where a predetermined damping force is obtained in response to contraction and expansion of the hydraulic cylinder, the flow rate of the hydraulic oil flowing through the oil passage is reduced. It is regulated and the shock absorber function is realized. - On the other hand, when the vehicle is in a braking condition, the throttle valve means is switched to the second switching position, the hydraulic cylinder is only allowed to retract, and the first
Since the flow of hydraulic oil is regulated to obtain a damping force greater than the switching position, the contraction of the hydraulic cylinder installed at the front of the vehicle is restricted, and the extreme sinking of the front of the vehicle is suppressed. , placed at the rear of the vehicle? Since the II+ pressure cylinder is prohibited from extending, the rear of the vehicle is prevented from lifting up, thereby avoiding an extreme nose dive phenomenon.Furthermore, when it is detected that the vehicle has changed from a braking state to a non-braking state, without switching the throttle valve means from the second switching position to the first switching position, and after a predetermined time has elapsed from the time of detection, that is, after the inertial force or reaction force has sufficiently disappeared, the throttle valve means is switched from the second switching position to the first switching position. By switching to , nose dive can be reliably prevented.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a hydraulic suspension device according to the present invention. !
A known crane 2 is mounted and fixed on the upper surface of a chassis frame 3 of an L-rack crane 1, and in FIG. Shows the folded state.

The trunk crane 1 shown in Fig. 1 has front and rear wheels.
The front wheels 4.4 are attached to both ends of a front axle (not shown), and the front axle has a front axle housing 5 with a substantially rectangular cross section disposed laterally below the front of the chassis frame 3. (Figure 2). Brackets 5b and 5c are protruded from the upper wall 5a of the front axle housing 5 near the left and right front wheels 4, 4, respectively, while brackets 5b and 5c are provided near the upper edge of each side wall 3a and 3b of the chassis frame 3, and )5
Brackets 3c and 3d are provided above the side walls 3a and 3h to project laterally and vertically, respectively. and,
Between these brackets 5b and 3c and the bracket 5c,
Hydraulic cylinder 1 for the left front wheel, details of which will be described later, are installed between 3d and 3d.
Hydraulic cylinders 12 for the 0 and right front wheels are attached, and these hydraulic cylinders 10.12 support the load applied to the front wheels 4, 4. The relative positional relationship between the chassis frame 3 and the front axle in the longitudinal direction of the vehicle is regulated by two radius rods 7a and 7b, each extending upward and downward.

The f & wheels 8.8 are attached to both ends of a rear axle (not shown) housed in a rear axle housing 9 disposed laterally below the rear of the chassis frame 3, and are attached to both ends of a rear axle (not shown) that is housed in a rear axle housing 9 disposed laterally below the rear of the chassis frame 3. Hydraulic cylinders 16.18 for left and right rear wheels are installed between the housing 9 and the side walls 3a (3b) of the chassis frame 3, and these hydraulic cylinders 16.18 support the vertical load applied to the rear wheels 8.8. The relative positional relationship between the chassis frame 3 and the rear axle in the longitudinal direction of the vehicle is regulated by two radius rods (not shown) on each side of the upper and lower sides.

Incidentally, reference numerals 13 and 14 in FIG. 1 indicate outriggers that protrude laterally to the left and right of the vehicle body to fix the vehicle body when the vehicle is stopped and suspended.

The hydraulic cylinders 10, 12, 16, 18 of the hydraulic suspension system that implements the method of the present invention have a spring function, a shock absorber function, an on-type function, an anti-nose dive function, a vehicle height adjustment function, etc. Details will be described later.

Next, referring to FIGS. 3 to 6, the hydraulic cylinder 1
The configuration of the hydraulic cylinders 10.12, 16.18, and the hydraulic pressure supply circuit that supplies hydraulic pressure to these hydraulic cylinders 10.12, 16.18, etc. will be explained.

Both the front wheel hydraulic cylinder 10.12 and the rear wheel hydraulic cylinder 16.18 have substantially the same configuration, and each hydraulic cylinder 10 (12, 16, 18) has a cylinder body 10a (12a, +6a, 18a). ) and the piston chamber of this cylinder body 10a (12a, 16a, 18a), and the piston chamber is connected to the upper chamber 10f (+2f, 16f).
, 18f) and lower chamber] Og (12g.

Piston 10b (12b) divided into 16g, 18g)
, 16h, IRh) and hydraulic circuit] Od (12d,
16d, 18d) and stroke sensor 10e (1
2e, 16e, 18e), and extends from the piston surface on the lower chamber]Og (12g, 16g, 18g) side of the piston chamber, and extends from the piston surface of the cylinder body 10a (12a, 16a,
18a) which protrudes outward from the piston rod 10c (
12c, 16c, 18c) are the piston 10b (12c)
b, 16b, 18b), and this piston rod IOc (12c, 16c, 18
c) The displacement amount is measured using the aforementioned stroke sensor 10e (12e).
, 16e, 18e) are detected. Stroke sensor l0e for each hydraulic cylinder 10 (+2.16.18)
(+2e, 16e, 18e) are electrically connected to an attitude control controller 120, which will be described later.

The hydraulic circuit portions of the hydraulic cylinders 0 (12, 16, 18) 0d (12d, 16d, 18d) are each constructed as shown in FIG.
16d, 18d) have 4 baud) PI, P2
．． PP and B are provided, one end of which is connected to the
i, and the other end is the piston lower chamber]Og (12g,
A parallel circuit consisting of a relief valve 25 and a flow control valve 26 consisting of a throttle 26a and a check valve 26b is disposed in the oil passage 21 communicating with A pilot switching valve 27 is disposed in the passage 21 .

The relief valve 25 has a piston lower chamber of 10 g (12 g).

16g, 18g) side toward the boat PI side exceeds a predetermined pressure, that is, when the piston speed of the piston 10b (12b, 16b, 18b) exceeds a predetermined value. , to distribute hydraulic oil. Further, as shown in FIG. 7, the check valve 26b is of a restrictor type in which the amount of movement of the poppet 260 is limited. More specifically, a valve chamber 261 having a larger diameter than these ports is formed between an inlet boat 263 and an outlet boat 264 of the check valve 26b, and the poppet 260 is slidably slidable in the axial direction in this valve chamber 261. The large diameter end face 26 of the poppet 260 is fitted in the valve chamber 261.
A spring 262 is housed between the 0b and the exposed boat 264 side. The spring 262 presses the poppet 260 in a direction in which the small diameter valve portion 260a of the poppet 260 comes into contact with the large mouth valve seat 263a of the valve chamber 261. Small diameter valve part 260
A through hole 260c is bored in the radial direction, and the through hole 260c is formed in the large diameter end surface 260b along the central axis.
A hole 260d communicating with is bored. A ring-shaped spacer 265 is provided within the valve chamber 261 in the stepped portion 264a, concentrically with the valve chamber 261 toward the poppet 260.

This poppet 260 allows the flow of hydraulic oil in the direction from the inlet boat 263 side to the outlet boat 264 side, that is, from the switching valve 27 side to the piston lower chamber 10 g (12 g).

16g, 18g) side, and when the oil pressure at the inlet port 263 exceeds the oil pressure at the outlet port side and the spring force of the spring 262, the poppet 260 closes the outlet of the valve chamber 261. Moving to the boat 264 side, the hydraulic oil flows through the inlet port 263, the gap between the valve seat 263a and the small diameter valve portion 2608, the through hole 260c, the hole 260d, and the outlet port 264. However, the spacer 265 provided in the valve chamber 261 restricts the amount of movement of the poppet 260, and the large diameter end surface 265 of the poppet 260
When the spacer 0b moves to the position where it comes into contact with the spacer 265, the gap between the valve seat 263a and the small diameter valve part 260a becomes maximum,
The flow rate of the hydraulic oil flowing through the check valve 26b is regulated by this maximum gap.

A pilot oil passage 24 communicating with the port PP is connected to the switching valve 27, and when pilot oil pressure is applied, the switching valve 27 opens to allow hydraulic oil to flow. One end is connected to the port) P2, and the other end is connected to the piston lower chamber 10g (12
A pilot check valve (second check valve) 28 is disposed in the oil passage 22 that communicates with the ports PP, 16g, 18g), and a pilot oil passage 24 that communicates with the port PP is connected to this check valve 28. When the pilot oil pressure does not act on the check valve 28, 10g (12g, 16g, 18g) of the piston lower chamber is released from the port P2 side.
Only the flow of hydraulic oil in the direction toward the side is allowed, and when the pilot oil pressure is applied, the flow in either direction is allowed. Figure 8 shows this pilot check valve 2.
8 is shown in more detail, the check valve 28 has a first valve chamber 281 and a second valve chamber 282 along the longitudinal center axis.
are formed, and the first valve chamber 281 has a small diameter portion 281.
a and a large diameter portion 281b. The first valve chamber 281 and the second valve chamber 282 communicate with each other through a passage 287 along the central axis, and an outlet boat 285 communicating with the first valve chamber 281 is provided in the center of one end surface 28a of the check valve 28. perforated, second
A pilot oil passage 284 bored from the other end surface 28b of the check valve 28 communicates with the valve chamber 282. The pilot oil passage 24 is connected to this pilot oil passage 284 . An inlet port 286 communicating with the passage 287 is bored at a substantially central position on the outer peripheral wall of the check valve 28 , and the inlet port 286 is connected to the oil passage 22 .

The first valve chamber 281 has a poppet 280 with a small diameter portion 281a.
is fitted so as to be slidable in the axial direction on the inner circumferential surface of the
The small diameter portion 281a of the valve chamber 281 accommodates the large diameter end face 280b of the valve 280 and the protruding boat 285 side. The spring 288 connects the small diameter valve portion 280a of the poppet 280 with the valve chamber 281 and the passage 287.
The poppet 280 is pressed in a direction in which it comes into contact with an inlet valve seat 287a formed in the section. A through hole 280c is bored in the small diameter valve part 280a of the poppet 1-280 in the radial direction, and a hole 280d communicating with the through hole 280c is bored in the large diameter end surface 280b of the poppet 280 along the central axis. has been done. Then, the outlet port 285 side step portion 28
5a, the valve chamber 2 is placed in the valve chamber 281 toward the poppet 280.
A ring-shaped spacer 289 is provided concentrically with 81.

A piston 283 is fitted into the second valve chamber 282, and a piston rond 283a formed on the piston surface of the poppet 280 of the screw 283 has an end surface that is similar to the poppet 280.
The valve chamber 28 is located opposite to the end face of the small diameter valve portion 280a.
2 to the passage 287 side.

When the pilot hydraulic pressure does not act on the piston 283 of the second valve chamber 282, if the hydraulic pressure supplied to the inlet boat 286 exceeds the hydraulic pressure acting on the large diameter end surface 280b of the poppet 280 and the pressing force of the spring 2BB, the poppet 280 When opened, this check valve 28 only allows hydraulic oil to flow from the inlet boat 286 to the outlet boat 285.

On the other hand, when the pilot oil pressure acts on the piston 283, the piston 283 moves toward the poppet 280, and its iron 283a pushes the poppet 280 against the spring force of the spring 288 and the differential pressure across the poppet 280 to the exit boat 285.
Pushing to the side, the poppet 280 is moved to the exit boat 285 side. As a result, the hydraulic oil is inlet boat 286,
Gap between valve seat 287a and small diameter valve part 280a, through hole 28
0c, flow from inlet boat 286 to outlet boat 285 via hole 280d and outlet port 285, and flow in the opposite direction are both permitted. However, due to the spacer 289 provided in the valve chamber 281, the valve chamber 281 is closed.

The amount of movement of the poppet 280 is regulated, and when the large-diameter end face 280b of the poppet 280 moves to a position where it abuts the spacer 289, the gap between the valve seat 287a and the small-diameter valve portion 280a becomes maximum, and the operation of flowing through the check valve 28 increases. The flow rate of oil will be regulated by this maximum gap.

An oil passage 23 is connected to the boat B of the hydraulic circuit section 10d (12d, 16d, 18d), and this oil passage 23 communicates with the oil passage 21 between the switching valve 27 and the boat hPI.

In the middle of this oil passage 23, a pyro-7 check valve 2 having the same function as the pilot check valve 28 is provided.
9 and a pilot-operated switching valve (second check valve) 30, the pilot oil passage 24 is connected to the check valve 29 and the switching valve 30, respectively. When no oil pressure is applied, the check valve 29 allows hydraulic oil to flow only in the direction from the boat 1-B side toward the boat P1 side, and when pilot oil pressure is applied, it allows flow in either direction. The switching valve 30 opens when pilot oil pressure is applied to allow the flow of hydraulic oil. Each hydraulic circuit section 10d (12d
, 16c+, 18d) are connected to the respective boats P1, and the boats PP are connected to a pilot oilway 51 which will be described later.

bow of the hydraulic circuit section 10d of the left front wheel hydraulic cylinder 10)
PI is connected to the outlet boat 47b of the electromagnetic switching valve 47 via the hydraulic pressure path 43, and is connected to the input port 4 of the electromagnetic switching valve 470.
7a is connected to an operating hydraulic pressure path 4, which will be described later. The hydraulic pressure path 43 includes a hydraulic pressure path 4 that branches off in the middle of the oil path.
4 is connected, and this hydraulic pressure path 44 is connected to the boat P1 of the hydraulic circuit portion 12d of the right front wheel hydraulic cylinder 12. A drain oil passage 48 is further connected to the hydraulic pressure passage 43 and branches in the middle of the oil passage, and the drain oil passage 48 is connected to the drain side via a relief valve 36. The hydraulic pressure path 4I is also connected to each input port 49a, 50a of the electromagnetic switching valves 49, 50, and each output port 49b, 50b of the electromagnetic switching valve 49.50 is connected to a hydraulic cylinder 16°18 for the left and right rear wheels. Hydraulic circuit section! 6d, +8
It is connected to each boat P1 of d via hydraulic pressure passages 45 and 46, respectively. The electromagnetic switching valves 47, 49.50 are both electrically connected to an attitude control controller 120, which will be described later, and when an energizing signal is supplied from the attitude control controller 120, these electromagnetic switching valves 47, 49, 50 open. to allow hydraulic oil flow.

The accumulator 5 is connected to the port P3 communicating with the piston upper chamber 10f of the left front hydraulic cylinder 10 through an oil passage 73.
7 is connected, and a biloft check valve 54 and a pilot check valve (
A flow control valve (parallel circuit) 55 consisting of a first check valve) 55a and a throttle 55b is provided, and an oil passage 73 between the flow control valve 55 and the check valve 54 is connected to port B of the hydraulic circuit section 10d. An oil passage 74 communicating with is connected.

The accumulator 57 is, for example, a bladder-shaped one, and the inside of the accumulator 57 is defined by a rubber bag 57a etc. into an oil chamber 57b and a gas chamber 57c.The oil chamber 57b is communicated with an oil passage 73, and the gas chamber 57c is filled with high pressure N2 gas. A pilot oil passage 5I, which will be described later, is connected to a biloft check valve 55a of the flow rate control valve 55, and a pilot oil passage 52, which will be described later, is connected to the pilot check valve 54. When pilot oil pressure does not act on these check valves 54 and 55, only the flow of hydraulic oil is allowed from the accumulator 57 side toward the piston upper chamber 10f side, and when biloft oil pressure acts on it, flow in either direction is allowed. Permissible.

An accumulator 6 is connected to a port P3 communicating with the piston upper chamber 12f of the right front wheel hydraulic cylinder I2 through an oil passage 75.
2 is connected, and a pilot check valve 59 and a pilot check valve (
A flow control valve (parallel circuit) 60 consisting of a first check valve) 60a and a throttle 60b is provided, and an oil passage 75 between the flow control valve 60 and the check valve 59 is connected to port B of the hydraulic circuit section 12d. nirenif! An oil passage 76 is connected thereto.

The accumulator 62 is a bladder type similar to the accumulator 57, and the pilot check valve 60
A pilot oil passage 51, which will be described later, is connected to a, and a pilot oil passage 52, which will be described later, is connected to the pilot check valve 59. When pilot oil pressure does not act on these check valves 59 and 60, only the flow of hydraulic oil is allowed from the accumulator 62 side toward the piston upper chamber 12f side, and when pilot oil pressure acts on them, flow in either direction is allowed. Permissible.

Piston upper chamber 1 of hydraulic cylinder 16.18 for left and right rear wheels
Each port P3 communicating with 6f and 18f has an oil passage 77, respectively.
．． Accumulators 65 and 68 similar to the accumulator 57 are connected through the oil passage 79, and a biloft check valve 64 (67) is disposed in the middle of the oil passage 77 (79), and the check valve 64 (67) and the accumulator 65 ( 68
) between the oil passages 77 (79) include the hydraulic circuit section 16d.
The drain oil passage 77a (79a) is connected to the oil passage 7B (80) which communicates with port (18d) B, and also communicates with the drain side via the relief valve 37 (38).
is connected. The pilot check valve 64 (6
7) is connected to a pilot oil passage 52, which will be described later. When the pilot oil pressure does not act on this check valve 64 (67), the piston upper chamber 16f (18f
) only is allowed to flow in the direction of hydraulic oil, and when pilot oil pressure is applied, flow in either direction is allowed.

FIG. 5 shows a hydraulic pressure supply system, and reference numeral 102 is a spring center electromagnetically operated four-bottom, three-position switching valve equipped with solenoids 102a and 102b-t at both ends, and the operating hydraulic path 41 is a solenoid switching valve. 102, and an operating hydraulic path 41a communicating with the hydraulic pump 100a is connected to the port 102d. port 1'0
2e and 102f are both connected to the drain side. The suction side of the hydraulic pump 100a is an oil passage 41b.
It is connected to a filter 101 installed in the drain tank 91 and immersed in hydraulic oil. A throttle 103a and a check valve 103b are provided in the middle of the hydraulic pressure path 41.
A flow control valve 103 consisting of the following is provided. The switch valve 103b connects the hydraulic pump 100a to the electromagnetic switching valve 10.
This allows only the flow of hydraulic oil discharged through 2 in the downstream direction.

The solenoid 1.02a of the electromagnetic switching valve 102.

102b is electrically connected to the attitude control controller 120 which is installed later, and the solenoids 102a and 102
When both of b are in the de-energized state, the electromagnetic switching valve 102 is switched to the neutral position 102B, and the hydraulic pressure path 41a and the hydraulic pressure path 41 on the discharge side of the hydraulic pump 100a are cut off.
The hydraulic pressure path 41a is connected to the drain side. When the solenoid 102a is energized, the electromagnetic switching valve 102 is switched to the open position 102A, and the hydraulic pressure path 41a and the hydraulic pressure path 41 are connected. When the solenoid 102b is energized, the electromagnetic switching valve 102 is switched to the drain position 102C, and the hydraulic pressure path 41 is connected to the drain side, so that the hydraulic fluid in the hydraulic pressure path 41 is discharged to the drain tank 91.

Hydraulic pump] A drain oil passage 1 is connected to the hydraulic pressure passage 41a between the OOa and the electromagnetic switching valve 102 and communicates with the inside of the drain tank 91 via a relief valve 107 and a filter 106.
11 is branched, the relief valve 1.07 is discharged from the hydraulic pump 100a, and the hydraulic cylinders 10.12, 16
．． The hydraulic pressure supplied to 18 etc. is regulated to a predetermined value.

Reference numeral 105 in FIG. 5 is a four-boat electromagnetic switching valve that is switched to two positions by a solenoid 05a.
However, a pilot oil passage 51a communicating with the oil passage 41b is connected to the boat 105C via a hydraulic pump OOb,
Bo HO5d and 105e are connected to the drain side, respectively.

The solenoid 105a is electrically connected to the attitude control controller 120, and the electromagnetic switching valve 105 controls the boat 105b, the boat 105C1, the boat 105d, and the boat 05e, respectively, when an energizing signal is not supplied from the attitude controller 120. The pilot pressure oil discharged from the hydraulic pump 100b is connected to the oil passage 51a and the electromagnetic switching valve 1.
05 to the pilot oil path 51, and when the I/NJ force signal is supplied from the attitude control controller 120, the boat 105b, the boat 105e, and the boat 10
5C and 105d are respectively connected, the pilot oil passage 51 communicates with the drain tank 91, and the pilot pressure oil in the pilot oil passage 51 is returned to the drain tank 91.

The hydraulic pumps 100a and 100h are both internal combustion engines (E/G) 110 mounted on a truck crane.
Driven by.

Returning to FIG. 3, the pilot oil passage 52 is connected to the check valve 7.
0 to the pilot oil passage 51, and to the hydraulic pressure passage 41 between the flow rate control valve 103 and the electromagnetic switching valve 47 via a check valve 71. The check valve 71 allows only the pilot pressure oil to flow in the direction toward the passage 52, and the check valve 71 only allows the pilot pressure oil to flow in the direction from the hydraulic pressure passage 41 to the pilot oil passage 52.

FIG. 6 shows the operation of the hydraulic suspension device according to the present invention?
til + attitude control controller] 20,
Each input terminal 120a to 1 of attitude control controller +20
20d includes the stroke sensors 10e, 12e,
16e.

18e are connected to each other. This stroke sensor 10e
(+2e, 16e, 18e) is the piston rod 1oc (12c).

A magnetic sensor reads the magnetic scale engraved on the surface of Biston Rono 1 River Oc (12c, 18c).
16c.

18c) is a non-contact type that counts the displacement amount (stroke ■) of each stroke sensor]De(12e, 1
6e.

18e) detected the piston rotor F10c (12c, 1
6c, Hlc) (7)7. )l': The I-return amount signal is supplied to the attitude control controller 7]20.

A tilt angle sensor 4+122 is connected to the input terminal 120e. This (approximately) the bevel angle sensor 122 is
It is attached at an appropriate position to detect the tilt angle θ of the vehicle body in the left-right direction, and the detected tilt angle No. 48 is supplied to the attitude control controller 120.

A brake pressure switch 125 is electrically connected to the input terminal 120f, and the brake pressure switch +25 is disposed in the middle of the brake duplex 128, and when the brake operating oil pressure becomes a predetermined pressure or higher, the ON signal is used for attitude control. is supplied to the controller 120. In addition, the code 126 is a brake pedal,
127 is a mask cylinder; mask cylinder] 27
The brake tube 128 is connected to the brake tube 128.

A vertical acceleration (G) sensor 124 is electrically connected to the input terminal 120j, and this vertical acceleration (G) sensor 124 is also attached to an appropriate position on the chassis frame 3.
Changes in the sinking speed or lifting speed of the vehicle body over time are detected, and these detected values are set to predetermined values (for example, ±0.2G).
, provided that the vibration period is 2 Hz or less), respective predetermined signals are supplied to the attitude control controller 120.

Various switches 130 are connected to the input terminals 120g to 1201.
, 132, and 134 are connected to each other, and these switches transmit the vehicle attitude control command signal to the attitude control controller 120.
The manual changeover switch 134 is a two-position changeover switch between manual mode and auto mode, and is switched to the manual mode position (on position). When the plane is switched to any of the neutral, very low gear, and 1st gear switching positions (i.e., when the vehicle is stopped or traveling at a low speed below a predetermined speed), the attitude control command Signal input becomes possible. The attitude control switch 130 generates a command signal to tilt the vehicle body forward and backward, left and right, and when the lever 130a is tilted in the longitudinal direction of the vehicle body, it generates a command signal to tilt the vehicle body in the longitudinal direction according to the tilt angle, and the lever When 130a is tilted in the horizontal and horizontal directions of the vehicle body, a command signal is generated to tilt the vehicle body in the horizontal and horizontal directions according to the tilt angle, and the command signal is supplied to the posture control controller 120. Further, the vertical control switch 132 generates a command signal to move the vehicle body up and down while maintaining the horizontal state, and when the lever 132a is tilted in the longitudinal direction of the vehicle body, a command signal is generated to raise and lower the vehicle body according to the tilt angle. is generated and the command signal is supplied to the attitude control controller 120.

The output terminal 120k of the attitude control controller 120 is connected to the solenoid 105k of the electromagnetic switching valve 105, and the output terminals 120m to 120p are connected to the electromagnetic switching valve 47°49.5.
0, output terminals 120r and 120s are connected to the solenoids 102a and 102b of the electromagnetic switching valve 102, respectively, and the attitude control controller 120 supplies drive signals to these electromagnetic switching valves.

Next, a method for controlling the operation of the hydraulic suspension device configured as described above will be explained.

The hydraulic suspension device includes an attitude control controller 12
0 is operated by executing a predetermined control program to be described later, and this operation control includes the inclination angle sensor 122, the vertical acceleration (G) sensor 124, and the brake pressure switch 125 when the truck crane 1 is traveling. ,
Stroke sensor 10e (12e, 16e, 18e
) is automatically executed in response to a detection signal (this is referred to as "driving control"), and the operator operates the manual changeover switch when the vehicle is stopped or the crane is suspended when the crane is running at a low speed below a predetermined speed. 134, by operating the posture control switch 130 and the vertical control switch 132, command signals are sent to the posture control controller 120.
(This is called "suspension control").The former control includes driving suspension mode control, anti-22nd dive control during braking, angle control, and level adjustment. The latter includes on-tire control, attitude control, and vehicle height control. The operation control of each of these modes will be explained in detail below with reference to the operation control programs shown in FIGS. 9 to 15.

(Hereinafter, this page margin) First, the posture control controller 120 executes step 200 shown in FIG. 9, and determines whether the manual changeover switch 134 is off, that is, whether it is in the auto mode position. If the result of this determination is affirmative (YES), the process proceeds to step 20 to release the suspension lock circuit, which will be described later. That is, the attitude control controller 120 does not output an energizing signal to any of the electromagnetic switching valves (47, 49, 50, 102, 105), and in this case, the hydraulic circuit shown in FIGS. A circuit for mode control is formed. Note that the attitude control controller 120 is the ninth
The steps shown in FIGS. 14 to 14 are sequentially executed, and if the determination result in each determination step is affirmative, the circuit for controlling the travel suspension mode is continuously formed and maintained.

Part of this travel suspension mode control is to add a spring function and shock absorber function to the hydraulic suspension system. It is. In FIG. 16, the solenoids 102a and 102 of the electromagnetic switching valve 102 are shown as described above.
Since both valves b are deenergized, the electromagnetic switching valve 102 is switched to the neutral position 1Y102B, and therefore the hydraulic oil from the hydraulic pump 100a is not discharged and supplied to the hydraulic pressure path 41, but is returned to the drain tank 91. On the other hand, since the solenoid 105a of the electromagnetic switching valve 105 is deenergized, the oil passage 51a and the pilot oil passage 51 are connected, and the pilot pressure oil from the hydraulic pump l00b is supplied to the pilot oil passage 51.
1 and the pilot oil passage 52 to the pilot check valves 28, 54, etc., and these pilot check valves 28, 54, etc. are opened. At this time, the relief valve 10B is in a relief state, whereby the pilot oil pressure is maintained at a predetermined constant value.

Solenoid switching valve 47, 49, 50, 102. and 105 are controlled in the manner described above, thereby forming the closed circuits shown in FIGS. 17 and 18, respectively, as the front wheel side and rear wheel side hydraulic circuits in the traveling suspension mode control. In addition, the states in which the pilot check valves 28, 54, etc. in FIGS. 17 and 18 are open are shown with broken lines, and the operating states of the switching valves 27, 30, etc. are shown in the drawings in their switching positions. In addition, the flow directions of the hydraulic oil and pilot pressure oil are shown by arrows (the same applies below).

The piston 10b (12b, 16b, 18b) of each hydraulic cylinder 10 (12, 1, 6, 18) has a piston rod 10c (12c
, +6c, 18c), the reaction force of the load (self weight) of the crane 2 etc. mounted on the chassis frame 3 and the load of the suspended object suspended by the crane 2, and the 10 g of the piston lower chamber.
(12g, 16g, 18g) The resultant force with the hydraulic oil pressure acting on the piston surface acts in the direction of pushing down the piston upper chamber 10r (12f).

16f, 18f) side piston surface, and the force pushing up and pushing down these pistons is balanced, causing the piston Ob (12b.

16b, 18b) are stationary in their equilibrium positions.

Now, connect the piston 10b via the piston rod 10c.
If the force (reaction force) pushing up in one direction increases and the above-mentioned equilibrium state is disrupted, and the piston IOb is displaced in the direction in which the hydraulic cylinder 1o contracts, hydraulic oil will be discharged from the two pistons 10f. The hydraulic oil flows through the path shown by the solid line arrow in FIG.
The screw I/
flows into the lower chamber 10g. However, the amount of hydraulic oil discharged from the piston upper chamber] is 10g in the lower piston chamber.
The amount of hydraulic oil that flows into the piston

The volume is reduced by the volume removed by the rod 10c, and therefore a portion of the hydraulic oil discharged from the piston upper chamber 10f flows into the accumulator 57 and compresses the gas chamber 57C. Then, the internal pressure of the accumulator 57 increases, and as a result, the hydraulic pressure acting on the two pistons 10f and the lower piston chamber 10g also rises, and the piston Job reaches a new equilibrium position where the increased reaction force and hydraulic pressure are balanced. It becomes seven when it comes to rest.

Conversely, if the reaction force pushing the piston 10b upward decreases and the equilibrium state collapses, and the piston 10b is displaced in the direction in which the hydraulic cylinder 10 extends, the hydraulic fluid
The path shown by the dashed arrow in Figure 7, that is, the piston lower chamber 10
From g, the throttle 26a of the flow control valve 26 of the oil passage 21 and the switching valve 27, and the opened pilot check valve 2 of the oil passage 22.
8. A parallel circuit consisting of the pilot check valve 29 and the pilot operation switching valve 30, the oil passage 74, and the piston upper chamber 10 through the pilot check valve 54 with the oil passage 73 opened.
flows into f. In this case, since the amount of hydraulic oil sucked into the upper piston chamber 10f is larger than the amount of hydraulic oil discharged from the lower piston chamber 10g, the insufficient hydraulic oil is replenished from the accumulator 57, and the oil chamber 57b of the accumulator 57
The volume of the gas chamber increases by an amount corresponding to the decrease in hydraulic oil, and the internal pressure of the accumulator 57 decreases. As a result, the hydraulic pressure acting on the upper piston chamber 10f and the lower chamber 10g also decreases, and the piston Ob comes to rest at a new equilibrium position where the decreased reaction force and decreased hydraulic pressure are balanced.

As mentioned above, the hydraulic circuits shown in FIGS. 17 and 18 are closed circuits, and therefore the piston upper chamber ]Of and the piston lower chamber 10g are cut off from the drain tank 91, so that no dust can enter these hydraulic circuits from the drain tank 91. There is less risk of inhalation of oil, etc., and the oil circulation to the piston upper chamber 10f becomes faster when the hydraulic cylinder 10 is extended.

Note that the pilot check valve 28 with the above-mentioned throttle function disposed in the oil passage 22 and the throttle 26a of the flow control valve 26 disposed in the oil passage 21 have a damping effect by restricting the flow of hydraulic oil. , when the piston 10b is displaced to the extension side, the flow is blocked by the check valve 26b of the flow rate control valve 26, so that the flow from the piston lower chamber log to the piston upper chamber 10
The hydraulic fluid flowing toward the piston 10 flows through the pilot check valve 28 and the throttle 26-a.
When b is displaced to the contraction side, the hydraulic oil flows to the check valve 26.
A large damping force can be obtained by the amount that does not flow through b.

In addition, as shown in FIG. 19, when the hydraulic oil flows from the piston lower chamber 10g side to the piston upper chamber 10f side only through the pilot check valve 28 and the restrictor 26a, as the piston speed of the piston 10b increases. However, the damping force also increases at an approximately constant rate (in the jl area ZA of Fig. 19).
When the piston speed exceeds a predetermined value (increase in damping force in The damping force can be made substantially constant in the region where the value exceeds the predetermined value (region zll' in FIG. 19). This prevents excessive damping force from occurring in areas where the piston speed is high, eliminates the risk of vibration occurring in the type, and improves ride comfort.

The above-mentioned action is similar to the other hydraulic cylinders 12, 16, and 18, and the action on the rear wheel side hydraulic circuit can be easily estimated from the circuit diagram shown in FIG. 18, which is similar to FIG. The explanation will be omitted.

In addition, if high pressure is generated in the above-mentioned closed circuit due to overtaking while driving on rough terrain, etc., the relief valve 36 in the front wheel side hydraulic circuit shown in FIG. In the hydraulic circuit, relief valve 37 (38)
This allows some of the hydraulic oil to escape to the drain side.

Thus, each hydraulic cylinder 10,
12, 16.18 can expand and contract each hydraulic cylinder 10, 12, 16.18 according to the increase or decrease of the load to support the load at the above-mentioned equilibrium position and alleviate shocks and vibrations when driving on rough terrain etc. I can do it.

In addition, accumulators 57 (62) and 65 (for the front and rear wheels)
By appropriately setting the capacity of the gas chamber (57c), filling gas pressure, etc., it is possible to accommodate front axles 5 and rear axles 9 with various axle load distribution ratios.

Furthermore, if the amount of expansion/contraction (stroke amount) of the hydraulic cylinders 10, 12, 16, 18 is out of the specified value range, the hydraulic cylinder 1
Level adjustment control, which will be described later, is executed so that the stroke amounts of 0, 12, and 16.18 are maintained within the specified value range.

Next, returning to FIG. 9, in step 202, the attitude control controller 120 performs the rotation sensor 10e (
+2e, 16e, 18e) detected extension amount (stroke amount) of each hydraulic cylinder 10, 12.16.18
I-A, L-Il.

Lc and I-o are read, and then the arithmetic mean value LAB (-% x (LA+LB)) of the stroke (2) of the left and right front wheels is calculated and stored (step 203). This average value 1-AB
means the stroke amount at the center position of the front axle, and this stroke amount average value I,
This is to make it easier to control the vehicle horizontally in response to the fact that only one is used to perform these controls at the same time. In addition, each stroke amount 1-A, L
[1, L C+ r-n may be read when the detected value continues to be the same value for a predetermined period of time (e.g., 5 seconds), or may be read after a predetermined period of time (e.g., 1 second). The read value may be the average value of the detected values detected a predetermined number of times.

The attitude control controller 120 has the above-mentioned stroke value I,
The level adjustment control shown in FIGS. 10 to 12 is executed based on □, Lc, and Lb.

The posture control controller 120 first determines whether the stroke value ■-□ is within a predetermined range p±δ (step 210 and 215). The stroke amount β indicates the standard stroke amount of each hydraulic cylinder 10 and 12, and the δ amount is set to a minute @ (for example, 4 mm), and therefore falls within the specified range β.
±δ indicates a range in which if the detected stroke amount is within this range, it can be considered as substantially the reference stroke amount. The stroke value LAB is within the predetermined range p±
If it is within δ (if both the determination results in steps 210 and 215 are affirmative), there is no need to adjust the level of the hydraulic cylinders 10 and 12, and the first operation can be performed without performing any operation control on these cylinders. The process proceeds to step 220 shown in FIG.

On the other hand, when the stroke value LAn is smaller than the lower limit value (p-δ) of the predetermined range (if the determination result in step 210 is negative (No)), the attitude control controller 12
0 executes steps 211 and 212 and switches the electromagnetic switching valve 1.
An energizing signal is output to the solenoid 102a of 02 and the solenoid of the electromagnetic switching valve 47 to cause the electromagnetic switching valve 102 to switch to the open position 102A, and also to switch the electromagnetic switching valve 47 to the open position. And stroke sensor 10e
and step 213) to monitor the detection value signal of 12e.
The stroke value T-All is substantially equal to the upper limit value (l+δ
) is repeated until the above steps 211 and 212 are equal to . If the stroke value LAIl is below the lower limit value (7+-δ) of the specified range, it also means that there is a possibility that the hydraulic fluid in the hydraulic circuit is leaking. ” Two-limit value (p+δ)
The hydraulic cylinders 10 and 12 are extended until . When the stroke value LAB becomes substantially equal to the upper limit value (l+δ), step 210 is executed again, and the stroke value 1-Al1 becomes less than or equal to the lower limit value (1-δ) of the predetermined range. After confirming the above, the process proceeds to the subsequent step 215.

Figures 20 to 22 show step 2) 1 and 2.
] 2 is shown, first, the solenoid of the electromagnetic switching valve 105 shown in FIG. 20 remains deenergized as in FIG. The valve 10B is in a relief state and the pilot oil pressure is maintained at a predetermined constant value. on the other hand,
An energizing signal is supplied from the attitude control controller 20 to the solenoid 102a, and the electromagnetic switching valve 102 is moved to the open position 102.
Switching to A is in progress. At this time, the boats 102c and 102d of the electromagnetic switching valve 102 are connected, and the hydraulic pressure path 41 and the oil path 41a are communicated with each other. As a result, pump 1
Hydraulic oil is discharged from 00a to the hydraulic pressure path 41, and the hydraulic pressure B41 is increased by the action of the relief valve 107 in the relief state.
The hydraulic pressure supplied to the pump is maintained at a predetermined constant value.

The attitude control controller 120 supplies an energizing signal to only the electromagnetic switching valve 47 for front width among the switching valves connected to the hydraulic pressure path 41 shown in FIG. 21 to open it;
The other electromagnetic switching valves 49, 50 are held closed.

Therefore, the hydraulic fluid discharged to the hydraulic pressure path 41 is transferred to the hydraulic cylinder 10 through the flow rate control valve 103 and the electromagnetic switching valve 47.
12 hydraulic circuit sections 10d and 12d) are supplied to the PI.

The pilot oil pressure from the hydraulic pump 100b is supplied to the hydraulic circuit section 10d via a pilot oil passage 51.

Pilot check valves 55a and 6 of each boat pp of 12d, 16d, and 18d, and flow rate control valves 55 and 60
0a, respectively. Further, the pilot oil pressure is branched from the hydraulic pressure path 41 and is also generated in the pilot oil path 52 via the valve 71. Furthermore, the hydraulic pressure in the hydraulic pressure path 41 is set higher than the pilot oil pressure in the pilot oil path 52. ), the pilot oil pressure is supplied to each of the pilot check valves 54, 59, 64, 67 via the pilot oil passage 52.

A hydraulic circuit shown in FIG. 18 is formed in the hydraulic cylinders 16 and 1 on the rear wheel side, and their operation is controlled in the same manner as the traveling suspension mode control described above. On the other hand, a hydraulic circuit shown in FIG. 22 is formed in the hydraulic cylinders 10 and 12 on the front wheel side, and this hydraulic circuit is filled and replenished with hydraulic oil via the boat P1. Front left wheel hydraulic cylinder 10
The hydraulic oil supplied to the hydraulic circuit is routed through the route shown by the arrow in FIG. 22, namely, the pilot check valve 29 and the switching valve 30
It flows into the piston upper chamber 10f through the opened pilot check valve 54 of the oil passage 74 and the oil passage 73, and also flows into the accumulator 57 to increase the working oil pressure and push down the piston 10b. (Extend the hydraulic cylinder 10). At this time, a part of the hydraulic oil in the piston lower chamber 10g is discharged to the piston upper chamber 10f through the same path as the path indicated by the dashed arrow in FIG. 17 described above. The hydraulic oil supplied to the hydraulic circuit of the hydraulic cylinder 12 of the front right wheel also flows into the piston upper chamber 12f, as described above, and pushes the piston 12b downward.

In this way, the hydraulic cylinders 10 and 12 on the front wheel side extend in the direction in which the stroke amount increases, and the stroke NLA
Hydraulic oil is supplied to each hydraulic cylinder 10 and 12 until ll becomes equal to the upper limit value (l+δ).

Return to step 215 in Fig. 10 and stroke value ■7□
is larger than the upper limit value (7!10δ) of the predetermined range (if the determination result in step 215 is negative), the attitude control controller 120 executes steps 216 and 217 to control the solenoid 102b of the electromagnetic switching valve 102. An energizing signal is output to the solenoid of the electromagnetic switching valve 47, respectively, so that the electromagnetic switching valve 102 is switched to the drain position W 102 C, and the electromagnetic switching valve 47 is also switched to the open position. Then, the detection value signals of the stroke sensors 10e and 12e are monitored (step 218), and the stroke value LAI
Steps 216 and 217 are repeatedly performed until I becomes substantially equal to the upper limit (Il+δ). When the stroke value LAB becomes substantially equal to the upper limit value (l+δ), the step 215 is executed again, and it is confirmed that the stroke value L□ is equal to or less than the upper limit value (!L+δ) of the predetermined range. The process then proceeds to step 220 shown in FIG.

FIGS. 23 to 25 show steps 216 and 217.
The hydraulic circuit formed by the execution of
The electromagnetic switching valve 105 shown in the figure is in the deenergized open state as in FIG. 16, the relief valve 108 is in the relief state, and the pilot oil pressure is maintained at a predetermined constant value. On the other hand, the electromagnetic switching valve 102 is switched to the drain position 102C by supplying an energizing signal to the solenoid 102b from the attitude control controller 120. At this time,
Boat 102C and boat 102f of electromagnetic switching valve 102 are connected, boat 02d and boat 102e are connected,
Both the hydraulic pressure path 41 and the oil path 41a communicate with the drain tank 91 side. As a result, the hydraulic oil from the pump 100a is no longer discharged into the hydraulic pressure path 41, and conversely,
Hydraulic oil is discharged from the hydraulic cylinders 10 and 12 to a drain tank 91.

The attitude control controller 120 supplies an energizing signal to only the electromagnetic switching valve 47 for the front wheels to open it among the electromagnetic switching valves connected to the hydraulic pressure path 41 shown in FIG. Hold valves 49,50 closed. Therefore, as will be described later, the hydraulic fluid discharged to the hydraulic pressure paths 43 and 44 connected to the hydraulic circuit parts IQd and +2d of the hydraulic cylinders 10 and 12 is connected to the electromagnetic switching valve 47.
, hydraulic pressure path 4I, throttle 103a of flow control valve 103,
It is discharged to the drain tank 91 via the electromagnetic switching valve 102. The pilot oil pressure from the hydraulic pump 100b is transmitted through the pilot oil passage 51 to the hydraulic circuit section ]Od, 1
2d, 16d, 18d boats pp.

and pilot check valve 55 of flow control valve 55.60
a and 60a, respectively. Further, the pilot oil pressure is branched from the pilot oil passage 51 and is also generated in the pilot oil passage 52 via the check valve 70, and is also generated in the pilot oil passage 52 via the pilot oil passage 52.
4.67 each.

A hydraulic circuit shown in FIG. 18 is formed in the hydraulic cylinders 16 and 18 on the rear wheel side, and their operation is controlled in the same manner as the traveling suspension mode control described above. On the other hand, the hydraulic cylinders 10 and 12 on the front wheel side form a hydraulic circuit shown in FIG. 25, and when the electromagnetic switching valve 47 is opened, the hydraulic fluid in the hydraulic circuit shown in FIG. Discharged at .44.

The hydraulic oil discharged from the hydraulic circuit of the hydraulic cylinder 10 of the front left wheel follows the path shown by the arrow in FIG.
4, a parallel circuit consisting of a pilot check valve 29 and a switching valve 30, and a bow I/gate, and are discharged to the hydraulic pressure path 43. At this time, a part of the hydraulic oil in the accumulator 57 also flows out, lowering the hydraulic pressure, and as a result, the hydraulic pressure in the piston upper chamber 10f decreases, causing the piston 10b to move upward (the hydraulic cylinder 10 contracts). piston]
Due to the movement of Ob, a portion of the hydraulic oil is replenished into the piston lower chamber 10g along the same route as the solid arrow in FIG. 17.

The hydraulic oil discharged from the hydraulic circuit of the hydraulic cylinder 12 of the right front wheel also flows from the piston upper chamber 12f to the oil passage 44 as described in -.
The piston 12b moves in the direction (the hydraulic cylinder 12 contracts). And oil passages 43 and 44
As described above, the hydraulic fluid discharged into the drain tank 9 is passed through the opened electromagnetic switching valve 47, the hydraulic pressure path 41, the throttle 103a of the flow control valve 103, and the electromagnetic switching valve 102.
It is discharged into I.

At this time, the flow rate of the discharged hydraulic oil is regulated by the throttle 103a of the flow control valve 103, so the hydraulic oil in the hydraulic cylinder 10.12 on the front wheel side is gradually discharged, and the stroke amount of the hydraulic cylinder 10.12 is gradually shrinks in the direction of decrease, and the stroke amount L A It reaches the upper limit value (
7! +δ) for each hydraulic cylinder 10 and 1 until equal to
2 hydraulic oil will be discharged.

Returning to FIG. 11, the attitude control controller 120 now determines whether the detected stroke value Lc of the left rear wheel hydraulic cylinder 16 is within a predetermined range l±δ (steps 220 and 225).

The stroke amount l indicates the standard stroke amount of the hydraulic cylinder 16, and the specified range l±δ means that if the detected stroke amount is within this range, the stroke amount of the hydraulic cylinder 16 substantially corresponds to the predetermined reference stroke. Indicates the range that can be considered as a quantity. If the stroke detection value LC is within the predetermined range p±δ (if the determination results in both steps 220 and 225 are positive), there is no need to adjust the level of the hydraulic cylinder 16, and no adjustment is made to the hydraulic cylinder 16. The process proceeds to step 230 shown in FIG. 12 without performing any operational control.

On the other hand, when the stroke detection value Lc is smaller than the lower limit value (7!-δ) of the predetermined range (if the determination result in step 220 is negative), the attitude control controller 120 executes steps 221 and 222 to Switching valve 102
An energizing signal is output to the solenoid 102a of the solenoid 102a and the solenoid of the electromagnetic switching valve 49, respectively, so that the electromagnetic switching valve 102 is switched to the open position 1028, and the electromagnetic switching valve 49 is also switched to the open position. And stroke sensor 16e
The detected value signal of step 223) is monitored until the stroke detected value signal becomes substantially equal to the upper limit value (l+δ) for the same reason as described above.
Repeat step 22. When the stroke detection value Lc is substantially equal to the upper limit value B+δ), the step 220 is executed again, and it is confirmed that the stroke detection value Lc is equal to or higher than the lower limit value (l−δ) of the predetermined range. The process then proceeds to the subsequent step 225.

FIG. 20, FIG. 26, and FIG. 27 show the step 22 shown in FIG.
1 and 222;
The electromagnetic switching valve 105 and the electromagnetic switching valve 102 are switched to the switching positions as described above in FIG. be done.

The attitude control controller 120 supplies an energizing signal to only the electromagnetic switching valve 49 for the left rear wheel to open it among the electromagnetic switching valves connected to the hydraulic pressure path 4I shown in FIG. Keep the switching valve 47.50 closed. Therefore, the hydraulic oil discharged to the hydraulic pressure path 41 is transferred to the flow control valve 1.
03, the hydraulic circuit portion 16d of the hydraulic cylinder 16 is supplied to the boat P1 via the electromagnetic switching valve 49. And each boat PP of the hydraulic circuit parts 10d, 12d, 16d, 18d,
and pilot check valve 55 of flow control valve 55.60
a and 60a1 and pilot check valves 54, 59
．． Pilot oil pressure is supplied to each of 64 and 67.

The hydraulic cylinders 10 and 12 for the front wheels are formed with the hydraulic circuit shown in FIG. 17, and the hydraulic cylinder 18 for the right rear wheel is formed with the hydraulic circuit shown in FIG. 18. The operation of each hydraulic cylinder is controlled in the same manner as the travel suspension mode control described above. On the other hand, the hydraulic cylinder 16 on the left rear wheel side has a hydraulic circuit shown in FIG. 27 formed therein, and the hydraulic circuit is filled and replenished with hydraulic oil via a PI. Then, the replenished hydraulic oil is in the 27th
The path indicated by the arrow in the figure, i.e. the pilot check valve 29
It flows into the piston upper chamber 16f through the parallel circuit consisting of the electromagnetic switching valve 30, the oil passage 78, and the biloft checker valve 64 in which the oil passage 77 is opened, and the accumulator 65.
The hydraulic pressure also flows into the hydraulic cylinder, increasing the hydraulic pressure, and pushing down the piston 16b (extending the hydraulic cylinder 16). At this time, a part of the hydraulic oil in the piston lower chamber 16g is discharged to the piston upper chamber 16f along the same path as the path indicated by the dashed arrow in FIG. 18 described above. In this way, the hydraulic cylinder 16 on the left rear wheel side extends in the direction in which its stroke amount increases, and hydraulic oil is supplied to the hydraulic cylinder 16 until the stroke amount becomes equal to the upper limit value (1+δ). Become.

Returning to step 225 in FIG. 11, when the detected stroke value is larger than the upper limit (7!+δ) of the predetermined range (if the determination result in step 225 is negative), the attitude control controller 120 moves to step 226. and 227
and outputs an energizing signal to the solenoid 102b of the electromagnetic switching valve 102 and the solenoid of the electromagnetic switching valve 49, respectively, so that the electromagnetic switching valve 102 is switched to the drain position 102C, and the electromagnetic switching valve 49 is also moved to the open position. Operate the switching operation.

Then, the detection value signal of the stroke sensor 16e is monitored (Step 228) until the stroke detection value Lc becomes substantially equal to the upper limit value (l + δ).
26 and 227 are executed repeatedly. When the stroke detection value I5 is substantially equal to the upper limit value (l+δ), the step 225 is executed again, and the stroke detection value I5 is
．． After confirming that the value is less than the upper limit value (1+δ) of the predetermined range, step 230 shown in subsequent FIG. 12 is performed.
Proceed to.

FIG. 23, FIG. 28, and FIG. 29 show the step 22 shown in FIG.
6 and 227;
The electromagnetic switching valve 105 and the electromagnetic switching valve 102 are switched to the switching positions as described above in FIG. 23, and while the pilot oil pressure is maintained at a predetermined constant value, the operating hydraulic pressure path 41 is communicated with the drain tank 91 side. . As a result, pump 1
The hydraulic oil from 00a is no longer discharged to the hydraulic pressure path 41, and conversely, the hydraulic oil is discharged from the hydraulic cylinder 16 to the drain tank 91.

The attitude control controller I/roller 120 supplies an energizing signal to only the electric switching valve ↑49 for the left rear wheel among the electromagnetic switching valves connected to the hydraulic pressure path 41 shown in FIG. The other electromagnetic switching valves 47 and 50 are kept closed. Therefore, as will be described later, the hydraulic oil discharged to the hydraulic pressure path 45 connected to the boat P1 of the hydraulic circuit section 16d of the hydraulic cylinder 16 is transferred to the electromagnetic switching valve 49, the hydraulic pressure path 41, the throttle 103a of the flow control valve 103, It is discharged to the drain tank 9 through the electromagnetic switching valve 102. And hydraulic circuit part] Each bow l-P of Od, 12d, +6d, 18d
P, pilot check valve 5 of flow control valve 55.60
5a and 60a, pilot check valves 54, 59.6
Pilot oil pressure is supplied to each of 4 and 67.

The hydraulic cylinders 10 and 12 on the front wheel side are formed with the hydraulic circuit shown in FIG. 17, and the hydraulic cylinder 18 on the right rear wheel side is formed with the 111 pressure circuit shown in FIG. 18. The operation of each of these hydraulic cylinders is controlled in the same manner as the traveling suspension mode control described above. On the other hand, the hydraulic circuit shown in FIG. 29 is formed in the hydraulic cylinder 16 on the left rear wheel side, and when the electromagnetic switching valve 49 is opened, the hydraulic oil of the hydraulic circuit shown in FIG.
It is discharged into the hydraulic path 45.

The hydraulic oil discharged from the hydraulic circuit of the hydraulic cylinder 16 of the left rear wheel follows the path shown by the arrow in FIG. 29 and a switching valve 30, and is discharged to the hydraulic pressure path 45 via the boat P1. At this time, a part of the hydraulic oil in the accumulator 65 also flows out, lowering the hydraulic pressure, and as a result, the hydraulic pressure in the lower chamber 16f of the screw 1.6b decreases, causing the piston 1.6 b
moves upward (hydraulic cylinder 16 contracts). As the piston 16b moves, a portion of the hydraulic oil is replenished into the piston lower chamber 16g along the same path as the solid arrow in FIG.

As described above, the hydraulic oil discharged into the oil passage 45 is discharged into the drain tank 91 via the opened electromagnetic switching valve 49, the hydraulic pressure passage 41, the throttle 103a of the flow control valve 103, and the electromagnetic switching valve 102. be done.

At this time, the flow rate of the discharged hydraulic oil is controlled by the flow control valve 103.
The hydraulic cylinder 16 is regulated by the orifice 103a.
The hydraulic oil is gradually drained and the hydraulic cylinder 16 of the left rear wheel
gradually contracts in the direction in which the stroke amount decreases, and the hydraulic fluid in the hydraulic cylinder 16 is discharged until the stroke amount -c becomes equal to the upper limit value (β+δ).

Returning to FIG. 12, the attitude control controller 120
Similar to the hydraulic cylinder 16 for the left rear wheel in FIG.
30 and 235).

If the detected stroke value is within the predetermined range l±δ (if both the determination results in steps 230 and 235 are positive), there is no need to adjust the level of the hydraulic cylinder 18; The process proceeds to step 240 shown in FIG. 13 without executing any operation control.

On the other hand, if the stroke detection value LD is smaller than the lower limit value (1-δ) of the predetermined range (and the determination result in step 230 is negative), the attitude control controller 120 executes steps 231 and 232. Solenoid switching valve 102
An energizing signal is output to the solenoid 102a of the solenoid 102a and the solenoid of the electromagnetic switching valve 50 to switch the electromagnetic switching valve 102 to the (J open position) 02A, and also switch the electromagnetic switching valve 50 to the open position (non-operating). And stroke detection value 1
The detection value signal of 86 is monitored (step 233) until the stroke detection value , , is substantially equal to the limit value (1+δ), for the same reason as described above.
1 and 232 are executed repeatedly. When the loaf detection value ri is substantially equal to the upper limit value (ρ+δ), the step 230 is executed again, and the stroke detection value is
After confirming that the value is equal to or greater than the lower limit value (1-δ) of the predetermined range, the process proceeds to the subsequent step 235.

The hydraulic circuit formed by executing steps 231 and 232 can be completed by deenergizing the solenoid of the electromagnetic switching valve 49 in FIG. 26 to close it, and instead energizing and opening the electromagnetic switching valve 50. This circuit is the same as the circuit shown in FIGS. 26, 20, and 27, and since the operation of this circuit can be easily deduced from the above explanation, this explanation will be omitted below.
Due to the hydraulic circuit formed as described above, the hydraulic cylinder 18 on the right rear wheel side expands in the direction in which its stroke amount increases, and the hydraulic cylinder 18 is extended until the stroke amount Ln becomes equal to the upper limit value (7!+δ). Hydraulic oil will be replenished.

Returning to step 235 in FIG. 12, when the detected stroke value is larger than the upper limit (1+δ) of the predetermined range (if the determination result in step 235 is negative), the attitude control controller 120 performs steps 236 and 237. and outputs an energizing signal to the solenoid 102b of the electromagnetic switching valve 102 and the solenoid of the electromagnetic switching valve 50, respectively, so that the electromagnetic switching valve 102 is switched to the drain position 102C, and the electromagnetic switching valve 50 is also moved to the open position. Operate the switching operation. Then, the detection value signal of the stroke sensor 18e is monitored (step 238), and the stroke detection value is determined. step 23 until substantially equal to the upper limit (1+δ).
6 and 237 repeatedly. Stroke detection value L
When D becomes substantially equal to the upper limit value (l + δ), the step 235 is executed again, and it is confirmed that the detected stroke value is equal to or less than the upper limit value (p + δ) of the predetermined range. The process then proceeds to step 240 shown in FIG.

The hydraulic circuit formed by executing steps 236 and 237 can be completed by deenergizing the solenoid of the electromagnetic switching valve 49 in FIG. 28 to close it, and instead energizing and opening the electromagnetic switching valve 50. This circuit is the same as the circuit shown in FIGS. 28, 23, and 29, and since the operation of this circuit can be easily deduced from the above explanation, this explanation will be omitted below.
Due to the hydraulic circuit formed as described above, the hydraulic cylinder 18 on the right rear wheel side gradually contracts in the direction in which its stroke amount decreases, and the stroke amount becomes {circle around (2)}. is the upper limit value (ρ+δ)
The hydraulic oil in the hydraulic cylinder 18 will be discharged until it becomes equal to .

In this way, each hydraulic cylinder 10.12, 16.degree. 18 is always adjusted to its respective reference stroke amount, and the basic posture during traveling is maintained.

When the level adjustment control is completed, the attitude control controller 120 proceeds to step 240 shown in FIG. 13, reads the detected value of the inclination angle θ detected by the inclination angle sensor 122, and
The inclination angle θ in the left-right direction of the vehicle body is set to a predetermined value θN (for example, 10
0) Determine whether or not. If this determination result is affirmative, the attitude control controller 120 performs step 24.
(If step 240 is not executed after step 241 is executed, the operation control of the hydraulic suspension device remains in the traveling suspension mode control described above.) , proceed to Step 2 243.

On the other hand, if the determination result in step 240 is negative, the process proceeds to step 241, and the attitude control controller 120 does not output an energizing signal to any of the solenoids of the electromagnetic switching valves 47, 49, 50, and 102, and switches the electromagnetic switching valves. An energizing signal is output to the solenoid of the valve 105 to form a suspension lock circuit.

Truck crane I has crane 2 on chassis frame 3.
The center of gravity is relatively high because the vehicle is placed on the vehicle, and if the vehicle body leans left or right, the center of gravity shifts and becomes unstable. When the vehicle body tilts, the proportion of the load applied to the wheels on the tilting side increases, and the amount of sinking of the vehicle body on the tilting side increases. When the angle of inclination θ becomes larger than the predetermined value θ8, the rotation angle control restricts (zero) the expansion and contraction of each hydraulic cylinder 10.12° 16, 18 to prevent an increase in the sinking amount, and prevents the rotation angle (left-right stability ).

30 to 32 show the hydraulic circuit formed by executing step 241, in which the solenoids 102a and 102b of the electromagnetic switching valve 102 are both deenergized and the electromagnetic switching valve 102 is switched to the neutral position 102B. Ori,
The hydraulic oil from the hydraulic pump 100a is not discharged and supplied to the hydraulic pressure path 41, but is returned to the drain tank 91. Also, since the solenoid 105a of the electromagnetic switching valve 105 is energized, it is switched to the switching position where the boats 105b and 105e and the boats 105c and 105d of the electromagnetic switching valve 105 are connected, respectively, and the oil passage is connected from the hydraulic pump 100b. The pilot pressure oil discharged to 51a is returned to drain tank 91. Therefore, pilot check valve 2B, 54, 59
, 64.6T, etc., and the pilot operated switching valve 27, etc. are all closed. Furthermore, the attitude control controller 1
Reference numeral 20 outputs an energizing signal to each of the electromagnetic switching valves 47, 49, and 50, and these electromagnetic switching valves are in a closed state. As a result, the piston upper chamber] Of (12f, 16f.

I8'') and piston lower chamber 10g (12g, J
6g.

18g) is trapped in these piston chambers and in the lower piston chamber, and the pistons 10b, 1
2b, 16b, +8b cannot move and the hydraulic cylinders 10, 12, 16.18 are locked.

The attitude control controller 120 is a hydraulic cylinder 10°12
, 16 and 18 in the locked state, monitor the detection signal from the inclination angle sensor 122, and repeat steps 240 and 241 until the inclination angle θ becomes equal to or less than the predetermined angle θ, and the hydraulic cylinder 10° 12.16.18 held locked. Further, the predetermined angle θ has an inclination angle θ larger than the predetermined angle θ8.

(for example, 206) or more, the attitude control controller 120 sounds an alarm buzzer (not shown) to notify the danger. Further, when the engine 110 is stopped and the power supply to the attitude control controller 120 is stopped,
Although it becomes impossible to supply the energizing signal to the electromagnetic switching valve 105,
Hydraulic pump] 00a.

100b also stopped and the operating oil pressure and pyro throat oil pressure decreased.
In this case, the pilot check valves 28, 54, 59, 64, 67, etc. and the pilot operation switching valve 27, etc. are all kept closed because the predetermined pilot oil pressure is not supplied. The hydraulic cylinders 10, 12, 16, 18 are maintained in a locked state.

When the inclination angle θ becomes less than the predetermined angle 08, the suspension lock circuit is released as described above (step 24).
2) Go to step 243 for i&'4.

In step 243 of FIG. 13, the attitude control controller 120 determines whether the brake pressure switch 125 is off, that is, if the brake pedal 26 is not depressed and the brake in the brake tube 128 is not pressed. It is determined whether the working oil pressure is below a predetermined pressure.

If this determination result is affirmative, the process proceeds to step 250 in FIG. 14, which will be described later. If negative, that is, if the brake pedal 126 is depressed and the brake operating oil pressure in the brake tube 128 is higher than a predetermined pressure, the process proceeds to step 244. The advancing attitude control controller +20 outputs an energizing signal to the solenoids 02a and 05a of the electromagnetic switching valves 102 and 105, and the solenoids of the electromagnetic switching valves 47, 49, and 50 are deenergized and the electromagnetic switching valves 47. 49.50 is closed to form an anti-nose dive circuit.

When the brake pedal 126 is pressed to apply sudden braking while the vehicle is running, the crane 2 is placed on top of the vehicle, and the front of the vehicle, which has a center of gravity at a relatively high position, sinks due to inertia, while the rear of the vehicle floats. Therefore, the forward downward angle tends to increase, but the purpose of anti-nose dive control is to suppress the downward downward angle from increasing during braking.

33 to 35 show hydraulic circuits formed by the execution of steps 244,
As a result, the solenoid 102a of the electromagnetic switching valve r102 is energized, and as a result, the electromagnetic switching valve 102 is switched to the open position 102A, and a constant hydraulic pressure is supplied to the hydraulic pressure path 41. This hydraulic oil is supplied to the flow control valve 103, check valve 71 (
(See Figure 3) is supplied to the pilot oil line 52 to generate pilot oil pressure, and this pilot oil pressure is applied to the pilot oil pressure valves 54, 59, 64, and 67.
(This will cause these pilot check valves to open.

On the other hand, when the solenoid 105a of the electromagnetic switching valve 105 is energized, the bows 1-105b and 10 of the electromagnetic switching valve 105 are energized.
The pilot pressure oil discharged from the hydraulic pump 100b to the oil path 51a is returned to the drain tank 91. Therefore, the pilot check valve 28
, 29.55a.

60a1 and pilot operated switching valve 27.30 are both closed. Furthermore, the attitude control controller 120
does not output an energizing signal to any of the electromagnetic switching valves 47, 49, and 50, and these electromagnetic switching valves are in a closed state. As a result, the hydraulic circuit shown in FIGS. 34 and 35 is formed.

When the hydraulic cylinder 10 (12) on the front wheel side contracts during braking and the piston 10b (12b) is displaced upward, hydraulic oil is discharged from the piston upper chamber 10f (12f) as shown by the arrow in FIG. Some of the oil is in the viroft check valve 54 (59), which is in an open state, and the oil passage 74 (76).
), pilot check valve 29 of oil passage 23, oil passage 22
The piston lower chamber Lo
g (12g), and the remainder flows into the flow control valve 55 (60).
Flows into the accumulator 57 (62) via. At this time, since pilot hydraulic pressure is not supplied to the pilot check valve 55a (60a) of the flow control valve 55 (60), the flow toward the accumulator 57 (62) via this pilot check valve 55a (60a) is blocked. and only flow through the throttle 55b (60b) is allowed. Moreover, the above-mentioned pilot check valves 28 and 29
As described above, since these are pilot-operated check valves with throttles, the flow rate of the hydraulic oil flowing through these check valves 28 and 29 is regulated. Therefore, the force acting on the hydraulic cylinders 10 and 12 on the front wheel side due to the nose dive during sudden braking and trying to contract them is transferred to the throttle 55b (60b) of the flow control valve 55 (, 60) and the pilot check valve. It is attenuated by the aperture effect of 28.29.

Note that when the hydraulic circuit for anti-nose dive control during braking is formed, even if the hydraulic cylinder 10 (12) attempts to extend, the pilot check valve 28 and the pilot operation switching valve 27 are not supplied with pilot hydraulic pressure, so they are closed. In this state, the flow of hydraulic oil from the lower piston chamber 10g (12g) to the upper piston chamber 10f (12f) is blocked, and the piston 10b (12b) cannot be displaced downward, that is, the hydraulic cylinder 10 ( 12) cannot be expanded.

On the other hand, even if the hydraulic cylinder 16 (18) on the rear wheel side tries to extend during sudden braking, pilot hydraulic pressure is not supplied to the pilot check valve 28 and the pilot operation switching valve 27 shown in FIG. 35, so they cannot be closed. The check valve 28 and the switching valve 27 prevent the hydraulic fluid from flowing out from the piston lower chamber 10g, and the hydraulic cylinder 16 (18) cannot extend. However, when the rear wheel side hydraulic cylinder 16 (1B) tries to contract, the piston 16b (18b) is displaced upward, and at this time, the piston upper chamber 16f (
Hydraulic oil is discharged from 18f), and a portion of this hydraulic oil flows through the pilot check valve 64 (67), the oil passage 78 (80), and the pilot check valve 29 of the oil passage 23, which are in the open state as shown in FIG. , flows into the piston lower chamber 16g (18g) via the pilot check valve 28 of the oil passage 22, and the remainder flows into the accumulator 65 (68). At this time, similarly to the hydraulic circuit on the front wheel side shown in FIG. 34, the throttle action of the pilot check valves 28 and 29 causes the piston upper chamber 16f (18f) to move from the piston lower chamber 16g (18g).
The hydraulic oil directed to the hydraulic cylinder 16 (1B) is regulated.
The force that acts on them and tries to extend them is attenuated.

In this way, during sudden braking, the front wheel side hydraulic cylinder 10°12
is check valve with throttle 55b, 60b and throttle 28.29
As a result, the hydraulic cylinder 16 (1B) on the rear wheel side is only allowed to move in the direction of contraction.
This avoids a phenomenon in which the front part of the vehicle has an excessive downward angle (nose dive).

After the attitude control controller 120 forms the above-mentioned hydraulic circuit for anti-nose dive control, it again determines whether the brake pressure switch 125 is turned off or not (step 24).
5) If the brake pressure switch 125 is not turned off, steps 244 and 245 are repeatedly executed to keep the anti-nose dive control hydraulic circuit formed.

On the other hand, when the brake pedal 126 is released and the brake pressure switch 125 is turned off, and the determination result in step 245 is affirmative, the attitude control controller 120 sets the built-in tO timer (which may be a program timer, etc.) at step 246. ), the timer determines whether a predetermined time to (for example, 3 to 4 seconds) has elapsed (step 247). Then, wait for the elapse of a predetermined time to, and when the predetermined time to has elapsed, step 244
At step 248), the hydraulic circuit formed in step 248 is released and returned to the hydraulic circuit shown in FIGS. 16 to 18, and the process proceeds to step 250 in FIG. 14. In this way, even if the brake pressure switch 125 is turned off, the anti-nose dive circuit is not released immediately, but only after the predetermined time to has elapsed, thereby reliably preventing nose dive and improving ride comfort. It can be improved.

In step 250, the attitude control controller 120 receives a predetermined signal from the lower acceleration (G) sensor 124 indicating that the upward acceleration G of the vehicle body exceeds a predetermined value, or It is determined whether a signal (off signal) that is not one of the predetermined signals indicating that the acceleration G exceeds a predetermined value is output. This determination determines whether or not the vehicle is pitching due to driving on rough terrain, etc. If the determination result is affirmative, the attitude control controller 120 does not execute the pitching prevention control and performs the current control program. Terminate execution of the loop.

On the other hand, if the determination result in step 250 is negative, that is, a predetermined signal is sent from the vertical acceleration (G) sensor 124 indicating that the upward acceleration G of the vehicle body exceeds a predetermined value, or the downward acceleration G exceeds a predetermined value. If any of the predetermined signals indicating that the
A hydraulic circuit for preventing pitching is formed in response to a signal from 24.

This pitching prevention control hydraulic circuit is for suppressing and eliminating pitching vibrations of the vehicle caused, for example, by running on rough terrain. The acceleration in the upward direction (direction of floating) is a predetermined value (for example, 0.2
G, but for vibration! If a signal indicating that the IJI (IJI 211z or less) has been exceeded is detected, the hydraulic circuit shown in FIGS. 16 to 18 described above is formed. This hydraulic circuit is connected to the weight hydraulic cylinder 10 (12, 16,
18) When extended, the piston lower chamber 10g (12g, 1
6g, 18g) to the piston upper chamber 10f (12f,
16f, 18f) through the pilot check valve 28 with throttle and the throttle 2 of the flow control valve 26.
This is controlled by the throttling action of 6a, and this throttling action can attenuate the impact on the vehicle body in two directions.

When the hydraulic cylinder 16.18 on the rear wheel side contracts, the piston upper chamber 16f, 18f is transferred to the piston lower chamber 1.
The flow rate of the hydraulic oil toward 6g and 18g is regulated by the throttle pilot check valve 28, and the throttle action of the throttle 26a and check valve with throttle 26b of the flow rate control valve 26.
This throttling action damps the retracting movement of the hydraulic cylinders 16,18.

On the other hand, the attitude control controller 120
) When a predetermined signal from the sensor 124 is detected indicating that the acceleration of the vehicle body in the downward direction (sinking direction) exceeds a predetermined value (for example, 0.2 G, but below JUL 2 Hz for vibration) 33 to 35 explained earlier.
Form the hydraulic circuit shown in the figure. As mentioned above, this hydraulic circuit allows only the contraction of the hydraulic cylinder] 0 (+2.16.18) and restricts its extension.Moreover, when the hydraulic cylinder]0 (+2.16.18) contracts, the piston From the upper chamber 10f (12f, 16f, 18f) to the piston lower chamber 10g (12g.

16g, 18g) with a pilot check valve 28.29 and a flow control valve 55°60
The throttle action of each of the throttles 55b and 60b is used to restrict the impact, and this throttling action can attenuate the downward impact of the vehicle body. In addition, the hydraulic cylinder 1 on the rear wheel side
If 6 and +8 are extended, the hydraulic cylinder 16.1
8 are in the locked state and these hydraulic cylinders 16.1
8 is regulated.

In this manner, the vehicle is controlled by alternately switching between the hydraulic circuits shown in FIGS. 16 to 18 and the hydraulic circuits shown in FIGS. 33 to 35 in accordance with the signal from the vertical acceleration (G) sensor 124. Pitching can be rapidly attenuated and eliminated.

Next, the attitude control controller 120 performs the next step 25.
After setting a t1 timer that measures the elapse of a predetermined time t1 in step 2, it is determined whether the signal from the vertical acceleration (G) sensor 124 has been inverted to the off signal (step 253). If this determination result is positive, step 2
55, the pitching prevention control hydraulic circuit is released and returned to the hydraulic circuit shown in FIGS. 16 to 18, and the execution of the current loop of the control program is completed.

If the determination result in step 253 is negative, that is, if the signal from the vertical acceleration (G) sensor 124 is not the off signal, the process advances to step 254, and step 2
In step 52, it is determined whether the predetermined time t1 has elapsed since the timer was set, and if it has not elapsed yet, steps 253 and 254 are repeatedly executed.

That is, the pitching prevention circuit continues to be maintained to attenuate pitching. If the determination result in step 254 is affirmative, the process proceeds to step 255 and the pitching prevention circuit is released. That is, in this case, the vertical acceleration (G) sensor 124 detects that the vehicle body is still in a pitching state, but since the hydraulic circuit for preventing this pitching state has been formed for a long time, the pitching state is not detected. This is to temporarily release the anti-visoting circuit even if the device has not yet escaped. This is to give priority to operation controls such as level adjustment control and angle turning control, which have higher priority than pitching prevention control, and by canceling the pitching prevention circuit, these higher priority operation controls can be prioritized. It can be executed by If there is no need to execute high-priority operation control such as level adjustment control or angle turning control, the process returns directly to step 251;
The pitching prevention circuit is re-formed, and since the time required to execute the program during this time is short, there is virtually no inconvenience.

Returning to step 200 in FIG. 9 above, if the determination result is negative in this step, that is, if the manual changeover switch 134 is in the manual mode position and outputting an on signal, the Proceed to step 260 in FIG. As described above, the manual changeover switch 134 is activated when the transmission (not shown) of the truck crane 1 is switched to any one of the neutral, very low gear, and - gear positions, and the manual changeover switch 134 is switched to the manual mode position. It outputs an on signal to the manual changeover switch 134.
When step 260 is executed in response to the ON signal, the posture control controller 120 forms a suspension lock circuit.

This suspension lock circuit is the same as the circuit shown in FIGS. 30 to 32 formed by the angle rotation control,
If this suspension lock circuit is formed when suspension work is performed with the vehicle stopped, or when suspension work is performed while the vehicle is running below a predetermined speed, each hydraulic cylinder 10, 12, 16° 18 becomes unable to expand or contract ( Therefore, the suspension function of the hydraulic suspension device is lost, and the crane 2 is suspended in a so-called on-tire condition, thereby stabilizing the suspension operation.

Next, in step 261, the attitude control controller 120 determines whether the vertical control switch 132 is in the neutral position and is not outputting any command signal (off). As described above, this vertical control switch 132 generates a command signal to move the vehicle body up and down according to the tilting angle when the lever 132a is tilted in the longitudinal direction of the vehicle body.If the determination result in step 261 is negative, i.e. If the manual changeover switch 134 is outputting an on signal and the lever 132a is tilted in either the longitudinal direction, the process proceeds to step 262, and the attitude control controller 120 forms a vehicle height up/down circuit. .

This vehicle height control is useful when you want to change the suspension height by slightly adjusting the vehicle height without changing the suspension position by the crane 2 during suspension work, for example, when you want to change the suspension height when traveling on rough terrain. This is effective when you want to move i1!1 jJ across an obstacle by increasing the height of the vehicle, and when raising the vehicle body by tilting the lever 132a backward, the steps shown in FIGS. 20, 22, 27, and 36 are useful.
The hydraulic circuit shown in the figure is formed.

That is, the attitude control controller 120 is the electromagnetic switching valve 105
The electromagnetic switching valve 105 is opened without outputting an energizing signal, and a constant pressure pilot oil pressure is generated in the pilot oil passage 51, and an energizing signal is output to the solenoid 102a of the electromagnetic switching valve 102 to set it to the open position. Switch to 102A,
Ear hydraulic oil at a predetermined pressure is generated in the hydraulic pressure path 41. Then, the pilot hydraulic pressure generated in the pilot oil passage 51 is supplied to the pilot pressure control valves 28, 29, 55a, 60a and the pilot switching valves 21.30 to open these check valves and switching valves, and the pilot oil pressure is supplied from the hydraulic pressure passage 4I. The biloft hydraulic pressure generated in the pilot oil passage 52 via the check valve 71 is applied to the pilot check valves 54, 59, 64. and 67 to open these check valves.

Additionally, the attitude control controller 120 includes an electromagnetic switching valve 47.4.
9. Each solenoid 1 of 50 is energized and opened,
The hydraulic oil in the hydraulic pressure path 41 is supplied to the hydraulic circuit section through these opened electromagnetic switching valves 47, 49, and 50.]Od (12
d, 16d, 18d) are supplied to each boat P1. Then, as can be easily inferred from the explanation of the level adjustment control described above, the hydraulic oil supplied to the boat P1 is
The hydraulic circuit shown in FIGS.
, 18b simultaneously push down the hydraulic cylinder +
Extend 0.12°16.18 by the same stroke amount. As a result, the vehicle body moves in the L direction while maintaining a horizontal state. At this time, attitude control controller 1
20 is each stroke detection value 10 e (12e, 16
e.

While monitoring the stroke detection values from 18e), these stroke detection values are applied to the vertical control switch 132.
The hydraulic circuits shown in FIGS. 20, 22, 27, and 36 are maintained until the value corresponding to the angle of inclination of lever 132a is reached, and the height is reached to the desired height corresponding to the angle of inclination of lever 132a. Raise the vehicle.

When the vehicle body is lowered by tilting the lever 132a forward, the hydraulic circuits shown in FIGS. 23, 25, 29, and 37 are formed.

That is, the attitude control controller 120 is the electromagnetic switching valve 105
The electromagnetic switching valve 105 is opened without outputting an energizing signal, and a constant pressure pilot oil pressure is generated in the pilot oil passage 5I, and an energizing signal is output to the solenoid 102b of the electromagnetic switching valve 102 to set the drain position. 102C to connect the hydraulic pressure path 41 to the drain tank 91 side. Then, the pilot oil pressure generated in the pilot oil passage 51 is transferred to the pilot check valves 28, 29.55a, 60a.
and the pilot switching valves 27 and 30 to open these check valves and switching valves, and the pilot oil passage 51
The pilot hydraulic pressure generated in the pilot oil passage 52 via the check valve 70 is controlled by the pilot check valve 54.5.
9.64. and 67 to open these check valves.

The hydraulic cylinder 10.12 on the front wheel side has a hydraulic circuit shown in FIG. 25, and the hydraulic cylinder 16.18 on the rear wheel side has a hydraulic circuit 29
The hydraulic circuits shown in the figure are formed, and when the attitude control controller 120 energizes and opens the solenoids of the electromagnetic switching valves 47, 49, and 50, the hydraulic circuit parts 10d (12d,
16d, 18d) The hydraulic oil in the hydraulic pressure paths 43 to 46 connected to each boat P1 is supplied to each electromagnetic switching valve 47, 49. 5
0, hydraulic pressure path 41, throttle l03 of flow control valve 103
a. It is discharged to the drain tank 91 via the electromagnetic switching valve 102. From the explanation of the level adjustment control mentioned above, each hydraulic cylinder 10.12
．． Hydraulic oil flows from the hydraulic circuit of 16°18 in Figures 25 and 2.
Each hydraulic pressure path 43 to 46 is connected via the path indicated by the arrow in Fig. 9.
The hydraulic pressure in each hydraulic circuit decreases, and each hydraulic cylinder 10, 12, 16, 18 simultaneously contracts by the same stroke amount, and the vehicle body moves downward while maintaining a horizontal state. At this time, the attitude control controller 120 controls each stroke sensor 1 as in the case of raising the vehicle height described above.
0e (12e, 16e.

While monitoring the stroke detection values from 18e), these stroke detection values are applied to the vertical control switch 132.
The hydraulic circuits shown in FIGS. 23, 25, 29, and 37 are held until the value corresponding to the angle of inclination of the lever 132a is reached, and the vehicle body is raised to a desired height according to the angle of inclination of the lever 132a. lower it. When the vehicle body descends to a height corresponding to the inclination angle of the lever 132a, the attitude control controller 120 forms a suspension lock circuit to lock the hydraulic cylinders 10, 12, 16. It is determined whether the control switch 132 is off.

(Left space below this page) When the vehicle body is at the desired height, press the vertical control switch 1.
If the lever 132a of 32 is in the neutral position and the determination result in step 261 is affirmative, the process advances to step 264, and the posture control switch 130 is in the neutral position and is not outputting any command signal (is it off?). Determine whether or not. As described above, this posture control switch 130 generates a command signal to tilt the vehicle body according to the tilting direction and tilting angle when the lever 130a is tilted forward, backward, left, or right.If the determination result in step 264 is negative, , that is, the manual changeover switch 134
is outputting an on signal and the lever 130a is tilted in either the front, back, left, or right direction, the process proceeds to step 265, and the attitude control controller 120 forms an attitude control circuit.

This posture control is effective for maintaining the vehicle body in a horizontal posture and stabilizing the suspension work during suspension work on a slope, etc., and is shown in the table below depending on the direction and angle of the lever 130a's inclination. A hydraulic circuit is formed. In addition, lever 130
The inclination angle of a is +α to -α in the front-back direction, and +β in the left-right direction.
It is defined as ~-β.

(Left below) In the above table, for example, if the lever 130a is tilted forward by an angle corresponding to an angle α (0<α≦α,) that is less than or equal to a predetermined angle α, the oil pressure as shown in Fig. 23.24.25. A circuit is formed and the hydraulic cylinder 10.12 on the front wheel side is contracted, and the front wheel is moved forward at a predetermined angle α, or more, and at a predetermined angle α8.
When tilting by an angle corresponding to the following angle α (α8<α≦αN), the hydraulic circuit shown in Fig. 23.24.25 is first formed and the hydraulic cylinder 10.12 on the front wheel side is contracted. By forming a circuit similar to that shown in Figures 20, 26, and 27, the hydraulic cylinders 16 and 18 on the rear wheel side are extended, and the front part of the vehicle body is sunk by a desired angle. still,
It is not allowed to tilt the vehicle body by more than the predetermined angle α8 because it destroys the stability of the vehicle body.

The posture control controller 120 controls each stroke sensor 10.
While monitoring the stroke detection values from e (12e, 16e, 18e), the inclination angle calculated from these stroke detection values reaches a value corresponding to the tilting angle of the lever 130a of the posture control switch 130 as shown in the table above. The hydraulic circuit is held and the vehicle body is tilted to a desired tilt angle according to the tilting angle of the lever 130a.

-1- When simultaneously contracting the hydraulic cylinders 10.12 on the front wheel side according to the table, the attitude control controller 120 forms the hydraulic circuit shown in FIG. 23.24.25. This hydraulic circuit is connected to steps 216 and 217 in FIG.
Since it is the same as the circuit formed in , a detailed explanation will be omitted.

When simultaneously extending the hydraulic cylinders 10.12 on the front wheel side, the attitude control controller 120
The hydraulic circuit shown in Figure 2 is formed.

This hydraulic circuit is connected to steps 211 and 21 in FIG.
Since it is the same as the circuit formed in step 2, detailed explanation thereof will be omitted.

When simultaneously contracting the rear wheel side hydraulic cylinders 16.18, the attitude control controller 120
A circuit similar to the circuit shown in FIG. 9 is formed. That is, the attitude control controller 120 is configured to control the electromagnetic switching valve 4 shown in FIG.
When the energizing signal is output to the solenoid of No. 9, the energizing signal is also output to the solenoid of the electromagnetic switching valve 50 in Jt to open these electromagnetic switching valves 49 and 50.
The same circuit as that shown in FIG. 29 is formed.

Then, the hydraulic oil in the hydraulic cylinders 16 and 18 is simultaneously discharged to the drain tank 91 side, and the hydraulic cylinders 16 and 18 both contract, causing the rear part of the vehicle body to sink. The detailed operation of this hydraulic circuit can be easily deduced from the description of the circuit shown in FIGS. 23, 28, and 29, so the explanation will be omitted below.

When simultaneously extending the hydraulic cylinders 16.18 on the rear wheel side, the attitude control controller 120
A circuit similar to the circuit shown in FIG. 7 is formed. That is, in this case as well, the attitude control controller 120 outputs an energizing signal to the solenoid of the electromagnetic switching valve 49 shown in FIG. The switching valves 49 and 50 are opened, and the other circuits are the same as the circuit shown in Fig. 20.26.27. Then, the hydraulic oil is simultaneously replenished into the hydraulic cylinders 16 and 18, and the hydraulic cylinders 16 and 18 are extended together, causing the rear part of the vehicle body to rise.

The detailed operation of this hydraulic circuit can be easily deduced from the description of the circuit shown in FIGS. 20, 26, and 27, so the explanation will be omitted below.

When simultaneously retracting the left hydraulic cylinder 10.16, the attitude control controller 120 moves to the 23.25°29
．． A hydraulic circuit shown in FIG. 38 is formed. In this case, the attitude control controller 120 opens the electromagnetic switching valves 47 and 49 of the electromagnetic switching valves 47, 49, and 50. Then, the hydraulic oil is discharged from the hydraulic cylinder 16 on the left rear wheel side to the drain tank 91 in the same manner as described in FIG. 29 of J, and the left rear wheel sinks. In addition, since the electromagnetic switching valve 47 is also opened, the hydraulic oil is about to be discharged from the hydraulic cylinders 10 and 12 on the front wheel side, but the hydraulic circuit 18 on the right rear wheel does not expand or contract, and the hydraulic cylinder on the left rear wheel Since only the wheel 16 sinks, the chassis frame 3 is twisted in the direction in which the left wheel side sinks. At this time, since the chassis frame 3 has high rigidity, a force is applied to the left hydraulic cylinder 10 on the front wheel side to contract it, and a force is applied to the right hydraulic cylinder 12 to extend it to -υ. Left hydraulic cylinder 10
Only the hydraulic oil is discharged through the path shown in FIG.
2 is Ichimaro in its original position without expanding or contracting.

In this way, the front and rear left wheels 4.8 sink at the same time, and the vehicle body tilts with its left side down.

When simultaneously contracting the right hydraulic cylinders 12.18, the posture control controller 120
．． In the hydraulic circuit shown in Fig. 38, the electromagnetic switching valve 50 is used instead of the electromagnetic switching valve 49 ((I), and when the electromagnetic switching valve 49 is closed and the electromagnetic switching valve 50 is opened, the hydraulic pressure on the right rear wheel side is Hydraulic oil is discharged from the cylinder 18 to the train tank 91, and the right rear wheel sinks.As the right rear wheel sinks, the hydraulic cylinder 12 of the right front wheel contracts, causing the front and rear right wheels to sink. 4 and 8 sink at the same time, causing the vehicle to tilt with its right side down.

When the left hydraulic cylinder 10.16 is extended at the same time, the attitude control controller 120 moves to the 20.22°2 position.
7.39 Form the hydraulic circuit shown in Figure. In this case, the attitude control controller 120 has a solenoid switching valve of 47°49.50°.
Of these, the electromagnetic switching valves 47 and 49 are opened. Then,
The hydraulic cylinder 16 is replenished with hydraulic oil, and the hydraulic cylinder 1
6 extends and the left rear wheel lifts. In addition, the electromagnetic switching valve 4
Since hydraulic cylinders 10 and 12 on the front wheel side are also opened, hydraulic oil is about to be replenished, but the hydraulic circuit 18 on the right rear wheel does not expand or contract, and only the hydraulic cylinder 16 on the left rear wheel expands. Therefore, the chassis frame 3 is twisted and rotted in the direction in which the left wheel side lifts up. Since the chassis frame 3 has high rigidity, a force is applied to the left hydraulic cylinder 10 on the front wheel side to extend it, and a force is applied to the right hydraulic cylinder 12 to contract it. Hydraulic oil is replenished only into cylinder 10 through the path shown in FIG. 22, causing hydraulic cylinder 10 to extend, and right hydraulic cylinder 12 to remain at its original position without expanding or contracting.

In this way, the front and rear left wheels 4.8 lift up at the same time, and the vehicle body tilts with its right side down.

When simultaneously extending the right hydraulic cylinders 12.18, the attitude control controller 120 moves to the 20°22.27° position.
．． In the hydraulic circuit shown in Fig. 39, the electromagnetic switching valve 50 is energized instead of the electromagnetic switching valve 49, and the electromagnetic switching valve 49 is closed and the electromagnetic switching valve 50 is opened. Hydraulic oil is replenished into the cylinder 18, and the right rear wheel is lifted off the ground. Then, as the right rear wheel lifts up, the hydraulic cylinder 12 of the right front wheel expands, and the front and rear right wheels 4.8 lift up at the same time, causing the vehicle body to tilt with its left side down.

When the vehicle body is tilted to an angle corresponding to the inclination angle of the lever 130a of the posture control switch 130, the posture control controller 120 forms the suspension rotor circuit to lock the hydraulic cylinders 16 and 18 by +0.12 degrees, and then restarts the vehicle body. Returning to step 261, the determination step is executed. If the determination results in steps 261 and 264 are both affirmative, the execution of the current loop of the attitude control program is ended.

(Effects of the Invention) As detailed above, according to the method for avoiding nose dive during vehicle braking of the present invention, between the chassis frame and the axle,
A hydraulic cylinder having a piston side chamber defined by a piston and a piston other side chamber on the piston rond side is interposed, the piston one side chamber and the piston other side chamber are communicated by an oil passage, and in the middle of the oil passage, an accumulator that has a gas chamber and an oil chamber defined by a movable partition wall, and stores in the oil chamber a part of the hydraulic oil discharged from the chamber on one side of the piston when the piston moves; A throttle valve means having at least first and second switching positions for regulating the flow rate of the flowing hydraulic oil is disposed, and a braking state of the vehicle is detected, and the throttle valve means is configured to control the throttle valve means when the vehicle is in a non-braking state. At one time, the switching position is switched to a first switching position in which a predetermined damping force is obtained in response to each contraction and extension of the hydraulic cylinder, and when the vehicle is in a predetermined braking state, the damping force is switched to a first switching position in response to the extension of the hydraulic cylinder. When this is prohibited and the switch is switched to a second switching position that provides a damping force greater than the first switching position against contraction, and when it is detected that the vehicle has changed from the predetermined braking state to the non-braking state. Since the second switching position is switched to the first switching position after a predetermined time has elapsed from the time of detection, the spring function and shock absorbing function are realized when the vehicle is running, and road surface irregularities etc. are realized. This has the effect of alleviating the shock and vibration caused by the brakes, and reliably avoiding excessive nose dive during sudden braking, thereby improving riding comfort.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show one embodiment of the present invention, in which FIG. 1 is a side view of a truck crane on which the hydraulic suspension device according to the present invention is mounted, and FIG. 2 is a side view of the truck crane shown in FIG. 1. FIG. 3 is a hydraulic circuit diagram of the hydraulic suspension device according to the present invention, and FIG. 4 is a hydraulic circuit section 10d of the hydraulic cylinder shown in FIG. 12d, 16d, and 18d, FIG. 5 is a hydraulic circuit diagram of the supply system for hydraulic oil and pilot oil pressure, and FIG. 6 is the input/output of the attitude control controller that controls the operation of the hydraulic suspension device according to the present invention. 7 is a cross-sectional configuration diagram showing details of the check valve 26b constituting the flow control valve 26 in FIG. 4, and FIG. 8 is a cross-sectional configuration diagram showing details of the pilot check valve 28 in FIG. 4. 9 to 15 are program flowcharts 1, illustrating the operation control procedure of the hydraulic cylinder executed by the posture control controller 120 of FIG. 6, and FIGS. Fig. 19 is a hydraulic circuit state diagram for explaining the operation, and Figs. 20 to 39 are graphs showing the relationship between piston speed and damping force for explaining the shock absorber function of the hydraulic suspension device according to the present invention. Each figure is a hydraulic circuit state diagram for explaining the operation of the hydraulic suspension device according to the present invention. 1... Truck crane, 3... Chassis frame,
4...Front wheel, 5...Front axle, 8...Rear wheel, 9...Rear axle, 10. ], 2, 1.6.1
8...Hydraulic cylinder, ]Ob, ], 2b, '16b,
18b...Piston, 10e, 12e, 16e, 18
e・-Stroke sensor, 10f, 12f, L6f, 1
8f...Piston" 2 units, 10g, 12g, 16g,
18g...Piston lower chamber, 21, 22.23...Oil passage, 25...Relief valve, 26...Flow rate control valve, 2
6a... Throttle, 26b... Check valve with throttle, 26
0...Poppet, 265...Spacer, 27...
Pilot switching valve, 28゜29... Pilot check valve, 280... Poppet, 283... Screw 1-ne, 283a... Screw [front, 289... Spacer, 30... Pilot switching valve , 41... Operating hydraulic path, 47, 49.50... Solenoid switching valve, 51° 52.
... Pilot oil path, 54.59.64.67 ... Pilot check valve, 55.60 ... Flow rate control valve, 5
5a, 60a... pilot check valve, 55b,
60 b... Throttle, 57°62, 65.68... Accumulator, 70.71... Check valve, 73~8
0-...oil path, 91-=drain, 100a, 100
b...Hydraulic pump, 102...Solenoid switching valve, 103
...Flow control valve, 105...Solenoid switching valve, 120.
...Attitude control controller, 122...Tilt angle sensor, 124...Two lower acceleration G sensors, 125...Brake pressure switch, 130...Attitude control switch, 132...Vertical control switch, 134
...Manual changeover switch. Applicant: Mitsubishi Motors Corporation Agent: Patent Attorney: Kan Nagato
Figure 9 Figure 20

Claims (1)

[Claims] A hydraulic cylinder having a chamber on one side of the piston defined by a piston and a chamber on the other side of the piston on the piston rod side is interposed between the chassis frame and the axle, and the one side chamber of the piston and the other side chamber of the piston are communicated through an oil passage. and a gas chamber and an oil chamber defined by a movable partition wall are provided in the middle of the oil passage, and a part of the hydraulic oil discharged from one side chamber of the piston due to movement of the piston is stored in the oil chamber. An accumulator and a throttle valve means having at least first and second switching positions for regulating the flow rate of the hydraulic oil flowing in the oil passage are provided, and the brake state of the vehicle is detected and the throttle valve means is adjusted. When the vehicle is in a non-braking state, the switching position is switched to a first switching position in which a predetermined damping force is obtained in response to contraction and extension of the hydraulic cylinder, respectively, and when the vehicle is in a predetermined braking state, The extension of the hydraulic cylinder is prohibited, and the contraction is switched to a second switching position in which a damping force greater than that in the first switching position is obtained, and the vehicle changes from the predetermined braking state to the non-braking state. A method for avoiding nose dive when braking a vehicle, characterized in that when a change in the switching position is detected, the switching position is switched from the second switching position to the first switching position after a predetermined time has elapsed from the time of detection.