Construction machinery

Abstract

The present invention provides a hydraulic excavator that can prevent collision of the front work device with the vehicle body due to erroneous operation of the operating lever when operating the release switch device for disabling interference prevention control. [Solution] The offset hydraulic excavator is equipped with a release switch 53 for performing an operation to release the interference prevention control. When the release operation is performed by the release switch 53 while the interference prevention control is running, if the shut-off lever 43 is in an inoperable state, the control unit 32 releases the interference prevention control. When the release operation is performed by the release switch 53 while the interference prevention control is running, if the shut-off lever 43 is in an operational state, the interference prevention control continues.

Description

TECHNICAL FIELD

[0001] The present invention relates to a construction machine that performs area limit control for a front working device.

BACKGROUND ART

[0002] For example, a hydraulic excavator equipped with an offset-type front working device (hereinafter appropriately referred to as "offset-type hydraulic excavator") has the advantage that offset operation of the front working device facilitates trenching work along roads and excavation, swinging, and loading work in narrow spaces such as roads sandwiched between residences. However, in the offset-type hydraulic excavator, since the front working device is subjected to offset operation, the front working device (particularly the bucket) may collide (interfere) with the operator's cab depending on the posture of the front working device. In order to prevent such interference between the front working device and the cab, the offset-type hydraulic excavator is generally provided with an interference prevention device that performs interference prevention control.

[0003] In the control of this interference prevention device, normally, a deceleration region and a stop region are set around the operator's cab from the outside toward the inside. For example, when the bucket enters the deceleration region due to arm crowding operation and / or boom raising operation, the command pilot pressure applied to the flow control valve is reduced by an electromagnetic proportional pressure reducing valve provided in the pilot line of the flow control valve related to the arm crowding operation and / or boom raising operation, so as to decelerate the arm crowding operation and / or boom raising operation. When the bucket enters the stop region, the electromagnetic proportional pressure reducing valve is fully closed to automatically stop the arm crowding operation and / or boom raising operation.

[0004] For example, Patent Document 1 describes a vehicle body having a driver's cab, an offset-type front work device mounted on the vehicle body so as to be rotatable in the vertical direction, an operating lever for instructing the operation of a plurality of front members constituting the front work device, a plurality of hydraulic actuators for driving each of the plurality of front members, a hydraulic pump for supplying pressurized oil to the plurality of hydraulic actuators, an engine for driving the hydraulic pump, and setting stop areas and prohibited areas sequentially around the driver's cab from the outside to the inside, and stopping the operation of the front work device by stopping the operation of the front member when the front work device enters the stop area by operating at least one of the plurality of front members, and stopping the operation of the front work device by stopping the operation of the front member, and stopping the operation of the machine body and the front work device when the front work device enters the prohibited area beyond the stop area, and stopping all operations of the machine body and the front work device and the refrigerant The present invention discloses a construction machine equipped with an interference prevention device that performs interference prevention control to disable all operations of the work equipment, the construction machine comprising a momentary release switch device having a first position and a second position, which returns to the first position when pressed from the first position to the second position and the pressing operation is released, and an operating device for switching the operating mode of the release switch device between a first mode and a second mode, wherein when the operating mode of the release switch device is in the first mode, the interference prevention control is released only while the release switch device is pressed down to the second position, and when the operating mode of the release switch device is in the second mode and the release switch device is pressed to the second position, the interference prevention control is released and the release state of the interference prevention control is maintained even after the pressing operation is released and the release switch device returns to the first position. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-229837 [Overview of the project] [Problems that the invention aims to solve]

[0006] The state in which interference prevention control is activated is when the front work device is in an area close to the vehicle body (stop area or prohibited area; hereinafter referred to as "stop area, etc." as appropriate), and its operation is stopped because there is a risk of collision with the vehicle body if it is moved any further. Therefore, if interference prevention control is to be released in this state, it is assumed that the front work device is located in the aforementioned proximity area. Consequently, if the operating lever is misoperated when releasing interference prevention control, there is a high probability that the front work device will collide with the vehicle body.

[0007] In the conventional technology described above, when the interference prevention control is deactivated by operating a release switch device, there is a possibility that the operator's body or clothing may unintentionally touch the operating lever when the operator changes their posture to operate the release switch device. In that case, the operating lever may be misoperated, causing the front work device to move unintentionally, and there is a risk that the front work device will collide with the vehicle body.

[0008] The present invention has been made in view of the above circumstances, and its purpose is to provide a construction machine that can prevent the front work device from colliding with the vehicle body due to erroneous operation of the operating lever when operating the release switch device for releasing interference prevention control. [Means for solving the problem]

[0009] To achieve the above objective, the present invention provides a construction machine comprising: a vehicle body; a front work device provided on the vehicle body so as to be movable up and down and including a plurality of front members; a driver's cab provided on the vehicle body and having a driver's seat inside; an operating device located in the driver's cab for operating the front work device; a shut-off lever located in the driver's cab that can switch between an operation-disabled state that disables the operation of the operating device and an operation-enabled state that enables the operation of the operating device; a controller that performs interference prevention control to stop the operation of the front work device when the front work device enters a predetermined area set around the driver's cab; and a release switch device for performing an operation to release the interference prevention control, wherein the controller releases the interference prevention control according to the operation state of the release switch device, characterized in that, when the release operation by the release switch device is performed while the interference prevention control is being executed, the controller releases the interference prevention control if it is in the operation-disabled state, and continues the interference prevention control when the release operation by the release switch device is performed while the interference prevention control is being executed, if it is in the operation-enabled state. [Effects of the Invention]

[0010] According to the present invention, it is possible to prevent the front work device from colliding with the vehicle body due to erroneous operation of the operating lever when operating the release switch device for releasing interference prevention control. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side view showing the external appearance of an offset hydraulic excavator according to one embodiment of the present invention. [Figure 2] This is a top view showing the external appearance of an offset hydraulic excavator according to one embodiment of the present invention. [Figure 3] This is a schematic plan view showing the detailed configuration of the cab. [Figure 4] This is a hydraulic circuit diagram representing the hydraulic drive system of an offset-type hydraulic excavator. [Figure 5]This is an explanatory diagram showing the control area of ​​the interference prevention control system along with the side view of the hydraulic excavator. [Figure 6] This is an explanatory diagram showing the control area of ​​the interference prevention control system along with the top surface of the hydraulic excavator. [Figure 7] This is a flowchart illustrating the processing procedure executed by the interference limiting control setting unit of the control unit. [Figure 8] This is a flowchart illustrating the processing procedure executed by the interference limiting control execution unit of the control unit. [Figure 9] This is an explanatory diagram showing an example of a calculation table for interference prevention control. [Modes for carrying out the invention]

[0012] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0013] <Overall Summary> Figure 1 shows a side view of the offset hydraulic excavator of this embodiment, and Figure 2 shows a top view.

[0014] As shown in Figures 1 and 2, the offset hydraulic excavator has a vehicle body 103 consisting of an upper rotating body 101f and a lower traveling body 101g, and a multi-jointed front working device 102 that is mounted on the vehicle body 103 so as to be able to tilt up and down and offset to the left and right. The front working device 102 includes a boom 101a connected to the vehicle body 103 so as to be able to move up and down, an arm 101b connected to the boom 101a so as to be able to move up and down, a bucket 101c connected to the arm 101b so as to be able to move, an offset 101d that rotates in the left-right direction (horizontal direction), a cylinder stay 101e, and several other front members.

[0015] The base end portion of the boom 101a of the front working device 102 is supported by the front central portion of the upper revolving structure 101f so as to be rotatable in the vertical direction, the base end portion of the offset 101d is connected to the upper end portion of the boom 101a so as to be rotatable in the left-right direction, the front portion of the cylinder stay 101e is connected to the tip portion of the offset 101d so as to be rotatable in the left-right direction, the base end portion of the arm 101b is connected to the tip portion of the cylinder stay 101e so as to be rotatable in the front-rear direction, and the bucket 101c is connected to the tip portion of the arm 101b so as to be rotatable in the vertical direction.

[0016] The boom 101a, arm 101b, bucket 101c, offset 101d, upper revolving structure 101f, and lower traveling structure 101g are driven by the boom cylinder 3a, arm cylinder 3b, bucket cylinder 3c, offset cylinder 3d, swing motor 3e (see FIG. 4 described later), and left and right traveling motors 3f and 3g, respectively.

[0017] As shown in FIG. 2, on the side opposite to the offset cylinder 3d of the offset 101d, the side surface of the upper end portion of the boom 101a and the side surface of the cylinder stay 101e are connected by the rod 101k via the connecting members 101h and 101j, respectively, and the offset 101d, the rod 101k, the upper end portion of the boom 101a, and the connecting member 101j constitute a parallel link mechanism. The upper revolving structure 101f has a cab 104 (operator's cab) on which an operator rides. Note that the operator's cab is not limited to a box-shaped structure like the cab 104, and may be a so-called canopy-specification operator's cab with a roof shape. Even in this case, the attachment may interfere with the roof member constituting the canopy and various interior parts (travel levers, monitors, etc.) arranged under the canopy, and interference prevention control may be installed. The method according to the present embodiment can also be applied to such a case.

[0018] A blade 101m is connected to the front portion of the lower traveling structure 101g so as to be rotatable in the vertical direction, and the blade 101m is driven by a blade cylinder (not shown).

[0019] <Cab> Figures 3(a) and 3(b) show schematic plan views illustrating the detailed configuration of the cab 104. Figure 3(a) is a plan view without the operator M (operator) on board, and Figure 3(b) is a plan view with the operator M on board. In Figures 3(a) and 3(b), the cab 104 is equipped with a left travel lever 4f and a right travel lever 4g, among other things. For example, moving the left travel lever 4f forward or backward can drive the left track 101ga of the lower running body 101g forward or backward, and moving the right travel lever 4g forward or backward can drive the right track 101ga forward or backward.

[0020] Furthermore, the cab 104 is equipped with a driver's seat 210, a left console device 211, and a right console device 224, among other things. The left console device 211 is located to the left of the driver's seat 210. The right console device 224 is located to the right of the driver's seat 210 on the opposite side.

[0021] The right console device 224 includes a right operating lever 225 located inside the cab 104 and a switch box 267 equipped with multiple switches. The right operating lever 225 functions as an operating lever 4a (see Figure 4 below) for operating the boom 101a, which is the front working device 102, and an operating lever 4c (see Figure 4 below) for operating the bucket 101c, which is the front working device 102. For example, moving the right operating lever 225 forward and backward can perform boom lowering and boom raising operations, and moving it left and right can perform bucket clouding and bucket dumping operations.

[0022] The switch box 67 includes an engine control dial for operating the rotational speed of the engine 202 (prime mover), a key switch 213 for starting the engine 202, and a rotary switch for detailed settings of various state variables, including the pressure of the hydraulic oil in the hydraulic system.

[0023] The left console device 211 has a left operating lever 214 and a shut-off lever 43 located inside the cab 104. The left operating lever 214 functions as an operating lever 4b (see Figure 4 below) for operating the arm 101b, which is the front working device 102, and an operating lever 4e (see Figure 4 below) for rotating the upper rotating body 101f. For example, moving the left operating lever 214 forward and backward can perform arm dumping and arm clouding operations, and moving it left and right can perform left and right rotation operations. Although not shown in the illustration, a blade operating lever is also provided in the left side of the cab 104.

[0024] <Shut-off lever> The shut-off lever 43 is located inside the cab 104 and can switch between an inactive state, which disables the operation of the operating levers 4a to 4g, i.e., the operation of the operating lever devices 4A to 4G (described later), and an active state, which enables the operation of the operating levers 4a to 4g, i.e., the operation of the operating lever devices 4A to 4G (described later). To this end, the shut-off lever 43 rotates between an unlocked position and a locked position. When the shut-off lever 43 is in the locked position, the operator M is permitted to get on and off the cab 104, and when it is in the unlocked position, the operator M is prohibited from getting on and off the cab 104. Also, when the shut-off lever 43 is in the locked position, the operation of the operating levers 4a to 4g (see Figure 4 described later) is disabled, and when it is in the unlocked position, the operation of the operating levers 4a to 4g (see Figure 4 described later) is enabled (details will be described later). In this example, the shut-off lever 43 is located on the left side of the driver's seat 210 in the cab 104, but it is not limited to this location and may be located on the right side. In any case, it is sufficient that the lever is in a position where the operator M can operate it while maintaining a normal driving posture (a body position and angle that allows the operator to operate the left control lever 214 or the right control lever 225 without disrupting their posture).

[0025] <Interference control release switch> Furthermore, in the cab 104, an interference prevention control release switch (= release switch device; hereinafter simply referred to as the release switch) 53 is provided on the left rear side of the driver's seat 210 for performing the operation to release the interference prevention control described later. In this example, the release switch 53 has an OFF state (first state) in which it does not output a release signal for interference prevention control to the control unit 32, and an ON state (second state) in which it outputs a release signal to the control unit 32. It is an alternate-operation switch that alternates between the ON state and the OFF state each time it is pressed. That is, if a press operation (= first operation, i.e., a press operation that transitions from the first state to the second state) is performed in the OFF state, it transitions to the ON state, and if a press operation (= second operation, i.e., a new press operation that transitions from the second state to the first state) is performed in the ON state, it transitions to the OFF state. When the release switch 53 is turned ON by the first operation described above, the system can transition to the release state of the interference prevention control (see S30 in Figure 7 described later). After the transition, the release state of the interference prevention control is maintained at least until it is turned OFF by the second operation described above (in this example, until the new pressing operation described above is performed). In other words, when interference prevention control is executed and the operation of the front work device 102 is stopped in stop area B or prohibited area C, and a press operation is performed to move the release switch 53 from the OFF state to the ON state, if the operation is invalid, the control unit 32 releases the interference prevention control, and then maintains the released state of the interference prevention control until a press operation is performed to move the release switch 53 from the ON state to the OFF state.

[0026] <Hydraulic drive system> Figure 4 is a hydraulic circuit diagram showing the hydraulic drive system of an offset-type hydraulic excavator according to this embodiment. In Figure 4, the hydraulic drive system of the offset hydraulic excavator includes the engine 202, an engine controller (E-ECU) 204 that controls the engine 202, a hydraulic pump 2 as the main pump driven by the engine 202, a boom cylinder 3a, an arm cylinder 3b, a bucket cylinder 3c, and an offset cylinder 3d that are driven by the pressurized oil from the hydraulic pump 2 and drive the front member, a plurality of actuators including a slewing motor 3e and left and right travel motors 3f, 3g, operating lever devices 4A to 4G (operating devices) provided corresponding to each of these hydraulic actuators 3a to 3g and equipped with operating levers 4a to 4g for operating the front work device 102 and the vehicle body 103, a plurality of control valves 5a to 5g connected between the hydraulic pump 2 and the plurality of hydraulic actuators 3a to 3g, which are switched from a neutral position by the command pilot pressure of the operating lever devices 4A to 4G and control the flow of pressurized oil supplied to and discharged from the hydraulic actuators 3a to 3g, and a main relief valve (not shown) as a safety valve. Although not shown in Figure 4, the parts involved in driving the blade cylinder are also included in the hydraulic drive system.

[0027] The operating lever devices 4A to 4G are hydraulically pilot-operated with built-in remote control valves (pressure reducing valves). They are connected to the discharge oil passage 7a (pilot discharge line) of the pilot pump 7 via pilot pressure supply oil passages 7b1 and 7b2. Based on the hydraulic pressure (primary pilot pressure) generated by the pilot pump 7, they generate command pilot pressure (secondary pilot pressure) corresponding to the amount and direction of operation of the operating levers 4a to 4g operated by the operator. The boom operating lever device 4A and the arm operating lever device 4B are connected to the pilot pressure supply oil passage 7b1, while the other operating lever devices 4C to 4G are connected to the pilot pressure supply oil passage 7b2. Note that the pilot pressure supply oil passages 7b1 and 7b2 are sometimes collectively referred to simply as "pilot pressure supply oil passage 7b".

[0028] These command pilot pressures are guided via pilot lines 10a, 10b to 16a, 16b (pilot lines) to the hydraulic drive units 20a, 20b to 26a, 26b of the corresponding control valves 5a to 5g. The discharge oil passage 7a of the pilot pump 7 is equipped with a pilot relief valve (not shown) that maintains a constant discharge pressure of the pilot pump 7.

[0029] Furthermore, the hydraulic drive system shown in Figure 4 includes angle sensors 31a, 31b, and 31c, which are provided at the pivot points of the boom 101a, arm 101b, and offset 101d respectively, and which detect the rotation angles as state quantities related to the position and attitude of the front work device 102; a control unit 32 (controller) that receives signals from the angle sensors 31a, 31b, and 31c and performs calculation processing for interference prevention control; and a pilot line 10a, 10b, 11a, 13a, 13b, which outputs from the control unit 32. The system includes electromagnetic proportional pressure reducing valves 33a, 33b, 33c, 33d, and 33e driven by an electrical signal (command signal), an electromagnetically controlled shut-off valve 34 positioned between the discharge oil passage 7a of the pilot pump 7 and the pilot pressure supply oil passage 7b, the release switch 53, a key switch 213, a warning device 60 that appropriately alerts the operator, the shut-off lever 43, a shut-off valve 160 provided in the pilot pressure supply oil passage 7b2, and an electromagnetic switching valve (electromagnetic switching valve) 150 for increasing arm speed.

[0030] <Shut-off valve / Solenoid switching valve for increasing arm speed> The shut-off valve 160 is an electromagnetic switching valve that can be switched according to a command signal input from the control unit 32, and can supply the pilot primary pressure from the discharge oil passage 7a of the pilot pump 7 only to the boom operating lever device 4A and the arm operating lever device 4B, while shutting off the pilot primary pressure to the other operating lever devices 4C, 4D, 4E, 4F, and 4G.

[0031] The arm speed-increasing electromagnetic switching valve 150 is installed in the connecting pipeline 11c that connects the pilot pressure supply oil passage 7b and the pilot line 11b of the arm control valve 5b to the switching position that supplies pressurized oil to the rod side of the arm cylinder 3b. Normally, the arm speed-increasing electromagnetic switching valve 150 is switched to the upper switching position shown in the figure by a command signal (OFF signal) output from the control unit 32, in which case the connecting pipeline 11c is shut off. When the command signal (OFF signal) output from the control unit 32 is switched to an ON signal, the arm speed-increasing electromagnetic switching valve 150 is switched to the lower position shown in the figure, connecting the pilot pressure supply oil passage 7b and the pilot line 11b, and making it possible to increase the pilot pressure supplied to the pilot line 11b.

[0032] <Solenoid proportional pressure reducing valve> The electromagnetic proportional pressure reducing valves 33a, 33b, 33c, 33d, and 33e reduce the command pilot pressure generated by the operating lever devices 4D, 4A, and 4B in accordance with the command signal from the control unit 32, and the reduced command pilot pressure is guided via the pilot lines 13a, 13b, 10a, 10b, and 11a to the hydraulic drive units 23a, 23b, 20a, 20b, and 21a of the control valves 5d, 5a, and 5b.

[0033] <Shut-off valve> When the shut-off lever 43 is in the unlocked position, the shut-off valve 34 is switched to the position shown on the left in Figure 4 by an ON signal output from the control unit 32. In this case, the discharge pressure of the pilot pump 7 is led as the primary pressure to the pilot pressure supply oil passages 7b1 and 7b2, and the operating lever devices 4A to 4G can generate the commanded pilot pressure by operating their respective operating levers 4a to 4g, thereby enabling the operation of the operating lever devices 4A to 4G (operating devices). In other words, the operation of the operating levers 4a to 4g is enabled. When the shut-off lever 43 is in the locked position, the shut-off valve 34 is switched to the position shown on the right in Figure 4 by an OFF signal output from the control unit 32, thereby disconnecting the connection between the discharge oil passage 7a of the pilot pump 7 and the pilot pressure supply oil passages 7b1 and 7b2, and connecting the pilot pressure supply oil passages 7b1 and 7b2 to the tank. As a result, the operating lever devices 4A to 4G are unable to generate commanded pilot pressure even when the operating levers 4a to 4g are operated, and the operation of the operating lever devices 4A to 4G (operating devices) is disabled. In other words, the operation of the operating levers 4a to 4g is disabled. In this case, all of the hydraulic actuators become inoperable. As a result, all operations of the hydraulic excavator stop.

[0034] <Control area> Figures 5 and 6 show the control area of ​​the interference prevention control performed by the control unit 32. Figure 5 is an explanatory diagram showing the control area together with the side of the hydraulic excavator, and Figure 6 is an explanatory diagram showing the control area together with the top surface of the hydraulic excavator. In Figures 5 and 6, in this embodiment, a deceleration area A, a stopping area B, and a prohibited area C are set sequentially around the cab 104, from the outside to the inside. The deceleration region A is a region in which the operating speed of the front work device 102 is reduced by reducing the operating speed of the driven front member. The stopping region B is a region in which the operation of the front work device 102 is stopped by stopping the operation of the driven front member. The restricted region C is a region in which the entire operation of the hydraulic excavator is stopped by disabling the hydraulic drive system if the front work device 102 enters the restricted region C beyond the stopping region B. In this invention, the setting of deceleration region A and the deceleration control using deceleration region A may be omitted.

[0035] <Main parts of the embodiment> The essential part of this embodiment is that when interference prevention control is performed and the operation of the front work device 102 is stopped in at least the stop area B or the prohibited area C, and a release operation is performed using the release switch 53, if the operation is in an invalid state, the control unit 32 releases the interference prevention control. If interference prevention control is performed and the operation of the front work device 102 is stopped in at least the stop area B or the prohibited area C, and a release operation is performed using the release switch 53, if the operation is in an valid state, the control unit 32 continues to execute the interference prevention control. Accordingly, the control unit 32 functionally includes two parts: an interference prevention control setting unit 32A and an interference prevention control execution unit 32B.

[0036] <Processing by the interference prevention control setting unit> First, the control procedure executed by the interference prevention control setting unit 32A of the control unit 32 of this embodiment to realize the above method will be explained with reference to the flowchart in Figure 7. The flow shown in Figure 7 is executed periodically, for example, at predetermined intervals.

[0037] In Figure 7, first in S5, it is determined whether the aforementioned release switch 53 is in the ON state at this point. If it is in the OFF state, the result is NO, and the processing in this flow ends. If it is in the ON state, the result is YES, and the process moves on to S10.

[0038] In S10, it is determined whether the release switch 53 was in the OFF state during the previous execution (the execution in the previous cycle). If it was in the ON state (i.e., it was in the ON state during the previous execution and has not been pressed since), the result is NO, and the processing in this flow ends. If it was in the OFF state (i.e., it was in the OFF state during the previous execution and was pressed during this execution, turning it into the ON state), the result is YES, and the process proceeds to S15.

[0039] In S15, it is determined whether the shut-off lever 43 is in the locked position or not. If it is in the unlocked position, the result is NO, and the processing in this flow ends. If it is in the locked position, the result is YES, and the process moves to S20. In other words, if the shut-off lever 43 is in the unlocked position (S15: NO), the transition to the release state of the interference prevention control in S30 does not occur even in the execution state of the first operation described above.

[0040] In S20, it is determined whether or not interference prevention control, which will be described in detail later, is currently being performed. If interference prevention control is not being performed, S20 is judged as NO, and the process proceeds to S25. In S25, interference prevention control is enabled. After that, the process in this flow ends.

[0041] On the other hand, if interference prevention control is being performed in S20, S20 is judged as YES, and the process moves to S30. In S30, the interference prevention control is set to be released. That is, if the shut-off lever 43 is in the locked position (S15: YES), the process transitions to the release state of the interference prevention control by the release switch 53 during the execution of the first operation. After S30, the processing in this flow will end.

[0042] <Processing by the interference prevention control execution unit> Next, the control procedure executed by the interference prevention control execution unit 32B of the control unit 32 of this embodiment to realize the above method will be explained with reference to the flowchart in Figure 8. The flow shown in Figure 8 is executed periodically, for example, at predetermined intervals.

[0043] In Figure 8, first, in S35, it is determined whether the interference prevention control by the interference prevention control setting unit 32A is set to deactivate (see S30 in Figure 7). If the interference prevention control is set to enable rather than deactivate (see S25 in Figure 7), S35 is determined to be NO, and the process proceeds to S40.

[0044] In S40, interference prevention control is performed. Specifically, the following processes are carried out sequentially. First, the position of the bucket 101c is calculated. Specifically, the control unit 32 receives angle signals from the angle sensors 31a, 31b, and 31c, and calculates the position of the bucket 101c from the rotation angles of the boom 101a, arm 101b, and offset 101d detected by the angle sensors 31a, 31b, and 31c, as well as the dimensions of each front member stored in memory (for example, ROM) beforehand. In this case, it is preferable to calculate two positions for the bucket 101c: a first proximity position when the bucket 101c is operated toward the front and top of the cab 104, and a second proximity position when the bucket 101c is offset toward the right side of the cab 104. For example, as shown in Figures 5 and 6 above, the first proximity position is the point closest to the cab 104 on a virtual circle with radius Rb from the pivot point of the bucket 101c to the tip of the bucket, and the second proximity position is, for example, the center of the left side of the bucket 101c as seen from the driver's seat inside the cab 104.

[0045] Subsequently, the following process is executed by applying, for example, the calculation table shown in Figure 9 to the position of bucket 101c obtained as described above. In Figure 9, the horizontal axis represents the distance D between the first or second proximity position of bucket 101c and the front reference line F of cab 104 (see Figures 5 and 6), and the vertical axis represents the front-to-back pressure ratio Rp of the electromagnetic proportional pressure reducing valves 33a, 33b, 33c, 33d, and 33e. The relationship between distance D and front-to-back pressure ratio Rp is such that when distance D is greater than or equal to the first set value D1, the front-to-back pressure ratio Rp is 100%, and as distance D becomes less than the first set value D1, the pressure ratio Rp gradually decreases from 100%, and becomes 0% when distance D is less than or equal to the second set value D2.

[0046] In this case, the first setting value D1 corresponds to boundary line E1 in Figures 5 and 6, and the second setting value D2 corresponds to boundary line E2 in Figures 5 and 6. On the side smaller than the second setting value D2 (closer to the origin) is the third setting value D3. This third setting value D3 corresponds to boundary line E3 in Figures 5 and 6. Furthermore, the region above the first setpoint D1 (farthest from the origin) is the uncontrolled region X, the region between the first setpoint D1 and the second setpoint D2 corresponds to the deceleration region A, the region between the second setpoint D2 and the third setpoint D3 corresponds to the stop region B, and the region below the third setpoint D3 corresponds to the prohibited region C. These deceleration region A, stop region B, and prohibited region C form the controlled region Y. The calculation table shown in Figure 9 is stored, for example, in the memory (not shown) of the control unit 32.

[0047] The interference prevention control execution unit 32B of the control unit 32 calculates the front-to-back pressure ratio Rp of the electromagnetic proportional pressure reducing valves 33c, 33d, and 33e by referring to the interference prevention control limit value calculation table shown in Figure 9, and outputs a control current corresponding to this front-to-back pressure ratio Rp as an electrical signal to the electromagnetic proportional pressure reducing valves 33a and 33b. Furthermore, the interference prevention control execution unit 32B of the control unit 32 calculates the front-to-back pressure ratio Rp of the electromagnetic proportional pressure reducing valves 33a and 33b by referring to the calculation table shown in Figure 9, based on the distance D between the second position of the bucket 101c and the reference line F on the side of the cab 104, and outputs a control current corresponding to this front-to-back pressure ratio Rp as an electrical signal to the electromagnetic proportional pressure reducing valves 33a and 33b.

[0048] As a result, when the tip (first proximity position) or left side (second proximity position) of the bucket 101c enters the deceleration region A by operating at least one front member of the front work device 102, interference prevention control is executed to control the relevant electromagnetic proportional pressure reducing valves 33a, 33b, 33c, 33d, and 33e to reduce the command pilot pressure, gradually decreasing the operating speed of the front member, thereby gradually decelerating the operation of the front work device 102.

[0049] Furthermore, when the tip or left side of the bucket 101c exceeds the deceleration region A and reaches the stopping region B, the interference prevention control execution unit 32B of the control unit 32 performs interference prevention control and outputs a control current corresponding to a front-to-rear pressure ratio of 0% based on the interference prevention control limit value calculation table shown in Figure 9, completely closing the corresponding electromagnetic proportional pressure reducing valves 33a, 33b, 33c, 33d, and 33e to reduce the command pilot pressure to the tank pressure and stop the operation of the front member.

[0050] Furthermore, at this time, the interference prevention control execution unit 32B of the control unit 32 monitors whether the front work device 102 (in this embodiment, the first proximity position or the second proximity position of the bucket 101c) has entered the prohibited area C. If it is determined that the front work device 102 has entered the prohibited area C, interference prevention control is executed and an ON signal is output to the shut-off valve 34, which disconnects the connection between the discharge oil passage 7a of the pilot pump 7 and the pilot pressure supply oil passage 7b. Alternatively, the interference prevention control execution unit 32B may, in the same manner as above, completely close all of the electromagnetic proportional pressure reducing valves 33a, 33b, 33c, 33d, and 33e to reduce the commanded pilot pressure to the tank pressure.

[0051] Once S40 is completed as described above, the process moves on to S70, which will be described later.

[0052] On the other hand, if the interference prevention control is set to be disabled in S35 (see S30 in Figure 7), S35 is judged as YES, and the process proceeds to S45.

[0053] In S45, while the interference prevention control is deactivated based on the release switch 53, the interference prevention control execution unit 32B reduces the rotational speed of the engine 202 by outputting a control signal to the engine controller 204 in response to the deactivated state of the interference prevention control, thereby reducing the rotational speed of the engine 202 (low idle). This slows down the drive speed of multiple hydraulic actuators (boom cylinder 3a, arm cylinder 3b, bucket cylinder 3c, offset cylinder 3d, swing motor 3e, and left and right travel motors 3f, 3g). Note that the drive speed of the hydraulic actuators may be slowed down not only by controlling the rotational speed of the engine 202 as described above, but also by limiting the pilot primary pressure from the pilot pump 7 or the pilot pressure to the control valves 5a to 5g, etc. The process then moves to S50.

[0054] In S50, the interference prevention control execution unit 32B outputs a command signal to the shut-off valve 160 located in the pilot pressure supply oil passage 7b2, driving the shut-off valve 160 to the shut-off state. As a result, the pilot primary pressure from the discharge oil passage 7a of the pilot pump 7 is supplied only to the boom operating lever device 4A and the arm operating lever device 4B, and not to the other operating lever devices 4C, 4D, 4E, 4F, and 4G. The process then moves to S55.

[0055] In S55, similar to S15 in Figure 7, it is determined whether the shut-off lever 43 is in the locked position. If it is in the locked position, the result is YES, and the process proceeds to S70, which will be described later. If it is in the unlocked position, the result is NO, and the process proceeds to S60.

[0056] In S60, it is determined whether the position of the bucket 101c is within the stopping area B or the prohibited area C. Specifically, the first proximity position of the bucket 101c is determined by the same method as in S40, which is performed by the interference prevention control setting unit 32A, and it is determined whether the distance D between this first proximity position and the reference line F (see Figures 5 and 6) in front of the cab 104 is less than D2. The reason why the distance D is determined by comparison with D2 is as follows. That is, when the position of the bucket 101c is within the stop region B and the prohibition region C, in principle, the operator cannot move the front working device 102, but within the deceleration region A (D2≦D<D1), the operator can operate the front working device 102. Therefore, from the viewpoint that it is sufficient to retract the front working device 102 at least to a region where it can move automatically, the process of S65 described later is performed when the position of the bucket 101c is in the stop region B or the prohibition region C. If distance D≧D2, S60 makes a NO determination, and the process proceeds to S70 described later. If distance D<D2, S60 makes a YES determination, and the process proceeds to S65.

[0057] In S65, the interference prevention control execution unit 32B outputs a command signal to the arm speed-increasing electromagnetic switching valve 150, so that the arm speed-increasing electromagnetic switching valve 150 causes the connection pipeline 11c to communicate. Thereby, the pilot pressure from the pilot pump 7 is guided to the hydraulic drive unit 21b of the arm control valve 5b via the pilot pressure supply oil passage 7b, and the arm control valve 5b is switched to the right position in the drawing. That is, as shown in FIGS. 4 and 1, the arm cylinder 3b is a hydraulic cylinder that operates the arm 101b in the dump direction by supplying pressure oil to the rod side and driving to the contraction side, and operates the arm 101b in the crowd direction by supplying pressure oil to the bottom side and driving to the extension side. As a result, by switching the arm control valve 5b to the right position in the drawing as described above, pressure oil is supplied to the rod side, so that the movement of the arm 101b in the dump direction is automatically accelerated. Thereafter, the process proceeds to S70.

[0058] In S70, it is determined whether the engine 202 is running, specifically whether the key switch 213 is not turned OFF and remains in the ON state. If the key switch 213 is turned OFF, S70 is determined to be NO, and the process in this flow ends. As long as the key switch 213 is not turned OFF and remains in the ON state, S70 is determined to be YES, and the process returns to S35 as described above, and the same procedure as above is repeated.

[0059] <Effects of the Embodiment> In the offset hydraulic excavator of this embodiment, a release switch 53 is provided for releasing the interference prevention control of the control unit 32. As a basic control function of the control unit 32, the release state of the interference prevention control is maintained from the time the first operation is performed on the release switch 53 until the second operation is performed. On the other hand, in this embodiment, the control unit 32 has a function to release the interference prevention control when the release switch 53 is activated while interference prevention control is being performed, if the operation is in an invalid state, and to continue the interference prevention control when the release switch 53 is activated while interference prevention control is being performed, if the operation is in an active state. In other words, if the shut-off lever 43, which is located on either the left or right side of the driver's seat 210, is in the unlocked position, the system will not, exceptionally, transition to the release state of the interference prevention control by the release switch 53 even when the first operation is being performed. If the shut-off lever 43 is in the locked position, the system will transition to the release state of the interference prevention control by the release switch 53 when the first operation is being performed. Therefore, if, for example, the operator M wants to manually move the front work device 102, which has stopped in the stopping area B, etc., due to the execution of interference prevention control, out of the stopping area B, etc., the operator M should perform the operation in the following sequence. First, in the normal driving position, the shut-off lever 43 located next to the driver's seat 210 is set to the locked position. This disables operation by the operating lever 4a, etc. Subsequently, the release switch 53 is operated for the first time to switch to the release state of the interference prevention control. As a result, the interference prevention control is disabled, but operation of the operating lever 4a, etc., is still invalid. Therefore, even if the operator's posture is disrupted while operating the release switch 53 and any part of their body touches the operating lever 4a, etc., the front work device 102 will not malfunction. Then, the operator returns to the normal driving position and unlocks the shut-off lever 43 next to the driver's seat 210 again. This makes the operation of the control levers 4a, etc. (however, in this embodiment, only the operation of the boom control lever 4a and the arm control lever 4b) effective, so the operator M can move the control levers 4a, etc. as appropriate to move the front work device 102 outside the stopping area B, etc. As described above, according to this embodiment, when releasing the interference prevention control by operating the release switch 53 in order to move the front work device 102 outside the stopping area B, etc., it is possible to prevent the front work device 102 from colliding with the upper rotating body 101f and the lower traveling body 101g due to erroneous operation of the operating lever 4a, etc.

[0060] Furthermore, in this embodiment, the release switch 53 is an alternate-operation switch. This allows the operator M to operate the release switch 53 to release the interference prevention control with just one press (= first operation), and (if the shut-off lever 43 is in the locked position) transition to the release state of the interference prevention control, and even if the operator releases their hand afterward, the release state can be maintained.

[0061] Furthermore, in this embodiment, the control unit 32, in particular, reduces the rotational speed of the engine 202 while the interference prevention control is released based on the release switch 53, thereby slowing down the drive speed of the multiple hydraulic actuators (in this example, the boom cylinder 3a and arm cylinder 3b that can be operated when released). Therefore, when operator M operates the control lever 4a, etc., as described above to move the front work device 102 outside the stopping area B, etc., it is possible to ensure complete safety in terms of preventing collision with the cab 104. In addition to the method of reducing the rotational speed of engine 202, the driving speed of the hydraulic actuators (boom cylinder 3a, arm cylinder 3b) may also be reduced by restricting the pilot pressure to the control valves 5a and 5b using electromagnetic proportional pressure reducing valves 33c, 33d, and 33e, similar to the deceleration control described above.

[0062] Furthermore, when operator M operates the control lever 4a, etc., as described above to move the front work device 102 outside the stopping area B, etc., it is sufficient to make the boom 101a and arm 101b movable, and it is not necessary to make the other front members (bucket 101c, offset 101d, cylinder stay 101e) movable. In this embodiment, the control unit 32, in particular, stops all operation of the front work device 102 as interference prevention control. Based on the release switch 53, the interference prevention control is released, and the shut-off lever 43 switches from an inoperable state to an operable state. While the front work device 102 is in a predetermined area, the operation of the boom 101a and arm 101b is permitted, and the operation of the other front work devices is stopped. Specifically, while the interference prevention control is released, the control unit 32 outputs a command signal to the shut-off valve 160 to shut off the pilot primary pressure to the other operating lever devices 4C to 4G. This prevents the other front members (bucket 101c, offset 101d, cylinder stay 101e) from moving, ensuring complete safety from the viewpoint of preventing collision with the cab 104. Note that the method is not limited to the above method, and other methods are acceptable as long as the other front members (bucket 101c, offset 101d, cylinder stay 101e) can be prevented from moving.

[0063] Furthermore, in this embodiment, the control unit 32 is switched from an inoperable state to an operable state by the shut-off lever 43 when the interference prevention control is released based on the release switch 53, and when the front work device 102 has entered a predetermined area, the arm 101b is automatically moved in the dump direction. Specifically, after the operator M first operates the release switch 53 with the shut-off lever 43 in the locked position as described above to switch to the release state of the interference prevention control, and then moves the shut-off lever 43 to the unlocked position, the movement of the arm 101b in the dump direction is automatically accelerated by the increase in pilot pressure from the electromagnetic switching valve 150. As a result, the front work device 102 can be automatically and quickly moved out of the stop area B, etc., without the operator M having to operate the operating lever 4a, etc. as described above. Note that the method is not limited to the above method, and other methods are also acceptable as long as the arm 101b can be automatically moved in the dump direction.

[0064] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from its spirit and technical idea. Such modifications will be described in order below. The same reference numerals are used for parts equivalent to those in the above embodiments, and their descriptions will be omitted or simplified as appropriate.

[0065] (1) When using a momentary release switch In the above embodiment, an alternate-type switch was used as the release switch 53, but it is not limited to this, and a so-called momentary-type switch may also be used. Such modifications will be described below.

[0066] In this modified example, the release switch 53 is a switch having a first position (position before pressing) in which it does not output a release signal for interference prevention control to the control unit 32, and a second position (position after pressing) in which it outputs a release signal to the control unit 32. The first operation is a pressing operation from the first position to the second position, and the second operation is an operation to release the press after pressing to the second position and return to the first position.

[0067] In this modified example, when the first operation is performed to move the release switch 53 from the first position to the second position while interference prevention control is being executed, if the operation is in an invalid state, the control unit 32 releases the interference prevention control, and then the release switch 53 moves from the second position to the first position (i.e., the release switch 53 is released and returned to the first position), and the release state of interference prevention control is maintained until predetermined conditions are met.

[0068] The above-mentioned predetermined conditions include, for example, the stopping operation of the engine 202, that is, the turning off of the key switch 213, or the retraction of the front work device from the stopping area B and the prohibited area C.

[0069] In other words, after the release operation is performed, the interference prevention control remains deactivated until the engine 202 is stopped or the front work device 102 is moved out of the stopping area B and the prohibited area C. On the other hand, when the engine 202 is stopped or the front work device 102 is moved out of the stopping area B and the prohibited area C, the interference prevention control is restored. This prevents, for example, a driver who has released the interference prevention control but has not moved the front work device 102 out of the stopping area B and the prohibited area C before taking a break, and then restarting the engine 202, from forgetting that the front work device 102 is in a state where it is highly likely to collide with the vehicle body, and accidentally causing the front work device 102 to collide with the vehicle body. It also prevents a collision between the front work device 102 and the vehicle body if the front work device re-enters the stopping area B or the prohibited area C, without the interference prevention control being executed. For example, if the release switch 53 is not pressed while the key switch 213 is ON when starting the engine 202, the interference prevention control is released only while the release switch 53 is pressed down. On the other hand, if the release switch 53 is pressed while the key switch 213 is ON when starting the engine 202, the control unit 32 controls the release of the release switch 53, maintaining the release state of the interference prevention control.

[0070] If the release switch 53 is a momentary switch, and the configuration is such that the interference prevention control is released simply by performing the first operation (= pressing from the first position to the second position), then the momentary switch must be pressed down with one hand while the operating lever is operated with the other hand. In other words, after the first operation, when the hand is released and the switch is returned from the second position to the first position, the release state of the interference prevention control is resolved and the interference prevention control is reactivated.

[0071] In this modified example, in response to the above, the control unit 32 maintains the deactivated state of the interference prevention control even after the operator releases their hand and returns to the first position as described above, until predetermined conditions are met. This allows the operator M to prevent collisions between the front work device 102 and the upper rotating body 101f and lower traveling body 101g due to erroneous operation of the operating lever 4a, etc., when deactivating the interference prevention control using the same operating procedure as in the above embodiment, while also enabling the front work device 102 to be moved out of the stopping area and the prohibited area C.

[0072] In other words, for example, if the operator M wants to manually move the front work device 102, which has stopped in the stopping area B, etc., due to interference prevention control, out of the stopping area B, etc., the operator M should perform the operation in the following sequence. First, in the normal driving position, the shut-off lever 43 located next to the driver's seat 210 is set to the locked position. This disables operation by the operating lever 4a, etc. Subsequently, while satisfying the aforementioned predetermined conditions (in the example above, while turning on the key switch 213), the release switch 53 is performed in the first operation (pressing it from the first position to the second position). This allows the system to transition to the release state of the interference prevention control. Then, the driver returns to the normal driving position and unlocks the shut-off lever 43 next to the driver's seat 210. This makes the operation of the control lever 4a etc. effective, so the operator M can move the control lever 4a etc. as appropriate to move the front work device 102 outside the stopping area B etc.

[0073] (2) Others The above explanation has been based on the application of the present invention to an offset-type hydraulic excavator as an example, but it is not limited to this. That is, even in conventional hydraulic excavators that are not offset-type, there is a possibility of interference with the cab when large attachments such as breakers or magnets are attached, or when a large-capacity bucket is used. When cab interference prevention control is installed in these models, the same method as in the above embodiment can be applied, and the same effects as described above can be obtained. Furthermore, the present invention can also be applied to accelerator pedals and steering handles in wheeled excavators and wheel loaders, in which case the operating device includes multiple operating levers, attachment operating pedals, driving pedals, etc.

[0074] Furthermore, the arrows on the signal lines shown in Figure 4 represent only one example of signal flow and do not limit the direction of signal flow.

[0075] Furthermore, the flowcharts shown in Figures 7 and 8 do not limit the present invention to the procedures shown in the flowcharts above, and additional or deleted procedures or changes in order are permitted without departing from the spirit and technical idea of ​​the invention. [Explanation of Symbols]

[0076] 2. Hydraulic pump 3a Boom cylinder (hydraulic actuator) 3b Arm cylinder (hydraulic actuator) 4a~4g Operating lever (operating device) 5a~5g control valve 7. Pilot pump 7a Discharge oil line (pilot discharge pipe) 7b1, 7b2 Pilot pressure supply oil passage 10a~16a Pilot line (pilot conduit) 10b~16b Pilot line (pilot conduit) 11c connecting conduit 20a~26a Hydraulic drive unit 20b~26b Hydraulic drive unit 32 Control Unit (Controller) 32A Interference prevention control setting unit 32B Interference prevention control execution unit 33a~33e Electromagnetic proportional pressure reducing valve 34 Shut-off valve 43 Shut-off lever 53 Release switch (release switch device) 101a Boom (working component) 101b Arm (working component) 101c Bucket (working component) 101f Upper rotating body 101g Lower running body 102 Front work device 103 Car body 104 Cab (driver's cab) 150 Arm Speed-Increasing Solenoid Switching Valve (Solenoid Switching Valve) 160 Shut-off valve 202 Engine (prime mover) 210 Driver's seat 213 Key Switches 214 Left control lever 225 Right control lever A deceleration area B Stop area (predetermined area) C Prohibited area (specified area) M Operator Y control region

Claims

1. The car body and, The vehicle body is provided with a front work device that is movable in an upward and downward direction and includes a plurality of front members, The vehicle body is provided with a driver's cab having a driver's seat inside, An operating device for operating the front work device, located in the driver's cabin, A shut-off lever is located in the driver's cabin and is capable of switching between an operation-disabled state that disables the operation of the control device and an operation-enabled state that enables the operation of the control device. A controller that performs interference prevention control to stop the operation of the front work device when the front work device enters a predetermined area set around the driver's cab, The device includes a release switch for performing the operation to release the interference prevention control, In a construction machine, the controller releases the interference prevention control according to the operating state of the release switch device. The aforementioned controller, When the release operation is performed by the release switch device while the interference prevention control is being executed, if the operation is in an invalid state, the interference prevention control is released. When the release operation is performed by the release switch device while the interference prevention control is being executed, if the operation is in an effective state, the interference prevention control is continued. A construction machine characterized by the following features.

2. In the construction machine described in claim 1, The release switch device is an alternate-operation type switch having a first state in which it does not output the release signal for the interference prevention control to the controller, and a second state in which it outputs the release signal to the controller. The aforementioned controller, When the aforementioned interference prevention control is being executed, if a press operation is performed on the release switch device that transitions it from the first state to the second state, and the operation is in an invalid state, the interference prevention control is released, and the release state of the interference prevention control is maintained thereafter until a press operation is performed on the release switch device that transitions it from the second state to the first state. A construction machine characterized by the following features.

3. In the construction machine described in claim 1, The release switch device is This is a momentary switch having a first position in which the release signal for the interference prevention control is not output to the controller, and a second position in which the release signal is output to the controller. The aforementioned controller, When the interference prevention control is being performed and a pressing operation is performed to move the release switch device from the first position to the second position, if the operation is in an invalid state, the interference prevention control is released, and thereafter the release switch device moves from the second position to the first position and the release state of the interference prevention control is maintained until predetermined conditions are met. The aforementioned predetermined conditions are: At least one of the following: stopping the prime mover, or moving the front work device out of the predetermined area. A construction machine characterized by the following features.

4. In the construction machine described in claim 1, A hydraulic pump that supplies pressurized oil to a plurality of hydraulic actuators for driving the plurality of front members, A prime mover that drives the aforementioned hydraulic pump, It has, The aforementioned controller, While the interference prevention control is deactivated based on the aforementioned deactivation switch device, the rotational speed of the prime mover is reduced. A construction machine characterized by the following features.

5. In the construction machine described in claim 1, The aforementioned multiple front members are, It includes a boom connected to the vehicle body so as to be able to move up and down, and an arm connected to the boom so as to be able to move up and down, The aforementioned controller, As the interference prevention control, all operations of the front work device are stopped. With the interference prevention control released based on the release switch device, the shut-off lever switches from the disabled operation state to the enabled operation state, and while the front work device is in the predetermined area, the operation of the boom and the arm is permitted, and the operation of other front work devices is stopped. A construction machine characterized by the following features.

6. In the construction machine described in claim 1, The aforementioned multiple front members are, It includes a boom connected to the vehicle body so as to be able to move up and down, and an arm connected to the boom so as to be able to move up and down, The aforementioned controller, When the interference prevention control is released based on the release switch device, and the shutdown lever switches from the disabled operation state to the enabled operation state, and the front work device has entered the predetermined area, the arm is automatically moved in the dumping direction. A construction machine characterized by the following features.

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