JPH06824U - Vehicle air conditioner - Google Patents

Abstract

(57) [Summary] [Purpose] In a vehicle air conditioner that uses hydraulic pressure, flushing is automatically performed without leaking hydraulic oil. The vehicle modulator includes an electromagnetic proportional relief valve that causes a pressure difference in hydraulic oil from a hydraulic pump 31b. Then, the heat of the hydraulic oil is radiated from the radiator 35. A filter 34a is arranged downstream of the relief valve. When the hydraulic pump is activated,
The control unit controls the relief valve for a preset time to minimize the relief pressure. That is, the valve opening is maximized. As a result, foreign matter in the hydraulic oil easily passes through the relief valve and is captured by the filter.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle air conditioner, and more particularly to an air conditioner used for a work vehicle such as a rough terrain crane.

[0002]

[Prior art]

 Generally, in the case of a rough terrain crane where the cabin rotates 360 degrees or more, unlike ordinary automobiles, the engine cooling water circulating under the cabin cannot be introduced into the cabin, and this cooling water is used as a heat source for heating. Can not be used as.

A rough terrain crane is equipped with a hydraulic circuit, and an air conditioner used for a rough terrain crane is generally equipped with a heating circuit for heating using a hydraulic circuit and a refrigeration circuit for cooling. .

The hydraulic circuit is provided with a hydraulic oil tank, and the hydraulic oil pumped by the engine pumps up the hydraulic oil in the hydraulic oil tank and supplies it to the hydraulic motor, which drives the hydraulic motor. There is. The heating circuit includes a heating hydraulic pump, and the heating hydraulic pump is connected to the hydraulic motor. A valve mechanism (relief valve) is arranged on the downstream side of the heating hydraulic pump, and this valve mechanism causes a pressure difference in the hydraulic oil supplied from the heating hydraulic pump. Further, a radiator is arranged on the downstream side of the valve mechanism, and this radiator receives operating oil from the valve mechanism and radiates heat from the operating oil. Then, the heat is radiated from this radiator to perform heating.

On the other hand, the refrigeration circuit is equipped with a compressor, and this compressor is connected to the hydraulic motor via, for example, an electromagnetic clutch. An electromagnetic clutch selectively connects the hydraulic motor and the compressor to drive the compressor for cooling.

[0006]

[Problems to be solved by the device]

 By the way, when removing foreign matter from hydraulic oil in conventional vehicle air conditioners, that is, when flushing is performed, the heating circuit is short-circuited in front of the relief valve to prevent the hydraulic oil from passing through the relief valve. It is carried out.

However, when the heating circuit is short-circuited in the preceding stage of the relief valve to perform the flushing, it takes time and trouble to remove and install the relief valve, and the hydraulic oil leaks during the flushing work. There is a problem.

An object of the present invention is to provide a vehicle air conditioner that can automatically perform flushing and does not leak hydraulic oil.

[0009]

[Means for Solving the Problems]

 According to the present invention, a valve mechanism is provided which includes a hydraulic pump, receives a hydraulic oil supplied from the hydraulic pump, and causes a pressure difference in the hydraulic oil, and receives the hydraulic oil from the valve mechanism to generate a heat In a vehicle air conditioner having a radiator that radiates heat, the valve mechanism has a variable pressure difference, a filter is arranged on the downstream side of the valve mechanism, and power is always supplied to the control unit. When initially performing heating or dehumidifying and heating, a vehicle air conditioner is provided which has a control means for controlling the valve mechanism for a predetermined time to minimize the pressure difference of the valve mechanism.

[0010]

[Action]

 In the present invention, when a filter is arranged on the downstream side of the valve mechanism (relief valve) and heating or dehumidifying heating is first performed after power is constantly input to the control unit, the pressure difference due to the valve mechanism is minimized for a predetermined time. I have to. In other words, the opening of the valve mechanism is practically maximized. Therefore, foreign substances contained in the working oil easily pass through the valve mechanism and reach the filter, where they are captured.

[0011]

【Example】

 Hereinafter, the present invention will be described with reference to examples.

Referring to FIG. 1, the illustrated vehicle air conditioner is applied to a rough terrain crane, for example. This vehicle air conditioner has a hydraulic circuit C and a refrigeration circuit D.

The hydraulic circuit C is composed of a hydraulic motor drive circuit C1 and a heating circuit C2. The hydraulic motor drive circuit C1 has a first hydraulic oil tank 30a, a first hydraulic pump 31a and a hydraulic motor 32. The hydraulic oil in the first hydraulic oil tank 30a is pumped up by the first hydraulic pump 31a, and this pumping up is performed. The hydraulic oil thus driven drives the hydraulic motor 32. The first hydraulic pump 31a is driven by the engine of the vehicle. Incidentally, 33 is a safety valve for limiting the pressure to the hydraulic motor 32.

The heating circuit C2 has a second oil-operated tank 30b, a second hydraulic pump 31b, an electromagnetic proportional relief valve 34, a filter 34a, a radiator 35, and an electromagnetic valve 36. When the solenoid valve 36 is open, the hydraulic oil pumped up by the second hydraulic pump 31b opens the solenoid valve 36 and immediately returns to the second oil tank 30b, and the solenoid valve 36 is closed. If it is, the working oil flows to the radiator 35 via the relief valve 34. The second hydraulic pump 31b is connected to the hydraulic motor 32, and is driven by the rotational force of the hydraulic motor 32. Reference numeral 37 is a safety valve that limits the pressure to the relief valve 34 and the solenoid valve 36.

The relief valve 34 causes a pressure difference in the hydraulic oil between the inlet side and the outlet side, and as a result, the hydraulic oil generates heat. This heat generation amount H is obtained by H = 1.41 × Q × ΔP 2.

However, H: calorific value (kcal / h), Q: hydraulic oil flow rate (l / min), ΔP: pressure difference (kgf / cm ² ), 1.41: constant.

Therefore, the amount of heat dissipated by the radiator 35 is proportional to the set pressure of the relief valve 34 (hereinafter referred to as the relief pressure).

On the other hand, the refrigeration circuit D includes a compressor 40, and a condenser 41, a liquid receiver 42, an expansion valve 43, and an evaporator 44 are sequentially connected to the compressor 40, and the condenser 41 and the evaporator 41 are sequentially connected. The unit 44 is configured to forcibly exchange heat with the air by the blower fans 41a and 44a. The compressor 40 is connected to the hydraulic motor 32 via the clutch mechanism 45.

A blower fan 44a, an evaporator 44, and a radiator 35 are installed in the air conditioning air passage 52 inside the cabin. The air conditioning air passage 52 can be switched between a heating air passage and a cooling air passage by a damper (not shown). That is, during heating and dehumidifying and heating, the air in the cabin is sucked through the inlet of the air conditioning air passage 52, blows the air into the cabin through the evaporator 44 and the heat radiator 35, and during cooling, enters the cabin only through the evaporator 44. It is designed to blow out air. A first temperature sensor (not shown in FIG. 1) is provided downstream of the evaporator 44, and a second temperature sensor (not shown in FIG. 1) is provided downstream of the radiator 35. Has been.

Referring also to FIG. 2, the relief valve 34 and the clutch mechanism 45 described above are controlled by the control unit 60. The control unit 60 is connected to the relief valve 34, the clutch mechanism 45, the first temperature sensor 55, and the second temperature sensor 56, and is based on the temperature detected by the first temperature sensor 55 and the preset temperature. Control the clutch mechanism 45. Further, the control unit 60 controls the relief pressure of the relief valve 34 based on the temperature detected by the second temperature sensor 56 and the set temperature. That is, the compressor 40 is turned on / off by issuing a command to connect and disconnect the clutch mechanism 45 during the cooling operation, and the relief pressure of the relief valve 34 is changed from the lower limit value Pmin to the upper limit value Pmax during the heating operation. Control within the range of. Furthermore, during dehumidification heating operation, both cooling and heating operations are performed. An ON time Ta (for example, 20 seconds) and an OFF time Tb (for example, 100 seconds) of the compressor 40 and at least two upper limit values for the relief pressure, for example, Pmax and 1 / 2Pmax are set in the control unit 60. During the dehumidifying heating operation, the compressor 40 is turned on / off every set time Ta and Tb, and in the relief valve 34, the relief pressure becomes Pmax when the compressor 40 is turned on / off, and the compressor 40 is turned on. In case of, it becomes 1 / 2Pmax.

In this embodiment, when the heating operation is performed, the clutch mechanism 45 disconnects the hydraulic motor 32 and the compressor 40, the electromagnetic valve 36 is closed, and the blower fan 44a is driven. . At this time, in the hydraulic motor drive circuit C1, the hydraulic oil flows as shown by the broken arrow in FIG. 1 to drive the hydraulic motor 32, but the compressor 40 is in a stopped state. Further, the hydraulic oil pumped up by the hydraulic pump 31b is sequentially circulated in the order of the relief valve 34 → the radiator 35 → the second oil tank 30b, as shown by the broken line arrow in FIG. Here, when the hydraulic oil passes through the relief valve 34, a pressure difference is generated between the inlet side and the outlet side of the relief valve 34, and the hydraulic oil generates heat. The heat of the hydraulic oil is released by the radiator 35 and heats the air in the air conditioning air passage 52 blown by the blower fan 44a. As a result, the cabin will be heated.

When the cooling operation is performed, the clutch mechanism 45 connects the hydraulic motor 32 and the compressor 40 and drives the blower fans 41a and 44a. As a result, the hydraulic oil pumped up by the first hydraulic pump 31a circulates and drives the hydraulic motor 32, as indicated by the broken line arrow in FIG. The compressor 40 is driven by the rotational force of the hydraulic motor 32, and the refrigerant discharged from the compressor 40 is, as shown by the solid line arrow, condenser 41 → receiver 42 → expansion valve 43 → evaporator 44 → compressor. It circulates in sequence with 40. As a result, the air in the air conditioning circuit 52 is cooled by the evaporator 44, and the inside of the cabin is cooled (at this time, the solenoid valve 36 is opened).

When the dehumidifying and heating operation is performed, the clutch mechanism 45 repeatedly connects the hydraulic motor 32 and the compressor 40 for a predetermined time Ta and releases the predetermined time Tb, closes the solenoid valve 36, and blows the fan 41a ( It operates only when the clutch mechanism 45 is engaged) and drives the blower fan 44a. As a result, the cooling medium discharged from the compressor 40 circulates as in the cooling operation, and the air in the air conditioning air passage 52 is dehumidified and cooled by the evaporator 44. The hydraulic oil pumped up by the second hydraulic pump 31b circulates as in the heating operation, and the radiator 35 heats the air in the air conditioning air passage 52. By the dehumidifying cooling by the evaporator 44 and the heating by the radiator 34, the dehumidifying and warming in the cabin is performed. At this time, the control unit 60 limits the upper limit of the relief pressure P of the relief valve 34 to 1/2 Pmax only while the compressor 40 is ON.

By the way, in the vehicle air conditioner shown in FIG. 1, the filter 34a is arranged between the relief valve 34 and the radiator 35, and here, foreign matter contained in the hydraulic oil is captured. To be done.

When performing the heating operation or the dehumidifying and heating operation, first, the vehicle engine and the first hydraulic pump 31a are connected, and the hydraulic motor 32 is rotationally driven thereby. As a result, the second hydraulic pump 31b is activated (at this time, the solenoid valve 36 is closed). The controller 60 sets the relief pressure of the relief valve 34 to Pmin for a preset time when performing heating or dehumidifying heating for the first time after power is constantly input. That is, as shown in FIG. 3, the opening degree of the relief valve 34 is maximized to increase the gap between the valve body 341 and the valve seat 342. As a result, foreign matter in the hydraulic oil can easily pass through this gap and be captured by the filter. In this way, flushing is automatically performed at the start of operation. The constant power supply is a power supply for actually operating the electromagnetic proportional valve and the damper, that is, a power supply provided separately from the main power supply, and when the main power supply is turned off, the operation mode immediately before turning off is stored. Therefore, it is always used to supply power to the control unit. This constant power is turned on by connecting the power harness to the battery, and turned off by removing the power harness from the battery. Therefore, when servicing a vehicle, the power is always removed from the battery, so the power is always turned off. After maintenance and inspection, the battery is connected to the battery and the power is always turned on. As a result, flushing can be performed automatically and reliably every time a maintenance inspection is performed.

In the above embodiment, the electromagnetic proportional valve was used as the relief valve, but as shown in FIG. 4, the first to Nth relief valves 71 to 7N are arranged in parallel to each other to form a valve mechanism. You may do it. In this case, the first to Nth relief valves 71 to 7N have the first to Nth relief pressures (for example, the first relief pressure is the lowest and the Nth relief pressure is the highest). The control unit 60 may turn on the first relief valve 71 for a predetermined time when receiving the activation signal. That is, the relief valve having the largest valve opening may be selected.

In this case, when the normal operation control is performed (after a predetermined time has elapsed, instead of controlling the valve opening, selection control of the first to Nth relief valves 71 to 7N is performed. Will be done).

[0028]

[Effect of device]

 As described above, in the present invention, when the hydraulic pump is started, the pressure difference due to the valve mechanism is set to the minimum for a predetermined time, that is, the valve opening is set to the maximum. There is an effect that foreign matter in the hydraulic oil can easily pass through the valve mechanism and be caught by the filter. Therefore, flushing can be performed reliably without removing the valve mechanism and without causing hydraulic oil leakage.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining a control system used in the vehicle air conditioner shown in FIG.

FIG. 3 is a diagram showing the relief valve shown in FIG. 1 in a state where the relief pressure is lowest.

FIG. 4 is a view showing another embodiment of the valve mechanism (relief valve).

[Explanation of symbols]

 30a 1st hydraulic oil tank 30b 2nd hydraulic oil tank 31a 1st hydraulic pump 31b 2nd hydraulic pump 32 Hydraulic motor 34 Relief valve 34a Filter 35 Radiator 36 Solenoid valve

Claims (2)

[Scope of utility model registration request] 1. A valve mechanism, which comprises a hydraulic pump, receives a hydraulic oil supplied from the hydraulic pump to generate a pressure difference in the hydraulic oil, and receives the hydraulic oil from the valve mechanism to radiate heat from the hydraulic oil. In the vehicle air conditioner having a radiator, the valve mechanism is variable in pressure difference, a filter is arranged on the downstream side of the valve mechanism, and the power is always input to the control unit first. When performing heating or dehumidifying heating, the vehicle air conditioner is provided with control means for controlling the valve mechanism for a predetermined time to minimize the pressure difference of the valve mechanism. 2. The vehicle air conditioner according to claim 1, wherein the valve mechanism includes a plurality of valve portions, the plurality of valve portions having different pressure differences set in advance and connected in parallel with each other. In the case of performing heating or dehumidifying heating from the beginning when power is constantly input to the control unit, the control unit selects the valve unit with the lowest pressure difference from the plurality of valve units for the predetermined time. A vehicle air conditioner characterized by the above.