JP4069803B2 - Top-slewing hydraulic vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic traveling vehicle such as a wheel crane that has an upper turning type and has an HST (Hydrostatic Transmission), and a cooling method for the traveling system.
[0002]
[Prior art]
In an HST vehicle, a traveling hydraulic pump and a hydraulic motor are connected by a main line to form a closed circuit. Therefore, the replacement of oil in the traveling circuit is small enough to replenish the circuit with the shortage due to drainage. It becomes.
[0003]
Therefore, since the oil temperature in the traveling circuit becomes high and the equipment is likely to be overheated, it is necessary to cool the traveling circuit.
[0004]
Conventionally, as a technique for cooling equipment in an HST vehicle, a technique is known in which drain oil from a running circuit is temporarily accumulated in a motor case and a pump case, the hydraulic motor and the hydraulic pump are cooled, and the drain oil that has absorbed heat is returned to the tank. (For example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 5-27421 [0006]
[Problems to be solved by the invention]
However, when the known technique for cooling equipment using drain oil as a cooling medium is diverted to an upper-turning type HST vehicle, the following problems arise.
[0007]
For example, in a rough terrain crane that is a kind of wheel crane, when the lower traveling body is driven by a hydraulic motor with HST, the hydraulic motor is provided in the lower traveling body, whereas the prime mover, hydraulic pump, and tank are Since it is provided in the upper swing body, the main pipeline and drain pipeline on the hydraulic pump side and the main pipeline and drain pipeline on the hydraulic motor side are each connected by a long pipeline via a swivel joint.
[0008]
Therefore, if the above-described known technique is used as it is, the total length of the drain line of the traveling system becomes long and the back pressure increases, so that the back pressure load on each part 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 running circuit is the shortest, connecting the pipe line directly to the oil tank instead of relaying it with a motor case or pump case as in the known art, the drain circuit of the liver kidney drain oil The cooling action of the equipment (motor and pump) is lost.
[0010]
Accordingly, the present invention provides an upper-slewing hydraulic traveling vehicle capable of efficiently cooling the equipment of the traveling circuit, and a method for cooling the traveling system, with the configuration in which the drain line of the traveling system is directly connected to the oil tank. It is to provide.
[0011]
[Means for Solving the Problems]
The inventions of claim 1, the upper swing structure is mounted pivotably on the lower traveling body, and the prime mover to the upper rotating body, a traveling oil pressure pump driven by the prime mover during traveling, the working time and travel A variable displacement working hydraulic pump driven by the prime mover over time, a working circuit that drives the working hydraulic actuator using the working hydraulic pump as a hydraulic source, an oil tank, and an oil tank from the working circuit to the oil tank. Back while the oil cooler for cooling the oil is kicked set, the traveling hydraulic motor serving as the lower traveling body drive source is provided, and the travel hydraulic motor and the travel hydraulic pump via a swivel joint travel circuit of connected closed circuit is formed, and a drain line for returning drain oil of the travel circuit directly the oil tank, to the travel circuit from the oil tank An oil supply pump for replenishing, the discharge amount of the hydraulic pump for the working respectively provided and a pump control means for controlling the direction of increasing the time of rising oil temperature, oil the oil by the upper Symbol working hydraulic pump during traveling via cooler is circulated between the working circuit and the oil tank, in which the oil in the oil tank is configured so that teapot complement to the travel circuit by the oil supply pump.
[0012]
Of inventions the claims 2, in the configuration of claim 1, pump control means includes a pump regulator for controlling a tilting of the working hydraulic pump, an electromagnetic proportional valve sending the operating pressure to the pump regulator, an oil temperature The oil temperature detecting means for detecting and a controller for controlling the operation of the electromagnetic proportional valve in accordance with the oil temperature detected by the oil temperature detecting means .
[0013]
According to a third aspect of the present invention, in the configuration of the first or second aspect, a drain oil cooler is provided in the drain line .
[0014]
A fourth aspect of the present invention, in the construction of claims 1 to 3, a portion of the drain oil of the travel circuit, reduction gear cooling pipe through the traveling speed reducer for reducing the rotating force of the travel hydraulic motor is it is those provided we were.
[0015]
According to the above configuration , since the drain oil of the running circuit is directly returned to the oil tank, the total length of the drain pipe can be shortened to a minimum as compared with a known technique that temporarily accumulates in the motor case or the pump case. For this reason, the back pressure of the drain pipe line can be suppressed and damage to each part of the device can be prevented.
[0016]
In addition, during driving, the working hydraulic pump is driven to circulate the oil in the working circuit via the oil cooler, and the oil cooled thereby is replenished to the traveling circuit by the replenishing pump, so the oil temperature in the traveling circuit is lowered. The traveling circuit can be efficiently cooled.
[0017]
Further, since the replenishment 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.
[0018]
In this case , since the discharge amount of the working hydraulic pump is increased when the oil temperature rises, the cooling efficiency by the oil cooler can be increased, the oil temperature can be kept at an appropriate temperature, and the cooling performance of the traveling circuit can be kept constant.
[0019]
Further, according to the configuration of the third aspect, since the oil cooler is also provided in the drain pipe line, the drain oil of the traveling circuit is cooled by the drain oil cooler, which is high in combination with the cooling action by the oil cooler of the work circuit. Cooling performance can be obtained.
[0020]
According to the configuration of the fourth aspect , since part of the drain oil is passed through the travel speed reducer, the travel speed reducer can be cooled together with the travel circuit, and overheating can be prevented.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0022]
First embodiment (see FIGS. 1 and 2)
In FIG. 1, reference numeral 1 denotes a prime mover. The prime mover 1 drives both working and traveling hydraulic pumps (hereinafter referred to as working pump and traveling pump) 3 and 4 via a power distributor 2.
[0023]
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 unillustrated work hydraulic actuators (not shown) provided in the work circuit 6 by pressure oil from the pump 3. In the case of a rough terrain crane, a boom hoisting cylinder, a winch motor, a turning motor, etc.) are driven.
[0024]
An oil cooler 8 is provided in the tank line 7 of the work circuit 6, and the return oil that has come out of the actuator of the work circuit 6 is cooled by the oil cooler 8 and returns to the oil tank T. A check valve 9 is provided in parallel with the oil cooler 8.
[0025]
The work pump regulator 5 is connected to a pilot pressure source 12 via an electromagnetic proportional valve 11 controlled by a controller 10, and is based on a signal from the controller 10 in accordance with 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 working pump regulator 5 changes and the pump tilt is controlled in magnitude (this will be described in detail later).
[0026]
On the other hand, the traveling pump 4 is configured as a variable displacement pump that is bidirectional and whose tilt is controlled by the traveling pump regulator 14.
[0027]
The travel circuit using the travel pump 4 as a hydraulic source is composed of a pump circuit A and a motor circuit B. The pump circuit A is connected to the upper swing body together with the work pump 3 and the work circuit 6 and related devices, and the motor circuit B is connected to the upper circuit. It is installed in each lower traveling body.
[0028]
The pump circuit A includes a traveling pump 4, an electromagnetic switching valve 15 that controls the operation of the traveling pump regulator 14 based on a signal from the controller 10, and a fixed displacement auxiliary pump (oil replenishment) that sucks oil from the oil tank T. A pump 16, a throttle 17 that generates a pressure corresponding to the discharge amount of the auxiliary pump 16, and a pressure reducing valve 18 that reduces the pressure generated by the throttle 17 and sends it to the traveling pump regulator 14 via the electromagnetic switching valve 15. A low pressure relief valve 19, overload relief valves 20 and 20 for regulating the maximum circuit pressure, and check valves 21 and 21 for replenishing the circuit with a part of the oil from the auxiliary pump 16. ing.
[0029]
The motor circuit B includes a traveling hydraulic motor (hereinafter referred to as a traveling motor) 22, a flushing valve 23 that discharges excess oil to the outside of the circuit, a throttle 24 and a flow control valve 25 provided on the downstream side of the flushing valve 23. The both-side motor lines 26 and 27 of the motor circuit B and the both-side main lines 28 and 29 of the pump circuit A are connected via a swivel joint 30 to form a closed circuit.
[0030]
A traveling speed reducer 31 decelerates the rotational force of the traveling motor 22 and transmits it to traveling driving wheels (not shown).
[0031]
Also, the pump side drain pipe 32 into which the leakage oil from the traveling pump 4 and the relief oil from the low pressure relief valve 19 flow into the pump circuit A, and the leakage oil and flushing valve from the traveling motor 22 into the motor circuit B. Motor side drain pipes 33 into which oil discharged from the engine 23 flows are provided, and both the drain pipe lines 32 and 33 are connected to the tank T via the swivel joint 30 and the merging drain pipe line 34.
[0032]
As described above, since the drain pipes 32, 33, and 34 are connected to the tank T through the shortest path, the pipe length can be minimized. Accordingly, even in an upper turning type vehicle in which the drain line length becomes long, the back pressure generated in the travel circuit by the drain lines 32, 33, and 34 can be kept low. ) Back pressure load is reduced and these damages are prevented.
[0033]
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 the oil from the auxiliary pump 16 travels via the electromagnetic switching valve 15. The inclination of the traveling pump 4 is increased by being sent to the pump regulator 14.
[0034]
Thereby, the oil discharged from the pump 4 is sent to the motor circuit B, the travel motor 22 rotates, and the vehicle travels.
[0035]
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 oiled via the drain conduits 32 and 33 and the merged drain conduit 34. Returned to tank T.
[0036]
On the other hand, although the work circuit 6 is stopped at this time, the work pump 3 is driven, and the oil discharged from the pump 3 passes through the work circuit 6 and is cooled by the oil cooler 8 to be cooled in the oil tank T, and further to the pump 3. Circulate to
[0037]
Due to the circulation of the working system oil, the drain oil from the travel circuit is cooled and then replenished to the travel circuit by the auxiliary pump 16, so that the travel is a closed circuit including the travel pump 4 and the travel motor 2. The circuits (pump circuit A and motor circuit B) are cooled.
[0038]
That is, the drain circuit 32, 33, 34 is connected directly to the oil tank T without passing through the pump case or the motor case as in a known technique, and the running circuit is connected to the low temperature through the oil cooler 8. It can be cooled with oil and kept at an appropriate temperature.
[0039]
In this case, since a large flow rate of oil discharged from the work pump 3 is cooled by the oil cooler 8, the temperature of the tank oil can be efficiently cooled, and thereby the cooling action of the traveling circuit can be efficiently performed.
[0040]
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.
[0041]
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 are determined in advance, and the tank oil detected by the oil temperature sensor 13 in step S1. The temperature and the reference value are compared.
[0042]
If YES, that is, if the tank oil temperature is higher than the reference value, a large tilt is commanded to the work pump regulator 5 through the electromagnetic proportional valve 11 in step S2.
[0043]
Thereby, since the discharge amount of the work pump 3 is increased and the large flow rate is cooled by the oil cooler 8, the oil temperature is quickly lowered, and the cooling capacity of the traveling circuit is increased.
[0044]
On the other hand, if NO in step S1 (below the reference value), it is further determined in step S3 whether the tank oil temperature is equal to or higher than the set value. If NO (below the set value), it is not necessary to increase the cooling capacity. In step S4, the work pump 3 is controlled to the small tilt side (for example, the minimum tilt).
[0045]
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 previous pump was controlled to the large tilt side. If NO, the operation is performed in step S4. 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.
[0046]
By the control of step S3 → step S5 → step S2, once the working pump 3 is controlled to the large tilt side, the large tilt is maintained until the tank oil temperature falls below the set value.
[0047]
Thus, by controlling the cooling capacity according to the tank oil temperature, it is possible to cool the traveling circuit more efficiently and keep it at a more appropriate temperature.
[0048]
In the above example, the tilt of the work pump 3 is switched to only two types of large and small. However, the pump tilt is changed in three or more steps or continuously in accordance with the change in the tank oil temperature. May be.
[0049]
Also, when the pump tilt is switched only in two ways, the oil temperature sensor 13 is replaced with an oil temperature switch that is turned on (or off) at the set temperature, and the electromagnetic switching valve 11 is replaced with an electromagnetic switching valve. May be used. In this case, a configuration in which the electromagnetic switching valve is directly switched by turning on / off the oil temperature switch without using the controller 10 may be employed.
[0050]
Second embodiment (see FIG. 3)
Only differences from the first embodiment will be described.
[0051]
In the second embodiment, assuming the configuration of the first embodiment,
(B) Cool the drain oil returning from the running circuit to the oil tank T with its own oil cooler,
(B) A configuration for cooling the traveling speed reducer 31 at the same time is added.
[0052]
That is, a drain auxiliary oil cooler 35 is provided in the merging drain pipe 34, and a speed reducer cooling pipe 36 that branches from the drain pipe 33 of the motor circuit B and passes through the traveling speed reducer 31 is provided.
[0053]
37 is a check valve provided in parallel with the auxiliary oil cooler 35, and 38 is a check valve for preventing the backflow of oil from the speed reducer cooling pipeline 36 to the traveling motor 22 side.
[0054]
According to this configuration, the drain oil from the running circuit is cooled by the auxiliary oil cooler 35 and then returned to the oil tank T, and further receives the main cooling action by the work pump 3 and the oil cooler 8, so that the cooling effect is enhanced. In particular, the effect is exhibited in a vehicle in which the maximum discharge amount of the work pump 3 is small and the main cooling action may not be sufficient.
[0055]
Further, since the drain oil is supplied to the traveling speed reducer 31 by the speed reducer cooling pipe 36 and the traveling speed reducer 31 is cooled by the drain oil, overheating of the traveling speed reducer 31 can also be prevented.
[0056]
The auxiliary oil cooler 35 may be arranged together with the oil cooler 8 in front of the radiator in the engine room and air-cooled by a common fan. In this case, both the oil coolers 8 and 35 may be arranged side by side in front of the radiator, or may be arranged in the front and rear.
[0057]
【The invention's effect】
As described above, according to the present invention, the drain pipeline of the running circuit is directly connected to the oil tank to shorten the total length of the drain pipeline, while preventing damage to each part of the running circuit due to the back pressure. Since the working hydraulic pump is driven to circulate the oil in the working circuit via the oil cooler and the tank oil cooled thereby is replenished to the traveling circuit by the replenishing pump, the traveling system equipment (hydraulic motor, The hydraulic pump can be efficiently cooled.
[0058]
Further, since the replenishment 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.
[0059]
In this case , since the discharge amount of the working hydraulic pump is increased when the oil temperature rises, the cooling efficiency by the oil cooler can be increased, the oil temperature can be kept at an appropriate temperature, and the cooling performance of the traveling circuit can be kept constant.
[0060]
According to the invention of claim 3 , since the drain cooler is also provided with the oil cooler, the drain oil of the traveling circuit is cooled by the oil cooler for the drain and is high in combination with the cooling action by the oil cooler of the work circuit. Cooling performance can be obtained.
[0061]
According to the invention of claim 4 , a part of the drain oil can be passed through the travel speed reducer to cool the speed reducer and to prevent overheating.
[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 action in the embodiment.
FIG. 3 is a circuit configuration diagram showing a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Prime mover 3 Working hydraulic pump 4 Traveling hydraulic pump 5 Regulator of working hydraulic pump constituting pump control means 10 Same controller 11 Same electromagnetic proportional valve 13 Same oil temperature sensor 16 Auxiliary pump (oil supply pump)
DESCRIPTION OF SYMBOLS 22 Hydraulic motor for driving A Pump circuit which comprises driving circuit B Same motor circuit 6 Working circuit 8 Oil cooler for working circuit 30 Swivel joint 31 Traveling reducer 32, 33, 34 Drain line 35 Auxiliary oil cooler 36 for drain Reducer cooling line

Claims (4)

Upper rotating body is mounted pivotably on the lower traveling body, and the prime mover to the upper rotating body, a traveling oil pressure pump driven by the prime mover during travel, it is driven by the prime mover through during work and during travel A variable displacement working hydraulic pump, a working circuit that drives the working hydraulic actuator using the working hydraulic pump as a hydraulic source, an oil tank, and an oil cooler that cools oil returning from the working circuit to the oil tank; There while eclipsed set, the traveling hydraulic motor serving as the lower traveling body drive source is provided, and the travel hydraulic motor and the travel hydraulic pump is connected via a swivel joint with the travel circuit closed circuit There is constructed, and the oil supply for replenishing the drain line for returning drain oil of the travel circuit directly the oil tank, the oil to the travel circuit from the oil tank Pump and the discharge amount of the hydraulic pump for the working respectively provided and a pump control means for controlling the direction of increasing the time of rising oil temperature, the working oil by the upper Symbol working hydraulic pump via the oil cooler during running is circulated between the circuit and the oil tank, the upper revolving hydraulic vehicle the oil in the oil tank, characterized in that configured so that teapot complement to the travel circuit by the oil supply pump both. The pump control means is detected by a pump regulator that controls the tilting of the working hydraulic pump, an electromagnetic proportional valve that sends operating pressure to the pump regulator, an oil temperature detection means that detects the oil temperature, and the oil temperature detection means. 2. The upper-turning hydraulic traveling vehicle according to claim 1 , further comprising a controller that controls the operation of the electromagnetic proportional valve in accordance with the oil temperature . The upper turning hydraulic traveling vehicle according to claim 1 or 2 , wherein a drain oil cooler is provided in the drain line . A part of drain oil of the travel circuit, any one of claims 1 to 3, wherein the reduction gear cooling pipe is provided et the passage through the traveling speed reducer for reducing the rotating force of the travel hydraulic motor upper revolving type hydraulic traveling vehicle according to.

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