JP2017187144A - Working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working machine which can easily and properly adjust set pressure in a supply oil passage when working while exchanging a plurality of kinds of attachments.SOLUTION: A working machine comprises: an electromagnetic proportional relief valve 35 for controlling pressure in a zone oil passage 31 from a first attachment control valve for controlling the supply of hydraulic pressure to a first attachment A1 up to a hydraulic pressure takeout part C1; an attachment hydraulic pressure setting switch S1 for designating a set value of the pressure in the zone oil passage 31 according to a kind of the attachment; and a control device CU for electrically controlling the electromagnetic proportional relief valve 35 so that the pressure in the zone oil passage 31 reaches a set value. The set value of the pressure in the zone oil passage 31 at the exchange of the attachment is designated by operation of the attachment hydraulic pressure setting switch S1 by a worker.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a work machine in which various attachments such as a breaker are detachably attached to an arm provided on a vehicle body.

  As such a working machine, an excavator loader, a power shovel (backhoe), and the like used when excavating the ground or moving excavated earth and sand are widely known. Such work machines are configured so that various attachments such as buckets, blades, chip breakers (also simply referred to as “breakers”), auger devices, and the like can be attached to and detached from the tip of an arm that is swingable up and down on the vehicle body. By attaching and detaching the attachment according to the work purpose, one work machine can be used for multiple purposes and multiple functions (for example, see Patent Document 1).

JP 2005-336767 A

  In such a work machine, when replacing the attachment, it is necessary to adjust the pressure in the supply oil passage for supplying hydraulic oil to the attachment to be an appropriate set pressure according to the type of attachment. is there.

  Conventionally, such adjustment of the set pressure in the supply oil passage is performed by, for example, an operator using a hexagon wrench to adjust the adjustment screw of the port relief valve provided in the control valve while looking at a pressure gauge installed in the supply oil passage. It was done manually, such as turning and adjusting with a tool such as. Therefore, the work is complicated and troublesome. In addition, because of manual work, the adjustment of the set pressure may be insufficient or the adjustment may be forgotten, which may cause the attachment to not operate normally.

  This invention is made in view of such a subject, and provides the working machine which can perform the adjustment operation | work of the setting pressure in the supply oil path in the case of replacing | attaching an attachment simply and accurately. Objective.

In order to achieve the above object, a working machine according to the present invention (for example, a power shovel 1 in the embodiment) is configured such that a plurality of types of attachments that are operated by receiving hydraulic pressure are selectively detachable. A hydraulic pressure take-out portion provided for supplying oil pressure to the attachment, a hydraulic pressure source for supplying oil pressure (for example, the main hydraulic pump P1 in the embodiment), and the hydraulic pressure take-out portion from the hydraulic pressure source A supply oil path for supplying oil pressure to the attachment, and a supply control valve (for example, the first attachment control valve V11 in the embodiment) provided in the supply oil path for controlling supply of the oil pressure to the attachment; In the supply oil passage, the pressure in the take-out section oil passage (for example, the section oil passage 31 in the embodiment) from the supply control valve to the hydraulic pressure take-out portion is An electromagnetic pressure control valve to be controlled (for example, an electromagnetic proportional relief valve 35 in the embodiment) and a set value specifying means for specifying a set value of the pressure in the extraction side section oil passage according to the type of the attachment (for example, implementation) Pressure control valve control means (for example, implementation) for electrically controlling the electromagnetic pressure control valve so that the pressure in the extraction side section oil passage becomes a specified set value. And a control unit CU) in the form.

  In the work machine configured as described above, the oil is branched from the extraction side section oil passage and extends to an oil tank (for example, the hydraulic oil tank T in the embodiment), and the return oil from the attachment is passed through the supply control valve without passing through the supply control valve. A branch return oil passage for returning to the oil tank; an opening / closing solenoid valve (for example, an electromagnetic control valve 38 in the embodiment) provided in the branch return oil passage and operating to open and close the branch return oil passage; An opening / closing solenoid valve control means for controlling the opening / closing operation of the opening / closing solenoid valve (for example, the control unit CU in the embodiment) is preferably provided.

  According to the work machine according to the present invention configured as described above, the electromagnetic pressure control valve is electrically connected by the pressure control valve control means so that the pressure in the extraction side section oil passage becomes a specified set value. Since the set value of the pressure at this time is specified by the set value specifying means, the adjustment work of the set pressure in the extraction side section oil passage when replacing the attachment is simple and accurate. Can be done.

  In the work machine configured as described above, a branch return oil passage for returning the return oil from the attachment to the oil tank without going through the supply control valve, and an opening / closing solenoid valve that operates to open and close the branch return oil passage; If the configuration includes an opening / closing solenoid valve control means for controlling the opening / closing operation of the opening / closing solenoid valve, the return oil from the attachment is returned to the oil tank without going through the supply control valve, and the supply control valve It is also possible to easily and accurately perform the switching operation with the case of returning to the oil tank.

It is a perspective view which shows the power shovel to which this invention is applied. It is a block diagram which shows the outline of the hydraulic control system of the said power shovel. It is a hydraulic circuit diagram which shows the structure of the hydraulic pressure adjustment circuit part for 1st attachment of the said power shovel. It is a hydraulic circuit diagram which shows the structure of the hydraulic adjustment circuit part for the 2nd and 3rd attachment of the said power shovel.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a crawler type excavator 1 to which the present invention is applied, and FIG. 2 shows a schematic configuration of a hydraulic control system for controlling the operation of a hydraulic actuator of the power shovel 1. The schematic configuration of the power shovel 1 will be described first with reference to FIGS. 1 and 2. For convenience of explanation, the arrow directions shown in FIG. 1 are defined as front and rear, left and right, and up and down.

  As shown in FIG. 1, the excavator 1 includes a traveling device 4 configured to include traveling mechanisms 3 and 3 on the left and right sides of a substantially H-shaped traveling cart 2 in plan view, and a rear portion of the traveling cart 2 that swings up and down. A blade 5 that is movably provided, a swivel base 6 that is turnable on the top of the traveling carriage 2, an excavator mechanism 7 that is provided at the front of the swivel base 6, and an upper part of the swivel base 6. And an operator cabin 8 for boarding an operator.

The pair of left and right traveling mechanisms 3, 3 includes a driving sprocket wheel 9 provided at the left and right front portions of the traveling carriage 2, an idler wheel 10 provided at the left and right rear portions of the traveling carriage 2, a driving sprocket wheel 9 and an idler. The crawler belt 11 is wound around the wheel 10. Of the pair of left and right traveling mechanisms 3, 3, the traveling mechanism 3 provided on the right side of the traveling carriage 2 includes a hydraulically driven right traveling motor 9 </ b> R that drives the driving sprocket wheel 9. The traveling mechanism 3 provided on the left side of the traveling carriage 2 is provided with a hydraulically driven left traveling motor 9L that drives the driving sprocket wheel 9. The blade 5 is oscillated by a hydraulically driven blade cylinder (not shown). The swivel base 6 is swung with respect to the traveling device 4 by a hydraulic drive swivel motor (not shown).

  The shovel mechanism 7 includes a boom 12 pivotably connected to the front portion of the swivel base 6 and an arm 13 pivotally connected to the tip end portion of the boom 12 so as to swing up and down within the swing surface of the boom 12. And a bucket 14 pivotally connected to the tip of the arm 13 so as to be swingable up and down. A hydraulically driven boom cylinder 15 is provided across the front portion of the swivel base 6 and the boom 12, and the boom 12 is oscillated by the boom cylinder 15. A hydraulically driven arm cylinder 16 is provided across the boom 12 and the arm 13, and the arm 13 is pivoted by the arm cylinder 16. A hydraulically driven bucket cylinder 17 is provided across the arm 13 and the bucket 14, and the bucket 14 is oscillated by the bucket cylinder 17.

  A detachable quick hitch mechanism (not shown) is provided at the tip of the arm 13, and the bucket 14 is configured to be attached to and detached from the tip of the arm 13 via this quick hitch mechanism. Yes. Further, by removing the bucket 14 from the tip of the arm 13, a plurality of types of hydraulically operated attachments can be attached to and detached from the tip of the arm 13 via a quick hitch mechanism. In the present embodiment, as shown in FIG. 2, three types of attachments of a first attachment A1, a second attachment A2, and a third attachment A3 can be used as detachable attachments. The first attachment A1 is an operating device such as a breaker that is driven to reciprocate by high-pressure and large-flowing hydraulic oil, and the second attachment A2 is a rotary that is driven to rotate forward and backward by high-pressure and medium-flowing hydraulic oil. The third attachment A3 is an actuator such as a tilt that is slidably driven by a high-pressure and small-flow hydraulic oil.

  The operator cabin 8 is formed in a substantially rectangular box shape, and is provided with an operator seat 18 for the operator to sit facing forward. On the left and right sides of the operator seat 18 are provided a right work operation lever 19 and a left work operation lever 20 for operating the blade 5, the swivel base 6, the excavator mechanism 7, and the attached attachment. Further, a right traveling operation lever 21 and a left traveling operation lever 22 for operating the traveling device 4 are provided in front of the operator seat 18. The right travel operation lever 21 is an operation lever for operating the right travel motor 9R, and the left travel operation lever 22 is an operation lever for operating the left travel motor 9L. Furthermore, an operation lever (not shown) for operating the quick hitch mechanism is also provided.

  In addition, various switches operated by an operator are provided around the operator seat 18. As such switches, FIG. 2 shows three types of switches: an attachment hydraulic pressure setting switch S1, a first attachment hydraulic oil supply switch S2, and an auto tank operation switch S3. The attachment hydraulic pressure setting switch S1 is operated to designate a set value of pressure in the supply oil passage for supplying hydraulic oil to the attached attachment. Consists of devices. The first attachment hydraulic oil supply switch S2 is operated to supply hydraulic oil to the attached first attachment A1, and is provided at the top of the work operation levers 19 and 20, for example. The auto tank operation switch S3 is operated so that the hydraulic oil supplied to the attached first attachment A1 returns directly to the hydraulic oil tank T. For example, the auto tank operation switch S3 is displayed on the display panel. The icon can be selected from any of the three modes “ON”, “OFF”, and “AUTO”.

In the power shovel 1 configured as described above, the operator can operate the operator seat 1.
8, the right work operation lever 19 and the left work operation lever 20 are tilted back and forth, and the right travel operation lever 21 and the left travel operation lever 22 are tilted back and forth. The excavator 1 can be moved back and forth, or the excavator mechanism 7 or the like can be operated to perform work such as excavation.

  Specifically, the boom 12 is swung up and down by tilting the right operation lever 19 back and forth, and the bucket 14 is swung up and down by tilting left and right. The left work operation lever 20 is tilted back and forth to swing the arm 13 up and down and swing left and right to rotate the swivel 6 to the left and right. Further, the right traveling operation lever 21 is tilted forward to drive the right traveling motor 9R in the forward direction, the right traveling mechanism 3 is driven in the forward direction, and the backward traveling is performed by tilting in the backward direction. And drive in the reverse direction. Similarly, when the left travel operation lever 22 is tilted forward, the left travel motor 9L is driven forward to drive the left travel mechanism 3 in the forward direction, and reversely operated by tilting backward. Drive in the reverse direction.

  Next, in the power shovel 1, the configuration of the hydraulic control system that operates the hydraulic actuator and the like of the attached attachment in accordance with the operation of the operation levers 19 to 22 and the switches S1 to S3 will be described with reference to FIGS. This will be explained with additional reference. In addition, when each operation lever 19-22 is operated back and forth or left and right as described above, an operation signal corresponding to the operation direction and the operation amount is output.

  As shown in FIG. 2, the hydraulic control system includes a control unit CU to which operation signals from the operation levers 19 to 22 and the switches S1 to S3 are input, and an operation control to the hydraulic actuator by the control unit CU. A multi-manifold type (stacked type) control valve CV that controls oil supply, and a main hydraulic pump P1 and an auxiliary hydraulic pump P2 that are rotationally driven by the engine E are provided. The main hydraulic pump P1 and the auxiliary hydraulic pump P2 are configured to supply the hydraulic oil in the hydraulic oil tank T to the control valve CV via the supply oil passage.

  The control valve CV is a boom control valve V1 that performs hydraulic oil supply control to the boom cylinder 15, an arm control valve V2 that performs hydraulic oil supply control to the arm cylinder 16, and a bucket control that performs hydraulic oil supply control to the bucket cylinder 17. In addition to the valve V3 and the like, a first attachment control valve V11 and a second attachment control valve V12 are provided.

  The first attachment control valve V11 performs hydraulic oil supply control to the hydraulic actuator 71 of the first attachment A1 via the hydraulic pressure takeout part C1 for the first attachment A1 and the hydraulic pressure adjustment circuit part 30 for the first attachment. is there. The hydraulic pressure take-out part C1 has an outlet for the hydraulic oil supplied to the first attachment A1, and is connected to the hydraulic pressure receiving part D1 on the first attachment A1 side, so that the hydraulic pressure take-out part from the first attachment control valve V11. The oil passage on the vehicle body side extending to C1 is connected to the oil passage on the first attachment A1 side extending from the hydraulic actuator 71 to the hydraulic pressure receiving portion D1. The hydraulic pressure take-out part C1 may be configured to include a stop valve that automatically opens and closes the hydraulic pressure take-out port when the hydraulic pressure take-out part C1 is connected to and disconnected from the hydraulic pressure receiving part D1. It is good also as a thing provided with the stop valve which opens and closes (it is the same also about the hydraulic pressure taking parts C2 and C3 mentioned below).

The second / third attachment control valve V12 is a hydraulic fluid to the hydraulic actuator 72 of the second attachment A2 via the hydraulic pressure takeout portion C2 for the second attachment A2 and the hydraulic adjustment circuit portion 50 for the second / third attachment. Supply control is performed, or hydraulic oil supply control to the hydraulic actuator 73 of the third attachment A3 is performed via the hydraulic pressure takeout part C3 for the third attachment A3 and the hydraulic adjustment circuit part 50 for the second and third attachments. Is what you do. The hydraulic pressure takeout part C2 has an outlet for the hydraulic oil supplied to the second attachment A2, and is connected to the hydraulic pressure receiving part D2 on the second attachment A2 side, so that the hydraulic pressure takeout part from the second attachment control valve V12. The oil passage on the vehicle body side extending to C2 is connected to the oil passage on the second attachment A2 side extending from the hydraulic actuator 72 to the hydraulic pressure receiving portion D2. Similarly, the hydraulic pressure take-out part C3 has an outlet for the hydraulic oil supplied to the third attachment A3, and is connected to the hydraulic pressure receiving part D3 on the third attachment A3 side, so that the hydraulic pressure take-out part C3 is connected to the second attachment control valve V12. A vehicle body side oil passage extending to the hydraulic pressure takeout portion C3 and a third attachment A3 side oil passage extending from the hydraulic actuator 73 to the hydraulic pressure receiving portion D3 are connected to each other.

  As shown in FIG. 3, the first attachment hydraulic pressure adjustment circuit unit 30 includes a section oil passage 31 extending from the first attachment control valve V <b> 11 to the hydraulic pressure extraction unit C <b> 1, a pressure adjustment circuit unit 32, and an auto tank circuit unit 36. It is configured with. The section oil passage 31 constitutes a take-out section oil passage from the first attachment control valve V11 to the hydraulic pressure takeout section C1 among the supply oil paths extending from the hydraulic pumps P1 and P2 to the hydraulic pressure takeout section C1. It is composed of a side oil passage 31a and a return side oil passage 31b. The section oil passage 31 is connected to the oil passage 72 on the first attachment A1 side when the first attachment A1 is mounted (the oil passage 31a is connected to the oil passage 72a, and the oil passage 31b is connected to the oil passage 72b). ), Hydraulic oil (hydraulic pressure) can be supplied to the first attachment A1.

  The pressure adjusting circuit unit 32 includes an oil passage 33a branched from the supply-side oil passage 31a, an oil passage 33b branched from the return-side oil passage 31b, and the two oil passages 33a and 33b coupled to each other. An oil passage 33c extending to T is provided, check valves 34a and 34b are provided in the oil passages 33a and 33b, respectively, and an electromagnetic proportional relief valve 35 is provided in the oil passage 33c. The electromagnetic proportional relief valve 35 opens the oil passage 33c in response to an increase in the pressure in the section oil passage 31, and releases the hydraulic oil in the section oil passage 31 to the hydraulic oil tank T, so that the pressure in the section oil passage 31 is reduced. Pressure regulation is controlled so that the specified set value is obtained. This set value is designated by the operator operating the attachment hydraulic pressure setting switch S1. The control unit CU adjusts the current value input to the proportional solenoid of the electromagnetic proportional relief valve 35 based on the designated set value, and the electromagnetic proportional relief valve 35 can perform pressure regulation control according to the designated set value. Thus, the electromagnetic proportional relief valve 35 is controlled.

  The setting value can be set for the pressure in the oil passage 31a on the supply side of the section oil passage 31 or for the pressure in the oil passage 31b on the return side. In addition, when the first attachment A1 is detached (for example, when a switch for instructing removal of the first attachment A1 by the quick hitch mechanism is provided), the control unit CU is operated. Based on this, the electromagnetic proportional relief valve 35 is controlled to open the oil passage 33c so that the residual pressure in the section oil passage 31 is removed (the pressure becomes zero). By removing the residual pressure in the section oil passage 31, when the connection between the section oil passage 31 and the oil passage 72 on the first attachment A1 side is released, the hydraulic oil in the oil passages 31, 72 scatters. This can be prevented.

The auto tank circuit section 36 branches from the return side oil passage 31 b of the section oil passage 31 and extends to the hydraulic oil tank T, and an oil passage opening and closing provided in the branch return oil passage 37. The electromagnetic control valve 38 is configured. The electromagnetic control valve 38 operates so that the oil passage 37 can be opened and closed, and is controlled by the control unit CU based on each operation state of the first attachment hydraulic oil supply switch S2 and the auto tank operation switch S3. It is configured. Specifically, when the auto tank operation switch S3 is operated to “OFF”, the electromagnetic control valve 38 closes the oil passage 37 (the hydraulic oil flows from the section oil passage 31 side to the hydraulic oil tank T side). When the auto tank operation switch S3 is operated to “ON”, the electromagnetic control valve 38 opens the oil passage 37 (from the section oil passage 31 side to the hydraulic oil tank T side). To allow hydraulic fluid to flow). Further, when the auto tank operation switch S3 is operated to “auto”, the electromagnetic control valve 38 is controlled in accordance with the operation state of the first attachment hydraulic oil supply switch S2. That is, when the first attachment hydraulic oil supply switch S2 is operated to “ON” and hydraulic oil is supplied to the first attachment A1, the electromagnetic control valve 38 is controlled to open the oil passage 37, and the first When the one attachment hydraulic oil supply switch S2 is operated to be “off” and hydraulic oil is not supplied to the first attachment A1, the electromagnetic control valve 38 is controlled to close the oil passage 37. By controlling the electromagnetic control valve 38 so as to open the oil passage 37, the return oil from the first attachment A1 can be directly returned to the hydraulic oil tank without going through the first attachment control valve V11. . In addition, when using attachments other than a breaker as 1st attachment A1, the oil path 31b may be used as a supply side. In that case, when the auto tank operation switch S3 is operated to “auto”, the electromagnetic control valve 38 is controlled to close the oil passage 37.

As shown in FIG. 4, the second and third attachment hydraulic pressure adjustment circuit section 50 includes an oil passage switching electromagnetic control valve 55 and a section oil extending from the second and third attachment control valves V <b> 12 to the electromagnetic control valve 55. Road 51 (consisting of a left-rotating oil passage 51L that serves as a supply side when the second or third attachment A2 / A3 is rotated counterclockwise and a right-rotation oil passage 51R that serves as a supply side when rotating rightward. ), A section oil passage 52 (consisting of a left rotation oil passage 52L and a right rotation oil passage 52R) extending from the electromagnetic control valve 55 to the hydraulic pressure extraction portion C2, and from the electromagnetic control valve 55 to the hydraulic pressure extraction portion C3. An extending section oil path 53 (consisting of a left-rotating oil path 53L and a right-rotating oil path 53R) and a pressure adjusting circuit unit 54 are configured.

  The electromagnetic control valve 55 is controlled by the control unit CU so as to switch between a state in which the section oil passage 51 and the section oil passage 52 are connected and a state in which the section oil passage 51 and the section oil passage 53 are connected. It is configured. Although not shown, in the operator cabin 8, an attachment selection switch (for example, three icons displayed on a touch-type display panel (each icon is selected) to select which of the attachments A1 to A3 is to be mounted. For example, when the second attachment A2 is selected by the attachment selection switch, the control unit CU is connected to the section oil passage 51 and the control unit CU. When the third attachment A3 is selected so as to connect the section oil passage 52, the electromagnetic control valve 55 is configured to control the section oil passage 51 and the section oil passage 53 to be connected. .

  The section oil path 51 is a section oil path 52 that extends from the second and third attachment control valves V12 to the hydraulic pressure extraction section C2 among the supply oil paths extending from the hydraulic pumps P1 and P2 to the hydraulic pressure extraction section C2. Of the supply oil passage extending from the hydraulic pumps P1 and P2 to the hydraulic pressure take-out portion C3, and the take-out section oil passage from the second / third attachment control valve V12 to the hydraulic pressure take-out portion C3 together with the section oil passage 53 Configure. The section oil passage 52 is connected to the oil passage 74 on the second attachment A2 side when the second attachment A2 is mounted (the oil passage 52L is connected to the oil passage 74L, and the oil passage 52R is connected to the oil passage 74R). Furthermore, it is configured so that the hydraulic oil can be supplied to the second attachment A2 by being connected to the section oil passage 51 as well. The section oil passage 53 is connected to the oil passage 75 on the third attachment A3 side when the third attachment A3 is mounted (the oil passage 53L is connected to the oil passage 75L, and the oil passage 53R is connected to the oil passage 75R). Furthermore, it is configured to be able to supply hydraulic oil to the third attachment A3 by being connected to the section oil passage 51 as well.

The pressure adjusting circuit unit 54 operates by combining an oil passage 57a branched from the left rotation oil passage 51L, an oil passage 57b branched from the right rotation oil passage 51R, and these two oil passages 57a and 57b. An oil passage 57c extending to the oil tank T is provided. Check valves 58a and 58b are provided in the oil passages 57a and 57b, respectively, and an electromagnetic proportional relief valve 59 is provided in the oil passage 57c. The electromagnetic proportional relief valve 59 opens the oil passage 57c in response to an increase in the pressure in the section oil passage 51, and releases the hydraulic oil in the section oil passage 51 to the hydraulic oil tank T, so that the pressure in the section oil passage 51 is increased. Pressure regulation is controlled so that the specified set value is obtained. The specification of the set value and the control of the electromagnetic proportional relief valve 59 are the same as the specification of the set value and the control of the electromagnetic proportional relief valve 35 in the pressure regulating circuit section 32 described above, and the description thereof will be omitted. The point that the electromagnetic proportional relief valve 59 can be used to remove the residual pressure in the section oil passage 51 is the same as the electromagnetic proportional relief valve 35 described above, and a description thereof will be omitted.

  Next, a method for adjusting the pressure in the supply oil passage when the attachment is replaced will be described with reference to FIG. 3 taking the case where the first attachment A1 is replaced as an example. Here, a case where two breakers having different specifications (one as a first breaker and the other as a second breaker) are replaced and mounted as the first attachment A1 will be described. It is assumed that the first breaker is configured to be used at the pressure set value α, and the second breaker is configured to be used at the pressure set value β. First, when the first breaker is mounted, the operator operates the attachment hydraulic pressure setting switch S1 to specify the set value of the pressure in the section oil passage 31 as the set value α. Based on this designation, the control unit CU adjusts the current value input to the proportional solenoid of the electromagnetic proportional relief valve 35, so that when the first breaker is used, pressure regulation control according to the set value α is performed. This is performed by an electromagnetic proportional relief valve 35.

  When the first breaker is removed and the second breaker is attached, the operator operates the attachment oil pressure setting switch S1 to designate the set value of the pressure in the section oil passage 31 as the set value β. Based on this designation, the control unit CU adjusts the current value input to the proportional solenoid of the electromagnetic proportional relief valve 35, so that when the second breaker is used, pressure regulation control according to the set value β is performed. This is performed by an electromagnetic proportional relief valve 35.

  Thus, when replacing attachments with different specifications of the pressure setting value, the operator simply operates the attachment oil pressure setting switch S1 to specify the pressure setting value in the section oil passage 31. The pressure regulation control according to is performed. For this reason, it is possible to easily and accurately adjust the pressure in the supply oil passage when the attachment is replaced.

  Note that the control unit CU can store the setting value once specified, and when the attachment that has been once mounted is used again, it is set and stored at the time of previous use. It is also possible to perform pressure regulation control in the supply oil passage by reading the set value and setting it again. In this case, the control unit CU displays the stored setting value (or a plurality of setting values) on a display panel or the like, and the operator selects and specifies an appropriate setting value from the displayed setting values. It may be.

  Moreover, although the adjustment method of the pressure in the supply oil path when the 1st attachment A1 was replaced | exchanged here was demonstrated, the pressure in the supply oil path when the 2nd attachment A2 and the 3rd attachment A3 were replaced | exchanged It is possible to perform the adjustment in the same manner. Furthermore, here, the case where the same type of attachment with different specifications is replaced has been described as an example, but the pressure adjustment work (setting value adjustment) can be performed in the same manner when the attachment with a different type is replaced. Is possible.

Moreover, although the case where this invention was applied to a power shovel was demonstrated in the above-mentioned embodiment, this invention can also be applied to other working machines, such as a crawler loader other than a power shovel.

1 Excavator 31, 51-53 Section oil passage 35, 59 Electromagnetic proportional relief valve 38, 55 Electromagnetic control valve A1 1st attachment A2 2nd attachment A3 3rd attachment C1 to C3 Hydraulic takeout part S1 Attachment oil pressure setting switch V11 1st Attachment control valve V12 2nd and 3rd attachment control valve CU Control device P1 Main hydraulic pump P2 Auxiliary hydraulic pump E Engine

Claims (2)

A work machine configured to selectively attach and detach a plurality of types of attachments that operate under hydraulic pressure,
A hydraulic outlet provided to supply hydraulic pressure to the attachment;
A hydraulic source supplying hydraulic pressure;
A supply oil passage for supplying oil pressure from the hydraulic pressure source to the hydraulic pressure take-out part;
A supply control valve provided in the supply oil path for controlling supply of oil pressure to the attachment;
An electromagnetic pressure control valve for controlling the pressure in the extraction side section oil passage from the supply control valve to the hydraulic pressure take-out section in the supply oil passage;
A set value designating unit for designating a set value of the pressure in the extraction side section oil passage according to the type of the attachment;
A work machine comprising pressure control valve control means for electrically controlling the electromagnetic pressure control valve so that the pressure in the extraction side section oil passage becomes a specified set value. A branch return oil passage for branching from the extraction side section oil passage to the oil tank, and returning the return oil from the attachment to the oil tank without going through the supply control valve;
An opening and closing solenoid valve that is provided in the branch return oil passage and operates to open and close the branch return oil passage;
The work machine according to claim 1, further comprising: an open / close electromagnetic valve control unit that controls an open / close operation of the open / close electromagnetic valve.

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