JPH0518321Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of a garbage collection vehicle equipped with a dedicated cylinder device for opening and closing the tailgate.

[Summary of the idea]

This invention is based on a garbage collection vehicle equipped with a cylinder device dedicated to opening and closing the tailgate, and a pilot check valve attached as a part of the cylinder device, and a chamber in the device on the side where the cylinder device is extended. A first pipe line communicating through the check valve, a second pipe line for applying pilot pressure to the pilot check valve, and the first and second pipe lines are selected in a one-to-one correspondence relationship. a switching valve that is connected to the pressure oil pipe and the oil drain pipe, respectively; a filter that is connected to the oil tank side end of the oil drain pipe to cause a head loss; and a chamber in the device that contracts the cylinder device; By providing a third pipe line that directly communicates with the drain oil pipe line interposed between the switching valve and the filter, the danger of the tailgate being unexpectedly lowered during the tailgate opening/closing operation is prevented, and the cylinder device This ensures good lubrication of the movable parts, improves the life of the cylinder device, and further improves the contraction movement of the cylinder device.

[Conventional technology]

An example of a prior art garbage collection vehicle equipped with a dedicated cylinder device for opening and closing a tailgate is disclosed in Japanese Patent Publication No. 56-48402.

In this example, a single-acting cylinder device 1 is used as shown in FIG. It is configured to be selectively connected to the oil pipe line 8 or the oil drain pipe line 9.

Therefore, when raising the tailgate to open the garbage collection device, move the switching valve 5 to the right in the same figure.
While opening the check valve 3 with hydraulic pressure P, open the chamber 1a.
The cylinder device 1 is extended by sending hydraulic oil into the cylinder. For example, when the tailgate is in the raised position, the switching valve 5 is returned to the position shown in FIG.
The oil pressure in a is maintained at the oil pressure P of the pressure oil pipe line 8.

Next, in order to lower the tailgate and close the dust collection device, the switching valve 5 is moved to the left in the same figure, and the hydraulic oil in the chamber 1a is sent to the drain oil pipe 9 to contract the cylinder device 1. At this time, the pressure oil pipe line 8 is short-circuited to the drain oil pipe line 9 by the switching valve 5. Furthermore, since the hydraulic oil discharged from the chamber 1a passes only through the throttle valve 2, the tailgate is gently lowered.

Next, as a conventional technology of a garbage collection vehicle using a double-acting type cylinder device as the cylinder device, there is one disclosed, for example, in Japanese Patent Publication No. 54-20728.

In this example, as shown in FIG.
The chamber 10a (hereinafter referred to as "the first chamber 10a") that extends the
"Chamber") is connected through a pipe line 12 containing a pilot check valve 11 with a throttle valve 2, and also to a chamber 10 on the side that deflates the cylinder device 10.
b (hereinafter abbreviated as "second chamber") are each connected to the switching valve 5 via the pipe line 15, and selectively connected to the pressure oil pipe line 8 or the drain oil pipe line 9, respectively. The pilot pressure applied to the pilot check valve 11 is applied to the pilot check valve 11 through a pipe 16 branched from the pipe 15.

Thus, in order to raise the tailgate and open the dust collection device, move the switching valve 5 to the right in the figure, push open the pilot check valve 11 with hydraulic pressure P, and feed hydraulic oil into the first chamber 10a to open the cylinder device. Extend 10. At this time, the hydraulic oil in the second chamber 10b is discharged to the oil drain pipe 9 via the oil passage 15.

Next, when the tailgate is lowered to close the dust collection device, the switching valve 5 is moved to the left in the figure, hydraulic oil is sent into the second chamber 10b, and the cylinder device 10 is contracted. At this time, the hydraulic oil in the first chamber 10a is discharged to the oil drain pipe 9 through the oil passage 12, but because the hydraulic pressure P of the hydraulic oil flowing through the oil passage 15 is applied to the pilot check valve 11 as pilot pressure. The discharged oil from the first chamber 10a flows not only through the throttle valve 2 but also through the pilot check valve 11.

(Problem to be solved by the invention) However, when the single-acting type cylinder device 1 shown in FIG. Even if it is closed as shown, if there is a leakage of hydraulic oil in the switching valve 5, there is a problem that the tailgate will descend under its own weight.

Furthermore, if the pipe line 4 is damaged at the portion 4a between the throttle valve 2 and check valve 3 and the cylinder device 1 and hydraulic oil leaks, there is a danger that the tailgate will rapidly lower and cause unexpected damage. There is.

Furthermore, since the cylinder device 1 is a single-acting type,
No hydraulic oil is supplied to the chamber 1c, which occupies the opposite side of the piston 1b from the chamber 1a. For this reason, the lubrication within the cylinder device 1 becomes insufficient, which has an adverse effect on the lifespan of the cylinder device 1.

On the other hand, a double-acting cylinder device 10 shown in FIG.
When using a cylinder device 1, instead of lowering the tailgate by its own weight as in the single-acting cylinder device 1, hydraulic oil with a hydraulic pressure P is pumped into the second chamber 1.
This is done by supplying it to 0b.

Therefore, in order to ensure safety when the tailgate unexpectedly descends, if the tailgate comes into contact with the safety rod (described below) that protrudes from the rear end of the garbage collection vehicle when it descends, the above-mentioned safety bar will fail due to overload. There is a risk that the pole may be damaged or the garbage truck may be damaged.

In view of the above-mentioned points, the present invention provides a garbage collection vehicle in which the raised tailgate does not come down unexpectedly or the safety rod etc. are not damaged due to overload while the tailgate is being lowered. This is what we provide.

[Means for solving problems]

The present invention provides a garbage collection vehicle equipped with a dedicated cylinder device for opening and closing the tailgate, and a pilot check valve that is provided integrally with the cylinder device and forms a part of the cylinder device, and an extension of the cylinder device. The first valve is connected to the chamber in the device on the side to be operated through the pilot check valve.
a second pipe line for applying pilot pressure to the pilot check valve, and a pressure oil pipe line for supplying high pressure hydraulic oil to the cylinder device;
an oil drain pipe for returning the hydraulic oil from the cylinder device to the oil tank; a filter connected to the end of the oil tank side of the oil drain pipe to filter the hydraulic oil and generate a water head loss; and the cylinder device. The end of the first pipe line is communicated with the end of the pressure oil pipe line and the end of the second pipe line is connected to the end of the oil drain pipe line in order to extend the oil pipe line, and the cylinder device is contracted. For this purpose, the end of the first pipe line is communicated with the end of the oil drain pipe line, and the end of the second pipe line is connected with the end of the pressure oil pipe line, and the neutral position thereof is freely selected. A garbage collection vehicle is operated by a switching valve that can be switched from one side to the other, and a third pipe line that directly communicates a chamber in the device on the side that contracts the cylinder device with the oil drain pipe that is interposed between the switching valve and the filter. Configured.

[Effect]

Therefore, since there is no conduit between the cylinder device and the pilot check valve as in the past, there is no possibility that this conduit could be damaged and the tailgate could suddenly drop suddenly. .

In addition, by operating the switching valve and connecting the first pipe line and the second pipe line to the pressure oil line and the oil drain line, respectively, the hydraulic oil with a predetermined oil pressure pushes up the pilot check valve, and the cylinder Since it flows into the chamber in the device on the side where the device is extended, the cylinder device is extended and the tailgate is raised. Further, in this case, since the second pipe line is connected to the drain oil pipe line, no pilot pressure is applied to the pilot check valve. Furthermore, since the third pipe line is also connected to the drain oil pipe line, there is no risk of interfering with the above-mentioned extending operation of the cylinder device.

Next, when lowering the tailgate, operate the switching valve and connect the first pipe line and the second pipe line to the drain oil pipe line and the pressure oil line, respectively, and the oil pressure in the pressure oil line can be checked by the pilot. The pilot check valve opens because it acts as pilot pressure on the valve. Further, as a result, the cylinder device tends to descend due to the weight of the tailgate, so the hydraulic oil in the chamber within the device on the side where the cylinder device is extended is discharged to the oil drain pipe through the first pipe. The cylinder arrangement is thus retracted and the tailgate is lowered towards its lowered position. Note that in the cylinder device, since hydraulic oil is supplied to the chamber in the device on the side to be contracted from the oil drain pipe through the third pipe, there is no possibility that the movable parts in the cylinder device become insufficiently lubricated.

〔Example〕

An embodiment in which the present invention is applied to a garbage collection vehicle equipped with a dedicated cylinder device for opening and closing a tailgate will be described below with reference to FIGS. 1A to 2C.

As shown in FIG. 1A, the garbage collection device 17 of the garbage collection vehicle consists of a body 18 for storing garbage and a tailgate 22 for closing an opening 19 at the rear of the body 18. The opening 19 is connected to the tailgate 2 as shown in the figure.
2, and garbage is thrown into the tailgate 22 from the garbage loading port 23 at the rear of the tailgate 22.

The thrown garbage is sent into the body 18 and accumulated therein by the functions of a rotatable conveyor panel 24 disposed inside the tailgate 22 and a swingable ram panel 39.

Further, in order to dump the dust accumulated in the body 18 as described above, as shown in FIG. 1B, the tailgate cylinder device 25 is extended, the tailgate 22 is raised to open the opening 19, and then The body cylinder device 26 shown in FIG. 1A is extended, and the body 18 is rotated clockwise around the pivot shaft 29 in the same figure and tilted.

That is, as shown in FIG. 1A, a pair of left and right brackets 31 are protruded from a frame 30 arranged at the rear end of the body 18 of the garbage collection vehicle, and a tailgate 22 is attached to a shaft 32 supported by these brackets 31. A protruding bracket 33 is pivotally supported.

Further, a second bracket 36 is provided protruding from the frame 30 in the vicinity of and parallel to the bracket 31, and at the upper end of the second bracket 36, one end of a ram panel cylinder device 37 has its axis aligned with the shaft 32. One end of the tailgate cylinder device 25 is pivotally connected to the lower end of the second bracket 36.

The other end of the ram panel cylinder device 37 is connected to the upper end of the ram panel 39 whose intermediate portion is pivoted to the tailgate 22 via the pivot shaft 38.
The other end of the tailgate cylinder device 25 is
The deflector 40 extends between the left and right side plates 22a of the tailgate 22 and is pivotally connected to a bracket 43 projecting from the deflector 40.

Note that the conveyor panel 24 is a winding transmission device 44.
It is rotated by a hydraulic motor 45 via. Further, reference numeral 46 in the figure is a safety rod, which comes into contact with the tailgate 22 when the ascending tailgate 22 unexpectedly descends as shown in FIG. This is to prevent this from happening. The safety rod 46 can be retracted as shown by the dotted line in FIG. 1A when the tailgate is normally lowered.

By the way, a pair of tailgate cylinder devices 2
5 includes a pilot check valve 4 shown in FIG. 2A.
7 are provided integrally with these cylinder devices 25, respectively, and constitute a part of the cylinder device 25. The first pipe line 50 then passes through the pilot check valve 47 and the tailgate cylinder device 2.
5, the chamber in the device on the side where the
It is communicated with the chamber 51. Also, in order to apply pilot pressure to the pilot check valve 47,
A second pipe line 5 is connected to the pilot check valve 47.
2 are connected.

Next, the 4-port, 3-position electromagnetic switching valve 53 shown in FIG. 2A is placed in the neutral position shown in the same figure, that is, the position where the hydraulic oil circuit is completely cut off, and when the switching valve 53 is moved to the left in the figure. position (FIG. 2B), that is, in order to extend the cylinder device 25, the end of the first pipe line 50 is placed at the end of the pressure oil pipe line 8, and the second
The position where the ends of the pipe lines 52 are connected to the ends of the drain oil pipe line 9, and the position where the switching valve 53 is moved to the right in the figure (Fig. 2C), that is, the position where the switching valve 53 is moved to the right side in the figure (Fig. 2C), that is, the first position in order to contract the cylinder device It is possible to freely switch between the positions where the end of the pipe 50 is connected to the end of the oil drain pipe 9 and the end of the second pipe 52 is connected to the end of the pressure oil pipe 8.

High-pressure hydraulic oil pressurized by an oil pump 56 is supplied to the pressure oil pipe line 8 from an oil tank 64 .
Further, the oil drain pipe 9 connects a predetermined port of the electromagnetic switching valve 53 and the oil tank 64.

A filter 60 for filtering the hydraulic oil is attached to the end of the oil drain pipe 9 on the oil tank 64 side, but this filter 60 naturally causes a head loss due to the above-mentioned filtering action. Further, a relief valve 58 is interposed between the pressure oil pipe line 8 and the drain oil pipe line 9, as shown in FIG. 2A.

Next, the chamber in the device on the side where the cylinder device 25 is contracted, that is, the second chamber 59 is the third chamber.
The switching valve 53 and the filter 6 are connected to each other by the pipe line 63.
0 and is directly connected to the drain oil pipe 9 interposed therebetween. As a result, the pressure of the hydraulic oil flowing in the third pipe line 63 is higher than that of the hydraulic oil in the oil tank by at least the head loss in the filter 60.

Next, the operation of the garbage collection vehicle constructed as described above will be described. First, when the electromagnetic switching valve 53 is switched from the neutral position shown in FIG. 2A to the position shown in FIG. , the valve 47 is pushed open and the water flows into the first chamber 51 . The cylinder device 25 is therefore extended and the tailgate 22 is raised.

Note that at this time, the pressure difference between the hydraulic oil flowing into the first chamber 51 from the first pipe line 50 and the hydraulic oil flowing out from the second chamber 59 into the third pipe line 63 is sufficiently large. The hydraulic oil discharged into the oil tank 64 through the third pipe line 63 does not act to prevent the cylinder device 25 from expanding.
Further, since the second pipe line 52 is also connected to the drain oil pipe line 9, no pilot pressure is applied to the pilot check valve 47.

Next, when the tailgate 22 reaches the raised position shown in FIG. 1B, if the switching valve 53 is returned to the neutral position shown in FIG. 2A, the supply of hydraulic oil to the first chamber 51 is cut off, but at the same time the pilot Since no pressure is applied to the pilot check valve 47, the hydraulic fluid in the first chamber 51 is transferred to the pilot check valve 47.
No leakage occurs due to the action of Therefore, the tailgate 22 can be reliably held in the raised position shown in FIG. 1B.

Next, in order to lower the tailgate 22, the switching valve 53 is moved to the position shown in FIG. 2C. As a result, the hydraulic oil at the hydraulic pressure P acts as pilot pressure on the pilot check valve 47 through the second pipe line 52, so the pilot check valve 47 opens.
The hydraulic fluid in the first chamber 51 is transferred to the first conduit 50 due to the piston 65 trying to move to the left in FIG. 2C mainly due to the weight of the tailgate 22.
leaks inside. After that, the oil is discharged to the drain oil pipe 9 via the switching valve 53. Therefore, the cylinder device 25
retracts and the tailgate 22 is lowered until it reaches the lowered position shown in FIG. 1A.

At this time, as shown in FIG. 2C, when the piston 65 starts to move to the left, the piston 65 is placed in the second chamber 59, which is only in communication with the third conduit 63 and is in a nearly sealed state. A negative pressure is generated which is proportional to the above movement of .

On the other hand, the hydraulic oil discharged from the first chamber 51 through the first pipe line 50 and the switching valve 53 to the drain oil pipe line 9 is reduced by the water head loss when a part of the hydraulic oil passes through the filter 60. have at least a corresponding positive pressure.

Therefore, a pressure difference is generated between the second chamber 59 and the oil drain pipe 9, so that the remaining hydraulic oil in the first chamber 51 discharged into the oil drain pipe 9 is smoothly transferred into the second chamber 59. There will be an influx into In other words, the flow of hydraulic oil into the second chamber 59 depends not only on the negative pressure generated in the second chamber, but also on the operation of the hydraulic oil flowing out from the first chamber 51 and the relief valve 58 into the oil drain line 9. The back pressure provided by the oil is also actively used to improve the contraction movement of the cylinder device 25.

Although the present invention has been described above with reference to embodiments, the above-mentioned embodiments do not limit the present invention, and various modifications can be made based on the technical idea of the present invention. For example, the cylinder device 25 for the tailgate
do not necessarily have to be two sets as shown in FIG. 2A, but may be one set or two or more sets.

Further, although the three-position switching valve 53 is used in the embodiment, any switching valve may be used as long as the pressure oil pipe 8 can be selectively connected to the first pipe 50 or the second pipe 52. There is no problem.

Further, in the embodiment, a cylinder device is used for dumping, but a hydraulic motor or the like may be used as long as a holding pressure P is always generated during dumping and the dumping state can thereby be maintained.

[Effect of idea]

In this design, the pilot check valve is provided directly on the cylinder device without intervening a pipe line between the cylinder device and the pilot check valve, so there is a danger that the pipe line may be damaged and the tailgate may fall unexpectedly. is completely unthinkable.

In addition, in this invention, the tailgate's own weight is mainly used to lower the tailgate from the raised position, so if the tailgate falls unexpectedly or by mistake and comes into contact with, for example, a safety rod, the safety rod or There is no fear that the garbage collection vehicle will be damaged by overload through this safety rod.

In addition, with this invention, hydraulic oil is supplied to the chamber inside the device on the side that contracts the cylinder device when the cylinder device contracts, so the movable parts of the cylinder device may lack lubrication or dust may accumulate on these movable parts. There is no fear that the cylinder device's lifespan will be shortened due to intrusion.

Furthermore, in this invention, a filter is connected to the oil tank side end of the oil drain pipe, causing a head loss.
When the cylinder device contracts, the hydraulic oil flowing out from the first chamber or the relief valve into the oil drain pipe has a predetermined back pressure. Therefore, this back pressure is
This results in a significant improvement in the contraction movement of the cylinder device.

[Brief explanation of the drawing]

Figures 1A to 2C show an embodiment in which this invention is applied to a garbage collection vehicle equipped with a dedicated cylinder device for opening and closing the tailgate.
Figures 1 and 1B are longitudinal sectional views of the rear of the same garbage collection vehicle when the tailgate is lowered and raised, respectively, Figure 2A is a hydraulic oil circuit diagram of the cylinder device for the tailgate (the switching valve is in the neutral position), and Figure 2B 2C and 2C are hydraulic oil circuit diagrams respectively showing the expansion and contraction of the above cylinder device. Also the third
Figures 4 and 4 show hydraulic oil circuit diagrams of conventional tailgate cylinder devices. Figure 3 is a hydraulic oil circuit diagram when a single-acting cylinder device is used, and Figure 4 is a hydraulic oil circuit diagram for a double-acting cylinder device. FIG. 3 is a hydraulic oil circuit diagram when the device is used. In addition, in the symbols used in the drawings, 8...Pressure oil pipe line, 9...Drain oil pipe line, 22...Tail gate, 25...Cylinder device for tail gate, 47
... Pilot check valve, 50 ... First pipe line, 51 ... First chamber (chamber in the device),
52...Second pipe line, 53...Solenoid switching valve, 59
...Second chamber (chamber within the device), 60...
Filter, 63...Third pipe line, 64...Oil tank.

Claims (1)

[Scope of Claim for Utility Model Registration] In a garbage collection vehicle equipped with a dedicated cylinder device for opening and closing the tailgate, a pilot check valve that is provided integrally with the cylinder device and forms a part of the cylinder device; a first conduit communicating with a chamber in the device on the side where the cylinder device is extended via the pilot check valve; a second conduit for applying pilot pressure to the pilot check valve; A pressure oil pipe for supplying hydraulic oil, an oil drain pipe for returning the hydraulic oil from the cylinder device to the oil tank, and a drain pipe connected to the oil tank side end of the oil drain pipe to filter the hydraulic oil. and a filter that causes a water head loss, and the first filter for extending the cylinder device.
a state in which an end of the pipe line is communicated with an end of the pressure oil pipe line and an end of the second pipe line with an end of the oil drain pipe line, and the first pipe line is connected in order to contract the cylinder device. a switching valve capable of freely selecting and switching from a neutral position to a state in which an end of the second pipe is connected to an end of the oil drain pipe and an end of the second pipe is connected to an end of the pressure oil pipe; A garbage collection vehicle, comprising: a third pipe line that directly communicates a chamber in the apparatus on the side where the cylinder apparatus is contracted with the oil drain pipe interposed between the switching valve and the filter.