JP2004347083A - Revolving superstructure type hydraulic vehicle, and cooling method for traveling system thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently cool equipment of a traveling circuit, while shortening length of a drain pipe by directly connecting the drain pipe of a traveling system to a tank. <P>SOLUTION: The drain pipes 32, 33 and 34 of the travelling circuit are directly connected to the oil tank T. On the other hand, during traveling, a working hydraulic pump 3 is driven to circulate the oil between a working circuit 6 and the oil tank T through an oil cooler 8, and the cooled tank oil is supplied to a pump circuit A and a motor circuit B of the traveling circuit by an auxiliary pump 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a hydraulic traveling vehicle such as a wheel crane having an upper turning type and equipped with an HST (Hydrostatic Transmission), and a method of cooling a traveling system thereof.
[0002]
[Prior art]
In an HST vehicle, the hydraulic pump for traveling and the hydraulic motor are connected by a main pipeline to form a closed circuit. Therefore, the replacement of oil in the traveling circuit requires a small amount of water that is insufficient to be replenished by drainage. It becomes.
[0003]
Accordingly, the temperature of the oil in the traveling circuit increases, and the equipment is likely to be overheated. Therefore, it is necessary to cool the traveling circuit.
[0004]
Conventionally, as a technology for cooling equipment in an HST vehicle, a technology is known in which drain oil from a traveling circuit is temporarily stored in a motor case and a pump case to cool a hydraulic motor and a hydraulic pump, and the drain oil having absorbed heat is returned to a tank. (For example, see Patent Document 1).
[0005]
[Patent Document 1]
Published Japanese Utility Model Application No. 5-27421
[Problems to be solved by the invention]
However, when the known technique of cooling the equipment using the drain oil as a cooling medium is diverted to an upper-turn HST vehicle, the following problem occurs.
[0007]
For example, in a rough terrain crane that is a type of a wheel crane, when a lower traveling body is driven by a hydraulic motor with an HST, a hydraulic motor is provided in the lower traveling body, whereas a prime mover, a hydraulic pump, and a tank are Since the main pipeline and the drain pipeline on the hydraulic pump side and the main pipeline and the drain pipeline on the hydraulic motor side are connected to each other by a long pipeline via a swivel joint.
[0008]
Therefore, if the above-described known technology is used as it is, the overall length of the drain line of the traveling system becomes longer and the back pressure increases, so that the back pressure load on the components of the traveling circuit (for example, the seal of the hydraulic motor) increases. May be damaged.
[0009]
On the other hand, if the drain line of the traveling circuit is the shortest, instead of relaying the same line with a motor case and a pump case as in the prior art, instead of connecting the same line directly to an oil tank, the traveling circuit using the drain oil of the liver and kidneys The cooling action of the equipment (motor and pump) is lost.
[0010]
Therefore, the present invention provides an upper turning hydraulic traveling vehicle capable of efficiently cooling the equipment of the traveling circuit while taking a configuration in which the drain pipe of the traveling system is directly connected to the oil tank, and a method of cooling the traveling system. To provide.
[0011]
[Means for Solving the Problems]
The invention (cooling method) according to claim 1 is characterized in that an upper revolving unit is rotatably mounted on a lower traveling unit, and a motor is mounted on the upper revolving unit and both a working hydraulic pump and a traveling hydraulic pump driven by the prime mover during traveling. A working circuit that drives a working hydraulic actuator using the working hydraulic pump as a hydraulic pressure source; an oil tank; and an oil cooler that cools oil returning from the working circuit to the oil tank. A traveling hydraulic motor is provided as a traveling drive source, and the traveling hydraulic motor and the traveling hydraulic pump are connected via a swivel joint to form a traveling circuit of a closed circuit. While the drain oil is directly returned to the oil tank by the drain pipe, the working hydraulic pump is driven to transfer the oil between the working circuit and the oil tank via the oil cooler. In is circulated, is intended to cool the running system and supplied to the travel circuit by an oil supply pump oil in the oil tank.
[0012]
According to a second aspect of the invention (a hydraulic traveling vehicle), an upper revolving structure is rotatably mounted on a lower traveling structure, and a prime mover is mounted on the upper revolving structure, and a traveling hydraulic pump driven by the prime mover during traveling is provided. A working hydraulic pump driven by the prime mover during operation and traveling, a working circuit for driving a working hydraulic actuator using the working hydraulic pump as a hydraulic pressure source, an oil tank, and returning from the working circuit to the oil tank. While an oil cooler for cooling oil is provided, a traveling hydraulic motor as a traveling drive source is provided on the lower traveling body, and the traveling hydraulic motor and the traveling hydraulic pump are connected via a swivel joint. And a drain circuit for returning the drain oil of the traveling circuit directly to the oil tank, and a traveling circuit from the oil tank. Oil supply pumps for replenishing oil are provided, and the oil is circulated between the work circuit and the oil tank via the oil cooler by the work hydraulic pump during traveling, and the oil in the oil tank is supplied to the oil tank. The replenishing pump is configured to replenish the traveling circuit.
[0013]
According to a third aspect of the present invention, in the configuration of the second aspect, a variable displacement type hydraulic pump is used as the working hydraulic pump, and pump control means for controlling the discharge amount of the hydraulic pump to increase when the oil temperature rises. Is provided.
[0014]
According to a fourth aspect of the present invention, in the configuration of the third aspect, the pump control means includes a pump regulator for controlling the tilting of the working hydraulic pump, an electromagnetic proportional valve for sending the operating pressure to the pump regulator, and detecting the oil temperature. And a controller that controls the operation of the electromagnetic proportional valve according to the oil temperature detected by the oil temperature detecting means.
[0015]
According to a fifth aspect of the present invention, in the configuration of any of the second to fourth aspects, a drain oil cooler is provided in the drain line.
[0016]
According to a sixth aspect of the present invention, in the configuration of any one of the second to fifth aspects, the reduction gear cooling pipe for passing a part of the drain oil of the travel circuit through a travel reduction gear that reduces the rotational force of the travel hydraulic motor is provided. It is provided.
[0017]
According to the hydraulic traveling vehicle and the cooling method, since the drain oil in the traveling circuit is directly returned to the oil tank, the total length of the drain pipe can be reduced to a minimum as compared with a known technique in which the drain oil is temporarily stored in a motor case or a pump case. it can. For this reason, the back pressure of the drain pipe can be suppressed, and damage to each part of the device can be prevented.
[0018]
In addition, during traveling, the working hydraulic pump is driven to circulate the oil in the working circuit through the oil cooler, and the cooled oil is replenished to the traveling circuit by the supply pump, thereby lowering the oil temperature in the traveling circuit. Thus, the traveling circuit can be efficiently cooled.
[0019]
Further, since the replenishing oil is cooled using the working hydraulic pump, it is advantageous in terms of cost and energy efficiency as compared with the case where another pump is added.
[0020]
In this case, according to the configuration of claims 3 and 4, in order to increase the discharge amount of the working hydraulic pump when the oil temperature rises, the cooling efficiency by the oil cooler is increased to keep the oil temperature at an appropriate temperature, and the cooling performance of the traveling circuit is improved. It can be kept constant.
[0021]
According to the fifth aspect of the present invention, since the oil cooler is also provided in the drain pipe, the drain oil in the traveling circuit is cooled by the oil cooler for the drain, and the cooling effect by the oil cooler in the working circuit is high. Cooling performance can be obtained.
[0022]
According to the configuration of claim 6, since a part of the drain oil passes through the traveling speed reducer, the traveling speed reducer can be cooled together with the traveling circuit, and overheating thereof can be prevented.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0024]
First embodiment (see FIGS. 1 and 2)
In FIG. 1, reference numeral 1 denotes a prime mover, and both prime working and traveling hydraulic pumps (hereinafter referred to as working pumps and traveling pumps) 3 and 4 are driven by the prime mover 1 via a power distributor 2.
[0025]
The work pump 3 is configured as a variable displacement pump whose tilt is controlled by a work pump regulator 5, and a plurality of work hydraulic actuators (not shown) provided in a work circuit 6 by hydraulic oil from the pump 3. In the case of the rough terrain crane, a boom hoist cylinder, a winch motor, a swing motor, and the like are driven.
[0026]
An oil cooler 8 is provided in a tank line 7 of the working circuit 6, and return oil from an actuator of the working circuit 6 is cooled by the oil cooler 8 and returns to the oil tank T. 9 is a check valve provided in parallel with the oil cooler 8.
[0027]
The work pump regulator 5 is connected to a pilot pressure source 12 via an electromagnetic proportional valve 11 controlled by the controller 10, and based on a signal from the controller 10 according to a tank oil temperature detected by an oil temperature sensor 13. As a result, the secondary pressure of the electromagnetic proportional valve 11 changes, whereby the operation stroke of the work pump regulator 5 changes, and the pump tilt is controlled to be large or small (this point will be described in detail later).
[0028]
On the other hand, the traveling pump 4 is configured as a variable displacement pump of which the displacement is controlled by a bidirectional pump regulator 14 for traveling.
[0029]
A traveling circuit using the traveling pump 4 as a hydraulic power source is constituted by a pump circuit A and a motor circuit B. Each is installed on the lower traveling structure.
[0030]
The pump circuit A includes a traveling pump 4, an electromagnetic switching valve 15 that controls the operation of a traveling pump regulator 14 based on a signal from a controller 10, and a fixed displacement auxiliary pump (oil replenishing) that sucks oil from an oil tank T. Pump 16, a throttle 17 for generating a pressure corresponding to the discharge amount of the auxiliary pump 16, a pressure reducing valve 18 for reducing the pressure generated by the throttle 17 and sending the reduced pressure to the traveling pump regulator 14 via the electromagnetic switching valve 15. A low pressure relief valve 19, overload relief valves 20, 20 for regulating the maximum value of the circuit pressure, and check valves 21, 21 for replenishing a part of the oil from the auxiliary pump 16 to the circuit. ing.
[0031]
The motor circuit B includes a traveling hydraulic motor (hereinafter, referred to as a traveling motor) 22, a flushing valve 23 for discharging surplus oil out of the circuit, a throttle 24 and a flow control valve 25 provided downstream of the flushing valve 23. The two-side motor lines 26 and 27 of the motor circuit B and the two-side main lines 28 and 29 of the pump circuit A are connected via a swivel joint 30 to form a closed circuit.
[0032]
Reference numeral 31 denotes a travel speed reducer that reduces the rotational force of the travel motor 22 and transmits the reduced torque to travel drive wheels (not shown).
[0033]
The pump circuit A has a pump-side drain line 32 into which leak oil from the traveling pump 4 and the relief oil from the low-pressure relief valve 19 flow, and the motor circuit B has an oil leak from the traveling motor 22 and a flushing valve. Motor-side drain pipes 33 into which the discharged oil from 23 flows into are provided, respectively, and these two drain pipes 32, 33 are connected to the tank T via a swivel joint 30 and a combined drain pipe 34.
[0034]
As described above, since the drain pipes 32, 33, and 34 are connected to the tank T by the shortest path, the pipe length can be minimized. Therefore, even in an upper turning type vehicle in which the length of the drain pipe is long, the back pressure generated in the traveling circuit can be suppressed low by the drain pipes 32, 33, and 34. ) Is reduced, and these damages are prevented.
[0035]
In the above configuration, when a shift lever (not shown) is operated, the electromagnetic switching valve 15 is switched and operated by a signal from the controller 10 based on the operation signal, and oil from the auxiliary pump 16 travels via the electromagnetic switching valve 15. It is sent to the pump regulator 14 and the tilt of the traveling pump 4 increases.
[0036]
As a result, the oil discharged from the pump 4 is sent to the motor circuit B, the traveling motor 22 rotates, and the vehicle travels.
[0037]
During this traveling, the oil leaked from the traveling pump 4 and the traveling motor 22, and the oil discharged through the low-pressure relief valve 19 and the flushing valve 23 are drained through the drain lines 32 and 33 and the combined drain line 34. Returned to tank T.
[0038]
On the other hand, at this time, the work circuit 6 is stopped, but the work pump 3 is driven, and the oil discharged from the work pump 3 passes through the work circuit 6 and is cooled by the oil cooler 8 so that the oil tank T and the pump 3 Circulates to
[0039]
The drainage oil from the traveling circuit is cooled by the oil circulation action of the working system, and is then replenished to the traveling circuit by the auxiliary pump 16, so that the traveling is a closed circuit including the traveling pump 4 and the traveling motor 2. The circuits (pump circuit A and motor circuit B) are cooled.
[0040]
That is, while taking a configuration in which the drain pipes 32, 33, and 34 are directly connected to the oil tank T without passing through the pump case or the motor case as in the known technique, the traveling circuit is connected to the low-temperature passage through the oil cooler 8. It can be cooled by oil and kept at an appropriate temperature.
[0041]
In this case, a large amount of oil discharged from the work pump 3 is cooled by the oil cooler 8, so that the tank oil temperature can be efficiently cooled, and thereby the cooling function of the traveling circuit can be efficiently performed.
[0042]
In this embodiment, the cooling operation is controlled according to the tank oil temperature. This will be described with reference to the flowchart of FIG.
[0043]
In the controller 10, a reference value as a temperature at which the cooling capacity should be increased and a set value lower than the reference value for the oil temperature are determined in advance for the oil temperature, and in step S1, the tank oil detected by the oil temperature sensor 13 is detected. The temperature and the reference value are compared.
[0044]
If YES here, that is, if the tank oil temperature is higher than the reference value, a large tilt command is issued to the work pump regulator 5 through the electromagnetic proportional valve 11 in step S2.
[0045]
As a result, the discharge amount of the work pump 3 increases, and the large flow rate is cooled by the oil cooler 8, so that the oil temperature rapidly decreases and the cooling capacity of the traveling circuit is increased.
[0046]
On the other hand, if NO (less than the reference value) in step S1, it is further determined in step S3 whether or not the tank oil temperature is equal to or higher than the set value. If NO (less than the set value), there is no need to increase the cooling capacity. In step S4, the work pump 3 is controlled to the small tilt side (for example, the minimum tilt).
[0047]
On the other hand, if it is determined in step S3 that the tank oil temperature is equal to or higher than the set value, it is determined in step S5 whether or not the pump was previously controlled to the large tilt side. The pump 3 is controlled to the small tilt side, and if YES, the work pump 3 is controlled to the large tilt side in step S2.
[0048]
By the control of step S3 → step S5 → step S2, when the work pump 3 is once controlled to the large tilt side, the large tilt is maintained until the tank oil temperature falls below the set value.
[0049]
In this way, by controlling the cooling capacity according to the tank oil temperature, it becomes possible to cool the traveling circuit more efficiently and maintain the traveling circuit at a more appropriate temperature.
[0050]
In the above example, the tilt of the work pump 3 is switched only to two types, large and small. However, the tilt of the pump is changed in three or more stages or continuously in a stepless manner in accordance with a change in the tank oil temperature. You may.
[0051]
Further, when the pump displacement is switched only between two sizes, an oil temperature switch that is turned on (or off) at a set temperature is used instead of the oil temperature sensor 13, and an electromagnetic switching valve is used instead of the electromagnetic proportional valve 11. May be used. In this case, the electromagnetic switching valve may be directly switched by turning on / off the oil temperature switch without using the controller 10.
[0052]
Second embodiment (see FIG. 3)
Only differences from the first embodiment will be described.
[0053]
In the second embodiment, assuming the configuration of the first embodiment,
(B) Drain oil returning from the traveling circuit to the oil tank T is cooled by a unique oil cooler,
(B) A configuration is provided in which the traveling speed reducer 31 is also cooled at the same time.
[0054]
That is, an auxiliary oil cooler 35 for drain is provided in the merged drain pipe 34, and a reduction gear cooling pipe 36 branched from the drain pipe 33 of the motor circuit B and passing through the traveling reduction gear 31 is provided.
[0055]
Reference numeral 37 denotes a check valve provided in parallel with the auxiliary oil cooler 35, and reference numeral 38 denotes a check valve for preventing reverse flow of oil from the reduction gear cooling pipe 36 to the traveling motor 22 side.
[0056]
According to this configuration, after the drain oil from the traveling circuit is cooled by the auxiliary oil cooler 35, it returns to the oil tank T, and receives the main cooling action of the work pump 3 and the oil cooler 8 thereon. This is particularly effective in vehicles in which the maximum discharge amount of the work pump 3 is small and the main cooling function may not be sufficient.
[0057]
In addition, since drain oil is supplied to the traveling speed reducer 31 by the speed reducer cooling pipe 36 and the traveling oil is cooled by the drain oil, overheating of the traveling speed reducer 31 can also be prevented.
[0058]
The auxiliary oil cooler 35 may be arranged in the engine room in front of the radiator together with the oil cooler 8 so as to be cooled by a common fan. In this case, the two oil coolers 8, 35 may be arranged side by side in front of the radiator, or may be arranged in front and back.
[0059]
【The invention's effect】
As described above, according to the present invention, the drain line of the traveling circuit is directly connected to the oil tank to shorten the entire length of the drain line, and while the components of the traveling circuit are prevented from being damaged by the back pressure during traveling, Since the working hydraulic pump is driven to circulate the oil in the working circuit through the oil cooler and the tank oil cooled by this is supplied to the running circuit by the replenishing pump, the running system equipment (hydraulic motor, Hydraulic pump) can be efficiently cooled.
[0060]
Further, since the replenishing oil is cooled using the working hydraulic pump, it is advantageous in terms of cost and energy efficiency as compared with the case where another pump is added.
[0061]
In this case, according to the invention of claims 3 and 4, in order to increase the discharge amount of the working hydraulic pump when the oil temperature rises, the cooling efficiency by the oil cooler is increased to keep the oil temperature at an appropriate temperature, and the cooling performance of the traveling circuit is improved. It can be kept constant.
[0062]
According to the invention of claim 5, since the oil cooler is also provided in the drain pipe line, the drain oil in the traveling circuit is cooled by the oil cooler for the drain, and the oil cooler in the working circuit is high. Cooling performance can be obtained.
[0063]
According to the sixth aspect of the present invention, a part of the drain oil is passed through the traveling speed reducer to cool the same speed reducer and prevent overheating thereof.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram showing a first embodiment of the present invention.
FIG. 2 is a flowchart for explaining a pump control operation in the embodiment.
FIG. 3 is a circuit diagram showing a second embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 motor 3 working hydraulic pump 4 traveling hydraulic pump 5 regulator of working hydraulic pump constituting pump control means 10 controller 11 electromagnetic proportional valve 13 oil temperature sensor 16 auxiliary pump (oil supply pump)
22 Hydraulic motor A for traveling A Pump circuit B constituting a traveling circuit B Motor circuit 6 Working circuit 8 Oil cooler 30 for working circuit Swivel joint 31 Travel reducers 32, 33, 34 Drain line 35 Auxiliary oil cooler 36 for drain Reduction gear cooling line

Claims (6)

An upper revolving structure is rotatably mounted on the lower traveling structure, and a prime mover is mounted on the upper revolving structure, and both working and traveling hydraulic pumps driven by the prime mover during traveling are provided. A working circuit for driving the working hydraulic actuator, an oil tank, and an oil cooler for cooling oil returning from the working circuit to the oil tank are provided, and a traveling hydraulic motor as a traveling drive source is provided on the lower traveling body. The traveling hydraulic motor and the traveling hydraulic pump are connected via a swivel joint to form a closed circuit traveling circuit. During traveling, the drain oil of the traveling circuit is directly supplied to the oil tank by a drain line. On the other hand, the work hydraulic pump is driven to circulate oil between the work circuit and the oil tank via the oil cooler, and the oil in the oil tank is discharged. Upper revolving type hydraulic driving method of the traveling system cooling a vehicle, characterized in that cooling the traveling system and supplied to the travel circuit by supply pump. An upper revolving structure is rotatably mounted on the lower traveling structure. A motor is mounted on the upper revolving structure, a traveling hydraulic pump driven by the prime mover during traveling, and a work driven by the prime mover during operation and traveling. A hydraulic circuit for driving, a working circuit for driving a working hydraulic actuator using the working hydraulic pump as a hydraulic source, an oil tank, and an oil cooler for cooling oil returning from the working circuit to the oil tank. A traveling hydraulic motor as a traveling drive source is provided on the lower traveling body, and the traveling hydraulic motor and the traveling hydraulic pump are connected via a swivel joint to constitute a closed circuit traveling circuit, and A drain pipe for directly returning the drain oil of the traveling circuit to the oil tank and an oil supply pump for supplying oil from the oil tank to the traveling circuit are provided. The oil is circulated between the work circuit and the oil tank via the oil cooler by the work hydraulic pump during traveling, and the oil in the oil tank is supplied to the travel circuit by the oil supply pump during traveling. An upper turning hydraulic traveling vehicle characterized by being configured as described above. 3. The hydraulic pump according to claim 2, wherein a variable displacement hydraulic pump is used as the working hydraulic pump, and pump control means for controlling a discharge amount of the hydraulic pump to increase when the oil temperature rises is provided. Top-turn hydraulic traveling vehicle. The pump control means includes a pump regulator for controlling the tilting of the working hydraulic pump, an electromagnetic proportional valve for sending an operating pressure to the pump regulator, an oil temperature detecting means for detecting the oil temperature, and detection by the oil temperature detecting means. 4. The upper turning hydraulic traveling vehicle according to claim 3, further comprising a controller that controls the operation of the electromagnetic proportional valve according to the oil temperature to be applied. The upper turning hydraulic traveling vehicle according to any one of claims 2 to 4, wherein a drain oil cooler is provided in the drain pipeline. 6. A reduction gear cooling pipe line for passing a part of the drain oil of the travel circuit through a travel reducer for reducing the rotational force of the travel hydraulic motor is provided. An upper turning hydraulic traveling vehicle as described in the above.

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