JP2001132710A - Self-propelled working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-propelled working machine with no damage of the cooling function of a radiator caused by heat from an oil cooler facing the radiator especially in running. SOLUTION: This self-propelled working machine is equipped with a running car body having an engine 6 and the radiator 8, a hydraulic circuit 50 having a working machine mounted on the running car body, an actuator for driving the working machine, pipelines 21-24 for supplying hydraulic oil to the actuator, a returning pipeline 32 through which returning oil from the actuator flows, and an oil cooler 15 arranged in the return passage, so as to face the radiator and for cooling the hydraulic oil; a blower means 9 for cooling the hydraulic oil being introduced into the oil cooler and a cooling fluid which is introduced into the radiator by forming the air flow going from the oil cooler side to the radiator side, a detecting means 18 for detecting a working state and a running state; and control means 35, 36, 40 for controlling the flow of the hydraulic oil to the oil cooler based on the detected information from the detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-propelled work machine, and more particularly to a self-propelled work machine in which an oil cooler and a radiator are air-cooled by a fan rotated by the power of an engine.

[0002]

2. Description of the Related Art Generally, a self-propelled working machine such as a crane truck or a power shovel has a working machine mounted on a traveling vehicle body. The working machine includes an operating device such as a boom, an arm, and a bucket. These actuators are driven by hydraulically operated actuators such as hydraulic cylinders and hydraulic motors.

An example of a hydraulic circuit for driving the actuator is schematically shown in FIG. As shown, the oil in the oil tank T is supplied to the engine 1 of the traveling vehicle body.
The inside of the pressure oil supply line 102 is pressure-fed by a hydraulic pump P driven by the power of 14, and is supplied to an actuator while its flow is controlled by a direction control valve or the like.

[0004] Return oil from the actuator is collected in an oil tank T via a return pipe 104.

Generally, an oil cooler 110 is interposed in the return line 104 in order to cool oil (hereinafter, referred to as hydraulic oil) which is pumped in the lines 102 and 104. In the air cooling system, the hydraulic oil guided to the oil cooler 110 is:
Normally, the engine 114 is cooled together with cooling water (coolant) guided to the radiator 112 by cooling the engine 114.
Is cooled by a common fan 116 rotated by the power of In this case, the oil cooler 110 is usually arranged to face the front of the radiator 112, and the oil cooler 110
The fan 116 is rotated so that an air flow from the side to the radiator 112 side is formed. That is, the airflow formed by the rotation of the fan 116 passes through the oil cooler 110 to cool the working oil guided thereto, and then cools through the radiator 112 to cool the cooling water guided thereto.

[0006]

As shown in FIG. 7, an oil cooler 110 and a radiator 112 are arranged to face each other. A front surface of the radiator 112 is covered by the oil cooler 110, and the oil cooler 110 Is formed toward the radiator 112 from the oil cooler 110 when the high-temperature hydraulic oil is guided to the oil cooler 110, unlike the case where the front of the radiator 112 is opened. The temperature of the passing air rises due to the heat from the hydraulic oil, and the heated air flows into the radiator 112 (the cooling water flowing through the radiator 112 is cooled by the high-temperature air).
The cooling capacity of the radiator 112 will deteriorate.

[0007] However, in general, during work in which only the actuator is driven without the traveling vehicle body traveling,
The rotation speed of the engine 114 is low (the pump P
Since the cooling water does not rise to a very high temperature, a serious trouble such as overheating of the engine 114 is rarely caused by a decrease in the cooling capacity on the radiator 112 side. That is,
Even if the air flowing to the radiator 112 is restricted by the oil cooler 110,
Even if the engine 1 is warmed by the hydraulic oil flowing through the
If the rotation speed of the engine 14 is low, the heat of the cooling water flowing through the radiator 112 can be radiated to a temperature at which the engine 114 can be cooled.

On the other hand, when the engine 114 runs at a high rotational speed, the temperature of the cooling water guided to the radiator 112 becomes high, so that a decrease in the cooling capacity on the radiator 112 side becomes a serious problem. In particular, when high-temperature hydraulic oil flows into the oil cooler 110 during traveling, the air heated by the hydraulic oil flows into the radiator 112 to which the high-temperature cooling water is guided. May not be able to sufficiently dissipate heat.

A crane truck can be cited as an example in which high-temperature operating oil flows through the oil cooler 110 during traveling. The crane vehicle includes a revolving body having a working machine mounted on a traveling vehicle body so as to be pivotable, and includes a plurality of hydraulic pumps P for controlling a plurality of actuator groups by different systems. These hydraulic pumps P are usually driven by the power of the engine 114 during the operation of operating the actuator. However, some hydraulic pumps P involved in the operation of the power steering and the swing body (slewing motor)
Is constantly driven even during traveling. Therefore, hydraulic oil flows into the oil cooler 110 not only at the time of work but also at the time of traveling.

As described above, when high-temperature operating oil is fed into the oil cooler 110 even during traveling, as described above, air warmed by the operating oil flows into the radiator 112 through which high-temperature cooling water is guided. Therefore, the heat of the cooling water cannot be sufficiently radiated by the radiator 112, and the engine 114 may be overheated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent the cooling function of the radiator from being impaired by the heat from the oil cooler facing the radiator, especially during running. An object of the present invention is to provide a self-propelled working machine.

[0012]

In order to solve the above-mentioned problems, a self-propelled working machine according to the present invention comprises a traveling vehicle having an engine and a radiator, a traveling machine mounted on the traveling vehicle, and a traveling machine. A hydraulically actuated actuator for driving the
A pressure oil supply line that supplies hydraulic oil from the oil tank to the actuator via a hydraulic pump, a return line that returns oil from the actuator to the oil tank, and a return line that faces the radiator And a hydraulic circuit equipped with an oil cooler for cooling the hydraulic oil flowing through the return line, and by rotating the engine with the power of the engine to form an air flow from the oil cooler side to the radiator side, Blower means for cooling the working oil guided to the oil cooler and the coolant guided to the radiator; detecting means for detecting a working state in which the working machine is driven and a traveling state in which the traveling vehicle body is traveling; and the detecting means And control means for controlling the flow of hydraulic oil to the oil cooler based on the detection information from the control unit.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment of the present invention. As shown in FIG. 4, a wheel crane (rough terrain crane) 1 as a self-propelled work machine according to the present embodiment includes a carrier 2 as a traveling vehicle body. A revolving body (both not shown) as a working machine having a telescopic boom (actuator) is rotatably mounted on a revolving bearing 4 on the carrier 2 via a revolving table (not shown). The telescopic boom is composed of a plurality of stages of booms that are telescopically connected, is extendable by a telescopic cylinder (actuator) (not shown), and extends between the revolving structure and the lower surface of the base end boom. The undulating operation is performed by an undulating cylinder (actuator) (not shown).

The wheel crane 1 is provided with a dual-purpose operation cab (not shown) on the revolving structure that can perform both the crane operation and the traveling operation.

An engine 6 is mounted on a rear portion of the carrier 2. A fan 9 as a blower is disposed behind the engine 6. The fan 9 is attached to a rotating shaft extending from the engine 6 and is rotated by the power of the engine 6. A radiator 8 is disposed on the rear side of the fan 9 so as to face the fan 9. In addition, as clearly shown in FIG. 3, an oil cooler 15 described below is arranged on the rear side of the radiator 8 so as to face the front surface of the radiator 8. That is, cooling water (coolant) guided to the radiator 8 by cooling the engine 6 and hydraulic oil described later guided to the oil cooler 15 are cooled by the common fan 9 rotated by the power of the engine 6. It has become.

In this embodiment, the oil cooler 15
The fan 9 is rotated such that an air flow from the side toward the radiator 8 is formed. That is, the airflow formed by the rotation of the fan 9 passes through the oil cooler 15 to cool the hydraulic oil guided thereto, and then cools through the radiator 8 to cool the cooling water guided thereto.

As shown in FIG. 2, a torque converter 25 is connected to the engine 6. The torque converter 25 includes a pump impeller 26 directly connected to a crankshaft of the engine 6, a turbine liner 27, and a lock-up clutch 28. Turbine 27
Is connected to a first output shaft 29, and the first output shaft 2
9 is connected to the transmission 30.
Further, the impeller 27 is connected to the second output shaft 29b, the drive shaft 3 of the turning pumps P ₃ and steering pump P ₄ will be described later, via the second output shaft 29b
8 (see FIG. 1). In addition, impeller 27
Is also connected to the third output shaft 29c. The third output shaft 29c is connected to a well-known PTO (power take-off) 1
8, it is connected to a drive shaft 37 (see FIG. 1) of crane pumps P ₁ , P ₂ described below. PTO18
Is turned on / off in response to an operation signal from a traveling / work changeover switch provided in the cab, and
The connection state between c and the drive shafts 37 of the crane pumps P ₁ and P ₂ is controlled. Specifically, when PTO18 is turned ON, the pump _P 1 for the third output shaft 29c cranes, _{P 2}
Of the engine 6 is transmitted to the crane pumps P ₁ and P ₂ (the pumps P ₁ and P ₂ are driven). Further, when PTO18 is turned OFF, the third output shaft 29c and the drive shaft 37 crane pump _P 1, _{P 2} is disconnected (connected state is canceled), the pump _{P 1} for the power of the engine 6 crane , not transmitted to _{P 2} (the driving of the pump _P 1, _{P 2} is stopped).

[0019] That is, in this embodiment, the a transmission 30 and a turning pump P ₃ and the steering pump P _4, whether during traveling and the working time, the power is constantly transmitted to the engine 6 via the torque converter 25 And
The power of the engine 6 is transmitted to the crane pumps P ₁ and P ₂ only when the PTO 18 is turned on.

The PTO 18 is connected to a third output shaft 29c.
And a detecting means for detecting a connection state between the driving shafts 37 of the crane pumps P ₁ and P ₂ . This detection means,
When PTO18 there is a third output shaft 29c and the drive shaft 37 of the crane pump _P 1, _{P 2} is OFF is disconnected, the control unit will be described below this forms the detection signal S 40
(See FIG. 1).

As described above, the actuator such as the boom is driven by actuators such as the up-and-down cylinder and the telescopic cylinder. A hydraulic circuit 50 for driving these actuators is shown in FIG.

As shown, the hydraulic circuit 50 includes a tank T
Pumps P for pumping oil inside₁, P₂,
P₃, P₄have. First pump P for crane
₁The first hydraulic supply line 21 extending from the discharge side of the
Rear 2 side piping (hydraulic piping, air piping, electrical wiring, etc.)
Rotary seal connecting the rotating body and the piping on the revolving structure side
(Rotary joint) 20 and directional control not shown
Connects to the telescopic cylinder and the up-and-down cylinder via a valve, etc.
Has been continued. Also, a second pump P for the crane ₂of
The second hydraulic supply line 22 extending from the discharge side is provided with a rotary
Actuator for driving winch through seal 20
Connected to a hydraulic motor (not shown)
You. Also, the turning pump P₃The third extending from the discharge side of
The hydraulic supply line 23 is provided via the rotary seal 20
A swing module as an actuator that drives the swing body to swing
Data (not shown). Also stearin
Hydraulic supply line 2 extending from the discharge side of the pump P4
Reference numeral 4 denotes a steering wheel through a rotary seal 20.
Orbit drop as actuator linked to eel
(Not shown).

As described above, the turning pump P ₃
A steering pump P _4, whether during traveling and the working time, the power from the engine 6 is driven is always transmitted to the drive shaft 38. On the other hand, the crane pumps P ₁ and P ₂
The power is transmitted from the engine 6 to the drive shaft 37 only when the PTO 18 is turned on.

The hydraulic circuit 50 has a return line 32 for returning the return oil from each actuator to the tank T. An oil cooler 1 for cooling the oil flowing therethrough (hereinafter referred to as hydraulic oil) is provided in the return line 32.
5 are interposed. The return pipe 32 is provided with an on-off valve 35 at a position upstream of the oil cooler 15. The on-off valve 35 is normally set to an open position, and is switched to a closed position when receiving pilot pressure from an electromagnetic valve 36. The solenoid valve 36 is electrically connected to the control unit 40, and is switched to an ON state in which a pilot pressure is applied to the on-off valve 35 when a control signal C is received from the control unit 40. The control unit 40 is electrically connected to the detection means of the PTO 18, and receives a detection signal S from the detection means, and controls a control signal C for switching the solenoid valve 36 to the ON state.
And outputs this to the solenoid valve 36.

The hydraulic circuit 50 is connected to a portion of the return line 32 located upstream of the on-off valve 35 and the oil cooler 1.
5 is provided with a bypass line 34 for connecting to a portion of the return line 32 located downstream of the line 5. Bypass line 34
Is provided with a check valve 42 that opens toward the tank T.

Next, the operation of the wheel crane 1 having the above configuration will be described.

First, a description will be given of a working state in which the PTO 18 is turned on by the running / work changeover switch in the cab and the power of the engine 6 is not transmitted to the axle. In this working state, the power of the engine 6 is
Are transmitted to the four pumps P ₁ , P ₂ , P ₃ and P ₄ via the second and third output shafts 29b and 29c. Therefore, each actuator can be driven, and work can be performed according to various operations.

In this working state, the third output shaft 2
9c and the drive shafts 37 of the crane pumps P ₁ and P ₂ are connected to each other.
The detection signal S is not sent to 0, and the solenoid valve 36 is maintained in the OFF state. That is, the on-off valve 35 is maintained at the open position. Therefore, the high-temperature hydraulic oil returned from the actuator can flow through the return line 32 to the oil cooler 15 (of course, if it exceeds the cracking pressure of the check valve 42, it can flow through the bypass line 34). .

The hydraulic oil guided to the oil cooler 15 is cooled by the fan 9 rotated by the power of the engine 6.
Returned to tank T. At this time, the temperature of the air passing through the oil cooler 15 rises due to the heat from the hydraulic oil,
The air whose temperature has risen flows into the radiator 8,
The rotation speed of the engine 6 in the working state is low (the pumps P ₁ , P ₂ , P ₃ , and P ₄ are driven at a low rotation speed), and the cooling water flowing through the radiator 8 has not risen to a high temperature. The cooling water is sufficiently cooled by the warmed air from the oil cooler 15 side.

Next, a description will be given of a traveling state in which the PTO 18 is turned off by the traveling / work changeover switch in the cab and the power of the engine 6 is transmitted to the axle.

In this running state, not only the axle but also the second
P ₃ and turning the pump via the output shaft 29b of the power of the engine 6 to the steering pump P ₄ is transmitted.
Further, in this running state, since the third output shaft 29c and the drive shaft 37 of the crane pump _P 1, _{P 2} are disconnected, the detection signal to the control unit 40 from the sensing means PTO18 S
Is sent. Therefore, the control unit 40 sends the electromagnetic valve 36
Is output, and the solenoid valve 36 is switched to the ON state. That is, the pilot pressure acts on the on-off valve 35 from the solenoid valve 36, and the on-off valve 35 is switched to the closed position. Therefore, the hydraulic fluid being pumped through the conduit 23,24,32 by turning pumps _{P 3} and steering pump _{P 4} is not flow through the oil cooler 15, through the bypass conduit 34, is returned to the tank T. as a result,
The air passing through the oil cooler 15 due to the rotation of the fan 9 can flow into the radiator 8 without increasing the temperature, and can sufficiently radiate the heat of the cooling water that has reached a high temperature by the high-speed engine 6.

As described above, the wheel crane 1 of the present embodiment is provided with the detecting means for detecting the working state and the traveling state, and the flow of the hydraulic oil to the oil cooler 15 is controlled by the detecting information from the detecting means. It is supposed to be. Specifically, the crane pumps P ₁ and P ₁ are provided by the PTO 18 provided in the torque converter 25.
Transmission of the engine power is controlled for _2, PTO18
The opening / closing valve 35 interposed in the return pipe line 32 is opened and closed by the detection information from the detecting means provided in the control unit. In particular, in the present embodiment, the crane pump P
At the time of traveling in which the transmission of the engine power to P1 and P2 is interrupted, a detection signal S is output from the detection means of the PTO 18 to the control unit 40, and the on-off valve 35 is closed. That is, the operating oil does not flow into the oil cooler 15 during traveling. Therefore, the air passing through the oil cooler 15 due to the rotation of the fan 9 can flow into the radiator 8 without increasing the temperature, and the heat of the cooling water that has reached a high temperature by the high-speed engine 6 can be sufficiently radiated. it can. That is, the cooling function of the radiator 8 is not impaired by the heat from the oil cooler 15, and the overheating of the engine 6 is prevented. Needless to say, the hydraulic oil remaining in the oil cooler 15 approaches the atmospheric temperature in the oil cooler 15, so that the engine 6
It does not hinder the cooling of the car.

In this embodiment, the running state and the working state are detected by the signal from the PTO 18,
Pump signal or crane from the shift range _P 1, _{P 2}
The traveling state and the work state may be detected based on the discharge pressure signal of the second embodiment.

FIG. 5 shows a second embodiment of the present invention. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, a temperature sensor 54 for detecting the temperature of the hydraulic oil flowing through the return line 32 is provided in the middle of the return line 32. This temperature sensor 54
Is electrically connected to the control unit 40, and the return line 3
When the temperature of the hydraulic oil flowing through the second unit 2 is lower than the set temperature, a detection signal is sent to the control unit 40. Further, when receiving the detection signal from the temperature sensor 54, the control unit 40 outputs the control signal C to the electromagnetic valve 36 and closes the on-off valve 35 regardless of the presence or absence of the detection signal S from the PTO 18. Other configurations and control modes are the same as those of the first embodiment.

According to such a configuration, the same operation and effect as those of the first embodiment can be obtained, and the hydraulic oil is prevented from being excessively cooled by the oil cooler 15.

It should be noted that a detection signal may be sent from the temperature sensor 54 to the control unit 40 when the temperature of the hydraulic oil flowing through the return line 32 is higher than the set temperature. In this case, when receiving the detection signal from the temperature sensor 54, the control unit 40 stops the output of the control signal C and opens the on-off valve 35 even when the detection signal S is received from the PTO 18. . However, during traveling, the on-off valve 35 is closed again when the temperature of the hydraulic oil drops to a predetermined temperature so that the engine 6 does not overheat. By adopting such a control form, it is possible to prevent the hot hydraulic oil that has not been sufficiently cooled from being forcibly returned to the tank T during traveling.

In the running state, the on-off valve 35 may be opened only at the initial stage when the engine 6 is started. This is advantageous in that the warm-up operation can be shortened particularly when the engine 6 is cold in winter or the like.

FIG. 6 shows a third embodiment of the present invention. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown, in this embodiment, the on-off valve 3
5 is interposed in the bypass line 34 instead of the return line 32. In this case, the on-off valve 35 is normally set to the closed position, and is switched to the open position when receiving pilot pressure from the solenoid valve 36. On the other hand, the check valve 42 is interposed in a pipe 59 connecting the upstream side and the downstream side of the oil cooler 15, and releases the pressure on the upstream side of the oil cooler 15 to the downstream side, and The 15 side is prevented from being in an overpressure state. Other configurations and control modes are the same as those of the first embodiment.

In such a configuration, during traveling, the on-off valve 35
Is opened, hydraulic oil flows through the bypass line 34, and the return line 32 is not closed.
The hydraulic oil also flows through the oil cooler 15. However, when the on-off valve 32 is opened, the flow toward the oil cooler 15 having a large pipeline resistance is largely regulated (most of the hydraulic oil flows through the bypass pipeline 34 having a small pipeline resistance,
Only a small amount of hydraulic oil flows to the oil cooler 15)
Therefore, the same operation and effect as in the first embodiment can be obtained.

The present invention is not limited to the above embodiment, but can be variously modified without departing from the scope of the invention. For example, in the above embodiment, a crane truck is illustrated as a self-propelled work machine, but the present invention can be applied to a construction work machine such as a power shovel and other workable work mechanisms.

[0043]

As described above, according to the self-propelled working machine of the present invention, the cooling function of the radiator is not impaired by the heat from the oil cooler facing the radiator, especially during traveling.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hydraulic circuit of a self-propelled work machine according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a power transmission mechanism from an engine to an axle of the self-propelled work machine according to the first embodiment.

3A is a side view showing an arrangement state of an engine, a radiator, and an oil cooler, and FIG. 3B is a view in the direction of arrow A in FIG.

FIG. 4 is a perspective view of a traveling vehicle body of the self-propelled work machine according to the first embodiment.

FIG. 5 is a configuration diagram of a hydraulic circuit of a self-propelled work machine according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a hydraulic circuit of a self-propelled working machine according to a third embodiment of the present invention.

FIG. 7 is a conventional hydraulic circuit diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wheel crane (self-propelled working machine) 2 ... Carrier (traveling vehicle body) 6 ... Engine 8 ... Radiator 9 ... Fan (blowing means) 15 ... Oil tank 18 ... PTO (Detecting means) 21, 22, 23, 24 ... Pressure oil supply line 32 Return line 35 Open / close valve (control means) 36 Solenoid valve (control means) 40 Control unit (control means) 54 Temperature sensors (temperature detection means) P ₁ , P ₂ , P _3, P 4 _... hydraulic pump T ... oil tank

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01P 11/10 F01P 11/10 K

Claims (3)

[Claims] 1. A traveling vehicle having an engine and a radiator, a working machine mounted on the traveling vehicle, a hydraulically operated actuator for driving the working machine, and hydraulic oil from an oil tank to the actuator via a hydraulic pump. A pressure oil supply line to be supplied, a return line for returning the return oil from the actuator to the oil tank, and a cooling oil that is interposed in the return line so as to face the radiator and cools the hydraulic oil flowing through the return line. A hydraulic circuit having an oil cooler and an engine cooler that is rotated by the power of the engine and forms an air flow from the oil cooler side to the radiator side, and the hydraulic oil guided to the oil cooler and the cooling oil guided to the radiator Blowing means for cooling the liquid, detecting means for detecting a working state in which the working machine is driven and a running state in which the running vehicle body is running, Control means for controlling a flow of hydraulic oil to an oil cooler based on detection information from the detection means. 2. The self-propelled work machine according to claim 1, wherein the control means does not supply hydraulic oil to an oil cooler when the control means detects that the vehicle is running. 3. The hydraulic pump is connected to an output side of an engine to be driven with the power of the engine, and the detecting means detects a connection state between the output side of the engine and the hydraulic pump. The self-propelled work machine according to claim 1, wherein the work state and the running state are distinguished by: