JP4925099B2 - Air conditioner - Google Patents

Description

  The present invention relates to a heat medium circulation type air conditioner.

  As a work machine that is operated in a factory or in a certain yard, it is possible to supply noise from the outside to prevent noise and to drive the hydraulic pump from the engine by driving the hydraulic circuit drive source from the engine. For example, an electric excavator that operates in a moving manner is used. In this type of electric work machine, unlike a work machine driven by an engine, it does not have a water-cooled cooling device, and therefore cannot supply hot water for heating to the air conditioner unit.

For this reason, conventionally, there is an air conditioner for a working machine in which water in a water tank is boiled with an electric heater and hot air for heating is supplied to an air conditioner unit (see, for example, Patent Document 1).
JP 2002-61230 A (page 4, FIG. 1)

  This prior art requires a large water tank, which requires a large mounting space, is difficult to mount on a small work machine, requires water management, and is not easy to maintain.

  The present invention has been made in view of these points, and an object thereof is to provide a heat medium circulation type air conditioner that is compact and can be easily maintained.

The invention described in claim 1 includes a heat circuit pump driven by an electric motor, a temperature raising relief valve provided in a flow path in which a heat medium is circulated by the heat circuit pump, and a temperature raising relief. A relief release bypass valve connected in parallel to the valve, a heater core for releasing heat from the heating medium heated by the heating relief valve, a temperature sensor for detecting the temperature of the heating medium, open the relief releasing bypass valve when the detected temperature of the heating medium by the temperature sensor becomes equal to the target temperature, and temperature temperature controller closes the bypass valve for a decrease when the relief released lower specified temperature than the target temperature of the heat medium, cooling Compressor fluid pressure for driving the compressor by operating the compressor for the circuit and the heat medium pressure discharged from the pump for the heat circuit And in the circuit between the heat circuit pump and the temperature raising relief valve and in the circuit between the heat circuit pump and the compressor driving fluid pressure motor, and at the time of cooling, a constant flow rate of the heat medium Is provided with a priority valve for supplying the entire flow rate of the heat medium to the relief valve for heating during heating .

  According to a second aspect of the present invention, the heat medium in the air conditioner according to the first aspect uses part of the hydraulic oil for operating the hydraulic actuator that operates the work machine.

  According to a third aspect of the present invention, in the air conditioner according to the first or second aspect, a heat medium tank that has a function of accommodating a heat medium and cooling the heat medium, and a heat medium circulated by a heat circuit pump The temperature controller is provided with a temperature-reduction bypass valve capable of extracting a part of the heat medium into the heat medium tank, and a check valve capable of sucking the heat medium from the heat medium tank to the heat circuit pump. The temperature control bypass valve is controlled to open when the temperature rises to a predetermined temperature.

According to a fourth aspect of the present invention, there is provided the air conditioner according to the third aspect, wherein the heat medium is circulated by a heat circuit pump and is provided in a flow path through which the heat medium is circulated, and a small capacity tank having a smaller capacity than the heat medium tank. A circulation pump that circulates the heat medium of the tank through the heater core, and the temperature sensor is provided in the small-capacity tank .

According to the first aspect of the present invention, the heating medium is heated by the relief action of the temperature raising relief valve while the heating medium is circulated by the heat circuit pump, and the heated heating medium is used for heating. Since a large water tank as in the hot water system is not required, the air conditioner becomes compact and easy to mount, and maintenance is easy because water management is not required. When the temperature of the heat medium detected by the temperature sensor falls to a specified temperature lower than the target temperature, the temperature controller closes the relief release bypass valve and removes the heat medium from the heat circuit pump via the temperature increase relief valve. Since it circulates, the heat medium is efficiently heated by the relief action, and when the temperature of the heat medium detected by the temperature sensor reaches the target temperature, the temperature controller is connected to the relief valve for raising the temperature for relief release. Since the relief action of the relief valve for raising the temperature is released by opening the bypass valve, the temperature of the heat medium can be appropriately adjusted, and an appropriate amount of heat can be released from the heater core to perform appropriate heating. Further, during cooling, a constant flow rate of the heat medium discharged from the heat circuit pump is supplied to the compressor driving fluid pressure motor by the priority valve to drive the cooling circuit compressor, so that it is discharged from the heat circuit pump. The heat medium pressure can be used effectively not only during heating but also during cooling.

  According to the invention described in claim 2, when the temperature of the hydraulic oil rises due to the operation of the work machine, the relief release bypass valve is automatically opened, and the operating frequency of the temperature raising relief valve is reduced. Compared to the case of heating water, the thermal energy of the hydraulic oil for operating the hydraulic actuator can be used efficiently for heating, and energy saving can be achieved.

  According to the third aspect of the present invention, when the temperature of the heat medium rises to a predetermined temperature, the temperature controller opens the temperature-falling bypass valve to allow a part of the heat medium to escape to the heat medium tank. By causing the heat medium having a temperature to be sucked into the heat circuit pump via the check valve, the temperature of the heat medium that has risen excessively can be efficiently controlled.

According to the fourth aspect of the present invention, the temperature of the heat medium is detected by the temperature sensor provided in the small capacity tank having a smaller capacity than the heat medium tank, and the relief release bypass valve and the temperature drop are detected via the temperature controller. Since the temperature of the heat medium in the small-capacity tank is controlled by the bypass valve, the heat medium in the small-capacity tank can be controlled to a set temperature in a shorter time than when the temperature of the heat medium in the heat-medium tank is controlled, A heat medium having an appropriate temperature can be quickly supplied from the small capacity tank to the heater core by a circulation pump, and the air conditioner can be made compact by the small capacity tank .

Hereinafter, the present invention, indicated underlying technique 1 and 2, the implementation of embodiment shown in FIG. 3 will be described in detail with reference to the work machine shown in FIG.

  FIG. 4 shows an electric hydraulic excavator M as a work machine that does not include a water-cooled cooling device, and an upper swing body S is provided on the lower traveling body T so as to be capable of swinging. Along with C and the front work device F, a power device D that does not use the engine as a power source is provided.

  As shown in FIG. 1, a power device D of the electric excavator M uses a motor 1 that receives electric energy supplied from a battery or an industrial power source as a power source, and the output shaft of the motor 1 is the motor. 1 is connected to a pump drive device 2 that distributes the power of 1 to a plurality of pumps. A plurality of hydraulic shafts such as a traveling hydraulic motor, a turning hydraulic motor, and a front working device hydraulic cylinder are connected to a plurality of output shafts of the pump drive device 2. A plurality of main pumps 3a, 3b supplying hydraulic oil to a hydraulic excavator body hydraulic circuit that operates the actuator, and one of the hydraulic oils for operating the hydraulic actuator supplied to the hydraulic excavator body hydraulic circuit by these main pumps 3a, 3b A heat circuit pump 4 that circulates the part as a heat medium of the heat circuit H is connected. The heat circuit pump 4 can be supplied with hydraulic oil as a heat medium from a main tank 5 as a heat medium tank.

  The heat circuit H is disposed in parallel with the temperature raising relief valve 8 for raising the temperature of the hydraulic oil as a heat medium in the flow path of the discharge line 4d of the heat circuit pump 4 and the temperature raising relief valve 8. A relief relief bypass valve 9 is provided, and the temperature raising relief valve 8 and the relief release bypass valve 9 are connected to a mini tank 10 as a small capacity tank having a smaller capacity than the main tank 5. Yes.

  A return line 11a is branched from a line connecting the mini tank 10 and the suction port 4s of the heat circuit pump 4, and in this return line 11a, a temperature lowering bypass capable of taking hydraulic oil into the main tank 5 is branched. A valve 11 is provided. In addition, a suction line 12a having a check valve 12 that enables suction of hydraulic oil from the main tank 5 to the suction port 4s of the heat circuit pump 4 is provided.

  In the heating circuit A, the suction port of the circulation pump 14 driven by the electric motor 13 is connected to the mini tank 10, and the discharge line of the circulation pump 14 is an air conditioner installed in the cab C of the electric excavator M. The unit (hereinafter referred to as “air conditioner unit”) 15 is returned to the mini tank 10 through a heater core 16 for heating. The heater core 16 is a heat exchanger that releases heat from the hydraulic oil heated by the temperature raising relief valve 8 to the outside.

  On the other hand, the cooling circuit B includes a compressor 17 that compresses the refrigerant. The compressor 17 is driven by an electric motor 28 via a clutch 18 and a belt transmission 19.

  Further, the cooling circuit B includes an evaporator 20 for evaporating the refrigerant provided in the heater core 16 of the air conditioner unit 15. The evaporator 20 incorporates an expansion valve (not shown) on the upstream side, and further includes an upstream pipe. A receiver dryer 21 that removes moisture from the refrigerant and a condenser 22 that condenses the refrigerant are installed in the road.

  The condenser 22 is provided in the oil cooler 24 that cools the hydraulic oil in the hydraulic circuit of the hydraulic excavator body, and receives cooling air from a common cooling fan 26 driven by the electric motor 25.

  The oil cooler 24 cools the working oil returned to the main tank 5, and thus the main tank 5 has a function of cooling the working oil as a heat medium.

  The mini tank 10 is provided with a temperature sensor 29 for detecting the temperature of the hydraulic oil (oil temperature). This temperature sensor 29 is connected to the input of the temperature controller 30 and the output of the temperature controller 30 The portion is connected to each solenoid of the relief release bypass valve 9 and the temperature lowering bypass valve 11.

  FIG. 2 shows a block diagram of the temperature controller 30, in which a temperature sensor 29 and a target temperature setter 31 for setting a target temperature are connected to a subtractor 32, and this subtractor 32 is connected to a temperature raising relief valve. 8 is connected to a relief controller 33 that controls the relief release bypass valve 9 provided in parallel with the return valve 34 and a return controller 34 that controls the temperature lowering bypass valve 11 of the return line 11a.

Next, the operation of the base technology shown in FIGS. 1 and 2 will be described.

  Explaining the heating function of the heating circuit A, the hydraulic oil discharged from the heat circuit pump 4 is warmed by the temperature raising relief valve 8 and returned from the mini tank 10 to the suction port 4s of the heat circuit pump 4 again. H, and a part of the hydraulic oil supplied to the hydraulic excavator body hydraulic circuit by the main pumps 3a and 3b is circulated in the heat circuit H by the heat circuit pump 4, and the relief action of the temperature raising relief valve 8 Heated and heated hydraulic oil is supplied to the heater core 16 in the cab C by the circulation pump 14 from the mini tank 10 and used for heating.

  The temperature adjustment of the heat circuit H is performed by calculating the deviation between the signal of the temperature sensor 29 and the signal of the target temperature setter 31 by the subtractor 32 shown in FIG. 2, and the relief release bypass valve by the relief controller 33. 9 control signal is set. The relief controller 33 turns off when the oil temperature reaches the target temperature t1, switches to a state in which the relief release bypass valve 9 is opened, and turns on when the oil temperature falls to the specified temperature t2 lower than the target temperature t1, thereby releasing the relief. The bypass valve 9 is switched to a closed state.

  On the other hand, a control signal for the temperature-falling bypass valve 11 is set by the return controller 34 according to the temperature deviation. That is, the return controller 34 is turned on at a specified temperature t3 higher than the target temperature and switched to a state in which the temperature-falling bypass valve 11 is opened, and turned off at a specified temperature t4 lower than the specified temperature t3 to be turned on. It has a characteristic of switching the valve 11 to a closed state.

  Therefore, when the oil temperature of the heat circuit H is lower than the specified temperature t2, the relief release bypass valve 9 is closed, the oil temperature is raised by the temperature raising relief valve 8, and relief is released when the oil temperature reaches the target temperature t1. The bypass valve 9 is opened and heating by the temperature raising relief valve 8 is stopped.

  On the other hand, at the specified temperature t3 at which the oil temperature exceeds the target temperature, the temperature-falling bypass valve 11 is turned on to release a part of the operating oil of the heat circuit H to the main tank 5 to lower the oil temperature, and the oil reaches the specified temperature t4 When the temperature falls, the temperature-falling bypass valve 11 is turned off, and the temperature-falling bypass valve 11 is closed.

  The hydraulic oil warmed in the heat circuit H in this way is supplied to the heater core 16 of the air conditioner unit 15 by the circulation pump 14 of the heating circuit A and the inside of the cab C is warmed.

  The cooling function of the cooling circuit B will be described. The refrigerant compressed by the compressor 17 is sent to the condenser 22, where it is cooled by the cooling fan 26 and condensed. The refrigerant liquefied by the condensation is stored after the moisture is removed by the receiver dryer 21, and is evaporated by the action of the expansion valve built in the evaporator 20.

  At this time, since the refrigerant absorbs heat from the air around the evaporator 20 as heat of vaporization, the surrounding air is deprived of heat and cooled. This air is supplied into the cab C as cooling air. The refrigerant evaporated by the evaporator 20 is sent to the compressor 17, compressed again, and sent to the condenser 22.

Next, effects of the base technology shown in FIGS. 1 and 2 will be described.

  Heating is performed by the relief action of the temperature raising relief valve 8 while circulating the working oil as a heat medium by the heat circuit pump 4, and the warmed working oil is used for heating. The water tank is not required, the air conditioner becomes compact, and it can be easily mounted on the electric excavator M, and maintenance is easy because water management is unnecessary.

  When the temperature of the hydraulic fluid detected by the temperature sensor 29 falls to a specified temperature t2 lower than the target temperature t1, the temperature controller 30 closes the relief release bypass valve 9, and the heat circuit pump 4 releases the temperature raising relief. Since the hydraulic oil is circulated through the valve 8, the hydraulic oil is efficiently heated by the relief action, and when the temperature of the hydraulic oil detected by the temperature sensor 29 reaches the target temperature t1, the temperature controller 30 raises the relief for raising the temperature. Since the relief release bypass valve 9 connected in parallel to the valve 8 is opened to release the relief action of the temperature raising relief valve 8, the temperature of the hydraulic oil can be adjusted appropriately, and an appropriate amount of heat is sent to the outside from the heater core 16. It can be released for proper heating.

  When the hydraulic oil temperature rises above the target temperature t1 due to the operation of the electric hydraulic excavator M, the relief release bypass valve 9 is automatically opened and the temperature raising relief valve 8 is less frequently operated. Thus, compared with the case of heating water, the thermal energy of the hydraulic oil for operating the hydraulic actuator can be efficiently used for heating, and energy saving can be achieved.

  When the temperature of the hydraulic oil rises to the specified temperature t3, the temperature controller 30 opens the temperature-falling bypass valve 11 so that a part of the hydraulic oil in the heat circuit H is released to the main tank 5 and returned to the main tank 5. Since the hydraulic oil of the main pumps 3a and 3b is cooled by the oil cooler 24, the appropriately cooled hydraulic oil can be sucked into the heat circuit pump 4 through the check valve 12, and has risen excessively. The temperature of the hydraulic oil can be controlled efficiently.

  The temperature of the hydraulic oil is detected by the temperature sensor 29 provided in the mini tank 10 having a smaller capacity than the main tank 5, and the mini tank 10 is detected by the relief release bypass valve 9 and the temperature lowering bypass valve 11 via the temperature controller 30. Therefore, the hydraulic oil in the mini tank 10 can be controlled to a set temperature in a shorter time than the case of controlling the temperature of the hydraulic oil in the main tank 5. Accordingly, the hydraulic oil having an appropriate temperature can be quickly supplied to the heater core 16, and the air conditioner can be made compact by the mini tank 10.

Next, an embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part similar to the premise technique shown by FIG. 1 and FIG.

  As shown in FIG. 3, the output shaft of the electric motor 1 is connected to a pump drive device 2 that distributes the power of the electric motor 1 to a plurality of pumps, and a hydraulic excavator body is connected to the plurality of output shafts of the pump drive device 2. A plurality of main pumps 3a, 3b in the hydraulic circuit and a heat circuit pump 4 are connected, and these pumps suck hydraulic fluid as a heat medium from a main tank 5 as a heat medium tank.

  In the heat circuit H, a priority valve 35 is provided in the discharge line 4 d of the heat circuit pump 4, and an electromagnetic switching valve 36 is provided in the pilot line of the priority valve 35.

  The priority valve 35 communicates the discharge line 4d of the heat circuit pump 4 with a hydraulic motor 37 as a compressor driving fluid pressure motor when the electromagnetic switching valve 36 is on (pilot line shut-off state). When the switching valve 36 is off (pilot line communication state), the discharge line 4d of the heat circuit pump 4 is in parallel with the relief valve 8 for raising the temperature of the hydraulic oil and the relief valve 8 for raising the temperature. Control is performed so as to communicate with the relief release bypass valve 9 connected to. The temperature increasing relief valve 8 and the relief releasing bypass valve 9 are connected to a mini tank 10 as a small capacity tank provided in the heat circuit H.

  A return line 11a is branched from a line connecting the mini tank 10 and the suction port 4s of the heat circuit pump 4, and a temperature-falling bypass valve 11 for releasing the hydraulic oil to the main tank 5 is provided in the return line 11a. It has been. A suction line 12a having a check valve 12 capable of sucking hydraulic oil from the main tank 5 to the suction port 4s of the heat circuit pump 4 is provided.

  In the heating circuit A, a suction port of a circulation pump 14 driven by an electric motor 13 is connected to the mini tank 10, and a discharge line of the circulation pump 14 is an air conditioner installed in a cab C of the electric excavator M. The unit (hereinafter referred to as “air conditioner unit”) 15 is returned to the mini tank 10 via the heater core 16.

  On the other hand, the cooling circuit B includes a compressor 17 that compresses the refrigerant. The compressor 17 is driven by a hydraulic motor 37 via a clutch 18 and a belt transmission 19.

  Further, the cooling circuit B includes an evaporator 20 for evaporating the refrigerant provided in the heater core 16 of the air conditioner unit 15. The evaporator 20 incorporates an expansion valve (not shown) on the upstream side, and further includes an upstream pipe. A receiver dryer 21 that removes moisture from the refrigerant and a condenser 22 that condenses the refrigerant are installed in the road.

  The condenser 22 is provided in the oil cooler 24 that cools the hydraulic oil in the hydraulic circuit of the hydraulic excavator body, and receives cooling air from a common cooling fan 26 driven by the electric motor 25.

  The mini tank 10 is provided with a temperature sensor 29 for detecting the temperature of the hydraulic oil (oil temperature). This temperature sensor 29 is connected to the input of the temperature controller 30 and the output of the temperature controller 30 The portion is connected to each solenoid of the relief release bypass valve 9 and the temperature lowering bypass valve 11. Since the temperature controller 30 has already been described with reference to FIG. 2, the description thereof is omitted here.

  Next, the function and effect of the embodiment shown in FIG. 3 will be described.

  The hydraulic fluid discharged from the heat circuit pump 4 is supplied from the priority valve 35 to the temperature raising relief valve 8 or the hydraulic motor 37 for driving the compressor.

  That is, when the compressor 17 is not driven, the electromagnetic switching valve 36 is turned off and the priority valve 35 is set to the state shown in FIG. 3, so that the total flow rate of the heat circuit pump 4 is increased to the temperature raising relief valve 8 side. On the other hand, when the compressor 17 is driven, the electromagnetic switching valve 36 is turned on and the priority valve 35 is switched to supply a constant flow rate from the heat circuit pump 4 to the hydraulic motor 37 to drive the compressor 17. Then, the remaining flow rate is allowed to flow to the temperature raising relief valve 8 side.

Therefore, during heating, the electromagnetic switching valve 36 is turned off, the entire flow rate of the pressure oil of the heat circuit pump 4 is supplied to the temperature raising relief valve 8 side, and the oil temperature is increased by the temperature raising relief valve 8. Raise. The temperature control method at this time is the same as that of the base technology shown in FIGS.

  On the other hand, during cooling, the electromagnetic switching valve 36 is turned on, a constant flow rate is supplied to the hydraulic motor 37, and the compressor 17 is driven. Note that the cooling circuit B shown in FIG. 3 is the same as the cooling circuit B shown in FIGS. 1 and 2, and thus the description of the cooling function is omitted.

  Since the temperature in the cab C of the electric excavator M is adjusted by mixing cold air and warm air, the relief release bypass valve 9 and the temperature lowering can be performed in the same manner as the oil temperature control during heating even during cooling. The hydraulic oil temperature is adjusted by controlling the bypass valve 11.

Then, according to the embodiment shown in FIG. 3, at the time of cooling, the constant flow rate of the hydraulic oil discharged from the heat circuit pump 4 is supplied to the hydraulic motor 37 for driving the compressor by the priority valve 35. Since the cooling circuit compressor 17 is driven, the hydraulic pressure discharged from the heat circuit pump 4 can be effectively used not only during heating but also during cooling. In addition, although the same effect as the premise technique shown by FIG. 1 and FIG. 2 is also show | played, description of the effect is abbreviate | omitted.

  The present invention is suitable for installing a cooling device and a heating device on an electric excavator M that does not include a water-cooled cooling device as an engine cooling device, but can also be used for an air-conditioning device such as an electric automobile. It is.

It is a circuit diagram which shows the premise technique of the system configuration | structure of the air conditioner which concerns on this invention. It is a block diagram which shows the structure of the temperature controller of an air conditioner same as the above. Is a circuit diagram showing an implementation form of the system configuration of the air conditioning apparatus according to the present invention. It is a side view which shows the working machine carrying an air conditioner same as the above.

M Electric hydraulic excavator as work machine B Cooling circuit 1 Electric motor 4 Pump for heat circuit 5 Main tank as heat medium tank 8 Relief valve for temperature increase 9 Bypass valve for relief release
10 Mini tank as a small capacity tank
11 Bypass valve for cooling
12 Check valve
14 Circulation pump
16 Heater core
17 Compressor
29 Temperature sensor
30 Temperature controller
35 priority valve
37 Hydraulic motor as a fluid pressure motor for compressor drive

Claims (4)

A heat circuit pump driven by an electric motor;
A relief valve for raising temperature provided in a flow path through which a heat medium is circulated by a heat circuit pump;
A relief release bypass valve connected in parallel to the temperature raising relief valve;
A heater core for heating that releases heat to the outside from the heating medium heated by the relief valve for heating;
A temperature sensor for detecting the temperature of the heat medium;
A temperature controller that opens the relief release bypass valve when the temperature of the heat medium detected by the temperature sensor reaches the target temperature, and closes the relief release bypass valve when the temperature of the heat medium falls to a specified temperature lower than the target temperature ;
A compressor for the cooling circuit;
A fluid pressure motor for driving the compressor that operates by the heat medium pressure discharged from the pump for the heat circuit to drive the compressor;
It is installed in the circuit between the heat circuit pump and the temperature raising relief valve and in the circuit between the heat circuit pump and the compressor driving fluid pressure motor. During cooling, a constant flow rate of the heat medium is used for driving the compressor. An air conditioner comprising: a priority valve that supplies the fluid pressure motor to the relief valve for raising the temperature of the heating medium during heating . The air conditioner according to claim 1, wherein a part of hydraulic oil for operating a hydraulic actuator that operates the work machine is used as the heat medium. A heat medium tank having a function of containing the heat medium and cooling the heat medium;
A temperature-decreasing bypass valve capable of extracting a part of the heat medium circulated by the heat circuit pump into the heat medium tank;
A check valve that enables suction of the heat medium from the heat medium tank to the heat circuit pump,
3. The air conditioner according to claim 1, wherein the temperature controller controls to open the temperature-falling bypass valve when the temperature of the heat medium rises to a predetermined temperature. A small-capacity tank provided in a flow path through which the heat medium is circulated by a heat circuit pump and having a smaller capacity than the heat medium tank;
A circulation pump for circulating the heat medium of the small capacity tank through the heater core,
The air conditioner according to claim 3, wherein the temperature sensor is provided in a small-capacity tank .

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