JP2021162006A - Coupling cooling system - Google Patents

Abstract

To provide a coupling cooling system that can effectively cool a coupling while restraining an increase in cost of a power device and a decrease in ease of assembly.SOLUTION: A coupling cooling system according to the present invention comprises a power device and a control unit. The power device comprises an engine, a hydraulic pump, a coupling connecting the engine and the hydraulic pump, and a coupling case provided between the engine and the hydraulic pump, and housing the coupling. The coupling case comprises an air intake port communicating with outside air, an air exhaust port for exhausting internal air, and an opening/closing device for opening/closing the air exhaust port. The control unit comprises a heat receiving determination unit for determining the presence or absence of heat reception from the outside of the coupling case, a heat generation determination unit for determining the presence or absence of heat generation in the coupling case, and an opening/closing unit for switching opening/closing of the opening/closing device on the basis of determination results of the heat receiving determination unit and the heat generation determination unit.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coupling cooling system.

In the power unit of construction machinery, a hydraulic pump is rotationally driven by an engine. Specifically, the output shaft of the engine, which is a drive source, and the input shaft of the hydraulic pump are connected by a coupling, for example, via a power divider, and the power of the engine is transmitted. The coupling is covered with a coupling case, and the engine, hydraulic pump and the entire coupling case are covered with a guard.

Since the coupling is housed in this way, it tends to become hot due to the hydraulic oil of the hydraulic pump and the heat from the engine during operation. Therefore, it becomes necessary to use a material having high heat resistance as the material of the coupling, which increases the cost. Further, even if a material having high heat resistance is selected, the coupling may still be damaged by heat or the life of the coupling parts may be shortened.

Therefore, a construction machine provided with a mechanism for cooling the coupling has been proposed (see, for example, Japanese Patent Application Laid-Open No. 2017-206866). In this conventional construction machine, a first partition partition that separates the engine and the coupling and a second partition partition that separates the coupling and the hydraulic pump are provided, and the inside of the guard is divided into an engine chamber and a pump chamber. ing. The coupling will be arranged between the engine chamber and the pump chamber. In addition, each partition wall is provided with a ventilation path.

In this conventional construction machine, when the engine operates, the fan attached to the engine rotates, and a differential pressure is generated between the engine chamber and the pump chamber. Due to this differential pressure, air flows from the engine chamber to the pump chamber. As a result, the air hits the coupling arranged between the engine chamber and the pump chamber as cooling air.

JP-A-2017-206866

In the above-mentioned conventional construction machine, since a new partition wall is required in the guard, the cost tends to increase and the ease of assembling the power unit also decreases. Further, the partition wall may become a noise source due to engine vibration or may be damaged due to resonance. Furthermore, since the structure is such that cooling air always flows through the fan of the engine, it is difficult to prevent damage due to the coupling becoming too cold.

The present invention has been made based on the above circumstances, and is a coupling cooling system capable of effectively cooling a coupling while suppressing an increase in the cost of a power unit and a decrease in ease of assembly. For the purpose of provision.

The coupling cooling system according to one aspect of the present invention includes a power unit for driving a construction machine and a control unit for controlling the power unit, and the power unit includes an engine having an output shaft as a drive source. A coupling case provided between a hydraulic pump having an input shaft driven by the output shaft, a coupling connecting the output shaft and the input shaft, and the engine and the hydraulic pump to store the coupling. The coupling case has an intake port that communicates with the outside air, an exhaust port for discharging the internal air, and an opening / closing device that opens and closes the exhaust port. , The heat receiving determination unit for determining the presence or absence of heat reception from outside the coupling case, the heat generation determination unit for determining the presence or absence of heat generation inside the coupling case, and the determination results of the heat receiving determination unit and the heat generation determination unit. Based on this, it has an opening / closing unit for switching the opening / closing of the opening / closing device.

The coupling cooling system of the present invention can effectively cool the coupling while suppressing an increase in the cost of the power unit and a decrease in ease of assembly.

FIG. 1 is a block diagram showing a configuration of a coupling cooling system according to an aspect of the present invention. FIG. 2 is a flow chart showing a control flow of the control unit of the coupling cooling system of FIG.

[Explanation of Embodiments of the Present Invention]
The coupling cooling system according to one aspect of the present invention includes a power unit for driving a construction machine and a control unit for controlling the power unit, and the power unit includes an engine having an output shaft as a drive source. A coupling case provided between a hydraulic pump having an input shaft driven by the output shaft, a coupling connecting the output shaft and the input shaft, and the engine and the hydraulic pump to store the coupling. The coupling case has an intake port that communicates with the outside air, an exhaust port for discharging the internal air, and an opening / closing device that opens and closes the exhaust port. , The heat receiving determination unit for determining the presence or absence of heat reception from outside the coupling case, the heat generation determination unit for determining the presence or absence of heat generation inside the coupling case, and the determination results of the heat receiving determination unit and the heat generation determination unit. Based on this, it has an opening / closing unit for switching the opening / closing of the opening / closing device.

The coupling cooling system is configured by providing an intake port and an exhaust port in the coupling case of the power unit and providing an opening / closing device in the exhaust port. Since the switchgear can be arranged outside the coupling case, the coupling cooling system can suppress an increase in the cost of the power unit and a decrease in ease of assembly. Further, in the coupling cooling system, the control unit has a heat receiving determination unit and a heat generation determination unit, and the opening / closing unit can open / close the opening / closing device only when cooling is required for the coupling based on the determination result. .. Therefore, it is possible to effectively cool the coupling while preventing the coupling from becoming too cold.

It is preferable that the heat receiving determination unit uses the water temperature and the oil temperature in the power unit for the determination. The heat reception of the coupling is due to the heat supply from the outside such as the engine. Therefore, the amount of heat received by the coupling can be predicted from the water temperature and the oil temperature in the power unit. In addition, the water temperature and oil temperature in the power unit are usually measured and monitored. By using these measurement results, it is not necessary to newly install a measuring device or the like, and the cost increase can be further suppressed.

It is preferable that the heat generation determination unit uses the engine speed for the determination. The coupling may self-heat due to its twist. This phenomenon is likely to occur at a frequency at which engine vibration resonates with the torsional vibration of the coupling. Since the vibration of the engine is related to the engine speed, the calorific value of the coupling can be predicted from the engine speed. Also, engine speed is usually measured and monitored. By using this measurement result, it is not necessary to newly install a measuring device or the like, and the cost increase can be further suppressed.

It is preferable that the control unit further has an efficiency determination unit for determining the efficiency of the engine, and the opening / closing unit further uses the determination result of the efficiency determination unit. Cooling the coupling may reduce engine efficiency. Therefore, if the coupling is cooled when the efficiency of the engine is lowered, the engine efficiency is further lowered and a sufficient engine output may not be obtained. By determining the efficiency of the engine with the efficiency determination unit and opening and closing the opening / closing device in consideration of the determination result at the opening / closing unit, it is possible to prevent the output of the engine from becoming too low.

It is preferable that the efficiency determination unit uses the temperature of the air supplied to the engine for the determination. When the temperature of the air supplied to the engine is high, the engine efficiency tends to decrease. Therefore, by using this air temperature in the efficiency determination unit and closing the switchgear to stop the air circulation when the air temperature is high, it is possible to prevent the engine output from becoming too low.

[Details of Embodiments of the present invention]
Hereinafter, the coupling cooling system according to the embodiment of the present invention will be described with reference to the drawings as appropriate.

The coupling cooling system shown in FIG. 1 includes a power device 1 for driving a construction machine, an air cleaner 2 for sending purified air to the power device 1, and a control unit 3 for controlling the power device 1.

<Power unit>
The power device 1 includes a heat exchanger 11, an engine 12, a hydraulic pump 13, a power divider 14, a coupling 15, and a coupling case 16, which are arranged in a guard 17.

The heat exchanger 11 cools the engine cooling water and the hydraulic oil. The heat exchanger 11 has, for example, a large number of thin tubes having fins, and can be configured to exchange heat between the cooling water or hydraulic oil flowing through the thin tubes and the outside air.

The engine 12 is a power source for construction machinery. The engine 12 has an output shaft 12a as a drive source for the hydraulic pump 13, a fan 12b for generating wind for cooling the heat exchanger 11, and the like. Further, cooling water flows inside the engine 12. This cooling water circulates with the heat exchanger 11 to prevent the engine 12 from overheating.

The hydraulic pump 13 is driven by the engine 12 and discharges hydraulic oil. The hydraulic pump 13 has an input shaft 13a. The input shaft 13a is driven by the output shaft 12a of the engine 12 via the power divider 14.

The power divider 14 makes it possible to connect a plurality of hydraulic pumps 13 to one engine 12, and distributes and transmits the output of the engine 12 to each hydraulic pump 13. The power divider 14 is configured as a gear transmission mechanism including a drive gear driven by an output shaft 12a of the engine 12 and a plurality of driven gears that mesh with the drive gear. Further, the input shaft 13a of each hydraulic pump 13 is configured so that the rotational force of the output shaft 12a of the engine 12 can be obtained from any of the driven gears.

The coupling 15 connects the output shaft 12a of the engine 12 and the input shaft 13a of the hydraulic pump 13. Silicone or natural rubber can be used as the material of the coupling 15, but natural rubber is preferable from the viewpoint of cost. In the coupling cooling system, since the coupling 15 can be effectively cooled, natural rubber having a low heat resistant temperature can be adopted.

The coupling case 16 is provided between the engine 12 and the hydraulic pump 13 to store the coupling 15. The coupling case 16 has an intake port 16a that communicates with the outside air, an exhaust port 16b for discharging the internal air, and a switchgear 16c that opens and closes the exhaust port 16b.

A hose 16d is connected to the intake port 16a, and the other end of the hose 16d is open to the outside of the guard 17. Further, a hose 16e is also connected to the exhaust port 16b, and the other end side of the hose 16e is guided to the outside of the guard 17 and is connected to the upstream side of the air cleaner 2. Since air flows through the air cleaner 2 from the upstream side to the downstream side (from the intake port 2a to the air outlet 2b) as described later, a negative pressure is generated around this air flow. Air is drawn into the air cleaner 2 from the hose 16e connected to the air cleaner 2. When the switchgear 16c is open, the negative pressure causes the air inside the coupling case 16 to be discharged from the exhaust port 16b. When the air is drawn from the exhaust port 16b, the air outside the guard 17 is drawn from the intake port 16a side via the hose 16d. By utilizing the negative pressure of the air cleaner 2 in this way, the outside air can be guided from the intake port 16a to the coupling case 16 as cooling air without providing a special blower.

The diameters of the intake port 16a and the exhaust port 16b are not particularly limited as long as the outside air can be drawn in, but can be 10 mm or more and 20 mm or less. If the diameter is less than the lower limit, the outside air may not be sufficiently drawn in. On the contrary, if the diameter exceeds the upper limit, the wind speed may become too low, and there may be a place inside the coupling case 16 where cooling is insufficient. The same applies to the diameters of the hose 16d connected to the intake port 16a and the hose 16e connected to the exhaust port 16b.

The switchgear 16c is arranged between the exhaust port 16b of the coupling case 16 and the connection position of the air cleaner 2, that is, on the hose 16e. In the coupling cooling system of FIG. 1, although it is arranged outside the guard 17, it may be arranged inside the guard 17. The switchgear 16c is not particularly limited as long as it can turn on / off the air flow in the hose 16e, but for example, a known shut-off valve can be used.

<Air cleaner>
The air cleaner 2 takes in air from the intake port 2a, purifies the air taken in by a filter provided inside, discharges the air from the air blower port 2b, and supplies the air to the engine 12. The air outlet 2b and the engine 12 are connected by a pipe 2c, and the discharged air is guided. Further, a thermometer 2d is provided in the pipe 2c, and the temperature of the air supplied to the engine 12 can be measured.

<Control unit>
The control unit 3 controls the temperature of the coupling 15 by controlling the opening and closing of the opening / closing device 16c. As shown in FIG. 2, the control unit 3 includes a heat receiving determination unit S1, a heat generation determination unit S2, an efficiency determination unit S3, and an opening / closing unit S4.

(Heat receiving judgment unit)
The heat receiving determination unit S1 determines whether or not heat is received from outside the coupling case 16.

The heat received from the outside of the coupling case 16 is dominated by the engine 12, the hydraulic pump 13, and the power divider 14 constituting the power unit 1. These calorific values can be predicted from the temperatures of water and oil passing through the engine 12, the hydraulic pump 13, and the power divider 14. Therefore, the heat receiving determination unit S1 may use the water temperature and the oil temperature in the power unit 1 for the determination. The water temperature and oil temperature in the power unit 1 are usually measured and monitored. By using these measurement results, it is not necessary to newly install a measuring device or the like, and it is possible to suppress an increase in cost by providing the heat receiving determination unit S1.

In the coupling cooling system of FIG. 1, it is preferable to use the temperature of the cooling water flowing through the engine 12 and the oil temperature of the hydraulic oil flowing in the power divider 14 arranged close to the coupling 15. When either temperature is high, the temperature of the coupling case 16 rises. Therefore, as conditions for determining whether or not heat is received, for example, the oil temperature of the power divider 14 is over 80 ° C. and the water temperature of the engine 12 is over 85 ° C. A certain case can be a condition for receiving heat. The above temperatures are examples, and these temperatures are appropriately determined by the material of the coupling 15, the distance between the coupling 15 and the engine 12 or the power divider 14, and the calorific value of the engine 12 or the power divider 14. ..

In addition, other amounts may be used for the determination condition in the heat receiving determination unit S1. Examples of such other amounts include the hydraulic oil temperature of the hydraulic pump 13, the intake manifold temperature in the engine 12, and the like.

When the heat receiving determination unit S1 determines that there is heat reception, the control moves to the efficiency determination unit S3. On the other hand, when the heat receiving determination unit S1 determines that there is no heat reception, the control moves to the heat generation determination unit S2.

(Fever judgment unit)
The heat generation determination unit S2 determines the presence or absence of heat generation, so-called self-heat generation, in the coupling case 16.

The coupling 15 may self-heat due to its twist. This phenomenon is likely to occur at a frequency at which the vibration of the engine 12 resonates with the torsional vibration of the coupling 15. When this condition is met, it is necessary to cool the coupling 15 even when the heat receiving determination unit S1 determines that there is no heat receiving.

Since the vibration of the engine 12 is related to the engine speed, the calorific value of the coupling 15 generated by the resonance can be predicted from the engine speed. Therefore, the heat generation determination unit S2 may use the engine speed for the determination. Engine speed is usually measured and monitored. By using this measurement result, it is not necessary to newly install a measuring device or the like, and it is possible to prevent an increase in cost by providing the heat generation determination unit S2.

When using the engine speed, the condition for determining the presence or absence of heat generation is that the actual engine speed is within the range of the engine speed at which resonance with the coupling 15 occurs, which is calculated in advance. can do.

It should be noted that other amounts can be used for the determination condition in the heat generation determination unit S2. Examples of such other quantities include engine load (torque) and the like. Even if the engine speed is the same, the amount of heat generated may differ depending on the torque. Therefore, it is particularly preferable to determine the presence or absence of self-heating by using the engine speed and the torque together.

When the heat generation determination unit S2 determines that heat is generated, the control moves to the efficiency determination unit S3. On the other hand, when the heat generation determination unit S2 determines that there is no heat generation, the control moves to the opening / closing unit S4.

(Efficiency judgment unit)
The efficiency determination unit S3 determines the efficiency of the engine 12.

Cooling the coupling 15 may reduce the efficiency of the engine 12. Therefore, if the coupling 15 is cooled when the efficiency of the engine 12 is lowered, the efficiency of the engine 12 is further lowered, and there is a possibility that a sufficient engine output cannot be obtained. By determining the efficiency of the engine 12 in the efficiency determination unit S3 and opening / closing the opening / closing device 16c in consideration of the determination result in the opening / closing unit S4, it is possible to prevent the engine output from becoming too low.

The efficiency of the engine 12 can be determined by the temperature of the air supplied to the engine 12 via the pipe 2c of the air cleaner 2. Therefore, the efficiency determination unit S3 may use the temperature of the air supplied to the engine 12, that is, the measurement result of the thermometer 2d, for the determination. By closing the switchgear 16c and stopping the air circulation when the temperature of the air is high, it is possible to prevent the engine output from becoming too low.

As the determination condition in the efficiency determination unit S3, for example, when the temperature of the air supplied to the engine 12 is less than 40 ° C., the condition of high engine efficiency can be set. The above temperature is an example, and this temperature is appropriately determined according to the characteristics of the engine 12.

After the efficiency determination unit S3, the control moves to the opening / closing unit S4. The operation of the opening / closing unit S4 differs depending on the determination result of the efficiency determination unit S3.

(Opening and closing part)
The opening / closing unit S4 switches the opening / closing of the opening / closing device 16c based on the determination results of the heat receiving determination unit S1, the heat generation determination unit S2, and the efficiency determination unit S3.

The opening / closing unit S4 is determined to have high engine efficiency by the efficiency determination unit S3, low engine efficiency by the efficiency determination unit S3, and no heat generation by the heat generation determination unit S2. In some cases, control shifts. The operation of the opening / closing unit S4 will be described separately for these three cases.

When the efficiency determination unit S3 determines that the engine efficiency is high, either the heat reception determination unit S1 determines that the engine is receiving heat or the heat generation determination unit S2 determines that the engine is generating heat from the control flow. Therefore, it is preferable to cool the coupling 15. Since the efficiency determination unit S3 determines that the engine efficiency is high, it is determined that the engine output does not become too low even if the coupling 15 is cooled, so the opening / closing device 16c is opened. By opening the opening / closing device 16c, the outside air circulates in the coupling case 16 and the coupling 15 is cooled.

Even when the efficiency determination unit S3 determines that the engine efficiency is low, either the heat reception determination unit S1 determines that there is heat reception or the heat generation determination unit S2 determines that there is heat generation. However, since the efficiency determination unit S3 determines that the engine efficiency is low, if the coupling 15 is cooled, the engine output may become too low. Therefore, the switchgear 16c is closed. When the switchgear 16c is closed, the circulation of the outside air in the coupling case 16 is stopped, so that the coupling 15 is not cooled and the engine output can be prevented from becoming too low.

When the heat generation determination unit S2 determines that there is no heat generation, the heat reception determination unit S1 determines that there is no heat reception, and the heat generation determination unit S2 determines that there is no heat generation. That is, it can be determined that the coupling 15 is not overheated and it is not necessary to cool the coupling 15. In this case, the coupling 15 is cooled unnecessarily, and the opening / closing device 16c is closed so as not to cause a decrease in engine output, for example.

After the opening / closing unit S4, the control moves to the heat receiving determination unit S1 again. After moving to the heat receiving determination unit S1, the same process is repeated to control the opening and closing of the switchgear 16c. The control unit 3 may perform the above-mentioned control without interruption, but may perform intermittent control by providing a wait period of a certain time until the control unit 3 moves from the opening / closing unit S4 to the heat receiving determination unit S1.

<Advantage>
The coupling cooling system is configured by providing an intake port 16a and an exhaust port 16b in the coupling case 16 of the power unit 1 and providing a switchgear 16c in the exhaust port 16b. Since the switchgear 16c can be arranged outside the coupling case 16, the coupling cooling system can suppress an increase in cost and a decrease in ease of assembly of the power unit 1. Further, in the coupling cooling system, the control unit 3 has a heat receiving determination unit S1 and a heat generation determination unit S2, and only when the coupling 15 needs to be cooled according to the determination result, the opening / closing unit S4 causes the opening / closing device 16c. It can be opened and closed. Therefore, the coupling 15 can be effectively cooled while preventing the coupling 15 from becoming too cold.

[Other Embodiments]
The above embodiment does not limit the configuration of the present invention. Therefore, in the above-described embodiment, the components of each part of the above-described embodiment can be omitted, replaced or added based on the description of the present specification and common general technical knowledge, and all of them are construed as belonging to the scope of the present invention. Should be.

In the above embodiment, the case where the input shafts of a plurality of hydraulic pumps are connected to the output shafts of the engine via a power divider has been described, but the power divider is not an essential component and the input shafts of one hydraulic pump. Is also intended in the present invention when is directly connected to the output shaft of the engine.

In the above embodiment, the case where the air inside the coupling case is discharged by using the negative pressure of the air cleaner has been described, but the method of discharging the air inside the coupling case is not limited to this. For example, negative pressure such as engine exhaust can be used. In addition, dedicated equipment such as a pump for discharging air may be provided.

In the above embodiment, the case where the control unit has the efficiency determination unit has been described, but the efficiency determination unit is not an indispensable component. A coupling cooling system in which the control unit does not have an efficiency determination unit is also an object of the present invention.

In the above embodiment, the case where the control unit first controls the heat receiving determination unit has been described, but it is also possible to control the heat generation determination unit first. Further, the efficiency determination unit may be controlled first. In this way, each control of the control unit does not matter in order.

The coupling cooling system of the present invention can effectively cool the coupling while suppressing an increase in the cost of the power unit and a decrease in ease of assembly.

1 Power unit 11 Heat exchanger 12 Engine 12a Output shaft 12b Fan 13 Hydraulic pump 13a Input shaft 14 Power divider 15 Coupling 16 Coupling case 16a Intake port 16b Exhaust port 16c Opening / closing device 16d, 16e Hose 17 Guard 2 Air cleaner 2a Intake Port 2b Blower 2c Piping 2d Thermometer 3 Control unit

Claims (5)

Power units that drive construction machinery and
Equipped with a control unit that controls the above power unit
The above power unit
An engine with an output shaft as a drive source,
A hydraulic pump having an input shaft driven by the output shaft,
A coupling that connects the output shaft and the input shaft,
It has a coupling case provided between the engine and the hydraulic pump and stores the coupling.
The above coupling case
An air intake that communicates with the outside air,
An exhaust port for exhausting the internal air and
It has an opening and closing device that opens and closes the above exhaust port.
The above control unit
A heat receiving determination unit that determines whether or not heat is received from outside the coupling case,
A heat generation determination unit that determines the presence or absence of heat generation in the coupling case,
A coupling cooling system having an opening / closing unit for switching the opening / closing of the opening / closing device based on the determination result of the heat receiving determination unit and the heat generation determination unit. The coupling cooling system according to claim 1, wherein the heat receiving determination unit uses the water temperature and the oil temperature in the power unit for the determination. The coupling cooling system according to claim 1 or 2, wherein the heat generation determination unit uses the engine speed for the determination. The control unit further includes an efficiency determination unit for determining the efficiency of the engine.
The coupling cooling system according to claim 1, claim 2 or claim 3, wherein the opening / closing unit further uses the determination result of the efficiency determination unit. The coupling cooling system according to claim 4, wherein the efficiency determination unit uses the temperature of the air supplied to the engine for the determination.

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