JP2013147886A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction machine for enabling a change in the operation mode of an attachment depending on an end attachment mounted thereon.SOLUTION: The construction machine relating to the embodiment of this invention includes an end attachment flow control part 300 for controlling the flow of operating oil into a special hydraulic cylinder 9b of an end attachment 6, an attachment operation restricting part 301 for selectively restricting the operation of the attachment, and a controller 30 for controlling the end attachment flow control part 300 and the attachment operation restricting part 301. The controller 30 controls the end attachment flow control part 300 so that the operating oil flows into the special hydraulic cylinder 9b at a higher flow rate when a pre-crusher is mounted thereon than when a fork grapple is mounted thereon, and controls the attachment operation restricting part 301 so that the operation of the attachment is limited.

Description

  The present invention relates to a construction machine capable of changing a plurality of end attachments.

  Conventionally, it is a construction machine with an attachment including a first boom, a second boom, and an arm, and the movement of the first boom or the second boom is regulated according to the working state (separate work at high places or low places) There is known a construction machine including a working range restriction mechanism (see, for example, Patent Documents 1 and 2).

JP 2007-209917 A JP 2009-121095 A

  However, all of the techniques described in Patent Documents 1 and 2 only regulate the movement of the first boom or the second boom when a single crusher is mounted as an end attachment, depending on the working state. It is not envisaged that a single crusher can be replaced with another end attachment.

  In view of the above-described points, an object of the present invention is to provide a construction machine that can change the operation mode of an attachment in accordance with the attached end attachment.

  In order to achieve the above-described object, a construction machine according to an embodiment of the present invention is a construction machine including an attachment capable of changing a plurality of end attachments including a hydraulically driven end attachment having a dedicated hydraulic actuator. An end attachment flow rate control unit that controls the flow rate of hydraulic fluid flowing into the hydraulic actuator, an attachment operation regulation unit that selectively regulates movement of the attachment, the end attachment flow rate control unit, and the attachment operation regulation unit. And when the first end attachment of the plurality of end attachments is mounted, the controller is mounted with the second end attachment of the plurality of end attachments. Compared to the oil Controls said end attachment flow controller so that the flow rate of the hydraulic oil flowing into the actuator is increased, and, and controls the attachment operation restricting portion such that movement of the attachment is limited.

  By the means described above, the present invention can provide a construction machine that can change the operation mode of the attachment in accordance with the attached end attachment.

It is a side view which shows the construction machine which concerns on the Example of this invention. It is the schematic which shows the structural example of the hydraulic circuit mounted in the construction machine of FIG. FIG. 2 is a schematic diagram (part 1) illustrating a configuration example of a control system mounted on the construction machine of FIG. 1. FIG. 3 is a schematic diagram (part 2) illustrating a configuration example of a control system mounted on the construction machine of FIG. 1. It is a flowchart which shows the flow of an operation | movement mode switching process. It is FIG. (1) explaining the work range of the attachment at the time of using the construction machine of FIG. 1 for house dismantling. It is FIG. (2) explaining the work range of the attachment at the time of using the construction machine of FIG. 1 for a house dismantling.

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

  FIG. 1 is a side view showing a construction machine according to an embodiment of the present invention. In this embodiment, the construction machine is, for example, an ultra-small turning two-piece boom machine, and an upper turning body 3 is turnably mounted on a crawler type lower traveling body 1 via a turning mechanism 2.

  The upper swing body 3 includes a first boom 4a, a second boom 4b, an arm 5, an end attachment (fork grapple) 6, and a first boom cylinder 7a and a second boom cylinder for driving each of them in the front center portion. 7b, an arm cylinder 8, an end attachment opening / closing cylinder 9a, and an end attachment driving cylinder 9b are mounted. In addition, the upper swing body 3 has a cabin 10 for an operator to get on, and an engine (not shown) as a drive source on the rear. The end attachment opening / closing cylinder 9 a is a hydraulic cylinder for opening and closing (turning) the end attachment 6 with respect to the arm 5. The end attachment driving cylinder 9b is a dedicated hydraulic actuator attached to the end attachment 6 in order to drive the end attachment 6 itself (for example, to open and close the fork grapple 6).

  FIG. 2 is a schematic diagram showing a configuration example of a hydraulic circuit mounted on the construction machine of FIG. In the present embodiment, the hydraulic circuit circulates the hydraulic oil from the two main pumps 12L and 12R driven by the engine to the oil tank through the center bypass oil passages 40L and 40R.

  The main pumps 12L and 12R are devices for supplying hydraulic oil to the control valves 150 and 161 and the flow rate control valves 151 to 160 via high-pressure oil passages. For example, the main pumps 12L and 12R are swash plate type variable displacement hydraulic pumps. is there. In the present embodiment, negative control control is adopted as the pump control method of the main pumps 12L and 12R, but other control methods may be adopted.

  The center bypass oil passage 40L is a high-pressure oil passage that communicates the flow control valves 151, 153, 155, 157, and 159, and the center bypass oil passage 40R includes the control valve 150, the flow control valves 152, 154, 156, and 159. , 160 and a high-pressure oil passage communicating with the control valve 161.

  The control valve 150 is a traveling straight valve, and is a spool valve that operates when left and right traveling hydraulic motors 1L, 1R that drive the lower traveling body 1 and other hydraulic actuators are operated simultaneously. Specifically, the control valve 150 switches the flow of the hydraulic oil so as to circulate the hydraulic oil from only the main pump 12L to each of the flow control valve 151 and the flow control valve 152 in order to improve the straightness of the lower traveling body 1. be able to.

  The flow rate control valve 151 is a spool valve that switches the flow of hydraulic oil in order to circulate the hydraulic oil discharged from the main pump 12L by the left-side traveling hydraulic motor 1L, and the flow rate control valve 152 is discharged from the main pump 12L or 12R. This is a spool valve that switches the flow of hydraulic oil in order to circulate the hydraulic oil to be circulated by the right traveling hydraulic motor 1R.

  The flow rate control valve 153 is a spool valve that switches the flow of hydraulic oil in order to circulate the hydraulic oil discharged from the main pumps 12L and 12R in the end attachment driving cylinder 9b.

  The flow control valve 154 is a spool valve for supplying the hydraulic oil discharged from the main pump 12R to the end attachment opening / closing cylinder 9a and discharging the hydraulic oil in the end attachment opening / closing cylinder 9a to the oil tank.

  The flow rate control valve 155 is a spool valve that switches the flow of hydraulic oil so that the hydraulic oil discharged from the main pumps 12L and 12R is circulated by the turning hydraulic motor 2A.

  The flow control valves 156 and 157 supply the hydraulic oil discharged from the main pumps 12L and 12R to the first boom cylinder 7a, and discharge the hydraulic oil in the first boom cylinder 7a to the oil tank. It is a spool valve that switches the flow. The flow control valve 156 is a spool valve (hereinafter referred to as a “first boom flow control valve”) that always operates when a boom operation lever (not shown) is operated. Further, the flow control valve 157 is a spool valve that operates only when the boom operation lever is operated in the raising (opening) direction beyond a predetermined lever operation amount (hereinafter referred to as “second boom flow control valve”). It is.

  The flow rate control valves 158 and 159 supply the working oil discharged from the main pumps 12L and 12R to the arm cylinder 8, and spools for switching the flow of the working oil in order to discharge the working oil in the arm cylinder 8 to the oil tank. It is a valve. The flow control valve 159 is a valve that is always operated when an arm operation lever (not shown) is operated (hereinafter referred to as “first arm flow control valve”). The flow control valve 158 is a valve that operates only when the arm operation lever is operated at a predetermined lever operation amount or more (hereinafter referred to as “second arm flow control valve”).

  The flow control valve 160 is a spool valve for supplying the hydraulic oil discharged from the main pump 12R to the second boom cylinder 7b and discharging the hydraulic oil in the second boom cylinder 7b to the oil tank.

  The control valve 161 is a valve for switching whether or not to allow the hydraulic oil discharged from the main pump 12R to reach a negative control throttle (not shown).

  The first solenoid valve 21 is a valve that switches whether hydraulic oil discharged from the main pump 12R is supplied to the end attachment driving cylinder 9b via the flow rate control valve 153 in accordance with a control signal from the controller 30 described later. is there. When the first solenoid valve 21 is in the open state, the hydraulic oil discharged from the main pump 12R can join the hydraulic oil discharged from the main pump 12L and flow into the end attachment driving cylinder 9b via the flow control valve 153. .

  Next, the movement of the attachment included in the construction machine of FIG. 1 will be described with reference to FIGS. 3 and 4 are schematic diagrams illustrating a configuration example of a control system mounted on the construction machine of FIG. 3 and 4, the high-pressure oil passage, the pilot oil passage, and the electrical wiring are respectively indicated by a thick solid line, a broken line, and a one-dot chain line. 3 and 4, the construction machine is in a state suitable for work in a low place, that is, in a state where the first boom 4 a is tilted over a predetermined angle.

  3 shows a case where a fork grapple as the end attachment 6 is attached to the tip of the arm 5, and FIG. 4 shows a case where a large crusher as the end attachment 6 is attached to the tip of the arm 5.

  The second boom operation lever 16A is an operation device for operating the second boom 4b, and uses the hydraulic oil discharged from the control pump 14 to apply a pilot pressure corresponding to the lever operation amount in the flow control valve 160. It is introduced to either the left or right pilot port. The left pilot port 160a is a port for lowering the second boom 4b, and the right pilot port 160b is a port for raising the second boom 4b.

  The end attachment operating lever 16B is an operating device for operating the end attachment 6 using the end attachment driving cylinder 9b, and is a pilot corresponding to the lever operating amount using the hydraulic oil discharged by the control pump 14. The pressure is introduced into either the left or right pilot port in the flow control valve 153. The left pilot port 153 a is a port for closing the fork grapple 6, and the right pilot port 153 b is a port for opening the fork grapple 6.

  The attitude sensor 17 is a sensor for detecting the attitude of the attachment, and outputs a detection signal including a detection value to the controller 30 described later. The posture sensor 17 is, for example, a sensor that detects the degree of rise (opening) of the second boom 4b as the posture of the attachment, and specifically detects the angle between the first boom 4a and the second boom 4b. It is an angle sensor. In this case, the posture sensor 17 may be a displacement sensor or a stroke sensor that detects the expansion / contraction state of the second boom cylinder 7b. Alternatively, the attitude sensor 17 may be a proximity sensor for detecting whether or not the angle between the first boom 4a and the second boom 4b is a predetermined value or more. In this case, the proximity sensor is, for example, a magnetic proximity sensor, and detects a state in which a part of the first boom 4a exists nearby as long as the angle is less than a predetermined value. It arrange | positions on the 2nd boom 4b so that the state may not be detected.

  The changeover switch 18 is a component for notifying which controller 30 described later which end attachment 6 is attached to the attachment. In the present embodiment, the changeover switch 18 enables the operator to select “crusher mode” and “fork mode”. The “crusher mode” is an operation for outputting to the controller 30 a control signal indicating that a relatively heavy end attachment such as a large crusher, a small crusher, or a steel cutter is attached to the tip of the arm 5. Mode. The “fork mode” is an operation mode in which a control signal indicating that an end attachment having a relatively small weight such as a bucket, a breaker, or a fork grapple is attached to the tip of the arm 5 is output to the controller 30. The changeover switch 18 allows the operator to select a “bucket mode” in which a control signal indicating that a bucket that does not have the end attachment driving cylinder 9 b is attached to the tip of the arm 5 is output to the controller 30. Alternatively, another operation mode may be selected by the operator.

  The second solenoid valve 22 is a valve that switches whether to transmit the pilot pressure generated by the operation lever to the flow control valve. In the present embodiment, the second solenoid valve 22 generates a pilot pressure for raising (opening) the second boom 4b generated by the second boom operation lever 16A in response to a control signal from the controller 30. Whether to transmit to 160 pilot ports 160b is switched. Specifically, when the second solenoid valve 22 is in an open state, the hydraulic oil discharged from the pilot pump 14 flows into the pilot port 160 b through the second solenoid valve 22. In this case, the pilot pressure for raising (opening) the second boom 4 b is transmitted to the pilot port 160 b of the flow control valve 160.

  The controller 30 is a control device for controlling the hydraulic circuit, and includes, for example, a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like.

  In addition, the controller 30 reads each program corresponding to each of the end attachment flow rate control unit 300 and the attachment operation regulation unit 301 from a non-volatile storage medium such as a ROM and develops the program on a volatile storage medium such as a RAM, thereby corresponding to each. CPU is caused to execute the process. The end attachment flow rate control unit 300 is a functional element that controls the flow rate of the hydraulic fluid flowing into the end attachment drive cylinder 9b. Further, the attachment operation restriction unit 301 is a functional element that selectively restricts the movement of the attachment.

  Specifically, the controller 30 receives the detection signal output from the attitude sensor 17 and the control signal output from the changeover switch 18, and each of the end attachment flow control unit 300 and the attachment operation restriction unit 301 based on these signals. Execute the process. Thereafter, the controller 30 appropriately outputs control signals corresponding to the processing results of the end attachment flow control unit 300 and the attachment operation restriction unit 301 to the first solenoid valve 21 and the second solenoid valve 22, respectively.

  More specifically, when the end attachment flow rate control unit 300 of the controller 30 receives a control signal indicating the “fork mode” from the changeover switch 18, the control signal including the close command to the first solenoid valve 21 (hereinafter, referred to as a “fork mode”). "Close signal") is output. As shown in FIG. 3, the first solenoid valve 21 that has received the close signal prohibits the hydraulic oil discharged from the main pump 12R from flowing into the end attachment driving cylinder 9b. In this case, when the end attachment operating lever 16B is operated in the opening direction, only the hydraulic oil discharged from the main pump 12L flows into the end attachment driving cylinder 9b through the flow control valve 153 and the fork grapple 6 opens. Driven by. The same applies to the closing direction.

  When the attachment operation restricting unit 301 receives the control signal indicating the “fork mode” from the changeover switch 18, the attachment operation restricting unit 301 includes a control signal (hereinafter referred to as an open command) for the second solenoid valve 22 regardless of the detection signal from the attitude sensor 17. , "Open signal"). As shown in FIG. 3, the second solenoid valve 22 that has received the open signal permits the hydraulic oil discharged from the pilot pump 14 to flow into the pilot port 160 b of the flow control valve 160. In this case, when the second boom operation lever 16A is operated in the raising (opening) direction, the hydraulic oil discharged from the main pump 12R flows into the bottom side oil chamber of the second boom cylinder 7b. In this way, the second boom 4b is driven in the raising (opening) direction without any restriction.

  Note that the attachment operation restricting unit 301 also outputs an open signal to the second solenoid valve 22 regardless of the detection signal from the attitude sensor 17 even when the control signal indicating the “bucket mode” is received from the changeover switch 18. Output. This is because the weight of the bucket is relatively small, so that even if the work radius of the attachment increases, the construction machine does not fall down, and there is no need to regulate the movement of the attachment.

  On the other hand, when receiving the control signal indicating the “crusher mode” from the changeover switch 18, the end attachment flow rate control unit 300 outputs an open signal to the first solenoid valve 21, and as shown in FIG. The hydraulic oil discharged from 12R is allowed to flow into the end attachment drive cylinder 9b. In this case, when the end attachment operation lever 16B is operated in the opening direction, the hydraulic oil discharged from the main pump 12L and the hydraulic oil discharged from the main pump 12R merge and flow into the flow control valve 153. The joined hydraulic oil flows into the end attachment driving cylinder 9b through the flow control valve 153 and drives the large crusher 6 in the opening direction. The same applies to the closing direction.

  The attachment movement restricting unit 301 receives a control signal indicating the “crusher mode” from the changeover switch 18, and an angle between the first boom 4 a and the second boom 4 b based on the detection signal from the attitude sensor 17. Is determined to be equal to or greater than a predetermined value, a close signal is output to the second solenoid valve 22. As shown in FIG. 4, the second solenoid valve 22 that has received the close signal inhibits the hydraulic oil discharged from the pilot pump 14 from flowing into the pilot port 160 b of the flow control valve 160. In this case, even if the second boom operation lever 16A is operated in the raising (opening) direction, the hydraulic oil discharged from the pilot pump 14 does not flow into the pilot port 160b. As a result, the flow control valve 160 is maintained in the neutral position, and the hydraulic oil discharged from the main pump 12R is discharged to the hydraulic oil tank without flowing into the bottom side oil chamber of the second boom cylinder 7b. In this way, the raising (opening) operation of the second boom 4b is prohibited so that the angle between the first boom 4a and the second boom 4b becomes a predetermined value or more.

  When the changeover switch 18 is configured to be able to select the “bucket mode”, the controller 30 receives the control signal indicating the “bucket mode” from the changeover switch 18 and then the first solenoid valve 21. The end attachment flow rate control unit 300 is controlled so as to output a close signal, and the attachment operation restricting unit 301 is controlled so as to output an open signal to the second solenoid valve 22. That is, the controller 30 controls the end attachment flow rate control unit 300 in the same manner as when receiving the control signal indicating the “fork mode”, and controls the attachment operation restricting unit 301 so that the movement of the attachment is not restricted. Also good. This is because the bucket 6 does not have the end attachment driving cylinder 9b and the end attachment operating lever 16B is not operated.

  Next, a process in which the controller 30 switches the operation mode of the end attachment 6 (hereinafter referred to as “operation mode switching process”) will be described with reference to FIG. FIG. 5 is a flowchart showing the flow of the operation mode switching process, and the controller 30 repeatedly executes this operation mode switching process at a predetermined cycle.

  First, the controller 30 determines whether the construction machine is in the “crusher mode” or the “fork mode” based on the control signal output from the changeover switch 18 (step S1).

  When the controller 30 determines that the mode is the “fork mode” (“fork mode” in step S1), the end attachment flow rate controller 300 of the controller 30 outputs a close signal to the first solenoid valve 21 to output the solenoid valve. 21 is closed (step S2). This is to shut off the conduit between the main pump 12R and the flow control valve 153. In this way, when the end attachment operation lever 16B is operated, the end attachment flow control unit 300 supplies only the hydraulic oil discharged from the main pump 12L to the end attachment driving cylinder 9b.

  Moreover, the attachment operation | movement control part 301 of the controller 30 outputs an open signal with respect to the 2nd solenoid valve 22, and opens the solenoid valve 22 (step S3). This is because the pipe line between the second boom operation lever 16A and the pilot port 160b of the flow control valve 160 is communicated so that the hydraulic oil discharged from the pilot pump 14 can flow into the pilot port 160b. In this way, the attachment operation restricting unit 301 raises (opens) the second boom 4b without any restriction even when the second boom operation lever 16A is operated in the up (open) direction. To be driven in the direction.

  On the other hand, when the controller 30 determines that it is in the “crusher mode” (“crusher mode” in step S1), the end attachment flow control unit 300 outputs an open signal to the first solenoid valve 21 to output a solenoid. The valve 21 is opened (step S4). This is because the pipe line between the main pump 12R and the flow control valve 153 is communicated. Thereby, when the end attachment operation lever 16B is operated, the end attachment flow control unit 300 supplies the hydraulic oil discharged from the main pump 12L and the main pump 12R to the end attachment driving cylinder 9b. To. Hereinafter, supplying the hydraulic oil discharged from the main pump 12L and the hydraulic oil discharged from the main pump 12R to the end attachment driving cylinder 9b at the same time is referred to as “second speed merging”.

  Thereafter, the controller 30 determines whether the angle α between the first boom 4a and the second boom 4b is equal to or greater than a predetermined value TH based on the detection signal of the attitude sensor 17 (step S5).

  When the controller 30 determines that the angle α is equal to or greater than the predetermined value TH (YES in step S5), the attachment operation restriction unit 301 outputs a close signal to the second solenoid valve 22 to close the solenoid valve 22 ( Step S6). This is because the pipeline between the second boom operation lever 16A and the pilot port 160b of the flow control valve 160 is blocked so that the hydraulic oil discharged from the pilot pump 14 cannot flow into the pilot port 160b. In this way, the attachment operation restricting section 301 is prohibited from moving the second boom 4b in the raising (opening) direction even when the second boom operation lever 16A is operated in the raising (opening) direction. So that This is because the angle α is already equal to or greater than the predetermined value TH, and therefore the construction machine may fall over if the second boom 4b is further raised (opened).

  On the other hand, when the controller 30 determines that the angle α is less than the predetermined value TH (NO in step S5), the attachment operation restricting unit 301 outputs an open signal to the second solenoid valve 22 as in step S3. Then, the solenoid valve 22 is opened (step S7). This is because the pipe line between the second boom operation lever 16A and the pilot port 160b of the flow control valve 160 is communicated so that the hydraulic oil discharged from the pilot pump 14 can flow into the pilot port 160b. Thereby, the attachment operation restricting unit 301 is driven in the raising (opening) direction without any restriction when the second boom operation lever 16A is operated in the raising (opening) direction. So that This is because the angle α is still less than the predetermined value TH, and even if the second boom 4b is further raised (opened), there is no possibility that the construction machine will fall.

  As described above, the controller 30 switches the operation mode of the end attachment 6 in accordance with the control signal output from the changeover switch 18. As a result, when the large crusher 6 having a relatively large weight is attached, the controller 30 restricts the movement of the attachment (working range), thereby excessively increasing the work radius of the attachment. Can be prevented from becoming unstable. That is, the operator can safely work even when the large crusher 6 is mounted. Further, the controller 30 does not restrict the movement of the attachment when the fork grapple 6 having a relatively small weight is attached. As a result, the operator can perform a wide range of work using the fork grapple 6.

  Further, when the large crusher 6 having a relatively large weight is mounted, the controller 30 supplies a large flow rate of hydraulic oil to the end attachment driving cylinder 9b by the second speed merging. As a result, the controller 30 can cause the large crusher 6 driven by the end attachment driving cylinder 9b having a relatively large cylinder volume to move at an optimum operating speed. Further, when the fork grapple 6 having a relatively small weight is attached, the controller 30 supplies only the hydraulic oil discharged from the main pump 12L to the end attachment driving cylinder 9b. As a result, the controller 30 can cause the fork grapple 6 driven by the end attachment driving cylinder 9b having a relatively small cylinder volume to move at an optimum operating speed.

  Next, the work range of the attachment when the construction machine according to the embodiment of the present invention is used for dismantling a house will be described with reference to FIGS. FIG. 6 shows a construction machine used for dismantling the roof H built on the fabric foundation F1. Specifically, FIG. 6 (A) shows a construction machine equipped with a fork grapple 6 used for dismantling the roof H, and FIG. 6 (B) is used to dig up the fabric foundation F1. The construction machine with which the bucket 6 was mounted | worn is shown. FIG. 7 shows a construction machine used to dismantle the roof H built on the solid foundation F2. Specifically, FIG. 7 (A) shows a construction machine equipped with a fork grapple 6 used for dismantling the roof H, and FIG. 7 (B) is used for crushing the solid foundation F2. The construction machine with which the large crusher 6 mounted is mounted | worn is shown.

  As shown in FIGS. 6A and 7A, when disassembling the roof H, the fork grapple 6 having a relatively small weight is attached to the tip of the arm 5. In this case, as shown in FIG. 3, the operator uses the changeover switch 18 to select “fork mode”. The controller 30 that has received the control signal from the changeover switch 18 controls the end attachment flow rate controller 300 so that only the hydraulic oil discharged from the main pump 12L can flow into the end attachment drive cylinder 9b. As a result, the fork grapple 6 can be operated at an appropriate operating speed. Further, the controller 30 controls the attachment operation restricting unit 301 so that the hydraulic oil discharged from the pilot pump 14 can flow into the pilot port 160b of the flow control valve 160. As a result, the work range of the attachment, that is, the reachable range of the fork grapple 6 is the range indicated by the region R1. In this way, when the fork grapple 6 having a relatively small weight is attached, the construction machine allows the fork grapple 6 to reach as wide a range as possible without restricting the movement of the attachment so as to improve work efficiency. To. This is because the work machine has no fear of falling.

  Further, as shown in FIG. 6B, when digging up the fabric foundation F <b> 1, the bucket 6 having a relatively small weight is attached to the tip of the arm 5. In this case, the operator uses the changeover switch 18 to select “fork mode”. Alternatively, when the changeover switch 18 is configured to be able to select “bucket mode”, “bucket mode” is selected. The controller 30 that has received the control signal from the changeover switch 18 controls the attachment operation restricting unit 301 so that the hydraulic oil discharged from the pilot pump 14 can flow into the pilot port 160 b of the flow control valve 160. As a result, the work range of the attachment, that is, the range that the bucket 6 can reach is the range indicated by the region R2. As described above, when the construction machine digs up the fabric foundation F1 using the bucket 6 having a relatively small weight, the bucket 6 can reach the widest possible range without restricting the movement of the attachment. Try to increase. This is because the work machine has no fear of falling.

  Note that FIG. 6B shows the state of the second boom 4b when the second boom cylinder 7b is most contracted by a solid line in order to show that the movement of the second boom 4b is not restricted. A state of the second boom 4b when the boom cylinder 7b is most extended is indicated by a broken line.

  Further, as shown in FIG. 7B, when crushing the solid foundation F <b> 2, a relatively large weight crusher 6 is attached to the tip of the arm 5. In this case, the operator uses the changeover switch 18 to select “crusher mode”. The controller 30 that has received the control signal from the changeover switch 18 controls the end attachment flow rate so that the hydraulic oil discharged from the main pump 12L and the hydraulic oil discharged from the main pump 12R can flow into the end attachment driving cylinder 9b. The unit 300 is controlled. As a result, the large crusher 6 can be operated at an appropriate operation speed. Further, the controller 30 controls the attachment operation restricting unit 301 so that the hydraulic oil discharged from the pilot pump 14 cannot flow into the pilot port 160 b of the flow control valve 160. As a result, the work range of the attachment, that is, the range that can be reached by the large crusher 6 is the range indicated by the region R3 that is narrower than the range that can be reached by the bucket 6 in FIG. Become. Thus, when the construction machine crushes the solid foundation F2 by using the relatively large weight crusher 6, the movement of the attachment is restricted, and the working radius of the attachment increases excessively. So that it does n’t fall.

  FIG. 7B shows the state of the second boom 4b when the second boom cylinder 7b is contracted most in a broken line in order to show that the movement of the second boom 4b is restricted. The state of the second boom 4b when the extension of the boom cylinder 7b is restricted is indicated by a solid line.

  As described above, the construction machine according to the embodiment of the present invention has a function of restricting the movement of the attachment and a function of increasing the flow rate of the hydraulic oil flowing into the end attachment driving cylinder 9b. Therefore, even when a relatively heavy end attachment such as a large crusher is mounted, the stability of the construction machine and the optimum operation speed of the end attachment can be ensured. As a result, it is possible to use a large crusher even in a small excavator such as an ultra-small turning two-piece boom machine equipped with a relatively small end attachment such as a fork grapple as standard, and a solid foundation using such a small excavator. It becomes possible to use a large crusher for the dismantling.

  In many cases, the site of the house dismantling is narrow, and it is often required to dismantle the roof with a single small excavator and crush and dig up the foundation. Therefore, it is useful to be able to replace the fork grapple of the small excavator with the large crusher while ensuring the stability of the small excavator and the optimum operating speed of the end attachment.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the controller 30 determines which end attachment is mounted based on a control signal output from the changeover switch 18 that is manually operated by the operator. However, the present invention is not limited to this. For example, in addition to the changeover switch 18 or instead of the changeover switch 18, an end attachment recognition unit that automatically recognizes which end attachment is attached may be provided. The controller 30 determines which end attachment is attached based on the recognition result of the end attachment recognition unit. In addition, as an end attachment recognition part, arbitrary appropriate apparatuses, such as an apparatus which reads the intrinsic | native magnetic pattern which the magnetic body embedded in each end attachment emits, for example can be employ | adopted.

  In the above-described embodiment, the attachment operation restricting unit 301 selectively restricts the movement of the second boom 4 b using the second solenoid valve 22. However, the present invention is not limited to this. For example, the attachment movement restricting unit 301 may selectively restrict at least one of the first boom 4a, the arm 5, and the turning mechanism 2 in addition or alternatively.

  DESCRIPTION OF SYMBOLS 1 ... Lower traveling body 1L, 1R ... Traveling hydraulic motor 2 ... Turning mechanism 2A ... Turning hydraulic motor 3 ... Upper turning body 4a ... First boom 4b ... First Two boom 5 ... Arm 6 ... End attachment (fork grapple, large crusher, bucket) 7a ... First boom cylinder 7b ... Second boom cylinder 8 ... Arm cylinder 9a ... End attachment opening / closing cylinder 9b ... End attachment driving cylinder 10 ... Cabin 12L, 12R ... Main pump 14 ... Pilot pump 16A ... Second boom operation lever 16B ... End attachment operation lever 18 ... changeover switch 21 ... first solenoid valve 22 ... second solenoid valve 30 Controller 40L, 40R Center bypass oil passage 150, 161 ... Control valve 151-160 ... Flow control valve 153a, 153b, 160a, 160b ... Pilot port 300 ... End attachment flow control unit 301 ... Attachment operation restricting section

Claims (6)

A construction machine having an attachment capable of changing a plurality of end attachments including a hydraulically driven end attachment having a dedicated hydraulic actuator,
An end attachment flow rate control unit for controlling the flow rate of hydraulic oil flowing into the hydraulic actuator;
An attachment operation restricting unit that selectively restricts movement of the attachment;
A controller that controls the end attachment flow rate control unit and the attachment operation restriction unit;
The controller flows into the hydraulic actuator when the first end attachment of the plurality of end attachments is attached compared to when the second end attachment of the plurality of end attachments is attached. Controlling the end attachment flow rate control unit so that the flow rate of hydraulic oil increases, and controlling the attachment operation restricting unit so that movement of the attachment is limited;
Construction machinery characterized by that. The weight of the first end attachment is greater than the weight of the second end attachment;
The construction machine according to claim 1. The attachment includes a first boom, a second boom, and an arm,
The attachment operation restricting portion restricts the opening of the second boom;
The construction machine according to claim 1 or 2, characterized in that. Have two hydraulic pumps,
The end attachment flow rate control unit increases the flow rate of hydraulic oil flowing into the hydraulic actuator by switching the supply of hydraulic oil from one hydraulic pump to the supply of hydraulic oil from two hydraulic pumps.
The construction machine according to any one of claims 1 to 3, wherein A switch for notifying the controller that the first end attachment is attached or the second end attachment is attached;
The construction machine according to any one of claims 1 to 4, wherein An end attachment recognizing unit that recognizes that the first end attachment is attached or the second end attachment is attached and notifies the controller;
The construction machine according to any one of claims 1 to 5, wherein

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