JPH0510021U - Air conditioner for vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent deterioration of hydraulic fluid and failure of hydraulic equipment due to abnormally high temperatures. An oil temperature sensor 38 for detecting the temperature of hydraulic oil is provided in the second oil tank 30b of the heating circuit C2, and a relief valve 34 is provided when the temperature t detected by the oil temperature sensor 38 exceeds a predetermined upper limit value ta. Lower the relief pressure to lower the temperature of the hydraulic oil.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention is a vehicle equipped with a hydraulic circuit and a refrigeration circuit, such as a rough terrain crane. The present invention relates to a vehicle air conditioner suitable for a work vehicle.

[0002]

[Prior art]

  Generally, in the case of rough terrain crane where the cabin rotates 360 ° or more, Unlike ordinary automobiles, the engine cooling water that circulates under the cabin is introduced into the cabin. It cannot be put in, and this engine cooling water can be used as a heat source for heating. I can't come. Therefore, as an air conditioner for cooling and heating such a vehicle, as shown in FIG. The applicant has proposed what is shown (Japanese Utility Model Application No. 1-123836).

[0003]   This vehicle air conditioner includes a hydraulic circuit A and a refrigeration circuit B, and the hydraulic circuit A It is composed of a hydraulic motor drive circuit A1 and a heating circuit A2. This hydraulic motor The drive circuit A1 has an oil tank 10, a first hydraulic pump 11a and a hydraulic motor 12. Then, the hydraulic oil in the oil tank 10 is pumped up by the first hydraulic pump 11a, The hydraulic oil thus driven drives the hydraulic motor 12. Incidentally, 13 is a hydraulic motor 12. It is a safety valve that limits the pressure to.

[0004]   The heating circuit A2 includes an oil tank 10, a second hydraulic pump 11b, and a relief valve 14. , A radiator 15, and a normally open solenoid valve 16. When the solenoid valve 16 is open First, the hydraulic oil pumped up by the second hydraulic pump 11b is transferred via the solenoid valve 16 to the oil. Returning directly to the tank 10, and when the solenoid valve 16 is closed, the relief valve is opened. The working oil flows to the radiator 15 via the lube 14. In addition, each hydraulic The pumps 11a and 11b are driven by the engine of the vehicle, and various hydraulic actuations (not shown) are performed. Hydraulic oil is also made to flow to the user. Also, the relief valve 14 is an inlet. Pressure difference between the outlet side and the outlet side, causing the hydraulic oil on the downstream side to generate heat. ing.

[0005]   The refrigeration circuit B includes a compressor 20, a condenser 21, a liquid receiver 22, an expansion valve 23, and an evaporator 2. 4 are sequentially connected, and the condenser 21 and the evaporator 24 are respectively provided with the blower fan 21. Air heat is forcibly exchanged by a and 24a. In addition, the compressor 20 Is connected to the hydraulic motor 12 via a clutch mechanism 25. Furthermore, this blast fan The fan 24a is installed in an air conditioning air passage 26 that guides conditioned air into the cabin.

[0006]   In this vehicle air conditioner, the clutch device is used when heating operation is performed in winter. The connection between the hydraulic motor 12 and the compressor 20 is released by the structure 25, and the solenoid valve 1 6 is closed, and the blower fan 24a is further driven.

[0007]   At this time, in the hydraulic motor drive circuit A1, as indicated by the broken line arrow in FIG. The hydraulic oil flows to drive the hydraulic motor 12, but the compressor 20 is stopped. It In addition, the hydraulic oil pumped up by the second hydraulic pump 11b indicates the broken line arrow in FIG. As shown in FIG. 5, the relief valve 14 → radiator 15 → oil tank 10 are sequentially circulated. . Here, when the hydraulic oil passes through the relief valve 14, the inlet side of the relief valve 14 And a pressure difference occurs between the outlet side and the outlet side, and the hydraulic oil generates heat. The heat of this hydraulic oil is applied to the radiator 15 The air in the air-conditioning air passage 26 that is discharged by the blower fan 24a is heated by the blower fan 24a. . As a result, the cabin is heated.

[0008]   When the cooling operation is performed in the summer, the clutch mechanism 25 is used to press the hydraulic motor 12 and the pressure. It connects with the compressor 20 and drives the blower fans 21a and 24a. This The hydraulic oil pumped up by the first hydraulic pump 11a is indicated by the broken line arrow in FIG. As described above, the hydraulic motor 12 is circulated to drive the same. Rotational force of this hydraulic motor 12 The compressor 20 is driven by this, and the refrigerant discharged from the compressor 20 is indicated by the solid arrow. In this order, the condenser 21, the liquid receiver 22, the expansion valve 23, the evaporator 24, and the compressor 20 are sequentially cycled. Circle. As a result, the air in the air conditioning air passage 26 is cooled by the evaporator 24, and The inside of the room is cooled.

[0009]   When performing dehumidifying and heating operation during the rainy season etc., the clutch mechanism 25 is used to operate the hydraulic motor. 12 and the compressor 20 are connected, and the solenoid valve 14 is closed. Drive the motors 21a and 24a. As a result, the refrigerant discharged from the compressor 20 is cooled. As in the case of the cell operation, the air circulates as shown by the solid line arrow, and the inside of the air conditioning air passage 26 is moved by the evaporator 24. The air is dehumidified and cooled. Also, the operation pumped up by the second hydraulic pump 11b. The oil circulates as shown by the broken arrow as in the heating operation, and is conditioned by the radiator 15. The air in the air passage 26 is heated. The dehumidifying cooling by the evaporator 24 and the radiator 15 Dehumidification heating in the cabin will be performed by this heating.

[0010]

[Problems to be solved by the device]

  However, in the conventional vehicle air conditioner, the hydraulic oil is used as the hydraulic equipment for the vehicle. The temperature of the hydraulic oil may reach an abnormally high temperature due to the fact that . If such an abnormally high temperature continues, not only will hydraulic oil deteriorate, but hydraulic equipment There is a problem that it may cause a failure such as.

[0011]   The present invention has been made in view of the above problems, and its purpose is to: For vehicles that can prevent deterioration of hydraulic oil and failure of hydraulic equipment due to abnormally high temperature To provide an air conditioner.

[0012]

[Means for Solving the Problems]

  In order to achieve the above-mentioned object, the present invention provides a hydraulic circuit in a hydraulic circuit according to claim 1. A relief valve that causes a pressure difference in the hydraulic oil and a pressure difference due to the pressure difference are provided on the downstream side of the pump. The radiator that radiates the heat of the generated hydraulic oil is connected in sequence, and the radiator is In the vehicle air conditioner arranged in the air conditioning path, the temperature of the hydraulic oil in the hydraulic circuit The temperature detection means for detecting the temperature And a control means for lowering the relief pressure of the relief valve.

[0013]   Further, in claim 2, the hydraulic oil is pressurized on the downstream side of the hydraulic pump in the hydraulic circuit. Dissipates the heat of the hydraulic oil generated by the relief valve that causes the difference and the pressure difference. Air for vehicles in which radiators are sequentially connected and the radiators are arranged in the air-conditioning air passage. In the harmony device, a temperature detecting means for detecting the temperature of the hydraulic oil in the hydraulic circuit, When the temperature detected by the temperature detecting means exceeds a predetermined value upper limit value, the relief valve A control means for gradually reducing the relief pressure is provided.

[0014]

[Action]

  According to the vehicle air conditioner of claim 1, the temperature of the hydraulic oil in the hydraulic circuit is a predetermined upper limit. If the pressure exceeds the value, the pressure difference of the relief valve will decrease. The amount of heat generated in the oil decreases, and the temperature of the hydraulic oil decreases.

[0015]   According to the vehicle air conditioner of claim 2, it has the effect of claim 1. In addition, since the pressure difference of the relief valve gradually decreases, the air blown out from the radiator Air temperature does not drop sharply.

[0016]

【Example】

  1 to 6 show an embodiment of the present invention, where C is a hydraulic circuit and D is a refrigeration circuit. Is.

[0017]   The hydraulic circuit C is composed of a hydraulic motor drive circuit C1 and a heating circuit C2. There is. The hydraulic motor drive circuit C1 includes a first oil tank 30a and a first hydraulic pump 31a. And a hydraulic motor 32, and the hydraulic oil in the first oil tank 30a is transferred to the first hydraulic pump 3 The hydraulic motor 32 is driven by the pumped hydraulic oil. It The first hydraulic pump 31a is driven by the vehicle engine. . Incidentally, 33 is a safety valve for limiting the pressure to the hydraulic motor 32.

[0018]   The heating circuit C2 includes a second oil tank 30b, a second hydraulic pump 31b, and an electromagnetic proportional type recharger. It has a leaf valve 34, a radiator 35, and a normally open solenoid valve 36 that forms a switching means. . When the solenoid valve 36 is open, it is pumped up by the second hydraulic pump 31b. The operating oil directly returns to the second oil tank 30b via the solenoid valve 36, and the solenoid valve 36 closes. When, the operating oil flows to the radiator 35 via the relief valve 34. It is like this. The second hydraulic pump 31b is connected to the hydraulic motor 32, The hydraulic motor 32 is driven by the rotational force of the hydraulic motor 32. Incidentally, 37 is A safety valve 38 for limiting the pressure to the relief valve 34 is provided in the second oil tank 30b. Oil temperature sensor.

The relief valve 34 causes a pressure difference in the hydraulic oil between the inlet side and the outlet side to heat the hydraulic oil. This calorific value is calculated by the following formula. That is, H = 1.41 × Q × ΔP H: calorific value (kcal / h), Q: hydraulic oil flow rate (l / min), ΔP: pressure difference (kgf / cm ² ) 1.41: constant ΔP = P−P ′ P : Inlet side pressure (relief pressure) of the relief valve, P ': Outlet side pressure of the relief valve Therefore, the amount of heat generated by the relief valve 34 is proportional to the relief pressure of the relief valve 34. .

[0020]   The refrigeration circuit D includes a compressor 40, a condenser 41, and a liquid receiver as in the conventional example shown in FIG. 7. 42, an expansion valve 43, and an evaporator 44 are sequentially connected to each other, and a condenser 41 and an evaporator 4 are provided. 4 is for forcedly exchanging air heat by the blower fans 41a and 44a. ing. The compressor 40 is connected to the hydraulic motor 32 via a clutch mechanism 45. is doing.

[0021]   FIG. 2 shows a rough terrain crane equipped with the vehicle air conditioner according to the present embodiment. It is a schematic block diagram which shows a state. That is, the air conditioning unit 51 is installed in the cabin 50. The air-conditioning air passage 52 in the air-conditioning unit 51 has a blower fan 44a, An evaporator 44 and a radiator 35 are installed. Further, this air conditioning air passage 52 is connected to the damper 5 By 3, it is possible to switch between the air passage for heating and the air passage for cooling. That is, heating and During dehumidification and dehumidification heating, the air in the cabin 50 is fed to the air conditioning unit 5 as indicated by the solid arrow. The air is sucked in through the suction port 54 of the No. 1 and enters the cabin 50 through the evaporator 44 and the radiator 35. At the time of blowing and cooling, the inside of the cabin 50 is passed through only the evaporator 44 as indicated by the broken line arrow. It is supposed to blow out to.

FIG. 3 shows a control system of the relief valve 34, and 60 is a control unit having a microcomputer configuration. The control unit 60 is connected to the oil temperature sensor 38 and the relief valve 34. Further, the control unit 60 sets a predetermined upper limit value ta for the detection value t of the oil temperature sensor 38 (abnormal temperature is ta or more) and an initial value P ₀ (for example, 200 kgf / cm 2) for the relief pressure P of the relief valve 34. ² ) and a minute value (for example, 50 kgf / cm ² ) are set, and the relief valve 34 is controlled according to a program described later.

[0023]   In this embodiment, when the heating operation is performed in the winter, the clutch mechanism 45 is used. While disconnecting the connection between the hydraulic motor 32 and the compressor 40, the solenoid valve 36 is closed, The blower fan 44a is driven.

[0024]   At this time, the hydraulic motor drive circuit C1 is operated as shown by the broken line arrow in FIG. The hydraulic oil flows and the hydraulic motor 32 is driven, but the compressor 40 is stopped. . The hydraulic oil pumped up by the hydraulic pump 31b is indicated by the broken line arrow in FIG. So that the relief valve 34, the radiator 35, and the second oil tank 30b are sequentially circulated. . Here, when the hydraulic oil passes through the relief valve 34, the inlet side of the relief valve 34 And a pressure difference occurs between the outlet side and the outlet side, and the hydraulic oil generates heat. The heat of this hydraulic oil is applied to the radiator 35. The air in the air-conditioning air passage 52 that is discharged by the blower fan 44a is heated by the blower fan 44a. . As a result, the interior of the cabin 50 is heated.

[0025]   When the cooling operation is performed in the summer, the clutch mechanism 45 causes the hydraulic motor 32 and the pressure to be applied. The blower fans 41a and 44a are driven while being connected to the compressor 40. this The hydraulic oil pumped up by the first hydraulic pump 31a is As shown in FIG. 3, the hydraulic motor 32 circulates and drives it. Of this hydraulic motor 32 The compressor 40 is driven by the rotational force, and the refrigerant discharged from the compressor 40 is indicated by a solid arrow. As shown in FIG. 4, the condenser 41 → the liquid receiver 42 → the expansion valve 43 → the evaporator 44 → the compressor 40 And cycle in sequence. As a result, the air in the air conditioning circuit 52 is cooled by the evaporator 44. The inside of the cabin 50 is cooled.

[0026]   When performing dehumidifying and heating operation during the rainy season or the like, the clutch mechanism 45 is used to operate the hydraulic motor. When 32 and the compressor 40 repeatedly connect the predetermined time Ta and release the predetermined time Tb. In fact, the electromagnetic valve 36 is closed and the blower fan 41a (the clutch mechanism 45 is connected (Only when the operation is performed) and the blower fan 44a is driven. This allows the compressor 40 to The discharged refrigerant circulates as shown by the solid arrow as in the cooling operation, and the evaporator 44 At, the air in the air conditioning air passage 52 is dehumidified and cooled. Also, with the second hydraulic pump 31b The pumped hydraulic fluid circulates and is discharged as shown by the broken line arrow as in the heating operation. The air in the air conditioning air passage 52 is heated by the heater 35. Dehumidification by this evaporator 44 Dehumidifying and heating the cabin 50 by cooling and heating by the radiator 34 Becomes

[0027]   Here, the operation of the control unit 60 during heating or dehumidifying heating operation is shown in FIG. This will be described with reference to the chart.

First, the value of the count N is set to an initial value 0, and the relief pressure P of the relief valve 34 is set to an initial value P ₀ (S1, S2). Next, when the temperature of the hydraulic oil rises and the temperature t detected by the oil temperature sensor 38 becomes equal to or higher than the upper limit value ta (S3), 1 is added to the count N (S4), and the relief valve 34 is released. The pressure P is set to a value obtained by subtracting the minute value α from P (S5). Then, after waiting for a time (S6), if the detected temperature t is equal to or higher than the upper limit value ta (S7), the process returns to step S4, 1 is added to the count N, and the pressure difference ΔP is further reduced by a minute value α. To do. If the detected temperature t falls below the upper limit value ta in step S7, the count N is decremented by 1 (S8), and the relief pressure P is set to a value obtained by adding a minute value α to P (S9). Then, after waiting time (S10), if the detected temperature t is below the upper limit value ta (S11), the process returns to step S8, the count N is decremented by 1, and the relief pressure P is further added by a very small value α. The value. If the detected temperature t is equal to or higher than the upper limit value ta in step S11 and the count N is 0 (S12), the process returns to step S3 again. The timing chart shown in FIG. 5 and the graph shown in FIG. 6 show changes with time when the relief pressure ΔP is reduced by three steps by the above operation and then increased by one step. .

[0029]   Thus, according to the vehicle air conditioner of the present embodiment, the second oil of the heating circuit C2 is An oil temperature sensor 38 for detecting the temperature of the hydraulic oil is provided in the tank 30b, and When the temperature t detected by the sensor 38 exceeds a predetermined upper limit value ta, the relief valve 34 Since the relief pressure P of the above is lowered to lower the temperature of the hydraulic oil, abnormally high temperature It is possible to reliably prevent deterioration of hydraulic oil and breakdown of hydraulic equipment due to the above. Also, In this embodiment, when lowering the relief pressure P of the relief valve 34, the relief pressure P is gradually changed. Since it is done in this way, it is possible to prevent a rapid decrease in heating capacity.

[0030]   Incidentally, in the above-mentioned embodiment, the relief pressure is changed by using the electromagnetic relief type relief valve 34. It is shown that P is changed, but instead of this relief valve 34, it is A plurality of relief valves, each set to a different pressure difference, are installed in parallel to The flow may be selectively switched to each relief valve.

[0031]

[Effect of device]

  As described above, according to the vehicle air conditioner of claim 1, at the time of abnormally high temperature, Since the temperature of the hydraulic oil can be lowered quickly, It is possible to reliably prevent breakdown of the pressure device.

[0032]   According to the vehicle air conditioner of claim 2, the effect of claim 1 can be achieved. At the same time, when lowering the relief pressure of the relief valve, the heating capacity is suddenly reduced. Since it can be prevented, the passenger does not feel uncomfortable.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a vehicle air conditioner showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an installation state of a vehicle air conditioner.

FIG. 3 is a block diagram showing a control system of the vehicle air conditioner.

FIG. 4 is a flowchart showing the operation of the control unit.

FIG. 5 is a timing chart showing the operation of the relief valve.
It is

FIG. 6 is a graph showing a temperature change of hydraulic oil.

FIG. 7 is a circuit diagram of a vehicle air conditioner showing a conventional example.

[Explanation of symbols]

31b ... second hydraulic pump, 34 ... relief valve, 35
... radiator, 38 ... oil temperature sensor, 52 ... air conditioning air passage, 60 ...
Controller, C ... Hydraulic circuit

Claims (2)

[Scope of utility model registration request] 1. A release valve for causing a pressure difference in hydraulic oil and a radiator for radiating the heat of the hydraulic oil generated by the pressure difference are sequentially connected to the downstream side of the hydraulic pump in the hydraulic circuit, and the heat radiation is performed. In a vehicle air conditioner in which an air conditioner is arranged in an air-conditioning air passage, temperature detecting means for detecting the temperature of hydraulic oil in the hydraulic circuit, and when the temperature detected by the temperature detecting means exceeds a predetermined upper limit value, A vehicle air conditioner comprising: a control means for lowering the relief pressure of a relief valve. 2. A release valve for causing a pressure difference in the hydraulic oil and a radiator for radiating the heat of the hydraulic oil generated by the pressure difference are sequentially connected to the downstream side of the hydraulic pump in the hydraulic circuit, and the heat radiation is performed. In a vehicle air conditioner in which an air conditioner is arranged in an air-conditioning air passage, temperature detecting means for detecting the temperature of hydraulic oil in the hydraulic circuit, and when the temperature detected by the temperature detecting means exceeds a predetermined upper limit value, An air conditioner for a vehicle, comprising: a control means for gradually reducing a relief pressure of a relief valve.