Riding type mower

Abstract

To provide a riding type mower that prevents disorder of a mowing device in movement travel not accompanied by mowing work, and can improve safety.SOLUTION: A riding type mower includes: a traveling machine body 2; a mowing device 6; a lifting hydraulic cylinder 78; a travel detection member for detecting the travel and speed of the traveling machine body 2; height position detection means for detecting a height position of the mowing device 6; a drive operation switch 8a for operating the drive of the mowing device 6; and a control section 90 for controlling the telescopic motion of the lifting hydraulic cylinder 78. The control section 90 is constituted so as to acquire detection information of the travel detection member and detection information of the height position detection means, automatically lift up the mowing device 6 when the height position of the mowing device 6 is lower than a predetermined set position in a state that the drive of the mowing device 6 is stopped and the traveling machine body 2 travels for a predetermined time, and descend the mowing device 6 when the drive operation switch 8a is operated when the height position of the mowing device 6 is higher than the predetermined set position.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a riding lawn mower that performs mowing work.

Background Art

[0002] Conventionally, as this type of riding lawn mower, for example, those described in Patent Document 1 and Patent Document 2 are known. This conventional riding lawn mower is provided with a mowing device at the front of the (traveling) machine body (so-called front mower). Further, the mowing device is configured to be able to move up and down by the expansion and contraction of a hydraulic cylinder, and thereby, it is possible to switch between a working position for performing mowing work and a non-working position retracted upward from the working position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of the conventional riding lawn mower, when moving without performing mowing work, it is desirable to retract the mowing device to the non-working position. However, there is a risk that the operator may forget the operation after the work and drive while the mowing device is in the working position. As a result, the mowing device becomes a factor that causes a failure (such as damage to the blade or damage to the mower deck) when it comes into contact with an obstacle or a step. Further, when the mowing device is accidentally driven while in the non-working position during moving travel, there is a possibility that the blade may come into contact with the outside, so there is room for improvement in terms of safety.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a riding lawn mower that can prevent a failure of the mowing device and improve safety during moving travel without performing mowing work.

Means for Solving the Problem

[0006] To achieve the above object, a first invention provides a traveling machine body configured to be able to travel with traveling wheels, a grass cutting device located at the front of the traveling machine body, a hydraulic cylinder for lifting and lowering the grass cutting device by expansion and contraction, a traveling detection member for detecting the traveling and speed of the traveling machine body, a height position detection means for detecting the height position of the grass cutting device, a drive operation switch for operating the drive of the grass cutting device, and a control unit for controlling the expansion and contraction of the hydraulic cylinder for lifting and lowering, wherein the control unit acquires the detection information of the traveling detection member and the detection information of the height position detection means, and when the height position of the grass cutting device is below a predetermined set position and the traveling machine body travels for a predetermined time in a state where the drive of the grass cutting device is stopped, the control unit controls the hydraulic cylinder for lifting and lowering to automatically raise the grass cutting device. Also, when the height position of the grass cutting device is above the predetermined set position and the drive operation switch is operated, the control unit controls the hydraulic cylinder for lifting and lowering to lower the grass cutting device. A riding-type lawn mower is provided with such a configuration.

[0007] According to the first invention, when the driving of the mowing device stops, the height position of the mowing device is below a predetermined set position, and when the traveling machine body travels for a predetermined time, the lifting hydraulic cylinder is controlled to automatically raise the mowing device. Thus, during moving travel, it is possible to prevent the mowing device from contacting obstacles or steps and malfunctioning. In addition, since the operator is saved the trouble of manually raising the mowing device each time work is completed, convenience can be greatly improved. Further, when the height position of the mowing device is above the predetermined set position, when the drive operation switch is operated, the lifting hydraulic cylinder is controlled to lower the mowing device (without driving the mowing device). Thus, during moving travel, it is possible to prevent the mowing device from being accidentally driven when it is in the non-working position (raised state), and thereby prevent the situation where the blade of the cutter contacts the outside. As a result, safety can be improved.

[0008] The second invention, in addition to the configuration of the first invention, is provided with a lifting operation lever for operating the lifting of the mowing device, and the control unit is characterized in that when the lifting operation lever is operated to the upper operation position, the lowering of the mowing device by the operation of the drive operation switch is restricted.

[0009] According to the second invention, in addition to the effects of the first invention, it is possible to prevent the situation where the mowing device descends contrary to the operation position of the lifting operation lever, and by performing a lifting operation that reflects the operator's operation intention (by the lifting operation lever), it is possible to prevent unintended operations by the operator and improve safety.

[0010] The third invention, in addition to the configuration of the first or second invention, is characterized in that after starting the lowering of the mowing device by the operation of the drive operation switch, when the drive operation switch is operated again, the lowering of the mowing device is stopped and the drive is started.

[0011] According to the third invention, in addition to the effects of the first or second invention, While preventing the mowing device from being driven in the raised state, the operator can quickly start working with the mowing device at a desired height position by a simple operation (regardless of the operation of the lifting operation lever).

[0012] The fourth invention, in addition to the configuration of the first or the second invention, the control unit is characterized in that, after starting the lowering of the mowing device by the operation of the drive operation switch, when the mowing device reaches the work start position, the lowering of the mowing device is stopped and the drive is started.

[0013] According to the fourth invention, in addition to the effects of the first or the second invention, when the mowing device reaches the work start position due to the lowering, according to the configuration in which the driving of the mowing device is automatically started, the labor of the operator for performing the work start operation is saved and the work can be started quickly, so the convenience is good.

Effects of the Invention

[0014] According to the present invention, it is possible to provide a riding mower that can prevent failures of the mowing device and improve safety during moving travel without mowing work.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0016] <Overall Configuration of Riding Mower 1> Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the forward direction of the riding mower 1 is defined as "front", the opposite direction as "rear", the right direction when facing forward as "right", and the left direction as "left". Each direction is defined for convenience of explanation, and the present invention is not limited by these direction definitions themselves.

[0017] A left side view of the main part of the riding mower according to the present embodiment is shown in FIG. 1, and a front cross-sectional view of the riding mower according to the present embodiment is shown in FIG. 2. The riding mower 1 has a traveling body 2 (hereinafter sometimes simply referred to as the body 2) equipped with a pair of left and right front wheels 3L (3R) and rear wheels 4L (4R), and a mowing device 6 (mower 6) having a cutter 5 that rotates around a vertical axis is provided below the front part of the body 2.

[0018] A steering column 8 is erected on the floor 7 above the front part of the body 2, and a handle 10 is provided at the upper part of the column 8. Also, a driver's seat 11 is provided behind the handle 10, and an engine 12, a radiator 13, and a bonnet 14 covering them are arranged behind the driver's seat 11. A collector 16 is provided above the bonnet 14, and a fender 22 is provided on the side of the driver's seat 11. Also, an accelerator pedal 7a for performing an accelerator operation by a stepping operation is disposed on the floor 7. Further, an operation switch 8a, which is a pressing type switch for performing an operation related to the drive of the mowing device 6 described later, is provided on the steering column 8.

[0019] The engine 12 transmits power to a distribution transmission shaft 51 that transmits power from an output shaft 12a arranged at the front thereof into a transmission case 24 (see FIG. 4). Further, a hydrostatic continuously variable transmission (hereinafter referred to as HST) 40 is mounted on the rear surface side of the transmission case 24, and a blower case 18 is detachably provided on the front surface side of the transmission case 24 via a spacer (not shown) also serving as a shaft support metal.

[0020] The drive operation switch 8a is a switch for an operator to operate the drive of the mowing device 6 (for example, start and stop of the rotational drive of the cutter 5) by pressing the switch. Note that the operation switch 8b may be a switch with a lighting lamp, and may indicate the drive and lifting states of the mowing device 6 according to the lighting pattern. For example, it may be in a lit state when the cutter 5 is rotationally driven and in an extinguished state when it is stopped.

[0021] In addition, an operation lever 19 that an operator operates according to the work is provided on the side of the operator's seat 11. This operation lever 19 is composed of a plurality of lever members with different roles. More specifically, it includes a lifting operation lever 19a for operating the lifting of the mowing device 6 described later, a throttle lever 19b for adjusting the output of the engine 12, and a parking lever 19c for restricting the rotation of the rear wheels 4L (4R) when the vehicle body 2 stops. Note that the operation of the operation lever 19 is detected by an operation lever sensor S6, and the detected operation information is configured to be acquired by a control unit 90 described later.

[0022] FIG. 3 is a schematic side view around the lifting operation lever 19a of FIG. 1. As shown in FIG. 3, the lifting operation lever 19a includes a gripping portion 191, a rod portion 192, a rotating plate 193, and a pivot shaft portion 194 formed of a synthetic resin member. When an operator operates the gripping portion 191 either forward or backward, the rod portion 192 integrated with the gripping portion 19 rotates about the pivot shaft portion 194, and accordingly, the rotating plate 193 rotates. Further, the operation position of the lifting operation lever 19a can be detected by a potentiometer 195. More specifically, a pin body 193a provided on the rotating plate 193 is engaged with an engaging portion 195b that branches into two branches from the detection shaft 195a of the potentiometer 195 toward the tip side. Thus, as the rotating plate 193 rotates, the engaging portion 195b and the detection shaft 195a rotate, and the rotation angle of the detection shaft 195a is detected by the potentiometer 195, thereby detecting the operation position of the lifting operation lever 19a. Note that this potentiometer 195 is included in the above-described operation lever sensor S6. The lifting operation lever 19a is configured to be switchable among three positions, for example, an upper operation position for raising the mowing device 6, a lower operation position for lowering it, and a neutral position (neutral position) where no lifting is performed.

[0023] The mowing device 6 receives the transmission of the power of the engine 12 via a PTO shaft for mowing device (mower PTO shaft) 28 (see FIG. 4), and thereby rotates the cutter 5 to perform the function of mowing the grass on the work area (such as a field). Since the mowing device 6 itself can adopt a known configuration, a detailed description thereof is omitted. For example, refer to Japanese Unexamined Patent Application Publication No. 2023-157741.

[0024] In addition, the mowing device 6 is rotatably attached to the machine body 2 by a pair of left and right lift links 71, and by the telescopic operation of a hydraulic cylinder 78 for mower lifting disposed on one side (for example, the right side) of the left and right sides of the machine body 2, the lift link 71 is rotated about the rotation fulcrum 71a, so that the mowing device 6 can be lifted and lowered as will be described later. Although not shown, the rotation center axis 71a of the lift link 71 is supported by a vertical arm fixed to the machine body 2. In this way, the height position of the mowing device 6 with respect to the machine body 2 (and the running surface) is a mechanism determined by the stroke amount (telescopic amount) of the hydraulic cylinder 78 for lifting. The mowing device 6 can be lifted and lowered within a lifting range W from the lower limit position Pmin shown in FIG. 1 to the upper limit position Pmax shown in FIG. 2.

[0025] In addition, an upper limit limit switch S3 that abuts against the lift link 71 at the upper limit position Pmax and detects that the mowing device 6 has reached the upper limit position Pmax of the lifting range, and a lower limit limit switch S4 that abuts against the lift link 71 at the lower limit position Pmin and detects that the mowing device 6 has reached the lower limit position Pmin are provided at appropriate positions of the machine body 2. Further, a wire type displacement sensor S5 is provided at an appropriate position of the machine body 2, and by detecting the pulling amount of the wire interlocked with the height of the mowing device 6, the height position (vertical position) of the mowing device 6 can be detected well. The upper limit limit switch S3, the lower limit limit switch S4, and the wire type displacement sensor S5 function as height position detection means that are means for detecting the height position of the mowing device 6.

[0026] In addition, a blower case 18 with a blower 17 having an axis in the front-rear direction is installed below the driver's seat 11 and between the left and right front wheel drive cases 23L and 23R, and the blower 17 is operated by the output of the engine 12. A duct 20 for transporting mowed grass that connects the blower case 18 and the collector 16 is provided at the upper part of the blower case 18. Further, a shooter 21 having a rear-rising shape in side view is arranged between the blower 17 and the mowing device 6. The mowed grass cut by the mower 6 is sent from the discharge port at the center of the rear part of the mower deck 6a to the blower 17 via a short cylindrical guide part 6b and the shooter 21 whose end can be bent by overlapping it with this guide part 6b, and is further air (wind force) transported to the rear collector 16 via the duct 20.

[0027] <2. Transmission Configuration of the Riding Mower 1> Next, with reference to FIG. 4, the transmission configuration of the riding mower 1 will be briefly described. FIG. 3 is a transmission diagram of the riding mower 1 according to the present embodiment. As shown in FIG. 4, in the riding mower 1, the power (rotational power) output from the engine 12 is transmitted to a distribution transmission shaft 51 connected to the output shaft 12a of the engine 12, and is transmitted to a blower PTO shaft 52A. The rotational power output from the blower PTO shaft 52A is transmitted to the above-described blower 17 via, for example, a blower transmission device (such as a gear transmission device).

[0028] Also, the rotational power output from the distribution transmission shaft 51 is transmitted to the drive wheels via a traveling transmission device, and the trunnion shaft is tilted and the hydraulic motor 40b is shifted via the hydraulic pump 40a of the HST40. The riding mower 1 is configured to be able to switch between two-wheel drive (2WD) and four-wheel drive (4WD). For this reason, the drive wheels are, when the riding mower 1 is in 2WD, either the left and right front wheels 3L, 3R or the left and right rear wheels 4L, 4R (for example, the left and right front wheels 3L, 3R), and when the riding mower 1 is in 4WD, the left and right front wheels 3L, 3R and the left and right rear wheels 4L, 4R.

[0029] In the case of 4WD, the rotational power output from the transfer drive shaft 51 is transmitted to the front wheels 3L (3R) via the hydraulic pump 40a and the hydraulic motor 40b of the HST40, and via the gear transmission device 54a and the differential mechanism 54b in the differential case 54. Also, the rotational power output from the transfer drive shaft 51 is transmitted to the rear wheels 4L (4R) via the hydraulic pump 40a and the hydraulic motor 40b of the HST40, and via the gear transmission device 55a and the differential mechanism 55b in the differential case 55.

[0030] Further, the rotational power output from the transfer drive shaft 51 is transmitted to the PTO shaft 28 for the mowing device. The rotational power output from the PTO shaft 28 for the mowing device is transmitted to the cutter 5 described above via the mower input shaft (not shown) and the mower transmission device 6d of the mower deck 6a (see FIGS. 1 and 3).

[0031] Note that a blower clutch 56A for turning on and off the power transmission from the transfer drive shaft 51 to the blower PTO shaft 52A and a mowing device clutch (mower clutch) 56B for turning on and off the power transmission from the transfer drive shaft 51 to the PTO shaft 28 for the mowing device are provided, and the blower clutch 56A and the mowing device clutch 56B are configured to be controlled to be turned on and off (on / off) by a control unit C described later.

[0032] <3. Control System of Riding Mower 1> Here, with reference to FIG. 5, the control system of the riding mower 1 centered on the control unit 90 will be described. FIG. 5 is a block diagram centered on the control unit 90 of the riding mower 1.

[0033] The control unit 90 can control each part of the riding lawn mower 1 by electronic control, and includes a processing unit having a CPU (Central Processing Unit) and the like. More specifically, it includes an engine ECU (Electronic Control Unit) 91, a traveling system ECU 92, and a working implement system ECU 93. Further, the control unit 90 includes a storage unit 94 in which programs and data for controlling each part are stored. This storage unit 94 is composed of a hard disk, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

[0034] The engine ECU 92 controls the output of the engine 12 and the like, and the traveling system ECU 93 controls the HST 40 and the like to control the overall traveling of the machine body. The working implement system ECU 93 controls the overall driving of the mower 6, controls a solenoid valve that turns on and off the blower clutch 56A and the mowing device clutch 56B (see FIG. 4), and controls the lift hydraulic cylinder 78 to perform lift control of the mowing device 6.

[0035] Also, on the input side of the control unit 90, various sensors such as a vehicle speed sensor S1, a PTO sensor S2, an upper limit limit switch S3, a lower limit limit switch S4, a wire type displacement sensor S5, and an operation lever sensor S6 (potentiometer 195), as well as a drive operation switch 8b are connected, and it is possible to acquire detection and detection information thereof.

[0036] The vehicle speed sensor S1 is for calculating the traveling speed (vehicle speed) of the machine body 2, and derives an actual measured value of the vehicle speed from the rotation speeds of the front wheels 3L, 3R and the rear wheels 4L, 4R. Thereby, the vehicle speed sensor S1 functions as a traveling detection member for detecting the traveling of the riding lawn mower 1 (machine body 2), and the control unit 90 can calculate the traveling distance based on the detection result of the vehicle speed sensor S1. Also, the PTO sensor S2 detects the rotation speeds of the blower PTO shaft 52A and the mowing device PTO shaft 28 (see FIG. 4).

[0037] The control unit 90 configured as described above acquires various data in each part, and based on the data and the results calculated from the data, controls the operations of each part of the aircraft 2 and the grass cutting device 6. The control example of the control unit 90 will be described below.

[0038] <4. Control Example 1 of Control Unit 90 (Grass Cutting Device Driving Start Process)> FIG. 6 is a flowchart showing the flow of the grass cutting device driving start process by the control unit 90. Here, the grass cutting device driving start process is a process related to the start of driving the grass cutting device 6. From the state where the engine 12 is driving and the grass cutting device 6 is stopped (the state where the clutch 56B for the grass cutting device is "off"), the grass cutting device 6 is driven (the clutch 56B for the grass cutting device is set to "on").

[0039] When the engine 12 is driving and the grass cutting device 6 is in the stopped state, the control unit 90 starts executing the grass cutting device driving start process. As shown in FIG. 6, in the grass cutting device driving start process, first, it is determined whether the drive operation switch 8a has been pressed by the operator (step #1).

[0040] When the drive operation switch 8a is pressed (Y in step #1), it is determined whether the grass cutting device 6 is in the working position (step #2). The working position refers to the (predetermined) height position at which the grass cutting device 6 performs work (see FIG. 8). When the grass cutting device 6 is in the working position (Y in step #2), the control unit 90 starts driving the grass cutting device 6 (switches the clutch 56B for the grass cutting device to "on") (step #3). As a result, the cutter 5 rotates and the grass cutting work is performed.

[0041] When the mowing device 6 is not in the lower limit position (N in step #2), the control unit 90 determines from the detection information of the potentiometer 195 whether the lifting operation lever 19a has been operated to the lower operation position (step #4). When it has been operated to the lower operation position (Y in step #4), the lowering of the mowing device 6 is started by controlling the lifting hydraulic cylinder 78, and the mowing device 6 is lowered at a predetermined speed (step #5). On the other hand, when the lifting operation lever 19a has not been operated to the lower operation position (it is in the upper operation position) (N in step #4), the process returns to step #1. That is, the pressing operation of the drive operation switch 8a by the operator is canceled, and the mowing device 6 is not lowered. By configuring it in this way, it is possible to prevent a situation where the mowing device 6 descends contrary to the operation position of the lifting operation lever 19a, and by performing a lifting operation that reflects the operation intention of the operator (by the lifting operation lever 19a), it is possible to prevent an unintended operation of the operator and improve safety.

[0042] While the mowing device 6 is descending (after the execution of step #5), when the drive operation switch 8a is pressed again (Y in step #6), the control unit 90 determines whether the mowing device 6 is in the workable position (step #7). Here, the workable position refers to the height position within the lifting range W where the mowing device 6 can perform work. When the mowing device 6 is in the workable position (Y in step #7), the lowering of the mowing device 6 is stopped (step #8), and the drive of the mowing device 6 is started (step #3). On the other hand, when the mowing device 6 is not in the workable position (N in step #7), that is, when it is in the non-working position where work is not performed, the pressing operation of the drive operation switch 8a by the operator is canceled, and the process returns to step #6.

[0043] Also, while the mowing device 6 is descending (after the execution of step #5), the control unit 90 monitors whether the mowing device 6 has reached the work start position Ps (step #9). Here, the work start position Ps refers to the (predetermined) height position at which the mowing device 6 starts working. When the mowing device 6 reaches the work start position Ps due to descending, the control unit 90 starts driving the mowing device 6. That is, the control unit 90 stops the descent of the mowing device 6 (step #8) and starts driving the mowing device 6 (step #3) when the drive operation switch 8b is pressed at the workable position of the mowing device 6 after the start of the descent of the mowing device 6 (after the execution of step #5), or when the mowing device 6 reaches the work start position Ps. Thus, according to the configuration in which the descent of the mowing device 6 is stopped and the drive is started when the drive operation switch 8b is pressed (at the workable position), while preventing the mowing device 6 from driving in the raised state, the operator can quickly start working with the mowing device 6 at a desired height position by a simple operation (regardless of the operation of the lifting operation lever 19a). Also, according to the configuration in which the drive of the mowing device 6 is automatically started when the mowing device 6 reaches the work start position Ps due to descending, the labor of the operator for performing the work start operation is saved and the work can be started quickly, so the convenience is good.

[0044] <5. Control Example 2 of Control Unit 90 (Automatic Ascent Process of Mowing Device)> FIG. 7 is a flowchart showing the flow of the automatic ascent process of the mowing device by the control unit 90. The automatic ascent process of the mowing device starts execution when the mowing device 6 is in the driving state (the state where the mowing device clutch 56B is "engaged"), and automatically raises the mowing device 6 (height position) when a predetermined condition is satisfied.

[0045] When the mowing device 6 is in a driving state (when the mowing device 6 starts driving), the control unit 90 starts the automatic raising process of the mowing device. As shown in FIG. 7, when the automatic raising process of the mowing device is started, the control unit 90 monitors whether the mowing device 6 has stopped driving (step #11). When it is determined that the mowing device 6 has stopped driving (Y in step #11), it is determined whether the height position of the mowing device 6 is below the set position (it may be below or equal to the set position.) (step #12). Here, the set position is the height position of the mowing device 6 that can be set in advance by the operator through a predetermined operation, and is set, for example, to be the lower limit height position of the non-working position. That is, it is desirable that the height of the set position is set such that above the set position, the mowing device 6 retreats upward without performing work, and below the set position, it is a height position where work can be performed. Note that the information related to this set position is stored in the storage unit 94.

[0046] When it is determined that the height position of the mowing device 6 is below the set position (Y in step #12), the count of the stop time of the mower 6 is started (step #13), and the count of the travel distance of the riding mower 1 is started (step #14). Here, the travel distance may be calculated by multiplying the detected value of the vehicle speed sensor S1 by time, or the vehicle speed may be calculated considering the gear ratio and tire diameter.

[0047] Subsequently, it is determined whether the mowing device 6 has been driven (step #15). When the mowing device 6 has not been driven (N in step #15), it is determined whether the mowing device 6 has moved to a height above the set position (step #16). When the mowing device 6 has not moved to a height above the set position (N in step #16), it is determined whether the count of the stop time is equal to or greater than the set time (step #17), and whether the count of the travel distance is equal to or greater than the set distance (step #18). Here, the set values of the set time and the set distance can be set in advance by the operator, and it is desirable that the set time is, for example, 30 seconds and the set distance is, for example, about 3 m (meters). Note that the information related to the set time and the set distance is stored in the storage unit 94.

[0048] Here, when the mowing device 6 is driven (Y in step #15) or when the mowing device 6 is moved to a height equal to or higher than the set position (Y in step #16), the counting of the stop time and the travel distance is reset, and the process returns to step #11.

[0049] When the count of the stop time has not reached the set time (N in step #16) and the count of the travel distance has not reached the set distance (N in step #17), while continuing the count, the process returns to step #15.

[0050] On the other hand, when the count of the stop time becomes equal to or more than the set time (Y in step #16) or when the count of the travel distance becomes equal to or more than the set distance (Y in step #17), the control unit 90 raises the height position of the mowing device 6 by controlling the lifting hydraulic cylinder 78 (step #19). Here, it is desirable that the height position of the mowing device 6 to be raised is configured to be raised to the non-operating position, but it may also be configured such that the operator can set a desired height position in advance. Also, it may be configured to be raised up to the upper limit position Pmax. When the height position of the mowing device 6 is raised, the counting of the stop time and the travel distance is reset (step #20), and the process ends.

[0051] According to the above configuration, when the grass cutting device 6 stops driving and a predetermined set time elapses, or when the riding lawn mower 1 travels a distance equal to or greater than a predetermined set distance, the control unit 90 automatically raises the grass cutting device 6. Thereby, it is possible to satisfactorily prevent a situation where the grass cutting device 6 remains lowered during non-operation and the vehicle travels due to the operator's forgetfulness or the like. As a result, it is possible to prevent the grass cutting device 6 from coming into contact with obstacles or steps, and the safety during moving travel without grass cutting work can also be improved. In addition, since the operator is saved the trouble of manually raising the grass cutting device 6 each time work is completed, convenience can be greatly improved. Note that when the predetermined time elapses, the lifting hydraulic cylinder 78 is controlled to automatically raise the grass cutting device 6, so that the grass cutting device 6 can be automatically raised when the operator leaves the seat, thereby improving safety. Note that when the grass cutting device 6 is automatically raised by this grass cutting device automatic raising process, a situation may occur where the grass cutting device 6 is rising while the lift operation lever 19a is operated to the lower operation position. At this time, an alarm is displayed on a predetermined display unit (for example, a monitor provided in front of the driver's seat 11), and when the operator once operates the lift operation lever 19a to the upper operation position, the grass cutting device 6 is moved to the upper limit position Pmax, and the deviation between the operation position of the lift operation lever 19a and the height position of the grass cutting device 6 due to the automatic raising of the grass cutting device 6 may be eliminated.

[0052] FIG. 8 is an explanatory diagram for explaining the positional relationship related to the height position of the grass cutting device 6. In the execution of the above processing, as shown in FIG. 8, among the raising and lowering range W of the mowing device 6, the upper limit is the upper limit position Pmax and the lower limit is the lower limit position Pmin. The positional relationship related to the height position of the mowing device 6 shown in FIG. 8 can be set in the storage unit 94. First, the height position of the mowing device 6 in the raising and lowering range W can be divided into a non-operating position where the mowing device 6 does not perform work and an operable position where work can be performed. The height position that is the boundary between this non-operating position and the operable position is the work stop position Pt because it is the boundary position where the work stops in the state where the mowing device 6 is driven. The work stop position Pt is a set position where the operator can set the height in advance, and it is the reference height position used in the determination in the above-described automatic raising process of the mowing device. Also, among the operable positions, the height at which work is actually performed is set as the work position. This work position may be set within a range of a predetermined height from the lower limit position Pmin, or the height of the lower limit position Pmin may be set as the work position. Also, within the range of the work position, a work start position Ps is set. Note that the work start position Ps may be set at the same height as the lower limit position Pmin.

[0053] With the setting of the positional relationship related to the height position of the mowing device 6 as described above, when the operator manually operates the raising and lowering of the mowing device 6 using the raising and lowering operation lever 19a, the control unit 90 preferably controls to temporarily stop when the raising and lowering operation lever 19a is operated to the lower operation position and the mowing device 6 reaches the work start position Ps due to the lowering when the mowing device 6 is lowered. Also, when the raising and lowering operation lever 19a is operated to the upper operation position and the mowing device 6 is raised, it is preferably controlled to automatically stop the drive of the mowing device 6 when the work stop position Pt is reached due to the raising.

[0054] The embodiments of the present invention have been described above. It goes without saying that the present invention is not limited only to the aspects of the above-described embodiments and can be appropriately changed within the scope of the technical idea.

Explanation of Reference Numerals

[0055] 1 Riding mower 2 Traveling body 3 Front wheels 4 Rear wheels 5 Cutter 6 Grass cutting device (mower) 6a Mower deck 6b Guide part 7 Floor 8 Steering column 8a Drive operation switch 10 Handle 11 Operator's seat 12 Engine 12a Engine output shaft 13 Radiator 14 Bonnet 16 Collector 17 Blower 18 Blower case 20 Duct 21 Shooter 22 Fender 23 Front wheel drive case 24 Transmission case 40 Hydrostatic continuously variable transmission (HST) 90 Control unit

Claims

1. A traveling machine body configured to be able to travel with traveling wheels, A mowing device located at the front of the traveling machine body, A lifting hydraulic cylinder that raises and lowers the mowing device by expansion and contraction, A traveling detection member that detects the traveling and speed of the traveling machine body, Height position detection means for detecting the height position of the mowing device, A drive operation switch for operating the drive of the mowing device, And a control unit that controls the expansion and contraction of the lifting hydraulic cylinder, The control unit acquires the detection information of the traveling detection member and the detection information of the height position detection means, and when the height position of the mowing device is below a predetermined set position and the traveling machine body travels for a predetermined time in a state where the drive of the mowing device is stopped, the control unit controls the lifting hydraulic cylinder to automatically raise the mowing device. Also, when the height position of the mowing device is above a predetermined set position, when the drive operation switch is operated, the control unit controls the lifting hydraulic cylinder to lower the mowing device. A riding mower characterized by this.

2. It is provided with a lifting operation lever for operating the lifting of the mowing device, The control unit restricts the lowering of the mowing device by the operation of the drive operation switch when the lifting operation lever is operated to the upper operation position. The riding mower according to Claim 1.

3. The control unit stops the lowering of the mowing device and starts the drive when the drive operation switch is operated again after starting the lowering of the mowing device by the operation of the drive operation switch. The riding mower according to Claim 1 or Claim 2.

4. After the control unit starts the lowering of the mowing device by the operation of the drive operation switch, When the mowing device reaches the work start position, the control unit stops the lowering of the mowing device and starts the drive. The riding mower according to Claim 1 or Claim 2.

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