JP2003267037A - Heating apparatus for work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor-driven work machine capable of obtaining high heating performance by making the best use of an engine-driven heating system, and to secure its safety. <P>SOLUTION: Heating is carried out by circulating water through a route wherein the water in a radiator 11 is sent to a sub-tank 27 to heat it there, and is returned to the radiator 11 through the heat exchanger 16 of a heater unit 15 by a pump 14. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for a working machine using an electric motor as a power source.

[0002]

2. Description of the Related Art A hydraulic excavator, for example, generally operates with an engine as a power source, and heating of a driver's cab is also performed by utilizing engine heat.

An outline of a heating system in this engine-driven hydraulic excavator will be described with reference to FIG.

A radiator 1 supplies cooling water to the engine 2, and a hot water circulation line 3 is connected to the radiator 1.

The hot water circulation line 3 is provided with a hot water pump 4 driven by an engine 2 via a transmission mechanism (not shown) and a heat exchanger 6 of a heater unit 5, and the radiator is heated by the heat of the engine and heated. While the water in 1 circulates in this circulation line 3, the heat is dissipated in the heat exchanger 6 and a heating operation is performed. Reference numeral 7 is a warm air fan that constitutes the heater unit 5, and 8 is an electric motor that drives the fan 7 using a battery as a power source.

However, in the case of a hydraulic excavator used in a place where ventilation is poor, such as in a tunnel or a building, or where engine noise is a problem, instead of the engine,
An electric motor driven by a commercial power source or a battery may be mounted as a power source and may be converted into an electric hydraulic excavator.

[0007]

In this case, since engine heat cannot be used for heating, it is necessary to provide a new heat source for heating.

Therefore, conventionally, while leaving the heating system of FIG. 5, an electric heater is separately installed in the operator's cab, and the heat of the electric heater is discharged directly or by a fan into warm air into the operator's cab. I try to get the heating effect.

However, according to this direct heating method, as shown in FIG.
In comparison with the hot water type heating system, the heating efficiency is poor and the heating performance is remarkably deteriorated, and the electric heater has to be installed near the driver in a narrow cab, which is dangerous.

The present invention solves such a problem, and is a heating device for a working machine, which is electrically driven and can obtain high heating performance by utilizing an engine-driven heating system and ensure safety. Is provided.

[0011]

According to a first aspect of the present invention, there is provided a heating tank for containing a liquid serving as a heating heat medium, an electric heater for heating the liquid in the heating tank, a heat exchanger, and A heater unit having a warm air fan and a heating pump driven by an electric motor are provided, and the liquid heated by the electric heater is circulated by the heating pump in a path passing through a heat exchanger of the heater unit. It is configured in.

According to a second aspect of the present invention, in the structure of the first aspect, the working oil in the oil tank is sent to the actuator by the oil pump, and the working oil discharged from the actuator is returned to the oil tank via the oil cooler. The oil cooler is used as a heating tank, and the working oil as a heat medium in the oil cooler is heated by an electric heater, and the working oil is circulated in a path passing through the heat exchanger of the heater unit by the heating pump. It is configured to allow.

According to a third aspect of the present invention, in the configuration of the first or second aspect, a main tank and a sub-tank having a smaller capacity than the main tank are provided as a tank for containing a liquid serving as a heating heat medium. The liquid sent from the main tank to the sub-tank is heated in the sub-tank by an electric heater and circulated in a path passing through the heat exchanger of the heater unit.

According to a fourth aspect of the invention, in the configuration of the third aspect, a first circulation line for returning the liquid heated in the sub tank to the sub tank through the heat exchanger of the heater unit,
A second circulation line for returning at least a part of the heated liquid to the main tank without passing through the heat exchanger,
The second circulation line is provided with a thermo valve that opens when the temperature of the liquid reaches a preset temperature.

According to a fifth aspect of the present invention, in the structure according to any one of the first to fourth aspects, temperature detecting means for detecting the temperature of the heat medium heated by the electric heater is provided, and the temperature of the heat medium is preset. When the temperature is reached, the power supply to the electric heater is stopped based on the signal from the temperature detecting means.

According to the above structure, the liquid in the heating tank is heated, and the liquid is circulated in the path passing through the heat exchanger of the heater unit by the heating pump. Since the same system is used, the same heating performance as the system can be secured.

That is, as compared with the method of directly heating the inside of the driver's cab by the electric heater, a significantly higher heating performance can be obtained and the safety can be secured.

Further, it is possible to use the equipment mounted on the engine-type working machine (use a radiator or an oil cooler as a heating tank, and use the heater unit and heating piping as they are), and by doing so, Since it requires less equipment to be added, it is advantageous in terms of equipment cost and space.

In this case, according to the structures of claims 3 and 4,
Liquid is sent from a large-capacity main tank to a small-capacity sub-tank and heats the liquid in this sub-tank, so the liquid is heated to the required temperature in a shorter time than when a large amount of liquid in the main tank is heated. can do. Moreover, since the excess heat can be stored in the main tank, there is little heat loss.

For this reason, the heating can be started up quickly at the start of the operation of the machine and at the restart of the operation after the interruption, so that the heating performance can be further improved in this respect.

In particular, according to the structure of claim 4, while the liquid temperature is low, the liquid can be made to flow through the first circulation line to quickly raise the temperature in the sub-tank route, so that the rise of heating can be further improved. Further, when the liquid temperature rises to the set value, at least a part of the liquid is returned to the main tank by the second circulation line to be cooled, so that overheating of the entire system can be prevented and the heating temperature can be automatically adjusted.

Further, since the electric heater capacity is small,
Equipment cost and running cost are low.

According to the fifth aspect of the invention, the operation of the electric heater is controlled according to the liquid temperature, and the automatic temperature adjusting action works. Therefore, it is possible to prevent the electric heater and the liquid from being overheated, and suppress unnecessary power consumption. You can

In this case, by combining with the structure of claim 4, the liquid is quickly cooled by the action of returning the liquid to the main tank and the action of stopping the operation of the electric heater, and the effect of preventing overheating can be enhanced.

[0025]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

The first embodiment (see FIG. 1) 11 is a radiator as a heating tank. An electric heater 12 is provided in the radiator 11, and water in the radiator is heated by the electric heater 12.

The radiator 11 includes a pump electric motor 13
A heating pump 14 driven by is connected, and the pump 14 is configured to circulate the water in the radiator 11 through a circulation line 17 which returns to the radiator 11 through a heat exchanger 16 of the heater unit 15. There is. 1
Reference numeral 8 is a warm air fan of the heater unit 15, and 19 is an electric motor as a drive source thereof.

As the heater unit 15, the heater unit of the heating system originally installed in the working machine driven by the engine is used as it is, and the pump 14 is also used as it is by converting the pump of the heating system into the electric motor drive system. can do.

Further, a thermo switch 20 as a temperature detecting means is provided in the radiator 11, and when the water temperature in the radiator rises above a preset temperature (hereinafter, operation stop temperature), the thermo switch 20 is turned on. It is configured so that the electric power to the electric heater 12 is cut off by working.

According to this structure, the water in the radiator 11 heated by the electric heater 12 and heated is circulated in the circulation line 17 by the pump 14, while the heat of the hot water is released into the cab by the heater unit 15.

That is, since the same heating action as that of the hot water heating system originally installed in the engine-driven working machine works, the same heating performance as that of the system, that is, a method of directly heating the inside of the cab by an electric heater is used. By comparison, much higher heating performance can be obtained.

Moreover, since the heat of the electric heater 12 is released into the driver's cab by the heater unit 15, there is no risk of fire or the like as in the case of the direct heating method, and safety can be secured.

Further, the radiator 11 and the heater unit 1
Since the heating equipment, which is equipped with the engine-driven working machine such as No. 5 and the heating pipe, can be used as it is, less equipment needs to be newly added, which is advantageous in terms of equipment cost and space.

Second Embodiment (See FIG. 2) Only differences from the first embodiment will be described. In a hydraulic work machine such as a hydraulic excavator, as shown in FIG.
4, the hydraulic oil discharged from the actuator 24 is cooled by the oil cooler 25 and returned to the oil tank 21.

This structure is adopted as it is even when the working machine is remodeled from the engine-driven type to the electric type, except that the drive source of the oil pump 22 is changed from the engine to the electric motor 26.

In the second embodiment, in the working machine having such a structure, the oil cooler 25 is used as a heating tank.

That is, the electric heater 12 is provided in the oil cooler 25, and the operating oil heated by the electric heater 12 is the circulation line 17 having the heating pump 14 and the heater unit 15 as in the first embodiment. Is configured to circulate through to perform a heating operation.

Also with this configuration, it is possible to obtain high heating performance by utilizing the existing equipment (oil cooler, heater unit and heating piping).

Third Embodiment (see FIG. 3) In both the first and second embodiments, the liquid in the large capacity radiator 11 or the oil cooler 25 as a heating tank is heated and circulated. On the other hand, in the third embodiment, a large-capacity main tank and a smaller-capacity sub-tank are provided as the heating tank, and the liquid in the main tank is heated in the sub-tank and circulated. There is.

Here, the case where the radiator 11 is applied to the hot water heating system of the first embodiment using the radiator 11 as a heating tank is illustrated, but the oil heating system of the second embodiment using the oil cooler 25 as a heating tank is illustrated. The same can be applied to the following.

A sub-tank 27 is provided separately from the radiator 11 as the main tank, and the water sent from the radiator 11 is heated by the electric heater 12 in the sub-tank 27, and the heater unit 15 is circulated by the circulation line 17.
It is configured to circulate on a route that passes through and returns to the radiator 11.

In this case, the capacity of the sub tank 27 is set as a heat storage water capacity commensurate with the heat generating capacity of the electric heater 12 per unit time.

The heat generation capacity is Q, and the heat storage water capacity is A.
Then, both are expressed by the following equations. A = Q / (circulating water temperature-set cold water temperature) x specific heat of water

As described above, since a large amount of water in the radiator 11 is not directly heated, but is dispensed to the sub-tank 27 and heated little by little, the water content is smaller than that in the first and third embodiments. Can be heated to the required temperature in a short time.

Accordingly, heating starts up quickly when the machine starts to operate and when the operation is restarted after interruption, so that the heating performance can be further improved in this respect.

Further, since the capacity of the electric heater 12 can be small, the equipment cost and the running cost can be low.

Fourth Embodiment (See FIG. 4) In the fourth embodiment, in the configuration of the third embodiment, the water discharged from the pump 14 is returned to the sub tank 27 through the heat exchanger 16 as a circulation line. 1 circulation line 2
8 and a second circulation line 29 for returning a part of the water discharged from the pump 14 to the radiator 11 without passing through the heat exchanger 16, and a thermo valve 30 is provided in the second circulation line 29.
Is provided.

The thermo-valve 30 is closed when the water temperature is below a preset temperature (for example, 90 ° C.) as a value that causes an overheated state when the water temperature rises further, and is opened when the water temperature reaches this set temperature. It is set.

In this way, the thermo valve 30 is closed when the water temperature in the sub-tank 27 is below the set temperature, so that the water in the sub-tank 27 passes from the sub-tank 27 through the heater unit 15 by the first circulation line 28.
Cycle on the route back to 7.

Therefore, it is possible to quickly raise the water temperature to the appropriate heating temperature at the time of starting the heating and reduce the heat loss during the heating.

On the other hand, when the water temperature exceeds the set temperature, the thermo valve 30 opens, so that part of the water discharged from the sub tank 27 enters the radiator 11 by the second circulation line 29 and is cooled there and returns to the sub tank 27. It is possible to prevent overheating of water and the heater unit 15 and automatically adjust the heating temperature.

A thermo valve that closes when the temperature exceeds the set temperature is provided at the inlet of the heat exchanger 14 in the first circulation line 28, and the closing action of this thermo valve and the opening of the thermo valve 30 in the second circulation line 29 are performed. By the action, sub tank 2
All the hot water discharged from 7 may be returned to the radiator 11.

Further, in the fourth embodiment, a thermo switch which is turned on / off by the water temperature in the sub tank 27 is provided, and the energization to the electric heater 12 is stopped at the set temperature or higher as in the first to third embodiments. You may do it.

On the other hand, in each of the first to fourth embodiments, the liquid temperature is suitable for heating in order to prevent the cold air from being discharged from the heater unit 15 when the temperature of the liquid as the heat medium is still low at the start of heating. The hot air fan 18 and the pump 14 may be stopped until the temperature reaches a certain temperature, and these operations may be started when the liquid temperature reaches the appropriate heating temperature.

Further, in the above-described embodiment, the radiator 11 or the oil cooler 25 is used as the heating tank in order to utilize the existing equipment of the working machine as much as possible and to make the equipment simple and low cost. Only from the viewpoint of improving the performance, a new electric heating tank may be newly provided.

[0056]

As described above, according to the present invention, an engine-driven working machine that heats a liquid in a heating tank and circulates this liquid through a heat exchanger of a heater unit by a heating pump. Since it uses basically the same method as the hot water heating system of, the heating performance equivalent to that system is secured, and the heating performance is significantly improved compared to the method of directly heating the inside of the cab by an electric heater, and It is possible to ensure safety.

Further, it is possible to use the equipment mounted on the engine-type working machine (use a radiator or an oil cooler as a heating tank, and use the heater unit and heating piping as they are), and by doing so, Since it requires less equipment to be added, it is advantageous in terms of equipment cost and space.

In this case, according to the inventions of claims 3 and 4,
Liquid is sent from a large-capacity main tank to a small-capacity sub-tank and heats the liquid in this sub-tank, so the liquid is heated to the required temperature in a shorter time than when a large amount of liquid in the main tank is heated. can do. Moreover, since the excess heat can be stored in the main tank, there is little heat loss.

For this reason, the start-up of heating at the time of starting the operation of the machine and at the time of restarting the operation after the interruption is quickened, so that the heating performance can be further improved in this respect.

In particular, according to the invention of claim 4, while the liquid temperature is low, the liquid can be made to flow through the first circulation line to quickly raise the temperature in the sub-tank route, so that the rise of heating can be further improved. Further, when the liquid temperature rises to the set value, at least a part of the liquid is returned to the main tank by the second circulation line to be cooled, so that overheating of the entire system can be prevented and the heating temperature can be automatically adjusted.

Furthermore, since the electric heater capacity is small,
Equipment cost and running cost are low.

According to the fifth aspect of the present invention, the operation of the electric heater is controlled according to the liquid temperature, and the automatic temperature adjusting action works. Therefore, it is possible to prevent overheating of the electric heater and the liquid, and suppress unnecessary power consumption. You can

[Brief description of drawings]

FIG. 1 is a diagram showing a heating system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a heating system according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a heating system according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a heating system according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a heating system in an engine-driven working machine.

[Explanation of symbols]

11 Radiator (main tank) as a heating tank 12 Electric heater 14 Heating pump 13 Pump driving electric motor 15 Heater unit 16 Heat exchanger 18 constituting the heater unit 18 Fan 17 Circulation line 20 Thermo switch as temperature detecting means 25 Oil cooler as a heating tank 27 Sub tank 28 as a heating tank 28 Water circulating in the sub tank is returned to the sub tank via the heater unit 1st circulation line 29 Water heated in the sub tank is passed through a heat exchanger. Second circulation line 30 Thermo valve that returns to the main tank without

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hisayuki Ito             Kobe, 3-12-25 Gion, Asanan-ku, Hiroshima-shi             Ruco Construction Machinery Engineering Co., Ltd. (72) Inventor Satoshi Miyaoka             Kobe, 3-12-25 Gion, Asanan-ku, Hiroshima-shi             Ruco Construction Machinery Engineering Co., Ltd. F-term (reference) 2D015 EC01

Claims (5)

[Claims] 1. A heating tank for containing a liquid serving as a heating medium for heating, an electric heater for heating the liquid in the heating tank, a heater unit having a heat exchanger and a hot air fan, and an electric motor. A heating machine driven by the heating machine, wherein the liquid heated by the electric heater is circulated in a path passing through the heat exchanger of the heater unit by the heating pump. Heating system. 2. The hydraulic oil in the oil tank is sent to an actuator by an oil pump, and the hydraulic oil discharged from the actuator is returned to the oil tank via an oil cooler. The oil cooler serves as a heating tank. The heating oil in the oil cooler is heated by an electric heater, and the operating oil is circulated by a heating pump in a path passing through a heat exchanger of the heater unit. The heating device for a working machine according to 1. 3. A main tank as a tank for containing a liquid serving as a heating medium for heating, and a sub-tank having a smaller capacity than this main tank are provided, and liquid sent from the main tank to the sub-tank is stored in the sub-tank. The heating device for a work machine according to claim 1 or 2, wherein the heating device is heated by an electric heater and is circulated in a path passing through a heat exchanger of the heater unit. 4. A first circulation line for returning the liquid heated in the sub tank to the sub tank through the heat exchanger of the heater unit, and at least a part of the heated liquid without passing through the heat exchanger. 4. A working machine according to claim 3, wherein a second circulation line returning to the tank is provided, and a thermo valve which is opened when the temperature of the liquid reaches a preset temperature is provided in the second circulation line. Heating system. 5. A temperature detecting means for detecting the temperature of a heat medium heated by an electric heater is provided, and when the temperature of the heat medium reaches a preset temperature, the electric heat is generated based on a signal from the temperature detecting means. The heating device for a working machine according to any one of claims 1 to 4, wherein the heating device is configured to stop energizing the device.