Walking type work machine

Abstract

To provide a walking type work machine capable of securing operational stability while enabling simplification of an operation.SOLUTION: A walking type work machine comprises: a driving source 11 capable of changing output rotation; an operation tool X capable of switching between first and second operational states by manipulation; a device-to-be-operated Y that switches between operation states by an operation of the operation tool X; and a control unit CU for controlling an actuation of the driving source 11. The control unit CU gradually increases the output rotation of the driving source 11 toward a setting speed, when the operation tool X switches to the second operational state from the first operational state.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a walk-behind working machine such as a walk-behind cultivator or a walk-behind rice transplanter. [Background technology]

[0002] Patent Document 1 discloses a walk-behind cultivator. The walk-behind working machine is equipped with an engine as a drive source, and the driving source drives the traveling device and the machine body while the working device performs work. The operator holds the control handle and walks together with the machine to control the machine body. A work clutch lever for turning the work clutch on and off, a throttle lever for adjusting the engine speed, and the like are provided near the control handle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-4843 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a walk-behind cultivator performs agricultural work in a field, it alternates between going straight and turning. For example, the cultivating work may be performed while going straight, and the machine may be turned when it reaches the edge of the field. When cultivating work is performed while going straight, the engine speed is high in order to increase the output, and the traveling speed is also high. On the other hand, when turning, it is easier to control the machine if the traveling speed is slow. In that case, the operator needs to operate both the clutch and the throttle lever, which makes the operation complicated.

[0005] In addition to turning, there are also cases where the vehicle alternates between forward and reverse driving, for example, when working near a ridge while driving straight ahead and then reversing to move to the next work location. In this case, the engine speed is high when driving forward, but when reversing, it is easier to control the vehicle at a slower driving speed. In this case, the operator must also change between forward and reverse driving and operate the throttle lever, which makes the operation complicated.

[0006] Therefore, it is conceivable to change the working state by operating one operating tool and change the output speed of the driving source (engine), thereby eliminating the troublesomeness of the operation. In this configuration, the output of the driving source is changed in addition to changing the operating state of the operated device by operating the operating tool. However, in this case, when increasing the output of the driving source by operating the operating tool, if the output is increased rapidly in consideration of workability, there is a risk that the operation by the operator will become unstable.

[0007] An object of the present invention is to provide a walk-behind working machine that can simplify its operation while ensuring operational stability. [Means for solving the problem]

[0008] The characteristic configuration of the walk-behind working machine of the present invention is that it is equipped with a drive source capable of changing the output rotation, an operating tool that can be switched between a first operating state and a second operating state by manual operation, an operated device whose operating state is switched by operating the operating tool, and a control device that controls the operation of the drive source, and when the operating tool is switched from the first operating state to the second operating state, the control device gradually increases the output rotation of the drive source toward a set speed.

[0009] According to the present invention, as the operating tool is switched between the first operating state and the second operating state, the operating state of the operated device is switched and the output rotation of the drive source is increased, so that the operation can be simplified. Also, at that time, the output rotation increases gradually. That is, since the output rotation is gradually increased, there is little risk of the operation by the operator who is piloting the aircraft becoming unstable.

[0010] Therefore, it has become possible to provide a walk-behind working machine that is capable of simplifying the operation while ensuring operational stability.

[0011] In the present invention, the operated device is provided with a turning operation device that can be switched between a turning operating state and a straight-line operating state, and it is preferable that the turning operation device switches from the turning operating state to the straight-line operating state when the operating tool is switched from the first operating state to the second operating state.

[0012] According to this configuration, the turning operation device switches from the turning operation state to the straight-line operation state in response to the operation of the operating tool, and the output rotation of the drive source gradually increases toward the set speed, i.e., the speed increases slowly. When switching from the turning state in which the vehicle travels at a low speed to the straight-line operation state, the drive speed increases slowly, so there is little risk of the operator operating the vehicle becoming unstable.

[0013] In the present invention, it is preferable that the turning operation device is a working clutch which switches on and off the transmission of power to a working device, the turning operating state being a clutch-off state, and the straight-travel operating state being a clutch-on state.

[0014] According to this configuration, when the turning operating state is switched to the straight-travel operating state, the working clutch is engaged and the rotation of the drive source gradually increases. Since the drive speed gradually increases when the working clutch is engaged, the working device does not immediately rotate at high speed after the clutch is engaged. As a result, it is possible to ensure operational stability.

[0015] In the present invention, it is preferable that left and right traveling devices are provided, the turning operating device is a differential mechanism for the left and right traveling devices, the turning operating state is a state that does not restrict the differential between the left and right traveling devices, and the straight-line operating state is a state that restricts the differential between the left and right traveling devices.

[0016] According to this configuration, the operation of the walk-behind work machine is simplified because both the gradual increase in the rotation speed of the drive source and the differential regulation of the differential mechanism can be realized by operating the operating tool. In addition, the increase in the rotation speed of the drive source and the differential regulation make it easy to work in a straight line.

[0017] In the present invention, it is preferable that, when the operating tool is switched from the second operating state to the first operating state, the control device reduces the output rotation of the drive source to a turning speed that is lower than the set speed.

[0018] According to this configuration, when switching from a straight traveling state to a turning state, the output rotation of the drive source is reduced, so that turning can be easily performed.

[0019] In the present invention, the operated device is provided with a forward / reverse switching mechanism that can be switched between a forward state and a reverse state, and it is preferable that the forward / reverse switching mechanism switches from the reverse state to the forward state when the operating tool is switched from the first operating state to the second operating state.

[0020] According to this configuration, when the operating tool is operated, the forward / reverse switching mechanism switches from the reverse state to the forward state, and the output rotation of the drive source gradually increases toward the set speed, i.e., the speed increases slowly. When the vehicle switches from the reverse state, in which the vehicle travels at a low speed, to the forward state, the drive speed increases slowly, so there is little risk of the operator operating the vehicle becoming unstable.

[0021] In the present invention, it is preferable that a target speed setting means is provided which sets a target speed of the drive source by manual operation, and that the control device reduces the output rotation of the drive source to a neutral speed which is lower than the target speed when the operating tool is switched from the first operating state to the second operating state, and gradually increases the output rotation of the drive source from the neutral speed to the target speed as the set speed when the operating tool is switched from the second operating state to the first operating state.

[0022] According to this configuration, when the forward / reverse switching mechanism switches from the forward state to the reverse state, it first passes through the neutral state and then switches to the reverse state. At that time, the output rotation of the drive source is reduced to a low neutral speed. Also, when switching from the reverse state to the forward state, the output rotation of the drive source is gradually increased toward the target speed. As a result, there is little risk of the operator's operation becoming unstable when switching from the forward state to the reverse state and when switching from the reverse state to the forward state.

[0023] In the present invention, it is preferable that the drive source is an engine equipped with an electronically controlled fuel supply device.

[0024] According to this configuration, it is possible to precisely adjust the amount of fuel supplied to the engine and the amount of intake air through electronic control, and it is possible to satisfactorily adjust the output rotation of the drive source (engine).

[0025] In the present invention, it is preferable that the drive source is an electric motor. According to this configuration, deterioration of the external environment can be prevented, and noise can be easily suppressed.

[0026] In the present invention, it is preferable that the drive source is a carburetor engine. According to this configuration, no devices such as a pump or a special injection device are required, and a simple configuration can be used. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a left side view showing the entire walk-behind cultivator. [Diagram 2] FIG. 2 is a plan view showing the entire walk-behind cultivator. [Diagram 3] FIG. 2 is a diagram showing a power transmission system and an operating system. [Figure 4] 4 is a flowchart showing the operation of the control device. [Diagram 5] 4 is a time chart showing a fluctuation state of engine output rotation; [Figure 6]FIG. 4 is a diagram showing the fluctuation state of engine output rotation. [Figure 7] FIG. 4 is a diagram showing the fluctuation state of engine output rotation. [Figure 8] FIG. 2 is a diagram showing a power transmission system and an operating system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of a walk-behind cultivator, which is an example of a walk-behind working machine according to the present invention, will be described with reference to the drawings. Note that the present invention is not limited to the following embodiment, and various modifications are possible without departing from the gist of the present invention.

[0029] In addition, unless otherwise specified, the front-rear and left-right directions in the explanation of this embodiment are described as follows: In other words, the forward traveling direction when the walk-behind cultivator is traveling for work (see arrow FR in Figs. 1 and 2) is "forward", the backward traveling direction (see arrow BK in Figs. 1 and 2) is "rear", the direction corresponding to the right side based on the forward posture in the front-rear direction (see arrow RH in Fig. 2) is "right", and similarly the direction corresponding to the left side (see arrow LH in Fig. 2) is "left".

[0030] [Overall structure] As shown in FIG. 1, the traveling body of the walk-behind cultivator is equipped with an engine 11 as a drive source mounted on an engine frame 10 that constitutes a part of the body frame 1. In this embodiment, the engine 11 is equipped with an electronically controlled fuel supply device FE (FIG. 3). The electronically controlled fuel supply device FE forcibly injects fuel into a combustion cylinder using an actuator and adjusts the amount of intake air using a throttle valve, and can change and adjust the rotation speed of the engine 11. In other words, the electronically controlled fuel supply device FE includes an electronically controlled fuel injection device. The electronically controlled fuel supply device FE also has the function of an electronic governor that suppresses fluctuations in the rotation speed of the engine 11. Therefore, there are advantages such as reduced influence of external environments such as temperature, stabilization of the operation of the engine 11, and realization of detailed control.

[0031] A transmission case 2, which constitutes the vehicle frame 1 together with the engine frame 10, is connected integrally to the rear side of the engine frame 10. The engine 11 and the transmission case 2 are connected together via a belt transmission mechanism 12 so as to be capable of transmitting power.

[0032] The transmission case 2 is formed in a bifurcated shape, including a front case 2A extending downward and a rear case 2B extending diagonally downward and rearward.

[0033] Left and right traveling devices 13 are supported on the lower part of the front case 2A via axles 20. In this embodiment, the traveling devices 13 are wheels. The traveling devices 13 may be devices of other forms, such as crawler traveling devices.

[0034] A working device 14 is supported on the rear case 2B via a drive shaft 21. In this embodiment, the working device 14 is a rotary tilling device. The working device 14 may be another type of device, such as a ridge maker or a seed sowing machine.

[0035] Power from the engine 11 is transmitted to a gear transmission mechanism (not shown) inside the transmission case 2 via a belt transmission mechanism 12. The belt transmission mechanism 12 is configured so that the power transmission can be turned on and off by a clutch operating arm 12a. The belt transmission mechanism 12 and the clutch operating arm 12a form a main clutch 31 (FIG. 3) that connects and disconnects the power transmission to the traveling drive system and the working drive system.

[0036] A working clutch 32, a running clutch 33, and a differential mechanism 34 are provided inside the transmission case 2 (see FIG. 3). Power from the main clutch 31 is branched and transmitted to the working clutch 32 and the running clutch 33.

[0037] The working clutch 32 turns on and off the power transmission to the working device 14. The traveling clutch 33 turns on and off the power transmission to the traveling device 13 via a differential mechanism 34. The differential mechanism 34 can regulate the differential between the left and right traveling devices 13. The working clutch 32 and the differential mechanism 34 are a turning operation device which is an example of an operated device Y which will be described later.

[0038] A main speed change lever 15 extends diagonally upward and rearward from the top of the transmission case 2. By operating this main speed change lever 15, the speed change operation and forward / reverse switching operation of the traveling device 13, as well as the forward / reverse rotation operation of the working device 14 can be performed.

[0039] A control handle 16 extends toward the rear of the aircraft from the rear of the transmission case 2. A turning lever 17, a stop switch 18, and a throttle lever 19 serving as a target speed setting means are disposed on the right side of the control handle 16. A main clutch lever 3 for switching on and off a main clutch 31 is disposed on the rear end side of the control handle 16.

[0040] The rotating lever 17 is used to operate the work clutch 32 and the differential mechanism 34, which are the operated devices Y, and is one example of the operating tool X.

[0041] When the swing lever 17 is in the ON position, the working clutch 32 is in a state where it does not transmit power (clutch disengaged), and the differential mechanism 34 is in a state where it does not restrict the differential movement of the traveling device 13 (diff-lock disengaged). When the swing lever 17 is in the OFF position, the working clutch 32 is in a state where it transmits power (clutch engaged), and the differential mechanism 34 is in a state where it restricts the differential movement of the traveling device 13 (diff-lock engaged).

[0042] A stop switch 18 is wired to the control system of the engine 11 for use in stopping the engine 11 .

[0043] The throttle lever 19 is used to operate the rotation speed of the engine 11 and is connected to a control device CU that controls the electronically controlled fuel supply device FE.

[0044] In the walk-behind cultivator configured as above, the operator operates the walk-behind cultivator by holding the control handle 16 and walks together with the moving walk-behind cultivator. Turning is performed by the operator turning the control handle to the left or right to change the direction of travel of the walk-behind cultivator.

[0045] [Power transmission system and operating system] FIG. 3 shows a power transmission system and an operating system of the walk-behind type cultivator of this embodiment.

[0046] The power transmission system will now be described. Power is transmitted from the engine 11 to the working device 14 via a main clutch 31, a transmission 2C, and a working clutch 32. Power is transmitted from the engine 11 to the traveling device 13 via the main clutch 31, a transmission 2C, a traveling clutch 33, and a differential mechanism 34. The transmission 2C transmits power from the engine 11 to the traveling device 13, and is capable of switching between forward and reverse traveling of the traveling device 13.

[0047] The operation system will now be described. The walk-behind cultivator of this embodiment is equipped with an engine 11 as a drive source capable of changing the output rotation, an operating tool X that can be switched between a first operating state and a second operating state by manual operation, an operated device Y whose operating state is switched by operating the operating tool X, and a control device CU that controls the operation of the engine 11. When the operating tool X is switched from the first operating state to the second operating state, the control device CU gradually increases the output rotation of the engine 11 toward a set speed.

[0048] A clutch detection sensor S1 is provided as a clutch detection means for detecting whether the main clutch 31 is in an engaged state or disengaged state, and a signal from the sensor S1 is transmitted to the control unit CU via a transmission line 3b. When an engaged state is detected based on the detection result of the clutch detection sensor S1, the control unit CU controls the operation of the engine 11 so that the target speed is reached, and when a disengaged state is detected, the control unit CU controls the operation of the engine 11 so that the set speed is reached which is lower than the target speed.

[0049] A shift detection switch S2 is provided as forward / reverse detection means for detecting whether the transmission 2C is in a forward or reverse state, and a signal from the switch S2 is transmitted to the control unit CU via a transmission line 15b. When a forward state is detected based on the detection result of the shift detection switch S2, the control unit CU controls the operation of the engine 11 so that the target speed is reached, and when a transition from the forward state to the reverse state is detected, the control unit CU controls the operation of the engine 11 so that the set speed is lower than the target speed. Then, when the state is switched from the reverse state to the forward state, the output rotation of the engine 11 is gradually increased from the neutral speed toward the target speed set by the throttle lever 19.

[0050] In this embodiment, a turning operation device (working clutch 32 and differential mechanism 34) switchable between a turning operation state and a straight-travel operation state is provided as the operated device Y, and the turning operation device (working clutch 32 and differential mechanism 34) switches from the turning operation state to the straight-travel operation state when the operating tool X (turn lever 17) switches from a first operation state to a second operation state. Also, a speed change device 2C switchable between a forward state and a reverse state is provided as the operated device Y, and switches from the reverse state to the forward state when the operating tool X (main speed change lever 15) switches from the first operation state (reverse position) to the second operation state (forward position).

[0051] A specific description will be given. The turning lever 17, which is an example of the operating tool X, is operated by the operator from the off position (corresponding to the second operating state) to the on position (corresponding to the first operating state) when the walk-behind cultivator turns, and is also operated by the operator from the on position (first operating state) to the off position (second operating state) when changing from the turning state to the straight-ahead state.

[0052] The swing lever 17 and the work clutch 32 are mechanically connected by a first operating wire 17a. The first operating wire 17a mechanically transmits the operation received by the swing lever 17 to the work clutch 32. The work clutch 32 is one of the operated devices Y. When the swing lever 17 is operated from the OFF position to the ON position, the work clutch 32 changes from a state in which it transmits power to a state in which it does not transmit power. This causes the working device 14 to stop operating. When the swing lever 17 is operated from the ON position to the OFF position, the work clutch 32 changes from a state in which it does not transmit power to a state in which it transmits power.

[0053] The swivel lever 17 and the differential mechanism 34 are mechanically connected by the second operation wire 17b. The second operation wire 17b mechanically transmits the operation received by the swivel lever 17 to the differential mechanism 34. The differential mechanism 34 is one of the operated devices Y. When the swivel lever 17 is operated from the OFF position to the ON position, the differential mechanism 34 changes from a state in which the differential between the left and right traveling devices 13 is restricted to a state in which the differential is not restricted. This allows the left and right traveling devices 13 to operate, making it easier for the operator to turn the walk-behind cultivator. When the swivel lever 17 is operated from the ON position to the OFF position, the differential mechanism 34 changes from a state in which the differential between the left and right traveling devices 13 is not restricted to a state in which the differential is restricted. Furthermore, the connection between the rotation lever 17 and the work clutch 32 or the differential mechanism 34 is not limited to a mechanical connection using an operating wire, and may instead be a configuration in which the work clutch 32 or the differential mechanism 34 is switched by an actuator that is operated by operating the rotation lever 17.

[0054] The rotating lever 17 is configured to electrically transmit the operation received to the control unit CU. That is, a switch (e.g., a limit switch) (not shown) in contact with the rotating lever 17 detects that the rotating lever 17 has been operated to the ON position, and a signal from the switch is transmitted to the control unit CU via a transmission line 17c.

[0055] The throttle lever 19 is configured to transmit the operation received by the throttle lever 19 to the control unit CU. That is, a sensor (not shown) is provided to detect the position of the throttle lever 19, and the signal from the sensor is transmitted to the control unit CU via a transmission line 19a.

[0056] The main clutch lever 3 and the main clutch 31 are mechanically connected by a third operating wire 3a. The third operating wire 3a mechanically transmits the operation received by the main clutch lever 3 to the main clutch 31. When the main clutch lever 3 is operated to the disengaged position, the main clutch 31 enters a clutch-disengaged state in which power transmission is cut off. When the main clutch lever 3 is operated to the engaged position, the main clutch 31 enters a clutch-engaged state in which the power of the engine 11 is transmitted to the downstream transmission side. In this state, the power of the engine 11 is transmitted to the traveling device 13 via the traveling clutch 33 and the differential mechanism 34, and is also transmitted to the working device 14 via the working clutch 32, allowing tilling work to be performed while traveling.

[0057] It is configured to electrically transmit the operation received by the main clutch lever 3 to the control unit CU. That is, a clutch detection sensor S1 is provided near the main clutch lever 3, which comes into contact with the lever 3 when the lever is operated to the clutch-engaged position and detects this. The clutch detection sensor S1 is, for example, a limit switch. It is configured to transmit a signal from the clutch detection sensor S1 to the control unit CU via a transmission line 3b.

[0058] The control unit CU is a so-called ECU, and includes a memory device ME and a CPU (not shown). The memory device ME includes an HDD and non-volatile RAM, and stores programs for controlling the walking type cultivator, permanent data, and temporary data. The functions of the control unit CU described below are realized by the CPU executing the programs.

[0059] The control unit CU controls the electronically controlled fuel supply unit FE based on the operation received by the throttle lever 19 to control the rotation speed of the engine 11.

[0060] In this embodiment, when the operating device X (swing lever 17, main shift lever 15) is switched from the second operating state (off position, forward state) to the first operating state (on position, reverse state), the control device CU reduces the output rotation of the drive source (engine 11) to a turning speed that is slower than the set speed. Also, when the operating device X (swing lever 17, main shift lever 15) is switched from the first operating state (on position, reverse state) to the second operating state (off position, forward state), the control device CU gradually increases the output rotation of the drive source (engine 11) toward the set speed.

[0061] That is, when the turning lever 17 (operating device) is switched from the OFF position (second operating state) to the ON position (first operating state), the control device CU reduces the output rotation of the engine 11 to a turning speed that is lower than the set speed set by the throttle lever 19. The turning speed is set to a low value that allows turning travel in a stable posture. For example, it is a speed slightly higher than the idling speed. The turning speed may be the idling speed, or may be an intermediate speed between the idling speed and the maximum speed.

[0062] When the swing lever 17 (operating tool) is switched from the ON position (first operating state) to the OFF position (second operating state), the control device CU gradually increases the output rotation of the engine 11 toward the set speed. In other words, the control device CU controls the electronically controlled fuel supply device FE so that the output rotation of the engine 11 is gradually increased toward the target speed from the reduced swing speed.

[0063] When the turning lever 17 is operated to the off position (first state), the control unit CU reads out the pre-change control state from the memory device ME. Then, based on the read pre-change control state, the control unit CU gradually increases the output rotation toward the set speed so that the electronically controlled fuel supply device FE is in the pre-change control state (a state in which the engine output rotation becomes the target speed).

[0064] [Operation and control flow of walking tiller] The operation of the walk-behind cultivator and the flow of control based on the switching operation of the turning lever 17 performed by the control device CU will be described with reference to the flow chart of FIG.

[0065] When the walk-behind cultivator works in a field, it alternates between moving straight and turning. For example, an operator performs tilling work while moving the walk-behind cultivator straight in a direction parallel to the long side of the field. When the walk-behind cultivator reaches the edge of the field, the operator turns the turning lever 17 and then turns the walk-behind cultivator.

[0066] The electronically controlled fuel supply device FE is controlled to control the engine 11 output rotation to a target speed set by the throttle lever 19, thereby controlling the engine speed. When performing tilling work with the implement 14 while traveling, the traveling load and the drive load of the implement 14 are large, so that the target speed is set to a value that results in a large output rotation close to the maximum output of the engine 11, taking into consideration the work efficiency.

[0067] The control unit CU continues to monitor the operation state of the swing lever 17 until the swing lever 17 is turned on and operated (step #01: No).

[0068] When the turning lever 17 is operated to the ON position (second state) (Step #01: Yes), the control unit CU stores the pre-change control state of the electronically controlled fuel supply device FE in the memory device ME (Step #02). The pre-change control state is, for example, the rotation speed of the engine 11 and the control parameters (fuel injection amount, fuel injection time, etc.) of the electronically controlled fuel supply device FE.

[0069] Following step #02, the control unit CU controls the electronically controlled fuel supply unit FE to decelerate so that the output rotation of the engine 11 decreases to a turning speed (step #03).

[0070] By turning on the turning lever 17, the working clutch 32 is disengaged, the differential mechanism 34 is permitted to operate, and the RPM of the engine 11 is reduced. This allows the operator to easily turn the walk-behind cultivator.

[0071] When the walking cultivator has completed its turning and is ready to resume tilling work by moving in a straight line, the operator turns the turning lever 17.

[0072] After completing step #03, the control unit CU continues to monitor the operating state of the turning lever 17 until the turning lever 17 is turned (step #04: No).

[0073] When the turning lever 17 is operated to the off position (first state) (step #04: Yes), the control unit CU reads out the pre-change control state of the electronically controlled fuel supply device FE from the memory device ME (step #05).

[0074] Following step #05, the control unit CU performs speed increase control on the electronically controlled fuel supply device FE so that the output rotation of the engine 11 becomes the target speed (step #06). In this speed increase control, the electronically controlled fuel supply device FE is controlled so that the output rotation of the engine 11 gradually increases from the turning speed toward the target speed.

[0075] Although a flow chart is not shown, when the forward drive state is switched to the reverse drive state in response to the operation of the main shift lever 15, the output rotation of the engine 11 is reduced, and when the reverse drive state is switched to the forward drive state, the output rotation of the engine 11 is gradually increased toward the target speed in a similar manner.

[0076] The control contents of the control unit CU will be described with reference to the time chart of FIG. If the first set value M1 is set by the throttle lever 19 at the start of work with the main clutch 31 engaged, the control unit CU controls the electronically controlled fuel supply unit FE so that the output speed of the engine 11 becomes the first target speed N1 corresponding to the first set value M1. Note that at this time, if the engine 11 is in an unloaded state, the output speed of the engine 11 becomes the first target speed N1, but when tilling work is being performed, the driving load is large, so the actual rotation speed of the engine 11 may be lower than the first target speed N1.

[0077] When working while driving forward, if the throttle lever 19 is set to a second set value M2 that is lower than the first set value M1, the control unit CU controls the electronically controlled fuel supply unit FE so that the output speed of the engine 11 becomes a second target speed N2 that corresponds to the second set value M2.

[0078] When starting work, the transmission 2C is switched from the neutral state to the forward state. At this time, even if the shift detection switch S2 detects that the transmission has been switched to the forward state, the output speed of the engine 11 is maintained at the first target speed N1.

[0079] When the shift detection switch S2 detects a transition from a forward state to a reverse state during work while traveling forward, the electronically controlled fuel supply device FE is controlled so that the output speed of the engine 11 becomes a third target speed N3, which is a neutral speed lower than the first target speed N1. When the vehicle switches to the reverse state in this way, the output speed of the engine 11 can be reduced without operating the throttle lever 19, and reverse travel can be started at a low speed without bothersome operation. The third target speed N3 may be a value close to the idling speed, which is the lower limit value in terms of the characteristics of the engine 11, but if the third target speed N3 is a value higher than the idling speed, it is easier to return to work.

[0080] When the main shift lever 15 is switched from the reverse position (second operating state) to the forward position (first operating state) and this is detected by the shift detection switch S2, the output rotation of the engine 11 is gradually increased from the third target speed N3 toward the first target speed N1. However, when the main shift lever 15 is switched from the forward position to the reverse position, if a target speed lower than the third target speed N3 is set by the throttle lever 19, the output rotation of the engine 11 is not reduced. Also, when the main shift lever 15 is switched from the reverse position (second operating state) to the forward position (first operating state), if a value close to or lower than the third target speed N3 is set by the throttle lever 19, the speed increase control (gradual increase) is not performed. For example, when a value lower than a predetermined threshold value is set at the throttle lever 19, when the main shift lever 15 is switched from the reverse position (second operating state) to the forward position (first operating state), the control device CU does not perform speed increase control (gradual increase), but controls the electronically controlled fuel supply device FE so that the output rotation of the engine 11 becomes the value set at the throttle lever 19.

[0081] Also, when the work is interrupted midway and the main clutch 31 is switched to the disengaged state, the control unit CU controls the electronically controlled fuel supply unit FE so that the output speed of the engine 11 becomes a fourth target speed N4, which is a set speed lower than the first target speed N1. In this way, when the main clutch 31 is in the disengaged state, the output speed of the engine 11 can be reduced without operating the throttle lever 19, and it is possible to suppress wasteful consumption of fuel and reduce noise without the hassle of operation. The fourth target speed N4 may be a value close to the idling speed or a value higher than the idling speed. The fourth target speed N4 may be lower than the third target speed N3 as shown in FIG. 5, or may be higher than the third target speed N3.

[0082] When the swing lever 17 is operated to the ON position to perform swing during work, the output rotation of the engine 11 is suddenly reduced to a swing speed (for example, the third target speed N3). The swing speed may be a value close to the idling speed, which is the lower limit value in terms of the characteristics of the engine 11, but if the value is a little higher than the idling speed, it is easier to return to work. When the swing lever 17 is switched from the ON position to the OFF position, the output rotation of the engine 11 gradually increases. That is, it slowly increases from the third target speed N3 (swing speed) to the first target speed N1. However, when the swing lever 17 is switched from the ON position to the OFF position, if a value close to or lower than the third target speed N3 is set in the throttle lever 19, the speed increase control (gradual increase) is not performed. For example, when a value lower than a predetermined threshold value is set on the throttle lever 19, the control unit CU does not perform speed increase control (gradual increase) when the turning lever 17 is switched from the ON position to the OFF position, but controls the output rotation of the engine 11 to the value set on the throttle lever 19.

[0083] As a control process for gradually increasing the speed, for example, during the elapse of a set unit time from the time when the turning lever 17 is switched from the ON position to the OFF position, an intermediate value (first intermediate value) between the first target speed N1 and the second target speed N2 (turning speed) is set as a control target value for the output rotation of the engine 11, and the electronically controlled fuel supply device FE is controlled so that the output rotation of the engine 11 becomes the first intermediate value. Furthermore, during the elapse of the next set unit time after the set unit time has elapsed, an intermediate value (second intermediate value) between the first target speed N1 (set speed) and the first intermediate value is set, and the electronically controlled fuel supply device FE is controlled so that the output rotation of the engine 11 becomes the second intermediate value. Thereafter, in the same manner, the electronically controlled fuel supply device FE is controlled so that the intermediate value between the current value of the output rotation of the engine 11 and the first target speed N1, which is the final target, is set as the next target speed. When the difference between the current value of the output rotation of the engine 11 and the first target speed N1 becomes smaller than the set amount, the first target speed N1 is set as the target speed. The set unit time is 50 msec. However, the set unit time is not limited to 50 msec and various other times can be set.

[0084] When executing control in this manner, the first target speed N1 is not always set as the target speed, but the target speed is initially set to a small value and then gradually increased, thereby adjusting the speed so that the output rotation of the engine 11 is gradually increased while preventing a sudden increase.

[0085] According to the illustrated method of increasing the speed, the speed change is large at the beginning of the speed increase, and the change becomes smaller as time passes. However, the present invention is not limited to this configuration, and the method of increasing the speed may be changed in various ways. For example, as shown in Fig. 6, the speed change may be small at the beginning of the speed increase, and the change may become larger as time passes, or as shown in Fig. 7, the increase amount per unit time may be constant.

[0086] By turning the turning lever 17, the working clutch 32 is engaged, the differential mechanism 34 is put into a state in which operation is restricted, and the RPM of the engine 11 increases to the RPM before turning. This makes it easy for the operator to move the walk-behind cultivator in a straight line and perform farm work.

[0087] [Another embodiment] The present invention is not limited to the configurations exemplified in the above-described embodiments. Other representative embodiments of the present invention will be described below.

[0088] (1) In the above first embodiment, one turning lever 17 is provided as the operating device X, and when the turning lever 17 is switched from a first operating state to a second operating state, both the work clutch 32 and the differential mechanism 34 are switched from a turning operating state to a straight-line operating state. However, instead of this configuration, the operating device X may be provided separately with a clutch operating lever capable of switching and operating the work clutch 32, and a differential operating lever capable of switching and operating the differential mechanism 34.

[0089] (2) As shown in FIG. 8, as an example of an operated device Y, a turning operation device may be provided with a side clutch 41 that can be turned on and off independently for each of the left and right traveling devices 13 instead of the differential mechanism 34, and as an operating tool X, a side clutch lever 42 that commands the turning on and off of the side clutch 41 may be provided instead of the turning lever 17.

[0090] A fourth operation wire 42a that mechanically transmits the operation received by the side clutch lever 42 to the side clutch 41, and a transmission line 42b that transmits the operation received by the side clutch lever 42 to the control device CU are provided. The control device CU controls the electronically controlled fuel supply device FE so that the rotation speed of the engine 11 decreases to a turning speed in response to receiving an operation of the side clutch lever 42 from the engaged position (first operation state) to the disengaged position (second operation state). The control device CU controls the electronically controlled fuel supply device FE so that the rotation speed of the engine 11 gradually increases to a target speed set by the throttle lever in response to receiving an operation of the side clutch lever 42 from the disengaged position (second operation state) to the engaged position (first operation state). The control contents by the control device CU are the same as those in the first embodiment.

[0091] (3) The engine 11 may not include the electronically controlled fuel supply device FE. In other words, the engine 11 may be one in which the amount of fuel supplied to the engine 11 is adjusted by a mechanical carburetor or the like.

[0092] (4) The walk-behind cultivator may be provided with an electric motor as a drive source instead of the engine 11.

[0093] (5) The running clutch 33 is not necessarily required, and the running clutch 33 may not be provided. [Industrial Applicability]

[0094] The present invention is applicable to walk-behind working machines, such as walk-behind cultivators, walk-behind rice transplanters, and walk-behind vegetable seedling transplanters. [Explanation of symbols]

[0095] 11 Engine (power source) 13 Running gear 19 Throttle lever (means for setting target speed) 32 Working clutch 34 Differential mechanism 40 Forward / forward switching mechanism CU control device FE electronic control fuel supply device X Operating Tools Y Operated device

Claims

1. A drive source capable of changing output rotation; an operating tool that can be manually switched between a first operating state and a second operating state; an operated device whose operating state is switched by operating the operating tool; A control device that controls the operation of the drive source is provided. The control device is a walk-behind working machine that, when the operating tool is switched from the first operating state to the second operating state, gradually increases the output rotation of the drive source toward a set speed.

2. As the operated device, a turning operation device switchable between a turning operating state and a straight-ahead operating state is provided, 2. The walk-behind work machine according to claim 1, wherein the turning operation device is switched from the turning operating state to the straight-traveling operating state when the operating tool is switched from the first operating state to the second operating state.

3. 3. The walk-behind work machine according to claim 2, wherein the turning operation device is a work clutch that switches on and off the transmission of power to the work device, the turning operating state being a clutch-off state, and the straight-travel operating state being a clutch-on state.

4. Equipped with left and right running gear, The turning operation device is a differential mechanism for the left and right traveling devices, 3. The walk-behind working machine according to claim 2, wherein the turning operating state is a state in which differential movement between the left and right traveling devices is not restricted, and the straight-travel operating state is a state in which differential movement between the left and right traveling devices is restricted.

5. 3. The walk-behind working machine according to claim 2, wherein the control device reduces the output rotation of the drive source to a turning speed that is slower than the set speed when the operating tool is switched from the second operating state to the first operating state.

6. The operated device is provided with a forward / reverse switching mechanism that can be switched between a forward state and a reverse state, 2. The walk-behind working machine according to claim 1, wherein the forward / reverse switching mechanism switches from the reverse state to the forward state when the operating tool switches from the first operating state to the second operating state.

7. a target speed setting means for manually setting a target speed of the driving source is provided; The control device includes: When the operating tool is switched from the first operating state to the second operating state, the output rotation of the drive source is reduced to a neutral speed which is lower than the target speed, 7. The walk-behind working machine according to claim 6, wherein when the operating tool is switched from the second operating state to the first operating state, the output rotation of the drive source is gradually increased from the neutral speed toward the target speed as the set speed.

8. 8. The walk-behind work machine according to claim 1, wherein the drive source is an engine equipped with an electronically controlled fuel supply device.

9. 8. The walk-behind work machine according to claim 1, wherein the drive source is an electric motor.

10. 8. The walk-behind work machine according to claim 1, wherein the drive source is a carburetor engine.

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