JP4326497B2 - Working vehicle lifting / lowering operation structure - Google Patents

Description

  In the present invention, in conjunction with the operation of the height setting lever, the height setting lever is controlled so that position control for raising and lowering the work device to a height position corresponding to the operation position of the height setting lever is performed. An operation provided with a one-sided linking portion that enables a one-sided operation that resists the operation bias to the lowering side of the control valve on a control valve that controls the operation of a hydraulic operation mechanism that raises and lowers the work device. Mechanical linkage via the linkage mechanism, and a feedback linkage mechanism that feeds back the operation of the hydraulic operation mechanism to the manipulation linkage mechanism. Automatic raising control is performed to automatically raise the working device to a set upper limit position and disable the position control, and based on the lowering command operation of the lifting command means, the height The electric actuator is mechanically linked to the one-sided linkage part and the lifting / lowering is performed so that automatic lowering control that enables the position control is performed while the working device is automatically lowered to a height position set by a constant lever. The present invention relates to a lifting / lowering operation structure for a work vehicle provided with control means for controlling the operation of the electric actuator based on an operation of command means.

As described above, the work vehicle is lifted and lowered by swinging the height setting lever to the end position in the ascending direction when the work device is automatically raised to the upper limit position by automatic ascent control. When the pressing operation is performed, the electric motor is reversely operated by the control operation of the control device based on the operation, so that the work device is automatically lowered to the height position set by the height setting lever and the automatic lowering control enabling position control. Is configured to be performed (see, for example, Patent Document 1).
JP 2003-333902 A

  In the above configuration, the height position of the working device when the height setting lever is swung to the end position in the upward direction in which the upper limit detection switch is pressed, and the working device is moved to the upper limit position by the forward rotation operation of the electric motor. If the height of the work equipment when it is automatically raised does not match, the height setting lever will swing to the end position in the ascending direction when the work equipment is automatically raised to the upper limit by automatic elevation control. When the upper limit detection switch is operated and the upper limit detection switch is operated, if the upper limit position of the work device by the swing operation of the height setting lever is higher than the upper limit position of the work device by the forward rotation operation of the electric motor, the height setting lever Until the upper limit detection switch is pressed, the work device that should not be raised by this operation is inadvertently raised, and conversely, the upper limit position of the work device by the swinging operation of the height setting lever is changed. When it is lower than the upper limit position of the working device due to the forward rotation operation of the dynamic motor, the height setting lever presses the upper limit detection switch, and at the same time, the automatic lowering control is performed by the control operation of the control device based on the operation In this operation, the work apparatus that should not be lowered will be inadvertently lowered. To avoid this inconvenience, the operation of each part in the operation linkage mechanism and the feedback linkage mechanism is carefully adjusted. Since the necessity arises, the assembling property is lowered.

  In addition, when the operator accidentally performs a key-off operation or the like and turns off the power during the automatic ascent control, and the work device stops in the middle of ascending to the upper limit position, the state is not noticed. If you try to raise or lower the work device by operating the height setting lever, the height setting lever is operated above the previous stop position of the work device without being restricted by the operation of the electric motor stopped during operation. Although the work device can be moved up and down in conjunction with the position of the work device, the position of the work device can be controlled by operating the height setting lever. As a result, it becomes impossible to control the position of the work device by operating the height setting lever, because the work device cannot be moved up and down in conjunction with the operation of the height setting lever. That disadvantage will be occur, there is a possibility to mistaking failed worker.

  It is an object of the present invention to avoid the inconvenience that the working device moves up and down unexpectedly when position control is possible by operating the height setting lever after performing automatic ascent control without degrading assembling performance, and automatic ascent control. An object of the present invention is to avoid the lifting failure of the working device that occurs when the working device is raised and stopped by mistake during the operation.

  In the invention according to claim 1 of the present invention, position control for raising and lowering the working device to a height position corresponding to the operation position of the height setting lever is performed in conjunction with the operation of the height setting lever. As described above, the height setting lever can be operated in a one-sided manner against a control valve that controls the operation of a hydraulic operation mechanism that moves the working device up and down against the biasing of the control valve toward the lower side. Mechanically linked via an operation linkage mechanism having a piece-by-piece linkage portion, and a feedback linkage mechanism that feeds back the operation of the hydraulic operation mechanism to the operation linkage mechanism. On the basis of the lift command operation of the means, the work device is automatically lifted to a preset upper limit position, and automatic lift control is performed to disable the position control. Based on the command operation, the one-piece linkage unit is electrically driven so that the work apparatus is automatically lowered to the height position set by the height setting lever and automatic lowering control is performed to enable the position control. A lever position for detecting an operating position of the height setting lever in a lifting / lowering operation structure of a work vehicle provided with a control means for controlling the operation of the electric actuator based on an operation of the lifting / lowering command means while linking the actuator to the machine And a height position detecting means for detecting a height position of the working device, and the control means stores a correlation between an output of the lever position detecting means and an output of the height position detecting means. The lever corresponding to the output of the height position detecting means based on the output of the height position detecting means and the correlation.置検 out to determine the output target value of the unit, and are configured to perform the auto down control when the output value of the lever position detecting means to the target output values match.

  According to this configuration, in a state in which the working device is raised by the automatic raising control, the control means outputs the output target of the lever position detecting means based on the output value of the height position detecting means and the stored correlation. If the height setting lever is operated in this state, automatic lowering control is not performed and position control is not possible until the output value of the lever position detection means matches the output target value. If the output value of the lever position detection means coincides with the output target value, automatic lowering control is performed and position control becomes possible, so the height setting lever corresponds to the operating position of the height setting lever. The working device can be positioned.

  By the way, when the output of the lever position detecting means coincides with the output of the height position detecting means in the state where the working device is simply raised by the automatic raising control, the automatic lowering control is performed and the position control is performed. When configured to be possible, the height position of the work device based on the height position of the work device corresponding to the output of the height position detection means and the operation position of the height setting lever corresponding to the output of the lever position detection means Since there is no relationship between the operation position of the height setting lever corresponding to the output of the lever position detection means rather than the height position of the working device corresponding to the output of the height position detection means. When the height position of the working device based on the above is high, the automatic lowering control is not performed and the position control is disabled until the output of the lever position detecting means coincides with the output of the height position detecting means. is there Although the working device does not move up and down, the automatic lowering control is performed and the position control becomes possible as the output of the lever position detecting means coincides with the output of the height position detecting means. The working device rises unexpectedly to a height position based on the operation position, and conversely, it corresponds to the output of the lever position detecting means rather than the height position of the working device corresponding to the output of the height position detecting means. When the height position of the working device based on the operation position of the height setting lever is low, the automatic lowering control is not performed until the output of the lever position detecting means coincides with the output of the height position detecting means. Although the work device does not move up and down because position control is still disabled, automatic lowering control is performed as the output of the lever position detection means matches the output of the height position detection means. If your is enabled, the working device comes to descend unexpectedly to a height position based on the operating position of the height setting lever.

  In other words, in the state where the work device is lifted by the automatic lift control, when the output of the lever position detection means coincides with the output of the height position detection means at this time, the automatic lowering control is performed and the position control is possible. If only the above configuration is adopted, it is impossible to avoid the inconvenience that the working device moves up and down unexpectedly when the position control is enabled by operating the height setting lever after performing the automatic ascent control.

  Therefore, in the invention described in claim 1 of the present invention, the correlation between the output of the lever position detecting means and the output of the height position detecting means, that is, the height setting lever is operated over the entire operation region. The control means controls the correlation between the output of the lever position detection means obtained at the time and the output of the height position detection means for detecting the height position of the working device that moves up and down in conjunction with the operation of the height setting lever at that time And the control means determines an output target value of the lever position detecting means corresponding to the output of the height position detecting means based on the correlation and the output of the height position detecting means, and this output It is configured to perform automatic lowering control when the output value of the lever position detection means matches the target value. Up During the control, the operator accidentally performs a key-off operation, etc., and turns off the power, so that the operator can operate the height setting lever regardless of whether the work device is stopped on the way to the upper limit position. Even if the output value of the lever position detecting means coincides with the target output value of the lever position detecting means determined by the control means, the work device can be lifted or lowered unless the height setting lever is operated from the operation position at that time. In addition, when the height setting lever is operated from the operation position at that time, the work device is moved up and down to a height position corresponding to the operation position of the height setting lever.

  Incidentally, as the correlation between the output of the lever position detection means and the output of the height position detection means stored in the control means, the sampled value, or a relative relational expression obtained from the sampled value, etc. can be considered. The number of sampling values to be stored varies from one to many according to the similarity between the output of the upper limit position setting means and the output of the lever position detection means obtained by the operation for establishing the correlation. Is possible.

  Therefore, when position control can be performed by operating the height setting lever after performing automatic ascent control without degrading assemblability, the work device will not move up and down unexpectedly, or during automatic ascent control. It is possible to prevent the lifting / lowering of the working device that occurs when the working device is erroneously stopped and stopped.

  According to a second aspect of the present invention, in the first aspect of the present invention, the contact that restricts the operation of the height setting lever in the upward direction by the contact with the height setting lever. Equipped with an expression limiting means so that the position can be changed, and provided with an upper limit position setting means for enabling the setting change of the upper limit position in the automatic ascent control, the contact type limiting means and the upper limit position setting means, Mechanically linked so that the setting change operation of the upper limit position setting means is performed in conjunction with the position change operation of the contact type restriction means, and the output of the upper limit position setting means and the height position detection means are connected to the control means. And the control means, based on the output of the upper limit position setting means and the correlation between the output of the upper limit position setting means and the output of the height position detection means, Corresponds to the output of the upper limit position setting means The output target value of the height position detecting means is determined, and the automatic elevation control controls the operation of the electric actuator until the output value of the height position detecting means matches the determined output target value. It is constituted as follows.

  According to this configuration, if the contact type restricting means is operated to change the position, the height of the working device corresponding to the operation limit position of the height setting lever determined by the operation position of the contact type restricting means after the position change is performed. The position becomes the upper limit position of the working device in the position control, and the operation position of the upper limit position setting means (the output value of the upper limit position setting means) changed in conjunction with the position change operation of the contact type restriction means The height position of the corresponding working device (the output value of the height position detecting means) becomes the upper limit position of the working device in the automatic ascent control.

  In other words, when the work vehicle is additionally equipped with a cabin in order to improve the work environment, or when the work device is replaced to perform other work, the position change operation of the contact type restriction means is performed. The upper limit position in the position control of the work device and the upper limit position in the automatic ascent control can be set and changed at once to a height position at which the work device can avoid contact with the cabin on the work vehicle side. Therefore, compared with the case where the upper limit position in the position control of the work device and the upper limit position in the automatic ascent control are individually set and changed, the setting change operation of the upper limit position can be easily performed. It is possible to avoid the possibility that the working device may come into contact with the cabin or the like on the work vehicle side due to forgetting to change the upper limit position.

  By the way, the upper limit position of the working device in the position control is the upper limit position of the mechanical working device obtained when the height setting lever is operated to the operation limit position that is in contact with the contact-type limiting means. The upper limit position of the working device in the automatic ascent control is the upper limit position of the electric working device obtained when the electric actuator is operated by the control operation of the control means based on the operation of the raising / lowering command means. Therefore, even if the contact-type limiting means and the upper limit position setting means are merely mechanically linked, their upper limit positions do not match.

  On the contrary, the contact type limiting means is functionally changed in position by a sliding operation along a lever guide or the like indicating the operation position of the height setting lever. Since it is common to employ a rotary potentiometer that is operated to rotate, if the contact-type limiting means and the upper limit position setting means are mechanically linked, the contact-type restriction is limited due to the difference in their operation modes. In the operation of the upper limit position setting means linked to the position change operation of the means, it will be affected by the operation of the link etc. in the linkage mechanism that links them, thereby moving the contact type restriction means along the lever guide When this is done, not only will there be a difference between the operation amount of the contact-type limiting means and the operation amount of the upper limit position setting means, but the difference will change depending on the operation position. Since the obtained output (operation position) of the upper limit position setting means draws a curve instead of a straight line indicating a proportional relationship with the operation position of the contact type restriction means, the upper limit in the position control of the work device is simply Not only does the position do not match the upper limit position in automatic ascent control, but the difference will change depending on the setting of the upper limit position. When the position is raised to the position, the working device is raised more than expected, which may cause inconvenience in contact with the cabin or the like on the work vehicle side.

  In order to avoid this inconvenience, it is conceivable to establish a proportional relationship between the operation position of the contact-type limiting means and the operation position of the upper limit position setting means, but in order to establish this proportional relationship. In the linkage mechanism that mechanically links the contact-type limiting means and the upper limit position setting means, it is necessary to provide an adjustment mechanism that enables adjustment of the operation of each part, resulting in a complicated structure, The assembling property is lowered due to the adjustment work.

  Therefore, since the mechanical linkage to the contact type limiting means has no proportional relationship with the operation position of the contact type limiting means, the upper limit position setting means that detects the operation position of the contact type limiting means. The correlation between the output and the output of the height position detecting means for detecting the height position of the work device is stored in the control means, and the control means determines the upper limit based on the relative relationship and the output of the upper limit position setting means. The output target value of the height position detecting means corresponding to the output of the position setting means is determined, and in the automatic ascending control, the electric actuator is operated until the output value of the height position detecting means matches the determined output target value. The linkage mechanism is configured to control the operation of the upper limit position setting means in conjunction with the contact type restriction means and convert the operation of the contact type restriction means to the operation of the upper limit position setting means. Behavior affects When the operation of the linkage mechanism that converts the lifting / lowering operation of the work device into the detection operation (operation) of the height position detecting device affects the detection operation of the height position detecting device linked to the lifting / lowering of the working device. Even so, it is possible to control the operation of the electric actuator in consideration of those effects, and as a result, the position control that appears when the height setting lever is brought into contact with the contact-type limiting means Work with automatic ascending control that appears in the control operation of the control means that controls the operation of the electric actuator based on the upper limit position of the work device at the upper limit, the output of the upper limit position setting means and the output of the height position detection means The upper limit position of the apparatus can be matched.

  The upper limit position of the work device in position control is matched with the upper limit position of the work device in automatic elevation control, so that the upper limit position of the work device is set in automatic elevation control regardless of the setting change of the upper limit position. In this state, the control means determines the output target value of the lever position detection means based on the output value of the height position detection means at this time and the stored correlation. When the height setting lever is operated with, until the output target value matches the output value of the lever position detection means, the automatic lowering control is not performed and position control remains impossible. When the output values of the position detection means match, automatic descent control is performed and position control becomes possible. Even if the output value of the lever position detection means matches the output target value, the operation at that time is performed. Unless the height setting lever is operated from the position, the work device does not move up and down.When the height setting lever is operated from the current operation position, the work device is moved to a height position corresponding to the operation position of the height setting lever. It goes up and down.

  Incidentally, the correlation between the output of the upper limit position setting means and the output of the height position detection means is, for example, the height setting lever operated along the lever guide in the operation area of the height setting lever and the contact type limiting means. Can be established by acquiring a sampled value from the output of the upper limit position setting means and the output of the height position detection means obtained when the two are moved in the same direction at the same speed.

  Further, as the correlation stored in the control means, the sampled value or a relative relational expression obtained from the sampled value can be considered, and the number of sampled values to be stored is used to establish the correlation. Depending on the similarity between the output curve of the upper limit position setting means obtained by the above operation and the output curve of the height position detection means, various changes from one to many can be made.

  Therefore, it is possible to improve the operability and reliability when changing the upper limit position of the work device according to the additional equipment of the cabin or the replacement of the work device, and the upper limit position in the position control of the work device is automatically set. Automatic lift regardless of changes in the upper limit position of the work equipment, while avoiding contact with the cabin on the vehicle body side of the work equipment due to differences in the upper limit position in the lift control Work that occurs when the work equipment moves up and down unexpectedly when position control is enabled by operating the height setting lever after control, or when the work equipment is lifted and stopped by mistake during automatic lift control It is possible to avoid an elevation failure of the apparatus.

  In the invention according to claim 3 of the present invention, in the invention according to claim 1 or 2, the control means performs the automatic elevation control based on the elevation command from the elevation command means, and The normal mode for performing the automatic lowering control based on the lowering command from the lifting command means, and the electric actuator is operated while the rising command is continuously input based on the lifting command from the lifting command means. And performing the manual ascent control to raise the working device, and based on the descending command from the ascending / descending command means, while the descending command is continuously input, the electric actuator is operated to operate the working device. A special mode for performing manual lowering control for lowering, and mode switching means for instructing the control means to switch the control mode to be executed.

  According to this configuration, when the control mode of the control device is switched to the special mode by operating the mode switching means, the electric actuator can be inching-operated by the ascending command from the ascending / descending command means. A subtle positional shift when linked to the type linkage unit or the like can be easily adjusted without requiring the trouble of directly connecting the electric actuator to the battery, thereby improving the assembling workability of the lifting operation system.

  Also, if the work equipment stops moving up and down regardless of the lifting command from the lifting command means, switch to the special mode and check whether current is flowing while the lifting command means outputs the lifting command. By doing so, it becomes easy to investigate the cause such as failure of the electric actuator and hydraulic system after the electric actuator or the failure of the control means.

  Accordingly, it is possible to improve the assembling property and the maintenance property.

  In the invention according to claim 4 of the present invention, in the invention according to any one of claims 1 to 3, when the control means is operated simultaneously with a plurality of existing command means, While the command from the command means is continuously input, the existing actuator is operated differently from the combination when performing the manual lift control for operating the electric actuator to lift the work device and performing the manual lift control. When a plurality of command means are operated simultaneously, manual lowering control is performed to operate the electric actuator and lower the working device while commands from these command means are continuously input. is there.

  According to this configuration, when the work device does not move up and down by the operation of the electric actuator according to the command from the lift command means, the work device is moved up and down by simultaneously operating a plurality of preset command means. Then, the command from the lift command means makes it easy to investigate the cause when the working device stops moving up and down, and when the cause is a failure of the lift command means, the plurality of existing preset By simultaneously operating the command means, the work device can be lifted and lowered by the operation of the electric actuator. As a result, after the work device is raised to the upper limit position by automatic ascent control, Even if the work device cannot be lifted or lowered by the operation of the actuator, the work device is operated by simultaneously operating a plurality of preset command means. If so lowering allows continued work to be able to enable position control.

  Therefore, it is possible to improve the maintainability and to improve the workability in which the work can be continued even when the lifting / lowering command means is broken and the lifting / lowering operation of the working device cannot be performed by the operation of the electric actuator. .

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, in the automatic lowering control, the electric actuator is previously set by the control operation of the control means. It is configured to operate only for a set time.

  According to this configuration, during the automatic lowering control, the work device is lowered to the height position set by the height setting lever based on the detection from the detection means for detecting the state of the electric actuator, and the position control is performed. It is not necessary to cause the control means to perform a control operation such as controlling the operation of the electric actuator while determining whether or not the electric actuator has been operated to a state where it can be made possible.

  Therefore, the control configuration in the automatic lowering control can be simplified.

  1 and 2 show an entire side surface of a tractor which is an example of a work vehicle. The tractor includes a main clutch (with a clutch housing 2 that includes power from a vibration-proof engine 1 mounted in a front portion). (Not shown) or a transmission system (not shown) installed in the transmission case 3 is configured to be a four-wheel drive type that transmits to a pair of left and right front wheels 4 and rear wheels 5 through a transmission system. A rotary tiller 7, which is an example of a working device that is lifted and lowered by the operation of the hydraulic operating mechanism 6 installed in the rear upper part of the transmission case 3, is connected via a link mechanism 8, and the power to the rotary tiller 7 is as follows. The power is output from the power take-off shaft 9 provided at the rear part of the transmission case 3.

  The tractor includes a specification form (see FIG. 1) in which a substantially gate-shaped protective frame 13 is erected on the rear portion of the boarding operation unit 12 formed by including the steering wheel 10, the driver's seat 11, and the like, and the protective frame. Instead of 13, the specification can be changed to a specification form (see FIG. 2) equipped with a cabin 14 that covers the boarding operation unit 12.

  Further, on the right side of the driver's seat 11, there is provided a front-rear swinging friction holding type height setting lever 15 for setting the height position of the rotary tiller 7, and on the lower right side of the steering wheel 10. An up-down swinging-type lift command lever 16 of a vertically swinging type for instructing a lifting operation to a preset upper limit position or a lowered position of the rotary tiller 7 is provided.

  The hydraulic operation mechanism 6 includes a hydraulic single-acting lifting cylinder 17 provided with a casing 17A that also serves as a lid that closes an opening (not shown) formed on the rear upper surface of the mission case 3, and the lifting and lowering cylinder 17 A pair of left and right lift arms 18 that swings in the vertical direction in conjunction with the operation of the cylinder 17 is provided.

  As shown in FIG. 3, the left and right lift arms 18 are oscillated by controlling the flow of hydraulic oil to the lifting cylinder 17 by a control valve 19 built in the mission case 3, and the control valve 19 is 3 in the neutral state. The position switching type switching valve portion 19A is switched to the neutral position, and the unloading valve portion 19B self-returns to a discharge state that avoids the flow of hydraulic oil from the hydraulic pump 20 to the switching valve portion 19A, and vice versa. The stop valve portion 19C prevents the hydraulic oil from flowing from the lift cylinder 17 to the switching valve portion 19A, and the speed adjustment valve portion 19D is self-disposed at a discharge stop position where the discharge of the hydraulic oil from the lift cylinder 17 is stopped. By returning, the supply and discharge of the hydraulic oil to the elevating cylinder 17 is stopped, and the left and right lift arms 18 are maintained at the swing height position at that time. A is switched to the raised position, and the unload valve unit 19B switches to a discharge stop state that allows the hydraulic oil to flow from the hydraulic pump 20 to the switch valve unit 19A, while the speed adjustment valve unit 19D stops discharging. By self-returning to the position, the supply of hydraulic oil from the hydraulic pump 20 to the lift cylinder 17 via the switching valve portion 19A and the check valve portion 19C is allowed and the left and right lift arms 18 are swung upward and downward. On the contrary, in the lowered state, the switching valve portion 19A is switched to the lowered position, and the unloading valve portion 19B is brought into a discharge state that avoids the flow of hydraulic oil from the hydraulic pump 20 to the switching valve portion 19A. The check valve portion 19C prevents the hydraulic oil from flowing from the lift cylinder 17 to the switching valve portion 19A, while the speed adjustment valve portion 19D allows the hydraulic oil to be discharged from the lift cylinder 17 That it is switched to the discharge position, it is lowered swinging the left and right lift arms 18 to permit the discharge or the like the weight of its own weight or a rotary tiller 7 of the hydraulic oil from the lifting cylinder 17.

  3 is a relief valve portion that holds the hydraulic pressure in the control valve 19 or the like at a set value, and reference numeral 21 reduces the flow rate of the hydraulic oil discharged from the elevating cylinder 17, This is a lowering speed adjustment valve that limits the lowering speed when the left and right lift arms 18 swing downward with the weight of the rotary tiller 7 or the like.

  As shown in FIGS. 3 to 8, the height setting lever 15 can be controlled to move the rotary tiller 7 up and down to a height position corresponding to the operation position in conjunction with the swing operation. The control valve 19 is mechanically linked via an operation linkage mechanism 23 having a one-sided linkage portion 22 that enables a one-piece operation that resists the biasing operation of the control valve 19 toward the lower side. The operation linkage mechanism 23 is mechanically linked to a feedback linkage mechanism 24 that feeds back the operation of the hydraulic operation mechanism 6.

  The one-sided linkage portion 22 is composed of a swinging member that is disposed on the front side of the machine body of the height setting lever 15 so as to be swingable back and forth, and is linked to the height setting lever 15 via an operation link 25. The swing member 22 is fixed to the outer end portion of the rotary shaft 26 that is rotatably installed in the casing 17A of the elevating cylinder 17, and has three elongated holes 22a, 22b, 22c formed on the swing fulcrum side. The link pin 25a of the operation link 25 is inserted and engaged in the long hole 22a formed in the above.

  The rotary shaft 26 is integrally equipped with a first operating arm 27 at its inner end, and the free end of the first operating arm 27 is engaged and linked to one end of a swing link 28 built in the transmission case 3. The swing link 28 is mounted on a linkage arm 29 for operating the switching valve portion 19A and the speed adjustment valve portion 19D of the control valve 19 so as to be able to swing the balance, and the other end portion is connected to the feedback link 30. The free end portion of the second operation arm 31 linked to the lift arm 18 is engaged and linked.

  The linkage arm 29 is linked to the switching valve portion 19A and is connected to the speed adjustment valve portion 19D so as to switch the speed adjustment valve portion 19D to the discharge position in conjunction with the switching operation of the switching valve portion 19A to the lowered position. The spring 32 is pressed and biased by the spring 32 toward the front side of the machine body in the direction of switching the switching valve portion 19A to the lowered position and the direction of switching the speed adjustment valve portion 19D to the discharging position. Normally, the state in which the rear end edge of the long hole 22 a in the swing member 22 contacts the linkage pin 25 a of the operation link 25 is maintained.

  That is, the operation linkage mechanism 23 is configured by the swing member 22, the operation link 25, the rotating shaft 26, the first operation arm 27, the swing link 28, the linkage arm 29, the spring 32, and the like, and the feedback link 30. The feedback operation mechanism 24 is configured by the second operation arm 31 and the like.

  From the above configuration, when the height setting lever 15 is swung toward the rear of the machine body, the rocking member 22 is attached to the spring 32 by the linkage pin 25a of the operation link 25 in conjunction with the rocking. The oscillating operation of the oscillating link 28 to the rear side of the body is performed by the first operating arm 27 using the free end of the second operating arm 31 as a fulcrum while being pulled to the rear side of the body against the force. The linkage arm 29 is displaced to the rear side of the fuselage, and in conjunction with this displacement, the switching valve portion 19A is switched from the neutral position to the raised position, while the speed adjustment valve portion 19D is maintained at the discharge stop position. When the lifted state of the valve 19 appears, the left and right lift arms 18 start to swing upward, and in conjunction with this upward swing, the free end of the first operating arm 27 by the second operating arm 31 is moved. Airframe of swing link 28 as fulcrum The swing operation to the square side is performed.

  That is, while the height setting lever 15 is swung toward the rear of the body, the second operation arm 31 always swings the swing link 28 toward the rear of the body by the first operation arm 27. Is performed prior to the swinging operation of the swing link 28 to the front side of the machine body, and the state in which the linkage arm 29 is displaced from the neutral position to the raised position on the rear side of the machine body is maintained. 19A is switched to the raised position, while the raised state of the control valve 19 that keeps the speed adjusting valve portion 19D at the discharge stop position appears and is maintained, and the lifted swing of the left and right lift arms 18 is continued.

  Thereafter, when the height setting lever 15 is rocked and stopped at an arbitrary operation position, the rocking member 22 is rocked and stopped in conjunction with the stopping operation, and the rocking link by the first operating arm 27 described above. While the swing operation to the rear side of the machine body 28 is stopped, the swing operation of the swing link 28 to the front side of the machine body by the second operation arm 31 described above is continued, whereby the linkage arm 29 is moved to the machine body. When the switching valve portion 19A is switched from the raised position to the neutral position in conjunction with this displacement, the neutral state of the control valve 19 appears and the left and right lift arms 18 are raised. The swing operation is stopped, and in conjunction with the swing stop, the swing operation of the swing link 28 to the front side of the body by the second operation arm 31 is stopped, and the linkage arm 29 is maintained in the neutral position. The neutral of the control valve 19 You state the swing stop state of being emerge holding the left and right lift arms 18 is continued.

  Conversely, when the height setting lever 15 is swung toward the front of the body, the linkage pin 25a of the operation link 25 moves to the front side of the body in conjunction with the swing, and the spring is interlocked with the movement. By the urging of 32, the swinging member 22 swings following the front side of the machine body so as to maintain a state in which the rear end edge of the elongated hole 22a is in contact with the linkage pin 25a of the operation link 25, and the first The operating arm 27 swings the swing link 28 with the free end of the second operating arm 31 as a fulcrum to the front side of the machine body, and the linkage arm 29 is displaced to the front side of the machine body. Thus, the switching valve portion 19A is switched from the neutral position to the lowered position and the speed adjusting valve portion 19D is switched from the discharge stop position to the discharge position, so that the lowered state of the control valve 19 appears and the left and right lift arms 18 are switched. Begins to swing downward, One, in conjunction with the downward swing, swinging operation to the fuselage rear side of the swing links 28 to pivot the free end portion of the first operating arm 27 by the second operating arm 31 is performed.

  That is, while the height setting lever 15 is swung toward the front of the body, the swing operation of the swing link 28 toward the front of the body by the first operation arm 27 is always performed by the second operation arm 31. Is performed prior to the swinging operation of the swing link 28 to the rear side of the body by the above-described operation, and the state in which the linkage arm 29 is displaced from the neutral position to the lowered position on the front side of the body is maintained. The lowered state of the control valve 19 that switches 19A to the lowered position and switches the speed adjusting valve portion 19D to the discharge position is maintained, and the downward swing of the left and right lift arms 18 is continued.

  Thereafter, when the height setting lever 15 is rocked and stopped at an arbitrary operation position, the rocking member 22 is rocked and stopped in conjunction with the stopping operation, and the rocking link by the first operating arm 27 described above. While the swing operation to the front side of the fuselage 28 is stopped, the swing operation to the rear side of the swing link 28 by the second operation arm 31 described above is continued, so that the linkage arm 29 is moved to the fuselage. The neutral position of the control valve 19 is changed by shifting to the neutral position on the rear side, and in conjunction with this displacement, the switching valve portion 19A is switched from the lowered position to the neutral position and the speed adjusting valve portion 19D is switched to the discharge stop position. The state appears and the left and right lift arms 18 stop descending and swinging, and in conjunction with this swinging stop, the swinging link 28 is swung to the rear side of the body by the second operating arm 31 described above. The operation is stopped and 29 by being kept in the neutral position, the neutral state of the control valve 19 is swung stop state of being emerge holding the left and right lift arms 18 is continued.

  In short, when the height setting lever 15 is manually operated to an arbitrary operation position, the left and right lift arms 18 swing up and down to the swing height position corresponding to the operation position of the height setting lever 15, and the rotary Since the tillage device 7 is moved up and down to a height position corresponding to the operation position of the height setting lever 15, the rotary tiller device 7 is positioned at the tillage height position desired by the driver at the start of work. Work can be done easily and appropriately.

  By the way, the swing height position of the left and right lift arms 18 corresponding to the swing operation of the height setting lever 15 to the foremost operation position is a mechanical position lower than the ground contact height at which the rotary tiller 7 performs the tilling work. Thus, for example, when the height setting lever 15 is set to the foremost operation position during tillage work, the left and right lift arms 18 do not descend to the lower limit position. The lowered state of the control valve 19 appears and is maintained, and the left and right lift arms 18 are maintained in a lowered state due to their own weight, the weight of the rotary tiller 7, etc. As a result, the ground reaction force from the work site Accordingly, a so-called floating state in which the rotary tiller 7 automatically moves up and down can appear.

  As shown in FIGS. 4 to 8, the lever guide 33 for operating and guiding the height setting lever 15 is engaged with the height setting lever 15 to swing the height setting lever 15 toward the rear side of the machine body. A stopper 34 is provided as a contact type restricting means for restricting, and this stopper 34 has a knob-attached bolt 34A inserted from above at the rear side of the machine body of the height setting lever 15 in the guide groove 33a of the lever guide 33, and The fixing position can be arbitrarily changed in the operation region on the rear side of the machine body from the height setting lever 15 in the guide groove 33a by the support 34C provided with the welding nut 34B screwed to the bolt 34A with the knob. It is configured.

  That is, the operation limit position of the height setting lever 15 on the rear side of the machine body by the stopper 34, that is, the operation upper limit position of the height setting lever 15 can be set to an arbitrary position by simply operating the bolt 34A with the knob. Since the setting can be changed and the swing upper limit position of the left and right lift arms 18 determined by the operation upper limit position can be easily changed, for example, a specification form in which the protection frame 13 is erected on the boarding operation unit 12 ( 1) and a swing upper limit position of the left and right lift arms 18 corresponding to the upper limit position of the rotary tiller 7, which is changed according to the specification change between the specification form equipped with the cabin 14 (see FIG. 2) and the like. Can easily cope with changes.

  As shown in FIGS. 4 to 9, the swing member 22 is driven to swing in the front-rear direction by the operation of an electric lift motor 35 with a reduction gear, which is an example of an electric actuator provided on the upper rear side of the machine body. The operation arm 36 is linked via a linkage rod 37, and one end portion 37a of the linkage rod 37 is inserted into and engaged with the elongated hole 22b of the swinging member 22. From this linkage configuration, the lifting motor 35 is operated. The swinging member 22 can be swung back and forth by moving the left and right lift arms 18 by switching the operation of the control valve 19 in conjunction with the back-and-forth swinging operation.

  In addition, on the upper front side of the body of the swinging member 22, there is a height composed of a rotary potentiometer which is an example of a height position detecting means for detecting the swinging position of the swinging member 22 as the height position of the rotary tiller 7. A height sensor 38 is provided, and the height sensor 38 is linked to the swinging member 22 by inserting a coupling pin 38a provided at the free end of the detection arm 38A into the elongated hole 22c of the swinging member 22. Has been. The height sensor 38 outputs the detected value to a control device 39 that is a microcomputer that is an example of a control means.

  The swing member 22 is arranged on the upper side in the operation direction with respect to the swing link 28 serving as a link portion between the operation linkage mechanism 23 and the feedback linkage mechanism 24, so that the swing position thereof is a rotary tiller. 7 height position is reflected.

  In addition to the detection value of the height sensor 38, the control device 39 includes detection information of the ascending switch 40 including a limit switch that detects an upward swinging operation of the lifting command lever 16, and swinging the lifting command lever 16 downward. Detection information of the lowering switch 41 comprising a limit switch for detecting a moving operation, from a limit switch for detecting an operation of the forward / reverse switching lever 42 (see FIGS. 1 and 2) provided at the lower left part of the steering wheel 10 to the reverse position. And a rotary potentiometer that is an example of an upper limit position setting means that enables setting change of the swing limit position of the swing member 22 corresponding to the detection information of the reverse switch 43 and the upper limit position of the rotary tiller 7. The set value of the upper limit setter 44 is input, and the control device 39 controls the operation of the lifting motor 35 based on those values and information. That.

  The operation control of the raising / lowering motor 35 by the control device 39 will be described in detail. The control device 39 detects when the raising switch 40 detects the upward swinging operation of the raising / lowering command lever 16, or moves to the reverse position of the forward / reverse switching lever 42. When the reverse switch 43 detects this operation, the forward / lowering operation of the elevating motor 35 is started so that the operation arm 36 is driven to swing to the rear side of the machine body. Then, along with the start of the operation, the one end portion 37a of the linkage rod 37 moves to the rear side of the machine body along the long hole 22b of the swing member 22, and this movement contacts the rear end edge of the long hole 22b. Accordingly, the swinging member 22 is pulled to the rear side of the aircraft against the urging of the spring 32, and by this pulling operation, the height setting lever 15 described above is swinged to the rear side of the aircraft. In the same manner as described above, the lifted state of the control valve 19 appears, and the left and right lift arms 18 start swinging upward, and the lifted state of the control valve 19 appears and is held. The ascending swing is continued.

  After the forward rotation of the lifting motor 35, the swing limit position (the upper limit of the rotary tiller 7) set by the swing member 22 (the rotary tiller 7) by the upper limit setter 44 based on the detection of the height sensor 38. It is determined whether or not the swinging member 22 has reached the swing limit position, and the forward rotation operation of the lifting motor 35 is stopped. Then, the swinging member 22 stops swinging along with the stoppage of the operation, and the neutralization of the control valve 19 is performed in the same manner as when the height setting lever 15 is stopped swinging due to the stop of swinging. The state appears and the left and right lift arms 18 stop rising and swinging. In conjunction with this swinging stop, the neutral state of the control valve 19 appears and is held and the left and right lift arms 18 stop swinging. Will continue.

  On the other hand, when the lowering switch 41 detects the downward swing operation of the lift command lever 16, the reverse rotation operation of the lift motor 35 is started so that the operation arm 36 is driven to swing forward of the machine body, In order to determine whether or not the operation arm 36 has come into contact with the regulation pin 45 on the front side of the machine body due to the operation, it is determined whether or not a preset operation time required for the contact has elapsed. Then, with the start of the operation, the one end portion 37a of the linkage rod 37 moves to the front side of the machine body, and in conjunction with the movement, the swinging member 22 is moved behind the elongated hole 22b by the bias of the spring 32. The front edge of the linkage rod 37 is in contact with the one end 37a of the linkage rod 37 so that the height setting lever 15 is moved to the front side of the machine body. As in the case of the swing operation, the lowering state of the control valve 19 appears and the left and right lift arms 18 start to swing downward, and the lowering state of the control valve 19 appears and is held. The downward swing of the arm 18 is continued.

  In the downward swing of the left and right lift arms 18 by the reverse operation of the lift motor 35, when the rear end edge of the long hole 22a in the swing member 22 contacts the linkage pin 25a of the operation link 25, the height setting lever With the friction holding force of 15, the swinging member 22 is prevented from swinging to the front side of the machine body, and the swinging member 22 stops swinging, and the displacement of the linkage arm 29 linked to the stoppage of swinging to the neutral position. The neutral state of the control valve 19 appears, and the left and right lift arms 18 stop descending and swinging at the set height position set by the height setting lever 15. In this state, the left and right lift arms 18 are kept from swinging and the swinging state of the left and right lift arms 18 is continued. Whether it has passed The operation of the lifting motor 35 is controlled on the basis of this, and if the operation time has not elapsed, the reversing operation of the lifting motor 35 is continued, and the reversing operation of the lifting motor 35 is stopped as the operation time elapses. . Then, by this operation control, the one end portion 37a of the linkage rod 37 moves to the front side of the machine body along the long hole 22b of the swinging member 22 and is separated from the rear end edge of the long hole 22b. Thus, the swinging member 22 is allowed to swing in conjunction with the swinging operation of the height setting lever 15.

  That is, by the control operation of the control device 39 described above, an automatic ascent control that automatically raises the left and right lift arms 18 to a preset swing upper limit position by the operation of the elevating motor 35 or a set height set by the height setting lever 15. The automatic lowering control that automatically lowers to the vertical position can be performed. With this, when the vehicle body is turned around at the end of one step of tilling work, the elevation command lever 16 is swung upward. It is possible to simply raise the rotary tiller 7 to the preset upper limit position, so that the driver can concentrate on the direction change operation during the direction change at the shore, The possibility of the rotary tiller 7 coming into contact with the ridge during the direction change can be avoided, and after the direction change, if the elevation command lever 16 is swung downward, the rotor Tilling to the working height position corresponding to the operating position of the device 7 height setting lever 15 it is possible to easily lowered.

  Further, when it is necessary to reverse the vehicle body, such as when the vehicle body is turned on the coast, it is accompanied by an operation to the reverse position of the forward / reverse switching lever 42 for displaying the reverse state. The rotary tiller 7 can be automatically raised to a preset upper limit position, thereby causing damage to the rotary tiller 7 caused by moving the vehicle body in a state where the rotary tiller 7 is grounded, and rotary tilling. Contact with the rod of the rotary tiller 7 caused by moving the vehicle body backward with the device 7 raised to a low level can be avoided in advance, and then the operation of the forward / reverse switching lever 42 to the reverse position is canceled, If the elevation command lever 16 is swung downward, the rotary tiller 7 can be lowered to a work height position corresponding to the operation position of the height setting lever 15.

  When the rotary tiller 7 is lowered to the work height position corresponding to the operation position of the height setting lever 15 by the downward swing operation of the elevation command lever 16, the swing operation of the height setting lever 15 is performed. By allowing the swinging member 22 to swing based on the above, position control for raising and lowering the rotary tiller 7 to a height position corresponding to the operation position of the height setting lever 15 can be performed.

  In the above-described configuration, the control device 39 executes the automatic ascent control that automatically raises the rotary tiller 7 to the upper limit position and disables the position control by the elevation command lever 16 and the ascent switch 40 or the reverse switch 43. Ascending / descending command means 46 for instructing to the position is constituted, and the raising / lowering command lever 16 and the lowering switch 41 are used to automatically lower the rotary tiller 7 to the set height position set by the height setting lever 15 and A descent command raising / lowering command means 46 for commanding the control device 39 to execute automatic lowering control that enables control is configured.

  As shown in FIGS. 4 to 8, the upper limit setting unit 44 has an operation shaft 44 a linked to the receiving member 34 </ b> C of the stopper 34 via the linkage link 47 and the linkage rod 48, thereby the height setting lever 15. In conjunction with the position change operation of the stopper 34 for setting the upper limit swing position of the left and right lift arms 18 in the position control that appears in the operation of The setting value of the upper limit setting device 44 for setting the value is changed to a value corresponding to the setting position of the stopper 34.

  In other words, the setting operation of the swing upper limit position of the left and right lift arms 18 by the stopper 34 and the operation of setting the swing upper limit position of the left and right lift arms 18 by the upper limit setting device 44 are performed independently. For example, it is possible to avoid forgetting one of the operations that may occur in the vehicle, so that, for example, a specification form (see FIG. 1) in which the protective frame 13 is erected on the boarding operation section 12 (see FIG. 1). ) When changing the specifications, the rotary tillage caused by forgetting the setting change operation by the stopper 34 or the upper limit setter 44 when changing the swing upper limit position of the left and right lift arms 18 according to the change in the specifications. The contact of the rotary tiller 7 with the cabin 14 during the raising operation of the device 7 can be avoided beforehand.

  As shown in FIGS. 4 to 9, the height setting lever 15 has an operation position detected by a lever sensor 49 formed of a rotary potentiometer, which is an example of a lever position detection unit, and the detected value is input to the control device 39. Is done. The control device 39 stores the correlation between the output of the lever sensor 49 and the output of the height sensor 38. When the rotary tiller 7 is lifted by the above-described automatic lift control, the control device 39 has a height at that time. Based on the output of the sensor 38 and the stored correlation between the output of the lever sensor 49 and the output of the height sensor 38, an output target value of the lever sensor 49 corresponding to the output of the height sensor 38 is determined, and When the output value of the lever sensor 49 coincides with this output target value, the automatic lowering control that reversely operates the lifting motor 35 for a preset operating time, as in the case of swinging the lifting command lever 16 downward. Then, the operating arm 36 is brought into contact with the restriction pin 45.

  That is, when the rotary tiller 7 is lifted by the automatic lifting operation, the operator erroneously key-offs the state where the rotary tiller 7 is lifted to the upper limit position by the automatic lift control or during the automatic lift control. Regardless of whether the rotary tiller 7 is stopped while being raised to the upper limit position by turning off the power by performing an operation, etc., the operation position corresponding to the height position of the rotary tiller 7 at that time is reached. By swinging the height setting lever 15, automatic lowering control is performed, and the operation restriction of the swing member 22 by the lifting motor 35 is released. Therefore, position control by operating the height setting lever 15 is possible. Thus, the rotary tiller 7 can be positioned at a height position corresponding to the operation position of the height setting lever 15.

  Incidentally, the operating time for reversely operating the lifting motor 35 in the automatic lowering control is the maximum time (for example, 1 second) required to bring the operating arm 36 into contact with the regulation pin 45 by the reverse rotation of the lifting motor 35. In order to obtain the certainty of operation, a time longer than the maximum time (for example, 1.5 seconds) is set.

  Further, when the operation arm 36 is brought into contact with the restriction pin 45 by the reverse operation of the lifting motor 35, the force that presses the operation arm 36 against the restriction pin 45 by the reverse operation becomes too large. If the force for releasing the operation arm 36 from the restriction pin 45 is increased by the rolling operation, the operation arm 36 may not be released from the restriction pin 45. For the lowering output, a force for pressing the operation arm 36 against the restriction pin 45 by the reverse operation of the lifting motor 35 is made smaller than a force for releasing the operation arm 36 from the restriction pin 45 by the forward rotation operation of the lifting motor 35. A certain output limit is provided, thereby avoiding the possibility that the operation arm 36 cannot be released from the restriction pin 45.

  The time required to bring the operating arm 36 into contact with the regulation pin 45 by the reverse operation of the lifting motor 35 is set by the upper limit setting unit 44 that sets the swing upper limit position of the left and right lift arms 18 in the automatic lifting control. Since this differs depending on the value, the operation time during which the elevating motor 35 is reversely operated in the automatic lowering control may be changed according to the set value of the upper limit setting device 44 in consideration of this point.

  A switch for detecting contact of the operating arm 36 with the regulation pin 45, instead of a configuration in which the lifting motor 35 is reversely rotated for a preset operating time based on a swinging operation of the lifting command lever 16 downward, Alternatively, a switch that detects the arrival of the operation arm 36 at a swing position corresponding to the contact position with the regulation pin 45 without providing the regulation pin 45 is provided, and the elevation command lever 16 is pivoted downward. Based on the operation, the elevating motor 35 may be reversely operated until the switch is detected and operated.

  The lever sensor 49 is arranged so that its operation shaft 49a is located concentrically with the swing fulcrum of the height setting lever 15, and its detection arm 49A is connected to the connecting link 15A fixed to the height setting lever 15. It is connected.

  By the way, the upper limit position of the rotary tiller 7 in the position control is the upper limit position of the mechanical rotary tiller 7 that is obtained when the height setting lever 15 is operated to the operation limit position in contact with the stopper 34. Further, the upper limit position of the rotary tiller 7 in the automatic ascent control is an electric rotary tiller obtained when the lifting motor 35 is operated by the control operation of the controller 39 based on the upward operation of the lifting command lever 16. 7 and the upper limit positions are not related to each other. Therefore, even if the stopper 34 and the upper limit setting unit 44 are merely mechanically linked, the upper limit positions do not coincide with each other.

  Conversely, as described above, when the stopper 34 that is displaced along the lever guide 33 and the upper limit setting device 44 that is a rotary potentiometer are mechanically linked via the linkage link 47 and the linkage rod 48, the stopper The setting change operation of the upper limit setter 44 linked to the position change operation 34 is affected by the operation of the linkage link 47 and the linkage rod 48 that bend and stretch like a hip-fold link in conjunction with the operation of the stopper 34. In addition to the difference between the operation amount of the stopper 34 and the operation amount of the upper limit setting device 44, the difference changes depending on the operation position, and the stopper 34 is moved along the lever guide 33. The obtained output (operation position) of the upper limit setter 44 draws a curve instead of a straight line indicating a proportional relationship with the operation position of the stopper 34. Therefore, not only does the upper limit position in the position control of the rotary tiller 7 and the upper limit position in the automatic ascent control not coincide with each other, but the difference varies depending on the setting of the upper limit position. When the rotary tiller 7 is raised to the upper limit position by either position control or automatic ascent control, the rotary tiller 7 rises more than expected, and the inconvenience of contacting the cabin 14 on the tractor side, etc. There is a risk of inviting.

  In addition, the output of the height sensor 38 compared with the output of the upper limit setting device 44 is obtained when the swinging member 22 is swung from the linkage structure of the swinging member 22 and the height sensor 38 described above. In conjunction with the swing of the swing member 22, the operation position of the swing member 22 is affected by the operation of the detection arm 38A that swings while displacing the linkage pin 38a along the long hole 22c. In this output curve, the link structure of the swing member 22 and the height sensor 38 is different from the link structure of the stopper 34 and the upper limit setting device 44. Therefore, the difference between the output curve of the upper limit setting device 44 and the upper limit position in the position control of the rotary tiller 7 and the upper limit position in the automatic ascent control depends on the setting of the upper limit position. To change more As a result, when the rotary tiller 7 is raised to the upper limit position by either position control or automatic ascent control, the rotary tiller 7 rises more than expected and comes into contact with the cabin 14 on the tractor side. It becomes easy to invite.

  That is, in the above configuration, the stopper 34 and the upper limit setting device 44 having different operation modes are mechanically linked, and the linkage structure is different from the linkage structure in which the swing member 22 and the height sensor 38 are linked. In addition, the constant relationship between the output of the upper limit setter 44 and the output of the height sensor 38 obtained when the stopper 34 and the upper limit setter 44 are not mechanically linked is broken, and this is left as it is. As a result, there is a risk that the rotary tiller 7 rises more than expected and comes into contact with the tractor-side cabin 14 or the like.

  In order to avoid this inconvenience, it is conceivable to configure the linkage structure of the stopper 34 and the upper limit setting device 44 and the linkage structure of the swing member 22 and the height sensor 38 in the same manner. The right side portion of the mission case 3 where the swing member 22 and the height sensor 38 are disposed is a complicated place where the operation linkage mechanism 23, the lifting motor 35, and the like are centrally disposed. Therefore, the stopper 34 and the upper limit setting device In order to secure a space for mounting a linkage structure having the same structure as the linkage structure that mechanically links the motor 44 to the machine 44, a large-scale improvement is required to change the configuration of the operation linkage mechanism 23, the arrangement of the lifting motor 35, and the like. become.

  And in order to avoid the large-scale improvement, the proportional relationship is established between the operation position of the stopper 34 and the operation position of the upper limit setting device 44, or the output of the upper limit setting device 44 while adopting a different linkage structure. It is conceivable that a proportional relationship is established between the height sensor 38 and the output of the height sensor 38, but in order to establish the former proportional relationship, in the linkage structure in which the stopper 34 and the upper limit setter 44 are mechanically linked, each part It is necessary to provide an adjustment mechanism or the like that enables adjustment of the operation of the motor, and in order to establish the latter proportional relationship, a linkage structure in which the stopper 34 and the upper limit setting device 44 are mechanically linked, or a height sensor 38. In the linkage structure that mechanically links the swing member 22 and the swinging member 22, it is necessary to provide an adjustment mechanism or the like that enables adjustment of the operation of each part. Assembling for work is reduced.

  Therefore, the output of the upper limit setter 44 that detects the operation position of the stopper 34 by being mechanically linked to the stopper 34 and the height that detects the swing position of the swing member 22 as the height position of the rotary tiller 7. A correlation with the output of the height sensor 38 is stored in the control device 39, and the control device 39 corresponds to the output of the upper limit setting device 44 based on the relative relationship and the output of the upper limit setting device 44. In the automatic elevation control, the operation of the lifting motor 35 is controlled until the output value of the height sensor 38 matches the determined output target value.

  According to this configuration, the operation of the upper limit setter 44 that is linked to the position change operation of the stopper 34 is affected by the operation of the linkage link 47 and the linkage rod 48 that convert the operation of the stopper 34 to the operation of the upper limit setter 44. Thus, the output (operating position) of the upper limit setter 44 obtained when the stopper 34 is moved along the lever guide 33 draws a curve instead of a straight line indicating a proportional relationship with the operating position of the stopper 34. Further, the swing operation of the swing member 22 is converted into the detection operation of the height sensor 38, and the swing operation of the swing member 22 is converted into the detection operation of the height sensor 38. The output of the height sensor 38 obtained when the swinging member 22 swings as the rotary tiller 7 moves up and down is affected by the operation of the detection arm 38A. Even if a curved line is drawn instead of a straight line indicating the proportional relationship, the operation of the elevating motor 35 can be controlled in consideration of the influence thereof, and as a result, the height setting lever 15 is provided on the stopper 34. A control device that controls the operation of the elevating motor 35 based on the upper limit position of the rotary tiller 7 in the position control that appears upon contact, the output of the upper limit setter 44, and the output of the height sensor 38. It is possible to match the upper limit position of the rotary tiller 7 in the automatic ascent control that appears in the control operation 39.

  As a result, it is possible to improve the operability and reliability when changing the upper limit position of the work device 7 according to the additional equipment of the cabin 14 or the replacement of another work device 7 of the rotary tiller 7 and the like. Contact with the cabin 14 on the vehicle body side of the work apparatus 7 due to the difference between the upper limit position in the position control of the work apparatus 7 and the upper limit position in the automatic ascent control can be avoided.

  Then, by matching the upper limit position of the rotary tiller 7 in the position control with the upper limit position of the rotary tiller 7 in the automatic raising control, regardless of the setting change of the upper limit position, the rotary tiller 7 in the automatic raising control When the tilling device 7 is raised to the upper limit position, the control device 39 determines the correlation between the output value of the height sensor 38 at this time and the output of the stored height sensor 38 and the output of the lever sensor 49. The target output value of the lever sensor 49 is determined based on the above, and if the height setting lever 15 is operated in this state, the output value of the lever sensor 49 is automatically updated until the output target value matches the target output value. If the position control cannot be performed without the lowering control, and the output value of the lever sensor 49 matches the output target value, the automatic lowering control is performed and the position control is possible. Even if the output value of the lever sensor 49 matches the output target value, the rotary tiller 7 does not move up and down unless the height setting lever 15 is operated from the operation position at that time. When the height setting lever 15 is operated from the operation position, the rotary tiller 7 moves up and down to a height position corresponding to the operation position of the height setting lever 15.

  With the above configuration, it is possible to improve the operability and certainty when changing the upper limit position of the working device 7 according to the additional equipment of the cabin 14 or the replacement of the working device 7 and the position of the working device 7. The upper limit of the working device 7 can be avoided while avoiding contact with the cabin 14 on the vehicle body side of the working device 7 due to the difference between the upper limit position in the control and the upper limit position in the automatic ascent control. Regardless of the position setting change, when the position control is enabled by operating the height setting lever 15 after performing the automatic ascent control, the work device 7 is inadvertently raised or lowered, or erroneously during the automatic ascent control. Thus, it is possible to avoid the raising / lowering failure of the working device 7 that occurs when the working device 7 is raised and stopped.

  By the way, the correlation between the output of the upper limit setting device 44 and the output of the height sensor 38 is, for example, that the height setting lever 15 and the stopper 34 operated in the operation region of the height setting lever 15 are connected to the height setting lever. It is conceivable that a sampled value is obtained from the output of the upper limit setter 44 and the height sensor 38 obtained when moving in the same direction and at the same speed in the 15 operation areas.

  Further, the correlation between the output of the height sensor 38 and the output of the lever sensor 49 is, for example, the output of the lever sensor 49 obtained when the height setting lever 15 is operated over the entire operation region, and the output at that time. It is conceivable that a sampled value is acquired and established from the output of the height sensor 38 that detects the height position of the rotary tiller 7 that moves up and down in conjunction with the operation of the height setting lever 15.

  That is, each of the upper limit setting device 44, the height sensor 38, and the lever sensor 49 obtained when the height setting lever 15 and the stopper 34 are moved in the same direction in the operation region of the height setting lever 15 at the same speed. From the output, the correlation between the output of the upper limit setter 44 and the output of the height sensor 38 and the correlation between the output of the height sensor 38 and the output of the lever sensor 49 can be established simultaneously.

  Specifically, in the state where the control mode of the control device 39 is switched from the normal mode to the adjustment mode, which is an example of the special mode, the height setting lever 15 is loosened with the knob-attached bolt 34A to enable the position changing operation. The height setting lever 15 is moved along the guide groove 33a of the lever guide 33 from its foremost position (end position in the descending direction) to the last position ( When the control device 39 is swung all at once, the output value of the height sensor 38, the output value of the upper limit setter 44, and the output value of the lever sensor 49, which change in accordance with the operation, are moved. Are sampled at predetermined time intervals and stored in a non-volatile memory (not shown), the correlation between the output of the height sensor 38 and the output of the upper limit setting unit 44, and the height sensor 38 It is configured to establish the correlation between the output of the force and the lever sensor 49.

  Incidentally, the correlation between the output of the height sensor 38 and the output of the upper limit setter 44 stored in the control device 39 and the correlation between the output of the height sensor 38 and the output of the lever sensor 49 were sampled. A value or a relative relational expression obtained from the sampled value is conceivable, and the number of sampling values stored in the nonvolatile memory is the height sensor 38 obtained by the above operation when establishing the correlation. According to the similarity between the output (output line) and the output (output line) of the upper limit setter 44, and the similarity between the output (output line) of the height sensor 38 and the output (output line) of the lever sensor 49. Various changes can be made from one to many.

  For example, when the similarity is high such that the output line of the height sensor 38 and the output line of the upper limit setter 44 obtained by the above operation when establishing the correlation are the same shape and only the level is different. It is possible to establish a correlation between the output of the height sensor 38 and the output of the upper limit setter 44 by storing one sampling data necessary for matching the levels in the nonvolatile memory of the control device 39. Also, the output line of the height sensor 38 and the output line of the upper limit setter 44 are similar to each other, or a certain relationship is established between the output line of the upper limit setter 44 and the output line of the lever sensor 49. Thus, when the similarity is relatively high, the relative relational expression obtained from a plurality of sampling data is stored in the nonvolatile memory of the control device 39, so that the output of the height sensor 38 and the upper It is possible to establish a correlation with the output of the setter 44 and a correlation between the output of the upper limit setter 44 and the output of the lever sensor 49, and the output line of the height sensor 38 and the upper limit setter When the output line of 44 or the output line of the upper limit setter 44 and the output line of the lever sensor 49 are completely different, the control device is used to control a plurality of sampling data obtained by fine sampling. 39, the correlation between the output of the height sensor 38 and the output of the upper limit setter 44 and the correlation between the output of the upper limit setter 44 and the output of the lever sensor 49 are established. It is possible.

  As shown in FIG. 9, command information from a backup switch 51, a drive changeover switch 52, a rolling switch 53, and the like provided in the boarding operation unit 12 is input to the control device 39. The rotary tiller 7 is automatically raised to the upper limit position set by the upper limit setter 44 based on the detection of the reverse switch 43, and the drive changeover switch is switched. On the basis of the command information from 52, the front wheel clutch (not shown) provided in the transmission case 3 is switched to change the driving state so that the left and right front wheels 4 and the left and right rear wheels 5 are driven. Switching between a driving state and a two-wheel driving state in which only the left and right rear wheels 5 are driven, and further based on command information from the rolling switch 53. Then, based on the detection of a tilt sensor (not shown) for detecting the right and left tilt angle of the tractor 1, the hydraulic rolling cylinder (not shown) is operated so that the rotary tiller 7 is maintained in a horizontal posture. And a state in which the operation of the rolling cylinder is controlled so that the rotary tiller 7 is maintained in a preset right / left inclined posture.

  The control device 39 switches the control mode to be executed between the normal mode and the adjustment mode based on the command information when the backup switch 51 and the rolling switch 53 are operated simultaneously, and executes the control mode based on the command information. In the state of switching to the adjustment mode, when the upward movement of the up / down command lever 16 is detected by the ascending switch 40, while the detection continues, that is, the up / down command lever 16 is swung upward. When the raising / lowering motor 35 is normally rotated only while the moving operation is continued, and when the downward movement of the raising / lowering command lever 16 is detected by the lowering switch 41, the detection is continued. That is, the lift motor 35 is configured to rotate reversely only while the downward movement of the lift command lever 16 is continued.

  That is, the mode switch 54 is constituted by the backup switch 51 and the rolling switch 53, and the up / down swinging operation of the lift command lever 16 in a state where the control mode of the control device 39 is switched to the adjustment mode by the operation of the mode switch 54. Therefore, the lifting / lowering motor 35 can be inching-operated, and this requires a troublesome work such as connecting the lifting / lowering motor 35 directly to the battery for a slight positional shift when the lifting / lowering motor 35 is linked to the swing member 22 or the like. Can be easily adjusted, and the assembling workability of the lifting operation system can be improved. When the left and right lift arms 18 do not swing up and down regardless of the up / down swinging operation of the lift command lever 16, the lift switch 40 is moved upward to the lift command lever 16 in the state switched to the adjustment mode. While detecting the swinging operation and while the lowering switch 41 detects the swinging operation of the lowering of the lift command lever 16, it is confirmed whether or not the current is flowing, thereby raising and lowering the motor 35. It becomes easy to investigate the cause of the failure of the lifting motor 35 and the hydraulic system or the control device 39 thereafter.

  The configuration of the mode switching means 54 is not limited to the above configuration as long as it is a combination that is not normally operated simultaneously. For example, the combination of the backup switch 51 and the drive switch 52, 52 and a rolling switch 53, or a combination of a backup switch 51 and a key switch (not shown). When the control mode of the control device 39 is switched to the adjustment mode, the execution of the adjustment mode is notified by display means (not shown) such as a liquid crystal panel or an indicator lamp provided in the boarding operation unit 12. ing.

  In addition, when the height sensor 38 or the upper limit setter 44 is faulty or the like, and when it becomes impossible to perform automatic ascent control for automatically raising the rotary tiller 7 to the upper limit position set by the upper limit setter 44, the height at the time of failure Based on the output of the sensor 38 and the upper limit setter 44, the control operation of the control device 39 based on the detection of the up switch 40 is performed while the up switch 40 detects the upward swinging operation of the up / down command lever 16. However, it may be configured to automatically switch to a control operation in which the elevating motor 35 is normally rotated and the left and right lift arms 18 are moved up and down.

  On the other hand, in the normal mode, when a simultaneous operation of the backup switch 51 and the drive changeover switch 52 is performed, which is not normally performed, the lift motor 35 is normally rotated only while the operation is continued, and the left and right lifts are operated. When the arm 18 is moved up and down, and the simultaneous operation of the drive switch 52 and the rolling switch 53, for example, which is not normally performed, is performed, the lift motor 35 is reversely operated only while the operation is continued. The control operation of the control device 39 with respect to the lifting motor 35 is switched to a state in which the left and right lift arms 18 are swung downward, whereby the lifting motor 35 is operated by operating the ascending switch 40 or the descending switch 41. While making it easier to investigate the cause of the malfunction, the lowering switch 41 and the upper limit setting device 44 or Lowering operation of the interference in the left and right lift arms 18 of the link rod 37 relative to the swinging member 22 which is reversed impossible attributed the elevation motor 35 due to failure of Sensa 49 is adapted to be prevented from becoming impossible at all.

  In this configuration, the backup switch 51, the drive changeover switch 52, and the rolling switch 53 function as command means.

[Another embodiment]
Hereinafter, other embodiments of the present invention will be listed.
[1] As a work vehicle, a riding type rice transplanter equipped with a seedling planting device that is an example of the work device 7 so as to be movable up and down, and a seeding device that is an example of the work device 7 as a work equipment that is connected and equipped so as to be capable of raising and lowering. It may be a riding seeder.

[2] The work device 7 may be a wrinkle coating device, a scraping device, a medicine spraying device, or the like.

[3] The control valve 19 can be variously modified. For example, the switching valve portion 19A, the unload valve portion 19B, the check valve portion 19C, the speed adjustment valve portion 19D, and the relief valve portion 19E are independent. It may be formed.

[4] The hydraulic operation mechanism 6 may be composed of a hydraulic single-acting lifting cylinder 17 equipped to swing the link mechanism 8 in the vertical direction. Instead of the cylinder 17, a hydraulic lifting motor or the like may be provided.

[5] The lift command means 46 includes a lift command lever 16 and a multi-contact switch, a lift button type lift switch and a push button type drop switch, or a lift command. As the lift command means 46, there may be provided a switch or the like for detecting the appearance of the reverse state in the forward / reverse switching device.

[6] An electric lift cylinder or the like may be employed as the electric actuator 35.

[7] The height setting lever 15 is an engagement holding type in which the lever guide 33 is held at an arbitrary operation position by engagement with a plurality of engagement notches aligned with one side edge of the guide groove 33a. It may be configured.

[8] The one-sided linkage portion 22 may be disposed on the lower side in the operation direction than the swing link 28 that is a linkage portion between the operation linkage mechanism 23 and the feedback linkage mechanism 24.

[9] The height position detecting means 38 detects, for example, the swing position of the operation arm 36 that is driven to swing back and forth by the operation of the lifting motor 35 as the height position of the rotary tiller 7. Alternatively, the swing position of the left and right lift arms 18 may be detected as the height position of the rotary tiller 7.

Overall side view of a protective frame tractor Overall side view of cabin tractor Diagram showing the hydraulic configuration of the lifting operation structure Side view of the main part showing the linkage structure of the lifting operation structure Side view of the main part showing the state where the height setting lever is set to an arbitrary operation position Side view of the main part showing the state where the height setting lever is in contact with the contact-type limiting means Side view of main part showing contact operation state of height setting lever and contact type restricting means Front view of the main part showing the configuration of the contact-type limiting means Block diagram showing control configuration

Explanation of symbols

DESCRIPTION OF SYMBOLS 6 Hydraulic type operating mechanism 7 Working device 15 Height setting lever 19 Control valve 22 Per contact type linkage part 23 Operating linkage mechanism 24 Feedback linkage mechanism 34 Contacting type restricting means 35 Electric actuator 38 Height position detecting means 39 Control means 44 Upper limit position setting means 46 Elevation command means 49 Lever position detection means 51 Command means 52 Command means 53 Command means 54 Mode switching means

Claims (5)

In conjunction with the operation of the height setting lever, the height setting lever is moved to the height position corresponding to the operation position of the height setting lever, and the height setting lever is moved to the working device. A control valve that controls the operation of the hydraulic operation mechanism that moves up and down is provided with an operation linkage mechanism that includes a one-sided linkage portion that enables one-piece operation against the biasing of the control valve to the lowering side. And mechanically link a feedback linkage mechanism that feeds back the operation of the hydraulic operation mechanism to the operation linkage mechanism.
Based on the ascending command operation of the ascending / descending command means, an automatic ascending control for automatically raising the working device to a preset upper limit position and disabling the position control is performed, and the descending command operation of the ascending / descending command means is performed. Based on this, an electric actuator is mechanically attached to the one-sided linkage portion so that the automatic lowering control that allows the position control can be performed while the working device is automatically lowered to the height position set by the height setting lever. A working vehicle lifting and lowering operation structure comprising control means for controlling the operation of the electric actuator based on the operation of the lifting and lowering commanding means,
Lever position detecting means for detecting the operation position of the height setting lever, and height position detecting means for detecting the height position of the working device,
In the control means, the correlation between the output of the lever position detection means and the output of the height position detection means is stored,
The control means determines an output target value of the lever position detection means corresponding to the output of the height position detection means on the basis of the output of the height position detection means and the correlation, and this output A lifting / lowering operation structure for a work vehicle configured to perform the automatic lowering control when an output value of the lever position detecting means coincides with a target value. Equipped with a contact type limiting means for limiting the operation of the height setting lever in the ascending direction by contact with the height setting lever so that the position can be changed,
An upper limit position setting means for enabling the setting change of the upper limit position in the automatic ascent control,
The contact type limiting means and the upper limit position setting means are mechanically linked so that the setting change operation of the upper limit position setting means is performed in conjunction with the position change operation of the contact type restriction means,
In the control means, the correlation between the output of the upper limit position setting means and the output of the height position detection means is stored,
The control means corresponds to the output of the upper limit position setting means based on the output of the upper limit position setting means and the correlation between the output of the upper limit position setting means and the output of the height position detection means. The output target value of the height position detecting means is determined, and the automatic elevation control controls the operation of the electric actuator until the output value of the height position detecting means matches the determined output target value. The lifting / lowering operation structure for a work vehicle according to claim 1, which is configured as follows. A normal mode in which the control means performs the automatic ascent control based on an ascending command from the ascending / descending command means, and performs the automatic descending control based on a descending command from the ascending / descending command means; and the ascending / descending command means On the basis of the ascending command from, manual ascending control is performed to raise the work device by operating the electric actuator while the ascending command is continuously input, and based on the descending command from the ascending / descending command means A special mode for performing manual lowering control for lowering the working device by operating the electric actuator while the lowering command is continuously input,
The work vehicle lifting / lowering operation structure according to claim 1, further comprising mode switching means for instructing the control means to switch a control mode to be executed.   When the plurality of existing command means are operated simultaneously, the control means operates the electric actuator to raise the work device while the commands from the command means are continuously input. And when a plurality of existing command means different from the combination for performing the manual ascent control are operated simultaneously, the electric actuator is operated while the commands from these command means are continuously input. The lifting / lowering operation structure for a work vehicle according to any one of claims 1 to 3, wherein the lifting / lowering operation structure is configured to perform manual lowering control to operate and lower the working device.   5. The work vehicle according to claim 1, wherein the automatic lowering control is configured such that the electric actuator is operated only for a predetermined time by a control operation of the control means. Elevating operation structure.

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