JP2015181473A - Lawn-mowing vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lawn-mowing vehicle capable of uniformizing furthermore the lawn-mowing state of each lawn-mowing mechanism during turning of the lawn-mowing vehicle.SOLUTION: A lawn-mowing vehicle including a plurality of lawn-mowing mechanisms 5A, 5B, 6 having rotary cutters 15 rotated by a motor 17 also includes a steering angle sensor 31 for detecting a steering angle θ of a rear wheel 4 of the lawn-mowing vehicle, and a control device 33 for controlling rotational speed of the rotary cutters 15 relative to each of the plurality of lawn-mowing mechanisms 5A, 5B, 6 on the basis of the steering angle θ detected by the steering angle sensor 31.

Description

  The present invention relates to a lawnmower vehicle.

  2. Description of the Related Art Lawn mowing vehicles that can mow a large area of lawn by providing a plurality of lawn mowing mechanisms that rotate a rotary blade to mow the lawn are conventionally known. Although not limited to lawnmower vehicles, when the vehicle is in a turning state, positions having different turning radii have different turning speeds in the vehicle portion. Therefore, in a lawnmower vehicle in a turning state, the turning speed (speed) of the lawnmower mechanism arranged outside the turn is higher than the turning speed (speed) of the lawnmower mechanism arranged inside the turn. And become faster. Thus, when the lawn mowing vehicle is in a turning state, if the turning speed is different between lawn mowing mechanisms arranged at different turning radii, the lawn mowing mechanism with a faster turning speed results in insufficient lawn mowing. There is a problem that the lawn mowing state is different between the lawn mowing mechanisms.

  Focusing on this problem, Patent Document 1 discloses that the rotational speeds (the number of rotations per unit time) of the rotary blades of the plurality of lawn mowing mechanisms are changed according to the steering angle (rotation angle) of the lawnmower vehicle. Thus, it is disclosed that the lawn mowing state between the lawn mowing mechanisms is made uniform.

Japanese Utility Model Publication No. 61-188421

  However, the correspondence between the turning angle of the steering wheel and the turning radius of the lawn mower vehicle is difficult to accurately match, and the lawn mowing state between the lawn mowing mechanisms during turning of the lawn mower vehicle cannot be sufficiently aligned. is there.

  Then, this invention makes it a subject to provide the lawn mowing vehicle which can make the lawn mowing state of the lawn mowing mechanisms more uniform at the time of turning of the lawn mowing vehicle.

  In order to achieve the above object, the present invention provides a rudder angle detecting means for detecting a rudder angle of a steered wheel of a lawnmower vehicle in a lawnmower vehicle having a plurality of lawnmower mechanisms having rotating blades rotated by a rotation driving means. And control means for controlling the rotational speed of the rotary blade for each of the plurality of lawn mowing mechanisms based on the rudder angle detected by the rudder angle detecting means.

  Further, in the lawnmower vehicle of the present invention, the control means is configured to calculate, based on the rudder angle, a turning radius at a predetermined position of the rotary blade provided in each of the plurality of lawn mowing mechanisms and a turning radius at a predetermined position of the lawnmower vehicle. It is preferable to calculate the ratio and control the rotation speeds of the rotary blades of the plurality of lawn mowing mechanisms based on the ratio.

  In the lawnmower vehicle of the present invention, it is preferable that the predetermined position of the lawn mower vehicle is a symmetrical center position of wheels serving as driving wheels.

  As described above, the lawn mowing vehicle of the present invention can make the lawn mowing state of the lawn mowing mechanisms more uniform when turning the lawn mowing vehicle.

It is the perspective view which looked at the lawnmower vehicle from the upper left front. It is a left view of a lawnmower vehicle. It is a block diagram which shows schematic structure of a lawnmower vehicle. It is a figure which shows the schematic structure of a steering mechanism. It is a figure explaining the relationship between the steering angle of a rear wheel, each turning radius of a front wheel on either side, the turning radius of the center of a front wheel on either side, and the turning radius of a rear wheel. It is a figure explaining the relationship between each turning position of the lawn mowing vehicle, each center position of the left and right rotary blades, and each coordinate position of the center position of the rear rotary blade. It is a graph which shows ratio of the turning radius of the center position of each rotary blade. It is a figure which shows the structure of the modification of a lawn mower vehicle.

  Hereinafter, a configuration of a lawnmower vehicle 1 will be described as an example of an embodiment of the present invention with reference to the drawings.

(Overall configuration of lawn mowing vehicle 1)
1 and 2 are drawings showing an external configuration of the lawnmower vehicle 1. FIG. 1 is a perspective view of the lawnmower vehicle 1 as viewed from the upper left front, and FIG. 2 is a left side view of the lawnmower vehicle 1. In the following description, the forward direction (arrow X1) of the lawnmower vehicle 1 is the front side (front), the opposite direction (arrow X2) is the rear side (rear), and the left hand side (arrow Y1) toward the front. ) As the left side (left side) and the right hand side (arrow Y2) as the right side (right side). The ground contact side (arrow Z1) of the lawnmower vehicle 1 will be described below, and the opposite side (arrow Z2) will be described as upward.

  The lawn mowing vehicle 1 includes a frame 2, two front wheels 3A and 3B arranged on the left and right in front, one rear wheel 4 arranged on the rear, and two front lawn mowing mechanisms arranged on the left and right in the front. 5A, 5B and a rear lawn mowing mechanism 6 disposed rearward. The rear wheel 4 is disposed at the center in the left-right direction of the lawnmower vehicle 1. The rear lawn mowing mechanism 6 is also arranged at the center in the left-right direction of the lawn mowing vehicle 1. The front wheels 3A and 3B are drive wheels. The rear wheel 4 is a driven wheel and functions as a steering wheel. The lawn mowing vehicle 1 cuts turf with the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 along the traveling path while traveling with the front wheels 3A and 3B and the rear wheel 4. The lawn mowing vehicle 1 is driven by an engine 24 (see FIG. 3), and is driven by a motor 17 to operate the front lawn mowing mechanisms 5A, 5B and the rear lawn mowing mechanism 6 to mow the lawn. It is a vehicle.

  A seat 7 on which an operator (driver) sits is disposed substantially at the upper center of the frame 2. A steering wheel 8 is provided on the front upper portion of the seat 7. A forward accelerator pedal 9, a reverse accelerator pedal 10, and a brake pedal 11 are provided at the lower front portion of the seat 7. The steering wheel 8 is operated by an operator seated on the seat 7 to determine the traveling direction of the lawn mowing vehicle 1, and the forward accelerator pedal 9, the reverse accelerator pedal 10, and the brake pedal 11 are operated, thereby mowing the lawn. Forward, reverse, stop, and travel speed (vehicle speed) of the vehicle 1 are determined.

  The front wheels 3 </ b> A and 3 </ b> B are driven by the power of a hydraulic motor 28 (see FIG. 3), which will be described later, housed in a hood 12 disposed behind the seat 7. The rear wheel 4 is configured such that the steering angle can be changed in the left-right direction in accordance with the rotation angle (cutting angle) of the steering wheel 8. That is, the traveling direction of the lawnmower vehicle 1 can be changed by the operator rotating the steering wheel 8.

  In the hood 12, in addition to the engine 24, hydraulic pumps 25A and 25B, a generator 26, a battery 27 (see FIG. 3) and the like which will be described later are housed. The box 13 provided on the left side of the lawnmower vehicle 1 houses a control device 33 that controls the operation of the lawnmower vehicle 1, motor drivers 17A, 17B, 17C, 22A1, 22B1, and 22C1 (see FIG. 3). Has been.

  The front lawn mowing mechanisms 5A and 5B are supported to be movable up and down in front of the front wheels 3A and 3B. When the front lawn mowing mechanism 5A, 5B is lowered, it comes into contact with the ground in front of the front wheels 3A, 3B, and can cut the lawn.

  As shown in FIG. 2, each of the front lawn mowing mechanisms 5A and 5B includes a front roller 14, a rotary blade (reel) 15, a rear roller 16, a motor 17 that rotates the rotary blade 15, and a saturation roller 18. A receiving blade 19 and a bucket 20. The front roller 14 is a substantially cylindrical member having a rotational axis set in the left-right direction of the vehicle and a plurality of grooves along the circumferential direction formed in the axial direction, and is disposed in front of the rotary blade 15. Unlike the front roller 14, the rear roller 16 is a substantially cylindrical member that is not formed with a groove, and the rotation axis is set in the left-right direction of the vehicle. The front roller 14 and the rear roller 16 are provided to support the front lawn mowing mechanisms 5A and 5B in a lowered state on the ground.

  The rotary blade 15 is a substantially cylindrical member in which a plurality of spiral blades for mowing the lawn are formed on the side surface, and the rotation axis is set in the left-right direction of the vehicle, and is driven by the motor 17. The rotary blade 15 and the receiving blade 19 are disposed between the front roller 14 and the rear roller 16, and are disposed above the front roller 14 and the rear roller 16 by the height of the lawn after cutting. Has been. The grass to be cut is sandwiched between the rotary blade 15 and the receiving blade 19 and cut by the rotating rotary blade 15. The height positions of the rotary blade 15 and the receiving blade 19 with respect to the ground contact surfaces of the front roller 14 and the rear roller 16 can be finely adjusted within a range of, for example, several mm to several tens of mm.

  Between the front roller 14 and the rotary blade 15, a thatching roller 18 is disposed. Thatching roller 18 is a roller for scraping off the turf that has entered the lawn immediately before the turf is cut by the rotary blade 15. The cut grass is accommodated in the bucket 20.

  A support arm 21A extending leftward from the center and a support arm 21B extending rightward from the center are provided at the front of the frame 2. The support arm 21A supports the front lawn mowing mechanism 5A so as to be swingable around a rotation axis in the front-rear direction of the vehicle at the left end thereof, and the support arm 21B has a rotation axis in the front-rear direction of the vehicle at the right end thereof. The front lawn mowing mechanism 5B is supported so as to be swingable. For this reason, even if the ground is inclined in the left-right direction of the vehicle, the front lawn mowing mechanisms 5A and 5B can be inclined in accordance with the inclination.

  Electric cylinders 22A and 22B as actuators are attached to the support arms 21A and 21B. When the electric cylinder 22A expands and contracts, the left end portion of the support arm 21A moves in the vertical direction, and thereby the front lawn mowing mechanism 5A moves up and down. Similarly, when the electric cylinder 22B expands and contracts, the right end portion of the support arm 21B moves in the vertical direction, and thereby the front lawn mowing mechanism 5B moves up and down.

  The rear lawn mowing mechanism 6 is supported between the front wheels 3 </ b> A and 3 </ b> B and the rear wheel 4 so as to be movable up and down. The rear lawn mowing mechanism 6 lowers the lawn while in contact with the ground in front of the rear wheels 4. As with the front lawn mowing mechanisms 5A and 5B, the rear lawn mowing mechanism 6 includes a front roller 14, a rotary blade 15, a rear roller 16, a motor 17 that rotates the rotary blade 15, and a saturation roller 18. A receiving blade 19, a bucket 20, and a support arm 21C are provided. Further, it is lifted and lowered by a lifting mechanism (not shown) including the electric cylinder 22C and the like. As with the front lawn mowing mechanisms 5A and 5B, the rear lawn mowing mechanism 6 is also supported so as to be able to swing around the rotation axis in the front-rear direction of the vehicle, and matches the inclination of the ground in the left-right direction of the vehicle. Can be tilted.

  A display device (for example, a liquid crystal display device) 23 is provided below the steering wheel 8. The display device 23 displays various types of information such as information indicating the current state of the lawnmower vehicle 1 and also includes an operation unit that can input an operator's instruction. The raising / lowering of the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 and the starting / stopping of the rotary blade 15 provided thereon are instructed by the operator operating the operation unit of the display device 23. Is controlled accordingly. Information displayed on the display device 23 includes the traveling speed (vehicle speed) of the lawn mowing vehicle 1, the rotational speeds of the rotary blades 15 provided in each of the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 (units). The number of revolutions per hour), and information indicating the turf growth status.

  FIG. 3 is a block diagram showing a schematic configuration of the lawnmower vehicle 1. In FIG. 3, components corresponding to those shown in FIG. 1 are denoted with the same reference numerals. The lawnmower vehicle 1 includes an engine 24, hydraulic pumps 25 </ b> A and 25 </ b> B, and a generator 26. The hydraulic pumps 25 </ b> A and 25 </ b> B and the generator 26 are driven by the engine 24. The hydraulic pump 25A drives a hydraulic motor 28, and this hydraulic motor 28 drives the front wheels 3A and 3B. A differential mechanism 29 is provided between the front wheel 3A and the front wheel 3B. The differential between the inner and outer wheels when the lawnmower vehicle 1 turns is absorbed by the differential mechanism 29. The hydraulic pump 25 </ b> B drives a hydraulic cylinder 30, and the hydraulic cylinder 30 changes the steering angle of the rear wheel 4. The hydraulic cylinder 30 is driven with a drive amount corresponding to the rotation amount of the steering wheel 8 that is rotated by an operator, and the steering angle of the rear wheel 4 changes according to the drive amount of the hydraulic cylinder 30. That is, the lawnmower vehicle 1 has a steering mechanism 8A shown in FIG. The steering mechanism 8A is a so-called power steering mechanism.

  Here, a schematic configuration of the steering mechanism 8A will be described with reference to FIG. The steering mechanism 8A includes a hydraulic pump 25B, a hydraulic cylinder 30, a steering unit 8B, a steering arm 8C, and a hydraulic oil tank 8D. By rotating the steering wheel 8, a volume of hydraulic oil proportional to the rotation angle of the steering wheel 8 is sent to the hydraulic cylinder 30 to expand and contract the cylinder rod 30A. Then, the steering arm 8C is actuated (pushed and pulled) by the expansion and contraction of the cylinder rod 30A, and the steering angle of the rear wheel 4 changes. Since the steering arm 8C is operated by the expansion and contraction of the cylinder rod 30A of the hydraulic cylinder 30, the rotation angle of the steering wheel 8 and the steering angle of the rear wheel 4 are not proportional.

  As shown in FIG. 3, the electric power generated by the generator 26 driven by the engine 24 is stored in the battery 27. The generator 26 includes an AC / DC converter (not shown) that converts alternating current into direct current. The motors 17, 17, 17 and the electric cylinders 22 A, 22 B, 22 C are driven by the power of the battery 27. Each motor 17 rotates the rotary blades 15 of the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 to cut the lawn. The lawn mowing vehicle 1 travels by driving the hydraulic pump 25A and the hydraulic motor 28 by the engine 24 and rotating the front wheels 3A and 3B, and driving the motor 17 by the battery 27 and rotating the rotary blade 15 to cut the lawn. It is configured as a so-called hybrid lawn mowing vehicle.

  The lawnmower vehicle 1 includes a rudder angle sensor 31 that detects the rudder angle of the rear wheel 4, a vehicle speed sensor 32 that detects the vehicle speed of the lawn mower vehicle 1, motor drivers 17A, 17B, and 17C that drive the motors 17, Motor drivers 22A1, 22B1, and 22C1 that drive the electric cylinders 22A, 22B, and 22C, respectively, and a controller 33 that controls the operation of the lawnmower vehicle 1 are provided.

  As the steering angle sensor 31, for example, a rotary position sensor can be used. That is, the electrical resistance value accompanying the rotation of the rotor that rotates according to the steering angle of the rear wheel 4 can be measured, and the steering angle of the rear wheel 4 can be detected based on the measurement result. The vehicle speed sensor 32 can be a rotary encoder, for example. That is, the rotational speed per unit time of the hydraulic motor 28 can be measured by the rotary encoder, and the traveling speed (vehicle speed) of the lawn mowing vehicle 1 can be detected based on the measurement result.

  The control device 33 includes a microcomputer, a memory, and the like. Based on an operation instruction input from the display device 23, the control device 33 drives the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6, runs the lawn mowing vehicle 1, and the like. Control various operations. Further, the control device 33 controls the rotational speed (the number of revolutions per unit time) of the engine 24 according to the depression amount of the forward accelerator pedal 9 and the like. Further, the control device 33 drives the electric cylinders 22A, 22B, and 22C via the motor drivers 22A1, 22B1, and 22C1 based on a detection signal from the lawn mowing vehicle 1 or an inclination sensor that is not shown to detect the inclination of the road surface. To do. Further, as will be described later, the control device 33 determines the rotation speed (the number of rotations per unit time) of each motor 17 via the motor drivers 17A, 17B, and 17C based on signals from the steering angle sensor 31 and the vehicle speed sensor 32. Control. That is, the rotational speed (the number of revolutions per unit time) of the rotary blade 15 is controlled. Further, the control device 33 displays information indicating the state of the lawnmower vehicle 1 (for example, information indicating the vehicle speed, the rotation speed of the rotary blade 15, etc.) on the display device 23.

(Control of the rotational speed of the rotary blade 15)
Control of the rotational speed of the rotary blade 15 will be described with reference to FIG. As will be described below, the controller 33 cuts the front lawn based on the rudder angle θ of the rear wheel 4 detected by the rudder angle sensor 31 and the vehicle speed of the lawn mowing vehicle 1 detected by the vehicle speed sensor 32. The rotational speeds of the motors 17 provided in the mechanisms 5A and 5B and the rear lawn mowing mechanism 6 are controlled. Thereby, the lawn mowing vehicle 1 can make the lawn mowing state between the lawn mowing mechanisms 5A, 5B, 6 uniform when the lawn mowing vehicle 1 turns.

As shown in FIG. 5, when the rear wheel 4 has a steering angle θ, the turning radius R ₁ of the center M between the front wheels 3A and the front wheels 3B, which are driving wheels, and the turning on the inner wheel side of the front wheels 3A and the front wheels 3B. The radius R ₂ , the turning radius R ₃ on the outer wheel side, and the turning radius R ₄ of the rear wheel ₄ are expressed as the following expressions (1), (2), (3), and (4).

R ₁ = ((W + r · cos θ) / tan θ) + r · sin θ (1)
R ₂ = ((W + r · cos θ) / tan θ) + r · sin θ−T / 2 (2)
R ₃ = ((W + r · cos θ) / tan θ) + r · sin θ + T / 2 (3)
R ₄ = ((W + r · cos θ) / sin θ) (4)

W: Wheel base T: Tread r: Offset between the rotation center of the steering of the rear wheel 4 and the rotation center of the rear wheel 4 (in order to improve the straight running stability of the lawn mowing vehicle 1, the rotation of the steering of the rear wheel 4) The center is biased forward from the center of rotation of the rear wheel 4.)

As shown in FIG. 6, the origin O of the coordinate system is set at the center M of the front wheel 3A and the front wheel 3B, the X-axis (the front is negative, the rear is positive) in the front-rear direction of the lawn mowing vehicle 1, and the Y-axis ( Take the inside of the turning direction negative, the outside positive). At this time, the position coordinate (X ₀ , Y ₀ ) of the turning center P ₀ of the lawnmower vehicle 1 is expressed as the following equation (5).

Ｐｒ_１：前側芝刈り機構５Ａの回転刃１５の中心位置Ｐ_１（Ｘ_１，Ｙ_１）の旋回半径
Ｐｒ_２：前側芝刈り機構５Ｂの回転刃１５の中心位置Ｐ_２（Ｘ_２，Ｙ_２）の旋回半径
Ｐｒ_３：後側芝刈り機構６の回転刃１５の中心位置Ｐ_３（Ｘ_３，Ｙ_３）の旋回半径
When the position of the center of each rotary blade 15 of the front lawn mowing mechanism 5A, 5B and the rear lawn mowing mechanism 6 is defined as the center position P _i and the position coordinates (X _i , Y _i ) of the center position P _i are set, The turning radius Pr _{i with} respect to the turning center P _{0 at the} center position P _i is expressed as the following equation (6).

Pr ₁ : turning radius Pr ₂ of the center position P ₁ (X ₁ , Y ₁ ) of the rotary blade 15 of the front lawn mowing mechanism 5A: center position P ₂ (X ₂ , Y ₂ ) of the rotary blade 15 of the front lawn mowing mechanism 5B ) Turning radius Pr ₃ : turning radius of the center position P ₃ (X ₃ , Y ₃ ) of the rotary blade 15 of the rear lawn mowing mechanism 6

The center position P ₁ (X ₁ , Y ₁ ), the center position P ₂ (X ₂ , Y ₂ ), and the center position P ₃ (X ₃ , Y ₃ ) are respectively known positions determined by the design of the lawnmower vehicle 1. Coordinates.

The design value of the lawnmower vehicle 1 is, for example,

W (Wheelbase) = 1255mm
T (tread) = 1046.7 mm
r (the offset between the steering angle center and the rotation center of the rear wheel 4) = 30 mm
P ₁ (X ₁ , Y ₁ ) = P ₁ (−453 mm, −484.08 mm)
P ₂ (X ₂ , Y ₂ ) = P ₂ (−453 mm, 484.08 mm)
P ₃ (X ₃ , Y ₃ ) = P ₃ (699.5 mm, 0 mm)

, The ratio of Pr ₁ , Pr ₂ , Pr _{3 to} R _{1 at} the steering angle θ of the rear wheel 4 is as shown in the graph of FIG. For example, when the steering angle θ of the rear wheel 4 is 30 degrees, R ₁ : Pr ₁ : Pr ₂ : Pr ₃ = 1: 0.81: 1.23: 1.05.

  In this case, the control device 33 makes the respective rotary blades 15 of the front lawn mowing mechanism 5A, the front lawn mowing mechanism 5B, and the rear lawn mowing mechanism 6 for a “predetermined rotational speed” described next to the rotary blade 15. The rotation speed is rotated at 0.81: 1.23: 1.05 times.

  The “predetermined rotation speed” is a rotation speed (the number of rotations per unit time) determined according to the vehicle speed of the lawn mowing vehicle 1. If the rotational speed of the rotary blade 15 is slow relative to the vehicle speed of the lawn mowing vehicle 1, the mowing pitch of the lawn becomes large and it becomes easy for uncutting to occur. Therefore, the control device 33 controls the rotation of the rotary blade 15 so that the rotational speed of the rotary blade 15 increases as the vehicle speed increases so that the amount of grass left behind can be reduced and the grass can be cut appropriately. That is, in the lawnmower vehicle 1, the rotational speed of the rotary blade 15 is determined so that lawn mowing can be suitably performed according to the vehicle speed.

  The rotational speed at which the lawn mowing vehicle 1 can be suitably trimmed with respect to the vehicle speed is stored as a “predetermined rotational speed” for each vehicle speed as a table in the memory of the control device 33. Based on this table, the rotational speed of the rotary blade 15 can be controlled. Further, a calculation formula indicating the relationship between the vehicle speed of the lawn mowing vehicle 1 and the rotation speed of the rotary blade 15 capable of cutting the lawn appropriately with respect to the vehicle speed is stored in the memory of the control device 33, and the control device 33. May control the rotational speed of the rotary blade 15 based on this calculation formula.

The control device 33 measures the vehicle speed based on the measurement result of the vehicle speed sensor 32, determines a predetermined rotation speed of the rotary blade 15 according to the vehicle speed, and sets the rotary blade 15 of each lawn mowing mechanism to a predetermined rotation speed. On the other hand, the rotating blade 15 is rotated at a rotation speed corresponding to the ratio of the turning radii of the center positions P ₁ , P ₂ , P ₃ . As a result, the lawn mowing vehicle 1 can make the lawn mowing state uniform between the lawn mowing mechanisms while preventing the lawn mowing from being left even when turning.

The design values W, T, r, P ₁ (X ₁ , Y ₁ ), P ₂ (X ₂ , Y ₂ ) and P ₃ (X ₃ , Y ₃ ) are also stored in advance in the memory unit. ing. The control device 33 uses the equations (1) to (6) based on the steering angle θ of the rear wheel 4 detected by the steering angle sensor 31 and each design value, and the turning radius R ₁ of the lawnmower vehicle 1, The turning radii Pr ₁ , Pr ₂ , Pr ₃ of the center positions P ₁ , P ₂ , P ₃ of the rotary blade 15 are calculated, and the turning radius R ₁ and the center positions P ₁ , P ₂ , P _{3 of the} lawn mowing vehicle 1 are calculated. The ratio with the turning radii Pr ₁ , Pr ₂ , Pr ₃ is calculated. Then, the controller 33, a predetermined rotational _{speed, R 1: Pr 1: Pr} 2: rotational speed of the motor driver 17A of the lawn mowing mechanism on the basis of the Pr _3, 17B, and controls the 17C rotary blade 15 To control.

  When the steering angle θ is 0 degree, the lawn mowing vehicle 1 is in a straight traveling state, and there is no difference in turning speed between the rotary blades 15 of each lawn mowing mechanism. The rotary blade 15 is rotated at a predetermined rotation speed.

  As described above, the lawn mowing vehicle 1 includes a plurality of front lawn mowing mechanisms 5A, front lawn mowing mechanisms 5B, rear lawn mowing mechanisms 6 having a rotary blade 15 rotated by a motor 17 serving as a rotation driving unit, On the basis of the rudder angle sensor 31 as a rudder angle detection means for detecting the rudder angle θ of the rear wheel 4 as the steered wheel of the mowing vehicle 1, and the rudder angle θ detected by the rudder angle sensor 31, the front lawn mowing mechanism 5A. Each of the front lawn mowing mechanism 5B and the rear lawn mowing mechanism 6 includes a control device 33 that controls the rotational speed of the rotary blade 15.

Thus, the turning of the lawn mowing vehicle 1 is controlled by controlling the rotation of the rotary blades 15 of the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 according to the steering angle θ of the rear wheel 4 which is a steered wheel. The lawn mowing state between the lawn mowing mechanisms can be made more uniform. On the other hand, as shown in the above-mentioned Patent Document 1, according to the rotation angle (cut angle) of the steering wheel 8, the rotation blades 15 of the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 are rotated. Means for controlling are also conceivable. However, from the standpoint of preventing the impact received by the rear wheel 4 from the road surface from being directly transmitted to the steering wheel 8 and preventing the operation of the steering wheel 8 from being sensitively transmitted to the steering angle of the rear wheel 4, in general, steering. A play is provided between the rotation of the wheel 8 and the rudder angle of the rear wheel 4. That is, there is a possibility that the rotation of the steering wheel 8 and the turning radius of each lawn mowing mechanism do not correspond exactly (one to one). Therefore, when the rotational speed of the rotary blade 15 of each lawn mowing mechanism is controlled according to the rotation angle of the steering wheel 8, the rotational speed of the rotary blade 15 is set to the turning radius (Pr ₁ , Pr ₂₎ of each lawn mowing mechanism. , Pr ₃ ) may not correspond exactly (one-to-one). Therefore, there is a possibility that the lawn mowing state between the lawn mowing mechanisms during turning of the lawn mowing vehicle 1 cannot be sufficiently equalized.

On the other hand, when the rotational speed of the rotary blade 15 of each lawn mower is controlled based on the steering angle θ of the rear wheel 4, the steering angle θ of the rear wheel 4 and the center position P ₁ of each rotary blade 15. , P ₂ , P ₃ can be easily associated with the turning radii Pr ₁ , Pr ₂ , Pr ₃ on a one-to-one basis. For this reason, the turning radii Pr ₁ , Pr ₂ , Pr ₃ of the center positions P ₁ , P ₂ , P ₃ of each rotary blade 15 can be accurately reflected in the rotational speed of the rotary blade 15. Therefore, the lawn mowing state between the lawn mowing mechanisms during turning of the lawn mowing vehicle 1 can be suitably equalized.

Further, the control device 33 determines a predetermined position of the rotary blade 15 provided in each of the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 which are a plurality of lawn mowing mechanisms based on the steering angle θ of the rear wheel 4. The center position P _i is the turning radius Pr ₁ , Pr ₂ , Pr _{3 of the} center position P _i , and the predetermined position of the lawn mowing vehicle 1 is the center M of the front wheel 3A and the front wheel 3B. The ratio with ₁ is calculated, and the rotational speed of the rotary blade 15 of each lawn mowing mechanism is controlled based on this ratio.

Thus, based on the ratio between the turning radius _{Pr 1,} Pr 2, Pr ₃ of the center position _{P i} of the rotary blade 15 of the turning radius _{R 1} and the lawn mowing mechanism in a predetermined position of the mowing vehicle 1 (center M) Te, by controlling the rotational speed of the rotary blade 15 of the lawn mowing mechanism, respectively, to improve the accuracy of control of the rotational speed of the rotary blade 15 according to the turning speed of the center position P _i of each rotating blade 15 Can do. As a result, it is possible to make the lawn mowing state uniform between the front lawn mowing mechanisms 5A and 5B and the rear lawn mowing mechanism 6 when the lawn mowing vehicle 1 turns.

Mowing vehicle 1, a mowing vehicle 1 center M is a position of the symmetry center of the front wheel 3A and the front wheel 3B to a predetermined position, the turning radius Pr 1 of the turning radius R ₁ and the lawn mowing mechanism center _M, Pr Based on the ratio between ₂ and Pr ₃ , the rotational speed of the rotary blade 15 of each lawn mowing mechanism is controlled.

The control device 33 determines a predetermined rotation speed of the rotary blade 15 based on the vehicle speed of the lawn mowing vehicle 1. The lawnmower vehicle 1 at the time of turning has different turning speeds on the inside and outside of the turning. Therefore, it is preferable that the turning radius R ₁ is a position in the lawnmower vehicle 1 that has as little change as possible with respect to the vehicle speed when the lawnmower vehicle 1 travels straight. The center M is a symmetrical center position between the front wheels 3A and the front wheels 3B, and is a position in the lawnmower vehicle 1 in a turning state where there is little change in the vehicle speed with respect to the vehicle speed when the lawnmower vehicle 1 goes straight. Therefore, the center M is set as a predetermined position, and the respective ratios of the turning radii Pr ₁ , Pr ₂ , and Pr _{3 at} the predetermined positions of the rotary blades of the respective lawn mowing mechanisms with respect to the turning radius R _{1 at the} predetermined position (center M) By controlling the rotation speed of the rotary blade 15 of the lawn mowing mechanism, the lawn mowing state between the lawn mowing mechanisms can be made more uniform.

  The predetermined position may be the center of gravity of the lawn mowing vehicle 1 in addition to the center M between the front wheels 3A and the front wheels 3B as drive wheels.

  FIG. 8 is a diagram illustrating a configuration of a modified example of the lawnmower vehicle 1. As shown in FIG. 8, the lawnmower vehicle 1 uses a motor driver 50 to drive the front wheels 3A and 3B instead of a configuration in which the driving force of the engine is used to assist the driving of the front wheels 3A and 3B and the steering force of the rear wheels 4. The motor 51 may be configured to be an electric vehicle that is driven by the motor 51 and further assists the steering force of the rear wheels 4 by the motor 53 that is driven by the motor driver 52. Even when the lawnmower vehicle 1 is configured as an electric vehicle, the rotational speed of the rotary blade 15 of each lawnmower mechanism can be controlled in the same manner as the lawnmower vehicle 1 described in the above embodiment. .

  In the above-described embodiment and its modification, the lawnmower vehicle 1 configured to travel with three wheels has been described, but may be configured to travel with four wheels. When the lawnmower vehicle 1 travels with four wheels and either one of the front and rear wheels is a drive wheel, the predetermined position is preferably the center of the drive wheel. When both the front and rear wheels are driving wheels, it is preferable that the center position of the four wheels be the predetermined position of the lawn mowing vehicle 1.

  In the above-described embodiment and its modification, the predetermined position on the rotary blade 15 is set as the center position of the rotary shaft of the rotary blade 15. However, when the lawnmower vehicle 1 is turning, the turning speed of the same rotary blade 15 is different between the inside and the outside of the turn. Therefore, the predetermined position on the rotary blade 15 may be a position outside the center of the rotation axis of the rotary blade 15 in the turning direction. By doing in this way, the turning radius of the predetermined position in the rotary blade 15 becomes large. As described above, the rotation speed of the rotary blade 15 is set based on the magnitude of the turning radius at the predetermined position. Therefore, the rotational speed of the rotary blade 15 can be increased. By increasing the rotational speed of the rotary blades 15, it is possible to reduce the occurrence of uncut grass lawn in the rotational axis direction of each rotary blade 15.

  However, when the predetermined position on the rotary blade 15 is set to a position outside the turning direction from the center position of the rotation axis of the rotary blade 15, the predetermined position on the rotary blade 15 needs to be changed for each turning direction. On the other hand, by setting the predetermined position on the rotary blade 15 as the center position of the rotary shaft, it is possible to reduce the load of calculation processing for calculating the turning radius of the predetermined position.

In the above-described embodiment and its modification, the vehicle speed is detected based on the rotation of the front wheels 3A and 3B. However, the vehicle speed may be detected based on the rotation of the rear wheel 4. In this case, the turning radius R ₁ of the center M of the front wheel 3A and the front wheel 3B, based on the turning radius R ₄ of the rear wheel 4, and converts the moving speed of the center M, mowing speed of the vehicle 1 so It is preferable that

1 ... Lawn mower 4 ... Rear wheel (steering wheel)
5A, 5B ... Front lawn mowing mechanism (turf mowing mechanism)
6 ... Rear lawn mowing mechanism (lawn mowing mechanism)
15 ... Rotary blade 17 ... Motor (rotation drive means)
31 ... Rudder angle sensor (steering angle detection means)
33 ... Control device (control means)
θ: Steering angle P ₁ , P ₂ , P ₃ ... Center position of the rotary blade (predetermined position of the rotary blade)
M ... Center (predetermined position of lawn mower)

Claims (3)

In a lawnmower vehicle comprising a plurality of lawnmower mechanisms having a rotary blade rotated by a rotation drive means,
Rudder angle detection means for detecting the rudder angle of the steered wheels of the lawn mower vehicle;
Control means for controlling the rotational speed of the rotary blade for each of the plurality of lawn mowing mechanisms based on the rudder angle detected by the rudder angle detection means;
A lawnmower vehicle comprising: The lawnmower vehicle according to claim 1,
The control means calculates, based on the rudder angle, a ratio between a turning radius at a predetermined position of the rotary blade provided in each of the plurality of lawn mowing mechanisms and a turning radius at a predetermined position of the lawn mowing vehicle, Controlling the rotational speed of the rotary blades of the plurality of lawn mowing mechanisms based on this ratio,
A lawnmower vehicle characterized by that. The lawnmower vehicle according to claim 2,
The predetermined position of the lawn mowing vehicle is a symmetrical center position of wheels that serve as driving wheels.
A lawnmower vehicle characterized by that.

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