CN116815586A - Paver and paving control method - Google Patents

Abstract

The invention discloses a paver and a paving control method. The paver includes a main engine, a screed, a boom, a lifting cylinder, a status switching valve and a paving controller. When the paver switches from the paving stop state to the normal paving state, the state switching valve is controlled by the paving controller so that the lifting chamber and the descending chamber of the lifting cylinder are in a pressure-free state. After a set time, the paving The controller controls the status switching valve so that the descending chamber of the lifting cylinder is in a locked state, the lifting chamber is in a no-pressure state or a locked state, and controls the paver to start paving; after the set time 2, the paving controller controls the status switching valve so that The lifting chamber and descending chamber of the lifting cylinder are both in a pressure-free state. This paving control method is helpful to avoid the phenomenon of starting and rising on the road surface and ensure the quality of road construction.

Description

Paver and paving control method

Technical field

The invention relates to a paver and a paver control method, belonging to the technical field of road construction machinery.

Background technique

The paver is a special construction equipment used to pave various grades of highways, municipal roads and other base-stabilized materials and surface asphalt mixed materials. It has a significant impact on the construction quality of the road surface. A paver consists of a main machine, a screed, a boom, and in most cases an automatic leveling system. The main machine is used to provide power and pull the screed forward. The big arm is hinged to the main machine and connected to the screed at the rear. The screed is used to initially compact, smooth and finally shape the pavement material. The main machine generally also includes a leveling cylinder and a lifting cylinder. The leveling cylinder is used to adjust the height of the hinge point between the boom and the main machine, and the lifting cylinder is used to raise or lower the screed.

Pavers usually adopt the floating paving principle, that is, under normal paving conditions, the two chambers of the lifting cylinder are connected and in a pressure-free state (meaning there is no pressure difference relative to atmospheric pressure). It is in a state of equilibrium under the action of forces, etc. The automatic leveling system includes a leveling sensor and a leveling controller. The leveling sensor can detect the height deviation of the screed relative to the leveling reference. The leveling controller receives the height deviation signal detected by the leveling sensor and ultimately controls the height of the screed by controlling the leveling cylinder to ensure Paving thickness and smoothness.

It is well known to those skilled in the art that during the paving process, when the paver is in a paving stop state (the forward speed is 0 but the paver still has a control function) due to waiting for a skip, etc., the road surface is prone to Shutdown indentation and affect the final quality of the road surface. The most commonly used solution in the industry is to lock the lifting chamber of the lifting cylinder when paving is stopped, but this still cannot completely eliminate the stop indentation phenomenon.

Chinese invention patent CN202110858811.5 proposes a method to reduce the stop indentation by applying pressure to the lifting chamber of the lifting cylinder when the paver is in a paving stop state. Further research found that although this method can better eliminate the stop indentation, the pressure exerted by the lifting chamber of the lifting cylinder when the paver is stopped will cause a change in the attitude of the main engine, and this change in the attitude of the main engine will occur when the paver starts again. Paving may cause a starting phenomenon, which is detrimental to the final quality of the pavement.

Contents of the invention

The object of the present invention is to provide a paver and a paving control method. When the paver is switched to the normal paving state, the state of the lifting chamber and the descending chamber of the lifting cylinder is changed through the state switching valve to avoid the starting phenomenon. , which is conducive to improving the final forming quality of the road surface.

In order to achieve the above objects, the technical solutions adopted by the present invention are as follows:

The invention provides a paver, which includes a main engine, a screed, a boom and a lifting cylinder, and also includes a state switching valve and a paving controller;

The state switching valve is used to change the state of the lifting chamber and the descending chamber of the lifting cylinder;

The paving controller is used to control the power of the state switching valve and control the paver to perform paving;

The paving controller is specifically used to:

When switching from the paving stop state to the normal paving state, the state switching valve is controlled so that both the lifting chamber and the descending chamber of the lifting cylinder are in a pressure-free state;

After the set time 1, the control state switching valve causes the descending chamber of the lifting cylinder to be in a locked state, and the lifting chamber to be in a no-pressure state or a locked state, and controls the paver to start paving;

After the set time 2, the control state switching valve makes both the lifting chamber and the descending chamber of the lifting cylinder in a pressure-free state.

Further, the set time is a preset value.

Further, the set time 2 is negatively related to the paving speed.

Further, the second set time is positively related to the time when the paver is in the paving stop state.

Further, the paver also includes an ambient temperature sensor;

The environmental temperature sensor includes an air temperature sensor and a roadbed temperature sensor.

Further, the second setting time is negatively related to the ambient temperature; the ambient temperature is the weighted average of the air temperature value detected by the air temperature sensor and the subgrade temperature detected by the subgrade temperature sensor.

Further, the state switching valve includes state switching valve one and state switching valve two;

The two inlets of the state switching valve one are connected to the oil return tank, and the two outlets are connected to the lifting chamber and the descending chamber of the two lifting cylinders respectively;

The two inlets of the state switching valve 2 are connected to the pressure oil and return oil tanks respectively, and the outlet is connected to the lifting chambers of the two lifting cylinders;

The paver also includes an electrically adjustable power assist valve, which is connected between the state switching valve 2 and the lifting cavity of the lifting cylinder. The electrically adjusted power assist valve is used to adjust the lifting when the paving is stopped. The pressure in the cylinder lift chamber.

Further, the set time is positively related to the pressure of the electrically adjusted booster valve.

The invention also provides a paving control method, including:

Get paver status,

If the paver switches from the paving stop state to the normal paving state, the lifting chamber and the descending chamber of the lifting cylinder are controlled to be in a pressure-free state by turning the state switching valve on and off;

After the set time 1, the control state switching valve causes the descending chamber of the lifting cylinder to be in a locked state, the lifting chamber to be in a no-pressure state or a locked state, and controls the paver to start paving;

After the set time 2, the control state switching valve makes both the lifting chamber and the descending chamber of the lifting cylinder in a pressure-free state.

Further, if the paver is in a paving stop state, the state switching valve is controlled so that the lifting chamber of the lifting cylinder is in a pressure state and the lowering chamber is in a non-pressure state.

The beneficial effects of the present invention are:

The invention provides a paver that changes the state of the lifting chamber and the descending chamber of the lifting cylinder through a state switching valve. When the paver switches from the paving stop state to the normal paving state, the state switching valve is first controlled so that the lifting cylinder Both the lifting chamber and the descending chamber are in a pressure-free state. After the set time, the main machine has returned to the normal paving posture. At this time, the descending chamber of the lifting cylinder is in a locked state, and the lifting chamber is in a pressure-free state or a locked state and controls When the paver starts paving, it can effectively avoid the starting phenomenon. After the set time 2, the screed has passed the cold material area, and the paving controller controls the status switching valve to make the lifting chamber and descending chamber of the lifting cylinder in a pressure-free state, and the screed enters the normal floating paving state. When the paver is in the paving stop state, the control state switching valve makes the lifting chamber and the descending chamber of the lifting cylinder in a pressurized state and a pressure-free state respectively. At this time, the phenomenon of stop indentation can be well avoided.

Description of the drawings

Figure 1 is a schematic diagram of the paver provided by the present invention;

Figure 2 is a hydraulic principle diagram of the paver provided by the present invention.

Detailed ways

The invention is further described below. The following examples are only used to more clearly illustrate the technical solutions of the present invention, but cannot be used to limit the scope of the present invention.

The present invention provides a paver, see Figure 1, which includes a main machine 1, a screed 2, a boom 3, a lifting cylinder 4, a state switching valve and a paving controller 8. The main machine is used to provide power and pull the screed forward. The big arm is hinged to the main machine and connected to the screed at the rear. The screed is used to initially compact, smooth and finally shape the paving material. The lifting cylinder is hinged to the main machine and connected to the rear of the big arm to adjust the height of the screed. The state switching valve is used to change the state of the lifting chamber and lowering chamber of the lifting cylinder, and the paving controller is used to control the state switching valve and the paving function of the paver.

In the present invention, the paving controller is specifically used to:

When the paving is stopped, the state switching valve is controlled so that the lifting chamber of the lifting cylinder is under pressure and the lowering chamber is under pressure. At this time, the phenomenon of shutdown indentation can be better avoided.

When switching from the paving stop state to the normal paving state, the state switching valve is controlled so that both the lifting chamber and the descending chamber of the lifting cylinder are in a pressure-free state;

After the set time 1, the control state switching valve causes the descending chamber of the lifting cylinder to be in a locked state, the lifting chamber to be in a no-pressure state or a locked state, and controls the paver to start paving;

After the set time 2, the control state switching valve makes both the lifting chamber and the descending chamber of the lifting cylinder in a pressure-free state.

It should be noted that in the present invention, the state switching valve may be a single hydraulic valve or a combination of multiple hydraulic valves.

It should be noted that in the present invention, the paving controller can be an additional controller, but it is better to use the existing controller on the paver, so that no cost is increased.

It should be noted that the lifting cylinder usually has one side of the cylinder barrel connected to the main engine and one side of the piston rod connected to the boom. At this time, the lower chamber of the cylinder is the lifting chamber and the upper chamber is the descending chamber. In the present invention, this common method is also adopted. However, the reverse setting is also theoretically possible.

It should be particularly pointed out that one of the lifting chamber and the descending chamber of the lifting cylinder is in a locked state, and the other is in a pressurized state, which can be equivalently regarded as a two-chamber locked state.

It should be pointed out in particular that when the paver enters the paving stop state from the normal paving state, no matter whether the paver adopts a technical solution in which the lifting chamber of the lifting cylinder is in a locked state, or the lifting chamber and the lowering chamber of the lifting cylinder are in a locked state respectively, The posture of the host will change to a certain extent in both the technical solutions in the pressure state and the non-pressure state.

It should be noted that the current paver controller usually has a timing function, so there is usually no need to set a special timer to time the paving stop state time, set time one, and set time two.

In the present invention, the set time 1 can be a fixed value, such as 2s or 3s. Under normal circumstances, this time interval is enough to completely restore the posture of the host.

When the paver is in the paving stop state and waits for the skip for a long time, the asphalt mixture will become cold and hard. When paving is restarted, it is easy to lift the screed and cause a starting phenomenon. At this time, the lifting cylinder will be lowered. The cavity being in a locked state can prevent or reduce the screed from lifting. When the set time 2 has passed and the screed has passed through the cold material area, the lifting chamber and the descending chamber of the lifting cylinder are in a pressure-free state again, that is, the normal floating paving state is restored.

The faster the paving speed, the shorter the time it takes for the screed to pass through the cold material zone, so setting time two can be negatively related to the paving speed, for example, inversely proportional to the relationship.

The longer the paver is in the paving stop state, the colder the asphalt mixture will be. At this time, it is best to set time 2 to be longer to avoid starting to stand up.

The cooling degree of the asphalt mixture is not only related to the paving stop time, but also related to the ambient temperature. The lower the ambient temperature, the colder the asphalt mixture will be in the same period of time. At this time, the setting time 2 is preferably longer. The ambient temperature can specifically include the air temperature and the subgrade temperature. The lower the air temperature or the subgrade temperature, the colder the asphalt mixture will be in the same period of time, and the best setting time is longer.

In one embodiment of the present invention, an ambient temperature sensor 7 is provided on the paver, specifically including an air temperature sensor and a roadbed temperature sensor, which is used to detect the air temperature value and the roadbed temperature value, and makes the set time 2 negatively correlated with the ambient temperature. It is helpful to eliminate or reduce the phenomenon of starting to stand up. Among them, the ambient temperature value is the weighted average of the air temperature value detected by the air temperature sensor and the subgrade temperature detected by the subgrade temperature sensor. The ambient temperature sensor 7 can be installed on the main unit, the screed, or other locations suitable for detecting air temperature values or roadbed temperature values.

Referring to Figure 2, in one embodiment of the present invention, there are two lifting cylinders and two state switching valves. Among them, the state switching valve 51 is a three-position four-way electromagnetic directional valve, and the state switching valve 2 52 is a two-position three-way electromagnetic directional valve. The two inlets of the state switching valve 51 are connected to the T port (that is, connected back to the oil tank), and the two outlets are connected to the lifting chamber and the descending chamber of the two lifting cylinders respectively. The two inlets of state switching valve 2 52 are connected to port P (pressure oil) and port T respectively, and the outlet is connected to the lifting chambers of the two lifting cylinders.

In addition, it also includes an electrically regulated power assist valve 6, which is connected between the state switching valve 2 52 and the lifting chamber of the lifting cylinder. The electrically regulated power assist valve 6 is used to adjust the pressure in the lifting chamber of the lifting cylinder when the paving is stopped.

The paving control method based on this structure is:

In the normal paving state, the paving controller 8 controls the state switching valve one 51 and the state switching valve two 52 to be deactivated, so that the lifting chamber and the descending chamber of the two lifting cylinders 4 are connected to the T port (that is, connected back to the oil tank) In a no-pressure state, the electric adjustment booster valve 6 does not work at this time.

When the paving is stopped, the paving controller 8 controls the upper position of the status switching valve 51 and the status switching valve 2 52 to be energized, so that the descending chambers (upper chambers) of the two lifting cylinders 4 are connected to the T port in a pressure-free state. , the P port (pressure oil) is connected to the lifting chambers (lower chambers) of the two lifting cylinders 4 through the state switching valve 2 52 and the electric adjustment booster valve 6, so that the lifting chambers are in a pressurized state; it should be noted that in this embodiment The upper position and the lower position of the intermediate state switching valve 51 both refer to the upper and lower positions of the state switching valve 51 shown in FIG. 2 .

When the paver switches from the paving stop state to the normal paving state, the paving controller 8 controls the state switching valve 51 and the state switching valve 52 to be deactivated, so that the lifting chamber and the descending chamber of the two lifting cylinders 4 are both Connected to the T port (that is, connected back to the fuel tank) is in a pressure-free state;

After the set time one, the paving controller 8 controls the state switching valve 1 51 to be energized in the lower position and the state switching valve 2 52 to be de-energized, so that the lifting chambers (lower chambers) of the two lifting cylinders 4 are connected to the T port and are in a non-energized state. In the pressure state, the descending chambers (upper chambers) of the two lifting cylinders 4 are in a locked (not connected) state;

After the set time 2, the paving controller 8 controls the state switching valve 51 and the state switching valve 52 to be deactivated, so that the lifting chamber and the descending chamber of the two lifting cylinders 4 are connected to the T port (that is, connected back to the oil tank) Be in a stress-free state.

It should be noted that the electronically adjusted power assist valve is preferably an electrically proportional fixed value pressure reducing valve. The outlet pressure of the fixed value pressure reducing valve, that is, the pressure in the lifting chamber of the lifting cylinder, can be directly adjusted through current. This solution is relatively simple to implement. . It is also feasible to adjust the pressure of the lifting chamber of the lifting cylinder through an electric proportional relief valve or other hydraulic valve.

It should be noted that the electrically adjusted power assist valve can be fixed pressure or manually adjusted or electrically adjusted.

It should be noted that the setting time one can also be positively related to the pressure of the electronically adjusted power assist valve. For example, it can be linearly related or proportional. For example, when the pressure of the electronically adjusted power assist valve reaches the maximum value, the setting time one also reaches the maximum value. is 3s. When the pressure of the electronically adjusted power assist valve is a certain proportion of the maximum value, the setting time is also a certain proportion of 3s. The greater the pressure of the electronically adjusted booster valve, the greater the change in the posture of the main engine when the paver switches from the paving stop state to the normal paving state, requiring a longer recovery time.

The paving control method based on the above paver is:

Get paver status,

If the paver is in normal paving state, by controlling the state switching valve on and off, the lifting chamber and the descending chamber of the lifting cylinder are controlled to be in a pressure-free state;

If the paver is in a paving stop state, the lifting chamber of the lifting cylinder is controlled to be in a pressurized state and the lowering chamber is in a non-pressure state by controlling the state switching valve on and off;

If the paver switches from the paving stop state to the normal paving state, the lifting chamber and the descending chamber of the lifting cylinder are controlled to be in a pressure-free state by turning the state switching valve on and off;

After the set time 1, the control state switching valve causes the descending chamber of the lifting cylinder to be in a locked state, the lifting chamber to be in a no-pressure state or a locked state, and controls the paver to start paving;

After the set time 2, the control state switching valve makes both the lifting chamber and the descending chamber of the lifting cylinder in a pressure-free state.

The above are only preferred embodiments of the present invention. It should be noted that those of ordinary skill in the art can also make several improvements and modifications without departing from the technical principles of the present invention. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (10)

1. A paver, including a main engine, a screed, a boom and a lifting cylinder, characterized in that it also includes a status switching valve and a paving controller; The state switching valve is used to change the state of the lifting chamber and the descending chamber of the lifting cylinder; The paving controller is used to control the power of the state switching valve and control the paver to perform paving; The paving controller is specifically used to: When switching from the paving stop state to the normal paving state, the state switching valve is controlled so that both the lifting chamber and the descending chamber of the lifting cylinder are in a pressure-free state; After the set time 1, the control state switching valve causes the descending chamber of the lifting cylinder to be in a locked state, and the lifting chamber to be in a no-pressure state or a locked state, and controls the paver to start paving; After the set time 2, the control state switching valve makes both the lifting chamber and the descending chamber of the lifting cylinder in a pressure-free state. 2. A paver according to claim 1, characterized in that the set time is a preset value. 3. A paver according to claim 1, characterized in that the set time 2 is negatively related to the paving speed. 4. A paver according to claim 1, characterized in that the second set time is positively related to the time when the paver is in a paving stop state. 5. A paver according to claim 1, characterized in that the paver further includes an ambient temperature sensor; The environmental temperature sensor includes an air temperature sensor and a roadbed temperature sensor. 6. A paver according to claim 5, characterized in that the set time 2 is negatively related to the ambient temperature; the ambient temperature is the air temperature value detected by the air temperature sensor and the roadbed temperature. Weighted average of the subgrade temperature detected by the sensor. 7. A paver according to any one of claims 1 to 6, characterized in that the state switching valve includes a state switching valve one and a state switching valve two; The two inlets of the state switching valve one are connected to the oil return tank, and the two outlets are connected to the lifting chamber and the descending chamber of the two lifting cylinders respectively; The two inlets of the state switching valve 2 are connected to the pressure oil and return oil tanks respectively, and the outlet is connected to the lifting chambers of the two lifting cylinders; The paver also includes an electrically adjustable power assist valve, which is connected between the state switching valve 2 and the lifting cavity of the lifting cylinder. The electrically adjusted power assist valve is used to adjust the lifting when the paving is stopped. The pressure in the cylinder lift chamber. 8. A paver according to claim 7, characterized in that the set time is positively related to the pressure of the electrically adjusted power assist valve. 9. The paving control method of the paver according to any one of claims 1 to 8, characterized in that it includes: Get paver status, If the paver switches from the paving stop state to the normal paving state, the lifting chamber and the descending chamber of the lifting cylinder are controlled to be in a pressure-free state by turning the state switching valve on and off; After the set time 1, the control state switching valve causes the descending chamber of the lifting cylinder to be in a locked state, the lifting chamber to be in a no-pressure state or a locked state, and controls the paver to start paving; After the set time 2, the control state switching valve makes both the lifting chamber and the descending chamber of the lifting cylinder in a pressure-free state. 10. The paving control method of the paver according to claim 9, characterized in that if the paver is in a paving stop state, the control state switching valve causes the lifting chamber of the lifting cylinder to be in a pressurized state and the lowering chamber to be in a pressurized state. Be in a stress-free state.