JP2003172303A - Hydraulic system, method for controlling the same, and x-ray ct device using hydraulic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic system having high cylinder supporting rigidity against force in any direction with a small scale and a low cost. <P>SOLUTION: In a hydraulic system supporting a designated load weight with a rod directly connected to a piston of a double acting cylinder in which the piston is a border and hydraulic pressure is applied in both directions of a cap side and a head side, and driving the rod in a vertical direction against the load weight or for the load weight, a first hydraulic passage guiding pressure oil from a hydraulic pump to the cap side via a first and a second selector valve, a second hydraulic passage returning oil pushed out from the cap side by the load weight to a reservoir tank side via the second selector valve and a third selector valve, a third hydraulic passage connecting the third selector valve and the head side, and a fourth hydraulic passage guiding pressure oil from the hydraulic pump to the head side via the second selector valve. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic system, a control method therefor, and an X-ray CT apparatus using the hydraulic system. More specifically, the present invention relates to a compound system in which hydraulic pressure acts in both the cap side and the head side of a piston. The present invention relates to a hydraulic system for driving a moving cylinder, a control method therefor, and an X-ray CT apparatus using the hydraulic system.

[0002]

2. Description of the Related Art Generally, a hydraulic system is widely used as an actuator which is small in size, inexpensive, and has a low operating noise and a large output.

A hydraulic system used in a tilt mechanism of a gantry device in an X-ray CT (Computerized Tomography) device is one of them. What is an X-ray CT system?
The subject (patient) is irradiated with X-rays from an X-ray tube, the difference in the X-ray absorption rate of human tissues such as organs, blood, and gray matter is detected by an X-ray detector, and this is imaged by computer processing. The image (X-ray tomographic image) of the tomographic plane (plane at the slice position, that is, slice plane) of the target region is obtained. Further, the tilt mechanism of the gantry device is a mechanism for tilting the gantry, which is equipped with an X-ray tube and an X-ray detector, and includes a gantry rotating unit that rotates around the subject, in a forward or backward direction. The tilt mechanism makes it possible to capture X-ray tomographic images at various angles with respect to the subject.

Up to now, a hydraulic system using a single-acting cylinder in which a hydraulic pressure acts only in one direction has been used for a tilt mechanism of a gantry apparatus in an X-ray CT apparatus.

On the other hand, in the X-ray CT apparatus, the rotation speed of the gantry rotating part is increasing year by year, and vibration due to the imbalance of the weight of the gantry rotating part tends to increase. In addition, the slice thickness is becoming thinner, and vibration during imaging is becoming a cause of image quality deterioration.
Therefore, a hydraulic system capable of suppressing vibration is desired.

On the other hand, in the above-described hydraulic system using a single-acting cylinder, since the hydraulic pressure works only in one direction, the cylinder support rigidity in a predetermined direction (pulling direction) is low. For this reason, when the vibration caused by the imbalance of the gantry rotating portion becomes large, cavitation (a phenomenon in which the gas dissolved in the working oil becomes bubbles in the low pressure portion to form a cavity) occurs in the cylinder, causing the cylinder to move to the low pressure side ( There is a problem such as stretching in the tensile direction), and it was not suitable for suppressing vibration.

In this regard, the applicant of the present application has already proposed a hydraulic system (X-ray CT apparatus) in which the hydraulic cylinder used for the tilt mechanism is a double-acting type (the hydraulic pressure acts in both directions) (Japanese Patent Application No. 10- 85338). The contents are shown below in Figure 1.
Outline according to 7,18.

FIG. 17 (A) shows a side view of an imaging table and a gantry device of an X-ray CT apparatus.
Reference numeral 20 is an imaging table, 21 is a top plate (cradle) on which the subject 100 is mounted and is movable in the body axis (CLb) direction, 3
Reference numeral 0 denotes a gantry that rotatably supports an X-ray imaging system including an X-ray tube, a collimator, and an X-ray detector (not shown) around the body axis of the subject 100, and 34R is fixed to both side surfaces of the gantry 30. A semi-circular rail member (however, 34R on the right side is visible in the figure), 31 is a base for supporting the gantry 30 via the rail member 34R, and 32R
Is a roller bearing that is provided on the base 31 and slidably supports the rail member 34R, 61R is a double-acting hydraulic cylinder bridged between the base 31 and the rail member 34R, and 62R is its rod (movable arm). )
Is.

FIG. 17A shows a state in which the gantry 30 is supported in a substantially vertical (neutral) posture. A part of the weight of the gantry 30 is added to the rod 62R in this state. Therefore, as shown in FIG. 17B, when the gantry 30 is tilted in the front (FWD) direction, the double-acting hydraulic cylinder 61R is used. Contracts with the weight of the gantry 30, and as shown in FIG. 17C, when the gantry 30 is tilted in the rear (BWD) direction, the double-acting hydraulic cylinder 61R extends in the direction of being opposed to the weight of the gantry 30. is there.

FIG. 18 shows a circuit diagram of a hydraulic system for tilting the gantry 30. In the figure, CYL, C
YR is a left and right double-acting hydraulic cylinder, and V1 to V6 are solenoid valves. The gantry 30 can be tilted forward / backward at two speeds under the control of the valve controller VC.

To be more specific about control, first, the gantry 3
When the angle of 0 is not changed, all the valves V1 to V6 are closed.

Next, tilt the gantry 30 rearward,
When the current tilt angle is on the rearward tilt limit side, only the valves V1 and V6 are opened and the others are closed. In this state, the hydraulic oil is press-fitted from the valve V1 into the cap side cylinder chamber, the hydraulic oil in the head side cylinder chamber is discharged from the valve V6, and the gantry 30 tilts at a low speed. On the other hand, when the current tilt angle is not on the backward tilt limit side, the valves V1, V2 and V6 are opened and the others are closed.
In this state, the hydraulic oil is pressed into the cap side cylinder chamber from the valves V1 and V2, and the hydraulic oil in the head side cylinder chamber is discharged from the valve V6, so that the gantry 30 tilts at a high speed.

Next, when the gantry 30 is tilted forward and the current tilt angle is not on the forward tilt limit side, the valves V3, V4 and V5 are opened and the others are closed. In this state, the working oil is press-fitted into the head side cylinder chamber from the valve V3, and the working oil in the cap side cylinder chamber is discharged from the valves V4 and V5, so that the valve tilts at a high speed.
Further, when the current tilt angle is in the forward tilt limit side portion, the valve is ejected only from the valve V4, so that the tilt is performed at a low speed.

[0014]

However, even when the double-acting hydraulic cylinder as described above is used, there are the following problems regarding the cylinder support rigidity.

(1) When tilting backward, hydraulic oil is press-fitted into the cap side cylinder chamber to open the head side cylinder chamber, so that the rod returns to the original direction (the hydraulic oil inside the cap side cylinder chamber is compressed). The cylinder support rigidity is high for the force acting in the direction
The cylinder support rigidity is low with respect to the force acting in the direction in which the rod further extends (that is, the pulling direction).

(2) Similarly, when tilting forward, hydraulic oil is press-fitted into the head side cylinder chamber to open the cap side cylinder chamber, so that the cylinder supporting rigidity is high against the force acting in the pulling direction. However, the cylinder support rigidity is low with respect to the force acting in the compression direction.

Further, when the double-acting hydraulic cylinder as described above is used, compared with the conventional hydraulic system using the single-acting hydraulic cylinder, there are the following problems in cost and device scale. Occurs.

(3) The hydraulic pump pressurizes the hydraulic oil not only when it is tilted backward but also when it is tilted forward, so that the hydraulic pump frequently operates and power consumption increases.

(4) Not only when tilting backward, but also when tilting forward, the hydraulic oil is pressed into the hydraulic pump, so that the oil temperature easily rises and the operating speed changes greatly. In order to suppress the rise in oil temperature, it is necessary to increase the amount of oil in the oil tank, which leads to an increase in size of the device.

(5) When tilting forward, in addition to the weight of the gantry, the hydraulic pressure in the head side cylinder chamber (the discharge pressure from the hydraulic pump) is added to the cap side cylinder chamber, and the cap side cylinder chamber and its Since the hydraulic pressure in the passage increases, the pressure resistance of the cylinder, hydraulic parts, and piping must be increased, which is costly.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a hydraulic system having a high cylinder supporting rigidity against a force in an arbitrary direction at a small scale and at low cost.

[0022]

A hydraulic system of the present invention for solving the above-mentioned problems has the following structure when described in accordance with a first embodiment described later. That is, the required load weight is supported by the rod directly connected to the piston of the double-acting cylinder where hydraulic pressure acts in both the cap side and the head side with the piston as a boundary, and the rod is supported against the load weight or together with the load weight. In a hydraulic system driven in an up / down direction, a first hydraulic path for guiding pressure oil from a hydraulic pump to the cap side via first and second switching valves (check valve 323, double solenoid valve 321) A second hydraulic path for returning the oil pushed out from the cap side by the load weight to the reservoir tank side through the second switching valve (double solenoid valve 321) and the third switching valve (double solenoid valve 322). , A third hydraulic path connecting the third switching valve (double solenoid valve 322) and the head side, and a hydraulic pressure The pressure oil from the pump via the second switching valve (Double solenoid valve 321) and a fourth hydraulic passage leading to the head side.

Further, another hydraulic system of the present invention for solving the above-mentioned problems has the following constitution when described in accordance with a second embodiment described later. That is, the required load weight is supported by the rod directly connected to the piston of the double-acting cylinder where hydraulic pressure acts in both the cap side and the head side with the piston as a boundary, and the rod is supported against the load weight or together with the load weight. In the hydraulic system driven in the up / down direction, a first hydraulic path for guiding the pressure oil from the hydraulic pump to the cap side via the first and second switching valves (check valve 725, single solenoid valve 721). A second hydraulic path for returning the oil pushed out from the cap side by the load weight to the reservoir tank side via the second switching valve (single solenoid valve 721) and the third switching valve (single solenoid valve 723) And a fourth switching valve (thin valve) between the third switching valve (single solenoid valve 723) and the head side. A third hydraulic path connected via a solenoid valve 724) and a fourth hydraulic path that guides pressure oil from the hydraulic pump to the head side via a fifth switching valve (single solenoid valve 722). Equipped with.

Further, another hydraulic system of the present invention for solving the above-mentioned problems has the following configuration when described in accordance with a third embodiment described later. That is, the required load weight is supported by the rod directly connected to the piston of the double-acting cylinder where hydraulic pressure acts in both the cap side and the head side with the piston as a boundary, and the rod is supported against the load weight or together with the load weight. In a hydraulic system driven in an up / down direction, a hydraulic pump capable of changing an oil discharge direction, and pressure oil from the hydraulic pump is passed through a first switching valve (check valve 923) to the cap side. To the reservoir tank via a second switching valve (single solenoid valve 921) to push the oil pushed out from the cap side by the load weight to the reservoir tank; The switching valve (single solenoid valve 921) and the head side are connected via a third switching valve (single solenoid valve 922). Comprising 3 a hydraulic path, and a fourth hydraulic oil passage in which the pressure oil from the hydraulic pump through the fourth switching valve (check valve 926) leading to the head side.

Further, another hydraulic system of the present invention for solving the above-mentioned problems has the following structure when described according to a seventh embodiment described later. That is, the required load weight is supported by the rods of the first and second double-acting cylinders of the two double-acting cylinders, where hydraulic pressure acts in both the cap-side and head-side directions with the piston as a boundary, while supporting the required load weight. In a hydraulic system that is driven upward / downward against weight or with load weight, pressure oil from a hydraulic pump is fed to first and second switching valves (first switching valve = single solenoid valve 1421, second switching valve). Valve = a first hydraulic path leading to the cap side of the first double-acting cylinder via a check valve disposed between the single solenoid valve 1421 and the single solenoid valve 1423, and a pressure from the hydraulic pump. Oil is added to the first and third
Switching valve (first switching valve = single solenoid valve 1
421, third switching valve = single solenoid valve 14
21 and a single solenoid valve 1422 through a check valve) and a second hydraulic path leading to the cap side of the second double acting cylinder, and the first double acting cylinder by the load weight. The oil pushed out from the cap side of the fourth switching valve (single solenoid valve 1
423) through a third hydraulic path for returning to the reservoir tank side, and the oil pushed out from the cap side of the second double-acting cylinder by the load weight through the fifth switching valve (single solenoid valve 1422). A fourth hydraulic path for returning to the reservoir tank side by means of a sixth switching valve (single solenoid valve) between the fourth switching valve (single solenoid valve 1423) and the head side of the first double-acting cylinder. 1426), and a fifth switching valve (single solenoid valve 1422) connected between the fifth switching valve (single solenoid valve 1422) and the head side of the second double acting cylinder. Valve 142
5) and a sixth hydraulic path connected to each other and pressure oil from the hydraulic pump to the eighth and ninth switching valves (eighth switching valve = single solenoid valve 1424, ninth switching valve =
A seventh hydraulic path leading to the head side of the first double-acting cylinder and a pressure oil from the hydraulic pump are introduced via a check valve disposed between the single solenoid valve 1424 and the single solenoid valve 1426. Via the eighth and tenth switching valves (eighth switching valve = single solenoid valve 1424, tenth switching valve = check valve arranged between single solenoid valve 1424 and single solenoid valve 1425), An eighth hydraulic path leading to the head side of the second double-acting cylinder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals denote the same or corresponding parts throughout the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. 3 is a configuration diagram of a main part of the X-ray CT apparatus according to the embodiment of the present invention, showing an application example of the hydraulic system according to the present invention to the X-ray CT apparatus. The X-ray CT apparatus is roughly divided into a gantry apparatus that performs an axial / helical scan of the subject 100 with an X-ray fan beam XLFB, an imaging table 20 on which the subject is placed and moved in the body axis CLb direction, a gantry apparatus and imaging. While performing remote control of the table 20,
An operation console unit 10 operated by an X-ray imaging technician (operator).

The gantry device can be further roughly divided into a gantry 30 and a pedestal portion (not shown) having a mechanism for supporting and tilting the gantry 30. In the gantry 30, 40 is a rotary anode type X-ray tube, 40A is an X-ray control unit, 50 is a collimator for limiting the X-ray exposure range (body axis CLb direction), 50A is a collimator control unit, and 90 is a channel. A large number (n = 1000) of X-ray detection elements arranged in the CH direction are arranged in, for example, two rows A and B in the body axis CLb direction (note that
An X-ray detector arranged in another row or three or more rows), and 91 is a data collecting unit that generates and collects projection data of the subject based on the detection signal of the X-ray detector 90. The X-ray tube 40, the collimator 50, the X-ray detector 9
An X-ray imaging system such as 0 is mounted on the gantry rotating unit 33. The gantry rotating unit 33 is supported by the gantry 30 so as to be rotatable around the body axis.

33A is a rotation control unit of the gantry rotating unit 33, 60 is an angle sensor for detecting the tilt angle of the gantry 30, 60A is a tilt control unit, and 80 is a hydraulic circuit unit for driving the gantry 30 to tilt. Also, shooting table 2
In 0, 21 is a top plate (cradle) on which a subject is mounted and is movable in the body axis direction.

Further, in the operation console section 10, 1
Reference numeral 1 is a central processing unit for performing main control / processing (scan control, X-ray tomographic image reconstruction processing, gantry tilt control, etc.) of the X-ray CT apparatus, 11a is its CPU, and 11b is CPU1.
Main memory composed of RAM, ROM, etc. used by 1a (M
M), 12 is a command and data input device including a keyboard and a mouse, 13 is a display device (CRT) for displaying a scan plan, an X-ray tomographic image and the like, and 14 is a CPU 11a, a gantry device and an imaging table 20. A control interface for exchanging various control signals CS, monitor signals MS, etc. between them, 15 is a data collection buffer for temporarily storing projection data from the data collection unit 96, and 16 is storage for projection data from the data collection buffer 15. A secondary storage device (hard disk device or the like) that stores various application programs necessary for operating the X-ray CT apparatus, data files for various calculations / corrections, and the like.

The operation of X-ray CT imaging will be outlined.
X-ray fan beam XLFB from 40
Pass through and simultaneously enter the detector rows A and B of the X-ray detector 90.
To do. The data acquisition unit 91 is a corner detector array of the X-ray detector 90.
Projection data g corresponding to output _A(X, θ), g_b(X,
θ) and store them in the data collection buffer 15.
To do. Where X is the detector channel number and θ is the view
Represents a corner. Furthermore, the gantry rotating part 33 slightly rotated.
X-ray projection similar to the above is performed at each view angle θ, and
It collects and accumulates projection data for one rotation of the rotation unit.
At the same time, it follows the axial / helical scanning method.
Move the top plate 21 intermittently / continuously in the direction of the body axis CLb.
Then, these are stored in the secondary storage device 16. And C
PU11a, after the completion of all the above scan, or scan
Following the execution (in parallel), based on the obtained projection data
An X-ray tomographic image of the subject is reconstructed and displayed on a display device (CR
T) 13 is displayed.

FIG. 2 is a structural view of the gantry device of the X-ray CT apparatus and the imaging table 20 according to the first embodiment of the present invention, and FIG. 2 (B) is a front view. In the figure, 35 is a support frame (also called a back plate) that rotatably supports the gantry rotating part 33, 94 is a ball bearing interposed between the support frame 35 and the gantry rotating part 33, and 92 is a gantry rotating drive device. , 93 is a belt for gantry rotation drive.

Semicircular rail members 34L and 34R are fixed to both side surfaces of the support frame 35. On the other hand, roller bearings 32L and 32R are provided inwardly on both side surfaces of the base 31 supporting the support frame 35,
Here, rail members 34L, 34 on the side of the support frame 35
Since R is slidably mounted, the gantry rotating portion 33 is supported so as to be tiltable around its tilt center Q. Further, the double-acting hydraulic cylinder 61 is provided on both sides of the base 31.
L and 61R are rotatably attached to their lower ends, and upper rods 62L and 62R and the rail member 3 are attached.
One end of each of 4L and 34R is connected by a link member.

In this example, the hydraulic pump unit 70 is provided on the photographing table 20 side, and the empty space of the photographing table 20 is effectively used. Hydraulic pump unit 70
The hydraulic pressure is used for driving the top plate 21 on the one hand, and is used for tilting the gantry 30 on the other hand. On the other hand, a hydraulic circuit unit 80 that switches the oil flow paths to the hydraulic cylinders 61L and 61R is provided on the gantry 30 side, and a hydraulic pipe is connected between them.
Therefore, the entire gantry 30 can be made compact.

The rods 62L, 62 in the present embodiment
It is assumed that a part of the weight of the gantry 30 is added to R through the entire tilt angle of the gantry 30. The tilting operation of the gantry 30 in this case is performed by driving / stopping the hydraulic pump unit 70 and switching control of the hydraulic oil flow direction in the hydraulic circuit unit 80. That is, when the gantry 30 is tilted in the front (FWD) direction, the hydraulic pump unit 7
0 is activated, pressure oil from the hydraulic pump is injected into the hydraulic cylinders 61L and 61R, and the rods 62L and 62L are
R is pushed up. On the other hand, when the gantry 30 is tilted in the backward (BWD) direction, the solenoid valve is opened while the hydraulic pump 70 remains stopped. At this time, the rods 62L and 62R are pushed down by the weight of the gantry 30, and the pressure oil in the hydraulic cylinders 61L and 61R is pushed back to the hydraulic pump portion 70 side (tank side). Note that the relationship between the tilt direction and the vertical movement of the rod in this embodiment is opposite to that of the X-ray CT apparatus shown in the related art, but this is due to the difference in the mounting direction of the rail members. , Not essential.

The tilt control unit 60A operates under online control based on the scan plan from the operation console unit 10 (CPU 11a) and under manual operation of a local tilt button (described later) provided on the gantry 30. Tilt control of the gantry 30 is performed, and this control is drive / stop control (ON / OF) for the hydraulic pump unit 70.
F) and switching control (SW) of the hydraulic oil flow direction with respect to the hydraulic circuit unit 80. Also, the tilt control unit 6
A tilt angle detection signal from the tilt angle sensor 60 is input to 0A, and based on this, the CPU 11a and the operator can accurately control the tilt angle of the gantry 30 as desired.

FIG. 5 shows an example of a screen on the operation console unit 10 for performing the tilting operation of the gantry 30 (500). The tilt operation is roughly classified into a "normal mode" and a "service mode" (details will be described later), and further divided into an "automatic mode" and a "manual mode", and switches corresponding to each are provided (501 to 501). 504).
When "automatic mode" is selected, "BWD direction" and "FWD direction" can be selected as tilt directions of the gantry 30 (506, 507), and after inputting a desired angle, the operation start button 510 is turned on. By doing so, it operates in the selected direction up to the angle set and input, and automatically stops.

On the other hand, when the "manual mode" is selected, the local tilt buttons (FWD direction tilt operation switch 601 and BWD direction tilt operation switch 602) shown in FIG. 6 can be operated. The local tilt button is installed on the control panel 600 of the gantry 30, and the tilt operation is continued while the operator presses a predetermined tilt button. Whether the manual mode is selected or the automatic mode is selected, the tilt angle detection signal from the tilt angle sensor 60 is displayed on the screen 500 (505 in the manual mode, 509 in the automatic mode). , The operator makes the gantry 3 by such display.
The current tilt angle of 0 can be known.

FIG. 3 is a circuit diagram of a hydraulic system according to the first embodiment of the present invention, showing a hydraulic circuit in the case where a double solenoid valve and a unidirectional hydraulic pump are combined.
In the figure, a double-acting hydraulic cylinder 61L and a hydraulic circuit 81L for operating the double-acting hydraulic cylinder 61L of the hydraulic circuit section 80 are collectively referred to as a left unit (3
40L). The left side unit 3
The right side unit (not shown) that operates in a pair with 40L is the same as the left side unit, and a description thereof will be omitted.

In the hydraulic pump 70 shown in FIG. 3, 314 is an oil tank (reservoir tank) for recirculating and storing hydraulic oil.
Reference numeral 11 is a unidirectional hydraulic pump, 313 is a filter for purifying hydraulic oil, 312 is an electric motor (M) for driving the unidirectional hydraulic pump, and 315 is a pressure control valve (relief valve) for controlling the hydraulic pressure applied to the hydraulic circuit 81L. ). In the double-acting hydraulic cylinder 61L, 331L is a piston, and the rod 62L is connected to the piston 331L. 334L is a drain for collecting the leaked oil. In addition, in this specification, for convenience of description, the piston 331L of the double-acting hydraulic cylinder 61L is in accordance with the JIS standard.
The side with the rod 62L is referred to as the head side, and the opposite side is referred to as the cap side with the border as the border. However, in the industry, the side with the rod 62L may be referred to as the rod side and the opposite side is referred to as the head side.

Further, in the hydraulic circuit 81L, 326 is a pressure control valve (relief valve) for limiting the hydraulic pressure applied to the system, 323 is a check valve (check valve), 321,
322 is a double solenoid valve having three positions, 32
Reference numerals 4 and 325 denote throttle valves (which may be of variable flow rate type) for limiting the oil flow rate.

The double-acting hydraulic cylinder 61L is divided into a head side cylinder chamber 332L and a cap side cylinder chamber 333L by a piston 331L. Piston 3
The 31L is directly moved by oil being taken in and out of the head side cylinder chamber 332L and the cap side cylinder chamber 333L.
The hydraulic oil sucked up from the oil tank 314 is pressed into the cap side cylinder chamber 333L by the unidirectional hydraulic pump 311 via the throttle valve 324, the check valve 323, and the double solenoid valve 321.

The double solenoid valve 321 has two coils. Depending on which coil is excited, the double solenoid valve 321 can be operated in the direction A or in the direction B in the figure. It controls the traveling direction of the oil inside. In the case of FIG. 3, a voltage is not applied to the double solenoid valve, and the hydraulic oil between the pipe P3-1 and the pipe P3-2 is shut off. In this state, the hydraulic oil in the cap side cylinder chamber 333 is in a sealed state, and the rod 62L is in a state in which it does not move in the BWD direction.

When the double solenoid valve 321 is operated in the A direction, it moves to the block on the right side in FIG.
3-1 is in a sealed state and the pipes P3-2 and P3-6
Is opened, so that the hydraulic oil sucked up from the oil tank 314 remains in the cap side cylinder chamber 331 in the state where the hydraulic oil is sealed in the throttle valve 324 and the check valve 32.
3, and is press-fitted into the head side cylinder chamber 332 via the double solenoid valve 321. This allows the rod 6
2L does not move in the FWD direction (cylinder support rigidity is high).

At this time, the cap side cylinder chamber 3
The hydraulic oil press-fitted into the 33 and the head side cylinder chamber 332 is discharged to the oil tank 314 by the relief valve 315 so that the hydraulic oil does not exceed a predetermined pressure. At this time, the relief pressure of the relief valve 315 is set to (set pressure of the relief valve 315)-(maximum axial force applied to the hydraulic cylinder 61L) / (head-side cross-sectional area of the hydraulic cylinder 61L). , Thereby, the head side cylinder chamber 332L
It prevents the internal pressure from becoming excessive.

On the other hand, the double solenoid valve 321 is B
Pipe P3-1 and pipe P3-2
And the hydraulic fluid sucked up by the unidirectional hydraulic pump 311 are pressed into the cap side cylinder chamber 333L,
The hydraulic oil enclosed in the cap side cylinder chamber 333L can be discharged.

Like 321, 322 is also a double solenoid valve, and can be operated in the A and B directions (A operation and B operation). Double solenoid valve 32 of FIG.
No. 2 indicates that no voltage is applied and the hydraulic oil between the pipe P3-3 and the pipes P3-4 and P3-5 is cut off from each other.

Further, the double solenoid valve 322 is set to A
Pipes P3-3, P3-4, P3-
5 communicates with each other, and as a result, when the hydraulic pump is stopped, the cap side cylinder chamber 33 discharged by the weight of the gantry 30 directly connected to the rod 62L.
It becomes possible for the hydraulic oil in 3 to enter the head side cylinder chamber 332 via the pipes P3-3 and P3-4.

On the other hand, set the double solenoid valve 322 to B
When it is operated in the direction, the hydraulic oil can flow from the pipe P3-4 to P3-5, and the head side cylinder chamber 33
2L is opened, and the hydraulic oil is discharged to the oil tank 314.

The operation of the hydraulic system shown in FIG. 3 will be described with reference to the time chart of FIG. On the gantry tilt operation operation screen 500 shown in FIG. 5, the normal mode, the automatic mode, and the FWD direction are selected (501, 50).
3, 507), after inputting a predetermined set value to 508, when the operation start button 510 is turned on, the FWD direction tilt start state is set, and the unidirectional hydraulic pump 311 operates (401),
The double solenoid valve 321 operates in the B direction (4
02). When the double solenoid valve 321 operates in the B direction as described above, the pipe P3-1 and the pipe P3-2 communicate with each other, so that the working oil sucked up from the oil tank 314 by the unidirectional hydraulic pump 311 is transferred to the cap side cylinder chamber. It is pressed into 333L.

On the other hand, simultaneously with this operation, the double solenoid valve 322 operates in the B direction (403), and the pipe P
Since it becomes possible to flow the hydraulic oil from 3-4 to the pipe P3-5, the head side cylinder chamber 332L is opened.

As a result, the head side cylinder chamber 332L
The hydraulic oil of is discharged to the outside of the cylinder as the piston 331L operates in the FWD direction when the hydraulic oil is press-fitted into the cap side cylinder chamber 333L, and the oil tank 314
to go into.

Next, the rod 62L operates to move the gantry 3
When 0 reaches the angle defined by the set value, the FWD direction tilt end state is entered, and the tilt operation is automatically stopped.
Specifically, the double solenoid valves 321 and 32
The B motion of 2 is completed (404, 405), and the original position is restored. As described above, in such a state, the hydraulic oil between the pipe P3-1 and the pipe P3-2 is shut off, and the hydraulic oil press-fitted into the cap side cylinder chamber 333L is contained, while the pipe P3-. 4 and the pipe P3-5 are also cut off, and the discharge of the hydraulic oil from the head side cylinder chamber 332L is stopped.

After the end of the tilt in the FWD direction, the double solenoid valve 32 is automatically operated after a predetermined time has elapsed.
1 operates in the A direction for a certain period of time (406). As described above, when the double solenoid valve 321 operates in the A direction, it becomes possible to flow the hydraulic oil from the pipe P3-2 to the pipe P3-6. Therefore, the unidirectional hydraulic pump 311 sucks the hydraulic oil from the oil tank 314. The hydraulic oil is press-fitted into the head side cylinder chamber 332L.

As a result, the double-acting hydraulic cylinder 61L
Indicates that both the cap side cylinder chamber 333L and the head side cylinder chamber 332L are in a state in which the hydraulic oil is press-fitted, so that air bubbles due to cavitation or mixed air are compressed, and the cylinder support rigidity of the double-acting hydraulic cylinder 61L is extended. It is possible to increase both the direction and the compression direction.

The double solenoid valve 321 has an A
The operation time of the operation (406) can be arbitrarily adjusted. Further, after the A operation of the double solenoid valve 321 is completed, the operation of the unidirectional hydraulic pump 311 is automatically stopped (407), but the time from the completion of the A operation of the double solenoid valve 321 until the stop of the unidirectional hydraulic pump 311 is completed. Can also be adjusted arbitrarily. Double solenoid valve 321
By the A operation of No. 3, the hydraulic oil continues to be press-fitted into the head side cylinder chamber 332L, but in the hydraulic circuit shown in FIG.
When the pressure in the head side cylinder chamber 332L becomes equal to or higher than a predetermined value, the relief valve 326 is opened, and the working oil pumped from the unidirectional hydraulic pump 311 is supplied to the oil tank 3.
14 to return to the head side cylinder chamber 332L
The pressure inside does not become excessive.

Next, the operation of the double-acting hydraulic cylinder 61L in the BWD direction will be described with reference to the time chart of FIG.

Gantry tilt operation operation screen 5 shown in FIG.
00, normal mode, automatic mode, and BWD
After selecting the direction (501, 503, 506) and inputting a predetermined set value in 508, when the operation start button 510 is turned on, the BWD direction tilt starts, and the double solenoid valve 321 operates in the B direction (408). . As described above, when the double solenoid valve 321 operates in the B direction, the pipes P3-1 and P3-2 communicate with each other. Therefore, when the unidirectional hydraulic pump 311 is stopped, the inside of the cap side cylinder chamber 333L is closed. The hydraulic oil is discharged by the piston 331L being pushed down to the cap side by the weight of the gantry 30 directly connected to the rod 62L.

On the other hand, the double solenoid valve 322 is
Since it operates in the A direction (409), the pipes P3-3, P3
-4 and P3-5 communicate with each other, a part of the hydraulic oil discharged from the cap side cylinder chamber 333L is transferred to the head side cylinder chamber 332L and the rest is held in the oil tank 314.
(The piston 331L operates in the BWD direction due to the weight of the gantry 30 directly connected to the rod 62L, which increases the volume in the head side cylinder chamber 332L.
Because of the negative pressure state, a part of the hydraulic oil discharged from the cap side cylinder chamber 333L is partially discharged from the head side cylinder chamber 332.
Enter L).

As described above, by performing the tilting operation in the BWD direction by the weight of the gantry 30 directly connected to the rod 62L, it is possible to save electric power and to significantly reduce the rise in oil temperature. Further, since a part of the return oil from the cap side cylinder chamber 333L is sent to the head side cylinder chamber 332L, a small amount of hydraulic oil can be effectively used and the oil tank 3
The capacity of 14 can be reduced. Further, the hydraulic pressure in the cap side cylinder chamber 333L is sufficient as long as it can support the load weight, and therefore the hydraulic pressures on the cap side and its path do not rise unnecessarily as in the conventional case. The pressure resistance of hydraulic parts, piping, etc. can be lowered (compact).

Next, the rod 62L operates to move the gantry 3
When 0 reaches the angle defined by the set value, the BWD direction tilt end state is entered, and the tilt operation is automatically stopped.
Specifically, the B operation of the double solenoid valve 321 and the A operation of the double solenoid valve 322L are completed (410, 411), and the original position is restored. As described above, in such a state, the pipe P3-1 and the pipe P3-2 are shut off, and the working oil in the cap side cylinder chamber 333L is contained, while the pipe P3-3 and the pipe P3.
-4 and P3-5 are also cut off from each other, and the working oil discharged from the cap side cylinder chamber 333L does not enter the head side cylinder chamber 332L.

After the tilting state in the BWD direction is completed, the double solenoid valve 32 is automatically operated after a predetermined time has elapsed.
1 operates in the A direction for a certain period of time (412), and the unidirectional hydraulic pump 311 operates (413). As described above, when the double solenoid valve 321 operates in the A direction, the hydraulic oil flows from the pipe P3-2 to the pipe P3-6, so that the hydraulic oil sucked from the oil tank 314 by the unidirectional hydraulic pump 311 is used. Is press-fitted into the head side cylinder chamber 332L.

As a result, since the hydraulic cylinder 61L is in a state in which the hydraulic oil is press-fitted into the head side cylinder chamber 332L, air bubbles due to cavitation or mixed air can be compressed and the cylinder support rigidity of the hydraulic cylinder 61L can be increased. It will be possible.

The double solenoid valve 321 has an A
The operation time of the operation (412) can be arbitrarily adjusted.

As is apparent from the above description, according to the present embodiment, the double-acting hydraulic cylinder is used, and hydraulic control is performed to increase the supporting rigidity of the cylinder while the tilt operation is stopped in both the tension direction and the compression direction. , The vibration generated by rotating the gantry rotating part at high speed is suppressed and cavitation is eliminated, while the tilting operation in the BWD direction is performed by the gantry's own weight, thereby suppressing power consumption, downsizing the tank, and cylinder / hydraulic pressure. Cost reduction can be realized by making parts and the like compact.

(Second Embodiment) In the first embodiment, the case where the double solenoid valve and the unidirectional hydraulic pump are combined has been described, but the present invention is not limited to this. In the present embodiment, a hydraulic circuit that combines a single solenoid valve and a unidirectional hydraulic pump will be described. The hydraulic pump unit 70 (oil tank 314, unidirectional hydraulic pump 311, filter 313, electric motor 31)
2), double-acting hydraulic cylinder 61L (piston 331)
L, head side cylinder chambers 332L, 332R, cap side cylinder chambers 333L, 333R, drain 334),
The rod 62L is the same as that in the first embodiment, and thus the description thereof is omitted. Further, the pressure control valve (relief valve) and the check valve (check valve) provided in the pipe are the same as those in the first embodiment, and therefore the description thereof will be omitted.

In the hydraulic circuit section 82L of FIG. 7, 721
Is a single solenoid valve having two positions of a closing valve and a bidirectional passage valve, and 722 is a closing valve and a two-way passage valve.
Single solenoid valve having a position, 723 is a single solenoid valve having two positions of a check valve (check valve) and a one-way passage valve, and 724 is having two positions of a check valve (check valve) and a two-way passage valve. It has a single solenoid valve.

The single solenoid valve has one coil, and when it is excited (turned on), it operates at a predetermined position, and when it turns off, it returns to its original position. The traveling direction of the hydraulic oil in the pipe is controlled by turning this operation on and off. In the case of FIG. 7, the single solenoid valve 721 is in the OFF state, and shuts off the hydraulic oil between the pipe P7-1 and the pipe P7-2. In this state, the cap side cylinder chamber 33
The hydraulic oil in 3L is in a sealed state, and the rod 6
2L does not move in the BWD direction.

When the single solenoid valve 721 is turned on, the pipe P7-1 and the pipe P7-2 communicate with each other.
If the unidirectional hydraulic pump 311 is in operation, the hydraulic oil sucked up from the oil tank 314 is pressed into the cap side cylinder chamber 333L, while if the unidirectional hydraulic pump 311 is stopped, the cap side cylinder chamber 333L. The hydraulic oil inside is discharged.

Further, in FIG. 7, the single solenoid valve 722 is in the OFF state, and like the single solenoid valve, it shuts off the hydraulic oil between the pipes P7-4 and P7-3. In this state, the hydraulic oil sucked up by the unidirectional hydraulic pump 411 is transferred to the hydraulic cylinder 6
It is not press-fitted into the head side cylinder chamber 332L of 1L. On the other hand, when the single solenoid valve 722 is turned on, the operating oil flows from the pipe P7-3 to the pipe P7-4. Therefore, if the unidirectional hydraulic pump 311 is in operation, the operation sucked from the oil tank 314 is performed. Oil is the head side cylinder chamber 332 of the double-acting hydraulic cylinder 61L.
Pressed into L.

Further, in FIG. 7, the single solenoid valve 723 is in the OFF state. In this state, the hydraulic oil flows from the pipe P7-6 to the pipe P7-5, but the pipe P7-5 to the pipe P7. No hydraulic fluid flows in the -6 direction. Conversely, the single solenoid valve 72
When 3 is turned on, hydraulic oil flows from the pipe P7-5 to the pipe P7-6, but the pipe P7-6 to the pipe P7-5.
No hydraulic fluid flows in the direction of.

Further, in FIG. 7, the single solenoid valve 724 is in an OFF state, and in this state, the hydraulic oil flows from the pipe P7-8 to the pipe P7-7, but the pipe P7-7 to the pipe P7. No hydraulic fluid flows in the -8 direction. Conversely, the single solenoid valve 72
When 4 is turned on, the pipe P7-7 and the pipe P7-8 are in communication with each other.

Next, the operation of the double-acting hydraulic cylinder 61L in the FWD direction will be described with reference to the time chart of FIG. The operation method has been described in the above-described first embodiment with reference to FIG. 5, and will not be repeated here.

In the FWD direction tilt start state, the unidirectional hydraulic pump 311 is operated (801), the single solenoid valve 721 is turned on (802), the pipe P7-1 and the pipe P7-2 are in communication, and The hydraulic oil of is in a bidirectional passing state. On the other hand, simultaneously with this operation, the single solenoid valve 724 is also turned on (803), the pipe P7-7 and the pipe P7-8 are communicated, and the head side cylinder chamber 332L is opened.

As a result, the hydraulic oil sucked up from the oil tank 314 is press-fitted into the cap side cylinder chamber 333L via the single solenoid valve 721 and is rod 62.
L is operated in the FWD direction, and the hydraulic oil in the head side cylinder chamber 332L is changed to the single solenoid valve 7
It is discharged to the oil tank 314 via 24.

When the rod 62L operates and the gantry 30 reaches the angle set by the set value, the tilting operation is automatically stopped in the FWD direction tilt end state. Specifically, the single solenoid valves 721 and 724 are OF
F (803, 804), piping P7-1 and piping P7-2
Is shut off, and the hydraulic oil press-fitted into the cap side cylinder chamber 333L is in a sealed state, while the pipe P7-
7 and the pipe P7-8 are also cut off, and the head side cylinder chamber 33
The discharge of hydraulic oil in 2L stops. At this time, since the unidirectional hydraulic pump 311 is in the ON state, the oil tank 3
The hydraulic oil sucked up from 14 is the relief valve 31.
Return to the oil tank 314 via 5.

After the tilt in the FWD direction is completed, the single solenoid valve 7 is automatically operated after a predetermined time has elapsed.
22 is turned on for a certain period of time (805). When the single solenoid valve 722 is turned on, the pipe P7-3 to the pipe P
Since the hydraulic oil flows to 7-4, the hydraulic oil sucked up by the unidirectional hydraulic pump 311 is transferred to the head side cylinder chamber 33 via the single solenoid valve 722.
It is pressed into 2L. After that, the single solenoid valve 722 is turned off, the working oil press-fitted into the head side cylinder chamber 332L is confined, and the unidirectional hydraulic pump 311 is
Is turned off (806).

As a result, the double-acting hydraulic cylinder 61L
Indicates that the hydraulic oil is press-fitted into both the cap side cylinder chamber 333L and the head side cylinder chamber 332L.
It is possible to increase the support rigidity of the double-acting hydraulic cylinder 61L by compressing bubbles caused by cavitation or mixed air.

The operation of the double-acting hydraulic cylinder 61L in the BWD direction will be described next with reference to the time chart of FIG. The operation method in the BWD direction is also the same as in the above-described first embodiment.

In the tilt start state in the BWD direction, the single solenoid valve 721 is turned on (807) and the pipe P7-1 and the pipe P7-2 communicate with each other, so that the unidirectional hydraulic pump 311 is in the stopped state. The hydraulic oil in the cap side cylinder chamber 333L is discharged by the piston 331L being pushed down to the cap side by the weight of the gantry 30 directly connected to the rod 62L.

On the other hand, since the single solenoid valves 723 and 724 are turned on, the cap side cylinder chamber 33
Part of the hydraulic oil discharged from 3L is discharged to the head side cylinder chamber 332L via the single solenoid valves 723 and 724, and the rest is discharged to the oil tank 314 (by the weight of the gantry 30 directly connected to the rod 62L,
Since the rod 62L operates in the BWD direction, the volume in the head side cylinder chamber 332L increases and a negative pressure state is created. Therefore, a part of the hydraulic oil discharged from the cap side cylinder chamber 333L enters the head side cylinder chamber 332L. enter).

Thus, as in the first embodiment, B
By performing the tilting operation in the WD direction by the weight of the gantry 30 directly connected to the rod 62L, it is possible to save electric power and significantly mitigate the increase in oil temperature. Further, since a part of the return oil from the cap side cylinder chamber 333L is sent to the head side cylinder chamber 332L, a small amount of hydraulic oil can be effectively used and the capacity of the oil tank 314 can be reduced.
Further, since the hydraulic pressure in the cap side cylinder chamber 333 is sufficient as long as it can support the load weight, the hydraulic pressures on the cap side and its path do not unnecessarily rise as in the conventional case. The pressure resistance of hydraulic parts, piping, etc. can be lowered (compact).

When the rod 62L operates and the gantry 30 reaches the angle defined by the set value, the tilting operation is automatically stopped in the BWD direction tilt end state. Specifically, the single solenoid valves 721, 723, 72
4 is turned off, and pipes P7-1, P7-2, P7-8, P
The inflow of hydraulic oil from the cap side cylinder chamber 333L to the head side cylinder chamber 332L via 7-7 is blocked.

After a predetermined time has elapsed after the BWD direction tilt end state, the unidirectional hydraulic pump 311 automatically operates and the single solenoid valve 722 is turned on for a fixed time (813, 814). As a result, the hydraulic fluid sucked up by the unidirectional hydraulic pump 311 is pressed into the head side cylinder chamber 332L of the double-acting hydraulic cylinder 61L via the single solenoid valve 722. After the press-fitting is completed, the single solenoid valve 722 is turned off, and then the unidirectional hydraulic pump 311 is also turned off. As a result, the hydraulic oil press-fitted into the head side cylinder chamber 332L is in a sealed state. As a result, it is possible to compress air bubbles caused by cavitation or mixed air, and increase the support rigidity of the double-acting hydraulic cylinder 61L.

The ON operation time of the single solenoid valve 722 and the ON operation time of the unidirectional hydraulic pump 311 can be arbitrarily adjusted.

As is clear from the above description, even if a single solenoid valve and a unidirectional hydraulic pump are combined, a hydraulic circuit having the same effect as that of the first embodiment can be realized.

(Third Embodiment) In the first and second embodiments, the hydraulic circuit using the unidirectional hydraulic pump has been described, but the present invention is not limited to this. In this embodiment, a hydraulic circuit formed by combining a bidirectional hydraulic pump and a single solenoid valve will be described. Since the single solenoid valve, the check valve (check valve), the double-acting hydraulic cylinder, and the relief valve are the same as those in the first embodiment or the second embodiment, the description thereof will be omitted.

In the hydraulic pump unit 71 of FIG. 9, 911
Is a bidirectional hydraulic pump, and the discharge direction can be switched between the A direction and the B direction by the rotation direction of a motor (not shown). The check valve 913 is a bidirectional hydraulic pump 91.
When 1 is discharging hydraulic oil in the B direction, the hydraulic oil discharged from the left side unit 940L or the right side unit (not shown) to the oil tank 915 and the hydraulic oil sucked up from the filter 914 are prevented from being mixed with each other. It is a valve for Similarly, when the check valve 914 discharges the hydraulic oil in the direction A by the bidirectional hydraulic pump 911, the hydraulic oil discharged from the left side unit 940L or the right side unit (not shown) to the oil tank 915 and the filter This is a valve for preventing mixing with the hydraulic oil sucked up from 914. The hydraulic fluid discharged from the bidirectional hydraulic pump 911 is controlled by a relief valve 916 so that the hydraulic fluid does not exceed a predetermined pressure.
And 917 for pressure control.

Next, the operation of the double-acting hydraulic cylinder 61L in the FWD direction will be described with reference to the time chart of FIG.

In the FWD direction tilt start state, the bidirectional hydraulic pump 911 starts the A operation and (10
01), the single solenoid valve 922 is turned on (1002). As a result, the head side cylinder chamber 332
While L is in an open state, the hydraulic oil sucked from the oil tank 915 is press-fitted into the cap side cylinder chamber 333L of the double-acting hydraulic cylinder 61L.

As a result, the rod 62L operates in the FWD direction, and the hydraulic oil in the head side cylinder chamber 332L is discharged to the oil tank 915 through the single solenoid valve 922.

When the rod 62L operates and the gantry 30 reaches the angle defined by the set value, the tilting operation is automatically stopped in the FWD direction tilt end state. Specifically, the bidirectional hydraulic pump 911 stops and (1
003), the single solenoid valve 922 is turned off (1004). By stopping the bidirectional hydraulic pump 911, the pressurization of the hydraulic oil into the cap side cylinder chamber 333L is stopped, while the single solenoid valve 922 is also turned off, so that the hydraulic oil discharge from the head side cylinder chamber 332L is also stopped. To do. Cap side cylinder chamber 333
A check valve 92 is provided between L and the bidirectional hydraulic pump 911.
3 is present, the hydraulic oil press-fitted into the cap side cylinder chamber 333 is in a sealed state.

After the end of the tilt in the FWD direction, the bidirectional hydraulic pump 911 is automatically set to B
(1004), the hydraulic oil sucked up from the oil tank 915 is pressed into the head side cylinder chamber 332 L via the check valve 926. As a result, in the double-acting hydraulic cylinder 61L, both the cap-side cylinder chamber 333L and the head-side cylinder chamber 332L are in a state in which hydraulic oil is press-fitted, so that air bubbles due to cavitation or mixed air are compressed, and the hydraulic cylinder 61L. It is possible to increase the support rigidity of the.

Then, using the time chart of FIG.
The operation of the double-acting hydraulic cylinder 61L in the BWD direction will be described.

In the BWD direction tilt start state, the single solenoid valve 921 is turned on (1005), and the working oil can flow in the direction from the pipe P9-3 to the pipe P9-4. Therefore, the cap side cylinder chamber 333
The hydraulic oil in L is discharged through the single solenoid valve 921 when the piston 331L is pushed down toward the cap side by the weight of the gantry 30 directly connected to the rod 62L. On the other hand, single solenoid valve 922
Is turned on at the same time (1006), part of the hydraulic oil discharged from the cap side cylinder chamber 333L is discharged to the head side cylinder chamber 332L via the single solenoid valve 922, and the rest is discharged to the oil tank 915. (Due to the weight of the gantry 30 directly connected to the rod 62L,
Since the rod 61L operates in the BWD direction, the volume in the head side cylinder chamber 332L increases, and a negative pressure state is created. Therefore, part of the hydraulic oil discharged from the cap side cylinder chamber 333L enters the head side cylinder chamber 332L. enter).

As described above, similarly to the first and second embodiments, by performing the tilting operation in the BWD direction by the weight of the gantry 30 directly connected to the rod 62L, it is possible to save electric power and significantly increase the oil temperature. Can be relaxed to Further, since a part of the return oil from the cap side cylinder chamber 333L is sent to the head side cylinder chamber 332L, a small amount of hydraulic oil can be effectively used and the capacity of the oil tank 915 can be reduced. Further, the hydraulic pressure in the cap side cylinder chamber 333L is
As long as it can support the load weight, the hydraulic pressure on the cap side and its path will not rise unnecessarily as in the past, and therefore the pressure resistance of the cylinder, hydraulic parts, piping, etc. will be low (compact). You can.

When the rod 62L operates and the gantry 30 reaches the angle defined by the set value, the tilting operation is automatically stopped in the BWD direction tilt end state. Specifically, the single solenoid valves 921 and 922 are OF
F (1007, 1008). As a result, the head side cylinder chamber 332L from the cap side cylinder chamber 333L
The flow of hydraulic oil into the cylinder is stopped, and the hydraulic oil in the cap side cylinder chamber 333L is sealed again.

After the tilt in the BWD direction is completed, the bidirectional hydraulic pump 911 is automatically set to the B
By operating (1009), the hydraulic oil sucked up from the oil tank 915 is press-fitted into the head side cylinder chamber 332L via the check valve 926. This compresses air bubbles due to cavitation or mixed air,
The supporting rigidity of the hydraulic cylinder 61L can be increased.

The operating time of the bidirectional hydraulic pump 911 can be adjusted arbitrarily. In addition, the bidirectional hydraulic pump 91
1 performs B operation, the head side cylinder chamber 332
Although the pressure of the pipe between the bidirectional hydraulic pump 911 increases from L and the head side cylinder chamber 332L, the relief valve 9
When the pressure exceeds the set pressure of 17, the suctioned hydraulic oil is discharged from the relief valve 917 to the oil tank 915, and the pressure is controlled so as not to exceed the predetermined pressure.

As is clear from the above description, a hydraulic circuit having the same effects as those of the first and second embodiments can be realized by combining the single solenoid valve and the bidirectional hydraulic pump.

(Fourth Embodiment) The first to third embodiments described above have dealt with the case of normal operation in the X-ray CT apparatus. That is, in the FWD direction, hydraulic oil is pressed into the cap side cylinder chamber 333L to operate,
By connecting the cap side cylinder chamber 333L and the head side cylinder chamber 332L in the WD direction, the rod 62L
It was operated by the weight of the gantry 30 directly connected to.

However, for example, when the cover on the back surface of the gantry 30 is removed during maintenance, the weight of the gantry 30 is not sufficient. Therefore, in the case of a conventional single-acting cylinder, the head side cylinder chamber is opened. Sometimes did not work in the BWD direction.

On the other hand, in the case of the hydraulic system of the present invention, a double-acting hydraulic cylinder is used, and hydraulic oil is directly sent to the head side cylinder chamber 332L by a double-acting hydraulic pump. Since it has a hydraulic circuit configuration capable of operating, it is possible to press working oil into the head side cylinder chamber, and it is possible to operate in the BWD direction even when the own weight is not sufficient. In the present embodiment, a preferred example of hydraulic control during maintenance when the hydraulic system of the present invention is used (specifically, the hydraulic system described in the third embodiment) will be described.

FIG. 11 is a time chart showing the BWD direction operation at the time of maintenance using the hydraulic circuit (FIG. 9) described in the third embodiment (in FIG. 11, the tilt operation in the normal mode is , The description is omitted because it is the same as FIG. 10, and only the case during maintenance is described). Whether or not the maintenance is being performed is determined by the operation mode (FIG. 5) of the X-ray CT apparatus, and when the operation mode is the service mode, it is recognized that the maintenance is being performed. The conditions for shifting to the service mode may be determined automatically based on, for example, a signal from a sensor that detects the presence or absence of a cover on the back of the gantry, or may be automatically shifted. From the screen 500, the process may be performed when the operator manually turns on the service mode.

When the X-ray CT apparatus is in the service mode, "BWD direction" (506) is selected, a predetermined set value is input to 508, and the operation start button 510 is turned on. Operates in the B direction (1101), and the single solenoid valve 921 is turned on (1102). As a result, the hydraulic oil sucked up from the oil tank 915 is transferred to the head side cylinder chamber 332.
It is press-fitted in L and the cap side cylinder chamber 333L
Is opened, the hydraulic oil in the cap side cylinder chamber 333L is discharged to the oil tank 915. Therefore, the double-acting hydraulic cylinder 61L can be operated in the BWD direction even if the gantry 30 to which the rod 62L is directly connected does not have sufficient self-weight.

Further, the rod 62L operates to move the gantry 3
When 0 reaches the angle defined by the set value, the BWD direction tilt end state is entered, and the tilt operation is automatically stopped.
Specifically, the bidirectional hydraulic pump 911 stops operating in the B direction (1103), the single solenoid valve 921 turns OFF (1104), and the operation in the BWD direction stops.

As described above, the hydraulic circuit shown in FIG. 9 operates by operating the hydraulic cylinder in the BWD direction by the weight of the gantry 30 directly connected to the rod 62L, or by operating the hydraulic oil by press-fitting it into the head side cylinder chamber 332L. Since it has a characteristic configuration that can be performed, the service mode as described above can also be supported. In addition, FW
The tilt operation in the D direction is the same as in the service mode.

(Fifth Embodiment) In the first to fourth embodiments described above, the tilt angle is set by the operator (508 in FIG. 5), and the operation start button 510 is turned on to set a predetermined tilt angle. Up to when it operates automatically.

In this embodiment, the case where the operator manually performs the tilting operation will be described. The manual tilting operation continues the tilting operation while pressing the local tilt button (FIG. 6) on the gantry 30, and stops the tilting operation when the pressing is released. That is, the operator looks at the tilt angle of the actual gantry 30 and
The actual operation is F to instruct WD operation / BWD operation.
The WD direction tilt operation switch 601 or the BWD direction tilt operation switch 602 is turned on and off a plurality of times to set a desired angle. For this reason, the X-ray CT apparatus needs to recognize that the tilt operation is completed when performing the press-fitting operation of the hydraulic oil into the head side cylinder chamber 332L.

In FIG. 12, the operation mode of the tilt operation is the manual mode, and the control panel 6 on the gantry 30 is used.
FIG. 10 is a diagram showing a time chart when a tilt operation is performed by setting 00.

When the operator presses the FWD direction tilt operation switch 601, the bidirectional hydraulic pump 911 starts A operation (1201), the single solenoid valve 922 is turned on (1202), and the hydraulic oil is supplied to the cap side cylinder chamber 333L. Is press-fitted, and the head side cylinder chamber 332L is opened. Bidirectional hydraulic pump 911
The A operation of is continued while the operator is pressing the FWD direction tilt operation switch 601. When the FWD direction tilt operation switch 601 is turned off, the A operation is also stopped (1203). Similarly, a single solenoid valve 92
2 is the operator's FWD direction tilt operation switch 60
The ON state continues while 1 is pressed, and when the FWD direction tilt operation switch 601 is turned OFF, it is turned OFF (1204).

Manual operation allows the gantry 30 to move to the desired F
After reaching the tilt angle in the WD direction, the operator gives an instruction to start scanning from the screen on the operation console (not shown in FIG. 5). The tilt control unit 60A of the gantry 30 receives the scan start signal to recognize that the tilt operation by the operator is completed (120).
6). Note that the tilt operation is completed until the next tilt operation is performed (that is, the BWD direction tilt operation switch 6
02 or until the FWD direction tilt operation switch 601 is pressed).

When the tilt control section 60A recognizes the completion of the tilt operation (1206), the bidirectional hydraulic pump 911 is turned on.
As a result, the hydraulic oil is pressed into the head side cylinder chamber 332L (1205).

Similarly, when the operator presses the BWD direction tilt operation switch 602, it is recognized that the tilt operation is restarted (1209). Further, the single solenoid valves 921 and 922 are turned on (1207 and 120).
8), due to the weight of the gantry 30 directly connected to the rod 62L, the piston 331L operates in the BWD direction,
The hydraulic oil in the cap side cylinder chamber 333L flows into the head side cylinder chamber 332L. The ON state of the single solenoid valves 921 and 922 continues while the BWD direction tilt operation switch 602 is pressed (121
0, 1211).

The gantry 30 is set to the desired B by manual operation.
After reaching the tilt angle in the WD direction, the operator gives an instruction to start scanning from the screen on the operation console. The tilt control unit of the gantry 30 receives the scan start signal to recognize that the tilt operation by the operator is completed (1213).

When the tilt control section 60A recognizes the completion of the tilt operation, the bidirectional hydraulic pump 911 performs the B operation (12
12), hydraulic oil is press-fitted into the head side cylinder chamber 332L.

As described above, even during the manual tilting operation, the operation oil is automatically supplied to the head side cylinder chamber 332L by taking in the signal (in this embodiment, the scan start signal) indicating that the tilting operation is completed. It is possible to press-fit and increase the support rigidity of the cylinder of the hydraulic cylinder 61L.

(Sixth Embodiment) It is also possible to use the fourth embodiment and the fifth embodiment in combination.

FIG. 13 is a diagram showing a time chart in the case where the tilt operation in the manual mode in the normal mode (FWD direction, BWD direction) is performed, and then the tilt operation in the BWD direction is performed in the automatic mode in the service mode. is there. Note that the individual operations of the bidirectional hydraulic pump 911 and the single solenoids 921 and 922 have already been described in the above fourth and fifth embodiments, and a description thereof will be omitted.

(Seventh Embodiment) In the second embodiment, only the left side unit (340L) is shown, and the same applies to the right side unit. However, the single solenoid valve used for the left side unit is described. It is also possible to reduce the number of single solenoid valves by sharing the single solenoid valve used for the right unit.

FIG. 14 is a diagram showing a hydraulic system according to the seventh embodiment of the present invention. In the hydraulic system according to the second embodiment, four single solenoid valves (721 to 724) are used as the left side unit and the right side unit has the same structure. Therefore, the left side unit and the right side unit have eight single solenoid valves. Although required, the hydraulic system according to the present embodiment has six single solenoid valves (1
421 to 1426).

That is, the cap side cylinder chamber 333L
Further, such a simple hydraulic circuit is realized by sharing the single solenoid (1421, 1424) for press-fitting the hydraulic oil into the head side cylinder chamber 332L.

FIG. 15 is a diagram showing a time chart of the FWD direction operation and the BWD direction operation when the hydraulic circuit shown in FIG. 14 is used.

In the FWD direction tilt start state, the electric motor 1412 of the hydraulic pump portion 72 operates, the unidirectional hydraulic pump 1411 operates (1501), and the single solenoid valves 1421, 1425, 1426.
Is turned on (1502, 1503), the head side cylinders 332L, 332R are opened, while the hydraulic oil is press-fitted into the cap side cylinder chambers 333L, 333R.

As a result, the hydraulic oil sucked up from the oil tank 1414 through the filter 1413 is press-fitted into the cap side cylinder chambers 333L and 333R through the single solenoid valve 1421, and the rods 62L and 62R.
Is operated in the FWD direction, and the hydraulic oil in the head side cylinder chambers 333L, 333R is discharged via the single solenoid valves 1425, 1426.

When the rods 61L and 62R operate and the gantry 30 reaches the angle determined by the set value, the tilting operation is automatically stopped in the FWD direction tilt end state. Specifically, the single solenoid valve 1421 is O
FF (1504), cap side cylinder chamber 333L,
The hydraulic oil press-fitted into the 333R is in a sealed state, while the single solenoid valves 1425, 1426
Turns off (1505) and the head side cylinder chamber 332
The discharge of hydraulic oil in L and 332R stops. At this time, since the unidirectional hydraulic pump 1411 is in the ON state,
The hydraulic oil sucked from the oil tank 1414 returns to the oil tank 1414 via the relief valve 1427.

After the tilt in the FWD direction is completed, the single solenoid valve 1 is automatically operated after a predetermined time has elapsed.
424 is turned on for a fixed time (1506). When the single solenoid valve 1424 is turned on, the hydraulic oil sucked up by the unidirectional hydraulic pump 1411 is transferred through the single solenoid valve 1424 to the head side cylinder chamber 33.
Pressed into 2L and 332R. After that, the single solenoid 1424 is turned off, and the head side cylinder chamber 332
The hydraulic oil press-fitted into L and 332R is enclosed, and the unidirectional hydraulic pump 1411 is turned off (1507).

As a result, the double-acting hydraulic cylinder 61L,
In the case of 61R, the cap side cylinder chambers 333L and 333R are in a state in which the hydraulic oil is press-fitted together with the head side cylinder chambers 332L and 332R. It is possible to increase the support rigidity of the.

Then, using the time chart of FIG.
The operation of the double-acting hydraulic cylinders 61L and 61R in the BWD direction will be described.

In the BWD direction tilt start state, the single solenoid valves 1422 and 1423 are turned on (1
508), when the unidirectional hydraulic pump 1411 is in a stopped state, the working oil in the cap side cylinder chambers 333L, 333R is directly connected to the rods 62L and 62R in the gantry 3.
It is discharged by its own weight of 0.

On the other hand, single solenoid valve 1425
And 1426 are turned on, the operating oil discharged from the cap side cylinder chambers 333L, 333R is partially transferred to the head side cylinder chambers 332L, 332R via the single solenoid valves 1425 and 1426, and the rest is transferred to the oil tank 1414. Ejected (rods 62L, 62
Since the rods 62L and 62R operate in the BWD direction by the weight of the gantry 30 directly connected to R, the volume in the head side cylinder chambers 332L and 332R increases, and a negative pressure state occurs, so the cap side cylinder chambers 333L and 333R. A part of the hydraulic oil discharged from the head side cylinder chamber 332
L, entering 332R).

Thus, as in the first embodiment, B
By performing the tilting operation in the WD direction by the weight of the gantry 30 directly connected to the rods 62L and 62R, it is possible to save electric power and significantly mitigate the increase in oil temperature. Also,
Since a part of the return oil from the cap side cylinder chambers 333L, 333R is sent to the head side cylinder chambers 332L, 332R, a small amount of hydraulic oil can be effectively used and the capacity of the oil tank 1414 can be reduced. Further, since the hydraulic pressures in the cap side cylinder chambers 333L, 333R are sufficient as long as they can support the load weight, the hydraulic pressures on the cap side and its path do not unnecessarily rise unlike the conventional case.
Therefore, the pressure resistance of the cylinder, hydraulic parts, piping, etc. can be lowered (made compact).

When the rods 62L and 62R operate and the gantry 30 reaches the angle defined by the set value, the BWD direction tilt end state is entered, and the tilt operation is automatically stopped. Specifically, the single solenoid valve 1422,
1423 is turned off (1508), the cap side cylinder chambers 333L and 333R to the head side cylinder chamber 332L.
Inflow of hydraulic oil to 332R is blocked.

After a predetermined time has elapsed after the BWD direction tilt end state, the unidirectional hydraulic pump 1411 automatically operates and the single solenoid valve 1424 is turned on. As a result, the hydraulic oil sucked up by the unidirectional hydraulic pump 1411 is the same as the single solenoid valve 1
Via 424, double-acting hydraulic cylinders 61R, 61L
Are press-fitted into the head side cylinder chambers 332R, 332L. After completion of press fitting, single solenoid valve 1424
Turns off, and then the unidirectional hydraulic pump 1411 also turns off.
F As a result, the head side cylinder chambers 332L, 33L
The hydraulic oil press-fitted into 2R is in a sealed state.
As a result, air bubbles caused by cavitation or mixed air are compressed, and double-acting hydraulic cylinders 61L and 61R are compressed.
It is possible to increase the support rigidity of the.

(Eighth Embodiment) It is also possible to use the fourth embodiment and the seventh embodiment in combination.

FIG. 16 shows a BWD during maintenance using the hydraulic circuit (FIG. 14) described in the seventh embodiment.
15 is a time chart showing a directional operation (FIG. 14).
For the tilt operation in the normal mode,
The description is omitted because it is the same as in FIG. 15, and only the case during maintenance is described). Whether or not the maintenance is being performed is determined by the operation mode (FIG. 5) of the X-ray CT apparatus, as in the fourth embodiment, and when the operation mode is the service mode, it is recognized that the maintenance is being performed. The conditions for shifting to the service mode may be determined automatically based on, for example, a signal from a sensor that detects the presence or absence of a cover on the back of the gantry, or may be automatically shifted. From the screen 500, the process may be performed when the operator manually turns on the service mode.

When the X-ray CT apparatus is in the service mode, "BWD direction" (506) is selected, a predetermined set value is input to 508, and the operation start button 510 is turned on. Is operated (1601), single solenoid valves 1422, 1
423 is turned on (1602). As a result, the hydraulic oil sucked up from the oil tank 1414 is pressed into the head side cylinder chambers 332L, 332R and the cap side cylinder chambers 333L, 333R are opened, so that the operation inside the cap side cylinder chambers 333L, 333R is performed. Oil is
It is discharged to the oil tank 1414. Therefore, the rod 61
Even if the gantry 30 directly connected to the L and 62R does not have sufficient weight, the double-acting hydraulic cylinders 61L and 61R can be operated in the BWD direction.

When the rods 62L and 62R operate and the gantry 30 reaches the angle defined by the set value, the BW
The tilt in the D direction is completed, and the tilt operation automatically stops. Specifically, the operation of the unidirectional hydraulic pump 1411 is stopped (1604), the single solenoid valves 1422 and 1423 are turned off (1605), and the BW is set.
The operation in the D direction stops.

As described above, in the hydraulic circuit shown in FIG. 14, the hydraulic cylinder is operated in the BWD direction by the weight of the gantry 30 directly connected to the rods 62L and 62R, and the hydraulic oil is pressed into the head side cylinder chambers 332L and 332R. Since it has a characteristic configuration that can be operated by doing so, it is possible to support the service mode as described above. Regarding the tilting operation in the FWD direction,
Operates in the same way as service mode.

[0139]

As described above, according to the present invention,
It is possible to provide a hydraulic system having a high cylinder support rigidity against a force in an arbitrary direction at a small scale and at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of an X-ray CT apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a mechanism portion of a gantry device of the X-ray CT apparatus according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram of the hydraulic system according to the first embodiment of the present invention, showing a hydraulic circuit when a double solenoid valve and a unidirectional hydraulic pump are combined.

FIG. 4 is a diagram showing an operation in the hydraulic system of the X-ray CT apparatus according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of a gantry tilt operation operation screen of the X-ray CT apparatus according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a local tilt button on the gantry device of the X-ray CT apparatus according to the first embodiment of the present invention.

FIG. 7 is a circuit diagram of a hydraulic system according to a second embodiment of the present invention, showing a hydraulic circuit when a single solenoid valve and a unidirectional hydraulic pump are combined.

FIG. 8 is a diagram showing an operation of the hydraulic system of the X-ray CT apparatus according to the second embodiment of the present invention.

FIG. 9 is a circuit diagram of a hydraulic system according to a third embodiment of the present invention, showing a hydraulic circuit when a single solenoid valve and a bidirectional hydraulic pump are combined.

FIG. 10 is a diagram showing an operation in a hydraulic system of the X-ray CT apparatus according to the third embodiment of the present invention.

FIG. 11 is a diagram showing an operation in the hydraulic system of the X-ray CT apparatus according to the fourth embodiment of the present invention.

FIG. 12 is a diagram showing an operation in a hydraulic system of the X-ray CT apparatus according to the fifth embodiment of the present invention.

FIG. 13 is a diagram showing an operation in a hydraulic system of the X-ray CT apparatus according to the sixth embodiment of the present invention.

FIG. 14 is a diagram showing a hydraulic system according to a seventh embodiment of the present invention.

FIG. 15 is a view showing an operation of the hydraulic system of the X-ray CT apparatus according to the seventh embodiment of the present invention.

FIG. 16 is a diagram showing an operation of the hydraulic system of the X-ray CT apparatus according to the eighth embodiment of the present invention.

FIG. 17 is a side view of an imaging table and a gantry device of a conventional X-ray CT apparatus.

FIG. 18 is a diagram showing a circuit of a hydraulic system for tilting a gantry of a conventional X-ray CT apparatus.

Continued front page    (72) Inventor Akira Izumihara             127, 4-7 Asahigaoka, Hino City, Tokyo             GE Yokogawa Medical System Co., Ltd.             Within (72) Inventor Masashi Maida             127, 4-7 Asahigaoka, Hino City, Tokyo             GE Yokogawa Medical System Co., Ltd.             Within F-term (reference) 3H089 AA61 BB27 CC01 DA02 DB33                       DB44 DB48 EE31 JJ20                 4C093 AA22 BA03 CA16 CA32 EC47

Claims (44)

[Claims] 1. A rod, which is directly connected to the piston of a double-acting cylinder in which hydraulic pressure acts in both directions of a cap side and a head side with a piston as a boundary, supports a required load weight, and opposes the load weight by the rod. Top with load weight /
In a hydraulic system driven in a downward direction, a first hydraulic path that guides pressure oil from a hydraulic pump to the cap side via first and second switching valves, and oil pushed out from the cap side by load weight A second hydraulic path for returning to the reservoir tank side via the second switching valve and the third switching valve, and a third hydraulic line connecting the third switching valve and the head side.
And a fourth hydraulic path for guiding the pressure oil from the hydraulic pump to the head side through the second switching valve. 2. The first switching valve is a check valve that guides pressure oil from the hydraulic pump to the cap side and reversely stops return oil from the cap side. Hydraulic system described in. 3. The second switching valve includes a stop valve for closing the first hydraulic path and the second hydraulic path, a bidirectional passage valve for bidirectional passage, and a pressure from the hydraulic pump. The hydraulic system according to claim 1, wherein the hydraulic system is a solenoid valve capable of switching between a one-way passage valve that guides oil to the head side. 4. The third switching valve includes a closing valve that closes the second hydraulic path and the third hydraulic path, guides oil pushed out from the cap side by the load weight to a reservoir tank, The hydraulic system according to claim 1, wherein the hydraulic system is a solenoid valve capable of switching between a path leading to the head side and a one-way passage valve guiding oil discharged from the head side to the reservoir tank. 5. The control method for a hydraulic system according to claim 1, wherein the hydraulic pressure is injected into the cap side via the first hydraulic path, and at the same time, the third switching is performed. A first step of driving the rod by a desired amount by guiding the oil discharged from the head side to the reservoir tank with the valve opened, and a desired amount of the rod by the first step After that, the third switching valve is closed to stop the discharge of oil from the head side, and at the same time, the second switching valve is opened to guide the pressure oil from the hydraulic pump to the head side. And a second step, which is a method for controlling a hydraulic system. 6. A method for controlling a hydraulic system according to claim 1, wherein the second switching valve is opened to push out the oil on the cap side by the load weight. The first step of driving the rod by a desired amount by opening the third switching valve and injecting the extruded oil to the head side, and the rod is desired by the first step. After being driven for a certain amount, the third switching valve is closed to stop the injection of the oil pushed out from the cap side to the head side, and at the same time, the second switching valve is opened to open the hydraulic pressure. A second step of guiding pressure oil from a pump to the head side, the method for controlling a hydraulic system. 7. The method according to claim 5, wherein the second step is carried out when a predetermined signal is received after the rod is driven by a desired amount in the first step.
A method for controlling a hydraulic system described in. 8. A rod directly connected to the piston of a double-acting cylinder in which hydraulic pressure acts in both the cap side and the head side with the piston as a boundary supports a required load weight, and the rod opposes the load weight. Top with load weight /
In a hydraulic system driven in a downward direction, a first hydraulic path that guides pressure oil from a hydraulic pump to the cap side via first and second switching valves, and oil pushed out from the cap side by the load weight. Via the second switching valve and the third switching valve to the reservoir tank side, and between the third switching valve and the head side via the fourth switching valve. A hydraulic system comprising: a third hydraulic path to be connected; and a fourth hydraulic path that guides the pressure oil from the hydraulic pump to the head side via a fifth switching valve. 9. The first switching valve is a check valve that guides pressure oil from the hydraulic pump to the cap side and reversely stops return oil from the cap side. 8. The hydraulic system according to item 8. 10. The second switching valve is a solenoid valve capable of switching between a closing valve that closes the first hydraulic path and the second hydraulic path and a bidirectional passage valve that allows bidirectional passage. 9. The hydraulic system of claim 8, wherein the hydraulic system is. 11. The third switching valve can switch between a closing valve that closes the second hydraulic path and a one-way passage valve that guides oil pushed out from the cap side by the load weight to a reservoir tank. 9. The hydraulic system according to claim 8, wherein the hydraulic system is a solenoid valve. 12. The fourth switching valve is an electromagnetic valve capable of switching between a check valve for reversely stopping the return oil from the head side and a bidirectional passage valve for passing the oil in both directions. The hydraulic system according to claim 8. 13. The solenoid valve capable of switching between a closing valve that closes the fourth hydraulic path and a one-way passage valve that guides the pressure oil from the hydraulic pump to the head side. 9. The hydraulic system according to claim 8, wherein 14. A method for controlling a hydraulic system according to claim 8, wherein the hydraulic pressure is injected into the cap side via the first hydraulic path, and at the same time, the fourth switching is performed. A first step of driving the rod by a desired amount by guiding the oil discharged from the head side to the reservoir tank with the valve opened, and a desired amount of the rod by the first step After that, the fourth switching valve is closed to stop the discharge of oil from the head side, and at the same time, the fifth switching valve is opened to guide the pressure oil from the hydraulic pump to the head side. And a second step, which is a method for controlling a hydraulic system. 15. A hydraulic system control method for controlling a hydraulic system according to claim 8, wherein the second switching valve is opened and the oil on the cap side is pushed out by the load weight. By the first step of driving the rod by a desired amount by opening the third and fourth switching valves and injecting the pushed out oil to the head side, After driving the rod by a desired amount, the second to fourth switching valves are closed to stop the injection of the oil extruded from the cap side to the head side, and at the same time the fifth switching mode is set. A second step of opening the valve to guide the pressure oil from the hydraulic pump to the head side. 16. The method according to claim 14, wherein the second step is carried out when a predetermined signal is received after the rod is driven by a desired amount in the first step. Hydraulic system control method. 17. A rod directly connected to the piston of a double-acting cylinder in which hydraulic pressure acts in both the cap side and the head side with the piston as a boundary supports a required load weight, and the rod opposes the load weight or In a hydraulic system that is driven upward / downward with load weight, a hydraulic pump capable of changing the direction of oil discharge, and pressure oil from the hydraulic pump is guided to the cap side via a first switching valve. A first hydraulic path; a second hydraulic path that returns the oil pushed out from the cap side by the load weight to the reservoir tank side via a second switching valve; the second switching valve and the head side; A third hydraulic path that connects the two via a third switching valve, and a fourth hydraulic path that guides pressure oil from the hydraulic pump to the head side via a fourth switching valve. Special Hydraulic system that. 18. The check valve, wherein the first switching valve guides pressure oil from the hydraulic pump to the cap side and reversely stops return oil from the cap side. 17. The hydraulic system according to item 17. 19. The second switching valve can switch between a check valve for reversely stopping the pressure oil in the first hydraulic path and a one-way passage valve for guiding the oil pushed out from the cap side to the reservoir tank side. 18. The hydraulic system according to claim 17, which is a simple solenoid valve. 20. The third switching valve is a solenoid valve capable of switching between a check valve for non-returning pressure oil in a third hydraulic path and a one-way passage valve for passing in the non-return direction. The hydraulic system according to claim 17, wherein: 21. The fourth switching valve is a check valve that guides pressure oil from the hydraulic pump to the head side and reversely stops return oil from the cap side. 17. The hydraulic system according to item 17. 22. A hydraulic system control method for controlling a hydraulic system according to claim 17, wherein oil is discharged from the hydraulic pump in a predetermined direction,
At the same time as injecting pressure oil into the cap side through the first hydraulic path, the third switching valve is opened and the oil discharged from the head side is guided to the reservoir tank. And driving the rod by the desired amount in the first step, and then closing the third switching valve to stop the discharge of oil from the head side at the same time. And a second step of injecting pressure oil to the head side through the fourth hydraulic path by discharging oil from the hydraulic pump in a direction opposite to the predetermined direction. Hydraulic system control method. 23. A method for controlling a hydraulic system according to claim 17, wherein the second switching valve is opened to push out the oil on the cap side by the load weight, The first step of driving the rod by a desired amount by opening the third switching valve and injecting the extruded oil to the head side, and the rod is desired by the first step. After the amount is driven, the second and third switching valves are closed to stop the injection of the oil pushed out from the cap side to the head side, and at the same time, the hydraulic pump is driven to A second step of injecting pressure oil to the head side through a fourth hydraulic path, the control method of the hydraulic system. 24. The method according to claim 22 or 23, wherein the second step is performed when a predetermined signal is received after the rod is driven by a desired amount in the first step. Hydraulic system control method. 25. The hydraulic system according to claim 17, which is a control method of the hydraulic system when the load weight supported by the rod is less than or equal to a predetermined amount, wherein the second switching valve is opened. At the same time, the method for controlling a hydraulic system is characterized by comprising the step of injecting pressure oil to the head side through the fourth hydraulic path by driving the hydraulic pump. 26. A rod directly connected to the piston of two first and second double-acting cylinders, on which hydraulic pressure acts in both cap-side and head-side directions with respect to the piston, supports a required load weight, and the rod. In an upward / downward direction in which the valve is driven against the load weight or together with the load weight, pressure oil from a hydraulic pump is passed through first and second switching valves, and the cap of the first double-acting cylinder is A first hydraulic path leading to the side, and a second hydraulic path guiding pressure oil from the hydraulic pump to the cap side of the second double-acting cylinder via the first and third switching valves, A third hydraulic path for returning the oil pushed out from the cap side of the first double-acting cylinder to the reservoir tank side via the fourth switching valve by the load weight, and the second double-action by the load weight. Shirin Between the fourth switching valve and the head side of the first double-acting cylinder, the fourth hydraulic path for returning the oil pushed out from the cap side to the reservoir tank side via the fifth switching valve Is connected via a sixth switching valve, and the fifth switching valve and the head side of the second double-acting cylinder are connected via a seventh switching valve. A sixth hydraulic path, and a seventh hydraulic fluid from the hydraulic pump is guided to the head side of the first double-acting cylinder via the eighth and ninth switching valves.
And an eighth hydraulic path for guiding the pressure oil from the hydraulic pump to the head side of the second double-acting cylinder via the eighth and tenth switching valves. Hydraulic system. 27. The first switching valve guides pressure oil from the hydraulic pump to a cap side of the first and second double-acting cylinders, and a closing valve that closes the first hydraulic path. 27. The hydraulic system according to claim 26, which is an electromagnetic valve capable of switching between a one-way passage valve and the solenoid valve. 28. The second switching valve is a check valve that guides pressure oil from the hydraulic pump to a cap side of the first double-acting cylinder and reversely stops return oil from the cap side. 27. The hydraulic system according to claim 26, wherein: 29. The third switching valve is a check valve that guides pressure oil from the hydraulic pump to a cap side of the second double-acting cylinder and reversely stops return oil from the cap side. 27. The hydraulic system according to claim 26, wherein: 30. The closing valve for closing the third hydraulic path, and the fourth switching valve for guiding oil pushed out from the cap side of the first double-acting cylinder to the reservoir tank by the load weight. 27. The hydraulic system according to claim 26, which is an electromagnetic valve capable of switching between a directional valve and a directional valve. 31. The closing valve for closing the fourth hydraulic path, and the fifth switching valve for guiding the oil pushed by the load weight from the cap side of the second double-acting cylinder to a reservoir tank. 27. The hydraulic system according to claim 26, which is an electromagnetic valve capable of switching between a directional valve and a directional valve. 32. The sixth switching valve is an electromagnetic switchable switch between a check valve for reversely stopping return oil from the head side of the first double-acting cylinder and a two-way passage valve for two-way passage. 27. The hydraulic system of claim 26, which is a valve. 33. The seventh switching valve is an electromagnetic switchable switch between a check valve for reversely stopping return oil from the head side of the second double-acting cylinder and a bidirectional passage valve for bidirectional passage. 27. The hydraulic system of claim 26, which is a valve. 34. The eighth switching valve guides pressure oil from the hydraulic pump to a head side of the first and second double-acting cylinders, and a closing valve that closes the seventh hydraulic path. 27. The hydraulic system according to claim 26, which is an electromagnetic valve capable of switching between a one-way passage valve and the solenoid valve. 35. The ninth switching valve is a check valve that guides pressure oil from the hydraulic pump to a head side of the first double-acting cylinder and reversely stops return oil from the head side. 27. The hydraulic system according to claim 26, wherein: 36. The tenth switching valve is a check valve that guides pressure oil from the hydraulic pump to a head side of the second double-acting cylinder and reversely stops return oil from the head side. 27. The hydraulic system according to claim 26, wherein: 37. A hydraulic system control method for controlling a hydraulic system according to claim 26, wherein pressure oil is injected into the cap side via the first and second hydraulic paths, and at the same time. A first step of driving the rods of the first and second double-acting cylinders by a desired amount by opening the sixth and seventh switching valves and guiding the oil discharged from the head side to the reservoir tank. After driving the rod by a desired amount in the first step, the sixth and seventh switching valves are closed to stop oil discharge from the head side, and at the same time the eighth switching is performed. A second step of opening the valve to guide the pressure oil from the hydraulic pump to the head side. 38. A hydraulic system control method for controlling a hydraulic system according to claim 26, wherein the fourth and fifth switching valves are opened to push out the oil on the cap side by the load weight. At the same time, the first step of driving the rod by a desired amount by opening the sixth and seventh switching valves and injecting the extruded oil into the head side, and the first step. After the rod is driven by a desired amount in the step, the fourth to seventh switching valves are closed to stop the injection of the oil extruded from the cap side to the head side, and at the same time, the eighth And a second step of opening the switching valve to open the pressure oil from the hydraulic pump to the head side. 39. The method according to claim 37 or 38, wherein the second step is performed when a predetermined signal is received after the rod is driven by a desired amount in the first step. Hydraulic system control method. 40. The hydraulic system according to claim 26, which is a method of controlling the hydraulic system when the load weight supported by the rod is equal to or less than a predetermined amount, wherein the fourth and fifth switching valves are provided. At the same time as opening
A method for controlling a hydraulic system, comprising the step of injecting pressure oil to the head side by opening the eighth switching valve. 41. An X-ray CT apparatus using the hydraulic system according to claim 1 as a tilt mechanism of a gantry. 42. An X-ray CT apparatus, wherein the hydraulic system according to claim 8 is used as a tilt mechanism of a gantry. 43. A hydraulic system according to claim 17,
X characterized by being used as a gantry tilt mechanism
X-ray CT equipment. 44. A hydraulic system according to claim 26,
X characterized by being used as a gantry tilt mechanism
X-ray CT equipment.