JPH0445371B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle having a displacement suppressing mechanism, and particularly to a vehicle having a chassis vibration suppressing mechanism that moves vertically and rotates depending on road surface conditions or rapid acceleration or deceleration of the vehicle.

Conventional mobile cranes and the like have large heavy parts such as a chassis with ground running tires and a crane boom that is rotatable and extendable on the chassis. Low-pressure tires with high elasticity and compressibility are used as tires, and elastic support springs are provided between the axle and the chassis. These tires and springs constitute a support mechanism that supports the chassis so that it can move up and down relative to the road surface. When moving due to a change of work site, the crane boom is lowered to the transfer position and fixed to the chassis. When a vehicle is moved over a rough road surface and rapidly accelerates or decelerates, the heavy chassis and heavy boom move up and down and rotate relative to the road surface. These displacements, which are caused by the elastic support of the tires and support springs, are undesirable.
In other words, it becomes difficult for the driver to drive, and in some cases, the vehicle may temporarily leave the road surface. Furthermore, undesirable vertical and torsional dynamic loads are applied to the axle and other parts. As a result, the road surface may be damaged.

US Pat. No. 2,744,749 is known as a solution to such problems. Another known example is US Pat. No. 3,322,379.
However, it is still insufficient to solve the above-mentioned problems.

In the present invention, a vehicle such as a mobile crane, which has a chassis supported by low-pressure tires, an axle support spring, and a heavy object such as a telescopic crane boom supported by these, rotates and moves up and down. A mechanism is provided to suppress displacement. Since the chassis is elastically supported, it rotates or moves up and down relative to the road surface depending on the condition of the road surface or when the vehicle accelerates or decelerates. In addition, heavy objects also move up and down and rotate relative to the chassis.

For example, if the heavy object is a telescoping crane boom, it is connected to the chassis by a pivot mechanism and reciprocated around a horizontal axis relative to the chassis by a hydraulic boom hoist cylinder or the like that moves the boom up and down. It is considered possible to move.

The displacement suppressing mechanism or stabilizing mechanism of the present invention includes an elastic mechanism such as an auxiliary spring connected between the chassis and the crane boom, and a dump mechanism that controls the compression and restoring speed of the auxiliary spring to suppress rotational displacement of the chassis with respect to the road surface. and has. This displacement suppression mechanism rotates the boom relative to the chassis in order to apply vibration to the boom that has a phase different from the normal vibration of the chassis relative to the road surface.

In one embodiment of the invention, an auxiliary spring and dump mechanism is provided within the boom hoist cylinder. Instead of being fixed to the chassis, the boom can be rotated within a certain range around a horizontal axis. However, this rotation is resisted by an auxiliary spring, and the dump mechanism controls the rate of compression or recovery of this spring. According to this displacement suppressing mechanism, the compression or restoring speed of the spring is controlled by the dump mechanism, and the force applied to the axle is rapidly consumed as heat. The location of the pivot shaft and the auxiliary spring, and the characteristics of the auxiliary spring and dumping mechanism are appropriately selected so that a controlled mode of vibration is produced in the weight part relative to the chassis. The amplitude of the vertical displacement of the weight part and its appendages is controlled by adding a dumping mechanism to the auxiliary spring.

According to the invention, large vibrational displacements and accelerations of an elastically supported chassis are reduced. It is particularly advantageous for the invention to be applied in cases where it is not economically possible to provide a dumping action by providing conventional shock absorbers for the axle springs on vehicles such as large mobile cranes.

By providing the dynamic stabilization mechanism of the present invention on the crane boom on the chassis, various effects not previously available can be obtained. For example, even when the vehicle runs on the road or accelerates or decelerates, the chassis and the boom on it will not vibrate excessively or move up and down, making the vehicle run safely, extending its life, and preventing damage to the driver. Never. Since the dump mechanism is constructed from parts attached to the vehicle such as a boom hoist cylinder, costs can be reduced. The spring and damping mechanisms can be easily adjusted according to different vehicle and road conditions. The fluidic and electrical control system is relatively simple in construction, uses a variety of conventional components, and is easy to assemble and operate.

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2, reference numeral 10 indicates a self-propelled vehicle such as a mobile crane, and a telescoping crane boom 12, which is a large weight part, is supported on a chassis 18 of this vehicle. The vehicle 10 of the present invention prevents the chassis 18 and crane boom 12 from moving or bouncing with respect to the road surface T due to rapid acceleration or deceleration of the vehicle 10 or in response to dynamic loads generated from unevenness of the road surface T on which the vehicle travels. It has a dynamic stabilization mechanism. The vehicle generally has a lower section 14 mounted thereon by a rotating ring member 16 for rotation in either direction within a limited range about a vertical axis 17 during crane operation. and an upper portion 15.

The lower part 14 has a chassis 18 with four wheels 20, a fixed ring 21 of said rotating ring member 16, and an outrigger 22 which is deployed during crane operation, for producing power for the crane and for driving the wheels 20. an engine 23 for generating power; a battery 24 for the engine 23;
and a fluid reservoir 25 for supplying operating fluid to the wheels and crane.

The upper part 15 has a rotatable ring 28 of the rotating ring member 16 and a support frame 30 fixed to this ring 28. A boom support member 32 is secured on the support frame 30 and pivot pins 35 allow the crane boom 12 to pivot about a horizontal axis 36 into raised and lowered positions during crane operation.
The support frame 30 is mounted on the support frame 30 by a pivot mechanism 34 that includes a pivot mechanism 34 . Crane boom 12 includes a base boom section 40, an inner boom section 41 insertable within base boom section 40, and an outer boom section 42 insertable within inner boom section 41.
and at least one fluid ram (not shown) for extending and retracting the boom sections 41,42.
The support frame 30 supports a cable winch 37, a counterweight 38 and a driver's cab 39.

A pair of boom hoist cylinders 45 are connected to the support frame 30 and the base boom section 40, respectively, for raising and lowering the crane boom 12;
Moreover, each cylinder 45 has a dynamic stabilization mechanism.

The wheels 20 for the chassis 18 of the lower part 14 of the vehicle 10 include a shaft 48, a wheel 50 rotatably mounted on the shaft 48, and a large elastic low pressure wheel 50 attached to the wheel 50 that engages with the road surface T. (balloon) tire 52. The shaft 48 is attached to the chassis 18 such that it is capable of rotational and steering movements but cannot move up and down relative to the chassis 18. However, the tire 52 is capable of elastically compressing downwardly to some extent in response to downward loading by the lower and upper portions 14, 15 of the vehicle 10. Tire 52 is resiliently recoverable when such vertical loads are removed. As a result, the tire 52 has a chassis 18
The chassis 18 functions as an elastic support mechanism, and can elastically move vertically and arcuately in the directions of arrows A and B shown in FIG. 3 according to the road surface T.

Vehicle 10 is self-propelled, with one or more axles 48 being driven by engine 23 via a suitable transmission (not shown). Two or four axes 48 are steered by suitable steering mechanisms (not shown). However, the present invention is applicable to trailer-type vehicles (not shown) that are not self-propelled and are moved by another vehicle, such as a truck (not shown).
It can also be applied to mobile cranes mounted on top. Furthermore, instead of using elastic tires 52 to absorb the vertical motion between the chassis 18 and the road surface T, a conventional spring shock absorber can be used as needed to absorb the vertical motion between the chassis 18 and the road surface T. Each axle 48 may be connected to the chassis 18 by an axle spring (not shown).

A pair of boom hoist cylinders 45 operate to move crane boom 12 up and down about pivot pin 35. Each boom hoist cylinder 4
5 has its lower end connected to the first
The upper end of the boom support member 32 is connected to the point P1 of the boom support member 32 shown in FIGS.
2 by an upper pivot pin 55. Each boom hoist cylinder 45 constitutes the dynamic stabilization mechanism of the present invention.

In the operator's cab 39 there are control levers and switches for actuating the stabilizing mechanism, and for driving and steering the vehicle 10, for operating the upper part 15 of the crane and the crane boom 12, and for operating the outriggers 22. There are conventionally known control mechanisms for operation.

As shown in FIGS. 3-6, the dynamic stabilization mechanism includes at least one member connected between the chassis 18 and the crane boom 12 to resist vertical and swinging motion between the two.
a hollow piston rod 80 and a piston 112 in the hollow piston rod 80 parallel to each auxiliary spring 60;
It has a dump mechanism 62 including a fluid orifice that suppresses the movement of the spring. In the embodiment shown in FIGS. 5 and 6, an auxiliary spring 60 and a dump mechanism 62 are disposed within a boom hoist cylinder 45 provided to move the crane boom 12 up and down.

In the present invention, instead of being fixed to the chassis 18, the crane boom 12 is mounted around a horizontal pivot pin 35 in the pivot mechanism 34 when the vehicle 10 tends to move up and down and rock while traveling on the road surface T. It can be rotated and swung freely. However, this rotation of the crane boom 12 is controlled by the auxiliary spring 60 and the dump mechanism 62. The device of the present invention has an auxiliary spring 6 so that the load applied to the shaft 48 at maximum speed is dissipated as heat.
The best results are obtained by selecting zero force, the restraining force of the dump mechanism 62, and the relative positions of the pivot pin 35, the auxiliary spring 60, and other components. The location of the pivot pin 35, the auxiliary spring 60, and the characteristics of the spring and dump mechanism are selected to replace uncontrollable vibration modes of the chassis 18 with modes that are dynamically coupled to the movement of the crane boom 12. . The amplitude of the chassis 18 can be controlled by restraining the auxiliary spring 60.

As shown in FIGS. 5 to 7, the boom hoist cylinder 45 includes a cylinder housing member 63 that does not move in the axial direction and a main piston 78 that is movable in the axial direction. Cylinder housing member 63 includes a hollow outer cylinder 66 having an end cap 68 secured to one end thereof and a piston rod seal 70 within the other end. Each end cap 68 has a fluid hole 72 that communicates with one chamber 73 within the hollow outer cylinder 66. Hollow outer cylinder 66 has a fluid hole 74 that communicates with another chamber 75 within hollow outer cylinder 66 . The main piston 78 is slidable within the bore of the hollow outer cylinder 66. The main piston 78 is connected to a hollow piston rod 80 that extends outwardly from the other end of the hollow outer cylinder 66 through a hole 82 in the piston rod seal 70.

When pressurized fluid is supplied to chamber 73 in hollow outer cylinder 66 through fluid hole 72, main piston 78 and hollow piston rod 80 are shifted to the boom hoist cylinder extended position, crane boom 12 is raised, and fluid is supplied to chamber 73 in hollow outer cylinder 66. Chamber 75 via 74
is discharged from. Conversely, when pressurized fluid is supplied through the fluid hole 74 into the chamber 75 in the hollow outer cylinder 66, the main piston 78 and the hollow piston rod 80 are shifted to the boom hoist cylinder retracted position, and the crane boom 12 is lowered. Fluid is exhausted from chamber 73 via fluid hole 72 .

Boom hoist cylinder 45 thus operates to raise and lower crane boom 12 in response to the action of the fluid control system shown in FIG. This control system has three manually operable neutral, up, and down control systems for connecting fluid holes 72 and 74 in hollow outer cylinder 66 to fluid reservoir 25.
It has a position boom hoist direction selection valve 85. The control system further includes a valve member 86 shown in FIGS. 5, 8, and 9. This valve member 86 is a holding valve 9
2, a shiftable spool 94A and a restraining member 9
4B, and a solenoid operated check valve 96. When the selection valve 85 is shifted from the neutral position shown in FIG. 5 to the raised position, the pump 8 driven by the engine 23
7 receives fluid from the fluid reservoir 25 and pumps it through fluid line 89, the one-way check valve 90 portion of retention valve 92, and fluid line 91 to fluid hole 72 in hollow outer cylinder 66 so that the boom hoist cylinder is extended. be done. At the same time, fluid from the fluid hole 74 of the hollow outer cylinder 66 flows into the fluid line 9.
3, flows to fluid reservoir 25 via shuttle valve 94, fluid line 95 and selection valve 85.

When the selection valve 85 is shifted from the neutral position to the down position, the pump 87 receives fluid from the reservoir 25 and pumps it through the selection valve 85, the shuttle valve 94, and the fluid line 93 to the fluid hole 74 of the hollow outer cylinder 66. , the boom hoist cylinder is retracted. At the same time, fluid from the fluid hole 72 of the hollow outer cylinder 66 is transferred to the holding valve 92, fluid line 89, which is shifted to the open position when fluid lines 91 and 95 are pressurized and pilot pressure is applied through the passageway 100. and flows to fluid reservoir 25 via selection valve 85 .

As shown in FIG. 5, when the selection valve 85 is in the neutral position, the holding valve 92 is in the closed position and fluid is flowing into the chamber 73.
This prevents the boom hoist cylinder 45 from being inadvertently retracted by the weight of the crane boom 12 or other objects.

A dynamic stabilization mechanism is provided on the boom hoist cylinder 45 as shown in FIGS. 3-6. Hollow piston rod 80 is hollow and has a bore 102 closed at the outer end of hollow piston rod 80 by an end cap 104 secured to the rod. The bore 102 is closed at the inner end of the hollow piston rod 80 by a fixed end plate 106. The support ring 103 is connected to the hole 10 of the hollow piston rod 80.
2 and is located and fixed between the end cap 104 and the end plate 106. Support ring 103 has hole 10
9, and a cylindrical spring guide 110 is slidable into this hole 109. Support ring 1
03 has a gas passage 103A therein.

A piston 112 is secured to one end of the spring guide 110 by a set screw 114 and is slidable within a bore 102 in the hollow piston rod 80. A hollow tubular spacer 116 is provided within the bore 102 and is connected at one end to the support ring 103 and at the other end to the end cap 104. Spacer 116 serves to insert and position support ring 103 within hole 102 . A plurality of dish-shaped spring washers 117 serve as the spring guide 110.
6, which fills the gap between support ring 103 and piston 112 and is slightly compressed in the position of FIG.

The spring washer 117 corresponds to the auxiliary spring 60 described above. The innermost end of the hollow piston rod 80 has a passage 12 passing through the end plate 106.
0 is provided to provide communication between the chamber 122 in the bore 102 between the end plate 106 and the piston 112 and the fluid chamber 75 in the hollow outer cylinder 66. Room 122 is the fifth
As shown in FIG. Hollow piston rod 80 further has a chamber 124 occupying a portion of bore 102. Chamber 124 is T-seal 1 on piston 112
25 from chamber 122 and plug 1
End cap 1 closed by 31'
04 is filled with a pressurized gas, such as nitrogen, which is initially introduced through passage 130'. The pressurized gas is maintained at a pressure of approximately 800 psi within a boom hoist cylinder 45, which may have an unextended length of, for example, ^{approximately} 12 feet. This pressurized gas is applied to the spring washer 11.
7 does, thus allowing a smaller, weaker washer 117 to be used to constrain the piston 112 to the left side in FIG. 6 and thus apply a constant pressure to the piston 112.

As shown in FIGS. 5 and 8 to 10, the check valve 96 has valve holes 130, 131 and a passage 132.
, one-way check valve 133 , and valve holes 130 and 1
A bias spring 134 restrains one-way check valve 133 between valve holes 130 and 131, and a solenoid 135 is energized to shift passageway 132 between valve holes 130 and 131. This solenoid attachment,
Deenergization is accomplished by an electrical control circuit shown in FIG. When the solenoid 135 is energized, after the crane boom 12 is lowered to a load transfer position approximately 10° above the lowest horizontal position by operating the selection valve 85, the stabilization mechanism in the boom hoist cylinder 45 is activated and the selection valve 85 is activated. 85 returns to the neutral position shown in FIG. The passage 13 is energized by the solenoid 135.
2 is shifted between valve holes 130 and 131, and spool 94A in shuttle valve 94 is shifted to the right in FIG. A fluid circuit is established from 73 through line 91, passage 132 in check valve 96, shuttle valve 94, line 93 and fluid hole 74 to chamber 75 of hollow outer cylinder 66 of boom hoist cylinder 45.

Chamber 75 communicates with chamber 122 of hollow piston rod 80 via passage 120. Therefore, vehicle 10
When the crane boom 12 rotates around the pivot pin 35 and therefore relative to the chassis 18, the fluid in the closed circuit chamber 75 enters the chamber 122 depending on the direction of rotation of the boom. Washiya 1
17, that is, the auxiliary spring 60 is released or compressed depending on the rotation direction. The value of the design minimum diameter of the passages 120, 132 controls the rate of fluid flow within the system and therefore the auxiliary spring 6.
It plays a role in controlling the rate at which zeros can be compressed or released. As a result, movement of the crane boom 12 relative to the chassis 18 is suppressed.

As shown in FIG. 10, the electrical control circuit for the solenoid 135 of the check valve 96 connects a power source such as a battery B, a normally open limit switch 150 responsive to boom position, and a panel 149 provided on a normally open relay 152. have The relay 152 has a normally open relay contact 153 and a relay coil 154, and a normally open relay contact 153 and a relay coil 154.
Rocker switch 156 with on, engaged position
, Leedaylight 158, and Onlight 160
and has. As shown in FIGS. 10 and 14, the rocker switch 156 includes two switch levers L1, L2 and six terminals T1, which are operated by turning a manually operable toggle button 166 into the off, on, and engaged positions. ~T6. In the off position, lever L1 contacts terminals T2 and T3, and lever T2
is in contact with terminals T5 and T6. In the on position, lever L1 contacts terminals T2 and T3, and lever L2 contacts terminals T4 and T5. In the engaged position, the lever L1 contacts the terminals T1, T2, and the lever L2 contacts the terminals T4, T2.
Touches T5. Battery B has a ground terminal and another terminal connected to one end of a limit switch 150 located within the crane boom 12 and closed when the boom tilts less than 10 degrees. The other end of limit switch 150 is connected to one end of relay contact 154 via wire 162. Relay contact 15
The other end of 4 is connected to terminal T5 via wire 164. Wire 162 is connected to terminal T2 via wire 170. Relay coil 164 has a ground terminal and other terminals connected to terminals T1 and T4 via wires 172 and 173, respectively. Solenoid 135 is connected to terminal T4 via wire 174.
and a ground terminal. On-light 160 is connected between wire 174 and ground, rocker switch 156 is in the engaged position, and
Lights up when relay contact 153 is closed and solenoid 135 is energized. A reader light 158 is connected between wire 162 and ground and illuminates when limit switch 150 is closed.

When the crane boom 12 is rotated 10 degrees from its lowest position, the limit switch 150 closes and the read day light 158 turns on. When rocker switch 156 is off or on, relay coil 154 and solenoid 135 remain deenergized.
When rocker switch 156 is in the engaged position, relay coil 154 is energized, relay contact 153 closes and energizes solenoid 135, activating the stabilizing mechanism described above.

The relational symbol for each part shown in FIG. 4 indicates that the middle distance is feet, and the weight is slug. Here, slag = pound/acceleration of gravity (32.2).

L1 is the horizontal distance between the front wheel shaft 48 and the pivot pin 35 L2 is the horizontal distance between the pivot pin 35 and the rear wheel shaft L3 is the distance between the pivot pin 35 and the center line of the cylinder 45 L4 is the pivot pin 35 and the center of gravity of the chassis 18 and its attachments M1 is the mass of the chassis 18 and its attachments J1 is the moment of inertia around the axis passing through the center of the mass M1 M2 is the mass of the crane boom 12 and its attachments J2 is the moment of inertia about the axis passing through the center of mass M2 θ1 is the rotation angle of the chassis 18 θ2 is the rotation angle of the crane boom 12 K1 to K3 are the corresponding spring rates (lb/ft) C1 to C3 are the restraint rates ( (pounds x seconds/feet) Sum of 〓F(M1+M2) K1*L1+K2*L2) θ¨+For+AK1*Y+AK2*Z=0.0 〓M1(-M1*L4)x+(J1+M1*L4 ² )θ1- (C1×L1+C2*L2)X〓+(C1*L1 ² +C2*L2 ² +C3*L3 ² )θ〓1−(C3*L3 ² )θ〓2(K1*L1+K2*L2)x+(K1*L1 ² +K2*L2 ² +K3*L3 ² )θ1−(K3*L3 ² ) θ2+TOR− (K1*Y*L1+K2*Z*L2)=0.0 〓M2(−M2*L5)X¨+(J2+M2*L5 ² )θ¨2− (C3*L3 ² )θ〓1+(C3*L3 ² )θ〓2(−K3* ^L32 )θ1+(K3* ^L32 )θ2=0.0 In special cases involving a mobile crane of a given size and weight and the input variables shown below, the analysis using the Jacobi method Thus, Eigen values representing the three vibration frequencies and Eigen vectors representing the three modes of vibration are obtained. The three frequencies No. 1 to No. 3 shown below relate to the vertical displacement X and rotation angles θ1 and θ2.
Matrices A and B shown below are intermediate in the process of obtaining Eigen values and vectors. The node positions shown below indicate points away from the boom pivot when the boom pivots about the pivot but does not move vertically.

Input displacement AK1~AK3, AL1~AL5, AM
1, AJ1, AM2, AJ2 are respectively: 132000.00 132000.00 200000.00 11.5000 1.0800 4.600 3.6300 14.5800 1240.90 74543.00 388.90 34481.00 The following shows matrix A : 264000.000 −1660560.0000 0.0 −1660560.000 21842964.8000 −4232000.0000 0.0 −4232000.0000 4232000.0000 The following shows matrix B: 1629.8000 −4504.4670 −5670.1620 −4504.4670 90894.2152 0.0 −5670.1620 0.0 117151.9620 Frequency No. 1 is 1.5322Hz Eigenvector is 0.9768 0.0957 0.0164 Machine node position is 10.211 Boom node position is 59.618 Amplitude ratio Theta 1/Theta 2 is 5.836 Frequency No. 2 is 2.6845Hz Eigenvector is -4.7572 0.8560 -0.3882 Machine node position is -5.557 Boom node position is 12.255 Amplitude ratio Theta 1 / Theta 2 is -2.205 Frequency No. 3 is 0.7984Hz Eigenvector is 1.9159 0.3686 1.0030 Machine node position is 5.197 Boom node position is 1.910 Amplitude ratio Theta 1/Theta 2 is 0.368 Figure 5 shows vibrations occurring in a mobile crane to which the present invention is not applied, and Figure 16 shows vibrations in a mobile crane to which the present invention is applied. According to the above, vibration can be suppressed by providing a phase difference in the rotation between the chassis and the boom.

[Brief explanation of drawings]

Fig. 1 is a side view of a mobile crane equipped with the dynamic stabilization mechanism of the present invention, Fig. 2 is its front view, and Fig. 3
Figure 4 is an explanatory diagram of each part, Figure 5 is an explanatory diagram of the crane boom's boom hoist cylinder and its fluid control circuit, Figure 6 is an enlarged cross-sectional view of the boom hoist cylinder, and Figure 7 is an explanatory diagram of the boom hoist cylinder of the crane boom. The figure is a 7-7 line view in Figure 6, Figure 8 is a side view of the valve member,
9 is a sectional view taken along the line 9-9 in FIG. 8, FIG. 10 is an electrical control circuit diagram, FIG. 11 is a front view of the panel, FIG. 12 is a side view thereof, and FIG. 13 is a rear view thereof. FIG. 14 is an explanatory diagram of the rocker switch, FIG. 15 is a graph showing the vibration of a conventional crane, and FIG. 16 is a graph showing the vibration of the crane of the present invention. 10... Vehicle, 12... Crane boom, 16
... Rotating ring member, T ... Road surface, 18 ... Chassis, 20 ... Wheel, 22 ... Outrigger, 2
3...Engine, 25...Fluid reservoir, 39...
...Driver's cab, 45...Boom hoist cylinder, 4
8... Axis, 52... Tire, 60... Auxiliary spring, 62... Dump mechanism, 72, 74... Fluid hole, 73, 75, 122, 124... Chamber, 78...
... Main piston, 80 ... Hollow piston rod, 85 ... Selection valve, 86 ... Valve member, 87 ...
Pump, 90...one-way check valve, 92...holding valve, 112...piston.

Claims (1)

[Scope of Claims] 1. A first heavy object including a chassis 18 of a vehicle, and an elastic member including wheels 52 connected to the chassis 18 and supporting the chassis 18 so as to be movable up and down and rotatable relative to the road surface. a support mechanism and a portion 12 supported by the chassis 18;
a second heavy object including: a mechanism 15 for movably connecting the portion 12 to the chassis 18 and allowing the portion 12 to move up and down and rotate relative to the chassis 18; and the chassis 18. a lift mechanism 45 selectively operated to vertically move the section 12 relative to the chassis 18 provided between the sections 12; or a restraining mechanism for reducing vertical movement and rotation of the chassis 18 relative to the road surface in response to dynamic loads applied to the vehicle due to acceleration and deceleration of the vehicle, and the lift mechanism 45 One end is connected to the chassis 18.
an outer cylinder 66 connected to the outer cylinder 66 and two chambers 73, 75 that are slidable within the outer cylinder 66;
a hollow piston rod 80 connected to the main piston 78 and extending outward from the other end of the outer cylinder 66 and connected to the portion 12;
a mechanism for supplying fluid into the chambers 73, 75 for operating the hollow piston rod 80;
a piston 112 that is slidable within the hole 102 and partitions the hole 102 into two chambers 122, 124; a spring mechanism 60 for limiting relative vertical movement and rotation of the portion 12; and a piston 112 connected to the spring mechanism 60 for reducing the speed of movement of the spring mechanism 60 as rapidly as possible to reduce dynamic loads. one chamber 75 in the outer cylinder 66 and the piston for supplying fluid to the chamber 122 in the hole 102 against the bias mechanism; hole 102
A passage 120 that communicates between one chamber 122 in the
A vehicle having a displacement suppression mechanism. 2 the bias mechanism is connected to the piston rod 80;
A vehicle having a displacement suppressing mechanism according to claim 1, wherein the displacement suppressing mechanism is pressurized gas introduced into the other chamber 124 within the inner hole 102. 3. A patent claim in which the chassis 18 and the portion 12 move up and down at a certain vibration frequency, and the suppression mechanism creates vibrations at a frequency with a phase different from the frequency, and as a result, the vibrations of the chassis 18 are suppressed. A vehicle having a displacement suppressing mechanism according to item 1 or 2.