JP5072746B2 - Hydraulic circuit cooling system - Google Patents

Description

  The present invention relates to a cooling system for a hydraulic circuit in a construction machine and the like, and more particularly to a cooling system for a construction machine that efficiently cools a control valve.

  Conventionally, a cooling system for a hydraulic circuit as shown in FIG. 3 is known. That is, an oil cooler is provided in the return hydraulic fluid flow path from the hydraulic actuator and the control valve in order to cool the hydraulic fluid in the hydraulic circuit.

  In addition, there is known a hydraulic fluid cooling system for a construction machine in which an oil cooler is disposed between a hydraulic pump and a control valve in order to suppress deterioration of hydraulic equipment such as a hydraulic actuator and a valve (for example, Patent Document 1). ).

Furthermore, in order to suppress deterioration of the control valve, there is known a hydraulic oil cooling system provided with a water passage that allows the control valve to pass cooling water (for example, Patent Document 2).
JP 2007-51454 A JP 2007-85090 A

  In the case of Patent Document 1, the pressure loss in the oil cooler is large, and the efficiency of the hydraulic circuit is deteriorated. Moreover, even if pressure loss occurs in the oil cooler, in order to keep the pressure of the pressure oil supplied to the hydraulic actuator sufficiently, to secure the necessary flow rate, and to obtain a sufficient cooling effect with the oil cooler, Requires a very large oil cooler.

  In the case of Patent Document 2, power for circulating the cooling water to the cooling device for cooling the control valve is required, and the efficiency of the hydraulic system is deteriorated. Furthermore, in this case, both cooling water and pressure oil need to be cooled, and the capacity of the cooler needs to be increased.

  Accordingly, an object of the present invention is to improve the efficiency of a hydraulic circuit by efficiently cooling the hydraulic circuit.

  A hydraulic circuit cooling system according to an embodiment of the present invention includes a hydraulic actuator (10), a hydraulic pump (20) that supplies hydraulic oil to the hydraulic actuator (10), and the hydraulic pressure from the hydraulic pump (20). A control valve (30) provided in a supply flow path (P1, P2, P3) for supplying hydraulic oil to the actuator (10), and a return flow path through which the return hydraulic oil from the hydraulic actuator (10) passes. A cooling device (28) provided in P4) for cooling the hydraulic oil, and a control valve cooling provided in or around the control valve (30) through which the hydraulic oil cooled by the cooling device (28) flows. A flow path (36).

  In a preferred embodiment, the return hydraulic fluid from the hydraulic actuator (10) flows to the cooling device (28) or bypasses the cooling device (28) to the control valve cooling flow path (36). A switching valve (40) that switches between flowing and a temperature sensor (50) that is provided in the return flow path (P4) and measures the temperature of the return hydraulic oil from the hydraulic actuator (10), When the temperature of the return hydraulic oil from the hydraulic actuator (10) measured by the temperature sensor (50) is equal to or lower than a predetermined temperature, the return hydraulic oil from the hydraulic actuator (10) bypasses the cooling device (28). The switching valve (40) may perform channel switching so as to flow to the control valve cooling channel (36).

  In a preferred embodiment, the control valve (30) further includes a leakage oil passage (34) on the surface of the control valve (30) through which leakage hydraulic oil leaked from the passage in the control valve (30) flows. The flow path (36) may be disposed adjacent to the leaking oil flow path (34), and may cool the leaking hydraulic oil flowing through the leaking oil flow path (34).

  Hereinafter, a cooling system for a hydraulic circuit according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a hydraulic circuit cooling system 1 used in a construction machine or the like according to an embodiment of the present invention.

  The hydraulic circuit cooling system 1 includes a hydraulic actuator 10 that operates a working machine of a construction machine, a hydraulic pump 20 that is driven by an engine 24 and supplies hydraulic oil to the hydraulic actuator 10, a hydraulic actuator 10, and a hydraulic pump 20. And a control valve 30 that switches between supplying or stopping the hydraulic oil to the hydraulic actuator 10.

  The control valve 30 includes a control valve main body 32 and a control valve cooling flow path 36 for cooling the control valve main body 32.

  The control valve main body 32 is, for example, a solenoid valve, and in accordance with an instruction from a control device (not shown), the supply of hydraulic oil to the hydraulic actuator 10 is stopped, the hydraulic oil supply to the head side, and the hydraulic oil supply to the bottom side are switched. Do.

  The control valve cooling flow path 36 is a cooling flow path that is disposed inside a housing (not shown) of the control valve 30 and through which hydraulic oil cooled by the cooling device 28 flows. As will be described later, the control valve cooling flow path 36 is disposed near the flow path through which the hydraulic oil leaking from the control valve main body 32 flows, in particular, in order to cool the hydraulic oil leaking from the control valve main body 32. The control valve cooling flow path 36 may be arranged outside the housing (not shown) of the control valve 30 and may cool the control valve main body 32 from the outside of the housing.

  The hydraulic pump 20 supplies hydraulic oil to the control valve body 32 via the flow path P1. The return hydraulic oil from the control valve main body 32 flows through the flow path P4. The control valve main body 32 has a flow path P2 connected to the cylinder bottom side of the hydraulic actuator 10 and a flow path P3 connected to the cylinder head side.

  In the flow path P4, a temperature sensor 50 and a cooling device 28 for cooling the hydraulic oil by the cooling fan 26 are provided.

  In the hydraulic circuit having the above-described configuration, the hydraulic oil circulates as follows. That is, when the hydraulic pump 20 sucks up the hydraulic oil from the oil tank 22 and supplies the hydraulic oil to the control valve main body 32 via the flow path P1, the hydraulic pump 20 via the flow path P2 or P3 according to the state of the control valve main body 32, Hydraulic oil is supplied to the hydraulic actuator 10. Then, the hydraulic oil returning from the hydraulic actuator 10 via the flow path P2 or P3 and the hydraulic oil leaking from the control valve main body 32 flows into the flow path P4. Here, the hydraulic oil is cooled by the cooling device 28 provided in the flow path P4. The hydraulic oil cooled by the cooling device 28 is supplied to the control valve cooling flow path 36 via the flow path P5. The hydraulic oil that has cooled the control valve main body 32 in the control valve cooling flow path 36 returns to the oil tank 22.

  The flow path P4 is further provided with a switching valve 40 for bypassing the cooling device 28. In other words, if the hydraulic oil flows through the switching valve 40, the hydraulic oil can be supplied to the control valve cooling flow path 36 without passing through the cooling device 28. The switching valve 40 may be switched according to the temperature measured by the temperature sensor 50. That is, when the hydraulic oil is lower than a predetermined temperature, the control device (not shown) may open the switching valve 40 and supply the hydraulic oil to the control valve cooling flow path 36 without passing through the cooling device 28.

  FIG. 2 is a view schematically showing a cross section of the control valve main body 32.

  The control valve main body 32 includes a spool 33 that switches the flow path, and a leak oil pipe 34 that flows the leaked hydraulic oil leaking from the periphery of the spool 33 to the flow path P4. The control valve cooling flow path 36 is disposed at a position adjacent to the leakage oil pipe 34.

  As a result, the hydraulic oil leaking from the control valve body 32 can be intensively cooled. This is because the flow rate of the leaked oil is very small compared to the flow path P1 and the like, and can be cooled efficiently.

  The hydraulic oil cooled in the leakage oil pipe 34 flows from here to the cooling device 28 via the flow path P4 and is cooled by the cooling device 28. Therefore, the cooling by the cooling device 28 can also be performed efficiently.

  According to the present embodiment, since the control valve is cooled using the cooled return hydraulic oil, the cooling can be efficiently performed only by adding a simple configuration to the conventional hydraulic circuit. In particular, in this embodiment, a pipe through which the cooled return hydraulic oil flows is arranged next to the pipe through which the hydraulic oil leaked from the control valve flows, and the hydraulic oil leaked from the control valve is cooled by the cooling device. The oil can be efficiently cooled by intensive cooling immediately before.

  The above-described embodiments of the present invention are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

It is a lineblock diagram of cooling system 1 of a hydraulic circuit concerning one embodiment of the present invention. It is the figure which showed the cross section of the control valve main body typically. It is the cooling system of the conventional hydraulic circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic circuit cooling system 10 Hydraulic actuator 20 Hydraulic pump 22 Oil tank 24 Engine 26 Cooling fan 28 Cooling device 30 Control valve 32 Control valve main body 33 Spool 34 Oil piping 36 Control valve cooling flow path 40 Switching valve 50 Temperature sensor

Claims (3)

A hydraulic actuator (10);
A hydraulic pump (20) for supplying hydraulic oil to the hydraulic actuator (10);
A control valve (30) provided in a supply flow path (P1, P2, P3) for supplying hydraulic oil from the hydraulic pump (20) to the hydraulic actuator (10);
A cooling device (28) provided in a return flow path (P4) through which the return hydraulic oil from the hydraulic actuator (10) passes, and for cooling the hydraulic oil;
A hydraulic circuit cooling system comprising: a control valve cooling flow path (36) provided inside or around the control valve (30) and through which hydraulic oil cooled by the cooling device (28) flows. A switching valve that switches between returning hydraulic oil from the hydraulic actuator (10) to the cooling device (28) or bypassing the cooling device (28) and flowing to the control valve cooling flow path (36). (40)
A temperature sensor (50) provided in the return flow path (P4) for measuring the temperature of the return hydraulic oil from the hydraulic actuator (10),
When the temperature of the return hydraulic oil from the hydraulic actuator (10) measured by the temperature sensor (50) is equal to or lower than a predetermined temperature, the return hydraulic oil from the hydraulic actuator (10) bypasses the cooling device (28). The hydraulic circuit cooling system according to claim 1, wherein the switching valve (40) switches the flow path so as to flow to the control valve cooling flow path (36). Further provided on the surface of the control valve (30) is a leakage oil passage (34) through which leakage hydraulic oil leaked from the passage in the control valve (30) flows.
The said control valve cooling flow path (36) is arrange | positioned adjacent to the said leakage oil flow path (34), and cools the leakage hydraulic fluid which flows through the said leakage oil flow path (34), Item 3. The hydraulic circuit cooling system according to Item 1 or 2.

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