JPH0475903A - Hydraulic controller for dust collecting vehicle - Google Patents

Abstract

PURPOSE:To increase body locking force by connecting a hydraulic pump with a pair of cylinders so that they may be made a thread take-up lever type to constitute a variable capacity type, and holding a body in a lowering direction when the changing-over switch of a dust processing device is at its neutral position to set pump delivery at zero. CONSTITUTION:While running, a body is at its low position, a detecting switch 16 turns on, and changing-over switch 27 is at its neutral position. When a main switch 26 closes, therefore, oil pressure flows to the rod side of a dumping switch 9, and the body keeps a lowering finish condition to prevent the body from floating. After completion of lowering the dumping cylinder, the pressure of a pump output circuit rises rapidly. With the pressure rising, the contact pressure maintaining control valve 24 of a pump P comes into action, and the discharge rate of the hydraulic pump P is controlled so that it may become zero by the first and second control cylinders 21, 22.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a hydraulic control device for a garbage collection vehicle, in particular, a variable displacement hydraulic pump that is constantly driven via a flywheel PTO. The present invention relates to a hydraulic control device for a garbage collection vehicle that maintains the body in a lowered position to prevent the body from floating while traveling.

[Conventional technology]

For example, the Japanese Patent Publication No. 1-5700 is a system that aims to reduce costs by directly connecting a variable displacement pump to the flywheel PTO without using an expensive electromagnetic clutch.
No. 1 is known. This is done by installing a solenoid valve in the discharge pipe of the hydraulic pump, and by switching the solenoid valve to block the discharge pipe when the garbage truck is running, the discharge amount of the hydraulic pump becomes zero, and as a result, the engine It is designed to reduce the power to zero.

In addition, in order to strengthen the locking force of the body 1 and prevent the body 1 from lifting when the garbage collection vehicle is running, a subframe 12 is attached to the chassis frame 11.
Generally, a body lock device 15 is installed between the body 1 and the body 1 (see FIG. 2).

Normally, the combined center of gravity of the body 1 and the tailgate 2 is located forward of the dump fulcrum (dump shaft 10), but if heavy garbage is loaded to the rear or the tailgate 2 When heavy garbage is piled up inside, the center of gravity may move to the rear of the dump fulcrum, causing the body 1 to float up. Furthermore, most of the various loading devices, such as the container tilting device for loading the garbage inside the container into the tailgate 2, the hopper and hopper tilting device of the garbage collection vehicle with a crane, are attached to the rear of the tailgate 2. Therefore, the conditions are even worse for the body 1 to rise due to the movement of the center of gravity. In particular, when the garbage collection vehicle is running, there is also vertical movement while the vehicle is running.
Furthermore, the body 1 becomes more likely to float up.

Here, a conventionally commonly used body lock device 1 is shown.
No. 5 uses spring force to hold it due to cost considerations.

[Problem to be solved by the invention]

However, in the body locking device using the spring force described above, if you try to increase the locking force to reliably prevent the body from lifting up, you will also need to increase the dumping force to overcome this, which increases weight and cost. There was a problem that it could lead to

In view of the above, the present invention provides a hydraulic pump with a flywheel PT.
It is an object of the present invention to provide a vehicle which is constantly driven via a motor vehicle and whose locking force for preventing the body from lifting during running is strengthened without being affected by dumping force.

[Means to solve the problem]

In order to achieve the above object, the hydraulic control device for a garbage collection vehicle according to the present invention includes a garbage disposal device consisting of a rotating plate and a pushing plate at the rear of the body dumped by a dump cylinder and an electromagnetic switching valve for the dump cylinder. In the hydraulic control device for a garbage collection vehicle, the built-in tailgate is connected and pressure oil is supplied to each actuator of the dump cylinder and the garbage processing device from a hydraulic pump driven via a flywheel PTO. Hydraulic pump first on swash plate
The control cylinder and the second control cylinder are configured in a variable volume type JI type in which the control cylinder and the second control cylinder are connected in a balance type, and a detection switch is provided to detect that the body is in the lowered position, and when the changeover switch of the garbage processing device is in the neutral position, The lowering solenoid of the electromagnetic switching valve is operated to hold the body in the lowering direction, and the first and second control cylinders are controlled so that the discharge amount of the hydraulic pump becomes zero.

[For production]

According to the present invention configured as described above, when traveling with the body lowered, the detection switch detects that the body is in the lowered position, and the lowering solenoid of the electromagnetic switching valve for the dump cylinder detects that the body is in the lowered position. By operating the lever dump cylinder in the direction of lowering the body, this dumping force strengthens the locking force of the body to reliably prevent this lifting, and at the same time, by reducing the discharge amount of the hydraulic pump to zero at this time. , the influence on driving can be reduced.

〔Example〕

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

As shown in FIG. 2, the garbage collection vehicle is equipped with a tailgate 2 connected to the rear part of the body 1, and inside the tailgate 2 is a garbage disposal device consisting of a rotary plate 3 and a push plate 4. 5 is built-in. The rotary plate 3 is rotated by a rotary plate hydraulic motor 6, and the pushing plate 4 is vertically swung by the expansion and contraction of a pushing plate cylinder 7.

Further, the tailgate 2 swings up and down by the drive of the tailgate lift cylinder 8, and the body 1 moves between the subframe 12 on the chassis frame 11 around the dump shaft 10 by the drive of the dump cylinder 9. The vehicle is dumped and locked by driving an automatic lock cylinder 14 of an automatic lock device 13, and there is a space between the body 1 and the subframe 12 to prevent the body 1 from floating up during driving. A body lock device 15 is attached for this purpose.

Further, a detection switch 16 is fixed to the side surface of the sub-frame 12, and a detection plate 17 is fixed to the position corresponding to the detection switch 16 on the body 1, so that when the body 1 is lowered, the detection plate 17 activates the detection switch. This is detected by pressing 16.

FIG. 3 shows a hydraulic circuit diagram, in which the actuators 6.7, 8, 9.14 are operated by switching the control solenoid valves V1 to V5 provided in the hydraulic circuit 18. Along with being made, the flywheel P
Directly connected to the TO and rotated by this drive, each actuator 6.7 degrees 8, 9. 14 is equipped with a hydraulic pump P that supplies pressure oil from a hydraulic oil tank T.

Details of this hydraulic pump P are shown in FIG.

That is, this hydraulic pump P includes a pump body 20, a first control cylinder 21 and a second control cylinder 22 each having a built-in spring 21a that changes the tilt angle of the swash plate 20a of this pump body 20, and a constant flow rate maintenance control valve. 23, a constant pressure maintenance control valve 24, and a fixed flow rate control valve 25.

The constant flow control valve 23 is set to operate when the differential pressure generated before and after the flow control valve 250 reaches ΔP. That is, when the pump body 20 rotates at high speed due to the accelerator being emptied, etc., the discharge amount increases and the pressure difference across the flow rate control valve 25 reaches ΔP, the constant flow rate maintenance control valve 23 changes from the state shown in the figure. It is designed to switch in the right direction.

Then, when the constant flow rate maintenance control valve 23 switches in this way,
This C port and C port communicate with each other, and the constant pressure maintenance control valve 2
Pilot pressure acts on the base side of the second control cylinder 22 through the b port and the C port of No. 4, and this pilot pressure acts on the spring 21a built in the first control cylinder 21.
When overcoming the elastic force of
The discharge amount of 0 decreases until the differential pressure across the flow rate control valve 25 becomes a flow rate equal to or less than ΔP.

When the discharge amount decreases and the differential pressure across the flow rate control valve 250 becomes ΔP or less, the constant flow rate maintenance control valve 23 returns to the state shown in the figure, and the swash plate 20a of the pump body 20 is built into the first control cylinder 21. It is returned clockwise by the elastic force of the spring 21g.

Here, since the flow rate control valve 25 is a fixed throttle, the differential pressure across the flow rate control valve 25 is kept constant at ΔP due to the above action, so that a constant flow rate can be maintained.

The constant pressure maintenance control valve 24 is set to operate when the discharge side pressure reaches the maximum working pressure.

That is, when a sufficient amount of garbage is loaded, the circuit pressure reaches the maximum operating pressure, and the constant pressure maintenance control valve 24 is switched from the state shown in the figure to the right.

Then, when the constant pressure maintenance control valve 24 switches in this way,
This C port and C port communicate with each other, and the second control cylinder 2
Pilot pressure acts on the base side of pump body 20.
The light oblique angle of the swash plate 20a is set to zero, and the discharge amount is set to zero.

In this case, if the load does not decrease, the constant pressure maintenance control valve 2
4 remains in the switched state, the pressure in the circuit is
It is possible to maintain the discharge amount at zero while maintaining the maximum working pressure.

In this state, if the load decreases and the circuit pressure becomes lower than the maximum working pressure, the constant pressure maintenance control valve 24 returns to the state shown in the figure, and the elastic force of the spring 21a of the first control cylinder 21 moves the swash plate 20a to the figure. The state will return to the state shown in .

As described above, since the constant pressure maintenance control valve 24 is incorporated into the hydraulic pump P, a relief valve that is generally used to regulate the maximum working pressure is not provided.

FIG. 1 shows an electrical circuit diagram for controlling the hydraulic circuit.

That is, the main switch 26, the detection switch 16, and the relay coil CR-1 are connected in series, and a changeover switch 27 for switching between loading and unloading is connected to the main switch 26. The switch 27 is connected in parallel to a loading circuit 28, two tailgate lift circuits, a body lowering switch 32 that operates a body raising circuit 30 and a body lowering solenoid 31, and a beam relay coil CR-2. .

The normally open relay contact Cr-1a of the relay coil CR-1 and the normally closed relay contact Cr-2b of the relay coil CR-2 are connected in series between the main switch 26 and the body lowering solenoid 31. That is, the main switch 26, both relay contacts Cr-1a and Cr-2b, and the body lowering solenoid 31 are connected in series.

As a result, when the main switch 26 is on and the changeover switch 27 is in the neutral position, current flows through the relay coil CR-1 and the normally open relay contact Cr -1a closes, thereby actuating the body lowering solenoid 31, and the solenoid valve V2 for the dump cylinder 9 in FIG.
lower. Then, when the changeover switch 26 is switched from the neutral position to the loading or unloading side, the relay coil CR-2
A current flows through C, and this opens the normally closed contact Cr-2a, allowing normal work to be performed.

Next, the operation of the above embodiment will be explained.

Since body 1 is lowered while driving, detection switch 1
6 is in the on (closed) state, and the changeover switch 27 is in the neutral position (normally, the changeover switch 27 is always returned to the neutral position to prevent malfunction, except when loading or discharging operations are performed. ). Therefore, if the main switch 26 is closed in this state, the relay coil CR-1
A current flows through the body lowering solenoid 31, which closes the relay contact Cr-1a. Then, the electromagnetic switching valve V2 for the dump cylinder 9 is switched to the right from the state shown in FIG. 1 acts to prevent it from floating.

At this time, the dump cylinder 9 has completed its descent (locked at the stroke end) and the output circuit is cut off, so the maximum working pressure is instantly reached, and the constant pressure maintenance control valve 24 of the hydraulic pump P is activated. Due to the action, the dump cylinder 9
maintains the lowering completion state at the maximum working pressure, and the hydraulic pump P
The discharge amount becomes zero.

Then, when the changeover switch 27 is switched to the discharge or loading side, electricity flows to the relay fill CR-2, this relay contact Cr-2b opens, and electricity from this circuit no longer flows to the body lowering solenoid 31. Therefore, the dump cylinder 9 returns to the illustrated position and normal loading and unloading operations can be performed.

Note that some garbage collection vehicles are equipped with a hopper charging device 33 at the rear of the tailgate 2, as shown in FIG. That is, this hopper charging device 33 has a pin 34
a hopper 35 rotatably connected to the tailgate 2 via a hopper cylinder 35, and a hopper cylinder 37 whose base end is rotatably supported by the tailgate 2 via a pin 36 and whose distal end is rotatably connected to the hopper 35. The hopper 35 is mainly composed of a hopper 35, and after garbage is thrown into the hopper 35, the hopper is swung upward to throw the garbage into the tailgate 2.

In the case of such a garbage collection vehicle, if the hopper 35 is driven with the hopper 35 tilted and stored, the hopper 35 may open due to wind pressure from the front surface thereof.

Therefore, in the above embodiment, the hopper cylinder 37 has a similar structure.
In other words, by adopting a configuration in which the hopper cylinder 37 is replaced with the dump cylinder 9, the hopper 35 is moved from the hopper cylinder 37 during traveling.
The hopper 35 is fixed by the strong holding force of the wind pressure.
It is possible to prevent it from opening.

FIGS. 6 and 7 show other embodiments, and the differences from the above embodiments are as follows.

That is, in this embodiment, a relief valve 38 is provided in the hydraulic circuit 18, and between the electromagnetic switching valve V2 for the dump cylinder 9 and the electromagnetic switching valve V3 for the rotary plate hydraulic motor 6, and the hydraulic pump A pilot pipe 39 is arranged between P' and P'. Then, the pilot pressure from this pilot pipe 39 is transferred to the constant flow rate maintenance control valve 23.
The constant pressure maintenance control valve 24 is omitted.

In the case of this embodiment, although it is not possible to obtain a holding force at the maximum working pressure, the hydraulic pump P
' can be made zero.

〔Effect of the invention〕

Since the present invention has the above-described configuration, when the main switch is closed when the body is running with the body completely lowered, the discharge amount of the hydraulic pump becomes zero, and this causes a very small driving force that affects the running. At the same time, the body is held in a completely lowered state via the dump cylinder, thereby increasing the locking force and reliably preventing the body from floating up during driving.

Further, by switching the switching valve from the neutral position, the holding force of the body by the dump cylinder can be released, and the influence on the dump truck can be eliminated.

Moreover, the above-mentioned operation can be performed using the existing hydraulic circuit without adding any electromagnetic valves or the like.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, Figure 1 is an electric circuit diagram, Figure 2 is a side view of a garbage collection vehicle, Figure 3 is a hydraulic circuit diagram, and Figure 4 is a hydraulic pump. 5 is a side view showing the main parts of another example of the garbage collection vehicle, FIGS. 6 and 7 show other embodiments, and FIG. 6 is a diagram equivalent to FIG. 3. , FIG. 7 is a diagram corresponding to FIG. 4. DESCRIPTION OF SYMBOLS 1...Body, 2...Tailgate, 3...Press plate, 4...Rotary plate, 5...Garbage processing device, 6...
Rotating plate hydraulic motor, 7... Pushing plate cylinder, 8...
Tailgate lift cylinder, 9... Dump cylinder, 13... Automatic locking device, 14... Automatic locking cylinder, 15... Body locking device, 16... Detection switch, 20... Pump body , 20a...Swash plate, 21...First control cylinder, 21a...Spring, 22...Second control cylinder, 23...Constant flow rate maintenance control valve, 24...Constant pressure maintenance control Valve, 25... Flow rate control valve, 26... Main switch, 27... Changeover switch, 31... Body lowering solenoid, 33...
...Hopper charging device, 37...Hopper cylinder, 38
...Relief valve, 39...Pilot piping. Applicant's agent Sato-O CR-2B CR-1A Figure 1 Figure 2 Figure Figure

Claims (1)

[Claims] A tailgate containing a built-in garbage disposal device consisting of a rotary plate and a pushing plate is connected to the rear of the body dumped by the dump cylinder and the electromagnetic switching valve for the dump cylinder, and each actuator of the dump cylinder and the garbage disposal device is
In a hydraulic control device for a garbage collection vehicle in which pressure oil is supplied from a hydraulic pump driven via a flywheel PTO, the hydraulic pump is connected to a swash plate with a first control cylinder and a second control cylinder connected in a balance type. In addition, a detection switch is provided to detect that the body is in the lowered position, and when the changeover switch of the garbage disposal device is in the neutral position, the lowering solenoid of the electromagnetic switching valve is activated to lower the body. While holding it in the downward direction,
A circuit control device for a garbage collection vehicle, characterized in that the first and second control cylinders are controlled so that the discharge amount of the hydraulic pump becomes zero.