JP2011184964A - Excavator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excavator, which gently stops a boom while limiting a movable angle of the boom. <P>SOLUTION: In this excavator 100, a boom angle α of the boom 120 to a machine body 101 is detected, and when the boom 120 is elevated to reach a set boom angle α0 of the boom 120 to the preset machine body 101 by the supply of hydraulic fluid to a boom elevating side oil chamber 131 in a boom cylinder 130a, the supply of hydraulic fluid to the boom elevating side oil chamber 131 is stopped. With a decrease in differential value Δα between the boom angle α and the preset boom angle α0, the decrease rate of supply amount of hydraulic fluid to the boom elevating side oil chamber 131 is increased. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an excavator such as a hydraulic excavator.

  In general, an excavator such as a hydraulic excavator is hydraulically operated by a boom that is swingably provided with respect to a machine body and an arm that is swingably connected to a tip of the boom. An attachment such as a bucket is connected to the section.

  In such excavators, a configuration that limits the work range in order to avoid contact with surrounding objects has been proposed.

  For example, Patent Document 1 discloses a configuration that limits the movable angle of the arm in order to avoid the interference of the bucket with the driver's seat.

Japanese Patent No. 3418127

  However, although the excavator described in Patent Document 1 can limit the movable angle of the arm, it cannot limit the movable angle of the boom. In addition, when the boom ascending speed is high, there is a possibility that the boom cannot be stopped due to inertial force, or excessive vibration may occur due to a sudden stop.

  Then, an object of this invention is to provide the excavator which can stop a boom gently, restrict | limiting the movable angle of a boom.

  In order to solve the above problems, the present invention detects a boom angle of a boom with respect to a machine body, and the boom is raised in advance by supplying hydraulic oil to a boom raising side oil chamber in a boom cylinder. An excavator that stops the supply of hydraulic oil to the boom raising side oil chamber when reaching the set boom angle of the boom with respect to the set machine body, and a difference value between the boom angle and the set boom angle The excavator is characterized in that the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber is increased with a decrease in the hydraulic pressure.

  According to the present invention, as the boom angle approaches the set boom angle, it is possible to reduce the amount of hydraulic oil supplied to the boom raising side oil chamber, thereby gradually increasing the boom angle to the set boom angle. The boom can be stopped. Moreover, in the range which has the allowance to the said setting boom angle with respect to the said boom angle, the deceleration of the raising speed of the said boom can be suppressed, and, thereby, the fall of work efficiency can be prevented.

  In the present invention, it is possible to exemplify an aspect in which a boom angular velocity is calculated based on the boom angle, and a configuration in which the reduction rate of the amount of hydraulic oil supplied to the boom raising side oil chamber is increased as the boom angular velocity is higher.

  In this aspect, the boom can be decelerated in accordance with the boom raising speed when the boom is raised, whereby the boom can be gently stopped up to the set boom angle.

  In the present invention, an example in which the engine rotational speed of the engine is detected and a configuration in which the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber increases as the engine rotational speed increases is illustrated. it can.

  In this aspect, even when the engine speed is large, the boom can be gently and reliably stopped up to the set boom angle.

  In this invention, the aspect which added the structure which detects the hydraulic fluid temperature of hydraulic fluid, and made the reduction | decrease rate of the supply quantity of the hydraulic fluid to the said boom raising side oil chamber small, can be illustrated, so that the said hydraulic fluid temperature is low.

  In this embodiment, when the temperature of the hydraulic oil is low, the fluidity of the hydraulic oil is usually low. Considering this, when the temperature of the hydraulic oil is lower than the specified temperature or lower than the specified temperature, the amount of decrease in the hydraulic oil to the boom raising side oil chamber can be suppressed, thereby preventing the work efficiency from being lowered. can do.

  In the present invention, the boom hydraulic pressure of the boom raising side oil chamber is detected, and the aspect in which the reduction ratio of the amount of hydraulic oil supplied to the boom raising side oil chamber is reduced as the boom hydraulic pressure is higher is exemplified. it can.

  In this aspect, even when the boom raising load when raising the boom is large, the boom can be gently and surely stopped up to the set boom angle.

  In the present invention, crane mode execution means for specifying a function for a crane mode used as a crane is provided, and in the crane mode by the crane mode execution means, a hydraulic pump for circulating hydraulic oil to a hydraulic circuit is provided. A mode to which a configuration for suppressing the total discharge amount is added can be exemplified.

  In this aspect, the boom raising speed in the crane mode can be suppressed.

  In this invention, the aspect which added the structure which suppresses the supply quantity of the hydraulic fluid to the said boom raising side oil chamber in the initial stage of a drive can be illustrated.

  In this aspect, the initial drive of the boom actuator can be performed gently.

  As described above, according to the present invention, as the difference between the boom angle and the set boom angle decreases, the reduction rate of the amount of hydraulic oil supplied to the boom raising side oil chamber increases. As the boom angle approaches the set boom angle, the amount of hydraulic oil supplied to the boom raising side oil chamber can be reduced, and thereby the boom is gently stopped up to the set boom angle. Can do. Moreover, in the range which has the allowance to the said setting boom angle with respect to the said boom angle, deceleration of the raising speed of the said boom can be suppressed, and, thereby, the fall of work efficiency can be prevented.

It is a side view showing a schematic structure of an excavator according to an embodiment of the present invention. It is the front view which looked at the excavator shown in FIG. 1 from the front. It is the top view which looked at the excavator shown in FIG. 1 from the top. It is a hydraulic circuit diagram which shows an example of the hydraulic circuit which supplies hydraulic fluid to the actuator for booms, and the actuator for arms. It is a hydraulic circuit diagram which shows an example of the hydraulic circuit which supplies hydraulic fluid to the actuator for offset. It is a block diagram which shows roughly the system configuration | structure which mainly shows the control part in an excavator. It is a control block diagram which shows the detail of the control structure of the process part in a control part. It is a model side view for demonstrating a boom angle. It is a model rear view for demonstrating an offset angle. It is a schematic side view for explaining a process of calculating a set boom angle when the boom is rotated in a direction in which the boom is raised assuming that the arm is stopped, and (a) is a diagram showing a first maximum allowable angle. (B) is a diagram showing the second maximum allowable angle, and (c) is a diagram showing the third maximum allowable angle. It is a schematic control block diagram of the example of the stop control which stops a boom, Comprising: It is a figure which shows the structural member of the input system of a control part. It is a schematic control block diagram of the example of the stop control which stops a boom, Comprising: It is a figure which shows the structural member of the input system of a control part. It is a schematic control block diagram of the example of the stop control which stops a boom, Comprising: It is a figure which shows the detail of a boom stop means. It is a characteristic view which shows an example of the relationship between a boom angle deviation and the valve opening rate of the electromagnetic proportional pressure reducing valve for booms. It is a characteristic view which shows an example of the valve opening rate of the electromagnetic proportional pressure reducing valve for booms, and a boom command electric current value. It is a characteristic view which shows an example of the relationship between a boom angle deviation and a boom 1st valve opening rate correction ratio. It is a characteristic view which shows an example of the relationship between boom angular velocity and a boom 2nd valve opening rate correction ratio. It is a characteristic view which shows an example of the relationship between a boom angle and a boom link ratio correction factor. It is a characteristic view which shows an example of the relationship between an engine speed and the engine speed correction factor for booms. It is a schematic side view for demonstrating correction | amendment of the protrusion upper limit of the piston in the actuator for booms, Comprising: It is a figure which shows the difference value of a boom angle and a boom upper limit angle.

  Embodiments according to the present invention will be described below with reference to the drawings. The following embodiments are examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

  FIG. 1 is a side view showing a schematic configuration of an excavator 100 according to an embodiment of the present invention. FIG. 2 is a front view of the excavator 100 shown in FIG. 1 as viewed from the front. FIG. 3 is a plan view of the excavator 100 shown in FIG. 1 viewed from above.

  The excavator 100 shown in FIGS. 1 to 3 includes a machine main body 101, a boom 120, a boom actuator 130, an arm 140, and an arm actuator 150.

  The boom 120 is a rotation fulcrum (rotation) along the width direction of the machine main body 101, that is, in the left-right direction (Z-axis direction parallel to the axial direction of the axle in the crawler type traveling device 102). Axis) is provided so as to be swingable about P1.

  The boom actuator 130 is interposed between the machine main body 101 and the boom 120 (a first boom 121 described later), and operates the boom 120. Specifically, the boom actuator 130 includes a boom cylinder 130a and a boom piston 130b. The boom actuator 130 is provided such that the base end portion 130c of the boom cylinder 130a is rotatable about a rotation fulcrum (rotation axis) P2 along the Z-axis direction with respect to the machine body 101. The front end portion 130d of the piston for use 130b is provided so as to be rotatable about a rotation fulcrum (rotation shaft) P3 along the Z-axis direction with respect to the boom 120 (first boom 121). The boom actuator 130 rotates the boom 120 by expanding and contracting by hydraulic pressure.

  The arm 140 is provided so as to be swingable around a rotation fulcrum (rotation shaft) P4 along the Z-axis direction with respect to the tip end portion 123a of the boom 120 (a third boom 123 described later). That is, the arm 140 is pivotally supported by the tip end portion 123a of the third boom 123 on the rotation axis P4.

  The arm actuator 150 is interposed between the boom 120 and the arm 140 and operates the arm 140. Specifically, the arm actuator 150 includes an arm cylinder 150a and an arm piston 150b. The arm actuator 150 is provided such that the base end portion 150c of the arm cylinder 150a is rotatable about a rotation fulcrum (rotation axis) P5 along the Z-axis direction with respect to the boom 120 (third boom 123). The distal end 150d of the arm piston 150b is provided so as to be rotatable with respect to the arm 140 about a rotation fulcrum (rotation axis) P6 along the Z-axis direction. The arm actuator 150 rotates the arm 140 by expanding and contracting by hydraulic pressure. Here, the arm actuator 150 is interposed between the base side of the arm bracket 140 b and the base side of the third boom 123.

  In the present embodiment, the boom 120 has a first boom 121, a second boom 122, and a third boom 123. The boom 120 is configured such that a first boom 121, a second boom 122, and a third boom 123 are connected to the machine body 101 toward the distal end side. The excavator 100 is an offset hydraulic excavator having an offset mechanism that translates the third boom 123 and the arm 140 in the Z-axis direction (width direction) of the machine body 101. In the present embodiment, the excavator 100 further includes an offset member 160 and an offset actuator 170.

  The first boom 121 is provided to be swingable about the rotation axis P <b> 1 with respect to the machine body 101. That is, the first boom 121 is pivotally supported by the machine main body 101 on the rotation axis P1. Specifically, the lower end portion of the first boom 121 extends further downward than the rotation axis P1 to be provided with a rotation axis P3, and the rotation axis provided at the rear portion of the rotation axis P3 and the machine body 101. Boom actuator 130 is interposed between P2 and P2.

  The second boom 122 is in the front-rear direction of the machine body 101 with respect to the tip 121a of the first boom 121 (here, a virtual straight line Q0 perpendicular to the axle connecting the centers of the front and rear axles in the crawler type traveling device 102 (that is, the ground surface). ) Is provided so as to be swingable around a rotation fulcrum (rotation shaft) P7 along the X-axis direction parallel to (). That is, the second boom 122 is pivotally supported by the tip 121a of the first boom 121 on the rotation axis P7. Note that the rotation axis P7 may be directed obliquely depending on the rotation position of the first boom 121. The same applies to the rotation axes P8 to P12 described later.

  In addition, the third boom 123 is provided so as to be swingable around a rotation fulcrum (rotation shaft) P8 along the X-axis direction with respect to the distal end portion 122a of the second boom 122. That is, the third boom 123 is pivotally supported by the distal end portion 122a of the second boom 122 on the rotation axis P8.

  Even if the second boom 122 swings in the Z-axis direction, the offset member 160 moves in the vertical direction of the machine body 101 of the third boom 123 and the arm 140 (the axis of the axle in the crawler type traveling device 102 is perpendicular to the X-axis direction and Are connected between the first boom 121 and the third boom 123 so as to maintain the posture in the Y-axis direction perpendicular to the direction). Specifically, the offset member 160 is a rod-shaped rod member, and one end 160a is provided on the first boom 121 so as to be rotatable about a rotation fulcrum (rotation shaft) P9 along the X-axis direction. The other end 160b is provided on the third boom 123 so as to be rotatable about a rotation fulcrum (rotation shaft) P10 along the X-axis direction. Specifically, a bracket 121b is provided on the left side of the first boom 121 as viewed from the front side on the front side. The bracket 121b of the first boom 121 and the one end 160a of the offset member 160 are pivotally supported by a rotation shaft P9. Further, a bracket 123b is provided on the left side of the third boom 123 as viewed from the front on the base end side so as to project laterally. The bracket 123b of the third boom 123 and the other end 160b of the offset member 160 are pivotally supported by a pivot shaft P10.

  The offset actuator 170 is interposed between the first boom 121 and the second boom 122 and operates the second boom 122. Specifically, the offset actuator 170 includes an offset cylinder 170a and an offset piston 170b. The offset actuator 170 is provided such that the base end portion 170c of the offset cylinder 170a is rotatable about a rotation fulcrum (rotation axis) P11 along the X-axis direction with respect to the first boom 121. A tip portion 170d of the offset piston 170b is provided so as to be rotatable about a rotation fulcrum (rotation shaft) P12 along the X-axis direction with respect to the second boom 122. The offset actuator 170 rotates the second boom 122 by expanding and contracting with hydraulic pressure.

  With this configuration, even when the second boom 122 swings in the width direction (Z-axis direction), the offset member 160 swings in the width direction (Z-axis direction) in conjunction with the second boom 122. The third boom 123 (more specifically, the third boom 123, the arm 140, and a bucket 180 described later) is substantially translated (offset) while maintaining the posture in the Y-axis direction without being inclined.

  Specifically, a bracket 121c is provided so as to protrude laterally on the left side as viewed from the front of the base end side of the first boom 121. In addition, a bracket 122b is protruded laterally on the left side as viewed from the front of the second boom 122 on the base end side. The offset actuator 170 is interposed between the bracket 121 c of the first boom 121 and the bracket 122 b of the second boom 122.

  In the present embodiment, the attachment 180 connected to the distal end portion 140a of the arm 140 is a bucket provided so as to be swingable around a rotation fulcrum (rotation shaft) P13 along the Z-axis direction. Yes. That is, the bucket 180 is pivotally supported by the tip end portion 140a of the arm 140 on the rotation axis P13. The bucket actuator 190 is interposed between the arm 140 and the bucket 180 to operate the bucket 180. Specifically, the bucket actuator 190 includes a bucket cylinder 190a and a bucket piston 190b. The bucket actuator 190 is provided such that the base end portion 190c of the bucket cylinder 190a is rotatable about a rotation fulcrum (rotation axis) P14 along the Z-axis direction with respect to the arm 140. A tip 190d of the piston 190b is provided to be rotatable about a rotation fulcrum (rotation shaft) P15 along the Z-axis direction with respect to the bucket 180. The bucket actuator 190 rotates the bucket 180 by expanding and contracting by hydraulic pressure. Specifically, an arm bracket 140b is provided on the upper surface of the base end side of the arm 140 so as to protrude upward. The bucket 180 is provided with a link mechanism 181. The bucket actuator 190 is interposed between the arm bracket 140 b of the arm 140 and the link mechanism 181 of the bucket 180. That is, the base end portion of the bucket 180 is pivotally supported on the distal end portion 140a of the arm 140 by the rotation shaft P13. A base end portion 190c of the bucket cylinder 190a is pivotally supported by a rotation shaft P14 on an arm bracket 140b formed on the upper portion of the arm 140. The tip 190d of the bucket piston 190b, one end of the first link member 181a, and one end of the second link member 181b are pivotally supported by the rotation shaft P15. The other end portion of the first link member 181a is pivotally supported by the distal end portion 140a of the arm 140. The other end of the second link member 181b is pivotally supported on the base side of the bucket 180.

  The configuration of the excavator 100 will be described in more detail. The excavator 100 includes a crawler traveling device 102 in addition to the machine main body 101.

  In the excavator 100, a machine main body 101 is disposed on a crawler type traveling device 102 so as to be able to turn left and right. The machine body 101 is supported by a swivel bearing 101b having a swivel frame 101a provided substantially at the center so as to be pivotable about a rotation axis along the Y-axis direction.

  In the crawler type traveling device 102, a crawler belt 102d is wound around the outer periphery of a driving wheel 102a, a driven wheel 102b, and a plurality of wheels 102c,. At one end portion (rear end portion here) of the crawler type traveling device 102 in the X-axis direction (front-rear direction), a soil discharge plate 103 is disposed so as to be rotatable around a rotation axis along the Z-axis direction. ing.

  Above the swivel base frame 101a, a bonnet 106 that houses and covers an engine 104, a fuel tank 105, a battery (not shown), a hydraulic system, and a hydraulic oil tank is disposed. A seat 107 is disposed on the bonnet 106. It is installed.

  An operation column 108 is erected in front of the seat 107 and on the front end of the swivel base frame 101 a, and a step 101 c is provided on the swivel base frame 101 a between the operation column 108 and the seat 107.

  On the operation column 108, operation members 108 a and 108 b for performing excavation work operations are arranged to constitute a control unit 109.

  The excavator 100 according to the present embodiment further includes a hydraulic circuit 230 that supplies hydraulic oil to the boom actuator 130, the arm actuator 150, and the offset actuator 170.

  FIG. 4A is a hydraulic circuit diagram illustrating an example of a hydraulic circuit 230 that supplies hydraulic oil to the boom actuator 130 and the arm actuator 150. FIG. 4B is a hydraulic circuit diagram illustrating an example of a hydraulic circuit 230 that supplies hydraulic oil to the offset actuator 170.

  4A and 4B, the boom actuator 130, the arm actuator 150, and the offset actuator 170 are expanded and contracted by hydraulic oil supplied from hydraulic pumps (hydraulic power sources) 231a, 231b, and 231c.

  The hydraulic circuit 230 includes a boom hydraulic pump 231a, an arm hydraulic pump 231b, an offset hydraulic pump 231c, a pilot pump (hydraulic power source) 232, a boom control valve 233, an arm control valve 234, and an offset. Control valve 290, boom pilot valve (remote control valve) 235, arm pilot valve (remote control valve) 236, offset pilot valve (remote control valve) 291, hydraulic oil tank 237, boom decompressor ( Here, a boom electromagnetic proportional pressure reducing valve 238a) is provided. The pilot pump 232 supplies hydraulic oil (pilot pressure oil) at a pressure lower than the pressures of the boom hydraulic pump 231a, the arm hydraulic pump 231b, and the offset hydraulic pump 231c. Thereby, the boom hydraulic control lever 235i, the arm hydraulic control lever 236i, and the offset hydraulic fluid are supplied from the pilot pump 232 to the boom pilot valve 235, the arm pilot valve 236, and the offset pilot valve 291. The hydraulic operation lever 291i can be easily manually operated.

  The boom hydraulic pump 231 a, the arm hydraulic pump 231 b, the offset hydraulic pump 231 c and the pilot pump 232 are driven by the engine 104.

  As shown in FIG. 4A, the boom hydraulic pump 231a is connected to the hydraulic oil supply port 233c of the boom control valve 233 by a hydraulic line (hydraulic piping) L1a, and supplies the hydraulic oil to the boom control valve 233. . The arm hydraulic pump 231b is connected to the hydraulic oil supply port 234c of the arm control valve 234 by the hydraulic line L1b, and supplies hydraulic oil to the arm control valve 234. As shown in FIG. 4B, the offset hydraulic pump 231c is connected to the hydraulic oil supply port 290c of the offset control valve 290 by the hydraulic line L1c, and supplies the hydraulic oil to the offset control valve 290.

  As shown in FIG. 4A, the pilot pump 232 is connected to the hydraulic oil supply ports 235e and 235f of the boom pilot valve 235 by the pilot hydraulic lines S1a and S2a, and supplies the hydraulic oil to the boom pilot valve 235. The pilot pump 232 is connected to the hydraulic oil supply ports 236e and 236f of the arm pilot valve 236 via the pilot hydraulic lines S1b and S2b, and supplies the hydraulic oil to the arm pilot valve 236. As shown in FIG. 4B, the pilot pump 232 is connected to the hydraulic oil supply ports 291e and 291f of the offset pilot valve 291 via the pilot hydraulic lines S1c and S2c, and supplies the hydraulic oil to the offset pilot valve 291. To do.

[Boom side]
(Boom pilot valve)
The boom pilot valve 235 includes a first boom pilot valve 235a and a second boom pilot valve 235b.

  The first boom pilot valve 235a is connected to the first pilot port 233a of the boom control valve 233 by a pilot hydraulic line S5a connected to the first port 235c, and lifts the boom 120 of the boom hydraulic control lever 235i. The hydraulic fluid from the pilot pump 232 is supplied to the first pilot port 233a of the boom control valve 233 through the pilot hydraulic line S5a by the ascending manual operation.

  The second boom pilot valve 235b is connected to the second pilot port 233b of the boom control valve 233 by a pilot hydraulic line S6a connected to the second port 235d, and lowers the boom 120 of the boom hydraulic control lever 235i. By the downward manipulating operation, hydraulic oil from the pilot pump 232 is supplied to the second pilot port 233b of the boom control valve 233 through the pilot hydraulic line S6a.

  The hydraulic oil supply port 235e of the first boom pilot valve 235a and the hydraulic oil supply port 235f of the second boom pilot valve 235b are connected by a pilot hydraulic line S2a, and the pilot hydraulic line S2a is connected to the pilot pump 232. The connected pilot hydraulic line S1a is connected. Further, the common port 235g of the first boom pilot valve 235a and the common port 235h of the second boom pilot valve 235b are connected by a pilot hydraulic line S3a, and connected to the hydraulic oil tank 237 to the pilot hydraulic line S3a. The pilot hydraulic line S4a is connected. The pilot hydraulic lines S1a to S6a constitute a boom pilot hydraulic circuit.

  When the boom hydraulic control lever 235i is not manually operated, the boom pilot valve 235 communicates with the pilot hydraulic line S5a, the pilot hydraulic line S3a, and the pilot hydraulic line S6a through the pilot pump 232 and the boom control valve 233. Is held in a neutral position to stop the supply of hydraulic oil to When the boom hydraulic control lever 235i is artificially operated to the ascending side, the boom pilot valve 235 is connected to the pilot hydraulic line S2a and the pilot hydraulic line S5a from the neutral position, and the boom pump control valve 233 is connected to the boom control valve 233. The hydraulic oil is supplied to the first pilot port 233a. The boom pilot valve 235 is connected to the pilot hydraulic line S2a and the pilot hydraulic line S6a from the neutral position when the boom hydraulic control lever 235i is manually operated to the lower side, and the boom control valve is connected from the pilot pump 232 to the boom pilot valve 235. The hydraulic oil is supplied to the second pilot port 233b of 233.

  In the boom pilot valve 235, the boom hydraulic control lever 235i is manually operated to the ascending side or the descending side, so that the pilot pressure oil having a pressure corresponding to the operation amount is supplied to the first pilot port of the boom control valve 233. It is configured to be supplied from 233a or the second pilot port 233b.

(Control valve for boom)
The boom control valve 233 includes a pilot operated three-position switching valve provided with a first pilot port 233a and a second pilot port 233b.

  The boom control valve 233 has a discharge port 233d connected to the hydraulic oil tank 237 via a hydraulic line L2a, and discharges the hydraulic oil to the hydraulic oil tank 237 through the hydraulic line L2a. In the boom control valve 233, cylinder side hydraulic oil ports 233e and 233f are connected to the boom raising side oil chamber 131 and the boom lowering side oil chamber 132 of the boom cylinder 130a by hydraulic lines L3a and L4a, respectively. The hydraulic lines L1a to L4a constitute a boom cylinder hydraulic circuit.

  The boom raising side oil chamber 131 of the boom cylinder 130a is an oil chamber on the side where the boom 120 rises when hydraulic oil is supplied. Here, the oil on the side from which the boom piston 130b protrudes by the hydraulic oil. The chamber is a boom raising side oil chamber 131.

  When the hydraulic oil is not supplied from the boom pilot valve 235a, the boom control valve 233 is held at a neutral position where the supply of hydraulic oil from the boom hydraulic pump 231a to the boom cylinder 130a is stopped. In addition, when the hydraulic oil is supplied from the boom pilot valve 235a to the first pilot port 233a, the boom control valve 233 connects the hydraulic line L1a and the hydraulic line L3a, and the hydraulic line L4a and the hydraulic line L2a. Is operated to the boom raising position where the communication is established. On the other hand, in the boom control valve 233, when hydraulic fluid is supplied from the boom pilot valve 235a to the second pilot port 233b, the hydraulic line L1a and the hydraulic line L4a are communicated, and the hydraulic line L3a and the hydraulic line L2a are communicated. Is operated to the boom lowering position where the communication is established.

(Boom electromagnetic proportional pressure reducing valve)
The boom electromagnetic proportional pressure reducing valve 238a is interposed in the pilot hydraulic line S5a, and the boom pilot valve 235a is based on electric power (here, command current value Ia) supplied from the control unit 240 (see FIG. 5A described later). Is adjusted to the first pilot port 233a of the boom control valve 233. This control will be described in detail later.

  In the present embodiment, the command current value Ia supplied to the boom electromagnetic proportional pressure reducing valve 238a is changed to change the valve opening rate of the boom electromagnetic proportional pressure reducing valve 238a (the oil passage opening, that is, the valve in the fully opened state). The ratio of the amount of hydraulic fluid supplied from the pilot pump 232 to the first pilot port 233a of the boom pilot valve 235a is changed (the amount of supply per unit time). By increasing / decreasing the ratio, the change rate of the supply amount of hydraulic oil supplied from the boom hydraulic pump 231a to the boom ascending oil chamber 131 of the boom cylinder 130a via the boom control valve 233 (supply amount per unit time) Increase or decrease.

  Here, the electromagnetic proportional pressure reducing valve 238a for the boom is fully opened when the command current value Ia is a value in the vicinity of 0 [A] or 0 [A], and the valve opening rate decreases as the command current value Ia increases. The characteristic of closing at a predetermined current value or more is shown.

[Arm side and offset side]
Since the arm side and offset side configurations are the same as the boom side configuration, detailed description of the arm side and offset side configurations is omitted here.

  It should be noted that the components of the boom pilot valve 235 correspond to the components of the arm pilot valve 236 and the offset pilot valve 291 with a common reference numeral. Similarly, the constituent elements of the boom control valve 233 correspond to the constituent elements of the arm control valve 234 and the offset control valve 290 with common reference numerals. The pilot hydraulic lines S1a to S6a and the hydraulic lines L1a to L4a are the pilot hydraulic lines S1b to S6b and the hydraulic lines L1b to L4b on the arm side, and the pilot hydraulic lines S1c to S6c and the hydraulic lines L1c to L1c on the offset side. L4c is associated with each.

[Control configuration of control unit]
FIG. 5A is a block diagram schematically showing a system configuration centering on the control unit 240 in the excavator 100. FIG. 5B is a control configuration diagram illustrating details of the control configuration of the processing unit 241 in the control unit 240.

  As shown in FIG. 5A, the excavator 100 according to the present embodiment further includes a boom angle sensor 210 that detects a boom angle α (see FIG. 6 described later) of the boom 120 with respect to the machine body 101, a control unit 240, and the like. It has.

  The boom angle sensor 210 transmits a detection signal αs corresponding to the boom angle α to the control unit 240. As the boom angle sensor 210, a rotation angle sensor such as a rotary encoder or a potentiometer (variable resistor) can be used.

  The excavator 100 according to the present embodiment further includes an offset angle sensor 250 that detects an offset angle γ (see FIG. 7 described later) of the second boom 122 that rotates with respect to the first boom 121 by an offset mechanism. ing.

  The offset angle sensor 250 transmits a detection signal γs corresponding to the offset angle γ to the control unit 240. The offset angle sensor 250 can use a rotation angle sensor such as a rotary encoder or a potentiometer (variable resistor), like the boom angle sensor 210.

  The control unit 240 includes a processing unit 241 including a microcomputer such as a CPU (Central Processing Unit), and a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a data rewritable nonvolatile memory. Part 242.

  The control unit 240 controls the operation of various components by causing the processing unit 241 to load and execute a control program stored in advance in the ROM of the storage unit 242 onto the RAM of the storage unit 242. . The RAM of the storage unit 242 provides a work area for work to the processing unit 241.

  Then, the control unit 240 detects the position (current posture) of the boom 120 based on the boom angle α, and when prohibiting the raising of the boom 120, the control unit 240 supplies the hydraulic oil to the boom raising side oil chamber 131 of the boom cylinder 130a. The supply is stopped. When operating the offset mechanism, the control unit 240 detects the position (current posture) of the boom 120 in consideration of the offset angle γ in addition to the boom angle α.

  Specifically, in the control unit 240, the boom angle sensor 210 and the offset angle sensor 250 are connected to the input system, the boom electromagnetic proportional pressure reducing valve 238a is connected to the output system, and signal input from the input system is performed. Based on the above, the operation control to the output system is repeatedly performed at predetermined intervals (for example, every 10 ms).

  Specifically, as shown in FIG. 5B, the control unit 240 includes a boom angle detection unit M1a, a boom height calculation unit M2a, a set upper limit height setting unit M3, a set boom angle calculation unit M4a, Stop means M5a. In the present embodiment, control unit 240 further includes offset angle detection means M1c.

  FIG. 6 is a schematic side view for explaining the boom angle α, and FIG. 7 is a schematic rear view for explaining the offset angle γ.

(Boom angle detection means)
As shown in FIG. 6, the boom angle detection means M1a detects the boom angle (relative angle) α based on the detection signal αs sent from the boom angle sensor 210. Specifically, the boom angle α can be an angle of a virtual straight line W0 in the boom 120 with respect to a virtual reference straight line Q1 at a reference height position passing through the center of the rotation axis P1.

  Here, the boom angle α is the first boom angle α1 with respect to the virtual reference line Q1 at the reference height position of the virtual straight line W1 (W0) connecting the center of the rotation axis P1 and the center of the rotation axis P8, and the rotation axis. The second boom angle α2 with respect to the virtual reference line Q1 at the reference height position of the virtual line W2 (W0) connecting the center of P1 and the center of the rotation axis P4, and the center of the rotation axis P1 and the center of the rotation axis P13. 3rd boom angle (alpha) 3 with respect to the virtual reference straight line Q1 of the reference | standard height position of the virtual straight line W3 (W0) to connect is included.

(Offset angle detection means)
As shown in FIG. 7, the offset angle detection means M1c detects the offset angle (relative angle) γ based on the detection signal γs sent from the offset angle sensor 250. Specifically, the offset angle γ can be an angle with respect to the virtual reference line Q2 along the Y-axis direction of the reference position passing through the center of the rotation axis P7.

  Here, the offset angle γ is an angle of the reference position of the virtual straight line W6 connecting the center of the rotation axis P7 and the center of the rotation axis P8 with respect to the virtual reference line Q2.

  Next, the boom height calculation means M2a will be described. For convenience of explanation, first, when the offset mechanism is not functioned (here, when the second boom 122 is in a posture parallel to the Y-axis direction, that is, the offset The boom height calculating means M2a at the angle γ = 0 ° will be described, and then the case where the offset mechanism is operated will be described.

(Boom height calculation means)
The boom height calculation means M2a, when not operating the offset mechanism (here, when the offset angle γ is set to 0 °), the virtual reference straight line Q1 of the reference height position at the top of the boom 120 based on the boom angle α. The boom height ha from is calculated. In the present embodiment, the topmost portion of the boom 120 is a part considering contact with an obstacle (for example, a ceiling) above when the boom 120 is rotated in the direction in which the boom 120 is raised assuming that the arm 140 is stopped ( For example, the connected boom 120 and the part which comprises the corner | angular part of the arm 140 are made into object.

  Specifically, as shown in FIG. 6, among the first height h1 of the rotation axis P8, the second height h2 of the rotation axis P4, and the third height h3 of the rotation axis P13, The largest value is taken as the boom height ha (the first height h1 of the rotation axis P8 in the illustrated example).

  The first height h1 of the rotation axis P8 can be calculated based on the first boom angle α1 and the distance of the virtual straight line W1. The second height h2 of the rotation axis P4 can be calculated based on the second boom angle α2 and the distance of the virtual straight line W2. The third height h3 of the rotation axis P13 can be calculated based on the third boom angle α3 and the distance of the virtual straight line W3.

  In order to simplify the description, the first height h1 is the height of the rotation axis P8, the second height h2 is the height of the rotation axis P4, and the third height h3 is the rotation axis P13. However, in reality, a portion at a position higher than each of the rotation axes P8, P4, P13 is a contact target. For this reason, the calculation is performed in consideration of a circumferential range including the contact target portion with the rotation axes P8, P4, P13 as the center. This also applies to the setting upper limit height setting means M3 described later. Hereinafter, the rotation axis P8, the rotation axis P4, and the rotation axis P13 are referred to as a first rotation axis P8, a second rotation axis P4, and a third rotation axis P13, respectively, and the rotation axis P1 and the rotation axis. The axes P7 are referred to as a boom angle reference rotation axis P1 and an offset angle reference rotation axis P7, respectively.

(For offset mechanism)
When the offset mechanism is made to function, the boom height ha is affected, and therefore the offset angle γ is used to calculate the boom height ha. That is, the boom height calculation means M2a subtracts the offset distance Δh shown in FIG. 7 from the calculated boom height ha.

  The offset distance Δh can be calculated as follows, for example. That is, the center of the offset angle reference rotation axis P7, the center of the first rotation axis P8 when the second boom 122 swings in the width direction (Z-axis direction), and the reference from the first rotation axis P8. An offset distance h5 between the intersection Pγ and the center of the offset angle reference rotation axis P7 is calculated in a right triangle connecting the virtual perpendicular Q4 down to the virtual reference straight line Q2 and the intersection Pγ of the virtual reference straight line Q2 at the reference position. Then, an offset distance h5 is obtained from a distance h6 of a virtual straight line W6 connecting the center of the offset angle reference rotation axis P7 and the center of the first rotation axis P8 when the second boom 122 is in a posture parallel to the Y-axis direction. The subtracted value is set as an offset distance Δh.

(Setting upper limit height setting means)
The set upper limit height setting means M3 sets the boom height ha in advance as the set upper limit height h0 (see FIG. 8 described later).

  Specifically, the control unit 240 includes an upper limit height setting mode for setting the set upper limit height. The upper limit height setting mode corresponds to the first target portion corresponding to the first rotation axis P1 and the second rotation axis P2 by the operator performing at least one rotation operation of the boom 120 and the arm 140. An operation member (not shown) for stopping any one of the second target part and the third target part corresponding to the third rotation axis P3 at a position where the upper limit height is to be set and setting the upper limit height in the machine body 101 is provided. When operated by the operator and instructed by the control unit 240, the height of the target portion stopped at the upper limit height (that is, the boom height ha) is stored in the storage unit 242 as the set upper limit height h0. The set upper limit height h0 is held in the storage unit 242 until the next upper limit height setting mode is executed and the upper limit height is set.

(Setting boom angle calculation means)
The set boom angle calculation means M4a calculates a set boom angle α0 of the boom 120 with respect to the machine main body 101 based on the boom height ha and the set upper limit height h0. As shown in FIG. 8, the setting boom angle α0 includes the first maximum allowable angle Δα1 until the first rotation axis P8 reaches the set upper limit height h0, and the second rotation axis P4 has the set upper limit height h0. Can be calculated by using the second maximum allowable angle Δα2 until reaching the third maximum allowable angle Δα3 until the third rotation axis P13 reaches the set upper limit height h0.

  FIG. 8 is a schematic side view for explaining a process of calculating the set boom angle α0 when the boom 120 is rotated in the direction in which the arm 120 is raised assuming that the arm 140 is stopped. 8A shows the first maximum allowable angle Δα1, FIG. 8B shows the second maximum allowable angle Δα2, and FIG. 8C shows the third maximum allowable angle Δα3. Show.

  As shown in FIG. 8A, the first maximum allowable angle Δα1 can be obtained by obtaining the angle formed by the virtual straight line W1a and the virtual straight line W1. The virtual straight line W1a reaches the virtual reference straight line Q3 at the upper limit height position along the X-axis direction of the set upper limit height h0 with the rotation locus K1 centering on the boom angle reference rotation axis P1 of the first rotation axis P8. This is a straight line drawn between the center of the contact position P8a to be touched and the center of the boom angle reference rotation axis P1.

  As shown in FIG. 8B, the second maximum allowable angle Δα2 can be obtained by obtaining the angle formed by the virtual straight line W2a and the virtual straight line W2. The virtual straight line W2a includes the center of the contact position P4a at which the rotation locus K2 about the boom angle reference rotation axis P1 of the second rotation axis P4 reaches the virtual reference straight line Q3 at the upper limit height position, and the boom angle reference rotation. It is a straight line drawn between the center of the dynamic axis P1.

  As shown in FIG. 8C, the third maximum allowable angle Δα3 can be obtained by obtaining an angle formed by the virtual straight line W3a and the virtual straight line W3. The virtual straight line W3a includes the center of the contact position P13a at which the rotation locus K3 about the boom angle reference rotation axis P1 of the third rotation axis P13 reaches the virtual reference straight line Q3 at the upper limit height position, and the boom angle reference rotation. It is a straight line drawn between the center of the dynamic axis P1.

  When the rotation trajectories K1, K2, K3 do not reach the virtual reference straight line Q3 at the upper limit height position, the rotation trajectory K1 of the first rotation axis P8, the rotation trajectory K2 of the second rotation axis P4, and the third The end position of the rotation locus K3 of the rotation axis P13 is a mechanical stop position of the boom actuator 130.

  Then, among the first maximum allowable angle Δα1, the second maximum allowable angle Δα2, and the third maximum allowable angle Δα3, the rotation corresponding to the smallest angle (the second maximum allowable angle Δα2 in the example of FIG. 8) corresponds to the smallest angle. The angle (the angle α02 in the example of FIG. 8) obtained by adding the boom angle α (the second boom angle α2 in the example of FIG. 8) of the dynamic axis (the second rotation axis P4 in the example of FIG. 8) is set as the set boom angle α0. Yes.

(Boom stop means)
The boom stop means M5a is used when the boom angle α reaches the preset boom angle α0 of the boom 120 with respect to the machine main body 101 set in advance by supplying hydraulic oil to the boom ascending oil chamber 131 in the boom cylinder 130a (here, the boom stop means M5a). When 120 rises and reaches the set upper limit height h0), the supply of hydraulic oil to the boom raising side oil chamber 131 is stopped.

  The boom stopping means M5a, when stopping the supply of hydraulic oil to the boom raising side oil chamber 131, has a boom angle α (α2 in the example of FIG. 8) and a set boom angle α0 (α02 in the example of FIG. 8). As the difference value [Delta] [alpha] ([Delta] [alpha] 2 in the example of FIG. 8) decreases, the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 (the amount of decrease per unit time) is increased.

  Specifically, the control unit 240 is configured to receive signals from various sensors such as the boom angle sensor 210 and switches, and based on these input signals, the control configuration of various setting means, calculation means, and the like. To perform processing such as setting and calculation. As shown in FIG. 4A, the control unit 240 controls the boom electromagnetic proportional pressure reducing valve 238a in the pilot hydraulic line S5a connected to the first pilot port 233a of the boom control valve 233 (command current value). Ia) is configured to output.

  Next, an example of stop control for stopping the boom 120 will be described below with reference to FIGS. 5A, 5B, FIGS. 9A to 9C, FIGS. 10 to 15, and the like.

  9A to 9C are schematic control block diagrams illustrating an example of stop control for stopping the boom 120.

  9A and 9B show the components of the input system of the control unit 240. FIG. FIG. 9C shows details of the boom stop means M5a.

  As shown in FIGS. 5B and 9C, the boom stop means M5a has a boom angle deviation calculation means M50a, a boom angle deviation valve opening rate conversion means M51a, and a boom valve opening rate current value conversion means M52a. .

  The boom angle deviation calculating means M50a subtracts the set boom angle α0 calculated by the set boom angle calculating means M4a from the boom angle α detected by the boom angle detecting means M1a, and outputs the obtained value as the boom angle deviation Δα.

  The boom angle deviation valve opening rate conversion means M51a converts the boom angle deviation Δα subtracted by the boom angle deviation calculation means M50a into the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a and outputs the valve opening rate R1.

  FIG. 10 is a characteristic diagram showing an example of the relationship between the boom angle deviation Δα and the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a.

  The characteristic E1 shown in FIG. 10 indicates that the opening ratio R1 of the boom electromagnetic proportional pressure reducing valve 238a decreases as the boom angle deviation Δα output from the boom angle deviation calculating means M50a decreases, and the angle deviation Δα is When the first predetermined value Δαa (> 0) is greater, the valve opening rate R1 increases gently, and when the angular deviation Δα is smaller than the second predetermined value Δαb (<Δαa), the valve opening rate R1 decreases rapidly. It has become. The first predetermined value Δαa and the second predetermined value Δαb can be determined as appropriate based on the characteristic E1.

  A conversion formula or table map showing the characteristic E1 as shown in FIG. 10 is stored in the storage unit 242 in advance, and the conversion formula or table map showing the storage characteristic E1 stored in the storage unit 242 with the boom angle deviation Δα as a parameter is stored. By using, it can convert into the valve opening rate R1 of the electromagnetic proportional pressure reducing valve 238a for booms.

  The boom valve opening rate current value conversion means M52a converts the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a converted by the boom angle deviation valve opening rate conversion means M51a to the boom command current value Ia of the boom electromagnetic proportional pressure reducing valve 238a. The boom command current value Ia is output after conversion.

  FIG. 11 is a characteristic diagram showing an example of the relationship between the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a and the boom command current value Ia.

  The characteristic E2 shown in FIG. 11 indicates that the boom command current value Ia decreases as the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a increases, and the valve opening rate R1 is a predetermined value Ra1 (0 <Ra1 < When the value is larger than 1), the command current value Ia has a characteristic of rapidly decreasing. The predetermined value Ra1 can be determined as appropriate based on the characteristic E2.

  A conversion equation or table map indicating the characteristic E2 as shown in FIG. 11 is stored in the storage unit 242 in advance, and the characteristic E2 stored in the storage unit 242 using the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a as a parameter is stored. By using the conversion formula or table map shown, the boom command current value Ia can be converted.

(Correction by angular velocity)
In the present embodiment, as shown in FIGS. 5B and 9A, the control unit 240 further includes a boom angular velocity calculation means M6a.

  The boom angular velocity calculating means M6a calculates the boom angular velocity ωa based on the boom angle α and outputs the angular velocity ωa.

  Specifically, the boom angular velocity calculation unit M6a stores the boom angle α detected by the boom angle detection unit M1a by the boom angle sensor 210 in the storage unit 242, and then determines the boom angular velocity based on the difference from the detected boom angle α and the elapsed time. Calculate ωa.

  By the way, if the boom angular velocity ωa is large, the inertial force with respect to the boom 120 tends to increase.

  From this point of view, as shown in FIGS. 5B and 9C, the boom stop means M5a further includes a boom supply amount adjustment means M53a.

  The boom supply amount adjusting unit M53a increases the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 as the boom angular velocity ωa calculated by the boom angular velocity calculating unit M6a increases.

  Specifically, the boom supply amount adjustment means M53a includes a boom angle deviation opening correction ratio conversion means M531a, a boom angular speed opening correction ratio conversion means M532a, a boom opening correction ratio integration means M533a, and a boom opening correction ratio subtraction. Means M534a.

  The boom angle deviation opening correction ratio conversion means M531a converts the boom angle deviation Δα output from the boom angle deviation calculation means M50a into a boom first valve opening rate correction ratio D1a and outputs a correction ratio D1a.

  FIG. 12 is a characteristic diagram showing an example of the relationship between the boom angle deviation Δα and the boom first valve opening rate correction ratio D1a.

  The characteristic E3 shown in FIG. 12 indicates that the boom first valve opening rate correction ratio D1a increases as the boom angle deviation Δα output from the boom angle deviation calculating means M50a decreases, and the angle deviation Δα is a first predetermined value. When the value Δαc (0 ° <Δαc <90 °) is greater, the correction ratio D1a is a value near 0 or 0, and when the angle deviation Δα is smaller than the second predetermined value Δαd (<Δαc), the correction ratio D1a is near 1. Or a value of 1. The first predetermined value Δαc and the second predetermined value Δαd can be determined as appropriate based on the characteristic E3.

  A conversion formula or table map indicating the characteristic E3 as shown in FIG. 12 is stored in the storage unit 242 in advance, and the conversion formula or table map indicating the characteristic E3 stored in the storage unit 242 using the boom angle deviation Δα as a parameter is used. Thus, the boom first valve opening rate correction ratio D1a can be converted.

  The boom angular speed opening correction ratio conversion means M532a converts the boom angular speed ωa output from the boom angular speed calculation means M6a into the boom second valve opening rate correction ratio D2a and outputs the correction ratio D2a.

  FIG. 13 is a characteristic diagram showing an example of the relationship between the boom angular velocity ωa and the boom second valve opening rate correction ratio D2a.

  The characteristic E4 shown in FIG. 13 indicates that the boom second valve opening rate correction ratio D2a decreases as the boom angular velocity ωa output from the boom angular velocity calculating means M6a decreases, and the angular velocity ωa is a predetermined value ω1 (> 0). ) Is smaller, the correction ratio D2a has a characteristic of rapidly decreasing. The predetermined value ω1 can be determined as appropriate based on the characteristic E4.

  A conversion formula or table map showing the characteristic E4 as shown in FIG. 13 is stored in the storage unit 242 in advance, and the conversion formula or table map showing the characteristic E4 stored in the storage unit 242 with the boom angular velocity ωa as a parameter is used. Thus, the second valve opening rate correction ratio D2a can be converted.

  The boom opening correction ratio integration means M533a includes a boom first valve opening rate correction ratio D1a output from the boom angle deviation opening correction ratio conversion means M531a and a boom first speed output ratio correction means conversion means M532a. 2 is multiplied by the valve opening rate correction ratio D2a, and the resulting boom valve opening rate correction ratio D3a is output.

  Then, the boom opening correction ratio subtracting means M534a is supplied from the boom opening correction ratio integrating means M533a to the valve opening ratio R1 of the boom electromagnetic proportional pressure reducing valve 238a output from the boom angle deviation valve opening rate conversion means M51a. The output boom opening rate correction ratio D3a is subtracted (or a negative value is added).

  Thus, when the boom angle α is close to the set boom angle α0, the correction value is set according to the boom angular speed ωa, while when the boom angle α is away from the set boom angle α0, the correction value based on the boom angular speed ωa is invalidated. can do.

(Correction by boom link ratio)
In the rotation mechanism of the boom 120, the rotation amount of the boom 120 with respect to the movement amount of the boom piston 130b does not always indicate a fixed relationship. In the present embodiment, the turning mechanism of the boom 120 is a turning mechanism that increases the angular velocity ωa of the boom 120 when the boom angle α is close to 90 °.

  From this point of view, in the present embodiment, the boom stop means M5a further reduces the amount of hydraulic oil supplied to the boom raising side oil chamber 131 as the boom angle α approaches 90 °.

  Specifically, the boom stop means M5a further includes a boom link ratio correction means M54a.

  The boom link ratio correction means M54a converts the boom angle α detected by the boom angle detection means M1a into a boom link ratio correction ratio D4a (see FIG. 14), and the converted boom link ratio correction ratio D4a and boom angle deviation calculation means. The boom angle deviation Δα output from the M50a is multiplied and the resulting boom angle deviation Δα is output.

  FIG. 14 is a characteristic diagram showing an example of the relationship between the boom angle α and the boom link ratio correction factor D4a.

  The characteristic E5 shown in FIG. 14 indicates that the boom link ratio correction factor D4a increases as the boom angle α detected by the boom angle detection means M1a decreases, and the angle α is greater than or equal to 0 ° and a predetermined value αa (0 <αa When the angle is smaller than <90 °, the correction rate D4a is a value close to 1 or 1, and when the angle α is not less than the predetermined value αa and not more than 90 °, the correction rate D4a rapidly decreases. The predetermined value αa can be determined as appropriate based on the characteristic E5.

  A conversion formula or table map indicating the characteristic E5 as shown in FIG. 14 is stored in the storage unit 242 in advance, and the conversion formula or table map indicating the characteristic E5 stored in the storage unit 242 with the boom angle α as a parameter is used. Thus, the boom link ratio correction rate D4a can be converted.

(Correction by engine speed)
In the present embodiment, excavator 100 further includes an engine speed sensor 260 (see FIGS. 5A and 9B) that detects engine speed N of engine 104. An engine speed sensor 260 is connected to the input system of the control unit 240.

  The engine speed sensor 260 transmits a detection signal Ns corresponding to the engine speed N to the control unit 240. As the engine speed sensor 260, a generator such as an alternator can be used.

  Specifically, the control unit 240 further includes engine speed detection means M7 that detects the engine speed N per unit time (see FIGS. 5B and 9B).

  Specifically, the engine speed detection means M7 detects the signal output Ns from the engine speed sensor 260 (for example, counts the power generation pulse voltage) and converts it into the engine speed N.

  By the way, when the engine speed N is large, the inertial force with respect to the boom 120 and the arm 140 tends to increase.

  From this point of view, in the present embodiment, the boom stop means M5a further includes boom engine speed correction means M55a. The boom engine speed correcting means M55a increases the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 as the engine speed N converted by the engine speed detecting means M7 increases.

  Specifically, the boom engine speed correcting means M55a converts the engine speed N converted by the engine speed detecting means M7 into a boom engine speed correction factor D5a (0 <D5a <1), and the converted boom speed. The engine rotation speed correction rate D5a and the boom command current value Ia output from the boom valve opening rate current value conversion means M52a are multiplied to output the obtained boom command current value Ia.

  FIG. 15 is a characteristic diagram showing an example of the relationship between the engine speed N and the boom engine speed correction factor D5a.

  The characteristic E6 shown in FIG. 15 indicates that the boom engine speed correction rate D5a decreases as the engine speed N converted by the engine speed detecting means M7 decreases, and the engine speed N is less than the predetermined value Na. When it is small, the correction rate D5a becomes a value near the predetermined correction rate D5a1 (0 <D5a1 <1) or the predetermined correction rate D5a1, and when the engine speed N is equal to or higher than the predetermined value Na (> 0), the correction rate D5a Has a characteristic of rising in a curve. The predetermined value Na and the predetermined correction factor D5a1 can be determined as appropriate based on the characteristic E6.

  A conversion formula or table map showing the characteristic E6 as shown in FIG. 15 is stored in the storage unit 242 in advance, and the conversion formula or table map showing the characteristic E6 stored in the storage unit 242 using the engine speed N as a parameter is used. Thus, the engine speed can be converted to the boom engine speed correction rate D5a.

(Correction by hydraulic oil temperature)
In the present embodiment, excavator 100 further includes a temperature sensor 270 (see FIGS. 5A and 9B) that detects a hydraulic oil temperature T of hydraulic oil (for example, hydraulic oil in hydraulic oil tank 237). A temperature sensor 270 is connected to the input system of the control unit 240.

  The temperature sensor 270 transmits a detection signal Ts corresponding to the hydraulic oil temperature T to the control unit 240. As the temperature sensor 270, a temperature sensitive sensor such as a thermocouple or a thermistor can be used.

  Specifically, the control unit 240 further includes hydraulic oil temperature detection means M8 that detects the hydraulic oil temperature T (see FIGS. 5B and 9B).

  Specifically, the hydraulic oil temperature detection means M8 converts the signal output Ts from the temperature sensor 270 into the hydraulic oil temperature T.

  By the way, when the hydraulic oil temperature T is low, the fluidity of the hydraulic oil is lowered, so that the inertia force with respect to the boom 120 tends to be small.

  From this point of view, in the present embodiment, the boom stop means M5a further includes boom hydraulic oil temperature correction means M56a. The boom hydraulic oil temperature correction means M56a reduces the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 as the hydraulic oil temperature T converted by the hydraulic oil temperature detection means M8 decreases.

  Specifically, the boom hydraulic oil temperature correction means M56a converts the hydraulic oil temperature T converted by the hydraulic oil temperature detection means M8 into a boom hydraulic oil temperature correction factor D6a (0 <D6a <1), and converts the boom hydraulic oil temperature T. The hydraulic oil temperature correction factor D6a and the boom command current value Ia output from the boom valve opening rate current value conversion means M52a are multiplied to output the obtained boom command current value Ia.

  The relationship between the hydraulic oil temperature T and the boom hydraulic oil temperature correction factor D6a is not shown.

(Compensation by hydraulic pressure)
In the present embodiment, the excavator 100 further includes a boom hydraulic pressure sensor 280a (see FIGS. 5A and 9B) that detects the boom hydraulic pressure Va of the boom raising side oil chamber 131. A boom hydraulic pressure sensor 280a is connected to the input system of the controller 240. For example, the boom hydraulic pressure sensor 280a can be provided in the hydraulic line L3a (see FIG. 4A).

  The boom hydraulic pressure sensor 280a transmits a detection signal Vas corresponding to the boom hydraulic pressure Va to the control unit 240. As the boom hydraulic pressure sensor 280a, a piezoelectric sensor incorporating a piezoelectric element can be used.

  Specifically, the control unit 240 further includes boom hydraulic pressure detection means M9a that detects the boom hydraulic pressure Va (see FIGS. 5B and 9B).

  Specifically, the boom hydraulic pressure detection means M9a converts the signal output Vas from the boom hydraulic pressure sensor 280a into the boom hydraulic pressure Va.

  By the way, if the boom hydraulic pressure Va is large, it can be considered that the boom 120 is loaded.

  From this point of view, in the present embodiment, the boom stop means M5a further includes boom hydraulic pressure correction means M57a. The boom hydraulic pressure correction means M57a decreases the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 as the boom hydraulic pressure Va converted by the boom hydraulic pressure detection means M9a increases.

  Specifically, the boom hydraulic pressure correction means M57a converts the boom hydraulic pressure Va converted by the boom hydraulic pressure detection means M9a into a boom hydraulic pressure correction ratio D7a (0 <D7a <1), and converts the converted boom hydraulic pressure correction ratio D7a to the boom hydraulic pressure correction ratio D7a. The boom command current value Ia output from the valve opening rate current value conversion means M52a is multiplied and the resulting boom command current value Ia is output.

  The relationship between the boom hydraulic pressure Va and the boom hydraulic correction factor D7a is not shown.

(Correction for crane mode)
In the present embodiment, the excavator 100 has a crane mode used as a crane. Specifically, the excavator 100 enters the crane mode when an operation member (not shown) for setting the crane mode of the machine main body 101 is operated by an operator and the control unit 240 is instructed.

  The control unit 240 includes crane mode execution means M10 that specifies a function for the crane mode (see FIG. 5B). The crane mode refers to a mode in which predetermined functions (for example, turning speed and traveling speed) are restricted in order to perform crane work, and is a mode corresponding to so-called crane specifications. That is, in the crane mode, the operation is limited compared to during excavation work.

  In the present embodiment, the control unit 240 further includes a total discharge amount suppression unit M11 from the viewpoint that the operation of the crane mode execution unit M10 is restricted in the crane mode as compared to during excavation work (see FIG. 5B). . The total discharge amount suppression unit M11 suppresses the total discharge amount of the pilot pump 232 during the crane mode by the crane mode execution unit M10.

  The hydraulic circuit 230 shown in FIGS. 4A and 4B includes a total amount regulating pressure reducing device (here, a total amount regulating electromagnetic proportional pressure reducing valve 239). The total amount regulating electromagnetic proportional pressure reducing valve 239 is provided in the pilot hydraulic lines S1a, S1b, S1c. A total amount description electromagnetic proportional pressure reducing valve 239 is connected to the output system of the control unit 240 (see FIG. 5A), and the discharge total amount suppression means M11 is commanded from the control unit 240 during excavation work in the crane mode. A command current value Id larger than that is output to the total amount description electromagnetic proportional pressure reducing valve 239.

(Correction for upper limit of piston protrusion)
In the boom actuator 130, when the boom piston 130b reaches the mechanical upper limit (here, the upper limit protruding by the boom piston 130b), the boom actuator 130 inevitably stops.

  From this point of view, in this embodiment, the boom upper limit angle with respect to the machine main body 101 (here, the virtual reference line Q1 at the reference height position) up to the mechanical operation limit (here, the upper limit of protrusion) when the boom 120 is raised. αmax (see FIG. 16) is stored in the storage unit 242 in advance.

  FIG. 16 is a schematic side view for explaining the correction of the upper limit of protrusion of the piston 130b in the boom actuator 130. FIG. FIG. 16 shows a difference value Δαmax between the boom angle α and the boom upper limit angle αmax.

  As shown in FIG. 5B, the boom stop means M5a further includes a boom upper limit correction means M58a. The boom upper limit correcting means M58a is configured to raise the boom when the difference value Δαmax between the boom upper limit boom angle α (see the imaginary line in the figure) and the boom upper limit angle αmax (see the solid line in the figure) is equal to or less than a predetermined first angle. The amount of hydraulic oil supplied to the oil chamber 131 is reduced.

  Specifically, the boom upper limit correction means M58a is configured to output the boom command output from the boom opening rate current value conversion means M52a when the difference value Δαmax between the boom angle α and the boom upper limit angle αmax is equal to or smaller than a predetermined first angle. The current value Ia is multiplied by a coefficient greater than 1, and the obtained boom command current value Ia is output to the boom electromagnetic proportional pressure reducing valve 238a.

(Correction at the initial stage of boom drive)
In the boom 120, it is easy to accelerate rapidly in the initial stage of driving (the initial stage of rotation), and the inertial force with respect to the boom 120 tends to increase accordingly.

  From this point of view, in this embodiment, as shown in FIGS. 5B and 9C, the boom stop means M5a further includes boom drive initial correction means M59a. The boom drive initial correcting means M59a is the boom raising side at the initial stage of drive (specifically, when the boom angular velocity ωa is 0 [rad / s] (or a value greater than 0 [rad / s] and less than or equal to a predetermined value)). The amount of hydraulic oil supplied to the oil chamber 131 is reduced.

  Specifically, the boom drive initial correction means M59a outputs from the boom opening correction ratio subtraction means M534a when the boom angular velocity ωa is 0 [rad / s] (or a value greater than 0 [rad / s] and not more than a predetermined value). On the other hand, the valve opening rate R1 of the boom electromagnetic proportional pressure reducing valve 238a is multiplied by a coefficient greater than 0 and less than 1, and the obtained valve opening rate R1 is output to the boom valve opening rate current value conversion means M52a. When the boom angular velocity ωa is other than 0 [rad / s] (or a value greater than 0 [rad / s] and less than or equal to a predetermined value), the boom electromagnetic proportional pressure reducing valve 238a output from the boom opening correction ratio subtracting means M534a. The valve opening rate R1 is output as it is to the boom opening rate current value conversion means M52a.

  According to the working machine 100 described above, the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 is increased as the difference value Δα between the boom angle α and the set boom angle α0 decreases. As the angle α approaches the set boom angle α0, the amount of hydraulic oil supplied to the boom raising side oil chamber 131 can be reduced, and the boom 120 can be gently stopped up to the set boom angle α0. . In addition, in the range where there is a margin to the boom angle α up to the set boom angle α0, it is possible to suppress the deceleration of the rising speed of the boom 120, thereby preventing a reduction in work efficiency.

  Further, in the present embodiment, the boom angular velocity ωa is calculated based on the boom angle α, and as the boom angular velocity ωa increases, the rate of decrease in the amount of hydraulic oil supplied to the boom ascending oil chamber 131 is increased. The boom 120 can be decelerated in accordance with the boom raising speed ωa when raising the 120, and thus the boom 120 can be gently stopped up to the set boom angle α0.

  In the present embodiment, the engine speed N of the engine 104 is detected, and as the engine speed N increases, the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber 131 is increased. Thus, even when the engine speed N is large, the boom 120 can be gently and reliably stopped up to the set boom angle α0.

  In the present embodiment, the hydraulic oil temperature T of the hydraulic oil is detected, and the lower the hydraulic oil temperature T, the smaller the rate of decrease of the hydraulic oil supply amount to the boom raising side oil chamber 131 is reduced. When the oil temperature T is lower than the specified temperature or lower than the specified temperature, it is possible to suppress the amount of reduction of the working oil to the boom raising side oil chamber 131, thereby preventing the work efficiency from being lowered.

  Further, in the present embodiment, the boom hydraulic pressure Va of the boom raising side oil chamber 131 is detected, and as the boom hydraulic pressure Va is higher, the reduction rate of the amount of hydraulic oil supplied to the boom raising side oil chamber 131 is reduced. Even when the boom raising load when raising the boom 120 is large, the boom 120 can be gently and reliably stopped up to the set boom angle α0.

  Moreover, in this Embodiment, the climbing speed of the boom 120 in crane mode can be suppressed by suppressing the discharge total amount of the hydraulic pump 232 at the time of crane mode.

  Further, in the present embodiment, when the difference value Δαmax between the boom angle α and the boom upper limit angle αmax up to the operation limit at which the boom 120 is raised is equal to or smaller than the predetermined first angle αa, the boom raising side oil chamber 131 is returned. By reducing the amount of hydraulic oil supplied, the piston 130b can be gently stopped at the stroke end in the boom cylinder 130a.

  In the present embodiment, the initial drive of the boom actuator 130 can be performed gently by suppressing the amount of hydraulic oil supplied to the boom raising side oil chamber 131 at the initial stage of drive.

  In the present embodiment, the boom electromagnetic proportional pressure reducing valve 238a is provided in the pilot hydraulic line S5a, but may be provided in the hydraulic line L1a and / or the hydraulic line L4a. Further, the total amount regulating electromagnetic proportional pressure reducing valve 239 is provided in the pilot hydraulic lines S1a to S1c, but may be provided in the hydraulic lines L1a to L1c.

  In FIG. 5B, the respective means are described separately for convenience of explanation, but the control unit 240 executes the respective means described above by operating based on the respective programs described above. Therefore, in each of the above-described means and steps, there may be cases where at least two are operated in combination.

DESCRIPTION OF SYMBOLS 100 Excavator 101 Machine main body 104 Engine 120 Boom 121 1st boom 122 2nd boom 123 3rd boom 130 Boom actuator 130a Boom cylinder 130b Boom piston 131 Boom raising side oil chamber 140 Arm 150 Arm actuator 150a Arm cylinder 150b Arm piston 151 Arm raising side oil chamber 170 Offset actuator 170a Offset cylinder 170b Offset piston 171 Offset raising side oil chamber 210 Boom angle sensor 230 Hydraulic circuit 231a Boom hydraulic pump 231b Arm hydraulic pump 231c Offset hydraulic pump 232 Pilot pump 233 Boom control valve 234 Boom control valve 235 Pilot valve 236 arm pilot valve 238a electromagnetic proportional pressure reducing valve 239 for boom total control electromagnetic proportional valve 240 control unit 241 processing unit 242 storage unit 250 offset angle sensor 260 engine speed sensor 270 temperature sensor 280a boom hydraulic pressure sensor 290 offset Control valve 291 Offset pilot valve M1a Boom angle detection means M1c Offset angle detection means M2a Boom height calculation means M3 Set upper limit height setting means M4a Set boom angle calculation means M5a Boom stop means M50a Boom angle deviation calculation means M51a Boom angle Deviation valve opening rate conversion means M52a Boom valve opening rate current value conversion means M53a Boom supply amount adjustment means M531a Boom angle deviation opening correction ratio conversion means M532a Boom angular velocity opening compensation Direct ratio conversion means M533a Boom opening correction ratio integration means M534a Boom opening correction ratio subtraction means M54a Boom link ratio correction means M6a Boom angular speed calculation means M7 Engine speed detection means M8 Hydraulic oil temperature detection means M9a Boom oil pressure detection means M10 Crane mode Execution means N Engine speed T Hydraulic oil temperature Q1 Virtual reference straight line Q2 at reference height position Virtual reference straight line Q3 at reference position Virtual reference straight line ha at upper limit height ha Boom height h0 Set upper limit height α Boom angle γ Offset angle α0 Set boom angle ωa Boom angular velocity Δα Difference value between boom angle and set boom angle

Claims (7)

The boom angle of the boom relative to the machine main body is detected by detecting the boom angle of the boom relative to the machine body, and the boom is raised by supplying hydraulic oil to the boom raising side oil chamber in the boom cylinder. An excavator for stopping the supply of hydraulic oil to the boom raising side oil chamber,
An excavator characterized in that the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber increases as the difference between the boom angle and the set boom angle decreases. The excavator according to claim 1,
An excavator characterized in that a boom angular velocity is calculated based on the boom angle, and a decreasing rate of the amount of hydraulic oil supplied to the boom raising side oil chamber is increased as the boom angular velocity is faster. The excavator according to claim 1 or 2,
An excavator characterized in that an engine speed of an engine is detected, and a reduction ratio of the amount of hydraulic oil supplied to the boom raising side oil chamber is increased as the engine speed increases. . The excavator according to any one of claims 1 to 3,
An excavator comprising a configuration in which a hydraulic oil temperature of hydraulic oil is detected, and the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber is reduced as the hydraulic oil temperature is lower. The excavator according to any one of claims 1 to 4, wherein
An excavator characterized by detecting a boom hydraulic pressure in the boom raising side oil chamber and adding a configuration in which the rate of decrease in the amount of hydraulic oil supplied to the boom raising side oil chamber decreases as the boom hydraulic pressure increases. . An excavator according to any one of claims 1 to 5,
Crane mode execution means for specifying the function for the crane mode used as a crane is provided,
An excavator characterized by adding a configuration for suppressing the total discharge amount of a hydraulic pump that circulates hydraulic oil to a hydraulic circuit during the crane mode by the crane mode execution means. The excavator according to any one of claims 1 to 6,
An excavator characterized in that a configuration for suppressing the amount of hydraulic oil supplied to the boom raising side oil chamber at the initial stage of driving is added.

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