JP3477491B2 - Hydraulic device for deck lifting - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic system for raising and lowering a deck of an automobile transportation container. Also, the present invention relates to a technique for improving the amount of hydraulic oil in the oil tank of the external hydraulic source so as not to increase or decrease.

[0002]

2. Description of the Related Art A container equipped with a plurality of automobiles is
An automobile transportation system for transporting a trailer and a freight car together is disclosed in JP-A-7-2099 and JP-A-6-1000.
No. 77, etc.

An example of a vehicle-mounted container used in such a vehicle transportation system is shown in FIGS.
The container 3 mounted on the bed 2 of the trailer 1 has a pair of front and rear upper decks 5, which are respectively moved up and down by four sets of deck lifting hydraulic cylinders 4. Then, the hydraulic cylinder 4 expands and contracts by the hydraulic pressure supplied from the external hydraulic power source 7 driven by the engine of the tractor 6 to the container 3 side via the pipeline 7a and the joint 7b provided in the container 3. It is like this.

When loading a car 8 into the container 3,
As shown in FIG. 3, while lowering the pair of upper decks 5, the road board 9 provided behind the luggage carrier 2 is grounded. After mounting the automobile 8 on the pair of upper decks 5,
The upper deck 5 by extending the hydraulic cylinder 4 for raising and lowering the deck
Raise. Next, as shown in FIG. 4, the automobile 8 is mounted on the lower deck 10 and the loading of the automobile 8 into the container 3 is completed. The container 3 that has been loaded with the automobiles 8 is transported to the freight terminal of the railroad by the trailer 1 as shown in FIG. Then, the container 3 arriving at the cargo terminal is disconnected from the external hydraulic power source 7 by removing the conduit 7a from the joint 7b, and then the container 2 of the trailer 1 is loaded by a forklift (not shown) as shown in FIG. It is lifted from and transferred to a freight car.

[0005]

By the way, when the upper deck 5 of the container 3 is raised as described above, a predetermined amount of the external hydraulic power source 7 installed in the tractor 6 is placed in the hydraulic cylinder 4 for raising and lowering the deck. Pressure oil must be fed to extend the deck lifting hydraulic cylinder 4. And
The container 3 is transferred to the freight car while the upper deck 5 is raised, that is, the deck lifting hydraulic cylinder 4 is extended. As a result, the pressure oil sent from the external hydraulic source 7 into the deck lifting hydraulic cylinder 4 does not return to the oil tank of the external hydraulic source 7. Therefore, in the trailer 1 in which loading of vehicles into the container 3 and transportation to the freight terminal are repeated, the amount of hydraulic oil in the oil tank of the external hydraulic power source 7 decreases gradually. On the contrary, in the trailer 1 which repeats the work of transporting the container 3 transferred from the freight car and lowering the automobile 8, the hydraulic oil discharged from the deck lifting hydraulic cylinder 4 every time the upper deck 5 is lowered. Is received, the hydraulic oil in the oil tank of the external hydraulic power source 7 increases more and more.

Therefore, as shown in FIG. 6, the container 3
Hydraulic device 11 for raising and lowering the upper deck 5
The oil tank 12 is added to the container 3 side of the above, and the oil tank 12 and the external oil tank 13 on the external hydraulic power source 7 side are connected via the pipe line 14 so that the hydraulic oil in the external oil tank 13 It is conceivable to keep the amount constant at all times. However, such a hydraulic device cannot be established because the pipe line 14 connecting the container-side oil tank 12 and the external oil tank 13 is long and exceeds the allowable suction pressure of the hydraulic pump 15. Further, in this hydraulic device, the external oil tank 13 needs to be of a hermetically sealed type, but the oil tank mounted on the existing tractor 6 is a ventilated type, so that the replacement cost of the oil tank increases. .

Therefore, an object of the present invention is to solve the problems of the prior art, and even if the operation of raising or lowering the deck of a vehicle-mounted container using the external hydraulic power source is repeated, the external hydraulic power source side An object of the present invention is to provide a hydraulic device for raising and lowering a deck of a vehicle-mounted container that does not increase or decrease the amount of oil in the oil tank and does not need to change the structure of an existing external hydraulic source.

[0008]

In the hydraulic apparatus for raising and lowering the deck of the vehicle-mounted container according to the present invention, the hydraulic oil returned from the hydraulic cylinder for raising and lowering the deck is returned to the external oil tank via the hydraulic cylinder for holding the oil amount. That is, the hydraulic oil returning from the rod-side hydraulic chamber of the deck lifting hydraulic cylinder is absorbed in the rod-side hydraulic chamber of the oil amount holding hydraulic cylinder.
Then, the hydraulic oil discharged from the cylinder head side hydraulic chamber is returned to the external oil tank by the movement of the piston of the hydraulic cylinder for maintaining the oil amount which is accompanied with this. Similarly, the hydraulic oil returning from the cylinder head side hydraulic chamber of the deck lifting hydraulic cylinder is absorbed in the cylinder head side hydraulic chamber of the oil amount holding hydraulic cylinder. Then, the hydraulic oil discharged from the rod-side hydraulic chamber is returned to the external oil tank due to the movement of the piston of the hydraulic cylinder for maintaining the oil amount that is accompanied with this.

At this time, the area ratio of the pressure receiving area of the cylinder head side hydraulic chamber and the pressure receiving area of the rod side hydraulic chamber of the hydraulic cylinder for raising and lowering the deck and the hydraulic cylinder for holding the oil amount is made the same. Assuming that this area ratio is 2: 1, in order to extend the hydraulic cylinder for raising and lowering the deck by a predetermined length,
When 2 liters of hydraulic oil is sent from the hydraulic pump to the cylinder head side hydraulic chamber of the deck lifting hydraulic cylinder, 1 liter of hydraulic oil is sent from the rod side hydraulic chamber as the piston of the deck lifting hydraulic cylinder moves. Is discharged. When this 1 liter of discharged oil is absorbed into the rod-side hydraulic chamber of the oil amount holding hydraulic cylinder, 2 liters of hydraulic oil is supplied from the cylinder head side hydraulic chamber as the piston of the oil amount holding hydraulic cylinder moves. Is discharged, and the discharged oil returns to the external oil tank. That is, when 2 liters of pressure oil is supplied from the external hydraulic source to the deck lifting hydraulic cylinder in order to expand and contract the deck lifting hydraulic cylinder, the external oil tank receives 2 liters of hydraulic oil from the oil amount holding hydraulic cylinder. Is returned, the amount of oil in the external oil tank does not increase or decrease. Therefore, according to the present invention, the amount of oil in the external oil tank does not increase or decrease even if the operation of raising or lowering the decks of a large number of automobile transport containers using the external hydraulic power source is repeated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A hydraulic system for raising and lowering a deck of an automobile transportation container according to an embodiment of the present invention will be described in detail below with reference to FIGS. 1 and 2.

The deck lifting hydraulic system of the present embodiment is for lifting the pair of front and rear upper decks 5 of the automobile transport container 3 shown in FIG. 3, and is shown in FIG. 1 and the hydraulic circuit shown in FIG. And an electric circuit. The hydraulic circuit and the electric circuit respectively include a portion provided on the container 3 side and a portion provided on the tractor 6 side (external hydraulic power source side) of the trailer 1 shown in FIG.

First, the hydraulic circuit of the hydraulic apparatus for raising and lowering the deck of this embodiment will be described with reference to FIG. The hydraulic circuit 20 on the side of the container 3 depicted in the upper half of FIG. 1 has a total of four sets of hydraulic cylinders 21, 22, 23, 24 for raising and lowering the pair of upper decks 5. Then, these deck lifting hydraulic cylinders 21, 22, 2
An electromagnetic switching valve 31, a pilot check valve 26, a throttle valve 27, and an electromagnetic switching valve 31,
32, 33 and 34 are respectively connected. In addition, these electromagnetic switching valves 31, 32, 33, 34 are provided with a conduit 35.
And the conduit 36 are connected. And the conduit 3
The hydraulic oil is supplied via 5 and the hydraulic oil is returned via the pipe 36.

Further, the hydraulic circuit 20 on the container 3 side has a pair of oil amount holding hydraulic cylinders 41R and 41L. The cylinder head side hydraulic chamber 41a and the rod side hydraulic chamber 41b of each of the oil amount holding hydraulic cylinders 41R and 41L are connected to each other by a pipe line 42 and a pipe line 43, respectively. Further, a throttle 45 is provided at an end portion of the pipeline 43 on the right side in the drawing on the side of the oil amount holding hydraulic cylinder 41R. The hydraulic oil returned from the deck lifting hydraulic cylinders 21, 22, 23, 24 is supplied to these oil amount holding hydraulic cylinders 41 via the pipe line 36 and the electromagnetic switching valve 46. The working oil discharged from the oil amount holding hydraulic cylinders 41 is returned via the electromagnetic switching valve 46 and the pipe line 47.

The hydraulic cylinder 2 for raising and lowering the deck
1, 22, 23, 24 and the cylinder head side hydraulic chambers 21a of the oil amount holding hydraulic cylinders 41R, 41L,
The area ratios of the pressure receiving areas of 22a, 23a, 24a, 41a and the pressure receiving areas of the rod side hydraulic chambers 21b, 22b, 23b, 24b, 41b are the same. That is, the hydraulic cylinders 21,22,23,24,41R, H ₂₁ respectively pressure receiving area of the cylinder head side hydraulic chambers of 41L, H
₂₂ , H ₂₃ , H ₂₄ , and H ₄₁ , and the pressure-receiving areas of the rod-side hydraulic chambers are R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , and R ₄₁ , respectively, H ₂₁ / R ₂₁ = H ₂₂ / R _{22 = H 23 / R 24 =} H 41 / R 41 = α can be expressed (equation 1) and.

The hydraulic cylinders 21 and 2 for raising and lowering the deck are also provided.
2, 23, 24 and a hydraulic cylinder 41R for holding the oil amount,
41L piston stroke, st ₂₁ , st
₂₂ , st ₂₃ , st ₂₄ , st ₄₁ , the piston stroke st of the oil amount holding hydraulic cylinders 41R, 41L
₄₁ is H ₄₁ × st ₄₁ ≧ (H ₂₁ × st ₂₁ + H ₂₂ × st ₂₂ + H ₂₃ × st ₂₃ + H ₂₄ × st ₂₄ ) (Formula 2) R ₄₁ × st ₄₁ ≧ (R ₂₁ × st ₂₁ + R ₂₂ × st ₂₂ + R ₂₃ × st ₂₃ + R ₂₄ × st ₂₄ ) (Formula 3)

On the other hand, the tractor 6 shown in the lower half of FIG.
The hydraulic circuit 50 on the side is separably connected to the conduits 35 and 47 on the container 3 side via a seal joint 51. The hydraulic oil supplied from the ventilated oil tank 52 installed in the tractor 6 is increased in pressure by the hydraulic pump 53 driven by the engine of the tractor 6, and then the main electromagnetic switching valve 54 and the conduit 55. , Seal fitting 51
Is supplied to the pipeline 35 on the container 3 side. Also,
The hydraulic oil that returns from the pipe line 47 on the container 3 side to the pipe line 56 on the tractor 6 side via the seal joint 51 returns to the oil tank 52 via the main electromagnetic switching valve 54.

Next, an electric circuit of the hydraulic apparatus for raising and lowering the deck of this embodiment will be described with reference to FIG. The electric circuit of the hydraulic apparatus for raising and lowering the deck of the present embodiment includes an electric circuit 60 on the container 3 side shown in the upper half of FIG. 2 and an electric circuit 70 on the tractor 6 side shown in the lower half of FIG. I have it. The electric circuit 70 on the tractor 6 side is connected to the connector 7
1, it is separably connected to the electric circuit 60 on the container 3 side.

The electric circuit 60 on the container 3 side has push button switches 61, 62 for operating electromagnetic switching valves 31, 32, 33, 34 for controlling the operation of the deck lifting hydraulic cylinders 21, 22, 23, 24. 63 and 64 are provided. Then, these push button switches 61, 6
2, 63, 64 are the deck up button 61a,
62a, 63a, 64a and a deck lowering button 61b,
It has 62b, 63b, and 64b. Further, the electric circuit 60 on the container 3 side includes a normally closed limit switch 65 and a normally open limit switch 66 for detecting the maximum extension state and the minimum reduction state of the oil amount holding hydraulic cylinder 41R, respectively, and the oil Quantity holding hydraulic cylinder 4
The relays 67 and 68 for operating the electromagnetic switching valve 46 for controlling the operation of No. 1 are provided. The electric circuit 70 on the tractor 6 side includes a battery 72 charged by a generator driven by the engine of the tractor 6.

Next, the operation of the hydraulic apparatus for raising and lowering the deck of the present embodiment having the above-mentioned structure will be described. In addition, the hydraulic cylinders 21, 22, 23 for raising and lowering the deck,
24 and the hydraulic cylinders 41R and 41L for holding the oil amount
Are provided in pairs, however, since these hydraulic cylinders can be regarded as one hydraulic cylinder, they will be treated as such in the following description.

First, when raising the front end of the front upper deck 5 of the container 3 shown in FIG. 3, the deck raising button 61a of the push button switch 61 is pushed. Then, the current supplied from the battery 72 causes the solenoid a of the electromagnetic switching valve 31 of the hydraulic cylinder 21 that moves up and down the front end of the front upper deck 5 to move toward the a-end side solenoid and the oil amount holding hydraulic cylinder 4.
1 flows to the a-side solenoid of the electromagnetic switching valve 46 and the solenoid of the main electromagnetic switching valve 54 on the tractor 6 side. As a result, the pressure oil supplied from the hydraulic pump 53 is supplied from the P port of the main electromagnetic switching valve 54 to the P port of the electromagnetic switching valve 31 via the pipeline 55, the seal joint 51 and the pipeline 35 on the container 3 side. To be done. Then, the pressure oil supplied to the P port of the electromagnetic switching valve 31 flows into the cylinder head side hydraulic chamber 21a from the A port of the electromagnetic switching valve 31 via the A port of the hydraulic cylinder 21 to expand the hydraulic cylinder 21. Raise the front end of the front upper deck 5.

At this time, the working oil discharged from the rod-side hydraulic chamber 21b as the deck lifting hydraulic cylinder 21 is extended extends from the B port of the deck lifting hydraulic cylinder 21 to the B port and the T port of the electromagnetic switching valve 31. , Pipeline 3
Solenoid switching valve 4 of oil pressure holding hydraulic cylinder 41
Reach P port 6 Then, this electromagnetic switching valve 46
The hydraulic oil that has reached the P port of No. 2 flows into the rod side hydraulic chamber 41b of the oil amount holding hydraulic cylinder 41 via the B port of the electromagnetic switching valve 42 and the B port of the oil amount holding hydraulic cylinder 41. As a result, the piston of the oil amount holding hydraulic cylinder 41 is displaced, so that hydraulic oil is discharged from the cylinder head side hydraulic chamber 41a of the oil amount holding hydraulic cylinder 41. The hydraulic fluid discharged from the cylinder head side hydraulic chamber 41a is supplied to the A port of the oil amount holding hydraulic cylinder 41, the T port of the electromagnetic switching valve 46, the pipe line 47, the seal joint 51, and the tractor 6 side pipe line 56. , And returns to the oil tank 52 via the main electromagnetic switching valve 54.

On the other hand, when lowering the front end of the front upper deck 5 of the container 3, the deck lowering button 61b of the push button switch 61 is pushed. Then, the current supplied from the battery 72 causes the b-side solenoid of the electromagnetic switching valve 31 of the deck lifting hydraulic cylinder 21, the b-side solenoid of the electromagnetic switching valve 46 of the oil amount holding hydraulic cylinder 41, and the main electromagnetic switching. It flows to the solenoid of valve 54. As a result, the pressure oil supplied from the hydraulic pump 53 is supplied from the P port of the main electromagnetic switching valve 54 to the P port of the electromagnetic switching valve 31 via the pipeline 55, the seal joint 51 and the pipeline 35 on the container 3 side. To be done. Then, the pressure oil supplied to the P port of the electromagnetic switching valve 31 flows into the rod side hydraulic chamber 21b from the B port of the electromagnetic switching valve 31 via the B port of the deck lifting hydraulic cylinder 21 and flows into the hydraulic cylinder 21. Shorten and lower the front end of the front upper deck 5.

At this time, the hydraulic oil discharged from the cylinder head side hydraulic chamber 21a along with the shortening of the deck lifting hydraulic cylinder 21 is A of the deck lifting hydraulic cylinder 21.
From the port to the A port and T port of the electromagnetic switching valve 31,
It reaches the P port of the electromagnetic switching valve 46 of the oil amount holding hydraulic cylinder 41 via the pipe line 36. The hydraulic oil that has reached the P port of the electromagnetic switching valve 46 is
Through the A port and the A port of the oil amount holding hydraulic cylinder 41 into the cylinder head side hydraulic chamber 41a of the oil amount holding hydraulic cylinder 41. As a result, the piston of the oil amount holding hydraulic cylinder 41 is displaced, so that the working oil is discharged from the rod side hydraulic chamber 41b of the oil amount holding hydraulic cylinder 41. Then, the hydraulic oil discharged from the rod-side hydraulic chamber 41b is B of the oil amount holding hydraulic cylinder 41.
It returns to the oil tank 52 via the port and the T port of the electromagnetic switching valve 46, the pipe line 47, the seal joint 51, the pipe line 56, and the main electromagnetic switching valve 54.

Next, the operation of the oil amount holding hydraulic cylinder 41 that operates as described above will be described. First, in order to extend the deck lifting hydraulic cylinder 21, it is assumed that S (milliliter) of pressure oil is made to flow from the hydraulic pump 53 into the cylinder head side hydraulic chamber 21a of the deck lifting hydraulic cylinder 21. The value of the extension of L (mm) of the deck lift hydraulic cylinder 21 by this, since the pressure receiving area of the cylinder head-side oil pressure chamber 21a is H ₂₁ (square _{millimeters), L × H 21 = S} ( Equation 4) which the, L = S / H ₂₁ (equation 5) Hence, the value of the quantity T of the hydraulic oil discharged from the rod-side hydraulic chamber 21b with the extension of the deck lift hydraulic cylinder 21 (ml) of the rod-side oil pressure Since the pressure receiving area of the chamber 21b is R ₂₁ (square millimeter), T = L × R ₂₁ = (S / H ₂₁ ) × R ₂₁ (Equation 6) Here, from (Equation 1), H ₂₁ / R ₂₁ = Since α, it is possible to obtain T = S / α (Equation 7).

On the other hand, when T (milliliter) of hydraulic oil flows from the rod side hydraulic chamber 21b into the rod side hydraulic chamber 41b of the oil amount holding hydraulic cylinder 41 as the deck lifting hydraulic cylinder 21 is extended, the oil is The piston of the quantity holding hydraulic cylinder 41 is displaced. If the displacement amount of this piston is X (mm), the pressure receiving area of the rod side hydraulic chamber 41b of the oil amount holding hydraulic cylinder 41 is R ₄₁ (square mm), so T = X × R ₄₁ (Equation 8) As a result, X = T / R ₄₁ (Formula 9) can be obtained. Therefore, if the amount of hydraulic oil discharged from the cylinder head side hydraulic chamber 41a due to the displacement of the piston of the oil amount holding hydraulic cylinder 41 is U (milliliter), the pressure receiving area of the cylinder head side hydraulic chamber 41a is H _41. (Square millimeter), U = X × H ₄₁ (Equation 10) Here, when X is eliminated by using (Equation 9), U = (T / R ₄₁ ) × H ₄₁ (Equation 11) Further, since H ₄₁ / R ₄₁ = α from (Equation 1), U = T × α (Equation 12) Furthermore, if T is eliminated using (Equation 7), then U = (S / α) × α = S (Equation 13) That is, as is clear from (Equation 13), S (milliliter) of hydraulic oil is pumped up from the oil tank 52 to extend the deck lifting hydraulic cylinder 21, and the hydraulic pump 53 moves the deck up and down. Towards the hydraulic cylinder 21 When pumping hydraulic oil from the oil amount holding hydraulic cylinder 41 U i.e. S (ml) is fed back to the oil tank 52.

Therefore, according to the hydraulic apparatus for raising and lowering the deck of the present embodiment, the oil tank 52 and the hydraulic pump 53 provided in the tractor 6 are used to raise or lower the upper decks 5 of the plurality of containers 3. Even if the above is repeated, the total amount of hydraulic oil in the oil tank 52 is constant. At the same time, the total amount of hydraulic oil contained in the hydraulic circuit on the container 3 side is also constant. This is exactly the same when the hydraulic cylinder 21 for raising and lowering the deck is shortened to lower the upper deck 5, or when the hydraulic cylinders 22, 23, 24 for other deck raising and lowering are respectively extended and lowered to raise and lower the upper deck 5. is there.

However, when operating the hydraulic cylinders 21, 22, 23, 24 for raising and lowering the deck, it is unavoidable that the hydraulic oil leaks, although it is a very small amount.
As a result, when the upper deck 5 is repeatedly moved up and down, the piston of the oil amount holding hydraulic cylinder 41 gradually shifts from the initial position and eventually bottoms out on the most extended side or the most shortened side in the cylinder. Then, the oil amount holding hydraulic cylinder 41 becomes the deck lifting hydraulic cylinders 21, 22, 23, 2.
It becomes impossible to receive the hydraulic oil returned from the No. 4 and the upper deck 5 cannot be moved up and down.

Therefore, in the deck lifting hydraulic system of this embodiment, as shown in FIG. 2, the limit switches 65 and 66 are used to detect the most extended state or the most shortened state of the oil amount holding hydraulic cylinder 41R. It has become. When either of these limit switches 65, 66 is activated, the deck lift push button 6
Even if 1, 62, 63, 64 are operated, the electromagnetic switching valve 46 of the oil amount holding hydraulic cylinder 41 is maintained in the neutral state.
As a result, the deck lifting hydraulic cylinders 21, 22, 2
The hydraulic oil returning from 3, 24 to the oil amount holding hydraulic cylinder 41 via the pipe line 36 returns directly from the P port of the electromagnetic switching valve 46 to the oil tank 52 via the T port and the pipe line 47. Hydraulic cylinders 21, 22 for raising and lowering the deck
The expansion and contraction operations of 23 and 24 will not be disabled.

Incidentally, these limit switches 65, 6
6 is a pair of oil amount holding hydraulic cylinders 41 shown in FIG.
Of the R and 41L, these oil amount holding hydraulic cylinders 41
Detects the most extended state or the most shortened state of the oil amount holding hydraulic cylinder 41R on the side where the throttle 45 provided in the middle of the pipeline 43 that connects the R and 41L rod side hydraulic chambers 41b to each other is provided. Is being done. This is one of the pair of oil amount holding hydraulic cylinders 41R, 41L, and the throttle 4
Oil quantity holding hydraulic cylinder 41R on the side where 5 is provided
This is because the state is later than the hydraulic cylinder 41L for holding the oil amount on the opposite side, and is in the shortest state and the most extended state. As a result, the pair of oil amount holding hydraulic cylinders 41R, 41R
Compared to the case where limit switches are provided on both L,
The configuration of the electric circuit 60 can be simplified.
The throttle 45 is connected to a pair of oil amount holding hydraulic cylinders 41.
A hydraulic cylinder 41 for holding the oil amount in the middle of a pipe line 42 that connects the R and 41L cylinder head side hydraulic chambers 41a to each other.
You may provide in the part by the side of R.

That is, as is apparent from the above description, according to the deck lifting hydraulic device of this embodiment, the hydraulic pump 53 and the oil tank 5 provided on the tractor 6 side are provided.
Even if the operation of raising or lowering the upper decks 5 of the plurality of containers 3 is repeated by using 2, the amount of hydraulic oil in the oil tank 52 does not increase or decrease. Further, the oil amount holding hydraulic cylinders 41R and 41L provided in the container 3 are
Since a hydraulic cylinder having the same structure as the deck lifting hydraulic cylinder is used, it can be manufactured at low cost. The oil amount holding hydraulic cylinders 41R, 41R
Since L is divided into two small diameter hydraulic cylinders, the mounting space for the container 3 can be reduced.
In addition, the deck lifting hydraulic cylinders 21, 22, 23, 2
When the pistons of the oil amount holding hydraulic cylinders 41R and 41L bottom-bottom toward the most extended side or the most shortened side due to the leakage of hydraulic oil from No. 4, the hydraulic oil returned from the deck lifting hydraulic cylinder is Since the structure is such that the oil is returned directly to the oil tank 52 without using the holding hydraulic cylinder, there is no hindrance to the lifting operation of the upper deck 5. And
Since the bottom switches of the piston of the oil amount holding hydraulic cylinder 41R alone are detected by the limit switches 65 and 66, the structure of the electric circuit 60 on the container 3 side can be simplified.

Although the deck lifting hydraulic device according to one embodiment of the present invention has been described in detail above, it goes without saying that the present invention is not limited to the above-described embodiment and various modifications can be made. For example, in the above-described embodiment, as the oil amount holding hydraulic cylinder, a hydraulic cylinder having the same structure as the deck lifting hydraulic cylinder is used, but instead of such a hydraulic cylinder, it is used for increasing the hydraulic pressure. A booster (booster) to be used may be used for oil amount conversion. In this case, unlike the hydraulic cylinder, the rod does not protrude from the cylinder, so that the installation space of the oil amount holding hydraulic cylinder can be reduced.

[0032]

According to the present invention, there is provided a hydraulic apparatus for raising and lowering a deck of an automobile transportation container, which retains an amount of hydraulic oil returning from the hydraulic cylinder for raising and lowering a deck when the deck is raised and lowered and having the same area ratio as the hydraulic cylinder for raising and lowering the deck. Since it is configured to return to the oil tank of the external hydraulic source via the hydraulic cylinder for
Even if the operation of raising or lowering the decks of a plurality of containers using the external hydraulic power source is continuously repeated, the total amount of hydraulic oil in the oil tank of the external hydraulic power source does not change. Thus, according to the present invention, it is possible to prevent the total amount of hydraulic oil in the oil tank of the external hydraulic source from changing without changing the structure of the existing external hydraulic source.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic device for raising and lowering a deck of an automobile transportation container according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a hydraulic device for raising and lowering a deck of an automobile transportation container according to an embodiment of the present invention.

FIG. 3 is a side view of the trailer and the container for explaining the procedure for mounting the vehicle in the vehicle transportation container.

FIG. 4 is a side view of the trailer and the container for explaining the procedure for mounting the vehicle in the vehicle transportation container.

FIG. 5 is a side view of the trailer and the container for explaining the procedure for mounting the vehicle in the vehicle transportation container.

FIG. 6 is a hydraulic circuit diagram of a conventional deck lifting hydraulic device.

[Explanation of symbols]

1 trailer 2 loading platform 3 Car-mounted container 4 deck lifting hydraulic cylinder 5 Upper deck 6 tractors 7 External hydraulic power source 8 cars 9 road board 10 Lower deck 11 Conventional hydraulic circuit 12 oil tanks 13 External oil tank 14 pipelines 15 Hydraulic pump 20 Container side hydraulic circuit 21, 22, 23, 24 Deck lifting hydraulic cylinder 31, 32, 33, 34 Solenoid switching valve 41 Oil pressure holding hydraulic cylinder 42, 43 conduit 45 aperture 46 Solenoid switching valve 47 Hydraulic oil return line 50 External hydraulic power source side hydraulic circuit 51 seal fitting 52 oil tank 53 Hydraulic pump 54 Main solenoid switching valve 60 Container side electric circuit 61, 62, 63, 64 push button switches 65, 66 Proximity switch 67 68 Relay 70 External hydraulic power source side electric circuit 71 connector 72 battery

Continuation of the front page (56) Reference JP-A-7-2099 (JP, A) JP-A-6-100177 (JP, A) Actually open 63-172741 (JP, U) Actually open 2-144836 (JP , U) Actual development Sho 63-57134 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60P 3/08 F15B 21/00

Claims (4)

(57) [Claims] 1. A hydraulic cylinder for raising and lowering a deck, an external hydraulic source for supplying pressure oil to the hydraulic cylinder, and a hydraulic oil for supplying hydraulic oil to the external hydraulic source and returning from the hydraulic cylinder. A deck lifting hydraulic apparatus comprising: an external oil tank for storing, wherein the container-side hydraulic pipeline, the external hydraulic power source, and the external oil tank-side hydraulic pipeline are separably connected via a joint. An oil amount holding hydraulic cylinder interposed in the middle of a pipe line connecting the external oil tank and the deck lifting hydraulic cylinder, the oil amount holding hydraulic cylinder, the deck lifting hydraulic cylinder, and the external A switching valve for switching connection of a pipeline extending to an oil tank is provided on the container side, respectively, and the deck lifting hydraulic cylinder and the oil amount holding unit are provided. When the area ratio between the pressure receiving area of the rod side hydraulic chamber of the hydraulic cylinder and the pressure receiving area of the cylinder head side hydraulic chamber is the same, and when the switching valve is used to return hydraulic fluid from the rod side hydraulic chamber of the deck lifting hydraulic cylinder. Connecting the rod-side hydraulic chamber of the deck lifting hydraulic cylinder to the rod-side hydraulic chamber of the oil amount holding hydraulic cylinder, and connecting the cylinder head side hydraulic chamber of the oil amount holding hydraulic cylinder and the external oil tank. When the hydraulic fluid returns from the cylinder head side hydraulic chamber of the deck lifting hydraulic cylinder, the cylinder head side hydraulic chamber of the deck lifting hydraulic cylinder and the cylinder head side hydraulic chamber of the oil amount holding hydraulic cylinder are communicated. And the rod-side hydraulic chamber of the oil amount holding hydraulic cylinder and the external oil tank. Deck lifting hydraulic device according to claim. 2. A sensor for detecting the most extended state and the most shortened state of the oil amount holding hydraulic cylinder is further provided, and the fact that the oil amount holding hydraulic cylinder is in the most extended state or the most shortened state is provided. 2. The deck lifting hydraulic device according to claim 1, wherein the switching valve is controlled so that the working oil returning from the deck lifting hydraulic cylinder returns directly to the external oil tank when detected by a sensor. 3. A plurality of the oil amount holding hydraulic cylinders are provided, and the hydraulic lines for connecting the cylinder head side hydraulic chambers of these oil amount holding hydraulic cylinders are connected in the middle of the pipeline or between the rod side hydraulic chambers. A throttle is provided in the middle of each of the pipelines, and the sensor is arranged such that, of the plurality of oil amount holding hydraulic cylinders, the oil amount holding hydraulic cylinder to which hydraulic oil is supplied through the throttles is in the most extended state or the most extended state. The hydraulic apparatus for raising and lowering a deck according to claim 1 or 2, wherein a shortened state is detected. 4. The deck lifting device according to claim 1, wherein the deck is a deck of an automobile transportation container which is carried by a vehicle while mounting an automobile.