JP2007170048A - Cabin lifting device and driving method of cabin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cabin lifting device which reduces vibration transmitted from a traveling body or an upper body in a cabin at an upper stop position, and also to provide a driving method of the cabin. <P>SOLUTION: The cabin lifting device is provided with a 3 position switching valve 16 for adjusting the supply and discharge of operating oil to a hydraulic cylinder 6 and a controller 8 for controlling the extending/contracting action of the rod 11 of the hydraulic cylinder 6 by operating the 3 position switching valve 16. The controller 8 is constituted to stop the cabin 3 in a range below the upper stop position which is set on the side before an upper limit position where the rod 11 of the hydraulic cylinder 6 reaches an stroke end. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cabin elevating device that elevates and lowers a cabin according to a work situation or the like in a working machine such as a hydraulic excavator, a crusher, or a crane.

  Conventionally, the working machine includes a self-propelled traveling body, an upper body mounted on the traveling body, a cabin provided on the upper body, and a cabin lifting / lowering that raises and lowers the cabin relative to the upper body. What is provided with the apparatus is known.

The cabin lifting device includes a parallel link mechanism provided between the upper body and the cabin, and a hydraulic cylinder that operates the parallel link mechanism, and the link of the parallel link mechanism is caused by the expansion and contraction of the rod of the hydraulic cylinder. A cabin elevating device that elevates and lowers the cabin by rotating the upper body relative to the upper body is known (for example, Patent Document 1).
JP 2003-184127 A

  However, the conventional cabin elevating device is configured to drive the cabin to a preset upper stop position by driving the rod of the hydraulic cylinder to one of the stroke ends. In this case, not only the rod is stopped in the hydraulic cylinder and cannot be extended or shortened physically, but the hydraulic oil in the hydraulic cylinder is pressurized by further supplying hydraulic oil from this stop state. Thus, the rod can hardly expand and contract even when external force is applied.

  Therefore, in the conventional cabin elevating device, when the operation is performed with the cabin set to the upper stop position, vibrations generated in the traveling body and the upper body during the operation, that is, vibrations applied to the hydraulic cylinder are almost directly transmitted to the cabin. There was a risk of discomfort to the passengers.

  The present invention has been made in view of the above problems, and provides a cabin elevating device and a cabin driving method capable of mitigating vibrations transmitted from a traveling body or an upper body with respect to a cabin set as an upper stop position. The purpose is that.

  In order to solve the above-described problems, the present invention relates to a cabin lifting / lowering having a hydraulic cylinder that lifts / lowers a cabin held up and down by an upper body mounted on a self-propelled traveling body of a work machine. A supply / discharge valve that adjusts the supply and discharge of hydraulic oil to and from the hydraulic cylinder, and a control means that controls the expansion and contraction of the rod of the hydraulic cylinder by operating the supply / discharge valve. The control means stops the cabin in a range below the upper stop position set in front of the upper limit position when the rod of the hydraulic cylinder reaches the stroke end. provide.

  According to the present invention, the cabin is configured to stop in the range below the upper stop position set on the near side of the upper limit position when the rod of the hydraulic cylinder reaches the stroke end. It is possible to prevent the cabin from stopping at the upper limit position where the stroke reaches the stroke end.

  In this way, the rod can be displaced in a telescopic direction to some extent, unlike the situation where the rod is pressed against the stroke end at a high pressure by being stopped at a position closer to the stroke end than the stroke end. Situation.

  Therefore, even when the work is performed with the cabin in the upper stop position and vibrations generated in the traveling body and the upper body are added to the rod during the work, the rod operates in the cylinder in response to this vibration. By expanding and contracting while compressing oil, the hydraulic cylinder acts as a damper and can effectively absorb the vibration.

  Specifically, the control means detects the cabin by the position detection means capable of detecting that the cabin has reached a specific position below the upper stop position when stopping the cabin at the upper stop position. By stopping the expansion / contraction operation of the rod with reference to the point in time, the cabin can be configured to stop at the upper stop position before the cabin reaches the upper limit position.

  According to this configuration, since the cabin can be stopped in the process of ascending by stopping the cabin before reaching the upper limit position, the cabin is once driven to the upper limit position and then returned to the upper stop position. The time for raising the cabin can be shortened.

  Further, when the control means stops the cabin at the upper stop position, it is detected that the cabin has reached the upper limit position by position detection means for detecting whether the cabin has reached the upper limit position. After that, the cabin can be configured to be lowered from the upper limit position by a predetermined amount.

  According to this configuration, since the cabin is lowered by a predetermined amount after the position detection unit detects that the cabin has reached the upper limit position, there is some error in the cabin position detection by the position detection unit. Even in this case, the cabin can be reliably stopped at the upper stop position or at a position lower than the upper stop position.

  That is, in the above configuration, even if the actual position of the cabin detected as having reached the upper limit position by the position detection means is not the upper limit position (when an error has occurred in the position detection means), Since the cabin is further lowered from the position by a predetermined amount, the cabin can be stopped at least at a position below the upper stop position regardless of the position at the time of position detection. In other words, it is possible to reliably avoid the rod from stopping at the stroke end.

  The “predetermined amount” refers to the amount of movement that reaches the upper stop position when the cabin located at the upper limit position is lowered. That is, even when the actual position of the cabin at the time of detection by the position detection means is below the upper limit position, the cabin can be stopped below the upper stop position by being lowered by the predetermined amount. .

  Furthermore, the control means can be configured to lower the cabin by a predetermined amount when an ascending command operation of an operation unit that receives a command operation for raising and lowering the cabin from an occupant is released.

  According to this configuration, the cabin can be lowered by a predetermined amount in response to the release of the cabin ascending command operation by the operation unit regardless of the position of the cabin at the time of the operation release.

  Therefore, even when the cabin has already reached the upper limit position during the ascending command operation by the operating unit, the cabin is lowered from the upper limit position by a predetermined amount by subsequently releasing the operation of the operating unit. Even without using a detection means for detecting the position of the cabin, the cabin can be reliably stopped at the upper stop position or the lower position.

  The “predetermined amount” refers to the amount of movement that reaches the upper stop position when the cabin located at the upper limit position is lowered. That is, even when the cabin position at the time when the operation of the operation unit is released is below the upper limit position, the cabin can be stopped below the upper stop position by being lowered by the predetermined amount.

  Further, the control means has a lower stop position set on the near side of the lower limit position when the rod of the hydraulic cylinder reaches the stroke end opposite to the stroke end corresponding to the upper limit position. It can be configured to stop in the above range.

  According to this configuration, the cabin is located above the lower stop position set on the near side of the lower limit position when the rod of the hydraulic cylinder reaches the stroke end opposite to the stroke end corresponding to the upper limit position. Therefore, it is possible to prevent the cabin from stopping at the lower limit position where the rod has reached the stroke end.

  In this way, the rod can be displaced in a telescopic direction to some extent, unlike the situation where the rod is pressed against the stroke end at a high pressure by being stopped at a position closer to the stroke end than the stroke end. Situation.

  Therefore, even when the work is performed with the cabin in the lower stop position and vibrations generated in the traveling body and the upper body during the work are applied to the rod, the rod is moved into the cylinder in response to the vibration. By expanding and contracting while compressing the hydraulic oil, the hydraulic cylinder acts as a damper and can effectively absorb the vibration.

  The present invention also relates to a method for raising a cabin that is held up and down by an upper body mounted on a self-propelled traveling body of a work machine, the hydraulic pressure for raising and lowering the cabin. Supplying and discharging the hydraulic oil into one chamber of the cylinder and discharging the hydraulic oil from the other chamber to raise the cabin; and stopping the supply and discharge of the hydraulic oil, And a stopping step of stopping in a lower range from an upper stop position set on the near side of the upper limit position when the rod of the hydraulic cylinder reaches the stroke end. .

  According to this method, in the stop step, the cabin is stopped in a range below the upper stop position set on the near side of the upper limit position when the rod of the hydraulic cylinder reaches the stroke end. It is possible to prevent the cabin from stopping at the upper limit position that has reached the end.

  In this way, the rod can be displaced in a telescopic direction to some extent, unlike the situation where the rod is pressed against the stroke end at a high pressure by being stopped at a position closer to the stroke end than the stroke end. Situation.

  Therefore, even when the work is performed with the cabin in the upper stop position and vibrations generated in the traveling body and the upper body are added to the rod during the work, the rod operates in the cylinder in response to this vibration. By expanding and contracting while compressing oil, the hydraulic cylinder acts as a damper and can effectively absorb the vibration.

  In the drive method, in the stop step, it is confirmed whether or not the cabin has reached a specific position below the upper stop position, and the supply and discharge of the hydraulic oil are performed based on the confirmed time point. It is preferable to stop the rising of the cabin at a stage before the cabin reaches the upper limit position by stopping.

  According to this method, the cabin can be stopped in the process of ascending by stopping the cabin in the stage before reaching the upper limit position, so that the cabin is once driven to the upper limit position and then returned to the upper stop position. The time for raising the cabin can be shortened.

  Further, in the driving method, in the stopping step, it is confirmed whether or not a cabin has reached the upper limit position, and in the stopping step, it is confirmed that the cabin has reached the upper limit position. It is preferable to further include a reverse driving step of lowering the cabin by a predetermined amount from the upper limit position by supplying the hydraulic oil to the tank and discharging the hydraulic oil in the one chamber.

  According to this method, since it is confirmed that the cabin has reached the upper limit position in the stopping step, the cabin is lowered in the reverse driving step, so there is some error in checking the cabin position. Even in this case, the cabin can be reliably stopped at the upper stop position or at a position lower than the upper stop position.

  That is, in the above method, even when the actual position of the cabin that has been confirmed to have reached the upper limit position is not the upper limit position (when there is an error in position confirmation), the cabin is moved from the current position. Further, since the vehicle is lowered by a predetermined amount, the cabin can be stopped at least at a position below the upper stop position regardless of the position at the time of the position confirmation. In other words, it is possible to reliably avoid the rod from stopping at the stroke end.

  The “predetermined amount” refers to the amount of movement that reaches the upper stop position when the cabin located at the upper limit position is lowered. That is, even when the actual position of the cabin at the time of position confirmation is below the upper limit position, the cabin can be stopped below the upper stop position by being lowered by the predetermined amount.

  ADVANTAGE OF THE INVENTION According to this invention, about the cabin made into the upper side stop position, the vibration transmitted from a traveling body or an upper body can be relieved.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view schematically showing a cabin lifting / lowering device according to an embodiment of the present invention, showing a state where the cabin is in the raised position. FIG. 2 is a circuit diagram showing a hydraulic and electrical configuration of the lifting device of FIG.

  Referring to the drawings, a cabin lifting / lowering device 1 is provided on an upper body 2 mounted on a self-propelled traveling body (for example, a crawler traveling body or the like: not shown) of a work machine. The cabin 3 is raised and lowered with respect to the upper body 2.

  Specifically, the lifting device 1 includes a bracket 4 erected on the upper body 2, and a parallel link mechanism 5 having an upper link 5 a and a lower link 5 b provided between the bracket 4 and the cabin 3. , A hydraulic cylinder 6 for rotating the upper link 5a with respect to the bracket 4, a hydraulic circuit 7 for supplying hydraulic oil to the hydraulic cylinder 6, and a controller (control means) for controlling the flow of hydraulic oil by the hydraulic circuit 7 8 and.

  The bracket 4 includes a bracket main body 9 (one is shown in the figure) that forms a pair on the upper body 2 and axes J1, J2, and J3 extending between the bracket main bodies 9. In the following description, the direction in which the bracket body 9 faces (the direction in which the axes J1 to J3 extend) is the left-right direction, and the direction perpendicular to the left-right direction and the up-down direction is the front-back direction.

  The shafts J1 and J2 are arranged vertically above and below the bracket body 9, the shaft J1 rotatably supports the base end of the upper link 5a, and the shaft J2 rotatably supports the base end of the lower link 5b. Yes. On the other hand, the shaft J3 is provided at the lower portion of the bracket body 9, and rotatably supports the base end portion of the hydraulic cylinder 6.

  The upper link 5a and the lower link 5b are each formed in a plate shape, and the lower link 5b is provided with a hole (not shown) for inserting a hydraulic cylinder 6 to be described later in place. Further, the leading ends of the upper link 5a and the lower link 5b are rotatably supported by shafts J4 and J5 with respect to the cabin bracket 3a formed at the rear portion of the cabin 3.

  The hydraulic cylinder 6 includes a cylinder body 10 pivotally supported on the bracket body 9 by the shaft J3, a rod 11 that can be expanded and contracted with respect to the cylinder body 10, and a stroke sensor that can detect the expansion and contraction position of the rod 11. The position detection means 12 is provided, and the tip of the rod 11 is pivotally supported with respect to the middle portion of the upper link 5a by an axis J6 along the left-right direction.

  When the rod 11 of the hydraulic cylinder 6 is extended, the links 5a and 5b can be rotated to raise the cabin 3. On the other hand, the rod 11 is shortened to link the link 5a in the opposite direction. The cabin 3 can be lowered by rotating 5b.

  Specifically, the cabin 3 includes an upper stop position (position shown in FIG. 1) set on the near side of the upper limit position when the rod 11 reaches the stroke end on the extension side of the cylinder body 10, and the rod 11 The cylinder body 10 is movable up and down between a lower stop position set on the near side of the lower limit position when the stroke end of the shortened side of the cylinder body 10 is reached. At this lower stop position, the cabin 3 is lowered to the vicinity of the upper surface of the upper body 2.

  The position detection means 12 detects whether or not the rod 11 has reached a specific position (hereinafter referred to as a stop operation start position) that is shorter than the extended position corresponding to the upper stop position. That is, the position detection means 12 is configured to be able to detect that the cabin 3 has reached a specific position below the upper stop position.

  Further, the position detection means 12 can detect whether or not the rod 11 has reached a specific position (stop operation start position) extended from a shortened position corresponding to the lower stop position. That is, the position detection means 12 is configured to be able to detect that the cabin 3 has reached a specific position above the lower stop position.

  The stop operation start position is such that the cabin 3 stops at the upper stop position or the lower stop position when the rod 11 starts the stop operation from the time when the rod 11 reaches the stop operation start position. 11 is set in consideration of the response time required for stopping 11.

  Hereinafter, the hydraulic circuit 7 and the controller 8 of the lifting apparatus 1 will be described with reference to FIG.

  The hydraulic circuit 7 includes a drive pump 14 that drives the hydraulic cylinder 6 and a pilot pump 15 that adjusts the flow rate of hydraulic fluid from the drive pump 14 to the hydraulic cylinder 6.

  The drive pump 14 supplies hydraulic oil to the hydraulic cylinder 6 via a pilot-type three-position switching valve (supply / discharge valve) 16.

  The three-position switching valve 16 is held at the neutral position C when no hydraulic oil is supplied to any of the pilot ports 16a and 16b, and is switched to the switching position A when the hydraulic oil is supplied to the pilot port 16a. When the hydraulic oil is supplied to the pilot port 16b, it is switched to the switching position B.

  At the switching position A, the hydraulic oil from the drive pump 14 is supplied into the shortened side chamber 6a of the rod 11 of the hydraulic cylinder 6 and the hydraulic oil is discharged from the extension side chamber 6b. At the neutral position C, the supply and discharge of hydraulic fluid from the drive pump 14 to the hydraulic cylinder 6 are stopped. At the switching position B, the hydraulic oil from the driving pump 14 is supplied into the extension side chamber 6b of the rod 11 of the hydraulic cylinder 6 and the hydraulic oil is discharged from the shortened side chamber 6a.

  Further, the three-position switching valve 16 changes the hydraulic oil to the hydraulic cylinder 6 by changing the stroke from the neutral position C to the switching position A or the switching position B depending on the pilot pressure of the hydraulic oil with respect to the pilot ports 16a and 16b. It is possible to adjust the supply flow rate.

  Reference numeral 17 denotes a relief valve. When the hydraulic oil pressure in the hydraulic system from the driving pump 14 to the hydraulic cylinder 6 via the three-position switching valve 16 becomes equal to or higher than a predetermined pressure, It is designed to release the pressure.

  On the other hand, the pilot pump 15 supplies hydraulic oil to the pilot port 16a via the electromagnetic switching valve 18, and supplies hydraulic oil to the pilot port 16b via the electromagnetic switching valve 19. Yes.

  The electromagnetic switching valves 18 and 19 are held at the switching position D when no current is supplied to the solenoid from the controller 8 (described later), while being switched to the switching position E when current is supplied to the solenoid. It has become.

  At the switching position D, the supply of hydraulic oil to the pilot port 16a or the pilot port 16b is stopped, while at the switching position E, the hydraulic oil is supplied to the pilot port 16a or the pilot port 16b.

  That is, when the electromagnetic switching valve 18 is operated to the switching position E, the pilot pressure is applied to the pilot port 16a, whereby the three-position switching valve 16 is operated to the switching position A, and the shortened side chamber of the hydraulic cylinder 6 is operated. The hydraulic oil is supplied into 6a and the hydraulic oil is discharged from the extension side chamber 6b, so that the cabin 3 is lowered. Hereinafter, the electromagnetic switching valve 18 is referred to as a lowering switching valve 18.

  When the electromagnetic switching valve 19 is operated to the switching position E, the pilot pressure is applied to the pilot port 16b, whereby the three-position switching valve 16 is operated to the switching position B, and the expansion side chamber of the hydraulic cylinder 6 is operated. The hydraulic oil is supplied into 6b and the hydraulic oil is discharged from the shortened side chamber 6a, and the cabin 3 is raised. Hereinafter, the electromagnetic switching valve 19 will be referred to as the ascending side switching valve 19.

  The controller 8 that electrically controls the operation of the ascending side switching valve 19 and the descending side switching valve 18 has the position detecting means 12 and an operation unit 20 to which an operation for raising or lowering the cabin 3 is input by the occupant. Are electrically connected to each other.

  The operation unit 20 is an input means including an operation lever or the like, and is normally in a neutral position and is in a state in which the input operation is released. When the operation unit 20 is operated from the neutral position to one or the other, the cabin 3 is raised. Alternatively, it is possible to input a descent.

  And the controller 8 performs the process demonstrated below by operating each switching valve 18 and 19 based on the signal input from the position detection means 12 and the operation part 20. FIG.

  FIG. 3 is a flowchart showing processing executed by the controller of FIG.

  2 and 3, when the process by the controller 8 is executed, the ascending side switching valve 19 is actuated in response to the input of the ascending operation by the operating unit 20 (YES in step S1) (see FIG. 2 and FIG. 3). Step S2: supply step).

  That is, by switching the ascending side switching valve 19 to the switching position E, hydraulic oil is supplied from the pilot pump 15 to the pilot port 16b of the three-position switching valve 16, so that the three-position switching valve 16 is switched to the switching position B. As a result, the hydraulic fluid is supplied from the driving pump 14 to the extension side chamber 6b of the hydraulic cylinder 6 and the hydraulic fluid is discharged from the shortened side chamber 6a of the hydraulic cylinder 6. As a result, the cabin 3 starts to rise.

  Next, it is determined by the position detection means 12 whether or not the rod 11 has reached the stop operation start position, that is, whether or not the cabin 3 has reached a position just before the upper stop position (step S3), and the stop is started. If it is determined that the position has been reached (YES in step S3), the operation of the ascending side switching valve 19 is stopped (step S4: stop process).

  That is, by returning the ascending side switching valve 19 to the switching position D, the supply of hydraulic oil to the pilot port 16b is stopped, and the three-position switching valve 16 is also returned to the neutral position C along with this, and the hydraulic cylinder The supply of hydraulic oil to 6 and the discharge of hydraulic oil from the hydraulic cylinder 6 are stopped.

  In step S4, the supply and discharge of the hydraulic oil to and from the hydraulic cylinder 6 is stopped from the time when the stop operation start position is reached, but the three-position switching valve 16 is returned from the switching position B to the neutral position C. In the meantime, the supply and discharge of the hydraulic oil to and from the hydraulic cylinder is not instantaneously stopped, but is gradually stopped, so that the cabin 3 stops at a position advanced by a predetermined distance from the time of arrival. Become.

  That is, a slight response time occurs between the time when the arrival at the stop operation start position is confirmed and the time when the cabin 3 is completely stopped. However, since the response time is taken into consideration, the cabin 3 is set at a position lower than the upper stop position, so that the cabin 3 can be stopped at the upper stop position by executing step S4.

  As described above, according to the lifting / lowering device 1, the cabin 3 is moved in a range below the upper stop position set in front of the upper limit position when the rod 11 of the hydraulic cylinder 6 reaches the stroke end. Since it is configured to stop, it is possible to prevent the cabin 3 from stopping at the upper limit position where the rod 11 reaches the stroke end.

  Thus, unlike the situation where the rod 11 is pressed against the stroke end at a high pressure by stopping the rod 11 at a position on the near side of the stroke end, that is, in the middle position, the rod 11 is stretched to some extent. The situation can be displaced.

  That is, as shown in FIG. 2, when the rod 11 reaches the stroke end, the rod 11 is pressed against the stroke end at a high pressure, so the inside of the shortening side chamber 6 a or the expansion side chamber 6 b is defined by the relief valve 17. However, the rod 11 hardly expands or contracts even when an external force is applied. However, the rod 11 is stopped on the near side of the stroke end as in the above embodiment, so that the shortened side chamber 6a or It is possible to suppress the pressure in the extension side chamber 6b from rising to the specified pressure of the relief valve 17.

  Therefore, even when the work is performed in the state where the cabin 3 is set to the upper stop position and the vibration generated in the traveling body or the upper body is added to the rod 11 during the work, the rod 11 is moved to the cylinder according to the vibration. When the hydraulic oil in the main body 10 expands and contracts while being compressed, the hydraulic cylinder 6 acts as a damper and can effectively absorb the vibration.

  Specifically, according to the embodiment in which the rising of the cabin 3 is stopped when the rod 11 reaches the stop operation start position by the position detecting means 12, the cabin 3 is moved in the stage before reaching the upper limit position. By stopping, the cabin 3 can be stopped in the process of ascending, so that the time for raising the cabin 3 can be shortened compared with the case where the cabin 3 is once driven to the upper limit position and then returned to the upper stop position.

  In the above description, only control for raising the cabin 3 has been described. However, similar processing can be executed when lowering the cabin 3. That is, if it is determined in step S1 that the lowering operation has been input, the lowering switching valve 18 is actuated in step S2, and the rod 11 is in front of the shortened stroke end (target stop position) in step S3. ), It is only necessary to stop the operation of the descending switching valve 18 in step S4.

  Moreover, although the said embodiment demonstrated the example which employ | adopted the stroke sensor as the position detection means 12, the angle sensor which detects the rotational position of each said link 5a, 5b (refer FIG. 1), each link 5a, It is also possible to employ a limit switch that is turned on or off in accordance with the operation of 5b.

  Further, in the above-described embodiment, when it is detected that the rod 11 has reached the stop operation start position, the expansion and contraction of the rod 11 is stopped. However, after the rod 11 reaches the stroke end, the cabin 3 is moved. It may be lowered.

  That is, the position detection means 12 is configured to be able to detect whether or not the rod 11 has reached the extension stroke end, that is, whether or not the cabin 3 has reached the upper limit position. The effects described above can be obtained by executing the following processing.

  FIG. 4 is a flowchart illustrating processing executed by the controller according to another embodiment.

  2 and 4, when the process by the controller 8 is executed, the ascending side switching valve 19 is actuated in response to the input of the ascending operation by the operation unit 20 (YES in step T1) (see FIG. 2 and FIG. 4). Step T2: Supply / discharge process).

  That is, by switching the ascending side switching valve 19 to the switching position E, hydraulic oil is supplied from the pilot pump 15 to the pilot port 16b of the three-position switching valve 16, so that the three-position switching valve 16 is switched to the switching position B. As a result, the hydraulic oil is supplied from the drive pump 14 to the extension chamber 6b of the hydraulic cylinder 6 and discharged from the shortened side chamber 6a of the hydraulic cylinder 6. As a result, the cabin 3 starts to rise.

  Next, it is determined by the position detection means 12 whether or not the rod 11 has reached the stroke end, that is, whether or not the cabin 3 has reached the upper limit position (step T3), and is determined to have reached the stroke end. When done (YES in step T3), the operation of the ascending side switching valve 19 is stopped (step T4).

  That is, by returning the ascending side switching valve 19 to the switching position D, the supply of hydraulic oil to the pilot port 16b is stopped, and the three-position switching valve 16 is also returned to the neutral position C along with this, and the hydraulic cylinder The supply of hydraulic oil to 6 and the discharge of hydraulic oil from the hydraulic cylinder 6 are stopped.

  Next, the lowering side switching valve 18 is operated (step T5), that is, the lowering side switching valve 18 is switched to the switching position E, whereby hydraulic oil is supplied from the pilot pump 15 to the pilot port 16a of the three-position switching valve 16. As a result, the three-position switching valve 16 is switched to the switching position A, and hydraulic oil is supplied from the driving pump 14 to the shortening side chamber 6a of the hydraulic cylinder 6 and is operated from the expansion side chamber 6b of the hydraulic cylinder 6. As a result of the oil being discharged, the cabin 3 starts to descend (reverse drive process).

  Next, the operation of the lowering switching valve 18 is continued until a predetermined time (for example, 1 second) set in advance (YES in Step T6) (Step T5).

  Here, the specified time is a time set in advance corresponding to a moving distance (predetermined amount) from the upper limit position to the upper stop position, and includes the response time when the cabin 3 is stopped. Is. Therefore, when the specified time has elapsed (YES in step T6), the cabin 3 can be stopped at the upper stop position by stopping the operation of the descending switching valve 18 (step T7: stop process).

  As described above, according to the embodiment in which the cabin 3 is lowered by a predetermined time (predetermined amount) after the position detection unit 12 detects that the cabin 3 has reached the upper limit position, the cabin by the position detection unit 12 is used. Even if there is some error in the position detection of 3, the cabin 3 can be reliably stopped at the upper stop position or a lower position than this.

  That is, in the above embodiment, when the actual position of the cabin 3 detected as having reached the upper limit position by the position detection unit 12 is not the upper limit position (for example, when an error has occurred in the position detection unit 12). Even so, since the cabin 3 is further lowered by a predetermined amount from the current position, the cabin 3 can be stopped at least at a position below the upper stop position regardless of the position at the time of position detection. In other words, it is possible to reliably avoid the rod 11 from stopping at the stroke end.

  In the above description, only the control for raising the cabin 3 has been described. However, the position detection means 12 is used to determine whether the rod 11 has reached the shortened stroke end, that is, the cabin 3 By configuring so as to be able to detect whether or not the lower limit position has been reached, the same processing can be executed when the cabin 3 is lowered.

  That is, when it is determined in step T1 that the lowering operation is input, the lowering switching valve 18 is operated in step T2, and in the case where it is determined in step T3 that the cabin 3 has reached the lower limit position. In step T4, the lower side switching valve 18 is stopped, and in step T5 and step T6, the upward side switching valve 19 is operated for a specified time, and the upward side switching valve 19 can be stopped in step T7. Thereby, the cabin 3 can be stopped at the lower stop position.

  Moreover, although the said embodiment demonstrated the example which employ | adopted the stroke sensor as a position detection means, the pressure sensor which detects the pressure in the shortening side chamber 6a or the expansion | extension side chamber 6b of the said hydraulic cylinder 6 can also be employ | adopted. .

  Further, in the above embodiment, the position detecting means 12 for detecting the position of the rod 11 is provided. However, the position detecting means 12 can be omitted by executing the processing of the controller 8 described below.

  FIG. 5 is a flowchart illustrating processing executed by the controller according to another embodiment.

  2 and 5, when the process by the controller 8 is executed, the ascending side switching valve 19 is actuated in response to the input of the ascending operation by the operation unit 20 (YES in step U1) (see FIG. 2 and FIG. 5). Step U2).

  That is, by switching the ascending side switching valve 19 to the switching position E, hydraulic oil is supplied from the pilot pump 15 to the pilot port 16b of the three-position switching valve 16, so that the three-position switching valve 16 is switched to the switching position B. As a result, the hydraulic fluid is supplied from the driving pump 14 to the extension side chamber 6b of the hydraulic cylinder 6 and the hydraulic fluid is discharged from the shortened side chamber 6a of the hydraulic cylinder 6. As a result, the cabin 3 starts to rise.

  When the input of the ascending operation is released (YES in step U3), the ascending side switching valve 19 is stopped (step U4).

  Next, the descent-side switching valve 18 is operated (step U5) until a preset specified time (for example, 1 second) elapses (YES in step U6).

  Here, the specified time is a time set in advance corresponding to a moving distance (predetermined amount) from the upper limit position to the upper stop position, and includes the corresponding time when the cabin 3 is stopped. Is. Accordingly, when the specified time has elapsed (YES in step U6), the operation of the lower side switching valve 18 is stopped (step U7), and the cabin 3 is stopped after the cabin 3 is lowered by the moving distance. Can be made.

  Therefore, if the cabin 3 is in the upper limit position at the time of release of the ascending operation input (YES in step U3), the cabin 3 can be stopped at the upper stop position by lowering for the predetermined time. it can.

  As described above, according to the embodiment in which the cabin 3 is lowered when the operation by the operation unit 20 is released, according to the release of the raising operation of the cabin 3 by the operation unit 20, at the time of the operation release. Regardless of the position of the cabin 3, the cabin 3 can be lowered by a predetermined amount.

  Therefore, even when the cabin 3 has already reached the upper limit position during the ascending operation by the operation unit 20, the operation of the operation unit 20 is subsequently released, so that the cabin 3 is moved from the upper limit position by a predetermined amount. Since the vehicle is lowered, the cabin 3 can be reliably stopped at the upper stop position or the lower position without using a detection means for detecting the position of the cabin 3 or the like.

  In the above description, only control for raising the cabin 3 has been described. However, similar processing can be executed when lowering the cabin 3. That is, if it is determined in step U1 that the lowering operation is input, the lowering switching valve 18 is operated in step U2, and if it is determined in step U3 that the operation by the operation unit 20 is released, The descending switching valve 18 is stopped at U4, the ascending switching valve 19 is operated for a specified time at steps U5 and U6, and the ascending switching valve 19 can be stopped at step U7. Thereby, when the cabin 3 has reached the lower limit position when the operation unit 20 is released, the cabin 3 can be stopped at the lower stop position.

  Moreover, in each said embodiment, although the parallel link mechanism 5 was illustrated as a means to hold | maintain the cabin 3 so that raising / lowering is possible, the form of this holding means is not specifically limited. That is, as the holding means, for example, a vertical rail type holding means for slidably connecting a rail erected on the upper body 2 and a slider provided in the cabin 3 or a lower surface of the cabin 3 is provided. A pantograph type holding means held by a frame with a rhombus joint can also be employed.

1 is a side view schematically showing a cabin lifting / lowering device according to an embodiment of the present invention, showing a state where the cabin is in a raised position. It is a circuit diagram which shows the hydraulic and electrical structure of the raising / lowering apparatus of FIG. It is a flowchart which shows the process performed by the controller of FIG. It is a flowchart which shows the process performed by the controller of another embodiment. It is a flowchart which shows the process performed by the controller of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lifting apparatus 2 Upper body 3 Cabin 5 Parallel link mechanism 6 Hydraulic cylinder 6a Short side chamber 6b Extension side chamber 8 Controller (control means)
11 Rod 12 Position detecting means 16 3 Position switching valve (supply / discharge valve)
20 Operation unit

Claims (8)

A cabin elevating device having a hydraulic cylinder that elevates and lowers a cabin held up and down on the upper body mounted on a self-propelled traveling body of a work machine,
A supply / discharge valve for adjusting supply and discharge of hydraulic oil to and from the hydraulic cylinder;
Control means for controlling the expansion and contraction operation of the rod of the hydraulic cylinder by operating this supply and discharge valve,
The control means stops the cabin in a range below the upper stop position set on the near side of the upper limit position when the rod of the hydraulic cylinder reaches the stroke end. .   It further comprises position detection means capable of detecting that the cabin has reached a specific position below the upper stop position, and the control means is configured to stop the cabin at the upper stop position. The cabin is stopped at the upper stop position before the cabin reaches the upper limit position by stopping the expansion and contraction operation of the rod based on the time point when the cabin is detected by The cabin lifting apparatus according to 1.   Position detecting means for detecting whether or not the cabin has reached the upper limit position, and the control means stops the cabin at the upper stop position, and the position detecting means causes the cabin to reach the upper limit position. The cabin lifting / lowering apparatus according to claim 1, wherein after the arrival is detected, the cabin is lowered from the upper limit position by a predetermined amount.   An operation unit that receives a command operation for raising and lowering the cabin from an occupant is further provided, and the control unit lowers the cabin by a predetermined amount when the raising command operation of the operation unit is released. The cabin elevating device according to claim 1.   The control means raises the cabin from a lower stop position set on the near side of the lower limit position when the rod of the hydraulic cylinder reaches the stroke end opposite to the stroke end corresponding to the upper limit position. The cabin elevating device according to any one of claims 1 to 4, wherein the cabin elevating device is stopped in a range of. A method of raising a cabin held on the upper body so as to be movable up and down with respect to an upper body mounted on a self-propelled traveling body of a work machine,
A supply and discharge step of raising the cabin by supplying hydraulic oil into one chamber of the hydraulic cylinder for raising and lowering the cabin and discharging hydraulic oil from the other chamber;
By stopping the supply and discharge of the hydraulic oil, the cabin is stopped in the range below the upper stop position set on the near side of the upper limit position when the rod of the hydraulic cylinder reaches the stroke end. A cabin driving method comprising: a stopping step.   In the stop step, it is confirmed whether or not the cabin has reached a specific position below the upper stop position, and by stopping the supply and discharge of the hydraulic oil based on the confirmed time point, The cabin driving method according to claim 6, wherein the cabin is stopped from rising before the cabin reaches the upper limit position.   In the stop step, it is confirmed whether or not the cabin has reached the upper limit position, and after confirming that the cabin has reached the upper limit position in the stop step, hydraulic oil is supplied to the other chamber. The cabin driving method according to claim 6, further comprising a reverse driving step of lowering the cabin by a predetermined amount from the upper limit position by discharging the hydraulic oil in the one room.

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