JP4326496B2 - 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 the above-mentioned lifting / lowering operation structure of the work vehicle, the operation limit position of the height setting lever by a lever guide or the like for operating and guiding the height setting lever is set as the upper limit position of the working device in the position control, There is one in which a restriction position where the motor arm is restricted by a rise restriction stopper is used as an upper limit position of the working device in automatic raising control (for example, see Patent Document 1).
JP 2003-333902 A

  That is, in the above conventional configuration, the upper limit position of the work device cannot be changed in either position control or automatic ascent control.

  Therefore, when the work vehicle is additionally equipped with a cabin to improve the work environment, or when the work device is replaced for performing other work, the work device is inadvertently raised to the upper limit position. There is a possibility that the working device may come into contact with the cabin or the like on the work vehicle side and damage them.

  Therefore, a stopper that restricts the operation of the height setting lever in the upward direction by contact with the height setting lever is equipped with a lever guide that guides the operation of the height setting lever so that the position can be changed. The height position of the work device corresponding to the operation limit position of the set height setting lever is set as the upper limit position of the work device in position control, and the setting of the upper limit position can be changed in automatic lift control of the work device. Equipped with an upper limit setter and a height sensor for detecting the height position of the work device, the height position of the work device detected by the height sensor at the upper limit position set by the control means with the upper limit setter It is configured to control the operation of the electric motor so that it matches, and the height position of the work device obtained by the control operation is set as the upper limit position of the work device with automatic climbing control, so additional equipment of the cabin And work equipment It is possible to change the setting of the upper limit position corresponding to the replacement, etc., but in this configuration, when changing the setting of the upper limit position of the work device, the position change operation of the stopper and the setting change operation of the upper limit setting device Therefore, there is room for improvement in making it easy to change the setting of the upper limit position, and if one of the settings is neglected, it will be based on the setting on the neglected side. When the working device is raised to the upper limit position, there is a risk that the working device may come into contact with the cabin or the like on the work vehicle side.

  The object of the present invention is to easily and surely set the upper limit of the work device according to the additional equipment of the cabin, etc., and to operate the work device by the raising operation to the upper limit position regardless of the position control and the automatic raising control. The object is to avoid the possibility of contact with the vehicle side.

  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. In a lifting / lowering operation structure for a work vehicle that includes a control unit that mechanically links the actuator and controls the operation of the electric actuator based on the operation of the lifting / lowering command unit, the height is determined by contact with the height setting lever. A contact-type limiting means for limiting the operation of the setting lever in the upward direction is equipped so that the position can be changed, and an upper limit position setting means for enabling the setting change of the upper limit position in the automatic upward control, A height position detecting means for detecting a height position, wherein the contact type restricting means and the upper limit position setting means are interlocked with a position change operation of the contact type restricting means. It is mechanically linked so that the setting change operation of the upper limit position setting means is performed, the correlation between the output of the upper limit position setting means and the output of the height position detection means is stored in the control means, and the control means However, based on the output of the upper limit position setting means and the correlation, the output target value of the height position detection means corresponding to the output of the upper limit position setting means is determined, and in the automatic elevation control, The operation of the electric actuator is controlled until the output value of the height position detecting means matches the determined output target value.

  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, the upper limit position in the position control of the work device and the upper limit position in the automatic lift control can be set and changed all at once by simply performing the position change operation of the contact type restricting means. Compared to when the upper limit position for control and the upper limit position for automatic ascending control are individually set and changed, it is easier to change the setting of the upper limit position and forget to change the setting of one of the upper limit positions. This can be avoided beforehand.

  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. According to this configuration, the operation of the upper limit position setting unit linked to the contact type limiting unit is converted into the operation of the upper limit position setting unit. Influence of linkage mechanism The operation of the linkage mechanism that converts the raising / lowering operation of the working device into the detecting operation (operation) of the height position detecting device influences the detection operation of the height position detecting means interlocked with the raising / lowering of the working device. Even in such a case, it is possible to control the operation of the electric actuator in consideration of those influences. As a result, the position that appears when the height setting lever is brought into contact with the contact-type limiting means In the 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 in the control, the output of the upper limit position setting means and the output of the height position detection means The upper limit position of the working device can be matched.

  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. Contact with the cabin or the like on the vehicle body side of the working device due to the difference between the upper limit position and the upper limit position in the ascent control can be avoided.

  According to a second aspect of the present invention, in the first aspect of the present invention, the one-piece type linkage portion is operated more than the linkage portion between the operation linkage mechanism and the feedback linkage mechanism. It is arranged on the upper side in the direction, and the height position detecting means is configured to detect the operation position of the one-sided linkage part.

  In this configuration, because of the structure that enables position control to raise and lower the work device to a height position corresponding to the operation position of the height setting lever, the one-sided linkage portion is connected to the operation linkage mechanism and the feedback linkage mechanism. If it is arranged on the upper side in the operation direction than the linkage part, the height position of the work device is reflected as the operation position of the one-sided linkage part, and the height position detecting means operates the one-sided linkage part. The position is detected as the height position detection means, and as a result, when obtaining the correlation between the output of the upper limit position setting means and the output of the height position detection means, the hydraulic system such as the hydraulic operation mechanism is operated. Further, it is possible to obtain a correlation between the output of the upper limit position setting means and the output of the height position detection means from the stage before the assembly of the hydraulic operation mechanism or the like.

  Therefore, it is possible to improve the workability when obtaining the correlation between the output of the upper limit position setting means and the output of the height position detection means.

  In the invention according to claim 3 of the present invention, in the invention according to claim 1 or 2, provided with a lever position detection means for detecting the operation position of the height setting lever, the control means, The correlation between the output of the upper limit position setting means and the output of the lever position detection means is stored, and the control means outputs the output of the upper limit position setting means, the output of the upper limit position setting means, and the lever position detection means. And an output target value of the lever position detecting means corresponding to the output of the upper limit position setting means, and the output value of the lever position detecting means is the output target value. The automatic lowering control is performed when they match.

  According to this configuration, the output of the upper limit position setting unit that detects the operation position of the contact type limiting unit by being mechanically linked to the contact type limiting unit is determined by the operation position of the contact type limiting unit. Since it is also the operation limit position of the height setting lever, if the output of the upper limit position setting means is compared with the output of the lever position detection means that detects the operation position of the height setting lever, the result is the contact type. It is possible to determine whether or not the height setting lever is in contact with the restricting means.

  However, as described above, the output of the upper limit position setting means is set to the upper limit position in the operation (detection operation) by the mechanical linkage with the contact type restriction means having different operation forms. Not only will there be a difference between the operation amount of the linkage mechanism and the operation amount of the contact type limiting means, but also the difference between the operation amount and the operation amount of the contact type limiting means. The output (detection position) with respect to the position change operation of the contact type restricting means draws a curve instead of a straight line indicating a proportional relationship with the operation position of the contact type restricting means. Therefore, the output of the upper limit position setting means and the output of the lever position detection means are simply compared without considering the relationship between the operation position of the contact type limiting means and the output of the upper limit position setting means. Even if the height setting lever is brought into contact with the contact-type restricting means, the control means makes the contact with the contact-type restricting means from the output of the upper limit position setting means and the output of the lever position detecting means at that time. When it is not determined that the height setting lever has been touched, the automatic lowering control is not performed and position control cannot be performed, or the stage before the height setting lever touches the contact-type limiting means The automatic lowering control is performed when the control means determines that the height setting lever is in contact with the contact-type limiting means based on the output of the upper limit position setting means and the output of the lever position detection means at that time. Then, position control becomes possible, and there is a risk of inconvenience that the working device rises unexpectedly in conjunction with the subsequent operation until the height setting lever contacts the contact-type limiting means.

  In order to avoid these inconveniences, it is conceivable to link the height setting lever and the lever position detecting means so that the output of the lever position detecting means draws the same curve as the output of the upper limit position setting means. However, in order to do so, it is necessary to provide an adjustment mechanism or the like that enables adjustment of the operation of each part in the linkage mechanism, resulting in a complicated structure and a decrease in assembly performance due to the adjustment work. It will be.

  Therefore, the correlation between the output of the upper limit position setting means that detects the operation limit position of the height setting lever as a result of mechanical linkage with the contact type restriction means and the output of the lever position detection means is used as the control means. Based on the correlation and the output of the upper limit position setting means, the control means determines an output target value of the lever position detection means corresponding to the output of the upper limit position setting means, and the lever position is determined based on this output target value. The automatic lowering control is performed when the output values of the detection means coincide with each other. According to this configuration, the operation of the upper limit position setting means in conjunction with the contact type restriction means is limited to the contact type. The operation of the height setting lever is applied not only to the operation of the linkage mechanism that converts the operation of the means to the operation of the upper limit position setting means but also to the detection operation of the lever position detection means linked to the operation of the height setting lever. Lever position Even if the operation of the linkage mechanism that converts to the detection operation of the detection means has an effect, the lever position is added to the output value of the upper limit position setting means (the output target value of the lever position detection means) in consideration of those effects. It is possible to accurately determine whether or not the output values of the detection means match (whether or not the height setting lever has come into contact with the contact-type limiting means). Even if it comes into contact with the restricting means, the control means does not determine that the height setting lever has contacted the contact type restricting means, and the automatic lowering control is not performed, so that the position control remains impossible. From the stage before the height setting lever contacts the contact-type limiting means, the control means determines that the height setting lever has contacted the contact-type limiting means and performs automatic lowering control. Position control becomes possible. Unfortunately the work device setting lever interlocked with the operations up to brought into contact with abutment formula limiting means increases unexpectedly, the occurrence of possible avoided in advance.

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

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

  In short, lever position detection determined based on the output value of the upper limit position setting means when the height setting lever is brought into contact with the contact type restricting means in the state where the work device is automatically raised to the upper limit position by the automatic ascent control. Since the output value of the lever position detecting means coincides with the output target value of the means, the control means can accurately detect that the height setting lever has reached the operation limit position by the contact type restricting means. Based on this detection, the control means performs automatic lowering control, so that position control is possible, and thus the working device can be positioned at a height position corresponding to the operation position of the height setting lever.

  As a result, after performing automatic ascent control to automatically raise the working device to the upper limit position, a height different from the height position (working height position) of the working device corresponding to the current operation position of the height setting lever. If you want to position the work device at a position (for example, a height position where maintenance can be easily performed), perform the operation to perform automatic lowering control first, and move the work device to the current position of the height setting lever. After automatically lowering to the corresponding height position and enabling position control, operate the height setting lever to perform position control to raise and lower the work device to the height position corresponding to the operation position. Even if the operation procedure is not performed, position control can be performed only by operating the height setting lever, and the work device can be positioned at an arbitrary height position.

  Therefore, it is possible to improve the elevating operability so that an arbitrary operation to the maintenance position after the work device is automatically raised to the upper limit position by the automatic raising control can be easily and reliably performed.

  In the invention according to claim 4 of the present invention, in the invention according to claim 1 or 2, the contact of the height setting lever with respect to the contact type restricting means is applied to the contact type restricting means. A switch for detecting is provided, and the control means performs the automatic lowering control based on an output when the switch detects the contact.

  According to this configuration, when the automatic elevation control is activated and the work device is located at the upper limit position, when the height setting lever is brought into contact with the contact-type limiting means, the contact is detected by the switch. Then, the automatic lowering control is revealed by the control operation of the control means based on the detection, and the position control can be manifested, so that the working device is positioned at the height position corresponding to the operation position of the height setting lever. be able to.

  In other words, after the automatic ascent control is displayed and the working device is raised to the upper limit position, the height position is different from the height position (working height position) of the working device corresponding to the current operation position of the height setting lever. If you want to position the work device (for example, at a height where maintenance is easy to perform), perform the operation to perform the automatic lowering control first, so that the work device corresponds to the current height setting lever operation position. Automatically lowering to the height position to be performed and enabling position control, then operating the height setting lever to perform position control to raise and lower the work device to the height position corresponding to the operation position, etc. Even if the operation procedure is not performed, position control can be performed only by operating the height setting lever, and the work device can be positioned at an arbitrary height position.

  In addition, it is an inexpensive construction that only has a switch on the contact-type limiting means, and this switch always moves integrally with the contact-type limiting means whose position is changed, and the height is set in the contact-type limiting means. When the lever contacts, regardless of the change of the position of the contact type limiting means, the contact is detected directly and reliably, so the output of the upper limit position setting means and the lever position detection means There is no need to take a correlation between the output of the upper limit position setting means and the output of the lever position detection means as in the case of determining the contact of the height setting lever with the contact type restriction means from the output.

  Therefore, the maintenance position after automatically raising the work device to the upper limit position with automatic elevation control while reducing the cost and labor required to determine the contact of the height setting lever with the contact type limiting means It is possible to improve the elevating operability so that an arbitrary operation can be easily and reliably performed.

  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. Then, when the left and right lift arms 18 have reached the swing upper limit position by the automatic ascent control described above, the control device 39 detects the operation position of the height setting lever 15 detected by the lever sensor 49 and the upper limit setting. On the basis of the set position of the stopper 34 detected from the set value of the device 44, it is determined whether or not the height setting lever 15 has reached the operation upper limit position contacting the stopper 34, and the height setting lever 15 is operated. When it is determined that the upper limit position has been reached (when the detection value of the lever sensor 49 corresponds to the setting value of the upper limit setting device 44), the elevation command lever 16 is swung downward, and As in, by revealing the auto down control for reversing operation of the lifting motor 35 by actuating preset time, thereby Setto the operating arm 36 to the regulating pin 45.

  In other words, when the left and right lift arms 18 have reached the swing upper limit position by the automatic raising operation, the height setting lever 15 is swung to the operation upper limit position contacting the stopper 34 to automatically descend. Since the control is released and the operation restriction of the swing member 22 by the lifting motor 35 is released, the position control by the operation of the height setting lever 15 becomes possible, and the rotary tiller 7 is operated by the operation of the height setting lever 15. It can be located at a height position corresponding to the position.

  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.

  By the way, 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 is also the operation limit position of the height setting lever 15 determined by the operation position of the stopper 34. If the output of the upper limit setter 44 is compared with the output of the lever sensor 49 that detects the operation position of the height setting lever 15, whether or not the height setting lever 15 has come into contact with the stopper 34 based on the result. Can be determined.

  However, as described above, the output of the upper limit setter 44 is mechanically linked to the stopper 34 having a different operation form, and the operation (detection operation) of the upper limit setter 44 is operated in the operation (detection operation). The operation of the interlocking link 47 and the interlocking rod 48 converted into () is affected, and not only does the operation amount of the stopper 34 and the operation amount of the stopper 34 differ, but the difference changes depending on the operation position. The output (detection position) with respect to the position change operation of the stopper 34 is not a straight line indicating a proportional relationship with the operation position of the stopper 34 but a curve, and therefore, the operation position and upper limit setting of the stopper 34 are set. By simply comparing the output of the upper limit setting device 44 and the output of the lever sensor 49 without considering the relationship with the output of the device 44, the height setting lever 1 Even if the stopper 34 is brought into contact with the stopper 34, the control device 39 does not determine that the height setting lever 15 has come into contact with the stopper 34 from the output of the upper limit setting device 44 and the output of the lever sensor 49 at that time. Thus, the inconvenience that the automatic lowering control is not performed and the position control cannot be performed, or before the height setting lever 15 contacts the stopper 34, the output of the upper limit setter 44 and the lever at that time When the control device 39 determines from the output of the sensor 49 that the height setting lever 15 is in contact with the stopper 34, automatic lowering control is performed and position control becomes possible. There is a risk that the rotary tiller 7 will rise unexpectedly in conjunction with the operation until the height setting lever 15 contacts.

  In order to avoid these inconveniences, it is conceivable to link the height setting lever 15 and the lever sensor 49 so that the output of the lever sensor 49 draws the same curve as the output of the upper limit setting device 44. In order to do so, it is necessary to provide an adjustment mechanism or the like that enables adjustment of the operation of each part in the linkage structure, resulting in a complicated structure and a decrease in assembly performance due to the adjustment work. become.

  Therefore, the controller 39 stores the correlation between the output of the upper limit setter 44 and the output of the lever sensor 49 that detects the operation limit position of the height setting lever 15 due to the mechanical linkage with the stopper 34. The control device 39 determines an output target value of the lever sensor 49 corresponding to the output of the upper limit setting unit 44 based on the correlation and the output of the upper limit setting unit 44, and the output target value of the lever sensor 49 is determined. The automatic lowering control is performed when the output values coincide with each other. According to this configuration, the operation of the stopper 34 is changed to the operation of the upper limit setting device 44 linked to the stopper 34. The operation of the height setting lever 15 is not only applied to the detection operation of the lever sensor 49 linked to the operation of the height setting lever 15. Even when the operation of the linkage mechanism that converts to the detection operation of 9 is affected, the output value of the upper limit setter 44 (the output target value of the lever sensor 49) of the lever sensor 49 is taken into consideration in the influence of those effects. It is possible to accurately determine whether or not the output values match (whether the height setting lever 15 contacts the stopper 34). As a result, the height setting lever 15 contacts the stopper 34. However, the control device 39 does not determine that the height setting lever 15 has come into contact with the stopper 34 and the automatic lowering control is not performed, so that the position control cannot be performed. Since the control device 39 determines that the height setting lever 15 is in contact with the stopper 34 from the stage before the contact with the stopper 34, the position control becomes possible. That The height setting lever 15 can be avoided inconveniences that the working device in conjunction with operations up to brought into contact with the stopper 34 rises unexpectedly, the occurrence of the advance of the.

  As a result, after performing automatic ascent control to automatically raise the rotary tiller 7 to the upper limit position, the height position (working height position) of the rotary tiller 7 corresponding to the current operating position of the height setting lever 15 When it is desired to position the rotary tiller 7 at a different height position (for example, a height position where maintenance can be easily performed), an operation for performing automatic lowering control is performed first, and the rotary tiller 7 is The height setting lever 15 is automatically lowered to the height position corresponding to the operation position of the height setting lever 15 and the position control can be performed. Then, the height setting lever 15 is operated and the height position corresponding to the operation position is set. The position control can be performed only by operating the height setting lever 15 without performing the operation procedure of performing the position control for raising and lowering the rotary tiller 7 to the The Tali plow 7 can be located at any height position.

  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.

  In addition, the correlation between the output of the upper limit setting device 44 and the output of the lever sensor 49 is, for example, that the height setting lever 15 and the stopper 34 operated in the operation region thereof are changed in the operation region of the height setting lever 15. It is conceivable that a sampled value is acquired and established from the outputs of the upper limit setter 44 and the lever sensor 49 obtained when moving in the same direction at the same speed.

  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 upper limit setter 44 and the output of the lever sensor 49 can be established simultaneously.

  Specifically, in a state where the control mode of the control device 39 is switched from the normal mode to the adjustment mode, the height setting lever 15 is contacted with the stopper 34 in a state in which the position changing operation is enabled by loosening the knob bolt 34A. 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 (end position in the ascending direction) while maintaining the contact state. The control device 39 samples 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 with the operation, every predetermined time. 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 setter 44, and the output of the upper limit setter 44 and the lever sensor 49. It is configured to establish the correlation between the output.

  As a result, the upper limit position of the rotary tiller 7 by the position control by the height setting lever 15 and the automatic operation by the lifting motor 35 can be performed without providing an adjustment mechanism or the like in each linkage structure. It is possible to avoid the inconvenience that the height position of the rotary tiller 7 is greatly different from the upper limit position of the rotary tiller 7 in the ascending control, and the cabin 14 of the rotary tiller 7 that may be caused by the inconvenience. And the setting position of the stopper 34 based on the output of the upper limit setting device 44 does not match the operation upper limit position of the height setting lever 15 based on the output of the lever sensor 49. The operation upper limit position of the height setting lever 15 after the automatic raising to the upper limit position of the rotary tiller 7 by automatic raising control due to When the position control is enabled by this operation, the rotary tiller 7 is raised, or the position control cannot be enabled even if the height setting lever 15 is operated to the operation upper limit position. Can be avoided.

  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 upper limit setter 44 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 upper limit setter 44 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 If the output line of 44 or the output line of the upper limit setter 44 is completely different from the output line of the lever sensor 49, a plurality of sampling data obtained by fine sampling is controlled. By storing in the nonvolatile memory of the device 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 to make it.

  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.

  Further, when the simultaneous operation of the backup switch 51 and the drive changeover switch 52 is performed in the normal mode or the adjustment mode, for example, when the simultaneous operation of the backup switch 51 and the drive changeover switch 52 is performed, the elevating motor 35 is rotated forward only while the operation is continued. When the left and right lift arms 18 are swung up and swinged, and the simultaneous operation of the drive changeover switch 52 and the rolling switch 53 is performed, for example, which is not normally performed, the lift motor 35 is reversed only while the operation is continued. It is configured such that the control operation of the control device 39 for the lifting motor 35 is switched to the state where the left and right lift arms 18 are swung downward, and the lifting motor 35 is operated by operating the ascending switch 40 or the descending switch 41. This makes it easier to investigate the cause of the failure, and the lowering switch 41 and the upper limit setting device 44 or lever set. 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 the support 49 that can not be performed at all may be avoided.

[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] As shown in FIG. 10, a switch 55 for detecting the contact of the height setting lever 15 with respect to the contact type restricting means 34 is provided on the receiving tool 34 </ b> C of the contact type restricting means 34. When the switch 55 detects this, the control device 39 may be configured to control the operation of the electric actuator 35 to perform automatic lowering control. As the switch 55, a limit switch, a pressure switch, a proximity switch, or the like can be employed.

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

[9] The one-sided linkage portion 22 may be arranged on the lower side in the operation direction than the swing link 28 serving as a linkage portion between the operation linkage mechanism 23 and the feedback linkage mechanism 24.

[10] The height position detecting means 38 detects, for example, the swing position of the operating 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 The side view of the principal part which shows the structure of the raising / lowering operation structure in another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 6 Hydraulic type operating mechanism 7 Working device 15 Height setting lever 19 Control valve 22 Contact type linkage part 23 Operation linkage mechanism 24 Feedback linkage mechanism 28 Linkage part 34 Contacting type | formula limitation means 35 Electric actuator 38 Height position detection means 39 Control Device 44 Upper Limit Setter 46 Elevation Command Means 49 Lever Sensor 55 Switch

Claims (4)

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,
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 unit that enables setting change of the upper limit position in the automatic ascent control, and a height position detection unit that detects a height position of the working device,
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 determines an output target value of the height position detection means corresponding to the output of the upper limit position setting means based on the output of the upper limit position setting means and the correlation, and the automatic increase In the control, the operation structure for raising and lowering the work vehicle configured to control the operation of the electric actuator until the output value of the height position detecting means matches the determined output target value.   The one-side contact type linking portion is arranged on the upper side in the operation direction than the linkage portion between the operation linking mechanism and the feedback linking mechanism, and the height position detecting means is an operation position of the one-side contact type linking portion. The operation structure for raising and lowering a work vehicle according to claim 1, wherein the structure is configured to detect the vehicle. A lever position detecting means for detecting the operation position of the height setting lever is provided, and the control means stores a correlation between the output of the upper limit position setting means and the output of the lever position detecting means,
The lever corresponding 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 lever position detection means. 3. The automatic lowering control is configured to determine the output target value of the position detecting means and perform the automatic lowering control when the output value of the lever position detecting means coincides with the output target value. Lifting and lowering structure of the work vehicle.   The contact-type restricting means is provided with a switch for detecting contact of the height setting lever with the contact-type restricting means, and the control means is based on an output when the switch detects the contact. The lifting / lowering operation structure for a work vehicle according to claim 1 or 2, wherein the automatic lowering control is configured to perform the automatic lowering control.

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