Work machinery and hydraulic control devices

Abstract

This invention provides a work machine that addresses the problem of hydraulic fluid temperature rise when hydraulic fluid is supplied to a breaker from multiple hydraulic pumps. [Solution] The work machine 1 of the present invention is a work machine 1 that can use a breaker (hydraulic breaker 431) on a tip attachment 43, and the work machine 1 is equipped with a hydraulic control device CTU that switches between a single-flow supply control, which supplies hydraulic fluid from a first hydraulic pump P1 to a first hydraulic circuit HC1 that returns hydraulic fluid to a tank TK for storing hydraulic fluid via an oil cooler OC without going through a breaker, and a combined-flow supply control, which supplies hydraulic fluid from a first hydraulic pump P1 and a second hydraulic pump P2 to a second hydraulic circuit HC2 that returns hydraulic fluid to a tank TK via a breaker without going through an oil cooler OC, according to a first setting condition.

Description

Technical Field

[0001] The present invention relates to a working machine and a hydraulic control device.

Background Art

[0002] In Patent Document 1, there are provided a first hydraulic pump that discharges hydraulic fluid, an actuator drive circuit that drives an actuator by flowing the hydraulic fluid of the first hydraulic pump to the actuator, a hydraulic motor that rotates a cooling fan at a rotational speed corresponding to the flow rate of the supplied hydraulic fluid, a second hydraulic pump that discharges hydraulic fluid in conjunction with the first hydraulic pump, a fan drive circuit that drives the hydraulic motor by flowing the hydraulic fluid of the second hydraulic pump to the hydraulic motor, a connection and disconnection switching between the actuator drive circuit and the fan drive circuit, a merging circuit that merges the hydraulic fluid of the actuator drive circuit into the fan drive circuit when the actuator drive circuit and the fan drive circuit are connected, and a control device that controls the merging circuit so as to connect between the actuator drive circuit and the fan drive circuit when a predetermined merging condition is satisfied. A hydraulic drive system is disclosed.

[0003] And in Patent Document 1, it is described that with the above configuration, when a predetermined condition is satisfied, the cooling capacity of the cooling fan by the cooling fan drive device can be further increased by one step.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a working machine such as an excavator, there may be a case where the tip attachment is replaced with a breaker to crush rocks or the like, and when using the breaker, there is a demand to use a breaker with a large output (tonnage).

[0006] In this case, if the work machine has two hydraulic pumps, it is possible to address the issue by combining the hydraulic fluid from the two hydraulic pumps and supplying it to the breaker.

[0007] However, the hydraulic circuit used to drive the breaker is designed to return the hydraulic fluid to the storage tank without passing through the oil cooler, bypassing the breaker and the oil cooler, in order to avoid damage to the oil cooler caused by pulsations of the hydraulic fluid that occur when the breaker is driven.

[0008] Therefore, even if the cooling fan capacity of the oil cooler is improved, it does not contribute to cooling the hydraulic fluid, resulting in a problem of the hydraulic fluid temperature rising.

[0009] This invention has been made in view of these circumstances, and aims to provide a work machine that addresses the problem of temperature rise of hydraulic fluid when hydraulic fluid is supplied to a breaker from multiple hydraulic pumps. [Means for solving the problem]

[0010] To achieve the above objective, the present invention is understood by the following configuration. The work machine of the present invention is Lower running body and An upper slewing body is provided so as to be rotatable relative to the lower traveling body, A work mechanism is provided on the upper rotating body, and a breaker can be used as the tip attachment, A tank for storing hydraulic fluid is provided in the upper rotating body, A first hydraulic circuit returns the hydraulic fluid from the tank to the tank via an oil cooler without passing through the breaker, A first hydraulic pump capable of supplying hydraulic fluid from the tank to the first hydraulic circuit, A second hydraulic circuit is used when the aforementioned breaker is used, and returns the hydraulic fluid from the tank to the tank via the breaker without passing through the oil cooler. A second hydraulic pump capable of supplying the hydraulic fluid from the tank to the second hydraulic circuit, A switching valve that switches the supply destination of the hydraulic fluid from the first hydraulic pump to the first hydraulic circuit or the second hydraulic circuit, The system includes a hydraulic control device that controls the supply of the hydraulic fluid, When the breaker is used, the hydraulic control device switches the switching valve according to the first setting conditions for switching the switching valve, and switches from combined supply control, which supplies hydraulic fluid from the first hydraulic pump and the second hydraulic pump to the second hydraulic circuit, to single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump to the first hydraulic circuit and the hydraulic fluid from the second hydraulic pump to the second hydraulic circuit.

[0011] The hydraulic control device for a work machine that can use a breaker as an end attachment of the present invention is When using the breaker, the hydraulic control device switches from a single-flow supply control, which supplies the hydraulic fluid from the first hydraulic pump to a second hydraulic circuit that returns the hydraulic fluid from the first and second hydraulic pumps to the tank via the breaker without passing through the oil cooler, to a single-flow supply control, which supplies the hydraulic fluid from the first and second hydraulic pumps to the tank via the breaker without passing through the oil cooler, according to a first setting condition. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a work machine that addresses the problem of temperature rise of hydraulic fluid when hydraulic fluid is supplied to a breaker from multiple hydraulic pumps. [Brief explanation of the drawing]

[0013] [Figure 1] This is a side view of a work machine according to the first embodiment of the present invention. [Figure 2] This is a circuit diagram illustrating the first hydraulic circuit and the like of the first embodiment according to the present invention. [Figure 3]This is a circuit diagram for explaining a second hydraulic circuit and the like according to the first embodiment of the present invention. [Figure 4] This is a circuit diagram for explaining a third hydraulic circuit and the like according to the first embodiment of the present invention. [Figure 5] This is a flowchart showing the control when using a hydraulic breaker performed by the hydraulic control device according to the first embodiment of the present invention. [Figure 6] This is a diagram showing the flow of hydraulic oil in the normal standby state immediately before operating the hydraulic breaker according to the first embodiment of the present invention. [Figure 7] This is a diagram showing the flow of hydraulic oil when driving the hydraulic breaker according to the first embodiment of the present invention with hydraulic oil from a first hydraulic pump and a second hydraulic pump. [Figure 8] This is a diagram showing the flow of hydraulic oil when driving the hydraulic breaker according to the first embodiment of the present invention only with hydraulic oil from a second hydraulic pump. [Figure 9] This is a flowchart showing the control when using a hydraulic breaker performed by the hydraulic control device according to the second embodiment of the present invention. [Figure 10] This is a flowchart showing the control when using a hydraulic breaker performed by the hydraulic control device according to the third embodiment of the present invention. [Figure 11] This is a flowchart showing the control when using a hydraulic breaker performed by the hydraulic control device according to the fourth embodiment of the present invention. [Figure 12] This is a flowchart showing the control when using a hydraulic breaker performed by the hydraulic control device according to the fifth embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "embodiments") will be described in detail with reference to the accompanying drawings. Throughout the description of the embodiments, the same elements are denoted by the same numbers or symbols.

[0015] However, please note that, for the sake of readability in the drawings, not all identical elements are assigned numbers or symbols, and some elements do not have numbers or symbols assigned.

[0016] <<First Embodiment>> A work machine 1 that can use a breaker (hydraulic breaker 431) on the tip attachment 43 of the first embodiment of the present invention, and a hydraulic control unit CTU of the work machine 1 will be described with reference to Figures 1 to 8.

[0017] Figure 1 is a side view of a work machine 1 according to the first embodiment of the present invention. Figure 1 is a left side view of the work machine 1, taken from the rear when the upper rotating body 30 is viewed from the rear, with the side containing the operator's cab 31 of the upper rotating body 30 being the front and the opposite side being the rear.

[0018] Furthermore, in the following explanation, the side of the upper rotating body 30 where the driver's cab 31 is located will be referred to as the front, the opposite side as the rear, and the left side when viewing the upper rotating body 30 from the rear will be referred to as the left, and the right side as the right.

[0019] As shown in Figure 1, the work machine 1 comprises a crawler-type lower traveling body 10, an upper rotating body 30 provided via a rotating section 20 so as to be rotatable relative to the lower traveling body 10, and a work mechanism 40 provided on the upper rotating body 30 so as to be able to raise and lower, and a hydraulic breaker 431 that can be used on the tip attachment 43. In the following text, the hydraulic breaker 431 may be simply referred to as "breaker."

[0020] In the first embodiment, the tip attachment 43 is shown to be a hydraulic breaker 431, but the work machine 1 may also use, if necessary, a bucket or the like for the tip attachment 43.

[0021] The upper rotating body 30 includes a driver's cab 31 at the front, which has an operating section (not shown) for an operator to board and perform various operations, and a machine room 32 located behind the driver's cab 31.

[0022] The working mechanism 40 includes a boom 41 whose base end is provided so as to be able to raise and lower relative to the upper slewing body 30, an arm 42 whose base end is provided so as to be able to rotate relative to the tip of the boom 41, and a tip attachment 43 (in this example, a hydraulic breaker 431) whose base end is provided so as to be able to rotate at the tip of the arm 42.

[0023] Furthermore, the working mechanism 40 includes a boom cylinder 41A for luffing the boom 41 relative to the upper slewing body 30, an arm cylinder 42A for rotating the arm 42 relative to the boom 41, and a tip attachment cylinder 43A for rotating the tip attachment 43 relative to the arm 42. The boom cylinder 41A, arm cylinder 42A, and tip attachment cylinder 43A are all hydraulic cylinders.

[0024] Figure 2 is a circuit diagram illustrating the first hydraulic circuit HC1, etc., of the first embodiment according to the present invention. Figure 3 is a circuit diagram illustrating the second hydraulic circuit HC2, etc., of the first embodiment according to the present invention. Figure 4 is a circuit diagram illustrating the third hydraulic circuit HC3, etc., of the first embodiment according to the present invention.

[0025] Although the first hydraulic pump P1 and the second hydraulic pump P2 are connected to the tank TK to draw hydraulic fluid, in Figures 2 to 4, for the sake of clarity, the diagrams omit showing the connections between the first hydraulic pump P1 and the second hydraulic pump P2 to the tank TK. Instead, to make the flow of hydraulic fluid easier to understand, the oil passages (hydraulic circuits) through which the hydraulic fluid flows from the tank TK to the tank TK are highlighted.

[0026] In other words, even when hydraulic fluid is being supplied, we avoid highlighting oil passages that are dead ends and where there is no flow of hydraulic fluid.

[0027] Furthermore, in Figures 2 to 4, the flow of control signals between the hydraulic control unit (CTU) and each component is shown by dotted arrows.

[0028] Furthermore, although the diagram omits the illustration of the hydraulically driven drive units other than the breaker, which are driven by hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2, and the oil passages from these drive units other than the breaker back to the tank TK, the hydraulic fluid returning to the tank TK from these drive units other than the breaker all passes through the oil cooler OC.

[0029] The hydraulically driven drive units other than the breaker specifically include a pair of hydraulic motors (not shown) provided on the lower traveling body 10, a slewing motor (not shown) for slewing the upper slewing body 30, a boom cylinder 41A, an arm cylinder 42A, and a tip attachment cylinder 43A, etc.

[0030] As shown in Figures 2 to 4, the work machine 1 includes a tank TK for storing hydraulic fluid provided on the upper slewing body 30, a temperature measuring unit TM for measuring the temperature of the hydraulic fluid in the tank TK provided on the upper slewing body 30, a first hydraulic pump P1 provided on the upper slewing body 30, a second hydraulic pump P2 provided on the upper slewing body 30, and a power source EG provided on the upper slewing body 30 for driving the first hydraulic pump P1 and the second hydraulic pump P2.

[0031] For example, the power source EG can be an internal combustion engine or a motor, and it is sufficient if it can provide the rotational force necessary to drive the first hydraulic pump P1 and the second hydraulic pump P2 to the first hydraulic pump P1 and the second hydraulic pump P2.

[0032] Furthermore, the tank TK, temperature measurement unit TM, first hydraulic pump P1, second hydraulic pump P2, and power source EG are located in the machine room 32, in more detail.

[0033] Furthermore, the work machine 1 includes a first unload valve V1 provided on the upper slewing body 30, a second unload valve V2 provided on the upper slewing body 30, a confluence switching valve VC1 provided on the upper slewing body 30, a breaker switching valve VC2 provided on the upper slewing body 30, a hydraulic control device CTU provided on the upper slewing body 30 for controlling the supply of hydraulic fluid, a breaker operating unit OPS provided on the upper slewing body 30 for the operator to operate to drive the hydraulic breaker 431, a display unit (not shown) provided on the upper slewing body 30, and a storage unit (not shown) for storing various setting conditions. For example, the memory unit (not shown) may be provided integrally with the hydraulic control unit (CTU).

[0034] More specifically, the first unload valve V1, the second unload valve V2, the merging valve VC1, the breaker switching valve VC2, the hydraulic control unit CTU, and the memory unit (not shown) are located in the machine room 32, while the display unit (not shown) and the breaker operating unit OPS are located in the operator's cab 31. However, the hydraulic control unit (CTU) and the memory unit (not shown) may be located within the driver's cab 31, and the layout may be changed as necessary.

[0035] Furthermore, the work machine 1 is equipped with a first hydraulic sensor PS1 and a second hydraulic sensor PS2, both located on the upper rotating body 30.

[0036] For example, the first hydraulic sensor PS1 detects the hydraulic pressure of the hydraulic fluid in the first hydraulic circuit HC1 (described later), which is used by the hydraulic control unit CTU to control the drive state of the first hydraulic pump P1, and the second hydraulic sensor PS2 detects the hydraulic pressure of the hydraulic fluid in the second hydraulic circuit HC2 (described later) and the third hydraulic circuit HC3 (described later), which are used by the hydraulic control unit CTU to control the drive state of the second hydraulic pump P2.

[0037] More specifically, the first hydraulic sensor PS1 and the second hydraulic sensor PS2 are located within the machine room 32.

[0038] Next, the first hydraulic circuit HC1 will be explained with reference to Figure 2. As shown in Figure 2, the first hydraulic circuit HC1 is a hydraulic circuit that returns the hydraulic fluid from tank TK, supplied by the first hydraulic pump P1 which is capable of supplying hydraulic fluid from tank TK to the first hydraulic circuit HC1, to tank TK via the oil cooler OC without passing through the breaker 431.

[0039] Specifically, the first hydraulic circuit HC1 is a hydraulic circuit formed when the confluence switching valve VC1, which is a switching valve that switches the destination of the hydraulic fluid supply from the first hydraulic pump P1 to the first hydraulic circuit HC1 or the second hydraulic circuit HC2 described later, is switched so that hydraulic fluid is supplied to the first hydraulic circuit HC1 side, that is, so that hydraulic fluid is not supplied to the second hydraulic circuit HC2 described later, and the first unload valve V1 opens to allow the passage of hydraulic fluid.

[0040] Next, the second hydraulic circuit HC2 will be explained with reference to Figure 3. As shown in Figure 3, the second hydraulic circuit HC2 is a hydraulic circuit that returns the hydraulic fluid from tank TK, supplied by the second hydraulic pump P2 which is capable of supplying hydraulic fluid from tank TK to the second hydraulic circuit HC2, to tank TK via the hydraulic breaker 431 without passing through the oil cooler OC.

[0041] Specifically, the second hydraulic circuit HC2 is a hydraulic circuit formed when the breaker switching valve VC2 is switched so that hydraulic fluid from the second hydraulic pump P2 can be supplied to the hydraulic breaker 431, and the second unload valve V2 is closed so as not to allow the passage of hydraulic fluid, and is used when the hydraulic breaker 431 is in use.

[0042] Next, the third hydraulic circuit HC3 will be explained with reference to Figure 4. As shown in Figure 4, the third hydraulic circuit HC3 is a hydraulic circuit that returns the hydraulic fluid supplied from the second hydraulic pump P2 to the tank TK via the oil cooler OC, without passing through the breaker 431.

[0043] Specifically, the third hydraulic circuit HC3 is a hydraulic circuit formed when the breaker switching valve VC2 is switched so that hydraulic fluid from the second hydraulic pump P2 is not supplied to the hydraulic breaker 431, and the second unload valve V2 is opened to allow the passage of hydraulic fluid.

[0044] Next, with reference to Figures 5 to 8, the control performed by the hydraulic control unit CTU when using the hydraulic breaker 431 in the work machine 1 of the first embodiment will be described.

[0045] Figure 5 is a flowchart showing the control performed by the hydraulic control device CTU of the first embodiment of the present invention when using the hydraulic breaker 431. Note that the flowchart in Figure 5 starts during the normal standby state immediately before the hydraulic breaker 431 is activated.

[0046] This normal standby state is a condition in which the first hydraulic pump P1 and the second hydraulic pump P2 are started (e.g., by turning the key ON), and the first hydraulic pump P1 and the second hydraulic pump P2 are running, but all hydraulically driven drive units, including the hydraulic breaker 431, are not running, resulting in the first hydraulic pump P1 and the second hydraulic pump P2 being driven at a low speed.

[0047] Furthermore, when the hydraulic breaker 431 is operating, it is generally assumed that other hydraulically driven drive units are not in operation. Therefore, immediately before activating the hydraulic breaker 431, all hydraulically driven drive units, including the hydraulic breaker 431, are not operating. The flowchart in Figure 5 starts at the normal standby flow rate, where the flow rate of hydraulic fluid discharged from the first hydraulic pump P1 and the second hydraulic pump P2 is low.

[0048] Figure 6 shows the flow of hydraulic fluid in the normal standby state immediately before activating the hydraulic breaker 431 of the first embodiment according to the present invention, and corresponds to Figures 2 to 4.

[0049] As shown in Figure 6, immediately after the start of the flowchart in Figure 5, the confluence switching valve VC1, which is a switching valve that switches the destination of the hydraulic fluid supplied from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2 (see Figure 3), is switched by the hydraulic control unit CTU to supply the hydraulic fluid from the first hydraulic pump P1 to the first hydraulic circuit HC1.

[0050] Furthermore, the hydraulic control unit CTU opens the first unload valve V1 to allow the hydraulic fluid to pass through.

[0051] Therefore, the hydraulic fluid supplied from the first hydraulic pump P1 to tank TK is supplied to the first hydraulic circuit HC1 and returns to tank TK.

[0052] In other words, the low flow rate of hydraulic fluid supplied from the first hydraulic pump P1 during normal standby mode returns to the tank TK via the first unload valve V1 and the oil cooler OC, without passing through the hydraulic breaker 431.

[0053] Furthermore, as shown in Figure 6, immediately after the start of the flowchart in Figure 5, the hydraulic control device CTU switches the breaker switching valve VC2 so that hydraulic fluid from the second hydraulic pump P2 is not supplied to the hydraulic breaker 431, and the second unload valve V2 is opened to allow the passage of hydraulic fluid.

[0054] Therefore, the hydraulic fluid supplied from the second hydraulic pump P2 to tank TK is supplied to the third hydraulic circuit HC3 and returns to tank TK.

[0055] In other words, the low flow rate of hydraulic fluid supplied from the second hydraulic pump P2 during normal standby mode returns to the tank TK via the second unload valve V2 and the oil cooler OC, without passing through the hydraulic breaker 431.

[0056] (S10) In the above state, in S10 shown in Figure 5, the hydraulic control unit CTU operates the breaker operating unit OPS, which is operated by the operator to drive the hydraulic breaker 431, and monitors whether the breaker operation has been performed.

[0057] If the breaker operation is not performed (S10 is NO), the process returns to S10, and the hydraulic control unit (CTU) continues to monitor whether the breaker operation has been performed. If the breaker operation is performed (S10 is YES), the process proceeds to S11.

[0058] (S11) In S11, the hydraulic control unit CTU controls the supply of hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 to the second hydraulic circuit HC2, and then proceeds to S12.

[0059] Specifically, the hydraulic control unit CTU increases the output (rotational speed) of the first hydraulic pump P1 and the second hydraulic pump P2 to ensure the required hydraulic pressure at the hydraulic breaker 431, and switches the valves so that hydraulic fluid is supplied to the second hydraulic circuit HC2.

[0060] In other words, the hydraulic control unit CTU switches the confluence switching valve VC1, which is a switching valve that switches the destination of the hydraulic fluid supplied from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2 (see Figure 3), to supply the hydraulic fluid to the second hydraulic circuit HC2, and also closes the first unload valve V1 so that the hydraulic fluid does not pass through it.

[0061] Furthermore, the hydraulic control unit CTU switches the breaker switching valve VC2 so that the hydraulic fluid supplied from the second hydraulic pump P2 is supplied to the hydraulic breaker 431, and closes the second unload valve V2 so that the hydraulic fluid does not pass through the second unload valve V2.

[0062] Figure 7 shows the flow of hydraulic fluid when the hydraulic breaker 431 of the first embodiment according to the present invention is driven by hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2, and corresponds to Figures 2 to 4.

[0063] As shown in Figure 7, in this case, the hydraulic control unit CTU controls the hydraulic fluid from the first hydraulic pump P1 to the second hydraulic circuit HC2 by switching a confluence switching valve VC1, which is a switching valve that switches the destination of the hydraulic fluid from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2 (see Figure 3), thereby converging the hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 into the second hydraulic circuit HC2.

[0064] However, as can be seen in Figure 7, when using combined supply control, the hydraulic fluid from tank TK flows only to the second hydraulic circuit HC2, and therefore returns to tank TK without passing through the oil cooler OC.

[0065] Therefore, in the first embodiment, a temperature measuring unit TM is provided to measure the temperature of the hydraulic fluid in the tank TK, and a first setting condition is provided that includes a temperature threshold for the hydraulic fluid temperature when using the breaker (hydraulic breaker 431), and the hydraulic fluid temperature is monitored (S12) as described later. This first setting condition is pre-registered in the memory unit (not shown) described earlier.

[0066] (S12) In S12 shown in Figure 5, the hydraulic control unit CTU makes a decision to switch the merging valve VC1, which is a switching valve that switches the destination of the hydraulic fluid supply from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2, based on first setting conditions including a temperature threshold for the hydraulic fluid temperature when the breaker is used. Specifically, the hydraulic control unit CTU determines whether the temperature of the hydraulic fluid measured by the temperature measurement unit TM is within a temperature threshold.

[0067] Then, if the hydraulic fluid temperature is within the threshold (S12 is YES), proceed to S13; if the hydraulic fluid temperature exceeds the temperature threshold, proceed to S14.

[0068] (S13) In S13, the hydraulic control unit CTU determines whether hydraulic fluid from the first hydraulic pump P1 is being supplied to the first hydraulic circuit HC1.

[0069] Specifically, in S13, it is determined whether, in the past, the temperature of the hydraulic fluid exceeded the temperature threshold, and after going through the step of S14 described later, the hydraulic fluid from the first hydraulic pump P1 was supplied to the first hydraulic circuit HC1, and then the temperature of the hydraulic fluid returned to within the temperature threshold (S12 is YES), and the process proceeded to step S13.

[0070] Then, if S13 is YES, proceed to S15; if S13 is NO, proceed to S16.

[0071] (S14) In S14, according to a first setting condition (i.e., the temperature threshold has been exceeded) which includes a temperature threshold for the hydraulic fluid temperature when using the breaker, the hydraulic control unit CTU switches the confluence switching valve VC1, which is a switching valve that switches the destination of the hydraulic fluid supply from the first hydraulic pump P1 to the first hydraulic circuit HC1 (see Figure 2) or the second hydraulic circuit HC2 (see Figure 3). This switches the control from confluence supply control (see Figure 7), which supplies hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 to the second hydraulic circuit HC2, to single-flow supply control (see Figure 8), which supplies hydraulic fluid from the first hydraulic pump P1 to the first hydraulic circuit HC1 and hydraulic fluid from the second hydraulic pump P2 to the second hydraulic circuit HC2.

[0072] Thus, in the first embodiment, the hydraulic control device CTU performs control to switch from combined flow supply control to single flow supply control when the temperature of the hydraulic fluid measured by the temperature measurement unit TM exceeds a temperature threshold.

[0073] Specifically, the confluence switching valve VC1, which switches the destination of the hydraulic fluid supply from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2 (see Figure 3), is switched by the hydraulic control device CTU. As a result, the hydraulic fluid from the first hydraulic pump P1 is supplied to the first hydraulic circuit HC1, and the first unload valve V1 is opened so that the hydraulic fluid passes through the first unload valve V1.

[0074] Figure 8 shows the flow of hydraulic fluid when the hydraulic breaker 431 of the first embodiment according to the present invention is driven solely by the hydraulic fluid from the second hydraulic pump P2, and corresponds to Figures 2 to 4. In other words, Figure 8 shows the flow of hydraulic fluid after the processing in S14.

[0075] As shown in Figure 8, the hydraulic control unit CTU switches the merging valve VC1, which is a switching valve that switches the destination of the hydraulic fluid from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2 (see Figure 3), to supply the hydraulic fluid from the first hydraulic pump P1 to the first hydraulic circuit HC1. In S14, it performs control to switch to a single-flow supply control in which the hydraulic fluid from the first hydraulic pump P1 is supplied to the first hydraulic circuit HC1, and only the hydraulic fluid from the second hydraulic pump P2 is supplied to the second hydraulic circuit HC2.

[0076] When the temperature threshold is exceeded, the system switches to a single-flow supply control that supplies hydraulic fluid from the first hydraulic pump P1 to the first hydraulic circuit HC1. This causes the hydraulic fluid from the first hydraulic pump P1 to return to the tank TK via the oil cooler OC, thereby cooling the hydraulic fluid.

[0077] In this case, although the output of the hydraulic breaker 431 is lower than when the hydraulic breaker 431 was driven by the hydraulic pressure from the first hydraulic pump P1 and the second hydraulic pump P2, as in the combined supply control described earlier, it is possible to continue operations without stopping the hydraulic breaker 431.

[0078] Furthermore, when switching from combined flow control to single flow control, the output of the hydraulic breaker 431 decreases. Therefore, to inform the operator of the work machine 1 of this change, the display unit (not shown) described earlier may be configured to display that the system has switched to single flow control.

[0079] Thus, it is preferable that the work machine 1 is equipped with a display unit that can indicate that it has switched from combined flow supply control to single flow supply control.

[0080] Furthermore, as mentioned above, the purpose of switching to single-flow supply control in S14 is to cool the hydraulic fluid, so it is preferable that the flow rate of hydraulic fluid discharged from the first hydraulic pump P1 is high, and that a large amount of hydraulic fluid returns to the tank TK via the oil cooler OC.

[0081] Therefore, in this single-flow supply control, although the hydraulic fluid from the first hydraulic pump P1 flows along the same route as in the normal standby state, it is preferable not to use the low hydraulic fluid flow rate that occurs in the normal standby state.

[0082] Therefore, in the first embodiment, the hydraulic control device CTU performs a single-flow supply flow rate increase control, which increases the flow rate of the hydraulic fluid supplied from the first hydraulic pump P1 to the first hydraulic circuit HC1 when single-flow supply control is performed, to a higher amount than the flow rate in the normal standby state.

[0083] For example, one possible approach is to maintain the output (rotational speed) of the first hydraulic pump P1 even after the hydraulic control unit CTU switches from combined flow control to single flow control. In other words, it can maintain the output (rotational speed) of the first hydraulic pump P1 as it was when it was supplying hydraulic fluid to the second hydraulic circuit HC2 in order to supply the hydraulic breaker 431, thereby performing single-flow flow rate increase control to increase the flow rate above the normal standby flow rate.

[0084] In the above explanation, we described the case where switching to single-current supply control is performed based on a temperature threshold. However, for example, the first setting condition may also be a threshold for the elapsed time from the start of circuit breaker operation (also called the switching time threshold) for switching to single-current supply control.

[0085] (S15) S15 is a step that proceeds after S14 has enabled single-flow supply control (control that supplies hydraulic fluid from the first hydraulic pump P1 to the first hydraulic circuit HC1), and the hydraulic fluid has cooled down and the temperature of the hydraulic fluid has returned to within the temperature threshold (S12 is YES).

[0086] In this case, since the hydraulic fluid is within the temperature threshold, the hydraulic control device CTU switches from single-flow supply control to combined-flow supply control in order to increase the output of the hydraulic breaker 431. This control involves supplying hydraulic fluid from the first hydraulic pump P1 to the second hydraulic circuit HC2, and the process proceeds to S16.

[0087] Specifically, the hydraulic control unit CTU switches the confluence switching valve VC1, which is a switching valve that switches the destination of the hydraulic fluid supply from the first hydraulic pump P1 to either the first hydraulic circuit HC1 or the second hydraulic circuit HC2 (see Figure 3), so that the hydraulic fluid from the first hydraulic pump P1 is supplied to the second hydraulic circuit HC2, and the first unload valve V1 is closed so that the hydraulic fluid does not pass through it.

[0088] As mentioned earlier, if the display unit (not shown) is configured to indicate that the system has switched from combined supply control to single-current supply control, this display should be disabled so that it is clear that the system has returned to combined supply control.

[0089] However, the working machine 1 may be equipped with a display unit that can constantly show whether it is in combined supply control mode or single-flow supply control mode, so that the control status can be known at all times.

[0090] (S16) In S16, the hydraulic control unit CTU operates the breaker operating unit OPS, which is operated by the operator to drive the hydraulic breaker 431, to determine whether a breaker stop operation has been performed. If a breaker stop operation has been performed (S16 is YES), the series of processes ends. If a breaker stop operation has not been performed (S16 is NO), the process returns to S12 and performs the series of processes described above.

[0091] For example, if a circuit breaker stop operation is performed (S16 is YES), the hydraulic control unit CTU may monitor whether the next circuit breaker activation operation has been performed (see S10) while in the normal standby state described at the start of the flowchart in Figure 5.

[0092] According to the first embodiment of the work machine 1 described above, when hydraulic fluid is supplied from multiple hydraulic pumps (first hydraulic pump P1 and second hydraulic pump P2) to a breaker (hydraulic breaker 431), the hydraulic control unit CTU switches the supply of hydraulic fluid to single-flow supply control according to a first setting condition (for example, a hydraulic fluid temperature threshold), allowing the hydraulic fluid to be cooled while enabling the work at the breaker (hydraulic breaker 431) to continue, thereby ensuring work efficiency and addressing the problem of rising hydraulic fluid temperature.

[0093] Specifically, when using the breaker (hydraulic breaker 431), the hydraulic control unit CTU switches from a single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump P1 to the first hydraulic circuit HC1 that returns the hydraulic fluid to the tank TK where it is stored, via the oil cooler OC without passing through the breaker, to a combined supply control, which supplies hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 to the second hydraulic circuit HC2 that returns the hydraulic fluid to the tank TK via the breaker without passing through the oil cooler OC. This allows for cooling of the hydraulic fluid while enabling continued operation of the breaker (hydraulic breaker 431), thereby ensuring work efficiency and addressing the problem of rising hydraulic fluid temperature.

[0094] Moreover, with the configuration of the work machine 1 of the first embodiment, it is only necessary to switch from the first hydraulic circuit HC1, which supplies hydraulic fluid from the first hydraulic pump P1 during normal standby conditions, to the second hydraulic circuit HC2, thus suppressing the cost increase associated with significant improvements.

[0095] Furthermore, since there are many types of hydraulic breakers, it is possible to pre-set multiple first setting conditions tailored to each hydraulic breaker, allowing the operator of the work machine 1 to select which of the multiple first setting conditions to use.

[0096] Specifically, the memory unit (not shown) of the work machine 1 described earlier is assumed to be a memory unit that stores multiple first setting conditions, and the display unit (not shown) described earlier is a touch panel display unit that functions as a selection unit that allows the user to select which of the multiple first setting conditions to use.

[0097] Furthermore, the memory unit may be configured such that each first setting condition, which is pre-stored, includes the circuit breaker usage conditions (e.g., the circuit breaker model name) and a temperature threshold corresponding to those usage conditions, and the operator selects the circuit breaker usage conditions (e.g., the circuit breaker model name) on a touch panel selection unit, and a temperature threshold corresponding to those usage conditions is selected.

[0098] Furthermore, the hydraulic control unit (CTU) should perform the control (processing in S14) to switch from the merging supply control (see Figure 7) described earlier to the single-flow supply control (see Figure 8) according to the first setting condition selected from among several first setting conditions.

[0099] <<Second Embodiment>> Next, with reference to Figure 9, a work machine 1 that can use a breaker (hydraulic breaker 431) on the tip attachment 43 of the second embodiment of the present invention, and a hydraulic control device CTU for the work machine 1 will be described.

[0100] Figure 9 is a flowchart showing the control performed by the hydraulic control device CTU of the second embodiment of the present invention when using the hydraulic breaker 431, and is a flowchart corresponding to Figure 5.

[0101] Furthermore, the control performed by the hydraulic control device CTU in the second embodiment when using the hydraulic breaker 431 is basically the same as the control performed by the hydraulic control device CTU in the first embodiment when using the hydraulic breaker 431.

[0102] In Figure 9, the same step numbers as in the flowchart of Figure 5 are used for the same processes as the control performed by the hydraulic control device CTU in the first embodiment when using the hydraulic breaker 431. Below, we will mainly explain the differences from the first embodiment, and may omit explanations of points that are the same as the first embodiment.

[0103] In the second embodiment, a second setting condition is provided, which includes an operating time threshold that allows continuous operation of the breaker, in order to suppress the temperature rise of the hydraulic fluid and protect the hydraulic breaker 431. This second setting condition is pre-registered in the memory unit (not shown) described earlier.

[0104] (S20) Specifically, in addition to the steps shown in Figure 5, a step S20 is added as shown in Figure 9. In S20, if the continuous operation of the breaker (hydraulic breaker 431) is within the operating time threshold (S20 is YES), the process proceeds to S16 as explained earlier.

[0105] On the other hand, the hydraulic control unit CTU, in accordance with a second setting condition which includes an operating time threshold that allows continuous operation of the breaker (hydraulic breaker 431), controls the system to stop the operation of the breaker by stopping the supply of hydraulic fluid to the second hydraulic circuit HC2 when the continuous operation of the breaker exceeds the operating time threshold (S20 is NO).

[0106] Specifically, although the circuit breaker has not been shut off, the series of processes is terminated, similar to the case where S16 is YES in the first embodiment.

[0107] In other words, the hydraulic control unit (CTU) monitors whether the next breaker activation operation has been performed while in the normal standby state described at the start of the flowchart in Figure 5, and the operator of the work machine 1 performs the breaker activation operation again after a short delay.

[0108] Furthermore, before the operating time threshold is exceeded, in order to inform the operator of the work machine 1 that the operating time threshold will soon be exceeded and the circuit breaker will be shut off, a countdown to the circuit breaker shutdown may be displayed on the display unit (not shown) described earlier.

[0109] In other words, the work machine 1 may be equipped with a display unit (not shown) capable of displaying the time until the circuit breaker stops, according to the second setting condition (operating time threshold).

[0110] Furthermore, since there are many types of hydraulic breakers, similar to the first setting conditions, multiple second setting conditions tailored to each hydraulic breaker may be set in advance so that the operator of the work machine 1 can select which of the multiple second setting conditions to use.

[0111] Specifically, the memory unit (not shown) of the work machine 1 described earlier is assumed to be a memory unit that stores multiple second setting conditions, and the display unit (not shown) described earlier is a touch panel display unit that functions as a selection unit that allows the user to select which of the multiple second setting conditions to use.

[0112] Furthermore, the second setting conditions, which are pre-stored in the memory unit, may include the circuit breaker usage conditions (e.g., the circuit breaker model name) and an operating time threshold corresponding to the usage conditions. The operator may then select the circuit breaker usage conditions (e.g., the circuit breaker model name) on a touch panel selection unit, and an operating time threshold corresponding to the usage conditions may be selected.

[0113] Furthermore, the hydraulic control unit (CTU) should perform the S20 process described earlier (control to stop the operation of the breaker) according to the second setting condition selected from among several second setting conditions.

[0114] According to the second embodiment of the work machine 1 described above, when the continuous operating time of the breaker exceeds the operating time threshold, the hydraulic control unit (CTU) stops the breaker. This allows the operator to realize that they have been operating the breaker for too long, enabling appropriate protection of the breaker and suppression of the rise in the temperature of the hydraulic fluid.

[0115] <<Third Embodiment>> Next, with reference to Figure 10, a work machine 1 that can use a breaker (hydraulic breaker 431) on the tip attachment 43 of the third embodiment according to the present invention, and a hydraulic control device CTU for the work machine 1 will be described.

[0116] Figure 10 is a flowchart showing the control performed by the hydraulic control device CTU of the third embodiment of the present invention when using the hydraulic breaker 431, and is a flowchart corresponding to Figure 9.

[0117] Furthermore, the control performed by the hydraulic control device CTU of the third embodiment when using the hydraulic breaker 431 is basically the same as the control performed by the hydraulic control device CTU of the second embodiment when using the hydraulic breaker 431.

[0118] In Figure 10, the same step numbers as in the flowchart of Figure 9 are used for the same processes as the control performed by the hydraulic control device CTU in the second embodiment when using the hydraulic breaker 431. Below, we will mainly explain the differences from the second embodiment, and may omit explanations of points that are the same as the second embodiment.

[0119] In the third embodiment, if the operation of the breaker (hydraulic breaker 431) is stopped according to the second setting condition described in the second embodiment, a third setting condition is provided, which is a time condition until restarting is permitted.

[0120] Specifically, in the third embodiment, the third setting condition includes a first downtime threshold, which is a time condition for allowing restart, and this third setting condition is pre-registered in the storage unit (not shown) described earlier.

[0121] (S30) Specifically, in addition to the steps shown in Figure 9, a step S30 is added as shown in Figure 10. In S30, after stopping the operation of the breaker according to the second setting conditions described in the second embodiment (S20 is NO), the hydraulic control unit CTU determines whether the breaker's stop time is within a first stop time threshold, which is the time until restarting is permitted.

[0122] Then, if the breaker's downtime is within the first downtime threshold (S30 is YES), the hydraulic control unit CTU continues the determination in S30 and waits for the breaker's downtime to exceed the first downtime threshold.

[0123] On the other hand, the hydraulic control unit CTU, when the breaker's downtime exceeds the first downtime threshold, The system enables the supply of hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 to the second hydraulic circuit HC2, permits the restart of the breaker, and proceeds to S10 to determine whether the operator has performed the breaker activation operation.

[0124] In the second embodiment, after stopping the operation of the circuit breaker according to the second setting condition (S20 is NO), the downtime until the circuit breaker is restarted is left to the operator, so variations in the downtime until restart are likely to occur.

[0125] On the other hand, with the work machine 1 of the third embodiment described above, since the time until restart is fixed, it is possible to avoid situations where the downtime until restart becomes too short.

[0126] <<Fourth Embodiment>> Next, with reference to Figure 11, a work machine 1 that can use a breaker (hydraulic breaker 431) on the tip attachment 43 of the fourth embodiment according to the present invention, and the hydraulic control device CTU of the work machine 1 will be described.

[0127] Figure 11 is a flowchart showing the control performed by the hydraulic control device CTU of the fourth embodiment of the present invention when using the hydraulic breaker 431, and is a flowchart corresponding to Figure 10.

[0128] Furthermore, the control performed by the hydraulic control device CTU of the fourth embodiment when using the hydraulic breaker 431 is basically the same as the control performed by the hydraulic control device CTU of the third embodiment when using the hydraulic breaker 431.

[0129] In Figure 11, the same step numbers as in the flowchart of Figure 10 are used for the same processing as the control performed by the hydraulic control device CTU in the third embodiment when using the hydraulic breaker 431. Below, we will mainly explain the differences from the third embodiment, and may omit explanations of points that are the same as the third embodiment.

[0130] As described in the first embodiment, the hydraulic fluid supplied to the hydraulically driven drive units other than the breaker, such as a pair of hydraulic motors (not shown) provided on the lower traveling body 10, a slewing motor (not shown) that rotates the upper slewing body 30, the boom cylinder 41A, the arm cylinder 42A, and the tip attachment cylinder 43A, all return to the tank TK via the oil cooler OC.

[0131] Therefore, after stopping the operation of the breaker according to the second setting conditions described in the second embodiment (S20 is NO), if a hydraulically driven drive unit other than the breaker is driven, for example, to drive the lower traveling body 10 in order to change the position of the work machine 1, the hydraulic fluid supplied for that purpose is cooled by the oil cooler OC and returned to the tank TK.

[0132] Therefore, the hydraulic fluid will be cooled more than when the work machine 1 is waiting in the normal standby state described at the start of the flowchart in Figure 5.

[0133] Therefore, in the fourth embodiment, the third setting condition includes a second stop time threshold, which is a shorter time than the first stop time threshold described in the third embodiment, which is the time condition until restart is permitted when a hydraulically driven drive unit other than the breaker is being driven. Furthermore, this third setting condition, including the second stop time threshold, is also pre-registered in the memory unit (not shown) described earlier.

[0134] (S40) In S40, the hydraulic control unit CTU monitors whether the drive unit other than the breaker has started operating after stopping the breaker operation according to the second setting condition described in the second embodiment. If the drive unit other than the breaker has not started operating (S40 is NO), the process proceeds to S30, as in the third embodiment. If the result of S30 is YES, the process returns to S40.

[0135] On the other hand, if, after the hydraulic control unit CTU stops the operation of the breaker in accordance with the second setting conditions described in the second embodiment, the drive unit other than the breaker is operated (S40 is YES), the process proceeds to S41.

[0136] (S41) In S41, if the breaker's downtime is within the second downtime threshold (S41 is YES), the hydraulic control unit CTU continues the determination in S41 and waits for the breaker's downtime to exceed the second downtime threshold.

[0137] On the other hand, if the breaker's downtime exceeds the second downtime threshold (S41 is NO), the hydraulic control unit CTU enables the supply of hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 to the second hydraulic circuit HC2, permits the breaker to restart, and proceeds to S10 to determine whether or not the operator has performed the breaker activation operation.

[0138] Thus, in the working machine 1 of the fourth embodiment, when the operation of the breaker is stopped according to the second setting conditions described in the second embodiment, and when a hydraulically driven drive unit other than the breaker is being driven, the hydraulic control device CTU allows the supply of hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker, because the cooling of the hydraulic fluid progresses easily, and the second stop time threshold, which is shorter than the first stop time threshold, is exceeded.

[0139] Therefore, the time required for restarting the machine, adjusted to the cooling state of the hydraulic fluid, can be shortened, thereby improving work efficiency.

[0140] <<Fifth Embodiment>> Next, with reference to Figure 12, a work machine 1 that can use a breaker (hydraulic breaker 431) on the tip attachment 43 of the fifth embodiment according to the present invention, and a hydraulic control device CTU for the work machine 1 will be described.

[0141] Figure 12 is a flowchart showing the control performed by the hydraulic control device CTU of the fifth embodiment of the present invention when using the hydraulic breaker 431, and is a flowchart corresponding to Figure 10.

[0142] Furthermore, the control performed by the hydraulic control device CTU of the fifth embodiment when using the hydraulic breaker 431 is basically the same as the control performed by the hydraulic control device CTU of the third embodiment when using the hydraulic breaker 431.

[0143] In Figure 12, the same step numbers as in the flowchart of Figure 10 are used for the same processing as the control performed by the hydraulic control device CTU in the third embodiment when using the hydraulic breaker 431. Below, we will mainly explain the differences from the third embodiment, and may omit explanations of points that are the same as the third embodiment.

[0144] In the fifth embodiment, when the breaker is stopped operating according to the second setting condition, flow rate increase control is performed to increase the flow rate of at least one of the hydraulic fluid supplied from the first hydraulic pump P1 to the first hydraulic circuit HC1, or the hydraulic fluid supplied from the second hydraulic pump P2 to the third hydraulic circuit HC3, to a level higher than the flow rate in the normal standby state, thereby enabling efficient cooling of the hydraulic fluid.

[0145] Accordingly, the third setting condition includes a third downtime threshold that is shorter than the first downtime threshold described in the third embodiment, which is the time condition until restart is permitted. Furthermore, this third setting condition, including the third stop time threshold, is also pre-registered in the memory unit (not shown) described earlier.

[0146] (S50) Therefore, in S50, instead of S30 in the third embodiment, if the breaker's stop time is within the third stop time threshold (S50 is YES), the hydraulic control device CTU continues the determination in S50 and waits for the breaker's stop time to exceed the third stop time threshold.

[0147] On the other hand, the hydraulic control unit CTU, when the breaker's downtime exceeds the third downtime threshold, The system enables the supply of hydraulic fluid from the first hydraulic pump P1 and the second hydraulic pump P2 to the second hydraulic circuit HC2, permits the restart of the breaker, and proceeds to S10 to determine whether the operator has performed the breaker activation operation.

[0148] (S51) Then, in order to make the determination in S50 based on the third setting condition including the third stop time threshold, in S51, if the hydraulic control device CTU stops the operation of the breaker in accordance with the second setting condition, it performs flow rate increase control to make at least one of the flow rates of hydraulic fluid supplied from the first hydraulic pump P1 to the first hydraulic circuit HC1 which returns to the tank TK via the oil cooler without going through the breaker, or the flow rate of hydraulic fluid supplied from the second hydraulic pump P2 to the third hydraulic circuit HC3 which returns to the tank TK via the oil cooler without going through the breaker, greater than the flow rate in the normal standby state.

[0149] Specifically, for example, the hydraulic control unit (CTU) can maintain the output (rotational speed) of the first hydraulic pump P1 and the second hydraulic pump P2 when supplying hydraulic fluid to the second hydraulic circuit HC2 (i.e., the breaker), and switch each valve to supply hydraulic fluid to the first hydraulic circuit HC1 and the third hydraulic circuit HC3, thereby preventing hydraulic fluid from being supplied to the breaker and stopping the breaker.

[0150] Furthermore, even if the flow rate of the hydraulic fluid in either the first hydraulic circuit HC1 or the third hydraulic circuit HC3 is the same as the flow rate in the normal standby state, if the flow rate of the hydraulic fluid in the other circuit is greater than the flow rate in the normal standby state, the cooling efficiency will be higher, so either one is sufficient.

[0151] However, if the flow rates of the hydraulic fluid in both the first hydraulic circuit HC1 and the third hydraulic circuit HC3 are higher than the flow rates in the normal standby state, the cooling efficiency will be further improved. Therefore, from the standpoint of cooling efficiency, it is preferable that the flow rates of the hydraulic fluid in both the first hydraulic circuit HC1 and the third hydraulic circuit HC3 are higher than the flow rates in the normal standby state.

[0152] Thus, in the fifth embodiment, when the hydraulic control device CTU stops the operation of the breaker according to the second setting condition, in order to improve the cooling efficiency of the hydraulic fluid, it performs flow rate increase control by increasing the flow rate of at least one of the hydraulic fluid supplied from the first hydraulic pump P1 to the first hydraulic circuit HC1, or the hydraulic fluid supplied from the second hydraulic pump P2 to the third hydraulic circuit HC3, to a level higher than the flow rate in the normal standby state.

[0153] Furthermore, as described above, when the breaker is stopped in accordance with the second setting condition, and no other hydraulically driven drive unit is being driven, if the hydraulic control device CTU is performing flow rate increase control, the cooling efficiency of the hydraulic fluid is improved. Therefore, when the third stop time threshold, which is shorter than the first stop time threshold described in the third embodiment, is exceeded, it becomes possible to supply hydraulic fluid to the second hydraulic circuit HC2 and permit the breaker to restart.

[0154] In the fifth embodiment, the example was described in which the hydraulic control unit CTU automatically performs the process in step S51. However, when S20 becomes NO and the breaker is stopped, the operator may instruct the hydraulic control unit CTU to perform the process in step S51. In response to this instruction, the hydraulic control unit CTU may perform the process corresponding to S51 and perform the process in S50 when the breaker is restarted.

[0155] In other words, the operator operating the work machine 1 may be able to perform an operation to switch from the control of the hydraulic control device CTU described in the third embodiment to the control of the hydraulic control device CTU as described in the fifth embodiment, for example, when the operation of the breaker is stopped according to the second setting condition.

[0156] The present invention has been described above based on specific embodiments, but the present invention is not limited to the above embodiments. The present invention also includes modifications and improvements to the above embodiments, which will be clear to those skilled in the art from the description of the claims.

[0157] Furthermore, the following additional information is disclosed regarding the above embodiments. [Note 1] It is a work machine, The aforementioned work machine is Lower running body and An upper slewing body is provided so as to be rotatable relative to the lower traveling body, A work mechanism is provided on the upper rotating body, and a breaker can be used as the tip attachment, A tank for storing hydraulic fluid is provided in the upper rotating body, A first hydraulic circuit returns the hydraulic fluid from the tank to the tank via an oil cooler without passing through the breaker, A first hydraulic pump capable of supplying hydraulic fluid from the tank to the first hydraulic circuit, A second hydraulic circuit is used when the aforementioned breaker is used, and returns the hydraulic fluid from the tank to the tank via the breaker without passing through the oil cooler. A second hydraulic pump capable of supplying the hydraulic fluid from the tank to the second hydraulic circuit, A switching valve that switches the supply destination of the hydraulic fluid from the first hydraulic pump to the first hydraulic circuit or the second hydraulic circuit, The system includes a hydraulic control device that controls the supply of the hydraulic fluid, A work machine that, when using the breaker, the hydraulic control device switches the switching valve according to a first setting condition for switching the switching valve, and switches from combined supply control, which supplies hydraulic fluid from the first hydraulic pump and the second hydraulic pump to the second hydraulic circuit, to single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump to the first hydraulic circuit and the hydraulic fluid from the second hydraulic pump to the second hydraulic circuit. [Note 2] The first setting condition includes a temperature threshold for the temperature of the hydraulic fluid. The aforementioned work machine is equipped with a temperature measuring unit for measuring the temperature of the hydraulic fluid, The hydraulic control device, as described in Appendix 1, performs control to switch from the combined flow supply control to the single flow supply control when the temperature of the hydraulic fluid measured by the temperature measuring unit exceeds the temperature threshold. [Note 3] The work machine described in Appendix 1 or Appendix 2, which is equipped with a display unit capable of indicating that the control has switched from the combined supply control to the single-flow supply control. [Note 4] The work machine according to any one of the appendices 1 to 3, wherein the hydraulic control device performs a single-flow supply flow rate increase control, which increases the flow rate of the hydraulic fluid supplied from the first hydraulic pump to the first hydraulic circuit to a higher amount than the flow rate in the normal standby state when performing the single-flow supply control. [Note 5] The aforementioned work machine is A storage unit that stores a plurality of the above-mentioned first setting conditions, It includes a selection unit that allows the user to select which of the multiple first setting conditions to use, Each of the above-mentioned first setting conditions is a working machine as described in Appendix 2, which includes the operating conditions of the breaker and the temperature threshold that matches the operating conditions. [Note 6] The hydraulic control device controls the operation of the breaker by stopping the supply of the hydraulic fluid to the second hydraulic circuit and stopping the operation of the breaker when the continuous operation of the breaker exceeds the operating time threshold, in accordance with a second setting condition which includes an operating time threshold that allows the continuous operation of the breaker. This is the operation control device according to any one of the appendices 1 to 5. [Note 7] The aforementioned work machine is A storage unit that stores multiple second setting conditions, It includes a selection unit that allows the user to select which of the multiple second setting conditions to use, Each of the aforementioned second setting conditions is a work machine as described in Appendix 6, which includes the operating conditions of the breaker and the operating time threshold that matches the operating conditions. [Note 8] The hydraulic control device, when it stops the operation of the breaker in accordance with the second setting condition, enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker in accordance with a third setting condition which includes a first stop time threshold that is a time condition until restart is permitted, when the first stop time threshold is exceeded, as described in Appendix 6 or Appendix 7 of the working machine. [Note 9] The third setting condition includes a second stop time threshold that is shorter than the first stop time threshold, which is the time condition for allowing restart when a hydraulically driven drive unit other than the breaker is being driven. The hydraulic control device, when the operation of the breaker is stopped in accordance with the second setting condition, and when a hydraulically driven drive unit other than the breaker is being driven, allows the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker, as described in Appendix 8 of the working machine. [Note 10] When the hydraulic control device stops the operation of the breaker in accordance with the second setting condition, it performs flow rate increase control to increase the flow rate of at least one of the hydraulic fluid flow rate supplied from the first hydraulic pump to the first hydraulic circuit, or the flow rate of hydraulic fluid supplied from the second hydraulic pump to the third hydraulic circuit that returns to the tank via the oil cooler without passing through the breaker, to a level higher than the flow rate in the normal standby state. The third setting condition includes a third stop time threshold that is shorter than the first stop time threshold, which is the time condition for allowing restart when flow rate increase control is being performed. The hydraulic control device, when it has stopped the operation of the breaker in accordance with the second setting condition and is performing the flow rate increase control, enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker, as described in Appendix 8 of the working machine. [Note 11] A hydraulic control device for a work machine that can use a breaker as an end attachment, When using the breaker, the hydraulic control device switches from a single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump to a second hydraulic circuit that returns hydraulic fluid from the first hydraulic pump to a tank that stores the hydraulic fluid, via an oil cooler without passing through the breaker, to a single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump and the second hydraulic pump to the tank, via the breaker without passing through the oil cooler, according to a first setting condition. [Note 12] The first setting condition includes a temperature threshold for the temperature of the hydraulic fluid, The hydraulic control device described in Appendix 11, which performs control to switch from the combined flow supply control to the single flow supply control when the temperature of the hydraulic fluid exceeds the temperature threshold. [Note 13] The hydraulic control device according to Appendix 11 or Appendix 12, wherein the hydraulic control device controls the flow rate of the hydraulic fluid supplied from the first hydraulic pump to the first hydraulic circuit to be greater than the flow rate in the normal standby state when performing the single-flow supply control. [Note 14] Multiple of the above-mentioned first setting conditions are provided, The hydraulic control device switches from the combined flow supply control to the single flow supply control according to a first setting condition selected from among a plurality of first setting conditions. Each of the above-mentioned first setting conditions is a hydraulic control device as described in Appendix 12, which includes the operating conditions of the breaker and the temperature threshold corresponding to the operating conditions. [Note 15] The hydraulic control device according to any one of the appendices 11 to 14, wherein the hydraulic control device controls the stopping of operation of the breaker by stopping the supply of the hydraulic fluid to the second hydraulic circuit when the continuous operation of the breaker exceeds the operating time threshold, in accordance with a second setting condition which includes an operating time threshold that permits continuous operation of the breaker. [Note 16] Multiple second setting conditions are provided, The hydraulic control device performs control to stop the operation of the breaker according to a second setting condition selected from among a plurality of second setting conditions. Each of the aforementioned second setting conditions is a hydraulic control device as described in Appendix 15, which includes the operating conditions of the breaker and the operating time threshold corresponding to the operating conditions. [Note 17] The hydraulic control device according to Appendix 15 or Appendix 16, wherein when the operation of the breaker is stopped in accordance with the second setting condition, the hydraulic control device enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker in accordance with a third setting condition which includes a first stop time threshold that is a time condition until restart is permitted, when the first stop time threshold is exceeded. [Note 18] The third setting condition includes a second stop time threshold that is shorter than the first stop time threshold, which is the time condition for allowing restart when a hydraulically driven drive unit other than the breaker is being driven. The hydraulic control device described in Appendix 17, which, when the operation of the breaker is stopped in accordance with the second setting condition, and the drive unit driven by hydraulics other than the breaker is being driven, enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker when the second stop time threshold is exceeded. [Note 19] When the hydraulic control device stops the operation of the breaker in accordance with the second setting condition, it performs flow rate increase control to increase the flow rate of at least one of the hydraulic fluid flow rate supplied from the first hydraulic pump to the first hydraulic circuit, or the flow rate of hydraulic fluid supplied from the second hydraulic pump to the third hydraulic circuit that returns to the tank via the oil cooler without passing through the breaker, to a flow rate higher than the flow rate in the normal standby state. The third setting condition includes a third stop time threshold that is shorter than the first stop time threshold, which is the time condition for allowing restart when flow rate increase control is being performed. The hydraulic control device described in Appendix 17, which, when the operation of the breaker is stopped in accordance with the second setting condition and the flow rate increase control is being performed, enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker when the third stop time threshold is exceeded. [Explanation of Symbols]

[0158] 1...Working machine, 10...Lower traveling body, 20...Slewing section, 30...Upper slewing body, 31...Operator's cab, 32...Machine room, 40...Working mechanism, 41...Boom, 41A...Boom cylinder, 42...Arm, 42A...Arm cylinder, 43...End attachment, 43A...End attachment cylinder, 431...Hydraulic breaker, CTU...Hydraulic control unit, EG...Power source, HC1 ...1st hydraulic circuit, HC2...2nd hydraulic circuit, HC3...3rd hydraulic circuit, OC...oil cooler, OPS...breaker control unit, P1...1st hydraulic pump, P2...2nd hydraulic pump, PS1...1st hydraulic sensor, PS2...2nd hydraulic sensor, TK...tank, TM...temperature measurement unit, V1...1st unload valve, V2...2nd unload valve, VC1...combination switching valve, VC2...breaker switching valve

Claims

1. It is a work machine, The aforementioned work machine is Lower running body and An upper slewing body is provided so as to be rotatable relative to the lower traveling body, A work mechanism is provided on the upper rotating body, and a breaker can be used as the tip attachment, A tank for storing hydraulic fluid is provided in the upper rotating body, A first hydraulic circuit returns the hydraulic fluid from the tank to the tank via an oil cooler without passing through the breaker, A first hydraulic pump capable of supplying hydraulic fluid from the tank to the first hydraulic circuit, A second hydraulic circuit is used when the aforementioned breaker is used, and returns the hydraulic fluid from the tank to the tank via the breaker without passing through the oil cooler. A second hydraulic pump capable of supplying the hydraulic fluid from the tank to the second hydraulic circuit, A switching valve that switches the supply destination of the hydraulic fluid from the first hydraulic pump to the first hydraulic circuit or the second hydraulic circuit, The system includes a hydraulic control device that controls the supply of the hydraulic fluid, A work machine that, when using the breaker, the hydraulic control device switches the switching valve according to a first setting condition for switching the switching valve, and switches from combined supply control, which supplies hydraulic fluid from the first hydraulic pump and the second hydraulic pump to the second hydraulic circuit, to single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump to the first hydraulic circuit and also supplies the hydraulic fluid from the second hydraulic pump to the second hydraulic circuit.

2. The first setting condition includes a temperature threshold for the temperature of the hydraulic fluid. The aforementioned work machine is equipped with a temperature measuring unit for measuring the temperature of the hydraulic fluid, The working machine according to claim 1, wherein the hydraulic control device performs control to switch from the combined supply control to the single-flow supply control when the temperature of the hydraulic fluid measured by the temperature measuring unit exceeds the temperature threshold.

3. The work machine according to claim 1 or claim 2, wherein the work machine is equipped with a display unit capable of indicating that it has switched from the combined supply control to the single-flow supply control.

4. The working machine according to claim 1 or 2, wherein the hydraulic control device performs a single-flow supply flow rate increase control, which increases the flow rate of the hydraulic fluid supplied from the first hydraulic pump to the first hydraulic circuit to a higher amount than the flow rate in the normal standby state, when performing the single-flow supply control.

5. The aforementioned work machine is A storage unit that stores a plurality of the above-mentioned first setting conditions, It includes a selection unit that allows selecting which of the multiple first setting conditions to use, The working machine according to claim 2, wherein each of the first setting conditions includes the operating conditions of the circuit breaker and the temperature threshold corresponding to the operating conditions.

6. The work machine according to claim 1, wherein the hydraulic control device controls the operation of the breaker by stopping the supply of the hydraulic fluid to the second hydraulic circuit and stopping the operation of the breaker when the continuous operation of the breaker exceeds the operating time threshold, according to a second setting condition which includes an operating time threshold that allows the continuous operation of the breaker.

7. The aforementioned work machine is A storage unit that stores a plurality of the above-mentioned second setting conditions, It includes a selection unit that allows the user to select which of the multiple second setting conditions to use, The work machine according to claim 6, wherein each of the aforementioned second setting conditions includes the usage conditions of the circuit breaker and the operating time threshold that matches the usage conditions.

8. The hydraulic control device, when it stops the operation of the breaker in accordance with the second setting condition, enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker in accordance with a third setting condition which includes a first stop time threshold that is a time condition until restart is permitted, when the first stop time threshold is exceeded. This is the working machine according to claim 6 or claim 7.

9. The third setting condition includes a second stop time threshold that is shorter than the first stop time threshold, which is the time condition for allowing restart when a hydraulically driven drive unit other than the breaker is being driven. The work machine according to claim 8, wherein when the operation of the breaker is stopped in accordance with the second setting condition, and a hydraulically driven drive unit other than the breaker is being driven, the hydraulic control device enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker when the second stop time threshold is exceeded.

10. When the hydraulic control device stops the operation of the breaker in accordance with the second setting condition, it performs flow rate increase control to increase the flow rate of at least one of the hydraulic fluid flow rate supplied from the first hydraulic pump to the first hydraulic circuit, or the flow rate of hydraulic fluid supplied from the second hydraulic pump to the third hydraulic circuit that returns to the tank via the oil cooler without passing through the breaker, to a flow rate higher than the flow rate in the normal standby state. The third setting condition includes a third stop time threshold that is shorter than the first stop time threshold, which is the time condition for allowing restart when flow rate increase control is being performed. The working machine according to claim 8, wherein when the operation of the breaker is stopped in accordance with the second setting condition and the flow rate increase control is being performed, the hydraulic control device enables the supply of the hydraulic fluid to the second hydraulic circuit and permits the restart of the breaker when the third stop time threshold is exceeded.

11. A hydraulic control device for a work machine that can use a breaker as an end attachment, When using the breaker, the hydraulic control device switches from a single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump to a second hydraulic circuit that returns hydraulic fluid from the first hydraulic pump to a tank that stores the hydraulic fluid, via an oil cooler without passing through the breaker, to a single-flow supply control, which supplies hydraulic fluid from the first hydraulic pump and the second hydraulic pump to the tank, via the breaker without passing through the oil cooler, according to a first setting condition.

12. The first setting condition includes a temperature threshold for the temperature of the hydraulic fluid, The hydraulic control device according to claim 11, wherein the hydraulic control device performs control to switch from the combined flow supply control to the single flow supply control when the temperature of the hydraulic fluid exceeds the temperature threshold.

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