JPH0751932Y2 - Air conditioner for vehicle - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner suitable for vehicles equipped with a hydraulic circuit and a refrigeration circuit, for example, working vehicles such as rough lane cranes.

[0002]

2. Description of the Related Art Generally, in the case of a rough terrain crane in which the cabin rotates 360 ° or more, unlike ordinary automobiles, the engine cooling water circulating under the cabin cannot be introduced into the cabin, The cooling water cannot be used as a heat source for heating. Therefore, the applicant has proposed an air conditioner for cooling and heating such a vehicle as shown in FIG. 4 (Actual Application No. 1-1238).
36).

This vehicle air conditioner comprises a hydraulic circuit A and a refrigeration circuit B, and the hydraulic circuit A comprises a hydraulic motor drive circuit A1 and a heating circuit A2. The hydraulic motor drive circuit A1 includes an oil tank 10 and a first hydraulic pump 1
1a and the hydraulic motor 12, and the hydraulic oil in the oil tank 10 is pumped up by the first hydraulic pump 11a, and the hydraulic motor 12 is driven by the pumped hydraulic oil. still,
A safety valve 13 limits the pressure applied to the hydraulic motor 12.

The heating circuit A2 has an oil tank 10, a second hydraulic pump 11b, a relief valve 14, a radiator 15, and a normally open solenoid valve 16. When the solenoid valve 16 is open, the hydraulic oil pumped up by the second hydraulic pump 11b returns directly to the oil tank 10 via the solenoid valve 16, and the solenoid valve 16 is closed. At this time, the working oil flows to the radiator 15 via the relief valve 14. The hydraulic pumps 11a and 11b are driven by the engine of the vehicle, and the hydraulic oil is also supplied to various hydraulic actuators (not shown). Further, the relief valve 14 causes a pressure difference between the inlet side and the outlet side,
The downstream hydraulic oil is designed to generate heat.

The refrigeration circuit B includes a compressor 20, a condenser 21, and
The liquid receiver 22, the expansion valve 23, and the evaporator 24 are sequentially connected, and the condenser 21 and the evaporator 24 are configured to forcibly exchange heat of air by the blower fans 21a and 24a. The compressor 20 is connected to the hydraulic motor 12 via a clutch mechanism 25. Further, the blower fan 24a is installed in an air conditioning air passage 26 that guides air conditioning air into the cabin.

In this vehicle air conditioner, when the heating operation is performed in the winter, the clutch mechanism 25 disconnects the hydraulic motor 12 from the compressor 20, the solenoid valve 16 is closed, and the blower fan 24a. To drive.

At this time, in the hydraulic motor drive circuit A1, the hydraulic oil flows to drive the hydraulic motor 12 as shown by the broken line arrow in FIG. 4 , but the compressor 20 is in a stopped state. Further, the hydraulic oil pumped up by the second hydraulic pump 11b sequentially circulates in the order of the relief valve 14 → the radiator 15 → the oil tank 10, as shown by the broken line arrow in FIG . Here, when the hydraulic oil passes through the relief valve 14, a pressure difference is generated between the inlet side and the outlet side of the relief valve 14, and the hydraulic oil generates heat. The heat of this hydraulic oil is radiated by the radiator 15 and is blown by the blower fan 24a.
Heat the air inside. As a result, the cabin is heated.

When performing the cooling operation in the summer, the clutch motor 25 connects the hydraulic motor 12 and the compressor 20, and further drives the blower fans 21a and 24a. As a result, the hydraulic oil pumped up by the first hydraulic pump 11a is supplied to the hydraulic motor 12 as shown by the broken line arrow in FIG.
Cycle to drive this. The compressor 20 is driven by the rotational force of the hydraulic motor 12, and the refrigerant discharged from the compressor 20 is condensed from the condenser 21 to the liquid receiver 22 as shown by the solid arrow.
→ The expansion valve 23 → the evaporator 24 → the compressor 20 are circulated in sequence. As a result, the air in the air conditioning air passage 26 is cooled by the evaporator 24, and the cabin is cooled.

When performing dehumidifying heating operation during the rainy season, etc.,
The clutch mechanism 25 connects the hydraulic motor 12 and the compressor 20, closes the electromagnetic valve 14, and drives the blower fans 21a and 24a. As a result, the refrigerant discharged from the compressor 20 circulates as indicated by the solid line arrow as in the cooling operation, and the evaporator 24 dehumidifies and cools the air in the air conditioning air passage 26. Further, the hydraulic oil pumped up by the second hydraulic pump 11b circulates as shown by the broken line arrow as in the heating operation, and the radiator 15 causes the air conditioning air passage 26 to flow.
The air inside is heated. By the dehumidifying cooling by the evaporator 24 and the heating by the radiator 15, the dehumidifying and heating in the cabin is performed.

[0010]

However, since the hydraulic pumps 11a and 11b are driven by the engine of the vehicle, the dehumidifying and heating operation, that is, the relief valve 1 is performed.
4, the hydraulic oil flows, and the hydraulic motor 11a and the compressor 20
When and are connected, there is a problem that an excessive load is generated on the engine and the running performance of the vehicle is significantly deteriorated.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine even when hydraulic oil flows through a relief valve and a hydraulic motor and a compressor are connected. An object of the present invention is to provide a vehicle air conditioner that does not give an excessive load to the vehicle.

[0012]

In order to solve the above problems, the present invention drives a first hydraulic pump that supplies hydraulic oil to a hydraulic motor by an engine of a vehicle and hydraulically drives a second hydraulic pump of a hydraulic circuit. A relief valve that is connected to the motor and that downstream of the second hydraulic pump in the hydraulic circuit sequentially connects a relief valve that causes a pressure difference in the hydraulic oil and a radiator that radiates the heat of the hydraulic oil generated by the pressure difference. Upstream of the valve, switching means for restricting the flow of hydraulic oil to the relief valve is provided, and the switching means is provided in parallel with the second hydraulic pump.
The refrigerant is driven by the hydraulic motor and produces refrigerant in the refrigeration circuit.
In a vehicle air conditioner provided with a clutch mechanism for connecting and disconnecting a compressor for operating and a hydraulic motor, the relief valve is an electromagnetic proportional type capable of arbitrarily changing a relief pressure. when a and operating oil flows into the relief valve said compressor and said hydraulic motor is connected, is provided with a pressure control means for reducing the relief pressure to a predetermined value.

[0013]

According to the vehicle air conditioner of the present invention, the release
When hydraulic oil flows through the valve and the compressor and the hydraulic motor are connected, the upper limit value of the relief pressure is reduced to a predetermined value. That is, the required power of the first hydraulic pump for driving the hydraulic motor is a combination of the load determined by the relief pressure and the power of the compressor, so the relief pressure is limited to a predetermined value. This reduces the power required for the first hydraulic pump and reduces the load on the engine.

[0014]

1 to 3 show one embodiment of the present invention, in which C is a hydraulic circuit and D is a refrigeration circuit.

This hydraulic circuit C is a hydraulic motor drive circuit C.
1 and a heating circuit C2. The hydraulic motor drive circuit C1 includes a first oil tank 30a and a first hydraulic pump 3
1a and a hydraulic motor 32, the hydraulic oil in the first oil tank 30a is pumped up by the first hydraulic pump 31a, and the hydraulic motor 32 is driven by the pumped hydraulic oil. 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 includes a second oil tank 30b, a second hydraulic pump 31b, an electromagnetic proportional relief valve 34,
It has a radiator 35 and a normally open solenoid valve 36 that serves as a switching means. When the solenoid valve 36 is open, the hydraulic oil pumped up by the second hydraulic pump 31b returns directly to the second oil tank 30b via the solenoid valve 36, and the solenoid valve 36 is closed. At this time, the working oil is allowed to flow 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. Incidentally, 37 is a safety valve for limiting the pressure to the relief valve 34.

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), Δ
P: Pressure difference (kgf / cm ² ) 1.41: Constant ΔP = P−P ′ P: Pressure on the inlet side of the relief valve (relief pressure),
P ': Pressure on the outlet side of the relief valve Therefore, the amount of heat generated by the relief valve 34 is proportional to the set pressure of the relief valve 34 (hereinafter referred to as the relief pressure).

In the refrigeration circuit D, as in the conventional example shown in FIG. 4, a compressor 40, a condenser 41, a liquid receiver 42, and an expansion valve 4 are provided.
3, the evaporator 44 is sequentially connected, and the condenser 41 and the evaporator 44 are forcibly exchanged with each other by the blower fans 41a and 44a. Further, the compressor 40 is connected to the hydraulic motor 32 via the second clutch mechanism 45.
Connected to.

FIG. 2 is a schematic configuration diagram showing a state in which the vehicular air conditioner according to this embodiment is mounted on the rough terrain crane. That is, the air conditioning unit 51 is installed in the cabin 50.
Is installed, and the air conditioning air passage 5 in this air conditioning unit 51 is installed.
Blower fan 44a, evaporator 44 and radiator 35
Has been installed. Further, this air conditioning air passage 52 is provided with a damper 53.
Thus, the air passage for heating and the air passage for cooling can be switched. That is, during heating and dehumidifying heating, as shown by the solid arrow, the air in the cabin 50 is sucked in through the intake port 54 of the air conditioning unit 51 and blown out into the cabin 50 through the evaporator 44 and the radiator 35, and during cooling, the dashed arrow. As shown in FIG. 5, the air is blown into the cabin 50 only through the evaporator 44. Incidentally, 55 is a first temperature sensor provided on the downstream side of the evaporator 44, and 56 is a second temperature sensor provided on the downstream side of the radiator 35.

FIG. 3 shows a control system of the relief valve 34. Reference numeral 60 denotes the relief valve 34 and the clutch mechanism 4.
5 is a control unit. The control unit 60 includes a relief valve 34 clutch mechanism 45, a first temperature sensor 55 and a second temperature sensor 55.
Connected to the temperature sensor 56 of the first temperature sensor 55, and controls the clutch mechanism 45 based on the detected temperature of the first temperature sensor 55 and the set temperature input to the operation unit (not shown). Further, the relief pressure of the relief valve 34 is controlled on the basis of the temperature detected by the second temperature sensor 56 and the set temperature input to the operation unit (not shown). That is, during the cooling operation, the command for connecting and disconnecting the clutch mechanism 45 is issued to turn off the O of the compressor 40.
N / OFF is performed, and during heating operation, the relief pressure of the relief valve 34 is controlled within the range of 0 to the upper limit Pmax. Both the cooling operation and the heating operation are performed during the dehumidifying and heating operation. In this case, two upper limit values Pmax and 1 / 2Pmax with respect to the relief pressure are set and the clutch mechanism 45 is released. Is the upper limit Pmax
When the clutch mechanism 45 is engaged, the upper limit value is set to 1 / 2Pmax.

In this embodiment, when the heating operation is performed in winter, the clutch mechanism 45 disconnects the hydraulic motor 32 from 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 line arrow in FIG. 1 to drive the hydraulic motor 32, but the compressor 40 is stopped. . In addition, the hydraulic oil pumped up by the hydraulic pump 31b, as indicated by the broken line arrow in FIG.
It circulates in the order of 4 → radiator 35 → second oil tank 30b.
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 valve 34, and the working 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 interior of the cabin 50 is heated.

When the cooling operation is performed in the summer, the clutch motor 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 indicated by a solid arrow, a condenser 41 → a liquid receiver 42 → an expansion valve 43 → an evaporator 44 → It circulates in sequence with the compressor 40. This causes the air in the air conditioning circuit 52 to move to the evaporator 4
The inside of the cabin 50 is cooled by cooling at 4.
The connection and release of the clutch mechanism 45 at this time is performed by the control unit 6
It is controlled by 0 based on the detected temperature of the first temperature sensor 55 and the set temperature input to the operation unit (not shown).

When performing dehumidifying heating operation during the rainy season, etc.,
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 (only when the clutch mechanism 45 is connected. (Operation) and the blower fan 44a is driven. As a result, the refrigerant discharged from the compressor 40 circulates as indicated by the solid line arrow as in the cooling operation, and the evaporator 44 dehumidifies and cools the air in the air conditioning air passage 52. Further, the hydraulic oil pumped up by the second hydraulic pump 31b circulates as indicated by the broken line arrow as in the heating operation, and the radiator 35 heats the air in the air conditioning air passage 52. Dehumidifying cooling by this evaporator 44 and radiator 3
By heating by 4, the dehumidifying and heating of the cabin 50 is performed. At this time, the relief valve 34 is released.
The upper limit of the pressure is limited to 1/2 Pmax by the control unit 60.

By the way, during the dehumidifying and heating operation, the working oil flows through the relief valve 34 and the hydraulic motor 32 is operated.
And the compressor 40 are connected, the first hydraulic pump 31
The load of a becomes maximum. The first hydraulic pump 31a at this time
The relationship between the required power L and the pressure difference ΔP of the relief valve 34 will be described below.

First, the required power Lp of the second hydraulic pump 31b for driving the heating circuit C2 is expressed by the following equation. Lp = (ΔP × Q) / (450 × ηp) (ps) ηp: Total efficiency Here, when Q and ηp are kept constant, Lp is proportional to ΔP. Therefore, if ΔP is halved, Lp is also halved.

Next, letting Lc be the required power of the compressor 40 that drives the refrigeration circuit D, the required power L of the first hydraulic pump 31a is expressed by the following equation. L = (Lp + Lc) × ηM (ps) ηM: Total efficiency of hydraulic motor Here, if Lc and ηM are kept constant, L changes by Lp × ηM. Therefore, when Lp becomes 1/2, L becomes 1 /
It is reduced by 2 × Lp × ηM. Therefore, the pressure difference is 1 / 2Δ
When Pmax is 1/2 × Lp × η compared to when ΔPmax
The required power of the first hydraulic pump 31a can be reduced by M.

As described above, according to the vehicle air conditioner of the present embodiment, the relief valve 34 is of the electromagnetic proportional type so that the relief pressure can be arbitrarily changed. Since the upper limit value of the relief pressure is limited to, for example, 1/2 of the heating operation during the dehumidifying heating operation in which the maximum load is applied to the hydraulic pump 31a, the required power of the first hydraulic pump 31a is significantly reduced. be able to. Therefore, even during the dehumidifying and heating operation, an excessive load is not applied to the engine of the vehicle, and it is possible to reliably prevent deterioration of the running performance of the vehicle.

[0029]

As described above, according to the vehicle air conditioner of the present invention, the hydraulic pump of the hydraulic pump when the hydraulic oil flows through the relief valve and the hydraulic motor and the compressor are connected to each other. Since the required power can be significantly reduced, it is possible to reliably prevent deterioration of the running performance of the vehicle without applying an excessive load to the engine of the vehicle.

[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 a vehicle air conditioner.

FIG. 4 is a circuit diagram of a vehicle air conditioner showing a conventional example.

[Explanation of symbols]

31a ... 1st hydraulic pump, 31b ... 2nd hydraulic pump, 3
2 ... Hydraulic motor, 34 ... Relief valve, 34a ... Drive motor, 35 ... Radiator, 36 ... Electromagnetic valve, 45 ... Clutch mechanism, 60 ... Control part, C ... Hydraulic circuit, D ... Refrigeration circuit

Claims (1)

[Scope of utility model registration request] 1. A first hydraulic pump for supplying hydraulic oil to a hydraulic motor is driven by an engine of a vehicle, and a second hydraulic pump of a hydraulic circuit is connected to the hydraulic motor so that the second hydraulic pump is downstream of the hydraulic circuit. Is connected sequentially with a relief valve that creates a pressure difference in the hydraulic oil and a radiator that radiates the heat of the hydraulic oil generated by the pressure difference, and restricts the flow of the hydraulic oil to the relief valve upstream of the relief valve. And a switching means for switching between the second hydraulic pump and the second hydraulic pump.
The refrigerant is driven by the hydraulic motor and produces refrigerant in the refrigeration circuit.
In a vehicle air conditioner provided with a clutch mechanism for connecting and disconnecting a compressor for moving and a hydraulic motor, the relief valve is an electromagnetic proportional type capable of arbitrarily changing a relief pressure, and , Working oil flows through the relief valve and is in front of the compressor.
Serial When a hydraulic motor is connected, the vehicle air conditioning apparatus characterized in that a pressure control means for reducing the relief pressure to a predetermined value.